JPH0245560B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press machine that mainly performs drawing processing, and more specifically, the present invention relates to a press machine that mainly performs drawing processing, and more specifically, a press machine that is capable of performing multi-stage forming processing within one stroke of a slide that can freely move up and down. This relates to press machines.

Conventionally, when press-molding a product that is shaped like a bowler hat and has holes in its flange or top surface, a press machine with a coating stand is required, and each press machine is required to transfer the semi-finished product to each press machine. A transfer device was needed to sequentially transfer the materials. That is, in the past, a press machine was required for each of a plurality of processing steps, and a transfer device, a robot, etc. were also required. Therefore, the equipment costs are high and a relatively large area is required for arranging a plurality of press machines.

The present invention was developed in view of the above-mentioned conventional problems, and its purpose is to provide a press machine that can improve the finishing accuracy of processed products by setting an appropriate initial pressure for processing.

In order to achieve the above objects, the present invention generally comprises a lower cushion device installed on the bed of a press machine and an upper cushion device installed on a slide so as to be able to rise and fall freely, and each cushion has a double structure. The pressure source of the device is an air-hydraulic conversion mechanism that converts air pressure into hydraulic pressure. Further, in order to accommodate various types of processing, the pressure of each hydraulic mechanism in the cushion device is individually adjustable.

The drawings illustrate embodiments of the invention. FIG. 1 is a front view showing an example of a press mechanism in which the present invention can be carried out.

FIG. 2 shows an enlarged sectional view of the lower cushion device of the press machine shown in FIG. In addition, in FIG. 2, different states are shown on the left and right with the center line as a border.

FIG. 3 shows an enlarged sectional view of the front lower cushion device. Note that the bellows portion is shown with a portion cut away.

FIG. 4 is a diagram showing hydraulic circuits of the upper cushion device and the lower cushion device, and a pneumatic/hydraulic conversion circuit for adjusting and controlling the hydraulic circuits using pneumatic pressure.

FIG. 5 is a perspective view showing an example of a product processed by the press machine.

FIG. 6 is a sectional view of a mold for molding the product shown in FIG. 5.

FIG. 7 shows another embodiment of the air-hydraulic conversion circuit shown in FIG. 4.

Hereinafter, embodiments of the present invention will be described in detail using the above drawings.

First, the overview of the press machine shown in Fig. 1, the explanation of the upper cushion device shown in Fig. 2, the explanation of the lower cushion device shown in Fig. 3, and then the pneumatic hydraulic system that operates the upper cushion device and the lower cushion device. Perform in the order of the conversion circuit diagram.

Next, a case in which a product as shown in FIG. 5 is molded using the above-mentioned upper cushion device and lower cushion device will be described with reference to FIG. 6.

Another embodiment of the air-hydraulic conversion circuit shown in FIG. 4 will be described with reference to FIG. 7.

Referring to FIG. 1, the press machine 1 according to the present invention has a bed 5 fixed to the lower side of a C-shaped frame 3, and a bolster 7 mounted on the bed 5, like a general press machine. are doing. Bed 5 above
A slide 9 is mounted above the frame 3 so as to be able to move up and down, and a slide drive device 11 for moving the slide 9 up and down is mounted on the upper part of the frame 3.

With the above configuration, the upper mold 13 is attached to the lower surface of the slide 9.
is mounted, and the lower die 15 is mounted on the bolster 7, and press working is performed. In addition, the upper mold 13 and the lower mold 15
A mold unit (die set) in which the die set and the die set are assembled may be mounted on the bolster 7 for processing. By moving the slide 9 up and down by the slide drive device 11, a plate-shaped workpiece (not shown in FIG. 1) placed on the lower die 15 is pressed. In this example, a mold unit is used. Furthermore, in this embodiment, the crankshaft 17
In this example, the slide 9 is moved up and down by being rotated by a motor (not shown). However, the present invention is not limited to the above embodiment, and the slide drive device may be a device such as a hydraulic cylinder, for example.
That is, any structure that allows the slide 9 to be moved up and down may be used.

Next, the upper cushion device shown in FIG. 2 will be explained. The slide 9 is equipped with a plurality of (double in this embodiment) upper cushion devices 19.

