JPH0534880Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for protecting a press machine when an overload is applied to the press machine.

[Conventional technology]

FIG. 2 shows an overload safety device previously provided by the present applicant as JP-A-62-161500, which is a multi-point press machine, in the illustrated example a two-point press having left and right point portions A and B This is applied to machines, and when eccentric loads P ₁ and P ₂ are applied to the slide 20, the overload can be released while maintaining the horizontal state of the slide 20.

The slide 20 is connected to the lower ends of two connecting rods 21A and 21B, and as a drive shaft such as a crankshaft rotates and these connecting rods 21A and 21B move up and down, the slide 20 is guided by the slide gib 22. It moves up and down while pressing. Inside the slide 20, cylinders 23A and 23B are arranged for each of the connecting rods 21A and 21B, and the lower end ball portions 26 of the connecting rods 21A and 21B are located in the hydraulic chambers 24A and 24B of these cylinders 23A and 23B.
Pressure receiving members 25A and 25B receiving A and 26B are housed so as to be vertically movable.

Upward surfaces 27A, 2 of pressure receiving members 25A, 25B
7B and the downward facing surface 28A of the hydraulic chambers 24A, 24B,
Seal portions 29A and 29B that can be opened and closed are formed with 28B, and the hydraulic chambers 24A and 24B have a first chamber 3 partitioned by the bottom surfaces of the pressure receiving members 25A and 25B.
0A and 30B are provided. Furthermore, the first room 30
At the upper part of A, 30B, the seal parts 29A, 29
Second chambers 31A and 31B are provided at the bottom of B,
A third chamber 32 is located above the seal portions 29A and 29B.
A and 32B are provided.

First chamber 30A, 30B and second chamber 31A, 31B
Therefore, when the pressure receiving members 25A and 25B are slightly lowered, the first chamber 3
A very small amount of oil, that is, an amount insufficient to eliminate the overload, flows into the second chambers 31A, 31B from 0A, 30B. This is done by making the gap between the outer circumferential surface of the pressure receiving members 25A, 25B and the inner circumferential surface of the cylinders 23A, 23B very small, or by providing a sealing member on the outer circumferential surface of the pressure receiving members 25A, 25B. . When the pressure receiving members 25A, 25B are slightly lowered, the seal portions 29A, 29B open.

As described above, the first chambers 30A, 30B and the second chamber 31 are provided for each of the left and right hydraulic chambers 24A, 24B.
Among A and 31B, the first chamber 30A and the second chamber 31B
are connected by a circuit 34, and the first chamber 30B and the second chamber 31A are connected by a circuit 35. Therefore, the first chamber 30A, 30B, the second chamber
The chambers 31A and 31B are cross-connected to each other by two circuits 34 and 35. A hydraulic supply circuit 37 extending from an oil tank 36 is connected to the circuits 34 and 35, and a booster pump 41 is connected to this hydraulic supply circuit 37, which includes check valves 38, 39, and 40.
An air source 44 is connected to the booster pump 41 via a switching valve 42 and a regulator 43. Also,
An oil relief circuit 45 is provided in the third chambers 32A and 32B.
is connected, and this oil relief circuit 45 is connected to the oil tank 3.
Extends to 6.

the hydraulic supply circuit 37, the booster pump 41,
The first chamber 30 is connected to the first chamber 30 through two circuits 34 and 35 by a switching valve 42, a regulator 43, an air source 44, etc.
A hydraulic pressure supply means 46 is configured to supply hydraulic pressure to the first chambers 30A and 30B, and by reciprocating the booster pump 41, hydraulic pressure of the same pressure is supplied to the first chambers 30A and 30B.

In the press machine in which the slide 22 is provided with the left and right point portions A and B as described above, the connecting rod 21
The press pressure acting on the pressure receiving members 25A and 25B is applied to the first chambers 30A and 30B.
The pressing operation is performed by acting on the slide 20 via hydraulic pressure. During this pressing operation, if an overload eccentric load P ₁ is applied to one of the left and right point portions A and B, for example, when a blank with a thickness greater than a predetermined thickness is supplied to one of the right and left point portions A and B, the relative At this time, the pressure receiving member 25A is slightly lowered relative to the slide 20 and the seal portion 29A is opened, and at this time, as described above,
The first chamber 30A and the second chamber 31A are almost in a disconnected state, and an amount of oil sufficient to eliminate the overload load _P1 does not flow from the first chamber 30A to the second chamber 31A.

