JPS58218300A - Moving coil type pickup cartridge - Google Patents

Abstract

PURPOSE:To realize excellent performance and high productivity and to suppress a crosstalk to a minimum, by obtaining a reproduction output by moving two moving coils in a magnetic field by the oscillation of a needle point, and by providing a concave part of separate a magnetic pole. CONSTITUTION:Two circular ringlike moving coils 4 and 5 are fixed to a coil holder 3 whose another end is fixed to a cantilever 2. The moving coils 4 and 5 are inserted to magnetic gaps 22 and 22 between poles 18 and 19 and a front yoke 20. If the coils 4 and 5 are moved, a reproduction output corresponding to the movement of a needle point 1 of the cantilever 2 is obtained. Thus the excellent performance and high productivity are obtained. By providing a concave part 40 to separate a magnetic pole for two magnetic pole surfaces of the front yoke 20 facing to the coils 4 and 5, a vertical direction magnetic flux component can be adjusted to be reduced. Therefore, the maximum magnetic flux density direction, which is a vector sum of the vertical direction magnetic flux component and a horizontal direction magnetic flux component, can be perfectly allowed to coincide with the modulation axis direction of a record to suppress a crosstalk to a minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention has a single stylus tip for tracing record grooves formed substantially at right angles to each other and in which individual signals are recorded. A moving coil type pickup cartridge configured to move two moving coils disposed within a magnetic field in response to mechanical vibrations of the coil, thereby obtaining reproduction output from the two moving coils, which has good frequency characteristics. The object of the present invention is to provide a device that can obtain the following characteristics, and can be easily assembled, so that mass production can be easily performed.

Further, the objectives of the present invention are as follows.

(1) In particular, by effectively reducing the size and weight of the moving coil part without impairing its performance, the effective mass of the vibrator system can be reduced, resulting in wide-band reproduction characteristics with a high limit frequency for high-frequency reproduction, and high-frequency mechanical To obtain a moving coil type pickup cartridge with low impedance.

(2) A low-inductance, low-DC-resistance generating coil and a high-flux-density magnetic circuit with high magnetic flux concentration increase the output sensitivity to impedance ratio, creating a moving-coil pickup cartridge with low noise and high S/N ratio. to get.

(3) With simple shaped coils and coil holders, etc.
To obtain a moving coil type pickup cartridge with high productivity and uniform quality.

(4) To obtain a moving coil type big-up ear tridge that can easily minimize crosstalk due to a simple geometrical arrangement of coils and magnetic poles.

(5) To obtain a moving coil type pickup cartridge with less leakage magnetic flux from a DC magnetic circuit, less attraction phenomenon due to magnetic materials such as a turntable, and no adverse effects such as changes in stylus pressure.

(6) To obtain a moving coil type pickup cartridge that can be easily changed into a configuration in which the needle can be replaced by making the vibrator system and a part of the magnetic circuit blockable.

Conventional structure and problems Generally speaking, as a moving coil type pickup cartridge,
The following two methods have been proposed.

(1) A moving coil type pickup cartridge disclosed in Japanese Utility Model Publication No. 19879/1987.

(2) Japanese Patent Publication, JP-A-46-5577
A moving coil type pickup cartridge disclosed in the publication.

First of all, as shown in FIGS. 1 to 3, the first cartridge disclosed in the above-mentioned Japanese Utility Model Publication No. 4o-19879 has a yoke piece 1o2 and a magnetic pole piece 1 by means of a winter magnet 101. Two coils 105 and 106 are wound directly on the armature 104, which is placed in a DC magnetic field generated between This is the output from the above two coils 105 and 106, but this type of moving coil type cartridge has the following drawbacks: (a) As shown in Figure 3, the needle tip Since it is necessary to wind two coils 105 and 106 around the fixed armature 104, that is, the coil support frame, the cantilever 108 having a cantilever 107, etc. becomes a hindrance, making it difficult to wind the coils and significantly reducing productivity. limited.

Also, the coil 106°106 wound around the armature 104
Since the damper 109 contacts the damper 109, the damping surface of the armature 104 by the damper 109 does not become a uniform plane, making it difficult to uniformly position and brake the armature 104.

