关键词: 活塞泵；电动真空泵；阀座脱落；热膨胀系数；压装件变形

Abstract: During the endurance test of a certain type of electric motor driven vacuum pump, the piston valve seat falls off. The potential causes of piston valve seat shedding are analyzed using the failure tree analysis method. Review the dimensions of the valve seat before the test. The valve seat and valve seat hole are X-ray inspected. The tolerance zone of the valve seat is analyzed and calculated. The pressure difference between the inside and outside of the valve seat is monitored when the pump is started at low temperature. The temperature difference between the valve seat and the valve seat hole during the cooling process of the pump is monitored. The force distribution and deformation of the valve seat and valve seat hole are simulated and calculated. By analyzing and eliminating these reasons one by one, it is finally determined that the valve seat falling off is caused by uneven deformation of the valve seat hole. For this reason, the valve seat is optimized and improved, and the improved product is verified through simulation calculation and tests. Finally, the problem of valve seat falling off is fundamentally solved.

Key words: piston pump; electric motor driven vacuum pump; valve seat falls off; coefficient of thermal expansion; deformation of pressed parts