JPH1058043A - Bending method and bending equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a bulging deformation of a work without causing abrasion of the work, a wear of a die itself, etc., in removing and reducing a saddle warp in a bending process of the work. SOLUTION: A counter pad 5 on which a lower end part of a worke to be bent is abutted is provided inside a groove 3 to be formed in a lower die 1. While an upper die and a lower die 1 are moved relatively close to each other, or when the upper die and the lower die 1 reach a prescribed approaching position, the work is press-held by the upper die and the counter pad 5, and a tension is applied to the work in a direction along a bending line of the work.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bending method and a bending apparatus capable of simultaneously reducing and reducing saddle warpage generated during bending of a plate-shaped work.

[0002]

2. Description of the Related Art Generally, when a plate-shaped work is bent using a bending machine such as a press brake, as shown in FIG. 4, an inner surface 51 of the work extends in a bending line direction, Since the outer surface 52 shrinks in the direction of the bending line, a phenomenon in which the obtained product warps in a saddle shape (generally referred to as “saddle warpage”) occurs, and particularly, bending of long members such as sashes and building materials. Is an important quality issue. For this reason,
Conventionally, various bending methods have been proposed in order to provide a product satisfying straightness by suppressing this "saddle warpage".

The most widely used means for reducing the saddle warpage is a method shown in FIG. In this method, the upper die 61 and the lower die 62 are provided with cambers in the direction of the reverse warp of the saddle warp. Normal,
The camber is attached by inserting a shim or the like between the die and the die mounting surface of the bending machine. Also,
As another example, there has been known a wedge mechanism provided on a mold mounting surface to facilitate the adjustment thereof.

Further, as disclosed in Japanese Patent Application Laid-Open No. 6-238340 (see FIG. 6), a lower die 72 is moved by a wedge mechanism 71 during bending.
A saddle warp reducing mold in which a tensile force in a direction along a bending line is applied to the work 73 by a frictional force between the lower mold 72 and the work 73 has also been proposed.

[0005]

However, the method of providing a camber in a reverse warp direction to a mold as shown in FIG. 5 is expected to have a sufficient effect because the amount of warpage provided is limited. In addition to this, it is difficult to keep the deformed upper mold and lower mold parallel, so even if warpage can be reduced, the angular accuracy in the longitudinal direction will vary. A point occurs.

On the other hand, the method shown in FIG. 6 has been proved to have a great effect on the reduction of the saddle warp, but has some disadvantages as follows. Since the lower mold is moved outward in the longitudinal direction of the bending, the mold and the work make a relative frictional movement, so that the work surface is easily damaged and the mold wears faster. . Since a gap is formed in the divided portion of the mold due to the mechanism, when bending is performed in this gap, as shown in FIG. 7, a bulge 74 is generated in a bent portion of the work corresponding to the gap and the surface 74 is formed. Quality is lost.

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned problems and to reduce saddle warpage during a bending process of a work.
An object of the present invention is to provide a bending method and a bending apparatus capable of suppressing bulging deformation of a work without causing abrasion of a mold itself.

[0008]

Means for Solving the Problems and Functions / Effects In order to achieve the above-mentioned object, a bending method according to the present invention performs bending by pressing a plate-like work between an upper die and a lower die. In the bending method, a contact member with which a lower end of a work to be bent contacts is provided inside a groove formed in the lower die, and the upper die and the lower die are relatively close to each other. While moving, or when the upper mold and the lower mold reach a predetermined proximity position, the work is pressed by the upper mold and the contact member, and the upper mold and the lower mold are During the relative approach movement or when the upper mold and the lower mold reach a predetermined proximity position, a tensile force is applied to the work in a direction along a bending line of the work. is there.

In the bending method according to the present invention, when the work is bent by being sandwiched between the upper die and the lower die, the upper die and the lower die are moved relatively close to each other or the upper die is moved. When the lower mold and the lower mold reach a predetermined proximity position, the work is clamped at a predetermined pressure by the upper mold and the contact member,
During the relative movement of the upper mold and the lower mold, or when the upper mold and the lower mold reach a predetermined proximity position, a tensile force is applied to the work in a direction along the bending line of the work.
In this way, the workpiece is pulled in the lateral direction by the frictional force at the contact surface between the workpiece to be bent and the contact member, so that it is possible to reduce the saddle warping phenomenon that occurs in the workpiece after the removal of the pressing force. According to the present invention,
Since the point where relative slippage occurs is only at the bending line at the lower end of the work, scratches due to friction are not conspicuous, and the lower mold does not cause slippage, so that wear of the mold is suppressed. Further, since no gap is formed in the mold itself, the bulging deformation of the work can be suppressed.

