JPH08326797A - Squeal preventing shim - Google Patents

Abstract

PURPOSE: To provide a squeal preventing shim for disk brake which can reduce high frequency noise (a squeal phenomenon) generated at braking. CONSTITUTION: A rubber coat metal formed by providing a rubber layer 2 on one face of a metal plate is used, a pressure sensitive adhesive layer 3 is provided directly or through a primer layer P on the face with no rubber layer of the metal plate 1 so as to form a shim structure B, and the pressure sensitive adhesive layer 3 of the shim structure B is used for the adhering part to the back plate 4 of a pad for disk brake. Because the pressure sensitive adhesive layer 3 is provided on the metal plate 1 in this way, the pressure sensitive adhesive layer is not peeled from the rubber coat metal, and hence damping action (squeal preventing action) is maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeal prevention shim for a disc brake of an automobile, and more particularly to an improvement of a vibration suppression shim for reducing high frequency noise (squeaking phenomenon) generated during braking of a brake.

[0002]

2. Description of the Related Art Conventionally, as a squeal prevention shim for an automobile disc brake, as shown in FIG. 8, a thin metal plate 1 such as an iron plate (cold rolled steel plate), a stainless steel plate or a copper plate is coated with a thin rubber by rubber coating. A rubber coat metal (RCM) having layers 2 and 2 is used as a material, and an adhesive layer 3 is provided on the surface of one rubber layer of the material to form a shim structure A. The shim structure A is shown in FIG. As shown, the back plate 4 of the disc pad consisting of the back plate 4 and the friction material 5 is adhered to the back plate 4 by the surface of the pressure-sensitive adhesive layer 3, and the RCM-pressure-sensitive adhesive layer 3-back plate 4 forms a restrained damping structure. Then, shear deformation is caused between the back plate 4 and the RCM, and a vibration damping action (squeal prevention action) is obtained by this shear deformation. In addition, 6 is a brake piston member.

[0003]

In the shim structure, the antiaging agent contained in the rubber layer 2 due to the heat generated by friction and the pressing force received from the piston member when the disc brake is operated. The ozone deterioration inhibitor deposits and moves on the surface of the rubber layer (called a blooming phenomenon) to form a deposit layer at the interface between the rubber layer 2 and the adhesive layer 3. The anti-aging agent or ozone deterioration inhibitor (wax content) that has moved to the rubber layer / adhesive interface in this way is 60
Since it melts at ℃ to 75 ℃, peeling of the RCM and the adhesive layer occurs. In this state, the pressure-sensitive adhesive layer is not constrained between the back plate and RCM, so that the vibration damping action (squealing prevention action) is reduced without causing shear deformation.

The present invention has been made in order to solve the drawbacks of the shim structure in which the pressure-sensitive adhesive layer is provided on the conventional rubber-coated metal, and it is a precipitation that reduces the strength of the interface between the RCM and the pressure-sensitive adhesive layer. The main object of the present invention is to provide a squeal prevention shim for disc brakes in which the vibration damping action (squeal prevention action) is maintained without the movement of objects and the peeling between the RCM and the adhesive layer.

[0005]

A first invention of the present application uses a rubber-coated metal having a rubber layer provided on only one side of a metal plate, and an adhesive layer is provided on the opposite side of the metal plate to form a shim structure. The gist is that it is formed as a body and the adhesive layer of the shim structure is used as an adhesive portion of the disc brake pad. When the pressure-sensitive adhesive layer is provided on the metal plate, there is a method of directly coating the pressure-sensitive adhesive layer on the metal plate, and also a method of coating the pressure-sensitive adhesive on the surface of the metal plate after the primer layer is provided. The adhesiveness between the metal plate and the pressure-sensitive adhesive can be further enhanced, and can be appropriately selected according to the required performance level. Examples of the primer layer include phenol resins, but epoxy resins, acrylic resins, coupling agents and the like can be widely used. According to the shim structure having the above structure, the adhesive layer is directly provided on the metal plate surface forming the rubber-coated metal and is adhered to the back plate, whereby the rubber-coated metal and the adhesive layer are separated from each other. And the damping effect (squealing prevention effect) is maintained.

