JP2009191819A - Swash plate type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a swash plate type compressor improved in durability and reliability on a compressor by forcibly supplying a lubricant to a thrust bearing and a shaft seal part or the like, and improved in COP (coefficient of performance) by improving heat exchanging efficiency. <P>SOLUTION: This swash plate type compressor has a piston comprising a piston head inserted into a cylinder bore of a housing freely to reciprocate and a piston neck having front and rear shoe seats, in which a pair of front and rear shoes for pinching a swash plate arranged in a crank chamber freely to be integrally rotated with a rotary shaft are incorporated. The piston neck is protruded outwardly in the piston radial direction more than the peripheral surface of the piston head, and structured to form a space having a variable volume in cooperation with the inner surface of the housing at least when the piston is positioned near the top dead center. A lubricant circulation path for returning a lubricant existing in the space and fed from the space with a volume change of the space is made to communicate with the space. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a so-called single-head piston type swash plate compressor used in an air conditioner for automobiles, and more particularly to a lubricating oil circulation structure.

  As a so-called single-head piston type swash plate compressor used in an air conditioner for automobiles, for example, a compressor as shown in FIG. 3 is known (Patent Document 1). Since the basic structure of the conventional swash plate compressor shown in FIG. 3 and the swash plate compressor according to the present application shown in FIG. 1 are the same, the same members are denoted by the same reference numerals. In FIG. 3, reference numeral 100 denotes a swash plate compressor. The swash plate compressor 100 includes a housing 2 (cylinder block), a front housing 3 joined to one end of the housing 2, and a cylinder head 4 joined to the other end of the housing 2 via a seat plate 5. ing. A crank chamber 6 is formed between the housing 2 and the front housing 3. A rotating shaft 7 extends in the crank chamber 6, and the rotating shaft 7 is rotatably supported by bearings 8 and 9. A shaft seal 27 made of a mechanical seal is provided at one end of the rotary shaft 7 so that the inside of the compressor is sealed from the outside. The rotating shaft 7 is provided with a swash plate 10 and a rotor 11 that are provided in the crank chamber 6 and can rotate integrally with the rotating shaft 7. The rotor 11 is supported by a thrust bearing 12 provided on the inner wall of the front housing 3. In addition, an arm 14 having a guide hole 13 for the swash plate 10 extends from the periphery of the rotor 11. On one side surface of the swash plate 10, a connecting portion 15 is integrally provided. A spherical fitting portion 16 is provided at the tip of the connecting portion 15. By fitting the fitting portion 16 into the guide hole 13 of the arm 14, the torque of the rotating shaft 7 is transmitted to the swash plate 10 via the rotor 11, so that the swash plate 10 is rotated so that the tilt angle can be varied. It has become.

  The housing 2 is provided with a plurality of cylinder bores 17 in the circumferential direction. A piston 18 is provided in the cylinder bore 17 so as to be able to reciprocate. The piston 18 has a piston head portion 18 a fitted into the cylinder bore 17 and a piston neck portion 18 b having a seat portion 20 into which a pair of front and rear shoes 19 sandwiching the peripheral edge portion of the swash plate 10 is incorporated. The piston neck 18b protrudes outward in the piston radial direction from the peripheral surface of the piston head 18a. For this reason, when the piston 18 is in the vicinity of the top dead center, a space 21 in which the volume is changed by the cooperation of the piston neck 18b and the inner surface of the housing 2 is formed.

  The inside of the cylinder head 3 is divided into a suction chamber 23 and a discharge chamber 24 by an inner wall 22, and the suction chamber 23 is communicated with the cylinder bore 17 through a suction hole 25. Further, the discharge chamber 24 communicates with the cylinder bore 17 through the discharge hole 26.

