JPH10231946A - Linear solenoid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear solenoid with which an increase in the electromagnetic attracting force and small-sized construction are established compatibly. SOLUTION: A boss part 16a of a movable iron core 16 is caulked fast to the center of a leaf spring 18 made of a magnetic substance, and the periphery of the leaf spring 18 is caulked fast to the edge of a yoke 12. Thereby the magnetic circuit between the yoke 12 and movable core 16 is made parallel configuration consisting of the first magnetic circuit following the yoke 12, a side gas forming part 17, air gap, and the core 16 and the second magnetic circuit following the yoke 12, a magnetic leaf spring 18, and the core 16. Even in the region where the current flowing to the coil 15 is comparatively small (low current region), the magnetic flux flows through the second magnetic circuit on the leaf spring 18 side free of air gap, and an attracting force characteristic near the linear as ideal is obtained in the low current region.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear solenoid having an improved magnetic circuit.

[0002]

2. Description of the Related Art Conventionally, a linear solenoid has been used, for example, as a drive source of a hydraulic control valve as disclosed in Japanese Patent Application Laid-Open No. 5-126275. In this device, as shown in FIG. 5, a cylindrical coil 71 resin-molded is arranged in a cylindrical yoke 70 also serving as a housing.
A cylindrical fixed iron core 72 is arranged on the inner periphery of this coil,
A shaft 74 is slidably inserted in the inner peripheral portion of the fixed iron core 72 via a bearing 73 so as to be slidable in the axial direction. One end of the shaft 74 is connected to the spool 7 of the hydraulic control valve 69.
5, a movable iron core 76 attracted to the fixed iron core 72 is fitted to the other end of the shaft 74, and the outer peripheral surface of the movable iron core 76 forms a minute gap with the inner peripheral surface of the yoke 70. Facing each other. Thereby, the yoke 70 → the movable iron core 7
A magnetic circuit is constituted by the route of 6 → fixed iron core 72 → yoke 70.

[0003]

However, in the above-described conventional configuration, the movable core 7 and the yoke 70 and the movable core
6 and the fixed iron core 72, an air gap exists between them, so that the magnetic resistance of the magnetic circuit becomes considerably large. Amount) cannot be secured, and the linear solenoid has a disadvantage of being increased in size.

In recent years, as shown in FIG. 6, in order to increase a facing area of an air gap portion between a yoke 77 and a movable iron core 78, a yoke 77 has a cylindrical shape extending on the inner peripheral side of a coil 79. A configuration has been considered in which the portion 77a is integrally formed, and the outer peripheral surface of the movable iron core 78 is opposed to the inner peripheral surface of the cylindrical portion 77a of the yoke 77 via a minute gap. In this case, a magnetic circuit is configured by a route of the yoke 77 → the cylindrical portion 77a → the movable core 78 → the fixed core 82 → the yoke 77.

However, in this configuration, in order to increase the facing area of the air gap between the yoke 77 and the movable core 78, it is necessary to increase the axial dimension of the movable core 78 and to increase the cylindrical portion 77a. It is necessary to increase the diameter of the linear solenoid in order to interpose
There is a disadvantage that the linear solenoid is enlarged.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a linear solenoid capable of achieving both low magnetic resistance (increased electromagnetic attraction) and downsizing of a magnetic circuit. Is to provide.

[0007]

In order to achieve the above object, a linear solenoid according to a first aspect of the present invention is characterized in that a magnetic leaf spring made of a magnetic material is attached to a yoke,
A movable iron core is attached to the leaf spring, and the movable iron core is supported by the leaf spring.

In this configuration, a magnetic circuit between the yoke and the movable iron core includes a magnetic circuit (hereinafter, referred to as a “first magnetic circuit”) passing through the yoke → air gap → the movable iron core, and a yoke → magnetic leaf spring. → A magnetic circuit passing through the movable iron core (hereinafter referred to as “second magnetic circuit”) is provided in parallel. In this case, the first magnetic circuit is, as in the prior art,
Although an air gap exists between the yoke and the movable iron core, the magnetic resistance is relatively large, but the magnetic leaf spring side has a second magnetic resistance.
In the magnetic circuit of (1), the yoke, the magnetic leaf spring, and the movable iron core are in contact with each other, and there is no air gap. For this reason, in a region where the current flowing through the coil is relatively small (low current region), the magnetic flux also flows through the second magnetic circuit on the magnetic leaf spring side. This makes it possible to easily increase the electromagnetic attractive force in the low current region without increasing the size of the linear solenoid itself, and to obtain an ideal linear attractive force characteristic in the low current region.

