JPH07169182A - Magnetic disk driving device - Google Patents

Abstract

PURPOSE:To prevent the generation of burrs of inner peropheral surface of ball receptors of a hub and to improve the roundness of the inner circumferential surface of the hub by fixing inner races to a fixed axis and outer races to the hub respectively and providing adhesive packing grooves on prolonged lines connecting points where the balls of the hub are in contact with the inner races and points where the balls are in contact with the outer races. CONSTITUTION:Inner races 4 and outer races 5 are fixed respectively to a fixed axis 1 and a hub 2. The hub 2 is supported rotatively to the fixed axis 1 with two pieces of ball bearings 3. The adhesive packing groove 12 of the fixed axis 1 and the adhesive packing grooves 13 of the hub 2 are formed on the prolonged lines connecting contaction points where the balls 6 of the bearing are in contact with the inner races 4 and contaction points where the halls 6 are in contact with the outer races 5. As a result, burrs are not generated in the inner circumferential surfaces of the hub 2 at the time of forming grooves 12, 13. Thus, roundness of the inner surface of the hub is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk drive device for rotationally driving various magnetic recording media.

[0002]

2. Description of the Related Art For example, a structure shown in FIG. 3 is known as a magnetic disk drive device for rotationally driving a magnetic disk composed of a disk-shaped recording medium such as a hard disk. A hub 22 for mounting a magnetic disk on an outer peripheral surface 22A is rotatably supported by a fixed shaft 21 via two ball bearings 23. The ball bearings 23 are fixed to the outer peripheral surface of the inner ring 2 along the fixed shaft 21 by adhesion.
4, an outer ring 25 opposed to each inner ring 24 and fixed to the inner peripheral surface of the hub 22 by adhesion, each inner ring 24 and outer ring 2
It is composed of a ball 26 inserted between the four.

A stator 27, which comprises a stator core 28 and a stator coil 29 wound around the stator core 28, is attached below the outer peripheral surface 22A of the hub 22 and around the fixed shaft 21. Also, hub 2
A support member 31 to which a rotor magnet 30 is fixed is attached to a position immediately below the outer peripheral surface 22 </ b> A of 2 so as to face the stator core 28 of the stator 27. further,
Adhesive filling grooves 32 for accumulating the adhesive are provided at positions facing the balls 26 on the inner peripheral surface of the fixed shaft 21 and the inner peripheral surface of the hub 22, which fix the inner ring 24 and the outer ring 25 by adhesion, respectively.
33 is formed. These adhesive filling grooves 32, 33
Is formed by cutting the members constituting the fixed shaft 21 and the hub 22 with a cutting tool.

FIG. 5 shows another conventional example, in which the same parts as those in FIG. 3 are designated by the same reference numerals. In this example, the adhesive to be formed on the outer peripheral surface of the fixed shaft 21 and the inner peripheral surface of the hub 22 respectively. This shows a structure in which the agent filling grooves 32 and 33 are formed at two positions corresponding to the upper and lower positions of the ball 26.

In each of these structures, the stator 27
When the stator coil 29 is energized, the hub 22 receives a rotational force due to the action of the current flowing through the stator coil 29 and the magnetic field generated from the rotor magnet 30, so that the hub 22 can freely rotate with respect to the fixed shaft 21 via the ball bearing 23. Can be rotated. Therefore, the magnetic disk is also rotated integrally with the hub 22.

[0006]

By the way, in the conventional magnetic disk drive, burrs are generated on the inner peripheral surface of the hub when the adhesive filling groove is formed, so that the circularity of the inner peripheral surface of the hub is lowered. However, there is a problem that the rotational accuracy of the ball bearing is deteriorated. That is, as shown in the enlarged view of the portion A of FIGS. 3 and 5 in FIG. 4, when forming the adhesive filling groove 33 on the hub 22 with a cutting tool, a burr 35 is generated in the moving direction of the cutting tool. become. As a result, the circularity of the inner peripheral surface of the hub 22 is lowered, and the outer ring 25 is deformed and distorted, which causes NRRO and the like. Therefore, data read and write errors of the magnetic disk device occur. Resulting in.

