JPS5823302A - Pickup tone arm - Google Patents

Abstract

PURPOSE:To suppress the resonance at low frequencies for a tone arm, by supporting a mass via a viscoelastic body on a supporting bearing of the tone arm and inserting a viscous resistor between the tone arm and a fixed part. CONSTITUTION:A stabilizer 6 is supported on a bearing 7 of a tone arm 3 via a viscoelastic body 4, and a viscous fluid 11 is filled between a cup 10 and the bearing 7. Thus, the resonance at low frequencies can be suppressed and the response at the resonance frequency can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pickup scene arm, in particular, a 20th mass is dynamically excited through a viscoelastic body on a bearing fulcrum, and the pickup scene arm is largely displaced at a period of fts. , which does not significantly affect the playback sound quality. In order to damp such resonance, oil damping methods, as shown in the equivalent circuit shown in FIG. The equivalent circuit for the above oil damping method and dynamometer damping method only covers the low range, and the high range is omitted. R is the mechanical impedance seen from the stylus tip, and vr is the velocity amplitude of the record sound groove. ,09%
RP is the equivalent ampliance and equivalent resistance in the resonator of the cartridge.

(hereinafter referred to as CT's RP)
R1 is the isometric mass as seen from the tip of the tonearm O needle including the dead weight of the ridge, and R1 is the isometric resistance at the fulcrum of the bearing, hb
This is the viscous resistance in the Styl damping effect. (Hereinafter referred to as Rt 0) Figure 3 Mtl and Mtl are the equivalent mass of the main body of the tone arm and the equivalent mass of the vibration absorbing part, respectively 0 (Hereafter referred to as Mtl Mtl.) Cd, the arm is M
This is the equivalent compliance and equivalent resistance of a damper that combines tl and mt. (Hereinafter, it will be referred to as C turtle property.) In this case, Rt becomes a small amount that can be almost ignored.

Of the equivalent circuits shown in Figures 2 and 3 above, in the oil damping method, as shown in Figure 94, as the turning effect is increased, the response in the ultra-low range below 10 points increases. >, rather, it is not practical in combination with recent high compliance type cartridges. In addition, in the dynamic damping method, the effect is difficult to be seen unless the mass of Ml rich with respect to Mtl in Fig. 3 is increased, and it is affected by external vibration etc. 1 (problems). In order to solve these problems, a book is known in which a second mass 6 is supported on a bearing fulcrum via a viscoelastic body 4, as shown in FIG. Equivalently, this structure can be represented by a mass 6 of Mt, a viscoelastic body 4 of equivalent compliance cd and equivalent resistance Rdt, and an equivalent circuit similar to that shown in FIG. Dud wAFi This is a book that provides a pickup tone arm with the structure shown in Figure S above, which has improved damping characteristics, and its feature is that a viscoelastic material is interposed between the tone arm body and the fixed part. It's from the ton. Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 6 to 8.

The equivalent circuit of the present invention is as shown in figure fa6, and in the equivalent circuit of the dynasec dumbinder method in figure 3,
It is a type Kl & one with R4 Goose added.

FIG. 7 shows the changes in the low-frequency resonance characteristics when Mtt, Mtm, tp and Cd, RdO are kept constant and Ml is varied. However, the low-frequency characteristics of a general tonearm are not damped at all, and (b) is the third
This figure shows the case where the dynamometer damping is multiplied by an appropriate K. In this case, if the Rdl() constant is not appropriate, it will not become a single-resonant pattern like the one shown in Figure 2. It becomes a two-resonant type. In the present invention, it has been found that by appropriately setting the value of Rdl as described above and adding 1 extra layer to the top of the circle, it is possible to create a pattern with suppressed resonance peaks like k(e). Shimaru.

Next, a specific structural example according to the present invention is shown in FIG.

2 is the car installed at the tip of the tone arm) 17 The main body of the tonearm, and 1 is the cantilever. An arm pipe connects the three-piece cartridge 2 and the bearing body 7, and a weight 5 is fitted behind the arm pipe. Reference numeral 9 denotes a bearing rotating portion of the tone arm body, and the tone arm is supported by a base 80. o) The tone arm is supported at one point on the vertical axis of the bearing body portion 7 of the tone arm 3 via a viscous body or a viscoelastic body 4. The second mass of the stabilizer 6, that is, the mass of the scissors is Mt! in FIG. The viscous body or viscoelastic body 4 constitutes an equivalent compliance Cd and an equivalent resistance Rdt. The second mass 6 is statically balanced, and a part of the bearing main body 7 of the arm pipe (3) is grounded via a viscous body R. In this case, the viscous body 11 is 6th
The superior circuit BA shown in the figure! 010, which corresponds to , is a cup that stores the viscous fluid 11, and is fixed to the arm board side.

Oil cup 10 can be attached to pace 8 or separately at any desired position.
It is clear that the arm or the arm bearing body (7) and part of the arm bearing body (7) and the fixing part 14 should be interposed with the viscous fluid 11 so that they are equally grounded. It is.

Since the present invention is configured and operates as described above, it is possible to obtain a Daikei damping effect compared to the conventional damping method, so that the vibration of the tone arm at 10 points can be reduced, so stable operation is expected. In addition, the increase in response of 10 points or less is only slightly smaller than that of the oil damping method, so it is excellent in tracking warping of records. Furthermore, in the present invention, by adding Rt14, it is possible to set the mass of mtt to be small, increasing the degree of freedom in design.

[Brief explanation of the drawing]

Fig. 1 is a characteristic diagram showing an example of the general frequency characteristics of the bass range of a pickup, Fig. 2 is an equivalent circuit of a conventional oil damping tone arm, and Fig. 3 is an equivalent circuit of a conventional dynamic damping tone arm. FIG. 4 is a characteristic diagram in the vicinity of fo for explaining the damping effect due to bearing resistance Rt, FIG. 1 is a schematic diagram of a dyna-building damping type tone arm to provide the theory of the present invention, and FIG. FIG. 7 is a characteristic diagram near fo showing the damping characteristics of the present invention, and sN is a plan view and steel side view of an embodiment of the pickup tone arm of the present invention. In the figure, 1 is a cantilever, 2 is a cartridge body, 3 is an arm pipe, 4 is a viscoelastic body, the vessel is a weight, and 6 is a second
, 7 is the bearing body, 8 is the base, 10 is the ★ knob,
11Fi viscous material. Patent applicant Kazumi Yamaguchi, agent and patent attorney for Nippon Koshinbia Co., Ltd.

Claims (1)

[Claims] A pickup tone arm 0 having a structure in which a 20th mass is supported on a bearing fulcrum via a viscoelastic body, and a viscous resistance body is interposed between the tone arm main body and a fixed part.