JP6628499B2 - Sliding member and pump - Google Patents

Description

  The present invention relates to a sliding member used for a pump or the like, for example, and more particularly to a sliding member used for a shaft / bearing structure having a shaft and a bearing, which slides relatively to a member to be slid. As a kind of a pump or the like to which the sliding member is applied, there is a preparatory standby operation pump capable of performing a full-speed operation (advance standby operation) in advance in an anhydrous state, and performing drainage in a gas-water mixed state.

  A shaft / bearing structure applicable to a pump or the like is disclosed in Patent Documents 1 and 2, for example.

  Patent Literature 1 discloses a shaft / bearing structure including a shaft sleeve that is a sliding member and a bearing member that is a slidable member. The shaft sleeve has a multi-layer structure of a stainless steel base and a hard layer covering the base, and the hard layer is made of a cemented carbide metal containing cemented carbide particles in a base powder of a cobalt-based alloy. By doing so, the wear resistance is increased and the sliding resistance is reduced.

In Patent Document 2, a stainless steel is used as a base material of a sleeve that is a sliding member, and a sprayed film of a WC (tungsten carbide) -based or Cr ₂ C ₃ -based cemented carbide is formed on the surface of the base material. TiN on the sprayed _{coating, TiC, TiCN, SiC, Si} 3 N 4, the hard coating diamond or diamond-like carbon, or shaft-bearing structure coated with a hard film of SiC fine particles containing Ni-P plating is disclosed I have.

JP 2001-254726 A (released on September 21, 2001) JP-A-5-52222 (published March 2, 1993)

  However, the shaft sleeve described in Patent Literature 1 has a problem in that the coefficient of friction is high, vibration occurs during operation of the pump, and the temperature increases.

  Further, the sleeve described in Patent Literature 2 has a problem that the hard coating is cracked or peeled off because the thermal spray coating is deformed by a load.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sliding member having excellent slidability and load resistance.

  In order to solve the above problems, a sliding member according to the present invention is used for a shaft / bearing structure having a shaft and a bearing, and is a sliding member that slides relatively to a member to be slid. A base layer, a coating layer containing diamond-like carbon, which is in sliding contact with the sliding member, and an intermediate layer provided between the base and the coating layer and containing diamond particles and a base material. And

  According to the above configuration, by providing the rigid intermediate layer, the stress load on the coating layer can be reduced, and the load resistance can be improved. Further, the diamond particles are hard and have a high elastic modulus, and thus contribute to the improvement of the hardness of the intermediate layer. Further, by using diamond-like carbon having good slidability as the coating layer, slidability is also improved.

  Furthermore, in the sliding member according to the present invention, the thickness of the intermediate layer may be 30 μm to 120 μm.

  According to the above configuration, by setting the thickness of the intermediate layer to 30 μm or more, the rigidity of the intermediate layer can be increased, and thereby the peeling of the coating layer can be prevented.

  Furthermore, in the sliding member according to the present invention, a part of the diamond particles may be contact particles that are in contact with the coating layer.

  According to the above configuration, since the diamond particles and the diamond-like carbon have similar compositions, the contact strength between the intermediate layer and the coating layer is improved by the contact particles being in contact with the coating layer. Thereby, the occurrence of peeling at the boundary between the intermediate layer and the coating layer can be prevented.

  Further, in the sliding member according to the present invention, the intermediate layer may have a convex portion at an interface between the intermediate layer and the coating layer, and the convex portion may be made of the contact particles.

  According to the above configuration, the adhesion between the intermediate layer and the coating layer can be further improved.

  Further, in the sliding member according to the present invention, the interface between the intermediate layer and the coating layer is located on the same circumference around the axis of the shaft / bearing structure, and the contact particles are formed at the interface. It may be in contact with the coating layer.

  According to the above configuration, the interface between the intermediate layer and the coating layer is located on the same circumference around the axis of the shaft / bearing structure. Even if the flakes are peeled or abraded and the sliding surface reaches the intermediate layer, the aggressiveness against the slidable member is low, and the life of the shaft / bearing structure can be extended.

  Further, in the sliding member according to the present invention, a volume ratio of the diamond particles in the intermediate layer may be 30% to 70%.

  According to the above configuration, it is possible to provide a sliding member which is hard to peel off the coating layer and has excellent durability.

  Further, in the sliding member according to the present invention, the base material may be a nickel alloy, a cobalt alloy, a copper alloy, or an iron alloy.

  According to the above configuration, the nickel alloy and the cobalt alloy have low melting points and good workability. Further, nickel alloys and cobalt alloys have good adhesion to diamond and diamond-like carbon. Further, a copper alloy having a low melting point and excellent corrosion resistance, or a relatively inexpensive iron alloy can also be used.

  Further, in the sliding member according to the present invention, the intermediate layer is at least a position corresponding to an end of the surface of the slidable member facing the sliding member parallel to the axial direction of the shaft / bearing structure. May be provided.

  According to the above configuration, if the intermediate layer is provided at least at a position corresponding to the end (11a) of the slidable member having severe wear, the wear of the slide member can be reduced and the diamond can be reduced. The amount of particles used can be reduced. Therefore, a sliding member excellent in slidability and wear resistance can be provided at low cost.

