JPH08164437A - Serration forming device of tube - Google Patents

Abstract

PURPOSE: To improve the quality of products by reducing forming load at one process pressing as much as possible. CONSTITUTION: A device has a die hole 11 formed in the lower die side with the reduced diameter of its tip part 111 and a tube extruding member 3, which executes swaging by abutting on a holder 5 of upper die side and pushing a tube P inserted in die hole 11 into the tip part 111. A guide bolt 61 is vertically arranged at the tip of punch 51 provided in the holder 5, a serration die 2 is movably arranged along the guide bolt and a spring member 62 is arranged to support the serration die 2. The serration die 2 is brought into pressed contact with the inner peripheral face of the tube P to be swaged and is moved following the rolling extension of the inner peripheral face of tube P, thus executing serration forming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serration processing apparatus for pipe materials, and more particularly to a serration processing apparatus that significantly reduces the pressure load during press working.

[0002]

2. Description of the Related Art As an apparatus for manufacturing a pipe material P having serrations P1 on the inner periphery of a half as shown in FIG. 8, the applicant previously proposed a serration processing apparatus shown in FIG. 9 ( Japanese Patent Application No. 6-1333). In the drawing, the die hole 11 of the die 1 has a diameter of a tip portion (lower end portion) 111 reduced to a predetermined amount, a pipe material P is inserted in a large diameter general portion, and a pipe material pushing member 3 is provided on an upper end surface thereof. The pushing part 32 of is in contact. The substrate 31 of the pipe member pushing member 3 is fitted into the guide post 41, and the lower surface thereof is supported by the coil spring 42. A lower end surface of a columnar holder 5 provided in an upper mold (not shown) is brought into contact with the upper surface of the substrate 31, and a small-diameter columnar punch 51 projecting at the center of the lower end surface is used to push the pushing portion 3
It has entered the pipe material P through the inside of the cylinder 2. A columnar serration die 2 is fixed to the tip of the punch 51.

In such a serration processing apparatus, when the upper die is lowered, the punch 51 integrated with the holder 5 and the serration die 2 are lowered, and the holder 5 pushes the pushing portion 32 of the pipe material pushing member 3 to lower, The pipe material P moves in the die cavity 11 of the die 1 toward the tip portion 111.
At this time, the serration type 2 also descends at almost the same speed.
When the pipe material P reaches the die hole tip portion 111 of which the diameter is reduced, the pipe end portion is bent inward and its inner peripheral surface is pressed against the outer peripheral surface of the serration die 2, and the pipe diameter is reduced to perform swaging. At the same time, the pipe wall is subjected to pressure between the outer peripheral surface of the serration die 2 and the inner peripheral surface of the die hole tip portion 111 to cause plastic deformation on the inner peripheral surface of the pipe material P in contact with the serration die 2 to perform serration processing. Done.

[0004]

In the proposed device, the serration mold moves downward at almost the same speed as the pipe material,
It has an excellent performance that pressurizing load at the time of pressing is reduced, which is not present in the previous devices, but there is a strong demand to further reduce the load during pressing.

Therefore, the present invention has been made in view of the above demands, and it is an object of the present invention to provide a pipe material serration processing apparatus in which the molding load in the one-step press molding is reduced as much as possible to improve the processing quality. To aim.

[0006]

In the first structure of the present invention, the die die hole 11 formed on the lower die side and having the diameter of the tip portion 111 narrowed, and the die die hole 11 provided on the upper die piece are provided. Hole 1
The pipe material pushing member 3 that pushes the pipe material P inserted in 1 into the tip portion 111 to perform swaging, and the pipe material P that is provided on the upper mold side and is inserted into the pipe material P and that has been swaged A serration die 2 which is pressed against the peripheral surface and is subjected to serration processing, and the serration die 2 can be moved in accordance with the rolling extension of the inner peripheral surface of the pipe P to which the outer peripheral surface thereof is pressed. It is supported on the upper mold side.

In the second structure of the present invention, a guide member 61 is provided upright at the tip of a punch 51 provided on the upper die, and the serration die 2 is provided movably along the guide member 61, and the serration die 2 is provided. A spring member 62 for urging and supporting the element in the direction opposite to the following movement direction is provided.

In the third structure of the present invention, the serration die 2 is fixed to the tip of the punch 51, the punch 51 is linearly movably held by the holder 5 provided in the upper die, and the punch 51 is also provided. Is provided with a spring member 64 for urging and supporting in a direction opposite to the following movement direction of the serration die 2.

