JPH0529131A - Solenoid - Google Patents

Abstract

PURPOSE:To allow sure operation by using a permanent magnet. CONSTITUTION:A magnet assembly 30 deviated by a spring 40 so as to keep a fixed space between the front edge of a solenoid coil 10 and the assembly 30 is fixed on a plunger 20, the magnet assembly 30 is formed of a magnetic cup 31 and a ring-shaped permanent magnet 32 fixed in the cup 31 and the periphery of an opening on the cup 31 is extended from the ring-shaped permanent magnet 32. Thus, magnetic force lines are concentrated on the periphery of the opening on the cup, strong attraction is allowed and sure and strong operation and holding power are guaranteed by small-quantity momentary conduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid, and more particularly to a solenoid capable of attracting and holding a permanent magnet.

[0002]

2. Description of the Related Art Generally, a solenoid excites a coil to attract a plunger, but in order to maintain this attraction state, the coil must be continuously energized, causing heat generation and burning of the coil. In addition, there is a problem that power consumption also increases.

There is also a problem that if the power supply is cut off due to a power failure or the like during operation, the holding state is restored.

[0004]

Therefore, there is a device in which a permanent magnet is arranged in series with a coil, the coil is energized for a short time to attract the plunger, and the state is held by the permanent magnet.

Since the permanent magnet holds the attracted state of the plunger, there is no need to energize during that time, and there is an advantage that power consumption can be reduced.

However, since the permanent magnet is arranged so as to surround the plunger in series with the coil, the attraction force to the plunger is weak and the operation is unstable.
There is a limit to how strong the magnetic force of a permanent magnet can be.

Therefore, an object of the present invention is to provide a solenoid which operates by instantaneous energization and which can stably hold a suction state.

[0008]

In order to solve the above-mentioned problems, a solenoid of the present invention includes a solenoid coil, a plunger having a center of the coil movable in an axial direction, and a front end of the coil. A magnet assembly attached to the plunger, and a spring that presses this magnet assembly away from the coil,
The magnet assembly includes a magnetic body provided at a front end portion of a coil facing the magnet assembly. The magnet assembly includes a ring-shaped permanent magnet and a magnetic body cup that covers the ring-shaped permanent magnet. Facing the body,
Further, it is characterized in that it slightly protrudes from the ring-shaped permanent magnet.

[0009]

Since the magnet assembly is composed of the ring-shaped permanent magnet and the magnetic cup covering the ring-shaped permanent magnet, and the periphery of the opening of the cup is slightly projected from the ring-shaped permanent magnet, the lines of magnetic force are concentrated on the periphery of the opening. ..

When the solenoid coil is energized, the plunger is attracted and the peripheral edge of the cup is attracted to the magnetic material provided on the coil to hold the plunger at that position.
At the same time, the power supply should be cut off.

Further, in order to return the plunger, it suffices to energize it in the opposite direction to the energization and push out the plunger to such an extent that the attraction of the magnet assembly is released.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the solenoid 1 comprises a solenoid coil 10, a plunger 20 and a magnet assembly 30.

The solenoid coil 10 is a frame 1
Frame 1 housed in a casing consisting of 1 and 12
In the center hole 13 of the guide 2, the guide 1 of the plunger 20 is provided.
4, 15 are fixed. A ring 16 made of a magnetic material is fixed to the front end of the frame 12.

The plunger 20 is slidably mounted along guides 14 and 15 provided in the center hole 13, and a stop ring 21 is fixed to the rear end of the plunger 20. Also, color 2 from the front end towards the center
Two are provided.

As shown in FIGS. 1 and 2, the magnet assembly 30 comprises a magnetic material cup 31 and a ring-shaped permanent magnet 32 fixed inside the magnetic material cup 31. The peripheral edge 33 of the opening of the cup 31 projects from the outer surface 34 of the ring-shaped permanent magnet 32. That is, the outer surface 34 of the permanent magnet 32
Is at a level lower than the peripheral edge 33 of the opening of the cup 31. Further, the diameter of the ring-shaped permanent magnet 32 is made slightly smaller than the inner diameter of the cup 31 so that a gap is formed between the ring-shaped permanent magnet 32 and the inner peripheral surface of the cup 31. And cup 31
Plunger 20 is inserted into the center hole 35 of the.

The collar 22 of the plunger 20 serves as a stopper for the cup 31 fitted in the plunger 20, and the coil spring 40 holds the cup 31 in the collar 22.
Are pressed against. Therefore, the magnet assembly 30
Is pressed together with the plunger 20 in a direction away from the coil 10. This separation distance H is determined by the plunger 2
It is limited by a stop ring 21 fixed to the rear end of the 0.

The plunger 20 may be formed of a hollow pipe as long as it has a magnetic material at least in its outer peripheral portion.

[0019]

According to the present invention, as described above, the magnet assembly is attached to the plunger of the solenoid, and this assembly is constituted by the magnetic material cup and the ring-shaped permanent magnet, and the opening peripheral edge of the cup is projected from the ring-shaped permanent magnet. As a result, magnetic lines of force are concentrated on the periphery of this opening and exert a strong adsorption force, so it operates by a small amount of momentary energization, power consumption can be saved, and reliable and strong operation and holding force are obtained. Guaranteed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an example of a solenoid according to the present invention.

FIG. 2 is a perspective view showing a magnet assembly of the above.

[Explanation of symbols]

 1 Solenoid 10 Solenoid Coil 11 Frame 12 Frame 13 Center Hole 14 Plunger Guide 15 Plunger Guide 16 Magnetic Material 20 Plunger 21 Stop Ring 22 Color 30 Magnet Assembly 31 Magnetic Material Cup 32 Ring-shaped Permanent Magnet 33 Opening Edge 40 Coil Spring

Claims (1)

Claims: 1. A solenoid coil, a plunger in which the center of the coil is axially movable, and a magnet assembly attached to the plunger so as to face the front end of the coil. The magnet assembly is composed of a spring that presses the magnet assembly away from the coil, and a magnetic body provided at the front end of the coil that faces the magnet assembly.
A solenoid having a ring-shaped permanent magnet and a magnetic material cup covering the ring-shaped permanent magnet, the opening peripheral edge of the cup facing the magnetic material and slightly protruding from the ring-shaped permanent magnet.