Patent ID: 7928611
Filing Date: 2011-04-19
Classification: G01D,H02K

Abstract:
1. An electric motor, comprising: a first motor part; a second motor part, with the first motor part moveable in relation to the second motor part in a movement direction, the second motor part having pole teeth in the absence of magnets and separated from one another along the movement direction; and a measurement system determining a position or movement of the first motor part and including a plurality of magnetic field sensor devices which are attached to the first motor part and separated from one another along the movement direction, with neighboring magnetic field sensor devices being spaced apart by a distance which is different than a distance between neighboring pole teeth, wherein each of the magnetic field sensor devices has at least one magnet whose magnetic field is passed through one of the pole teeth for detection by means of a sensor of the magnetic field sensor devices, and wherein each of the magnetic field sensor devices includes a U-shaped yoke section having a free end face, with the sensor arranged in or on the yoke section, and with two magnets which are directed or directable in opposite directions, being arranged at the free end of the yoke section to produce magnetic fluxes, which are directed in opposite directions and detectable by the sensor in the yoke section as a function of the position of the magnets with respect to one of the pole teeth of the first motor part.