JPH04302702A - Control method and device for hydraulic cylinder and plate finishing machine - Google Patents

Abstract

PURPOSE:To save the output of a pump motor by using both oil with low pressure and large flow and oil with high pressure and small flow for a hydraulic cylinder when, for example, a turret punch press is used as a plate finishing machine to move a ram upward or downward. CONSTITUTION:A piston rod (ram) 21 is integrated with a piston 33 provided in a hydraulic cylinder 21. When the ram 21 is expanded or contracted, expansion and contraction of the ram 21 is controlled by, for example, a double pump comprising a low pressure and large flow pump 49A and a high pressure and small flow pump 49B.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for controlling a hydraulic cylinder, and a plate processing machine.

0002

2. Description of the Related Art Conventionally, as a ram driving method for a hydraulic press, such as a plate processing machine, there is a known method in which a pump and a tank are connected to a hydraulic cylinder equipped with a ram via a directional control valve. This ram driving method is simple, and by simply moving the ram up and down, the workpiece is pressed by the cooperation of the upper die and the lower die.

However, the above ram drive system merely moves the ram up and down, and does not control the ram. As a ram drive system that controls this ram, a pump and tank are connected to the hydraulic cylinder via a servo valve, and a position sensor that detects the position of the ram and a pressure sensor that detects the oil pressure in the hydraulic cylinder. A system equipped with this has been developed and is actually in use.

0004

[Problems to be Solved by the Invention] By the way, with the latter ram drive method described in the above-mentioned prior art, it is possible to perform not only punching but also forming and nibbling, and the processing noise at that time is also lower than that of mechanical presses. It has been significantly reduced. However, when moving a ram attached to a hydraulic cylinder up and down, a large flow rate and high pressure of hydraulic pressure is required over the entire stroke of the ram.

[0005] That is, since the ram must be lowered as quickly as possible until the upper die (punch) hits the workpiece, a large flow rate is required, as well as pressure for press working. Therefore, there is a problem in that the motor that drives the pump as a hydraulic source has to have a large output and a large size, and the pump itself has to be large as well.

In order to improve this problem, we analyzed the operation of the ram and found that the ram starts to descend and the upper mold (punch)
A large flow of oil is required until the tip of the piston hits the workpiece, but since the oil pressure only needs to move the piston down, a low pressure should be sufficient. Further, high pressure is required from the time the tip of the punch hits the workpiece to the time it is processed, for example, during punch punching, but since the ram stroke is short, a small flow rate should be sufficient.

[0007] In view of the above circumstances, an object of the present invention is to make it possible to switch between low pressure, large flow rate and high pressure, small flow rate, so that the output of the pump drive motor can be reduced and the pump itself can be made smaller. It is an object of the present invention to provide a method for controlling a hydraulic cylinder, a device therefor, and a plate processing machine that can sufficiently handle the situation.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides for the expansion and contraction of a piston rod that is integrated with a piston provided in a hydraulic cylinder. This is a method of controlling a hydraulic cylinder, characterized in that it is controlled by a hydraulic pump with two pressures and two flow rates.

[0009] It is desirable that the hydraulic pump be a dual pump for high pressure, small flow rate and low pressure, large flow rate, and that the hydraulic pump be provided with a high pressure, small flow rate pump and a low pressure, large flow rate pump, and be controllable in a switchable manner. .

The present invention also provides a hydraulic cylinder equipped with a piston rod integrated into the piston, a pressure sensor for detecting the pressure within the hydraulic cylinder, and a position sensor for detecting the position of the piston rod's expansion and contraction. , 2 for supplying and discharging oil to the hydraulic chamber in the hydraulic cylinder.
A hydraulic cylinder control device was constructed by including a pump for pressure and two flow rates, and a control device for controlling the pressure sensor, position sensor, and pump.

Furthermore, the present invention provides a plate processing machine that processes a plate into a workpiece by making an upper die and a lower die cooperate by vertical movement of a ram attached to a hydraulic cylinder, and the pressure in the hydraulic cylinder is reduced. a dual pump having a pressure sensor for detecting a pressure sensor, a position sensor for detecting the vertical movement position of the ram, and a high-pressure small flow rate pump and a low-pressure large flow rate pump for supplying to and discharging the hydraulic chamber in the hydraulic cylinder; A plate processing machine was constructed by including a switching valve that switches oil from the dual pump to the cylinder chamber of the hydraulic cylinder, and a control device that controls the pressure sensor, position sensor, and switching valve.

