JPS6153158B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a safety device that protects a press device when an overload is applied to the press device.

[Background technology and its problems] As an example of overload in a mechanical press, there is a press device that presses a blank using an upper die attached to the lower surface of a vertically moving slide and a lower die attached to the upper surface of a bolster. In this case, a plurality of blanks or blanks having a predetermined thickness or more are supplied. In this case, there is a risk that the device will be damaged due to overload, so the present applicant's Japanese Patent Publication No. 16388/1983 is known as an overload safety device that protects the members that make up the press machine from this overload. It is being This device has the following configuration and function.

In FIG. 2, the slide 42 is attached to a connecting rod 41 that is connected to a drive shaft that is a crankshaft and reciprocates up and down.
Slide this press pressure under the press pressure of 4
2 is provided. Further, a hydraulic chamber 44 is formed inside the slide 42, and the pressure receiving member 43 is arranged in this hydraulic chamber 44 so as to be vertically movable. The pressure receiving member 43 has a stepped shape with a large lower part, and the upward facing surface 43A of the stepped part and the downward facing surface 44A of the hydraulic chamber 44 come into contact with each other as the pressure receiving member 43 moves up and down, and this contact and separation part causes the up and down movement of the pressure receiving member 43. The seal part 45 opens and closes as the oil changes, and an oil escape path is connected to the seal part 45.

Oil at a constant pressure is supplied to the hydraulic chamber 44,
When the blank is pressed by lowering the connecting rod 41 and the slide 42, the press pressure of the connecting rod 41 and the pressure receiving member 43 is transmitted to the slide 42 via the hydraulic pressure of the hydraulic chamber 44. When an overload is applied to the slide 42, the pressing force of the connecting rod 41 causes the pressure receiving member 43 to move downward against the hydraulic pressure of the hydraulic chamber 44, thereby opening the seal portion 45.
The oil in the hydraulic chamber 44 passes through this seal portion 45 and is released into the oil release path. As a result, connecting rod 4
1 can be moved relative to the slide 42, and overload can be absorbed.

In the conventional device described above, by the time the blank that caused the overload is removed and the next press work is performed, the seal portion is closed and oil at a constant pressure is returned to the hydraulic chamber. There must be. Conventionally, a spring-type or air piston-type mechanical lift device has been provided below the pressure-receiving member in order to return the pressure-receiving member upward and return oil to the hydraulic chamber. For this reason, it is necessary to install the lift device inside the slide separately from the internal mechanism of the slide, and it is also necessary to manufacture parts of the lift device and assemble it into the inside of the slide.

[Object of the Invention] The object of the present invention is to provide an overloading device for a press that allows the upward return movement of the pressure-receiving member to be carried out without the use of a mechanical lifting device, thus eliminating the need for a conventional lifting device inside the slide. Provides load safety equipment.

[Means and effects for solving the problem] Therefore, the configuration of the present invention is such that a slide is attached to a connecting rod connected to a drive shaft, and a pressure receiving member is provided inside the slide to receive the pressing pressure of the connecting rod. , by arranging this pressure receiving member in a hydraulic chamber formed inside the slide so as to be able to move up and down, the upward surface of the pressure receiving member and the downward surface of this hydraulic chamber form a seal that can be opened and closed, and the hydraulic chamber When the press equipment is overloaded, an oil pressure is supplied to transmit the press pressure of the pressure-receiving member to the slide, and an oil release path is connected to the seal part to release the oil in the hydraulic chamber through the seal part that opens at the time of overload. In the safety device, a fluid pressurizing means for applying pressure to oil in an oil tank provided in the oil relief path is used, and when an overload is released, the pressure of the fluid pressurizing means is used to transfer the oil in the oil tank to the oil relief path. through the seal portion and the hydraulic chamber, thereby causing the pressure receiving member to return upward;
Moreover, it is characterized in that this return movement can be performed quickly.

