JPH09280410A - Excitation current controller for solenoid - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an exciting current control device for a solenoid device of a solenoid valve, which is not easily affected by variations in component parts of the solenoid valve and fluctuations in switching signal voltage, and which can be realized without adjusting points. To do. An output of a first time constant circuit that changes an input signal with a first time constant, and a first time constant circuit.
The output of the first adder 108 that adds the output of the second time constant circuit 103 that changes the output of 2 with the second time constant;
The added value with the second reference voltage 105 output according to the output of the first time constant circuit 102 and the solenoid 101
Drive current feedback voltage of the second comparator 113
The power switching element 114
On / off control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exciting current control device for a solenoid used in a solenoid device of a solenoid valve for switching between opening and closing of a fluid passage, which is capable of reducing the machine difference of each solenoid valve characteristic at the time of switching.

[0002]

2. Description of the Related Art In a solenoid valve for switching between opening and closing of a fluid passage by a solenoid device, if the valve body is moved rapidly, a pressure shock may be generated in the fluid, which may cause unexpected troubles in the equipment. . An exciting current control device for a solenoid device for preventing such a shock is proposed in, for example, Japanese Patent Laid-Open No. 64-58890.

This is composed of a circuit as shown in FIG. 10. When a stepped input signal (switching signal) voltage is applied between the input terminals 201a and 201b, the voltage at the point C of this circuit becomes 11, the voltage rises stepwise to the divided voltage determined by the resistor 202 and the variable resistor 203 as shown by X to P in FIG. 11, and then gradually increases by charging the capacitor 204 as shown at P to Q in FIG. go.

This C point voltage becomes one input of the comparator circuit 205, and this C point voltage is the other input of the comparator circuit 205 and the E point voltage (voltage E _{1 in} FIG. 11).
Is exceeded, the comparator circuit 205 is turned off, the output point F voltage charges the capacitor 206, and the point H voltage is raised to a predetermined value H ₁ as indicated by X to Y in FIG.

On the other hand, at the same time when the input signal voltage between the input terminals 201a and 201b is turned off, the voltage at the point C changes to the resistor 202 and the variable resistor 203 as shown by R to S in FIG.
11 is reduced stepwise by the divided voltage, and then the capacitors 204 are discharged, so that S to T to V to W in FIG.
It gradually decreases as shown in.

At this time, when the voltage at the point C becomes lower than the voltage at the point H, the voltage at the point D is held at the same level as the voltage at the point H as shown in T to U of FIG. Further, the voltage at the point C is the voltage E
_When it becomes lower than ₁ , the comparator circuit 205 is turned on, and the voltage at the H point changes from U to U in FIG.
As shown in W, it gradually decreases.

As a result of the above, the change in the voltage at point D due to the on / off of the input signal voltage is as shown in the lower diagram of FIG. This D point voltage is successively compared with the reference signal (triangular wave signal) applied to the B point in the comparator circuit 207, and the exciting current of the solenoid 208 flowing through the K point is controlled by the output signal of this comparator circuit 207. The movement of the spool valve element of the solenoid valve is controlled by the balance between the suction force and the spring force of the solenoid 208.

[0008]

As described above, according to the conventional device shown in FIG. 10, by gradually increasing and gradually decreasing the voltage at the point D for controlling the solenoid exciting current with respect to the stepwise operation input, Although the exciting current of the solenoid device can be gradually increased and decreased at a predetermined set speed, the voltage at the point D is still increased during the period shown in X to P in FIG.

Therefore, during this period, the solenoid exciting current also increases stepwise, and the attraction force of the solenoid 208 also rapidly increases. Therefore, when the spring force of the solenoid valve is small, the acceleration of the valve spool becomes large,
As a result of the valve spool moving past the dead zone of the valve,
As shown in 2 (d), the flow rate of the fluid passing through the valve at the beginning of the flow (initial flow rate) becomes large, causing a large shock at the initial stage of switching. On the contrary, when the spring force is large, as shown in FIG. 12 (c), the dead time until the solenoid exciting current increases to the current value that generates the suction force necessary to go over the dead zone of the valve. It gets bigger.

By the way, when a plurality of such solenoid valves are manufactured, the spring force varies, so that the initial flow rate becomes too large and the dead time becomes large due to the machine difference of each solenoid valve. As a result, the characteristics of each solenoid valve vary.

