Magnetic encoder and wheel support bearing assembly using the same

Abstract

A magnetic encoder which can be assembled having a thin-walled structure while securing an excellent detection sensitivity and which can provide an excellent moldability by suitably selecting materials. The magnetic encoder includes a multi-pole magnet having a plurality of opposite magnetic poles alternating in a direction circumferentially thereof, and a core metal for supporting the multi-pole magnet. The multi-pole magnet contains a powdery magnetic material mixed in an amount within the range of 20 to 90 vol. % relative to the total volume of the multi-pole magnet. The multi-pole magnet may be a sintered magnet.

1 . A wheel support bearing assembly provided with a magnetic encoder, the encoder comprising:
 a multi-pole magnet in the form of a plastics magnet having a plurality of opposite magnetic poles alternating in a direction circumferentially thereof; and   a core metal to support the multi-pole magnet,   wherein the multi-pole magnet is of a disc-shaped configuration and of a kind prepared by mixing a plastomer with a powdery magnetic material, said powdery magnetic material being mixed in an amount within the range of 30 to 80 vol. % relative to the total volume of the multi-pole magnet,   wherein the wheel support bearing assembly supports a wheel for rotation relative to a vehicle body and comprises
 an outer member having an inner peripheral surface formed with a plurality of first raceways; 
 an inner member having a corresponding number of second raceways defined therein in alignment with the first raceways in the outer member; 
 rows of rolling elements rollingly received in part with the first raceways and in part with the second raceways; 
 a sealing unit to seal an annular bearing space delimited between the outer member and the inner member, and including a first sealing plate of generally L-sectioned configuration mounted on one of the outer and inner members which serves as a rotatable member, and a second sealing plate of a generally L-sectioned configuration mounted on the other of the outer and inner members which serves as a stationary member, and positioned in face-to-face relation with the first sealing plate, the first sealing plate defining the core metal of the magnetic encoder and having a cylindrical axial wall and a radial upright wall; and 
 an elastic sealing member including a side sealing lip and at least one radial sealing lip, the elastic sealing member being secured to the second sealing plate with the side sealing lip slidingly engaging the radial upright wall of the first sealing plate and with the least one radial sealing lip slidingly engaging the cylindrical axial wall, and 
   wherein the multi-pole magnet is mounted on the radial upright wall of the first sealing plate.