JP2006097587A - Reciprocating compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating compressor preventing lubricating oil reaching a delivery chamber from flowing out to a refrigerant circulation route and surly securing lubricating oil in a crank chamber. <P>SOLUTION: This compressor is provided with a cylinder block 12, a crank case 14 provided with a crank chamber 74 and closing one end of the cylinder block, a cylinder head 16 gripping a valve plate 56, closing another end of the cylinder block, provided with a suction chamber 70 at a center part, provided with a delivery chamber 66 formed in an outer circumference side of the suction chamber and having a function separating lubricating oil from working fluid, and a connecting means 18 penetrating through the cylinder block and connecting the cylinder block and the cylinder head. A gap 88 returning lubricating oil in the delivery chamber toward the crank chamber is provided around the connecting means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a reciprocating compressor, and more particularly to a reciprocating compressor suitable for being incorporated in a refrigeration circuit of an air conditioning system of a vehicle.

This type of compressor for a refrigeration circuit compresses a refrigerant as a working fluid, and this refrigerant usually contains lubricating oil. The lubricating oil in the refrigerant not only lubricates the sliding surfaces and bearings in the crank chamber of the compressor, but also functions as a seal for the sliding surfaces. That is, a predetermined amount of lubricating oil must be secured in the crank chamber.
On the other hand, the reciprocating compressor is configured such that the crank chamber and the suction chamber are always in communication with each other via a communication path, and the pressure in the crank chamber is gradually released toward the suction chamber. Therefore, in order to ensure a predetermined amount of lubricating oil in the crank chamber, a large amount of lubricating oil is enclosed in the crank chamber in advance, or the communication path is improved to prevent the lubricating oil from flowing out from the crank chamber to the suction chamber. Are disclosed (Patent Documents 1 and 2).
JP-A-10-196529 JP 2003-97423 A

  By the way, when this lubricating oil circulates in the refrigeration circuit, it becomes a factor of reducing the cooling capacity of the refrigeration circuit. In other words, even if a large amount of lubricating oil is enclosed in the crank chamber in advance as described above, the refrigerant in the crank chamber flows out into the suction chamber, and the lubricating oil flows out into the suction chamber together with this refrigerant. Then, this lubricating oil is sucked and compressed together with the refrigerant in the suction chamber, and the compressed refrigerant and lubricating oil are sent to the circulation path of the refrigeration circuit through the discharge chamber. ) Increases and the cooling capacity decreases.

Therefore, it is conceivable to prevent the lubricating oil from flowing into the suction chamber by improving the communication path connecting the crank chamber and the suction chamber as in the prior art.
However, in solving this problem, it should be noted that the lubricating oil in the crank chamber is likely to flow out not only from the communication path but also from, for example, between the cylinder bore and the piston toward the discharge chamber. I must. This is because the lubricating oil reaches the discharge chamber from the crank chamber and is sent from the discharge chamber to the circulation path even if the outflow of the lubricating oil from the crank chamber to the suction chamber is prevented by improving the communication path. .

In addition, as the rotational speed of the compressor increases, the amount of refrigerant and lubricating oil flowing out from the crank chamber and suction chamber toward the discharge chamber increases, and the amount of lubricating oil in the crank chamber further decreases. That is, there is a problem that the cooling capacity and the durability of the compressor are particularly deteriorated in this high rotation region.
Thus, with the improved communication path configuration, the outflow of lubricating oil from the crank chamber to the suction chamber can be improved, but the lubricating oil that has reached the discharge chamber is sent to the circulation path. There is no special consideration. In addition, in view of the fact that a large amount of refrigerant and lubricating oil reach the discharge chamber from the crank chamber, particularly in the high rotation region, there still remains a problem with respect to securing the lubricating oil reliably in the crank chamber. ing.

  The present invention has been made in view of such a problem, and prevents the lubricating oil that has reached the discharge chamber from flowing out into the refrigerant circulation path, so that the lubricating oil can be reliably secured in the crank chamber. An object is to provide a compressor.

