Abstract:
Discharge holes and suction holes having shapes that suppress the turbulence of a refrigerant gas flow are disclosed. The shape of the discharge hole according to the present invention has a tapered surface wall, such that the circumference of the discharge hole increases from the piston cylinder surface to the discharge chamber surface. Similarly, the shape of the suction hole according to the present invention has a tapered surface wall such that the circumference of the suction hole increases from the suction chamber surface to the piston cylinder surface. The present invention allows the flow path of the refrigerant gas to flow approximately tangential to the valve reed by providing a tapered surface wall. The flow resistance of the discharge hole or the suction hole is reduced such that the volume efficiency of the compressor is improved and compressor noise is suppressed.

Description:
This is a continuation-in-part patent application of Ser. No. 09/213,254, filed on Dec. 17, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a refrigerant compressor used for an automotive air-conditioning system. More particularly, the present invention relates to shapes of suction holes and discharge holes provided in a valve plate of a compressor. 
     2. Description of the Related At 
     A description of the structure and operation of a refrigerant compressor for an automotive air conditioning system follows. Referring to FIG. 1, a conventional compressor  100  is depicted. Compressor  100  comprises front housing  30 , housing  27 , valve plate  1 , and rear housing  32 . Along the central axis of compressor  100  is provided a drive shaft  34 , which is supported rotatably by needle bearings  35  and  36 . Within housing  27 , cam rotor  37  which is fixed to drive shaft  34  engages the inner wall of front housing  30  via thrust bearing  38 . Cam rotor  37  rotates when drive shaft  34  is rotated. Hinge mechanism  39  couples cam rotor  37  with inclined plate  40 . Inclined plate  40  rotates with cam rotor  37 . Wobble plate  43  engages with inclined plate  40  via thrust bearing  41  and needle bearing  42 . A wobbling motion is induced in inclined plate  40 , so that inclined plate  40  wobbles while rotating. This motion of inclined plate  40  transfers to wobble plate  43 . Rotation of wobble plate  43  is inhibited by engagement with a guide bar  44 . Therefore, only the wobbling component of the motion of inclined plate  40  is transferred from inclined plate  40  to wobble plate  43 . Wobble plate  43  has a wobbling motion, but does not rotate with drive shaft  34 . Rod  45  is connected by spherical coupling to wobble plate  43  and to a plurality of pistons  46 . When wobble plate  43  wobbles, each of pistons  46  reciprocates in one of a plurality of cylinders  71 . 
     Suction valve reed  22 , discharge valve reed  2 , and valve retainer  3  are fixed by bolt  47  to valve plate  1 . Suction holes  5  and discharge holes  4  correspond to each piston cylinder  71 . Suction chamber  72  and discharge chamber  70  are formed by valve plate  1  and the rear housing  32 , and are separated by inside partition plate  33 . 
     When drive shaft  34  is rotated by an external power source (not shown), each piston  46  reciprocates in its respective piston cylinder  71 . When piston  46  is moving leftward in FIG. 1, the suction phase is executed, and when piston  46  is moving rightward, the compression phase is executed. 
     In the suction phase, refrigerant gas in suction chamber  72  is drawn into piston cylinder  71  through suction hole  5 . Due to the pressure variance between suction chamber  72  and piston cylinder  71 , the refrigerant gas in suction chamber  72  flows to suction hole  5 , passes through suction hole  5 , opens suction valve reed  22 , and enters piston cylinder  71 . Suction valve reed  22  prohibits a reverse flow of refrigerant gas into suction chamber  72  during the compression phase. 
     In the compression phase, the refrigerant gas in piston cylinder  71  is discharged into discharge chamber  70  through discharge hole  4 . Due to the pressure variance between piston cylinder  71  and discharge chamber  70 , the refrigerant gas passes through discharge hole  4 , opens discharge valve reed  2 , and enters discharge chamber  70 . Discharge valve reed  2  prohibits a reverse flow of the refrigerant gas into piston cylinder  71  during the suction phase. 
     FIG. 2 a  depicts a cross-sectional view of valve plate  1  from the rear housing side of valve plate  1 . FIG. 2 b  depicts a cross-sectional view of valve plate  1  from the cylinder head side of valve plate  1 . With reference to FIG. 2 a , rear housing  32  is fixed to housing  27  by a plurality of bolts  130 . Suction holes  5  and discharge holes  4  are disposed equiangularly around the center CO and correspond to piston cylinders  71 . Suction chamber  72  and discharge chamber  70  are separated by inside partition plate  33 . Discharge valve reed  2  within inside partition plate  33  is substantially star-shaped. The arms of discharge valve reed  2  cover discharge holes  4 . With reference to FIG. 2 b , suction valve reed  22  also is substantially star-shaped. Within each arm, a hole  22   h  enables the discharge gas to flow therethrough. 
