阅读说明：本技术 滑动部件 (Sliding component ) 是由 丸冈俊和 于 2019-02-04 设计创作，主要内容包括：本发明提供一种即使不对滑动面进行表面处理、在滑动时耐磨损性也优异、并且具有稳定且高的摩擦系数的滑动部件。该滑动部件为将树脂组合物成型而成的滑动部件,该滑动部件的特征在于：树脂组合物含有：聚酰胺树脂；拉伸弹性模量为190GPa～600GPa的纤维状加强材料；和聚酰胺系弹性体。(The invention provides a sliding member which has excellent abrasion resistance during sliding and has a stable and high friction coefficient even if the sliding surface is not subjected to surface treatment. The sliding member is formed by molding a resin composition, and is characterized in that: the resin composition contains: a polyamide resin; a fibrous reinforcing material having a tensile elastic modulus of 190GPa to 600 GPa; and a polyamide-based elastomer.)

1. A sliding member obtained by molding a resin composition, characterized in that:

the resin composition contains: a polyamide resin; a fibrous reinforcing material having a tensile elastic modulus of 190GPa to 600 GPa; and a polyamide-based elastomer.

2. The sliding member according to claim 1, wherein:

the fibrous reinforcing material has an average fiber length of 0.1 to 10mm and an average fiber diameter of 0.5 to 30 μm.

3. The sliding member according to claim 1 or 2, wherein:

the fibrous reinforcing material is carbon fiber.

4. A sliding member according to any one of claims 1 to 3, wherein:

the content of the fibrous reinforcing material in 100% by mass of the total amount of the resin composition is 1% by mass to 40% by mass.

5. The sliding member according to any one of claims 1 to 4, wherein:

the polyamide elastomer content is 1 to 20 mass% based on 100 mass% of the total resin composition.

6. The sliding member according to any one of claims 1 to 5, wherein:

the resin composition further contains non-fibrous titanic acid compound particles.

7. The sliding member according to claim 6, wherein:

the content of the non-fibrous titanic acid compound particles is 1 to 10 mass% with respect to 100 mass% of the total amount of the resin composition.

8. The sliding member according to any one of claims 1 to 7, wherein:

the friction coefficient with the carbon steel material S45C is more than 0.40 under the conditions that the surface pressure is 0.8MPa and the circumferential speed is 0.16 m/S.

9. The sliding member according to any one of claims 1 to 8, wherein:

the ring-shaped member is used in slidable contact with a ring-shaped target member.

Technical Field

The present invention relates to a sliding member.

Background

A torque fluctuation absorbing apparatus for a vehicle such as an automobile is an apparatus that is disposed in a power transmission path between a power source such as an engine or an electric motor and a transmission and absorbs (reduces or suppresses) a fluctuation torque between the power source and the transmission. There is a device having, as a basic configuration of a torque fluctuation absorbing device, the following components: a damper for absorbing a fluctuating torque by a spring force; a hysteresis part that absorbs (suppresses) the fluctuation torque by utilizing a hysteresis (hysteresis) torque of friction; and a restricting portion that generates a slip when the torsion of the rotating shaft cannot be absorbed by the damper portion or the hysteresis portion. In the hysteresis part, a thrust member (a bush, a friction member) provided between the two rotating members in the axial direction is pressed against one rotating member by a disc spring, and when torsion occurs between the two rotating members, a hysteresis torque by a friction force is generated between the thrust member and the one rotating member, thereby absorbing a fluctuation torque. As a conventional technique of such a torque fluctuation absorbing device, patent document 1 and patent document 2 are known.

Disclosure of Invention

Technical problem to be solved by the invention

The thrust member is often used by injection molding a thermoplastic resin for cost reduction and weight reduction. Further, the thrust member is required to have low wear resistance (wear resistance) and a high and stable friction coefficient (μ) as friction characteristics during sliding. However, a thrust member made of a thermoplastic resin is used after a sliding surface is subjected to surface treatment (plating, metal coating, or the like) because of poor wear resistance and unstable friction coefficient.

The present invention has been made in view of the above circumstances, and has as its main object: provided is a sliding member which has excellent wear resistance during sliding and has a stable and high coefficient of friction without surface treatment of the sliding surface.

