Valve timing changing device

Description

TECHNICAL FIELD

[0001] The present invention relates to a valve timing changing device which changes open-close timing (i.e., valve timing) of an intake valve or an exhaust valve of an internal combustion engine in accordance with drive conditions, and in particular, relates to a vane-type valve timing changing device which utilizes fluid pressure such as oil pressure as drive force.

BACKGROUND ART

[0002] There has been known a traditional valve timing changing device including a housing rotor (i. e. , a chain sprocket, a shoe housing and a front plate) which is rotated in synchronization with a crank shaft, a vane rotor which is rotated in synchronization with a cam shaft and which is accommodated in an accommodation room of the housing rotor as being relatively rotatable in a predetermined angle range (between the most-advanced position and the most-retarded position) while separating the accommodation room into an advancing chamber and a retarding chamber, a lock mechanism which locks the vane rotor against the housing rotor at the most-retarded position at the time of engine starting, a switching valve which controls supplying and discharging of operating oil against the advancing chamber and the retarding chamber, and the like. Here, the lock mechanism includes a stopper pin being movable against the vane rotor in a direction of the axis line of the cam shaft, a stopper hole formed at the housing rotor (e.g., the front plate) to have the protruded stopper pin fitted thereto, and a spring which urges the stopper pin to be fitted to the stopper hole. At the time of engine starting, the vane rotor is locked to be rotated integrally with the housing rotor by having the stopper pin fitted to the stopper hole at the most-retarded position. When oil pressure in the retarding chamber is increased, the locking of the vane rotor against the housing rotor is released as the stopper pin being disengaged from the stopper hole by being pressed against urging force of the spring owing to the oil pressure (for example, see Patent document 1) .

[0003] Further, there has been known another valve timing changing device including a housing rotor (e.g., an external rotor, a front plate, a rear plate and a timing sprocket) which is rotated in synchronization with a crank shaft, a vane rotor (e.g., an internal rotor) which is rotated in synchronization with a cam shaft and which is accommodated in an accommodation room of the housing rotor as being relatively rotatable in a predetermined angle range (between the most-advanced position and the most-retarded position) while separating the accommodation room into an advancing chamber and a retarding chamber, a lock mechanism which locks the vane rotor against the housing rotor at the most-retarded position at the time of engine starting, a switching valve which controls supplying and discharging of operating oil against the advancing chamber and the retarding chamber, and the like. Here, the lock mechanism includes a lock plate capable of being protruded and retracted radially against the vane rotor, a receptive groove formed at the vane rotor to have the protruded lock plate fitted thereto, and a torsion spring which urges the lock plate to be fitted to the receptive groove). At the time of engine starting, the vane rotor is locked to be rotated integrally with the housing rotor by having the lock plate fitted to the receptive groove at the most-retarded position. When oil pressure in the retarding chamber is increased, the locking of the vane rotor against the housing rotor is released as the lock plate coming out from the receptive groove against urging force of the torsion spring (for example, see Patent document 2).

[0004] In each device of the above, the lock mechanism (e.g., the stopper pin or the lock plate, the spring exerting urging force, and the like) which performs protruding and retracting at slide boundary faces of the vane rotor and the housing rotor is arranged in the accommodation room which accommodates the vane rotor. Accordingly, volume for arranging the lock mechanism is required for the vane rotor or the housing rotor.
Therefore, it has been difficult to widely set a phase adjustment angle as satisfying requirements owing to limitation of a relatively rotatable angle of the both, that is, the phase adjustment angle between the most-advanced position and the most-retarded position by the amount of the volume for arranging the lock mechanism.
Further, in the above devices, the vane rotor (i.e., the cam shaft) is maintained at the most-retarded position in a range of the phase adjustment angle against the housing rotor at the time of engine starting. However, there has been a requirement to maintain the vane rotor (i.e., the cam shaft) at a specified intermediate position in the range of the phase adjustment angle depending on a type or characteristics of an engine or in consideration of further improvement of startability.
Patent document 3 describes a valve timing controller. The valve timing controller comprises a stopper mechanism and a lock mechanism including a lock member assembled with a housing member and a tip portion of which is always projecting towards a rotor member, a free recess portion formed on the rotor member and accommodating the tip portion of the lock member while allowing the relative rotation of the housing member and the rotor member, a stopper surface formed on one end surface in circumferential direction of the free recess portion and defining a initial phase by the contact with the tip portion of the lock member, a lock recess portion formed continuously along the stopper surface and being capable of accommodating the tip portion of the lock member with restricting the movement thereof in circumferential direction at the initial phase, and a lock spring; biasing the lock member towards the lock recess portion.
Patent document 4 relates to a lock mechanism for a valve timing regulation device which regulates the timing of the opening and closing of engine valves, the lock mechanism locks or releases a first rotating body and a second rotating body in response to the operational condition of an engine. The lock mechanism includes a radial groove provided in either the first rotating body or the second rotating body and extending in a radial direction of the rotating body. A locking member is slidably inserted into the radial groove, and the locking member is urged towards a center of the rotating body by an urging means. An oil pressure is applied to the locking member in a direction opposite to the urging direction. In such a way, it is possible to assemble the locking member onto an end face in an axial direction other than a vane or a shoe in either the first rotating body or the second rotating body, as a result, each vane or each shoe can be formed with approximately the same circumferential length. Thus, it is possible to expand the angular range to be regulated by the valve timing regulation device and to reduce the degree of unbalance in the device by a large amount.
Patent document 5 relates to a variable valve timing control device. The variable valve timing control device, without using a return spring as self-reset driving force to an intermediate lock position, by converting a phase in both ignition timing advance and ignition timing delay directions from the intermediate lock position is described. A phase variable control device controls phase conversion being a relative rotational position of a sprocket and a vane rotor, and is provided with a power transmission mechanism capable of selecting an ignition timing delay directional lock releasing state of allowing relative rotation of the sprocket and the vane rotor only in one direction, an ignition timing advance directional lock releasing state of allowing only the reverse rotation direction, a both directional lock state of not allowing both directions of one direction and the reverse rotation direction and a both directional lock release state of allowing both directions of the one direction and the reverse rotation direction. A piston is also arranged for switching the both directional lock state and the both directional lock release state. Wedge engagement in the first circumferential direction and wedge engagement of the second circumferential direction are alternately released in a process of shifting to the both directional lock release state from the both directional lock state by driving of the piston.

Cited Document

Patent Document

[0005] 

Patent document 1: Japanese Patent 3146956

Patent document 2: Japanese Patent 4320903

Patent document 3: EP 1 087 107 A

Patent document 4: US-2001/011534 A

Patent document 5: JP 2007-255258 A

SUMMARY OF THE INVENTION

[0006] The invention is defined by the subject-matter of independent claim 1. The dependent claims are directed to advantageous embodiments.

ADVANTAGES OF THE INVENTION

[0007] Advantageously, for performing phase control of a vane rotor (i.e., phase changing in a phase adjustment angle range between the most-advanced position and the most-retarded position), it is provided a valve timing changing device capable of improving engine startability, preventing rattling etc. at the time of engine starting, and performing the phase control widely in accordance with engine drive conditions as the phase adjustment angle being set wider, while achieving structural simplification, reduction of part count, miniaturization of the entire device and the like.

[0008] To change open-close timing of an intake valve or an exhaust valve of which open-close driving is performed by a cam shaft, a valve timing changing device advantageous includes a housing rotor which is rotated on an axis line of a cam shaft as being interlocked with rotation of a crank shaft, a vane rotor which is accommodated in an accommodation room of the housing rotor as being relatively rotatable in a predetermined angle range while separating the accommodation room into a advancing chamber and a retarding chamber and which is rotated integrally with the cam shaft, an advancing passage which passes fluid as being communicated with the advancing chamber, a retarding passage which passes fluid as being communicated with the retarding chamber, and a lock mechanism which locks the vane rotor against the housing rotor at a specified position in the predetermined angle range. Here, the housing rotor is formed to define an isolation room isolated from the accommodation room which accommodates the vane rotor, and the lock mechanism is arranged in the isolation room.
According to the structure, the lock mechanism which locks the vane rotor (i.e., the cam shaft) against the housing rotor at the specified position in the predetermined angle range is arranged in the isolation room isolated from the accommodation room which accommodates the vane rotor. Therefore, compared to a traditional device with a lock mechanism being protruded and retracted against a slide boundary face in an accommodation room which accommodates a vane rotor, volume for arranging the lock mechanism becomes unnecessary and the phase adjustment angle between the most-advanced position and the most-retarded position can be set wider by the amount of the volume. Accordingly, it is possible to perform phase control widely if required.
In particular, when a thick vane accommodating a pin for locking is to be maintained at an intermediate position in the accommodation room at the time of starting as in the related art, a sufficient control angle for phase adjustment from the starting position to the advance side cannot be ensured. On the contrary, in the present invention, since extra thickness is not required for the vane, the angle of phase control (i.e., the phase adjustment angle) can be sufficiently ensured. In particular, it is possible to sufficiently ensure the angle required for performing phase control (i.e., the phase adjustment angle) to the advance side from the starting.

