JP2003289644A - Spindle motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable slippage stop of a rotor easily using a simple constitution in a spindle motor, and to shorten the axial length of the motor. <P>SOLUTION: In a spindle motor 21, where a rotary shaft 25 is set freely rotatably in bearings 22 and 23 retained by a bearing holder 24, and also a rotor yoke 10 is set on the rotary shaft 25 and beside a drive magnet 12 is arranged on the rotor yoke 10 and further a stator 16 with a coil 15 wound on a core 14 is set to the periphery of the bearing holder 24, the bearings 22 and 23 are arranged two pieces a specified interval A apart above and below; and also a circular groove 25a is made in the space A between the bearings 22 and 23 around the rotary shaft 25, and a slippage stop washer 26 is fitted in the position of the circular groove 25a and the space A between those bearings 22 and 23 thereby regulating the axial displacement of the rotary shaft 25. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor, and in particular, in a drive spindle motor for a CD-ROM disc or the like, it is possible to easily prevent the rotor from coming off, and at the same time, in the axial direction of the motor. The present invention relates to a spindle motor whose length is shortened.

[0002]

2. Description of the Related Art A conventional spindle motor of this type will be described with reference to FIGS. In FIG. 2, reference numeral 1 is a spindle motor, and the spindle motor 1 is supported by a bearing holder 3 which is erected on the upper surface of a base 2 and is provided with a bearing 4, and a rotary shaft 5 is rotatably attached to the bearing 4. It is fitted loosely.

The lower end of the rotary shaft 5 is brought into contact with a thrust board 6 attached to the lower end of the bearing holder 3 via a thrust washer 7, and the rotary shaft 5
An annular groove 5a formed on the outer periphery near the lower end of the bearing holder 3 is engaged with a bottom opening 8a of a bottomed cylindrical stopper 8 mounted near the lower end of the bearing holder 3, and the axial direction of the rotary shaft 5 Displacement is regulated.

Further, a bottomed cylindrical rotor yoke 10 which constitutes the rotor 9 is fitted in the vicinity of the upper end of the rotary shaft 5 via a bush 11, and the drive magnet 12 is provided along the inner peripheral surface of the rotor yoke 10. , And a turntable 13 for fixedly holding a CD-ROM or the like is fixed to the upper end of the rotary shaft 5.

A stator 16 having a coil 15 wound around a core 14 is fitted on the outer peripheral surface of the bearing holder 3. In FIG. 3, 17 is another spindle motor, and the spindle motor 17 is the spindle motor 1
2, a rotary shaft 18 without an annular groove 5a is provided in place of the rotary shaft 5 of the spindle motor 1 shown in FIG. 2, and a stopper 8 is attached to the lower end in place of the bearing holder 3. Instead, a bearing holder 19 having an outward flange 19a extending from the upper end is provided.

Further, a dish-shaped locking body 20 having an opening bottom plate 20a is attached to the center of the inner surface of the bottom plate 10a of the rotor yoke 10 with the flange 20b of the locking body 20 fixedly attached. There is. Then, the upper end portion of the bearing holder 19 penetrates the opening of the bottom plate portion 20a of the locking body 20, and the outward flange 19a of the bearing holder 19 is loosely fitted on the upper surface of the bottom plate portion 20a, whereby the rotor is rotated. It functions to prevent the yoke 10 from coming off.

[0007]

In the spindle motor of the above-mentioned conventional example, the bottom portion of the bottomed cylindrical stopper mounted near the lower end portion of the bearing holder in the annular groove formed on the outer periphery near the lower end portion of the rotary shaft. The openings are configured to engage with each other, whereby the axial displacement of the rotary shaft is regulated and the rotor is prevented from coming off.

In another spindle motor, the upper end of the bearing holder penetrates the opening of the bottom plate of the locking body, and the outward flange of the bearing holder is loosely fitted on the upper surface of the bottom plate. , Plays the function of preventing the rotor yoke from coming off. However, each of the spindle motors has a drawback that the axial length of the spindle motor is relatively long due to the above-mentioned configuration for preventing the rotor from coming off. It's complicated.

Therefore, in the spindle motor, there arises a technical problem to be solved in order to easily prevent the rotor from coming off with a simple structure and to shorten the axial length of the rotor. Therefore, an object of the present invention is to solve this problem.

