JP2012112291A - Swash plate compressor and surface treatment method for swash plate in swash plate compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swash plate compressor improved in abrasion resistance and slidability of a swash plate and shoes, and a surface treatment method for the swash plate in the swash plate compressor.SOLUTION: A variable-capacity swash plate compressor comprises: a shaft passing through a crank chamber and rotatably supported at a housing; a swash plate 22 that includes an opening through which the shaft is inserted, is disposed in the crank chamber and rotates synchronously with rotation of the shaft; pistons, each held at a circumferential edge of the swash plate 22, which slides reciprocally in a cylinder bore as the swash plate 22 rotates; and shoes 24, disposed between two side surfaces of the swash plate 22 and an engaging portion of the piston, which slide in contact with both the swash plate 22 and the piston. The swash plate 22 is constituted of an iron-based material. The sliding contact surfaces 34 of the swash plate 22 against the shoes 24 undergo a gas soft-nitriding process, a removal process executed after the soft-nitriding process in order to remove a nitride-containing compound layer while retaining a formed hardened layer 36, and a coating process 37 executed after the removal process to form a coating constituted of a solid lubricant.

Description

  The present invention relates to a swash plate compressor that includes a piston that reciprocates by rotation of a swash plate and a shoe that is in sliding contact with both of the swash plate. The present invention relates to a surface treatment method for a swash plate of a compressor and a swash plate type compressor.

  For example, a swash plate compressor widely used as a refrigerant compressor for a vehicle air conditioner includes (a) a shaft that passes through a crank chamber and is rotatably supported by a housing, and (b) the shaft is inserted. A swash plate disposed in the crank chamber and rotating in synchronism with the rotation of the shaft; and (c) a swash plate which is moored at the periphery of the swash plate, and is attached to the housing as the swash plate rotates. A piston that reciprocally slides in the formed cylinder bore; and (d) a shoe that is disposed between both side surfaces of the swash plate and the engaging portion of the piston, and is in sliding contact with both the swash plate and the piston. It is comprised including.

  Such a swash plate compressor is required to have good sliding characteristics between the swash plate and the shoe because the swash plate is rotated at high speed and highly loaded. That is, it is required to be excellent in various properties such as lubricity for smoothing the sliding contact between them, wear resistance that they are not easily worn, and seizure resistance that they are not easily seized. For this reason, a curing process is performed on both sliding contact surfaces, and a coating treatment for forming a solid lubricant coating is performed on one of the sliding contact surfaces.

As the swash plate hardening process, a quenching process is conceivable, but the swash plate may be distorted because the quenching temperature becomes high.
Therefore, soft nitriding treatment that can be cured at a temperature lower than the quenching temperature is performed. Specifically, the rotating member is fixed to the rotating shaft and rotates integrally with the rotating shaft, and the rotating shaft. And a swash plate that is connected to the rotating member via a link mechanism and rotates integrally with the rotation of the rotating member, and a shoe that relatively rotates on the sliding surface of the swash plate. And a piston that linearly reciprocates in the cylinder bore as the swash plate rotates, and the swash plate is provided with a convex portion that constitutes a part of the link mechanism. In the plate compressor, there is known a variable capacity swash plate compressor in which the swash plate and the convex portion are subjected to a surface treatment by a gas oxynitriding method or an electroless nickel-phosphorus-boron plating method ( See Patent Document 1 .

  Further, as a specific example of the film treatment for forming a film of solid lubricant, a rotating shaft, a swash plate supported by being inclined with respect to the rotating shaft, and the rotating shaft are supported so as to be rotatable but not movable in the axial direction. And a housing provided with a cylinder bore formed substantially parallel to the rotation shaft at a position eccentric from the rotation shaft, and an engagement straddling the outer periphery of the swash plate and a head slidably fitted in the cylinder bore A piston that is reciprocated by the rotation of the swash plate, and is disposed between both side surfaces of the swash plate and the engaging portion of the piston, and slides between both the swash plate and the piston. A swash plate compressor including a shoe in contact with the swash plate, wherein the swash plate is made of an iron-based material, and a lubricating coating is formed on at least a sliding contact surface in sliding contact with the shoe. Some are Of a material system, and at least the swash plate and the swash plate type compressor is a sliding contact nitriding shoe nitrocarburizing treatment is performed on the swash-plate-side sliding contact surface is known (see Patent Document 2).

