JP2000135517A - Push-through type bending equipment and bending method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means to effectively prevent or control wrinkling of the work in push-through type bending of the work made of a metallic hollow material. SOLUTION: This device for performing bending by forcefully pushing a work W1 through work passage holes 11 and 12 of a fixed die 1 and a gyro die 2 by means of a work feeder, is equipped with the fixed die 1, the gyro die 2, and the work feeder. In this case, an inner periphery of the work passage hole 11 of the fixed die 1 is composed of multiple movable liners 3A and each movable liner 3A is held in such a way that it can move in approaching and leaving direction to and from the center portion of the work passage hole 11, and a pushing means 4 to press each movable linear 3A against the surface of the work W1 inserted through the work passage hole 11 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus and a processing method for bending a hollow material such as an aluminum hollow material or a steel pipe in a push-through manner.

[0002]

2. Description of the Related Art In recent years, a push-through type bending apparatus called a multi-bender has been widely used for bending hollow materials such as aluminum hollow members and steel pipe materials. As shown in FIG. 5, the bending apparatus includes a fixed mold (50) having a work conduction hole (51) and a work conduction hole (61) provided behind the fixed mold (50). A gyro mold (60) and a work feeder (70) disposed in front of the gyro mold (60), and the two dies (50) (6) for the work (W) by the work feeder (70).
0) and the cooperative action of the turning, displacement, and rotation of the gyro mold (60), the fixed dies (50) serving as a fulcrum and the gyro mold (60) serving as a working point. (W), torsion, torsion bending, and the like.

[0003] However, in general, when a hollow material is bent, there is a problem that wrinkles are easily generated on the surface of the bent product, especially on the inside of the bend where a compressive stress is applied. This is a common problem in bending.

[0004] In order to prevent such wrinkles, a method of applying a shear strain with a booster has been adopted in the bending process of the rotary pulling bending method, in addition to using a mandrel (core bar). However, in push-through bending, it is extremely difficult to adopt a wrinkle-preventing mechanism like a rotary pull-bending type, and the use of a mandrel is the only means. It has not been prevented.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a processing apparatus and a processing method capable of effectively preventing or suppressing wrinkles in a push-through bending process on a workpiece made of a hollow material. It is intended to provide.

[0006]

In order to achieve the above object, a press-through bending apparatus according to a first aspect of the present invention comprises: a fixing die having a work conducting hole; A gyro mold provided to be turned, displaced, and rotatable behind the mold, and a work feeder arranged in front of the fixed mold, and a work made of a linear metal hollow material is provided by a work feeder. In the one in which the bending is performed by forcibly pushing through the fixed mold and the gyro mold, the inner peripheral portion of the work conduction hole of the fixed mold is constituted by a plurality of movable liners long in a hole direction, and each movable liner is provided. Is held in the mold body such that it can be displaced in the perspective direction with respect to the center of the work conduction hole, and press means for pressing each movable liner against the surface of the work inserted into the work conduction hole is provided. It is characterized in that.

[0007] In the push-through bending apparatus having the above structure,
When bending a work made of hollow material, wrinkling of the work is effectively prevented by performing the work while pressing the movable liner with the pressing means on the peripheral surface of the work inserted into the work conduction hole of the fixed mold Or can be suppressed. The principle is not clear, but is presumed as follows.

First, in the conventional press-through bending apparatus, the work conduction hole of the fixed mold corresponds to the cross-sectional outer shape of the work, but is set slightly larger than the work in order to smoothly insert the work. Since the work in the work conduction hole has a margin of movement due to the dimensional difference, the fulcrum of the bending process shifts to the inlet side from the outlet portion of the original fixed mold, thereby causing wrinkles inside the fixed mold. It is considered to be in a state of occurrence. On the other hand, in the push-through bending apparatus according to the present invention, the work can be restrained appropriately by pressing the movable liner in the fixed mold, so that the fulcrum of the bending processing is fixed at the outlet side of the original fixed mold. It is thought that the frictional force is generated by the sliding contact while being kept at the position, and a shear stress is applied to the work, which leads to prevention or suppression of wrinkles.

According to a second aspect of the present invention, in the push-through bending apparatus according to the first aspect, the pressing means is for screwing into the mold body from outside so that the front end faces the rear side of the movable liner. Since it is composed of bolts, the device configuration of the fixed mold portion is simple, and failures and the like hardly occur.

According to the third aspect of the present invention, the first or second aspect is provided.
In the push-through bending apparatus, the workpiece to be machined has a rectangular cross-sectional outer shape, and the fixed mold has four movable liners corresponding to each side face of the workpiece. In this case, by pressing the movable liner from all sides on a work having a rectangular cross-sectional shape in the fixed mold, an appropriate restrained state can be reliably exhibited.

