Bearing assembly for an electric motor, and electric motor
AssigneeAktiebolaget Skf
InventorsAzeez Abdul, Hendrik Anne Mol, Frank Fiddelaers
Life of this patent
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Abstract
At least one main bearing is configured to support a rotational element of the electric motor, and a sacrificial bearing. The main bearing includes at least one inner ring, at least one outer ring and at least one plurality of rolling elements. The sacrificial bearing provides an outer ring, an inner ring, and a plurality of rolling elements disposed between the outer ring and the inner ring. A value of a breakdown voltage for the sacrificial bearing is less than a value of the breakdown voltage for the at least one main bearing.
Claims10
A bearing assembly for an electric motor for a vehicle, the electric motor having a rotor shaft, the rotor shaft having a radially innermost surface, the bearing assembly comprising:
- at least one main bearing configured to support the rotor shaft of the electric motor, the main bearing comprising at least one inner ring providing at least one inner raceway, at least one outer ring providing at least one outer raceway, the inner and outer rings being in relative rotation, and at least one plurality of rolling elements disposed between the inner and outer rings, one of the bearing rings being coupled in rotation with the rotor shaft of the electric motor,
- a sacrificial bearing comprising an inner ring with an inner raceway, an outer ring with an outer raceway and a radially outermost surface, the inner and outer rings being in relative rotation, and a plurality of rolling elements disposed between the inner and outer rings, one of the sacrificial bearing rings being coupled in rotation with the rotor shaft of the electric motor, the other ring being grounded, and configured so that (i) the conductivity of the sacrificial bearing is higher than 20 μS, and (ii) a value of a breakdown voltage for the sacrificial bearing is less than a value of the breakdown voltage for the at least one main bearing, the radially outermost surface of the outer ring is configured to be positioned radially within the radially innermost surface of the rotor shaft.
An electric motor comprising:
- a case,
- a stator having stator windings,
- a rotor having a rotor shaft and rotor windings,, the rotor shaft having a radially innermost surface defining a hollow therein, and
- at least one bearing assembly having for an electric motor for a vehicle, comprising:
- at least one main bearing configured to support a rotational element of the electric motor, the main bearing comprising at least one inner ring providing at least one inner raceway, at least one outer ring providing at least one outer raceway and a radially outermost surface, the inner and outer rings being in relative rotation, and at least one plurality of rolling elements disposed between the inner and outer rings, one of the bearing rings being coupled in rotation with the rotational element of the electric motor, a sacrificial bearing comprising an inner ring with an inner raceway, an outer ring with an outer raceway, the inner and outer rings being in relative rotation, and a plurality of rolling elements disposed between the inner and outer rings, one of the sacrificial bearing rings being coupled in rotation with the rotational element of the electric motor, the other ring being grounded, and configured so that (i) the conductivity of the sacrificial bearing is higher than 20 μS, and (ii) a value of a breakdown voltage for the sacrificial bearing is less than a value of the breakdown voltage for the at least one main bearing, the radially outermost surface of the outer ring is positioned within the hollow and is positioned radially within the radially innermost surface of the rotor shaft, wherein
- at least one main bearing of the bearing assembly is configured to support the rotor shaft of the electric motor, and it further comprises a sacrificial bearing.
Dependencies are inferred from the claim text.