Clutch brake steering control
AssigneeCaterpillar Inc.
InventorsJames P. Mueller, Weldon L. Phelps
Life of this patent
Estimating the term…
Abstract
Clutch-brake steering systems are known to operate on track vehicles which are highly reliable and cost effective, but lacked the fine degree of controllability found in the more expensive differential steering. An electronically controlled clutch-brake steering control apparatus provides control signals to electrohydraulic proportional valves for accurately modulating the control pressures of a set of steering clutches and brakes. A pair of sensors deliver signals, which are indicative of track speed, to the control apparatus. The apparatus acts to adaptively adjust selected ones of the valves to maintain a desired track speed differential. Thus, the controllability of the clutch-brake steering system is enhanced to effectively compete with more expensive and complex systems.
Claims11
In a vehicle having a pair of tracks in which driving force is applied to the tracks thereof, including clutch and brake systems associated respectively with the tracks of each side thereof and responsive to a source of fluid pressure for steering of the vehicle, each clutch and brake system comprising a clutch alternately engageable and disengageable to respectively connect and disconnect the driving force applied to the track of the vehicle, and a brake alternately actuatable and releasable to respectively brake and release the track of the vehicle, a control apparatus for the clutch and brake steering system comprising:
- clutch valve means for controlling the fluid pressure delivered to said clutch in response to receiving an electrical control signal;
- brake valve means for controlling the fluid pressure delivered to said brake in response to receiving an electrical control signal;
- means for determining a desired velocity differential between said tracks;
- means for delivering first and second signals correlative to the respective velocities of each of said tracks;
- processing means for receiving said first and second track velocity signals, determining the differential therebetween, comparing said determined and desired velocity differentials to determine the differential error, delivering a control signal to the clutch valve means of one of the tracks in response to the error being less than a preselected setpoint, and delivering a control signal to both the clutch and brake valve means of said one of the tracks in response to the error being greater than the preselected setpoint.
Dependencies are inferred from the claim text.