According to a fourth aspect of the present invention, there is provided the push-through bending apparatus according to any one of the first to third aspects, wherein all the surfaces of the work inserted into the work conduction holes of the fixed mold are pressed by pressing means. The gist of the present invention is a push-through bending method in which bending is performed while pressing the movable liner.

[0012]

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

The push-through bending apparatus according to the first embodiment shown in FIGS. 1A and 1B includes a fixed mold 1 having a work conduction hole 11 and a rear side of the fixed mold 1. Turned to,
A gyro mold (2) having a work conduction hole (21) provided so as to be displaceable and rotatable, and a rectangular cylindrical work (W1) provided in front of a fixed mold (1) and a fixed mold (1). FIG. 4 in that a work feeder (not shown; see reference numeral 70 in FIG. 4) made of a press or the like forcibly conducting the work through holes (11) and (21) of the gyro mold (2) is provided. This is the same as the conventional bending apparatus described above.

However, the stationary mold (1) is provided with four movable liners (3A)... Constituting the periphery of the work conduction hole (11) inside a box frame-shaped mold body (10). I have. Each movable liner (3A) has a rectangular rod shape extending in the hole direction of the work conduction hole (11) and has a length that extends over the entire length of the mold body (10). 31), and in each of the upper, lower, left and right concave grooves (12) facing the work conduction hole (11), the work conduction hole (1) is formed.
It is fitted so that it can be displaced in the near and far directions with respect to the center of 1).

Further, pressing bolts (4) are screwed into the mold body (10) from the outside at three positions corresponding to the front and rear portions and the intermediate portion of each movable liner (3A). The tips of (4) ... protrude into the respective grooves (12) and face the back surface (3a) of the movable liner (3A). Therefore, by tightening these bolts (4), the movable liner (3A) is pushed out toward the center of the work conduction hole (11). A base (13) is fixed to the exit side of the mold body (10) via mounting bolts (5). The work conduction hole (1) in the base (13).
1a) is a square corresponding to the cross-sectional outer shape of the work (W1).

In order to bend the work (W1) by the push-through bending apparatus having the above structure, first, the pressing bolts (4)... Of the fixed mold (1) are loosened.
The work (W1) is fixed to the fixed mold (1) and the gyro mold () so that a gap can be formed between the pressing portion (31) of each movable liner (3A) and the outer surface of the work (W1) to be inserted. By passing through the work conduction holes (11) and (21) of 2) and then tightening the pressing bolts (4).
The four movable liners (3A) are pressed against the work (W1) from all sides. Then, while the work (3A) is forcibly fed by the work feeder in the pressed contact state, the gyro mold (2) is displaced and turned so as to have a required bending radius, so that the fixed mold ( The workpiece (W1) is bent by using 1) as a fulcrum and the gyro mold (2) as an action point.

The pressing force of the movable liner (3A) to the work (W1) is such that the work (W1) hinders the pushing of the work (W1) in accordance with the processing conditions such as the bending radius and the pushing speed and the occurrence of wrinkles. It may be appropriately adjusted according to the degree of tightening of the pressing bolts (4) so as to be in an appropriate restrained state within the range not present.

[0018] The bent product obtained in this manner has no wrinkles on the inside of the bend, is very slight even if it is present, and has high quality and high commercial value. Also, in the bending process, except for adjusting the pressing bolts (4) of the fixed mold (1), it is only necessary to simply push the work (3A) through, so that much labor is required as in the case of using a mandrel. It is easy to operate without requiring.

In the push-through bending apparatus according to the present invention,
The present invention can be applied not only to the rectangular cylindrical work (W1) as in the first embodiment but also to other hollow materials having various cross-sectional shapes. What is necessary is just to use the thing whose contact part shape corresponds to the cross-sectional outer shape of a workpiece.

For example, in the second embodiment shown in FIG. 2, since a workpiece (W2) having a fin (F) continuous in the longitudinal direction on the outer peripheral portion of a rectangular cylindrical main body is to be machined, a fixed mold (1) is used. ), A movable liner (3B) provided with a fin fitting groove (32a) in a flat pressing contact portion (32) on the side facing the side surface having the fin (F) of the work (W2). In the other three directions, the same movable liner (3
A) is arranged. Further, in the third embodiment shown in FIG. 3, corresponding to a cylindrical workpiece (W3), four fixed concave molds (1) each having a concave contact portion (33) in a fixed mold (1). The movable liners (4C) are arranged vertically and horizontally. Further, the present invention is not limited to a work having a cross-sectional shape that is axisymmetric, and may be applied to a work having an irregular cross-section that is not axisymmetric.

