JPH0211767Y2 - - Google Patents

Description

[Detailed explanation of the idea] (a) Technical field This invention relates to a self-retaining solenoid.

A DC solenoid surrounds a coil with a ferromagnetic bracket, and a ferromagnetic plunger is installed in a sliding tube inside the coil so that it can move forward and backward.By energizing the coil, the bracket and plunger are magnetized, and the plunger is rotated around the shaft. It is designed so that it can be displaced in the direction and held at the displaced position.

(b) Definition The state in which the plunger is attracted to the ferromagnetic stopper fixed in the through hole of the bracket is called the attracted state.

The state in which the plunger is separated from the stopper and in the forward position is called the return state.

The movement of the plunger from the suction state to the return state is called return operation. The movement from the return state to the suction state is called suction operation.

A common solenoid that has been used for a long time uses a spring to pull out a plunger and return it to its original position, and the spring force maintains the state.

The suction operation is performed by energizing the coil and magnetizing the plunger. The suction state is maintained by continuing to energize.

On the other hand, a self-holding type refers to one that does not require spring force or coil power to maintain a certain state. Permanent magnets are used for this purpose.

There are three types of self-retaining solenoids: monostable, bistable, and bistable.

The monostable type allows only the attracted state to be maintained by the magnetic flux of the permanent magnet, and there is no need to continue energizing the coil to maintain this state.

The bistable type has two coils in a bracket and a permanent magnet in the middle of the bobbin. A current is momentarily applied to one of the coils to cause attraction or return operation. The attraction state and the return state are completely symmetrical and there is no distinction, and both states can be maintained by the action of the permanent magnet.

A bistable type refers to one that can be held in both the attracted and returned states by the magnetic flux of a permanent magnet, but has different stability due to its asymmetrical state. The coil is not divided into two parts, and the permanent magnet is not in the middle of the bracket, but is offset to one side. Although the suction state is extremely stable, the stability of the return state is low.

The present invention relates to an improved self-retaining, bistable solenoid.

(C) Bracket structure The bracket is a ferromagnetic case that surrounds the coil, sliding tube, and plunger, and also serves as a magnetic path for guiding the magnetic flux generated by the magnetization of the coil.

The conventional bracket structure will be explained.

It has a structure in which soft iron is folded into a U-shape and both ends are connected to a square front yoke.
There are notches on all four sides of the front yoke, insert the protrusion at the tip of the bracket into the notch, tap the protrusion,
Caulk to secure the bracket and front yoke.

This is fine for ordinary non-self-holding solenoids and monostable self-holding solenoids.

There is also a bracket structure in which a front yoke is attached to a pentahedron made by cutting soft iron into four pieces and bending them into four pieces. This was the first thing that the inventor came up with. Since the coil is surrounded by ferromagnetic material on all sides, leakage magnetic flux is reduced.

In the case of a bistable or bistable self-retaining solenoid, a stop plate must be fixed in front of the front yoke to define the return state.

In the case of bistable solenoids, a combination of two U-shaped brackets is currently manufactured. This puts the coil and plunger into two U-shaped brackets.

Place the same brackets facing each other and twist them 90 degrees, then swage the protrusions on the ends to secure the two brackets together.

For example, it has a structure like Utility Model Publication No. 52-50356 (announced on November 15, 1976) "Latching Solenoid".

In any case, the brackets are assembled by inserting the end protrusions into the mating notches and then crimping them together.

A bistable self-retaining solenoid is a permanent magnet.
It maintains the suction state and return state, but is not completely symmetrical, such as bistable.

Since the return force is often weak compared to the suction force, one that does not impose a load on the return direction is selected.

Further, a plunger stop plate is usually not provided to define the return position.

Even if a stop plate is provided, the return operation is often braked by some kind of stop mechanism on the load side. The stop plate often does not receive the entire impact of the plunger.

For this reason, with conventional solenoids, fixing the stop plate that receives the return operation to the bracket has not been much of a problem.

Therefore, the stop plate is fixed to the bracket by caulking in the conventional manner.

(d) Disadvantages of conventional bracket structure If such a bistable self-holding solenoid is repeatedly operated to attract and return without applying a load,
During the return movement, the plunger collides with the stop plate.

After about 500,000 operations, the caulking of the stop plate will loosen. Solenoids must withstand approximately 50 million repetitive movements. This is insufficient strength.

The problem lies in the way it is fixed by caulking. No matter how hard you bite down, the repeated impact will deform and loosen the caulked parts.

There are no problems with the suction operation. This is because the bracket is fixed to some kind of mounting seat with screws, and the plunger directly collides with the back surface of the bracket.

This disadvantage arises because the bracket and front yoke are fixed by caulking. This is because the bracket has a U-shaped cross section and is open at the front, so the front yoke must be firmly fixed by caulking.

(E) Structure of the present invention The present invention has a bracket that does not have a U-shaped cross section.
It has a square-shaped cross section that surrounds it on all sides. Holes are provided in the front and rear end surfaces of the bracket for the front and rear of the plunger to pass through. A plunger stop plate having a hole so small that the plunger cannot pass through is fixed to the bracket with a screw.

