JPS5952595B2 - Manufacturing method of stereo pickup cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a stereo pickup cartridge, and it is possible to easily manufacture a stereo pickup cartridge with good magnetic efficiency and at low cost.

The pickup cartridge is made by cutting a plate made of high magnetic permeability material into a suitable shape to form a pole piece assembly, winding a coil around this pole piece assembly, and installing a magnet in the center that vibrates in conjunction with the vibration of the stylus. It is formed by arranging I.

For this reason, the coil must be wound around the pole piece assembly, which is made of a material with high magnetic permeability.

Since this coil requires winding a very thin wire many times, the pole piece assembly must above all have a shape and structure that makes it easy to wind the coil.

Therefore, winding has been conventionally performed using various methods.

The conventional method will be explained with reference to FIGS. 1 and 2.

First, in the device shown in FIG. 1, a magnetic plate (a plate made of a high magnetic permeability material, hereinafter referred to as a magnetic plate) 1 is formed into a U-shape, and two coils 2 are wound around opposite locations in the center of the magnetic plate 1. The tips are formed into pole pieces la and lb.

The pole pieces la and lb are used by bending the magnetic plate 1 by 135 degrees, manufacturing two similar pole pieces, and arranging them so that their tips form a square shape.

In a pickup cartridge having such a shape, the coil 2 cannot actually be wound around the magnetic plate 1 bent into the shape shown in the figure, so the magnetic plate 1 is manufactured separately into a U-shaped one and a T-shaped one, and the coil 2 will be joined (overlaid) inside the bobbin 3 wound with.

Therefore, there is a problem that the number of parts increases and the number of manufacturing steps also increases.

In the structure shown in FIG. 2, a magnetic plate 1 is cut into a substantially C-shape and laminated, and a coil 2 is wound around one side of the magnetic plate 1.

In this case, both ends will be the pole pieces 1a and lb, so two identical ones are manufactured and placed at an angle of 90°, and a groove 2a (not shown) is provided at the base. The pole pieces are combined so that they are facing each other and used.

In order to wind the coil 2 in a pickup car I-ridge having such a shape, a winding machine with a complicated structure is required, which has a part that holds the wire of the coil 2 in its mouth and rotates between the pole pieces la and lb. Therefore, there is a problem that the equipment is expensive and inefficient, resulting in high costs.

The present invention provides a method for manufacturing a stereo pickup cartridge that solves these problems.

An embodiment of the present invention will be explained with reference to FIGS. 3 to 7. In FIG. 3, 1 is a plate made of a high magnetic permeability material;
That is, it is a magnetic plate that is cut into rod shapes.

Coils 2 are wound on both sides of the midpoint of this magnetic plate 1.

After winding the coil 2, the vicinity of the center part is bent 90 degrees in the same direction and made to face each other to form a pole piece assembly.

Prepare two identical magnetic plates 1, and combine these two magnetic plates 1 at right angles after bending them by 90 degrees as described above, so that the pole pieces la, lb, IC, and ld form four opposing sides. (See Figure 3).

Note that the coils 2 are connected in series between opposing pole pieces.

Pole piece holders 4 and 5 are fitted into the open end (left end in the figure) and the joint end (right end in the figure) of the pole piece assembly shaped as shown in FIG.

The pole piece holder 4.5 has a shape as shown in FIG.

That is, the pole piece holder 4 is provided with pole heath insertion holes 4a, 4b, 4C, and 4d (4d is not shown because it becomes the back of 4b),
It is designed to insert a, lb, IC, and ld.

Therefore, these pole piece insertion holes 4a, 4b, 4C,
4 (H: Insert the pole heaths la, lb, IC, and ld, respectively.

The pole piece holder 5 has a hole 5a as shown in FIG.
, 5b, the joint end of the pole piece assembly is fitted into the hole 5a, and the protrusion 6a of the printed circuit board 6 is inserted and fitted into the hole 5b.

