WO2018168967A1 - Multi-layered sliding member and method for producing same - Google Patents

Abstract

This multi-layered sliding member 1 comprises: a back metal 2; a porous metal sintered layer 4 integrally bonded to one surface 3 of the back metal 2; and a cover layer 7 filled in and covering pores 5 and a surface 6 of the porous metal sintered layer 4. The cover layer 7 comprises an addition-type thermosetting polyimide resin composed of: a polytetrafluoroethylene resin matrix phase; and 1-30 mass% of a bisallylnadiimide compound dispersedly contained in the polytetrafluoroethylene resin matrix phase.

Description

Multi-layer sliding member and manufacturing method thereof

The present invention relates to a multilayer sliding member having excellent friction and wear characteristics and a method for manufacturing the same.

Conventionally, tetrafluoroethylene resin (hereinafter referred to as “PTFE”) is excellent in self-lubricating properties, has a low coefficient of friction, and has chemical resistance and heat resistance, so it is widely used for sliding members such as bearings. Has been.

However, since the sliding member made of PTFE alone is inferior in wear resistance and load resistance, (a) a solid lubricant such as graphite and molybdenum disulfide and / or glass fiber, carbon, depending on the usage of the sliding member A reinforcing material such as fiber is contained in PTFE, or (b) the pores and the surface of the porous metal sintered layer backed by a steel backing metal are filled and covered with PTFE to compensate for the above-mentioned drawbacks.

The sliding member having the aspect (b) is a so-called multilayer sliding member. For example, Japanese Patent Publication No. 31-2452 (Patent Document 1), Japanese Patent Publication No. 39-16950 ( Patent Document 2), Japanese Patent Publication No. 41-1868 (Patent Document 3), and the like. These publications disclose a multi-layer sliding member in which the pores and the surface of a porous metal sintered layer lined with a steel back metal are covered with PTFE containing PTFE or a filler made of lead or lead oxide. Yes. In particular, lead as a filler is widely used to improve the wear resistance of sliding layers, but it must be abandoned from the secondary viewpoint of environmental pollution and pollution. It is in.

Japanese Patent Publication No.31-2452 Japanese Examined Patent Publication No. 39-16950 Japanese Patent Publication No.41-1868 Japanese Patent Laid-Open No. 2-6125

In view of the above circumstances, the present applicant selected addition polymerization type polyimide resin and graphite instead of fillers such as lead or lead oxide, and a porous PTFE composition containing these fillers formed on a steel backing metal. Japanese Unexamined Patent Publication No. 2-6125 (Patent Document 4) has proposed a multi-layer sliding member impregnated and deposited on a sintered metal layer. The multilayer sliding member proposed in Patent Document 4 always shows a stable coefficient of friction over a long period of time even when an addition polymerization type polyimide resin having a wide particle size distribution and a non-uniform particle size is used. It is excellent in wear resistance.

The multi-layer sliding member described in Patent Document 4 has excellent friction and wear characteristics and is therefore used for sliding applications in a wide range of fields such as automobile parts, electronic / electric parts, and general industrial machine parts. However, as the performance of parts in each field increases, the sliding member must be further improved in low friction and wear resistance.

The present invention has been made in view of the above points, and its object is to reduce the influence of wear resistance, particularly the surface roughness of the counterpart material, without sacrificing the low friction property of PTFE. Accordingly, it is an object of the present invention to provide a multilayer sliding member and a method for manufacturing the same, in which the abrasive wear resistance is greatly improved.

The multilayer sliding member of the present invention has a back metal, a porous metal sintered layer integrally bonded to one surface of the back metal, and a pore and a surface of the porous metal sintered layer filled and coated. The coating layer includes a PTFE matrix phase and an addition-type thermosetting polyimide resin made of a bisallylnadiimide compound dispersed and contained in the PTFE matrix phase at 1 to 30% by mass. It is out.

According to the multilayer sliding member of the present invention, the coating layer is reinforced by the addition type thermosetting polyimide resin made of the bisallyl nadiimide compound in which the matrix phase made of PTFE is dispersed and contained in the matrix phase. Therefore, the wear resistance can be greatly improved without sacrificing the low friction property of PTFE, and the abrasion wear (rough wear) resistance can be greatly improved.

In the multilayer sliding member of the present invention, the coating layer may contain phosphate as an additional component in a proportion of 1 to 15% by mass.

The method for producing a multilayer sliding member of the present invention includes (1) a step of integrally bonding a porous metal sintered layer to one surface of a back metal, and (2) an addition type heat comprising a bisallylnadiimide compound. 15-30 parts by mass of a petroleum solvent is blended with 100 parts by mass of the mixed powder obtained by mixing 1-30% by mass of the curable polyimide resin powder and the remaining PTFE powder as the matrix phase, and kneaded and wetted. A step of producing wettability-imparting mixed powder imparted with wettability; and (3) supplying and supplying the wettability-imparting mixed powder to the porous metal sintered layer, and rolling the wettability-imparting mixed powder with a roller to make the porous A step of filling the pores of the sintered metal layer with the wettability-imparting mixed powder and forming a coating layer having a uniform thickness on the surface of the porous sintered metal layer; and (4) obtained in the step (3). The backing metal provided with the coating layer on the surface of the sintered porous metal layer is reduced in advance. In a furnace heated to a temperature of at least 250 ° C., it is quickly dried in a short time of 2 to 3 minutes to completely volatilize and dissipate the petroleum solvent from the coating layer. A step of allowing the addition type thermosetting polyimide resin diffused in the matrix phase in the presence of a petroleum solvent to remain in the matrix phase of PTFE, and (5) the addition type thermosetting polyimide resin is made of PTFE. A step of rolling the back metal provided with a coating layer dispersedly contained in the matrix phase under pressure so as to have a predetermined thickness, and (6) a heating and firing furnace for the back metal processed in the step (5) And a step of heating and baking the coating layer.

According to the method for producing a multilayer sliding member of the present invention, in the step (4), the inside of the furnace in which the back metal provided with the coating layer on the surface of the porous metal sintered layer is heated to a temperature of at least 250 ° C. Each of the addition-type thermosetting polyimide resin powder particles dissolved in the petroleum-based solvent in the PTFE matrix phase by rapid drying in a short time in the PTFE Partly or entirely finely dispersed in the matrix phase, for example, the average particle size of the additive-type thermosetting polyimide resin powder in the mixed powder as seen from the laser micrograph (based on the laser diffraction / scattering method) The median diameter measured by a laser diffraction / scattering type particle size distribution analyzer is dispersed in the form of fine particles having a size about 1/100 to 1/20 of the particle size. Coating layer scan micronized addition type thermosetting polyimide resin in phase is formed by containing dispersed is formed. As a result, the matrix phase of PTFE forming the coating layer is reinforced by the addition type thermosetting polyimide resin finely divided and dispersed therein, so that the surface (sliding surface) of the coating layer and the counterpart material In the sliding friction, the PTFE matrix phase of the coating layer and the addition-type thermosetting polyimide resin dispersed and contained in the matrix phase become sliding friction, so the low friction property of PTFE is sacrificed. The wear resistance can be greatly improved without any problems.

According to the present invention, the wear resistance and the abrasive wear resistance can be greatly improved without sacrificing the low friction property of PTFE which is the main component of the coating layer. It is possible to provide a multilayer sliding member excellent in frictional wear characteristics and a method for manufacturing the same even under many different use conditions such as conditions.

FIG. 1 is an explanatory cross-sectional view of a multilayer sliding member of the present invention. FIG. 2 is an explanatory view showing an example of the manufacturing process of the multilayer sliding member of the present invention. FIG. 3 is an explanatory perspective view for explaining the thrust test method. FIG. 4 is an explanatory view of a micrograph showing a cross section of the coating layer of the present invention. FIG. 5 is an explanatory view of a photomicrograph showing a cross section of a coating layer of the prior art.

Next, preferred examples of the present invention and its embodiments will be described in detail. The present invention is not limited to these embodiments.

As shown in FIG. 1, a multilayer sliding member 1 of a preferred example of the present invention includes a backing metal 2 made of a steel plate, and a porous metal sintered layer 4 integrally joined to one surface 3 of the backing metal 2. The porous metal sintered layer 4 has a pore 5 and a coating layer 7 filled and coated on the surface 6. The coating layer 7 has a PTFE matrix phase and a PTFE matrix phase of 1 to 30% by mass. And an addition-type thermosetting polyimide resin made of a bisallylnadiimide compound dispersedly contained.

In the coating layer 7 in the multilayer sliding member of the present invention, PTFE mainly used for molding as fine powder is used as the PTFE constituting the main component. Fine powders include “Polyflon F201 (trade name)” manufactured by Daikin Industries, Ltd., “Teflon (registered trademark) 6CJ (trade name)” manufactured by Mitsui DuPont Fluorochemicals, Inc., and “ “Full-on CD097E (trade name)”.

Addition-type thermosetting polyimide resin blended with PTFE is synthesized from allyl nadic acid anhydride and diamine, and a bisallyl nadiimide compound having an allyl group at both ends is used by dehydration ring-closing reaction. It is represented by

　（式中、Ｒは下記一般式（ＩＩ）又は（ＩＩＩ）で表される官能基である。）

(In the formula, R is a functional group represented by the following general formula (II) or (III).)

The bisallylnadiimide compound containing the functional group of the general formula (II) in the bisallylnadiimide compound represented by the general formula (I) is composed of N, N′-4,4′-diphenylmethanebisallyldiimide. As a commercial product of this bisallylnadiimide compound, “BANI-M (trade name)” manufactured by Maruzen Petrochemical Co., Ltd. may be mentioned. The bisallylnadiimide compound containing the functional group of the general formula (III) in the bisallylnadiimide compound represented by the general formula (I) is composed of N, N′-m-xylenebisallylnadiimide, A commercially available product of this bisallyl nadiimide compound is “BANI-X (trade name)” manufactured by Maruzen Petrochemical Co., Ltd.

The above-mentioned addition type thermosetting polyimide resin has particles having an average particle diameter of 20 μm, and the amount of addition type thermosetting polyimide resin blended with PTFE is 1 to 30% by mass, preferably 10 to 15% by mass. If the blending amount is less than 1% by mass, the reinforcing effect of the addition-type thermosetting polyimide resin is not sufficient, the effect of improving the wear resistance and the abrasive wear resistance is not exhibited, and the blending amount exceeds 30% by mass. The amount of addition-type thermosetting polyimide resin fine particles dispersed in the matrix phase of PTFE and PTFE increases, and the ratio of direct exposure to the surface (sliding surface) of the coating layer increases. In addition to impairing the wear resistance, the wear resistance may be reduced. The average particle diameter in the present invention is a median diameter measured by a laser diffraction / scattering type particle size distribution measuring apparatus based on the laser diffraction / scattering method. *

In the multilayer sliding member of the present invention, phosphate may be blended in an amount of 1 to 15% by mass as an additional component in the main component PTFE and the addition type thermosetting polyimide resin.

Phosphate itself is not a substance exhibiting lubricity such as solid lubricants such as graphite and molybdenum disulfide, but by blending with PTFE, the surface of the mating material (sliding) It promotes the film-forming property of the PTFE lubrication film on the moving surface), and is effective in improving the wear resistance of the coating layer. Can be applied to the intended use.

By adding a small amount of phosphate, for example, 1% by mass to PTFE, an effect of promoting the film forming property of the lubricating coating described above starts to appear, and the effect is maintained up to 15% by mass. However, if it exceeds 15% by weight, the amount of lubricating coating formed on the surface of the counterpart material becomes too large, and the wear resistance is reduced. Therefore, the amount of the phosphate is 1 to 15% by mass, preferably 5 to 10% by mass.

