JPH09152055A - Solenoid proportional control valve controlling method and solenoid proportional control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart a dither of fixed amplitude to a valve element regardless of the displaced position of the valve element. SOLUTION: An exciting coil part 30 in a drive 11 has first 32 and second 33 exciting coils on the inner periphery of an outer cylinder part 31 made of a magnetic substance. A bias exciting current consisting of a pulsed current of a fixed frequency and fixed amplitude is supplied to the first exciting coil 32, and a spool 18 is held in its closed position by the bias exciting current. A spool driving current is supplied to the second exciting coil 33, and the spool 18 is driven from the closed position to a target displaced position by the spool driving current. A dither is given to the spool 18 by the bias exciting current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method of an electromagnetic proportional control valve for controlling a flow rate or pressure using a solenoid and an electromagnetic proportional control valve.

[0002]

2. Description of the Related Art An electromagnetic proportional control valve 15 as shown in FIG.
At 0, the spool 153 is arranged at the displacement position corresponding to the exciting current due to the opposing of the driving force generated by the proportional solenoid 151 in proportion to the exciting current and the urging force of the compression coil spring 152. That is, when the exciting current is not supplied to the proportional solenoid 151, the spool 153 is arranged at the right end of the spool chamber 154 by the urging force of the compression coil spring 152. When the exciting current is supplied to the proportional solenoid 151, the spool 153 is driven from the right end to the left end of the spool chamber 154 against the biasing force of the compression coil spring 152 by the driving force of the proportional solenoid 151.

On the other hand, in the solenoid proportional control valve 150, when the spool 153 is arranged at the closed position in the center of the spool chamber 154, the output port 155 is connected to the input port 156.
Also, the exhaust port 157 is not connected. That is, the spool 153 has the closed position as the zero point (that is, the reference position), the direction in which the output port 155 communicates with the input port 156 (that is, the left direction), and the direction in which the output port 155 communicates with the exhaust port 157 ( That is, it is driven in both directions (rightward). Therefore, the exciting current supplied to the proportional solenoid 151 is the current for biasing the spool 153 from the right end of the spool chamber 154 to the closed position, and the current for displacing the spool 153 from the closed position to the displacement position corresponding to the target valve opening. The current is the sum of minutes and.

By the way, in the electromagnetic proportional control valve 150, hysteresis occurs between the exciting current and the displacement position due to factors such as magnetic hysteresis of the magnetic circuit of the proportional solenoid 151 and friction hysteresis of sliding resistance of the spool 153. That is, there occurs a phenomenon that the displacement position for the same exciting current differs depending on the direction in which the spool 153 is driven to the displacement position. Further, the friction between the respective parts, or the parts not easily separating after being left for a long time, deteriorates the sensitivity when the displacement amount of the spool 153 is small.

Therefore, in order to prevent hysteresis and improve sensitivity, a method in which the spool 153 is driven with dithering is generally used. The dither is a method of canceling hysteresis or improving sensitivity by vibrating the spool 153 at each displacement position with a small amplitude in a range that does not affect the displacement position. The dither amplitude is set to an appropriate range because if the size is too small, the dither effect will be low, and if it is too large, it will be a source of vibration and noise.

As a method of giving dither to the spool 153, there is a method of supplying a current obtained by adding a dither signal such as a triangular wave to the exciting current corresponding to the target valve opening as an exciting current to the proportional solenoid 151. However, since the proportional solenoid 151 used for the electromagnetic proportional control valve 150 has a large number of coil turns and a high impedance, the dither amplitude in the above range can be obtained only at a relatively low frequency. As a result, the dither frequency becomes low, and there is a problem that vibration and noise become remarkable.

[0007] In order to solve such a problem, the actual development 5
In the drive device for an electromagnetic proportional control valve disclosed in JP-A-7-186768, the proportional solenoid 151 is driven by a pulse exciting current whose pulse width is modulated based on the target valve opening. The frequency of this pulse excitation current is set to a frequency suitable for dither, and the spool 153 is driven to the target displacement position by the average current. As a result, even in the proportional solenoid 151 having a high impedance, it is possible to provide the spool 153 with dither having an amplitude capable of obtaining a high dither effect.

The dither is applied not only to the spool valve type electromagnetic proportional control valve but also to the poppet valve type electromagnetic proportional control valve. The poppet valve type solenoid proportional control valve is equipped with a pair of poppets, one of which pops the valve seat between the output port and the input port and the other poppet has the valve seat between the output port and the exhaust port. Open and close. By the push rod driven by the proportional solenoid, one of the poppets is displaced from the closed position where it abuts on the valve seat, and the other poppet stops at the displaced position. Therefore, in the poppet valve, due to friction and sticking of each poppet, push rod, etc., hysteresis is generated and the sensitivity is lowered. Therefore, also in the poppet valve, dither is given to each poppet via the push rod.

[0009]

However, in the method of driving the spool 153 by the pulse exciting current, the pulse voltage applied to the proportional solenoid 151 in order to generate the pulse exciting current according to the displacement position of the spool 153. Pulse width changes. Since the proportional solenoid 151 is an inductive load, if the pulse width of the pulse voltage changes,
The amplitude and waveform of the pulse exciting current flowing through the exciting solenoid 151 changes. As a result, the amplitude of the dither generated by this pulse exciting current changes. If this fluctuation range becomes large, the dither amplitude becomes too large beyond the proper range to generate vibration and noise, or conversely it becomes too small to obtain a high dither effect.

Further, in the method of obtaining the dither by the pulse exciting current, the dither always occurs while the proportional solenoid 151 is driven. When dither is generated by the poppet valve type solenoid proportional control valve in this way, each poppet may repeatedly collide with each valve seat by the dither provided from the push rod when both poppets are in the closed position. become. As a result, the poppet and the valve seat are damaged early, and the valve function is damaged early.

The present invention has been made to solve the above problems, and a first object thereof is an electromagnetic proportional control valve capable of suitably controlling dither according to a displacement position of a valve body. To provide a driving method and an electromagnetic proportional control valve.

A second object of the present invention is to provide a control method of an electromagnetic proportional control valve and an electromagnetic proportional control valve capable of giving a constant dither amplitude to the valve body regardless of the displacement position of the valve body.

A third object of the present invention is to provide a method of controlling an electromagnetic proportional control valve and an electromagnetic proportional control valve capable of preventing dither from being applied to the valve body when the valve body is in the closed position.

[0014]

In order to solve the above problems, the invention according to claim 1 supplies an exciting current corresponding to a target displacement position to an exciting coil for driving a movable iron core for displacing a valve body. In the method of controlling the electromagnetic proportional control valve in which the valve element is displaced to the target displacement position, the dither is applied to the valve element by the first exciting coil that is excited by the pulse exciting current whose frequency and pulse width are set in advance. And a second exciter coil that is provided independently of the first exciting coil and is excited by a valve disc drive current whose magnitude is controlled based on the target displace position, to move the valve disc to the target displace position. It was made to shift to.

According to a second aspect of the present invention, an exciting current corresponding to a target displacement position is supplied to an exciting coil for displacing the valve body to bias the valve body to the closed position and drive the valve body bidirectionally from the closed position. In the control method of the electromagnetic proportional control valve adapted to be displaced to the target displacement position, the valve body is biased to the closed position by the first exciting coil excited by the bias exciting current having a preset magnitude, The first
The second exciting coil, which is provided independently of the exciting coil and is excited by the pulse drive current pulse-modulated according to the target displacement position, displaces the valve body from the closed position to the target displacement position, and I gave dither to my body.

According to a third aspect of the present invention, in an electromagnetic proportional control valve provided with an exciting coil that is excited by an exciting current corresponding to a target displacement position and drives a movable iron core that displaces a valve body, the exciting coil is A first exciting coil and a second exciting coil are provided, and each exciting coil is provided on one side in the displacement direction of the valve body.

According to a fourth aspect of the present invention, in the invention of the third aspect, the first exciting coil and the second exciting coil are arranged side by side on a movable iron core driven by each exciting coil. I decided.

Therefore, according to the first aspect of the present invention,
The valve element is displaced to the target displacement position by the movable iron core driven by the second excitation coil that is excited by the valve element drive current whose size is controlled according to the target displacement position. Then, the movable iron core is driven by the first exciting coil which is excited by a pulse exciting current having a frequency and pulse width different from the valve body driving current, and dither is given to the valve body. Therefore, since the pulse excitation current does not change even if the valve body drive current changes, it is possible to make the dither amplitude constant regardless of the displacement position of the valve body. Since the dither is generated by the pulse excitation current, the dither having a high dither effect can be applied to the valve body.

