JP2008133815A - Swash plate of swash plate-type compressor, and swash plate-type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the friction wear characteristics of a sliding surface of a swash plate without lowering the efficiency of a compressor, and to enable the swash plate durable also in the swash plate-type compressor using carbon dioxide gas as coolant. <P>SOLUTION: On the sliding surface of the swash plate 3 on which a shoe slides, a spot-shaped or a streak-shaped recessed portion 12 is formed. Therefore, a plane surface portion of the sliding surface except for the recessed portion 12 is prevented from plastically deforming due to contact surface pressure with the shoe. Without lowering the efficiency of the compressor, lubricant oil is held in the recessed portion 23 to improve the friction wear characteristics of the sliding surface. Consequently, the swash plate is made to be durable also in the swash plate-type compressor using carbon dioxide gas as coolant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a swash plate compressor and a swash plate compressor used for an air conditioner or the like.

  In the housing where the refrigerant is present, the shoe is slid on the swash plate attached obliquely so as to be directly fixed to the rotating shaft or indirectly through the connecting member, and the swash plate rotates through this shoe. The swash plate compressor that compresses and expands the refrigerant into the reciprocating motion of the piston includes a double swash plate type that compresses and expands the refrigerant on both sides using a double-headed piston, and a single-headed piston. There is a swash plate type that compresses and expands the refrigerant only on one side. In addition, there are shoes that slide on only one side of the swash plate and those that slide on both sides of the swash plate.

  In these swash plate compressors, the metal swash plate and the shoe slide in the initial stage of operation before the lubricating oil reaches the housing in which the refrigerant exists. It becomes a state and seizure is likely to occur. In addition, in a swash plate type compressor that uses carbon dioxide gas as a refrigerant, which has been developed in recent years, the pressure in the compressor reaches 10 MPa, so the sliding pressure between the swash plate and the shoe is higher than before, and The sliding portion is more likely to be seized.

  As means for preventing this seizure, so far, a copper-based or aluminum-based metal material is sprayed on the sliding surface of the metal swash plate on which the shoe slides, and this metal sprayed layer is lead-plated, Tin-based plating, lead-tin-based plating, polytetrafluoroethylene (PTFE) -based coating, molybdenum disulfide coating or molybdenum disulfide-graphite mixed coating (for example, see Patent Document 1), and swash plate sliding A moving surface provided with a sliding layer obtained by solidifying a solid lubricant containing PTFE with a polyamide-imide resin (PAI) which is a thermosetting resin has been proposed (for example, see Patent Document 2). In addition, in order to improve the friction and wear characteristics in the boundary lubrication state including the dry lubrication state, a plurality of concentric grooves are provided on the sliding surface of the swash plate having the solid lubrication coating film, and adjacent grooves are provided. The thing which formed the mountain part is also proposed (for example, refer patent document 3).

Japanese Patent Laid-Open No. 8-199327 JP 2003-138287 A Republished Patent No. WO2002 / 075172

  In the method described in Patent Document 1, it is necessary to form a thermal spray layer of a copper-based material or an aluminum-based material on the surface of a metal base material, and to apply plating or coating treatment to the thermal sprayed layer. However, there is a problem that the manufacturing cost becomes expensive. In addition, although the manufacturing process of the swash plate does not increase so much in the one described in Patent Document 2, the PAI that forms the sliding layer uses carbon dioxide gas as a refrigerant only by adding a solid lubricant containing PTFE. The wear resistance that can be used for the swash plate compressor used cannot be secured.

  On the other hand, the one described in Patent Document 3 can improve the friction and wear characteristics of the sliding surface of the swash plate by holding the lubricating oil in the concentric circular groove. Since the shoe and the swash plate are arranged in series in the axial direction with a small dimensional tolerance of about 10 to 50 μm between them, the crests between the grooves are quickly plastically deformed by the contact surface pressure with the shoe. There is a problem in that the set dimensional tolerances are deviated and the piston motion becomes rattled and the like, causing a reduction in the efficiency of the compressor.

