JP2020007972A - Hemispherical shoe for swash plate type compressor and method for manufacturing the same - Google Patents

Abstract

To provide a hemispherical shoe that neither causes any seizure even in a dry state with lubricant shortage at operation start nor causes deterioration in lubrication property due to frictional heat generation and sufficiently ensures durability, and can be used without detachment of a resin layer that comes into slide contact with a swash plate even in a high vibration environment, and to provide a method for manufacturing the same.SOLUTION: A hemispherical shoe 4 includes a substrate 5 and a resin layer 6 that is formed by injection molding. A spherical surface part 4a coming into slide contact with a piston includes the substrate 5. A flat surface part 4b coming into slide contact with a swash plate includes the resin layer 6. The substrate 5 is a metal sintered compact that is subjected to sealing process with a thermosetting resin.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hemispherical shoe for converting rotational motion of a swash plate into reciprocating motion of a piston, interposed between the swash plate and a piston, and a method of manufacturing the same, in a swash plate compressor used for an air conditioner for an automobile or the like.

  A swash plate compressor is provided with a hemispheric shoe on a swash plate attached at an angle (right angle and obliquely) in a housing where a refrigerant is present, to be directly fixed to a rotating shaft or indirectly through a connecting member. The swash plate is slid and the rotational motion of the swash plate is converted into reciprocating motion of the piston via the hemispherical 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 swash plate type compressor that compresses and expands refrigerant only on one side using a single-headed piston. There is a board type. Further, the hemispherical shoe may be slid on only one side surface of the swash plate, or may be slid on both side surfaces of the swash plate. In these swash plate compressors, the sliding surface between the swash plate and the hemispherical shoe slides at a large relative speed of 20 m / s or more, and the hemispherical shoe is used in a very severe environment.

  The lubrication of the swash plate compressor is diluted while the lubricating oil dissolves in the refrigerant, circulates in the housing, and is supplied to the sliding portion in the form of a mist. However, since the lubricating oil is washed away at the start of operation, the sliding surface between the swash plate and the hemispherical shoe at the start of operation tends to be in a dry state without lubricating oil, and seizure is likely to occur. .

  As means for preventing this seizure, for example, a resin layer is formed by injection molding on a flat portion of a metal base material which is a sliding portion with a swash plate, and an annular band portion is formed on the resin layer to prevent peeling. (Patent Document 1), and a resin layer formed by injection molding on a spherical portion of a metal base material in order to impart slidability to sliding with a piston (Patent Document 2, 3) has been proposed. Patent Document 4 discloses a method of forming a resin layer on a spherical portion and a flat portion of a metal base material by injection molding.

JP 2014-202193 A JP-A-2006-023623 JP-A-2006-023624 JP-A-2006-44608

  Patent Literature 1 is characterized in that the layer thickness of the resin layer in the annular band portion is, for example, twice or more the layer thickness of the central portion and the outer edge portion. However, the physical properties such as strength tend to decrease as the thickness of the resin layer increases, and thus the configuration having such an annular band portion may have insufficient physical properties.

  Patent Literature 1 discloses that a sintered body is used as a metal base material. However, if the surface pressure of the sintered body is too high during sliding, the lubricating oil is guided to the pores inside the sintered body, and the lubricating oil escapes to a lower surface pressure. Therefore, the oil film may be extremely thin between the sintered body and the counterpart material, or the oil film may be broken, and the friction and wear characteristics may be reduced.

  Further, in the hemispheric shoes described in Patent Literature 2 and Patent Literature 3, since most of the metal base material is covered with the resin layer, heat generated due to sliding resistance cannot be released, and The layer may melt.

  The present invention has been made to address these problems, and even in a dry state without lubricating oil at the start of operation, seizure does not occur, lubrication characteristics do not decrease due to frictional heating, and durability is sufficient. It is an object of the present invention to provide a hemispherical shoe which is secured to a swash plate and can be used without peeling even in a high vibration environment even in a high vibration environment, and a method for manufacturing the same.

