How to properly adjust the clearance of the screw jack?

I. Shift compensation

Shift compensation is often used for error compensation of single accuracy.

1.Compensation of axial runout: Firstly, the perpendicularity error of the bearing locating surface and spindle centerline on the spindle should be measured and its directional position: then the end face circular runout error of the thrust bearing should be measured and its highest point position finally the highest point of the bearing locating surface should be shifted so that the lowest point of the end face circular runout of the thrust bearing can be assembled together to reduce the amount of error of axial runout.

2. Radial circular runout compensation: For parts assembled on the shaft, such as gears, worm gears and other parts, the radial circular runout value of the part on the outer circle and the shaft at the part assembly should be measured first, and determine the location of the highest point respectively. When assembling, the highest point of the two radial circular runout will be moved and adjusted so that it is in the direction of 180° difference to offset part of the radial circular runout error with each other. In order to reduce the radial circular runout value of the front end of the spindle, you can make the front and rear bearings at the respective maximum radial circular runout point is located in the same axial plane on the same side of the spindle centerline, and make the error value of the front bearing smaller than the error value of the rear bearing.

The worm gear has a linear contact between the two meshing tooth surfaces, and its load-bearing capacity is much higher than that of the staggered shaft helical gear mechanism.

Screw jack drive is equivalent to screw drive, multi-tooth meshing drive, so the transmission is smooth and very low noise.

The worm gear box of the screw jack is self-locking. When the lead angle of the worm is smaller than the equivalent friction angle between the teeth of the meshing wheel, the mechanism is self-locking and can achieve reverse self-locking, i.e., only the worm can drive the worm wheel, and the worm cannot be driven by the worm wheel. As in the case of the self-locking worm mechanism used in heavy machinery, its reverse self-locking can play a role in safety protection.

Second, the error compensation method

Error compensation is the parts of their own errors through the appropriate assembly, to produce a certain degree of mutual offset phenomenon, in order to ensure the accuracy of the equipment movement trajectory of an adjustment method. In mechanical equipment maintenance, the commonly used error compensation methods are shift compensation and comprehensive compensation.