JPH109299A - Sintered friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the filling a brake heat generated by a friction with a rotary body in a friction material main body by equipping a radiation layer formed by the thermal spray of a metal with higher heat conductivity than that of iron on the side surface of the friction material main body. SOLUTION: A sintered friction material 1 is equipped on both side of a disc rotor respectively so as to hold the disc rotor rotated integrally with the wheel of a vehicle and so that the surface 3a of the friction main body 3 is faced to the rotor. A radiation layer 7 formed by a thermal spray of a metal with higher heat conductivity than the friction material main body 3 is equipped on the side surface of the friction material main body 3. The sintered friction material 1 becomes in such state that the disc rotor is held by the surface 3a of the friction material main body 3 by that the outer surface of a back plate 5 is push-pressed by an oil pressure piston equipped in a caliper and a prescribed brake force is generated. Meantime, the heat radiation effect from the side surface of the main body 3 to the open air is increased extremely due to the radiation layer 7 equipped on the side surface of the friction material main body 3 and the filling of a brake heat in the friction material main body 3 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintered friction material used as a pad for a disc brake of an automobile, for example.

[0002]

2. Description of the Related Art As a pad for a disc brake of an automobile or the like, a friction material body obtained by sintering a friction material material obtained by mixing various powdery components into a thick plate-like predetermined shape, A structure having a metal back plate fixedly mounted on the back side has been developed. Here, the constituent components of the friction material raw material are a binder made of metal powder such as copper, iron, or an alloy thereof, and further various additives such as a friction adjusting material, a grinding material, a lubricant, and the like. The mixing ratio of the constituent components is adjusted according to the physical performance and the like required for the pad.

A disk brake pad (hereinafter, may be simply referred to as a “pad”) having the above-mentioned structure is usually provided with a friction material main body so as to sandwich a disk rotor which is a rotating body that rotates integrally with a vehicle wheel. It is equipped on each side of the disk rotor, with the surface facing the disk rotor. A pair of pads provided on both sides of the disk rotor are supported by calipers, and at least one pad is pressed against the outer surface of the back plate by a hydraulic piston or the like provided in the calipers as pad driving means, It can be moved to the disk rotor side. When the pad is pushed to the disk rotor side by a predetermined distance or more by the pressing by the pad driving means, the disk rotor is sandwiched between the surfaces of the friction material main body of the pair of pads, and a predetermined braking force is generated. .

At the time of braking, frictional heat (hereinafter, referred to as friction) is caused by friction caused by contact between the surface of the disk rotor and the surface of the friction material main body.
(Sometimes referred to as braking heat). A part of this braking heat is transmitted to the hydraulic piston pressing the back plate via the back plate, and further transmitted from the hydraulic piston to brake oil for driving the hydraulic piston. It is not preferable that the temperature of the brake oil rises due to the heat transfer of the braking heat in order to maintain the braking performance.

Therefore, Japanese Patent Laid-Open Publication No. 5-71812 and the like have proposed that a ceramic layer is provided on the outer surface of a back plate pressed by a piston to insulate the piston and brake oil. Also, Japanese Patent Application Laid-Open No. 5-44
No. 591 proposes a technique in which a friction material main body is divided into a plurality of columnar blocks so that the friction material main body itself has air permeability.

[0006]

However, as described above, the structure in which the ceramic layer for heat insulation is provided on the outer surface of the back plate exhibits an excellent effect for heat insulation on the piston side.
When the brake operation is performed continuously, the braking heat is trapped in the friction material main body and the temperature of the friction material main body itself rises sharply. As a result, the surface temperatures of the friction material main body and the disk rotor that rub against each other are reduced. As a result, the friction coefficient between the surfaces to be rubbed is sharply reduced, and the braking performance may be significantly reduced.

On the other hand, in a configuration in which the friction material main body is divided into a plurality of cylindrical blocks so that the friction material main body itself has air permeability, accumulation of braking heat in the friction material main body can be reduced. At the same time as reducing the heat transfer to the piston side, it is also possible to suppress the rise in the surface temperature of the friction material body and the disk rotor that rub against each other, but it takes a lot of labor to form the friction material body, There was a problem that the cost was increased.

The present invention has been made in view of the above circumstances, and the braking heat generated by the friction with the rotating body is trapped in the friction material main body by enhancing the heat radiation effect from the side surface of the friction material main body to the outside air. Therefore, even in the case where the brake operation is performed continuously, the temperature of the surface of the friction material body that rubs against the rotating body is suppressed, and at the same time, the driving means side that presses the friction material body against the rotating body. To provide a sintered friction material capable of suppressing heat transfer to the sintered friction material. Further, it is an object of the present invention to be able to maintain excellent braking performance, to save time and effort in manufacturing, and to reduce manufacturing costs.

