Unloading fine tuning device of numerically-controlled drilling machine sliding seat

The invention provides an unloading fine tuning device of a numerically-controlled drilling machine sliding seat. The unloading fine tuning device comprises a fixed sleeve and also comprises an unloading roller mechanism and a loading adjusting mechanism which are arranged in an inner cavity of the fixed sleeve, wherein the unloading roller mechanism comprises a movable sleeve capable of moving upand down, a suspension shaft penetrating through the movable sleeve, a load-carrying bearing, a bearing stop ring and a bearing sleeve; the load-carrying bearing, the bearing stop ring and the bearing sleeve are arranged at the middle part of the suspension shaft; the bearing sleeve is fixed on an outer ring of the load-carrying bearing; the loading adjusting mechanism comprises an adjusting screw, a nut, an elastic part and a stepped shaft capable of moving up and down; the upper part of the elastic part is in contact with the lower surface of a large-diameter part of the stepped shaft; thelower part of the elastic