JP2000277338A - Noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize fixing by a method, wherein a case is engaged with a lid by the use of a noise filter case of an insulating resin. SOLUTION: Polybutyleneterephthalate is used as a molding material for a noise filter case. As other materials, polyporpylene, or the like substantially equivalent in an insulating property, heat-resistance, and mechanical strength may be used. Furthermore, if mechanical strength is required for increasing, a filler, or the like is filled into the molding material for mechanical reinforcing. A case 2 and lid 1 are each obtained by injection molding. In particular, the lid 1 has a fixing part 3. The top end of the fixing part 3 of the lid 1 has a shape projecting to the left and the right, and the top end projecting left and right is set R-chamfered or C-chamfered, and has a shape of being easy to insert, when the lid 1 is inserted into the case part 2. Furthermore, the left and right projection dimensions of the fixing part 3 are of such extent, that after a toroidal core 5 is inserted into the case part 2 and the lid 1 is inserted into the case part 2, the lid 1 does not slip out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise filter used for measures against conduction noise of various electronic devices.

[0002]

2. Description of the Related Art As a component for absorbing noise flowing through an electric wire, there is known a technology of winding a toroidal ferrite core or the like to absorb the noise flowing through the electric wire. As a method of performing insulation treatment on the toroidal core in such a noise suppression component, a method of accommodating the toroidal core in a case made of epoxy resin coating or insulating resin is known.

[0003] However, in the case of a noise component using a toroidal core, it is often necessary to protect the impact of the toroidal core, and a method of storing the noise component in a case molded with an insulating resin that emphasizes the protection of the toroidal core is generally used. It has become a target.

A noise filter case is composed of a case portion and a lid portion. A method of inserting a toroidal core into the case portion and fixing the lid portion with an adhesive, or, as shown in FIG. The part 7 was provided and fixed. The case part 8 and the lid part 7 are provided with a lid part fixing part 9 and a case part fixing part 10, both of which form a fixing part by simultaneous molding.

The lid 7 is provided with a fixing portion 9, which is tapered from the tip of the fixing portion 9. The case part 8
Has a tapered receiving portion provided on the fixing portion 9 of the lid portion 7. The case portion 8 includes a toroidal core 5
Is inserted, and the cover 7 is pushed into the case 8 to be fixed.

[0006]

However, as shown in FIG. 3, the structure in which the fixed portion of the case portion 8 and the lid portion 7 is formed by injection molding has a structure in which both the case portion 8 and the lid portion 7 have a molding dimension. Accuracy is required, and poor dimensional accuracy results in incomplete fixing. In order to solve this problem, the fixing is incomplete unless the taper at the projection of the lid fixing portion 9 is increased.

In addition, a mold structure for molding the lid 7 having the above structure cannot be formed unless a slide type is adopted, which causes problems in the cost of the mold and the life of the mold.

[0008] That is, an object of the present invention is to provide a noise filter case in which fixing parts are provided on both the case part and the lid part and can be fixed without using a mold having a slide structure.

[0009]

According to the present invention, as shown in FIG. 1, a noise filter case is made up of a case portion 2 and a lid portion 1 using an insulating resin. The cover 1 is provided with a cover fixing portion 3 and a case fixing portion 4.
The lid 1 is provided with a projection for the lid fixing portion 3, and the tip of the projection has a shape projecting right and left, and the case 2 is provided with a projection for the lid fixing portion 3 of the lid 1. Equipped with a receiving part,
By providing the cover fixing portion 3 and the case fixing portion 4 for fixing the case portion 2 and the cover portion 1, the fixing accuracy is improved, and the mold can be made inexpensive.

[0010]

Next, embodiments of the present invention will be described in detail with reference to examples.

FIG. 1 is a front view of a noise filter case according to the present invention. As the toroidal core 5, a ferrite core for suppressing conduction noise is generally used. The material of the ferrite used for the toroidal core 5 is a manganese / zinc-based material having high magnetic permeability.

Polybutylene terephthalate (PBT) was used as a molding material for the noise filter case. Other materials such as polypropylene (PP) may be used as long as they have substantially the same insulation, heat resistance, and mechanical strength. If it is necessary to increase the mechanical strength, the molding material can be reinforced by adding a filler or the like.

The case 2 and the lid 1 are each obtained by injection molding. In particular, the lid 1 has a fixing portion 3, but such a shape is not necessary for a sliding die, as shown in FIG. It can be molded. The case portion 2 can be formed in one direction in a vertical direction by a conventional mold structure.

The tip of the fixing portion 3 of the lid 1 has a shape projecting right and left. The tip projecting right and left is R-shaped or C-shaped, and the lid 1 is inserted into the case 2. At this time, it is necessary to make the shape easy to insert. Also,
After the toroidal core 5 is inserted into the case portion 2 and the lid portion 1 is inserted into the case portion 2, the left and right overhanging dimensions of the fixing portion 3 are such that they do not come off easily.

[0015]

As described above, according to the present invention,
The case for the noise filter is formed of a case part and a lid part by using an insulating resin as a molding material, a fixing part is provided on the case part and the lid part, a projection part is provided on the fixing part of the lid part, and a tip of the projection part is formed. A noise filter case that is fixed and stable can be obtained by making a shape that protrudes left and right and a receiving portion for the fixing portion of the lid portion in the case portion, and inserting and fixing the lid portion in the case portion. Also, a noise filter case that can be molded without using a special mold such as a slide mold was obtained.

[Brief description of the drawings]

FIG. 1 is an exploded view of a noise filter according to the present invention.

FIG. 2 is a sectional view of a mold for a lid according to the present invention.

FIG. 3 is an exploded view of a conventional noise filter.

[Explanation of Symbols] 1 lid part 2 case part 3 lid part fixing part 4 case part fixing part 5 toroidal core 6 lid part die 7 lid part 8 case part 9 lid part fixing part 10 case part fixing part

Claims (2)

[Claims] 1. A noise filter in which a toroidal core is housed in a noise filter case, and an electric wire is wound around the noise filter case, wherein an insulating resin is used for the noise filter case, and a case portion and a lid portion are provided. A noise filter characterized by fitting with 2. The noise filter case according to claim 1, wherein the case portion and the cover portion have a shape in which a fixing protrusion is provided on the cover portion, and a tip of the protrusion protrudes left and right. A noise filter comprising: the case portion provided with a receiving portion for the projection; and a fixing portion for fixing the case portion and the lid.