JP2002325411A - Spindle motor with disk-mounting section and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a turntable function in which a surface shake is reduced, using a simple constitution by devising a rotor case, and to manufacture a spindle motor having an automatic balance correction function, while being low in attitude. SOLUTION: The spindle motor with a disk placing section is composed of the rotor case (1) in which an axial support section (1a) is installed at a center, while a plurality of disk placing guide sections (1b) are arranged on the top face of the periphery of the axial support section at regular intervals and a disk-mounting surface (1c) is formed, a shaft (2) in which the axial supporting section is clearance-fitted to the shaft and which is fixed by means excepting a press-in, magnets (4) arranged inside the rotor case, armature stators (5) made to face the magnets via air gaps, and a stator base (7), in which the armature stators (5) are disposed while the shaft is supported inside the armature stators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an MD, a CD, and a DVD.
TECHNICAL FIELD The present invention relates to a spindle motor having a disk mounting portion capable of mounting a disk by a rotor itself without specially preparing a turntable.

[0002]

2. Description of the Related Art A spindle motor for driving these optical media is generally provided with a turntable on which an optical media is mounted on an output shaft extending from a motor body, that is, the motor and the turntable are separately provided. It has become. The permissible runout of the turntable of such a motor has become as strict as possible with an increase in the recording density of a disk medium. In recent years, spindle motors equipped with an auto balancer that automatically corrects these imbalances below a turntable in order to prevent vibration due to imbalance of a rotating system including a medium of a high-speed rotation motor have come to be known. .

[0003]

Although there are various types of this auto balancer, recently, as shown in FIG. 5, a turntable T and a shallow cylinder arranged below the turntable are arranged on the output shaft of a motor section M as shown in FIG. In some cases, a plurality of small balls B are stored in a case E, and the centrifugal force imbalance during rotation is corrected by utilizing the free movement of the balls B. In such a device, since there is a turntable and an unbalance correction member, there is a problem in that a demand for a low attitude tends to cause wrinkles on the motor side and sacrifices the characteristics of the motor. To maintain this characteristic, expensive magnets and the like must be used. In addition, since the configuration supporting the bottom of the stator base SB is often used, the height to the turntable greatly affects the shaft deflection. In other words, the accuracy of each member is pursued more than necessary,
There are problems such as runout when the turntable is mounted and variations in the thickness of the friction sheet. In addition, the cost of the turntable and the unbalance correction member occupy a large amount, resulting in an expensive motor.

A first object of the present invention is to reduce the number of members by devising a rotor case so as to exhibit a turntable function with reduced surface runout with a simple structure. A second object of the present invention is to enable the disk mounting portion to be leveled out with a simple configuration. A third object of the present invention is to provide a low-profile device having an automatic balance correction function.

[0005]

According to a first aspect of the present invention, a shaft support is provided at the center and a disk mounting guide is provided on the upper surface around the shaft support. A rotor case having a disk mounting surface,
A shaft fixed to the shaft support by a means other than press-fitting, a magnet disposed inside the rotor case, an armature stator desired by the magnet through a gap, and an electric motor. The armature stator is provided, and the armature stator includes a stator base supporting the shaft inside. As a more specific means for solving the problem, as in the inventions described in claims 2 and 3, as a means other than the press-fitting, the tip of the shaft and the shaft support are laser-welded, or the shaft and the shaft support are filled with an anaerobic adhesive. Can be achieved. As another specific means for solving the problem, as in the invention as set forth in claim 4, a plurality of the disk mounting guides are raised with a predetermined gap, and at least one disk chuck spring is formed from this gap. This can be achieved with a slightly protruding arrangement. Another specific means for solving the problem may be one in which a disk slip is disposed on the disk mounting surface as in the invention as set forth in claim 5. According to another aspect of the present invention, a bulging portion is formed over the entire circumference so that the outer peripheral portion of the rotor case rises, and a balance correction is formed inside the bulging portion. This can be achieved by arranging a plurality of balls as members. The problem solving means for manufacturing such a motor is described in claim 7,
After the disk mounting surface is leveled using a jig as in the invention shown in FIG. 8, the tip of the shaft and the shaft support of the rotor case are fixed by laser welding, or the disk mounting surface is leveled using a jig. After that, it can be achieved by fixing the shaft and the shaft support of the rotor case with an anaerobic adhesive. And
In the case where an anaerobic adhesive is used, the flattening jig of the media mounting portion of the turntable is a media disk type in which the runout is corrected by utilizing inertia during rotation. This can also be achieved by the following manufacturing method.

According to the means for achieving the object set forth in the first aspect, a turntable function capable of correcting the horizontality by the rotor itself can be constituted. According to the second and third aspects of the invention, it is possible to correct the level of the disk mounting surface. Claim 4
According to the means for achieving the above object, the media disk can be temporarily held. According to the means for achieving the object, a slip of the high-speed rotating media disk can be prevented. According to the means for achieving the object, the imbalance of the rotating system can be automatically corrected. According to the means for achieving the object, the horizontality of the disk mounting surface can be easily obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below based on embodiments shown in the drawings. FIG. 1 shows a first embodiment of the present invention, and shows a longitudinal section of a cored type spindle motor provided with a disk mounting portion.
FIG. 3 is a vertical sectional view taken along line AA of FIG. FIG. 2 is a plan view of the rotor portion of FIG. FIG. 3 is an enlarged view of a modification of the main part of FIG. FIG. 4 shows the second embodiment and is a longitudinal sectional view of an axial gap type spindle motor.

In FIGS. 1 and 2, reference numeral 1 denotes a rotor case having a disk mounting function which is a feature of the present invention.
It is fitted with the following gaps and held by welding Y. A plurality (five in this example) of disc mounting guides 1b are protruded from the peripheral upper surface with an appropriate gap provided integrally. The disk mounting guide 1b has a slightly smaller radius of curvature so as to be concentric with the shaft according to the inner diameter of the disk to be mounted and so as not to damage the disk. The rotor case 1 is formed with a bulging portion 1c so that the outer peripheral portion is further raised. 3, the at least one (five in this example) disk chuck portion 3 a is protruded slightly from the plurality of disk mounting guides into the rotor case so that the disk can be mounted without play. This is a disk chuck spring arranged. The flat portion 3b of the disc chuck spring 3 is formed so as to cover a hole 1d which must be formed when the disc mounting guide 1b is protruded, and a preferred position is determined by the positioning guide 1e. The disk chuck portion 3 with respect to the shaft 2
a of the rotor case 1 by a manufacturing method including
It is spotted at a position without d. Therefore, it is desirable that the positioning guide 1e and the disc chuck spring 3 are set to be slightly loosely fitted. By doing so, the disk chuck spring 3 can be automatically centered by making a predetermined effort to obtain a predetermined spring property. The upper surface of the bulging portion 1c serves as a disk mounting surface, and a non-slip sheet ST is attached so that the disk does not slip at high speed. Here, the shaft 2 and the shaft supporting portion 1a are not fixed by press-fitting, but by means of a shaft in order to obtain the horizontality (perpendicularity with the shaft) of the surface of the non-slip means (here, the sheet ST) based on the shaft. Using the motor mounting jig J1 and the leveling jig J2 within the range of the gap with the shaft support portion, using a gauge (not shown) or the like to correct the disk mounting surface runout and maintaining the state. This is based on a manufacturing method of laser welding Y between the shaft tip 2a and the shaft support 1a. Here, J3 is a jig made of a magnetic material, and has a function of maintaining the level of the leveling jig J2 by urging the leveling jig J2 toward the motor side by the magnetic force of the magnet for attracting media. As a means other than press-fitting the shaft and the shaft supporting portion, the gap between the shaft 2 and the shaft supporting portion 1a may be filled with an anaerobic adhesive N as shown in FIG. Here, horizontal jig J2
By adding the weight of the outer peripheral portion to the media disk size and imparting inertia, the anaerobic adhesive can be fixed using the hardening time of the anaerobic adhesive while leveling using centrifugal force during rotation. In this manner, the horizontal centering jig J2 can be used for automatic centering using the curing time, and the cost can be reduced without considering the turntable separately. In addition, since the anaerobic adhesive can be peeled off by heating, it is convenient from the top of the maintenance, and the curing time can be shortened by using an anaerobic adhesive of an ultraviolet curing type. Inside the rotor case 1 thus constructed, a rubber or other plastic magnet 4 is stored in a cylindrical shape constituting a radial gap type, and furthermore, on the upper surface of the magnet 4 via a thin magnetic shielding plate 4a. A plurality of balls B as unbalance correcting means are rotatably stored in a space inside the bulging portion 1c. In the figure, 1f is a ball stopper formed by deforming the rotor case all around so that the ball B does not come off, and K is a magnet as a magnetic material for adsorption. If the ball is non-magnetic, the thin magnetic shielding plate 4a is unnecessary.

