JP2016180381A - Hemispherical shoe of swash plate type compressor, and swash plate type compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hemispherical shoe, in the construction having a resin layer formed on the slide face of a hemispherical shoe, excellent in lubrication and abrasion proof properties of a resin layer even in the case of a lubrication shortage, and a swash plate type compressor using the hemispherical shoe.SOLUTION: A hemispherical shoe 4 slides on a swash plate and a piston of a swash plate type compressor. A metal member is used as a base material, and a resin layer 6b is formed on a surface of a plane part sliding with a swash plate. A surface of the resin layer 6b is formed with a plurality of circular lubrication grooves 7 (7a to 7c) that are individually have at their portions, overlapping parts 7d of the lubrication grooves 7a to 7c.SELECTED DRAWING: Figure 2

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 state with almost no 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.

  In addition, as a means for preventing the seizure in the hemispherical shoe in which the metal base material is a sliding surface, there has been proposed one in which a lubricating oil passage is formed using a laser (see Patent Document 4). In Patent Document 4, as shown in FIG. 7, a crater-like annular bulge 15 is irradiated by irradiating a sliding surface of a hemispherical shoe 14 made of SUJ2 with a YAG laser so as to draw many circles of the same diameter. And a lubricating oil passage 16 formed of a mesh-like concave portion through which the lubricating oil can flow is formed on the outer side in the radial direction.

JP 2002-180964 A JP 2003-049766 A JP 2002-039062 A JP 2006-307724 A

  However, the technique of Patent Document 4 is to form a lubricating oil passage by laser irradiation in a metal base material itself of a hemispherical shoe, and cannot be employed when a resin film (resin layer) is formed on a sliding surface. . Patent Documents 1 to 3 propose a method for forming a sliding surface of a swash plate or a hemispherical shoe with a resin film (resin layer) in order to improve the lubrication characteristics of the swash plate and the hemispherical shoe. As described above, since the hemispherical shoe is used in a very harsh environment, if the sliding surface is insufficiently lubricated, there is a possibility that the wear of the resin coating (resin layer) becomes very large. In these prior arts, no specific countermeasure is assumed in the case of insufficient lubrication on the surface of the resin layer or the like.

  In the first place, with these prior arts, there was actually no formation of a lubricious coating on the hemispherical shoe, although there was actually a lubrication coating on the swash 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 piston as in the prior art, the heat dissipation of the frictional heat is reduced and the temperature of the hemispherical shoe base material is increased. 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.

  In addition, the swash plate with a lubricating 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 lubricating coating made of expensive materials. There is a problem that you can not.

  The present invention has been made to cope with these problems. In a configuration in which a resin layer is formed on the sliding surface of the hemispherical shoe, the hemisphere is excellent in the lubrication characteristics and wear resistance characteristics of the resin layer even when the lubrication is insufficient. The purpose is to provide a shoe. Another object of the present invention is to provide a hemispherical shoe in which seizure does not occur, the lubrication characteristics are not lowered due to frictional heat generation, the resin layer is not peeled off, and durability is sufficiently secured. Furthermore, it aims at providing the swash plate type compressor which uses 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 a flat surface portion that slides on the swash plate, and a spherical surface portion that slides on the piston, a resin layer is formed on the surface of the flat portion, and a lubricating groove is formed on the surface of the resin layer. A plurality of the lubricating grooves are formed, and each of the plurality of lubricating grooves has a circular shape or a polygonal shape, and each of the lubricating grooves has an overlapping portion between the lubricating grooves.

  All of the plurality of lubricating grooves have the same shape, and the center points of the circle or the polygon are equidistant from the center point of the planar portion and are spaced apart at equal intervals in the circumferential direction. It is characterized by that.

  Each of the lubrication grooves has an open portion toward the outer peripheral end of the planar portion.

  A resin layer is formed on the surface of the spherical portion, the resin layer is a layer integral with the resin layer of the planar portion, and at least a part of the base material is exposed without being covered with the resin layer. It is characterized by that.

  The base material is formed with (1) a hollow portion that becomes a concave portion from the spherical portion side or the flat portion side, or (2) a hollow portion that penetrates the spherical portion side and the flat portion side at the central axis portion, At least a part of the hollow portion is exposed without being filled with the resin layer.

  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 hemispherical shoe of the swash plate compressor according to the present invention has a flat surface portion that slides with the swash plate and a spherical surface portion that slides with the piston, and a resin layer is formed at least on the surface of the flat surface portion. A plurality of lubrication grooves of circular or polygonal shape are formed, and each of the plurality of lubrication grooves has an overlapping portion of the lubrication grooves, so that lubricating oil is always stored between the swash plate and the hemispherical shoe. In addition, the lubricating oil can be supplied evenly to the hemispherical shoe flat surface. For this reason, a hydrodynamic lubrication system is provided, wear of the resin layer can be greatly reduced, and lubrication characteristics and wear resistance characteristics can be improved.

  The plurality of lubrication grooves are all the same shape, and the center points of the circles or polygons are equidistant from the center point of the plane portion, and are spaced apart at equal intervals in the circumferential direction. The effect can be maintained uniformly over the entire flat portion.

  Since each of the lubrication grooves has an open portion toward the outer peripheral end of the flat surface portion, the inflow of the lubricating oil into the lubrication groove can be promoted.

  A resin layer is formed on the surface of the spherical portion, the resin layer is a layer integral with the resin layer of the planar portion, and at least a part of the base material is exposed without being covered with the resin layer. Therefore, the heat dissipation and load resistance are excellent, and the slidability between both the swash plate and the piston is also excellent. Moreover, peeling of the resin layer from the base material can be prevented.

  The base material is formed with (1) a hollow portion that becomes a concave portion from the spherical portion side or the flat portion side, or (2) a hollow portion that penetrates the spherical portion side and the flat portion side at the central axis portion, Since at least a part of the hollow portion is exposed without being filled with the resin layer, the frictional heat is transmitted through the base material and is radiated to the outside from the exposed hollow portion. For this reason, it is excellent in abrasion resistance and seizure resistance. In addition, since the hollow portion is the heat radiating portion, it is easier to ensure a larger heat radiating portion area than when a part of the outer surface is the heat radiating portion.

  Since the swash plate compressor of the present invention is provided with the above-described hemispherical shoe, seizure on the sliding surface of the hemispherical shoe is possible even when the lubrication is insufficient, such as in a dry state where there is almost no lubricating oil at the start of operation. This is a swash plate compressor that has excellent durability, no deterioration in lubrication characteristics due to frictional heat generation, and no peeling of the resin layer.

It is a longitudinal cross-sectional view which shows an example of a swash plate type compressor. It is a top view which shows an example of the lubrication groove | channel of the resin layer of a hemispherical shoe plane part. It is a top view which shows the other example of the lubrication groove | channel of the resin layer of a hemispherical shoe plane part. It is a top view which shows the other example of the lubrication groove | channel of the resin layer of a hemispherical shoe plane part. It is sectional drawing which shows the cross-sectional shape of a lubrication groove. It is the longitudinal cross-sectional view and top view which expand and show a hemispherical shoe. It is a top view which shows the conventional hemispherical shoe.

  An example of the swash plate compressor of 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.

  Since the present invention is characterized in that the surface of the resin layer formed on the surface of the flat portion serving as a sliding surface with the swash plate has a predetermined-shaped lubricating groove, the structure of the hemispherical shoe 4 includes at least the flat portion. Any structure having a resin layer 6b on the surface of 4b may be used (see FIG. 6). Preferably, the resin layer 6a is also formed on the surface of the spherical surface portion 4a that serves as a sliding surface with the piston (see FIG. 6).

  The shape of the lubricating groove of the resin layer in the hemispherical shoe flat portion will be described with reference to FIGS. FIG. 2 is a plan view of the resin layer of the hemispheric shoe plane portion showing an example of the lubrication groove, and FIG. 3 is a plan view of the resin layer of the hemisphere shoe plane portion showing another example of the lubrication groove. As shown in FIG. 2, the surface of the resin layer 6 b in the flat portion of the hemispherical shoe 4 has a perfect circle shape. In the example shown in FIG. 2, three (7a-7c) circular (perfect circle) lubrication grooves are formed as the lubrication grooves 7 in the resin layer 6b in the planar portion. The lubrication grooves 7a to 7c all have the same diameter. Each of the lubricating grooves 7a to 7c has an overlapping portion 7d between the lubricating grooves in part. The overlapping portion 7d is a portion where an arbitrary lubricating groove and at least one other lubricating groove intersect and overlap each other. In this embodiment, one lubricating groove has two overlapping portions 7d each with the other two lubricating grooves. In the overlapping portion 7d, the lubricating oil held in each lubricating groove can be moved back and forth. With this structure, it is possible to prevent only the lubricating oil in some lubricating grooves from being exhausted and the like, and the entire hemispherical shoe flat portion is uneven. Lubricating oil can be supplied.