  In order to achieve the above object, the reciprocating compressor according to claim 1 compresses the working fluid sucked from the refrigeration circuit through the suction chamber, and adjusts the pressure of the working fluid including the lubricating oil in the crank chamber. A compressor that changes the discharge capacity and discharges the compressed working fluid into the discharge chamber. The compressor includes a cylinder block, a crank chamber, a crank case that closes one end of the cylinder block, and a valve plate. A cylinder head having a discharge chamber that closes the other end of the cylinder block, has a suction chamber at its center, and is formed on the outer peripheral side of the suction chamber and has a function of separating lubricating oil from the working fluid; A connecting means for penetrating and connecting the cylinder block and the cylinder head. Around the connecting means, the lubricating oil in the discharge chamber is returned from the discharge chamber toward the crank chamber. It is characterized in that gap to is provided.

In the second aspect of the present invention, a gasket is disposed on the surface of the valve plate on the cylinder head side between the other end of the cylinder block and the cylinder head, and the gap is formed by a groove disposed in the gasket. Further, it is characterized in that it is composed of pores arranged on the outer peripheral side of the connecting means.
Further, the invention described in claim 3 is characterized in that the connecting means is inserted from the crankcase side toward the cylinder head and connects the crankcase and the cylinder head through the cylinder block.

Furthermore, in the invention described in claim 4, the flow rate in the gap is set to a gas flow rate of 10 to 500 cc / min when the pressure difference between the discharge chamber and the crank chamber is 5 to 30 kg / cm ^2. It is characterized by.

  The present invention focuses on preventing the lubricating oil that has reached the discharge chamber from flowing out of the discharge chamber into the refrigerant circulation path and securing the amount of lubricating oil in the crank chamber. That is, according to the reciprocating compressor of the present invention described in claim 1, the cylinder block and the cylinder head are connected by the connecting means, and around the connecting means, the discharge chamber in the cylinder head extends from the discharge chamber in the crankcase. A gap for returning the lubricating oil in the discharge chamber toward the crank chamber is provided. Therefore, the lubricating oil is separated from the working fluid in the discharge chamber, and this lubricating oil is returned from the discharge chamber to the crank chamber through the gap, so that the lubricating oil that has reached the discharge chamber is sent to the refrigerant circulation path. Suppressing and ensuring that this lubricating oil is secured in the crank chamber.

As a result, for example, even in the high-speed rotation region of the compressor, the lubricating oil is stably supplied into the crank chamber, and not only lubrication of the sliding surfaces and bearings in the compressor, but also functions as a seal for the sliding surfaces It will be possible to demonstrate. In other words, the life of the compressor can be extended.
Further, since this lubricating oil is reliably returned to the crank chamber, it becomes difficult for the lubricating oil to circulate through the refrigerant circulation path, and the lubricating oil ratio (OCR) flowing through the refrigeration circuit is further suppressed. Thereby, the fall of the cooling capability is prevented further.

Furthermore, the amount of lubricating oil to be enclosed in the crank chamber in advance is also reduced, leading to a reduction in the operating cost of the compressor.
Further, according to the invention described in claim 2 and the invention described in claim 3, the lubricating oil can be returned to the crank chamber without making a major change to the compressor, and the manufacturing cost of the compressor can be reduced.

  Furthermore, according to the invention described in claim 4, in the normal operation state of the compressor, the loss of the lubricating oil is reduced, and it is also avoided that a large amount of the lubricating oil is secured, thereby improving the performance of the compressor. Contribute.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a swash plate compressor according to an embodiment of a reciprocating compressor. The compressor 2 is incorporated in a refrigeration circuit of a vehicle air conditioning system. Specifically, a compressor 2, a condenser 6, an expansion valve 8, and an evaporator 10 are sequentially arranged in the refrigerant circulation path 4 of this refrigeration circuit, and the compressor 2 serves as a working fluid from the return path of the refrigerant circulation path 4. The refrigerant is sucked, compressed, and discharged toward the forward path of the refrigerant circulation path 4. The refrigerant contains lubricating oil, and the lubricating oil in the refrigerant not only lubricates the bearings and various sliding surfaces in the compressor 2 but also functions to seal the sliding surfaces.

