JPH10176719A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply the sufficient amount of lubricants to a contact part even during fine swinging so as to prevent fretting damage to the contact part by performing an oil repelling treatment for the surface of the rolling element of a rolling bearing and the track of an outer member or an inner member. SOLUTION: A ball bearing suitably used for a bearing device or the like for a swing arm used for a magnetic disk device includes the outer ring (track ring) of an outer member, the inner ring (track ring) of an inner member and a ball 1 held by a holder so as to be rolled between the track 2 of the outer ring and the track 2 of the inner ring. In this case, oil repelling treated layers 14 are formed on the surface of the ball 1 of the ball bearing, the tracks 2, the inner peripheral surface of the outer ring in both sides of the axial direction of the track 2 and the outer peripheral surface of the inner ring in both sides of the axial direction of the track 2 by oil repelling treatments. Thus, oil or oil 15 oozed out of grease is held in the bearing space 17 or the like of a contact part 3 between the ball 1 and the track 2 by self surface tension, a sufficient amount of oil is always supplied to an oil film in the bearing space 17 and thereby the phenomenon of used-up lubricants is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing, and more particularly to a disk drive device such as a magnetic disk device, a magneto-optical disk device, and an optical disk device, a VTR, a DAT,
The present invention relates to a rolling bearing used for information, video, audio equipment, precision equipment, and the like such as a laser beam printer.

[0002]

2. Description of the Related Art As a conventional rolling bearing, for example, there is a rolling bearing used for a swing arm bearing device for a magnetic disk device. This swing arm bearing device is used by applying preload to two ball bearings filled with grease, and a contact portion 3 between the ball 1 and the raceway 2 of the ball bearing is formed in a bearing clearance as shown in FIG. Are in contact through the oil film.

[0003]

Recently, there has been a demand for higher density magnetic disk drives. As a result, the width of recording signals on disks is becoming increasingly narrower, and swing arms equipped with heads for recording and reproducing signals are required to have faster access to target tracks and higher precision positioning performance. ing. Accordingly, it is required that the ball bearing that supports the swing arm has low torque and no torque fluctuation such as a torque spike (rapid torque fluctuation) in order to satisfy high-speed control and high accuracy.
Also, the rolling bearings used there will be increasingly used for high speed micro-swinging.

In a conventional ball bearing for a swing arm, if the amount of grease is extremely reduced in order to reduce torque, as shown in FIG. There is a problem that the grease 4 runs out from the contact portion 3 with the ball 1 and the grease 4 is depleted at the contact portion, and the track 2 of the ball bearing is easily damaged by fretting due to swinging. Therefore, an object of the present invention is to provide a swing arm bearing that has excellent fretting durability, low torque, and little torque fluctuation.

[0005]

In order to solve the above-mentioned problems, a rolling bearing according to the present invention is provided with an oil-repellent treatment on at least one of a surface of a rolling element, a track of an outer member and a track of an inner member. .

In the present invention, rolling elements (balls, rollers, etc.)
Since at least one surface of the inner surface of the bearing, such as the surface, the raceway of the outer member and the raceway of the inner member, has been subjected to oil repellent treatment, when oil or grease is used as a lubricant in the bearing, the oil or grease oozes out. The lubricant such as oil is held in the bearing clearance at the contact portion between the rolling element and the track and the clearance between the ball and the track adjacent to the bearing clearance by the action of its own surface tension. Therefore, the contact portion is always covered with a lubricant such as oil, and a sufficient amount of lubricant is supplied to the contact portion even during a minute swing, so that the lubricant in the contact portion does not run out, and the contact portion is fretting. Damage can be prevented. When oil is used as the lubricant, a bearing with low torque and little torque fluctuation can be obtained. Even if oil is used as a lubricant, the oil is repelled inside the bearing, so the oil is applied by the surface tension of the oil itself to the above-mentioned bearing clearance and the clearance between the ball and the track adjacent to the bearing clearance. It is retained and does not flow out of the bearing.

