JPS6317211Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of the plunger return mechanism in a self-returning monostable solenoid, in which the plunger is returned using the magnetic force of a self-holding permanent magnet without using a spring. Regarding a self-returning monostable solenoid.

Generally, in a self-return type monostable solenoid, the plunger 2 is self-reset by the elasticity of a spring 1, as shown in FIG.

That is, by energizing the excitation coil 3, the plunger 2 is moved against the fixed iron core 4 against the elasticity of the spring 1.
After being attracted, the excitation current is cut off and the plunger 2 is held in the operating position by the magnetic force of the permanent magnet 5.

Next, when returning the plunger 2, a current in the opposite direction of the excitation coil 3 is applied for a short time to cancel the magnetic force of the permanent magnet 5, and the elasticity of the spring 1 moves the plunger 2 to its original position. There is.

However, in all conventional self-returning monostable solenoids of this type, the spring 1 is used to return the plunger 2, resulting in many inconveniences as described below. .

First, as the number of operations of the solenoid increases, the spring 1 suffers from metal fatigue, and its elastic force changes, making the operation of the solenoid unstable or, in the worst case, causing it to break.

Furthermore, since the spring 1 is separately assembled, the number of steps involved in machining increases, and it becomes extremely difficult to downsize the solenoid itself.

Furthermore, when the plunger 2 is operated by suction, the spring 1 is moved in proportion to the amount of movement of the plunger.
As the elastic reaction force increases, the plunger 2 is likely to be braked and its operation becomes slow, and
Since the self-holding force also needs to be increased accordingly, the permanent magnet 5 becomes larger.

Moreover, when returning the plunger 2, the return force gradually decreases as the spring 1 expands.
There are drawbacks such as a reduction in return speed.

The purpose of this invention is to eliminate the above-mentioned drawbacks of conventional self-returning monostable solenoids. The purpose of the present invention is to provide a self-returning monostable solenoid that is capable of self-returning.

Hereinafter, the details will be explained based on an embodiment of the present invention shown in FIGS. 2 and 3.

It should be noted that the present invention is not limited to the configurations of the embodiments, but can be modified as appropriate within the scope of the invention.

FIG. 2 is a schematic cross-sectional view showing the suction operation state of the solenoid according to the present invention, and FIG. 3 is a schematic cross-sectional view showing the return state.

In the figure, reference numeral 6 denotes a yoke having a substantially U-shaped cross section, and a bobbin 8 having an excitation coil 7 wound thereon is disposed and fixed at the front inside of the yoke. A guide pipe 9 made of a non-magnetic metal or a synthetic resin such as Teflon is inserted inside the bobbin 8 . Further, the front end 8a of the bobbin 8 has a tapered recess 10 at the end.
A fixed iron core having a shape a is inserted, and one end thereof is fixed to the end plate 6a of the yoke 7 by caulking or the like.

11 is a plunger slidably inserted into the guide pipe 9, and the front end (suction side)
has a tapered shape that fits into the tapered recess 10a of the fixed iron core. Further, the rear end (return side) of the plunger is also formed into a tapered protrusion 11a. 12 is an operating rod made of non-magnetic material.

13 is a permanent magnet made of ferrite, alnico, etc. for self-holding, and is located inside the rear part of the yoke 6 and is attached to the plunger 1 on the outside of the bobbin end plate 8b.
The arrangement is fixed so that comrades of the same polarity face each other with 1 in between. Note that the number of permanent magnets 13 may be two or more, and furthermore, it may be a ring-shaped magnet.

Reference numeral 14 denotes a return auxiliary yoke that is disposed facing the tapered protrusion 11a of the plunger 11 at a distance corresponding to the stroke L, and its end is fixed to the yoke end 6b. Further, the tip of the auxiliary yoke 14 has a tapered recess 14a that fits into the tapered protrusion 11a of the plunger.
is formed.

By combining the shapes of the rear end portion of the plunger 11 and the auxiliary yoke 14 into a tapered shape as described above, it becomes possible to take a considerably large stroke L.

In FIGS. 2 and 3, 15 is a support plate made of non-magnetic material, and 16 is a yoke for the permanent magnet.

Next, the operation of the solenoid will be explained.

Referring to FIG. 3, the plunger 11 is now in the return state, and the plunger has a permanent magnet 13.
A constant return force F is given by the magnetic flux Φ ₀ .

