| 摘要 |
A gearbox assembly (100) for an electric power assisted steering apparatus comprises a gearbox housing which houses a worm shaft (3) and a gear wheel (10), the worm shaft being supported relative to the housing (2) by a main bearing (5) at an end closest to the motor (4) and by a tail bearing (6) at an end furthest from the motor, and the gear wheel being supported by an output shaft (11) having at least one end that provides a take-off from the gearbox assembly, in which the main bearing and tail bearing are free to move relative to the housing through a limited range of motion that enables the worm shaft to pivot away from the wheel gear, the assembly further comprising: a first pivoting means (27) for the worm shaft main bearing which reacts the axial component of the worm shaft tooth load for a first direction of gearwheel torque but not for a second, opposing, direction of gearwheel torque and defines at least one first pivot point about which the main bearing pivots that is located on a pivot axis, a second pivoting means (28) for the worm shaft main bearing, positioned distal from the first pivoting means, which reacts the axial component of the worm shaft tooth load for the second direction of gearwheel torque but not the first direction of gearwheel torque and defines at least one second pivot point about which the main bearing pivots that is located on a second pivot axis, the second pivot point being spaced apart from the first pivot point. |