[0009]

In the first to third constructions described above, since the serration die 2 is provided on the upper die side together with the pipe material pushing member 3, the tip portion 11 of the die die hole 11 is formed by the pipe material pushing member 3.
The serration die 2 moves at substantially the same speed as the pipe material P pushed into the inside 1. However, since the pipe wall of the pipe material P swaged in the tip portion 111 is rolled between the serration die 2 and the die die hole 11, the inner peripheral surface of the pipe material P is extended and the outer periphery of the serration die 2 is expanded. A speed difference is generated between the surface and the surface, which hinders the reduction of load during pressurization. Here, in the above configuration, the serration die 2 can move following the extension of the inner peripheral surface of the pipe material P with which the outer peripheral surface of the serration mold 2 is in pressure contact, so that the speed difference between the two is completely eliminated, and between them. The resulting frictional force is close to zero. As a result, the molding load is significantly reduced, and the shaving of the pipe material P due to the friction with the serration mold 2 is eliminated, so that the quality is improved.

[0010]

Embodiment 1 FIG. 1 shows an embodiment of the present invention, the basic structure of which is the same as that of the previously proposed device. That is, in the figure, the die 1 is provided on an unillustrated lower die, and the die cavity 11 of the die 1 has a tip portion (lower end portion) 111 whose diameter is reduced by a predetermined amount. The pipe material P is inserted in the large-diameter general portion of the mold cavity 11, and the pipe material pushing member 3 is located in contact with the upper end portion thereof. The pipe member pushing member 3 is a horizontal substrate 31.
And a pressing portion 32 having the same diameter as the pipe material P and protruding downward from the center of the substrate 31 and contacting the end surface of the pipe material P. The substrate 31 of the pipe member pushing member 3 is the guide post 4 which is erected on the lower mold.
1 is fitted at a plurality of locations on the outer circumference, and the lower surface is supported by the coil spring 42.

A lower end surface of a columnar holder 5 provided in an upper mold (not shown) is brought into contact with the upper surface of the substrate 31 of the pipe member pushing member 3, and a small diameter columnar punch 51 protruding at the center of the lower end surface is used to press the pressing portion 32. Has entered the pipe material P through the inside of the cylinder. And
A columnar serration die 2 is provided at the tip of the punch 51. A through hole 21 is provided in the center of the serration mold 2, and a guide bolt 61 is inserted into the through hole 21 from below,
Its tip is joined and fixed to the screw hole at the tip of the punch 51. The guide bolt 61 is longer than the serration die 2, and a coil spring 62 is provided between the head of the bolt and the lower surface of the serration die 2 to bring the serration die 2 into contact with the tip surface of the punch 51 as shown in the drawing. Supporting the position. The figure shows a state in which the upper mold is lowered to some extent.

The operation of the serration processing apparatus having the above structure will be described below. When the upper die is further lowered, the punch 51 and the serration die 2 which are integrated with the holder 5 are also lowered, and are pushed by the holder 5 to push the pushing portion 3 of the pipe material pushing member 3.
2 also descends (white arrow in FIG. 2). As a result, the pipe material P moves in the die hole 11 of the die 1 toward the tip portion 111 (black arrow in FIG. 2), and the serration die 2 located in the pipe material P also moves at the same speed.

When the upper die is further lowered, the pipe material P reaches the tip portion 111 of the die hole having a reduced diameter as shown in FIG. 3, the pipe end portion is bent inward, and the inner peripheral surface thereof is serrated. Press contact with the outer peripheral surface of. The pipe material P is further pushed into the die hole tip portion 111 (FIG. 4), the pipe diameter is reduced and swagenge processing is performed, and the pipe wall has an outer peripheral surface of the serration die 2 and an inner peripheral surface of the die hole tip portion 111. A pressure is detected between the inner peripheral surface of the pipe material P and the inner peripheral surface of the pipe material P that is in contact with the serration die 2 to cause plastic deformation, and serration processing is performed.