[0009] In the above structure, it is also possible that the lock mechanism locks the vane rotor at the specified intermediate position in the predetermined angle range at the time of engine starting.
According to the structure, the vane rotor (i.e., the cam shaft) is to be located at the intermediate position owing to the lock mechanism at the time of engine starting (i.e., cranking). Therefore, the engine can be smoothly started without unnecessary load while preventing occurrence of rattling. In addition, even after starting (i.e., complete combustion) of the engine, phase control can be smoothly performed while preventing unnecessary load.

[0010] In the above structure, it is also possible that the housing rotor includes a housing member having an isolation wall which isolates the isolation room from the accommodation room, and a cover member formed as being detachably attachable to the housing member to define the isolation room in cooperation with the isolation wall.
According to the structure, since the isolation room in which the lock mechanism is arranged is defined by the isolation wall of the housing member and the cover member which is detachably attachable to the housing member, assembling operation and disassembling operation of the lock mechanism can be easily performed in a state that the vane rotor is assembled in the accommodation room of the housing member.

[0011] In the above structure, it is also possible that the lock mechanism includes a lock cam connected to the vane rotor via a penetration hole which is formed at the isolation wall to be integrally rotated, and a lock bar which is movably arranged against the housing rotor and which is capable of being locked as being engaged with the lock cam owing to urging force and releasing the locking owing to fluid pressure.
According to the structure, the vane rotor can be locked against the housing rotor at the specified position (i.e., the intermediate position) as the lock cam being locked by the lock bar at the time of engine starting (i.e. cranking), and then, the locking due to the lock bar can be released owing to the fluid pressure after starting (i.e., complete combustion) of the engine. That is, since the vane rotor is surely maintained at the specified position (i.e., the intermediate position) by the lock mechanism, the engine can be started more surely. In addition, since the vane rotor is not directly locked by the lock mechanism, vane portions of the vane rotor can be thinned and design flexibility and layout flexibility can be increased.

[0012] In the above structure, the valve timing changing device may be further provided with an urge spring which exerts urging force to lock the lock bar to be engaged with the lock cam. Here, the lock bar may include an advance-restraining lock bar which is engaged with the lock cam to restrain the vane rotor from being rotated to an advance side, and a retard-restraining lock bar which is engaged with the lock cam to restrain the vane rotor from being rotated to a retard side. Further, the urge spring may include an advance-restraining urge spring which urges to lock the advance-restraining lock bar as being engaged with the lock cam, and a retard-restraining urge spring which urges to lock the retard-restraining lock bar as being engaged with the lock cam. Furthermore, the housing rotor may include an advance-restraining communication passage which guides fluid pressure to the advance-restraining lock bar in the isolation room to release locking as being communicated with the advancing chamber or the advancing passage, and a retard-restraining communication passage which guides fluid pressure to the retard-restraining lock bar in the isolation room to release locking as being communicated with the retarding chamber or the retarding passage.
According to the structure, in a state that fluid pressure is not applied to the advance-restraining communication passage and the retard-restraining communication passage, the advance-restraining lock bar restrains the lock cam (i.e., the vane rotor) from being shifted to the advance side from the specified position (i.e., the intermediate position) as being urged by the advance-restraining urge spring and the retard-restraining lock bar restrains the lock cam (i.e., the vane rotor) from being shifted to the retard side from the specified position (i.e., the intermediate position) as being urged by the retard-restraining urge spring. Accordingly, the vane rotor is surely located at the specified position (i.e., the intermediate position). On the other hand, when fluid pressure is applied to the advance-restraining lock bar or the retard-restraining lock bar via the advance-restraining communication passage or the retard-restraining communication passage, the locking due to the advance-restraining lock bar or the retard-restraining lock bar is released so as not to disturb advancing operation or retarding operation.

[0013] In the above structure, it is also possible that the lock bar is supported as being swingable in a plane perpendicular to the axis line of the cam shaft.
Accordingly, in an engine stopped state, for example, even when the lock bars (i.e., the advance-restraining lock bar and the retard-restraining lock bar) are in a state of being deviated from respective positions to lock the lock cam, the lock bars are rotated in the urged direction owing to torque fluctuation etc. of the cam shaft at the time of engine starting (i.e., at the time of cranking). Accordingly, the lock cam (i.e., the vane rotor) can be surely locked at the specified position (i.e., the intermediate position).

[0014] In the above structure, it is also possible that the lock bar is formed so that the barycenter thereof is located on a line connecting the swing center thereof and the axis line of the cam shaft or at the vicinity of the line in a locked state as being engaged with the lock cam to generate centrifugal force in a direction to maintain the locked state and is located at a position deviated from the line in a lock-released state as being disengaged from the lock cam owing to fluid pressure to generate centrifugal force in a direction to maintain the lock-released state.
According to the structure, when the lock bar is in the locked state as being engaged with the lock cam, the locked state is to be maintained owing to urging force without receiving centrifugal force due to rotation or owing to the urging force and centrifugal force due to the rotation. On the other hand, when the lock bar is in the lock-released state as being disengaged from the lock cam owing to fluid pressure, the lock-released state is surely maintained with centrifugal force due to the rotation exerted in addition to the fluid pressure.

Effects of the Invention

[0015] According to the valve timing changing device having the above structure, with phase control of a vane rotor (i.e., phase changing in a phase adjustment angle range between the most-advanced position and the most-retarded position), engine startability can be improved and rattling etc. at the time of engine starting can be prevented while achieving structural simplification, reduction of part count, miniaturization of the entire device and the like. In addition, the phase adjustment angle can be set wider, so that phase control can be performed widely in accordance with engine drive conditions

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] 

FIG. 1 is an exploded perspective view illustrating an embodiment of a valve timing changing device according to the present invention.

FIG. 2 is a sectional view illustrating the inside of the valve timing changing device according to the present invention.

FIG. 3 is a sectional view illustrating an advancing passage which is communicated with an advancing chamber in a state that a vane rotor constituting a part of the valve timing changing device is at a specified intermediate position in a range of a phase adjustment angle.

FIG. 4 is a sectional view illustrating a retarding passage which is communicated with a retarding chamber in a state that the vane rotor constituting a part of the valve timing changing device is at the specified intermediate position in the range of the phase adjustment angle.

FIG. 5 is a sectional view illustrating a state that the vane rotor is locked at the intermediate position by a lock mechanism (i.e., a lock cam and a lock bar) constituting a part of the valve timing changing device.

FIG. 6 is a sectional view illustrating a state that the vane rotor is located at the most-retarded position as releasing the locking of the vane rotor due to the lock mechanism (i.e., the lock cam and the lock bar) constituting a part of the valve timing changing device.

FIG. 7 is a sectional view illustrating a state that the vane rotor is located at the most-advanced position as releasing the locking of the vane rotor due to the lock mechanism (i.e., the lock cam and the lock bar) constituting a part of the valve timing changing device.

FIG. 8 is a perspective view illustrating a lock bar which constitutes a part of the lock mechanism.

FIG. 9 is a schematic view of the valve timing changing device at the time of engine starting.

FIG. 10 is an explanatory schematic view illustrating operation of the valve timing changing device when the phase is to be changed to the retard side after engine starting.

FIG. 11 is an explanatory schematic view illustrating operation of the valve timing changing device when the phase is to be changed to the advance side after engine starting.

FIG. 12 is an explanatory schematic view illustrating operation of the valve timing changing device when the phase is to be maintained at a specified phase angle.