  Further, in the sliding member according to the present invention, in the sliding member, a position corresponding to an end of a surface facing the sliding member parallel to the axial direction of the shaft / bearing structure in the intermediate member, The volume ratio of the diamond particles may be higher than the volume ratio at other positions.

  According to the above-described configuration, the stress resistance is large and the wear corresponding to the end of the slidable member is increased at a position corresponding to the end of the slidable member. By reducing the amount of diamond particles, the amount of diamond particles used can be reduced, and a sliding member having excellent wear resistance can be provided at low cost.

  Further, the sliding member according to the present invention may be used for a pump.

  According to the above configuration, it is possible to provide a pump including a sliding member having excellent slidability and load resistance.

  According to one embodiment of the present invention, a sliding member and a pump having excellent slidability and load resistance can be provided.

1 is a schematic cross-sectional view illustrating a cross section perpendicular to an axial direction of a shaft / bearing structure according to a first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view illustrating a cross section perpendicular to the axial direction of a shaft / bearing structure according to a second embodiment of the present invention. FIG. 3 is a view showing a state in which the shaft / bearing structure shown in FIG. 2 has been worn by use. (A) and (b) are cross-sectional schematic diagrams showing a cross section perpendicular to the axial direction of a shaft / bearing structure according to Embodiment 3 of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a cross section parallel to an axial direction of a shaft / bearing structure according to a fourth embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a cross section parallel to an axial direction of a shaft / bearing structure according to a fourth embodiment of the present invention.

[Embodiment 1]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<Structure of sliding member>
FIG. 1 is a schematic cross-sectional view showing a cross section perpendicular to the axial direction of a shaft / bearing structure 1A according to the present embodiment.

  As shown in FIG. 1, the shaft / bearing structure 1A includes a shaft member 10 as a sliding member used for a pump or the like, and a bearing member 11 as a slidable member. The shaft member 10 is a cylindrical shaft sleeve, and slides relative to the bearing member 11. The shaft member 10 is not limited to a shaft sleeve, and may be a shaft. On the other hand, the bearing member 11 has a cylindrical shape in which the shaft member 10 is housed, and supports the shaft member 10.

  The bearing member 11 is made of, for example, hard ceramics or cemented carbide, and is preferably made of ceramics or cermet. By using ceramics or cermet as the bearing member 11, the durability of the bearing member 11 is improved. It is preferable that the inner surface of the bearing member 11 has few surface irregularities. Specifically, the surface roughness Ra may be 1.0 μm or less. The surface of the bearing member 11 may be processed to form a sintered body or a film for reducing the friction coefficient or improving the wear resistance.

  As shown in FIG. 1, the shaft member 10 includes at least a cylindrical base 10a, an intermediate layer 10b formed on the outer surface of the base 10a, and a coating layer 10c formed on the outer surface of the intermediate layer 10b. Prepare.

  The base 10a is formed of a generally used material, for example, stainless steel such as SUS304 or SUS403, or a hard alloy such as a cobalt (Co) alloy or a nickel (Ni) alloy. Further, the surface roughness Ra of the base 10a is preferably 1.0 μm or less.

  The intermediate layer 10b is a composite material including diamond particles 10d as hard particles and a base material 10e, and the diamond particles 10d are dispersed and held in the base material 10e. The diamond particles 10d are diamond particles such as diamond single crystal particles and particles obtained by pulverizing a diamond sintered body. As the base material 10e, a nickel alloy, a cobalt alloy, a copper alloy, an iron alloy, or the like is preferable. This is because nickel alloys and cobalt alloys have low melting points and good workability. In addition, the nickel alloy and the cobalt alloy have good adhesion to diamond and diamond-like carbon (hereinafter referred to as DLC) used for the coating layer 10c described below. Further, a copper alloy having a low melting point and excellent corrosion resistance or a relatively inexpensive iron alloy may be used.

  The base material 10e preferably has a Young's modulus (elastic modulus) of 50 to 300 GPa. By using a material having a Young's modulus within this range as the base material 10e, it is possible to absorb the stress applied to the shaft member 10 at the time of manufacturing or to reduce the impact when the shaft member 10 is used. Can be.

  From the viewpoint of reactivity with the diamond particles 10d, those having a melting point of the base material 10e of 1100 ° C. or less are preferable.

  The thickness of the intermediate layer 10b is preferably from 30 μm to 120 μm, and more preferably from 50 μm to 100 μm. The thickness of the intermediate layer 10b is preferably thick to increase the rigidity, and if it is less than 30 μm, it will be deformed by a load. Conversely, if the thickness of the intermediate layer 10b exceeds 120 μm, no further effect can be obtained, and the cost increases.

  The average particle diameter of the diamond particles 10d is preferably 20 μm to 120 μm. If the average particle diameter of the diamond particles 10d is less than 20 μm, the deformation resistance and the shear strength of the intermediate layer 10b decrease, and it becomes impossible to obtain sufficient rigidity in the intermediate layer 10b. On the other hand, if the average particle diameter of the diamond particles 10d exceeds 120 μm, it exceeds the thickness of the intermediate layer 10b, and it is necessary to process the diamond particles 10d after the formation of the intermediate layer 10b, which results in unnecessary cost. . The average particle size is a value measured by a laser diffraction type particle size distribution measuring device (SALD-2100, manufactured by Shimadzu Corporation).