By the way, the conventional structure shown in FIG.
Since the leaf spring 80 is fixed to a shaft 81 made of a non-magnetic material, and the movable iron core 78 fitted to the shaft 81 is separated from the leaf spring 80, even if the leaf spring 80 is made of a magnetic material. No magnetic circuit is formed via the leaf spring 80, and no magnetic flux flows through the leaf spring 80.

Further, in this configuration, a space is required between the coil 79 and the movable iron core 78 for interposing the cylindrical portion 77a of the yoke 77, which causes an increase in the diameter of the linear solenoid. In order to avoid this, if the diameter of the movable core 78 is reduced to secure a space for the cylindrical portion 77a, the facing area of the air gap portion between the movable core 78 and the fixed core 82 decreases, and the magnetic force of the air gap portion decreases. The resistance increases and the electromagnetic attraction decreases.

On the other hand, in the present invention, since the second magnetic circuit on the magnetic leaf spring side exists, the magnetic flux passing through the first magnetic circuit (yoke → air gap → movable core) is reduced accordingly. I can do it. Therefore, it is not necessary to interpose a part of the yoke between the coil and the movable core, and the outer peripheral surface of the movable core is opposed to the inner peripheral surface of the resin-molded coil via a minute gap as in claim 2. You may make it do. With this configuration, the facing area of the air gap between the movable core and the fixed core can be increased without increasing the diameter of the linear solenoid, and the air gap between the movable core and the fixed core can be increased. The magnetic resistance of the portion can also be reduced.

If the leaf spring is not made of a magnetic material, a magnetic cover made of a magnetic material is attached to the opening at the side end surface of the yoke, and a gap between the magnetic cover and the movable iron core is provided. Alternatively, a magnetic spring member formed of a magnetic material may be interposed. With this configuration, the magnetic cover and the magnetic spring member play the same magnetic role as the above-described magnetic leaf spring, and the second magnetic circuit includes a yoke → a magnetic cover → a magnetic spring member → a movable core. It consists of a route. Thereby, the same operation and effect as the above-described configuration of claim 1 can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a spool valve type hydraulic control valve will be described below with reference to FIGS. First, the overall configuration of the linear solenoid 11 serving as a drive source of the spool valve type hydraulic control valve will be described with reference to FIG. A yoke 12 also serving as a housing for the linear solenoid 11 is formed in a cylindrical shape from a magnetic material, and a cylindrical fixed iron core 13 is concentrically disposed inside the yoke 12. The yoke 12 is formed integrally with the left end of the fixed iron core 13. A flange 13a in the form of a collar is crimped to the left end of the yoke 12. A coil 15 molded into a cylindrical shape with a resin 14 is fitted and mounted on the outer periphery of the fixed iron core 13. Have been.

A movable iron core 16 having a columnar block shape is provided on the right side of the inner diameter cavity of the coil 15.
The outer peripheral surface of the movable iron core 16 is opposed to the inner peripheral surface of the mold resin 14 of the coil 15 via a minute gap. A plurality of oil grooves (not shown) extending in the axial direction are formed on the inner peripheral surface of the mold resin 14.
Are formed at the same time as molding, so that the oil filled in the linear solenoid 11 can freely flow through each oil groove when the movable iron core 16 slides.

The outer peripheral surface of a portion of the outer peripheral surface of the movable iron core 16 protruding rightward from the mold resin 14 is formed with a thick annular side gap forming portion 17 integrally formed on the inner periphery of the right end of the yoke 12. Is opposed to the inner peripheral end face via a minute gap. Thereby, the yoke 12 and the movable iron core 16
A first magnetic circuit is constituted by the route of the yoke 12 → the side gap forming portion 17 → the air gap → the movable iron core 16.

