JPH0552378U - Heat resistant structure of disc brake device in automobiles - Google Patents

Abstract

(57) [Abstract] [Purpose] It is possible to prevent the temperature rise generated by the friction between the pad of the disc brake device and the disc plate from being transmitted to the brake oil side, and the braking condition is guaranteed to prevent collisions. Provided is a heat-resistant structure for a disc brake device in an automobile or the like, which can prevent the occurrence of a car accident and can radiate the increased temperature to the outside to prevent the pad from fading. To do. [Structure] A disk plate 2 provided inside a wheel on which a wheel is mounted is tightened with a pad 5 pushed by a hydraulic piston via a plurality of shims 3 and 4 so as to prevent the wheel from rotating. In the disc brake device 1 of an automobile or the like, a heat insulating density of 1.0 to 2.23 is provided between the shim 3 pushed by the hydraulic piston and the shim 4 attached to the back plate of the pad 5 described above.
The compression-expanded graphite sheet 6 is intervened.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a heat resistant structure of a disc brake device in an automobile or the like.

[0002]

[Prior Art]

 Generally, in a disc brake device of an automobile or the like, the rotation of the wheel is stopped by tightening a disc plate provided inside the wheel to which the wheel is attached with a pad pushed by a hydraulic piston through a plurality of shims. It was done like this. Further, the above-mentioned pad is formed as an integrated product of an iron plate back plate and a friction material.

[0003]

[Problems to be solved by the device]

 However, when an automobile or the like is traveling at a high speed, when the brake pedal is depressed to apply the brake, the friction between the pad of the brake device and the disc plate becomes severe, and the temperature of this portion becomes high.

This temperature can reach 800 ° C. or higher in some cases. Due to this high temperature, the friction coefficient of the pad is reduced (fade), and the braking effect becomes weak. Further, since the shim to which the pad is attached is conventionally made of a vibration-damping steel plate, it has a structure that easily conducts heat. For this reason, bubbles due to high temperature, that is, vapor lock phenomenon may occur in the shim and the hydraulic brake oil for pushing the hydraulic piston. As a result, the pressure generated in the master cylinder is not satisfactorily transmitted, and there is a problem in that the brake feels poor.

As described above, if the braking force becomes poor, a car accident such as a collision may occur, which is very dangerous. An object of this invention is to solve the above conventional problems. That is, it is possible to prevent the temperature rise caused by the friction between the pad of the disc brake device and the disc plate from being transmitted to the brake oil side, the braking condition is guaranteed, and the occurrence of a car accident such as a collision is prevented. (EN) It is possible to provide a heat resistant structure for a disc brake device in an automobile or the like, which is capable of radiating the increased temperature to the outside and suppressing the pad from fading.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the invention is to fix the wheel of an automobile by tightening a disc plate provided inside the wheel on which the wheel is attached with a pad pushed by a hydraulic piston through a plurality of shims. In a disc brake device of an automobile, etc., which is designed to stop rotation, a compression-expansion graphite sheet of density 1.0 to 2.23 for heat release is interposed between the shim pushed by the hydraulic piston and the shim to which the pad is attached. I was supposed to. Further, at least one end of the compression-expanded graphite sheet is projected outward from the back plate of the pad.

[0007]

[Action]

 The compression-expanded graphite sheet with a density of 1.0 to 2.23 interposed between the shim pressed by hydraulic pressure and the shim to which the pad is attached transfers heat in the area direction but does not transfer heat in the thickness direction. Has thermal insulation. As a result, the temperature increased due to the friction between the pad and the disk plate when the brake is applied is insulated by the compression-expanded graphite sheet having the density of 1.0 to 2.23 and is not transmitted to the shim on the hydraulic side. Therefore, no bubbles are generated in the hydraulic brake oil, and it is possible to prevent the occurrence of a vapor lock, that is, the problem that the braking of the brake is deteriorated. This prevents a car accident such as a collision from occurring. Further, since the compressed and expanded graphite sheet having a density of 1.0 to 2.23 transfers heat in the area direction, the increased temperature is radiated outward. Therefore, the pad is prevented from fading. Furthermore, in the case where at least one end of a compressed and expanded graphite sheet with a density of 1.0 to 2.23 projects outward from the back plate of the pad without hindering sliding of the pad, the temperature risen from this protruding portion is outward. It is possible to easily radiate heat to the pads, effectively exhibit the heat dissipation properties, and further prevent the pads from fading.

