JPH07110078A - Proportional electromagnetic control valve - Google Patents

Abstract

PURPOSE:To obtain high-speed responsiveness by taking a movable part of an electromagnetic solenoid plunger device as a movable element not showing any damping property in relation to the oil-in movement and limiting increase of exciting current so as to restrain the vibration in stopping of the movable element following the rising of exciting current. CONSTITUTION:An electromagnetic solenoid plunger device 1 is composed of a movable element wherein a movable iron core 15 and rods 16a, 16b do not show any damping property in relation to the oil-in movement, and having a light mass. A current driver device 4 supplies exciting current to a solenoid coil 11, the exciting current is detected by a current detecting resistance 44, and a comparison input is input to a feedback element 46 from a comparing circuit 45 when the detected current exceeds the reference, and a negative feedback signal of amplitude according to it is given to an adding circuit 42, and the exciting current of an amplifier 43 is restrained to the specific upper limit. Accordingly, vibration at the time that the movable element is stopped following rising of the exciting current is restained and matched to the optimum vibration damping property by only the adjustment of an electric system, and high-speed responsiveness of the target equipment can be exhibited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proportional electromagnetic control valve device for controlling the pressure or flow rate of hydraulic fluid to a desired value in response to a command signal.

[0002]

2. Description of the Related Art A conventional proportional electromagnetic control valve device is an oil immersion type electromagnetic solenoid plunger device having a parallel attractive force characteristic that produces a mechanical output proportional to an exciting current, and is displaced by a spring force by the mechanical output. A fluid control valve device for controlling the pressure or flow rate of the fluid, and a current driver device for supplying an output current corresponding to a pre-given input signal to the electromagnetic solenoid plunger device as the exciting current, particularly to a load. The closed loop control that detects the fluid output information of the supplied control valve and feeds it back to the electric system is a stable electro-hydraulic control such as the control of the discharge amount and the discharge pressure of the variable displacement hydraulic pump. It is widely used as a valve device instead of the servo valve.

When viewed as a control system, a proportional electromagnetic control valve device includes a mechanical system including a fluid control valve device from a movable iron core of the electromagnetic solenoid plunger device, and an electric system including a current driver device and a coil of the electromagnetic solenoid plunger device. It is a complex system. In the conventional proportional solenoid control valve device,
The mechanical system is designed to maintain the stability of transient characteristics by itself, and the electrical system is configured to include a current limiting circuit so that excessive current does not flow to the load in the transient state.

That is, as for the mechanical system, in a general conventional proportional solenoid control valve device, an axially penetrating oil passage is provided in a movable iron core of an oil immersion type electromagnetic solenoid plunger device, and this oil passage is appropriately fixed. By arranging the diaphragm, smooth movement without vibration is given at the time of starting and stopping the movement of the movable iron core, and the plunger rod (pin) that moves with the movable iron core is supported by sliding bearings to suppress vibrations in the mechanical system itself. For the electric system, a current limiter circuit is inserted before the output stage of the current driver device so that an excessive output current does not occur when the input signal rises.

This type of proportional electromagnetic control valve device is used in combination with the controlled object equipment such as the variable displacement hydraulic pump described above. Therefore, in the conventional proportional electromagnetic control valve device, a mechanical system is used. The damping characteristics of are designed and adjusted individually in advance so as to meet the ratings and characteristics of the control target equipment and operating conditions.

[0006]

As described above, according to the conventional concept of the proportional solenoid control valve device, the mechanical system has stable damping characteristics by itself, and the electrical system has such a mechanical system. It should be designed to give the optimum drive current.

In the conventional proportional solenoid control valve device designed based on such a concept, when used in combination with a control target device such as a variable displacement hydraulic pump, the control function for the control target device has a specific use condition of the target device. Although it is optimal under the following conditions, for example, when the conditions of the load operated by the target device are changed, such as when changing the molding conditions in an injection molding machine using the pump as a drive source, each time, It is inevitable that the mechanical system of the proportional solenoid control valve device will be modified or replaced and the electrical system will be readjusted to suit the operation of the controlled device under the changed conditions. It is necessary to always have a coordinating and maintenance person who goes to the site to deal with the request from the user side.

The present invention has been made in view of the above problems, and an object thereof is to adjust an electric system only when it is used in combination with a control target device used under various conditions. To provide a proportional electromagnetic control valve device capable of coping with the above, and in any case realizing a high responsiveness of a fluid control output with respect to a step input signal and sufficiently exhibiting a high-speed responsiveness of a controlled device. is there.

