JP2010270768A - Adhesion method of brake lining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adhesion method for improving joining strength between an adhesive surface of a pressure plate 6a and a lining 7a. <P>SOLUTION: After cleaning the pressure plate 6a, a large number of fine conical projections are formed by sputter-etching on the adhesive surface being a surface for adhering the lining 7a among the pressure plates 6a. Afterwards, after applying an adhesive to the adhesive surface after applying phosphate treatment, the lining 7a is adhered and fixed to the adhesive surface while being heated, pressurized and molded. Since a large anchor effect can be obtained by respective conical projections, the joining strength is improved. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an improvement in a method for adhering and fixing a lining constituting a brake pad for a disc brake, for example, to a pressure plate, and aims to realize an adhering method capable of obtaining a large adhesive strength.

  Conventionally, for example, disk brakes described in Patent Documents 1 and 2 are known as brakes for braking a vehicle such as an automobile. 4-5 has shown the disc brake described in patent document 1 among these. This disc brake includes a support 1, an inner pad 2 and an outer pad 3, and a caliper 4. Both the inner and outer pads 2 and 3 are held by the pad holding portion of the support 1 so as to be able to be displaced in the axial direction of the rotor 5 (front and back direction in FIG. 4 and vertical direction in FIG. 5). Further, these pads 2 and 3 are respectively fixed by attaching linings 7 and 7 as friction materials on the front surfaces (surfaces facing each other) of the pressure plates 6 and 6 as reinforcing plates described in the claims. Become. When braking, hydraulic pressure is introduced into the cylinder portion 8 of the caliper 4, and the lining 7 of the inner pad 2 is placed on the inner side surface of the rotor 5 by the piston 9 and the lining 7 of the outer pad 3 is placed on the rotor 5. Press against the outer surface of each.

  The pressure plates 6 and 6 constituting both the pads 2 and 3 are made of steel plates to ensure sufficient strength and rigidity. The linings 7 and 7 are made of, for example, sintered metal or the like as a material that can ensure the coefficient of friction with the side surface of the rotor 5 and the required wear resistance. The pressure plates 6 and 6 and the linings 7 and 7 are fixed by adhesion. However, a large shearing force is applied to the joint surface between the pressure plates 6 and 6 and the linings 7 and 7 during braking. Will be added. That is, a large force (brake torque) in the rotational direction of the rotor 5 is applied to the linings 7 and 7 along with friction with the side surface of the rotor 5, whereas the pressure plates 6 and 6 It is held by the support 1 and tries to stop at the same position. As a result, the large force is applied to the joint surface.

  Regardless of such a large force, in order to prevent damage such as peeling on the joint surface, it has been conventionally applied to a part of the pressure plate 6a as shown in FIGS. The locking holes 10 and 10 are formed, and the locking projections 11 and 11 that fit into the locking holes 10 and 10 are provided on a part of the lining 7a. And based on the mechanical engagement of each of these locking holes 10 and 10 and each of these locking projections 11 and 11, the resistance against the large force is improved, and the joint surface between the pressure plate 6a and the lining 7a In order to prevent the above-mentioned damage from occurring. On the other hand, as shown in FIG. 3 showing the embodiment of the present invention, it is also widely practiced that the pressure plate 6b and the lining 7b are bonded and fixed only by adhesion without providing a locking hole in the pressure plate 6b. It has been broken.

  In any of the brake pads 12a and 12b shown in FIGS. 1 to 3, the pressure plates 6a and 6b and the lining 7a, It is important to ensure sufficient adhesive strength with 7b. Therefore, conventionally, the lining is bonded and fixed to a metal plate (steel plate) constituting the pressure plate in the following process. First, this metal plate is subjected to degreasing treatment → cleaning → chemical conversion treatment in sequence, and then a primer treatment and a baking treatment are performed on the surface on which one side of the metal plate is to be bonded (hereinafter referred to as an “adhesion surface”). Apply adhesive. Thereafter, the preformed material of the lining is superimposed on the pressure plate and pressed while being heated, so that the material is compression-molded to form the lining, and at the same time, is bonded to the pressure plate.

  By bonding and fixing the lining and the pressure plate in this manner, sufficient bonding strength between the lining and the pressure plate can be ensured under general use conditions. In particular, as in the structure shown in FIGS. 1 and 2, if the locking holes 10 and 10 on the pressure plate 6a side and the locking projections 11 and 11 on the lining 7a side are mechanically engaged, the rotation direction It is possible to further improve the resistance to a large force that is suitable for. However, in order to ensure sufficient reliability and durability even under more severe use conditions, it is desired to further improve the bonding strength.

  In view of such circumstances, Patent Document 3 discloses that, prior to bonding with the lining, rust is removed from the bonding surface of the pressure plate by shot blasting or barrel processing, and at the same time, the bonding surface has a height in advance. It describes that irregularities of 5 to 50 μm are formed. The adhesive surface of the pressure plate having such irregularities is coated with a phosphate metal film, further subjected to a primer treatment, and then the lining is bonded with an adhesive.

