CN117813169A - Bending machine and bending method - Google Patents

Abstract

A bending machine (1) is provided with: hydraulic cylinders (9L, 9R) for freely adjusting the inclination state of the upper table (7); eccentric shaft units (19L, 19R) that bend a part of the lower table (5); and a control device (30). The control device (30) sets the inclined state of the upper table (7), and sets the bending state of the lower table (5) along the inclined state of the upper table (7), and performs local bending in which the pressurizing range for pressurizing the workpiece (W) is limited in comparison with the pressurizing range in which the entire region in the left-right direction (X) of the upper die (8) and the lower die (6) is used. The control device (30) switches the combination of the inclined state of the upper table (7) and the bending state of the lower table (5), and repeatedly performs local bending while shifting a limited pressurizing range, thereby performing whole-area bending for pressurizing the whole area of the workpiece (W) in the left-right direction (X).

Description

Bending machine and bending method

Technical Field

The present disclosure relates to a bending machine and a bending method.

Background

A bending machine is known in which a plate-like workpiece is bent by pressing the workpiece between an upper die and a lower die by relatively moving an upper table with respect to a lower table. In the case of bending, a pressing reaction force acts on the upper table and the lower table via the workpiece held by the upper die and the lower die. The pressurizing reaction force causes flexural deformation in the upper table and the lower table, and uniformity accuracy of the workpiece is lowered. Here, the uniformity accuracy refers to the accuracy of the bending angle of the workpiece in the direction along the bending line of the workpiece.

For example, patent document 1 proposes a bending machine having a convex surface processing mechanism for correcting deflection of a lower table in the center of the lower table, in addition to a left and right lifting mechanism for lifting and lowering an upper table. According to this bending machine, the center portion of the lower table is bent to a convex shape toward the upper side by the convex processing means, whereby the deflection of the lower table is offset, and the uniformity accuracy of the workpiece can be improved.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 5-329549

Disclosure of Invention

However, according to a bending method such as bending a workpiece having a long bending line extending over the entire region of the table, sufficient uniformity accuracy may not be obtained over the entire region of the workpiece in the lateral direction.

The bending machine according to one embodiment of the present disclosure includes: a movable table to which a first mold is attached in the left-right direction; and a fixed table which is disposed to face the movable table in the vertical direction and to which a second die is attached in the horizontal direction, wherein the movable table is moved in the vertical direction to press a workpiece between the first die and the second die, thereby performing bending of the workpiece, the fixed table comprising: a lifting mechanism for moving the movable table in the up-down direction and freely adjusting the tilting state of the movable table, which is the tilting state of the movable table; a convexity processing mechanism that bends a part of the fixed table; and a control device that controls the lifting mechanism and the convex processing mechanism, wherein the control device sets the tilt state of the movable table, sets the bending state of the fixed table so as to follow the tilt state of the movable table, and performs local bending in which the pressurizing range for pressurizing the workpiece is limited in comparison with the pressurizing range in which the entire area in the left-right direction of the first die and the second die is used. The control device may repeat the local bending while shifting the limited pressurizing range by switching a combination of the inclined state of the movable table and the bending state of the fixed table, thereby bending the entire area pressurizing the workpiece over the entire area in the lateral direction.

According to this structure, the entire region of the bending line of the workpiece is not pressurized at a time, but a limited pressurizing range is pressurized. In this case, the movable table is tilted according to the pressurizing range, and the fixed table is bent along the tilted state, whereby the bending of the table in the pressurizing range can be suppressed. Since the deflection of the table in the pressurizing range is suppressed, the distance between the front end portion of the first die and the front end portion of the second die at the time of pressurizing can be kept constant. As a result, the bending angle can be made uniform over the entire area of the pressurizing range in which the mold is pressurized. Further, by shifting the pressurizing range by repeating the local bending, the workpiece can be pressurized over the entire area in the left-right direction. At this time, since the bending angle is ensured in each pressurizing range in which the partial bending is performed, the bending angle of the entire region in the left-right direction of the workpiece can be made uniform by bending the entire region.

According to one aspect of the present disclosure, a sufficient uniformity accuracy can be obtained over the entire area of the workpiece in the left-right direction.

Drawings

Fig. 1 is an explanatory diagram schematically showing the structure of the bending machine according to the present embodiment.

Fig. 2 is an explanatory diagram showing a first step of a bending operation performed by the bending machine.

Fig. 3 is an explanatory diagram showing a second step of the bending operation performed by the bending machine.

Fig. 4 is an explanatory diagram showing a third step of the bending operation performed by the bending machine.

Fig. 5 is an explanatory diagram showing a fourth step of the bending operation performed by the bending machine.

Fig. 6 is an explanatory diagram showing a fifth step of the bending operation performed by the bending machine.

Fig. 7 is an explanatory diagram showing a sixth step of the bending operation performed by the bending machine.

Fig. 8 is an explanatory diagram showing a seventh step of the bending operation performed by the bending machine.

Fig. 9 is an explanatory diagram showing an eighth step of the bending operation performed by the bending machine.

Fig. 10 is an explanatory view showing a ninth step of the bending operation performed by the bending machine.

Fig. 11 is an explanatory view showing a tenth step of a bending operation performed by the bending machine.

Fig. 12 is an explanatory view showing an eleventh step of the bending operation performed by the bending machine.

Fig. 13 is an explanatory diagram showing an angle measurement point on a workpiece.

Fig. 14 is a diagram showing an input screen for inputting an angle measurement result.

Fig. 15 is an explanatory diagram showing an example of a workpiece to be processed.

Fig. 16 is an explanatory diagram showing an operation of pressurizing the workpiece alternately left and right.

Fig. 17 is an explanatory diagram showing an operation of pressurizing the workpiece alternately left and right.

Detailed Description

The bending machine and the bending method according to the present embodiment will be described below with reference to the drawings.

Fig. 1 is an explanatory diagram schematically showing the structure of the bending machine according to the present embodiment. In the following description, the left-right direction X, the front-rear direction Y, and the up-down direction Z are used to define the bending machine. The left-right direction X and the front-rear direction Y correspond to two directions orthogonal to each other in the horizontal direction, and the up-down direction Z corresponds to the vertical direction. However, these directions are merely convenient for describing the bending machine in the present embodiment.

The bending machine 1 of the present embodiment includes: an upper table 7 (an example of a movable table) to which an upper die 8 (an example of a first die) is attached in the left-right direction X; and a lower table 5 (an example of a fixed table) disposed opposite to the upper table 7 in the up-down direction Z, and to which the lower die 6 is attached along the left-right direction X. The bending machine 1 performs bending of a workpiece by moving the upper table 7 in the up-down direction Z and pressurizing the workpiece between the upper die 8 and the lower die 6.

