Steering-shaft-rotation-angle detection device

摘要

A steering-shaft-rotation-angle detection device that detects a rotation angle of a steering shaft that is rotated by operation of a steering wheel, includes an electric motor that assists steering of the steering wheel by a driver, a speed reduction mechanism that reduces speed of rotation of the electric motor and transmits the rotation to the steering shaft, a rotating body that is attached to a rotation shaft of the electric motor, a signal output unit that outputs a signal in accordance with rotation of the rotating body, and a controller that calculates a rotation angle of the rotating body on the basis of the output signal from the signal output unit and calculates, on the basis of this rotation angle and a speed reduction ratio of the speed reduction mechanism, a rotation angle of the steering shaft.

主权项

1. A steering-shaft-rotation-angle detection device for detecting a rotation angle of a steering shaft that is rotated by operation of a steering wheel, the steering-shaft-rotation-angle detection device comprising:
an electric motor that assists steering of the steering wheel by a driver; a speed reduction mechanism that reduces speed of rotation of the electric motor and transmits the rotation to the steering shaft; a rotating body that is attached to a rotation shaft of the electric motor; a signal output unit that outputs a signal in accordance with rotation of the rotating body; a reference-rotational-position detector that detects a reference rotational position of the steering shaft; and a controller that
sets a reference rotation angle of the steering shaft on the basis of an output signal from the reference-rotational-position detector,calculates an amount of change in the rotation angle of the steering shaft on the basis of a rotation angle of the rotating body, the rotation angle of the rotating body calculated on the basis of the output signal from the signal output unit and a speed reduction ratio of the speed reduction mechanism, andcalculates the rotation angle of the steering shaft by adding the calculated amount of change in the rotation angle to the reference rotation angle, wherein the reference-rotational-position detector outputs a pulse of signal for every rotation of the steering shaft, and the controller sets, on the basis of the received pulse of signal that is output from the reference-rotational-position detector for a first time from a neutral position of the steering shaft, a preset reference rotation angle corresponding to this pulse of signal as the reference rotation angle of the steering shaft.