JP7023106B2 - Sliding member - Google Patents

Description

The present invention relates to a sliding member and its use, particularly a sliding member that can be suitably used for a pump.

As a kind of drainage pump, a preceding standby operation pump is known. The preceding standby operation pump can operate at full speed in an anhydrous state in advance (preceding standby operation) and drain water in a mixed state of air and water in order to cope with a sudden increase in water volume such as guerrilla rainstorm. It has become. For example, Patent Document 1 discloses a sliding member applicable to such a preceding standby operation pump.

The sliding member described in Patent Document 1 is a sliding member that slides relatively with respect to the sliding member, and is scattered and fixed to the sliding member base and the surface of the sliding member base. In addition, it is provided with sliding contact particles that are in sliding contact with the sliding member, and the sliding contact particles are configured to protrude from the surface of the sliding member base.

Japanese Unexamined Patent Publication No. 2016-21727 (published on December 15, 2016)

A sliding member is provided on the shaft portion constituting the pump or the like, and it has been an issue to provide a sliding member having good slidability. In order to solve this problem, the sliding member described in Patent Document 1 has been developed. The sliding member described in Patent Document 1 has been useful in solving the above-mentioned problems.

By the way, in the sliding member described in Patent Document 1, sliding contact particles having an average particle diameter of 10 to 500 μm are fixed to the outer periphery of a sleeve (sliding member base) as sliding contact particles, and the surface of the sliding contact particles is ground. By doing so, it was produced. In sliding between the sliding member and the sliding member, a group of sliding contact particles having a processed sliding contact surface (particle sliding contact surface) slides so as to be in contact with the sliding member. Here, consider a case where the sum of the areas of the particle sliding contact surfaces per unit surface area of the sleeve greatly deviates from the average value of the sum of the areas of the particle sliding contact surfaces per at least two or more unit surface areas of the sleeve. In this case, where the sum of the areas of the particle sliding contact surfaces per unit surface area of the sleeve is smaller than the above average value, the particle sliding contact surfaces receive a large pressure, and the sliding is accompanied by a high surface pressure. As a result, the sliding member (sliding contact particles) is likely to be unevenly worn, and the aggression to the sliding member, which is the mating material for sliding, is increased, so that the sliding member may be worn more. be. Here, the cause of the change in the sum of the areas of the particle sliding contact surfaces of the sliding contact particles is the dimensional accuracy (cylindricity, coaxiality, outside) of the base material (sliding member base) on which the sliding contact particles are applied (fixed). Diameter size) and the like.

Uneven wear of the sliding member may cause deterioration of the sliding member and the device including the sliding member, and may hinder the long-term use of the device. From the viewpoint of suppressing uneven wear of the sliding member, there was room for improvement in the sliding member described in Patent Document 1, and therefore, development of a new sliding member capable of suppressing uneven wear of the sliding member. Was desired.

The present invention has been made from such a viewpoint, and an object of the present invention is to provide a sliding member having excellent slidability.

As a result of diligent studies to achieve the above object, the inventor of the present application has determined the slidability by keeping the sum of the areas of the particle sliding contact surfaces per unit surface area of the sliding member base within a predetermined range. We have found that it can be improved and have completed the present invention. That is, the invention of the present application includes the following inventions.

[1] A sliding member that slides relatively with respect to the sliding member, and includes a sliding member base and sliding contact particles scattered and fixed on the surface of the sliding member base. The sliding contact particles have a particle sliding contact surface that protrudes from the surface of the sliding member base and is in sliding contact with the sliding member, and is described above per unit surface area of the sliding member base. The sum of the areas of the particle sliding contact surfaces is 75% to 125% when the average value of the sum of the areas of the particle sliding contact surfaces per at least two or more unit surface areas of the sliding member base is 100%. A sliding member, characterized in that it is within the range.

[2] The surface density according to [1], which is the ratio of the area occupied by the sliding contact particles when viewed from the vertical direction of the surface of the sliding member base. Sliding member.

[3] The sliding member according to [1] or [2], wherein the average particle size of the sliding contact particles is 10 to 250 μm.

[4] Any one of [1] to [3], wherein the average height from the surface of the sliding member base to the particle sliding contact surface of the sliding contact particles is 0.8 μm or more. The sliding member described in 1.

[5] The sliding contact particles include diamond particles, diamond-like carbon particles, cubic boron nitride, glassy carbon particles, alumina particles, boron carbide particles, silicon carbide particles, tungsten carbide particles, silicon nitride particles, and molybdenum carbide particles. The sliding member according to any one of [1] to [4], which comprises at least one of them.

[6] Used in a shaft / bearing structure having a shaft and a bearing, the particle sliding contact surface is characterized to be on the same circumference centered on the shaft of the shaft / bearing structure [1] to [ 5] The sliding member according to any one of.

[7] The sliding member according to any one of [1] to [6], wherein the sliding contact particles are at least partially covered with a coating film.

According to one aspect of the present invention, it is possible to provide a sliding member having excellent slidability.

FIG. 5 is a schematic cross-sectional view showing a cross section perpendicular to the axial direction of a shaft / bearing structure including a sliding member and a sliding member according to an embodiment of the present invention. It is a top view which shows the structure seen from the outer surface side of the sliding member which concerns on one Embodiment of this invention. It is sectional drawing which shows the state which the sliding contact particle of the sliding member which concerns on one Embodiment of this invention is electrodeposited on the sliding member base. It is a graph which shows the relationship between a surface pressure and a wear amount in a reciprocating sliding test.

An embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications can be made within the scope of the claims. The present invention also includes embodiments and examples obtained by appropriately combining the technical means disclosed in different embodiments and examples within the technical scope of the present invention. In addition, all the academic documents and patent documents described in the present specification are incorporated as references in the present specification. Further, unless otherwise specified in the present specification, "A to B" representing a numerical range is intended to be "A or more (including A and larger than A) and B or less (including B and smaller than B)".

