Real time bearing load sensing

A method for determining real time load values experienced by a bearing comprising:

• providing a bearing including an inner race mounted to an axle, an outer race supporting a bearing carrier, and a plurality of rolling elements disposed therebetween, one of the inner race, the outer race, the axle or the bearing carrier including an annular channel extending circumferentially about the bearing which provides an unsupported cylindrical surface to allow bending deflection in the axial direction of the bearing at that point;
• mounting a plurality of strain gages to the unsupported surface of either the inner race or the outer race of the bearing at bearing rolling element positions and axially aligned with the bearing;
• collecting the strain data from each of the plurality of strain gages under each of a plurality of known load ratio and load conditions;
• calculating a strain gage ratio for each combination of load ratios and loads;
• averaging the strain gage ratios for each of the plurality of load ratios;
• calculating a first equation by completing regression analysis to derive a second order equation that defines the ratio of the loads as a function of the ratio of the strain gages;
• calculating a second equation by completing a regression analysis to derive an equation defining the sum of the radial and axial loads as a function of the strain on the heaviest loaded strain gage, the equation having a unique slope for each load ratio;
• calculating a third equation by completing a regression analysis to derive a equation that defines the slope of the second equation as a function of the load ratios;
• calculating a fourth equation by combining the second equation and the third equation to develop an equation defining the sum of the radial and axial loads as a function of the strain and the ratio of the radial load to the axial load;
• mounting the bearing to a machine and using the machine under loaded conditions;
• collecting the strain gage data produced as the machine experiences varying load conditions;
• inputting the strain gage values taken under unknown load conditions into the first equation to solve for the ratio of the actual radial loads to the actual axial loads;
• inputting the ratio of actual radial to actual axial loads into the fourth equation to solve for the sum of actual radial and actual axial loads;
• using the sum of actual radial and actual axial loads and the ratio of the actual radial and actual axial loads to calculate the actual radial load and the actual axial load being placed on the bearing.

A method for determining real time load values experienced by a bearing comprising:

• providing a bearing including an inner race mounted to an axle, an outer race mounted to a bearing carrier, and a plurality of rolling elements disposed therebetween, one of the inner race, the outer race, the axles or the bearing carrier including an annular channel extending circumferentially around the bearing which provides an unsupported surface to allow bending deflection in the axial direction of the bearing at that point;
• mounting a plurality of strain gages to the unsupported surface of either the inner race or the outer race of the bearing assembly at bearing rolling element positions and axially aligned with the bearing
• collecting data of the strains measured at each strain gage under a plurality of known load conditions;
• correlating the strains measured at each strain gage position to the load at that position for each of the plurality of load conditions and using regression analysis of the strain data for each of the different load conditions to develop a first equation for each strain gage position defining the load at each strain gage position as a function of the strain measured at that position;
• mounting the bearing to a machine and using the machine under loaded conditions;
• collecting the strain gage data produced as the machine experiences varying load conditions;
• using the equations for each strain gage position to convert the strain measured at each strain gage position into a load at that position;
• extrapolating between strain gage positions to calculate a load for rolling element positions that did not have a strain gage mounted thereon;
• summing the loads experienced by the bearing at each rolling element position to determine the total load being experienced by the bearing.