FIG. 13 is a sectional view illustrating another embodiment of the lock mechanism constituting a part of the valve timing changing device according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] In the following, embodiments of the present invention will be described with reference to the attached drawings.
As illustrated in FIGS. 1 and 2, the valve timing changing device is provided with a vane rotor 20 which is capable of being fixed to a cam shaft 10 in a detachably attachable manner, a housing rotor 30 (i.e., a housing member 31, a sprocket member 32 and a cover member 33) which accommodates the vane rotor 20 in a relatively rotatable manner as being rotated on an axis line S1 of the cam shaft 10 and which defines an advancing chamber 30a and a retarding chamber 30b in cooperation with the vane rotor 20, a lock cam 40 which is fixed to the vane rotor 20, an advance-restraining lock bar 50 and an advance-restraining urge spring 51 which are disposed to the housing rotor 30 to restrain the vane rotor 20 (i.e., the lock cam 40) from being shifted to the advance side, a retard-restraining lock bar 60 and a retard-restraining urge spring 61 which are disposed to the housing rotor 30 to restrain the vane rotor 20 (i.e. the lock cam 40) to the retard side, a center bolt 70 which fastens the vane rotor 20 to the cam shaft 10, an assist mechanism 80 which assists the lock cam 40 to return to a specified position (e.g., an intermediate position), an operating oil control system 100 which includes operating oil passages and an operating oil control valve (OCV) 103 as a fluid control valve which controls flow of operating oil (i.e., engine lubricant oil) as fluid, and the like.

[0018] Here, the cam shaft 10 performs open-close driving of an intake valve or an exhaust valve of an engine with camming action. The housing rotor 30 transmits rotational drive force of a crank shaft to the cam shaft 10 via the vane rotor 20 as being interlocked with rotation of the crank shaft via a chain and the like.
Further, a lock mechanism to lock the vane rotor 20 at the specified position (e.g., the intermediate position) in a predetermined range of an angle (i.e., a phase adjustment angle) as being relatively rotatable against the housing rotor 30 is constituted with the lock cam 40, the advance-restraining lock bar 50, the advance-restraining urge spring 51, the retard-restraining lock bar 60 and the retard-restraining urge spring 61.
Here, in this device, the predetermined angle range (i.e., the angle range from the most-retarded position to the most-advanced position) is set to the order of 35 degrees to 40 degrees, and then, the specified position (i.e., the intermediate position) is set to an angle position as being rotated approximately by 10 degrees from the most-retarded position to the advance side.

[0019] The cam shaft 10 is supported by a bearing B formed at a cylinder head of the engine being rotatable about an axis line S1 (in FIG. 1, as being rotated in a direction of arrow CR). As illustrated in FIGS. 1 and 2, the cam shaft 10 includes a journal portion 11 which is supported by the bearing B, a cylinder portion 12 which rotatably supports the housing rotor 30, an advancing passage 13 and a retarding passage 14 through which operating oil is passed as being formed at the inside of the cam shaft 10, an internal thread portion 15 which fastens the center bolt 70, and the like.

[0020] The advancing passage 13 is formed to be communicated with the advancing chamber 30a so that operating oil is introduced to or discharged from the advancing chamber 30a in accordance with control of the operating oil control valve 103.
The retarding passage 14 is formed to be communicated with the retarding chamber 30b so that operating oil is introduced to or discharged from the retarding chamber 30b in accordance with control of the operating oil control valve 103.

[0021] As illustrated in FIGS. 1 to 4, the vane rotor 20 includes four vane portions 21, a hub portion 22 which integrally holds the four vane portions 21 spaced at regular intervals, an penetration hole 23 through which the center bolt 70 passes as being formed at the hub portion 22, an advancing passage 24 which is communicated with the advancing chamber 30a, a retarding passage 25 which is communicated with the retarding chamber 30b, four groove portions 26 to which a seal member S is respectively fitted as being formed at each distal end of the vane portion 21, and the like.
Then, as illustrated in FIG. 2, the vane rotor 20 is fastened to the cam shaft 10 along with the lock cam 40 by utilizing the center bolt 70 so as to be rotated integrally with the cam shaft 10.

[0022] The housing rotor 30 is supported rotatably on the axis line S1 of the cam shaft 10 as being interlocked with rotation of the crank shaft. As illustrated in FIG. 1, the housing rotor 30 is constituted with the housing member 31, the sprocket member 32 as being joined at a back face side of the housing member 31, and the cover member 33 as being connected to a front face side of the housing member 31. The housing rotor 30 is formed to define an accommodation room A1 which accommodates the vane rotor 20 in a relatively rotatable manner in the predetermined range of the angle (i.e. the phase adjustment angle) and an isolation room A2 which accommodates the lock mechanism (40, 50, 51, 60 and 61) as being isolated from the accommodation room A1. Here, the accommodation room A1 is separated into the advancing chambers 30a and the retarding chambers 30b by the vane rotor 20 (i.e., the vane portions 21 thereof).

[0023] As illustrated in FIGS. 1 to 4, the housing member 31 includes a cylinder wall 31a, an isolation wall 31b, a penetration hole 31c formed at the center of the isolation wall 31b, four bearing portions 31d protruded toward the center at a back face side of the isolation wall 31b, a concave portion 31e which accommodates the vane rotor 20 as being defined at a center part and between the respective bearing portions 31d, a concave portion 31f which accommodate the lock mechanism as being formed at a front face side of the isolation wall 31b, an advance-restraining communication passage 31g which is disposed to the isolation wall 31b to be communicated with the advancing chamber 30a, a retard-restraining communication passage 31h which is disposed to the isolation wall 31b to be communicated with the retarding chamber 30b, support shafts 31i, 31j, engagement projections 31k, 31m, a stopper wall 31n which defines the most-retarded position, a stopper wall 31o which defines the most-advanced position, a stopper wall 31p to which the advance-restraining lock bar 50 is possibly contacted, a stopper wall 31q to which the retard-restraining lock bar 60 is possibly contacted, a concave portion 31r which accommodates the assist mechanism 80, screw holes 31s for fastening the cover member 33 and the sprocket member 32 by utilizing bolts, and the like.

[0024] The isolation wall 31b is formed to isolate the accommodation room A1 from the isolation room A2 so that the lock mechanism (40, 50, 51, 60 and 61) is arranged to be isolated from the vane rotors 20.
The penetration hole 31c is formed in shape and size to ensure a sealing ability (i.e., to prevent leakage of operating oil) owing to intimate contact between the back face of the isolation wall 31b and a front face of the vane rotor 20 (i.e., the hub portion 22 thereof) while allowing integral connection of a back face of the lock cam 40 with the front face of the hub portion 22 of the vane rotor 20 by the center bolt 70.
The concave portion 31e functions as the accommodation room A1 when the sprocket member 32 is joined in a state that the vane rotor 20 is assembled as being rotatable in the predetermined angle range (i.e., an operating angle range).

[0025] As illustrated in FIGS. 5 to 7, the concave portion 31f is formed to accommodate respectively the lock cam 40 as being rotatable about the axis line S1, the advance-restraining lock bar 50 as being swingable about an axis line S2, the advance-restraining urge spring 51 as being extendable, the retard-restraining lock bar 60 as being swingable about an axis line S3, and the retard-restraining urge spring 61 as being extendable.
Further, the concave portion 31f is formed so that oil pressure at a predetermined level or higher can be obtained in cooperation with a side face of the advance-restraining lock bar 50 as being filled with operating oil which is guided from the advance-restraining communication passage 31g and so that oil pressure at a predetermined level or higher can be obtained in cooperation with a side face of the retard-restraining lock bar 60 as being filled with operating oil which is introduced from the retard-restraining communication passage 31h.
Then, the concave portion 31f functions as the isolation room A2 when the cover member 33 is joined in a state that the lock mechanism (40, 50, 51, 60 and 61) is assembled.
Accordingly, since the isolation roomA2 in which the lock mechanism is arranged is defined by the isolation wall 31b of the housing member 31 and the cover member 33 which is detachably attachable to the housing member 31, assembling operation and disassembling operation of the lock mechanism can be easily performed in a state that the vane rotor 20 is assembled in the accommodation room A1 of the housing member 31.

[0026] The advance-restraining communication passage 31g is formed to introduce oil pressure to the side face of the advance-restraining lock bar 50 as being communicated with the advancing chamber 30a so that locking due to the advance-restraining lock bar 50 is released against urging force of the advance-restraining urge spring 51.
The retard-restraining communication passage 31h is formed to introduce oil pressure to the side face of the retard-restraining lock bar 60 as being communicated with the retarding chamber 30b so that locking due to the retard-restraining lock bar 60 is released against urging force of the retard-restraining urge spring 61.

