US20030035732A1 - Structure of channel in variable displacement piston type compressor - Google Patents
Structure of channel in variable displacement piston type compressor Download PDFInfo
- Publication number
- US20030035732A1 US20030035732A1 US10/215,702 US21570202A US2003035732A1 US 20030035732 A1 US20030035732 A1 US 20030035732A1 US 21570202 A US21570202 A US 21570202A US 2003035732 A1 US2003035732 A1 US 2003035732A1
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- United States
- Prior art keywords
- drive shaft
- chamber
- cylinder block
- bleed passage
- variable displacement
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000006073 displacement reaction Methods 0.000 title claims abstract description 50
- 239000003507 refrigerant Substances 0.000 claims abstract description 66
- 230000000903 blocking effect Effects 0.000 claims description 39
- 239000000314 lubricant Substances 0.000 claims description 10
- 229920001971 elastomer Polymers 0.000 claims description 7
- 239000005060 rubber Substances 0.000 claims description 7
- 229920000459 Nitrile rubber Polymers 0.000 claims description 3
- -1 polytetrafluoroethylene Polymers 0.000 claims description 3
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 3
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 3
- 229920005989 resin Polymers 0.000 claims 2
- 239000011347 resin Substances 0.000 claims 2
- 238000011144 upstream manufacturing Methods 0.000 claims 2
- 239000012530 fluid Substances 0.000 claims 1
- 230000004308 accommodation Effects 0.000 description 20
- 230000006835 compression Effects 0.000 description 9
- 238000007906 compression Methods 0.000 description 9
- 229920003002 synthetic resin Polymers 0.000 description 6
- 239000000057 synthetic resin Substances 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 238000005461 lubrication Methods 0.000 description 5
- 230000005489 elastic deformation Effects 0.000 description 3
- 230000001050 lubricating effect Effects 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000005553 drilling Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000005347 demagnetization Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/10—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis having stationary cylinders
- F04B27/1036—Component parts, details, e.g. sealings, lubrication
- F04B27/109—Lubrication
Definitions
- the present invention relates to a structure of a channel in a variable displacement piston type compressor.
- Japanese Unexamined Patent Publication No. 10-61548 discloses a variable displacement piston type compressor.
- a drive shaft is rotatably supported in a front housing and a cylinder block by a radial bearing.
- Compression reactive force is generated due to the discharge work of a piston.
- the compression reactive force is received by the front housing at its end wall through the piston, a pair of shoes, a swash plate, a lug plate and a thrust bearing.
- the pressure in a crank chamber urges the drive shaft in the direction from the rear side to the front side. Therefore, even when the inclination angle of the swash plate is relatively small, the load acting to the thrust bearing is relatively large.
- the thrust bearing requires lubricating.
- the crank chamber and a suction chamber are connected with each other by an axial passage formed in the drive shaft. Refrigerant in the crank chamber flows into the suction chamber through the axial passage. At this time, lubricant oil that flows with the refrigerant lubricates the thrust bearing.
- the present invention addresses a variable displacement piston type compressor that improves the reliability of a portion requiring lubrication in a crank chamber without increasing the size of the compressor.
- a variable displacement piston type compressor has a housing, a drive shaft, a cam plate and a piston.
- the housing has a cylinder block including a plurality of cylinder bores.
- the housing defines a crank chamber, a suction pressure region and a discharge pressure region.
- the suction pressure region includes a suction chamber.
- the discharge pressure region includes a discharge chamber.
- the drive shaft is rotatably supported by the housing.
- the drive shaft has a first end and a second end. The first end of the drive shaft extends through the housing.
- the cylinder block is placed between the first end and the second end.
- the suction chamber and the discharge chamber are defined near the first end relative to the cylinder block.
- the crank chamber is defined near the second end relative to the cylinder block.
- the cam plate is inclinably supported by the drive shaft in the crank chamber.
- the cam plate is integrally rotated with the drive shaft.
- the piston is accommodated in each cylinder bore. The rotation of the cam plate is converted into the reciprocating movement of the piston in accordance with the inclination angle of the cam plate.
- Refrigerant in the suction chamber is drawn into the cylinder bores due to the suction work of the piston.
- the refrigerant in the cylinder bores is discharged into the discharge chamber due to the discharge work of the piston.
- Refrigerant in the discharge pressure region is supplied into the crank chamber and the refrigerant in the crank chamber is bled into the suction pressure region through a bleed passage for controlling pressure in the crank chamber. Thereby, the inclination angle of the cam plate is controlled.
- the crank chamber and the suction chamber are connected with each other through the bleed passage.
- the bleed passage is formed outside of the drive shaft.
- a variable displacement piston type compressor has a cylinder block, a piston, a cam plate, a crank chamber, a drive shaft, a suction chamber and a discharge chamber.
- the cylinder block includes a plurality of cylinder bores.
- the piston functions so as to compress refrigerant in each cylinder bore.
- the cam plate is movably connected to the piston for reciprocating the piston.
- the crank chamber is defined near one end of the cylinder block.
- the drive shaft has a rotational axis for rotating to drive the cam plate. The drive shaft is urged in a direction of the rotational axis while the piston reciprocates.
- the suction chamber is defined near the opposite end to the crank chamber relative to the cylinder block.
- the refrigerant in the suction chamber is drawn into the cylinder bores due to the suction work of the piston.
- the discharge chamber is defined near the opposite end to the crank chamber relative to the cylinder block.
- the refrigerant in each cylinder bore is discharged to the discharge chamber due to the discharge work of the piston.
- the refrigerant in the discharge chamber is supplied into the crank chamber and the refrigerant in the crank chamber is bled into the suction chamber through a bleed passage for controlling pressure in the crank chamber.
- the bleed passage is formed outside of the drive shaft.
- FIG. 1A is a cross-sectional view of a variable displacement piston type compressor according to a first preferred embodiment of the present invention
- FIG. 1B is a partially enlarged view of the variable displacement piston type compressor of FIG. 1A;
- FIG. 2 is a cross-sectional view of the variable displacement piston type compressor as seen at line I—I in FIG. 1A;
- FIG. 3 is a cross-sectional view of the variable displacement piston type compressor as seen at line 11 —II in FIG. 1A;
- FIG. 4 is a cross-sectional view of the variable displacement piston type compressor as seen at line III—III in FIG. 1A;
- FIG. 5 is a cross-sectional view of the variable displacement piston type compressor as seen at line IV—IV in FIG. 1A;
- FIG. 6 is a partially enlarged view of a variable displacement piston type compressor according to a second preferred embodiment of the present invention.
- FIG. 7 is a partially enlarged view of a variable displacement piston type compressor according to a third preferred embodiment of the present invention.
- FIGS. 1A through 5 A first preferred embodiment according to the present invention in a variable displacement piston type compressor will now be described with reference to FIGS. 1A through 5.
- FIG. 1A the left side and the right side of the drawing respectively correspond to the front side and the rear side of the compressor.
- a front housing 11 and a rear housing 12 constitute a compressor housing 10 .
- An end surface of a circumferential wall 34 of the front housing 11 and an end surface of a circumferential wall 35 of the rear housing 12 are secured to each other through a gasket 36 .
- the front housing 11 and the rear housing 12 are fixed to each other by a plurality of bolts 37 .
- a valve port plate 20 , a suction valve plate 21 , a discharge valve plate 22 and a retainer plate 23 are fitted in the front housing 11 .
- a suction chamber 111 and a discharge chamber 112 are defined between the valve port plate 20 and an end wall 32 of the front housing 11 .
