求翻译：齿轮端面和端盖之间的间隙为轴向间隙，轴向间隙引起的泄漏为轴向泄漏。因为泄漏途径短，泄漏面积大，所以轴向泄漏的泄漏量最大，可占总泄漏量的75%~80%。轴向间隙大，泄漏量就大，容积效率降低；轴向间隙过小，虽然泄漏量减小，但会使机械摩擦损失增加， 从而使机械效率降低。因此齿轮泵必须严格控制轴向问隙，保证总效率不能太低。是什么意思？

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gear end face and end cap for the gap between axial clearance, axial clearance for the axis leak to leaks. Since leakage paths short, the leak is large in size, so the leakage of the maximum amount of leakage, the leakage of the total 75 percent to 80 percent. Axial clearance, on the amount of leaka

Gear end clearance between shaft and end caps to the gap, leakage for axial leakage caused by axial clearance. Because the leak means shorter, resulting in leakage of large a