JP6313682B2 - Swash plate compressor hemispherical shoe and swash plate compressor - Google Patents

Description

  The present invention relates to a hemispherical shoe for converting a rotary motion of a swash plate into a reciprocating motion of a piston interposed between a swash plate and a piston in a swash plate type compressor used for an air conditioner for automobiles and the like.

  The swash plate compressor slides a hemispherical shoe on a swash plate mounted at a right angle and obliquely so as to be directly fixed to a rotating shaft or indirectly through a connecting member in a housing where refrigerant exists. The rotational movement of the swash plate is converted into the reciprocating movement of the piston through the shoe to compress and expand the refrigerant. Such swash plate compressors include a double swash plate type that compresses and expands refrigerant on both sides using a double-headed piston, and a single-slope that compresses and expands refrigerant only on one side using a single-headed piston. There is a board type. In addition, the hemispherical shoes include those that slide only on one side of the swash plate and those that slide on both sides of the swash plate. In these swash plate type compressors, sliding with a large relative speed of 20 m or more per second occurs on the sliding surface of the swash plate and the hemispheric shoe, and the hemispheric shoe is used in a very severe environment.

  As for lubrication, the lubricating oil is diluted while dissolved in the refrigerant, circulates in the housing, and is supplied to the sliding portion in the form of a mist. However, when the operation is resumed from the operation stop state, the lubricating oil is washed away by the liquefied refrigerant, and the sliding surface between the swash plate and the hemispherical shoe at the start of the operation becomes a dry lubricating state without the lubricating oil, There is a problem that seizure is likely to occur.

  As a means for preventing this seizure, for example, a polyether ether ketone (PEEK) resin film is directly formed on at least sliding surfaces of a swash plate and a hemispherical shoe by an electrostatic powder coating method (see Patent Document 1). There has been proposed a thermoplastic polyimide coating containing a solid lubricant formed by an electrostatic powder coating method (see Patent Document 2).

  Further, in order to ensure high slidability under high speed and high temperature conditions, a binder made of PEEK resin at at least one sliding contact portion of the swash plate, hemispherical shoe and piston, and a solid lubricant dispersed in the binder The thing which formed the sliding layer which becomes (refer patent document 3) is proposed.

JP 2002-180964 A JP 2003-049766 A JP 2002-039062 A

  In the prior art, in order to improve the lubrication characteristics of the swash plate and the hemispherical shoe, as described above, a method of forming the sliding surface of the swash plate and the hemispherical shoe with a lubricating coating has been proposed. There was no formation of a lubricious coating on the hemispherical shoe, even though a lubricious coating was formed on the plate. The reason for this is that the sliding area of the hemispherical shoe is smaller than that of the swash plate, and the sliding with the spherical seat of the piston is also received. Is guessed.

  For example, when the entire surface of the hemispherical shoe is covered with a resin film for sliding with the swash plate and the piston as in the prior art, the heat dissipation of the frictional heat decreases and the temperature of the hemispherical shoe base material increases, It can happen that the resin coating dissolves. In addition, the formation of a resin film by electrostatic powder coating or coating liquid application exposes the hemispherical shoe to the firing temperature, and there is a concern that the strength may decrease. In addition, when a resin film is formed for each of the plurality of sliding surfaces of the hemispherical shoe, there is a possibility that peeling for each sliding surface is likely to occur structurally.

  On the other hand, a swash plate with a lubricious coating is not only strict in terms of flatness, parallelism and thickness accuracy of the sliding surface, but also has a low coating cost due to the large coating area of the lubricious coating made of expensive materials. There is a problem that you can not.

  The present invention has been made to address these problems, and seizure does not occur even in a dry lubrication state where there is no lubricating oil at the start of operation. It is an object to provide a hemispherical shoe with no durability and sufficient durability. Another object of the present invention is to provide a swash plate compressor in which a lubricating coating is removed from a sliding surface of a swash plate or a piston by using this hemispherical shoe.

  The hemispherical shoe of the swash plate compressor according to the present invention has a hemispherical shoe attached to a swash plate mounted at a right angle and obliquely so as to be fixed directly to a rotating shaft or indirectly through a connecting member in a housing in which a refrigerant exists. A swash plate-type compressor hemisphere shoe that slides and converts the rotational movement of the swash plate into a reciprocating movement of the piston through the hemisphere shoe to compress and expand the refrigerant. And having a resin layer on the surface of the flat part sliding with the swash plate and the surface of the spherical part sliding with the piston, the resin layer of the flat part and the resin layer of the spherical part, respectively. The resin layer having a thickness of 0.1 to 0.7 mm, and the resin layer having the flat surface portion and the resin layer having the spherical surface portion are made of an aromatic polyetherketone (aromatic PEK) resin as a base resin. Use above substrate Characterized in that it is formed integrally by injection molding to the surface.

