JPS627863Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a friction pad for a disc brake that prevents the occurrence of dragging when the disc brake is not in operation.

A disc brake is a type of brake that suppresses rotation of a rotating disc by pressing a pair of brake pads against friction surfaces formed on both sides of the disc, and is widely used for vehicles.

However, disc brakes have a serious drawback that they tend to cause a so-called dragging phenomenon in which the brake pads contact the friction surface of the disc with a constant force even when not in operation. When this drag occurs, it not only wastes the vehicle's running energy, but also shortens the life of the friction plate and causes brake overheating.

In order to solve the above problems, the present applicant has previously developed and filed an application for a disc brake equipped with a friction pad having a gap generation mechanism between the friction surface of a disc rotor and the friction pad. Special request No. 55-
This is No. 012234.

The disc brake friction pad provided in this disc brake is disposed between the friction surface of the disc rotor and an actuator for pressing the friction pad against the friction surface. a member, a first backing plate fixed to the back side of the member, and a second backing plate overlaid on the first backing plate and transmitting the pressing force of the actuator to the friction member;
the back surface of the first back plate and the second
The front surface of the back plate is a mutually complementary inclined surface, and when a pressing force is applied from the actuator,
When the first back plate is displaced relative to the second back plate in a direction parallel to the plate surface of the disc rotor based on the friction force in the rotational direction of the disc rotor that the friction member receives from the friction surface, The thickness of the entire back plate consisting of the first back plate and the second back plate is substantially increased, and the stopper means for limiting displacement of both the back plates and the pressing force are removed. A spring is provided which acts in a direction substantially parallel to the plate surface of the disk rotor in order to restore the displacement.

However, on the sliding surface between the first back plate and the second back plate, the surface roughness may deteriorate due to rust, lack of oil, harsh use, etc., and the coefficient of friction may increase. For this reason, when the brake is applied, a loud operating sound is generated when the brake pad comes into contact with the stopper.In addition, uneven misalignment between the back plates causes uneven wear on the surface of the pad sliding surface that slides against the disc rotor, resulting in dragging and poor braking sensation. There was a drawback that deterioration occurred. Moreover, the heat generated on the sliding surface between the back plates due to frequent operation may thermally deform the pad sliding surface, resulting in drag.

The present invention was developed against the background of the above-mentioned circumstances, and its purpose is to prevent rust and oil from forming on the sliding surface between the first back plate and the second back plate of the disc brake friction pad. It is an object of the present invention to provide a friction pad for a disc brake that does not cause deterioration of surface roughness or increase of friction coefficient due to insufficient or harsh use.

In order to achieve this object, the present invention is characterized in that at least one of the first back plate and the second back plate of the friction pad for a disc brake is made of sintered metal impregnated with a lubricant. .

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, 1 is a disc rotor, which is provided with friction surfaces 2 and 3 on both sides of the outer periphery,
It rotates around an axis together with wheels (not shown). A torque member 4 is arranged near the disc rotor 1. The torque member 4 includes a flat plate part (not shown) extending parallel to both friction surfaces 2 and 3 of the disc rotor 1, and a connecting part 5 that extends beyond the outer periphery of the disc rotor 1 and connects the two, and includes a knuckle, an axle pipe, etc. is fixed to a non-rotating member. An opening 6 is provided in the center of the torque member 4.
A caliper 7, an inner pad 8, and an outer pad 9 are disposed within this opening 6.

The caliper 7 has protrusions 13 on both sides,
It is supported by a torque member 4 via a spring 14 and a guide member 15 so as to be movable in a direction parallel to the axis of the disc rotor 1 . Both ends of the spring 14 are hooked to the torque member 4, and the central bent portion is in contact with the lower disk rotor axis side surface of the protrusion 13, and the guide member 15 is attached to the protrusion 1.
It is in contact with the top surface of 3. This caliper 7 includes a piston 17 that is an actuator that is slidably fitted to a cylinder 16 and a reaction portion 18 that faces the outer pad. When brake fluid pressure is supplied to the cylinder 16, the piston 17 moves the inner pad 8 to the disc rotor 1. The reaction part 18 is pressed against the friction surface 2 of the outer pad 9 due to this reaction.
is pressed against the friction surface, thereby suppressing the rotation of the disc rotor 1. A piston seal 21 ensures oil tightness between the piston 17 and the cylinder 16, and is elastically deformed when the piston 17 is pushed out, thereby keeping the piston 17 free when the hydraulic pressure is removed. It has the effect of returning to the working position.

