The utility model discloses a sliding sleeve screw-down mechanism which comprises a frame body
assembly, a guide sleeve, an ejector rod, a first linear driving mechanism, a second linear driving mechanism, an ejector column and a third linear driving mechanism. A guide groove is formed in the frame body
assembly, and the guide sleeve is vertically connected into the guide groove in a sliding mode. According to the utility model, after the two sliding columns and the sliding sleeve are put into the pushing sleeve, the two sliding columns and the sliding sleeve can be pushed to a position right above the guide sleeve by the second linear driving mechanism; under the action of the first linear driving mechanism, the ejector rod can move upwards so as to enable the two sliding columns to move upwards, and meanwhile, the ejector rod can drive the guide sleeve to move upwards through the first spring so as to enable the sliding sleeve and the two sliding columns to move upwards together; and under the action of the third linear driving mechanism, the pressing plate can press the sliding sleeve downwards, so that the sliding column at the upper part is exposed out of the sliding sleeve, the sliding sleeve can be pressed downwards automatically, and the
friction sensitivity can be measured automatically.