Sliding parts and fluid machinery

Abstract

The present invention provides a sliding component having excellent wear resistance. To solve this problem, a sliding component (12) in contact with a sliding surface (13) is provided. The sliding component (12) includes: a first component (12a) composed of a first material, the first material containing a first matrix resin composed of a resin other than a fluororesin, and fluororesin particles and rod-shaped particles dispersed in the first matrix resin; and a second component (12b) arranged adjacent to the first component (12a) along the sliding surface (13) and composed of a second material containing a second matrix resin composed of a fluororesin and a reinforcing agent dispersed in the second matrix resin.

Description

Technical Field

[0001] The present invention relates to a sliding component and a fluid machine. Background Art

[0002] As a fluid machine that can compress or expand gas, for example, a reciprocating fluid machine (gas compressor, etc.) is known. Reciprocating fluid machines include ordinary piston-type fluid machines and swinging piston-type fluid machines. The former fluid machine has a bearing at the compression and expansion chamber side end of the connecting rod, and has a piston supported by the bearing in a swinging manner. The latter fluid machine does not have a bearing on the compression and expansion chamber side of the connecting rod, but has a piston that is integrated with the connecting rod. Among them, in the swinging piston-type fluid machine, the gas is compressed by the piston swinging and reciprocating in a metal cylinder. The piston has a sliding part that slides on the inner circumference of the cylinder. As the sliding part, for example, a lip ring, a piston ring, etc. can be cited.

[0003] As a related technology for sliding components, Patent Document 1 describes a "piston for an air cylinder, characterized in that, in an air cylinder device comprising an air cylinder and a piston engaged with the inner circumferential surface of the cylinder via a piston ring, the piston ring is formed on the outer circumference of the piston by insert molding using a resin composition containing as essential components 60 to 80% by weight of polyphenylene sulfide (PPS) resin, 10 to 30% by weight of fluororesin, 2 to 10% by weight of spherical filler, and 2 to 10% by weight of fibrous filler."

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 3-74681 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] The technology described in Patent Document 1 still has room for improvement in terms of wear resistance of sliding parts, and the details will be described later with reference to examples.

[0009] The problem to be solved by the present invention is to provide a sliding component and a fluid machine having excellent wear resistance.

[0010] Technical solutions to solve problems

[0011] The sliding component of the present invention is a sliding component that contacts a sliding surface and is characterized by comprising: a first component composed of a first material containing a first matrix resin composed of a resin other than fluororesin, and fluororesin particles and rod-shaped particles dispersed in the first matrix resin; and a second component disposed adjacent to the first component and composed of a second material containing a second matrix resin composed of fluororesin and a reinforcing agent dispersed in the second matrix resin. Other solutions will be described in the detailed embodiments below.

[0012] Effects of the Invention

[0013] According to the present invention, a sliding component and a fluid machine having excellent wear resistance can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing the sliding member according to the first embodiment.

[0015] Figure 2 is a cross-sectional view of the first component.

[0016] Figure 3 is a cross-sectional view of the second component.

[0017] Figure 4 This is a diagram illustrating a transfer film formed during sliding.

[0018] Figure 5 It is a schematic diagram of a fluid machine including the sliding member according to the first embodiment.

[0019] Figure 6 It is a cross-sectional view showing a sliding member according to a second embodiment.

[0020] Figure 7 This is a diagram explaining the test method of the friction test.

[0021] Figure 8 This is an energy dispersive X-ray analysis image of the test piece surface after the friction test.

[0022] Figure 9 It is a graph showing the test results of the wear amount and friction coefficient obtained from the friction test.

[0023] Figure 10 This is a graph showing the correlation between the wear amount and friction coefficient obtained from the friction test and the content of the fluororesin particles. DETAILED DESCRIPTION

[0024] Hereinafter, the manner of implementing the present invention (referred to as an embodiment) will be described with reference to the accompanying drawings. In the description of the following embodiment, descriptions of other embodiments that can be applied to one embodiment are also appropriately made. The present invention is not limited to the following embodiment, and different embodiments can be combined with each other, or can be arbitrarily deformed within the scope that does not significantly damage the effect of the present invention. In addition, the same symbols are marked on the same parts, and repeated descriptions are omitted. In addition, the parts with the same functions are marked with the same names. The contents of the drawings are merely schematic. For the convenience of illustration, sometimes the actual structure is changed within the scope that does not significantly damage the effect of the present invention, or the illustration of some parts is omitted or deformed between the drawings.