According to the second aspect of the invention, the movable iron core is driven by the first exciting coil which is excited by the bias exciting current of which the magnitude is set in advance, and the valve body is arranged at the closed position. . Then, the movable iron core is driven by the second exciting coil that is excited by the pulse drive current whose pulse width is modulated based on the target displacement position, and the valve body is displaced from the closed position to the target displacement position and the displacement is performed. Dither is given to the valve body. Therefore, when the valve body is placed in the closed position, the pulse drive current becomes 0, and thus the valve body is not dithered. As a result, the valve body is given dither only when it is displaced from the closed position.

According to the third aspect of the present invention, since two exciting coils for driving the valve body are provided, the first exciting coil is excited by the pulse exciting current having the constant frequency and the constant pulse width, and the valve is excited. It is possible to displace the valve body to the target displacement position by applying dither to the body and exciting the second exciting coil with an exciting current corresponding to the target displacement position. Alternatively, the first excitation coil is excited to dispose the valve element at the closed position, and the second excitation coil is excited by the excitation current that displaces the valve element from the closed position to the target displacement position to move the valve element to the target displacement position. It can be displaced.

Since the two exciting coils are provided on one side in the displacement direction of the valve body, the structure of the electromagnetic proportional control valve is simple as compared with the structure in which one exciting coil is provided on each side of the valve body. It becomes possible to

According to the fourth aspect of the present invention, since the movable iron core is not housed inside each exciting coil, the winding diameter of each exciting coil can be reduced. As a result, the length of the copper wire required for the number of turns to obtain the same magnetomotive force becomes shorter, and the resistance of the exciting coil becomes smaller. Therefore, a large exciting current can be passed through the exciting coil, and the same magnetomotive force can be obtained with a smaller number of turns.

Further, since the exciting coil is provided on the side of the movable iron core, flattening is possible. Further, since the impedance is reduced due to the reduction in the number of turns, the exciting current rises quickly, and a large attractive force can be generated. As a result, the valve body can be driven at high speed, and the responsiveness can be improved.

Furthermore, since the amount of copper wire used is reduced, the material cost can be reduced and the weight of the electromagnetic proportional control valve can be reduced. Further, since the magnetic circuit that supplies the magnetic flux from each exciting coil to the movable iron core can be formed of a magnetic material having a simple shape, the workability of the magnetic circuit is improved, and the restrictions on the processing due to the shape are reduced. Therefore, it is possible to use a magnetic material that has excellent magnetic properties but cannot be used because of poor workability. As a result, the electromagnetic proportional control valve can be further downsized and the responsiveness can be improved.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] A first embodiment in which the present invention is embodied in a pressure control device for controlling air pressure will now be described with reference to FIG.
3 will be described with reference to FIG.

As shown in FIG. 2, the pressure control device 1 includes an electromagnetic proportional control valve 2, a filter 3, an oil mist separator 4, an electromagnetic valve driving device 5, a deviation amplifier 6 and a pressure detector 7.
It consists of. The electromagnetic proportional control valve 2 is functionally shown as a 3-port 3-position valve. A control signal generator 8 for outputting a target pressure signal VS is connected to the pressure control device 1. The target pressure signal VS is a pressure (hereinafter, referred to as an actual pressure) P that the pressure control device 1 supplies to the load L.
This is a signal for setting O 2, and is generated based on a pressure command signal from an external control computer (not shown).

Air of pressure PI is supplied to the filter 3 from an air pressure source S. The filter 3 supplies to the oil mist separator 4 air obtained by removing water from the air supplied from the air pressure source S. The oil mist separator 4 supplies the electromagnetic proportional control valve 2 with air obtained by removing oil mist from the air supplied from the filter 3.

The pressure detector 7 is an actual pressure signal VO which is a detected value of the actual pressure PO supplied by the electromagnetic proportional control valve 2 to the load L.
Is output to the deviation amplifier 6. The deviation amplifier 6 amplifies the deviation of the actual pressure signal VO from the target pressure signal VS and outputs the signal as a control deviation signal ΔV to the solenoid valve driving device 5. The control deviation signal ΔV is a signal for controlling the valve opening of the electromagnetic proportional control valve 2 to the target valve opening.

Next, the structure of the electromagnetic proportional control valve 2 will be described in detail. As shown in FIG. 1, the solenoid proportional control valve 2 includes a valve portion 10
And a drive unit 11. An input port 13, an output port 14, and an exhaust port 15 are arranged in parallel on the valve body 12 of the valve portion 10 from the right side. Valve body 12
The sleeve 16 is inserted into the hole formed inside the
A spool chamber 17 is formed inside the sleeve 16. The spool chamber 17 is in communication with an input port 13, an output port 14, and an exhaust port 15. In the spool chamber 17, a spool 18 that switches and communicates the input port 13 or the exhaust port 15 with the output port 14 is provided. That is, when the spool 18 is arranged at the closed position in the center of the spool chamber 17, the output port 14 is not connected to either the input port 13 or the exhaust port 15. When the spool 18 is displaced leftward from the closed position, the input port 13 is communicated with the output port 14 with a flow passage cross-sectional area corresponding to the displacement amount. On the contrary, when the spool 18 is displaced rightward from the closed position, the exhaust port 15 is communicated with the output port 14 with a flow passage cross-sectional area corresponding to the displacement amount. A spring chamber 19 is formed at the left end of the spool chamber 17, and a compression coil spring 20 that is in contact with the left end surface of the spool 18 and constantly biases the spool 18 to the right is disposed in the spring chamber 19. The valve body 12 is provided with a port 21 that opens the spring chamber 18 to the atmosphere.

An iron core chamber 22 communicating with the spool chamber 17 is formed inside the drive unit 11. A movable iron core 23 is arranged in the iron core chamber 22, and a sliding shaft 24 for driving the spool 18 is penetratingly fixed to the movable iron core 23. The sliding shaft 2 made of a magnetic material is provided at the left end of the iron core chamber 22.
A support portion 25 that surrounds and supports the left end of 4 is provided, and a bearing 26 that is in sliding contact with the outer periphery of the left end portion of the sliding shaft 24 is fixed to the inner periphery of the support portion 25. At the right end of the iron core chamber 22, there is provided a support portion 27 made of a non-magnetic material and surrounding and supporting the right end of the sliding shaft 24. The inner periphery of the supporting portion 27 is provided at the outer periphery of the right end portion of the sliding shaft 24. A bearing 28 that is in sliding contact is fixed.

A cylindrical magnetic path 29 for guiding a magnetic flux to the movable iron core 23 is arranged on the outer peripheral side of the iron core chamber 22. On the outer peripheral side of the magnetic path 29 and the support portion 25, an exciting coil portion 30 which is formed in an annular shape and supplies magnetic flux to the magnetic path 29 and the support portion 25 is arranged. The exciting coil portion 30 includes an outer cylinder portion 31 made of a magnetic material, and a first exciting coil 32 is arranged on the right side of the inner peripheral side of the outer cylinder portion 31 (that is, the opposite side of the valve portion 10). Similarly on the left side (that is, on the valve section 10 side)
A second exciting coil 33 is arranged in the. Outer tube part 3
The right inner peripheral surface of 1 is in contact with the outer peripheral surface of the magnetic path 29, and the left inner peripheral surface of the outer tubular portion 31 is in contact with the outer peripheral surface of the support portion 25. A magnetic circuit for supplying magnetic flux to the movable iron core 23 is configured by the outer cylinder portion 31, the magnetic path 29, and the support portion 25.

The first exciting coil 32 and the second exciting coil 33 are formed with the same number of turns. The magnetic flux generated by the first exciting coil 32 or the second exciting coil 33 acts on the movable iron core 23 in the magnetic circuit.

Next, the structure of the solenoid valve driving device 5 will be described in detail. As shown in FIG. 3, the solenoid valve driving device 5 is composed of a first driving unit 40 and a second driving unit 41.
The first drive section 40 includes a bias setting section 42, a first operational amplifier 43, a first frequency setting section 44, a first function generating section 45, a first PWM control section 46, and a first output circuit 47.
And a resistor 48, which is a known constant current circuit by pulse width modulation.

The bias setting section 42 has a variable resistance and generates a bias setting signal VB from a predetermined voltage VC. The bias setting signal VB is a signal for setting the displacement position where the spool 18 is biased.

The first operational amplifier 43 receives the bias setting signal VB and the first detection voltage VK1 which will be described later, and inputs the bias setting signal VB and the first detection voltage VK1.
Is added to the bias setting signal VB, and the signal is used as the first control signal VR1 for the first PWM control unit 4
6 is output.

The first frequency setting section 44 has a variable resistor, and generates a first frequency setting signal IF1 from a predetermined voltage VC and outputs it to the first function generator 45. The first frequency setting signal IF1 is a signal for setting the frequency of the dither given to the spool 18. The first function generator 45 generates the first reference signal (triangular wave) VT1 having the frequency set by the first frequency setting signal IF1 to generate the first PW.
It is output to the M control unit 46.

The first PWM control section 46 receives the first reference voltage V1 by the first control signal VR1 and the first reference signal VT1.
The first control operation signal VA1 having a carrier frequency of T1 and having a pulse width (duty ratio) proportional to the first control signal VR1 is output to the first output circuit 47. Therefore, the first control operation signal VA1 has a smaller pulse width as the first control signal VR1 becomes smaller, and has a larger pulse width as the first control signal VR1 becomes larger.

A positive power supply voltage + V is applied to the first output circuit 47.
C is connected. The first output circuit 47 outputs a positive bias exciting current IB as a pulse exciting current to the first exciting coil 32 based on the first control operation signal VA1. The bias exciting current IB is a signal for biasing the spool 18 to the closed position and generating dither on the spool 18.

The bias exciting current IB output from the first output circuit 47 flows through the resistor 48 and is generated by the first output circuit 47.
The detected voltage VK1 is output to the first operational amplifier 43. The first detection voltage VK1 is a signal for feeding back the actual bias exciting current IB, which is a controlled variable, to the bias setting signal VB, which is a target value, and performing feedback control of the bias exciting current IB.

The second drive section 41 includes a gain adjusting section 5
0, the second operational amplifier 51, the second frequency setting unit 52,
Second function generator 53, second PWM control unit 54, second
It is a constant current circuit based on the well-known pulse width modulation, which is composed of the output circuit 55 of FIG.

The gain adjusting section 50 generates the position control signal VP1 from the control deviation signal ΔV output from the deviation amplifier 6. This position control signal VP1 sets the spool 1 to the displacement position corresponding to the control deviation signal ΔV with the closed position as 0 point.
8 is a signal for controlling 8.

The second operational amplifier 51 has a position control signal V
A second detection voltage VK2, which will be described later, is input together with P1 and a deviation between the position control signal VP1 and the second detection voltage VK2 is added to the position control signal VP1 and the signal is amplified to produce a second signal.
Is output to the second PWM controller 54 as the control signal VR2.

On the other hand, the second frequency setting section 52 generates the second frequency setting signal IF2 from the predetermined voltage VC and outputs it to the second function generator 53. The second frequency setting signal IF2 is a signal for setting a frequency sufficiently higher than the frequency at which dither is generated. The second function generator 53 generates the second reference signal (triangular wave) VT2 having the frequency set by the second frequency setting signal IF2 to generate the second PW.
It is output to the M control unit 54.

The second PWM control section 54 uses the second control signal VR2 and the second reference signal VT2 to generate the second control signal V
When R2 is positive, a second control operation signal VA2 having a carrier frequency of the second reference signal VT2 and a positive pulse signal having a pulse width (duty ratio) proportional to the second control signal VR2 is generated. Output to the second output circuit 55. Therefore, the second
Control operation signal VA2 has a smaller duty ratio as the second control signal VR2 becomes smaller, and the second control signal VR2
Is a positive pulse signal with a larger duty ratio as becomes larger.

Further, the second PWM control section 54 uses the second control signal VR2 and the second reference signal VT2 to generate the carrier frequency of the second reference signal VT2 when the second control signal VR2 is negative. And outputs a second control operation signal VA2 composed of a negative pulse signal having a pulse width (duty ratio) proportional to the second control signal VR2 to the second output circuit 55. Therefore,
The second control operation signal VA2 is a negative pulse signal having a smaller duty ratio as the second control signal VR2 becomes smaller and a larger duty ratio as the second control signal VR2 becomes larger.

The second output circuit 55 has a positive power supply voltage +
VC and the negative power supply voltage -VC are connected. The second output circuit 55 outputs a spool drive current ID1 as a valve drive current composed of a positive or negative pulse current to the second exciting coil 33 based on the second control operation signal VA2. That is, the spool drive current ID1 is the second control operation signal VA2.
Is a positive pulse signal, and is a negative pulse signal when the second control operation signal VA2 is a negative pulse signal. The spool drive current ID1 is a signal for exciting the second exciting coil 33 to drive the spool 18 to a displacement position (that is, a target displacement position) corresponding to the control deviation signal ΔV with the closed position being 0 point. .

Further, the spool drive current ID1 output from the second output circuit 55 flows through the resistor 56 and is generated by the second output circuit 55.
Of the detected voltage VK2 is output to the second operational amplifier 51. The second detection voltage VK2 is a signal for feeding back the actual spool drive current ID1 which is a control amount to the position control signal VP1 which is a target value and feedback-controlling the spool drive current ID1.

Next, the operation of the pressure control device and the electromagnetic proportional control valve configured as described above will be described. After the load L is connected to the solenoid proportional control valve 2, the solenoid valve driving device 5
Is activated, the first drive section 40 outputs a bias exciting current IB corresponding to the bias setting signal VB to the first exciting coil 32. At this time, in the first drive unit 40,
Since the bias exciting current IB is feedback-controlled to a value corresponding to the bias setting signal VB, the highly accurate bias exciting current IB is supplied to the first exciting coil 32. The bias exciting current IB becomes a signal whose frequency and pulse width are constant. As a result, the spool 18 is
The excitation coil 32 drives and holds it to the closed position with high accuracy. At the same time, the spool 18 is dithered by the first exciting coil 32 which is excited by the bias exciting current IB. At this time, the spool 18
When the spool 1 is out of the closed position, the bias setting signal VB is adjusted by the bias setting section 42 to adjust the spool 1
Bias 8 to the closed position.

From the control signal generator 8, the target pressure signal VS
Is output, the deviation amplifier 6 outputs a control deviation signal .DELTA.V, which is an amplified deviation between the target pressure signal VS and the actual pressure signal VO, to the second drive section 41. The second drive unit 41 outputs the spool drive current ID1 corresponding to the control deviation signal ΔV to the second exciting coil 33. At this time, the second drive unit 41
Then, since the spool drive current ID1 is feedback-controlled to the value corresponding to the position control signal VP1 corresponding to the control deviation signal ΔV, the spool drive current ID1 with high accuracy is supplied to the second exciting coil 33. As a result, the spool 18 is driven by the second exciting coil 33 with high accuracy from the closed position to the displacement position corresponding to the position control signal VP1. Since the frequency of the spool drive current ID1 is set to a frequency sufficiently higher than the frequency at which dither is generated, the spool drive current ID1 causes the spool 1
No dither is given to 8.

At this time, the control deviation signal ΔV given as the target valve opening degree of the electromagnetic proportional control valve 2 gradually decreases when air is supplied to the load L and the actual pressure VO rises.
When the actual pressure VO reaches the target pressure, the control deviation signal Δ
Since V becomes zero, the spool 18 is arranged at the closed position so that the valve opening becomes zero. In this way, the actual pressure Vo of the air supplied to the load L is controlled to the pressure corresponding to the target pressure signal VS.

Since the bias exciting current IB is constantly supplied to the first exciting coil 32, dither is applied to the spool 18 regardless of its displacement position. Since this bias exciting current IB is generated independently of the spool drive current ID1, even if the average current value of the spool drive current ID1, that is, the pulse width changes in accordance with the control deviation signal ΔV,
The pulse width and the waveform of the bias exciting current IB never change. As a result, the spool 18 is given dither with a constant amplitude regardless of its displacement position.

As described in detail above, according to the electromagnetic proportional control valve of the present embodiment, the following effects can be obtained. (A) The first drive unit 40 generates a bias exciting current IB, which is a pulse signal for generating dither in the spool 18 and has a constant frequency and pulse width, and the first exciting coil 32 is generated by the bias exciting current IB. To bias the spool 18 to the closed position. On the other hand, the second drive unit 41 generates the spool drive current ID1 for driving the spool 18 to the displacement position corresponding to the control deviation signal ΔV, and the spool drive current ID1 is used to generate the second excitation coil 3
3 is excited to drive the spool 18 biased to the closed position to the displaced position. Therefore, the bias excitation current IB
Is generated independently of the spool drive current ID1,
Even if the spool drive current ID1 changes, its pulse width and waveform become constant. As a result, it is possible to obtain a dither with a constant amplitude that can obtain a high dither effect regardless of the displacement position of the spool 18. Therefore, since the hysteresis of the electromagnetic proportional control valve 2 can be canceled, the spool 18 can be controlled with high accuracy to control the target displacement position (that is, the valve opening) of the spool 18, and the sensitivity can be improved. Can be higher.