  Accordingly, an object of the present invention is to improve the friction and wear characteristics of the sliding surface of the swash plate without degrading the efficiency of the compressor, and to be able to withstand a swash plate type compressor using carbon dioxide as a refrigerant. It is.

  In order to solve the above-described problems, the present invention slidably slides a shoe on a swash plate attached obliquely so as to be directly fixed to a rotating shaft or indirectly through a connecting member in a housing in which a refrigerant exists. In the swash plate of the swash plate type compressor that compresses and expands the refrigerant by converting the rotational motion of the swash plate to the reciprocating motion of the piston through the shoe, the sliding surface of the swash plate on which the shoe slides In addition, a configuration in which a spot-like or streak-like recess was formed was adopted.

  That is, by forming a spot-like or streak-like recess on the sliding surface of the swash plate on which the shoe slides, the flat portion of the sliding surface excluding the recess is prevented from being plastically deformed by the contact surface pressure with the shoe. Thus, without causing a decrease in the efficiency of the compressor, the friction oil was retained in the recesses to improve the friction and wear characteristics of the sliding surface, so that it could be used in a swash plate compressor using carbon dioxide as a refrigerant.

When providing the recess spotted is preferably the area of the recess of the one and 3 mm ² to 20 mm ² approximately, the shape circular shape, elliptical shape, be of any shape such as a polygonal shape it can. Moreover, when providing a recessed part in a streak shape, it is preferable that the width | variety of each streaky recessed part shall be about 2 mm-5 mm, and the space | interval of these streaky recessed parts shall be about 3-10 mm. The concave portions may be arranged at random, or may be arranged in parallel linear, lattice, spiral, or radial alignment.

  The area of the flat surface portion of the sliding surface excluding the concave portion is 10 to 90%, preferably 50 to 90% of the entire sliding surface. If the area of the flat portion is less than 10%, the flat portion may be plastically deformed by the contact surface pressure with the shoe, and if it exceeds 90%, the amount of lubricating oil held in the recess is insufficient.

  The depth of the recess is preferably 20 to 50 μm. This is because if the depth is less than 20 μm, the lubricating oil retaining effect cannot be sufficiently expected, and if the depth exceeds 50 μm, it becomes difficult to process the recess.

  By forming the recess by compression molding, the recess can be easily formed in a short time. If the concave portions on the entire sliding surface are compressed and molded together with one pressing die, the concave portions can be easily formed in a shorter time.

  By forming the base material of the swash plate as a metal base material, forming a base layer in which metal powder is solidified on the sliding surface of the swash plate as the metal base material, and forming a resin coating layer on the base layer The adhesion of the resin coating layer can be ensured to improve the seizure resistance of the sliding surface.

  The base layer obtained by solidifying the metal powder can be formed by sintering, thermal spraying, or the like. The metal powder can be iron-based, copper-based, nickel-based, aluminum-based, or a composite of these. . In consideration of cost performance, nickel-based ones are preferable.

  The resin for forming the resin coating layer is not particularly limited as long as it has low friction characteristics, and is most preferably a fluororesin having excellent low friction characteristics and heat resistance sufficiently withstanding the use atmosphere of the swash plate. Specific examples include PTFE (melting point θM: 327 ° C., continuous use temperature θA: 260 ° C.). PTFE may be used singly or in combination of two or more types of copolymers or tricopolymers.

The PTFE is composed of repeating units of —CF ₂ CF ₂ —, has a high melt viscosity of about 10 ¹⁰ to 10 ¹¹ Pa · s even at about 340 to 380 ° C., and hardly flows even when the melting point is exceeded. Among them, heat resistance is most excellent, and excellent slidability and non-adhesiveness (contact angle with water: 104 °) are excellent even at room temperature. Furthermore, among PTFE, it is preferable to use a lubricant grade powder PTFE, and examples of commercially available lubricant grade powder PTFE include Polyflon M15, Lubron L-2 (trade name, manufactured by Daikin Industries), Teflon TLP-10 ( DuPont brand name), Fullon G163 (Asahi Glass brand name) and the like. Note that the lubricant-grade powder PTFE means regenerated PTFE obtained by pulverizing PTFE that has been fired once, PTFE powder that has been subjected to gamma ray irradiation treatment to reduce the molecular weight, and examples of commercially available products that have been subjected to gamma ray irradiation treatment include: KTL610 (trade name, manufactured by Kitamura Co., Ltd.)

