Patent ID: 6522133
Filing Date: 2003-02-18
Classification: F16H,G01P

Abstract:
A rotation detector for use in a transmission for determining the rotation of a cylinder enclosed and rotating within an outer concentric part of the transmission, the outer concentric part consisting of a non-magnetizable material and having a generally solid wall in the region of the rotation detector, comprising:a Hall-effect magnetic field sensor stationarily situated in a recess in a wall of a housing concentrically spaced apart from an outer periphery of the outer concentric part and in the region of the field sensor, and a magnetic field generator including a magnet ring located concentrically with an outer periphery of the cylinder and having a shape of a field spider, the magnet ring having a substantially T-shaped cross-section having a longitudinal bar and a transverse bar having a first arm and a second arm, the first arm and the second arm extending outward at generally right angles from a first side and a second side of the longitudinal bar, a first arm of the magnet ring extending into a corresponding circumferential recess in the cylinder, the recess being spaced inwards from the outer periphery of the cylinder and extending axially to the cylinder so that the magnet ring is connected to the cylinder to resist centrifugal forces resulting from rotation of the cylinder, and the longitudinal bar of the spider extending from the recess and towards the outer periphery of the cylinder to locate the magnetic field towards the periphery of the cylinder and the field sensor.