JPS5989823A - Fluid bearing device - Google Patents

Abstract

PURPOSE:To attain stable rotating characteristic by coating the surface of a bearing portion with ultra-hard composite material to improve wear-resisting property of the bearing portion and to maintain a groove structure for a long period of time. CONSTITUTION:In a bearing apparatus comprising a fixed unit and a rotating uit, a material having good cutting workability such as Al, Bs and so on is used. Several mu of an ultra-hard composite material such as titanium carbon TiCHv=2,000-3,000, tungstic carbon WcHv=2,000 and so on are applied to surfaces A, B of a fixed shaft 1 and a disc 3 by ion plating. In this arrangement, grooves 6A, 6B, 7 are kept from abrasion to attain stable rotating characteristic.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a hydrodynamic bearing device.

Conventional configuration and its problems The structure of a conventional hydrodynamic bearing will be explained based on FIG.

FIG. 1 shows a VTR (video tape recorder, hereinafter abbreviated as VTR) cylinder to which a hydrodynamic bearing device is applied.

A fixed shaft 1 is press-fitted into the center of the lower cylinder 2, a disk 3 is rotatably inserted into the fixed shaft 1, and a thrust receiver 4 and an upper cylinder 6 magnetic head 9 are attached to the upper part of the disk 3. and constitutes the rotation side unit.

Then, silica groups eA and eB are etched at 102 locations on the fixed shaft, and the fixed shaft 1
The tip surface 8 of the thrust receiver 4 is flat and precisely machined at right angles, and a single row of spiral groups 7 as shown in FIG. Processed with tings. Lubricating oil is applied to each of the three group parts, and when the rotating unit is rotated, pressure is generated by the pumping action of the three group parts, and the oil and film form completely. It appears to float and rotate.

However, in conventional examples, materials such as fixed shafts and disks that are bearing parts are made of aluminum, brass, stainless steel, etc. in order to reduce weight, prevent corrosion, and prevent corrosion. Due to wear caused by slight contact between the disk and the fixed shaft, sudden vibration during rotation, and surface scratches caused by external force from the drop tube, etc.
When used as a high-precision hydrodynamic bearing, stable characteristics such as uneven rotation cannot be obtained, and in the worst case, the bearing may seize and become unable to rotate. In particular, this is because, as shown in Figure 3, the viscosity of the lubricating oil used changes with temperature, and the viscosity decreases at high temperatures, making it easy to rub, which becomes a problem, especially when lubricating oil is used.

Purpose of the Invention In view of the above drawbacks, the present invention uses materials with good machinability such as AM and Bs, improves the wear resistance of the bearing part, maintains the group structure for a long period of time, and achieves stable rotational characteristics. The present invention aims to provide a hydrodynamic bearing device that achieves the following.

Structure of the Invention The present invention is a rotary drive bearing device using a direct drive motor, and the surface of the fixed shaft and disk is coated with ultra-hard composite material, such as titanium carbide, by ion blasting.
Tic Hy = 2000-3000, tungsten carbon WcHy = 2000, etc. are applied several μ,
This has the effect of preventing group wear and providing stable rotational characteristics.

DESCRIPTION OF EMBODIMENTS Below, embodiments of the present invention will be described with reference to the drawings. Figures 4 and 6 show a disk made of Bs material and a fixed shaft made of stainless steel.In the present invention f, after finishing each part with high accuracy by machining, the respective surface parts A, B was coated with 2-3μ of TiC.

Ion blasting of TiC 1 Pre-treatment Ultrasonic cold liquid cleaning and steam cleaning with perclean 2 ・Ion plating 0 Vacuum degree Introducing acetylene gas 5X10
Torr O evaporation source T1 was heated with electron beam 0 Evaporation speed 0.3 f/min, (coating time 20 min) 0 Substrate applied voltage 3 KV Incorporating the Tic coated disk and the fixed shaft under the conditions of -video cylinder The results of the life test are shown below.

Effects of the Invention As described above, the present invention maintains the shape of the group for a long time by coating the surface of the bearing part with a few microns of ultra-hard composite material such as TiC, thereby making it possible to create a video cylinder, and its practical effects can be seen to be great.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional hydrodynamic bearing device, Figure 2 is a diagram showing the shape of a spiral group, Figure 3 is a viscosity diagram of lubricating oil used in an embodiment of the invention, and Figure 4 is a diagram of the invention. FIG. 6 is a cross-sectional view of the disk in one embodiment, and FIG. 6 is a cross-sectional view of the fixed shaft. 1... Fixed shaft, 2... Lower cylinder, 3... Disc, 4... Thrust receiver, 6... Upper cylinder, eA, eB...
...Radial group. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure f Figure 2 Figure 3 Benefits (“0”) Figure 4

Claims (1)

[Scope of Claims] 0) Consists of a fixed side unit that is rotationally driven by a direct drive motor and a rotatable rotating side unit, and is provided between the fixed side unit and the rotating side unit, and is connected to a bearing via a fluid. A hydrodynamic bearing device in which the surface of the bearing part is coated with an ultra-hard composite material. (2) The hydrodynamic bearing device according to claim 1, wherein the ultra-hard composite material is titanium carbon or tungsten carbon.