When the seal portion 29A opens, the oil in the second chamber 31A flows out into the oil tank 36 via the third chamber 32A and the oil return circuit 45, and when the oil pressure in the second chamber 31A decreases in this way, the oil in the second chamber 31A flows out to the oil tank 36 through the oil return circuit 45. The oil in the first chamber 30B also flows out to the oil tank 36 via the circuit 35, the second chamber 31A, the 30th chamber 32A, and the oil relief circuit 45. As a result, due to the decrease in the oil pressure in the first chamber 30B, the pressure receiving member 25B is lowered and the seal portion 29B is opened, and the oil in the second chamber 31B flows out into the oil tank 36 via the third chamber 32B and the oil relief passage 45. do. When the oil pressure in the second chamber 31B decreases, the oil in the first chamber 30A at the right point A flows out into the oil tank 36 via the circuit 34, the second chamber 31B, the 30th chamber 32A, and the oil relief circuit 45. . As a result, the left and right pressure receiving members 25A, 25B are lowered, the overload safety device is activated to break, and the press machine is protected from overload.

As described above, even if the eccentric load P ₁ acts, the pressure receiving member 25A does not immediately descend to the lowering limit relative to the slide 20, in other words, the slide 2
0 does not tilt upward to the right, and the overload safety device breaks down in the first chambers 30A, 30B and the second chamber 31.
A and 31B are cross-connected, so the left and right slides are performed almost simultaneously, so the slide 20
is maintained in a horizontal state, thereby solving the problem of damage to the slide gib 22 due to tilting of the slide 20.

[The problem that the idea aims to solve]

Due to the characteristics of the press process in transfer press machines and progressive press machines,
The magnitude of the press pressure acting on the left and right point portions A and B is different, and therefore the first chambers 30A and 30
It is necessary to vary the magnitude of the hydraulic pressure supplied to B in accordance with the press pressure so that the breaking force of the overload safety device can be appropriately set for each of the left and right point portions A and B.

However, in the conventional device shown in FIG. 2, the first chamber 30A,
30B are supplied with the same hydraulic pressure by the same hydraulic pressure supply means 46, so the structure has not been able to meet the above requirements.

The purpose of this invention is to maintain the advantages of the conventional device shown in Fig. 2, and also to make it possible to make the hydraulic pressure in the first chamber different for each chamber. The purpose of the present invention is to provide an overload safety device that can be applied to machinery.

[Means to solve the problem]

Therefore, in the overload safety device for a press machine according to the present invention, a slide is connected to the lower ends of a plurality of connecting rods that move up and down by rotation of a drive shaft, and a hydraulic chamber is provided for each of the connecting rods inside the slide. A pressure receiving member is provided which is housed in the hydraulic chamber so as to be movable up and down and receives the press pressure of the connecting rod.The upward facing surface of the pressure receiving member and the downward facing surface of the hydraulic chamber form a seal portion which can be freely opened and closed. A first chamber partitioned by the bottom surface of the pressure-receiving member is provided in the chamber, and a second chamber is provided above the first chamber and below the seal portion and is substantially cut off from the first chamber, and , a third chamber to which an oil relief circuit is connected is provided in the upper part of the seal part, and the first and second chambers of the two hydraulic chambers are cross-connected to each other by two circuits, and the two circuits are The overload safety device for a press machine is characterized in that the hydraulic pressure supply means is provided for each of the two cross-connection circuits.

[Effect]

In this way, in the present invention, a hydraulic pressure supply means is provided for each of the two circuits for cross connection.
The size of the oil pressure in the chamber can now be set for each first chamber, and the size of the oil pressure in each first chamber can be adjusted arbitrarily, so the minimum size suitable for transfer press processing and progressive press processing can be adjusted. You can now set overload.

Additionally, if a hydraulic pressure sensor is installed in each of the two circuits, the press pressure during press work can be measured for each first chamber, making it possible to check the press pressure during transfer press work or progressive press work. I can do it.

〔Example〕

FIG. 1 shows an apparatus according to an embodiment of the present invention. In the following description, the same members as those in the conventional device shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will be simplified or omitted. In addition, in this embodiment, the first chambers 30A and 30B
Seal members 33A, 33B are provided on the outer peripheral surfaces of the pressure receiving members 25A, 25B in order to substantially shut off the second chambers 31A, 31B.

The first chamber 30A of the left and right hydraulic chambers 24A, 24B,
Of the two circuits 34 and 35 that cross-connect 30B and the second chambers 31A and 31B, the circuit 34
The hydraulic pressure supply circuit 1A is connected to the circuit 35, the hydraulic pressure supply circuit 1B is connected to the circuit 35, and the check valves 2, 3,
These oil pressure supply circuits 1A and 4 and 5 are provided with
1B extends to the oil tank 36. Hydraulic supply circuit 1
A booster pump 6A is connected to A, and a booster pump 6B is connected to the hydraulic pressure supply circuit 1B, and an air source 9 is connected to these booster pumps 6A and 6B via switching valves 7A and 7B and regulators 8A and 8B. Connected.