The slide 9 has a large diameter recess 9 that opens downward.
A is bored in the upper part of the large diameter recess 9A, and a small diameter recess 9 into which a cylinder cap 39 etc. is to be fitted is formed.
B is installed consecutively. A first cylinder 21 having an inwardly protruding flange portion 21F on its upper portion is fitted into the large-diameter recess 9A and fixed by a plurality of bolts 23. A substantially cylindrical first piston 25 is fitted into the first cylinder 21 so as to be movable up and down.

The first cylinder 21 and the first piston 25
is the upper cushion device 19 together with the first fluid chamber 35.
This constitutes the first fluid pressure device in.

The upper portion of the first piston 25 is guided by a seal ring 27 that is fitted and fixed to the inner peripheral surface of the flange portion 21F of the first cylinder 21.
Further, a lower portion of the first piston 25 is guided by a guide ring 33 . The guide ring 33 is
It is fitted onto the inner peripheral surface of a ring member 31 fixed to the lower surface of the first cylinder 21 with a plurality of bolts 29 . The lower surface of the ring member 31 is provided on substantially the same plane as the lower surface of the slide 9.

The first fluid pressure chamber 35 communicates with a port 21P bored in the first cylinder 21.
P is connected to a joint 37 which is fixed through the slide 9.

Therefore, by supplying the working fluid from the port 21P to the first fluid pressure chamber 35, the first piston 25 is always urged downward. The first piston 25 is supported by the ring member 31 in the lower position. By adjusting the pressure of the working fluid, the downward urging force of the first piston 25 can be freely adjusted.

A cylinder cap 39 and a substantially cylindrical cylinder housing 41 are fitted and fixed in the small diameter recess 9B of the slide 9 with a plurality of bolts 43. A lower portion of the cylinder housing 41 passes through the inside of the first piston 25, and its lower surface is provided on substantially the same plane as the lower surface of the slide 9. Further, a second cylinder 45 is fitted into the cylinder housing 41. This second cylinder 4
A second piston 47 is fitted into the inside of the piston 5 so as to be vertically movable.

The second cylinder 45 and the second piston 47
constitutes a second fluid pressure device in the upper cushion device 19 together with the second fluid pressure chamber 51. A piston rod 47R extending downward from the second piston 47 is guided by a guide bush 49 fitted into a guide hole 41G formed in the cylinder housing 41. The cylinder cap 39 has a port 3 connected to the second fluid pressure chamber 51.
9P is bored, and a joint 39J is connected and fixed to this port 39P.

Therefore, by supplying the working fluid from the port 39P to the second fluid pressure chamber 51, the second piston 47 is always urged downward. The second piston 47 is supported by the cylinder housing 41 in the lower position. By adjusting the pressure of the working fluid, the downward urging force of the second piston 47 can be freely adjusted.

Next, the lower cushion device 53 shown in FIG.
The details will be explained below.

A lower cushion device 53 is attached to the lower surface of the bed 5 of the press machine 1. The lower cushion device 53 is supported by a base plate 57 that is integrally supported by the lower ends of a plurality of columns 55 vertically provided on the lower surface of the bed 5.

A bellows 59 is provided on the upper surface of the base plate 57.
A cushion plate 61 is attached to the upper part of the bellows 59. The bellows 59 and the like constitute a first fluid pressure device in the lower cushion device 53. Compressed air is constantly supplied into the bellows 59 from a port 57P formed in the base plate 57.

Therefore, the bellows 59 is always in a state of expanding, and the cushion plate 61 is always urged upward. The pressure within the bellows 59 can be adjusted freely, and the upward biasing force of the cushion plate 61 can be adjusted freely.

A cylindrical part holder 63 is fixed to the upper part of the cushion plate 61 with a plurality of bolts 65. The upper part of the pad holder 63 faces relatively large holes 5H and 7H formed in the bed 5 and the bolster 7, respectively.
An annular outer pad 67 is integrally attached to the upper part of this pad holder 63 with bolts 69. A lid member 71 is detachably attached to the inner peripheral surface of the outer pad 67.

A third cylinder 73 is further integrally fixed to the upper surface of the base plate 57. A cylinder cap 75 of a third cylinder 73 is integrally attached to the lower surface of the base plate 57 with bolts or the like. The third cylinder 73 is located within the bellows 59, and a third piston 77 is fitted into the third cylinder 73 so as to be vertically movable.

The third cylinder 73, the third piston 77, etc. constitute a second fluid pressure device in the lower cushion device 53. Port 7 bored in the cylinder cap 75 into the third fluid pressure chamber 79
Working fluid is supplied from 5P, and the third piston 77 is always urged upward. Said third
The pressure within the fluid pressure chamber 79 is adjustable.
The upward biasing force of the piston 77 can be freely adjusted.

A piston rod 77R extending upward from the third piston 77 passes through the third cylinder 73 and the cushion plate 61 in a slidable manner. A connecting rod 81 that slidably passes through the part holder 63 is integrally connected to the upper end of the third piston by a plurality of bolts 83. The upper end of the connecting rod 81 faces near the top of the pad holder 63, and a disc-shaped inner pad 85 is integrally attached to the upper end.

As can be understood from the above structure, the outer pad 67 and the inner pad 85 of the lower cushion device 53 are always urged upward, and are lowered by appropriately applying an external force from above.

Next, with reference to FIG. 4, the structure of an air-hydraulic conversion circuit that applies pressure to each fluid pressure device in the upper cushion device 19 and the lower cushion device 53 will be explained. First, the upper cushion device 1
The hydraulic pressure adjustment of the second fluid pressure chamber 51 of No. 9 will be explained, and then the method of supplying oil to the first fluid pressure chamber 35 of the upper cushion device and the third fluid pressure chamber 79 of the lower cushion device will be explained.

Filter F is installed on the air line 87a in the factory.
The first air pipe AL1 connected through the
A pressure reducing valve RV1 and a first solenoid valve SOL1 are connected in sequence.

The first solenoid valve SOL1 has a first chamber 91a of a booster 91 equipped with a pressure increasing piston 89.
The second air pipe AL2 connected to the supply tank 9
3 is connected to the third air pipe AL3.
The supply tank 93 is the pressure increasing chamber 91 of the booster 91.
It is connected to b.

A fourth air pipe AL4 branched from the first air pipe AL1 is equipped with a second pressure reducing valve RV equipped with a pilot.
2. Second solenoid valves SOL2 are sequentially arranged. The second solenoid valve SOL2 is connected to the second chamber 91c of the booster 91. The pressure increasing chamber 91b of the booster 91 is connected to the second fluid pressure chamber 51 of the upper cushion device 19 via a first oil passage OL1 provided with a first check valve CV1. A flow control valve is provided in the second oil passage OL2 connected in parallel with the first check valve CV1.
FCV and third solenoid valve SOL3 are connected in sequence.

In the above configuration, under normal conditions, the air source 8
7a is constantly acting on the supply tank 93 via the first solenoid valve SOL1, so that the oil in the supply tank 93 flows into the single pressure chamber 91 of the booster 91.
b. When the first, second, and third solenoid valves SOL1, SOL2, and SOL3 are excited, the booster 91 is activated and the pressure increase chamber 91b
The oil inside is supplied to the second fluid pressure chamber 51 of the upper cushion device 19.

When the pressure in the second fluid pressure chamber 51 increases due to the rise of the second piston 47, this pressure is transferred to the pressure increasing chamber 9 of the booster 91 via the first check valve CV1.
1b. Pressure increase chamber 91b of booster 91
A flow control valve FCV is connected to the second fluid pressure chamber 51 from the third fluid pressure chamber 51.
Knockout can also be performed by lowering the second piston 47 by sending oil through the solenoid valve SOL3.

Next, the first fluid pressure chamber 3 of the upper cushion device 19
5 and the third fluid pressure chamber 7 of the lower cushion device 53
The method of supplying oil to the tank 9 will be explained.

5th air pipe AL connected to oil tank 95
5, filter F2 from the air source 87b side;
Third pressure reducing valve RV3, second check valve CV
2. 4th solenoid valve SOL4 and safety valve
SVs are connected sequentially.

Therefore, the fourth solenoid valve SOL
4, air pressure is applied to the oil tank 95.

This air pressure is adjusted by the third pressure reducing valve RV3.

A fifth solenoid valve SOL5 with four ports and three positions is connected to the oil tank 95 via a third passage OL3. This fifth solenoid valve
SOL5 is connected to the first oil passage of the upper cushion device 19 via a fourth oil passage OL4 equipped with a check valve CV3.
It is connected to a fluid pressure chamber 35. Furthermore, the fifth solenoid valve SOL5 is connected to the third fluid pressure chamber 79 of the lower cushion device 53 via a fifth oil passage OL5 in which a check valve CV4 is disposed.

