Main shaft fixing device, main shaft mounting assembly and bottom door opening and closing mechanism

The utility model discloses a main shaft fixing device, a main shaft mounting assembly and a bottom door opening and closing mechanism, and belongs to the technical field of railway hopper cars. The main shaft fixing device comprises two hoisting assemblies which are oppositely arranged in the axial direction of a main shaft; the hoisting assembly comprises a hoisting plate and a plurality of connecting plates; the first ends of the multiple connecting plates are fixedly connected with the lifting plate, the second ends of the multiple connecting plates are used for being connected with an underframe of the vehicle, and every two adjacent connecting plates in the multiple connecting plates are arranged at an angle; a through groove is formed in the bottom of the hanging plate, and the main shaft is arranged in the through groove in a penetrating mode. According to the main shaft fixing device, the main shaft installation assembly and the bottom door opening and closing mechanism, different bottom door opening