JPH0757435B2 - Diction shock absorber for press machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die cushion cushioning device for a press machine capable of cushioning and noise reduction at the time of pin touch and at the time of upper limit of die cushion.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional die cushion cushioning device. In the figure, 10 is a die cushion, which is a machine frame 1
A cylinder 11 fixed to the cylinder 11, a piston 12 capable of airtightly sliding inside the cylinder 11, and a buffer tank 16 communicating with the cushion chamber 11D through a communication passage 15. The piston 12 is integrally connected to the cushion pad 14 via the upper piston rod 13, and the air pressure in the cushion chamber 11D is adjusted by the pressure regulator 17 (pressure indicator 77). In addition, 18 is a cushion pin and 19 is an air source.

Therefore, the cushion capacity is determined by the sectional area of the piston 12 and the air pressure in the cushion chamber 11D. Further, by making the buffer tank 16 have a relatively large capacity, the cushioning capacity during the downward movement of the cushion pad 14 can be made constant.

By the way, when the die cushion 10 reaches the upper limit, the piston 12 (13, 14 etc.) collides with the cylinder 11 at once, so the shock is very large. For this purpose, the die cushion cushioning device 20 of FIG. 7 is provided. The die cushion cushioning device 20 includes an oil pan 21, a retainer 22, and a stopper 24 that can be inserted into and taken out from a recess 27 of the retainer 22. The stopper 24 is integrated with the piston 12 via a lower piston rod 23 that penetrates the inside of the retainer 22.
2 is provided with a through hole 25. A preload is applied to the upper chamber of the oil pan 21. This preload is adjusted by the pressure regulator 28 (pressure indicator 78).

Accordingly, when the die cushion 10 approaches the upper limit as the cushion pad 14 rises after press molding, the stopper 24 moves from the direction shown by the two-dot chain line in FIG. Fit inside. Then, the oil is enclosed in the buffer chamber 27D surrounded by the recess 27 and the upper surface of the stopper 24. That is, since a downward braking force is applied to the stopper 24, shock and noise at the cushion upper limit can be mitigated. Since the compressed oil in the buffer chamber 27D passes through the throttle passage 26 and decreases with time, the cushion pad 14 can be finally returned to the predetermined position (upper limit).

On the other hand, when the slide rises after press molding, if the die cushion 10 is raised at the same time, the product may be crushed. Therefore, while the slide is raised to a certain height, a locking device that holds the cushion pad (14) at the lower limit (for example, the actual opening flat 2-87).
597).

[0007]

By the way, as the pressing speed, that is, the descending speed of the slide becomes higher, the impact and noise between the die cushion 10 and the slide become larger, which is a problem. In this regard, for example, Japanese Utility Model Laid-Open No. 2-87597 proposes a mechanism for applying hydraulic pressure to the upper chamber of the locking device at the time of pin-touch to positively lower the cushion pad to reduce the impact and noise. ing.

On the other hand, as the pressing ability and the cushioning ability are further increased, the impact and noise at the upper limit of the cushioning are increased as in the case of the above pin touch,
This is also a problem. That is, the shock absorber 2
0 (21, 22, 24) is premised on high-speed pressing, so buffering and noise reduction are reaching their limits. Further, regarding this point, the buffer mechanism at the time of pin touch in the above publication restrains the die cushion at a height where the slide is present, but if it is more than that, it will be released at once, so the shock and noise at the cushion upper limit rather It has been pointed out that it cannot be adopted from the standpoint of reducing the impact and noise when the cushion is at the upper limit because the number of cushions will increase.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a die cushion cushioning device for a press machine capable of significantly reducing shock and noise both at the time of pin touch and at the time of cushion upper limit. To do.

[0010]

According to a first aspect of the present invention, there is provided an oil pan, a retainer having a recess, and a stopper which can be inserted into and removed from the recess as the cushion pad moves up and down. In a die cushion cushioning device for a press machine, a pressure booster for boosting the oil in the oil pan and supplying it to a buffer chamber between the recess and the stopper through an oil supply passage provided in the retainer, and a cushion pin are used as cushions. A pin-touch timing signal generation means for grasping the timing of touching the pad, an upper limit front timing signal generation means for grasping the timing when the die cushion reaches the upper limit, and a die for the stopper based on the pin touch timing signal and the upper limit front timing signal. Booster to generate pressing and braking forces against the cushion By providing a control device for drive control, characterized by.

