JPH08200537A - Solenoid - Google Patents

Abstract

PURPOSE: To approximate the force of attraction for the stroke of a plunger to an energizing force to meet the various requirements so as to ensure the operation of the plunger by providing a nonlinear spring at an energizing portion. CONSTITUTION: In a solenoid S so designed that a plunger 5 is energized by an energizing portion 10 and that a plunger ring 8 is fitted to the outside end of the plunger 5 so that by bringing a yoke 1 close to the plunger ring 8 during the attraction of the plunger 5, the plunger 5 is held by a holding current, the energizing portion 10 comprises long and short coil springs 11, 12. As a result, at the attracting position of the plunger 5 the plunger 5 is energized by the long and short coil springs 11, 12, and the short coil spring 12 loses its energizing force at a point halfway between the attracting position and maximum stroke. Therefore, the solenoid is made to have a nonlinear spring constant with which the energizing force varies in two steps as to the stroke, and the energizing force can be approximated to an attracting force produced by an exciting current.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to solenoids.

[0002]

2. Description of the Related Art In a conventional solenoid, a plunger is separated from a fixed iron core having a permanent magnet attached thereto by a spring bias, and a coil is energized to fix the plunger so that a magnetic force in the same direction as the permanent magnet is generated. Attract to the iron core side, hold the plunger in the attraction position with the magnetic force of the permanent magnet,
On the other hand, the coil is energized so as to generate a magnetic force in the opposite direction to the permanent magnet, and the plunger is separated from the fixed iron core by the biasing of the spring.

As disclosed in Japanese Patent Laid-Open No. 2-133906, the magnetic resistance between the fixed iron core and the plunger at the attracting position is reduced, and the magnetic force and residual magnetism generated by the holding current applied to the coil causes Some solenoids are designed to be miniaturized by allowing the plunger to be held in a fixed state on a fixed iron core and eliminating the need for a permanent magnet.

When the solenoid is used in a diaphragm type valve device, a seal member such as rubber is attached to the end of the plunger which comes in contact with and separates from the pilot valve seat of the diaphragm, and when the valve is closed, the same seal is used. The member is pressed against the pilot valve seat by the biasing of the spring.

[0005]

However, in order to ensure the valve closed state, it is necessary to strengthen the biasing force of the spring to increase the crimping force between the seal member and the pilot valve seat. When the force is increased, it becomes difficult to hold the plunger at the attracting position in order to maintain the valve open state with a weak holding current. Therefore, there is a problem that the holding current needs to be increased.

Further, it is necessary to increase the stroke of the plunger in order to compensate for the deterioration of the seal member with time, and it is necessary to provide a sufficient crimping force even with such a large stroke. Because there is
The above problems are exacerbated.

[0007]

According to the present invention, a plunger biased outward by a biasing portion is slidably inserted into a cylindrical coil whose outer periphery is surrounded by a yoke, and The plunger is attracted to the inside by energization, and the attraction of the plunger is released by shutting off the above energization.In addition, the plunger ring is fitted to the outer end of the plunger, and the yoke and the plunger ring are brought close In a solenoid configured to hold an attracted state of a plunger by a holding current at least, a solenoid having a non-linear spring in the urging portion is provided.

Another feature is that the urging portion is composed of two long and short coil springs.

[0009]

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

1 and 2 show a diaphragm valve V provided with a solenoid S according to the present invention. The solenoid S has a substantially U-shaped yoke 1 and a plunger which closes an opening end of the yoke 1 and is a plunger. Magnetically permeable substrate 3 having insertion hole 2
A fixed iron core 4 fixed to the inner surface of the central portion of the yoke 1 facing the plunger insertion hole 2; and a bobbin 6 arranged on the same axis of the fixed iron core 4 and also serving as a guide for the plunger 5.
A coil 7 wound around the outer circumference of the bobbin 6, a plunger 5 slidably inserted into the bobbin 6, a plunger ring 8 fixed to the tip of the plunger 5, a plunger ring 8 and a bobbin. 6 and a stepped portion 9 and a biasing portion 10 interposed therebetween.

The plunger ring 8 is substantially disk-shaped and has a larger diameter than the plunger 5. The plunger ring 8 is arranged so as to be close to the substrate 3 at a suction position of the plunger 5 with a slight gap.

Particularly, the urging portion 10 is composed of a short coil spring 12 having a large winding diameter and a short spring length, and a long coil spring 11 having a small winding diameter and a long spring length, and the long coil spring 11 is always a plunger. The short coil spring 12 is attached to the plunger ring 8 by contacting the ring 8 and the stepped portion 9 and biasing the plunger 5, and the plunger ring 8 and the stepped portion are attached to the plunger ring 8 at the attraction position of the plunger 5. Although the plunger 5 is urged by coming into contact with the portion 9, the urging force is lost by separating from the stepped portion 9 in the middle of the suction position of the plunger 5 and the stroke end.

