JP3253658B2 - Spindle motor - Google Patents

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, for example, an optical / magnetic disk drive 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 rotating a magnetic disk, for example, a recording disk. 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 into the hole j. FIG. 6 shows a state in which the magnetic disk a is pressed and fixed to the hub member b.
Is shown in

[0003] A shaft portion i for rotatably supporting the hub member b is formed integrally with the hub member b, and a hole 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 attached and fixed by a so-called center clamp method fixed at the rotation axis of the hub member b.

On the other hand, a bracket e as a stationary member includes:
A cylindrical portion h is provided, and a pair of ball bearings f, f are interposed between the cylindrical portion h and the shaft portion i. A fixed position preload is applied to these ball bearings f, f according to the preload action line of m, m. FIG. 6 shows that the hub member b is rotatable with respect to the bracket e in this state. This shows a supported state.

[0005]

The hub member b
The hole j is desirably made to penetrate the shaft i in the axial direction. By forming the through holes, the surface treatment liquid and the like can be evenly distributed, and the generation of rust and the like can be reliably prevented. However, through such through holes,
If lubricant particles, dust, etc. of the ball bearing f inside the hub member b leak to the outside (that is, the magnetic disk a side), the disk chamber is contaminated, which is inconvenient. Therefore, it is necessary to seal this through-hole by some method,
For example, there are methods such as filling with an adhesive, but there are problems such as management of the filling amount of the adhesive and injection means, or bleeding of the adhesive, and problems to be solved in manufacturing, quality, and the like of the spindle motor. And it was complicated.

On the other hand, since a required fixed-position preload is applied to the ball bearings f, f, the following operation is performed. That is, the side surface of the inner ring portion k is pressed inward in the axial direction (upward in the figure) against the ball bearing f located on the lower side in the figure so as to generate the preload action lines m, m. In this state, the inner and outer rings of the ball bearings f, f are bonded and fixed to the inner peripheral surface of the cylindrical portion h corresponding to each part and the outer peripheral surface of the shaft portion i.

However, according to this conventional method,
Not only does a step of applying the adhesive be required, but also the time required for pre-pressure fixing of the adhesive is added, and it is necessary to control the amount and state of application of the adhesive. In addition, due to the uncured adhesive or the like, there is a risk of contact with the ball bearing due to a loss of preload or leakage of the adhesive, or a possibility that the gas of the adhesive leaks into the disk chamber and is contaminated. As described above, there are various problems in manufacturing and quality of the spindle motor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and an object thereof is to provide a mounting hole for a clamp member provided in a rotation axis portion of a hub member. 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]

To achieve the above object, a spindle motor according to the present invention comprises a hub member on which a recording disk is mounted, 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, the hub member is provided with a through-hole coaxially with respect to a rotation axis. The recording disk mounting side, which is one end, is used as a mounting hole for a clamp member for holding and fixing the recording disk, and a screw member is screwed into the other end of the through hole. At the same time, the screw member comes into contact with the bearing member and presses substantially in the direction of the rotation axis, thereby restricting the bearing member to a fixed position.
And a preload is applied.

The stationary member is integrated with a base member defining a disk chamber in which the recording disk is stored.
It shall be formed .

[0011]

A screw member is screwed to the other end of the through hole,
Use a method such as filling an adhesive at the screwed portion
The inside and the outside of the through-hole communicating without being substantially closed. In other words, a clamp for holding and fixing the recording disk
By making the mounting hole of the pump member a through hole,
The surface treatment liquid in the holes can be evenly distributed.
In addition to reliably preventing the occurrence of rust,
Lubricant particles of ball bearing inside hub member through through hole
Leakage of dust and dust to the outside (magnetic disk side)
Contamination of the disk chamber can be prevented . Also the through hole
The screw member screwed to the other end of the screw member substantially pushes the side surface of the bearing member in the rotation axis direction by screwing into the through hole. In this case, the screw member restricts the bearing member to a fixed position. This pressing force becomes the required preload of the bearing member and acts continuously. Therefore, the bearing member does not need to be fixed by bonding.

Next, by using the stationary member as a base member for defining a disk chamber for accommodating a recording disk, the number of parts, the number of assembling steps, and the like are reduced, thereby improving productivity.

