JP3187805B1 - Pipe dent processing method - Google Patents

Abstract

Abstract: [Problem] A burr is not generated in the vicinity of a concave portion of a pipe, a press device can be reduced in size, the durability of a cored bar can be increased, a work of separating a cored bar from a pipe after punching can be smoothly performed, and mass production can be achieved. Provided is a method of processing a pipe dent suitable for a pipe. SOLUTION: In a portion of a pipe 17 facing recesses 13a to 13d of a cored bar 13, recesses 17a to 1 of the pipe 17 are provided.
Punching is performed while leaving a gap between 7d and the recesses 13a to 13d of the metal core 13. As a result, the durability of the mandrel 13 is enhanced, and the work of separating the mandrel 13 and the pipe 17 is facilitated. A processing method corresponding to mass production can be obtained. At this time,
The concave processing of the pipe 17 is a shearing processing. Therefore, a small pressing pressure is sufficient, the size of the pressing device is reduced, and burrs are not generated near the concave portions 17a to 17d of the pipe 17 during processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe dent processing method, and more particularly, to a pipe dent processing method suitable for mass production, in which the durability of a metal core is enhanced and burrs are not generated in a concave portion of the pipe.

[0002]

2. Description of the Related Art A headrest, which is adjustable in height and supports the head of an occupant from behind, is mounted above a driver's seat and a passenger's seat. The headrest mainly has a cushion body against which the occupant's head is pressed, and a substantially U-shaped headrest stay for inserting the cushion body into a seat. At the end of the headrest stay, several recesses are formed at a predetermined pitch in the stay axis direction. The headrest is attached to the seat by hooking a hook in the upper part of the seat in any of these recesses.

[0003] As a method of forming a dent in a headrest stay, for example, a "method of forming a dent in a pipe" described in Japanese Patent No. 2974049 is known. According to this conventional method, a core is first inserted into a pipe. Several concave portions are formed on the outer peripheral surface of the core metal in the axial direction. Each recess is communicated with one end of several outer circumferential grooves engraved along the circumferential direction of the core metal, and the other end of each outer circumferential groove is a cross section engraved on the core metal over the entire length of its axis. It communicates with the arc-shaped vertical groove. The vertical groove is displaced by 90 degrees with respect to each recess on the outer peripheral surface of the cored bar. Next, the pipe into which the metal core has been inserted is sandwiched between the upper mold and the lower mold to be firmly fixed. Next, as shown in an explanatory view of the pipe dent processing method according to the conventional means in FIG.
A punch 103 for forming a concave portion is punched from the outside onto a portion of the pipe 102 facing each concave portion 101 of the metal core 100. As a result, each portion of the punched pipe 102 is plastically deformed into the shape of the corresponding concave portion 101 of the metal core 100, and several concave portions 104 appear at predetermined positions on the outer peripheral surface of the pipe 102.

Next, the core bar 100 is pulled out of the pipe 102. Specifically, first, the cored bar 100 is rotated around its axis. Each outer peripheral groove (not shown) is engraved on the outer peripheral surface of the cored bar 100. Therefore, pipe 102
The recesses 104 do not come into contact with the outer peripheral surface of the metal core 100 to hinder the rotation of the metal core 100. Next, when the core metal 100 is rotated to a position where each concave portion 104 of the pipe 102 is housed in a vertical groove (not shown), the core metal 100 is rotated.
Is pulled in the axial direction to remove the core metal 10 from the pipe 102.
Extract 0. Then, the upper mold 105 and the lower mold (not shown) are opened, and the pipe 102 is removed.

