JP2000343126A - Press brake crowning method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press brake crowning method and a device therefor which eliminates the need for controlling a hydraulic pressure of a crowning cylinder. SOLUTION: A work W bend processing is performed with a co-working of a punch P and a die D mounted on upper, bottom tables 5, 7 of a press brake 1. Crowning cylinders 21, 23 are provided with a cutout part 19 being set-up at nearly a center in left, right direction of the bottom table 7 for adjusting a deflection volume of the bottom table 7. The crowning cylinders 21, 23 and adjusting cylinders 25, 27 which are connected through via hydraulic pipe routes 33 are provided between the left, right end parts of the bottom table 7 and left and right side frames 9, 11. Pressing force being applied to the bottom table 7 at a bend processing time pressurizes the adjusting cylinders 25, 27 and oil in the adjusting cylinders 25, 27 is flowed in the crowning cylinders 21, 23 from the hydraulic pipe route 33. Proper crowning operation is thus automatically performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for crowning press brakes.

[0002]

2. Description of the Related Art Conventionally, as a press brake with a hydraulic crowning, for example, as shown in FIG. 5, in a descending hydraulic press brake 101, a left shaft and a right shaft are provided above left and right side frames 103 and 105. Hydraulic cylinders 107 and 109 are provided, and piston rods 111 of these left and right axis hydraulic cylinders 107 and 109 are provided.
An upper table 113 is connected to the lower end of the table and is provided to be vertically movable.

Also, left and right side frames 103, 10
The lower table 115 is fixed to the lower portion of the lower table 5, and a notch 117 is provided near the center of the lower table 115. The notch 117 includes, for example, crowning cylinders 119 and 121 (a hydraulic cylinder) as a crowning device. ) Are provided.

A punch P is mounted on the lower surface of the upper table 113, and a die D is mounted on the upper surface of the lower table 115. Therefore, the upper table 113 moves up and down, and the plate material W is bent in cooperation with the punch P and the die D. At this time, the crowning cylinders 119 and 121
Is controlled by the control device 123 to adjust the amount of deflection of the lower table 115 at the center.

[0005]

By the way, in the conventional press brake 101 with hydraulic crowning,
A hydraulic supply source that supplies pressure oil for driving the left and right axis hydraulic cylinders 107 and 109 and the crowning cylinders 119 and 121 is required. When bending the work W, trial bending is performed using the same material as the product in advance, and bending conditions are set. Under the same processing conditions, the hydraulic pressure is controlled by the control device 123 and the product is manufactured. Bending is being performed.

The above-described left and right axis hydraulic cylinders 107,
In order to appropriately control the hydraulic pressures of the cylinders 109 and the crowning cylinders 119 and 121 to set the bending conditions, it is necessary to repeatedly perform trial bending and fine adjustment of the hydraulic pressure. There was a problem that the cost was high due to the complexity.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method and an apparatus for crowning in a press brake which does not require control of the hydraulic pressure of a crowning cylinder.

[0008]

According to a first aspect of the present invention, there is provided a crowning method for a press brake according to the present invention, wherein one of an upper table and a lower table has a movable side movable up and down on left and right side frames. Using a press brake with the fixed side, when performing bending of a plate material by cooperation of a punch and a die mounted on the upper table and the lower table, when the notch near the center in the left-right direction of the lower table By connecting the provided crowning cylinder and the adjusting cylinder provided between the left and right ends of the lower table and the left and right side frames via an oil passage, the load applied to the adjusting cylinder is reduced by the oil passage. Through the transmission to the crowning cylinder to adjust the amount of deflection of the lower table.

Therefore, the adjusting cylinder is simply provided without providing a hydraulic supply source such as a hydraulic pump or a hydraulic motor for supplying pressure oil to the crowning cylinder and the adjusting cylinder, and a control device for adjusting the hydraulic pressure of the crowning cylinder. A simple mechanism in which the adjusting cylinder and the crowning cylinder are connected by an oil passage is provided at a low cost and an appropriate crowning operation is automatically performed.

According to a second aspect of the present invention, there is provided a crowning device in a press brake according to the present invention, wherein one of an upper table and a lower table is provided on a left and right side frame as a movable side capable of moving up and down, and the other is provided as a fixed side. In a press brake for bending a plate material in cooperation with a punch and a die mounted on a table, a notch is provided near the center of the lower table in the left-right direction, and the amount of deflection of the lower table is adjusted in the notch. A crowning cylinder is provided, and an adjusting cylinder communicating with the crowning cylinder via an oil passage is provided between left and right ends of the lower table and left and right side frames.

Accordingly, the operation is the same as that of the first aspect, and a hydraulic supply source such as a hydraulic pump or a hydraulic motor for supplying hydraulic oil to the crowning cylinder and the adjusting cylinder, and a control for adjusting the hydraulic pressure of the crowning cylinder. Even if no device is provided, a simple mechanism in which an adjusting cylinder is simply provided and the adjusting cylinder and the crowning cylinder are connected by an oil passage, and the appropriate crowning operation is automatically performed at low cost.

According to a third aspect of the present invention, there is provided a crowning device for a press brake according to the present invention, wherein the crowning cylinder and the adjusting cylinder have substantially the same cylinder diameter. It is a feature.

Accordingly, since the diameters of the adjusting cylinders and the crowning cylinders are substantially the same, the same pressure as the bending pressure acts on the lower table as the crowning pressure, and proper crowning is performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a bending angle control method and apparatus according to the present invention will be described below with reference to the drawings, taking a hydraulic press brake as an example.

Referring to FIG. 1 and FIG. 2, a press brake 1 according to the present embodiment is intended for a descending hydraulic press brake. Press brake may be used.

The downward hydraulic press brake 1 is mounted on a lower surface of a movable table that can move up and down, that is, a ram, for example, an upper table 5 through a plurality of intermediate plates 3 in which punches P are arranged at equal intervals. Fixed.
The die D is mounted and fixed on the upper surface of, for example, the lower table 7 as a fixed table. Therefore, the upper table 5 is lowered, and the work W of the plate material is bent between the punch P and the die D in cooperation with the punch P and the die D.

In FIG. 1, the left and right side hydraulic cylinders 13 and 15 are provided above the left and right side frames 9 and 11 which constitute the main body frame. 15 piston rods 17
The upper table 5 is connected to the lower end of the table.

A lower table 7 is fixed to the lower part of the left and right side frames 9 and 11, and a notch 19 is provided at the center of the lower table 7, and a crowning device is provided in the notch 19. For example, two crowning cylinders 21 and 23 (hydraulic cylinders) are provided. By controlling the pressure of the pistons of the crowning cylinders 21 and 23, the amount of deflection at the center of the lower table 7 is adjusted.

Adjustment cylinders 25 and 27 are mounted on the lower portions of the left and right side frames 9 and 11, and the left and right ends of the lower table 7 are placed on the piston rods 29 of the adjustment cylinders 25 and 27. 7A and 7B are placed, and the lower table 7 is provided so as to be able to move up and down by being guided by a guide body 31 provided so as to be sandwiched from the front and rear below the left and right side frames 9 and 11.

The pressurizing chambers 25A and 27A of the adjusting cylinders 25 and 27 communicate with the pressurizing chambers 21A and 23A of the closer crowning cylinders 21 and 23 via, for example, a hydraulic pipe 33 as an oil path. Have been. That is,
In FIG. 1, the left adjusting cylinder 25 is connected to the left crowning cylinder 21, and the right adjusting cylinder 27 is connected to the right crowning cylinder 23 in FIG. 1. It is desirable that the diameters of the adjusting cylinders 25 and 27 and the crowning cylinders 21 and 23 be the same in that the same pressure as the bending pressure acts on the lower table 7 as the crowning pressure.

As described above, the above-mentioned crowning cylinders 21 and 23 and the adjusting cylinders 25 and 27 do not have a hydraulic supply source such as a hydraulic pump or a hydraulic motor for supplying hydraulic oil. And the adjusting cylinders 25, 27 are connected by a hydraulic line 33, and the hydraulic pressure is supplied through the hydraulic line 33 to the crowning cylinders 21, 27.
Between the cylinder 23 and the adjusting cylinders 25 and 27 (circulation)
It is a simple configuration to do.

Referring to FIG. 1, for example, a detection plate 35 is provided on the side surface of the right side frame 11 in FIG. 1, and a linear scale 37 is provided above the detection plate 35. A detector 39 for detecting the position of the linear scale 37 is provided integrally with the upper table 5. The detector 39 is electrically connected to a control device (not shown).

According to the above configuration, as shown in FIG. 4, work information such as plate thickness and material,
Product information such as target angle and bending length, punch P, die D
And the like are input by an input device (not shown) (step S1).

In order to bend the work W to the target bending angle θ, the distance between the punch P and the die D needs to be equal to the set distance S as shown in FIG. P for 90 ° as bending angle θ
The distance S between the die and the die D is calculated as a set value of the ram position by an arithmetic unit in the control device (step S2).

The linear scale 3 is detected by the detector 39 described above.
A command is given to lower the piston rods 17 of the left and right shaft hydraulic cylinders 13 and 15 so that the measured value obtained by detecting the position 7 becomes the calculated S value. This command lowers the upper table 5 (ram) to start bending (step S3).

At the time of this bending, as shown in FIG. 2, the pressing force of the left and right shaft hydraulic cylinders 13 and 15 is applied to the work held between the punch P and the die D via the upper table 5. Due to the reaction force of the workpiece W, the upper table 5 slightly deforms in a slightly upwardly curved direction due to the reaction force of the workpiece W. On the other hand, the lower table 7 tends to be slightly curved and deformed in a slightly downward direction by the reaction force of the work W.

However, the reaction force of the work W is not
From both ends of the lower table 7 to the adjusting cylinder 2
5, 27. The adjusting cylinders 25, 27
The oil in the adjusting cylinders 25 and 27 flows into the crowning cylinders 21 and 23 via the hydraulic line 33 due to the load applied to the cylinders 23 and 23, and excessive pressure is generated in the crowning cylinders 21 and 23, and the upper part of the lower table 7 is pressed upward. As a result, the lower table 7 slightly deforms in a slightly curved direction in a direction warping upward as shown in FIG.
That is, the distance between the punch P and the die D between the upper table 5 and the lower table 7 is uniformly adjusted, and a so-called crowning operation is automatically performed (step S4).

The position of the linear scale 37 is detected as a measured value by the detector 39, and it is judged by the comparison judging device of the control device whether the measured value matches a predetermined S value (steps S5 and S6).

If the measured value does not match the S value, the process returns to step S3, and the upper table 5 (ram) is further lowered. If the measured value matches the S value, the upper table 5
The lowering of the (ram) stops, and the work W is bent at a desired bending angle. At this time, even if the upper table 5 is curved and deformed upward, the longitudinal interval between the punch P and the die D is uniformly maintained by the crowning action as described above, so that the work W is formed at a uniform bending angle θ. It is bent.

Next, the upper table 5 is raised to the top dead center, and the bending is completed. When the upper table 5 rises,
Since the loads on the upper table 5 and the lower table 7 are released, the upper and lower tables 5 and 7 are no longer deformed in a curved manner, so that the crowning cylinders 21 and 23 are pressed downward by the return force of the lower table 7 to the original position. The oil in the crowning cylinders 21 and 23 is returned to the adjusting cylinders 25 and 27 via the hydraulic line 33 (step S).
7).

As described above, the crowning cylinder 2
1 and 23 and the adjusting cylinders 25 and 27, a hydraulic pump or a hydraulic motor for supplying hydraulic oil, or a control device for adjusting the hydraulic pressure of the crowning cylinders 21 and 23 is provided. A simple mechanism in which the cylinders 25 and 27 are provided and the crowning cylinders 21 and 23 and the adjustment cylinders 25 and 27 are connected by the hydraulic line 33 can be performed at low cost and with proper crowning action automatically.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes. In the present embodiment, a hydraulic press brake has been described as an example of a press brake, but an electric press brake and other press brakes may be used.

When the crowning device of the present invention is used for a lift press brake, the lower table becomes a movable table (ie, a ram) in the lift press brake. For example, an adjusting cylinder similar to that of the above-described embodiment is interposed between a piston rod of a hydraulic cylinder and a left and right end portions of a lower table as an elevating drive device that raises and lowers the portion, thereby achieving the above-described embodiment. A crowning effect similar to that of a down-type press brake of the form is performed.

[0034]

As will be understood from the above description of the embodiments of the invention, according to the first aspect of the present invention, the hydraulic pump and the hydraulic motor for supplying the hydraulic oil to the crowning cylinder and the adjusting cylinder are provided. And a control device that adjusts the hydraulic pressure of the crowning cylinder can be dispensed with, and a simple mechanism that simply provides the cylinder for adjustment and connects the crowning cylinder and the cylinder for adjustment with an oil passage is inexpensive. In addition, an appropriate crowning function can be automatically performed.

According to the second aspect of the present invention, the effect is the same as that of the first aspect, and a hydraulic supply source such as a hydraulic pump or a hydraulic motor for supplying pressurized oil to the crowning cylinder and the adjusting cylinder; A control device that adjusts the hydraulic pressure of the cylinder can be dispensed with, and a simple mechanism that simply provides an adjusting cylinder and connects the crowning cylinder and the adjusting cylinder with an oil path achieves inexpensive and appropriate crowning action. Can be done automatically.

According to the third aspect of the present invention, by making the diameters of the adjusting cylinders and the crowning cylinders substantially the same, the same pressure as the bending pressure can be applied to the lower table as the crowning pressure. It can be carried out.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a perspective view of a press brake provided with a crowning device.

FIG. 2 is a front view of FIG.

FIG. 3 shows an embodiment of the present invention, and shows a bending angle θ.
FIG. 4 is an explanatory diagram showing a set distance S value between a punch P and a die D with respect to FIG.

FIG. 4 shows an embodiment of the present invention and is a flowchart of bending work.

FIG. 5 is a front view of a press brake provided with a conventional crowning device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Hydraulic press brake 5 Upper table (ram, movable table) 7 Lower table (fixed table) 7A, 7B Both right and left ends 9 Side frame 11 Side frame 13 Left axis hydraulic cylinder 15 Right axis hydraulic cylinder 19 Notch 21, 23 Crowning Cylinder (crowning device) 21A, 23A Pressurizing chamber 25, 27 Cylinder for adjustment 25A, 27A Pressurizing chamber 33 Hydraulic pipeline (oil passage) 35 Detection plate 37 Linear scale 39 Detector

Claims (3)

[Claims] 1. A punch and a die mounted on the upper table and the lower table using a press brake having one of the upper table and the lower table movable on the left and right side frames and a movable side movable up and down, and the other fixed. When bending a plate material by cooperation, a crowning cylinder provided in a notch near the center in the left-right direction of the lower table, and an adjustment provided between left and right ends of the lower table and left and right side frames. A press brake, wherein a load applied to the adjusting cylinder is transmitted to the crowning cylinder through the oil passage to adjust the amount of deflection of the lower table by communicating with the cylinder for use via an oil passage. Crowning method. 2. One of the upper table and the lower table is provided on the left and right side frames as a movable side which can be moved up and down, and the other is provided as a fixed side, and a punch and a die mounted on the upper table and the lower table cooperate with each other. In a press brake for bending a plate material, a notch is provided near the center in the left-right direction of the lower table, and a crowning cylinder for adjusting the amount of deflection of the lower table is provided in the notch. A crowning device for press brakes, wherein an adjusting cylinder communicated with the lower table is provided between left and right ends of the lower table and left and right side frames. 3. The crowning device for a press brake according to claim 2, wherein said crowning cylinder and said adjusting cylinder have substantially the same cylinder diameter.