[0025] Figure 1 1 is a cross-sectional view showing a sliding member 12 of the first embodiment. The sliding member 12 is a member that contacts the inner wall surface of the metal member 11, i.e., the sliding surface 13. In the example shown in the figure, the sliding member 12 performs reciprocating motion (up and down motion) as indicated by the solid arrow while sliding on the sliding surface 13. The sliding member 12 is configured as a piston 40 ( Figure 5 The sliding member 12 includes a first member 12a and a second member 12b.

[0026] Figure 2 This is a cross-sectional view of first component 12a. First component 12a is made of a first material, which includes a first matrix resin 21 made of a resin other than fluororesin, and fluororesin particles 22 and rod-shaped particles 23 dispersed in first matrix resin 21. Fluororesin particles 22 and rod-shaped particles 23 are preferably dispersed throughout first matrix resin 21, but may be locally dispersed.

[0027] The first matrix resin 21 forms the outer contour of the first component 12a. The first matrix resin 21 is made of a resin other than a fluororesin and is not particularly limited as long as it can function as the sliding component 12. Among them, resins with excellent heat resistance and a low thermal expansion coefficient are preferred. Specifically, examples include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), polyethersulfone (PES), phenolic resin (PF), polyimide (PI), and their modified forms. The first matrix resin 21 can be used alone or in any combination of two or more.

[0028] The first matrix resin 21 preferably contains at least one of polyphenylene sulfide and polyetheretherketone. By containing these polymers, the heat resistance of the first member 12a can be improved.

[0029] Fluorine resin particles 22 on the sliding surface 13 ( Figure 1 ) when sliding on the sliding surface 13, a transfer film 14 ( Figure 4The constituent material of the fluororesin particles 22 is not particularly limited as long as it is a fluororesin. Examples thereof include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), and polyvinylidene fluoride (PVDF). The constituent material of the fluororesin particles 22 may be used alone or in any combination of two or more.

[0030] The fluororesin particles 22 preferably contain at least one of polytetrafluoroethylene or tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. By using these polymers, the fluororesin particles 22 can promote the Figure 1 ) is formed on a transfer film 14.

[0031] The form of the fluororesin particles 22 is not particularly limited as long as it does not significantly impair the effects of the present invention. For example, the particles can be in a granular (particulate) form. The particle size can be, for example, from 5 μm to 200 μm. The particle size can be measured, for example, as an average particle size that can be measured using a laser diffraction particle size distribution analyzer.

[0032] The content of the fluororesin particles 22 is not particularly limited as long as it does not significantly impair the effects of the present invention, but is preferably 15% by mass or more and 30% by mass or less relative to the first material. By keeping the content within this range, the excessive thermal expansion of the first member 12a caused by the fluororesin particles 22 can be suppressed, and the contact between the first member 12a and the sliding surface 13 ( Figure 1 ) friction coefficient. Furthermore, it is possible to suppress the transfer film 14 ( Figure 4 ) is peeled off. Thus, the wear resistance of the sliding component 12 can be particularly improved.

[0033] The rod-shaped particles 23 enhance the strength of the first component 12a against stresses such as tensile stress due to their rod-like shape. While the rod-shaped particles 23 can be made of any material without significantly impairing the effects of the present invention, they preferably contain at least one of carbon fibers or glass fibers. By using these fibers, the rod-shaped particles 23 can be constructed using readily available fibers.

[0034] The length and diameter of the rod-shaped particles 23 are not particularly limited as long as they do not significantly impair the effects of the present invention. For example, the length can be set to be between 10 μm and 300 μm, and the diameter can be set to be between 1 μm and 30 μm. The length and diameter can be measured using a microscopic photograph of a cross section of the first member 12 a.