     FIG. 3 depicts valve plate  1  as viewed from the side of valve plate  1  facing discharge chamber  70 . Discharge holes  4  and suction holes  5  are disposed equiangularly with respect to the center C of valve plate  1 . FIG.  4  and FIG. 5 are corresponding radial, cross- sectional views of valve plate  1  of FIG.  1 . Valve reed  2  is fixed between valve plate  1  and valve retainer  3 . Discharge holes  4  have side walls which are substantially perpendicular to the opposing surfaces of valve plate  1 . 
     FIG.  4  and FIG. 5 depict valve plate  1  during the compression phase. When the refrigerant gas is discharged from cylinders  71 , it strikes, pushes, and displaces valve reed  2 . The refrigerant gas flows into discharge chamber  70  through a gap created between valve reed  2  and valve plate  1 . When refrigerant gas flow impinges against reed valve  2  in FIG. 4, its flow path may be diverted at an angle substantially perpendicular to valve plate  1 . Turbulence in the refrigerant gas flow may be created due to the abrupt change in the direction of flow. Further, a portion of the refrigerant gas flow impinging against valve reed  2  may not enter discharge chamber  70 , and may instead return to piston cylinder  71 . These turbulence effects are indicated by the arrows in FIG.  4  and FIG.  5 . Therefore, turbulence of the refrigerant gas flow may result in flow resistance at discharge hole  4 . Such flow resistance lowers the volumetric efficiency, a primary measure of the performance of compressor  100 . The turbulence of flow also disturbs the motion of valve reed  2  and impedes valve reed  2  from discretely and completely opening and closing. Moreover, the turbulence of flow in discharge holes  4  may cause noise in compressor  100 . Similar problems may occur with respect to suction holes  5 . 
     Thus, it has long been desired to resolve effectively the problem of the turbulence of refrigerant gas flowing through the suction holes and discharge holes and to suppress noise generated thereby. 
     SUMMARY OF THE INVENTION 
     Therefore, a need has arisen to effectively resolve the problem of turbulence of refrigerant gas flowing through the suction holes and discharge holes, so that refrigerant flow is not impeded, and noise is suppressed. It is an object of the present invention to provide a shape for such suction holes and discharge holes in a valve plate of a compressor that improves the volumetric efficiency of the compressor and suppresses noise. It is another object of the present invention to provide shapes of such suction holes and discharge holes that may suppress the occurrence of turbulence of the refrigerant gas flow to lower impedance to refrigerant gas passing through the suction holes or the discharge holes, or both. 
     A compressor according to the present invention is equipped with a valve plate that has suction passages and discharge passages. Regarding the discharge passages, each of the discharge passages includes a first piston cylinder-side opening having a first piston cylinder-side opening area, a discharge chamber-side opening having a discharge chamber-side opening area, and a sidewall extending between the openings. At least a portion of the discharge passage sidewall is tapered. The discharge chamber-side opening area is greater than the piston cylinder-side opening area. Regarding the suction passages, each of the suction passages includes a second piston cylinder-side opening having a second piston cylinder-side opening area, a suction chamber-side opening having a suction chamber-side opening area, and a sidewall extending between the openings. At least a portion of the suction passage sidewall is tapered. The piston cylinder-side opening area is greater than the suction chamber-side opening area. The sidewalls of the passages may include a substantially cylindrical portion. Further, the tapered portion of the sidewalls of the passages may be less than the thickness of the valve plate. Even with partial tapering, the objects of the present invention may be achieved. 
     Along the tapered sidewalls of suction holes or discharge holes, or both, the flow path of the refrigerant gas may bend gradually. The flow path of the refrigerant gas does not strike the valve reed perpendicularly, but instead flows along the tapered portion of the sidewall. As a result, any turbulence of the refrigerant is reduced in the suction holes or discharge holes, so that the volumetric efficiency of the compressor may be improved and associated noise suppressed. 
     Other objects, features, and advantages of this invention will be understood from the following detailed description of the preferred embodiment of this invention with reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts. 
     FIG. 1 is a cross-sectional view of a conventional compressor. 
     FIG. 2 a  is a cross-sectional view along line II a —II a  depicted in FIG.  1 . 
     FIG. 2 b  is a cross-sectional view along line II b —II b  depicted in FIG.  1 . 