JP-A-10-196531 JP 2003-42061 A

  However, in the variable capacity swash plate compressor described in Patent Document 1, when the nitriding treatment is performed, a nitride compound layer is formed on the sliding contact surface of the swash plate, so that the sliding contact surface of the swash plate rather than the shoe. There is a risk that the hardness of the shoe increases and the shoe is damaged by sliding. Further, when the sliding surface of the swash plate whose hardness is increased by nitriding is finished with a lathe, there is a disadvantage that the tool life is shortened.

  Further, the swash plate of the variable capacity swash plate compressor described in Patent Document 2 has a lubricating coating formed on the sliding contact surface. However, a dent is generated by scraping the lubricating coating at the sliding contact portion with the shoe. If sliding continues in such a dent state, both the swash plate and the shoe are damaged, resulting in the disadvantage of hindering smooth sliding.

  More specifically, the surface of the shoe is assembled in a mirror state with almost no fine irregularities, while the surface of the swash plate is assembled in a rougher state than the surface of the shoe. If the hardness of the swash plate is higher than that of the shoe in addition to the surface condition of both, the swash plate will damage the surface of the shoe, and if the sliding continues further, the surface of the damaged shoe will be inclined. The lubricating film is peeled off by damaging the plate, the slidability is deteriorated, and wear of both proceeds.

  The present invention has been made in view of the above problems, and in the swash plate compressor, the swash plate compressor and the swash plate compressor have improved wear resistance and slidability of the swash plate and the shoe. The main object is to provide a surface treatment method for a plate.

  The swash plate compressor according to the present invention includes a shaft that passes through a crank chamber and is rotatably supported by a housing, an opening through which the shaft is inserted, and is disposed in the crank chamber to synchronize with the rotation of the shaft. A rotating swash plate, a piston moored at the periphery of the swash plate, and reciprocatingly sliding in a cylinder bore formed in the housing as the swash plate rotates, both side surfaces of the swash plate, and the piston In the swash plate type compressor, which is disposed between the engaging portions and includes a shoe that is in sliding contact with both the swash plate and the piston, the swash plate is made of an iron-based material, and the shoe of the swash plate The sliding contact surface is subjected to a finishing process, a gas soft nitriding process is applied as a hardening process after the finishing process, and a hardened layer formed by the soft nitriding process is left after the soft nitriding process. Removal process for removing the nitride layer is applied, the coating process for forming a film of the solid lubricant after the removal process is characterized in that applied.

  By removing the nitrided compound layer by removing the nitrided compound layer by leaving the hardened layer formed by nitriding treatment, it is possible to prevent the shoe from being damaged by removing the nitrided compound layer having higher hardness than the shoe, Moreover, sufficient hardness can be ensured by the remaining hardened layer, and abrasion resistance can be obtained. In addition, since the solid lubricant film is formed on the sliding contact surface, it is possible to improve the slidability of the swash plate and the shoe.

  Further, the shoe is subjected to a thermosetting treatment, and the hardness of the swash plate is lower than the hardness of the shoe by the removing treatment.

  By increasing the hardness of the shoe by the thermosetting process and making the hardness of the swash plate lower than that of the shoe by the removing process, it is possible to improve the wear resistance of the both without damaging the shoe.

  Furthermore, the removal process is preferably a shot peening process.

  When the solid lubricant enters the fine irregularities formed on the sliding contact surface of the swash plate by the shot peening process, it is possible to increase the adhesive force of the lubricating film by the anchor effect.

  Furthermore, the solid lubricant is preferably a fluororesin.

  Since the hardened layer formed on the sliding surface of the swash plate has a high affinity with the fluororesin, it is possible to improve both the lubrication effect and the hardness increasing effect. That is, when a part of the solid lubricant layer is peeled off, the hardened layer formed by the soft nitriding process is microscopically mixed with the lubricating layer. It is possible to prevent seizure of the swash plate and the shoe.

  A shaft that passes through the crank chamber and is rotatably supported by the housing; and a swash plate that has an opening through which the shaft is inserted and that is disposed in the crank chamber and rotates in synchronization with the rotation of the shaft. A piston moored to the periphery of the swash plate and reciprocatingly slides in a cylinder bore formed in the housing as the swash plate rotates, and between the side surfaces of the swash plate and the engaging portion of the piston. In the surface treatment method for a swash plate of a swash plate compressor, the swash plate having a shoe disposed in sliding contact with both the swash plate and the piston, wherein the swash plate is made of an iron-based material. The sliding contact surface with the shoe is formed by a finishing process, a soft nitriding process after the finishing process, and a soft nitriding process after the soft nitriding process. Sere The hardened layer by residual and step of performing removal processing of removing the nitride compound, it is desirable to have a step of applying a coating process for forming a film of the solid lubricant after the removal process.