- the suction chamber 111 is separated from the discharge chamber 112 by a separation wall 33 and is surrounded by the discharge chamber 112 .
- the reference numerals in FIG. 4 are applied to substantially the same components in FIG. 1A, and the corresponding description will be provided later with respect to FIG. 1A if it has not yet been provided. If the description has been previously given, it will not be reiterated.
- a cylinder block 19 is fitted in the front housing 11 so as to secure the suction valve plate 21 .
- the end wall 32 of the front housing 11 is screwed by a plurality of screws 38 through the cylinder block 19 .
- the cylinder block 19 is fixed to the front housing 11 .
- the cylinder block 19 has a plurality of cylinder bores 191 . Although only one cylinder bore 191 is shown in FIG. 1A, five cylinder bores are arranged around the drive shaft 13 in the present embodiment as shown in FIGS. 2 and 3.
- the reference numerals in FIGS. 2 and 3 are applied to substantially the same components in FIG. 1A, and the corresponding description will be provided later with respect to FIG. 1A if it has not yet been provided. If the description has been previously given, it will not be reiterated.
- the rear housing 12 and the cylinder block 19 define a crank chamber 121 .
- a drive shaft 13 is rotatably supported by radial bearings 40 and 41 respectively in the rear housing 12 and the cylinder block 19 .
- a pair of accommodation chambers 241 and 242 is defined at the front and rear sides of a flange 192 of the cylinder block 19 .
- the radial bearing 41 is accommodated in the accommodation chamber 241 .
- the drive shaft 13 extends outside of the compressor housing 10 through the shaft hole 24 of the cylinder block 19 and a shaft hole 113 of the front housing 11 .
- a front end of the drive shaft 13 connects with an external drive source such as a vehicle engine through a power transmission mechanism (not shown). Thereby, the drive shaft 13 is driven by the external drive source.
- a shaft seal 39 is placed in the shaft hole 113 so as to prevent the refrigerant in the suction chamber 111 from leaking to the outside of the compressor housing 10 along the circumferential surface 113 of the drive shaft 13 .
- a lug plate 14 is secured to the drive shaft 13 .
- a swash plate 15 is supported by the drive shaft 13 so as to slide along a rotational axis of the drive shaft 13 and is inclinable with respect to the axis of the drive shaft 13 .
- a pair of guide pins 16 is secured to the swash plate 15 .
- the reference numerals in FIG. 5 are applied to substantially the same components in FIG. 1A, and the corresponding description will be provided later with respect to FIG. 1A if it has not yet been provided. If the description has been previously given, it will not be reiterated.
- the guide pins 16 are respectively slidably fitted into a pair of guide holes 141 formed in the lug plate 14 .
- the cooperation of the guide holes 141 and the guide pins 16 allow the swash plate 15 to incline with respect to the axis of the drive shaft 13 and to rotate integrally with the drive shaft 13 .
- the inclination of the swash plate 15 is guided by the slidable movement of the guide pins 16 in the corresponding guide holes 141 under the condition that the swash plate 15 is slidably supported by the drive shaft 13 .
- a piston 17 is accommodated in a corresponding one of the cylinder bores 191 .
- Each of the pistons 17 is connected to the swash plate 15 .
- the rotational movement of the swash plate 15 which integrally rotates with the drive shaft 13 , is converted into the reciprocating movement of the piston 17 through a pair of shoes 18 .
- the piston 17 reciprocates in the corresponding cylinder bores 191 frontward and rearward.
- the suction chamber 111 is included in a suction pressure region. While the piston 17 moves from the left side to the right side in FIG. 1A, the refrigerant in the suction chamber 111 pushes away a corresponding suction valve 211 formed on the suction valve plate 21 from a corresponding suction port 201 formed on the valve port plate 20 . Thereby, the refrigerant in the suction chamber 111 is drawn into the corresponding cylinder bore 191 . While the piston 17 moves from the right side to the left side in FIG. 1A, the refrigerant that has been drawn into the cylinder bore 191 pushes away a corresponding discharge valve 221 formed on the discharge valve plate 22 from a corresponding discharge port 202 formed on the valve port plate 20 .
- the discharge chamber 191 is included in a discharge pressure region.
- the opening degree of the discharge valve 221 is restricted by the abutment of the discharge valve 221 against the retainer 231 , which is formed on the retainer plate 23 .
- valve port plate 20 , the suction valve plate 21 , the discharge valve plate 22 and the retainer plate 23 constitute a valve plate assembly.
- a thrust bearing 42 is interposed between the end wall 122 of the rear housing 12 and the lug plate 14 . Compression reactive force is generated due to the discharge work of the piston 17 and is received by the end wall 122 of the rear housing 12 through the piston 17 , the shoes 18 , the swash plate 15 , the guide pins 16 , the lug plate 14 and the thrust bearing 42 .
- the drive shaft 13 is urged in the direction of a central axis L of the drive shaft 13 while the piston 17 reciprocates.
- a supply passage 30 connects with the discharge chamber 112 and the crank chamber 121 .
- the refrigerant in the discharge chamber 112 is sent to the crank chamber 121 through the supply passage 30 .
- an electromagnetic type displacement control valve 25 is placed in the supply passage 30 .
- the displacement control valve 25 is magnetized and demagnetized by a controller (not shown).
- the controller controls magnetization and demagnetization of the displacement control valve 25 based on a temperature detected by a temperature detector (not shown) that detects temperature in a vehicle compartment and a target temperature set by a temperature setting device (not shown).
- the displacement control valve 25 is closed while electricity is supplied to the displacement control valve 25 .
- the displacement control valve 25 is open while the electricity is stopped being supplied to the displacement control valve 25 .
- the displacement control valve 25 controls the amount of refrigerant that flows from the discharge chamber 112 to the crank chamber 121 .
- a thrust bearing 43 and a shaft seal 44 are placed in the accommodation chamber 242 .
- the pressure in the crank chamber 121 is applied to the rear end surface 132 of the drive shaft 13 .
- the force differential between the sum of the compression reactive forces and the force resulting from the pressure applied to the rear end surface 132 is received by the cylinder block 19 through the drive shaft 13 and the thrust bearing 43 .
- the shaft seal 44 prevents the refrigerant in the suction chamber 111 from leaking to the crank chamber 111 along the circumferential surface 133 of the drive shaft 13 .
- a refrigerant passage 45 is formed in the cylinder block 19 .
- the refrigerant passage 45 has a first end 451 and a second end 452 .
- the first end 451 is opened to a bottom of the crank chamber 121 .
- the second end 452 is opened to a clearance S 1 defined between the inner circumference of the flange 192 and the circumferential surface 133 of the drive shaft 13 .
- the second end 452 is formed more upward than the central axis L of the drive shaft 13 .
- a throttled passage 31 is formed in the refrigerant passage 45 .
- the crank chamber 121 connects with the suction chamber 111 through the refrigerant passage 45 , the clearance S 1 , the gap inside of the radial bearing 41 , the accommodation chamber 241 , and a shaft hole 203 formed in the valve port plate 20 .
- the refrigerant passage 45 , the clearance S 1 , the radial bearing 41 , the accommodation chamber 241 , and the shaft hole 203 constitute a bleed passage 46 .
- the refrigerant in the crank chamber 121 flows into the suction chamber 111 through the bleed passage 46 that connects the crank chamber 121 to the suction chamber 111 .
- the circumferential surface 133 of the drive shaft 13 and the bleed passage 46 in the cylinder block 19 (or the refrigerant passage 45 in the cylinder block 16 ) meet with each other more upward than the central axis L of the drive shaft 13 .
- the inclination angle of the swash plate 15 is varied base on the control of the pressure in the crank chamber 121 .
- the pressure in the crank chamber 121 increases, the inclination angle of the swash plate 15 is decreased relative to the perpendicular plane to the drive shaft 13 .
- the pressure in the crank chamber 121 decreases, the inclination angle of the swash plate 15 is increased relative to the perpendicular plane to the drive shaft 13 .
- the refrigerant in the discharge chamber 112 is supplied to the crank chamber 121 , the pressure in the crank chamber 121 is increased.
- the pressure in the crank chamber 121 is decreased. That is, the inclination angle of the swash plate 15 is controlled by the displacement control valve 25 .
- the maximum inclination angle of the swash plate 15 is restricted by the abutment of the swash plate 15 against the lug plate 14 .
- the minimum inclination angle of the swash plate 15 is restricted by the abutment of the swash plate 15 against the circular clip 47 .
- the discharge chamber 112 and the suction chamber 111 connect with each other through an external refrigerant circuit 26 .
- the refrigerant that has been flowed into the external refrigerant circuit 26 from the discharge chamber 112 is returned to the suction chamber 111 in the compressor through a condenser 27 , an expansion valve 28 and an evaporator 29 .
- the diameter of the drive shaft 13 can be reduced than that of the drive shaft 13 of which a bleed passage 46 is formed inside.
- the reduction of the diameter of the drive shaft 13 enables the compressor to be compact. Therefore, the constitution that the bleed passage 46 is formed outside of the drive shaft 13 is effective to prevent the compressor from becoming large.
- the compression reactive force is generated due to the discharge work of the piston 17 in the direction from the front end of the drive shaft 13 to the rear end of the drive shaft 13 .
- the compression reactive force is relatively small.
- the pressure in the crank chamber 121 urges the drive shaft 13 in the direction from the rear end of the drive shaft 13 to the front end of the drive shaft 13 . Therefore, when the inclination angle of the swash plate 15 is relatively small, the load that is applied to the thrust bearing 42 for receiving the compression reactive force is substantially zero or relatively extremely small.
- the constitution that the suction chamber 111 and the discharge chamber 112 are separated from the crank chamber 121 through the cylinder block 19 in the direction from the front end of the drive shaft 13 to the rear end of the drive shaft 13 is effective to improve the reliability of the thrust bearing 42 , which is a portion requiring lubrication in the crank chamber 121 .
- a part of the bleed passage 46 is formed in the shaft hole 24 of the cylinder block 19 .
- the gap can function as a part of the bleed passage 46 .
- the diameter of the shaft hole 24 is formed to be larger than that of the drive shaft 13 . The constitution having such a relation between the diameters is easily obtained. Accordingly, the shaft hole 24 of the cylinder block 19 is suitable for forming at least a part of the bleed passage 46 .
- the radial bearing 41 in the bleed passage 46 is lubricated by the lubricant oil that flows with the refrigerant passing through the bleed passage 46 . Therefore, the shaft hole 24 provided with the radial bearing 41 is suitable for forming the bleed passage 46 .
- the constitution that the lubricant oil Y that has accumulated at the bottom of the crank chamber 121 is sent to the suction chamber 111 is effective to raise a lubricating efficiency of portions requiring lubrication such as the radial bearing 41 and the shaft seal 39 other than the portion requiring lubrication in the crank chamber 121 .
- the second end 452 of the refrigerant passage 45 is opened to the clearance S 1 .
- the second end 452 is at a higher position than the central axis L of the drive shaft 13 . Therefore, the lubricant oil can accumulate even in the clearance S 1 and the accommodation chamber 241 . Thereby, the lubricating efficiency of the radial bearing 41 is raised.
- a second preferred embodiment according to the present invention in a variable displacement piston type compressor will now be described with reference to FIG. 6.
- the same reference numerals of the first preferred embodiment are applied to substantially the same elements in the second preferred embodiment.
- a shaft seal 44 A is placed in the accommodation chamber 241 .
- the shaft seal 44 A prevents the refrigerant in the accommodation chamber 241 from leaking to the suction chamber 111 along the circumferential surface 133 of the drive shaft 13 .
- the accommodation chamber 241 and the suction chamber 111 are connected by a refrigerant passage 48 formed in the cylinder block 19 and a throttled passage 49 formed through the valve port plate 20 .
- a first end 481 of the refrigerant passage 48 is opened relatively upward in the accommodation chamber 241 .
- a clearance S 2 is defined between an inner circumferential surface of a race 431 of the thrust bearing 43 and the circumferential surface 133 of the drive shaft 13 .
- the refrigerant in the crank chamber 121 flows to the suction chamber 111 through a bleed passage 50 constituted of a gap between the race 431 and a race 432 of the thrust bearing 43 , the clearance S 2 , the clearance S 1 , a gap in the radial bearing 41 , the accommodation chamber 241 , the refrigerant passage 48 and the throttled passage 49 .
- the throttled passage 49 requires a relatively small diameter so as to properly adjust the pressure in the crank chamber 121 . It is difficult to form a passage having a relatively small diameter and a relatively large length by drilling. However, since the thickness of the valve port plate 20 is not relatively large, the length of the throttled passage 49 becomes relatively small. Therefore, the valve port plate 20 is suitable for forming the throttled passage 49 having a relatively small diameter.
- a third preferred embodiment according to the present invention in a variable displacement piston type compressor will now be described with reference to FIG. 7.
- the same reference numerals of the first preferred embodiment are applied to substantially the same elements in the third preferred embodiment.
- An annular blocking body 51 made of synthetic resin is placed in the accommodation chamber 241 .
- the blocking body 51 is made of polytetrafluoroethylene.
- the blocking body 51 is slidable respective to the circumferential surface in the accommodation chamber 241 , the circumferential surface 133 of the drive shaft 13 and the suction valve plate 21 .
- Grooves 52 and 521 are formed respectively on the outer circumferential surface 512 and the end surface 513 of the blocking body 51 .
- the refrigerant in the crank chamber 121 flows to the suction chamber 111 through the gap in the thrust bearing 43 , the clearances S 2 and S 1 , the gap in the thrust bearing 41 , the accommodation chamber 241 , the grooves 52 and 521 , and the shaft hole 203 . That is, the pressure in the crank chamber 121 is adjusted by the outflow of the refrigerant in the crank chamber 121 (or the release of the pressure in the crank chamber 121 ) through the grooves 52 and 521 of the blocking body 51 that are throttling means.
- the grooves 52 and 521 of the blocking body 51 function as a throttle so as to separate the pressure in the suction chamber 111 from the pressure in the crank chamber 121 .
- the blocking body 51 is placed for leaking the refrigerant properly from the crank chamber 121 to the suction chamber 111 .
- the refrigerant in the crank chamber 121 leaks through a gap between the outer circumferential surface 512 of the blocking body 51 and the circumferential surface of the accommodation chamber 241 and a gap between the inner circumferential surface 511 of the blocking body 51 and the circumferential surface 133 of the drive shaft 13 . Therefore, the function for preventing the refrigerant from leaking through the gaps does not require its accuracy.
- the elastic deformation of the blocking body 51 made of synthetic resin enables the blocking body 51 to fit into the accommodation chamber 241 . Also, even when the inside diameter of the blocking body 51 is slightly smaller than the diameter of the drive shaft 13 , the elastic deformation of the blocking body 51 made of synthetic resin enables the blocking body 51 to fit around the drive shaft 13 .
