Abstract: The present invention includes a self-sounding theft prevention tag that issues one of two different sounds, that is, a first alarm or a second alarm in the event of theft, so that an abnormal state where a theft has occurred is detected with sound in a remote location without being interrupted by electromagnetic noise.

Abstract: The present invention includes a self-sounding theft prevention tag that issues one of two different sounds, that is, a first alarm or a second alarm in the event of theft, so that an abnormal state where a theft has occurred is detected with sound in a remote location without being interrupted by electromagnetic noise.

Abstract: Method for producing a magnetostrictive torque sensor shaft and a torque sensor shaft made according to the method. Knurl grooves are formed on the surface of shaft base material in oblique relation to the axis thereof, which are then subjected to heat treatment. Subsequently, material having less crystallomagnetic anisotropy and a large magnetostriction constant is deposited by plating, thermal spraying or otherwise at least on the surface of the knurl grooves included in the outer periphery of the shaft base material thereby to form a magnetostrictive layer. Preferably, the magnetostrictive layer is comprised of an FeNi alloy plated layer whose Fe component content is more than 0% but less than 25%. Thus, a sensor shaft is obtained which can be suitably used in constructing a magnetostrictive torque sensor having high performance characteristics.

Abstract: The invention relates to a method of producing magnetostriction type torque sensor shafts adapted to detect a change in permeability when a torque is applied. A plurality of shot peening operations are applied to the surface of a torque sensor shaft in such a manner that the diameter of shot particles to be used is decreased each time. This arrangement ensures that the region in which the residual stress is at a maximum and approximately constant lies over a wide range as seen in the direction of the depth from the outermost surface of the shaft and extends from a deep area to an area close to the surface of the shaft. As a result, the hysteresis and nonlinearity of the shaft are improved and it becomes possible to use a wide range of excitation frequencies.

Abstract: A torque sensor shaft for a non-contacting torque sensor including magnetically anisotropic portions formed on the surface of the shaft. Absolute value of angle of inclination of the anisotropic directions of the magnetically anisotropic portions is set lower than 40 degree so as to permit reduction of stress components in the anisotropic directions from their level in the case where the absolute value of the angle is 45 degree. By such angle setting it is possible to prevent possible decrease in sensor sensitivity and, in addition, to obtain good improvement in the point of magnetic saturation due to torque applied, thereby to obtain an improved dynamic range.

Abstract: A device for measuring torque in a shaft without contacting the latter. A torque transmitting shaft is formed with at least one detecting magnetically anisotropic region inclined to form an angle with respect to the axis of rotation of this shaft. A detecting coil is disposed on the periphery of the detecting magnetically anisotropic region. When the detecting voltage for the detecting coil changes owing to temperature changes and time-dependent changes, the changes in the detection sensitivity and in the zero point take place, leading to errors during torque measurement. Correct measured values can be obtained by having a device for correcting such changes in sensitivity and zero point.

Abstract: A device for measuring torque in a shaft without contacting the latter. A torque transmitting shaft is formed with at least one detecting magnetically anisotropic region inclined to form an angle with respect to the axis of rotation of this shaft. A detecting coil is disposed on the periphery of the detecting magnetically anisotropic region. When the detecting voltage for the detecting coil changes owing to temperature changes and time-dependent changes, the changes in the detection sensitivity and in the zero point take place, leading to errors during torque measurement. Correct measured values can be obtained by having a device for correcting such changes in sensitivity and zero point.

Abstract: A device for measuring torque in a shaft without contacting the latter. A torque transmitting shaft is formed with at least one detecting magnetically anisotropic region inclined to form an angle with respect to the axis of rotation of this shaft. A detecting coil is disposed on the periphery of the detecting magnetically anisotropic region. When the detecting voltage for the detecting coil changes owing to temperature changes and time-dependent changes, the changes in the detection sensitivity and in the zero point take place, leading to errors during torque measurement. Correct measured values can be obtained by having a device for correcting such changes in sensitivity and zero point.

Abstract: A magneto-strictive torque sensor for electrically contactlessly detecting a torque applied to a rotary shaft on the basis of a resulting change in the magnetic permeability of the surface of the shaft. Fine dents and retainer areas for retaining residual compressive stress due to the fine dents are formed on the surface of the rotary shaft. According to this arrangement, the process of magnetization resulting from the application of an exciting magnetic field and of the torque to the rotary shaft involves less magnetization due to magnetic domain wall displacement and consists principally of reversible magnetic rotation, with the result of reduced hysteresis in the magnetization process. The reduced hysteresis causes less hysteresis involved in torque detection and higher detection sensitivity, thus resulting in high accuracy of torque detection.

Abstract: A device for measuring torque in a shaft without contacting the latter. A torque transmitting shaft is formed with at least one detecting magnetically anisotropic region inclined to form an angle with respect to the axis of rotation of this shaft. A detecting coil is disposed on the periphery of the detecting magnetically anisotropic region. When the detecting voltage for the detecting coil changes owing to temperature changes and time-dependent changes, the changes in the detection sensitivity and in the zero point take place, leading to errors during torque measurement. Correct measured values can be obtained by having a device for correcting such changes in sensitivity and zero point.