The bending machine 1 includes: hydraulic cylinders 9L, 9R (an example of a lifting mechanism) that move the upper table 7 in the up-down direction Z and freely adjust the tilting state, i.e., the tilting state of the upper table 7; eccentric shaft units 19L, 19R (an example of a convex surface processing mechanism) for bending a part of the lower table 5; and a control device 30 that controls the hydraulic cylinders 9L, 9R and the eccentric shaft units 19L, 19R. The control device 30 sets the inclined state of the upper table 7, and sets the curved state of the lower table 5 so as to follow the inclined state of the upper table 7, and performs local bending in which the pressurizing range is limited as compared with the pressurizing range when the workpiece is pressurized using the entire area of the left-right direction X of the upper die 8 and the lower die 6. The control device 30 switches between the combination of the inclined state of the upper table 7 and the curved state of the lower table 5, and repeatedly performs local bending while shifting the limited pressurizing range, thereby performing bending of the entire area pressurizing the workpiece W in the entire area in the left-right direction X.

The following describes the detailed structure of the bending machine 1. The bending machine 1 is a machine that performs bending of a plate-like workpiece such as a metal plate, for example. The bending machine 1 is, for example, a plate bending machine, and performs bending of a workpiece by cooperation of an upper die 8 such as a punch and a lower die 6 such as a die.

The bending machine 1 includes a lower table 5, an upper table 7, left and right hydraulic cylinders 9L, 9R, left and right eccentric shaft units 19L, 19R, and a control device 30.

The bending machine 1 has left and right side frames 3L, 3R provided separately in the left-right direction X. The upper table 7 extends in the left-right direction X and is supported on the front upper portions of the side frames 3L and 3R. The upper table 7 is configured to be movable in the up-down direction Z. The lower table 5 extends in the left-right direction X and is supported by the front lower portions of the side frames 3L and 3R.

An upper die holder for removably holding the upper die 8 is provided below the upper table 7. The upper die holder is formed with a holder groove for inserting the base portion of the upper die 8 along the left-right direction X. The upper die holder has a clamping mechanism for fixing the upper die 8 relative to the upper table 7.

A lower die holder for detachably holding the lower die 6 is provided above the lower table 5. A bracket groove for inserting the base of the lower die 6 is formed in the lower die bracket along the left-right direction X. The lower die holder has a clamping mechanism for fixing the lower die 6 relative to the lower table 5.

The left and right hydraulic cylinders 9L, 9R are provided at left and right upper portions of the side frames 3L, 3R, respectively. The left and right hydraulic cylinders 9L, 9R function as a lifting mechanism that moves the upper table 7 in the up-down direction Z. The left and right hydraulic cylinders 9L, 9R can be controlled independently. By independently controlling the left and right hydraulic cylinders 9L, 9R, the tilting state, i.e., the tilting state of the upper table 7 can be adjusted. The lifting mechanism is not limited to a structure using hydraulic cylinders 9L and 9R disposed in the left and right directions, and may be constituted by an electric motor or the like disposed in the left and right directions.

The tilting state of the upper table 7 includes a tilting state of tilting downward and leftward and a tilting state of tilting downward and rightward. The leftward downward tilting state refers to a tilting state in which the left side of the upper table 7 is closer to the lower table 5 than the right side thereof, and in the present embodiment, refers to a tilting state in which the left side of the upper table 7 is tilted downward than the right side thereof. On the other hand, the downward right inclined state refers to an inclined state in which the right side of the upper table 7 is closer to the lower table 5 than the left side thereof, and in the present embodiment, the right side of the upper table 7 is inclined downward than the left side thereof. The downward-left inclined state means that the upper table 7 may be inclined downward from the left side to the right side, and the degree (angle) of inclination of the upper table 7 with respect to the horizontal may be arbitrarily set in the movable range of the upper table 7. The same applies to the inclined state in the lower right direction.

The tilting state of the upper table 7 includes not only a state of tilting to either one of the right and left but also a basic posture of the upper table 7. The basic posture of the upper table 7 is a state in which the left side of the upper table 7 is the same as the right side thereof and the upper table 7 is horizontal.

A front plate 11 and a rear plate 13 are provided on the front side and the rear side of the lower table 5, respectively. The front plate 11 and the rear plate 13 are integrally attached to the lower table 5 via left and right pivots 15L, 15R penetrating in the front-rear direction Y.

Left and right through holes 17L, 17R penetrating the front plate 11, the lower table 5, and the rear plate 13 in the front-rear direction Y are provided at symmetrical positions in the left-right direction with respect to the center position of the lower table 5 in the left-right direction X. Left and right eccentric shaft units 19L, 19R are provided in the left and right through holes 17L, 17R. The left eccentric shaft unit 19L is disposed closer to the center of the lower table 5 than the left hydraulic cylinder 9L is when viewed in the left-right direction X. Similarly, the right eccentric shaft unit 19R is disposed closer to the center of the lower table 5 than the right hydraulic cylinder 9R is, as viewed in the left-right direction X.

The eccentric shaft units 19L, 19R are fixed to the front plate 11 and the rear plate 13. The eccentric shaft units 19L and 19R can press the lower table 5 upward with respect to the front plate 11 and the rear plate 13 by rotating the eccentric shafts. The eccentric shaft units 19L and 19R function as convex surface processing means for bending a part of the lower table 5 upward into a convex shape by pressing the lower table 5 upward. The convex surface working mechanism is not limited to a configuration using the eccentric shaft units 19L and 19R arranged in the left-right direction, and may be configured by a hydraulic cylinder or the like arranged in the left-right direction.

The left and right eccentric shaft units 19L, 19R can be controlled independently. By independently controlling the left and right eccentric shaft units 19L, 19R, the bending state of the lower table 5 can be adjusted. The adjustment of the bending state includes adjustment of the position, the shape, the degree of bending, and the like of bending the lower table 5, such as the left side, the center, and the right side. That is, by independently controlling the left and right eccentric shaft units 19L, 19R, the curved shape of the lower table 5 can be made to be a laterally symmetrical shape or a laterally asymmetrical shape.

The control device 30 includes, for example, a computer such as a numerical control machine (NC (Numerical Control: numerical control) device). The computer is composed mainly of a hardware processor such as a CPU (Central Processing Unit: central processing unit), a memory, and various interfaces. The memory and various interfaces are connected to the hardware processor via a bus. A predetermined computer program is installed in the computer. The computer executes the computer program by the hardware processor, and the computer executes the functions provided in the control device 30.

