JPH0970154A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to fix a male screw directly to a female screw at a fixing shaft body by using only one male screw when fixing an upper plate of a hard disk drive unit to a motor by providing a through-hole at the center of a thrust fixing member for fixing a thrust member contacting to a shaft end surface of the fixing shaft body. SOLUTION: A thrust member 103 is contacted to a shaft end surface 301b of a fixed shaft body 301 having a female screw and a constant outer diameter of shaft; it is fixed by a thrust fixing member 316 from above thereby forming a part of thrust dynamic fluid bearing, and a through-hole 316a is provided at the center of the thrust fixing member 316. By doing this, the through-hole 316a at the center of the thrust fixing member 316 can be fixed directly to a female screw 102 of the fixed shaft body 30 by using a male screw 113, and the fixing by one male screw 113 can be made easier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a motor having a hydrodynamic bearing for a hard disk drive.

[0002]

2. Description of the Related Art In recent years, motors are required to be small and thin, and to be required to have high-speed rotation, rotational runout accuracy, and low noise. Accordingly, a dynamic pressure fluid bearing having superior performance to a ball bearing has been developed. The used motor is being used. In addition, in recent hard disk drive devices, along with the increase in storage capacity, it is required to increase the number of disks themselves, which are media, and to improve the recording density. Support structures have been used.

[0003] A conventional motor will be described below. FIG. 2 shows a motor using a conventional hydrodynamic bearing. In FIG. 2, 101 is a fixed shaft body. A herringbone-shaped shallow groove 101a is formed on the outer peripheral surface of the fixed shaft body 101, and a female screw 102 is provided on the shaft end surface 101b.
A step 101c is formed on one side in the longitudinal direction, and a flange portion 101d is formed on the other side. Step 101
A thrust member 103 is fixed above c, and a bush member 107 for fixing and supporting the stator core 108 is attached to the flange portion 101d. A herringbone-shaped shallow groove 103 is formed on the upper and lower surfaces of the thrust member 103.
a is engraved. The winding 10 is provided on the stator core 108.
9 are wound.

Reference numeral 104 is a sleeve member. The sleeve member 104 is fitted onto the fixed shaft body 101. Lubricating oil 105 is filled in the gap between the sleeve member 104 and the fixed shaft body 101 to form a radial dynamic pressure fluid bearing capable of rotating relative to each other. Further, the sleeve member 104 fixes the thrust receiving member 106 on one side in the longitudinal direction, and faces the thrust member 103 described above. Lubricating oil 105 is filled in the gaps between the thrust member 103, the sleeve member 104, and the thrust receiving member 106 to form a thrust hydrodynamic bearing that can rotate relative to each other.

Reference numeral 110 is a rotor hub made of a magnetic material. A rotor magnet 111 is fixed to an inner wall portion 110 a of the rotor hub 110 at a position facing the stator core 108. The rotor hub 110 is fitted and fixed to the sleeve member 104.

In the motor constructed as described above, one end of the fixed shaft body 101 is connected to the base 11 of the hard disk drive.
The upper plate 11 fixed to 4 and the hard disk drive
2 can be fixed to the fixed shaft body 101 by the male screw 113 and incorporated in the drive device. And winding 109
When is energized, the rotor magnet 111 repels due to the magnetic field generated in the stator core 108, causing the rotor hub 110 to rotate about the fixed shaft body 101.

FIG. 3 shows another motor using a conventional hydrodynamic bearing. In addition, the same components as those in FIG. In FIG.
2 is different from the structure of the fixed shaft body 201 and the bracket 2 in FIG.
15 is the point newly established. The fixed shaft body 201 has a herringbone-shaped shallow groove 101a on the outer peripheral surface thereof.
1a is the same as having a female screw 102, but is different in that a flange portion 201b is integrally formed in a part in the longitudinal direction and is fixedly supported by a bracket 215. Herringbone-shaped shallow grooves 201c are engraved on the upper and lower surfaces of the flange portion 201b, and serve as a component for constructing a thrust hydrodynamic bearing similar to the motor of FIG.

The operation of the motor constructed as described above is the same as the example of the motor shown in FIG.

