JP2579369Y2 - Hydraulic equipment for press machines - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic device for a press machine which minimizes an oil hammer generated in an oil return line.

[0002]

2. Description of the Related Art Conventionally, in a hydraulic device, when oil flows at a high speed in a return pipe, a phenomenon called an oil hammer occurs due to collision between oil and oil. As a means for mitigating the oil hammer, a commercially available accumulator or the like is incorporated in the oil return circuit to mitigate the impact of oil collision, thereby mitigating the oil hammer.

[0003]

By the way, in the above-mentioned conventional hydraulic device, an oil hammer can be prevented to a certain extent with a high-speed flow of oil. If hits progress and a large amount of oil flows in the return line, there is a limit in the current condition.

[0004]

SUMMARY OF THE INVENTION As described above, in order to solve the conventional problems, the present invention relates to a hydraulic machine for a press machine having a drive cylinder for raising and lowering a ram of the press machine. A tank-type accumulator and a cylinder-type accumulator are sequentially arranged from the drive cylinder side in the middle of the return line connecting the cylinder and the tank, and the cylinder-type accumulator includes an outer cylinder communicating with the return line, And a resilient device provided in the outer cylinder and biasing the piston toward the return circuit.

[0005]

With the above arrangement, when the drive cylinder is operated to raise and lower (particularly ascend) the ram, return oil discharged from the drive cylinder is sent to the tank through the return pipe. Here, first, the return oil flows into the tank type accumulator, and the return oil in the return line is reduced in pressure and speed.
Further, the return oil of low pressure and low speed flows into the outer cylinder of the cylinder type accumulator, and moves the piston to the opposite side of the return line while resisting the urging force of the elastic machine. The return oil is further reduced in pressure and speed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. In addition, there is a press machine as a machine employing the hydraulic device of the present invention, but in this embodiment, a turret punch press will be described as a target machine.

Referring to FIG. 4, since the turret punch press 1 has a known structure, a detailed description thereof will be omitted and only a brief description will be given.

The turret punch press 1 is composed of a portal frame in which an upper frame 9 is supported by side frames 5 and 7 erected on both sides of a base 3. On the lower surface of the upper frame 9, a disk-shaped upper turret 13 on which a number of upper dies 11 are mounted is rotatably mounted on an upper rotating shaft 15. On the upper surface of the base 3, a lower turret 19 to which a number of lower dies 17 opposed to the respective upper dies 11 are mounted is rotatably mounted by a lower rotation shaft 21. Further, the upper mold 11 is placed in the upper frame 9.
Ram 25 actuated by the drive cylinder 23 at a position just above
Is provided.

With the above configuration, although not shown, the upper turret 13 and the lower turret 19 rotate in the same direction in synchronization with the servo motor, and the upper and lower dies 11, 17 selected immediately below the ram 25 are moved. Indexing, drive cylinder 2
3 moves the ram 25 up and down to move the upper mold 11
And the lower mold 17 cooperate to perform punching on the work W.

On the other hand, a movement positioning device 27 is provided for moving and positioning the work W in the front-rear and left-right directions. That is, the carriage base 29 of the movement positioning device 27 is integrally attached to the movable table 31, and is movable in the front-rear direction. A carriage 35 having a clamp device 33 for gripping the plate material W is provided on the carriage base 29 so as to be movable in the left-right direction. Note that a fixed table 36 for movably supporting the plate material W is provided on the upper surface of the base 3.

With the above configuration, the plate material W on the fixed table 36 and the movable table 31 is gripped by the clamp device 33. By moving the carriage base 29 in the front-rear direction and the carriage 35 in the left-right direction, the plate material W can be moved and positioned at a predetermined position in the front-rear, left-right direction.

The hydraulic device 37 for operating the turret punch press 1 configured as described above is constituted by a hydraulic circuit 39 shown in FIG. Since the hydraulic circuit 39 is a partially improved circuit having a known configuration, the newly added components will be mainly described, and detailed description of known members will be omitted.

The configuration of the hydraulic circuit 39 is such that the hydraulic pump 41 is driven to suck oil from the tank 43, and the pressure oil passes through the pipe 47 via the filter 45. This line 47 is connected to the drive cylinder 23.
Is connected to the P port of the electrohydraulic servo valve 51 provided in the manifold 49. A plurality of accumulators 59 selected by a pressure gauge 53, a pressure control valve 55, and an electromagnetic switching valve 57 are provided in the middle of the pipe line 47.

