JPH09252568A - Small size disk motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil winding part by which a sufficient magnetomotive force is generated in the stator core of a small size disk motor and, further, improve the position precision between components such as between the stator core and a rotary shaft and stabilize the performance such as the motor revolution precision by a method wherein a bearing is directly inserted into the stator core. SOLUTION: A stator core 5 is subjected to an insulation treatment and, at the same time, molded with resin 7 and a sintered metal bearing 8 is pushed into the inner circumference side of the stator core 5 with the resin layer therebetween. After a sizing treatment, a rotary shaft 9 is inserted and supported by the bearing 8 so as to rotate freely. The stator core 5 consists of a plurality of salient pole cores which protrude outward radially and exciting coils 6 are wound on the respective salient pole cores. The inner circumferential surface of a rotor 1 which faces the stator core 5 is so magnetized as to have magnetic poles (N-poles and S-poles) with a required pitch in the circumferential direction to form a rotor magnet 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses optical or magneto-optical technology to record, reproduce, or record / reproduce devices such as CDs (compact discs) and DVDs.
The present invention relates to an outer rotor type small disk motor for rotating a recording / reproducing member (disk) such as a (digital video disk).

[0002]

2. Description of the Related Art Outer rotor type disk motors are
It is a motor suitable as a drive source for a CD, a DVD, a magnetic disk device, or the like. In addition, this type of motor is generally configured as a brushless motor from the viewpoints of easy speed-up, less rotational unevenness, and low noise.

FIG. 3 is a vertical sectional view illustrating the structure of a conventional disk motor.

In FIG. 3, a rotor magnet 104 is fixed to the inside of a cup-shaped rotor case 103, and a rotor 101 composed of the rotor case 103 and the rotor magnet 104 is structured to rotate so as to surround a stator 102. .

The central portion of the rotor case 103 has a boss 108.
The rotary shaft 111 is fixed to the boss 108 by press fitting or the like, and the rotor 101 is integrated with the rotary shaft 111.

On the other hand, a stator core 105, in which a coil 106 is wound around a stator 102, is mounted on an inner diameter portion of a bearing housing 107 by bearings 109 and 110, and a rotating shaft 111 is provided.
Has a structure that rotatably supports.

The bearing housing 107 is fixed to the motor fixing base 112 by caulking the tip.

Further, a turntable 113 for mounting a disc on the upper part of the rotary shaft 111 is provided with a rotary table 111.
Has been fixed by.

[0009]

However, the conventional small-sized disk motor as described above has the following technical problems in manufacturing the stator 102.

1) As for the stator core 105, magnetic plates punched in a slot shape by a press are laminated to form the stator core 105, and the coils 106 are formed on the stator core.
After winding, the process of fixing this to the bearing housing 107, further inserting and fixing the bearings 109 and 110 from above and below, and press-fitting the rotary shaft 111 are adopted, so many complicated processes are required in manufacturing the motor. There was a technical problem that various processes were required.

2) In a small motor, the stator core 105 is attached to the rotary shaft 11 in order to maximize the coil winding portion.
Bearing housing 107 and bearing 10 at a limited interval of 1
It is necessary to insert 9, 110, as a result, the thickness of the bearing housing 107 becomes thin, and there is a problem such as eccentricity due to deformation due to press fitting.

3) Rotor 101 and turntable 113
Since they are separated and fixed to the rotary shaft 111 by press fitting or the like, there are many assembling steps and it is difficult to adjust the position accuracy. Further, since the turntable 113 is made of metal such as brass and iron, there is a problem that material cost and processing cost are increased.

An object of the present invention is to provide a coil winding portion capable of generating a sufficient magnetomotive force on a stator core in a small-sized disk motor, and further improve the positional accuracy between the stator core and components such as a rotary shaft to improve motor rotation accuracy. It is an object of the present invention to provide a disk motor capable of stabilizing performances such as the above, and further reducing the number of parts to improve the assembling property and the material cost of component parts.

