Modeling and characteristic analysis of engaging process during gear shifting of mechanical transmissions(PDF)
长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]
- Issue:
- 2018年01期
- Page:
- 112-119
- Research Field:
- 汽车与机械工程
- Publishing date:
Info
- Title:
- Modeling and characteristic analysis of engaging process during gear shifting of mechanical transmissions
- Author(s):
- CHEN Hong-xu; LU Zi-wang; WANG Li-jun; TIAN Guang-yu
- State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
- Keywords:
- automotive engineering; engaging process; numerical simulation; impact; hybrid system; rotational speed difference; relative position
- PACS:
- U463.2
- DOI:
- -
- Abstract:
- The engaging process of engaging sleeve and clutch gear is the key phase influencing the gear shifting performance of mechanical transmissions. During an engaging process, collision occurred when engaging sleeve and clutch gear contacted at the end of the tooth chamfer, their relative speed suddenly changed, and their coupling relationship and dynamic equations also changed. In order to obtain an accurate mathematical model and characteristics of the engaging process of mechanical transmission, a hybrid automaton model was built to describe the engaging process through multi-body dynamics theory and hybrid system methodology. In this model, three sets of differential equations were built to describe the dynamic characteristics of engaging sleeve and clutch gear under different coupling relationships during an engaging process. Poisson recovery coefficient was introduced to build four sets of difference equations to describe the rotational speed of clutch gear, the axial movement speed of engaging sleeve and the sudden change of rotational speed during the collision process. Based on the hybrid automaton model, simulation analysis was carried out in the MATLAB environment. The trajectories, the engaging duration and the maximum impact of engaging sleeve and clutch gear during their engaging process were obtained. The effects of the shifting force and the initial rotational speed and position of engaging sleeve relative to clutch gear on engaging performance were analyzed. The results show that the relative position of engaging sleeve and clutch gear has significant effect on the engaging duration and the maximum impact. If the rotational speed difference of engaging sleeve and clutch gear is within limit, the engaging duration is relatively short, and a big rotational speed difference will cause an exponential rise of engaging duration, a bigger rotational speed difference of engaging sleeve and clutch gear will cause a bigger engaging impact. When increasing the shifting force, the engaging duration will shorten but the impact will increase. When designing the control system of automated mechanical transmission, the optimal shifting force, relative rotational speed and position should be adopted as control parameters to shorten power interruption time and reduce shifting impact according to the gear shifting characteristics of mechanical transmission.
Last Update: 2018-02-06