Hydraulic pressure supply circuit 1A, booster pump 6A, switching valve 7A, regulator 8, and air source 9 constitute hydraulic pressure supply means 10A.
A is connected to the circuit 34. In addition, a hydraulic supply circuit 1B, a booster pump 6B, a switching valve 7
B, regulator 8B, and air source 9 constitute a hydraulic pressure supply means 10B, and this hydraulic pressure supply means 10B
is connected to the circuit 35. The circuit 34 is provided with an oil pressure sensor 11A, and the circuit 35 is provided with an oil pressure sensor 11B.

As described above, in this embodiment, the hydraulic pressure supply means 10A,
10B, the press pressure acting on one of the left and right point portions A and B, for example, the right point portion A, may become large in order to perform transfer press processing or progressive press processing. If it is predicted that the press pressure acting on the left point part B will become smaller, the first air pressure supplied by the booster pump 6A can be increased by increasing the air pressure set by the regulator 8A. By increasing the oil pressure in the chamber 30A and reducing the air pressure set by the regulator 8B, the oil pressure in the first chamber 30B supplied by the booster pump 6B is reduced. As a result, the first chamber 30 of point portions A and B
The magnitude of the hydraulic pressure at points A and 30B can be adjusted according to the press pressure generated during press work, and the press pressure at point parts A and B during press work is controlled via the oil in the first chambers 30A and 30B. It is measured by oil pressure sensors 11A and 11B, and the press pressure at each point A and B can be confirmed.

If an overload set by the oil pressure in the first chambers 30A, 30B is applied to either the left or right point portions A, B during press work, the overload will be removed in the same manner as the conventional device shown in Fig. 2 described above. The load safety devices are ruptured almost simultaneously on the left and right sides, and the slide 20 remains in a horizontal state.

As described above, in this embodiment, the left and right first chambers 30
Since the oil pressure of A and 30B can be set separately, the overload of point parts A and B can be set to the minimum value suitable for transfer press processing and progressive press processing, and therefore the mold can be prevented from overloading. will be able to properly protect the

Although the present embodiment described above was applied to a two-point press machine, the present invention can also be applied to a four-point press machine having two drive shafts such as crankshafts. Furthermore, the press machine of this embodiment has a connecting rod 21.
A, 21B and pressure receiving members 25A, 25B are connected by ball portions 26A, 26B, but the present invention can also be applied to a press machine that uses wrist pins instead. . Furthermore, although the oil pressure sensors 11A and 11B are used in this embodiment, they may be omitted. However, if the oil pressure sensors 11A and 11B are used, it is possible to measure and confirm the press pressure during the press operation as described above.

[Effect of idea]

According to the present invention, the advantages of the conventional device shown in Fig. 2 can be maintained as is, and the magnitude of the hydraulic pressure in the first chamber can be made different for each first chamber, allowing transfer press processing and progressive press processing. It is now possible to set overload settings that are suitable for

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram showing a device according to an embodiment of the present invention, and FIG. 2 is a diagram similar to FIG. 1 showing a conventional device. 1A, 1B...Hydraulic pressure supply circuit, 6A, 6B...
Booster pump, 10A, 10B...Hydraulic pressure supply means, 11A, 11B...Hydraulic pressure sensor, 20...Slide, 21A, 21B...Connecting rod, 23A, 2
3B...Cylinder, 24A, 24B...Hydraulic chamber,
25A, 25B...Pressure receiving member, 27A, 27B...
...Upward facing surface, 28A, 28B...Downward facing surface, 29
A, 29B... Seal part, 30A, 30B... First chamber, 31A, 31B... Second chamber, 32A, 32
B... Third chamber, 34, 35... Circuit for cross connection, 36... Oil tank, 45... Oil relief circuit.

Claims (1)

[Scope of utility model registration request] A slide is connected to the lower end of a plurality of connecting rods that move up and down as the drive shaft rotates, and inside this slide there is a hydraulic chamber for each of the connecting rods. a pressure-receiving member that receives the pressure, an upward surface of the pressure-receiving member and a downward surface of the hydraulic chamber form a seal that can be opened and closed, and the hydraulic chamber is provided with a first chamber partitioned by the bottom surface of the pressure-receiving member. In addition, a second chamber is provided above the first chamber and below the seal portion, and is substantially cut off from the first chamber, and a third chamber is connected to an oil relief circuit at the top of the seal portion. established,
The first and second chambers of the two hydraulic chambers are connected to each other.
An overload safety device for a press machine in which two circuits are cross-connected and a hydraulic pressure supply means is connected to these two circuits, characterized in that the hydraulic pressure supply means is provided for each of the two cross-connection circuits. Overload safety device for press machines.