JPH05146128A - Spindle motor - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to easily seal a through hole of a hub member and to apply a reliable preload to a bearing member without using an adhesive or the like. A hub member for mounting a recording disk, a bearing member, and a stationary member for holding the bearing member are provided, and the hub member is driven to rotate relative to the stationary member via the bearing member. It The hub member is provided with a through hole coaxially with the rotation axis. The recording disk mounting side, which is one end of the through hole, was used as a mounting hole for the clamp member. A screw member is screwed onto the other end of the through hole to substantially seal the through hole. The screw member exerted a preload on the bearing member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor mounted on an optical / magnetic disk drive, for example, for rotating a recording disk.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a left half of a spindle motor for rotationally driving a magnetic disk, which is a recording disk, for example. In FIG.
A magnetic disk a is mounted on a bowl-shaped hub member b, a substantially disk-shaped clamp member c is attached to the hub member b from above, and then a mounting screw d is tightened in the hole j. As a result, the state in which the magnetic disk a is pressed and fixed to the hub member b is shown in FIG.
Is shown in.

A shaft portion i for rotatably supporting the hub member b is formed integrally with the hub member b, and a hole portion j into which a mounting screw d is screwed is provided coaxially with the shaft portion i. ing. That is, the clamp member c is mounted and fixed by the so-called center clamp system, which is fixed at the rotation axis of the hub member b.

On the other hand, the bracket e, which is a stationary member, includes
A cylindrical portion h is provided, and a pair of ball bearings f, f is interposed between the cylindrical portion h and the shaft portion i. Then, a fixed position preload is applied to these ball bearings f, f according to the preload action line of m, m, and in this state, the hub member b is rotatable with respect to the bracket e. The state of being supported is shown.

[0005]

By the way, the hub member b
It is desirable that the hole j of the above is penetrated in the axial direction with respect to the shaft i. By forming the through holes, the surface treatment liquid and the like can be evenly distributed and rust and the like can be reliably prevented. However, through such through holes,
If lubricant fine particles, dust or the like of the ball bearing f inside the hub member b leaks to the outside (that is, the magnetic disk a side), the inside of the disk chamber is contaminated, which is inconvenient. Therefore, it is necessary to seal this through hole by some method,
For example, there is a method of filling the adhesive, but there are problems such as management of the filling amount of the adhesive, injection means, and leakage of the adhesive, and problems to be solved in terms of manufacturing the spindle motor and quality. It was complicated.

On the other hand, the required fixed position preload is applied to the ball bearings f, so that the following operation is performed. That is, the side surface of the inner ring portion k of the ball bearing f positioned on the lower side in the figure is pressed inward in the axial direction (upward in the figure) so that the preload acting lines m, m can be generated. In this state, the inner and outer races of the ball bearings f are bonded and fixed to the inner peripheral surface of the cylindrical portion h and the outer peripheral surface of the shaft portion i corresponding to the respective portions.

However, according to this conventional method,
Not only the step of applying the adhesive is required, but also the time required for preload fixing of the adhesive is added, and in addition, it is necessary to control the application amount and the application state of the adhesive. Further, due to uncured adhesive or the like, there is a risk of contact failure of the ball bearing due to preload loss, bleeding of adhesive or the like, or adhesive gas leaking into the disk chamber and contaminating it. As described above, there are various problems in manufacturing and quality of the spindle motor.

The present invention has been made in view of the above problems existing in the prior art. The problem is that the clamp member mounting hole provided in the rotation axis portion of the hub member is provided. Even if it is a through hole, it can be easily sealed without using a filler or the like, and a reliable preload can be applied to the bearing member without using an adhesive or the like. It is to provide a high spindle motor.

[0009]

In order to achieve the above object, the spindle motor of the present invention comprises a hub member for mounting a recording disk, a bearing member, and a stationary member for holding and fixing the bearing member. In the spindle motor in which the hub member is driven to rotate relative to the stationary member via the bearing member, the hub member is provided with a through hole coaxially with the rotation axis. The recording disk mounting side which is one end of the through hole is used as a mounting hole of a clamp member for holding and fixing the recording disk, and a screw member is screwed into the other end portion of the through hole, and the through hole is formed. At the same time as substantially sealing, the screw member is in contact with the bearing member and substantially presses it in the direction of the rotation axis to apply a preload to the bearing member.