The present invention has been made to solve the above problems, and prevents burrs from being generated on the inner peripheral surface of the hub during formation of the adhesive filling groove, thereby forming a perfect circle on the inner peripheral surface of the hub. It is an object of the present invention to provide a magnetic disk drive device which is improved in speed.

[0008]

In order to achieve the above object, the present invention according to claim 1 provides a hub for mounting a magnetic disk on an outer peripheral surface, a fixed shaft, and an adhesive for the fixed shaft and the hub. A magnetic disk drive device comprising: a filling groove; and two ball bearings each having an inner ring fixed to a fixed shaft, an outer ring fixed to a hub, and rotatably supporting the hub with respect to the fixed shaft. Each of the adhesive filling grooves is formed so that the adhesive filling groove of the fixed shaft and the adhesive filling groove of the hub are located on the extension line of the line connecting the contact point of the ball and the contact point of the outer ring of the ball. It is characterized by.

According to a second aspect of the present invention, in the first aspect, the adhesive filling groove is formed at diagonal corner portions of the inner ring and the outer ring of the ball bearing.

According to a third aspect of the present invention, in the first aspect, the adhesive filling grooves of the two ball bearings are formed at different corners of the upper and lower ball bearings along the fixed shaft. To do.

[0011]

According to the structure of the present invention according to claim 1, the inner ring is fixed to the fixed shaft, the outer ring is fixed to the hub, and the balls of the two ball bearings that rotatably support the hub with respect to the fixed shaft come into contact with the inner ring. By forming each adhesive filling groove so that the adhesive filling groove of the fixed shaft and the adhesive filling groove of the hub are located on the extension line of the line connecting the point and the point where the outer ring of the ball contacts No burr is generated on the inner peripheral surface of the hub when the adhesive filling groove is formed. Therefore, the roundness of the inner peripheral surface of the hub can be improved.

According to the configuration of the present invention according to claim 2,
Since the adhesive-filled groove is formed at diagonal corners of the inner ring and the outer ring of the ball bearing, the same operation as in claim 1 is performed.

According to the configuration of the present invention according to claim 3,
Since the adhesive filling grooves of the two ball bearings are formed at different corners of the upper and lower ball bearings along the fixed shaft, the same operation as in claim 1 is performed.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a half sectional view showing an embodiment of a magnetic disk drive device according to the present invention. Reference numeral 1 is a fixed shaft, 2 is a hub for mounting a magnetic disk on an outer peripheral surface 2A, and two balls are provided for the fixed shaft 1. It is rotatably supported via a bearing 3. Ball bearing 3
Is an inner ring 4 fixed to each outer peripheral surface along the fixed shaft 1 by adhesion, an outer ring 5 fixed to each inner peripheral surface of the hub 2 facing each inner ring 4 by adhesion, each inner ring 4 and an outer ring. It is composed of balls 6 inserted between 5.

Reference numeral 7 denotes a stator mounted below the outer peripheral surface 2A of the hub 2 and at a peripheral position of the fixed shaft 1. The stator 7 includes a stator core 8 and a stator coil 9 wound around the stator core 8. It consists of and. Reference numeral 10 denotes a rotor magnet that is arranged so as to face the stator core 8 of the stator 7, and is an outer peripheral surface 2A of the hub 2.
Is attached to a position directly below the support member 11 via a support member 11.

Reference numeral 12 is an adhesive filling groove formed on the outer peripheral surface of the fixed shaft 1, and 13 is an adhesive filling groove formed on the inner peripheral surface of the hub 2, both of which are formed by cutting with a cutting tool. Each of the adhesive filling grooves 12 and 13 is formed so as to be located on an extension line 14 of a line connecting a point where the ball 6 of the ball bearing 3 contacts the inner ring 4 and a point where the ball 6 contacts the outer ring 5. To be done. In the case of this example, the adhesive filling grooves 12 and 13 are formed at diagonal corners of the inner ring 4 and the outer ring 5, respectively, at different corners of the upper and lower ball bearings 3. Its extension 1
The position on 4 corresponds to the contact direction of the ball 6 when preload is applied to the ball bearing 3, and is the direction in which the force is further received. FIG. 2 shows an enlarged view of the portion A of FIG.
2 and 13 show enlarged structures of each adhesive filling groove 1
By forming 2 and 13 at such positions, it is possible to prevent the occurrence of burrs as in the conventional case. That is, it is possible to prevent burrs from being generated on the inner peripheral surface of the hub 2 when the adhesive filling groove 13 is formed.

