CN111315985A

CN111315985A - Swash plate

Info

Publication number: CN111315985A
Application number: CN201880069834.4A
Authority: CN
Inventors: 多胡泰之; 后藤真吾; 秋月政宪; 速水裕树
Original assignee: Taiho Kogyo Co Ltd
Current assignee: Taiho Kogyo Co Ltd
Priority date: 2017-10-31
Filing date: 2018-10-31
Publication date: 2020-06-19
Also published as: US20200355174A1; KR20200070347A; JP2019082148A; WO2019088163A1; DE112018005083T5

Abstract

The present invention solves the problem of inhibiting irregular wear on a resin coating. The swash plate according to one embodiment has: a substrate having a ring shape, the substrate having a surface facing the mating material; a plurality of grooves provided on the surface and extending in a direction intersecting with a direction of sliding contact with the mating material over an entire circumference of the ring shape; and a resin coating layer formed on the surface and forming a sliding contact surface with the mating material.

Description

Swash plate

Technical Field

The present invention relates to a swash plate for a swash plate type compressor.

Background

In a swash plate in which a resin coating is formed on a base material, a technique of forming grooves on the surface of the resin coating is known (for example, patent documents 1 to 3).

Documents of the prior art

Patent document

Patent document 1: JP-A-2006-266139

Patent document 2: JP-A-2014-151499

Patent document 3: WO 2002/075172

Disclosure of Invention

Problems to be solved

The inventors of the present application found that the problems are: the formation of the grooves on the base material in the swash plate may cause uneven wear of the resin coating formed on the base material.

The present invention provides a technique for suppressing uneven wear of such a resin coating.

Technical scheme

The present invention provides a swash plate, including: an annular substrate comprising a surface facing the mating member; a plurality of grooves extending in a direction intersecting with a sliding direction of the engaging member along an entire circumference of the ring shape on the surface; and a resin coating layer formed on the surface and forming a sliding surface with the mating member.

The plurality of grooves may extend radially from a center of the ring shape.

Among the plurality of grooves, a distance between adjacent grooves may be 20 μm to 240 μm.

The surface may have a roughness of 5 μm RzJIS to 15 μm RzJIS.

Effects of the invention

According to the present invention, uneven wear of the resin coating can be suppressed.

Drawings

Fig. 1 is a schematic sectional view showing the structure of a compressor 1 according to an embodiment of the present invention.

Fig. 2 shows an exemplary shape of the swash plate 3.

Fig. 3 shows an exemplary sectional structure of the swash plate 3.

Fig. 4 shows an exemplary surface shape of the base material 31.

Fig. 5 shows an exemplary shape of the groove 312.

Fig. 6 shows an exemplary surface shape of the coating 32.

Fig. 7 shows abnormal wear.

Fig. 8 is an exemplary flowchart of a method for manufacturing the swash plate 3.

Fig. 9 shows the surface shape of the base material 31 in the examples and comparative examples.

Fig. 10 is a schematic view of the surface state of the resin coating layer after the abrasion test.

Detailed Description

1. Structure of the device

Fig. 1 is a schematic sectional view showing the structure of a compressor 1 according to an embodiment of the present invention. The compressor 1 is a so-called swash plate compressor. The compressor 1 includes a shaft 2, a swash plate 3, pistons 4, and shoes 5. The shaft 2 is rotatably supported with respect to a housing (not shown in the drawings). The swash plate 3 is fixed at an angle inclined with respect to the rotation axis of the shaft 2. The swash plate 3 is an example of a sliding member according to the present invention. The piston 4 reciprocates in a cylinder bore (not shown in the figure) provided in the housing. The shoes 5 are disposed between the swash plate 3 and the pistons 4, and slide together with each of the swash plate 3 and the pistons 4. The surface of the shoe 5 on which the swash plate 3 slides is substantially flat; while the surface on which the piston 4 slides is arched (has a hemispherical shape). According to the present invention, the slipper 5 is an example of a fitting member that slides together with the sliding member. The swash plate 3 converts rotation of the shaft 2 into reciprocating motion of the pistons 4.

