JPH0434878B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a moving coil type (MC type) cartridge.

BACKGROUND TECHNOLOGY AND PROBLEMS FIG. 1 shows the structure of a conventional moving coil type cartridge, in which a magnet 1,
A magnetic circuit is formed by yokes 2 and 3 made of soft magnetic material and an air gap 4 provided between these yokes 2 and 3. In addition, a needle tip 5 is attached at a predetermined angle to one end, and an armature is attached to the other end.
Cantilever 7 with integrally provided coil 6
is attached to the yoke 3 by a tension wire 8 in a movable state with the other end serving as a fulcrum of movement. Therefore, when the above-mentioned coil 6 vibrates or rotates within the magnetic field of the air gap 4, a voltage is induced in the coil 6 because the coil 6 cuts the magnetic flux, and the conversion method is proportional to the moving speed of the armature. is taken.

However, in such conventional moving coil type cartridges, it is necessary to guide the magnetic flux from the S and N poles of the magnet 1 through the yokes 2 and 3, so the number of parts in the cartridge increases and the cartridge becomes large. There is a drawback.
Furthermore, since the yokes 2 and 3 for forming the magnetic circuit must be processed with great precision, there is a problem in that the manufacturing cost of the cartridge increases.

Purpose of the Invention The present invention was invented in view of the above-mentioned circumstances, and by adopting a completely new configuration, it has excellent characteristics despite being extremely simple in structure. The purpose is to provide a small and inexpensive moving coil type cartridge.

SUMMARY OF THE INVENTION A moving coil type cartridge according to the present invention has a pair of cylindrical magnets each having magnetic poles formed in the axial direction, and the magnetic poles of the same polarity are closely opposed to each other and arranged on the same axis. A fulcrum of motion of a movable part having a coil is placed on the central axis of the magnet, and a voltage is induced in the coil by a magnetic flux component generated from the opposing portion of the magnet in a direction orthogonal to the central axis. . With this configuration, a magnetic field with high magnetic flux density can be obtained with a simple configuration, and high output can be obtained.

Embodiment An embodiment of a moving coil type cartridge to which the present invention is applied will be described below with reference to FIGS. 2 to 7.

FIG. 2 is an exploded perspective view of the moving coil type cartridge of the embodiment, FIG. 3 is a perspective view showing the appearance of the assembled state, and FIG. 4 is a longitudinal sectional view.

As shown in FIGS. 2 and 4, the cartridge of this embodiment has a pair of cylindrical magnets 11,
12 is used to obtain the magnetic flux necessary for power generation. Each cylindrical magnet has an S pole and an N pole formed in its axial direction, and magnetic poles of the same polarity (for example, N pole)
They are adhesively fixed inside non-magnetic magnet cases 32 and 33 while facing each other and disposed on the same axis. Therefore, the N of magnets 11 and 12 respectively
The magnetic flux generated from the entire area of the poles (opposing surfaces) is concentrated and diverges from the circumferential surface (boundary line) of the opposing portion of the magnetic poles. Therefore, a strong magnetic field (with high magnetic flux density) perpendicular to the axial direction is formed in the space near the opposing portions inside the cylindrical magnets 11 and 12.

Magnets 11, 12 and magnet case 3
A cantilever 13 and an armature 15 are arranged in one opening of the cylindrical body made up of the cylindrical body 2 and 33, and the other opening is closed with a cylindrical magnetic member 10. This magnetic member 10 is a cantilever 1
3 and forms part of the magnetic path of the main magnet 11. Therefore, the magnetic member 10 is
It is made of a magnetic material (soft magnetic material such as pure iron or permalloy) with high magnetic permeability. A ring-shaped convex portion 10a is formed on one end surface of the magnetic member 10, and flanges 32a on one end of the magnetic cases 32, 33,
It is fitted onto the inner circumferential surface of 33a without any play, and both are fixedly arranged on the same axis.

