JP2001113317A - Press brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press brake capable of eliminating oil leakage, improving controllability and reducing a manufacturing man hour of the press brake. SOLUTION: In this press brake 1, bending is conducted by relatively up/down moving an upper table 5U or a lower table 5L with plural hydraulic cylinders 17L, 17R, in this case, the respective cylinders 17L, 17R are driven by respectively controlling the dual direction fluid pumps 31 arranged corresponding to the respective cylinders 17L, 17R and respective hydraulic apparatus 21L, 21R. The respective dual direction fluid pumps 31 and the respective hydraulic apparatus 21L, 21R for the plural hydraulic cylinders 17L, 17R to relatively move the upper table 5U or the lower table 5L up/down are mounted to a base plate 23 mounted to cylinder heads 18L, 18R of the respective hydraulic cylinders 17L, 17R, oil tanks 27 are arranged to the upper part of the hydraulic apparatus 21L, 21R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press brake provided with a hydraulic cylinder for moving an upper table or a lower table relatively up and down.

[0002]

2. Description of the Related Art Referring to FIGS. 5 and 6, a conventional hydraulic press brake 101 has side plates 103L and 103R erected on the left and right sides.
Upper table 105U on the upper front end face of 03L, 103R
And the side plates 103L, 103
A lower table 105L is fixedly provided on the lower front surface of the R.

[0003] Hydraulic cylinders 107L and 107R for vertically moving the above-mentioned upper table 105U are provided on the upper front surfaces of the side plates 103L and 103R. Pumps and oil tanks for controlling the hydraulic cylinders 107L and 107R are provided. , A hydraulic device 109 such as a control valve is collectively provided behind the center of the press brake 101, and is connected to each hydraulic cylinder 107 </ b> L, 107 </ b> R by a pipe 111. A punch P is provided at the lower end of the upper table 105U so as to be exchangeable, and a die D is provided at an upper end of the lower table 105L so as to be exchangeable.

Accordingly, the hydraulic cylinders 107L and 107R are driven under the control of the hydraulic device 109 to move the upper table 105U up and down, and the punch P and the die D cooperate to position the upper table 105U between the punch P and the die D. Bending is performed on the work.

[0005]

However, in such a conventional technique, each hydraulic cylinder 107L,
Since 107 </ b> R and the hydraulic device 109 are connected by the pipe 111, a pipe work is required above the press brake 101. That is, the hydraulic cylinder 107
Since the L and 107R and the hydraulic device 109 must be assembled separately and attached to a predetermined position and then piped, there is a problem that not only the number of work steps is increased but also danger is involved.

Further, since the long pipe 111 is provided, there is a problem that oil may leak in the pipe 111.

In addition, since the distance between the control valve provided in the hydraulic equipment 109 and the hydraulic cylinders 107L and 107R is long, the response is poor, the pressure loss is large, and heat is generated, resulting in poor controllability. is there.

[0008] Further, the upper table 105 during a sudden descent.
Hydraulic oil in the oil tank is sucked into the hydraulic cylinders 107L and 107R using the own weight of U. However, at the start of machining, the temperature of the hydraulic oil is low, so that the viscosity is high, and insufficient suction occurs to cause insufficient suction. Since the speed cannot be selected or cavitation occurs, there is a problem that the performance may be deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a press brake capable of solving the above-mentioned problems by paying attention to the above-mentioned problems of the conventional technology.

[0010]

According to a first aspect of the present invention, there is provided a press brake having a plurality of hydraulic cylinders for moving an upper table or a lower table relatively up and down. At
Each bidirectional fluid pump provided corresponding to each of the hydraulic cylinders is connected and provided via a hydraulic device, respectively, and the bidirectional fluid pump and each hydraulic device are configured to be individually controllable. Is what you do.

Therefore, in this press brake,
The bending operation is performed by moving the upper table or the lower table relatively up and down by a plurality of hydraulic cylinders. At this time, each hydraulic cylinder includes a bidirectional fluid pump and a hydraulic device provided corresponding to each hydraulic cylinder. Are individually controlled.

The press brake of the invention according to claim 2 is
In a press brake provided with a plurality of hydraulic cylinders for moving the upper table or the lower table relatively up and down, the bidirectional fluid pumps provided corresponding to the respective hydraulic cylinders are connected to each other via hydraulic devices and provided. A crowning cylinder is provided at the center of the lower table to improve the passage of the die provided at the upper end of the lower table, and a bidirectional fluid pump is connected to the crowning cylinder via a hydraulic device. Wherein each of the bidirectional fluid pumps and each of the hydraulic devices are configured to be individually controllable.

