POWER ASSISTING DEVICE FOR VEHICLE AND POWER STEERING APPARATUS FOR VEHICLE HAVING THE SAME

摘要

PURPOSE: A power assistance of a vehicle and a power sub steering system including the same are provided to reduce the operating noise and increase the durability by reducing the load hanging on a motor through a power assistance. CONSTITUTION: A power assistance of a vehicle comprises a torque sensor(305), an electric control unit(310), a first power assistance(350) and a second power assistance(360). The torque sensor senses the rotating torque of a steering column(102). According to the input signal inputted from the torque sensor, the electric control unit transmits a steering assist power control signal. The first power assistance is moved according to the control signal inputted from the electric control unit. The first power assistance supports the steering force to the electric force while rotating the steering column at the forward or back direction. The second power assistance runs according to the control signal inputted from the electric control unit. The second power assistance supports the steering force to the fluid pressure of the working fluid while sliding the rack bar to the forward or back direction.