The control device 30 controls the operation of the bending machine 1. Specifically, the control device 30 controls the left and right hydraulic cylinders 9L, 9R and the left and right eccentric shaft units 19L, 19R. The control device 30 can control the movement of the upper table 7 in the up-down direction Z, the inclined state of the upper table 7, and the bent state of the lower table 5 by controlling the left and right hydraulic cylinders 9L, 9R and the left and right eccentric shaft units 19L, 19R.

In the bending machine 1 having such a configuration, the plate-like work is positioned on the lower die 6 attached to the lower table 5. The control device 30 lowers the upper table 7 toward the lower table 5. Thereby, the work is pressed between the upper die 8 and the lower die 6, and the work is bent at a desired target bending angle by cooperation of the upper die 8 and the lower die 6.

As one of the features of the present embodiment, the control device 30 sets the inclined state of the upper table 7, and sets the curved state of the lower table 5 so as to follow the inclined state of the upper table 7. The control device 30 performs local bending in which the workpiece is pressurized in a pressure range limited by the pressure range when the workpiece is pressurized in comparison with the entire region in the lateral direction X using the upper die 8 and the lower die 6.

The control device 30 switches between the combination of the inclined state of the upper table 7 and the curved state of the lower table 5, and repeatedly performs local bending while shifting the limited pressurizing range, thereby performing bending of the entire area pressurizing the workpiece W in the entire area in the left-right direction X. Then, the control device 30 repeatedly performs bending of the entire region a plurality of times, and stepwise bends the workpiece until the target bending angle is reached.

The bending method according to the present embodiment, that is, the bending operation performed by the bending machine 1 will be described below.

Fig. 2 is an explanatory diagram showing a first step of a bending operation performed by the bending machine. At the start of the bending operation, the upper table 7 is positioned at the top dead center Ht, and the inclined state thereof is set to be horizontal. The left and right hydraulic cylinders 9L, 9R can move the upper table 7 in the up-down direction Z within a range from the top dead center Ht to the bottom dead center Hb. The top dead center Ht is a point at which the upper table 7 is separated from the lower table 5 by a predetermined distance, and the bottom dead center Hb is a point at which the upper table 7 is closest to the lower table 5.

As shown in fig. 2, the control device 30 moves the upper table 7 downward while maintaining the horizontal tilt state.

Fig. 3 is an explanatory diagram showing a second step of the bending operation performed by the bending machine. When the upper table 7 reaches the reference position H1, the control device 30 sets the upper table 7 to a tilted state to the lower left. As a method of switching the upper table 7 to the lower left inclined state, for example, the left hydraulic cylinder 9L is lowered and the right hydraulic cylinder 9R is raised.

From the standpoint of setting the inclined state of the upper table 7 before the upper table 7 reaches the bottom dead center Hb, the reference position H1 is set at a position above the bottom dead center Hb. The reference position H1 includes: a speed switching position (1) for switching the lowering speed of the upper table 7, (2) a position (so-called pin point) where the tip end portion of the upper die 8 abuts against the workpiece W, (3) a position where the workpiece W is pressed between the upper die 8 and the lower die 6 so that the bending angle of the workpiece W reaches a predetermined reference angle, and the like. The reference angle is an angle for determining that the workpiece W is bent by a predetermined amount, and is set to be larger than the target bending angle.

Fig. 4 is an explanatory diagram showing a third step of the bending operation performed by the bending machine. The control device 30 lowers the upper table 7 while maintaining the downward leftward inclination, and pressurizes the workpiece W between the upper table 7 and the lower table 5. Since the upper table 7 is set in a state inclined leftward and downward, the left region of the upper die 8 first touches the left region of the workpiece W. The center and right regions of the upper die 8 are separated from the center and right regions of the workpiece W. Therefore, only the limited pressing range (hereinafter referred to as "left pressing range") La located on the left side of the workpiece W is locally pressed. The left pressurizing range La is a range narrower than a pressurizing range (a bending range of the workpiece W in the left-right direction X) in which the workpiece W is pressurized using the entire area of the left-right direction X of the upper die 8 and the lower die 6. For example, the left pressurizing range La is a range of about 1/3 of the length (the total length of the bending line) of the entire region in the left-right direction X of the workpiece W.

Fig. 5 is an explanatory diagram showing a fourth step of the bending operation performed by the bending machine. Since the upper table 7 is inclined downward and leftward, the left region in the left pressurizing range La is bent at a larger angle than the right region. Therefore, the control device 30 sets the bending state of the lower table 5 so as to follow the tilting state of the upper table 7 in order to eliminate the deviation of the bending angle in the left pressurizing range La. Specifically, control device 30 sets the bending state of lower table 5 so that the left side of lower table 5 is inclined leftward and downward along upper table 7. For example, the control device 30 bends a portion of the lower table 5 on the left side of the center into a convex shape. However, the bending state of the lower table 5 is not limited to this, as long as the left side of the lower table 5 is inclined downward and leftward along the upper table 7. The control device 30 controls one or both of the left and right eccentric shaft units 19L, 19R to set the bending state of the lower table 5.

In the present embodiment, the control device 30 sets the bending state of the lower table 5 after the upper table 7 pressurizes the workpiece W. However, the control device 30 may set the bending state of the lower table 5 before the upper table 7 pressurizes the workpiece W. However, when the bending state of the lower table 5 is set in advance, there is a possibility that the position of the workpiece W is shifted due to the bending of the lower table 5. Therefore, it is preferable to set the bending state of the lower table 5 in a state where the upper table 7 pressurizes the workpiece W to fix the workpiece W.

Fig. 6 is an explanatory diagram showing a fifth step of the bending operation performed by the bending machine. When the upper table 7 is lowered to the bottom dead center Hb by continuing the lowering of the upper table 7, not only the left side of the workpiece W but also the entire area of the workpiece W in the left-right direction X is pressurized. Therefore, the control device 30 raises the upper table 7 before the entire area of the workpiece W in the lateral direction X is pressurized, that is, before the upper table 7 reaches the bottom dead center Hb. Thereby, the pressure applied to the workpiece W is reduced.

The control device 30 releases the bending state of the lower table 5 in response to the decompression, and adjusts the entire area of the lower table 5 in the lateral direction X to be flat.

When the upper table 7 is raised by the pressure removal, the workpiece W may be deviated if the upper table 7 is greatly raised. Therefore, the control device 30 preferably lifts the upper table 7 with the position at which the rebound of the workpiece W ends as an upper limit. By raising the upper table 7 in such a range, the state where the workpiece W is in contact with the upper die 8 can be maintained, and therefore, positional displacement of the workpiece W can be suppressed.

