JP4164137B2 - Method for machining dynamic pressure generating groove of hydrodynamic bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is applied to a dynamic pressure bearing.
[0002]
[Prior art]
Conventionally, a dynamic pressure bearing is formed on the surface of one member of the stationary member and the rotating member that face each other, but the dynamic pressure generating groove in the dynamic pressure generating bearing may be formed by etching. Many. Therefore, as shown in FIG. 5, since the peripheral surface of the one member 50 is masked so that the hill portion 52 between the grooves 51 is not etched and only the groove 51 is etched, the groove bottom surface 53 has a subtle material component. The surface of the hill portion 52 between the grooves 51 remains as a smooth surface, that is, a mirror surface by masking.
[0003]
[Problems to be solved by the invention]
In the conventional dynamic pressure generating groove, since the surface of the hill portion 52 is a smooth surface having a mirror surface, when the rotating member and the fixed member are relatively rotated to generate the dynamic pressure in the dynamic pressure bearing, There exists a problem that it is easy to adsorb | suck and smooth dynamic pressure generation cannot be obtained. Further, since the groove bottom surface 53 is in an uneven state, dust and the like are easily collected, and cleaning is troublesome.
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for processing a dynamic pressure generating groove of a dynamic pressure bearing that prevents adsorption to a mating member and facilitates cleaning of the groove bottom surface.
[0005]
[Means for Solving the Problems]
As a means for solving the above-mentioned problems, a dynamic pressure is formed on a plane perpendicular to the axial direction of one of the fixed member and the rotating member that rotate relative to each other and faces the plane perpendicular to the axial direction of the other member. In the processing method of the dynamic pressure generating groove of the bearing, a plurality of grooves having a smooth groove bottom surface in a plane perpendicular to the axial direction of the one member, and a plurality of dimple-shaped bottoms on the hill surface between adjacent grooves. And a first pressing step in which a recess having a shallower axial depth than the groove is simultaneously formed, and a second pressing step in which a hill surface other than the recess is formed flat. you.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Specific embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows an embodiment according to the present invention. A shaft 2 is inserted through a sleeve 1, a plurality of herringbone-shaped grooves 4 are formed on the surface of an end 2 a of the shaft 2, and the sleeve 1 and the shaft 2 are connected to each other. The relative pressure is generated by the relative rotation and functions as the dynamic pressure bearing 3. One of the sleeve 1 and the shaft 2 is a fixed member, and the other is a rotating member. Furthermore, the dynamic pressure generating groove 4 may be formed on the inner peripheral surface of the sleeve 1, and the shape of the dynamic pressure generating groove 4 is not particularly limited.
[0008]
As shown in FIGS. 2 and 3, the dynamic pressure generating groove 4 is formed as a mirror-like smooth surface with a groove bottom surface 5 of about 0.3 μm, and a large number of grooves 6 on the surface of the hill portion 6 between the grooves 4. A dimple-like concave portion 7 is formed, and the surface of the hill portion 6 other than the concave portion 7 is formed on the flat surface 8. The flat member 8 can stably receive the mating member. Moreover, the said recessed part 7 becomes a fluid pool.
[0009]
Next, a method for processing a dynamic pressure generating groove according to the present invention will be described.
In the first pressing step in FIG. 4 (A), the member 2a is pressed in the direction of arrow A by a mold S1 having a plurality of grooves 12 and a hill portion 10 between the grooves 12. The surface of the hill portion 10 of the mold S1 is a mirror-like smooth surface of about 0.3 μm, and a large number of convex portions 14 are formed on the bottom surface 13 of the groove 12. As a result, the surface of the member 2a includes a plurality of grooves 4 having a mirror-like smooth surface with a groove bottom surface 5 of about 0.3 μm and a large number of dimple-like recesses 7 on the surface of the hill portion 6 between the grooves 4 simultaneously. It is formed. Next, in the second pressing step in FIG. 4B, by pressing the surface of the hill portion 6 of the member 2a in the direction of arrow B with a mold S2 having a flat surface, the hill portions other than the dimple-like recesses 7 are obtained. 6 surfaces are formed on the flat surface 8. In this way, the dynamic pressure generating groove of the present invention is formed.
[0010]
【The invention's effect】
The dynamic pressure bearing in which the dynamic pressure generating grooves are formed by the processing method of the present invention can prevent adsorption with the mating member due to the concave portion that is a fluid pool in the hill portion between the dynamic pressure generating grooves. When the groove bottom is a smooth surface, cleaning is easy. Furthermore, since the dynamic pressure generating groove is formed by press molding with a mold, it is easy to process.
[Brief description of the drawings]
FIG. 1A is a cross-sectional view of an embodiment of the present invention, and FIG. 1B is a plan view of a shaft end surface.
FIG. 2 is a cross-sectional view of a dynamic pressure generating groove according to the XX cross section of FIG.
3 is a partial plan view of a hill portion between dynamic pressure generating grooves in FIG. 2. FIG.
4A and 4B are diagrams illustrating a method for processing a dynamic pressure generating groove according to the present invention, in which FIG. 4A is a first press process diagram, and FIG. 4B is a second press process diagram.
FIG. 5 is a cross-sectional view of a dynamic pressure generating groove of a conventional dynamic pressure bearing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sleeve 2 Shaft 3 Dynamic pressure bearing 4 Dynamic pressure generating groove 5 Groove bottom face 6 Hill part 7 Recessed part 8 Flat surface

Claims (1)

In a method for machining a dynamic pressure generating groove of a hydrodynamic bearing that is formed on a plane perpendicular to the axial direction of one of the fixed member and the rotating member that rotate relative to each other and that faces the plane perpendicular to the axial direction of the other member ,
A plurality of grooves having a smooth groove bottom surface in a plane perpendicular to the axial direction of the one member, and a plurality of dimple-shaped bottoms on the hill surface between adjacent grooves and having an axial depth greater than that of the groove A first pressing step in which a shallow concave portion is simultaneously formed,
A method for processing a dynamic pressure generating groove of a dynamic pressure bearing, comprising: a second pressing step in which a surface of a hill portion other than the concave portion is formed flat.

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