Experimental Studies of the Wear on the Rotors’ Working Surfaces of a Planetary Hydraulic Motor

During the operation of planetary hydraulic motors, wear of the working surfaces of their rotors occurs. Therefore, the experimental study of the effect of wear on the working surfaces of the planetary hydraulic motor rotors on the dynamics of changes in its output characteristics is relevant. Studies show that with an increase in the diametral clearance, the theoretical torque decreases by 3.5%, changing from 1450 N·m to 1400 N·m. The theoretical rotation frequency has significant deviations up to 47%, varying from 150 min−1 to 80 min−1. The theoretical flow rate of overflows reaches 10 l/min at a critical value of a diametral gap of 0.4 mm. When changing the diametral clearance, the real torque sharply decreases by 42% to 720 N·m, and the real flow rate of the overflows sharply increases to 7.5 l/min at a maximum value of the diametral gap of 0.25 mm. The decrease in the real rotation frequency by 65.5% occurs quite dynamically in the range from 145 min−1 to 50 min−1. Such a change in the real rotation frequency occurs due to “additional” movements of the inner rotor and an increase in the actual flow rate of overflows. Experimental torque, leakage flow, and rotation frequency change similarly to real values, respectively, having the exact numerical values. It has been established that the critical value of the diametral gap is 2.5 times less than the same value for a planetary hydraulic motor with the theoretical rotor.