The utility model relates to the technical field of drum brakes, and discloses a self-energizing
drum brake which comprises a back plate, a connecting hole is formed in the back plate, the back plate is fixedly connected with a transmission shaft through the connecting hole, a
brake drum is detachably installed on the back plate, a first pin rod is fixedly installed on the front side of the back plate, and a first
brake shoe is rotatably installed on the first pin rod. The
brake device has the advantages that the bottom ends of the first
brake shoe and the second
brake shoe can be controlled to be far away from each other, the two brake pads abut against the brake drum, the braking purpose is achieved, the L-shaped connecting rod can be controlled to rotate through unfolding of the first
brake shoe, then the top supporting rod is driven to push the second brake shoe to be tightly attached to the brake drum, and braking is achieved. The
extrusion force of the
brake pad on the brake drum is enhanced, the contact area of the
brake pad and the brake drum is increased, the
brake force is enhanced, meanwhile, the abrasion of the
brake pad is more uniform, and the service life of the brake pad is prolonged.