Further, the number of movable liners of the fixed mold (1) is not limited to four as in the first to third embodiments, but may be two, three, or five or more according to the sectional outer shape of the work. It is also possible to configure the number of the workpieces in such a manner that the work can be in an appropriate restrained state in combination with the shape of the liner itself. For example, in the case of a work having a rectangular cross section, such as the rectangular tubular work (W1) used in the first embodiment, it is certain that the work is sandwiched from four sides by four movable liners as in the same embodiment. As in the fourth embodiment shown in FIG. 4 (a), V-shaped cross-section pressing contact portions (3) arranged on both sides in the diagonal direction of the work.
By sandwiching between the pair of movable liners (3D) and (3D) having 4), the structure of the mold itself becomes simpler.
In the cylindrical work (W3) used in the third embodiment,
As in the fifth embodiment shown in FIG. 4B, a pair of movable liners (3E) and (3E) having a concave arc-shaped pressing portion (35) on both sides.
E), and a structure in which three components are used to sandwich the device from three directions is also possible.

On the other hand, as the pressing means for pressing the movable liner against the peripheral surface of the work, other means such as a hydraulic cylinder and an air cylinder can be adopted in addition to the pressing bolt (4) shown above. However, pressing bolt (4)
In the case of (1), there is an advantage that the device configuration of the fixed mold portion is simplified, and a failure or the like hardly occurs.

[0023]

According to the first aspect of the present invention, a plurality of fixed dies serving as fulcrum portions of a plurality of fixed dies are arranged inside as a processing device for press-through bending a work made of a metal hollow material. Since the work can be appropriately restrained by the movable liner, wrinkles of the work due to bending can be effectively prevented or suppressed, and a high-quality bent product can be efficiently manufactured at low cost.

According to the second aspect of the present invention, in the push-through bending apparatus, since the pressing bolt is used as the movable liner pressing means, the apparatus configuration of the fixed mold portion is simplified, and a failure or the like occurs. There is an advantage that it is difficult.

According to the third aspect of the present invention, there is provided a push-through type bending apparatus capable of effectively preventing or suppressing wrinkles of a workpiece caused by bending, with respect to a workpiece having a rectangular cross-sectional profile. Is done.

According to the fourth aspect of the present invention, there is provided a preferred bending method using the above-described push-through bending apparatus.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional side view of a main part of a push-through type bending apparatus according to a first embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along a roll line in FIG.

FIG. 2 is a vertical sectional front view of a fixed mold in the bending apparatus according to the second embodiment.

FIG. 3 is a vertical sectional front view of a fixed mold in the bending apparatus according to the third embodiment.

FIG. 4A is a longitudinal sectional front view showing an arrangement relationship between a movable liner of a fixed mold and a workpiece in the bending apparatus of the fourth embodiment, and FIG. 4B is a bending apparatus of the fifth embodiment; FIG. 4 is a longitudinal sectional front view showing an arrangement relationship between a movable liner of a fixed mold and a workpiece in FIG.

FIG. 5 is a partial cross-sectional side view of a conventional push-through bending apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Fixed mold 10 ... Die main body 11 ... Work conduction hole 12 ... Depressed groove 2 ... Gyro mold 21 ... ··· Work conduction holes 3A to 3E ··· Movable liner 3a ··· Back surface 31 to 35 ····································· Pressing bolt (pressing means)

Claims (4)

[Claims] 1. A fixed mold having a work conducting hole, a gyro mold having a work conducting hole and arranged to be turned, displaced, and rotatable behind the fixed mold, and a front of the fixed mold. And a work feeder arranged in a press-through bending apparatus that performs a bending process by forcibly pushing a work made of a linear metal hollow material through the fixed mold and the gyro mold by a work feeder. The inner peripheral portion of the work conduction hole of the fixed mold is composed of a plurality of movable liners that are long in the hole direction, and each movable liner is held in the mold body so as to be displaceable in a direction closer to the center of the work conduction hole. A push-through type bending apparatus further comprising pressing means for pressing each movable liner against the surface of the work inserted into the work conduction hole. 2. The push-through bending apparatus according to claim 1, wherein said pressing means comprises a pressing bolt which is screwed into the mold body from the outside and has a front end facing the rear side of the movable liner. 3. The push-through bending apparatus according to claim 1, wherein the cross-sectional outer shape of the work to be processed is rectangular, and the fixed mold includes four movable liners corresponding to each side surface of the work. 4. A press-through means for pressing all movable liners against a peripheral surface of a work inserted into a work conduction hole of a fixed mold using the push-through bending apparatus according to any one of claims 1 to 3. A press-through bending method, wherein the bending is performed while being performed.