Similar variations are also caused by variations in the input signal (switching signal). That is, since the voltage at point P in FIG. 11 is a divided voltage of the switching signal voltage, when the switching signal voltage increases, the voltage at point P also increases, and the attraction force of the solenoid 208 increases, resulting in FIG. As shown in, the initial flow rate becomes large and a large shock occurs at the initial stage of switching. On the other hand, when the switching signal voltage becomes small, the P point voltage also becomes small, and the solenoid 2
As a result of the decrease in the suction force of 08, as shown in FIG. 13 (b), the dead time until the current increases to the current value that generates the suction force required to go over the dead zone of the valve increases.

On the other hand, in this conventional device, the voltage at the point P is adjusted by the variable resistor 203 according to the machine difference of each solenoid valve, so that the adjustment man-hour is increased and extra cost is required. Since the adjustment is complicated and the handling is inconvenient, the productivity is poor, and the electrical box for mounting the solenoid valve becomes large in size.

The present invention focuses on such problems, and is less susceptible to variations in the components of the solenoid valve and fluctuations in the switching signal voltage. An object is to provide an exciting current control device.

[0014]

As shown in FIG. 1, a first invention is an exciting current control device for a solenoid 101 for controlling an exciting current flowing through a solenoid 101, and an input signal is changed with a first time constant. First time constant circuit 10
2, a second time constant circuit 103 that changes the output of the first time constant circuit 102 with a second time constant, and the output of the first time constant circuit 102 with a first reference voltage 104. To output the second reference voltage 105.
6, the output of the first time constant circuit 102 after passing through the first backflow prevention diode 107, and the second time constant circuit 1
A first adder 108 for adding the output of No. 03 and a detection resistor 1 for converting the drive current of the solenoid 101 into a voltage.
09, a second adder 111 for adding the output from the detection resistor 109 and the third reference voltage 110, and the first adder 111.
To the output of the adder 108 of the second backflow prevention diode 11
Second comparator 1 for comparing an added value obtained by adding the second reference voltage after passing through two and the output of the second adder 111.
13 and a power switching element 114 which is on / off controlled by the output of the second comparator 113.

The second invention comprises a flywheel diode 115 which absorbs a transient voltage generated from the solenoid 101 when the power switching element 114 is turned off.

In the third invention, the first time constant circuit 1 is provided.
02, the time constant can be set to any value.

A fourth invention is the second time constant circuit 10 described above.
3 has a variable resistor whose time constant can be adjusted to an arbitrary value.

A fifth aspect of the invention includes a variable resistor for adjusting the second reference voltage to an arbitrary value.

[0019]

[Action] In the first invention, the step-like switching signal voltage (A point voltage V _A of the circuit) is applied to the input terminal, the first
The point B voltage V _B divided by the time constant circuit 102 rapidly rises at the first time constant, and the point B voltage V _B is applied to one end of the first adder 108 through the first backflow prevention diode 107. While being input, the second time constant circuit 1
Through 03, the voltage at E point V _E gradually becomes the second time constant and is input to the other end of the first adder 108.

The voltage V _B at the point _B is determined by the first comparator 106.
Is input to one end of the first reference voltage 104 (C point voltage V
_C ), this first comparator 106 has V _B >
When it is V _C (that is, when the switching signal voltage V _A is on), it is turned on, the second reference voltage 105 is set to 0, and the G point voltage V _{G at} which the second reference voltage 105 passes through the backflow prevention diode is set. On the other hand, when V _B <V _C (that is, when the switching signal voltage V _A is off), it is turned off, and a predetermined voltage is generated as the second reference voltage 105 to generate a G point voltage V _G. Let Therefore, the H-point voltage V _H input to one end of the second comparator 113 is V _H = V _D + V _E when the switching signal voltage V _A is on, while the switching signal voltage V _A is off. In the case of, V _H = V _G + V _E.

At the other end of the second comparator 113, the drive current obtained by converting the drive current of the solenoid 101 by the detection resistor 109 and the third reference voltage 110 is added by the second adder 111. Current feedback voltage V
_I is input. The second comparator 113 receives the V _H and V _I
ON / OFF control of the power switching element 114 is performed so as to match with, and the drive current of the solenoid 101 is controlled.