- the blocking body 51 made of synthetic resin permits low accuracy in size.
- Such a blocking body is manufactured at low cost and is easily manufactured by molding.
- the grooves 52 and 521 are formed respectively on the outer circumferential surface 512 and the end surface 513 of the blocking body 51 .
- the outer circumferential surface 512 and the end surface 513 of the blocking body 51 are easy to form a groove. Therefore, the surface of the blocking body 51 is suitable for forming the grooves 52 and 521 .
- a bleed passage that linearly extends through the cylinder block 19 , the suction valve plate 21 , the valve port plate 20 and the discharge valve plate 22 may connect with the crank chamber 121 and the suction chamber 111 .
- the refrigerant passage 48 and the throttled passage 49 may be omitted.
- a throttled passage may be formed in the shaft seal 44 A.
- a blocking body 51 made of rubber may be employed.
- a nitrile-butadiene rubber may be employed.
- the nitrile-butadiene rubber that is excellent in a resistance to deterioration relative to refrigerant and lubricant oil is suitable for a material of the blocking body 51 .
- the blocking body 51 made of rubber is formed by molding, the elastic deformation of rubber allows rubber to be lower accuracy in size than synthetic resin. Therefore, the blocking body 51 made of rubber is manufactured more easily than a blocking body made of synthetic resin.
Abstract
A variable displacement piston type compressor has a housing, a drive shaft, a cam plate and a piston. The drive shaft is rotatably supported by the housing. The drive shaft has a first end and a second end. The first end of the drive shaft extends through the housing. The cylinder block is placed between the first end and the second end. The suction chamber and the discharge chamber are defined near the first end relative to the cylinder block. The crank chamber is defined near the second end relative to the cylinder block. The refrigerant in the crank chamber is bled into the suction pressure region through a bleed passage. Thereby, the inclination angle of the cam plate is controlled. The crank chamber and the suction chamber are connected with each other through the bleed passage. The bleed passage is formed outside of the drive shaft.
Description
- The present invention relates to a structure of a channel in a variable displacement piston type compressor.
- Japanese Unexamined Patent Publication No. 10-61548 discloses a variable displacement piston type compressor. In the constitution, a drive shaft is rotatably supported in a front housing and a cylinder block by a radial bearing. Compression reactive force is generated due to the discharge work of a piston. The compression reactive force is received by the front housing at its end wall through the piston, a pair of shoes, a swash plate, a lug plate and a thrust bearing. When the inclination angle of the swash plate is relatively small, the compression reactive force is relatively small. However, the pressure in a crank chamber urges the drive shaft in the direction from the rear side to the front side. Therefore, even when the inclination angle of the swash plate is relatively small, the load acting to the thrust bearing is relatively large.
- To improve the durability of the thrust bearing, the thrust bearing requires lubricating. In the prior art, the crank chamber and a suction chamber are connected with each other by an axial passage formed in the drive shaft. Refrigerant in the crank chamber flows into the suction chamber through the axial passage. At this time, lubricant oil that flows with the refrigerant lubricates the thrust bearing.
- In the above constitution that an axial passage is formed in the drive shaft, however, the diameter of the drive shaft is increased. Thereby, the size of the compressor is increased. In addition, a cost for machining the drive shaft is increased. Thereby, a cost for manufacturing the compressor is increased.
- The present invention addresses a variable displacement piston type compressor that improves the reliability of a portion requiring lubrication in a crank chamber without increasing the size of the compressor.
- According to the present invention, the present invention has following features. A variable displacement piston type compressor has a housing, a drive shaft, a cam plate and a piston. The housing has a cylinder block including a plurality of cylinder bores. The housing defines a crank chamber, a suction pressure region and a discharge pressure region. The suction pressure region includes a suction chamber. The discharge pressure region includes a discharge chamber. The drive shaft is rotatably supported by the housing. The drive shaft has a first end and a second end. The first end of the drive shaft extends through the housing. The cylinder block is placed between the first end and the second end. The suction chamber and the discharge chamber are defined near the first end relative to the cylinder block. The crank chamber is defined near the second end relative to the cylinder block. The cam plate is inclinably supported by the drive shaft in the crank chamber. The cam plate is integrally rotated with the drive shaft. The piston is accommodated in each cylinder bore. The rotation of the cam plate is converted into the reciprocating movement of the piston in accordance with the inclination angle of the cam plate. Refrigerant in the suction chamber is drawn into the cylinder bores due to the suction work of the piston. The refrigerant in the cylinder bores is discharged into the discharge chamber due to the discharge work of the piston. Refrigerant in the discharge pressure region is supplied into the crank chamber and the refrigerant in the crank chamber is bled into the suction pressure region through a bleed passage for controlling pressure in the crank chamber. Thereby, the inclination angle of the cam plate is controlled. The crank chamber and the suction chamber are connected with each other through the bleed passage. The bleed passage is formed outside of the drive shaft.
- Furthermore, the present invention has following features. A variable displacement piston type compressor has a cylinder block, a piston, a cam plate, a crank chamber, a drive shaft, a suction chamber and a discharge chamber. The cylinder block includes a plurality of cylinder bores. The piston functions so as to compress refrigerant in each cylinder bore. The cam plate is movably connected to the piston for reciprocating the piston. The crank chamber is defined near one end of the cylinder block. The drive shaft has a rotational axis for rotating to drive the cam plate. The drive shaft is urged in a direction of the rotational axis while the piston reciprocates. The suction chamber is defined near the opposite end to the crank chamber relative to the cylinder block. The refrigerant in the suction chamber is drawn into the cylinder bores due to the suction work of the piston. The discharge chamber is defined near the opposite end to the crank chamber relative to the cylinder block. The refrigerant in each cylinder bore is discharged to the discharge chamber due to the discharge work of the piston. The refrigerant in the discharge chamber is supplied into the crank chamber and the refrigerant in the crank chamber is bled into the suction chamber through a bleed passage for controlling pressure in the crank chamber. The bleed passage is formed outside of the drive shaft.
- The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
- FIG. 1A is a cross-sectional view of a variable displacement piston type compressor according to a first preferred embodiment of the present invention;
- FIG. 1B is a partially enlarged view of the variable displacement piston type compressor of FIG. 1A;
- FIG. 2 is a cross-sectional view of the variable displacement piston type compressor as seen at line I—I in FIG. 1A;
- FIG. 3 is a cross-sectional view of the variable displacement piston type compressor as seen at
line 11 —II in FIG. 1A; - FIG. 4 is a cross-sectional view of the variable displacement piston type compressor as seen at line III—III in FIG. 1A;
- FIG. 5 is a cross-sectional view of the variable displacement piston type compressor as seen at line IV—IV in FIG. 1A;
- FIG. 6 is a partially enlarged view of a variable displacement piston type compressor according to a second preferred embodiment of the present invention; and
- FIG. 7 is a partially enlarged view of a variable displacement piston type compressor according to a third preferred embodiment of the present invention.
- A first preferred embodiment according to the present invention in a variable displacement piston type compressor will now be described with reference to FIGS. 1A through 5. Referring particularly to FIG. 1A, the left side and the right side of the drawing respectively correspond to the front side and the rear side of the compressor.