[0008]

【Example】

 An embodiment of a heat-resistant structure of a brake device in an automobile or the like according to the present invention will be described below with reference to the drawings. 1 is a cross-sectional view showing an embodiment of a heat-resistant structure of a brake device for an automobile or the like according to the present invention, and FIG. 2 is an exploded perspective view showing an overall structure of a brake device for an automobile having a heat-resistant structure according to the present invention, FIG. 3 is a perspective view showing a state in which the brake device of FIG. 2 is being assembled.

A brake device 1 in an automobile or the like is configured such that a disc plate 2 provided inside a wheel (not shown) to which wheels (not shown) are attached is hydraulically pressed through a plurality of shims 3 and 4. The above-mentioned rotation of the wheel is stopped by tightening with the pad 5 to be rotated. The heat-resistant structure of the brake device 1 in an automobile or the like according to the present invention has a specific density for heat insulation, that is, a density of 1.0 to 2.23 between the shim 3 pressed by hydraulic pressure and the shim 4 to which the pad 5 is attached. The adjusted, expanded graphite sheet 6 is interposed.

The reason why the expansive graphite sheet used in this invention is a compressed expansive graphite sheet having a specific density, that is, a density of 1.0 to 2.23 is based on the experimental knowledge of the inventors. This is because it was found that the compressed and expanded graphite sheet adjusted to 1.0 to 2.23 has anisotropy in heat conduction. That is, the compression-expanded graphite sheet adjusted to have a density of 1.0 to 2.23 has a thermal conductivity in the plane direction of about the same as that of metallic copper, but is almost insulative in the thickness direction. Is. Further, as shown in FIG. 1, the end portions 61 and 62 of the compressed and expanded graphite sheet 6 having the density of 1.0 to 2.23 are projected outward from the end portions 31, 32 and 41 and 42 of the shims 3 and 4 on both sides. There is.

In FIG. 2, reference numeral 7 denotes a pad arranged across the disc plate 2 as shown in FIG. 3, the above-mentioned shims 3 and 4 and the pad 5, and shims 3A and 4A and pads provided at the opposite positions. 5A is a mounting support, reference numeral 8 is a guide plate, reference numeral 9 is a piston (not shown) which is operated by brake oil for applying hydraulic pressure to press the shims 3 and 4 and the pad 5 onto the disc plate 2. Is a brake caliper that is mounted so as to cover the mounting support 6. The compression-expanded graphite sheet 6 having a density of 1.0 to 2.23 has a density of 1.0 to 2.23 as described above, and a density of 1.4 to 1.5 is preferable for manufacturing and use.

Hereinafter, the operation of the heat resistant structure of the brake device 1 in an automobile or the like according to the present invention will be described. The compression-expanded graphite sheet 6 interposed between the shim 3 pushed by the hydraulic piston in the direction indicated by the arrow A in FIG. 1 and the shim 4 attached to the back plate of the pad transfers heat in the area direction but is thick. It has adiabatic properties without heat transfer in the depth direction. As a result, the temperature increased by the friction between the pad 5 and the disc plate 2 when the brake is applied is insulated by the compression-expanded graphite sheet 6 and is not transmitted to the shim 3 on the hydraulic piston side. Therefore, no bubbles are generated in the hydraulic brake oil, and it is possible to prevent the occurrence of a vapor lock, that is, the problem that the braking of the brake is deteriorated. This prevents a car accident such as a collision from occurring.

Further, as described above, the compression-expanded graphite sheet 6 transfers heat in the area direction, so that the increased temperature is radiated outward. Therefore, melting of the pad 5 is suppressed. Furthermore, since the end portions 61, 62 of the compression-expanded graphite sheet 6 project outward from the end portions 31, 32 and 41, 42 of the shims 3, 4 on both sides, this projecting portion (end portions 61, 62) It is possible to more easily radiate the temperature risen from the outside to effectively exhibit the heat dissipation property, and to prevent the pad 5 from melting. In particular, since it is strong against the compression pressure, the flow phenomenon in which the end portions 61 and 62 of the compression-expanded graphite sheet 6 are pushed outwards can be prevented, and the heat insulating material is broken by this flow phenomenon, which in turn causes the pad 5 to fade. The drawbacks of the conventional heat insulating material have been solved by using the expanded graphite sheet 6 of the present invention. Next, description will be given of the results of tests conducted to clarify the operational effects of the heat-resistant structure of the brake device 1 in the automobile and the like according to the present invention.