The rotor R1 constructed as described above is combined with the radial gap type armature stator S1 to form a brushless motor. The stator S1 has a core 5 formed by laminating a plurality of silicon steel plates and a salient pole portion 5a of the core.
Armature coil 6 wound around the blade portion 5
b faces the cylindrical magnet 4 via a gap, and is fixed via a brass bearing housing 8 integrated with a stator base 7 made of an iron circuit board. As the fixing means, welding or adhesion can be adopted. The stator S thus configured
1, the rotor R1 is rotatably mounted on the bearing housing 8 via the shaft 2 via the oil-impregnated bearing 8b to complete a radial gap type brushless spindle motor. Here, since the center of the magnet and the core is deliberately shifted and the rotor R1 is constantly attracted to the stator S1, there is no possibility that the rotor will come off. Further, in order to secure the axial pull-out strength of the rotor, a groove may be formed in the shaft as shown here and the rotor may be forcibly inserted into the stopper ring 8a. .

FIG. 4 shows an axial gap type brushless spindle motor according to a second embodiment of the present invention. That is, the upper surface of the rotor case 11 is the same as that of FIG. Due to the mold, a plurality of disk-shaped ring-shaped magnets 44, which are alternately magnetized by NS, are fixed to the ceiling, and the outer periphery is designed to shield the magnetism to some extent so that the leakage magnetic field of the magnet 44 is used intentionally. The steel ball B is stored as a balance correction member via a ball holder Ba made of a thin magnetic plate. The stator S2 for driving such a rotor R2 is composed of a plurality of air-core armature coils 66 mounted on a stator base 77 made of a magnetic material so as to face the magnet 44 via an axial gap. .
Here, since the axial gap type is slotless, the rotor R
2 is strongly attracted to the stator base 77, so that a brake loss in the axial direction becomes a problem. In this case, a V-shaped gouge is used, and one bearing ball BB is stored therein. With this configuration, the bearing ball BB rotates in response to the rotation of the shaft and revolves around the V-shaped groove, so that the brake loss is reduced. In this example, a thin ring-shaped disk 9 is spotted on the outer peripheral portion of the rotor case 11 assuming that the motor body is too small with respect to the disk. Since this thin ring-shaped disk 9 can be formed by press working, there is no great cost penalty. Of course, this ring-shaped disk 9 can also be applied to the above-mentioned radial type motor. In each embodiment, the ball B as the balance correction member may be made weakly magnetic (such as stainless steel) or non-magnetic so as not to be greatly affected by the magnetic field of the magnets 4 and 44. In the drawings, the same members as those in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted. Although the jig is not shown here, the ring-shaped disk 9 can be leveled out in the same manner as described above.

Note that the friction sheet ST
Instead of this, a resin having a slip-preventive function may be applied while being rotated while being rotated. Also in this case, the variation in the thickness of the dropped resin can be corrected by manufacturing as described above.

Further, the present invention can be embodied in various other forms without departing from the technical idea or characteristics thereof. Therefore, the above-described embodiment is merely an example and should not be construed as limiting. The technical scope of the present invention is defined by the appended claims, and is not limited by the description.

[0013]

According to the first aspect of the present invention, the spindle motor having the disk mounting portion according to the present invention can constitute a turntable function capable of correcting the horizontality by the rotor case itself. Since there is no need to provide a special turntable, the cost can be reduced and the attitude of the motor itself can be reduced. As a result, the thickness of the motor can be increased by the amount of the conventional turntable, so that an inexpensive magnet with the same characteristics can be used. According to the above specific inventions, the following effects can be exerted. According to the second and third aspects of the present invention, it is possible to easily correct the horizontality of the disk mounting surface, and to obtain a spindle motor with less runout. According to the present invention, the media disk can be held with good centering. According to the fifth aspect of the invention, slipping of the high-speed rotating media disk can be prevented. According to the invention described in claim 6, the imbalance of the rotating system can be automatically corrected. According to the seventh, eighth, and ninth aspects of the present invention, it is possible to easily obtain the levelness of the disk mounting surface and to obtain a disk having a turntable function with extremely little runout.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention and shows a longitudinal section of a cored type spindle motor having a disk mounting portion, and its cutting position is a sectional view taken along line AA of FIG. is there.

