JP3155363B2 - 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 mainly used for rotating a disk (magnetic disk, optical disk) or the like.

[0002]

2. Description of the Related Art In general, a spindle motor has a bracket mounted on a disk drive and a hub as a rotor rotatable relative to the bracket, and a disk is mounted on the hub as required. You.

[0003] For example, FIG. 3 shows a conventional spindle motor, in which a vertical fixed shaft 1 attached to a bracket has a pair of upper and lower bearings 2.
A hub 4 having a substantially inverted bowl shape on which a recording disk is mounted is rotatably mounted through a hub 3, and a stator 5 is fixed between the two bearings 2 and 3 of the shaft 1.
A rotor magnet 6 facing the stator 5 is attached via a yoke 7 to an inner periphery of the rotor magnet 6.

[0004] The hub 4 has an annular step portion 10 formed between an upper bearing mounting position 8 and a lower magnet mounting position 9 on the upper inner periphery thereof. Are smaller than the inner diameter of the magnet mounting position 9. The rotor magnet 6 and the yoke 7 are in contact with the lower surface of the step 10 via a ring 11 for height adjustment.

[0005] A flange 12 on which a disk is placed is provided on the outer periphery of the lower end of the hub 4. The hub 4 is usually made of aluminum or an aluminum alloy, and is formed by so-called shaving. Reference numeral 12 denotes a bush fixed to the inner periphery of the lower end of the hub 4, and the bearing 3 is fixed to the inner periphery of the bush 13.

In the above-described spindle motor, both bearings 2 and 3 use an ultraviolet-curing adhesive or an anaerobic adhesive to connect each inner ring to the shaft 1.
Each outer ring is fixedly attached to the hub 4 and the bush 13.

When the bearings 2 and 3 are fixed by the adhesive, the adhesive holding grooves 14 and 15 formed on the upper and lower peripheral surfaces of the shaft 1, the bearing mounting surface 8 of the hub 4, and the inner peripheral surface of the bush 13. Adhesive holding groove 1 formed in
The applied adhesive is held in each of the bearings 6 and 17, and the inner ring and the outer ring of both bearings 2 and 3 are fixed by curing the adhesive by irradiation of ultraviolet rays or supply of an anaerobic gas, respectively.

[0008]

However, in the conventional spindle motor as described above, especially when the upper bearing 2 is fixed, the adhesive applied to the bearing fixing surface 8 remains uncured while the bearing is fixed. Flows over surface 8,
There are drawbacks such as dripping on the stator 5 and flowing down on the surface of the rotor magnet 6 to cause noise and threading.

In order to solve this problem, for example, FIG.
As shown in FIG.
It is conceivable to form the annular convex portion 18 having a smaller diameter.
According to this, not only can the bearing 2 be positioned by the convex portion 18, but also when the hub 4 is machined, the bearing fixing surface 8 and the convex portion 18 are cut out so that the recess 1
Since 9 is formed, the uncured adhesive can be held in this portion, and the outflow of the adhesive can be prevented.

However, in this configuration, a convex portion 18 must be formed on the inner surface of the hub 4 in addition to the step portion 10.
There is a drawback in that the processing is troublesome and the processing cost is high.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems of the prior art, and it is an object of the present invention to make it easy to manufacture a hub and to make sure that an uncured adhesive flows out. It is another object of the present invention to provide a spindle motor that can prevent the occurrence of a problem.

[0012]

In order to achieve the above object, in a spindle motor according to the present invention, a substantially inverted bowl-shaped hub on which a disk is mounted is provided on the outer periphery of a fixed shaft via a pair of upper and lower bearings. Rotatably mounted, fixing the stator between both bearings of the shaft,
A rotor magnet facing the stator is mounted on the inner periphery of the hub, and the inner periphery of the hub is located between the upper bearing mounting position and the lower magnet mounting position, and the inner diameter of the bearing mounting position is larger than the inner diameter of the magnet mounting position. to form a stepped portion of the annular whose diameter was excised corner of the stepped portion, mounting the lower surface to the inner diameter is for height adjustment of the b over data magnet formed smaller in diameter than the inner diameter of the bearing mounting position ring of the stepped portion, Place the upper bearing on top of the ring,
A space for holding an adhesive for fixing the bearing is formed between the step portion and the ring.

