Main roller with protective structure

The utility model relates to a main roller, in particular to a main roller with a protective structure. The main roller comprises a main shaft, a push disc clutch is arranged on the main shaft, a ball bearing is installed on the main shaft on one side of the push disc clutch, a bearing box A is arranged on the ball bearing, a roller bearing is installed on the main shaft on the outer side of the ball bearing, and a bearing box B is arranged on the roller bearing. The bearing box A and the bearing box B are each provided with a disc-shaped protective cover through a fixing bolt, and the protective cover on the bearing box A is fixedly connected with the push disc clutch through a fixing bolt. The main roller can shield the push disc clutch, so that it can be guaranteed that mud or drilling fluid is not prone to leaking into the push disc clutch, and normal operation of the main roller is guaranteed; the ball bearing and the roller bearing can be filled with lubricating liquid through the lubricating pipe; the