Power steering system

#1. Field of the Invention

#This invention relates to a power steering system including a flow control valve for the prevention of energy loss.

#2. Description of Related Art

#FIG. 1 is a diagram for illustrating a control system of a controller C in a first embodiment.

#FIG. 2 is a diagram for illustrating a control system of a controller C in a second embodiment.

#FIG. 3 is a general diagram illustrating a power steering system in the prior art.

#FIG. 1 illustrates a control system of a controller C of a first embodiment according to the present invention. In the case of the first embodiment, the power steering system has the same configuration including the flow control valve V, the power cylinder 8, the steering valve 9 and so on illustrated in FIG. 3, exclusive of the controller C, as that of the prior art example which has been described earlier in FIG. 3, and the main description will now be given of the control system of the controller C.

#As illustrated in FIG. 1, the controller C stores a table of basic current instruction values I1 corresponding to the combination of steering angles and steering angular velocities. The table shows a list of values resulting from the additions of current instruction values Iθ based on the steering angles and current instruction values Iω based on the steering angular velocities. Upon reception of the input of a steering angle detected by the steering angle sensor 14, the controller C finds from the table a basic current instruction value Id corresponding to the detected steering angle and a steering angular velocity obtained by differentiating the steering angle.

#Whenever the prior art controller C receives the input of the steering angle from the steering angle sensor 14, it performs the addition of the steering angle signal Iθ based on the steering angle and the steering angular velocity signal Iω based on the steering angular velocity. However, the first embodiment does not perform such an addition but selects an applicable basic current instruction value I1 from the table. Consequently, the processing speed of the controller is increased by a reduction in the time required for the computation processing.