Patent ID: 7530415
Filing Date: 2009-05-12
Classification: B60K,B60L,B62D,H02K,Y02T

Abstract:
1. A traction assembly comprising: a wheel having a rotational axis, and a first radius extending from the rotational axis to an exterior surface of the wheel, wherein the exterior surface of the wheel engages a static, non-rotating surface while the traction assembly is in operation; an electric motor that directly drives the wheel, wherein the electric motor includes a rotor situated around the rotational axis at a second radius from the rotational axis, and a stator situated around the rotational axis at a third radius from the rotational axis, wherein the second radius is different from the third radius; a gap situated around the rotational axis between the rotor and the stator; wherein the electric motor, while in operation, exerts torque that fully and automatically drives the wheel, the torque having an arm extending from the rotational axis to a surface of the gap; and wherein the traction assembly has a traction ratio, defined as the arm of the torque divided by the first radius, which is larger than 0.57.