(19)
(11)EP 2 839 123 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
19.10.2016 Bulletin 2016/42

(21)Application number: 13718565.8

(22)Date of filing:  19.04.2013
(51)International Patent Classification (IPC): 
F01L 1/04(2006.01)
F01L 13/00(2006.01)
F01L 1/18(2006.01)
(86)International application number:
PCT/EP2013/058208
(87)International publication number:
WO 2013/156610 (24.10.2013 Gazette  2013/43)

(54)

A ROCKER ARM

SCHALTBARER KIPPHEBEL

CULBUTEUR COMMUTABLE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 19.04.2012 EP 12164703

(43)Date of publication of application:
25.02.2015 Bulletin 2015/09

(60)Divisional application:
16187700.6

(73)Proprietor: Eaton S.r.l.
10149 Torino (TO) (IT)

(72)Inventor:
  • CECUR, Majo
    I-10086 Rivarolo Canavese (IT)

(74)Representative: Eaton IP Group EMEA 
c/o Eaton Industries Manufacturing GmbH Route de la Longeraie 7
1110 Morges
1110 Morges (CH)


(56)References cited: : 
EP-A1- 0 735 249
EP-A1- 1 561 013
EP-A2- 1 149 988
WO-A2-2011/156684
DE-A1-102010 011 826
US-A- 5 529 033
US-A1- 2001 027 765
US-A1- 2006 144 356
US-A1- 2008 223 324
US-A1- 2010 236 507
US-A1- 2011 005 483
US-A1- 2011 226 208
EP-A1- 0 767 296
EP-A1- 1 785 595
EP-A2- 1 338 760
DE-A1- 2 753 197
US-A- 5 524 580
US-A1- 2001 023 675
US-A1- 2001 035 140
US-A1- 2008 127 917
US-A1- 2010 043 737
US-A1- 2010 275 864
US-A1- 2011 197 842
US-B1- 6 314 928
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of the Invention



    [0001] The present invention relates to a rocker arm.

    Background of the Invention



    [0002] Dual life rocker arms for control of valve actuation by alternative between at least two or more modes of operation are known. Such rocker arms typically involve multiple bodies, such as an inner arm and an outer arm, that are latched together to provide one mode of operation and are unlatched, and hence can pivot with respect to each other, to provide a second mode of operation. The so called Type II valve train (i.e. end pivot rocker arm, overhead cam) is the most commonly used valve train in both modem petrol and diesel internal combustion engines. Dual lift rocker arms for this type of valve train often use a three lobe camshaft wherein a first and a second of the lobes control one type of valve lift. Typically in such arrangements, the outer arm of the dual lift rocker arm is provided with a roller for making a roller contact with the third of the lobes. The manufacturing of such rocker arms involves producing the sliding contacts by investment casting, attaching them by soldering and coating with a low-friction coating. This is an involved and relatively expensive process.

    [0003] US2008/223324 describes a two-step rocker arm comprising an arm member, a roller assembly in selective engagement with a low lift cam, roller assemblies and disposed on either side of the arm member and in engagement with a respective one of first and second high lift cams. The roller assemblies and are rotatably supported by a shaft member. The shaft member extends through the arm member and the roller assembly and cooperates with a generally C-shaped or curved opening defined by the roller assembly to allow relative motion between the roller assemblies and the arm member. A coupling lever is provided for locking and unlocking the shaft member in position.

    [0004] It would be desirable to produce a rocker arm that can be manufactured more easily and cost effectively.

    Summary of the Invention



    [0005] In accordance with the invention there is provided a rocker arm according to claim 1.

    [0006] Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, given by way of example only, which is made with reference to the accompanying drawings.

    Brief Description of the Drawings



    [0007] 

    Figure 1 illustrates a schematic perspective view of a valve train assembly including a dual lift rocker arm;

    Figure 2 illustrates another perspective view of the valve train assembly;

    Figure 3a illustrates a perspective view of an inner body of the dual lift rocker arm;

    Figure 3b illustrates another perspective view of the inner body;

    Figure 4a illustrates a perspective view of an outer body of the dual lift rocker arm;

    Figure 4b illustrates another perspective view of the outer body;

    Figure 5 is an exploded view of the dual lift rocker arm;

    Figures 6a and 6b schematically illustrate the valve train assembly at two different points in engine cycle when the inner and outer bodies are latched;

    Figures 7a and 7b schematically illustrate the valve train assembly at two different points in engine cycle when the inner and outer bodies are unlatched;

    Figure 8 illustrates a graph showing valve lift against cam shaft rotation.


