JPH0257773A - Solenoid valve with lift sensor - Google Patents

Abstract

PURPOSE:To eliminate sliding parts in the axial direction and prevent generation of abrasion dust due to slide by specifying the gap between a housing and a shaft and the gap between a sensing element and a core. CONSTITUTION:A solenoid valve 1 is equipped with a lift sensor 3 to sense the amount of lift of a valve body by converting magnetic signals into electrical signals. The shaft 7 of this solenoid valve 1 is borne by resilient member such as leaf springs 8, 9 with displaceability in the axial direction. Therein the gap between a housing 4 and the shaft 7 and that between a sensing element 22 as fixation part for the lift sensor 3 and a core 10 are set no less than 0.3mm.

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] For example, Japanese Unexamined Patent Publication No. 16209/1983 discloses a potentiometer attached to an electromagnetic proportional valve to perform feedback control of the position of one lunge of the electromagnetic proportional valve.

This electromagnetic proportional control valve constantly vibrates slightly to control the valve opening, and when used for engine air-fuel ratio control or idle rotation speed control, for example, it operates more than 10 billion times in total. A high degree of reliability is required because the number of vibrations reaches a certain number of vibrations.

In a potentiometer, a slider provided to interlock with a plunger of an electromagnetic proportional control valve slides on a resistor in order to detect the position of a plunger that drives a valve body and perform feedback control.

[Problem to be solved by the invention] However, since the bearings and valve parts of electromagnetic proportional control valves are sliding types, the sliding parts may become immobile due to foreign matter entering the sliding parts or abrasion particles during operation. In addition, since a potentiometer has a slider that slides on a resistor, if the potentiometer is used in a way that involves a large number of operations, wear particles may be generated, and as a result, an abnormal value may be output. be.

As a result, high reliability is required for the engine's air-fuel ratio control and idle rotation speed control as described above, and when used in places where the number of operations is high, reliability becomes lower as the number of operations increases. The problem was a decline in sexual performance.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a solenoid valve with a lift sensor that can ensure a high degree of reliability even when the number of operations is increased.

[Means for Solving the Problems] In order to achieve the above object, the present invention is attached to a shaft and disposed within a magnetic circuit of an electromagnetic coil, and is attracted by energization to the electromagnetic coil and is attached to the shaft. Equipped with a moving core that displaces in the axial direction,
A solenoid valve that opens and closes a fluid passage by a valve body interlocking with the moving core, and a lift sensor that is mounted on the solenoid valve and detects the lift amount of the valve body by converting a magnetic signal into an electric signal, The shaft is supported at at least two points by elastic members and is displaceable in the axial direction. The technical means is to set the gap to 0.3u or more.

[Operations and Effects of the Invention] The present invention having the above-mentioned configuration supports the shaft to which the moving core is attached by an elastic member so that it can be displaced in the axial direction. type bearings can be omitted.

In addition, by setting the gap between the fixed part of the solenoid valve and lift sensor and the movable part such as the shaft or moving core that is displaced in the axial direction between the fixed parts to 0.3 ms or more, The sliding part can be eliminated.

As a result, the generation of abrasion powder due to sliding is eliminated, and even if foreign matter enters the gap between the fixed part and the movable part, the movable parts such as the shaft and moving core are prevented from sticking due to foreign matter. Therefore, the reliability does not decrease even if the number of operations is increased. Therefore, a high degree of reliability is required and it can be used in places where the number of operations is large.

[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 lift sensor equipped solenoid valve 1 used for idle rotation speed control.

The solenoid valve 1 with a lift sensor of this embodiment is equipped with an actuating transformer-type lift sensor (hereinafter referred to as lift sensor) 3 on the upper part of the electromagnetic proportional control valve 2 (upper part of FIG. 1), and a throttle valve (not shown) is installed. The idle speed is controlled by changing the amount of air bypassed.

In the electromagnetic proportional control valve 2, a stator core 6 made of a ferromagnetic material is arranged so as to cover the upper side and the upper side 273 of the inner peripheral part of the electromagnetic coil 5 disposed in the housing 4, and the stator core 6 is disposed in the center of the stator core 6. A shaft 7 made of a non-magnetic material is provided extending from the top to the bottom inside the housing 4 through the housing 4 .

The shaft 7 is supported at two points by leaf springs (elastic members of the present invention) 8 and 9 fixed to the inner wall of the housing 4, and is displaceable in the axial direction without sliding.

A moving core 10 made of ferromagnetic material that is attracted toward the stator core θ side by the magnetomotive force generated in the magnetic circuit when the electromagnetic coil 5 is energized has an air gap between it and the lower end of the stator core 6. installed.

At the lower end of the shaft 7, a pressure balance bellows (hereinafter abbreviated as bellows) 13 is integrally formed with a valve (valve body of the present invention) 12 for opening and closing an air passage (fluid passage of the present invention) 11. installed.

This bellows 13 has a flange portion 13 formed at the upper end.
a is fixed to the inner wall of the housing 4, the center part of the valve 12 is fitted to the lower end of the shaft 7, and a spring 14 is applied to the shaft 7 from below the valve 12.
is pressed against the flange portion 7a.

Note that the valve 12 has a pressure inlet 12 of the bellows 13.
A is provided.

As shown in FIG. 2, the leaf spring 8.9 has annularly formed attachment parts 8a, 9a, and a support part 8b formed so that a part of the attachment parts 8a, 9a extends toward the center. , 9b
It consists of a number shaft 7 at the tip of the support parts 8b and 9b.
An insertion hole 8C19C is provided for inserting the.

The leaf spring 8 is attached to the shaft 7 at a position above the stator core 6.
The mounting portion 8a is fixed to the inner wall of the housing 4 by an annular collar 15, and the support portion 8a
The distal end portion of b is fixed to the flange portion 7b of the shaft 7 by a collar 16 fitted onto the shaft 7.

The leaf spring 9 is connected to the shaft 7 at the lower end of the moving core 10.
, and the mounting portion 9a is attached to the flange portion 13 of the bellows 13.
is fixed to the inner wall of the housing 4 by a,
The tip of the support portion 9b is attached to the lower end of the moving core 10 attached to the shaft 7 and the flange portion 7C of the shaft 7
It is fixed between.

A part of the collar 16 fitted to the shaft 1 includes
A spring 17 is provided that provides the shaft 7 and the moving core 10 with an attractive force and a repulsive force when the moving core 10 is attracted toward the stator core 6 by energizing the electromagnetic coil 5.

Therefore, when the electromagnetic coil 5 is not energized, the valve 12 is moved to the valve seat 1 in order to completely enclose the air passage 11.
A biasing force of a spring 17 acts on the shaft 7 so as to press it against the shaft 8.

As shown in FIG. 3, this electromagnetic proportional control valve 2 is connected to the 0N
- The moving core 10 is controlled by the OFF ratio signal (duty signal) and generated between the stator core 6 and the moving core 10 according to the magnitude of the current flowing through the electromagnetic coil 5, and the moving core 10 is moved to the spring 14, spring 11, and is attracted to the stator core 6 side to a position balanced with the axial spring force of the leaf spring 8.9.

The clearance between the valve 12 and the valve seat 18 changes depending on the amount of displacement of the moving core 10 in the axial direction, and the flow rate of air flowing from the inflow boat 20 to the outflow boat 21 is controlled.

The current flowing through the electromagnetic coil 5 has a sawtooth waveform as shown in FIG. 4, and the moving core 10 repeatedly vibrates in response to this waveform.

Note that the inflow boat 20 is connected to an air cleaner (not shown) via a bypass passage (not shown) that bypasses the throttle valve, and the outflow boat 21 is connected to an air cleaner (not shown) through a bypass passage (not shown) that bypasses the throttle valve.
It is connected to a surge tank (not shown) provided downstream of the throttle valve.

The lift sensor 3 includes a secondary coil 22a and a secondary coil 22.
Cylindrical sensing element 2 configured by combining b.
2, a magnetic core 23 provided at the upper end of the shaft 7 is disposed so as to be displaced up and down according to the movement of the moving core 10, and the coil inductance that changes due to the displacement of the core 23 is connected to a bridge circuit. This converts the voltage into a voltage change and outputs it.

The electromagnetic proportional control valve 2 and the lift sensor 3 described above include the housing 4, the stator core 6, and the sensing element 7-22, which are the fixed parts of the present invention, and the shaft 7, the moving core 10, and the core, which are the movable parts of the present invention. 23, the gap between the housing 4 and the moving core 10, the gap between the stator core 6 and the shaft 7, the gap between the housing 4 and the shaft 7, and the gap between the sensing element 22 and the core 2.
3 (indicated by symbols A, B, C, and D in Figure 1) is 0.
．． It is set to 311 or higher.

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

The electromagnetic coil 5 is energized according to the current value controlled by the 0N-Or'F ratio signal of the CPU 19, and a magnetomotive force is generated in the magnetic circuit of the electromagnetic coil 5.

The moving core 10 is attracted to the stator core 6 side until the position where the magnetomotive force generated in the magnetic circuit is balanced with the axial spring forces of the spring 14, the spring 17, and the leaf spring 8.9, and from then on, as shown in FIG. Repeats slight vibrations in response to the current waveform.

Due to the displacement of the moving core 10, the valve 12 provided at the lower end of the shaft 7 changes the clearance with the valve seat 18 according to the amount of movement of the moving core 10, and air flows from the inflow port 20 to the outflow bows 1 to 21. Regulate distribution.

At this time, in the lift sensor 3, the core 23 provided at the upper end of the shaft 7 displaces within the sensing element 22 in conjunction with the moving core 10, so that the valve 12
Converts the lift amount into a voltage change and outputs it.

In the above operation, the shaft 7, which is displaced in the axial direction together with the moving core 10, is supported at two points by leaf springs 8 and 9 without using a conventional sliding type bearing, and is non-sliding. Displaceable.

Also, there are gaps between the housing 4 and the moving core 10 (marked A in FIG. 1), gaps between the stator core 6 and the shaft 7 (marked B in FIG. 1), and gaps between the housing 4 and the shaft 7 (marked B in FIG. 1). 1), and the gap between the sensing element 22 and the core 23 (sign D in Figure 1) are each 0.3u.
By setting the following, even slight vibrations of the moving core 10 will not cause wear between the fixed part and the movable part of the present invention, and a high degree of reliability can be maintained even if the number of operations is increased. Can be done.

As in this embodiment, when the electromagnetic proportional control valve 2 is used to control the idle speed of the engine, carbon blown back from the engine or dust coming in from the air cleaner passes through the pressure inlet 12a of the bellows 13. Even if a person enters between the fixed part and the movable part, as mentioned above, keep the gap between the fixed part and the movable part to 0.3+u+.
By setting -, the moving core 10, shaft 7, etc. will not stick.

In this way, by making the moving parts such as the moving core 10, shaft 7, and core 23 completely non-sliding,
The electromagnetic proportional control valve 2 can be used in locations where a high degree of reliability is required even when the number of operations is increased.

(Modification) In this embodiment, the actuating transformer type lift sensor 3 was used to detect the lift amount of the valve 12, but a lift sensor using a magnetic sensor such as a Hall element or an MRE element (magneto-resistive element) 3 is also fine.

Two points of the shaft 7 were supported by leaf springs 8.9,
It may be supported by 2 or more points.

Moreover, although the leaf spring 8.9 is illustrated as an example of the elastic member, it is not necessary to limit the elastic member to a leaf spring.

Although the lift sensor-equipped solenoid valve 1 of the present invention is used for idle rotation speed control, it may also be used for engine air-fuel ratio control.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the electromagnetic proportional control valve with a lift sensor of the present invention, Fig. 2 is a plan view of the leaf spring, Fig. 3 is a drive circuit diagram of the electromagnetic proportional control valve, and Fig. 4 is the current flowing through the electromagnetic coil. FIG. 3 is a current waveform diagram showing an example of a waveform. In the diagram

Claims (1)

[Claims] 1) (a) A moving core is attached to the shaft and disposed within the magnetic circuit of the electromagnetic coil, and is attracted by energization of the electromagnetic coil and displaced in the axial direction together with the shaft. (b) a solenoid valve that opens and closes a fluid passage using a valve body interlocking with the moving core; (b) a lift mounted on the solenoid valve that detects the lift amount of the valve body by converting a magnetic signal into an electric signal; and a sensor, the shaft is supported at at least two points by elastic members and displaceable in the axial direction, and the shaft is displaceable in the axial direction between a fixed part of the electromagnetic valve and the lift sensor and the fixed part. A solenoid valve with a lift sensor, characterized in that a clearance between the moving part and the moving part is set to 0.3 mm or more.