JP2006060905A - Fluid bearing motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a spindle motor whose wall thickness is reduced close to the ultimate, that is, a fluid bearing motor. <P>SOLUTION: The fluid bearing motor includes a bearing body 3 provided on a substrate 2 and a central shaft 1 whose lower end is bonded to the bearing body 3. The fluid bearing motor is constructed by: rotatably fitting the rotational cylindrical portion A of a hub 6 that rotates on the central shaft 1 onto the circumferential surface of the central shaft 1; forming a radial dynamic pressure generating portion on this fit portion; and placing at the upper part or the lower part of the rotational cylindrical portion A comprising a thrust plate 4 having a thrust directional dynamic pressure generating portion. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a small spindle motor having a fluid dynamic pressure bearing structure used for rotational driving of various OA devices, PDAs, HDDs, etc., and particularly a hydrodynamic bearing motor intended for an ultra-small motor of 1 inch or less. About.

  This type of small spindle motor has been required to be miniaturized with the advancement of the electronic apparatus with the recent miniaturization.

In addition to the shaft rotation system, a fluid dynamic bearing motor of a center shaft fixed system has been known (see Patent Document 1 and Patent Document 2).
JP 2001-327125 A JP 2003-153484 A

  By the way, the hydrodynamic bearing motor shown in Patent Document 1 is a center shaft fixing method in which a hub is rotated around a fixed center shaft, but the size in the left and right diameter directions can be made small. However, there is a problem that the height in the vertical direction, that is, the thickness cannot be reduced.

  Further, Patent Document 2 shows that the vertical height, that is, the thickness can be formed to be considerably thin, but there is a problem that it cannot be thinned.

  The present invention has been made paying attention to the above points, and an object of the present invention is to obtain a thin spindle motor, that is, a hydrodynamic bearing motor, in a state of being extremely small.

  The present invention can solve the above problems by including the following configuration.

  (1) A shaft support provided on the substrate and a center shaft having a lower end fixed to the shaft support are rotated, and a rotating cylinder portion of a hub that rotates around the center axis is rotated around the center shaft. It is freely inserted, and a radial dynamic pressure generating portion is formed in the insertion portion, and a thrust plate having a thrust dynamic pressure generating portion is disposed at the upper or lower portion of the rotating cylinder portion. A fluid dynamic bearing motor.

  (2) The upper thrust plate is engaged with and fixed to the upper portion of the central shaft to form an annular shape, and between the upper surface of the rotating cylinder portion of the hub and the hydrodynamic oil sealing plate that maintains the clearance space from the hub. The thrust plate is configured so that a dynamic pressure generating portion in the thrust direction can be formed between the upper and lower surfaces of the thrust plate and the lower surface of the dynamic pressure oil sealing plate and the upper surface of the rotating cylinder portion. The fluid dynamic bearing motor according to (1).

  (3) The lower thrust plate is formed in an annular shape at the lower portion of the rotating cylinder portion, and is opposed to the opposed surface of the lower portion of the shaft support and the annular dynamic pressure oil sealing plate provided between the shaft support and the central shaft. The hydrodynamic bearing motor according to (1), wherein the dynamic pressure generating portion in the thrust direction can be formed.

  (4) The hydrodynamic bearing motor as set forth in (1), wherein the rotary cylinder portion is configured such that a dynamic pressure generating portion in a radial direction can be formed by making an outer periphery thereof and an inner peripheral wall of the shaft support face each other. .

  According to the present invention, the thrust dynamic pressure generating portion acting in the thrust direction is made by one thrust plate, and at least two required thrust plates are made one, thereby reducing the wall thickness accordingly. As a result, the overall thickness can be gradually reduced, and the cost can be reduced by reducing the number of parts.

  In the following, two embodiments of the present invention will be described.

  FIG. 1 is a longitudinal sectional side view showing the entire configuration, and FIG. 2 is an enlarged sectional explanatory view of a main part.

  In this embodiment, a thrust plate is provided on the upper part.

