The difference between a Ball Splines and Ball Screws
Both ball splines and ball screws rely on ball to achieve high efficiency in mechanical transmission, but they differ greatly in structure, function and application scenarios. Here's a detailed comparison:
1.Structural differences
Ball splines
Composition: by a spline shaft, spline sleeve (spline nut), steel balls, fixer and a sealing gasket. The surface of The spline shaft surface is machined with a spiral or linear orbit in which the ball circulates to achieve axial movement and circumferential positioning.
Structural features:
High-torque ball splines has three rolling surfaces uniformly arranged at a 120° angle in the outer ring of the spline shaft. Six rows of load-bearing steel balls were installed to automatically determine the rotation centre. During reversal, the load is borne by the opposite row of steel balls.
Medium-torque spline shafts has two to three protrusions and four to six rows of steel balls. The fixer ensures the entire row circulates, preventing the ball from falling off, even if the shaft is withdrawn. Rotary ball splines (such as LTR) have angular contact with steel ball roll surfaces on the outer diameter of the spline nut to form support bearings, which are both miniaturization and lightweight.
Ball Screw
Composition: composed of screw shaft, nut, steel balls, preload plate, deflector plate and dust collector. The screw is machined with a spiral groove into which the steel balls can be placed. The nut is fastened around the screw and the rolling motion of the steel balls converts the rotation motion to the straight line motion.
Structural features:
Traditional structures are divided into two types: internal recirculation (circular/elliptical deflectors) and external recirculation (insert tubes). More than 10 different configurations have subsequently developed, including end caps and cover plates.
Preload adjustment eliminates axial play and increases rigidity. Internal precision machining and a strict quality control system ensure performance.
2. Differences in function and application
Ball Splines
Function: Mainly used to connect two axes, so that torque transmission and axial movement between the rotation motion, while maintaining circumferential positioning. Application:
Suitable for high speed, largetorque transmission such as industrial robot columns, robotic arm, automatic loader and tire building machines.
Suitable for high sensitivity automation equipment requiring high reliability, such as semiconductor packaging, placement equipment, medical devices, etc..
Suitable for connecting the crankshaft and camshaft of automobile engine for precise alignment and torque transmission.
Ball Screw
Function: To convert rotary motion into straight line motion or straight line motion into straight line motion to achieve high precision position control.
Application:
CNC machine tool worktable movement, industrial robot joint drive and automatic equipment lifting device.
Suitable for linear transmission system which requires precise position control in machinery manufacturing, automation equipment and so on.
