Simulation of Rolling Contact Fatigue Strength for Traction Drive Elements

Abstract

A simulation of the rolling contact fatigue strength of a traction drive element was proposed. The simulation can account for both the distribution of sizes of inclusions in the element material and the influence of traction forces at the element surface. The shear strength of the matrix structure surrounding an inclusion was estimated with an equation. The hardness distribution and the Weibull distribution of inclusion dimensions, which were necessary parameters to calculate the rolling contact fatigue strength, were determined by observation of an actual test specimen. And the rolling contact fatigue strength was compared with the distribution of shear stresses in a roller affected by traction forces. A simulation assuming the same traction coefficient as that in the experiment predicted a rolling contact fatigue strength of 810 MPa with a standard deviation of 39.2 MPa, which differed from the experimental value by only 2.5%. Simulations of the rolling contact fatigue strength were then carried out while varying the traction coefficient. The contact force resulting in failure was observed to fall as the traction coefficient increased and the torque capacity increased. Thus, the torque capacity increases with the traction coefficient, regardless of changes in the rolling contact fatigue strength.

Simulation of rolling contact fatigue strength for traction drive elements (comparison with fatigue test)

“…These inclusions lowered the fatigue strength. In such cases, the maximum value max area = 51.6 μm for the inclusion area was estimated with the statistics of extremes (Murakami, 2002) and used as the upper limit of the area of generated inclusions (Narita et al, 2013).…”

“…The surface hardness H 1 was 667 Hv, the core hardness H 3 was 430 Hv, and the effective case depth d eff was 0.7 mm. We applied the approximated hardness at any depth z (Narita et al, 2013) obtained from observation of actual rollers: Vol.12, No.1 (2018) The approximated curve of hardness Hv according to Eqs. (6) and (7) is also shown in Fig.5.…”

“…It would be very useful for strength design if the scatter could be estimated by simulation. The authors developed a simulation analysis of the rolling contact fatigue strength of traction drive elements (Narita et al, 2013(Narita et al, , 2014 by accounting for both the distribution of sizes of inclusions in the element material and the influence of traction forces employing Masuyama's method (2002aMasuyama's method ( , 2002b. Though, the verification of estimation accuracy is untouched.…”

Evaluation of load capacity of gears with an asymmetric tooth profile

“…(3) (Masuyama et al 2002) and (4) (Narita et al 2013) from the results of experiments on the bending fatigue of a gear and on the surface damage of a steel roller: …”

Effect of crowning radius on rolling contact fatigue strength for traction drive elements (Evaluation by simulation)

“…It would be very useful for strength design if the scatter could be estimated by simulation. The authors developed a simulation analysis of the rolling contact fatigue strength of traction drive elements (Narita et al, 2013) by accounting for both the distribution of sizes of inclusions in the element material and the influence of traction forces employing Masuyama's method (Masuyama et al, 2002a). When a simulation was performed using the same material with the same distribution of inclusions measured in the test rollers and assuming the traction coefficient found in the experiment, the calculated rolling contact fatigue strength matched the experimental findings with an error of 2.5%.…”