Therefore, in this press brake,
The bending operation is performed by moving the upper table or the lower table relatively up and down by a plurality of hydraulic cylinders. At this time, each hydraulic cylinder includes a bidirectional fluid pump and a hydraulic device provided corresponding to each hydraulic cylinder. Are individually controlled. The crowning cylinder provided on the lower table is also driven by individually controlling the bidirectional fluid pump and the hydraulic device provided corresponding to the crowning cylinder.

[0014] The press brake of the invention according to claim 3 is:
3. The press brake according to claim 1, wherein each hydraulic device that connects each bidirectional fluid pump and each hydraulic cylinder to a hydraulic cylinder for relatively moving the upper table or the lower table up and down is connected to each hydraulic device. Mounting on a base plate mounted above the cylinder, and providing an oil tank above this hydraulic device,
It is characterized by the following.

Therefore, each bidirectional fluid pump and each hydraulic device for a plurality of hydraulic cylinders for moving the upper table or the lower table relatively up and down are mounted on a base plate mounted above each hydraulic cylinder,
The oil tank is provided above the hydraulic device.

[0016]

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

FIGS. 1 and 2 show the entirety of a press brake 1 according to the present invention. The press brake 1 has side plates 3L and 3R erected on the left and right. An upper table 5U is vertically movable on upper front end surfaces of the side plates 3L and 3R, and a lower surface is provided on lower front surfaces of the side plates 3L and 3R. A table 5L is provided.

An intermediate plate 7 is provided at the lower end of the upper table 5U.
The punch P is exchangeably provided by a bolt 9 through the hole. A die D is provided at the upper end of the lower table 5L via a die base 11 so as to be exchangeable.

Both ends of the lower table 5L are side plates 3L, 3L.
R, but the central part can be lifted up slightly by a small amount.
Also, a crowning cylinder 13 is provided for correcting the downward displacement of the die D upward to improve the flow of the die D.

A linear scale 15 for measuring the height position of the upper table 5U is provided. The distance from the die D is determined from the height of the punch P to detect a bending angle and to ensure safety. It is carried out.

Hydraulic cylinders 17L and 17R are provided on the upper front surfaces of the left and right side plates 3L and 3R, respectively, and the piston rods 20L and 20R mounted on the pistons 19L and 19R of the hydraulic cylinders 17L and 17R are provided with the above-mentioned pistons. An upper table 5U is attached. Here, the hydraulic cylinders 17 provided on the left and right side plates 3L, 3R are provided.
L, 17R and the hydraulic devices 21L, 21R for controlling the hydraulic cylinders 17L, 17R are provided independently of each other, so that the right side plate 3
The hydraulic cylinder 17R and the hydraulic equipment 21R provided in R will be described.

Cylinder head 22 of hydraulic cylinder 17R
Base plate 2 is provided on the upper side of R and on the upper end surface of side plate 3R.
3 is attached, and a hydraulic device 21 </ b> R is provided on an upper surface of the base plate 23. For example, a prefill valve 25 is provided above the hydraulic cylinder 17 </ b> R on the upper surface of the base plate 23, and an oil tank 27 is provided above the prefill valve 25.

A manifold 29 and the like are provided on the upper surface of the base plate 23 behind the prefill valve 25 (right direction in FIG. 2), and a bidirectional piston pump, which is a bidirectional fluid pump, is provided on the upper rear side of the side plate 3R. An AC servomotor 33 is provided as a servomotor for driving the bidirectional piston pump 31 and the bidirectional piston pump 31, for example.

Next, referring to FIG.
The hydraulic circuit for R will be described. Here, the right hydraulic cylinder 17R and the hydraulic circuit will be described, but the same hydraulic cylinder 17RL is also used on the left.
The hydraulic circuit is provided as described above.

The upper cylinder chamber 35U of the hydraulic cylinder 17R for vertically moving the upper table 5U, which is a ram, is connected by a pipe 37 to the prefill valve 25 of the hydraulic equipment 21R provided above the hydraulic cylinder 17R. Is connected to an oil tank 27 provided above the hydraulic cylinder 17R.

The upper cylinder chamber 35U is provided with a pipe 4
1 bidirectional piston pump 31 capable of bidirectional rotation
Are connected to one side. A pipe 43 is connected to the pipe 41 on the way, and is connected to the oil tank 27 via a check valve 45 and a suction filter 47. The bidirectional piston pump 31 is driven to rotate by an AC servomotor 33.

On the other hand, a pipe 49 is connected to the lower cylinder chamber 35L of the hydraulic cylinder 17R, and a counter balance valve 51 and a sequence switching valve 53 which is an electromagnetic poppet valve are provided in parallel. The counter balance valve 51 and the sequence switching valve 53 are connected to the other side of the bidirectional piston pump 31 by a pipe 55. The pipe 55 is connected to the oil tank 27 by a pipe 61 via a check valve 57 and a suction filter 59.

In the middle of the pipe 49, a throttle valve 63 and a high-pressure priority type shuttle valve 65 are provided. A pipe 67 is connected to the discharge side of the high-pressure priority shuttle valve 65, and the pipe 67 is provided with a relief valve 69 and a pipe 71.

With the above structure, the upper cylinder chamber 35U and the lower cylinder chamber 35L are filled with hydraulic oil, the bidirectional piston pump 31 is stopped, and the piston 19R is at the top dead center. When the upper table 5U is rapidly lowered by 17R, the sequence switching valve 53 is switched to connect the pipes 49 and 55, and the bidirectional piston pump 31 is rotated by the AC servomotor 33.

In the case of performing the bending process by further descending,
With the sequence switching valve 53 in the state shown in FIG. 3, the hydraulic oil from the lower cylinder chamber 35 </ b> L is transferred from the pipe 41 to the hydraulic cylinder 17 </ b> R by the bidirectional piston pump 31 through the pipe 49, the counterbalance valve 51 and the pipe 55. It is injected into the cylinder chamber 35U. Thereby, the piston 19R descends, and the upper table 5U descends to perform bending.

Since the cross-sectional area of the lower surface of the piston 19R is smaller than that of the upper surface, the amount of the hydraulic oil discharged from the lower cylinder chamber 35L is smaller than the amount of hydraulic oil injected into the upper cylinder chamber 35U. Since the amount of hydraulic oil returning to the pump 31 is small, hydraulic oil is replenished from the oil tank 27 via the check valve 57.

On the other hand, when the upper table 5U is raised by the hydraulic cylinder 17R, the switching valve 53 is switched to the state shown in FIG. 3 and the AC servo motor 33 is rotated in the opposite direction to the above-described case. The bidirectional piston pump 31 is reversed, and the hydraulic oil from the upper cylinder chamber 35U with the piston 19R lowered is injected into the lower cylinder chamber 35L through the pipe 41 and the bidirectional piston pump 31. As a result, the piston 19R rises and the upper table 5U rises.

When the pressure of the hydraulic oil injected into the lower cylinder chamber 35L becomes higher than a predetermined value, the prefill valve 25 is opened by the pilot signal 73, and the upper cylinder chamber 35L is opened.
U is discharged to the oil tank 27 through the prefill valve 25.

From the above results, the bidirectional piston pump 3
1, the piston 19R of the hydraulic cylinder 17R is moved up and down, so that there is no need to use a switching valve and a flow control valve as in the prior art, and the AC servomotor 33 and the bidirectional piston pump are used when the piston 19R is stopped. Since there is no need to rotate 31, it is possible to prevent an increase in oil temperature. With this, oil tank 2
7 can be greatly reduced (approximately 1/4 to 1/5 of the prior art), and the size and cost of the device can be reduced.

Further, the oil tank 27, the bidirectional piston pump 31, and the AC
Since the hydraulic equipment 21R such as the servomotor 33 is provided, the piping can be shortened, and the piping work can be facilitated. In addition, oil leakage can be reduced,
The controllability can be improved by reducing the pressure loss.

Further, since the distance between the hydraulic cylinder 17R and the oil tank 27 is short, the hydraulic oil is easily sucked from the oil tank 27 when the upper table 5U is lowered. Can be.

Further, since the bidirectional piston pump 31 is rotationally driven by the AC servomotor 33 capable of high-precision control, high-precision control of hydraulic pressure is possible, and bending accuracy can be improved.

FIG. 4 shows a hydraulic circuit of the crowning cylinder 13. In this hydraulic circuit, a pipe 77 is connected to a lower cylinder chamber 75 of the crowning cylinder 13, and the pipe 77 is connected to an AC servomotor 79.
Is connected to the oil tank 27 via a bidirectional piston pump 81 driven to rotate. Further, the pipe 77 is connected to the oil tank 27 via a relief valve 83.

With the configuration shown in FIG. 4, the bidirectional piston pump 81 is rotated by the AC servomotor 79 to supply hydraulic oil to the lower cylinder chamber 75 of the crowning cylinder 13 to raise the piston 85, thereby lowering the lower table 5L. , And correct the street of die D. When lowering the piston 85, the bidirectional piston pump 81 is rotated in the opposite direction by the AC servomotor 79 to discharge the hydraulic oil in the lower cylinder chamber 75 to the oil tank 27.

