Sensing device for detecting the rotational speed of a rotating element mounted on a non-rotating element by means of a bearing

A device for sensing the rotational speed of a rotating element mounted on a non-rotating element by means of a roller bearing, said device comprising:

• coding means integral with the rotating element, said coding means having a multipolar ring which has a plurality of magnetic segments with regularly and alternately arranged magnetic poles for producing an alternating magnetic field during rotation;
• sensor means made integral with the non-rotating element, and
• magnetic flux concentrating means of annular shape arranged in the immediate vicinity of the multipolar ring and cooperating with the sensor means in order to concentrate and channel magnetic flux emitted by the multipolar ring, the flux concentrating means including a first end shield and a second end shield, said first end shield including a radial part with a circular edge provided on its circumference with a sealing lip for providing a seal between the rotating and non-rotating elements, said second end shield having radial teeth which are spaced regularly along a circular path,
• said multipolar ring being axially magnetized and arranged in an axial space which lies between the radial part of the fist end shield and the radial teeth of the second end shield, said radial teeth simultaneously being axially aligned with magnetic poles of the same polarity of the multipolar ring.