Drive axle control system
First Claim
1. A speed control system for a tandem drive axle having a front axle coupled to a rear axle comprising:
- a plurality of wheel speed sensors for measuring wheel speeds at each driven wheel and generating wheel speed signals;
an electronic controller for comparing said wheel speed signals to each other to determine differences in tire rolling radii and generating a first tire signal if said differences are within a predetermined range; and
a tire pressure adjustment mechanism controlled by said electronic controller and operably connected to each tire mounted to the wheels to adjust tire pressure such that each tire rolling radius is maintained within a predetermined percentage range with respect to all of the tires.
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Accused Products
Abstract
Tandem drive axles include a pair of drive axles interconnected by a thru-shaft. An inter-axle differential allows speed differentiation between the pair of axles. Differences in tire rolling radii and variations in axle load distribution between the pair of drive axles are examples of why axle differentiation is needed. By measuring and monitoring wheel speed and/or tire pressure, tire rolling radii differences can be determined and appropriate adjustments can be made to tire pressures to provide a common tire rolling radii range for all tires. In addition to tire pressure adjustment, by adjusting other axle parameters that affect axle performance, such as suspension height and weight distribution, the need for axle differentiation is eliminated.
28 Citations
17 Claims
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1. A speed control system for a tandem drive axle having a front axle coupled to a rear axle comprising:
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a plurality of wheel speed sensors for measuring wheel speeds at each driven wheel and generating wheel speed signals;
an electronic controller for comparing said wheel speed signals to each other to determine differences in tire rolling radii and generating a first tire signal if said differences are within a predetermined range; and
a tire pressure adjustment mechanism controlled by said electronic controller and operably connected to each tire mounted to the wheels to adjust tire pressure such that each tire rolling radius is maintained within a predetermined percentage range with respect to all of the tires. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A control system for a heavy duty vehicle comprising:
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an engine coupled to a driveshaft for providing driving torque;
a tandem axle having a front drive axle coupled to a rear drive axle with a thru-shaft, said front drive axle including a first center differential coupled to said driveshaft to provide the driving torque to a first pair of driving wheels supporting a first plurality of tires and said rear drive axle including a second center differential coupled to said first center differential with said thru-shaft to provide the driving torque to a second pair of driving wheels supporting a second plurality of tires;
a plurality of wheel speed sensors for measuring wheel speed at each of said driving wheels and generating wheel speed signals;
an electronic controller for determining a tire rolling radius for each of said tires based on said wheel speed signals; and
a tire pressure adjustment mechanism controlled by said electronic controller to selectively adjust tire pressure to achieve a desired common tire rolling radius range. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification