JPH03212911A - Fixed iron core assembly for solenoid and its manufacturing method - Google Patents

Abstract

PURPOSE:To improve solenoid characteristics by fitting and fixing a fixed core inside a tubular part formed integrally in a yoke and by providing an exposed non-magnetic member to an edge surface side of the fixed core between the tubular part and the fixed core. CONSTITUTION:A fixed core 30 is formed in advance in another process to a cylindrical shape and a fitted and fixed shading coil 40 is prepared in a relieving part at the side of an edge surface 31. The fixed core 30 is made to be supplied to a specified position inside a press die for forming a yoke 20. A long magnetic steel plate 20 is put inside the press die which enables multi-stage processing processes successively. A small hole is formed at a position A, a tubular part 23 is formed at a position B, the fixed core 30 is put by pressure inside a through-hole which is limited by a tubular part 23 at a position C, an edge part of the fixed core 30 is caulked or an edge part is formed at a position D, and both edges of a steel plate are bent to form a U-shape generally at a position E; thereby, a yoke 20 is completed. Magnetic efficiency and solenoid characteristics can be improved in this way.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a fixed core assembly for a solenoid, and more specifically, to an assembly of a yoke and a fixed core that surround a coil that forms the magnetic circuit of a solenoid. The present invention relates to a fixed core assembly in which a non-magnetic member is fixed to the end face of a three-dimensional fixed core, and a method for manufacturing the same.

(B) Prior Art Generally, it is well known that a magnetic saturation phenomenon exists in a magnetic circuit (hereinafter referred to as a magnetic path) due to the characteristics of the materials constituting it. Therefore, in a solenoid, the maximum magnetic flux density is usually set in a state where the magnetic flux of the magnetic path is not saturated and the maximum magnetic flux density is set upward (usually based on the cross-sectional area of the movable iron core).

If the cross-sectional area of a part of the magnetic path becomes insufficient in such a state, saturation of the magnetic flux occurs, leakage magnetic flux increases, and the magnetic properties rapidly deteriorate. This means that by modifying such components to minimize leakage flux, the magnetic properties can be significantly improved.

On the other hand, if there is a connection in the magnetic path, its magnetic resistance follows Ohm's law for magnetic circuits. If we consider only the connection part now, its magnetic resistance Q will be Q -t/μ·S.

Here, l is the gap length of tangent ms S is the contact area of the connection part μ is the magnetic permeability in air It is.

The magnetic resistance of the gap is 10G to 200 times higher than that of the iron part under the same conditions (when the gap is filled with iron).
Therefore, if a connection part is absolutely necessary in the magnetic path due to the structure, it is essential to minimize the gap and increase the contact area.

Conventionally, as a method of integrally fixing a fixed iron core to a yoke that surrounds the coil and forms a magnetic path with seven rollers, there is a method as shown in ■ Japanese Utility Model Publication No. 58-37111 and shown in Fig. 7. A method of fitting the small diameter part of the fixed iron core to the large part of the yoke and caulking it, or
As shown in the above publication and shown in FIG. 8, a method is known in which a fixed core is formed integrally with a yoke by press working.

However, in the case of ■ above, the following i) and iJ)
There are problems like this.

l) The area of contact between fixed core a and yoke b cannot be made large.

The reason for this is that if the diameter of the main part of the fixed core is D, the diameter of the small diameter part that fits into the large part of the yoke is d1, and the thickness of the yoke is t, then the area S of the contact part is S = π (D "-d")
/ 4 + x d t Since there is a small gap in the contact area due to plating or fitting, we want to make the area large, but D is the movable iron core C of the solenoid.
The maximum value D can take is limited by the size of the solenoid, etc.

lj) A constricted portion occurs in the magnetic circuit, making it difficult to efficiently pass the magnetic flux from the yoke to the fixed core.