Further, the invention of claim 2 is provided with an oil temperature detecting means for detecting the temperature of the oil in the oil pan and a cushion pressure detecting means for detecting the capacity of the die cushion, and the control device is provided. It is characterized in that the pressure booster can be driven and controlled so that the amount of oil supplied to the buffer chamber can be increased or decreased depending on the oil temperature and the cushioning capacity.

[0012]

According to the first aspect of the present invention, the control device drives the pressure booster based on the pin touch timing signal. Then, the pressure oil (the oil discharged from the pressure booster) is supplied through the oil supply passage into the buffer chamber formed between the recess of the retainer and the stopper.
Therefore, since a pressing force is generated in the stopper, the die cushion is forcibly pulled down slightly. Therefore, the relative speed with respect to the slide descending speed becomes small, and the buffering and noise at the time of pin touch can be significantly reduced.

On the other hand, when the cushion approaches the upper limit,
Since the stopper fits into the recess, a buffer chamber is formed and buffered. At this time, when the cushion reaches the upper limit, a cushion upper limit timing signal is issued. Then,
The controller again drives the pressure booster to supply pressure oil to the buffer chamber. Therefore, the braking force in the opposite direction to the cushion raising force is applied to the stopper, and as a result, the impact and noise at the cushion upper limit can be significantly reduced.

That is, if the pin-touch timing and the cushion upper limit front timing are optimally set, both the pin touch timing and the cushion upper limit timing are ensured while making the best use of the cushion ability and ensuring the high-speed restoration operation of the cushion according to the press speed. The impact and noise at the time can be reduced at once.

Further, according to the second aspect of the invention, the control device drives the pressure booster so as to increase or decrease the amount of pressure oil supplied to the buffer chamber in response to a change in the oil temperature in the oil pan and a change in the die cushion capacity setting. Since the control is performed, even if the setting of the cushioning capacity is changed due to the change of the oil temperature with the operation time of the press and the change of the drawing mode of the press, the impact and the noise at both times can be stably maintained below a certain level.

[0016]

An embodiment of the present invention will be described below with reference to the drawings. In this cushion device, as shown in FIGS.
The pressure booster 30, the upper limit front timing signal generating means 73, the pin touch timing signal generating means 74, and the control device 70 are provided, and the pressure boosted by the pressure booster 30 is discharged into the buffer chamber 27D during the pin touch and the cushion upper limit. By supplying an appropriate amount of oil, that is, pressure oil, it is possible to significantly reduce the impact and noise at both times. Further, the cushion pressure detecting means 71 and the oil temperature detecting means 72 are provided, and the control device 70 is provided with a pressure booster 30 capable of automatically increasing or decreasing the amount of oil supplied to the buffer chamber 27D according to changes in cushion pressure and oil temperature. It is formed so that drive control can be performed, and regardless of changes in the press operation mode, it is possible to always achieve stable cushioning and noise reduction at both times.

Since the basic structures of the die cushion cushioning device 20 and the die cushion 10 are the same as those of the conventional example shown in FIG. 7, the same parts are designated by the same reference numerals and their description will be omitted. Simplify or omit.

First, the booster 30 includes a cylinder 31 forming a booster chamber 35 and a drive chamber 36, a piston 33 housed in the drive chamber 36, and the booster chamber 3 integrally with the piston 33.
5 consists of a piston rod 34 that can slide oil-tightly,
By supplying air of a predetermined pressure to the drive chamber 36,
Pressure oil can be supplied into the buffer chamber 27D through the check valve 37. The pressure booster 30 and the buffer chamber 27D are connected to each other through the opening 4
1 mainly faces the buffer chamber 27D as shown in FIG. 3, and the other opening 42 faces the outside of the oil pan 21 as shown in FIG. 1, so that the oil supply passage 4 formed through the retainer 22 is formed.
It is connected with 0.