     FIG. 3 is a plan view of a valve plate according to the compressor of FIG.  1 . 
     FIG. 4 is a cross-sectional view along line IV—IV of the valve plate depicted in FIG.  3 . 
     FIG. 5 is a cross-sectional view along line V—V of the valve plate depicted in FIG.  3 . 
     FIG. 6 is a plan view of a valve plate according to an embodiment of the present invention. 
     FIG. 7 is a cross-sectional view along line VII—VII of the valve plate depicted in FIG.  6 . 
     FIG. 8 is a cross-sectional view along line VIII—VIII of the valve plate depicted in FIG.  6 . 
     FIG. 9 is a partial plan view of the discharge hole depicted in FIG.  6 . 
     FIG. 10 is a plan view of a valve plate according to another embodiment of the present invention. 
     FIG. 11 is a cross-sectional view along line XI—XI of the valve plate depicted in FIG.  10 . 
     FIG. 12 is a cross-sectional view along line XII—XII of the valve plate depicted in FIG.  10 . 
     FIG. 13 is a partial plan view of the discharge hole depicted in FIG.  10 . 
     FIG. 14 is a plan view of a valve plate according to another embodiment of the present invention. 
     FIG. 15 is a cross-sectional view along line XV—XV of the valve plate depicted in FIG.  14 . 
     FIG. 16 is a cross-sectional view along line XVI—XVI of the valve plate depicted in FIG.  14 . 
     FIG. 17 is a partial plan view of the discharge hole depicted in FIG.  14 . 
     FIG. 18 is a plan view of a valve plate according to another embodiment of the present invention. 
     FIG. 19 is a cross-sectional view along line XIX—XIX of the valve plate depicted in FIG.  18 . 
     FIG. 20 is a cross-sectional view along line XX—XX of the valve plate depicted in FIG.  18 . 
     FIG. 21 is a partial plan view of the discharge hole depicted in FIG.  18 . 
     FIG. 22 is a plan view of a valve plate according to another embodiment of the present invention. 
     FIG. 23 is a cross-sectional view alone line XXIII—XXIII of the valve plate depicted in FIG.  22 . 
     FIG. 24 is a cross-sectional view along line XXIV—XXIV of the valve plate depicted in FIG.  22 . 
     FIG. 25 is a partial plan view of the discharge hole depicted in FIG.  22 . 
     FIG. 26 is a plan view of a valve plate according to another embodiment of the present invention. 
     FIG. 27 is a cross-sectional view alone line XXVII—XXVII of the valve plate depicted in FIG.  26 . 
     FIG. 28 is a cross-sectional view along line XXVIII—XXVIII of the valve plate depicted in FIG.  26 . 
     FIG. 29 is a partial plan view of the discharge hole depicted in FIG.  26 . 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Embodiments of the present invention are illustrated in FIGS. 6-29, wherein like numerals are used to denote elements that correspond to like elements depicted in FIGS. 6-29. A detailed explanation of several elements and characteristics of related art compressors has been provided above and, therefore, is here omitted. 
     Referring to FIG. 6, a plan view of a valve plate  11  from discharge chamber  70  in accordance to an embodiment of the present invention is depicted. Discharge holes  14  and suction holes  15  are disposed equiangularly in valve plate  11  with respect to center C. FIGS. 7 and 8 are cross-sectional views of the discharge mechanism during a compression phase. Valve reed  12  is fixed between valve plate  11  and valve retainer  13 . A sidewall  16  of discharge hole  14  is formed as a convex tapered surface. Small circular opening  16   a  is on the piston cylinder end of sidewall  16 . Large circular opening  16   b  is on the discharge chamber end of sidewall  16 . Referring to FIG. 9, hole area Sa is defined by small circular opening  16   a , and hole area Sb is defined by large circular opening  16   b.    
     In an embodiment of the present invention, area Sb is about 1.5 times greater than area Sa. The curve of sidewall  16  allows area Sa on the piston cylinder-side surface of valve plate  11  to increase gradually to area Sb on the discharge chamber-side surface of valve plate  11 . Thus, the circumference of discharge hole  14  increases from the piston cylinder-side surface to the discharge chamber-side surface of valve plate  11 . According to the present invention, a viscous fluid that flows near a wall of a chamber, or tube, flows along the surface. Being a viscous fluid, the refrigerant gas flows along sidewall  16  when discharge hole  14  is open, as indicated by the arrows in FIG.  7  and FIG.  8 . The direction of flow of the refrigerant gas gradually bends in a lateral direction according to FIGS. 7 and 8. The refrigerant gas is prevented from colliding directly upon valve reed  12 . As a result, turbulence of the refrigerant gas within discharge hole  14  is reduced. Therefore, the shape of discharge hole  14  improves the volumetric efficiency of compressor  100 . 