From the above results, the bidirectional piston pump 8
1 is used to move the piston 85 of the crowning cylinder 13 up and down, so there is no need to use a switching valve as in the prior art.
Since it is not necessary to rotate the C servo motor 79 and the bidirectional piston pump 81, it is possible to prevent an increase in oil temperature. Along with this, the capacity of the oil tank 27 can be significantly reduced (about 1/4 to 1/5 of the conventional one), and the apparatus can be made compact and the cost can be reduced.

Further, since the bidirectional piston pump 81 is driven to rotate by the AC servomotor 79 capable of high-precision control, high-precision control of the hydraulic pressure is possible, and the bending accuracy is corrected by correcting the shape of the die D. Can be improved.

3 and 4, the relief valve 6
Reference numerals 9, 83 serve as safety valves when the pressure becomes excessive.

It should be noted that the present invention is not limited to the above-described embodiment of the present invention, but by making appropriate changes,
It can be implemented in other aspects.

[0044]

As described above, in the press brake according to the first aspect of the present invention, the bending operation is performed by moving the upper table or the lower table relatively up and down by a plurality of hydraulic cylinders. Since the hydraulic cylinders are driven by individually controlling the bidirectional fluid pump and each hydraulic device provided corresponding to each hydraulic cylinder, there is no need to use a conventional switching valve,
Further, when the hydraulic cylinder is stopped, it is not necessary to rotate the bidirectional piston pump, so that an increase in oil temperature can be prevented. Accordingly, the capacity of the oil tank can be significantly reduced, and the device can be made more compact.

In the press brake according to the second aspect of the invention, in this press brake, bending is performed by moving the upper table or the lower table relatively up and down by a plurality of hydraulic cylinders. It is driven by individually controlling the bidirectional fluid pump and each hydraulic device provided corresponding to each hydraulic cylinder. In addition, the crowning cylinder provided on the lower table is also driven by controlling the bidirectional fluid pump and the hydraulic device provided corresponding to the crowning cylinder, so that it is necessary to use a conventional switching valve. In addition, when the hydraulic cylinder is stopped, it is not necessary to rotate the bidirectional piston pump, so that an increase in oil temperature can be prevented. Along with this,
The capacity of the oil tank can be greatly reduced, and the device can be made more compact.

In the press brake according to the third aspect of the present invention, each bidirectional pump and each hydraulic device for a plurality of hydraulic cylinders for moving the upper table or the lower table relatively up and down are mounted on a base plate mounted above each hydraulic cylinder. Since it is attached and the oil tank is provided above the hydraulic device, the piping can be shortened. Thereby, piping work can be facilitated, oil leakage can be reduced, pressure loss can be reduced, and controllability can be improved. Further, since the distance between the hydraulic cylinder and the oil tank is short, the hydraulic oil is easily sucked from the oil tank when the upper table or the lower table is lowered, so that the hydraulic oil can be quickly lowered without causing insufficient suction of the hydraulic oil.

[Brief description of the drawings]

FIG. 1 is a front view of a press brake according to the present invention.

FIG. 2 is a side view as viewed from a direction II in FIG.

FIG. 3 is a hydraulic circuit of a hydraulic cylinder of a press brake according to the present invention.

FIG. 4 is a hydraulic circuit of a crowning cylinder in a press brake according to the present invention.

FIG. 5 is a front view showing a conventional press brake.

FIG. 6 is a plan view seen from a VI direction in FIG. 5;

[Explanation of symbols]

Reference Signs List 1 press brake 5U upper table 5L lower table 17L, 17R hydraulic cylinder 13 crowning cylinder 18L, 18R cylinder head 21L, 21R hydraulic equipment 23 base plate 27 oil tank 31, 81 bidirectional piston pump (bidirectional fluid pump)

Claims (3)

[Claims] 1. A press brake provided with a plurality of hydraulic cylinders for moving the upper table or the lower table relatively up and down, wherein each bi-directional fluid pump provided corresponding to each of the hydraulic cylinders is connected via a hydraulic device. Wherein the bidirectional fluid pumps and the hydraulic devices are individually controllable. 2. A press brake having a plurality of hydraulic cylinders for moving the upper table or the lower table relatively up and down, wherein each bi-directional fluid pump provided corresponding to each of the hydraulic cylinders is connected via a hydraulic device. A crowning cylinder is provided at the center of the lower table in order to improve the passage of the die provided at the upper end of the lower table. A press brake, wherein each of the bidirectional fluid pumps and each hydraulic device are individually controllable. 3. The press brake according to claim 1, wherein each hydraulic device is connected to each bidirectional fluid pump and each hydraulic cylinder for a hydraulic cylinder for relatively moving the upper table or the lower table up and down. To
A press brake, characterized in that it is mounted on a base plate mounted above each of the hydraulic cylinders, and an oil tank is provided above the hydraulic equipment.