  The metal member is a member made of iron-based sintered metal, and the density is a theoretical density ratio of the material of 0.7 to 0.9.

  The resin composition includes 1 to 30% by volume of a polytetrafluoroethylene (PTFE) resin and 5 to 30% by volume of at least one of carbon fiber and graphite, respectively, based on the entire resin composition. To do.

The melt viscosity at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ of the resin composition is 50 to 200 Pa · s.

  The swash plate type compressor of the present invention slides a hemispherical shoe on a swash plate attached at right angles and obliquely so as to be fixed directly to a rotating shaft or indirectly through a connecting member in a housing in which refrigerant exists. A swash plate compressor that compresses and expands the refrigerant by converting the rotational movement of the swash plate into a reciprocating movement of the piston through the hemispheric shoe, and the hemispheric shoe is the hemispheric shoe of the present invention. To do. The sliding surface of the swash plate with the hemispherical shoe is a polished surface of the swash plate base material and does not have a lubricating coating. Further, the refrigerant is carbon dioxide gas.

  The hemispherical shoe of the swash plate compressor of the present invention has a metal member as a base material, and a resin layer is formed with a thin insert at least on the surface of the flat part sliding with the swash plate and the surface of the spherical part sliding with the piston. Therefore, it is excellent in load resistance and excellent in slidability between both the swash plate and the piston. In addition, since the base resin of the resin composition forming the resin layer is an aromatic PEK-based resin, it is excellent in friction and wear characteristics, seizure resistance, various chemical resistances, and oil resistance. Furthermore, since pressure is applied in a molten state to the resin composition during injection molding, the resin layer is densely formed and excellent in load resistance and the like.

  Moreover, since the thickness of the resin layer is as thin as 0.1 to 0.7 mm, the frictional heat easily escapes from the friction surface to the base material side, and it is difficult to store heat. Furthermore, since the resin layer of the plane portion and the resin layer of the spherical portion are formed integrally by injection molding, it is possible to prevent the resin layer from being peeled off from the base material.

By setting the melt viscosity at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ to 50 to 200 Pa · s, the resin composition is excellent in thin insert moldability.

  Since the metal member is a member made of iron-based sintered metal, the surface area of the resin layer forming surface is large, and the anchor effect due to the unevenness is high, so that the adhesion strength with the resin layer is increased. In particular, at the time of injection molding of the resin layer (at the time of insert molding), the resin layer deeply digs into the irregularities on the surface of the sintered metal and the true bonding area increases, so that the adhesion strength between the resin layer and the substrate is improved. Furthermore, since the true bonding area between the resin layer and the base material is increased and there is no gap between the resin layer and the base material, the heat of the resin layer is easily transmitted to the base material. In addition, by setting the density of the iron-based sintered metal to the theoretical density ratio of the material of 0.7 to 0.9, while ensuring the surface irregularities for obtaining adhesion, the required denseness is obtained. The thermal conductivity of the substrate can also be secured. Moreover, since required joining strength is obtained in the junction part of a resin layer and a base material, even if it uses on high PV conditions, it can prevent that a resin layer peels from a base material.

  Since the resin composition contains 1 to 30% by volume of PTFE resin and 5 to 30% by volume of at least one of carbon fiber and graphite with respect to the entire resin composition, the resin layer even under high PV conditions. Deformation and wear can be prevented, damage to the swash plate and piston, which is the counterpart material, is small, resistance to oil is high, and seizure does not occur even in a dry state without lubricating oil during operation.

  Since the swash plate compressor of the present invention includes the above-described hemispherical shoe, no seizure occurs on the sliding surface of the hemispherical shoe even in a dry lubrication state without lubricating oil at the start of operation. This is a swash plate compressor that has excellent durability, no deterioration of lubrication characteristics due to heat generation, and no peeling of the resin layer. Also, using the above-described hemispherical shoe, the sliding surface of the swash plate with the hemispherical shoe is a polished surface of the swash plate base material and does not have a lubricous coating, so despite being functionally equivalent, A low-priced swash plate compressor can be provided. Furthermore, since it can be used for high surface pressure (for example, more than 8 MPa) specifications, it is suitable for those using carbon dioxide gas or HFC1234yf as a refrigerant.

It is a longitudinal cross-sectional view which shows an example of the swash plate type compressor of this invention. It is the longitudinal cross-sectional view and top view which expand and show the hemispherical shoe of FIG. It is a longitudinal cross-sectional view which shows the other example of a hemispherical shoe. It is a longitudinal cross-sectional view which shows the other example of a hemispherical shoe.