[0035] The content of the rod-shaped particles 23 is not particularly limited as long as the effects of the present invention are not significantly impaired, and may be, for example, 5% by mass or more and 20% by mass or less relative to the first material.

[0036] However, when the rod-shaped particles 23 contain carbon fibers, the carbon fiber content is preferably 5% to 15% by mass relative to the first material. This can improve the strength of the first member 12a against stress such as shear stress.

[0037] Figure 3 This is a cross-sectional view of the second component 12b. The second component 12b is made of a second material, which includes a second matrix resin 31 made of a fluororesin and a reinforcing agent 32 dispersed in the second matrix resin 31. The reinforcing agent 32 is preferably dispersed throughout the entire second matrix resin 31, but may be locally distributed.

[0038] The second matrix resin 31 forms the outer contour of the second component 12b. The second matrix resin 31 is not particularly limited as long as it is a fluororesin, as long as it does not significantly impair the effects of the present invention. For example, the fluororesin particles 22 ( Figure 2 The second matrix resin 31 may be used alone or in any combination of two or more.

[0039] The second matrix resin 31 preferably contains polytetrafluoroethylene. By containing polytetrafluoroethylene, it can be combined with the first component 12a ( Figure 2 ) in the fluororesin particles 22 ( Figure 2 ) together to promote the sliding surface 13 ( Figure 1 ) is formed on the transfer film 14 ( Figure 4 ).

[0040] The above-mentioned fluororesin particles 22 ( Figure 1 ) and the second matrix resin 31 are preferably made of the same type of fluororesin. In this way, the transfer film 14 of the same constituent material can be formed on the sliding surface 13 by the fluororesin particles 22 and the second matrix resin 31, which can promote transfer.

[0041] The reinforcing agent 32 improves the resistance of the second component 12b (particularly the second matrix resin 31) to stresses such as shear stress. The specific material of the reinforcing agent 32 is not particularly limited, provided that the effects of the present invention are not significantly impaired. The reinforcing agent 32 may be used singly or in any combination of two or more in any ratio.

[0042] The reinforcing agent 32 preferably contains at least one of copper, a copper alloy (an alloy having copper as its main component, such as bronze) or carbon fiber. By using these materials, even if the reinforcing agent 32 falls off from the second component 12b and enters the sliding surface 13, the sliding surface 13 can be prevented from being damaged due to the soft material.

[0043] The reinforcing agent 32 may be in any form without significantly impairing the effects of the present invention, and may be, for example, in a granular form. The particle size of the reinforcing agent 32 may be any form without significantly impairing the effects of the present invention.

[0044] The content of the reinforcing agent 32 is not particularly limited as long as the effects of the present invention are not significantly impaired, and may be, for example, 5% by mass or more and 30% by mass or less relative to the second material.

[0045] The second material preferably further contains a solid lubricant 33. By containing the solid lubricant, the sliding surface 13 ( Figure 1 ) forms a lubricating film (not shown) on the second component 12b, thereby reducing the friction between the second component 12b and the sliding surface 13, and further improving the wear resistance of the sliding component 12. The solid lubricant 33 can be used alone or in any ratio and combination of two or more.

[0046] The solid lubricant 33 preferably contains at least one of molybdenum disulfide or spherical carbon. The inclusion of at least one of these can reduce friction between the second member 12b and the sliding surface 13, improve wear resistance, and enhance the resistance of the second member 12b to stresses such as shear stress. For example, molybdenum disulfide exhibits solid lubricity due to weak S-S bonds, causing interlayer delamination.

[0047] The content of the solid lubricant 33 is not particularly limited as long as the effects of the present invention are not significantly impaired, and may be, for example, 1% by mass or more and 15% by mass or less relative to the second material.

[0048] Return to Figure 1 , the second component 12b is arranged adjacent to the first component 12a along the sliding surface 13. "Adjacent" here means that the first component 12a and the second component 12b do not necessarily need to be in contact with each other in the direction of the sliding surface 13 (the sliding direction). Any component can be arranged between the first component 12a and the second component 12b within a range that does not significantly impair the effects of the present invention. In the example shown in the figure, the first component 12a and the second component 12b are in contact with each other in the direction of the sliding surface 13. The first component 12a and the second component 12b are arranged continuously along the sliding surface 13 in the circumferential direction of the sliding component 12.

