JPH05305348A - Press brake - Google Patents

Abstract

PURPOSE:To precisely bend without deviating the position of the metal plate supported with the lower die by providing the control motor to adjust the opening degree of the 1st and the 2nd mechanical control valves. CONSTITUTION:A hydraulic oil is carried to a main cylinder room of a hydraulic cylinder 13 through a circuit 25 without carrying the hydraulic oil to the 3rd and the 4th circuits 31, 33 by controlling tone drive of a servo motor 71, lowering a nut member 77 and becoming the controlling valves 35, 37 to the all closed state. The lower die 11 supporting the metal plate W is elevated with the rapid velocity as one body with a lower frame 17. When the arrival to the prescribed height is detected with a height detector 79, the nut member 77 is gradually lowered by further controlling the drive of the servo motor 71. The elevating velocity of the lower frame 7 becomes gradually late, when it arrives to the height position for beginning working, the metal plate W bending is began. Therefore, the lower frame is not largely vibrated due to the change of the elevating velocity and the pressurizing force of the lower frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press brake capable of bending a plate material supported by a lower die by moving the lower die up and down.

[0002]

2. Description of the Related Art In general, a press brake comprises an upper frame having an upper die and a lower frame having a lower die, which are vertically opposed to each other. There are two types of modes for raising and lowering the lower frame. In the latter press brake which raises and lowers the lower frame, a main hydraulic cylinder and a sub hydraulic cylinder for raising and lowering the lower frame are provided in order to bend the plate material supported by the lower mold. The main hydraulic cylinder and the pump are connected via the first circuit, and the sub hydraulic cylinder and the pump are connected via the second circuit. A directional control valve capable of switching the connection state between the sub hydraulic cylinder and the pump is arranged in the middle of the second circuit.

With the above construction, after the plate material is supported on the lower die, the solenoid of the directional control valve is operated to disconnect the connection between the sub hydraulic cylinder and the pump.
The pump is operated to supply the pressure oil into the main hydraulic cylinder via the first circuit. As a result, the pressure oil is not positively supplied into the sub hydraulic cylinder, but is positively supplied into the main hydraulic cylinder, and the lower frame and the lower die are moved up at a relatively high speed.

After the plate material approaches the upper die due to the rise of the lower frame, the solenoid of the directional control valve is operated to switch the sub hydraulic cylinder and the pump to the connected state, so that not only the main hydraulic cylinder but also the sub hydraulic cylinder. Pressure oil is positively supplied also inside. As a result, the lower frame rises at a relatively slow speed, and the force for pressing the lower frame also increases, so that the plate material can be bent under sufficient pressure.

[0005]

However, in the conventional press brake as described above, the ascending speed of the lower frame is switched from a relatively high speed to a relatively slow speed by operating the solenoid of the directional control valve. Since the force for pressing the lower frame is also switched from a small force to a large force, the lower frame tends to vibrate due to fluctuations in the rising speed of the lower frame and fluctuations in the force pressing the lower frame when the directional control valve is switched. .. Therefore, there is a problem that the plate material supported by the lower mold is displaced when the direction control valve is switched, and the plate material cannot be precisely bent.

Therefore, an object of the present invention is to provide a press brake which can solve the above problems.

[0007]

In order to solve the above-mentioned conventional problems, in the present invention, an upper frame having an upper die and a lower frame having a lower side are provided so as to face each other vertically. In order to perform bending work on the plate material supported by the lower die, in a press brake in which a lower frame can be raised and lowered, a main hydraulic cylinder and a sub hydraulic cylinder for raising and lowering the lower frame are provided. The hydraulic cylinder and the pump are connected via a first circuit, the sub-hydraulic cylinder and the tank are connected via a second circuit, and a check valve is arranged in the middle of the second circuit. The third circuit is connected between the circuit and the portion of the second circuit that is closer to the cylinder than the check valve, and
A fourth circuit is connected between a portion of the third circuit and the second circuit which is closer to the tank than the check valve, and the third circuit and the fourth circuit are connected.
The first mechanical control valve is arranged at the connecting portion of the circuit, the second mechanical control valve is arranged in the middle of the fourth circuit, and the second mechanical control valve is arranged when the first mechanical control valve is fully closed. Is fully closed, and the first mechanical control valve is configured so that the opening degree can be adjusted within a predetermined opening degree range even when the second mechanical control valve is in the fully closed state. (2) A control motor for adjusting the opening degree of the mechanical control valve is provided.