    Detailed Description of Illustrative Embodiments of the Invention



    [0008] Referring first to Figures 1 and 2, a valve train assembly 1 comprises a dual lift rocker arm 2, an engine valve 4 for an internal combustion engine cylinder (not shown) and a lash adjustor 6. The rocker arm 2 comprises an inner body or arm 8 and an outer body or arm 10. The inner body 8 is pivotally mounted on a shaft 12 which serves to link the inner body 8 and outer body 10 together. A first end 14 of the outer body 10 engages the stem 16 of the valve 4 and at a second end 20 the outer body 10 is mounted for pivotal movement on the lash adjustor 6 which is supported in an engine block (not shown). The lash adjuster 6, which may for example be a hydraulic lash adjuster, is used to accommodate slack between components in the valve train assembly 1. Lash adjusters are well known per se and so the lash adjuster 6 will not be described in detail.

    [0009] The rocker arm 2 is provided with a pair of main lift rollers 22a and 22b rotatably mounted on an axle 24 carried by the outer body 10. One of the main lift rollers 22a is located one side of the outer body 10 and the other of the main lift rollers 22b is located the other side of the outer body 10. The rocker arm 2 is further provided with a secondary lift roller 26, located within the inner body 8 and rotatably mounted on an axle (not visible in Figures 1 and 2) carried by the inner body 8..
    A three lobed camshaft 30 comprises a rotatable camshaft 32 mounted on which are first 34 and second 36 main lift cams and a secondary lift cam 38. The secondary lift cam 38 is positioned between the two main lift cams 34 and 36. The first main lift cam 34 is for engaging the first main lift roller 22a, the second main lift cam 36 is for engaging the second main lift roller 22b and the secondary lift cam 38 is for engaging the secondary lift roller 26. The first main lift cam 34 comprises a lift profile (i.e. a lobe) 34a and a base circle 34b, second main lift cam 36 comprises a lift profile 36a and a base circle 36b and the secondary lift cam 38 comprises a lift profile 38a and a base circle 38b. The lift profiles 34a and 36a are substantially of the same dimensions as each other and are angularly aligned. The lift profile 38a is smaller than the lift profiles 34a (both in terms of the height of its peak and in terms of the length of its base) and is angularly offset from them.

    [0010] The rocker arm 2 is switchable between a dual lift mode which provides two operations of the valve 4 (a valve operation is an opening and corresponding closing of the valve) per engine cycle (e.g. full rotation of the cam shaft 32) and a single lift mode which provides a single operation of the valve 4 per engine cycle. In the dual lift mode, the inner body 8 and the outer body 10 are latched together by a latching arrangement 40 (see Figure 2) and hence act as a single solid body. With this particular arrangement, the dual lift mode provides a higher main valve lift and a smaller secondary valve lift per engine cycle. The single lift mode provides just the main valve lift per engine cycle.

    [0011] During engine operation in the dual lift mode, as the cam shaft 32 rotates, the first main lift cam's lift profile 34a engages the first main lift roller 22a whilst, simultaneously, the second main lift cam's lift profile 36a engages the second main lift roller 22b and together they exert a force that causes the outer body 10 to pivot about the lash adjuster 6 to lift the valve stem 16 (i.e. move it downwards in the sense of the page) against the force of a valve spring (not shown) thus opening the valve 4. As the peaks of the lift profiles 34a and 36a respectively pass out of engagement with the first main lift roller 22a and the second main lift roller 22b, the valve spring (not shown) begins to close the valve 4 (i.e. the valve stem 16 is moved upwards in the sense of the page). When the first main lift cam's base circle 34b again engages the first main lift roller 22a and the second main lift cam's 36 lift profile engages the second main lift roller 22b the valve is fully closed and the main valve lift event is complete.

    [0012] As the camshaft 32 continues to rotate, then, the secondary lift cam's lift profile 38a engages the secondary lift roller 26 exerting a force on the inner body 8 which force, as the inner body 8 and the outer body 10 are latched together, is transmitted to the outer body 10 causing the outer body 10 to pivot about the lash adjuster 6 to lift the valve stem 16 against the force of a valve spring (not shown) thus opening the valve 4 a second time during the engine cycle. As the peak of the lift profile 38a passes out of engagement with the secondary lift roller 26 the valve spring (not shown) begins to close the valve 4 again. When the secondary lift cam's base circle 38b again engages the secondary lift roller 26 the valve 4 is fully closed and the second valve lift event for the current engine cycle is complete.

    [0013] The lift profile 38a is shallower and narrower than are the lift profiles 34a and 36a and so consequently the second valve lift event is lower and of a shorter duration than is the first valve lift event.

