JPS58192625A - Pipe bending method - Google Patents

Abstract

PURPOSE:To bend-work a metallic blank pipe without causing the buckling and deformation on the pipe wall, by pinch-holding both end parts of the metallic blank pipe from the upper and lower parts by an electrode and a receiving body, heating the half face of the blank pipe by resistance heat by electrification by the electrode, and thereafter, executing its bend-working. CONSTITUTION:Both end parts of a metallic blank pipe 10 to be bend-worked are pinch-held by a fixed electrode 1, a fixed receiving body 2, a movable electrode 5 and a movable receiving body 6. Subsequently, electric power is supplied between two electrodes 1, 5, and an upper side 10b where the electrodes 1, 5 of the metallic blank pipe 10 exist is heated and softened by a resistance. In this state, the rear end part of the blank pipe 10 is pushed forward by a pushing body 9, and also the movable electrode 5 and the movable receiving body 6 are turned downwards. The blank pipe 10 is bent, also the upper part 10b which is softened following the bending lengthens in the axial direction, the upper end part of an inclined rear end face 10a is pushed in the axial direction by the pushing body 9, a material component is supplied to the lengthened part, this part does not become thin nor flat, and an excellent curved part is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tube bending method that can minimize buckling and deformation of tube walls.

Hereinafter, the present invention will be specifically explained using an example in which a relatively thin-walled pipe is bent.

When a thin-walled metal pipe is bent, the inner part, which has a small curvature, usually buckles, and the cross-sectional shape of the outer part is significantly distorted, but the illustrated embodiment prevents such buckling and deformation. It was made so that it could be done.

In FIG. 1, fl) (2) is a fixed electrode and a fixed receiver that form a pair vertically and are fixedly held in a fixed position,
A semicircular concave portion (3H4) having a slightly larger diameter than the circular blank pipe oO) to be processed is formed on the opposing surface, and there is a space between the two so that they do not come into contact with each other.
A slight gap is provided.

(5H6) is located in front of the fixed electrode (1) and the fixed receiver (2), forming a vertical pair, and is integrally held by an appropriate holding device (not shown) to obtain a desired curvature. A movable electrode and a movable receiver are rotated downward with a force (8), and on their opposing surfaces there is a semicircular recess (force (8) ,
A slight gap is provided between the two to prevent them from coming into contact with each other.

The rear end surface (+Oa) of the raw pipe 00) is
It is formed into an inclined surface with a protruding upper part.

To bend, first press the front end of the raw pipe QO) between the movable electrode (5) and the movable receiver (6) so that it does not move, and then press the front end of the raw pipe QO) slightly forward of the rear end of the raw pipe 00). The part is supported slidably in the axial direction by a fixed electrode (1) and a fixed receiver (2).

Next, the upper half (+01) of the raw pipe 00) is heated and softened by sweat between the electrodes (1) and (5) by appropriately energizing both the electrodes (1) and (5).

In this state, push the rear end of the raw pipe 00 forward with the pushing body (9), and move the movable electrode (5) and the movable receiver (6).
) downwards according to the desired trajectory.

Then, the raw pipe QO) is bent as shown in Fig. 3, but the upper half (+ob) of the raw pipe 00), which stretches in the axial direction with bending, is softened, and the raw pipe α0) The upper end of the inclined rear end surface (10a) of is pressed in the axial direction by the pusher (9), thereby reducing the elongation.
A material component is supplied to one portion, and this portion is prevented from becoming thin or flat.

However, since the lower half of the raw pipe GO), which should be on the inside during bending Q, is processed while remaining hard, there is little risk of buckling, and the bending process can be performed with little change in the cross-sectional shape as a whole. I can do it.

Note that if the wall thickness of the material tube exceeds a certain limit, it may be more difficult to bend the inner portion than the outer portion. To fill such a gap, the lower half of the inner part of the material tube is heated and softened in the same manner as described above.

[Brief explanation of the drawing]

The drawings are for explaining the implementation procedure of the present invention. Fig. 1 is a vertical cross-sectional side view before processing, and Fig.
The vertical cross-sectional view taken along the line A-A in the figure, and FIG. 6 is a vertical cross-sectional side view after processing. (1) Fixed electrode (2) Fixed receiver (3) (4)
Recess (5) Movable electrode (6) Movable receiver
(7) (8) Recess (9) Push body
QO) Woodwind' (+OA) Rear end face procedural amendment (spontaneous) September 27, 1980 Director of the Japan Patent Office Blind Kazuo Wakasugi 1, Case indication 2ゎ57,4 Patent 暉No. 74105 2 Issued @O name Pipe bending method 3 Relationship with the case of the person making the amendment Patent originator (Shiri) Name Tadashi Nakamura Wound 4
, Agent 6 Number of inventions increased by amendment - 11g m-8, iE
Offig
rAs per the attached sheet (contents of amendment) The scope of the claims is amended as follows. (1) A pipe bending method characterized by bending the raw pipe while heating and softening only the -II1 part of the part of the raw pipe to be bent. (2) Only the outer part of the part of the raw pipe to be bent. (3) A method according to claim 11, characterized in that the inner part of the portion of the blank pipe to be bent is heated and softened. The method described in item (1). (4) Place electrodes in contact with the front end and the rear end of one side of the wood pipe, and energize both electrodes, only on one side of the wood pipe. The method according to any one of claims 11) to (3), characterized in that the vk end surface of the raw pipe is formed into an inclined surface that projects upward. , and a tube bending method characterized by bending the raw pipe while heating and softening only one part of the part of the wood pipe to be bent, and pressing the rear end of the raw pipe in the upper axial direction. (6) Plain pipe bending method. The method described in item (5) of the scope of special TF precision, characterized by heating and softening only the outer 11! part of the pipe to be bent. (7) Only the inner part of the part to be bent of the raw pipe is softened by heating. The method according to claim (5), characterized in that the softening is carried out by heating. (8) An electrode (ta) is brought into contact with the front part and the rear end part of one side of the raw tube, respectively, and both electrodes are energized. The method according to any one of claims (5) to (7), characterized in that only one side of the raw pipe is heated and softened by heating.

Claims (1)

[Claims] (11. A pipe bending method characterized by bending the raw pipe while only one side of the part of the raw pipe to be bent is heated and softened. (2) The raw pipe should be bent. Scope of patent 6n (method described in item 11) characterized by heating and softening only the outer part of the pipe. (3) A method characterized by heating and softening only the inner part of the part to be bent The method according to item (1) of the patent claim p4. (4) By bringing the electrodes into full contact with the front end and the rear end of one side of the blank tube, respectively, and energizing both electrodes, The method according to any one of claims (1) to (3), characterized in that only the -fl11 portion of the woodwind is heated and softened. (5) The rear end surface of the raw pipe is It is characterized in that it is formed into a protruding slanted tan surface, and in a state where only one side 6B of the part to be bent of the raw pipe is heated and softened, the raw pipe is bent while being pressed in the axial direction of the upper rear end of the raw pipe. Pipe bending method. (6) The method according to claim (5), characterized in that only the outer side of the part of the raw pipe to be bent is heated and softened. The method according to claim (5), characterized in that only the inner part is heated and softened. (8) Electrodes are brought into contact with the front end and the rear end of one side of the raw tube, respectively. The method according to any one of claims 5 to 5, characterized in that only one side of the raw tube is heated and softened by applying current to both electrodes.