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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Observations on Dynamic Characteristics of Roller Gear Cams Due to Various Torque Compensations

Liu, Chung-Han 21 July 2000 (has links)
Roller gear cam (RGC) mechanisms are widely used in modern industries. While operated at high speeds, the indexing precision of these devices will be influenced by their dynamic characteristics. In this study, the Bond Graph Method is employed to construct a mathematical model to simulate the dynamic responses of RGC mechanisms. Meanwhile, associated experiments will be made to verify the effectiveness of this model. The influences of torque compensation mechanisms and different cam motion curves affecting the dynamic response of a RGC mechanism are observed. And the results show that the torque compensation mechanism is effective to the dynamic performance, and high-speed stability of a RGC mechanism. Besides, the simulated results also indicate that the kinematic properties of cam motion curves have certain influences on the residual vibrations of the system.
2

A Study on the dynamic Behavior of the Roller Gear Cam System Using Different Torque Compensation Mechanisms

Hu, Chin-Che 01 July 2001 (has links)
Roller Gear Cam mechanism¡]RGC¡^has been used widely in different automation mechanisms and all kinds of orientation mechanism. High speed and high accuracy of the RGC system is a tendency in high production automation. The interaction between the driving speed and torque of a high speed RGC system is investigated in this work. The effect of adding a torque compensation cam¡]TCC¡^on the improving of indexing precision of a RGC system is investigated in this thesis. The dynamic responses of a RGC system driven by a DC motor are conducted. Dynamic equations of the intermittent- motion of a RGC driven system are derived by using the Lagrange¡¦s equation with the assumption of dual-stiffness. Furthermore, the effect of adding a torque compensation mechanism¡]TCM¡^ such as torque compensation cam¡]TCC¡^ or idle wheel on the improving of indexing precision of a RGC system is investigated in this work. The sixth order Runge-Kutta iteration method is employed in the system¡¦s responses simulation. Variations of the driving torque, driving speed and residual vibration of a RGC system with different torque compensation devices are analyzed in this research. The simulated and measured results indicate that a RGC system attached with a TCC can improve its speed and torque fluctuation at the designed speed significantly. However, this compensation effect is quite sensitive to the driving speed. On the contrary, the compensation effect introduced by using an idle wheel is not so sensitive to the speed as the TCC does. The low cost and easy design are also the favorable factors for using an idle wheel to instead of an expensive TCC device.
3

Design of Rotary Tables Using Roller Gear Cam Mechanisms

Tsai, Payee 27 May 2000 (has links)
Rotary tables are generally regarded as the forth axis of machining tools. Traditionally, gear sets are used as reducers in the rotary tables. In order to improve the positioning accuracy, load and efficiency of rotary tables, a rotary table which applies the roller gear cam reducer is proposed. From the deduction of the theory, applications of roller gear cam reducers in the industries can be achieved. This thesis is focused on developing the procedure as follows: Firstly, the type of roller gear cam reducer and design parameters are identified. Secondly, the mechanical characteristics of the device are analyzed. Finally, a rotary table is designed and implemented to investigate the performance of the of the roller gear cam rotary table.
4

A Study of the Torque Compensating Phase on the Positioning Accuracy of Indexing Tables

Ho, Sheng-Ying 05 July 2001 (has links)
Recently, many industries pursue the goal of automatic high-speed assembly and manufacturing. So how to meet the requirement of high-precision and high-speed automatic assembly equipment is an important issue. In automatic assembly equipment, the high-speed indexing devices have been widely used because of their features of high precision, no backlash, and compactness. With increasing operating speeds, the problems of shortage of motor power, poor indexing accuracy, vibration, and noise shall be solved. The torque compensation mechanism that is to be developed here is applied to keep motors operating at constant speeds by compensating the required torque. In previous researches, the researchers all devote to study torque compensation based on synchronous time chart. In this paper, it is aimed at compensation of the time control chart according the point of view of energy and the system model is built to simulate dynamic response of the system. Through the results of simulation and experiment, we will discover the relations between the compensation time chart and parameters about the high-speed indexing devices. It is expected to improve the precision of indexing devices according to those effective compensation time control charts.

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