(b) In order to increase the output sensitivity, the armature 104 interposed in the magnetic field is made of a magnetic material, but this increases the effective mass of the vibrator and increases the inductance of the coil, narrowing the reproduction frequency band. ,S/N
The ratio becomes worse. In order to suppress this, the number of turns of the coil is limited, and as a result, the ratio of output sensitivity to impedance cannot be increased, and a cartridge with a high S/N ratio cannot be constructed.

(c) A uniform DC magnetic field is generated between the magnetic pole piece 103 and the yoke piece 102, and the armature 104 is inserted into the magnetic field, so essentially the yoke piece 102 has one end fixed to the armature 104. A hole 110 is required to pass through the cantilever 108, and the hole 1
It is necessary to insert the cantilever 108 through the cantilever 10 during assembly. For this reason, it is difficult to assemble the cartridge, and it is also extremely difficult to realize a needle exchange structure.

) Since the yoke piece 102 and the magnetic pole piece 103 are very close to the record surface, the yoke piece 102 and the magnetic pole piece 10
The force attracted to a magnetic body such as a turntable due to the leakage of the DC magnetic flux generated between the three positions increases, which can cause problems such as changes in stylus pressure. Also, since it absorbs iron powder, etc., a protective measure such as a thin rubber film is required.

It has various drawbacks, such as:

On the other hand, the second cartridge disclosed in the above-mentioned Japanese Patent Application Laid-open No. 46-5577 has two fan-shaped coils 111, 112 with arc-shaped effective coil portions 111a and 112a, as shown in FIGS. 4 and 6. This stereo electrodynamic transducer is fitted into an arc-shaped gap 116 formed at the tips of the magnetic pole pieces 113 and 114, and generates an output to the coil according to the movement of the tip 116. Type cartridges also have the following disadvantages: That is, (a) since the coils 111 and 112 are fan-shaped with the effective coil parts 111a and 112a lengthened to increase the output sensitivity, the ineffective coil parts are also inevitably long, and the coils)
Becomes an engineering school. For this reason, the mass of the vibrator is large, the effective mass cannot be reduced, the high frequency reproduction limit frequency 1i is lowered, the mechanical impedance is increased, the reproduction frequency band is narrowed, and the S/N ratio is poor. Also, the coil holding member 11
Since the inactive coil portion coupled to 7 is relatively long, the stiffness of that portion is reduced and harmful resonance is likely to occur.

Furthermore, since the two coils are placed very close together, crosstalk problems are likely to occur.

(b) Also, since the coil is large, the winding length becomes long.
DC resistance increases, resulting in thermal noise and increased connection.
] Noise increases due to an increase in input impedance equal to that of the input stage.

(c) Since the coil is fan-shaped and asymmetrical, it is difficult to manufacture the coil, and attachment to the coil holding member 117 is also very troublesome.

It includes various drawbacks such as.

Purpose of the Invention The present invention is based on the prior art, and in order to eliminate its drawbacks, further research and development has been carried out to create an action coil type that has excellent overall performance, is highly productive, and can be manufactured at low cost. This is a warehouse that provides pickup cartridges.

Structure of the Invention The present invention fixes two circular ring-shaped moving coils to a coil holder to which the other end of the cantilever is fixed, and inserts the moving coils into the magnetic gap between the pole and the yoke. It is configured to obtain a reproduction output according to the movement of the tip of the cantilever, and a recess is provided between the two magnetic pole surfaces of the yoke facing each of the moving coils, and the vertical magnetic flux component is adjusted by the recess. However, the maximum magnetic flux density direction is made to coincide with the modulation axis direction of the record.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIG. 6 and subsequent drawings. The cartridge of this embodiment is a pickup cartridge for playing 45-45 stereo records in which two or more independent signals are recorded in one sound groove, and two independent moving coils vibrate in a DC magnetic field. It uses a moving coil type power generation system that generates an output voltage.

