JP2005337319A - Super-thin bearing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a super-thin bearing structure which is formed into a slide-contact state, simplifies structure, and generates a pre-load by using the optimum magnetic attraction force of a magnet. <P>SOLUTION: A tubular sleeve 3 is rotatably inserted along the outer peripheral surface of a columnar shaft 1 erected fixedly to a base 2 and brought into a slide-contact state. A gap in a radial direction is reduced to a minimum and an annular magnet 5 effecting magnetic attraction between itself and the base 2 is provided. A thrust ball 7 is fixed in a circular hole 6 at the upper central position of the annular housing 4 having at a central part the sleeve 3 and supported on the upper surface of the shaft 1. The super-thin bearing structure is characterized such that a thrust gap can be eliminated by pressurizing in a thrust direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ultra-thin bearing structure that is required to be small and thin for use as a movable piece bearing provided with a magnetic head such as a VCM (voice coil motor) used in an HDD or the like.

Conventionally, this type of bearing structure generally uses a ball bearing exclusively (see, for example, Patent Documents 1 and 2 and Patent Document 3).
Japanese Patent No. 3243121 JP 2001-43658 A Japanese Patent Laid-Open No. 9-324818

  In such a ball bearing structure, in order to maintain high accuracy, it is impossible to make it ultra-small in structure, and the outer diameter is limited to about 5 mm to 6 mm at most. The following miniaturization was not feasible at all.

  In response to such a problem, the present applicant has proposed a ball bearing-less bearing structure capable of being ultra-compact in Japanese Patent Application Laid-Open No. 2003-120663 and Japanese Patent Application No. 2003-3201.

  This invention was also made under the same problem as the previous patent application. In the conventional ball bearing structure, the preload cannot be reduced, and there is a limit to reducing the axial loss. In particular, the thrust gap is eliminated, the positional accuracy of the housing that rotates relative to the center axis (shaft) is improved, and an ultra-thin bearing structure that is excellent in durability against vibration and impact is provided. Objective.

  This invention can solve the above-mentioned problems by having the following configuration.

  (1) A tubular sleeve is rotatably inserted along the outer peripheral surface of a cylindrical shaft fixedly erected on the base to make a sliding contact, thereby minimizing a radial gap and between the base and the base. A thrust ball is fixed in a circular hole at the center of the upper portion of the annular housing having an annular magnet for magnetic attraction and having the sleeve at the center, and is supported on the upper surface of the shaft, and a preload is applied in the thrust direction. An ultra-thin bearing structure characterized by being able to eliminate a thrust gap.

  (2) The ultra-thin bearing structure according to (1), wherein the shaft is formed as a sliding bearing portion protruding outward at the same diameter at the upper and lower portions.

  (3) The magnet is provided on the outer periphery of the sleeve at the lowermost part of the housing, and the thrust ball is pressed against the shaft by directly acting the magnetic attraction force through the distance from the base where the shaft is fixed upright. The ultra-thin bearing structure according to the above (1), characterized in that it can be eliminated.

  (4) The ultra-thin bearing structure according to (1), wherein one of the shaft and the housing is fixed and the other is rotatable.

  According to the present invention, in the radial direction with respect to the shaft, since the sleeve fixed to the housing is inserted into the shaft and no bearing is interposed, the gap between the sleeve and the shaft can be minimized, and the thrust can be reduced. The direction is such that the thrust ball fixed to the housing is brought into point contact with the upper surface of the shaft, and the base is effectively brought about by the optimum magnetic attraction force acting between the magnet fixed to the housing and the base directly through the interval. Since it can be pressed to the side, the entire structure can be formed thin.

  Furthermore, in the thrust direction, the housing can be pressed against the base side by the magnetic attraction force of the magnet, so that the shaft can be given an optimal preload, so the axial gap can be reduced by eliminating the thrust gap and this preload can be applied. As a result, the positional accuracy of the housing is improved, and the housing can be resistant to vibration, impact, and the like.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  This embodiment shows a case where the shaft is non-rotated by being fixedly erected on the desired fixed side.

