Bearings and Compressors

Abstract

To improve the seizure resistance.SOLUTION: A bearing 10 comprises a tubular substrate 12 and a resin layer 14. The resin layer 14 is joined to an inner peripheral surface C1 of the substrate 12, and, in a surface on the side of a surface C2 facing a shaft member that is received on the inner peripheral surface C1 side of the substrate 12, a plurality of grooves MG are provided along the direction that intersects the direction Z of extension of the shaft member. The resin layer 14 contains a synthetic resin 16 and an additive 18 dispersed in the synthetic resin 16. The average particle size of the additive 18 is less than the depth d of the grooves MG.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bearing and a compressor. [Background technology]

[0002] Conventionally, a cylindrical bearing has been known to have a groove formed on the inner peripheral surface thereof in order to improve seizure resistance by oil retention. For example, a bearing layer on a substrate has been disclosed in which a groove is formed. Another bearing layer on a substrate is disclosed in which a resin layer containing an additive such as graphite is used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5683571 [Patent Document 2] Japanese Patent Application Publication No. 2018-193521 Summary of the Invention [Problem to be solved by the invention]

[0004] The grooves are formed by, for example, cutting a resin material layer provided on a substrate. However, additives contained in the resin layer can make it difficult to form grooves in the desired shape. For this reason, conventional techniques have been unable to form grooves properly, resulting in insufficient seizure resistance.

[0005] An object of the present invention is to provide a bearing and a compressor that can improve seizure resistance. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the bearing of the present invention comprises a cylindrical substrate, and a resin layer joined to the inner surface of the substrate, the surface facing the shaft member housed on the inner surface side of the substrate having a plurality of grooves along a direction intersecting the extension direction of the shaft member, the resin layer containing a synthetic resin and an additive dispersed in the synthetic resin, wherein the average particle size of the additive is less than the depth of the grooves. The additive contains at least one of graphite and clay, the graphite has an average particle size of 1.0 μm or more and less than 4.0 μm, the clay has an average particle size of 2.0 μm or more and less than 3.5 μm, and the groove depth is 4 μm or more and 7 μm or less. [Effects of the Invention]

[0007] According to the present invention, it is possible to improve seizure resistance. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1A is an explanatory diagram of an example of the overall configuration of a bearing according to an embodiment. [Figure 1B] FIG. 1B is an explanatory diagram of an example of the overall configuration of a bearing according to an embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view of an example of a bearing. [Figure 3A] FIG. 3A is an explanatory diagram of an example of a method for manufacturing a bearing. [Figure 3B] FIG. 3B is an explanatory diagram of an example of a method for manufacturing a bearing. [Figure 4] FIG. 4 is an explanatory diagram of an example of a conventional comparative bearing. [Figure 5] FIG. 5 is a schematic diagram of an example of a compressor. [Figure 6] FIG. 6 is an explanatory diagram of the seizure resistance test. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a bearing and a compressor according to the present invention will be described in detail with reference to the accompanying drawings.

[0010] The bearing of this embodiment includes a cylindrical substrate and a resin layer. The resin layer is bonded to the inner peripheral surface of the substrate. The resin layer has a plurality of grooves formed on its surface facing the shaft member housed on the inner peripheral surface of the substrate, the grooves extending in a direction intersecting the extension direction of the shaft member. The resin layer contains a synthetic resin and an additive dispersed in the synthetic resin. The average particle size of the additive is less than the depth of the grooves.

[0011] In the bearing of this embodiment, the average particle size of the additive contained in the resin layer is less than the depth of the groove, which makes it easier to form the groove and improves seizure resistance.

[0012] The reason why the above-mentioned effect is exhibited is not clear, but is speculated as follows: However, the present invention is not limited to the speculation below.

[0013] If the average particle size of the additives contained in the resin layer is greater than or equal to the depth of the grooves, it may be difficult to form the grooves in the desired shape. Furthermore, if the average particle size of the additives contained in the resin layer is greater than or equal to the depth of the grooves, the additives may fall off during groove processing, resulting in significant defects in the groove shape, preventing the grooves from being formed in the desired shape. If it becomes difficult to form grooves in the desired shape, it may be impossible to stably demonstrate bearing performance, including seizure resistance, resulting in problems with the quality of the bearing product. Furthermore, if the average particle size of the additives contained in the resin layer is greater than or equal to the depth of the grooves, it may be impossible to maintain the desired groove shape during sliding contact with the shaft member.

