Abstract: A method and system for detecting wheel slippage uses a turn sensor to detect a vehicle turning radius in order to predict the difference in wheel speed between wheels on the outside of the turning radius and wheels on the inside of the turning radius. The turn sensor detects the turning radius of the vehicle and signals a controller. The controller utilizes the signal from the turn sensor to predict a difference in wheel speeds between the wheel to the inside of the turn and the wheel to the outside of the turn. One of the driven axles includes wheel speed sensors mounted at opposite ends of the axle. The controller receives signals from each of the wheel speed sensors to determine an actual differential wheel speed. The predicted speed differential is compared to the actual speed differential and any difference between the two indicates wheel is slippage.

Abstract: A hydraulic device to limit slip can be used in the vehicle's main differential and the vehicle's inter-axle differential. The device includes a cylinder body connected to an input shaft, pistons disposed within radial cylinder bores in the cylinder body, and a cam ring connected to the output shaft, and disposed adjacent the pistons. The cylinder body is generally ring-shaped and has at least one pair of cylinder bores connected by an orifice spaced radially around the cylinder body interior bore. One of the radial cylinder bores in the pair is filled with hydraulic fluid. One piston protrudes from its corresponding radial cylinder bore. The cam ring is also generally ring-shaped having one lobe around its outer circumference per radial cylinder bore pair. As the cylinder body rotates along with the input shaft, the pistons interact with the cam ring lobes. The lobe forces the protruding piston into its corresponding radial cylinder bore.

Abstract: A system for correcting drive wheel slippage in a heavy vehicle includes a front non-drive axle and either a single or tandem rear drive axle with an inter-axle differential with locking capability. Each drive axle also includes a main differential with locking capability. The system further includes a first sensor for measuring the rotational speed of the driveshaft and a second sensor for measuring non-driven wheel speed. A central processor compares the driveshaft speed to the non-driven wheel speed and locks the inter-axle differential of a tandem rear drive axle to drive the front and rear drive axles at the same speed or locks the main differential of a single rear drive axle to drive the first and second driven wheels at the same speed when the ratio of the driveshaft speed signal to the first non-driven wheel speed signal exceeds the predetermined limit. In the tandem configuration, if drive wheel slippage continues, the main differentials of the front and rear drive axles are also locked.