[0009]

In order to achieve the above object, a sintered friction material according to the present invention has a constitution in which a friction material raw material obtained by mixing various powdery components is formed into a predetermined thick plate shape. The friction material body comprises a sintered friction material body, and a metal back plate fixedly mounted on the back surface side of the friction material body. In a sintered friction material that generates a braking force by pressing a surface of a material body against a surface of a rotating body, a heat radiation formed by spraying a metal having higher thermal conductivity than iron on a side surface of the friction material body. It is characterized by having a layer.

[0010] In the sintered friction material according to the present invention, in the above structure, the heat radiation layer is further formed by thermal spraying of an Al-Zn pseudo alloy in which aluminum and zinc are mixed. It is.

In the above structure, the heat radiation layer provided on the side surface of the friction material main body significantly enhances the heat radiation effect from the side surface of the friction material main body to the outside air, and as a result, it is generated by friction with the rotating body. It is possible to prevent the generated braking heat from being trapped in the friction material main body. Therefore, even when the brake operation is performed continuously, the temperature rise on the surface of the friction material body that rubs against the rotating body is suppressed, and at the same time, the heat transfer to the drive unit that presses the friction material body against the rotating body is suppressed. And excellent braking performance can be maintained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a sintered friction material according to the present invention will be described below in detail with reference to the drawings. 1 and 2 show one embodiment of a sintered friction material according to the present invention. FIG. 1 is a perspective view of a sintered friction material of one embodiment,
FIG. 2 is a sectional view taken along line AA of FIG.

The sintered friction material 1 of this embodiment is used as a pad for a disc brake of an automobile.
A friction material body 3 obtained by sintering a friction material material obtained by mixing various powdery constituent components into a thick plate-like predetermined shape, and a metal back plate fixedly mounted on the back side of the friction material body 3 5 is provided. Here, the constituent components of the friction material raw material are a binder made of metal powder such as copper, iron, or an alloy thereof, and further various additives such as a friction adjusting material, a grinding material, a lubricant, and the like. The mixing ratio of the constituent components is adjusted according to the physical performance and the like required for the pad.

A heat radiation layer 7 formed by spraying a metal having higher thermal conductivity than the friction material main body 3 is provided on the side surface of the friction material main body 3. The heat radiation layer 7 is formed by mixing (not chemically bonding) aluminum and zinc.
It is formed by thermal spraying of l-Zn pseudo alloy.
In the present embodiment, the thickness of the heat radiation layer 7 is 50 to 100.
It is in the range of μm.

Further, in the case of the sintered friction material 1 of this embodiment, a ceramic layer 9 for heat insulation is provided on the outer surface of the back plate 5.

Although not shown, the above-mentioned sintered friction material 1 has a surface 3 of the friction material main body 3 so as to sandwich a disk rotor which is a disk-shaped rotating body that rotates integrally with a vehicle wheel.
A is provided on each side of the disk rotor, with a facing the disk rotor. A pair of sintered friction materials 1 provided on both sides of the disk rotor are supported by calipers, and at least one of the sintered friction materials 1 is provided with a back plate 5 by a hydraulic piston or the like provided in the calipers as pad driving means. When the outer surface is pressed, it can be moved to the disk rotor side. When the sintered friction material 1 is pushed to the disk rotor side by a predetermined distance or more by the pressing by the pad driving means, the disk rotor is sandwiched by the surfaces 3a of the friction material main body 3 of the pair of sintered friction materials 1. Thus, a predetermined braking force is generated.

In the sintered friction material 1 described above, the heat radiation effect from the side surface of the friction material main body 3 to the outside air is remarkably enhanced due to the heat radiation layer 7 provided on the side surface of the friction material main body 3, and as a result, during braking, It is possible to prevent the braking heat generated by friction with the disk rotor from being trapped in the friction material main body 3.
Therefore, even when the brake operation is performed continuously, the surface 3a of the friction material main body 3 that rubs against the disk rotor.
At the same time, the heat transfer to the drive means for pressing the friction material body 3 against the disk rotor can be suppressed, and excellent braking performance can be maintained.

