JPH01316584A - Solenoid changeover valve - Google Patents

Abstract

PURPOSE:To detect he operation of a spool, that's, the operation of a solenoid changeover valve accurately by indirectly detecting AC exciting voltage to a coil by means of a current sensor and recognizing the predetermined position of a movable core. CONSTITUTION:AC exciting voltage to the coil 4 of a solenoid changeover valve is transmitted into a primary conductor 6. A current sensor 7 outputs an induced voltage due to magnetic flux generated from the primary conductor 6. Then, the output voltage passes through a detection circuit 8 so that the predetermined position of a movable core 16 can be recognized.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention applies, for example, to AC excitation of a coil in a solenoid section attached to a valve body! The present invention relates to an electromagnetic switching valve that operates a spool that switches a fluid flow path, particularly to detecting the operation of an electromagnetic switching valve based on the operation of a movable iron core.

[Prior Art] Fig. 6 shows, for example, a cross-sectional view of a conventional electromagnetic switching valve, in which 1 is a valve body that switches a fluid flow path, 2 is an electrical box to which a cable for supplying an electric signal from the outside is connected; 1 is a solenoid part housed in a synthetic resin case, 4 is a coil, 5 is a coil frame made of silicon steel with high magnetic permeability and low core loss, 9 is a terminal plate, 10 is a plug, 11 is a receptacle, 12 is a spool that switches the flow path in response to the excitation of the coil 4; 13 is a spring; 14 is a fixed core; 15 is a bushing pin connected to the spool 12; 16 is a movable core that is activated by the excitation of the coil 4; 17 is a display light, 25
2 is a microswitch that is activated by being pressed by the spool 12, and 26 is a case attached to the valve body 1.

A conventional electromagnetic switching valve is constructed as described above, and in order to excite the coil 4 of the solenoid section 3 attached to the valve body 1 with alternating current, the electromagnetic switching valve has an electrical equipment box in which a cable is placed on the valve body 1 from the outside. It is connected to the terminal plate 9 of No. 2, and power is supplied to the coil 4 through the plug 10 and receptacle 11. When the coil 4 is excited with alternating current, shading is applied to prevent whirring, the movable iron core 16 is attracted to the fixed iron core 14, and the spool 1
2 is activated.

The operation indication of conventional solenoid switching valves is coil 4 of the renoid component.
An indicator light 17 is provided on the terminal board 9 to indicate the AC voltage applied to the terminal board 9. However, in the above method, even if an AC voltage is applied to the terminal plate 9, it cannot be confirmed that the coil 4 is actually excited and the electromagnetic switching valve operates correctly.

Therefore, in order to check the operation when AC voltage is applied to the coil 4 of the electromagnetic switching valve, a micro switch 25 and a cover 26 are provided in place of the renoid parts on one side of the valve body 1, and a bushing pin 15 is connected to the end of the spool 12. to engage the microswitch 25. The spool 12 is actuated by the attractive force based on the magnetic field generated when the coil 4 is excited with alternating current, and the connected bushing pin 15 is connected to the micro switch 2.
5 is pressed to activate it, the responsive contact signal is transmitted to the electrical equipment box 2, and an indicator light 17 indicates the operation.

When the excitation of the coil 4 is stopped, the spool 12 becomes the spring 1
It is restored by the spring force of step 3.

Further, in the above operation, the strokes required to operate the spool 12 and the microswitch 25 must be matched.

[Problems to be Solved by the Invention] In the conventional electromagnetic switching valve as described above, its operation is indicated by the lighting of the indicator light 17 provided on the terminal plate 8 when the AC excitation voltage is applied to the coil 4 of the solenoid component. It is being done. However, the AC excitation voltage supplied from the terminal board 8 may not be able to properly excite the coil 4 due to poor connections during the wiring process or breakage of the coil 4, or the spool 12 may become stuck due to foreign matter mixed into the hydraulic oil. The spool 12 may not operate properly.

When the microswitch 25 is installed in the valve body 1, the size of the electromagnetic switching valve increases and the area occupied for installation increases.