Further, the stationary member is a base member which defines a disc chamber for accommodating the recording disc.

[0011]

[Operation] A screw member is screwed to the other end of the through hole,
At this screwing point, the inside and outside of the communicating through hole are substantially closed. Therefore, unclean air, gas, etc. inside the spindle motor do not leak to the recording disk side. Further, the screw member pushes the side surface of the bearing member substantially in the rotation axis direction by being screwed into the through hole. In this case, the screw member restricts the bearing member to a fixed position. Then, this pressing force becomes a required preload of the bearing member and continuously acts. Therefore, the bearing member does not need to be fixed by adhesion.

Next, since the stationary member is a base member which defines a disk chamber for accommodating a recording disk, the number of parts, the number of assembling steps, etc. are reduced, and the productivity is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing a left half of a spindle motor for driving a recording disk (for example, a magnetic disk) as one embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a bowl-shaped hub member, and a flange portion 9 and an outer peripheral portion 2 of the hub member 1 are provided.
A recording disk 18 having a donut shape is mounted on the disk. Three recording disks 18 are sequentially stacked via a spacer 19, and are held by a clamp member 20 provided on the uppermost part thereof.

The clamp member 20 has a substantially disc shape,
It has a mounting hole 51 provided coaxially with the rotation axis 40 that is the center thereof. For fixing to the hub member 1, the mounting screw 21 is inserted into the mounting hole 51 and screwed to the screw portion 22 provided on the shaft portion 3 of the hub member 1. This makes 3
The recording disk 18 is integrally held and fixed to the hub member 1, and is rotationally driven together with the hub member 1.

A shaft portion 3 for rotatably supporting the hub member 1 is erected at the center of the hub member 1, and a rotation axis 4 is provided.
It is formed coaxially and integrally with 0. A through hole 4 is provided inside the shaft portion 3. Similarly, the through hole 4 also extends coaxially with the rotation axis 40, and the clamp member 20 is screwed by a mounting screw 21 on the mounting side of the recording disk 18, which is one end thereof, that is, on the upper side of the drawing. It has a threaded portion 22 for attachment.

A screw portion 26 is provided at the other end of the through hole 4. The screw member 5 is attached to the screw portion 26 from the lower side to the upper side of the drawing, that is, the rotation axis 40.
It is screwed in the upward direction. The screw member 5 substantially seals the through hole 4. Therefore, it is possible to effectively prevent the dust existing inside the spindle motor, the lubricant fine particles scattered from the ball bearings 23 and 24, from passing through the through hole 4 to the disk indoor space 25 communicating with the through hole 4. be able to.

Reference numeral 6 is a fixed base of the spindle motor and a bracket which is a stationary member. The bracket 6 has a substantially shallow dish shape, and the rotation axis 40 is provided at the center thereof.
On the other hand, a cylindrical portion 10 that is erected coaxially is integrally formed. Further, the outer peripheral end portion 52 of the bracket 6 is fixed to the base member 7. The base member 7 defines a disc chamber in which the recording disc is housed.

Inside the cylindrical portion 10, that is, the rotation axis 40
On the side, a pair of ball bearings 23, 24, which are bearing members, are mounted and held at predetermined intervals.
The shaft portion 3 of the hub member 1 is rotatably supported via 24. On the other hand, a stator (armature) 15 is fitted and fixed to the outer peripheral surface 38 of the cylindrical portion 10, and a rotor magnet (field magnet) is provided on the inner peripheral surface 39 of the hub member 1 so as to face the stator 15. 17 are arranged in an annular shape. Then, the stator 15 and the rotor magnet 17 drive relative rotation. 16 is a rotor magnet 17
It is a yoke member.