[0027] As illustrated in FIGS. 5 to 7, the support shaft 31i is formed to support the advance-restraining lock bar 50 as being swingable in a plane perpendicular to the axis line S2.
As illustrated in FIGS. 5 to 7, the support shaft 31j is formed to support the retard-restraining lock bar 60 as being swingable in a plane perpendicular to the axis line S3.
As illustrated in FIGS. 5 to 7, the engagement projection 31k is formed to be engaged with one end of the advance-restraining urge spring 51.
As illustrated in FIGS. 5 to 7, the engagement projection 31m is formed to be engaged with one end of the retard-restraining urge spring 61.
As illustrated in FIG. 6, the stopper wall 31n defines the most-retarded position as being contacted with a projection 41 of the lock cam 40 in the predetermined angle range of relative rotation of the vane rotor 20 against the housing rotor 30.
As illustrated in FIG. 7, the stopper wall 31o defines the most-advanced position as being contacted with the projection 41 of the lock cam 40 in the predetermined angle range of relative rotation of the vane rotor 20 against the housing rotor 30.
As illustrated in FIGS. 5 and 6, the stopper wall 31p defines a rest position to possibly lock the lock cam 40 as the advance-restraining lock bar 50 being rotationally urged with urging force of the advance-restraining urge spring 51 in a state that oil pressure of operating oil is not applied.
As illustrated in FIGS. 5 and 7, the stopper wall 31q defines a rest position to possibly lock the lock cam 40 as the retard-restraining lock bar 60 being rotationally urged with urging force of the retard-restraining urge spring 61 in a state that oil pressure of operating oil is not applied.

[0028] As illustrated in FIGS. 1 and 2, the sprocket member 32 includes a sprocket 32a around which a chain for transmitting rotational drive force of the crank shaft is wound, an inner circumferential face 32b which is rotatably fitted to the cylinder portion 12 of the cam shaft 10, a front face 32c to which a back face of the vane rotor 20 is slidably contacted, screw holes 32d for being joined to the housing member 31 by utilizing the bolts, and the like.
Here, the sprocket member 32 defines the accommodation room A1 in cooperation with the front face 32c thereof and the concave portion 31e by being joined to the housing member 31 in which the vane rotor 20 is accommodated by utilizing the bolts.

[0029] As illustrated in FIGS. 1 and 2, the cover member 33 is formed in a detachably attachable manner to the housing member 31 as including a circular hole 33a through which the center bolt 70 is passed, a back face 33b, screw holes 33c for being fastened to the housing member 31by utilizing the bolts, and the like.
Here, by being joined to the housing member 31 by utilizing the bolts etc., the cover member 33 defines the isolation room A2 in cooperation with the back face 33b thereof and the concave portion 31f while sealing is performed not to generate leakage of operating oil as covering from the front side in a state that the lock mechanism (i.e., the lock cam 40, the advance-restraining lock bar 50, the advance-restraining urge spring 51, the retard-restraining lock bar 60 and the retard-restraining urge spring 61) is accommodated in the concave portion 31f.

[0030] As illustrated in FIGS. 1, 2 and 5 to 7, the lock cam 40 is to be rotated integrally with the vane rotor 20 and the cam shaft 10 as being fastened to the cam shaft 10 along with the vane rotor 20 by the center bolt 70. The lock cam 40 includes the projection 41 which is possibly contacted to a push rod 81 of the assist mechanism 80 as well as the stopper walls 31n, 31o, a cam face 42 which is possibly engaged with and disengaged from the advance-restraining lock bar 50, a cam face 43 which is possibly engaged with and disengaged from the retard-restraining lock bar 60, and a penetration hole 44 through which the center bolt 70 is passed.
The cam face 42 is formed so that rotation toward the advance side is restrained with contact of the advance-restraining lock bar 50 when the vane rotor 20 is at the intermediate position.
The cam face 43 is formed so that rotation toward the retard side is restrained with contact of the retard-restraining lock bar 60 when the vane rotor 20 is at the intermediate position.
The lock cam 40 is fixed to the cam shaft 10 so as to be located at the intermediate position as being locked by the advance-restraining lock bar 50 and the retard-restraining lock bar 60 in a state as illustrated in FIG. 5, to define the most-retarded position in a state that the projection 41 is contacted to the stopper wall 31n as illustrated in FIG. 6, and to define the most-advanced position in a state that the projection 41 is contacted to the stopper wall 31o as illustrated in FIG. 7.

[0031] As illustrated in FIGS. 5 to 7, the advance-restraining lock bar 50 is swingable about the axis line S2 in the plane perpendicular to the axis line S1 as being supported by the support shaft 31i of the housing member 31 and is rotationally urged counterclockwise to be contacted to the stopper wall 31p as the other end of the advance-restraining urge spring 51 being engaged therewith.
Then, the advance-restraining lock bar 50 restrains the lock cam 40 (i.e., the vane rotor 20) from being rotated to the advance side from the rest position as contacting the cam face 42 of the lock cam 40 in a state that counterclockwise rotation thereof is restrained owing to contact with the stopper wall 31p. On the contrary, the locking thereof is released as being rotated clockwise owing to oil pressure of operating oil supplied through the advance-restraining communication passage 31g.
Here, the advance-restraining lock bar 50 is formed as follows. That is, in a state of a locked state as being engaged with the lock cam 40, the barycenter G1 thereof is located on a line L1 connecting the swing center S2 thereof and the axis line S1 of the cam shaft or at the vicinity of the line L1 (i.e., at a position deviated to the clockwise side from the line L1) so as to generate centrifugal force in a direction to maintain the locked state, as illustrated in FIG. 5. Meanwhile, in a state of a lock-released state as being disengaged from the lock cam 40 owing to oil pressure of operating oil, the barycenter G1 is located at a position deviated (to the counterclockwise side) against the line L1 so as to generate centrifugal force in a direction to maintain the lock-released state, as illustrated in FIG. 7.
As a method to locate the barycenter G1 to be closer to the swing center S2, the advance-restraining lock bar 50 is formed so that thickness of a portion 50a at the swing center side is larger than the thickness of a portion 50b at a distal end side, for example, as illustrated in FIG. 8 when material having constant density is adopted.
With the above configuration, when the advance-restraining lock bar 50 is in the locked state as being engaged with the lock cam 40, the locked state is to be maintained owing to urging force of the advance-restraining urge spring 51 without receiving centrifugal force due to rotation or owing to the urging force and centrifugal force due to the rotation. On the other hand, when the advance-restraining lock bar 50 is in the lock-released state as being disengaged from the lock cam 40 owing to oil pressure of operating oil, the lock-released state is surely maintained with centrifugal force due to the rotation exerted in addition to the oil pressure of operating oil.

[0032] As illustrated in FIGS. 5 to 7, the retard-restraining lock bar 60 is swingable about the axis line S3 in the plane perpendicular to the axis line S1 as being supported by the support shaft 31j of the housing member 31 and is rotationally urged clockwise to be contacted to the stopper wall 31q as the other end of the retard-restraining urge spring 61 being engaged therewith.
Then, the retard-restraining lock bar 60 restrains the lock cam 40 (i.e., the vane rotor 20) from being rotated to the retard side from the rest position as contacting the cam face 43 of the lock cam 40 in a state that clockwise rotation thereof is restrained owing to contact with the stopper wall 31q. On the contrary, the locking thereof is released as being rotated counterclockwise owing to oil pressure of operating oil supplied through the retard-restraining communication passage 31h.
Here, the retard-restraining lock bar 60 is formed as follows. That is, in a locked state as being engaged with the lock cam 40, the barycenter G2 thereof is located on a line L2 connecting the swing center S3 thereof and the axis line S1 of the cam shaft or at the vicinity of the line L2 (i.e., at a position deviated to the counterclockwise side from the line L2) so as to generate centrifugal force in a direction to maintain the locked state, as illustrated in FIG. 5. Meanwhile, in a state of a lock-released state as being disengaged from the lock cam 40 owing to oil pressure of operating oil, the barycenter G2 is located at a position deviated (to the clockwise side) from the line L2 so as to generate centrifugal force in a direction to maintain the lock-released state, as illustrated in FIG. 6.
As a method to locate the barycenter G2 to be closer to the swing center S3, the retard-restraining lock bar 60 is formed so that thickness of a portion 60a at the swing center side is larger than the thickness of a portion 60b at a distal end side, for example, as illustrated in FIG. 8 when material having constant density is adopted.
With the above configuration, when the retard-restraining lock bar 60 is in the locked state as being engaged with the lock cam 40, the locked state is to be maintained owing to urging force of the retard-restraining urge spring 61 without receiving centrifugal force due to rotation or owing to the urging force and centrifugal force due to the rotation. On the other hand, when the retard-restraining lock bar 60 is in the lock-released state as being disengaged from the lock cam 40 owing to oil pressure of operating oil, the lock-released state is surely maintained with centrifugal force due to the rotation exerted in addition to the oil pressure of operating oil.

