Abstract: In order to realize cost reduction in a gear pump apparatus by reducing form accuracy of a gear while securing pump performance, a running-in coating is provided on a tooth sliding contact portion when forming a confinement area in at least one of gears of the gear pump apparatus. By this feature, the running-in coating is gradually worn away and deformed according to rotary drive of the pump, and thus it is possible to obtain an optimal gear form in meshing combinations of the gears. Further, it is possible to reduce leakage inside the pump to secure the pump performance even if the form accuracy of the gear is reduced for the sake of the cost reduction.

Abstract: In order to realize cost reduction in a gear pump apparatus by reducing form accuracy of a gear while securing pump performance, a running-in coating is provided on a tooth sliding contact portion when forming a confinement area in at least one of gears of the gear pump apparatus. By this feature, the running-in coating is gradually worn away and deformed according to rotary drive of the pump, and thus it is possible to obtain an optimal gear form in meshing combinations of the gears. Further, it is possible to reduce leakage inside the pump to secure the pump performance even if the form accuracy of the gear is reduced for the sake of the cost reduction.

Abstract: In a power-cylinder equipped power steering device, under a first condition where a first directional control valve disposed in a first pressure line receives fluid pressure supplied into a second pressure line by a reversible pump, the first directional control valve intercommunicates a reservoir and a first-pressure-line downstream passage section, and blocks fluid communication of the first-pressure-line upstream and downstream passage sections. Under a second condition where a second directional control valve receives fluid pressure supplied into the first pressure line by the pump, the first directional control valve intercommunicates the first-pressure-line upstream and downstream passage sections. Under the second condition, the second directional control valve intercommunicates the reservoir and the second-pressure-line downstream passage section, and blocks fluid communication of the second-pressure-line upstream and downstream passage sections.