JPH0988984A - Sealing device of rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To check or control any outflow of fine grains to the outside of a bearing by installing an attraction means for these fine grains such as dust to be produced by rotation, in the inner part of the bearing with a noncontact type sealing member. SOLUTION: This sealing device is provided with a pair of shield plates 5 and an electrostatic attraction film 6 stuck to each inner surface side of these paired shield plates 5. The shield plates 5 are provided with each of fixed parts 5a curvedly formed on an outer circumferential part of a metallic ring thin plate, and this part is press-in fitted in a ringlike fixed groove 2a installed in an end inner circumference of the outer ring 2, thereby forming a labyrinth clearance S in space between the inner circumferential end and the circumference of an inner ring 1. The electrostatic attraction film 6 consists of a wafer- thin film material borne with static electricity, adsorbing fine grains such as minute dust in a micron unit floating in the air by dint of electrostatic force. Since the fine grains being contained in the out gas produced in the inner part of the bearing are adsorbed by this film 6, an inflow of the fine grains to the outside of the bearing is checked or controlled, and thus there is no pollution at the outside of the bearing.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a hard disk drive (HDD), a laser beam printer (LB), and the like.
P), an optical disk drive (ODD), and other information equipment, the present invention relates to a bearing seal device that rotatably supports a spindle shaft of a spindle motor.

[0002]

2. Description of the Related Art As an example, FIG. 2 shows a general configuration of a hard disk drive (HDD: guide roller system). In the disk spindle portion shown in the figure, the pair of bearings 11 play a role of rotatably supporting the spindle shaft 13 having the magnetic disk 12 mounted on the outer periphery with respect to the housing 14. A rotor 16 of a spindle motor is connected to the spindle shaft 13 via a casing 15, and a stator 17 of the spindle motor is fixed to the outer periphery of the housing 14 so as to face the rotor 16. When a current is applied to the spindle motor, the rotor 16 magnetically rotates with respect to the stator 17, whereby the spindle shaft 13 rotates and the magnetic disk 12 rotates.

By the way, a magnetic disk 12 which requires particularly cleanliness is adjacent to the periphery of the bearing 11, and the bearing 1
When the outgas generated from the grease inside the exhaust gas 1 is discharged from the bearing 11, fine particles (small suspended matter such as dust) contained in the outgas may adhere to the magnetic disk 12 and cause a head crash, malfunction, or the like. . Therefore, the seal device 18 is attached to the end portion side of the bearing 11 which is the outgas outflow path to prevent the outgas from flowing out of the bearing 11.

As the seal device 18, non-contact type devices such as magnetic fluid seals and labyrinth seals (rubber seals) are currently used in consideration of low torque (contact type seals increase the bearing torque). However, due to the recent trend toward cost reduction of information equipment, it is becoming more and more common to avoid the use of expensive magnetic fluid seals and use inexpensive labyrinth seals.

[0005]

When a labyrinth seal is used as the sealing device 18, deterioration of the sealing property is inevitable as compared with the case where a magnetic fluid seal or a contact type seal is used. Therefore, at present, a means for suppressing generation of outgas in the bearing is adopted by enclosing a so-called low outgas grease such as sodium-mineral oil grease, lithium-synthetic oil grease, and urea-synthetic oil grease. There are many.

However, depending on the type of the low outgas grease to be filled, there is a concern that the acoustic value and the torque value of the bearing may be adversely affected, and the development of the low outgas grease requires a great deal of labor and cost and is costly. It leads to up.

As a solution to such a problem, the applicant of the present invention arranges a thin floating ring seal in a floating manner on the inner side of the bearing than the labyrinth seal so that the outgas flow from the inside of the bearing to the labyrinth clearance is floating ring seal. Japanese Patent Application No. 6-28684 proposes a means capable of obtaining a sealing effect that is as high as when a contact type seal is used by blocking or suppressing it by means of an increase in the number of assembly steps. At present, it is unfavorable from the viewpoint of actual manufacturing process control because it is troublesome to control the seal dimensions.

Therefore, according to the present invention, in view of the fact that the adhesion of fine particles such as dust contained in the outgas is a factor of head crash, malfunction of the magnetic disk, etc., the fine particles such as dust generated inside the bearing are transferred to the outside of the bearing. Another object of the present invention is to provide a sealing device which prevents or suppresses the outflow of the resin and has improved assembly workability and dimensional control.

