JP2001300655A - Method for attaching parts to tubular body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely attach parts to a tubular body without welding. SOLUTION: The tubular body 2 is restricted between an upper die 15 and a lower die 16, while introducing a relative low pressure liquid 10 in the tubular body 2, punches 11, 12 are acted to a tube wall, holes 13, 14 are pierced by the punches 11, 12, at the same time, conical bulged parts 17, 18 are formed to the peripheral part of the holes 13, 14, successively, stepped parts are press fitted into the holes 13, 14, one bulged part 18 is mechanically pushed back by a level difference, successively, by introducing a relative high pressure liquid 10 in the tubular body 2, the other bulged part 17 is pushed back by a liquid pressure, the parts are fastened/fixed in the holes 18, 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting a component on a tube wall of a tubular body.

[0002]

2. Description of the Related Art For example, as shown in FIG. 9 and FIG. 10, a cross member as a chassis part of an automobile mainly comprises a tubular body 2 having a rectangular cross section.
And the collar (parts) with the upper and lower pipe walls penetrated
3 is mounted on the transmission 5 using bolts 4 through which the collar 3 is inserted.
Are combined.

Conventionally, the collar 3 is attached to the tubular body 2 by connecting the collar 3 from an upper hole 6 formed in an upper tube wall of the tubular body 2 to a lower hole 7 formed in a lower tube wall thereof. After the insertion, a method of welding all corners of the corners 8 and 9 between the periphery of each hole 6 and 7 and the collar 3 was generally adopted. Here, the collar 3 has a stepped shape having a large diameter portion 3a and a small diameter portion 3b, and a step 3c between the large diameter portion 3a and the small diameter portion 3b is formed as a peripheral portion of the lower hole 7. The position is fixed while being in contact with the inner surface.

[0004]

However, according to the method of attaching the collar 3 to the tubular body 2 using the above-described welding, the tubular body 2 and the collar 3 are deformed by the heat input of welding, and the shape accuracy is reduced. There is a problem that deterioration is inevitable, and in some cases, troublesome straightening is required. In addition, since the heat-affected zone on the base material side may decrease in strength, a thick-walled tubular body 2 must be used.
This was an obstacle in reducing the weight. Further, in some cases, a rustproofing material plated with plating is used as the tubular body 2, but in this case, the plating layer evaporates due to the heat input of welding, so that a reduction in corrosion resistance is inevitable.
There was also a problem.

Japanese Patent Application Laid-Open No. 6-198358 discloses that the wall of a tubular body is radially expanded by hydraulic pressure and is pressed into the wall integrally with a punch and an insert (part) fitted to the punch. A method is described in which a hole is opened while a part of the wall portion is bulged inward, and the bulged portion is pressed against the insert. In such a method, a high-pressure hydraulic pressure is applied from the beginning. Therefore, there is a risk that the periphery of the hole may burst at the same time when the hole is opened, and it is difficult to stably mount the hole.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for securely attaching a component to a tubular body without welding.

[0007]

In order to achieve the above object, the present invention provides a method for punching a hole by applying a punch to the wall of a tubular body while introducing a relatively low-pressure liquid into the tubular body. A first step of expanding a peripheral portion of the hole into the inside of the tubular body, a second step of press-fitting a component into the hole of the tubular body, and introducing a relatively high-pressure liquid into the inside of the tubular body to form the hole. And a third step of pushing back the bulged portion of the peripheral portion by hydraulic pressure and tightening and fixing the component in the hole.

[0008] In the method of attaching parts to the tubular body as described above, when a hole is formed in the tubular body, the pressure of the liquid introduced into the tubular body is adjusted so that an appropriate amount of the peripheral portion of the hole is formed in the tubular body. Can swell inside the body and then
When a high-pressure liquid is introduced into the tubular body by press-fitting the component into the hole, the bulging portion is pushed back by the liquid pressure, and the component is tightened and fixed in the hole with an appropriate force.