Technical solution for solving technical problem

The present inventors have conducted extensive studies to solve the above problems, and as a result, the present invention has been completed. That is, the gist of the present invention is as follows.

The sliding member according to item 1, which is a sliding member obtained by molding a resin composition, is characterized in that: the resin composition comprises: a polyamide resin; a fibrous reinforcing material having a tensile elastic modulus of 190GPa to 600 GPa; and a polyamide-based elastomer.

The sliding component according to item 1, wherein the fibrous reinforcing material has an average fiber length of 0.1mm to 10mm and an average fiber diameter of 0.5 μm to 30 μm.

The sliding component according to item 1 or item 2, wherein the fibrous reinforcing material is carbon fiber.

The sliding component according to any one of claims 1 to 3, wherein a content of the fibrous reinforcing material in 100% by mass of the total amount of the resin composition is 1% by mass to 40% by mass.

The sliding member according to any one of claims 1 to 4, wherein the content of the polyamide elastomer is 1 to 20% by mass based on 100% by mass of the total amount of the resin composition.

The sliding member according to any one of claims 1 to 5, wherein the resin composition further contains non-fibrous titanic acid compound particles.

The sliding component according to item 7, 6, wherein a content of the non-fibrous titanic acid compound particles in 100% by mass of a total amount of the resin composition is 1% by mass to 10% by mass.

The sliding component according to any one of claims 1 to 7, wherein the friction coefficient with the carbon steel material S45C is 0.40 or more under the conditions of a surface pressure of 0.8MPa and a circumferential speed of 0.16 m/sec.

The sliding component according to any one of claims 1 to 8, wherein the sliding component is an annular component that is used in slidable contact with an annular target component.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a sliding member having excellent wear resistance during sliding and a stable and high coefficient of friction can be provided without surface treatment of the sliding surface.

Detailed Description

An example of a preferred embodiment for carrying out the present invention will be described below. However, the following embodiments are merely examples. The present invention is not limited to the following embodiments.

The sliding member of the present invention is a sliding member obtained by molding a resin composition, and is characterized in that: the resin composition contains: a polyamide resin; a fibrous reinforcing material having a tensile elastic modulus of 190GPa to 600 GPa; and a polyamide-based elastomer.

The sliding member of the present invention has the above-described structure, and therefore, even if the sliding surface is not surface-treated, it has excellent wear resistance during sliding and a stable and high coefficient of friction. In particular, the sliding member of the present invention has a coefficient of friction of 0.40 or more with the carbon steel material S45C. As described above, the sliding member of the present invention has a friction coefficient of 0.40 or more with the carbon steel material S45C, and therefore can be suitably used as a thrust member for a torque fluctuation absorbing device, and the friction coefficient is preferably 1.00 or less, more preferably 0.80 or less, from the viewpoint of further improving stability. The above friction coefficient is: the average value of the friction coefficient measured in the frictional wear test according to JIS K7218A was determined under the conditions of 0.8MPa of surface pressure and 0.16 m/sec of peripheral velocity, using a ring-shaped article (hollow cylinder having an outer diameter of 25.6mm, an inner diameter of 20mm, and a height of 15 mm) obtained by injection molding of the resin composition described later and a ring (hollow cylinder having an outer diameter of 25.6mm, an inner diameter of 20mm, and a height of 15 mm) of carbon steel S45C. S45C is a material symbol in JIS which indicates a carbon steel for machine structural use.

Hereinafter, each constituent element and the like of the sliding member of the present invention will be described.

< resin composition >

The resin composition used in the present invention contains: a polyamide resin; a fibrous reinforcing material having a tensile elastic modulus of 190GPa to 600 GPa; and a polyamide elastomer, and may contain other additives as required.

(Polyamide resin)

The polyamide resin used in the present invention is a polymer having an amide bond (-NH — C (═ O) -) in the main chain, and is a polymer containing a structural unit derived from a monomer component such as an aminocarboxylic acid, a diamine, or a dicarboxylic acid, which will be described later. The polyamide resin may be a polyamide resin composed of 1 kind of structural unit (a polymer of an aminocarboxylic acid), or a polyamide resin composed of a plurality of kinds of structural units (a copolymer of a diamine and a dicarboxylic acid, a copolymer of a diamine and a dicarboxylic acid and an aminocarboxylic acid, or the like). In the case of a copolymer composed of a plurality of kinds of structural units, the copolymerization ratio, the copolymerization system (random copolymer, block copolymer, alternating copolymer, etc.), and the like can be arbitrarily selected.

