JPS58202696A - Mc type pickup cartridge - Google Patents

Abstract

PURPOSE:To improve the converting efficiency and at the same time to reduce the weight of an MC type cartridge, by setting a coil so that the coil axis is parallel to the shaft of a cantilever within a gap between magnets which are set so that the same poles of these magnets are set opposite to each other with a minute gap and that the magnetic axes of the magnets are parallel to the shaft of the cantilever. CONSTITUTION:A disk-shaped coil holder 4 made of a nonmagnetic matter such as synthetic resin, etc. is fixed at the base end of a cantilever 1 having a reproducing stylus at its tip to form an oscillating system. This oscillating system is supported freely rockingly at a supporting part 9 by means of a cylindrical damper 7 and a suspension wire 8. The holder 4 contains coil holes at each oscillating direction position of 45-45 stereos provided at the outer circumference of the holder 4. Then left and right channel coils 2 and 3 turned round with thin belt-shaped conductors in the form of a layer are put into the coil holes and fixed there. Then two cylindrical magnets 5 are set for each channel so that their same poles ae set opposite to each other with a minute gap, and the coils 2 and 3 are set within the gap with coincidence between the center axis of the magnet and the coil axis.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a moving coil type pickup cartridge (hereinafter referred to as MC cartridge), and its characteristics are that the same poles face each other with a minute gap and the magnetic axis is By arranging the coil in a minute gap between the magnets, which are parallel to the cantilever axis, the coil axis is parallel to the cantilever axis.
The advantage is that the conversion efficiency can be increased and the weight of the magnetic circuit can be significantly reduced.

Conventionally, an MC cartridge having a cross-sectional shape as shown in FIG. 1 has been known.

That is, a vibration system consisting of a coil holder 4 that supports left and right channel coils 2 and 3 fixed to the base end of a cantilever 1 as shown in FIG. 2 is connected to a permanent magnet as shown in FIG. 50 facing a magnetic circuit with yokes 6 provided at both ends.

However, in such a device, the magnetic flux density within the magnetic gap is suppressed to the saturation magnetic flux density of the yoke and cannot be increased any higher, and the magnetic flux density near the lower end of the magnetic gap becomes low. As a result, the conversion efficiency of the pickup was poor, and the magnetic circuit was large and heavy, making it impossible to make the MC cartridge lighter.

An object of the present invention is to improve the drawbacks of the conventional device described above, and to obtain a lightweight MC cartridge with high conversion efficiency.

An embodiment of the present invention will be described with reference to FIGS. 4 to 6.

FIG. 4 is a cross-sectional view of the vibration system, in which a disk-shaped coil holder 4 made of a non-magnetic material such as synthetic resin is fixed to the base end of a cantilever 1 having a regenerating needle at the tip. 7 and the suspension wire 8, it is swingably supported by a support portion 9.

As shown in FIG. 5, the coil holder 4 is provided with coil holes at each vibration direction position of the 45-45 stereo on its outer periphery, and each coil hole is provided with a thin strip (with a width of 0.5 mm).
Coils 2 and 3 for the left and right channels, which are formed by winding conductors (1 to 02 mm) in layers, are inserted and fixed.

Figure 6 shows the magnetic circuit, @f
'v y 36 /l/ S''''L VC2Q (D
/J. 3 is placed so that the center axis of the magnet and the coil axis are aligned.

As shown by the dotted line in the figure, the magnetic flux distribution within this minute gap moves from the center of the coil to the periphery (in the opposite direction when the polarity is reversed), and the vibration of the needle tip causes the coil to move forward and backward ( An electromotive force is generated when the robot moves in the left-right direction (in the figure).

FIG. 7 shows another embodiment of the magnetic circuit,
Instead of having two cylindrical magnets for each channel,
Arc-shaped flat magnets are placed opposite each other and used in common for both channels.

The magnetic flux distribution in the vicinity of the coil is almost orthogonal to the cantilever axis, and is divided into upper and lower parts from the center of the coil toward the periphery of the coil.

As explained above, the MC cartridge of the present invention is
A coil is placed within the small gap between two magnets, which are placed so that the same poles face each other with a small gap and the magnetic axis is parallel to the cantilever axis. By arranging them, the conversion efficiency can be significantly increased, and the weight of the cartridge can also be reduced by making the magnetic circuit lighter.

[Brief explanation of drawings]

Fig. 1: Longitudinal cross-sectional view of a conventionally known MC cartridge Fig. 2: A perspective view of its vibration system Fig. 3: A perspective view of its magnetic circuit Fig. 4: An embodiment of the present invention Fig. 5 is a vertical cross-sectional view of the MC cartridge of 2008.A perspective view of its vibration system is Fig. 6.A perspective view of its magnetic circuit is 2 and 3... Coil 4 for left and right channels, coil holder 5, magnet agent, patent attorney Makoto Oka - 5-

Claims (1)

[Claims] The coil is supported on a non-magnetic coil holder fixed to the base end of the cantilever so that the coil axis is parallel to the cantilever center axis, with the same poles facing each other with a small gap, and the magnetic axis is parallel to the cantilever axis F. A moving coil type pickup cartridge, characterized in that the coil is disposed within the minute gap between magnets that are arranged parallel to each other.