Therefore, the oil in the oil tank 95 can be supplied to the first fluid pressure chamber 35 and the third fluid pressure chamber 79 by appropriately switching the fifth solenoid valve SOL5.

The fourth oil path OL4 includes the oil tank 9.
A drain oil passage OL6 connected to the drain oil passage OL6 is connected to the drain oil passage OL6. A pressure control relief valve RFV1 and a check valve CV5 are sequentially arranged in the drain oil passage OL6. The relief valve RFV1 is connected to the oil passage OL.
The pressure increase limit within the cylinder 4 can be adjusted arbitrarily, and is set by pneumatic pressure using the control cylinder CY1.

As the second piston 47 rises, the first fluid pressure chamber 3
As the pressure of 5 gradually increases, oil can be returned to the oil tank 95 through the relief valve RFV1 at a predetermined pressure. Also, relief valve RFV1
When the sixth solenoid valve SOL6 connected to the pilot oil passage OL8 is made conductive,
The pressure within the fourth oil passage OL4 can be rapidly reduced. The control cylinder CY1 is connected to a sixth air pipe AL6 via a fourth pressure reducing valve RV4.

Although the hydraulic pressure adjustment of the first fluid pressure chamber 35 of the upper cushion device 19 has been described, the same applies to the third fluid pressure chamber 79 of the lower cushion device 53. Code RFV1 becomes RFV2, CY1 becomes
CY2 and RV4 correspond to RV5, respectively.

A case will be described in which, for example, a product 97 as shown in FIG. 5 is molded using the above-mentioned upper cushion device 19 and lower cushion device 53. The product 97 illustrated in FIG.
It has a cylindrical shape with a hole 97b formed in the center of the ceiling 97a. Also hole 97b
An annular groove 97c is formed on the outside of the annular groove 97c, and a projection 97d is formed on the outside of the annular groove 97c. moreover,
Recesses 97e are formed at three locations on the outer periphery of the product 97, and a hole 97f is formed at the bottom of each recess 97e.

Products that can be formed using a press machine equipped with a double-layered cushioning device are bowler hat-shaped (silk hat-shaped).
In addition to the above-mentioned examples, there are other products such as tip-shaped products with flanges, various stepped products, and products with punched holes. This is just one example of the products illustrated here, and is not intended to limit the target products.

The mold for manufacturing the product 97 as described above will first be described.It has a configuration as shown in FIG. 6. An example of a mold unit (die set) is shown.

Referring to FIG. 6, a board 101 is fixed on a machine stand 99 fixed to the upper surface of the bolster 7. A plurality of pillars (posts) 103 are erected on the substrate 101, and an upper plate 105 is guided by the pillars 103 so as to be vertically movable. A lower mold 107 for molding the product 97 is mounted on the substrate 101, and a lower mold 107 is mounted on the lower surface of the upper plate 105.
An upper die 109 corresponding to the above is attached.

The configuration of the lower mold 107 will be explained. At the center of the plate 111 fixed to the upper surface of the substrate 101, a male die 113 whose upper side substantially matches the inner shape of the product 97 is fixed and erected. A die hole 115 corresponding to the hole 97b of the product 97 is formed in the center of the male mold 113, and a pin 117 for forming the product protrusion 97d is embedded at an appropriate position on the upper surface. Furthermore, a recess 1 corresponding to the recess 97e of the product 97 is provided on the outer peripheral surface of the male die 113.
19 is formed in three places, and a groove 97c is formed on the top surface.
An annular recess 121 corresponding to the groove 121 is formed.

A first annular body 123 is fitted into the lower part of the male mold 113 so as to be movable up and down, and the first annular body 123 has a shape that faces into each recess 119 corresponding to the recess 97e of the product 97. Three protrusions 125 are formed. On the upper surface of this protrusion 125, the product 9
A die hole 127 corresponding to the hole 97f of No. 7 is formed. The first annular body 123 includes the substrate 10
The lower end of the first lifting rod 129 is supported by a disc-shaped first lifting pad 131.