Further, when the pressure control device 1 is constructed, the actual pressure VO can be controlled to the target pressure with high accuracy and the sensitivity can be increased. Further, since the first exciting coil 32 and the second exciting coil 33 jointly displace the spool 18 to the target displacement position, comparison with the conventional case where the spool 18 is driven by only one exciting coil Then, each exciting coil can be downsized. Therefore, the impedances of the exciting coils 32 and 33 are reduced, and the spool drive current ID1 rises faster, so that the responsiveness of the spool 18 can be improved.

(B) Since the first exciting coil 32 and the second exciting coil 33 are provided on one side of the displacement direction of the spool 18, one exciting coil is provided on each side of the spool 18 in the displacing direction. Compared to the structure provided,
The structure of the electromagnetic proportional control valve 2 can be simplified.

(C) The spool drive current ID1 is generated by the second drive section 41 which is a pulse generation circuit having the same configuration as the first drive section 40. At this time, the frequency of the spool drive current ID1 is set sufficiently higher than the frequency of the bias excitation current IB that generates dither so that the spool drive current ID1 does not generate dither. Therefore, the second drive unit 41 can be configured by a pulse generation circuit having the same configuration as the first drive unit 40, and therefore, the spool drive current ID1 is simpler than a circuit configuration that is generated by a DC current. It is possible to have various circuit configurations.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the exciting coil portion 30 of the electromagnetic proportional control valve 2 in the first embodiment is replaced with the exciting coil portion 6.
Replaced with 0. Further, the first drive unit 40 in the first embodiment is the first drive unit 70, and the second drive unit 41 is the second drive unit 71. The above points are the points different from the first embodiment.

First, the structure of the electromagnetic proportional control valve 2 will be described. On the outer peripheral side of the support portion 25 and the magnetic path 29, an exciting coil portion 60 which is formed in an annular shape and supplies magnetic flux to the magnetic path 29 and the support portion 25 is arranged. The exciting coil portion 60 includes an outer cylinder portion 31 made of a magnetic material, a first exciting coil 61 is arranged on the right side on the inner peripheral side of the outer cylinder portion 31, and a second exciting coil 62 is also arranged on the left side. Is provided.

The number of turns of the second exciting coil 62 is substantially the same as that of the exciting coil of the conventional electromagnetic proportional control valve.
The number of turns of the first exciting coil 61 is equal to that of the second exciting coil 62.
The number of turns is less than the number of turns.

Next, the structure of the solenoid valve driving device 5 will be described. As shown in FIG. 5, the solenoid valve drive device 5 is composed of a first drive unit 70 and a second drive unit 71.
The first drive unit 70 includes a pulse width setting unit 72, a first operational amplifier 73, a first frequency setting unit 74, a first function generating unit 75, a first PWM control unit 76, a first output circuit. 77
And a resistor 78, which is a known constant current circuit by pulse width modulation.

The pulse width setting section 72 has a variable resistance, and generates a pulse width setting signal VW from a predetermined voltage + VC and outputs it to the first operational amplifier 73. The pulse width setting signal VW is a signal for setting the amplitude of dither given to the spool 18.

The first operational amplifier 73 receives the pulse width setting signal VW and receives a third detection voltage VK3 which will be described later.
Input pulse width setting signal VW and third detection voltage VK3
The deviation between and is added to the pulse width setting signal VW, and the signal is output to the first PWM control unit 76 as the third control signal VR3.

On the other hand, the first frequency setting section 74 generates a third frequency setting signal IF3 from a predetermined voltage + VC and outputs it to the first function generator 75. The third frequency setting signal IF3 is a signal for setting the dither frequency. The first function generator 75 generates a third reference signal VT3 having a frequency set by the third frequency setting signal IF3, and outputs it to the first PWM control unit 76.

The first PWM control section 76 has a pulse having a carrier frequency of the third reference signal VT3 and a pulse proportional to the third control signal VR3 according to the third control signal VR3 and the third reference signal VT3. The third control operation signal VA3, which is a pulse signal having a width (duty ratio), is output to the first output circuit 77. Therefore, the third control operation signal VA3 has a smaller pulse width as the third control signal VR3 becomes smaller, and has a larger pulse width as the third control signal VR3 becomes larger.

The first output circuit 77 has a positive power supply voltage +
VC is being applied. The first output circuit 77 outputs a dither current IDT as a pulse exciting current composed of a positive pulse signal to the first exciting coil 61 based on the third control operation signal VA3. The dither current IDT is a signal for applying dither to the spool 18. The spool 18 is biased by the average current of the dither current IDT.
Offset by an initial bias of 0. That is, in the compression coil spring 20 of the present embodiment, the initial biasing force is set to be larger than that of the compression coil spring of the first embodiment by the bias amount.

Further, the dither current IDT output by the first output circuit 77 flows through the resistor 78, and the generated third detection voltage VK3 is output to the first operational amplifier 72.
The first detection voltage VK3 is a signal for feeding back the dither current IDT which is a control amount to the pulse width setting signal VW which is a target value.

The second drive section 71 includes a gain adjusting section 8
0, bias setting unit 80A, adder 80B, second operational amplifier 81, second frequency setting unit 82, second function generator 83, second PWM control unit 84, second output circuit 85.
And a resistor 86, which is a known constant current circuit by pulse width modulation.

The gain adjusting section 80 has a variable resistor, and gain-adjusts the control deviation signal ΔV output from the deviation amplifier 6 and outputs it to the adder 80B. Bias setting unit 80A
Generates a bias signal VB from a predetermined voltage + VC and outputs it to the adder 80B. The bias signal VB is a signal for placing the spool 18 in the closed position. The adder 80B adds the gain-adjusted control deviation signal ΔV to the bias signal, and outputs this signal to the second deviation amplifier 81 as the position control signal VP2. This position control signal VP2 is a control deviation signal ΔV from the closed position of the spool 18.
Is a signal for controlling the displacement position corresponding to (i.e., the target displacement position from the closed position).

The second operational amplifier 81 has a position control signal V
A second detection voltage VK4, which will be described later, is input together with P2, and the deviation between the position control signal VP2 and the second detection voltage VK4 is added to the position control signal VP2, and the second PWM control unit 84
Output to

On the other hand, the second frequency setting section 82 generates the fourth frequency setting signal VF4 from the predetermined voltage + VC and outputs it to the second function generator 83. The fourth frequency setting signal VF4 is a signal for setting a frequency sufficiently higher than the third frequency setting signal VF3 for generating dither. The second function generator 83 generates a fourth reference signal VT4 having a frequency set by the fourth frequency setting signal VF4 and outputs the fourth reference signal VT4 to the second PWM control unit 84.

The second PWM control unit 84 has a carrier frequency of the fourth reference signal VT4 and a pulse proportional to the fourth control signal VR4, according to the fourth control signal VR4 and the fourth reference signal VT4. The fourth control operation signal VA4, which is a pulse signal having a width (duty ratio), is output to the second output circuit 85. Therefore, the fourth control operation signal VA4 has a smaller pulse width as the fourth control signal VR4 becomes smaller, and has a larger pulse width as the fourth control operation signal VR4 becomes larger.

A positive power supply voltage + V is applied to the second output circuit 85.
C is applied. The second output circuit 85 outputs the spool drive current ID2 as the valve body drive current to the second exciting coil 62 based on the fourth control operation signal VA4. This spool drive current ID2 corresponds to a value obtained by adding the bias signal VB to the control deviation signal ΔV from the position of the spool 18 when the second exciting coil 62 is not excited and the movable iron core 23 is not displaced. Spool 18 at the displacement position
Is a signal for directly driving.

The spool drive current ID2 output from the second output circuit 85 flows through the resistor, and the generated fourth detection voltage VK4 is output to the second operational amplifier 81. This fourth detection voltage VK4 is a position control signal VP2 which is a target value.
Is a signal for feeding back the deviation of the spool drive current ID2 which is a control amount.