Note that a rectangular yoke block 7 made of a high magnetic permeability material may be placed at the joint end of the pole piece assembly in order to compensate for deterioration caused by bending the magnetic plate 1.

8 in FIG. 6 is a shield case.

This shield case 8 has a cylindrical shape with a small diameter end, and is made of a magnetic material.

When the pole piece holder 4, the pole piece assembly, the pole piece holder 5, and the printed circuit board 6 that have been assembled into one body are housed in the shield case 8, the result will be as shown in FIG.

Polpy in this state, 7. la, lb, IC
, 1d (7), and the entire stereo car 1-rig is completed by placing the stylus assembly (not shown) between them and housing the entire thing in a case (not shown).

In the embodiments described above, the pole piece assembly is formed from two magnetic plates, but it can also be made from one magnetic plate.

FIG. 8 shows this.

In this figure, 1 is a magnetic plate, and the square central part 1
Four pieces are cut outward from each side of e in a shape that projects at an angle of 90 degrees to each other, and the coil 2 is wound around each piece.

The coil 2 has opposing pole pieces connected in series.

Next, the central part 1e of the magnetic plate 1 with the coil 2 wound thereon is placed in a jig 9 as shown in FIG. (upward in the figure).

At this time, a rectangular yoke block 7 made of a high magnetic permeability material may be placed above the central portion 1e serving as the joining end in order to compensate for deterioration caused by bending the magnetic plate 1.

By doing this, a pole piece assembly having a shape as shown in FIG. 10 can be obtained.

After that, manufacturing is carried out in the same manner as in the previous embodiment.

In addition, in the above examples, Paul P Xla, lb,
Although the IC, 1d (7) has a bent shape so that the tip is inside the part around which the coil 2 is wound, it may be in a straight shape instead of this.

Since the present invention is constructed as described above, it has the advantage that a stereo pickup cartridge with good magnetic efficiency can be manufactured easily and at low cost.

Furthermore, by making the pole piece sufficiently long and thin, the coil winding diameter (width dimension) can be kept small compared to the number of turns of the coil, so there is an advantage that the assembly type and weight can be reduced.

[Brief explanation of the drawing]

1 and 2 are perspective views showing a conventional example, FIG. 3 is a front view showing the first step of an embodiment of the present invention, and FIG. 4 shows a bent state of the one in FIG. A side view, Fig. 5 is a perspective view of the two pieces shown in Fig. 4 combined, Fig. 6 is a cross-sectional view showing the state in which the pole piece holder is attached to the one shown in Fig. 5, and Fig. 7 is the one shown in Fig. 6. FIG. 8 is a front view showing the first step of another embodiment of the present invention, and FIG. 9 is a perspective view showing the device shown in FIG. 8 fitted in a jig. , FIG. 10 is a perspective view showing the state of the device shown in FIG. 8 after processing. 1...magnetic plate, la, lb, IC, l
d...Pole piece, 2...Coil,
4, 5...Pole piece holder, 7...
...Yoke block, 8...Shield case,
9...Jig.

Claims (1)

[Claims]] A pole piece assembly is formed by winding a coil on both sides of the midpoint of a plate made of a high magnetic permeability material, and then bending the central part by 90 degrees in the same direction so as to face each other. A pole piece assembly is formed on four sides with open ends facing each other, a pole piece holder is fitted to the open end and the joint end of the pole piece assembly, and the whole is held in a shield case made of a high magnetic permeability material. A method of manufacturing a stereo pickup cartridge, characterized by: 2. To form four sides with the open ends of the pole piece assembly facing each other, two plates made of high magnetic conductivity material were prepared, and the two plates were bent at 90 degrees and then assembled at right angles. A method for manufacturing a stereo pickup cartridge according to claim 1, characterized in that: 3. In order to form the four sides with the open ends of the pole piece assembly facing each other, a plate made of a high magnetic conductivity material was cut into a cross shape, and each piece cut into the cross shape was bent by 90 degrees. A method for manufacturing a stereo pickup cartridge according to claim 1.