A traveling drive device for a dump truck is provided with an axle housing mounted to a vehicle body, a wheel mounting tube rotatably provided on the outer periphery side of the axle housing, a disk holding cylinder provided on the axial outside of the wheel mounting tube, a brake disk mounted to the disk holding cylinder, and a brake device for applying braking to the brake disk. The disk holding cylinder is configured by a cylindrical body to be mounted to the wheel mounting tube and a plurality of disk mounting legs provided on the cylindrical body. A plurality of U-shaped projections are provided on the outer periphery side of the brake disk at positions corresponding to the respective disk mounting legs. A recessed groove which fits on the disk mounting leg so as to hold a distal end thereof is provided in each of the U-shaped projections.

A safety apparatus for a vehicle battery and a method for operating the same capable of preventing accidents such as fire and battery explosion are provided. The safety apparatus includes a fixed housing that is fixed to a vehicle body and a movable housing that is movably disposed in the fixed housing to move due to external impact. An impact sensor is disposed within the fixed housing configured to be fractured due to the movement of the movable housing and an elastic member is configured to provide a restoring force to the movable housing.