This is because, as is clear from Fig. 9, the magnetic fluxes flow parallel to each other in the peripheral part e of the yoke (near the part surrounding the coil and the part continuous to that part), but the magnetic flux flows in parallel to each other at the base of the fixed core (near the root). The minimum cross-sectional area of the circle r shown by the broken line in Figure 9 (the minimum cross-sectional area near the root is a circle with the same diameter as the diameter of the movable core, centered on the axis of the fixed core and above the yoke). , the area on the virtual circumferential surface determined by considering the flow of magnetic flux)
When the diameter of the large diameter part of the fixed core is the same as the diameter of the movable core, Ss is constricted as Ss=πD and the magnetic flux concentrates there, making it impossible for the magnetic flux to pass efficiently.

Furthermore, the same can be said for the structure (2) above as in (M) above.

To solve this problem, conventional solenoids either increase the wall thickness of the entire end portion of the yoke or
As shown in Figure 0, a magnetic washer (f) is brought into contact with the end portion to provide magnetic reinforcement.

However, in any of the above cases, a small diameter part is formed in the fixed core and the small diameter part is fitted to the large side of the yoke, which results in a narrowing of the magnetic flux distribution area, making it difficult to efficiently pass the magnetic flux from the yoke to the fixed core. I can't. Moreover, in the former case, the fixed iron core not only does not improve the unbalance of magnetic flux density between the root and other parts of the yoke, but also increases the overall weight due to the use of extra iron material. If there is a size restriction, increasing the thickness of the plate will put pressure on the coil winding area, which in turn will put pressure on the performance of the solenoid itself. The thickness of the commercially available steel plate is 1.2 mm, 1
．． This is because the use of thick steel plates is restricted from the processing point of view because the steel plates (6 mm, 2.0 ma+, 2.3 mm, 2.6 mm, or 3°2 mm) are formed into a U-shape by bending. The latter case also has the disadvantage that the washer must be molded separately.

Furthermore, in conventional fixed core assemblies, the yoke and the fixed core are manufactured in separate processes and assembled in an assembly process completely separate from the yoke manufacturing process, resulting in high manufacturing costs.

On the other hand, when fixing a non-magnetic member such as a shade coil or a magnetic shielding member to the end face of the fixed core, the shade coil has an annular shape on the end face of the fixed core, as shown in Fig. 11. l! After forming the shading coil h and inserting the shading coil h into the annular groove, the open end of the annular groove is caulked at several places to prevent the shading coil from coming out. As shown in the figure, after fitting the magnetic shielding member kJ or m into the hole i or j formed on the end face of the fixed core, the end face of the fixed core or the end of the magnetic shielding member is caulked or press-fitted into the hole. Or it is fixed by adhesive.

However, in the former case, there are problems such as damage to the shading coil due to caulking, damage to the shading coil due to localized stress concentration after long-term use, or loosening of the crimping.

On the other hand, in the case of joints, the diameter of the part embedded in the fixed core is increased for strength reasons, in order to receive the impact force when the movable core collides with the shielding member when it is attracted.
If this happens, the effective cross-sectional area of the magnetic path of the fixed core will be reduced, and there is a limit to how much strength can be increased.

(C) Problems to be Solved by the Invention The problems to be solved by the present invention are related to a fixed core assembly in which a non-magnetic member is fixed to the end face and a method for manufacturing the same.
By integrally forming the tubular part on the yoke by press working, and by fitting and fixing the large diameter part into the tubular part without forming a small diameter part on the fixed iron core, the contact area between the yoke and the fixed iron core can be reduced compared to conventional products. In addition to making it larger in comparison, the purpose of having a fixed iron core is to secure the minimum cross-sectional area of the root as much as necessary, and also to be able to hold the non-magnetic member stably and reliably.

(d) Means for solving the problem One invention of the present application is to integrally fix a fixed core to a magnetic yoke forming a part of a magnetic circuit, and fix a non-magnetic member to the end face of the fixed core. In the fixed iron core assembly for a solenoid, the fixed iron core is attached to the yoke by integrally forming a tubular part extending in the axial direction protruding from one surface of the yoke, and installing the fixed iron core in the tubular part. A fixed iron core is fitted and fixed, and the non-magnetic member is provided between the tubular portion and the fixed iron core so as to be exposed on the end face side of the fixed iron core.

