HYDRAULIC CONTROL VALVE FOR POWER STEERING DEVICE

PROBLEM TO BE SOLVED: To stably provide an assist force characteristic suited to a traveling condition without needing any additional structures in input and output shafts or in the peripheries thereof. SOLUTION: An outer cylinder 7 is provided so as to be externally seen in a part of a torsion bar 4 for coaxially connecting input and output shafts 2 and 3 to each other. One side of the outer cylinder 7 is pressed into a part of a connecting part 4b for connection with the input shaft 2 and regulated in at least a peripheral direction by providing a knock pin 70. The other side having specified elasticity in a diameter direction is placed to face a slight large diameter engaging part 4c in the midway of the torsion bar 4, and grasping balls 8 and 8 held in corresponding positions are engaged with recessed parts provided in the midway of a locus line 90 provided in the outer periphery of the engaging part 4c. Thus, during small-turn steering in which steering torque applied to the input shaft 2 is small, twisting of the torsion bar 4 is produced by using a portion excluding the fitting part of the outer cylinder 7 as an effective length (=L0 ), and during large-turn steering in which steering torque exceeds a specified level, grasping by the grasping balls 8 and 8 is released, its near full length is produced as an effective length (=L1 ), and thus a change is made in an assist force characteristic obtained according to a relative angle displacement between the input and output shafts 2 and 3.