  An embodiment of a swash plate compressor according to the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an example of a swash plate compressor of the present invention. The swash plate type compressor shown in FIG. 1 uses carbon dioxide gas as a refrigerant. The swash plate 3 attached obliquely so as to be directly fixed to the rotary shaft 2 in the housing 1 in which the refrigerant exists is inclined. It is converted into a reciprocating motion of a double-headed piston 9 through a hemispherical shoe 4 that slides on both sides of the plate 3, and a refrigerant is generated on both sides of each piston 9 in a cylinder bore 10 formed at equal intervals in the circumferential direction of the housing 1. The swash plate type that compresses and expands. The rotary shaft 2 that is rotationally driven at high speed is supported by a needle roller bearing 11 in the radial direction and supported by a thrust needle roller bearing 12 in the thrust direction. In this configuration, the swash plate 3 may be fixed to the rotary shaft 2 indirectly via a connecting member. Moreover, the aspect attached rather than diagonally may be sufficient.

  Each piston 9 is formed with a recess 9 a so as to straddle the outer periphery of the swash plate 3, and a hemispherical shoe 4 is seated on a spherical seat 13 formed on the axially opposed surface of this recess 9 a, The swash plate 3 is supported so as to be movable relative to the rotation of the swash plate 3. Thereby, conversion from the rotational movement of the swash plate 3 to the reciprocating movement of the piston 9 is performed smoothly. The hemispherical shoe 4 has a spherical portion that slides with the piston 9 (spherical seat 13) and a flat portion that slides with the swash plate 3.

  The structure of the hemispherical shoe will be described in detail with reference to FIG. 2 is a longitudinal sectional view showing an example of the hemispherical shoe of the present invention, and the lower view of FIG. 2 is a plan view thereof. As shown in FIG. 2, the hemispherical shoe 4 includes a spherical portion 4a constituting a part of the sphere, a flat portion 4b in which the sphere is cut in a substantially flat surface on the opposite side of the spherical portion 4a, a spherical portion 4a, It has a substantially hemispherical structure composed of an outer peripheral part 4c connecting the flat part 4b. Further, the hemispherical shoe 4 has a circular planar shape, and the surface of the outer peripheral portion 4c (the surface of the resin layer 6c) is a cylindrical outer peripheral surface. The overall shape of the hemispherical shoe 4 is a shape in which one bottom surface of the cylindrical body is a convex shape constituting a part of the hemisphere. The overall shape of the hemispherical shoe 4 is not limited to this, and it is sufficient if it has a flat surface portion that slides with the swash plate and a spherical surface portion that slides with the piston. It is good also as a shape which does not have.

  The hemispherical shoe 4 has a metal member as a base material 5 and a resin layer 6 is formed by injection molding on the surface of a flat surface portion 4b that slides with a swash plate and the surface of a spherical surface portion 4a that slides with a piston. Of the resin layer 6, the resin layer 6a is formed on the surface of the spherical surface portion 4a, the resin layer 6b is formed on the surface of the flat surface portion 4b, and the resin layer 6 is formed on the outer peripheral portion 4c. Layer 6c. Each resin layer is thin, and the shape of the base material 5 is a shape along the entire shape of the hemispherical shoe 4. The diameter of the hemispherical shoe is about 10 mm (5 to 15 mm).

  The hemispherical shoe has an exposed portion that is not covered with a resin layer in other parts of the metal base material while forming the resin layer directly on the sliding surface of the piston and the swash plate. It is preferable to have. By providing the exposed portion, even if frictional heat due to sliding with the swash plate and the piston is generated, the heat can be transferred from the exposed portion through the base material, and the resin layer does not melt and the like. Excellent wear and seizure resistance.

  In the form shown in FIG. 2, the base material 5 is formed with a cylindrical space-like hollow portion 7 penetrating the spherical surface portion 4a side and the flat surface portion 4b side at the center axis portion of the circular center. The hollow portion 7 is filled with the resin layer 6d from the plane portion 4b side to a predetermined axial depth, and the other portion (exposed portion) is not covered with the resin, and the surface of the base material constituting the hollow portion is exposed. It has become a state. By having the exposed portion in the hollow portion 7, the frictional heat is radiated from the portion to the outside. The exposed portion also functions as an oil pocket that holds the lubricating oil. Further, the hemispherical shoe 4 having the form shown in FIG. 2 has a non-contact portion 8 with the piston on the outer surface on the spherical surface portion 4 a side, and the base material 5 is not covered with the resin layer 6 in the non-contact portion 8 and exposed. doing. The non-contact portion 8 is a portion having a shape obtained by cutting a part of the spherical portion 4a with a plane parallel to the flat portion 4b, and is a portion that does not slide contact with the piston. By providing such a non-contact part and an exposed part of the base material on the outer surface on the spherical part 4a side, it becomes easy to radiate the frictional heat generated in the spherical part from the exposed part.

