Design Of Hydro-Mechanical Continuously Variable Transmission Used On The Unroad Vehicle And Research On The Control System Of Variable PUMP

The Hydro-mechanical Continuously Variable Transmission (HMCVT) transmits both the hydraulic power and mechanical power. Relying on the controlled speed of the hydraulic transmission and the high efficiency of the mechanical transmission of the mechanical transmission, it realizes stepless speed change. The transmission device which used on the high power vehicles not only can improve the power performance and fuel economy, but also can reduce the complexity of the operation. This paper analyzed the flow and confluence way of mechanical and hydraulic power、put forward and optimized the overall scheme of the HMCVT、established the theoretical model of the optimized scheme and determined its parameters、designed the structure of the HMCVT and developed test prototype、established its simulation model and did the research on the characteristics of transmission. The completed work and achieved results are generalized as follows:1. Based on the characteristics of the fixed axis gear and the planetary gear institutions, this paper presented six schemes of points speed remit torque and six schemes of points torque transfer speed which can be used as the transmission structure of the HMCVT, established their total ratio theory model and analyzed the relation between the total ratio and the displacement ratio using the software MATLAB. Furthermore, this paper analyzed the speed, torque and power characteristics of the six schemes of points torque transfer speed.The results showed that,the relation between the total ratio and displacement ratio of the scheme of the schems of points torque transfer speed is linear,and the range is large,this kind of scheme is suitable to be uses as the combination form of Hydraulic mechanical transmission.2. Based on a single planet row to realize confluence,this paper presented three differet schemes of the HMCVT,eatablished the theory transmission ratio model,analyzed the speed cohesion conditions. The results showed that: it can not realize stepless speed change if we only use a single planet row to realize confluence. Based on the working principle of the double planetary row, this paper presented eight kinds of double row converge and analyzed the feasibility of the eight kinds of double row converge. The results showed that: the parameter of the scheme of HI have a wide range both on the irrespective transmission and the means transmission, it is suitable to be used as the device of the double row converge. Furthermore, this paper analyzed the characteristics of the irrespective transmission and the means transmission, did the research on the structure relationship of the two models, this paper selected the means transmission. At last, this paper presented three schemes which based on the double row converge and the means transmission, analyzed their advantage and disadvantage and determined the optimized scheme.3. This paper established the output speed theory model according to the optimized scheme of HMCVT, and deduced the relation of the transmission ratio based on the condition of means transmission and the continuously speed among every phrase. Base on the form and transmission ratio、the characteristic parameter of the confluence planet row and the type of the hydraulic elements, this paper determined the theory transmission ratio according to the minimum ratio and ensured the parameter of gear according to the working condition. Furthermore, this paper analyzed the relation between the transmission ration and the displacement ratio, this paper also analyzed the relation between the vehicle speed and the displacement ratio. The results showed that: the designed transmission parameter not only can realize the continuously speed among every phrase, but also can realize the maximum and the minimum speed.4. This paper determined the torque and speed requirement of the clutch and designed the connecting device according to the working condition of the clutch, manufactured the clutch with the cooperation with Shanghai yuyi mechanical company. Furthermore, this paper designed the structure of the shaft、presented and optimized the structure of the double planet row converge、designed the structure of the later transmission presented a structure to support、lubricate and chilling the planer row、designed the structure of the gear-box、analyzed the interference using the software Solidworks and manufactured the test prototype.5. In the software SimulationX, this paper established the engine model、established and optimized the control model of the hydraulic pump and motor、established the control model of the clutch and the double planet row confluence and proved their correctness and feasibility. At last this paper did the simulation of the whole vehicle model which loads the HMCVT. The results showed that: the designed product can satisfy the need of working condition, the established model can reflect the performance of the HMCVT.6. This paper builded the test bench of the hydraulic pump control system, developed the test system of the pump and did the control characteristics of the hydraulic pump. The results showed that: the pump control system that this paper used can achieve two-way displacement change of the pupm well; through adjustment of voltage of the proportional electromagnetic, it can realize the speed control and reversing of the hudraulic motor.Through the research of this paper, it can provide support for the later experiment of the HMCVT and the control system of the HMCVT, it also provide support for doing reaserach on the characteristic of the hydraulic system. And this research is of important theoretical significance and practical value to promote the application of the HMCVT to vehicle and to improve the vehicle performance and fuel economy.