The first lifting pad 131 passes through the bolster 7 and the bed 5 and connects to the lower cushion device 53.
The first cushion pin 133 is supported on the inner pad 85 in the first cushion pin 133. Therefore, the first annular body 123 is always urged upward, and under normal conditions, the upper surface of the protruding portion 125 substantially coincides with the upper surface of the male die 113.

A cylindrical second annular body 135 is fitted on the outside of the first annular body 123 so as to be vertically movable.
An outward flange portion 135F is formed on the lower side of the second annular body 135. This second annular body 135
is supported by a second lifting rod 137 similar to the first lifting rod 129, and this second lifting rod 13
7 is supported by a second annular lifting pad 139.

The second elevating pad 139 is supported by a second cushion pin 141, and the second cushion pin 141 is supported by the outer pad 67 of the lower cushion device 53. Therefore, the second annular body 135 is always urged upward, and under normal conditions, its upper surface substantially coincides with the upper surface of the male mold 113.

A cylindrical third annular body 143 is fitted on the outside of the second annular body 135 so as to be vertically movable. On the upper part of this third annular body 143, a second annular body 13 is provided.
Flange portion 1 corresponding to flange portion 135F of No. 5
43F is formed on the inside, and product 97 is formed on the top surface.
Groove 1 for placing and positioning the workpiece for manufacturing
43G is formed.

The third annular body 143 is normally lifted up by the second annular body 135, and its upper surface substantially coincides with the upper surface of the male die 113. On the outside of this third annular body 143, there is an annular guide body 14 fixed to the plate 111.
5 is fitted.

The upper plate 105 is integrally attached to the lower surface of the slide 9 in the press machine. This top plate 1
A disk-shaped punch holder 151 is attached to the center of the lower surface of the lower die 107 and supports a punch 147 corresponding to the die hole 115 in the lower die 107 and a punch 149 corresponding to the die hole 127 in a hanging manner.

At the center of the lower surface of the punch holder 151, a female mold 153 having an inverted T-shaped cross section and whose lower surface has a shape corresponding to the shape of the upper surface of the male mold 113 is arranged so as to be vertically movable. This female mold 153 is integrally connected to the lower end of a third lifting rod 155 that passes through the upper plate 105 so as to be vertically movable. The upper end of this lifting rod 155 is connected to a relay pin 157. The upper end of the relay pin 157 can freely come into contact with the lower end of the piston rod 47R of the second piston 47 in the upper cushion device 19.

An annular elevating body 159 is provided on the outside of the female mold 153.
is arranged to be able to move up and down, and this elevating body 159
There are recesses 97 in the product 97 at three locations on the bottom surface of the product 97.
A protruding portion 161 for forming e is provided vertically. The punch 149 is inserted into these protrusions 161.
is located. The elevating body 159 has the upper plate 1
A plurality of bolts 163 pass through 05 in a vertically movable manner.
and is integrally connected and supported to the lower end of the fourth lifting rod 165. Said fourth lifting rod 165
The upper end portion can freely come into contact with the lower surface of the first piston 25 in the upper cushion device 19 .

A stepped cylindrical drawing die 167 disposed on the outside of the punch holder 151 and the elevating body 159 is connected to the upper plate 1.
It is fixed to the bottom surface of 05. The inner diameter of the lower end of this drawing die 167 is formed to be slightly larger than the diameter of the male die 113, and the outer diameter is approximately equal to the outer diameter of the second annular body 135. It faces the upper end of the annular body 135.

An annular plate holder 16 is provided on the outside of the drawing die 167.
9 are arranged so as to be movable up and down. This plate presser 16
9 is integrally supported by the lower end portions of a plurality of bolts 171 that pass through the upper plate 105 in a vertically movable manner. The plate holder 169 is always pressed downward by an elastic device 173 such as a coil spring mounted between the plate holder 169 and the upper plate 105.

In the above configuration, a processing situation after a disk-shaped plate material (workpiece) is placed and positioned on the lower die 107 will be described.

When the slide 9 in the press machine 1 is lowered, the upper plate 105 is lowered, and first, the plate holder 169 of the upper die 109 presses the plate material between it and the third annular body 143 of the lower die 107. When the upper plate 105 is further lowered, the female mold 15
3 presses the plate material between it and the upper surface of the male die 113 to form the upper surface of the product 97. At this time, slide 9,
By lowering the upper plate 105, the third lifting rod 15
5. The relay pin 157 and the second piston 47 will rise relatively.