- As shown in FIG. 1A, a
front housing 11 and arear housing 12 constitute acompressor housing 10. An end surface of acircumferential wall 34 of thefront housing 11 and an end surface of acircumferential wall 35 of therear housing 12 are secured to each other through agasket 36. Thefront housing 11 and therear housing 12 are fixed to each other by a plurality ofbolts 37. - Still referring to FIG. 1A, a
valve port plate 20, asuction valve plate 21, adischarge valve plate 22 and aretainer plate 23 are fitted in thefront housing 11. Asuction chamber 111 and adischarge chamber 112 are defined between thevalve port plate 20 and anend wall 32 of thefront housing 11. As shown in FIG. 4, thesuction chamber 111 is separated from thedischarge chamber 112 by aseparation wall 33 and is surrounded by thedischarge chamber 112. The reference numerals in FIG. 4 are applied to substantially the same components in FIG. 1A, and the corresponding description will be provided later with respect to FIG. 1A if it has not yet been provided. If the description has been previously given, it will not be reiterated. - Referring back to FIG. 1A, a
cylinder block 19 is fitted in thefront housing 11 so as to secure thesuction valve plate 21. Theend wall 32 of thefront housing 11 is screwed by a plurality ofscrews 38 through thecylinder block 19. Thereby, thecylinder block 19 is fixed to thefront housing 11. Thecylinder block 19 has a plurality of cylinder bores 191. Although only onecylinder bore 191 is shown in FIG. 1A, five cylinder bores are arranged around thedrive shaft 13 in the present embodiment as shown in FIGS. 2 and 3. The reference numerals in FIGS. 2 and 3 are applied to substantially the same components in FIG. 1A, and the corresponding description will be provided later with respect to FIG. 1A if it has not yet been provided. If the description has been previously given, it will not be reiterated. - Referring back to FIG. 1A, the
rear housing 12 and thecylinder block 19 define a crankchamber 121. Adrive shaft 13 is rotatably supported byradial bearings rear housing 12 and thecylinder block 19. In ashaft hole 24 of the cylinder block 19 a pair ofaccommodation chambers flange 192 of thecylinder block 19. Theradial bearing 41 is accommodated in theaccommodation chamber 241. Thedrive shaft 13 extends outside of thecompressor housing 10 through theshaft hole 24 of thecylinder block 19 and ashaft hole 113 of thefront housing 11. A front end of thedrive shaft 13 connects with an external drive source such as a vehicle engine through a power transmission mechanism (not shown). Thereby, thedrive shaft 13 is driven by the external drive source. Ashaft seal 39 is placed in theshaft hole 113 so as to prevent the refrigerant in thesuction chamber 111 from leaking to the outside of thecompressor housing 10 along thecircumferential surface 113 of thedrive shaft 13. - Still referring to FIG. 1A, a
lug plate 14 is secured to thedrive shaft 13. Aswash plate 15 is supported by thedrive shaft 13 so as to slide along a rotational axis of thedrive shaft 13 and is inclinable with respect to the axis of thedrive shaft 13. As shown in FIG. 5, a pair of guide pins 16 is secured to theswash plate 15. The reference numerals in FIG. 5 are applied to substantially the same components in FIG. 1A, and the corresponding description will be provided later with respect to FIG. 1A if it has not yet been provided. If the description has been previously given, it will not be reiterated. The guide pins 16 are respectively slidably fitted into a pair of guide holes 141 formed in thelug plate 14. The cooperation of the guide holes 141 and the guide pins 16 allow theswash plate 15 to incline with respect to the axis of thedrive shaft 13 and to rotate integrally with thedrive shaft 13. The inclination of theswash plate 15 is guided by the slidable movement of the guide pins 16 in the corresponding guide holes 141 under the condition that theswash plate 15 is slidably supported by thedrive shaft 13. - Referring back to FIG. 1A, a
piston 17 is accommodated in a corresponding one of the cylinder bores 191. Each of thepistons 17 is connected to theswash plate 15. The rotational movement of theswash plate 15, which integrally rotates with thedrive shaft 13, is converted into the reciprocating movement of thepiston 17 through a pair ofshoes 18. Thereby, thepiston 17 reciprocates in the corresponding cylinder bores 191 frontward and rearward. - The
suction chamber 111 is included in a suction pressure region. While thepiston 17 moves from the left side to the right side in FIG. 1A, the refrigerant in thesuction chamber 111 pushes away acorresponding suction valve 211 formed on thesuction valve plate 21 from acorresponding suction port 201 formed on thevalve port plate 20. Thereby, the refrigerant in thesuction chamber 111 is drawn into the corresponding cylinder bore 191. While thepiston 17 moves from the right side to the left side in FIG. 1A, the refrigerant that has been drawn into the cylinder bore 191 pushes away acorresponding discharge valve 221 formed on thedischarge valve plate 22 from acorresponding discharge port 202 formed on thevalve port plate 20. Thereby, the refrigerant in the cylinder bore 191 is discharged into thecorresponding discharge chamber 112. Thedischarge chamber 191 is included in a discharge pressure region. The opening degree of thedischarge valve 221 is restricted by the abutment of thedischarge valve 221 against theretainer 231, which is formed on theretainer plate 23. - In the present embodiment, the
valve port plate 20, thesuction valve plate 21, thedischarge valve plate 22 and theretainer plate 23 constitute a valve plate assembly. Athrust bearing 42 is interposed between theend wall 122 of therear housing 12 and thelug plate 14. Compression reactive force is generated due to the discharge work of thepiston 17 and is received by theend wall 122 of therear housing 12 through thepiston 17, theshoes 18, theswash plate 15, the guide pins 16, thelug plate 14 and thethrust bearing 42. At this time, thedrive shaft 13 is urged in the direction of a central axis L of thedrive shaft 13 while thepiston 17 reciprocates. - A
supply passage 30 connects with thedischarge chamber 112 and thecrank chamber 121. The refrigerant in thedischarge chamber 112 is sent to the crankchamber 121 through thesupply passage 30. In thesupply passage 30, an electromagnetic typedisplacement control valve 25 is placed. Thedisplacement control valve 25 is magnetized and demagnetized by a controller (not shown). The controller controls magnetization and demagnetization of thedisplacement control valve 25 based on a temperature detected by a temperature detector (not shown) that detects temperature in a vehicle compartment and a target temperature set by a temperature setting device (not shown). Thedisplacement control valve 25 is closed while electricity is supplied to thedisplacement control valve 25. Thedisplacement control valve 25 is open while the electricity is stopped being supplied to thedisplacement control valve 25. That is, on one hand the refrigerant in thedischarge chamber 112 is sent to the crankchamber 121 while thedisplacement control valve 25 is demagnetized, and on the other hand the refrigerant in thedischarge chamber 112 is not sent to the crankchamber 121 while thedisplacement control valve 25 is magnetized. Thus, thedisplacement control valve 25 controls the amount of refrigerant that flows from thedischarge chamber 112 to the crankchamber 121. - In the
accommodation chamber 242, athrust bearing 43 and ashaft seal 44 are placed. The pressure in thecrank chamber 121 is applied to therear end surface 132 of thedrive shaft 13. In the case that the sum of the compression reactive forces acting on thepistons 17 in the cylinder bores 191 is smaller than the force resulting from the pressure applied to therear end surface 132, the force differential between the sum of the compression reactive forces and the force resulting from the pressure applied to therear end surface 132 is received by thecylinder block 19 through thedrive shaft 13 and thethrust bearing 43. Theshaft seal 44 prevents the refrigerant in thesuction chamber 111 from leaking to the crankchamber 111 along thecircumferential surface 133 of thedrive shaft 13. - In the
