JPS6022713Y2 - Pickup Cartridge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup cartridge, and particularly to improvements in a moving magnet type pickup.

In the conventional moving magnet type cartridge, for example, as shown in Fig. 1, a pyramidal prism-shaped magnet 3 is installed at the base of a cantilever 1 having a stylus 2 at the tip, and changes in the magnetic field due to the vibration of the magnet are guided to a yoke 4 and wound around the yoke. Output is obtained from the rotated coil 5.

These characteristics are that because the yoke 4 is inside the coil 5, the magnetic permeability changes depending on the strength of the magnetic field, causing distortion, and when the frequency increases, eddy currents occur in the yoke, causing high frequency There have been rumors that the output decreases, and because the coil is wound around the yoke, the output impedance increases, and the reproduction characteristics change due to the influence of the load impedance.

On the other hand, in a moving coil type pickup, the coil is vibrated, so the above problem does not occur, but since the coil is wound around the vibration system, it is difficult to manufacture, the equivalent mass increases, and it is necessary to replace the regeneration needle etc. However, it has the disadvantage that it is not easy to use.

Furthermore, as shown in Japanese Unexamined Patent Publication No. 720-720, a bar-shaped magnet is provided in an inverted V shape when viewed from the front on the stylus mounting surface of the cantilever, and the bar-shaped magnet is magnetized in the longitudinal direction to form a pot-shaped yoke. A coil is shown in which a wound coil is inserted into the rod-shaped magnet to convert the vibration of the cantilever into vertical vibration of the rod-shaped magnet, thereby inducing a voltage in the coil.

However, in the moving magnet type pickup cartridge with this configuration, the magnetic flux cuts the coil and generates electricity only when the magnet, which is magnetized to N-5 in the longitudinal direction of the rod-shaped magnet, vibrates in the vertical (up and down) direction within the pot-shaped core. If the magnet is tilted, it will not generate electricity.For this reason, if the magnet is placed at the vibration fulcrum of the vibration system (the center position of the armature such as a magnet), there will be no vertical (up and down) component, so the configuration described above will not generate electricity. If a magnet, which does not generate electricity unless it is moved closer to the needle tip than the vibration fulcrum, is moved to the needle tip, the equivalent mass of the vibration system increases in proportion to the square of the distance from the vibration fulcrum.

It is also generally known that the cantilever of a cartridge causes split vibration in the high range.For example, in the low range, the rubber of the damper is used as a suspension to rotate and vibrate, but in the high range, where the mass of the cantilever becomes a problem. The power generation system, including the magnet, resonates vertically (up and down) and deviates more than the angle change of the cantilever, resulting in a large resonance peak.

At this time, resonance occurs in a specific direction regardless of the direction of vibration caused by the record groove, and this is due to the non-uniformity of the mass of the damper and cantilever.

In this way, not only a power generation component due to angular deviation but also a vertical component is generated, and this vertical component appears in the high frequency range, and the left or right signal crosstalks with the right or left signal in the high frequency range, resulting in crosstalk characteristics. It has drawbacks that make it worse.

The present invention was developed in view of the above drawbacks, and eliminates the drawbacks of the moving coil type pickup and has the characteristics of the moving fill type pickup. To provide a moving magnet type pickup cartridge capable of imparting change to a coil.

The feature of this invention is that a coil is provided near the magnet fitted to the end of the cantilever, and the armature of the magnet moves around the coil, and the flux from the armature changes directly in the coil and is cut off, inducing an electromotive force. It is in the pickup cartridge that was made to look like this.

An embodiment of the present invention will be described in detail below with reference to FIGS. 2 to 4.

Figures 2a, b, and c are route maps showing one embodiment of the moving magnet type pickup cartridge of the present invention.
Figure a is a perspective view of the vibrating part of the present invention, Figure 2 is a sectional view taken along line B-B in Figure 2C, and Figure 2C is a cross-sectional view taken along line CC in Figure 2a; A vibration system consisting of a stylus 2 at the tip of the cantilever 1 and a plate-shaped magnet 3 at the other end is attached to one end of the cantilever in order to connect it to a fixed part 8 with a tension wire 7 via a damper 6. The tension wire 7 is fixed, the other end is inserted into the center hole of the fixed part, the tension wire is stretched, and the damping of the damper is adjusted while the tension wire is fixed with a screw.