[0014] On the other hand, it is presumed that when the average particle size of the additive contained in the resin layer is less than the depth of the groove, the grooves of the desired shape are suitably formed. It is also presumed that the formation of the grooves of the desired shape realizes the suitable oil film retention of the lubricating oil by the grooves, thereby improving the lubrication performance and improving the seizure resistance.

[0015] The bearing and compressor of this embodiment will be described in detail below.

[0016] 1A and 1B are explanatory diagrams of an example of the overall configuration of a bearing 10 of this embodiment. Fig. 1A is a cross-sectional view of the bearing 10 cut in a direction intersecting the extension direction Z of the bearing 10. Fig. 1B is an external view of the bearing 10 viewed from a direction intersecting the extension direction Z of the bearing 10.

[0017] The bearing 10 includes a substrate 12 and a resin layer 14 .

[0018] The substrate 12 is a cylindrical member. In this embodiment, an example in which the substrate 12 is a cylindrical member will be described. Note that the substrate 12 may be any shape as long as it is cylindrical, and is not limited to a cylindrical shape.

[0019] The base material 12 is a member for accommodating the shaft member 30 on the inner peripheral surface C1 side. The shaft member 30 is a rod-shaped member that is long in the extension direction Z. In this embodiment, an example will be described in which the extension direction Z of the base material 12 and the extension direction Z of the shaft member 30 coincide with each other. However, the extension direction Z of the base material 12 and the extension direction Z of the shaft member 30 may not coincide with each other.

[0020] The resin layer 14 is a layer that is bonded to the inner peripheral surface C1 of the substrate 12. A plurality of grooves MG are provided on the surface of the resin layer 14 on the side of the surface C2 facing the shaft member 30, along a direction intersecting with the extension direction Z of the shaft member 30. The grooves MG along a direction intersecting with the extension direction Z mean grooves MG that are extended along a direction intersecting with the extension direction Z.

[0021] The grooves MG may be provided along a direction intersecting the extension direction Z of the shaft member 30, either perpendicular to the extension direction Z or inclined at an angle of less than 90° relative to the perpendicular direction. In this embodiment, an example will be described in which the grooves MG are provided along a direction perpendicular to the extension direction Z of the shaft member 30, i.e., along the circumferential direction Q of the cylindrical bearing 10. The grooves MG may be formed in a continuous spiral shape from one end to the other end of the extension direction Z in the resin layer 14. Note that the resin layer 14 may have a configuration in which a plurality of discontinuous grooves MG are provided from one end to the other end in the extension direction Z.

[0022] Next, the bearing 10 will be described in detail.

[0023] FIG. 2 is an enlarged cross-sectional view of an example of the bearing 10. As shown in FIG.

[0024] The bearing 10 is a laminate of a substrate 12 and a resin layer 14 formed on the substrate 12 .

[0025] The substrate 12 is a layer that provides mechanical strength to the bearing 10. The substrate 12 may also be referred to as a backing metal or a backing metal layer. The substrate 12 may be a metal plate made of, for example, an Fe alloy, Cu, or Cu alloy.

[0026] At least a portion of the surface of the substrate 12 that comes into contact with the resin layer 14 may be formed by a sintered layer. The sintered layer is a sintered body of metal powder, and is a porous layer having a plurality of pores. The metal powder that forms the sintered layer may be the same metal as the substrate 12, or may be a metal or material different from that of the substrate 12. By providing a sintered layer, it is possible to improve the adhesion between the substrate 12 and the resin layer 14.

[0027] As described above, the resin layer 14 is a layer that is bonded to the inner circumferential surface C1 of the base material 12. As described above, the resin layer 14 has a groove MG formed on the surface C2 facing the shaft member 30.

[0028] The groove portion MG is a micro-level fine and precise groove processed portion formed on the surface of the resin layer 14. The groove portion MG may also be called a micro-groove or a micro-groove.

[0029] The shape of the groove MG is not limited as long as the groove MG has a shape that can retain lubricating oil supplied when the bearing 10 is driven to rotate and can retain oil between the groove MG and the shaft member 30.