Preferred examples of the phosphate include a metal salt selected from any one of the group of metal salts of diphosphate, tertiary phosphate, pyrophosphate and metaphosphate, and mixtures thereof. be able to. Of these, metal salts of pyrophosphoric acid and metaphosphoric acid are preferable. As the metal, an alkali metal and an alkaline earth metal are preferable, and lithium (Li), calcium (Ca), and magnesium (Mg) are particularly preferable. Specifically, lithium triphosphate (Li ₃ PO ₄ ), tricalcium phosphate [Ca ₃ (PO ₄ ) ₂ ], calcium hydrogen phosphate [CaHPO ₄ .2H ₂ O] or anhydride (CaHPO ₄ ), Magnesium hydrogen phosphate (MgHPO ₄ .3H ₂ O) or anhydride (MgHPO ₄ ), lithium pyrophosphate (Li ₄ P ₂ O ₇ ), calcium pyrophosphate (Ca ₂ P ₂ O ₇ ), magnesium pyrophosphate (Mg ₂ P ₂ O ₇ ), lithium metaphosphate (LiPO ₃ ), calcium metaphosphate [Ca (PO ₃ ) ₂ ] and magnesium metaphosphate [Mg (PO ₃ ) ₂ ].

Next, a method for manufacturing the multilayer sliding member of the present invention will be described.

As the steel plate as the backing metal, a general structural rolled steel plate (SS400 or the like) specified in JISG3101 or a cold rolled steel plate (SPCC) specified in JISG3141 is used. It is preferable to use a continuous strip provided as a hoop material by winding it in a coil shape, but it is not necessarily limited to a continuous strip, and a strip cut to an appropriate length can also be used. These strips may be subjected to copper plating or nickel plating as necessary to improve the corrosion resistance. The thickness of the steel plate as the backing metal is preferably about 0.5 to 1.5 mm.

The metal powder forming the porous metal sintered layer that is integrally joined to one surface of the back metal plate made of the steel plate, the metal itself, such as bronze, lead bronze or phosphor bronze excellent in friction and wear characteristics, Copper alloy powder that passes 100 mesh is used, but powders other than copper alloy, such as aluminum alloy and iron, may be used depending on the purpose. The metal powder may be in the form of a lump, a sphere, or an irregular shape. This porous metal sintered layer must be firmly bonded to the alloy powder and the strips such as the steel plate, and to have a certain thickness and the required porosity. The thickness of the porous metal sintered layer 4 is preferably about 0.15 to 0.40 mm, more preferably 0.2 to 0.3 mm, and the porosity is about 10% by volume or more, especially 15 It is recommended to be ~ 40% by volume.

The mixed powder to be filled and coated on the pores and the surface of the porous metal sintered layer of the multi-layer sliding member is an addition-type thermosetting composed of PTFE powder and a bisallylnadiimide compound having an average particle size of 20 μm as a filler. This is obtained by mixing the polyimide resin powder or the addition type thermosetting polyimide resin powder and the phosphate powder, and adding the petroleum solvent to the resulting mixed powder and stirring and mixing the mixture. A wettability is imparted to the powder. The mixing of the PTFE powder and the filler is performed at a temperature not higher than the room temperature transition point (19 ° C.) of PTFE (19 ° C.), preferably 10 to 18 ° C. Is performed at the same temperature. By adopting such a temperature condition, fiber formation of PTFE can be suppressed, and a uniform wettability imparted mixed powder can be obtained.

As the petroleum solvent, in addition to naphtha, toluene, and xylene, aliphatic hydrocarbon solvents such as paraffinic and naphthenic solvents or mixed solvents thereof are used. The ratio of the petroleum solvent used is 15 to 30 parts by mass with respect to 100 parts by mass of the mixed powder of PTFE powder and filler. When the proportion of the petroleum solvent used is less than 15 parts by mass, the extensibility of the wettability-imparting mixed powder to which wettability is imparted is poor in the pore and surface filling and coating step of the porous metal sintered layer described later. As a result, there is a possibility that unevenness is likely to occur in the filling coating on the porous metal sintered layer. On the other hand, when the proportion of the petroleum-based solvent exceeds 30 parts by mass, not only the filling and coating operation becomes difficult, but also the uniformity of the coating thickness of the wettability imparting mixed powder is impaired, There is a possibility that the adhesion strength between the resulting coating layer and the porous metal sintered layer will deteriorate. Specific examples of the petroleum solvent include “Exol (trade name)” manufactured by Exxon Chemical Co., which is a naphthenic solvent, “Isopar (trade name)” manufactured by Exxon Chemical Co., which is an isoparaffin solvent.