  The hemispheric shoe of the swash plate type compressor according to the present invention includes a hemispheric shoe mounted on a swash plate mounted at right angles and obliquely, in a housing where a refrigerant is present, so as to be directly fixed to a rotating shaft or indirectly via a connecting member. The swash plate is a swash plate type compressor that slides, converts the rotational movement of the swash plate into a reciprocating motion of a piston through the hemispherical shoe, compresses and expands the refrigerant, and the hemispherical shoe includes a base material. The spherical part sliding on the piston is made of the base material, the flat part sliding on the swash plate is made of the resin layer, and the base material is sealed with a thermosetting resin. It is a metal sintered body that has been subjected to a hole treatment.

  The thermosetting resin is an epoxy resin.

  The main component of the resin layer is a polyetheretherketone (PEEK) resin.

  The porosity of the metal sintered body sealed with the thermosetting resin is 0.5% or more and less than 5%.

  The method for manufacturing a hemispherical shoe of the swash plate type compressor of the present invention is a method for manufacturing the hemispherical shoe of the present invention, wherein after sealing a thermosetting resin in the metal sintered body, the flat surface of the metal sintered body is formed. The resin layer is insert-molded with a thermoplastic resin in the portion.

  After the insert molding of the resin layer, the surface of the resin layer is polished.

  The hemispheric shoe of the swash plate compressor of the present invention is a metal sintered body whose base material is sealed with a thermosetting resin. In this case, it is possible to prevent the lubricating oil from leaking from the high surface pressure side to the low surface pressure side. In addition, since the sliding part with the swash plate is made of a resin layer, the sliding part with the piston is made of the base material itself, so heat is released to the piston and lubricating oil through the base material, so that heat dissipation Excellent. Therefore, the resin layer can be prevented from being dissolved even in a dry state at the start of operation. Further, since the lubricating oil can be held in the concave portions (voids) on the surface of the base material, the sliding characteristics with the piston are excellent.

  In addition, by forming the base material of the hemispheric shoe as a metal sintered body sealed with a thermosetting resin, the resin enters the recesses (voids) on the surface of the base material during the injection molding of the resin layer, and due to the anchor effect, The substrate and the resin layer can be firmly adhered. Therefore, even in a high-speed, high-temperature, and high-vibration environment, the resin layer in sliding contact with the swash plate can be used without peeling. Further, in the configuration of the hemispheric shoe, since the sliding portion with the swash plate having a long sliding distance is made of the resin layer and the sliding portion with the piston is made of the base material, excellent slidability is obtained.

  Since the thermosetting resin is an epoxy resin, it has excellent heat resistance.

  Since the main component of the resin layer is a PEEK resin, a hemispheric shoe excellent in strength and heat resistance can be obtained.

  Since the porosity of the metal sintered body sealed with the thermosetting resin is 0.5% or more and less than 5%, the communication hole (the air connected from one surface to a different surface) of the metal sintered body. Holes) are almost disappeared, and the lubricating oil can be prevented from being pushed out through the communication holes. When the porosity is 0.5% or more, voids remain on the surface of the base material, and an improvement in lubricating oil holding power and an anchor effect with the resin layer can be obtained.

  The method for manufacturing a hemispherical shoe of the swash plate compressor of the present invention is that, after sealing the thermosetting resin in the metal sintered body, the resin layer is insert-molded with the thermoplastic resin on the flat portion of the metal sintered body. By performing insert molding after increasing the relative density of the metal sintered body by the sealing process, the molding accuracy is excellent. Further, voids are formed on the surface of the substrate due to the dimensional shrinkage of the thermosetting resin during the sealing treatment, and the thermoplastic resin enters the voids, so that the resin layer and the substrate can be firmly adhered.

  Since the surface of the resin layer is polished after the insert molding of the resin layer, the resin thickness can be improved by reducing the layer thickness, and the accuracy of geometric tolerance such as flatness can be improved. Further, since a contact portion with a mold called a skin layer can be removed, friction and wear characteristics are stabilized.

It is a longitudinal section showing an example of the swash plate type compressor of the present invention. It is a longitudinal cross-sectional view which expands and shows the hemisphere shoe of this invention. It is a schematic diagram of the manufacturing method of the hemispheric shoe of the present invention. FIG. 4 is a diagram illustrating a portion where a thermosetting resin remains.

  An embodiment of the swash plate type 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 the swash plate type compressor of the present invention. The swash plate type compressor shown in FIG. 1 uses carbon dioxide gas as a refrigerant. In a housing 1 in which the refrigerant exists, the swash plate 3 which is attached obliquely so as to be directly fixed to a rotating shaft 2 performs a swash plate rotation. It is converted into a reciprocating motion of a double-headed piston 14 via a hemispherical shoe 4 sliding on both sides of the plate 3, and a refrigerant is formed on both sides of each piston 14 in a cylinder bore 10 formed at equal intervals in the circumferential direction of the housing 1. Is a swash plate type that compresses and expands. The rotating shaft 2 driven to rotate at a high speed is supported by needle roller bearings 11 in the radial direction, and is supported by needle roller bearings 12 in the thrust direction. In this configuration, the swash plate 3 may be fixed to the rotating shaft 2 indirectly via a connecting member. In addition, a mode may be adopted in which it is attached not at an angle but at a right angle.

  A concave portion 14a is formed in each piston 14 so as to straddle the outer peripheral portion of the swash plate 3, and a hemispheric shoe 4 is seated on a spherical seat 13 formed on an axially opposed surface of the concave portion 14a. The swash plate 3 is supported so as to be relatively movable with respect to the rotation. Thereby, the conversion from the rotational movement of the swash plate 3 to the reciprocating movement of the piston 14 is performed smoothly. The hemisphere shoe 4 has a spherical portion sliding with the piston 14 (spherical seat 13) and a flat portion sliding with the swash plate 3.

  The structure of the hemispheric shoe will be described in detail with reference to FIG. FIG. 2 is a longitudinal sectional view showing an example of the hemispheric shoe of the present invention. As shown in FIG. 2, the hemispheric shoe 4 includes a spherical portion 4 a forming a part of a sphere, a flat portion 4 b formed by cutting the sphere in a substantially flat surface on the opposite side of the spherical portion 4 a, and a spherical portion 4 a. It has a substantially hemispherical structure including an outer peripheral portion 4c connecting the flat portion 4b. The semispherical shoe 4 has a circular planar shape, and the surface of the outer peripheral portion 4c is a cylindrical outer peripheral surface. The overall shape of the hemispherical shoe 4 is a shape in which one bottom surface of the columnar body is a convex shape forming a part of the hemisphere. The overall shape of the hemispherical shoe 4 is not limited to this, and it is sufficient that the hemispherical shoe 4 has a flat portion sliding on the swash plate and a spherical portion sliding on the piston. ) May be used.

  The hemispherical shoe 4 includes a base material 5 and a resin layer 6 formed by injection molding. The shape of the base member 5 is substantially the same as the overall shape of the hemispherical shoe 4, and corresponds to the spherical portion 4 a, the flat portion 4 b, and the outer peripheral portion 4 c of the hemispherical shoe 4, respectively. 5c. In the base member 5, a resin layer 6 is formed on the surface of the flat portion 5b. On the other hand, the resin layer 6 is not formed on the surfaces of the spherical portion 5a and the outer peripheral portion 5c. For this reason, the surface of the flat portion 4b of the hemispheric shoe 4 serving as the sliding surface with the swash plate is made of the resin layer 6, and the surface of the spherical portion 4a of the hemispheric shoe 4 serving as the sliding surface with the piston is formed of the base material. 5 is the spherical portion 5a itself. Even if frictional heat is generated due to sliding with the swash plate, the heat can be released from the spherical portion 5a and the outer peripheral portion 5c of the base member 5, and the resin layer can be prevented from melting.

  The resin layer 6 is an injection molded layer formed by injection molding using a predetermined synthetic resin. As will be described later, the resin layer is formed by setting a base material of a hemispherical shoe in an injection molding die, and performing insert molding (integral injection molding) of a synthetic resin thereon. Forming the resin layer by injection molding eliminates the need for masking as in the case of forming a lubricating film, does not increase the number of extra manufacturing steps, and can suppress an increase in price.