In the spindle motor according to the present invention, a substantially inverted bowl-shaped hub on which a disk is mounted is rotatably mounted on the outer periphery of the fixed shaft via a pair of upper and lower bearings. A spindle motor having a rotor magnet facing the stator mounted on the inner periphery of the hub. The bearing mounting position is located on the inner periphery of the hub between the upper bearing mounting position and the lower magnet mounting position. with the inner diameter to form a stepped portion of the annular whose diameter than the inner diameter of the magnet mounting position, the inner diameter on the lower surface of the step attaches the height ring for adjustment of Russia over data magnet formed smaller in diameter than the inner diameter of the bearing mounting position , the inner peripheral portion upper surface of the ring, and an outer diameter rather slightly smaller <br/> than the inner diameter of the bearing mounting position Bear Forming an annular convex portion projecting ring side, by placing the upper part of the bearing on the upper surface of the ring, to form a holding space for the adhesive for a bearing secured between the corner portion and the annular protruding portion of the stepped portion It is characterized by becoming.

[0014]

In the spindle motor described above, in the former case, the inner diameter of the ring for adjusting the height of the rotor magnet is formed smaller than the inner diameter of the bearing mounting position of the step formed on the hub. This ring allows the positioning of the upper bearing.

The cutout formed at the corner of the step forms a holding space for the bearing fixing adhesive between the step and the ring, so that the adhesive applied to fix the bearing on the ring is formed. Even if the agent flows due to uncuring, the adhesive is held in this holding space and the outflow of the adhesive is reliably prevented.

In the latter case, the bearing for the upper part can be positioned by the ring for adjusting the height of the rotor magnet, and the adhesive holding space is provided between the outer periphery of the annular convex part on the upper surface of the ring and the bearing mounting surface. Is formed, the outflow of the adhesive is reliably prevented by the holding space.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to FIGS. The same reference numerals as those described above indicate the same or corresponding components.

First, FIG. 1 showing the first embodiment will be described. FIG. 1 shows the entire cross-sectional structure of a spindle motor 1 according to the present invention.
An annular cut surface 20 is formed at the corner of the step portion 10 by C-plane processing, and a ring 21 for adjusting the height of the rotor magnet 6 is applied to the inner peripheral surface of the magnet mounting position 9 by the outer peripheral surface.
When contacted, the inner periphery is
The inner diameter is formed smaller than the inner diameter of the bearing mounting surface 8 so as to protrude radially inward from the surface , and the step portion 10 and the ring 2 are formed.
1 is that an adhesive holding space 22 surrounded by the cut surface 20 and the upper surface of the ring 21 is formed.

Therefore, when the adhesive is applied to the bearing mounting surface 16 and the adhesive is hardened by inserting the upper bearing 2, even if the adhesive is not hardened, the adhesive remains in the holding space 22. And the outflow of the adhesive can be reliably prevented.

In addition, since the bearing 2 is mounted on the ring 21, there is an advantage that the positioning of the bearing 2 is realized.

Next, FIG. 2 showing the second embodiment will be described. In this embodiment, the ring 23 for adjusting the height of the rotor magnet 6 is attached to the outer peripheral surface within the magnet mounting position 9.
When it is brought into contact with the peripheral surface, the inner peripheral portion is
From the inner circumferential surface of 4 so as to protrude radially inward, while the inner diameter is formed smaller in diameter than the inner diameter of the base <br/> bearings mounting surface 16, this
Ring 2 protruding from the inner peripheral surface of bearing mounting surface 16
A ring whose outer diameter is smaller than the inner diameter of the bearing mounting surface 16 and protrudes in the axial direction toward the bearing 2
The bulging portion 24 forming a convex shape is integrally formed, and a space 25 for holding the adhesive is formed between the bearing mounting surface 16 on the ring 23 and the outer peripheral surface of the bulging portion 24.