[0049] The first component 12a and the second component 12b are arranged in a manner such that the second component 12b is sandwiched between at least two first components 12a. Figure 3) thermal expansion occurs, because the first component 12a clamps the second component 12b, the deformation of the entire sliding component 12 caused by thermal expansion can be kept within the design allowable range. In addition, the transfer film 14 ( Figure 4 ), it is possible to improve the wear resistance of the sliding member 12. In addition, in the illustrated example, two first members 12a are provided. However, when three or more first members 12a are provided, the second member 12b may be disposed between any two first members 12a.

[0050] Figure 4 This figure explains the transfer film 14 formed during sliding. When the sliding member 12 slides on the sliding surface 13, the transfer film 14 made of fluororesin is formed on the sliding surface 13.

[0051] The fluororesin particles 22 ( Figure 2 ) and the second matrix resin 31 ( Figure 3 ) has a relatively large thermal expansion coefficient of fluororesin. Therefore, if the sliding member 12 is composed of only the first member 12a or only the second member 12b, deformation and uneven wear may occur, especially in a high-temperature friction environment. Specific examples of high-temperature friction environments include fluid machinery 100 (such as a reciprocating gas compressor of an oscillating piston type) Figure 5 ) in the compression expansion chamber 44 ( Figure 5 ) etc.

[0052] Therefore, the first matrix resin 21 ( Figure 2 The sliding member 12 is composed of a first member 12a having a first matrix resin 31 and a second member 12b having a second matrix resin 31 made of a fluororesin. The first matrix resin 21, which is made of a resin other than a fluororesin, has a high coefficient of friction due to its constituent material, and the transfer film 14 formed on the sliding surface 13 is peeled off by the second matrix resin 31. Therefore, by dispersing the fluororesin particles 22 in the first matrix resin 21, the coefficient of friction of the first member 12a on the sliding surface 13 can be reduced, peeling of the transfer film 14 can be suppressed, and wear resistance can be improved.

[0053] On the other hand, when only the first member 12a is used, the fluororesin that forms the transfer film 14 is derived solely from the fluororesin particles 22, so there is still room for improvement in the degree of formation of the transfer film 14. Therefore, by using the second member 12b having the second matrix resin 31 composed of fluororesin in addition to the first member 12a, the formation of the transfer film 14 can be accelerated, thereby achieving a reduction in the friction coefficient and an improvement in wear resistance.

[0054] In addition, in the sliding member 12, the first member 12a and the second member 12b assist each other in forming the transfer film 14 ( Figure 4 ) to achieve wear suppression. In addition, the first matrix resin 21 and the second matrix resin 31 respectively contain materials other than fluororesin (rod-shaped particles 23 ( Figure 2 ), Enhancer 32( Figure 3 ) and solid lubricant 33( Figure 3 )), toughness or lubricity is improved. Thus, the wear resistance of the first component 12a and the second component 12b can be improved.

[0055] Furthermore, in the sliding member 12, the first material, the second material, the fluororesin particles 22 ( Figure 2 The presence of the rod-shaped particles 23, the reinforcing agent 32, and the solid lubricant 33 can be easily confirmed, for example, by performing surface observation and chemical analysis such as optical microscopy, energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy, and infrared spectroscopy on the surface or a crushed product of the first member 12a or the second member 12b.

[0056] Return to Figure 1 The metal component 11 may be composed of, for example, transition metals such as iron, nickel, molybdenum, chromium, titanium, and copper, or light metals such as aluminum, silicon, and magnesium. Specifically, the metal component 11 may be composed of, for example, aluminum, aluminum alloys, and other aluminum-based materials; copper, copper alloys, and other copper-based materials; titanium, titanium alloys, and other titanium-based materials; and iron, iron-nickel alloys, and other iron-based materials.

[0057] The metal member 11 may be, for example, an untreated metal material, but it may also be surface-treated. In this case, the sliding member 12 slides in contact with the treated surface. Specifically, the surface of the metal member 11 may be formed from the metal element that constitutes the metal member 11, or it may be formed by a surface treatment applied to the metal member 11.