[0030] 2 shows an example in which the cross-sectional shape of the groove portion MG is V-shaped. However, the cross-sectional shape of the groove portion MG is not limited to V-shape. For example, the cross-sectional shape of the groove portion MG may be U-shaped, or may have a shape consisting of a flat bottom portion and a pair of side walls standing upright from the bottom portion.

[0031] The depth d and width of the groove MG are not limited, as long as the depth d and width of the groove MG are sufficient to retain the lubricating oil supplied when the bearing 10 is driven to rotate and to retain the oil between the groove MG and the shaft member 30.

[0032] The depth d of the groove portion MG represents the distance between the bottom B of the groove portion MG and the apex T of the mountain portion of the groove portion MG in the thickness direction of the resin layer 14. The width of the groove portion MG represents the distance between the centers of the bottoms B of adjacent groove portions MG.

[0033] The depth d of the groove MG is, for example, in the range of 4.0 μm to 7.0 μm, but is not limited to this range. The width of the groove MG is, for example, in the range of 0.045 mm to 0.145 mm, preferably in the range of 0.075 mm to 0.095 mm, but is not limited to this range. Furthermore, the groove MG is formed continuously in the width direction.

[0034] The resin layer 14 is a layer whose main component is a resin material. Specifically, the resin layer 14 is made of a synthetic resin 16 and an additive 18 dispersed in the synthetic resin 16.

[0035] There are no limitations on the composition of the synthetic resin 16. From the viewpoint of improving abrasion resistance, the composition of the synthetic resin 16 is preferably made of a heat-resistant resin.

[0036] For example, the synthetic resin 16 contains PTFE (polytetrafluoroethylene). In this embodiment, a form in which PTFE particles 16A, which are particulate PTFE, are dispersed in the synthetic resin 16 will be described as an example.

[0037] There are no limitations on the amount of PTFE particles 16A contained in the synthetic resin 16. For example, the amount of PTFE particles 16A contained in the synthetic resin 16 is preferably 5% by volume or more and 30% by volume or less, more preferably 10% by volume or more and 25% by volume or less, and particularly preferably 12% by volume or more and 20% by volume or less.

[0038] When the content of the PTFE particles 16A in the synthetic resin 16 is within the above range, the coefficient of friction of the resin layer 14 can be reduced. Furthermore, the PTFE particles 16A have high heat resistance and are difficult to dissolve or decompose. Therefore, by incorporating the PTFE particles 16A into the synthetic resin 16, the coefficient of friction of the resin layer 14 can be effectively reduced. In other words, by incorporating the PTFE particles 16A, the seizure resistance of the bearing 10 can be further improved.

[0039] The average particle size of the PTFE particles 16A is not limited. The average particle size of the PTFE particles 16A may be equal to or greater than the depth d of the groove portions MG or less than the depth d of the groove portions MG. Specifically, the average particle size of the PTFE particles 16A is, for example, preferably 1.0 μm or more and 25.0 μm or less, more preferably 1.0 μm or more and 15.0 μm or less, and particularly preferably 0.2 μm or more and 12.0 μm or less.

[0040] When the average particle size of the PTFE particles 16A is within the above range, the total surface area of ​​the PTFE particles 16A dispersed in the synthetic resin 16 increases. Therefore, even if the content of the PTFE particles 16A is lower within the above range, the coefficient of friction of the resin layer 14 can be reduced and the seizure resistance can be improved.

[0041] The average particle size of the PTFE particles 16A refers to the average primary particle size of the PTFE particles 16A. The average primary particle size refers to the cumulative 50% particle size of the volume average particle size. A scanning electron microscope (SEM) can be used to measure the average particle size of the PTFE particles 16A. The PTFE particles 16A are observed using an SEM at an appropriate magnification (for example, approximately 5000x), and the diameter of each of 100 primary particles is measured to calculate their volume. The cumulative 50% particle size can then be taken as the average primary particle size. Note that if the PTFE particles 16A are not spherical, the average of the major and minor diameters is considered to be the diameter of the primary particles.

[0042] The shape of the PTFE particles 16A is not limited. For example, the shape of the PTFE particles 16A may be either spherical or spheroidal. Furthermore, the method for producing the PTFE particles 16A is not limited. For example, the PTFE particles 16A may be any of PTFE particles produced by suspension polymerization, PTFE particles produced by emulsion polymerization, and recycled PTFE particles.

