Braking system for a hydraulic machine

A hydraulic machine comprising a shaft and a casing mounted to rotate relative to each other by means of a bearing, the hydraulic machine comprising:

• first brake elements constrained to rotate with the casing;
• second brake elements constrained to rotate with the shaft;
• the first and second brake elements forming a stack and being configured so as to enable the casing to be constrained to rotate with the shaft when they are put into contact;
• a spring washer mounted to bear against the casing and tending to urge the first and second brake elements in a braking direction, tending to cause the first and second brake elements to be put into contact;
• and
• brake release pistons configured to act on the spring washer in a direction opposing the braking direction;
• wherein
• the brake release pistons comprise a primary brake release piston associated with a primary brake release chamber, and a secondary brake release piston associated with a secondary brake release chamber, said primary and secondary chambers being fluidly connected together and adapted through a common pressurized fluid within each chamber to exert thrust forces respectively on the primary piston and on the secondary piston wherein with the chambers pressurized the primary brake release piston applies a releasing force to the secondary brake release piston and additionally the secondary brake release piston applies a releasing force to compress the spring washer such that the combined forces release act against the spring to the brake elements and allow the shaft to rotate;
• and
• said primary and secondary chambers being arranged in succession along a longitudinal direction of the shaft and extending radially around the shaft in such a manner that projections of the primary brake release chamber and of the secondary brake release chamber onto a plane perpendicular to a longitudinal axis defined by the axis of rotation of the hydraulic machine are overlapping, at least in part.