Wheel support bearing assembly with magnetic encoder
To provide a wheel support bearing assembly capable of securing a satisfactory sealability and of accomplishing an assured press-fit of an magnetic encoder, the wheel support bearing assembly for supporting a vehicle wheel rotatably relative to a vehicle body structure includes an outer member 2 , an inner member 1 positioned inside the outer member 2 with an annular bearing space delimited between it and the outer member 2 , and rows of rolling elements 3 rollingly within the annular bearing space. At least one sealing unit 5 is provided for sealing one of opposite open ends of the annular bearing space. This sealing unit 5 is comprised in part of a magnetic encoder 10 including a multi-pole magnet member 14 having a plurality of opposite magnetic poles alternating in a direction circumferentially thereof and a first sealing plate 11 serving as a core metal. The first sealing plate 11 is press-fitted onto the inner member 1 with the amount of interference fit to be within the range of 5 to 230 μm.
1. A wheel support bearing assembly for rotatably supporting a vehicle wheel relative to a vehicle body structure, said wheel support bearing assembly comprising:
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, said inner member being positioned inside the outer member with an annular bearing space delimited between the inner member and the outer member;
rows of rolling elements rollingly received in part within the first raceways and in part within the second raceways;
at least one sealing unit to seal one of opposite open ends of the annular bearing space, said at least one sealing unit including a first sealing plate of a generally L-sectioned configuration, having a first axial cylindrical wall mounted on one of the outer and inner members which serves as a rotatable member and a first radial upright wall extending radially from the first axial cylindrical wall, and also including a second sealing plate of a generally L-sectioned configuration positioned in face-to-face relation with the first sealing plate and mounted on the other of the outer and inner members which serves as a stationary member, said second sealing plate having a second axial cylindrical wall and a second radial upright wall protruding radially from the second axial cylindrical wall;
an elastic sealing member, secured to the second sealing plate, including a side sealing lip slidingly engaging the first radial upright wall of the first sealing plate and at least one radial sealing lip slidingly engaging the first axial cylindrical wall of the first sealing plate; and
a magnetic encoder including a multi-pole magnet member fixedly mounted on the first radial upright wall of the first sealing plate, said first sealing plate cooperating with the multi-pole magnet member to define the magnetic encoder, said first sealing plate being mounted on the rotating member under an interference fit with the amount of interference fit within the range of 5 to 230 μm.
wherein the multi-pole magnet member of the magnetic encoder is a sintered element prepared by sintering a mixture of a powdery magnetic material and a powdery non-magnetic material, the amount of the powdery non-magnetic metallic material being within the range of 1 to 90 vol. % relative to the total volume of the multi-pole magnet member, and
each of the powdery magnetic material and the powdery non-magnetic material has an average particle size within the range of 10 to 230 μm.
2. The wheel support bearing assembly as claimed in claim 1 , wherein the first radial upright wall of the first sealing plate of the magnetic encoder includes an annular inner portion and an annular outer portion continued from and offset axially from the annular inner portion.
3. The wheel support bearing assembly as claimed in claim 1 , wherein at least one of the multi-pole magnet member of the magnetic encoder and one of opposite surfaces of the first sealing plate where the multi-pole magnet member is fixedly mounted is treated for rust-proofing.
4. The wheel support bearing assembly as claimed in claim 3 , wherein the rust-proofing treatment is carried out to form a rust-proofed coating with a highly anti-corrosive clear paint.
5. The wheel support bearing assembly as claimed in claim 1 , wherein the first radial upright wall of the first sealing plate is formed with a second axial cylindrical wall and wherein the multi-pole magnet member is mounted on an outer peripheral surface of the second axial cylindrical wall instead of being mounted on the first radial upright wall.
6. The wheel support bearing assembly as claimed in claim 1 , wherein the amount of the powdery non-magnetic metallic material is within the range of 5 to 85 vol. % relative to the total volume of the multi-pole magnet member.
7. The wheel support bearing assembly as claimed in claim 1 , wherein the amount of the powdery non-magnetic metallic material is within the range of 10 to 80 vol. % relative to the total volume of the multi-pole magnet member.