JPH09192743A - Metal plate bending method and bending machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a metal plate from displacing and to accurately bend it at the time of re-bending after measuring the bending angle. SOLUTION: In a time of separating a punch P and a die D, and generating a spring back, because the pressing force is energized to the mutual approaching direction, the metal plate W is made always in a state of being clamped with the punch P and the die D. Therefore, because the positional relation of the punch P and the die D against the metal plate W is kept definitely in the case of re-bending after correcting the D-value from the result of the angle measurement, the displacement of the bending position can be prevented. For example, in the case of the die D being energized to the punch P side with an elastic member 17, even in the case of separating the punch P and the die D, the metal plate W is clamped with the punch P and the die D. Further, the punch P is made enough being hung with the elastic member. Further, the punch P is made enough freely attachable and detachable or freely moving up and down by a prescribed amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for bending a plate material and a bending machine, and more particularly to a method for bending a plate material and a bending machine when bending is performed again after measuring a bending angle. .

[0002]

2. Description of the Related Art Conventionally, when bending a plate material in cooperation with the relative movement of a punch and a die, the punch and the die are moved relative to each other so that a predetermined bending angle (for example, 90 °) is achieved. Bending is generally performed by determining the distance (D value).

Such D value is determined by using various parameters such as plate thickness and tensile strength, and D = D0 + deflection of press brake side plate + deflection of upper and lower tables + upper limit valve opening. Here, D0 means a geometrical D value when the deflection is not considered.

Referring to FIG. 5, it is difficult to calculate the P2 point at a predetermined angle due to the tolerance of the plate thickness and the tensile strength, and after the bending process is performed using the D value (P1 in FIG. 5).
Point), when the punch P and the die D are separated from each other and the plate material W is taken out from the die D, the plate material W returns by the elasticity of the plate material itself (spring back), so the true bending angle after this spring back is obtained (P2 in FIG. 5). Point) necessary.

In order to confirm the bending angle, the plate material W is applied to the square 1 as shown in FIG. 6, or the angle is confirmed, or the punch P and the die D are relatively moved as shown in FIG. The bending force after springback is measured by using the indicator 3 without separating the plate material W from the die D by weakening the pressing force by separating.

From the result of measuring the true bending angle after the spring back as described above, when the predetermined bending angle is not reached, the D value is corrected and the bending process is continued to the predetermined angle. To get

[0007]

However, in such a conventional technique, in the case shown in FIG. 6, the plate material W is once taken out from the die D and returned to the die D again after the angle measurement. As shown in FIG. 8, when the bending process is performed again, the relative positional relationship between the punch P and the plate material W is deviated, and the final bent shape is deformed as shown in FIG. There is a possibility that it will become a thing.

Further, in the case shown in FIG. 7, the plate material W is not taken out from the die D after bending, but the plate material W is merely placed on the die D. Therefore, the plate material W is again punched by the punch P. When pushing in, the contact point shifts,
In the case described above, the bending process may be similarly deformed.

The object of the present invention has been made by paying attention to the conventional technique as described above, and when the bending process is carried out again after the bending angle is measured, the deviation of the plate material is prevented and the accurate bending process is carried out. It is an object of the present invention to provide a bending method and a bending machine for a plate material that can be performed.

[0010]

In order to achieve the above object, a method of bending a plate material according to a first aspect of the present invention is a plate material that bends a plate material in cooperation with the approach and separation of a punch and a die. In the bending method, the punch and the die are moved relatively close to each other, and the punch and the die are moved relative to each other to feed a D value corresponding to a desired bending angle to perform bending, and then the punch and the die are moved relative to each other in order to generate a springback in the plate material. When the punches and dies are separated from each other, the punches and the dies are separated from each other within a range in which the punches and the dies are not separated from the plate material, and the punches and dies are always in contact with the plate material.

Therefore, when the punch and the die are relatively separated from each other in order to measure the true bending angle after the spring back, the punch and the die are always in contact with both sides of the plate material to clamp the plate material. From the measurement result of the angle, the positional relationship between the punch and the die with respect to the plate material at the time of further bending is always kept constant. As a result, it is possible to prevent the bending point position from being displaced when the bending process is performed again, so that it is possible to perform the highly accurate bending process.

