JP2007177799A - Pivot bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly roll rolling elements (balls) even if the voltage of a voice coil motor is very low. <P>SOLUTION: In this pivot bearing device used for the swing arm support part of a hard disk drive, a cage which has been used to retain the rolling elements 5 at equal intervals is abolished. Since the cage obstructing the operation of the rolling elements when the rolling elements 5 roll is absent, the rolling elements 5 can be smoothly rolled even if the voltage of the voice coil motor is very low. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pivot bearing device used for a swing arm support portion of a hard disk drive device.

  2. Description of the Related Art In a pivot bearing device used for a swing arm support portion of a hard disk drive device, a cage is used that holds a plurality of rolling elements arranged in an freely spaced manner between an inner ring and an outer ring at equal intervals.

  FIG. 3 is a cross-sectional view of a conventional pivot bearing device. A double row rolling bearing 2 is mounted on the pivot 1. In each rolling bearing 2, a plurality of rolling elements 5 are interposed between a raceway surface 3a of the outer ring 3 and a raceway surface 4a of the inner ring 4 so as to be freely rollable. On the outer side of the rolling bearing 2, a seal member 6 for sealing a lubricant such as oil is mounted. In addition, in the conventional example, a cage 7 for holding the plurality of rolling elements 5 at equal intervals is interposed.

  However, in the conventional example, when the cage and the rolling elements (balls) that hold the rolling elements at equal intervals roll, the rolling elements are caused by friction between the rolling elements or collision between the rolling elements and the cage. In particular, it becomes an obstacle when operating in a minute angle range, and there is a problem that the rolling element does not roll smoothly.

  In particular, the control angle of the swing arm has become smaller due to the higher recording density of the hard disk drive device, and the voltage applied to the voice coil motor to operate the swing arm in order to reduce power consumption. Due to the progress of reduction, a smooth operation response in a minute angle range of a bearing device, particularly a rolling element is further demanded.

  The present invention has been made in view of the circumstances as described above, and provides a pivot bearing device capable of smoothly rolling a rolling element (ball) even with a small voltage of a voice coil motor. With the goal.

In order to achieve the above object, a pivot bearing device according to the present invention is a pivot bearing device of a swing arm support portion of a hard disk drive device.
There is no cage that holds a plurality of rolling elements arranged in an freely spaced manner between the inner ring and the outer ring at equal intervals.

  Preferably, the hard disk drive device has a thickness of 5 mm or less, and is used for a swing arm support portion of the hard disk drive device.

  Preferably, the lubricant enclosed in the bearing is oil.

  According to the present invention, when the rolling element (ball) rolls, the rolling element (ball) smoothly rolls even with a small voltage of the voice coil motor because there is no cage that hinders the operation. Things will be possible. That is, when the rocking angle is small, the rolling bearing is preferably in the form of a full ball and having no contact between the rolling elements.

  Hereinafter, a pivot bearing device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a pivot bearing device according to an embodiment of the present invention. In a pivot bearing device used for a swing arm support portion of a hard disk drive device, a double row rolling bearing 2 is mounted on the pivot 1. In each rolling bearing 2, a plurality of rolling elements 5 are interposed between a raceway surface 3a of the outer ring 3 and a raceway surface 4a of the inner ring 4 so as to be freely rollable. On the outer side of the rolling bearing 2, a seal member 6 for sealing a lubricant such as oil is mounted. The rolling bearing 2 may be made of ceramics.

  In the present embodiment, the cage that has been conventionally used for the purpose of holding the rolling elements 5 at equal intervals is eliminated. When the rolling element 5 rolls, there is no cage that hinders its operation, so that the rolling element 5 can smoothly roll even with a minute voice coil motor voltage. That is, when the rocking angle is small, the rolling bearing 2 is preferably in the form of a full ball and having no contact between the rolling elements. .

  However, in order to keep the conventional pivot assembly equipment, the two rolling bearings alone incorporate a cage as in the prior art bearings. As a result, the rolling elements 5 are also advantageously arranged at equal intervals between the outer and inner rings 3 and 4.

  The cage is removed after the rolling bearing 2 is assembled as a pivot bearing device by press-fitting or bonding to the pivot 1 and the housing and preloaded.

  Although it is desirable to enclose the lubricant in a necessary amount at the time of assembling the bearing, it may be encapsulated after removing the cage after assembling the pivot bearing device.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

  FIG. 2 is a graph schematically showing the result of measuring the frequency displacement response by incorporating the pivot of the embodiment of the present invention and the conventional embodiment into a swing arm and a voice coil motor, and applying a voltage of each frequency to the VCM. .

  In the graph, as a conventional example, two experimental results of a cage in which rolling elements are arranged at equal intervals are made of plastic made of nylon or the like and iron made of stainless steel or the like.

  Of the conventional examples, because of its weight, the built-in iron cage that has the greatest friction and force on the rolling elements loses linear responsiveness from an early (high) frequency. Responsiveness disappears.

  In the example of the present invention, it was confirmed that linear response was maintained up to a lower frequency region.

  The present invention provides a thin hard disk drive (HDD) in which a swing arm is operated at a particularly fine angle at a lower voltage, that is, the linear response of the swing arm is required to a lower frequency range than before. It is valid. This is particularly effective for a hard disk drive (HDD) having a height of 5 mm or less.

  In the case of a hard disk drive (HDD) that requires such a fine response, a swing arm operation failure due to bearing loss leads to a decrease in data input / output speed. As the lubricant to be sealed in the bearing, fluorine oil, synthetic oil such as ester, cyclolopentane, PAO (poly α olefin) whose molecular weight distribution is controlled are effective. In the case of an oil-sealed bearing, there is no problem even if there is no cage required for enclosing grease in the bearing.

It is sectional drawing of the pivot bearing apparatus which concerns on embodiment of this invention. It is the graph which modeled the result of incorporating the pivot of the Example of this invention, and the conventional Example into a swing arm and a voice coil motor, and applying the voltage of each frequency to VCM, and measuring the frequency displacement response. It is sectional drawing of the pivot bearing apparatus which concerns on a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pivot shaft 2 Rolling bearing 3 Outer ring 3a Raceway surface 4 Inner ring 4a Raceway surface 5 Rolling element 6 Seal member 7 Cage

Claims (3)

In the pivot bearing device of the swing arm support part of the hard disk drive device,
A pivot bearing device characterized in that there is no cage for holding a plurality of rolling elements arranged in an freely spaced manner between an inner ring and an outer ring at equal intervals. The hard disk drive device has a thickness of 5 mm or less,
The pivot bearing device according to claim 1, wherein the pivot bearing device is used for a swing arm support portion of the hard disk drive device.   The pivot bearing device according to claim 1 or 2, wherein the lubricant enclosed in the bearing is oil.

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