JPH0663523B2 - Linear pulse motor direct connection control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a linear pulse motor direct connection type control valve having a linear pulse motor as a drive portion of a valve body.

(Prior Art) Generally, a hydraulic solenoid valve that can be electrically controlled is a proportional solenoid valve,
There are servo valves, etc. The servo valve is a valve that converts an electric signal as an input into a hydraulic pressure, and is suitable for a servo mechanism that requires a high-speed response.

For example, in a feedback type servo valve, as shown in FIGS. 7 and 8, the magnet coil 42 of the torque motor 41 is
When a current flows as an input to the armature 43, magnetic characteristics are given to the armature 43, and the armature 43 tilts corresponding to the magnitude and polarity of the input current due to the magnetic relationship with the upper and lower magnetic poles. Due to this tilting of the armature 43, the armature 43
The nozzle flapper 44 provided at the tip of the nozzle is displaced. Then, the left and right nozzles arranged on both sides of the nozzle flapper 44
Since the clearance between 45 and 46 changes and the back pressure of both nozzles 45 and 46 changes, as a result, the hydraulic pressures acting on both end surfaces of the spool 47 become unbalanced, and the spool 47 moves due to this difference in hydraulic pressure.

At this time, since the feedback spring 48 provided at the tip of the nozzle flapper 44 is attached to the central portion of the spool 47, it generates a torque that is opposite to the magnetic torque of the armature 43, and the nozzle flapper 44 is in the neutral position. Pull back up. When the nozzle flapper 44 returns to the neutral position, the back pressures of the left and right nozzles 45 and 46 become equal and the spool 4
The 7 stops at that position. In this way, the spool 47 of the servo valve can maintain the valve opening proportional to the polarity and the magnitude of the input current of the torque motor 41.

(Problems to be solved by the invention) However, since the torque motor 41 is conventionally used to drive the nozzle flapper 44 as described above, there is a problem that the coil 42 generates heat due to the input current and power consumption increases, Since it is an analog control, it is easily affected by temperature and the like. Especially, in the case of analog control, the control device for controlling the torque motor 41 is weak against the electric nozzle and is susceptible to temperature drift.

In addition, since many precision parts such as the armature 43 and the nozzle flapper 44 are used, there is a problem that they are vulnerable to dust and are expensive. Furthermore, there is a problem that there is a large loss flow rate because the hydraulic oil always flows through the nozzle flapper 44, and the tilt angle of the armature 43 of the torque motor 41 tends to cause hysteresis due to friction or the like, and there is also a problem that the machine difference becomes large. It was

The present invention has been made in view of the problems that the conventional analog control valve is susceptible to electrical noise, and the problems that the conventional technology cannot deal with when complicated control is desired.

Configuration of the Invention (Means for Solving Problems) The linear pulse motor direct connection type control valve of the present invention is controlled and driven by a digital control signal, and a linear pulse motor whose output shaft advances and retracts in a stepwise manner and a small chamber which communicates with each other. In addition to the large chamber, a driving unit having a small cross-sectional area is slidably arranged in the small chamber, and the driving unit is configured to slide based on the forward / backward movement of the output shaft of the linear pulse motor, A driven body having a large cross-sectional area is slidably disposed in the large chamber, and a hydraulic booster mechanism for sealing a fluid in a working chamber formed between the driving body and the driven body, A hydraulic control spool that is slidably provided integrally with a driven body of the booster mechanism and that is displaced according to a displacement amount reduced by the hydraulic booster mechanism.

(Operation) With the above configuration, when the linear pulse motor inputs the digital control signal, the output shaft of the linear pulse motor is stepped or retreated stepwise, and the driving body of the hydraulic boost mechanism is slid in the small chamber. Then, the driven body slides via the fluid in the working chamber, and the hydraulic control spool is displaced stepwise along with the driven body according to the displacement amount reduced by the hydraulic booster mechanism.

(Embodiment) A preferred embodiment embodying the present invention will be described below with reference to FIGS.