As a result of the above, the stepwise switching signal voltage V
_{When A} is input, the solenoid drive current does not change stepwise, increases over time t ₁ (first time constant), and then slowly over time t ₂ (second time constant). Since the number of solenoids 101 increases, the solenoid 101 at the time t _{1 has} elapsed
By properly adjusting the suction force of the valve, the delay of valve operation at the time of switching due to the tolerance of the components of the individual valves is suppressed within a time t ₁ at the maximum, and the components of the individual valves are also similarly suppressed. The rapid increase in the flow rate at the time of switching due to the tolerance of the switching can be suppressed, the shock at the time of switching can be appropriately prevented, and the fluctuation amount of the solenoid attraction force can be suppressed to be small even with the fluctuation of the switching signal voltage. Therefore, it is possible to appropriately suppress the valve operation delay and the rapid increase in the initial flow rate due to the change in the switching signal voltage. Also, because this does not require special adjustment parts such as variable resistors, cost can be reduced by reducing the adjustment man-hours, handling is easy and productivity is improved, and the electrical box for mounting the solenoid valve is also available. Does not become large.

In the second aspect of the invention, the flywheel diode 115 absorbs the transient voltage excited by the solenoid 101 when the power switching element 114 is turned off. Therefore, the flywheel diode 115 transmits the transient voltage to another device connected to the apparatus. There will be no adverse effects.

In the third invention, since the time constant of the first time constant circuit can be set to an arbitrary value, an appropriate value can be set as the first time constant.

In the fourth invention, the time constant of the second time constant circuit can be adjusted to an arbitrary value, so that an appropriate value can be set as the second time constant.

In the fifth aspect of the invention, the second reference voltage can be adjusted to an arbitrary value, so that an appropriate value can be set as the second reference voltage.

[0027]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 2, the DC power source 28 has a solenoid 26 for driving a valve spool of a solenoid valve (not shown).
, And the power switching element 25 are connected in series, and the flywheel diode 27 is connected in parallel to the solenoid 26 in the opposite polarity. Further, the detection resistor 2 for converting the solenoid drive current flowing through the solenoid 26 into a voltage
2 is connected to the solenoid 26 in series.

The switching element 25 is a comparator 19 (see FIG.
Corresponding to the output of the second comparator 113), and one of the input terminals of the comparator 19 has a voltage across the detection resistor 22, a resistor 20 and a resistor 21. Bias voltage (Fig. 1
The drive current feedback voltage V _I is added (corresponding to the third reference voltage 110) (corresponding to the second adder 111 in FIG. 1). Here, this bias voltage is applied as a noise margin,
This is to prevent unnecessary switching due to noise.

Further, to the other input of the comparator 19, the point V voltage V _D after the point _B voltage V _B, which is the output of the first time constant circuit described later, has passed through the backflow prevention diode 9, and E point voltage V _E after the output of the time constant circuit has passed a buffer 15 2, resistor 16, is summed via a resistor 17 and resistor 18 (corresponding to adder 108 in FIG. 1) is input It is like this.

The comparator 8 (corresponding to the first comparator 106 in FIG. 1) is the output signal level of the first time constant circuit (point B voltage V
_B ) is a comparison voltage (C
By comparing with the point voltage V _C ), if V _B > V _C , it is turned on and the voltage output as the second reference voltage becomes 0.
(Therefore, F point voltage V _F = G point voltage V _G = 0), and if V _B <V _C , it turns off, and a predetermined F point voltage V _F is output as the second reference voltage. F point voltage V _F
The point G voltage V _G adjusted by the variable resistor 12 is input to the comparator 19 instead of the point D voltage after passing through the backflow prevention diode 13.

As shown in FIG. 3 as well, the first time constant circuit is a CR time constant circuit composed of resistors 1, 3, 4, 5 and a capacitor 2, and is a relatively small first time constant circuit.
The charging operation and the discharging operation are performed in accordance with the time constant t ₁ of the input terminal 9
It is controlled by the switching signal voltage input to a and 9b.

As shown in FIG. 4 as well, the second time constant circuit is a CR time constant circuit composed of a variable resistor 10 and a capacitor 14, and the output V _B from the first time constant circuit is The second time constant t ₂ which is input and is relatively large
The charging operation and the discharging operation are performed according to the above. The output of the second time constant circuit passes through the buffer 15 and is input to the comparator 19 as the E point voltage V _E. The second time constant t ₂ can be adjusted by the variable resistor 10.

Next, the operation of the circuit shown in FIG. 2 will be described with reference to FIG. This FIG. 5 shows the circuit A, B, E,
It shows the time change of the voltage at each point of G, H, and I.

When a step-shaped switching signal voltage V _A (magnitude V _AH ) is applied to the input terminals 9a and 9b, the capacitor 2 has a first time constant t determined by the resistor 1 and the capacitor 2.
It is quickly charged at ₁ , and the point B voltage V _B is
As shown in b, the _divided voltage V _BH by the resistors 1 and 5 is reached.

