JPS5912078B2 - Electromagnetic cartridge - Google Patents

Description

[Detailed Description of the Invention] The present invention is a pickup car used for playing records)
This paper relates to improvements in IJ cartridges, especially electromagnetic cartridges.

In general, electromagnetic pickups are classified into three types: moving magnet type, moving coil type, and moving iron piece type.The C moving magnet type is widely popular due to its advantages such as high output and ease of assembly.
There are restrictions on reducing the equivalent mass, and since the electrical impedance is small, there remain problems such as deterioration of electrical system transmission characteristics.

The moving coil type has manufacturing difficulties such as the method of drawing out the coil and winding method, the difficulty of replacing the needle, and the need for a step-up transformer due to the small output voltage, which poses cost problems. there were.

The movable iron piece type has problems such as deterioration of the linearity of the output signal with respect to displacement of the vibrator due to magnetic saturation of the magnetic circuit, and at the same time, a decrease in output voltage.

The present invention is an improvement on the conventional electromagnetic cartridge, and its first purpose is to use a soft magnetic material for the vibrator to reduce the equivalent mass of the vibrating system and improve its characteristics. .

The second objective is to reduce electrical impedance and improve electrical system transmission characteristics.

Thirdly, the linearity of magnetic flux change with respect to needle tip displacement is improved,
The purpose is to prevent magnetostriction.

Fourth, the output voltage can be increased by reducing leakage magnetic flux and increasing conversion efficiency.

Fifth, the objective is to simplify the component parts, make the manufacturing process easier, and improve processing, assembly, and precision.

The present invention will be described in detail below with reference to figures showing examples.

FIG. 1 is a structural diagram of an electromagnetic cartridge according to the present invention, where A shows a sectional view of the magnetic circuit and B shows a front view of the main body.

FIG. 2 shows a diagram of the operating principle of the electromagnetic cartridge according to the present invention, in which A is the operating state with respect to the displacement of the vibrator when the positioning needle is displaced downward, B is the operating state when no displacement is applied, and C is the operating state when the transducer is not displaced.
represents the operating state with respect to the displacement of the vibrator when the positioning needle is displaced upward.

FIG. 3 shows the relationship between the change in the direction of magnetic flux inside each pole piece and the change in the resultant magnetic flux with respect to the displacement of the needle tip of the electromagnetic cartridge according to the present invention.

FIG. 4 shows a partially sectional perspective view of an embodiment of the electromagnetic car (IJ) according to the present invention.

First, the structure of the electromagnetic cartridge according to the present invention will be explained in detail with reference to FIG.

In Fig. 1, reference numeral 2 denotes a cantilever with a positioning needle 1 fixed to its tip, and a cylindrical vibrator 3 made of a soft magnetic material or the like having a vibration fulcrum position 4 approximately at its center end is fitted and fixed to its rear end. There is.

Placement needle 1. Cantilever 2. A vibration system comprising a vibrator 3 is inserted into a viscoelastic support 9 made of rubber, synthetic resin, or the like and having a shaft hole protruding from its center, and is placed at an appropriate position.

A permanent magnet 6 is made of a hard magnetic material, and a yoke 7a made of a soft magnetic material is provided at both end magnetic poles.

The yokes 7a and 7b are placed in pressure contact with each other, and the yokes 7a and 7b are orthogonal to the axial direction of the cantilever 2, and are placed symmetrically in the front and rear (left-right symmetric in FIG. 1A) with respect to a plane passing through the vibration fulcrum position 4.

Pole pieces 6La, 6Lb made of soft magnetic material,
Among 6Ra and 6Rb, pole pieces 6La and 6Ra
is in front of the yoke 1a, and the pole pieces 6Lb, 6
Rb is placed behind the yoke 7b, and the pole pieces 6La and 6Ra and the pole pieces 6Lb and 6Rb are placed symmetrically with respect to a vertical plane passing through the central axis of the cantilever 2.

One end of the yoke 7a, one end of each of the pole pieces 5La and 5Ra, one end of the yoke 7b, and the pole piece 6Lb.
.

Each end of 6Rb faces each other with an appropriately defined gap in between.

In addition, the other end of the yoke 7a and the pole pieces 6La, 6R
The other ends of a are adjacent to one end of the vibrator 3 on the positioning needle 1 side, and are each at an angle of 45° to the vertical plane passing through the central axis of the cantilever 2.
The other end of yoke γa and pole piece 5 in the direction of
The other end of the yoke γa and the other end of the pole piece 6Ra are arranged to face each other in the Y-Y' direction.

On the other hand, the other end of the yoke 7b and the pole pieces 5Lb, 6R
The other ends of b are adjacent to the rear end of the vibrator 3, and the aforementioned x-
The other end of the x' force direction yoke 7b and the other end of the pole piece 6Lb are connected to the other end of the Y-Y' force direction yoke 7b and the pole piece 6
The other ends of Rb are arranged opposite to each other.

8La, 8Lb. 8Ra and 8Rb are pole pieces 5L
a, 6Lb.

6 Ra t 6 Rb with each coil wound 8L
a and 8Lb, and 8Ra and 8Rb are connected to each other so as to effectively generate power in response to the displacement of the vibrator 3.

Next, the action of the electromagnetic car according to the present invention) will be explained as follows.
This will be explained in detail with reference to the drawings and FIG.

Although FIG. 2 shows the operation on the L channel side, the operation on the R channel side is exactly the same, so the L channel side will be described below.

If the needle tip is not displaced in Fig. 2B, the permanent magnet 5
From the ON pole, the DC magnetic flux φ0 returns to the S pole through the yoke 7a, the air gap, the resonator 3, the air gap, and the yoke 7b, and the yoke 7a, the air gap, the pole piece 6La, the air gap, the resonator 3, the air gap, the pole piece 6Lb, the air gap. A minute DC magnetic flux φ is flowing through the yoke 7b and returning to the S pole.

