JPS6025861Y2 - solenoid - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a self-holding solenoid with improved operation holding force.

Recently, solenoids have been widely used in various electronic devices such as VTRs, but as these devices are becoming smaller, lighter, and more energy efficient, solenoid models that are smaller and more energy efficient are being considered. .

Conventionally, as this type of solenoid, a solenoid that uses a permanent magnet to self-maintain its operating state has been considered.

However, in this device, when a smaller permanent magnet is used as part of the miniaturization effort, the operating holding force decreases accordingly, and there is a risk that the load may be reset erroneously.

For this reason, it is difficult to downsize the permanent magnet in order to ensure the desired holding force, and this poses an obstacle to downsizing the solenoid.

This idea was made in view of the above circumstances, and it is small and
Moreover, it is an object of the present invention to provide a self-holding type solenoid that can obtain sufficient operation holding force.

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

In FIGS. 1 to 4, reference numeral 1 denotes a cylindrical bobbin around which an excitation coil 2 is wound, and this bobbin 1 has a protruding wall 1a along the periphery of one opening end.

Magnetic bodies 3 and 4 are provided in this projecting wall 1a, and one magnetic pole face (
S pole) side is provided.

The magnetic bodies 3 and 4 each form a hollow portion that communicates with one opening of the bobbin 1.

Here, if the diameter of the hollow part of the magnetic body 3 is a11 and the diameter of the hollow part of the specimen 4 is b, then b is set to a, and b is slightly larger than the diameter of the movable iron core 10, which will be described later.

Further, the permanent magnet 5 has an annular shape.

A cushioning material 6 such as rubber is inserted between the permanent magnet 5 and the hollow part of the magnetic body 4, and a heat-resistant and abrasion-resistant film 7 is interposed between the magnetic bodies 4 and 3. The cushioning material 6 is designed to absorb the movement of a movable core 10, which will be described later.

A frame 8 is provided to surround the excitation coil 2.

This frame 8 has a U-shaped cross section, and has the other magnetic pole surface (N pole) of the permanent magnet 5 and the buffer material 6 in contact with the bottom thereof.

Further, a front frame 9 having a hole communicating with the other opening of the bobbin 1 is provided at the open end of the frame 8.

A movable iron core 10 is movably inserted through the hole of the front frame 9 into the hollow portion of the pobbin 1.

This movable core 10 has a groove 101 with a V-shaped cross section, for example, in the center of the side that comes into contact with the buffer material 6, that is, the center of the tip, and has a cross-sectional area such that the magnetic flux is concentrated on the peripheral edge of the tip. is made smaller.

Next, its effect will be explained.

First, as shown in FIG. 1, when the movable iron core 10 is separated from the buffer material 6, that is, before the excitation coil 2 is energized, the magnetic flux of the permanent magnet 5 is φ1. The light is transmitted separately into φ2 and φ3.

However, in this case, the gap between the movable iron core 10 and the magnetic bodies 3 and 4 is sufficiently large, so that most of the magnetic flux flows through φ2. φ
It is transmitted as 3.

Therefore, almost no suction force acts on the movable core 10, so there is no malfunction of the movable core 10 due to external vibrations, etc.
This also allows the biasing force of the return spring (not shown) to be weakened to the minimum necessary level.

When the exciting coil 2 is energized from this state, the magnetic flux φ11 is transmitted through the movable iron core 10 as shown in FIG.
4 and is moved to the left in the figure until it comes into contact with the cushioning material 6.

After the movable iron core 10 contacts the buffer material 6, the excitation coil 2
Even if the bias is released, this state is maintained by the magnetic flux φ□ of the permanent magnet 5, as shown in FIG.

After that, in order to return the movable iron core 10, as shown in FIG.
When ゜ is generated, while the magnetic flux φ□ of the permanent magnet 5 is canceled out, the adsorption between the movable core 10 and the magnetic body 4 is released, and the movable core 1
0 is returned by a return spring (not shown).

Therefore, according to such a configuration, the operating state of the movable iron core 10 can be reliably maintained by the permanent magnet 5, thereby making it possible to save power.

In this case, the movable iron core 10 has a V-shaped groove 101 formed in the center of the tip surface to increase the magnetic flux density at the peripheral edge of the tip surface, so that the magnetic flux of the permanent magnet 5 is effectively transmitted to the magnetic body 4. Moreover, since the tip of the movable core 10 is positioned near the edge of the magnetic body 4, maximum attractive force can be obtained between the movable core 10 and the magnetic body 4, and as a result, the holding force in the operating state can be dramatically increased. can be increased to

This means that if the operation holding force is constant, the permanent magnet can be made smaller, and the solenoid can also be made smaller accordingly.

In addition, since the movable core 10 can be moved by the buffer material 6, a noise reduction effect can be expected.

In this case, since the film 7 is provided on the side of the cushioning material 6, even if rubber or the like is used as the cushioning material 6, and even if it becomes sticky due to heat and deterioration, this state can be reliably prevented from affecting the movable iron core 10 side. , it is also possible to improve operational reliability.

Furthermore, since the movable iron core 10 does not directly collide with the permanent magnet 5, deterioration of the permanent magnet 5 caused by this can be prevented.

Furthermore, since the magnetic flux φ1° generated by the excitation coil 2 when returning the movable iron core 10 does not pass through the magnetic body 34 to the permanent magnet 5, unnecessary demagnetization of the permanent magnet 5 can be prevented.

Further, since the biasing force of the return spring connected to the movable iron core 10 can be weakened, the effective attractive force acting on the movable iron core 10 when the excitation coil 2 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, in the above description, the tip of the movable iron core 10 is received by the cushioning material 6, but the cushioning material 6 and the frame 7 may be omitted, and the tip of the movable iron core 10 may be directly received at the periphery of the hollow part of the magnetic material 4. .

In this case, the magnetic body 3 can be omitted.

In this case, although the silencing effect is somewhat inferior, it is possible to increase the operation retention force.

If a material such as a damping steel plate is used as the magnetic material 4, the silencing effect can also be solved.

As described above, if this invention is applied, it is possible to provide a self-holding type solenoid which is small in size and has sufficient operation holding force.

[Brief Description of the Drawings] Figures 1 to 4 show an embodiment of this invention. Figure 1 shows the state before operation, Figure 2 shows the operating state, Figure 3 shows the operation holding state, and The figures are schematic configuration diagrams showing respective return states. 1...Bobbin, 2...Excitation coil, 3
, 4... Magnetic material, 5... Permanent magnet, 6...
...Cushioning material, 7...Song film. 8...Frame, 9...Front frame, 10...Movable iron core, 101...Curved groove.

Claims (3)

[Scope of utility model registration request] (1) A cylindrical bobbin around which an excitation coil is wound, a magnetic body provided on one opening side of the bobbin and having a hollow portion communicating with the one opening of the bobbin, and one magnetic pole surface provided on the magnetic body. a permanent magnet; a frame that is provided to surround the excitation coil and has a hole in which the other magnetic pole surface of the permanent magnet is provided and communicates with the other opening of the bobbin; What is claimed is: 1. A solenoid comprising: a movable iron core that is movably inserted into a hollow portion of the solenoid and has a groove formed in the center of a distal end surface. (2) The solenoid according to claim 1, which is a registered utility model, characterized in that a cushioning material for catching movement of the movable core is inserted in the hollow portion of the magnetic body. (3) The solenoid according to claim 1 or 2, wherein the movable iron core has a groove in the center of the tip end face having a cross-sectional shape.