Power steering

A power steering, having a spool mounted in a main body and having one of ends facing one of pilot chambers communicating with a pump port at all times and the other end facing the other pilot chamber incorporating a spring, and having an orifice downstream from said one pilot chamber, and being configured to introduce pressure oil through the orifice into a steering valve for controlling a power cylinder, to control a movement position of the spool with a pressure balance between both the pilot chambers when pressure upstream from said orifice is set as a pilot pressure of said one pilot chamber and pressure downstream from said orifice is set as a pilot pressure of said other pilot chamber, and to distribute the pressure oil between a control flow rate QP for introducing the amount of discharge from a pump toward the steering valve and a return flow rate QT for making the pressure oil circulation-return toward a tank or the pump, said power steering wherein said orifice is a variable orifice controlling the degree of its opening in accordance with an excitation current I of a solenoid, comprising a controller provided for controlling the excitation current I of the solenoid for the variable orifice, and connected with a steering angle sensor, and the controller storing or calculating a steering angle θ and a steering angular velocity ω in accordance with a steering angle from the steering angle sensor, while calculating or storing a solenoid current instruction value Iθ in accordance with the steering angle θ and a solenoid current instruction value Iω in accordance with the steering angular velocity ω, and adding the solenoid current instruction values Iθ and Iω, and further adding the added value to a solenoid current instruction value IS for standby, and then controlling the excitation current I of the solenoid for the variable orifice based on said finally added instruction value.