Next, when a pulsed excitation current is passed through the excitation coil 7 in a predetermined direction, an attraction force P ₀ in the direction of arrow A is actuated by the magnetic force caused by the excitation current, and this attraction force P ₀ is a return force F of the permanent magnet. By overcoming this, the plunger 11 is attracted to the fixed iron core 10 side.

After the plunger 11 is attracted, the excitation current is cut off and the permanent magnet 13 is turned off as shown in FIG.
The plunger 11 is held in the operating state with a constant holding force P ₁ by the magnetic flux Φ ₁ in the direction of arrow B from .

At this time, a part of the magnetic flux of the permanent magnet 13 becomes leakage magnetic flux Φ ₂ and also passes in the direction of arrow (c).
A slight restoring force F ₁ is exerted by the magnetic flux Φ ₂ .

When returning the plunger 11, a pulsed current in the opposite direction is applied to the excitation coil 7, and the magnetic flux Φ ₁ ' caused by the pulsed current causes the permanent magnet 1
Demagnetize the magnetic flux Φ ₁ of 3. Then, the holding force P ₁
is lost, and the leakage flux Φ 1 ′ _L ′ of the magnetic flux Φ ₁ ′ due to the reverse pulse is added to the leakage magnetic flux Φ ₂ passing through the permanent magnet 13 → the tapered projection 11a of the plunger → the auxiliary yoke 14 → the rear end _6b of the yoke. By applying this force, the plunger 11 has a return force F ₀ and the auxiliary yoke 14
It is pulled to the side and returns to the state shown in Figure 3.

Since the present invention has the above-described configuration, it has many excellent effects as described below.

(1) Since the plunger self-returns using the magnetic force of the self-holding permanent magnet without using a spring, there is no chance of breakage or malfunction due to spring fatigue. The structure and assembly are also simplified, making it possible to downsize the solenoid and significantly reduce manufacturing costs.

(2) Even when the plunger 11 is in suction operation,
Since the return force F is drastically reduced in inverse proportion to the square of the plunger travel distance, the plunger 11 is attracted to the fixed core very quickly, and compared to the case where a spring is used, a permanent magnet for self-holding is required. It can also be downsized.

(3) Even during the return operation of the plunger 11,
In addition to the leakage magnetic flux Φ ₂ of the permanent magnet 13, the leakage portion Φ _1L ′ of the magnetic flux Φ ₁ ′ due to the demagnetizing pulse current acts effectively, and a strong initial return force F ₀ is obtained.
Further, the tapered protrusion 11a of the plunger 11
As it moves toward the auxiliary yoke 14, the return force increases, and the plunger 11 returns to its original state at an extremely high speed.

As mentioned above, the present invention is completely new and original, and has extremely high practical utility.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing an example of a conventional self-resetting monostable solenoid. FIG. 2 is a schematic cross-sectional view showing the self-resetting monostable solenoid according to the present invention in an adsorption operating state, and FIG. 3 is a schematic cross-sectional view showing the returning state. L...stroke, 6...yoke, 6a...yoke end plate, 6b...yoke end, 7...excitation coil, 8...bobbin, 8a...front end of bobbin, 9
... Guide pipe, 10 ... Fixed iron core, 11 ... Plunger, 11a ... Tapered protrusion of plunger, 12 ... Operating rod, 13 ... Permanent magnet, 14
...Auxiliary yoke for return, 14a...Tapered recess of the auxiliary yoke.

Claims (1)

[Claims for Utility Model Registration] (1) An excitation coil 7 is installed inside the yoke 6, which has a substantially U-shaped cross section.
A bobbin 8 wound with A permanent magnet 13 is fixed to sandwich the slidably inserted plunger 11 so that the same polarity faces each other, and a return auxiliary yoke is fixed to the end 6b of the yoke at a distance of stroke L in front of the plunger 11. 14 is arranged, and the plunger 1 is moved by the magnetic force of the permanent magnet 13.
1. A self-returning monostable solenoid characterized by self-returning. (2) The tip of the plunger 11 has a tapered protrusion 1
1a, and a tapered recess 14 in which the return yoke 14 is fitted with the plunger tip.
A self-returning monostable solenoid according to claim 1 of the utility model registration claim a.