A stepped cylindrical boss 16a is integrally formed at the center of the right end face of the movable iron core 16, and the boss 16a is made of an elastic magnetic material (for example, SUS420).
) Is fixed to the center of a magnetic leaf spring 18 formed by the above-described method. As shown in FIG. 2, in the leaf spring 18, a plurality of openings 18b are punched around the central portion 18a, so that the outer peripheral annular portion 18c and the central portion 18a are connected by a plurality of spring pieces 18d. It is shaped like a central part 18a
Is formed with a mounting hole 18e. And
At the time of assembly, the movable iron core 16 is inserted into the mounting hole 18e of the leaf spring 18.
In the state where the small-diameter portion of the tip of the boss portion 16a is fitted, the washer 16b made of a magnetic material is fitted to the small-diameter portion of the tip of the boss portion 16a.
(See FIG. 1), and the boss 16a of the movable iron core 16 is fixed to the center of the magnetic leaf spring 18 by caulking the small diameter portion at the tip of the boss 16a.

The outer annular portion 18c of the magnetic leaf spring 18
Represents a right edge of the yoke 12 and a non-magnetic material (for example, SUS).
304) is fixed to the right end of the yoke 12 by caulking. Thereby, between the yoke 12 and the movable core 16, the yoke 12 → a magnetic leaf spring 18 → the movable core 16
The second magnetic circuit is constituted by the path (2), and this second magnetic circuit is provided in parallel with the above-described first magnetic circuit (yoke 12 → side gap forming section 17 → air gap → movable iron core 16). .

On the other hand, a non-magnetic material (for example, SUS304) is inserted into a hole 20 formed in the center of the left side surface of the movable iron core 16.
) Is press-fitted and fixed, and this shaft 21 is slidably inserted in the hollow inside diameter of the fixed iron core 13 in the axial direction (left-right direction) via a bearing member 22, and the tip of the shaft 21 is A small amount protrudes from the fixed iron core 13 to the left.

Next, the shapes of the suction surfaces of the fixed iron core 13 and the movable iron core 16 will be described. A circular concave portion 23 is formed concentrically on the end surface of the fixed iron core 13 on the movable iron core 16 side, and an annular suction surface 24 is formed on an end surface of an annular convex portion surrounding the concave portion 23. The annular suction surface 24 is formed with the same width over the entire outer periphery of the end surface of the fixed iron core 13.

Correspondingly, a tapered suction surface 25 which can enter and exit the concave portion 23 is formed concentrically with the concave portion 23 in a portion of the movable iron core 16 on the fixed iron core 13 side. A step surface 26 is formed on the outer peripheral portion of the movable core 16 at the position of the maximum diameter of the tapered suction surface 25, and the step surface 26 faces the annular suction surface 24. The step surface 26 is formed with the same width over the entire outer peripheral portion of the movable iron core 16. Further, a non-magnetic spacer 27 formed of a non-magnetic material such as brass is fixed to an end surface of the movable iron core 16 on the fixed iron core 13 side.

In this case, the gap between the annular suction surface 24 and the step surface 26 is set to be larger than the gap between the non-magnetic spacer 27 and the bottom surface of the recess 23. As a result, the non-magnetic spacer 27 is
Of the movable iron core 16 at the maximum suction, and prevents the stepped surface 26 and the tapered suction surface 25 of the movable iron core 16 from contacting the annular suction surface 24. It also plays the role of preventing it from being held by suction.

The molding resin 14 of the coil 15 includes
A connector housing 29 is integrally formed, and the terminal 28 is insert-molded into the connector housing 29.
And the coil 15 are electrically connected.

A spool valve 30 is mounted on the left end face of the linear solenoid 11 configured as described above. Hereinafter, the configuration of the spool valve 30 will be described. The spool valve 30 is configured such that a spool 32 is slidably housed in a sleeve 31 formed into a cylindrical shape by aluminum die casting. The right end of the sleeve 31 is swaged to the left end of the yoke 12 of the linear solenoid 11, and the right end of the spool 32 is
One shaft 21 is in contact with the left end. Sleeve 31
, A drain port 34, an output port 35, an input port 36, and a feedback port 37 are formed in this order from the right.