  The compressor 2 includes a cylinder block 12. One end of the cylinder block 12 is closed by a crankcase 14 and the other end is closed by a cylinder head 16. The crankcase 14 and the cylinder head 16 are inserted from the crankcase 14 side toward the cylinder head 16 and are connected by a plurality of connecting bolts (connecting means) 18 penetrating the cylinder block 12.

  A drive shaft 20 is disposed in the center of the crankcase 14, and one end side of the drive shaft 20 penetrates the crankcase 14 and is rotatably supported by the crankcase 14 via a bearing 22. On the other hand, the other end of the drive shaft 20 enters a center hole 24 formed through the center of the cylinder block 12 and is rotatably supported by the cylinder block 12 via a bearing 26.

A drive pulley 28 is attached to one end of the drive shaft 20 via a bolt 30. The drive pulley 28 is rotatably supported by the crankcase 14 via a bearing 32, and is rotated by receiving power from a vehicle engine (not shown). Accordingly, as the engine is driven, the rotation of the drive pulley 28 is transmitted to the drive shaft 20, and the drive shaft 20 is rotated in one direction.
For example, seven cylinder bores 34 are formed in the cylinder block 12. These cylinder bores 34 are arranged at equal intervals in the circumferential direction of the cylinder block 12, and penetrate the cylinder block 12 in the axial direction in parallel with the drive shaft 20.

Pistons 36 are slidably fitted in the cylinder bores 34, and one end of each piston 36 is formed as a tail 38 protruding from the cylinder block 12 into the crankcase 14, that is, into the crank chamber 74. The tail 38 has a pair of shoes 40, and the outer peripheral edge portion of the swash plate 42 is slidably sandwiched between the shoes 40.
The swash plate 42 is attached to the drive shaft 20, and a rotor 44 positioned between the crankcase 14 and the swash plate 42 is attached to the drive shaft 20. The swash plate 42 and the rotor 44 rotate integrally with the drive shaft 20, and the swash plate 42 is connected to the rotor 44 via a hinge 46 so as to be tiltable according to contact with the ring 48. Further, a coil spring 50 is attached to the drive shaft 20 so as to surround the drive shaft 20, and the coil spring 50 presses the swash plate 42 toward the cylinder block 16 according to the reciprocating linear motion of the piston 36. Energized.

  On the other hand, a circular valve plate 56 is sandwiched between the cylinder block 16 and the cylinder head 12 via a front gasket 52 and a rear gasket (gasket) 54, and the valve plate 56 is disposed in each cylinder bore 34. A compression chamber 58 is formed between the other end of the piston 36 and the front gasket 52. A discharge port 60 and a suction port 62 are formed in the valve plate 56 for each cylinder bore 34. Further, the communication path 64 is formed in the central portion of the valve plate 56. That is, when viewed in the radial direction of the valve plate 56, the suction port 62 is positioned outside the communication path 64, and the discharge port 60 is positioned outside the suction port 62.

  The cylinder head 16 has a cup shape opened toward the cylinder block 12, and the open end of the cup shape is airtightly fitted to the valve plate 56 via the rear gasket 54 and connected to the cylinder block 12. The cylinder head 16 has an annular discharge chamber 66 and a suction chamber 70 which are independent from each other. That is, the suction chamber 70 is disposed at the center of the cylinder head 16, and the discharge chamber 66 is disposed so as to surround the outer peripheral side thereof.

  The suction chamber 70 communicates with the compression chamber 58 of each cylinder bore 34 via a suction port 62, and the suction port 62 is opened and closed by a suction valve 72 provided in the front gasket 52. The suction chamber 70 is always in communication with the crank chamber 74 via the central hole 24 and the communication path 64 provided in the cylinder block 12. The communication path 64 has a throttle in the middle, and can gradually release the pressure in the crank chamber 74 to the suction chamber 70 side.

