| 摘要 |
PURPOSE:To open and shut an intake/exhaust valve without shock load, and increase it's durability and sealability by setting sealing divided along the circumferential direction at the opening part to the combustion chamber of the intake/ exhaust port, and spring-energizing it inwardly. CONSTITUTION:Stepped seal-ring insertion hole 4 is formed in the lower ceramic plate 3 which is attached to the underside surface of the cylinder head 1, at the correspondent position to the port 2. Several spring insertion grooves 5 are formed in outward part of the hole 4, along the diametral direction of the hole 4. In the insertion hole 4, ceramic seal-ring 6 which is divisible into two parts is inserted and energized radially/inwardly by springs 7 held in the insertion grooves 5. Next, umbrella-shape part 8a of valve 8, which consists of ceramic umbrella-shape part 8a which has guide 19 integrally, and metallic stem part 8b, is put into the seal-ring 6. Then, the sliding surface between umbrella-shape part 8a and seal-ring 6 is functioned as gas seal surface. |