  When a fluororesin is used for the resin coating layer, a polyimide resin, a polyamideimide resin, an epoxy resin, a phenol resin, or the like can be used as the binder resin. Among these, a polyamide-imide resin is preferable because it has excellent adhesion to the base layer and high heat resistance. The blending ratio of the binder resin in the resin coating layer is preferably 100 to 150 parts by weight of the binder resin with respect to 100 parts by weight of the fluororesin. This is because if the binder resin is less than 100 parts by weight, the adhesion of the resin coating layer is impaired, and if it exceeds 150 parts by weight, the sliding properties of the resin coating layer are impaired.

  In addition, as a method for forming the resin coating layer, various methods such as a dipping method, a spray coating method, a dispensing method, a roll method and the like can be adopted. In the spray coating method, the thickness of the resin coating layer is accurately determined. Can be well formed. The thickness of the resin coating layer is 5 to 50 μm, preferably 10 to 40 μm, after the firing. This is because if the layer thickness is less than 5 μm, it may be locally abraded when a piece hits the shoe or the like, and if the layer thickness exceeds 50 μm, the resin coating layer may be peeled off.

  The present invention also employs a configuration in which the swash plate compressor is provided with any of the swash plates described above.

  The swash plate compressor is suitable for those using carbon dioxide gas as a refrigerant.

  The swash plate of the swash plate compressor according to the present invention is formed by forming a spot-like or streak-like recess on the sliding surface of the swash plate on which the shoe slides, so that the flat portion of the sliding surface excluding the recess is in contact with the shoe. Swash plate compressor that uses carbon dioxide gas as refrigerant to maintain frictional oil in the recess and improve friction and wear characteristics of the sliding surface without reducing the efficiency of the compressor, because it does not cause plastic deformation due to contact surface pressure It can also be made to be durable.

  By forming the recess by compression molding, the recess can be easily formed in a short time. If the concave portions on the entire sliding surface are compressed and molded together with one pressing die, the concave portions can be easily formed in a shorter time.

  By forming the base material of the swash plate as a metal base material, forming a base layer in which metal powder is solidified on the sliding surface of the swash plate as the metal base material, and forming a resin coating layer on the base layer The adhesion of the resin coating layer can be ensured to improve the seizure resistance of the sliding surface.

  Further, since the swash plate compressor of the present invention is provided with the swash plate described above, even if it is used in a swash plate compressor that uses carbon dioxide gas as a refrigerant, the pressure in the compressor reaches 10 MPa, it can be sufficiently used. Can be.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This swash plate type compressor uses carbon dioxide gas as a refrigerant, and as shown in FIG. 1, a rotary motion of a swash plate 3 attached obliquely so as to be directly fixed to a rotary shaft 2 in a housing 1 where the refrigerant exists. Is converted into a reciprocating motion of a double-headed piston 5 through shoes 4 sliding on both side surfaces of the swash plate 3, and on both sides of each piston 5 in a cylinder bore 6 formed at equal intervals in the circumferential direction of the housing 1. The rotary shaft 2 that is a swash plate type that compresses and expands the refrigerant and is driven to rotate at high speed is supported by the needle roller bearing 7 in the radial direction and supported by the thrust needle roller bearing 8 in the thrust direction. Has been.

  Each piston 5 is formed with a recess 5a so as to straddle the outer periphery of the swash plate 3, and a hemispherical shoe 4 is seated on a spherical seat 9 formed on the axially opposed surface of the recess 5a. The shoe 4 is also spherical and supports the piston 5 so as to be movable relative to the rotation of the swash plate 3. Thereby, the conversion from the rotational movement of the swash plate 3 to the reciprocating movement of the piston 5 is performed smoothly.

