JP2007198250A - Reciprocating type fluid machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating type fluid machine which can secure a return path of lubricating oil. <P>SOLUTION: The reciprocating type fluid machine is provided with a cylinder head (14) secured to one side of a cylinder block (46) via a valve plate (58) and having a discharge chamber (66) for working fluid containing the lubricating oil therein; a lubricating oil separation device (72) for separating the lubricating oil from the working fluid in the discharge chamber; and the return path (80) for returning the separated lubricating oil from the lubricating oil separation device to a crankcase (16). The return path includes a head communication passage (82) bored in the cylinder head, a plate communication passage (84) having a bottomed portion (85) within the valve plate, bored from the cylinder block side toward the cylinder head side and at least surrounding an outer peripheral position of each of a plurality of cylinder bores formed in the cylinder block, and a block communication passage (92) bored in the cylinder block. <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 And a return path for returning the lubricating oil separated from the crank chamber to the crank chamber. The return path has a head communication path drilled in the cylinder head and a bottom in the valve plate. And includes a plate communication path that at least surrounds the position of the outer peripheral side of each cylinder bore, and a block communication path that is formed in the cylinder block. .

Further, the invention according to claim 2 is characterized in that the plate communication passage is formed along the outer peripheral shape of the cylinder bore positioned outside the center of each cylinder bore.
Furthermore, the invention described in claim 3 is characterized in that the plate communication passage is formed so as to surround the entire circumference of each cylinder bore.
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 valve plate is provided with a plate communication passage surrounding the position on the outer peripheral side of each cylinder bore, and one end side of the plate communication passage. Communicates with the lubricating oil separator through the head communication path, and the other end communicates with the crank chamber through the block communication path. Therefore, the length of the return path in the valve plate is longer than the conventional one, and the return path can be secured without extremely reducing the diameter.

According to the second aspect of the present invention, since the lubricating oil in the return path reaches the block communication path along the path having a small flow path resistance, the length of the return path is surely increased as compared with the prior art. .
Furthermore, according to the invention described in claim 3, since the plate communication path is formed in a circular shape surrounding the entire circumference of each cylinder bore, the sealing performance by the lubricating oil is improved.

Furthermore, according to the fourth aspect of the present invention, the sealing performance of the valve plate 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 seven 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 that opens toward the front housing 12, and the opening end of the cylinder head 14 passes through the cylinder gasket 54, the metal suction reed valve 56, the metal valve plate 58, and the head gasket 60. And airtightly connected to the front housing 12 (FIG. 2). 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 via a suction hole such as a valve plate 58, and the suction hole is opened and closed by a suction reed valve 56 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 through 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 such as a valve plate 58, and this discharge hole is opened and closed by a discharge reed valve 62. 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, as shown in FIG. 1, the lubricating oil separation 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 the present embodiment is formed on the cylinder head 14 side, a head communication path 82 in which an orifice having a filter is inserted, and a plate communication path 84 formed in the valve plate 58 (FIG. 3). The lubricating oil separated from the lubricating oil separating device 72 is returned to the crank chamber 16 by a block communication path 92 formed on the cylinder block 46 side.
More specifically, the oil storage chamber 79 is connected to the head communication path 82, and the head communication path 82 also passes through the head gasket 60 and communicates with the plate communication path 84.

  The plate communication path 84 is shown in FIG. 10A is a front view of the valve plate 58 as viewed from the suction reed valve 56 side, and the head gasket 60 is in contact with the back side of the valve plate 58. FIG. Further, the plate communication path 84 is formed along the outer peripheral shape of the cylinder bore 48 positioned outside the center of the seven cylinder bores 48. Specifically, as shown in FIG. 5A, the plate communication path 84 has seven outer peripheral portions 86 along the outer peripheral shape of the cylinder bore 48 and six connection portions 88 that connect the outer peripheral portions 86. The one end 87 of the plate communication path 84 passes through the valve plate 58 and is connected to the head communication path 82 (FIG. 5B). The other end 90 of the plate communication path 84 is connected to a block communication path 92, and the block communication path 92 passes through the suction reed valve 56 and the cylinder gasket 54 and reaches the crank chamber 16. The plate communication path of the present invention may be formed so as to surround at least the outer peripheral side position of each cylinder bore 48 without being along the outer peripheral shape of the seven cylinder bores 48.

