Axial piston variable displacement hydraulic devices, such as hydraulic motors, and methods of operating same

An inline hydro-mechanical transmission comprising:

• a fixed displacement pump;
• pump distributor valves arranged to regulate fluid flow to and from the pump;
• an axial piston hydraulic motor comprising:
• a barrel forming a plurality of cylinder bores, wherein the barrel is rotatable about a centerline;
• a plurality of pistons, wherein respective ones of the pistons are slidably maintained within corresponding ones of the cylinder bores;
• a swashplate positioned to interface with the pistons with rotation of the barrel;
• a plurality of motor distributor valves, wherein respective ones of the distributor valves are in fluid communication with corresponding ones of the pistons;
• and
• a valve cam defining a profile, wherein the valve cam is positioned such that the profile interfaces with the motor distributor valves with rotation of the barrel;
• wherein an arrangement of the valve cam profile relative to the motor distributor valves is rotatably adjustable about the centerline of the barrel;
• wherein high pressure fluid from the pump is delivered to the motor via the pump distributor valves.