[0007]

DETAILED DESCRIPTION OF THE INVENTION At least one of the surface of the rolling element, the trajectory of the outer member and the trajectory of the inner member is subjected to an oil-repellent treatment in which an oil-repellent having an oil-repelling property is applied. . In the oil repellent treatment, the rolling element, the outer member, the inner member or the rolling bearing is immersed in a solvent in which an oil repellent is diluted in advance, and then the rolling element, the outer member,
It is preferable to dry the solvent adhered to the inner member or the rolling bearing. The rolling bearing,
It can be used for a bearing device for a swing arm of a magnetic disk device, a magneto-optical disk device, or an optical disk device. The rolling element is preferably spherical or roller-shaped. The oil repellent treatment may be performed using a fluorine-based modified film. The oil repellent is preferably a silicone oil or a fluorine-based water repellent. In this case, it is preferable that the contact angle between the oil-repellent layer subjected to the oil-repellent treatment and the lubricant is not less than 2 ° and less than 90 ° in order to make the lubricant in the bearing clearance sufficient. When the contact angle is smaller than 2 °, the lubricant spreads through the oil-repellent layer to reduce the amount of lubricant in the bearing clearance, and when the contact angle is 90 ° or more, it becomes difficult for the lubricant to enter the bearing clearance. . It is preferable that the contact angle is 10 ° or more in order to make the lubricant in the bearing clearance more sufficient. Thus, the contact angle is 2
It is preferable to select a lubricant and an oil repellent at an angle of at least 10 °, more preferably at least 10 ° but less than 90 °.

[0008]

2A and 2B are sectional views of a ball bearing according to the present invention. FIG. 2A shows a ball bearing 8 using a seal 7 comprising an elastic body 5 and a reinforcing plate 6 (for example, a fully-open flat type 6-51555).
2b shows a ball bearing 10 using a metal shield plate 9. Ball bearing 8,
Reference numeral 10 denotes an outer ring 11 (orbital ring) of an outer member, an inner ring 12 (orbital ring) of an inner member, and a retainer 13 held by the retainer 13 so as to perform rolling motion between the orbit 2 of the outer ring 11 and the orbit 2 of the inner ring 12. Ball 1 that has been cut. When the outer ring 11 is used for rotation, the ball bearing 8 using the seal 7 in which the elastic body 5 is attached in contact with the outer ring 11 is preferable for preventing oil from scattering outside the bearing due to centrifugal force.

FIG. 1 is an enlarged view of a contact portion between a ball 1 and a raceway 2 of an outer ring 11 of the ball bearing with a retainer of the present invention shown in FIGS. 2a and 2b. It is also an enlarged view of a contact portion with the contact. Oil or grease is used as a lubricant in the bearing. The surface of the ball 1 of the ball bearing, the track 2,
Oil-repellent layers 14 are formed on the inner peripheral surfaces of the outer races 11 on both sides in the axial direction of the track 2 and on the outer peripheral surfaces of the inner races 12 on both sides in the axial direction of the race 2, respectively. The oil 15 oozing out of the oil or the grease causes the bearing clearance of the contact portion 3 between the ball 1 and the track 2 due to its own surface tension, the clearance between the ball 1 and the track 2 circumferentially adjacent to the bearing clearance, and the bearing. The ball is held in a gap 17 between the ball 1 and the bearing rings 11 and 12 which are axially adjacent to each other. As a result, the oil 15 is always held in the bearing clearance and the portion adjacent to the bearing clearance, and a sufficient oil is constantly supplied to the oil film in the bearing clearance. It is preferable to use oil as the lubricant, because the oil improves the long-term retention at the contact portion between the ball 1 and the track 2 and has a small torque fluctuation. When a synthetic oil or a mineral oil is used as a lubricant, it is preferable to perform an oil-repellent treatment using a fluorine-based modified film or the like. When a fluorine oil is used as the lubricant, it is preferable to use a silicone oil or a fluorine-based water / oil repellent (for example, Knox Guard ST-420 manufactured by Nippon Mektron Co., Ltd.) or the like as the oil repellent.

