JPH04282804A - Latching solenoid - Google Patents

Abstract

PURPOSE:To obtain a magnetic attraction force of an intermediate region in a plunger stroke in the case of decreasing in size or increasing in the stroke of a latching solenoid. CONSTITUTION:A latching solenoid is composed by forming a protruding tapered part 4c of a plunger 4 of a flat part 4b of a columnar surface parallel at the base to a slide shaft and setting the length (L) of the part 4b with the length of an isolating distance as a maximum limit in a state that an isolating distance (S) between a latch 1a of a pole core 1 and a part 4a of the plunger 4 upon advancing of the plunger 4 is equal to an isolating distance (T) between the part 4c and a recessed tapered part 1b.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a latching solenoid used for driving faucets to open and close, and more particularly to a latching solenoid having a long stroke and improved suction characteristics over the entire stroke.

0002

2. Description of the Related Art A latching solenoid having a long stroke and used for opening and closing an automatic water faucet is operated by the magnetic attraction force of a coil having a pole core therein. The center of the coil forms a case that guides the sliding movement of the plunger, and one end of the coil is closed by the pole core, and the advanced plunger comes into contact with it.

[0003] The pole core has a latch portion that forms a plane perpendicular to the coil center axis, and the opposing abutment portion of the plunger abuts this latch portion. The center of the latch portion of the pole core forms a concave conical surface with a tapered portion that narrows in the advancing direction of the plunger.

A return spring is provided in the center of the plunger tip, and a convex conical surface is formed by a tapered portion that narrows toward the plunger tip. This convex taper portion has approximately the same taper angle as the taper of the concave taper portion of the pole core. When the plunger advances due to the latch current and the contact portion of the plunger abuts the latch portion of the pole core, the convex taper portion advances into the concave taper portion of the pole core. Due to the proximity of both tapered portions, a large magnetic attraction force acts on the plunger even when the plunger is retracted.

[0005]The suction force characteristic is such that the suction force increases with the amount of advance of the plunger, and reaches its maximum suction force when the abutting portion of the plunger comes into contact with the latch portion of the pole core, that is, at the time of latching.

The suction characteristics of the latching solenoid must satisfy both the linearity in which the suction force increases uniformly according to the amount of advance of the plunger, and the suction strength. It affects the dynamic characteristics and is important as a requirement to avoid latching errors.

[0007]There is a need for improved performance for the purpose of increasing operational reliability and expanding applications such as incorporation into equipment, and therefore, there is a need for larger strokes and smaller size.

In the case of downsizing, the suction force also decreases, making it difficult to operate over long strokes. Therefore, the taper portions of both the pole core and the plunger are extended so that a large suction force is applied even when the plunger retreats. By increasing the amount, suction characteristics are being improved using a method similar to increasing the stroke length.

In this case, when the convex taper part of the plunger advances into the concave taper part of the pole core, a gap is required to drain water from the concave part of the pole core, so the base part slides against the base of the convex part of the plunger. By forming the parallel portion made of a cylindrical surface parallel to the dynamic axis, the amount of advancement can be increased.

0010

[Problems to be Solved by the Invention] However, in a latching solenoid in which a long parallel portion is provided at the base of the plunger convex portion in order to increase the amount of advancement, the suction force when the plunger retreats increases, but the Since the suction force is insufficient in the intermediate advancing region, linearity of the suction force cannot be ensured over the entire stroke of the plunger from the retreat position to the latching position.

[0011]

[Means for Solving the Problems] In order to solve the above problems, the convex tapered part of the latching solenoid is a parallel part whose base is a cylindrical surface parallel to the sliding axis, and the length of this parallel part (L ) is a state in which the plunger advances and the distance (S) between the latch part of the pole core and the contact part of the plunger becomes equal to the distance (T) between the convex taper part and the concave taper part. The latching solenoid was constructed with the length of the separation distance at the maximum limit.

0012

[Operation] The position where the plunger is retracted, that is, the distance between the latch part of the pole core and the abutting part of the plunger (
In the range where S) is larger than the separation distance (T) between the opposing concave taper portion and convex taper portion of the pole core and plunger, this separation distance (T) is the minimum distance between the pole core and the plunger. As the plunger advances, the opposing area between the two increases, so that the suction force uniformly increases. Then the plunger advances,
When the separation distance (S) becomes equal to the separation distance (T), the separation distance (S) becomes the minimum distance between the pole core and the plunger, and as the plunger advances, the opposing distance between the two decreases. This uniformly increases the suction force.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing the relationship between a plunger and a pole core of a latching solenoid according to the present invention. FIG. 2 is a semi-longitudinal view of the latching solenoid.

