JPS6035360Y2 - Moving coil type pick-up cartridge - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a moving coil type pickup cartridge in which a power generating coil is moved linearly in a magnetic field.

In the moving coil type pickup cartridge, in which the generating coil is moved linearly in the magnetic field, the gap between the magnets forming the magnetic field can be configured to be narrow, and the magnetic flux density in the magnetic field can be high. Since the coil can cut the magnetic flux orthogonally, it has the characteristic that a high output voltage can be obtained overall.

Therefore, in this type of pickup cartridge, the generating coil can be constructed from a so-called air-core coil instead of being wound around a winding frame made of a magnetic material, which makes it possible to reduce the equivalent mass of the vibration system and improve compliance and tracker performance. Excellent properties such as stability can be obtained.

However, in the conventional pickup cartridge of this type, the arrangement of the generating coil in the magnetic field is such that only half 1a of the coil 1 is exposed to the magnetic field, as shown in FIG.
said half 1a when the coil 1 vibrates.
cuts off the magnetic flux B, so that a voltage is induced in this coil 1.

That is, if the entire coil 1 is placed in the magnetic field 2, the induced voltages cancel each other out and no output voltage can be obtained.

In such a configuration, the voltage conversion characteristic of the coil 1 is asymmetric between the half portion 1a in the magnetic field 2 and the half portion 1a outside the magnetic field 2, which causes distortion.

In addition, in the configuration shown in FIG. 1, the magnetic field 2 is formed by arranging a pair of magnets (not shown) facing each other, but normally the magnets have leakage magnetic flux, so the magnetic field 2
It is impossible to draw a straight line between the two, and as shown in FIG. 2, a magnetic field is formed outside the magnetic field 2 due to the leakage magnetic flux.

The magnetic field due to the leakage magnetic flux is generated in the half portion 1b of the coil 1.
This induces a voltage in the opposite direction to the voltage in the half portion 1a, reducing power generation efficiency.

Therefore, in the configuration in which half of the power generation coil is placed in the magnetic field, there are problems in signal quality, power generation efficiency, etc. that need to be improved.

By the way, as a moving coil type pickup cartridge that attempts to solve the above-mentioned problem, the one shown in FIGS. 3 and 4 (provided in Japanese Utility Model Application Laid-Open No. 52-73703) is known.

That is, as shown in FIG. 3, a pair of magnets 5ae5b whose central and outer peripheral parts are magnetized differently are placed opposite each other to create magnetic fields 6a and 6b in which the direction of the magnetic flux is in the direction of the magnetic pole surfaces of the magnets 5a and 5b. A coil 9 formed on a coil support 7 (fixed to a cantilever 8) is placed in these magnetic fields 6a and 6b, and as shown in FIG. When the coil 9 vibrates in the opening direction of the magnetic pole 5b (the front-rear direction in this drawing), the half parts 9a and 9b of the coil 9 absorb the magnetic flux B of the magnetic fields 6a and 6b, respectively.
1. B2 is cut so that voltages in the same direction are induced in each half 9a and 9b.

However, in this configuration, since the vibration direction of the coil 9 is the magnetic pole opening direction of the magnets 5a and 5b, it is not possible to configure the spacing between the magnets 5a*5b to be narrow.

As a result, the magnetic flux density in the magnetic fields 6a, 6b becomes small, resulting in a disadvantage that a high output voltage cannot be obtained.

In view of the above-mentioned circumstances, this idea was developed to create a moving coil type pickup that can narrow the spacing between the magnetic poles of the magnet to obtain a high magnetic flux density of the magnetic field, while also allowing the coil to perform pish-pull operation to obtain a high output voltage. The present invention provides a moving coil pickup cartridge in which a coil connected to a cantilever is moved linearly in a magnetic field. The coil is arranged along the corresponding imaginary plane, and substantially the entire front half of the coil in the vibration direction is arranged between the magnetic pole end faces of the different magnetic poles of the first and second magnets, and substantially the entire rear half of the coil is arranged between the pole tips of the different magnetic poles of the first and second magnets. The magnetic poles of the first and second magnets are arranged between the magnetic pole faces of different magnetic poles of the third and fourth magnets, and the first and third magnets are adjacent to the second and fourth magnets, respectively. The directions of the magnetic fields formed between the end faces and between the pole end faces of the third and fourth magnets are reversed.