Test Examples (Examples and Comparative Examples) Test Date This test was conducted from 10 am to 3 pm in the middle of July 1991. The weather was fine and the temperature was above 30 ° C. Materials used The brake oil used was Miyako DOT-4 (manufactured by Miyako Motor Co., Ltd.), and the model used was Silvia S-13 model (manufactured by Nissan Motor Co., Ltd.). For the brake pad, a thickness of 10 mm and a project μ3000 (manufactured by project μ company) were used.

Test Method As a test method, a shim in which a compression-expanded graphite sheet having a size of 52 × 92 × 0.5 mm and a density of 2.0 is hydraulically pressed and a shim in which a pad is attached are provided only on the left side of the front of the vehicle. The temperature difference between the left and right brake fluids was measured by performing full braking at a speed of 100 km / h after the pad was sufficiently warmed. The temperature was measured by setting sensors on the mouthpieces of the caliper and brake hose so that the temperature can be measured immediately without removing the wheels. The experimental results showed that the display range of the sensor was 135 ° C to 160 ° C at ambient temperature, but the pad on the right side of the comparative example melted before the temperature of the pasted part rose to this temperature. The experiment was stopped at that point. Therefore, temperature measurement was impossible.

Next, the formation of bubbles in the brake fluid was checked. As for the air bubbles of the brake fluid on the example side with the left-sided compressed and expanded graphite sheet interposed, only one with a length of about 10 mm was generated in the hose, whereas the compressed and expanded graphite sheet with a density of 1.0 to 2.23 was used. Regarding the air bubbles on the side of the comparative example in which the sheet was not inserted, in addition to the large air bubbles having a length of about 150 mm, some small air bubbles were generated. In addition, the compression-expanded graphite sheet itself of the example did not significantly change, and no change was felt in the pedal touch. From the above experimental results, it has been proved that the air bubbles are less likely to be generated in the brake oil by interposing the compression-expansion graphite sheet between the shim pushed by the hydraulic piston and the shim attached to the pad back plate. The heat-resistant structure of the disc brake device according to the present invention is not limited to the disc brake device of an automobile, but can be applied to a disc brake device of a motorcycle, for example.

[0017]

[Effect of the device]

 As described above, according to the present invention, the wheel is attached to the wheel of an automobile or the like by tightening the disc plate provided inside the wheel with a pad pushed by a hydraulic piston through a plurality of shims. In a disc brake device for automobiles, etc., that suppresses the rotation of the above, the compression expansion of density 1.0 to 2.23 for heat insulation is provided between the shim pushed by the hydraulic piston and the shim to which the pad back plate is attached. Since the graphite sheet is interposed, the following effects are achieved. That is, the compression-expanded graphite sheet with a density of 1.0 to 2.23, which is interposed between the shim pushed by the hydraulic piston and the shim to which the pad is attached, transfers heat in the area direction but does not transfer heat in the thickness direction. Since it is hard to be performed and has a heat insulating property, it is possible to prevent the temperature rise caused by the friction between the brake device pad and the disc plate from being transmitted to the brake oil side. Moreover, it is possible to radiate the increased temperature to the outside and prevent the pad from fading.

Furthermore, since at least one end of the compression-expanded graphite sheet is projected outward from the back plate of the pad, the temperature risen from this projected portion is easily released to the outside, and the heat dissipation is improved. It can be effectively exerted to further prevent the pad from melting. As a result, the operation of the brake is always guaranteed and the occurrence of automobile accidents such as collisions can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a heat-resistant structure of a brake device in an automobile or the like according to the present invention.

FIG. 2 is an exploded perspective view showing the entire structure of a vehicle brake device equipped with a heat-resistant structure according to the present invention.

FIG. 3 is a perspective view showing a state in the process of assembling the brake device of FIG.

[Explanation of symbols]

 1 Brake Device 2 Disc Plate 3,4 Shim 31, 32, 41, 42 End 5 Pad 6 Compression Expansion Graphite Sheet 61, 62 End

Claims (2)

[Scope of utility model registration request] 1. The rotation of a wheel of an automobile or the like is stopped by tightening a disc plate provided inside the wheel to which the wheel is attached with a pad pushed by a hydraulic piston through a plurality of shims. In a disc brake device for automobiles, etc., the density of heat insulation is 1.0
A heat-resistant structure for a disc brake device in an automobile or the like, characterized in that a compression-expanded graphite sheet of 2.23 is interposed. 2. The compression-expanded graphite sheet having a density of 1.0 to 2.23 has at least one end protruding outward from an end of a back plate of the pad without hindering sliding of the pad. A heat-resistant structure for a disc brake device in an automobile or the like described.