[0033] In this manner, the lock bars (i.e., the advance-restraining lock bar 50 and the retard-restraining lock bar 60) are supported as being swingable in the plane perpendicular to the axis line S1 of the cam shaft 10. Therefore, even in a case that the lock bars (i.e., the advance-restraining lock bar 50 and the retard-restraining lock bar 60) are in a state of being deviated from respective positions to lock the lock cam 40 when the engine is stopped, the lock bars (i.e., the advance-restraining lock bar 50 and the retard-restraining lock bar 60) are rotated in the urged direction owing to torque fluctuation etc. of the cam shaft 10 at the time of engine starting (i.e., at the time of cranking). Accordingly, the lock cam 40 (i.e., the vane rotor 20) can be surely moved to the intermediate position to be locked.
Further, as described above, the lock mechanism (40, 50, 51, 60 and 61) is arranged in the isolation room A2 isolated from the accommodation room A1 which accommodates the vane rotor 20. Here, since the vane rotor 20 is not directly locked, the vane portions 21 of the vane rotor 20 can be thinned and design flexibility and layout flexibility can be increased. Further, since volume for arranging the lock mechanism becomes unnecessary at the side of accommodation room A1 which accommodates the vane rotor 20, the phase adjustment angle between the most-advanced position and the most-retarded position can be set wider by the amount of the volume. Accordingly, it is possible to perform phase control widely if required.
In particular, when a vane accommodating pin for locking is maintained at an intermediate position in an accommodation room at the time of starting as in the related art, a sufficient control angle for phase adjustment cannot be ensured to the advance side from the position at the time of starting. On the contrary, in the present invention, since extra thickness is not required for a vane, the angle of phase control (i.e., the phase adjustment angle) can be sufficiently ensured. In particular, it is possible to ensure the angle of phase control (i.e., the phase adjustment angle) to the advance side from the starting.

[0034] As illustrated in FIGS. 1 and 2, the center bolt 70 fastens the lock cam 40 and the vane rotor 29 to the cam shaft 10. The center bolt 70 includes an external thread portion 72 which is screwed with the internal thread portion 15 of the cam shaft 10, a retarding passage 71 which causes communication between the retarding passage 14 and the retarding chamber 30b to supply operating oil to the retarding chamber 30b or to discharge operating oil from the retarding chamber 30b, and the like as being at the inside of the cam shaft 10.

[0035] The assist mechanism 80 exerts assist force to move the lock cam 40 (i.e., the vane rotor 20 and the cam shaft 10) from the most-retarded position to the intermediate position. As illustrated in FIG. 1, the assist mechanism 80 is constituted with the push rod 81 which is accommodated in the concave portion 31r of the housing member 31 and an urge spring 82 which urges the push rod 81 to be protruded into the isolation room A2.
The push rod 81 is urged by the urge spring 82 so that the distal end thereof is protruded and contacted to one side face of the projection 41 of the lock cam 40 for locating the lock cam 40 at the intermediate position by urging from the retard side to the advance side.

[0036] As illustrated in FIG. 2, the operating oil control system 100 includes a pump 101 to feed operating oil, a drain passage 102, the operating oil control valve (OCV) 103, an advancing passage 104, a retarding passage 105, and the like.
As illustrated in FIG. 2, the operating oil control valve 103 includes a DD port 103a which discharges operating oil from the advancing passage 104 and the retarding passage 105, a DP port 103b which discharges operating oil from the advancing passage 104 and supplies operating oil to the retarding passage 105, a CC port 103c which blocks the advancing passage 104 and the retarding passage 105, and a PD port 103d which supplies operating oil to the advancing passage 104 and discharges operating oil from the retarding passage 105.
In the operating oil control valve 103, the DD port 103a is selected owing to urging force of a spring in a non-powered rest state, and then, the DP port 103b, the CC port 103c or the PD port 103d is selected by appropriately controlling electromagnetic drive force.
The advancing passage 104 and the retarding passage 105 are defined by operating oil passages (i.e., lubricant passages) formed in a cylinder block or a cylinder head of the engine or pipes etc. for operating oil passages arranged at the outside of the engine.

[0037] Next, operation of the valve timing changing device will be described with reference to FIGS. 5 to 7 and 9 to 12.
When the engine is stopped, the DD port 103a is selected in the operating oil control valve 103 and the advancing chamber 30a and the retarding chamber 30b are in a state that operating oil is discharged respectively through the advancing passage 104 and the retarding passage 105, as illustrated in FIG. 9.
Further, as illustrated in FIG. 5, the advance-restraining lock bar 50 and the retard-restraining lock bar 60 are in a state of locking the lock cam 40 (i.e., the locked state) and the push rod 81 of the assist mechanism 80 is in a state of being contacted to the projection 41. Therefore, the vane rotor 20 is located at the intermediate position in the predetermined angle range as illustrated in FIGS. 3 and 4.
The intermediate position is set for the valve timing at which smooth starting can be performed. Accordingly, when starting (i.e., cranking) of the engine is initiated in the above state, the engine can be smoothly started.
In this manner, since the vane rotor 20 (i.e., the cam shaft 10) is to be located at the intermediate position owing to the lock mechanism at the time of engine starting (i.e., cranking), the engine can be smoothly started without unnecessary load while preventing occurrence of rattling. In addition, even after starting (i.e., complete combustion) of the engine, phase control can be smoothly performed while preventing unnecessary load.

[0038] Here, at the time of stopping of the engine, in a case that the lock cam 40 receives only the assist force from the assist mechanism 80 without being locked by the advance-restraining lock bar 50 and the retard-restraining lock bar 60, the vane rotor 20 is to be stopped at an arbitrary position between the intermediate position and the most-advanced position. Alternatively, in a case that the assist force due to the assist mechanism 80 is not exerted as well without being locked by the advance-restraining lock bar 50 and the retard-restraining lock bar 60, the vane rotor 20 is to be stopped at an arbitrary position between the most-retarded position and the most-advanced position.
In the above state, the vane rotor 20 is relatively rotatable against the housing rotor 30. Accordingly, when starting (i.e., cranking) of the engine is initiated, the advance-restraining lock bar 50 and the retard-restraining lock bar 60 operate to immediately lock the lock cam 40 at the intermediate position owing to torque fluctuation of the cam shaft 10, the advance-restraining urge spring 51, the retard-restraining urge spring 61 and the like.
Accordingly, the vane rotor 20 is immediately located at the intermediate position and smooth starting (i.e. complete combustion) of the engine can be performed while preventing occurrence of rattling.

[0039] As illustrated in FIGS. 10 to 12, when starting (i.e., the complete combustion) of the engine is performed, phase control is performed with appropriate switching of the operating oil control valve 103 so that the vane rotor 20 (i.e., the cam shaft 10) is moved from the intermediate position to the advance side or the retard side and is further maintained at a specified angle position.
For example, when the phase is to be changed from the intermediate position to the retard side, the DP port 103b is selected with switching of the operating oil control valve 103, as illustrated in FIG. 10. Accordingly, operating oil is supplied to the retarding chamber 30b through the retarding passage 105 and oil pressure of the operating oil is supplied to the retard-restraining lock bar 60 from the retarding chamber 30b through the retard-restraining communication passage 31h. Meanwhile, operating oil is discharged from the advancing chamber 30a through the advancing passage 104.
Then, as illustrated in FIG. 6, the retard-restraining lock bar 60 is to be disengaged from the lock cam 40 owing to oil pressure of operating oil supplied through the retard-restraining communication passage 31h and the locking is released. Accordingly, the phase can be changed by moving the vane rotor 20 to the retard side.

[0040] On the contrary, when the phase is to be changed to the advance side, the PD port 103d is selected with switching of the operating oil control valve 103, as illustrated in FIG. 11. Accordingly, operating oil is supplied to the advancing chamber 30a through the advancing passage 104 and oil pressure of the operating oil is supplied to the advance-restraining lock bar 50 from the advancing chamber 30a through the advance-restraining communication passage 31g. Meanwhile, operating oil is discharged from the retarding chamber 30b through the retarding passage 105.
Then, as illustrated in FIG. 7, the advance-restraining lock bar 50 is to be disengaged from the lock cam 40 owing to oil pressure of operating oil supplied through the advance-restraining communication passage 31g and the locking is released. Accordingly, the phase can be changed by moving the vane rotor 20 to the advance side.

