1. Double push-free mode As shown in Figure 8-8a, one end of the screw is fixed and the end is free. The fixed end bearing bears both axial force and radial force. This type of support is used for short lead screws with small strokes.

2. Double push and one support mode As shown in Figure 8-8b, one end of the screw is fixed and the other end is supported. The fixed end bearing bears both axial force and radial force; the supporting end bearing only bears radial force, and can make a small amount of axial float, which can avoid or reduce the bending of the lead screw due to its own weight. At the same time, the thermal deformation of the lead screw can freely extend to one end.

3. Double push and one double push mode As shown in Figure 8-8c, both ends of the lead screw are fixed. The fixed-end bearing can bear axial force and radial force at the same time. This kind of support method can apply appropriate pretension to the screw, improve the support rigidity of the screw, and can partially compensate for the thermal deformation of the screw.

4. The transmission mode of screw fixing and nut rotation is shown in Figure 8-8d. At this time, the nut rotates while moving axially along the fixed screw: Because the screw does not move It can avoid the limitation of the critical speed, and avoid all kinds of problems that appear when the slender ball screw is running at high speed. The nut has small inertia, flexible movement and high achievable speed. In this way, a larger pretension force can be applied to the lead screw, the supporting rigidity of the lead screw can be improved, and the thermal deformation of the lead screw can be compensated.

The installation of the ball in the ball screw bearing

Clean the screw and the ball, use a thinner lubricant such as a liquid helper as lubrication, and the screw nut is sleeved on the screw Put the balls into the nut as much as possible, and install the nut when there is a gap. Repeat until you play. The higher the level of the screw, the more balls that can’t be installed. Generally, the domestic screw can be used to install the balls. Put it in, and finally fill the nut with dry oil. Pay attention to turning the nut when filling the oil. This can generally take a while.