    [0014] In the single lift mode the inner body 8 and the outer body 10 are not latched together by the latching arrangement 40 and hence in this mode, the inner body 8 is free to pivot with respect to the outer body 10 about the shaft 12. During engine operation in the single lift mode, as the cam shaft 32 rotates, when the first main lift cam's lift profile 34a engages the first main lift roller 22a and the second main lift cam's lift profile 36a engages the second main lift roller 22b, the outer body 10 pivots about the lash adjuster 6 and, in an identical way as in the dual lift mode, a main valve lift event occurs. As the camshaft 32 continues to rotate, then, the secondary lift cam's lift profile 38a engages the secondary lift roller 26 exerting a force on the inner body 8. In the single lift mode, however, as the inner body 8 and the outer body 10 are not latched together, this force is not transmitted to the outer body 10 which hence does not pivot about the lash adjuster 6 and so there is no additional valve event during the engine cycle. Instead, as the secondary lift cam's lift profile 38a engages the secondary lift roller 26, the inner body 8 pivots with respect to the inner body 10 about the shaft 12 accommodating the motion that otherwise would be transferred to the outer body 10. A torsional lost motion spring (not shown in Figures 1 and 2) is provided to return the inner body 8 to its starting position relative to the outer body 10, once the peak of the lift profile 38a has passed out of engagement with the secondary lift roller 26.

    [0015] In one embodiment, this arrangement may be used to provide switchable Internal Exhaust Gas Recirculation (IEGR) control. For example, if the valve 4 is an exhaust valve for an engine cylinder, the main valve lift acts as the main exhaust lift of an engine cycle, and the timing of the secondary valve lift may be arranged so that it occurs when an intake valve for that cylinder, controlled by a further rocker arm (not shown) mounted pivotally on a further lash adjuster (not shown) and which pivots in response to an intake cam (not shown) mounted on the cam shaft 32, is open. The simultaneous opening of the intake and exhaust valves in this way ensures that a certain amount of exhaust gas remains in the cylinder during combustion which, as is well known, reduces NOx emissions. Switching to the single lift mode deactivates the IEGR function, which deactivation may be desirable under certain engine operating conditions. As will be appreciated by those skilled in the art, this switchable IEGR control may also be provided if the valve 4 is an intake valve with the timing of the secondary valve lift arranged to occur when an exhaust valve for that cylinder is open during the exhaust part of an engine cycle.

    [0016] Figures 3a and 3b illustrate the inner body 8 which comprises parallel first 40 and second 42 side walls and, at a first end 43, an end wall 44 connecting the first 40 and second 42 side walls. Towards a second end 45 of the inner body 8, each of the first 40 and second 42 side walls defines a respective one of a first pair of holes 46a, 46b which receive the shaft 12. Towards the first end 43, each of the first 40 and second 42 side walls defines a respective one of a second pair of larger diameter holes 48a, 48b which receive an axle 43 (See Figure 5) on which the secondary lift roller 26 is mounted. An outer face of the end wall 44 has a recessed portion 52 partly defined by a downward facing latch contact surface 54 for engaging the latching mechanism 40 when in the dual lift mode.

    [0017] Figures 4a and 4b illustrate the outer body 10 which comprises parallel first 60 and second 62 side walls, a first base portion 64a at the first end 14, a second base portion 64b at the second end 20, an end wall 66, at the second end 20, connecting the first 60 and second 62 side walls, and an interior wall 68 which also connects the first 60 and second 62 side walls and is parallel with the end wall 66. Towards the first end 14 of the outer body 10, each of the first 60 and second 62 side walls defines a respective one of a first pair of holes 70a, 70b which receive the shaft 12. Part way between the first end 14 and the second end 20, each of the first 60 and second 62 side walls defines a respective one of a second pair of holes 72a, 72b which receive the axle 24. The end wall 66 and the interior wall 68 each respectively define one of a third pair of holes 74a, 74b for receiving and guiding a latch pin 80 (see Figure 5).

    [0018] The first base portion 64a defines a recess 76 for engaging the end of the valve stem 16 and the second base portion 64b defines a part spherical recess 78 to permit pivoting about a part spherical end of the lash adjuster 6.

    [0019] Advantageously, as the rocker arm 2 incorporates three roller contacts for the camshaft 30 and no slider contacts, the outer body 10 and the inner body 8 may be manufactured from stamped sheet metal. The latch contact surface 54 may be formed in the inner body 8 by stamping (shearing) using a suitable stamping tool. The use of stamped sheet metal provides for a cost effective manufacturing process. The roller contacts also provide relatively low friction contacts with the cams without the need for low friction coatings.

    [0020] As is best understood from Figure 5, the secondary lift roller 26 is mounted on a hollow inner bushing/ axle 43 which is supported in the apertures 48a and 48b. The axle 24 extends through the inner bushing/axle 43 (and hence through the inner roller 26) and the diameter of the axle 24 is somewhat smaller than the inner diameter of the inner bushing/axle 43 to allow movement of the assembly of the inner body 8, axle 43 and inner roller 26 relative to the outer body 10. The main lift rollers 22a and 22b are therefore arranged along a common longitudinal axis and the secondary lift roller 26 is arranged along a longitudinal axis that is slightly offset from this. This arrangement of axles and rollers ensures that the rocker 2 arm is compact and facilitates manufacturing the first 10 and second bodies from stamped metal sheets.