Examples of the aminocarboxylic acid include aliphatic ω -aminocarboxylic acids having 5 to 20 carbon atoms such as 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminocaprylic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like; aromatic diamines such as p-aminobenzoic acid and p-aminomethylbenzoic acid. In addition, cyclic lactams corresponding to aliphatic omega-aminocarboxylic acids can also be used. These can be used alone, or more than 2 kinds of them can be used in combination.

Examples of diamines include: aliphatic diamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 1, 7-diaminoheptane, 1, 8-diaminooctane, 1, 9-diaminononane, 1, 10-diaminodecane, 1, 11-diaminoundecane, 1, 12-diaminododecane, 2-methyl-1, 5-diaminopentane, 3-methyl-1, 5-diaminopentane, and 2-ethyltetramethylenediamine; alicyclic diamines such as 1, 2-diaminocyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, 1, 3-bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl) methane, 4 '-diamino-3, 3' -dimethyldicyclohexylmethane, isophoronediamine, and piperazine; and aromatic diamines such as p-phenylenediamine, o-phenylenediamine, m-phenylenediamine, p-xylylenediamine, o-xylylenediamine, and m-xylylenediamine. These can be used alone, or more than 2 kinds of them can be used in combination.

Examples of dicarboxylic acids include: aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1, 9-azelaic acid, 1, 10-sebacic acid, and 1, 11-undecanedicarboxylic acid; alicyclic dicarboxylic acids such as 1, 2-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, and 1, 4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2-methyl terephthalic acid, and naphthalenedicarboxylic acid. These can be used alone, or more than 2 kinds of them can be used in combination.

Specific examples of the polyamide resin include: aliphatic polyamide resins of polyamide 6 (polymer of 6-aminocaproic acid), polyamide 66 (copolymer of hexamethylenediamine and adipic acid), polyamide 11 (polymer of 11-aminoundecanoic acid), polyamide 12 (polymer of 12-aminododecanoic acid), polyamide 46 (copolymer of tetramethylenediamine and adipic acid), polyamide 6/66 copolymer (copolymer of 6-aminocaproic acid and hexamethylenediamine and adipic acid), polyamide 6/12 copolymer (copolymer of 6-aminocaproic acid and 12-aminododecanoic acid); semi-aromatic polyamide resins such as polyamide MXD6 (a copolymer of m-xylylenediamine and adipic acid), polyamide MXD10 (a copolymer of m-xylylenediamine and sebacic acid), polyamide 6T (a copolymer of hexamethylenediamine and terephthalic acid), polyamide 9T (a copolymer of 1, 9-diaminononane and terephthalic acid), polyamide 10T (a copolymer of 1, 10-diaminodecane and terephthalic acid), and polyamide 6T/66 copolymer (a copolymer of hexamethylenediamine, terephthalic acid and adipic acid). These can be used alone, or more than 2 kinds of them can be used in combination.

In the present invention, the semi-aromatic polyamide resin means: the polyamide resin contains a structural unit derived from an aliphatic monomer and a structural unit derived from an aromatic monomer as structural units of the polyamide resin. The aliphatic monomer includes, among the above monomer components, aliphatic dicarboxylic acids, aliphatic diamines, alicyclic diamines, aliphatic ω -aminocarboxylic acids, alicyclic dicarboxylic acids, and the like. The aromatic monomer includes, among the above monomer components, aromatic diamine, aromatic dicarboxylic acid, aromatic aminocarboxylic acid, and the like.

The melting point of the polyamide resin used in the present invention is preferably 150 ℃ or higher in order to further suppress deformation, discoloration, and the like. In order to further suppress thermal decomposition of the polyamide resin during melt processing such as extrusion and molding, the melting point is preferably 350 ℃ or lower, and more preferably 330 ℃ or lower. The melting point can be measured according to JIS-K7121.

The shape of the polyamide resin is not particularly limited as long as it can be melt-kneaded, and any of powder, pellet, and pellet shapes can be used.

