JP2006275244A - Bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent abrasion in engaging surfaces due to creeping in a bearing unit which allows relative displacement of a rotary shaft 10 in the axial direction. <P>SOLUTION: An annular groove 7 is provided in an inner ring 1, in which the rotary shaft 10 is fitted freely to relatively displace in the axial direction, near both ends of the inner diameter surface of the inner ring 1, and O-rings 8 are installed in the annular groove 7, and grease A is sealed between two O-rings 8 installed in the inner diameter surface of the inner ring 1. With this structure, turning of the inner ring 1 is stopped by elastic fastening force of the O-rings 8, and the grease A sealed between the two O-rings 8 forms a lubricating oil film in the fitting surface between the inner ring 1 and the rotary shaft 10 to prevent abrasion in the fitting surface due to creeping. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bearing unit in which a rolling bearing is incorporated in a bearing housing, and more particularly to a bearing unit that supports a rotary shaft while allowing relative displacement in the axial direction.

  Bearing units incorporating rolling bearings in bearing housings are widely used for supporting rotating shafts such as rollers that wrap belt-like bodies such as conveyor belts and films because they can be easily mounted on the rotating shaft and are versatile. . In order to allow relative displacement in the axial direction of the rotary shaft due to thermal expansion or an error in the bearing interval during assembly, the bearing unit has a set screw for rotation prevention attached to the inner ring and the tip of the key bolt. Some are guided by a keyway provided on a rotating shaft (see, for example, Non-Patent Document 1). Also, there is a type in which a separate fixed ring is connected to the inner ring, and a set screw is attached to the fixed ring (see, for example, Patent Document 1).

“NTN Corporation Bearing Unit Catalog”, NTN Corporation, December 2004, p. 59 JP-A-9-250549

  In the bearing unit that allows the relative displacement of the rotating shaft in the axial direction as described above, the fit between the inner ring and the rotating shaft is set to be relatively loose. Therefore, there is a problem that wear occurs on the fitting surface of the inner ring and the rotating shaft. When wear of such a mating surface proceeds, the inner ring rattles, and there is a risk that the setscrew and key bolt for preventing rotation will break.

  Accordingly, an object of the present invention is to prevent wear of the fitting surface due to creep in a bearing unit that allows relative displacement in the axial direction of the rotating shaft.

  In order to solve the above-mentioned problems, the present invention incorporates a rolling bearing in which a plurality of rolling elements are disposed between an inner ring and an outer ring into a bearing box, and a rotating shaft fitted to the inner diameter surface of the inner ring In a bearing unit that supports relative displacement in the direction, an annular groove is provided near both ends of the inner diameter surface of the inner ring, O-rings are mounted, and grease is provided between the O-rings mounted on the inner diameter surfaces of these inner rings. Adopted a configuration that encloses.

  That is, an annular groove is provided near both ends of the inner ring surface of the inner ring, O-rings are mounted, and grease is sealed between the O-rings mounted on the inner surface of these inner rings, so that the inner ring can be elastically tightened by the O-ring In addition, a lubricating oil film is formed on the mating surface of the inner ring and the rotating shaft with the enclosed grease so that wear of the mating surface due to creep can be prevented.

  The bearing unit of the present invention is provided with an O-ring with annular grooves provided at both ends of the inner diameter surface of the inner ring to which the rotation shaft is fitted to allow relative displacement in the axial direction. By sealing the grease between the mounted O-rings, the inner ring is prevented from rotating by the elastic tightening force of the O-ring, and a lubricating oil film is formed on the mating surface of the inner ring and the rotating shaft with the sealed grease. Further, it is possible to prevent the fitting surface from being worn by creep.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, this bearing unit has a ball bearing in which a ball 3 as a plurality of rolling elements is disposed between an inner ring 1 and an outer ring 2 in a pillow type bearing box 4. The rotary shaft 10 fitted to the inner diameter surface of the inner ring 1 is supported while allowing relative displacement in the axial direction. Each ball 3 is held by a cage 5, and a bearing space between the inner ring 1 and the outer ring 2 is sealed with a seal 6.

  As shown in FIG. 3, annular grooves 7 are provided near both ends of the inner diameter surface of the inner ring 1, and O-rings 8 are attached to these annular grooves 7, and the inner ring 1 is connected to the rotary shaft 10 by its elastic tightening force. Is prevented from rotating. Grease A is enclosed between two O-rings 8 mounted on the inner diameter surface of the inner ring 1. Therefore, since the lubricating oil film of grease A is formed on the fitting surface between the inner ring 1 and the rotating shaft 10, wear of the fitting surface due to creep can be prevented.

  In the embodiment described above, the ball bearing is incorporated in the pillow-type bearing box, but the rolling bearing of the bearing unit according to the present invention is not limited to the ball bearing. Further, the bearing box is not limited to the pillow type, and can be applied to other types such as a flange type and a take-up type.

Front view showing an embodiment of a bearing unit Notched longitudinal side view of Fig. 1 Sectional drawing which expands and shows the principal part of FIG.

Explanation of symbols

A Grease 1 Inner ring 2 Outer ring 3 Ball 4 Bearing box 5 Cage 6 Seal 7 Annular groove 8 O-ring 10 Rotating shaft

Claims (1)

  A bearing unit in which a rolling bearing in which a plurality of rolling elements are disposed between an inner ring and an outer ring is incorporated in a bearing box, and a rotary shaft fitted to the inner diameter surface of the inner ring is supported while allowing relative displacement in the axial direction. The bearing unit is characterized in that an annular groove is provided near both ends of the inner surface of the inner ring and an O-ring is mounted, and grease is sealed between the O-rings mounted on the inner surface of these inner rings.

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