    [0021] As is also best seen from Figure 5, the latching arrangement 40 comprises the latch pin 80 and an actuation member 84. The actuation member 84 comprises a sheet bent along its width to form first 84a and second 84b rectangular portions which define a right angle. The first portion 84a defines a hole 84c. The actuation member 82 further comprises a pair of winged portions extending rearwardly from the second portion 84c each of which defines a respective one of a pair of apertures 86a, 86b for supporting a shaft 88 on which is mounted a roller 90. The actuation member 84 straddles the end wall 66 of the outer body 10 with the second portion 84c slidably supported on the end wall 66 with the first portion 84a positioned between the end wall 66 and the inner wall 68 of the outer body 10. At one end, the latch pin 80 defines an upward facing latch surface 92.

    [0022] As seen in Figures 6 and 7, the latch pin 80 extends through the holes 74a in the end wall 66 and the hole 84c in the actuation member 82 and its end 93 engages the wing portions of the actuation member 84.

    [0023] Figures 6a and 6b illustrate the valve train assembly 1 when the rocker arm 2 is in the single lift mode (i.e. unlatched configuration). In this configuration, the actuation member 82 and latch pin 80 are positioned so that the latch surface 92 does not extend through the hole 74b and so does not engage the latch contact surface 54 of the inner body 8. In this configuration, the inner body 8 is free to pivot, with respect to the outer body 10, about the shaft 12 when the secondary roller 26 engages the lift profile 38a and hence there is no additional valve event. It will be appreciated that the amount of movement available to the inner body 8 relative to the outer body 10 (i.e. the amount of lost motion absorbed by the inner body 8) is defined by the size difference between the diameter of the axle 24 and the inner diameter of the inner bushing/axle 43. The torsional spring 67, which is installed over the top of the valve stem 16 and is located inside the inner body 10 by the shaft 12, acts as a lost motion spring that returns the inner body 8 to its starting position with respect to the outer body 10 after it has pivoted.

    [0024] Figures 7a and 7b illustrate the valve train assembly 1 when the rocker arm 2 is in the dual lift mode (i.e. a latched configuration). In this configuration, the actuation member 82 and latch pin 80 are moved forward (i.e. to the left in the Figures) relative to their positions in the unlatched configuration so that the latch surface 92 does extend through the hole 74b so as to engage the latch contact surface 54 of the inner body 8. As explained above, in this configuration, the inner body 8 and the outer body 10 act as a solid body so that when the when the secondary roller 26 engages the lift profile 38a there is an additional valve event.

    [0025] An actuator 94 is provided to move the latching arrangement 40 between the un-latched and latched positions. In this example, the actuator comprises an actuator shaft 96 and a biasing means 98, preferably a leaf spring. In the default unlatched configuration, the leaf spring 98 does not engage the latching arrangement 40. To enter the latched configuration, the shaft 96 is rotated a certain amount (for example 12 degrees) causing the leaf spring 98 to engage the roller 88 and to push the latching arrangement 40 into the latched position. A spring 85 mounted over the latch pin 80 and supported between an outer face of the end wall 66 and the winged members of the member 84 is biased to caused the latching arrangement 40 to return to its unlatched position when the actuator shaft 96 is rotated back to its unlatched position and the leaf spring 98 disengages the roller 88.

    [0026] Other types of actuators for the latching arrangement that may for example make use of pressurised oil, electromechanical systems or pneumatic systems will be known to those skilled in the art.

    [0027] The actuator shaft 94 may also be used as an oil spray bar that sprays oil to lubricate or cool the valve train components.

    [0028] Advantageously, when the base circle 38b engages the inner bushing/axle 43, the inner bushing axle 43 stops always on the axle 24 which ensures that the orientation of the various components is such that the latch pin 80 is free to move in and out of the latched and unlatched positions.

    [0029] Figure 6a illustrates the valve train assembly 1 when the rocker arm 2 is in the single lift mode (i.e. the un-latched configuration) at a point in an engine cycle when the main lift rollers 22a and 22b are engaging the respective base circles 34b and 36b of the first main lift cam 34 and the second main lift cam 36. At this point in the engine cycle, the valve 4 is closed. Figure 6b illustrates the valve train assembly 1 when the rocker arm 2 is in the single lift mode at another point in an engine cycle when the main lift rollers 22a and 22b are engaging the respective peaks of the lift profiles 34a and 36a of the first main lift cam 34 and the second main lift cam 36. At this point in the engine cycle the valve 4 is fully open and the 'maximum lift' of the main valve event is indicated as M.