The amount of oil supplied is determined by the piston rod 34
In FIG. 1, it is adjusted by the left and right strokes ST, that is, the driving time. In addition, the pressure increasing chamber 35 and the inside of the oil pan 21 are
The check valves 38 communicate with each other. Therefore, in a state where the drive air is not supplied into the drive chamber 36, the oil urged by the preload in the oil pan 21 does not flow into the check valve 38.
Is automatically supplied into the pressure increasing chamber 35 through. The preload is
It depends on the air pressure applied to the upper chamber in the oil pan 21 set in the pressure regulator 28. On the other hand, the compressed air for driving the booster 30 is supplied to the buffer tank 51.
From the (pressure indicator 79) to the switching valve 60 (solenoid 60)
S). The air pressure value is adjusted by the pressure regulator 50 (solenoid 50S). Therefore, by energizing and de-energizing the solenoid 60S, the 2-port switching valve 60 can be switched and the booster 30 can be driven / stopped.

Next, as shown in FIG. 6, the pin touch timing signal generating means 74 detects the timing (crank angle θ1) at which the cushion pin 18 of FIG. This is means for outputting the touch timing signal Pt (FIG. 2). Further, the upper limit front timing signal generating means 73 is a means for detecting that the die cushion 10 has risen after press molding to reach the upper limit front (crank angle θ2) and outputs the upper limit front timing signal Ph (FIG. 2). is there. Both means (7
3, 74) is formed from a known electronic timing signal generator in the case of this embodiment. The same applies to the upper limit detecting means 75 of the die cushion 10 shown in FIG. In addition, S and ST in FIG. 6 are slide strokes,
D / ST indicates a die cushion stroke.

In connection with this, 71 in FIGS. 1 and 2 is a cushion pressure detecting means for detecting the cushioning capacity from the air pressure of the buffer tank 16. Further, 72 is an oil temperature detecting means for detecting the oil temperature in the oil pan 21.

Subsequently, the control device 70 of FIG. 2 operates the booster 30 so as to generate a pressing force and a braking force against the die cushion at the stopper 24 based on the pin touch timing signal Pt and the upper limit front timing signal Ph. Drive control is performed, and in this embodiment, CPU, ROM, RA
It is constructed to also serve as the drive control panel for the entire press machine including M.

That is, as shown in FIG. 4, the control device 70 receives the pin touch timing signal Pt (ST.
13), the drive signal DRV of FIG. 2 is output to switch the switching valve 60 to drive the pressure booster 30 (ST14). Then,
The boosted oil (discharging oil) from the booster 30 is supplied into the buffer chamber 27D of FIG. 3 through the check valve 37 and the oil supply passage 40. Accordingly, the die cushion 1 is attached to the stopper 24.
Since a downward pressing force is applied against 0, the impact and noise when the cushion pin 18 and the cushion pad 14 are brought into contact with each other can be significantly reduced. After the press molding, when the die cushion 10 rises and the upper limit front timing signal Ph is input (ST16), the switching valve 60 is switched and the pressure booster 30 is driven again (ST17). Therefore, a downward braking force is generated at the stopper 24 against the die cushion 10. Therefore, both impact and noise at the time of cushion upper limit can be significantly reduced.

The pressure booster 30 is driven by supplying the pressure air from the buffer tank 51 into the drive chamber 36, but the pressure air in the drive chamber 36 is changed by the switching valve 60.
1 is released to the atmosphere through the piston rod 34, the piston rod 34 is pushed back to the right in FIG. 1 by the preload in the oil pan 21. That is, the oil in the oil pan 21 is replenished into the pressure boosting chamber 35 through the check valve 38 to prepare for the next drive of the pressure booster 30.

In addition, the control device 70 adjusts the amount of oil supplied to the pressure booster 30 with the die cushion capacity and the amount of oil supplied to the pressure booster 30 for the purpose of expanding the applicability, further reducing shock and noise, and rapidly returning the die cushion 10 due to the speeding up of the press. It is formed so that it can be automatically adjusted (increased or decreased) according to the oil temperature in the oil pan 21.