Next, a bending apparatus for specifically realizing the bending method is a bending apparatus for performing bending by pressing a plate-shaped work by an upper die and a lower die.
(A) a contact member provided with a lower end portion of a work to be bent abutted in a groove formed in the lower mold and movably provided in a vertical direction and a bending line direction of the work; When the upper mold and the lower mold are relatively moved close to each other, or when the upper mold and the lower mold reach a predetermined proximity position, the work is moved by the upper mold and the contact member. And (c) while the upper mold and the lower mold are relatively moved close to each other or between the upper mold and the lower mold. And a drive mechanism for driving the contact member in a direction in which a tensile force is applied to the work along a bending line of the work when the work reaches a predetermined proximity position.

In the present invention, when the workpiece is bent by being sandwiched between the upper mold and the lower mold, the upper mold and the lower mold are relatively moved close to each other, or the upper mold and the lower mold are moved. When the workpiece reaches a predetermined proximity position, the workpiece is clamped between the upper mold and the upper mold by the pressure applied to the contact member by the clamping mechanism. During the movement or when the upper mold and the lower mold reach a predetermined proximity position, the work is pulled in a direction along the bending line of the work by a drive mechanism that drives the contact member. Thus, as in the above-described bending method, the saddle warpage phenomenon that occurs in the work after the pressing force is removed is reduced, and the work surface is not noticeably abraded due to friction, the lower mold wear is suppressed, and the work bulges. Is also suppressed.

In this bending apparatus, the pinching mechanism may be an elastic body that constantly urges the contact member upward, or a fluid pressure mechanism that drives the contact member upward. It may be a cylinder. Further, the drive mechanism may be a wedge mechanism attached to the contact member, or may be a fluid pressure cylinder attached to the contact member.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of a bending method and a bending apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a view showing a lower die structure in a bending apparatus according to one embodiment of the present invention, wherein (a) is a longitudinal sectional view, and (b) is an AA sectional view of (a). It is.

In the present embodiment, the lower mold 1 has a holding table 2 mounted on a lower mounting table (not shown) of the press brake, and a central portion fixed on the holding table 2 along the longitudinal direction. A die 4 having a groove 3 and a counter pad (contact member) 5 provided in the groove 3 of the die 4 and having a two-part structure in the longitudinal direction are provided.

The counter pad 5 has a wedge-shaped first cam slider 6 fixed to the lower surface of the counter pad 5 and a wedge-shaped second cam slider 6 fixed to the upper surface of the holding table 2.
The cam slider 7 can be moved in the vertical direction and the lateral direction (direction along the bending line of the work) by engaging the respective inclined surfaces with each other. Here, when the pair of counter pads 5 and 5 are moved downward, they are moved in a direction away from each other with respect to a center line in the longitudinal direction of the bending.

A compression spring 8 is provided on the first cam slider 6, and a spring receiver 9 attached to an end of the compression spring 8 is attached to an end surface of the second cam slider 7 or a bracket 10 fixed to the holding table 2. By being slidably held, these first cam sliders 6 are constantly urged to push up the counter pad 5.

With this configuration, as shown in FIG. 2, the work W to be bent is placed on the die 4 of the lower die 1 and the upper die (punch) 11 is lowered. The work W is sandwiched and bent by the upper mold 11 and the groove 3 formed in the die 4.

With the progress of the bending, the lower end of the work W (the position corresponding to the bending line) is pressed by the punch 11 and the counter pad 5 by the spring force of the compression spring 8, and at the same time, the first cam slider 6 The engagement with the second cam slider 7 causes the counter pad 5 to move obliquely downward against the urging force of the compression spring 8. Along with the movement of the counter pad 5, a tension is applied to the work W so that the work W is pulled outward with respect to the center line CC in the bending length direction. Therefore, a process that can significantly reduce the saddle warpage phenomenon after processing that has conventionally occurred while bending the work W can be performed.

After the bending is performed, the punch 1
When 1 is raised, the pressing force from above on the counter pad 5 is released, and the counter pad 5 returns to the original position (the position shown in FIG. 1) by the urging force of the compression spring 8.

According to the bending apparatus of the present embodiment, the point at which slippage occurs relatively at the time of bending is the lower end of the work (the point corresponding to the bending line), and the lower die does not slip. Abrasion due to friction is not conspicuous on the surface of the work W, and wear of the mold can be suppressed. Further, since there is no gap in the lower mold itself as in the conventional example shown in FIG. 6, swelling deformation of the work as shown in FIG. 7 can be suppressed.