[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.
In addition, a recording disk 18 having a donut shape is mounted. Three recording disks 18 are sequentially stacked via a spacer 19 and are held by a clamp member 20 provided at the uppermost portion.

The clamp member 20 has a substantially disk shape.
It has a mounting hole 51 provided coaxially with the rotation axis 40 which 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 gives 3
The recording disks 18 are integrally held and fixed to the hub member 1 and are driven to rotate together with the hub member 1.

At the center of the hub member 1, a shaft portion 3 for rotatably supporting the hub member 1 is provided upright.
It is formed coaxially and integrally with 0. A through hole 4 is provided inside the shaft portion 3. The through-hole 4 also extends coaxially with the rotation axis 40, and the clamp member 20 described above is screwed on one end of the through-hole 4 on the mounting side of the recording disk 18, that is, on the upper side in FIG. It has a screw portion 22 to be attached. Take this way
By making the perforated hole 51 into the through hole 4, the surface inside the through hole
Disperse the surface treatment liquid etc. evenly, and ensure the generation of rust etc.
Can be prevented.

A screw portion 26 is provided at the other end of the through hole 4. The screw member 5 is provided with a screw member 5 from the bottom to the top of the figure, that is, the rotation axis 40.
It is screwed upward and upward. The through hole 4 is substantially sealed by the screw member 5. For this reason, dust present inside the spindle motor, lubricant particles scattered from the ball bearings 23 and 24, and the like are effectively prevented from flowing through the through hole 4 and into the disk room space 25 communicating therewith. be able to.

Reference numeral 6 denotes a fixed base of the spindle motor and a bracket which forms a stationary member. The bracket 6 has a substantially shallow dish shape, and a rotation axis 40
A cylindrical portion 10 erected on the same axis is integrally formed. The outer peripheral end 52 of the bracket 6 is fixed to the base member 7. The base member 7 defines a disk chamber in which a recording disk is stored.

The inside of the cylindrical portion 10, that is, the rotation axis 40
A pair of ball bearings 23 and 24 as bearing members are mounted and held on the side 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 an outer peripheral surface 38 of the cylindrical portion 10, and a rotor magnet (field magnet) is opposed to the stator 15 on an inner peripheral surface 39 of the hub member 1. 17 are arranged in a ring shape. The stator 15 and the rotor magnet 17 drive the rotor to rotate relative to each other. 16 is a rotor magnet 17
Is a yoke member.

The labyrinth seal structure is formed by bringing the flange portion 9 of the hub member 1 close to the bottom surface portion 11 and the inner peripheral side surface portion 8 of the bracket 6 to form a labyrinth seal structure. Outflow to the space 25 is prevented. Reference numeral 13 denotes a seal member, which is attached to the bracket 6 to improve airtightness inside the spindle motor.

In the ball bearing 23, its outer ring portion 32
The inner ring portion 30 is positioned and fitted to the inner peripheral surface 34 and the step portion 28 provided on the cylindrical portion 10 of the bracket 6, and the outer peripheral surface 33 and the bottom portion 3 of the shaft portion 3 of the hub member 1.
1 and is fitted. All are fitted with a loose fit. 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 similarly fitted by loose fitting.

Therefore, in this case, the aforementioned screw member 5 is
When the screw member 5 is screwed and screwed into the screw portion 26 of the through hole 4, the side end portion 14 of the screw member 5 becomes 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 upward on the rotation axis 40 in the drawing, so that the side end portion 14
2 is pressed substantially upward in the figure on the axis of rotation 40.
This pressing force generates preloading action lines 36 and 37 shown in the figure for the ball bearings 24 and 23, respectively. As a result, the ball bearings 23 and 24 are preloaded at fixed positions 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 according to the degree of screwing of the screw member 5, so that the preload can be managed freely by adjusting the screwing. And
The preload works continuously. In this way, since a preload can be simultaneously applied at the time of assembling the spindle motor, it is not necessary to apply the adhesive and harden while applying the preload, as compared with the case of using a conventional adhesive. Further, various inconveniences caused by the uncured adhesive do not occur. In addition, the pressing force according to the required preload is set for each type of spindle motor, but the spindle motor of this configuration is very simple because it can be performed only by adjusting the screw advance of the screw member.

