Abstract: A differential angle sensor for measuring a differential angle between an input shaft and an output shaft includes a target assembly fixed to rotate with one of the shafts and a ring magnet with equidistantly spaced magnet segments fixed to rotate with the other one of the shafts. The target assembly includes four identical targets extending about the common axis parallel and axially spaced apart from one another, and each having a plurality of wedge-shaped teeth extending radially toward the ring magnet. A first magnetic field sensor is disposed between first and second targets for measuring a first magnetic field strength therebetween. A second magnetic field sensor is disposed between third and fourth targets for measuring a second magnetic field strength. The targets are all circumferentially offset relative to one another such that the magnetic field strengths each vary with the differential angle between the shafts and differently from one-another.

Abstract: A torque and angular sensor includes a differential angle sensor to precisely measure a differential angle between an input shaft and an output shaft and an angular position sensor to measure the angle of at least one of the shafts over a full angular range. The differential angle sensor measures an output rotation angle of an output target and an input rotation angle of an input target using changing voltages in taps on the input and output coils, which each carry an AC excitation current and which are each inductively coupled with teeth on targets fixed to rotate with one of the shafts. Input shaft rotation angle region is combined with the input angular position as a rotation angle composite. A raw torque angle is determined based on the difference between the input and output rotation angles. Rotational and Linear compensation provides a high-precision torque angle.

Abstract: A differential angle sensor for measuring a differential angle between an input shaft and an output shaft includes a target assembly fixed to rotate with one of the shafts and a ring magnet with equidistantly spaced magnet segments fixed to rotate with the other one of the shafts. The target assembly includes four identical targets extending about the common axis parallel and axially spaced apart from one another, and each having a plurality of wedge-shaped teeth extending radially toward the ring magnet. A first magnetic field sensor is disposed between first and second targets for measuring a first magnetic field strength therebetween. A second magnetic field sensor is disposed between third and fourth targets for measuring a second magnetic field strength. The targets are all circumferentially offset relative to one another such that the magnetic field strengths each vary with the differential angle between the shafts and differently from one-another.

Abstract: A torque and angular sensor includes a differential angle sensor to precisely measure a differential angle between an input shaft and an output shaft and an angular position sensor to measure the angle of at least one of the shafts over a full angular range. The differential angle sensor measures an output rotation angle of an output target and an input rotation angle of an input target using changing voltages in taps on the input and output coils, which each carry an AC excitation current and which are each inductively coupled with teeth on targets fixed to rotate with one of the shafts. Input shaft rotation angle region is combined with the input angular position as a rotation angle composite. A raw torque angle is determined based on the difference between the input and output rotation angles. Rotational and Linear compensation provides a high-precision torque angle.

Abstract: In one embodiment, a sensor assembly has a sensor housing forming a fluid chamber and a magnetostrictive wire that undergoes stress induced by fluid in the chamber. The wire defines opposed ends, each being associated with a respective terminal. Respective hermetic seals penetrate the housing and are coupled to the respective terminals.

Abstract: In one embodiment, a sensor assembly has a magnetostrictive (MS) element and a sensor housing defining at least one active wall. A sensor channel is disposed on a first side of the active wall, with the MS element being disposed in the sensor channel and closely received therein. A fluid is on a second side of the active wall, and the active wall is the wall through which stress from pressure of the fluid causes stress on the MS element. The sensor channel defines an axis parallel to the active wall, and the MS element is positioned adjacent the active wall by sliding the MS element into an end of the sensor channel in a direction parallel to the active wall.

Abstract: In one embodiment a sensor assembly has a magnetostrictive (MR) element in a sensor housing. The MR element has a sensing part engaged with a wire coil and a frusto-conical sealing part juxtaposed with a fluid the pressure of which is to be sensed.

Abstract: In one embodiment, a sensor assembly has a sensor housing forming a fluid chamber having a surface defining a normal axis. A magnetostrictive (MS) core that defines a central longitudinal axis is subjected to stress induced by pressurized fluid in the chamber. An excitation coil is coupled to the core to induce a magnetic flux therein. The central longitudinal axis of the core is coaxial with the axis normal to the fluid chamber surface.

Abstract: A system for measuring stress including a coilless sensor including at least one band of electrically conductive and magnetostrictive material, the band having a first end and a second end defining a gap therebetween, a measuring circuit electrically connected to the first and second ends of the coilless sensor, the measuring circuit being configured to pass a current through the coilless sensor and measure at least one of an inductance, a resistance and an impedance of the coilless sensor in response to the current, and a processor in electrical communication with the measuring circuit, the processor being configured to calculate an amount of stress being applied to the coilless sensor based upon the measured inductance, resistance and impedance.

Abstract: A strain sensor includes a load carrying body configured to strain in response to a load applied along a load path. The sensor further includes a magnetostrictive electrical conductor affixed to the body but out of the load path. Application of the load causes the body to strain, which in turn results in a proportional stress being imparted to the magnetostrictive conductor, altering its magnetic permeability. A circuit is electrically connected to the conductor to detect such changes in permeability, which are indicative of the applied load.

