JPH06165420A - Spindle motor - Google Patents

Abstract

PURPOSE:To provide a spindle motor where the manufacture of a hub, etc., is easy and the processing time and the cost can be cut down by coupling one end edge of a cylindrical yoke with the peripheral margin of a disclike hub by plastic processing thereby forming a cup-shaped rotor. CONSTITUTION:For a disclike hub 5 consisting of nonmagnetic material such as aluminum or the like, a shallow-pan-shaped circular recess 31 is made at the center of one end face 5a, and also the middle circular peripheral wall 32 is stepped, and a disc 7 is set thereon, and the diametrical positioning is performed. And, one end 11 of a cylindrical yoke 1 is abutted against the peripheral margin of the hub 5, and both are coupled by applying plastic processing such as calking, press, etc., to one part of the peripheral margin so as to form a cup-shaped rotor 12. As a result, the cup-shaped rotor 12 can be formed easily merely by abutting the cylindrical yoke 10 against the disclike hub 5 and coupling them, making use of the plastically processed hub, and besides, since the hub 5 is the shape of a disc easy of processing, even a small-sized one can be manufactured easily, and the processing time and the cost can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor.

[0002]

2. Description of the Related Art In a conventional spindle motor, as shown in FIG. 5, a hub d has a bowl shape in order to bring an outer peripheral surface of a stator b fixed to a housing a and an inner peripheral surface of a rotor magnet c close to and face each other. The yoke f is fixed to the inner surface of the outer peripheral wall e, and the rotor magnet c is attached to the yoke f.

[0003]

However, since the hub d is formed in a bowl shape by shaving a material such as aluminum, there is a problem that it takes time to process and the cost is high.

In addition, with the recent trend toward miniaturization of motors, the hubs have also been miniaturized, and it has become more difficult to manufacture by the above-mentioned shaving.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned conventional problems and provide a spindle motor in which a hub or the like can be easily manufactured and the processing time and cost can be reduced.

[0006]

In order to achieve the above object, a rotor magnet is fitted and fixed inside a cylindrical yoke made of a magnetic material, and the cylindrical shape is formed on the outer peripheral edge of a disk-shaped hub. The bowl-shaped rotor is formed by connecting one end edge portion of the yoke by plastic working.

[0007]

Since the bowl-shaped rotor can be easily formed only by connecting the cylindrical yoke to the disk-shaped hub by plastic working, it is not necessary to form the hub into the bowl-shaped shape due to time-consuming shaving of the material.

Further, since the hub is disc-shaped, it is easy to manufacture even a small one.

[0009]

The present invention will be described in detail below with reference to the drawings showing the embodiments.

FIG. 1 illustrates a sectional view of a spindle motor according to the present invention. Reference numeral 1 denotes a cylindrical housing made of aluminum or the like.

2 is a stator, and this stator 2 is
The stator core 3 and the stator coil 4 wound around the stator core 3 are fixed to the outer periphery of the housing 1.

Reference numeral 5 is a disk-shaped hub made of a non-magnetic material such as aluminum. On one end face 5a of the hub 5, a shallow dish-shaped circular recess 31 is formed in the center, and a circumferential wall portion 32 having an intermediate outer diameter is formed in a stepped shape. The disk 7 (shown in phantom) is inserted. That is,
The circumferential wall portion 32 is inserted into the hole portion of the disk 7 for radial positioning.

Reference numeral 6 denotes an annular projecting ridge projecting from a flat surface portion 33 formed on the outer diameter side of the circumferential wall 32, and the narrow top portion (annular shape) of the projecting ridge 6 is formed. ) Is the contact surface 8 of the disk 7. The disk 7 is held by the clamp 34.

A cylindrical yoke 10 is provided on the outer peripheral edge of the hub 5.
The bowl-shaped rotor 12 is formed by abutting the one end edge portion 11 of the above and by plastically working a part of the outer peripheral edge portion by caulking or pressing.

The yoke 10 is made of a magnetic material, and the rotor magnet 9 is fitted and fixed to the inner peripheral surface thereof. In the illustrated example, one end edge portion 11 of the yoke 10 is bent in the inner diameter direction to have an L-shaped cross section.

The solid line in FIG. 2 shows the state before the yoke 10 and the hub 5 are connected, and the other end surface 5b of the hub 5 is formed with a plastically deformable circular peripheral wall-shaped projection 13 shown by the solid line. There is. (Note that the projections 13 may be formed in a proper number as projections at a predetermined pitch in the circumferential direction.)

The inner brim-shaped one end edge portion 11 of the yoke 10 is brought into contact with the outer peripheral edge surface 14 of the hub 5 and the outer surface base end portion of the protruding portion 13, and the protruding portion 13 is swaged in the direction of the arrow. By plastically deforming it and press-contacting the one end edge portion 11 as shown by an imaginary line,
A yoke 10 can be connected to the hub 5.

In addition to the illustrated example, one end edge portion 11 of the yoke 10
It is also free to form a structure in which the outer flange portion is formed by bending in the outer diameter direction, and a part of the hub 5 is connected to this outer flange portion by plastic working.

Although not shown, the other end surface 5 of the hub 5
In b, a protrusion (similar to the protrusion 13 in FIG. 2) is formed into two concentric lines, and the one end edge portion 11 of the yoke 10 which is straight without bending is inserted between the protrusions. Then, it is also possible to freely connect the two by plastic working.

In this way, the yoke 10 and the hub 5 are connected and integrated, and the inner peripheral surface of the rotor magnet 9 and the outer peripheral surface of the stator core 3 face each other with a minute predetermined distance.

Reference numeral 15 denotes a shaft, and in FIG. 1, the shaft 15 is formed by cutting the hub 5 and the hub 5 integrally.
Extends vertically from.

A shaft 15 integral with the hub 5 is rotatably attached to the inner periphery of the housing 1 via a pair of bearings 16, 16. Reference numeral 17 is a cap attached to the inner peripheral edge of one end of the housing 1.

According to the spindle motor of the present invention constructed as described above, however, the bowl-shaped rotor can be easily assembled by simply contacting the cylindrical yoke 10 with the disk-shaped hub 5 and connecting them by plastic working of the hub 5. 12 can be formed.

Moreover, since the hub 5 has a disk shape that can be easily processed, even if it is small, it can be easily manufactured.
Further, when the shaft 15 and the hub 5 are integrally formed, if an aluminum material is used as the material, workability such as cutting is good and there is an advantage that the cost is low.

Next, FIG. 3 shows another embodiment of the hub 5.
The structure in which the shaft 15 and the shaft 15 are separately formed and then connected and integrated is illustrated.

In this case, as shown in FIG. 4, the hub 5 is
The shaft 15 is formed in a flat plate annular shape having a connecting hole 18, and the shaft 15 is formed to have a flange portion 19.

The flange portion 19 has a stepped portion 20 for preventing the hub from coming off on the outer peripheral surface thereof, and the hub 5 has a stepped corresponding portion 21 corresponding to the stepped portion 20 in the connecting hole 18. There is.

The outer peripheral surface of the flange portion 19 is fitted into the connecting hole 18 of the hub 5 by press fitting or shrink fitting, and the step portion 20 and the step corresponding portion 21 are contacted with each other as shown in FIG. Contact and integrate.

As described above, since the stepped portion 20 and the stepped corresponding portion 21 are brought into contact with each other and the hub 5 and the shaft 15 are fitted to each other, the hub 5 and the shaft 15 are different from each other when their thermal expansion coefficients are different from each other. Even if the coupling surface loosens (gap) due to the difference in thermal expansion with the hub 15, the arrow A of the hub 5 with respect to the shaft 15
There is an advantage that it can be prevented from slipping out in the direction.

As the material of the hub 5 and the shaft 15, for example, an aluminum material is used for the hub 5 and a steel material is used for the shaft 15.
-For example, SUM24L whose surface is plated is used.

In this case, the strength of the shaft supporting portion of the bowl-shaped rotor 12, that is, the shaft 15, is increased, and there is an advantage that vibration can be prevented from occurring when the rotor rotates.

Alternatively, the shaft 15 is made of stainless steel
Using SUS303 or the like, for example, increases the strength in the same way as when using the above steel materials, and, in manufacturing, has good workability such as cutting, has a small coefficient of thermal expansion, and has tolerance control. It has the advantage of being easy.

In the embodiment shown in FIG. 1 or FIGS. 3 and 4 described above, it is desirable that the housing 1 is made of the same material as the shaft 15, and between the inner ring 23 and the outer ring 24 of the bearing 16 due to the difference in thermal expansion. It is possible to prevent the slippage of the preload and prevent the preload loss.

[0034]

Since the present invention is constructed as described above, it has the following great effects.

The bowl-shaped rotor 12 can be easily formed only by connecting the cylindrical yoke 10 to the disk-shaped hub 5 by plastic working.
Therefore, it is not necessary to form the hub into a bowl shape by shaving out the material that takes time, and the processing time and cost can be reduced.

In addition, since the hub 5 has a disk shape that can be easily processed, it is particularly effective when it is difficult to manufacture the hub due to downsizing of the motor.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing a state before the hub and the yoke are connected.

FIG. 3 is a sectional view showing another embodiment.

FIG. 4 is a cross-sectional view showing a state before the hub and the shaft are connected.

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

[Explanation of symbols]

 5 hub 9 rotor magnet 10 yoke 11 one end edge 12 bowl-shaped rotor

Claims (1)

[Claims] 1. A rotor magnet 9 is fitted and fixed inside a cylindrical yoke 10 made of a magnetic material, and one end edge portion 11 of the cylindrical yoke 10 is attached to an outer peripheral edge portion of the disk-shaped hub 5.
A spindle motor characterized in that the bowl-shaped rotor 12 is formed by connecting the above by plastic working.