The multilayer sliding member of the present invention is manufactured through the manufacturing steps (a) to (d) shown in FIG.

(A) The backing metal 2 integrally joined with the porous metal sintered layer 4 supplied as the hoop material 8 wound in a coil shape is fed forward by the guide rollers 9 and 9, and the porous metal firing of the backing metal 2 is performed. The wettability-imparting mixed powder 11 imparted with the wettability contained in the hopper 10 is sprayed and supplied onto the surface 6 of the binder layer 4, and then rolled with the pressure rollers 12 and 12 to be sintered in the porous metal sintered layer 4. The coating layer 7 made of the wettability imparting mixed powder having a uniform thickness is formed on the surface 6 of the porous metal sintered layer 4. In this step, the thickness of the coating layer 7 is 2 to 2.2 times the thickness of the coating layer required for the final product. Most of the filling of the wettability imparting mixed powder into the pores 5 of the sintered porous metal layer 4 proceeds in this step.

(B) Furnace 13 in which the back metal 2 provided with the coating layer 7 of wettability imparting mixed powder on the surface 6 of the sintered porous metal layer 4 treated in the step (a) is heated to a temperature of at least 250 ° C. in advance. Within a short time, for example 2-3 minutes, drying rapidly. By rapidly drying, each of the addition-type thermosetting polyimide resin powder having an average particle size of 20 μm contained in the PTFE matrix phase of the coating layer 7 is partially or wholly in the presence of a petroleum solvent. Thus, the addition type thermosetting polyimide resin diffused as fine particles is dispersed in the matrix phase of PTFE by diffusing in the matrix phase as fine particles and then the petroleum solvent completely volatilizes and escapes. Remains. In this drying step, the addition-type thermosetting polyimide resin becomes fine particles having a size about 1/100 to 1/20 of that of the addition-type thermosetting polyimide resin having an average particle diameter of 20 μm. It is diffused and contained in the matrix phase of PTFE. In this drying process, it is not clear why the addition type thermosetting polyimide resin powder is dispersed in the PTFE matrix phase in the form of fine particles. It is inferred that the addition type thermosetting polyimide resin powder was dissolved in the solvent and dispersed in the matrix phase. After the drying step, the dried coating layer 7 is subjected to a pressure roller treatment under a pressure of 29.4 to 58.8 MPa (300 to 600 kgf / cm ² ) so as to have a predetermined thickness by the pressure rollers 14 and 14. .

(C) After the back metal 2 treated in the step (b) is introduced into the heating and firing furnace 15 and heated at a temperature of 360 to 380 ° C. for several minutes to 10 several minutes to perform firing, the back metal 2 is After passing through the heating and firing furnace 15, the coating layer 7 is completely fired and cured. Subsequently, the back metal 2 is adjusted in dimensional variation by roller processing by the dimensional adjusting rollers 16 and 16 and finely adjusted in the thickness of the coating layer 7.

(D) The back metal 2 adjusted in the above step (c) is passed through the cooling device 17 by spraying cold water or the like to cool the back metal 2 to room temperature. Thereafter, in order to correct the waviness of the back metal 2 as necessary, the correcting roller device 18 performs a correction roller process to correct slight waviness of the back metal 2. Next, the straightened back metal 2 is fed forward by the guide rollers 19 and 19 and wound around the coiler 20.

In the multilayer sliding member obtained through the steps (a) to (d), the porous metal sintered layer has a thickness of 0.10 to 0.40 mm, and the coating layer has a thickness of 0.02 to It is set to 0.20 mm. The multilayer sliding member obtained in this way is cut to an appropriate size and used as a sliding plate in a flat plate state, or rounded and used as a cylindrical wound bush.

