EPS System Description - Steering Gearbox

Overview

	The steering gearbox is dual pinion type, which includes two pinions that are engaged with steering rack.
	The EPS motor and EPS control unit are gathered into one unit, and are installed on the assist pinion shaft side.
	The torque sensor which detects steering torque is installed on the manual pinion shaft side.
	The steering rack adopts VGR (Variable Gear Ratio).

Construction

The assist pinion shaft transmits the EPS motor power to the steering rack. The EPS motor power is transmitted to the worm wheel by the worm gear. The assist pinion shaft moves the steering rack with the EPS motor power that is increased and transmitted by the worm wheel.
The manual pinion shaft transmits the steering torque from the steering wheel to the steering rack. The steering torque is transmitted from the steering column shaft to the input shaft, and the manual pinion shaft connecting with the input shaft by the torsion bar moves the steering rack.

NOTE: Do not adjust the rack guide of the steering gearbox.

VGR (Variable Gear Ratio)

The VGR is applied to the manual pinion shaft side of the steering rack. The normal gear ratio is applied to the near the straight ahead position of the steering rack for smooth start of steering operation. The quick gear ratio is applied for a large steering angle, which reduces lock-to-lock steering.