  In the example shown in FIG. 3, three (7a to 7c) circular (perfect circular) lubricating grooves are formed as the lubricating grooves 7, and each of the lubricating grooves is partially missing on the outer peripheral end side of the resin layer 6b. It has a different shape. In the lubricating grooves 7a to 7c, the lacking portions on the outer peripheral end sides become the open portions 7e. Each lubrication groove is opened to the outer peripheral side of the hemispherical shoe 4 at the opening 7e. With such a structure, the inflow of lubricating oil into each lubricating groove can be promoted. Further, each of the lubricating grooves 7a to 7c has an overlapping portion 7d between the lubricating grooves in part. In this example, as in the case of FIG. 2, one lubrication groove has two overlapping portions 7d each with the other two lubrication grooves.

  Here, the positional relationship between the lubricating grooves 7a to 7c will be described. The lubricating grooves 7a to 7c are all circular (perfect circles) having the same diameter. The center Oa of the lubrication groove 7a, the center Ob of the lubrication groove 7b, and the center Oc of the lubrication groove 7c are equidistant from the center point O of the resin layer 6b in the planar portion. That is, the three points Oa, Ob, and Oc exist on the same circle centered on the center point O of the plane portion. Further, the distance Lab on the circumference of Oa and Ob, the distance Lbc on the circumference of Ob and Oc, and the distance Lca on the circumference of Oc and Oa are the same. Oa, Ob, and Oc are spaced apart at equal intervals in the circumferential direction. By arranging in this way, each lubrication groove is equally spaced from the center of the plane part, and the distance between adjacent lubrication grooves is equal, and the lubrication effect can be kept uniform over the entire plane part. In the example shown in FIG. 2, the same positional relationship is secured.

  Further, the planar shape of the lubricating groove is not particularly limited to the circular shape (perfect circle) shown in FIGS. 2 and 3, and may be a circular shape (ellipse) or a polygonal shape. As long as it is a polygon, it may be a triangle, a quadrangle, a pentagon, or more. Further, a circle and a polygon may be used in combination, or polygons having different numbers of angles may be used in combination. The positional relationship may be formed randomly rather than at regular intervals as shown in FIGS. The number of lubricating grooves is preferably 3-6. If the number of lubrication grooves is two, the balance of the lubrication action on the sliding surface may be deteriorated. If the number of lubrication grooves is seven or more, the sliding area will be reduced, resulting in an increase in surface pressure on the resin layer. There is a risk of poor wear.

  FIG. 4 shows another example of the lubricating groove. In the example of FIG. 4A, four rectangular lubrication grooves 7 are formed in the resin layer 6 b in the flat portion of the hemispherical shoe 4. In the example of FIG. 4B, four circular (perfect circle) lubricating grooves 7 are formed in the resin layer 6b on the flat surface of the hemispherical shoe 4 and are arranged so as to be in contact with each other. In the example of FIG. 4C, six circular (perfect circle) lubricating grooves 7 are formed in the resin layer 6 b in the flat portion of the hemispherical shoe 4. In any case of FIGS. 4A to 4C, the respective lubricating grooves are equally spaced from the center of the flat portion, and the adjacent lubricating grooves have the same distance. In addition, as shown to Fig.4 (a), when the lubrication groove 7 is a square, the center is made into the intersection of a diagonal line.

  The cross-sectional shape of the lubricating groove is shown in FIG. FIG. 5 is an enlarged cross-sectional view of the vicinity of the sliding surface between the swash plate 3 and the resin layer 6b in the flat portion of the hemispherical shoe. In the present invention, the cross-sectional shape of the lubricating groove 7 is not particularly limited. For example, the circular shape (not-circular shape) in FIG. 5A, the square groove in FIG. 5B, the V groove in FIG. (D) Square grooves (with an introduction taper) and the like can be mentioned. Among these, it is possible to prevent the old lubricating oil from staying in the groove and to smoothly supply the lubricating oil to the lubricating surface, and therefore it is preferable to have a circular shape (a missing circular shape) in FIG.

  The groove depth of the lubricating groove is preferably 0.05 mm or more and 2/3 or less of the thickness of the resin layer (for example, about 0.1 to 0.7 mm). Within this range, the lubrication effect and ensuring the strength of the resin layer can be satisfied. If the groove depth is shallower than 0.05 mm, the lubricating oil may not be sufficiently supplied. Further, if the groove depth is more than 2/3 of the thickness of the resin layer, the mechanical strength of the groove portion may be reduced and cracks may occur.