An embodiment of this invention will be described below with reference to FIGS. 5 to 9.

FIG. 5 shows a pickup cartridge A according to this invention, in which a cantilever 11 having a needle tip 10 at its tip is attached to a support member 12 at its base end.

Left and right coil units 13a and 13b are attached to the support member 12, which are inclined at 45 degrees to the left and right with respect to a vertical plane passing through the axis of the cantilever 11, and project diagonally upward to the left and right.

Magnet blocks 14a, 15a, 14b are provided on both sides of the coil units 13a, 13b, with the coil units 13a, 13b sandwiched therein over the entire area.
, 15b are arranged facing each other.

As shown in FIG. 6, in the coil unit 13a, a spiral coil 11 made of a conductive material such as copper or aluminum is formed on one side of a coil support 16 made of silicon in the form of a square plate by photo-etching or the like. It is formed by means.

As shown in the figure, the magnet block 14a includes rectangular plate-shaped magnets 18 each magnetized in the direction in which the plate surface opens.
．． Similarly, the magnet block 15a is formed by bonding 20 the magnets 19 and 20 with an adhesive or the like.Similarly, the magnet block 15a is formed by rectangular plate-shaped magnets 21 and 22 each magnetized in the direction in which the plate surface opens.
It is formed by adhering 23.

As shown in the figure, the magnet blocks 14a and 15a have the coil unit 13a placed therein, and the magnets 18 and 21 are opposed to each other at the front half 17a of the coil 17 in the coil unit 13a.
Magnet 19 and magnet 2 in the second half 17b of 7
2 are placed facing each other.

In this case, the magnetized state of each of the magnets 18, 19, 21, and 22 is as shown in FIG.
The magnetic field 25 formed by the magnet 22 and the magnet 22 are magnetized so that the directions of the magnetic fluxes existing in the mutually opposing magnetic pole opening directions are in opposite directions.

That is, the magnetic field 24 (first magnetic field) in which the front half 17a of the coil 17 is located is between the S pole of the magnet 18 on the magnet block 14a side and the magnet block 1.
The magnetic field 25 (second magnetic field) formed by the N pole of the magnet 21 on the 5a side and the rear half 17b of the coil 17 is located is formed by the N pole of the magnet 19 on the magnet block 14a side and the magnet block 15.
It is formed by the S pole of the magnet 22 on the a side.

At this time, the magnetic flux in each magnetic field 24, 25 is parallel to the coil axis of the coil 17 (the coil axis is a virtual axis indicating the direction of the magnetic flux that most effectively induces an electromotive force in the coil).

On the other hand, the configuration of the coil unit 13b and the magnet blocks 14a and 15b is as described above in the coil unit 13a.
and magnet block 14a.

15a, and the arrangement state thereof is such that the coil unit 13a and the magnet block 14a are arranged centering on a vertical plane passing through the axis of the cantilever 11.
*It is arranged symmetrically with 15a.

Then, the needle tip 10, the cantilever 11, the support member 1
2 and coil unit 13a.

Reference numeral 13b constitutes a vibration system of this pickup cartridge, and in this vibration system, the coil units 13a and 13b are positioned when the stylus 10 captures a signal as mechanical vibration from the sound groove of a record (not shown). The coil 17 is directed linearly in the front-back direction along the surface, that is, in a direction substantially parallel to the axial direction of the cantilever 11, that is, the coil 17
4.25, and is appropriately supported so as to cut the magnetic flux at right angles to it.

Based on the above configuration, this pickup cartridge A
In this case, the mechanical vibration of the needle tip 10 causes the cantilever 11 to
, coil units 13a, 13b via the support member 12
A voltage is induced in each coil 17, 17 of these coil units 13a, 13b.

To explain this state with reference to FIG. 8, the coil 17 moves linearly in the direction of the arrow shown in the magnetic field 24, 25, but at this time, the front half 17a of the coil 17 cuts the magnetic flux a in the magnetic field 24. A voltage is induced in the first half 17a of the lever,
The rear half 17b of the coil 17 cuts the magnetic flux B2 in the magnetic field 25, and a voltage is induced in this rear half 17b.