A pole core 1 is disposed inside the coil 2, and a plunger 4 that can slide forward and backward with respect to the pole core 1 is provided in a case 3 forming a slide guide whose lower end is closed by the pole core 1. The outer periphery of the coil 2 is covered by a yoke 5 that forms a magnetic path by fixing the pole core 1 with a caulking fixing part 1c at one end thereof, and a magnet 6 is provided inside the yoke 5 at the upper part. A return spring (not shown) is provided inside the tip of the plunger 4.

The pole core 1 has a latch portion 1a that is a plane perpendicular to the central axis of the coil 2, and the latch portion 1a has a concave portion at its center. A tapered portion 1b is formed.

On the other hand, the tip of the plunger 4 forms a contact part 4a which is a flat surface that faces the latch part 1a of the pole core 1 and comes into contact with the latch part 1a when the plunger 4 advances. A parallel part 4b made of a cylindrical surface parallel to the sliding axis is formed at the center of the plunger 4a, and a tapered part 4c made of a convex conical surface that narrows toward the tip of the plunger is formed following this parallel part 4b.

The convex taper portion 4c has a taper angle substantially the same as that of the concave taper portion 1b of the pole core, and
In addition, the distance L from the contact part 4a to the tapered part 4c, which is the length of the parallel part 4b, is the distance between the latch part 1a of the pole core 1 and the contact part 4a of the plunger 4 when the plunger 4 advances. The length of the separation distance in a state where the distance (S) is equal to the separation distance (T) between the convex taper portion 4c and the concave taper portion 1b is set as the maximum limit.

The convex tapered portion 4a of the plunger 4
When the water enters the concave tapered part 1a of the pole core 1, a gap is required to drain water from the concave part of the pole core 1. Therefore, within the above conditions, the length of the parallel part 4b of the plunger 4 should be It is stipulated in consideration of securing the drainage function of water pushed out from the concave portion of the plunger 4 and securing the magnetic attraction force when the plunger 4 retreats.

Note that the convex taper portion may be provided on the pole core side and the concave taper portion may be provided on the plunger side.

The operation of the latching solenoid according to the present invention having the above structure will be explained. The plunger 4 advances due to the latch current, and the latch part 1 of the pole core 1
When the abutting portion 4a of the plunger 4 abuts on the abutting portion a, the convex tapered portion 4c advances into the concave tapered portion 1b of the pole core 1. Since the magnetic attraction force corresponds to the distance and opposing area between the pole core 1 and the plunger 4, the attraction force in that stroke is determined by the relationship between the plunger 4 and the pole core 4 depending on the advanced position.

FIG. 3 shows the relationship between the plunger and the pole core depending on the advanced position. (A) shows when the plunger is retracted, and (B) shows that the stroke of the plunger (S) is the distance between the tapered parts (T). (C) is a diagram showing when S is smaller than T.

(A) When the plunger 4 shown in the figure is retracted, that is, the stroke (S1) of the plunger is the concave taper portion 1b.
When the distance is greater than the separation distance (T1) between the plunger 4 and the convex tapered portion 4c, the shortest distance between the plunger 4 and the pole core 4 is T1.

[0024] Therefore, the suction force mainly depends on this T1.
It occurs between the taper parts of the pole core 1 and the plunger 4, which face each other with To increase.

(B) When the plunger stroke (S2) in the figure is equal to the separation distance (T2) between the tapered parts, the connection position C between the parallel part 4b and the tapered part 4c of the plunger 4 is at the latch part of the pole core 1. Since it does not advance beyond position A,
The shortest distance between plunger 4 and pole core 4 is T2 and S2.

Therefore, the suction force is mainly applied to the entire range from A to B between the two tapered parts facing each other with T2 in between, and the latch part 1a of the pole core 1 facing with S2 in between.
and the contact portion 4a of the plunger 4.

(C) The stroke (S3) of the plunger shown in the figure corresponds to the distance (
T3), the shortest distance between the plunger 4 and the pole core 4 is S3.

On the other hand, between the two tapered parts facing each other with T3 in between, the separation distance T3 becomes larger than S3, and the two tapered parts from A to C may be out of the opposing range, and in this case, the suction The increase in force becomes smaller.

Therefore, the suction force is mainly determined between the latch portion 1a of the pole core 1 and the contact portion 4a of the plunger 4, which face each other with S3 in between, and increases uniformly as S3 decreases.

FIG. 4 is a characteristic diagram comparing the suction force of a latching solenoid, and FIG. 5 is a characteristic diagram comparing the suction force of a long stroke type latching solenoid. The horizontal axis S of the characteristic diagram is the stroke, and the vertical axis F is the suction force, and the units are mm and gf, respectively.

Line C1 in FIG. 4 shows actually measured characteristics of the miniaturized latching solenoid according to the present invention, and lines C2 and C3 show actually measured characteristics of conventional latching solenoids with taper angles of 30 degrees and 28 degrees. Diagram C1 shows linearity in the middle stroke region compared to diagrams C2 and C3.