  Furthermore, the volume ratio of the diamond particles 10d in the intermediate layer 10b is preferably 30% to 70%, more preferably 40% to 70%, and even more preferably 50% to 70%. If the volume ratio of the diamond particles 10d in the intermediate layer 10b is less than 30%, the rigidity of the intermediate layer 10b cannot be secured. Further, when the volume ratio of the diamond particles 10d exceeds 70%, the amount of the base material 10e in the intermediate layer 10b decreases, so that the stress generated due to impact or the like cannot be sufficiently reduced. 10c may be broken.

  Although not shown in the figure, a part of the diamond particles 10d forms an interface between the intermediate layer 10b and the coating layer 10c and is in contact with the coating layer 10c. At this time, when the intermediate layer 10b is viewed from the outside in the radial direction of the shaft member 10 (the direction perpendicular to the interface between the intermediate layer 10c and the coating layer 10c), the area ratio occupied by the diamond particles 10d is 10% to 40%. %, More preferably 20% to 30%.

Further, in order to the rigidity of the intermediate layer 10b further improved, - the value _{D 1} of the (thickness of the intermediate layer 10b the average particle size of the diamond particles 10d), it is preferable that the 0Myuemu～30myuemu, and 0μm~15μm Is more preferable.

  The coating layer 10c is made of DLC, covers the intermediate layer 10b, and is a sliding surface 13 whose outer surface is in sliding contact with the bearing member 11. Note that the thickness of the coating layer 10c is preferably 3 μm to 30 μm, and more preferably 6 μm to 25 μm. If the thickness of the coating layer 10c is less than 3 μm, the coating layer 10c may be cracked even when the rigidity of the intermediate layer 10b is high. Further, when the thickness of the coating layer 10c exceeds 30 μm, the external force becomes larger than the adhesive strength between the intermediate layer 10b and the coating layer 10c due to the thickness, and the coating layer 10c may peel off. Yes.

Further, - the value _{D 2} of {(thickness of the intermediate layer 10b the average particle of the diamond particles 10d diameter) / thickness of the coating layer 10c} is preferably 1.5 to 8. If D ₂ is less than 1.5 are unable to fully absorb the impact by an external force, and also beyond the D ₂ is 8, can not be obtained any more effect. The value of D ₂ With 1.5-8 is considered possible to sufficiently absorb the impact by an external force.

  Thus, in the shaft member 10 according to the present embodiment, the sliding surface 13 is formed of DLC having good slidability, and the rigid intermediate layer 10b is provided between the base 10a and the coating layer 10c. . Accordingly, the stress load on the coating layer 10c can be reduced, and the load resistance of the coating layer 10c can be improved. Therefore, it can be said that the shaft member 10 is a shaft member excellent in slidability and load resistance.

<Method of forming intermediate layer and coating layer>
Next, a method for forming the intermediate layer 10b on the base 10a will be described.

  As a method for forming the intermediate layer 10b, for example, electrolytic plating can be used. When forming the intermediate layer 10b by electrolytic plating, first, diamond particles 10d are added to a plating solution to be used. Next, the shaft member 10 is immersed in a plating solution, and the surface of the base 10a is plated by applying a current. Thereby, the intermediate layer 10b in which the diamond particles 10d are dispersed in the base material 10e can be formed. The plating solution is selected according to the material of the base material 10e. For example, a nickel plating solution is used when a nickel alloy is used as the base material 10e, and a cobalt plating solution is used when a cobalt alloy is used as the base material 10e.

  Then, a coating layer 10c is formed on the surface of the intermediate layer 10b thus formed. As a method for forming the coating layer 10c made of DLC, a known DLC film forming method can be used, for example, physical vapor deposition (PVD) using sputtering, chemical vapor deposition using plasma, or the like. Phase vapor deposition (CVD; Chemical Vapor Deposition) or the like can be used.

[Embodiment 2]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as the members described in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

  FIG. 2 is a schematic cross-sectional view showing a cross section perpendicular to the axial direction of the shaft / bearing structure 1B according to the present embodiment. As shown in FIG. 2, the shaft member 10 included in the shaft / bearing structure 1B according to the present embodiment is a contact particle in which the diamond particles 10d of a part of the intermediate layer 10b are in contact with the coating layer 10c. . That is, the intermediate layer 10b of the shaft member 10 according to the first embodiment has the diamond particles 10d dispersed and held in the base material 10e, whereas the intermediate layer 10b of the shaft member 10 according to the present embodiment has Has a convex portion at the interface with the coating layer 10c, and the convex portion is formed of contact particles that are diamond particles that come into contact with the coating layer 10c.

  Here, diamond and DLC have similar compositions. Because of this, the diamond particles 10d and the coating layer 10c made of DLC are in contact with each other, so that the adhesive strength between the intermediate layer 10b and the coating layer 10c is improved, and at the interface between the intermediate layer 10b and the coating layer 10c. Is less likely to occur. Thereby, the shaft member 10 excellent in load resistance can be provided.