[0008]

In the above structure, after the plate material is supported by the lower mold, the opening degree of the first and second mechanical control valves is adjusted,
The first and second mechanical control valves are fully closed (openness 0). As a result, the pressure oil is supplied into the main hydraulic cylinder via the first circuit by the operation of the pump, and the lower die supporting the plate material can rise integrally with the lower frame at a relatively high speed. At this time, since the pressure is reduced in the sub hydraulic cylinder, pressure oil is sucked into the sub hydraulic cylinder via the tank, the second circuit, and the check valve.

When the lower mold rises at a relatively high speed and approaches the upper mold, the control motor is appropriately operated to open the first mechanical control valve while the second mechanical control valve is fully closed. Is gradually increased from the fully closed state. As a result, the pressure oil supplied by the pump is not only positively sent into the main hydraulic cylinder via the first circuit, but also the sub hydraulic pressure is supplied via the first circuit, the third circuit, and the first mechanical control valve. It is gradually fed into the cylinder. Therefore, the rising speed of the lower die gradually decreases, and the force for pressing the lower frame from the lower direction gradually increases, so that the plate material can be bent under sufficient pressure.

After performing a desired bending process on the plate material, the control motor is appropriately controlled to increase the opening degree of the first and second mechanical control valves. As a result, the pressure oil in the main hydraulic cylinder is discharged to the tank via the first circuit, the third circuit, the fourth circuit, and the second circuit, and the pressure oil in the sub hydraulic cylinder is discharged in the second circuit, the third circuit. , Is discharged to the tank via the fourth circuit. As a result, the lower frame descends.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, a press brake 1 is provided with a pair of left and right standing side frames 3 (front and back directions toward the paper surface in FIG. 1 and front and back directions toward the paper surface in FIG. 2). On the front side (right side in FIG. 1, left side in FIG. 2) of the pair of side frames 3, there are provided an upper frame 5, a lower frame 7 and the like which are vertically opposed.

The upper frame 5 is fixed to the side frame 3, and an upper die 9 is provided below the upper frame 5. The lower frame 7 is provided on the side frame 3 so as to be able to move up and down, and a lower mold 11 is provided above the lower frame 7.
Is provided. Hydraulic cylinders 13 are provided at appropriate lower positions of the left and right side frames 3 to raise and lower the lower frame 7. The hydraulic cylinder 1
The cylinder 3 includes a cylinder 15, a U-shaped piston 17 that is vertically movable in the cylinder 15, and main and sub-cylinder chambers 19 and 21 provided below the piston 17 in the cylinder 15. Here, the piston 17 is connected to the lower frame 7, and the sub-cylinder chamber 21 is provided around the main cylinder chamber 19.

A hydraulic circuit device 23 for operating the hydraulic cylinder 13 will be described.

The main hydraulic chamber 19 of the hydraulic cylinder 13 and the pump P are connected via a first circuit 25, and the sub-cylinder chamber 21 of the hydraulic cylinder 13 and the tank T are connected to the second circuit 2 of the hydraulic circuit 13.
It is connected via 7. In the middle of the first circuit 25, a directional control valve 28 that can switch between connection and disconnection with the pump P is provided. Further, a check valve 29 is provided in the middle of the second circuit 27, and the first circuit 25 and the second circuit 27 are provided.
A third circuit 31 is connected between the check valve 29 and the cylinder side. Furthermore, the third circuit 31
A fourth circuit 33 is connected between the second circuit 27 and a portion of the second circuit 27 closer to the tank than the check valve 29.

A first mechanical control valve 35 is provided at the connecting portion between the first circuit 25 and the fourth circuit 33, and an appropriate number (two in this embodiment, two in this embodiment) is provided in the middle of the fourth circuit 33. 7
The second mechanical control valve 37 (see the reference) is provided. The first and second mechanical control valves 35, 37 mainly have the function of controlling the flow rate of the pressure oil, and the second mechanical control valve 35 is in the fully closed state (openness 0). The control valve 37 is also in the fully closed state, and the opening degree of the first mechanical control valve 37 is adjustable within a predetermined opening degree range even when the second mechanical control valve 37 is in the fully closed state.

Here, a part of the first circuit 25, a part of the second circuit 27, a third circuit 31, and a fourth circuit 33 are provided in a fixing member 39 provided at an appropriate position below the hydraulic cylinder 13, Similarly, the check valve 29, the first mechanical control valve 35, and the second mechanical control valve 37 are also provided on the fixed member 39. A pressure gauge 41 for measuring the pressure in the first circuit 25 is provided at a position close to the fixing member 39.

A spool actuating device 43 is provided for vertically adjusting the spools 35S, 37S of the mechanical control valves 35, 37 in order to adjust the opening degrees of the first mechanical control valve 35 and the second mechanical control valve 37. ..

Referring to FIGS. 1, 7, 8 and 9, the spool actuating device 43 will be described in detail. The rear side of the fixing member 39 (the left side in FIGS. 1, 7, and 8, FIG. 9). The bracket 45 provided on the back side (toward the paper surface)
A pair of lever supporting members 47 are provided on the lever supporting member 47, and a lever 49 extending in the front-rear direction is provided on the lever supporting member 47 so as to be vertically swingable via a pin 51. In order to regulate the downward swing range of the lever 49 on the front end side, a stopper bolt 53 is provided at an appropriate position on the front end side of the lever 49, and the head of the stopper bolt 53 is the upper surface of the fixing member 39. Can abut.

Plural sets (three sets in this embodiment) of bearings 55, 57 and 59 as spool supporting members are provided at appropriate positions on the front end side of the lever 49, and the outer rings of the bearings 55, 57 and 59 are As shown in FIG. 9, it is fixed to the lever 49 via appropriate means. Bearing 5 above
The hexagonal spool 35S of each first mechanical control valve 35 is supported on pins 5 and 57 via a pin 61, and the hexagonal spool 37S of the second mechanical control valve 37 is pinned on the bearing 59. It is supported via 63.
In addition, the spools 35S, 37 are provided at appropriate positions of the lever 49.
A notch portion 65 through which each S penetrates is provided.

In order to swing the lever 49 in the vertical direction, a swing member 67 is provided at an appropriate position in the side frame 3 so as to swing the pin 68 in the vertical direction, and one end of the swing member 67 is provided. Is connected to the rear end of the lever 49 via a connecting member 69 extending in the vertical direction. In order to swing the swinging member 67 in the vertical direction, a control motor such as a servo motor 71 is mounted at an appropriate position on the rear side of the lower frame 7 through a mounting member 73, and is linked to the servo motor 71. The ball screw 75 is attached to the swinging member 6
A nut member 77 connected to the other end of the screw 7 is provided by screwing.

In order to detect the height position of the lower frame 7, a height position detecting device 79 is provided at an appropriate position. More specifically, a rack member 81 extending in the vertical direction is provided at an appropriate position on the side frame 7, and a pinion 83 meshing with the rack member 81 is rotatably provided at an appropriate position on the lower frame 7. And pinion 8
3 includes an encoder 85 for detecting the number of rotations of the pinion 71, and the servomotor 71 is drive-controlled in accordance with the detected value of the encoder 85.

The operation of this embodiment based on the above-mentioned structure will be described with reference to FIGS.

When the lower frame 17 is located at the lowest position, the first and second mechanical control valves 35, 37.
Is fully open. Therefore, even if the pump P is operated, the pressure oil is not positively supplied to the main and sub cylinder chambers 19 and 21, and the first circuit 25, the third circuit 31, the first mechanical control valve 35, the fourth circuit 33, the second mechanical control valve 37, and the second circuit 27 are discharged to the tank T (see FIG. 2). At this time, it is desirable to switch the directional control valve 28 as appropriate to disconnect the connection between the main cylinder chamber 19 and the pump P.

After the lower frame 17 is positioned at the lowermost height position, the plate material W is supported by the lower mold 11. Then, the servo motor 71 is appropriately driven and controlled to lower the nut member 77 with respect to the swing member 67, whereby the front end side (left end side in FIGS. 2 to 6) of the lever 49 swings downward. The spools 35S and 37S of the first and second mechanical control valves 35 and 37 also move downward. As a result, the first and second mechanical control valves 35 and 37 are in a fully closed state (openness 0), and the pressure oil supplied by the pump P is not sent to the third and fourth circuits 31 and 33, It is sent to the main cylinder chamber 19 of the hydraulic cylinder 13 via the first circuit 25. Therefore, the lower mold 11 supporting the plate material W moves up integrally with the lower frame 17 at a relatively high speed (see FIG. 3). At this time, by appropriately controlling the drive of the servo motor 71, the height position of the nut member 77 with respect to the swinging member 67 can be kept substantially constant, and the first and second mechanical control valves 3 can be controlled.
It is also possible to keep the openness of 5, 37 constant.

On the other hand, when the lower mold 11 rises integrally with the lower frame 7 at a relatively high speed, the pressure oil is pumped by the pump P.
Is not positively sent to the sub-cylinder chamber 21 by the operation of the sub-cylinder chamber 21, but the pressure in the sub-cylinder chamber 21 is reduced. It is sucked into the chamber 21 (see FIG. 3).

The height detecting device 79 indicates that the lower frame 7 is lifted and the lower mold 11 is located at a predetermined height position close to the upper mold 9 (a height position close to the processing start height position).
When it is detected by, the servo motor 71 is further driven and controlled, and the nut member 77 is gradually lowered with respect to the swing member 67. As a result, the front end side of the lever 49 gradually swings upward, and the opening degree of the first mechanical control valve 35 gradually increases while the second mechanical control valve 37 is fully closed. As a result, the pressure oil supplied by the pump P is not only positively sent into the main cylinder chamber 19 via the first circuit 25, but also the first circuit 2
5, is gradually fed into the sub hydraulic cylinder chamber 21 via the third circuit 31 and the first mechanical control valve 35 (see FIG. 4). Therefore, the rising speed of the lower frame 7 gradually decreases, and when the processing start height position is reached, the bending of the plate material W is started. Further, the force of pressing the lower frame 7 from the lower direction gradually increases, and the plate material W can be bent under a sufficient pressure.

When the height detecting device 79 detects that the lower frame 7 is located at the processing end height position by raising the lower frame 7 at a relatively slow speed, the drive of the servo motor 71 is stopped. by this,
The opening of the second mechanical control valve 37 balances the weight of the lower frame 7, the lower mold 11 and the force of the pressure oil to stop the lifting operation of the lower frame 7 and position the lower frame 7 at the processing end height position. (See FIG. 5).

When the lower frame 7 approaches the machining end height position, the driving of the servo motor 71 can be stopped to stop the lower frame 7 at the machining end height position.

After the lower frame 7 is positioned at the processing end height position and the desired bending process is performed on the plate W, the servo motor 71 is drive-controlled to move the nut member 77 to the swing member 67. Lever 4 by raising
The front end side of 9 swings upward, and the opening degree of the first and second mechanical control valves 35, 37 can be increased. Therefore, the pressure oil in the main cylinder chamber 19 is
5, the third circuit 31, the fourth circuit 33, and the second circuit 27 are carried out to the tank T, and the pressure oil in the sub-cylinder chamber 21 is the second circuit 27, the third circuit 31, and the fourth circuit 33. It is carried out to the tank T via (see FIG. 6). Therefore, the lower frame 7 can be lowered and can be positioned at the most lowered height position.

According to this embodiment as described above, when the plate W is bent, the ascending speed of the lower frame 7 gradually changes from a relatively high speed to a relatively slow speed. The force that pressurizes the lower frame 7 also gradually changes from a relatively small force to a relatively large force. Therefore, the lower frame 7 does not vibrate significantly due to the rising speed of the lower frame 7 and the fluctuation of the force that presses the lower frame 7, and the position of the plate material W supported by the lower mold 11 is not displaced. The plate material W can be precisely bent.

Next, a second embodiment will be described with reference to FIGS. Since only the configuration of the spool operating device 87 is different from the invention according to the second embodiment, the configuration of the spool operating device 87 will be described.

A guide member 89 extending vertically is provided on the side frame 3, and a motor support member 93 having a servo motor 91 is provided on the guide member 89 so as to be vertically movable. A lever 95 is integrally provided on the front side of the motor support member 89 (on the right side in FIG. 10 and on the back side in FIG. 11), and the lever 95 is provided on the first and second mechanical control valves 35, 27. The spool 35
It is connected to S and 37S.

A pole screw 97 extending vertically is rotatably provided on the motor support member 89 via a bearing 99. The ball screw 97 is used for the servomotor 9
Linked to 1. A nut member 101, which is supported by a guide member 89 so as to be able to move up and down, is screwed onto the ball screw 97, and the nut member 101 is attached to the lower frame 7.
It is supported by a support bracket 103 provided on the rear side.

Also in the second embodiment as described above, the first
The same operation and effect as those of the embodiment are exhibited.

The present invention is not limited to the description of the above embodiments, but instead of providing the hydraulic cylinder 13 having a structure in which the main hydraulic cylinder and the sub hydraulic cylinder are combined, the hydraulic cylinder 13 is replaced by the main hydraulic cylinder. It can be implemented in various other modes by making appropriate changes such as division into sub hydraulic cylinders.

[0037]

As will be understood from the above description of the embodiments, according to the present invention, when the plate material is bent, the lower frame is moved up from a relatively high speed to a relatively high speed. As the speed gradually decreases, the force for pressing the lower frame gradually changes from a relatively small force to a relatively large force. Therefore, the lower frame does not vibrate significantly due to the rising speed of the lower frame and the fluctuation of the force that presses the lower frame, and the position of the plate material supported by the lower mold is not displaced, so that the plate material is accurately bent. It can be processed.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a press brake according to a first embodiment.

FIG. 2 is an explanatory view of the operation of the first embodiment.

FIG. 3 is an explanatory view of the operation of the first embodiment.

FIG. 4 is an explanatory view of the operation of the first embodiment.

FIG. 5 is an explanatory view of the operation of the first embodiment.

FIG. 6 is an explanatory view of the operation of the first embodiment.

FIG. 7 is a view showing a main part of a spool operating device.

FIG. 8 is a plan view of FIG.

9 is a right side view of FIG. 7.

FIG. 10 is a diagram showing a main part of a press brake according to a second embodiment.

11 is a view taken along line XI-XI in FIG.

[Explanation of symbols]

 1 Press Brake 5 Upper Frame 7 Lower Frame 9 Upper Mold 11 Lower Mold 13 Hydraulic Cylinder 19 Main Cylinder Chamber 21 Sub-Cylinder Chamber 25 First Circuit 27 Second Circuit 29 Check Valve T Tank P Pump 31 Third Circuit 33 Fourth Circuit 35 1st mechanical control valve 37 2nd mechanical control valve 71 Control motor

Claims (1)

[Claims] 1. An upper frame having an upper die and a lower frame having a lower side are vertically opposed to each other, and a lower frame is provided to bend a plate material supported by the lower die. In the press brake that can be raised and lowered,
A main hydraulic cylinder and a sub hydraulic cylinder for raising and lowering the lower frame are provided, the main hydraulic cylinder and the pump are connected through a first circuit, and the sub hydraulic cylinder and the tank are connected through a second circuit. A check valve is disposed in the middle of the second circuit, and the third circuit is connected between the first circuit and the second circuit between the check valve and the cylinder side. Between the check valve and the tank side of the second circuit.
A circuit, and a first part is provided at a connecting portion between the third circuit and the fourth circuit.
A mechanical control valve is provided, a second mechanical control valve is provided in the middle of the fourth circuit, and when the first mechanical control valve is fully closed, the second mechanical control valve is also fully closed. , The first mechanical control valve is configured to be adjustable in opening degree within a predetermined opening degree range even when the second mechanical control valve is fully closed, and the opening degrees of the first mechanical control valve and the second mechanical control valve are A press brake, characterized in that it is provided with a control motor for adjusting.