JPS6143127B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simply and accurately assembling tubular members so that they can slide in the radial direction.

For assembled parts that are repeatedly heated and cooled, such as exhaust port parts used for automobile exhaust gas countermeasures, gaps of predetermined dimensions must be maintained with precision to withstand thermal expansion and contraction. It is necessary to do this and join them.

Conventionally, however, each member shown in FIG. Next, a ring 3 having an inner diameter larger than the outer diameter of the flange pipe 2 and smaller than the outer diameter of the flange 2a is fitted from the upper part of the flange pipe 2, and the ring 3 and the rising part 1b of the stepped tubular member are connected to each other as indicated by arrows in the figure. It was assembled by welding the tip to the tip (Figure 1B). However, with the above method, it is difficult to accurately set a gap that allows the two parts to slide smoothly in the radial direction. In other words, in the conventional method, it is necessary to accurately process the height of the rising portion 1b of the stepped tubular member, and even if the height is accurate, distortion occurs due to the heat of welding, and its dimensions are difficult to guarantee. It was hot. Also, the procedure is complicated and the number of parts is at least 3.
The process requires a large number of pieces, which is extremely poor in terms of productivity and increases costs.

The present invention solves the above-mentioned drawbacks and provides a method in which two parts can be assembled in a slidable manner with high accuracy, and the assembly is easy, thereby improving productivity.

That is, in the method of assembling two parts according to the present invention, after forming a slit groove along the inner periphery at the position on the inner surface of the rising part of the stepped tubular member where it is to be bent, the outer diameter of the flange part is attached to the stepped part of the member. The flange portion of another component, which is slightly smaller than the inner diameter of the stepped portion, is placed on a fugitive sheet such as paper, and the tip of the rising portion of the tubular member is bent inward at right angles from the slit groove, and then The method is characterized in that the sheet is removed by a removal means such as burning or melting.

The assembly method according to the present invention will be explained with reference to FIG. Figure A). A slit groove 1c is formed along the inner periphery at a position on the inner surface of the rising portion 1b of the obtained stepped tubular member 1 where it is to be bent (FIG. 2B). In this case, the slit groove 1c preferably has a V-shaped cross section as shown in FIG. Next, the upper end 1b' was pressurized through the slit groove 1c formed at the desired position to preform it into a tapered shape (Fig. 2C), and then the circular or central part was punched out to the same size as the inner diameter of the tubular member 1. The ring-shaped paper (washier) 4 and then the flange tube 2 are placed in order (FIG. 2D). At this time, the thickness of the paper 4 is set to correspond to the desired gap between the two members of the finally obtained assembled product, and is preferably about 0.05 to 0.1 cm thick. Finally, the rising upper end portion 1b', which was preformed in the above step and is slightly curved inward, is further bent at a right angle to complete the assembly (FIG. 2E).

When the assembly member obtained by the above method is exposed to high temperature, the gap determining paper 4 is burned out, and a predetermined gap is obtained between the stepped member 1 and the flange tube 2, satisfying the dimensional specifications. In the case of an exhaust pipe, if the paper 4 is applied to the area of use with the paper 4 still attached, the paper will be burned away by the temperature of the exhaust gas. In addition to the above-mentioned paper, the material used to determine the gap may be any material that is easily flammable or soluble in water, such as a burnable or water-soluble plastic sheet, which is removed by burning or dissolving in water after assembly.

A more specific processing example is shown in FIG. 3. In the process of making slit grooves in the stepped member, for example, as shown in FIG. The grooving cutter 5 is inserted into the taper cone 6 and expanded to form a groove 1c having a V-shaped cross section into a ring shape on the inner surface of the stepped member rising portion 1b. Then, a cup-shaped punch 8 is used to press and preform the rising portion 1b (FIG. 3B). Further, after placing the ring-shaped gap determining paper 4 and the flange tube 2, the rising upper part 1b' is lightly pressed with a flat punch 9 to assemble it (FIG. 3C).

An example of an assembled product A obtained by the above method is shown in FIG. This product A is an example of an exhaust port part for exhaust gas countermeasures, and a gap of 0.05 to 0.1 mm is maintained between the two pieces B and C, and the amount of movement in the circumferential direction is 2.5 mm. Therefore, this product A can move smoothly in the circumferential direction, which is very useful in terms of its function.

Furthermore, the method of the present invention is also useful when it is desired to bend a member at right angles in sheet metal press working. That is, in general sheet metal processing, thin plates are often bent from the point of view of product function, but in this case there is a problem in that a radius is formed near the bent portion and the flat surface accuracy is poor. However, if the method of the present invention is used, slit grooves are provided in advance at the positions to be bent, so the bending can be performed with high precision.Furthermore, a sheet of paper is inserted between the two parts to determine the thickness, so the parts can be assembled with a high-precision gap. An attached product is obtained.

As is clear from the above description, if the method of the present invention is used, paper or the like is used to determine the thickness, and heat treatment such as welding is not performed, so the gap between the two pieces can always satisfy the specified accuracy. Furthermore, the number of parts required is smaller than that of conventional methods, resulting in significant productivity improvements and cost reductions.

[Brief explanation of the drawing]

Figures 1A and 1B are cross-sectional views of welding type assembly parts and products by the conventional method, Figures 2A to 2E are cross-sectional schematic diagrams showing the principle of the assembly process by the method of the present invention,
3A to 3C are schematic cross-sectional views showing one embodiment of the assembly process according to the method of the present invention, and FIG. 4 is a cross-sectional view of an assembled product obtained by the method of the present invention. In the figure, 1... stepped tubular member, 2... flange pipe, 3... ring, 4... ring-shaped paper, 5... grooving cutter, 6-8... punch, A... assembled product, represents.

Claims (1)

[Claims] 1. After forming a slit groove along the inner periphery at the position on the inner surface of the rising part of the stepped tubular member where it is to be bent, attach another part to the stepped part of the member whose outer diameter is slightly smaller than the inner diameter of the stepped part. The flange portion of the tubular member is placed on a fugitive sheet such as paper, the tip of the rising portion of the tubular member is bent inward at right angles from the slit groove, and then the sheet is removed by a removal means such as burning or melting. A method for assembling two parts, characterized by removing them.