JP2006016670A - Copper-based friction member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper-based friction member with which the increase of temperature on the side of a brake caliper caused by high thermal conductivity is suppressed, and heat deterioration in rubber components such as vapor locks, boots and piston seals caused by the increase of brake liquid temperature can be prevented. <P>SOLUTION: In the copper-based friction member provided with a copper-based sintered friction material consisting mainly of copper powder and a pressure plate, a chemical nickel-plated zirconia powder layer is formed between the surface of the copper-based sintered friction material and the pressure plate. It is preferable that an alloy powder layer of copper and nickel is formed between the zirconia powder layer and the copper-based sintered friction member and/or an alloy powder layer of copper and nickel is formed between the zirconia powder layer and the pressure plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a copper-based friction member, and more particularly, to a copper-based friction member for a brake that suppresses a temperature increase on the brake caliper side and can prevent thermal damage.

  In general, organic materials are mainly used as brake friction materials, but copper-based sintered friction materials are used as brake friction materials with a large braking load such as the Shinkansen. As the speed of automobiles and railway vehicles increases, the use of copper-based sintered friction materials is expected to increase further in the future.

  By the way, the manufacturing process will be described by taking a disk brake pad as an example of a friction member. The pad is made of copper powder as a main component, and various kinds of metal and non-metal powders are added to the pad and homogenized with a stirrer. After mixing, the obtained powdery friction material base material is put into a preforming mold, and preforming is performed by compression molding at room temperature in order to approach a predetermined size and shape. Next, a pressure plate (hereinafter abbreviated as “P / P”) is applied to the preformed product obtained by this preforming step. That is, the friction material is naturally composed of a composition with an emphasis on the friction characteristics, but generally the mechanical strength is low, so that the P / P made of an iron-based material is also used to reinforce the strength in a copper-based sintered friction material. Be joined. For this reason, P / P manufactured in a separate process from the friction material, for example, punches a steel sheet into a predetermined shape, removes oil lipids from the metal surface of the processed product, degreases, and then performs a plating process. Manufactured. On the other hand, the preform is assembled by adding the P / P produced as described above, and then performing sintering. At the same time, the P / P is integrated into the main product to obtain a predetermined product. A sintering process is performed in which thermoforming is performed at pressure and temperature. Thereafter, the pad is manufactured by performing a finishing process such as a surface polishing process or a coating process.

  As described above, the copper-based sintered friction material must be manufactured with P / P separately from the formation of the friction material, and in addition, P / P must be subjected to a pretreatment such as copper plating. The number of manufacturing processes is large because the sufficient bonding strength between the P / P and the friction material cannot be ensured, and the process of positioning the friction material and the P / P is necessary prior to the sintering / bonding process. There were many problems with productivity. In addition, even if manufactured by the above process, there is a possibility that the friction material and P / P may cause poor bonding, and the friction material of copper-based material and P / P of iron-based material have a difference in thermal expansion. There was a concern that thermal deformation and thermal cracking would occur due to frictional heat during braking. In addition, copper-based friction materials have good thermal conductivity, so frictional heat is easily transmitted to the caliper via P / P, causing the brake fluid and rubber parts to rise in temperature and causing thermal damage. Accompanied by the inconvenience.

  Despite all these problems, copper-based sintered friction materials based on copper are superior in heat resistance compared to resin-based friction materials. Since a high coefficient of friction can be maintained even when the temperature of the material becomes high, it is widely used at present.

Also, in copper-based sintered friction materials formed by sintering with copper powder as the main component, friction characteristics such as mixing the materials necessary for friction characteristics such as graphite, ceramics, mica, etc. into the main copper powder A first layer formed by weight-dispersing and blending a material excellent in the above and the first layer, for example, the copper powder of the main material is promoted to the sintering in the subsequent sintering step, and sintered. It is composed of a second layer formed by mixing and stirring a phosphorous copper powder that contributes to strength improvement after sintering, and a material powder excellent in strength characteristics, and formed on the surface layer of the second layer. For example, the main material is zirconia powder, which is a main material, and has a low thermal conductivity and a hard material powder mixed with and stirred with phosphoric copper powder that acts as a binder in the sintering process with intervening zirconia particles. Brake that does not use P / P by forming a third layer that Friction member has been proposed (Patent Document 1). However, since this technique is for avoiding the use of P / P, it cannot be applied to a conventional copper-based sintered friction material premised on the use of P / P.
Japanese Patent Laid-Open No. 10-17854