  Another embodiment of the hemispherical shoe of the present invention will be described with reference to FIGS. 3 and 4 are longitudinal sectional views showing other examples of hemispherical shoes. In the hemispherical shoe 4 of FIG. 3, a hollow portion 7 that penetrates the spherical surface portion 4 a side and the flat surface portion 4 b side is formed in the central axis portion of the circular center of the base material 5. In this embodiment, the hollow portion 7 is filled with the resin layer 6d from the spherical surface portion 4a side to a predetermined axial depth, and the other portion (exposed portion) is not covered with the resin and is a base constituting the hollow portion. The material surface is exposed. Since the exposed portion of the hollow portion 7 is on the side of the flat portion 4b, the sliding property with the swash plate is particularly excellent due to the heat dissipation and the function as an oil pocket.

  The hemispherical shoe 4 in FIG. 4 is in an exposed state where the outer peripheral portion 4 c that connects the flat portion 4 b and the spherical portion 4 a is not covered with the resin layer 6. Since the outer peripheral part 4c is a part which does not slide with other members, such as a swash plate and a piston, formation of a resin layer is not essential. For this reason, compared with the spherical surface part 4a, the plane part 4b, and the hollow part 7 (FIG. 2, 3), it is easy to ensure the base-material exposed area used as a thermal radiation part large.

  2 to 4, the hemispherical shoe 4 is formed by directly injection-molding a thin resin layer 6 on the surface of the base material 5 using a resin composition containing an aromatic PEK-based resin as a base resin. Formed. Specifically, insert molding is performed in which the base material 5 is set in a mold and the resin is injection molded from above. During insert molding, the resin layer 6b of the flat surface portion 4b and the resin layer 6a of the spherical surface portion 4a include the outer peripheral portion 4c (FIGS. 2 and 3) and the resin layer of the hollow portion (FIG. 4) serving as a connecting portion. Are integrally formed. In the hemispherical shoe 4, the flat surface portion 4b that slides with the swash plate and the spherical surface portion 4a that slides with the piston are located on the opposite sides in the axial direction. By making the resin layers formed on these surfaces continuous and integrated through the outer peripheral portion and the hollow portion, the resin layers on both surfaces are structurally difficult to peel from the substrate.

  The thickness of the resin layer 6a and the resin layer 6b of the hemispherical shoe 4 is 0.1 to 0.7 mm, either an insert molding surface (one insert molding) or a surface finished to a required thickness by machining after molding. Good. In addition, the “thickness of the resin layer” in the present invention is the thickness of the surface portion that does not enter the substrate. Further, the thickness of the resin layer 6c of the outer peripheral portion 4c is preferably within this range. When the thickness of the resin layer exceeds 0.7 mm, the frictional heat hardly escapes from the friction surface to the substrate side, and the temperature of the friction surface increases. In addition, the amount of deformation due to the load increases, the real contact area on the friction surface also increases, the frictional force and frictional heat increase, and seizure resistance also decreases. On the other hand, when the thickness of the resin layer is less than 0.1 mm, the lifetime during long-term use is shortened.

In the case of one insert molding, considering the moldability, the thickness of each resin layer is preferably 0.2 to 0.7 mm. If the thickness of the resin layer is less than 0.2 mm, insert molding may be difficult. On the other hand, if it exceeds 0.7 mm, sink marks may occur and the dimensional accuracy may decrease. In consideration of the heat dissipation property of the frictional heat to the base material, the thickness of the resin layer is more preferably 0.2 to 0.5 mm. Also, in order to obtain a resin layer thickness of 0.2 to 0.5 mm by a single insert molding, the melt viscosity of the resin composition is 50 at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ as described later. It is preferable to be set to ~ 200 Pa · s.

  Within the above range, it is preferable that the thickness of the resin layer 6a of the spherical surface portion 4a is larger than the thickness of the resin layer 6b of the flat surface portion 4b. By making the resin layer of the spherical part thicker than the resin layer of the flat part, the resin part of the flat part that slides with the swash plate is thin, has high PV and high load resistance, and the spherical part that slides with the piston The resin layer is thick, has good conformability when per piece, and has excellent wear resistance. Furthermore, high melt fluidity at the time of injection molding can be secured.

  Examples of the metal member that is the base material 5 include members made of sintered metal such as iron, copper iron, copper, and stainless steel. Among these, a member made of an iron-based sintered metal is preferable because it is excellent in compressive strength and bonding strength with a resin and is low in cost. When a sintered metal is used as the metal material of the base material, the surface area of the resin layer forming surface is large and the anchor effect due to surface irregularities is high, so that the adhesion strength with the resin layer can be increased. Especially when the resin layer is formed by injection molding (insert molding), the resin layer digs deeply into the irregularities on the surface of the sintered metal, increasing the true bonding area, improving the adhesion strength between the resin layer and the substrate. To do. Furthermore, since the true bonding area between the resin layer and the base material is increased and there is no gap between the resin layer and the base material, the heat of the resin layer is easily transmitted to the base material.