In the following description of the present specification, X according to an embodiment of the present invention, or X according to an aspect of the present invention (X is an arbitrary proper noun, for example, a sliding member, a sliding contact particle, a particle sliding contact surface, etc. Etc.) may be simply referred to as "book X".

[1. Sliding member]
The sliding member according to one aspect of the present invention is a sliding member that slides relatively with respect to the sliding member, and is scattered and fixed to the surface of the sliding member base and the sliding member base. The sliding contact particles are provided with the sliding contact particles, and the sliding contact particles protrude from the surface of the sliding member base and have a particle sliding contact surface that is in sliding contact with the sliding member. The sum of the areas of the particle sliding contact surfaces per unit surface area of the moving member base is 100%, which is the average value of the sum of the areas of the particle sliding contact surfaces per at least two or more unit surface areas of the sliding member base. When it is, it is characterized in that it is in the range of 75% to 125%.

In the present specification, "the sum of the areas of the particle sliding contact surfaces per unit surface area of the sliding member base" is also referred to as "the sum of the areas of the particle sliding contact surfaces". Further, in the present specification, "the average value of the sum of the areas of the particle sliding contact surfaces per at least two or more unit surface areas of the sliding member base" is referred to as "the average value of the sum of the areas" or simply "the average value". Also called "value".

According to the above configuration, the sliding member has sliding contact particles protruding from the surface of the sliding member base. As a result, the sliding member is in sliding contact with the particle sliding contact surface of the sliding contact particles, and is not in sliding contact with the surface of the sliding member base. As a result, the sliding member has a low coefficient of friction, suppresses the generation of heat due to friction, and becomes a member with excellent durability.

Further, according to the above configuration, in the sliding member, since the sliding contact particles are scattered on the outer surface of the sliding member base, there is a region (interparticle region) in which the sliding contact particles do not exist between the sliding contact particles. It is formed. Therefore, when the sliding member base portion thermally expands due to an increase in temperature, the sliding contact particles fixed on the outer surface of the sliding member base portion can move in association with the thermal expansion. In other words, the sliding contact particles move with the thermal expansion of the sliding member base. Therefore, it is not necessary to match the coefficient of thermal expansion between the sliding member base and the sliding contact particles, and the material selectivity of the sliding member base is wide.

Further, the slurry liquid described later invades the interparticle region, so that the chance of the slurry liquid coming into contact with the sliding member can be reduced. Therefore, it can be expected that the wear of the sliding member is suppressed. The interparticle region plays an important role in preventing damage to the sliding member base and the sliding member due to the solid substance by holding the solid substance (also referred to as slurry particle) in the slurry liquid. Fulfill.

Further, according to the above configuration, the sum of the areas of the particle sliding contact surfaces is in the range of 75% to 125% when the average value of the sum of the areas is 100%. This makes it possible for the sliding member to include sliding contact particles in which the sum of the areas of the particle sliding contact surfaces and the protruding height of the sliding contact particles are aligned in a predetermined range. Therefore, when the sliding member is in sliding contact with the sliding member, the surface pressure on both of the sliding members is within a predetermined range. As a result, uneven wear of the sliding contact particles when the sliding member and the sliding member are in sliding contact can be suppressed, and wear of the sliding member can be suppressed. Further, when the wear of the sliding member is significant, the sliding member becomes uneven wear, but with the above configuration, the uneven wear can also be suppressed.

Further, according to the above configuration, the sliding contact particles sufficiently secure both "a protruding portion (protruding height) from the surface of the sliding member base" and "a fixing portion to the sliding member base". Can be done. According to the above configuration, it is possible to keep the protruding height of the sliding contact particles within a certain range.

<Structure of sliding member>
The sliding member according to one aspect of the present invention will be described below with reference to FIGS. 1 to 4. In the following embodiment, a shaft member having a shaft / bearing structure in a rotary mechanism used for a pump for discharging water (also referred to as a slurry liquid) containing earth and sand (slurry particles) as a sliding member will be described. .. However, the present sliding member is not limited to the above-mentioned shaft member as long as it is a member that slides relative to the sliding member. For example, it can be applied to a bearing member in a shaft / bearing structure that slides relatively with respect to the shaft member.

FIG. 1 is a schematic cross-sectional view showing a cross section of a shaft / bearing structure 1A including a sliding member according to one aspect of the present invention, which is perpendicular to the axial direction.

As shown in FIG. 1, the shaft / bearing structure 1A includes a shaft member 10 as a sliding member and a bearing member 11 as a sliding member. The shaft member 10 is a cylindrical shaft sleeve. The shaft member 10 is not limited to the shaft sleeve, but may be a shaft.

As shown in FIG. 1, the shaft member 10 includes at least a substrate 10a as a base of a sliding member and sliding contact particles 10b scattered and fixed on the outer surface of the substrate 10a. The substrate 10a has a cylindrical shape. Further, since the sliding contact particles 10b are scattered on the outer surface of the substrate 10a, a region (hereinafter, interparticle region) 12 in which the sliding contact particles 10b do not exist is formed between the sliding contact particles 10b. In addition, in FIG. 1, only a part of the sliding contact particles 10b scattered on the entire outer surface of the substrate 10a is shown.

The shaft member 10 may include a fixing member (not shown in FIG. 1) for fixing the sliding contact particles 10b on the outer surface of the substrate 10a. That is, the base portion of the shaft member 10 (that is, the base portion of the sliding member) may be composed of only the substrate 10a, or may be composed of the substrate 10a and the fixing member. When the base of the shaft member 10 is composed of only the base 10a, the surface of the base of the shaft member 10 is the outer surface of the base 10a. When the base of the shaft member 10 is composed of the substrate 10a and the fixing member, the surface of the base of the shaft member 10 is the outer surface of the fixing member.

Examples of the fixing member include a metal film such as a nickel phosphorus film used for fixing the sliding contact particles 10b by electrodeposition, a brazing material used for fixing the sliding contact particles 10b by brazing, and the like.

Further, the shaft member 10 may include particles having the same material as the sliding contact particles 10b and having a smaller particle diameter than the sliding contact particles 10b in the interparticle region 12. The particles are, for example, particles that are inevitably provided due to the particle size distribution of the powder that is the raw material of the sliding contact particles 10b when the shaft member 10 is manufactured.

