JP2947586B2 - Spindle motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a spindle motor for rotating a recording member such as a magnetic disk.

(Conventional technology and its disadvantages)

Generally, a spindle motor includes a housing and a hub member that is rotatable relative to the housing. A rotor magnet is mounted on the hub member, and a stator is disposed facing the rotor magnet.

In recent years, spindle motors of this type have tended to be miniaturized, so that hub members, rotor magnets, and the like have also become smaller.

However, when the size of the rotor magnet is reduced, it is difficult to obtain a large magnetic force, so that a large output (torque) cannot be obtained as a motor. To obtain a large output, an annular magnet (an N pole and an S
A plurality of segment-shaped magnets may be used in place of the magnets having alternating poles. However, when a segment-shaped magnet is used, it becomes difficult to attach these magnets, and a dedicated jig is required.

[Object of the invention]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and a main object of the present invention is to provide a spindle motor capable of easily and reliably mounting a plurality of magnet pieces at predetermined positions.

[Summary of the Invention]

A housing, a hub member made of a magnetic material rotatable relative to the housing, a rotor magnet mounted on the hub member, and a stator disposed opposite to the rotor magnet. In the spindle motor, the rotor magnet is composed of a plurality of permanent magnet pieces, and the hub member is mounted with a magnet holder integrally formed of a synthetic resin.
A partition wall provided with an annular connecting portion and a guide projection extending substantially vertically at substantially equal intervals in the circumferential direction of the annular connecting portion and projecting at both ends in the circumferential direction at an inner end portion in the radial direction; And the inner peripheral surface of the hub body, the partition wall portion and the guide receiving portion constitute the receiving portion having substantially the same cross-sectional shape as that of the permanent magnet piece, A plurality of permanent magnet pieces
Spindle motors are provided, each being attached to a corresponding one of the receiving portions through an opening in the hub member.

[Specific examples of the invention]

Hereinafter, a specific example of a spindle motor according to the present invention will be described with reference to the accompanying drawings.

In FIG. 1, the illustrated spindle motor includes a substantially circular housing 2 and a hub member 4 rotatable relative to the housing 2. The housing 2 has a plate-shaped main body 6 and a cylindrical wall 8 extending substantially vertically upward from a substantially central portion of the main body 6. The hub member 4 includes a cylindrical hub body 10 and a body.
It has an end wall portion 12 provided at one end (upper end) of 10 and a shaft portion 14 extending substantially vertically downward from the center of the end wall portion 12, and these are integrally formed. In a specific example, the hub member 4 is formed of magnetic stainless steel, and as will be understood from the following description, the hub body 10 also functions as a yoke member. The shaft portion 14 of the hub member 4 is disposed in the cylindrical wall portion 8 of the housing 2, and the shaft portion 14 is disposed on the cylindrical wall portion 8 via a pair of bearing members 16 and 18 which are arranged at intervals in the vertical direction. It is supported rotatably. Between the pair of bearing members 16 and 18, there is further provided a biasing means 20 such as a disc spring for applying a preload thereto.

A rotor magnet is provided on the inner peripheral surface of the main body 10 of the hub member 4.
22 are arranged. The rotor magnet 22 is composed of a plurality (12 in the specific example) of permanent magnet pieces 24 and is mounted on the hub body 10 as described later. A stator 26 is provided inside the rotor magnet 22. The stator 26 has a stator core 28 mounted on the outer peripheral surface of the cylindrical wall portion 8 of the housing 2, and an armature coil 30 is wound around the stator core 28 as required. The main body 10 of the hub member 4 is also provided with a projection 32 projecting outward in a substantially L-shape on the outer peripheral surface, and the projection 32 is provided on the outer peripheral portion of the main body 4 of the housing 2. A labyrinth seal structure is formed in cooperation with the provided concave portion. Also, the bearing member 18
A sealing cap member 36 is mounted on the outside of the housing 2, and a flexible board 38 for a motor is provided on the lower surface of the main body 6 of the housing 2.

In such a spindle motor, the main body 6 of the housing 2 is mounted on a frame (not shown) of a device such as a disk drive, and a recording member (not shown) such as a magnetic disk is mounted on the main body 10 of the hub member 4. Is done. Then, a current is supplied to the amateur coil 30 through the flexible board 38 as required, so that the housing 2
The hub member 4 (and the recording member attached thereto) is rotated in a predetermined direction.

Next, referring to FIGS. 2 and 3 together with FIG. 1,
The manner of mounting the rotor magnet 22 will be described. In a specific example, the inner peripheral surface of the main body 10 of the hub member 4 is formed in a regular dodecagon corresponding to the number of the permanent magnet pieces 24 to be mounted. The magnet holder 40 is mounted on the inner peripheral surface by means such as an adhesive. The magnet holder 40 shown is an annular connection
A partition wall portion 44 is provided at substantially equal intervals between the annular connection portion 42 and the annular connection portion 42. The outer peripheral shape of the annular connecting portion 42 is a regular dodecagon corresponding to the inner peripheral surface shape of the hub body 10, and the inner peripheral shape is circular. Twelve partition walls 44 are provided corresponding to the respective corners of the annular connecting portion 42, and extend substantially vertically downward from the annular connecting portion 42. The thickness of each partition wall portion 44 is gradually reduced from the outside in the radial direction to the inside, and a guide projection projecting to both sides in the circumferential direction is provided at the inner end portion.
46 are provided. The magnet holder 40 can be formed, for example, by integral molding of a synthetic resin.

The magnet holder 40 is mounted on the inner peripheral surface of the hub main body 10 and cooperates with the inner peripheral surface of the hub main body 10, the partition wall 44 and the guide projection 46 as shown in a partially enlarged view in FIG. Then, 12 rectangular receiving portions 48 are defined inside the inner peripheral surface. The permanent magnet pieces 24 have substantially the same shape, and have a rectangular shape corresponding to the shape of the receiving portion 48.

The permanent magnet piece 24 is mounted on the receiving part 48 as follows. That is, as can be easily understood from FIGS. 1 and 3, the permanent magnet piece 24 passes through the opening (located on the lower side in FIG. 1) of the hub member 4 and receives the receiving portion 48 ( Specifically, it is inserted into the inner peripheral surface of the main body 10 and the space defined by the adjacent partition wall 44). And
It is inserted along the receiving portion 48 until one end thereof contacts the annular connecting portion 42. When inserting, insert the permanent magnet piece 24
Is guided by the inner peripheral surface of the hub body 10, the adjacent partition wall 44, and the guide wall 46 provided thereon (ie, the receiving portion 48).
Is substantially the same as that of the permanent magnet piece 24)
Therefore, the permanent magnet piece 24 can be easily mounted, and can be reliably guided to the mounting position. Then, in the mounted state, the movement of the permanent magnet piece 24 in the radial direction, the circumferential direction, and the upward movement are reliably prevented. To reliably prevent the permanent magnet piece 24 from separating,
Its outer surface (the surface that contacts the inner peripheral surface of the hub body 10) and / or
Alternatively, it is preferable to apply an adhesive to both side surfaces (surfaces in contact with the partition wall portion 44) and fix them. In a specific example, as shown in FIGS. 1 and 3, when the permanent magnet pieces 24 are mounted,
The lower end of the permanent magnet piece 24 is substantially flush with the lower end of the hub body 10 and protrudes below the partition wall 46.

As described above, one specific example of the spindle motor according to the present invention has been described. However, the present invention is not limited to such specific example, and various modifications and corrections can be made without departing from the scope of the present invention.

For example, in the specific example shown, the rotor magnet 22 is
Although the permanent magnet pieces 24 are used, the present invention is not limited to this, and it is also possible to use six or eight permanent magnet pieces.

Further, for example, in the illustrated specific example, the outer shape of the connecting portion 42 of the magnet holder 40 is a regular dodecagon, but instead of this,
For example, it can be circular. In this case, the shape of the inner peripheral surface of the hub body 10 is circular, and the permanent magnet pieces 24 are formed.
The outer surface (the surface in contact with the inner peripheral surface) may be formed in an arc shape.

In addition, for example, in the illustrated specific example, the end wall portion 12 and the shaft portion 14 of the hub member 4 are formed integrally, but the end wall portion 12 and the shaft portion 14 are formed separately, and both are formed. You may make it fix by means, such as press fit.

Further, for example, in the illustrated specific example, the present invention is applied to a shaft rotation type spindle motor, but is not limited thereto.
The present invention can be similarly applied to a fixed shaft type spindle motor.

Further, in the specific example shown in the drawings, the present invention is applied to a spindle motor in which a magnetic disk is driven to rotate. However, the present invention can be similarly applied to a spindle motor in which a recording member such as an optical disk is driven to rotate.

〔The invention's effect〕

 According to the present invention, the following effects are achieved.

First, since the rotor magnet is composed of a plurality of permanent magnet pieces, a large magnetic force can be obtained as compared with the case where an annular magnet is used, and high output of the motor is achieved.

Secondly, since the magnet holder is mounted on the hub member and the permanent magnet piece is mounted on the receiving portion defined between the magnet holder and the hub member, the permanent magnet piece is easily and securely mounted on the predetermined position. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a specific example of a spindle motor according to the present invention. FIG. 2 is a sectional view showing a magnet holder of the spindle motor of FIG. 1; FIG. 3 is a partially enlarged perspective view showing a hub member of the spindle motor of FIG. 1 and its vicinity in a partially enlarged manner. 2 ... housing 4 ... hub member 22 ... rotor magnet 24 ... permanent magnet piece 26 ... stator 40 ... magnet holder 44 ... partition wall 48 ... receiving part

Claims (1)

(57) [Claims] 1. A housing, a hub member made of a magnetic material rotatable relative to the housing, a rotor magnet mounted on the hub member, and a rotor magnet opposed to the rotor magnet. And a stator, wherein the rotor magnet is composed of a plurality of permanent magnet pieces; A connecting portion and a partition wall portion extending substantially vertically at substantially equal intervals in the circumferential direction of the annular connecting portion, and provided with guide projections projecting to both circumferential sides at the radially inner end thereof; Wherein the inner peripheral surface of the hub body, the partition wall portion and the guide receiving portion constitute the receiving portion having substantially the same cross-sectional shape as that of the permanent magnet piece. The permanent magnet pieces are A spindle motor attached to the corresponding receiving portion through an opening of the hub member.