Abstract:To solve the limited speed range and low load capacity of singlerow planet hydraulic mechanical transmission, a new compound hydraulic machinery continuously variable transmission(HMCVT) was proposed. The unified relationship of HMCVT characteristics was established. The hydraulicmechanical transmission was simulated by AMESim software. The HMCVT prototype was tested to obtain the performance curve and compared with that of the coupled output transmission. The results show that the actual HMCVT speed characteristic value is consistent with theoretical value. The compound hydraulic mechanical transmission has continuously variable speed function. The compound HMCVT has good speed linearity with easy adjustment ability. The hydraulic powersplit ratio of HMCVT is from 0 and 1.0 without power cycling and with high mechanical efficiency.