  The base member 5 has a concave portion 8 having a shape depressed from the surface of the flat portion 5b and a hollow portion 7 penetrating the spherical portion 5a side and the flat portion 5b side in the central axis portion. The resin layer 6 is filled to a certain depth of the hollow portion 7. This part is the filling part 6c. The resin layer 6 is formed along the recess 8. The portion 6b formed along the concave portion 8 is integral with the flat portion 6a and has substantially the same thickness. The surface of the resin layer 6 (the surface of the flat portion 6a) serving as a sliding surface with the swash plate is a flat surface, and its layer thickness is constant.

  The central circular concave portion 8 on the surface of the flat portion 5b of the base member 5 and the hollow portion 7 (resin-unfilled portion) of the center axis portion of the base member 5 serve as a lubricating oil reservoir. Lubricating oil is held in this portion, which can supplement the lubricating action at the time of lean lubrication and prevent seizure. In addition, the contact area between the resin layer 6 and the base material 5 increases when the concave shape as described above is present, and the peeling of the resin layer 6 can be further prevented as compared with the case where the entire surface of the flat portion 5b is a flat surface. Further, as described later, from the viewpoint of injection molding, by providing a gate at this concave position, it is possible to prevent a gate mark (convex portion) after the gate cut from protruding on the swash plate sliding surface. Further, the hollow portion 7 not filled with the resin becomes an exposed portion of the base material 5 and has an increased exposed area together with the spherical portion 5a, so that the heat dissipation is excellent.

  The hemispheric shoe of the present invention is characterized in that the substrate 5 is a metal sintered body sealed with a thermosetting resin (hereinafter, also referred to as a sealed body). The metal sintered body has a porous structure having many pores, and the pores are sealed with a thermosetting resin. The porosity of the sealed body is, for example, 0.5% or more and less than 5%, preferably 1% or more and less than 5%, and more preferably 1% or more and less than 3%. When the porosity is less than 5%, the communication holes of the metal sintered body disappear, so that it is possible to prevent the lubricating oil from being extruded through the communication holes. Further, by setting the porosity to 0.5% or more, a concave portion remains on the surface of the base material, and retention of lubricating oil and an anchor effect can be expected.

  The porosity of the metal sintered body and the pore-treated body is measured by the method for measuring open porosity described in JIS Z2501: 2000.

  Examples of the material of the metal sintered body include sintered metals such as iron, copper-iron, copper, and stainless steel. Among these sintered metal materials, it is preferable to use a sintered metal containing iron as a main component and an iron-based sintered metal having a copper content of 10% by weight or less.

  Examples of the thermosetting resin include an epoxy resin, an acrylic resin, a phenol resin, a urea resin, and an unsaturated polyester resin. Among these, it is preferable to use an epoxy resin because of its excellent heat resistance. Further, the epoxy resin shrinks appropriately during curing, and a concave portion is formed on the surface of the base material.

  Examples of the epoxy resin that can be used in the present invention include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, hydrogenated bisphenol A epoxy resin, hydrogenated bisphenol F epoxy resin, stilbene epoxy resin, Triazine skeleton-containing epoxy resin, fluorene skeleton-containing epoxy resin, alicyclic epoxy resin, novolak type epoxy resin, acrylic epoxy resin, glycidylamine type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, biphenyl Type epoxy resin, a dicyclopentadiene skeleton-containing epoxy resin, a naphthalene skeleton-containing epoxy resin, an arylalkylene type epoxy resin, and the like.

  As shown in FIG. 2, the resin layer 6 is a thin layer formed along the shape of the surface of the flat portion 5 b of the substrate 5. When the diameter R of the hemispherical shoe is about 10 mm (about 5 to 16 mm), the thickness t of the resin layer is preferably 0.05 mm to 0.5 mm. In the present invention, the preferred ranges (mm) of the other dimensions shown below are intended for hemispheric shoes having a diameter of about 5 to 16 mm. By setting the thickness of the resin layer in such a thin range, frictional heat easily escapes from the frictional sliding surface to the base material side, and it is difficult to store heat. If the thickness is less than 0.05 mm, the substrate may be exposed when the resin layer is polished, depending on the planar accuracy of the substrate. If the thickness is more than 0.5 mm, the heat dissipation and the surface pressure resistance are reduced due to the increase in the volume of the resin layer, and the resin layer is liable to be deformed. In the case where the resin layer is formed only by injection molding without polishing, the thickness of the resin layer is 0.3 mm or more. This is because if the thickness is smaller than 0.3 mm, it becomes difficult to form a resin layer by injection molding even if a resin material having low fluidity is used.

  As the synthetic resin forming the resin layer, a thermoplastic resin which can be injection-molded and has excellent lubricating properties and heat resistance is preferable. Examples of such a thermoplastic resin include PEEK resin, polyacetal (POM) resin, polyphenylene sulfide (PPS) resin, injection moldable polyimide resin, polyamide imide (PAI) resin, polyamide (PA) resin, and the like. . Each of these resins may be used alone, or may be a polymer alloy in which two or more kinds are mixed.

  Among these synthetic resins, it is preferable to use PEEK resin as a main component. By using PEEK resin, it is possible to obtain a highly reliable hemispheric shoe having excellent heat resistance, oil / chemical resistance, creep resistance, friction and wear characteristics, and the like.

  The resin layer is a resin composition in which the above PEEK resin is blended with a solid lubricant such as polytetrafluoroethylene (PTFE) resin, graphite, molybdenum disulfide, and various whiskers, aramid fibers, and carbon fibers. It is preferably made of a material. Note that the solid lubricant has low friction even under a condition where the lubricating oil is diluted, and can suppress seizure.

The resin composition forming the resin layer preferably has a melt viscosity at a resin temperature of 380 ° C. and a shear rate of 1000 s ⁻¹ of 50 Pa · s to 5000 Pa · s. When the melt viscosity is in this range, thin insert molding of the resin layer on the surface of the base material of the hemispherical shoe can be performed smoothly.

  The method for manufacturing a hemispheric shoe according to the present invention is a method for manufacturing the above-mentioned hemispheric shoe, and the manufacturing method includes the following steps (a) to (c). That is, (a) a sealing step of sealing a metal sintered body with a thermosetting resin, and (b) a molding step of insert-molding a resin layer with a thermoplastic resin on the sealed metal sintered body. And (c) a polishing step of polishing the resin layer. As shown in FIG. 3, the (a) sealing step includes (a1) an impregnation step of impregnating the metal sintered body with a thermosetting resin and (a2) a thermosetting step of curing the thermosetting resin. Including.

  First, the metal sintered body used in the step (a) is manufactured by a general manufacturing method. Specifically, a raw material powder including a metal powder such as an iron-based, copper-iron-based, copper-based, and stainless steel-based material is charged into a forming mold and compressed to form a substantially hemispherical green compact (compacted powder). Process). The green compact is obtained by putting the green compact into a sintering furnace and sintering it at a predetermined temperature.

  The porosity of the obtained metal sintered body (the metal sintered body before the sealing treatment) is, for example, 10% or more and 40% or less. The porosity is preferably 10% or more and 30% or less in order to maintain sufficient strength as a base material while enabling sufficient impregnation of the pores inside the metal sintered body.

  The average diameter of the pores of the obtained metal sintered body is preferably fine to obtain a desired capillary force upon impregnation, for example, 200 μm or less, preferably 150 μm or less, more preferably 100 μm or less It is. On the other hand, from the point of molding, the average diameter of the pores of the metal sintered body is usually 5 μm or more. The average diameter of the pores of the sintered body is measured, for example, by analyzing an enlarged image of the surface or the cross section.

(A) Sealing Step- (a1) Impregnation Step The metal sintered body is impregnated (filled) with a thermosetting resin. Specifically, a method of immersing a part or all of the metal sintered body in a resin solution of a thermosetting resin or a method of applying the resin solution to the surface of the metal sintered body is used.

  As described above, it is preferable to use an epoxy resin as the thermosetting resin. In this case, it is preferable that the viscosity of the epoxy resin solution used in the impregnation step is low in consideration of the impregnation property of the metal sintered body. For example, the viscosity of the epoxy resin solution is preferably 50 Pa · s or less. Such an epoxy resin solution is obtained by diluting the epoxy resin to a predetermined concentration with a diluent such as an organic solvent.

  As a method of dipping in the obtained resin solution, a vacuum impregnation method is preferable. The vacuum impregnation method is a method in which a metal sintered body is immersed in an epoxy resin solution and then evacuated to impregnate the pores. A method of dipping in a resin solution is used. The vacuum impregnation method will be specifically described. First, the metal sintered body is placed in a container half filled with an epoxy resin solution. At this time, the metal sintered body is placed on the upper part of the container with a wire net or the like so as not to touch the epoxy resin solution. The container is hermetically sealed and evacuated using a rotary pump or the like to remove air inside the container. In this case, it is preferable that the pressure in the evacuated container is 10 Pa or less. In addition, the inside of the container is heated to 40 ° C. or more and less than 80 ° C. This heating lowers the viscosity of the epoxy resin solution, so that the epoxy resin solution easily penetrates into the pores of the metal sintered body.

  Then, the metal sintered body is immersed in the epoxy resin solution in the container while being evacuated, and then the pressure in the container is released. With the release of the reduced pressure, the epoxy resin solution enters the pores of the metal sintered body by the pressure of the air flowing into the container. After immersion for a predetermined time, the epoxy resin solution attached to the surface of the metal sintered body is removed. The removal of the resin solution is performed by wiping or the like.

(A) Sealing Step-(a2) Thermosetting Step The metal sintered body impregnated with the thermosetting resin is subjected to a heat treatment, and the thermosetting resin is cured to obtain a sealing treatment body.

  Specifically, the metal sintered body impregnated with the thermosetting resin is placed in a thermostat, and is sufficiently cured at a temperature equal to or higher than the thermosetting start temperature of the thermosetting resin (for example, 150 to 200 ° C.) and normal pressure. (For example, 60 minutes or more) to cure the thermosetting resin. The curing temperature range and the curing time are appropriately set depending on the thermosetting resin or the like. Also, in order to prevent the metal sintered body and the pedestal of the thermostatic bath from adhering during thermosetting, the metal sintered body impregnated with the thermosetting resin is fixed to the pedestal plane with the spherical part side down, The jig may be fixed through the hollow portion of the shaft portion.

  The mode of the sealing step is not limited to the above method. The type of the thermosetting resin, the solution viscosity, the impregnation time, the impregnation amount, the porosity of the metal sintered body, and the like are adjusted so that the porosity of the sealed body becomes 0.5% or more and less than 5%. Is preferable.

(B) Injection molding step The sealed body is fixed to an injection mold, and insert-molded through a gate into a cavity corresponding to the shape of the resin layer shown in FIG. Specifically, a gate is provided in a concave portion which is depressed from the surface of the flat portion of the base material (sealing-treated body), and a resin composition melted from the gate is injected and filled in a molding cavity. At this time, the sealed body is heated to the mold temperature (about 200 ° C.) in advance. By doing so, it is possible to prevent the temperature of the mold from lowering and to prevent molding failure. In addition, injection molding can be performed without reducing the cycle time by preheating. Then, after passing the holding pressure, it is cooled for a certain period of time, and the mold is opened to obtain an injection molded body.

(C) Polishing Step The surface of the resin layer (the surface of the flat portion) serving as a sliding portion with the swash plate is polished. Generally, the surface of a resin layer formed by injection molding is called a skin layer, and is rapidly cooled and solidified by contact with a mold. . However, in order to satisfy this requirement, the layer thickness must be 0.1 mm or less, but it is difficult to reduce the layer thickness to 0.4 mm or less by injection molding. Therefore, it is preferable to polish the surface of the resin layer formed by injection molding.

  By this polishing process, there is no variation in individual height dimensions in the resin layer, and the accuracy is greatly improved. In addition, the surface roughness of the resin layer is preferably adjusted to 0.1 μmRa to 1.0 μmRa (JIS B0601) by this polishing. By setting it within this range, the real contact area on the sliding surface of the resin layer that slides on the swash plate increases, and the actual surface pressure can be reduced to prevent seizure. When the surface roughness is less than 0.1 μm Ra, the supply of lubricating oil to the sliding surface is insufficient. When the surface roughness exceeds 1.0 μm Ra, a high contact pressure locally occurs due to a decrease in the real contact area on the sliding surface, and There is a risk of sticking. More preferably, the surface roughness is from 0.2 μmRa to 0.8 μmRa.

