Harmonic drives
AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
InventorDerek Keith Brighton
Life of this patent
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Abstract
A harmonic drive in which the teeth on either or both of the flexspline and internal spline have a modified involute profile with a small contact angle when fully meshed, and considerable tip relief. The former preferably comprises three discs in line on an input shaft which is cranked to a small eccentricity, the center disc eccentricity being diametrically opposite that of the outside pair. Pressure lubricated plain bearings are advantageously used.
Claims12
A harmonic drive of the type comprising an input shaft, a former mounted on the shaft, a flexspline surrounding the former and an internal spline surrounding the flexspline, wherein the teeth on at least one of the flexspline and the internal spline have a modified involute profile with a small contact angle when fully meshed and considerable tip relief.
A harmonic drive comprising an input shaft, a former mounted on the shaft, a flexspline surrounding the former, and an internal spline surrounding the flexspline, there being a few less teeth on the flexspline than on the internal spline and the flexspline being arranged to be cyclically deformable by the former so that teeth in a protruded portion of the flexspline can mesh with teeth on the internal spline, the teeth on at least one of the splines having a modified involute profile with a contact angle when fully meshed of between 10.degree. and 15.degree. and a flank to tip profile of substantially constant radius extending between the corresponding edges of that part of each flank of the tooth which in use contacts with maximum working pressure.
Dependencies are inferred from the claim text.