JPH06185524A - Bearing device - Google Patents

Abstract

PURPOSE:To provide a bearing device with no necessity for additionally providing a thrust bearing as a separate member by preventing a run-out from being generated in a rotary shaft at the time of rotation. CONSTITUTION:In a bearing device, a rotary shaft 5 fixed to a rotor part is rotatably supported by a bearing 3 held to a housing 2. Tapered parts 12, 13 are formed in at least one side of an opposed part between the bearing 3 and the rotor part, and force in a thrust direction of the rotary shaft 5 is received by the tapered parts 12, 13 to restrict deflection in a radial direction of the rotary shaft 5. Rotary balls 14 for relatively rotating the bearing 3 and the rotor part may be interposed between opposed parts of the bearing 3 and the rotor part. A sliding means for sliding the bearing 3 and the rotor part also may be interposed between the opposed parts of the bearing 3 and the rotor part, and a coating of low friction coefficient may be applied to a sliding surface of the sliding means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device which can be applied to, for example, a floppy disk drive motor or the like and can eliminate core runout.

[0002]

2. Description of the Related Art For example, in a motor for a floppy disk drive, it is extremely reluctant to cause runout of the spindle at the time of rotation, but it is difficult to eliminate the runout of the spindle according to the conventional bearing structure. The reason will be described with reference to an example of a conventional floppy disk drive motor shown in FIG.

In FIG. 20, a cylindrical bearing housing 2 is fixed to a substantially central portion of a motor substrate 1 with a thrust bearing 30 having a concave shape interposed between the bearing housing 2 and the substrate 1. Upper and lower sintered oil-impregnated bearings 3 and 4 are fitted in the bearing housing 2, and the rotary shaft is rotatably supported by these bearings 3 and 4. Upper bearing 3
A hub base 6 made of resin is fixed to the upper end of the rotary shaft 5 protruding upward from the above by press fitting. A center hole of a flat cup-shaped rotor case 7 is fixed to the hub base 6, and a ring-shaped rotor magnet 8 is fixed to the inner peripheral side of the peripheral wall of the rotor case 7. A disk hub of a floppy disk is placed on the hub base 6, and the upper end of the rotary shaft 5 is fitted in the hole at the center of the disk hub.

A central hole of the stator core 10 is fitted on the outer peripheral side of the bearing holder 2. The stator core 10 is fixed on the substrate 1 via a spacer 9.
The stator core 10 has a plurality of salient poles, a drive coil 11 is wound around each salient pole, and the outer end surface of each salient pole faces the inner peripheral surface of the rotor magnet 8 with a proper gap. . Each drive coil 11 is divided into an appropriate number of phases, and the rotor portion is rotationally driven by switching the energization to each phase drive coil 11 according to the rotational position of the rotor portion. The substrate 1 is made of a magnetic material such as an iron plate, and a force in the thrust direction is applied to the rotating shaft 5 by an attractive force acting between the rotor magnet 8 and the substrate 1, so that the thrust receiver 30 receives the force in the thrust direction. It has become.

[0005]

In order to rotatably support the rotary shaft 5 by the sintered oil-impregnated bearings 3 and 4 like the conventional bearing structure of the floppy disk drive motor, the sintered oil-impregnated bearing 3 is used. , 4 and the rotary shaft 5 must be provided with a gap. Without this gap, the sintered oil-impregnated bearing 3,
This is because the fit between the rotating shaft 5 and the rotating shaft 5 becomes uncomfortable and the rotating shaft 5 cannot rotate. Therefore, when the rotor portion is rotated, a runout occurs on the rotating shaft 5 in accordance with the above-mentioned clearance. When such a bearing structure is incorporated in a floppy disk drive motor, the floppy disk is eccentrically rotated. In some cases, the relative position between the recording track of the disk and the magnetic head was misaligned, and a tracking error occurred during recording and reading. Further, the eccentricity of the floppy disk increased with the wear of the bearing over time, and the tracking error was more likely to occur.

Further, since it is necessary to provide a gap between the sintered oil-impregnated bearings 3 and 4 and the rotating shaft 5, the sintered oil-impregnated bearings 3 and 4 cannot receive the thrust force, and the thrust bearings It was necessary to add 30 as a separate member.

The present invention has been made in view of the above problems of the prior art. A bearing device in which center runout of a rotating shaft does not occur during rotation and a thrust receiver does not need to be added as a separate member. The purpose is to provide.