Here, since the directions of the magnetic flux B1 and the magnetic fluxes are opposite to each other, the voltage induced in the front half 17a and the voltage induced in the rear half 17b are in phase, and the coil 17 has these voltages added to it. will be obtained as the output voltage.

That is, the coil 17 has a front half 17a and a rear half 17.
The output voltage is obtained by the push-pull operation of .b and .b.

In this case, the magnetic flux distribution between the magnetic fields 24.25 and 24.25 is as shown by the solid line in FIG. 9, and compared to the conventional example shown in FIG. are clearly divided, and the magnetic flux of each magnetic field 24.25 is effectively utilized.

In this way, a voltage is induced in each coil 17, 17 of the coil units 13a, 13b, but since these coil units 13a, 13b are arranged at an angle of 45 degrees left and right with respect to the vertical plane passing through each cantilever 11, , a left channel signal is obtained from the coil 17 of the coil unit 13a, and a right channel signal is obtained from the coil 17 of the coil unit 13b.

Next, another embodiment of this invention will be described with reference to FIG.

In this figure, the same parts as in the above embodiment are designated by the same reference numerals.

Figure 10 shows a pickup cartridge B based on this invention.
A cantilever 11 having a needle tip 10 at its tip is
Its base end is attached to a support member 12, and the support member 12 includes a vertical coil unit 51 and a cantilever 11 disposed along a vertical plane passing through the axis of the cantilever 11.
Left and right horizontal coil units 52a and 52b are fixed, which are arranged along a plane passing through the axis of the plane and orthogonal to the vertical plane.

In this case, the coil unit 51 and the coil unit 5
2a and 52b are coil units 13 suitable for the above embodiments.
It has the same configuration as a (or 13b), and each coil unit 5L 52 is centered around the cantilever 11.
Magnet blocks 53 to 56 are arranged annularly in the circumferential direction where ay 52b is located.

Each of the magnet blocks 53 to 56 is made by bonding two front and rear magnets into one unit, and a magnetic field is formed between the magnet blocks 53 and 54 with the vertical coil unit 51 therein, and a horizontal coil is formed between the magnet blocks 54 and 55. A magnetic field containing the unit 52a is formed, and a magnetic field containing the horizontal coil unit 52b is formed between the magnet blocks 53 and 56.

In this case, the magnetized state of the front and rear of each magnet in the magnet blocks 53 to 56 is such that a magnetic field similar to the magnetic field 24, 25 described in the previous embodiment is formed in the portion where each coil unit 51, 52a, 52b is located. It is magnetized so that

Based on the above configuration, this pickup cartridge B
In this case, a voltage is induced in each coil of the vertical coil unit 51 and the horizontal coil units 52a*52b by the vibration of the vibration system due to the push-pull operation similar to the previous embodiment.

In this case, due to the arrangement of the coil units 51, 52a, 52b, voltage is induced in the coil of the vertical coil unit 51 only by vibration in the vertical direction, and voltage is induced in the horizontal coil units 52a, 52b only by vibration in the horizontal direction. A voltage is induced.

Here, in the sound groove of a record, the sum signal of the left and right channel signals is carved in the horizontal direction, and the difference signal of the left and right channel signals is carved in the vertical direction, so for example, the vibration in the horizontal direction obtained by the horizontal coil unit 52a The left channel signal output is obtained by obtaining the sum voltage of the voltage caused by the vertical vibration obtained by the vertical coil unit 51 and the voltage caused by the horizontal vibration obtained by the horizontal coil unit 52b. A right channel signal output can be obtained by obtaining a voltage difference between the vertical vibration voltage and the voltage obtained by the vertical coil unit 51.

In each of the above embodiments, the magnet blocks 14a and 15a (51 to 56) were constructed by bonding two magnets each, but instead of this, for example, barium ferrite, rare earth cobalt (samarium cobalt), etc. A magnet having two different magnetic poles on the same surface may be constructed by using fine powder such as .