Therefore, when the pressure in the second fluid pressure chamber 51 in the upper cushion device 19 gradually increases and becomes higher than the pressure in the pressure intensification chamber 91b in the booster 91, the pressure intensification piston 8 in the booster 91 increases.
9 to the left in FIG. 4 to return oil to the supply tank 93.

After the female mold 153 press-forms the plate material as described above, when the slide 9 and the upper plate 105 further descend, the protruding part 161 of the elevating body 159 faces the protruding part 125 of the first annular body 123, and the plate material is pressed. to hold. At this time, the pressure in the first fluid pressure chamber 35 in the upper cushion device 19 and the pressure in the third fluid pressure chamber 79 in the lower cushion device 53 gradually increase. However, if the set pressure in relief valve RFV1 is changed to
By setting the pressure higher than the set pressure in advance, the first annular body 123 is gradually lowered.

Therefore, the concave portion 97e in the product 97 can be drawn without causing wrinkles.
Further, when the first annular body 123 in the lower mold 107 is gradually lowered and comes into contact with the plate 111 and stops lowering, the sixth and seventh solenoid valves SOL6 and SOL7 are brought into communication. Then, the first fluid pressure chamber 35 and the third fluid pressure chamber 79
Since the internal pressure is extremely reduced, the force required to lower the slide 9 can be reduced. The operation of the solenoid valves SOL6 and SOL7 can be controlled by an appropriate sequence circuit.

As mentioned above, the second annular body 135 of the lower die 107
The drawing die 169 of the upper die 109 descends while holding the plate material, and the plate material is trimmed and the outer periphery of the product 97 is drawn without wrinkles. And almost at the same time, upper mold 10
Separation 97 by punches 147, 149 in 9
Holes 97b and 97f are punched out. After that, the slide 9 passes through the bottom dead center and then rises.

As the slide 9 rises, the upper plate 105 also rises. At this time, the molded product fits into the drawing die 167 and rises as one.

If the third solenoid valve SOL3 is energized and communicated when the slide 9 has risen to near the top dead center, the high pressure in the booster 91 is supplied to the second fluid pressure chamber 51, so that the female Type 15
3 will stick out, and the product will stick out (knock out).

FIG. 7 shows another embodiment in which the air-hydraulic conversion circuit shown in FIG. 4 is further improved. Components designated by the same reference numerals as in FIG. 4 have the same functions as those described in FIG. Moreover, the four points A ₁ , A ₂ , A ₃ , and _A all indicate the same points as in FIG. 4.

Examples of this improved air-hydraulic conversion circuit will be explained in four parts.

The first pneumohydraulic circuit improvement relates to knockout.

The improved circuit diagram is shown in Figure 7. booster 2
17 pressure increasing piston 86 is a solenoid valve 20
It is pressed by the air pressure sent from the air reservoir T via 9. The opening and closing operations of the solenoid valve 209 are performed by the solenoid valve 201 through a pilot path. The pressure in the supply tank 211 is maintained at a constant pressure by opening and closing the solenoid valve 203.

The opening and closing operations of the check valves 213 and 215 with pilots are performed by solenoid valves 205 and 2, respectively.
This is done by exciting 07. The oil pressurized by the booster 217 passes through the check valve 215 with pilot and the check valve 223 to the second check valve 223.
It is guided to the fluid pressure chamber 51.

The check valve 215 with pilot can normally return the oil in the second fluid pressure chamber 51 to the booster 217 side. When the solenoid valve 207 issues a signal via the pilot path, oil can be supplied from the booster 217 side toward the second fluid pressure chamber 51. A fluid control valve 227 is connected in parallel with the check valve 223.

The operating status of this air-hydraulic conversion circuit will be explained.

By the time the upper mold 109 starts machining, the second
The fluid pressure chamber 51 is the hydraulic chamber 217b of the booster 217.
Assume that the same pressure as the pressure is satisfied.
When the upper mold 109 descends and begins to hold down the workpiece, the pressure in the second fluid pressure chamber 51 increases, but at this time both the piloted check valves 213 and 215 function in the same way as a normal check valve.