[0043] The synthetic resin 16 may further include one or more selected from the group consisting of PI (polyimide), PAI (polyamideimide), PBI (polybenzimidazole), PA (polyamide), phenol, epoxy, POM (polyacetal), PEEK (polyetheretherketone), PE (polyethylene), PPS (polyphenylene sulfide), and PEI (polyetherimide).

[0044] Moreover, from the viewpoint of strengthening the bond with the additive 18, the synthetic resin 16 may further contain a silane coupling agent.

[0045] Next, the additive 18 will be described.

[0046] The additive 18 is a substance for improving the properties of the resin layer 14. In this embodiment, the additive 18 means a substance other than a resin. That is, the additive 18 does not include a resin.

[0047] The average particle size of the additives 18 in this embodiment is less than the depth d of the groove portions MG. For example, the average particle size of the additives 18 must be less than 1 time the depth d of the groove portions MG, preferably less than 3 / 4 times the depth d of the groove portions MG, and more preferably less than 1 / 2 times the depth d of the groove portions MG.

[0048] It is believed that if the average particle size of additive 18 is less than the depth d of groove MG, groove MG of the desired shape will be suitably formed when bearing 10B is manufactured. By suitably forming groove MG of the desired shape, it is believed that the groove MG will have a suitable lubricant oil retention capacity, and seizure resistance can be improved.

[0049] The average particle size of the additives 18 may be measured by the following method. Specifically, for example, a cross section of the resin layer 14 in the direction along the stretching direction Z is photographed using an electron microscope at an appropriate magnification (for example, 1000 times) to obtain an electron image. Then, the area of ​​the additives 18 included in the obtained electron image is measured for each type of additive 18 using a general image analysis method, and converted into an average diameter assuming that the additives 18 are circular. By these processes, the average particle size for each type of additive 18 can be determined.

[0050] The additive 18 specifically includes at least one of graphite 20 and clay 22 .

[0051] By including graphite 20 in additive 18, it is possible to improve the seizure resistance of resin layer 14, for example.

[0052] As described above, the average particle size of additive 18 such as graphite 20 may be less than the depth d of groove portion MG. For example, assume that the depth d of groove portion MG is in the range of 4.0 μm to 7.0 μm. In this case, the average particle size of graphite 20 is, for example, preferably 1.0 μm to less than 4.0 μm, and more preferably 1.0 μm to less than 2.0 μm.

[0053] There are no limitations on the content of graphite 20 in synthetic resin 16. The content of graphite 20 in synthetic resin 16 is, for example, preferably 1 volume % or more and less than 15 volume %, more preferably 3 volume % or more and 12 volume % or less, and particularly preferably 5 volume % or more and less than 9 volume %.

[0054] When the content of the graphite 20 in the synthetic resin 16 is within the above range, the lipophilicity of the resin layer 14 can be improved, and the seizure resistance can be further improved.

[0055] There are no limitations on the shape of the graphite 20. For example, the shape of the graphite 20 may be either flaky or spherical. Note that the shape of the graphite 20 is preferably flaky.

[0056] "Flake-like" means that the shape is like a scale. Flake-like graphite 20 is a crystal in which many AB planes (hexagonal mesh planes, basal planes) that spread out in a plane due to carbon atoms forming an orderly network structure are stacked, and the crystal has a thickness in the C-axis direction perpendicular to the AB planes. The bonding strength due to van der Waals forces between the stacked AB planes is much weaker than the bonding strength in the in-plane direction of the AB planes, so shear is likely to occur between the AB planes. Therefore, the thickness of the flake-like graphite 20 in the stacking direction is thinner than the spread of the AB planes, and it is thin-plate-like overall.

[0057] When subjected to an external force, shear occurs between the A and B planes of the flake graphite 20, causing the flake graphite 20 to function as a solid lubricant. Therefore, by using the flake graphite 20 as the graphite 20 dispersed in the synthetic resin 16, it is possible to further improve the seizure resistance of the resin layer 14.

[0058] Furthermore, from the viewpoint of reducing the coefficient of friction, it is preferable that the graphite 20 has a high degree of graphitization. For example, the graphite 20 preferably has a degree of graphitization of 95% or more, and more preferably 99% or more.