Next, the operation of the pressure control device and the electromagnetic proportional control valve configured as described above will be described. When the solenoid valve driving device 5 is operated, the first driving unit 70 outputs the dither current IDT to the first exciting coil 61. At this time, in the first drive unit 70, the dither current IDT is feedback-controlled to a value corresponding to the pulse width setting signal VW, so that the highly accurate dither current IDT is supplied to the first exciting coil 61. The dither current IDT becomes a signal whose frequency and pulse width are constant. As a result, the dither having a constant amplitude with high accuracy is given to the spool 18. When the spool drive current ID2 based on the bias signal VB is output from the drive unit 71 to the second exciting coil 62,
The spool 18 is controlled to the closed position. When the target pressure signal VS is output from the control signal generator 8 in this state, the deviation amplifier 6 outputs the control deviation signal ΔV to the second drive unit 7.
Output to 1. The second drive unit 71 controls the control deviation signal ΔV.
The spool drive current ID2 based on the position control signal VP2 obtained by adding the bias signal VB to the second exciting coil 62 is output. At this time, in the second drive section 71, the spool drive current ID2 is feedback-controlled to a value corresponding to the position control signal VP2 generated by adding the bias signal VB to the control deviation signal ΔV, so that the accuracy is high. The spool drive current ID2 is output to the second exciting coil 62. As a result, the spool 18 is driven with high accuracy by the second exciting coil 62 to the displacement position corresponding to the position control signal VP2. That is, the displacement position corresponding to the control deviation signal ΔV which is the target displacement signal from the closed position is controlled with high accuracy.

At this time, the control deviation signal ΔV given as the target valve opening degree of the electromagnetic proportional control valve 2 gradually decreases when the air is supplied to the load L and the actual pressure VO rises.
When the actual pressure VO reaches the target pressure, the control deviation signal Δ
Since V becomes zero, the spool 18 is arranged at the closed position so that the valve opening becomes zero. In this way, the actual pressure Vo of the air supplied to the load L is controlled to the pressure corresponding to the target pressure signal VS.

Since the dither current IDT is constantly supplied to the first exciting coil 61, dither is applied regardless of the displacement position of the spool 18. Since this dither current IDT is generated independently of the spool drive current ID2, even if the average current value of the spool drive current ID2, that is, the pulse width changes according to the control deviation signal ΔV, the dither current IDT is changed.
Does not change the pulse width and waveform. as a result,
The spool 18 is provided with dither having a constant amplitude regardless of its displacement position.

As described in detail above, according to the electromagnetic proportional control valve of the present embodiment, the following effects can be obtained. (A) The first drive unit 70 generates a dither current IDT composed of a pulse signal for giving dither to the spool 18 having a constant frequency and pulse width, and the first excitation coil is generated with this dither current IDT. 61 was excited to give the spool 18 dither. On the other hand, the second drive unit 71 generates a spool drive current ID2 for driving the spool 18 to each displacement position, and the spool drive current ID2 excites the second exciting coil 62 to spool 1
8 is driven to the displacement position corresponding to the control deviation signal ΔV. Therefore, since the dither current IDT is generated independently of the spool drive current ID2, the pulse width and waveform of the dither current IDT are constant even if the spool drive current ID2 changes. As a result, even in the present embodiment,
Similar to the first embodiment, since it is possible to generate a dither with a constant amplitude that can obtain a high dither effect regardless of the displacement position of the spool 18, the spool 18 can be controlled with high accuracy and the target displacement position (one The opening degree) can be controlled.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. The electromagnetic proportional control valve according to the present embodiment is the valve portion (spool valve) of the electromagnetic proportional control valve 2 according to the first embodiment.
The difference from the first embodiment is that 10 is changed to a valve portion (poppet valve) 90. Further, in the solenoid valve drive system 5 of the first embodiment, the first frequency setting unit 44 outputs.
A second frequency setting signal IF1 for setting the frequency of the bias exciting current IB is output by the second frequency setting section 52 of the present embodiment, and a second frequency setting signal IF3 for setting the frequency of the poppet drive current ID3 is output. It was replaced with the frequency setting signal IF2. On the contrary, in the first embodiment, the second frequency setting signal IF2 for setting the frequency of the spool drive current ID is used as the first frequency for setting the frequency of the bias exciting current IB of the present embodiment. Replaced with the setting signal IF1. The above points are the points different from the first embodiment. Therefore, only the valve portion 90, the bias excitation current IB generated by the first drive unit 40, and the poppet drive current ID3 generated by the second drive unit 41 will be described in detail, and the first embodiment will be described. The same components as those in the embodiment have the same reference numerals and the description thereof will be omitted.

First, the structure of the valve portion will be described. As shown in FIG. 6, an output port 92 is formed on one side of the valve body 91 of the valve portion 90, and an input port 93 and an exhaust port 94 are provided on the other side. A communication hole 95 that connects the output port 92, the input port 93, and the exhaust port 94 is formed inside the valve body 91. Inside the communication hole 95, a valve seat 96 is formed between the input port 93 and the output port 92, and a valve seat 97 is also formed between the exhaust port 94 and the output port 92.

A poppet holder 98 is provided at the left end of the communication hole 95.
The poppet holder 98 accommodates a poppet 99 as a valve body for opening and closing the valve seat 97.
Inside the poppet holder 98, an urging spring 100 that urges the poppet 99 to a position where the opening / closing surface 99a of the poppet 99 contacts the valve seat 97 (hereinafter referred to as a closing position) is housed. Further, the poppet holder 1 is provided at the right end of the communication hole 95.
01 is arranged, and the poppet holder 101 has a valve seat 9
A poppet 102 as a valve body for opening and closing 6 is accommodated. Inside the poppet holder 101, the poppet 1
A biasing spring 103 that biases the poppet 102 is housed in a position (hereinafter, referred to as a closing position) where the opening / closing surface 102 a of 02 contacts the valve seat 96.

A push rod 104 for displacing the poppet 99 leftward from the closed position or displacing the poppet 102 rightward from the closed position is disposed between the poppet 99 and the poppet 102. ing. Inside the poppet holder 98, the push rod 10
A return spring 105 that contacts the left end of the push rod 4 and biases the push rod 104 to the right is housed. The left end of the sliding shaft 24 that drives the push rod 104 to the left is in contact with the right end of the push rod 104.

Next, the solenoid valve drive device will be described.
As shown in FIG. 3, the first frequency setting unit 44 generates the first frequency setting signal IF1 and outputs it to the first function generator 45. This first frequency setting signal IF1 is used for the poppet 1
It is a signal for setting a frequency sufficiently higher than the frequency of the dither generated in 8. First output circuit 47
Outputs a bias exciting current IB, the frequency of which is set by the first frequency setting signal IF1, to the first exciting coil 32. This bias exciting current IB is applied to the push rod 104.
Is a signal for causing both poppets 99 and 102 to be placed in their respective closed positions by biasing them to a predetermined position.

The second frequency setting section 52 generates the second frequency setting signal IF2 and outputs it to the second function generator 53. The second frequency setting signal IF2 is a signal for setting the frequency of the dither generated in the poppet 18. The second output circuit 55 outputs the second frequency setting signal IF2
The poppet drive current ID3 as the pulse drive current whose frequency is set at is output to the second exciting coil 33. The poppet drive current ID3 drives the poppets 99 and 102 to the displacement position (that is, the target displacement position) corresponding to the control deviation signal ΔV by the second exciting coil 33 with each closed position as 0 point. It is a signal for giving dither to the poppets 99 and 102.

Next, the operation of the pressure control device and the electromagnetic proportional control valve configured as described above will be described. When the solenoid valve driving device 5 is operated, the first driving section 40 outputs the bias exciting current IB to the first exciting coil 32. At this time, the highly accurate bias exciting current IB is supplied from the first driving section 40 to the first exciting coil 32. The bias exciting current IB has a constant magnitude.
As a result, the push rod 104 is driven with high accuracy, and the poppets 99 and 104 are arranged in the respective closed positions with high accuracy. At this time, since the frequency of the bias exciting current IB is set to a frequency sufficiently higher than the frequency at which dither is generated, the dither is not given to the poppets 99 and 104 by the bias exciting current IB. .

From the control signal generator 8, the target pressure signal VS
Is output, the deviation amplifier 6 outputs the control deviation signal ΔV to the second driver 41. The second drive unit 41 outputs the poppet drive current ID3 based on the control deviation signal ΔV to the second excitation coil 33. At this time, the second drive unit 41
From, a highly accurate poppet drive current ID3 is output to the second exciting coil 33. As a result, since the push rod 104 is driven with high accuracy by the second excitation coil 33, the poppet 99 or the poppet 102 is driven with high accuracy from each closed position to the displacement position corresponding to the position control signal VP.

