JPH07297024A - Coil bobbin - Google Patents

Abstract

PURPOSE:To ensure larger winding space for a coil easily. CONSTITUTION:In a coil bobbin 2, whose parts 2a to be wound a coil are mounted on the periphery of a core 1 with a rectangular section, notch parts 1d are respectively provided in the corner parts with a rectangular section of the core 1 and at the same time, the parts 2a are formed of a molded material, with which the notch parts 1d provided in the core 1 are filled by co- molding, so that gaps S exist between the coil 3 and the core 1 when the coil 3 is wound on the parts 2a. Accordingly, as the wall thickness of the core 1 for ensuring the flow properties of a molding material at the time of a co- molding work with the core 1 can be formed of the components of the notch parts 1d, the gaps S between the coil 3 and the core 1 are made small in the extent that a breakdown voltage can be ensured when the coil 3 is wound on the molded material and it is made possible to ensure larger winding space for the coil 3 easily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coil bobbin used in an electromagnet device such as an electromagnetic relay.

[0002]

2. Description of the Related Art Conventionally, there is a coil bobbin of this type shown in FIG. This coil bobbin is formed by simultaneous molding using a molding material such as synthetic resin so that the coil-wound portion A covers the periphery of the iron core B having a square cross section with a predetermined wall thickness. Then, the coil C is wound.

When an electric current is applied to the coil C, the magnetic flux generated magnetizes the iron core B to become an electromagnet, and the magnetic attraction force attracts a movable member (not shown) to bring the contacts into contact. Part (not shown) is driven to open and close,
It becomes an electromagnetic relay.

[0004]

In the conventional coil bobbin described above, the wall thickness of the coil wound portion A which is formed simultaneously by covering the periphery of the iron core B ensures the flowability of the forming material. Because it cannot be made too thin. For example, polybutylene terephthalate (P
In the case of BT), the wall thickness is limited to about 0.3 mm. Therefore, the coil winding space around the coil wound portion A is reduced by the thickness of the coil winding portion A, which becomes a factor of weakening the magnetomotive force of the coil. In particular, for coil bobbins used in thinning electromagnetic relays, coil winding part A
If the thickness is too large, the coil space may not be secured, which may cause a serious problem.

As a countermeasure against this, the coil wound portion A is
There is one that is formed by applying an insulating coating of polyimide resin etc. on the entire surface of the iron core B. In this case, since the wall thickness is not required as much as the molding process, a large coil winding space can be secured, Since the suction surface of the movable member is also coated, the suction holding force decreases due to the increase in magnetic resistance. Therefore, when masking and coating the suction surface, the work is troublesome and expensive.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coil bobbin which can easily secure a larger coil winding space.

[0007]

In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided a coil bobbin in which a coil wound portion is mounted around an iron core having a polygonal cross section. Is provided at a corner portion having a polygonal cross section, and the coil wound portion has a cutout portion of the iron core so that a gap is formed between the coil and the iron core when the coil is wound. It is formed by a molded body to be buried.

According to a second aspect of the present invention, in the first aspect, the notch portion is formed in a concave shape.

According to a third aspect of the present invention, in the first aspect, the molded body has a corner portion formed in a flat or rounded shape along the coil winding direction. .

[0010]

According to the first aspect of the present invention, since the molded body forming the coil-wound portion fills the notch provided in the corner portion of the iron core having a polygonal cross section, the iron core is formed. Since the thickness for securing the flowability of the molding material during simultaneous molding with can be formed by the notch, the gap between the coil and the iron core when the coil is wound around the molded body Can be made smaller within a range where the withstand voltage can be ensured, and more coil winding space can be easily ensured.

According to the second aspect of the present invention, since the cutout portion of the iron core is formed in a concave shape, the molded body filling the cutout portion has a thickness which is concave as compared with a flat shape. Can be thickened.

According to the third aspect of the present invention, the molded body forming the coil-wound portion is wound because the corner portion is flat or rounded along the coil winding direction. The coil will not be damaged by the angular portion.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

Reference numeral 1 denotes an iron core, which is made of a magnetic material such as electromagnetic soft iron and has a rectangular cross section and an elongated central portion 1a and both end portions thereof.
1b and 1c are formed in a U shape, and the central portion 1a is provided with notches 1d formed by notching a triangular portion at four corners of a rectangular cross section.

A coil bobbin 2 is made of a molding material such as a synthetic resin, and the coil wound portion 2a and the brim portions 2b and 2c are mounted on the iron core 1 as a molded body by means of simultaneous molding.

