AKASAKA.GH-R3T-108.520 机械密封 AKASAKA.GH-R3T-108.524 弹簧座碳钢 SS400 AKASAKA.GH-R3T-108.531 O 型圈橡胶 VITON AKASAKA.GH-R3T-108.532 油封橡胶NBR AKASAKA.GH-R3T-108.540 滚珠轴承 SUJ2