oil-ring lubrication油环润滑
oil ring lubrication油环滑润;油环润滑
ring lubrication bearing环圈润滑轴承;油环润滑轴承
piston ring lubrication活塞环润滑
oil ring self-lubrication油环自动润滑
lubrication ring润滑油杯;润滑油环
Low pressure lubrication Seal Ring滑油低压封圈
self-lubrication piston ring自润滑活塞环