JPH0622526A - Spindle motor - Google Patents

Abstract

PURPOSE:To improve torque and make thin a spindle motor, in the spindle motor which has an iron core in a stator part, where a coil is wound, and a rotor magnet in the rotor part being held in the position opposed to the iron core. CONSTITUTION:The number of windings of a coil can be made larger by forming the space between the coil winding part 52C of an iron core 52 and a rotor 48 so as to be larger than the space between the opposite part 52A of the iron core 52 and a rotor magnet 51, and also the area of opposition between the iron core 52 and the rotor magnet 51 can be enlarged by opposing the opposite part 52A of the iron core 52 and the rotor magnet 51 to each other. Accordingly, the torque of a spindle motor 40 can be improved. Moreover, the spindle motor 40 can be thinned by the amount of the thickness of a stator board 42 by arranging the coil wound part 52C of the iron core 52 in the arranging hole 42A of the stator board 42.

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 is particularly suitable for being applied to a thin spindle motor.

[0002]

2. Description of the Related Art Conventionally, for example, a spindle motor configured to rotationally drive a disk-shaped magnetic recording medium (floppy disk) has a structure as shown in FIG.

That is, in FIG. 4, reference numeral 1 denotes a spindle motor as a whole, and a cylindrical bearing housing 3 is fixed to a through hole formed in a central portion of a plane of a stator substrate 2, and an outer peripheral portion of the bearing housing 3 is fixed. An iron core 12 formed by stacking magnetic plates is fixed. This iron core 12
A drive winding is wound around the coil to form a coil 13.

A rotary shaft 6 is rotatably supported on the inner peripheral portion of the bearing housing 3 via a slide bearing 5 and a ball bearing 4 made of, for example, a sintered oil-impregnated alloy. A rotor yoke 8 is fixed to the rotary shaft 6 via an engaging member 7 so as to rotate integrally with the rotary shaft 6. An annular rotor magnet 11 is fixed to the inner peripheral portion of the bent portion 8A at the peripheral end portion of the rotor yoke 8 at a position facing the peripheral side surface of the iron core 12.

Accordingly, by supplying a drive current to the coil 13, the rotor portion including the rotary shaft 6, the engaging member 7, the rotor yoke 8 and the rotor magnet 11 can be rotationally driven.

[0006]

By the way, in the spindle motor 1 of this type, the rotor core 11 is opposed to the peripheral side surface of the iron core 12, so that the iron core 12 and the rotor magnet 11 are arranged. The facing area becomes smaller. Therefore, in order to improve the torque of the spindle motor 1, it is necessary to increase the number of turns of the coil 13 wound around the iron core 12.

However, when the number of windings of the coil 13 wound around the iron core 12 is increased, the iron core 12 and the rotor yoke 8 are divided by this amount.
There is a problem that the winding space between them must be increased, and the thickness dimension of the spindle motor 1 is increased.

FIG. 5 shows a face-to-face flat type spindle motor, in which a rotary shaft 6 is mounted on an inner peripheral portion of a bearing housing 23 fixed to a plane center portion of a stator substrate 22 via a ball bearing 4 and a slide bearing 5. It is rotatably supported. A rotor yoke 28 is fixed to the tip of the rotary shaft 6 via an engaging member 7 so as to rotate integrally with the rotary shaft.

A flat rotor magnet 31 is fixed to the lower surface of the outer peripheral portion of the rotor yoke 28. A plurality of coils 33 are arranged concentrically on the stator substrate 22, and the coils 33 are arranged in the rotor magnet 31.
Are facing each other.

In such a flat type spindle motor, it is necessary to increase the number of turns of the coil 33 in order to improve the torque. However, in this case, the thickness of the coil 33 becomes thicker, so that the spindle motor 20 is There is a problem that it is difficult to make the device thin enough.

Further, in the conventional spindle motor 1, the bearing housing 3 for holding the bearings 4 and 5 is formed separately from the iron core 12, and is fixed to the central portion of the iron core 12. However, since the number of parts is large, the structure is complicated and the assembly process is complicated.

The present invention has been made in consideration of the above points, and an object of the present invention is to realize a spindle motor which can improve the torque and can be thinned with a much simpler structure.

[0013]

In order to solve such a problem, according to the present invention, an iron core 52 of a stator portion around which a coil 53 is wound, and a rotor magnet of a rotor portion held at a position facing the iron core 52. In the spindle motor 40 having the net 51, the step 52B is formed between the coil winding portion 52C for winding the iron core coil 53 and the facing portion 52A of the iron core 52 facing the rotor magnet 51.
The gap between the coil winding portion 52C and the rotor 48 is made wider than the gap between the rotor magnet 51 and the facing portion 52A of the iron core 52.

Further, in the present invention, an arrangement hole 42A is formed in a part of the stator substrate 42 for fixing the iron core 52, and the facing portion 52A of the iron core 52 is fixed to the peripheral end portion of the arrangement hole 42A. The coil winding portion 52C of the iron core 52 is arranged inside the arrangement hole 42A.

Further, in the present invention, the facing portion 52A of the iron core 52 is made to face the rotor magnet 51 in a plane perpendicular to the rotating shaft 6.

In the present invention, the iron core 52 of the stator portion around which the coil 53 is wound, the rotary shaft 6 rotatably supported by the central portion of the iron core 52, and the rotor fixed to the rotary shaft 6. In the spindle motor 40 having the portions 7, 48 and 51, the bearing holding portion 52D that pivotally supports the rotating shaft 6 is integrally formed with the iron core 52 at the center of the iron core 52.

[0017]

Operation: The coil winding portion 52C of the iron core 52 and the rotor portion 4
By widening the gap between the coils 8, the number of turns of the coil 53 can be increased, and the torque can be improved accordingly.
Further, an arrangement hole 42A is formed in a part of the stator substrate 42,
By disposing the coil winding portion 52C of the iron core 52 in the arrangement hole 42A, the spindle motor 40 can be thinned by the thickness of the stator substrate 42.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 4 are designated by the same reference numerals, the spindle motor 40 has a disposition hole 42A formed in a stator substrate 42 made of a non-magnetic material such as aluminum. An iron core 52 made of a magnetic material is fixed on the stator substrate 42 along the peripheral edge of the. The iron core 52 has the coil winding portion 5 radially from the center.
2C and the facing portion 52A facing the rotor magnet 5 are formed, and the facing portion 5 fixed to the stator substrate 42.
2A and a coil winding portion 52C having a step difference with respect to the facing portion 52A by a predetermined height via a bent portion 52B. The drive winding is wound around the coil winding portion 52C to form the coil 53.

A cylindrical bearing housing 52D is integrally formed at the center of the iron core 52, and a rotary shaft 6 is rotated at an inner peripheral portion of the bearing housing 52D via a ball bearing 4 and a slide bearing 5. It is freely pivoted.

A rotor yoke 48 made of a magnetic material is fixed to the tip of the rotary shaft 6 via an engaging member 7 so as to rotate integrally with the rotary shaft 6. This rotor yoke 4
A flat rotor magnet 51 is fixedly attached to the lower surface of the outer peripheral portion of 8. This rotor magnet 51 has an iron core 52
To face the facing portion 52A.

In the above structure, the spindle motor 4
0 is a coil winding portion 5 around which the coil 53 of the iron core 52 is wound.
Since 2C is formed lower than the facing portion 52A by the bent portion 52B by a predetermined height, the winding space between the coil winding portion 52C and the rotor yoke 48 can be widened. Therefore, the number of turns of the coil 53 can be increased accordingly. Further, the facing portion 52A of the iron core 52
Since the rotor magnets 51 face each other, the facing area becomes larger than in the conventional case (FIG. 4). Thus, the torque of the spindle motor 40 can be improved.

By disposing the disposition hole 42A in the substrate 42 and disposing the coil winding portion 52C and the coil 53 of the iron core 52 in the disposition hole 42A, the spindle motor 40 can be thinned by the thickness of the substrate 42. Can be converted.

According to the above construction, the bent portion 5 is formed on the iron core 52.
By forming 2B to increase the winding space of the coil winding portion 52C and disposing the coil 53 in the disposition hole 42A of the stator substrate 42A, it is possible to obtain a spindle motor 40 having a much higher torque and a thinner profile. .

Incidentally, since the bearing housing 52D for holding the bearing in the center of the iron core 52 is formed integrally with the iron core 52, the number of parts can be reduced and the construction can be simplified and the assembling process can be further simplified. Can be converted.

In the above embodiment, the coil 53 is used.
However, the present invention is not limited to this, and the coil may not be projected from the lower surface of the stator substrate 42.

That is, as shown in FIG. 2, the number of turns of the coil 73 wound around the coil winding portion 72C of the iron core 72 may be set so as not to project from the lower side surface of the stator substrate 42. In this case, Also, since the rotor magnet 51 faces the outer peripheral portion 72A of the iron core 72, the torque can be improved within a practically sufficient range.

Further, in the above-mentioned embodiment, the case where the ball bearing 4 and the slide bearing 5 are used together as the bearing has been described, but the present invention is not limited to this, and for example, as shown in FIG. Ball bearing 4A
Alternatively, the rotary shaft 6 may be pivotally supported by 4 and 4B. By doing so, the rotational load of the bearing can be further reduced as compared with the case where the plain bearing 5 is used.

[0029]

As described above, according to the present invention, the gap between the coil winding portion of the iron core and the rotor portion is made larger than the gap between the facing portion of the iron core and the rotor magnet. The number of turns can be increased, and the facing area of the iron core and the rotor magnet can be increased by making the facing portion of the iron core and the rotor magnet face-to-face.
Therefore, the torque of the spindle motor can be improved. Further, by arranging the coil winding portion of the iron core in the arrangement hole of the stator substrate, it is possible to realize a spindle motor that can be thinned by the thickness of the stator substrate.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a spindle motor according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment.

FIG. 3 is a sectional view showing another embodiment.

FIG. 4 is a cross-sectional view showing a conventional example.

FIG. 5 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

1, 20, 40, 60, 80 ... Spindle motor,
2, 22, 42 ... Substrate, 12, 52, 72 ... Iron core,
8, 28, 48 ... Rotor yoke, 11, 31, 51 ...
… Rotamagnet.

Claims (4)

[Claims] 1. A spindle motor having an iron core of a stator part around which a coil is wound, and a rotor magnet of a rotor part held at a position facing the iron core, wherein the coil of the iron core is wound. A step is formed between the coil winding part and the facing part of the iron core facing the rotor magnet, and the gap between the coil winding part of the iron core and the rotor is set to the rotor magnet and the iron core. The spindle motor is characterized in that it is formed wider than the gap between the facing portions of the. 2. An arrangement hole is formed in a part of a stator substrate for fixing the iron core, the facing portion of the iron core is fixed to a peripheral end portion of the arrangement hole, and the coil winding of the iron core. The spindle motor according to claim 1, wherein the turning portion is arranged inside the arrangement hole. 3. The spindle motor according to claim 1, wherein the facing portion of the iron core faces the rotor magnet in a plane perpendicular to a rotation axis. 4. A spindle motor having an iron core of a stator part around which a coil is wound, a rotary shaft rotatably supported by the center of the iron core, and a rotor part fixed to the rotary shaft. A spindle motor, characterized in that a bearing holding portion for pivotally supporting a rotating shaft is formed integrally with the iron core at the center of the iron core.