JPS607602A - Pickup cartridge - Google Patents

Abstract

PURPOSE:To smooth reproducing characteristics in a wide range from a low voice range to a high voice range by using a dumper with cylindrical double construction consisting of an inside dumper made of synthetic rubber or the like having low viscous resistance and an outside dumper made of synthetic rubber or the like having high viscous resistance. CONSTITUTION:The dumper 5 has coaxial double construction consisting of the cylindrical inside dumper 5A made of synthetic rubber or the like having comparatively low viscous resistance and the cylindrical outside dumper 5B made of synthetic rubber or the like having comparatively high viscous resistance. The thickness of the inside dumper 5A is formed larger than that of the outside dumper 5B. Therefore, a prescribed compression stress is previously applied to the inside dumper 5A after the completion of assembling. The brake of the inside dumper 5A is applied to a high voice frequency band having a comparatively small deflection and the brake of the outside dumper 5B is applied to a low voice frequency band having a comparatively large deflection, so that smooth reproducing characteristics can be obtained in the wide range from the low frequency range to the high frequency range.

Description

[Detailed Description of the Invention] This invention relates to a pickup cartridge, and more specifically, a pickup that improves the damping characteristics of a mechanical vibration system including a cantilever so as to obtain flat characteristics from the low range to the middle and high ranges. This is about crab 1 to ritsuji.

It is generally well known that when a pickup cartridge plays back recorded sound, relatively prominent resonance peaks appear in the level and frequency characteristics on the low and high frequency sides. It has also been theoretically analyzed that the sharpness of this resonance peak is largely influenced by the equivalent mass of the tone arm including the Kerr 1 helis, the mechanical resistance of the vibration system, and the compliance of the dampers.

Based on these experiences and theoretical analyses, many attempts have been made to lower the Q value of the resonance peak by reducing the equivalent mass of the tone arm and increasing the mechanical resistance of its fulcrum, with some success. However, when it comes to cartridges, increasing the effective mechanical resistance makes it difficult for the cantilever to move, while increasing the compliance of the damper conversely makes its movement unstable, which will inevitably lead to poor trackability. Particularly on the low frequency side, solving these problems has attracted attention as it will lead to improvements in overall characteristics, including the tone arm.

This invention was made in view of the above points, and its purpose is to achieve flat reproduction from low to medium to high frequencies without sacrificing trackability by adopting a simple coaxial double structure damper. The object of the present invention is to provide a pickup cartridge that can obtain characteristics.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows an example of an electromagnetic pickup cartridge to which the present invention is applied.

In addition, only the knob member having the needle structure is shown in the figure, and this knob member is attached to the car 1-not shown.
It is designed to be removably attached to the ridge body. This knob member consists of a needle structure including a cantilever 1 and a knob 6 that supports this needle structure. A stylus 2 is attached to one end of the cantilever 1, and an armature support 3 made of, for example, synthetic resin is attached to the other end. In this embodiment, the support body 3 includes two magnetic poles made of, for example, rod-shaped permanent magnets arranged between pole pieces on the side of the cartridge body (not shown).
Two armatures 4, 4 are installed in a V-shape.

The cantilever 1 and support body 3 are vibably attached to a receiving surface 8 of a knob 6 via a damper 5.

Referring to FIG. 2, the cantilever 1 is made of a pipe material such as aluminum, and a suspension wire 7 made of, for example, piano wire is caulked to the end thereof. The support body 3 is formed by a molding method using a plastic material, for example, and at this time, one end of the armature 4 is also embedded at the same time and integrated. The damper 5 is passed through the suspension wire 7 through its center hole. In this invention, the damper 5, as illustrated in FIG. 3, is constructed in a coaxial double structure, consisting of a cylindrical inner damper 5A and an outer damper 5B made of, for example, synthetic rubber. In this case, the thickness of the inner damper 5A, that is, the length in the axial direction, is larger than that of the outer damper 5B.For example, when one surface of both dampers 5A, 5B is aligned, a step is created on the other surface. There is. A metal rod 9 is passed through the suspension wire 7 through its center hole and fixed by caulking or the like.

In this way, a needle assembly including the cantilever 1 was assembled, and the rod 9 was inserted into the attachment hole 10 formed in the knob 6, and an appropriate tension was applied to the suspension wire 7. Then tighten the rod 9 with the screw 11.
By tightening the knob 6, the knob 6 is attached to the receiving surface 8 of the knob 6 so as to be able to vibrate.

When the structure including the cantilever 1 is attached to the knob 6, the inner damper 5A will be compressed. The thickness dimension before compression is determined so that there is no difference in level from /<5B and the surface is almost the same surface. Therefore, in the assembled state, there is almost no compressive force applied to the outer damper 5B, so no accompanying stress is generated, but stress is generated in the inner damper 5A depending on the degree of compression. This stress is
When the vibration system resonates during record sound reproduction, it acts as a braking force, but its magnitude varies depending on the material of the bumper, so the above-mentioned step size is also appropriately set in consideration of these factors. In this embodiment, the inner damper 5A has a relatively small viscous resistance force, for example, and the outer damper 5B has a relatively small viscous resistance force of 1.
Synthetic rubber, which has relatively high viscous resistance, is used for this purpose. In this way, by appropriately selecting the material and dimensions of both dampers 5A and 5B, it is possible to maintain good high-frequency characteristics of record playback sound, and also provide sufficient damping force against resonance peaks on the low-frequency side. can be affected.

