JPH0722503Y2 - Caliper for disc brake - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caliper used in a disc brake, and more particularly to a caliper having a resin piston inside a cylinder portion thereof.

2. Description of the Related Art Disc brakes generally have a cylinder portion in which a cylinder bore that opens toward the disc rotor is formed, and a metal caliper that spans the outer peripheral portion of the disc rotor and the cylinder bore of the caliper. It is configured to include a metal piston fitted with a predetermined fitting clearance so as to be capable of projecting, and a pair of pads arranged inside the caliper so as to sandwich the disk rotor, and in the cylinder bore. The disc rotor is narrowed by a pair of pads and braking is performed based on the fact that the piston is projected from the cylinder bore by the supplied hydraulic pressure. During braking of such a disc brake, the cylinder portion is separated from the disc rotor toward the inner peripheral side of the disc rotor, and is separated from the outer peripheral surface of the piston by a predetermined distance in the axial direction and in the radial direction of the disc rotor. In some cases, the two locations located on the opposite sides of each other may be rubbed while being pressed by the inner peripheral surface of the cylinder bore.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in such a disc brake, the piston is made of resin for the purpose of preventing transmission of braking heat from the pad through the piston to the brake fluid in the cylinder bore and reducing the weight. However, as the resin piston protrudes from the cylinder bore of the metal cylinder during braking with high hydraulic pressure, the inner circumference of the cylinder bore causes the outer circumference of the resin piston to If the two points on the surface are strongly pressed and rubbed, the outer peripheral surface of the resin piston may be damaged, or an unreasonable force may be applied to the resin piston in the substantially radial direction of the disc rotor.

The present invention has been made in view of the above circumstances, and its purpose is to provide a resin piston by a metal cylinder portion that is separated from the disk rotor toward the inner peripheral side of the disk rotor during braking. It is an object of the present invention to provide a disc brake caliper that can prevent damage or an unreasonable force acting on the resin piston in the disc rotor radial direction.

Means for Solving the Problems In order to achieve the above object, the present invention has a cylinder portion having a cylinder bore that opens toward a disc rotor, and is provided over the outer peripheral portion of the disc rotor. The piston made of resin slidably fitted in the cylinder is braked based on the protrusion from the cylinder bore, and at the time of the braking, the cylinder portion is separated from the disc rotor as it goes to the inner peripheral side of the disc rotor. Thus, the disc brake of the type in which two portions of the outer peripheral surface of the piston that are separated from each other by a predetermined distance in the axial direction and are located on opposite sides in the radial direction of the disk rotor are rubbed while being pressed by the inner peripheral surface of the cylinder bore. The caliper for use, at least the inner peripheral surface of the cylinder bore, the piston during the braking The resin member having substantially the same hardness as the hardness of the piston is integrally embedded in the portion that presses the outer peripheral surface at two locations.

With this configuration, at least the inner peripheral surface of the cylinder bore of the metal cylinder portion is separated from the outer peripheral surface of the resin piston in the axial direction by a predetermined distance during the braking, and the radial direction of the disk rotor is increased. Since a resin member having substantially the same hardness as that of the piston is integrally embedded in the portions that press two locations on the opposite sides of the cylinder, the resin piston does not protrude from the cylinder bore during braking. As a result, the two points on the outer peripheral surface of the resin piston are rubbed while being pressed by the resin member having substantially the same hardness, which allows the outer peripheral surface of the resin piston to be pressed during braking with high hydraulic pressure. Can be preferably prevented from being damaged by the cylinder portion, and the two parts of the outer peripheral surface of the resin piston can be prevented due to slight compressive deformation of the resin member. Since the pressing force applied to the place can be reduced, it is possible to prevent an unreasonable force from being applied to the resin piston in the substantially radial direction of the disc rotor.

The above effect can be obtained by using a resin member or a rubber member having a hardness significantly smaller than that of the resin piston, but in this case, the friction between the piston and the resin member or the rubber member is caused. It is unavoidable that the resistance increases and the sliding resistance of the piston increases. On the other hand, according to the present invention, since the resin member having substantially the same hardness as that of the resin piston is used, the above effect can be obtained without substantially increasing the sliding resistance of the piston.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

In FIG. 1, 10 is a caliper, 12 is a disc rotor,
14 is a torque receiving member. The caliper 10 has a cylinder portion 18 having a cylinder bore 16 that opens toward the disc rotor 12, and integrally extends from the cylinder portion 18 and faces the opening side of the cylinder portion 18 with the outer peripheral portion of the disc rotor 12 in between. It is configured with a bifurcated claw portion 20, and in the cylinder bore 16, a resin-made piston 22 having a bottomed cylindrical shape has a predetermined fitting clearance with its open end facing the disc rotor 12. And is slidably fitted. The annular groove formed on the inner peripheral surface of the cylinder bore 16 and located at the inner side of the opening by a predetermined distance provides a liquid-tight seal between the cylinder bore 16 and the piston 22 and provides a return action for the piston 22. The piston seal 23 formed is fitted.

The torque receiving member 14 is a fixed portion 24 fixed to a non-rotating member (not shown), and a pair of facing portions 26 that extend integrally from the fixed portion 24 and face the fixed portion 24 with the disc rotor 12 in between. 26 (only one is shown) and a connecting portion 28 that connects the facing portions 26, 26 to each other, and a disk of the cylinder portion 18 is formed by a pair of slide pins (not shown) protruding from the fixing portion 24. The calipers (10) are movably supported at portions located on both sides in the circumferential direction of the rotor (12) so as to be movable in a direction parallel to the axis of the disc rotor (12).

A disc rotor 12 is provided between the piston 22 and the claw portion 20.
A pair of pads 30 and 32 are arranged with sandwiching the
One pad 30 is supported by a fixed portion 24 of the torque receiving member 14 so as to be movable in a direction parallel to the axis of the disc rotor 12, and the other pad 32 is provided on the other pad 32.
The opposing portions 26, 26 are movably supported in a direction parallel to the axis of the disc rotor 12.

In the disc brake configured as described above,
When hydraulic pressure is supplied to the liquid chamber 34 formed in the cylinder bore 16, the piston 22 is actuated in the protruding direction to press one pad 30 against one surface of the disc rotor 12, and the reaction force thereof causes the caliper 10 to move. Is moved in the direction opposite to the protruding direction of the piston 22, and the other pad 32 is pressed against the other surface of the disk rotor 12 by the claw portion 20, whereby rotation of the disk rotor 12 is suppressed and braking is performed. At this time, the caliper 10 is, as shown in FIG.
The cylinder portion 18 and the claw portion 20 are slightly opened in a direction in which they are separated from each other, and the cylinder portion 18 is slightly separated from the disk rotor 12 toward the inner peripheral side of the disk rotor 12, whereby the cylinder bore 16 of the piston 22 is formed. Along with the protrusion from the inside, the portion of the cylinder bore 16 located on the inner peripheral surface on the opening side and on the outer peripheral side of the disk rotor 12 and the cylinder bore 16
The inner peripheral surface located inside the piston seal 23 by a predetermined distance and the portion located on the inner peripheral side of the disk rotor 12 are separated from the outer peripheral surface of the piston 22 by a predetermined distance in the axial direction and the disk rotor 12 Two portions located on opposite sides in the radial direction are rubbed while being pressed, and the pressing force increases in accordance with the brake hydraulic pressure in the hydraulic chamber 34.