The substrate 10a is made of a generally used material, and is made of, for example, a Co-based or Ni-based hard alloy. The hardness of the substrate 10a is preferably Hv 600 kg / mm ² or more, and more preferably Hv 800 kg / mm ² or more. Since the hardness of the silica sand, which is the main component of the solid substance contained in the slurry liquid, is about Hv 1000 kg / mm ² , the hardness of the substrate 10a is brought close to the hardness of the silica sand (Hv 1000 kg / mm ² ) to bring the solid substance to the hardness. Damage to the substrate 10a due to the above can be reduced or suppressed. Further, the surface roughness Ra of the substrate 10a is preferably 1.0 μm or less.

On the other hand, when the sliding contact particles 10b are fixed to the substrate 10a by the fixing member, the fixing member coats the substrate 10a, so that the substrate 10a has a hardness of less than Hv 600 kg / mm ² (for example, SUS304 or the like). (Stainless steel) can also be preferably used.

The sliding contact particles 10b have a particle sliding contact surface 13 that protrudes from the surface of the substrate 10a and is in sliding contact with the bearing member 11. The sliding contact particles 10b support the bearing member 11 by being loaded by sliding contact with the bearing member 11 via the particle sliding contact surface 13. Since the shaft / bearing structure 1A including the sliding member (shaft member) 10 according to one aspect of the present invention is used for the preceding standby operation pump that also discharges the slurry liquid, the hardness of the sliding contact particles 10b is determined. It is preferable that the hardness is equal to or higher than that of silica sand.

In the sliding member (shaft member) 10 according to one aspect of the present invention, the sliding contact particles 10b are diamond particles, diamond-like carbon particles (Diamond-like Carbon particles (hereinafter referred to as DLC particles)), cubic boron nitride, and the like. It may be configured to contain at least one of glassy carbon particles, alumina particles, boron carbide particles, silicon carbide particles, tungsten carbide particles, silicon nitride particles and molybdenum carbide particles.

According to the above configuration, since the friction coefficient of each of the particles is low, the sliding member containing at least one of the particles as a sliding contact particle is a lubricant such as water between the sliding member and the sliding member. It can slide smoothly even under non-lubricated conditions where there is no particle. Further, the low coefficient of friction suppresses the generation of heat due to friction and improves the durability of the material.

Here, the diamond particles include single crystal particles of diamond and particles obtained by crushing a diamond sintered body. Further, the DLC particles include particles obtained by granulating DLC powder using a binder and particles obtained by crushing a sintered body of DLC powder.

The sliding contact particles 10b are scattered on the outer surface of the substrate 10a with a thickness of one particle. That is, another sliding contact particle 10b is rarely fixed on the particles of the sliding contact particle 10b fixed on the substrate 10a. There may be locations on the outer surface of the substrate 10a where two or more different sliding contact particles 10b are adjacent to each other. However, the adjacent different sliding contact particles 10b are not joined.

FIG. 2 is a top view showing a configuration of the shaft member 10 included in the shaft / bearing structure 1A as viewed from the outer surface side. As shown in FIG. 2, the sliding contact particles 10b have a particle sliding contact surface 13, and an interparticle region 12 is formed between the sliding contact particles 10b.

The sum of the areas of the particle sliding contact surfaces 13 per unit surface area of the substrate 10a is 75 when the average value of the sum of the areas of the particle sliding contact surfaces 13 per at least two or more unit surface areas of the substrate 10a is 100%. It is in the range of% to 125%. Here, the unit surface area preferably includes at least two or more particle sliding contact surfaces 13. As will be described later, the sum of the areas of the particle sliding contact surfaces 13 can be measured based on a micrograph obtained by observing the unit surface of the substrate 10a with a laser microscope.

The unit surface of the substrate 10a selected when obtaining the average value of the sum of the areas of the particle sliding contact surfaces 13 per the unit surface area of the substrate 10a is at least 2 or more, preferably 10 or more, preferably 20 or more. Is more preferable, 40 or more is further preferable, and 80 or more is particularly preferable. Further, it is preferable that the unit surface of the substrate 10a selected when obtaining the average value of the sum of the areas of the particle sliding contact surfaces 13 is randomly selected and evenly selected from the entire substrate 10a. The size of the unit surface is not particularly limited, and is appropriately set depending on the size of the substrate 10a and the like.

For example, when the substrate 10a is a shaft sleeve having a diameter of 85 mm × 100 mm L, the unit surface of the substrate 10a selected when obtaining the average value of the sum of the areas of the particle sliding contact surfaces 13 is 10 points from the circumferential direction. In addition, 8 locations from the axial direction, a total of 80 locations (10 × 8) can be selected. Further, at this time, the unit surface of the substrate 10a may have a size of 1 mm × 1 mm.

The particle sliding contact surface 13 of the sliding contact particles 10b is formed by processing the tip of the sliding contact particles 10b (in other words, the end portion on the bearing member 11 side) by a method described later. Therefore, the fact that the sum of the areas of the particle sliding contact surfaces 13 per unit surface area of the substrate 10a is larger than the average value means that the degree of processing (for example, grinding) of the sliding contact particles 10b is large on the unit surface. Means. On the other hand, the fact that the sum of the areas of the particle sliding contact surfaces 13 per unit surface area of the substrate 10a is smaller than the average means that the degree of processing of the sliding contact particles 10b is small on the unit surface.

The degree of processing of the sliding contact particles 10b and the protrusion height of the sliding contact particles 10b from the surface of the substrate 10a are correlated, and the more the tip of the sliding contact particles 10b is scraped by the processing, the smaller the protrusion height becomes.

The area of the particle sliding contact surface 13 correlates with the surface pressure on both the sliding contact particles 10b (particle sliding contact surface 13) and the bearing member 11 when the shaft member 10 and the bearing member 11 slide. The smaller the area of the particle sliding contact surface 13, the larger the surface pressure. The increase in the surface pressure may cause uneven wear of the sliding contact particles 10b and / or may cause wear of the bearing member 11.