Here, the DC magnetic flux φ is set to an appropriate amount that maximizes the reversible magnetic permeability of the soft magnetic material used for the pole piece and improves the linearity of magnetic flux change.
, 7b and the magnetomotive force of the permanent magnet 5.

At this time, the downward magnetic flux φ flows through the pole piece 6La, and the upward magnetic flux φ flows through the pole piece 6Lb, so the resultant magnetic flux is: If the downward magnetic flux is positive from FIG. 6Lb magnetic flux =
φ-φ=0, and the currents generated in the connected coils 8La and 8Lb cancel each other out and no power is generated.

When the needle tip is displaced downward at point A, the vibrator 3 approaches the pole piece 6La and the yoke 7b, and the vibrator 3 approaches the pole piece 6La and the yoke 7b.
A downward magnetic flux (Φ1△Φ) flows from the N pole of the permanent magnet 5 through the yoke 7a, the air gap, the pole piece 6La, the air gap, the oscillator 3, the air gap, and the yoke 7b and returns to the S pole, while the pole piece 6Lb Since upward magnetic flux (Φ−△Φ) flows through ゛ due to the increase in magnetic resistance of the path, the resultant magnetic flux is the third
From the figure, composite magnetic flux − (Φ + △Φ) − (Φ − △Φ) = 2△φ
Therefore, a voltage is induced in the connected coils 8La and 8Lb.

C&l, when the needle tip is displaced upward, the vibrator 3 approaches the yoke 7a and the pole piece 6Lb, and the permanent magnet 5ON pole connects the pole piece 6Lb with the yoke 7a - air gap - vibrator 3' - air gap - pole piece 6Lb - Air gap yoke 7b
An upward magnetic flux (Φ + △Φ) flows through the pole piece 6La and returns to the S pole, while a downward magnetic flux (Φ - △Φ) flows through the pole piece 6La due to an increase in the magnetic resistance of the path, so the resultant magnetic flux is the third
From the figure, composite magnetic flux = (Φ−△Φ)−(Φ1△Φ)−−2
Coils 8La and 8L b KA connected as △Φ
A voltage in the opposite direction to that in the case of is induced.

That is, according to the present invention, firstly, a soft magnetic material can be used for the vibrator, and the equivalent mass of the vibrating system can be reduced and the characteristics can be improved.

Second, the electrical impedance can be kept low due to the structure, and the electrical transmission characteristics can be improved.

Third, by creating an appropriate air gap between the pole piece and the yoke and controlling the DC magnetic flux Φ passing through the inside of the pole piece, we maximize the reversible magnetic permeability of the pole piece soft magnetic material and improve the linearity of magnetic flux change. can be improved,
It can be expected to prevent magnetostriction and increase output voltage.

Fourth, as shown in FIG. 3, the linearity of the composite magnetic flux change is significantly improved compared to the magnetic flux change of the pole piece with respect to the needle tip displacement, and a reduction in magnetostriction can be expected.

Fifth, because of the structure in which four pole pieces are arranged, two each in the front and rear directions of the two yokes, leakage magnetic flux between the pole pieces that does not pass through the vibrator is extremely small, increasing conversion efficiency. Therefore, an increase in output voltage can be expected.

Sixth, the components of the magnetic circuit can be simplified, and processing and assembly accuracy can be improved.

[Brief explanation of drawings]

FIG. 1 shows the structure of the electromagnetic cartridge according to the present invention, A is a sectional view of the magnetic circuit, B is a front view, FIG. 2 is a diagram of the operating principle of the electromagnetic cartridge according to the present invention, and FIG. An explanatory view showing the relationship between the magnetic flux change inside the pole piece and the resultant magnetic flux change with respect to the needle tip displacement of the mold cartridge. FIG. 4 is a partially sectional perspective view of an embodiment of the electromagnetic mold cartridge according to the present invention. 1...Original needle, 2...Cantilever, 3
... Vibrator, 4 ... Vibration fulcrum position, 5
...Permanent magnet, 5La. 6 Ub, 6 Ra, 6 Rb----Pole piece, 7a. 7b...Yoke, 8La, 8Lb, 8Ra
, 8Rb... Coil, 9... Viscoelastic support.

Claims (1)

[Claims] 1 The above-mentioned vibrator consists of a cantilever with a positioning needle fixed to one end and a vibrator made of a soft magnetic material fitted and fixed to the other end, and a viscoelastic support made of rubber or synthetic resin with an axial hole bored in the center. A permanent magnet made of a hard magnetic material is brought into pressure contact with both magnetic pole surfaces of the permanent magnet, and one end of the permanent magnet is connected to both ends of the vibrator from above the axis of the vibrator. Two yokes made of a soft magnetic material are arranged adjacent to each other, one end of which faces the other end of the yoke through a properly defined gap, and the other end of which is connected to the vibrator from below the axis of the vibrator. The yoke is made of a soft magnetic material and is located adjacent to the end of the transducer, and is located at a front-back symmetrical position of the two yokes when viewed in the axial direction of the vibrator from the positioning needle side, and is also located at a left-right symmetrical position with respect to the vertical plane. It has a magnetic circuit comprising four pole pieces and four coils wound around the pole pieces, and is located approximately in the middle of the portion surrounded by both lower ends of the two yokes and both lower ends of the pole piece. An electromagnetic cartridge characterized in that the above-mentioned vibrator is disposed, and only when the vibrator of the vibration system is displaced, a magnetic flux change is caused in the above-mentioned pole piece, and power is generated in the above-mentioned coil.