In this embodiment, the first cam slider is urged by the compression spring. However, a modification in which another elastic member such as urethane is used instead of the compression spring is also possible. Further, a hydraulic cylinder such as a hydraulic cylinder or a pneumatic cylinder may be used. As described above, the use of the fluid pressure cylinder has an advantage that the work can be clamped with a constant clamping pressure regardless of the vertical position of the counter pad.

FIG. 3 shows a lower die structure in a bending apparatus according to another embodiment of the present invention.

In this embodiment, the counter pad 5 is supported by the support 22 via a plurality of sliding members 21, and the support 22 is mounted on the support 2 by a plurality of compression springs. The counter pad 5 is supported so as to be movable in the vertical direction, and the counter pad 5 is moved laterally by a hydraulic cylinder 24 such as a hydraulic cylinder or a pneumatic cylinder fixed to the apparatus main body. Here, in order that the driving force of the hydraulic cylinder 24 can be transmitted to the counter pad 5 even if the counter pad 5 moves up and down, there is a space between the hydraulic cylinder 24 and the counter pad 5 as shown in FIG. A connecting member 25 having a slit as shown in FIG.

According to the lower die structure of this embodiment, the mechanism for moving the counter pad 5 in the vertical direction and the mechanism for moving the counter pad 5 in the horizontal direction are independent of each other. Can be provided.

In this embodiment, a modification in which the vertical movement and the horizontal movement of the counter pad are performed by separate hydraulic cylinders is also possible.

[Brief description of the drawings]

FIG. 1 is a view showing a lower die structure in a bending apparatus according to one embodiment of the present invention, where (a) is a longitudinal sectional view and (b) is an AA section of (a). FIG.

FIGS. 2A and 2B are views showing the bending apparatus of the present embodiment in a state where a workpiece is bent.

3A and 3B are diagrams showing a lower die structure in a bending apparatus according to another embodiment of the present invention, wherein FIG. 3A is a longitudinal sectional view and FIG. 3B is a perspective view of a connecting member. .

FIG. 4 is an explanatory diagram showing the principle of occurrence of saddle warpage.

FIG. 5 is an explanatory diagram showing an example of a conventional saddle warp reduction method.

FIG. 6 is an explanatory view showing another example of a conventional saddle warp reduction method.

FIG. 7 is a diagram for explaining a drawback of the conventional example shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower die 2 Holding stand 3 Groove 4 Die 5 Counter pad (contact member) 6 First cam slider 7 Second cam slider 8, 23 Compression spring 25 Fluid pressure cylinder

Claims (6)

[Claims] 1. A bending method in which a plate-shaped work is pressed by an upper die and a lower die to perform bending, wherein a lower end of the work to be bent is formed in a groove formed in the lower die. Providing a contact member where the part is in contact, while the upper mold and the lower mold are relatively close to each other or when the upper mold and the lower mold reach a predetermined proximity position, The work is squeezed by the upper mold and the contact member, and during the relative approach movement of the upper mold and the lower mold or when the upper mold and the lower mold reach a predetermined proximity position, A bending method, wherein a tensile force is applied to the work in a direction along a bending line of the work. 2. A bending apparatus for performing bending by pressing a plate-shaped work between an upper die and a lower die, wherein (a) bending is performed inside a groove formed in the lower die. (B) a contact member which is provided so that the lower end of the work is brought into contact with the work and which is movable in the vertical direction and the bending line direction of the work.
When the upper mold and the lower mold are relatively moved closer to each other or when the upper mold and the lower mold reach a predetermined proximity position, the upper mold and the contact member move the workpiece by the upper mold and the contact member. A pressing mechanism for applying a predetermined pressure to the contact member so as to press, and (c) while the upper die and the lower die are relatively close to each other or when the upper die and the lower die are A bending apparatus comprising: a drive mechanism that drives the contact member in a direction in which a tensile force is applied to the work along a bending line of the work when the work reaches a predetermined proximity position. 3. The bending apparatus according to claim 2, wherein the clamping mechanism is an elastic body that constantly biases the contact member upward. 4. The bending apparatus according to claim 2, wherein the clamping mechanism is a fluid pressure cylinder that drives the contact member upward. 5. The bending apparatus according to claim 2, wherein the drive mechanism is a wedge mechanism attached to the contact member. 6. The bending apparatus according to claim 2, wherein the drive mechanism is a hydraulic cylinder attached to the contact member.