S-cam brake

An S-cam brake comprising:

• a brake chamber to which compressed air is supplied;
• a slack adjuster rotatably connected to the brake chamber;
• an S-cam unit having an S-cam connected to and rotating around the slack adjuster;
• and
• a drum having a lining generating braking force with widening according to rotation of the S-cam,
• wherein the brake chamber comprises:
• an upper housing having an air supply port through which the compressed air is introduced;
• a lower housing coupled to the upper housing to form an internal space;
• a diaphragm having edges fixed to the upper housing and the lower housing and deformed by the compressed air;
• a piston disposed to contact the diaphragm and move linearly;
• a piston push rod extending from the piston and having one end connected to the slack adjuster;
• and
• a spring having one end supported by the piston and the other end supported by the lower housing,
• wherein a thickness of the upper housing is greater than a thickness of the lower housing,
• wherein a bottom surface of the upper housing comprises a channel connected to the air supply port, and
• wherein the channel is formed of a groove having a ‘+’ shape, in bottom view.