[0059] The clay 22 is generally an Al2O3-SiO2-H2O clay mineral. The clay 22 may be calcined clay. When the additive 18 contains the clay 22, the abrasion resistance of the resin layer 14 can be improved.

[0060] As described above, the average particle size of the clay 22 may be less than the depth d of the grooves MG. For example, assume that the depth d of the grooves MG is in the range of 4.0 μm to 7.0 μm. In this case, the average particle size of the clay 22 is preferably, for example, 2.0 μm to 4.0 μm, and more preferably 2.0 μm to less than 3.5 μm.

[0061] There are no limitations on the content of clay 22 in synthetic resin 16. The content of clay 22 in synthetic resin 16 is, for example, preferably 1% by volume or more and 5% by volume or less, and more preferably 1% by volume or more and 3% by volume or less. When the content of clay 22 is within the above range, it is possible to improve the abrasion resistance of resin layer 14 and suppress a decrease in fatigue resistance.

[0062] (Bearing manufacturing method) The bearing 10 of this embodiment is manufactured, for example, by the following process.

[0063] 3A and 3B are explanatory diagrams of an example of a method for manufacturing bearing 10. FIG.

[0064] 3A, the resin material layer 15 is formed by applying the constituent material of the resin layer 14 having the above-described configuration onto the substrate 12 (resin material layer forming step). Then, the resin material layer 15 formed on the substrate 12 is dried. Known conditions may be used for the application and drying conditions.

[0065] Next, a groove processing step is performed. In this groove processing step, the cutting edge of a cutting tool is moved along the surface of the resin material layer 15, thereby scraping away the surface of the resin material layer 15 along the cut surface CS of the groove MG having the desired shape. This groove processing step produces a bearing 10 having a resin layer 14 with the groove MG formed therein, as shown in FIG. 3B.

[0066] The formation of the grooves MG is not limited to the formation by cutting the resin material layer 15 with a cutting tool. For example, the grooves MG may be formed by etching, a roller, or the like.

[0067] Here, the resin material layer 15 contains an additive 18. The larger the relative size of the additive 18 contained in the resin material layer 15 with respect to the groove portion MG, the more difficult it may be to process the groove portion MG. However, as described above, in this embodiment, the average particle size of the additive 18 is less than the depth d of the groove portion MG. Therefore, in this embodiment, even if the resin material layer 15 contains the additive 18, the groove portion MG can be easily formed.

[0068] Furthermore, when forming the grooves MG, additives 18 may fall off from the resin layer 14 due to cutting of the resin material layer 15, forming a fallen portion F on the surface of the resin layer 14 (see FIG. 3B). However, as described above, in this embodiment, the average particle size of additives 18 is less than the depth d of the grooves MG. Therefore, even if a fallen portion F is formed on the surface of the resin layer 14 due to the addition of additives 18 falling off during the formation of the grooves MG, the shape of the grooves MG in the bearing 10 of this embodiment will generally maintain the intended shape (see FIG. 3B). In other words, in this embodiment, it is possible to manufacture a bearing 10 having grooves MG with a reduced shape defect rate relative to the intended shape (i.e., normal).

[0069] On the other hand, in a conventional bearing in which the average particle size of the additive 18 is equal to or greater than the depth d of the groove MG, it may be difficult to form the groove MG in the desired shape.

[0070] 4 is an explanatory diagram of an example of a comparative bearing 1000. In the comparative bearing 1000, the average particle size of additives 19, such as graphite 21 and clay 23, dispersed in the synthetic resin 16 of the comparative resin layer 17 is equal to or greater than the depth d of the grooves MG. For this reason, in the comparative bearing 1000, the relative size of the additives 19 to the grooves MG is large, which can make it difficult to process the grooves MG into the surface of the resin material layer of the comparative resin layer 17.

[0071] Furthermore, in the comparative bearing 1000, the relative size of the detached portion F formed by the additive 19 being detached during the formation of the groove MG was large relative to the groove MG, and as a result, there were cases in which the groove MG was formed with a shape that was significantly deformed from the intended shape (see Figure 4). For this reason, the comparative bearing 1000 was unable to form a normal groove MG, and it was thought to be difficult to demonstrate stable bearing performance, resulting in quality problems as a bearing product.

