JPH026125A - Double-layer sliding member and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a double-layer sliding member displaying a friction coefficient stable over a long term and having excellent abrasion resistance by impregnating and coating a porous sintered metallic layer formed onto a steel back plate with a specific resin composition composed of an addition polymerization type PI resin, graphite and PTFE. CONSTITUTION:A porous sintered metallic layer integrally shaped onto a back plate is formed of a copper alloy having frictional wear characteristics such as bronze, lead bronze, phosphor bronze, etc. Loading to PTFE of PI resin powder is brought to 5-40wt.%, preferably 15-25wt.%. A satisfactory result is acquired by the loading of 0.1-10wt.%, preferably 0.5-5wt.% to PTFE and a PI resin in graphite (Gr) compounded with PTFE and the PI resin. The back plate, in which the porous sintered metallic layer is impregnated and coated with a resin composition 5 containing a petroleum solvent, is heated at a temperature of 200-250 deg.C and the petroleum solvent is scatterred and removed, and the back plate is pressed to specified thickness by a roller 8. The whole back plate with a resin coated layer pressed by the roller is introduced into a heating furnace 9, and backed gradually at a temperature of 360-380 deg.C and extracted, and pressed by a roller 10 again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multi-layered sliding member and a method for manufacturing the same.

[Prior art]

Conventionally, a steel backing metal with a porous sintered metal layer is made of polytetrafluoroethylene resin (hereinafter referred to as PTFE J) or PTFE as the main component, and various fillers such as lead, lead oxide, metal sulfide, and glass fiber are added to the steel backing metal. Many multilayer sliding members impregnated with PTFE compositions containing organic fillers such as tetrafluoroethylene and hexafluoropropylene resins have been proposed, and the present applicant has Also proposed Japanese Patent Application No. 144440/1982 (-Japanese Patent Application No. 37415/1982) and Japanese Patent Application No. 138582/1982.

The above-mentioned patent application No. 144440/1982, Japanese Patent Application No. 138/1982
The technology of No. 582 is PTF! l! This is a multilayer sliding member in which a porous sintered metal layer of a steel backing is impregnated with a PTFE composition containing a certain proportion of polyimide resin (hereinafter referred to as rPI resin). The sliding member had excellent friction and wear characteristics and could be used without lubrication in a high-temperature atmosphere.

[Problem that the invention seeks to solve]

However, even with multi-layer sliding members that exhibit the above-mentioned performance, their durability may vary depending on the usage conditions.For a certain period of time after startup, they exhibit excellent friction and wear characteristics such as a low coefficient of friction and extremely small amount of wear. However, after this period has elapsed, the coefficient of friction changes and the amount of wear increases.

The present inventors pursued to solve this problem, and as a result, the above-mentioned problem was solved by P
It was considered that this was related to the particle size of the I resin. When we observed the sliding surface of the multi-layer sliding member that had problems with durability, we found that quite a large amount of PI resin was exposed on the sliding surface, and after a certain period of time, friction with this PI resin started to occur. It was assumed that this was due to the Therefore, when the particle size distribution of the PI resin powder used was investigated, it was confirmed that the particle size was distributed over a fairly wide range from a maximum of 100 μm to a minimum of 1 μm.

Since this PI resin is not compatible with PTFH in which it is blended, it exists dispersedly in PTFEi, which is the main component. It was concluded that it had a significant impact on

The particle size distribution of this PI resin should be kept within a small range, e.g.
By using particles in the range of 0 to 40 μm, the above-mentioned problems are solved, but if the particle size distribution is up to 100 μm
In order to reduce the minimum value of 1 .mu.I from the range of 1 .mu.I to 30 to 40 .mu.I, it not only takes time and effort, but also is not a good idea from the viewpoint of material yield.

In view of the above points, the present inventors have conducted intensive research and found that PTF
Graphite (Gr
) is impregnated into a porous sintered metal layer of a steel backing to form a multilayer sliding member, which not only can solve the above-mentioned problems at once, but also has excellent moldability. It was discovered that this method also produces the secondary effect of improving machinability, and based on this knowledge, the present invention was developed.

