valve guide shoulder

例句：

1. 1. The engineer used a valveguide to ensure the proper alignment of thepistons.
   工程师使用阀门导向确保活塞正确对齐。
2. 2. The technician adjusted thevalve guide shoulder to improve the flow rateof the oil.
   技术人员调整阀门导向肩部以改善油的流动速率。
3. 3. Duringmaintenance, the technician replaced the valve guideshoulder with a new one.
   在维护期间，技术人员用一个新的阀门导向肩部替换了旧的。