[0072] On the other hand, in the bearing 10 of this embodiment, the average particle size of the additive 18 is less than the depth d of the groove MG. Therefore, in this embodiment, even if the resin material layer 15 contains the additive 18, the groove MG can be easily formed. Also, as shown in Figure 3B, the bearing 10 of this embodiment has a smaller shape defect rate for the groove MG with respect to the target shape than the conventional comparative bearing 1000, and it is thought that it is possible to manufacture a bearing 10 with groove MG that is closer to or matches the target shape.

[0073] Therefore, in this embodiment, by forming the grooves MG in the desired shape, it is believed that the grooves MG can provide a suitable lubricant oil retention force, and the seizure resistance of the bearing 10 can be improved.

[0074] (Compressor) Next, a description will be given of an example of an application of the bearing 10. The bearing 10 is used, for example, as a bushing in a fuel injection pump, various bearings, or a compressor.

[0075] Fig. 5 is a schematic diagram of an example of a compressor 40. The compressor 40 is an example of an application form of the bearing 10. Fig. 5 shows a scroll compressor as an example. Scroll compressors are used to compress gases such as refrigerant gas in, for example, air conditioners for automobiles, homes, trains, or businesses.

[0076] The compressor 40 has a cylindrical housing 41 with both ends closed. For example, the center of the housing 41 is disposed along the z-axis. The z-axis direction coincides with a direction parallel to the vertical direction. The +z direction is the vertical direction and may be referred to as the upward direction. The -z direction is the anti-vertical direction and may be referred to as the downward direction.

[0077] An intake pipe 44 that draws in atmospheric air is provided above the housing 41 (in the -z direction). A discharge pipe 46 that discharges compressed air stored in a chamber 45 inside the housing 41 is provided on the side of the housing 41. Inside the housing 41, a bearing 10 fixed to the housing 41 and a shaft member 30 rotatably supported by the bearing 10 are arranged along the z axis. That is, FIG. 5 shows an example in which the extension direction Z of the shaft member 30 and the bearing 10 coincides with the z axis direction, which is parallel to the vertical direction. In other words, FIG. 5 will explain an example in which the compressor 40 is a vertical compressor.

[0078] A fixed scroll member 47 having spiral blades is fixed to the upper part of the housing 41 of the compressor 40. A movable scroll member 48 having spiral blades wound in the opposite direction to the blades of the fixed scroll member 47 is disposed below the fixed scroll member 47 and faces the fixed scroll member 47. The movable scroll member 48 and the fixed scroll member 47 form a compression chamber.

[0079] The crank pin 30A is located at the top of the shaft member 30. When the shaft member 30 is driven to rotate by a motor 43 provided inside the housing 41, the crank pin 30A orbits. The crank pin 30A is housed in a pin receiver 48A provided below the movable scroll member 48, and orbits the movable scroll member 48 as the crank pin 30A orbits the movable scroll member 48.

[0080] When movable scroll member 48 orbits, air drawn in through suction pipe 44 flows into a compression chamber formed by movable scroll member 48 and fixed scroll member 47, where it is compressed and stored in chamber 45. Compressor 40 discharges the compressed air stored in chamber 45 from discharge pipe 46 to the outside.

[0081] Generally, a compressor 40 (air conditioner compressor) that compresses a refrigerant contains lubricating oil (refrigeration oil), and the lubricating oil is supplied to each bearing 10 by circulating the refrigerant. When the compressor is stopped, the refrigerant is not circulating, so no lubricating oil is supplied. Therefore, from the time of stopping to the initial start-up, the bearing 10 is lubricated only by the oil held (adhered) between the bearing 10 and the shaft member 30.

[0082] When the compressor 40 starts, the shaft member 30 is lubricated by the oil held between the bearing 10 and the shaft member 30, and the shaft member 30 is driven to rotate. If this oil runs out before the refrigerant starts circulating, seizure will occur.

[0083] In the bearing 10 of this embodiment, a groove portion MG is provided on the surface C2 of the resin layer 14 facing the shaft member 30.

[0084] For this reason, the grooves MG provided in the resin layer 14 increase the oil retention of the lubricating oil that has entered the gap between the bearing 10 and the shaft member 30. Therefore, when the compressor 40 starts, the resin layer 14 of the bearing 10 and the shaft member 30 are lubricated, and it is thought that oil shortage and seizure at the initial start of rotation of the shaft member 30 are suppressed.