cylinder block 19, arefrigerant passage 45 is formed. Therefrigerant passage 45 has afirst end 451 and asecond end 452. Thefirst end 451 is opened to a bottom of thecrank chamber 121. As shown in FIGS. 2 and 3, thesecond end 452 is opened to a clearance S1 defined between the inner circumference of theflange 192 and thecircumferential surface 133 of thedrive shaft 13. Thesecond end 452 is formed more upward than the central axis L of thedrive shaft 13. A throttledpassage 31 is formed in therefrigerant passage 45. - As shown in FIGS. 1A and 1B, the
crank chamber 121 connects with thesuction chamber 111 through therefrigerant passage 45, the clearance S1, the gap inside of theradial bearing 41, theaccommodation chamber 241, and ashaft hole 203 formed in thevalve port plate 20. Therefrigerant passage 45, the clearance S1, theradial bearing 41, theaccommodation chamber 241, and theshaft hole 203 constitute ableed passage 46. The refrigerant in thecrank chamber 121 flows into thesuction chamber 111 through thebleed passage 46 that connects thecrank chamber 121 to thesuction chamber 111. Thecircumferential surface 133 of thedrive shaft 13 and thebleed passage 46 in the cylinder block 19 (or therefrigerant passage 45 in the cylinder block 16) meet with each other more upward than the central axis L of thedrive shaft 13. - The inclination angle of the
swash plate 15 is varied base on the control of the pressure in thecrank chamber 121. As the pressure in thecrank chamber 121 increases, the inclination angle of theswash plate 15 is decreased relative to the perpendicular plane to thedrive shaft 13. In contrast, as the pressure in thecrank chamber 121 decreases, the inclination angle of theswash plate 15 is increased relative to the perpendicular plane to thedrive shaft 13. As the refrigerant in thedischarge chamber 112 is supplied to the crankchamber 121, the pressure in thecrank chamber 121 is increased. When the supply of the refrigerant from thedischarge chamber 112 to the crankchamber 121 stops, the pressure in thecrank chamber 121 is decreased. That is, the inclination angle of theswash plate 15 is controlled by thedisplacement control valve 25. - The maximum inclination angle of the
swash plate 15 is restricted by the abutment of theswash plate 15 against thelug plate 14. The minimum inclination angle of theswash plate 15 is restricted by the abutment of theswash plate 15 against the circular clip 47. - The
discharge chamber 112 and thesuction chamber 111 connect with each other through an externalrefrigerant circuit 26. The refrigerant that has been flowed into the externalrefrigerant circuit 26 from thedischarge chamber 112 is returned to thesuction chamber 111 in the compressor through acondenser 27, anexpansion valve 28 and anevaporator 29. - In the first preferred embodiment of the present invention, the following advantageous effects are obtained.
- (1-1) When the opening degree of the
displacement control valve 25 is not zero degree, a part of the refrigerant in thedischarge chamber 112 flows into thecrank chamber 121 through thesupply passage 30. In addition, the lubricant oil that flows with the refrigerant flows from thedischarge chamber 112 into thecrank chamber 121. The refrigerant in thecrank chamber 121 flows into thesuction chamber 111 through thebleed passage 46. In addition, the lubricant oil that flows with the refrigerant flows from thecrank chamber 121 into thesuction chamber 111. Thebleed passage 46, which is required to control displacement and to lubricate a portion requiring lubrication in thecrank chamber 121, is formed outside of thedrive shaft 13. In the constitution that thebleed passage 46 is formed outside of thedrive shaft 13, the diameter of thedrive shaft 13 can be reduced than that of thedrive shaft 13 of which ableed passage 46 is formed inside. The reduction of the diameter of thedrive shaft 13 enables the compressor to be compact. Therefore, the constitution that thebleed passage 46 is formed outside of thedrive shaft 13 is effective to prevent the compressor from becoming large. - (1-2) The compression reactive force is generated due to the discharge work of the
piston 17 in the direction from the front end of thedrive shaft 13 to the rear end of thedrive shaft 13. When the inclination angle of theswash plate 15 is relatively small, the compression reactive force is relatively small. The pressure in thecrank chamber 121 urges thedrive shaft 13 in the direction from the rear end of thedrive shaft 13 to the front end of thedrive shaft 13. Therefore, when the inclination angle of theswash plate 15 is relatively small, the load that is applied to thethrust bearing 42 for receiving the compression reactive force is substantially zero or relatively extremely small. That is, the constitution that thesuction chamber 111 and thedischarge chamber 112 are separated from thecrank chamber 121 through thecylinder block 19 in the direction from the front end of thedrive shaft 13 to the rear end of thedrive shaft 13 is effective to improve the reliability of thethrust bearing 42, which is a portion requiring lubrication in thecrank chamber 121. - (1-3) A part of the
bleed passage 46 is formed in theshaft hole 24 of thecylinder block 19. When a gap exists between the circumferential surface of theshaft hole 24 and thecircumferential surface 133 of thedrive shaft 13, the gap can function as a part of thebleed passage 46. To define the gap between the circumferential surface of theshaft hole 24 and thecircumferential surface 133 of thedrive shaft 13, the diameter of theshaft hole 24 is formed to be larger than that of thedrive shaft 13. The constitution having such a relation between the diameters is easily obtained. Accordingly, theshaft hole 24 of thecylinder block 19 is suitable for forming at least a part of thebleed passage 46. - (1-4) The
radial bearing 41 in thebleed passage 46 is lubricated by the lubricant oil that flows with the refrigerant passing through thebleed passage 46. Therefore, theshaft hole 24 provided with theradial bearing 41 is suitable for forming thebleed passage 46. - (1-5) The
first end 451 of therefrigerant passage 45 that is a first end of thebleed passage 46 is opened to the bottom of thecrank chamber 121. As shown in FIG. 1A, lubricant oil Y accumulates at the bottom of thecrank chamber 121. The lubricant oil Y is sent to thebleed passage 46 since the refrigerant in thecrank chamber 121 flows to thesuction chamber 111. The constitution that the lubricant oil Y that has accumulated at the bottom of thecrank chamber 121 is sent to thesuction chamber 111 is effective to raise a lubricating efficiency of portions requiring lubrication such as theradial bearing 41 and theshaft seal 39 other than the portion requiring lubrication in thecrank chamber 121. - (1-6) The
second end 452 of therefrigerant passage 45 is opened to the clearance S1. Thesecond end 452 is at a higher position than the central axis L of thedrive shaft 13. Therefore, the lubricant oil can accumulate even in the clearance S1 and theaccommodation chamber 241. Thereby, the lubricating efficiency of theradial bearing 41 is raised. - A second preferred embodiment according to the present invention in a variable displacement piston type compressor will now be described with reference to FIG. 6. The same reference numerals of the first preferred embodiment are applied to substantially the same elements in the second preferred embodiment.
- Referring to FIG. 6, a
shaft seal 44A is placed in theaccommodation chamber 241. Theshaft seal 44A prevents the refrigerant in theaccommodation chamber 241 from leaking to thesuction chamber 111 along thecircumferential surface 133 of thedrive shaft 13. Theaccommodation chamber 241 and thesuction chamber 111 are connected by arefrigerant passage 48 formed in thecylinder block 19 and a throttledpassage 49 formed through thevalve port plate 20. Afirst end 481 of therefrigerant passage 48 is opened relatively upward in theaccommodation chamber 241. - A clearance S2 is defined between an inner circumferential surface of a
race 431 of thethrust bearing 43 and thecircumferential surface 133 of thedrive shaft 13. The refrigerant in thecrank chamber 121 flows to thesuction chamber 111 through ableed passage 50 constituted of a gap between therace 431 and arace 432 of thethrust bearing 43, the clearance S2, the clearance S1, a gap in theradial bearing 41, theaccommodation chamber 241, therefrigerant passage 48 and the throttledpassage 49. - In the second preferred embodiment, the above-described effects (1-1) through (1-4) of the first preferred embodiment are substantially obtained. In addition, the following effects are obtained.