On the other hand, first and second large diameter portions 38 and 39 are formed on the spool 32, and a small annular portion is formed between the outer peripheral surface of each of the large diameter portions 38 and 39 and the inner peripheral surface of the sleeve 31. A gap (clearance) is formed. When the spool 32 moves in the axial direction, the length of the annular gap through which the hydraulic oil supplied from the hydraulic source flows from the input port 36 to the output port 35 and the length of the annular gap from the output port 35 to the drain port 34 The ratio changes, and as a result, the output pressure of the hydraulic oil flowing out of the output port 35 changes.

On the other hand, a spring storage chamber 43 for storing a return spring 44 is formed at the left end of the sleeve 31 so as to open the left end face, and an adjusting screw 45 is screwed into the opening of the spring storage chamber 43. Thus, the left end surface opening of the spring storage chamber 43 is sealed. A return spring 44 is mounted between the adjusting screw 45 and the spool 32, and the resilient force of the return spring 44 urges the spool 32 toward the linear solenoid 11 (right side). The right end is kept in contact with the left end of the shaft 21.

In the first embodiment described above, the leaf spring 18 for urging the movable iron core 16 and the shaft 21 toward the spool valve 30 is formed of a magnetic material, and the movable iron core 16 is attached to the magnetic leaf spring 18. Therefore, the magnetic circuit between the yoke 12 and the movable iron core 16 includes a yoke 12 → a side gap forming portion 17 → an air gap → a first magnetic circuit passing through the movable iron core 16, and a yoke 12 → a magnetic leaf spring 18 → The configuration is such that the second magnetic circuit passing through the movable iron core 16 is provided in parallel. In this case, although the first magnetic circuit has an air gap between the side gap forming portion 17 of the yoke 12 and the movable iron core 16 as in the related art, the magnetic resistance is relatively large. In the second magnetic circuit on the side, since the yoke 12, the magnetic leaf spring 18 and the movable iron core 16 are in contact with each other and there is no air gap, the magnetic resistance is extremely small. For this reason, in a region where the current flowing through the coil 15 is relatively small (low current region), the magnetic flux also flows through the second magnetic circuit on the magnetic leaf spring 18 side. Accordingly, in the low current region, the magnetic flux in the path of the second magnetic circuit (yoke 12 → magnetic leaf spring 18 → movable core 16) → fixed core 16 → flange portion 13a → yoke 12 additionally flows, and the movable core Electromagnetic attraction corresponding to the amount of magnetic flux passing between the fixed iron core 16 and the fixed iron core 16 acts.

By the way, in the conventional configuration (FIGS. 5 and 6), if the diameter of the fixed iron core and the movable iron core and the axial dimension are increased to increase the facing area of the air gap portion, FIG. Thus, the electromagnetic attraction force can be increased.
However, in this case, there is a disadvantage that the size of the linear solenoid increases. In addition, the linearity (linearity) of the electromagnetic attraction characteristics in a low current region required for finely adjusting the electromagnetic attraction force is insufficient, and the control characteristics cannot be improved.

On the other hand, in the present embodiment, in the low current region, the magnetic flux is added in the second magnetic circuit on the side of the leaf spring 18 without the air gap. Can be increased. This makes it possible to easily increase the electromagnetic attractive force in the low current region without increasing the physical size of the linear solenoid 11 itself, and to obtain an ideal linear attractive force characteristic in the low current region. It is possible to achieve both improvement in characteristics and downsizing of the linear solenoid 11.

On the other hand, in the conventional configuration shown in FIG.
A space for interposing the cylindrical portion 77a of the yoke is required between the movable core 9 and the movable iron core 78, which causes an increase in the diameter of the linear solenoid. In order to avoid this, if the diameter of the movable core 78 is reduced to secure a space for the cylindrical portion 77a, the facing area of the air gap portion between the movable core 78 and the fixed core 82 decreases, and the magnetic force of the air gap portion decreases. The resistance increases and the electromagnetic attraction decreases.

On the other hand, in the present embodiment, the leaf spring 18
Since the second magnetic circuit on the side exists, the amount of magnetic flux that passes through the first magnetic circuit (the yoke 12 → the side gap forming portion 17 → the air gap → the movable iron core 16) can be reduced accordingly. Therefore, there is no need to interpose a part of the yoke 12 between the coil 15 and the movable core 16, and the outer peripheral surface of the movable core 16 is minutely attached to the inner peripheral surface of the mold resin 14 of the coil 15 as shown in FIG. They can be opposed via a gap. As a result, the facing area of the air gap between the movable iron core 16 and the fixed iron core 13 can be increased without increasing the diameter of the linear solenoid 11, and the magnetic resistance of the air gap can be reduced. This also leads to an increase in electromagnetic attraction.