    [0030] Figure 7a illustrates the valve train assembly 1 when the rocker arm 2 is in the dual lift mode (i.e. the latched configuration) at a point in an engine cycle when the main lift rollers 22a and 22b are engaging the respective base circles 34b and 36b of the first main lift cam 34 and the secondary lift roller 26 is engaging the base circle 38b of the secondary lift cam 38. At this point in the engine cycle, the valve 4 is closed. Figure 7b illustrates the valve train assembly 1 when the rocker arm 2 is in the single lift mode at another point in an engine cycle when the main lift rollers 22a and 22b are engaging the respective base circles 34b and 36b of the first main lift cam 34 and the second main lift cam 36 and the secondary lift roller 26 is engaging the peak of the lift profile 38a of the secondary lift cam 38.. At this point in the engine cycle the valve 4 is fully open during the additional valve event and the 'maximum lift' of the secondary valve event is indicated as M'.

    [0031] Figure 8 illustrates a graph in which the Y axis indicates valve lift and the X axis indicates rotation of the cam shaft. In the example of the valve 4 being an exhaust valve, the curve 100 represents the main lift of the exhaust valve during an engine cycle and the curve represents 101 the additional lift of the exhaust valve during the subsequent engine cycle. The curve 102 represents the lift of intake valve (not shown in the figures), during the subsequent engine cycle, operated by an intake rocker arm (again not shown in the Figures) in response to an intake cam (not shown in the Figures) mounted on the cam shaft. It can be seen that the cams are arranged so that in any given engine cycle, the additional smaller opening of the exhaust valve occurs when the intake valve is open to thereby provide a degree of internal exhaust gas recirculation.

    [0032] As previously mentioned, in an alternative arrangement (not illustrated) the valve 4 is an intake valve rather than an exhaust valve (making the rocker arm 2 an intake rocker arm) and an exhaust rocker arm operates an exhaust valve in response to an exhaust cam mounted on the cam shaft. In this alternative arrangement the cams are arranged so that in any given engine cycle, the additional smaller opening of the intake valve occurs when the exhaust valve is open to thereby provide a degree of internal exhaust gas recirculation.

    [0033] The above embodiment is to be understood as an illustrative example of the invention only. Further embodiments of the invention are envisaged. Although in the described embodiment, in one mode of operation, there are two different valve lifts per engine cycle (a high lift at one point in the cycle and a low lift in another part of the cycle) the rocker arm may be arranged to provide alternative types of dual mode operation, for example, a first mode in which there is a single type of valve lift (e.g. a high lift) per engine cycle and a second mode in which there is a different single type of valve lift (e.g. a lower lift) per engine cycle. The different lifts may be at the same point or at different points in the engine cycle. Accordingly, although in the described embodiment the valve train 1 is arranged so that the additional lift provides for IEGR, it is to be understood that this is only a preferred example of a use of an embodiment of the invention. It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.


    Claims

    1. A rocker arm (2) comprising:

    a first body (10) supporting a first axle (24) on which a first roller (22a, 22b) for engaging a first rotatable cam surface (34, 36) and a second roller (22a, 22b) for engaging a second rotatable cam surface (34, 36) are mounted, whereby at least part of the rocker arm (2) can be pivoted by the first rotatable cam surface (34, 36) acting on the first roller (22a, 22b) and the second rotatable cam surface (34, 36) acting on the second roller (22a, 22b) to move a valve (4) to cause a first valve event; and

    a second body (8) supporting a second axle (43) on which a further roller (26) for engaging a further rotatable cam surface (38) is mounted, whereby at least part of the rocker arm (10) can be pivoted by the further rotatable cam surface (38) to move the valve (4) to cause a second valve event, and;

    wherein one of the first (10) and second (8) bodies is pivotally mounted with respect to the other of the first (10) and second (8) bodies, and characterised in that one of the first (24) and second (43) axles defines a circular aperture and the other of the first (24) and second (43) axles extends through the circular aperture and wherein an outer diameter of the other of the first (24) and second (43) axles that extends through the circular aperture is smaller than a diameter of the circular aperture to permit relative pivotal movement of the first body (10) and the second body (8) when the first body (10) and the second body (8) are un-latched from each other.


     
    2. A rocker arm (2) according to claim 1, wherein the rocker arm (2) is configurable in a first mode of operation in which one of the first and second valve events occurs and a second mode of operation in which both the first and second valve events occur or the other of the first and second valve events occurs.
     
    3. A rocker arm (2) according to claim 2 further comprising a latching mechanism (40) for latching and un-latching the first (10) and second (8) bodies together and wherein which of the first and second modes the rocker arm (2) is configured in depends upon whether the first (10) and second (8) bodies are latched or are unlatched.
     