As shown in FIGS. 3 to 5, the inner pad 8 includes a plate-shaped friction member 22, a first back plate 23 fixed to the back surface of the friction member 22, and a second back plate 2 superposed thereon.
4, and the first back plate 23 is fitted into a recess 25 provided in the second back plate 24. The contacting surfaces of the first back plate 23 and the second back plate 24, that is, the back surface of the first back plate 23 and the front surface of the second back plate 24, become closer to the disk rotor 1 as they move away from the axis of the disk rotor 1. The inclined surfaces 26 and 27 approach each other, and the portion where the corner of the first back plate 23 on the axis side of the disk rotor 1 and the inner surface of the circumferential frame of the concave portion 25 are in contact with each other is provided with a first surface.
Two pairs of inclined surfaces 30 and 31 and 28 and 29 are provided which are in contact with each other and which are spaced apart from the axis of the disk rotor 1 as the back plate 23 moves in the circumferential direction of the disk rotor 1.

A leaf spring 32 is screwed to the lower part of the first back plate 23, and this leaf spring 32 is disposed in a notch 33 in the peripheral frame of the recessed part 25, and also in a notch 33 on the outside of the peripheral frame. It is engaged in a groove 34 provided nearby to urge the first back plate 23 toward the axis of the disk rotor 1, and also to engage the first back plate 23 and the second back plate 24 with each other. .

A certain gap is ensured between both side ends and the upper end of the first back plate 23 and the circumferential frame of the recessed part 25, and the amount corresponding to this gap is between the first back plate 23 and the second back plate 24. This is the allowable amount of deviation movement. In addition, in order to maintain the coefficient of friction between the opposing inclined surfaces 26 and 27 at a low constant value and to make the displacement movement smooth even under various conditions, the second back plate 24 has lubricity, wear resistance,
It is made of sintered metal impregnated with a lubricant that has excellent corrosion resistance and heat resistance. Therefore,
Since deterioration of surface roughness due to rust, lack of oil, harsh use, etc. does not occur, an increase in the coefficient of friction is prevented. Note that 35 is an oil groove.

An outer pad 9 having a similar structure is arranged symmetrically between the reaction section 18 and the disc rotor 1.

The operation of this embodiment will be explained below.

When hydraulic pressure is supplied into the cylinder 16, this hydraulic pressure is transmitted to the piston 17 and then to the inner pad 8. Then, the inner pad 8 is pushed out toward the disc rotor 1 and the friction member 22 comes into contact with the disc rotor 1. As a result, a frictional force is applied to the friction member 22 in the circumferential direction of the disc rotor.
The friction member 22 and the first back plate 23, which are integrally fixed, are displaced in the circumferential direction against the biasing force of the leaf spring 32. At the same time, a radial force generated based on the inclined surfaces 28, 29 or 30, 31 acts on the first back plate 23, causing it to shift in the radial direction,
The thickness of the entire back plate consisting of the first back plate 23 and the second back plate 24 becomes substantially thicker. In this state, the side ends of the first back plate 23 come into contact with the peripheral frame of the concave portion 25, and further displacement is prevented. During this contact, almost no sound is generated because the initial friction of the disengaged surfaces is small.

When the inner pad 8 comes into contact with the disc rotor 1, the reaction force acts on the reaction 18 of the caliper 7. This reaction force is transmitted to the outer pad 9,
As a result, the outer pad 9 is pushed toward the disk rotor 1 and brought into contact with it. Therefore, the thickness of the entire back plate of the outer pad 9 becomes substantially thicker due to the same effect as that of the inner pad 8 described above, and both pads 8 and 9 with the thicker back plates are able to form a disk rotor. 1 rotation is suppressed.