[0058] The surface treatment formed on the surface of the metal component 11 is, for example, a surface coating artificially applied to the metal material, a natural oxide film, or the like. For example, the natural oxide film is aluminum oxide when the metal component 11 is aluminum, and iron oxide when the metal component 11 is iron. The surface coating is formed, for example, by chemical vapor deposition (CVD), physical vapor deposition (PVD), electroplating, carburizing, or the like, and is composed of a material containing at least one of aluminum, chromium, iron, phosphorus, nickel, and zinc. Specifically, examples include anodized aluminum, aluminum plating, chromium plating, iron plating, nickel plating, and zinc plating.

[0059] Figure 5Schematic diagram of a fluid machine 100 having a sliding member 12 according to the first embodiment. In the example shown, the fluid machine 100 is a reciprocating gas compressor of an oscillating piston type. The fluid machine 100 has an inner wall surface 411 (sliding surface 13 ( Figure 1 ) one example) there is no sufficient lubricating oil etc. and when it is used in a less oil state, or when it is used in an oil-free state without lubricating oil at all, a particularly good effect is shown. However, lubricating oil, grease etc. may also be present on the inner wall surface 411.

[0060] The fluid machine 100 includes a cylinder 41 (metal component 11 ( Figure 1 ) and a piston 40 that reciprocates (in the example shown) within a cylinder 41. The piston 40 includes a sliding member 12 that slides on an inner wall surface 411 of the cylinder 41. The sliding member 12 is composed of a piston body 42 (a first member 12a ( Figure 1 ) and the piston ring 43 (the second member 12b ( Figure 1 The piston ring 43 is, for example, annular and is fitted into an annular groove (not shown) formed on the outer peripheral side surface of the disc-shaped piston main body 42.

[0061] The space above piston 40 in cylinder 41 contains a compression / expansion chamber 44, a working space for compressing or expanding gas. The upper end of cylinder 41 is sealed by a partition 45, which has an intake port 45a and an outlet port 45b. Intake port 45a and outlet 45b are each equipped with an intake valve 45c and an outlet valve 45d, respectively, and are connected to piping (not shown).

[0062] The working principle of gas compression will be described. The piston 40 and connecting rod 46 are integrally formed. As the piston 40 moves up and down in response to the rotation of the crankshaft 47, gas is drawn into the compression-expansion chamber 44 through the intake port 45a, where it is compressed. The compressed gas is discharged to the outside through the discharge port 45b and recovered via piping (not shown).

[0063] The piston 40 is a separate component from the connecting rod 46 that supports the piston 40. In the illustrated example, as the piston 40 moves up and down, the piston 40, which is formed by the sliding member 12, slides by making point contact with the inner wall surface 411 of the cylinder 41. The connecting rod 46 can be made of metal or resin.

[0064] The inner wall surface 411 of the cylinder 41 may be coated by surface treatment of the metal member 11. For example, a natural oxide film may be directly formed on the inner peripheral surface of the cylinder 41, or an anodic aluminum film may be formed. Alternatively, the inner peripheral surface of the cylinder 41 may not be coated.

[0065] In addition, the sliding member 12 can be used to Figure 5 In addition to the fluid machine 100 shown, the fluid machine can also be used in mechanical devices requiring good sliding properties, such as analysis equipment, vacuum equipment, and space-related equipment.

[0066] Figure 6 1 is a cross-sectional view showing a sliding member 121 according to the second embodiment. The sliding member 121 is similar to the sliding member 12 ( Figure 1 )same.

[0067] In the sliding member 121, the first member 12a and the second member 12b are arranged in such a manner that the first member 12a is sandwiched between at least two second members 12b. By such an arrangement, the transfer film 14 ( Figure 4 ), can promote the transfer film 14 ( Figure 4 ) formation.

