Detachable displacement box of bridge modular expansion device

The utility model relates to a detachable displacement box of a bridge modular expansion device. The detachable displacement box comprises a semi-closed box body formed by assembling a lower box body and a cover plate. A middle transverse steel beam with one end extending out of an inner cavity of the semi-closed box body is arranged in the semi-closed box body, and a displacement control spring is arranged between the other end of the middle transverse steel beam and the rear end of the inner cavity of the semi-closed box body. A lower pressure-bearing support, a first front permanent check block and a first rear detachable check block are arranged between the bottom of an inner cavity of the semi-closed box body and the bottom of the middle transverse steel beam, and the first front permanent check block and the first rear detachable check block are located at the two ends of the lower pressure-bearing support respectively. An upper damping spring, a second front permanent check block and a second rear deta