JPH0237247B2 - PURESUBUREEKI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press brake, and more particularly to a press brake configured to operate up and down while keeping a ram horizontal at all times.

Conventionally, in order to maintain the horizontal level of a ram that is raised and lowered by the operation of hydraulic cylinders installed on both sides of a fixed table fixed to the left and right side plates,
Guide rollers are installed near the left and right sides of the ram, and a steel belt is hung diagonally around the guide rollers.
There is a configuration in which one end of the steel belt extending in the vertical direction is connected to a spool of a switching valve, and the other end is connected to a fixed part.

In the above configuration, when the ram is tilted in an appropriate direction, the steel belt is pulled, and when the ram is tilted in the opposite direction, the steel belt is loosened, and the spool of the switching valve is switched. By switching the switching valve, the flow rate of pressure oil to one hydraulic cylinder is controlled, and one side of the ram is raised or lowered rapidly or slowly, and the inclination of the ram is corrected to ensure that it is always level. This is the configuration to maintain.

The above-mentioned conventional structure is susceptible to the expansion and contraction of the steel belt due to temperature changes, and adjustment in response to temperature changes is troublesome.

In order to solve the conventional problems as mentioned above,
For example, a rack is provided on both the left and right sides of the back of a ram that can be raised and lowered, a rigid bar is rotatably attached to the left and right side plates, and a pinion gear that engages with the rack is attached to the outer periphery of the rack. As a possible configuration, it is also possible to synchronize the lifting and lowering operations on both the left and right sides of the ram.

However, in order to synchronize the lifting and lowering operations on both the left and right sides of the ram, it is necessary to have a highly rigid bar that hardly twists, and a highly rigid bar naturally requires a large diameter bar. Since the rack and pinion gear are also large, the press brake as a whole becomes large and heavy, which inconveniences the cost.

The present invention has been made in view of the above problems, and preferred embodiments will be described in detail below based on the drawings.

The press brake, generally indicated by the reference numeral 1 in FIGS. 1 and 2, has a fixed table 3 fixed to a lower machine base 5, and hydraulic cylinders 11 and 13 on the upper parts of left and right side plates 7 and 9. We are prepared.

Its piston rods 15 and 17 cause the ram 19
is driven and moved up and down relative to the fixed table 3, and a plate material is held and pressed between a movable mold (not shown) attached to the lower surface of the ram 19 and a fixed mold (not shown) attached to the upper surface of the fixed table 3. The structure is such that the bending process is performed using the same method.

In this embodiment, a tubular torsion bar 21 is rotatably attached to the left and right side plates 7 and 9 in parallel with the fixed table 3, and its tenon members 23, 25
(for example, the right tenon member 23), one end of a bar member 27 located at the axis of the torsion bar 21 is fixed by appropriate means such as welding, and the end of this bar member 27 is fixed to the other tenon member 25 (for example, the right tenon member 23). The one on the left in FIG. 1) is rotatably provided via a metal bearing 29 or the like. That is, the rod member 27 is provided so as to rotate together with one end side of the torsion bar 21.

Rotating levers 31 and 33 are fixed near the left and right ends of the torsion bar 21 by appropriate means, and the ram 1
Near both left and right sides of the rear surface of 9, the rotating lever 31,
Hinge pin bracket 3 is located at the position corresponding to 33.
5 are fixed to each other, and each rotating lever 3
1 and 33 and each hinge pin bracket 35 are connected via a link 37, a lower shaft pin 39, and an upper shaft pin 41, and are configured so that the vertical movement of the ram 19 directly manifests as rotation of the torsion bar 21. There is. In other words, the torsion bar 21 is configured so that the vicinity of both ends of the torsion bar 21 rotates in conjunction with the lifting and lowering operations of the vicinity of both sides of the ram 19.

At a position near the metal bearing 29 at the other end of the rod member 27 described above, a first rotating member 43 is provided that penetrates the tube wall of the torsion bar 21 and projects outward. This rotating member 43 rotates integrally with one end of the torsion bar 21 via the rod member 27.

Corresponding to the first rotating member 43, a second rotating member 45 that rotates integrally with the other end of the torsion bar 21 is provided at a different phase from the other end. Then, the first and second rotating members 4
A sensor (detection device) 47, such as a differential transformer, a strain meter, or a pulse encoder, is provided between 3 and 45 in order to detect the relative rotation of both members. Therefore, the sensor 47 causes the torsion bar 21 to move in a direction in which the distance between the first and second rotating members 43 and 45 decreases or in a direction in which it increases.
can detect that it is twisted.

The detected value of the sensor 47 is input to a control device 49 such as a microcomputer shown in FIG. This control device 49 controls the torsion bar 21
The torsion direction of the torsion bar 21 is determined by comparing the detection value of the sensor 47 with the detection value of the first and second rotating members 43 and 45 when the torsion bar 21 is not twisted. The flow rate control valve, which will be described later, is controlled by determining the flow rate.

Next, the operation of the apparatus of this embodiment will be explained based on the electric circuit diagram and hydraulic piping diagram shown in FIG.