[0068] Example

[0069] <Example 1>

[0070] The first matrix resin 21 ( Figure 2 ), containing PTFE as fluororesin particles 22 ( Figure 2 ) and contains carbon fibers as rod-shaped particles 23 ( Figure 2 ) of the first material to make the first component 12a ( Figure 2 Fluororesin particles 22 and rod-shaped particles 23 are dispersed throughout the first matrix resin 21. The content of fluororesin particles 22 is 15% by mass relative to the first matrix resin. Furthermore, the content of rod-shaped particles 23 is 10% by mass relative to the first matrix resin. The length and diameter of rod-shaped particles 23 are expressed as the average length and diameter measured by the above method: 100 μm in length and 8 μm in diameter.

[0071] The second matrix resin 31 (containing PTFE) Figure 3 ), containing bronze as a reinforcing agent 32( Figure 3 ), containing molybdenum disulfide and spherical carbon as solid lubricants 33 ( Figure 3 ) of the second material to make the second component 12b ( Figure 3 ). The reinforcing agent 32 and the solid lubricant 33 are dispersed throughout the second matrix resin 31. The content of the reinforcing agent 32 is 10% by mass relative to the second material. Furthermore, the content of molybdenum disulfide is 5% by mass relative to the second material. The content of the spherical carbon is 10% by mass relative to the second material. Therefore, in Example 1, the total usage of the solid lubricant 33 composed of molybdenum disulfide and spherical carbon is 15% by mass relative to the second material.

[0072] Figure 7 This is a diagram illustrating the test method of the friction test. The sliding component 12 of Example 1 is manufactured in such a manner that the manufactured first component 12a and the second component 12b are arranged on the sliding surface 13. The sliding component 12 is manufactured in such a manner that the first component 12a surrounds the second component 12b. The height H1 of the first component 12a in the vertical direction of the paper is 10 mm, and the width W1 in the horizontal direction of the paper is 10 mm. The height H2 of the second component 12b in the vertical direction of the paper is 5 mm, and the width W2 in the horizontal direction of the paper is 4 mm. The lengths of the first component 12a and the second component 12b in the depth direction of the front of the paper (not shown) are both shorter than the longitudinal length of the test piece 15 described later. The area ratio of the first component 12a and the second component 12b on the sliding surface 13 is 6:4.

[0073] The sliding component 12 is brought into contact with a test piece 15 composed of an aluminum alloy plate (longitudinal (depth direction from the front of the paper, not shown) 20 mm, transverse W3 43 mm, thickness H3 3 mm) which is an anodized aluminum film treated surface serving as the sliding surface 13, and is reciprocated in the left and right directions of the paper. As conditions for the friction test, the contact surface pressure between the sliding component 12 and the test piece 15 is set to 3 MPa, the friction speed is set to 0.4 m / s, the distance of one reciprocating motion is set to 20 mm, and the surface temperature of the test piece 15 (the temperature of the sliding surface 13) is set to 110°C. In addition, in the friction test, the total amount of wear during sliding for a specified time and the friction coefficient during sliding for a specified time are measured. The results of the friction test will be referred to later. Figures 8 to 10 Provide explanation.

[0074] <Comparative Example 1>

[0075] In addition to not containing fluororesin particles 22 ( Figure 2 ) and rod-shaped particles 23 ( Figure 2 ) Except for the above, the other operations were carried out in the same manner as in Example 1 to produce a sliding component of Comparative Example 1 and conduct a friction test. The results of the friction test will be referred to later. Figures 8 to 10 Explanation

[0076] Comparative Example 2

[0077] The sliding member of Comparative Example 2 was manufactured in the same manner as in Example 1 except that the second member 12b was not provided, and a friction test was performed. The results of the friction test will be referred to later. Figures 8 to 10 Here, the sliding member of Comparative Example 2 corresponds to the technology described in Patent Document 1 above.

[0078] Table 1 below shows the constituent materials of the sliding components of Example 1, Comparative Example 1, and Comparative Example 2. "∘" indicates that the components were used, and "-" indicates that the components were not used.