  In such a swash plate compressor 100, when a driving force from a driving source (for example, a vehicle engine) is transmitted to the rotating shaft 7, the rotation of the swash plate 10 is converted into the reciprocating motion of the piston 18. It has become. Then, the fluid (for example, carbon dioxide refrigerant) flowing into the cylinder bore 17 from the suction chamber 23 through the suction hole 25 is compressed, and the compressed fluid is discharged into the discharge chamber 24 through the discharge hole 26. ing.

  Further, in such a compressor 100, the piston neck portion 18b of the piston 18 is in sliding contact with the concave portion 28 on the inner surface of the crank chamber 6 formed by the housings 2 and 3, so Even if a torque load from the swash plate 10 acts on the piston neck 18b as in the case of a plate compressor, the piston 18 is prevented from being tilted and worn or seized. In addition, in the swash plate type compressor before the proposal of Patent Document 1, the fitting length of the piston to the cylinder bore has been increased so as to resist the inclination of the piston.

However, in the swash plate compressor described in Patent Document 1, when the piston 18 is near top dead center, the space 21 formed by the piston neck 18b and the inner surface of the housing 2 is formed in a sealed space. When the piston 18 moves to the top dead center side, the fluid compression reaction force in the space 21 increases. Since the compression reaction force accompanying the compression of the fluid in the space 21 is added to the compression reaction force from the cylinder bore 17, the durability of the swash plate 10 and the thrust bearing 12 may be reduced. In particular, when an incompressible fluid such as lubricating oil is present in the fluid, excessive power loss may occur. Further, Patent Document 1 discloses a compressor that reduces the sliding surface to the inner surfaces of the housings 2 and 3 instead of circular in the cross-sectional shape of the piston neck portion 18b, reduces frictional resistance, and improves durability. However, since the oil supply function to the rotating shaft 7, the thrust bearing 12, and the shaft seal 27 cannot be provided, the durability of the apparatus may be adversely affected.
JP-A-11-294321

  The object of the present invention is to improve the durability and reliability of the compressor by forced lubrication of the lubricating oil to the thrust bearing and the shaft seal, and to improve the heat exchange efficiency, thereby reducing the COP (coefficient of performance). An object of the present invention is to provide a swash plate compressor that can be improved.

In order to solve the above-described problems, a swash plate compressor according to the present invention includes a piston head that is removably inserted into a cylinder bore of a housing, and a swash plate that is disposed in a crank chamber so as to be integrally rotatable with a rotary shaft. And a piston neck having front and rear shoe seats into which a pair of front and rear shoes to be sandwiched are incorporated, and the piston neck protrudes outward in the piston radial direction from the peripheral surface of the piston head In addition, in the swash plate compressor configured to form a space in which the volume can be changed in cooperation with the inner surface of the housing at least when the piston is in the vicinity of the top dead center, the volume of the space is set in the space. A lubricating oil circulation path for returning the lubricating oil present in the space sent out from the space with the change to the crank chamber is communicated. According to this structure, the lubricating oil interposed in the gap between the piston and the cylinder bore, said the pressure difference [Delta] P between the pressure P _c of the internal pressure P _d and the crank chamber of the discharge chamber (ΔP = P d _{-P c)} It flows into the space. When the volume of the space decreases due to the movement toward the top dead center side of the piston, the lubricating oil existing in the space flows in the order of, for example, the inlet side lubricating oil passage, the shaft lubricating oil passage, and the outlet lubricating oil passage. And flows into the crank chamber through the lubricating oil circulation path. The lubricating oil that has flowed into the crank chamber is drawn toward the piston head by reciprocation of the piston neck, and circulates again into the space. Therefore, the durability of the thrust bearing and the shaft seal portion and the durability of the compressor can be improved as a result. Normally, a large amount of lubricating oil is distributed near the wall surface of the crank chamber. However, in the swash plate compressor as described above, the lubricating oil with the wall surface of the crank chamber is actively taken in and the lubricating oil is effectively used. In addition, since each part is lubricated, efficient lubrication can be realized while reducing the amount of lubricating oil sealed in the compressor. As a result, the amount of lubricating oil flowing out to the refrigeration system can be reduced as a result, so that COP can be improved by improving heat exchange efficiency. In addition, the forced lubrication of the shaft seal portion improves the sliding state and durability of the relative sliding portion, particularly when the shaft seal portion is constituted by a mechanical seal, so that it is possible to reduce refrigerant gap leakage. .