     FIGS. 10-13 depict another embodiment of the present invention. Referring to FIG. 10, a plan view of valve plate  11  from the discharge chamber-side is depicted. Discharge holes  14 ′ and suction holes  15  are disposed equiangularly in valve plate  11  with respect to the center C. FIGS. 11 and 12 depict the cross-sectional views of the discharge mechanism during the compression phase. Valve reed  12  is fixed between valve plate  11  and valve retainer  13 . Discharge hole  14 ′ includes partially convex sidewall  16 ′ and cylindrical portion  19 ′. Small circular opening  16   a ′ is the piston cylinder-end circumference of sidewall  16 ′. Large elliptical opening  16   b ′ is the discharge chamber-end opening of sidewall  16 ′. 
     In this embodiment, large elliptical opening  16   b ′ extends to only the radially outer side of discharge hole  14 ′ with respect to center C of valve plate  11 . Referring to FIG. 13, hole area Sa′ is defined by small circular opening  16   a ′, and hole area Sb′ is defined by large elliptical opening  16   b ′. In this embodiment, area Sb′ is about 1.5 times greater than area Sa′ . The curve of partially tapered sidewall  16 ′ allows area Sa′ on the piston cylinder-side surface of valve plate  11  to increase gradually to area Sb′ on the discharge chamber-side surface of valve plate  11 . Thus, the circumference of discharge hole  14 ′ increases from the piston cylinder-side surface to the discharge chamber-side surface of valve plate  11 . 
     FIGS. 14-17 depict another embodiment of the present invention. Referring to FIG. 14, a plan view of valve plate  11  from the discharge chamber side is depicted. Discharge holes  14 ″ and suction holes  15  are disposed equiangularly in valve plate  11  with respect to the center C. On the surface of valve plate  11 , valve seat grooves  110  are provided around each discharge hole  14 ″. Valve seat groove  110  prevents valve reed  12  from sticking to valve plate  11 . 
     FIGS. 15 and 16 depict the cross-sectional view of the discharge mechanism during the compression phase. Valve reed  12  is fixed between valve plate  11  and valve retainer  13 . Discharge hole  14 ″ comprises a tapered sidewall  16 ″ and a perpendicular part  17 ″. Small circular opening  16   a ″ is the piston cylinder-end opening of perpendicular part  17 ″. Large circular opening  16   b ″ is the discharge chamber-end opening of sidewall  16 ″. 
     Referring to FIG. 17, opening area Sa″ is defined by small circular opening  16   a ″, and opening area Sb″ is defined by large circular opening  16   b ″. In this embodiment, area Sb″ is approximately 1.5 times greater than area Sa″. Therefore, tapered sidewall  16 ″ allows area Sa″ on the piston cylinder-side surface of valve plate  11  to increase gradually to area Sb″ on the discharge chamber-side surface of valve plate  11 . Further, with reference to FIG. 16, the height of perpendicular part  17 ″ is greater than or equal to zero. 
     FIGS. 18-21 depict another embodiment of the present invention. Referring to FIG. 18, a plan view of valve plate  11  seen from the discharge chamber-side is depicted. Discharge holes  14 ′″ and suction holes  15  are disposed equiangularly in valve plate  11  with respect to center C. FIGS. 19 and 20 depict the cross-sectional view of the discharge mechanism during the compression phase. Valve reed  12  is fixed between valve plate  11  and valve retainer  13 . Discharge hole  14 ′″ comprises a partially tapered sidewall  16 ′″, a cylindrical portion  19 ′″ and a perpendicular part  17 ′″. Small circular opening  16   a ′″ is the piston cylinder- end opening of perpendicular part  17 ′″. Large elliptical opening  16   b ′″ is the discharge chamber-end opening of tapered sidewall  16 ′″. 
     In this embodiment, large elliptical opening  16   b ′″ extends to the radially outer side of discharge hole  14 ′″ with respect to center C of valve plate  11 . Referring to FIG. 21, opening area Sa′″ is defined by small circular opening  16   a ′″, and opening area Sb′″ is defined by large elliptical opening  16   b ′″. In this embodiment, area Sb′″ is about 1.5 times greater than area Sa′″. Therefore, partially tapered sidewall  16 ′″ allows area Sa′″ on the piston cylinder- side surface of valve plate  11  to increase gradually to area Sb′″ on the discharge chamber-side surface of valve plate  11 . 