In the sliding member (shaft member) 10 according to one aspect of the present invention, the sum of the areas of the particle sliding contact surfaces 13 is 75% or more when the average value of the sum of the areas is 100%. Therefore, since the sum of the areas of the particle sliding contact surfaces 13 is not too small, uneven wear of the sliding contact particles 10b and / or wear of the bearing member 11 when the shaft member 10 and the bearing member 11 slide is suppressed. Can be done. In the present specification, in Examples described later, it is demonstrated that an increase in surface pressure causes an increase in the amount of wear in the sliding member.

In the sliding member (shaft member) 10 according to one aspect of the present invention, the sum of the areas of the particle sliding contact surfaces 13 is 125% or less when the average value of the sum of the areas is 100%. That is, since the degree of processing of the sliding contact particles 10b is within a certain range and is not too large, it is possible to secure a protrusion height of a certain level or more for the protrusion of the sliding contact particles 10b. This makes it possible to prevent sliding contact between the bearing member 11 and the base portion of the shaft member 10. Therefore, with the sliding member (shaft member) 10 according to one aspect of the present invention, the coefficient of friction at the sliding contact between the bearing member 11 and the shaft member 10 can be reduced. Further, since the protrusion height of a certain level or more can be secured, there is an advantage that the wear of the base portion of the shaft member 10 due to the solid material in the slurry can be sufficiently suppressed.

The sliding member (shaft member) 10 according to one aspect of the present invention may have a configuration in which the average particle diameter of the sliding contact particles 10b is 10 to 250 μm. According to the above configuration, since the average particle diameter of the sliding contact particles 10b is 10 μm or more, it is possible to secure a fixed portion of the sliding contact particles 10b, thereby improving the peeling resistance of the sliding contact particles 10b. The fixed portion of the sliding contact particles 10b is a portion of the sliding contact particles 10b that is embedded in the substrate 10a or the substrate 10a and the fixing member. In other words, the fixed portion of the sliding contact particles 10b is a portion of the sliding contact particles 10b that is not a portion (also referred to as a protruding portion) protruding from the surface of the shaft member 10. The peeling resistance of the sliding contact particles 10b is intended to be difficult for the sliding contact particles 10b to be peeled off (dropped off) from the substrate 10a. Therefore, the high peel resistance is intended that the sliding contact particles 10b are difficult to peel from the substrate 10a.

Further, according to the above configuration, since the average particle diameter of the sliding contact particles 10b is 250 μm or less, (1) the amount of expensive sliding contact particles 10b used can be suppressed, and (2) the sliding contact particles are hard particles. It is possible to reduce the difficulty of processing the contact particles 10b, and (3) it is embedded in the fixing portion (base 10a or the base 10a and the fixing member) of the sliding contact particles 10b at the time of processing the sliding contact particles 10b. The load on the part) can be reduced. The difficulty in processing the sliding contact particles 10b can be said to be the difficulty in forming the particle sliding contact surface 13.

In the present specification, the average particle size of the sliding contact particles 10b is a value measured by a laser diffraction type particle size distribution measuring device: Shimadzu Corporation, SALD-2100. As described above, in order for the sliding contact particles 10b to have the particle sliding contact surface 13, the tip of the sliding contact particles 10b (in other words, the end on the bearing member 11 side) is processed by the method described later. Needs to form the particle sliding contact surface 13. As used herein, the "average particle size of the sliding contact particles" means the average particle size of the sliding contact particles before the above processing.

Since the hardness of the solid substance contained in the slurry liquid is about Hv 1000 kg / mm ² , the faster the moving speed of the slurry liquid is, the more the solid substance comes into contact with the base portion (base 10a) of the shaft member 10. The force applied to the base is increased, and the base is easily worn.

On the other hand, in the sliding member (shaft member) 10 according to one aspect of the present invention, since the average particle diameter of the sliding contact particles 10b is 10 to 250 μm, the sliding member (shaft member) 10 penetrates between the shaft member 10 and the bearing member 11 and has particles. The slurry liquid moving in the inter-region 12 easily comes into contact with the sliding contact particles 10b. When the slurry liquid comes into contact with the sliding contact particles 10b, the moving speed of the slurry liquid decreases, so that the impact applied to the base portion (base 10a) of the shaft member 10 can be softened, and the wear of the base portion of the shaft member 10 is sufficiently suppressed. can do. As a result, a large fixing allowance for the sliding contact particles 10b (fixing portion of the sliding contact particles 10b) can be secured at the base of the shaft member 10, so that the sliding contact particles 10b can be stably fixed and used for a long period of time. be able to.

The average particle size of the sliding contact particles 10b is preferably 100 to 250 μm, more preferably 150 to 250 μm, and even more preferably 200 to 250 μm.

Here, particles (for example, hard particles) that are raw materials for the sliding contact particles 10b and become sliding contact particles 10b by processing are referred to as raw material particles. Regarding the raw material particles, the particle size of the plurality of raw material particles corresponding to 60% on a volume basis with respect to all the raw material particles is in the range of 75% to 125% when the average particle size of the raw material particles is 100%. Is preferable. With the above configuration, since the particle size of the raw material particles is small, it is possible to suppress an increase in the number of particles that do not become sliding contact particles 10b from the raw material particles. Further, with the above configuration, it is possible to suppress an increase in cost associated with the processing of the sliding contact particles 10b for forming the particle sliding contact surface 13. That is, there is an advantage that it is not necessary to perform unnecessary or extra processing on the sliding contact particles 10b for forming the particle sliding contact surface 13. The above-mentioned "particles that do not become sliding contact particles 10b" mean particles that cannot be in sliding contact with the sliding member (bearing) 11.

