JPH0735132A - Dynamic pressure bearing unit and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a dynamic pressure bearing unit and its manufacturing method, capable of forming a symmetric groove to the central axis of a bearing even if a groove forming shaft is made eccentric to the bearing. CONSTITUTION:A groove forming shaft is slidden in the axial direction along an inner circumferential surface 1a of a bearing sleeve C, forming five dynamic pressure generating grooves 3 on this inner circumferential surface 1a and, after a shafting phase between the groove forming shaft and the bearing sleeve 1 is changed as far as almost 180 deg., this groove forming shaft is slidden in the axial direction along the inner circumferential surface 1a of the bearing sleeve 1, and five grooves 5 different as far as almost 180 deg. in phase to the five dynamic pressure generating shafts 3 is formed on the inner circumferential surface 1a. With this constitution, both these dynamic pressure generating grooves 3 and 5 are made up into a symmetrical form to a center shaft A as a whole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure bearing device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a groove machining jig 32 shown in FIG. 3 is used to form a groove for generating a dynamic pressure of a dynamic pressure bearing device. As shown in FIGS. 3 and 4 which is a sectional view taken along the line KK of FIG. 3, the groove processing jig 32 includes a shaft 33 and a pin 35 fixed to a hole 33 a provided at the tip of the shaft 33. , Axis 3
3 is composed of a plurality of balls 36 inserted and fixed in a plurality of holes 33b radially provided at equal intervals.

Conventionally, as a method of manufacturing a dynamic pressure bearing device,
As shown in FIG. 3, the groove-machining jig 32 is inserted into the bearing sleeve 31, and the groove-machining jig 32 is slid in the axial direction while rotating, so that a plurality of balls 36 arranged on the shaft 33 are inserted. Is made to run while being pressed against the inner peripheral surface of the bearing sleeve 31 to form a herringbone-shaped groove for generating dynamic pressure on the inner peripheral surface of the bearing sleeve 31.

[0004]

However, in the above-described conventional method for manufacturing a dynamic pressure bearing device, when the groove machining is performed with the central axis of the groove machining jig 32 and the central axis of the bearing sleeve 31 deviated from each other, As shown in FIG. 2, the grooves 37, 37, ... Formed on the inner peripheral surface 31a of the bearing sleeve 31 are eccentric.
That is, the groove depth of the grooves 37, 37 ...
Is not symmetrical with respect to the central axis B, and the groove depth of the grooves 37, 37 ...

Therefore, an object of the present invention is to provide a hydrodynamic bearing device and a method of manufacturing the same which can form a groove symmetrical with respect to the center axis of the bearing even if the groove forming shaft is eccentric with respect to the bearing. To provide.

[0006]

To achieve the above object, the dynamic pressure bearing device of the present invention is a dynamic pressure bearing device in which a plurality of grooves for generating dynamic pressure are formed on the inner peripheral surface of the bearing. A groove having the same size as the groove is formed on a line segment obtained by rotating a line segment connecting the groove and the central axis of the bearing by about 180 ° about the central axis. .

Further, according to the method of manufacturing a dynamic pressure bearing device of the present invention, a shaft having a natural number n of convex portions for groove formation on the outer peripheral surface is inserted into the inner peripheral surface of the bearing sleeve, and the convex portion is used to In a method of manufacturing a dynamic pressure bearing device, wherein a groove for dynamic pressure generation is formed in the bearing sleeve by relatively sliding in the axial direction along the inner peripheral surface while pressing the inner peripheral surface of the bearing sleeve, The shaft is slid in the axial direction along the inner peripheral surface of the bearing sleeve to form n grooves in the inner peripheral surface, and then the phase of the bearing sleeve with respect to the shaft is changed by about 180 °. Then, the shaft is slid in the axial direction along the inner peripheral surface of the bearing sleeve to form n grooves on the inner peripheral surface that are different in phase by about 180 ° from the n grooves. It is characterized by forming.

[0008]

In the dynamic pressure bearing device according to the present invention, the line segment connecting the groove for dynamic pressure generation and the central axis of the bearing is rotated by about 180 ° about the central axis. A groove for generating a dynamic pressure having the same size as the groove for generating a dynamic pressure is formed in the. Therefore, the groove for generating dynamic pressure has a shape symmetrical with respect to the central axis as a whole. Therefore, the dynamic pressure generated in the fluid between the bearing and the shaft by the groove has a magnitude symmetrical with respect to the central axis. Therefore, the shaft is supported in the radial direction by the dynamic pressure without being eccentric or being abutted.

According to a second aspect of the present invention, there is provided a method of manufacturing a dynamic pressure bearing device, wherein a groove forming shaft is slid in an axial direction along an inner peripheral surface of a bearing sleeve, and n grooves are formed on the inner peripheral surface. A groove is formed, and then the phase of the shaft around the shaft with respect to the bearing sleeve is changed by about 180 °, and then the shaft is slid in the axial direction along the inner peripheral surface of the bearing sleeve. On the inner peripheral surface, the phase is approximately 18 with respect to the above n grooves.
Form n grooves that differ by 0 °. Therefore, even if the central axis of the groove forming shaft is deviated from the central axis of the bearing sleeve, the formed (n + n) grooves have a symmetrical shape with respect to the central axis of the bearing sleeve.

[0010]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

An embodiment of a method of manufacturing a dynamic pressure bearing device according to the present invention will be described with reference to FIG. As shown in FIG. 1 (A), a groove machining jig similar to that shown in FIG. 3 is inserted into the inner peripheral surface 1a of the cylindrical bearing sleeve 1 and is rotated in the axial direction while rotating about the axis. Sliding to form grooves 3, 3 ... For generating dynamic pressure, having the same pitch between grooves. As shown in FIG. 1 (A), five grooves 3 are formed by sliding the groove processing jig once in the axial direction. When the groove 3 is formed, the shaft center of the groove processing jig is displaced upward in FIG. 1 (A) with respect to the shaft center of the bearing 1. The groove 3 has a larger groove depth.

