Planetengetriebe

摘要

Planetary gear apparatus comprises a ring gear 10 having teeth 12 in the form of pins 14 which engage with epitrochoid shaped gear teeth 22 on gear 20. Teeth 22 have deddendum and addendum portions 26, 27 that are closer to centre axis O20 of the gear 20 than a theoretical epitrochoid curve La. This provides a modified profile having a clearance so that when torque is applied to the gear 10 the portions 26, 27 do not contact teeth 12. Tooth engaging portions 25 have an epitrochoid tooth surface Fa, extending on the theoretical epitrochoid curve La, which continually contact teeth 12 even when no torque is applied to ring gear 10. The centre axes O10 and O20 are offset by an amount eo so that the gear 20 has an orbital motion within ring gear 10.