[0005]

However, this conventional method for forming a concave portion of a pipe has the following problems. That is, the conventional dent process is a die forging process in which the concave portion 104 (the inner wall surface) of the pipe 102 is hit against the concave portion 101 (the bottom wall surface) of the metal core 100. For this reason, burrs were likely to occur near the concave portion 104 in the processed pipe 102. Moreover, at the time of punching, the core metal 10
A large external force acts on the metal core 100, and the metal core 100 is damaged in a short period of time due to, for example, metal fatigue, and the durability of the metal core 100 is reduced. Further, in such a die forging process, at the time of punching, the concave portion 104 of the pipe 102 is easily brought into close contact (adhesion) with the concave portion 101 of the metal core 100, and
In many cases, it was not possible to perform the work of rotating the 0 and pulling it out. Therefore, this conventional method is not suitable for actual mass production. Further, the punching according to the conventional method is performed by die forging with plastic deformation of the pipe 102. In order to perform die forging, it is necessary to apply a large external force. For this reason, a large-sized press device must be employed as the dent processing equipment, and there is a problem that the equipment cost increases.

The inventor of the present invention, as a result of long-term intensive research, has found that if the pipe recesses are punched with a gap between them so that they do not come into contact with the outer wall of the core bar, only the shape of the recesses is reduced. This is a shearing process in which the volume does not change, and as a result, burrs do not occur near the recess of the processed pipe, the external force at the time of punching is small, and the pressing device can be downsized and the durability of the core metal It has also been found that the concave portion of the pipe does not adhere to the bottom wall surface of the concave portion of the metal core at the time of punching, so that the work of separating the metal core from the pipe is smooth, and the processing method is suitable for mass production. Completed.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the occurrence of burrs in the vicinity of a concave portion of a processed pipe, reduce the size of a press device, increase the durability of a cored bar, and separate the cored bar from a pipe after punching. It is an object of the present invention to provide a pipe dent machining method capable of smoothly performing the above-mentioned process, thereby realizing mass production.

[0008]

According to the first aspect of the present invention, a punch is punched from the outside of a pipe into a portion of a pipe in which a metal core having a concave portion on an outer peripheral surface is inserted, the portion facing the concave portion. a recess by shearing, then encounters depressions processing method of a pipe of separating the core metal and the pipe
When the above punching, in the punching direction,
This is a pipe dent processing method for producing a gap between the concave part of the pipe and the concave part of the metal core . The material of the core is not limited. For example, various metals such as stainless steel, which has high durability and is not easily deformed, can be used. Further, the core metal may be a solid body or a cylindrical body. The shape, the number, and the position of the concave portions of the cored bar are not limited. The material of the pipe to be recessed is not limited. For example, various metals such as iron, aluminum, and brass can be used.

[0009] The shape and number of the recesses formed in the pipe are not limited. Usually, it is the shape and the number of the concave portions of the cored bar. The separation between the cored bar and the pipe may be performed by moving the cored bar or the pipe. Alternatively, both may be moved in opposite directions. At this time, it is not always necessary to rotate the cored bar and / or the pipe around their respective axes as in claim 2. For example, if the cored bar is of an assembling type that can be divided into a plurality in the radial direction, the cored bar can be partially extracted from the pipe after punching. The punch stroke amount during punching is not limited. The point is that it is sufficient that a gap can be formed between the concave portion of the pipe and the concave portion of the metal core in the punching direction. Further, the length of the gap is not limited. It is sufficient if there is a gap even slightly.

According to a second aspect of the present invention, in addition to the concave portion, the outer peripheral surface of the cored bar communicates with the concave portion so as to be centered on the pipe axis of the concave portion of the pipe. An outer circumferential groove extending in the circumferential direction of the core metal, which allows rotation, and communicating with this outer circumferential groove, allowing the concave portion of the pipe to relatively move in the axial direction, in the axial direction of the core metal. When the core and the pipe are separated from each other, the core and / or the pipe are rotated around their respective axes, so that the concave portion of the pipe is formed into a vertical groove through the outer peripheral groove. Disposing the cored bar and the pipe while moving the cored bar and / or the pipe in their respective axial directions by using the vertical groove as a groove for inserting a concave portion of the pipe. 2. A method for processing a dent of a pipe according to (1). The groove shape of the outer peripheral groove is not limited. For example, a groove having a rectangular cross section or a groove having a semicircular cross section may be used. Also, the length of the groove is not limited. In short, any length is acceptable as long as the recess and the vertical groove of the cored bar can communicate with each other. The formation position of the vertical groove on the outer peripheral surface of the core metal is not limited. However, it is preferable that the position is shifted by 60 to 120 degrees with respect to each recess.
Within this range, a large pressing pressure at the time of punching can be firmly received by the portion of the core bar opposite to the concave portion. Further, the cross-sectional shape of the vertical groove is not limited. For example, the shape may be a circular arc or a rectangular cross section.

