JPH0730570U - Spindle motor for disk drive - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the processing cost and make it easier to reduce the size and thickness. [Structure] A bearing holder mounting hole 14 having a step portion 13 is formed in the center of a stator base 12 made of a magnetic metal plate. The cylindrical bearing holder 20 having the brim 21 in the bearing holder mounting hole is attached so that the brim 21 is locked to the step portion. Preferably, the brim 21 is slightly smaller than the thickness of the step portion 13. [Effect] Since a large amount of leakage magnetic flux can be picked up by the stator base made of a magnetic metal plate, the position detecting element can be made small, which contributes to downsizing and thinning of the motor.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spindle motor for driving a disc used in a CD player, a CD-ROM, etc., and relates to an improvement in an assembly structure of a stator base and a bearing holder.

[0002]

[Prior art]

 A cored type DC brushless motor as a conventional disk driving spindle motor is generally as shown in FIG. That is, the stator base 1 is integrally formed with the bearing holder 2 by aluminum or zinc die-cast molding, and the mounting surface 5 is cut to obtain the axial straightness based on the inner diameter where the bearings 3 and 4 are arranged. ing.

In the figure, 5 is a stator core around which an armature coil 6 is wound, and is fitted to the bearing holder 2. Reference numeral 7 denotes a shaft rotatably arranged on the bearing, the base end of which is pivotally supported by the outer case 8 via a slider 9. The outer case 8 is held by crimping the opening edge to the stator base 1. Further, between the outer case 8 and the stator core 5, an inner case 10 that faces the stator core 5 with a small gap between the ring-shaped magnets M is housed, and the bearings 7a and 7a are fixed to the shaft 7 at the bottom center. It is freely rotatable through. F is a flexible circuit board attached to the stator base 1.

[0004]

[Problems to be solved by the device]

 However, since the motor of such a configuration is a non-magnetic die-cast stator base as described above, it is necessary to cut the mounting surface based on this inner diameter to make the axis straight after machining the inner diameter. Has become a serious problem. Moreover, since it is a non-magnetic material, leakage flux and the like are generated, and the magnetic flux to the position detecting element 11 is difficult to be corrected and the size of the large position detecting element 11 becomes large in order to increase the sensitivity, which is disadvantageous for downsizing.

The present invention solves the above problems by a simple configuration, and intends to provide a disk drive spindle motor which can be manufactured at low cost and can be easily miniaturized and thinned by reducing the processing cost. It is a thing.

[0006]

[Means for Solving the Problems]

 In this invention, a bearing holder mounting hole having a stepped portion is provided substantially at the center of a stator base made of a magnetic metal plate, and a bearing holder having a collar in the bearing holder mounting hole is locked to the stepped portion. Thus, it is preferable that the brim does not protrude above the step above the step.

[0007]

[Action]

 The stator base made of a magnetic metal plate can be simply pressed, not drawn, and the length of the bearing holder can be changed even when the height of the motor needs to be changed, so it is highly versatile. Moreover, since a large amount of magnetic flux passes through the position detecting element due to the magnetic metal plate, a smaller position detecting element can be used.

[0008] If the collar is designed so as not to protrude from the upper surface (mounting surface), the collar portion does not get in the way, and deterioration of axial straightness due to lifting or the like can be prevented.

[0009]

【Example】

 The structure of an embodiment of the present invention will be described below with reference to FIG. 1. The stator base 12 is made by pressing a magnetic metal plate such as an electrogalvanized steel plate, and a step portion 13 is provided at the center by crushing. At the same time, a bearing holder mounting hole 14 is formed. The bearing holder 20 is formed by cutting a free-cutting brass rod. The bearing holder 20 has a collar 21, a fitting portion 22 following the collar 21, and a mounting receiving portion 23 for the stator core 6, which is located above the collar 21. Has a rising portion 24 which serves as a guide when attached to a support plate (not shown).

It is desirable that the brim 21 is formed to be slightly thinner than the depth of the step portion 13 of the stator base 12. This is so that when the motor main body is mounted on the support plate using the rising portion 24 as a guide, the motor main body can be mounted without tilting.

The bearing holder 20 is fitted into the bearing holder mounting hole 14 from above so that the brim 21 locks the step portion 13 and the fitting portion 22 is swaged to widen the corner. It is attached to the stator holder 12.

Since other components are the same as those in the conventional FIG. 2, the same reference numerals are given and the description thereof will be omitted.

Although not shown, as a means for integrating the bearing holder 20 and the stator base 12, an ultraviolet curable anaerobic adhesive can be used instead of caulking. In this case, if the thickness of the collar 21 is set to be smaller than the depth of the stepped portion 13, the adhesive will be rolled in during this period, which is convenient.

[0014]

[Effect of device]

 Since the present invention is configured as described above, the stator base made of a magnetic metal plate can be formed by simple press working that does not require drawing work, and post processing such as cutting is unnecessary, which is advantageous in terms of cost and Motors of various heights can be accommodated by simply changing the cutting dimensions of the bearing holder, which enables diversification.

Moreover, since the stator base 12 is a magnetic body, a large amount of magnetic flux can be picked up by the Hall element as a position detecting element, and a smaller one can be used, so that the motor can be downsized. In addition, the magnetic leakage and the generation of electrical noise, which have been problems in the past, can be suppressed. Although the above has shown the cored type DC brushless spindle motor, it goes without saying that it can be applied to a general commutator motor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a cored type DC brushless spindle motor for driving a disk according to the present invention.

FIG. 2 is a sectional view of a main part of a conventional cored type DC brushless motor for driving a disk.

[Explanation of symbols]

 12 stator base 13 step 14 bearing holder mounting hole 20 bearing holder 21 collar 22 fitting part

Claims (2)

[Scope of utility model registration request] 1. A disk drive spindle motor comprising a stator base and a bearing holder integrated with the stator base, which is made of a magnetic metal plate, and is provided with a bearing holder mounting hole having a stepped portion substantially at the center thereof. A spindle motor for driving a disk, in which a bearing holder having the above is attached so that the brim is locked to the step portion. 2. The spindle motor for driving a disk according to claim 1, wherein the brim does not protrude from the stepped portion to the upper surface (mounting surface).