JPS58146003A - Head shell - Google Patents

Abstract

PURPOSE:To increase rigidity of a head shell, and to prevent resonance, by melt-spraying a metallic oxide, a carbide, a boride, or boron, or a mixture of them, to a metallic base material. CONSTITUTION:As a metallic material, a magnesium alloy 1 is defatted and washed, and the blast-treatment is executed by polishing powder. Subsequently, by alumina and titanium powder containing boron carbide having 10-40mum particle diameter, a film 2 is formed to thickness of 0.1-0.5mm. by use of a plasma jet device. By constituting in this way, the modulus of specific rigidity and internal loss increase, and the resonance can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a head shell material that is lightweight, rigid, and has a large internal loss and is used for mounting a pickup in order to prevent abnormal resonance caused by the head shell during pickup playback.

Generally, a pickup consists of a cartridge equipped with a playback stylus for tracing the sound grooves on a record, and a head shell for connecting the cartridge to a tone arm to detect signals from the record.

Since the low resonant frequency during playback by a pickup is greatly affected by the weight of the headshell and tonearm, especially the headshell that is closest to the playback needle, a material that is lightweight, has high rigidity, and has high internal loss is desired.

Resonance with a reproduction frequency of 20H2 or less is often overlooked because it is outside the audible band, but it is modulated by the resonance of the head shell or tone arm excited by vibrations of several H2 or less due to warpage or eccentricity of the record. This may cause noise.

In addition, in order to avoid the overlap between the vibration noise around 25H2 caused by the turntenipple motor and the above-mentioned low-frequency resonance frequency, it is desirable to set this resonance frequency to 10 to 15H2. It is necessary to use L.

However, if the head shell is made lighter, its mechanical strength and rigidity decrease, which causes the head shell itself to resonate abnormally and deteriorate sound quality.

In order to reduce such abnormal resonance, it is possible to choose a material with high mechanical strength and rigidity, but this increases the weight of the radial shell and lowers the low-frequency resonance frequency to below 10H2, causing the record to become stiff. and the number H2 due to eccentricity
The first resonance induced by the following vibrations produces a large amplitude at the needle tip,
Level fluctuations, wow, etc. will occur.

To solve these problems, head shells have been developed using materials that are highly rigid and lightweight.

An example of this is a magnesium alloy. This alloy has a high specific stiffness among light metals, but has the disadvantage of a large resonance peak because of its low internal loss.

The present invention aims to eliminate such drawbacks by using aluminum,
By thermally spraying alumina, titania, boron, titanium polide, aluminum polide, boron carbide, etc., or a mixture of these onto the head cell base material of magnesium or these alloys, it has greater rigidity than the base metal and has less internal loss. It provides a great shell material. For thermal spraying, a flame spraying machine, a plasma spraying machine, a plasma spraying machine, etc. are used to spray ceramics, metals, carbides, borides, etc. on the surface of metals etc. for the purpose of insulation, corrosion resistance, and wear resistance.

Next, one embodiment of the present invention will be described.

First, a magnesium alloy as a metal base material is degreased and cleaned.
, perform blasting with abrasive powder, then form a film of boron carbide-containing alumina, chikunya powder c (particle size 1θ to 40μ) to a thickness of 0.1 to 0.5 mm using a plastic majet arm. and polish as necessary.

1st! ! ! These are the characteristic values of the material prepared according to the above example, and both the specific rigidity and internal loss are superior to magnesium alloys.

In addition to this example, titanium carbide and titanium boride were used.

Adding alumina thermal spray powder containing boron or the like also has the effect of increasing specificity and internal loss.

As explained above, if the material of the present invention, which is thermally sprayed with metals [binide, carbide, or boride], is used for the head shell, it is possible to obtain an excellent head 7L with less abnormal resonance due to its large rigidity and lightweight internal loss. can.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention. 1 is a Herad cell base material, and 2 is a thermal spray material. Applicant Nippon Columbia Co., Ltd. Figure 1

Claims (1)

[Claims] A head shell characterized in that a metal oxide, carbide, boride, boron, or a mixture thereof is thermally sprayed onto a metal base material.