In such a structure, when the stator coil 9 of the stator 7 is energized, the hub 2 receives a rotational force due to the action of the current flowing through the stator coil 9 and the magnetic field generated from the rotor magnet 10, so that the fixed shaft is fixed. It is possible to freely rotate with respect to 1 via the ball bearing 3. Therefore, the magnetic disk is also driven to rotate integrally with the hub 2.

As described above, according to this embodiment, the inner ring 4 is fixed to the fixed shaft 1 and the outer ring 5 is fixed to the hub 2, and the balls 6 of the two ball bearings 3 for rotatably supporting the hub 2 with respect to the fixed shaft 1. And inner ring 4
So that the adhesive filling groove 12 of the fixed shaft 1 and the adhesive filling groove 13 of the hub 2 are located on the extension line 14 of the line connecting the contact point of the ball 6 and the contact point of the outer ring 5 of the ball 6. By forming the adhesive filling grooves 12 and 13, the adhesive filling groove 1 is formed.
No burr is generated on the inner peripheral surface of the hub 2 when forming the hubs 2 and 13.
Therefore, the roundness of the inner peripheral surface of the hub can be improved.
Further, since the position on the extension line 14 corresponds to the contact direction of the ball 6 when the ball bearing 3 is preloaded, the influence of the adhesive on the ball bearing 3 can be eliminated. Therefore, the inner ring 4 and the outer ring 5 are not deformed or distorted, and do not cause NRRO or the like. Therefore, data reading and writing errors of the magnetic disk device do not occur.

[0019]

As described above, according to the present invention, the inner ring is fixed to the fixed shaft, the outer ring is fixed to the hub, and the balls of the two ball bearings that rotatably support the hub with respect to the fixed shaft come into contact with the inner ring. Each adhesive filling groove is formed so that the adhesive filling groove of the fixed shaft and the adhesive filling groove of the hub are located on the extension line of the line connecting the point and the point where the outer ring of the ball contacts. Therefore, no burr is generated on the inner peripheral surface of the hub when the adhesive filling groove is formed, so that the roundness of the inner peripheral surface of the hub can be improved.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of a magnetic disk drive device of the present invention.

FIG. 2 is an enlarged view showing a main part of FIG.

FIG. 3 is a half sectional view showing a conventional example.

FIG. 4 is an enlarged view showing a main part of FIGS. 3 and 5.

FIG. 5 is a half sectional view showing another conventional example.

[Explanation of symbols]

1 Fixed shaft 2 Hub 3 Ball bearing 4 Inner ring 5 Outer ring 6 Ball 12 Adhesive filling groove formed on outer peripheral surface of fixed shaft 1 13 Adhesive filling groove formed on inner peripheral surface of hub 2 Ball 6 and inner ring 4 contact An extension of the line connecting the point to be made and the point where the ball 6 and the outer ring 5 contact

Claims (3)

[Claims] 1. A hub for mounting a magnetic disk on an outer peripheral surface thereof, a fixed shaft, an adhesive filling groove formed in the fixed shaft and the hub, and an inner ring fixed to the fixed shaft and an outer ring fixed to the hub. In a magnetic disk drive including two ball bearings that rotatably support the hub with respect to the above, on the extension line of the line connecting the point where the ball of the ball bearing contacts the inner ring and the point where the outer ring of the ball contacts. A magnetic disk drive device, wherein each adhesive filling groove is formed so that the adhesive filling groove of the fixed shaft and the adhesive filling groove of the hub are positioned. 2. The magnetic disk drive device according to claim 1, wherein the adhesive filling groove is formed at diagonal corners of the inner ring and the outer ring of the ball bearing. 3. The magnetic disk drive device according to claim 1, wherein the adhesive filling grooves of the two ball bearings are formed at different corners of the upper and lower ball bearings along the fixed shaft.