As is clear from the above explanation, according to this invention, a coil that is flat in the coil axis direction is arranged along a virtual plane corresponding to a predetermined vibration direction, and approximately the entire first half of the coil in the vibration direction is is arranged between the magnetic pole end faces of different magnetic poles of the first and second magnets, and substantially the entire rear half of the same coil is arranged between the magnetic pole end faces of different magnetic poles of the third and fourth magnets, and 11 Third magnet and second and fourth
The magnets are arranged adjacent to each other, and the directions of the magnetic fields formed between the pole end faces of the first and second magnets and between the pole end faces of the third and fourth magnets are opposite. , the magnetic flux density of each magnetic field is extremely high, and these magnetic flux densities are uniform throughout the first half and the second half of the coil, and the boundaries between the respective magnetic fields are clear. The area between each magnetic pole end face of the magnet can be used as an effective magnetic gap for push-pull, and the area of the coil placed between these magnetic gaps can be made small (i.e., compact) and high output can be achieved. Obtainable.

This effect is particularly effective when the coil is a spiral coil in which the winding is formed up to the center.

Furthermore, according to this invention, since the magnetic flux density of each magnetic field is uniform, it is possible to obtain high-quality output with little distortion.

Furthermore, according to this invention, since the entire area of the coil is completely sandwiched between the magnets, it is not affected by leakage magnetic flux from the outside at all.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the power generation principle of a conventional moving coil type pickup cartridge, and Fig. 2 is a graph showing the state of magnetic flux distribution in the same pickup cartridge.
Fig. 3 is a sectional view of a main part showing an example of a conventional moving coil type pickup cartridge in which the power generating coil is configured to perform push-pull operation, Fig. 4 is an explanatory diagram showing the power generation principle of the same pickup cartridge, and Fig. 5
The figure is a perspective view of the pickup cartridge A according to this invention, FIG. 6 is an explanatory diagram showing the arrangement relationship between the coil unit and the magnet block in the same pickup cartridge, and FIG. 7 is a view seen from the direction of the arrow ■ in FIG. 5. FIG. 8 is an explanatory diagram showing the power generation principle of the pickup cartridge A, FIG. 9 is an explanatory diagram showing the distribution of magnetic flux of the magnetic field in the pickup cartridge A, and FIG. 10 is a perspective view of the pickup cartridge B according to the invention. be. 11... Cantilever, 12... Support body, 13a, 13b... Coil unit, 14
a, 15a...Magnetic block, 17...
...Coil, 18.19,21,23...
Magnet, 24...Magnetic field (first magnetic field), 2
5... Magnetic field (second magnetic field), 51...
Vertical coil unit, 52a, 52b... Horizontal coil unit, 53-56... Magnet block.

Claims (1)

[Scope of utility model registration request] A support member is attached to the base end of a cantilever having a needle tip at the tip, and a flat coil is attached to the support member in the direction of the coil axis with the coil axis orthogonal to a virtual plane passing through the axis of the cantilever. , is provided along the same virtual plane, supports a vibration system including the coil and the cantilever so as to be able to vibrate, and has one magnetic pole surface of the first magnet sandwiching substantially the entire front half of the coil in the axial direction of the cantilever. and one magnetic pole surface of the second magnet are arranged to face each other, and the one magnetic pole surface of the first magnet and the one magnetic pole surface of the second magnet are configured to have different magnetic polarities. , a unidirectional magnetic field parallel to the coil axis is formed in substantially the entire area of the front half of the coil by these two magnets, a third magnet is disposed adjacent to the first magnet, and the second magnet A fourth magnet is disposed adjacent to the coil, and one magnetic pole surface of the third magnet and one magnetic pole surface of the fourth magnet are disposed opposite to each other with substantially the entire rear half of the coil in between. The one magnetic pole face of the third magnet and the one magnetic pole face of the first magnet are configured to have different magnetic polarities, and the one magnetic pole face of the third magnet and the fourth magnetic pole face are configured to be different from each other.
The third magnet and the fourth magnet are configured to have different magnetic polarities from the one magnetic pole surface, and the third magnet and the fourth magnet cover substantially the entire rear half of the coil in a direction opposite to the one direction magnetic field. , and are adjacent to each other and form a magnetic field parallel to the coil axis, so that when the coil vibrates approximately parallel to the virtual plane, the first half and the second half of the coil differentially move. A moving coil type pickup cartridge characterized by being configured to generate electricity.