JP2007192154A - Reciprocating fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating fluid machine capable of securing the return route of lubricating oil. <P>SOLUTION: A reciprocating fluid machine includes a cylinder head (14) having a discharge chamber (66) fixed at one side of a cylinder block (46), and situated in the interior thereof; a lubricating oil separating device (72) for separating working fluid of discharge chamber from lubricating oil; a casing (12) having a crank chamber (16) in which a swash plate (40) that is extended toward the other side of the cylinder block, and performs rotating motion integral with a rotating shaft (18) is arranged in the interior thereof; a cylinder bore (48) drilled in plural in the cylinder block, and having a piston (50) that performs reciprocating motion in the interior thereof along with rotating motion of the swash plate; and a flow rate regulating valve (82) disposed in a return passage (80) for returning lubricating oil separated from the lubricating oil separating device to the crank chamber, and opened and closed in response to differential pressure between the discharge chamber and the crank chamber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reciprocating fluid machine, and more particularly, to a reciprocating fluid machine using a refrigerant having a high working pressure.

  The reciprocating fluid machine is used as, for example, a compressor for a refrigeration circuit, and compresses a refrigerant. Usually, the refrigerant contains lubricating oil. Lubricating oil in the refrigerant not only lubricates the sliding surfaces and bearings in the compressor, but also functions as a seal for the sliding surfaces (see, for example, Patent Document 1). However, when this lubricating oil circulates in the refrigeration circuit, it becomes a factor of reducing the cooling capacity of the refrigeration circuit.

For this reason, there is a compressor that has a lubricating oil separation device that separates compressed refrigerant and lubricating oil from the discharge chamber and returns the lubricating oil to the crank chamber via a return path (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 11-223179 JP 2001-27177 A

  By the way, the above-mentioned Patent Document 1 is a compressor having a control valve for connecting a discharge chamber and a crank chamber, and returning lubricating oil in the discharge chamber to the crank chamber in accordance with opening and closing of the control valve. Specifically, the amount of return of the lubricant to the crank chamber depends on the opening / closing operation of the control valve, and the lubricant is returned to the crank chamber together with the compressed refrigerant when the control valve is opened. When the control valve is fully closed as described above, there is a problem that the lubricating oil does not return to the crank chamber.

On the other hand, in the case of the compressor having the lubricating oil separation device described in Patent Document 2, it does not depend on the opening / closing operation of the control valve. However, when natural CO ₂ (carbonic acid) gas is used as a refrigerant, problems still arise. In other words, the return path in this case has a filter and an orifice that regulates the return amount to the crank chamber, and the filter and the orifice are clogged, and it is difficult for the lubricating oil to return to the crank chamber. is there. This is because the operating region of the CO ₂ refrigerant is used in the supercritical region on the high pressure side, and this operating pressure is higher than that of the chlorofluorocarbon refrigerant, so the diameter of the filter and orifice must be extremely small. .

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a reciprocating fluid machine capable of ensuring a return path for lubricating oil.

  In order to achieve the above object, a reciprocating fluid machine according to claim 1 is fixed to one side of a cylinder block via a valve plate, and has a discharge chamber for a working fluid containing lubricating oil inside thereof, A cylinder head having a lubricating oil separation device that separates the working fluid and lubricating oil in the discharge chamber, and a swash plate that extends toward the other side of the cylinder block and rotates integrally with the rotating shaft are disposed therein. A casing having a crank chamber, a cylinder bore having a plurality of holes concentrically with respect to the cylinder block, and having a piston that reciprocates inside the cylinder block as the swash plate rotates, and a lubricating oil separating device A return path for returning the lubricating oil separated from the crank chamber to the crank chamber, and a flow rate control valve disposed in the return path and opened and closed in accordance with a differential pressure between the discharge chamber and the crank chamber. It is characterized in that.

In the invention according to claim 2, the flow rate control valve is disposed so as to be slidable with respect to the valve hole, the valve main body having a valve hole whose diameter is expanded toward the direction away from the crank chamber, and the crank chamber. And a valve member having a valve body that is reduced in diameter.
Furthermore, in the invention according to claim 3, when the pressure in the discharge chamber is much higher than the pressure in the crank chamber, the valve body closes the valve hole, while the pressure in the discharge chamber is When the pressure is approximately equal to the pressure, the valve element is characterized by opening the valve hole at the maximum diameter.

