Patent ID: 7004281
Filing Date: 2006-02-28
Classification: B62D

Abstract:
1. A transmission ratio adjustable steering apparatus, comprising: an input shaft connected to a steering wheel, an output shaft connected to a steerable wheel, a transmission ratio changing mechanism for changing a ratio of a rotational angle of said output shaft to a rotational angle of said input shaft, a coupling member shiftable between a locked position and an unlocked position, so that said input shaft and said output shaft integrally rotate when said coupling member is in said locked position, while said input shaft and said output shaft are released from a coupling condition and brought into an unlocked condition where the transmission ratio of the rotational angle of said output shaft to the rotational angle of said input shaft is adjustable by said transmission ratio changing mechanism when said coupling member is in said unlocked position, a resilient member for resiliently urging said coupling member toward said locked position, a solenoid for holding said coupling member at said unlocked position against a resilient force of said resilient member, and a solenoid drive control apparatus for applying a drive voltage to said solenoid to hold said coupling member positioned at said unlocked position and reducing said drive voltage through a voltage attenuation process before said coupling member finally reaches said locked position, so that during said voltage attenuation process said solenoid produces an electromagnetic force yielding to the resilient force of said resilient member and decreasing a shifting speed of said coupling member on the way to said locked position.