JPS6127140Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a self-holding solenoid.

Recently, solenoids have been widely used in various electronic devices including VTRs, but as these electronic devices have become smaller, lighter, and more energy efficient, solenoids have become smaller and more energy efficient. requested.

Conventionally, as this type of solenoid, a so-called self-holding type solenoid, which uses a permanent magnet to self-maintain its operating state, has been considered. However, since this type uses a permanent magnet, it is difficult to miniaturize it, and the magnetic flux of the permanent magnet easily leaks to the outside, which not only has an adverse effect on other parts, but also changes its characteristics significantly depending on the solenoid installation conditions. There were some drawbacks.

This idea was made in view of the above circumstances,
The purpose of the present invention is to provide a self-holding solenoid that is small in size and provides stable operation.

An embodiment of this invention will be described below with reference to the drawings.

In FIGS. 1a, b, c, and d, 1 is a cylindrical bobbin, and an excitation coil 2 is wound around this bobbin 1. Further, a pipe 3 made of a non-magnetic material is inserted into the hollow portion of the bobbin 1.

In this case, pipe 3 is omitted and pipe 3 is placed on bobbin 1.
It may also be made to have the function of

A fixed iron core 4 is fitted into one open end of the bobbin 1, and a movable iron core 5 is inserted through the other open end so that the tip of the movable iron core 5 can approach and separate from the fixed iron core 4.

A frame 6 is provided to surround the excitation coil 2. This frame 6 has a U-shaped cross section, and the fixed iron core 4 is provided at the bottom.

A magnetic body 7 is provided inside the frame 6 on the open side in contact with the other open end of the bobbin 1. The magnetic body 7 has a plate shape having a hollow part coaxially with the hollow part of the bobbin 1, and the pipe 3 is inserted through this hollow part. In this case, a cap G ₂ is provided between the outer peripheral surface of the magnetic body 7 and the inner peripheral surface of the frame 6.
We are trying to form a

Also, the front frame 8 is attached to the open end of the frame 6.
has been established. This front frame 8 has a plate shape having a hollow part coaxially with the hollow part of the bobbin 1, and a gap _G1 is formed between the circumferential surface of the hollow part and the movable iron core 5. .

Then, a permanent magnet 9 is inserted between the magnetic body 7 and the front frame 8 with the polarity shown. For example, a rare earth permanent magnet is used as the permanent magnet 9. Moreover, this permanent magnet 9 forms an annular body, and there is a gap between its inner peripheral surface and the movable iron core 5.
It forms G ₁ .

In this case _{, the gaps G 1 and} G ₂ are the relationship between g and the gap between the fixed core 4 and the movable core 5 as shown in Figure 1a.
When G ₃ is set, the relationship is set as G ₃ > G ₁ and G ₃ > G ₂ .

Next, its effect will be described.

First, as shown in FIG. 1a, when the fixed core 4 and the movable core 5 are separated, that is, before the excitation coil 2 is energized, the magnetic fluxes of the permanent magnet 9 are φ ₁ and φ
₂ and _φ3 and are transmitted. However, in this case, the gap between the fixed core 4 and the movable core 5
Since G ₃ is large, most of the magnetic flux is transmitted as φ ₂ and φ ₃ . Therefore, almost no suction force acts between the fixed iron core 4 and the movable iron core 5. This allows the biasing force of the return spring (not shown) of the movable core 5 to be weakened to the minimum necessary limit. Further, since the movable core 5 can be attracted to the permanent magnet 9 side by the magnetic flux φ ₂ , the returned state of the movable core 5 can be stably maintained even if vibrations are applied from the outside.

When the excitation coil 2 is energized from this state, the first
As shown in FIG. b, the magnetic flux φ ₁₁ is transmitted, and the movable core 5 is attracted to the fixed core 4 and moved to the left in the figure. In this case, when the magnetomotive force of the excitation coil 2 is increased in order to increase the attractive force, magnetic saturation occurs in the permanent magnet 9, but in this state, the magnetic flux _φ4 is transmitted, so that the attractive force can be reliably increased.