On the other hand, the discharge chamber 66 communicates with the compression chamber 58 of each cylinder bore 34 via the discharge port 60, and the discharge port 60 is opened and closed by the discharge valve 68 from the discharge chamber 66 side. The discharge valve 68 is provided in the rear gasket 54 and is formed integrally with the retainer.
Further, the discharge chamber 66 communicates with the crank chamber 74, and an electromagnetic control valve 76 is inserted in the middle of the communication. The electromagnetic control valve 76 is actuated by an output signal from the air conditioner ECU 78. The air conditioner ECU 78 includes an input / output device, a memory (ROM, RAM, nonvolatile RAM, etc.), a CPU, and the like. The air conditioner ECU 78 performs comprehensive control including capacity control of the compressor 2. . The refrigerant in the discharge chamber 66 is supplied to the crank chamber 74 via the connection paths 80 and 82 in accordance with the opening / closing operation by the electromagnetic control valve 76.

A discharge passage 84 and a suction passage 86 communicating with the discharge chamber 66 and the suction chamber 70 are formed on the peripheral wall of the cylinder head 16. The suction passage 86 is connected to the return path of the circulation path 4, and the discharge path 84 is connected to the circulation path. 4 are connected to the forward path.
On the other hand, the outer peripheral area of the discharge chamber 66 and the crank chamber 74 communicate with each other via a return gap (gap) 88.

Details of the return gap 88 are shown in FIG.
The return gap 88 is disposed around the connecting bolt 18, and returns the lubricating oil flowing out from the suction chamber 70 and the crank chamber 74 to the discharge chamber 66 toward the crank chamber 74. More specifically, the return gap 88 of the present embodiment includes a communication groove (groove) 90 disposed in the rear gasket 54 and a communication pore (pore) 92 disposed around the connection bolt 18. It is composed of

  As shown in FIG. 3 when viewed from the cylinder head 16 side, the rear gasket 54 is provided with a discharge valve 68 and a suction port 62 corresponding to the positions of the seven cylinder bores 34, and between these adjacent discharge valves 68. Bolt holes 94 are provided in the main body. The bolt hole 94 is engaged with the connecting bolt 18. The numbers of the connecting bolts 18 and the bolt holes 94 can be set as appropriate, and are not limited to the illustrated numbers. Reference numeral 96 is a positioning hole for the valve plate 56.

  The communication groove 90 extends from the bolt hole 94 toward the center of the rear gasket 54. Specifically, one end side of the communication groove 90 reaches the opening periphery of the bolt hole 94, and the other end side of the communication groove 90 reaches the inside of the discharge chamber 66. On the other hand, the bolt hole 94 communicating with the communication groove 90 is the outer peripheral side of the connection bolt 18, that is, in this embodiment, the communication hole 92 provided in the valve plate 56, the front gasket 52, and the cylinder block 12. Further, the communication pore 92 reaches the crank chamber 74.

In the present embodiment, the flow rate in the return gap 88 constituted by the communication groove 90 and the communication pore 92 is about 10 when the pressure difference between the discharge chamber 66 and the crank chamber 74 is about 5 to 30 kg / cm ² . The gas flow rate is set to 500 cc / min.
When the heat load of the refrigeration cycle increases and the electromagnetic control valve 76 is excited by an output signal from the air conditioner ECU 78, the pressure in the discharge chamber 66 is not supplied to the crank chamber 74. On the other hand, the pressure in the crank chamber 74 is gradually released to the suction chamber 70 via the throttle in the communication passage 64, so that it gradually decreases and the back pressure applied to the piston 36 also decreases. Thereby, the inclination | tilt angle of the swash plate 42 becomes large. When the compressor 2 is required to operate at the maximum capacity, the swash plate 42 rotates with the maximum inclination angle.

  The rotation of the swash plate 42 is converted into a reciprocating linear motion of each piston 36. Here, when the piston 36 moves in the direction of increasing the compression chamber 58 in the cylinder bore 34, the suction valve 72 is opened, and the refrigerant gas is sucked from the suction chamber 70 through the suction port 62. Lubricating oil that has flowed out of the crank chamber 74 into the suction chamber 70 is also sucked together with the refrigerant gas. Thereafter, when the piston 36 moves toward the discharge chamber 66, the refrigerant and lubricating oil sucked into the compression chamber 58 are compressed, and when the compression pressure exceeds the shutoff pressure of the discharge valve 68, the discharge valve 68. Is opened. As a result, the compressed refrigerant containing the lubricating oil is discharged from the compression chamber 58 toward the discharge chamber 66 through the discharge port 60.