[0010] As a method of the oil repellent treatment, each part of the rolling bearing alone (outer ring 1) in a solvent in which an oil repellent is diluted in advance.
1, the inner ring 12, the ball 1, the cage 13, etc.) or the rolling bearings, and then the solvent is dried. In particular, in the case of a rolling bearing, there is no need to perform an oil-repellent treatment for each part, and the rolling bearing can be immersed so that the processing cost is advantageously reduced. The rolling bearing in which the rolling element and the retainer are disposed between the outer ring and the inner ring may be immersed in a solvent diluted with an oil repellent, and then the solvent of the rolling bearing may be dried. Then, a seal may be attached to the rolling bearing. The rolling bearing provided with the rolling elements between the outer ring and the inner ring may be immersed in a solvent diluted with an oil repellent, and then the solvent of the rolling bearing may be dried.

In some cases, an oil repellent treatment is applied to the outer ring end face and the inner ring end face in order to prevent oil scattering. However, in order to apply the oil repellent only to the end face of the bearing ring, a solvent diluted with the oil repellent is used. The operation of applying to the end face of the bearing ring by attaching it to a cotton swab or the like is required, which increases the cost. In contrast, in the present invention, since the rolling bearing or each component alone can be treated simply by immersing it in a solvent diluted with an oil repellent, the processing cost is reduced.

In the embodiment of the present invention, at least one of the track of the outer member, the track of the inner member, the rolling element and the retainer is coated with an oil repellent having a property of repelling lubricating oil.
By applying an oil repellent to the raceway of the outer member, the raceway of the inner member, and the rolling element, a bearing clearance between the raceway of the rolling element and the outer member, a bearing clearance between the raceway of the rolling element and the raceway of the inner member, and Lubricants are preferably retained in the clearance between the ball and the track adjacent to the bearing clearance. Further, it is preferable to apply an oil repellent to the rolling elements and the retainer, since the lubricant is held between the rolling elements and the retainers. If an oil repellent is applied to the rolling element and the track (the track of the inner member, the track of the outer member), the oil between the rolling element and the track is repelled by the oil repellent, and the surface tension causes the oil and the track to move between the rolling element and the track. Gather in between. When the outer ring is displaced in the circumferential direction with respect to the inner ring, the rolling elements are displaced in the circumferential direction with respect to the track, but the oil between the rolling elements and the track is repelled by an oil repellent and displaced, and the rolling elements and the track are displaced. And always stay in between. The present invention can be applied to a roller bearing with a cage, a full ball bearing, and a full roller bearing. Further, the track 2 may be provided on the inner peripheral surface of the housing using the outer member as the housing, and the track 2 may be provided on the outer peripheral surface of the shaft with the inner member as the axis.
May be provided. Further, the track 2 may be a single row or a double row.

[0013]

According to the present invention, at least one of the rolling element surface, the outer member track and the inner member track is coated with an oil repellent. It is held in the clearance between the rolling element and the track by the action of surface tension. Therefore, the bearing clearance is always covered with a lubricant such as oil, and a sufficient amount of lubricant is supplied to the bearing clearance even during a minute swing, and the lubricant at the contact portion between the rolling element and the raceway is not depleted. And fretting damage of the contact portion can be prevented. Further, when oil is used as a lubricant, a rolling bearing having a low torque and a small torque fluctuation can be obtained. Even if oil is used as a lubricant, the oil is repelled inside the rolling bearing, so that the oil is held in the above-mentioned clearance and does not flow out of the bearing.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a contact portion between a ball and a track of a ball bearing according to an embodiment of the present invention.

FIG. 2a is a sectional view of a ball bearing according to an embodiment of the present invention.

FIG. 2b is a sectional view of the ball bearing according to the embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a contact portion between a ball and a track of a conventional ball bearing.

[Explanation of symbols]

 Reference Signs List 1 ball 2 raceway 3 contact portion 4 grease 5 elastic body 6 reinforcing plate 7 seal 8 ball bearing 9 metal shield plate 10 ball bearing 11 outer ring 12 inner ring 13 retainer 14 oil repellent treatment layer 15 oil 17 clearance

Claims (1)

[Claims] 1. A rolling bearing having a rolling element that performs rolling motion between a track of an outer member and a track of an inner member, wherein at least one of a surface of the rolling element, a track of the outer member, and a track of the inner member. A rolling bearing characterized in that oil repellent treatment is applied to each of them.