TECHNICAL FIELD

The present invention relates to a power steering apparatus.

BACKGROUND TECHNOLOGY

As a power steering apparatus, for example, a power steering apparatus described in the following patent document 1 has been known.

In the power steering apparatus described in the patent document 1, by calculating a steering angle returning torque control amount from a steering angle gain map for determining a returning torque to an steering angle and a vehicle speed map for increasing and decreasing the returning torque in accordance with a vehicle speed, a handle return control is carried out.

PRIOR ART DOCUMENT

Patent Document

Patent Document 1: Japanese Patent Application Publication 2007-99053

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

In general, in the vicinity of a rack end in a low vehicle speed range, to compensate the shortage of a self-aligning torque, a steering angle returning torque control amount is set to be large. On the other hand, at the time of the stop of a vehicle, the steering angle retuning torque control amount is usually set to zero. In this case, the steering angle returning torque control amount is rapidly changed when the vehicle speed is changed from the low vehicle speed range to the vehicle stop, and there is the fear that an odd feeling of steering occurs.

However, in the power steering apparatus of the patent document 1, the rapid change of the steering angle returning torque control amount is not concerned, and there is the fear that the odd feeling occurs.

The present invention has been made in a consideration of such a current situation, and an object of the present invention is to provide a power steering apparatus which is capable of suppressing an odd feeling of steering in a low vehicle speed range.

Means for Solving the Problem

In the present invention, as one aspect thereof, the change rate of a steering angle returning torque command signal at the time when a vehicle speed increases from 0 km/h to a first predetermined vehicle speed is smaller than the change rate of the steering angle returning torque command signal at the time when the vehicle speed increases from the first predetermined vehicle speed to a second predetermined vehicle speed.

Effect of the Invention

According to the present invention, an odd feeling of steering in a low vehicle speed range can be suppressed.

