Wear of Unlubricated Plastic Gears - Determination of Characteristics and Dimensioning
Processing via injection moulding and the possibility of dry-running permanently make plastic gears enter new fields of application. Dry-running is required in a number of application areas, such as medical technology and desirable in many others. Some reasons are that lubricants can bind abrasive particles, influence the environment and are temperature-sensitive. This doctoral thesis presents results of conducted trials with steel/polymer (polyacetal and polyester) gearings that indicate that conventional sizing often does not tap the full potential of a gear.
Due to the absence of standardized wear measurement and a corresponding design technique, a dominant failure mode, the continuous wear, is unaccounted. In this doctoral thesis a method for determination and wear prediction was developed. A design strategy has been generated which takes account of the failure mechanisms of dry-running plastic gears and of the hitherto neglected failure criterion of tooth-flank wear. Necessary test and measuring equipment was designed and built up. Wear is an output from a complex tribological system, whose inputs are weighted to reflect their relevance. Correlation of the results for wear under different load conditions shows that the principal variables are the specific sliding, the number of cycles and the line load.
Therefore these variables are reflected in the proposed wear characteristic. The outcome is a powerful method that enables designers to economically design and check plastic gears raising expectations of a substantial increase in attainable power density. This enables engineers to exploit an up to now unused substantial portion of a gears’ potential.Lesen Sie die deutsche Zusammenfassung auf Kunststoffe.de
Sliding wear, polymers, gears, wear modelling, wear testing
Institute / chair: Technische Fakultät der Universität Erlangen-Nürnberg
Technical consultant for expert services: Prof. Dr.-Ing. Ernst Schmachtenberg (Betreuer), Prof. Dr.-Ing. Johannes Wortberg, Prof. Dr.-Ing. Dr. h.c. Gottfried W. Ehrenstein
Publication year: 2008
Provider: Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK) / Kunststoffe.de
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In cooperation with the Wissenschaftlicher Arbeitskreis Kunststofftechnik (WAK), we provide free access to current dissertations in the field of plastics technology.