  However, as explained above, since copper is used as the base material, the thermal conductivity is good, so the frictional heat generated during brake braking is easily transmitted to the brake caliper side via P / P and piston, and sudden braking is performed. In the case of severe use conditions that are repeated continuously, there is a concern about heat damage such as thermal deterioration of rubber parts such as vapor locks, boots, and piston seals due to an increase in brake fluid temperature.

  Therefore, as a method for preventing the frictional heat from being transmitted to the brake caliper side, a material having poor thermal conductivity is sprayed on the P / P surface, a heat insulating shim is inserted between the P / P and the piston, The use of materials with poor thermal conductivity, such as FRP (fiber reinforced resin) and ceramics, as P materials (generally used materials are low carbon steel with a surface plated with copper) is under consideration. .

  However, in the case of thermal spraying, there are problems in the cost increase due to an increase in the number of processes and the sustainability of the heat conduction suppressing effect due to poor adhesion with P / P. Moreover, the insertion of the heat insulation shim has a problem of cost increase due to the production of the heat insulation shim and an increase in the assembly process. In the case of P / P substitute materials, FRP has problems of increased strength, heat resistance, and increased costs due to increased material costs and processing costs, and ceramics due to increased reliability in bonding with sintered friction materials and increased material costs and processing costs. Significant cost increase becomes a problem.

  The present invention has been made in view of such circumstances, and the brake caliper side resulting from the high thermal conductivity of a copper-based sintered friction material based on copper (thermal conductivity: about 390 W / m · K). To provide a copper-based friction member, particularly a brake-based friction member that can prevent thermal deterioration of rubber parts such as vapor locks, boots, and piston seals due to an increase in brake fluid temperature. Objective.

  The present inventor conducted intensive research to achieve the above object, and between the molded body layer (copper-based sintered friction material) having excellent friction characteristics mainly composed of copper powder and P / P, It was found that heat damage caused by temperature rise of rubber parts and brake fluid does not occur if a zirconia powder layer with chemical nickel plating with lower thermal conductivity than copper is interposed and sintered. The invention has been achieved.

That is, in order to achieve the above object, the present invention has the following configuration.
(1) A zirconia powder obtained by applying chemical nickel plating between a copper-based sintered friction material and a pressure plate in a copper-based friction member including a copper-based sintered friction material and a pressure plate mainly composed of copper powder. A copper friction member characterized in that a layer is formed.
(2) The copper-based friction member according to (1), wherein an alloy powder layer of copper and nickel is formed between the zirconia powder layer and the copper-based sintered friction material.
(3) The copper-based friction member according to (1) or (2), wherein an alloy powder layer of copper and nickel is formed between the zirconia powder layer and the pressure plate.

The copper-based friction member of the present invention has a zirconia powder layer subjected to chemical nickel plating on the P / P side of a copper-based sintered friction material, and more preferably an alloy powder layer of copper and nickel above and below the zirconia powder layer. In particular, the copper-based friction member is preferably used as a friction member for brakes, but can also be used for applications other than brakes.
And since zirconia has a very low thermal conductivity (about 2 W / m · K), it is possible to prevent the heat of friction generated during brake braking from being transmitted to the P / P side and prevent thermal damage.
Moreover, a zirconia powder layer is formed by forming a solid solution of copper and zirconia with a total solid content, and having nickel (thermal conductivity: about 90 W / m · K) as the main component, which has a lower thermal conductivity than copper. Since it has an alloy powder layer of copper and nickel on the upper and lower sides, it has an excellent effect that the adhesion with P / P and copper-based sintered friction material whose surfaces are plated with copper does not deteriorate. In addition, it is known that copper and nickel will become a complete solid solution that dissolves at any composition ratio.

DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment when a copper friction member according to the present invention is used as a friction member for a brake will be described in detail with reference to the drawings.
In addition, this invention is not limited only to these embodiment.

  In the embodiment of the present invention, for example, as shown in the examples described later, a compounding material A containing copper powder is put into a preforming die to form a layer, and a 30 wt% Cu—Ni alloy, for example, is formed thereon. Powder B, zirconia powder having an average particle size of about 350 μm, powder C obtained by applying chemical nickel plating with a thickness of about 10 μm, and 30 wt% Cu—Ni alloy powder B are sequentially added and preformed to perform a preform. After obtaining P / P, P / P with copper plating on the surface is placed on the surface opposite to the blended material A of the preform and placed in a sintering furnace and sintered. The Cu-Ni alloy powder B layer, the powder C layer, the Cu-Ni alloy powder B layer, and the compounding material A layer (copper-based sintered friction material) are further laminated on the copper-plated layer. It is preferable to make a friction material having a configuration in which the A layer becomes a friction surface. As mentioned. Since the compounding material C layer, which is the powder C layer, has low thermal conductivity, the degree to which heat generated by friction is transmitted to P / P can be kept low.

  In the brake friction member having such a configuration, the reason for determining the configuration of each layer and the reason for interposing the intermediate layer will be described. The compounding material C layer is composed of zirconia powder subjected to chemical nickel plating. This is because the strength of the compounding material C layer cannot be ensured only with zirconia powder. The applied chemical nickel plating ensures the bonding strength of the compounding material C layer and the bonding strength with the copper-based sintered friction material (compounding material A layer) and P / P with copper plating on the surface. It is.

The provision of an alloy powder layer (mixed material B layer) of copper and nickel between the zirconia powder layer (mixed material C layer) subjected to chemical nickel plating and the copper-based sintered friction material (mixed material A layer) This is to make the bonding through chemical nickel plating more reliable.
An alloy powder layer (compounding material B layer) of copper and nickel is provided between the zirconia powder layer (compounding material C layer) subjected to chemical nickel plating and P / P whose surface is subjected to copper plating. This is to make the connection through nickel plating more reliable.

  In the above embodiment, as shown in FIG. 1, the compounding material C layer in which the compounding material B layer is formed on both sides between the copper-based sintered friction material (compounding material A layer) and P / P is provided. Although the copper-based friction member 1 for brakes interposed is described, as shown in FIG. 2, the compounding material B layer is interposed only between the compounding material A layer (copper-based sintered friction material) and the compounding material C layer. 1 and the case where only the compounding material C layer is interposed between the compounding material A layer (copper-based sintered friction material) and P / P shown in FIG. It has been found that it has the same excellent heat damage prevention and adhesiveness as the copper friction member.

  In other words, since zirconia has a very low thermal conductivity, it is possible to prevent thermal damage that suppresses the frictional heat generated during brake braking from being transmitted to the P / P side, and chemical nickel that forms a solid solution with copper in the zirconia powder. Since it is plated and has an alloy powder layer of copper and nickel above and below the zirconia powder layer, the adhesion to P / P and the copper-based sintered friction material does not decrease.

Example 1
(A) Manufacture of friction member for brake 1) Raw material Chemical material nickel having a thickness of about 10 μm on zirconia powder having an average particle size of about 350 μm, compounding material A shown in Table 1 and 30 wt% Cu—Ni alloy powder B Plating powder C was prepared.
2) Manufacture of preformed body After compounding material A was mixed, it was put into a preforming mold, and leveled and temporarily pressed. Next, the powder B was added over the powder B so as to be sprinkled uniformly, and then the powder C was added, followed by leveling and temporary pressing again. Subsequently, the compounding material B was poured again so as to be uniformly sprinkled, and then preformed at a molding pressure of 400 MPa to obtain a preformed body. In addition, the usage-amount of the powder B and the powder C was 1/20, 1/10 of the compounding material A by weight ratio.

