expansion spring

例句：

1. 1. The expansion spring is responsiblefor the automatic opening of the door whenit's opened.
   膨胀弹簧负责自动打开门。
2. 2. The expansion spring is a crucialcomponent in many mechanical systems.
   膨胀弹簧是许多机械系统中的关键部件。
3. 3. Theexpansion spring was replaced afterseveral years of use due towear and tear.
   由于磨损，膨胀弹簧在几年后被更换了。