First, a first embodiment of the present invention will be described using FIGS. 6 to 10. The structure of the pickup cartridge can be roughly divided into a vibration system and a power generation system, so the following explanation will be made according to these classifications as much as possible. First, let's start with the vibration system. A cantilever 2 with a needle tip 1 fixed on one end is connected to a roughly disk-shaped coil holder 3 made of synthetic resin. two independent circular ring-shaped coils 4 whose planes are located in a plane perpendicular to the main axis of the cantilever 2;
6 is fixed (see Figure 9). The two coils 4 and 6 are arranged in the plane so that the respective winding centers a and b and the main axis C of the cantilever 2 are approximately at the vertices of a right-angled isosceles triangle (see FIG. 8). 4a, 5a
indicates the output lead wires of coils 4 and 6.

Further, to explain the vibration system in more detail using FIG. 10, a cylindrical protrusion 3a is integrally provided on the front surface of the coil holder 3, and the center hole of the cylindrical protrusion 3a connects the coil holder 3. The other end of the cantilever 2 is press-fitted into a through-hole 6 passing through the cantilever in the thickness direction and fixed by adhesive.

Furthermore, arc-shaped notches 7°7 are provided symmetrically above the outer periphery of the coil holder 3, and the notches 7
7 are provided with coil insertion grooves 8, 8, and the pre-wound circular ring-shaped coils 4, 6 are inserted into these grooves 8, 8 and fixed by adhesive or the like.

As mentioned above, the coil holder 3 has a through hole 6 for coupling the cantilever 2 and coil insertion grooves 8 for fixing the coils 4 and 5, but this coil holder 3 is made of synthetic resin alone. It is manufactured from reinforced plastics containing carbon fiber, glass fiber, etc., or light metals such as aluminum. The coils 4 and 6 are made by winding and hardening into a circular link shape using a self-welding wire that is coated with a conductor of about 15μ to 40μ and coated with adhesive, or a coated conductor and adhesive. In order to reduce the effective mass and direct current resistance as much as possible, the winding diameter is made small and lightweight, and the notches 7, 7 are formed in the cantilever holder 3 so as to be as close as possible to the main axis C of the cantilever 2. Install it using epoxy adhesive, etc. and secure it firmly. If the coil is circular and small, the rigidity can be increased and unnecessary resonance will not occur.

As shown in FIG. 11, the coil holder 3 is integrally provided with a coil support plate 9 having a circular lip 9a, and the rib 9a is
Insert the coils 4 and 5 into the center holes of the coils 4 and 5.
6, the coils 4 and 5 can be easily positioned with respect to the holder 3.

To explain the support structure for supporting such a vibration system, as shown in FIG. 9, a pipe-shaped cantilever 20 is press-fitted into a through hole 6 of a coil holder 3 and fixed with adhesive, and a thin metal wire 2, a synthetic resin filament, etc. is attached to the rear end of the cantilever 20. One end of the support wire 1o is fixed using a connector 11, and inserted into a support pipe 13 with a slight interval 12 provided therebetween and fixed by pressure. And butyl rubber □.

A circular ring-shaped damper 14 made of a viscoelastic material such as:
111: 1・1゛°”nSpecial: KtsO!, “L11C4lii[
! IL/Pipe 13 The support wire 10 fixed to the support pipe 13 is pulled to the rear of the support 16 to optimally adjust the amount of compression of the damper 14, that is, the damping of the vibration system, and then tighten the screw 17 to The pie goo 3 and the support wire 10 are fixed to a support body 16, and the vibration system is supported on the support body 15 so as to be able to freely vibrate. When the vibration system vibrates, the support wire 10 bends at and near the neck portion 10a located within the cavity 12, and the vibration system moves angularly in any direction using the neck portion 10a as a fulcrum. At this time, the support line 1o is not moved in its longitudinal direction. The neck portion 10a has a coil 4.
It is expected that the plane substantially coincides with the plane passing through the center of the thickness direction of the film. The support pipe 13 and the support line 1o that protrude to the rear of the support body 16 may be cut and removed after adjusting the compression amount of the damper (-14) and tightening the screw 17.The front end of the support pipe 13 is connected to a damper. 14 and partially protrudes into the cavity 12.The prior art related to this vibration support structure is disclosed in Japanese Utility Model Publication No. 51-241, which was invented by the present inventor. This prior art is used in an improved form in this embodiment.

