JP2912034B2 - Multi-layer sliding member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer sliding member provided with a lubricating composition mainly composed of polytetrafluoroethylene (hereinafter referred to as "PTFE") resin on a sliding surface.

[0002]

2. Description of the Related Art Conventionally, PTFE resins have been widely used as sliding members such as bearings because of their excellent self-lubricating properties, low coefficient of friction, and excellent chemical and heat resistance. .

However, on the other hand, sliding members made of only PTFE resin are inferior in abrasion resistance and creep resistance. Therefore, depending on the use of the sliding member, for example, (1) graphite, molybdenum disulfide, glass fiber, etc. Blending fillers,
(2) The above disadvantage is solved by impregnating and coating a porous sintered alloy layer integrally formed on a thin steel plate. the above
As the sliding member having the mode (2), for example,
A sliding member disclosed in, for example, Japanese Patent Application Laid-Open No. 22486 and Japanese Patent Application Laid-Open No. 2-107818 has been proposed.

[0004]

The sliding members of the prior art described above exhibited sliding characteristics such as excellent friction characteristics and abrasion resistance. However, the sliding members are used for applications (for example, OA equipment). In some cases, conductivity is required. However, there has been a new problem that the sliding member of the prior art cannot sufficiently meet these requirements. In general, as a method for imparting conductivity to a synthetic resin, a conductive material such as carbon fiber or carbon black is added. When these materials are added to a PTFE resin, the conductivity is improved, but the sliding characteristics are reduced. In particular, when carbon fibers are added, there is a problem that the mating shaft is damaged.

An object of the present invention is to provide a multilayer sliding member exhibiting excellent sliding characteristics and also having conductivity.

[0006]

In order to solve the above-mentioned problems, the present invention provides the following technical means.
That is, according to the present invention, the porous sintered metal layer formed on the steel back metal contains PTFE resin as a main component and 5 to 30% by weight of carbon fiber and 0.1 to 15% by weight of phosphate as a filler. An object of the present invention is to provide a multilayer sliding member characterized in that these are further impregnated and coated with a lubricating composition containing 0.1 to 10% by weight of a conductive substance.

In the above-described construction, the back metal is made of a metal sheet, and a rolled steel sheet for a structure is generally used. However, depending on the use of the sliding member, another steel sheet or a metal sheet other than steel may be used. The metal thin plate may be plated with copper or the like to improve corrosion resistance. The porous sintered metal layer integrally formed on the back metal is formed of a copper alloy having excellent friction and wear properties such as bronze, lead bronze, and phosphor bronze. It may be formed from an aluminum alloy, iron, or the like. The particle form of these alloy powders is preferably a lump or irregular.

Examples of the PTFE resin as a main component of the lubricating composition include fine powders (for example, “Teflon 6CJ (trade name)” manufactured by DuPont Mitsui Fluorochemicals, “Polyflon F201 (trade name)” manufactured by Daikin Industries, "Fluon CD-076, CD-126, CD" manufactured by Asahi Glass Co., Ltd.
-4 (product name) ”).

In the present invention, as a filler for the PTFE resin, carbon fibers, phosphates, and, in some cases, a powder of a conductive substance are used. Carbon fiber (hereinafter, referred to as “CF”) plays a role as a substance for imparting conductivity to the lubricating composition and a role to compensate for a defect of the PTFE resin inferior in wear resistance and creep resistance. As a CF, pitch system treated at low temperature (about 1000 to 1500 ° C), PAN
(Polyacrylonitrile) -based and phenol-based CF and pitch-based, PAN-based and phenol-based CF treated at high temperature (about 2000 to 2500 ° C.) are used.
From the viewpoint of imparting high conductivity to the lubricating composition, the latter C
F, from the viewpoint of compensating wear resistance and creep resistance, the former C
It is preferred to use F. Specific examples of pitch-based CF include “Zyrath (trade name)” manufactured by Nitto Boseki Co., Ltd., and PAN.
As a specific example of the carbon fiber, "Pyrofil (trade name)" manufactured by Mitsubishi Rayon Co., Ltd., and as a specific example of the phenolic CF, "Kynol CF16BT" manufactured by Nihon Kainol Co., Ltd.
(Product name) ". Regarding the size of the CF, that is, the diameter and the length, the diameter is preferably 1 to 20 μm and the length is preferably 30 to 3 mm. In consideration of the problem in the production of the lubricating composition, the diameter is about 10 μm and the length is 100 μm. The one before and after is preferred. And the compounding ratio of CF with respect to the lubricating composition is 5 to 30% by weight.
When the content is less than 5% by weight, it is difficult to impart conductivity to the lubricating composition, and when the content exceeds 30% by weight, further improvement in conductivity cannot be expected. Instead, it degrades the wear characteristics.