  When a base material is inserted into the mold and the aromatic PEK resin is injection-molded, the mold temperature is about 160 to 200 ° C., and the resin temperature is about 360 to 410 ° C. If the base material has oil adhesion or oil impregnation, the residue of the oil decomposed and gasified during the injection molding of the resin layer is present at the interface, which may reduce the adhesion between the resin layer and the base material. is there. Therefore, it is preferable to use a sintered metal member not impregnated with oil for the base material. In addition, when oil is used in the process of forming or repressing (sizing) a sintered metal member, the oil should be removed by steam cleaning or a non-oil-containing sintered metal member that has been steamed. preferable.

  The density of the sintered metal of the base material is preferably set to a theoretical density ratio of 0.7 to 0.9. The theoretical density ratio of the material is the ratio of the density of the base material when the theoretical density of the material (density when the porosity is 0%) is 1. By making it within this range, it is possible to ensure the unevenness of the surface for obtaining adhesion, and at the same time to have high density and sufficiently ensure the thermal conductivity of the substrate. Moreover, since it is excellent in the joint strength of the joint part of a resin layer and a base material, even when used on severe conditions, such as a high surface pressure, it can prevent that a resin layer peels from a base material. If the theoretical density ratio is less than 0.7, the strength of the base material becomes low, and the base material may be cracked by the injection molding pressure at the time of insert molding. When the theoretical density ratio exceeds 0.9, the unevenness is reduced, so that the surface area and the anchor effect are lowered, and the adhesion with the resin layer is lowered. More preferably, the theoretical density ratio of the materials is 0.72 to 0.84. In addition, in order to further increase the shear adhesion strength between the base material and the resin layer, the surface of the sintered metal member forming the resin layer may be provided with physical stoppers such as irregularities and grooves, and a peripheral stopper. .

  Further, as the metal member that is the base material 5, a member made of molten metal manufactured by press working, machining, die casting or the like can also be adopted. Examples of the molten metal include steels such as bearing steel (SUJ1-5, etc.), chromium molybdenum steel, carbon steel for mechanical structure, mild steel, stainless steel, or high speed steel, aluminum, aluminum alloy, copper, copper alloy Is mentioned.

  When using molten metal as the metal material of the base material, the surface of the base material is made uneven by physical surface treatment such as shot blasting or machining before the resin layer is formed in order to improve the adhesion with the resin layer. Raging is preferred. Also, chemical surface treatment such as acidic solution treatment (mixed with sulfuric acid, nitric acid, hydrochloric acid, etc. or other solutions), alkaline solution treatment (mixed with sodium hydroxide, potassium hydroxide, etc. or other solutions) It is preferable to form a fine concavo-convex shape on at least the resin layer forming surface of the substrate. The acidic solution treatment is preferable because masking can be omitted. Although the fine uneven shape varies depending on the concentration, processing time, post-treatment, etc., in order to improve the adhesion due to the anchor effect, it is preferable to make the fine unevenness with a concave pitch of several nanometers to several tens of micrometers. The fine uneven shape formed by the chemical surface treatment has a complicated three-dimensional structure such as a porous structure, so that the anchor effect is easily exhibited, and particularly strong adhesion is possible. In addition, you may perform the process which forms a reactive chemical film on the base-material surface.

  A resin composition based on an aromatic PEK resin used for the resin layer will be described. Each resin layer uses an aromatic PEK-based resin as a base resin to obtain a highly reliable hemispherical shoe with excellent heat resistance, oil / chemical resistance, creep resistance, friction and wear characteristics, etc. Can do. In addition, since it has high toughness and mechanical properties at high temperatures and is excellent in fatigue resistance and impact resistance, it can be prevented from peeling from the substrate due to frictional force, impact, vibration, etc. during use.

  Examples of the aromatic PEK resin that can be used in the present invention include polyether ether ketone (PEEK) resin, polyether ketone (PEK) resin, and polyether ketone ether ketone ketone (PEKEKK) resin. Examples of commercially available PEEK resins that can be used in the present invention include Victrex PEEK (90P, 150P, 380P, 450P, 90G, 150G, etc.), Solvay Specialty Polymers: Keta Spire PEEK (KT-820P, KT). -880P, etc.), manufactured by Daicel Evonik Co., Ltd .: VESTAKEEEP (1000G, 2000G, 3000G, 4000G, etc.). Examples of the PEK resin include Victrex HT manufactured by Victrex, and examples of the PEKKK resin include Victrex ST manufactured by Victrex.