Next, a power generation system for outputting an electric signal corresponding to the vibration of the needle tip 1 from the two circular ring-shaped coils 4 and 5 as the vibration system vibrates will be explained. is made of a magnetic material, and cylindrical rod-shaped poles 18 and 19, which are inserted into the center holes of the two coils 4 and 6, are integrally formed on the front surface of the support 16. These poles 18.19 are the 8th
As shown in the figure, the coils 4 and 60 are arranged along central axes a and b. In FIG. 8, the pole 18.degree. 19 and the coils 4, 6 are arranged in a concentric relationship. A front yoke 20 is disposed to face the poles 18 and 19 with the coils 4 and 5 in between, and the front yoke 20 and the pole 18
．． A magnetic gap 21, 22 is formed between the two.

The front yoke 2o and the rear yoke 23 integrally provided on the rear outer periphery of the support 16 are connected by a permanent magnet 24, and the magnetic gap 21 is connected by the permanent magnet 24.
．． A magnetic field is generated at 22.

To explain in more detail, the lower end of the front yoke 20, that is, the part facing the poles 18 and 19 has two coils 4 and 5.
As shown in FIG. 8, magnetic pole faces 26 and 27 are formed facing each of the inverted V-shaped notches 26, which are substantially perpendicular to the two modulation axes of the record, H, and substantially perpendicular to each other. ing. On the other hand, as described above, the two protruding poles 18 and 19 with circular cross sections formed on the front surface of the support body 16 extending forward from the rear yoke 23 are arranged so as to penetrate approximately at the center of each coil 4°6. Therefore, independent magnetic gaps 21 and 22 are formed between the magnetic pole faces 26 and 27 forming the inverted V-shaped notch 26, respectively.

In this magnetic gap 21, 22, the coils 4 and 6 move in response to the mechanical movement accompanying the tracing of the record groove by the stylus tip 1 and cut the DC magnetic flux, allowing each coil to be connected to the left and right channels. A corresponding output voltage is induced. Suppose now that the needle tip 1 vibrates in the direction of adjusting the left channel modulation axis LK in Figure 8 □, -, the coil holder 3 swings around the right channel modulation axis R, Portion 4b within magnetic gap 21
moves to cut the parallel DC magnetic flux, and an electrical output is induced in the coil 4. At this time, the portion 6b of the other coil 6 within the magnetic gap 22 only rotates around the axis R, so the portion 6b of the coil 6 does not cut the magnetic flux, and the output from the coil 6. On the contrary, if the needle tip 1 vibrates in the direction along the right channel modulation axis H, no output is obtained from the coil 4, and an electrical output is induced in the coil 6.In this way, the needle tip 1 vibrates in the direction along the right channel modulation axis H. Corresponding to the first movement, the coils 4 and 6 also separate the left channel signal and the right channel signal and output them.

The power generation system and the vibration system are combined to form a unit as shown in FIG. 7, which is attached to the cartridge body 28 as shown in FIG.
The movable coil type pickup cartridge of this embodiment is completed by connecting the . In FIG. 6, 3° indicates a shield plate, and 31 indicates a screw insertion recess for attaching the cartridge to a head shell (not shown).

The above is the explanation of the cartridge of this embodiment, and a supplementary explanation will be given below. In general, the weight of the cartridge has a large effect on the effective mass (affecting frequency characteristics) of the tone arm system including the cartridge, so the weight of the cartridge should not be unnecessarily large (if it is too large, the reproduction frequency band will be narrowed). The moving coil type pickup cartridge normally uses a sintered magnet as a magnet for generating a magnetic field, which has the disadvantage of being too heavy and narrowing the reproduction frequency band. In order to avoid this, in this embodiment, a rare earth cobalt magnet such as a samarium cobalt magnet, which is characterized by high coercive force and high (BH) max, is used to obtain a strong gap magnetic field and to reduce the size and weight of the magnet. Of course, magnets made of other materials may be used without any problem.

Front yoke 20 constituting a magnetic circuit. The support body 16 with the rear yoke 23 and poles 18 and 19 is made of a magnetic material such as electromagnetic pure iron, permendur, or ferrite, which has a large saturation magnetic flux density and high magnetic permeability, but similar materials can be made of powder. It can also be manufactured using a sintering method, which involves molding, molding, and sintering.