The spool 12 is required to have sufficient torque and stroke consistency to mechanically engage and press the microswitch 25, thereby affecting the operation of the electromagnetic switching valve.

Furthermore, since the solenoid component is attached to only one side of the valve body 1, there is a problem in that switching control of the electromagnetic switching valve is limited from three positions to two positions.

This invention was made to solve this problem, and the electromagnetic switching valve is capable of generating an induced voltage in response to the coil excitation current caused by the operation of the movable core of the electromagnetic switching valve, without being affected by its original operation or dimensions. An object of the present invention is to obtain an electromagnetic switching valve that can correctly detect a predetermined switching operation by using a current sensor that outputs .

[Means for Solving the Problems] The electromagnetic switching valve according to the present invention includes a primary conductor that transmits an applied AC excitation voltage to a coil, and a current sensor that outputs an induced voltage by linking with the magnetic flux generated by the primary conductor. A detection circuit is provided for identifying the position of the spool based on the current sensor output and a threshold value corresponding to the current sensor output when the spool responds to a predetermined position.

[Effect].

In this invention, a detection circuit is provided at the output of the current sensor that is sensitive to the excitation current to the coil of the solenoid part related to the operation of the electromagnetic switching valve. Since the induced voltage at a predetermined position of the movable core can be identified by the detection circuit, the operation of the movable core can be detected correctly, and by monitoring the detection circuit output, the correct operation of the electromagnetic switching valve can be confirmed. I can understand it.

The above operation does not require interrupting the coil excitation circuit of the electromagnetic switching valve and providing a current sensor, so even if the current sensor fails, the operation of the electromagnetic switching valve will not be affected. Further, the induced voltage of the current sensor based on the current flowing through the primary conductor can be stabilized even if the ambient temperature changes, so that correct operating data of the electromagnetic switching valve can be obtained.

[Embodiment] An embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
2.13.14.15.16.17 are the same as the above-mentioned conventional electromagnetic switching valve, and 6 is AC excitation to coil 4! 7 is a current sensor having a secondary coil wound around a ring-shaped high permeability magnetic core, and 8 is a detection circuit for detecting the output signal of the current sensor.

In the electromagnetic switching valve configured as described above, a solenoid component is provided on the side of the valve body 1, and an electrical equipment box 2 is placed on the top.

The AC power that controls the operation of the electromagnetic switching valve is supplied from the outside via a cable to the terminal board 9 of the electrical box 2, and is further supplied from the terminal board 9 to the solenoid component using the primary conductor 6 via the plug 10 and receptacle 11. A hollow cylindrical coil 4 is excited.

A fixed iron core 14 is provided in a part of the hollow portion of the coil 4, and a movable iron core 16 that is movable concentrically therewith is arranged. One end of the movable iron core 16 is connected to a spool 12 in the valve body 1 via a bushing pin 15, and the spool 12 is normally placed in a normal position by the force of a spring 13. When the hollow cylindrical coil 4 is excited with alternating current, an alternating magnetic field is generated, and the coil frame 5 is made of silicon steel with high magnetic permeability and low core loss, and the fixed iron core 14 is placed in the hollow part of the coil 4. The movable iron core 16 arranged concentrically therewith forms a magnetic circuit by excitation of the coil 4. The movable core 16 is attracted to the fixed core 14, the spool 12 is operated, and the fluid flow path within the valve body 1 is switched.

At the same time, the magnetic resistance of the magnetic circuit changes, causing a change in the current flowing through the primary conductor 6 connected to the coil 4.

When the excitation of the coil 4 is stopped, the generation of the magnetic field is cut off, and the movable iron core 16, ie, the spool 12, returns to its normal position by the spring force of the spring 13.

When the current sensor 7 made of a ring-shaped high permeability magnetic core is arranged so as to surround the primary conductor 6 which is connected to the terminal plate 9 provided in the electrical equipment box 2 to excite the coil 4, the coil 4 is excited with alternating current. At this time, the excitation current flowing through the primary conductor 6 changes depending on the magnetic resistance of the magnetic circuit, and therefore, an induced voltage is output from the current sensor 7 based on the magnetic resistance depending on the position of the movable iron core 16.