    4. A rocker arm (2) according to claim 3 wherein the latching mechanism (40) comprises a latch member (80) which in use is moveable by a latching actuator (94) between a latched position wherein it latches the first (10) and second (8) bodies together and an unlatched position in which the first (10) and second (8) bodies are unlatched.
     
    5. A rocker arm (2) according to claim 4 wherein the latch member (80) is a latch pin comprising a latch surface (92) for engaging one or other of the first (10) and second (8) bodies to prevent relative pivotal movement of the first (10) and second (8) bodies.
     
    6. A rocker arm (2) according to claim 5 wherein at least one of the first body (10) and second (8) bodies defines a guide hole for guiding the latch pin when it moves between the latched and unlatched positions.
     
    7. A rocker arm (2) according to any of claims 4 to 6 wherein the actuator (94) comprises a rotatable shaft (96) attached to a biasing means (98), wherein rotating the shaft (96) from a first position to a second position causes the biasing means (98) to move the latch member (80) between the latched position and the unlatched position.
     
    8. A rocker arm (2) according to any of claims 3 to 7 wherein when the first (10) and second (8) bodies are unlatched the rocker arm (2) is in the first mode of operation and when the further roller (26) engages a lobe of the further rotatable cam surface (38), the second body (8) pivots with respect to the first body (10) so that the first body is prevented from causing the second valve event.
     
    9. A rocker arm (2) according to any of claims 2 to 8 wherein one of the first (10) and second (8) bodies is mounted within the other of the first (10) and second (8) bodies.
     
    10. A valve train assembly comprising:

    a rocker arm according to any of claims 1 to 9;

    a cam shaft having the first rotatable cam surface, the second rotatable surface and the further rotatable cam surface.


     
    11. A valve train assembly according to claim 10, wherein one of the first and second valve events is of a longer duration than the other of the valve events and/or one of the first and second valve events is of a higher lift than the other of the valve events.
     
    12. A valve train assembly according to claim 10 or 11 wherein the valve (4) is an exhaust valve or an intake valve for an engine cylinder and wherein the first valve event is a main lift of the valve and the second valve event is a secondary lift of the valve arranged to enable exhaust gas recirculation.
     


    Ansprüche

    1. Schaltbarer Kipphebel (2), umfassend:

    einen ersten Körper (10), der eine erste Achse (24) trägt, auf der ein erster Rollkörper (22a, 22b) zum Eingriff in eine erste rotierbare Mitnehmerfläche (34, 36) und ein zweiten Rollkörper (22a, 22b) zum Eingriff in eine zweite rotierbare Mitnehmerfläche (34, 36) montiert sind, wobei mindestens ein Teil des schaltbaren Kipphebels (2) geschwenkt werden kann durch die erste rotierbare Mitnehmerfläche (34, 36), die an dem ersten Rollkörper (22a, 22b) angreift und die zweite rotierbare Mitnehmerfläche (34, 36), die an dem zweiten Rollkörper (22a, 22b) angreift, um ein Ventil (4) zu bewegen, um einen ersten Ventilvorgang zu verursachen; und

    ein zweiter Körper (8), der eine zweite Achse (43) trägt, auf der ein weiterer Rollkörper (26) zum Eingriff in eine weitere rotierbare Mitnehmerfläche (38) montiert ist, wobei mindestens ein Teil des schaltbaren Kipphebels (10) durch die weitere rotierbare Mitnehmerfläche (38) geschwenkt werden kann, um das Ventil (4) zu bewegen, um einen zweiten Ventilvorgang zu verursachen, und;

    wobei einer des ersten (10) und zweiten (8) Körpers in Bezug auf den anderen des ersten (10) und zweiten (8) Körpers schwenkbar montiert ist, und dadurch gekennzeichnet ist, dass einer der ersten (24) und zweiten (43) Achsen eine kreisförmige Blende definiert und die andere der ersten (24) und zweiten (43) Achse sich durch eine kreisförmige Blende hindurch erstreckt und wobei ein äußerer Durchmesser der anderen der ersten (24) und zweiten (43) Achsen, die sich durch die kreisförmige Blende erstreckt, kleiner ist, als ein Durchmesser der kreisförmigen Blende, um eine relative Schwenkbewegung des ersten Körpers (10) und des zweiten Körpers (8) zu verhindern, wenn der erste Körper (10) und der zweite Körper (8) voneinander entriegelt sind.


     
    2. Schaltbarer Kipparm (2) nach Anspruch 1, wobei der schaltbare Kipparm (2) in ein einem ersten Betriebsmodus konfigurierbar ist, in welchem einer der ersten und zweiten Ventilvorgänge stattfindet und ein zweiter Betriebsmodus, in welchem sowohl der erste als auch der zweite Ventilvorgang stattfindet oder der andere der ersten und zweiten Ventilvorgänge stattfindet.
     