A spool 2 constituting a four-way pilot valve is arranged in the valve hole 1a of the valve body 1 so as to be slidable in the left and right directions.
Is located at the left side position of the valve hole 1a as shown in FIG. 3, the hydraulic oil flows from the supply port 3 to the actuator port 4 communicating with the cylinder (not shown) via the spool 2 and other actuators. Hydraulic fluid flows from the port 5 to the return port 6a. or,
When the spool 2 is located on the right side of the valve hole 1a as shown in FIG. 4, hydraulic oil flows from the supply port 3 to the actuator port 5 via the spool 2 and operates from the actuator port 4 to the return port 6b. The oil is flowing.

The supply port 3 is connected to an oil tank 9 via an oil passage 7 and an oil pump 8, and the return ports 6a, 6
b is connected to the oil tank 9 via an oil passage 10.

Hydraulic boosters A and B arranged on both left and right sides of the spool 2.
Will be described.

Since both hydraulic boosting mechanisms A and B are the same mechanism, one hydraulic boosting mechanism A will be described for convenience of description, and the other hydraulic boosting mechanism B will be denoted by the same reference numeral and description thereof will be omitted.

A linear pulse motor 13A is fixed to one side of the body 11 via a bracket 12. Corresponding to the linear pulse motor 13A, the left and right parts of the body 11 are small chambers 1
A working chamber 17 composed of 5 and a large chamber 16 is formed. The small chamber 15 has a small-diameter piston as a driving body having a small sectional area.
18 is slidable in the left-right direction and the large chamber 16
A large-diameter piston 19 as a driven body having a large cross-sectional area is also arranged in the same direction so as to be slidable in the left and right directions.
A fluid such as hydraulic oil is sealed in the working chamber 17 surrounded by the spaces.

Working chamber 17 consisting of the small chamber 15 and the large chamber 16, a small diameter piston 1
The hydraulic booster A is composed of 8 and the large-diameter piston 19.

The motor rod 14 of the pulse motor 13A is brought into contact with the small diameter piston 18 and presses the small diameter piston 18 via the motor rod 14 when the linear pulse motor 13A is driven. Further, the drive end of the large-diameter piston 19 is disposed in contact with the left end of the spool 2. The other hydraulic booster mechanism B is driven by the linear pulse motor 13B and the large-diameter piston 1
9 is disposed in contact with the right end of the spool 2.

As shown in FIG. 2, a device for controlling the linear pulse motors 13A, 13B for driving both the hydraulic boosters A, B is a digital control signal from a control device (hereinafter referred to as a microcomputer controller) 20 equipped with a microcomputer as shown in FIG. The control pulse signal as is appropriately output to the motor driver 21. Then, the motor driver 21 outputs a drive signal to the linear pulse motors 13A, 13B based on the control pulse signal, and the linear pulse motors 13A, 13B use the drive signal to cause the linear pulse motors 13A, 13B to move their motor rods 14 in the same direction and at the same movement amount. It is designed to be step driven.

The operation of the linear pulse motor direct connection type control valve configured as described above will be described.

Now, in FIG. 1, the spool 2 is in the neutral position. When a control pulse signal for fully opening the spool to the left position is output from the microcomputer controller 20 to the motor driver 21 in this state, the motor driver 21 outputs a drive signal to each linear pulse motor 13A, 13B based on the control pulse signal. Output. Then, the linear pulse motor 13B digitally steps the motor rod 14 to the left based on the drive signal, and presses and drives the small diameter piston 18. Then, the large-diameter piston 19 is also driven via the hydraulic oil in the working chamber 17.

At this time, the displacement amount of the large-diameter piston 19 becomes
18 area / area of large-diameter piston 19] in proportion to the displacement of the small-diameter piston 18.

The driving force of the large-diameter piston 19 is proportional to [area of large-diameter piston 19 / area of small-diameter piston 18].
Driving force is increased. On the other hand, linear pulse motor
Simultaneously with the operation of the linear pulse motor 13B, the motor 13A of the motor 13A moves backward to the left with the same amount of movement as the motor rod 14 of the linear pulse motor 13B, based on a drive signal.

As a result, the spool 2 is located on the right side of the hydraulic booster mechanism B.
It is pressed and driven by the large-diameter piston 19 to move leftward to the fully open position.

