High-power heavy-load planetary gear back-to-back test bench

The invention discloses a high-power heavy-load planetary gear back-to-back test bench, and relates to the field of planetary gear tests. The invention aims to solve the problems that the machining cost of a transmission shaft is high and a planetary gear box cannot be tested in a marine environment in the conventional planetary gear test bed. A driving device, a first coupler, a speed increaser, a second coupler, a rotating speed torque meter and a planetary gearbox back-to-back closed power system are sequentially connected, an axial positioning protrusion is coaxially sleeved with a clamping groove body, and a clamping assembly is embedded in an axial positioning groove. The clamping groove body is sleeved with the shaft section, the clamping groove body and the axial positioning protrusion are clamped through axial displacement provided by the clamping assembly, and the clamping groove body generates radial displacement under the axial pushing effect of the clamping assembly and is connected with the axia