JPS6046831A - Joining method of constituted pipe in silencer - Google Patents

Abstract

PURPOSE:To couple firmly joining end edges by providing a circular projecting piece and a recessed part corresponding to said piece on the joining end edge of a steel plate, raising neck part both edges of the recessed part at the time of joint, fitting the projecting piece into the recessed part, and thereafter, pressing and restoring the neck part both edges. CONSTITUTION:A long-sized steel plate is cut to a desired length (d), and a steel plate 1 with a silencing hole 4, which has a circular projecting piece 2 having a neck part of a narrow width on one side, and a recessed part 3 of the same shape as the projecting piece 2 on the other side is punched. Subsequently, the steel plate 1 is bent and formed to a cylindrical shape, the projecting piece 2 is fitted into the recessed part in a state that neck part both enges 3a of the recessed part 3 are raised upward, and thereafter, both the edges 3a are pressed and welded by pressure to the edge of the projecting piece 2. In this way, both end edge parts of a pipe constituting steel plate can be fitted and coupled firmly, and also a yield of the base material steel plate is not lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of joining both ends of a pipe forming a muffler for muffling exhaust gas from an internal combustion engine, which is formed by bending a steel plate.

Conventionally, this type of pipe is constructed by bending a steel plate in which a resonant hole is formed and joining the joined edges together. Conventionally, this type of edge joining method includes a method in which the joint is welded at a point (A) as shown in Fig. 1, or a method in which the joint is made for seaming as shown in Fig. 2. be. The former method has disadvantages such as local thermal distortion caused by heating the material and the need for a machining process to correct the diameter, and the latter method requires extra material for the wrap. was there.

The purpose of this invention is to propose a joining method that eliminates the above-mentioned drawbacks, namely, a circular protrusion with a narrow neck is formed on one joining edge of a steel plate having a resonance hole (4). Place piece (2) on the other joining edge.

Four parts (3) having the same shape as the protruding piece (2) are positioned so that they will join together when both ends are joined, and such a steel plate is first attached to both necks of the four parts (3). Class (3a), (
The projecting piece (2
) is fitted into the recess (3), and then a compression process is performed to restore both edges (3a) and (3g) of the neck of the erected recess. 3a)
This is characterized in that both edges are joined using the connecting element.

Next, embodiments of the invention shown in the drawings will be described.
(1) is a pipe-constituting steel plate, which is formed by press punching from a long raw steel plate as follows.

That is, a long material steel plate is cut transversely at a desired interval (d) in its longitudinal direction, and a circular part having a narrow neck is formed at a part of the cutting line. A circular protrusion (2) with a narrow neck is formed on one side of the cut constituent steel plate, and a recess (3) having the same shape as the protrusion is formed on the other side. The structural steel plate (1
) to form. As a result, in the constituent steel plate (1), the protrusion (2) and the recess (3) of the same shape are formed at the same position, and there is no loss of material. Next, such a constituent steel plate (1) is bent into a cylindrical shape using a normal bending press, and the edges are joined together, and at the same time, the projecting piece (2) is fitted into the recess (3). Prior to this fitting, the recess (
Both edges (3B), (3B) of the neck part of 3) are made to stand upwards, and in this state, the protruding piece (2) is fitted, and then the both edges (3a), (3a) are pressed and flattened. Make it. This makes it easy for the protrusion (2) to enter the recess (3) from diagonally above when mating, and also plastically deforms both edges of the recess (3) during the pressurizing process, causing the protrusion ( 2), and the fitting of the protruding piece into the recess becomes strong. The shape of the protruding piece (2) is as shown in FIG.
The diameter R of the head is 12, the distance from the joining edge to the center of the head is 6, the cutting radius r of the base is 1%, the width d of the base is 10
It is good to say. In the figure, (4) shows resonance holes formed by punching. A pipe formed in this way (
1a) as shown in Fig. 7, the outer cylinder (5), the side wall (6)
, a support wall (7), etc. to constitute a muffler.

By firmly fitting both sides of the pipe (1a) into the holes provided in the support wall (7) in this manner, the pipe does not open against internal pressure. Note that although the number of protrusions (2) and recesses (3) are provided in the embodiment shown in the drawings, this number is not limited.

As described above, according to the present invention, both end edges are connected by fitting the circular protrusion (2) having a narrow neck into the recess (3) having the same shape, and furthermore, During the bending process, both edges (3B) and (3a) of the neck of the fourth part (3) are once erected, so that the protrusion (2) has a circular shape relative to the recess (3). They fit together very naturally and smoothly.

The upper parts # (3B) and (3B) are plastically deformed by the pressing process to restore them, and are strongly crimped to both outer sides of the neck of the protrusion, resulting in a strong fit using the core as a connecting element. This is a method that performs binding and is extremely effective in practice.

[Brief explanation of drawings]

7 and 2 are perspective views of a pipe with a conventional joining structure, FIG. 3 is a plan view of a steel plate before bending showing the present invention, FIG. 1 is a perspective view of the steel plate joined into a pipe shape, and FIG. 4 is an enlarged plan view of the protrusion, FIG. 4 is an enlarged plan view of the recess, and FIG. 7 is a schematic sectional view of the muffler. (1)...Steel plate (2)...Protruding piece (3)...Recess Patent applicant Co., Ltd. 35

Claims (1)

[Claims] A circular protrusion (2) with a narrow neck is attached to one joint edge of the steel plate having the resonance hole (4), and a recess (3) having the same shape as the protrusion (2) is attached to the other joint edge. ) are positioned so that they join together when both edges are joined, and such steel plates are first attached to both edges (3a) + (3) of the neck of the recess (3).
a) is made to stand upwards and then bent into a cylindrical shape using a known method to bring both ends into contact with each other, and the projecting piece (2)
is fitted into the recess (3), and then a compression process is performed to restore the raised neck parts (3a) and (3a) of the recess, and the compression process allows both edges (3a) t (3a)
A method for joining component pipes in a silencer, characterized in that both ends of the pipes are joined using the pipe as a joining element.