Product features: stable transmission, compact installation structure.
Additional application: large lead, small transmission torque, high requirement of effective travel ratio, large diameter ratio leads to about 1.2).
Ball screw pair Lead accuracy
Ball screw pairs are divided into positioning (P) and transmission (T) according to the use requirements. The transmission ball screw pair mainly considers the ability and stability of power transmission, while the positioning ball screw pair also puts forward higher requirements for axial displacement control.
The lead accuracy of ball screw is divided into seven grades, as shown in fig-2.
The lead accuracy of ball screw pair is mainly evaluated by four indexes, i.e. the stroke variation within 2 π radian V2 π p; the variation within any 300 stroke v300p; the effective stroke variation VuP; and the effective average travel deviation EP. See Figure 3 and table 1 for details.
Specification and model selection of ball screw bearing:
① Positioning accuracy;
② Through the motor and speed requirements to lead screw bearing;
③ Check the nut size, stroke and relevant screw bearing shaft end data;
④ The axial force and speed are averaged by load and velocity distribution (acceleration and deceleration);
⑤ Preloading through average axial force;
⑥ Life expectancy, axial load, speed, dynamic rated load;
⑦ Basic dynamic rated load, lead, critical speed and DMN value limit the outer diameter of lead screw bearing and nut form;
⑧ Outer diameter, nut, preloading, load rigidity (machine design);
⑨ Ambient temperature, total length heat change and accumulated lead of nut;
⑩ Screw bearing rigidity, thermal displacement pre tension;
⑪ Machine tool high speed, temperature rise time, screw bearing specifications, motor drive torque and specifications.