The length of the longitudinal groove of the cored bar is not limited. Normal,
It is the length from the concave part to the tip of the cored bar. As for the rotation of the concave portion of the pipe, the core metal may be rotated, or the pipe may be rotated. Also, both of them may be used. For the movement of the concave portion of the pipe, the core metal may be moved, or the pipe may be moved. Of course, both may be used.

Further, the invention according to claim 3 is the method according to claim 1 or 2, wherein the punching is carried out after the pipe is sandwiched and fixed between an upper mold and a lower mold in advance. is there.

[0013]

According to the present invention, a punch is punched from the outside into a portion of a pipe in which a core having a concave portion formed on the outer peripheral surface is inserted, the portion facing the concave portion. At this time, punching is performed with a gap in the punching direction so that the concave portion of the pipe does not contact the concave portion of the metal core. As a result, the recess of the pipe is formed by shearing. This allows
The recess can be formed with a smaller external force than the conventional die forging. Therefore, the size of the press device can be reduced, and the equipment cost can be reduced. In addition, the durability of the metal core is increased, and no burrs are generated near the concave portion of the processed pipe. Further, at the time of punching, a gap is formed in the punching direction between the concave portion of the pipe and the concave portion of the metal core, so that the opposing surfaces of the two concave portions do not adhere to each other as in the conventional method. Therefore, the work of separating the cored bar and the pipe can be performed smoothly. Thus, in the conventional method, during the actual dent processing, the work of removing the closely-contacted concave parts must be frequently performed, and in reality, the pipe dent processing method could not be automated, but in the present invention, , This automation can be realized.

In particular, according to the second aspect of the present invention, when the core is separated from the pipe, the core is rotated about its axis or the pipe is rotated about its axis. Alternatively, by rotating the metal core and the pipe in opposite directions about each axis, the concave portion of the pipe is arranged in the vertical groove through the outer peripheral groove. Then, using the vertical groove as a groove for insertion of the concave part of the pipe, the core metal is moved in the axial direction, the pipe is moved in the axial direction, or the core metal and the pipe are opposite to each other in the axial direction. Separate the mandrel from the pipe while moving it. Thereby, the separating work between the cored bar and the pipe after punching can be actually performed smoothly.

According to the third aspect of the present invention, punching is performed after the pipe is firmly sandwiched by the upper mold and the lower mold, so that the pipe shake due to a large impact at the time of punching can be suppressed. . As a result, punching can be performed at an accurate position on the outer peripheral surface of the pipe.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. For convenience of description, the front-rear direction of the apparatus is defined as an X direction, the width direction is defined as a Y direction, and the height direction is defined as a Z direction. FIG. 1 is a cross-sectional view showing each step of a pipe dent processing method according to one embodiment of the present invention. FIG. 2 is a side view including a partial cross-sectional view of a pipe dent processing apparatus used in the pipe dent processing method according to one embodiment of the present invention.
FIG. 3 is a front view of a main part of a pipe dent processing apparatus used in the pipe dent processing method according to one embodiment of the present invention. FIG. 4 is an enlarged perspective view of a main part showing a punching step of the pipe dent processing method according to one embodiment of the present invention.