Next, with the groove processing jig removed from the bearing sleeve 1, the groove processing jig or the bearing sleeve 1 is rotated by 180 ° around the axis. Then, a groove-machining jig is inserted into the bearing sleeve 1 and is slid in the axial direction while rotating around the axis in the same manner as the previous time, to form grooves 5, 5 ... For generating dynamic pressure at equal pitches. This groove 5, 5
Is 180 ° around the axis of the grooves 3, 3 shown in FIG.
It is a rotated shape. As a result, the bearing sleeve 1 has ten grooves 3, 3 as shown in FIG. 1 (C).
, 5, 5 ... are formed, and the groove 3 and the groove 5 facing each other with the central axis A of the bearing sleeve 1 in between have the same shape.

That is, the dynamic pressure generating groove 3 or 5
And a center line of the bearing sleeve 1 with a line segment that is rotated by 180 ° about the center axis A on the line segment having the same size as the groove 3 or 5 for generating dynamic pressure. A groove 5 or 3 for pressure generation is formed.

Therefore, the ten grooves including the five grooves 3 and the five grooves 5 have no eccentricity as a whole. Therefore, according to this embodiment, even if the central axis of the groove machining jig is deviated from the central axis of the bearing sleeve 1, the inner peripheral surface 1a of the bearing sleeve 1 as a whole is free from eccentricity and dynamic pressure is generated. It is possible to form the grooves 3 and 5 for use.

Therefore, the grooves 3 and 5 of the bearing sleeve 1 manufactured according to this embodiment eccentric the rotary shaft 6 by the dynamic pressure generated by the relative rotation with the rotary shaft 6 inserted in the bearing sleeve 1. It can be supported in the radial direction without causing it.

The hydrodynamic bearing device manufactured according to this embodiment is an embodiment of the hydrodynamic bearing device according to the invention of claim 1.

Also, in this embodiment, the groove machining jig is
Since the odd-numbered grooves (5 grooves) of equal pitch were formed by sliding the groove 32 times, the groove-machining jig 32 was rotated by exactly 180 ° before the second sliding operation. When forming an even number of grooves by sliding, use a groove processing jig 1 so that the grooves to be formed will have an equal pitch as a whole before the second sliding.
It may be rotated at an angle close to 80 °.

[0018]

As is apparent from the above, in the hydrodynamic bearing device according to the first aspect of the present invention, the line segment connecting the groove for generating hydrodynamic pressure and the central axis of the bearing is centered on the central axis. About 180
A groove for generating dynamic pressure having the same size as the groove for generating dynamic pressure is formed on the line segment rotated by °. Therefore,
The groove for generating dynamic pressure can be formed in a shape that is substantially symmetrical with respect to the central axis. Therefore, the groove generates a dynamic pressure generated in the fluid between the bearing and the rotating shaft inserted in the bearing,
The size can be symmetrical with respect to the central axis. Therefore, the rotary shaft is supported in the radial direction without being eccentric or being unevenly contacted.

According to a second aspect of the present invention, there is provided a method of manufacturing a dynamic pressure bearing device, wherein a groove forming shaft is slid in an axial direction along an inner peripheral surface of a bearing sleeve, and n grooves are formed on the inner peripheral surface. After forming a groove and then changing the phase around the axis of the groove forming shaft and the bearing sleeve by about 180 °, the shaft is axially moved along the inner peripheral surface of the bearing sleeve. By sliding, the phase on the inner peripheral surface is approximately 1 with respect to the n grooves.
Form n grooves that differ by 80 °. Therefore, the formed (n + n) grooves can be formed in a shape that is substantially symmetrical with respect to the central axis of the bearing sleeve.

Therefore, according to the second aspect of the present invention, it is possible to form the groove for generating the dynamic pressure having the strength symmetrical with respect to the central axis so that the axis does not become eccentric or one-sided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating an embodiment of a dynamic pressure bearing device and a manufacturing method thereof according to the present invention.

FIG. 2 is a cross-sectional view of a conventional dynamic pressure bearing.

FIG. 3 is a view showing a state in which a groove for generating dynamic pressure is formed by a groove processing jig.

FIG. 4 is a sectional view of the groove processing jig.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bearing sleeve, 1a ... Inner peripheral surface, 3, 5 ... Grooves for generating dynamic pressure, 6 ... Rotating shaft, 32 ... Jigs for groove machining.

Claims (2)

[Claims] 1. A dynamic pressure bearing device in which a plurality of grooves for generating dynamic pressure are formed on the inner peripheral surface of a bearing, wherein a line segment connecting the groove and the central axis of the bearing is centered on the central axis. And a groove having the same size as the groove is formed on a line segment rotated by approximately 180 °. 2. A shaft having a natural number n convex portion for groove formation on the outer peripheral surface is inserted into the inner peripheral surface of the bearing sleeve, and the convex portion presses the inner peripheral surface of the bearing sleeve, A method of manufacturing a dynamic pressure bearing device, wherein a groove for dynamic pressure generation is formed in the bearing sleeve by sliding the shaft relative to the inner peripheral surface of the bearing sleeve. And slide it in the axial direction to form n grooves on the inner peripheral surface. Then, the phase of the bearing sleeve with respect to the shaft is approximately 18
After changing only 0 °, slide the shaft in the axial direction along the inner peripheral surface of the bearing sleeve, and
A method for manufacturing a dynamic pressure bearing device, comprising forming n grooves having a phase difference of approximately 180 ° with respect to the n grooves.