[0010]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above-mentioned object, and a rotary shaft is rotatably loosely fitted in a bearing held by a bearing holder and the rotary shaft is attached to the rotary shaft. A spindle motor in which a rotor yoke is fitted, a drive magnet is arranged on the rotor yoke, and a stator having a coil wound around a core is fitted on an outer peripheral surface of the bearing holder. The two bearings are arranged vertically with a predetermined gap between them, and an annular groove is formed at a gap position of the bearing on the outer peripheral portion of the rotary shaft, and a retaining washer is fitted in the annular groove and the gap of the bearing. And a spindle motor configured to restrict axial displacement of the rotating shaft, and a spindle motor in which the annular groove is formed at an axial center position of the bearings arranged above and below. It is intended to provide.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to FIG. For convenience of description, the same components as those of the conventional example will be designated by the same reference numerals and the description thereof will be omitted. In FIG. 1, reference numeral 21 is a spindle motor which is a modification of the conventional spindle motor (1 in FIG. 2). The spindle motor 21 is vertically spaced by a predetermined gap A and has the same axial length. The two bearings 22, 23 are held and arranged by the bearing holder 24, and the rotary shaft 25
An annular groove 25a having substantially the same width as the gap A is formed at a position corresponding to the gap A between the bearings 22 and 23 on the outer peripheral portion of the bearings 22, 23 arranged above and below the annular groove 25a.
Is formed at the center position in the axial direction, and a retaining washer 26 is fitted in the position of the gap A between the annular groove 25a and the bearings 22 and 23 to regulate the axial displacement of the rotating shaft 25 and the rotor 9. It is configured.

The lower end of the rotary shaft 25 is not formed with a conventional annular groove (5a in FIG. 2), and the bearing holder 24 is provided with a conventional stopper (8 in FIG. 2). ) Cannot be installed. Since the annular groove 25a is formed to have a relatively narrow width for the washer 26 to be fitted therein, the total length of the rotary shaft 25 can be made shorter than that of the conventional rotary shaft. Become.

Therefore, in the spindle motor 21, the rotary shaft 25 is shorter than the rotary shaft of the conventional spindle motor, and the axial length of the spindle motor 21 is shorter than that of the conventional spindle motor. Further, the spindle motor 21 uses a retaining washer 26,
Since the rotation shaft 25 and the rotor 9 are prevented from coming off, it is possible to easily prevent the rotor 9 from coming off with a simple configuration.

Further, since the annular groove 25a is formed at the axial center position of the bearings 22 and 23 arranged above and below, the effect that the rotation of the rotary shaft 25 becomes stable when the rotary shaft 25 rotates. There is. The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified one.

[0015]

As described in detail in the above one embodiment, the present invention according to claim 1 is a spindle motor, in which two bearings are arranged vertically with a predetermined gap therebetween and are rotated. An annular groove is formed at a gap position of the bearing on the outer peripheral portion of the shaft, and a retaining washer is fitted in the gap between the annular groove and the bearing so as to regulate the axial displacement of the rotating shaft. The rotation shaft and the rotor can be prevented from coming off, and the rotation shaft can be made shorter than the rotation shaft of the conventional spindle motor, so that the axial length of the spindle motor can be shortened. it can. In addition, because it uses a retaining washer to prevent retention,
With a simple structure, you can easily prevent the rotor from coming off.

In the invention according to claim 2, since the annular groove is formed at the axial center position of the bearings arranged above and below, in addition to the effect of the invention according to claim 1, It is an invention that has a very significant effect such as stable rotation.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a spindle motor showing an embodiment of the invention.

FIG. 2 is a vertical sectional view of a spindle motor showing a conventional example.

FIG. 3 is a longitudinal sectional view of another spindle motor showing a conventional example.

[Explanation of symbols]

21 Spindle motor 22,23 bearing 24 bearing holder 25 rotation axis 25a annular groove 26 retaining washer

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J037 AA08 BA01 BB07 JA03 JA12                 5H605 AA04 BB05 BB19 CC04 CC05                       DD05 EB03 EB06 EB37 EB38

Claims (2)

[Claims] 1. A rotary shaft is rotatably loosely fitted to a bearing held by a bearing holder, a rotor yoke is fitted to the rotary shaft, and a drive magnet is arranged on the rotor yoke. In a spindle motor in which a stator having a coil wound around a core is fitted to the outer peripheral surface of the bearing holder, two bearings are arranged vertically with a predetermined gap therebetween, and the outer periphery of the rotary shaft is arranged. An annular groove is formed at a gap position of the bearing of the bearing portion, and a retaining washer is fitted in the gap between the annular groove and the bearing to restrict axial displacement of the rotary shaft. Spindle motor. 2. The spindle motor according to claim 1, wherein the annular groove is formed at an axial center position of the bearings arranged above and below.