2 and 3, reference numeral 10 denotes a pipe dent processing apparatus used in a pipe dent processing method according to an embodiment of the present invention.
Is a base plate 11 that is long in the X direction, a lower mold 12 mounted on the base plate 11,
And a rotating cylinder 14 long in the Y direction for rotating the core 13 about an axis.
An upper die 15 disposed above the lower die 12 and fitted on the upper surface of the lower die 12; a pressing plate 16 for punching disposed above the upper die 15; Four punches 18A to 18D for punching four recesses 17a to 17d (see FIG. 1) in a pipe 17 externally inserted into the cored bar 13 by penetrating the upper and lower surfaces of the portion.
And Hereinafter, these components will be described in detail.

The lower mold 12 is formed one step higher from the rear end to the center. A lower fitting groove 1 having a semicircular cross section that is long in the X direction is formed in an intermediate portion of the upper surface of the raised portion in the Y direction.
9A are formed. The front end 12a of the lower mold 12 is bent upward. The base of the metal core 13 is horizontally supported at the center of the front end 12 a via a bush 20. Only the lower part of the metal core 13 is housed in the lower fitting groove 19A with a gap having substantially the same width as the thickness of the pipe 17 between the core metal 13 and the inner peripheral surface of the groove forming part. The upper fitting groove 19B facing the lower mold fitting groove 19A is formed in the lower surface of the upper mold 15 at an intermediate portion in the Y direction. The end of the metal core 13 on the base side is disposed forward of the front end 12a. One end of a plate-like rotating arm 21 is pivotally supported by this portion.
On the other hand, the other end of the rotating arm 21 is pivotally supported by the tip of a rod 14 a of the rotating cylinder 14. The base of the rotary cylinder 14 is pivotally supported by a base plate 11 via a bracket (not shown) so as to be swingable in a vertical plane in the Y direction. Therefore, when the rod 14a of the rotary cylinder 14 is moved in and out, the cored bar 13 is moved in the Y direction by 100 degrees about the axis thereof via the rotary arm 21 while swinging the rotary cylinder 14. Rotates in a vertical plane.

As shown in FIG. 1, FIG. 2 and FIG.
Four recesses 13a to 13d are formed at predetermined intervals in the axial direction in the upper part of the outer peripheral surface of the front end of the recess.
Also, on the outer peripheral surface of the metal core 13, these concave portions 13a are provided.
13d, the outer peripheral grooves 131a to 131d extending in the circumferential direction of the metal core 13, and these outer peripheral grooves 131a.
A vertical groove 13e extending in the axial direction of the metal core 13 is formed so as to communicate with. Each outer peripheral groove 131a-13
1d is a short groove curved into an arc shape that allows relative movement in the axial direction of the concave portions 17a to 17d appearing in the pipe 17 by punching. In addition, the vertical groove 13e
Is a long groove having a crescent-shaped cross section formed over substantially the entire length of the cored bar 13 to allow relative rotation of each of the recesses 17a to 17d around the pipe axis. This vertical groove 13
e is displaced in the circumferential direction by 100 degrees with respect to each of the recesses 13a to 13d on the outer peripheral surface of the cored bar 13.

At the front of the upper die 15, a depression 15a is formed in an area facing the four punches 18A to 18D. The bottoms of the depressions 15a penetrate the upper and lower surfaces (the lower surface is the surface on which the upper fitting groove 19B is formed), and the thinned tips 18a to 18d of the four punches 18A to 18D are formed.
Holes 1 for accommodating each of them so as to be movable in the Z direction.
5b are formed. Upper surface of upper die 15 and pressing plate 1
6, a plurality of coil springs 22 are arranged. Normally, the distal ends 18a to 18d of the punches 18A to 18D are housed in the corresponding holes 15b by the spring force of each coil spring 22. However, at the time of punching, the pressure plate 16 is pushed down by an external force of a hydraulic cylinder (not shown). Accordingly, the tip portions 18a to 1D of the punches 18A to 18D are opposed to the spring force of each coil spring 22.
8d protrudes from the corresponding holes 15b into the upper fitting groove 19B.

