US 11,731,690 B2
Redundant steering system and machines and methods thereof
Edward William Mate, Manhattan, IL (US)
Assigned to Caterpillar Inc., Peoria, IL (US)
Filed by Caterpillar Inc., Peoria, IL (US)
Filed on Feb. 12, 2020, as Appl. No. 16/788,998.
Prior Publication US 2021/0245804 A1, Aug. 12, 2021
Int. Cl. B62D 5/09 (2006.01); B62D 5/30 (2006.01)
CPC B62D 5/091 (2013.01) [B62D 5/30 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A wheeled machine comprising:
a pair of steering cylinders configured to control steering movement associated with the wheeled machine;
a primary power source of the wheeled machine;
a secondary power source;
a first variable displacement pump operatively coupled to the primary power source and configured to output a primary supply of hydraulic fluid to the pair of steering cylinders based on operation of the primary power source;
a second variable displacement pump operatively coupled to the secondary power source and configured to output a secondary supply of hydraulic fluid to the pair of steering cylinders based on operation of the secondary power source;
a first pair of selector valves coupled to the first variable displacement pump;
a second pair of selector valves coupled to the second variable displacement pump; and
a charge circuit coupled to respective control inputs of the first and second pairs of selector valves and configured to selectively supply hydraulic fluid to the control inputs of the first and second pairs of selector valves to stop hydraulic fluid from only one of the first variable displacement pump and the second variable displacement pump from being supplied to the pair of steering cylinders and to provide hydraulic fluid from only one of the other of the first variable displacement pump and the second variable displacement pump to the pair of steering cylinders,
wherein the primary supply of hydraulic fluid and the secondary supply of hydraulic fluid to the pair of steering cylinders are meterless,
wherein the charge circuit includes:
a primary charge sub circuit having a first charge pump,
a secondary charge subcircuit having a second charge pump, and
a control valve arrangement coupled to the control inputs of the first and second pairs of selector valves and selectively coupled to respective outputs of the primary charge subcircuit and the secondary charge subcircuit via an exclusive valve between the primary charge subcircuit and the secondary charge subcircuit.