At this time, the control deviation signal ΔV given as the target valve opening degree of the electromagnetic proportional control valve 2 gradually decreases when air is supplied to the load L and the actual pressure VO rises.
When the actual pressure VO reaches the target pressure, the control deviation signal Δ
Since V becomes zero, the poppets 99 and 102 are arranged at the closed positions so that the valve opening becomes zero. In this way, the actual pressure Vo of the air supplied to the load L is controlled to the pressure corresponding to the target pressure signal VS.

When the poppet drive signal ID3 is supplied to the second exciting coil 33, the poppet 99, 10 which is displaced from its closed position by the push rod 104.
Dither is given to 2. That is, since the poppets 99 and 102 which are stopped at the closed position are not driven by the push rod 104, dither is not given.
Therefore, the poppet 99 in the closed position does not collide with the valve seat 97, and the poppet 102 in the closed position does not collide with the valve seat 96.

When the poppet drive signal IDP becomes 0, that is, when both poppets 99 and 102 are arranged in the closed position, no dither is applied to the push rod 104 from the second exciting coil 33, so that the poppets are not populated. No dither is given to 99 and 102. Therefore, when both the poppets 99 and 102 are arranged in the closed position, the poppet 99 does not collide with the valve seat 97 by the dither and the poppet 102 does not collide with the valve seat 96.

In the present embodiment, unlike the first embodiment, dither is generated by the poppet drive signal ID3 which is a pulse signal for driving the poppets 99 and 102 according to the control deviation signal ΔV. To be done. Therefore, the dither amplitude changes according to the average current of the poppet drive signal ID3, that is, the pulse width.

As described in detail above, according to the electromagnetic proportional control valve of the present embodiment, the following effects can be obtained. (A) A bias exciting current IB having a constant magnitude is generated in the first drive unit 40, and the first exciting coil 32 is excited by the bias exciting current IB to push the push rod 104.
And both poppets 99 and 102 are placed in their respective closed positions. Further, the second drive unit 41 generates a poppet drive current ID3 which is a pulse signal for driving each poppet 99, 102 to the displacement position corresponding to the control deviation signal ΔV, and the poppet drive current ID3 is used to generate the poppet drive current ID3. One of the poppets 9 is excited by exciting the second exciting coil 33.
The dither is applied while driving 9, 102 to the displacement position. As a result, the poppet drive signal ID3 becomes 0,
When both poppets 99 and 102 are arranged at the respective closed positions, no dither is applied to each of the poppets 99 and 102, so that the poppets 99 and 102 may repeatedly collide with the valve seats 96 and 97. Disappear. Therefore, the poppet 99, 102 or the valve seat 96, 9 due to the collision
Since the early damage of 7 can be prevented, the early deterioration of the valve function can be prevented.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIGS. The electromagnetic proportional control valve according to the present embodiment is different from the first embodiment only in that the valve portion 10 is replaced with the valve portion 110 and the exciting coil portion 30 is replaced with the exciting coil portions 122 and 125. This is different from the first embodiment. Therefore, only the valve portion 110 and the exciting coil portions 122 and 125 will be described in detail, and the same components as those in the first embodiment will be designated by the same reference numerals and the description thereof will be omitted.

First, the structure of the valve section 110 will be described in detail. FIG.
As shown in FIG. 3, the valve body 111 of the valve portion 110 has an output port 112 formed on one side and an input port 1 on the other side.
13 and an exhaust port 114 are formed. Valve body 1
A sleeve 115 is fitted in a hole formed inside 11, and a spool chamber 116 is formed inside the sleeve 115. In this spool chamber 116, each port 1
12, 113 and 114 are in communication with each other. In the spool chamber 116, a spool 117 for switching and communicating the input port 113 or the exhaust port 114 with the output port 112 is provided. That is, when the spool 117 is arranged in the closed position in the center of the spool chamber 116, the output port 112 is set to the input port 113 and the exhaust port 11.
It is not connected to any of the four. When the spool 117 is displaced leftward from the closed position, the input port 112 is communicated with the output port 113 with a flow passage sectional area corresponding to the displacement amount. On the contrary, when the spool 117 is displaced rightward from the closed position, the exhaust port 1 has a flow passage sectional area corresponding to the displacement amount.
12 communicates with the exhaust 114. A spring chamber 118 is formed at the right end of the spool chamber 116, and a compression coil spring 119 that contacts the left end of the spool 117 and constantly biases the spool 117 to the right is disposed in the spring chamber 118.

Next, the structure of the exciting coil sections 120 and 125 will be described in detail. As shown in FIGS. 7 and 8, in the drive unit 11, the first excitation coil unit 120 is arranged above the magnetic path 29 and the support unit 25. First coil portion 12
Reference numeral 0 denotes a cylindrical magnetic core 12 arranged on the side of the movable iron core 23.
1, the magnetic core 121 is equipped with a cylindrical first exciting coil 122. Plate-shaped magnetic paths 123 and 124 are connected to both ends of the magnetic core 121, respectively. The magnetic path 123 is brought into contact with the outer peripheral surface of the support portion 25, and the magnetic path 124
Is in contact with the outer peripheral surface of the magnetic path 29. The magnetic core 121, the magnetic paths 29, 123 and 124, and the support portion 25 constitute a magnetic circuit for guiding the magnetic flux generated by the first exciting coil 122 to the movable iron core 23.

A second exciting coil portion 125 is arranged below the magnetic path 29 and the support portion 25. The second exciting coil portion 125 includes a cylindrical magnetic core 126 disposed on the side of the movable iron core 23, and a cylindrical second exciting coil 127 is attached to the magnetic core 126. Plate-shaped magnetic paths 123 and 124 are connected to both ends of the magnetic core 126, respectively. The magnetic path 123 is in contact with the outer peripheral surface of the support portion 25, and the magnetic path 124 is in contact with the outer peripheral surface of the magnetic path 29. Magnetic core 1
26, the magnetic paths 29, 123, 124 and the support portion 25,
The magnetic flux generated by the second excitation coil 127 is transferred to the movable iron core 23.
A magnetic circuit for guiding to is constructed.

Next, the operation of the electromagnetic proportional control valve configured as described above will be described. When the bias exciting current IB is output from the first drive unit 40 to the first exciting coil 122, the spool 18 is biased to the closed position. Dither is applied to the spool 18 by the bias exciting current IB. Further, when the spool drive current ID1 is output from the second drive unit 41 to the second exciting coil 127, the spool 18 is driven from the closed position to the displacement position corresponding to the control deviation signal ΔV. Therefore, as in the first embodiment, the spool 18 is provided with a dither with a constant amplitude that provides a high dither effect regardless of the displacement position of the spool 18.

As described in detail above, according to the electromagnetic proportional control valve of the present embodiment, the following effects can be obtained in addition to the effects of the first embodiment. (A) The support portion 25 and the magnetic path 2 are provided on the side of the movable iron core 23.
9, magnetic cores 121 and 126 magnetically connected to each other are provided, a first exciting coil 122 is arranged around the magnetic core 121, and a second exciting coil 127 is arranged around the magnetic core 126. In other words, each exciting coil 122, 127 is
5 and the magnetic paths 29 instead of being magnetized directly, each core 12
1,126 was magnetized. Therefore, since it is not necessary to house the movable iron core 23 inside each of the exciting coils 122 and 127, the winding diameter of each of the exciting coils 122 and 127 can be reduced. As a result, the length of the copper wire used for the number of turns for obtaining the same magnetomotive force can be shortened, so that the resistance of each exciting coil 122, 127 can be reduced. Therefore, a large exciting current can be passed through the exciting coils 122 and 127, so that the same magnetomotive force can be obtained with a smaller number of turns. Further, since the impedance is reduced by reducing the number of turns, the exciting current rises faster, and a large driving force can be generated. As a result, the spool 18 can be driven at high speed, and the responsiveness can be improved. further,
Since the amount of copper wire used is reduced, the material cost is reduced and the weight of the electromagnetic proportional control valve 2 can be reduced.

Further, since the two exciting coils 122 and 127 do not house the movable iron core 23 therein but are arranged separately on both sides of the movable iron core 23, the electromagnetic proportional control valve 2 can be flattened. As a result, the degree of freedom when installing the electromagnetic proportional control valve 2 is improved. Further, it becomes easy to connect a manifold for supplying and exhausting air to and from each port 112, 113, 114 of the electromagnetic proportional control valve 2.

