JPH09215231A - Spindle motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a motor in which a spacer is eliminated and whose component costs and production costs are suppressed. SOLUTION: A motor is constituted of a stator core 1 on which a coil 15 is wound, of a driving magnet 2 which is arranged so as to face the stator core 1, of a rotor 3 which is turned integrally with the driving magnet 2, of a bearing means 4 which supports the rotor 3 so as to be freely rotatable and of a board 5 which holds the stator core 1. The stator core 1 is composed of a plurality of core plates 1a provided with salient poles and of an auxiliary core plate 1b which is installed so as to be sandwiched between the core plates 1a and the board 5. The core plates 1a and the auxiliary core plate 1b are laminated and caulked integrally, and a gap is formed between the salient poles and the board 5.

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, more particularly, to the structure of a stator core.

[0002]

2. Description of the Related Art A spindle motor is used, for example, as a motor for mounting a magnetic recording medium such as a floppy disk and for rotationally driving it, and as a motor for various other purposes. An example of a conventional spindle motor is shown in FIG. In FIG. 5, the substrate 45 has a hole, and the lower portion of the bearing holder 42 is fitted into this hole. A flange 42a is formed on the outer circumference of the bearing holder 42, and a portion below the flange 42a is inserted into the hole of the substrate 45. Further, a cylindrical portion 42b is provided above the flange 42a of the bearing holder 42,
On the inner peripheral surface of the cylindrical portion 42b, the ball bearing 3 is provided as bearing means.
The outer ring 4 is fitted and fixed.

A spacer 50 is provided on the substrate 45 and around the flange 42a of the bearing holder 42. Further, the stator core 31 is provided on the spacer 50. The stator core 31 is formed by stacking a plurality of core plates 31a made of magnetic plates, and a plurality of core plates 31a are formed on the outer periphery at equal intervals in the circumferential direction. Salient poles are formed. A coil 45 is attached to the arm of such salient pole.
Is wound. The spacer 50 of the stator core 31 formed by stacking a plurality of core plates 31a
The innermost portion of the lowermost core plate 31a disposed above extends toward the bearing holder 42, and the end of this extended portion is bent to form a bent portion 31b.
The bent portion 31b is placed on the flange 42a. Therefore, by inserting the screw 51 from the substrate 45 side, penetrating the spacer 50, and screwing it into the lowermost core plate 31a, the lowermost core plate 31a of the stator core 31 is inserted.
The bent portion 31b provided on the base plate 3 connects the flange 42a to the substrate 3
The stator including the bearing holder 42, the spacer 50, the stator core 31 and the like is pressed onto the substrate 3 to press it to the substrate 3 side.
5 will be fixed on.

The bearing holder 42 has a hole in the center thereof, and the rotary shaft 43 is inserted into this hole. The outer peripheral surface of the rotating shaft 43 is fixed to the inner ring of the ball bearing 34 attached to the bearing holder 42. Therefore, the rotating shaft 42 is rotatable by the ball bearing 34 with respect to the bearing holder 42, which is a stator, the spacer 50, the stator core 31, and the like.

Further, on the outer peripheral surface of the upper end of the rotary shaft 42,
Hub stand 3 on which various media such as floppy disks are placed
9 is attached. The hub base 39 has the rotating shaft 4 on the lower side.
2 has a protrusion so as to surround 2, and the lower end surface of this protrusion is in contact with the upper end surface of the inner ring of the ball bearing 34.
A cup-shaped rotor case 38 is attached to the outer periphery of the hub base 39 by caulking or the like. A hole 38a is formed in the ceiling portion of the rotor case 38, and the drive pin 41 projects upward from the hole 38a. The drive pin 41 is attached to a leaf spring 52 attached to the surface of the rotor case 38 on the side of the stator core 31, and the drive pin 41 is attached to the hole 38a by the leaf spring 52.
Inside, it is possible to sink downwards and return to its original position. The drive pin 41 having such a configuration engages with a drive pin insertion hole of a floppy disk (not shown) mounted on the hub base 39, and plays a role of rotationally driving the floppy disk as the hub base 39 rotates.

