Research On Character And Simulation Of Hydraulic Mechanical Transmission

At present, the transmission used in vehicles may be divided into the step transmission and the continuously variable transmission, in the step transmission, manual transmission and automatic mechanical transmission are applied on the most vehicle and the freight vehicle. But the step transmission only can realize several fixed speed ratios, therefore, it can not guarantee the engine always work in the best power and the best efficient work area. Automatic mechanical transmission also only enable the engine work nearly in the best power and the best fuel oil efficient work area. Continuously variable transmission has made up this flaw. In the mechanical continuously variable transmission. The metal belt continuously variable transmission is widely applied , but it's power is small, only be used on some cars. The fluid mechanical transmission can transmate bigger power and can realize the continuously variable speed ,but the efficiency is low. The hydro- mechanical continuously variable not only can realize the continuously variable speed, but also the efficiency is higher, therefore, it start to be developed, Because it develops late, it is not very mature, this paper has done some preliminary studies in it. I hope that I can understand the Characteristic of the hydraulic machinery continuously variable transmission and the entire vehicle traveling rule.Hydro-mechanical continuously variable transmission(simplified by HMCVT) consists of the four functional components: mechanical transmission, hydraulic transmission, diffluence element and convergent mechanism. It was a sort of hydraulic power current and mechanical power current parallel new style transmission form,through the medium of mechanical transmission realize high efficiency,through mechanical transmission and hydraulic transmission adjoint realize continuous variable speeds, Hydro-mechanical transmission has a better developing foreground, comparing several kinds of continuous variable transmission, especially heavy duty car. In consideration of this,this paper research about HMCVT.1.This paper introduced different kinds of transmission, including hydro-methanical continuously variable transmission, analyses continuously varible transmission's developing process and study actuality in the world. Finally, confirms this paper's research sense and research content.2.Introduce clearly double flow driving theory, on foundation of this theory, research HMCVT. Through different kinds of planet mechanism, I choose clearly rational forward and reverse planet mechanism. In terms of engine type and power,I select clearly becoming hydraulic pump and hydraulic motor system. On the basis of continously variable speeds,ascertain clearly transmission severalty segmental transmission ratio and planet row parameter.3. The model of hydraulic motor rotation rate and hydraulic pump tray corner is established ,and is simulated in Matlab/simulink at wholly working process, showed that hydraulic pump and hydraulic motor is rational.4. The simulink model of CVT and car is established, simulated engine speed and car velocity, versus entire car from first time step to most car velocity at different throttle opening.It is clear that HMCVT is heavy vehicular ideal transmission form, not only realize continuously variable speeds,but also return efficiency high. Control department is not very complex as well. The comparation of some kinds of cent and confluence formal prove that withal fixed axis gear shunt and withal planet row collective cent is the ideal structure. The maximum power output of geometric proportion continuous mode is constant,low speed segmental torque is large,high speed segmental torque wane slowly. the initial segment is benefit to adjust velocity, therefore, series segmental control shift effect is more and more notice and benefit to rapidly run up to top speed. Wherefore,geometric proportion type hydraulic machinery continuously varible transmission is suitable for vehicle lay a course. Simulation demonstrate the hydraulic pump and hydraulic motor is reasonable,the continuously variable transmission and entire car simulink model is established, simulated out motor rotation rate and car velocity variance at different throttle opening. This paper showed that engine is able to rapidly run to optimum regime,car velocity is calm and conform with vehicular require at first time step. This paper have definite reference sense to far further research of hydro- mechanical continuous variable speeds. This is simple transmission according to theory. Continuously variable transmission and entire car model is not very right, preferable mode is supposed to be power bond graph.In a word, we should make a further research in several aspects, for example, the rule of continuously variable transmission, the more precise continuously variable transmission and entire car model established power bond graph.