A torque measurement device includes a case that does not rotate even during use; a rotating shaft rotatably supported to the case and having a magnetostrictive effect part whose magnetic permeability changes according to a transmitted torque; and a magnetostrictive sensor having a detection part arranged closely adjacent to the magnetostrictive effect part so that a voltage changes according to change of the magnetic permeability of the magnetostrictive effect part, and being supported to the case; and the torque measurement device has a rotation-preventing construction configured to prevent the magnetostrictive sensor from rotating with respect to the case.

A torque sensor for use in an electric power assisted steering system comprises a first shaft, a second shaft, and a torsion bar, a hollow sleeve that is secured to the first shaft and extends along the torsion bar to at least partially axially overlap the second shaft, angular deflection indicating means that produce a signal that is dependent on the angular deflection of the first shaft relative to the second shaft as a torque is applied across the torque sensor that causes the torsion bar to twist, at least one drive dog fixed to the sleeve and at least one corresponding drive dog fixed to the second shaft, in normal operation the two dogs being offset so that they permit a defined range of angular deflection of the torsion bar but will engage each other to provide a path for torque to be transferred from the first shaft to the second shaft in the event of a failure of the torsion bar, and a connecting element which has a first part that is secured within a bore in one of the second shaft and the sleeve, the connecting element having a second part that extends into a feature of the other of the second shaft and the sleeve, at zero torque across the torque sensor the connecting element being spaced circumferentially from the feature by an angular distance greater than the spacing between the drive dogs and spaced from the feature in a direction along the axis of the shafts that is less than the overlap of the drive dogs in that direction to prevent the shafts moving apart in the event of failure of the torsion bar by an amount that would otherwise prevent the drive dogs engaging.

A torque sensor includes a disk comprising a magnetostrictive, magnetically biased, or magnetizable material, and a magnetic field sensor assembly. A torque acting about an axis of rotation of the disk can be applied to the disk and the magnetostrictive material is configured to generate a magnetic field outside the disk that changes dependent on the effective torque. The magnetic field sensor assembly is configured to output a signal based on the magnetic field generated by the magnetostrictive material, and the torque sensor is configured to determine a value of the acting torque based on the signal that is output.

A method for measuring stress applied to a magnetoelastic body, simultaneously detecting a potential external magnetic field affecting a magnetoelastic sensor and allocating a non-stress related influence affected by the field on the body, including applying at least two opposite magnetic zones on the body, providing at least one sensor including at least one first (1) and second (2) channel having at least two axially aligned coils each, arranged adjacent to the magnetized zone of the body, both channels having different sensitivity relative to the field, setting-up channel 1 as a common mode rejection channel and channel 2 as a common mode acceptance channel, reading the magnetized zones when stress is applied to the body, measuring the stress by channel 1 leading to an opposite sensitive direction, and detecting the impact of the field to the magnetized zones by channel 2 leading to an identical sensitive direction.

A drive bearing includes an element rotatably mounted and which comprises magnetized magnetostrictive material. A torque can be applied to the element and the magnetostrictive magnetized material is formed to generate at a first position outside the element a magnetic field as a function of the torque applied. A measuring circuit comprises a first magnetic field sensor for detecting a total magnetic field at the first position, the total magnetic field comprising the magnetic field generated by the magnetostrictive magnetized material and an external magnetic field. The first magnetic field sensor outputs a first signal as a function of the total magnetic field detected. A second magnetic field sensor detects the external magnetic field at a second position and outputs a second signal as a function of the external magnetic field detected. The measuring circuit determines a value of the torque applied using the first and the second signals.

A torque measurement device includes a case that does not rotate even during use; a rotating shaft rotatably supported to the case and having a magnetostrictive effect part whose magnetic permeability changes according to a transmitted torque; and a magnetostrictive sensor having a detection part arranged closely adjacent to the magnetostrictive effect part so that a voltage changes according to change of the magnetic permeability of the magnetostrictive effect part, and being supported to the case; and the torque measurement device has a rotation-preventing construction configured to prevent the magnetostrictive sensor from rotating with respect to the case.

A torque load member has a detected surface which is configured to face a magnetostrictive torque sensor. The detected surface is a shot peened surface whose magnetic anisotropy directed in a specific direction has been reduced by performing shot peening thereto at an arc height value of 0.31 mmA or more.

A sensor for at least detecting steering torque of a steel steering column includes a magnetic field generating element which is configured to generate a magnetic field. The magnetic field penetrates the steering column so as to magnetize a steel material thereof. The sensor also includes a magnetic field detection element which is configured to detect a magnetic field change caused by a magnetoelastic effect of the magnetized steel material of the steering column when the steering column is subjected to torque stress. An output signal of the magnetic field detection element characterizes steering torque. The sensor also includes a base plate bearing the magnetic field generating element and the magnetic field detection element. The base plate is spaced from and separate from the steel steering column. The magnetic field generating element and the magnetic field detection element are directly mounted on the base plate.

A control assembly for controlling a speed or torque of operation of an electric device includes a control assembly housing, a magnetic sensor, a magnetic element; and an actuator. The actuator moves relative to the control assembly and, responsive to that movement, the magnetic sensor and magnetic element are moved relative to each other between a first position and a second position so that the magnetic sensor senses a first magnetic field reading when in the first position and senses a second magnetic field reading when in the second position. A control module is operably connected to the magnetic sensor and configured for controlling the electric device, and a magnetic shielding element is positioned within the control assembly housing to alleviate a magnetic signal source external to the control assembly from interfering with the sensing by the magnetic sensor.

To improve the output signal quality of a load measurement by means of active magnetization, the invention provides a load measurement method for measuring a mechanical load on a test object (14), comprising: a) generating and applying a magnetic field to the test object (14); b) detecting a magnetic field changed by the test object (14) as a result of a mechanical load on the test object (14) by means of a first magnetic field detection device (20) to generate a first measurement signal (U1, UAB), c) detecting a magnetic field changed by the test object (14) as a result of a mechanical load on the test object (14) by means of a second magnetic field detection device (22) to generate a second measurement signal (U1, UAB), d) computationally determining a third measurement signal (UBT) from the first measurement signal (U1, UAB) and the second measurement signal (U2, UAT), and preferably comprising the steps of e) forming a difference from one (U2, UAT) of the first and the second measurement signals and the computationally determined third measurement signal (UBT) to produce an output signal, f) determining the mechanical load applied to the test object (14) based on the output signal. The invention also provides a corresponding load measurement device for carrying out the load measurement method.