- (2-1) The throttled
passage 49 requires a relatively small diameter so as to properly adjust the pressure in thecrank chamber 121. It is difficult to form a passage having a relatively small diameter and a relatively large length by drilling. However, since the thickness of thevalve port plate 20 is not relatively large, the length of the throttledpassage 49 becomes relatively small. Therefore, thevalve port plate 20 is suitable for forming the throttledpassage 49 having a relatively small diameter. - (2-2) Since the
cylinder block 19 does not require a throttled passage having a relatively small diameter, therefrigerant passage 48 having a proper diameter is easily formed by drilling. - A third preferred embodiment according to the present invention in a variable displacement piston type compressor will now be described with reference to FIG. 7. The same reference numerals of the first preferred embodiment are applied to substantially the same elements in the third preferred embodiment.
- An
annular blocking body 51 made of synthetic resin is placed in theaccommodation chamber 241. For example, the blockingbody 51 is made of polytetrafluoroethylene. The blockingbody 51 is slidable respective to the circumferential surface in theaccommodation chamber 241, thecircumferential surface 133 of thedrive shaft 13 and thesuction valve plate 21.Grooves circumferential surface 512 and theend surface 513 of the blockingbody 51. The refrigerant in thecrank chamber 121 flows to thesuction chamber 111 through the gap in thethrust bearing 43, the clearances S2 and S1, the gap in thethrust bearing 41, theaccommodation chamber 241, thegrooves shaft hole 203. That is, the pressure in thecrank chamber 121 is adjusted by the outflow of the refrigerant in the crank chamber 121 (or the release of the pressure in the crank chamber 121) through thegrooves body 51 that are throttling means. Thegrooves body 51 function as a throttle so as to separate the pressure in thesuction chamber 111 from the pressure in thecrank chamber 121. - In the third preferred embodiment, the above-described effects (1-1) through (1-4) of the first preferred embodiment are substantially obtained. In addition, the following effects are obtained.
- (3-1) In a sense, the blocking
body 51 is placed for leaking the refrigerant properly from thecrank chamber 121 to thesuction chamber 111. The refrigerant in thecrank chamber 121 leaks through a gap between the outercircumferential surface 512 of the blockingbody 51 and the circumferential surface of theaccommodation chamber 241 and a gap between the innercircumferential surface 511 of the blockingbody 51 and thecircumferential surface 133 of thedrive shaft 13. Therefore, the function for preventing the refrigerant from leaking through the gaps does not require its accuracy. Accordingly, it is not required that the outercircumferential surface 512 of the blockingbody 51 is completely close to the circumferential surface of theaccommodation chamber 241 and that the innercircumferential surface 511 of the blockingbody 51 is completely close to thecircumferential surface 133 of thedrive shaft 13. - Even when the outside diameter of the blocking
body 51 is slightly larger than the diameter of theaccommodation chamber 241, the elastic deformation of the blockingbody 51 made of synthetic resin enables the blockingbody 51 to fit into theaccommodation chamber 241. Also, even when the inside diameter of the blockingbody 51 is slightly smaller than the diameter of thedrive shaft 13, the elastic deformation of the blockingbody 51 made of synthetic resin enables the blockingbody 51 to fit around thedrive shaft 13. - In other words, the blocking
body 51 made of synthetic resin permits low accuracy in size. Such a blocking body is manufactured at low cost and is easily manufactured by molding. - (3-2) Although the cross-sectional area for passing the
grooves grooves - (3-3) The
grooves circumferential surface 512 and theend surface 513 of the blockingbody 51. The outercircumferential surface 512 and theend surface 513 of the blockingbody 51 are easy to form a groove. Therefore, the surface of the blockingbody 51 is suitable for forming thegrooves - (3-4) When the outside diameter of the blocking
body 51 is much smaller than the diameter of theaccommodation chamber 241, the sum of the cross-sectional area for passing a clearance between the circumferential surface of theaccommodation chamber 241 and the outercircumferential surface 512 of the blockingbody 51 and the cross-sectional area for passing thegroove 52 is much larger than the desired value of the cross-sectional area of the throttle. However, theend surface 513 of the blockingbody 51 is closed to thesuction valve plate 21 due to the pressure differential between thecrank chamber 121 and thesuction chamber 111. In addition, a part of thegroove 521 formed on theend surface 513 faces to thesuction valve plate 21. Therefore, the cross-sectional area for passing a clearance between theend surface 513 and thesuction valve plate 21 is prescribed to be a desired value of the cross-sectional area for passing thegroove 521. Thereby, a satisfactory throttle is ensured. - (3-5) The polytetrafluoroethylene that is excellent in a sliding performance is suitable for a material of the blocking
body 51. - In the present invention, the following embodiments are also practiced.
- Firstly, a bleed passage that linearly extends through the
cylinder block 19, thesuction valve plate 21, thevalve port plate 20 and thedischarge valve plate 22 may connect with thecrank chamber 121 and thesuction chamber 111. - Secondly, in the second preferred embodiment, the
refrigerant passage 48 and the throttledpassage 49 may be omitted. In place of therefrigerant passage 48 and the throttledpassage 49, a throttled passage may be formed in theshaft seal 44A. - Thirdly, in the third preferred embodiment, a blocking
body 51 made of rubber may be employed. For example, a nitrile-butadiene rubber may be employed. - The nitrile-butadiene rubber that is excellent in a resistance to deterioration relative to refrigerant and lubricant oil is suitable for a material of the blocking
body 51. While the blockingbody 51 made of rubber is formed by molding, the elastic deformation of rubber allows rubber to be lower accuracy in size than synthetic resin. Therefore, the blockingbody 51 made of rubber is manufactured more easily than a blocking body made of synthetic resin. - The present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein but may be modified within the scope of the appended claims.
Claims (18)
1. A variable displacement piston type compressor comprising:
a housing having a cylinder block including a plurality of cylinder bores, the housing defining a crank chamber, a suction pressure region and a discharge pressure region, the suction pressure region including a suction chamber, the discharge pressure region including a discharge chamber;
a drive shaft rotatably supported by the housing, the drive shaft having a first end and a second end, the first end of the drive shaft extending through the housing, the cylinder block being placed between the first end and the second end, the suction chamber and the discharge chamber being defined near the first end relative to the cylinder block, the crank chamber being defined near the second end relative to the cylinder block;
a cam plate inclinably supported by the drive shaft in the crank chamber, the cam plate being integrally rotated with the drive shaft;
a piston accommodated in each cylinder bore, the rotation of the cam plate being converted into the reciprocating movement of the piston in accordance with the inclination angle of the cam plate, refrigerant in the suction chamber being drawn into the cylinder bores due to the suction work of the piston, the refrigerant in the cylinder bores being discharged into the discharge chamber due to the discharge work of the piston, refrigerant in the discharge pressure region being supplied into the crank chamber and the refrigerant in the crank chamber being bled into the suction pressure region through a bleed passage for controlling pressure in the crank chamber, thereby the inclination angle of the cam plate being controlled, the crank chamber and the suction chamber being connected with each other through the bleed passage, the bleed passage being formed outside of the drive shaft.
2. The variable displacement piston type compressor according to claim 1 , wherein at least a part of the bleed passage is formed in a shaft hole of the cylinder block through which the drive shaft extends.