Since the flange portion 9 of the hub member 1 and the bottom surface portion 11 and the inner peripheral side surface portion 8 of the bracket 6 are brought close to each other to form a labyrinth seal structure, dust and the like inside the spindle motor is kept inside the disk chamber. It is prevented from flowing out into the space 25. A seal member 13 is attached to the bracket 6 so that the airtightness inside the spindle motor can be improved.

In the ball bearing 23, the outer ring portion 32 is
The bracket 6 is positioned and fitted to the inner peripheral surface 34 and the stepped portion 28 provided on the cylindrical portion 10 of the bracket 6, and the inner ring portion 30 includes the outer peripheral surface 33 and the bottom portion 3 of the shaft portion 3 of the hub member 1.
1 is positioned and fitted. Both are fitted with a loose fit. Further, in the ball bearing 24, the outer ring portion 29 is positioned and fitted into the inner peripheral surface 35 and the step portion 27 of the cylindrical portion 10, and is likewise mounted by loose fitting.

Therefore, in this case, the above-mentioned screw member 5 is
When the screw member 5 of the through hole 4 is screwed and advanced, the side end portion 14 of the screw member 5 causes the inner ring portion 12 of the ball bearing 24 (specifically, the lower side surface in the drawing). Part). The screw member 5 is screwed in the upward direction on the rotation axis 40 in the drawing, so that the side end portion 14 is moved to the inner ring portion 1.
2 is pressed substantially upward in the figure on the axis of rotation 40.
This pressing force generates preload acting lines 36 and 37 shown in the drawings for the ball bearings 24 and 23, respectively. As a result, the ball bearings 23, 24 are preloaded in a fixed position with respect to the cylindrical portion 10 and the shaft portion 3.

The position in the direction of the rotation axis 40 is sequentially changed depending on the degree of screwing of the screw member 5, so that the preload can be controlled freely by this screwing adjustment. And
The preload continues to work. In this way, since preload can be applied at the same time when assembling the spindle motor, there is no need for time to apply the adhesive and cure it while applying the preload, as compared with the case of using the conventional adhesive. Further, various inconveniences caused by the uncured adhesive are not generated. Further, the pressing force corresponding to the required preload is set for each type of spindle motor, but in the spindle motor of this configuration, it can be performed only by adjusting the screw advance of the screw member, which is extremely easy.

Next, one example of the assembling order of the embodiment of the spindle motor shown in FIG. 1 will be described with reference to FIGS. The same members used in FIG. 1 are given the same numbers. Further, the right half of the drawing showing the cross section is omitted. In FIG. 2, first, the rotor magnet 17 and the yoke member 16 are fixed to the inner peripheral surface 39 of the hub member 1 with an adhesive or the like. Next, the ball bearing 23 is fitted into the shaft portion 3 as shown by the arrow in the figure. In this case, the side surface of the inner ring portion 30 on the upper side in the drawing is brought into contact with the bottom portion 31 of the hub member 1. Since the fitting is preset to be loose, the ball bearing 23 is easily fitted. On the other hand, on the bracket 6 side, the stator 15 is attached to the cylindrical portion 10 in advance.

In FIG. 3, the ball bearing 24 is fitted into the cylindrical portion 10 from the bottom to the top of the drawing. The ball bearing 24 has an inner peripheral surface 3
5 and the step portion 29 are positioned and mounted. Next, the hub member 1 is inserted toward the cylindrical portion 10 in the direction of the arrow in the figure. In this case, the lower side surface of the outer ring portion 32 of the ball bearing 23 in the figure is brought into contact with the step portion 28 of the cylindrical portion 10. In this way, the hub member 1 and the bracket 6 are assembled via the ball bearings 23 and 24.

FIG. 4A shows this assembled state. Then, the screw member 5 is attached to the screw portion 26 and screwed as shown by the arrow. As shown in (b) of FIG. 4, after the side end portion 14 of the screw member 5 comes into contact with the (lower side in the drawing) side surface of the inner ring portion 12, the screw member 5 is screwed by a predetermined amount, Apply the required preload. Ball bearing 2
Preload action lines 37 and 36 are generated at 3 and 24. Finally, the seal member 13 is attached to the bracket 6.