The position at which the rebound of the workpiece W ends is a position at which the upper table 7 is raised to gradually release the pressure on the workpiece W, and the pressure is substantially 0. The position at which the rebound ends can be determined from (1) known information calculated from the machining conditions, (2) pressure values of the left and right hydraulic cylinders 9L, 9R, (3) a measured value of the bending angle of the workpiece W obtained by an angle sensor or the like, and the like.

When the upper table 7 is raised, the control device 30 is raised in parallel while maintaining the inclined state of the upper table 7 at the time of pressurization, that is, while maintaining the inclined state of the lower left. By ascending in parallel while maintaining the inclined state of the upper table 7, the load acting on the left pressurizing range La can be equally released. Therefore, uniformity accuracy in the left pressurizing range La can be improved.

Fig. 7 is an explanatory diagram showing a sixth step of the bending operation performed by the bending machine. When the pressurization and the depressurization within the leftward pressurization range La are completed, the control device 30 sets the upper table 7 to a horizontally tilted state. As a method of switching from the tilting state to the left-lower tilting state to the horizontal tilting state, for example, the left hydraulic cylinder 9L is raised and the right hydraulic cylinder 9R is lowered.

Fig. 8 is an explanatory diagram showing a seventh step of the bending operation performed by the bending machine. The control device 30 lowers the upper table 7 while maintaining the horizontal tilt state, and pressurizes the workpiece W between the upper table 7 and the lower table 5.

Fig. 9 is an explanatory diagram showing an eighth step of the bending operation performed by the bending machine. When the workpiece W is pressurized in a state where only the upper table 7 is lowered, the entire area of the workpiece W in the lateral direction X is pressurized. Accordingly, the control device 30 sets the bending state of the lower table 5 so as to locally press a limited pressing range Lb located at the center of the workpiece W (hereinafter referred to as "central pressing range") together with the pressing of the upper table 7. Specifically, control device 30 sets the bent state of lower table 5 so that the center of lower table 5 is bent upward in a convex shape. The control device 30 controls one or both of the left and right eccentric shaft units 19L, 19R to set the bending state of the lower table 5.

The upper table 7 is set in a horizontally inclined state, but the center of the lower table 5 is bent upward. Therefore, the central region of the upper die 8 first hits the central region of the workpiece W. The left and right regions of the upper die 8 are separated from the left and right regions of the workpiece W. Therefore, only the central pressurizing range Lb is locally pressurized. The central pressurizing range Lb is a range narrower than a pressurizing range (a bending range of the workpiece W in the left-right direction X) in which the workpiece W is pressurized using the entire area of the left-right direction X of the upper die 8 and the lower die 6. For example, the length (the total length of the bending line) of the entire area of the limited pressurizing range Lb in the left-right direction X of the workpiece W is about 1/3.

In order to eliminate the deviation of the bending angle in the central pressing range Lb, the control device 30 sets the bending state of the lower table 5 so as to follow the inclined state of the upper table 7, for example, as in a trapezoid shape with a flat upper bottom.

Fig. 10 is an explanatory view showing a ninth step of the bending operation performed by the bending machine. When the upper table 7 is lowered to the bottom dead center Hb by continuing the lowering of the upper table 7, not only the center of the workpiece W but also the entire area of the workpiece W in the lateral direction X is pressurized. Therefore, the control device 30 raises the upper table 7 before the entire area of the workpiece W in the lateral direction X is pressurized, that is, before the upper table 7 reaches the bottom dead center Hb. Thereby, the pressure applied to the workpiece W is reduced. The method of raising the upper table 7 to perform the pressure removal is as described above.

The control device 30 releases the bending state of the lower table 5 in response to the decompression, and adjusts the entire area of the lower table 5 in the lateral direction X to be flat.

Fig. 11 is an explanatory view showing a tenth step of a bending operation performed by the bending machine. The control device 30 sets the upper table 7 to a downward right inclined state. As a method of setting the upper table 7 to a downward right inclined state, for example, the right hydraulic cylinder 9R is lowered and the left hydraulic cylinder 9L is raised.

Fig. 12 is an explanatory view showing an eleventh step of the bending operation performed by the bending machine. The control device 30 lowers the upper table 7 while maintaining the downward right inclination, and pressurizes the workpiece W between the upper table 7 and the lower table 5. Since the upper table 7 is set in a state inclined rightward and downward, the right region of the upper die 8 first touches the right region of the workpiece W. The left and center regions of the upper die 8 are separated from the left and center regions of the workpiece W. Therefore, only the limited pressing range Lc located on the right side of the workpiece W (hereinafter referred to as "right-side pressing range") is locally pressed. The right pressurizing range Lc is a range narrower than a pressurizing range (a bending range of the workpiece W in the left-right direction X) in which the workpiece W is pressurized using the entire area of the left-right direction X of the upper die 8 and the lower die 6. For example, the pressing range Lc on the right side is about 1/3 of the length (the total length of the bending line) of the entire region in the left-right direction X of the workpiece W.

In order to eliminate the deviation of the bending angle in the right pressurizing range Lc, the control device 30 sets the bending state of the lower table 5 so as to follow the tilting state of the upper table 7. Specifically, the control device 30 sets the bending state of the lower table 5 so that the right side of the lower table 5 corresponding to the limited pressurizing range Lc is inclined rightward and downward along the upper table 7. For example, the control device 30 bends a portion of the lower table 5 on the right side of the center into a convex shape. However, the inclination state in which the right side of the lower table 5 is inclined downward to the right along the upper table 7 is not limited thereto. The control device 30 controls one or both of the left and right eccentric shaft units 19L, 19R to set the bending state of the lower table 5.

In this way, the control device 30 switches the combination of the inclined state of the upper table 7 and the curved state of the lower table 5, and repeatedly performs the pressurizing operation (local bending) for the three pressurizing ranges La, lb, lc. Thereby, the control device 30 bends the entire area of the workpiece W in the lateral direction X by pressurizing the entire area.

The control device 30 repeatedly performs bending of the entire region a plurality of times, and stepwise bends the workpiece W until the target bending angle is reached. Then, when the workpiece W is bent to the target bending angle, the bending processing of the workpiece W is ended.

Next, a method of determining the outputs of the left and right hydraulic cylinders 9L, 9R and the outputs of the left and right eccentric shaft units 19L, 19R when pressurizing the respective pressurizing ranges La, lb, lc will be described with reference to fig. 13 and 14. Fig. 13 is an explanatory diagram showing an angle measurement point of a workpiece. Fig. 14 is a diagram showing an input screen for inputting the angle measurement result.

The outputs of the left and right hydraulic cylinders 9L, 9R are control parameters corresponding to the amount of press-in of the upper table 7 and the amount of tilting of the upper table 7. The press-in amount of the upper table 7 is an amount of lowering of the upper table 7 required to obtain a predetermined bending angle from the pin point. The outputs of the left and right eccentric shaft units 19L, 19R are control parameters corresponding to the bending position, bending shape, and bending size of the lower table 5.

