Control system for a power steering device
First Claim
1. A control system for a power steering device having a steering force transmitting mechanism for transmitting manual steering force applied to a steering wheel to at least one steerable wheel, said steering force transmitting mechanism including a fluid supply and a power cylinder coupled to the fluid supply for imparting assisting force thereto, said control system comprising:
- a solenoid valve fluidally coupled between said power cylinder and said fluid supply, including,(i) a valve chamber and a spool slidably received in said valve chamber without any mechanical connection with said steering force transmitting mechanism for controlling the supply and exhaust of pressurized fluid to and from said power cylinder, and(ii) a pair of solenoids for controlling the sliding movement of said spool;
first and second detecting means for detecting the rotary angular position of said steering wheel and the vehicle driving speed so as to output rotary angular position data and driving speed data, respectively;
memory means for storing a plurality of first control values respectively associated with various vehicle driving speeds; and
control circuit means connected to said pair of said solenoids and said memory means and responsive to said rotary angular position data and said driving speed data respectively supplied from said first and second detecting means for selecting one of said pair of said solenoids and one of said plurality of said first control values and for applying to said selected one of said first pair of said solenoids an electric current having a value corresponding to said selected one of said plurality of said first control values,whereby said assisting force generated by said power cylinder is controlled in correspondence to said detected vehicle driving speed.
1 Assignment
0 Petitions
Accused Products
Abstract
A control system for a power steering device of a vehicle, wherein the rotational angular position of a steering wheel, the vehicle driving speed and the steering torque applied to the steering wheel are detected and processed by a digital computer. The computer selects one of plural control values stored in a memory device based upon the detected steering torque and the detected vehicle speed and outputs the selected one of the control values along with solenoid selection data which is determined based upon the detected rotary angular position data. An electric current having a value corresponding to the selected one of the control values is applied from a solenoid drive circuit to one of a pair of solenoids, so that a four-way open center type solenoid valve having the solenoids controls the supply and exhaust of pressurized fluid to and away from a power cylinder of the power steering device in accordance with the detected vehicle driving speed and the detected steering torque.
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Citations
4 Claims
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1. A control system for a power steering device having a steering force transmitting mechanism for transmitting manual steering force applied to a steering wheel to at least one steerable wheel, said steering force transmitting mechanism including a fluid supply and a power cylinder coupled to the fluid supply for imparting assisting force thereto, said control system comprising:
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a solenoid valve fluidally coupled between said power cylinder and said fluid supply, including, (i) a valve chamber and a spool slidably received in said valve chamber without any mechanical connection with said steering force transmitting mechanism for controlling the supply and exhaust of pressurized fluid to and from said power cylinder, and (ii) a pair of solenoids for controlling the sliding movement of said spool; first and second detecting means for detecting the rotary angular position of said steering wheel and the vehicle driving speed so as to output rotary angular position data and driving speed data, respectively; memory means for storing a plurality of first control values respectively associated with various vehicle driving speeds; and control circuit means connected to said pair of said solenoids and said memory means and responsive to said rotary angular position data and said driving speed data respectively supplied from said first and second detecting means for selecting one of said pair of said solenoids and one of said plurality of said first control values and for applying to said selected one of said first pair of said solenoids an electric current having a value corresponding to said selected one of said plurality of said first control values, whereby said assisting force generated by said power cylinder is controlled in correspondence to said detected vehicle driving speed. - View Dependent Claims (2, 3, 4)
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Specification