FIG. 2 is a plan view of a rotor part of FIG. 1;

FIG. 3 is an enlarged sectional view of a main part of a modification of FIG. 1;

FIG. 4 is a longitudinal sectional view of an axial gap type spindle motor according to the second embodiment.

FIG. 5 is a cross-sectional side view of a main part of the conventional motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor case 1a Shaft support part 1b Disk mounting guide 1c Swelling part 1d hole 1e Positioning guide 1f Ring-shaped ball stopper part 2 Shaft 2a Shaft tip 3 Disk chuck spring 3a Disk chuck part 3b Flat part 4,44 Magnet 4a Thin Magnetic shielding plate 5 Core 6 Armature coil 66 Air-core armature coil R1, R2 Rotor S1, S2 Stator B Plural balls Ba Ball holder K Attraction magnet ST Non-slip sheet Y Welded part N Anaerobic adhesive J1, J2, J3 Jig BB Bearing ball

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H02K 15/16 H02K 15/16 A 21/24 21/24 M 29/00 29/00 Z // F16F 15 / 32 F16F 15/32 K F term (reference) 5D109 BA03 BA06 BA12 BA14 BA17 BA20 5D138 RA05 RA08 RA11 RA15 SA13 SA20 TA02 TA07 TA08 TA12 TA17 TA23 TA33 5H019 AA06 AA09 CC02 CC04 CC09 DD01 DD06 EE01 EE08 EE14 FF01 FF01 A01 BB04 BB07 BB14 BB15 PP02 SS10 SS16 SS18 SS54 SS55 TT05 TT27 TT30 5H621 BB07 BB10 GA01 GA04 HH01 JK15 JK19

Claims (9)

[Claims] 1. A rotor case having a shaft support at the center, a disk mounting guide disposed on a peripheral upper surface thereof, and a disk mounting surface, wherein the shaft support is slightly loosely fitted to the shaft. A shaft fixed by means other than press-fitting, a magnet disposed inside the rotor case, an armature stator desired through a gap in the magnet, and an armature stator provided with the armature stator. And a stator base supporting the shaft inside the spindle motor. 2. The spindle motor according to claim 1, wherein the tip of the shaft and the shaft support are laser-welded as means other than the press-fitting. 3. The spindle motor according to claim 1, wherein the shaft and the shaft support are filled with an anaerobic adhesive as a means other than the press-fitting. 4. A plurality of the disc mounting guides are raised with a predetermined gap, and at least one
2. The spindle motor according to claim 1, wherein the disc chuck springs are arranged so as to slightly protrude. 5. The spindle motor according to claim 1, wherein a disk slip is provided on the disk mounting surface. 6. The disk mounting device according to claim 1, wherein a bulging portion is formed over the entire circumference so that an outer peripheral portion of the rotor case is raised, and a plurality of balls are arranged inside the bulging portion as a balance correction member. Spindle motor with a section. 7. A method for manufacturing a spindle motor provided with a disk mounting portion according to claim 1, wherein the disk mounting surface is leveled using a jig, and then the shaft is set. A method for manufacturing a spindle motor having a disk mounting portion, wherein a tip of the rotor and a shaft support portion of a rotor case are fixed by laser welding. 8. A method for manufacturing a spindle motor provided with a disk mounting portion according to claim 1, wherein the disk mounting surface is leveled using a jig, and then the shaft is mounted. A method of manufacturing a spindle motor having a disk mounting portion, wherein an anaerobic adhesive is used to fix the space between the rotor case and the shaft support of the rotor case. 9. The manufacturing method of a spindle motor according to claim 8, wherein the jig for leveling out the media mounting portion of the turntable is a media disk type, and the runout is corrected by using inertia during rotation.