First, the control device 30 temporarily determines the outputs of the left and right hydraulic cylinders 9L, 9R and the outputs of the left and right eccentric shaft units 19L, 19R for the respective pressurizing ranges La, lb, lc according to the bending conditions of the workpiece W, that is, the plate thickness, the material, the length of the bending line, and the like.

The operator prepares the work W for trial bending. Under the control of the control device 30, the combination of the inclined state of the upper table 7 and the curved state of the lower table 5 is switched for each of the pressure ranges La, lb, lc, and the pressure operation (local bending) is repeatedly performed for each of the pressure ranges La, lb, lc. Thereby, the entire region (the entire region of the bending line) of the workpiece W in the left-right direction X is pressurized (the entire region is bent).

Then, as shown in fig. 13, the bending angle of the workpiece W is measured at each of the angle measurement points M1 to M4. The angle measurement point M1 is a point at the left end of the workpiece W, that is, a point at the left end of the left pressurizing range La. The angle measurement point M2 is a point at the right end of the left pressurizing range La and the left end of the center pressurizing range Lb. The angle measurement point M3 is a point at the right end of the center pressing range Lb and the left end of the left pressing range Lc. The angle measurement point M4 is a point at the right end of the workpiece W, that is, a point at the right end of the pressing range Lc on the right side. Thus, the four angle measurement points M1 to M4 are located at the boundaries of the respective pressurizing ranges La, lb, lc.

The bending angle at each of the angle measurement points M1 to M4 can be manually measured by the operator himself/herself using an angle sensor. Further, the control device 30 may automatically measure the bending angle at each of the angle measurement points M1 to M4 by operating the angle sensor mounted on the bending machine 1 by a predetermined operation of the operation panel 35 (see fig. 14) by the operator.

When the operator manually measures the bending angle, the operator inputs the measured values of the bending angle at the angle measurement points M1 to M4 to the operation panel, and the control device 30 can obtain information thereof. In addition, when the control device 30 automatically measures the bending angle, the control device 30 can directly obtain the measured values of the bending angle at the respective angle measurement points M1 to M4 from the angle sensor.

In this way, the bending angles measured at the respective angle measurement points M1 to M4 are input to the control device 30. As shown in fig. 14, control device 30 displays the measured values of the bending angles of each of angle measurement points M1 to M4 on predetermined display screen 36 of operation panel 35. In the display screen 36, four display items 36a to 36d for displaying the measured values of the bending angles at the angle measurement points M1 to M4 are prepared.

The control device 30 performs necessary calculation for each of the three pressurizing ranges La, lb, lc based on the bending angles measured at the respective angle measurement points M1 to M4.

Specifically, the control device 30 corrects the outputs of the left and right hydraulic cylinders 9L, 9R and the outputs of the left and right eccentric shaft units 19L, 19R when pressurizing the left pressurizing range La, using the bending angles obtained from the three angle measurement points M1 to M3. At this time, control device 30 corrects the outputs of left and right hydraulic cylinders 9L, 9R based on angle measurement points M1, M3, and corrects the outputs of left and right eccentric shaft units 19L, 19R based on angle measurement point M2.

Similarly, the control device 30 corrects the outputs of the left and right hydraulic cylinders 9L, 9R and the outputs of the left and right eccentric shaft units 19L, 19R when pressurizing the central pressurizing range Lb, using the bending angles obtained from the four angle measurement points M1 to M4. At this time, control device 30 corrects the output of left hydraulic cylinder 9L based on angle measurement point M1, and corrects the output of right hydraulic cylinder 9R based on angle measurement point M4. The control device 30 corrects the output of the left eccentric shaft unit 19L based on the angle measurement point M2, and corrects the output of the right eccentric shaft unit 19R based on the angle measurement point M3.

The control device 30 corrects the outputs of the left and right hydraulic cylinders 9L and 9R and the outputs of the left and right eccentric shaft units 19L and 19R when pressurizing the right pressurizing range Lc using the three bending angles at the angle measurement points M2 to M4. At this time, control device 30 corrects the outputs of left and right hydraulic cylinders 9L, 9R based on angle measurement points M2, M4, and corrects the outputs of left and right eccentric shaft units 19L, 19R based on angle measurement point M3.

When the correction is performed in this way, the control device 30 controls the left and right hydraulic cylinders 9L and 9R and the left and right eccentric shaft units 19L and 19R based on the corrected output. This makes it possible to pressurize the workpiece W at an appropriate output.

In the above description, the pressurizing operation (partial bending) is repeated for the three pressurizing ranges La, lb, lc for the workpiece W for trial bending before the angle measurement, whereby the entire region of the workpiece W in the left-right direction X is pressurized (the entire region is bent). However, the bending angle of the workpiece W at this time may be measured by pressing the entire area of the workpiece W at one time while the upper table 7 is kept in a horizontally inclined state.

As described above, in the bending machine 1 of the present embodiment, the control device 30 sets the inclined state of the upper table 7, and sets the curved state of the lower table 5 so as to follow the inclined state of the upper table 7, and performs local bending in which the pressurizing ranges La, lb, lc, in which the pressurizing ranges for pressurizing the workpiece W are limited, are smaller than the pressurizing ranges for pressurizing the workpiece W using the entire regions of the upper die 8 and the lower die 6 in the left-right direction X. The control device 30 switches between the combination of the inclined state of the upper table 7 and the curved state of the lower table 5, and repeatedly performs the local bending while shifting the defined pressurizing ranges La, lb, lc, thereby performing the bending of the entire area pressurizing the workpiece W in the entire area in the left-right direction X.

According to the bending machine 1 of the present embodiment, the following first effect is achieved. That is, according to the bending machine 1 of the present embodiment, the entire region of the workpiece W (the bending line of the workpiece W) is not pressurized at a time, but the limited pressurizing ranges La, lb, lc are pressurized. At this time, the upper table 7 is inclined according to the pressurizing ranges La, lb, lc, and the lower table 5 is bent so as to follow the inclined state, whereby the bending of the tables in the pressurizing ranges La, lb, lc can be suppressed. Since the deflection of the table in the pressurizing ranges La, lb, lc is suppressed, the distance between the lower end portion of the upper die 8 and the upper end portion of the lower die 6 at the time of pressurizing can be kept constant. As a result, the bending angles can be made uniform in the entire areas of the pressing ranges La, lb, lc in which the upper die 8 and the lower die 6 are pressed, and therefore uniformity accuracy can be improved in the pressing ranges La, lb, lc.