According to the present invention, in the first step, two opposing holes are formed in the tube wall of the tubular body, and in the second step, one shaft-like component is inserted into the two holes. It may be. In the case where the shaft-like component has a stepped shape, when the shaft-like component is press-fitted into the two holes in the two steps, the bulging portion of the peripheral portion of one of the holes is machined at the step of the component. Alternatively, the component may be pushed back, and the part may be tightened and fixed in the one hole.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 to FIG. 5 show one embodiment of the present invention. In the present embodiment, a stepped collar (part) 3 is attached to a tubular body 2 as the cross member 1, and a relatively low-pressure liquid 1 is provided inside the tubular body 2.
0, and two punches 1 on the upper and lower pipe walls.
At the same time as opening holes 13 and 14 by applying 1, 12
A hole forming step (FIG. 1) for expanding peripheral portions of the holes 13 and 14 into the inside of the tubular body, an inserting step of press-fitting the collar 3 into the holes 13 and 14 of the tubular body 2 (FIG. 2), A mechanical caulking step (FIG. 3) for tightening and fixing the distal small-diameter portion 3b of the collar 3 into the hole 14 in the lower tube wall of the collar 2; The hydraulic pressure caulking step (FIGS. 4 and 5) for tightening and fixing the large-diameter portion 3a of the collar 3 in the hole 13 of the wall is schematically configured.

In the hole punching step, as shown in FIG. 1, of the two punches, an upper die 15 provided with an upper punch (large-diameter punch) 11 and a lower punch (small-diameter punch) 12 are provided. The tubular body 2 between the lower mold 16 and
The large-diameter punch 11 is introduced into the tubular body 2 while introducing a liquid 10 at a high pressure, for example, about 70 MPa (about 700 atmospheres).
And the small-diameter punch 12 are advanced by driving means (not shown). Then, since the liquid pressure is applied to the inside of the tubular body 2, the portions of the upper and lower pipe walls that come into contact with the punches 11 and 12 and the surrounding portions bulge inward in a truncated cone shape,
Eventually, the holes 13 and 14 are opened in the truncated conical portion, and at the same time, conical bulging portions 17 and 18 are formed on the periphery of the holes 13 and 14. After the completion of the drilling, the tubular body 2
The liquid 10 is drained from the inside of the
And the mold is opened, whereby the hole making step is completed. The punch diameter of each of the large-diameter punch 11 and the small-diameter punch 12 is set to be substantially the same as that of the large-diameter portion 3a and the small-diameter portion 3b of the collar 3.
Holes 13 and 14 having substantially the same diameter as the large diameter portion 3a and the small diameter portion 3b of the collar 3 are respectively formed in the lower tube wall.

In the insertion step, as shown in FIG.
The tubular body 2 having been bored is set on a jig 20 with its lower tube wall facing downward. The jig 20 is formed with a concave hole 21 that matches the lower hole (small-diameter hole) 14.
And the jig 20 so that the tubular body 2 is aligned with the concave hole 21.
Position on top. And then, stepped collar 3
Into the tubular body 2 from the upper hole (large diameter hole) 13,
First, the large-diameter portion 3a is pressed into the large-diameter hole 13, and the collar 3 is further pushed into the tubular body 2, and the small-diameter portion 3b is pressed into the lower small-diameter hole 14, whereby the insertion process is performed. Ends.

The mechanical caulking process is performed subsequent to the above-described insertion process, and the small-diameter portion 3b of the collar 3 is inserted into the lower small-diameter hole 14b.
After that, the collar 3 is further pushed into the tubular body 2 as it is. Then, as shown in FIG. 3, the bulging portion 18 (FIG. 2) at the peripheral edge of the lower small-diameter hole 14 is mechanically pushed back to the original flat state by the step 3c of the collar 3, and as a result, The small-diameter portion 3b of the collar 3 is tightened and fixed in the small-diameter hole 14, and the sub-assembly body 22 in which the collar 3 is temporarily attached to the tubular body 2 is completed.

In the hydraulic caulking process, as shown in FIGS. 4 and 5, the sub-assembly body 22 after the mechanical caulking process is restrained between the upper and lower dies 25 and 26 for hydraulic caulking. . At this time, the large-diameter portion 3a and the small-diameter portion 3b of the collar 3 protruding from the tubular body 2 are placed in the recessed holes 25a, 26a provided in the upper mold 25 and the lower mold 26, respectively, with the bottom thereof. 22 is liquid-tightly constrained from outside (FIG. 4). Then, in this state, FIG.
As shown in the figure, an ultra-high pressure in the tubular body 2, for example, 200
A liquid 10 of about MPa (2000 atm) is introduced. Then, the bulging portion 17 at the peripheral edge of the upper large-diameter hole 13 (FIG. 4)
Is returned to the original flat state by the hydraulic pressure. As a result, the large-diameter portion 3a of the collar 3 is tightened and fixed in the large-diameter hole 13, whereby the collar 3 is attached to the tubular body 2 at two upper and lower positions. The cross member 1 (FIG. 9) tightened and fixed in the holes 13 and 14 is completed.