  The refrigerant containing the discharged lubricating oil flows along the annular surface of the discharge chamber 66 formed on the outer peripheral side of the suction chamber 70. In this process, the lubricating oil in the compressed refrigerant is separated from the refrigerant by the collision with the uneven portion in the discharge chamber 66 and adheres to the outer peripheral surface of the discharge chamber 66. Thereafter, the compressed refrigerant is sent out from the discharge passage 84 toward the forward path of the refrigerant circulation path 4. That is, the delivered refrigerant is condensed in the condenser 6, and the refrigerant in a gas-liquid mixed state is supplied to the evaporator 10 through the expansion valve 8. The two-phase refrigerant is vaporized in the evaporator 10, and the air around the evaporator 10 is cooled by the heat of vaporization. Accordingly, the cooling air can be cooled by introducing such cooling air into the vehicle interior.

  On the other hand, the lubricating oil separated from the compressed refrigerant and adhering to the outer peripheral surface of the discharge chamber 66 reaches the vicinity of each bolt hole 94 along the outer peripheral surface, and is returned to the crank chamber 74 through the return gap 88. That is, the discharge chamber 66 and the crank chamber 74 are always in communication with each other through the return gap 88, and the internal pressure of the discharge chamber 66 is set higher than the pressure of the crank chamber 74. Therefore, the lubricating oil in the discharge chamber 66 is reliably returned toward the crank chamber 74 through the communication groove 90 and the communication hole 92 based on the pressure difference between the discharge chamber 66 and the crank chamber 74.

  As described above, according to the compressor 2 of the present embodiment, the crankcase 14 and the cylinder head 16 that close both ends of the cylinder block 12 are connected by the connecting bolt 18, and the discharge chamber is provided around the connecting bolt 18. A return gap 88 for returning the lubricating oil in the discharge chamber 66 from 66 to the crank chamber 74 is provided. In the annular discharge chamber 66, the lubricating oil is separated from the refrigerant, and this lubricating oil is returned from the discharge chamber 66 into the crank chamber 74 via the communication groove 90 and the communication pore 92, and thus reaches the discharge chamber 66. The lubricating oil thus delivered is not sent out from the discharge chamber 66 to the refrigerant circulation path 4, and this lubricating oil is reliably secured in the crank chamber 74.

Accordingly, the lubricating oil is stably supplied into the crank chamber 74, and the lubricating oil is further separated from the refrigerant even in the high speed rotation region of the compressor 2, and the lubricating oil can be reliably secured in the crank chamber 74. In addition to lubrication of the sliding surface and bearings in the compressor 2, the function as a seal for the sliding surface can be sufficiently exhibited. As a result, the life of the compressor 2 can be extended.
Further, since this lubricating oil is reliably returned to the crank chamber 74, it becomes difficult for the lubricating oil to circulate through the refrigerant circulation path 4, and the lubricating oil ratio (OCR) flowing into the refrigeration circuit is further suppressed. As a result, a decrease in cooling capacity is further prevented.

Furthermore, the amount of lubricating oil previously sealed in the crank chamber 74 is also reduced, which contributes to a reduction in the operating cost of the compressor 2.
Further, the return gap 88 is composed of the communication groove 90 provided in the rear gasket 54 and the communication pore 92 provided in the cylinder block 12 and the like on the outer peripheral side of the connection bolt 18. Lubricating oil can be returned to the crank chamber 74 without major changes. Thereby, the manufacturing cost of the compressor 2 is reduced. Further, since the connecting bolt 18 itself has an existing configuration, this point also contributes to a reduction in manufacturing cost of the compressor 2.

Further, the flow rate in the return gap 88 is set to a gas flow rate that is about 10 to 500 cc / min when the pressure difference between the discharge chamber 66 and the crank chamber 74 is about 5 to 30 kg / cm ² . This range has critical significance. That is, when the flow rate is not reached, the amount of lubricating oil necessary for the compressor 2 cannot be secured in the crank chamber 74. On the other hand, when this flow rate is exceeded, a large amount of lubricating oil is retained in the crank chamber 74, causing the overall temperature of the compressor to rise, and adversely affecting the performance of the compressor 2.