Further, since the movable iron core 23 is not housed inside the exciting coils 122 and 127, the magnetic core 12
The shapes of 1, 126 and the magnetic paths 123, 124 can be simplified. For this reason, the workability of the magnetic cores 121 and 126 and the magnetic paths 123 and 124 is improved, and restrictions due to the shape are reduced. Wood can be used. As a result, the electromagnetic proportional control valve 2 can be further downsized and the responsiveness can be improved.

The present invention is not limited to the above embodiment, but may be configured as follows. (1) In the first embodiment, the spool drive current ID1 may be a direct current.

Further, in the second embodiment, the spool drive current ID2 may be a direct current. (2) In the third embodiment, the bias exciting current IB may be a direct current.

(3) In the first embodiment, the first
Bias / dither current composed of a pulse signal is generated by the driving unit 40 of the spool 1 and the spool 1 is generated by the first exciting coil 32.
Bias 8 to a displaced position that does not reach the closed position and provide dither. In addition, the second drive unit cooperates with the bias / dither current to bias the spool 18 to the closed position and generate the bias / spool drive current for driving the spool 18 to the displacement position corresponding to the control deviation signal ΔV. The second exciting coil 33 may bias the spool 18 to the closed position and drive the spool 18 with the closed position as 0 point. Even with this configuration, the number of turns of each exciting coil 32, 33 can be reduced, so that the impedance can be reduced and the responsiveness can be improved.

(4) In the first to fourth embodiments, the positions of the first exciting coils 32, 61 and 122 and the second exciting coils 33, 62 and 127 may be exchanged. (5) In each of the embodiments, the first exciting coils 32, 61, 122 and the second exciting coils 33, 62, are provided in one of the displacement directions of the spool 18 or the poppets 99, 102.
Although 127 is provided, spool 18 or poppet 9
It is also possible to use an electromagnetic proportional control valve in which the first exciting coil is provided in one of the displacement directions of 9, 102 and the second exciting coil is provided in the other.

(6) In the fourth embodiment, the first exciting coil portion 120 and the second exciting coil portion 125 are arranged at an angular interval of 180 ° with respect to the central axis of the movable iron core 23. , 180 ° may be provided, for example, 90 °. By setting this angular interval according to the mode in which the electromagnetic proportional control valve 2 is used, it is possible to easily connect the manifold to each port and to easily install the electromagnetic proportional control valve 2.

(7) The electromagnetic proportional control valve in each of the embodiments is not limited to the 3-port valve and may be a 4-port valve. (8) The solenoid proportional control valve in each of the first, second and fourth embodiments is not limited to the spool valve and may be a slide valve.

(9) In each of the above embodiments, the electromagnetic proportional control valve 2 is configured as a flow rate control valve, and the electromagnetic proportional control valve 2 is used in a pressure control device for controlling the pressure of the air supplied to the load L. Carried out. It is also possible to configure the electromagnetic proportional control valve 2 as a pressure proportional control valve to control the pressure supplied to the load L. That is, the output port 14 of the electromagnetic proportional control valve 2 is communicated with the port 21, and the actual pressure P0 is applied to the spool 1.
The spool 18 is fed back so as to be applied to the left end of the spool 8, and the total thrust force, which is the sum of the biasing force of the compression coil spring 20 and the thrust force of the actual pressure P0, opposes the driving force of the first and second exciting coils. Is driven, and the spool 18 is arranged in the closed position in a state where the driving force and the total thrust are balanced. As a result, the electromagnetic proportional control valve 2 itself causes the movable iron core 23
The actual pressure P.sub.0 is controlled according to the driving force acting on the magnet, that is, the total exciting current supplied to both exciting coils 32 and 33.
That is, the first exciting coil 32 or the second exciting coil 33
When either one or both of them are supplied with the exciting current for setting the actual pressure P0, the pressure proportional control valve controls the actual pressure P0 according to the exciting current. As shown in FIG. 9, it is also possible to configure an air pressure control device 130 for controlling the piston position of an air cylinder or the like by using two pressure proportional control valves.

In the pneumatic control device 130, the first pressure proportional control valve 132 is connected to the head side piston chamber of the air cylinder 131, and the second pressure proportional control valve 133 is connected to the rod side piston chamber. The first pressure proportional control valve 132 is connected to the first solenoid valve driving device 134 having the same configuration as that of the first embodiment, and the second pressure proportional control valve 133 is connected.
The second solenoid valve driving device 135 having the same configuration is also connected to the above.

From the first driving portion of the first solenoid valve driving device 134, the bias pressure current for setting the pressure of the head side piston chamber to half the pressure of the supplied air is set to the first pressure. Output to the first exciting coil of the proportional control valve 132. Further, from the first drive portion of the second solenoid proportional control valve 135, the bias pressure current for setting the pressure of the rod side piston chamber to half the pressure of the supplied air is proportional to the second pressure proportional. Output to the first exciting coil of the control valve 133. As a result, the piston 136 is placed in place by the balancing pressure.

On the other hand, the piston position of the air cylinder 131 is detected by the piston position detector 137, and the detected value is output to the deviation amplifier 6 as the piston position signal VPK. or,
The control signal generator 8 outputs a target piston position signal VPP corresponding to the target piston position to the deviation amplifier 6.
The operational amplifier amplifies the deviation between the target piston position signal VPP and the piston position signal VPK, and outputs it as a control deviation signal ΔV to each second drive section of each solenoid valve drive device 134, 135. The first solenoid valve drive device 134 controls the control deviation signal Δ
The first pressure setting current IP1 corresponding to V is output to the second exciting coil of the first pressure proportional control valve 132. at the same time,
The second solenoid valve driving device 135 outputs the second pressure setting current IP2 corresponding to the control deviation signal ΔV to the second exciting coil of the second pressure proportional control valve 133. The first pressure setting current IP1 and the second pressure setting current IP2 have the same magnitude. However, the second electromagnetic valve driving device is so arranged that the second exciting coil of the second pressure proportional control valve 133 is excited to the opposite polarity to the second exciting coil of the first pressure proportional control valve 132. The second pressure proportional control valve 13 with respect to the output end of 135
The second exciting coil of No. 3 is connected.

When the positive first pressure setting current IP1 is supplied to the second exciting coil, the first pressure proportional control valve 132 increases the actual pressure P0 by the amount of the first pressure setting current IP1. . At this time, in the second pressure proportional control valve 133,
Since the negative second pressure setting current IP2 is supplied to the second exciting coil, the actual pressure P0 is reduced by the second pressure setting current IP2. As a result, the piston 136
Since a differential pressure acts on the piston 136, the piston 136 is driven to the rod side. Then, since the control deviation signal ΔV is controlled to be 0, the piston 136 is controlled to the target piston position.

At this time, each solenoid valve drive device 134, 13
By setting the frequency of the bias pressure current output by each first drive unit of 5 to the frequency for generating dither,
It is possible to give dither having a constant amplitude to each spool 18 of each pressure proportional control valve 132, 133 regardless of the displacement position. As a result, since the actual pressure P0 can be controlled with high accuracy by controlling each spool 18 with high accuracy, the piston position can be controlled with high accuracy.

When the pressure proportional control valves 132 and 133 are poppet valves, the frequencies of the first pressure setting current IP1 and the second pressure setting current IP2 are set to the dither generating frequency. , Dither can be applied to each poppet displaced from each closed position.

(10) Similarly to (9), the electromagnetic proportional control valve may be configured as a pressure proportional control valve to configure the thrust control device 140 of the air cylinder as shown in FIG. In this thrust control device 140, the air cylinder 13
The pressure proportional control valve 141 is connected to the first head side piston chamber, and the pressure reducing valve 142 is also connected to the rod side piston chamber. An electromagnetic valve drive device 143 having the configuration shown in FIG. 11 is connected to the pressure proportional control valve 141. Solenoid valve drive device 143
Is a first drive unit 144 that controls the bias pressure and a second drive unit 145 that controls the differential pressure with respect to the bias pressure.
It is composed of

The pressure in the rod side piston chamber of the air cylinder 131 is detected by the pressure detector 146, and the detected value is output to the first drive section 144 as the bias pressure setting signal VBP. Based on the bias pressure setting signal VBP, the first driving section 144 supplies the bias pressure current IBP to the first exciting coil 147 of the pressure proportional control valve 141. With this bias pressure current IBP, the pressure proportional control valve 141 controls the pressure in the head-side piston chamber to a bias pressure that balances the pressure in the rod-side piston chamber. As a result, the piston 13
6 is controlled to be stationary.

