Diagnostic and in-service inspection of torsion strains in a continuously variable mechanical transmission with an internal force function

摘要

The paper discusses the enhancement of the energy efficiency of motor vehicles with conventional engines when using a continuously variable mechanical transmission with internal force function control. Such a transmission has torsion shafts working in torsion under conditions of random cyclic loading at a frequency corresponding to the ICE shaft rotation speed. The fatigue strength of torsion shafts can be a limitation on the operating life of the entire transmission. Technological measures increasing the fatigue limit of the torsion shaft material are analyzed. Developing the elastic strains of torsion bars is theoretically considered. The theoretical strain cycle fluctuates with the asymmetry ratio R = 0. The amplitude of the elastic strain is determined by the external load. The test procedure for a prototype vehicle with an engineering specimen of a transmission in specific motor vehicle operating modes is presented. The need for the ongoing monitoring to limit torsional strain by the control system is shown. According to the field test results, the nature of torsion bar loading cycles in operating conditions is estimated in detail. In most operating modes, the experimental character of torsion bar loading has a reversed strain cycle with the negative strain ratio R = -0.04 ... -0.79. The inexpediency of torsion bar hardening is shown. Fragments of oscillograms demonstrating elastic strains of the torsion bars and distribution of the mean and amplitude values of the strain cycles for typical operating conditions are given.