Actually, in order to confirm the effect of the heat radiation layer 7 provided on the side surface of the friction material main body 3, heating was performed from the surface side of the friction material main body 3, and the temperature rise of the friction material main body 3 was measured. FIG. 3 shows the method of this heating test. In the sintered friction material 1, the surface 3a of the friction material body 3 having the heat radiation layer 7 formed on the side surface is brought into close contact with the heating plate 11, and the contact temperature of the outer surface of the back plate 5 (that is, the surface of the ceramic layer 9) is increased. The heating plate 11 was heated to a predetermined temperature, and the temperature was measured every 15 seconds, thereby observing the temperature change (that is, the heat dissipation in the sintered friction material 1). For comparison, a similar test was performed on the heat radiation layer 7.
This was also carried out on a comparative sintered friction material not equipped with a. The comparative sintered friction material has the same configuration as the sintered friction material 1 except that the heat radiation layer 7 is not provided.

FIG. 4 shows the measurement results when the temperature of the heating plate 11 is 300 ° C., and FIG.
FIG. 6 shows the measurement results when the temperature of the heating plate 11 is 5
The measurement result at the time of 00 ° C. is shown. 4 to 6, the temperature change curve L connecting the + marks is for the comparative sintered friction material, and the temperature change curve M connecting the □ marks is for the sintered friction material 1 of one embodiment. Things. As is clear from these figures, the sintered friction material 1 according to one embodiment can reduce the temperature rise by about 10% as compared with the case where the heat dissipation layer 7 is not provided. Has been confirmed to function effectively.

Further, since the heat radiation layer 7 is formed by so-called thermal spraying and can be formed relatively easily, no trouble is required in the production, and the production cost can be reduced.

The metal forming the heat radiation layer 7 is not limited to the Al-Zn pseudo alloy shown in the above-described embodiment. Various metals other than Al-Zn pseudo alloys can be used as long as they have high thermal conductivity in a high temperature environment during braking.

In the sintered friction material 1 according to the above-described embodiment, the outer surface of the back plate 5 is formed on the outer surface of the back plate 5 for the purpose of suppressing heat transfer to the pad driving means that presses the sintered friction material 1 toward the disk rotor. Although the ceramic layer 9 is provided, the temperature rise of the friction material main body 3 is suppressed to within an allowable range (a range where the braking performance is not reduced) by the provision of the heat radiation layer 7, and the heat transfer to the pad driving means side is further reduced. If it is within the acceptable range,
The ceramic layer 9 may be omitted.

The sintered friction material according to the present invention can be used not only for disc brakes of automobiles but also for disc brake devices mounted on various industrial machines.

[0024]

According to the sintered friction material of the present invention, the heat radiation layer provided on the side surface of the friction material body greatly enhances the heat radiation effect from the side surface of the friction material body to the outside air. It is possible to prevent braking heat generated by friction with the body from being trapped in the friction material main body. Therefore, even when the brake operation is performed continuously, the temperature rise on the surface of the friction material body that rubs against the rotating body is suppressed, and at the same time, the heat transfer to the drive unit that presses the friction material body against the rotating body is suppressed. And excellent braking performance can be maintained. And actually, in order to confirm the effect of the heat radiation layer provided on the side surface of the friction material main body, heating was performed from the surface side of the friction material main body, and the temperature rise of the friction material main body was measured. It was confirmed that the temperature rise could be reduced by about 10% as compared with the case without the above, and it was confirmed that the heat radiation layer was functioning effectively. Also, the heat dissipation layer
Since it is formed by so-called thermal spraying and can be formed relatively easily, no trouble is required in manufacturing, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a sintered friction material according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory diagram of a measurement method for confirming the operation and effect of the sintered friction material according to one embodiment of the present invention.

FIG. 4 is a first temperature characteristic diagram showing the operation and effect of the sintered friction material of one embodiment of the present invention.

FIG. 5 is a second temperature characteristic diagram showing the operation and effect of the sintered friction material according to one embodiment of the present invention.

FIG. 6 is a third temperature characteristic diagram showing the operation and effect of the sintered friction material according to one embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 sintered friction material 3 friction material main body 5 back plate 7 heat radiation layer

Claims (2)

[Claims] 1. A friction material main body obtained by sintering a friction material raw material obtained by mixing various powdery constituents into a thick plate-like predetermined shape, and a metal material fixedly mounted on the back side of the friction material main body. A sintered friction material that generates a braking force by pressing the outer surface of the back plate with a predetermined driving means to press the surface of the friction material main body against the surface of the rotating body. The sintered friction material 1 according to claim 1, further comprising a heat radiation layer formed by spraying a metal having a higher thermal conductivity than iron on a side surface of the friction material main body. 2. The sintered friction material according to claim 1, wherein the heat radiation layer is formed by thermal spraying of an Al—Zn pseudo alloy in which aluminum and zinc are mixed.