CH10齿轮传动1.ppt

* * * * * * * * * * * * The inspiration for this project came from Dr. Aaron Hoover’s original M?bius Gear design. While we used the same concept and general geometry, we have made a number of improvements including more selective compliance and adjusting the width and diameter of the M?bius gear. These changes eliminated many of the problems observed with the original model by keeping all gears sufficiently aligned with each other. The M?bius Gear has three major components, which we have designated the inner gear, the outer gear, and the planet gears. The outer gear is rigid and stationary and provides the structure for the moving components. The inner gear is a semi-compliant M?bius strip with teeth on its one face. It is made from silicone molded over a rigid metal wire, which allows it to keep its neutral axis ciruclar but still twist as it rotates through the outer gear. The planet gears are what provide the interface between the inner and outer gears and make sure that the inner gear twists and rolls correctly along the outer gear. Our most crucial design insight occurred when we realized the inner gear needed to be rigidly fixed along its neutral axis. If this was not the case, pulling on the inner gear caused the planets and the inner gear to begin slipping out of the outer gear. Based on our experience from several iterations, we decided that the best way to avoid this would be to embed a metal wire inside the inner gear. We decided to use a relatively soft 1/32 galvanized steel wire, which was easy to bend into the correct size circle. This prevented any kind of permanent spring loading on the strip. Since the inner gear still needs to be able to twist, though, instead of embedding the wire directly into the silicone, we embedded a small plastic tube first. The wire, pre-formed into a circular shape, was then inserted into the inner gear. We found that this method significantly improved functionality by reducing friction, eliminating lateral gear slippage