  By performing the soft nitriding process after the finishing process, it is possible to process the swash plate with a low hardness, thereby improving the workability. Further, by performing the finishing process before the nitrocarburizing treatment, the nitriding treatment is not necessary, so that the manufacturing cost can be reduced.

  The removal process is preferably a shot peening process.

As described above, according to the present invention, after the soft nitriding treatment is performed on the sliding surface of the swash plate with the shoe, the removal treatment is performed to remove the nitride compound by leaving the hardened layer formed by the soft nitriding treatment, By performing a film treatment for forming a solid lubricant film after this removal treatment, it is possible to improve the wear resistance and slidability of the swash plate and the shoe, and to prevent seizure. Become.
Also, by increasing the hardness of the shoe by thermosetting and lowering the hardness of the swash plate below that of the shoe, the wear resistance of both can be improved without damaging the shoe, and the part replacement cycle is lengthened. It becomes possible.
Further, since the anchor effect can be obtained by the shot peening process, it is possible to prevent the self-lubricant from being peeled off.
Furthermore, by using a fluororesin as the self-lubricant, it is possible to improve both the lubrication and hardness increase effects by utilizing the high affinity between the cured layer of the nitride compound and the fluororesin. .
Further, by performing the nitrocarburizing process after the finishing process, the workability can be improved, and the replacement cost of the consumable parts can be lengthened, so that the production cost can be suppressed. Furthermore, it is possible to reduce the manufacturing cost because a treatment such as a nitriding treatment is not necessary.

FIG. 1 is a configuration diagram showing the configuration of a swash plate compressor. FIG. 2 is an enlarged view of the sliding surface of the swash plate with the shoe. FIG. 3 is a graph showing the hardness of the swash plate of the swash plate compressor. FIG. 4 is a flowchart showing the manufacturing process of the swash plate of the swash plate compressor.

  Hereinafter, a swash plate compressor of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, a variable capacity swash plate compressor 1 of the present invention includes a cylinder block 2 and a rear head 4 assembled on the rear side (right side in the figure) of the cylinder block 2 via a valve plate 3. And a front head 5 assembled so as to close the front side (the left side in the figure) of the cylinder block 2. The front head 5, cylinder block 2, valve plate 3, and rear head 4 are fastened in the axial direction by fastening bolts 6 and constitute a housing 7 for the entire compressor.

  A crank chamber 8 defined by the front head 5 and the cylinder block 2 accommodates a shaft 9 having one end protruding from the front head 5. A relay member 11 attached in the axial direction by a bolt 10 is fixed to a portion of the shaft 9 protruding from the front head 5. The relay member 11 is rotatably fitted to the end of the front head 5 on the relay member 11. A drive pulley 12 connected to the vehicle engine via a belt is fixed by means such as screwing. Further, one end of the shaft 9 is hermetically sealed with the front head 5 through a seal member 13 provided between the shaft 9 and is supported rotatably by a radial bearing 14. The other end of the shaft 9 is rotatably supported by a radial bearing 15 accommodated in the cylinder block 2.

  The cylinder block 2 is formed with a through hole 16 in which the radial bearing 15 is accommodated, and a plurality of cylinder bores 17 arranged at equal intervals on a circumference centered on the through hole 16. A piston 18 is inserted into the cylinder bore 17 so as to be slidable back and forth. The piston 18 is formed hollow by joining a head 18a inserted into the cylinder bore 17 and an engaging portion 18b protruding into the crank chamber in the axial direction.

  A thrust flange 19 that rotates integrally with the shaft 9 is fixed to the shaft 9 in the crank chamber 8. The thrust flange 19 is rotatably supported with respect to the front head 5 via a thrust bearing 20, and a swash plate 22 is connected to the thrust flange 19 via a link member 21. The swash plate 22 is attached so as to be tiltable about a hinge ball 23 provided on the shaft 9, and rotates integrally with the rotation of the thrust flange 19. And the swash plate 22 is moored by the engaging part 18b of the piston 18 via a pair of shoes 24 which the peripheral part was provided in the front and back.

