Abstract: A hydraulic power steering system having conventional relatively rotatable spool and valve body elements for flow regulation, and an integral electromagnetic mechanism which effectively varies the centering force between the spool and valve body to adjust the level of steering assist provided for a given operator steering input. The electromagnetic mechanism includes a rotary magnetic circuit and a stationary magnetic circuit. The rotary magnetic circuit comprises a pair of radially displaced magnetic pole pieces which rotate with the input shaft and a permanent magnet ring element which is disposed between the pole pieces and which rotates with the pinion shaft. The stationary magnetic circuit includes an annular exciting coil disposed in proximity to the rotary magnetic circuit. The exciting coil is energized so as to vary the valve body/spool centering force, and hence the driver steering effort, with vehicle speed.

Abstract: A drive system for artificial hearts and left-ventricular assist devices. The drive system includes one or more implantable pumps driven by external electromagnets. Each pump preferably includes an armature made of a permanent magnet material having a magnetic energy product of at least about 30.times.10.sup.6 Gauss Oersted, and coercivity of at least about 10 kOe.In one embodiment of the invention, a pair of pumps are provided, with each being coupled to a respective ventricle of an artificial heart. In a second embodiment, a pair of pumps is connected to a single left-ventricular assist device.Each pump is mounted to the pelvic bone in the vicinity of the iliac crest. Fluid communication between the pump and its associated ventricle or left-ventricular assist device is provided by a length of flexible tubing extending subcutaneously up from the pump. Means are provided to enable periodic reversal of internal system leakage, and to enable replenishment of fluid lost from the system.

Abstract: A hydraulically assisted power steering system subject to variance in steering effort due to temperature change is compensated to give consistent response at all temperatures. A hydraulic control valve is coupled to an electromagnetic device which controls the steering effort as a function of energization current. The current is adjusted in accordance with temperature to compensate for temperature changes. A microcomputer controller stores empirical data relating to the effect of temperature on steering effort and calculates the current adjustment necessary for any measured system temperature. In one embodiment, the temperature is not measured directly but is derived from the deviation of energization current from the theoretical desired current, which deviation is a function of temperature. The effect of voltage variations is also compensated for.

Abstract: A hydraulic power steering system having conventional relatively rotatable spool and valve body elements for flow regulation, a mechanically resilient element for generating a mechanical centering force in relation to the relative rotation of the spool and valve body to a centered condition, and an integral electromagnetic mechanism which variably assists the mechanical centering force to adjust the level of operator steering input required to produce a given level of power assist. The electromagnetic mechanism comprises an energized coil and a pair of flux conducting elements supported for rotation with the spool and valve body, respectively.

Abstract: An actuator has a permanent magnet ring with a plurality of radially magnetized poles rotatably positioned between a pair of toothed pole pieces with interdigitated teeth, an electromagnetic coil and pole elements coupling the coil flux to the pole pieces. The pole pieces may themselves be rotatable or stationary. The permanent magnet circuit attempts to move the magnet ring to a first position relative to the pole pieces, and the electromagnetic circuit, depending on the direction of current in the coil, torques the magnet in one direction or another toward stable positions on either side of the first position. The device is used as a two or three position actuator or as an actuator operating against an external force and seeking a position as a function of current.

Abstract: A homopolar actuator has a permanent magnet disk element rotatably positioned between a pair of toothed pole pieces with mutually offset teeth, an electromagnetic coil and pole elements coupling the coil flux to the pole pieces. The pole pieces may themselves be rotatable or stationary. The permanent magnet circuit attempts to center the disk element relative to the pole pieces, and the electromagnetic circuit, depending on the direction of current in the coil, either reinforces the centering action or overcomes the centering force to displace the elements from center position. The device is used as a two or three position actuator or as an actuator or magnetic spring operating against an external force and seeking a position as a function of current.

Abstract: A variable reluctance rotation sensor comprises a rotatable magnetic toothed wheel adjacent a fixed magnetic pickup assembly. The pickup assembly comprises a pair of permanent magnets, each with a similar pole adjacent the wheel and separated circumferentially by the arc between a tooth and a non-adjacent slot. A magnetic flux member with a coil joins the other poles of the magnets in series opposed relationship and extends in close proximity to the tooth wheel to establish separate flux loops for each magnet distributed along the coil. The flux loops are spatially determined by the teeth and slots between the permanent magnets, so that they fluctuate circumferentially and generate an electrical signal in the coil with wheel rotation by variation of the flux linkages to individual turns of the coil. The sensor thus uses spatial flux changes to produce a rotation signal at very low rotational speeds with a larger air gap than that of conventional sensors.

Abstract: A variable reluctance rotation sensor comprises a rotatable toothed wheel and a magnetic pickup assembly comprising a pair of permanent magnets each having a pair of poles with an opposite one of said poles adjacent the toothed wheel. The permanent magnets are separated from each other by an arc equal to the arc between two of the teeth and joined by a magnetic flux member with a multi-turn electrical coil wound thereon. The flux member establishes a common main flux loop through the first and second permament magnets but also extends close to the toothed wheel to further establish additional flux loops separately through each of the permanent magnets. Passage of alternating teeth and slots as the wheel rotates produces a spatial fluctuation in the additional flux loops between the magnets to vary the flux linkages with individual coil turns and increase the electrical signal in the coil over the signal level that would be produced by variations in air gap of the common flux loop alone.

Abstract: A hydraulic power steering system having conventional relatively rotatable spool and valve body elements for flow regulation, a mechanically resilient element for generating a mechanical centering force in relation to the relative rotation of the spool and valve body which tends to restore the spool and valve body to a centered condition, and an integral electromagnetic mechanism which variably opposes the mechanical centering force to adjust the level of operator steering input required to produce a given level of power assist. The electromagnetic mechanism comprises an energized coil and a pair of flux conducting elements supported for rotation with the spool and valve body, respectively. The flux conducting elements have interleaved teeth which are magnetically coupled to the coil to define a magnetic circuit having an inter-tooth working air gap which varies with the relative rotation of the spool and valve body.

Abstract: A hydraulic power steering system having conventional relatively rotatable spool and valve body elements for flow regulation, and an integral electromagnetic mechanism which effectively varies the centering force between the spool and valve body to adjust the level of steering assist provided for a given operator steering input. The electromagnetic mechanism comprises a rotary multipole permanent magnet supported for rotation with one of the spool and valve body elements, a rotary flux conducting element supported for rotation with the other of the spool and valve body elements, and a stationary exciting coil magnetically coupled thereto. The exciting coil is energized so as to produce a variable centering force between the spool and valve body with vehicle speed, which produces a corresponding variation in the driver steering effort.

Abstract: A hydraulic power steering system having conventional relatively rotatable spool and valve body elements for flow regulation, and an integral electromagnetic mechanism which effectively varies the centering force between the spool and valve body to adjust the level of steering assist provided for a given operator steering input. The electromagnetic mechanism includes a rotary magnetic circuit and a stationary magnetic circuit. The rotary magnetic circuit comprises a pair of axially displaced magnetic pole pieces which rotate with the pinion shaft and a permanent magnet disk element which is disposed between the pole pieces and which rotates with the input shaft. The stationary magnetic circuit includes an annular exciting coil disposed about the rotary magnetic circuit and ferromagnetic pole elements adjacent each of the rotary pole pieces. The exciting coil is energized so as to vary the valve body/spool centering force, and hence the driver steering effort, with vehicle speed.