Wheel bearing apparatus incorporated with an in-wheel motor

A wheel bearing apparatus incorporating an in-wheel motor comprising:

• a wheel bearing;
• a planetary reduction gear mounted on the wheel bearing;
• an electric motor (M) for driving the planetary reduction gear;
• and
• a driving portion having a rotation member;
• the wheel bearing includes an outer member integrally formed on an outer circumference with a body mounting flange and the outer member inner circumference including double row outer raceway surfaces;
• an inner member includes a wheel hub and at least one inner ring;
• the wheel hub is integrally formed, on its one end, with a wheel mounting flange to mount a wheel, the inner member outer circumference includes an axially extending cylindrical portion, and the inner member inner circumference includes a torque transmitting serration, the inner ring is press-fit onto the cylindrical portion of the wheel hub, and the inner member outer circumference includes the inner raceway surfaces arranged opposite to the double row outer raceway surfaces;
• a caulked portion is formed by plastically deforming an end of the cylindrical portion of the wheel hub for axially securing the inner ring;
• double row rolling elements are freely rollably contained between the outer and inner raceway surfaces;
• the planetary reduction gear comprises:
• an input element arranged on the rotation member;
• a stationary element arranged on the inner circumference of the outer member;
• multiple planetary elements arranged between the stationary element and the input element;
• output elements rotationally support the planetary elements relative to a connecting shaft;
• the driving portion comprises:
• a stator housing forming a portion of the electric motor (M) and arranged on the outer member;
• a stator portion built in the stator housing;
• and
• a rotor portion secured on the rotation member and arranged opposite to the stator portion via a predetermined air gap;
• the connecting shaft is detachably connected to the wheel hub, via serrations, to transmit the rotation of the electric motor (M) to the wheel hub via the planetary reduction gear so as to drive the wheel;
• the connecting shaft comprises a disc portion forming the planetary elements, and a shaft portion axially extending from the disc portion via a shoulder portion, the connecting shaft outer circumference includes the serration;
• the connecting shaft is inserted into the wheel hub until the disc portion abuts the inner member such that the disc portion located in the radially inner direction of the outer member is in contact with the caulked portion of the wheel hub;
• and
• a seal ring is interposed adjacent the inner member and the connecting shaft to shield the driving portion from the outside in a liquid-tight manner.