[0008]

In order to achieve the above object, the present invention provides a bearing device in which a rotating shaft fixed to a rotor part is rotatably supported by a bearing held in a housing. A taper portion is formed on at least one side of a portion opposed to, and the taper portion receives a force in the thrust direction of the rotary shaft and regulates the runout of the rotary shaft in the radial direction. A rotating ball that relatively rotates the bearing and the rotor portion may be interposed between the facing portions of the bearing and the rotor portion. Alternatively, a sliding means for sliding the bearing and the rotor portion may be interposed between the facing portion of the bearing and the rotor portion, and the sliding means has a coating with a low friction coefficient on the sliding surface. May be given.

[0009]

The taper portion is formed on at least one side of the facing portion of the bearing and the rotor portion, and the taper portion receives a force in the thrust direction of the rotary shaft, so that a centripetal force is exerted in the taper portion to cause the radial direction of the rotary shaft. Is regulated so that the center of the rotating shaft coincides with the center of the bearing. By interposing a rotating ball or a sliding means between the facing portion of the bearing and the rotor portion, the rotor portion smoothly rotates with respect to the bearing.

[0010]

Embodiments of the bearing device according to the present invention will be described below with reference to FIGS. In addition,
The same components as those of the conventional example described in FIG. 20 are designated by the same reference numerals. In FIG. 1, a concave tapered portion 12 is formed on the upper surface side of the sintered oil-impregnated bearing 3 fitted on the upper side of the cylindrical bearing housing 2. On the other hand, in the hub base 6 which constitutes the rotor portion, the rotary shaft 5 is press-fitted into the center hole, and the center hole of the rotor case 7 is integrally fitted to the outer peripheral portion, the hub base 6 has a convex shape on the surface facing the bearing 3. A tapered portion 13 is formed. A thrust force acts on the rotor portion in a direction in which the taper portion 13 of the hub base 6 tries to fit into the taper portion 12 of the bearing 3, but a plurality of rotating balls having the same diameter are provided between the taper portions 12 and 13. 14 are arranged side by side in the circumferential direction, and the thrust balls 14 can receive the force in the thrust direction. When the opening angle of the tapered portion 12 on the bearing 3 side is A and the opening angle of the tapered portion 13 on the hub base 6 side is B, it is desirable to satisfy the relation of A ≧ B.

FIG. 19 shows an example in which the bearing device according to the above embodiment is applied to a floppy disk drive motor. However, the detailed configuration of the bearing device portion is omitted in FIG. The example shown in FIG. 19 has almost the same configuration as the conventional example shown in FIG. 20 except for the bearing device, and the motor substrate 1, the bearing housing 2, the sintered oil-impregnated bearings 3, 4, the rotary shaft 5 are shown. The hub base 6, the rotor case 7, the rotor magnet 8, the spacer 9, the stator core 10, and the drive coil 11 are included. A thrust force acts on the rotor as indicated by the arrow.

Returning to FIG. 1, the thrust force is
The tapered portion 13 on the hub base 6 side is the tapered portion 1 on the bearing 3 side.
2 and the ball 14 are received. When the rotor portion including the rotating shaft 5 rotates, the taper portion 13 on the hub base 6 side and the taper portion 12 on the bearing 3 side make rolling contact with each other while being pressed against each other via the rotating ball 14, so that the hub base 6 and its surroundings are in contact with each other. From the center to the center, that is, the centripetal force works,
As a result, the center of the bearing 3 and the center of rotation of the rotor portion including the rotating shaft 5 and the hub 6 are aligned, and the rotating shaft 5 and the hub 6 are
Radial runout of the rotor portion including the is restricted. Therefore, if the bearing device as shown in FIG. 1 is applied to the floppy disk drive motor shown in FIG. 19, there is no eccentricity of the disk rotation center when the floppy disk rotates,
There is no relative displacement between the disk and the magnetic head, and tracking errors during recording and reading can be eliminated.

Since the bearing 3 and the hub base 6 also serve as a thrust receiver, a gap can be provided between the lower end of the rotary shaft 5 and the substrate 1 as shown in FIG. It need not be provided as a member. When the rotating ball 14 rolls, the rotor portion including the hub base 6 and the rotating shaft 5 is rotated relative to the bearing 3. Since the centripetal force acts as described above, even if the span of the bearing is shortened, the runout of the rotary shaft 5 can be reduced and the thickness can be reduced. The tapered portion 12 of the bearing 3 and the rotating ball 1 are rotated for a long time.
Even if the contact surface with 4 is worn, the hub base 6 is constantly pressed by the rotating ball 14 due to the thrust pressure, so the rotating shaft is always centered, and the thrust receiver must be provided as a separate member as in the conventional case. Since the hub base 6 can move toward the bearing 3 side as it wears, there is no gap between the hub base 6 and the rotating ball 14, and thus no rattling.