Another invention of the present application is a fixed iron core assembly for a solenoid, which includes a fixed iron core integrally fixed to a magnetic yoke forming a part of a magnetic circuit, and a non-magnetic member fixed to the end face of the fixed iron core. In the manufacturing method, a fixed iron core made of a plate-shaped yoke material is attached by forming a small hole in the part, and by press working, a tubular part extending in the axial direction around the small hole is made to protrude from one side of the yoke. The fixed core is integrally formed, a small diameter part is formed on the outer periphery of the end of the fixed core, the annular non-magnetic member is fitted into the small diameter part, and the fixed core is inserted into a through hole defined by the tubular part. It is configured so that it is press-fitted and fixed.

Still another invention of the present application is a fixed iron core assembly for a solenoid, in which a fixed iron core is integrally fixed to a magnetic yoke forming a part of a magnetic circuit, and a non-magnetic member is fixed to the end face of the fixed iron core. In the manufacturing method, a fixed iron core of a plate-shaped yoke material is attached by forming a small hole in the part, and by press working, a tubular part extending in the axial direction centering on the small hole is protruded from one side of the yoke. and a convex portion inside the tip of the tubular portion, and a non-magnetic member having a size approximately the same as the outer diameter of the fixed core between the convex portion and the end face of the fixed core. The fixed iron core is press-fitted and fixed into a through hole defined by the tubular portion with the fixed iron core interposed therebetween.

(E) Function The fixed core assembly for a solenoid having the above configuration is assembled with the coil and the movable core to the solenoid by a known method.

In the fixed iron core assembly of the present invention, the contact area between the yoke and the fixed iron core can be reduced by 1.5 to 2 mm compared to that of a conventional solenoid without using a particularly thick material for the yoke.
．． In addition, with a fixed iron core, the required cross-sectional area of the magnetic path at the root can be secured without using thick material, improving the characteristics of the solenoid. is possible. In addition, the non-magnetic member can be fixed stably and reliably without being damaged, and the life of the solenoid can be extended.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, a solenoid 1 made using a fixed core assembly 10 according to an embodiment of the present invention having a shaded coil as a non-magnetic member is shown. In the same figure, 2
0 is a U-shaped yoke that surrounds the coil and forms a magnetic path.
30 is fitted and fixed in the insertion hole of the yoke I; fixed iron core;
2 is a coil, 3 is a movable iron core, and 4 is a plate-shaped yoke fitted to the other end of the yoke 20.

The yoke 20 has a U-shape or a U-shape, and has an intermediate wall 21 to which a fixed iron core is attached, and two end walls 22 that are continuous with the intermediate wall 21 and parallel to each other.

A tubular portion 23 protruding toward the coil is formed approximately at the center of the intermediate wall, and a through hole 24 for inserting a fixed iron core is formed inside the tubular portion. A small projection 27 is formed at the end of the tubular portion 23 on the side of the movable core, as shown in Figure 8g2, which projects inward in the radial direction. This protrusion has a function of preventing the shade removal coil from falling off, which will be described later. A cylindrical fixed core 30 is fitted and fixed within the through hole 24. A second cutout portion 32 is formed on the outer periphery of the end face 31 of the fixed core 30 on the movable core 3 side, and a non-magnetic shaded coil 40 is fitted and fixed to the second cutout portion.

Therefore, the bear coil 40 is exposed to the end surface 31 and placed between the tubular portion 23 and the small diameter portion of the fixed core defined by the second cut portion.

Yoke 20 is manufactured as follows. That is, in FIG. 3, the fixed core 30 is formed into a cylindrical shape in advance in a separate process, and a contour filler 40 is provided at the second recessed portion on the end face 31 side.
are prepared in a fitted and fixed state so that the fixed core can be supplied to a predetermined position in a press mold for forming the yoke 20. Then, a long magnetic steel plate 20' is placed in a press mold that can perform a multi-step processing process sequentially, and a small hole n is formed in the steel plate at position A, and then a tubular part 2 is formed at position B.
3, press-fit the fixed core 30 into the through hole defined by the tubular part 23 at position RC, caulk the end of the fixed core or form an end surface at position E, and bend both ends of the steel plate at position E. The whole is formed into a U-shape, thereby completing the yoke 20.

