A sensor unit for a rotational angle measurement system for detecting a rotational movement of a drive shaft includes a housing arrangement with a pot-shaped housing part, a carrier member, a sensor printed circuit board arranged on the carrier member, and a bearing which, in an operating state, mounts the sensor printed circuit board in a stationary manner in the housing arrangement with respect to the drive shaft. The bearing is a form fit/force fit arrangement so that the carrier member is movably mounted in the housing arrangement in a pre-assembled state.

An encoder applied to a rotatable device including a code disc set, at least one bearing, a bearing housing, a main housing, a sensor and an elastic assembly. The code disc set is disposed on a rotation end of the rotatable device. The bearing is disposed around the rotation end, and the bearing housing is disposed around the bearing. The main housing is connected with a first end of the bearing housing. The sensor is disposed on the main housing and corresponds to the disc wheel set, and there is an interval between the sensor and the code disc set. The elastic assembly is connected with a second end of the bearing housing and a fixing end of the rotatable device. Therefore, the interval between the sensor and the code disc set is maintained to be fixed, and the good position detection performance and stable signals are obtained.

There is provided a machine tool for suppressing the adverse effect of run-out of the rear end of a spindle on the rotation detection accuracy when processing a workpiece within a processing area. The machine tool includes a rotation driver, the spindle that is rotated by the rotation driver, a rotational angle detector that is provided to face a part forming the spindle in order to detect a rotational angle of the spindle, and at least two bearings that support the spindle and are arranged on a side of the processing area with respect to the rotation driver. The rotational angle detector is arranged at a position on the side of the processing area with respect to the rotation driver, the position being on the side of the processing area with respect to the bearings, on a side of the rotation driver with respect to the bearings, or between the bearings.

An apparatus is provided for detecting an external magnetic field and/or a product-related magnetic field on a ferromagnetic component, which has a magnetization in the form of magnetic tracks. The apparatus comprises at least two magnetic field sensors which can detect an external magnetic field acting on the ferromagnetic component. Each magnetic field sensor comprises two coils, wherein each coil is assigned at least one magnetic track. Each two coils are configured so that they have a different sensitivity to one another, wherein one coil which has a higher sensitivity with respect to the other coil. The coil having the higher sensitivity ensures that the effect of an external magnetic field is amplified.

An electric motor includes a cylindrical holder mounted to an end of a rotation shaft, a sensor magnet mounted to the holder, and a rotation sensor mounted at a position at which the rotation sensor opposes the sensor magnet in a direction of an axis of rotation and detecting a rotating field of the sensor magnet. The end of the rotation shaft has a cylindrical shape with a non-circular cross section formed of at least one plane and a curved surface in an outer peripheral portion. At least one of an inner peripheral portion and an outer peripheral portion of the holder forms a non-circular cross section formed of a plane parallel to the axis of rotation and a curved surface connected to the plane. The plane of the rotation shaft and the plane of the holder are parallel to each other and the curved surface of the rotation shaft and the curved surface of the holder are in contact with each other.

There is provided a mounting tool, for a linear displacement measuring apparatus, which is capable of reducing thermal stress of a scale housing case and is detachable while having a simple structure.

The mounting tool includes a cylindrical bush inserted into a through hole drilled in the scale housing case, an O-ring interposed between an inside wall of the through hole and the bush, a mounting screw inserted into a cylindrical hole of the bush and screwed into a mounting face, and a plate spring arranged between a head part of the mounting screw and an outside face of the scale housing case, and biasing the scale housing case toward the mounting face.

An apparatus is provided for detecting an external magnetic field and/or a product-related magnetic field on a ferromagnetic component, which has a magnetization in the form of magnetic tracks. The apparatus comprises at least two magnetic field sensors which can detect an external magnetic field acting on the ferromagnetic component. Each magnetic field sensor comprises two coils, wherein each coil is assigned at least one magnetic track. Each two coils are configured so that they have a different sensitivity to one another, wherein one coil which has a higher sensitivity with respect to the other coil. The coil having the higher sensitivity ensures that the effect of an external magnetic field is amplified.