JPH0257775A - Solenoid valve with lift sensor - Google Patents

Abstract

PURPOSE:To prevent the mag. flux generated as leakage at a side gap from influencing a lift sensor by forming side gap of a solenoid valve magnetic circuit on the side apart farther from the lift sensor than the main gap. CONSTITUTION:With a main gap 9 and a side gap 10 interposed, a plunger 8 is installed in the magnetic circuit of a solenoid valve 1 equipped with a lift sensor 3. This plunger 8 fitted with a valve body 12 is attracted to the main gap 9 side by current supply to a solenoid 4. Therein the side gap 10 of the above-mentioned magnetic circuit is formed on the side apart farther from the lift sensor 3 than the main gap 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a solenoid valve with a lift sensor that is equipped with a lift sensor that detects the amount of lift of a valve body.

[Prior Art] Conventionally, there are some electromagnetic valves that are equipped with a potentiometer to detect the amount of lift of the valve body of the electromagnetic valve.

However, a potentiometer has a slider that slides on a resistor, and if the potentiometer is used in a manner that increases the number of operations, wear powder may be generated, and as a result, an abnormal value may be output.

For this reason, as shown in FIG.
G has been devised.

This solenoid valve 10G includes a yoke 103, a stator core 104, a main gap 105, a
, a plunger 106, and a side gap 107. The plunger 106 is connected to a shaft 108.
It is provided so as to be movable in the axial direction.

A valve body 110 that opens and closes the fluid passage 109 is provided at the lower end of the shaft 108. The valve body 110 opens the fluid passage 109 when the plunger 106 is attracted to the stator core 104 by energizing the electromagnetic coil 102.
Open.

The actuating transformer type lift sensor 101 has a -order coil 1
11 and the secondary coil 112, a magnetic body 113 provided at the upper end of the shaft 108 is displaced in accordance with the movement of the plunger 106, thereby generating an output voltage and discharging the valve body 11.
This is to detect a lift amount of 0.

[Problems to be Solved by the Invention] However, in the solenoid valve 100 with a lift sensor as described above, when the magnetic flux passing through the magnetic circuit leaks from the side gap 107 and affects the lift sensor 101, causing a problem in the sensor output. There is.

In such a case, a seal member may be provided between the yoke 103 and the plunger 106 to prevent leakage of magnetic flux, but this increases the manufacturing cost of the solenoid valve 100 and prevents the magnetic flux from escaping to the seal member. Therefore, the attraction force of the solenoid valve 100 decreases, and the characteristics of the solenoid valve 100 change accordingly.

The present invention has been made in view of the above circumstances, and its purpose is to provide a solenoid valve with a lift sensor that prevents the influence of magnetic flux due to the drive current of the solenoid valve on the lift sensor without increasing manufacturing costs. It is in.

[Means for Solving the Problems] In order to achieve the above object, the present invention has a plunger disposed in a magnetic circuit of an electromagnetic coil via a main gap and a side gap. A solenoid valve that drives a valve body provided to interlock with the plunger by being attracted to the main gap side; The magnetic circuit of the electromagnetic coil includes a lift sensor that detects a lift amount, and the magnetic circuit of the electromagnetic coil includes:
The technical means is that the side gap is formed on a side farther from the lift sensor than the main gap.

[Actions and Effects of the Invention] The present invention having the above configuration has the following effects in the main gap and side gap formed in the magnetic circuit of the electromagnetic coil:
The side gap is formed on the side farther away from the lift sensor mounted on the solenoid valve than the main gap.

As a result, even if the magnetic flux generated by energizing the electromagnetic coil leaks from the side gap, the influence on the lift sensor can be reduced, and a stable output from the lift sensor can therefore be obtained.

In addition, in the case of the present invention, since a seal member is not used to prevent magnetic flux leakage, and the structure is not complicated, the magnetic flux to the lift sensor can be transmitted without increasing the manufacturing cost of the solenoid valve. The impact can be reduced.

[Example] Next, an example of the electromagnetic valve with a lift sensor of the present invention will be described based on the drawings.

FIG. 1 is a sectional view of a solenoid valve with a lift sensor.

The electromagnetic valve 1 with a lift sensor of the present embodiment has an actuating transformer type lift sensor (hereinafter referred to as a lift sensor) 3 mounted on the L portion (upper part of FIG. 1) of the electromagnetic valve 2.

The electromagnetic valve 2 has a ferromagnetic yoke 5 and a stator core 6 arranged around an electromagnetic coil 4 wound around a bobbin 4a, and a shaft 7 disposed in the center of the electromagnetic coil 4. A connected plunger 8 is provided so as to be movable in the axial direction.

The yoke 5 is formed to cover the outer periphery and bottom side of the electromagnetic coil 4 in FIG. It is formed to cover about the upper half of the section.

The plunger 8 is disposed in about a half space below the inner circumference of the electromagnetic coil 4, with a main gap 9 and a side gap 10 between it and the stator core 6.

As a result, a magnetic circuit consisting of the yoke 5, stator core 6, main gap 9, plunger 8, and side gap 10 is formed around the electromagnetic coil 4, and the magnetomotive force generated in the magnetic circuit by energizing the electromagnetic coil 4 causes the plunger 8 is attracted to the stator core 6 side (the negative side in FIG. 1).

In the magnetic circuit of this electromagnetic coil 4, a side gap 10
is formed on the side farther away from the lift sensor 3 mounted on the solenoid valve 2 than the main gap 9.

A valve body 12 is provided at the lower end of the shaft 7 to open and close the fluid passage 11 according to the movement of the plunger 8.

This valve body 12 has a valve seat 14 in order to reliably close the fluid passage 11 when the electromagnetic coil 4 is not energized by a compression spring 13 provided between the plunger 8 and the stator core 6 facing each other via the main gap 9. is being held down. Therefore, when the electromagnetic coil 4 is energized, the plunger 8 is attracted toward the stator core 6 against the elastic force of the compression spring 13.

The lift sensor 3 is mounted on the upper part of the stator core 6 of the solenoid valve 2, and is housed in a resin (for example, plastic) housing 15.
A through hole 16 into which the upper end of the shaft 7 of the electromagnetic valve 2 is inserted is provided at the center of the bottom.

A cylindrical sensing element 11 configured by combining a primary coil 17a and a secondary coil 17b is provided inside the housing 15, and the hollow part of the sensing element 17 is connected to a magnetic material provided at the upper end of the shaft 7. 18 is provided so as to be displaced up and down in accordance with the movement of the plunger 8.

The sensing element 17 is electrically connected to a circuit board 19 for converting a magnetic signal into an electric signal and outputting it, and outputs the signal through an output terminal 21 provided on a connection connector 20 together with an input 6 terminal and a ground terminal. Ru.

The inside of the housing 15 is covered with a shield case 22 made of iron to block the influence of external magnetic fields, and the upper part of the housing 15 is similarly covered with a shield cover 23 made of iron.

Next, the operation of the lift sensor equipped solenoid valve 1 of this embodiment will be explained.

When the electromagnetic coil 4 is energized, a magnetomotive force is generated in the magnetic circuit constituted by the yoke 5, stator core 6, main gap 9, plunger 8, and side gap 10, and the 7-lunger 8 resists the elastic force of the compression spring 13. and is attracted to the stator core 6 side.

As a result, the shaft 7 connected to the plunger 8 and the valve body 12 provided at the lower end of the shaft 7 operate in conjunction with the plunger 8, and the valve body 12 moves away from the valve seat 14 to open the fluid passage 11.

At this time, the magnetic body 18 provided at the upper end of the shaft 7
By displacing within the sensing element 17, the current flowing to the primary coil 17a via the input terminal changes, and the magnetic flux interlinking to the secondary coil 17b changes.

As a result, an induced voltage corresponding to the amount of displacement of the plunger 8 is generated in the secondary coil 17b, and is output from the output terminal 21.

Since the plunger 8 is interlocked with the valve body 12 via the shaft 7, the amount of lift of the valve body 12 can be detected by detecting the induced voltage according to the amount of displacement of the plunger 8.

In this way, in the lift sensor equipped solenoid valve 1 of this embodiment,
In the magnetic circuit of the electromagnetic coil 4, the side gap 10
By forming the main gap 9 on the side farther from the lift sensor 3, the influence of the magnetic flux leaking from the side gap 10 on the lift sensor 3 can be reduced.

Therefore, it is possible to prevent the leaked magnetic flux from interfering with the sensor output of the lift sensor 3, and it is possible to obtain a stable output.

Further, in the case of the present invention, there is no need to use a sealing member to prevent leakage of magnetic flux, and there is no need to complicate the structure. The impact of this can be reduced.

(Modified example) In this embodiment, an actuating transformer type lift sensor 3 was used to detect the lift amount of the valve body 12, but a magnetic sensor such as a pole element or an MRE element (magnetic resistance element) may also be used. Lift sensor 3 may also be used.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the solenoid valve with a lift sensor of the present invention, Fig.
The figure is a cross-sectional view of a solenoid valve with a lift sensor, which shows an example of the prior art. In the diagram

Claims (1)

[Claims] 1) (a) A plunger disposed in a magnetic circuit of an electromagnetic coil via a main gap and a side gap,
(b) a solenoid valve that is attracted to the main gap side by energizing the solenoid coil to drive a valve body provided to interlock with the plunger; (b) a magnetic valve mounted on the solenoid valve; a lift sensor that detects the lift amount of the valve body by converting a signal into an electric signal, and the magnetic circuit of the electromagnetic coil is configured such that the side gap is formed on a side farther from the lift sensor than the main gap. A solenoid valve with a lift sensor.