Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates a control valve for selectively controlling the flow of hydraulic fluid to input ports of a power output transducer in response to a mechanically applied input signal. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer. A pressure regulating apparatus is provided for selectively regulating the supply pressure to a value that is nominally equal to the absolute value of the load pressure summed with a preselected supplemental pressure value across the regulating apparatus.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates an open-center control valve for selectively controlling the differential pressure applied to and the differential flow between input ports of a power output transducer in response to a mechanically applied rotational inputs. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer.

Abstract: A preload mechanism for use in a rotary control valve is disclosed. The preload mechanism mechanically interlocks input and output members of the control valve to inhibit relative rotation therebetween when steering torque applied to the input member is below a predetermined preload level. The preload mechanism includes a tension spring ring having at least one pair of elongated slots. Pins secured to each of the input and output members project through and are retained in the slots in an over-constrained manner whereby the preload force is bi-directionally exerted on both of the pins.

Abstract: A preload mechanism for use in a rotary control valve is disclosed. The preload mechanism mechanically interlocks input and output members of the control valve to inhibit relative rotation therebetween when steering torque applied to the input member is below a predetermined preload level. The preload mechanism includes a tension spring ring having at least one pair of elongated slots. Pins secured to each of the input and output members project through and are retained in the slots in an over-constrained manner whereby the preload force is bi-directionally exerted on both of the pins.

Abstract: An electronically controlled power steering system for motor vehicles is disclosed for steering dirigible wheels in response to an input torque applied to a steering wheel. The power steering system includes a mechanical steering gear mechanism coupled to the steering wheel for generating a mechanically derived steering force in response to the input torque. A power cylinder is coupled to the mechanical steering gear mechanism for producing a hydraulically derived steering force which augments the mechanically derived steering force. A control valve is provided which is in fluid communication with the power cylinder for generating differential pressure applied to the power cylinder. A first signal is generated which is indicative of the input torque applied to the steering wheel. A signal processing unit generates an output signal in response to the first signal.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates an open-center control valve for selectively controlling the differential pressure applied to and the differential flow between input ports of a power output transducer in response to a mechanically applied rotational inputs. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer.

Abstract: The present invention is directed to providing an improved control valve having input and return flow passages that are hydraulically-balanced by virtue of each having a similar flow configuration for fluid flow therethrough. The input and return flow passages are formed to define input and return flow control orifices, respectively, configured for minimizing the possibility of the jet flow issuing from either input or return flow control orifices from impinging upon a surface in juxtaposition to the flow control orifice itself. Thus, the possibility of partial "flow back" into the flow control orifice is eliminated which, in turn, also prevents any significant reduction in the flow control orifice area.

Abstract: The present invention is directed to a vehicular power steering system having an "open-center" control valve that has substantially zero hydraulic flow gain at zero input deflection angle and yet has minimal control orifice area. Improved valving arrangement is desirable in that it leads to rapid restoration of hydraulic flow gain at relatively small input deflection angles. The improved valving arrangement includes small transverse leakage slots formed in a valve spool that are positioned in parallel with either input or return flow distribution slots. The leakage slots are configured to form parasitic flow orifices which fluidically interconnect the output slots formed in the valve sleeve and which communicate with the fluid chambers formed on opposite sides of the piston in the power cylinder. Accordingly, a selectively variable leakage path is provided across the power cylinder.

Abstract: An improved open-center improved valving sub-assembly of the type used for power steering systems for motor vehicles is disclosed. In particular, the improved open-center improved valving sub-assembly has a valve spool member with first and second sets of input slots and first and second sets of return slots, and a valve sleeve member with output slots and diversionary slots wherein only the output slots are coupled to a power cylinder member of a host power steering system. The output slots are linked fluidically to the first sets of input and return slots by input and return flow control orifices each comprising overlapping tangentially disposed areas therebetween. The diversionary slots are linked fluidically to the second sets of input and return slots by input and return flow selective control orifices each comprising overlapping tangentially disposed areas therebetween.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates an improved closed-center control valve for selectively controlling the differential pressure applied to the input ports of a power output transducer and the differential flow therebetween in response to a mechanically applied rotational input. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The improved closed-center control valve is a modified rotary valve wherein parasitic leakage slots are formed for providing a leakage flow pathway through the control valve between the input ports of the power output transducer.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates a control valve for selectively controlling the flow of hydraulic fluid to input ports of a power output transducer. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer. A pressure regulating apparatus is provided for selectively regulating the supply pressure to a value that is nominally equal to the absolute value of the load pressure summed with a preselected supplemental pressure value across the regulating apparatus.