[0009]

However, in the above-mentioned conventional structure, as a means for constructing the thrust hydrodynamic bearing, there is provided a method for fixing the thrust member by providing a step on the fixed shaft body, or a flange portion on the fixed shaft body. Since the method of providing and integrating is used, there is a problem that processing of the fixed shaft is complicated and difficult, resulting in high cost. In particular, the squareness accuracy between the thrust member for forming the thrust dynamic pressure fluid bearing and the shaft center line of the fixed shaft body for forming the radial dynamic pressure fluid bearing is determined by the bearing rigidity and reliability of the motor or thrust play in units of several μm. And the larger the diameter of the thrust member, the more likely it is that effect will appear. The same applies to the integral flange portion such as the motor of FIG. 3, and in the case of this motor configuration, in addition to the above-mentioned problems, it becomes difficult to secure the accuracy of the finished surface roughness of the upper and lower surfaces of the flange.

On the other hand, however, when the motor is incorporated into the hard disk drive, the upper plate of the drive unit can be easily fixed to the fixed shaft body of the motor with one male screw, and the male screw is directly attached to the fixed shaft body. Since it is fixed to the screw part, it has the advantage of excellent mechanical rigidity.

The present invention solves the above-mentioned problems of the prior art. As means for constructing a thrust hydrodynamic bearing, steps and flanges are not set on the fixed shaft body, and the upper plate and the motor of the hard disk drive device are not set. Only one male screw is used for fixing with and the male screw can be directly fixed to the female screw of the fixed shaft body. At the same time, another object is to provide a low-cost motor having a bearing structure.

[0012]

In order to achieve this object, a motor of the present invention has a thrust fixing member contacting a thrust member to the shaft end surface of a fixed shaft body having a constant shaft outer diameter and having an internal thread from above. Is a part of the thrust dynamic pressure fluid bearing, and the through hole is provided in the center of the thrust fixing member.

[0013]

With this structure, by providing the through hole at the center of the thrust fixing member, the male screw can be directly fixed to the female screw of the fixed shaft body when fixing the upper plate of the hard disk drive and the motor. At the same time, it can be fixed with one male screw. Further, since the outer diameter of the fixed shaft is constant, the surface on which the thrust member is mounted can be machined easily and highly accurately. As a result, it is possible to configure the bearing portion at low cost and with high accuracy, and it is possible to reduce the influence on the performance and reliability of the motor.

[0014]

An embodiment of the present invention will be described below with reference to the drawings. The same components as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, what is different from the conventional examples shown in FIGS. 2 and 3 is that the outer diameter of the fixed shaft 301 is constant and a thrust fixing member 316 is newly provided.

The fixed shaft body 301 has a constant axial outer diameter with respect to the longitudinal direction, and has a recess 301a for fixing a thrust fixing member 316 described later on the shaft end surface 301b. Further, a female screw 102 is provided on the bottom surface portion 301c of the recess 301a.

The thrust member 103 is in contact with the shaft end surface 301b and maintains the squareness with respect to the axial center line of the fixed shaft body 301. The thrust fixing member 316 has a through hole 316 in the center.
a. Further, the thrust fixing member 316 is fixed to the fixed shaft body 30 via the inner peripheral portion 103 b of the thrust member 103.
The thrust member 103 can be fixed by contacting the step portion 316c of the thrust fixing member 316 and the shaft end surface 301b of the fixed shaft body 301 with the convex portion 316b for inserting and fixing it in the first concave portion 301a. .

In the motor constructed as described above, the bracket 215 is fixed to the base 114 of the hard disk drive, and the upper plate 112 of the hard disk drive is directly fixed by the male screw 113 via the thrust fixing member 316. By being fixed to the body 101, it can be incorporated in the driving device. The description of the operation of the motor is omitted because it is the same as the conventional example.

As described above, according to this embodiment, when the motor using the hydrodynamic bearing of the shaft fixed type and the both ends supported type is fixed to the upper plate of the hard disk drive, it is possible to fix with one male screw. Since this is possible and the male screw can be directly fixed to the female screw of the fixed shaft body, it is easy and there is no problem in terms of coupling rigidity such as insufficient fixing strength. For example, it is possible to provide a female screw on the thrust fixing member itself and fix it to the upper plate of the hard disk drive device with a male screw, but the screw depth in the longitudinal direction cannot be large, and there is a problem with the coupling strength with the fixed shaft Will be.

