JPH07109255B2 - Pulsed fluid pressure control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a fluid pressure control device capable of arbitrarily changing the pressing force of an actuator during its operation.

"Prior Art" Conventionally, as a device for controlling fluid pressure such as hydraulic pressure and air pressure, there is one that controls a fluid pressure generated by a fluid pressure generation device by using an electromagnetic proportional control valve.

[Problems to be Solved by the Invention] However, the range in which this electromagnetic proportional control valve can control the fluid pressure is, for example, about 3 to 200 kilograms per square centimeter in the case of hydraulic pressure. It was impossible to control continuously over a wide range. In order to eliminate the drawbacks, the present invention aims to provide a fluid pressure control device capable of controlling the fluid pressure to be supplied to an actuator by supplying a high pressure fluid in a pulsed manner. Is.

"Means for Solving the Problems" A pulsed fluid pressure control device of the present invention to achieve the above-mentioned object, an actuator having a large-diameter piston that reciprocates, a fluid path and a pump communicating with this actuator,
In a fluid pressure circuit provided with a switching valve that switches the fluid passage to reciprocate the piston of the actuator, insert the block connected to the fluid passage and the hole connected to the fluid passage of the block, Is connected to the fluid path, and the other end is in contact with the actuator plate, a small-diameter actuator, a pressure spring that pushes this actuator through the actuator plate, and a preload of the pressure spring that presses this small-diameter actuator. A counter spring, an elastic force conversion device that changes the elastic force that presses the small-diameter actuator by pressing the pressure spring, a position indicating member that determines the position of the actuator plate, and an actuator that connects one to the fluid path and the other to the tank. An on-off valve that opens and closes when the position of the plate approaches and separates from the position indicated by the position indicating member, and between the on-off valve and the block When In the body passage pressurized in the direction of forward movement of the piston of the Akuchieta communicates fluid,
In addition, a check valve that holds the pressure of the actuator, or a valve that opens the fluid path when the actuator moves back, a pressure sensor that detects the pressing force of the actuator, and an elastic conversion based on the output signal of this pressure sensor. A control device that operates the device is provided, and the position where the pressing force of the pressure spring of the elastic force converter that pushes the actuator balances with the counter spring and becomes zero or the minimum is the origin of the position indicating member, and the opening and closing is performed at this origin position. Close the valve, adjust the opening / closing valve so that the opening / closing valve opens at a predetermined position when the actuator moves by pressing the pressing spring, and then adjust and set the pressing force of the pressing spring. The on-off valve is opened and closed according to the moving actuator plate to control the fluid pressure in a pulsed manner.

"Action" The pressure fluid supplied from a pump that generates a predetermined high fluid pressure to an actuator having a large-diameter piston is also supplied to a block in which a small-diameter actuator is inserted and pushes the actuator, while an elastic force conversion device that pushes the actuator. The pressure of the pressure spring can be reduced to zero by the actuator by pushing the pressure of the pressure spring or the weight of other parts by the counter spring. Therefore, the pressurizing spring of the elastic force converter can change the pressure applied to the actuator from zero to an arbitrary height. Then, the position where the pressing force becomes zero or the minimum is set as the origin of the position indicating member, the opening / closing valve is closed at this origin position, and the opening / closing valve is opened so that the opening / closing valve is opened when the actuator pushes the pressure spring and moves. After adjusting, the pressing force of the pressure spring is adjusted manually or by a controller to set. After that, by moving the actuator plate with a small-diameter actuator against the set pressure of the pressure spring, the on-off valve can be opened and closed to supply the fluid pressure in a pulsed manner to the actuator. Therefore, by maintaining the pressure of the fluid supplied to the actuator and controlling the pressure of the pressure spring to change based on the signal of the pressure sensor and the designated pressure value, a large diameter Controls the pressing force of the actuator.

[Examples] The present invention will be described with reference to the drawings. In FIG. 1, there is a large-diameter fluid pressure cylinder 1 and an actuator 3 having a large-diameter piston 2 that reciprocates, and the present invention changes the fluid pressure supplied to the actuator 3 from low pressure to high pressure. To control over a wide range.