  In addition, as the method of forming the intermediate layer 10b, the same method as in the first embodiment described above can be used. That is, by appropriately setting the particle diameter of the diamond particles 10d to be added to the plating solution and the conditions for plating, the intermediate layer according to the present embodiment in which some diamond particles 10d protrude from the base material 10e. 10b can be formed.

  Then, a coating layer 10c made of DLC is formed on the outer surface of the intermediate layer 10b thus formed by using the same method as in Embodiment 1, and the diamond particles 10d are covered with the coating layer 10c made of DLC. The shaft member 10 included in the shaft / bearing structure 1B according to the present embodiment can be manufactured.

  FIG. 3 is a view showing a state in which the shaft / bearing structure 1B according to the present embodiment is used for a bearing or the like and the coating layer 10c of the shaft member 10 is worn, and a cross section perpendicular to the axial direction of the shaft / bearing structure 1B. FIG. As shown in FIG. 3, in the shaft member 10 provided in the shaft / bearing structure 1B according to the present embodiment, the diamond particles 10d of a part of the intermediate layer 10b come into contact with the coating layer 10c due to the wear of the coating layer 10c. In addition to this, it has an exposed portion 14 exposed from the coating layer 10c. The exposed portion 14 and the sliding surface 13 are located on the same circumference around the axis of the shaft / bearing structure 1B. The shaft member 10 may be processed so as to be in a state as shown in FIG. 3 before use, but it is not preferable in terms of material and processing cost.

[Embodiment 3]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as the members described in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

  FIG. 4A is a schematic cross-sectional view showing a cross section perpendicular to the axial direction of the shaft / bearing structure 1C according to the present embodiment. As shown in FIG. 4A, in the shaft member 10 provided in the shaft / bearing structure 1C according to the present embodiment, the interface 15 between the intermediate layer 10b and the coating layer 10c is centered on the shaft of the shaft / bearing structure 1C. Are located on the same circumference. The contact particles, which are the diamond particles 10d in contact with the coating layer 10c, have the contact surface with the coating layer 10c located in the interface 15.

  Thus, in the shaft member 10 provided in the shaft / bearing structure 1C according to the present embodiment, the diamond particles 10d of the intermediate layer 10b and the coating layer 10c are in contact with each other, similarly to the shaft member 10 according to the second embodiment. Thus, the intermediate layer 10b and the coating layer 10c are bonded with high strength. Further, the contact surface of the diamond particles (contact particles) 10d in contact with the coating layer 10c is located within the interface 15 between the intermediate layer 10b and the coating layer 10c.

  Accordingly, even if the coating layer 10c is worn or peeled off due to the sliding between the shaft member 10 and the bearing member 11 due to long-term use, the sliding surface of the shaft member 10 as the sliding surface with the bearing member 11 is provided. Even if the moving surface 13 reaches the intermediate layer 10b, the shaft member 10 and the bearing member 11 slide on the interface 15 provided on the same circumference around the axis of the shaft / bearing structure 1C. Therefore, even if the coating layer 10c is worn or peeled, the aggressiveness of the shaft member 10 on the bearing member 11 is low, and the life of the shaft / bearing structure 1C can be extended. At this time, the contact surface of the diamond particles 10d may slightly protrude from the interface 15, and even if the contact surface of the diamond particles 10d slightly protrudes from the interface 15, the same effect as described above can be obtained. Can be.

  As a method of forming the intermediate layer 10b, first, similarly to the shaft member 10 according to the second embodiment, the shaft member 10 is immersed in a plating solution to which diamond particles 10d are added, and plating is performed. In this way, an intermediate layer 10b in which some diamond particles 10d protrude from the base material 10e is formed. Next, by processing the diamond particles 10d projecting from the base material 10e, the interface 15 is made to be on the same circumference around the axis of the shaft / bearing structure 1C. As a method of processing the diamond particles 10d, any method may be used as long as it is a method of grinding a material having high hardness, and for example, a method of grinding with a grindstone such as diamond or silicon carbide, or a method of performing electrical discharge machining can be used.

  The coating layer 10c made of DLC is formed on the outer surface of the intermediate layer 10b thus formed by using the same method as in the first embodiment, so that the shaft provided in the shaft / bearing structure 1C according to the present embodiment is formed. The member 10 can be manufactured.

  FIG. 4B is a diagram showing another example of the shaft / bearing structure 1C according to the present embodiment, and is a schematic cross-sectional view showing a cross section perpendicular to the axial direction of the shaft / bearing structure 1C. As shown in FIG. 4 (b), the shaft member 10 provided in the shaft / bearing structure 1C may be processed so that the diamond particles 10d have a substantially spherical contact surface (interface 15) side. The substantially spherical top of the diamond particle 10d is located on the interface 15 on the same circumference around the axis of the shaft / bearing structure 1C. Note that a method similar to the above-described method for processing the diamond particles 10d can be used as a processing method for making the tops of the diamond particles 10d substantially spherical.

[Embodiment 4]
Another embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, members having the same functions as the members described in the above embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

  FIG. 5 is a schematic cross-sectional view showing a cross section parallel to the axial direction of the shaft / bearing structure 1E according to the present embodiment.