For example, even if the tilt state of the upper table 7 is switched for each of the pressing ranges La, lb, lc, when the bending state of the lower table 5 is fixed, the bending state of the lower table 5 may not coincide with the tilt state of the upper table 7. Similarly, even if the bending state of the lower table 5 is switched for each of the pressing ranges La, lb, lc, when the tilting state of the upper table 7 is fixed, the bending state of the lower table 5 may not coincide with the tilting state of the upper table 7. In this case, the distance between the lower end portion of the upper die 8 and the upper end portion of the lower die 6 varies. Therefore, as shown in the present embodiment, it is important to set the inclined state of the upper table and the curved state of the lower table 5 along the inclined state according to the pressurizing ranges La, lb, lc.

Further, by repeating the partial bending to shift the pressing ranges La, lb, lc, the workpiece W can be pressed over the entire area in the left-right direction X. At this time, since the bending angle is ensured in each of the pressing ranges La, lb, lc in which the partial bending is performed, the bending angle can be made uniform in the entire region of the workpiece W in the left-right direction X by bending the entire region. This can obtain a sufficient uniformity accuracy over the entire area of the workpiece W in the lateral direction X.

Further, according to the bending machine 1 of the present embodiment, the following second effect is also achieved. First, a bending method is considered in which the upper table 7 is lowered in a horizontally inclined state, and the workpiece W is pressurized over the entire area in the horizontal direction X of the upper die 8 and the lower die 6. In the case of this bending method, the entire area of the workpiece W in the lateral direction X is pressurized by receiving a bending load from the upper table 7. About 1/3 of the load applied from the upper table 7 acts on the region corresponding to the left pressurizing range La shown in fig. 4. On the other hand, as shown in the present embodiment, when only the left pressurizing range La is locally pressurized, the load applied from the upper table 7 is concentrated on the left pressurizing range La. Therefore, by pressurizing the workpiece W in the left pressurizing range La, even if the bending load is smaller than the bending load required when pressurizing the entire area of the workpiece W in the left-right direction X, the same pressure can be applied to the workpiece W. That is, the bending machine 1 can perform bending at a bending load smaller than that required when pressurizing the entire area of the workpiece W in the left-right direction X by pressurizing the left pressurizing range La.

Similarly, as shown in fig. 9, the bending machine 1 can perform bending with a bending load smaller than that required when pressurizing the entire area of the workpiece W in the lateral direction X by pressurizing the pressurizing range Lb defined in the center. As shown in fig. 12, the bending machine 1 is configured to press the entire area of the workpiece W in the left-right direction X by the pressing range Lc defined on the right side, and is capable of performing bending with a bending load smaller than that required when pressing the entire area of the workpiece W in the left-right direction X.

In this way, by utilizing the inclined state of the upper table 7 and the curved state of the lower table 5, the defined pressurizing range can be locally pressurized. In this case, the bending load applied from the upper table 7 intensively acts on the defined pressurizing ranges La, lb, lc. By pressurizing the defined pressurizing ranges La, lb, lc, even a bending load smaller than that required when pressurizing the entire area of the workpiece W in the lateral direction X can be applied to the pressurizing ranges with the same pressure (stress). That is, by pressurizing the defined pressurizing ranges La, lb, lc, the bending machine 1 can perform bending at a bending load smaller than that required when pressurizing the entire area of the workpiece W in the lateral direction X. Therefore, a desired bending process can be performed on the workpiece W without using the bending machine 1 having a high pressurizing capability.

In addition, as described above, by switching the combination of the inclined state of the upper table 7 and the curved state of the lower table 5, the defined pressurizing ranges La, lb, lc can be shifted. Thus, the entire area of the workpiece W in the lateral direction X can be appropriately pressurized without using the bending machine 1 having high pressurizing capability.

In the bending machine 1 of the present embodiment, the control device 30 repeatedly performs bending of the entire region a plurality of times, and stepwise bends the workpiece W to a target bending angle.

According to this configuration, the bending angle of the workpiece W can be made to approach the target bending angle stepwise by bending the workpiece W stepwise. This can more reliably improve uniformity accuracy. Further, even with a small bending load, the workpiece W can be bent to a target bending angle by bending the workpiece W stepwise. Thus, the workpiece W can be bent to a desired target bending angle without using the bending machine 1 having a high pressurizing capability.

In the bending machine 1 of the present embodiment, the left and right hydraulic cylinders 9L, 9R can move the upper table 7 in a range from the top dead center Ht to the bottom dead center Hb. When the upper table 7 reaches the bottom dead center Hb, the control device 30 sets the inclined state of the upper table 7.

When the entire area of the workpiece W in the lateral direction X is pressurized, the bending load is dispersed over the entire area of the workpiece W, and therefore, the pressure required for bending cannot be applied to the workpiece W. In this regard, according to the configuration of the present embodiment, since the inclined state of the upper table 7 is inclined before the upper table 7 reaches the bottom dead center Hb, it is possible to suppress the entire area of the workpiece W in the lateral direction X from being pressurized at one time. Since the workpiece W can be pressurized in the respective pressurizing ranges La, lb, lc, uniformity accuracy can be improved by the respective pressurizing ranges La, lb, lc. Further, without using the bending machine 1 having a high pressurizing capability, desired bending can be performed in the respective pressurizing ranges La, lb, lc.

In the bending machine 1 of the present embodiment, after pressurizing the workpiece W, the control device 30 moves the upper table 7 toward the top dead center Ht side in a range where the upper die 8 contacts the workpiece W by rebound of the workpiece W, and then switches a combination of the inclined state of the upper table 7 and the bent state of the lower table 5.

According to this structure, even if the upper table 7 is raised at the time of the pressure removal, the upper table 7 is raised only in a range where the upper die 8 contacts the workpiece W. Therefore, when the combination of the inclined state of the upper table 7 and the curved state of the fixed table is switched, the upper die 8 presses the workpiece W, and thus the positional displacement of the workpiece W can be suppressed. This makes it possible to bend the workpiece W with high accuracy. Uniformity accuracy can be improved by the respective pressurizing ranges La, lb, lc.

In the bending machine 1 of the present embodiment, the control device 30 moves the upper table 7 toward the top dead center Ht while maintaining the inclined state when the workpiece W is pressurized.

According to this configuration, since the upper table 7 is moved while maintaining the inclined state, the load acting on the pressurizing range can be equally released. This can improve the uniformity accuracy of the workpiece W in the respective pressurizing ranges La, lb, lc.

In the bending machine 1 of the present embodiment, the control device 30 bends the left side of the lower table 5 upward when the left side of the upper table 7 is inclined closer to the lower table 5 than the right side.

According to this structure, the left region of the workpiece W can be pressurized with high uniformity accuracy.