That is, when the cushion pressure signal Pc from the cushion pressure detecting means 71 and the oil temperature signal To from the oil temperature detecting means 72 are input as shown in ST10 to ST12 of FIG. 4, as shown in FIG. , For example, cushion pressure P
When c is large, the discharge amount (oil supply amount) is increased. The same applies when the oil temperature To is high. The amount of discharge is determined by the movable stroke, that is, the time for driving the booster 30, that is, the output time of the drive signal DRV in FIG. further,
In particular, in order to follow the increase and decrease of the cushion pressure Pc,
The control device 70 outputs the adjustment signal CNT shown in FIG. 2 to automatically adjust the pressure regulator 50, and the buffer tank 5
1. Adjust the internal air pressure.

In this embodiment, the oil supply amount is a two-stage switching system as shown in FIG. 5, but the cushion pressure Pc and the oil temperature To are automatically adjusted continuously or in an analog manner. Can be formed.

Further, reference numeral 76 indicated by a chain double-dashed line in FIG. 1 is an acceleration detecting sensor, which is means for detecting acceleration (impact degree) at the time of pin-touching the die cushion 10 and at the upper limit. In this embodiment, it is provided in order to obtain the optimum value of the amount of oil supplied to the buffer chamber 27D at the time of pin touch and before the upper limit. Of course, this acceleration detection sensor 7
It is also possible to automatically correct the amount of refueling with the detection signal of No. 6 so that the acceleration is minimized.

Next, the operation will be described. At the time of test operation, the acceleration detection sensor 76 is used to determine the amount of oil supply for minimizing the impact between the pin touch and the upper limit, and the amount is set in the control device 70. In addition, the reference cushion pressure (P
c) and the reference oil temperature (To) are set in the control device 70 in advance. Here, when the press is activated, ST10 in FIG. 4 is determined as NO, and therefore, a pinta touch is awaited in ST13.

When the pin touch timing signal Pt is input from the pin touch timing signal generating means 74 in accordance with the press molding, the control device 70 causes the drive signal DR.
V is output to switch the switching valve 60. Then, booster 3
0 is driven (ST14), and the oil supply passage 4 is inserted into the buffer chamber 27D.
Pressure oil is supplied through 0. The booster 30 is stopped at the set stroke 1, and the switching valve 60 is switched back. That is, since the pressure oil is supplied into the buffer chamber 27D as shown in FIG. 3, a downward pressing force is generated on the stopper 24. That is, since the die cushion 10 is forcibly pushed down, the relative speed between the cushion pin 18 and the cushion pad 14 is reduced, and as a result, the impact and noise during pin touch can be reduced.

On the other hand, after press molding, the die cushion 1
When 0 is before the upper limit, the control device 70 which receives the upper limit front timing signal Ph from the upper limit front timing signal generating means 73 drives the pressure booster 30 again to supply the pressure oil into the buffer chamber 27D (ST16, 17). ). Only the set stroke 2 is driven (ST18). This time, a braking force that resists the rising force of the die cushion 10 is applied to the stopper 24. Therefore, since the cushion pad 14 is prevented from rapidly increasing due to the cushion pressure in the cushion chamber 11D, the shock and noise at the cushion upper limit are added to the original effects of the die cushion cushioning device 20 in this case as well.
It is further reduced.

Thus, shock and noise reduction can be achieved both at the time of pin touch and at the time of cushion upper limit. Then, when the cushion reaches the upper limit (ST19), the control device 70 waits for the next pin touch (ST13).

In this case, when the set cushion pressure Pc changes depending on the press working mode or the oil temperature To changes with the operating time, the control device 70 detects the cushion pressure signal Pc from the cushion pressure detecting means 71 and the oil temperature detection. In response to the oil temperature signal To from the means 72, the drive stroke of the pressure booster 30 based on FIG. 5, that is, the drive signal DRV of FIG.
The output time setting of is automatically switched (ST11). Also,
The pressure regulator 50 is adjusted to automatically set the air pressure in the buffer tank 51 (ST12).

Therefore, according to this embodiment, the booster 3
0, the upper limit timing signal generating means 73, the pin touch timing signal generating means 74, and the control device 70 are provided.
Since the configuration is such that pressure oil is supplied into the buffer chamber 27D of the die cushion buffer device 20 at the time of pin-touch and before the upper limit, and the pressing force and the braking force against the die cushion 10 are added, the impact and noise at both times. And all of them can be reduced at once.