Next, an example of the assembling sequence 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 denoted by the same reference numerals. The right half of the figure showing the cross section is omitted. 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 upper side surface in the figure of the inner ring portion 30 is brought into contact with the bottom portion 31 of the hub member 1. Since the fitting is set to loose in advance, the ball bearing 23 is easily fitted. On the other hand, on the bracket 6 side, the stator 15 is mounted on the cylindrical portion 10.

In FIG. 3, the ball bearing 24 is fitted into the cylindrical portion 10 from the bottom to the top in the figure. The ball bearing 24 is provided on the inner peripheral surface 3.
It is positioned and mounted by the step 5 and the step portion 29. 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 is brought into contact with the step portion 28 of the cylindrical portion 10. Thus, 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 as shown by the arrow and screwed. As shown in FIG. 4B, after the side end 14 of the screw member 5 abuts on the side surface (the lower side in the figure) of the inner ring portion 12, the screw member 5 is advanced by a predetermined amount. Add the required preload. Ball bearing 2
Preload action lines 37 and 36 are generated at 3, 24, respectively. 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 common to the spindle motor described in FIG. 1 are denoted by the same reference numerals. Since the description will be duplicated, only 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 50 that defines the disc chamber 25 is provided.
That was the thing. That is, in FIG.
Configuration in which a certain bracket 6 and base member 7 are integrally formed
It is. By the base member 50 and the upper lid 55,
A closed space for accommodating the recording disk 18, that is, a disk chamber 25 is defined. A seal member made of an elastic material is interposed at a joint between the base member 50 and the lid 55. Therefore, according to the present embodiment, the number of parts is reduced, and the assembling becomes easier.

The through hole 4 of the shaft portion 3 is not provided with a screw portion, and a tube member 52 made of a plastic material is inserted instead. Clamp member 20
The mounting screw 21 and the screw member 5 of this tube member 5
The screw 2 is advanced while being screwed. For this reason, a screw portion is not required on the inner peripheral surface 51 of the through-hole 4, so that the penetration of the surface treatment liquid is further facilitated. In addition, the sealing effect of the screw member 5 with respect to the through hole 4 is further improved, and the effect of preventing the screw member 5 from loosening 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 such an embodiment, and various changes and modifications can be made without departing from the scope of the present invention. . For example, although the fixing of the clamp member 20 to the hub member 1 has been described in this embodiment by screwing into the through hole 4, a pin-like mounting tool may be inserted. 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. Further, in the present embodiment, the portion of the ball bearing with which the screw member is abutted has been described with respect to the inner ring portion. However, the ball bearing holding structure may be in contact with the outer ring portion. In addition, 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 recording disk is held by the hub member on which the recording disk is mounted.
The mounting hole of the clamp member to be fixed is a through hole
In this way, the surface treatment liquid etc.
Can be spread over, and the generation of rust etc. can be reliably prevented.
You. In addition, a screw member screwed to one end of the shaft portion of the hub member on which the recording disk is mounted is used as a sealing member for closing the through hole, and the bearing member is restricted to a fixed position.
Thus, a preload applying means for applying a preload is used. For this reason, without using a filler, an adhesive, or the like, there is no need to manage the accompanying quantity and quality. The disadvantages due to uncured adhesive are also eliminated.

Further, by integrating the base member with the accommodating portion accommodating the recording disk, more space saving and downsizing can be achieved, and a spindle motor with high productivity and high reliability can be obtained.

[Brief description of the 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. 1;

FIG. 4 is a sectional view for explaining an assembling order of the spindle motor shown in FIG. 1;

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 symbols]

 DESCRIPTION OF SYMBOLS 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)

(57) [Claims] A hub member for mounting a recording disk, a bearing member, and a stationary member for holding the bearing member;
A spindle motor in which the hub member is driven to rotate relative to the stationary member via the bearing member, wherein the hub member is provided with a through-hole coaxially with a rotation axis, and one end of the through-hole. The recording disk mounting side is a mounting hole for a clamp member for holding and fixing the recording disk. A screw member is screwed to the other end of the through hole, and the through hole is substantially fixed. A spindle motor, wherein the screw member is sealed, and the screw member abuts on the bearing member and is pressed substantially in the direction of the rotational axis, thereby regulating the bearing member to a fixed position and applying a preload. 2. The stationary member is formed integrally with a base member that defines a disk chamber in which the recording disk is stored.
Been, spindle motor according to claim 1, wherein a.