3. The variable displacement piston type compressor according to claim 2 , wherein the drive shaft is rotatably supported by a radial bearing in the cylinder block, the radial bearing being placed in the bleed passage.
4. The variable displacement piston type compressor according to claim 1 , wherein the discharge chamber and the suction chamber are separated from the cylinder bores by a valve plate assembly, a part of the bleed passage extends through the cylinder block and the valve plate assembly, and a part of the bleed passage in the valve plate assembly is a throttled passage.
5. The variable displacement piston type compressor according to claim 1 , wherein the upstream end of the bleed passage is opened to the bottom of the crank chamber.
6. The variable displacement piston type compressor according to claim 5 , wherein the bleed passage passes through the cylinder block and then reaches the circumferential surface of the drive shaft, and the circumferential surface of the drive shaft and the bleed passage in the cylinder block meet more upward in a vertical direction than the central axis of the drive shaft.
7. The variable displacement piston type compressor according to claim 1 , further comprising a throttling means having a blocking member in the bleed passage and a throttled passage formed on the blocking member, the blocking member being made of resin or rubber.
8. The variable displacement piston type compressor according to claim 7 , wherein the blocking member is made of polytetrafluoroethylene.
9. The variable displacement piston type compressor according to claim 7 , wherein the blocking member is made of nitrile-butadiene rubber.
10. The variable displacement piston type compressor according to claim 1 , wherein the cam plate is inclinable swash plate for varying displacement of the compressor.
11. The variable displacement piston type compressor according to claim 1 , further comprising lubricant oil that fluids with the refrigerant therein.
12. A variable displacement piston type compressor comprising:
a cylinder block including a plurality of cylinder bores;
a piston for compressing refrigerant in each cylinder bore;
a cam plate movably connected to the piston for reciprocating the piston;
a crank chamber defined near one end of the cylinder block;
a drive shaft having a rotational axis for rotating to drive the cam plate, wherein the drive shaft is urged in a direction of the rotational axis while the piston reciprocates;
a suction chamber defined near the opposite end to the crank chamber relative to the cylinder block, the refrigerant in the suction chamber being drawn into the cylinder bores due to the suction work of the piston;
a discharge chamber defined near the opposite end to the crank chamber relative to the cylinder block, the refrigerant in the cylinder bores being discharged to the discharge chamber due to the discharge work of the piston; and
wherein the refrigerant in the discharge chamber is supplied into the crank chamber and the refrigerant in the crank chamber is bled into the suction chamber through a bleed passage for controlling pressure in the crank chamber, the bleed passage being formed outside of the drive shaft.
13. The variable displacement piston type compressor according to claim 12 , wherein at least a part of the bleed passage is formed in a shaft hole of the cylinder block through which the drive shaft extends.
14. The variable displacement piston type compressor according to claim 13 , wherein the drive shaft is rotatably supported by a radial bearing in the cylinder block, the radial bearing being placed in the bleed passage.
15. The variable displacement piston type compressor according to claim 12 , wherein the discharge chamber and the suction chamber are separated from the cylinder bores by a valve plate assembly, a part of the bleed passage extends through the cylinder block and the valve plate assembly, and a part of the bleed passage in the valve plate assembly is a throttled passage.
16. The variable displacement piston type compressor according to claim 12 , wherein the upstream end of the bleed passage is opened to the bottom of the crank chamber.
17. The variable displacement piston type compressor according to claim 16 , wherein the bleed passage passes through the cylinder block and then reaches the circumferential surface of the drive shaft, and the circumferential surface of the drive shaft and the bleed passage in the cylinder block meet more upward in a vertical direction than the central axis of the drive shaft.
18. The variable displacement piston type compressor according to claim 12 , further comprising a throttling means having a blocking member in the bleed passage and a throttled passage formed on the blocking member, the blocking member being made of resin or rubber.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JPP2001-244759 | 2001-08-10 | ||
JP2001244759A JP2003056460A (en) | 2001-08-10 | 2001-08-10 | Passage structure in variable displacement piston type compressor |
Publications (1)
Publication Number | Publication Date |
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US20030035732A1 true US20030035732A1 (en) | 2003-02-20 |
Family
ID=19074642
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US10/215,702 Abandoned US20030035732A1 (en) | 2001-08-10 | 2002-08-08 | Structure of channel in variable displacement piston type compressor |
Country Status (3)
Country | Link |
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US (1) | US20030035732A1 (en) |
EP (1) | EP1283360A3 (en) |
JP (1) | JP2003056460A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070081905A1 (en) * | 2005-10-06 | 2007-04-12 | Valeo Thermal Systems Japan Corporation | Piston-type compressor |
US20150159645A1 (en) * | 2013-12-11 | 2015-06-11 | Kabushiki Kaisha Toyota Jidoshokki | Variable displacement swash plate type compressor |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7178450B1 (en) | 2005-10-06 | 2007-02-20 | Delphi Technologies, Inc. | Sealing system for a compressor |
Citations (2)
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US6250891B1 (en) * | 1998-12-22 | 2001-06-26 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Variable displacement compressor having displacement controller |
US20010021348A1 (en) * | 2000-01-11 | 2001-09-13 | Masaki Ota | Piston type compressor and compressor assembly method |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH1162823A (en) * | 1997-08-08 | 1999-03-05 | Sanden Corp | Variable displacement compressor |
US6138468A (en) * | 1998-02-06 | 2000-10-31 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Method and apparatus for controlling variable displacement compressor |
JPH11294327A (en) * | 1998-04-14 | 1999-10-26 | Toyota Autom Loom Works Ltd | Capacity fixed swash plate type compressor |
US6352416B1 (en) * | 1999-03-15 | 2002-03-05 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Device and method for controlling displacement of variable displacement compressor |
JP2001012346A (en) * | 1999-06-29 | 2001-01-16 | Toyota Autom Loom Works Ltd | Reciprocating compressor |
JP3906432B2 (en) * | 1999-12-27 | 2007-04-18 | 株式会社豊田自動織機 | Air conditioner |
-
2001
- 2001-08-10 JP JP2001244759A patent/JP2003056460A/en active Pending
-
2002
- 2002-08-08 US US10/215,702 patent/US20030035732A1/en not_active Abandoned
- 2002-08-08 EP EP02017854A patent/EP1283360A3/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6250891B1 (en) * | 1998-12-22 | 2001-06-26 | Kabushiki Kaisha Toyoda Jidoshokki Seisakusho | Variable displacement compressor having displacement controller |
US20010021348A1 (en) * | 2000-01-11 | 2001-09-13 | Masaki Ota | Piston type compressor and compressor assembly method |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070081905A1 (en) * | 2005-10-06 | 2007-04-12 | Valeo Thermal Systems Japan Corporation | Piston-type compressor |
US8152481B2 (en) * | 2005-10-06 | 2012-04-10 | Valeo Thermal Systems Japan Corporation | Piston-type compressor |
US20150159645A1 (en) * | 2013-12-11 | 2015-06-11 | Kabushiki Kaisha Toyota Jidoshokki | Variable displacement swash plate type compressor |
US9551336B2 (en) * | 2013-12-11 | 2017-01-24 | Kabushiki Kaisha Toyota Jidoshokki | Variable displacement swash plate type compressor |
Also Published As
Publication number | Publication date |
---|---|
EP1283360A3 (en) | 2004-07-21 |
JP2003056460A (en) | 2003-02-26 |
EP1283360A2 (en) | 2003-02-12 |
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