Experimental determination of non load dependent losses for a dip lubricated worm type gear unit : gear churning and windage losses

Abstract

Environmental awareness and new legislation in today's market place has encouraged energy reduction activities. In light of this, demand for more efficient machinery has increased. One of the areas that contribute to power losses in most machines is gearbox. Detailed understanding of the reasons and sources of power losses within the gearbox are necessary if any efficiency improvements are to be made. Power losses within the gearbox can be divided into load dependent and nonload dependent losses. Load dependent losses consist of bearing frictional losses and gear mesh fi-ictional losses. On the other hand, non-load dependent losses consist of the oil seal losses, gear churning losses and bearing churning and windage losses. This research will only concentrate on the non-load dependent losses, particularly for a worm-wheel gearbox. The purpose of this research is to validate established mathematical models for estimating non-load dependent losses in a worm-wheel gearbox and compare the theoretical estimates to experimental results. A series of experiments were undertaken in a dip lubricated worm-wheel gearbox for this investigation. The experiments are run in a no load condition with 3 different speeds and 10 different oil levels. Data from the experiments are then analyzed and compared with the existing published equations. Finally, conclusion and recommendation are made based on the comparison between the existing published equations and analyzed data. The work presented is a continuafion from research done by Mr. Steven Bray (2001), Mr. David Reynolds (2002) and Mr. Evangelos Tsoudis (2002). An improvement on the test rig and testing methods have been done based on their recommendations, comments and findings in an attempt to get more accurate and reliable result. Additional oil levels also been introduced in order to understand the oil level effects on the power losses. Due to the time constraints, this research is done in collaboration with Mr. Darren Llyod Evans. The analysis of the non-load dependent losses is divided into gear losses and bearing and oil seal losses. This report will only focus on the gear losses.