[0041] Further, the vane rotor 20 is to be maintained at a specified angle position, the CC port 103c is selected with switching of the operating oil control valve 103, as illustrated in FIG. 12. Accordingly, both of the advancing passage 104 and the retarding passage 105 are blocked and oil pressure of the operating oil in the advancing chamber 30a and the retarding chamber 30b is maintained without change.
In this manner, the vane rotor 20 can be maintained at the specified angle while the advance-restraining lock bar 50, the retard-restraining lock bar 60 and the lock cam 40 are maintained in the state at that time.

[0042] As described above, according to the valve timing changing device, the lock mechanism is arranged in the isolation room A2 isolated from the accommodation room A1 which accommodates the vane rotor 20. Therefore, compared to a traditional device with a lock mechanism being protruded and retracted against a slide boundary face in an accommodation room which accommodates a vane rotor, volume for arranging the lock mechanism becomes unnecessary and the phase adjustment angle between the most-advanced position and the most-retarded position can be set wider by the amount of the volume. Accordingly, it is possible to perform phase control widely if required.
In particular, when a thick vane accommodating a pin for locking is to be maintained at an intermediate position in the accommodation room at the time of starting as in the related art, a sufficient control angle for phase adjustment from the starting position to the advance side cannot be ensured. On the contrary, in the present invention, since extra thickness is not required for the vane, the angle of phase control (i.e., the phase adjustment angle) can be sufficiently ensured. In particular, it is possible to sufficiently ensure the angle required for performing phase control (i.e., the phase adjustment angle) to the advance side from the starting.

[0043] FIG. 13 illustrates another embodiment of a lock mechanism which constitutes a part of the valve timing changing device according to the present invention.
In the present embodiment, an advance-restraining lock bar 50', a retard-restraining lock bar 60', an advance-restraining urge spring 51' and a retard-restraining urge spring 61' are adopted instead of the advance-restraining lock bar 50, the retard-restraining lock bar 60, the advance-restraining urge spring 51 and the retard-restraining urge spring 61 of the abovementioned embodiment.
As illustrated in FIG. 13, the advance-restraining lock bar 50' includes a spring engaging portion 50c' at a distal end side being apart from the swing center S2.
As illustrated in FIG. 13, the advance-restraining urge spring 51' being a compression type coil spring exerts urging force to press the advance-restraining lock bar 50' to the lock cam 40 (i.e., the cam face 42 thereof) as being engaged with the distal end side (i.e., the spring engaging portion 50c') of the advance-restraining lock bar 50' in a state of being compressed by a specified compression amount.
As illustrated in FIG. 13, the retard-restraining lock bar 60' includes a spring engaging portion 60c' at a distal end side being apart from the swing center S3.
As illustrated in FIG. 13, the retard-restraining urge spring 61' being a compression type coil spring exerts urging force to press the retard-restraining lock bar 60' to the lock cam 40 (i.e., the cam face 43 thereof) as being engaged with the distal end side (i.e., the spring engaging portion 60c') of the retard-restraining lock bar 60' in a state of being compressed by a specified compression amount.
In the present embodiment, since the urging force of the spring (i.e., the advance-restraining urge spring 51' and the retard-restraining urge spring 61') is exerted to a free end side of the lock bar (the advance-restraining lock bar 50' and the retard-restraining lock bar 60' , rotation torque around the swing center S2, S3 due to the urging force becomes large. Accordingly, the spring (i.e., the advance-restraining urge spring 51' and the retard-restraining urge spring 61') can be downsized so as to contribute to miniaturization, weight reduction and simplification of the device.

[0044] In the above description of the embodiments, the housing rotor 30 includes the sprocket 32a which transmits rotational drive force of the crank shaft. However, not limited to the above, when means to transmit rotational drive force of the crank shaft has another structure (e.g., a toothed timing belt), a housing rotor with a component (e.g., a toothed pulley) structured as being matched thereto can be adopted.
Further, in the above description of the embodiments, the lock mechanism is constituted with the lock cam 40, the advance-restraining lock bar 50, 50', the advance-restraining urge spring 51, 51', the retard-restraining lock bar 60, 60', and the retard-restraining urge spring 61, 61'. However, not limited to the above, a lock cam may be formed integrally with a vane rotor as long as a lock mechanism is arranged in the isolation room A2 which is isolated from the accommodation room A1. Further, it is also possible to adopt a structure that an advance-restraining lock bar and a retard-restraint lock bar are urged to a rest position (i.e., a position at which the lock cam 40 is locked) owing to own urging force respectively as eliminating the advance-restraining urge spring 51, 51' and the retard-restraining urge spring 61, 61'.
Further, in the above description of the embodiments, the advance-restraining communication passage 31g and the retard-restraining communication passage 31h are communicated respectively with the advancing chamber 30a and the retarding chamber 30b. However, not limited to the above, it is also possible to be communicated respectively with an advancing passage and a retarding passage.
Further, in the above description of the embodiments, the advance-restraining lock bar 50, 50' and the retard-restraining lock bar 60, 60' are adopted as the lock bars. However, not limited to the above, lock bars may be structured in different numbers and shapes.
Furthermore, in the above description of the embodiments, the intermediate position in a specified angle range is adopted as a specified position at which the vane rotor is locked by the lock mechanism. However, not limited to the above, any desired position may be adopted in accordance with engine characteristics such as being locked at the most-retarded position and being locked at the most-advanced position.

INDUSTRIAL APPLICABILITY

[0045] As described above, with phase control of a vane rotor (i.e., phase changing in a phase adjustment angle range between the most-advanced position and the most-retarded position), the valve timing changing device of the present invention improves engine startability while achieving structural simplification, reduction of part count, miniaturization of the entire device, and the like. In addition, rattling etc. at the time of engine starting can be prevented and the phase adjustment angle can be set wider. Accordingly, since phase control can be performed widely in accordance with engine drive conditions, the valve timing changing device of the present invention is useful for a small engine etc. mounted on a motorcycle etc. as well as being adoptable for an internal combustion engine mounted on an automobile etc.

DESCRIPTION OF NUMERALS

[0046] 

B

Bearing

CR

Rotation direction of cam shaft

10

Cam shaft

S1

Axis line

11

Journal portion

12

Cylinder portion

13

Advancing passage

14

Retarding passage

15

Internal thread portion

20

Vane rotor

21

Vane portion

22

Hub portion

23

Penetration hole

24

Advancing passage

25

Retarding passage

26

Groove portion

S

Seal member

30

Housing rotor

30a

Advancing chamber

30b

Retarding chamber

A1

Accommodation room

A2

Isolation room

31

Housing member

31a

Cylinder wall

31b

Isolation wall

31c

Penetration hole

31d

Bearing portion

31e

Concave portion

31f

Concave portion

31g

Advance-restraining communication passage

31h

Retard-restraining communication passage

31i, 31j

Support shaft

S2, S3

Axis line

31k, 31m

Engagement projection

31n, 31o, 31p, 31q

Stopper wall

31r

Concave portion

31s

Screw hole

32

Sprocket member

32a

Sprocket

32b

Inner circumferential face

32c

Front face

32d

Screw hole

33

Cover member

33a

Circular hole

33b

Back face

33c

Screw hole

40

Lock cam

41

Projection

42, 43

Cam face

50, 50'

Advance-restraining lock bar (Lock mechanism)

L1

Line

G1

Barycenter

51, 51'

Advance-restraining urge spring (Lock mechanism)

60, 60'

Retard-restraining lock bar (Lock mechanism)

L2

Line

G2

Barycenter

61, 61'

Retard-restraining urge spring (Lock mechanism)

70

Center bolt

71

Retarding passage

72

External thread portion

80

Assist mechanism

81

Push rod

82

Urge spring

100

Operating oil control system

101

Pump

102

Drain passage

103

Operating oil control valve (Fluid control valve)