Abstract: This invention relates to a load sensor comprising a member composed of electrically conductive magnetostrictive material. The member is a uniform and continuous distribution of wire or strip material abutting itself between opposite ends. The magnetostrictive material is annealed and abutting portions of the member are spaced apart from one another using insulation incorporating microspheres. Terminals at different portions of the member allow the member to be electrically connected in a circuit for measuring an impedance of the member. Stress applied along an axis of the member causes a change in the member's permeability that is measurable as a change in impedance of the sensor. The configuration of the sensor can be described as coil shaped or accordion shaped. The wire or strip material comprising the sensor comprise a variety of shapes. Insulation comprises a high strength adhesive filled with high strength ceramic microspheres.

Abstract: The present invention is directed to a position sensor, comprising a printed circuit board; a pair of stationary planar air-core coils formed in a trapezoidal or rectangular shape and side-by-side one another on the printed circuit board, coil windings being relatively uniformly distributed over a predetermined area of the printed circuit board; and a moving target formed by a sheet of copper on the printed circuit board.

Abstract: A system for measuring stress including a coilless sensor including at least one band of electrically conductive and magnetostrictive material, the band having a first end and a second end defining a gap therebetween, a measuring circuit electrically connected to the first and second ends of the coilless sensor, the measuring circuit being configured to pass a current through the coilless sensor and measure at least one of an inductance, a resistance and an impedance of the coilless sensor in response to the current, and a processor in electrical communication with the measuring circuit, the processor being configured to calculate an amount of stress being applied to the coilless sensor based upon the measured inductance, resistance and impedance.

Abstract: The present invention is directed to a strain sensor comprising a monolithic magnetostrictive material core wherein the permeability of the material depends on stress, the core having an aperture therein and a coil wound about the core and through the aperture. The core and the coil being configured such that when the coil is connected in circuit, it establishes a loop of magnetic flux that circulates through the core and about the coil whereby impedance of the core is measured. Impedance being a general term including inductance, resistance and a combination of the two. Various configurations for the core are disclosed and integrated housing is also taught. The present sensor can be used to sense force, pressure, torque, acceleration and combinations thereof. The present device can be utilized to sense pressure of diesel fuel in diesel engines, oil pressure, hydraulic pressure, and earth moving and construction vehicles, etc.

Abstract: An apparatus (10) is set forth for measuring a return signal of a magnetostrictive sensor (20) that detects a force, torque, or pressure. The return signal includes noise, a DC resistance (44), an AC resistance and an inductance and the inductance is shifted ninety degrees from the AC resistance. The apparatus (10) includes a sensor filter (22) to remove the noise from the return signal. A sensor filter (22) shifts the return signal and more specifically, the inductance by an additional angle and the sum of the additional angle and the ninety degrees phase shift is defined as the final detection angle. To detect the inductance at the final detection angle, a wave filter (16) and a reference filter (28) shifts a reference signal by the final detection angle to trigger a first demodulator (26) to detect the inductance at the final detection angle. The inductance detected by the first demodulator (26) varies due to temperature.

Abstract: A non-contact position sensor comprises a first reactive element for accepting radio frequency (RF) energy from an oscillator and radiating said RF energy to generate an excitation flux. A second reactive element intercepts the excitation flux and an RF voltage is induced therein. An RF voltage detector, operatively coupled to the second reactive element, detects the RF voltage induced in the second reactive element to generate an output voltage. A third reactive element is capable of intercepting the excitation flux to generate a back electromagnetic force (EMF) in the second reactive element such that, upon the third reactive element being displaced relative to at least one of the first and second reactive elements, the RF voltage detector generates a position-dependent output signal indicative of the displacement of the third reactive element.

Abstract: A sensor assembly for measuring force along an axis (F) comprises an inductance coil extending around the axis (F) for establishing a loop of magnetic flux looping axially through the coil and extending around the axis (F) to define a donut shaped ring of magnetic flux surrounding the axis (F). A core of magnetostrictive material provides a primary path for the magnetic flux in a first portion of the loop of magnetic flux and a magnetic carrier provides a return path for magnetic flux in a second portion of the loop of magnetic flux as the magnetic flux circles the coil through the core and the carrier. A first interface extends radially between the core and the carrier whereby the core and the carrier are urged together at the interface in response to a force applied parallel to the axis (F). Various embodiments or combinations of the core and carrier are illustrated in FIGS. 3–7.

Abstract: A process for forming magnetic target tracks for position and speed sensors. The tracks are formed from a paste comprising a magnetic powder material and a hardenable carrier. The tracks can be formed within trenches in a substrate or on the substrate surface.

Abstract: A sensor apparatus and method that can measure either a linear position or an angular position of a device. A linear array of galvanomagnetic sensing elements is fixedly mountable adjacent the device. A target is connectable to the device such that the target moves adjacent a surface of the linear array in response to movement of the device and is shaped so that a magnetic flux density curve resulting from excitation of the sensing elements includes a peak and/or a valley. A first circuit excites each of the sensing elements, and a second circuit measures a magnetic flux density value at each of the sensing elements. A maximum and/or a minimum of the flux density curve indicates the position of the device.

Abstract: A strain sensor includes a load carrying body configured to strain in response to a load applied along a load path. The sensor further includes a magnetostrictive electrical conductor affixed to the body but out of the load path. Application of the load causes the body to strain, which in turn results in a proportional stress being imparted to the magnetostrictive conductor, altering its magnetic permeability. A circuit is coupled to the conductor to detect such changes in permeability, which are indicative of the applied load.