The current sensor 7 is made of a small J method and is input to the detection circuit 7 also provided in the electrical equipment box 2, and also has a threshold value based on the output of the current sensor 7 when the movable core 16 operates and reaches a predetermined position. When the allowable range of the value is determined and similarly inputted to the detection circuit 7, the detection circuit 7 where the output of the current sensor 7 is within the range of the above threshold outputs a predetermined output, and the detection circuit 7 activates the electromagnetic switching valve. It can be detected that this is being done correctly.

If an indicator light 17 is provided at the output of the detection circuit 8 in the electrical equipment box 2, the operation of the electromagnetic switching valve can be appropriately indicated.

In addition, by remotely transmitting the output signal of the detection circuit 8 from the electrical box 2 to the person in charge, proper operating information of the electromagnetic switching valve can be transmitted, and abnormalities in the electromagnetic switching valve can be immediately detected and dealt with early. The switching valve can be maintained in a normal state at all times.

FIG. 2 is a block diagram showing an example of the detection circuit, in which 4.6.7.8.9 are the same as in the above embodiment, and 20 is the first
A comparator, 21 is a second comparator, 22 is a first threshold value E1.23 used in the first comparator 20, a second threshold value E2.24 is an AND circuit, 25 is the i1 extension circuit.

Fig. 3 shows an example of the operation of the detection circuit, in which the solenoid 4 is excited, the alternating current magnetic flux due to the energization of the primary conductor 6 and the secondary coil wound around the magnetic core of the current sensor 7 are linked, and the induced voltage is detected. It is input to circuit 8. The detection circuit 8 includes a first comparator 20 and a second comparator 21 to which the above-mentioned induced voltages are input, and an AND circuit 24. When the output level of exceeds the first threshold E122, the first comparator 2
0, the output is in the on state, and the second comparator 21 receives the second threshold E223 (where E2 > El), constantly generates an output, and the output level of the current sensor 7 reaches the second threshold E2.
23, the output of the second comparator 21 is turned off. Therefore, each output passes through an AND circuit 24 to obtain a logical product output ΔE. When the above logical product output ΔF is engaged with the output of the current sensor 7 at a predetermined position of the spool 12 by the operation of the electromagnetic switching valve through the delay circuit 2'5, and the indicator light 17 is turned on with this signal, the detection circuit 8 outputs. Accordingly, the predetermined operation of the electromagnetic switching valve can be correctly identified.

FIG. 4 shows an example of the transient response of the primary conductor due to the excitation power source. In the electrical equipment box 2, a ring-shaped high permeability magnetic core is arranged so as to surround the primary conductor 6 that supplies the excitation current to the coil 4. When the coil 4 is excited with alternating current, the movable core 16 is actuated by the absorption of the movable core 16 into the fixed core 14, and the induced voltage of the current sensor 7 changes. At the same time, the spool 11 also operates properly and is held in place. The excitation current to this sharpening coil 4 changes due to the magnetic resistance of the magnetic circuit caused by the operation of the movable iron core 16, and is wound around the high permeability magnetic core of the current sensor 7 linked to the magnetic flux generated by the secondary sleeve 6. The induced voltage in the secondary coil exhibits a transient response, and as time passes (after elapsed time to), when the spool 12 is held at a predetermined position, the induced voltage reaches Eo and this state is maintained.

Solenoid switching valves typically have a ratio of maximum current to steady state current that varies significantly, such as 5:1.

FIG. 5 shows an example of the operation of the current sensor, and the current sensor 7
Relationship between ampere turns and induced voltage in the secondary coil of the ring-shaped high-permeability magnetic core due to energization of the primary conductor 6 surrounded by the ring-shaped high-permeability magnetic core or the primary conductor 6 wound around the ring-shaped high-permeability magnetic core. Since the dynamic range of the current sensor 7 includes values of 5 or more, the operation of the electromagnetic switching valve due to the coil excitation current can be correctly detected. The output of the current sensor 7 is applied to the detection circuit 8 as a voltage signal,
By adjusting the first threshold value E122 and the second threshold value E223 to predetermined values and setting the detection range for the operation level EEo, the predetermined operation of the movable iron core 16 can be detected correctly.

