JPS5635725A - Hardening device of gear - Google Patents

Abstract

PURPOSE:To make thermal shrinkage uniform and decrease the strain owing to thermal deformation by expanding a tension mandrel and abutting the same on the inside circumferential surface of the central shaft hole of a gear and hardening the gear in the state that it is held pressed. CONSTITUTION:A tension mandrel 15 is inserted into the central shaft hole 16' of a gear 16 in a red hot state and is placed on a retainer table 10. As a rod 26 is lowered, a holding cover 36, pressing member 32, upper die 33 and gear pressing means 25 lower so that a holding cover 36 adheres colsely onto the 2nd table 11 and a cooling passage 14 and a discharge port 38 communicate, thereby forming a tank for cooling oil. At the same time, the tension mandrel 15 is compressed by the upper die 33 and expands until it abuts on a stopper ring 12. Hence, the gear 16 is automatically centered. Next, fluid pressure is supplied to the 2nd chamber 31, then a cylinder 29 lowers and the jaw part 32' of the pressing member 32 presses to the top face of the gear and this completes setting of the gear 16. In this state, cooling oil is flowed to the cooling passage 14 of the 2nd table 11, whereby hardening is accomplished. When the hardening is finished, the cooling oil is discharged from the discharge port 38 via the passage 14.