Totally-enclosed brake

The fully-closed brake comprises a mounting base, a sealing seat and a protective cover which are sequentially, fixedly and hermetically connected with a motor seat, the protective cover is arranged on a motor shaft in a covering manner, a switching frame and a running and parking brake are arranged in the protective cover, and the switching frame is fixedly arranged on the mounting base; the running and parking brake comprises caliper body assemblies which are fixedly installed on the adapter frame and symmetrically arranged on the two sides of the brake disc, brake units are arranged in the caliper body assemblies in a sliding and sealing mode in the axial direction, and brake relieving oil cavities are formed between the sides, close to the brake disc, of the brake units and the caliper body assemblies. The two brake release oil cavities are communicated with each other, and any one brake release oil cavity is provided with an oil port communicated with the outside. Through cooperative use of the braking u