By moving the spool 2 to the left, the supply port 3 and the actuator port 4, and the return port 6a and the actuator port 5 communicate with each other as shown in FIG. The hydraulic oil flows to port 4 and actuator port 5
Hydraulic fluid flows from the return port 6a.

Contrary to the above, when the control pulse signal for fully opening the spool to the right position is output from the microcomputer controller 20 to the motor driver 21 when the spool 2 is in the neutral position, the motor driver 21 outputs each linear signal based on the control pulse signal. The drive signal is output to the pulse motors 13A and 13B. Then,
Based on the drive signal, the linear pulse motor 13A digitally steps the motor rod 14 to the right and presses and drives the small diameter piston 18. Then, the large-diameter piston 19 is also driven via the hydraulic oil in the working chamber 17.

At this time, the displacement amount of the large-diameter piston 19 is
18 area / area of large-diameter piston 19] in proportion to the displacement of the small-diameter piston 18.

The driving force of the large-diameter piston 19 is proportional to [area of large-diameter piston 19 / area of small-diameter piston 18].
Driving force is increased. On the other hand, linear pulse motor
Simultaneously with the operation of the linear pulse motor 13A, 13B digitally retracts the motor rod 14 to the right with the same moving amount as the moving amount of the motor rod 14 of the linear pulse motor 13A based on the drive signal.

As a result, the spool 2 is located on the left side of the hydraulic booster mechanism A.
It is pressed and driven by the large-diameter piston 19 and moves rightward to the fully open position.

This movement of the spool 2 to the right causes the supply port 3 and the actuator port 5 to communicate with each other, and the return port 6b and the actuator port 4 to communicate with each other as shown in FIG. Hydraulic fluid flows to port 5 and actuator port 4
Hydraulic fluid flows from the return port 6b.

Although the spool 2 is opened at the fully open position in the above description, when the control pulse signal output from the microcomputer controller 20 means, for example, the half open position to the right, the motor driver 21 is based on the control pulse signal. The drive signal is output to each of the linear pulse motors 13A and 13B. Then, the linear pulse motors 13A and 13B step forward and backward respectively to the motor rod 14 based on the drive signal to digitally move the spool 2 to the right through the hydraulic boosting mechanisms A and B. Drive it to half open.

In this way, the displacement amount of the spool 2 can be arbitrarily set according to the control pulse signal of the microcomputer controller 20. That is, when the solenoid is used for the drive unit, the solenoid is excited and demagnetized only by the on / off control. In this case, the valve has only two stroke positions of fully closed or fully opened. On the other hand, the linear pulse motors 13A and 13B can precisely and digitally control the opening degree of the spool 2.

Therefore, the stability is excellent and the hysteresis is small. As a result, since the spool 2 is accurately positioned, open loop control becomes possible.

In addition, the linear pulse motors 13A and 13B generally have a small driving force, but the driving force of the motor rod 14 is the hydraulic booster A,
Since it is amplified from B, it is possible to sufficiently provide the driving force necessary for driving the spool 2. Further, due to the holding force of the linear pulse motors 13A and 13B, it is not necessary to supply electric power when the spool 2 has a constant opening.

Moreover, since the linear pulse motors 13A and 13B are used,
Easy to connect to a microcomputer, microcomputer controller
By inputting data relating to the flow rates of the actuator ports 4 and 5 for realizing the displacement of the actuator (not shown) to 20, the control valve can be controlled by programming.

Next, a second embodiment will be described with reference to FIG.

In this embodiment, in the structure of the first embodiment, a pair of linear pulse motors 13A, 13A arranged on the left and right of the valve body 1 are used.
Instead of B, a single linear pulse motor 23 is provided, and motor load 24a, 24b driven from the left and right ends of the linear pulse motor 23 in the same direction by the same movement amount are provided in a protruding manner. In addition, a bracket that supports the linear pulse motor 23
Both ends of 12 are fixed to the body 11 of a pair of hydraulic boosting mechanisms A and B, which are arranged so that their small diameter pistons 18 face each other, and the small diameter pistons 18 of both hydraulic boosting mechanisms A and B are the above-mentioned motors. It is in contact with the rods 24a and 24b. The difference is that the small chambers 15 of the hydraulic boosters A and B are extended to the left and right sides of the valve body 1.

