Patent ID: 8935067
Filing Date: 2015-01-13
Classification: F16H

Abstract:
1. A shift-by-wire system for an automatic transmission of a vehicle, comprising: an electric motor unit that includes a rotor, wherein the rotor is rotated when the electric motor unit is energized; a manual shaft that is rotated by a drive force outputted from the electric motor unit upon rotation of the rotor; a detent plate that includes a plurality of recesses and is fixed to the manual shaft to rotate integrally with manual shaft; a detent spring that includes a limiting portion, wherein when the limiting portion is urged in a recessing direction of one of the plurality of recesses of the detent plate and is fitted into the one of the plurality of recesses of the detent plate, the rotation of the detent plate is limited to hold a shift range of the automatic transmission; a rotational position sensing device that directly or indirectly senses a rotational position of the manual shaft; a target range determination unit that determines a target range of the automatic transmission among a plurality of ranges based on a signal outputted from a shift range selecting device upon manipulation of the shift range selecting device by a driver of the vehicle; a range shift unit that shifts the shift range of the automatic transmission to the target range by rotating the rotor of the electric motor unit through energization of the electric motor unit to rotate the manual shaft, so that the rotational position of the manual shaft, which is sensed with the rotational position sensing device, reaches a target rotational position, which corresponds to the target range determined with the target range determination unit; a range determination unit that determines whether the rotational position of the manual shaft is in a predetermined extent of the target range based on the rotational position of the manual shaft that is rotated by the range shift unit; an actual range determination unit that senses an actual range of the automatic transmission by executing a range determination operation, which determines the actual range of the automatic transmission based on a result of determination of the range determination unit; and a determination prohibition unit that prohibits the actual range determination unit from executing the range determination operation throughout a range determination operation prohibiting period, which is a predetermined time period and starts from a time point at which the range shift unit starts rotation of the rotor of the electric motor unit toward the target rotational position.