According to the above production method, the addition-type thermosetting polyimide resin powder is dispersed and contained in the PTFE matrix phase in the form of fine particles having a size of 0.2 to 1.0 μm. Since the coating layer 7 in which the fine particles of the addition-type thermosetting polyimide resin are dispersed is formed, the PTFE matrix phase forming the coating layer 7 is reinforced by the addition-type thermosetting polyimide resin in which the dispersion is contained, In the sliding friction between the surface (sliding surface) of the coating layer 7 and the counterpart material, the sliding friction is between the PTFE matrix phase of the coating layer 7 and the addition-type thermosetting polyimide resin dispersed and contained in the matrix phase. Therefore, the wear resistance can be greatly improved without sacrificing the low friction property of PTFE.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, the sliding characteristics of the multilayer sliding member were evaluated by the following test method.

<Thrust test>
Test method: Under the conditions shown in Table 1, as shown in FIG. 3, a rectangular bearing test piece (multi-layer sliding member) 21 having a side of 30 mm is fixed to a test table, and a cylindrical body as a counterpart material The cylindrical body 22 is rotated around the axis 24 of the cylindrical body 22 in the direction Y while applying a predetermined load in the direction X perpendicular to the surface 23 to one surface 23 of the bearing test piece 21 from 22. The friction coefficient between the bearing test piece 21 and the cylindrical body 22 and the wear amount of the surface 23 of the bearing test piece 21 after the test were measured. As for the friction coefficient, the friction coefficient at the time of stability until the end of the test after 1 hour from the start of the test is shown, and the wear amount is shown by the dimensional change amount of the sliding surface after 20 hours of the test time. .

[Table 1]
Sliding speed 3m / min
Load 29.4 MPa (300 kgf / cm ² )
Test time 20 hours Lubrication Unlubricated counterpart material Carbon steel for machine structure (S45C)
Opposite material surface roughness Ra0.05, Ra0.15, Ra0.30, Ra0.50

In the following examples, the following materials were used for PTFE, addition-type thermosetting polyimide resin, phosphate, graphite, and backing metal.
<PTFE>
"Polyflon F201 (trade name)" manufactured by Daikin Industries
<Additional thermosetting polyimide resin: average particle size 20 μm>
(1) BANI-M N, N'-4,4'-diphenylmethanebisallylnadiimide manufactured by Maruzen Petrochemical Co., Ltd. (2) BANI-X N, N'-m-xylenebisallylna manufactured by Maruzen Petrochemical Co., Ltd. Diimide <Phosphate>
(1) Calcium pyrophosphate (2) Magnesium metaphosphate <Graphite>
CB150 Natural graphite powder with an average particle size of 40 μm manufactured by Nippon Graphite Co., Ltd. <Back metal>
Back metal including a steel plate having a thickness of 0.70 mm and a porous metal sintered layer made of a bronze alloy having a thickness of 0.25 mm and integrally joined to one surface of the steel plate

Examples 1-27
PTFE powder and the fillers shown in Tables 2 to 8 are fed into a Henschel mixer and stirred and mixed, and 25 parts by mass of a petroleum solvent is blended with 100 parts by mass of the obtained mixed powder to obtain a room temperature of PTFE. Mixing was performed at a temperature below the transition point (15 ° C.) to obtain a wettability imparted mixed powder imparted with wettability.

The wettability-imparting mixed powder imparted with wettability is sprayed and supplied onto the porous metal sintered layer of the backing metal, and is rolled with a roller so that the wettability-imparting mixed powder has a thickness of 0.20 mm. A multilayer plate provided with a coating layer formed by filling and coating the wettability imparting mixed powder on the pores and the surface of the sintered metal layer was obtained. The multi-layer plate was kept in a drying furnace preheated to a temperature of 280 ° C. for 3 minutes to rapidly dry the coating layer. Next, the dried coating layer was rolled with a roller at a pressure of 400 kgf / cm ² so that the thickness of the coating layer coated on the surface of the porous metal sintered layer was 0.15 mm.

