JP2543159Y2 - Bearing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device having a dynamic pressure bearing.

[0002]

2. Description of the Related Art In a bearing device such as a dynamic pressure bearing having a plurality of bearing portions, the coaxiality of the inner and outer diameters of each bearing portion and the alignment of the plurality of bearing portions greatly affect bearing performance.
If there is misalignment at the time of assembling the bearing, the performance will be extremely poor. Therefore, in order to obtain good bearing performance, it is necessary to make the processing accuracy of the bearing part extremely high, which raises a problem of increasing the price of the bearing device.

Therefore, as a bearing device which solves this problem, there is a dynamic pressure bearing shown in FIG. In this dynamic pressure bearing, the coaxiality and alignment of the plurality of bearing portions can be easily ensured by integrally molding the plurality of bearing portions 32 and 35 into one sleeve 31. By the way, this dynamic pressure bearing includes the bearing portions 32 and 35 and the bearing portions 32 and 3.
5 is extremely narrow, it is necessary to reduce the friction torque of the grease between the sleeve 31 and the shaft.
A concave portion 33 is formed in a central portion of the inner peripheral surface other than the bearing portion to increase a distance between the central portion and the shaft. However, there is a problem that it is difficult to form a recess at the center of the inner peripheral surface of the sleeve 31.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a bearing device which can ensure good coaxiality and alignment of a bearing portion without requiring high-precision processing or difficult processing. .

[0005]

In order to achieve the above object, a bearing device according to the present invention is made of a first material, a bearing sleeve for supporting a shaft, and a second material. And a mounting sleeve having a projection on the inner periphery for supporting the bearing sleeve so that the bearing sleeve can be aligned. A dynamic pressure generating groove is provided on the inner periphery of the bearing sleeve.

[0006]

According to the above construction, the bearing sleeve supporting the shaft is supported so as to be centerable by the projection of the mounting sleeve disposed outside the bearing sleeve. Therefore, the bearing sleeve ensures good coaxiality and alignment with respect to the shaft without requiring high-precision processing or difficult processing due to the alignment of the protrusions.

[0007] If a resin material having good wear resistance and low friction is selected as the first material forming the bearing sleeve, the life of the bearing sleeve can be improved.

Further, if a suitably hard resin material suitable for alignment is selected as the second material forming the mounting sleeve, the mounting sleeve can perform optimal alignment with respect to the bearing sleeve.

Further, since the dynamic pressure generating groove is provided on the inner periphery of the bearing sleeve, the coaxiality and alignment can be easily performed without requiring high precision processing or difficult processing, especially for a dynamic pressure bearing having a small clearance. Can be secured.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments.

FIG. 1A shows a longitudinal section of a device in which the dynamic pressure bearings U and D of one embodiment of the bearing device of the present invention are press-fitted into a case 7. The dynamic pressure bearings U and D have exactly the same structure.
The dynamic pressure bearings U and D are provided with a bearing sleeve 2 having a dynamic pressure groove 2a on the inner peripheral surface and a bearing sleeve 6 having a dynamic pressure groove 6a on the inner peripheral surface to support the shaft 3.
The life of the bearing sleeves 2, 6 can be improved by using a resin material having good wear resistance and low friction as the material of the bearing sleeves 2, 6.

FIG. 1B shows a cross section near the bearing sleeve 2 of the dynamic pressure bearing U. FIG. 2 shows the dynamic pressure bearing U
1 shows a vertical cross section of FIG. Outside the bearing sleeve 2 of the dynamic pressure bearing U, a mounting sleeve 1 composed of two semi-cylindrical parts 1a and 1b is arranged. And this mounting sleeve 1
The groove 2 formed on the outer peripheral surface of the bearing sleeve 2
Alignment ribs 10a and 10b are formed as projections that are fitted to b and support the bearing sleeve 2 in an alignable manner. A mounting sleeve 5 composed of two semi-cylindrical parts 5a and 5b is arranged outside the bearing sleeve 6 shown in FIG. And, on the inner peripheral surface of the mounting sleeve 5,
By fitting into a groove 6b formed on the outer peripheral surface of the bearing sleeve 6,
Alignment ribs 50a, 5 for supporting the bearing sleeve 6 in an alignable manner
0b is formed. As the material of the mounting sleeves 1 and 5, a suitably hard resin material suitable for alignment is used so that optimum alignment can be obtained. The mounting sleeves 1 and 5 are fixed inside the case 7.

The bearing sleeve 2 of the dynamic pressure bearings U and D
And 6 are centerably supported by mounting sleeves 1 and 5 having centering ribs 10a, 10b and 50a, 50b, so that the center axes of the bearing sleeves 2 and 6 coincide with the center axis of the shaft 3. Is fine-tuned. Therefore, the coaxiality of the bearing sleeves 2 and 6 with respect to the shaft 3 and the alignment of the bearing sleeves 2 and 6 can be ensured without particularly requiring high-precision processing.

Further, since the mounting sleeves 1, 5 and the bearing sleeves 2, 6 are provided separately from the case 7, machining of the inner peripheral surface of the case 7 is easy. Therefore, the distance between the central portion of the inner peripheral surface of the case 7 that does not generate dynamic pressure and the shaft 3 depends on the bearing sleeves 2 and 6 that generate dynamic pressure and the shaft 3.
Case 7 so that it is larger than the extremely narrow distance between
It is easy to machine the center part of the inner peripheral surface of the above. Therefore, the friction torque between the case 7 and the shaft 3 can be easily reduced without the need for difficult processing.

In the dynamic pressure bearings U and D of the present embodiment, the mounting sleeves 1 and 5 are each composed of two semi-cylindrical parts, but the mounting sleeves are cylindrical as shown in FIG. One of the components 100 may be provided, and three alignment protrusions 100a may be provided at equal intervals on the inner peripheral surface of the component 100. Further, in the present embodiment, the bearing device is a dynamic pressure bearing, but the present invention can be applied to a sliding bearing.

[0016]

As is apparent from the above description, in the bearing device of the present invention, the projection of the mounting sleeve disposed outside the bearing sleeve supports the bearing sleeve for supporting the shaft so as to be centerable. It is. Therefore, the bearing sleeve is aligned so that its center axis coincides with the center axis of the shaft, and the coaxiality and alignment with the shaft can be improved without performing high-precision processing on the bearing sleeve.

Further, since a dynamic pressure generating groove is provided on the inner periphery of the bearing sleeve, conventionally, the clearance is extremely small, and therefore, a dynamic pressure bearing which required particularly high precision machining for improving the coaxiality and the alignment with high accuracy was conventionally required. Therefore, the necessity of high-precision machining can be eliminated, and the coaxiality and alignment with respect to the axis can be easily obtained with high accuracy.

[Brief description of the drawings]

FIG. 1 is a sectional view of an apparatus having an embodiment of the bearing device of the present invention.

FIG. 2 is a sectional view of the embodiment.

FIG. 3 is a sectional view of a conventional bearing device.

[Description of reference symbols] U, D hydrodynamic bearings 1, 5, 100 Mounting sleeve 2, 6 Bearing sleeve 3 Shaft 7 Case 10a, 10b, 50a, 50b Alignment rib 31 Sleeve 32, 35 Bearing part 33 Recess

Claims (1)

(57) [Scope of request for utility model registration] 1. A bearing sleeve made of a first material and supporting a shaft, and a projection made of a second material and arranged outside the bearing sleeve and supporting the bearing sleeve on its inner periphery so as to be centerable. A bearing device comprising: a mounting sleeve having: a dynamic pressure generating groove provided on an inner periphery of the bearing sleeve.