Piston-type compressor inlet valve

Abstract

 The present invention relates to a piston-type compressor comprising a casing having a plurality of bores, a plurality of pistons respectively inserted into each bore, a driving means for sequentially moving said pistons to suck and to discharge a gas into and from the bores, an sucking valve mechanism including a valve seat plate and an sucking valves, and a discharging valve mechanism.
In such compressor, whole of an abutted area on the valve seat plate or the whole of the abutting area on each sucking valve to be abutted to the valve seat plate is roughed. Thus, separation of the sucking valve from the valve seat plate in sucking the gas into the bores is facilitated.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The present invention relates to a piston type compressor, and in particular to a sucking valve mechanism thereof which can reduce a sucking pulsating.

Related Background Art

[0002] There are some types of the piston type compressor in which a plurality of pistons are arranged to be moved sequentially and reciprocately to suck and to discharge gas such as a refrigerant gas, one of the most typical type of which is a swash-plate type compressor. The swash-plate type compressor is generally comprised of a cylinder block having plural bores, a valve seat plate having sucking ports and discharging ports formed thereon, sucking and discharging valve plates having sucking valves or discharging valves provided thereon, and a pair of housing for forming at one side of the cylinder block a crank chamber to dispose a swash plate therein and for holding at other side of the cylinder block the valve seat plate and two valve plates.

[0003] The sucking valve is held to assume a closed (contacted) position contacting a valve seat surface of the valve seat plate for closing the sucking port, and an opened (separated) position separated therefrom for opening the sucking port. The maximum opened position of the sucking valve is regulated by an engagement portion or abutment portion disposed on an inner peripheral surface of the bore. On the valve seat surface of the valve seat plate, at least a portion or area onto which the tip end of sucking valve abuts is finished to have surface roughness of 2 to 3 µmRz, which is extremely flat surface, for sealing between the valve seat plate and the sucking valve. When the swash-plate type compressor is used for example for an air-conditioner of a vehicle, a refrigerant gas is sucked from the sucking chamber to the compressing chamber while the sucking valve is separated from the valve seat plate, and increased pressure of the refrigerant gas generated by movement of the piston causes the sucking valve to abut onto the valve seat surface to thereby close the sucking port.

[0004] By the way, since the refrigerant gas flowing in the compressor contains lubricant oil components therein, the sucking valve and the valve seat surface are exposed in a condition where the above lubricant oil components may attach thereto. As mentioned above, since the abutted area on the valve seat surface is finished into extremely flat condition, the sucking valve such as a reed valve may be adhered to the valve seat surface strongly due to a surface tension of the oil components presented on the abutted area on the valve seat surface, in sucking the refrigerant gas. For this reason, the sucking valve will not open until a negative pressure in the compressing chamber reaches to value over sum of the predetermined valve opening pressure and the surface tension, and simultaneous with opening of the sucking valve the refrigerant gas is introduced into the compressing chamber suddenly. Consequently, an instantaneous variable pressure wave (sucking pulsation) causes noise of a vaporing device as well as a shocking vibration wave due to collision of the sucking valve against the engaged portion provided on the inner surface of the bore, so that the noise in the vehicle is increased.

[0005] In order to solve or overcome above disadvantages, various measures have been prepared. For example, in a swash-plate type compressor disclosed in Japanese Patent Laid-open No. 7-103138, an annular roughed area is formed around an sucking port formed on the valve seat plate to make separation of the sucking valve from the abutted portion easier, so that pressure in the operating chamber is released to the sucking chamber in a condition where the sucking valve is contacted with the valve seat surface. However, above JP '138 has not clearly referred to the sucking pulsation (provided that the above roughed portion is effective to facilitate separation of the sucking valve from the valve seat plate in sucking the gas, the sucking valve will not be separated surely because the roughed portion is formed only around the sucking port).

[0006] In addition, Japanese Patent Laid-open No. 5-99149 discloses a valve apparatus for a compressor in which a shock sucking material made of fluoride resin is provided on the valve seat plate to suck or to damp colliding noise generated in opening/closing the sucking valve and discharging valve between the sucking valve and discharging valve and the valve seats thereof. Japanese Patent Laid-open No. 8-61240 discloses a valve plate apparatus in which an area on a discharging valve or a valve seat plate located outward of a valve seat portion is roughed to avoid attachment of the sucking valve to the valve seat surface due to resistance of an oil film formed between the discharging valve and the valve seat surface.