In this series of operations, the steel plate is formed by sequentially moving one press die within the press each time one press process is completed.

The contact area S1 of the yoke in this embodiment is defined as the height h from the rear end surface 26 of the yoke 20 to the tip (upper end in FIG. 1) of the tubular portion (h is usually 1.5 of the plate thickness t of the yoke). ), the diameter of the fixed core is 3, and the width of the second cut is W, then S H-yr D l (h - w ). In reality, a relatively small curved surface r is formed at the opening of the through hole by press molding, and this creates an annular gap yfI between the fixed iron and the fixed iron. It can be filled in by pressing it into place and caulking it.

The minimum cross-sectional area of the root is Ss, and the minimum cross-sectional area of the root of the conventional product is Ss=πD.
t Here, because of the relationship D0+2r2)D, Ss+>
It becomes Ss.

In FIG. 4, a fixed core assembly 10a according to another embodiment of the present invention is shown. In this embodiment, a conical inner surface 271 is formed at the open end of the through hole 24a on the rear end surface 26a side,
The fixed iron core 30a also has a conical outer surface 3 in contact with its inclined inner surface.
11 is formed.

This conical inner surface 27a is formed simultaneously with the press working of the tubular portion 23a, and the conical outer surface 31 of the fixed iron core 30a! may be formed by caulking a part of the fixed core when the fixed core is press-fitted into the through hole, or may be formed during machining of the fixed core.

The contact area S2 of this example is as follows, and the root minimum cross-sectional area Ss is 5s2-rD4t. These S2 and Ss2 can also be made larger than S and Ss, respectively.

The following table shows a comparison between the actual products of the above two embodiments and the conventional fixed core assembly with dimensions as shown in FIG. 4.

Conventional product Example 1 Example 2 Movable core and fixed core 201mm" 201mm
"201mm" cross-sectional area (diameter part) 232mm of yoke and fixed core 373mm
'402mm'' contact area Fixed core with minimum root cross-sectional area 140II+m2 201mm'' 201mm2 In FIG. 6, a fixed core assembly 10b according to yet another embodiment of the present invention is shown. In this embodiment, a tubular portion 23b is formed in a plate-shaped yoke 20b corresponding to the magnetic plate 4 of the solenoid shown in FIGS. 1 and 4, and an end face 31. This is an example in which a plate-shaped magnetic shielding plate 50 is fixed as a non-magnetic member in contact with b. When manufacturing the fixed core assembly 10b of this embodiment, an annular convex portion 27b protruding radially inward at the tip (upper end in FIG. 6) of the tubular portion 23b is formed at the same time as the tubular portion is formed. On the other hand, fixed core 30
A magnetic shielding plate 50 is prepared in advance in a state in which it is adhered to the end surface 31b of b. Then, in the process of forming the yoke 20b, the fixed iron core 30 is
b is press-fitted into the through hole 24b.

Further, the magnetic shielding plate 50 is fixed by forming a small protrusion protruding in the radial direction on the end of the tubular portion 23b on the movable core side and adhering the magnetic shielding plate. It is also possible to press-fit the fixed core 30b into the through hole 24b.

Note that although the calculation formula for the above embodiment has been omitted, the calculation formula may be set up by following the calculation formula for the embodiment shown in FIG. Further, in the embodiments shown in FIGS. 1 and 4, a tubular portion may be formed on the magnetic plate 4 side as in this embodiment.

(G) Effects According to the present invention, the following effects can be achieved.

■The contact area between the yoke and the fixed core as well as the minimum cross-sectional area of the root can be increased and the gap can be reduced, so the magnetic field of the fixed core assembly can be improved without increasing the number of parts or thickening the plate. Efficiency can be significantly improved compared to conventional products.

