JP2013242024A - Thrust cylindrical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, during using a thrust cylindrical roller bearing, a difference due to a thrust load occurs in elastic deformation between an inner ring and an outer ring because there is a big difference between the backup width of the inner ring and the backup width of the outer ring in many cases, to produce a non-uniform bearing clearance, thus locally increasing a contact surface pressure between a roller and a raceway surface to easily cause a trouble such as an edge load or separation.SOLUTION: A bearing ring having a greater backup width, out of two bearing rings, has a protruded part on the end face contacting a housing so that an inner ring and an outer ring are the same in backup width. Thus, a thrust load is applied to the inner ring and the outer ring to be almost equal in elastic deformation to prevent a bearing clearance from being non-uniform in the radial direction.

Description

  The present invention relates to a thrust cylindrical roller bearing.

  In various industrial machines such as automobile transmissions and extrusion devices, thrust cylindrical roller bearings composed of bearing rings, cages and cylindrical rollers are used to support axial loads (hereinafter referred to as thrust loads). Generally, a thrust cylindrical roller bearing includes a roller with a cage that is incorporated in a cage so that the cylindrical roller is not separated, and a set of inner and outer rings. In these one set of race rings, the inner ring is attached to the shaft side and the outer ring is attached to the housing side (see FIG. 1).

  As the thrust cylindrical roller bearing, a bearing having one or two or more roller rows in the radial direction depending on the magnitude of the thrust load is used. The reason for using multiple rows of rollers is to reduce the differential slip between the rollers and the raceway surface, which is caused by the difference in circumferential length between the inner and outer diameter sides of the raceway surface by shortening the roller length. It is because it can do.

  In general, a thrust cylindrical roller bearing is used under a condition where a large thrust load is applied. During operation, the clearance of the roller portion is reduced and the race is easily elastically deformed. The state of deformation is influenced by the size of a hollow circular area (hereinafter referred to as “backup surface”) that serves as an axial contact surface between the inner ring and the shaft or between the outer ring and the housing.

  Normally, the shaft to which the inner ring of the bearing is attached is provided with a step for backup over the entire radial length of the inner ring so that the inner ring does not deform, even though a radial step for securing and positioning the inner ring is provided. It is rare to provide On the other hand, since the housing to which the outer ring is attached is originally a box shape, it is not so difficult to provide a contact surface between the outer ring and the housing over the entire length in the radial direction of the outer ring. In the case of thrust cylindrical roller bearings, when the engagement state of the mating surface is different between the inner ring side and the outer ring side, there is a difference in the amount of elastic deformation between the inner ring and outer ring due to the thrust load, and the distance and parallelism between the inner ring raceway surface and the outer ring raceway surface are appropriate. A state deviating from the value, so-called non-uniform bearing clearance occurs (see FIG. 4). As a result, the contact surface pressure between the roller and the raceway surface locally increases, and there is a problem that defects such as edge loading and peeling are likely to occur.

  To solve this problem, for example, the invention described in Patent Document 1 defines the shape of the mounting portion of the inner and outer rings. Specifically, the contact surface pressure on the backup surface is substantially equal between the inner ring and the outer ring. The shape of the mounting portion is set. This method is considered effective when the difference between the inner and outer diameters of the bearing ring is not so large as in the thrust ball bearing exemplified in Patent Document 1, but the inner and outer diameters of the bearing ring are different as in the thrust cylindrical roller bearing. When applied to a bearing with a large difference, the radial width (hereinafter referred to as “backup width”) of the hollow circular area as the backup surface is greatly different, resulting in a difference in the deformation of the raceway between the inner and outer rings. is there.

  The invention of Patent Document 2 prevents the contact surface pressure between the roller and the raceway from increasing locally even when the parallelism of the raceway surface is lost due to the load by applying asymmetric crowning to the roller end. However, applying crowning to the end of the roller is a cost-increasing factor, and if asymmetrical crowning is performed, the orientation of the roller must not be changed in the subsequent process. The problem that it becomes very difficult occurs.