Here, since the serration die 2 and the pipe material P are moving in the same direction as a whole, the frictional force between them is relatively small, but they are sandwiched between the serration die 2 and the die hole tip portion 111. The cylinder wall of the pressed pipe material P is rolled and stretched and deformed. As a result, a speed difference is generated between the pipe wall and the serration die 2, and the frictional force increases. Here, since the serration die 2 is supported by the coil spring 62 and is movable downward, when a frictional force is generated between the serration die 2 and the inner peripheral surface of the pipe material P, the serration die 2 is so arranged that the serration die 2 cancels the frictional force.
And moves downward along the guide bolt 61 (thick black arrow in FIGS. 4 and 5). As a result, the frictional force between the serration die 2 and the pipe material P becomes almost zero, and the molding load for resisting this frictional force is greatly reduced.

The effect is shown in FIG. In the figure, the line x is according to this embodiment in which the serration type is movable, and the line y is related to the previously proposed device in which the serration type is fixed. In this embodiment, the molding load is reduced by about 10 tons as compared with the case where the serration mold is fixed.

[0016]

Embodiment 2 In FIG. 7, the serration die 2 is fixed to the tip of the punch 51 by a bolt 63 passing through the center. The punch 51 is separated from the holder 5,
A part of the upper end thereof extends into the space 5a formed in the center of the holder 5. In the extending portion of the punch 51, a tip 511 has a flat plate shape, and a coil spring 64 is disposed between the tip 511 and the bottom wall of the space 5a, and the punch 51 has an upper end surface on the lower end surface of the holder 5. It is supported in an abutting state. The other structure is the same as that of the first embodiment.

In this structure, when the upper mold is lowered,
The pipe material pushing member 3 descends via the holder 5, and the pipe material P is pushed into the die hole tip portion 111 of the die 1. With this,
As described in the embodiment, the pipe material P that is rolled and stretched,
A frictional force is generated between the serration die 2 and the serration die 2 which is in pressure contact therewith, but since the serration die 2 is supported by the coil spring 64 via the punch 51, the coil spring 64 is compressed while the friction force is eliminated. Following the expansion of the inner peripheral surface of the pipe material P, it moves downward. Thus, according to this embodiment, the same effect as that of the first embodiment can be obtained.

[0018]

As described above, according to the serration processing apparatus for a pipe material of the present invention, the forming load at the time of one-step press forming can be greatly reduced, and the galling caused by the friction between the serration die and the pipe material can be achieved. It is possible to prevent the above and also improve the quality.

[Brief description of drawings]

FIG. 1 is an overall sectional view of a serration processing apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a die-shaped hole portion showing the operation of the apparatus.

FIG. 3 is an enlarged sectional view of a die-shaped hole portion showing the operation of the apparatus.

FIG. 4 is an enlarged sectional view of a die-shaped hole portion showing the operation of the apparatus.

FIG. 5 is an enlarged sectional view of a die-shaped hole portion showing the operation of the apparatus.

FIG. 6 is a graph showing the relationship between the stroke of the tubular material pushing member and the forming load.

FIG. 7 is an overall sectional view of a serration processing apparatus according to a second embodiment of the present invention.

FIG. 8 is a cross-sectional view of a pipe material having serrations formed on the pipe end.

FIG. 9 is an overall sectional view of a conventional serration processing apparatus.

[Explanation of symbols]

 1 Die 11 Die Type Hole 111 Tip Part 2 Serration Type 3 Tubular Material Pushing Member 5 Holder 51 Punch 61 Guide Bolt (Guide Member) 62 Coil Spring (Spring Member) 64 Coil Spring (Spring Member) P Tubular Material

Claims (3)

[Claims] 1. A swaging process in which a die die hole formed on the lower die side and having a reduced diameter at the tip portion and a tube material provided on the upper die side and inserted into the die die hole are pushed into the tip portion. And a serration die which is provided on the upper die side, is inserted into the tubular material, and is pressed into contact with the inner peripheral surface of the swaged tubular material to subject it to serration processing, and A serration device for pipe material, wherein a serration die is movably supported on the upper die side so as to follow the rolling extension of the inner peripheral surface of the pipe material with which the outer peripheral surface of the serration die is pressed. 2. A guide member is provided upright on the tip of a punch provided on the upper die, the serration die is provided movably along the guide member, and the serration die is urged in a direction opposite to the following movement direction. The pipe material serration processing apparatus according to claim 1, further comprising a spring member for supporting the same. 3. The serration die is fixed to the tip of the punch, and the punch is held by a holder provided on the upper die so as to be linearly movable, and the punch is opposed to the direction of the forced operation of the serration die. The pipe material serration processing apparatus according to claim 1, further comprising a spring member that biases and supports the direction.