Drilling Tool Bearing and Drivetrain Assembly

A system comprising:

• a drill string;
• a motor assembly coupled to the drill string through a rotary shouldered connection, the motor assembly including
• a power section stator having a first end, a second end, and an internal cavity passing therethrough, and
• a rotor assembly positioned and fully encased in the internal cavity, the rotor assembly including a power section rotor having rotor lobes to cooperate with one or more stator lobes of the power section stator, a drivetrain operably coupled to the power section rotor, and a bearing set, wherein the power section rotor is positioned at the first end within the internal cavity of the power section stator, and wherein the power section rotor, the drivetrain, and the bearing set are fully encased in the internal cavity of the power section stator;
• and
• a drill bit coupled to the drivetrain through a driveshaft.

A method of operating a motor in a well drilling operation, the method comprising:

• loading a rotor assembly into a first end of an internal cavity of a power section stator, the rotor assembly including a power section rotor, a drivetrain operably coupled to the power section rotor, and a bearing set, such that the rotor assembly is fully encased in the internal cavity of the power section stator, to construct a motor assembly;
• coupling the motor assembly to a drill string;
• introducing a drilling fluid into a second end of the internal cavity of the power section stator;
• and
• forcing the drilling fluid through a cavity between the power section stator and power section rotor with sufficient pressure to cause the power section rotor to rotate relative to the power section stator to provide a torque force to a drill bit coupled to a driveshaft coupled to the drivetrain.