According to a second aspect of the present invention, there is provided a method of bending a plate material, wherein the die according to the first aspect is biased by an elastic member in the approaching direction of the punch and the die.

Therefore, even when the punch and the die are relatively separated from each other to cause spring back of the plate material, the die is urged toward the punch side by the elastic member, so that the die presses the plate material against the punch. Become. Therefore, the plate material is clamped by the die and the punch.

According to a third aspect of the present invention, there is provided a method for bending a plate material, characterized in that the punch according to the first aspect is suspended by an elastic member at a lower end portion of an upper table on which the punch is mounted. is there.

Therefore, when the punch and the die are relatively separated to cause the spring back of the plate material, the punch lowers by its own weight against the restoring force of the elastic member, so that the punch presses the plate material against the die. Become. Therefore, the plate material is clamped by the die and the punch.

According to a fourth aspect of the present invention, there is provided a method for bending a plate material, wherein the punch according to the first aspect is attached to a lower end portion of an upper table on which the punch is attached so as to be detachable and movable by a predetermined amount. It is what

Therefore, when the punch is raised and the punch and the die are relatively separated from each other, the punch lowers by its own weight, so that the punch presses the plate material against the die. Therefore, the plate material is clamped by the die and the punch.

A plate material bending machine according to a fifth aspect of the present invention is a plate material bending machine which cooperates with a punch and a die by approaching / separating the plate material to bend the plate material, wherein the punch and / or the die are: It is characterized in that it is provided so as to be movable in the approaching direction with a predetermined pressing force in the approaching direction.

Therefore, when the punch and the die are separated from each other to cause the spring back, the punch and / or the die are biased by the pressing force in the direction of approaching each other, so that the plate material is always clamped to the punch and the die. It is in a state of Therefore, when the bending process is performed again based on the bending angle measurement result, the positional relationship between the punch and the die with respect to the plate material is kept constant, so that the bending position can be prevented from being displaced. Thereby, highly accurate bending can be performed.

According to a sixth aspect of the present invention, there is provided a plate material bending machine comprising an elastic member for urging the die according to the fifth aspect in the approaching direction of the punch and the die.

Therefore, since the die is biased toward the punch by the elastic member, the plate material is pressed against the punch by the die and clamped even when the punch and the die are separated from each other.

According to a seventh aspect of the present invention, there is provided a plate material bending machine comprising the elastic member for suspending the punch according to the fifth aspect at a lower end portion of an upper table on which the punch is mounted. is there.

Therefore, since the punch is suspended by the elastic member, when the punch and the die are separated from each other, the elastic member extends due to the weight of the punch and the plate material is always clamped by the punch and the die.

According to an eighth aspect of the present invention, there is provided a plate material bending machine, comprising a fixture for mounting the punch according to the fifth aspect on a lower end portion of an upper table so as to be detachable and movable by a predetermined amount. To do.

Therefore, if the fixture is kept unclamped when the punch and the die are separated from each other, the plate material is pressed against the die by the weight of the punch, so that the plate material is always clamped.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 4 shows the entire press brake 5 which is a plate bending machine. In this press brake 5, side plates 7 are provided upright on both left and right sides, and a lower table 9 is fixed to the lower front surface between the side plates 7. A pair of cylinders 11 is provided on the upper front surface between the side plates 7.

A die D is detachably attached to the die holder 13 provided at the upper end of the lower table 9. Further, the cylinder 11 has a ram 1 that can be raised and lowered.
5, a punch P is detachably attached to the lower end of the ram 15 so as to face the die D.

Therefore, the plate material W is provided between the die D and the punch P.
Is inserted and positioned, the cylinder 11 is driven by a foot pedal or the like (not shown) to move the ram 15 up and down, and the plate material W is bent by the cooperation of the die D and the punch P.

Referring to FIG. 1, the die D is urged upward by a spring 17 inside a die holder 13 provided at the upper end of the lower table 9 within a range where it does not fall off.

