JPS58196306A - Position control device for fluid pressure piston - Google Patents

Abstract

PURPOSE:To have a high-accuracy positional control of a piston by putting a pressure chamber installed on the side of piston's sliding direction and another pressure chamber on the other side in communication selectively with the pressure passage and drain passage through a spool and thereby reducing influence of external turbulences. CONSTITUTION:A piston 4 is fitted in a piston room 2 slidably and divids No.1 pressure chamber 9 and No.2 pressure chamber 10 on the sides in the sliding direction. When a pulse motor 7 is fed with a pulse signal to drive a motor 7, a spool 5 moves to the right for a certain specified distance to allow a switching port 42b to have communication with a drain port 44, and then No.1 pressure chamber 9 will be open to the tank through the drain passage 12. Consequently the pressure fluid introduced in No.2 pressure chamber 10 acts so as to move the piston 4 to the right.

Description

[Detailed description of the invention]

The present invention relates to a position control device, and more particularly to a position control device for a hydraulic piston that performs fluid control. Conventionally, when controlling the position of a piston, the piston is driven using a torque motor or a main smoker, but each of these motors is of an analog type, and is used to improve the performance of, for example, poppet-type pressure control devices. If the position of the regulating valve is controlled with high precision using a computer, the control *J system will be complicated, such as the need for a D transformer, and the position control piston will require a feedback mechanism. is required, which increases costs, and since the aperture control section and pressure control section are controlled by the movement of the position control piston, control stability is poor, and overshoots and undershoots occur in the same layer. be. On the other hand, digital pulse motors, whose rotation angle and speed can be controlled by pulse voltage, have the characteristics of providing highly flexible computer control, relatively large output torque, and good reproducibility. It is known that the motor can be used in place of an analog type such as a torque motor, as shown in Japanese Utility Model Publication No. 56-11'5201. In this conventional example, as shown in Fig. 1, a piston is installed in the cylinder hole CB of the main body (&).

0] is slidably supported, and an inner rod (F
) protrudes and its tip is located in the train chamber CG), and a nozzle (H) is provided at the tip of this internal rod (ν), facing inside the end (C) of the rod (1), and The nozzle (H) is opened and closed by the inner end (C), while the rod is driven by a step motor operated by a digital signal via the pinion (R), and Of the cylinder chambers (L) with different areas provided on both sides of the piston (0) * (M), pressure fluid is guided to the cylinder on the small area side: !1 (L), and the cylinder chamber on the large Ti volume side is introduced (M) through the constrictor (1).In other words, in the conventional example configured as above, the rod is actuated by the drive of the step motor, Said end (m(
By changing the distance between J) and the nozzle (11),
The way the cylinder chamber (M) comes out is changed, and the piston (
The position of the piston (0) can be controlled by moving the piston (0) with a large force amplified by the writing pressure. In other words, the nozzle (H) and the rod (TJ) constitute a nozzle flapper type amplification mechanism, which can be driven by a digital signal and can control the position of the piston (0) even with a small output torque. According to the nozzle 7 ripple type amplification mechanism configured as described above, there is always leakage flow from the nozzle (CB) to the drain chamber (G), resulting in power loss and There are problems such as a layer of dust depositing on the piston (0), resulting in a decrease in precision, and a change in the viscosity of the fluid, particularly oil, due to changes in temperature, resulting in fluctuations in the position control of the piston (0). The present invention has been achieved in order to solve the problems of the conventional examples described above by utilizing a driving means such as a pulse motor operated by a pulse signal. The movement of the spool is made to slide in conjunction with the spool, and the piston follows the movement of the spool, so that the piston can be controlled to a position corresponding to the position of the spool. This makes it possible to perform highly accurate position control with little influence on the position. Therefore, the configuration of the present invention is a position control device for a fluid pressure piston that is slidably supported by a main body and is configured to perform fluid control, wherein a spool hole is formed in the piston, and a spool hole is formed in the piston. The spool is slidably supported, and the spool protrudes from the main body to be driven by a driving means operated by a pulse signal. A second pressure chamber is provided, the first pressure chamber is selectively communicated with the pressure passage and the drain passage through the spool, and the position of the piston is controlled by the operation of the driving means. This makes it possible to control the piston to a position corresponding to the position of the spool operated by the driving means. Next, an embodiment of the present invention will be described based on a decoy vehicle. What is shown in Fig. 2 is a pressure control unit (Y) e connected to the position control device (X) of the present invention to form a pressure control device as a whole.1 The position control device (X) is a main body. (1)
and a piston (4) slidably housed in the main body (1).
), a spool (5) slidably housed inside the piston (4), and a pulse motor (7) serving as a driving means for the spool (5). The main body (1) has a piston chamber.

