There are two kinds of circulation modes used in ball screws: outer and inner circulation.
The ball is sometimes called an outer loop when it is disengaged from the screw in the course of the cycle; the constant contact with the lead screw is called the internal circulation. Each round loop of the ball is called a column, and the number of lead contained in the closed loop of each ball is called the number of turns. Each nut of the internal circulation ball screw has 2 columns, 3 columns, 4 columns, 5 columns, etc. each column has only one circle, and the outer loop has 1.5 rings, 2.5 rings and 3.5 rings each.
Outer circulation: the outer circulation is the ball, after the circulation process is finished, the screw nut or the outer pipe of the nut is returned to the screw rod, and the nut is re entered into the cycle. The main means of return of the outer circulation ball screw nut are the end cap type, the pipe inserting type and the spiral groove type. The commonly used external circulation methods are: (a) end cover type; (b) intubation type; (c) spiral groove type. The outer circular ball screw outer circulation structure and the manufacturing process are simple and widely used. The disadvantage is that it is difficult to smooth the raceway joints and affect the stability of the raceway.
Inner circulation: the inner circulation adopts the reverser to realize the ball circulation, and there are two kinds of reverser. The size of the outer groove and the slot on the nut of the reverse device require high dimensional accuracy.