[0009]

A proportional electromagnetic control valve device according to the invention of claim 1 is an oil immersion type electromagnetic solenoid plunger device for producing a mechanical output proportional to an exciting current in a movable part, and a spring by the mechanical output. A fluid control valve device that controls the pressure or flow rate of the fluid by displacing through force, and a current driver device that supplies an output current according to a pre-given input signal to the electromagnetic solenoid plunger device as the exciting current. In order to achieve the above-mentioned problems, in particular, the movable part of the electromagnetic solenoid plunger device is composed of a movable element that does not exhibit substantially damping characteristics against movement in oil, and the current driver device includes: The increase of the exciting current is suppressed so as to suppress the vibration of the movable element when the movement of the movable element is stopped due to the rising of the exciting current. It is characterized in that provided in the feedback system of the current control circuit for limiting.

Further, in the proportional electromagnetic control valve device according to a second aspect of the invention, in the proportional electromagnetic control valve device according to the first aspect, the current limiting circuit detects the magnitude of an exciting current flowing through the electromagnetic solenoid plunger device. When the magnitude of the detection output exceeds the reference voltage by comparing the detection output with a detection unit that produces an output and a predetermined reference voltage, a feedback signal for limiting an increase in the exciting current is applied to the current. A current limiting feedback circuit provided to the input side of the driver device is provided.

Further, in the proportional electromagnetic control valve device according to the invention of claim 3, in the proportional electromagnetic control valve device according to claim 2, the current limiting feedback circuit is provided with a delay circuit element for phase lead compensation.

According to a fourth aspect of the present invention, in the proportional solenoid control valve device according to the first aspect, the movable element of the electromagnetic solenoid plunger device is supported and guided by the rolling bearing means.

According to a fifth aspect of the present invention, in the proportional electromagnetic control valve device according to the first aspect, the movable element of the electromagnetic solenoid plunger device reduces movement resistance and reduces weight. It has a cavity.

[0014]

According to the invention of claim 1, the movable part of the oil-immersed electromagnetic solenoid plunger device is composed of a movable element which does not exhibit substantially damping characteristics against movement in oil. , A movable iron core that moves axially by a fixed iron core and a magnetic attraction force of a yoke in a closed pipe fitted in the hole of a cylindrical coil of an oil immersion type electromagnetic solenoid plunger device, and a plunger rod that moves following it in oil It means a light moving mass as the mechanical moving load. That is, in such a moving load configuration, a damping constant for vibration in a transient state is preferably smaller than 1 when viewed as a mechanical system, and it takes a long time for itself to damp the vibration in the transient state. Is.

On the other hand, the current driver device for driving such a mechanical system by electromagnetic force suppresses the vibration of the movable element when the movement of the movable element is stopped due to the rise of the exciting current. The feedback system is provided with a current control circuit that limits an increase in current. That is, when the step input signal given to the current driver device rises, the movable element, which is a light moving load as described above, immediately starts moving and starts moving at a high response speed that almost follows the rising speed of the exciting current. When the input current reaches a predetermined set level, the exciting current is sharply suppressed by the current limiting circuit so as not to increase above the corresponding level.

This current limiting circuit is provided in the feedback system of the current driver device, and the exciting current itself flowing in the solenoid coil is the feedback information.
Therefore, unlike the conventional case where the current limiter circuit is provided in the preceding stage of the output circuit of the current driver device, the feedback control which monitors the change of the exciting current itself which is the control target of the current limiting operation and limits its increase. Even if a general operational amplifier is used in the output circuit, by appropriately selecting the loop gain of the feedback circuit, it is possible to adjust a wide range by the electric system for a moving load with a small damping constant of the mechanical system. It is possible to provide a desired damping characteristic.

As described above, according to the present invention, the movable element, which has a load as light as possible, is driven and controlled at a high response speed with a desired damping characteristic by the current control of the current driver device. Since the characteristics can be adjusted by adjusting the gain of the feedback circuit, it can be used under various conditions without modification or replacement of the mechanical system by simple adjustment work. If it is configured by a digital circuit, this adjustment work itself can be completed by simply rewriting the program data.

The movable element of the electromagnetic solenoid plunger device naturally bears the elastic load including the valve body and the valve spring of the fluid control valve device and the dynamic load including the flow force of the control fluid. In this case, the force of the valve spring of the fluid control valve device is increased by, for example, 50% more than that of the conventional general proportional electromagnetic control valve, and the coil of the electromagnetic solenoid plunger device is correspondingly increased by, for example, 6 of the conventional equivalent product.
By lowering the current to about 0% and increasing the current, the response of the entire device rises to 50 msec or less.
It can be as fast as the fall time.

According to another aspect of the present invention, the current limiting circuit has a detecting means for producing a detection output corresponding to the magnitude of the exciting current flowing through the electromagnetic solenoid plunger device, and the detection output has a predetermined reference voltage. And a current limiting feedback circuit for giving a feedback signal for limiting the increase of the exciting current to the input side of the current driver device when the magnitude of the detection output exceeds the reference voltage. .