In the bending machine 1 of the present embodiment, the control device 30 bends the right side of the lower table 5 upward when the right side of the upper table 7 is inclined closer to the lower table 5 than the left side.

According to this structure, the right region of the workpiece W can be pressurized with high uniformity accuracy.

In the bending machine 1 of the present embodiment, when the upper table 7 is tilted horizontally, the control device 30 bends the center of the lower table 5 upward.

According to this structure, the region in the center of the workpiece W can be pressurized with high uniformity accuracy.

In the present embodiment, the lifting mechanism is composed of left and right hydraulic cylinders (an example of a lifting unit) 9L, 9R provided at the left and right end portions of the movable table and capable of being controlled independently of each other. The convex surface machining means is constituted by left and right eccentric shaft units (an example of convex surface machining units) 19L, 19R which are provided symmetrically and laterally with respect to the center position of the lower table 5 in the left and right direction X and which can be controlled independently of each other.

According to this configuration, the bending shape of the lower table 5 can be made to be a laterally symmetrical shape or a laterally asymmetrical shape by independently controlling the left and right eccentric shaft units 19L, 19R. This makes it possible to appropriately control the bending state of the lower table 5 so as to follow the inclined state of the upper table 7.

In the present embodiment, control device 30 corrects the outputs of left and right hydraulic cylinders 9L and 9R and the outputs of left and right eccentric shaft units 19L and 19R based on the bending angles obtained at four angle measurement points M1 to M4 located at the boundaries of left, center, and right pressurizing ranges La, lb, lc.

For example, it is considered to perform the output correction of the hydraulic cylinders 9L, 9R and the output correction of the left and right eccentric shaft units 19L, 19R by performing angle measurement at three points of the left, center, and right of the work W. When the correction is performed for the left pressurizing range La, the outputs of the left and right hydraulic cylinders 9L, 9R are corrected based on two points of the left and center, and the outputs of the left and right eccentric shaft units 19L, 19R are corrected based on one point of the center. In this case, the bending angle obtained at the same point (center point) is used for the output correction of the hydraulic cylinders 9L, 9R and the output correction of the left and right eccentric shaft units 19L, 19R. Therefore, it is difficult to distinguish what degree of correction is performed in which output, and a plurality of solutions may be generated.

In this regard, according to the configuration of the present embodiment, the bending angles obtained at the different angle measurement points M1 to M4 can be used in the output correction of the left and right hydraulic cylinders 9L, 9R and the output correction of the left and right eccentric shaft units 19L, 19R. For example, when the left pressurization range La is corrected, the outputs of the left and right hydraulic cylinders 9L and 9R are corrected based on the angle measurement points M1 and M3, and the outputs of the left and right eccentric shaft units 19L and 19R are corrected based on the angle measurement point M2 different from the angle measurement points M1 and M3. In this way, since different angle measurement points can be allocated to the output correction of the hydraulic cylinders 9L, 9R and the output correction of the left and right eccentric shaft units 19L, 19R, the correction value of the output can be uniquely determined. Therefore, appropriate correction can be performed.

In the above-described embodiment, the bending machine 1 having the upper table 7 corresponding to the movable table and the lower table 5 corresponding to the fixed table is exemplified. However, the bending machine may have a structure including a lower table corresponding to the movable table and an upper table corresponding to the fixed table.

In the above-described embodiment, the bending machine is configured to tilt the movable table moving in the up-down direction Z to bend the fixed table. However, the bending machine may be configured to bend a movable table that moves in the up-down direction Z and tilt a fixed table.

In the bending method according to the present embodiment, the inclined state of the movable table is set, the bending state of the fixed table is set so as to follow the inclined state of the movable table, the partial bending is performed in which the workpiece is pressurized in a pressurizing range limited by the pressurizing range when the workpiece W is pressurized in comparison with the entire region in the lateral direction X using the first die and the second die, and the entire region in which the workpiece is pressurized in the lateral direction X is bent by repeating the partial bending while shifting the limited pressurizing range by switching the combination of the inclined state of the movable table and the bending state of the fixed table.

As described above, in addition to the bending machine 1 shown in the present embodiment, the bending method of bending the workpiece W using the bending machine 1 also functions as a part of the present invention. The bending method also has the same effects as those of the bending machine 1 described above.

In the present embodiment, the pressurizing ranges are shifted in the order of the left side, the center, and the right side of the workpiece W. However, the method of shifting the pressurizing range may be any of the following: (1) left, right, and center order of the workpiece W, (2) right, center, and left order of the workpiece W, (3) right, left, and center order of the workpiece W, (4) center, left, and center order of the workpiece W, and (5) center, right, and left order of the workpiece W.

In the present embodiment, the three pressing ranges including the left side, the center, and the right side of the workpiece W are locally curved. However, the partial bending may be performed within a pressure range that is limited to a pressure range in which the workpiece W is pressed by using the entire region of the upper die 8 and the lower die 6 in the lateral direction X. For example, the two pressing ranges formed by the left half and the right half of the workpiece W may be partially curved. Further, each region on the left, center, and right sides of the workpiece W may be further divided, and the workpiece W may be locally bent in each divided pressurizing range.

Fig. 15 is an explanatory diagram showing an example of a workpiece to be processed. In the above-described embodiment, the workpiece to be processed is the workpiece W having one bending line continuous in the left-right direction. However, the workpiece to be processed may be a workpiece W1 in which the bending lines Ba, bc are biased to the left and right by providing the notch C.

Fig. 16 and 17 are explanatory views showing operations of pressurizing the workpiece alternately left and right. Even in such a workpiece W1, the bending operation is performed in the same manner as in the above-described method in each of the pressing ranges La1, lc1 corresponding to the bending lines Ba, bc. That is, the control device 30 controls the upper table 7 to be inclined leftward and downward, and controls the left-side bending state of the lower table 5 to be inclined leftward and downward along the upper table 7. In this state, the pressurizing range La1 corresponding to the bending line Ba is pressurized. Similarly, the control device 30 controls the upper table 7 to be inclined rightward and downward, and controls the right-side bending state of the lower table 5 to be inclined rightward and downward along the upper table 7. In this state, the pressurizing range Lc1 corresponding to the bending line Bc is pressurized.

In the workpiece W1 having such bending lines Ba, bc deviated to the left and right, when the upper table 7 is lowered in the inclined state of the left and right, the pressurizing reaction force does not act on the upper table 7 and the lower table 5 at the notch C. By applying uneven pressing reaction forces to the upper table 7 and the lower table 5, unnecessary deflection occurs in the upper table 7 and the lower table 5, and uniformity accuracy cannot be ensured in the bending lines Ba and Bc, respectively. In this regard, according to the present embodiment, the variation in the bending angle can be suppressed in any of the pressing ranges La1, lc 1. As a result, uniformity accuracy can be improved in the respective pressurizing ranges La1, lc 1. This can obtain a sufficient uniformity accuracy over the entire region of the workpiece W in the left-right direction X, that is, over the entire region of the bending line that is biased to the left and right.