The resin composition forming the resin layer preferably has a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ . When the melt viscosity is within this range, a thin insert molding of 0.1 to 0.7 mm can be smoothly performed on the surface of the base material of the hemispherical shoe. Even when the resin flow path of the connecting portion of the resin layer between the spherical portion and the flat portion is narrow (FIGS. 2 and 3), the thin resin layer can be easily formed. By making thin insert molding possible and making post-processing after insert molding unnecessary, manufacturing becomes easy and manufacturing costs can be reduced.

  In the case of a resin composition having an aromatic PEK-based resin as a base resin, it is preferable to employ an aromatic PEK-based resin having a melt viscosity of 150 Pa · s or less under the above conditions in order to bring the melt viscosity to the above range. Examples of such aromatic PEK-based resins include VICTREX PEEK (90P, 150P, 90G, and 150G) manufactured by Victrex. Further, by using such an aromatic PEK-based resin, the resin material can easily enter the surface irregularities of the base material made of a sintered metal member or the like at the time of injection molding, and strong adhesion is possible.

  It is preferable to mix | blend compounding materials, such as PTFE resin, graphite, molybdenum disulfide, various whiskers, an aramid fiber, carbon fiber, in the resin composition which forms a resin layer. In particular, it is preferable to blend (1) PTFE resin and (2) at least one of carbon fiber and graphite. By blending the PTFE resin, low friction is obtained even under conditions of no lubrication and a thin lubricating oil, and seizure does not occur even in a dry state where there is no lubricating oil during operation. By blending at least one of carbon fiber and graphite, it is possible to improve creep resistance and friction and wear characteristics in oil lubrication, and to reduce the molding shrinkage of the resin composition.

  The blending ratio of each component in the resin composition forming the resin layer is based on aromatic PEK resin as a base resin, (1) 1 to 30% by volume of PTFE resin as an essential component, and (2) at least carbon fiber and graphite. It is preferable to contain one to 5-30 volume%. The balance excluding the essential components (1) and (2) and other small amount additives is an aromatic PEK resin. By using this blending ratio, the deformation and wear of the resin layer can be prevented even under high PV conditions, the damage to the swash plate and piston, which are counterpart materials, is small, and the resistance to oil is high. Does not burn even in dry conditions. Further, the PTFE resin is more preferably 2 to 25% by volume, and at least one of the carbon fiber and the graphite is more preferably 5 to 20% by volume.

  If the blending ratio of the PTFE resin exceeds 30% by volume, the wear resistance and creep resistance may be lowered from the required levels. Further, if the blending ratio of the PTFE resin is less than 1% by volume, the effect of imparting the required lubricity to the composition is poor, and sufficient sliding characteristics may not be obtained.

  If the blending ratio of at least one of carbon fiber and graphite exceeds 30% by volume, the melt fluidity is lowered and thin-wall molding may be difficult. In particular, when a large amount of carbon fiber is contained, there is a possibility that the swash plate or the piston as the counterpart material may be worn and damaged. Moreover, if it is less than 5 volume%, the effect which reinforces a resin layer is scarce, and sufficient creep resistance and abrasion resistance may not be obtained.

  As the PTFE resin, any of molding powder by suspension polymerization, fine powder by emulsion polymerization, and recycled PTFE may be used. In order to stabilize the fluidity of a resin composition comprising an aromatic PEK-based resin as a base resin, it is preferable to employ recycled PTFE which is difficult to be fiberized by shearing during molding and hardly increases the melt viscosity. Further, it may be a PTFE resin modified with a side chain group having a perfluoroalkyl ether group, a fluoroalkyl group, or another fluoroalkyl group.

  Regenerated PTFE is a powder that has been irradiated with a heat-treated powder (heated history added), γ-rays or electron beams. For example, a powder obtained by heat-treating molding powder or fine powder, a powder obtained by further irradiating this powder with γ-rays or an electron beam, a powder obtained by pulverizing a molding powder or a molded product of fine powder, and then a γ-ray or electron beam. There are types such as irradiated powder, molding powder or fine powder irradiated with gamma rays or electron beams. Among the recycled PTFE, it does not aggregate, does not fiberize at the melting temperature of the aromatic PEK resin, has an internal lubricating effect, and stabilizes the fluidity of the resin composition based on the aromatic PEK resin. It is more preferable to use PTFE resin irradiated with γ rays or electron beams.

  Examples of commercially available PTFE resins that can be used in the present invention include Kitamura Co., Ltd .: KTL-610, KTL-450, KTL-350, KTL-8N, KTL-400H, Mitsui DuPont Fluorochemical Co., Ltd .: Teflon (registered trademark). 7-J, TLP-10, Asahi Glass Co., Ltd .: Fullon G163, L150J, L169J, L170J, L172J, L173J, Daikin Industries, Ltd .: Polyflon M-15, Lubron L-5, Hoechst: Hostaflon TF9205, TF9207, etc. Can be mentioned. Among the PTFE resins irradiated with γ rays or electron beams among the above, Kitamura Co., Ltd .: KTL-610, KTL-450, KTL-350, KTL-8N, KTL-8F, Asahi Glass Co., Ltd .: Fullon L169J, L170J , L172J, L173J, and the like.

  The carbon fibers may be either pitch-based or PAN-based ones classified from raw materials, but PAN-based carbon fibers having a high elastic modulus are more preferable. The firing temperature is not particularly limited, but a carbonized product fired at about 1000 to 1500 ° C. is higher than that fired at a high temperature of 2000 ° C. or higher and converted to graphite (graphite). Even under PV, it is preferable because the swash plate and the piston, which are counterpart materials, are less likely to be damaged by wear. By using PAN-based carbon fiber as the carbon fiber, the elastic modulus of the resin layer is increased, and deformation and wear of the resin layer are reduced. Furthermore, the true contact area of the friction surface is reduced, and frictional heat generation is reduced.

  The average fiber diameter of the carbon fibers is preferably 20 μm or less, and more preferably 5 to 15 μm. A thick carbon fiber exceeding this range is not preferable because extreme pressure is generated, so that the effect of improving load resistance is poor, and depending on the material of the mating material, the wear damage of the mating material increases. The carbon fiber may be a chopped fiber or a milled fiber, but a milled fiber having a fiber length of less than 1 mm is preferable in order to obtain stable thin-wall formability.

  The average fiber length of the carbon fiber is preferably 0.02 to 0.2 mm. If the thickness is less than 0.02 mm, a sufficient reinforcing effect cannot be obtained, so that the creep resistance and wear resistance are poor. When the thickness exceeds 0.2 mm, the ratio of the fiber length to the thickness of the resin layer becomes large, so that the thin formability is inferior. In order to further improve the stability of thin-wall molding, the average fiber length is more preferably 0.02 to 0.1 mm.

  Examples of commercially available carbon fibers that can be used in the present invention include pitch-based carbon fibers manufactured by Kureha Co., Ltd .: Kureka M-101S, M-107S, M-101F, M-201S, M-207S, M-2007S, C- 103S, C-106S, C-203S and the like. Moreover, as a similar PAN-based carbon fiber, manufactured by Toho Tenax Co., Ltd .: Besfight HTA-CMF0160-0H, HTA-CMF0040-0H, HTA-C6, HTA-C6-S, or Toray Industries, Inc .: Torayca MLD-30 , MLD-300, T008, T010, and the like.

  Graphite is roughly classified into natural graphite and artificial graphite, and further includes flakes, granules and spheres, and any of them can be used. In order to increase the elastic modulus of the resin composition, improve the wear resistance and creep resistance, and obtain stable low friction characteristics, flake graphite is preferred.

  In addition, you may mix | blend a well-known resin additive with respect to a resin composition to such an extent that the effect of this invention is not inhibited. Examples of the additive include friction property improvers such as boron nitride and tungsten disulfide, thermal conductivity improvers such as carbon powder and metal oxide powder, and colorants such as carbon powder, iron oxide, and titanium oxide. It is done. In addition, particulate inorganic fillers such as calcium carbonate, calcium sulfate, mica and talc, thermosetting PI resins, wholly aromatic polyester resins, and non-melting organic fillers even at the injection molding temperature of the above resins such as aramid fibers Abrasion resistance improving material is mentioned.

  The means for mixing and kneading the above raw materials is not particularly limited, and only the powder raw material is dry-mixed with a Henschel mixer, ball mixer, ribbon blender, ladyge mixer, ultra Henschel mixer, etc. Melting and kneading can be performed with a melt extruder such as an extruder to obtain molding pellets of the resin composition. In addition, a side feed may be used for charging the filler when melt kneading with a twin screw extruder or the like. Using the pellets for molding, as described above, a resin layer is formed on the base material by injection molding (insert molding). Moreover, you may perform processes, such as annealing treatment, for physical property improvement after shaping | molding.

  The surface of the resin layer serving as a sliding surface with the swash plate or the piston may be polished after the resin layer is formed. The polishing process eliminates variations in individual height dimensions and improves accuracy. Moreover, it is preferable to adjust the surface roughness of the surface of the resin layer to 0.05 to 1.0 μm Ra (JIS B0601). By setting it within this range, the real contact area on the sliding surface of the resin layer sliding with the swash plate or the piston is increased, the actual surface pressure can be lowered, and seizure can be prevented. If the surface roughness is less than 0.05 μmRa, the supply of lubricating oil to the sliding surface is insufficient. If the surface roughness is more than 1.0 μmRa, the actual contact area on the sliding surface is reduced, resulting in high local pressure. There is a risk of sticking. More preferably, the surface roughness is 0.1 to 0.5 μmRa.