Line C4 in FIG. 5 shows the measured characteristics of the long-stroke latching solenoid according to the present invention, and lines C5 and C6 show the measured characteristics of the conventional long-stroke latching solenoid and the current latching solenoid. Diagram C4 shows linearity in the middle stroke region compared to diagrams C5 and C6.

FIG. 6 shows the magnetic circuit model of the latching solenoid, (A) is its equivalent electric circuit diagram, (B) is the equivalent electric circuit diagram for attraction force analysis, and (C) is the circuit element diagram. It is a sectional view showing correspondence.

Each circuit element in the equivalent electric circuit diagram in FIG. (A) is as shown in FIG. is the current of circuit B consisting of the plunger 4, the upper end 5b of the yoke 5, and the magnet 6, and E1 is the current of the magnet 6.
E2 is the electromotive force corresponding to coil 2, R
11 is a resistance due to the plunger 4 of circuit A, R12 is a resistance due to the plunger 4 of circuit B, R2 is a resistance due to the gap between the plunger 4 and the pole core 1, R3 is a resistance due to the pole core 1, R41 is a resistance due to the yoke 5 of circuit A, R4
2 is the resistance due to the yoke 5 of circuit B, R5 is the resistance due to the magnet 6, R6 is the resistance due to the gap between the magnet 6 and the plunger 4, and R7 is the resistance due to the gap between the plunger 4 and the yoke 5.

The equivalent electric circuit diagram in figure (B) is a diagram that extracts only the gap portion that creates a large resistance among the circuit elements in figure (A), and it is possible to evaluate the suction force of the latching solenoid using this equivalent circuit. can. This is plunger 4
This is also reasonable because the magnetic permeability of the pole core 1 and yoke 5 is hundreds to thousands of times higher than the magnetic permeability of the air gap.

[0036]

[Effects of the Invention] As explained above, according to the present invention,
The length (L) of the parallel part of the base of the convex tapered part is set to the maximum length S when the separation distance S and separation distance T are equal, so that the stroke of the plunger is a predetermined length. The magnetic attraction force changes uniformly in the range before and after, and there is no shortage of attraction force in the intermediate region of the advance stroke of the plunger, making it possible to obtain good characteristics.

Therefore, within the above conditions, the length (L) of the parallel portion is determined based on ensuring the drainage function of the water pushed out from the concave portion during latching and ensuring the magnetic attraction force when the plunger retreats. In this way, a latching solenoid with no fear of latching errors can be constructed, and the solenoid can be adapted to a longer stroke or to a smaller size.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the relationship between a plunger and a pole core of a latching solenoid according to the present invention.

FIG. 2 is a semi-longitudinal view of a latching solenoid according to the invention.

FIG. 3 shows the relationship between the plunger and the pole core according to the advanced position of the plunger according to the present invention; (A) when the plunger is retracted, and (B) when the plunger stroke (S) is the distance between the tapered parts ( (C) is a diagram showing when S is smaller than T.

FIG. 4 is a comparison characteristic diagram of the suction force of a latching solenoid.

FIG. 5 is a comparison characteristic diagram of the suction force of a long-stroke latching solenoid.

[Figure 6] Shows a magnetic circuit model of a latching solenoid, (A) is its equivalent electric circuit diagram, (B) is an equivalent electric circuit diagram for attraction force analysis, and (C) is the correspondence between circuit elements. FIG.

[Explanation of symbols]

1... Pole core 1a... Latch part 1b... Convex tapered part 2... Coil 3... Case 4... Plunger 4a... Contact part 4b... Parallel part 4c... Concave tapered part 5... Yoke 6... Magnet L... Length S of parallel part ...Separation distance between the latch part of the pole core and the contact part of the plunger

Claims (1)

[Claims] [Claim 1] A pole core (
1), and a plunger (4) is slidably disposed inside the case (3), and the plunger is moved by the magnetic attraction force of the coil (2) disposed outside the case (3). (4) moves forward and backward with respect to the pole core (1),
Also, a part of each opposing surface between the pole core (1) and the plunger (4) is formed by the plunger (
A latch part (1a) and an abutting part (4a) form a plane perpendicular to the sliding axis of 4) and abut each other in a latching state, and the center of the latch part (1a) and the abutting part (4a) In a latching solenoid, the convex taper part (4c) of the latching solenoid has a concave taper part (1b) having a concave conical surface on one side and a convex taper part (4c) having a convex conical surface on the other side. The base forms a parallel part (4b) consisting of a cylindrical surface parallel to the sliding axis, and the length (L) of this parallel part (4b) is the same as that between the latch part (1a) of the pole core (1) and the plunger (4). Separation distance between the contact part (4a) (
S) is a convex taper part (4c) and a concave taper part (1b)
A latching solenoid characterized in that the maximum length of the separation distance is set equal to the separation distance (T) between the latching solenoid and the latching solenoid.