Next, the pressure-treated multilayer board is heated and fired at 370 ° C. for 10 minutes in a heating furnace, and then again subjected to pressure treatment with a roller to adjust dimensions and correct waviness to produce a multilayer sliding member. did. The multilayered sliding member after the correction was cut to obtain a multilayered sliding member test piece having a side of 30 mm.

Comparative Examples 1 to 3
PTFE powder and the filler shown in Table 8 are supplied into a Henschel mixer and mixed by stirring. 25 parts by mass of a petroleum solvent is blended with 100 parts by mass of the obtained mixed powder, and the temperature is below the room temperature transition point of PTFE. Were mixed at a temperature of 15 ° C. to obtain a wettability imparted mixed powder imparted with wettability.

Thereafter, in the same manner as in the above example, a multilayer plate in which the pores and the surface of the porous metal sintered layer were filled and coated with wettability-imparting mixed powder was obtained. The obtained multilayer board was kept in a hot air drying furnace heated to a temperature of 150 ° C. for 10 minutes to form a coating layer that volatilized and escaped the petroleum solvent, and then the dried coating layer was applied with a pressure of 400 kgf / The thickness of the coating layer rolled on cm ² and coated on the surface of the porous metal sintered layer was set to 0.15 mm. Next, the multilayer sliding member produced in the same manner as in the above example was cut to obtain a multilayer sliding member test piece having a side of 30 mm.

In the test results of the sliding characteristics of the multilayer sliding members of Comparative Examples 1 to 3 in Table 7 above, the friction coefficient of the surface roughness Ra0.50 of the counterpart material suddenly increased during the test, and the friction coefficient was The test was stopped because it exceeded 0.25 (indicated by *). After the test, it was observed that the sintered layer was exposed and the wear reached the sintered layer. The amount of wear measured was the amount of wear (indicated by *) when the test was stopped.

From the test results, the multilayer sliding member of the example of the present invention exhibited stable performance throughout the test time, had very little wear, and had excellent sliding characteristics. In the multilayer sliding member of the example, it was confirmed that the addition-type thermosetting polyimide resin was dispersed and contained in the matrix phase of PTFE forming the coating layer. FIG. 4 is a cross-sectional micrograph of the coating layer of the multi-layer sliding member of Example 5. In FIG. 4, reference numeral 7 is the coating layer, reference numeral 25 is the surface of the coating layer 7, and reference numeral 26 is the matrix phase of PTFE. Reference numeral 27 denotes an addition type thermosetting polyimide resin (BANI-M) dispersed and contained as fine particles in the matrix phase 26 of the PTFE. 5 is a cross-sectional photomicrograph of the coating layer of the multilayer sliding member of Comparative Example 2. In FIG. 5, reference numeral 7 is the coating layer, reference numeral 25 is the surface of the coating layer 7, and reference numeral 26 is PTFE. Reference numeral 28 denotes a matrix phase, addition type thermosetting polyimide resin (BANI-M) dispersed and contained in the matrix phase of PTFE, and reference numeral 29 denotes graphite dispersed and contained in the matrix phase 26 of PTFE. Comparing the cross-sectional micrographs of the coating layer of FIGS. 4 and 5, in FIG. 4 showing the coating layer of the multilayer sliding member of the present invention, the addition-type thermosetting polyimide resin contains fine particles in the matrix phase of PTFE. It turns out that it is dispersed and contained. The addition-type thermosetting polyimide resin is finely dispersed and contained in the PTFE matrix phase to reinforce the PTFE matrix phase and to form a good lubricating film (transfer film) on the surface of the counterpart material. Therefore, it is considered that the influence of the surface roughness of the counterpart material can be reduced, and the wear resistance can be greatly improved without sacrificing the low friction property of PTFE.

Furthermore, in the multilayer sliding members of Examples 11 to 27 containing phosphate in the component, the formation of a PTFE coating on the surface of the counterpart material was promoted, and further excellent sliding characteristics were exhibited. Inferred.