JP 2007-285367 A JP-A-8-338481

  The present invention has been made in view of such a problem, and even when elastic deformation occurs in the inner and outer rings due to a thrust load, by making the respective deformation amounts substantially equal, it is possible to prevent occurrence of uneven bearing clearance, It is another object of the present invention to provide a thrust cylindrical roller bearing that does not cause problems such as edge load and separation on the raceway.

  When there is a difference in the backup width between the inner ring and the outer ring, a cylindrical axial protrusion between the backup surface and the bearing ring is possible for the bearing ring having a relatively large backup width among the backup widths of the inner and outer rings. And a radial contact length of a hollow circular contact surface between the projecting portion and the shaft or the housing is set to the same length as the backup width of the opposed raceway ring.

  By providing the above-mentioned protrusion, even when a large thrust load is applied, the inner ring and the outer ring show substantially the same deformation state, so that the parallelism of the raceway surface is difficult to lose and the bearing clearance becomes uneven. Suppress. As a result, it is possible to prevent a local increase in roller load, occurrence of an offset load, and wear and separation associated therewith.

It is sectional drawing which showed typically the state which provided the protrusion part in the end surface which faces the backup surface of an outer ring | wheel, and made the amount of elastic deformation of the inner and outer ring | wheels substantially equal. It is a perspective view of the outer ring | wheel which provided the protrusion part. It is sectional drawing which shows the state which incorporated the general thrust cylindrical roller bearing in the apparatus. FIG. 3 is a cross-sectional view schematically showing a state in which a thrust load is applied to a thrust cylindrical roller bearing and deformed unevenly.

  The present invention will be described in detail with reference to the drawings.

  In the thrust cylindrical roller bearing, when the backup width Lh on the outer ring 7 side and the backup width Ls on the inner ring 6 side are greatly different (Ls <Lh), as shown in FIG. 4, when the thrust load Fa is applied, the roller An excessively high surface pressure is locally generated on the inner diameter side of 8, which causes peeling of the raceway surface and the like. For this reason, it is desirable that the backup widths of the inner and outer rings are substantially equal. However, there is a demand for weight reduction and a low moment of inertia especially on the shaft 1 side. Since there are many parameters that define the shape of the part, it is often difficult to set the backup width Ls large.

  Therefore, when Ls <Lh, a protrusion 13 having a hollow circular cross section is provided on the end face of the outer ring that contacts the housing [see FIG. 1 (a) and FIG. 2]. The radial length Lt of the protrusion is the same as the inner ring side backup width Ls. When Ls> Lh, a projecting portion having the same radial length as the outer ring side backup width Lh is provided on the end surface in contact with the inner ring housing. Due to this protrusion, the backup width of the inner ring 6 and the outer ring 7 becomes the same length, and even when the thrust load Fa is applied, the elastic deformation amount of the inner ring 6 and the outer ring 7 becomes substantially equal [see FIG. 1 (b)].

  As a result, the non-uniformity in the radial direction of the bearing clearance d due to the difference in deformation between the two has been reduced, and a substantially uniform bearing clearance d in the radial direction can be obtained even during operation of the bearing. Therefore, it is possible to prevent local increase in roller surface pressure and occurrence of edge load, and accompanying abnormal wear, raceway surface, and peeling of the roller surface.

1 Shaft 2 Inner ring positioning step 3 Inner ring side backup surface 4 Housing 5 Outer ring side backup surface 6 Inner ring 7 Outer ring 8 Cylindrical roller 13 Protruding portion Ls Inner ring side backup width Lh Outer ring side backup width Lt Radial length Fa of protruding portion Thrust load d Bearing clearance

Claims (1)

When there is a difference in the backup width between the inner ring and the outer ring, a cylindrical axial protrusion on the backup surface side is provided on the raceway ring having a relatively large backup width among the backup widths of the inner and outer rings. A thrust cylindrical roller bearing characterized in that a radial contact length of a hollow circular contact surface between a portion and a shaft or a housing is the same as a backup width of an opposed race ring.

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