[0007] On the other hand, some swash-plate type compressor has a spring to reduce the inclined angle of the swash plate for attenuating shock generated in re-starting the compressor when the compressor is stopped. That is, some shock may occur in the compressor if the compressor re-starts, after stoppage thereof, in the condition where inclined angle of the swash plate is still large. The above spring is provided to urge the swash plate toward the minimum inclined state.

[0008] Due to presence of the above spring, if an electro-magnetic clutch is turned off while the compressor is being driven in the maximum capacity condition (maximum inclined condition of the swash plate), the swash plate tends to move or incline from the maximum inclined state to the minimum inclined state by urging force of the spring. Here, it is noted that not only pressures in plural compressing chambers for the pistons just after stoppage of the compressor are respectively different from each other, but these compressing chambers are independent mutually. Accordingly, in spite of urging of the swash plate by the spring, relatively longer time is necessary until all of the pistons in the compressing chamber move up to the predetermined position to bring the swash plate to the minimum inclined state. As a result, if the compressor re-starts in the short time, after stoppage and before the swash plate has not returned to the minimum inclined state, the swash plate begins to rotate in relatively largely inclined state to thereby cause a starting shock.

[0009] Urging force of the spring can be increased when only earlier return of the swash plate to the minimum inclined state is considered, which however hinders or deteriorates the primary operation of the swash plate.

Summary of the Invention

[0010] The present invention is made by taking the above circumstances into consideration, and has a first object to provide the piston-type compressor as well as the swash-plate type compressor in which pulsating of the refrigerant gas upon sucking is restricted, so that various noises such as noise generated at a vaporing device and noise generated by abutment of the sucking valve to the regulating portion thereof are reduced.

[0011] For the above object, in a piston-type compressor including the swash-plate type compressor comprising a casing having a plurality of bores, a plurality of pistons respectively inserted into each of said bore to be moved reciprocately ,a driving means for sequentially moving said pistons to suck refrigerant gas into each bore and to discharge a refrigerant gas therefrom, an sucking valve mechanism disposed at opened portion of the bores and including a valve seat plate on which a plurality of sucking ports are formed and a plurality of sucking valves to open/close each sucking ports, and a discharging valve mechanism disposed at the opened portion of the bores, whole of an abutted area on the valve seat plate onto which the sucking valves abut, or whole of an abutting area on each of the sucking valves to be abutted onto the valve plate is roughed, to facilitate separation of the sucking valve from the valve seat plate in sucking the refrigerant gas into the bores of said casing.

[0012] On account of broadening of the roughed abutted area on the valve seat plate or the roughed abutting area on each sucking valve, in both of the piston type compressor and the swash-plate type compressor, the sucking pulsation of refrigerant gas due to resistance to open the tongue-like sucking valve can be remarkably attenuated, whereby the above various noises can be reduced.

[0013] A second object of the present invention is, in a swash-plate type compressor having a spring for returning the swash plate toward the minimum inclined state during stoppage of the compressor, to attenuate shock which may occur if the compressor is re-started in a short time after stoppage.

[0014] For the above object, in the swash-plate type compressor comprising a casing having a crank chamber and a plurality of bores communicated with the crank chamber at one end thereof, a plurality of pistons respectively inserted into the plurality of bores to be moved reciprocately, a swash plate disposed in the crank chamber for sequentially move said plurality of pistons to suck a refrigerant gas into the bores and to discharge the refrigerant gas therefrom,
   rotary means for rotating said swash plate, a sucking valve mechanism disposed at other end of the bores and including a valve seat plate on which a plurality of sucking ports are formed and a plurality of sucking valves to open/close the sucking ports, and a discharging valve mechanism disposed at the other open end of the bores, whole of an abutted area on the valve seat plate onto which the sucking valve abuts, or whole of an abutting area on each of the sucking valves to be abutted onto the valve plate is roughed, to facilitate separation of the sucking valve from the valve seat plate in sucking the refrigerant gas into the bores of said casing.

