JPH0951649A - Motor for driving disc - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor for driving a disc in which run-out of a core plane can be prevented without requiring any mechanism for suppressing run-out of the core. SOLUTION: The motor for driving a disc comprises a rotary shaft 2, a hub base 4 secured to one side of the rotary shaft 2, a rotor case 5 fixed integrally with the hub base 4, and a sintered oil retaining bearing 3 for the rotary shaft 2, wherein a sliding plate 7 is provided on the bearing side end face of hub base 4 such that the sliding plate 7 can slide on the end face of sintered oil retaining bearing 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive motor applicable to, for example, a floppy disk drive device.

[0002]

2. Description of the Related Art Conventional examples of disk drive motors used in, for example, floppy disk drive devices are shown in FIGS. The disk drive motor shown in FIG.
The ball bearing 22 is used as a bearing when rotating a rotating body such as the rotor 1, the rotor case 24, and the drive magnet 25 with respect to the rotating shaft (spindle) 20. That is, the load in the thrust direction of this rotating body is received by the ball bearing 22. In FIG. 5, a fixed body composed of a stator core 26, a coil 27, etc. is supported on the substrate 28 by screws 28a. Here, this type of ball bearing 22 is
Although there is no problem in terms of performance, since it is expensive, it has caused a rise in the cost of the bearing portion.

Therefore, there has been proposed a disk drive motor in which the cost is reduced by using a sintered oil-impregnated bearing (metal bearing) instead of a ball bearing. A conventional example of this type of disk drive motor is shown in FIG. In FIG. 6, the sintered oil-impregnated bearing 3 is provided on the substrate 38.
2 are installed. Here, the sintered oil-impregnated bearing 32 has a hole 32a for the rotary shaft 30 in the center. Further, the rotating shaft 30, the hub base 31 fixed to the rotating shaft 30, the rotor case 34 fixed to the hub base 31, and the rotor case 34.
A rotary body composed of a drive magnet 35 and the like fixedly attached to is rotatably held by a sintered oil-impregnated bearing 32.

[0004]

However, in the case of a disk drive motor using the above-mentioned conventional sintered oil-impregnated bearing, the clearance existing between the sintered oil-impregnated bearing and the rotary shaft causes the rotation shaft of the rotary shaft to move when the motor is driven. Center runout occurs, and this causes surface runout on the hub base attached to the rotary shaft. Such runout of the core surface causes a signal reading error of a disc in an FDD made by using the disc driving motor.

Therefore, in order to prevent such a core runout, for example, the magnetic centers of the stator core supported on the substrate supporting the sintered oil-impregnated bearing and the drive magnet of the rotor case may be shifted (rotor biased). (Magnet structure), or a core runout suppressing mechanism that mechanically applies a lateral pressure to the rotary shaft by the sintered oil-impregnated bearing must be provided, which causes a cost increase.

An object of the present invention is to provide a core runout suppressing mechanism,
It is an object of the present invention to provide a disk drive motor capable of preventing the above-mentioned core surface runout.

[0007]

According to the first aspect of the present invention,
Includes a rotating shaft, a hub base for mounting a disk fixed to one side of the rotating shaft, a rotor case integrally attached to the hub base, and a sintered oil-impregnated bearing that rotatably supports the rotating shaft. A disk drive motor, characterized in that a sliding plate is provided on the bearing-side end surface of the hub base, and the sliding plate and the end surface of the sintered oil-impregnated bearing slidably contact each other. is there.

According to a second aspect of the present invention, a rotating shaft, a hub base on which a disk fixed to one side of the rotating shaft is mounted, a rotor case integrally attached to the hub base, and a rotating shaft are rotated. A disk drive motor having a freely supported sintered oil-impregnated bearing, characterized in that the bearing-side end surface of the hub base and the end surface of the sintered oil-impregnated bearing are slidably in contact with each other. is there.

According to a third aspect of the present invention, the hub is formed by a magnetic attraction force between the drive magnet fixed to the outer circumference of the rotor case attached to the hub base and the iron substrate provided on the outer circumference of the sintered oil-impregnated bearing. The structure is characterized in that the table is pressed against the sintered oil-impregnated bearing side.

The end surface of the hub base on the bearing side and the end surface of the sintered oil-impregnated bearing are slid directly or indirectly via a sliding plate. As a result, the hub base rotates by being pressed against the end surface of the sintered oil-impregnated bearing directly or through the sliding plate, so that the surface runout of the hub base due to the runout of the rotating shaft as in the prior art does not occur.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a disk drive motor according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a disk drive motor according to an embodiment. In this disk drive motor, as shown in the drawing, a bearing holder 13 is fitted in a hole 8a formed in the center of an iron substrate 8 and the bearing holder 1
A sintered oil-impregnated bearing 3 is fixed to the inner side of the bearing 3 by a stepped portion 13a of the bearing holder 13 which prevents the bearing from falling out in the figure. The upper part of the sintered oil-impregnated bearing 3 is a thrust receiving portion 3b, and the end surface of the thrust receiving portion 3b is a sliding surface 3d on which a sliding plate 7 described later slides. The stator core 11 is located on the outer periphery of the bearing holder 13, and the stator core 11 is fixed to the substrate 8 by the screws 10.
It is fixed to.

The stator core 11 is formed by laminating a plurality of magnetic plates, has a plurality of salient poles on the outer circumference, and a coil 12 is wound around each salient pole. The inner peripheral edge of the magnetic plate forming the stator core 11 is extended to the sintered oil-impregnated bearing 3 side, and the tip of this extended portion is in contact with the outer peripheral surface of the bearing holder 13. .

The rotary body 1 is rotatably supported on the upper end surface of the sintered oil-impregnated bearing 3. The rotating body 1 includes a rotary shaft 2 inserted through a hole 3a of a sintered oil-impregnated bearing 3, a hub base 4 fixed to an upper end of the rotary shaft 2, and a rotor case mounted on the outer peripheral surface of the hub base 4 by caulking or the like. 5, rotor case 5
The inner surface of the peripheral wall is composed of a driving magnet 6 and the like. The rotor case 5 has a cup shape,
The stator core 11 is covered from above. Further, the inner peripheral surface of the drive magnet 6 is spaced from the stator core 1 by a certain gap.
It faces the outer peripheral surface of 1.

Various media such as a floppy disk are placed on the hub base 4. A sliding plate 7 formed by applying Teflon processing to stainless steel or the like is attached to the outer periphery of the rotary shaft 2 below the hub base 4. The lower end surface of the sliding plate 7 is in contact with the sliding surface 3d of the sintered oil-impregnated bearing 3, and the hub base 4 is placed on the sintered oil-impregnated bearing 3.

As shown in FIG. 2, the hub base 4 has a recess 4b on the lower end surface for storing the sliding plate 7.
The storage portion 4b has a circular shape and has groove portions 4a and 4a 'extending outward from the lower end surface of the hub base 4 on both sides. Also,
The sliding plate 7 is also circular and has two protruding pieces 7b and 7b 'on both sides.
have. Therefore, the sliding plate 7 is mounted in the storage portion 4b, and the protruding portions 7b and 7b 'are attached to the groove portions 4a and 4a'.
The sliding plate 7 is held by the hub base 4 without rotating by being fitted into the hub base 4.

The rotating body 1 has a rotating shaft 2 forming a part thereof.
Are supported in the radial direction by the inner peripheral surface of the hole 3a of the sintered oil-impregnated bearing 3. Further, the sliding plate 7 of the hub base 4 attached to the upper end of the rotary shaft 2 contacts the upper end surface of the thrust receiving portion 3b, that is, the sliding surface 3d, is supported in the thrust direction, and is rotatable. There is. Therefore, the stator core 1
By energizing the coil 12 wound around 1 and energizing the drive magnet 6 by the magnetic force generated at that time, the hub base 7 rotates together with the sliding plate 7 sliding on the sliding surface 3d. The rotating body 1 is driven to rotate. At that time, the hub base 4
The hub base 4 is pressed to the side of the sintered oil-impregnated bearing 3 by the magnetic attraction force between the drive magnet 6 fixed to the outer periphery of the rotor case 5 attached to the rotor and the substrate 8 provided on the outer periphery of the sintered oil-impregnated bearing 3. Will be done.

According to the disk drive motor having the above-described structure, the end surface of the hub base 4 on the side of the sintered oil-impregnated bearing 3 and the end surface of the sintered oil-impregnated bearing 3 slide through the sliding plate 7. Further, the hub base 4 is structured so as to rotate by being pressed against the end surface of the sintered oil-impregnated bearing 3 through the sliding plate 7. Therefore, the surface runout of the hub base 4 due to the runout of the rotating shaft is eliminated, and thus the value of the runout can be suppressed to a small value without the conventional runout suppressing mechanism.

As the sintered oil-impregnated bearing 3 used in the disk drive motor, the one shown in FIG. 3 may be used. In FIG. 3, a plurality of recesses 3c are formed on the end surface of the thrust receiving portion 3b of the sintered oil-impregnated bearing 3, that is, on the sliding surface 3d.
Are formed. Further, the surface of the sliding surface 3d has a concave portion 3
Blinding is applied except for c. Since the sliding surface 3d that has been crushed improves the slidability of the sliding plate 7,
The rotating body 1 can be smoothly driven to rotate even when the motor rotates at a low speed. Further, the insides of the plurality of recesses 3c formed on the sliding surface 3d are not crushed, and innumerable pores are exposed. Therefore, the lubricating oil contained in the sintered oil-impregnated bearing 3 can be supplied from the recess 3c to the sliding surface 3d, and the frictional force between the hub base 4 and the sliding surface 3d can be further reduced, resulting in extremely smooth operation. You can get the rotation.

Further, in the above embodiment, the sliding plate 7 was fitted into the housing portion 4b of the hub base 4, but the invention is not limited to this. It may be integrated with the hub base 4 by insert molding or the like, or may be attached to the hub base 4 by welding.

Further, FIG. 4 shows a main part of another embodiment. This embodiment has the same structure as that of the embodiment of FIG. 1 except that the bearing holder portion is integrally formed with the sintered oil-impregnated bearing 3 in the embodiment of FIG. In addition, this FIG.
In the case, the surface of the sintered oil-impregnated bearing 3 other than the sliding portion with the sliding plate 7 is subjected to the same crushing as described above.

In the above, the sliding plate provided on the bearing side end surface of the hub base and the sintered oil-impregnated bearing are slid, but in addition, the bearing side end surface of the hub base is not provided. It is also possible to have a structure in which the end surface of the sintered oil-impregnated bearing is directly slid.

The present invention is not limited to the configuration described above, and various modifications can be made. For example, a rotor bias magnet structure may be used in which the magnetic centers of the stator core 11 and the drive magnet 6 are slightly shifted to the right or left in FIG. 1, for example.

[0024]

According to the present invention, the end face of the hub base on the bearing side and the end face of the sintered oil-impregnated bearing are slid directly or indirectly via the sliding plate, and the hub base is directly or via the sliding plate. The sintered oil-impregnated bearing was pressed against the end face to rotate. For this reason, the surface runout of the hub base due to the runout of the rotating shaft as in the past does not occur, and the hub base part accuracy, that is, the parallelism between the end surface of the bearing side of the hub base and the end surface of the sintered oil-impregnated bearing causes The run-out is decided. Therefore, it is possible to suppress the value of the surface runout to a small value without the conventional core runout suppressing mechanism.

[Brief description of drawings]

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

FIG. 2 is an explanatory view showing a main part of the disk drive motor of FIG.

3 is a sectional view showing an example of a sintered oil-impregnated bearing used in the disk drive motor of FIG.

FIG. 4 is a sectional view of essential parts showing another embodiment of the disk drive motor according to the present invention.

FIG. 5 is a sectional view showing a conventional example of a disk drive motor.

FIG. 6 is a sectional view showing another conventional example of a disk drive motor.

[Explanation of symbols]

 1 Rotating body 2 Rotating shaft 3 Sintered oil-impregnated bearing 4 Hub stand 5 Rotor case 7 Sliding plate

Claims (3)

[Claims] 1. A rotary shaft, a disk mounting hub base fixed to one side of the rotary shaft, a rotor case integrally attached to the hub base, and the rotary shaft rotatably supported. A disk drive motor including a sintered oil-impregnated bearing, wherein a sliding plate is provided on a bearing-side end surface of the hub base, and the sliding plate and the end surface of the sintered oil-impregnated bearing are slidable. A disk drive motor characterized by being in contact with each other. 2. A rotary shaft, a hub base on which a disc fixed to one side of the rotary shaft is mounted, a rotor case integrally attached to the hub base, and the rotary shaft rotatably supported. And a sintered oil-impregnated bearing for driving the disk, wherein a bearing-side end surface of the hub base and an end surface of the sintered oil-impregnated bearing slidably contact each other. motor. 3. The hub base is attached to the hub base by a magnetic attraction force between a drive magnet fixed to the outer periphery of a rotor case attached to the hub base and an iron substrate provided on the outer periphery of the sintered oil-impregnated bearing. 3. The disk drive motor according to claim 1, wherein the motor has a structure of pressing the sintered oil-impregnated bearing side.