  The groove width of the lubricating groove is preferably in the range of 0.05 mm or more and 3 times or less the thickness of the resin layer (for example, about 0.1 to 0.7 mm). Within this range, a sufficient sliding area can be secured while having a lubricating effect. If the groove width is narrower than 0.05 mm, the lubricating oil may not be sufficiently supplied. Further, if the groove width exceeds 3 times the thickness of the resin layer, the sliding area is reduced, so that the surface pressure on the resin layer is increased and the wear resistance may be deteriorated.

  An example of the structure of the hemispherical shoe will be described with reference to FIG. 6 is a longitudinal sectional view showing an example of the hemispherical shoe of the present invention, and the lower view of FIG. 6 is a plan view thereof. As shown in FIG. 6, the hemispherical shoe 4 includes a spherical portion 4a constituting a part of the sphere, a flat portion 4b in a form obtained by cutting the sphere 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 uses a metal member as a base material 5 and has a resin layer 6 formed 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. The above-mentioned lubrication groove is formed on the surface of the resin layer 6b of the flat portion 4b. In addition, when there exists a recessed part etc. which provide the gate at the time of injection molding in the center part of the resin layer 6b, the above-mentioned lubrication groove | channel is not formed in this part.

  The resin layer 6b of the flat surface portion 4b and the resin layer 6a of the spherical surface portion 4a are continuous resin layers via the resin layer 6c of the outer peripheral portion 4c, and are integrally formed so as to cover the surface of the base material 5. . In the case where the diameter of the hemispherical shoe is about 10 mm (5 to 15 mm), the thickness of the resin layer covering the outside of the base material 5 is about 0.1 to 0.7 mm, and the shape of the base material 5 is that of the hemispherical shoe 4. It is a shape along the entire shape. It is preferable to make the resin layer as thin as the above-mentioned range since the frictional heat easily escapes from the frictional sliding surface to the substrate side and is difficult to store heat. 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.

  The hemispherical shoe 4 is covered with a resin layer 6 at other locations while forming the resin layer 6 on the sliding surface of the metal base material 5 directly with both the piston and the swash plate. It is preferable to have no exposed part. By providing such an exposed portion, even if frictional heat due to sliding between the swash plate and the piston is generated, heat can be transferred from the exposed portion through the base material, and the resin layer can be dissolved. Excellent wear resistance and seizure resistance. The position and form of the exposed portion of the base material are not particularly limited as long as they are other than the direct sliding surfaces with both the piston and swash plate members, but because of excellent workability and heat dissipation, (1 ) A hollow part that becomes a concave part from the spherical part side or the flat part side, or (2) a hollow part that penetrates the spherical part side and the flat part side is formed, and at least a part of the hollow part is filled with a resin layer The form exposed without being preferable is preferable.

  In the form shown in FIG. 6, the base material 5 is formed with a cylindrical space-like hollow portion 5 a penetrating the spherical surface portion 4 a side and the flat surface portion 4 b side at the center axis portion of the circular center. The hollow portion 5a is filled with the resin layer 6d from the flat 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 5a, frictional heat is radiated from the portion to the outside. The exposed portion also functions as an oil pocket that holds the lubricating oil.

  The axial length of the exposed portion of the hollow portion 5a is preferably at least one third of the height of the hemispherical shoe. By setting it as this range, the area of a thermal radiation part can be enlarged and it is excellent in heat dissipation. The diameter of the hollow portion 5a is preferably in the range of 1/6 to 1/3 of the diameter of the hemispherical shoe 4. By making it within this range, it is possible to prevent the strength of the base material from being lowered while ensuring heat dissipation.

  The hemispherical shoe 4 of the form shown in FIG. 6 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 exposed without being covered with the resin layer 6 in the non-contact portion 8. Yes. 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. In this form, the planar shape of the non-contact part 8 is circular. 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.

  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. The resin layers 6a and 6b formed on these surfaces are integrated integrally with the resin layer 6c formed on the outer peripheral portion 4c so that the resin is structurally double-sided (planar portion and spherical portion). The layer is difficult to peel from the substrate.