In the present embodiment, the movable table is moved in the up-down direction Z while maintaining the inclined state at the time of performing the decompression. However, after the end of the pressurizing operation for a certain pressurizing range, the control device 30 may switch the movable table to the inclined state corresponding to the next pressurizing range without raising the movable table.

In the present embodiment, a mechanism for bending a part of a table to which a die is attached is exemplified as the convex processing mechanism. However, the bending shape may be formed in advance by a die or the like attached to the table without bending the table itself. In this specification, a structure that can obtain the same effect as bending a table by using an object attached to the table is also explained as a convex processing mechanism, in addition to a method of bending the table itself.

As noted above, embodiments of the present invention are described, but the discussion and drawings that form a part of this disclosure should not be construed as limiting the invention. Various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art in light of this disclosure.

Symbol description

The disclosure of this application is associated with the subject matter described in japanese patent application No. 2021-130572 filed at 10 at 2021 and No. 2022-125542 filed at 5 at 2022, 8, which disclosures are incorporated herein by reference in their entirety.

Claims (12)

1. A bending machine is provided with: a movable table to which a first mold is attached in the left-right direction; and a fixed table which is disposed opposite to the movable table in the up-down direction and is provided with a second mold along the left-right direction,

The movable table is moved in the up-down direction to press a workpiece between the first die and the second die, thereby performing bending of the workpiece,

the bending machine is characterized by comprising:

a lifting mechanism that moves the movable table in the up-down direction and freely adjusts a tilting state, which is a tilting state of the movable table;

a convexity processing mechanism that bends a part of the fixed table; and

a control device for controlling the lifting mechanism and the convex processing mechanism,

the control device sets the inclined state of the movable table, sets the bending state of the fixed table along the inclined state of the movable table, performs local bending in which the pressurizing range for pressurizing the workpiece is limited in comparison with the pressurizing range for pressurizing the workpiece using the entire area of the first die and the second die in the left-right direction,

the control device repeatedly performs the local bending while shifting the limited pressurizing range by switching a combination of the inclined state of the movable table and the bending state of the fixed table, thereby performing the bending of the entire area pressurizing the workpiece in the entire area in the lateral direction.

2. The bending machine according to claim 1, wherein the bending machine is configured to bend the sheet material,

the control device repeats bending of the whole area for a plurality of times, and bends the workpiece to a target bending angle in a stepwise manner.

3. A bending machine according to claim 1 or 2, wherein,

the elevating mechanism is capable of moving the movable table in a range from a top dead center at which the movable table is separated from the fixed table by a predetermined distance to a bottom dead center at which the movable table is closest to the fixed table,

in the case of performing the local bending, the control device sets the tilt state of the movable table before the movable table reaches the bottom dead center.

4. A bending machine according to claim 3, wherein,

after the local bending is performed, the control device moves the movable table toward the top dead center side in a range where the first die is in contact with the workpiece by rebound of the workpiece, and then switches a combination of a tilted state of the movable table and a bent state of the fixed table.

5. The bending machine according to claim 4, wherein the bending machine is configured to bend the sheet material,

The control device moves the movable table toward the top dead center side while maintaining an inclined state when the workpiece is pressurized in the limited pressurizing range.

6. A bending machine according to claim 1 or 2, wherein,

the control device bends the left side of the fixed table upward when the movable table is in an inclined state in which the left side of the movable table is closer to the fixed table than the right side of the movable table.

7. A bending machine according to claim 1 or 2, wherein,

the control device bends the right side of the fixed table upward when the movable table is in an inclined state in which the right side of the movable table is closer to the fixed table than the left side of the movable table.

8. A bending machine according to claim 1 or 2, wherein,

when the movable table is in a tilted state in which the left and right sides of the movable table are horizontal, the control device bends the center of the fixed table upward.

9. A bending machine according to claim 1 or 2, wherein,

The lifting mechanism is composed of left and right lifting units which are arranged at the left and right ends of the movable workbench and can be controlled independently,

the convex surface processing means is composed of left and right convex surface processing units which are symmetrically arranged on the left and right direction of the fixed table and can be controlled independently of each other.

10. The bending machine according to claim 9, wherein the bending machine is configured to bend the sheet of material,

in the case of pressurizing the work into three pressurizing ranges of the left side, the center and the right side,

the control device corrects the output of the left and right lifting units and the output of the left and right convex processing units based on the bending angles obtained at four angle measurement points located at the boundaries of each pressurizing range.

11. A bending machine is provided with: a movable table to which a first mold is attached in the left-right direction; and a fixed table which is disposed opposite to the movable table in the up-down direction and is provided with a second mold along the left-right direction,

the movable table is moved in the up-down direction to press a workpiece between the first die and the second die, thereby performing bending of the workpiece,

The bending machine is characterized by comprising:

a lifting mechanism for moving the movable table in the up-down direction;

a tilting mechanism capable of freely adjusting a tilting state, which is a tilting state of the fixed table;

a convex processing mechanism for bending a part of the movable table; and

a control device for controlling the lifting mechanism, the tilting mechanism and the convex processing mechanism,

the control device sets the inclined state of the fixed table, sets the bending state of the movable table along the inclined state of the fixed table, performs local bending in which the pressurizing range is limited compared with the pressurizing range when the whole area of the left and right directions of the first die and the second die is used for pressurizing the workpiece,

the control device repeatedly performs the local bending while shifting the limited pressurizing range by switching a combination of the inclined state of the fixed table and the bending state of the movable table, thereby performing the bending of the entire area pressurizing the workpiece in the entire area in the lateral direction.

12. A bending method for a workpiece by pressing the workpiece between a first die and a second die by moving a movable table in the up-down direction, the bending machine comprising: the movable table is provided with the first mold along the left-right direction; and a fixed table disposed opposite to the movable table in the vertical direction, the fixed table being provided with the second mold along the horizontal direction,

The bending method is characterized in that,

setting an inclined state of the movable table;

the bending state of the fixed table is set in such a manner as to follow the inclined state of the movable table,

performing local bending in which a pressurizing range is limited in comparison with a pressurizing range when pressurizing a workpiece using the entire region in the lateral direction of the first die and the second die; and

by switching the combination of the inclined state of the movable table and the curved state of the fixed table, the local bending is repeatedly performed while shifting the limited pressurizing range, and the entire region where the workpiece is pressurized in the lateral direction is bent.