Further, since the fixed shaft body having a constant shaft outer diameter in the longitudinal direction is used, it becomes easy to finish the outer peripheral surface with high precision by machining such as centerless polishing, and the shaft end surface of the fixed shaft body is Since the squareness accuracy can also be finished with high accuracy, the squareness between the thrust member that is mounted in contact with the shaft end surface of the fixed shaft body and the axis stop line of the fixed shaft body can be obtained, and a highly accurate thrust dynamic pressure fluid bearing can be obtained. Can be configured. Further, by using a fixed shaft body having a constant shaft outer diameter, it is possible to realize a bearing structure at low cost.

In this embodiment, when the thrust fixing member is made of a resin material having oil repellency, it is possible to effectively prevent the oil from leaking out from the thrust hydrodynamic bearing.

[0022]

As described above, according to the present invention, a fixed shaft body having a constant shaft outer diameter and an internal thread and a relative sliding surface of a sleeve member externally fitted to the fixed shaft body are radially interposed via lubricating oil. It constitutes a hydrodynamic bearing. In addition, thrust dynamic pressure is applied to the relative sliding surfaces of the thrust member, which is in contact with the shaft end surface of the fixed shaft body and is fixed by the thrust fixing member, and the sleeve member and thrust receiving member facing the thrust member, through lubricating oil. The fluid bearing is configured and a through hole is provided in the center of the thrust fixing member. The through hole at the center of the thrust fixing member allows the male screw to be directly fixed to the female screw of the fixed shaft body when fixing the upper plate of the hard disk drive and the motor, and can be easily fixed with one male screw. It is possible and does not affect the coupling rigidity between the hard disk drive and the motor. In addition, by using a fixed shaft with a constant shaft outer diameter, it is possible to configure a highly accurate hydrodynamic bearing part for both the radial and thrust parts, which suppresses the effects on the characteristics and reliability of the motor and reduces It is possible to realize an excellent motor capable of forming a costly fluid bearing portion.

[Brief description of drawings]

FIG. 1 is a sectional view of a motor according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional motor

FIG. 3 is a sectional view of another conventional motor.

[Explanation of symbols]

101, 201, 301 Fixed shaft body 101a, 103a, 201c Herringbone-shaped shallow groove 101c Steps 101d, 201b Flange portion 102 Female screw 103 Thrust member 103b Inner peripheral portion 104 Sleeve member 105 Lubricating oil 106 Thrust receiving member 107 Bush member 108 Stator core 109 Winding 110 Rotor hub 110a Inner wall part 111 Rotor magnet 112 Upper plate 113 Male screw 114 Base 101b, 201a, 301b Shaft end surface 215 Bracket 301a Recess 301c Bottom part 316 Thrust fixing member 316a Through hole 316b Convex part 316c Step part

Claims (4)

[Claims] 1. A fixed shaft body having a constant shaft outer diameter and having an internal thread, a sleeve member externally fitted to the fixed shaft body, a thrust member in contact with a shaft end surface of the fixed shaft body, and the thrust member. And a thrust receiving member facing the thrust member, and a relative sliding surface of the fixed shaft body and the sleeve member, a thrust member, the sleeve member, and the thrust receiving member. What is claimed is: 1. A motor having a radial and thrust bearing portion with a lubricating oil interposed on a sliding surface, wherein the thrust fixing member has a through hole at the center thereof. 2. The motor according to claim 1, wherein the radial dynamic pressure bearing is formed by providing a spiral groove or a herringbone groove on at least one of the outer peripheral surface of the fixed shaft body and the inner peripheral surface of the sleeve. 3. The motor according to claim 1, wherein a spiral hydrodynamic bearing is formed by providing a spiral groove or a herringbone groove on a relative sliding surface of the thrust member and the sleeve member and the thrust receiving member. 4. The motor according to claim 1, wherein the thrust fixing member is made of a resin material having oil repellency.