A locking device (200, 200b), comprising: a first flange, the first flange being adapted to be fixed on a first shaft; a second flange, the second flange being adapted to be fixed on a second shaft; a first flange locking structure, the first flange locking structure being used for selectively locking the first flange and the second flange to be adapted to rotate the second flange synchronously with the first flange; characterized in that the locking device is further comprising: a second flange locking structure, the second flange locking structure being used for selectively locking the second flange and the first flange to be adapted to rotate the first flange synchronously with the second flange, wherein the first flange locking structure and the second flange locking structure each comprise: a synchronizing ring (202a, 202b), the synchronizing ring (202a, 202b) being normally connected to the corresponding flange (201a, 201b) to be adapted to rotate synchronously with the corresponding flange (201a, 201b), and the synchronizing ring being slidable relative to the corresponding flange (201a, 201b); and a driving component, the driving component selectively pushing the synchronizing ring (202a, 202b) to slide from an unlocked position to a locked position in an axial direction of the corresponding flange (201a, 201b), wherein when one of the synchronizing rings (202a, 202b) is in the locked position, the two synchronizing rings (202a, 202b) of the first and second flange locking structures (Q1, Q2) are connected to be adapted to rotate the other flange (201a, 201b) synchronously with the flange (201a, 201b) corresponding to the synchronizing ring (202a, 202b), and when one of the synchronizing rings (202a, 202b) is in the unlocked position, the two synchronizing rings (202a, 202b) are separated. a first flange, the first flange being adapted to be fixed on a first shaft; a second flange, the second flange being adapted to be fixed on a second shaft; a first flange locking structure, the first flange locking structure being used for selectively locking the first flange and the second flange to be adapted to rotate the second flange synchronously with the first flange; characterized in that the locking device is further comprising: a second flange locking structure, the second flange locking structure being used for selectively locking the second flange and the first flange to be adapted to rotate the first flange synchronously with the second flange, wherein the first flange locking structure and the second flange locking structure each comprise: a synchronizing ring (202a, 202b), the synchronizing ring (202a, 202b) being normally connected to the corresponding flange (201a, 201b) to be adapted to rotate synchronously with the corresponding flange (201a, 201b), and the synchronizing ring being slidable relative to the corresponding flange (201a, 201b); and a driving component, the driving component selectively pushing the synchronizing ring (202a, 202b) to slide from an unlocked position to a locked position in an axial direction of the corresponding flange (201a, 201b), a second flange locking structure, the second flange locking structure being used for selectively locking the second flange and the first flange to be adapted to rotate the first flange synchronously with the second flange, wherein the first flange locking structure and the second flange locking structure each comprise: a synchronizing ring (202a, 202b), the synchronizing ring (202a, 202b) being normally connected to the corresponding flange (201a, 201b) to be adapted to rotate synchronously with the corresponding flange (201a, 201b), and the synchronizing ring being slidable relative to the corresponding flange (201a, 201b); and a driving component, the driving component selectively pushing the synchronizing ring (202a, 202b) to slide from an unlocked position to a locked position in an axial direction of the corresponding flange (201a, 201b), a synchronizing ring (202a, 202b), the synchronizing ring (202a, 202b) being normally connected to the corresponding flange (201a, 201b) to be adapted to rotate synchronously with the corresponding flange (201a, 201b), and the synchronizing ring being slidable relative to the corresponding flange (201a, 201b); and a driving component, the driving component selectively pushing the synchronizing ring (202a, 202b) to slide from an unlocked position to a locked position in an axial direction of the corresponding flange (201a, 201b), wherein when one of the synchronizing rings (202a, 202b) is in the locked position, the two synchronizing rings (202a, 202b) of the first and second flange locking structures (Q1, Q2) are connected to be adapted to rotate the other flange (201a, 201b) synchronously with the flange (201a, 201b) corresponding to the synchronizing ring (202a, 202b), and when one of the synchronizing rings (202a, 202b) is in the unlocked position, the two synchronizing rings (202a, 202b) are separated.