Valve stem seal

摘要

To provide a valve stem seal 1 of the structure which is excellent in mechanical strength in response to the high output of an internal combustion engine without causing difficulty of manufacture. A valve stem seal includes a mounting ring 11 arranged so as to surround the outer periphery of a valve guide 3 protruding from a cylinder head 2, a seal lip 12 integrally provided at one end of the mounting ring 11 and slidably brought into close contact with the outer peripheral surface of a valve stem 4 which is inserted through the valve guide 3 and biased in the axial direction by a valve spring 5, a spring receiving ring 14 arranged at the outer periphery of the mounting ring 11 and pushed against the cylinder head 2 by the valve spring 5. The spring receiving ring 14 has a rigidity higher than the mounting ring 11, and has an internal diameter portion locked to a locking groove 11c formed at the outer peripheral surface of the mounting ring 11, and, a groove shoulder of the locking groove 11c on the side of the seal lip 12 is formed with a deformable projecting portion 11e having a diameter larger than the internal diameter of the mounting ring 11 and permitting the internal diameter portion of the spring receiving ring 14 to axially pass therethrough.