Brake disk producing method and brake disk

Abstract

A brake disk producing method, comprising a periphery pressing step for forming an outer peripheral shape (5) of a rotor plate (2) into a peripheral shape having recesses and ridges (5a, 5b) repeated in a radial direction, and a chamfering step for forming a chamfered surface (6) by pressing, against a corner portion (2d) on an outer peripheral edge of the rotor plate (2), a die (7), and a brake disk made by the method. Accordingly, it is possible to improve heat radiation capability, reduce the weight and moment of inertia, improve safety in handling, and suppress increase in production costs. Furthermore, by forming the chamfered surface (6), the amount of wear of a brake pad pressed by the brake disk (1) can be reduced, and durability of braking performance can be maintained or improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of producing a brake disk whose outer peripheral shape is formed to have recesses and ridges repeated in the radial direction and to the improvement of the brake disk, in a brake disk of a disk brake device used in a motorcycle and the like. BACKGROUND ART [0002] Because of its compact size, light weight, large absorbed energy and stable braking force, a disk brake device is used widely as a brake device for a motorcycle, a car, a pickup truck, or the like (see Japanese Patent Application Laid-Open No. 2003-74604, for example). As the main component of such disk brake device, there is a brake disk. The brake disk rotates integrally with a wheel, transmits, to the wheel, braking force caused by the pressure of the brake pad pressing against the both surfaces of the brake disk, and has a function of radiating frictional heat generated between the brake disk and the brake pad at the time of braking. In terms of the outer ...

AI Technical Summary

Benefits of technology

[0023] In addition, in the method of producing a brake disk, the a chamfered length from the corner portion on the outer peripheral edge of the rotor plate toward a direction of a surface contacting with the brake pad, and a chamfered length from the corner portion toward a direction of an outer peripheral end surface are greater than or equal to 0.1 mm and less than or equal to 2.0 mm, preferably greater than or equal to 0.1 mm and less than or equal to 1.0 mm, or more preferably greater than or equal to 0.2 mm and less than or equal to 0.7 mm. Hence, the effect of preventing nonuniform wear of the brake pad pressed by the brake disk produced in the production method, and the effect of reducing the amount of wear become significant.

[0024] The brake disk according to the present invention is a brake disk rotating integrally with a wheel, wherein a recessed and ridged portion which is uneven in a radial direction is formed repeatedly on an outer peripheral edge of a rotor plate of the brake disk along a circumferential direction, and a chamfered surface is provided on a corner portion of the recessed and ridged portion by means of press molding. Accordingly, it is possible to improve heat radiation capability, reduce the weight and moment of inertia, improve safety in handling, and suppress increase in production costs. Further, the amount of wear of the brake pad pressed by the brake disk can be reduced by forming the chamfered surface. In addition, an impression of the repeated shape of recesses and ridges and of the chamfered surface can improve the design.

[0025] Further, a cut-processed outer peripheral surface is formed in a leading end portion of a ridged portion of the recessed and ridged portion by cut-processing a part on the leading end side of the ridged portion in accordance with a circular arc of a circle concentric with the center of rotation of the rotor plate, and a chamfered surface which is cut-processed on a corner portion of the cut-processed outer peripheral surface by means of cut-processing is provided so as to continue to the chamfered surface obtained by means of the press molding. Accordingly, it is possible to improve heat radiation capability, reduce the weight thereof, reduce moment of inertia, improve safety in handling, and suppress increase in production costs. In addition, an impression of the repeated shape of recesses and ridges and of the chamfered surface can improve the design. Further, accuracy of the shape of the portion of the rotor plate where an outer diameter is largest and deflection accuracy at the time of rotation can be enhanced.

[0026] Further, the recessed and ridged portion is formed by means of press molding, a chamfered surface is formed, by pressing, on each side of the recessed and ridged portion where a corner portion has no sag, and the side of the recessed and ridged portion where a corner portion has sag is made to serve as an attaching surface to the wheel. Accordingly, increase in production costs can be further suppressed.

[0027] Further, a chamfered length of the chamfered surface corresponds to the size of the sag of the corner portion on the outer peripheral edge of the rotor plate, the sag being formed by means of the press molding, thus an integrated impression can be obtained to enhance design. Moreover, the amount of wear of the brake pads on both sides which are pressed by the brake disk can be reduced, and the amount of wear of the both brake pads can be made substantially even.

[0028] In addition, in the brake disk, a chamfered length from the corner portion on the outer peripheral edge of the rotor plate toward a direction of a surface contacting with the brake pad, and a chamfered length from the corner portion toward a direction of an outer peripheral end surface are greater than or equal to 0.1 mm and less than or equal to 2.0 mm, preferably greater than or equal to 0.1 mm and less than or equal to 1.0 mm, or more preferably greater than or equal to 0.2 mm and less than or equal to 0.7 mm. Hence, the effect of preventing nonuniform wear of the brake pad pressed by the brake disk, and the effect of reducing the amount of wear become significant.

Problems solved by technology

Although the brake disk, whose outer peripheral shape is formed to have recesses and ridges repeated in the radial direction, is preferred in terms of its improved heat radiation capability, light-weight body, improved design and the like, the brake disk with such outer peripheral shape has problems that the brake pad wears out significantly and the processing cost for molding the brake disk rises.

Particularly, in a case of forming a chamfered surface at a corner portion of an outer peripheral edge of the brake disk out of consideration for safety, design and the like, the processing for the formation needs to be carried out for a long period of time using an expensive processing machine or special processing machine such as an NC machining tool or the like since the outer peripheral shape is formed to have recesses and ridges repeated in the radial direction.

Therefore, the processing cost for the formation of a chamfered surface increases significantly.

For this reason, the brake disk, whose outer peripheral shape is formed to have recesses and ridges repeated in the radial direction, comprises the characteristics of the improved heat radiation capability, the light weight body, the improved design and the like, but has, on the other hand, a problem that such brake disk lacks practicability due to the poor durability of the braking performance and high production costs.

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