备份环形状类似垫圈，用途为防止密封件遭到挤压。

Back-up rings are washer-like devices that are used to prevent a seal from extruding through any gaps while under pressure.

youdao

备份环形状类似垫圈，用途为防止密封件遭到挤压。

Back-up rings are washer-like devices that are used to prevent a seal from extruding through any gaps while under pressure.

youdao