JPS6138166Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a self-holding solenoid capable of holding a plunger operating position without supplying a holding current.

FIG. 1 shows the structure of a conventionally used self-holding solenoid of this kind, in which one end of a cylindrical magnetic yoke 11 is closed by an integral closing plate 11a. A cylindrical fixed receiver 12 is formed at the center of the inner surface of the closing plate 11a to protrude in the axial direction. A fixed receiver 12 is attached to the free end surface of this fixed receiver 12.
A cylindrical permanent magnet 13 having the same diameter is attached.

A cylindrical body 14 made of, for example, steel and having an inner diameter slightly larger than the outer diameter of the fixed receiver 12 is fitted onto the fixed receiver 12. This cylindrical body 14 is the magnetic yoke 1
It has a sufficient length to be extended close to the open surface of No. 1. A cylindrical movable core 15 having approximately the same diameter as the fixed receiver 12 is inserted into the cylindrical body 14 so as to be slidable along the axis of the magnetic yoke 11 .

A coil 16 is wound on the cylindrical body 14.
A cover 17 made of an annular magnetic material and having an outer diameter equal to the inner diameter of the magnetic yoke 11 and an inner diameter equal to the outer diameter of the cylindrical body 14 is inserted and fixed into the open end of the magnetic yoke 11 . Although the movable iron core 15 is not shown in the figure,
For example, the movable iron core 15 and the permanent magnet 13 have a configuration in which the movable iron core 15 and the permanent magnet 13 are deflected in a direction to be pulled out from the magnetic yoke by a return spring and are received by a stopper.
A gap g is formed between them.

In a conventional self-holding solenoid having such a structure, an operating current in a predetermined direction is supplied to the coil 16 by a means (not shown) during operation. Due to this operating current, a magnetic field H ₁ approximately parallel to the axis of the cylindrical body 14 is formed within the cylindrical body 14 . For this reason, a closed path consisting of the magnetic yoke 11, fixed receiver 12, permanent magnet 13, and movable core 15 is formed, and the magnetic energy in this closed path exerts force on the movable part, causing the movable core 15 to move and become a permanent magnet. 13.

Even if the operating current to the coil 16 is cut off in this abutting state, the movable iron core 15 is maintained in its position by the magnetic attraction force of the permanent magnet 13.
Next, in order to separate the movable iron core 15 from the permanent magnet 13, a return current smaller than the operating current and in the opposite direction is supplied to the coil 16. Due to this return current, a magnetic field H ₁ substantially parallel to the axis and a magnetic field H ₂ opposite to the magnetic field of the permanent magnet 13 are formed in the cylindrical body 14 . This magnetic field _H2 cancels the magnetic field of the permanent magnet 13, and the attractive force of the permanent magnet 13 to the movable core 15 decreases, or becomes zero, and a return spring (not shown) causes the permanent magnet 13 to move the movable core 1.
5 will leave and return to its original position.

However, in this conventional self-holding solenoid, since the movable iron core 15 directly contacts the permanent magnet 13, the permanent magnet 13 is easily damaged. Furthermore, when the gap g becomes large to a certain extent, the attraction force decreases rapidly, and sufficient attraction force cannot be generated, and the magnetomotive force of the coil 16 fluctuates due to voltage fluctuations and temperature changes, and the attraction return characteristic becomes large. Subject to change and impractical.

In order to compensate for this difficulty, measures have been considered such as using oxide magnets with a large magnetic force and devising a magnetic circuit, but this increases the size of the permanent magnet 13 and naturally increases the manufacturing cost. In addition, the coercive force of oxide magnets, etc., which are generally used in this type of solenoid is large, and it is difficult to demagnetize them. Therefore, when the return current to the coil 16 is cut off, the permanent magnet 1
The magnetized state No. 3 remains as it is. Therefore, the movable iron core 15, which is in the restored state, is damaged by the magnet 1 due to mechanical vibration, etc.
If it moves in three directions, there is a risk that the movable iron core 15 will be easily attracted by the attractive force of the permanent magnet 13.

For this reason, in the conventional type, it is necessary to keep the spring force of the return spring relatively strong. Naturally, during operation, the movable iron core 15 must be moved against the force of the return spring, which increases the operating current and causes the coil 16 to move.
It is necessary to increase the number of windings, and this increases the size of the holding means at the return position, which is undesirable.

This invention solves the above-mentioned problems of the conventional solenoid and provides a self-retaining solenoid that is compact and has a simple structure, yet can operate reliably and reduce manufacturing costs.

Hereinafter, the self-holding solenoid of this invention will be explained in detail based on an embodiment thereof using the drawings.

FIG. 2 shows the structure of an embodiment of the self-holding solenoid of this invention, and parts corresponding to those in FIG. 1 are given the same reference numerals. Although not specifically described in FIG. 1, attachment of the fixed receiver 12 to the closing plate 11a is carried out, for example, as follows. A small hole 23 is provided in the center of the closing plate 11a, while the closing plate 1 of the fixed receiver 12
It has a structure in which the support tube 20 is integrally projected from the center position on the side 1a. The support tube 20 is inserted into the small hole 23, and the protruding portion of the support tube 20 is pushed out to the surroundings, so that the fixed receiver 12 is reliably tightened to the closing plate 11a. Note that a small hole 23 is formed to extend along the axis of the fixed receiver 12 so that air can easily enter and exit the gap g when the movable core 15 is moved.

Further, in this embodiment, the movable iron core 15 is connected to the magnetic yoke 1.
The permanent magnet 13 is interposed between the two movable iron core parts on both sides. The permanent magnet 13 is an alnico magnet having a characteristic that it can be magnetized by a predetermined magnetic field and demagnetized by a magnetic field in the opposite direction.

A convex surface 22 having a V-shaped cross section including its axis is provided on the surface of the movable core 15 facing the fixed receiver 12. Further, a V-shaped concave surface 21 into which the above-mentioned convex surface 22 can be fitted is provided on the end surface of the fixed receiver 12 that faces this V-shaped convex surface 22. With this structure, the movable core 1
5 and the fixed receiver 12 becomes larger, and it becomes possible to increase the suction force of the movable iron core 15.

Further, in the embodiment, an operating coil 18 is provided on the cylindrical body 14.
is wound thereon, and a return coil 19 is further wound thereon. The operation coil 18 and the return coil 19 are connected to a power source, for example, as shown in FIG. 3. That is, one ends of both coils 18 and 19 are connected to each other and connected to one end of the power source E, and each other end is connected to the other end of the power source E through the switches SW ₁ and SW ₂ , respectively.

_Furthermore , _the coil 18,
19 winding directions are selected. In the example shown in FIG. 3, the wires are wound in the same direction and the current flows in opposite directions.
When the solenoid is in operation, when the switch SW ₁ shown in FIG. 3 is turned on, an operating current flows through the switch SW ₁ to the operating coil 18. This operating current creates a magnetic field approximately parallel to the axis within the cylindrical body 14.
H ₁ is formed. This magnetic field H ₁ is the magnetic yoke 1
1. A closed magnetic path is formed through the fixed receiver 12 and the movable core 15, and the magnetic energy of this closed magnetic path causes the movable core 15 to move toward the fixed receiver 12 and come into contact with it.
Also, the permanent magnet 13 is magnetized by this magnetic field H ₁ , and even if the operating current is cut off in this state, the permanent magnet 13 retains residual magnetism B ₁ according to the B-H characteristic curve of the permanent magnet 13 shown in FIG. It will remain. Therefore, due to the magnetic force of the permanent magnet 13, the movable iron core 15 is moved to the fixed receiver 12.
It is attracted to the side and held by the fixed receiver 12.

Next, to perform the return operation, press the switch shown in Figure 3.
Insert SW ₂ . A return current flows through the switch SW ₂ to the return coil 19, and this current creates a magnetic field H ₂ in the cylindrical body 14 that is substantially parallel to the axis and in the opposite direction to H ₁ . The residual magnetism of the permanent magnet 13 is demagnetized by this magnetic field _H2 . Therefore, even with a very weak return spring, the movable core 15 can be detached from the fixed receiver 12 and returned to its original position. In this case, if a solenoid is used with the protruding direction of the movable core 15 facing downward, the movable core 15 will return by its own weight, so a return spring will not be necessary.

At this time, as shown in FIG. 4, the value of the magnetic field H ₂ may vary somewhat due to the influence of temperature changes, voltage fluctuations, etc. For example, if the magnetic field is H ₃ (|H ₃ |<|H ₂
In the case of ｜), a residual magnetic flux density B ₂ will remain, but the attraction force due to this is weak, so if a weak return force is applied to overcome this, it will easily return to its original position. . Also, the magnetic field is H ₄ (｜H ₂ ｜
<|H ₄ |), the residual magnetic flux density B ₃ will remain, but the magnetization polarity due to the magnetic field H ₄ will be in the opposite direction and the residual magnetic flux density will pass through the zero point at the reversal stage, so this It returns to its original position at the passing point.

In reality, there is magnetic resistance due to the components of the magnetic circuit of the solenoid, so B″ ₁ , B′ ₂ ,
As shown as B′ ₃ , B ₁ , B ₂ , and B ₃ each have small values. The resistance of the magnetic circuit of the solenoid is R
Then, if the permeance coefficient P is 1/R, the magnetic field due to the magnetomotive force of the coil is H, and the magnetic flux of the iron core is B, then there is a relationship of P=1/R=B/H.