This braking force will be briefly explained with reference to FIG. In order to make the explanation easier to understand, the braking force is assumed to be substantially equal to the compressive stress, and is qualitatively indicated by the size of the arrow for convenience. Figure (a) shows the stress generation state when the vibration system is assembled, but as mentioned above, this stress occurs only in the inner damper 5A,
This hardly occurs in the outer damper 5B. FIG. 2B shows a state in which the cantilever 1 swings outward, for example, from the center of the turntable (not shown) during actual performance, and the support 3 is accordingly displaced as shown. In this case, even if the deflection angle is the same, the magnitude of the deflection is, for example, smaller as it is closer to the central axis around which the suspension wire 7 is stretched, and larger as it is farther from the central axis. Therefore, in the case of the inner damper 5A, the stress on the lower side of the suspension wire 7 shown in the figure increases somewhat, and the stress on the upper side decreases somewhat, but the stress of the inner damper 5A as a whole is equal to the stress in the case shown in (a). There is almost no change. However, in the outer damper 5B, due to the large amount of deviation and the use of a material with relatively high viscous resistance, a large compressive stress is generated in the lower part, and a large tensile stress is generated in the upper part. occurs. These stresses are
As shown by the arrow, the braking force is generated in the opposite direction to the deflection direction, that is, in the clockwise direction relative to the counterclockwise deflection, so that a sufficient braking force is exerted on the support body 3. Note that the above deviation amount is generally large on the low frequency side and small on the high frequency side. Therefore, the outer damper 5B exerts its braking effect mainly on the low frequency side, and on the high frequency side (where the amount of deviation is small), (a)
Since the state is close to that shown in FIG. 1, the outer damper 5B does not contribute to braking with a small amount of displacement. However, since compressive stress is applied to the inner damper 5A during assembly, it exhibits appropriate damping in the high range side where the amount of deviation is small.

FIG. 5 shows a damper 12 different from the damper 5 described above. This damper 12 has a coaxial two-layer structure consisting of an inner damper 12A and an outer damper 1.2B, and the materials used are the same as those of the inner dampers 5A and 5B of the damper 5, but the thickness The heights are the same and there are no steps. In Figures 6 and 7,
Two examples incorporating this damper 12 are shown.

That is, in FIG. 6, the shape of the support 13 is different from that of the support 3 shown in FIG.
, a circular convex portion 13A is provided on the side facing the damper 12.
is provided, and when assembling the vibration system, this convex portion 1
3A compresses the inner damper 12A to apply stress, and the same effect as in the case where the cartridge shown in FIG. 2 is constructed using the stepped damper 5 is obtained. On the other hand, in FIG. 7, a circular convex portion 18A is provided on the receiving surface 8 side of the knob 6.
A compressive stress is applied to the inner damper 12A.

As described above in detail, the pickup cars 1 to 2 according to the present invention have a cylindrical inner damper made of synthetic rubber or the like with relatively low viscous resistance, and a cylindrical inner damper made of synthetic rubber or the like with relatively large viscous resistance. It has a damper configured in two coaxial layers by combining an outer damper and an outer damper, and a predetermined compressive stress is applied to the inner damper in advance.

As a result, the damping force of the inner damper acts on the high audio frequency band with a relatively small amount of deviation, and the braking force of the outer damper acts on the low frequency band with a relatively large amount of deviation. Since it is divided into two parts, it maintains good 1-run power from high to low range, and also improves the low range characteristics of the reproduced sound by applying sufficient damping force especially to the resonance on the low range side. It can be improved.

Although the above description is based on the case where the present invention is applied to an electromagnetic pickup cartridge, it can also be applied to a contact type pickup cartridge, such as an electrodynamic type or a piezoelectric type, in which the sound groove of a record is traced with a stylus. It is.

[Brief explanation of the drawing]

The attached drawings all relate to embodiments of the present invention, and FIG. 1 is a perspective view of a knob member for an electromagnetic pickup cartridge to which the present invention is applied, and FIG. 2 is an internal structure diagram taken along the line XX in FIG. 1. , FIG. 3 is a cross-sectional view of the damper, and FIG. 4 is a diagram qualitatively showing the deflection of the damper and the thickness of the braking force.
FIG. 5 is a sectional view showing another modification of the damper, and FIGS. 6 and 7 are internal structural diagrams when the damper shown in FIG. 5 is applied. In the figure, 1 is a cantilever, 2 is a stylus, 3.13 is a support, 4 is an armature, 5 and 12 are dampers, 6 is a knob, and 7 is a suspension wire. Patent applicant: Audio-Technica Co., Ltd. Agent: Patent attorney: Takuya Ohara

Claims (1)

[Scope of Claims] (1) A needle groove body including a cantilever to which a stylus is attached at one end and an armature support at the other end, and the needle groove body is connected via a suspension wire extending from the support body side. In a pickup cartridge comprising a knob that is held so as to vibrate, and a damper disposed between the knob and the support, the damper is made of synthetic rubber or the like having relatively low viscous resistance, and A coaxial two-layer structure consisting of an inner damper having a through hole for passing the suspension wire through, and a cylindrical outer damper made of synthetic rubber or the like having relatively high viscous resistance and laminated around the inner damper. A pickup cartridge, wherein only the inner damper is compressed to a predetermined size when the needle groove body is attached to the knob with the suspension wire. (2. In claim (1), the pickup cartridge is characterized in that the axial length of the inner damper is longer than the axial length of the outer damper. (3) Claim (1) ), wherein either the support or the knob is provided with a protrusion that compresses the inner damper.