Next, various modified embodiments of the present invention will be described. In the embodiment shown in FIG. 2, a taper member 15 is provided integrally with the hub base 6 in place of the taper portion 13 of the hub base 6 of the embodiment shown in FIG. They are the same. The taper member 15 can be made of metal, for example. The taper member 15 may also serve as a holding member for the rotating ball 14.

The embodiment shown in FIG. 3 is an example in which the concavo-convex relationship of the tapered portion between the bearing 3 and the hub base 6 of the embodiment shown in FIG. 1 is reversed. That is, a convex taper portion 16 is formed on the upper end surface of the bearing 3, and a concave taper portion 17 is formed on the lower end surface of the hub base 6 facing the bearing portion 3.
A plurality of rotating balls 14 are interposed between them.

The embodiment shown in FIG. 4 is an example in which the concavo-convex relationship of the taper between the bearing 3 and the taper member 15 of the embodiment shown in FIG. 2 is reversed. That is, a convex taper portion 16 is formed on the upper end surface of the bearing 3, and a concave taper member 18 is integrally formed with the hub base 6 on the lower end surface of the hub base 6 facing the bearing 3. A plurality of rotating balls 14 are provided between the rotating balls 14 and 18.

In the embodiment shown in FIG. 5, a peripheral groove 19 is formed on the upper end surface of the bearing 3, a plurality of rotating balls 14 are arranged in the peripheral groove 19, and a concave taper portion 17 is formed on the lower surface side of the hub base 6. It was formed. The upper half of the rotating ball 14 is exposed from the circumferential groove 19, and the exposed rotating ball 14 is contacted by the taper portion 17 of the hub base 6 to receive a force in the thrust direction and a centripetal force to the rotor portion. It is working.

In all of the embodiments described so far, the rotating ball is interposed between the facing portion of the bearing and the rotor portion, but the sliding means is interposed between the facing portion of the bearing and the rotor portion. Alternatively, the bearing and the rotor portion may be slid. Hereinafter, various embodiments in which sliding means is interposed between the facing portion of the bearing and the rotor portion will be described.

In the embodiment shown in FIG. 6, a tapered taper portion 12 is formed on the upper end surface of the bearing 3, and a convex taper portion 13 is formed on the lower surface side of the hub base 6 facing the tapered taper portion 12 of the bearing 3. As shown in FIG. 7, a tapered sliding member 20 having the same opening angle as that of the tapered portion 12 is fixed to the portion 12, and the tapered portion 12 of the hub base 6 is slid on the sliding member 20. It was done like this. It is desirable to coat the sliding surface of the sliding member 20 with the hub base 6 with a low friction coefficient.

In the embodiment shown in FIG. 8, the concave taper portion 12 formed on the upper end surface of the bearing 3 and the convex taper portion 13 formed on the lower surface side of the hub base 6 are slid directly. The tapered portion 12 of the bearing 3 is provided with a circumferential groove 21 for reducing the sliding surface. The formation of the circumferential groove 21 has an advantage of decreasing the sliding resistance, and the use of the circumferential groove 21 as an oil reservoir can further reduce the sliding resistance. According to this embodiment, there is also an advantage that the number of parts can be reduced.

In the embodiment shown in FIG. 9, the concave taper portion 12 formed on the upper end surface of the bearing 3 and the convex taper portion 13 formed on the lower surface side of the hub base 6 are directly slid. Is. When the bearing 3 is a sintered oil-impregnated bearing, an increase in sliding resistance can be prevented even with the configuration shown in FIG.

In the embodiment shown in FIG. 10, a spherical surface 22 is formed on the lower surface side of the hub base 6 of the embodiment shown in FIG.
Is brought into contact with the concave tapered portion 13 of the bearing 3.

In the embodiment shown in FIG. 11, the concavo-convex relationship of the taper portion in the embodiment shown in FIG. 6 is reversed.
That is, a convex taper portion 16 is formed on the upper end surface of the bearing 3, and a concave taper portion 17 is formed on the lower end surface of the hub base 6 facing the bearing portion 3 so that the taper portion 16 has a convex taper surface. The member 23 is fixed, and the tapered surface 17 of the hub base 6 slides on the upper sliding surface of the sliding member 23.

In the embodiment shown in FIG. 12, a sliding member 24, which is provided integrally with the hub base 6 and forms a concave taper portion, slides on the convex taper surface 16 of the bearing 3. FIG. 13 shows the sliding member 24.