[0079] [Table 1]

[0080]

[0081] Figure 8 This is an energy dispersive X-ray analysis image (EDX) of the test piece surface after the friction test. The EDX-Al image shows the presence of aluminum on the test piece surface, and the EDF-F image shows the presence of fluorine on the test piece surface. In the EDX-Al image of Example 1, there is almost no white portion, which shows that there is no aluminum on the surface. On the other hand, in the EDX-F image of Example 1, there is a white portion, which shows that there is fluorine on the surface. Therefore, a fluorine-containing transfer film 14 ( Figure 4 ), therefore, it can be considered that aluminum, the constituent material of the test piece, was hardly detected.

[0082] On the other hand, the EDX-Al images of Comparative Examples 1 and 2 show white portions, indicating the presence of aluminum on the surface of the test piece. On the other hand, the EDX-F images of Comparative Examples 1 and 2 show no white portions, indicating the absence of fluorine on the surface. Therefore, it can be considered that the fluorine-containing transfer film 14 ( Figure 4 ), most of the aluminum constituting material of the test piece is directly exposed.

[0083] These results can be considered to be the result of both the first component 12a and the second component 12b containing fluororesin. In other words, it is believed that the transfer film 14 can be formed by including the first component 12a and the second component 12b, as in the sliding component 12 of the present invention. However, as in Comparative Example 1, for example, when the fluororesin particles 22 are not used, the transfer film 14 formed by the second component 12b is peeled off by the first component 12a, as described above, resulting in the transfer film 14 being unlikely to remain. Furthermore, as shown in Comparative Example 2, the lack of the second matrix resin 31, which is a fluororesin, makes the formation of the transfer film 14 difficult, and there is room for improvement in the degree of formation of the transfer film 14.

[0084] Figure 9 It is a graph showing the test results of the wear amount (bar graph) and the friction coefficient (point graph) obtained by the friction test. Figure 9 Indicates Figure 7 The total wear amount when sliding for a predetermined time in the friction test shown is the average value of the friction coefficient during the predetermined time. However, in order to facilitate understanding of the results, the wear amount is expressed as a relative value when Comparative Example 2 is 100.

[0085] The friction coefficient of Example 1 is lower than that of Comparative Examples 1 and 2. This is considered to be due to the Figure 8 As described above, a transfer film 14 ( Figure 4) is caused. Moreover, it is believed that due to the reduction in the friction coefficient, the sliding member 12 becomes easy to slide and the wear amount is reduced. Therefore, in the sliding member 12 of the present invention, excellent wear resistance is exhibited.

[0086] On the other hand, when comparing Example 1 with Comparative Examples 1 and 2, the wear and friction coefficients of Comparative Examples 1 and 2 were both higher than those of Example 1. This is presumably because, in Comparative Example 1, which did not contain the fluororesin particles 22, even though the transfer film 14 was formed, it was peeled off by the first member 12a, resulting in a higher wear and friction coefficient. Furthermore, in Comparative Example 2, which did not contain the second member 12b, it was believed that the transfer film 14 was inherently difficult to form, resulting in a higher wear and friction coefficient.

[0087] In addition, regarding Comparative Examples 1 and 2, if the friction coefficient is reduced, the sliding property is improved. However, for example, when the strength of the material to shear stress, etc. is reduced, excessive thermal expansion, etc., for example, occurs at the same time, the resulting wear amount increases. Therefore, the wear coefficient is a factor for reducing the wear amount, and only reducing the friction coefficient does not necessarily reduce the wear amount. Therefore, it can be considered that although the friction coefficient is smaller in Comparative Example 2, the wear amount is greater in Comparative Example 2. Therefore, it can be considered that in Example 1, the friction coefficient can be reduced to facilitate sliding, and the first component 12a and the second component 12b (both refer to Figure 7 ) such as reduced strength and excessive thermal expansion, so the amount of wear can be reduced.

[0088] Figure 10 The wear amount (circle icon) and friction coefficient (diamond icon) obtained from the friction test are compared with the fluororesin particles 22 ( Figure 2 ) content. Figure 10 The results shown are obtained by simulation Figure 7 The wear amount is expressed as a relative value when the content of the fluororesin particles 22 (PTFE) relative to the first material is 70% by mass, which is 100%.