3) Sintering process The surface on the opposite side to the compounding material A of the above preform and the P / P with copper plating on the surface are placed in a sintering furnace and maintained at a pressure of about 1 MPa and a temperature of 800 ° C. Sintering was performed for 2 hours.
4) Product The friction member for brake obtained by the sintering process is made into a product by polishing or the like, and the obtained product is P / P: 2 with copper plating on the surface as shown in FIG. On the copper plating side, there is a layer 5 of compounding material B, a layer 6 of compounding material C made of zirconia powder subjected to chemical nickel plating, and a layer 5 of compounding material B, next to compounding material A. The copper-based sintered friction material layer 4 has a structure.

(B) Friction test of product A friction test was carried out using the product of the present invention obtained in the above procedure and a comparative product produced without using powders B and C only with compounding material A, and the thickness of the friction material shown in FIG. The temperature at the center position X of 10 mm in thickness and the temperature at the center position Y of P / P thickness 6 mm is measured, and the results are shown in Table 2.
The temperature at the position Y of the product of the present invention was as low as 80 ° C. at the maximum as compared with the temperature at the position Y of the comparative product, and it was confirmed that it was effective in preventing thermal damage. The temperature at position X of the product of the present invention is almost the same as the temperature of position X of the comparative product, but in the present product, the temperature at position Y is lower than that of the comparative product due to the presence of powders B and C. It is confirmed that The friction test was performed by a test method based on a temperature-specific wear test using an inertial dynamo testing machine.

The conditions for temperature measurement at each position shown in Table 2 are as follows.
Condition 1: Friction material braking initial temperature 120 ° C
Condition 2: friction material braking initial temperature 200 ° C.
Condition 3: friction material braking initial temperature 250 ° C.
Condition 4: Friction material braking initial temperature 300 ° C.
Condition 5: friction material braking initial temperature 350 ° C.

(C) Adhesive strength test Moreover, when the adhesive strength between the friction material and P / P was measured for the product of the present invention and the comparative product, there was no significant difference at 45 to 48 MPa. The adhesive strength test was performed according to the JIS D4422 test method.

Example 2
This is because the P / P plated side has a layer of compounding material C as the first layer, the layer of compounding material B as the second layer, and the layer of compounding material A as the third layer (copper-based sintered friction) The structure is shown in FIG. The point which does not have the layer of the compounding material B as a 1st layer on the side which plated P / P differs from the friction member for brakes of Example 1. FIG.
Example 3
This has a layer of compounding material C as the first layer on the P / P plated side and a layer of compounding material A (copper-based sintered friction material) as the second layer. 3 shows. The point which does not have the layer of the compounding material B as a 1st layer and the layer of the compounding material B as a 3rd layer in the P / P plating side is different from the friction member for brakes of Example 1.

  The copper-based friction member of the present invention has reduced heat damage due to frictional heat, good adhesion between P / P and a copper-based sintered friction material, and improved wear resistance. It is particularly useful as a brake friction member for vehicles.

It is a figure which shows schematic structure and temperature measurement position of one Embodiment of the copper-type friction member for brakes which concerns on this invention. It is a schematic block diagram of another embodiment of the copper-type friction member for brakes which concerns on this invention. It is a schematic block diagram of another embodiment of the copper-type friction member for brakes which concerns on this invention.

Explanation of symbols

1 Copper friction member for brake 2 P / P
3 Copper plating layer 4 Compounding material A layer (copper-based sintered friction material)
5 Compounding material B layer (Alloy powder layer of copper and nickel)
6 Compounding material C layer (zirconia powder layer with chemical nickel plating)

Claims (3)

  Formed a zirconia powder layer with chemical nickel plating between a copper-based sintered friction material and a pressure plate in a copper-based sintered friction material with a copper-based sintered friction material and pressure plate containing copper powder as the main component A copper-based friction member.   The copper-based friction member according to claim 1, wherein an alloy powder layer of copper and nickel is formed between the zirconia powder layer and the copper-based sintered friction material.   The copper-based friction member according to claim 1, wherein an alloy powder layer of copper and nickel is formed between the zirconia powder layer and the pressure plate.

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