JP2014009739A - Thrust cylindrical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent trouble such as edge load or exfoliation from being incurred by making contact surface pressure between a roller and a raceway surface uneven from an inner diameter side of a bearing ring to an outer diameter side since, in use of a thrust cylindrical roller bearing, there are many cases where a backup width of an inner ring and a backup width of an outer ring are considerably different, and a difference is generated by a thrust load in elastic deformation between the inner ring and the outer ring.SOLUTION: Flexural rigidity is improved by increasing axial thickness of a bearing ring having a relatively smaller backup width between inner and outer rings. In the case where a backup width Ls of an inner ring 6 is smaller than a backup width Lh of an outer ring 7, axial thickness of the inner ring 6 is increased, such that the elastic deformation may be equal substantially between the inner ring 6 and the outer ring 7. Thus, a bearing gap is prevented from being uneven radially.

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. 3).

  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. Using multiple rows of rollers reduces 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 mounted has a step in the radial direction to ensure the support rigidity and positioning of the inner ring, but a step for backup over the entire radial length of the inner ring so that the inner ring does not deform. 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 problems, and even if elastic deformation occurs in the inner and outer rings due to a thrust load, the deformation amount of both is made substantially equal to prevent the 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 between the backup widths of the inner and outer rings, the backup width is increased by increasing the axial thickness of the raceway with a relatively small backup width of the inner and outer rings, compared to the other raceway. Improves the bending rigidity against the thrust load of the raceway with a small diameter.

  By increasing the thickness of the inner and outer rings with the relatively small backup width and improving the bending rigidity, the inner ring and the outer ring can exhibit substantially the same elastic deformation state even when a large thrust load is applied. become. Therefore, the parallelism of the raceway surface is not easily lost, and the bearing clearance is prevented from becoming uneven. As a result, it is possible to suppress the local increase of the roller surface pressure, the occurrence of an unbalanced load, and the wear and separation associated therewith.

It is drawing which shows typically the thrust cylindrical roller bearing which increased the thickness of the axial direction of the inner ring | wheel with a relatively small backup width | variety. It is sectional drawing which showed typically the state which made the elastic deformation amount of the inner and outer ring | wheels substantially the same at the time of a thrust load load by increasing the thickness of an inner ring | wheel. It is sectional drawing which shows the state which incorporated the general thrust cylindrical roller bearing in the apparatus. FIG. 5 is a cross-sectional view schematically showing a state in which a thrust load is applied to a general thrust cylindrical roller bearing and inner and outer rings are deformed unevenly.

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

  In the thrust cylindrical roller bearing as shown in FIG. 3, 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), the outer ring is loaded when the thrust load Fa is applied. The inner ring 6 is greatly elastically deformed as compared to 7 (see FIG. 4). For this reason, an excessive load pressure is generated on the inner diameter side of the roller 8, which causes the raceway surface to peel off. 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 a large backup width.

  Therefore, in the present invention, by increasing the axial thickness of the bearing ring in the inner and outer rings with a relatively small backup width, the bending rigidity of the bearing ring with respect to the thrust load is improved, and the thrust load is applied. Even in this state, the amount of elastic deformation of the inner and outer rings is made substantially equal. Specifically, when Ls <Lh, the axial thickness of the inner ring 6 is increased. Thereby, the amount of elastic deformation of the inner ring 6 and the outer ring 7 due to the thrust load Fa becomes substantially equal (see FIG. 2). When Ls> Lh, the axial thickness of the outer ring 7 is increased. The thickness of the bearing ring is determined based on the magnitude of the thrust load, the backup widths Ls and Lh of the inner and outer rings, and the thickness of the bearing ring having a relatively large backup width.

  By increasing the axial thickness of the bearing ring having a relatively small backup width among the inner and outer rings and improving the bending rigidity, the amount of elastic deformation of the inner and outer rings due to the thrust load load becomes substantially equal, and the bearing clearance d Nonuniformity in the radial direction is reduced. As a result, a substantially uniform bearing clearance d in the radial direction can be obtained even during the operation of the bearing. Therefore, local increase in roller surface pressure and occurrence of edge load, and associated abnormal wear, raceway surface, and peeling of the roller surface. Can be prevented. Further, in the present invention, it is not necessary to use a spacer or the like, so that the above object can be achieved at low cost.

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 Ls Inner ring side backup width Lh Outer ring side backup width Fa Thrust load d Bearing clearance

Claims (1)

  When there is a difference in the backup width between the inner ring and the outer ring, the bearing ring with the smaller backup width among the backup widths of the inner and outer rings is made thicker in the axial direction than the other bearing ring. Thrust cylindrical roller bearing.

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