More specifically, the coil-wound portion 2a is formed in a triangular shape in cross section so as to fill the notches 1d provided in the respective corners of the iron core 1, and as shown in FIG. There is a gap S between the notches so that the withstand voltage can maintain a specified value.
It is formed one size larger than the triangular portion, which has a cutout cross-sectional shape of 1d. At this time, the wall thickness h of the molded body of the coil-wound portion 2a, that is, the height of the triangular section shown in FIG. 3 is, for example, in the case of polybutylene terephthalate (PBT), which is a commonly used molding material, iron It is about 0.3 mm, which is the minimum required dimension to secure the flowability of the molding material when co-molding with the core 1.

Further, the collar portions 2b, 2c are both end portions 1b, 1c of the iron core 1.
Are provided on both ends of the coil wound portion 2a by abutting on the outside. That is, the coil-wound portion 2a is formed by a molded body in which the cutouts 1d of the iron core 1 are filled, whereby the collar portion is formed.
This means that 2b and 2c are connected.

As described above, the coil bobbin 2 formed integrally with the iron core 1 is magnetized by the magnetic flux generated when a current is applied to the coil 3 and becomes an electromagnet. As a result, the movable member (not shown) is attracted to the end faces of both ends 1b and 1c, which are the magnetic pole faces of the iron core 1, and the contact part (not shown) is driven to open and close to become an electromagnetic relay. .

In the coil bobbin 2 as described above, the molded body forming the coil wound portion 2a is the iron core.
Since the notch 1d provided at each corner of the rectangular cross section of 1 is filled, the wall thickness h for securing the flowability of the molding material when co-molding with the iron core 1 is the notch 1d. Therefore, when the coil 3 is wound around the molded body, the gap S between the coil 3 and the iron core 1 is reduced to the extent that the withstand voltage can be secured, so that the iron core 1 is insulated. It is possible to easily secure a larger winding space for the coil 3 without using a troublesome means such as coating, and it is possible to increase the magnetomotive force of the coil 3.

In the present embodiment, the cutout 1d is
By cutting out the triangular portion at the corner, the surface after being cut out is flat as shown in FIG. 3, but as shown in FIGS. 4 (a) and 4 (c), it has a square shape. The notched surface may be formed into a right-angled concave shape by notching the portion, or the notch may be formed by notching the fan-shaped portion as shown in FIGS. The surface after being carved may be formed in an arcuate concave shape.

In these cases, the molded body in which the cutout portion 1d is filled becomes thicker in thickness h by the concave shape than the flat shape, in other words, if there is a margin for the withstand voltage. By reducing the gap S to secure it, more winding space for the coil 3 can be secured, and if the wall thickness h to secure the flowability of the molding material has a margin, The corner portion of the molded body forming the coil wound portion 2a is shown in FIG. 4 (c) along the coil winding direction.
The coil 3 is formed in a flat shape as shown in FIG. 2 or in a round shape as shown in FIG.
It becomes difficult to be damaged because it is not wound around the angular portion as shown in.

Further, in the present embodiment, the iron core 1 has a rectangular cross section, but it is not limited to this and may be a polygon having a corner portion forming the notch 1d.

[0023]

According to the first aspect of the present invention, the molded body forming the coil-wound portion fills the notch provided in the corner portion of the iron core having a polygonal cross section. Since the thickness for securing the flowability of the molding material during simultaneous molding with can be formed by the notch, the gap between the coil and the iron core when the coil is wound around the molded body By making the withstand voltage small within a range where the withstand voltage can be secured, it is possible to easily secure a larger coil winding space.

According to the second aspect, in addition to the effect of the first aspect, the cutout portion of the iron core is formed in a concave shape, so that the molded body filling the cutout portion has a flat wall thickness. It can be made thicker by the amount of the concave shape than the rectangular shape. In other words, if there is a margin for the withstand voltage, the gap for securing it can be made smaller, so that more coil winding space can be secured. it can.

According to the third aspect, in addition to the effect of the first aspect, the molded body forming the coil wound portion has a corner portion which is flat along the coil winding direction or The rounded shape prevents the wound coil from being damaged by the angular portion.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view of the same.

FIG. 3 is a cross-sectional view of an essential part of the above.

FIG. 4 is a sectional view of another main part of the above.

FIG. 5 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Iron core 1d Notch 2 Coil bobbin 2a Coil wound part (molded body) 3 Coil S gap

Claims (3)

[Claims] 1. A coil bobbin in which a coil wound portion is mounted around an iron core having a polygonal cross section, wherein a notch is provided in a corner portion of the iron core having a polygonal cross section, and the coil wound portion is provided. The coil bobbin is formed by a molded body that fills the notch portion of the iron core so that there is a gap between the coil and the iron core when the coil is wound. 2. The coil bobbin according to claim 1, wherein the cutout portion is formed in a concave shape. 3. The coil bobbin according to claim 1, wherein the molded body has a corner portion formed in a flat shape or a rounded shape along a coil winding direction.