[0085] Therefore, it is believed that the compressor 40 equipped with the bearing 10 of this embodiment can achieve improved seizure resistance.

[0086] 5 shows an example in which the compressor 40 is a vertical compressor. However, the compressor 40 may be a horizontal compressor in which the extension direction Z of the shaft member 30 and the bearing 10 coincides with the horizontal direction. The compressor 40 may also be in a form in which the extension direction Z of the shaft member 30 and the bearing 10 intersects with both the horizontal and vertical directions.

[0087] The timing for forming the grooves MG is not limited. For example, the grooves MG may be formed before the bearing 10 is attached to the compressor 40. In other words, the compressor 40 may be manufactured by attaching the bearing 10, on which the grooves MG have been formed, to the compressor 40.

[0088] Alternatively, the grooves MG may be formed by performing a groove processing step on the resin material layer 15 after mounting the bearing 10, which has a resin material layer 15 without the grooves MG formed therein, on the compressor 40. As described above, in the bearing 10 of this embodiment, the average particle size of the additives 18 contained in the resin material layer 15 is less than the depth d of the grooves MG to be formed. Therefore, in this embodiment, the grooves MG can be easily formed even if the resin material layer 15 contains the additives 18. In other words, in this embodiment, even when the grooves MG are formed after the bearing 10 is mounted on the compressor 40, the grooves MG of the desired shape can be easily formed with high precision. [Example]

[0089] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0090] Test pieces having the following resin layer 14 and comparative resin layers were prepared, and the seizure resistance of these test pieces was evaluated.

[0091] -Preparation of test specimens- A 1.5 mm thick steel plate (SPCC (JIS)) was prepared as the substrate 12. A solution of the constituent materials for the resin layer 14 was prepared by adding the additives shown in Examples 1 to 3 of Table 1 to synthetic resins having the compositions shown in Table 1. This solution was then applied to the substrate 12 by knife coating. After application, the solution was dried at room temperature to approximately 200°C for 60 to 90 minutes. The temperature was then raised to approximately 300°C and baked for 30 to 90 minutes. Through these steps, a resin material layer 15 was formed on the substrate 12. Furthermore, the cutting edge of a cutting tool was moved along the surface of the resin material layer 15, thereby scraping off the surface of the resin material layer 15 along the cut surfaces CS of the grooves MG of the desired shape. The desired shape was a groove MG with a depth d of 4.0 μm, a width of 0.075 μm, and a V-shaped cross section.

[0092] By these treatments, test pieces of the resin layer 14 of each of Examples 1 to 3 were prepared.

[0093] In addition, test pieces of the comparative resin layers 17 of Comparative Examples 1 to 3 were prepared in the same manner as the resin layers 14 of Examples 1 to 3, except that the synthetic resins and additives shown in Comparative Examples 1 to 3 in Table 1 were used as the constituent materials of the comparative resin layer 17.

[0094] The graphite used was flake-shaped graphite with a graphitization degree of 99%, and the clay used had the structural formula Al2O3·2SiO2.

[0095] [Table 1]

[0096] [Table 1]

[0097] -evaluation- -Seizure resistance- The test pieces of the example and the comparative example were evaluated for seizure resistance using a tester shown in FIG.

[0098] Fig. 6 is an explanatory diagram of the seizure resistance test. The groove MG side of a test piece corresponding to each of the resin layer 14 and the comparative resin layer 17 was placed facing the shaft member 30, and 45 mg of lubricant was applied to the surface of the groove MG side. Then, the shaft member 30 was rotated while applying a load, and the seizure resistance was evaluated. The evaluation was performed under the following conditions.