This point B voltage V _B causes the capacitor 14
Is the second time constant t due to the variable resistor 10 and the capacitor 14.
It is slowly charged at ₂ , and the E point voltage V _E reaches V _{EH as} shown in e to f of FIG. 5E.

Further, the voltage V B at the point _B is equal to the resistance 6 and the resistance 7.
The comparison voltage V _C determined by the above is compared in the comparator 8. In this case, since V _B > V _C , the comparator 8 is turned on and the F point voltage V _F becomes 0.

Therefore, the voltage V _{G at the} point G after the voltage V F at the point _F passes through the variable resistor 12 and the diode 13 for preventing backflow.
Also becomes 0 as shown in i to j of FIG.
The H point voltage V _{H which} is one of the input voltages is the voltage V _D and the voltage V _E after the B point voltage V _B has passed through the backflow prevention diode 9.
Is added through the resistors 16, 17, and 18, and after rapidly rising at the first time constant t ₁ (m in FIG. 5H, m to n to o in FIG. 5H).
~ N), and gradually rises at the second time constant t ₂ (Fig. 5H).
No).

At this time, in consideration of the tolerances of the components of the valve and the combination thereof, the solenoid equivalent to the maximum value of the spring force at the valve opening start position is obtained at the time point t ₁ when the switching signal voltage V _{A is} turned on. FIG. 5H of the H point voltage V _H , which is the current command value, so that the current for obtaining the attraction force flows.
At the point n (the voltage at the point H when the first time constant t ₁ elapses after the switching signal voltage is turned on).

On the other hand, the solenoid drive current flowing from the power source 28 to the solenoid 26 through the power switching element 25 is converted into a voltage by the current detection resistor 22 connected in series with the solenoid 26, and the resistor 20 and the resistor 2 are connected.
The bias voltage determined by 1 is applied to become the drive current feedback voltage V _I , which is input to the other input terminal of the comparator 19.

The comparator 19 turns on / off the power switching element 25 by the output that is switched by comparing the H point voltage V _H and the drive current feedback voltage V _I. The on / off control of this solenoid drive current is V _H >
If V _I , the power switching element 25 is turned on,
While increasing the solenoid drive current, if V _H <V _I , the power switching element 25 is turned off, and the solenoid drive current is decreased. Changes in the drive current feedback voltage V _I during this period are represented by s-
Shown in t to u.

Since the maximum value V _HH of the H point voltage V _H is set to be larger than the maximum value V _IH of the drive current feedback voltage V _I , when the solenoid 26 is continuously energized, as shown in FIG. As indicated by u to v, the power switching element 25 is held in the ON state, and the life of the power switching 25 is extended and the solenoid driving noise is reduced.

Further, since the transient voltage generated by the solenoid 26 when the power switching element 25 is turned off is absorbed by the flywheel diode 27, it adversely affects other devices connected to this device. There is no.

Now, when the switching signal voltage to the input terminals 9a and 9b is turned off, the capacitor 2 is quickly discharged with the _first time constant t ₁ , so that the voltage V _{B at} point _B is from c to d in FIG. 5B.
As shown in (3), the voltage rapidly decreases, and the voltage at point _D V _D also decreases.

In this way, when V _B <V _C , the comparator 8 is turned off, the G point voltage V _G rises as shown by l to k in FIG. The G point voltage V _G is applied to the input H point voltage V _H instead of the D point voltage V _D.

On the other hand, the voltage V E at the point _E is affected by the action of the buffer 15 and the backflow preventing diodes 9 and 13, and the variable resistance 1
Through 0 and the resistor 5, as shown in g to h of FIG. 5E, it gradually decreases at a time constant t ₂ .

As a result, the H-point voltage V _H becomes p
As shown in q to r, the switching signal voltage once decreases at the same time, and then the second time constant t as shown in q to r in FIG. 5H.
It gradually decreases at ₂ . In addition, the drive current feedback voltage V _I also varies from v to w in FIG. 5I according to the H point voltage V _H.
˜x.

Since the point G voltage V _G can be adjusted by the variable resistor 12, the dead time from the switching signal voltage OFF to the start of the flow rate decrease, which changes depending on the hydraulic pressure line characteristics, can be calculated by, for example, broken lines p to q'in FIG. ~ R can be adjusted to be a solid line pqr.