Therefore, in this embodiment, even if the adhesive applied to the bearing mounting surface 16 is uncured, the adhesive is held in the holding space 25 and the outflow of the adhesive is ensured, as described above. In addition, since the bearing 2 is mounted on the ring 23, the positioning of the bearing 2 is realized.

[0023]

Since the present invention is configured as described above, the following effects can be obtained.

[0024] In the spindle motor of claim 1 wherein, the ring for height adjustment of the rotor magnet, and a diameter smaller than the inner diameter of the bearing mounting position of the stepped portion formed in the inner diameter <br/> hub Because of this, the upper bearing can be positioned by this ring, and furthermore, a cutout formed at the corner of the step can form a holding space for the adhesive for fixing the bearing between the step and the ring, Even if the adhesive applied to fix the upper bearing flows due to uncuring, the adhesive can be held in this holding space and the adhesive can be reliably prevented from flowing out, making processing of the hub complicated. Not even.

In the spindle motor according to the present invention, the bearing for the upper portion can be positioned by the ring for adjusting the height of the rotor magnet, and the adhesive for fixing the bearing can be formed without forming a cut surface or the like at the step portion. A space for holding the agent can be formed, and the adhesive can be reliably prevented from flowing out with a simple configuration.

[Brief description of the drawings]

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

FIG. 2 is a sectional view showing a part of a second embodiment of the spindle motor according to the present invention.

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

FIG. 4 is a partial sectional view of another conventional spindle motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shaft 2, 3 Bearing 4 Hub 5 Stator 6 Rotor magnet 8 Bearing mounting surface 9 Magnet mounting surface 10 Step 20 Cutting surface 21, 23 Ring 22, 25 Holding space 24 Swelling portion

Claims (2)

(57) [Claims] 1. A substantially inverted bowl-shaped hub on which a disk is mounted is rotatably mounted on the outer periphery of a fixed shaft via a pair of upper and lower bearings, and a stator is fixed between the two bearings of the shaft. A spindle motor comprising a hub and a rotor magnet opposed to the stator mounted on an inner periphery of the hub, wherein the inner periphery of the hub is located between an upper bearing mounting position and a lower magnet mounting position; with an inside diameter to form a stepped portion of the annular whose diameter than the inner diameter of the magnet mounting position, excised corner of the stepped portion, the inner diameter on the lower surface of the stepped portion is formed smaller in diameter than the inner diameter of the bearing mounting position mounting height ring for adjustment before Symbol rotor magnet, by placing the upper portion of the bearing on the upper surface of said ring, said stepped portion Spindle motor, wherein said that by forming a holding space of the bearing fixing of adhesive between the serial ring. 2. A generally inverted bowl-shaped hub on which a disk is mounted is rotatably mounted on the outer periphery of a fixed shaft through a pair of upper and lower bearings, and a stator is fixed between the two bearings of the shaft. A spindle motor having a rotor magnet opposed to the stator mounted on an inner periphery of a hub, wherein an inner diameter of the bearing mounting position is located between an upper bearing mounting position and a lower magnet mounting position on the inner circumference of the hub. ring but form a stepped portion of the annular whose diameter than the inner diameter of the magnet mounting position, for height adjustment of the front SL rotor magnet inner diameter on the lower surface of the stepped portion is formed smaller in diameter than the inner diameter of the bearing mounting position the is attached to the inner peripheral portion upper surface of said ring, and said base outer diameter rather slightly smaller than the inner diameter of the bearing mounting position On the ring side
Forming a projecting annular projection , arranging the upper bearing on the upper surface of the ring,
A spindle motor, wherein a space for holding the bearing fixing adhesive is formed between the projection and the projection .