Fig. 2 shows an exemplary shape of the swash plate 3. Fig. 2 is a view seen from a direction perpendicular to the axial sliding surface. The swash plate 3 is disc-shaped (doughnut-shaped or annular) and is provided with a hole 39 at the entire center. The shoes 5 rotate on the sliding surface as viewed from the swash plate 3. Here, the rotation refers to a movement in which the slipper 5 draws an arc-shaped or circular locus with respect to the swash plate 3. For example, with respect to the sliding surface on the compression chamber side, a force is applied toward the compression chamber at a position where the piston 4 is completely withdrawn (the compression ratio is lowest) to a position where the piston is completely inserted (the compression ratio is highest), so that the shoes 5 slide along with the swash plate 3. However, when the piston 4 moves from the fully inserted position toward the fully retracted position, a force is applied to the opposite side of the compression chamber, and therefore, the shoe 5 can be made to float away from the sliding surface of the swash plate 3. This is the reason why the trajectory is arc-shaped. The hole 39 is a hole for receiving the shaft 2.

Fig. 3 shows an exemplary sectional structure of the swash plate 3. Fig. 3 is a schematic view showing a structure in a cross section perpendicular to the sliding surface with respect to the shoe 5. The swash plate 3 has a base material 31, a coating layer 32, and a coating layer 33. Both the coating 32 and the coating 33 slide on the slipper 5. Each of the coating layer 32 and the coating layer 33 is an example of a resin coating layer according to the present invention. The base material 31 has a disk shape with a hole in the center, and is formed of a metal satisfying the required characteristics, such as an iron-based alloy, a copper-based alloy, or an aluminum-based alloy. In order to prevent adhesion with the shoe 5, it is preferable that the base material 31 be formed of a material different from that of the shoe 5.

The coating layer 32 is provided to improve the characteristics of the sliding surface of the swash plate 3. The coating 32 includes at least a binder resin. In this regard, the coating 32 is an example of a resin coating. The binder resin is formed of, for example, a thermosetting resin. As the thermosetting resin, for example, at least one of polyamide imide (PAI), Polyamide (PA), Polyimide (PI), epoxy resin, polyether ether ketone (PEEK), and phenol resin is used. The coating 32 may include a solid lubricant as an additive. Adding a solid lubricant to improve lubrication characteristics; i.e. to reduce the friction coefficient. The coating 32 comprises, for example, 20 to 70 volume percent of a solid lubricant. As the solid lubricant, for example, at least one of MoS2, graphite (Gr), carbon, fluorine-based resin (polytetrafluoroethylene (PTFE) or the like), soft metal (Sn, Bi or the like), WS2, and h-BN is used. The coating 32 may include hard particles as an additive. As the hard particles, for example, at least one of an oxide, a nitride, a carbide, and a sulfide is used.

In order to prevent abrasion of the coating layer 32, the thickness of the coating layer 32 is preferably 10 μm or more, more preferably 15 μm or more, and still more preferably 20 μm or more. For example, if the thickness of the coating 32 is less than 5 μm, the coating 32 may be abraded to expose the base material 31. When the base material 31 is exposed, there arises a problem that the friction coefficient increases or the base material 31 adheres to the shoe 5. Further, since there is a possibility that seizure resistance may be reduced when the film of the coating layer 32 is too thick, it is preferable that the thickness is 50 μm or less. The material and thickness of the coating 33 is the same as the coating 32.

Fig. 4 shows an exemplary surface shape of the base material 31. A plurality of grooves 312 are formed on the surface 311 of the substrate 31. The surface 311 is a surface facing the shoe 5 as an example of the fitting member. The groove 312 is formed in the sliding direction with respect to the shoe 5. In this example, the groove 312 has a shape extending radially from the center of the hole 39 as viewed from a position shifted from the center of the hole 39 in a direction perpendicular to the surface 311. The groove 312 is an example of a groove extending in a direction intersecting the sliding direction of the mating member over the entire circumference of the ring shape of the base material 31.