■It is possible to fix the stationary iron core to the yoke in a pressing mold for the plate material of the yoke.

■If the fixed iron core is press-fitted into the through hole of the yoke, it is possible to minimize the gap.

■By uniformly tightening the entire circumference of non-magnetic members such as dark circles and magnetic shielding members, it is possible to fix them to the fixed core with force, and it is possible to improve durability.

■Damage to the darkening coil due to caulking is eliminated.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a solenoid using a fixed core assembly according to an embodiment of the present invention, FIG. 2 is an enlarged view of a part of FIG. 1,
Fig. 3 is a diagram showing the manufacturing process of the yoke of the fixed core assembly of Fig. 1, Fig. 4 is a sectional view of a solenoid using the fixed core assembly of another embodiment, and Fig. 5 is a conventional product and this implementation. Figure 6 is a sectional view of a solenoid using a fixed core assembly of another embodiment, and Figures 7 to 12 are diagrams showing the dimensions of each part for comparison with the example. FIG. 3 is a diagram showing a fixed core assembly. 10.1. Oa, 10b: Fixed core assembly 20.20
a, 20b: Yoke 23.23a, 23b: Tubular portion 24.24a, 24b: Through hole 30.30, 30b: Fixed core 40: Shading coil 50: Magnetic shielding member No. 1 Conventional product No. 5 Example 1 DWDMW ' / 6mm T 113.2 mm HLL 1RLL 1RNM DW 5 MRH DOS DM M' 16 PNM T = 3.2mm 4-10.2 RNM HM 2RNQ IH " / 3.2mm D2 = 'IO 4rnm H〆cod 12rnm Do -Dm-116mm t = 3.2mm H=7mm Yes 10.2mm D+-〆/ 3.2 mm D211〆lO,4rnm D, g!116mm p4-g20rnH No 2mm W - 12mm [C] Fig. 11 Fig. 11 Concave drawing Fig.

Claims (3)

[Claims] 1. In a fixed iron core assembly for a solenoid in which a fixed iron core is integrally fixed to a magnetic yoke that forms part of a magnetic circuit, and a non-magnetic member is fixed to the end face of the fixed iron core, the fixed iron core is attached to the yoke. A tubular part extending in the axial direction projects from one surface of the yoke and is integrally formed in the attachment part of the yoke, the fixed core is fitted and fixed within the tubular part, and the fixed core is fixed between the tubular part and the fixed core. A fixed iron core assembly for a solenoid, characterized in that the non-magnetic member is exposed and provided on an end face side of the fixed iron core. 2. In a method of manufacturing a fixed iron core assembly for a solenoid, a fixed iron core is integrally fixed to a magnetic yoke that forms part of a magnetic circuit, and a non-magnetic member is fixed to the end face of the fixed iron core. A small hole is formed in the attachment part of the fixed iron core of the yoke material, and a tubular part extending in the axial direction centering on the small hole is integrally formed by pressing from one surface of the yoke, and the fixed core is fixed. A small diameter part is formed on the outer periphery of the end of the iron core, and the annular non-magnetic member is fitted into the small diameter part,
A method of manufacturing a fixed core assembly for a solenoid, comprising press-fitting and fixing the fixed core into a through hole defined by the tubular portion. 3. In a method of manufacturing a fixed iron core assembly for a solenoid, a fixed iron core is integrally fixed to a magnetic yoke that forms part of a magnetic circuit, and a non-magnetic member is fixed to the end face of the fixed iron core. A small hole is formed in the attachment part of the fixed iron core of the yoke material, and a tubular part extending in the axial direction centering on the small hole is integrally formed by protruding from one surface of the yoke by press working. A convex portion is formed inside the tip of the portion, and a non-magnetic member having a size approximately the same as the outer diameter of the fixed core is interposed between the convex portion and the end face of the fixed core so as to be limited by the tubular portion. A method for manufacturing a fixed core assembly for a solenoid, comprising press-fitting and fixing the fixed core into a through hole.