When the coil 4 is energized and the movable core 16 does not operate correctly, the magnetic resistance value is different from the predetermined value and the excitation current of the primary conductor 6 is also different, so proper magnetic flux is not detected and the current sensor 7 output is activated. The value is different from the level Eo. Therefore, since it does not match the threshold value of the detection circuit 8 and does not generate a normal output, an abnormality can be detected.

Since the current sensor 1 generates an induced output, even if the temperature rises due to the operation of the electromagnetic switching valve, a stable output can be obtained over a wide range of ambient temperatures.

As described above, since the operation of the movable iron core 16 and the output of the current sensor 7 can correspond to each other, the operation of the electromagnetic switching valve can be accurately grasped by monitoring this output.

The present invention is designed to detect when the spool 12 is stuck in operation due to a poor connection of the solenoid component to the coil 4, disconnection of the coil 4, or foreign matter mixed into the hydraulic oil, in the operation display using the coil excitation voltage of the electromagnetic switching valve. Unlike the electromagnetic switching valve, which may not operate correctly even if voltage is applied and the indicator light 17 lights up, the electromagnetic switching valve is sensitive to the current flowing through the primary conductor 6 in response to the operation of the movable iron core 16 or the spool 12 connected thereto. Since the induced output can be monitored, the switching operation of the flow path by the electromagnetic switching valve can be accurately grasped.

When an abnormality occurs when the excitation of the coil 4 and the induced voltage of the current sensor 7 do not match, information can be quickly communicated using an alarm or an indicator light 17, so that the solenoid switching valve always operates normally. Can be maintained and managed.

[Effect of the invention] As explained above, the present invention operates a solenoid switching valve.
The electromagnetic switching valve has a simple structure in which a current sensor is installed that interlinks with the alternating current magnetic flux generated in the primary conductor when the coil excitation current of the solenoid part is energized, and a detection circuit is attached to the output of the current sensor. An attractive force acts on the movable iron core due to the magnetic flux of the alternating magnetic field, the excitation current of the primary conductor changes, and the current sensor V outputs in response to this, so the current rinser output and the detection circuit output to which the threshold value is applied are monitored. As a result, the operation of the spool, that is, the operation of the electromagnetic switching valve can be detected correctly.

Since the induced voltage of the current sensor can be stabilized over a wide range of ambient temperatures, the above detection operation is performed correctly.

The original operation and dimensions of the solenoid directional valve are not affected in the same way, and any abnormal operation is quickly detected and notified, so the solenoid directional valve can be maintained and managed to always operate normally. be.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a detection circuit, FIG. 3 is an example of the operation of the detection circuit, and FIG. 4 is a diagram showing the excitation of a primary conductor. FIG. 5 is an example of the operation of a current sensor, and FIG. 6 is a sectional view of a conventional electromagnetic switching valve. In the figure, 1 is the valve body, 2 is the electrical box, 1 is the solenoid part, 4 is the coil, 5 is the coil frame, 6 is the primary conductor,
7 is a current sensor, 8 is a detection circuit, 9 is a terminal board, 10 is a plug, 11 is a receptor, 12 is a spool, 13 is a spring, 14 is a fixed iron core, 15 is a bush pin, 16
is a movable iron core, and 17 is an indicator light. Note that the same reference numerals in each figure indicate the same or corresponding parts. Patent applicant: Tokyo Co., Ltd. Instrument tube Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] In an electromagnetic switching valve that applies an AC excitation voltage to the coil of a solenoid attached to the valve body to operate a movable core and switch the fluid flow path, a primary conductor that transmits the applied excitation voltage to the coil of the solenoid; , a current sensor that outputs an induced voltage by interlinking with the magnetic flux generated by the primary conductor, and a detection circuit that identifies a predetermined position of the movable core from the output of the current sensor, and detects the operation of the movable core. An electromagnetic switching valve featuring: