JPH0942906A - Electromagnetic solenoid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic solenoid in which the position of an armature can be known without using a limit switch or a reed switch. SOLUTION: An electromagnetic solenoid 1 composed of an electromagnetic coil 2, a yoke 3 and a stationary core 4 which are magnetized and controlled by an energizing current running through the electromagnetic coil 2, an armature 5 opposed to the stationary core 4, and subjected to a magnetic attracting force by the stationary core 4 so as to be moved coaxially of the core 4, and a spring 8 overcoming the magnetic attracting force between the stationary core 4 and the armature 5, is provided with a detecting means 7 for detecting a variation in the main magnetic flux which varies in dependence with a displacement of the armature 5.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electromagnetic solenoid.

[0002]

2. Description of the Related Art A limit switch and a reed switch are used to detect the displacement of the position of a mover of an electromagnetic solenoid. The former one detects the position of the mover by mechanically operating the limit switch to open or close when the mover is displaced to a predetermined position. In the latter, as disclosed in, for example, Japanese Patent Laid-Open No. 3-218608, a reed switch or the like detects changes in the leakage magnetic flux of the electromagnetic coil in an air gap provided in the outer casing near the electromagnetic coil. (See FIG. 4) In FIG. 4, an electromagnetic solenoid 20 includes an electromagnetic coil 21 formed by winding annealed copper wire around a bobbin 22, a yoke 23 and a fixed iron core 24 that are magnetized by an exciting current flowing through the electromagnetic coil 21, and a magnetized control. The movable element 25 and the like are arranged so as to be movable coaxially by receiving a magnetic attractive force from the fixed iron core 24. The yoke 23 also serves as an outer casing, and an air gap that exerts a magnetic action on the reed switch 30 is provided at approximately the center. Further, 26 is a compression spring for returning, and when the exciting current is zero, a component 27 which is a valve body portion of an automatic switching valve provided at one end of the mover 25 is returned by a spring force.

In this electromagnetic solenoid 20, when an exciting current is passed through the electromagnetic coil 21 in the state shown by the one-dot chain line, the mover 25-the air gap G-the fixed iron core 24-the yoke 23-the mover 2
Magnetic flux is generated in the path of 5. As a result, the mover 2
The magnetic attraction force from the fixed iron core 24 acts on the magnet 5 to be attracted thereto. At this time, magnetic flux is formed through the air gap 23a provided in the outer casing (same as the yoke 23), different magnetic poles are formed at the opposite ends of the air gap 23a, and the leakage flux causes the reed switch 30 to be magnetized. Then, the detection unit is closed. Also, on the other hand,
When the exciting current of the electromagnetic coil 21 is zero in the state shown by the alternate long and short dash line, no magnetic pole is formed at the opposite ends of the air gap 23a, and the detecting portion of the reed switch 30 repels each other to continue the open state. .

[0004]

In the electromagnetic solenoid using the limit switch and the reed switch described above, the displacement of the mover can be accurately grasped, but the mechanical life characteristics and the stable detection performance are improved. There was a problem that could not be obtained. Especially, in the latter case, the detection is due to the magnetic action due to the leakage magnetic flux in the outer casing part, and the reed switch is opened or closed not only when the mover is displaced but also in the magnetic influence near the electromagnetic solenoid. There is a case where it is in a closed state, and in such a case, the displacement of the mover cannot be reliably grasped.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electromagnetic solenoid capable of grasping the position of a mover without using a limit switch or a reed switch.

[0006]

In order to achieve the above object, an electromagnetic solenoid according to claim 1 is provided with an electromagnetic coil,
A yoke and a fixed iron core whose magnetization is controlled by the exciting current flowing in the electromagnetic coil, and a mover which is arranged so as to face the fixed iron core whose magnetization is controlled and to move coaxially by receiving a magnetic attractive force from the fixed iron core. And an electromagnetic solenoid having a spring that opposes a magnetic attractive force between the fixed iron core and the mover, the detecting means for detecting a change in the main magnetic flux that changes according to the displacement of the mover. . As a result, a detection signal corresponding to the position of the mover can be obtained.

The electromagnetic solenoid according to claim 2 is
The detecting means according to claim 1 is provided at the opposite ends of the fixed core facing the mover. This allows
A detection signal having a larger change depending on the position of the mover can be obtained.

In the electromagnetic solenoid according to the third aspect, the detecting means according to the second aspect is configured to use a magnetic-electric conversion element. As a result, continuous detection signals corresponding to the position of the mover can be obtained.

In the electromagnetic solenoid according to the fourth aspect, the detecting means according to the second aspect is a search coil. As a result, a detection signal at the transitional stage of movement of the mover can be obtained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. The electromagnetic solenoid 1 includes an electromagnetic coil 2, a yoke 3, a fixed iron core 4, and a shaft 6.
And a bearing 9 and 10 for supporting the shaft.
And a detecting means 7 for detecting a change in magnetic flux, and a spring 8
Is a main component.

The electromagnetic coil 2 includes a cylindrical winding drum portion 2a,
A bobbin 2c, which is formed of synthetic resin and has flanges 2b continuously provided at both ends thereof, is formed by winding an annealed copper wire whose surface is covered with an insulating layer on the outer periphery of the winding body 2a. It C is a lead wire which is a terminal of the electromagnetic coil 2, and is connected to an external operation circuit unit not shown. Bobbin 2c
It also has a positioning function of coaxially arranging a yoke 3 and a fixed iron core 4, which will be described later, inside the winding barrel portion 2a with a constant distance therebetween.

The yoke 3 is a bobbin 2 made of a magnetic metal material.
a cylindrical portion 3a having an outer diameter substantially equal to the inner diameter of the winding drum portion 2a of c,
A collar portion 3b having an outer diameter substantially equal to the outer diameter of the collar portion 2b of the bobbin 2c.
And is integrally formed by cutting or the like. The cylindrical portion 3a has a length that is substantially half the length of the winding drum portion 2a of the bobbin 2c, and a movable element 5 described later is coaxially loosely fitted therein. The yoke 3 is arranged such that the cylindrical portion 3a is inserted from one end side of the winding barrel portion 2a of the bobbin 2c and the collar portion 3b positions it.

The fixed iron core 4 is made of a magnetic metal material and has a cylindrical portion 4a having an outer diameter substantially equal to the inner diameter of the winding barrel portion 2a of the bobbin 2c.
And a collar 4b having an outer diameter substantially equal to the outer diameter of the collar 2b of the bobbin 2c are integrally formed by cutting or the like. The cylindrical portion 4a has a concave portion 4c facing an end portion of a mover 5 described later, and a cylindrical protrusion portion 4d having a shaft hole through which a shaft 6 and a spring 7 described later are inserted. An embedding portion 4e for embedding the detecting means 7 described later is provided at the upper end of the recess 4c, and a wiring portion 4f for connecting the signal line S of the detecting means 7 in a continuous manner with the embedding portion 4e and a cylindrical portion 4a.
Are provided on the same circumference. In addition, the collar portion 4b is provided with a wiring hole 4h through which the lead wire C of the electromagnetic coil 2 penetrates and a wiring hole 4g continuous with the wiring portion 4f of the signal line S. In this fixed iron core 4, the cylindrical portion 4a is wound around the bobbin 2c.
The yoke 3 is inserted from the other end side, is positioned by the collar portion 4b, and is opposed to the cylindrical portion 3a of the yoke 3 with a certain distance.

The mover 5 is formed of a magnetic metal material and has a columnar portion 5a having a hole for flesh relief formed at its center and a facing portion 5b facing the concave portion 4c of the fixed iron core 4. More specifically, the cylindrical portion 5a has an outer diameter smaller than the inner diameter of the cylindrical portion 3a of the yoke 3, and has a hole 5c at the center for fixing a shaft 6 described later. The facing portion 5b is the columnar portion 5
It has a substantially truncated cone shape connected to a, and has a meat relief hole corresponding to the protrusion 4d of the fixed iron core 4 and a spring 8 described later in the center.
Has a hole for inserting and locking. The mover 5 penetrates the shaft 6 through the hole 5c and is fixed at a predetermined position. Both ends of the shaft 6 are reciprocally supported by a first bearing 9 and a second bearing 10, which will be described later, and a yoke is provided. 3 is coaxially arranged inside the cylindrical portion 3a.

The shaft 6 is made of a non-magnetic metal material such as brass.
The mover 5 has an outer diameter substantially equal to the hole 5c of the mover 5.
It is formed with a sufficiently longer length. The shaft 6 is fixed to the mover 5 so that the mover 5 is located at a predetermined position of the shaft 6. Although not shown in the figure, the other end of the shaft 6 projecting downward from the electromagnetic solenoid 1 is connected and fixed to, for example, a component of the valve body portion of the automatic switching valve to form an arrow 6a.
The valve is opened and closed by being driven in the linear direction indicated by.

The detecting means 7 is formed of a magnetic-electric conversion element such as a magnetic diode element, detects the change of the main magnetic flux which changes according to the displacement of the mover, and obtains a continuous detection signal. is there. The detecting means 7 is embedded in the embedded portion 4e of the fixed iron core 4, and the signal line S thereof has a wiring hole 10b of the first bearing 10 described later via the wiring portion 4f.
Through, and is wired to a signal processing circuit including a comparison circuit and the like not shown in the drawing. This magnetic diode element
A voltage corresponding to the change in the magnitude of the magnetic flux, that is, the magnetic flux density is output, and this voltage is processed by the signal processing circuit to detect (recognize) the position of the mover. Since the magnetic diode element can obtain a detection signal in units of V, changes in the main magnetic flux can be detected with high sensitivity.

The spring 8 is a coil spring made of stainless steel or the like, one end of which is brought into contact with the movable element 5 and the other end of which is brought into contact with a first bearing 9 which will be described later, and is loosely fitted to the shaft 6, and the fixed iron core described above. 4 is loosely inserted into the shaft hole formed in the cylindrical portion 4d.

The first bearing 9 is made of synthetic resin and has a disk shape having an outer diameter dimension substantially the same as that of the collar portion 4b of the fixed iron core 4. The shaft 6 is reciprocally supported at its center portion. The shaft hole and the wiring hole 4g of the above-mentioned fixed iron core on the disk plane,
It is formed with wiring holes 9a and 9b facing 4h.

The second bearing 10 is made of synthetic resin and is slightly larger than the collar portion 10a having the outer diameter dimension substantially the same as the collar portion 3b of the yoke 3 and the inner diameter of the cylindrical portion 3a of the yoke 3. It has an intermediate portion 10b having an outer diameter dimension, and a cylindrical protrusion 10c corresponding to the meat relief hole of the mover 5, and has a shaft 6 at the center.
It is formed with a shaft hole that supports reciprocally. The second bearing 10 is positioned inside the cylindrical portion 3a of the yoke 3 by the flange portion 3b, and the intermediate portion 10b is press-fitted and fixed,
At the step surface 10d formed by the intermediate portion 10b and the protruding portion 10c,
The mover 5 pressed by the spring 8 is positioned.

The casing 11 is made of a magnetic metal material.
A hollow cylindrical portion 11a having an inner diameter slightly larger than the outer diameters of the collar portion 3b of the yoke 3 and the collar portion 4b of the fixed iron core 4, and a first cylindrical member on one end side.
The bearing 9 is formed to have an annular portion 11b on which the peripheral portion of the bearing 9 is placed. The length of the hollow cylindrical portion 11a is slightly larger than the size in which the first bearing 9, the fixed iron core 4, the electromagnetic coil 2, the yoke 3 and the second bearing 10 are laminated, and the entire tip is internally fixed. It becomes the fixing portion 11c for fixing.
Further, in the casing 11, a magnetic path is formed together with the yoke 3, the mover 5, and the fixed iron core 4 when an exciting current flows through the electromagnetic coil 2.

The electromagnetic solenoid 1 is composed of the above-mentioned members, and is assembled by first inserting the first bearing 9, the fixed iron core 4, the electromagnetic coil 2 and the yoke 3 in this order into the casing 11, and then the spring 8. After inserting the mover 5 in which the shaft 6 is fixed at a predetermined position and then press-fitting and fixing the second bearing 10, the edge portion of the casing 11 protruding from the flange portion 10a of the second bearing 10 is fixed to a predetermined position. The pressing force deforms by pressing so as to press the outside of the end of the flange 10a.

Electromagnetic solenoid 1 constructed as described above
When the exciting current of the electromagnetic coil 2 is zero, the mover 5 is moved by the spring force of the spring 8 loosely fitted to the shaft 6,
First position shown in FIG. 1 (position farthest from the fixed iron core 4)
It is in. A magnetizing current of a predetermined range flows through the electromagnetic coil 2, so that the yoke 3, the mover 5, and the gap L
A magnetic path is formed by the fixed iron core 4 and the casing 11 which are arranged so that a magnetic attractive force toward the fixed iron core 4 side acts on the mover 5 in the gap L. The mover 5 and the shaft 6 immediately start moving in the direction indicated by the arrow 6a due to this magnetic attraction, and further overcome the spring force of the spring 8 to reach the second position (the fixed iron core 4 is most Reach a close position). At this time, the magnetic flux in the gap L changes as the mover 5 moves from the first position to the second position, but the output voltage of the detection means 7 also changes at the same time. This output voltage is compared by the comparison circuit forming the signal processing circuit described above, and when it exceeds a predetermined set value, the arrival of the mover 5 at the second position is detected (recognized).

The detecting means 7 is provided in the embedded portion 4e at the upper end of the recess 4c of the fixed iron core 4. The upper end of the detecting means 7 is located on the opposing surface forming the gap L with the mover 5, and the mover 5
The magnetic flux is most concentrated in the initial stage when the magnetic flux moves toward the fixed core 4. Therefore, the detection means 7 embedded in the embedded portion 4e can detect the largest change in magnetic flux as a change in voltage when the mover 5 is displaced from the first position to the second position. Further, in the first embodiment, the detecting means 7 is provided on the fixed iron core 4 which is a fixing member, so that the detecting means 7 is provided.
The wiring of the signal line S for extracting the signal from the wiring is easy, and since the wiring does not hinder the operation of the mover, the operation of the mover becomes stable.

The magnetic-electrical conversion element of the detection means 7 may be a magnetic resistance element or a Hall element instead of a magnetic diode element, and a change in magnetic flux may be detected as a change in output voltage. However, in the Hall element, the output signal line of the magnetic diode element or the like is composed of two terminals, whereas the output signal line is composed of four terminals, which is somewhat disadvantageous in terms of wiring space.

Next, a second embodiment of the present invention will be described with reference to FIG. This is different from the first embodiment only in the configuration of the detecting means. This detection means 7
Is formed by a search coil, and this search coil is
It is formed to have a detecting portion 7a formed by winding an annealed copper wire whose surface is covered with an insulating layer a plurality of times, and a lead wire S. This search coil is embedded in the embedded portion 4e of the fixed iron core 4,
The detection surface of the detection portion 7a formed by winding is provided so as to face the direction perpendicular to the main magnetic flux, and the signal line S is connected to the fixed iron core 4 described above.
Wiring is performed by penetrating the wiring hole 10b of the first bearing 10 through the wiring portion 4f.

This one detects the change of the magnetic flux in the transient stage of the excitation accompanying the displacement of the mover 5 from the first position to the second position or the displacement from the second position to the first position. . More specifically, in the displacement of the position of the mover 5,
The generation or disappearance of the magnetic flux penetrating the search coil provided in the embedded portion 4e of the facing surface forming the gap L can be detected as a signal at the transitional stage of the displacement of the mover 5. This detection signal has different polarities depending on whether the exciting current of the electromagnetic coil 2 is turned on or off, and is a signal obtained by directly detecting the exciting current used to move the position of the mover 5. The above process can be detected earlier, which is particularly effective in high-speed drive control of the mover.

[0027]

According to the electromagnetic solenoid of the first aspect, since the detection signal corresponding to the position of the mover is obtained, the position of the mover can be detected without using a limit switch or a reed switch externally.

Furthermore, in addition to the effect of claim 1, the electromagnetic solenoid according to claim 2 can obtain a detection signal of a larger change according to the position of the mover, so that the position of the mover can be accurately detected. .

The electromagnetic solenoid according to claim 3 is
In addition to the effect of the second aspect, since a continuous detection signal corresponding to the position of the mover is obtained, it becomes easy to detect (understand) the displacement of the position of the mover in the signal processing circuit.

The electromagnetic solenoid according to claim 4 is
In addition to the effect of the second aspect, since the detection signal of the transitional stage of the movement of the mover is obtained, the mover can be driven and controlled at high speed.

[Brief description of drawings]

FIG. 1 is a front cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a partial perspective view of the detecting means.

FIG. 3 is a partial perspective view of a detection means, which is a main part of a second embodiment of the present invention.

FIG. 4 is a front sectional view showing a conventional example.

[Explanation of symbols]

 2 Electromagnetic coil 3 Yoke 4 Fixed iron core 5 Mover 6 Shaft 7 Detecting means 8 Spring 9 First bearing 10 Second bearing 11 Casing

Claims (4)

[Claims] 1. An electromagnetic coil, a yoke and a fixed iron core whose magnetization is controlled by an exciting current flowing through the electromagnetic coil, and a fixed iron core which is magnetized and controlled, and is moved coaxially by receiving a magnetic attractive force from the fixed iron core. A mover arranged so that
An electromagnetic solenoid having a spring that opposes a magnetic attractive force between the fixed iron core and the mover, wherein a detecting means for detecting a change in the main magnetic flux that changes according to the displacement of the mover is provided. Electromagnetic solenoid. 2. The detecting means is provided at opposite ends of a fixed core facing the mover.
Electromagnetic solenoid as described. 3. The electromagnetic solenoid according to claim 2, wherein the detection means is formed by a magnetic-electric conversion element. 4. The electromagnetic solenoid according to claim 2, wherein the detection means is formed by a search coil.