  As described above, by performing the steps (a) to (c) in this order, the hemispheric shoe shown in FIG. 2 is manufactured. In the manufacturing method of the present invention, the injection molding step is performed after the sealing step. If the sealing step is performed after the injection molding step, the thermosetting resin is left unwiped in the depressed area A of the resin layer and the outer peripheral area B of the hemispherical shoe as shown in FIG. The curable resin may remain. Then, after incorporating the hemispherical shoe into the swash plate type compressor, the curable resin may fall off and adversely affect the curable resin. For this reason, in the present invention, the thermosetting resin is prevented from remaining on the sliding surface side with the swash plate by integral injection molding after the impregnation sealing hole. In addition, by performing the steps in this order, the relative density of the metal sintered body increases, so that the molding accuracy of the injection molding increases.

  The swash plate type compressor in which the hemispheric shoe of the present invention is used is mounted on a swash plate attached at a right angle and obliquely, in a housing where a refrigerant is present, so as to be directly fixed to a rotating shaft or indirectly through a connecting member. This is a swash plate compressor that slides a hemispheric shoe, converts the rotational movement of the swash plate into a reciprocating motion of a piston through the hemispheric shoe, and compresses and expands the refrigerant. By using the hemispheric shoe of the present invention in the swash plate compressor, the lubricating coating can be removed from the swash plate that slides on the hemispheric shoe. That is, the swash plate surface can be incorporated into the swash plate compressor and slid with the hemispheric shoe while the polished and turned surfaces of the base material remain as they are. For this reason, it is possible to provide a low-cost swash plate type compressor that is equivalent in function. In addition, as a base material of the swash plate, a steel material such as carbon steel for machine structure (S45C), a hot-rolled steel plate for automotive structure (SAPH440), and spheroidal graphite cast iron (FCD), a copper alloy, or the like can be used.

  The hemispheric shoe of the swash plate type compressor of the present invention does not cause seizure even in a dry state without lubricating oil at the start of operation, has no deterioration in lubrication characteristics due to frictional heat generation, and has sufficient durability. Further, since the resin layer on the flat surface portion of the hemispherical shoe does not peel off due to the vibration during use and the shearing force received from the swash plate, it can be used for various swash plate compressors. In particular, the present invention can be suitably used for a recent swash plate type compressor which uses carbon dioxide gas or HFC1234yf as a refrigerant and has a high-speed and high-load specification.

DESCRIPTION OF SYMBOLS 1 Housing 2 Rotation shaft 3 Swash plate 4 Hemispheric shoe 5 Base material 6 Resin layer 7 Hollow part 8 Concave part 10 Cylinder bore 11 Needle roller bearing 12 Thrust needle roller bearing 13 Spherical seat 14 Piston

Claims (6)

In the housing where the refrigerant is present, the hemispheric shoe is slid on a swash plate attached at right angles and obliquely so as to be directly fixed to the rotating shaft or indirectly via a connecting member, and the A hemispherical shoe of a swash plate type compressor that converts the rotational motion of the swash plate into a reciprocating motion of a piston to compress and expand the refrigerant,
The hemispheric shoe is made of a base material and a resin layer formed by injection molding, a spherical portion sliding with the piston is made of the base material, and a flat portion sliding with the swash plate is made of the resin layer,
A hemispheric shoe for a swash plate compressor, wherein the base material is a metal sintered body sealed with a thermosetting resin.   The hemispheric shoe of a swash plate type compressor according to claim 1, wherein the thermosetting resin is an epoxy resin.   3. The swash plate type compressor according to claim 1, wherein a main component of the resin layer is a polyetheretherketone resin.   The porosity of the metal sintered compact sealed with the thermosetting resin is 0.5% or more and less than 5%, The porosity of Claim 1 characterized by the above-mentioned. Hemisphere shoe for swash plate type compressor. A method for producing a hemispherical shoe for a swash plate type compressor according to any one of claims 1 to 4,
A method for manufacturing a hemispherical shoe for a swash plate compressor, comprising sealing a thermosetting resin in a metal sintered body and then insert-molding a resin layer with a thermoplastic resin on a flat surface of the metal sintered body.   The method for manufacturing a hemispherical shoe for a swash plate type compressor according to claim 5, wherein the surface of the resin layer is polished after the insert molding of the resin layer.

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