Advancement of electro-mechanical dual acting pulley continuously variable transmission using independent actuators
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Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Teknologi Malaysia
Abstract
Electro-Mechanical Dual Acting Puley Continuously Variable Transmision (beter known as EMDAP CVT), developed in Universiti Teknologi Malaysia, features two actuators: a primary puley actuator (consists of a primary DC motor and a set of primary power screws mechanism) and a secondary puley actuator (consists a secondary DC motor and a set of secondary power screws mechanism). To vary CVT ratio (rCVT), the position primary puley sheaves (Xpri) is adjusted by the primary puley actuator, while the position of puley sheaves (Xsec) is changed by the secondary puley actuator depending on Xpri position. Such dependency, unfortunately, causes a complicated proces to vary rCVT since it involves two DC motors, two position sensors and an algorithm convert Xsec based on Xpri. Hence, the objective of this research is to develop independent actuators (IA) for EMDAP CVT so thathis complication eliminated. IA consists of a ratio actuator that comprises a DC motor (ratio motor) adjust both Xpri and Xsec to vary rCVT, and a clamping force actuator that comprises a DC motor (clamping motor) actuate only the secondary power screws Xps_sec) for CVT belt’s action. This research is divided into thre phases: namely, the design phase, the analyses phase, and thexperimental phase. The aim of phase is to finalize the design concept of EMDAP CVT with IA. Here, relevant criteriand requirements for the concepts are identified; then, five design concepts are introduced. The final concept iselected based on the asesments of al using the House of Quality. Next, the objective of analyses phase is to study the significance the non-linearity betwen Xpri and Xsec during the changing of rCVT as a preparation for the prototype’s development. This non-linearity compensated by disc springs in secondary puley, thus it is defined as changes in the disc springs’ deflection, ?S. Minimizing ?S is crucial to minimize the variation the clamping force, maximize the springs’ lifespan, friction works and avoid excesively high ratio motor’s torque. Based on mathematical equations for varying rCVT, the relationships betwen ?S and CVT belt’s pitch length (L) ratiof Xpri:Xps_sec are investigated within rCVT of 0.60 to 3.0. Thevaluated Ls are 645m (Belt Type 901018) and 610m (Belt Type 901057) and from these, the later iselected since it reduces ?S by about 23% as compared to the former. The investigation also shows that can be furthereduced by around 36-45% by using Xpri:Xps_sec of 1:0.9, as oposed to 1:1. These findings are used finalize the concept’s parameter for the prototype development. Finaly, the objective of thexperimental phase is to prove the workability of EMDAP CVT with IA. In thexperiment, the prototype capable of varying rCVT from circa 0.60 to 3.0 by using only ratio actuator and the experimental data ?S show very smal diferences with analytical data, ranging from -0.05m to 0.3m. As a conclusion, EMDAP CVT with IA has ben sucesfuly developed, and it eliminates the dependency betwen two actuators the original EMDAP CVT, thus making rCVT varying procesignificantly simpler
Description
Thesis (Ph.D (Mechanical Engineering))
Keywords
Automotive engineering, Actuators