Kubota Corporation

Shigeo Yoshimura

Renshiro Ishino

Hitoshi Kimura

Shiro Takada

Taro Saito

Mutsumi Sunahata

Yoshio Shibata

Yoshiaki Shimada

Yasuo Tanizaki

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.

Torque sensor shaft

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.

Torque measure device

Torque measuring device

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. Further, by working the surface of the rotary shaft for the purpose of forming the fine dents thereon, microdefects present on the surface layer of the rotary shaft are reduced or eliminated and thus reduced hysteresis and improved sensitivity can be attained in the process of torque detection.

Magneto-strictive torque sensor

Magnetically anisotropic torque measuring device with error correction

A load cell (24, 31, 40, 51, 58, 62, 64, 68, 92, 96, 97) having flame proof function has a load cell body (2) and a flame proof enclosure (25, 33, 36, 41, 69, 78) for covering at least a strain gage carrying portion (5) of the load cell body (2). A load receiving portion (4) connected with the strain gage carrying portion (5) for transmitting a load to the strain gage carrying portion, projects outwardly from the flame proof enclosure. A gap (30) is defined between a first surface of the load cell body and a second surface of the enclosure, so that the load receiving portion (4) and the strain gage carrying portion (5) are freely movable relative to the enclosure. The size of the gap width W.sub.1 and of the gap length L.sub.1 are selected for realizing the flame proof function.

Load cell having flameproof function

Growing community of inventors

Hirakata, Japan

Shigeo Yoshimura