Next, with reference to FIG. 1, a description will be given of a pipe dent processing method by the pipe dent processing device 10. FIG. First, the pipe 17 is extrapolated to the metal core 13 using the lower fitting groove 19A as a guide (FIGS. 1A and 1A1). Next, the rod of the hydraulic cylinder (not shown) is protruded downward, and the upper die 15 is lowered to fit the lower die 12. Thereby, the lower fitting groove 19A and the upper fitting groove 19B overlap to form a fitting hole of the pipe 17. Thus, the pipe 17 is firmly sandwiched and fixed between the lower mold 12 and the upper mold 15 (FIGS. 1B and 1B1). as a result,
Shaking of the pipe 17 due to a large impact at the time of punching can be suppressed. Therefore, punching can be performed at an accurate position above the pipe 17.

Subsequently, when the rod of the hydraulic cylinder is further projected downward, the pressure plate 16 is lowered against the spring force of the coil spring 22. Thereby, each punch 18A-1
8D protrude into the upper fitting groove 19B. In this way, using the corresponding recesses 13a to 13d as formation guides, the four recesses 17a
１７17d are punched. At this time, each recess 17a-
17d and the corresponding recesses 13a to 13 of the metal core 13.
A gap C is provided between each of the concave portions d so as not to contact the corresponding concave portions (FIGS. 1 (c) and 1 (c1)).

Thus, the recesses 17a to 17 of the pipe 17
d is formed by a shearing process that requires less external force than a conventional die forging process. As a result, the size of the press device can be reduced, and the equipment cost can be reduced. Moreover, since the external force at the time of punching received by the metal core 13 is smaller than that of the related art, the durability of the metal core 13 is enhanced. Further, since it is not a die forging process, each of the recesses 17a to 17d after the process is performed.
No burrs are generated in the vicinity. Thus, the corresponding recesses 17 a to 17 d of the pipe 17 and the recesses 13 a to 13
Since the gap C is formed between the two concave portions, the two concave portions do not adhere to each other. Thereby, the work of extracting the metal core 13 can be facilitated. For this reason, in the conventional method, it is necessary to remove the recesses that are in close contact with each other, so that it is impossible to visibly mass-produce the recessed pipe 17. Are not in close contact with each other, so that the dent processing can be automated, and the pipe 17 having the dent can be practically mass-produced.

Next, by the operation of the rotary cylinder 14,
The mandrel 13 is rotated by 100 degrees about the axis.
Then, the concave portions 17a to 17d of the pipe 17 are disposed inside the vertical groove 13e through the corresponding outer peripheral grooves 131a to 131d (FIGS. 1 (d) and 1 (d)).
1)). At this time, the outer peripheral groove 13
1a to 131d are engraved. Therefore, the recesses 17a to 17d do not come into contact with the outer peripheral surface of the metal core 13 and hinder the rotation of the metal core 13. At this time, the punches 18A to 18D are kept pressed down. Subsequently, when the rod of the hydraulic cylinder (not shown) is pulled up, the punches 18 </ b> A to 18 </ b> D are pushed back by the spring force of the coil springs 22. At the same time, the upper die 15 and the pressure plate 16 are pulled up and opened (FIGS. 1 (e) and 1 (e1)). After that, the pipe 17 is pulled out from the metal core 13 (FIG. 1F).

[0025]

According to the present invention, a portion of the pipe facing the concave portion of the metal core is punched with a gap in the punching direction so that the concave portion of the pipe does not contact the concave portion of the metal core. As a result, the durability of the mandrel is enhanced, and the work of separating the mandrel and the pipe can be performed smoothly.
The dent processing can be automated. Further, since the dent processing of the pipe is a shearing processing, the processing can be performed with a small press pressure. Further, the durability of the metal core is enhanced, and no burrs are generated near the recessed portion of the processed pipe.

In particular, according to the second aspect of the present invention, since the outer peripheral groove and the vertical groove are formed on the outer peripheral surface of the metal core in addition to the concave portion, the separating work between the metal core and the pipe after the punching is performed smoothly. Can be done.

