JP2002139029A - Manufacturing method for dynamic pressure type bearing unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method capable of controlling a thrust bearing gap with a good accuracy and a low cost. SOLUTION: A jig 15 is disposed on one end opening side of a housing. This jig 15 has a standard surface 15a; and an abutment surface 15b projected against the standard surface 15a by an amount δcorresponding to the sum of width of thrust bearing gaps Cs1, Cs2. A shaft member 3 is inserted from the other end opening side of the housing 5 and an end surface 3b2 of a flange part 3b is abutted to the abutment surface 15b of the jig 15. In this state, a bearing member 7 is inserted to the housing 5 and the shaft part 3a of the shaft member 3. An end surface 7a thereof is abutted to the end surface 3b1 of the flange part 3b and is fixed to an inner periphery of the housing 5 at the position. The jig 15 is removed from the one end opening part of the housing 5. Thereafter, a closing member 9 is engaged with an engagement part 5a of the housing 5 and is fixed thereto by a means such as an adhesion and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic pressure type bearing unit. This bearing unit is used especially for information equipment, for example, a magnetic disk drive such as HDD, FDD, etc.
Optical disk devices such as D-ROM and DVD-ROM, M
It is suitable for supporting a spindle motor such as a magneto-optical disk device such as D or MO, or a spindle scanner motor such as a polygon scanner motor of a laser beam printer (LBP).

[0002]

2. Description of the Related Art Spindle motors for various information devices are required to have high rotational accuracy, high speed, low cost, low noise, and the like. One of the components that determine these required performances is a bearing that supports the spindle of the motor.In recent years, the use of a dynamic pressure bearing having characteristics excellent in the required performance as this type of bearing has been studied, or Used in practice.

[0003]

A dynamic pressure bearing is a type in which a fluid dynamic pressure is generated in a radial bearing gap or a thrust bearing gap during relative rotation between a shaft member and a bearing member to support the two members in a non-contact manner. In the conventional dynamic pressure bearing unit, complicated operations such as dimensional measurement are required in order to accurately manage the thrust bearing gap, and an increase in cost due to an increase in the number of assembly steps has been pointed out as a problem.

An object of the present invention is to provide a method of manufacturing a dynamic pressure type bearing unit capable of managing a thrust bearing gap accurately and at low cost.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a housing, a bearing member fixed to an inner periphery of the housing, a shaft member having a shaft portion and a flange portion, a shaft member and a bearing. Method of manufacturing a dynamic pressure bearing unit including a radial bearing portion and a thrust bearing portion for supporting a shaft member in a radial direction and a thrust direction in a non-contact manner by dynamic pressure generated in a radial bearing gap and a thrust bearing gap during relative rotation with a member The shaft member is housed in a housing having both ends opened, the shaft member is positioned and held at a predetermined position by a jig from one end opening side of the housing, and in that state, the bearing member is moved from the other end opening side of the housing to the housing and It is inserted into the shaft of the shaft member, the end surface of which is brought into contact with the end surface of the flange portion of the shaft member, and the bearing member is fixed to the housing at that position. , Remove the jig to provide a production method comprising the step of sealing the mouth of one end opening of the housing in sealing member.

In the above arrangement, the jig is provided with a reference surface to be engaged with the housing, and a contact surface protruding from the reference surface by the gap width of the thrust bearing gap, and the reference surface is engaged with the housing. In this state, it is preferable that the shaft member is positioned by bringing the end surface of the flange portion into contact with the contact surface of the jig. In this case, an accurate thrust bearing gap can be easily obtained by engaging the sealing member with the engaging portion of the housing that engages with the reference surface of the jig.

In the dynamic pressure bearing unit obtained by this method, since the thrust bearing gap is accurately controlled,
During relative rotation between the shaft member and the bearing member, there is no unstable rotation due to contact between thrust bearing surfaces or insufficient dynamic pressure in the thrust bearing gap, and high rotational accuracy is achieved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The main components of the bearing unit 1 are a shaft member 3, a housing 5, and a bearing member 7 fixed to the inner periphery of the housing 5. One end opening of the housing 5 is sealed by a sealing member 9, and the other end opening is sealed by a sealing member such as a seal washer (not shown). The shaft member 3 has a shaft portion 3a and a flange portion 3b provided at one end of the shaft portion 3a. The shaft portion 3a is provided on the inner periphery of the bearing member 7, and the flange portion 3b is provided on the bearing member 7 and the housing 5. And is housed in the unit by being arranged between the sealing member 9 and the bottom of the sealing member 9. The shaft portion 3a and the flange portion 3b of the shaft member 3 may be formed as an integrated structure or may be formed as separate structures.

The bearing member 7 is made of a soft metal or a sintered metal impregnated with oil. A radial bearing surface 11a having a plurality of dynamic pressure grooves is formed on the inner peripheral surface of the bearing member 7 by transfer, rolling, or the like by press working, whereby the shaft member 3 and the bearing member 7 are rotated relative to each other. At the time of rotation of the shaft member 3 in the embodiment), a dynamic pressure of a fluid (for example, lubricating oil) filled in the radial bearing gap Cr between the radial bearing surface 11a and the outer peripheral surface of the shaft portion 3a is generated. A radial bearing portion 11 that supports the shaft portion 3a in a non-contact manner in the radial direction by the action is configured.