0012

[Operation] By adopting the hydraulic cylinder control method, its device, and plate processing machine of the present invention, when the piston rod integrated with the piston provided in the hydraulic cylinder is extended and retracted, the piston rod can be moved. By controlling the expansion/contraction movement using, for example, a dual pump of high pressure, small flow rate and low pressure, large flow rate, the output of the pump driving motor can be reduced, and the pump itself can be made smaller.

[0013] The control device for the hydraulic cylinder also includes a pressure sensor for detecting the pressure in the cylinder chamber of the hydraulic cylinder, a position sensor for detecting the position of the expansion and contraction movement of the piston rod, and a sensor for supplying and discharging oil to and from the cylinder chamber. By providing a dual pump, the expansion and contraction of the piston rod can be controlled by switching between high pressure, small flow rate, and low pressure, large flow rate.

Furthermore, by using the plate processing machine using the above-mentioned control device, the plate processing of the workpiece can be performed with low noise.

[0015]

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0016] As plate material processing machines, continuous punching presses,
There are turret punch presses, bending, shearing, etc., and in this embodiment, a turret punch press will be explained as an example.

Referring to FIG. 4, the turret punch hydraulic press 1 is constructed of a gate-shaped frame consisting of a lower frame 3 and an upper frame 7 integrally provided with a column 5 interposed therebetween. The lower frame 3 and the upper frame 7
are appropriately spaced apart vertically to provide a working area 9.

A punching section 11 is provided on the left side of this work area in FIG. 4 for performing punching, blanking, and other punching operations on the workpiece. This punching part 11 includes a disk-shaped upper turret 13 and a lower frame 3 rotatably mounted on the upper frame 7.
It is composed of a disc-shaped lower turret 15 rotatably mounted on the turret. The upper turret 13 and the lower turret 15 are synchronously rotated in the same direction by a turret drive mechanism (not shown) and stopped at a predetermined position.

A plurality of punches 17 as upper molds are mounted on the circumference of the upper turret 13 at appropriate intervals, and the punches 17 are mounted on the circumference of the lower turret 15.
A plurality of dies 19 as lower molds are installed at positions facing the dies 7 .

A hydraulic cylinder 23 is provided within the upper frame 7 for vertically moving a ram 21 for striking the punch 17 at the processing position.

With the above configuration, the upper and lower turrets 13
, 15 are rotated to index the punch 17 and die 19 selected from the plurality of punches 17 and dies 19 to the processing position, and then the workpiece W is positioned on the die 19. Next, when the hydraulic cylinder 23 is actuated, the ram 21 moves up and down, and the punch 17 and die 19 cooperate to punch the workpiece W.

A moving positioning device 25 is provided on the right side of the working area 9 in FIG. The movable positioning device 25 includes a carriage base 27 that is guided by a guide member attached to the lower frame 3 and is movable in the Y-axis direction (horizontal direction in FIG. 4), and a carriage base 27 that is movable in the X-axis direction ( A carriage 29 that is movable in a direction perpendicular to the plane of the paper in FIG.
A plurality of clamps 31 are attached to 9 and can freely grip the workpiece W.
It consists of etc.

With the above configuration, the workpiece W held by the clamp 31 is moved in the X-axis and Y-axis directions, and the desired position of the workpiece W to be processed is positioned at the processing position of the punching section 11.

As shown in FIG. 1, the hydraulic cylinder 23 is equipped with a ram 21 as a piston rod integrated with a piston 33. This piston 33
There is an upper cylinder chamber 35 inside the hydraulic cylinder 23 bordering on
U and a lower cylinder chamber 35D are formed. Moreover,
A pressure sensor 37 is provided at the upper right end of the hydraulic cylinder 23 to detect the pressure inside the upper cylinder chamber 35U, and a pressure sensor 37 is provided on a part of the ram 21 to detect the position of the ram 21 when it moves up and down. A position sensor 41 having a position scale 39 is provided.

One end of a pipe 43 is connected to the upper cylinder chamber 35U, and the other end of the pipe 43 is connected to a two-port two-position switching valve 45 equipped with a solenoid valve SOL1.
is connected. P of this 2 port 2 position switching valve 45
One end of the piping 47 is connected to the port, and the other end of the piping 47 is connected to a low-pressure large-flow pump 49A of a swash plate type dual pump 49 consisting of a low-pressure large-flow pump 49A and a high-pressure small-flow pump 49B. . A check valve 51 and an accumulator 53 are provided in the middle of the pipe 47 in this order from the 2-port 2-position switching valve 45.