Further, as shown in FIG. 5I, the H point voltage V _H
Since the minimum voltage V _HL is set to be smaller than the drive current feedback voltage V _I , when the switching signal voltage is off, the power switching element 25 is held in the off state and the solenoid 26 is not energized.

Next, the overall operation will be described.

When a stepwise switching signal voltage V _A is input to the solenoid drive current control device of the present invention, the solenoid drive current does not change stepwise due to the above-mentioned principle, but increases over time t ₁ , After that, it gradually increases over time t ₂ .

Therefore, the attraction force of the solenoid 26 is prevented from rapidly increasing, but the attraction force of the solenoid 26 when the time t ₁ (first time constant) set by the first time constant circuit has elapsed is As described above, the spring force of the valve is set to the same value as the maximum value of the spring force at the valve opening start position in consideration of the tolerance of the valve components, as shown in FIG. 6C. Even if it is large, the dead time from the input of the switching signal voltage V _{A to} the beginning of the flow of the fluid passing through the valve can be suppressed within the time t ₁ at the maximum.

On the other hand, as shown in FIG. 6 (d), even when the spring force of the valve is small, the suction force of the solenoid 26 gradually increases, so the spool acceleration at the valve opening start position is gentle and the solenoid valve The dead zone does not go too far, the increase in the initial flow rate can be reduced, and the shock at the initial stage of switching can be suppressed.

As described above, according to the present invention, the delay of the valve operation at the time of switching due to the tolerance of the individual component parts of the valve is
In addition to being suppressed within a time t ₁ at the maximum, a sharp increase in the flow rate at the time of switching due to the tolerance of the components of the individual valves is also suppressed, and a shock at the time of switching can be appropriately prevented.

Further, as shown in FIG. 7A, when the switching signal voltage fluctuates and becomes large, FIG.
The current value at the point t of
5I increases, but the increase rate of the suction force until reaching point t in FIG. 5I is gradual, so the spool acceleration at the valve opening start position is gradual, and the increase in the initial flow rate can be reduced.

On the other hand, as shown in FIG. 7B, when the switching signal voltage becomes small, the attracting force of the solenoid 26 decreases because the current value at the point t in FIG. 5I decreases. Since the attraction force of the solenoid 26 at the point t in FIG. 5I is set to a large value in consideration of the tolerances and combinations of the components, the decrease in the attraction force of the solenoid 26 does not increase the dead time until the flow starts. can do.

As described above, according to the present invention, since the fluctuation amount of the solenoid attraction force can be suppressed to be small with respect to the fluctuation of the switching signal voltage, the valve operation delay and the initial flow rate caused by the fluctuation of the switching signal voltage can be suppressed. It is possible to properly suppress the rapid increase in

Further, in the present invention, in order to obtain the above operation, no special adjusting parts such as a variable resistor are required, so that it is possible to reduce the cost by reducing the adjusting man-hour, and the handling is easy and the productivity is high. In addition, the electrical box for mounting the solenoid valve does not become large.

FIG. 8 shows another embodiment of the present invention, in which the fixed resistor 16 of the circuit of FIG. 2 is changed to a variable resistor 36.

According to this embodiment, since the variable resistor 36 can change the voltage at the point n in FIG. 5H, the exciting current of the solenoid at the point t in FIG. The solenoid attraction force characteristic between s and t can be appropriately adjusted.

Therefore, the same exciting current control device can deal with different dead zones by the individual solenoid valves, and even if the spring built in the solenoid valve or the dead zone is changed, the same exciting current is applied. It can be handled by a control device.

FIG. 9 shows still another embodiment of the present invention, in which the comparator 30 and the variable resistor 3 are added to the circuit of FIG.
1 and a backflow prevention diode 29 are added.

According to this, by the functions of the backflow prevention diode 29 and the comparator 30, the capacitor 14 is charged with the time constant by the combination with the variable resistor 10 when the switching signal voltage is turned on, and when the switching signal voltage is turned off. And the resistor 7 are combined to be discharged. As a result, when the switching signal is turned on and when the switching signal is turned off, the exciting current of the solenoid can be controlled with different time constants.