  The housing is preferably formed with a recess that is slidably fitted to the piston neck. According to such a configuration, the inclination of the piston due to the torque load from the swash plate acting on the piston neck is prevented, and wear and seizure can be prevented.

  Preferably, the piston neck is provided with a seal member that slides on the inner surface of the housing. According to such a configuration, the amount of lubricating oil flowing directly into the crank chamber from the space can be reduced, so that the lubricating oil in the space can be efficiently introduced into the lubricating oil circulation path.

  The lubricating oil circulation path can be configured as a circulation path for circulating the lubricating oil fed from the space in one direction and returning it to the crank chamber.

  The lubricating oil circulation path includes at least an in-shaft lubricating oil passage that extends in the axial direction within the rotating shaft, and an inlet-side lubrication that is provided in the housing and communicates the space and the in-shaft lubricating oil passage. An oil passage, and an outlet-side lubricating oil passage that communicates the lubricating oil outlet of the in-shaft lubricating oil passage with the shaft seal portion and the bearing portion of the rotating shaft and communicates with the crank chamber. preferable. In particular, it is preferable that the outlet side lubricating oil passage is formed so as to pass through a thrust bearing portion which is disposed on the crank chamber inner surface and receives a compression reaction force of the piston.

  It is preferable that any part of the steam lubricating oil circulation path is provided with a backflow preventing means for preventing a backflow with respect to the unidirectional flow of the lubricating oil. For example, the backflow prevention means can be constituted by means having a weir structure, and the backflow prevention means having a weir structure is preferably provided on the inlet side of the in-shaft lubricating oil passage.

  The swash plate compressor according to the present invention is particularly suitable as a swash plate compressor using a carbon dioxide refrigerant operated in a high pressure state.

  According to the swash plate type compressor of the present invention, the lubricating oil that has flowed into the space formed between the piston neck and the inner wall of the housing is, for example, an inlet-side lubricating oil passage, an in-shaft lubricating oil as the piston moves. Since it is circulated into the space again through the lubricating oil circulation path that flows in the order of the passage and outlet lubricating oil passage, the durability and thus compression by forced oil supply to the thrust bearing and shaft seal part The durability of the machine can be improved. In addition, since the lubricating oil with the wall of the crank chamber is effectively used and used for lubrication of each part, efficient lubrication can be realized while reducing the amount of lubricating oil sealed in the compressor, and heat exchange efficiency is improved. COP can be improved. In addition, the forced lubrication of the shaft seal portion improves the sliding state and durability of the relative sliding portion, particularly when the shaft seal portion is constituted by a mechanical seal, so that it is possible to reduce refrigerant gap leakage. .

  Preferred embodiments of a swash plate compressor according to the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a swash plate compressor. The swash plate type compressor 1 in the following embodiment is configured as a swash plate type compressor of a refrigeration cycle of a vehicle air conditioner that uses carbon dioxide refrigerant as a fluid. Since the basic structure of the swash plate compressor is the same as that of the conventional compressor shown in FIG. 3, the same members are denoted by the same reference numerals and description thereof is omitted.

  The swash plate compressor 1 is formed with a space 21 in which the volume can be changed in cooperation with the inner surface of the housing 2 at least when the piston is in the vicinity of the top dead center. A lubricating oil circulation path 29 for returning the lubricating oil sent out from the space 21 to the crank chamber 6 is provided.

