As a elementary piece of lifting equipment, screw jack is usually used for transmission of 90 degree between the crisscross shafts. It is of compact structure, small volume, light weight, easy installation, high reliability, long lifespan and so on assets. It is widely used for mechanism, construction, metal industry, vehicle production line, water conservancy equipment, military and so on. The screw jack mostly consists of speed reducing parts and lifting and lowering parts. The worm shaft is the speed reducing component which place the most important part of usability of the screw jack.
Screw and nut are the most important parts of the screw jack which are the common parts of the linear motion. It is difficult to avoid the gap between the screw and nut, specially after using a while as the abrasion between the worm gear and screw will enlarge the gap, lowering the working efficiency of the position accuracy. This is why the gap problem between the worm gear and screw becomes the most important part of all during production and maintaining process. It is necessary to eliminate the gap between the worm gear and screw. Besides fabrication, how to reduce the gap to enhance the positioning accuracy when we use? Nosen will introduce you some useful methods.
Axial end play compensation
First of all, the vertical tolerance between the bearing locating end face of the main shaft and central line of the main shaft and its place should be measured. Then the round end play tolerance on the pushing bearing end face and its final biggest movement of the bearing end face at top place can be measured. It can reduce the tolerance of the radial end play.
Like gears and worm gears, the round end play on the outer circle of the gear and the axial of the component assembly part should be measured first, confirming their top place separately. To adjust the top place of both radial round end play when you assemble, making it at the direction over 180 degree to eliminate the tolerance of the radial round end play mutually. The top place of shaft neck radial round end play and the bottom place of the ball bearing internal whole radial round end play can be assembled at the same place when you assemble.
Radial round end play compensation
As the components of the shafts, to reduce the radial round end play at the former place of the main shaft, you can place the biggest radial round end play point separately generated by the front/back bearing at the same side of the central line which is in the dimension of the same shaft. Besides, the tolerance of the front shaft should be less than the back ones. Its capacity is way bigger than the crisscross shaft bevel gears.
Assembly tolerance compensation
Tolerance compensation is a phenomenon that the components tolerance eliminate mutually at some point by assemble them up. It is a method to make sure the moving orbit accuracy of the equipment. Displacement compensation and comprehensive compensation are the two common compensating methods in mechanical equipment maintaining. The displacement compensation of screw jack is usually used for tolerance compensation at single accuracy, making it easy to assemble the bottom place of pushing bearing round end play together. Screw jack gap can be eliminated by the anti-gap device which is specially design. If you have strict requirement on the screw jack accuracy, you are welcome to consult to Nosen about the screw jack anti-gap details.