On the other hand, in the second embodiment of the present invention shown in FIG. 4, the leaf spring 60 for supporting the movable iron core 16 is formed of a non-magnetic material (for example, SUS304 or the like).
The cover 61 is made of a magnetic material (for example, SUS420 or the like), and a magnetic spring member 62 such as a spring made of a magnetic material is interposed between the magnetic cover 61 and the boss portion 16a of the movable iron core 16. Cover 6
1 and the movable iron core 16 are magnetically short-circuited by a magnetic spring member 62. The method of fixing the movable iron core 16 and the leaf spring 60 and the method of fixing the leaf spring 60 and the magnetic cover 61 to the yoke 12 are the same as in the first embodiment described above. Other configurations are the same as those of the first embodiment described above, and the same reference numerals are given and the description is omitted.

In the second embodiment, the magnetic cover 61
And the magnetic spring member 62 play the same magnetic role as the magnetic leaf spring 18 of the first embodiment, and the second magnetic circuit includes the yoke 12 → the magnetic cover 61 → the magnetic spring member 62.
→ It is composed of the path of the movable iron core 16. As a result, the magnetic flux also flows through the second magnetic circuit on the side of the magnetic cover 61 having no air gap, and the same operation and effect as those of the first embodiment can be obtained.

In this case, the magnetic spring member 62 and the movable core 1
It is sufficient that the boss portion 16a of No. 6 is in magnetic contact with the boss portion 16a.
Here, the magnetic contact refers to a case where the magnetic spring member 62 is brought into contact with a magnetic washer 16b crimped to the boss portion 16a of the movable iron core 16 in addition to a case where the two are in direct contact with each other. The magnetic iron 62 and the movable iron core 16 may be magnetically short-circuited by a magnetic washer 16b.

The linear solenoid of the present invention is not limited to use as a drive source for a hydraulic control valve, but can be used as a drive source for various devices requiring fine adjustment of the axial position.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional front view of a spool valve type hydraulic control valve showing a first embodiment of the present invention.

FIG. 2 is a front view of a magnetic leaf spring.

FIG. 3 is a characteristic diagram showing a relationship between an electromagnetic attraction force and a current.

FIG. 4 is an enlarged longitudinal sectional front view of a main part showing a second embodiment of the present invention.

FIG. 5 is a vertical sectional front view of a conventional spool valve type hydraulic control valve.

FIG. 6 is a longitudinal sectional front view of a spool valve type hydraulic control valve showing another conventional example.

[Explanation of symbols]

11 Linear solenoid, 12 Yoke, 13 Fixed iron core, 13a Flange, 14 Mold resin, 15
Coil, 16: movable iron core, 16a: boss portion, 17: side gap forming portion, 18: magnetic leaf spring, 21: shaft, 23: concave portion, 24: annular suction surface, 25: taper suction surface, 26: step surface Reference numeral 27, a non-magnetic spacer, 30 a spool valve, 31 a sleeve, 32 a spool, 60 a non-magnetic leaf spring, 61 a magnetic cover, 62 a magnetic spring member.

Claims (3)

[Claims] 1. A coil is disposed inside a cylindrical yoke, a fixed core is disposed inside the coil, a movable core is opposed to an axial end face of the fixed core, and an outer peripheral surface of the movable core is provided. A magnetic leaf spring made of a magnetic material is attached to the yoke, and the movable core is attached to the leaf spring. The linear solenoid is supported by the leaf spring. 2. The linear solenoid according to claim 1, wherein an outer peripheral surface of the movable core is opposed to an inner peripheral surface of the resin-molded coil via a minute gap. 3. A coil is disposed inside a cylindrical yoke, a fixed core is disposed inside the coil, a movable core is opposed to an axial end face of the fixed core, and an outer peripheral surface of the movable core is provided. And a magnetic cover formed of a magnetic material is attached to a side end opening of the yoke, and a magnetic cover is provided between the magnetic cover and the movable core. A linear solenoid characterized by interposing a spring member formed of a magnetic material.