Therefore, the pressure in the second fluid pressure chamber 51 is lower than that of the booster 21.
This is the same as the pressure in the pressure increasing chamber 217b of No.7. When the drawing process is completed, the pressure in the second fluid pressure chamber 51 is supplied to the supply tank 211 in order to lighten the movement of the slide 9.
It can also be as low as the pressure. In this case, the pilot check valve 213 may be opened using the solenoid valve 205.

Next, when the slide 9 of the press machine starts to rise, the oil is expelled and the second piston 47 is in the upper position. Since the check valve with pilot has not yet been opened, oil does not come from booster 217. When the check valve 215 with a pilot is opened at a position where the slide 9 has risen to a certain extent, oil is introduced into the second fluid pressure chamber 51 from the booster 217, knocking out the finished product. Then the second
The pressure in the fluid pressure chamber increases to the initial pressure.

Therefore, the knockout process can be performed more smoothly.

A second air-hydraulic conversion circuit improvement relates to a booster.

The booster 217 in FIG. 7 has a hydraulic piston 89.
A dog 225 is provided. Corresponding to this dog 225, limit switch 219 is placed at the highest oil level position.
A limit switch 221 is installed at the lowest oil level position.

When the limit switch 221 senses the minimum oil level, the solenoid valve 205 sends a pilot signal to the pilot check valve 213.
Then, oil can be supplied from the supply tank 211 to the pressure increasing chamber 217b through the check valve 213 with pilot. Of course, both limit switches 219 and 221 are positioned so that they do not interfere with each other during the normal press stroke process.

Therefore, the booster 217 is extremely convenient because the oil amount adjustment is automated.

A third air-hydraulic conversion circuit improvement relates to applying initial pressure to the cushioning device.

The oil at a constant pressure from the tank 95 is passed through the filter 30.
5. There is a first circuit No. 1 that supplies the first fluid pressure chamber 35 via the check valve 309. There is a second circuit No. 2 that maintains pressurized oil from the first fluid pressure chamber 35 at a predetermined pressure based on machining.

The second circuit has a relief valve RFV shown in Figure 4.
There is a relief valve 311 similar to 1. The most important point is that in addition to these two circuits, a third circuit equipped with a relatively small and small-capacity oil pump P is provided in parallel with the first circuit. Furthermore, the third circuit No. 3 is also the same as the first circuit No. 3.
Like circuit No. 1, a check valve 303 is provided. Further, a safety valve 307 is provided to circulate oil having a predetermined pressure or higher so that the pressure does not rise above a predetermined pressure.

The operation of this oil pump P will be explained.

The drawing process is started, and the first piston 25 moves up. Next, when the drawing process is completed, oil at a constant pressure in the oil tank 95 flows from the first circuit via the check valve 309. The pressure in the first fluid pressure chamber 35 at this time is the same as the pressure in the oil tank. Therefore, at this point, the pressure is increased to near a predetermined pressure by the pump P.

A large amount of oil has been injected from the first circuit No. 1 and the first
Since the fluid pressure chamber 35 is filled with oil, even a relatively small pump can quickly raise the pressure to a predetermined level. The pressure setting value of the complete valve 307 may be adjusted to a value slightly lower than the pressure of the relief valve 311.

Therefore, the pressure in the first fluid pressure chamber 35 can be increased to a predetermined pressure before the next processing starts, so that the product can be finished better.
Incidentally, since the pump P may be relatively small and have a small capacity, it is not only inexpensive to set up, but also has the effect of saving energy. The third part of the lower cushion device 53
The same applies to the fluid pressure chamber 79.

The fourth improvement of the air-hydraulic conversion circuit will be explained. The fourth improvement will be explained with reference to FIG.

A relief valve 311 is provided to suppress the pressure that is gradually increased based on the machining operation of the cushion device to within a predetermined pressure. A pressure regulating tank 319 that is adjusted by air pressure is provided. This pressure regulating tank 3
An adjusting device 313 is provided which adjusts the pressure of the relief valve 311 with a hydraulic pressure of 19. The adjustment device 313 has, for example, a small hydraulic piston inside, and is configured to press an adjustment spring of a relief valve with this piston.

In this way, if the pressure is adjusted by hydraulic pressure via the pressure regulating tank 319, it is possible to have both the advantage of air piping, which allows remote control, and the advantage of hydraulic pressure, which allows precise adjustment. In addition, check valve 317 with pilot is replaced with solenoid valve 4.
13, the adjustment pressure of the relief valve 311 can be lowered as desired.

