JPH06325389A - Sliding member for optical pickup - Google Patents

Abstract

PURPOSE:To provide a sliding member for an optical pickup capable of utilizing insert molding advantageous to production, hard to scratch at the time of molding and capable of ensuring sliding property. CONSTITUTION:This sliding member for an optical pickup insert-molded together with an actuator in one body slides an object lens holding member so as to allow an object lens to follow the movement of an optical disk. Nickel- phosphorus plating contg. dispersed polytetrafluoroethylene (PTFE) is formed on the sliding face of a shaft member 10 supporting a lens holder 2. Since a surface layer made of the nickel-phosphorus plating contg. dispersed PTFE is based on nickel, it is harder than the conventional PTFE coating and is hard to scratch at the time of insert molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a sliding member for an optical pickup used in an optical disk device or a magneto-optical disk device.

[0002]

2. Description of the Related Art FIG. 3 shows a shaft sliding type actuator portion of a conventional CD pickup device. In the figure, 1 is a shaft member, 2 is a lens holder for supporting an objective lens (not shown), 3 is an outer yoke, 4 is an inner yoke, 5 is a tracking or focusing coil, and 6 is a magnet. After the base end portion of the shaft member 1 is press-fitted into the outer yoke 3, the tilt angle adjusting resin 7 is fixed.

[0003]

In the above CD pickup device, in order to follow the movement of the optical disc, the lens holder 2 that supports the objective lens is always servoed and the position is corrected in the focus or track direction. Therefore, the shaft member 1 is required to have high slidability and high accuracy, and generally, a stainless steel material coated with PTFE (polytetrafluoroethylene) having excellent lubricity and wear resistance is used.

Conventionally, as a means for assembling the shaft member, a means for press-fitting into the yoke is generally taken. However, the press-fitting means has a drawback that the number of steps is large, such as press-fitting the shaft and fixing the adhesive resin to the yoke. Insert molding means has been considered as a means for solving this drawback. Therefore, the sliding surface of the sliding member (eg shaft member) is PT
FE coating is applied, and although high slidability can be obtained,
PTFE is very soft (Shore hardness: 50-6)
5) Therefore, during insert molding, the shaft member surface often comes into contact with other members due to the positional accuracy of the shaft, etc.
The shaft member is easily damaged by FE coating, and as a result, the characteristics of the actuator are deteriorated.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sliding member for an optical pickup, which is capable of utilizing insert molding which is advantageous in manufacturing and which can ensure slidability.

[0006]

SUMMARY OF THE INVENTION According to the present invention, in order to make an objective lens follow the movement of an optical disc, a holding member for holding the objective lens slides, and a slide for an optical pickup integrally insert-molded with an actuator section. It is a moving member, and the gist is that the sliding surface is plated with nickel-phosphorus in which PTFE is dispersed. The plating material is PT
Those containing 20 to 30% by volume of FE are preferable, and the electroless plating method is applied as the plating method.

[0007]

According to the above construction, since the PTFE-dispersed nickel-phosphorus plating applied to the surface layer of the sliding member is based on nickel, it is considerably harder than the PTFE coating, and is scratched during insert molding. It is difficult, and there is no fear that the characteristics of the actuator will be degraded.

[0008]

FIG. 1 shows an actuator section of an optical pickup device according to an embodiment of the present invention. The same or similar members as those in FIG. 2 are designated by the same reference numerals. Figure 1
In the figure, 10 is a shaft member, the sliding surface of which is PTFE
Nickel-phosphorus plating is dispersed. The shaft member 10 is insert-molded through a resin 11 and fixed integrally with the outer yoke 3 and the inner yoke 4.

FIG. 2 shows a surface treatment step of applying PTFE-dispersed nickel-phosphorus plating to the shaft member 10. First, the surface of the sliding member (shaft member) is washed by the steps of washing with water, pickling and washing with water, and then electroless Ni-P plating is performed. This is to improve the adhesion of the next Ni-P-PTFE plating.

Next, a plating material (about 90 ° C., pH 5 to 5) obtained by mixing the above-mentioned plated sliding member with nickel hypophosphite solution (Ni-P) by mixing PTFE as a dispersant.
5.5), and electroless Ni-P-PTFE plating is performed. PTF having lubricity in this electroless plating process
An E-dispersed composite plating coating (2-3 μm) is obtained.

The sliding member obtained by the above surface treatment step has a friction coefficient almost equal to that of the conventional PTFE paint coating. Moreover, since the plating layer is made of nickel as a base, it is considerably harder than the PTFE coating (Vickers hardness: 300), and is not easily scratched during insert molding.

Further, the heat treatment (350 ° C.) increases the hardness (Vickers hardness: 600), and the effect of the plating layer can be further improved.

Further, since the electroless plating treatment can control the thickness of the film to be coated and control the variation of the outer diameter of the shaft and the surface roughness, the post-processing is unnecessary.
Therefore, the surface treatment cost can be significantly reduced.

In addition, the PTFE dispersion composite plating similar to the above is applied to the shaft insertion inner peripheral portion of the holder of the mating member, so that the slidability can be further improved.

[0015]

As described above in detail, when the present invention is applied, insert molding, which is advantageous in manufacturing, can be used, and scratches are less likely to occur during molding, and slidability can be ensured. Can be obtained.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a cross-sectional view of an actuator portion including a sliding member for an optical pickup.

FIG. 2 is a surface treatment step diagram for obtaining a sliding member for an optical pickup.

FIG. 3 is a cross-sectional view of an actuator unit including a conventional sliding member for an optical pickup.

[Explanation of symbols]

 1 Shaft Member 2 Lens Holder 3 Outer Yoke 4 Inner Yoke 5 Tracking Coil 6 Magnet 7 Fixing Resin 10 Shaft Member 11 Fixing Resin

Claims (1)

[Claims] 1. A sliding member for an optical pickup, wherein a holding member for holding the objective lens slides in order to make the objective lens follow the movement of an optical disk and is insert-molded integrally with an actuator section. A sliding member for an optical pickup, the surface of which is plated with nickel-phosphorus in which polytetrafluoroethylene is dispersed.