[Embodiment] The drawing is a longitudinal cross-sectional view showing an embodiment of the device according to the present invention. It reciprocates up and down by rotating the crankshaft. An upper mold (not shown) is fixed to the lower surface of the slide 2, and the blank is pressed into a predetermined shape by the lower mold fixed to the upper surface of a bolster (not shown) and this upper mold as the slide 2 descends.

The lower end ball portion 1A of the connecting rod 1 is inserted into a recess 3 formed in the slide 2, and ring-shaped restraining members 4 and 5 fitted and fixed in the upper part of the recess 3 restrain the upper spherical surface portion of the ball portion 1A. The connecting rod 1 and the slide 2 are connected by this. A ball receiving member 6 is disposed at the lower part of the recess 3, and a lower spherical portion of the ball portion 1A is fitted into a spherical recess 6A formed on the upper surface of the ball receiving member 6. As a result, the connecting rod 1 comes into spherical contact with the ball receiving member 6, and the rotation of the crankshaft is converted into vertical reciprocating motion of the slide 2. The ball receiving member 6 is a pressure receiving member that receives the press pressure of the connecting rod 1, and this press pressure is transmitted from the spherical contact portion.

The ball receiving member 6 has a stepped short cylindrical shape consisting of a lower large diameter portion 6B and an upper small diameter portion 6C.
B faces a hydraulic chamber 7 formed continuously at the lower part of the recess 3, and the ball receiving member 6 is arranged in this hydraulic chamber 7 inside the slide 2 so as to be vertically movable. A ring-shaped closing member 9 is attached with bolts 8 to the bottom surface 3A of the recess 3 formed to have a larger diameter than the hydraulic chamber 7, and the outer peripheral surface of the small diameter portion 6C of the ball receiving member 6 is connected to the inner surface of this closing member 9. The ball receiving member 6 moves up and down with respect to the hydraulic chamber 7 while being sealed on the peripheral surface.

Since the inner diameter of the closing member 9 is smaller than the diameter of the hydraulic chamber 7, the inner diameter portion 9A of the closing member protrudes inward of the hydraulic chamber 7, so that the lower surface of the inner diameter of the closing member 9 directs the hydraulic chamber 7 downward. A surface 7A is formed. On the other hand, the large diameter portion 6B of the stepped ball receiving member 6
The upper surface forms an upward surface 6D of the ball receiving member 6, and these upward surfaces 6D and downward surfaces 7A
and face each other in the vertical direction. As the ball receiving member 6 moves up and down, these surfaces 6D and 7A come into contact with and separate from each other, so a sealing portion 10 is formed between the ball receiving member 6 and the closing member 9. It opens and closes as it moves.

An annular oil circulation passage 11 is formed in the lower part of the inner peripheral surface of the closing member 9, and an oil passage 12 formed in the closing member 9 is connected to this oil circulation passage 11. The oil passage 12 having a length in the radial direction of the closing member 9 is bent downward by a bending passage 13, and the bending passage 13 is connected to the upper end of the tube member 14. This tube member 14 is the slide 2
The lower end of the tube member 14 projects into an oil tank 15 formed inside the slide 2. Above circuit oil passage 1
1. An oil escape route 16 is formed by the oil passage 12, the bent path 13, and the pipe member 14, and an oil tank 15 is provided at the end of the oil escape route 16. Since the starting end of the oil escape path 16 is connected to the seal portion 10, when this seal portion 10 is opened, the oil in the hydraulic chamber 7 is released to the oil escape path 16 through the seal portion 10.

An oil passage 17 is formed vertically inside the ball receiving member 6 near the end thereof, and the lower end of this oil passage 17 faces the hydraulic chamber 7 because it opens on the lower surface of the ball receiving member 6. The upper end of the oil passage 17 is bent in the direction of the outer diameter of the ball receiving member 6, and is connected to a communication passage 18 that is formed to penetrate inside the closing member 9 in the inner and outer directions. A sealing member 19 is provided in the communication path 18.
A connecting path 20 formed in the slide 2 is connected to the slide 2.
A joint member 21 is attached to this sealing member 19 which is tightly fitted and fixed. The joint member 21 is connected to an oil pump 22 installed in the oil tank 15 via a pipe line 23, so that the oil tank 15
The oil is in the pipe line 23, the joint member 21, and the connecting line 2.
The hydraulic pressure is supplied to the hydraulic chamber 7 through a hydraulic pressure supply path 24 that includes 0, a communication path 18, and an oil path 17. In this case, the oil supplied to the hydraulic chamber 7 is increased in pressure by the oil pump 22 to a constant pressure necessary for press working. In this embodiment, the opening of the oil tank 15 formed in the side surface of the slide 2 is connected to the oil pump 2.
2 and thus the oil pump 22
also serves as a lid member for the oil tank 15.

An air reservoir 25 is formed in the side surface of the slide 2 in the upper part of the oil tank 15, and the air reservoir 25 is connected to the oil tank 15 via a communication path 26. A connecting port 28 is formed in the lid member 27 that closes the opening of the air reservoir 25, and a conduit 29 connected to the air compressor is connected to the connecting port 28. The air compressor, the pipe line 29, the connecting port 28, the air reservoir 25, and the connecting passage 26 constitute a fluid pressurizing means 30 for pressurizing the oil in the oil tank 15, and the air pressure in the air reservoir 25 is controlled by the air compressor. The air pressure is increased to a normal pressure of about 5 kg/cm ² depending on the air conditioner, and this air pressure is passed through the communication passage 26 to the oil tank 1.
Acts on 5 oils.

Next, we will discuss the effect.

When pressing the blank supplied between the upper mold and the lower mold, oil in the oil tank 15 is supplied to the hydraulic chamber 7 via the hydraulic pressure supply path 24,
Since the hydraulic chamber 7 is filled with oil at a constant pressure, the ball receiving member 6 is in the raised position, and therefore the seal portion 10 is closed. When the connecting rod 1 and the slide 2 are lowered for press working, the ball receiving member 6 as a pressure receiving member receives the press pressure of the connecting rod 1, and this pressing pressure is transmitted to the slide 2 via the hydraulic pressure of the hydraulic chamber 7. The blank is pressed at the bottom dead center of the slide 2.

When an overload occurs on the slide 2 due to a plurality of blanks or blanks with a predetermined thickness or more being supplied between the upper and lower dies, the ball receiving member 6 moves toward the connecting rod 1 while the slide 2 does not descend any further. Due to the pressing force, it moves downward in the hydraulic chamber 7 against the hydraulic pressure in the hydraulic chamber 7. As a result, the upward surface 6D of the ball receiving member 6
is separated from the downward facing surface 7A of the hydraulic chamber 7, and the seal portion 10 is opened. Therefore, the oil in the hydraulic chamber 7 escapes to the circulation oil passage 11 through the gap 31 provided on the outer peripheral side of the large diameter portion 6B of the ball receiving member 6 and the open seal portion 10, and furthermore, this oil The oil flows through the oil escape path 16 and flows into the oil tank 15. Therefore, the hydraulic pressure in the hydraulic chamber 7 decreases, the ball receiving member 6 descends relative to the slide 2, and the ball receiving member 6 moves downward by the depth of the hydraulic chamber 7, thereby avoiding overload.

After the connecting rod 1 and slide 2 are raised, the blank that caused the overload is removed, and oil must be returned to the hydraulic chamber 7 before the next press process is performed. is carried out as follows.