Furthermore, a ring-shaped winding frame 9 that surrounds the circumference of the plate-shaped circular magnet is disposed with a predetermined gap between the plate-shaped circular magnet and the ring-shaped winding frame 9.

Although not shown in FIGS. 2C, the winding frame is fixed to a casing 11, etc., which will be described later.

The winding frame is provided with O-shaped air core coils 10a, 10b, 10c, l centered on the 45°-45° direction from the plane where the cantilever 1 is viewed from the front and the stylus is cut in half in the longitudinal direction.
ed is located.

A stereo signal is obtained by connecting the coils 10a, 10b and 10c, 10d facing each other in the 45° direction in series in opposite directions.

A casing 11 is arranged to surround the winding frame 9 and the fixing part 8.

The principle of power generation in the above-described configuration of the present invention will be explained with reference to FIG.

As shown in Figure 3, fixed coils 10a and 10b are arranged so as to cut off the leakage magnetic flux from the N pole to the S pole of the magnet 3, which is magnetized in the thickness direction in the same direction as the axial direction of the cantilever 1.
, 10c, and 10d are arranged so that when the magnet 3 is in its neutral position, the center axis of the magnet coincides with the radial direction of the coil, so that no amplitude change is applied to the stylus attached to the tip of the cantilever 1. When the magnet changes from the state shown in FIG. 3a or FIG. 3C, the coil 10av arranged near the magnet
10c or 10t), N of magnet 3 passing through 10d
Since the leakage magnetic flux from the pole to the S pole changes and the amount of magnetic flux cut by the coil changes, an electromotive force corresponding to the inclination of the magnet 3 is generated in the coil.

That is, no electromotive force is generated in Fig. 3, and Fig. 3 a and C are respectively generated.
The opposite occurs, creating a push-pull effect.

Of course, the case where the magnetic flux from the moving magnet 3 cuts the coil is exactly the same as the case where the moving coil cuts the magnetic flux.In a moving coil type pickup, the coil itself moves, so the number of turns is limited because it needs to be miniaturized. However, this proposal is advantageous because it is not subject to this point restriction.

By surrounding the entire coil with a soft magnetic casing 11 which also serves as a shield, magnetic flux can be applied to the coil more effectively without scattering.

FIG. 4 shows another embodiment of the moving magnet type pickup cartridge of the present invention, in which the winding frame 9 is approximately U-shaped, and the U-shaped portion is provided with coil winding portion recesses 9a and 9b. Coils 10e and 10 are inserted into the recess in an O-shape when viewed from the front.
f is wound in an X shape, and the vibration system including the magnet is inserted from the bottom of the casing 11 and the winding frame 9. With this configuration, when the vibration system (stylus, cantilever, and magnet) is removed from the pickup body, It can be pulled downwards very easily.

Since the present invention is constructed as described above, it is easy to replace the vibration system including the stylus 2, and since it is a moving magnet system and does not include a magnetic core, there is no increase in output impedance and distortion due to the magnetic characteristics of the magnetic core can be reduced. It can have the same features as the moving coil type, and since it does not vibrate in the vertical direction, no vertical component is induced in the electromotive force, which has the effect of reducing high-frequency crosstalk.

[Brief explanation of the drawing]

Fig. 1 is a route diagram of a conventional moving magnet type pickup, Fig. 2 a is a perspective view showing an embodiment of the moving magnet type pickup of the present invention, and Fig. 2 is a sectional view taken along line B-B in Fig. 2C. , FIG. 2C is a sectional view taken along the line C-C in FIG. 2a, FIG. 1...Cantilever, 2...Stylus, 3...Amateur, 9...Reel frame,
10a-10f... Coil.

Claims (1)

[Scope of utility model registration request] It has a cantilever with a stylus at one end and a disc-shaped magnet at the other end, and the magnet is magnetized in the thickness direction in the same direction as the axial direction of the cantilever, and the magnet has an N pole magnetized to an S pole. It has a fixed coil arranged so as to cut leakage magnetic flux toward the pole, and the coil is arranged so that its center axis coincides with the radial direction of the magnet at the neutral position of the magnet, and the coil moves in the coiler according to the inclination of the magnet. A pickup cartridge that generates an electromotive force.