[0010] Phosphate itself is not a lubricating substance such as, for example, graphite or molybdenum disulfide.
When blended with the FE resin, it has an effect of promoting the film forming property of the lubricating coating of the PTFE resin on the surface (sliding surface) of the partner material in sliding with the partner material. The effect of the phosphate prevents direct contact (sliding) between the hard CF compounded in the PTFE resin and the mating material, damaging the mating material of the CF and reducing the wear resistance of the sliding member. This is an important requirement required for sliding members used under dry friction lubrication. As the phosphate used in the present invention, tertiary phosphate, secondary phosphate,
Metal salts such as pyrophosphoric acid, phosphorous acid, and metaphosphoric acid, and mixtures thereof. Among them, tertiary phosphate, secondary phosphate and pyrophosphate are preferred. As the metal, an alkali metal, an alkaline earth metal and a transition metal are used. Among them, an alkali metal and an alkaline earth metal are preferable, and lithium, calcium, magnesium and barium are particularly preferable. Specifically, lithium phosphate, lithium hydrogen phosphate, lithium pyrophosphate,
Tricalcium phosphate, calcium pyrophosphate and calcium hydrogen phosphate are most preferred. Also, hydroxyapatite can be preferably used. This phosphate is uniformly mixed with the above-mentioned PTFE resin and CF, and preferably has an average particle size of 20 μm or less. Phosphate starts to show the effect of promoting the film-forming property of the lubricating film in a small proportion of the lubricating composition, for example, in a proportion of 0.1% by weight, and forms a film to 15% by weight. The sexual effect is maintained. But,
If the amount exceeds 15% by weight, the amount of the lubricating film formed on the surface of the mating member becomes too large, and the wear resistance is rather lowered. Therefore, the mixing ratio of the phosphate is preferably 0.1 to 15% by weight, more preferably 3 to 10% by weight.

A certain percentage of powder of a conductive substance can be blended with the lubricating composition comprising the above-mentioned PTFE resin, CF and phosphate without further lowering the friction and wear characteristics. By blending, a higher conductivity can be imparted to the lubricating composition. As the conductive substance used in the present invention, coke, anthracite,
Examples include amorphous carbon powder such as carbon black and charcoal, graphitic carbon powder such as natural graphite, artificial graphite and quiche graphite, copper powder, nickel powder, and soft metal powder such as lead, tin and indium. Since most of these conductive substances do not contribute to the improvement of the friction and wear characteristics, attention should be paid especially to the mixing ratio. In the present invention, 0.1 to 0.1
It was confirmed that within the range of 10% by weight, the lubricating composition could be provided with higher conductivity without lowering the friction and wear characteristics.

Next, a method of manufacturing the sliding member will be described. (Preparation of lubricating composition) 5 to 3 parts of PTFE resin powder
0% by weight of CF and 0.1-10% by weight of phosphate,
In some cases, 0.1 to 10% by weight of a conductive substance powder is mixed while being pulverized at a temperature lower than the room temperature transition point (19 ° C.) of the PTFE resin, and the lubricating composition is maintained while maintaining the mixture at a temperature lower than 19 ° C. Petroleum solvent 1
5-20 parts by weight are added and mixed with stirring to obtain a wet lubricating composition. Here, naphtha, toluene,
Xylene, aliphatic solvents, aliphatic and naphthenic mixed solvents are used. If the blending ratio of the petroleum solvent to the lubricating composition is 15 parts by weight or less, the spreadability of the lubricating composition in the impregnating coating step on the porous sintered metal layer described below is poor, and the impregnating coating on the sintered layer may be uneven. It is easy to occur. If the amount exceeds 25 parts by weight, not only does the impregnation coating work become difficult, but also the uniformity of the coating thickness is impaired, and the adhesion strength between the lubricating composition and the sintered layer is deteriorated. This mixture is PTFE
By carrying out at a temperature below the room temperature transition point of the resin,
Fiberization of the TFE resin is prevented, and a uniform mixture can be obtained.

(Manufacture of sliding member) (a) A lubricating composition provided with wettability is sprayed and supplied onto a porous sintered metal layer formed on a backing metal, and rolled by a roller to form a sintered layer. The lubricating composition is impregnated and a uniform coating layer of the lubricating composition is formed on the surface of the sintered layer. In this step, the lubricating composition is coated to a thickness of 2 to 2.5 times the resin coating thickness required for the final product. Most of the filling of the resin into the voids of the porous sintered metal layer proceeds in this step. (B) Next, the back metal, in which the porous sintered metal layer is impregnated with the lubricating composition, is kept in a drying furnace heated to a temperature of 200 to 250 ° C. for several minutes to dissipate the petroleum-based solvent. Removed, and then the dried lubricating composition layer is roughly 300 to 600 kg /
It is pressurized by a pressure of cm ² . (C) Next, the back metal provided with the dry lubricating composition layer pressed by a roller is introduced into a heating furnace, heated at a temperature of 360 to 380 ° C. for several minutes to several tens of minutes, and baked. Take it out of the furnace and pass it through the rollers again to adjust the dimensional variation. (D) After adjusting the dimensions, the back metal on which the sliding surface layer is formed is cooled, and then, if necessary, passed through a straightening roller for correcting undulations of the back metal to obtain a desired multilayer sliding member. After the multilayer sliding member is cut into an appropriate size, it can be used as a slide plate in a flat state, or can be round-bent and used as a cylindrical wound bush.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. [Example 1] PTFE resin powder having an average particle size of 80 µm
The following “Teflon 6C” of Mitsui DuPont Fluorochemicals
J ”and add 12 μm in diameter to this PTFE resin powder.
m, CF with a length of 100 μm (Zyras G
PMF100JL ") 5 to 30% by weight and 5% by weight of calcium pyrophosphate (manufactured by Kanto Chemical Co., Ltd.) passing through a 350 mesh as a phosphate are charged into a Henschel mixer and pulverized and mixed. As a petroleum-based solvent, 20 parts by weight of an aliphatic / naphthene-based mixed solvent (“EXSOL” of Exxon Chemical Co., Ltd.) was blended, and the PT
The wet lubricating composition was obtained by mixing at a temperature below the room temperature transition point of the FE resin. The wet lubricating composition is supplied onto a porous sintered metal layer formed on a steel backing made of a thin metal plate, and is rolled by a roller to coat so as to have a thickness of 1.20 mm to form a multilayer plate. After holding the multilayer plate in a hot-air drying furnace heated to a temperature of 200 ° C. for 5 minutes to remove the solvent by scattering, the dried lubricating composition layer was pressed by a roller at a pressing force of 400 kg / cm ² to obtain a thickness. 1.05 mm. Next, the pressed multi-layer plate is introduced into a heating furnace and baked for 10 minutes at a temperature of 370 ° C., and then pressurized again by a roller to adjust the dimensions and correct the undulation of the plate. Cut, side 30m
A plate-like sliding member test piece of mx 30 mm x thickness 1.05 mm was obtained. Table 1 shows the component composition of the lubricating composition constituting the sliding member according to [Example 1].

Example 2 As a PTFE resin powder, "Teflon 6CJ" manufactured by DuPont-Mitsui Fluorochemicals Co., Ltd. having an average particle diameter of 80 μm or less was used, and 15% by weight of CF having a diameter of 12 μm and a length of 100 μm was added to this PTFE resin powder. 3 to 10% by weight of lithium pyrophosphate (Yoneyama Chemical Industry Co., Ltd.) passing through a 350 mesh as an acid salt is charged into a Henschel mixer, pulverized and mixed.
20 parts by weight of a petroleum-based solvent of an aliphatic / naphthene-based mixed solvent (“EXSOL” manufactured by Exxon Chemical Co., Ltd.) and mixed at a temperature lower than the room temperature transition point of the PTFE resin. I got something. Hereinafter, the manufacturing process was performed in the same manner as in [Example 1], and the side was 30 mm × 30 mm.
A plate-like sliding member test piece having a size of 1.0 mm × 1.05 mm was obtained.
Table 1 shows the component composition of the lubricating composition constituting the sliding member made of [Example 2].

[Example 3] Teflon 6CJ of Mitsui DuPont Fluorochemicals having an average particle size of 80 µm or less was used as PTFE resin powder, and 5 to 20% by weight of CF having a diameter of 12 µm and a length of 100 µm was added to the PTFE resin powder. 5% by weight of calcium pyrophosphate (manufactured by Kanto Kagaku) passing through 350 mesh as a phosphate and carbon black (manufactured by Mitsubishi Kasei Kogyo KK: CB3)
750, hereinafter referred to as “CB”. ) 2% by weight was put into a Henschel mixer and pulverized and mixed, and 100 parts by weight of the mixed powder was mixed with 20 parts by weight of an aliphatic / naphthene-based mixed solvent ("EXSOL" of Exxon Chemical Company) as a petroleum-based solvent. Then, the PTFE resin was mixed at a temperature lower than the room temperature transition point to obtain a wet lubricating composition. Hereinafter, the manufacturing process is performed in the same manner as in [Example 1], and the side is 30 mm × 30 mm ×
A plate-shaped sliding member test piece having a thickness of 1.05 mm was obtained. Table 1 shows the component composition of the lubricating composition constituting the sliding member made of [Example 3].