[0015] On account of roughing of whole of the abutted area on the valve seat plate or the sucking valve, if the sucking valve is contacted with the valve seat surface when the compressor stops, pressure in the compressing chamber can be released to the sucking chamber through fine or minute gaps formed by roughing, so the swash plate can be returned to the minimum inclined state more quickly to thereby attenuate the shocking.

[0016] The refrigerant gas in the compressing chamber needs to be discharged therefrom for the quick return of the swash plate to the minimum inclined state when the compressor is stopped, but the discharging valve will not open unless the piston moves. The sucking valves are provided primarily to control flow of the refrigerant gas from the sucking chamber to the compressing chamber, if the refrigerant gas, (even if small), can escape between the sucking valve and the valve seat surface during stoppage of the compressor, the swash plate can return to the minimum inclined state easier, correspondingly. Thus, roughing of the abutted area on the valve seat plate or the abutting area on each sucking valve contributes to prevent shocking of the compressor.

BRIEF EXPLANATION OF THE DRAWINGS

[0017] 

Fig. 1 is a cross-sectional view of a swash-plate type compressor to which the present invention is applied;

Fig. 2 is a side view of a valve seat plate in the above embodiment;

Fig. 3 is a side view of an sucking valve plate in the above embodiment;

Fig. 4 is explanatory view showing relation between a reed valve on a valve plate, and an sucking port and a discharging port on the valve seat plate;

Fig. 5 is an enlarged view of Fig. 1 and showing relation among the reed valve of the valve seat plate, the bone of cylinder block and the valve seat surface of the valve seat plate; and

Fig. 6 is a graph showing relation between a roughed area on the valve seat surface and an sucking pulsation of refrigerant gas.

Fig. 7 is a side view of an sucking valve plate in the another embodiment.

Preferred Embodiment of the Invention

[0018] Next, an embodiment in which the present invention is applied to a swash-plate type compressor will be explained with reference to attached drawings.

[0019] The swash-plate type compressor shown in Fig. 1 has a swash plate 30, rotor 25, valve seat plate 40, and valve plates 45 and 50 disposed in a cylinder block 10, front housing 12 and rear housing 13.

[0020] The cylinder block 10 has a plurality of bores (pressure chambers) 11 extending axially and located on a common circle, into each of which a piston 15 is inserted to be moved reciprocately. A front end surface of the cylinder block 10 is closed by the front housing 12, while a rear end surface thereof is closed by the rear housing 13 via the valve seat plate 40 and the sucking or discharging valve plate 45 or 50, and they are connected to each other by a bolt 14 extending threrethrough. In a crank chamber 16 defined by the cylinder block 10 and the front housing 12, a driving shaft 17 extending axially is disposed, each end of which is rotatably supported by the cylinder block 10 and the front housing 12 via bearings 18 and 19, respectively. A sealing member 21 is disposed between the driving shaft 17 and the front housing 12. A front end of the driving shaft 17 is connected to an engine of vehicle via an electro-magnetic clutch and transmission mechanism (not shown).

[0021] In the crank chamber 16, the rotor 25 is mounted on the driving shaft 17 to be rotated synchronously therewith, and a bearing 22 is disposed between the rotor 25 and the front housing 12. The rotor 25 has a pair of arms (only one of which is shown) 26 extending toward the swash plate 30, which will be explained in detail later.

[0022] At rearward (rightward in Fig. 1) of the rotor 25, the swash plate 30 is mounted on the driving shaft 17 via a throughhole 30a configured to allow inclination of the swash plate 30 on the driving shaft 17. The swash plate 30 has at an intermediate portion in radial direction a pair of blakets 27 and a counter-weight 31, and has sliding surfaces 30b at an outer periphery thereof.

[0023] In detail, at the intermediate portion on a front surface of the swash plate 30 facing the rotor 25, the paired blakets 27 are protrudedly provided to be spanned over a top dead center T of the swash plate 30, and at a top end of a guide pin 28 a base end of which is fixed to each blaket 27, a spherical portion 29 is formed. The blaket 27, guide pin 28 and spherical portion 29 form a part of a hinge mechanism K.

