Patent ID: 8083035
Filing Date: 2011-12-27
Classification: B23K,F15B,F16D,Y10T

Abstract:
1. A method for manufacturing a disk brake comprising a first cylinder disposed on one side of a disk, a second cylinder disposed on the other side of the disk, and a disk pass portion connecting the first cylinder and the second cylinder on an outer radial side of the disk, wherein pistons are caused to slidingly move in bores of the first and second cylinders under application of a hydraulic pressure and thereby press a brake pad against a disk, the method comprising: providing a covering member in a bottom portion of the first cylinder; providing a cylinder body which has an opening that is closed by the covering member, the cylinder body comprising a cylinder portion defining an internal diameter portion of the bore, an inner annular flange portion extending radially inwardly from the bottom portion side of the cylinder portion and defining the opening, and an outer circumferential portion on the bottom portion of the first cylinder, wherein the opening has an inner diameter that is smaller than that of the bore, wherein a major part of the outer circumferential portion has a circular shape, and a part of the circular shaped outer circumferential portion is provided with a bulge portion extending outwardly in a radial direction of the cylinder portion; supporting the covering member and the inner annular flange portion by abutting a flat surface of a support inserted into the bore against a flat portion on the bore bottom surface side of the inner annular flange portion and an inner flat portion of the covering member so that the flat portion on the bore bottom surface side of the inner annular flange portion and the inner flat portion of the covering member become level with each other; and connecting the covering member and the cylinder body by friction stir welding along an entire periphery of the covering member while the flat surface of the support supports the inner annular flange portion and the covering member to form a connecting portion surrounding the covering member in the form of a closed loop, and then moving a welding tool outwardly in the radial direction of the cylinder body from the closed loop connecting portion through a substantial extent of the bulge portion such that a central hole of a residual impression of the welding tool is positioned outwardly of an inner diameter of the bore, and removing the welding tool from the cylinder body, to produce the first cylinder of the disk brake from the covering member and the cylinder body, wherein the bulge portion is formed at a position corresponding to the disk pass portion in the circumferential direction of the cylinder body, and the bulge portion extends continuously from an outer end surface on the bottom portion side of the first cylinder to the disk pass portion in the axial direction of the disk, and wherein the bulge portion includes a flat surface continuous with the outer end surface of the first cylinder.