[0064]

According to the first aspect of the invention, when the stepwise switching signal voltage V _A is input, the solenoid drive current does not change stepwise, and the time t ₁ (first time constant) is applied. And then gradually increases over time t ₂ (second time constant). Therefore, by appropriately adjusting the suction force of the solenoid when time t ₁ elapses, the configuration of each valve is increased. The delay in valve operation at the time of switching due to the tolerance of the parts is suppressed within a time t ₁ at the maximum, and the rapid increase in the flow rate at the time of switching due to the tolerance of the component parts of the individual valves is also suppressed. , The shock at the time of switching can be properly prevented, and the fluctuation amount of the solenoid attraction force can be suppressed to a small amount even when the switching signal voltage fluctuates. Rapid flow rate Pressurized can be appropriately suppressed. Also, because this does not require special adjustment parts such as variable resistors, cost can be reduced by reducing the adjustment man-hours, handling is easy and productivity is improved, and the electrical box for mounting the solenoid valve is also available. Does not become large.

According to the second invention, the flywheel diode absorbs the transient voltage excited by the solenoid when the power switching element is turned off.
There is no adverse effect on other devices connected to this device.

According to the third invention, since the time constant of the first time constant circuit can be set to an arbitrary value, an appropriate value can be set as the first time constant.

According to the fourth invention, since the time constant of the second time constant circuit can be adjusted to an arbitrary value, an appropriate value can be set as the second time constant.

According to the fifth invention, the second reference voltage can be adjusted to an arbitrary value, so that an appropriate value can be set as the second reference voltage.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of the same.

FIG. 3 is a circuit diagram showing a first time constant circuit of the same.

FIG. 4 is a circuit diagram showing a second time constant circuit of the same.

FIG. 5 is a characteristic diagram similarly showing a voltage change at each point of the circuit.

FIG. 6 is a characteristic diagram similarly showing a voltage change at a point I of the circuit and a flow rate change passing through the solenoid valve.

FIG. 7 is a characteristic diagram similarly showing a voltage change at a point I of the circuit and a flow rate change passing through the solenoid valve.

FIG. 8 is a circuit diagram showing another embodiment of the present invention.

FIG. 9 is a circuit diagram showing another embodiment of the invention.

FIG. 10 is a circuit diagram showing a conventional example.

FIG. 11 is a characteristic diagram showing a voltage change at a specific point of the circuit of the conventional example.

FIG. 12 is a characteristic diagram similarly showing a voltage change at a point K of the circuit and a flow rate change passing through the solenoid valve.

FIG. 13 is a characteristic diagram similarly showing a voltage change at a point K of the circuit and a flow rate change passing through the solenoid valve.

[Explanation of symbols]

 101 Solenoid 102 First Time Constant Circuit 103 Second Time Constant Circuit 104 First Reference Voltage 105 Second Reference Voltage 106 First Comparator 107 First Backflow Prevention Diode 108 First Adder 109 Detection Resistor 110 Third Reference Voltage 111 Second Adder 112 Second Backflow Prevention Diode 113 Second Comparator 114 Power Switching Element 115 Flywheel Diode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Jun Kugenuma 2-4-1, Hamamatsu-cho, Minato-ku, Tokyo World Trade Center Building Kayaba Industry Co., Ltd. (72) Inventor Haruhiko Kawasaki, Hamamatsu-cho, Minato-ku, Tokyo 4-1-1 World Trade Center Building Kayaba Industry Co., Ltd.

Claims (5)

[Claims] 1. A solenoid excitation current controller for controlling on / off of an excitation current flowing through a solenoid, comprising: a first time constant circuit for changing an input signal with a first time constant; and an output of the first time constant circuit. A second time constant circuit for changing the output of the first time constant circuit by a second time constant, and a first comparator that outputs a second reference voltage by comparing the output of the first time constant circuit with a first reference voltage. A first adder for adding the output of the first time constant circuit after passing through the first backflow prevention diode and the output of the second time constant circuit, and converting the drive current of the solenoid into a voltage A detection resistor; a second adder for adding an output from the detection resistor and a third reference voltage; and an output of the first adder for the second reference after passing through a second backflow prevention diode. The added value obtained by adding the voltage and the second value
A second comparator for comparing the output of the adder of 1. and a power switching element which is on / off controlled by the output of the second comparator. 2. The exciting current control device for a solenoid according to claim 1, further comprising a flywheel diode that absorbs a transient voltage generated from the solenoid when the power switching element is turned off. 3. The exciting current control device for a solenoid according to claim 1, wherein the first time constant circuit can set its time constant to an arbitrary value. 4. The exciting current control device for a solenoid according to claim 1, wherein the second time constant circuit includes a variable resistor capable of adjusting the time constant to an arbitrary value. 5. The exciting current control device for a solenoid according to claim 1, further comprising a variable resistor for adjusting the second reference voltage to an arbitrary value.