     FIGS. 22-25 depict another embodiment of the present invention. Referring to FIG. 22, a plan view of valve plate  11  from the discharge chamber side is depicted. Discharge holes  14 ″″ and suction holes  15  are disposed equiangularly in valve plate  11  with respect to the center C. On the surface of valve plate  11 , valve seat grooves  110  are provided around each discharge hole  14 ″″. Valve seat groove  110  prevents valve reed  12  from sticking to valve plate  11 . 
     FIGS. 23 and 24 depict the cross-sectional view of the discharge mechanism during the compression phase. Valve reed  12  is fixed between valve plate  11  and valve retainer  13 . Discharge hole  14 ″″ comprises a tapered sidewall  16 ″″, a piston cylinder-side perpendicular straight part  17 ″″ and a discharge chamber-side perpendicular straight port  18 ″″. Small circular opening  16   a ″″ is the piston cylinder-end opening of perpendicular part  17 ″″. Large circular opening  16   b ″″ is the discharge chamber-end opening of perpendicular port  18 ″″. The axial length of each of perpendicular ports  17 ″″ and  18 ″″ is designed not to affect the gas flow through discharge hole  14 ″″. 
     Referring to FIG. 25, opening area Sa″″ is defined by small circular opening  16   a ″″, and opening area Sb″″ is defined by large circular opening  16   b ″″. In this embodiment, area Sb″″ is approximately 1.5 times greater than area Sa″″. Therefore, tapered sidewall  16 ″″ allows area Sa″″ on the piston cylinder-side surface of valve plate  11  to increase gradually to area Sb″″ on the discharge chamber-side surface of valve plate  11 . 
     In this embodiment, because axially straight portions  17 ″″ and  18 ″″ perpendicular to the respective surfaces of value plate  11  at positions respective adjacent to the respective surfaces of value plate  11 , at an appropriate axial length, even if the surfaces of value plate  11  are ground after forming discharge hole  14 ″″, the sectional shape and the diameter of discharge hole  14 ″″ may not charge. Even if an inclined surface is formed as the surface of value plate″ by grinding, the sectional shape and the diameter of discharge hole  14 ″″ substantially may not change. Consequently, the control of the dimensions may be easy, the quality of value plate  11  may be stabilized, and the quality of the compressor may be improved. 
     FIGS. 26-29 depict another embodiment of the present invention. Referring to FIG. 26, a plan view of valve plate  21  from the piston cylinder-side is depicted. Discharge holes  24  and suction holes  25  are disposed equiangularly in valve plate  21  with respect to the center C. FIGS. 27 and 28 depict the cross-sectional view of the suction mechanism during the suction phase. With reference to FIG. 27, vibration of valve reed  22  is limited by a groove  23  provided at end of housing  27 . Suction hole  25  includes a convex tapered sidewall  26 . Small circular opening  26   a  is the suction chamber-end opening of tapered sidewall  26 . Large circular opening  26   b  is the piston cylinder-end opening of tapered sidewall  26 . 
     Referring to FIG. 29, opening area S 2   a  is defined by small circular opening  26   a , and opening area S 2   b  is defined by large circular opening  26   b . In this embodiment, area S 2   b  is about 1.5 times greater than area S 2   a . The curve of convex tapered sidewall  26  allows area S 2   a  on the suction chamber-side surface of valve plate  21  to increase gradually to area S 2   b  on the piston cylinder-side surface of valve plate  21 . Thus, the circumference of suction hole  25  increases from the suction chamber-side surface of valve plate  21  to the piston cylinder surface. The shapes of the holes depicted in FIGS. 6-25 and described with respect to discharge holes are applicable to and suitable for suction holes. 
     Thus, the present invention provides a convex tapered sidewall or a tapered sidewall with cylindrical portions in a discharge hole or in a suction hole, or both. As a result, the turbulence of the refrigerant flow passing through the discharge holes or the suction holes, or both, may be reduced. Accordingly, the flow resistance for the refrigerant gas through the discharge holes and suction holes decreases, so that the volumetric efficiency of the compressor may be improved and related noise suppressed. 
     The present invention is applicable to any type of compressor that has a reed valve mechanism. For example, the present invention may be applied to swash plate-type compressors, wobble plate-type compressor, scroll-type compressor, or rotary-type compressor. Although the present invention has been described in detail in connection with preferred embodiments, the invention is not limited thereto. It will be understood by those of ordinary skill in the art that variations and modifications may be made within the scope of this invention, as defined by the following claims.