FIG. 5 is a sectional view showing another embodiment of the spindle motor according to the present invention. The same members as those of the spindle motor described in FIG. 1 are designated by the same reference numerals. Since the description is duplicated, only the points different from the spindle motor shown in FIG. 1 will be described. First, the stationary member is replaced with the bracket 6 shown in FIG.
In this embodiment, the base member 5 that defines the disk chamber 25
That is 0. The base member 50 and the upper lid 55 define a closed space for accommodating the recording disc 18, that is, the disc chamber 25. A seal member made of an elastic material is interposed at the joint between the base member 50 and the lid 55. Therefore, according to this embodiment, the number of parts is reduced, and the assembling becomes easier.

Further, the through hole 4 of the shaft portion 3 is not provided with a screw portion, but instead, a tube member 52 made of a plastic material is inserted. Clamp member 20
The mounting screw 21 and the screw member 5 of the tube member 5 are
2 is screwed while being threaded. For this reason, the inner peripheral surface 51 of the through hole 4 does not require a screw portion, so that the surface treatment liquid can more easily permeate. In addition, the sealing effect of the screw member 5 with respect to the through hole 4 is further improved, and the loosening prevention effect of the screw member 5 is also increased, so that the reliability can be improved.

Although the embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to this embodiment, and various modifications and corrections can be made without departing from the scope of the present invention. .. For example, although the clamp member 20 is fixed to the hub member 1 by screwing the clamp member 20 into the through hole 4 in the present embodiment, a method of inserting a pin-shaped attachment may be used. As the screw member 5, screws having various shapes can be used, and the portion of the screw member that contacts the ball bearing can be freely set. As for the part of the ball bearing with which the screw member abuts, the inner ring part has been described in the present embodiment, but of course, it may be abutted on the outer ring part due to the holding structure of the ball bearing. Besides, the base member 50 is shown as being assembled with the lid 55, but the base member 50 may also serve as the lid 55.

[0029]

According to the spindle motor of the present invention, the screw member screwed to one end of the shaft portion of the hub member on which the recording disk is mounted is used as the sealing means for closing the through hole, and the bearing member is preloaded. The preload adding means is added. For this reason, since no fillers or adhesives are used, not only the step of injecting or applying them, but also the associated quantity and quality control becomes unnecessary. The inconvenience caused by the uncured adhesive is also eliminated.

Further, since the base member is integrated with the accommodating portion for accommodating the recording disk, the space saving and the size reduction can be achieved, and the spindle motor having high productivity and reliability can be obtained.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view for explaining an assembling order of the spindle motor shown in FIG.

FIG. 3 is a sectional view for explaining an assembling order of the spindle motor shown in FIG.

FIG. 4 is a cross-sectional view for explaining an assembling order of the spindle motor shown in FIG.

FIG. 5 is a sectional view showing another embodiment of the spindle motor according to the present invention.

FIG. 6 is a sectional view showing a conventional spindle motor.

[Explanation of Codes] 1 hub member 4 through hole 5 screw member 18 recording disk 20 clamp member 21 mounting screw 23 ball bearing 24 ball bearing 40 rotation axis 50 base member

Claims (2)

[Claims] 1. A hub member for mounting a recording disk, a bearing member, and a stationary member for holding the bearing member,
In a spindle motor in which the hub member is driven to rotate relative to the stationary member via the bearing member, a through hole is provided in the hub member coaxially with a rotation axis, and one end of the through hole is provided. The recording disk mounting side, which is a portion, is used as a mounting hole for a clamp member for holding and fixing the recording disk, and a screw member is screwed to the other end of the through hole to substantially define the through hole. The spindle motor according to claim 1, wherein the screw member abuts on the bearing member and presses the bearing member substantially in the rotational axis direction while applying a preload to the bearing member. 2. The spindle motor according to claim 1, wherein the stationary member is a base member that defines a disk chamber in which the recording disk is accommodated.