FIG. 3 shows a state in which the ram 19 is stopped.

Now, position the plate material between the movable mold attached to the lower surface of the ram 19 and the fixed mold attached to the upper surface of the fixed table 3, and place the solenoid SOL of the directional control valve 51.
1 is excited and the position of 1 is located in the center. Then, the pressure oil from the pump 53 is divided into left and right parts by an equal flow divider 55 and sent to the left and right fluid pressure cylinders 1.
The piston rods 15 and 17 are pushed down, and the hydraulic oil from the ports _{U 1 and U 2 is} returned to the oil tank 57 via the directional control valve 51, and the ram 19 is lowered.

While the ram 19 is descending, for example, if there is a difference in sliding friction between the left and right sides of the ram 19, one side of the ram 19 ( For example, the right side) will descend faster.

Therefore, the ram 19 will be tilted downward to the right in FIG. The amount of rotation of the left and right rotation levers 31 and 33 that are rotated is different. That is, the torsion bar 21
The right side of the torsion bar 21 is rotated more than the left side of the torsion bar 21, causing twisting of the torsion bar 21.

Therefore, the second rotating member 43 of the first rotating member 43 fixed to the rod member 27 fixed to the right tenon member 23 at the right end
The rotation in the same direction to the second rotation member 45 is delayed compared to the rotation in the counterclockwise direction in the figure.
In other words, a relative rotation occurs between both rotation members 43 and 45, and as a result, the first and second rotation members 43 and 45
The interval between the rotating members 43 and 45 becomes larger. If the ram 19 is inclined such that the left side of the ram 19 is downward, the distance becomes smaller, contrary to the above.

The amount of twist of the torsion bar 21 as described above is detected by the sensor 47, and the detected value is input to the control device 49 and compared with a reference value. As a result of the comparison, the control device 49 determines which side of the ram 19 is lowering faster, the left or the right, and issues a command to the coil section 6 of the left and right electromagnetic control flow rate control valves 59.
1, and in the case of the above example, the pressure oil supplied from the equal flow divider 55 to the hydraulic cylinder is discharged so that the flow rate is reduced on the right side, and the flow rate is increased on the left side. By Ram19
It works to slow down the right side's descent and accelerate the left side's descent.

In this way, the ram 19 can descend while maintaining a parallel attitude to the fixed table 3.

When the ram 19 is raised and returned to its original position, even if the ram 19 rises out of parallel due to the difference in frictional resistance between the sliding parts, it will not cause much of a problem, so a description of the operation will be omitted.

In the description of this embodiment, the press brake 1 has been described in which the ram 19 with a movable mold attached to the bottom surface descends and approaches the fixed table 3 with a fixed mold attached to the top surface, but it is possible to reverse the vertical relationship. It is obvious that the present invention can be applied to a press brake which is also used in a press brake, and it can also be used in a device that performs bending by approaching and separating in the horizontal direction.

Therefore, the present invention is not limited only to the above-mentioned embodiments, but can also be implemented in other embodiments.

As can be understood from the above description of the embodiments, according to the present invention, both sides of the torsion bar 21 rotate in conjunction with the vertical movement of the left and right sides of the ram 19, and the left and right sides of the ram 19 rotate. The configuration is such that the control device 49 controls the flow rate control valve 59 to control the flow rate of the pressure oil supplied to the left and right hydraulic cylinders 11 and 13 that move the ram 19 up and down by detecting the inclination as a torsion of the torsion bar 21, thereby preventing temperature changes. This has less influence and allows the overall configuration to be made smaller.

[Brief explanation of drawings]

FIG. 1 is a rear view of a press brake equipped with an embodiment of the present invention, FIG. 2 is a right side view of the same, and FIG.
The figure shows the electrical wiring and hydraulic piping diagram of the same as above. 1...Press brake, 3...Fixed table,
7, 9... Side plate, 11, 13... Hydraulic cylinder,
19... Ram, 21... Torsion bar, 27...
...rod member, 43...first rotating member, 43...second rotating member, 47...sensor, 49...control device, 59...flow control valve.

Claims (1)

[Claims] 1 Fixed table 3 fixed to left and right side plates 7 and 9
The ram 19 is provided with a ram 19 that is moved up and down by the operation of the hydraulic cylinders 11 and 13 attached to the side plates 7 and 9, and the hydraulic cylinders 11 and The press brake is equipped with a flow control valve 59 for controlling the flow rate of pressure oil supplied to the press brake 13, and the vicinity of both ends of the torsion bar 21, which is rotatably supported by the left and right side plates 7 and 9, is used as a press brake. , said ram 19
The torsion bar 21 is connected near both ends of the ram 19 so as to rotate in conjunction with the lifting and lowering operation of the ram 19.
A first rotating member 43 that rotates integrally with one end side is provided, and a second rotating member 45 that rotates integrally with the other end side of the torsion bar 21 is provided. A sensor 47 is provided to detect relative rotation with the rotation member 45 of the second rotation member.
A press brake characterized in that it is provided with a control device 49 that controls each of the flow rate control valves 59 based on the detection of the flow rate control valves 59.