PUMP FOR POWER STEERING

PURPOSE:To ease controlling pump discharge by varying the quantity of working oil per stroke of a plunger, which is discharged into a discharge passage, by rotating a plunger in such a manner that the force required to vary the pump discharge may be reduced. CONSTITUTION:When the pump discharge should be varied, for example, reduced, a cap 41 is loosened so that a control rod 26 may slide via both a spring 42 and a piston 40. As a result, a plunger 19 rotate-moves via both a pin 27 and a rotate- moving member 25, and when the plunger 19 is, for example, at the lower dead point, the distance between the fore end of the plunger 19 and an escape passage 29 increases. Accordingly, the escape passage 29 is closed, permitting the working oil to be discharged, only after the plunger 19 has traveled from the lower dead point a longer distance than before, which allows less working oil than before to be discharged into a discharge passage 31. When the pump discharge should be increased, the cap 41 is moved in the opposite direction with the above, increasing the energizing force of the spring so that the plunger 19 may be kept at the maximum discharge position.