The present invention aims to obtain a multilayer sliding member that always shows a stable coefficient of friction over a long period of time and has excellent wear resistance even when using PI resin powder with a wide particle size distribution and non-uniform particle size. This is the purpose.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention adopts the following technical means, that is, the configuration.

That is, a resin composition consisting of 5 to 40% by weight of addition polymerizable PI resin, 0.1 to 10% by weight of graphite, and the remainder PTFE is impregnated and adhered to a porous sintered metal layer formed on a steel backing. A multilayer sliding member and a manufacturing method thereof.

In the above structure, the back metal is made of a thin metal plate, and generally a structural rolled steel plate is used, but depending on the purpose of the sliding member, it may be another thin steel plate or a metal thin plate other than steel plate, and these thin metal plates may be coated with copper. It may be plated or the like to improve corrosion resistance.

The porous sintered metal layer integrally formed on the backing metal is made of a copper alloy with excellent friction and wear properties such as bronze, lead bronze, or phosphor bronze. It can also be formed from aluminum alloy, iron, etc.

The particle form of these alloy powders is preferably blocky or irregularly shaped.

As the PTFE that forms the main component of the resin composition, PTFE
Fine powder (for example, "Teflon 6CJ (trade name)" manufactured by Mitsui DuPont Fluorochemical Co., Ltd., "Polyflon F201 (trade name)" manufactured by Taikin Industries, Ltd., "Fluon CD-076, CD-126, CD-" manufactured by Asahi Glass Co., Ltd.) 4
(Product name)” is used.

As the addition polymerization type PI resin to be blended with PTFH, which is the main component, polyamino bismaleimide, which is commercially available as a raw resin for molding compounds under the trade name "Kelimide" from Loos-Boulin, is exemplified as a preferable one. Ru. This polyamino bismaleimide resin is a thermosetting polyimide resin produced by addition polymerization of maleic anhydride and diaminodiphenylmethane, and this PI resin powder has a particle size distribution in a wide range of 1 μm to 100 μm.

The blending amount of this PI resin powder in PTFIE is 5 to 4
It is 0% by weight, preferably 15-25% by weight. If it is less than 5% by weight, no effect on improving wear resistance can be obtained;
When blended in excess of 1% by weight, the properties of PI resin will appear strongly,
This is not preferable because it not only impairs the low friction properties of PTFH, which is the main component, but also reduces wear resistance.

Graphite (Gr), which is blended with the above-mentioned PTFE and PI resin, compensates for fluctuations in the friction coefficient of sliding members and decreases in wear resistance caused by the wide particle size distribution and non-uniform particle size of the PI resin powder. Therefore, it is required to be contained in a uniformly dispersed manner.

In the present invention, good results were obtained using particles with an average particle diameter of 5 μm or less. For example, the product name rJACPJ manufactured by Nippon Graphite Industries Co., Ltd.
, rC3SPJ, etc. are exemplified as preferred.

Since the blending of Gr will actually impair the low friction properties inherent to PTFE, particular care must be taken regarding the blending amount.

In the present invention, good results were obtained with a blending amount of 0.1 to 10% by weight, preferably 0.5 to 5% by weight, based on the PTFE and PI resin.

If it is less than 0.1% by weight, no blending effect can be obtained;
If the amount is exceeded, the low friction property inherent to PTFE described above will be impaired and the coefficient of friction will increase.

The effect of the blending of Gr is to compensate for the drawbacks of the above-mentioned PI resin and improve the friction and wear characteristics. It has the secondary effect of improving machinability when forming bush bearings. That is,
When two or more multi-layer bush bearings of the present invention are embedded in reinforced plastic to form a single structural part and used in combination with a mating shaft, the distance between the centers of the bush holes, the parallelism, etc. Reaming is performed to adjust the deviation, and the addition of Gr improves the roundness after reaming and makes the sliding surface smoother. Furthermore, when chamfering the end face of the wound bushing bearing, the cutting dust in the resin layer turns into fine cutting dust, so the cutting dust does not get entangled with the cutting tool, and cutting workability (workability) is improved.