  In the figure, reference numeral 1 denotes a cylindrical shaft fixedly erected on a base 2 made of a desired magnetic material, and upper and lower portions are provided with sliding bearing portions 1a and 1b having the same diameter and projecting outward. . The entire outer peripheral surface of the shaft 1 can also be used as a sliding bearing portion. Reference numeral 3 denotes a tubular sleeve that is rotatably inserted into the outer periphery of the shaft 1, and 4 is an annular housing that includes the tubular sleeve 3 at the center inner periphery and that is provided with an annular magnet 5 at the bottom. A circular hole 6 is opened at the upper center of the housing 4, and a spherical thrust ball 7 is press-fitted and fixed in the circular hole 6.

  The housing 4 is supported by a point contact at the central point P on the upper surface 1A of the shaft 1 with the spherical lower portion of the thrust ball 7 disposed at the upper center, and the sleeve 3 is slipped on the outer periphery of the shaft 1. The magnet 5 provided in the housing 4 is arranged and combined as a bearing part, and is optimal for the shaft 1 by eliminating the gap by the effective action of the magnetic attraction force with respect to the base 2 formed through a minute interval. Preload is applied below the value, not only can shaft loss be remarkably reduced, but the overall structure of the bearing can be made thin, and the positional accuracy of the housing is improved, and it is also durable against vibration and shock. A bearing can be provided.

  In the figure, reference numeral 8 denotes a screw portion for attaching another member provided on the housing 4, and 9 denotes a cover, which is fixed to the lower base 2 with a stop structure (not shown) such as a shaft.

  Next, the assembly process of the ultra-thin bearing based on the above embodiment will be briefly described.

  First, the shaft 1 is positioned on the base 2 using a jig and fixed by bonding or the like.

  Next, a thrust ball 7 is press-fitted into and integrated with a circular hole 6 on the upper surface of the housing 4 that has been formed in advance and positioned, and the magnet 5 is fixed to the lower portion of the housing 4 by bonding or the like, and further a sleeve at the center. 3 is similarly fixed by adhesion or the like.

  Next, oil (not shown) is injected into the upper portion of the shaft 1, and the housing 4 is inserted into the shaft 1.

  Finally, the cover 9 is shielded and fixed to the base 2 with a fastening structure such as a screw, so that the required ultra-thin bearing structure can be obtained.

  In the above embodiment, only a general and common configuration is described. However, in the case of a VCM bearing of an HDD, for example, the housing 4 is fixed using the screw portion 8 of the housing 4 as a rotating portion. The arm (not shown) can be rotated using the thin bearing structure as it is in accordance with the linear operation of the VCM.

In the longitudinal cross-sectional view of the ultra-thin bearing structure showing one embodiment of the present invention, the structure is exaggerated and exaggerated for clarity and clarity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 1a, 1b Sliding bearing part 2 Base 3 Sleeve 4 Housing 5 Magnet 6 Circular hole 7 Thrust ball 8 Screw part 9 Cover

Claims (4)

  A tubular sleeve is rotatably inserted along the outer peripheral surface of a cylindrical shaft fixedly erected on the base to make a sliding contact, thereby minimizing a radial gap and magnetically attracting between the base and the base. A thrust ball is fixed in a circular hole at the upper center position of an annular housing having an annular magnet and having the sleeve at the center, and is supported by the upper surface of the shaft, and a preload is applied in the thrust direction to form a thrust gap. An ultra-thin bearing structure characterized in that it can be eliminated.   2. The ultra-thin bearing structure according to claim 1, wherein the shaft is formed as a sliding bearing portion projecting outwardly with the same diameter at the upper and lower portions.   The magnet is provided on the outer circumference of the sleeve at the bottom of the housing, and the thrust ball is pressed against the shaft by directly acting the magnetic attraction force through the distance from the base where the shaft is fixed upright, and preload is applied to eliminate the thrust gap. The ultra-thin bearing structure according to claim 1, wherein the structure is made possible.   The ultra-thin bearing structure according to claim 1, wherein one of the shaft and the housing is fixed and the other is rotatable.

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