摘要:
A piston seal (8) of a disc brake (20) can stabilize the amount of rollback of a piston (5) by reducing thermal expansion and a decrease in modulus of elasticity of the piston seal (8) caused by an increase in temperature, thereby preventing a driver from feeling that the brake operation is unnatural. The piston seal (8) is formed of a rubber composition in which at least 100 parts by weight or more of carbon black is added to 100 parts by weight of ethylene propylene rubber.