  The base material 3a of the swash plate 3 is made of steel, and as shown in FIG. 2, the base layer 10 sprayed with Ni powder is formed on the sliding surfaces on both sides of the base material 3a on which the shoe 4 slides. A resin coating layer 11 in which PFE as a binder resin and graphite powder are blended with PTFE as a fluororesin is formed thereon. The underlayer 10 is a Ni sprayed layer formed to a thickness of 200 μm and turned to a thickness of 80 μm.

  The resin coating layer 11 is obtained by applying a coating agent prepared by dissolving PAI in a solvent and mixing and dissolving PTFE and graphite powder into the dissolved resin solution from above the underlayer 10 by a spray coating method. The blending ratio is such that the PAI is 150 parts by weight, the graphite powder is 10 parts by weight, and the thickness is 10 to 40 μm with respect to 100 parts by weight of PTFE. Here, PTFE was irradiated with recycled PTFE, PAI was PAI varnish dispersed with N-methylpyrrolidone, and graphite powder was artificial graphite having an average particle size of 10 μm.

  As shown in FIG. 3A, on the sliding surface of the swash plate 3, speckle-shaped concave portions 12 are arranged in a state of being aligned in parallel straight lines. Each recess 12 has an elliptical shape with a major axis of 3 mm and a minor axis of 2 mm, and its depth is 25 to 35 μm. These recesses 12 are compression molded together with a single die, and the recesses 12 formed by this compression molding are formed by compression molding before firing the coating film of the resin coating material provided on the swash plate substrate. And the resin coating layer is formed by baking a coating film after that. By carrying out like this, it can prevent that a crack etc. generate | occur | produce in a resin coating layer. Further, since the adhesion strength of the resin coating layer 11 is increased, the resin coating layer 11 can also be used in a swash plate type compressor using a carbon dioxide gas whose pressure in the compressor reaches 10 MPa as a refrigerant.

  3 (b) and 3 (c) show modifications of the formation pattern of the recesses 12, respectively. In the modified example of FIG. 3B, the spot-like concave portions 12 similar to those in FIG. 3A are arranged in a radially aligned state. In the modification of FIG. 3C, the streak-like recesses 12 are arranged in a grid pattern that intersects at right angles. The width of the grid-like streak-like recesses 12 is 2 mm to 5 mm, and the spacing between the grids is 3 to 3. 10 mm. The spot-like recesses 12 are not regularly arranged as shown in FIGS. 3A and 3B but may be randomly arranged without regularity. Further, the streak-shaped recess 12 may be crossed obliquely.

  As an example, the base layer 10 and the resin coating layer 11 of the stainless sprayed layer were formed on one side of a steel (S45C) disk (diameter 60 mm, thickness 6 mm) as described above, respectively, as shown in FIG. , (B), Test pieces (Examples 1 to 3) in which the recesses 12 were formed in the pattern shown in (c) were prepared. In any of the examples, the recess 12 is formed by compression molding before firing the coating film of the coating material, and then formed on the surface of the resin coating layer 11 by firing the coating film. Further, as a comparative example, a test piece (Comparative Example 1) in which the Ni sprayed base layer 10 and the resin coating layer 11 are formed and the recess 12 is not formed, and the Ni sprayed layer base layer 10 and the resin are formed. A test piece (Comparative Example 2) in which a coating layer 11 is formed and concentric grooves (depth 10 μm, pitch 0.5 mm) similar to Patent Document 3 are formed on the surface of the resin coating layer 11 by turning. Prepared.

