| 摘要 |
PURPOSE:To make the interval between a housing and a rotary sleeve constant by forming said housing with an aluminum alloy while forming said rotary sleeve with a spherical graphite cast iron consisting of an inclusion structure of bainite and retained austenite. CONSTITUTION:Vanes 8 are projected out of the outer peripheral face of a rotor 5 and brought into contact with the inner peripheral face of a rotary sleeve 4. The rotary sleeve 4 is formed with a spherical graphite cast iron, which is subjected to austempering to make a mix-structure of bainite and retained austenite. The housing 1 is formed with an aluminum alloy. Thereby, the constant state of the interval between the housing and the rotary sleeve can secured. |