Further, a second invention of the present application is characterized in that, in the structure of the first invention, a low friction material layer is provided on the surface of the rubber layer to form a shim structure. Examples of the low friction material layer include graphite and molybdenum disulfide grease. According to the shim structure of the second invention, the low-friction material layer provided on the surface of the rubber layer reduces friction with the brake piston member and blocks vibrations that cause "brake squeal". Has the effect of

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As a first invention of the present application, a rubber-coated metal having a rubber layer 2 provided on one surface of a metal plate 1 is used, and a primer layer P is provided on the surface of the metal plate 1 without the rubber layer. The pressure sensitive adhesive layer 3 is provided to form a shim structure B, and the pressure sensitive adhesive layer 3 of the shim structure B serves as an adhesive portion of the disc pad including the back plate 4 and the friction material 5 to the back plate 4.

[0008]

1 and 2 show an embodiment of the first invention. The members that are the same as or similar to those in FIGS.
The same reference numerals are attached. In FIG. 1, B is a shim structure, 1 is a metal plate, 2 is a rubber layer provided on one side thereof, and the surface of the metal plate 1 without the rubber layer is adhered via a primer layer P. The agent layer 3 is directly provided. Although it is not necessary to limit the thickness of any of the constituent materials, there is a limit to the clearance between the pad and the brake piston member, particularly when it is used as a brake shim, and the following thickness range is generally preferable. The metal plate 1 has a thickness of 0.
It is preferable to use a cold rolled steel plate and a stainless steel plate of 4 mm to 0.6 mm, and the rubber layer 2 has a thickness of 20 to 200 μm.
The thickness of the pressure-sensitive adhesive layer 3 is preferably in the range of 50 to 200 μm.

FIG. 2 shows the shim structure B adhered to the back plate 4 of the disk pad. According to the configuration of the shim structure B, since the pressure-sensitive adhesive layer 3 is directly bonded to the metal plate 1 via the primer layer P, a rubber layer that lowers the strength of the pressure-sensitive adhesive layer interface like a conventional product. There is no elution of precipitates from the above, and therefore the rubber-coated metal and the pressure-sensitive adhesive layer are not separated from each other, and the vibration damping action (squealing prevention action) is maintained.

FIG. 5 shows the conventional shim structure A shown in FIG.
2 is a graph comparing the number of squeals when the shim structure B according to the present invention shown in FIG. 1 is used as a sample and both samples are subjected to a squeal dynamo test. This test was performed with an experimental device that evaluates the "squeal" that occurs when the tires that are actually rotating are stopped by the disc brakes. Evaluation is 10
It is generally said that the brakes squeal three times up to 00 times, but in this test, 270 brake shims per cycle were repeated for 10 cycles (2700 total braking times). Shim structure A
The squeal of No. 2 was 60/2700 times, whereas the squeaking of the shim structure B of the present invention was 3/2700 times.

FIG. 6 is a graph showing the relationship between the adhesive length of the pressure-sensitive adhesive layer and the vibration damping property by the beam test.
(60/240), (120/240), (180/2
40) shows (bonded portion length / total length). FIG. 7 shows the configuration of the beam test apparatus. B is a shim structure made of rubber-coated metal (length 240 mm, width 15 mm), 3 is an adhesive layer, and 7 is thickness 3.
The beam is 0 mm wide and 15 mm wide. If the cause of the squeaking is the bending vibration mode of the brake pad (back plate), replacing the beam 7 with the back plate makes the squeal prevention equal to the beam test damping capability.

As shown in the graph of the beam test of FIG. 6, it was confirmed that the wider the length of the bonded portion by the pressure-sensitive adhesive layer, the higher the vibration damping property. In this beam test, peeling of the pressure-sensitive adhesive layer was reproduced as a model, and its damping ability was measured. It can be said that the smaller the length of the bonded portion, the larger the peeling. In other words, it shows that the product of the present invention that can obtain a good adhesion state can obtain a higher squeal prevention result even if all the materials are the same as those of the conventional product. Incidentally, it can be seen from FIGS. 5 and 6 that the single rubber layer in the conventional product is not an effective existence.