Therefore, the pressure in the first fluid pressure chamber 35 can be maintained at a stable pressure.

The same applies to the third fluid pressure chamber 79 of the lower cushion device 53. The pressure regulating tank 411 corresponds to the pressure regulating tank 319, and the regulating device 405 corresponds to the regulating device 313.

As can be understood from the above description of the embodiments, according to the present invention, even products with complex shapes that require multi-stage molding can be molded within one stroke of the slide in a press machine. It is something. Since the pressure sources for the upper and lower cushion devices are based on pneumatic-hydraulic conversion mechanisms, the structure can be made compact and can be manufactured at extremely low cost. Furthermore, since the oil pressure in each cushion device can be set freely, it can be set to the optimum condition depending on the material of the plate (work), etc.

Furthermore, since the initial pressure during processing is made appropriate, the finishing accuracy of the processed product can be improved.

Furthermore, since the relief valve is provided to maintain the pressure, which is gradually increased based on the processing operation, at an accurate predetermined pressure, the accuracy of the processed product can be improved.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention. FIG. 1 is a front view showing an example of a press machine in which the present invention can be practiced. FIG. 2 shows an enlarged sectional view of the upper cushion device of the press machine shown in FIG. In addition, in FIG. 2, different states are shown on the left and right with the center line as a border. FIG. 3 shows an enlarged sectional view of the front lower cushion device. Note that the bellows portion is shown with a portion cut away. FIG. 4 is a diagram showing hydraulic circuits of the upper cushion device and the lower cushion device, and a pneumatic-hydraulic conversion circuit for adjusting and controlling the hydraulic circuits using pneumatic pressure. FIG. 5 is a perspective view showing an example of a product processed by the press machine.
FIG. 6 is a sectional view of a mold for molding the product shown in FIG. FIG. 7 is a circuit diagram showing another embodiment of the air-hydraulic conversion circuit shown in FIG. 4. 3...Frame, 5...Bed, 9...Slide, 19...Upper cushion device, 53...Lower cushion device.

Claims (1)

[Scope of Claims] 1. A slide 9 is installed in a position above the bed 5 fixed to the frame 3 of the press machine 1 so as to be movable up and down, and on the underside of the bed 5, at least the first and second fluids in the lower part are provided. A press machine is provided with a lower cushion device 53 equipped with a pressure device, and an upper cushion device 19 equipped with at least first and second upper fluid pressure devices is attached to the slide 9. , each cushion device 1
The pressure sources 9 and 53 are constituted by an air-hydraulic conversion mechanism that converts air pressure into oil pressure, and the lower cushion device 53 and the upper cushion device 19
The hydraulic circuit of the cushion device is provided with a first circuit No. 1 that supplies a constant pressure oil to the cushion device in a one-way manner, and a first circuit No. 1 that supplies a certain pressure oil to the cushion device in a one-way manner. A second valve equipped with a relief valve 311 that suppresses the pressure that is gradually increased based on the operation to within a predetermined pressure.
A press machine equipped with a cushioning device, characterized in that it consists of a circuit No. 2 and a third circuit No. 3 in which a pressure pump P is provided in parallel with the first circuit No. 1. 2. A slide 9 is installed in a position above the bed 5 fixed to the frame 3 of the press machine 1 so as to be movable up and down, and the lower surface of the bed 5 is provided with at least first and second fluid pressure devices in the lower part. A press machine is provided with a lower cushion device 53 mounted thereon, and an upper cushion device 19 comprising at least first and second upper fluid pressure devices is mounted on the slide 9.
The pressure sources 9 and 53 are constituted by an air-hydraulic conversion mechanism that converts air pressure into hydraulic pressure, and the lower cushion device 53 and the upper cushion device 19
The pressure regulating tank is provided with a relief valve 311 that can individually adjust the pressure of each hydraulic mechanism in the cylinder, and is provided with a relief valve 311 that suppresses the pressure that gradually increases based on the processing operation of the cushioning device to within a predetermined pressure, and the pressure is adjusted by air pressure. The relief valve 31 with a hydraulic pressure of 319
1. A press machine equipped with a cushion device, characterized in that it is provided with an adjustment means for adjusting the pressure.