103a

DD port

103b

DP port

103c

CC port

103d

PD port

104

Advancing passage

105

Retarding passage

Claims

1. A valve timing changing device to change open-close timing of an intake valve or an exhaust valve of which open-close driving is performed by a cam shaft (10), comprising:

a housing rotor (30) which is rotated on an axis line (S1) of a cam shaft (10) as being interlocked with rotation of a crank shaft;

a vane rotor (20) which is accommodated in an accommodation room (A1) of the housing rotor (30) as being relatively rotatable in a predetermined angle range while separating the accommodation room (A1) into a advancing chamber (30a) and a retarding chamber (30b) and which is rotated integrally with the cam shaft (10);

an advancing passage (13) which passes fluid as being communicated with the advancing chamber (30a);

a retarding passage (14) which passes fluid as being communicated with the retarding chamber (30b); and

a lock mechanism (40, 50, 51, 60, 61) which locks the vane rotor (20) against the housing rotor (30) at a specified position in the predetermined angle range;

wherein the housing rotor (30) is formed to define an isolation room (A2) isolated from the accommodation room (A1) which accommodates the vane rotor (20); and

the lock mechanism (40, 50, 51, 60, 61) is arranged in the isolation room (A2);

wherein the housing rotor (30) includes a housing member (31) having an isolation wall (31b) which isolates the isolation room (A2) from the accommodation room (A1), and a cover member (33) formed as being detachably attachable to the housing member (31) to define the isolation room (A2) in cooperation with the isolation wall (31b);

characterized in that:

the lock mechanism (40, 50, 51, 60, 61) locks the vane rotor (20) at the specified intermediate position in the predetermined angle range at the time of engine starting;

wherein the lock mechanism (40, 50, 51, 60, 61) includes a lock cam (40) connected to the vane rotor (20) via a penetration hole which is formed at the isolation wall (31 b) to be integrally rotated, and a lock bar (50, 60) which is movably arranged against the housing rotor (30) and which is capable of being locked as being engaged with the lock cam (40) owing to urging force and releasing the locking owing to fluid pressure.

2. The valve timing changing device according to claim 1, further comprising an urge spring (51, 61) which exerts urging force to lock the lock bar (50, 60) to be engaged with the lock cam (40),
wherein the lock bar (50, 60) includes an advance-restraining lock bar (50) which is engaged with the lock cam (40) to restrain the vane rotor (20) from being rotated to an advance side, and a retard-restraining lock bar (60) which is engaged with the lock cam (40) to restrain the vane rotor (20) from being rotated to a retard side;
the urge spring (51, 61) includes an advance-restraining urge spring (51) which urges to lock the advance-restraining lock bar (50) as being engaged with the lock cam (40), and a retard-restraining urge spring (61) which urges to lock the retard-restraining lock bar (60) as being engaged with the lock cam (40); and
the housing rotor (30) includes an advance-restraining communication passage (31 g) which guides fluid pressure to the advance-restraining lock bar (50) in the isolation room (A2) to release locking as being communicated with the advancing chamber (30a) or the advancing passage (13), and a retard-restraining communication passage (31h) which guides fluid pressure to the retard-restraining lock bar (60) in the isolation room (A2) to release locking as being communicated with the retarding chamber (30b) or the retarding passage (14).

3. The valve timing changing device according to claim 1 or 2,
wherein the lock bar (50, 60) is supported as being swingable in a plane perpendicular to the axis line (S1).

4. The valve timing changing device according to claim 3,
wherein the lock bar (50, 60) is formed so that the barycenter (G1, G2) thereof is located on a line connecting the swing center (S2, S3) thereof and the axis line (S1) of the cam shaft (10) or at the vicinity of the line in a locked state as being engaged with the lock cam (40) to generate centrifugal force in a direction to maintain the locked state and is located at a position deviated from the line in a lock-released state as being disengaged from the lock cam (40) owing to fluid pressure to generate centrifugal force in a direction to maintain the lock-released state.

Ansprüche

1. Eine Ventiltaktänderungsvorrichtung zum Ändern eines Öffnungs-Schließ-Taktes eines Einlassventils oder eines Auslassventils von welcher das Öffnungs-Schließ-Treiben durch eine Nockenwelle (10) durchgeführt wird, welche aufweist:

einen Gehäuserotor (30), welcher auf einen Achsenlinie (S1) einer Nockenwelle (10) gedreht bzw. rotiert wird, um mit der Rotation einer Kurbelwelle gekuppelt bzw. verriegelt zu sein;

einen Flügelrotor (20), welcher in einem Unterbringungsraum bzw. Gehäuseraum (A1) des Gehäuserotors (30) untergebracht bzw. beherbergt ist, um relativ drehbar in einem vorbestimmten Winkelbereich zu sein, während der Unterbringungsraum bzw. Gehäuseraum (A1) in eine weiterführende Kammer bzw. Vorwärtskammer (30a) und eine rückwärtige Kammer bzw. Verzögerungskammer (30b) separiert bzw. getrennt ist, und welcher integral mit der Nockenwelle (10) gedreht bzw. rotiert wird;

eine weiterführende Passage bzw. Verzögerungspassage (13), welche Fluid passieren lässt, um mit der weiterführenden Kammer bzw. Vorwärtskammer (30a) zu kommunizieren;

eine rückwärtige Passage bzw. Verzögerungspassage (14), welche Fluid passieren lässt, um mit der rückwärtigen Kammer bzw. Verzögerungskammer (30b) zu kommunizieren; und

einen Verschlussmechanismus bzw. Verriegelungsmechanismus (40, 50, 51, 60, 61), welcher den Flügelrotor (20) gegen den Gehäuserotor (30) bei einer spezifizierten Position in dem vorbestimmten Winkelbereich verschließt bzw. verriegelt;

wobei der Gehäuserotor (20) ausgebildet ist, um einen Isolationsraum (A2) zu definieren, der von dem Unterbringungsraum bzw. Gehäuseraum (A1) isoliert ist, welcher den Flügelrotor (20) beinhaltet bzw. beherbergt; und

der Verschlussmechanismus bzw. Verriegelungsmechanismus 40, 50, 51, 60, 61) in dem Isolationsraum (A2) angeordnet ist;

wobei der Gehäuserotor (30) ein Gehäuseglied (31) einschließt, das eine Isolationswand (31b) hat, welche den Isolationsraum (A2) isoliert, und zwar von dem Unterbringungsraum bzw. Gehäuseraum (A1), und ein Abdeckglied (33), das ausgebildet ist, um abnehmbar bzw. entfernbar an das Gehäuseglied (31) angebracht zu werden, um den Isolationsraum (A2) zu definieren, und zwar in Zusammenarbeit bzw. Kooperation mit der Isolationswand (31b);

dadurch gekennzeichnet, dass:

der Verschlussmechanismus bzw. Verriegelungsmechanismus (40, 50, 51, 60, 61) den Flügelrotor (20) bei der spezifizierten Zwischenposition in dem vorbestimmten Winkelbereich zu der Zeit des Maschinenstartens verschließt bzw. verriegelt;

wobei der Verschlussmechanismus bzw. Verriegelungsmechanismus (40, 50, 51, 60, 61) einen Verschlussnocken bzw. Sperrnocken (40), der an den bzw. mit dem Flügelrotor (20) über ein Penetrationsloch bzw. Durchgangsloch verbunden ist, welches in bzw. bei der Isolationswand (31b) ausgebildet ist, um integral gedreht zu werden, und eine Verschlussstange bzw. Verriegelungsstange (50, 60) einschließt, welche bewegbar gegen den Gehäuserotor (30) angeordnet ist, und welche fähig ist, verschlossen bzw. verriegelt zu werden, um mit dem Verschlussnocken bzw. Sperrnocken (40) einzugreifen bzw. einzurasten oder in Eingriff zu sein, und zwar aufgrund der Druckkraft bzw. Antriebskraft und das Verschließen bzw. Verriegeln aufgrund des Fluiddruckes freigegeben bzw. gelöst wird.