The sliding member (shaft member) 10 according to one aspect of the present invention has an average height (also referred to as a protruding height) of 0.8 μm from the surface of the substrate 10a to the particle sliding contact surface 13 of the sliding contact particles 10b. The above configuration may be used. According to the above configuration, in the shaft member 10, the sliding contact particles 10b protrude from the surface of the substrate 10a, the bearing member 11 slides into contact with the particle sliding contact surface 13 of the sliding contact particles 10b, and does not slide with the surface of the substrate 10a. The state can be maintained. Further, as described above, the portion of the sliding contact particles 10b protruding from the surface of the substrate 10a can reduce the moving speed of the slurry liquid. The protrusion height can be measured using a laser microscope.

The protruding height of the sliding contact particles 10b is 1 μm or more in order to easily maintain the state in which the bearing member 11 does not slide with the surface of the substrate 10a and to further reduce the moving speed of the slurry liquid. Is preferable.

Further, the protruding portion of the sliding contact particles 10b corresponds to a portion of the sliding contact particles 10b other than the fixed portion and the portion removed by processing. For example, in nickel electrodeposition, 60 to 70% of the sliding contact particles 10b are fixed to the sliding contact particles 10b, so that the remaining 30 to 40% of the remaining 30 to 40% is a protruding portion other than the portion removed by processing. Become.

Further, if the protruding height of the sliding contact particles 10b becomes too large, the fixing strength of the sliding contact particles 10b tends to decrease. Therefore, the protruding height of the sliding contact particles 10b is preferably 150 μm or less, more preferably 100 μm or less, and further preferably 60 μm or less.

The surface density, which is the ratio of the area occupied by the sliding contact particles 10b when viewed from the vertical direction of the surface of the substrate 10a, is preferably 20 to 70%. Here, a large surface density means that the distance between the sliding contact particles 10b is narrow, and a small surface density means that the distance between the sliding contact particles 10b is wide. The surface density can be measured using a laser microscope.

By setting the surface density to 20 to 70%, the load applied to each sliding contact particle 10b due to sliding is maintained at an appropriate level, and the slurry liquid to be discharged by the pump is easily released to the interparticle region 12. Further, since the solid substance in the slurry liquid can be easily retained in the interparticle region 12, the force exerted by the solid substance on the bearing member 11 can be reduced, and the wear of the bearing member 11 can be suppressed.

When the surface density is less than 20%, the interparticle region 12 becomes wide, so that it becomes difficult to keep the solid matter in the interparticle region 12. Therefore, it is more preferable to set the surface density to 30% or more, 40% or more, or 50% or more. Further, when the surface density exceeds 70%, the spacing between the sliding contact particles becomes narrow, and it becomes difficult to store water in the interparticle region 12, or it becomes difficult for the stored water to be discharged. Therefore, it is more preferably 60% or less.
<Fixing method of sliding contact particles 10b>
The sliding contact particles 10b may be fixed on the outer surface of the substrate 10a, and the fixing method is not particularly limited. For example, methods such as electrodeposition, brazing, and Spark PlasmaSintering (hereinafter referred to as SPS) can be used.

FIG. 3 is a cross-sectional view showing a state in which the sliding contact particles 10b of the shaft member 10 are electrodeposited on the substrate 10a. Electrodeposition can be performed by a well-known method. For example, first, the sliding contact particles 10b are attached by arranging the powder of the sliding contact particles 10b on the outer surface of the substrate 10a. Then, by energizing in the nickel phosphorus solution, nickel phosphorus is applied to the surface of the substrate 10a. As a result, a part of the sliding contact particles 10b is embedded in the nickel phosphorus film 20 which is a fixing member, and is fixed on the substrate 10a. This method is also referred to as nickel electrodeposition.

When the fixing method is brazing, for example, first, the sliding contact particles 10b are attached by arranging the powder of the sliding contact particles 10b on the outer surface of the substrate 10a. Next, the sliding contact particles 10b are spot-fixed with nickel phosphorus or the like. After that, a paste of brazing material powder made of Ni-Cr-B-Si, Cu-Ag-In-Ti, etc. is applied and heated above the melting point of the brazing material, so that a part of the sliding contact particles 10b becomes the brazing material. It is embedded and fixed on the substrate 10a.

When the fixing method is SPS, for example, first, the powder of the sliding contact particles 10b is placed on the outer surface of the substrate 10a to attach the sliding contact particles 10b. After that, pressure molding is performed with a conventionally known SPS device under the conditions of, for example, 950 ° C. and 30 MPa, and the other sliding contact particles 10b that are not retained on the substrate 10a are removed after the pressure reduction to remove the sliding contact particles. 10b can be fixed on the substrate 10a.

The depth at which the sliding contact particles 10b are embedded in the substrate 10a or the substrate 10a and the fixing member (in other words, the ratio of the fixed portion of the sliding contact particles 10b to the sliding contact particles 10b) is such that the sliding contact particles 10b are the substrate 10a. As long as it is fixed on the outer surface of the particle, it is not particularly limited. When the shaft member 10 includes a fixing member, the ratio of the fixing portion of the sliding contact particles 10b to the sliding contact particles 10b may differ depending on the type of the fixing member.

For example, when the fixing method is electrodeposition, in order to sufficiently fix the sliding contact particles 10b and perform stable sliding, 50% or more of the average particle diameter of the sliding contact particles 10b is a nickel phosphorus film (fixing member). ) Is preferred. On the other hand, when the fixing method is brazing, the sliding contact particles 10b are placed on the substrate 10a by embedding a portion corresponding to 20% or more and less than 60% of the average particle diameter of the sliding contact particles 10b in the brazing material (fixing member). Can be sufficiently fixed to.

That is, brazing is preferable because the sliding contact particles 10b can be strongly fixed on the substrate 10a while reducing the portion of the sliding contact particles 10b that is used for fixing to the substrate 10a. When the sliding contact particles are brazed to the sliding member base, the desired sliding property can be obtained while reducing the amount of expensive sliding contact particles used.