According to this structure, in order to measure the bending angle after the first bending process is completed, the punch P is lifted up partway to cause the spring back of the plate material W, but the die D serves as an elastic member. Since the plate material W is pushed up by the spring 17 to press the plate material W against the punch P, the plate material W is always clamped between the punch P and the die D. In this state, the true bending angle after springback is measured.

As a result, if further bending work is required from the measurement results, it is possible to prevent the positional deviation between the punch P and the plate material W when the D value is corrected and the punch P is lowered again to perform bending work. Therefore, it is possible to perform bending processing at an accurate bending angle.

Here, it is desirable that the amount by which the punch P is raised is approximately geometric D value + 0.1 to 0.5.

FIG. 2 shows another embodiment.
That is, at the lower end of the ram 15, there is provided a hydraulic chamber 19 as a fixture for detachably mounting the punch P.

Therefore, pressure oil is supplied to the hydraulic chamber 19 to clamp the punch P during bending, and pressure oil is extracted from the hydraulic chamber 19 and unclamped to remove the punch P when the punch P is replaced.

According to this structure, when the ram 15 is partially raised to reduce the pressure applied to the plate W and to cause the spring back after the first bending process is completed, the pressure of the hydraulic chamber 19 is increased. When the oil is drained, the punch P is unclamped, so that the weight of the punch P is loaded on the plate material W despite the rise of the ram 15.

Therefore, the plate material W is always punched by the punch P and the die D.
It is clamped between and, and the true bending angle after springback is measured in this state.
And, if it is necessary to bend again from the measurement results,
Even if the punch P is lowered, it is possible to prevent the positional deviation between the punch P and the plate material W, so that it is possible to perform bending at an accurate bending angle.

Here, the amount by which the punch P is raised is preferably about the geometrical D value +0.1 to 0.5 as in the case described above.

FIG. 3 shows still another embodiment. That is, the punch P is provided at the lower end of the ram 15.
Is suspended by a spring 21 as an elastic member. Therefore, during bending, the punch P abuts against the ram 15 and the pressing force is transmitted, but when the ram 15 is raised, the punch P hangs down by its own weight.

According to this structure, when the ram 15 is lifted halfway to cause springback after the first bending process is completed, the punch P hangs down by its own weight. The weight of the punch P is loaded on the plate material W.

Therefore, the plate material W is always in the punch P and the die D.
It is clamped between and, and the true bending angle after springback is measured in this state.
And, if it is necessary to bend again from the measurement results,
Even if the punch P is lowered, it is possible to prevent the positional deviation between the punch P and the plate material W, so that it is possible to perform bending at an accurate bending angle.

Here, the amount by which the punch P is raised is set to a geometrical D value of about +0.1 to 0.5, as in the case described above.

The present invention is not limited to the above-described embodiment, but can be embodied in other forms by making appropriate changes. That is, in the above-described embodiment, the case where the force is applied to only one of the punch P and the die D has been described, but these may be combined and applied to both the punch P and the die D. .

[0044]

As described above, in the method of bending a plate material according to the first aspect of the present invention, when the punch and the die are relatively separated to measure the true bending angle after springback, the punch and the die are separated. Since the die is always in contact with both sides of the plate material to clamp the plate material, the positional relationship between the punch and the die with respect to the plate material when performing further bending work is always ensured from the measurement result of the bending angle. This gives D
Since it is possible to prevent the position of the bending point from being displaced when the value is corrected and the bending process is performed again, it is possible to perform the bending process with high accuracy.

In the plate material bending method according to the second aspect of the present invention, since the die is biased toward the punch side by the elastic member even when the punch and the die are relatively separated from each other in order to cause the spring back of the sheet material. , The die presses the plate material against the punch. Therefore, the plate material is always clamped by the die and the punch, and it is possible to prevent the positions of the punch and the die from being displaced with respect to the plate material when the bending process is performed again.

In the method of bending a plate material according to the third aspect of the present invention, when the punch and the die are relatively separated to cause springback of the plate material, the punch lowers by its own weight against the restoring force of the elastic member. The punch presses the plate material against the die. Therefore, the plate material is always clamped by the die and the punch, and it is possible to prevent the positions of the punch and the die from being displaced with respect to the plate material when the bending process is performed again.