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 embodiment, the communication groove 90 is provided in the rear gasket 54, but the present invention is not necessarily limited to this form. As an example, the communication groove may be provided in the rear gasket 54 and the valve plate 56, or may be provided in the front gasket 52. Furthermore, in the type without the rear gasket 54, the communication groove may be provided only in the valve plate. Furthermore, the communication groove communicating with the discharge chamber 66 may be provided only in the cylinder head 16 without being provided in the rear gasket, valve plate, or front gasket.

The flow rate in the return gap 88 can be secured by the size of the return gap 88, but the flow rate can also be secured by the degree of connection between the crankcase 14 and the cylinder head 16 by the connecting bolt 18. is there.
In the present invention, the shape of the discharge chamber is not necessarily limited to the above-described ring shape as long as the discharge chamber has a function of separating the lubricating oil from the refrigerant.

  Furthermore, the present invention is only required to return the lubricating oil in the discharge chamber to the crank chamber via a gap disposed around the connecting means, and is not limited to the configuration of the connecting bolt 18 as in the above embodiment. Absent. For example, the crankcase and the cylinder block may use bolts inserted from the crankcase side, while the cylinder block and the cylinder head may be inserted from the cylinder head side and use bolts that penetrate the cylinder block. And the front-end | tip of the volt | bolt inserted from this cylinder head side may reach a crank chamber, and the clearance gap which returns the lubricating oil in a discharge chamber to a crank chamber around the said volt | bolt may be arrange | positioned. Also in this case, as described above, the lubricating oil that has reached the discharge chamber is not sent out to the refrigerant circulation path, and the lubricating oil can be reliably secured in the crank chamber.

  Furthermore, the present invention can be applied to a reciprocating compressor of a swing plate type in addition to the swash plate type.

1 is a longitudinal sectional view showing a reciprocating compressor according to an embodiment of the present invention. It is an expanded sectional view of the gap | interval of FIG. FIG. 2 is a front view of a gasket disposed on a surface of a valve plate on the cylinder head side in FIG. 1.

Explanation of symbols

2 Swash plate compressor (reciprocating compressor)
4 Refrigerant circulation path 12 Cylinder block 14 Crankcase 16 Cylinder head 18 Connection bolt (connection means)
54 Rear gasket (gasket)
56 Valve plate 66 Discharge chamber 70 Suction chamber 74 Crank chamber 88 Return gap (gap)
90 Communication groove (groove)
92 communicating pores

Claims (4)

A compressor that compresses the working fluid sucked from the refrigeration circuit through the suction chamber, changes the discharge capacity by adjusting the pressure of the working fluid containing lubricating oil in the crank chamber, and discharges the compressed working fluid to the discharge chamber. There,
A cylinder block;
A crankcase comprising the crank chamber and closing one end of the cylinder block;
The valve plate is sandwiched to close the other end of the cylinder block, the suction chamber is provided at the center thereof, and formed on the outer peripheral side of the suction chamber and has a function of separating lubricating oil from the working fluid. A cylinder head with a discharge chamber;
Connecting means for connecting the cylinder block and the cylinder head through the cylinder block;
A reciprocating compressor characterized in that a gap for returning the lubricating oil in the discharge chamber from the discharge chamber toward the crank chamber is disposed around the connecting means. Between the other end of the cylinder block and the cylinder head, a gasket is disposed on the surface of the valve plate on the cylinder head side,
2. The reciprocating compressor according to claim 1, wherein the gap includes a groove disposed in the gasket and a fine hole disposed on an outer peripheral side of the connecting means.   The said connection means is inserted toward the said cylinder head from the said crankcase side, penetrates the said cylinder block, and connects the said crankcase and the said cylinder head. A reciprocating compressor. The flow rate in the gap is set to a gas flow rate of 10 to 500 cc / min when the pressure difference between the discharge chamber and the crank chamber is 5 to 30 kg / cm ^2. The reciprocating compressor according to any one of claims 3 to 4.

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