An investigation of torque limiting mechanisms for an outboard boat motor
Maljaars, Brad (author) Siklosi, Michael (author) Niet, Taco (thesis advisor) British Columbia Institute of Technology Mechanical Engineering (Degree granting institution)
Research paper/project
http://rightsstatements.org/vocab/InC/1.0/ © Brad Maljaars, Michael Siklosi, 2019. All rights reserved. No part of this work covered by the copyright heron may be reproduced or used in any form or by any means – graphics, electronic, or mechanical including photocopying, taping, or information storage and retrieval systems – without written permission of the author.http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
British Columbia Institute of Technology
2019
85 pages
The Honda BF8A motor uses a shear pin as the torque limiting mechanism by which the engine is protected in the event that the propeller is prevented from rotating due to the surrounding environment. An investigation of four novel mechanisms is conducted as an alternative to the shear pin. A friction clutch requiring magnet forces to produce the normal forces pushing together a friction material face and bronze face together is the first concept studied. Theoretical calculations and experiments were conducted verifying the concept could not be implemented. The second concept is metal-metal mating surfaces to transfer torque. An experiment was designed to test the feasibility of the concept but the idea was abandoned after manufacturing of the metal faces proved impractical. The third concept is rubber-rubber mating surfaces. A relation was derived relating the release torque to the force holding the faces together. A test apparatus was designed and manufactured producing results that showed the general theory was inadequate to describe the mechanism. The fourth concept used centrifugal forces of a spinning mechanism to engage the propeller. A theoretical analysis was conducted. However, a variety of considerations showed the idea to be impractical.
MECH 8290
electronic
Bachelor of Mechanical Engineering
