Live spindle design for heavy duty steer axle
A heavy duty steer axle assembly with a live spindle is provided. The assembly includes an axle beam extending transversely across the vehicle, a kingpin disposed within a kingpin bore in the axle beam, a knuckle mounted on the kingpin and rotatable relative to the axle beam, and a spindle hub configured to mount a wheel of the vehicle. A bearing assembly is disposed between the knuckle and spindle hub to allow rotation of the spindle hub. The assembly enables use of a cast, rather than forged, knuckle, allows for removal and service of the vehicle's brake rotor without removal or readjustment of the vehicle's wheel bearings, and allows for an external wheel flange that can be easily replaced with flanges of varying offset, without requiring a new wheel hub assembly.
1 . A steer axle assembly for a vehicle, comprising:
an axle beam extending transversely across said vehicle, said axle beam having a kingpin bore at a first end;
a kingpin disposed in said kingpin bore;
a knuckle mounted on said kingpin and rotatable relative to said axle beam;
a spindle hub configured to mount a wheel of said vehicle; and,
a bearing assembly disposed between said knuckle and said spindle hub.
2 . The steer axle assembly of claim 1 wherein said knuckle comprises a flange defining a recess in which said bearing assembly and said spindle hub are received.
3 . The steer axle assembly of claim 2 wherein said recess opens in an outboard direction.
4 . The steer axle assembly of claim 1 wherein said bearing assembly is pressed onto said spindle hub.
5 . The steer axle assembly of claim 1 wherein said spindle hub defines a pair of opposed shoulders between which said bearing assembly is retained.
6 . The steer axle assembly of claim 1 wherein bearing assembly is retained between a shoulder defined in said spindle hub and a nut disposed about a threaded portion of said spindle hub.
7 . The steer axle assembly of claim 1 wherein said bearing assembly includes a bearing cup forming a plurality of outer races.
8 . The steer axle assembly of claim 1 wherein said bearing assembly includes a bearing cup defining a radially extending flange, said flange defining a bore configured to align with a corresponding bore in said knuckle, said bearing cup flange bore and said knuckle bore configured to receive a fastener.
9 . The steer axle assembly of claim 1 , further comprising a brake rotor, said brake rotor supported on said spindle hub.
10 . The steer axle assembly of claim 9 wherein said spindle hub defines a radially extending flange, said brake rotor coupled to said flange by a plurality of fasteners.
11 . The steer axle assembly of claim 1 wherein said knuckle is cast.
12 . The steer axle assembly of claim 1 further comprising a unitary steering member coupled to said knuckle, said steering member defining a steer arm and a tie rod arm.
13 . The steer axle assembly of claim 1 wherein said spindle hub defines a radially extending flange proximate an outboard end, an outer diameter of said flange varying to define a plurality of peaks and a plurality of valleys, at least some of said valleys aligned with, and thereby permitting access to, fasteners coupling said bearing assembly to said knuckle.