Fluid path 4 in fluid paths 4 and 5 connected to fluid pressure cylinder 1
Is connected to a tank 8 constituting a commercially available electric pump 7 through a switching valve 6 which holds the pressure in the neutral position.
The fluid path 5 is connected to a low-pressure and high-flow rate pump 9L and a high-pressure and low-flow rate pump 9H, which form a fast-forward fluid pressure source, through a switching valve 6, and these pumps 9H and 9L are connected to a motor 10 and driven. . 11.12 is a relief valve, 13 is a filter, and the check valve 14 in the electric pump 7 is used to prevent high pressure fluid from entering the low pressure fluid path. A flow control valve 15 sets the moving speed of the piston 2. A pressure sensor 16 provided in the fluid passage 5 detects the pressure in the fluid passage 5 and sends a signal to the control device 17. The fluid path 5 of the block 18 connected to the fluid path 5
A small-diameter actuator 22 sealed with a seal 20 and a seal pusher 21 is inserted into the hole 19 connected to the actuator 19, and the other of the actuators 22 moves with the actuator 22.
The actuator plate 23 fixed to 23 or brought into contact with its tip (not shown) can be moved by using, for example, a bar 40 fixed between the base plate 24 fixed to the block 18 and the top plate 25 as a guide. The pressure plate 27 that changes the elasticity applied to the actuator plate 23 by pressing the pressure spring 26 that presses the actuator plate 23 is also supported so as to be movable to the bar 40. As a device that constitutes an elastic force converting device that changes the elastic force by pressing the pressure spring 26, a shaft portion of a screw 29 screwed to a nut 28 fixed to a pressure plate 27 is used as a bearing.
It is supported on the top plate 25 via 30, and is connected to a servomotor 31 such as a pulse motor or AC or DC motor that can control the rotational position with electric pulses, in order to detect the position of the nut 28, etc. Signal of encoder 32 used and pressure sensor 16
And the set pressure input to the control device 17 are compared, and the control device 17 drives and controls the servo motor 31. On the other hand, a counter spring 33 that counters the preload of the pressure spring 26 that pushes the actuator 22 and the weight of the actuator plate 23, etc. is provided, and the preload of the pressure spring 26 and the weight of the actuator plate 23 and the counter spring 33 are balanced. A stopper 34 for stopping the actuator plate 23 that constitutes the position indicating member at the predetermined position is provided, and a bolt 36 fixed to the actuator plate 23 with a screw nut 35 is provided. At the end of this bolt 36, bolt 36
Open / close valve 37 with adjustable timing
Is provided upstream of the valve 38 that holds the pressure of the actuators 3, 22. When a normally open on / off valve is used as the on / off valve 37, one is connected to the fluid passage 5 and the other is connected to the tank 8
When the stopper 34 supporting the position of the actuator 22 is separated from the base plate 24, the fluid path is opened to circulate the pressure fluid to the tank 8. When a normally closed on-off valve is used as the on-off valve 37, when the stopper 34 contacts the base plate 24, the fluid path is opened to send the pressure fluid to the actuators 3 and 22, and the stopper 34 is separated from the base plate 24. Close the fluid path. Although the opening / closing valve 37 has been described as being operated by the bolt 36, a switch (not shown) may be operated by the bolt 36 and the valve may be operated by the switch, or the switching valve 6 may be switched by the switch. You can The valve 38 allows the fluid to pass therethrough when pressurizing the piston 2 of the actuator 3 in the forward direction in the fluid path 5 between the on-off valve 37 and the block 18, and holds the pressure of the actuator 3.
It is a valve that opens the fluid passage 5 when returning. Although a check valve for opening the fluid passage 5 by the pilot pressure of the fluid passage 4 is provided in the figure, when the switching valve 6 is provided between the actuator 3 and the block 18, it may be a simple check valve. As described above, the pressure sensor 16 for detecting the pressing force of the actuator 3 and the control device 17 for activating the elastic force conversion device based on the output signal of the pressure sensor 16 are provided. Alternatively, the stopper 39 may be fixed to the base plate 24 with the nut 40 so that the actuator plate 23 stops at the distance d at which the open / close valve 37 is completely opened, and this position may be set as a predetermined position with the origin. This distance d is an on-off valve
When 37 uses a solenoid valve that operates by a switch, it corresponds to a delay circuit provided in the control device 17 because it prevents the vibrationally opening and closing of 37. The stopper 34.39 may be a stopper 43 provided with a collar 41.42 as shown in FIG.
Many parts of the counter spring 33 are buried in the block 18, and the pressure spring 26 pushes the upper part so that the actuator plate 23 comes into contact with the block 18 or the base plate 24. Alternatively, the opening / closing valve may be controlled to open / close with the position as the origin.

In the case of increasing the pressure of the actuator 3 in FIG. 1,
The servo motor 31 is driven manually or by a command from the control device 17, and the nut 28 and the pressure plate 27 stop the position where the pressure spring 26 is compressed by a predetermined amount.
To switch the high pressure fluid of the pump 9H to the fluid path 5 and block.
Send to 18. Then, when the pressure in the fluid path 5 rises above a predetermined value, the actuator 22 in the block 18 causes the pressure spring 26 to
The actuator plate 23, which moves while compressing the air, operates a switch (not shown) or directly opens the on-off valve 37 to flow the pressurized fluid into the tank 8 as shown in the drawing, while the reverse operation by the pilot operation is performed. The fluid pressure in the block 18 and the fluid passage 5 whose outflow is blocked by the stop valve 38 is kept at the fluid pressure generated by the actuator 22 pushed by the pressure spring 26.
If the pressure in the fluid path 5 drops, the pressure spring 26
Pushes the actuator 22 down, and the open / close valve 37
By closing the valve and supplying the high-pressure fluid again, the fluid is supplied in a pulsed manner, and the fluid pressure cylinder 1 and the block 18 are supplied.
The internal pressure will be maintained according to the position supported by nut 28 which is moved by screw 29 rotated by servo motor 31.

On the contrary, when it is desired to reduce the applied pressure, the servo motor 31 is rotationally controlled by the predetermined pressure value input to the control device 17 and the pressure sensor 16 or the difference between the pressure detected by the load sensor and the time required for the pressure reduction. By moving the nut 28 upward and extending the pressure spring 26, the pressure in the block 18 and the fluid path 5 is reduced and kept at a lower pressure than before. The fluid pressure at that time is set to the fluid pressure in the block 18 generated by the actuator 22 pushed by the pressure spring 26, and the set value is opened / closed by opening / closing the on-off valve 37 to supply the fluid pressure into the fluid passage 5, and the reverse pressure is applied. Valve 38
Holding at is the same as before.

When reducing the pressure of the fluid, a leak valve such as a well-known throttle valve (not shown) is provided in the fluid passage 5 for holding the pressure by the valve 38 so that the fluid is leaked to quickly reduce the pressure. Good. Then, when the switching valve 6 is switched to send the pressurized fluid to the fluid passage 4, the check valve 38 for pilot operation is opened by the pilot pressure and the piston 2 is moved back.

[Advantages of the Invention] According to the present invention, the pressing force of the actuator is determined by the pressure spring that pushes the actuator, and the pressure of the pressure spring that pushes the actuator is the preload of the pressure spring that pushes the actuator and other parts. The initial pressure to push the fluid in the fluid path can be made zero by balancing with an opposing spring that opposes the weight, so the fluid pressure can be changed from zero to any height, and the elasticity of the pressure spring is adjusted. The fluid pressure can be controlled and maintained by the pressure fluid that is supplied in a pulsed manner by opening and closing the on-off valve at the specified position.Also, a leak valve is provided in the fluid path that retains the pressure to reduce the fluid pressure. By leaking, the pressure can be quickly reduced.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the present invention, and FIG. 2 is a diagram illustrating a stopper. 3 …… Actuator, 4.5 …… Fluid path, 6 ……
Switching valve, 7 ... Electric pump, 16 ... Pressure sensor, 17 ...
Control device, 18 …… Block, 22 …… Activator, 26 ……
Pressure spring, 33 …… Counter spring, 37 …… Open / close valve, 38 …… Check valve.

Claims (2)

[Claims] Claim: What is claimed is: 1. A small-diameter actuator having one end in contact with a fluid path and the other end in contact with an actuator plate, a pressure spring for pressing the small-diameter actuator, and an elastic force conversion for changing the elastic force with which the pressure spring presses the small-diameter actuator. A device, an opposing spring provided to oppose the pressure spring, a valve for holding the pressure of the actuator, and an opening / closing valve for detecting the position of the actuator plate and opening / closing it on the upstream side of the valve are provided. , A pulse for controlling the fluid pressure in a pulsed manner by setting a position where the pressing force of the pressure spring of the elastic force converting device for pressing the actuator and the elastic force of the counter spring are balanced as an origin, and opening and closing the opening / closing valve near the position of the origin. Fluid pressure control device. 2. A pulse-like fluid pressure control device having a leak valve in a fluid passage for holding pressure.