  As shown in FIG. 5, the bearing member 11 has ends 11a at both ends in the axial direction. That is, in the bearing member 11, the end 11a is formed at an end of a surface (opposing surface) that is opposed to the shaft member 10 and that is parallel to the axial direction. Here, considering the case where the shaft member 10 rotates about the shaft, the shaft member 10 slides with respect to the bearing member 11. At this time, the rotation axis of the shaft member 10 may be tilted (blurred) due to vibration or the like. Therefore, in the shaft member 10, the position corresponding to the end 11 a of the bearing member 11 is more worn than the other positions. In the bearing member 11 according to the present embodiment, the intermediate layer 10b at the position corresponding to the end 11a of the bearing member 11, that is, at the position indicated by the arrow in FIG. In the intermediate layer 10b at the position, the volume ratio of the diamond particles 10d is low. Specifically, the volume ratio of the diamond particles 10d of the intermediate layer 10b at the position corresponding to the end 11a of the bearing member 11 is preferably 30% to 70%, and more preferably 40% to 70%. preferable. The volume fraction of diamond particles in the intermediate layer 10b at other positions is preferably 0% to 20%.

  As described above, in the intermediate layer 10b, a large amount of diamond particles 10d are arranged at positions where abrasion is severe, and abrasion resistance is enhanced by increasing the volume ratio of the diamond particles 10d. In addition, at other positions where wear is not so severe, the volume ratio of the diamond particles 10d in the intermediate layer 10b is reduced, and the usage of the diamond particles 10d is suppressed. Thus, the shaft member 10 having excellent wear resistance can be provided at low cost.

  As a method for forming such an intermediate layer, a method in which plating is performed twice is considered. That is, the positions where the volume ratios of the diamond particles 10d are different are plated respectively. For example, the shaft member 10 is immersed in a plating solution to which a small amount of the diamond particles 10d is added, and plating is performed in a state where the position corresponding to the end 11a of the bearing member 11 is masked. Then, the shaft member 10 is masked at a position other than the position corresponding to the end 11a of the bearing member 11, and is immersed in a plating solution containing a large amount of the diamond particles 10d to perform plating. Thus, it is possible to manufacture the shaft member 10 in which the volume ratio of the diamond particles 10d at the position corresponding to the end 11a of the bearing member 11 is higher than the volume ratio of the diamond particles 10d at other positions.

  In the present embodiment, the volume ratio of the diamond particles 10d of the intermediate layer 10b at the position corresponding to the end 11a of the bearing member 11 is made higher than at other positions. The configuration may be such that the diamond particles 10d are arranged only at the positions corresponding to the end portions 11a, and the intermediate layer 10b containing no diamond particles 10d is formed at other positions. The intermediate layer 10b on which the diamond particles 10d are provided may be provided only at the position corresponding to the end 11a of the bearing member 11, and the intermediate layer 10b may not be formed at other positions. .

  FIG. 6 is a schematic cross-sectional view showing a cross section parallel to the axial direction of the shaft / bearing structure 1F according to the present embodiment.

  As shown in FIG. 6, the base 10a may have a configuration in which a recess 10f is provided at a position corresponding to the end 11a of the bearing member 11, and the intermediate layer 10b is formed only in the recess 10f. As shown in FIG. 6, by providing the intermediate layer 10b only in the concave portion 10f, the usage of the diamond particles 10d can be further reduced, and the unevenness of the outer peripheral surface of the shaft member 10 can be eliminated. -It is possible to extend the life of the bearing structure 1F.

  In the present embodiment, an example is shown in which the end 11a is formed perpendicular to the surface where the shaft member 10 and the bearing member 11 face each other, but the end 11a may have any angle. And may be a curved surface.

(Modification)
In the embodiment described above, the case where the intermediate layer 10b is formed by plating has been described. However, the intermediate layer 10b may be formed using Spark Plasma Sintering (SPS) (hereinafter, referred to as SPS). . Specifically, first, diamond particles 10d are placed on the base 10a, and a hard metal powder (for example, a cobalt alloy powder) serving as the base material 10e is placed thereon. Then, the hard metal powder is compacted by pressure molding using the SPS device, and the intermediate layer 10b is formed.

  Further, in the above-described embodiment, the example in which the bearing member 11 as the slidable member has a cylindrical shape has been described. However, the shape of the bearing member 11 is not limited to this. It may be a flat bearing member that slides on a flat surface.

  The present invention is not limited to the above embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

[Example 1]
An intermediate layer having a thickness of 70 μm was formed on a surface of a stainless steel substrate having a length of 12 mm, a width of 16.65 mm and a thickness of 6 mm using a nickel plating solution to which diamond particles having an average particle diameter of 40 μm were added. At this time, the volume ratio of the diamond particles in the intermediate layer was 70%. Then, a coating layer of DLC was formed on the intermediate layer with a thickness of 14 μm by using the PVD method to prepare a test piece.

Next, a ring made of silicon nitride having an outer diameter of 139 mm, an inner diameter of 105 mm, and a thickness of 6 mm was used as a mating material, and a pin-on-disk method was applied for one hour under the conditions of a surface thickness of 0.3 MPa and a rotation speed of 3 m / sec. The test was performed, and the amount of wear was measured from the weight change before and after the test. As a result, the wear amount of the test piece was 1.9 × 10 ⁻⁴ g.

