JP2000023283A - Voice coil bobbin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive voice coil bobbin which has high roundness and also can be automatically and easily produced by a machine. SOLUTION: A strip-shaped bobbin member 2 is formed into a cylindrical shape, and a 1st automorphic tape piece 4A is pasted on the outer circumference of the member 2 in a half round or more so that a butted line 3 of the members 2 is set at its center to secure the spaces at both edges of the piece 4A. Furthermore, a 2nd automorphic tape piece 4B is pasted between both edges of the piece 4A. The butted lines 7A and 7B set between both pieces 4A and 4B are shifted by 120 degrees from the line 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bobbin used for a voice coil of a speaker.

[0002]

2. Description of the Related Art A conventional general bobbin for a voice coil is shown in FIG. The bobbin 1 for voice coil is formed by forming a strip-shaped bobbin material 2 made of paper or the like into a cylindrical shape, and attaching a shape-retaining tape piece 4 to the outer periphery thereof so that the joint 3 of the bobbin material 2 is not opened. is there. As shown in FIG. 3B, the shape-retaining tape piece 4 is attached so that the coil winding portion P remains on one end side of the cylindrical bobbin material 2 in the axial direction.
The voice coil bobbin 1 has a coil 5 as shown in FIG.
Is wound to form a voice coil for the speaker.

However, the voice coil bobbin of the type shown in FIG. 3 has a problem that the bobbin material 2 is easily deformed into a tapered shape with the joint 3 of the bobbin 2 as a vertex.

As an improvement on this point, a bobbin for a voice coil as shown in FIG. 5 or FIG. 6 is also known. These bobbins 1 have a roundness increased by covering a paper tube 6 on the outer periphery of a bobbin material 2 formed into a cylindrical shape. As the paper tube 6, a paper tape wound in a spiral shape and stuck together is used. In particular, in the case of the bobbin 1 for a voice coil shown in FIG. 6, the buttocks 3 of the bobbin material 2 are slanted to reduce a change in strength in the circumferential direction. It is known that the structure in which the bobbin material 2 is held in a cylindrical shape by the paper tube 6 increases the strength of the voice coil bobbin 1 and improves the sound quality.

[0005]

However, a bobbin for a voice coil using a paper tube involves inserting a cylindrical bobbin material into the paper tube and uniformly bonding the bobbin material and the paper tube. Due to the necessity, it is difficult to perform this operation using a machine, and it has been difficult to automate manufacturing. For this reason, there has been a problem that the cost of a bobbin for a voice coil using a paper tube increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a voice coil bobbin which can achieve high roundness and can be easily manufactured by a machine.

[0007]

In order to achieve this object, a bobbin for a voice coil according to the present invention is formed by forming a strip-shaped bobbin material into a cylindrical shape, and attaching a first shape-retaining tape piece to the outer periphery of the bobbin. At least half the circumference with the joint of the material in the center, attached so that there is a gap between both side edges, and further, a second shape retaining tape piece is attached between both side edges of the first shape retaining tape piece. Things.

[0008] In particular, in the voice coil bobbin according to the present invention, the joint between the first shape-retaining tape piece and the second shape-retaining tape piece is circumferentially different from the bobbin material's joint.
It is preferable to adopt a configuration that is shifted by °.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. This voice coil bobbin 1 is formed by forming a strip-shaped bobbin material 2 into a cylindrical shape, and wrapping a first shape-retaining tape piece 4A on the outer periphery of the bobbin material 2/3 with the joint 3 of the bobbin material at the center.
The second shape-retaining tape piece 4B is attached so as to cover the circumference and further to cover the remaining one-third circumference. As a result, the joints 7A and 7B of the first shape retaining tape piece 4A and the second shape retaining tape piece 4B are shifted from the joint 3 of the bobbin material 2 in the circumferential direction by 120 °.

With such a structure, the entire periphery of the cylindrical bobbin material 2 is reinforced by the shape-retaining tape pieces 4A and 4B, and the joint 3 of the bobbin material 2 and the shape-retaining tape pieces 4A and 4B are abutted. Eyes 7A and 7B are circumferentially 120 °
Since the positions are shifted from one another, the balance of rigidity in the circumferential direction is improved, and the same roundness as a voice coil bobbin using a paper tube can be obtained.

A bobbin 1 for a voice coil having this structure.
Can be manufactured by simply attaching the first shape-retaining tape piece 4A and the second shape-retaining tape piece 4B from the outside in a state where the bobbin material 2 is wound around a mandrel and formed into a cylindrical shape. Is easy, and the production can be automated.

In the bobbin for a voice coil of the present invention, the joints 7A and 7B of the first shape-retaining tape piece 4A and the second shape-retaining tape piece 4B correspond to the joints 3 of the bobbin material 2.
Is preferably 120 ° in the circumferential direction, but this shift may not be exactly 120 ° but may be close to 120 °.

FIG. 2 shows a preferred example of a voice coil using the voice coil bobbin 1 of FIG. In this voice coil, two copper thin pieces 8A and 8B are stuck on the second shape retaining tape piece 4B of the bobbin 1 in FIG. 1 at intervals in the circumferential direction, and both ends of the coil 5 wound on the bobbin material 2 are provided. Leader 5
A and 5B are placed on the copper flakes 8A and 8B, and a holding tape piece 10 having holes 9A and 9B is attached to positions corresponding to the copper flakes 8A and 8B from above. The lead wires 5A and 5B and the copper flakes 8A and 8B are soldered in the holes 9A and 9B. A tinsel wire (not shown) is connected to the soldered portion by soldering.

[0014]

As described above, according to the present invention, it is possible to provide a low cost voice coil bobbin which has a high roundness and can be easily manufactured automatically by a machine.

[Brief description of the drawings]

1A and 1B show one embodiment of a voice coil bobbin according to the present invention, wherein FIG. 1A is a plan view, FIG. 1B is a front view, and FIG.
Is a bottom view.

2A is a partially cutaway front view showing a voice coil using the bobbin of FIG. 1, and FIG. 2B is a bottom view.

FIG. 3 shows an example of a conventional bobbin for a voice coil.
(A) is a plan view, (b) is a front view.

FIG. 4 is a plan view showing a voice coil using the bobbin of FIG. 3;

5A and 5B show another example of a conventional bobbin for a voice coil, wherein FIG. 5A is a plan view and FIG. 5B is a front view.

6 (a) is a plan view and FIG. 6 (b) is a front view showing still another example of the conventional voice coil bobbin.

[Explanation of symbols]

1: bobbin for voice coil 2: bobbin material 3: butt joint of bobbin material 2 4A: first shape-retaining tape piece 4B: second shape-retaining tape piece 5: coil 7A, 7B: first shape-retaining tape piece Butt joint between 4A and second shape retaining tape piece 4B

Claims (2)

[Claims] 1. A strip-shaped bobbin material (2) is formed into a cylindrical shape, and a first shape-retaining tape piece (4A) is formed on the outer periphery of the bobbin material (2A) at least half the circumference with the bobbin material joint (3) at the center. A bobbin for a voice coil, wherein the bobbin is attached so that the edges are spaced apart, and further a second shape retaining tape piece (4B) is attached between both side edges of the first shape retaining tape piece (4A). 2. The joint (7A, 7B) between the first shape-retaining tape piece (4A) and the second shape-retaining tape piece (4B) is
2. The bobbin for a voice coil according to claim 1, wherein the bobbin is shifted 120 degrees in a circumferential direction from a joint (3) of the bobbin material.