Furthermore, the invention according to claim 4 is characterized in that the reciprocating fluid machine is inserted in a circulation path of a refrigeration circuit using CO ₂ refrigerant.

Therefore, according to the reciprocating fluid machine of the first aspect of the present invention, the control valve dedicated to the lubricating oil is disposed in the return path for returning the separated lubricating oil to the crank chamber. Therefore, a return path can be secured without providing a control valve for returning together with the compressed refrigerant as in the prior art, or without making the diameter of the orifice or the like extremely small, and the return amount of the lubricating oil to the crank chamber is secured.
According to the invention of claim 2 or claim 3, the valve body has a valve hole whose diameter is increased toward the direction away from the crank chamber, and the valve member is reduced in diameter toward the crank chamber. A valve body is provided, and the contact length between the valve hole and the valve body, that is, the opening diameter of the valve hole is changed according to the pressure difference between the pressure in the discharge chamber and the pressure in the crank chamber. As a result, the influence of the difference in pressure between the discharge pressure and the crank pressure is less affected than in the prior art, and the amount of return to the crank chamber is made constant.

Furthermore, according to the fourth aspect of the invention, the amount of return of the lubricating oil to the crank chamber is ensured even when a CO ₂ refrigerant having a high operating pressure is used. In addition, if a CO ₂ refrigerant is used, it greatly contributes to the reduction of the environmental load.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the present embodiment is applied to a swash plate type variable displacement compressor (reciprocating fluid machine) 4 using a CO ₂ refrigerant, and the compressor 4 is a vehicle air conditioner. It is configured as one device of the refrigeration circuit. Specifically, a compressor 4, a gas cooler, an expansion valve, and an evaporator are sequentially inserted in the refrigeration circuit. The refrigerant contains lubricating oil, and this lubricating oil not only lubricates the bearings and various sliding surfaces in the compressor 4 but also functions to seal the sliding surfaces.

The compressor 4 includes a front housing (casing) 12, and a cylinder head 14 is joined to the rear side of the front housing 12. The front housing 12 and the cylinder head 14 are inserted into bolt holes 67. It is connected by a plurality of bolts 68.
More specifically, the front housing 12 has a cylindrical shape with a large diameter toward the cylinder head 14, and has both open ends. A crank chamber 16 is formed in the front housing 12. A shaft (rotary shaft) 18 is disposed in the crank chamber 16. The shaft 18 does not have a stepped shape, one end thereof protrudes from the front housing 12, and a driving disk 20 is attached to the protruding end via a nut 22. Specifically, the drive disk 20 is disposed so as to be connectable to a drive pulley 26 via an electromagnetic clutch 24, and the drive pulley 26 is rotatably supported on the front housing 12 via a bearing 28.

  When the electromagnetic clutch 24 is turned ON, the electromagnetic clutch 24 integrally connects the drive pulley 26 and the drive disk 20 and rotates the shaft 18 together with the drive pulley 26 in one direction. On the other hand, when the electromagnetic clutch 24 is turned off, the electromagnetic clutch 24 releases the connection between the drive pulley 26 and the drive disk 20 and cuts off the transmission of power from the drive pulley 26 to the shaft 18.

  The shaft 18 is rotatably supported in the front housing 12 via bearings 30 and 32. Further, in the front housing 12, a lip seal 34 is disposed between one end side of the shaft 18 and the bearing 30, and the lip seal 34 partitions the crank chamber 16 in an airtight manner. Further, a disk-shaped rotor 36 is fixed to the shaft 18, and a bearing 38 is disposed on the back side of the rotor 36. An arm 42 that transmits the rotation of the shaft 18 to the swash plate 40 is fixed to the shaft 18, and the rotor 36 and the arm 42 are connected via a hinge 44. The swash plate 40 described above is configured to be tiltable with respect to a virtual plane orthogonal to the rotation axis of the shaft 18, and the swash plate 40 swings outside the shaft 18.

