Roller circle assembly for heavy machinery

Abstract

A roller circle assembly for heavy machinery includes an upper circular rail and a lower circular rail concentrically arranged about a central axis, and tapered rollers between the upper and lower rail. Each tapered roller includes a flange having an angled and convex flange contact surface that contacts the lower rail. The lower rail and/or the upper rail can include an angled surface configured for contact with the flange contact surface. The geometry of the rollers and the lower rail are configured to reduce the stresses applied to the rollers and lower rail due to contact between the flange contact surface and the angled surface.

What is claimed is: 
     
         1 . A heavy earth-moving machine comprising:
 a lower structure;   an upper structure supported by the lower structure and rotatable with respect thereto;   a substantially circular lower rail mounted on the lower structure;   a substantially circular upper rail mounted on the upper structure; and   a plurality of tapered rollers engaging and positioned between the upper rail and the lower rail, each of the plurality of tapered rollers including:
 a substantially frustoconical body portion having an enlarged end, a reduced end, and a roller surface extending between the enlarged end and the reduced end, the body portion defining a roller axis; and 
 a flange portion extending radially from the reduced end of the body portion and including a crowned, convex flange contact surface facing toward the enlarged end, wherein the crowned, convex flange contact surface defines an arc of a circle having a center point that is offset from the roller axis. 
   
     
     
         2 . The heavy earth-moving machine of  claim 1 , wherein the lower rail includes an inner rail surface, an upper surface that engages the roller surfaces of each of the plurality of rollers, and a transition portion between the inner rail surface and the upper surface, and wherein the flange contact surface of each of the plurality of rollers is engageable with the transition portion to substantially maintain alignment of the plurality of rollers with respect to the lower rail in response to loads applied to the upper structure. 
     
     
         3 . The heavy earth-moving machine of  claim 2 , wherein the transition portion includes a substantially flat portion that is angled with respect to the inner rail surface, and a rail radius portion extending between the substantially flat portion and the upper surface. 
     
     
         4 . The heavy earth-moving machine of  claim 3 , wherein an angle between the substantially flat portion and the inner rail surface is between 2 degrees and 5 degrees. 
     
     
         5 . A tapered roller for a roller circle assembly for heavy machinery, the roller circle assembly rotatably supporting an upper structure of the heavy machinery above a lower structure of the heavy machinery, the tapered roller comprising:
 a substantially frustoconical body portion having an enlarged end, a reduced end, and a roller surface extending between the enlarged end and the reduced end, the body portion defining a roller axis; and   a flange portion extending radially from the reduced end of the body portion and including a crowned, convex flange contact surface facing toward the enlarged end, wherein the crowned, convex flange contact surface defines an arc of a circle having a center point that is offset from the roller axis.   
     
     
         6 . The tapered roller of  claim 5 , wherein the roller surface includes a central portion and an inner edge relief portion extending from the central portion toward the flange, and wherein the inner edge relief portion diverges axially inwardly and away from a tangent line extended from the central portion toward the flange portion. 
     
     
         7 . The tapered roller of  claim 6 , wherein the convex flange contact surface transitions into the inner edge relief portion via an inner radius. 
     
     
         8 . The tapered roller of  claim 5 , wherein the flange contact surface defines a curve that lies in a section plane that is coplanar with the roller axis, and wherein a chord line drawn between outer ends of the curve defines an acute angle between 1 degree and 5 degrees with respect to a reference plane that is perpendicular to the roller axis and substantially aligned with a roller end surface proximate the reduced end. 
     
     
         9 . A heavy earth-moving machine comprising:
 a lower structure;   an upper structure supported by the lower structure and rotatable with respect thereto;   a substantially circular lower rail mounted on the lower structure, the lower rail including an inner rail surface, an upper surface, and a transition portion between the inner rail surface and the upper surface that is angled with respect to the inner rail surface;   a substantially circular upper rail mounted on the upper structure; and   a plurality of tapered rollers engaging and positioned between the upper rail and the lower rail, each of the plurality of tapered rollers including:
 a substantially frustoconical body portion having an enlarged end, a reduced end, and a roller surface extending between the enlarged end and the reduced end, the body portion defining a roller axis; and 
 a flange portion extending radially from the reduced end of the body portion and including a crowned, convex flange contact surface facing toward the enlarged end, wherein the crowned, convex flange contact surface contacts the transition portion along an elliptical contact area on the transition portion. 
   
     
     
         10 . The heavy earth-moving machine of  claim 9 , wherein the transition portion includes a first transition point and a second transition point, and wherein all contact between the crowned, convex flange contact surface and the lower rail occurs between the first and second transition points. 
     
     
         11 . The heavy earth-moving machine of  claim 10 , wherein the first transition point is disposed proximate the inner rail surface of the lower rail, and the second transition point is disposed proximate the upper surface of the lower rail. 
     
     
         12 . The heavy earth-moving machine of  claim 10 , wherein elliptical contact area extends between the first and second transition points, and the crowned, convex flange contact surface moves along the elliptical contact area between the first and second transition points in response to loads applied to the upper structure. 
     
     
         13 . The heavy earth-moving machine of  claim 10 , wherein the crowned, convex flange contact surface contacts the transition portion at a point that is approximately one third of a distance between the first transition point and the second transition point when no loads are applied to the upper structure. 
     
     
         14 . The heavy earth-moving machine of  claim 10 , wherein an area extending between the first and second transition points is substantially flat. 
     
     
         15 . The heavy earth-moving machine of  claim 14 , wherein the transition portion includes a rail radius disposed between the substantially flat area and the upper surface of the lower rail. 
     
     
         16 . The heavy earth-moving machine of  claim 14 , wherein an angle between the substantially flat portion and the inner rail surface of the lower rail is between approximately 2 degrees and 5 degrees. 
     
     
         17 . The heavy earth-moving machine of  claim 9 , wherein the crowned, convex flange contact surface defines a curve that lies in a section plane that is coplanar with the roller axis, and wherein a chord line drawn between outer ends of the curve defines an acute angle between 1 degree and 5 degrees with respect to a reference plane that is perpendicular to the roller axis and substantially aligned with a roller end surface proximate the reduced end. 
     
     
         18 . The heavy earth-moving machine of  claim 9 , wherein the crowned, convex flange contact surface defines an arc of a circle having a center point that is offset from the roller axis. 
     
     
         19 . The heavy earth-moving machine of  claim 9 , wherein the roller surface includes a central portion and an inner edge relief portion extending from the central portion toward the flange, and wherein the inner edge relief portion diverges axially inwardly and away from a tangent line extended from the central portion toward the flange portion. 
     
     
         20 . The tapered roller of  claim 19 , wherein the crowned, convex flange contact surface transitions into the inner edge relief portion via an inner radius.