In addition to providing [2],
The piston chamber (2) is provided with a pressure passage (11) communicating with a second pressure chamber (10) to be described later and a drain passage (12). Further, the piston (4) is housed in the piston chamber (2) so as to be able to freely slide therein, and first pressure chambers (9) are provided on both sides in the sliding direction.
1 and the second pressure chamber (10), and the first pressure chamber (9) is equipped with the spring (21) for returning to the origin. The piston (4) also has a piston hole (3) that opens laterally on the second pressure chamber (10) side, and a rod (41) that extends from the side surface of the first pressure chamber (9) to the outside of the main body (1). ), and the fA1 pressure chamber (9) of the piston (4) is provided.
) The side direction is the first pressure receiving thll (45), the second pressure chamber (1
D) The side surface is the second receiving pressure Efi (46), and the first receiving pressure f
The area of ii (45) is made larger than the -product of the second received pressure Efi (46). Furthermore, the piston (4)
has a communication port (4) communicating with the first pressure chamber (9).
2&), switching port (42b), and 11!2 pressure chamber (1
A pressure port (43) for introducing pressure fluid pressure through the drain port (43) and a drain port (43) communicating with the drain passage (12)
4) are respectively opened, and the spools [
5], the pressure port (46) and communication port (
421L) or the drain port (44) and the switching port (42kl) are configured to selectively communicate with each other. The spool (5) is connected to the piston.

In [4], the other side of the spool (5) is made to protrude to the outside of the main body (1), and a rack (6) is formed on this protrusion. Moreover, the spool (5) is of a three-land type, and by moving the intermediate land (51), the pressure capo (43) or the switching port (
42kl) is selectively opened, and the intermediate land (51) and each port (42kl), (43)
It is preferable that the spool (5) has zero wrap. Furthermore, a spring chamber (20) is provided on the forward side of the spool (5) and communicates with the drain passage (12) via an internal passage (5&). (2o) is a spring (2) for returning to the origin.
2) Interior. As the driving means, a pulse motor (7) operated by a pulse signal is used, and a pinion (7) is attached to the drive shaft of the motor (7).
8], and the binion (8) is attached to the rack of the spool (5).

It meshes with [6]. In addition, the pressure control part (the frame body (47) and the valve seat (16a)
a pressure regulating valve (48);
It consists of a repressive body (17). The frame body (4) includes an inlet (13) for introducing fluid discharged from the pump, and an outlet (14) for discharging the fluid.
The fitting opening (15) into which the rod (41) of the piston (4) is fitted is opened, and the pressing body (
The - side of 17) is fixed to the tip of the rod (41) that is inserted from the fitting opening (15) via the spring receiver (49), and the other side of the pressing body (17) is fixed to the tip of the rod (41) that is fitted through the fitting opening (15). Valve (48)
It locks in place. The valve (48) is opposed to the valve seat (16&), and the distance between the adjustment 11F (48) and the valve seat (16&) can be adjusted by moving the piston (4), thereby adjusting the fluid pressure. It will be done as it is. Next, the origin of the piston (4) is set and the piston (
4) The mechanism for returning to the origin will be explained. (18) is a cover that covers the external protrusion of the spool (5), and has a drain hole (181L) at the bottom. A stopper (19) facing the back of the spool (5) is provided on the cover (18).
is provided, and the origin position of the piston [4] is determined by the length of the stopper (19). This origin is the position of the piston (4) where the regulating valve (48) of the pressure control section (48) is fully open. , said spool

[5] is moved by the spring (22) to a position where it contacts the stopper (19), and the piston (4) is
by the action of the spring (21), the main body (1) moves to a position where it comes into contact with the end surface of the second pressure chamber (10);
The pressure port (43) and the switching port (42m) are closed by the intermediate land (51), and the regulating valve (48) of the pressure control section (Y) is fully open.Next, as explained above, Explaining the operation of the embodiment When the piston (4) and spool (5) have returned to their origin, when a pulse signal is input to the pulse motor [7] to drive the motor (7), the pinion This movement of the spool (5) in which the spool (5) moves a predetermined amount to the right via (8) and the rack (6)! vIii is determined by the rotation angle of the motor (7) driven in response to the pulse signal, and the movement of the spool (5) causes the switching port (42b) to switch to the drain port (44). Through,
The first pressure chamber (9) opens to the tank CT via a drain passage (12). As a result, the fluid pressure acting on both ends of the piston (4) changes, and due to the action of the pressure fluid introduced into the second Tagata chamber (10) via the pressure passage [11], the piston (4) ) moves to the right. The movement of this piston [4] follows the movement of the spool (5), and this movement amount is equal to the amount of movement of the spool (5).
This corresponds to the amount of movement in 5). That is, the movement of the piston (4) to the right is 1. sI first and second pressure chambers (9),
(10), by changing the pressure acting on both ends of the piston (4), in the static equilibrium position, i.e., at the drain port (44kl) of the switching port (42kl).
) to a position where communication with them is cut off. As described above (the piston (4) is
It moves to the right with a large force amplified by the fluid pressure acting on the spool (5), and reaches the resting equilibrium position, that is, the spool (5)
), and this movement of the piston (4) causes the rod (41) to control the pressure!
Move the suppressor (17) of (Y) and move the pressure regulating valve (
48) is brought close to or in close contact with the valve seat (164), the pressure of the fluid discharged from the discharge port (14) can be controlled. Further, as described above, the pressure regulating valve (48) or the valve seat (1
When the motor (7 &) is close to or in close contact with the motor (7 &)
) in the opposite direction to the sprung force passage (11) t! 1
It passes. As a result, the pressure in the first pressure chamber (9) is reduced to the second pressure chamber (9).
10), and the second received pressure lf[I(46)
Since the area of the first receiving pressure Efi (45) is larger, the piston (4) moves to the left. The movement of this piston (4) also follows the movement of the spool (5), and the amount of movement also follows the movement of the spool (5).
This corresponds to the amount of movement in 5). That is, the movement of the piston (4) to the left is carried out by the area difference in the direction of action of the pressure chambers (9) and (10) facing each other, and the piston (4) is moved to the static equilibrium position, that is, the piston (4) is moved to the left. The switching bow (43b) moves to a position where communication with the pressure port (243) is cut off. Also in this case, the piston (4)
It moves to the left due to a large force amplified by the fluid pressure acting on the piston (4), and stops at a static equilibrium position, that is, a position corresponding to the position of the spool [5], and the left side of this piston (4) This piston (
4), the rod (41) moves to the left, and the rod (41) moves to the left.
The pressure regulating valve (
48) moves to the left and can adjust the pressure of the fluid flowing out of the discharge port (14).As described above, the piston (4) follows the movement of the spool (5) and the spool Since the movement amount can be controlled to match the movement amount of (5), by accurately operating the spool <5) with the pulse motor (7), the position of the piston (4) can be controlled, and therefore the pressure can be controlled accurately. Moreover, since the piston (4) can be moved with a large force amplified by fluid pressure, there is no need to increase the output of the motor (7), and the piston (4) can be moved powerfully and accurately with a small output. In addition, the position of the piston (4) can be controlled by the spool (5).
Since the pressure fluid introduced into the pressure chambers (9) and (10) to operate the piston (4) may change in viscosity due to changes in hot water temperature, or dust may enter the sliding parts. Even if the pressing force acting on the piston (4) changes due to intervention, the effect on control accuracy is small (
It can be done. Furthermore, according to the above embodiment, when the input to the motor (7) is released, the springs (20) and (21) automatically return to the origin. In the embodiment described above, the area of the first receiving pressure l1ii (45) is larger than the area of the second receiving pressure 1fi (46) (although
This is to generate a pushing force to make the piston (4) follow it when the spool (5) moves to the left in Figure 2, so the spring (21) has to have that pushing force. If so, the areas of the first and second pressure-receiving surfaces (45) and (46) may be equal.Furthermore, in the above embodiment, a pressure control section is coupled to a position control device; Instead of the pressure control section, a spool-type flow rate control section and a direction control section can be combined and used as a flow rate control device and a direction control device, respectively.As described above, the present invention uses a piston and a spool, The spool is slidably supported on the piston and linked to a driving means operated by a pulse signal, and the piston follows the movement of the spool to control the piston to a position corresponding to the position of the spool. Therefore, even when controlling the flow rate with high precision using a computer, it can be controlled with a simple control system, and the piston position can be controlled stably and accurately, and moreover, it can be controlled using the conventional nozzle flapper type described above. It can be made more compact compared to the mechanism of
It is possible to reduce the influence of external disturbances such as changes and the intervention of dust, and it is possible to perform highly accurate flow control with less influence even in response to output displacement and load fluctuation.

[Brief explanation of drawings]

Figure 1 is a schematic sectional view showing a conventional example, and Figure 2 is a schematic sectional view showing an embodiment of the present invention. (1) - Body (6) Spool hole (4) Piston (5) Spool (7) Pulse motor

[9]--First pressure chamber (10)...Second pressure chamber (43)--Pressure, port (12)--Drain port (42&　)--Communication port (42m))...Switching port (41)...Rod CX)...Position control device (Y)--Pressure control section Agent Patent Attorney Tsu 1) Naohisa

Claims (1)

[Claims] (1) A position control device for a fluid pressure piston that is slidably supported by a main body and is configured to perform fluid control,
A spool hole is formed in the piston, a spool is freely supported in the spool hole, the spool protrudes outside the main body, and is interlocked with a driving means operated by a pulse signal, and the piston slides. first and second pressure chambers are provided on one direction side and the other side, the first pressure chamber is selectively communicated with the pressure passage and the drain passage via the spool, and by the operation of the driving means. , a position control device for a hydraulic piston, which is specially designed to control the position of the piston.