What is the difference between double lead worm reducer and ordinary worm reducer

The difference between the double-lead worm reducer and the ordinary worm reducer is that the left and right sides of the double-lead worm teeth have different leads, while the leads on the same side are equal.Therefore, the tooth thickness of the worm gradually increases or decreases uniformly from one end to the other end of the worm.Therefore, the double-lead worm is also called the variable tooth thickness worm, so the method of axially moving the worm can be used to eliminate or adjust the meshing gap between the worm gear pairs.The meshing principle of the double-lead worm pair is the same as that of the general worm pair. The shaft section of the worm is still equivalent to the basic rack, and the worm wheel is equivalent to the gear that meshes with it.Since the left and right sides of the worm teeth have different pitches, the left and right sides of the teeth have different modules.However, because the tooth pitch on the same side is the same, the meshing conditions are not destroyed, and good meshing can also be guaranteed after the worm is moved axially.
The double-lead worm gear pair is widely used in CNC machine tools with rotary feed motion or indexing motion, and has many outstanding advantages:
1) The double-lead worm gear pair uses the axial movement of the worm to adjust the meshing side clearance. The meshing clearance can be adjusted very small, and the correct meshing relationship can always be maintained. The structure is compact and easy to adjust;
2) The double-lead worm uses a grinding adjustment ring to control the adjustment amount, and the adjustment is accurate, convenient and reliable.For some occasions in the machine tool that require accurate transmission motion, in order to avoid the excessive backlash formed by manufacturing errors and worm gear wear affecting the transmission accuracy, a double-lead worm gear and worm drive mechanism is often used.