A needle tip 14 is attached to one end of the cantilever 13 at a predetermined angle using, for example, epoxy adhesive, and an armature 15 is coaxially fixed to the other end. This cantilever 13 is configured to be movable in each direction using its rear end as a fulcrum. That is, as clearly shown in FIGS. 2 and 4,
The cantilever 13 is made of a pipe-like member, and a sleeve 17 is press-fitted into a hollow portion 16 at its rear end. The tip of a tension wire 18 made of piano wire or the like is inserted into the sleeve 17 and fixed to the sleeve 17 using, for example, an epoxy adhesive.

The latter half of the tension wire 18 is inserted into a sleeve 21 that is press-fitted into a brass cylindrical member 20, and its tip is adhesively fixed to the sleeve 21 with, for example, an epoxy adhesive. Also, a sleeve 2 protruding from one end of the cylindrical member 20
The protruding portion 21a of No. 1 is caulked. Therefore, the wire 18 is fixed at three points: both ends thereof and a location corresponding to the crimped portion described above. The length of the wire portion 18a between the protruding portion 21a and the armature 15 is, for example, about 0.2 mm.

Further, as clearly shown in FIG. 4, the above-mentioned cylindrical member 20 is inserted into the center hole 22 of the magnetic member 10 and is fastened and fixed with a screw 23. The armature 15 is disposed on the same axis as the magnetic member 10 and the magnets 11 and 12, and is disposed on the inner peripheral surface side of the opposing portions of the magnets 11 and 12 with the same polarity.

A rubber damper 24 is interposed within the hollow portion 11a of the magnet 11 and between the armature 15 and the convex portion 10a of the magnetic member 10. Therefore, the cantilever 13 and the armature 15 are moved by the elasticity of the wire portion 18a.
It is movable in each direction using 8a as a fulcrum of movement.

On the other hand, as shown in the front view of FIG. 6, the armature 15 described above includes a coil bobbin 25 made of hard resin such as polycarbonate and coaxially attached to the rear end of the cantilever 13, and a coil bobbin 25 wound around the coil bobbin 25. It is composed of coils 26a to 26d. A groove 27 for coil winding is formed on one end surface of the coil bobbin 25, and a stepped portion 27 for coil winding is formed on the circumferential surface of the other end.
8 is formed. The wire 29 constituting the coil 26 is wound in sequence in the direction shown by the arrow in FIG. 6, and the left channel coils 26a and 26c facing each other are wound in a so-called figure-eight shape. In addition, in Fig. 6, the wire rod 29 is
Although it is only wound once, it is actually wound many times in order to obtain the required sensitivity. In addition, in FIG. 6, the right channel coils 26b, 26
Although d is omitted from the illustration, these also correspond to the above-mentioned coil 26.
It is wound around the coil bobbin 25 in exactly the same way as coils a and 26c.

Further, as shown in FIGS. 2 and 4, an aluminum pipe 31 is fitted and fixed to the rear end portion of the cantilever 13, and an armature 15 is coaxially fitted and fixed to this aluminum pipe 31. The reason why the aluminum pipe 31 is interposed between the rear end portion of the cantilever 13 and the armature 15 is to provide a damping effect to the rear end portion, that is, the root portion of the cantilever 13.

On the other hand, the coils 26a to 26 of the armature 15
As shown in FIGS. 3 and 4, d is arranged in a hollow portion of the inner circumferential surface near the opposing portions of the magnets 11 and 12 having the same polarity. That is, the coils 26a-2
Of the wire rods 29 constituting the wire rod 6d, the wire rod portion 29a wound around the circumferential surface of the coil bobbin 25 is as follows:
The wire portion 29b, which is placed near the opposing portions of the magnets 11 and 12 of the same polarity and wound around the center of the coil bobbin 25, is placed near the central axis P of the hollow portion of the magnets 11 and 12.

As shown in the completed side view of FIG. 5, the cartridge assembled as shown in FIG. It is inserted and fixed with adhesive. Thereby, the cantilever 13 and the needle tip 14 are arranged at a predetermined angle with respect to the horizontal direction.

Next, the operation of the cartridge constructed as described above will be explained with reference to the main part sectional view of FIG.

