Pressure balancing of rotating control piston of generator transmission

A speed changing transmission assembly, comprising:

• an input shaft:
• an output shaft;
• and
• one or more clutch assemblies to selectably engageable with the output shaft, each clutch assembly including:
• a clutch pack;
• a rotating control piston selectably engageable with the clutch pack via movement of the control piston along an axis of rotation of the control piston, the control piston including:
• a piston member engageable with the clutch pack;
• a cover plate installed into the piston member to define an enclosed volume;
• an axially fixed chamber divider disposed in the enclosed volume to divide the enclosed volume into a control pressure chamber and a pressure balancing chamber;
• wherein both the control pressure chamber and the pressure balancing chamber are filled with hydraulic fluid;
• and
• wherein the control piston is moved between a disengaged position and an engaged position via modulation of hydraulic pressure in the control pressure chamber;
• and
• wherein the control pressure chamber and the pressure balancing chamber are configured to exert equal and opposite forces on the rotating control piston due to balancing of centripetal forces attributable to the rotation of each hydraulic fluid-filled chamber.

An aircraft, comprising:

• a gas turbine engine;
• one or more accessory components operably connected to the gas turbine engine, and driven by rotational energy diverted from the gas turbine engine;
• a speed-changing transmission assembly configured to convert the rotational energy diverted from the gas turbine engine to a speed range usable by the one or more accessory components, the transmission assembly including:
• an input shaft operably connected to the gas turbine engine:
• an output shaft operably connected to the one or more accessory components;
• and
• one or more clutch assemblies to selectably engageable with the output shaft, each clutch assembly including:
• a clutch pack;
• a rotating control piston selectably engageable with the clutch pack via movement of the control piston along an axis of rotation of the control piston, the control piston including:
• a piston member engageable with the clutch pack;
• a cover plate installed into the piston member to define an enclosed volume;
• an axially fixed chamber divider disposed in the enclosed volume to divide the enclosed volume into a control pressure chamber and a pressure balancing chamber;
• wherein both the control pressure chamber and the pressure balancing chamber are filled with hydraulic fluid;
• and
• wherein the control piston is moved between a disengaged position and an engaged position via modulation of hydraulic pressure in the control pressure chamber;
• and
• a plurality of control pressure orifices fluidly connected to the control pressure chamber through which hydraulic fluid enters and exits the control pressure chamber.