Then, when the brake fluid pressure is removed, the piston 17 is returned to its inactive position by the action of the piston seal 21. At the same time, the inner pad 8 is released from the pressing force and the frictional force in the rotational direction caused by the disc rotor 1, and the first back plate 23 returns to its original position based on the biasing force of the leaf spring 32, and the thickness of the entire back plate is reduced to its original thickness. Returning to the above, a gap is created between the friction surface 2 and the friction member 22 corresponding to at least the amount of decrease in the thickness of the entire back plate,
Avoid dragging.

Similarly, the action of the reaction force acting on the reaction portion 18 is also canceled, and a gap is created between the friction member of the outer pad 9 and the friction surface 3.

In this way, since the second back plate is made of sintered metal impregnated with lubricant, the first back plate 23 and the second back plate 2
4, there is no increase in the coefficient of friction due to rust, lack of oil, harsh use, etc., and smooth displacement is ensured even under various conditions, so the first back plate 23 occurs when the brake is applied. There is no loud contact noise, uneven wear of the pad slide surface due to uneven displacement of the first back plate 23, and the resulting dragging and deterioration of braking feeling.
This prevents thermal deformation of the pad sliding surface due to heat generation from the sliding surfaces of Nos. 3 and 24 and drag caused by this. Furthermore, since sintered metal has a relatively low thermal conductivity, it is possible to prevent thermal deterioration of brake components with low heat resistance, such as piston seals and brake fluid.

What has been described in detail above is merely one embodiment of the present invention, and it goes without saying that the present invention should not be interpreted as being limited thereto.

For example, since it is sufficient to maintain the coefficient of friction between the first back plate 23 and the second back plate 24 at a low constant value even under various conditions, not only the second back plate 24 but also the first back plate 23 or Both may be made of sintered metal impregnated with a lubricant.

In addition, in the brake friction pad, the first back plate fixed to the friction member and the second back plate stacked on it are different, and the thickness of the entire back plate is reduced due to the displacement of the first back plate based on the frictional force of the disc rotor. Since a thicker one is sufficient, the inclination between the two back plates as described above is not limited to the radial direction of the disc rotor, but may be in the circumferential direction. In this case, the inclined surfaces 28, 29, 30, 31, etc. for moving the first back plate in the radial direction of the disk rotor become unnecessary.

As described in detail above, the present invention provides a first back plate and a second back plate constituting the friction pad of the disc brake.
At least one of the back plate and the back plate is made of sintered metal impregnated with lubricant, which enables smooth displacement between the two under various conditions.
There is no contact noise of the back plate, uneven wear of the pad slide surface due to uneven displacement, and there is no drag or deterioration of braking feeling caused by this, and there is no thermal deformation of the pad slide surface due to heat generated from the sliding surfaces of both back plates. This has the effect of providing a friction pad for a disc brake that does not cause dragging caused by this. Furthermore, by reducing the heat conduction generated in the friction member, it is possible to prevent thermal deterioration of brake components having low heat resistance such as the piston seal and brake fluid.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a disc brake according to an embodiment of the present invention. FIG. 2 is a sectional view taken along the line AA in FIG. 1. FIG. 3 is a front view of essential parts of an embodiment of the present invention. FIG. 4 is a sectional view taken along line BB in FIG. 3. FIG. 5 is a partial explanatory diagram of FIG. 3. 1: Disc rotor, 2, 3: Friction surface, 8,
9: Friction pad, 17: Actuator (piston), 22: Friction member, 23: First back plate, 24:
2nd back plate, 26, 27: inclined surface, 32: (plate) spring.

Claims (1)

[Claims for Utility Model Registration] A friction member disposed between the friction surface of the disc rotor and the actuator and pressed against the friction surface, a first back plate fixed to the back side of the friction member, and the first back plate. a second back plate that is overlapped and transmits the pressing force of the actuator to the friction member, and the back surface of the first back plate and the front surface of the second back plate that is in close contact with the back surface have mutually complementary slopes. a surface, and when a pressing force is applied from the actuator, the first
When the back plate is shifted relative to the second back plate in a direction parallel to the plate surface of the disk rotor, the thickness of the entire back plate consisting of the first back plate and the second back plate is substantially a stopper means for limiting displacement of the back plates; and a spring acting in a direction substantially parallel to the plate surface of the disk rotor to restore the displacement when the pressing force is removed; 1. A friction pad for a disc brake, wherein at least one of the back plates is made of sintered metal impregnated with a lubricant.