Empty parts 11a, 12a of magnets 11, 12
In this case, a magnetic flux 37 as shown in FIG. 7 is generated from the opposing portions of the magnets 11 and 12 of the same polarity, for example, from the N-pole surface to the S-pole of each. N pole and N
Almost all of the magnetic flux originally generated from the N-pole surface is concentrated from the boundary line with the pole and diverges in the direction perpendicular to the axis P, so a space with a high magnetic flux density more than 10 times the normally obtained magnetic flux density is created in the opposing part. It is formed near the. Since the coils 26a to 26c of the armature 15 are arranged in this high magnetic flux density space, when the coils 26a to 26d move using the wire portion 18a as a fulcrum in response to the movement of the needle tip 14 and the cantilever 13, each coil An extremely high voltage is induced depending on the moving speed and the number of interlinked magnetic fluxes. In addition, as mentioned above, the coil 26 of each channel
Since a, 26c, 26b, and 26d are wound in a figure 8 shape, each wire portion 29a of the figure 8 coil differentially cuts the magnetic flux in proportion to the movement of the needle tip 14 and thus the armature 15. The electromotive force is connected in series to generate electricity. That is, when the needle tip 14 moves, one side of the armature 15 retracts and the other side protrudes, but as a result, when the wire rod portion 29a of the coil retracts and when it protrudes, it is opposite. A current is generated in the direction of . However, since the coil is wound in a figure 8 pattern, the currents generated in opposite directions are aligned in the same direction within the coil wire 29 and are added together, resulting in the retracting part and the protruding part. The amount of power generated at the two locations is added together, resulting in twice the amount of power generated. Therefore, the movement of the needle tip 14 and the cantilever 13 can be efficiently linked to power generation, and even higher output voltage can be obtained.

In the above embodiment, the magnets 11, 12
A nonmagnetic or magnetic spacer may be interposed between the opposing portions. In this case, although the spatial magnetic flux density is reduced by the thickness of the spacer, the magnetic field distribution acting on the coil becomes uniform over a wider range, and the linearity of the output voltage with respect to the vibration amplitude of the coil improves. Further, in the above embodiment, the magnets 11,1
2 are connected using magnetic cases 32 and 33, but they may also be connected using adhesive or non-magnetic screws.

Further, since the magnetic system of the above-described embodiment is essentially an open loop, a magnetic path material can be inserted inside the armature coil to increase the output voltage and improve the frequency characteristics.

Effects of the Invention As described above, the present invention is configured such that the magnetic poles of a pair of magnets are closely opposed to each other, and power generation is performed in a high magnetic flux density space formed near the boundary surface, so that extremely high output voltage can be generated. A moving coil type cartridge can be obtained. In addition, since the magnetic flux generating part is a closed loop that does not constitute a closed magnetic path, there is no need for a magnetic path material (yoke), and the structure is simple, lightweight, and compact, and the shape and arrangement of the coil are free. It has a very high degree of advantage.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional moving coil type cartridge, FIG. 2 is an exploded perspective view of a moving coil type cartridge according to an embodiment of the present invention, FIG. 3 is a perspective view showing the appearance of the assembled state, and FIG. 4 5 is a side view of the cartridge in a completed state, FIG. 6 is a front view of the armature, and FIG. 7 is a sectional view of a main part in the axial direction showing a magnetic flux generation state. In addition, in the symbols used in the drawings, 11, 12...
Magnet, 13... Cantilever, 14... Needle tip,
15... Armature, 18... Tension wire,
24...Rubber damper, 25...Coil bobbin, 26a
~26d...Coil, 37...Magnetic flux.

Claims (1)

[Claims] 1 A pair of cylindrical magnets each having magnetic poles formed in the axial direction are arranged on the same axis with the magnetic poles of the same polarity closely facing each other, and a movable part having a coil on the central axis of the hollow part of the magnet. 1. A moving coil type cartridge, characterized in that a moving fulcrum is arranged so that a voltage is induced in the coil by a magnetic flux component generated from an opposing portion of the magnet in a direction orthogonal to the central axis.