Fig. 5 shows an exemplary shape of the groove 312. Fig. 5 is a schematic view of the groove 312 as viewed from a direction perpendicular to the surface 311. In this example, the groove 312 is formed by laser machining. Laser processing refers to a processing technique that utilizes laser energy. Specifically, the groove 312 is formed by moving the irradiation position while the base material 31 is treated with the laser beam pulse. One pulse of laser irradiation melts and scatters a portion of the base material 31, thereby forming a substantially circular recess (or hole). By concentrically moving the irradiation position, the concentric groove 312 is formed. The plurality of grooves 312 have a substantially arc shape in a cross section perpendicular to the sliding direction. The interval p1 between the bottoms of adjacent grooves 312 is, for example, 10 μm to 100 μm, and the width w1 of the opening of the groove 312 is, for example, 10 μm to 100 μm. In this example, the spacing p1 and the width w1 are approximately equal. In one example, the spacing p1 is between 40 μm and 80 μm. The spacing p1 may be greater than the width w 1. In a cross section parallel to the sliding direction, the groove 312 is not flat but has minute irregularities caused by the spot of the laser beam. In one example, the spacing p2 between the concave and convex surfaces is 10 μm to 30 μm.

Fig. 6 shows an exemplary surface shape of the coating 32. The surface 321 of the coating 32 becomes a sliding surface that slides with the shoe 5. A plurality of grooves 322 are formed in surface 321. In this example, the grooves 322 have the shape of concentric circles having a common center with the hole 39 when viewed from a position shifted from the center Cs of the hole 39 in a direction perpendicular to the surface 321. Among the plurality of grooves 322, each distance p2 between the bottoms of adjacent grooves 322 and each width w2 of the grooves 322 are substantially the same as the distance p1 and the width w1, respectively. The spacing p2 and width w2 may be different from the spacing p1 and width w 1.

Here, the problems to be solved by the present invention will be described in detail. The inventors of the present application have made efforts to replace the roughening treatment of the surface 311 of the base material 31, which has been conventionally performed by shot blasting, by laser processing. First, a prototype of substrate 31 having concentric grooves with centers common to the centers of holes 39 on surface 311 was made. When the swash plate having the resin coating layer formed on the base material 31 was subjected to the wear test, the inventors found that abnormal wear occurred.

Fig. 7 illustrates abnormal wear. Fig. 7 (a) shows normal wear and tear, and fig. 7 (B) shows abnormal wear. In normal wear, the sliding surface after use is substantially flat. On the other hand, in the abnormal wear, the surface of the coating layer 32 is worn following the groove formed in the surface 311 of the base material 31. That is, in the coating layer 32, the portion corresponding to the groove is worn deeper than the other portions. Due to this uneven wear, a convex surface (or a groove) following the groove formed in the surface 311 of the base material 31 is formed on the sliding surface after use.

To avoid accidental failure, it is desirable to reduce this uneven wear. The inventors of the present application made the following assumptions about the cause of occurrence of uneven wear. In the example using the base material 31 having the concentric grooves, since the coating layer 32 has few irregularities in the sliding direction, the influence of the force opposing the shear force generated in the sliding direction is small. Therefore, the wear tends to advance in a direction along the groove (i.e., in the sliding direction). Based on this assumption, the inventors of the present application conceived a surface structure in which a force opposing a shear force generated in the sliding direction easily acts.