A cylinder-type accumulator 63 and a tank-type accumulator 65, which are main parts of the present embodiment, are provided in parallel in a return line 61 connected to the T port of the hydraulic servo valve 51. Pipe 61 is tank 4
3 is connected.

Referring to FIG. 3, the cylinder type accumulator 63 is of a cylinder type, in which a piston 69 is movably provided in an outer cylinder 67, and the piston 69 and the outer cylinder 6 are provided.
7 is attached to the bottom plate 71 of the
The piston 69 is constantly urged upward by the elastic force of 3. An outflow / inflow pipe 77 through which return oil flows in / out is connected to the upper plate 75 of the outer cylinder 67.

With the above structure, the return oil entering the inflow / outflow pipe 77 is pushed down by the piston 69 to absorb the pressure, and is discharged from the inflow / outflow pipe 77 as the reduced pressure oil to return to the tank 43.

Referring to FIG. 2, the tank type accumulator 65 is formed in a tank shape by a body 79, a bottom plate 81 and an upper plate 83, and the upper plate 83 is provided with a return oil inflow / outflow pipe 85. The inside of the mold accumulator 65 contains a certain amount of oil.

The oil flowing out of the A port of the electrohydraulic servo valve 51 is connected to a P port of a two-position electromagnetic switching valve 87 capable of switching between a low-pressure high-speed valve H and a high-pressure low-speed valve R via a line 89. The oil passage 93 is connected from an A port on the outlet side of the two-position electromagnetic switching valve 87 to a small-diameter oil chamber 91 for lowering the ram 25 of the drive cylinder 23 at a high speed.

When the ram 25 of the drive cylinder 23 is lowered, the oil in the lower oil chamber 95 of the drive cylinder 23 is discharged from the pipe 9
7 and is returned to the tank 43 via the B port of the electrohydraulic servo valve 51. The oil passage 101 communicating with the large-diameter oil chamber 99 above the drive cylinder 23 is provided with a two-position electromagnetic switching valve 8.
7 is the position shown in FIG. 1, that is, when the low-pressure high-speed valve H is set, the electrohydraulic servo valve 5 passes through the pipe 103 from the B port to the T port of the two-position electromagnetic switching valve 87.
1 B port. In the middle of the pipe 103, there is provided a branch-stop type oil sump tank 105. The oil sump tank 105 is of a known configuration that is commercially available and has a predetermined amount inside the tank 105 in advance. Contains oil. Reference numeral 107 denotes a normally closed valve, and reference numeral 109 denotes PT.

With the above structure, when the ram 25 of the drive cylinder 23 is lowered, the electrohydraulic servo valve 51 is switched to the left (left in FIG. 1) valve.
The position switching valve 87 is switched to the low-pressure high-speed valve H. Then, the hydraulic pump 41 is driven to send the pressure oil to the P port of the electro-hydraulic servo valve 51 through the pipeline 47. Since the P port communicates with the A port, the pressure oil enters the P port of the two-position electromagnetic switching valve 87 through the pipe 89. This P port is A
The pressure oil flows into the small-diameter oil chamber 91 through the oil passage 93 of the drive cylinder 23 because it communicates with the port.

When the pressure oil enters the small-diameter oil chamber 91, the ram 25 descends at a high speed. However, since the large-diameter oil chamber 99 communicates with the oil sump tank 105 through the conduit 103, the large-diameter oil chamber 9
The interior of 9 is not vacuumed and oil is replenished from the oil reservoir tank 105.

When the ram 25 descends at a high speed and moves to a predetermined position, that is, when the lower surface of the ram 25 approaches the upper mold 11, the detection member (not shown) detects the signal and sends a signal to the two-position electromagnetic switching valve 87. And is switched to the high-pressure low-speed valve R side.
When the pressure is switched to the high-pressure low-speed valve R, the pressure oil is also supplied to the large-diameter oil chamber 99, so that the ram 25 descends at a high pressure and low speed, and the work is punched. The drive cylinder 23
In the lower oil chamber 95 passes through the pipe 97, returns from the B port of the electrohydraulic servo valve 51 to the tank 43 through the T port through the T port. At this time, the cylinder type accumulator 63 and the tank type The return oil is buffered by the accumulator 65, and the low pressure and low speed are returned to the tank 43.
Oil hammer does not occur.

When raising the ram 25 of the drive cylinder 23, the electrohydraulic servo valve 51 is switched to the right valve, and the two-position electromagnetic switching valve 87 is set to the high-pressure low-speed valve R. Then, the hydraulic pump 41 is driven to send the pressure oil to the P port of the electromagnetic hydraulic servo valve 51 through the pipeline 47. Since this P port communicates with the B port, the pressure oil passes through the line 97 and
The ram 25 moves up into the lower oil chamber 95 of FIG.

The oil in the large-diameter oil chamber 99 and the small-diameter oil chamber 91 at the upper part of the drive cylinder 23 passes from the A and B ports of the two-position electromagnetic switching valve 87 through the P port to the electrohydraulic servo valve 51 via the P port. Out of the tank 43 from the A port through the T port. At this time, the return oil is buffered by the cylinder type accumulator 63 and the tank type accumulator 65, and is returned to the tank 43 at low pressure and low speed.

Thus, the return oil when the ram 25 is lifted up has a large flow rate and a high speed and high pressure, and is returned to the tank 43. Therefore, an oil hammer is easily generated, but the tank type accumulator 65 is used.
In addition, the cylinder type accumulator 63 can prevent the generation of an oil hammer as much as possible even at a large flow rate due to a high hit.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

The configuration of the present invention is summarized as follows.

That is, in the turret punch press hydraulic device 37 having the drive cylinder 23 for raising and lowering the ram 25 in the turret punch press 1, the tank A mold accumulator 65 and a cylinder accumulator 63 are sequentially arranged from the drive cylinder 23 side. The cylinder accumulator 63 is provided movably in the outer cylinder 67 communicating with the return pipe 61. It is characterized by comprising a piston 69 and a bomb 73 provided in the outer cylinder 67 and capable of urging the piston 69 toward the return line 61 (upward in FIG. 3).

The operation of this embodiment is summarized as follows.

When operating the drive cylinder 23 to move the ram 25 up and down (especially ascending), the return oil discharged from the drive cylinder 23 is sent to the tank 43 through the return line 61. Here, first, the return oil flows into the tank type accumulator 65, and the return oil in the return pipe line 61 is reduced in pressure and speed. Further, the low-pressure and low-speed return oil flows into the outer cylinder 67 of the cylinder type accumulator 63, and the piston 69 opposes the return pipe 61 while opposing the urging force of the elastic machine 73 (see FIG. 3). By moving to the lower side, the return oil in the return line 61 is further reduced in pressure and speed.

As described above, according to the invention of this embodiment,
The return oil discharged from the drive cylinder 23 is sequentially reduced in pressure and speed by the tank type accumulator 65 and the cylinder type accumulator 63. Therefore, even if a large amount of return oil flows through the return line 61 at a high speed, the return line The impact caused by the collision between oil and oil at 61 can be reduced, and the occurrence of an oil hammer can be prevented as much as possible.

[0032]

As described above, according to the first aspect of the present invention, the return oil discharged from the drive cylinder is sequentially reduced in pressure and speed by the tank type accumulator and the cylinder type accumulator. Even if a large amount of high-speed return oil flows, the impact caused by the collision between the oil and the oil in the return line can be reduced, and the occurrence of an oil hammer can be prevented as much as possible.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a hydraulic device that is a main part of the present invention.

FIG. 2 is a sectional view of a dead end type oil sump tank provided in the hydraulic circuit in FIG. 1;

FIG. 3 is a sectional view of a pulsation preventing cylinder provided in the hydraulic circuit in FIG. 1;

FIG. 4 is a front view of a turret punch press according to one embodiment of the present invention.

[Explanation of symbols]

 23 Drive cylinder 37 Hydraulic device 39 Hydraulic circuit 61 Return line 63 Cylinder type accumulator 65 Tank type accumulator

Claims (1)

(57) [Scope of request for utility model registration] 1. A hydraulic machine for a press machine having a drive cylinder for raising and lowering a ram of a press machine, wherein a tank type accumulator and a cylinder type accumulator are provided in a return pipe connecting the drive cylinder and a tank. The cylinder type accumulator is sequentially disposed from the side, the cylinder type accumulator includes an outer cylinder connected to the return pipe, a piston movably provided in the outer cylinder, and a piston provided in the outer cylinder and moving the piston to the return circuit side. A hydraulic device for a press machine, comprising: an energizing machine.