[0024] On an area of the front surface of the swash plate 30 corresponding to a bottom dead center, the counter-weight 31 extending radially outwardly from the driving shaft 17 and covering the sliding surface 30b is mounted. The maximum inclined angle of the swash plate 30 is regulated by abutment of an front end surface 30c thereof located nearer to the driving shaft 17 than the counter-weight 31 against a rear end surface 25a of the rotor 25, while the minimum inclined angle of the awash plate 30 is regulated by abutment of a grooved portion 30d at the rear end surface thereof against circle lip 32 mounted on the driving shaft 17. Such inclination is allowed by the through-hole 30a.

[0025] The swash plate 30 is urged rearwardly to reduce the inclined angle by a compression spring 33 disposed between a central portion of the swash plate 30 and a corresponding portion of the rotor 25.

[0026] The above paired supporting arms 26 of the rotor 25 are provided at an upper portion thereof to protrude axially rearwardly to be aligned with the guide pin 28, and having the guiding hole 26a at a tip end thereof which is so designed to extend parallel to a plane defined by an axis of the driving shaft 17 and the top dead center T of the awash plate 30, and to extend radially inwardly toward the driving shaft 17. Thus, the top dead center T of the piston 15 is maintained at the predetermined constant position regardless of variation of the inclined angle the swash plate 30. The spherical portion 29 of the above guide pin 28 is slidably inserted into the guiding hole 26a. Thus, the supporting arms 26 form rest of the hinge mechanism K.

[0027] Against the plain and circular sliding surfaces 30b formed on the both surfaces of the outer peripheral portion of the swash plate 30, shoes 34 of half spherical configuration are respectively abutted, and a convex surface of the shoes 34 are engaged with a concave surface of the piston 15.

[0028] A sucking chamber 35 is formed at a central portion of the rear housing 13 and discharging chambers 36 are formed therearound, and the sucking ports 41 and discharging ports 42 are formed on the valve seat plate 40 corresponding to the bores 11 of the cylinder block 10 to be connected with the sucking chamber 35 and the discharging chamber 36. One surface 40a of the valve seat plate 40 forms an sucking valve seat surface, while the other surface 40b forms a discharging valve seat surface. The sucking port 41 is opened/closed by an sucking (reed) valve 46 on the sucking valve plate 45 disposed at one side of the valve seat plate 40, while the discharging port 42 is opened/closed by a discharging valve 51 on the discharge valve plate 50 disposed at the other side of the valve seat plate 40. The crank chamber 16 and the sucking chamber 35 are communicated with each other by a passage 39 with a diameter-reduced portion.

[0029] Constructions and operation of the discharging valve 51 is substantially same as that of the conventional art, so the sucking valve 46 will be explained in detail hereinafter.

[0030] The valve seat plate 40 and the sucking valve plate 45 will be explained with reference to Figs. 2 to 5. As shown in Fig. 2, on the surface 40a of circular valve seat plate 40, the triangular sucking ports 41 and the circular discharging ports 42 are formed inwardly and outwardly in the radial direction to be communicated with the bore 11 of the cylinder block 10. An outer peripheral portion 40a1 of the sucking valve seat surface 40a to be nipped by the peripheral portion of the bore 11 of the cylinder block 10 and the rear housing 13, and portions 40a2 located between the adjacent sucking ports 41 and discharging ports 42 in the annular portion slightly retracted inwardly from the outermost periphery of the valve seat plate 40, are finished in extremely flat condition to have surface roughness of 2 to 3 µmRz.

[0031] To the contrary, whole of the abutted or contacted portion 43 including the sucking ports 41 and the discharging ports 42 are roughed, as dotted. That is, in addition to a portion 43a of the abutted portion 43 to which the portion 46a of the reed valve 46 abuts and which is located around the sucking port 41, an intermediate portion 43b and a base portion 43c of the abutted portion 43 to which the intermediate portion 46b or the base portion 46c of the reed valve 46 respectively abuts are roughed in the same way to have surface roughness of 15 to 30 µmRz. For the surface roughing, shot blast, grinding or knurling can be used, and in using the shot blast the portions or areas on the valve seat surface 40a need not be roughed are masked.