The petroleum solvent added to the resin composition consisting of PTFE, PI resin, and Gr is blended in an amount of 18 to 25 parts by weight based on 100 parts by weight of the resin composition.

If the amount of the petroleum solvent is small, the spreadability of the composition during the manufacturing process will be poor, and the impregnating adhesion of the resin composition to the porous sintered metal layer will likely be uneven. Furthermore, if too much petroleum-based solvent is used, not only will it be difficult to perform the adhesion process, but the uniformity of the adhesion film formed on the porous sintered metal layer will be impaired, and the adhesion strength will be poor.

Petroleum-based solvents include naphtha, toluene, xylene, aliphatic solvents, and aliphatic/naphthenic mixed solvents.
Examples of commercially available products include Isopar (manufactured by Exxon Chemical Co., Ltd.).

Next, the manufacturing method will be explained.

PTFE powder, PI resin powder, and Gr lead powder PTFE having the above composition are mixed while being crushed at a temperature below the room temperature transition point (19°C), and a petroleum solvent is added while maintaining the mixture at a temperature below 19°C. A coating composition is prepared by stirring and mixing.

One of the factors for imparting sufficient strength and bearing properties to the resin composition layer impregnated onto the porous sintered metal layer is the preparation of a uniform resin composition. This is because kneading is added to FTPH during pulverization and mixing and stirring, resulting in PTP.
This is to prevent the progress of fiberization of the E particles, which significantly reduces the moldability of the wet resin mixture and prevents it from functioning as an adherent resin.

To obtain a multilayer sliding member in which a resin adhesion layer is formed by impregnating and adhering a porous sintered metal layer formed on a backing metal, first, a petroleum-based solvent supplied to the porous sintered metal layer is Contains PTFE
, A resin composition consisting of PI and Gr is rolled with a roller to impregnate and adhere to the porous sintered metal layer.

Next, the porous sintered metal layer is impregnated with a resin composition containing a petroleum-based solvent, and the back metal is heated to a temperature of 200 to 250°C and maintained at this temperature for several minutes to remove the petroleum-based solvent. After removing the scattered particles, it is pressed with a roller to a predetermined thickness. The pressing force at this time is approximately 300 to 600
kg/cri.

Next, the entire backing metal with the resin adhesion layer pressed by a roller is introduced into a heating furnace and heated at a temperature of 360 to 380°C for several minutes to more than 10 minutes to proceed with baking, and then taken out. Pressure is applied again using the roller.

This roller pressure is for adjusting dimensional variations in the range of 10-3 to 10-'' mm.

After adjusting the dimensions, the backing metal with the resin layer adhered thereto is cooled, and then passed through a straightening roller to correct the waviness of the backing metal, if necessary, to form a desired multilayer board.

After cutting this multilayer board into an appropriate size, it can be used in the flat state as a sliding board, or it can be rounded and used as a cylindrical wound bush.

The figure is an explanatory diagram showing the manufacturing method of the present invention.

In the figure, 1 is a hoop material in which a steel backing 2 made of a thin steel plate integrally provided with a porous sintered metal layer is wound into a coil shape; 3.
3 is a guide roller, 4 is a hopper, and 5 is a wet resin composition.

6.6 is a pressure roller that rolls and deposits the composition 5 supplied on the porous sintered metal layer of the steel backing 2 to a thickness of -.In this process, the composition is necessary for the final product. The resin is deposited to a thickness that is 2 to 2.5 times the resin deposition thickness. Most of the impregnation of the resin into the voids of the porous sintered metal layer proceeds during this step.

7 is a hot air drying oven where the ambient temperature is adjusted to approximately 200 to 250°C. When the steel back metal with the resin coating layer is passed through this hot air drying oven, most of the volatile components in the resin composition are removed.

8. Press the dried resin adhesion layer onto the porous sintered metal layer of the steel backing metal 2 to a thickness required for the final product using a sizing and pressing row. In this step, the resin is impregnated into the voids as described above, and the porous sintered metal layer is completely impregnated into the voids.