Thrust bearing gaps Cs1 and Cs2, which are gaps in the axial direction, are provided on both axial sides of the flange portion 2b. The thrust bearing gap Cs1 is formed between one end face 3b1 of the flange 3b and the end face 7a of the bearing member 7 opposed thereto, and the other thrust bearing gap Cs2 is formed between the other end face 3b2 of the flange 3b, It is formed between the end surface 3b2 and the inner surface of the sealing member 9 facing the end surface 3b2. End faces facing the thrust bearing gaps Cs1, Cs2, for example, both end faces 3 of the flange portion
Thrust bearing surfaces 13a and 13b each having a dynamic pressure groove for generating a dynamic pressure are formed on b1 and 3b2 by press working or the like.
The thrust bearing portion 13 for non-contact support of the flange portion 3b from both sides in the thrust direction due to the generation of the fluid dynamic pressure in Cs2.
Is configured.

The shape of the dynamic pressure grooves of the radial bearing surface 11a and the thrust bearing surfaces 13a, 13b can be arbitrarily selected, and may be any of well-known herringbone type, spiral type, step type, multi-arc type and the like. They can be selected or used in appropriate combination.

The dynamic pressure type bearing unit 1 is assembled according to the procedure shown in FIG. During this assembly, the radial bearing surface 11a having the dynamic pressure grooves and the thrust bearing surface 13
The processing of a and 13b has already been completed.

First, a jig 15 is placed at one end opening side of the housing.
Place. The jig 15 has a reference surface 15a and a contact surface 15b protruding from the reference surface 15a by δ corresponding to the sum of the widths of the thrust bearing gaps Cs1 and Cs2. Set to about. The jig 15
The reference surface 15a is inserted into the one end opening of the housing 5 in a state where the reference surface 15a is engaged with the engaging portion 5a provided in the one end opening of the housing 5 and the contact surface 15b is arranged on the inner periphery of the housing 5. . Therefore, the contact surface 15b of the jig 15
It is located at a position protruding from the engaging portion 5 a of the housing 5 by the dimension δ inside the housing 5.

Next, in this state, the shaft member 3 is inserted from the other end opening side of the housing 5, and the end face 3b2 of the flange portion 3b is brought into contact with the contact face 15b of the jig 15. Thus, the end surface 3b2 of the flange portion 3b of the shaft member 3 is positioned and held at a position of the dimension δ from the engaging portion 5a of the housing 5. In this state, the bearing member 7 is inserted into the housing 5 and the shaft portion 3a of the shaft member 3 (the outer periphery of the bearing member 7 is inserted into the inner periphery of the housing 5 and the inner periphery of the bearing member 7 is The end face 7a is brought into contact with the end face 3b1 of the flange 3b, and the bearing member 7 is fixed to the inner periphery of the housing 5 at that position. Thereby, the position of the bearing member 7 with respect to the housing 5 is accurately determined. That is, the end face 7 a of the bearing member 7 has the engagement portion 5 a of the housing 5.
(The dimension δ + the width of the flange portion 3b). Pressing or bonding can be considered as a fixing method in this case.

Next, the jig 15 is removed from one end opening of the housing 5, and then the sealing member 9 is fitted to the engaging portion 5a of the housing 5 and fixed by means such as bonding. Thereby, the bearing unit 1 of the form shown in FIG. 1 is obtained.

According to the above manufacturing method, the sum of the widths of the two thrust bearing gaps Cs1 and Cs2 is equal to the height δ of the contact surface 15b of the jig 15. Therefore, the contact surface 15b of the jig 15
By controlling the height δ, the thrust bearing clearance C
The sizes of s1 and Cs2 can be managed accurately and easily.

[0018]

According to the present invention, the thrust bearing gap of the dynamic pressure type bearing unit can be accurately formed by a simple process, so that the stability and reliability of the bearing performance can be improved while reducing the cost. Can be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a hydrodynamic bearing unit manufactured by the method of the present invention.

FIG. 2 is a cross-sectional view illustrating a method of manufacturing the dynamic pressure bearing unit according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 dynamic pressure bearing unit 3 shaft member 3a shaft portion 3b flange portion 5 housing 5a engaging portion 7 bearing member 7a end face 9 sealing member 11 radial bearing portion 11a radial bearing surface 13 thrust bearing portion 13a thrust bearing surface 13b thrust bearing surface 15 Tool 15a Reference surface 15b Contact surface Cr Radial bearing clearance Cs1 Thrust bearing clearance Cs2 Thrust bearing clearance

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mori Natsuhiki 3066 Oyumida, O-Ju, Kuwana-shi, Mie F-term in NTN Co., Ltd. (reference) HA01

Claims (3)

[Claims] 1. A housing, a bearing member fixed to an inner periphery of the housing, a shaft member having a shaft portion and a flange portion, and a radial bearing gap and a thrust bearing gap formed when the shaft member and the bearing member rotate relative to each other. A method for manufacturing a dynamic pressure bearing unit including a radial bearing portion and a thrust bearing portion for non-contactly supporting a shaft member in a radial direction and a thrust direction by a generated dynamic pressure, wherein the shaft member is housed in a housing having both ends opened. The shaft member is positioned and held at a predetermined position by a jig from one end opening side of the housing, and in this state, the bearing member is inserted into the housing and the shaft portion of the shaft member from the other end opening side of the housing, and the end face is inserted into the shaft member. Abutting against the end surface of the flange portion of the housing, and fixing the bearing member to the housing at that position.Then, remove the jig and seal the opening at one end of the housing. Method of manufacturing a hydrodynamic type bearing unit comprising a step of sealing mouth member. 2. A jig is provided with a reference surface to be engaged with the housing and a contact surface protruding from the reference surface by an amount corresponding to a gap width of a thrust bearing gap, and the reference surface is engaged with the housing. 2. The method for manufacturing a dynamic pressure bearing unit according to claim 1, wherein the shaft member is positioned by contacting an end surface of the flange portion with a contact surface of the jig. 3. The method of manufacturing a dynamic pressure bearing unit according to claim 2, wherein the sealing member is engaged with an engaging portion of the housing which engages with the reference surface of the jig.