US 2006/0076181 A1 · Electric power-steering device

Abstract

An electric power steering apparatus includes a reduction gear mechanism (17) for reducing the rotation speed of an output shaft (16) of an electric motor (15). The reduction gear mechanism (17) comprises an inscribed gear (39) rotatable interlockingly with the output shaft (16), and a circumscribed gear (40) in which the inscribed gear (39) is inscribed. An endless belt connects a driving pulley (41) integrally rotatable with the circumscribed gear (40) and a driven pulley (42) disposed so as to surround a steerable shaft. By heightening the reduction gear ratio by the speed reduction using the inscribed gear (39) and the circumscribed gear (40), the reduction gear mechanism (17) as a whole can achieve a high reduction gear ratio without making the diameter of the driving pulley (41) very small.

Claims17

Dependent claims

An electric power steering apparatus comprising:

an electric motor for generating steering assist force;
a reduction gear mechanism for reducing a rotation speed of an output shaft of the electric motor;
and
a conversion mechanism for converting the output rotation of the reduction gear mechanism into an axial movement of a steerable shaft extending in a transverse direction of a vehicle,
the reduction mechanism comprising:
an inscribed gear having external teeth and being rotatable interlockingly with the output shaft of the electric motor;
a circumscribed gear having internal teeth in which the inscribe gear is inscribed;
a driving pulley integrally rotatable with the circumscribed gear;
a driven pulley disposed so as to surround the steerable shaft;
and
an endless belt for connecting the driving pulley and the driven pulley.

8 more elements

Dependencies are inferred from the claim text.

Electric power-steering device

Life of this patent

Electric power-steering device

Life of this patent

Abstract

Claims17