[0032] As shown in Fig. 3, in the sucking valve plate 45 made of circular thin plate, reed valves 46 of the same numbers as that of the bore 11 and extending radially outwardly are formed by forming a U-shaped throughhole 47. A portion 46a near to the tip end of the valve plate 45 abuts the portion of the valve seat plate 40 around the sucking port 41, and an elongate hole 48 extending from the intermediate portion 46b to the base portion 46c of the valve plate 45 include or overlap with the discharging port 42 so as not to hinder discharge of the compressed refrigerant gas therethrough.

[0033] Fig. 4 shows a relation among the bore 11 of the cylinder block 10, the sucking port 41, discharging port 42, roughed area (abutted portion) 43, and the reed valve 46 of the sucking valve plate 45. As shown in Fig. 5, the frontmost portion 46d of the reed valve 46 can engage an engaged portion 11a formed on an inner peripheral surface of the bore 11 to regulate degree of opening of the reed valve 46.

[0034] As mentioned above, in the present embodiment, not only the elongate hole 48 is formed on the reed valve 46 over the base portion 46c and the flex portion 46b, but whole of the butted portion 43 on the valve seat surface 40a of the valve seat plate 40 is deeply roughed. Formation of the elongate hole 48 on the reed valve 46 allows flowing of the refregirant gas to the discharging chamber 35 through the discharging port 42, reduces the contacted area between the reed valve 46 and the abutted portion 43, and reduces bending rigidity of the reed valve 46 without reducing the twisting moment. In addition, whole of the abutted area 43 on the valve seat surface 40a is roughed to form multiple minute or fine gaps between the reed valve 46 and the valve seat surface 40a, so that substantial contacting area therebetween is greatly reduced.

[0035] As a result, in the sucking step of the refrigerant gas performed by leftwardly movement of the piston 15, even if the oil film of lubricant oil presents between the reed valve 46 and the abutted portion 43, the surface tension (resistance to open the valve) can be remarkably reduced, so that the reed valve 46 can be separated away from the abutted portion 43 easily and vibration of the reed valve 46 can be restricted effectively.

[0036] That is, according to the experiment by inventors of the present application, as apparent from Fig. 6 which shows relation between rate of the roughed area on the valve seat surface 40a and the sucking pulsation, it is confirmed that level of the sucking pulsation due to the resist to valve opening of the reed valve 46 is gradually decreased, as the roughed area is broadened from a top portion 43a around the sucking port 41 and to which the top portion 46a of the reed valve 46 abuts, to the intermediate portion 43b and base portion 43c to which the intermediate portion 46b and the base portion 46c of the reed valve 46 abut respectively. Accordingly, even if the electro-magnetic clutch is turned off during operation of the compressor in the maximum capacity condition, and the compressor is re-started in the short time with maintaining relatively large inclined angle of the swash plate 30, noise of the vaporing device caused by sucking pulsation with instantenous vibrating pressure wave and colliding vibration wave between the engaging portion formed on the inner peripheral surface of the bore 11 and the tip end of the tongue-like reed valve 46 are suitably damped. Thus, the noises can be attenuated.

[0037] Meanwhile, it is noted that small amount of the refrigerant gas leaks through the roughed area 43 to the sucking chamber 35 in the compressing process of the piston 15, so the abutted area 43 should not be largely roughed over the predetermined level, taking decrease of the resistance to open the valve seriously. The abutted portion 43 having roughness of 15 to 30 µmRz is preferable both to facilitate separation of the reed valve 46 from the abutted portion 43 and to prevent leakage of gas to the sucking chamber 35 therethough in the sucking process.

[0038] Attention should be paid that leakage of the refrigerant gas through the roughed area 43 to the sucking chamber 35 can promote return of the swash plate 30 to the minimum inclined state, when the compressor is stopped. That is, if the reed valve 46 is maintained in the abutted state onto the abutted portion 43 when the compressor is stopped, pressure is released from the compressing chamber to the sucking chamber 35 through the fine gaps formed by roughing , which makes return or movement of the pistons 15 in the bores 11 easier.