[0014]

In order to achieve the above object, the present invention provides a bearing housing for mounting a bearing of a rotating shaft, a stator core around which a coil is wound, and a rotating shaft. A fixed rotor case and a cylindrical rotor magnet that is attached to the rotor case so as to face the stator core, and is further fixed to the upper part of the rotating shaft.
In a small disc motor with a turntable for mounting the disc, the bearing inserts directly into the stator core.

Further, the stator core is molded with an insulating resin, and the bearing is inserted through the molding resin.

Further, the turntable is made of resin, the turntable is welded and integrated with the rotor case, and the rotary shaft is fixed to the turntable portion by press fitting or the like.

A sintered metal or ball bearing is used as the bearing.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a small disk motor to which the present invention is applied will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing an embodiment of a disk motor according to the present invention. In FIG. 1, a rotor 1 has a rotor magnet 4 fixed to the inside of a cup-shaped rotor case 3 made of zinc-plated soft iron, and is composed of the rotor case 3 and the rotor magnet 4. on the other hand,
The stator 2 is a stator core 5 made of a laminated body of silicon steel plates.
The coil 6 is wound around the rotor 1, and the rotor 1 is configured to rotate around the rotating shaft 9 so as to surround the stator 2.
As the rotor magnet 4, a neodymium-iron-boron-based magnet, which is small in size and can obtain high torque, is suitable.

Here, the stator core 5 is molded with the resin 7 at the same time as the insulating treatment, and the sintered metal bearing 8 is attached to the inner diameter of the stator core 5 through the resin layer 7'by press fitting or the like. The sintered metal is impregnated with a lubricant. After the sizing process, the rotary shaft 9 is inserted. In this way, the rotating shaft 9 is rotatably supported by the bearing 8.

At least one end of the molding resin 7 is fixed to the motor fixing base 10 by welding or the like. Polycarbonate or the like is used for the mold resin 7.

The stator core portion 5 is composed of a plurality of salient pole type cores that radially protrude outward in the radial direction, and an exciting coil 6 is wound around each stator core portion 8.

The inner peripheral surface of the rotor 1 facing the stator core portion 8 has magnetic poles (N pole and S pole) at a predetermined pitch in the circumferential direction.
The poles are magnetized to form the rotor magnet 4.

With such a structure, the bearing 8 can be directly inserted into the stator core 5 without separately providing a bearing holder.

As a result, the bearing housing can be omitted, the number of parts can be reduced, and the assembly process can be simplified. Moreover, since the coil winding portion of the stator core can be widened by eliminating the bearing housing, the number of windings can be increased and the coil diameter can be increased, so that the magnetomotive force can be increased.

Alternatively, the insulating mold resin 7 may be formed only on the coil winding portion of the stator core 5, and the bearing 8 may be directly fixed to the inner diameter of the stator core 5 by press fitting or the like.

On the other hand, the rotor 1 is welded and integrally formed at an end 12 of a turntable 11 molded with resin. A protrusion 13 is provided on the upper surface, a disc is mounted on the protrusion 13, and a rubber sheet 14 is adhered to the outer peripheral surface so as not to damage the disc. Furthermore, a magnet 15 for clamping is arranged inside the protrusion,
The structure is such that the mounted disk is attracted and fixed to a separately provided fixing plate.

In this way, by integrating the parts in which the turntable 11 and the rotor 1 are conventionally separated,
The boss holding the rotor can be omitted. Further, since the turntable 11 is a resin molded product, it has the advantages of being lighter in weight and smaller in load than metal, and the manufacturing cost can be significantly reduced.

Further, the positional accuracy between the stator 2 and the components such as the rotary shaft 9 can be increased to stabilize the motor rotational accuracy.

FIG. 2 is a vertical sectional view showing another embodiment of the small disk motor according to the present invention.

In FIG. 2, the rotor 1 has a rotor magnet 4 fixed to the inside of a cup-shaped rotor case 3 and is composed of the rotor case 3 and the rotor magnet 4. On the other hand, in the stator 2, a coil 6 is wound around a stator core 5. The rotating shaft 9 is fixed to the center of the rotor 1 by press fitting or the like.