In the embodiment shown in FIG. 14, a concave tapered sliding member 25 is fixed to the concave tapered surface 12 formed on the upper side of the bearing 3, and a convex member integrally provided on the lower surface side of the hub base 6 is provided. The sliding member 26 having a tapered shape is slid on the sliding member 25. A coating 27 having a low coefficient of friction is applied to the upper surface of the sliding member 25.

In the embodiment shown in FIG. 15, the convex tapered sliding member 26 integrally provided on the lower surface side of the hub base 6 is slid directly on the concave tapered surface formed on the upper side of the bearing 3. In addition, the sliding surface is reduced by forming the circumferential groove 27 on the tapered surface. It is not always necessary to provide the circumferential groove 27 on the tapered surface. FIG.
The embodiment shown in is an example in which the circumferential groove 27 is omitted.

In the embodiment shown in FIG. 17, the concavo-convex relationship of the taper of the embodiment shown in FIG. 8 is reversed. That is, the convex tapered surface 16 on the upper side of the bearing 3 is brought into contact with the concave tapered surface 17 on the lower side of the hub base 6 for sliding, and the circumferential groove 27 is provided on the tapered surface 16. Further, the embodiment shown in FIG. 18 has a shape in which the circumferential groove 27 of the embodiment shown in FIG. 17 is omitted.

Also in the embodiment shown in FIGS. 6 to 18 described above, the thrust force acting on the rotor portion is received by at least one of the tapered portions of the bearing 3 and the hub base 6, so that the hub base can be received. A force that directs 6 toward the center side from its periphery, that is, a centripetal force is exerted, whereby the center of the bearing 3 and the rotation center of the rotor portion including the rotating shaft 5 and the hub 6 are aligned, and the rotating shaft 5 and the hub 6 are Radial runout of the rotor unit including the rotor unit is restricted. Therefore, if such a bearing device is applied to the floppy disk drive motor shown in FIG. 19, there is no eccentricity of the disk rotation center during rotation of the floppy disk, and there is no relative positional deviation between the disk and the magnetic head. The tracking error at the time can be eliminated. Besides, Fig. 1
Through the same effect as the embodiment shown in FIG.

The bearing device according to the present invention is not limited to a floppy disk drive motor, but can be applied as a bearing device for a hard disk drive motor and other various disk drive motors, various motors, and general machines other than motors.

[0030]

According to the present invention, since the thrust force acting on the rotor portion is received by at least one of the tapered portion of the bearing and the hub base, the hub base is directed from the periphery to the center side. A force to act is applied, whereby the center of the bearing and the center of rotation of the rotor portion including the rotating shaft and the hub are made to coincide with each other, and radial runout of the rotor portion is regulated. Further, it is not necessary to provide the thrust receiver as a separate member, and the number of parts can be reduced.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing another embodiment of the bearing device according to the present invention.

FIG. 3 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 4 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 5 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 6 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 7 is a perspective view showing a sliding member in the embodiment.

FIG. 8 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 9 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 10 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 11 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 12 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 13 is a perspective view showing a sliding member in the embodiment.

FIG. 14 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 15 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 16 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 17 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 18 is a sectional view showing still another embodiment of the bearing device according to the present invention.

FIG. 19 is a sectional view showing an example of a motor using the bearing device according to the present invention.

FIG. 20 is a sectional view showing an example of a motor using a conventional bearing device.

[Explanation of symbols]

 2 Housing 3 Bearing 5 Rotating shaft 12 Tapered portion 13 Tapered portion 14 Rotating ball 20 Sliding means 23 Sliding means 24 Sliding means 25 Sliding means 26 Sliding means 27 Coating

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[Procedure amendment]

[Submission date] June 11, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 4

[Correction method] Change

[Correction content]

Claims (4)

[Claims] 1. A bearing device for rotatably supporting a rotating shaft fixed to a rotor part by a bearing held in a housing, wherein a taper part is provided on at least one side of a facing part of the bearing and the rotor part. The bearing device is characterized in that the tapered portion receives a force in the thrust direction of the rotary shaft and restricts the runout of the rotary shaft in the radial direction. 2. The bearing device according to claim 1, wherein a rotating ball that relatively rotates the bearing and the rotor portion is interposed between the facing portions of the bearing and the rotor portion. 3. The bearing device according to claim 1, wherein a sliding means for sliding the bearing and the rotor portion is interposed between the facing portions of the bearing and the rotor portion. 4. The bearing device according to claim 2, wherein the sliding means has a sliding surface coated with a low friction coefficient.