Patent ID: 8942898
Filing Date: 2015-01-27
Classification: F16H,Y10T

Abstract:
1. A range switchover apparatus comprising: a motor; a range switchover mechanism for switching over a shift range among plural ranges by the motor as a drive source; an encoder for outputting a pulse signal in synchronism with rotation of the motor; a detent mechanism for holding the range switchover mechanism at each range position by allowing an engagement member to be fitted in a range holding recess, when the range switchover mechanism is switched over to each range position; and a control unit for controlling a switchover position of the range switchover mechanism by rotationally driving the motor based on an encoder count value indicative of a count value of the pulse signal of the encoder, wherein: the control unit is configured to perform a resting check, a range check and a reference position calculation, the resting check checks whether the range switchover mechanism is at rest with the engagement member being fitted in a bottom position of the range holding recess, by checking whether the range switchover mechanism is at rest with the drive force of the motor being released, the range check checks which one of the ranges the present shift range is, the reference position calculation calculates the encoder count value at a predetermined reference position based on the present shift range determined by the range check and the encoder count value, when the range switchover mechanism is determined to be at rest in the bottom position by the resting check; the range check checks the present shift range by performing hitting control, in which the motor is rotationally driven to a limit position of a movable range of the range switchover mechanism, and thereafter performing hitting return control, in which the motor is rotationally driven in reverse to return the range switchover mechanism from the limit position to the bottom position; and the resting check determines that the range switchover mechanism is at rest, when a change amount of the encoder count value is less than a predetermined value.