At the tip of each sliding contact particle 10b, that is, at the end on the bearing member 11 side, there is a particle sliding contact surface 13 that is in sliding contact with the bearing member 11. It is preferable that the particle sliding contact surface 13 is on the same circumference about the axis of the shaft member 10 when viewed from the axial direction of the shaft member 10. That is, as shown in FIG. 1, it is preferable that the particle sliding contact surface 13 of each sliding contact particle 10b forms a sliding contact surface 14 between members, which is a circumferential surface centered on the axis of the shaft member 10. The sliding contact surface 14 between the members is in sliding contact with the bearing member 11 which is a sliding member when the shaft member 10 rotates.

According to the above configuration, when the shaft member 10 rotates, only the sliding contact particles 10b are in sliding contact with the bearing member 11. Therefore, the shaft member 10 has a low coefficient of friction and suppresses the generation of heat due to friction, so that the durability is improved.

<Method of forming the particle sliding contact surface 13>
The method of forming the particle sliding contact surface 13 in the sliding contact particles 10b fixed on the substrate 10a in the present embodiment will be described below. Since the particle sliding contact surface 13 is formed by processing the tip of the sliding contact particles 10b, the method for forming the particle sliding contact surface 13 can be said to be, in other words, a processing method for the sliding contact particles 10b.

The particle sliding contact surface 13 of the sliding contact particles 10b fixed on the substrate 10a by the above method is formed so that the particle sliding contact surface 13 is on the same circumference. That is, the distance from the rotation center axis of the substrate 10a to the outermost particle sliding contact surface 13 is made equal so that the particle sliding contact surface 13 of the sliding contact particles 10b is on the same circumference. As a method for forming the particle sliding contact surface 13, a method such as grinding (grinding) or electric discharge machining of the sliding contact particles 10b with a grindstone such as diamond and / or silicon carbide can be used. Those skilled in the art may select an appropriate method for processing a high-hardness material such as the sliding contact particles 10b in the present embodiment.

In the main shaft member 10, (a) the accuracy of fixing the sliding contact particles 10b to the substrate 10a is improved, (b) the dimensional accuracy of the substrate 10a is improved, and (c) the above (a) and / or (b). By determining the average particle diameter of the sliding contact particles 10b in consideration of the described accuracy, etc., the sum of the areas of the particle sliding contact surfaces 13 is 75% when the average value of the sum of the areas is 100%. The particle sliding contact surface 13 is formed so as to be within the range of about 125% (in other words, the sliding contact particles 10b are processed).

Here, the above-mentioned (a) "improving the fixing accuracy of the sliding contact particles 10b to the substrate 10a" means that the sliding contact particles 10b are fixed to the substrate 10a from the outer surface of the substrate 10a before processing. The purpose is to reduce the variation in the distance to the tip of the sliding contact particles 10b between the sliding contact particles 10b. Further, "improving the dimensional accuracy of the substrate 10a" in (b) above means (b-1) reducing the deviation between the center of the outer diameter and the center of the inner diameter of the substrate 10a (shaft sleeve), and (b-1). b-2) To reduce the cylindricity of the substrate 10a, etc.

Regarding the above (b-1), as the diameter (outer diameter) of the substrate 10a becomes larger, the deviation between the center of the outer diameter and the center of the inner diameter of the substrate 10a tends to increase. Further, when the average particle diameter of the sliding contact particles 10b is small, the larger the deviation between the center of the outer diameter and the center of the inner diameter of the substrate 10a, the greater the variation in the area of the particle sliding contact surface 13 between the sliding contact particles 10b. It tends to be large and the area is out of the scope of the present invention. Therefore, as described in (c) above, the average particle diameter of the sliding contact particles 10b to be used is appropriately selected in consideration of the degree of deviation between the center of the outer diameter of the substrate 10a and the center of the inner diameter. The sum of the areas of the contact surfaces 13 can be in the range of 75% to 125% when the average value of the sum of the areas is 100%.

Regarding (b-2) above, when the average particle diameter of the sliding contact particles 10b is small, the larger the cylindricity of the base 10a, that is, the larger the amount of deviation from the geometrically correct cylinder of the base 10a. The more the variation in the area of the particle sliding contact surface 13 between the sliding contact particles 10b becomes large, and the area tends to be out of the range of the present invention. Therefore, as described in (c) above, by appropriately selecting the average particle diameter of the sliding contact particles 10b to be used in consideration of the cylindricity of the substrate 10a, the sum of the areas of the particle sliding contact surfaces 13 is the area. When the average value of the sum is 100%, it can be in the range of 75% to 125%.

<Sliding particles with a coating>
In the sliding member according to the embodiment of the present invention, it is preferable that at least a part of the sliding contact particles is covered with a coating film. According to the above configuration, the corner portion of the tip of the sliding contact particles can be covered with a coating so that the surface becomes a smooth surface, and the sliding contact surface of the sliding member can be made a smooth surface.

In the sliding member according to the embodiment of the present invention, the coating film may cover at least the tips of the sliding contact particles and may be composed of a diamond-like carbon film or a glassy carbon film.

According to the above configuration, the corners of the tips of the sliding contact particles can be covered with a coating film made of a diamond-like carbon film or a glassy carbon film so that the surface becomes a smooth surface, and the sliding contact surface of the shaft member can be covered. It can be made smoother.

In the sliding member according to the embodiment of the present invention, the coating film is made of a diamond-like carbon film or a glassy carbon film that covers the periphery of the tip surface, and is a portion corresponding to a corner portion from the tip surface to the side surface. The outer surface of the coating film may be curved.

According to the above configuration, the coating film made of a diamond-like carbon film or a glassy carbon film covers the periphery of the tip surface of the sliding contact particles and corresponds to the corner portion from the tip surface to the side surface of the sliding contact particles. The outer surface is curved. Therefore, the smoothness of the sliding contact surface of the sliding member can be further improved, and the aggression of the corner portion to the sliding surface can be alleviated.

The film thickness of the coating is preferably 5 μm to 10 μm in order to fully enjoy the effect of the coating.

When at least a part of the sliding contact particles is covered with a coating, and when the tip of the sliding contact particles, that is, at least a part of the particle sliding contact surface is covered with a coating, the sliding contact is performed. The protruding height of the particles is the height from the surface of the base of the sliding member to the tip of the coating.