[Example 2]
Specimens were prepared in the same manner as in Example 1 except that diamond particles having an average particle diameter of 45 μm were used, the thickness of the intermediate layer was 75 μm, and the thickness of the coating layer was 20 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 67%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 2.4 × 10 ⁻⁴ g.

[Example 3]
Test pieces were prepared in the same manner as in Example 1, except that diamond particles having an average particle diameter of 100 μm were used, the thickness of the intermediate layer was 110 μm, and the thickness of the coating layer was 8 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 33%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the wear amount of the test piece was 4.5 × 10 ⁻⁴ g.

[Example 4]
Test pieces were prepared in the same manner as in Example 1, except that diamond particles having an average particle diameter of 30 μm were used, the thickness of the intermediate layer was 55 μm, and the thickness of the coating layer was 6 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 58%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 2.0 × 10 ⁻⁴ g.

[Example 5]
A test piece was prepared in the same manner as in Example 1 except that the diamond particles having an average particle diameter of 55 μm were used, the thickness of the intermediate layer was set to 70 μm, and the thickness of the coating layer was set to 10 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 55%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the wear amount of the test piece was 1.9 × 10 ⁻⁴ g.

[Example 6]
Test pieces were prepared in the same manner as in Example 1 except that the diamond particles having an average particle diameter of 35 μm were used, the thickness of the intermediate layer was set to 50 μm, and the thickness of the coating layer was set to 10 μm. At this time, the volume ratio of diamond particles in the intermediate layer was 53%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 3.2 × 10 ⁻⁴ g.

[Example 7]
Test pieces were prepared in the same manner as in Example 1, except that diamond particles having an average particle diameter of 40 μm were used, the thickness of the intermediate layer was set to 45 μm, and the thickness of the coating layer was set to 15 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 35%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the wear amount of the test piece was 4.5 × 10 ⁻⁴ g.

Example 8
Test pieces were prepared in the same manner as in Example 1, except that the diamond particles having an average particle diameter of 20 μm were used, the thickness of the intermediate layer was 30 μm, and the thickness of the coating layer was 15 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 33%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 8.8 × 10 ⁻⁴ g.

[Example 9]
Same as Example 1 except that a cobalt plating solution was used as a plating solution, diamond particles having an average particle diameter of 50 μm were used, the thickness of the intermediate layer was 75 μm, and the thickness of the coating layer was 1 μm. A test piece was prepared by the method described above. At this time, the volume ratio of the diamond particles in the intermediate layer was 45%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 4.3 × 10 ⁻⁴ g.

[Example 10]
Specimens were prepared in the same manner as in Example 1 except that diamond particles having an average particle diameter of 25 μm were used, the thickness of the intermediate layer was 60 μm, and the thickness of the coating layer was 3 μm. At this time, the volume ratio of diamond particles in the intermediate layer was 41%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the wear amount of the test piece was 4.2 × 10 ⁻⁴ g.

[Example 11]
Same as Example 1 except that a cobalt plating solution was used as a plating solution, a diamond particle having an average particle diameter of 35 μm was used, the thickness of the intermediate layer was 40 μm, and the thickness of the coating layer was 28 μm. A test piece was prepared by the method described above. At this time, the volume ratio of the diamond particles in the intermediate layer was 31%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the amount of wear of the test piece was 5.2 × 10 ⁻⁴ g.

[Example 12]
Test pieces were prepared in the same manner as in Example 1 except that the diamond particles having an average particle diameter of 15 μm were used, the thickness of the intermediate layer was 50 μm, and the thickness of the coating layer was 35 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 19%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 3.5 × 10 ⁻³ g.

[Example 13]
Test pieces were prepared in the same manner as in Example 1, except that diamond particles having an average particle diameter of 100 μm were used, the thickness of the intermediate layer was 90 μm, and the thickness of the coating layer was 23 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 23%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 3.2 × 10 ⁻³ g.

[Example 14]
Test pieces were prepared in the same manner as in Example 1, except that diamond particles having an average particle diameter of 30 μm were used, the thickness of the intermediate layer was 70 μm, and the thickness of the coating layer was 4 μm. At this time, the volume ratio of the diamond particles in the intermediate layer was 75%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 3.9 × 10 ⁻³ g.

[Comparative Example 1]
In place of the diamond particles, silicon carbide particles having an average particle diameter of 50 μm were used, the thickness of the intermediate layer was set to 135 μm, and the thickness of the coating layer was set to 10 μm. Produced. At this time, the volume ratio of silicon carbide particles in the intermediate layer was 20%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 4.2 × 10 ⁻³ g.

[Comparative Example 2]
A test piece was prepared in the same manner as in Example 1, except that the intermediate layer was formed with a thickness of 3 μm without adding diamond particles to the plating solution, and the thickness of the coating layer was changed to 2 μm. Then, a friction test was performed under the same conditions as in Example 1. As a result, the abrasion loss of the test piece was 7.9 × 10 ⁻³ g.