2. Manufacturing method

Fig. 8 shows an exemplary flow chart illustrating a method of manufacturing the swash plate 3. In step S1, the base material 31 is prepared. The preparation of the substrate 31 includes, for example, the polishing of the surface and the cleaning using a cleaning liquid. In step S2, a groove 312 is formed in the surface 311 of the base material 31. The groove 312 is formed by, for example, laser machining. In step S3, the surface 311 is cleaned. This washing is performed, for example, by air blowing, without using a washing liquid such as ethanol. In step S4, the precursor material of the coating 32 is applied to the substrate 31. For example, the application of the precursor material is performed by roll coating or pad printing. In step S5, the coating 32 is dried and fired. In step S6, a groove 322 is formed in the surface 321 of the coating 32. The groove 322 is formed, for example, by cutting.

3. Examples of the embodiments

(1) Sample preparation

Fig. 9 shows the surface shape of the base material 31 in the examples and comparative examples. In the comparative example (a of fig. 9), the concentric groove 312 is formed by laser processing. The distance between the concave portions formed by pulse irradiation of the laser beam in the traveling direction of the machining process (in this case, the traveling direction is substantially equal to the sliding direction) is 10 μm to 30 μm, and the distance between the concave portions formed in the direction perpendicular to the traveling direction is 40 μm to 80 μm. The surface roughness after machining was about 8RzJIS along the advancing direction of machining. In the example (B of fig. 9), the radial groove 312 is formed by laser processing. The surface roughness after processing was about 6 RzJIS.

A resin coating layer is formed on the base material 31 subjected to the above surface treatment. PAI was used as the binder resin, and MoS2 and graphite were used as the solid lubricant.

(2) Abrasion test

The wear test was performed under the following conditions called poor lubrication conditions.

The lubricating method comprises the following steps: oil mist injection

Lubrication: 0.22mg/min

Peripheral speed: 4.2m/s

Surface pressure: 3.2MPa

And (3) testing time: 20 minutes

Atmosphere: atmosphere (es)

(3) Test results

Fig. 10 shows the surface state of the resin coating layer after the abrasion test. Fig. 10 (a) shows the results of the example, and fig. 10 (B) shows the results of the comparative example. In the comparative example, grooves having a depth of about 2 μm to 3 μm were present on the surface of the sample (sliding surface) at the same intervals as the grooves 312 on the base material 31 in the direction perpendicular to the sliding direction. That is, uneven wear occurs. On the other hand, in the examples, the surface of the sample was almost flat (about 0.3 μm ra) without any grooves. Thus, according to the present embodiment, uneven wear can be suppressed.

In addition to suppressing uneven wear of the resin coating, the swash plate according to the embodiment can simplify the roughening step and the subsequent cleaning step compared to the example in which the surface 311 of the base material 31 is roughened using shot blasting.

4. Modifying

The present invention is not limited to the above-described embodiments, and various modifications may be applied. Several variations are described below. Two or more items in the following modifications may be combined.

The shape of the groove 322 is not limited to the example shown in the embodiment. For example, the grooves 322 may have other shapes, such as concentric circles, spirals, or a grid.

The base material 31 is not limited to being formed of a single material. For example, a two-layer structure in which a copper alloy lining layer is formed on a steel backing metal, or a structure having three or more layers may be used.

Description of the reference numerals

1.. compressor, 2.. shaft, 3.. swash plate, 4.. piston, 5.. slipper, 31.. base material, 32.. coating, 33.. coating, 39.. bore, 311.. surface, 312.. groove, 321.. surface, 322.. groove

Claims

1. A swash plate, comprising:

a substrate having a ring shape, the substrate including a surface facing the mating member;

a plurality of grooves extending in a direction intersecting with a sliding direction of the engaging member over an entire circumference of the ring shape on the surface; and

a resin coating layer formed on the surface and forming a sliding surface with the mating member.

2. The swash plate of claim 1,

the plurality of grooves extend radially from a center of the ring shape.

3. The swash plate according to claim 1 or 2,

among the plurality of grooves, a distance between adjacent grooves is 20 to 240 μm.

4. The swash plate according to any one of claims 1 to 3,

the roughness of the surface is 5 μm RzJIS to 15 μm RzJIS.