Dynamic Bearing Device

Abstract

Disclosed is a dynamic bearing device which allows production of a smaller housing at low cost and which suppresses ion elution from the resin portion to thereby maintain cleanliness in the dynamic bearing device and exert a desired bearing performance. A dynamic bearing device 1 is equipped with a bearing sleeve 8 fixed to the inner periphery of the housing 7, and a rotary member rotatable relative to the bearing sleeve 8 and the housing 7, in which the rotary member is supported in the radial direction and the thrust direction in a non-contact manner by a dynamic pressure action of a lubricant fluid generated in a bearing clearance. The housing 7 is formed by injection molding of a resin composition containing polyphenylene sulfide (PPS) as the base resin and PAN type carbon fibers as a filler.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a dynamic bearing device. This dynamic bearing device are suitable as a bearing device for use in a spindle motor of an information apparatus, for example, a magnetic disc apparatus, such as an HDD, an optical disc apparatus, such as a CD-ROM, a CD-R / RW, or a DVD-ROM / RAM, or a magneto-optical disc apparatus, such as an MD or an MO, a polygon scanner motor for a laser beam printer (LBP), a color wheel for a projector, or a small motor for an electric apparatus, such as an axial flow fan.[0003]2. Description of the Related Art[0004]Apart from high rotational accuracy, an improvement in speed, a reduction in cost, a reduction in noise, a reduction in weight, etc. are required of the motors as mentioned above. One of the factors determining such requisite performances is the bearing supporting the spindle of the motor. Recently, as a bearing of this type, use of a dynamic bearing superior in...

AI Technical Summary

Benefits of technology

The present invention provides a housing for a dynamic bearing device that is more precise, lighter, and less expensive than previous versions. The housing is made of a resin composition containing polyphenylene sulfide (PPS) as the base resin, which has high oil resistance and low out gas properties. The resin composition also contains carbon fibers as a filler, which enhance the strength and dimensional stability of the housing. The carbon fibers have high conductivity, which helps to dissipate static electricity and maintain the bearing performance. The reinforcing effect and static electricity removing effect of the carbon fibers can be enhanced by adjusting their aspect ratio. The filling amount of carbon fibers should be between 10 to 35 vol % to ensure sufficient reinforcing and formability of the housing.

Problems solved by technology

At the same time, the requirement for a reduction in the cost of a dynamic bearing device is becoming increasingly severe.

Thus, there is a fear of a product generated through the reaction of the resin material forming the housing with the lubricating oil causing denaturing degeneration in the lubricating oil or a deterioration in the cleanliness of the bearing device.

In particular, in the case of a bearing device to be used in an apparatus for driving a recording disk, such as a hard disk, the out gas generated in the high temperature atmosphere causes a deterioration in the cleanliness of the bearing device or the recording disk driving apparatus, such as contamination of the surface of the hard disk.

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