2. Ventiltaktänderungsvorrichtung nach Anspruch 1, weiter aufweisend eine Antriebsfeder bzw. Druckfeder (51, 61), welche Antriebskraft bzw. Druckkraft auf die Verschlussstange bzw. Verriegelungsstange (50, 60) ausübt, um mit dem Verschlussnocken bzw. Sperrnocken (40) eingerastet bzw. im Eingriff zu sein,
wobei die Verriegelungsstange (50, 60) eine Vorwärtsbeschränkungsverriegelungsstange (50), welche mit dem Verschlussnocken bzw. Sperrnocken (40) eingerastet bzw. im Eingriff ist, um den Flügelrotor (20) vom rotiert bzw. gedreht sein zurückzuhalten, und zwar auf eine bzw. zu einer Vorwärtsseite bzw. Vorlaufseite, und eine Verzögerungsbeschränkungsverriegelungsstange (60) einschließt, welche mit dem Verschlussnocken bzw. Sperrnocken (40) im Eingriff bzw. eingerastet ist, um den Flügelrotor (20) vom rotiert bzw. gedreht sein zurückzuhalten, und zwar auf eine bzw. zu einer Verzögerungsseite;
die Antriebsfeder bzw. Druckfeder (51, 61) eine Vorwärtsbeschränkungsantriebsfeder (51), welche die Vorwärtsbeschränkungsverriegelungsstange (50) dazu drängt, zu verriegeln, und zwar um mit dem Verschlussnocken bzw. Sperrnocken (40) im Eingriff bzw. eingerastet zu sein, und eine Verzögerungsbeschränkungsantriebsfeder (61) einschließt, welche die Verzögerungsbeschränkungsverriegelungsstange (60) dazu drängt, zu verriegeln, und zwar um mit dem Verschlussnocken bzw. Sperrnocken (40) im Eingriff bzw. eingerastet zu sein, und
der Gehäuserotor (30) eine Vorwärtsbeschränkungskommunikationspassage (31g), welche Fluiddruck zu der Vorwärtsbeschränkungsverriegelungsstange (50) in den Isolationsraum (A2) führt, um das Verriegeln zu lösen, und zwar um mit der vorwärtigen Kammer bzw. Vorwärtskammer (30a) oder der Vorwärtspassage (13) zu kommunizieren, und eine Verzögerungsbeschränkungskommunikationspassage (31h) einschließt, welche Fluiddruck zu der Verzögerungsbeschränkungsverriegelungsstange (60) in den Isolationsraum führt, um das Verriegeln zu lösen, und zwar um mit der rückwärtigen Kammer bzw. Verzögerungskammer (30b) oder der Verzögerungspassage (14) zu kommunizieren.

3. Ventiltaktänderungsvorrichtung nach Anspruch 1 oder 2,
wobei die Verriegelungsstange (50, 60) gestützt wird, um drehbar bzw. schwingbar in einer Ebene zu sein, die senkrecht zu der Achsenlinie (1) ist.

4. Ventiltaktänderungsvorrichtung nach Anspruch 3,
wobei die Verriegelungsstange (50, 60) ausgebildet ist, so dass der Schwerpunkt (G1, G2) davon auf einer Linie angeordnet ist, die das Drehzentrum bzw. Schwingzentrum (S2, S3) davon und die Achsenlinie (S1) der Nockenwelle (10) oder in der Nähe der Linie in einem verriegelten Zustand verbindet, um mit dem Verschlussnocken bzw. Sperrnocken (40) im Eingriff bzw. eingerastet zu sein, um eine Zentrifugalkraft in einer Richtung zu erzeugen, um den verriegelten Zustand beizubehalten und bei einer Position angeordnet ist, die von der Linie in einem Verriegelungs-gelösten Zustand abweicht, und zwar, um von dem Verschlussnocken bzw. Sperrnocken (40) frei bzw. gelöst zu sein, und zwar aufgrund von Fluiddruck, um eine Zentrifugalkraft in einer Richtung zu erzeugen, um den Verriegelungs-gelösten Zustand beizubehalten.

Revendications

1. Dispositif de modification du calage des soupapes pour changer un calage d'ouverture/fermeture d'une soupape d'admission ou d'une soupape d'échappement dont l'ouverture ou la fermeture est mise en oeuvre par un arbre à cames (10), comprenant :

un rotor d'hébergement (30) en rotation autour d'un axe (S1) d'un arbre à cames (10) en lien avec la rotation d'un vilebrequin ;

un rotor à palettes (20) logé dans une chambre de logement (A1) du rotor d'hébergement (30) de manière à être relativement rotatif à l'intérieur d'une plage d'angles prédéterminée tout en divisant la chambre de logement (A1) en une chambre d'avancement (30a) et une chambre de retardement (30b) et qui est mis en rotation intégralement avec l'arbre à cames (10) ;

un passage d'avancement (13) qui fait passer un fluide vers la chambre d'avancement (30a)

un passage de retardement (14) qui fait passer un fluide vers la chambre de retardement (30b), et

un mécanisme de verrouillage (40, 50, 51 60, 61) qui verrouille le rotor à palettes (20) vis-à-vis du rotor d'hébergement (30) dans une position spécifique à l'intérieur de la plage d'angles prédéterminée ;

où le rotor d'hébergement (30) est formé de manière à définir une chambre d'isolation (A2) isolée de la chambre de logement (A1) dans laquelle est logée le rotor à palettes (20) ; et

le mécanisme de verrouillage (40, 50, 51, 60, 61) est disposé dans la chambre d'isolation (A2) ;

où le rotor d'hébergement (30) comprends un organe d'hébergement (31) comprenant une paroi d'isolation (31b) qui isole la chambre d'isolation (A2) de la chambre de logement (A1) et un organe de recouvrement (33) configuré de manière à être attachable et détachable à l'organe d'hébergement (31) pour définir la chambre d'isolation (A2) en coopération avec la paroi d'isolation (31b) ;

caractérisé en ce que :

le mécanisme de verrouillage (40, 50, 51, 60, 61) verrouille le rotor à palettes (20) dans la position intermédiaire à l'intérieur de la plage d'angles prédéterminée au moment du démarrage du moteur ;

où le mécanisme de verrouillage (40, 50, 51, 60, 61) comporte une came de verrouillage (40) connectée au rotor à palettes (20) via un trou de pénétration formé au niveau de la paroi d'isolation (31b) de manière à tourner intégralement, et une barre de verrouillage (50, 60) qui est disposée de manière mobile contre le rotor d'hébergement (30) et qui est apte à être verrouillée en engagement avec la came de verrouillage (40) par une force d'impulsion, le verrouillage étant déverrouillé par la pression du fluide.

2. Dispositif de modification du calage des soupapes selon la revendication 1, comprenant en outre un ressort d'impulsion (51, 61) qui exerce une force d'impulsion pour verrouiller la barre de verrouillage (50, 60) destinée à s'enclencher avec la came de verrouillage (40),
où la barre de verrouillage (50, 60) comprends une barre de verrouillage d'avancement/retenue (50) en engagement avec la came de verrouillage (40) pour empêcher le rotor à palettes (20) de tourner vers un côté d'avancement et une barre de verrouillage de retardement/retenue (60) en engagement avec la came de verrouillage (40) pour empêcher le rotor à palettes (20) de tourner vers un côté de retardement ;
le ressort d'impulsion (51, 61) comporte un ressort d'impulsion d'avancement/retenue (51) qui déclenche le verrouillage de la barre de verrouillage d'avancement/retenue (50) en engagement avec la came de verrouillage (40) et un ressort d'impulsion de retardement/retenue (61) qui déclenche le verrouillage de la barre de verrouillage de retardement/retenue (60) en engagement avec la came de verrouillage (40) ; et
le rotor d'hébergement (30) comporte un passage de communication d'avancement/retenue (31g) qui mène la pression du fluide vers la barre de verrouillage d'avancement/retenue (50) dans la chambre d'isolation (A2) pour déverrouiller le verrouillage de manière à communiquer avec la chambre d'avancement (30a) ou le passage d'avancement (13), et un passage de communication de retardement/retenue (31h) qui mène la pression du fluide vers la barre de verrouillage de retardement/retenue (60) dans la chambre d'isolation (A2) pour déverrouiller le verrouillage de manière à communiquer avec la chambre de retardement (30b) ou le passage de retardement (14).

3. Dispositif de changement du calage des soupapes selon la revendication 1 ou 2,
où la barre de verrouillage (50, 60) est portée de manière pivotable dans un plan perpendiculaire à l'axe (S1).

4. Dispositif de changement du calage des soupapes selon la revendication 3,
où la barre de verrouillage (50, 60) est formée de manière à ce que, dans un état de verrouillage, son barycentre (G1, G2) soit situé sur ou près d'une ligne reliant son centre de pivotement (S2, S3) et l'axe (S1) de l'arbre à cames (10) permettant l'engagement avec la came de verrouillage (40) afin de générer une force centrifuge dans une direction pour maintenir l'état de verrouillage et, dans un état de déverrouillage, soit situé en une position à l'écart de la ligne permettant le désengagement d'avec la came de verrouillage (40) en raison de la pression du fluide afin de générer une force centrifuge dans une direction pour maintenir l'état de déverrouillage.

Drawing