3 to 4 show an embodiment of the second invention. The same or similar members as in FIGS.
The same reference numerals are attached. In FIGS. 3 to 4, B ′ is a shim structure, 1 is a metal plate, 2 is a rubber layer provided on one side of the shim structure via a primer layer P ′, and 3 is a rubber layer of the metal plate 1. A low-friction material layer 8 such as graphite or molybdenum disulfide grease is provided on the surface of the rubber layer 2, which is a pressure-sensitive adhesive layer adhered to the surface via a primer layer P. Reference numeral 4 is a back plate, 5 is a friction material, and 6 is a brake piston member.

In the above structure, since the low friction material layer 8 is provided on the surface of the rubber layer 2, the friction between the low friction material layer 8 and the piston member 6 is reduced, and the vibration causing the "brake squeal" is blocked. The effect is obtained. For example, in the case where graphite is applied as the low friction material layer 8, the static friction coefficient for a clean and smooth mating metal surface is reduced by 30 to 50% compared to the case where graphite is not applied, and a squeal dynamo test is performed. Then, it was confirmed that the number of squealing was reduced by 5 to 10%.

[0015]

As described above in detail, according to the first invention of the present application, a rubber-coated metal having a rubber layer provided on only one surface of the metal plate is used, and the rubber-coated metal is opposite to the metal plate. Since the shim structure is formed by providing the pressure-sensitive adhesive layer on the surface, it is possible to obtain the anti-squeal shim for disc brakes in which the vibration damping effect (squeal prevention effect) is maintained for a long period of time. In addition, according to the second aspect of the invention, since the low friction material layer is provided on the surface of the rubber layer that is in contact with the brake piston member of the shim structure, vibrations that cause "brake squeal" are blocked, It is possible to obtain a squeal prevention shim for a disc brake, which can reduce the number of squeal by the vibration blocking action.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a squeal prevention shim for a disc brake showing an embodiment of the first invention.

FIG. 2 is a cross-sectional view showing a state in which the shim is bonded to a disc brake pad.

FIG. 3 is a sectional view of a squeal preventing shim for a disc brake showing an embodiment of the second invention.

FIG. 4 is a cross-sectional view showing a state in which the shim is bonded to a disc brake pad.

FIG. 5 is a graph showing the number of squeals in a squeal dynamo test of a shim structure.

FIG. 6 is a graph showing the relationship between the length of the adhesive portion of the pressure-sensitive adhesive layer and the vibration damping property measured by the beam test.

FIG. 7 is a schematic diagram of a beam test apparatus.

FIG. 8 is a cross-sectional view of a conventional anti-squeal shim for disc brakes.

FIG. 9 is a cross-sectional view showing a state in which the shim is bonded to a disc brake pad.

[Explanation of symbols]

 A Conventional Shim Structure 1 Metal Plate 2 Rubber Layer 3 Adhesive Layer P, P'Primer Layer 4 Back Plate 5 Friction Material 6 Brake Piston Member B, B'Shim Structure of the Present Invention 7 Beam of Beam Tester 8 Low Friction material layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masataka Yoshihara 7-4-40 Tatsuta Ikaruga Town, Ikoma District, Nara Prefecture Tatsuda Dormitory No. 401

Claims (4)

[Claims] 1. A shim structure is formed by using a rubber-coated metal having a rubber layer provided on only one side of a metal plate, and forming a shim structure by providing an adhesive layer on the surface of the metal plate without the rubber layer. A squeal prevention shim for disc brakes, wherein the adhesive layer is used as an adhesive portion to the disc brake pad. 2. The squeal for a disc brake according to claim 1, wherein a rubber layer is provided on the metal plate via a primer layer, and an adhesive layer is provided on a surface of the metal plate having no rubber layer via the primer layer. Prevent shim. 3. A rubber-coated metal having a rubber layer provided on only one side of a metal plate, an adhesive layer is provided on the side of the metal plate having no rubber layer, and a low-friction material layer is provided on the surface of the rubber layer. A squeal prevention shim for a disc brake, which is provided as a shim structure, and an adhesive layer of the shim structure serves as an adhesive portion to a disc brake pad. 4. The anti-squeal shim for a disc brake according to claim 3, wherein graphite or molybdenum disulfide grease is used for the low friction material layer.