  The lubricating oil circulation path 29 is provided on the inlet side where the in-shaft lubricating oil passage 30 extending in the axial direction in the rotary shaft 7 and the space 21 provided in the housing 2 communicates with the in-shaft lubricating oil passage 29. The lubricating oil passage 31, the lubricating oil outlet of the in-shaft lubricating oil passage 30, and the outlet-side lubricating oil passage communicating with the shaft seal portion 27 of the rotating shaft 7, the bearing 8, and the thrust bearing 12 and into the crank chamber 6. 32.

  A seal member 33 that is in sliding contact with the inner surfaces of the housings 2 and 3 is provided on the piston neck 18 b of the piston 18. In addition, the housing 2 is provided with a recess 28 that fits in a slidable contact with the piston neck 18b.

In the present embodiment, the lubricating oil interposed in the gap between the piston 18 and the cylinder bore 17 is the pressure difference ΔP (ΔP = P _d −P _c ) between the internal pressure P _d of the discharge chamber 24 and the internal pressure P _c of the crank chamber 6. Flows into the space 21. When the volume of the space 21 decreases due to the movement toward the top dead center side of the piston 18, the lubricating oil existing in the space 21 flows into the inlet-side lubricating oil passage 31, the in-shaft lubricating oil passage 30, and the outlet lubricating oil passage 32. It flows into the crank chamber 6 through the lubricating oil circulation passage 29 that circulates in this order. The lubricating oil that has flowed into the crank chamber 6 is drawn toward the piston head 18a side by the reciprocating motion of the piston neck 18b, and circulates again into the space 21. Therefore, the forced lubrication to the bearing 8, the thrust bearing 12, and the shaft seal portion 27 can improve the durability of the bearing 8, and the durability of the compressor. Normally, a large amount of lubricating oil is distributed in the vicinity of the wall surface of the crank chamber 6, but in the swash plate compressor 1, the piston neck 18 b having the seal member 33 slidably in contact with the inner surfaces of the housings 2 and 3 reciprocates. Lubricating oil with the wall surface of the crank chamber 6 is actively taken in, and the lubricating oil is effectively utilized and used for lubrication of each part. Therefore, efficient lubrication is achieved while reducing the amount of lubricating oil sealed in the compressor. Can be realized. As a result, the amount of lubricating oil flowing out to the refrigeration system can be reduced as a result, so that COP can be improved by improving heat exchange efficiency. In addition, the forced lubrication of the shaft seal portion 27 improves the sliding state and durability of the relative sliding portion, particularly when the shaft seal portion 27 is constituted by a mechanical seal, so that the refrigerant gap leaks. Can be reduced.

  Further, as described above, the lubricating oil in the lubricating oil circulation path 29 is moved along with the reciprocating motion of the piston 18, so that the space 21, the inlet-side lubricating oil path 31, the in-shaft lubricating oil path 30, the outlet lubricating oil path 32, the crank chamber. 6. It is circulated only in one direction in the order of the flow path reaching the space 21 again.

  Further, since the housing 2 is formed with a recess 28 slidably fitted to the piston neck 18b, the piston 18 is prevented from tilting due to torque load from the swash plate 10 acting on the piston neck 18b. Prevents burn-in. Further, since the piston neck portion 18b is provided with the seal member 33 that slides on the inner surfaces of the housings 2 and 3, the amount of lubricating oil flowing directly into the crank chamber 6 from the space 21 can be reduced. The inside lubricating oil can be efficiently introduced into the lubricating oil circulation path 29 side.

  FIG. 2 shows the backflow prevention means 34 provided in the lubricating oil circulation path 29 of the swash plate compressor according to the second embodiment of the present invention. In addition, the same number is attached | subjected to the member same as the said 1st embodiment, and description is abbreviate | omitted. The backflow prevention means 34 is constituted by means having a weir structure 35, and the weir structure 35 is provided on the inlet side of the in-shaft lubricating oil passage 30.

  Also in this embodiment, swash plate durability and COP can be improved in accordance with the operation of the first embodiment. Further, in the present embodiment, the lubricating oil circulation passage 29 is provided with the backflow prevention means 34 having the weir structure 35, and the weir structure 35 is provided on the inlet side of the in-shaft lubricating oil passage 30. The backflow of the lubricating oil once flowing into the lubricating oil circulation path 29 can be reliably prevented.