Further, on the upper end surface of the rotor case 39,
Moreover, on the outer peripheral side of the hub base 39 and the drive pin 41,
In order to attract the hub of a floppy disk (not shown) mounted on the hub base 39, a chucking magnet 40
Is provided.

Further, the rotor case 38 has a peripheral wall on the outer peripheral side, and the ring-shaped drive magnet 32 is attached to the inner peripheral surface of the peripheral wall. Drive magnet 32
The inner peripheral surface of is opposed to the salient poles of the stator core 31 described above with a certain gap. Therefore, the drive magnet 32 is magnetically biased in the circumferential direction by controlling the energization of the coil 45 wound around the arm of the salient pole of the stator core 31, and the rotor case 38, the drive pin 41, and the hub base 39. The rotary shaft 43 is driven to rotate. like this,
The rotor 33 is composed of the rotationally driven members such as the drive magnet 32, the rotor case 38, the drive pin 41, the hub base 39, and the rotary shaft 43.

[0008]

In the spindle motor having the above structure, the stator core 31 cannot be directly arranged on the substrate 35 because the coil 45 is wound around the arm of the salient pole. For this reason, the spacer 50 is interposed between the stator core 31 and the substrate 35 to provide a space around which the coil 45 is wound.

However, the spacer 50 is used for the stator core 3
Since it is a member different from 1, the number of parts is increased by using the spacer 50, and the number of processing steps is increased, so that the parts cost and the manufacturing cost are increased.

The present invention has been made in order to solve the above problems of the prior art, and an object of the present invention is to provide a spindle motor in which the component cost and the manufacturing cost are suppressed.

[0011]

According to the first aspect of the present invention,
A stator core around which a coil is wound, a drive magnet arranged to face the stator core, a rotor rotating integrally with the drive magnet, bearing means for rotatably supporting the rotor,
In a spindle motor including a substrate holding a stator core, the stator core includes a plurality of core plates having salient poles and an auxiliary core plate sandwiched between the core plate and the substrate. And the auxiliary core plate are integrally laminated and caulked, and a gap is formed between the salient pole and the substrate.

According to a second aspect of the present invention, the bearing means includes a thrust ball bearing having a ball and a washer to support the thrust load of the rotor, and the auxiliary core plate projects inward in the radial direction. It is characterized by including a guide portion for guiding the washer of the ball bearing in the radial direction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a spindle motor according to the present invention will be described below with reference to the drawings. In FIG. 1, the substrate 5 has a hole, and the lower end portion of the bearing holder 12 is fitted in this hole. The bearing holder 12 has a caulking portion on the lower side, and is fixed by caulking the caulking portion to the edge of the hole of the substrate 5. On the outer periphery of the bearing holder 12, a ring-shaped thrust ball bearing 4 which is a bearing means is provided on the substrate 5. Thrust ball bearing 4
Is composed of a ball and an upper washer 4a and a lower washer 4b that can be rotated relative to each other by sandwiching them between the balls, and the lower washer 4b is mounted on the substrate 5. . Therefore, the washer 4a can freely rotate in the horizontal direction with respect to the washer 4b.

The stator core 1 is mounted on the substrate 5 and on the outer circumference of the thrust ball bearing 4. As shown in FIG. 2, the stator core 1 has radial salient poles on the outer peripheral side at equal intervals. The salient poles are formed on the tip end and extend toward both sides in the circumferential direction.
And an arm portion 1e connecting the base portion of the stator core 1 with each other. Further, as shown in FIG.
The coil 15 is wound. Further, the stator core 1
Is formed by laminating a plurality of core plates made of magnetic plates, as shown in FIGS. The core plate is a core plate 1a having a plurality of salient poles as shown in FIG.
And an auxiliary core plate 1b having no salient pole as shown in FIG.
It is composed of

As shown in FIG. 4, the auxiliary core plate 1b is
Three tongues 1 that are ring-shaped and project radially inward
c, 1d, and 1e. Also, the three tongue pieces 1c,
1d and 1e are connected by an arcuate arm 1g. A tongue piece 1c and a tongue piece 1e are provided at both ends of the arm portion 1g, and the tongue piece 1c is provided between the tongue piece 1c and the tongue piece 1e of the arm portion 1g.
d is provided. Further, among the tongue pieces 1c, 1d, and 1e, the tongue piece 1c and the tongue piece 1e have the same shape.

As shown in FIG. 3, the stator core 1 is formed by laminating a plurality of core plates 1a on the upper surface of the auxiliary core plate 1b and then laminating and crimping. By stacking, the arm portion 1g of the auxiliary core plate 1b completely overlaps with the base portion of the core plate 1a. Further, the tongue pieces 1c, 1d, 1e of the auxiliary core plate 1b are configured to project radially inwardly of the core plate 1a.

By providing the auxiliary core plate 1b on the lowermost side (lowermost layer) of the stator core 1, when the stator core 1 is directly attached to the substrate 5 using a fastening member or the like, the auxiliary core plate 1b is located on the lowermost side of the stator core 1. The auxiliary core 1b can serve as a spacer. That is, a gap necessary for winding the coil 15 between the salient poles and the substrate 5 is formed, and the portion of the core plate 1a laminated by the auxiliary core 1b is lifted. The relationship between the thickness of the auxiliary core plate 1b and the winding height of the coil 15 is set so that the thickness of the auxiliary core plate 1b is larger than the winding height of the coil 15.

On the other hand, the bearing holder 12 has a hole at the center, and the rotary shaft 13 is inserted into this hole. A cup-shaped rotor case 8 is fixed by press fitting to the outer peripheral surface of the rotary shaft 13 above the portion inserted into the hole of the bearing holder 12. The rotor case 8 has a cylindrical portion that projects toward the bearing holder 12 at the center, and the inner peripheral surface of this cylindrical portion is press-fitted and fixed to the outer peripheral surface of the rotary shaft 13.

A hub base 9 on which various media such as floppy disks are placed is provided on the upper end surface of the rotor case 8. Further, a hole is formed in a part of the hub base 9, and a hole is also formed in the upper end surface of the rotor case 8 in the portion where the hole is formed, and the drive pin 11 is provided.
The drive pin 11 is attached to one end of a swing arm (not shown) provided on the inner surface of the rotor case 8, that is, the surface on the thrust ball bearing 4 side.
Further, the drive pin 11 is formed with a groove 11 a, and the drive pin 11 has a shape in which a part of the rotor case 8 is bitten by the groove 11 a. Therefore, the drive pin 11 is configured to be movable on the upper end surface of the rotor case 8 within a limited range by the swing arm. The drive pin 11 having such a structure plays a role of rotating the floppy disk by engaging with a drive pin insertion hole of a floppy disk (not shown) mounted on the hub base 9.

Further, the rotor case 8 has a circular projecting portion 8a in the shape of a circular jetty at a position facing the washer 4a of the thrust ball bearing 4, and the projecting portion 8a is
The thrust ball bearing 4 is mounted on the upper end surface of the washer 4a. By mounting the protrusion 8a on the upper end surface of the washer 4a of the thrust ball bearing 4, the rotor case 8 and the rotary shaft 13 integrated with the rotor case 8 are moved in the thrust direction by the thrust ball bearing 4. Will be supported, and as a result,
The rotor case 8 and the rotating shaft 13 are rotatable with respect to members such as the substrate 5 which is a stator and the stator core 1.

The rotor case 8 has a peripheral wall on the outer peripheral side, and the driving magnet 2 is provided on the inner surface of the peripheral wall with a yoke 6 interposed therebetween.
Is attached. The drive magnet 2 has a ring shape, and the inner peripheral surface of the stator core 1 is attached to the substrate 5.
It faces the tip surface of the salient pole with a certain gap. Therefore, the drive magnet 2 is magnetically biased in the circumferential direction by controlling the energization of the coil 15 wound around the salient poles of the stator core 1, so that the rotor case 8, the hub base 9,
The rotary shaft 13 is driven to rotate integrally. It should be noted that the rotor 3 is composed of the members of the drive magnet 2, the rotor case 8, the hub base 9, and the rotating shaft 13 which are rotationally driven integrally with each other.

On the other hand, a frequency power generating magnet 7 is attached to the outer peripheral surface of the peripheral wall of the rotor case 8. On the substrate 5, a rectangular wave-shaped frequency power generation pattern (not shown) is provided at a position facing the magnetized surface of the frequency power generation magnet 7. With the rotation of the rotor case 8,
By rotating the frequency power generation magnet 7 facing the frequency power generation pattern, a frequency signal is generated by the frequency power generation pattern. The frequency signal is output to a control device or the like, and the control device controls the rotation speed of the spindle motor.

According to the spindle motor configured as described above, the stator core 1 includes a plurality of core plates 1a having salient poles, and an auxiliary core plate 1b sandwiched between the core plates 1a and the substrate 5. The core plate 1a and the auxiliary core plate 1b are integrally laminated and caulked, and the auxiliary core plate 1b forms a gap around the salient pole and the substrate 5 around which the coil 15 is wound. Since the conventionally used spacer is no longer required and the spacer is not attached, the component cost and the manufacturing cost can be reduced.

Further, since the tongue pieces 1c, 1d, 1e of the auxiliary core plate 1b of the stator core 1 are used as guide portions, and the thrust ball bearings 4 can be mounted on the substrate 5 by using these guide portions as guides, the thrust ball bearing 4 can be mounted on the substrate 5. The thrust ball bearing 4 as the bearing means can be attached with high accuracy. Therefore, the rotation accuracy of the spindle motor can be dramatically improved.

The plate thickness of the auxiliary core plate 1b which is a part of the stator core 1 may be the same as or different from that of the other core plates 1a. The plate thickness may be set to an appropriate value depending on the amount of the coil 15 wound around the salient pole of the stator core 1. Further, the material of the auxiliary core plate 1b and the material of the core plate 1a may be the same or different from each other.

The spindle motor according to the present invention is used in addition to a floppy disk drive motor, a hard disk drive motor, various disk drive motors,
It can be applied as a motor for various other purposes.

[0027]

According to the invention described in claim 1, the stator core is composed of a plurality of core plates having salient poles and an auxiliary core plate sandwiched between the core plates and the substrate. Since the core plate and the auxiliary core plate are integrally caulked and the gap is formed between the salient pole and the substrate, a gap for winding is formed between the substrate and the core plate. Since the spacer is unnecessary, it is possible to reduce the component cost and the manufacturing cost accordingly.

According to a second aspect of the present invention, the bearing means includes a thrust ball bearing having a ball and a washer to support the thrust load of the rotor, and the auxiliary core plate projects inward in the radial direction and the thrust ball bearing. Since the washer is provided with the guide portion for guiding the washer in the radial direction, the thrust ball bearing can be accurately arranged on the substrate, and the rotation accuracy of the spindle motor can be dramatically improved.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a stator core applied to the above spindle motor.

FIG. 3 is a sectional view of the same.

FIG. 4 is a plan view showing an auxiliary core plate applied to the above spindle motor.

FIG. 5 is a sectional view showing an example of a conventional spindle motor.

[Explanation of symbols]

 1 Stator Core 1a Core Plate 1b Auxiliary Core Plate 2 Drive Magnet 3 Rotor 4 Bearing Means 5 Substrate

Claims (2)

[Claims] 1. A stator core around which a coil is wound, a drive magnet that is arranged to face the stator core, a rotor that rotates integrally with the drive magnet, bearing means that rotatably supports the rotor, and a substrate that holds the stator core. And a stator motor, wherein the stator core includes a plurality of core plates having salient poles,
An auxiliary core plate sandwiched between the core plate and the substrate, the core plate and the auxiliary core plate are integrally laminated and caulked, and a gap is formed between the salient pole and the substrate. A spindle motor characterized by being formed with. 2. The bearing means comprises a thrust ball bearing having a ball and a washer for supporting a thrust load of the rotor, the auxiliary core plate protruding radially inward, and a washer of the thrust ball bearing. The spindle motor according to claim 1, further comprising a guide portion that guides the blade in a radial direction.