The dual pump 49 includes the dual pump 4
A drive motor 55 for operating the pump 9 is interlocked and connected to the dual pump 49, and a pipe 57 and a filter F are connected to the dual pump 49.
It is communicated with the tank 59 via. Said 2 ports 2
The T port of the position switching valve 45 is communicated with the tank 59 via a pipe 61.

One end of a pipe 63 is connected to the upper cylinder chamber 35U, and the other end of the pipe 63 is connected to a 4-port 3-position switching valve 6 equipped with solenoids SOL2 and SOL3.
It is connected to the A port of 5. Further, one end of a pipe 67 is connected to the lower cylinder chamber 35D, and
It is connected to the B port of the port 3-position switching valve 65.

One end of a pipe 69 is connected to the P port of the four-port three-position switching valve 65.
The other end is the high pressure low flow rate pump 49B of the dual pump 49.
It is connected to the. Furthermore, an accumulator 71 and a flow rate control valve 73 are provided in the middle of the pipe 67 from the 4-port 3-position switching valve 65 side, and the T port of the switching valve 65 is communicated with the tank 59 via the pipe. There is.

Ram 2 attached to the hydraulic cylinder 23
A control device 75 that controls the stroke in the vertical movement of 1
is shown in Figure 2. CP in this control device 75
For example, a CTC 79 for generating an internal clock, a general-purpose I/O interface 81, and an interface 83 for external communication control are connected to the U77.

Further, the CPU 77 is connected to A/D converters 85 and 87 for inputting signals from the position sensor 41 and the pressure sensor 37, and is also connected to an expansion bus connector 89. Further, connected to the CPU 77 are a ROM 91 in which machining programs and the like are stored, and a RAM 93 in which input values such as the material and plate thickness of the workpiece W are stored. Furthermore, the CPU 77 has an I/O device 9.
The switching valves 45 and 65 are connected via the amplifier 99, and the D/A converter 97 is also connected to the amplifier 99.
A flow rate control valve 73 is connected via.

With the above configuration, the control device 7 shown in FIG.
5 will be used to control the ram 21 attached to the hydraulic cylinder 23 to punch a workpiece W in cooperation with the punch 17 and die 19, with reference to FIGS. 1 and 3. When the drive motor 55 is driven to differentially operate the low-pressure large-flow pump 49A of the dual pump 49, the water is temporarily stored in the accumulator 53 via the piping 47, and when the accumulator 53 is operated, the check valve 51, 2 ports, 2 positions is switched. Upper cylinder chamber 35 of hydraulic cylinder 23 via valve 45
Low-pressure, large-flow oil is supplied to U, and the ram 21 descends, causing the tip of the punch 17 to hit the workpiece W due to this low-pressure, large-flow oil pressure.

When the tip of the punch 17 hits the workpiece W, the piston 33 stops descending. This is because the pressure is low and the reaction force from the workpiece W cannot be overcome. At this timing, the upper cylinder chamber 3
Since the pressure of 5U increases, it is detected by the pressure sensor 37. (In FIG. 3, the ram 21 has moved from the So position to the S1 position.) Based on the change in the signal from the pressure sensor 37, switching from the switching valve 45 to the switching valve 65 allows the high-pressure, low-flow rate pump of the dual pump to The oil is once sent to the accumulator 71 from the piping 69 through the flow rate control valve 73 from the oil 49B, and by further operating the accumulator 71, high-pressure, low-flow oil flows into the upper cylinder chamber 35U through the piping 63. Then, the ram 21 starts to further descend via the piston 33 as a result of high-pressure, low-flow oil flowing into the upper cylinder chamber 35U. This lowering speed is determined by the setting of the flow rate control valve 73. Work W
A small flow rate is sufficient since the stroke is only required for punching. (In Figure 3, from S1 to S2
Shows the status up to the time of moving to. ) Next, after punching is performed by the cooperation of the punch 17 and the die 19, the switching valve 65 is switched so that the punch returns to the tank 59 via the piping 63. At this time, the switching timing of the switching valve 65 can also be detected by the pressure sensor 37. When detected by the pressure sensor 37, a low pressure large flow rate flows into the upper cylinder chamber 35 from the low pressure large flow pump 49A through the piping 43, causing the piston 33 to descend. In other words, the punched materials are thrown away. (Figure 3
The position of S3 is shown in . ) After the punching material has been removed, the switching valve 45 is switched to the tank 59 side and the switching valve 65 is switched to the lower cylinder chamber 35D side, and oil flows from the high-pressure low-flow pump 49B through the piping 67 to the lower cylinder chamber 35D.
The piston 33 rises as the water flows into the air. The lower cylinder chamber 35D side can rise at a sufficiently high speed even with a small flow of oil due to the ratio of the cross-sectional areas of the piston 33 and the ram 21.