In particular, the support 1 with the rear yoke 23 and the poles 18, 19
By integrally molding and manufacturing 6 using a sintering method, assembly accuracy can be significantly improved and the number of man-hours can be reduced. The same applies to the front yoke 20, but it goes without saying that it may be manufactured using other methods such as press working.

By the way, in the first embodiment described so far, the support body 16 for supporting the vibration system forms part of the magnetic line for generating a magnetic field in the magnetic gap between the poles 18 and 19 and the front yoke 20. Therefore, at least the portion of the support 16 that connects the poles 18, 19 and the rear yoke 23 must be made of a magnetic material. However, in the second embodiment shown in FIGS. Even if the support body 15 is made of a non-magnetic material such as synthetic resin, it does not interfere with the reproducing operation.

The second embodiment will be described with reference to FIGS. 12 and 13. The base 3 protrudes forward on the front side of the lower end of the rear yoke 23.
2 is integrally formed with the rear yoke 23 by a sintering method, and the base 3
Circular grooves 34 and 36 are provided on the circumference of the center through-hole 33 of No. 2, and a cylindrical support 36 and pole bins 37 and 38 made of magnetic or non-magnetic material are installed in these holes 33 and grooves 34 and 36. Each is inserted and fixed to form one magnetic pole part. In this case, the support pipe 13 connected to the vibration system described above is inserted into the center hole 16 of the support 36, and after adjusting the amount of compression of the damper 14, it is fixed with screws 17 to assemble the vibration system. 3e is inserted into the hole 33 of the base 32 and fixed with the screw 39, making assembly easy.

By the way, in order to improve the separation characteristics between the left and right channel outputs, which is an important performance for a pickup cartridge for playing back stereo records, the geometrical arrangement of the vibration system: 1 is important. That is, as shown in Fig. 8, it is necessary to construct the coil so that the line connecting the center of the coil a'l::'Q El and the needle tip 1 coincides with the direction of the record i''A modulation axis and the R axis. , usually need to be arranged at an angle of 46.90 to each other with respect to the record surface.The operation in this case is explained as follows: When the stylus tip moves along the axis H due to modulation in the 45 left direction, the coil 4 Effective coil portion 4 of
a moves in parallel in the front-back direction and generates an output voltage within the magnetic gap 21, but the coil 6 rotates around the axis R within the coil plane and therefore does not generate an output voltage. Therefore, good separation of left and right outputs is achieved. In addition, when the needle tip moves by vertical modulation, it is in phase with coils 4 and 6,
and produces the same level of output. Furthermore, in the case of horizontal modulation, coils 4 and 6 move back and forth in opposite directions to each other, resulting in outputs of the same level in opposite phases.However, in order to obtain an in-phase signal for horizontal modulation, one coil is reversely moved. Connect to the other coil so that they are in phase.

Another important factor is the shape of the notch 25 of the front yoke 20. □, 1 The direction in which the density of the magnetic flux generated between the narrow protruding magnetic poles 18゜", 19 and the front yoke 20 is maximized corresponds to the modulation axis direction of 3:', . If the shape of the notch 25 is set as shown, it is possible to improve the separation properties of the left and right channels and the channel separation.For example, as shown by dotted lines in FIGS. 7 and 8, the four parts 40 for separating the magnetic poles can be By providing , it is possible to adjust the magnetic flux component in the vertical direction (vertical direction in Fig. 8) to decrease, so that the magnetic flux component in the vertical direction and the horizontal direction (
The direction of the maximum magnetic flux density, which is the vector sum of the magnetic flux components in the left-right direction in FIG.

To make this easier to understand, this will be explained with reference to FIG. 18.If the opening width and depth of the recess 4o is increased, the magnetic flux component in the vertical direction will be reduced accordingly, and the coil 4 of the recess 4o, As the number of magnetic pole faces facing the side surface of the record increases, the magnetic flux component in the horizontal direction increases accordingly, so the direction of the maximum magnetic flux, which is the vector sum of the vertical component and the horizontal component, is made to coincide with the modulation axis direction of the record, R. You can do it like this.