  The swash plate compressor according to the present invention is particularly suitable for a swash plate compressor using a carbon dioxide refrigerant as a swash plate compressor of a refrigeration circuit of a vehicle air conditioner.

It is a longitudinal section of the swash plate type compressor concerning the 1st embodiment of the present invention. It is an expanded sectional view of the weir structure of the backflow prevention means provided in the lubricating oil circulation path of the swash plate type compressor which concerns on 2nd embodiment of this invention. It is a longitudinal cross-sectional view of the conventional swash plate type compressor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100 Swash plate type compressor 2 Housing 3 Front housing 4 Cylinder head 5 Seat plate 6 Crank chamber 7 Rotating shaft 8, 9 Bearing 10 Swash plate 11 Rotor 12 Thrust bearing 13 Guide hole 14 Arm 15 Connection part 16 Fitting part 17 Cylinder bore 18 Piston 18a Piston head 18b Piston neck 19 Pair of shoes 20 Seat 21 Space 22 Inner wall 23 Suction chamber 24 Discharge chamber 25 Suction hole 26 Discharge hole 27 Shaft seal portion 28 Recessed portion 29 Lubricating oil circulation path 30 In-axis lubricating oil passage 31 Inlet side lubricating oil passage 32 Outlet side lubricating oil passage 33 Seal member 34 Backflow prevention means 35 Weir structure

Claims (10)

  Piston head portion including a piston head portion that is removably fitted in a cylinder bore of the housing, and a front and rear shoe seat portion in which a pair of front and rear shoes that sandwich a swash plate that is disposed in the crank chamber so as to rotate integrally with the rotation shaft are incorporated. The piston neck extends outward in the piston radial direction from the circumferential surface of the piston head, and at least when the piston is near top dead center, In the swash plate type compressor configured to form a space that can change the volume in cooperation, the space exists in the space that is sent out from the space as the volume of the space changes. A swash plate compressor characterized in that a lubricating oil circulation path for returning the lubricating oil to the crank chamber is connected.   The swash plate compressor according to claim 1, wherein the housing is formed with a recess that is slidably fitted to the piston neck.   The swash plate compressor according to claim 1 or 2, wherein the piston neck includes a seal member that slides with an inner surface of the housing.   The slanting oil circulation path according to any one of claims 1 to 3, wherein the lubricating oil circulation path is configured as a lubricating oil circulation path that circulates the lubricating oil fed from the space in one direction and returns the lubricating oil to the crank chamber. Plate type compressor.   The lubricating oil circulation path includes at least an in-shaft lubricating oil passage extending in the axial direction in the rotating shaft, and an inlet-side lubrication provided in the housing for communicating the space and the in-shaft lubricating oil passage. An oil passage, and an outlet-side lubricating oil passage that communicates a lubricating oil outlet of the in-shaft lubricating oil passage with a shaft seal portion and a bearing portion of the rotating shaft and communicates with the crank chamber. Item 5. A swash plate compressor according to any one of Items 1 to 4.   The swash plate compressor according to claim 5, wherein the outlet side lubricating oil passage is formed to pass through a thrust bearing portion that is disposed on a crank chamber inner surface and receives a compression reaction force of a piston.   The swash plate compressor according to any one of claims 4 to 6, wherein a backflow prevention means for preventing a backflow with respect to a one-way flow of the lubricating oil is provided at any part of the lubricating oil circulation path.   The swash plate compressor according to claim 7, wherein the backflow prevention means comprises means having a weir structure.   The swash plate compressor according to claim 8, wherein the backflow preventing means having the weir structure is provided on an inlet side of the in-shaft lubricating oil passage. The swash plate type compressor according to any one of claims 1 to 9, wherein a carbon dioxide refrigerant is used as the compressed fluid.

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