The detecting means can be composed of, for example, a current detecting resistor inserted in series with the coil of the electromagnetic solenoid plunger device. The magnitude of the exciting current flowing through the coil is detected as a voltage drop across the current detecting resistor. The detected voltage is compared with a reference voltage by, for example, a voltage comparator in a current limiting feedback circuit, and when the detected voltage exceeds the reference voltage, the current feedback circuit limits the increase of the exciting current to the input side of the current driver device. A feedback signal is provided to do so. Therefore, this feedback circuit is preferably designed to have a relatively high gain of greater than one, thereby providing a sufficient negative feedback signal to the current driver device when the voltage comparator produces an output.

In the invention of claim 3, the current limiting feedback circuit includes a delay circuit element for phase lead compensation. This delay circuit element, since the load of the current driver device is inductive, gives an optimal phase delay to the feedback signal based on the detection output of the detection means, so that the current limiting operation is performed with high responsiveness, A time constant according to the load inductance is given in advance.

In the invention of claim 4, the movable element of the electromagnetic solenoid plunger device is supported and guided by the rolling bearing means. That is, specifically, by supporting a plunger rod (pin), which moves together with the movable iron core of the oil-immersed electromagnetic solenoid plunger device, with a rolling bearing such as a linear ball bearing, sliding friction against the axial movement of the movable element is reduced. It can be virtually eliminated.

In the fifth aspect of the invention, the movable element of the electromagnetic solenoid plunger device has a hollow portion for reducing the movement resistance and reducing the weight. This cavity can be achieved by providing the movable iron core of the oil-immersed electromagnetic solenoid plunger device with a relatively large diameter axial through oil passage that does not cause a substantial fluid throttling effect. It is also possible to reduce the weight by forming a thinned portion in a portion other than the thickened portion near the outer circumference. In this case, the thick portion near the outer periphery of the movable iron core is left because most of the magnetic flux that contributes to the movement of the movable iron core passes through the thick portion near the outer periphery, and the other portions are almost free from the magnetic attraction force. This is because it does not contribute.

As described above, according to the proportional electromagnetic control valve device of the present invention, when used in combination with the equipment to be controlled which is used under various conditions, the optimum vibration damping characteristic is obtained only by adjusting the electric system. In any case, a high response of the fluid control output to the step input signal can be realized and the high-speed response of the control target device can be sufficiently exhibited.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the structure of a proportional electromagnetic control valve device according to one embodiment of the present invention in a cross section with respect to the main part, and FIG. The example of a structure is shown. In FIG. 1, the proportional electromagnetic control valve device of the present embodiment is displaced by an oil immersion type electromagnetic solenoid plunger device 1 that produces a mechanical output proportional to an exciting current in a movable part and a spring force by the mechanical output. And a fluid control valve device 2 for controlling the pressure or flow rate of the fluid, and an electric equipment box 3 having a built-in current driver device for supplying the electromagnetic solenoid plunger device 1 with an output current corresponding to an input signal given in advance as the exciting current. It consists of and.

The electromagnetic solenoid plunger device 1 is
The cylindrical solenoid coil 11 is provided with a fixed iron core 12 and a tubular yoke 13 which form a series of closed tubes in the inner hole, and the tail end of the tubular yoke 13 is sealed by an end plug 14. The inside of the sealed tube is filled with hydraulic oil from the control valve device 2 side, and a movable iron core 15 as a movable part is movably arranged in the oil-immersed sealed tube. The movable iron core 15 has an axial through hole 18 having a relatively large diameter, and plunger rods 16a and 16b are coaxially integrated with both end faces of the movable iron core 15, respectively. The rods 16a and 16b at both ends are supported and guided by linear ball bearings 17a and 17b fixed to the axial center hole of the fixed iron core 12 and the inner surface of the tubular yoke 13, respectively. With such a configuration, the movable iron core 15 and the rods 16a,
16b constitutes a relatively light-mass moving element which exhibits substantially no damping properties against movement in oil.

The fluid control valve device 2 incorporates a valve seat 21 and a poppet valve body 22 which constitute a fluid control section, and the poppet valve body 22 is driven to be displaced by the plunger rod 16b via a valve spring 23 arranged in series. It The basic structure of the fluid control valve itself is almost the same as that of the well-known proportional electromagnetic control valve, but in order to obtain high response, the flow rate gain of the fluid control unit should be relatively large. desirable.

An example of the circuit configuration of the current driver device in the electrical equipment box 3 is shown in FIG. The current driver device 4 is a power amplifier that supplies an exciting current to the solenoid coil 11 in response to a command input signal IN from a control amplifier device (not shown), and includes an input circuit 41, an adding circuit 42, a current amplifier 43, and It includes a current detection resistor 44, a comparison circuit 45, and a feedback element 46.