    3. Schaltbarer Kipparm (2) nach Anspruch 2, ferner umfassend einen Verriegelungsmechanismus (40) zum Verriegeln und Entriegeln des ersten (10) und zweiten (8) Körpers miteinander und wobei in welchem der ersten und zweiten Modi der schaltbare Kipparm (2) konfiguriert ist, davon abhängt, ob der erste (10) und zweite (8) Körper verriegelt oder entriegelt sind.
     
    4. Schaltbarer Kipparm (2) nach Anspruch 3, wobei der Verriegelungsmechanismus (40) eine Verriegelungsteil (80) umfasst, welches bei Verwendung durch einen Verriegelungsaktuator (94) zwischen einer verriegelten Position, wobei diese den ersten (10) und zweiten (8) Körper miteinander verriegelt, und einer entriegelten Position, in der der erste (10) und der zweite Körper (8) entriegelt sind, bewegbar ist.
     
    5. Schaltbarer Kipparm (2) nach Anspruch 4, wobei das Verriegelungsteil (80) ein Verriegelungsstift ist, der eine Verriegelungsoberfläche (92) zum Eingriff in einen oder den anderen des ersten (10) und zweiten (8) Körpers umfasst, um eine relative Schwenkbewegung des ersten (10) und zweiten (8) Körpers zu verhindern.
     
    6. Schaltbarer Kipparm (2) nach Anspruch 5, wobei mindestens einer des ersten Körpers (10) und zweiten (8) Körpers ein Führungsloch zur Führung des Verriegelungsstifts definiert, wenn sich dieser zwischen den verriegelten und entriegelten Positionen bewegt.
     
    7. Schaltbarer Kipparm (2) nach einem der Ansprüche 4 bis 6, wobei der Aktuator (94) eine rotierbare Welle (96) umfasst, die an einem Vorspannmittel (98) angebracht ist, wobei Rotieren der Welle (96) aus einer ersten Position in eine zweite Position das Vorspannmittel (98) veranlasst, das Verriegelungsteil (80) zwischen der verriegelten Position und der entriegelten Position zu bewegen.
     
    8. Schaltbarer Kipparm (2) nach einem der Ansprüche 3 bis 7, wobei wenn der erste (10) und zweite (8) Körper entriegelt sind, der schaltbare Kipparm (2) in dem ersten Betriebsmodus ist und wenn der weitere Rollkörper (26) in einen Nockenbuckel der weiteren rotierbaren Mitnehmerfläche (38) eingreift, der zweite Körper (8) in Bezug auf den ersten Körper (10) schwenkt, so dass der erste Körper davon abgehalten wird, den zweiten Ventilvorgang zu verursachen.
     
    9. Schaltbarer Kipparm (2) nach einem der Ansprüche 2 bis 8, wobei einer des ersten (10) und zweiten (8) Körpers innerhalb des anderen des ersten (10) und zweiten (8) Körpers montiert ist.
     
    10. Ventilantrieb, umfassend:

    einen schaltbaren Kipparm nach einem der Ansprüche 1 bis 9;

    eine Nockenwelle mit der ersten rotierbaren Mitnehmerfläche, der zweiten rotierbaren Oberfläche und der weiteren rotierbaren Mitnehmerfläche.


     
    11. Ventilantrieb nach Anspruch 10, wobei einer des ersten und zweiten Ventilvorgangs von einer längeren Dauer ist als der andere der Ventilvorgänge und/oder einer des ersten und zweiten Ventilvorgänge einen höheren Anhub hat als der andere der Ventilvorgänge.
     
    12. Ventilantrieb nach Anspruch 10 oder 11, wobei das Ventil (4) ein Auspuffventil oder ein Einlassventil für einen Motorzylinder ist und wobei der erste Ventilvorgang der Haupthub des Ventils ist und der zweite Ventilvorgang ein sekundärer Anhub des Ventils ist, das angeordnet ist, Rezirkulation von Auspuffgas zu ermöglichen.
     


