Brakes – Wheel – Axially movable brake element or housing therefor
Reexamination Certificate
1998-06-01
2001-02-06
Butler, Douglas C. (Department: 3613)
Brakes
Wheel
Axially movable brake element or housing therefor
C188S073310, C188S073100, C188S073350
Reexamination Certificate
active
06182801
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a disc brake device and, more particularly to a disc brake device in which a brake torque applied to an outer pad is supported by a vehicle body through a caliper.
DESCRIPTION OF THE PRIOR ART
Conventionally, there is known a disc brake device in which a brake torque applied to an outer pad is supported by a vehicle body through a caliper, and a brake torque applied to an. inner pad is supported by a support member. This disc brake is composed as follows. There is provided a caliper striding a rotor. This caliper is held by a pair of guide pins, so that the caliper can be moved in the axial direction of the rotor. In this case, the pair of guide pins are attached to the support member, which is fixed to the vehicle body, on the inner side, and these guide pins extend in a direction opposite to the rotor. The inner pad is pressed against the rotor by the action of a hydraulic cylinder provided on the inner side of the caliper, and at the same time, the caliper is moved by the reaction force, so that the outer pad can be pressed against the rotor by the action of a caliper claw on the outer side. In this case, the outer pad is combined with the caliper claw by the engagement of a protrusion with a recess, so that a brake torque of the outer pad can be transmitted to the caliper claw.
In the disc brake composed in the manner described above, brake torque is supported by the vehicle body as follows. Brake torque applied to the inner pad is supported by the support member, and brake torque applied to the outer pad is transmitted to a guide pin on the rotor run-in side through the caliper claw, so that the torque can be supported by the vehicle body. Due to the foregoing, a main guide pin of large diameter is conventionally arranged on the rotor run-in side, and a sub-guide pin of small diameter is arranged on the rotor run-out side. While the error caused in the process of manufacture is absorbed in this way, brake torque applied to the outer pad is supported by the main guide pin of large diameter. On the back plate of the outer pad, there is provided a protrusion which engages with a torque transmitting hole formed in the caliper claw as disclosed in Japanese Unexamined Utility Model Publication No. 62-130233.
However, in the disc brake composed as described above, the following problems may be encountered. The outer pad and the caliper are combined with each other by the engagement of a protrusion and a recess, however, in order to absorb an error caused in the process of manufacture, the outer diameter of the protrusion is determined to be smaller than the inner diameter of the recess. Due to the above structure, the outer pad tends to vibrate when the brake is applied. In the same manner, in order to move the caliper, to which the brake torque of the outer pad is transmitted, in the axial direction of the rotor, an arm extended from the side of the caliper is opposed to this support at a position on the vehicle body side, and a guide pin attached to the support member is inserted into the caliper arm. Accordingly, the guide pin is arranged in the inner side of the rotor, and the caliper supported by this guide pin holds the outer pad by the claw extended onto the outer side of the rotor.
Therefore, when brake torque is applied to the outer pad, noise is generated around the outer pad by the vibration of the side of the outer pad on which the surface pressure is low. In the same manner, when the brake is applied, an angular moment is generated round the main guide pin. Therefore, both the inner and the outer pads are not made to come into pressure-contact with the rotor in parallel with each other by the deformation of the overall caliper. Accordingly, there is caused a problem of uneven wear.
When brake torque is generated, the main guide pin supports the brake torque. In this case, although a rubber bush is attached to the sub-guide pin of small diameter, the sub-guide pin is deformed when the brake torque is applied. Accordingly, by the generation of the angular moment described above, the caliper and the support member are vibrated, and generate noise.
The present invention has been accomplished to solve the above problems. It is an object of the present invention to provide a disc brake device characterized in that: generation of noise is reduced when brake torque is supported by the main guide pin in the braking process and torque applied to the outer pad is precisely transmitted, so that vibration of the outer pad and caliper is suppressed; and generation of plane angular moment of the caliper is suppressed, so that uneven wear of the pad can be reduced.
SUMMARY OF THE INVENTION
In order to accomplish the above object, the present invention is to provide a disc brake device in which a caliper is guided with respect to a support member by a pair of guide pins including a main pin and a sub-pin, and a back plate of an outer pad and the caliper are engaged with each other by the engagement of a plurality of protrusions and recesses arranged in the circumferential direction of a rotor so that brake torque applied to the outer pad can be transmitted through the caliper and the main pin, wherein the pair of guide pins and guide holes of the support member into which the guide pins are inserted extend while they are striding the rotor, and exceed a facing portion where the rotor faces the outer pad, and the main pin is arranged on the rotor run-out side and brake torque applied to the outer pad is transmitted by a protrusion and recess engaging section arranged on the rotor run-out side.
In this case, a distance between the centers of the protrusions or recesses on the outer pad side in the protrusion and recess engaging section of the outer pad and the caliper is larger than a distance between the centers of the recesses or protrusions on the caliper side.
Since the main guide pin is arranged on the rotor run-out side, an amount of wear of the outer pad is larger on the rotor run-out side due to the torsional deformation of the caliper. Accordingly, the rotor run-out side of the outer pad tends to vibrate when a light load is given to the brake, however, in the present invention, the outer pad protrusion and recess engaging section on the rotor run-out side, which tends to vibrate, can support a torque by the above arrangement, so that the occurrence of vibration can be effectively suppressed and the effect of reducing noise can be enhanced.
In the case where brake torque is generated in the outer pad, brake torque is transmitted to the main guide pin arranged on the rotor run-out side through the caliper and further transmitted to the support member from the guide hole in which this main guide pin is accommodated. The main guide pin and the guide hole are so long that they stride the rotor and extend to a surface on which the outer pad and the rotor come into contact with each other. Due to the above arrangement, the point of application of brake torque in the axial direction of the rotor coincides with the support membering point, that is, no offset is provided. Therefore, even if torsional deformation is caused by braking in such a manner that the outer side of the caliper comes close to the main guide pin side, the overall surface of the main guide pin can support torque on the extension of a force acting on the outer pad by the rotor, and a force to generate an angular moment is suppressed. Due to the foregoing, the caliper can behave smoothly, and the generation of noise can be reduced and further the occurrence of uneven wear can be prevented.
REFERENCES:
patent: 4121699 (1978-10-01), Tsuruta et al.
patent: 5129487 (1992-07-01), Kobayashi et al.
patent: 5890566 (1999-04-01), Yoshida et al.
patent: 5931267 (1999-08-01), Iwata et al.
patent: 55-122542 (1980-08-01), None
patent: 62-130233 (1987-08-01), None
patent: 64-21824 (1989-02-01), None
patent: 6-503636 (1994-04-01), None
patent: 9-250572 (1997-09-01), None
patent: 9814714 (1998-04-01), None
Odaka Seiya
Shibayama Kazuyuki
Yoshida Hirokazu
Akebono Brake Industry Co. Ltd.
Butler Douglas C.
Morgan & Lewis & Bockius, LLP
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