The paper presents a computer-based guide of the effect of layout and loading (tension and
torque) on the timing belt life and uses it to show the sensitivity of life to changed conditions in an
automotive camshaft drive. The predictions are in line with experience. The guide requires belt property
information, such as the tooth and tension member stiffness, the friction coefficient between the belt lands
and pulleys and the pitch difference from the pulley, in order to calculate the tooth deflections caused by
the belt loadings on the various pulleys in the layout. It also requires information on how the belt life
depends on the tooth deflections. Experimental data are presented on the life±deflection relations of a
commercial automotive timing belt tested between 100 and 140 8C, although the bulk of the data has been
obtained at 120 8C. Four different life laws have been found, depending on whether the failure-initiating
deflection occurred on a driver or a driven pulley, and whether at entry to or exit from the pulley.
Theoretical analysis of the tooth loading in the partial meshing state shows that, in three cases out of the
four, the different life±deflection laws transform to a single relation between the life and the tooth root
strain. The exception is failure caused by driven entry conditions; work is continuing to understand better
the causes of failure in this circumstance
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/2376 |
| Date | January 1998 |
| Creators | Childs, T.H.C., Dalgarno, K.W., Day, Andrew J., Moore, R.B. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Published version |
| Rights | © 1998 IMechE. Reproduced in accordance with the publisher's self-archiving policy. |
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