    Revendications

    1. Culbuteur (2) comprenant :

    un premier corps (10) supportant un premier axe (24) sur lequel un premier rouleau (22a, 22b) pour mettre en prise une première surface de came rotative (34, 36) et un second rouleau (22a, 22b) pour mettre en prise une seconde surface de came rotative (34, 36) sont montés, de sorte qu'au moins une partie du culbuteur (2) peut être pivotée par la première surface de came rotative (34, 36) agissant sur le premier rouleau (22a, 22b) et la seconde surface de came rotative (34, 36) agissant sur le second rouleau (22a, 22b) pour déplacer une soupape (4) pour provoquer un premier événement de soupape ; et

    un second corps (8) supportant un second axe (43) sur lequel un rouleau supplémentaire (26) pour mettre en prise une surface de came rotative supplémentaire (38) est monté, de sorte qu'au moins une partie du culbuteur (10) peut être pivotée par la surface de came rotative supplémentaire (38) pour déplacer la soupape (4) pour provoquer un second événement de soupape, et ;

    dans lequel un des premier (10) et second (8) corps est monté de manière pivotante par rapport à l'autre des premier (10) et second (8) corps, et caractérisé en ce qu'un des premier (24) et second (43) axes définit une ouverture circulaire et l'autre des premier (24) et second (43) axes s'étend à travers l'ouverture circulaire et dans lequel un diamètre extérieur de l'autre des premier (24) et second (43) axes qui s'étend à travers l'ouverture circulaire est plus petit qu'un diamètre de l'ouverture circulaire pour permettre un mouvement pivotant relatif du premier corps (10) et du second corps (8) lorsque le premier corps (10) et le second corps (8) ne sont pas verrouillés l'un à l'autre.


     
    2. Culbuteur (2) selon la revendication 1, dans lequel le culbuteur (2) peut être configuré dans un premier mode de fonctionnement dans lequel un des premier et second événements de soupape se produit et un second mode de fonctionnement dans lequel tant le premier que le second événement de soupape se produisent ou l'autre des premier et second événements de soupape se produit.
     
    3. Culbuteur (2) selon la revendication 2, comprenant en outre un mécanisme de verrouillage (40) pour verrouiller et déverrouiller les premier (10) et second (8) corps ensemble et dans lequel celui des premier et second modes dans lequel le culbuteur (2) est configuré est fonction de si le premier (10) et le second (8) corps sont verrouillés ou sont non verrouillés.
     
    4. Culbuteur (2) selon la revendication 3, dans lequel le mécanisme de verrouillage (40) comprend un élément formant verrou (80) qui en fonctionnement est mobile par un dispositif d'actionnement de verrouillage (94) entre une position verrouillée dans laquelle il verrouille le premier (10) et le second (8) corps ensemble et une position non verrouillée dans laquelle le premier (10) et le second (8) corps sont non verrouillés.
     
    5. Culbuteur (2) selon la revendication 4, dans lequel l'élément formant verrou (80) est un ergot de verrou comprenant une surface de verrou (92) pour mettre en prise l'un ou l'autre des premier (10) et second (8) corps pour empêcher un mouvement pivotant relatif des premier (10) et second (8) corps.
     
    6. Culbuteur (2) selon la revendication 5, dans lequel au moins un du premier corps (10) et du second corps (8) définit un trou de guidage pour guider l'ergot de verrou quand il se déplace entre les positions verrouillée et non verrouillée.
     
    7. Culbuteur (2) selon l'une quelconque des revendications 4 à 6, dans lequel le dispositif d'actionnement (94) comprend un arbre rotatif (96) attaché à un moyen de déplacement (98), dans lequel la rotation de l'arbre (96) d'une première position à une seconde position amène le moyen de déplacement (98) à déplacer l'élément formant verrou (80) entre la position verrouillée et la position non verrouillée.
     
    8. Culbuteur (2) selon l'une quelconque des revendications 3 à 7, dans lequel lorsque les premier (10) et second (8) corps sont non verrouillés, le culbuteur (2) est dans le premier mode de fonctionnement et lorsque le rouleau supplémentaire (26) met en prise un lobe de la surface de came rotative supplémentaire (38), le second corps (8) pivote par rapport au premier corps (10) de sorte que le premier corps est empêché de provoquer le second événement de soupape.
     
    9. Culbuteur (2) selon l'une quelconque des revendications 2 à 8, dans lequel un des premier (10) et second (8) corps est monté à l'intérieur de l'autre des premier (10) et second (8) corps.
     
    10. Ensemble de train de soupapes comprenant :

    un culbuteur selon l'une quelconque des revendications 1 à 9 ;

    un arbre à cames ayant la première surface de came rotative, la seconde surface rotative et la surface de came rotative supplémentaire.


     
    11. Ensemble de train de soupapes selon la revendication 10, dans lequel un des premier et second événements de soupape a une durée plus longue que l'autre des événements de soupape et/ou un des premier et second événements de soupape a un soulèvement plus élevé que l'autre des événements de soupape.
     
    12. Ensemble de train de soupapes selon la revendication 10 ou 11, dans lequel la soupape (4) est une soupape d'échappement ou une soupape d'admission pour un cylindre de moteur et dans lequel le premier événement de soupape est un soulèvement principal de la soupape et le second événement de soupape est un soulèvement secondaire de la soupape agencé pour permettre le recyclage des gaz d'échappement.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description