| 摘要 |
PURPOSE:To improve strength of a trunnion by providing three journals on the outer diameter face of a boss member at intervals of 120 deg., and forming circular-arc thefts on an inner diameter face of the boss part, that is, on inner faces of cylindrical parts between journals. CONSTITUTION:Trunnion material A' is provided with a boss member 1 and three journals 2 formed on the outside thereof at intervals of 120 deg.. On the inner diameter face of the boss member 1, that is, inner faces of cylindrical members 4 between the journal forming portions, are formed thefts 5 which are circular arcs, narrowed gradually from the central parts toward both ends. The sizes of the thefts 5 approximately correspond to a contract amount of the cylindrical members 4 at the time of heating/cooling. In this arrangement, the inner diameter face 3 of the boss member 1 forms approximately an exact circle due to cooling after hardening of the trunnion material A'. A second shaft is then press-fitted inside the boss member 1 and thereby tensile stress is evenly applied to the whole inner diameter face of the boss member 1 to improve the strength of the trunnion. |
