| 摘要 |
A piston head structure in which a piston head made of a ceramic is firmly secured to the top portion of a metallic piston body through the medium of a metallic ring fitted to the lower part of the piston head. In assembling, the ceramic piston head to which the metallic ring is fitted beforehand is secured to the top portion of the piston body by a shrink fit or, alternatively, the assembly of the ceramic piston head and the metallic ring is inserted to the metallic material of the piston body during casting of the latter, and the cast piston body is then subjected to necessary mechanical processing. In this structure, the separation of the piston head from the piston body is prevented due to the close fit of the ceramic piston head and the metallic ring to the metallic piston body. Such a fit prevents separation even when the piston body is expanded due to the heat generated during operation of the engine. In addition, the ceramic piston head is protected by the metallic ring against any external force which acts to cause a cracking or breakage of the ceramic piston head, during the production of the piston.
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