Here, at the same time as the stator core 5 is insulated, it is molded with resin 7, and two ball bearing bearings 8a and 8b are formed inside the stator core 5 with a resin layer 7'in between.
Is installed by press fitting. Then, the rotary shaft 9 is press-fitted. In this way, the rotating shaft 9 is rotatably supported by the bearings 8a and 8b.

As another method, the insulating mold resin 7 may be formed only on the coil winding portion of the stator core 5, and the bearing 8 may be directly fixed to the inner diameter of the stator core 5 by press fitting or the like.

The ball bearing bearings 8a and 8b are constructed so as to apply a preload to the inner ring. That is, the bearing 8a is preloaded by the end 12 of the turntable 11, and the other bearing 8b is preloaded by the disc spring 16. The preload means is not particularly limited, and depending on the case, a spiral spring may be disposed inside to preload vertically.

In addition, the constituent materials and structures of the rotor 1, the stator 2 and the turntable 11 are almost the same as those of the embodiment shown in FIG.

As described above, even if the bearing is a ball bearing, the effects of the present invention described in the embodiment of FIG. 1 can be obtained similarly.

[0037]

According to the present invention, the bearing housing for mounting the bearing of the rotary shaft, the stator core around which the coil is wound, the rotor case fixed so as to rotate integrally with the rotary shaft, and the stator core are opposed to each other. And a cylindrical rotor magnet attached to the rotor case, and a small disc motor further provided with a turntable for mounting a disc, which is fixed to the upper part of the rotating shaft, in which the bearing is directly inserted into the stator core, Alternatively, since the stator core is molded with the insulating resin and the bearing is inserted through the molding resin, it is not necessary to separately provide the bearing housing, so that the number of parts can be reduced and the assemblability and the cost can be reduced.

Further, since the turntable is made of resin, the turntable is welded and integrated with the rotor case, and the rotary shaft is fixed to the turntable portion by press fitting or the like, the rotor is fixed to the rotary shaft. Since the boss for fixing is not provided, the number of parts can be reduced and the assemblability can be improved.

Further, as a result of the integrated structure, the assembly and adjustment are easy, the positional accuracy between the constituent parts can be improved, and the performance such as the motor rotation accuracy can be stabilized, and the material cost and processing of the constituent parts can be achieved. Provided is a small-sized disk motor that can reduce costs.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a small disc motor according to the present invention.

FIG. 2 is a longitudinal sectional view showing another embodiment of the small disc motor according to the present invention.

FIG. 3 is a vertical cross-sectional view showing the structure of a conventional small disc motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Rotor, 2 ... Stator, 3 ... Rotor case, 4 ... Rotor magnet, 5 ... Stator core, 6 ... Coil, 7 ... Mold resin, 8 ... Bearing, 9 ... Rotating shaft, 10 ... Motor fixing base, 11 ... Turntable , 14 ... Rubber sheet 15 ... Clamp magnet.

Claims (5)

[Claims] 1. A bearing housing for mounting a bearing of a rotary shaft, a stator core around which a coil is wound, a rotor case fixed so as to rotate integrally with the rotary shaft, and the rotor facing the stator core. A small disc motor comprising a cylindrical rotor magnet attached to a case and a turntable fixed to an upper portion of the rotary shaft for mounting a disc, wherein the bearing is directly inserted into the stator core. Characteristic small disc motor. 2. The small disk motor according to claim 1, wherein the stator core is molded with an insulating resin, and the bearing is inserted through the molding resin. 3. The turntable is formed of resin, the turntable is welded and integrated with the rotor case, and the rotary shaft is fixed to the turntable portion by press fitting. The described small disc motor. 4. The small disc motor according to claim 1, 2 or 3, wherein the bearing is made of sintered metal. 5. The small disc motor according to claim 1, 2 or 3, wherein the bearing comprises a ball bearing.