JPH05161328A - Disk driving apparatus - Google Patents

Abstract

PURPOSE:To obtain a disk driving apparatus which can be thinned and miniaturized by arranging a structure in which the inner diameter circumference of the surface of the rotor yolk is coupled to the rotational shaft by a laser welding, a spot welding, or the like. CONSTITUTION:An extrusion 15 is formed on the inner diameter circumference of the reverse side of a rotor yolk 2 to abut upon the end of the inner lace of a ball bearing 3. A recess 16 is formed in a part facing the extrusion 15. The fitting part to the rotational shaft 1 is welded from the recess 16 side to couple it to the rotational shaft 1. Then, the extrusion 15 abuts on the end face of the bearing 3 to give a pre-load, and at the same time, eliminate the surface deflection of the rotor yolk 2 with respect to the rotational shaft 1 because of the contact with the end face of the bearing 3. The recess 16 on the opposite end to the extrusion 15 can prevent the surface precision from becoming inferior due to the welding by shortening the coupling length to the rotational shaft 1 of the rotor yolk 2. As a result, there is no need for securing any excessive part for pressure fit or contact in the axial direction, making it possible to significantly reduce the thickness of the rotor yolk 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive device for rotating a disk for recording and reproduction.

[0002]

2. Description of the Related Art A recording / reproducing apparatus which uses a magnetic disk or the like as a recording medium and records / reproduces information on / from the disk is an information recording / reproducing apparatus using a magnetic head or the like while rotating a disk mounted in a disk drive unit. Is configured to do. In the disk drive device, a disk-shaped disk-shaped rotor yoke (direct drive) or a pulley (belt drive) is fixed to a rotating shaft, and the rotor yoke or the rotor yoke is provided by an exciting coil or another drive source provided on the stator side. It is configured to rotationally drive the pulley.

[0003]

By the way, in the conventional disk drive device, as a method of fixing the rotor yoke or the pulley to the rotating shaft, a press-fitting margin or a bonding margin is secured in the center hole of the rotor yoke or the pulley. The method of press-fitting or adhering the central hole to the rotary shaft is adopted. However, in such a conventional fixing method, it is necessary to take a long press-fitting or bonding allowance in order to secure the press-fitting strength or the adhesive strength, which increases the thickness of the entire device, and makes it thinner and smaller. There was a problem that it became difficult. Conversely, if the rotor yoke or pulley is made thinner to make the device thinner and more compact, it is necessary to increase the tightening allowance (press-fitting tightness). There is a technical problem that the rotor yoke or pulley has a large surface wobbling, which causes surface wobbling on a disk as a recording medium.

The present invention has been made in view of the above-mentioned conventional technical problems, and an object of the present invention is to improve the surface runout accuracy of a disk and thin the rotor yoke or pulley to make the apparatus thinner. Another object of the present invention is to provide a disk drive device that can be downsized.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a disk drive device in which a disk-shaped rotor yoke for mounting a disk is fixed to a rotating shaft, and the rotor yoke is rotationally driven by an exciting coil provided on the stator side. Around the inner diameter of the rear surface of the rotor, a convex portion that contacts the end surface of the bearing for supporting the rotating shaft is formed, and the periphery of the inner surface of the rotor yoke is joined to the rotating shaft by welding such as laser welding or spot welding. By doing so, the above object is achieved.

According to another aspect of the present invention, in a disc drive device in which a disc-shaped disc mounting pulley is fixed to a rotary shaft and the pulley is rotatably driven via a belt, the disc is rotated around the inner diameter of the back surface of the pulley. The above object is achieved by forming a convex portion that comes into contact with the end surface of the shaft supporting bearing, and connecting the periphery of the inner diameter of the surface of the pulley to the rotating shaft by welding such as laser welding or spot welding. It is a thing.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a vertical cross-sectional view showing an embodiment of a disk drive device to which the present invention is applied, FIG. 2 is a partial vertical cross-sectional view showing a main part of the disk drive device of FIG. 1, and FIG. 3 is a partial plan view seen from the line 3-3 in FIG. In FIG. 1, a housing 10 is fixed to the center of a stator 9, and an upper bearing (ball bearing) 3 and a lower bearing (slide bearing) 6 are positioned and fixed in the housing 10. The rotary shaft 1 is rotatably supported by the bearing 3 and the slide bearing 6.

In FIG. 1, an exciting coil 5 is attached to the upper surface of the stator 9 around the housing 10 via an insulating sheet 8. A circuit board (PCB) 7 is attached to the housing 10. On the other hand, a disc-shaped rotor yoke 2 is fixed to the upper portion of the rotary shaft 1 (the portion protruding from the upper bearing 3). The rotor yoke 2 is fixed to the rotary shaft 1 by laser-welding or spot-welding the central fitting hole portion to the rotary shaft 1.

A magnet 4 is fixed to the back surface (lower surface) of the rotor yoke 2. Further, on the surface (upper surface) of the rotor yoke 2, an attracting magnet 11 for removably positioning and holding a disk (not shown) by a magnetic attracting force is provided. Further, a Teflon tape 12 for protecting the magnetically attracted disk is bonded to the surface of the rotor yoke 2. Thus
A disk drive device is configured in which a disk-shaped rotor yoke 2 for mounting a disk is fixed to a rotating shaft 1, and an exciting coil 5 provided on the stator 9 side drives the rotor yoke 2 to rotate.

That is, the magnet 4 of the rotor yoke 2 sandwiches the circuit board 7, and the exciting coil 5
It is attached to the position corresponding to and the exciting coil 5 →
A magnetic flux path circulating from the stator 9 → the housing 10 → the rotor yoke 2 → the magnet → the exciting coil 5 is formed,
A disk drive device is configured to rotate the rotor yoke 2 by an electromagnetic force when a pulse voltage is applied to the exciting coil 5 and rotationally drive a disk (not shown) on the rotor yoke 2.

In FIGS. 2 and 3, around the inner diameter of the back surface of the rotor yoke 2, there is a convex portion 1 that comes into contact with the end surface of the inner race of the ball bearing 3 during assembly.
5 is formed, and a concave portion 14 is formed in a portion of the surface of the rotor yoke 2 corresponding to the convex portion 15. Therefore, the rotor yoke 2 is joined to the rotary shaft 1 by laser welding or spot welding the fitting portion with the rotary shaft 1 from the concave portion 16 side. Reference numeral 14 in FIGS. 2 and 3 indicates the position of the laser welding or spot welding.

The convex portion 15 provided on the fixed portion of the rotor yoke 2 comes into contact with the end surface of the bearing 3 (the end surface of the inner race) to apply a preload to the bearing 3, and also comes into contact with the end surface of the bearing 3. Is for eliminating the surface runout of the rotor yoke 2 with respect to the rotating shaft 1. Further, the concave portion 16 of the rotor yoke 2 opposite to the convex portion 15 reduces the fitting length of the rotor yoke 2 with the rotating shaft 1 to prevent the deterioration of the surface accuracy (surface runout) caused by welding. It is also for doing.

According to the embodiment described above, the convex portion 15 that abuts the end surface of the bearing 3 on the back surface of the rotor yoke 2.
Since the concave portion 16 formed on the opposite side is welded to the rotary shaft 1 by laser welding or spot welding, it is not necessary to secure a press-fitting margin and a bonding margin in the axial direction as in the conventional case. Therefore, the thickness of the rotor yoke 2 can be greatly reduced, and an ultrathin disk drive device can be configured.

In the illustrated embodiment, the case of a direct drive type disk drive device in which the rotor yoke 2 is fixed to the rotary shaft 1 has been illustrated, but the present invention replaces the rotor yoke 2 with another drive device. The same can be applied to a disk drive device in which a disk-shaped pulley, which is rotationally driven by a power source via a belt, is fixed to the rotary shaft 1, that is, a belt drive type disk drive device. Is what you get.

[0015]

As is apparent from the above description, according to the present invention, a disk-shaped rotor yoke for mounting a disk is fixed to a rotating shaft, and the rotor yoke is rotationally driven by an exciting coil provided on the stator side. In the driving device, a convex portion that is in contact with the end face of the bearing for supporting the rotating shaft is formed around the inner diameter of the back surface of the rotor yoke, and the periphery of the inner surface of the rotor yoke is laser-welded or spot-welded to the rotating shaft. Since it is configured to be joined by welding, the disc drive device is provided in which the surface wobbling accuracy of the disc is improved and the rotor yoke is thinned to further reduce the thickness and size of the device.

According to another aspect of the present invention, in a disc drive device in which a disc-shaped disc mounting pulley is fixed to a rotating shaft and the pulley is rotatably driven by a belt, the disc drive device is provided around the inner diameter of the back surface of the pulley. Since the convex portion that comes into contact with the end face of the bearing for supporting the rotating shaft is formed and the periphery of the inner diameter of the surface of the pulley is joined to the rotating shaft by welding such as laser welding or spot welding, the surface wobbling of the disk (EN) Provided is a disk drive device capable of further improving the accuracy and thinning the pulley to further reduce the device thickness and size.

[Brief description of drawings]

FIG. 1 is a central longitudinal sectional view schematically showing the configuration of an embodiment of a disk drive device to which the present invention is applied.

2 is a partially enlarged vertical cross-sectional view showing a configuration of a rotor yoke fixing portion of the disk drive device shown in FIG.

FIG. 3 is a partially enlarged plan view taken along the line 3-3 in FIG.

[Explanation of symbols]

 1 rotating shaft 2 rotor yoke 3 bearing 4 magnet 5 exciting coil 6 sliding bearing 7 circuit board 8 insulating sheet 9 stator 10 housing 11 suction magnet 12 Teflon tape 14 laser welding or spot welding position 15 convex portion of rotor yoke 16 rotor yoke Recess

Claims (2)

[Claims] 1. A disk drive device in which a disk-shaped rotor yoke for mounting a disk is fixed to a rotating shaft, and the rotor yoke is rotationally driven by an exciting coil provided on the stator side, in the vicinity of the inner diameter of the back surface of the rotor yoke.
A disk drive device, characterized in that a convex portion that comes into contact with an end surface of a bearing for supporting a rotating shaft is formed, and the periphery of the inner surface of the rotor yoke is joined to the rotating shaft by welding such as laser welding or spot welding. 2. A disk drive device in which a disk-shaped pulley for disk mounting is fixed to a rotary shaft and the pulley is rotatably driven by a belt, wherein an end surface of a bearing for supporting the rotary shaft is provided around an inner diameter of a back surface of the pulley. A disk drive device, characterized in that a convex portion that comes into contact with is formed, and the periphery of the inner diameter of the surface of the pulley is joined to the rotating shaft by welding such as laser welding or spot welding.