Calculation of allowable speed of ball screw

When the lead screw runs at a resonant speed, it is called the dangerous speed. The influence of resonance is very great, usually cause poor processing products, and even damage machinery, so we must try to avoid the motor speed and natural frequency of the lead screw resonance, generally at the dangerous speed of 80% below the allowable speed.

Allowable speed calculation formula:

n=f*dr/L∧2*10∧7 (rpm) n: Allowable speed (rpm) dr: screw shaft Bottom diameter (mm) L: Mounting distance (mm) (relative distance between the two ends of the screw) f: The coefficient determined by the mounting method of the ball screw (propping-propping-fixed f=9.7 Propping-fixed f=15.1 fixed-fixed f=21.9 fixed-free f=3.4)

If the allowable speed does not meet the design requirements, support can be installed in the middle to improve the natural vibration frequency of the screw, to improve the allowable speed.

dm.n value of ball screw:

dm is the pitch circle diameter of the screw, n is the * allowable speed of the ball screw, so dm.n is the nominal speed of the ball screw. It is a key factor affecting the noise, operating temperature, life and circulation system of ball screw. In general, the restrictions are as follows:

Precision: dm.n≤70000

Rolling grade: dm.n≤50000

However, with the continuous development of technology, dm.n value is no longer subject to this limitation.