The input circuit 41 can be a preamplifier having a predetermined proportional constant K if the command input signal IN is an analog signal, and has a predetermined digital / analog conversion function if the command input signal IN is a digital signal. It can be a circuit. The signal output from the input circuit 41 excites the current amplifier 43 via the adder circuit 42, whereby an exciting current proportional to the input is supplied to the solenoid coil 11 from the current amplifier 43.

This exciting current is detected as a voltage drop by the current detection resistor 44, and this detected voltage is detected by the comparison circuit 45.
Has been entered in. A reference voltage REF is also input to the comparison circuit 45 from a control amplifier (not shown), and when the detection voltage of the current detection resistor 44 exceeds this reference voltage, a comparison output is given to the feedback element 46.

The feedback element 46 is an active circuit having a relatively high gain of higher than 1, and further includes a time constant element for giving a preset delay to the input / output transfer characteristic. Therefore, when the comparison output from the comparison circuit 45 is input to the feedback element 46, the feedback element provides the addition circuit 42 with a negative feedback signal having an amplitude corresponding to the comparison output at a steep rise after the set delay time. . As a result, the input signal given from the adder circuit 42 to the current amplifier 43 is immediately suppressed to a value corresponding to the reference voltage, and the exciting current output from the amplifier 43 is immediately suppressed to a predetermined upper limit value.

Due to the operation of the feedback loop, the increase of the exciting current of the solenoid coil 11, which is an inductive load, is advanced and the response is limited together with the phase compensation, whereby the movement of the movable element accompanying the rising of the exciting current is caused. The vibration of the movable element at the time of stop is suppressed. In this case, the upper limit level of the exciting current by the current driver device 4 can be arbitrarily set by changing the value of the reference voltage, and the time constant of the delay element given to the feedback element can be easily adjusted by, for example, a variable resistor. Therefore, the damping characteristics of the entire device can be adjusted as desired.

[0033]

As described above, according to the proportional solenoid control valve device of the present invention, when it is used in combination with a controlled device used under various conditions, it is optimal only by adjusting the electric system. Can be adjusted to various vibration damping characteristics,
In any case, it is possible to realize a high responsiveness of the fluid control output with respect to the step input signal and to sufficiently exhibit the high-speed responsiveness of the controlled device.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a structure of a proportional electromagnetic control valve device according to an embodiment of the present invention in cross section with respect to a main part.

FIG. 2 is a circuit diagram showing a configuration example of an electric system of a proportional electromagnetic control valve device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Oil-immersion type electromagnetic solenoid plunger device 2 Fluid control valve device 3 Electrical equipment box 4 Current driver device 11 Solenoid coil 12 Fixed iron core 13 Cylindrical yoke 14 End plug 15 Movable iron core 16a, 16b Plunger rod 17a, 17b Linear ball bearing 18 Shaft Directional through hole 21 Valve seat 22 Poppet valve body 23 Valve spring 41 Input circuit 42 Adder circuit 43 Current amplifier 44 Current detection resistor 45 Comparison circuit 46 Feedback element

Claims (5)

[Claims] 1. An oil-immersed electromagnetic solenoid plunger device that produces a mechanical output in a movable part in proportion to an exciting current, and a fluid that controls the pressure or flow rate of the fluid by being displaced by a spring force by the mechanical output. A control valve device,
In a proportional electromagnetic control valve device including a current driver device that supplies an output current according to a pre-given input signal to the electromagnetic solenoid plunger device as the exciting current, a movable part of the electromagnetic solenoid plunger device moves in oil. To the excitation element, the current driver device suppresses the vibration of the movable element when the movement of the movable element is stopped due to the rise of the excitation current. A proportional electromagnetic control valve device comprising a current control circuit for limiting an increase in current in a feedback system. 2. The detection means, wherein the current limiting circuit produces a detection output corresponding to the magnitude of the exciting current flowing in the electromagnetic solenoid plunger device, and the detection output by comparing the detection output with a predetermined reference voltage. A current limiting feedback circuit for providing a feedback signal for limiting an increase in the exciting current to an input side of the current driver device when the magnitude of the output exceeds the reference voltage. 1. The proportional electromagnetic control valve device according to 1. 3. The proportional electromagnetic control valve device according to claim 2, wherein the current limiting feedback circuit includes a delay circuit element for phase lead compensation. 4. The proportional electromagnetic control valve device according to claim 1, wherein the movable element of the electromagnetic solenoid plunger device is supported and guided by rolling bearing means. 5. The proportional electromagnetic control valve device according to claim 1, wherein the movable element of the electromagnetic solenoid plunger device has a cavity for reducing movement resistance and reducing weight.