9 is a heating furnace for firing the resin, approximately 360-380℃
The ambient temperature is adjusted to . The steel back metal with the resin coating layer treated with the pressure roller 8.8 passes through the furnace for several to ten-odd minutes, and the firing and hardening of the resin composition is completed.

10.10 is a size adjustment roller, which is 10-3 to 10 of the thickness of the resin layer impregnated and adhered to the porous sintered metal layer of the steel backing metal 2.
Fine dimensional adjustments in the range of "" m are performed with this roller when it is hot. The temperature is controlled by passing a coolant inside this roller.

11 is a cooling device that uses cold water spray, etc. In this device, f
Cool the back metal to about room temperature.

Reference numeral 12 denotes a correction roller, and this correction roller 12 corrects slight waviness of the steel back metal.

13.13 is a guide roller, 14 is a coiler, and the multilayer board that has passed through the guide roller 13.13 is wound up by the coiler 14.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

<Example> PTFt! Powder (trade name: 6CJ, manufactured by DuPont Mitsui Fluorochemical Co., Ltd.) contains PI powder (trade name: Kelimide l110) with a particle size distribution of 1 to 100 μm and an average particle size of 40 μm.
00, manufactured by Rhone-Poulenc) and Gr powder (trade name:
CSSP (manufactured by Nippon Graphite Co., Ltd.) was blended in the composition ratio shown in the table below, pulverized and mixed uniformly using a Henschel mixer, and Isopar (manufactured by Exxon Chemical Co., Ltd.) was added to the mixed powder to prepare a coating composition.

The coating resin composition is supplied onto a porous sintered metal layer formed on a steel backing made of a thin metal plate, and rolled with a roller to coat the layer to a thickness of 1.2 On to form a multilayer plate. After holding the multilayer board in a hot air drying oven heated to a temperature of 200° C. for 5 minutes to scatter and remove the solvent, the resin adhesion layer was pressed with a roller at a pressure of 400 kg/clT+2 to a thickness of 1
．． 05mm.

Next, the pressurized multilayer plate is introduced into a heating furnace and 37
After heating and baking at a temperature of 0° C. for 10 minutes, pressure was applied again with a roller to adjust the dimensions and correct the waviness of the plate.

The multilayer board thus obtained was cut into strips and wound with the resin adhesion layer inside to give an outer diameter of 12 mm and an inner diameter of 10 mm.
A cylindrical sliding member with a length of 10 mm was obtained. This cylindrical sliding member was used as a test piece and tested for friction and wear characteristics under the following test conditions. The results are shown in the table below.

(Test conditions) Speed: 30m/win Load: 1 kg/co
? Time: 30Hr Lubrication: Dry lubrication (dry) Mating shaft: 5tlS303, mating material surface roughness 0.8
S test: Journal test Comparative example> (Comparative example: 1) 20% of the above PI resin powder was blended with the above PTFE powder, and a multilayer sliding member was obtained in the same manner as in the above example. This multi-layer sliding member was cut into strips and wound with the resin adhesion layer inside to give an outer diameter of 12 mm, an inner diameter of 10 mm, and a length of 110 mm.
A cylindrical sliding member of ff1 was obtained. This cylindrical sliding member was used as a test piece, and its friction and wear characteristics were tested using the above test method. The results are shown in the table below.

(Comparative Example: 2) 20% by weight of the above PI resin powder and 15% by weight of the Gr powder were blended with the above PTFIE powder, and a multilayer sliding member was obtained in the same manner as in the above example. This multi-layer sliding member was cut into strips and wound with the resin adhesion layer inside.
A cylindrical sliding member with a 111% inner diameter of 10 mm+ and a length of 10 mm was obtained. This cylindrical sliding member was used as a test piece, and its friction and wear characteristics were tested using the above test method. The results are shown in the table below.

As is clear from the above test results, the sliding member of the present invention exhibited a stable coefficient of friction throughout the test period, and the amount of wear was extremely small.

This is PI in which Gr is dispersed in PTFE and Gr is blended at a ratio of 0.1 to 10% by weight with respect to PTFE and P resin.
It is presumed that the abrasion resistance of the sliding member is improved by being present around the resin and preventing direct sliding contact between the mating material and the PI resin.

In addition, in the above Example 1 and Comparative Example 2, the rotation speed was 70 Qrp.
When the roundness and roughness were measured after reaming with a diameter of 8.5 μm, Example 1 had a roundness of 8.5 μm and a roughness of 4.5 μm.
The roundness of Comparative Example 2 was 1 μm, whereas the roundness was 28.
The roughness was 9.8 μm.

〔effect〕

The multilayer sliding member of the present invention has the following unique effects.

■ A resin composition made by adding and mixing graphite to a resin mixture consisting of tetrafluoroethylene resin and addition polymerized polyimide resin was coated on a back metal having a porous sintered metal layer to make a multilayer sliding member. Therefore, under low load and high speed conditions,
Even when polyimide resin powder with a wide particle size distribution and uneven particle size is used, it always exhibits a stable coefficient of friction, excellent wear resistance, and excellent machinability.

■Tetrafluoroethylene resin powder, addition polymerized polyimide resin powder, and graphite powder are pulverized and mixed at a temperature below the room temperature transition point of the tetrafluoroethylene resin, so the tetrafluoroethylene resin is stretched by shearing force. The two resins are pulverized and mixed uniformly. As a result, the degree of impregnation of the resin into the voids of the porous sintered metal layer is improved, and in addition to the mechanical bonding of the resin composition to the backing metal, the adhesive curing by the polyimide resin is also added, resulting in high adhesion strength and the adhesion of the adhered resin film. It has the advantage of being sufficiently strengthened.

■When adding a petroleum solvent to a tetrafluoroethylene resin and an addition-polymerized polyimide resin composition and wetting the resin composition by stirring and mixing, the process is carried out at a temperature below the room temperature transition point of the tetrafluoroethylene resin. Therefore, the advantage is that it is possible to completely prevent a phenomenon in which shearing force acts on the tetrafluoroethylene resin, causing fiberization of the tetrafluoroethylene resin particles and inhibiting the moldability of the resin composition. has.

Both the pulverization and mixing of the two resins and the stirring and mixing of the pulverized and mixed resin composition and the solvent need only be controlled below the room temperature transition point of the tetrafluoroethylene resin, and the temperature range to be controlled in the process is sufficiently wide. It has the advantage of being easy to set and temperature control.

[Brief explanation of the drawing]

The figure is an explanatory view showing a method for manufacturing a multilayer sliding member of the present invention. 1: Hoop material 2: FI4 back metal 3: Guide roller 4: Hosopa 5: M-water resin composition 6: Pressure roller 7: Hot air drying furnace 8: Pressure roller 9: Heating furnace 10: Adjustment roller 11: Cooling device

Claims (2)

[Claims] (1) A resin composition consisting of 5 to 40% by weight of addition polymerized polyimide resin, 0.1 to 10% by weight of graphite, and the balance of tetrafluoroethylene resin is applied to a porous sintered metal layer formed on a steel backing. A multilayer sliding member coated with impregnation. (2) (a) Grind 5 to 40% by weight of addition polymerized polyimide resin powder, 0.1 to 10% by weight of graphite powder, and the balance tetrafluoroethylene resin powder at a temperature below the room temperature transition point of the tetrafluoroethylene resin. (b) Adding 18 to 25 parts by weight of a petroleum solvent to 100 parts by weight of the obtained pulverized mixture and stirring and mixing at a temperature below the room temperature transition point to obtain a pulverized mixture; (c) supplying the wet resin mixture to a porous sintered metal layer formed by sintering metal powder on a backing plate made of a thin metal plate and applying the wet resin mixture to the porous sintered metal layer; impregnating and depositing the porous sintered metal layer; (d) drying the wet resin mixture impregnated and depositing on the porous sintered metal layer to remove the solvent; and (e) removing the resin. (f) heating and baking the resin mixture layer; (g) pressurizing the baked resin mixture layer while heating to reduce the adhesion thickness; (f) heating and baking the resin mixture layer; A method for manufacturing a multilayer sliding member, comprising: a step of adjusting; and the steps (a) to (g) above.