The content of the polyamide resin in the resin composition is preferably 30 to 97% by mass, more preferably 42 to 94% by mass, and still more preferably 65 to 91% by mass, based on 100% by mass of the total amount of the resin composition.

(fibrous reinforcing Material)

The tensile modulus of the fibrous reinforcing material used in the present invention is 190GPa to 600GPa, preferably 200GPa to 450GPa, and more preferably 200GPa to 300 GPa. When the tensile elastic modulus of the fibrous reinforcing material is too small, the effect of reinforcing the sliding interface by the fibrous reinforcing material is small, and the friction powder is excessively generated, and the friction coefficient may become unstable. On the other hand, when the tensile elastic modulus is too large, the substance released to the sliding interface may become a large resistance. Therefore, it is considered that when the tensile elastic modulus is in the above range, the fibrous reinforcing material is appropriately ground at the sliding interface, and the friction coefficient is high and stable. The tensile modulus of elasticity of the fibrous reinforcing material is a value measured according to method a of JIS R7606 (2000).

The fibrous reinforcing material is not particularly limited, and carbon fiber, glass fiber, potassium titanate fiber, wollastonite fiber, aramid fiber, alumina fiber, silicon carbide fiber (silicon carbide fiber), boron fiber, silicon carbide fiber, Polyphenylene Benzoxazole (PBO) fiber, and the like can be used, and a substance having the tensile modulus of elasticity described above can be used alone or in combination of a plurality of substances. Among these, carbon fibers are preferable, and for example, Polyacrylonitrile (PAN), pitch, cellulose, vapor phase grown carbon fibers using hydrocarbon, graphite fibers, and the like can be used, and these may be used alone or in combination of 2 or more. Among these, PAN-based carbon fibers are preferable.

The average fiber length of the fibrous reinforcing material used in the present invention is preferably 0.1 to 10mm, more preferably 1 to 8mm, and further preferably 4 to 7 mm. The fibrous reinforcing material may be one that forms bundles of the fibrous reinforcing material by aggregation with a bundling agent or the like, and the average fiber diameter is preferably 0.5 to 30 μm, more preferably 1 to 20 μm, and still more preferably 3 to 15 μm. The average aspect ratio (average fiber length/average fiber diameter) is preferably 5 or more, more preferably 10 or more, further preferably 20 or more, and particularly preferably 50 or more. By using such short fibers (chopped fibers) as a reinforcing material, a resin composition having further balanced moldability and mechanical properties can be obtained.

The content of the fibrous reinforcing material in the resin composition is preferably 1 to 40% by mass, more preferably 3 to 30% by mass, and still more preferably 5 to 20% by mass, based on 100% by mass of the total amount of the resin composition. When the content of the fibrous reinforcing material is too small, it is difficult to obtain the reinforcing effect, and when the content of the fibrous reinforcing material is too large, the abrasion resistance may be lowered.

(Polyamide elastomer)

The polyamide elastomer used in the present invention is a thermoplastic elastomer having a polyamide segment as a hard segment and a polyether segment as a soft segment. Examples of the polyamide-based elastomer include a polyether ester amide elastomer in which a hard segment and a soft segment are connected to each other via an ester bond, a polyether amide elastomer in which a hard segment and a soft segment are connected to each other via an amide bond, and the like, and a polyether amide elastomer is preferable. By using the polyamide elastomer, the friction coefficient can be stabilized without lowering the abrasion resistance.

The polyamide segment is a segment having an amide bond (-NH — C (═ O) -) in the main chain, and is a segment containing a structural unit derived from a monomer component such as an aminocarboxylic acid, a diamine, or a dicarboxylic acid, which will be described later. The polyamide segment may be a segment composed of 1 kind of structural unit (polymer of aminocarboxylic acid) or a segment composed of a plurality of kinds of structural units (copolymer of diamine and dicarboxylic acid, copolymer of diamine, dicarboxylic acid, and aminocarboxylic acid, etc.). In the case of a copolymer composed of a plurality of kinds of structural units, the copolymerization ratio, the copolymerization system (random copolymer, block copolymer, alternating copolymer, etc.), and the like can be arbitrarily selected.