Since the magnetomotive force required at the time of return may be about 1/4 of the magnetomotive force required at the time of operation, the number of turns of the return coil 19 may be smaller than that of the operating coil 18, for example. In the self-holding solenoid of this invention, an alnico magnet is used as the permanent magnet 13, which is magnetized at room temperature and is easily demagnetized. The coercive force of alnico is about 1/3 to 1/4 of the coercive force of the permanent magnets used in the conventional magnets shown in Figure 1, such as oxide magnets, and it can be demagnetized even with a small return current. .

Demagnetizing conventional oxidized magnets is extremely difficult and requires heating at temperatures above the Curie temperature (450°C). However, the permanent magnet used in this invention can be easily magnetized and demagnetized repeatedly at room temperature by supplying operating current and return current to the operating coil and return coil. Also the fourth
As shown in the dotted curves H′ ₂ and B′ ₁ in the figure, it is generally desired that permanent magnets have a large coercive force H′ ₂ , but in this design, the coercive force H ₂ is small and the residual magnetic flux density B ₁ It is also clear that it is desirable that the resistance of the magnetic circuit of the solenoid be as small as possible.

In this way, in the embodiment shown in FIG. 2 of this invention, the permanent magnet 1 is supplied with the operating current and the return current.
3 can easily repeat magnetization and demagnetization, and the movable iron core 15 has a fixed receiver 12, a V-shaped convex surface 22 and a V-shaped concave surface 21 with a large opposing area.
A strong attractive force is obtained and the permanent magnet 13 is self-retained by the magnetomotive force, and since the permanent magnet 13 is made of alnico, the residual magnetic flux Br
is large, and a large holding force can be obtained as a whole.
In addition, when the permanent magnet 13 inserted into the movable core 15 in a plane perpendicular to the axis is inserted into the movable core 15 in a plane perpendicular to the axis, as shown in FIG. It is most effective to insert it into the movable core 15 at the center position of the length h in the direction. Since the permanent magnet 13 is made of alnico, it has high mechanical strength, and there is no risk of damage due to impact when the movable iron core 15 is attracted.

The magnetic yoke may be of any shape as long as it constitutes a closed magnetic path including a movable iron core and a fixed receiver, similar to conventional solenoids of this type, and may have other shapes.

As described above in detail, the self-holding solenoid of this invention has a structure in which the alnico permanent magnet 13 is inserted into the movable iron core 15 in a plane perpendicular to the axis. In addition, since this permanent magnet is made of alnico, it has a large residual magnetism Br and a small coercive force Hc.Furthermore, since the movable iron core 15 and the fixed receiver 12 have V-shaped opposing surfaces, they have an extremely strong attraction during operation. Power is obtained and self-retention is performed with a large force, and when released, it returns smoothly with a small return current.

Therefore, according to this invention, it is possible to provide a self-holding solenoid which is compact and strong, has a simple holding means at the return position, and can realize reliable operation without malfunction.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of a conventionally used self-holding solenoid, Fig. 2 is a diagram showing the configuration of an embodiment of the self-holding solenoid of this invention, and Fig. 3 is a diagram showing the operation of the embodiment of Fig. 2. A diagram showing the electrical connection of the coil and the return coil, Figure 4 is a diagram showing the characteristics of the permanent magnet used in the self-holding solenoid of this invention, and Figure 5 is a diagram showing the characteristics of the permanent magnet used in the self-holding solenoid of this invention. This is a corresponding diagram. 11: Magnetic yoke, 12: Fixed receiver, 13: Permanent magnet, 15: Movable iron core, 18: Operating coil, 1
9: Return coil.

Claims (1)

[Scope of Claim for Utility Model Registration] A movable iron core is disposed within the coil so as to be movable along the axis, the movable iron core protrudes outward from one end of the coil, and the movable iron core is sucked into the other end of the coil. A fixed receiver is provided to catch the magnetic yoke when the magnet is rotated, and one end of the magnetic yoke is connected to the fixed receiver.
The other end of the magnetic yoke is a self-holding solenoid that is extended to a position close to the side surface of the part of the movable core that protrudes from the coil. A V-shaped convex portion is integrally formed on the surface of the movable core facing the fixed receiver, and the convex portion is fitted onto the surface of the fixed receiver facing the movable core so that the entire surface faces the convex portion. A V-shaped recess is formed, and an alnico permanent magnet is inserted into the movable core so as to bisect it in the linear direction, and with the movable core protruding outward, the axis of the magnetic yoke is The permanent magnet is located approximately half the length in the direction, and the two halves of the permanent magnet are connected to each other, and the operating magnetic field generated by the operating current supplied to the operating coil is The above permanent magnet is magnetized by
The permanent magnet is almost demagnetized by the restoring magnetic field generated by the restoring current supplied to the restoring coil, and the fixed receiver has a small hole extending from the bottom of the V-shaped recess to the outside. Features a self-holding solenoid.