On the other hand, the multilayer sliding member of the comparative example volatilizes and dissipates the petroleum solvent over a period of 10 minutes at a low temperature of 150 ° C. unlike the normal drying process, that is, the example of the present invention. As shown in FIG. 5, the addition-type thermosetting polyimide resin becomes fine particles in the presence of a petroleum solvent and is not dispersed and contained in the PTFE matrix phase as in the embodiment of the present invention. It seems that it remained in the matrix phase of PTFE. For this reason, the reinforcing effect of the addition-type thermosetting polyimide resin contained in the matrix phase is not sufficient, and a good lubricating film is not formed on the surface of the counterpart material. As the surface roughness of the mating material becomes higher, the friction coefficient becomes higher and the wear amount becomes larger, which seems to result in inferior sliding properties.

As described above, according to the present invention, the wear resistance, in particular, the influence of the surface roughness of the mating material can be reduced without sacrificing the low friction property of the PTFE matrix phase of the coating layer, and the abrasion resistance can be reduced. It is possible to provide a multi-layer sliding member and a method for manufacturing the same which have greatly improved performance.

DESCRIPTION OF SYMBOLS 1 Multi-layer sliding member 2 Back metal 3 Surface 4 Porous metal sintered layer 5 Pore 6 Surface 7 Covering layer

Claims (8)

Multi-layer sliding member comprising a backing metal, a porous metal sintered layer integrally joined to one surface of the backing metal, and a coating layer filled and coated on the pores and the surface of the porous metal sintered layer The coating layer is an addition type thermosetting polyimide comprising a matrix phase of tetrafluoroethylene resin and a bisallylnadiimide compound dispersed and contained in the matrix phase of tetrafluoroethylene resin at 1 to 30% by mass. A multilayer sliding member containing a resin. The multilayer sliding member according to claim 1, wherein the bisallylnadiimide compound comprises N, N'-4,4'-diphenylmethanebisallylnadiimide. The multilayer sliding member according to claim 1, wherein the bisallylnadiimide compound comprises N, N'-m-xylenebisallylnadiimide. The multi-layer sliding member according to any one of claims 1 to 4, wherein the coating layer contains a phosphate in an amount of 1 to 15% by mass as an additional component. (1) a step of integrally bonding the porous metal sintered layer to one surface of the back metal;
(2) To 100 parts by mass of a mixed powder obtained by mixing 1 to 30% by mass of an addition-type thermosetting polyimide resin powder composed of a bisallylnadiimide compound and the remaining tetrafluoroethylene resin powder as a matrix phase A step of blending 15 to 30 parts by mass of a petroleum solvent and kneading to give a wettability-providing mixed powder;
(3) The wettability imparting mixed powder is sprayed and supplied to the porous metal sintered layer, and the wettability imparting mixed powder is rolled with a roller to fill the pores of the porous metal sintered layer with the wettability imparting mixed powder. And forming a coating layer made of the wettability-imparting mixed powder having a uniform thickness on the surface of the porous metal sintered layer;
(4) Rapidly in a short time of 2 to 3 minutes in a furnace in which the back metal provided with the coating layer on the surface of the porous metal sintered layer obtained in the step (3) is heated to a temperature of at least 250 ° C. And the coating layer is completely volatilized to dissipate the petroleum solvent, and the complete volatilization of the petroleum solvent diffuses into the matrix phase in the presence of the petroleum solvent. A step of leaving the polyimide resin in the matrix phase;
(5) a step of subjecting the back metal provided with a coating layer in which the addition-type thermosetting polyimide resin is dispersedly contained in the matrix phase to a predetermined thickness, and roller treatment under pressure,
(6) A method for producing a multilayer sliding member, comprising: introducing the back metal treated in the step (5) into a heating and baking furnace and heating and baking the coating layer. The method for producing a multilayer sliding member according to claim 5, wherein the bisallylnadiimide compound comprises N, N'-4,4'-diphenylmethanebisallylnadiimide. The method for producing a multi-layer sliding member according to claim 5, wherein the bisallylnadiimide compound comprises N, N'-m-xylenebisallylnadiimide. The method for producing a multilayer sliding member according to any one of claims 5 to 7, wherein the mixed powder contains a phosphate powder in an amount of 1 to 15% by mass as an additional component.

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