JPH1037948A - Bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it advantageous to swing accuracy by securing a bearing span long even in the same bearing length in a thin type motor. SOLUTION: A fixed shaft 1 having a cylinder surface-shaped outer peripheral part, a rotor side sleeve bearing 2 which is formed in an almost cylindrical shape and is fitted around the fixed shaft 1, a rotor side bearing house 3 fitted around the sleeve bearing 2 and an oil seal part 4 are provided. In this case, a dynamic pressure groove 5 in the shape of pushing out fluid between the fixed shaft 1 and the sleeve bearing 2 to the outside of both end surfaces of the sleeve bearing 2 when the sleeve bearing 2 rotates, is executed on an inside diameter surface of the fixed shaft 1 and the sleeve bearing 2, and a dynamic pressure groove 6 in the shape of sucking fluid of an upper sealed space and a lower sealed space sealed by the rotor side bearing house 3, the fixed shaft 1 and the oil seal part 4 in both end surfaces of the sleeve bearing 2 when the sleeve bearing 2 rotates, is executed on both end surfaces of the sleeve bearing 2, and these are constituted so that maximum pressure is applied to both end inside diameter surfaces of the sleeve bearing 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a motor market in which a reduction in thickness is required. In the market of a motor, it is necessary to make the bearing span as long as possible by using a sleeve bearing so that the runout accuracy is improved more than that of a thick motor. It relates to a bearing configuration.

[0002]

2. Description of the Related Art Conventionally, a dynamic pressure journal bearing of the type having a herringbone groove has been generally used. FIG. 2 shows a configuration diagram of a conventional general dynamic pressure journal bearing. Briefly described below, in FIG.
Reference numeral 11 denotes a fixed shaft, 12 denotes a sleeve bearing, 13 denotes a bearing house, 14 denotes an oil seal, and 15 denotes a herringbone dynamic pressure groove provided on the outer periphery of the fixed shaft 11. Here, when the sleeve bearing 12 serving as the rotor rotates, the fixed shaft 11 and the sleeve bearing 12 are rotated by a herringbone dynamic pressure groove 15 provided on the outer periphery of the fixed shaft 11.
A high-pressure part is generated in the gap between the two and can be supported with low friction.

[0003] However, the herringbone groove needs two-way grooves in order to concentrate the fluid and apply pressure to a part of the herringbone groove. The need for grooves reduces the bearing span.
Further, in the case of a thin motor, a high-precision machining technique for reducing a clearance between a shaft and a bearing is required in order to produce a desired pressure with a short groove length.

The present invention has been made in view of the above-described problems in the prior art, and has as its object to provide a thin motor having a long bearing span even with the same bearing length. Accordingly, it is an object of the present invention to provide a bearing device that is advantageous with respect to runout accuracy.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. A bearing device according to the present invention comprises a fixed shaft 1 having a cylindrical outer peripheral portion and a substantially cylindrical shape. A rotor-side sleeve bearing 2 externally fitted to the fixed shaft 1, a rotor-side bearing house 3 and an oil seal portion 4 externally fitted to the sleeve bearing 2 are provided. When the sleeve bearing 2 rotates, the fixed shaft 1
A dynamic pressure groove 5 is formed which pushes out the fluid between the sleeve bearing 2 and both ends of the sleeve bearing 2, and the both ends of the sleeve bearing 2 are fixed to the rotor-side bearing house 3 when the sleeve bearing 2 rotates. A dynamic pressure groove 6 is formed to suck fluid in the upper sealed space and the lower sealed space sealed by the shaft 1 and the oil seal portion 4 into both end surfaces of the sleeve bearing 2. It is configured to apply the maximum pressure.

[0006]

According to the bearing device of the present invention having such means,
Since the maximum pressure is applied to the inner diameter surfaces at both ends of the sleeve bearing 2, the shaft support span can be made as long as the shaft length, so that the runout accuracy is improved and the motor can be made thinner.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a motor bearing device according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view showing a bearing device according to an embodiment of the present invention, which is used, for example, for a small and thin motor. In FIG. 1, 1 is a fixed shaft, 2 is a sleeve bearing, 3 is a bearing house,
4 is an oil seal portion, 5 is a dynamic pressure groove provided on the outer periphery of the fixed shaft 1, and 6 is a dynamic pressure groove provided on both end surfaces of the sleeve bearing 2.

A bearing device according to a first embodiment of the present invention includes a fixed shaft 1 having a cylindrical outer peripheral portion, a rotor-side sleeve bearing 2 formed substantially in a cylindrical shape, and externally fitted to the fixed shaft 1. And a rotor-side bearing house 3 fitted externally to the sleeve bearing 2 and an oil seal portion 4.

On the inner surface of the fixed shaft 1 and the sleeve bearing 2, there is formed a dynamic pressure groove 5 having a shape for extruding fluid between the fixed shaft 1 and the sleeve bearing 2 out of both end surfaces of the sleeve bearing 2 when the sleeve bearing 2 rotates. When the sleeve bearing 2 rotates, the fluid in the upper sealed space and the lower sealed space sealed by the rotor-side bearing house 3, the fixed shaft 1, and the oil seal portion 4 is applied to both end surfaces of the sleeve bearing 2. 2 are provided with dynamic pressure grooves 6 shaped to suck into both end faces.

As a result, when the rotor rotates, a maximum pressure is applied to the inner diameter surfaces of both ends of the sleeve bearing 2 and the bearing is supported at these two places. Therefore, the shaft support span can be made as long as the shaft length, and the same length can be obtained. The runout accuracy is improved over the conventional bearing.

Although the embodiment of the bearing device according to the present invention has been described above, the design can be changed or modified freely without departing from the gist of the present invention.

[0012]

Since the bearing device of the present invention has the above-described structure, the following effects can be obtained. That is, according to the bearing device of the present invention, the shaft support span can be made as long as the shaft length, so that the running accuracy is improved and a thin bearing device that is advantageous for the running accuracy can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a bearing device according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a bearing device according to a conventional example.

[Description of Signs] 1 Fixed shaft 2 Sleeve bearing 3 Bearing house 4 Oil seal part 5, 6 Dynamic pressure groove

Claims (1)

[Claims] 1. A fixed shaft having a cylindrical outer peripheral portion, a rotor-side sleeve bearing formed substantially in a cylindrical shape and externally fitted to the fixed shaft, and a rotor-side bearing house externally fitted to the sleeve bearing. A dynamic pressure groove having an oil seal portion and having a shape in which the fluid between the fixed shaft and the sleeve bearing is pushed out of both end faces of the sleeve bearing when the sleeve bearing rotates, on the fixed shaft and the inner diameter surface of the sleeve bearing; And, when the sleeve bearing rotates, the fluid in the upper sealed space and the lower sealed space sealed by the rotor-side bearing house, the fixed shaft, and the oil seal member is provided on both end surfaces of the sleeve bearing. A bearing device wherein a dynamic pressure groove having a shape for sucking into both end surfaces of a sleeve bearing is provided, and a maximum pressure is applied to both inner diameter surfaces of the sleeve bearing.