After the movable iron core 5 is attracted to the fixed iron core 4, this state is maintained by the magnetic flux _φ1 of the permanent magnet 9, as shown in FIG. 1c, even if the excitation coil 2 is released.

After that, in order to return the movable iron core 5, see Fig. 1d.
As shown in , when the excitation coil 2 generates a magnetic flux φ ₁₂ in the opposite direction to the above magnetic flux φ ₁₁ , the magnetic flux φ of the permanent magnet 9
₁ is canceled, the movable core 5 and the fixed core 4 are released from adsorption, and the movable core 5 is returned by a return spring (not shown).

Therefore, with such a configuration, the operating state of the movable iron core can be reliably maintained by the permanent magnet, thereby making it possible to save power.
In this case, since the permanent magnets are arranged inside the frame, the magnetic flux of the permanent magnets will not leak to the outside.
This not only reliably prevents adverse effects on others, but also prevents changes in characteristics due to installation conditions, thereby providing stable operation. Further, since the permanent magnet is an annular body and can generate magnetic flux from the entire periphery, a large magnetic flux can be obtained, and the operation holding force can be increased accordingly. Furthermore, this means that if the operating holding force is constant, the permanent magnet can be made smaller, and the solenoid can be made smaller accordingly. Furthermore,
Since the biasing force of the return spring connected to the movable iron core can be weakened, the effective attractive force acting on the movable iron core when the excitation coil is energized can be increased accordingly.

Note that this invention is not limited to the above-mentioned embodiments, but can be implemented with appropriate modifications without changing the gist. For example, as shown in FIG. 2, a small diameter portion 51 may be formed in the movable iron core 5, and a gap _G1 may be formed between the inner peripheral surfaces of the front frame 8 and the permanent magnet 9, respectively, and the movable iron core 5. good. Even in this case, the same effect as described above can be obtained.

As described above, according to this invention, it is possible to provide a self-holding solenoid that is compact and provides stable operation.

[Brief explanation of the drawing]

Figures 1a, b, c, and d show one embodiment of this invention, in which a is a schematic diagram showing a pre-operation state, b is an operating state, c is an operation holding state, and d is a return state, respectively; FIG. 2 is a schematic diagram showing another embodiment of the present invention. 1...Bobbin, 2...Exciting coil, 3...Pipe, 4...Fixed core, 5...Movable core, 6...Frame, 7...Magnetic material, 8...Front frame, 9...Permanent magnet , 51...small diameter section.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A cylindrical bobbin wound with an excitation coil, a fixed iron core fitted into one open end of the bobbin, and a fixed iron core inserted through the other open end of the bobbin and connected to the fixed iron core. a movable iron core that can be separated; a frame with a U-shaped cross section that surrounds the excitation coil; and a magnetic body that is provided inside the frame on the open side and has a hollow part coaxially with the hollow part of the bobbin. a front frame provided at the open end of the frame and having a hollow portion coaxially with the hollow portion of the bobbin; and a ring-shaped front frame having one magnetic pole surface on the magnetic body side and the other magnetic pole surface on the front frame side. a permanent magnet, G 1 is a gap between the hollow circumferential surface of the front frame and the movable iron core, and G ₁ is a gap between the outer circumferential surface of the magnetic body and the inner circumferential surface of the frame.
G ₂ , G ₃ is the gap between the movable core and the fixed core when they are separated, and g is the gap between the circumferential surface of the hollow part of the magnetic material and the movable core.
A solenoid characterized in that respective gaps are set in the relationships of ≪G ₁ , g≪G ₂ , G ₃ >G ₁ , and G ₃ >G ₂ . (2) The solenoid according to claim 1, wherein the movable iron core has a small diameter portion that corresponds to the front.