[0009]

The sealing device of the present invention comprises:
Inside the rolling bearing, which is composed of the inner ring and the outer ring, rolling elements that are equally arranged via a cage between them, and non-contact type seal members that are attached to both ends of the inner and outer rings, It is provided with an adsorbing means for adsorbing fine particles such as dust generated by the rotation.

Further, in the above construction, an electrostatic adsorption film made of an extremely thin electrostatically charged film material is used as the adsorption means.

Since the fine particles such as dust generated inside the bearing are adsorbed by the adsorption means, it is possible to prevent or suppress the outflow of the fine particles such as dust generated inside the bearing to the outside of the bearing.

Also, by using an electrostatic adsorption film made of an electrostatically charged ultra-thin film material as the adsorption means, it can be affixed to a seal member or the like, which adversely affects the acoustic value and torque value of the bearing. Moreover, since it does not need to be applied and only needs to be attached to a seal member or the like, the number of assembling steps can be slightly increased.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. The embodiment shown in FIG. 1 is an application of the present invention to a sealing device for a sealed ball bearing. This sealed ball bearing is, for example, a hard disk drive (HDD).
In the disk spindle part of the above, it is for rotatably supporting the spindle shaft (see FIG. 2). It is composed of a cage 4 held at intervals, a pair of shield plates 5 fixed to the inner circumference of the end portion of the outer ring 2, and an electrostatic adsorption film 6 attached to the inner surface side of the shield plate 5.

The shield plate 5 is provided with a curved fixed portion 5a on the outer peripheral portion of an annular thin plate made of metal, and the fixed portion 5a is provided.
Is fixed to the inner periphery of the end of the outer ring 2 by press-fitting into the annular fixing groove 2a provided on the inner periphery of the end of the outer ring 2,
A labyrinth clearance S between the inner peripheral edge and the outer periphery of the inner ring 1
To form

The electrostatic adsorption film 6 is made of an electrostatically charged ultra-thin film material, and adsorbs fine particles such as small dust particles of micron size floating in the air by electrostatic force.

As described above, since the electrostatic adsorption film 6 attached to the inner surface of the shield plate 5 adsorbs the fine particles contained in the outgas generated inside the bearing, the fine particles contained in the outgas to the outside of the bearing. Outflow is prevented or suppressed, and there is no harmful effect of polluting the outside of the bearing. Moreover, since the electrostatic adsorption film 6 is adhered to the inner surface of the shield plate 5, it does not adversely affect the acoustic value and torque value of the bearing, and the electrostatic adsorption film 6 is attached to the shield plate 5. Since it only has to be attached to the inner side surface, the number of assembly steps is slightly increased. Further, the cost can be reduced by changing the current labyrinth seal to the shield plate 5.

Although the above description applies the present invention to a sealing device for hermetically sealed ball bearings, the present invention is not limited to this and can be applied to other sealing devices for rolling bearings in general. Further, although the electrostatic adsorption film 6 is attached to the shield plate 5, it can be attached to the existing labyrinth seal and, in the case of a solid lubrication rolling bearing that does not use grease, electrostatic It is also possible to attach the mold adsorption film 6 to the inner / outer rings 1 and 2 and the cage 4, and in this case also, the same effect as the above is obtained.

[0018]

As described above, according to the present invention,
Since the adsorption means for adsorbing fine particles such as dust is provided inside the bearing, outflow of fine particles such as dust to the outside of the bearing is prevented or suppressed, and contamination of the outside of the bearing can be prevented.

Further, by using an electrostatic adsorption film made of an electrostatically charged ultra-thin film material as the adsorption means, the above-mentioned effect can be surely exhibited, and at the same time, it can be attached to a seal member or the like. The acoustic value and torque value of the bearing are not adversely affected, and moreover, since it is sufficient that the bearing member is attached to the seal member or the like, the number of assembling steps can be slightly increased.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a sealed ball bearing equipped with a sealing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a general configuration of a hard disk drive (HDD: guide roller system).

[Explanation of symbols]

 1 Inner ring 2 Outer ring 2a Fixed groove 5 Shield plate 5a Fixed part 6 Electrostatic adsorption film

Claims (2)

[Claims] 1. A rolling bearing comprising an inner ring and an outer ring, rolling elements equidistantly arranged between them through a cage, and non-contact type seal members mounted at both ends of the inner and outer rings. A sealing device for a rolling bearing, comprising an adsorbing means for adsorbing fine particles such as dust generated as the bearing rotates. 2. The seal device for a rolling bearing according to claim 1, wherein an electrostatic adsorption film made of an ultra-thin electrostatically charged film material is used as the adsorption means.