Next, another example of the support wire 10 portion forming the vibration fulcrum of the vibration system will be described with reference to FIGS. 14 and 16.
In the example shown in FIG. 4, the coil holder 3 and the support wire 10 are integrally molded from synthetic resin, and the support vibrator 13 is attached and fixed to the support wire 10. In the example shown in FIG. 16, a recess 41 is provided on the rear surface of the holder 3 in order to bring the flexible neck portion 10a, which serves as a vibration fulcrum, as close to the surface containing the coils 4 and 5 as possible, and the front end of the support pipe 13 is partially inserted into the recess 41. It's being invaded.

The latter structure has the same el as the structure of the first embodiment shown in FIG.

Next, FIG. 16 shows a third embodiment of a moving coil type pickup cartridge in which the needle can be replaced. In the cartridge of Conventional Example 1 explained at the beginning, as shown in FIG. In addition, the yoke piece 1o2 requires a hole that passes through the cantilever 108, making it extremely difficult to replace the needle.In addition, since the magnetic pole is close to the record surface, leakage magnetic flux causes iron powder to be attracted, so it is necessary to have a hole that passes through the cantilever 108. A thin film of Furthermore, in the case of a turntable that includes a magnetic material, the cartridge is likely to be attracted, causing problems such as changes in stylus pressure. However, according to the cartridge of this embodiment, the yoke 2
There is no need for a hole to penetrate the cantilever 2 at the tip of the cantilever 2,
Since it opens downward, it has the advantage of making it easy to replace the stylus, and since the magnetic pole is separated from the record surface, there is no suction phenomenon as described above, and there is no need for a dustproof thin film.

Therefore, the structure in which the needle can be replaced will be explained using FIG. 16. When assembling the vibration system, the output lead wires 4a and 5a of the coil 4.6 are housed in the slit groove 42 provided on the outer periphery of the support 36 and supported. Four terminal pins 43 are attached to the rear end of the body 36.
The needle terminal portion 44 having the above lead wires 4a, 5 is fixed.
Connect a to the terminal pin 43. This support 13 is the base 3
2 into the hole 33. On the other hand, the cartridge body 28
Four jacks 46 into which the terminal bins 43 are press-fitted into a terminal plate 46 formed in are connected with a lead wire 48, and in order to facilitate needle exchange, the support 36 is integrated with a needle holder 49 made of synthetic resin, light alloy, etc.
This holder 49 is attached to the main body 28 with fixing screws 50.

When replacing the needle, loosen the fixing screw 60 and pull out the support 36 integrated with the hook holder 49 forward, and the entire vibration system including the 4-point 1 can be easily replaced. As shown in Fig. 17, the shape of the magnetic pole faces 26 and 27 of the pole 20 is an arc concentric with the center of the pole 18 and 19, so that the effective coil portion is relatively longer and the output voltage is increased. Moyoi 0 Detailed Description of the Invention As described above, the moving coil type pickup cartridge of the present invention has the moving coil formed independently in a simple circular ring shape, and the coil, L, which is fixed to the holder. This coil holder is 1
, :,.

A magnetic gap is formed between a pole inserted into the center hole of the coil and a yoke opposed to this pole, and a magnetic gap is generated within this magnetic gap. The above-mentioned coil is moved in a direct current magnetic field to extract output, and in particular, the coil holder is movably supported around its center as a fulcrum, thereby reducing the effective mass of the vibrator system. By making the movable coil into a circular ring shape and generating a magnetic field in the radial direction of this coil,
The objectives of (1) to (6) mentioned at the beginning are (1) to obtain a moving coil type pickup cartridge that has wide-band reproduction characteristics with a high high-frequency reproduction limit frequency and low mechanical impedance in the high-frequency range; (2) output To obtain a moving coil type pickup cartridge with a large sensitivity-to-impedance ratio, low noise, and high S/N ratio, (3) To obtain a moving coil type pickup cartridge with high productivity and uniform quality, (4) To obtain a coil and To obtain a moving coil type pickup cartridge that can easily minimize bending and stalking by a simple geometrical arrangement of magnetic poles; (5) leakage magnetic flux from a DC magnetic circuit is small, and attraction phenomenon caused by magnetic materials such as turntables is prevented; To obtain a moving coil type pickup cartridge that has a small amount of stylus pressure and no adverse effects such as changes in stylus pressure.
6) The transducer system and part of the magnetic circuit can be made into blocks, and the moving coil type pickup cartridge can be easily changed to a configuration with replaceable needles.It has excellent performance and is easy to assemble. It is possible to provide an excellent and unprecedented moving coil type pickup cartridge.