  In each figure, 1 indicates a central axis (spindle), and a base end 1 a is fitted and fixed in a locking hole 3 a of a shaft support 3 fixed to the substrate 2. Specifically, a rising peripheral wall 2a is formed on the substrate 2, and a shaft support body 3 having a locking hole 3a formed in the rising peripheral wall 2a is protruded outwardly by a protruding flange 3b, and the upper surface of the rising peripheral wall 2a. And the peripheral wall 3c of the shaft support 3 is engaged with the inner peripheral surface of the rising peripheral wall 2a to be firmly fitted and fixed. Further, the base end 1a of the central shaft 1 is interposed via the step portion 1b. The diameter of the shaft support 3 is fixed in the locking hole 3 a of the shaft support 3 and is erected on the substrate 2.

  Reference numeral 4 denotes an annular thrust plate fitted and locked to a step portion 1c provided on the upper side of the central shaft 1, and the thrust plate 4 is fixed by a retaining ring 5 fitted to the central shaft 1 with a screw or the like. I am letting.

Reference numeral 6 denotes a hub provided with a rotating cylinder portion A that rotates at the dynamic pressure generating portion P ₁ around the central axis 1. An annular spacer 7 that can secure a thrust clearance of the thrust plate 4 is provided on the thrust plate 4. On the facing surface 6a facing the lower surface, the hydraulic pressure oil sealing plate 8 having an opposing surface 6b facing the upper surface of the thrust plate 4 is annularly disposed on the hub 6 while being disposed outside the thrust plate 4. The fixing piece 9 is fixed integrally.

  In the figure, reference numeral 10 is a rotor magnet provided on the hub 6, 11 is a stator, 12 is a disk fixed to the hub 6 with a stopper 13 such as rubber packing, and 14 is a screw formed at the top of the central shaft 1. At the joint portion, various plates can be fixed using screws (not shown).

  In the illustrated example, the rotor magnet 10 is an inner rotor type inside the stator 11, but the same can be applied to an outer rotor type formed in the opposite direction.

In the above-described configuration, the hub 6 generates a dynamic pressure in the radial direction at the dynamic pressure generating portion P ₁ between the central shaft 1 and the rotating cylinder portion A, and the opposite surface 6 a of the hub 6 and the lower surface of the thrust plate 4. In addition, dynamic pressure in the thrust direction is generated at the dynamic pressure generating portions P ₂ and P ₃ between the opposed surface 6 b on the upper surface of the thrust plate 4 and the dynamic pressure oil sealing plate 8. The hydrodynamic pressure generating portions P ₁ , P ₂ , and P ₃ are filled with dynamic pressure generating oil, and a herringbone groove, for example, for generating the dynamic pressure is recessed in at least one surface (see FIG. Not shown).

Because of the above configuration, the central shaft 1 that is erected and fixed to the substrate 2 via the shaft support 3 and the hub 6 of the rotating portion that constitutes the rotor are the dynamic pressure generating portion P ₁ with the central shaft _1. And the dynamic pressure generating portions P ₂ and P ₃ with the upper thrust plate 4 generate dynamic pressures in the radial direction and the thrust direction to support rotation, and substantially form other sliding portions. Therefore, the resistance load can be reduced, and high-speed rotation is possible and the rotation performance can be improved.

  In particular, since the thrust plate 4 is formed as a single piece, the overall thickness can be reduced.

  FIG. 3 is an overall longitudinal sectional side view illustrating another embodiment, and FIG. 4 is an enlarged cross-sectional explanatory view of a main part. In each case, the rotating portion is hatched. Accordingly, the center shaft 1 is also used as an upright support.

  This embodiment shows a case where a thrust plate is provided at the lower portion, and is substantially the same as that of the first embodiment. Therefore, the same and equivalent components are denoted by the same reference numerals, and detailed description thereof is omitted.

  The thrust plate 4A provided at the lower portion is fixed to the lower portion of the rotary cylinder portion A, and the lower facing surface of the thrust plate 4A is opposed to the facing surface of the dynamic pressure oil sealing plate 8A. The locking hole 4a of the oil sealing plate 8A is firmly engaged through a step portion 1b having a small diameter at the base end 1a of the central shaft 1.

Then, the inner peripheral wall 15a of the bearing member 15, which are opposed to the outer peripheral surface 16 of the rotating cylinder portion A of the hub 6 to form a dynamic pressure generating portion P ₁ in the radial direction.

