Patent ID: 7775932

Claim:
A manual helical planetary transmission comprising a housing, a sun gear, a planet carrier with helical planet gears and an axially displaceable annulus gear which can be selectively coupled to the housing or to one of two other members of the planetary transmission, the planetary transmission further comprising: first coupling teeth arranged at both sides all around end faces of the annulus gear, the first coupling teeth being axially direction and having a sawtooth shape in a section normal to an axis of the annulus gear, and have a gently rising first flank; second coupling teeth arranged at the housing and at one of the two other members of the planetary transmission, the second coupling teeth being axially directed and having a sawtooth shape in a section normal to the axis of the housing, and have a gently rising first flank fit into the gaps formed by the first coupling teeth; wherein, in a respective shift ratio, peripheral forces acting on the annulus gear press the gently rising first flanks of the first coupling teeth against the gently rising first flanks of the second coupling teeth at the housing or at the planet carrier and fix the annulus gear in an engaged position.