[0099] Testing machine: Seizure tester (see Figure 6) Load: 5Mpa ·Rotation speed (peripheral speed): 2m / s Test temperature (ambient temperature): 40°C Material of shaft member 30: SCM415 (Hv500 or more) Surface roughness of shaft member 30: Ra: 0.15 μm Lubricant: Liquid paraffin (viscosity: 4.4 x 10 -3 Pa·s) Lubrication method: Apply 45mg of lubricant Oil clearance: 100μm Seizure determination: Time (seconds) required from the start of rotation of the shaft member 30 until the friction torque reaches 4.8 N·m

[0100] The shaft member 30 was rotated under the above conditions, and the time (seconds) required from the start of rotation of the shaft member 30 until the friction torque reached 4.8 N m was measured as the time until seizure occurred. The time until seizure refers to the time required from the start of rotation of the shaft member 30 until seizure occurs. The measurement results are shown in Table 1. In Table 1, the longer the time until seizure occurred, the higher the seizure resistance, i.e., the more excellent the seizure resistance.

[0101] -Evaluation of improved seizure resistance with groove MG- As shown in Table 1, all of the test pieces of the example with the groove portion MG had a longer time until seizure than the test pieces of the comparative example without the groove portion MG. Therefore, the test pieces of the resin layer 14 of the example were evaluated to have higher seizure resistance than the test piece of the comparative example with the comparative resin layer 17.

[0102] -Groove shape machinability judgment- The test pieces of the example and the comparative example were evaluated for the shape workability of the grooves MG. The evaluation results are shown in Table 2.

[0103] As shown in Table 2, when the Gr grain size was smaller than the depth of the groove MG, the shape defect rate of the groove shape was small (normal shape). Also, as shown in Table 2, when the Gr grain size was larger than the depth of the groove MG, the shape defect rate of the groove shape was large (abnormal shape).

[0104] In detail, for the test specimen of the example and the test specimen of the comparative example, the surfaces of the grooves MG of the bearing 10 and the comparative bearing 1000 were traced along the extension direction Z with a roughness measuring device (SE-3400 manufactured by Kosaka Laboratory) to obtain a surface profile expansion curve of the grooves MG along the extension direction Z. Then, for each of the test specimens of the example and the test specimen of the comparative example, the average value av of the depths d of the multiple grooves MG included in the surface profile expansion curve and the standard deviation σ of the depths d of the grooves MG were calculated.

[0105] Furthermore, for each of the test pieces of the examples and the test pieces of the comparative examples, among the multiple groove portions MG included, groove portions MG with a depth d within the range of a standard deviation σ × 1 / 2 from the average value av were considered normal, and groove portions MG with a depth d outside this range were considered defective. For each of the test pieces of the examples and the test pieces of the comparative examples, if the proportion of groove portions MG determined to be defective among the multiple groove portions MG included was 20% or more, the groove portions MG were determined to have an abnormal shape. Furthermore, for each of the test pieces of the examples and the test pieces of the comparative examples, if the proportion of groove portions MG determined to be defective among the multiple groove portions MG included was less than 20%, the groove portions MG were determined to have a normal shape, and if 20% or more, the groove portions MG were determined to have an abnormal shape. The results of the determination are shown in Tables 1 and 2.

[0106] Furthermore, as shown in Table 2, all of the test pieces of the examples were judged to have normal shapes of the groove portions MG, while all of the test pieces of the comparative examples were judged to have abnormal shapes of the groove portions MG.

[0107] The various materials and compositions used in the above-described examples are merely examples, and the present invention is not limited to these. The resin layer 14 according to the present invention may further contain inevitable impurities. The specific structure of the bearing 10 is not limited to those illustrated in Figures 1A to 2. [Explanation of symbols]

[0108] 10 Bearings 12 Base material 14 Resin layer 16 Synthetic resin 16A PTFE particles 18 Additives 20 Graphite 22 Clay 40 Compressor

Claims

1. A cylindrical substrate; a resin layer that is bonded to the inner circumferential surface of the base material, that has a surface facing a shaft member that is accommodated on the inner circumferential surface side of the base material and that has a plurality of grooves that extend in a direction that intersects with the extension direction of the shaft member, and that contains a synthetic resin and an additive dispersed in the synthetic resin; Equipped with the average particle size of the additive is less than the depth of the groove; The additive is containing at least one of graphite and clay, The graphite has an average particle size of 1.0 μm or more and less than 4.0 μm, The clay has an average particle size of 2.0 μm or more and less than 3.5 μm, The depth of the groove is 4 μm or more and 7 μm or less. Bearing.

2. The synthetic resin contains PTFE particles.

2. The bearing according to claim 1.

3. A compressor comprising the bearing according to claim 1.

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