In other words, from a performance standpoint, for example, the reproduction frequency band can be manufactured separately from the coil holder, and since the coil is simply circular, high-speed winding work is easy and quality can be easily maintained. Mass production can be carried out by introducing machines, and in this case, variations in performance of the obtained cartridges can be greatly reduced.

Further, according to the present invention, since a recess for separating the magnetic poles is provided between the outer periphery of each of the two yokes and the magnetic pole surface of the opposing yoke, the vertical magnetic flux is The maximum magnetic flux density direction, which is the vector sum of the vertical magnetic flux component and the horizontal magnetic flux component, can be adjusted in the direction of decreasing the magnetic flux component, and as a result, the maximum magnetic flux density direction, which is the vector sum of the vertical magnetic flux component and the horizontal magnetic flux component, can be perfectly aligned with the modulation axis direction of the record. Therefore, crosstalk can be minimized and separation between left and right channels can be made sufficiently good.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing an example of a conventional moving coil type pickup cartridge, Fig. 2 is a side sectional view of the same main part, and Fig.
4 is a side view showing another example of the conventional moving coil type pickup cartridge. FIG. 6 is a front view of the coil portion. FIG. 6 is a first embodiment of the present invention. FIG. 7 is a perspective view of the essential parts, FIG. 8' is a front view of the essential parts, FIG. 9 is a side sectional view of the essential parts, and FIG. 10 is the vibration of the moving coil type pickup cartridge in the example. FIG. 11 is a partially exploded perspective view showing another example of the same vibration system; FIG. 12 is a side sectional view of the essential parts of a moving coil type pickup cartridge in a second embodiment of the present invention; FIG. 13 is an exploded perspective view of the same essential parts, FIGS. 14 and 16 are side sectional views showing other examples of the support structure of the vibration system, and FIG. 16 is a moving coil type pickup in a third embodiment of the present invention. FIG. 17 is a side sectional view of the cartridge, FIG. 17 is a front view of the fourth embodiment, and FIG. 18 is an explanatory diagram illustrating the principle of matching the maximum magnetic flux direction with the modulation axis direction of the record. 1... Needle tip, 2... Cantilever, 3
......Coil hole f-, 4, 5...Moving coil, 18,19...Pole, 20...
... Yoke, 21.22 ... Magnetic gap, 2
4... Permanent magnet, 4o... Concavity. Name of agent: Patent attorney Toshio Nakao and one other person i□ 1:1.1 -・-. Figure 1 Figure 2 Figure 3 Figure 4 Figure 13 Figure 6 Figure 7 Figure 10 Figure 12 Figure 13 Figure 14 Figure 4.5 Figure 15 Figure 16 Figure 17

Claims (1)

[Claims] The other end of the cantilever with the needle tip fixed at one end is fixed to a coil holder, and this coil holder is movably supported by a support means with the center of the coil holder as a fulcrum, and the movable coil is moved in a circular/gular shape. The two circular ring-shaped moving coils are arranged around the outer periphery of the coil holder so that the plane of the winding is substantially perpendicular to the axial direction of the cantilever, and the center of the winding is approximately parallel to the cantilever. A magnetic gap is formed between a pole fixed to form a right isosceles triangle and passed through the center hole of the circular ring-shaped movable coil and the movable coil at a yoke facing the pole; A permanent magnet is interposed in a line magnetically connecting the pole and yoke to generate a magnetic field in the magnetic gap, and the movable coil disposed in the magnetic gap responds to the mechanical vibration of the needle tip. A moving coil type pickup cartridge configured to obtain a reproduction output, and characterized in that a recess for separating the magnetic poles is provided between the outer periphery of each of the two moving coils and the magnetic pole surface of the yoke that faces each other. .