  Oil pockets and dynamic pressure grooves may be formed on the surface of the resin layer serving as the sliding surface with the swash plate or the piston in addition to the above-described hollow portion in order to supplement the lubricating action during lean lubrication. Examples of the shape of the oil pocket include a spot-like or streak-like recess. Examples of the spot shape or the stripe shape include a parallel straight line shape, a lattice shape, a spiral shape, a radial shape, and a ring shape. The depth of the oil pocket can be determined as appropriate below the thickness of the resin layer.

  The swash plate type compressor in which the hemispherical shoe of the present invention is used is a swash plate that is fixed to the rotating shaft directly or indirectly through a connecting member at right angles and obliquely in a housing where refrigerant exists. This is a swash plate type compressor that compresses and expands the refrigerant by sliding a hemispherical shoe and converting the rotational motion of the swash plate into a reciprocating motion of the piston through the hemispherical shoe. By using the hemispherical shoe of the present invention in the swash plate compressor, the lubricating coating can be removed from the swash plate and the piston that slide with the hemispherical shoe. That is, the surface of the swash plate or the like can be incorporated in the swash plate compressor and slid with the hemispherical shoe while the surface of the substrate remains the polished surface. Therefore, it is possible to provide a low-cost swash plate compressor that is functionally equivalent.

  The hemispherical shoe of the swash plate compressor of the present invention is formed by thin insert molding a resin layer having a predetermined composition on the surface of a metal base material, so that seizure occurs even in a dry lubrication state without lubricating oil at the start of operation. In addition, the durability is sufficiently ensured since there is no deterioration of the lubrication characteristics due to frictional heat generation and peeling of the resin layer. Therefore, it can be used for various swash plate compressors. In particular, carbon dioxide gas or HFC1234yf is used as a refrigerant, and it can be suitably used for a recent swash plate type compressor having a high-speed and high-load specification.

DESCRIPTION OF SYMBOLS 1 Housing 2 Rotating shaft 3 Swash plate 4 Hemispherical shoe 5 Base material (metal member)
6 Resin layer 7 Hollow portion 8 Non-contact portion 9 Piston 10 Cylinder bore 11 Needle roller bearing 12 Thrust needle roller bearing 13 Spherical seat

Claims (7)

In the housing in which the refrigerant is present, the hemispherical shoe is slid on a swash plate mounted at right angles and obliquely so as to be directly fixed to the rotating shaft or indirectly through the connecting member, and the hemispherical shoe is passed through the hemispherical shoe. A hemispherical shoe for a swash plate type compressor that compresses and expands the refrigerant by converting the rotational movement of the swash plate into the reciprocating movement of the piston,
The hemispherical shoe has a resin layer on the surface of a flat surface portion that slides with the swash plate and the surface of the spherical surface portion that slides with the piston, using a metal member as a base material.
Each thickness of the resin layer of the plane part and the resin layer of the spherical part is 0.1 to 0.7 mm, and the resin layer of the planar part and the resin layer of the spherical part are aromatic polyether ketones A hemispherical shoe for a swash plate compressor, wherein a resin composition comprising a resin as a base resin is integrally formed on the surface of the substrate by injection molding.   2. A hemispherical shoe for a swash plate compressor according to claim 1, wherein said metal member is a member made of iron-based sintered metal, and the density thereof is a theoretical density ratio of 0.7 to 0.9.   The resin composition includes 1 to 30% by volume of a polytetrafluoroethylene resin and 5 to 30% by volume of at least one of carbon fiber and graphite, respectively, based on the entire resin composition. A hemispherical shoe for a swash plate compressor according to claim 1. 4. The hemisphere of a swash plate compressor according to claim 1, wherein the resin composition has a melt viscosity of 50 to 200 Pa · s at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ . Shoe. In the housing in which the refrigerant is present, the hemispherical shoe is slid on a swash plate mounted at right angles and obliquely so as to be directly fixed to the rotating shaft or indirectly through the connecting member, and the hemispherical shoe is passed through the hemispherical shoe. A swash plate type compressor that compresses and expands refrigerant by converting the rotational movement of the swash plate into the reciprocating movement of the piston,
The swash plate compressor, wherein the hemispherical shoe is the hemispherical shoe according to any one of claims 1 to 4.   6. The swash plate compressor according to claim 5, wherein a sliding surface of the swash plate with the hemispherical shoe is a polished surface of a swash plate substrate and does not have a lubricating coating.   The swash plate compressor according to claim 5 or 6, wherein the refrigerant is carbon dioxide gas.

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