Patent ID: 7455459

Claim:
An oil lubricated rotating hub and stationary spindle assembly, said assembly comprising: a spindle defining a rotary axis; a hub supported on said spindle for rotation about said axis; an oil bath seal for establishing a dynamic sealing interface between said hub and said spindle, said oil bath seal including a metallic carrier fixed relative to said hub and a flexible sealing element extending from said carrier for establishing a fluid impervious seal during relative rotation between said hub and said spindle; an annular encoder ring disposed on said carrier and positioned concentrically about said axis, said encoder ring having an exposed face comprising a plurality of magnetically polarized sectors alternating between North and South polarity; and a variable reluctance sensor disposed adjacent said encoder ring for projecting a magnetic field toward said polarized sectors and producing a sinusoidal wave current in response to the movement of said polarized sectors therethrough, said sinusoidal wave current having a frequency proportional to the rotational velocity of said hub.