Internally drained hydraulic motor

A hydraulic motor that can be operated in both directions, the hydraulic motor comprising two two-way hydraulic ports each of which can be connected, selectively depending on the direction of rotation in which the motor is to be actuated, either to a source of pressurized liquid in order to act as a feed port for the hydraulic motor, or to a device for collecting the liquid at a lower pressure in order to act as a hydraulic motor return port, the hydraulic motor comprising a drain port communicating with an interior space of the motor case, which comprise

• an intermediate pipe into which the drain port of the case opens,
• a first non-return valve positioned between the intermediate pipe and a first two-way hydraulic port and able to open under the effect of a positive pressure differential between the intermediate pipe and the first two-way hydraulic port;
• and
• a second non-return valve positioned between the intermediate pipe and a second two-way hydraulic port and able to open under the effect of a positive pressure differential between the intermediate pipe and the second two-way hydraulic port.