<Method of forming the particle sliding contact surface of the sliding contact particles having a coating>
The particle sliding contact surface of the sliding contact particles having a coating film can be formed by the following two methods.

The first forming method is a method including the following steps in order: (1) a step of fixing the sliding contact particles on the outer surface of the sliding member base by the above-mentioned method; (2) by the above-mentioned method. The step of processing the tip of the sliding contact particles fixed in the step (1) above to form the particle sliding contact surface; and (3) forming a coating film so that at least a part of the particle sliding contact surface is covered. Process to do.

The second forming method is a method including the following steps in order: (1) a step of fixing the sliding contact particles on the outer surface of the sliding member base by the above-mentioned method; (2) by the above-mentioned method. A step of forming a film so that at least a part of the tip surface of the sliding contact particles fixed in the step (1) is covered; and (3) at least a part obtained in the step (1) above. A process of processing sliding contact particles whose tip surface is covered to form a particle sliding contact surface.

<Method of forming a film>
The sliding contact particles in which at least a part of the sliding contact particles is coated with a diamond-like carbon film (hereinafter, also referred to as a DLC film) can be adjusted by coating the sliding contact particles with a DLC film. As a method for coating a DLC film, a method by a vapor deposition technique using plasma in vacuum or atmospheric pressure, a method of electrically precipitating a carbon film from a liquid such as an organic solvent, and the like are known. Currently, the coating method by the vapor deposition method using a vacuum device is the mainstream.

The method of coating a DLC film by a vapor deposition method using a vacuum device is roughly classified into a method of using solid carbon as a carbon supply source and a method of using a hydrocarbon-based raw material. Arc ion plating, non-equilibrium magnetron sputtering, and filtered arc ion plating are known as methods using solid carbon (graphite) as a carbon source. In addition, as a method using a hydrocarbon gas (CH ₄ , C ₆ H ₆ , C ₂ H ₂ , etc.) as a carbon supply source, high-frequency plasma CVD, pulsed DC plasma CVD, ionization vapor deposition, and plasma ion implantation / deposition are performed. It has been known.

For the sliding contact particles in which at least a part of the sliding contact particles is coated with a glassy carbon film, the glassy carbon resin composition containing a thermosetting resin as a main component is applied to the sliding contact particles and then cured. It can be adjusted by firing and carbonizing in an inert atmosphere or under vacuum.

<Sliding member>
Next, a bearing member (sliding member) that slides relative to the shaft member (sliding member) according to the above-described aspect of the present invention will be described with reference to FIG. In the present embodiment, as shown in FIG. 1, the bearing member 11 has a cylindrical shape in which the shaft member 10 is housed, and supports the shaft member 10.

The material of the bearing member 11 is, for example, made of hard ceramics, cemented carbide, or the like, and is preferably ceramics or cermet. This makes it possible to improve the durability of the member to be slid. It is preferable that the unevenness of the surface of the inner surface of the bearing member 11 does not reach the region depth between the sliding contact particles in the shaft member 10 which is a sliding member, but when the surface roughness Ra is 1.0 μm or less. There is no problem because it does not affect friction so much. The surface of the bearing member 11 may be processed to form a sintered body or a film for lowering the coefficient of friction or improving wear resistance.

[2. Shaft / bearing structure]
The sliding member has been described above by taking as an example the case where it is used for a shaft / bearing structure having a shaft and a bearing. That is, the sliding member according to one aspect of the present invention is used for a shaft / bearing structure having a shaft and a bearing, and the particle sliding contact surface is on the same circumference centered on the shaft of the shaft / bearing structure. It may have a certain configuration.

According to the above configuration, when the sliding member is used in a pump shaft / bearing structure composed of the sliding member and the sliding member, the sliding member comes into sliding contact with the sliding member when the sliding member rotates. Only the sliding particles. Therefore, the sliding member has a low coefficient of friction, heat generation due to friction is suppressed, and the durability of the material is improved.

[3. Leading standby operation pump]
The sliding member according to one aspect of the present invention can be suitably used for a preceding standby operation pump. The preceding standby operation pump provided with this sliding member is capable of stable operation because wear of the sliding member is suppressed, and therefore can be a preceding standby operation pump having excellent durability.

[Reciprocating sliding test]
Single crystal diamond particles (hereinafter, also referred to as diamond particles) having an average particle diameter of 100 μm as sliding contact particles are nickel-electric on the outer surface of a SUS304 material (cylindrical shape) having an outer diameter of 80 mm × an inner diameter of 70 mm × 100 mm L as a sliding member base. The shaft sleeve (sliding member) was manufactured by wearing and fixing it.

Next, the diamond particles are ground to form a particle sliding contact surface at the tip of the diamond particles so that the particle sliding contact surface exists on the same circumference centered on the sliding member base. did.

Then, a chip in the range of 60 mm × 10 mm × thickness 5 mm (test surface is 60 mm × 10 mm) was cut out from the shaft sleeve after forming the particle sliding contact surface, and a disk was produced using the chip. A reciprocating sliding test was carried out by sliding a silicon nitride pin having a diameter of 5 mm × 25 mm L and a disk at a peripheral speed of 0.5 m / sec for 2 hours.

Here, a plurality of the above discs were prepared, and the reciprocating sliding test was carried out for each disc at different surface pressures. At this time, a reciprocating sliding test was carried out under the condition that there was no lubricant between the disk and the silicon nitride pin. The shaft sleeve and the tip are sliding members in one aspect of the present invention, and the silicon nitride pin is a sliding member.

After the reciprocating sliding test at each surface pressure, the amount of wear of the silicon nitride pin was measured using a laser microscope (Model VK-9700 manufactured by KEYENCE CORPORATION). The results of the reciprocating sliding test are shown in FIG.

FIG. 4 is a graph showing the relationship between the surface pressure and the amount of wear in the reciprocating sliding test. The horizontal axis shows the surface pressure (N / mm ² ), and the vertical axis shows the amount of wear (order: ^10-7 , unit: μm). An approximate straight line was created from the plot of the amount of wear with respect to the surface pressure.