[Comparative Example] As the PTFE resin powder, “Teflon 6CJ” manufactured by Mitsui DuPont Fluorochemicals Co., Ltd. having an average particle size of 80 μm or less was used.
(1) 30% by weight of CF having a diameter of 12 μm and a length of 100 μm; (2) 40% by weight of CF having a diameter of 12 μm and a length of 100 μm; and 5% by weight of calcium pyrophosphate.
2 μm, 40% by weight of CF having a length of 100 μm, 5% by weight of calcium pyrophosphate and 2% by weight of CB as a conductive substance, (4) 15% by weight of CF having a diameter of 12 μm and 100 μm in length and 2% by weight of CB as a conductive substance in a Henschel mixer And pulverized and mixed, and the mixed powder 100
A wet lubricating composition is prepared by mixing 20 parts by weight of an aliphatic / naphthene-based mixed solvent (“EXSOL” of Exxon Chemical Co., Ltd.) as a petroleum-based solvent with respect to parts by weight and mixing at a temperature below the room temperature transition point of the PTFE resin. I got Hereinafter, the manufacturing process is performed in the same manner as in [Example 1], and the side is 30 mm × 30 m.
A plate-shaped sliding member test piece of mx 1.05 mm in thickness was obtained. Table 1 shows the component composition of the lubricating composition constituting the sliding member made of this [Comparative Example].

Next, the friction and wear characteristics and the volume resistivity (Ω · cm) of the sliding members obtained in the above Examples and Comparative Examples are described.
The results of the tests for are described below. [Friction and wear characteristics] The friction and wear characteristics were measured under the following sliding conditions. (Sliding conditions) Sliding speed 11 m / min Load 100 kgf / cm ² Test time 8 hours Lubrication Unlubricated partner Material Carbon steel for machine structure (S45C) The friction coefficient indicates the fluctuation value of the friction coefficient 1 hour after the start of the test. As for the amount of wear, the amount of wear after 8 hours of the test time was measured. [Volume resistivity] The volume resistivity in the direction perpendicular to the surface of each sliding member was measured by a four-probe resistivity measurement method using a resistivity meter (Lolster APMcp) manufactured by Mitsubishi Yuka Co., Ltd.
-T400). Table 1 shows the friction and wear characteristics and the volume resistivity of each sliding member.

[0019]

[Table 1]

From the test results, it was found that the sliding members of Examples 1 to 3 exhibited stable performance with a low coefficient of friction throughout the test time, and the amount of wear of the sliding members after the test was extremely small. The sliding member of Example 1-6 is CF
Despite containing 30% by weight, no damage was observed on the surface of the mating material after the test. The volume resistivity showed a value of 10 ⁸ to 10 ⁻¹ . Generally, the conductivity required for the sliding portion of the OA equipment is a satisfactory performance considering that the volume resistivity is 10 ⁸ or less.

On the other hand, the sliding member according to the comparative example is a very excellent material from the viewpoint of conductivity, but has a high coefficient of friction and a large amount of wear in terms of friction and wear characteristics. Numerous fine streak-like injuries were observed.

[0022]

The present invention has the above-mentioned structure,
It has the following unique effects. (1) The lubricating composition impregnated and coated on the porous sintered metal layer formed on the back metal exerts stable performance with a low friction coefficient without damaging the mating material in sliding with the mating material. . (2) Since the lubricating composition impregnated and coated on the porous sintered metal layer formed on the back metal has conductivity, it can be used for sliding parts of various OA equipments that require an antistatic effect, The range of use is greatly expanded.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16C 33/18 F16C 33/18 33/20 33/20 Z // C10N 10:02 10:04 10:16 20:06 30: 06 40:02 (58) Field surveyed (Int.Cl. ⁶ , DB name) C10M 169/04 C10M 107/38 C10M 125/02 C10M 125/24 C10N 40:02

Claims (5)

(57) [Claims] 1. A porous sintered metal layer formed on a steel backing metal containing polytetrafluoroethylene resin as a main component, 5 to 30% by weight of carbon fiber and 0.1 to 15% by weight of phosphate as a filler. %, Which is impregnated with a lubricating composition containing 0.1% by weight. 2. The lubricating composition further comprises a conductive substance of 0.1 to
The multilayer sliding member according to claim 1, which contains 10% by weight. 3. The conductive substance is one of amorphous carbon powder, graphitic carbon powder, copper powder, nickel powder and soft metal powder.
3. The multi-layer sliding member according to claim 2, wherein the member is selected from a kind or two or more kinds. 4. The phosphate is a tertiary phosphoric acid, a secondary phosphoric acid,
The multilayer sliding member according to any one of claims 1 to 3, wherein the sliding member is a metal salt selected from one or more of pyrophosphoric acid, phosphorous acid, and metaphosphoric acid. 5. The phosphate is selected from one or more of lithium phosphate, lithium hydrogen phosphate, lithium pyrophosphate, tricalcium phosphate, calcium pyrophosphate, calcium hydrogenphosphate and hydroxyapatite. Item 5. The multilayer sliding member according to any one of Items 1 to 4.