The step 3c of the collar 3 is shown in FIG.
7, as shown in FIG. 7, the outer peripheral edge 3d may be formed in, for example, a conical shape so as to protrude toward the small diameter portion 3b at an acute angle. In this case, the insertion step (FIG. 6) and the mechanical crimping step (FIG. During the transition to FIG.
The outer peripheral edge 3d bites into the bulge 18 at the peripheral edge of the collar 3 to generate a greater tightening force, so that the small diameter portion 3b of the collar 3 is tightly fixed in the small diameter hole 14.

Here, when a straight collar 30 as shown in FIG. 8 is attached to the tubular body 2 in place of the stepped collar 3, the upper and lower pipes of the tubular body 2 are required in the hole making step. Holes 13 and 14 of the same diameter are opened in the wall, and in the insertion step, the collar 30 is press-fitted into these holes 13 and 14 to omit the mechanical caulking step, and then follow the hydraulic caulking step of the above embodiment. A hydraulic swaging step is performed. FIG. 8 shows the hydraulic pressure caulking process. In this case, the ultrahigh pressure hydraulic pressure acts on the bulging portions 17 and 18 (FIG. 1) at the peripheral edges of the holes 13 and 14, and both of them are pressed. It is pushed back to its original flat state, and as a result, the collar 30 is simultaneously clamped in the upper and lower holes 13 and 14.

In each of the above embodiments, the hollow stepped collar 3 or the straight collar 30 is used as a component to be attached to the tubular body 2. However, the type of this attachment component is arbitrary and a solid It may be a shaft-shaped part or a deformed part having a short shaft part. When attaching a deformed part having a short shaft portion to the tubular body 2, the hole may be formed while forming a bulging portion at one place on the tube wall of the tubular body 2 in the hole forming step (FIG. 1). Good.

[0019]

As described above, according to the method for attaching components to a tubular body according to the present invention, since the component is not affected by heat as in the case of welding, not only thermal deformation but also a decrease in base material strength is obtained. Can be prevented beforehand, which greatly contributes to the improvement of the shape accuracy and the reduction in thickness and weight, and furthermore, the stable use of the rust preventive material is also possible, and the applicable range is expanded. Further, in the hole making step, since a relatively low pressure hydraulic pressure is applied, the hole making and the formation of the bulging portion around the hole can be stably performed,
Stable manufacturability can be established.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a hole making step in one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a step of inserting a stepped collar in the present embodiment.

FIG. 3 is a cross-sectional view showing a mechanical caulking step in the present embodiment.

FIG. 4 is a cross-sectional view showing an initial stage of a hydraulic caulking process in the present embodiment.

FIG. 5 is a cross-sectional view showing a final stage of a hydraulic caulking process in the present embodiment.

FIG. 6 is a cross-sectional view showing a step of inserting a stepped collar partially changed in shape.

FIG. 7 is a cross-sectional view showing a step of mechanically caulking a stepped collar partially changed in shape.

FIG. 8 is a cross-sectional view illustrating a hydraulic caulking process according to another embodiment of the present invention.

FIG. 9 is a perspective view showing an external shape of a cross member for an automobile, which is an example to which the present invention is applied.

FIG. 10 is a cross-sectional view showing a structure for attaching a collar to a tubular body constituting a cross member.

[Explanation of symbols]

 Reference Signs List 2 tubular body 3 collar (part) 3c step of part 3d outer peripheral edge of step 10 liquid 11, 12 punch 13, 14 hole 15, 16 hole forming die 17, 18 bulging part 20 jig for insertion and machine swaging 25, 26 Hydraulic caulking type

Claims (3)

[Claims] 1. A first method in which a relatively low-pressure liquid is introduced into a tubular body while a hole is made by applying a punch to the tube wall, and a peripheral portion of the hole is swelled into the tubular body. A second step of press-fitting a part into the hole of the tubular body, and introducing a relatively high-pressure liquid into the inside of the tubular body to push back a bulged portion of a peripheral portion of the hole by hydraulic pressure, And a third step of tightening and fixing the component inside the component. 2. The method according to claim 1, wherein in the first step, two opposing holes are formed in the tube wall of the tubular body, and in the second step, one axial component is press-fitted into the two holes. Item 1. The component mounting method according to Item 1. 3. The shaft-shaped part has a stepped shape, and when the shaft-shaped part is press-fitted into two holes in the second step, the bulging part of the peripheral edge of one hole is machined at the step of the part. The component mounting method according to claim 2, wherein the component is pushed back and the component is tightened and fixed in the one hole.