  A cylinder block 46 is disposed in the front housing 12. The cylinder block 46 may be integrally formed with the front housing 12. The cylinder block 46 is provided with a plurality of cylinder bores 48 at predetermined intervals in the circumferential direction around the shaft 18, and a piston 50 is accommodated in each cylinder bore 48. The piston 50 has a tail protruding from the cylinder bore 48, and a pair of shoes 52 sandwiching the outer peripheral edge of the swash plate 40 are held by the tail. The swash plate 40 is in sliding contact with the inner surface of the shoe 52 when rotating.

Thereby, when the rotation of the drive pulley 26 is transmitted to the shaft 18, the shaft 18 rotates the swash plate 40 via the arm 42. The rotational movement of the swash plate 40 is converted into the reciprocating motion of the piston 50 via the shoe 52. On the other hand, when the inclination angle of the swash plate 40 is changed, the stroke amount of the piston 50 is changed, and as a result, the discharge capacity of the compressor 4 is adjusted.
The cylinder head 14 has a cup shape opened toward the front housing 12, and the opening end thereof is airtightly connected to the cylinder block 46 and the front housing 12 via the valve plate 58. A refrigerant suction chamber 64 and a discharge chamber 66 are formed in the cylinder head 14, and the suction chamber 64 is disposed around the discharge chamber 66. The suction chamber 64 can communicate with each cylinder bore 48 through a suction hole of the valve plate 58, and the suction hole is opened and closed by a suction reed valve (not shown) that is opened and closed from the cylinder bore 48 side. The crank chamber 16 and the suction chamber 64 are always in communication with each other via a passage 70 formed in the cylinder head 14, the valve plate 58 and the cylinder block 46. The passage 70 has a fixed throttle in the middle thereof, and can gradually release the pressure in the crank chamber 16 toward the suction chamber 64 side.

  On the other hand, the discharge chamber 66 communicates with each cylinder bore 48 through a discharge hole of the valve plate 58, and this discharge hole is opened and closed by a discharge reed valve (not shown). This discharge reed valve is attached to the discharge chamber 66 side with a bolt 63 together with a bolt. The discharge chamber 66 and the crank chamber 16 communicate with each other via a passage (not shown), and this passage is configured to be opened and closed by an electromagnetic control valve (not shown). Thereby, the said discharge capacity is adjusted and the blowing temperature from an evaporator is controlled uniformly.

Although not shown, a suction port and a discharge port are formed in the peripheral wall of the cylinder head 14, and the suction port is connected to the evaporator and communicated with the suction chamber 64. On the other hand, the discharge port communicates with the discharge chamber 66 via the lubricating oil separator 72 and is connected to a gas cooler.
Specifically, the lubricating oil separating device 72 is disposed between the discharge chamber 66 and the discharge port. The lubricating oil separation device 72 has a separation chamber 78, and a separation pipe 76 is press-fitted and fixed to the separation chamber 78 from above. An annular space is formed between the inner peripheral surface of the separation chamber 78 and the outer peripheral surface of the separation pipe 76, and a refrigerant jet that communicates the discharge chamber 66 and the annular space at an appropriate position of the cylinder head 14. A hole 74 is formed. Further, an oil storage chamber 79 is formed below the separation chamber 78, and the oil storage chamber 79 and the crank chamber 16 communicate with each other via a return path 80.

The return path 80 of this embodiment includes an oil flow rate control valve (flow rate control valve) 82 disposed in the cylinder head 14, and a block communication path 96 formed in the valve plate 58 and the cylinder block 46. The lubricating oil separated by the lubricating oil separation device 72 is returned to the crank chamber 16.
This oil flow rate control valve 82 is opened and closed in accordance with the differential pressure between the oil storage chamber 79 communicating with the discharge chamber 66 and the crank chamber 16, and as shown in FIG. The housing 84 includes a valve main body 87 and a valve member 90 disposed in the valve housing 84, and a spring 94 sandwiched between the valve main body 87 and the valve member 90.

More specifically, the valve housing 84 is formed in a cylindrical shape having openings at both ends thereof, and has a stopper 85 at the end facing the oil storage chamber 79, and the inside of the stopper 85 defines the movement range of the valve member 90. It is regulated. An introduction port 86 is formed on the inner peripheral side of the stopper 85, and the lubricating oil in the oil storage chamber 79 is introduced toward the crank chamber 16.
The valve main body 87 is integrally fixed to the valve housing 84 and has a diameter-enlarged valve hole (valve hole) 88 at the center thereof. The diameter-enlarged valve hole 88 communicates with the block communication passage 96 and is gradually increased in diameter from the cylinder block 46 side toward the cylinder head 14 side, that is, in a direction away from the crank chamber 16. Further, the valve body 87 has a flange portion 89 at the outer peripheral end position, and this flange portion 89 functions as a spring seat of the spring 94.

  On the other hand, the valve member 90 is movably disposed in the valve housing 84 and has a reduced-diameter valve body (valve body) 91 at the center thereof. The diameter-reduced valve body 91 is gradually reduced in diameter from the cylinder head 14 side toward the cylinder block 46 side, that is, toward the crank chamber 16, and is slidably disposed with respect to the diameter-enlarged valve hole 88. . Further, the valve member 90 has a flange portion 92 at the outer peripheral end position, and this flange portion 92 also functions as a spring seat of the spring 94. Further, an annular introduction hole 93 is formed at an appropriate position of the flange portion 92 and communicates with the introduction port 86.

Further, the spring 94 held between the flange portions 89 and 92 urges the valve main body 87 and the valve member 90 in the valve housing 84 in the direction of separating them.
In the compressor 4 described above, when the electromagnetic clutch 24 is turned ON, the shaft 18 is rotated by the external power transmitted through the electromagnetic clutch 24. The rotation of the shaft 18 is converted into a reciprocating motion of the piston 50 via the swash plate 40, and the reciprocating motion of each piston 50 is a suction process in which the refrigerant in the suction chamber 64 is sucked into the cylinder bore 48 via the suction reed valve. And a series of processes including a compression process in which the refrigerant is compressed in the cylinder bore 48 and a discharge process in which the compressed refrigerant is discharged into the discharge chamber 66 through the discharge reed valve. The refrigerant discharge capacity is adjusted by controlling the pressure in the crank chamber 16 by opening / closing the electromagnetic control valve and increasing / decreasing the stroke length of the piston 50.

  The compressed refrigerant in the discharge chamber 66 passes through the refrigerant ejection hole 74 and flows into the separation chamber 78, and descends while turning around the outer peripheral surface of the separation pipe 76. In this process, the compressed refrigerant rises through the separation pipe 76 to reach the discharge port, and is sent out from the discharge port 76 toward the gas cooler. On the other hand, the lubricating oil in the compressed refrigerant is separated from the refrigerant based on the principle of centrifugal separation, flows down along the inner peripheral surface of the separation chamber 78, and the lubricating oil is guided to the oil storage chamber 79 and stored. .

  Here, the oil storage chamber 79 is always in communication with the discharge chamber 66 via the separation chamber 78, and the lubricating oil in the oil storage chamber 79 is based on the pressure difference between the oil storage chamber side 79 and the crank chamber side 16. When the oil flow control valve 82 is activated, the oil flow control valve 82 is returned toward the crank chamber 16 through the return path 80. Specifically, when the discharge pressure Pd is much higher than the crank pressure Pc, the reduced diameter valve body 91 moves toward the crank chamber 16 against the urging force of the spring 94 as shown in FIG. To do. As a result, the gap between the diameter-reduced valve element 91 and the diameter-enlarged valve hole 88 is minimized, the diameter-enlarged valve hole 88 is closed, and the return amount of the lubricating oil to the crank chamber 16 does not increase.

  On the other hand, when the discharge pressure Pd is slightly larger than the crank pressure Pc, the diameter-reduced valve body 91 moves in a direction away from the crank chamber 16 by the urging force of the spring 94. As a result, a gap between the diameter-reduced valve body 91 and the diameter-enlarged valve hole 88 is generated, and the diameter-enlarged valve hole 88 is slightly opened. Therefore, the lubricating oil in the oil storage chamber 79 is introduced into the inlet 86, the inlet hole 93, and the block. It reaches the crank chamber 16 through the communication passage 96 and is used for lubricating the bearings 30 and 32.

  Further, when the discharge pressure Pd is substantially equal to the crank pressure Pc, as shown in FIG. 3, the diameter-reduced valve body 91 moves in the direction farthest away from the crank chamber 16 by the biasing force of the spring 94. Thereby, the clearance gap between the diameter-reduced valve body 91 and the diameter expansion valve hole 88 becomes the largest, and the diameter expansion valve hole 88 is opened by the maximum aperture. As a result, the return amount to the crank chamber 16 becomes the maximum amount, and the lubricating oil in the oil storage chamber 79 is most used for lubrication of the bearings 30 and 32 and the like.

  As described above, according to the present invention, the oil flow control valve 82 dedicated to the lubricating oil is disposed in the return path 80 for returning the separated lubricating oil to the crank chamber 16. Therefore, the return path 80 can be ensured without providing a control valve that returns together with the compressed refrigerant as in the prior art or the diameter of the orifice or the like is made extremely small, and the return amount of the lubricating oil to the crank chamber 16 is ensured.

  Further, the valve body 87 has a diameter-enlarged valve hole 88 whose diameter is increased in a direction away from the crank chamber 16, and the valve member 90 has a diameter-reduced valve body 91 whose diameter is reduced toward the crank chamber 16. The contact length between the diameter-enlarged valve hole 88 and the diameter-reduced valve body 91, that is, the opening diameter of the diameter-enlarged valve hole 88 is changed according to the differential pressure between the discharge pressure Pd and the crank pressure Pc. Is done. As a result, the influence of the differential pressure between the discharge pressure Pd and the crank pressure Pc is less affected than in the prior art, and the return amount to the crank chamber 16 is made constant.

Furthermore, even if a CO ₂ refrigerant having a high operating pressure is used, the return amount of the lubricating oil to the crank chamber 16 is ensured, and the use of the CO ₂ refrigerant greatly contributes to reducing the environmental load.
The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the oil flow control valve 82 may be disposed in the cylinder block 46 in addition to the cylinder head 14 described above, and the oil flow control valve 82 is an electromagnetic control valve that is opened and closed by detecting the discharge pressure Pd and the like. It may be. In these cases as well, as described above, there is an effect of securing a return path for the lubricating oil.

  Needless to say, the reciprocating fluid machine of the present invention can be similarly applied to a fixed capacity compressor or expander.

1 is a longitudinal sectional view of a reciprocating fluid machine according to an embodiment of the present invention. It is a figure which shows the time of valve closing of the oil flow control valve of FIG. It is a figure which shows the time of valve opening of the oil flow control valve of FIG.

Explanation of symbols

4 compressor (reciprocating fluid machine)
12 Front housing (casing)
14 Cylinder head 16 Crank chamber 18 Shaft (Rotating shaft)
40 Swash Plate 46 Cylinder Block 48 Cylinder Bore 50 Piston 58 Valve Plate 66 Discharge Chamber 72 Lubricating Oil Separator 80 Return Path 82 Oil Flow Control Valve (Flow Control Valve)
87 Valve body 88 Expanded valve hole (valve hole)
90 Valve member 91 Reduced diameter valve element (valve element)

Claims (4)

A lubricating oil separation device fixed to one side of the cylinder block via a valve plate, having a working fluid discharge chamber containing lubricating oil therein, and separating the working fluid and the lubricating oil in the discharge chamber A cylinder head having,
A casing having a crank chamber that extends toward the other side of the cylinder block and in which a swash plate that rotates integrally with a rotating shaft is disposed;
A cylinder bore having a piston concentrically with respect to the cylinder block and having a piston that reciprocates inside the swash plate as the swash plate rotates;
A return path for returning the lubricating oil separated from the lubricating oil separator to the crank chamber;
A reciprocating fluid machine comprising a flow rate control valve disposed in the return path and opened and closed according to a pressure difference between the discharge chamber and the crank chamber.   The flow rate control valve is disposed so as to be slidable with respect to the valve hole, and has a valve body having a diameter increased in a direction away from the crank chamber, and is reduced in diameter toward the crank chamber. The reciprocating fluid machine according to claim 1, further comprising: a valve member having a valve body.   When the pressure in the discharge chamber is much larger than the pressure in the crank chamber, the flow control valve closes the valve hole while the pressure in the discharge chamber is substantially equal to the pressure in the crank chamber. The reciprocating fluid machine according to claim 2, wherein the valve body opens the valve hole with a maximum diameter when they are equal. The reciprocating fluid machine according to claim 1, wherein the reciprocating fluid machine is inserted in a circulation path of a refrigeration circuit using CO ₂ refrigerant.

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