  The synthetic resin (base resin) for forming the resin layer is not particularly limited as long as it can ensure the lubrication characteristics and heat resistance required for the hemispherical shoe. For example, polyphenylene sulfide (PPS) resin, polyamideimide (PAI) ) Resin, polyether ether ketone (PEEK) resin, polyimide (PI) resin, phenol resin and the like. Each of these synthetic resins may be used alone or may be a polymer alloy in which two or more kinds are mixed. Among these, PAI resin, PEEK resin, and PI resin excellent in heat resistance and wear resistance are preferable, and PEEK resin excellent in fatigue characteristics and fluidity during injection molding is particularly preferable. These synthetic resins may be blended with carbon fiber, glass fiber, mica, talc and the like for the purpose of improving wear resistance. Further, for the purpose of reducing friction and improving seizure resistance when oil is exhausted, polytetrafluoroethylene (PTFE) resin, graphite, molybdenum disulfide, or the like may be blended.

  As a method for forming the resin layer, injection molding, spray coating, powder coating, or the like can be employed. Of these, injection molding is preferred because an inexpensive and dense resin layer can be formed. In injection molding, since a pressure is applied to a resin composition in a molten state, a resin layer is densely formed, and load resistance and wear resistance are increased. As an injection molding method, for example, a method in which a base material of a hemispherical shoe is set in a mold, and a synthetic resin is injection molded (insert molding) from the top can be adopted. In addition, when the resin layer is formed by injection molding, the resin layer may be machined to a desired dimension after injection molding, in addition to being molded once to a desired dimension by injection molding. The above-mentioned lubricating groove can also be easily formed simultaneously with the formation of the resin layer. Further, the lubricating groove may be formed by post-processing after injection molding.

  Examples of the metal member that is a base material include a member made of melted metal manufactured by pressing, machining, die casting, or the like. In addition, as the molten metal, for example, steel 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, A copper alloy is mentioned. In addition, when using molten metal as a metal material of a base material, in order to improve adhesiveness with a resin layer, it is preferable to form uneven | corrugated shape by physical surface treatment or chemical surface treatment.

  In addition, a sintered metal member having a concavo-convex surface can be employed as the metal member that is a base material. When a sintered metal is used as the metal material of the substrate, 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 can be increased. In particular, by forming the resin layer by insert molding, the resin layer bites into the irregularities on the surface of the sintered metal during injection molding, and the true bonding area increases, so the adhesion strength between the resin layer and the substrate improves. . 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.

  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 as long as the lubricating performance of the lubricating groove is not deteriorated. 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 lubricating oil is insufficiently supplied to the sliding surface. If the surface roughness exceeds 1.0 μmRa, the surface area is locally increased due to a decrease in the real contact area on the sliding surface, and seizure occurs. There is a fear. More preferably, the surface roughness is 0.1 to 0.5 μmRa.

  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. Moreover, 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.

  Since the hemispherical shoe of the swash plate compressor of the present invention has a resin layer formed on the sliding surface of the hemispherical shoe, the resin layer is excellent in lubrication and wear resistance even when lubrication is insufficient. Available to:

DESCRIPTION OF SYMBOLS 1 Housing 2 Rotating shaft 3 Swash plate 4 Hemispherical shoe 5 Base material (metal member)
6 Resin layer 7 Lubrication groove 8 Non-contact part 9 Piston 10 Cylinder bore 11 Needle roller bearing 12 Thrust needle roller bearing 13 Spherical seat 14 Hemispherical shoe 15 Annular bulging part 16 Lubricating oil passage

Claims (6)

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 metal member as a base material, has a flat surface portion that slides with the swash plate, and a spherical surface portion that slides with the piston, and a resin layer is formed on the surface of the flat surface portion,
A plurality of lubrication grooves are formed on the surface of the resin layer, each of the plurality of lubrication grooves has a circular shape or a polygonal shape, and each has a portion where the lubrication grooves overlap each other. Hemispherical shoe for swash plate compressor.   All of the plurality of lubricating grooves have the same shape, and the center points of the circles or polygons are equidistant from the center point of the planar portion, and are spaced apart at equal intervals in the circumferential direction. The hemispherical shoe for a swash plate compressor according to claim 1.   The hemispherical shoe for a swash plate compressor according to claim 1 or 2, wherein each of the plurality of lubricating grooves has an opening portion toward the outer peripheral end of the flat portion. A resin layer is formed on the surface of the spherical portion,
The resin layer is a layer integral with the resin layer of the flat portion, and at least a part of the base material is exposed without being covered with the resin layer. A hemispherical shoe for a swash plate compressor according to claim 3.   The base material is formed with (1) a hollow portion that becomes a concave portion from the spherical surface side or the flat surface portion side, or (2) a hollow portion that passes through the spherical surface side and the flat surface portion side at the central axis portion, The hemispherical shoe for a swash plate compressor according to claim 4, wherein at least a part of the hollow portion is exposed without being filled with the resin layer. 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 5.

Images