| 摘要 |
<p>An improved a power steering apparatus includes a fluid motor which is connected with a steerable vehicle wheel by a rack gear. The fluid motor has a piston with a relatively large head end surface area and a relatively small rod end surface area. In order to compensate for the difference in the head and rod end surface areas, actuation of a steering control valve assembly is resisted with a greater force when fluid pressure is being directed toward the head end surface area than when fluid pressure is being directed toward the rod end surface area. The force resisting actuation of the valve assembly is exerted by a spring assembly which includes a torsion bar disposed within a torsion tube. When the valve assembly is actuated to direct fluid pressure toward the relatively large head end surface area of the piston, both the torsion tube and bar are deflected. When the valve assembly is actuated to direct fluid pressure toward the relatively small rod end surface area, only the torsion bar is deflected.</p> |