According to the third aspect of the present invention, at the time of punching, the pipe is firmly sandwiched between the upper mold and the lower mold, and punching is performed. The recess can be punched at an accurate position on the outer peripheral surface.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view taken along a plane including a pipe axis, showing a process of inserting a pipe into a cored bar in a pipe dent processing method according to an embodiment of the present invention. (A1) It is sectional drawing along the surface orthogonal to the pipe axis which shows the process of inserting the pipe into the metal core of the pipe dent processing method concerning one Example of this invention. (B) It is sectional drawing along the plane containing the pipe axis which shows the metal mold | die fitting process of the pipe dent processing method concerning one Example of this invention. (B1) It is sectional drawing along the surface orthogonal to the pipe axis which shows the metal mold | die fitting process of the dent processing method of the pipe which concerns on one Example of this invention. (C) It is sectional drawing along the surface containing the pipe axis which shows the punching process of the pipe dent processing method concerning one Example of this invention. (C1) It is sectional drawing along the surface orthogonal to the pipe axis which shows the punching process of the pipe dent processing method concerning one Example of this invention. (C2) A partially enlarged view of FIG. 1 (c). (D) It is sectional drawing along the surface containing the pipe axis which shows the core metal rotation process of the pipe dent processing method concerning one Example of this invention. (D1) It is sectional drawing along the surface orthogonal to the pipe axis which shows the core metal rotation process of the dent processing method of the pipe which concerns on one Example of this invention. (E) It is sectional drawing along the plane containing the pipe axis which shows the metal mold | die opening process of the pipe dent processing method concerning one Example of this invention. (E1) It is sectional drawing along the surface orthogonal to the pipe axis which shows the metal mold | die opening process of the dent processing method of the pipe which concerns on one Example of this invention. (F) It is sectional drawing along the plane containing the pipe axis which shows the pipe extraction process of the pipe dent processing method concerning one Example of this invention.

FIG. 2 is a side view including a partial cross-sectional view of a pipe dent processing apparatus used in the pipe dent processing method according to one embodiment of the present invention.

FIG. 3 is a front view of a main part of a pipe dent processing apparatus used in the pipe dent processing method according to one embodiment of the present invention.

FIG. 4 is an enlarged perspective view of a main part showing a punching step of the pipe dent processing method according to one embodiment of the present invention.

FIG. 5 is an explanatory diagram of a method of processing a pipe dent according to a conventional means.

[Explanation of symbols]

 10 Pipe dent processing device, 12 Lower mold, 13 Core, 13a to 13d recess, 131a to 131d Outer circumferential groove, 13e Vertical groove, 17 Pipe, 17a to 17d recess, 18A to 18D Punch, C gap.

Claims (3)

(57) [Claims] 1. A concave part is formed by punching a portion of a pipe in which a metal core having a concave part on an outer peripheral surface is inserted into a part facing the concave part by punching from the outside of the pipe and performing a shearing process. A method of processing a pipe dent for separating a cored bar and a pipe , wherein the punching is performed in the punching direction,
A pipe dent processing method for producing a gap between a concave part of a pipe and a concave part of a metal core . 2. An outer peripheral surface of the core metal, in addition to the concave portion, communicates with the concave portion to allow relative rotation of the concave portion of the pipe around a pipe axis. An outer circumferential groove extending in the circumferential direction, and a longitudinal groove extending in the axial direction of the cored bar communicating with the outer circumferential groove and allowing the concave portion of the pipe to relatively move in the axial direction; At the time of separation of the core bar and the pipe, by rotating the core bar and / or the pipe around each axis, the concave portion of the pipe is arranged in the vertical groove through the outer peripheral groove,
2. The method according to claim 1, wherein the vertical groove is used as a groove for inserting a concave portion of the pipe, and the core metal and the pipe are separated from each other while moving the core metal and / or the pipe in the respective axial directions. Pipe dent processing method. 3. The method according to claim 1, wherein the punching is performed after the pipe is sandwiched and fixed between an upper mold and a lower mold in advance.