JPS592439B2 - Electromagnetic pick-up - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic pickup, and more particularly to a so-called in-person magnet pickup.

Generally, in this type of pickup, a magnetically conductive material fixed to a cantilever is located in or near a pole piece of a yoke around which a coil is wound, and this magnetically conductive material is excited by a magnet placed nearby. Wow, it's like that.

That is, as shown schematically in FIG. 3, the cantilever 1 is made to vibrate around a fulcrum P, and the magnet 3 is designed to induce magnetic flux into a magnetically conductive material 2 fixed to the cantilever 1. .

Therefore, in this type of device, as the cantilever 1 vibrates, the distance between the magnetically conductive material 2 and the magnet 3 changes, so the magnetic flux induced in the magnetically conductive material 2 also changes, resulting in cross-modulation distortion. It has the disadvantage that it occurs frequently.

The purpose of the present invention is to prevent the above-mentioned cross-modulation distortion from occurring;
It is an object of the present invention to provide an electromagnetic pickup cartridge that generates a high voltage and has a simple structure.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic perspective view of the first embodiment, which is characterized in that the vibration fulcrum of the cantilever is set in the gap of an H-shaped quadrupole magnetized magnet.

That is, in the figure, 1 is a cantilever, to the tip of which a stylus 1a is fixed, and to the rear thereof is fixed a so-called μ pipe 2 made of a highly magnetically conductive material.

Reference numeral 4 denotes a magnet having a substantially H-shape with gaps 4a and 4b, and magnetic poles are formed at each of the four corners, and the magnetic poles are arranged so that poles of the same sex face each other through the gaps 4a and 4b. It has become.

Reference numeral 5 denotes a cylindrical damper made of an elastic material such as butyl rubber for supporting the cantilever 1 in a freely vibrating manner, into which the magnetically permeable material 2 of the cantilever 1 is inserted.

The damper 5 is fixed to the pickup main body by known means, but in the present invention, the damper 5 is fixed at the center of the gap 4a in the H-shaped magnet 4.

6 is a substantially U-shaped yoke around which coils 7 and 7 are wound and a pole piece portion 9 is formed.

The magnetically permeable material 2 of the cantilever 1 is located in or near this pole piece portion 9.

Therefore, when the magnetically conductive material 2 is vibrated by sliding the stylus 1a over the sound groove of a record, the magnetically conductive material 2 vibrates with the center of the damper 5 as the vibration fulcrum, and the magnetically conductive material 2 excited by the magnet 4 vibrates. The change in magnetic flux at the pole piece 9 can be extracted as an electrical signal by the coil 7.7 wound around the yoke 6.

FIG. 2 is a schematic perspective view of the second embodiment, in which the damper 5 into which 201 parts of the magnetically permeable material of the cantilever 1 is inserted is placed in the center of the gap 4a of the H-shaped magnet 4, as in the first embodiment. It is fixed.

8 is a magnetically conductive plate magnetically connected to the magnetically conductive material 2, and four magnetically conductive pieces 8a, 8b, 8 are arranged at an angle of 90 degrees to each other.
c, 8a are provided.

6a and 6b are yokes around which coils 7a and 7b are wound, respectively; the end of the yoke 6a faces the magnetically conductive piece 8a18b, and the end of the yoke 6b faces the magnetically conductive pieces 8a and 8b.

The magnetically conductive pieces 8 at8b, 8c, and 8d are excited by the magnet 4 through the magnetically conductive material 2, and the vibration of the cantilever 1 can be extracted as a stereo signal to the coils 7a and 7b.

Note that the magnetically conductive plate 8 does not necessarily include four magnetically conductive pieces 8at8b.
, 8c, and 8a are not necessary and may be disk-shaped, and it goes without saying that the magnetically conductive plate 8 is not in contact with the magnet 4.

According to the embodiment above, the vibration fulcrum P of the cantilever 1 supported by the damper 5 is excited over a wide range with a constant magnetic field in the gap 4a formed between poles of the same sex in the magnet 4. As shown in FIG. 4, since the magnetic flux induced in the magnetically permeable material 2 by the vibration of the cantilever 1 does not change even when the position changes, cross-modulation distortion can be significantly reduced, and changes in sound quality due to stylus pressure can be reduced.

In addition, since it is excited by two poles of the same sex, the output voltage is larger than that of one pole. Therefore, the magnetic conductive material 2 can be made smaller and lighter than conventional ones to achieve high compliance, or In order to reduce the induction of external noise, it is also possible to reduce the number of turns of the coil and obtain the same output voltage as the conventional one.

Furthermore, in terms of structure, only one magnet 4 magnetized with four poles can be used, so there is no increase in the number of parts, and since it is one integrated magnet, there is no need to get used to variations in the distance between the poles. Therefore, there is a remarkable effect that pickups with uniform performance can be manufactured in large quantities.

As shown above, according to the present invention, it is possible to obtain a high-output industo magnetic type pickup with a simple configuration, which has low intermodulation distortion and little change in sound quality due to stylus pressure.

In the above embodiment, the magnet 4 is H-shaped, but the present invention is not limited to this.In short, the vibration fulcrum P of the cantilever 1 may be held between the same poles in the gap of one magnet magnetized with four poles. Of course, it is sufficient to make it so that it can be done, and various design changes can be made.

Furthermore, the magnetically permeable material 2 in the embodiments is not necessarily limited to a magnetically permeable material, and it goes without saying that a hard magnetic material may be used if necessary within the scope of the claims of the present invention.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of the present invention;
The figure is a schematic perspective view showing the second embodiment, FIG. 3 is an explanatory diagram for explaining the principle of a conventional intuitive magnetic pickup, and FIG. 4 is an illustration of the state of the vibration system in the present invention. FIG. 1...Cantilever, 1a...Stylus, 2...Magnetic conductive material, 4...Magnet,
4a, 4b...Gap, 5...Damper, 6, 6a, 6b...Yoke, 7.7a, 7
b... Coil, 8... Magnetic conductive plate, 9.
...Pole piece, P...Vibration fulcrum.

Claims (1)

[Claims] 1. In an electromagnetic pickup in which the rear end of a magnetically conductive material fixed to the rear of a cantilever equipped with a stylus is positioned in or near the pole piece of a yoke around which a coil is wound, the cantilever is The vibration fulcrum of the fixed magnetic conductive material is
An electromagnetic pickup characterized in that the cantilever is supported in a gap formed between poles of the same sex in two magnets.