Further, as described above the lower portion of the rotary cylinder portion A of the integral with the hub 6, the thrust plate 4A to form the dynamic pressure generating portion P ₂ and the surface facing the dynamic pressure oil sealing plate 8A is integrally fixed Te there, said the dynamic pressure generating portion P ₂ are allowed configured to generate a thrust direction dynamic pressure. Also, the dynamic pressure generating portion P ₃ is formed in the bearing member 15 facing the upper surface of the thrust plate 4A, it has a structure that also generate thrust direction dynamic pressure.

Accordingly, the dynamic pressure generating portions P ₁ , P ₂ , P ₃ in the radial direction and the thrust direction are filled with dynamic pressure oil as in the first embodiment, and a herringbone groove for generating dynamic pressure is formed. Of course.

  Reference numeral 17 denotes a cover plate screwed at the top of the central shaft 1.

Also in this embodiment, a hub that rotates about a central shaft 1, the dynamic pressure generating portion P ₁ and the thrust plate 4A and the lower dynamic pressure oil sealing plate 8A between the rotating cylindrical portion A and the bearing member 15 Since dynamic pressures in the radial direction and the thrust direction are generated at two locations of the dynamic pressure generating portions P ₂ and P ₃ , high-speed rotation can be achieved.

  In addition, since the thrust plate in the thrust direction is a single sheet, it is possible to reduce the thickness and make it ultra-small, especially with a small thickness.

  As described above, the two embodiments of the present invention have been described. Of the dynamic pressure generating portions in the radial direction and the thrust direction of the hub that supports and rotates the disk, the radial direction may be formed corresponding to the central axis. In addition, the thrust direction may be dealt with by providing a dynamic pressure generating portion on a thrust plate provided on either the upper side or the lower side. Furthermore, the hub itself can be variously configured in terms of structure, but the main point is that it does not matter if the dynamic pressure generating part acting on the thrust plate over the front surface or both front and back surfaces works. .

  Further, since the sleeve can be made unnecessary, the number of parts can be omitted, the cost can be reduced, and the size and size can be reduced.

Longitudinal side view showing the overall configuration Explanatory cross-sectional explanatory drawing of the main part Overall longitudinal sectional side view showing another embodiment Explanatory cross-sectional explanatory drawing of the main part

Explanation of symbols

1 Central axis (spindle)
1a proximal second substrate 4,4A thrust plate 6 hub 8,8A dynamic pressure oil sealing plate A rotating cylinder unit _{P 1,} P 2, _{P 3} dynamic pressure generating portion

Claims (4)

  A shaft support provided on the substrate and a center shaft having a lower end fixed to the shaft support are provided, and a rotating cylinder portion of a hub rotating around the center axis is rotatably inserted on the outer periphery of the center shaft. A radial dynamic pressure generating portion is formed in the insertion portion, and a thrust plate having a thrust dynamic pressure generating portion is disposed at the upper or lower portion of the rotating cylinder portion. Fluid bearing motor.   The upper thrust plate is engaged with and fixed to the upper portion of the central shaft and formed into an annular shape so that it can be sandwiched between the upper surface of the rotating cylinder portion of the hub and the dynamic pressure oil sealing plate that maintains the clearance space from the hub. Further, a dynamic pressure generating portion in the thrust direction can be formed between the upper and lower surfaces of the thrust plate, the lower surface of the dynamic pressure oil sealing plate, and the upper surface of the rotating cylinder portion. Item 2. The hydrodynamic bearing motor according to Item 1.   The lower thrust plate is formed in an annular shape at the lower portion of the rotating cylinder portion, and is opposed to the lower facing surface of the shaft support and the annular dynamic pressure oil sealing plate provided between the shaft support and the central shaft. 2. The hydrodynamic bearing motor according to claim 1, wherein the hydrodynamic pressure generating portion can be formed.   The hydrodynamic bearing motor according to claim 1, wherein the rotary cylinder portion is configured such that a radial dynamic pressure generating portion can be formed by making an outer periphery thereof and an inner peripheral wall of the shaft support face each other.

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