The bracket stopper plate can be screwed to the bracket, or it can be screwed to a new front yoke provided on the back side of the bracket. Furthermore, it is also possible to drill a female screw hole in the bobbin and screw it into this hole.

(F) Embodiment The configuration of a self-holding solenoid according to an embodiment of the present invention will be explained with reference to the drawings.

FIG. 1 is an exploded perspective view of a solenoid according to an embodiment.

This solenoid includes bracket 1, bobbin 2,
plunger 3, stopper 4, front yoke 5,
It consists of a plunger stop plate 6, permanent magnets 7, 7, an excitation coil 8 wound around a bobbin, a set screw 45, etc.

The bracket 1 is formed by press-molding a plate of ferromagnetic material such as soft iron into a rectangular frame shape with a square cross section. Unlike conventional products, it does not have a U-shaped cross section with one side open.

It has a square frame shape, and a rectangular parallelepiped bobbin fitting space 9 is created inside.

The bracket 1 includes a rear plate part 10, side plate parts 11, 11 on both sides following this, and a front plate part 12, following this.
It consists of 12 pieces, but it is made from a single bent plate and is not welded. The bends are at right angles. The rear plate part 10 and the front plate part 12 are parallel.

Since the precision of press forming has improved, the perpendicularity of the bent portion and the parallelism of the rear plate portion 10 and the front plate portion 12 are extremely good. These precisions are essential conditions for the plunger to operate smoothly.

A stopper fixing hole 13 is bored in the center of the rear plate portion 10.

A plunger through hole 14 is bored in the center of the front plate parts 12, 12. Since the front plate part 12 is obtained by bending the tip of the side plate part 11 by about half the width of the rear plate part 10, the abutting part 1 is exactly aligned along the center line.
8 is occurring. The gap is less than 1mm.

Therefore, the plunger through hole 14 is formed by aligning semicircular notches along the diameter.

Screw holes 15 are bored in the four corners of the front plate part 12.

Mounting screw holes 16, . . . are bored in the side plate portion 11. This is for fixing the bracket 1 to a suitable mounting seat plate with screws.

In this example, the height of the bracket is 35 mm, the vertical and horizontal widths are 21 mm, 25 mm, and the thickness is 2 mm.

The functions of the bobbin 2 include being a cylinder for winding an excitation coil, being a sliding member that guides the plunger 3 in the axial direction, and holding the front yoke 5 when holding the permanent magnets 7. be.

Made of plastic like sliding properties.

The front part of the bobbin 2 is a rectangular frame part 20, and the rear part is a cylindrical part 21 for winding a coil. Further, in the direction of the central axis, there is a through hole having a constant inner diameter, and the plunger 3 moves forward and backward within this sliding cylinder portion 22.

A flat space surrounded by the front end of the sliding cylinder part 22 and the frame part 20 is a front yoke fitting space 23 into which the front yoke 5 is inserted. There are shallow holes 24 at the four corners of this so that the tips of the set screws 45 do not touch them.

Furthermore, there are two magnet housing holes 25, 25 on the sides of the frame 20 of the bobbin 2, into which the permanent magnets 7, 7 are fitted. The permanent magnets 7, 7 are inserted into the magnet housing holes 25, 25 so that the same poles face each other.

In order to perform the return operation, it is necessary that the permanent magnet 7 and the front yoke 5 be separated from each other in the front and rear direction. Further, two opposite sides of the front end of the frame portion 20 are chamfered 28 so as to fit into the inside of the bracket 1.

A bobbin cylindrical portion 21 from which three (or two) lead wires 26 are drawn out from the excitation coil 8.
A flange portion 27 is formed at the rear end opening.

The plunger 3 is a cylindrical ferromagnetic material and has a non-magnetic push rod 30 fixed to its rear end. If necessary, a female screw hole 31 may be provided in front of the plunger 3, into which an output rod (not shown) connected to some kind of load may be screwed. A push rod 30 may also operate the load.

The stopper 4 is made of a ferromagnetic material, and is fitted into a stopper fixing hole 13 in the rear plate portion 10 of the bracket 1 and fixed by caulking. This has a large diameter part 32 and a small diameter part 33, and the small diameter part 33 is inserted into the stopper hole 13 and caulked.

The inner periphery has a rod through hole 34 with a conical surface.

The front yoke 5 is a square plate made of ferromagnetic material, and has a sliding tube through hole 36 in the center and female screw holes 37 in the four corners. This is made from soft iron plate.

The plunger stop plate 6 is a non-magnetic plate with an output rod through hole 40 bored in the center. This is narrower than plunger 3 and does not allow the plunger to pass through. The return movement of the plunger is thereby stopped.

Screw holes 41 in the four corners of the plunger stopper plate 6
is worn.

Explain the assembly order.

Figure 2 is a plan view of the assembled solenoid.
Figure 3 is a cross-sectional view of Figure 2, and Figure 4 is a -
A portion of a cross-sectional view is shown.

The permanent magnets 7, 7 are inserted into the magnet housing holes 25, 25 of the bobbin 2 so that the same poles face each other. The front yoke 5 is fitted into the front yoke fitting space 23.