Therefore, in this embodiment, unlike the first embodiment, since only one linear pulse motor is required, the control is easy and the structure is simple, and the manufacturing cost can be reduced.

Next, a third embodiment will be described with reference to FIG.

In this embodiment, in the structure of the second embodiment, instead of driving both ends of the spool 2 with the large-diameter pistons 19, the drive rod 26 is connected to the left end portion of the spool 2 via the connecting rod 25.
Are connected and fixed, and driven projections 27 and 28 are projected from both ends of the drive rod 26. Then, the small chambers 15 of the hydraulic boosting mechanisms A and B arranged on both sides of the linear pulse motor 23 are formed to be short, and the linear pulse motor 23 and the hydraulic mechanisms A and B are both formed.
Are integrated into a unit, and the unit is arranged between the driven projections 27 and 28 of the drive rod 26 to provide the hydraulic pressure mechanisms A and B.
The difference is that the large-diameter pistons 19 are arranged so as to abut on the driven projections 27 and 28, respectively.

Therefore, in this embodiment, the displacement of the motor rods 24a and 24b of one linear pulse motor 23 appears as the displacement of the spool 2. Further, in this embodiment, the linear pulse motor 23 and the hydraulic boosting mechanisms A and B are unitized, so that it can be diverted to a precision positioning device.

It should be noted that the present invention is not limited to the above-mentioned embodiment, and can be arbitrarily modified within a range not departing from the spirit of the present invention.

EFFECTS OF THE INVENTION As described in detail above, according to the present invention, the displacement amount can be arbitrarily set corresponding to the digital control signal of the control device, and the spool opening can be controlled accurately and digitally. Further, since the linear pulse motor is driven by a digital control signal, it is resistant to noise, excellent in stability and less in hysteresis.

In particular, since the displacement amount of the linear pulse motor is reduced by the hydraulic boost mechanism, the positioning accuracy of the spool can be improved and the spool can be reliably driven even with a small driving force of the linear pulse motor. it can.

The holding force of the linear pulse motor eliminates the need for electric power when the spool is at a constant opening, thus saving energy. Further, unlike the conventional art, since precision parts such as a nozzle flapper are not required, it is resistant to dust in hydraulic oil, has high reliability, and can reduce manufacturing cost, which is an excellent industrial application. Is.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment embodying the present invention, and FIG.
FIG. 4 is an electric circuit diagram, FIG. 3 is a sectional view of an essential part showing the action of the spool, FIG. 4 is a sectional view of an essential part showing another action of the spool, and FIG. 5 is a sectional view of the essential part of the second embodiment. , FIG. 6 is the third
FIG. 7 is a sectional view of a main part of the embodiment, FIG. 7 is a sectional view of a conventional servo valve, and FIG. 8 is a sectional view of a state in which the spool holds the valve opening degree from the state of FIG. 1 is a valve body, 2 is a spool, 3 is a supply port, 4 and 5 are actuator ports, 6a and 6b are return ports, 8 is an oil pump, 9 is an oil tank, 13A and 13B are linear pulse motors, 15 is a small chamber, 16 is a large chamber, 17 is a working chamber, 18 is a small diameter piston, 19 is a large diameter piston, 20 is a microcomputer controller (control device), 21 is a motor driver, 23 is a linear pulse motor, A and B are hydraulic boosters. is there.

Claims (1)

[Claims] 1. A linear pulse motor which is controlled and driven by a digital control signal and whose output shaft advances and retreats in a stepwise manner, and a small chamber and a large chamber which communicate with each other. In addition to being movably arranged, this driving body is configured to slide based on the forward / backward movement of the output shaft of the linear pulse motor, and a driven body having a large cross-sectional area is slidably arranged in the large chamber, The working chamber formed between the driving body and the driven body is provided with a hydraulic booster mechanism that seals fluid, and is slidably provided integrally with the driven body of the hydraulic booster mechanism. A linear pulse motor direct connection control valve having a hydraulic control spool that is displaced according to the amount of displacement reduced by the force mechanism.