To drive the piston 136, the differential pressure setting signal VDP is sent from the control signal generator 8 to the second drive section 145.
Is output. The second drive unit 145 outputs the differential pressure generation current IDP to the second exciting coil 148 based on the differential pressure setting signal VDP. The pressure proportional control valve 141 increases or decreases the pressure in the head side piston chamber by the differential pressure generation current VDP. As a result, a differential pressure acts on the piston 136, so that the piston 136 is driven to the head side or the rod side.

When the piston 136 is displaced to the rod side,
The air in the rod side piston chamber is compressed and its pressure increases. Then, since the bias pressure setting signal VBP increases, the bias pressure of the head side piston chamber set by the pressure proportional control valve 141 also increases. On the contrary, the piston 136
Is displaced toward the head side and the pressure in the rod side piston chamber decreases, the bias setting signal VBP decreases and the bias pressure in the head side piston chamber set by the pressure proportional control valve 141 decreases. That is, by driving the piston,
Even if the pressure in the rod-side piston chamber changes, the bias pressure in the head-side piston chamber is controlled so as to be balanced with the pressure in the rod-side piston chamber based on the bias pressure setting signal VBP corresponding to the pressure. Therefore, even if the pressure in the head side piston chamber controlled by the pressure reducing valve 142 is unstable, the differential pressure set by the differential pressure setting signal VDP is always applied to the piston 136 with high accuracy. Therefore, the piston can be always driven with a constant thrust, and thus highly accurate thrust control can be performed. According to the thrust control device 140, the direction switching valve for switching the driving direction of the piston 136 can be eliminated.

Also in this thrust control device 140, the first
By setting the frequency of the bias pressure current IBP of the drive unit 144 of (1) to a frequency that generates dither, dither can be applied to the spool of the pressure proportional control valve 141. In this case, since the fluctuation range of the bias pressure current IBP is relatively small, the fluctuation range of the amplitude of the dither given to the spool by the bias pressure current IBP is small. Therefore, dither having a substantially constant amplitude can be applied to the spool regardless of the displacement position. As a result, the total pressure in the head-side piston chamber can be controlled with high precision by controlling the spool with high precision, so that the thrust of the piston can be controlled with high precision.

When the pressure proportional control valve 141 is a poppet valve, the frequency of the differential pressure generation current IDP generated by the second drive section 145 is set to a frequency for generating dither, so that each closed position is controlled. You can give dither to each poppet that is displaced from.

The technical ideas other than the claims that can be understood from the above-described embodiment will be described below along with their effects. (1) In the control method for an electromagnetic proportional control valve according to claim 1, the valve body drive currents ID1 and ID2 are pulse currents.
According to this configuration, the valve body drive currents ID1 and ID2 can be generated with the same circuit configuration as the circuit that generates the pulse excitation currents IB and IDT for exciting the first excitation coil. Therefore, by changing the frequencies of the valve body drive currents ID1 and ID2, it is possible to easily change the valve body drive currents ID1 and ID2 so that the valve body 18 is dithered.

(2) In the electromagnetic proportional control valve according to claim 4, the exciting coils 122 and 127 are connected to the movable iron core 23.
It is provided on the side opposite to each other across. According to this configuration, the first exciting coil 122 and the second exciting coil 12
Since 7 is arranged on both sides of the movable iron core 23, the electromagnetic proportional control valve can be flattened.

[0119]

As described in detail above, according to the invention described in claim 1 or 2, the dither applied to the valve body can be suitably controlled according to the displacement position of the valve body.

According to the first aspect of the invention, it is possible to apply dither with a constant amplitude to the valve body regardless of the displacement position of the valve body. According to the invention as set forth in claim 2, it is possible to prevent the valve body from being dithered when the valve body is in the closed position. Therefore, when the poppet is used as the valve element, it is possible to prevent the poppet from colliding with the valve seat at the closed position and prevent the poppet and the valve seat from being damaged. You can

According to the third aspect of the present invention, the valve body is independent of the exciting current for biasing the valve body and the drive current for driving the valve body to the target displacement position without complicating the structure. Can be controlled. Therefore, since dither having a constant amplitude can be provided regardless of the displacement position of the valve body, dither having a high dither effect can be obtained regardless of the displacement position of the valve body. Further, the valve body can be independently controlled by the exciting current that biases the valve body to the closed position and the drive current that drives the valve body from the closed position to the target displacement position. Therefore, since the dither can be stopped when the valve body is in the closed position, damage to the valve body in the closed position can be prevented.

According to the invention described in claim 4, since the exciting coil can be downsized, the impedance can be reduced and the responsiveness can be improved while maintaining the driving force for the valve body. Further, since the exciting coil can be arranged on the side of the movable iron core, the flattening can be achieved. Further, since the amount of copper wire used can be reduced, the material cost can be reduced and the weight can be reduced. Furthermore, since it is possible to use a magnetic material that is difficult to process but has excellent magnetic properties, it is possible to reduce the size and improve the responsiveness.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electromagnetic proportional control valve according to a first embodiment.

FIG. 2 is a block diagram of a pressure control device.

FIG. 3 is a block diagram of a solenoid valve driving device.

FIG. 4 is a sectional view of an electromagnetic proportional control valve according to a second embodiment.

FIG. 5 is a block diagram of a solenoid valve driving device.

FIG. 6 is a sectional view of an electromagnetic proportional control valve according to a third embodiment.

FIG. 7 is a side sectional view of an electromagnetic proportional control valve according to a fourth embodiment.

FIG. 8 is a front side sectional view of the same.

FIG. 9 is a block diagram of a piston position device using a pressure proportional control valve of another example.

FIG. 10 is a block diagram of a thrust control device.

FIG. 11 is a block diagram of a solenoid valve driving device.

FIG. 12 is a sectional view of a conventional electromagnetic proportional control valve.

[Explanation of symbols]

18 ... Spool as valve body, 23 ... Movable iron core, 32 ...
1st exciting coil, 33 ... 2nd exciting coil, 61 ... 1st exciting coil, 62 ... 2nd exciting coil, 99, 10
2 ... Poppet as valve body, 117 ... Spool as valve body, 122 ... First exciting coil, 127 ... Second exciting coil, IB ... Bias exciting current as pulse exciting current, ID1, ID2 ... Valve body driving Spool drive current as current, ID3 ... Poppet drive current as pulse drive current,
IDT: Dither current as pulse exciting current.

Claims (4)

[Claims] 1. A movable iron core (2) for displacing a valve body (18).
In the control method of the electromagnetic proportional control valve, which supplies the exciting current corresponding to the target displacement position to the exciting coil for driving 3) to displace the valve body (18) to the target displacement position, the frequency and pulse width are set in advance. The first exciting coil (3 which is excited by the set pulse exciting current (IB, IDT)
2, 61) dithers the valve body (18), is provided independently of the first exciting coil (32, 61), and has a size controlled based on the target displacement position. A method for controlling an electromagnetic proportional control valve, wherein a valve body (18) is displaced to a target displacement position by a second excitation coil (33, 62) excited by (ID1, ID2). 2. An exciting current corresponding to a target displacement position is supplied to an exciting coil that drives a movable iron core (23) for displacing the valve body (99, 102) to bring the valve body (99, 102) to a closed position. In the control method of the electromagnetic proportional control valve that is biased and driven bidirectionally from the closed position to the target displacement position, the first magnetic field is excited by the bias exciting current (IB) whose magnitude is set in advance. The excitation coil (32) of No. 1 causes the valve body (9
9, 102) is biased to the closed position and is provided independently of the first exciting coil (32),
The valve body (99, 102) is displaced from the closed position to the target displacement position by the second exciting coil (33) that is excited by the pulse drive current (ID3) that is pulse-modulated according to the target displacement position, and A control method for an electromagnetic proportional control valve, which is designed to give dither to the body (99, 102). 3. An exciting current (IB) corresponding to the target displacement position.
, IDT, ID1, ID2, ID3), the valve body (1
Movable iron core (2, 99, 102, 117)
3) In an electromagnetic proportional control valve having an exciting coil for driving the exciting coil, the exciting coil is replaced by a first exciting coil (32, 61, 12).
2) and the second exciting coil (33, 62, 127), and each exciting coil is formed by a valve body (18, 99, 10).
2, 117) An electromagnetic proportional control valve provided on one side in the displacement direction. 4. A first exciting coil (32, 61, 12)
2) and the second exciting coil (33, 62, 127),
The solenoid proportional control valve according to claim 3, wherein the electromagnetic proportional control valves are arranged side by side on a movable iron core (23) driven by each exciting coil.