[0089] The wear loss is particularly low when the content is within the range of 15% to 30% by mass. Therefore, when the content is within this range, particularly high wear resistance is exhibited. On the other hand, when the content is less than 15% by mass or exceeds 30% by mass, the wear loss tends to increase.

[0090] The friction coefficient shows a substantially constant value when the content is 15% by mass or more. Thus, it can be said that if the content is 15% by mass or more, a transfer film 14 ( Figure 4 ). Therefore, according to Figure 10The results show that the content of the fluororesin particles 22 is preferably 15% by mass or more and 30% by mass or less relative to the first material.

[0091] As described above, by applying the sliding member 12 of the present invention to the piston 40, which is a sliding portion of an oscillating piston type in a reciprocating gas compressor, for example, the wear resistance of the piston 40 can be improved. This can extend the life of the piston 40, for example, extending the maintenance cycle of the reciprocating gas compressor.

[0092] Description of Reference Numerals

[0093] 100: Fluid machinery; 11: Metal component; 12: Sliding component; 12a: First component; 12b: Second component; 13: Sliding surface; 14: Transfer film; 15: Test piece; 21: First base material resin; 22: Fluororesin particles; 23: Rod-shaped particles; 31: Second base material resin; 32: Reinforcement agent; 33: Solid lubricant; 40: Piston; 41: Cylinder; 411: Inner wall surface; 42: Piston body; 43: Piston ring; 44: Compression-expansion chamber; 45: Partition; 45a: Inlet port; 45b: Discharge port; 45c: Inlet valve; 45d: Discharge valve; 46: Connecting rod; 47: Crankshaft.

Claims

1. A sliding component that contacts a sliding surface, characterized in that: The sliding component includes: a first member composed of a first material including a first matrix resin composed of a resin other than a fluororesin, and fluororesin particles and rod-shaped particles dispersed in the first matrix resin; and a second member disposed adjacent to the first member along the sliding surface and composed of a second material containing a second matrix resin composed of a fluororesin and a reinforcing agent dispersed in the second matrix resin; The first component and the second component are arranged in a manner that the second component is sandwiched between at least two of the first components, or in a manner that the first component is sandwiched between at least two of the second components. The content of the fluororesin particles is 15% by mass or more and 30% by mass or less relative to the first material.

2. The sliding component according to claim 1, wherein The first matrix resin contains at least one of polyphenylene sulfide and polyetheretherketone.

3. The sliding component according to claim 1 or 2, characterized in that: The fluororesin particles contain at least one of polytetrafluoroethylene and a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.

4. The sliding component according to claim 1 or 2, characterized in that: The rod-shaped particles contain at least one of carbon fibers or glass fibers.

5. The sliding component according to claim 1 or 2, characterized in that: The second matrix resin contains polytetrafluoroethylene.

6. The sliding component according to claim 1 or 2, characterized in that: The reinforcing agent contains at least one of copper, copper alloy or carbon fiber.

7. The sliding component according to claim 1 or 2, characterized in that: The second material further contains a solid lubricant.

8. The sliding component according to claim 7, wherein: The solid lubricant contains at least one of molybdenum disulfide or spherical carbon.

9. The sliding component according to claim 1 or 2, characterized in that: The fluororesin particles and the second matrix resin are made of the same type of fluororesin.

10. The sliding component according to claim 1 or 2, characterized in that: The rod-shaped particles contain carbon fibers, The content of the carbon fibers is 5% by mass or more and 15% by mass or less relative to the first material.

11. A fluid machine, characterized in that: include: cylinder; and a piston having a sliding member that slides on the inner wall surface of the cylinder, The sliding component includes: a first member composed of a first material including a first matrix resin composed of a resin other than a fluororesin, and fluororesin particles and rod-shaped particles dispersed in the first matrix resin; and a second member disposed adjacent to the first member along the inner wall surface and composed of a second material containing a second matrix resin composed of a fluororesin and a reinforcing agent dispersed in the second matrix resin; The first component and the second component are arranged in a manner that the second component is sandwiched between at least two of the first components, or in a manner that the first component is sandwiched between at least two of the second components. The content of the fluororesin particles is 15% by mass or more and 30% by mass or less relative to the first material.

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