Abstract: A tachometer particularly adapted for operation as a rotational velocity feedback transducer is provided. First and second proximity detectors are used to monitor orthogonal positions of an irregular surface portion of a rotating shaft and provide x and y signals that are substantially in quadrature. The x and y signals are differentiated with respect to time to provide differential signals that are representative of dx/dt and dy/dt, respectively. Signals representative of products x dy/dt and y dx/dt are generated from the x signal and the differential signal dy/dt, and the y signal and the differential signal dx/dt, respectively. A signal representative of algebraic sum x dy/dt--y dx/dt is generated from the signals representative of products x dy/dt and y dx/dt. A signal representative of quotient of (x dy/dt-y dx/dt) divided by the displacement r.sup.

Abstract: An improved power steering system in which the ratio of output force to input torque is variable. The power steering system includes an input shaft as well as an inner valve member and an outer valve member which are able to generate hydraulic fluid pressure in response to the input torque. A rack assembly is provided for generating the output force in response to the hydraulic fluid pressure generated in response to the input torque. The improved power steering system further includes a pinion shaft which mechanically communicates with the rack assembly and provides a reference position for the improved power steering system. A torsion bar compliantly couples the inner valve member to the pinion shaft, a twist angle of the torsion bar serving to provide a position error signal to the improved power steering system. Finally, a torsion bar extension compliantly couples the torsion bar to the input shaft.

Abstract: An improved power steering system for motor vehicles of the type used for steering dirigible wheels is disclosed. In particular, the improved system is a rotary valve equipped power steering system in which the steering wheel is coupled to the rotary control valve via a coupling device having a rotational stiffness characteristic that is less than the rotational stiffness characteristic associated with the rotary valve itself.

Abstract: A tachometer particularly adapted for operation as a rotational velocity feedback transducer is provided. First and second proximity detectors are used to monitor orthogonal positions of an irregular surface portion of a rotating shaft and provide x and y signals that are substantially in quadrature. The x and y signals are differentiated with respect to time to provide differential signals that are representative of dx/dt and dy/dt, respectively. Signals representative of products x dy/dt and y dx/dt are generated from the x signal and the differential signal dy/dt, and the y signal and the differential signal dx/dt, respectively. A signal representative of algebraic sum x dy/dt-y dx/dt is generated from the signals representative of products x dy/dt and y dx/dt. A signal representative of quotient of (x dy/dt-y dx/dt) divided by the square of the displacement r.sup.

Abstract: A steering assembly for multiplying steering torque and motion applied from a steering wheel of a vehicle by fixed and selectively varying ratios, respectively. The applied steering torque and motion are coupled via an input shaft to a sun gear of a planetary gear set. Supplementary torque and steering motion are generated by a servo motor which is coupled to a ring gear of the planetary gear set via an irreversible differential planetary gear set. Rotational motion of the input shaft is determined and rotational motion of the servo motor is controlled as a selected function of the rotational motion of the input shaft. Actual rotational motion of the servo motor is measured and additional rotational motion of the servo motor is terminated if the actual rotational motion of the servo motor does not substantially match the selected rotational motion. A set of planetary gears mounted in a planetary carrier receives combined output torque and rotational motion from both the sun and ring gears.

Abstract: A valve for controlling a double-acting utilization device includes inner and outer valve members where the outer valve member has pressure slots with first and second lateral edges, respectively, and the inner valve member includes first and second lands with third and fourth lateral edges, respectively. The first and third lateral edges form input orifices and second and fourth lateral edges form return orifices. The effective radial positions of the input and return orifices are chosen to generate reaction torque within the valve itself. Drive torque and position are applied to the outer valve member and feedback torque and position are communicated to the inner valve member via a torsion bar which is coupled to an output member of the double-acting utilization device.