Further, the controller 70 controls the cushion pressure P
c, the amount of oil supplied to the buffer chamber 27D, that is, the pressing force and the braking force is automatically corrected based on the change in the oil temperature To, so that the press working mode is changed, the operating time is shortened, etc. , It is possible to always achieve a certain level of cushioning and noise reduction.

Further, when the cushion pressure Pc is changed, the air pressure for driving the pressure booster 30 is automatically adjusted by adjusting the pressure regulator 50. Therefore, the rapid restoration operation of the die cushion 10 accompanying the press speed increase can be performed. It does not interfere. Furthermore, since the pressure booster 30 recycles the oil in the oil pan 21 forming the die cushion shock absorber 20, the correct operation is guaranteed and it is economical.

[0037]

As described above, according to the invention of claim 1,
A pressure intensifier, a timing signal generating means before the upper limit, a pin touch timing signal generating means, and a control device are provided, and a pressing force and a braking force against the die cushion are supplied by supplying pressure oil into the buffer chamber at the time of pin touch and before the upper limit. Since the configuration is added, the impact and noise at the time of pin touch and at the time of the upper limit can be reduced all at once.

According to the second aspect of the present invention, the cushion pressure detecting means and the oil temperature detecting means are provided, and the control device automatically adjusts the amount of oil supplied to the buffer chamber by changing the cushion pressure oil temperature. Therefore, regardless of the mode of press operation and the length of the operating time, it is possible to achieve more stable cushioning and noise reduction.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram for explaining a control device and the like.

FIG. 3 is an enlarged view in which a part of the buffer chamber is also omitted.

FIG. 4 is a flow chart for explaining the same operation.

FIG. 5 is a diagram for explaining the switching operation of the oil supply amount based on the change in cushion pressure / oil temperature.

FIG. 6 is also a diagram for explaining timings at the time of pin touch and before the upper limit.

FIG. 7 is a diagram for explaining a conventional die cushion cushioning device.

[Explanation of symbols]

 10 Die Cushion 11 Cylinder 12 Piston 13 Upper Piston Rod 14 Cushion Pad 15 Communication Passage 16 Buffer Tank 17 Pressure Regulator 18 Cushion Pin 19 Air Source 20 Die Cushion Shock Absorber 21 Oil Pan 22 Retainer 23 Lower Piston Rod 24 Stopper 25 Through Hole 26 Throttle Flow passage 27 Recess 27D Buffer chamber 28 Pressure regulator 30 Pressure booster 31 Cylinder 33 Piston 34 Piston rod 35 Pressure booster chamber 36 Drive chamber 37 Check valve 38 Check valve 40 Oil supply passage 41 One opening 42 Other opening 50 Pressure regulator 50S Solenoid 51 Buffer tank 60 Switching valve 60S Solenoid 70 Control device 71 Cushion pressure detection means 72 Oil temperature detection means 73 Upper limit front timing signal generation means 74 pin Touch timing signal generating means 75 limit detecting means 76 acceleration sensor 77 pressure indicator 78 the pressure indicator 79 the pressure indicator

Claims (2)

[Claims] 1. A die cushion cushioning device for a press machine, comprising: an oil pan, a retainer having a recessed portion, and a stopper that can be inserted into and retracted from the recessed portion as the cushion pad moves up and down. A pressure booster for increasing the pressure of the oil in the oil pan and supplying it to the buffer chamber between the recess and the stopper through the oil supply passage provided in the retainer, and a pin touch timing for grasping the timing when the cushion pin touches the cushion pad. A signal generating means, an upper limit front timing signal generating means for grasping the timing when the die cushion reaches the upper limit, and a pressing force and a braking force against the die cushion are generated in the stopper based on the pin touch timing signal and the upper limit timing signal. And a control device for driving and controlling the pressure booster. And a die cushion cushioning device for a press machine. 2. An oil temperature detecting means for detecting the temperature of the oil in the oil pan and a cushion pressure detecting means for detecting the capacity of the die cushion are provided, and the controller is controlled by the oil temperature and the cushion capacity. The die cushion shock absorber for a press machine according to claim 1, wherein the pressure booster is formed so that the pressure booster can be driven and controlled so that the amount of oil supplied to the shock absorber can be increased or decreased.