Furthermore, since the position of the downward movement of the ram 21 can be detected by the position sensor 41, the downward stop position of the ram 21 during molding can also be controlled with sufficient accuracy.

In the case of nibbling, the switching operation is between low pressure, large flow rate (downward) and high pressure, small flow rate (increase), but the rising speed is sufficiently high depending on the ratio of the cross-sectional areas of piston 33 and ram 21. It is possible. however,
The conditions at this time are that the punching force is less than or equal to the product of the low pressure and the area of the upper cylinder chamber 35U.

If high-speed, high-precision valves such as servo valves or electromagnetic proportional valves are used as the switching valves 45 and 65, the SPM can be made much faster. Furthermore, if a high-precision flow control valve such as a servo valve is used as the flow control valve 73, it is possible to achieve low punching noise and high-precision molding. Furthermore, if a simple punching process is sufficient, it can be constructed at a low cost by using a general commercially available switching valve or flow controller.

It should be noted that the present invention is not limited to the embodiments described above, but can be implemented in other embodiments by making appropriate changes. Although this embodiment has been explained using a turret punch press as an example, it is also applicable to other punch presses, bending machines, shearing machines, and other plate processing machines. In addition, by stacking the low-pressure large-flow pump 49A and the high-pressure small-flow pump 49B so that they can be switched freely, they can be fully used for driving a hydraulic motor, for example, and can be used for either two pressures, two flow rates, or one pressure, one flow rate. It is usable.

[0037]

[Effects of the Invention] As can be understood from the above description of the embodiments, according to the present invention, since the configuration is as described in the claims, it is possible to switch between low pressure large flow rate and high pressure small flow rate. It has become possible to control the hydraulic cylinders that can be used, which requires less output from the pump drive motor, and the pump itself can be small enough. By using it in processing machines, it is possible to further reduce noise.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating a method of controlling a hydraulic cylinder that moves a ram up and down in a turret punch press.

FIG. 2 is a configuration block diagram for controlling the hydraulic cylinder in FIG. 1;

FIG. 3 is an explanatory diagram showing the movement of a ram when punching is performed in cooperation with a punch and a die.

FIG. 4 is a front view of a turret punch press using this hydraulic cylinder.

[Explanation of symbols]

1 Turret punch press (plate processing machine) 17 Punch 19 Die 21 Ram 23 Hydraulic cylinder 33 Piston 35U Upper cylinder chamber 35D Lower cylinder chamber 37 Pressure sensor 41 Position sensor 45 Switching valve 49 Double pump 65 Switching valve 73 Flow rate control valve 75 Control Device

Claims (5)

[Claims] [Claim 1] When a piston rod integrated with a piston provided in a hydraulic cylinder is expanded and contracted, the expansion and contraction movement of the piston rod is controlled by a hydraulic pump with two pressures and two flow rates. How to control hydraulic cylinders. 2. The method of controlling a hydraulic cylinder according to claim 1, wherein the hydraulic pump is a dual pump of high pressure, small flow rate and low pressure, large flow rate. 3. The method of controlling a hydraulic cylinder according to claim 1, wherein the hydraulic pump is provided with a high-pressure, small-flow pump and a low-pressure, large-flow pump and is controlled in a switchable manner. 4. A hydraulic cylinder equipped with a piston rod integrated into a piston, a pressure sensor that detects the pressure within the hydraulic cylinder, a position sensor that detects the position of the expansion and contraction movement of the piston rod, and the hydraulic cylinder. A hydraulic cylinder comprising: a dual-pressure, dual-flow pump for supplying and discharging oil to a hydraulic chamber within the cylinder; and a control device for controlling the pressure sensor, position sensor, and pump. Control device. 5. A plate processing machine that processes a plate into a workpiece by making an upper die and a lower die cooperate by vertical movement of a ram attached to a hydraulic cylinder, and a pressure sensor for detecting the pressure in the hydraulic cylinder. a position sensor for detecting the vertical movement position of the ram; a dual pump having a high-pressure small flow rate and a low-pressure large flow rate pump for supplying and discharging the hydraulic chamber in the hydraulic cylinder; A plate processing machine comprising: a switching valve that switches oil from a pump to a cylinder chamber of the hydraulic cylinder; and a control device that controls the pressure sensor, the position sensor, and the switching valve.