In the plate material bending method according to the fourth aspect of the present invention, when the punch is unclamped and the punch and the die are relatively separated from each other, the punch lowers by its own weight. Therefore, the punch presses the plate material on the die. Become. Therefore, the plate material is always clamped by the die and the punch, and it is possible to prevent the positions of the punch and the die from being displaced with respect to the plate material when the bending process is performed again.

In the plate bending machine according to the fifth aspect of the present invention, when the punch and the die are separated from each other to cause the spring back, the pressing force is applied in the direction in which the punch and the die approach each other. Therefore, the plate material is always clamped by the punch and the die. For this reason,
When the D value is corrected from the bending angle measurement result and the bending is performed again, the positional relationship between the punch and the die with respect to the plate material is kept constant, so that the bending position can be prevented from being displaced. Thereby, highly accurate bending can be performed.

In the plate material bending machine according to the sixth aspect of the present invention, since the die is biased toward the punch side by the elastic member, the plate material is always clamped by the punch and die even when the punch and die are separated. become. Thereby, the bending position can be kept constant even when bending is performed again, and highly accurate bending can be performed.

In the plate material bending machine according to the invention of claim 7, since the punch is suspended by the elastic member, when the punch and the die are separated from each other, the elastic member extends and the plate material is always clamped by the punch and the die. Will be done. Thereby, the bending position can be kept constant even when bending is performed again, and highly accurate bending can be performed.

In the plate bending machine according to the invention of claim 8, when the fixture is unclamped when the punch and the die are separated from each other, the punch presses the plate against the die by its own weight. It will be clamped. Thereby, the bending position can be kept constant even when bending is performed again, and highly accurate bending can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an essential part of a plate material bending machine according to the present invention.

FIG. 2 is a sectional view showing another embodiment.

FIG. 3 is a cross-sectional view showing still another embodiment.

FIG. 4 is a side view showing a press brake to which the plate material bending method and the bending machine according to the present invention are applied.

FIG. 5 is a graph showing a relationship between a D value and a bending angle.

FIG. 6 is an explanatory diagram showing angle measurement by a squarer.

FIG. 7 is an explanatory diagram showing angle measurement by an indicator.

FIG. 8 is an explanatory view showing a state in which a bending position is displaced by a conventional bending method.

FIG. 9 is an explanatory diagram showing an improperly bent state.

[Explanation of symbols]

 5 Plate material bending machine 15 Ram (upper table) 17, 21 Spring (elastic member) 19 Hydraulic chamber (mounting tool) P Punch D Die W Plate material

Claims (8)

[Claims] 1. A bending method for a plate material, which bends a plate material in cooperation with the approach and separation of a punch and a die, wherein the punch and the die are relatively brought close to each other to obtain a D value for a desired bending angle. After performing the bending process by only feeding it, when the punch and the die are relatively separated from each other in order to cause the spring to the plate material, the punch and the die are separated from each other within the range in which the punch and the die do not separate from the plate material, and A bending method characterized in that the die is kept in contact with the plate material. 2. The method for bending a plate material according to claim 1, wherein the die is biased by an elastic member in the approaching direction of the punch and the die. 3. The method for bending a plate material according to claim 1, wherein the punch is suspended by an elastic member at a lower end portion of an upper table on which the punch is mounted. 4. The method of bending a plate material according to claim 1, wherein the punch is detachably attached to a lower end portion of an upper table on which the punch is attached and is movable by a predetermined amount. 5. A plate material bending machine for bending a plate material in cooperation with the approach and separation of the punch and the die, wherein the punch and / or the die have a predetermined pressing force in the approaching direction. A plate material bending machine characterized by being provided so as to be movable in the approaching direction. 6. The plate material bending machine according to claim 5, further comprising an elastic member for urging the die in an approaching direction of the punch and the die. 7. The plate material bending machine according to claim 5, further comprising an elastic member for suspending the punch at a lower end portion of an upper table on which the punch is mounted. 8. The plate bending machine according to claim 5, further comprising a mounting tool for mounting the punch on the lower end of the upper table so as to be detachable and movable by a predetermined amount.