Thereafter, the bobbin 2 is inserted into the bobbin fitting space 9 of the bracket 1 from the side.

Plunger through hole 14 and sliding tube part 2 of bobbin 2
2. The stopper holes 13 are aligned in a straight line.

The stopper 4 is dropped through the plunger through hole 14 with the small diameter portion 33 facing down.

The stopper 4 fits into a stopper fixing hole 13 in the rear plate portion 10 of the bracket 1. Support the stopper 4 from the front with a suitable jig, caulk the small diameter portion 33,
Attach to bracket 1.

Next, move the plunger 3 so that the push rod 30 faces the stopper 4, and insert the plunger through hole 14 of the bracket 1 and the sliding cylinder part 22 of the bobbin 2.
insert it into

The plunger stop plate 6 is stacked on the front plate portion 12 of the bracket 1.

Insert the set screws 45, . By strongly tightening, the plunger stop plate 6, bracket 1, and front yoke 5 are integrated.

The tip of the set screw 45 protrudes below the front yoke 5, but since there is a through hole 24, the bobbin 2
Do not pry the surface.

(g) Effects The restored state is shown in Figure 3. This state is stable. The plunger 3 is stopped against a plunger stop plate 6.

The magnetic flux of the permanent magnet 7 is the first half of the plunger 3,
front yoke 5, front plate portion 12 of bracket 1,
It returns to the permanent magnet 7 through the front half of the side plate parts 11, 11 of the bracket.

In the suction state, the rear end of the plunger 3 is in contact with the stopper 4, as shown by the broken line.

After repeating return and suction many times, plunger 3
collides with the plunger stop plate 6 and stopper 4 many times.

Since the bracket 1 is fixed to the mounting seat at the screw hole 16 by a screw (not shown), the impact force on the stopper 4 does not pose much of a problem.

The problem is the impact force on the plunger stop plate 6 during the return operation.

However, in the present invention, since the plunger stopper plate 6 is screwed rather than caulked, it will not loosen due to repeated impacts.

In an experiment, the caulked structure loosened after 500,000 operations, but this invention did not loosen even after 50 million operations.

(H) Other Embodiments In this example, a ferromagnetic front yoke 5 is provided on the back surface of the front plate portion 12 of the bracket 1, and a set screw 45 is fixed through the female threaded hole 37.

The front yoke 5 is for reducing magnetic resistance, and can be omitted. In that case, a female screw hole is cut in the front plate part 12 of the bracket 1, and the tip of the set screw 45 is screwed into the hole.

Since the front yoke fitting space 23 is not required in the bobbin 2, this part becomes a solid body, and it is also possible to cut a female screw hole in the bobbin and fix the set screw 45 therein.

Further, although the plunger stopper plate 6 is made of a non-magnetic material (such as stainless steel), it may be made of a ferromagnetic material. If it is made of ferromagnetic material, the return state will be more stable. Instead, more coil current is required for the suction operation.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a solenoid according to an embodiment of the present invention. FIG. 2 is a plan view of the assembled state. Third
The figure is a - sectional view in Fig. 2. FIG. 4 is a partial view of the - section in FIG. 2. 1...Bracket, 2...Bobbin, 3...Plunger, 4...Stopper, 5...Front yoke, 6...Plunger stop plate, 7...Permanent magnet,
8... Excitation coil, 9... Fitting space, 10... Rear plate part, 11... Side plate part, 12... Front plate part, 13...
...stopper fixing hole, 14...plunger through hole,
15...Screw through hole, 16...Mounting screw hole, 18
...Abutment part, 20...Frame part, 21...Cylindrical part,
22...Sliding tube portion, 23...Front yoke fitting space, 24...Snow hole, 25...Magnet accommodation hole,
26... Lead wire, 27... Flange, 28... Chamfer, 30... Push rod, 31... Female screw hole,
32... Large diameter part, 33... Small diameter part, 34... Rod through hole, 36... Sliding cylinder part through hole, 37... Female screw hole, 40... Output rod through hole, 41... Screw through hole. hole.

Claims (1)

[Scope of utility model registration request] A bracket 1 made of a ferromagnetic plate bent into a rectangular frame shape so as to have a square cross section, a bobbin 2 provided in the bracket 1, an excitation coil 8 wound around the bobbin 2, and an excitation coil 8. A plunger 3 made of ferromagnetic material that is provided to be able to move forward and backward in a sliding tube that penetrates the coil 8, and a stopper hole 13 in the rear plate portion 10 of the bracket 1.
A stopper 4 made of a ferromagnetic material is fixed to stop the attracting operation of the plunger 3, and permanent magnets 7, 7 are provided in front of the bracket 1 and separated from the front plate part 12 so that the same poles face each other with the plunger 3 in between. Then, by means of a set screw 45 on the outside of the front plate part 12 of the bracket 1, it is screwed into the front yoke 5 or bobbin 2 provided on the front plate part 12 of the bracket or the back surface of the front plate part 12 of the bracket. A self-holding solenoid characterized by comprising a plunger stop plate 6 for stopping the return operation of the plunger 3 that has been attached.