  On the other hand, the plate communication path 84 of the present embodiment also has seven inner peripheral portions 89 along the inner peripheral shape of the cylinder bore 48. In other words, the plate communication passage 84 is formed by surrounding the entire circumference of each cylinder bore 48 with the outer peripheral portion 86 and the inner peripheral portion 89 (FIG. 5A). The outer peripheral portion 86, the inner peripheral portion 89, and the connecting portion 88 do not penetrate the valve plate 58, and each have a bottomed portion 85 that is drilled from the suction reed valve 56 side toward the head gasket 60 side. ((B) in the figure).

  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 through the swash plate 40, and the reciprocating motion of each piston 50 is a suction in which the refrigerant in the suction chamber 64 is sucked into the cylinder bore 48 through the suction reed valve 56. A series of processes including a process, 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 62 is performed. 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 lubricating oil in the oil storage chamber 79 is returned toward the crank chamber 16 through the return path 80 based on the pressure difference between the oil storage chamber side 79 and the crank chamber side 16. Specifically, the lubricating oil that has reached one end 87 of the plate communication path 84 via the head communication path 82 passes through the valve plate 58 along the flow path with low resistance, that is, the outer peripheral portion 86 and the connection portion 88. To the other end 90. At the same time, the lubricating oil also flows along the inner peripheral portion 89. Then, the lubricating oil that has reached the other end 90 reaches the crank chamber 16 via the block communication path 92 and is used for lubricating the bearings 30 and 32 and the like.

  As described above, according to the present invention, the valve plate 58 is provided with the plate communication path 84 that surrounds the outer peripheral side position of each cylinder bore 48, and one end 87 of the plate communication path 84 serves as the head communication path. The other end 90 communicates with the crank chamber 16 through a block communication path 92. Therefore, the length of the return path in the valve plate 58 is longer than that in the prior art, and the return path can be secured without extremely reducing the diameter in the return path.

  Further, since the lubricating oil in the return path 80 reaches the block communication path 92 along the path (outer peripheral portion 86 and connection portion 88) with a low flow path resistance, the length of the return path is surely longer than that in the prior art. However, since the plate communication passage 84 is formed in an annular shape surrounding the entire circumference of each cylinder bore 48 (outer peripheral portion 86 and inner peripheral portion 89), the valve plate 58 and the suction reed valve 56 due to metal contact are formed. Sealing performance with lubricating oil is improved.

Furthermore, the sealing performance of the valve plate 58 is ensured even when a CO ₂ refrigerant having a high operating pressure is used, and the use of the CO ₂ refrigerant greatly contributes to the reduction of 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, in the above-described embodiment, the return path 80 is configured as a single continuous flow path, but may be configured from a plurality of flow paths. There is an effect of securing a return path.

  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 principal part enlarged view in the fluid machine of FIG. (A) is a front view of the valve | bulb plate of FIG. 1, (b) is arrow sectional drawing in the BB line of (a).

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 Head communication path 84 Plate communication path 85 Bottomed section 92 Block communication path

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 separation device to the crank chamber,
The return path includes a head communication path drilled in the cylinder head, a bottomed portion in the valve plate, and is drilled from the cylinder block side toward the cylinder head side. A reciprocating fluid machine comprising: a plate communication path that at least surrounds a position; and a block communication path formed in the cylinder block.   2. The reciprocating fluid machine according to claim 1, wherein the plate communication path is formed along an outer peripheral shape of the cylinder bore located outside a center of each cylinder bore.   The reciprocating fluid machine according to claim 2, wherein the plate communication passage is formed so as to surround the entire circumference of each cylinder bore. 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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