JPS6125482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a brake ring for an internally expanding drum brake used for a vehicle. Brake rings are the main components of drum brakes that work together with brake shoes, and are usually made of cast iron or high-grade cast iron, and are used by being cast into a light alloy brake drum. This invention relates to finishing of a brake ring prior to casting into a brake drum. More specifically, it relates to a manufacturing method that uses a material in which two parts are integrally cast, turns the material to finish the braking surface, and cuts it into two parts. The goal is to finish semi-finished products efficiently during the process.

Conventionally, when cutting out two brake rings from a two-cavity casting material, processing of both end faces, processing of the inner circumferential surface, and cutting-off process were performed separately, so the material had to be reattached to the chuck each time. This made it difficult to improve products.

This invention is an improvement that allows the end face milling process and the cutting process to be performed at the same time by checking each brake ring separately in advance, which becomes two pieces after cutting when performing the parting process.

The present invention will be explained below with reference to illustrated embodiments.
FIG. 1 shows a brake ring manufactured by the manufacturing method of the present invention. That is, the brake ring 1 has a short cylindrical shape, and has an inner circumferential surface 1a, which is a braking surface, and both end surfaces 1b, 1b, which are finished by cutting, and an outer circumferential surface 1.
c is as-cast. 1d is a plurality of protrusions protruding from the outer circumferential surface and acts as a rotation stopper when molded into a brake drum (not shown). 1e is a chamfer formed on the outer surface of both ends.

In Fig. 2, reference numeral 2 denotes a claw chuck consisting of a known collection chuck operated by hydraulic or pneumatic pressure, which is provided to grasp the raw material or semi-finished product of the brake ring 1, and in Figs. 2a and 2b for the inner circumference in FIG. 4 are shown, respectively. 2c is the main body of the claw chuck 2. 3 is a material made by integrally casting two brake rings, and is made of high-grade cast iron into a cylindrical shape. The small annular protrusions 3a on the inside and outside of the material 3 are cast burrs generated in correspondence with the mating parts of the casting mold.
The pawl chuck 2 is provided with a relief 2d to avoid casting burrs 3a. FIGS. 3 and 5 show the positional relationship of each cutter at the end of the first or second process, and each cutter has a first tool rest 4 that moves in the direction of the axes C and L of the claw chuck, and an axis C, It is supported by a second tool rest 5 having a front half 5a and an opposite half 5b that move forward and backward in a plane perpendicular to L, and these constitute a turning unit. That is, the first tool rest 4 supports a chamfering tool 6, an inner circumferential cutting tool 7, and a front tool 8 for cutting the end surface 1b opposite to the claw chuck 2, and each tool is secured by a bolt 9. It consists of a shank 11 screwed onto the first tool rest 4 and a throwaway type carbide tip 12 bolted to the tip of the shank 11.

In the second tool rest 5, a chamfering tool 14 and a cut-off tool 15 are supported on the front half 5a in the same way as the first tool rest 4, and two of the same shape are supported on the opposite half 5b. Chamfering bits 16 are arranged in parallel.

The parting tool 15 is a conventionally known tool having a thin carbide tip brazed onto the shank.

Next, the processing order of the brake ring 1 will be explained.
First, as shown in FIG. 2, the first step is to abut one end of the material 3 against the main body 2c of the claw chuck, and then move the outer circumferential claw chuck 2a in the direction of the axis C and L to tighten the outer periphery of the material 3. Then, the pawl chuck 2 is rotated and the first tool rest 4 is moved to the right in the figure to cut the inner circumferential surface 1a, end surface 1b, and outer circumferential chamfer 1e as shown in FIG.

In the second step, the material 3 that has completed the first step is turned in the opposite direction and abutted against the claw chuck body 2c, and then the inner circumferential claw chuck 2b is expanded in the radial direction to face the inner circumferential surface cut in the previous step. 1a and while rotating the claw chuck 2, first, as shown in the upper half of FIG. The cast flash 3a is removed and the cut portion is chamfered in a triangular shape.

Next, the front half 5a advances in the direction of arrow B to finish the end face 1b, and the cutting tool 15 plunges into the triangular chamfered area in the center to cut into the two brake rings 1,1. Two brake rings 1 can be obtained by retracting the tool rest 5a on the rear front side and reducing the pawl chuck 2b.

As described above, this invention is based on the material 3 which is made by adding machining allowance to the length of two brake rings 1 arranged in the axial direction.
A turning unit having a first turret and a second turret is prepared, and one end surface and inner peripheral surface of the material are cut in the first step, and the other end surface of the material is cut in the second step. Because there is, you only need to attach and detach twice.
Since individual brake rings can be obtained, there is less labor required for attaching and detaching materials, and productivity is high. Further, since the turning unit is easily available and does not require major modification, it has the advantage of requiring less capital investment and being economical.

[Brief explanation of the drawing]

The drawings show an example of the implementation of the present invention. Fig. 1 is a cross-sectional view of a brake ring as a product, Fig. 2 is a cross-sectional view showing the start of the first process when the brake ring material is attached to a turning unit, and Fig. 3 The figure is a cross-sectional view corresponding to Figure 2 showing the end of the first process, Figure 4 is a cross-sectional view showing the start of the second process, and Figure 5 is a cross-sectional view corresponding to Figure 4 showing the end of the second process. It is a diagram. 1... Brake ring, 2... Claw chuck, 4
...First turret, 5...Second turret.

Claims (1)

[Claims] 1. A pawl chuck and a first chuck that moves in its axial direction.
A turret and a turret that moves in a plane perpendicular to the axis.
Using a grinding unit consisting of a second tool rest,
A first step of gripping the outer peripheral surface of a cylindrical material having a length more than twice the length of the product with a claw chuck and turning at least one end surface and the inner diameter of the material using a cutting tool attached to a first tool post; The inner peripheral surface of the semi-finished product that has completed one process is gripped by a claw chuck, and at least two cutting tools attached to the second tool post are used to cut and cut off the other end surface of the material by moving the second tool post. and a second step of dividing the product into two products by this cut-off cutting. 2. The method for manufacturing an inwardly expanding brake ring according to claim 1, wherein the claw chuck that grips the inner periphery of the semi-finished product is provided with a notch in the circumferential direction on the central outer peripheral surface of the gripping claw.