From FIG. 4, it was found that there is a positive correlation between the surface pressure and the amount of wear. That is, it was found that the amount of wear increases as the surface pressure increases.

[Relationship between the inner diameter of the shaft sleeve and the average particle diameter of the sliding contact particles]
(Manufacturing Example 1)
Single crystal diamond particles (hereinafter, also referred to as diamond particles) having various average particle diameters as sliding contact particles are fixed by nickel electrodeposition on the surface of a SUS304 material having a diameter of 85 mm × 100 mL as a sliding member base, and a shaft is formed. A sleeve (sliding member) was manufactured. Here, by electrodeposition, 60% of the average particle size of the diamond particles was embedded in the nickel phosphorus film.

Next, the diamond particles are ground to form a particle sliding contact surface at the tip of the diamond particles so that the particle sliding contact surface exists on the same circumference centered on the sliding member base. did. Here, the grinding process was performed with the aim of removing a portion corresponding to a length of 30% of the average particle diameter of the diamond particles from the protruding tip of the diamond particles before processing.

After that, the protrusion height (μm) of the shaft sleeve on which the particle sliding contact surface was formed was measured using a laser microscope (Keyence, model VK-9700), and the minimum protrusion height and the maximum protrusion height were shown. Shown in 1. Further, the unit surface (1 mm × 1 mm) was set at a total of 80 locations (10 × 8) of the shaft sleeve at 10 locations in the circumferential direction and 8 locations in the axial direction. The surface of each unit was observed using a laser microscope, and a micrograph was taken. Then, based on the photograph, the average value (mean area value) of the sum of the areas of the particle sliding contact surfaces was obtained. Further, among the 80 unit surfaces, the ratios of the minimum value and the maximum value when the average value is 100% are calculated for the minimum value and the maximum value of the sum of the areas of the particle sliding contact surfaces, and the minimum value is calculated. The area ratio ratio (%) and the maximum area ratio ratio (%) were used.

Table 1 shows the average particle size of the sliding contact particles used, as well as the minimum protrusion height, maximum protrusion height, average area value (mm ² ), minimum area ratio, and maximum area ratio.

(Manufacturing Example 2)
Electroplation (nickel electrodeposition of single crystal diamond particles) and formation of particle sliding contact surface (sliding) under the same conditions as in Production Example 1 except that a SUS304 material having a diameter of 164 mm × 100 mL was used as the base of the sliding member. Grinding of contact particles) was performed.

Then, the protrusion height (μm) is measured by the same method as in Production Example 1, the average value of the sum of the areas of the particle sliding contact surfaces is obtained, and the minimum area ratio (%) and the maximum area ratio (%) are obtained. Was calculated.

Table 2 shows the average particle size of the sliding contact particles used, as well as the minimum protrusion height, maximum protrusion height, minimum area ratio, and maximum area ratio.

From Tables 1 and 2, it was found that the minimum protrusion height, the maximum protrusion height, and the minimum area ratio ratio increased and the maximum area ratio ratio decreased, depending on the increase in the average particle size of the sliding contact particles. That is, when sliding contact particles having a large average particle diameter are used, there are variations in materials or processing in the manufacture of the shaft sleeve having the particle sliding contact surface (for example, fixing the sliding contact particles to the base of the sliding member, and fixing the sliding contact particles to the base of the sliding member. / Or the influence of the dimensional variation of the base of the sliding member can be mitigated.

INDUSTRIAL APPLICABILITY The present invention can be used for a preceding standby operation pump that operates under harsh conditions for the shaft / bearing structure, such as preceding operation in an anhydrous state and drainage in a gas-liquid mixed state of a slurry containing earth and sand. ..

1A Shaft / Bearing structure 10 Shaft member (sliding member)
10a Substrate (sliding member base)
10b Sliding particles 11 Bearing member (sliding member)
12 Inter-particle region 13 Particle sliding contact surface 14 Inter-member sliding contact surface 20 Nickel phosphorus film

Claims (8)

A sliding member that slides relative to the sliding member.
Sliding member base and
It is provided with sliding contact particles scattered and fixed on the surface of the sliding member base.
The above sliding particles are
It has a particle sliding contact surface that protrudes from the surface of the sliding member base and is in sliding contact with the sliding member.
The sum of the areas of the particle sliding contact surfaces per unit surface area measured by the sliding member base is the sum of the areas of the particle sliding contact surfaces per at least two or more unit surface areas of the sliding member base. A sliding member, characterized in that it is in the range of 78% to 114% when the average value is 100%. The sliding member according to claim 1, wherein the surface density, which is the ratio of the area occupied by the sliding contact particles, is 20 to 70% when viewed from the vertical direction of the surface of the sliding member base. .. The sliding member according to claim 1 or 2, wherein the average particle diameter of the sliding contact particles is 10 to 250 μm. The sliding according to any one of claims 1 to 3, wherein the average height of the sliding contact particles from the surface of the sliding member base to the particle sliding contact surface is 0.8 μm or more. Moving member. The sliding contact particles are at least one of diamond particles, diamond-like carbon particles, cubic boron nitride, glassy carbon particles, alumina particles, boron carbide particles, silicon carbide particles, tungsten carbide particles, silicon nitride particles and molybdenum carbide particles. The sliding member according to any one of claims 1 to 4, wherein the sliding member includes one or more of them. Used for shaft / bearing structures with shafts and bearings
The sliding member according to any one of claims 1 to 5, wherein the particle sliding contact surface is on the same circumference about the axis of the shaft / bearing structure. The sliding member according to any one of claims 1 to 6, wherein the sliding contact particles are at least partially covered with a coating film. The base of the sliding member is a cylindrical shaft sleeve.
When the diameter of the shaft sleeve is 85 mm, the average particle diameter of the sliding contact particles is 53 to 105 μm, while the diameter is 53 to 105 μm.
The sliding member according to claim 3, wherein when the diameter of the shaft sleeve is 164 mm, the average particle diameter of the sliding contact particles is 105 to 150 μm.

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