Method and Test Bench for Hydro-Mechanical Continuously Variable Transmission Based on Multi-Level Test and Verification

Abstract

According to the structural characteristics of Hydro-mechanical continuously variable transmission (HMCVT), a multi-functional test bench was developed, and the basic structure, working principle, and test functions of the test bench were introduced. The test bench has the following characteristics: To analyze the impact of mechanical transmission and hydraulic transmission on the HMCVT transmission system, the performance can be tested separately by using a test bench; the coupling characteristics of the hydraulic transmission and mechanical transmission can also be tested; it can also test and verify the performance of the HMCVT transmission system and the control system; the test bench has a simple structure, diverse functions, and convenient operation. Using the multi-functional test bench, this paper proposes a method of multi-level test and verification. Through this method, the simulation models are revised and improved many times, and the accuracy of the models is improved, which are consistent with the physical model, and eventually, the accuracy of the simulation result is improved. This method is used to test and verify the hydraulic transmission system, analyze the characteristics of the hydraulic transmission system, and verify the feasibility and practicability of the multi-level verification method.

Lubrication Reliability and Oil Churning Loss of Differential Gear Trains in a Mechanical-Hydraulic Coupling Mechanism

“…A test bench (Fig. 21) was built using a motor, transfer gearbox, speed-torque sensors, differential gearbox (replaceable), and dynamometer [6]. Working conditions 1-6 (Table 1) and 11-16 ( oil churning and friction losses from bearings, gears, and couplings.…”

“…To analyze the oil churning losses of DGTs more comprehensively, a differential gearbox with a planet carrier output shaft (DGPCOS) and a differential gearbox with a ring gear output shaft (DGRGOS) in [6] is taken as the research objects respectively. The mechanical-hydraulic coupling mechanism, i. e. the differential gearbox studied in this paper, mainly consists of two input shafts, a fixed axis gear pair, a sun gear, bearings, planet gears, a planet carrier, a ring gear, and a casing, as shown in Fig.…”