Here, in the present embodiment, as shown in FIGS. 1 to 3, the portion of the outer peripheral surface of the piston 22 that presses the two portions during braking of the inner peripheral surface of the cylinder bore 16 is
Resin members 36 and 38 having substantially the same hardness as that of the resin piston 22 are integrally embedded, and the resin piston 22 is projected from the cylinder bore 16 during braking. The two points on the outer peripheral surface of 22 are rubbed while being pressed by resin members 36 and 38 having substantially the same hardness as the piston 22. Thereby, even when the two positions of the outer peripheral surface of the resin piston 22 are rubbed while being strongly pressed by the resin members 36 and 38 during braking at high hydraulic pressure, the outer peripheral surface of the resin piston 22 is prevented from being damaged. This can be suitably prevented, and the pressing force of the resin members 36, 38 on the resin piston 22 can be reduced based on the slight compressive deformation of the resin members 36, 38. It is possible to prevent an unreasonable force from being applied in the substantially radial direction of the disk rotor 12. If the outer peripheral surface of the piston 22 is damaged, not only may the smooth operation of the piston 22 be hindered by the damage, but also the amount of protrusion of the piston 22 from the cylinder bore 16 due to wear of the pads 30, 32. Becomes larger and the outer peripheral surface of the piston 22 located on the outer peripheral side of the disc rotor 12 has a longitudinal scratch extending toward the bottom side of the piston 22, and when the piston 22 is pushed into the cylinder bore 16 when the pad is replaced. There is a risk that the brake fluid in the liquid chamber 34 may leak through the scratch as it crosses the piston seal 23, but according to the present embodiment, the outer peripheral surface of the piston 22 is prevented from being damaged. Therefore, both the above-mentioned fears can be suitably solved.

Among the above effects, the effect of ensuring the strength of the resin piston 22 can be more suitably obtained as the hardness of the resin members 36 and 38 is made smaller than the hardness of the resin piston 22, and accordingly, the piston 22 and the resin member It is unavoidable that the frictional resistance with 36, 38 increases and the sliding resistance of the piston 22 increases. On the other hand, according to the present embodiment, since the hardness of the resin members 36 and 38 is substantially the same as the hardness of the resin piston 22, the above effect can be obtained without increasing the sliding resistance of the piston 22. Is obtained.

In the above-described embodiment, the resin members 36, 38 are provided only in a part of the inner peripheral surface of the cylinder bore 16 in the circumferential direction, but an annular resin member is provided over the entire inner peripheral surface of the cylinder bore 16. It may be embedded integrally.

Further, in the above-described embodiment, the case where the present invention is applied to the caliper of the caliper floating disc brake is explained, but even the caliper fixed disc brake caliper has the resin piston. Further, during braking, the cylinder portion is separated from the disc rotor toward the inner peripheral side of the disc rotor, so that the inner peripheral surface of the cylinder bore rubs against the outer peripheral surface of the piston while pressing the two locations. For example, by applying the present invention, the same effect as that of the above-described embodiment can be obtained.

In addition, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of drawings]

FIG. 1 is a sectional view showing an essential part of a disc brake provided with a caliper to which the present invention is applied. FIG. 2 is a view showing a main part of a cross section taken along line II-II in FIG. FIG. 3 is a diagram showing a main part of a cross section taken along line III-III in FIG. 10: Caliper 12: Disc rotor 16: Cylinder bore 18: Cylinder part 22: Piston 36, 38: Resin member

Claims (1)

[Scope of utility model registration request] 1. A resin piston, which has a cylinder portion having a cylinder bore that opens toward a disc rotor and is laid across the outer periphery of the disc rotor, and is slidably fitted in the cylinder bore. The braking is performed based on the protrusion from the cylinder bore, and at the time of the braking, the cylinder portion is separated from the disc rotor toward the inner peripheral side of the disc rotor, so that the axial center of the outer peripheral surface of the piston is In a disc brake caliper of a type that is rubbed while being pressed by the inner peripheral surface of the cylinder bore at two locations that are separated from each other by a predetermined distance in the radial direction of the disc rotor, the inner peripheral surface of the cylinder bore At least the portion that presses the outer peripheral surface of the piston at the time of the braking is hardened by the piston. A disc brake caliper in which a resin member having substantially the same hardness as that of the above is integrally embedded.