Examples of the aminocarboxylic acid include aliphatic ω -aminocarboxylic acids having 5 to 20 carbon atoms such as 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminocaprylic acid, 10-aminocaprylic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. In addition, cyclic lactams corresponding to these can also be used. These can be used alone, or more than 2 kinds of them can be used in combination.

Examples of the diamine include aliphatic diamines having 2 to 20 carbon atoms such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2, 4-trimethylhexamethylenediamine, 2,4, 4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine and the like. These can be used alone, or more than 2 kinds of them can be used in combination.

Examples of dicarboxylic acids include: linear aliphatic dicarboxylic acids having 2 to 20 carbon atoms such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid; dimerized aliphatic dicarboxylic acids having 14 to 48 carbon atoms (dimer acids) obtained by dimerizing unsaturated fatty acids obtained by fractionation of triglycerides, and hydrides thereof (hydrogenated dimer acids); alicyclic dicarboxylic acids such as 1, 4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and the like.

Among these, 11-aminoundecanoic acid or 12-aminododecanoic acid is preferable as the monomer component, particularly from the viewpoint of further improving dimensional stability, chemical resistance and mechanical properties due to low water absorption.

The number average molecular weight of the polyamide segment is preferably 300 to 15000, and more preferably 300 to 6000 from the viewpoint of further improving flexibility and moldability. In the present specification, the number average molecular weight is a number average molecular weight (Mn) in terms of polystyrene measured by Gel Permeation Chromatography (GPC).

The polyether segment is a segment having an ether bond (-O-) in the main chain, and examples thereof include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, ABA type triblock polyether represented by the following formula (1), and the like, and these may be used alone or in 2 or more kinds. Further, polyether diamine obtained by reacting an end of polyether with ammonia or the like can be used. The number average molecular weight of the soft segment is preferably 200 to 6000, more preferably 650 to 2000.

(in the formula (1), x represents 1-20, y represents 4-50, and z represents 1-20.)

In the formula (1), x is an integer of 1 to 20, preferably an integer of 1 to 18, more preferably an integer of 1 to 16, particularly preferably an integer of 1 to 14, and most preferably an integer of 1 to 12. y is an integer of 4 to 50, preferably an integer of 5 to 45, more preferably an integer of 6 to 40, particularly preferably an integer of 7 to 35, and most preferably an integer of 8 to 30. z is an integer of 1 to 20, preferably an integer of 1 to 18, more preferably an integer of 1 to 16, particularly preferably an integer of 1 to 14, and most preferably an integer of 1 to 12.

The combination of the polyamide segment and the polyether segment includes various combinations of the polyamide segment and the polyether segment described above. Among these, a combination of a polymer of 12-aminododecanoic acid/polyethylene glycol, a combination of a polymer of 12-aminododecanoic acid/polypropylene glycol, a combination of a polymer of 12-aminododecanoic acid/polytetramethylene ether glycol, and a combination of a polymer of 12-aminododecanoic acid/ABA type triblock polyether are preferable, and a combination of a polycondensate of 12-aminododecanoic acid/ABA type triblock polyether is particularly preferable.

The ratio (mass ratio) of the polyamide segment to the polyether segment is preferably 95/5 to 20/80, more preferably 60/40 to 30/70, and particularly preferably 50/50 to 30/70. When the content of the polyamide segment is less than 20% by mass, bleeding from the molded article tends to occur, and when it exceeds 95% by mass, the flexibility tends to be insufficient.

The melting point of the polyamide elastomer is preferably 130 ℃ or higher in order to further suppress deformation, discoloration, and the like. In addition, in order to further suppress thermal decomposition of the polyamide elastomer during melt processing such as extrusion and molding, the melting point is preferably 320 ℃ or lower, and more preferably 270 ℃ or lower. The melting point can be measured according to JIS-K7121.

The shape of the polyamide elastomer is not particularly limited as long as it can be melt-kneaded, and any of powder, pellet, and pellet forms can be used.

The content of the polyamide elastomer in the resin composition is preferably 1 to 20 mass%, more preferably 2 to 15 mass%, and still more preferably 3 to 10 mass% of the total amount 100 mass% of the resin composition. When the content of the polyamide-based elastomer is too small, it is difficult to obtain the desired effect, and when the content of the polyamide-based elastomer is large, the heat resistance may be lowered.