  According to such a bonding method as described in Patent Document 3, the resistance to a large force in the rotational direction can be improved to some extent by the anchor effect (mechanical engagement) of the unevenness. However, there is still room for improvement in terms of ensuring reliability and durability under severe use conditions. For example, during use in a coastal area, minute separation occurs at the end of the joint surface between the lining and the pressure plate, and rust is generated on the pressure plate at this part, and separation progresses with the volume expansion of this rust. there's a possibility that. In such a situation, since the large force is applied to the remaining joint portion, it is desirable to increase the bonding strength of the joint portion as much as possible. In the case of the prior art described in Patent Document 3, the unevenness is made by shot blasting or barrel processing, and is relatively smooth, so the anchor effect is low, and the adhesive strength of the joint surface Is not necessarily improved sufficiently.

JP-A-5-44751 Japanese Patent Laid-Open No. 10-54431 JP-A-5-346129

  In view of the above-described circumstances, the present invention has been invented to realize a brake lining bonding method capable of improving the bonding strength between a bonding surface of a reinforcing plate such as a pressure plate and a lining.

The method for bonding a brake lining according to the present invention is a method for bonding and fixing a lining that frictionally engages with a braking rotor during braking to a reinforcing plate.
In particular, in the method for bonding a brake lining according to the present invention, after cleaning the reinforcing plate, a large number of fine conical protrusions are formed by sputter etching on at least the bonding surface to which the lining is to be bonded. Form. Each of these conical protrusions has a diameter (0.5 μm or more) of 1.0 μm or less and a height of 0.5 to 1.0 μm as in the invention described in claim 2, Form densely. After forming such a conical protrusion, the adhesive surface is subjected to a phosphate treatment and then an adhesive is applied, and then the lining is bonded and fixed to the adhesive surface while being heated and pressure-molded.
In addition, the phosphating is performed by degreasing and cleaning the adhesive surface (removing an adhesion inhibitor) and increasing the surface tension of the adhesive surface (improving the wettability with the adhesive). This is done to improve the adhesion. As the phosphate for the phosphate treatment performed for such a purpose, zinc phosphate and iron phosphate can be used. When the reinforcing plate such as the pressure plate is a steel plate, iron phosphate is used. It is preferable to use it. As the adhesive, either a solvent type or a powder type can be used.

  In the process of the bonding method of the present invention, a large number of fine conical projections formed on the bonding surface of a reinforcing plate such as a pressure plate are formed on the unevenness formed on the bonding surface in the case of the invention described in Patent Document 3 described above. Compared with a sharp (pointed) shape, it is densely formed (the number per unit area increases). That is, by irradiating an ion beam to a work surface (adhesion surface), atoms existing on the work surface are sputtered to etch the work surface, and according to sputter etching, a sharp cone is formed on the adhesion surface. The protrusions can be formed densely. Further, on the inner surface of the lining (the surface that comes into contact with the bonding surface), minute concave holes that are closely fitted to the conical protrusions are formed in the process of bonding and fixing the lining while being pressure-molded. For this reason, the conical protrusions and the minute concave holes are in mesh with each other at the joint surface between the adhesive surface of the reinforcing plate and the inner surface of the lining. Moreover, the inclination angle of the peripheral surfaces of the conical protrusions and the minute concave holes with respect to the surface direction of the joint surface is steep compared to the unevenness in the invention described in Patent Document 3. Thus, in the case of the brake pad (or brake shoe) manufactured by the manufacturing method of the present invention, a large number of minute protrusions and a large number of minute concave holes are engaged at a steep angle with respect to the direction of the force. The anchor effect on the force acting in the surface direction of the joint surface is increased. As a result, the reliability and durability of the brake pad (or brake shoe) can be sufficiently ensured even under extremely severe use conditions.

The perspective view which shows the 1st example of the brake pad used as the object of the manufacturing method of this invention in the state seen from the back side of the pressure plate. The expanded AA sectional view of FIG. The perspective view which shows the 2nd example of the brake pad used as the object of the manufacturing method of this invention in the state seen from the back side of the pressure plate. The orthographic projection figure which shows one example of conventional structure in the state which cut | disconnected the left half part and was seen from the outer side. The orthographic projection figure which shows the state which cut the part similarly and was seen from the outer diameter side.

An experiment conducted for confirming the effect of the present invention will be described. In this experiment, as described below, three types of test pieces (Examples 1 to 3) belonging to the technical scope of the present invention and two types of test pieces (comparative examples) deviating from the technical scope of the present invention. A total of five types of test pieces, 1 and 2), were prepared.
[Example 1]
As shown in FIGS. 1 and 2, after the steel plate pressure plate 6a having a plurality of (four in the actual case) locking holes 10 and 10 is degreased with an organic solvent, this pressure plate is formed by sputter etching. Numerous fine protrusions were formed on the adhesive surface (front surface) of 6a. The inner diameter of each of the locking holes 10 and 10 was 16 mm.
Next, this adhesive surface was subjected to iron phosphate treatment for improving adhesiveness with the adhesive, and then the adhesive was applied. As this adhesive, a polyvinyl butyral modified phenolic resin, which is a solvent-type adhesive, was used.
After the adhesive is applied, the adhesive is dried by allowing it to stand at room temperature for 48 hours, and then a preformed lining material is superimposed on the adhesive surface of the pressure plate 6a and heated at 160 ° C. at 50 MPa. This material is compression-molded to form a lining 7a, and further heated at 250 ° C. for 1 hour while being pressurized at 1 MPa to bond the lining 7a to the pressure plate 6a, and the brake pad shown in FIG. 12a. The bonding area between the lining 7a and the pressure plate 6a was 40 cm ² .

[Example 2]
As shown in FIG. 3, the non-porous pressure plate 6b and the lining 7b were bonded in the same manner as in Example 1 described above. The adhesion area between the pressure plate 6b and the lining 7b was made wider than that of the first embodiment by the amount of no holes in the pressure plate 6b.
[Example 3]
As shown in FIGS. 1 and 2, the pressure plate 6a and the lining 7a were bonded in the same manner as in Example 1 described above except that an epoxy-modified phenol resin was used as the adhesive.

[Comparative Example 1]
Irregularities were formed on the adhesive surface of the pressure plate 6a by shot blasting instead of sputter etching as in Example 1. The height of the unevenness was 20 μm Rz. Other than that, the pressure plate 6a and the lining 7a were bonded in the same manner as in Example 1.
[Comparative Example 2]
As shown in FIG. 3, the non-porous pressure plate 6b and the lining 7b were bonded in the same manner as in Comparative Example 1 described above. The adhesion area between the pressure plate 6b and the lining 7b was made wider than that of the comparative example 1 by the amount of no holes in the pressure plate 6b.

  These five types of test pieces were each subjected to a shear test to know the adhesive strength of the joint surface. This shear test is a test method widely known in the field of brake pad manufacturing technology. With the pressure plates 6a and 6b fixed, a force in a direction parallel to the joint surface is applied to the linings 7a and 7b. The measurement was performed by measuring the magnitude of the force that led to the shear fracture of the joint surface and observing the occurrence of the shear fracture. The results of such a shear test are shown in Table 1 below. In Table 1, that the base material fracture area is 100% indicates that shear fracture occurred only in the linings 7a and 7b. On the other hand, the base material fracture areas of 85%, 90%, and 55% indicate that the peeling at the joint surface was 15%, 10%, and 45%. Further, the fact that the thickness is large indicates that the linings 7a and 7b having a relatively large thickness remained on the pressure plates 6a and 6b after the shear fracture. On the other hand, that the thickness is small indicates that the thickness dimensions of the linings 7a and 7b remaining on the pressure plates 6a and 6b after the shear fracture were extremely thin.

  As is apparent from the description of Table 1 showing the results of the test as described above, according to the brake lining bonding method of the present invention, the pressure is higher than that of the conventional method described in Patent Document 3 described above. The adhesive strength between the plates 6a and 6b and the linings 7a and 7b can be improved. In particular, since the adhesive strength at a high temperature (300 ° C.) can be greatly improved as compared with the conventional method, it is advantageous from the viewpoint of ensuring reliability and durability at the time of temperature rise accompanying use of a brake.

  Although the above description has been given of the case where the present invention is applied to a brake pad for a disc brake, the manufacturing method of the present invention can also be implemented for a brake shoe for a drum brake.

DESCRIPTION OF SYMBOLS 1 Support 2 Inner pad 3 Outer pad 4 Caliper 5 Rotor 6, 6a, 6b Pressure plate 7, 7a, 7b Lining 8 Shilling part 9 Piston 10 Locking hole 11 Locking convex part 12a, 12b Brake pad

Claims (2)

  A brake lining bonding method for adhering and fixing a lining that frictionally engages with a braking rotator during braking to a reinforcing plate, and after cleaning the reinforcing plate, at least the lining of the reinforcing plate After forming a large number of fine conical protrusions on the bonding surface, which is the surface to be bonded, by sputter etching, after applying a phosphate treatment to the bonding surface, the adhesive is applied to the bonding surface. A method for bonding a brake lining, characterized in that the lining is bonded and fixed while being heated and pressurized.   The adhesion of a brake lining according to claim 1, wherein the fine conical protrusions each having a diameter of 1.0 µm or less and a height of 0.5 to 1.0 µm are densely formed on the adhesion surface. Method.

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