JPH04208052A - Spindle motor - Google Patents

Abstract

PURPOSE:To easily manage the prepressure to be applied to bearing means by securing one inner sleeve to the shaft of a hub member, relatively movably mounting the other inner sleeve at the shaft, and applying a predetermined pressure to the other sleeve. CONSTITUTION:One inner sleeve 14 is secured to a large-diameter part 28 of a shaft 26, and the other inner sleeve 16 is axially movably mounted at a small- diameter part 30 of the shaft 26. The lower end of an outer sleeve 12 is secured to a bracket 2. Prepressure applying means 44 has a pair of leaf spring members 46, and the springs 46 are interposed between an engaging ring 48 mounted at the free end of the shaft 26 and the sleeve 16. Prepressure from the means 44 is transmitted from the sleeve 16 to the sleeve 12 through a spherical member 20, further transmitted to the sleeve 14 through a spherical member 18, and prepressure is applied, as prescribed, to bearing means 6. The spring 46 is altered to regulate the prepressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a spindle motor that rotationally drives a recording member such as a magnetic disk.

[Prior art and its drawbacks]

For example, a spindle motor includes a bracket and a hub means that is rotatable relative to the bracket, and a pair of bearing members is interposed between the bracket and the hub means. However, since conventional spindle motors use a pair of bearing members, the structure of the motor itself becomes complicated and it is difficult to reduce its size.

Therefore, in order to solve the problem mentioned above, the applicant proposed a spindle motor using a new bearing means. The bearing means in such a spindle motor includes a shaft member fixed to a bracket, an outer sleeve disposed outside the shaft member, and two sets of spherical members interposed between the shaft member and the outer sleeve. There is. However, in this improved spindle motor, since two sets of spherical members are incorporated between the shaft member and the outer sleeve, it is difficult to control the preload applied to the spherical members, and there is a problem that the preload varies.

[Purpose of the invention]

The present invention has been made in view of the above facts, and its main purpose is to provide an excellent spindle motor that has a relatively simple configuration and whose preload can be easily managed.

[Summary of the invention]

In the spindle motor of the present invention, the bearing means is interposed between the outer sleeve, the pair of inner sleeves spaced apart in the axial direction inside the outer sleeve, and the outer sleeve and the pair of inner sleeves. the outer sleeve is attached to the bracket, and the pair of inner sleeves are attached to a shaft portion provided on the hub member.

Further, in the spindle motor of the present invention, the bearing means includes an outer sleeve, a pair of inner sleeves arranged at intervals in the axial direction inside the outer sleeve, and a space between the outer sleeve and the pair of inner sleeves. a plurality of spherical members interposed in;
The outer sleeve is attached to the hub member, and the pair of inner sleeves are attached to the shaft portion provided on the bracket.

In such a spindle motor, a spherical member is interposed between an outer sleeve and a pair of inner sleeves, so one inner sleeve is fixed to the shaft of the hub member (or bracket), and the other inner sleeve is fixed to the shaft of the hub member (or bracket). By applying a predetermined pressure to the other inner sleeve, a desired preload can be applied to the bearing means. management is very easy.

[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.

East Yu! A specific example of the spindle motor according to the present invention will be described with reference to FIG.

In FIG. 1, the illustrated spindle motor includes a bracket 2, a hub member 4, and a bearing means 6 interposed between the bracket 2 and the hub member 4. Bracket 2
has a substantially circular bracket main body 8. A flange portion 10 (only a portion of which is shown) is provided at the peripheral edge of the bracket body 8, and this flange portion 10 is attached to a frame (not shown) of a drive device.

The bearing means 4 includes a cylindrical outer sleeve 12 and a pair of inner sleeves 14 and 1 disposed inside the outer sleeve 12.
6, and these inner sleeves 14 and 16 are spaced apart in the axial direction (in the vertical direction in FIG. 1). A plurality of spherical members 18 are mounted between one end of the outer sleeve 12 and one of the inner sleeves 14 so as to be movable and rotatable in the circumferential direction, and between the other end of the outer sleeve 12 and the other inner sleeve. Also between the sleeve 16, a plurality of spherical members 20 are mounted so as to be movable and rotatable in the circumferential direction. In the specific example, as shown in FIG. It is set somewhat smaller than the diameter. The outer diameter of the outer sleeve 12 is substantially the same over its entire length.
- identical, but the inner diameter of one inner sleeve 14 is larger than the inner diameter of the other inner sleeve 16;

In this way, by changing the diameters of the upper and lower spherical members 18 and 20, the resonance point of vibration can be shifted, and vibration and noise can be reduced.

In the specific example, an annular sealing member 21 is also disposed at the upper end of the outer sleeve 12. This sealing member 21 prevents particles of grease or the like filled in the receiving grooves of the spherical members 18 and 20 from leaking to the outside.

The hub member 4 includes a substantially cylindrical hub body 22. An end wall 24 is provided at one end (upper end) of the hub body 22, and a shaft 26 extending downward in FIG. 1 is integrally provided at the center of the inner surface of the end wall 24. In a specific example,
The shaft portion 26 has a large diameter portion 28 extending from the end wall portion 24 and a small diameter portion 30 extending from the large diameter portion 28, and is formed integrally with the end wall portion 24. Note that the shaft portion 26 may be formed separately from the end wall portion 24 and fixed thereto. A flange portion 32 that projects radially outward is formed at the other end of the hub body 22 . A plurality of recording members (not shown) such as magnetic disks are placed on the L surface of the flange portion 32 via spacers (not shown).

An annular rotor magnet 36 is attached to the inner peripheral surface of the hub body 22 via a yoke member 34. A stator 38 is arranged opposite the rotor magnet 36.

The stator 38 has a stator core 40 formed by laminating metal plates, and a coil 42 is wound around the stator core 40 as required. In the specific example, the stator core 40 is attached to the outer peripheral surface of the outer sleeve 12 fixed to the bracket body 8, but instead of this configuration, an annular support wall is formed on the bracket body 8,
The stator core 40 may be attached to the outer peripheral surface of this annular support wall.

With this structure, when a required current is supplied to the coil 42 of the stator 38, the hub member 4 is rotated in a predetermined direction by the action of the stator 38 and the rotor magnet 36, thereby causing a recording member (not shown) to rotate. are also rotated together.

In such a spindle motor, preload to the bearing means 6 is applied as follows.

In the specific example, one inner sleeve 14 is fixed to the large diameter portion 28 of the shaft portion 26 by hand using adhesive or the like, while the other inner sleeve 16 is axially movable to the small diameter portion 30 of the shaft portion 26. It will be installed. Further, the lower end portion of the outer sleeve 12 is fixed to the bracket 2 by means such as press fitting. Furthermore, preload applying means 44 are arranged in connection with the movable inner sleeve 16 . The illustrated preload applying means 44 has a pair of disc spring members 46, and the disc springs 46 are interposed between a locking ring 48 attached to the free end of the shaft portion 26 and the inner sleeve 16. Since the preload applying means 44 is thus provided,
The preload from the preload applying means 44 is transmitted from the inner sleeve 16 to the outer sleeve 12 via the spherical member 20, and further to the inner sleeve 14 via the spherical member 18, thus applying the required preload to the bearing means 6. In particular, the preload can be adjusted by changing the countersunk 46.

! Next, with reference to FIG. 2, a second specific example of the spindle motor according to the present invention will be described.

In this second specific example, the present invention is applied to a fixed shaft type. In FIG. 2, members that are substantially the same as those in FIG. 1 are given the same numbers.

In FIG. 2, the spindle motor of the second specific example is also
It includes a bracket 2, a hub member 4, and bearing means 6. A shaft portion 52 is integrally provided approximately at the center of the bracket 2, and this shaft portion 52 extends substantially vertically upward from the bracket body 8.

In the second specific example as well, the shaft portion 52 has a large diameter portion 54 extending from the bracket main body 8 and a small diameter portion 56 further extending from the large diameter portion 54. Further, the hub member 4 has a cylindrical hub body 22, and an end wall portion 2 is provided at one end of the hub body 22.
4, and a circular hole is formed in the center of this end wall portion 24. The bearing means 6 of the second embodiment are of substantially the same construction as those of the first embodiment, and the outer sleeve 1
2, a pair of inner sleeves 14 and 16 disposed inside the outer sleeve 12, and a plurality of spherical members 18 and 20 disposed between them.

This bearing means 6 can be constructed as a unit.

In a second embodiment, the bearing means 6 are mounted as follows. That is, one inner sleeve 14 is connected to the large diameter portion 52 of the shaft portion 52.
The other inner sleeve 16 is attached to the outer circumferential surface of the small diameter portion 56 of the shaft portion 52 so as to be movable in the axial direction.

Furthermore, a stator 3 is provided on the outer peripheral surface of one end of the outer sleeve 12.
8 is attached, and the hub member 4 is fixed to the outer peripheral surface of the other end. Further, the free end of the shaft portion 52 is provided with a preload applying means 44 consisting of a locking member 48 and a pair of disc springs 46, similar to the first embodiment. In the second specific example, a disk-shaped cap member 58 is further attached to the other end of the outer sleeve 12 of the bearing means 6 in order to prevent the lubricating grease from scattering.

As is easily understood, even in this second embodiment, a desired preload can be applied to the bearing means 6, and the control of this preload is extremely easy, and the motor itself is easy to assemble.

Although specific examples of the spindle motor according to the present invention have been described above, the present invention is not limited to such specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

〔Effect of the invention〕

According to the spindle motor of the present invention, since the spherical member is interposed between the outer sleeve and the pair of inner sleeves, one inner sleeve is fixed to the shaft of the hub member (or bracket), and the other inner sleeve is fixed to the shaft of the hub member (or bracket). A desired preload can be applied to the bearing means by mounting the sleeve so as to be movable relative to the shaft portion and applying a predetermined pressure to the movable inner sleeve. Regardless of the phrase, preload management is very easy.

[Brief explanation of the drawing]

The first diagram is a sectional view showing a first specific example of the spindle motor according to the present invention. FIG. 2 is a sectional view showing a second specific example of the spindle motor according to the present invention. 2... Bracket] 4... Hub member 6... Bearing means 12... Outer sleeves 14 and 16... Inner sleeves 18 and 20... Spherical member 36... Rotor magnet 38...・Stator 44...Preload applying means patent applicant Nidec Corporation representative Shigenobu Mizumori

Claims (1)

[Claims] 1. A bracket, a hub member to which a recording member is attached,
a bearing means interposed between the bracket member and the hub member; a rotor magnet attached to the hub member;
a stator disposed opposite to the rotor magnet;
In the spindle motor, the bearing means includes an outer sleeve, a pair of inner sleeves spaced apart in the axial direction inside the outer sleeve, and an outer sleeve and the pair of inner sleeves. a plurality of spherical members interposed between the two, the outer sleeve being attached to the bracket, and the pair of inner sleeves being attached to a shaft portion provided on the hub member. spindle motor. 2. A bracket and a hub member to which the recording member is attached;
a bearing means interposed between the bracket member and the hub member; a rotor magnet attached to the hub member;
a stator disposed opposite to the rotor magnet;
In the spindle motor, the bearing means includes an outer sleeve, a pair of inner sleeves spaced apart in the axial direction inside the outer sleeve, and an outer sleeve and the pair of inner sleeves. a plurality of spherical members interposed between the two, the outer sleeve being attached to the hub member, and the pair of inner sleeves being attached to a shaft portion provided on the bracket. spindle motor. 3. The spherical member interposed between one end of the outer sleeve and one of the pair of inner sleeves, and the other end of the outer sleeve and the other of the pair of inner sleeves. 3. The spindle motor according to claim 1, wherein the spherical member has a different diameter.