(other additives)

The resin composition used in the present invention may contain, in addition to the polyamide resin, fibrous reinforcing material, and polyamide elastomer, non-fibrous titanic acid compound particles, and other additives, as required.

As the non-fibrous titanic acid compound particles, a titanic acid metal compound containing at least one metal element selected from alkali metals, alkaline earth metals, and earth metals can be used. Examples of the alkali metal include lithium, sodium, potassium, rubidium, cesium, and francium, and preferably lithium, sodium, and potassium. Examples of the alkaline earth metal include beryllium, magnesium, calcium, strontium, barium, and radium, and preferably magnesium and calcium. As the earth metal, aluminum may be mentioned.

Specific examples of the metal titanate compound include, for example, compounds represented by the formula A₂Ti_nO_(2n+1)[ wherein A is 1 or 2 or more selected from alkali metals, n is 2 to 8 ], R_xM_yTi_(2-y)O₄Wherein R is an alkali metal other than lithium,m is 1 or more than 2 selected from lithium, magnesium, zinc, nickel, copper, iron, aluminum, gallium and manganese, x is 0.5-1.0, y is 0.25-1.0, and K can be substituted_0.5～0.8Li_0.27Ti_1.73O_3.85～3.95Lithium potassium titanate, can be represented by K_0.2～0.8Mg_0.4Ti_1.6O_3.7～3.95Potassium magnesium titanate represented by₂TiO₅Aluminum titanate shown, and the like. Among these, aluminum titanate is preferable.

The particle shape of the metal titanate particles may be any particle selected from known metal titanate particles as long as it is in a non-fibrous form such as a sphere, a plate, a column, or a block. The shape of the metal titanate compound particles can be analyzed by observation with a scanning electron microscope, for example.

In the present invention, the fibrous particles mean: when the longest side of a cuboid (circumscribed cuboid) having the smallest volume among the cuboids circumscribed with the particles is defined as a long diameter L, the second longest side is defined as a short diameter B, and the shortest side is defined as a thickness T (B > T), L/B and L/T are both 5 or more particles, and the long diameter L corresponds to the fiber length and the short diameter B corresponds to the fiber diameter. In addition, non-fibrous particles refer to particles other than fibrous particles, meaning: and particles having a L/B of less than 5, wherein the longest side of a cuboid having the smallest volume (circumscribed cuboid) among cuboids circumscribed with the particles is defined as a long diameter L, the second longest side is defined as a short diameter B, and the shortest side is defined as a thickness T (B > T).

The average particle diameter of the particles of the metal titanate compound is preferably more than 5 μm, more preferably more than 50 μm and less than 500. mu.m, still more preferably more than 100 μm and less than 450. mu.m, and particularly preferably more than 200 μm and less than 400. mu.m.

The average particle diameter of the metal titanate compound particles can be measured by a laser diffraction/scattering method, and is a particle diameter at 50% volume basis cumulative particle diameter (50% volume basis cumulative particle diameter) in a particle size distribution measured by a laser diffraction/scattering method, that is, D₅₀(median diameter). The volume-based cumulative 50% particle diameter (D)₅₀) Comprises the following steps: the particle size distribution is determined on the basis of the volume, and the whole volume is setThe cumulative particle size at the point where the cumulative value reached 50% when the number of particles counted from the side where the particle size was small was found in the cumulative curve of 100%.

The content of the non-fibrous metal titanate compound particles in the resin composition is preferably 1 to 10% by mass, more preferably 1 to 8% by mass, and still more preferably 1 to 5% by mass, based on 100% by mass of the total amount of the resin composition. By setting the blending amount of the non-fibrous titanic acid metal compound particles to the above range, the friction coefficient of the sliding member can be further improved.