A frictional wear test using a thrust type tester (3 shoe-on-type) that slides three steel shoes on each of the test pieces of the above examples and comparative examples was conducted. The friction coefficient of the sliding part and the wear amount of the test piece sliding surface after 10 minutes were measured. The test conditions are as follows.
・ Sliding surface pressure: 10MPa
・ Sliding speed: 200 m / min ・ Lubricating condition: State where the sliding surface is wetted with PAG refrigerating machine oil ・ Test time: 10 minutes

  Table 1 shows the results of the friction and wear test. In each of the examples in which the concave portion was formed on the sliding surface of the test piece, the friction coefficient from the initial test to 10 minutes later was stable, and the amount of wear on the sliding surface was very small. On the other hand, both the comparative example 1 in which the concave portion was not formed on the sliding surface and the comparative example 2 in which the concentric groove was formed on the sliding surface increased the friction coefficient after 10 minutes. However, the amount of wear on the sliding surface is also increasing. Especially the thing of the comparative example 1 has a large degree of these malfunctions. From the above results, the swash plate according to the present invention in which the swash plate or the streak-like concave portion is formed on the sliding surface has excellent friction and wear characteristics, and the swash plate compressor uses carbon dioxide gas whose pressure in the compressor reaches 10 MPa as the refrigerant. It has been found that even if it is used, it can be sufficiently used without causing a reduction in the efficiency of the compressor.

  In the above-described embodiment, the swash plate type swash plate compressor is configured such that the shoes slide on both sides of the swash plate. However, the swash plate of the swash plate compressor according to the present invention is of a swash plate type. In addition, the present invention can be applied to all types of swash plate compressors such as a shoe that slides only on one side of a swash plate, and a swash plate that is attached to a rotating shaft via a connecting member.

A longitudinal sectional view showing an embodiment of a swash plate compressor Sectional drawing which expands and shows the swash plate of FIG. a is a plan view showing a pattern of recesses formed on the sliding surface of the swash plate in FIG. 2, and b and c are plan views showing modified examples of the pattern of recesses in a, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Rotating shaft 3 Swash plate 4 Shoe 5 Piston 5a Recess 6 Cylinder bore 7 Needle roller bearing 8 Thrust needle roller bearing 9 Spherical seat 10 Underlayer 11 Resin coating layer 12 Recess

Claims (8)

  In the housing where the refrigerant is present, the shoe is slid on the swash plate attached obliquely so as to be directly fixed to the rotating shaft or indirectly through the connecting member, and the swash plate is rotated through this shoe. In a swash plate of a swash plate compressor that converts the movement into a reciprocating motion of the piston to compress and expand the refrigerant, a spot-like or streak-like recess is formed on the sliding surface of the swash plate on which the shoe slides. A swash plate for swash plate compressors.   The swash plate for a swash plate compressor according to claim 1, wherein the area of the flat portion of the sliding surface excluding the concave portion is 10 to 90% of the entire sliding surface.   The swash plate of the swash plate type compressor according to claim 1 or 2, wherein the depth of the recess is 20 to 50 µm.   The swash plate of a swash plate compressor according to any one of claims 1 to 3, wherein the concave portions are arranged in a state of being aligned in a parallel linear shape, a lattice shape, a spiral shape, or a radial shape.   The swash plate of the swash plate type compressor according to any one of claims 1 to 4, wherein the concave portion is formed by compression molding.   A swash plate compressor comprising the swash plate according to any one of claims 1 to 5.   The swash plate compressor according to claim 6, wherein the swash plate compressor uses carbon dioxide as a refrigerant. In the housing where the refrigerant is present, the shoe is slid on the swash plate attached obliquely so as to be directly fixed to the rotating shaft or indirectly through the connecting member, and the swash plate is rotated through this shoe. In the method of manufacturing a swash plate for a swash plate compressor that converts the motion into a reciprocating motion of the piston to compress and expand the refrigerant,
A sliding surface on which the shoe of the base plate of the swash plate slides is coated with a coating film of a resin coating agent, and a spot-like or streaky recess is formed on the surface of the coating film by compression molding before baking the coating film. And then forming a resin coating layer by firing the coating film. A method for producing a swash plate for a swash plate compressor.

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