A pilot valve body 20 made of a flexible material such as rubber is fitted on the tip end surface of the plunger 5.

The diaphragm valve V is mainly composed of an upper shell 22 and a lower shell 23 which are continuously provided on the lower surface of the base plate 3.
And a diaphragm 24 and a movable valve body 25.

The upper shell 22 has a substantially cylindrical shape, the upper end surface of which is in close contact with the lower surface of the substrate 3 and the lower surface of which forms a diaphragm pressing surface 26.

The lower shell 23 is composed of an annular inflow passage 27 connected to an external water source and an outflow passage 28 concentrically provided inside the inflow passage 27. valve seat
Forming 29.

The diaphragm 24 is made of a flexible material such as rubber with cloth and is formed into a substantially disc shape.
The outer peripheral edge of 3 holds the outer peripheral edge of the diaphragm 24 to maintain watertightness, and the upper surface of the diaphragm 24 and the upper shell.
22 and the lower surface of the substrate 3 form a diaphragm back chamber 31.

The central portion of the diaphragm 24 is also formed thick, and the lower surface of the central portion functions as the main valve body 32,
The valve function is performed by contacting and separating from the main valve seat 29.

Further, the diaphragm 24 is formed with an orifice 33 which connects the diaphragm back chamber 31 and the inflow passage 27.

The movable valve body 25 is formed in a substantially cylindrical shape having a flange portion 34 for mounting the diaphragm 24 in the middle thereof, and the upper end portion of the movable valve body 25 is reduced in diameter to form the pilot valve body 20 on the lower end surface of the plunger 5. It forms a pilot valve seat 21 that contacts and separates, and is attached to the center of a diaphragm 24.

The embodiment of the present invention is constructed as described above, and when the coil 7 of the solenoid S is not energized, as shown in FIG. The pilot valve seat 21 is closed by the pilot valve body 20 located at the position, and the pressure of the diaphragm back chamber 31 is increased by the pressure water from the external water source flowing from the orifice 33,
The diaphragm 24 moves downward, the main valve seat 32 closes the main valve seat 29 to close the valve, and this state is maintained.

When the coil 7 is energized, as shown in FIG. 2, the magnetic force generated in the coil 7 causes the plunger 5 to be attracted to the fixed iron core 4 and is positioned above to open the pilot valve seat 21 to open the pilot valve. Seat 21 to diaphragm back room
The pressurized water in 31 flows out, the diaphragm 24 moves upward, the main valve seat 29 opens, and the valve is opened.

After that, when the energization is completely stopped, the plunger 5 moves downward away from the fixed iron core 4 by the urging of the urging portion 10, the pilot valve seat 21 closes, and the external water source flowing from the orifice 33 flows. The pressure in the diaphragm back chamber 31 is increased by the pressure water from the diaphragm 24, and the diaphragm 24 moves downward to close the main valve seat 29 with the main valve body 32 and return to the closed state, but the coil 7 holds it weakly. By supplying an electric current, it is possible to hold the state where the plunger 5 is attracted to the fixed iron core 4 by the magnetic force and residual magnetism generated in the coil 7 by the holding current.

As described above, the plunger 5 is fixed to the fixed iron core 4
In the state of being attracted to, the plunger ring 8 and the substrate 3 are close to each other with a slight gap therebetween, and the magnetic resistance of the magnetic circuit composed of the fixed iron core 4, the yoke 1, the plunger ring 8 and the substrate 3 is Since it becomes smaller, the holding current can be made very small.

That is, since a ferromagnetic material generally has hysteresis, there is a relationship between the exciting current and magnetism as shown in FIG. 3, and once the ferromagnetic material is excited, the exciting current is cut off. The magnetism indicated by the point b on the hysteresis curve h remains, but when the exciting current is cut off in the actual solenoid S, the attraction force (magnetic force) acting on the plunger 5 in the direction of the fixed iron core 4 is applied to the urging portion 10. The attraction force (point c) that is smaller than the urging force of the plunger 5 remains, and therefore the attracted state of the plunger 5 cannot be maintained only by the residual magnetism.

Therefore, a holding current is passed through the coil 7 to maintain the attracted state of the plunger 5. In the present embodiment, the plunger ring 8 is provided to reduce the magnetic resistance at the attracted position (to increase the permeance). Therefore, the slope of the straight line 40 connecting the point c and the origin approaches a right angle, and the straight line 40 passing through the point d set to be larger than the biasing force.
It becomes possible to weaken the holding current Ih indicated by the distance between the origin and the intersection 42 of the parallel line 41 with the X axis.

FIG. 4 shows the relationship between the suction force with respect to the stroke of the plunger 5 and the urging force with respect to the stroke. The urging force requires the following conditions.

When the excitation current is shut off and the valve is closed (at the maximum stroke), the plunger 5 is biased outward with a predetermined pressing force.

The urging force is smaller than the attraction force by the exciting current for opening the valve at all possible positions of the plunger 5.

The urging force when the valve is opened (stroke = 0) is larger than the attraction force due to the residual magnetism.

The urging force when the valve is opened (stroke = 0) is smaller than the attraction force when the holding current is applied.

However, in the conventional urging with a single spring, the relationship between the stroke and the urging force is linear. Therefore, if the condition of is satisfied, in the middle of the stroke as shown by the broken line, The biasing force exceeds the suction force, and the condition of is not satisfied.

Therefore, in the present invention, the urging portion 10 is constituted by the long and short coil springs 11 and 12, and at the attraction position of the plunger 5, both the long and short coil springs 11 and 12 urge the plunger 5, but the attraction position. Since the short coil spring 12 loses the biasing force at a point d between the maximum stroke and the maximum stroke, the biasing force has a non-linear spring constant that changes in two steps with respect to the stroke, as shown in FIG. Therefore, the biasing force can be approximated to the attraction force due to the exciting current.

As described above, by approximating the biasing force to the attracting force by the exciting current, it is possible to satisfy all the above conditions (1) to (4) as shown in FIG.

That is, the attraction force due to the exciting current exceeds the urging force in all states, and there is no state in which the urging force exceeds the attracting force as in the case of urging with a single spring. Is surely adsorbed.

In addition, since the urging force exceeds the attraction force due to the residual magnetism in the state where the current is completely cut off in all states, the plunger 5 is reliably disengaged by the current cutoff.

In the attracted state of the plunger 5, the attracting force by the holding current exceeds the urging force, so that the holding current can be made weak.

Therefore, when the diaphragm valve V is closed, the pilot valve body 20 can be pressed against the pilot valve seat 21 as necessary and sufficient, and the closed state can be reliably maintained.
When an exciting current is passed through the coil 7, the attraction force exceeds the urging force regardless of the position of the plunger 5, so the valve opening operation is ensured, and the attraction force due to the residual magnetism is exerted regardless of the position of the plunger 5. Since the urging force is higher than that, the valve closing operation is ensured, and since the magnetic resistance at the attracting position is reduced by providing the plunger ring 8, the valve opening state can be held with a weak holding current Ih. .

[0039]

According to the present invention, a plunger biased outward by a biasing portion is slidably inserted into a tubular coil whose outer periphery is surrounded by a yoke, and the coil is energized. It is configured to adsorb the plunger inside and to release the adsorption of the plunger by cutting off the energization.
In a solenoid in which a plunger ring is fitted to the outer end of the plunger and the yoke and the plunger ring are brought close to each other when the plunger is attracted to maintain the attracted state of the plunger by a weak holding current, Since the spring is provided, the biasing force can be approximated to the attraction force with respect to the stroke of the plunger, and various conditions required for the biasing portion can be satisfied to ensure the operation of the plunger.

Since the biasing portion is composed of two long and short coil springs, an appropriate non-linear spring can be applied to the biasing portion with a simple structure.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view (closed state) of a diaphragm valve equipped with a solenoid according to the present invention.

FIG. 2 is a vertical cross-sectional explanatory view (valve open state).

FIG. 3 is a graph showing the relationship between the exciting current and the attractive force.

FIG. 4 is a graph showing a relationship between a biasing force and a suction force with respect to a stroke.

[Explanation of symbols]

 S Solenoid 1 Yoke 5 Plunger 7 Coil 8 Plunger ring 10 Energizing part 11 Long coil spring 12 Short coil spring

Claims (2)

[Claims] 1. A plunger (5) biased outward by a biasing portion (10) is slidably inserted into a cylindrical coil (7) whose outer periphery is surrounded by a yoke (1). , The coil (7) is energized to adsorb the plunger (5) inside, and the energization of the coil (7) is cut off to desorb the plunger (5), and the plunger ring (5) is attached to the outer end of the plunger (5). 8), and when the plunger (5) is
In the solenoid (S) configured to bring the plunger ring (8) and the plunger ring (8) close to each other to hold the attracted state of the plunger (5), a non-linear spring is provided in the urging portion (10). Solenoid characterized by 2. The solenoid according to claim 1, wherein the biasing portion (10) is composed of two long and short coil springs (11) (12).