Since air pressure is applied to the oil in the oil tank 15 by the fluid pressurizing means 30, the oil in the oil tank 15
The oil flows through the pipe member 14, the bent path 13, and the oil passage 1.
2. The oil flows backward through the circuit 11 and is constantly returned to the seal portion 10 and the hydraulic chamber 7. In this case, the hydraulic pressure of the oil pressurized by air pressure acts on the upper surface 6D of the large diameter portion 6B of the ball receiving member 6 and the lower surface of this large diameter portion 6B, but the lower surface of the large diameter portion 6B Since the area is larger by the cross-sectional area of the small diameter portion 6C, in the end,
An upward moving force equal to the oil pressure multiplied by the cross-sectional area of the small diameter portion 6C acts on the ball receiving member 6, and as a result, the ball receiving member 6 quickly returns upward, and the hydraulic chamber 7 Most of the space is filled with the oil that has flowed back, and the seal portion 10 is closed. In addition,
In this case, the oil tank 1 is
5 is supplied to the hydraulic chamber 7 via the hydraulic pressure supply path 24.
Therefore, as described above, the seal part 1
By closing 0, only a small amount of oil is supplied from the hydraulic pressure supply path 24 to the hydraulic chamber 7, and the hydraulic pressure in the hydraulic chamber 7 increases to a predetermined constant force, and everything returns to the desired state in a short time. . Further, the pressure of the air reservoir 25 that pressurizes the oil in the oil tank 15 is, for example, 5 kg/cm ²
Since a normal pressure of about 100 mL is sufficient, an air pressure source permanently installed in a factory or the like can be used as the pressure source for the air reservoir 25, and there is no need to prepare a special air pressure source.

In this embodiment, the oil tank provided in the oil release path was formed inside the slide, but in the device according to the present invention, the oil tank is provided in the oil release path led out from the slide, and the oil tank is provided outside the slide. The present invention can also be applied to a case in which an oil tank is provided in the oil relief path, and if necessary, it is sufficient to include a fluid pressurizing means for applying pressure to oil in an oil tank provided in an oil escape path and returning the oil to the seal portion and the hydraulic chamber. Further, the device according to the present invention can be applied to a press device in which a structure other than the internal structure of the slide shown in this embodiment is adopted, and if necessary, the device is arranged in a hydraulic chamber inside the slide so as to be movable up and down. Any press device can be applied as long as the upward facing surface of the pressure receiving member and the downward facing surface of the hydraulic chamber form a seal portion that can be opened and closed, and an oil release path is connected to this seal portion. In addition, in this embodiment, the pressurized fluid of the fluid pressurizing means is air, and although other fluids can be used as the pressurized fluid, by using air as in this embodiment, it is easier to handle, and piping is easier. System simplification can be achieved.

[Effects of the Invention] According to the present invention, the mechanical lift device conventionally provided inside the slide can be abolished, and therefore the internal structure of the slide can be simplified and workability such as assembly work can be improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an embodiment of the device according to the present invention, and FIG. 2 is a vertical sectional view showing a conventional example. DESCRIPTION OF SYMBOLS 1... Connecting rod, 2... Slide, 6... Ball receiving member which is a pressure receiving member, 6D... Upward surface, 7...
...Hydraulic chamber, 7A...Downward surface, 10...Seal portion, 15...Oil tank, 16...Oil escape route,
30...Fluid pressurizing means.

Claims (1)

[Claims] 1. A slide is attached to a connecting rod connected to the drive shaft, a pressure receiving member is provided inside the slide to receive the pressing pressure of the connecting rod, and this pressure receiving member can be moved up and down into a hydraulic chamber formed inside the slide. By arranging the pressure-receiving member in an upward direction and a downward-facing surface of the hydraulic chamber, a seal portion that can be opened and closed is formed, and hydraulic pressure for transmitting the press pressure of the pressure-receiving member to the slide is supplied to the hydraulic chamber, and In an overload safety device for a press device, in which an oil relief path is connected to the seal portion to release oil in the hydraulic chamber through the seal portion that opens during overload, pressure is applied to oil in an oil tank provided in the oil relief path. An overload safety device for a press machine, comprising: a fluid pressurizing means for returning oil to the seal portion and the hydraulic chamber.