[0039] Another embodiment of the present invention is shown in Fig. 7, in which, instead of roughing of the abutted portion 43 on the valve seat surface 40a, whole of an abutting surface 57 of each of the reed valves 56 to be abutted onto the valve seat surface 40a is roughed. In detail, whole of surface of the reed valve 56 facing the valve seat surface 40a including a base portion 56c, a flex portion 56b and a tip portion 56 is roughed except for the U-shaped throughhole 47 and the elongate hole 48 to have the surface roughness of 15 to 30 µmRz (valve seat surface 40a is not roughed). According to this embodiment, the advantage equivalent to that of the above embodiment can be obtained. Thus, the abutted portion on the valve seat surface or the abutting portion on the reed valve can be selectively roughed by considering the surface finishing technique or the manufacturing cost of the sucking valve mechanism.

Claims

1. A piston-type compressor comprising a casing (10,12,13) having a plurality of bores(11), a plurality of pistons(15) respectively inserted into each of said bore to be moved reciprocately, a driving means (25,30) for sequentially moving said pistons to suck a gas into each bore and to discharge the gas therefrom, an sucking valve mechanism (40,45) disposed at opened portion of the bores and including a valve seat plate (40) on which a plurality of sucking ports (41) are formed and a plurality of sucking valves (46) to open/close each of the sucking ports, and a discharging valve mechanism (40,50) disposed at the opened portion of the bores,
   characterized by that in said sucking valve mechanism, whole of an abutted area (43) on the valve seat plate (40) onto which the sucking valves(46) abut, or whole of an abutting area (57) on each of the sucking valves to be abutted onto the valve seat plate is roughed, to facilitate separation of the reed valve from the valve seat plate in sucking the gas into the bores of said casing.

2. A piston-type compressor according to claim 1, wherein whole of an abutted area (43) on the valve seat plate onto which the sucking valves abut is roughed.

3. A piston-type compressor according to claim 2, wherein the abutted area (43) on said valve seat plate includes a peripheral portion (43a1) of sucking ports with which a tip end of the sucking valve contacts, and an intermediate portion (43a2) in a radial direction with which a flexed portion of the sucking valve contacts.

4. A piston-type compressor according to claim 3, wherein the each of the sucking ports (41) on the valve seat plate has a triangular shape a top of which is directed to a center of the valve seat plate.

5. A piston-type compressor according to claim 1, wherein a throughhole (47) is formed on each of the sucking valves.

6. A piston-type compressor according to claim 5, wherein discharging ports (42) are formed on the valve seat plate to be overlapped with the throughhole of each of the sucking valves.

7. A piston-type compressor according to claim 5, wherein whole of an abutting area (57) on each of the sucking valves to be abutted onto the valve seat plate is roughed.

8. A piston-type compressor according to claim 1, wherein the abutted area on the valve seat plate or the abutting area on each of the sucking valves has a surface roughness of 15 to 30 µmRz.

9. A swash plate type compressor comprising a casing (10,12,13) having a crank chamber (16) and a plurality of bores (11) communicated with the crank chamber at one end thereof, a plurality of pistons (15) respectively inserted into the plurality of bores to be moved reciprocately, a swash plate (30) disposed in the crank chamber for sequentially move said plurality of pistons to suck a gas into the bores and to discharge the gas therefrom, rotary means (25) for rotating said swash plate, an sucking valve mechanism (40,45) disposed at other end of the bores and including a valve seat plate on which a plurality of sucking ports are formed and a plurality of sucking valves to open/close each of the sucking ports, and a discharging valve mechanism (40,50) disposed at the other open end of the bores,
   characterized by that in said sucking valve mechanism, whole of an abutted area (43) on the valve seat plate (40) onto which the sucking valves abut, or whole of an abutting area (57) on each of the sucking valves to be abutted onto the valve seat plate is roughed, to facilitate separation of the sucking valve from the valve seat plate in sucking the gas into the bores of said casing.

10. A swash-plate type compressor according to claim 9, wherein a throughhole (47) is formed on each of the sucking valves.

11. A swash-plate type compressor according to claim 11, wherein discharge ports (42) are formed on the valve seat plate to be overlapped with the throughhole of each of the sucking valves.

12. A swash-plate type compressor according to claim 9, wherein roughed abutted area on the valve seat plate or the abutting area on each of the sucking valves has a surface roughness of 15 to 30 µmRz.

13. A swash-plate type compressor according to claim 9, further comprising a capacity return spring for urging the swash plate in a direction to have smaller inclined angle.

Drawing