  Accordingly, when the shaft 9 rotates, the swash plate 22 rotates along with this, and the rotational motion of the swash plate 22 is converted into the reciprocating linear motion of the piston 18 via the shoe 24, and the piston 18 and the valve plate in the cylinder bore. The volume of the compression chamber formed between the two is changed.

  The valve plate 3 is formed with suction holes 25 and discharge holes 26 corresponding to the respective cylinder bores 17, and the rear head 4 has a suction chamber 27 for storing the working fluid supplied to the compression chamber, and a compression chamber. And a discharge chamber 28 for storing the working fluid discharged from the exhaust gas. The suction chamber 27 is formed in the central portion of the rear head 4, communicates with a suction port 29 that communicates with the outlet side of the evaporator, and communicates with the compression chamber via the suction hole 25 of the valve plate 3. The discharge chamber 28 is continuously formed around the suction chamber 27 and communicates with a discharge port that leads to the inlet side of a condenser (not shown) and also communicates with the compression chamber via the discharge hole 26 of the valve plate 3. It is possible. Here, the suction hole 25 is opened and closed by a suction valve 30 provided on the front side end face of the valve plate 3, and the discharge hole 26 is opened and closed by a discharge valve 31 provided on the rear side end face of the valve plate 3. It has become.

  As shown in FIG. 2, the shoe 24 has a piston-side sliding contact surface 32 that forms a convex spherical surface and slidably contacts the piston 18, and a swash plate-side sliding contact surface 33 that forms a flat surface and contacts the swash plate 22. It is formed in a spherical crown shape. The pair of shoes 24 is slidably held on the concave spherical surface of the piston 18 on the piston-side sliding contact surface 32, and both sliding contacts that are both side surfaces of the outer peripheral portion of the swash plate 22 on the swash plate-side sliding contact surface 33. It contacts the surfaces 34 and 35 and clamps the disk part of the swash plate 22 from both sides.

  The shoe 24 is manufactured by forging a bearing steel such as SUJ2 to form a material, quenching it as a hardening process, and polishing the sliding surface. It has a hardness of about 850 Hv by quenching.

  The swash plate 22 has a hardened layer 36 formed on slidable contact surfaces 34, 35 with the shoe 24, which is a disc portion on both sides, and a lubricant film 37 of a self-lubricant is formed on the surface of the hardened layer 36. Yes. In FIG. 2, the thicknesses of the hardened layer 36 and the lubricating film 37 are exaggerated for easy understanding.

  The hardened layer 36 is composed of a diffusion layer from which the outermost nitride compound layer formed by gas soft nitriding is removed. Specifically, nitrogen atoms enter between the atoms of the metal crystal lattice and are dissolved. It is constituted by a layer or a layer in which a nitride of an additive element is dispersed and deposited on a matrix phase in which nitrogen is dissolved.

  In the gas soft nitriding treatment of the sliding surfaces 34 and 35, first, nitrogen gas is diffused in an ammonia gas atmosphere at about 500 to 600 ° C., and a nitride compound layer (about 0.01 mm) is formed on the outermost surface, and a hardened layer is formed on the lower portion thereof 36 is formed. Here, as shown in FIG. 3, the hardness of the nitride compound layer is about 1000 Hv, which is higher than the swash plate side sliding contact surface 33 of the shoe 24, and there is a possibility of damaging the swash plate side sliding contact surface 33 when performing high speed sliding. Therefore, the slidable contact surfaces 34 and 35 are formed so that only the nitride compound layer is removed and the hardened layer 36 of about 600 Hv immediately below the compound layer is exposed. Thereby, sufficient hardness (Hv550 or more) required for abrasion resistance is ensured, suppressing hardness lower than the swash plate side sliding contact surface 33 of the shoe 24.

  Further, the lubricating film 37 is preferably formed of a fluorine resin solid lubricant in order to increase the affinity with the cured layer 36. Examples of the fluorine resin include polytetrafluoroethylene (tetrafluorinated resin). , Abbreviation: PTFE), polychlorotrifluoroethylene (trifluorinated resin, abbreviation: PCTFE, CTFE), polyvinylidene fluoride (abbreviation: PVDF), polyvinyl fluoride (abbreviation: PVF), perfluoroalkoxy fluororesin (abbreviation: PFA) ), Tetrafluoroethylene / hexafluoropropylene copolymer (abbreviation: FEP), ethylene / tetrafluoroethylene copolymer (abbreviation: ETFE), ethylene / chlorotrifluoroethylene copolymer (abbreviation: ECTFE), etc. Is mentioned.

The swash plate 22 is formed by processing an iron-based casting material including the FCD 600, and is specifically manufactured by the process shown in FIG.
That is, after performing rough processing (S101) to bring the material closer to the final shape than the material of the swash plate 22 formed by casting, the sliding contact surfaces 34 and 35 with the shoe 24 are further turned by a lathe to further increase the dimensional accuracy. A finishing process (S102) is performed. Further, a gas soft nitriding process (S103) is performed as a curing process, and a shot peening process (S104) is performed as a removing process for removing the nitride compounds formed on the sliding contact surfaces 34 and 35 from the nitride compounds formed by the gas soft nitriding process. I do. Thereafter, a fluororesin coating process (S105) is performed as a film process for forming the lubricating film 37 on the sliding surfaces 34 and 35.

In addition, by performing the fluororesin coating process in step S105 after the shot peening process in step S104, the fluororesin enters the fine irregularities on the surface generated by the shot peening process, so that the cured layer 36 is smoothed and the lubricating film 37 is obtained. It is possible to obtain an anchor effect that increases the adhesion force between the lubricant film 37 and the lubricant film 37 from being peeled off.
Even when part of the lubricant film 37 is peeled off by sliding of the swash plate 22, since the affinity between the hardened layer 36 and the lubricant film 37 is high, the fluororesin that has entered the irregularities is microscopically observed. It is possible to improve both the lubrication effect and the hardness increase effect by being mixed in the hardened layer 36.

  In addition, by performing the finishing process in step S102 before the soft nitriding process in step S103, it is possible to reduce damage to the blade used in the lathe and lengthen the blade replacement cycle.

DESCRIPTION OF SYMBOLS 1 Swash plate type compressor 2 Cylinder block 7 Housing 8 Crank chamber 9 Shaft 17 Cylinder bore 18 Piston 22 Swash plate 24 Shoe 34, 35 Sliding contact surface (swash plate)
36 Hardened layer 37 Lubricating film

Claims (6)

A shaft that passes through the crank chamber and is rotatably supported by the housing, an swash plate that has an opening through which the shaft is inserted and that is disposed in the crank chamber and rotates in synchronization with the rotation of the shaft; A piston moored at the periphery of the swash plate and reciprocally slides in a cylinder bore formed in the housing as the swash plate rotates, and is arranged between both side surfaces of the swash plate and the engaging portion of the piston. A swash plate compressor including a shoe that is in sliding contact with both the swash plate and the piston;
The swash plate is made of an iron-based material,
The sliding surface of the swash plate with the shoe is subjected to a finishing process, a gas soft nitriding process is performed after the finishing process, and a hardened layer formed by the soft nitriding process after the soft nitriding process A swash plate compressor, wherein a removal process is performed to remove the nitride compound layer by remaining, and a film process for forming a film of a solid lubricant on the sliding contact surface is performed after the removal process. The shoe is subjected to a thermosetting treatment,
The swash plate compressor according to claim 1, wherein the hardness of the swash plate is lower than the hardness of the shoe by the removing process.   The swash plate compressor according to claim 1 or 2, wherein the removing process is a shot peening process.   The swash plate compressor according to any one of claims 1 to 3, wherein the solid lubricant is a fluororesin. A shaft that passes through the crank chamber and is rotatably supported by the housing, an swash plate that has an opening through which the shaft is inserted and that is disposed in the crank chamber and rotates in synchronization with the rotation of the shaft; A piston moored at the periphery of the swash plate and reciprocally slides in a cylinder bore formed in the housing as the swash plate rotates, and is arranged between both side surfaces of the swash plate and the engaging portion of the piston. In the surface treatment method for a swash plate of a swash plate compressor, the shoe having sliding contact with both the swash plate and the piston, the swash plate being made of an iron-based material,
The sliding contact surface of the swash plate with the shoe is subjected to a finishing process,
A step of applying a soft nitriding treatment after the finishing processing is performed;
A step of removing the nitrided compound by leaving the hardened layer formed by the soft nitriding treatment after the soft nitriding treatment is performed; and
A surface treatment method for a swash plate of a swash plate compressor, comprising: performing a film treatment for forming a solid lubricant film after the removing treatment.   6. The surface treatment method for a swash plate of a swash plate compressor according to claim 5, wherein the removing process is a shot peening process.

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