JPS6050534B2 - Eccentric drawing method for pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for eccentrically drawing the end of a pipe, which is a workpiece, using a press.

Conventionally, in order to obtain a pipe-shaped molded product whose end portion is eccentrically drawn, a processing method in which a flat plate is drawn using a hydraulic press or a bulge processing method have been generally used.

However, the former method of drawing from a flat plate has the disadvantage that the drawing depth (dimension in the longitudinal axis direction) is limited to less than 1:10 with respect to the diameter of the formed pipe, and the latter method of bulge processing has the disadvantage that This method has the disadvantage that it requires large equipment costs and, like the former processing method, the dimension in the longitudinal axis direction is restricted. In view of the above circumstances, it is an object of the present invention to provide a method for forming a molded product having a shape in which the end of a pipe is eccentrically drawn, while being subject to constraints in the longitudinal axis direction and at a low equipment cost. The theoretical gist is that the drawing angle radius of each bowl-shaped recess of a plurality of molds is formed by forming an inner wall surface with a diameter part and a bowl-shaped recess connected to this diameter part as a drawing part. The diameter of the pipe is gradually reduced with respect to the diameter of the pipe that is the workpiece, and the central axis of each diameter part is eccentrically eccentric with respect to the central axis of the pipe. The process involves eccentric drawing of the end of a pipe, which is a workpiece, by sequentially pressing the ends. DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete example of the eccentric drawing method for a pipe according to the present invention will be described below with reference to the drawings.

Figure 1 shows the first, intermediate, and final steps of the press working process in which the workpiece, a round pipe A made of copper or iron, is eccentrically drawn in stages by each of the molds 1a, lb, and lc. The molds for the first process 1a) for the intermediate process lb) for the final process lc and for other processes not shown have their inner wall surfaces as the diameter part 2. A bowl-shaped concave portion 3 connected to the diameter portion 2 forms a constricted portion. Among the drawing parts of these molds 1a, lb, and lc, the drawing angle radius RD of each of the bowl-shaped recesses 3 is not changed and is all formed to be the same. Next, each mold 1
Among the narrowed parts a, lb, and lc, the diameter part 2 is as follows from the mold 1a in the first step to the mold lc in the final step.
The diameter of each diameter portion 2 is decreased in five steps with respect to the diameter of the pipe A, which is the workpiece, and the central axis of each diameter portion 2 is eccentrically eccentric with respect to the center axis 1 of the pipe A. It is formed by The upper end (lower end) of the pipe A, which is the workpiece, is fixed to the base by the molds 1a, lb, and lc of each process formed as described above.

) are successively pressed in the direction of the arrows, and the upper end of the vibrator A is eccentrically drawn in stages as shown by the dashed line, until a molded product D is formed in the final step. As described above, according to the method for eccentric drawing of a vibrator according to the present invention, since the eccentric drawing is performed by pressing the end of the vibrator as the workpiece in stages, even if eccentric drawing is used, it is possible to Unlike hydraulic press drawing or pulge processing methods, it is possible to press a molded product in the shape of a vibrator with eccentric drawing at the end without being constrained in the longitudinal axis direction. Therefore, it can be molded using a normal mechanical press, and has the advantage of requiring low equipment costs.

Furthermore, according to the processing method of the present invention, the bowl-shaped recesses of each mold used in each pressing process are all formed the same without changing the drawing angle radius, so lathe processing is required to manufacture such molds. Milling is sufficient, and there is no need to manufacture a special mold by electric discharge machining, which has the advantage of making the mold easy to manufacture and reducing mold cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a part of each step of the eccentric drawing method for a vibrator according to the present invention, and FIG. 2 is a plan view showing the outline of FIG. 1.

Claims (1)

[Claims] 1 The diameter of each caliber part can be machined without changing the drawing angle radius of each bowl-shaped concave part of a plurality of molds whose inner wall surface is formed by a caliber part and a bowl-shaped concave part connected to this caliber part and used as a drawing part. The ends of the pipe are sequentially pressed using molds that are gradually reduced in diameter with respect to the diameter of the pipe, and the central axes of the respective diameter parts are eccentrically eccentric with respect to the central axis of the pipe. A method for eccentrically drawing a pipe, which comprises eccentrically drawing the end of a pipe that is a workpiece.