As other additives, there may be mentioned: pigments such as carbon black and titanium oxide, and colorants such as dyes; solid lubricants such as graphite, molybdenum disulfide, tungsten disulfide, Boron Nitride (BN), Polytetrafluoroethylene (PTFE), low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ultrahigh-molecular polyethylene; a fluidity improver; release agents such as saturated fatty acid esters, unsaturated fatty acid esters, and polyolefin waxes; heat-conducting agents such as polyether ester amide and glycerol monostearate; conductivity-imparting agents such as carbon-based conductive agents, metal oxide-based conductive agents, and surfactants; antistatic agents such as polyether ester amide and glycerol monostearate; a nucleating agent; anti-aging agents (antioxidants); ultraviolet absorbers such as benzophenone-based compounds, benzotriazole-based compounds, hydroxyphenyltriazine-based compounds, cyclic imino ester-based compounds, and cyanoacrylate-based compounds; flame retardants such as halogen (bromine and chlorine compounds), antimony compounds, magnesium hydroxide, aluminum hydroxide, phosphoric acid esters, condensed phosphoric acid esters, inorganic phosphorus flame retardants, and phosphazene compounds; a dripping-preventing agent; inorganic fillers such as calcium carbonate, mica (mica), sericite, illite, kaolinite, montmorillonite, boehmite, smectite (smectite), vermiculite, talc, and silica; dispersing agents, etc., and these may contain 1 or 2 or more species.

The content of other additives than the above-mentioned essential components which can be used in the present invention is not particularly limited as long as the preferable physical properties of the present invention are not impaired. In general, the total amount of the resin composition is preferably 10% by mass or less, more preferably 5% by mass or less, based on 100% by mass of the total amount of the resin composition.

(method for producing resin composition)

The resin composition can be produced by mixing and heating (particularly, melt-kneading) the polyamide resin, the fibrous reinforcing material, the polyamide-based elastomer, the non-fibrous titanic acid compound particles as needed, and other additive components.

In the melt kneading, a known melt kneading apparatus such as a twin-screw extruder can be used. Specifically, the present invention can be produced by the following method: (1) a method in which the respective components are premixed by a mixer (a tumbler, a henschel mixer, or the like), melt-kneaded by a melt-kneading apparatus, and pelletized by a pelletizing mechanism (a pelletizer or the like); (2) a method of preparing a master batch of a desired component, mixing other components as needed, and melt-kneading the mixture by a melt-kneading apparatus to form pellets; (3) a method of supplying each component to a melt kneading apparatus and pelletizing the component.

The processing temperature in the melt kneading is not particularly limited as long as it is a temperature at which the polyamide resin can be melted. The cylinder temperature of the melt-kneading apparatus for melt-kneading is usually adjusted to this range. Thus, the resin composition used in the present invention can be produced to exhibit the desired effects.

Sliding element and use

The sliding member of the present invention can be produced by shaping the resin composition by a known resin molding method such as injection molding, insert molding, compression molding, blow molding, or inflation molding, depending on the type, application, shape, and the like of the target member. In addition, a molding method combining the above molding methods can be employed.

The sliding member of the present invention can be suitably used for a sliding member which is required to have a high friction coefficient without performing surface treatment (plating, metal coating, or the like) on the sliding surface, and can be suitably used as a thrust member (bush, friction member) of a torque fluctuation absorbing device having a hysteresis generating mechanism, for example. The thrust member is preferably an annular member.

The torque fluctuation absorbing device is disposed in a power transmission path between a power source such as an engine or an electric motor and a transmission, and the torque fluctuation absorbing device includes: a first rotating member; a second rotating member disposed coaxially with the first rotating member; a control plate that is disposed between the first rotating member and the second rotating member in the axial direction and that is engaged with the second rotating member so as to be non-rotatable; a thrust member that is disposed between the first rotating member and the control plate in an axial direction, engages with the first rotating member so as to be non-rotatable but axially movable, and slidably contacts with the control plate; and an elastic member that is disposed between the first rotating member and the thrust member in the axial direction, is supported by the first rotating member, and presses the thrust member against the control plate.

The sliding surfaces of the thrust member and the control plate may be formed in a predetermined shape so that, when the thrust member and the control plate are twisted, the thrust member is displaced in the axial direction with respect to the control plate to change the pressing load of the elastic member, thereby changing the hysteresis value generated between the thrust member and the control plate.

The sliding member of the present invention can be suitably used for: an annular member, that is, a thrust member (thrust washer, thrust bearing) or the like, which is used to slidably contact an annular target member such as a control plate in the torque fluctuation absorbing device as described above.