[Comparative Example 3]
Instead of diamond particles, silicon nitride particles having an average particle diameter of 65 μm were used, the thickness of the intermediate layer was set to 70 μm, and the thickness of the coating layer was set to 23 μm. Produced. At this time, the volume ratio of the silicon nitride particles in the intermediate layer was 28%. Then, a friction test was performed under the same conditions as in Example 1. As a result, the wear amount of the test piece was 3.7 × 10 ⁻³ g.

  Table 1 is a table showing various conditions and test results of test pieces prepared in Examples 1 to 14 and Comparative Examples 1 to 3 and subjected to a friction test.

  As shown in Table 1, Comparative Examples 1 to 3 in which the intermediate layer did not contain diamond particles had a greater wear amount than Examples 1 to 13 in which the intermediate layer contained diamond particles, and peeling of the coating layer was less. Was seen.

  In Examples 1 to 14 in which the thickness of the intermediate layer was 30 µm to 120 µm, it was confirmed that a bearing member having a small amount of abrasion and excellent in slidability and abrasion resistance was obtained.

  Further, in Examples 1, 2, 4 to 6, 9, 10, and 14 in which the film thickness of the intermediate layer is 50 μm to 100 μm, the bearings having even smaller wear amount of the test pieces and more excellent wear resistance. It was confirmed that a member was obtained.

  In Examples 1 to 11 in which the volume ratio of diamond particles in the intermediate layer is 30% to 70%, Example 12 in which the volume ratio of diamond particles is 19%, and in Example 12 in which the volume ratio of diamond particles is 23%, It was confirmed that the amount of wear of the test piece was smaller than that of Example 13, and a bearing member having excellent wear resistance was obtained.

  Further, in Examples 1, 2, 4 to 6, 9, and 10 in which the volume ratio of diamond particles in the intermediate layer is 40% to 70%, Example 3 in which the volume ratio of diamond particles is 30% or more and less than 40%. , 7, 8 and 11, it was confirmed that the amount of wear of the test piece was small and a bearing member excellent in wear resistance was obtained.

  In Examples 1, 2, 4 to 6 in which the volume ratio of diamond particles in the intermediate layer is 50% to 70%, the test was performed in comparison with Examples 9 and 10 in which the volume ratio of diamond particles was less than 50%. It was confirmed that a small wear amount of the piece was obtained, and a bearing member having excellent wear resistance was obtained.

  Further, it was confirmed that the thickness of the coating layer was preferably 3 μm to 30 μm, more preferably 6 μm to 25 μm.

[Example 15]
Next, a shaft / bearing model was prepared, and a friction test was performed. A bearing having an inner diameter of 85.5 mm, an outer diameter of 103 mm, and a length of 60 mm was used as a bearing, and a bearing member made of silicon nitride having a length of 30 mm was used for a sliding portion with the shaft member.

  The base material of the shaft member was made of SUS and had an outer diameter of 85 mm, an inner diameter of 72 mm, and a length of 100 mm. Then, an intermediate layer having a thickness of 50 μm was formed at positions corresponding to the ends provided at both ends in the axial direction of the bearing member using a nickel plating solution to which diamond particles having an average particle diameter of 20 μm were added. An intermediate layer having a thickness of 50 μm was formed at a position other than the position corresponding to the end using a nickel plating solution to which diamond particles having an average particle diameter of 20 μm were added. At this time, the volume ratio of diamond particles in the intermediate layer at the position corresponding to the end was 42%, and the volume ratio of diamond particles in the intermediate layer at other positions was 20%.

  Next, a coating layer made of DLC was formed in a thickness of 25 μm on the outer surface of the intermediate layer in the same manner as in Example 1 to produce a shaft member.

  These were combined, and a sliding test was performed for 1 hour in a state where the rotational speed was 6 m / sec and the unbalance amount G was 0 or less, and the surface of the coating layer after the test was observed.

[Example 16]
The intermediate layer is formed at a position corresponding to the end with a thickness of 55 μm using a nickel plating solution to which diamond particles having an average particle diameter of 30 μm are added, and at other positions, a diamond having an average particle diameter of 30 μm is formed. A shaft member was produced in the same manner as in Example 14, except that the intermediate layer was formed with a thickness of 55 μm using a nickel plating solution to which particles were added, and the thickness of the coating layer was changed to 6 μm. . At this time, the volume ratio of diamond particles in the intermediate layer at the position corresponding to the end was 58%, and the volume ratio of diamond particles in the intermediate layer at other positions was 5%.

  Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

[Example 17]
At a position corresponding to the end portion, an intermediate layer having a thickness of 80 μm was formed using a nickel plating solution to which diamond particles having an average particle diameter of 50 μm were added, and diamond particles were added at other positions. A shaft member was manufactured in the same manner as in Example 15 except that the intermediate layer was formed with a thickness of 80 μm using a nickel plating solution that was not used, and the thickness of the coating layer was changed to 22 μm. At this time, the volume ratio of the diamond particles in the intermediate layer at the position corresponding to the end was 67%, and the volume ratio of the diamond particles in the intermediate layer at other positions was 0% because the diamond particles were not included. Was.

  Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

[Example 18]
At a position corresponding to the end portion, an intermediate layer having a thickness of 120 μm is formed using a nickel plating solution to which diamond particles having an average particle size of 100 μm are added, and at other positions, a diamond having an average particle size of 80 μm is formed. A shaft member was produced in the same manner as in Example 15, except that an intermediate layer was formed with a thickness of 120 μm using a nickel plating solution to which particles were added, and the thickness of the coating layer was changed to 8 μm. . At this time, the volume ratio of diamond particles in the intermediate layer at the position corresponding to the end was 64%, and the volume ratio of diamond particles in the intermediate layer at other positions was 10%.

  Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

[Example 19]
At a position corresponding to the end portion, an intermediate layer having a thickness of 70 μm was formed using a nickel plating solution containing diamond particles having an average particle diameter of 30 μm, and diamond particles were added at other positions. A shaft member was manufactured in the same manner as in Example 15 except that the intermediate layer was formed with a thickness of 70 μm using a nickel plating solution that was not used, and the thickness of the coating layer was changed to 4 μm. At this time, the volume ratio of the diamond particles in the intermediate layer at the position corresponding to the end is 75%, and the volume ratio of the diamond particles in the intermediate layer at other positions is 0% since the diamond particles are not included. Was.

  Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

[Comparative Example 4]
No intermediate layer was formed at the position corresponding to the end, and a 90 μm-thick intermediate layer was formed at other positions using nickel plating to which diamond particles were not added, and the thickness of the coating layer was 14 μm. A shaft member was produced in the same manner as in Example 15 except for the above. Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

[Comparative Example 5]
A shaft member was produced in the same manner as in Comparative Example 4, except that the intermediate layer was not provided at the position corresponding to the end portion or at any other position, and the film thickness of the coating layer was 10 μm. Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

[Comparative Example 6]
A shaft member was produced in the same manner as in Comparative Example 5, except that the thickness of the coating layer was changed to 5 μm. Then, a test was performed under the same conditions as in Example 15, and the surface of the coating layer after the test was observed.

  Table 2 is a table showing various conditions and test results of shaft members produced in Examples 15 to 19 and Comparative Examples 4 to 6 and subjected to a sliding test.

  In Table 2, a circle (○) indicates that the abrasion of the coating layer after the test was not affected, and a triangle (△) indicates that slight peeling was observed in the coating layer. , Crosses (x) indicate that the coating layer was peeled off.

  As shown in Table 2, it was confirmed that Examples 15 to 18 in which diamond particles were arranged at least at positions corresponding to the ends of the bearing member had excellent wear resistance. Also, by comparing Comparative Example 4 in which an intermediate layer containing no diamond particles was provided at a position other than the position corresponding to the end of the bearing member with Comparative Examples 5 and 6 in which no intermediate layer was provided, It was confirmed that it is better to provide the intermediate layer at a position other than the position corresponding to the end portion even if no diamond particles are contained.

  In Example 19 in which the volume ratio of the diamond particles in the intermediate layer at the position corresponding to the end of the bearing member was 75%, the abrasion of the coating layer after the test was not affected. When observed, small cracks were observed. This is considered to be because the amount of the base material in the intermediate layer at the position corresponding to the end of the bearing member was small, and the coating layer was broken by an impact due to contact of the end of the bearing member and the like. It was confirmed that the volume ratio of the particles was preferably 70% or less.

  INDUSTRIAL APPLICATION This invention can be utilized for the sliding member used for a pump etc., for example.

1A, 1B, 1C, 1E, 1F Shaft / bearing structure 10 Shaft member 10a Base material 10b Intermediate layer 10c Coating layer 10d Diamond particles 10e Base material 11 Bearing member 11a End 15 Interface

Claims (9)

A sliding member that is used in a shaft / bearing structure having a shaft and a bearing, and slides relatively to a sliding member,
A substrate;
A coating layer containing diamond-like carbon, which is in sliding contact with the sliding member,
An intermediate layer that is provided between the base and the coating layer and includes diamond particles and a base material,
The film thickness of the intermediate layer, Ri 30μm~120μm der,
The average diameter of the diamond particles is 20 μm to 120 μm .   The sliding member according to claim 1, wherein a part of the diamond particles is a contact particle in contact with the coating layer. The intermediate layer has a convex portion at an interface between the intermediate layer and the coating layer,
The sliding member according to claim 2, wherein the protrusion is formed of the contact particles. The interface between the intermediate layer and the coating layer is located on the same circumference around the axis of the shaft / bearing structure,
The sliding member according to claim 2, wherein the contact particles are in contact with the coating layer at the interface.   The sliding member according to any one of claims 1 to 4, wherein the volume ratio of the diamond particles in the intermediate layer is 30% to 70%.   The sliding member according to any one of claims 1 to 5, wherein the base material is a nickel alloy, a cobalt alloy, a copper alloy, or an iron alloy.   The intermediate layer is provided at least at a position corresponding to an end of a surface of the slidable member facing the sliding member parallel to an axial direction of the shaft / bearing structure. Item 7. The sliding member according to any one of Items 1 to 6.   The volume ratio of the diamond particles in the intermediate layer at the position corresponding to the end of the surface of the sliding member facing the sliding member parallel to the axial direction of the shaft / bearing structure is the other position. The sliding member according to any one of claims 1 to 6, wherein the volume ratio is higher than the volume ratio in (1).   A pump using the sliding member according to claim 1.

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