Recirculating Ball Screw

Table of Contents

A recirculating ball screw consists a screw, a nut and a series of balls.

The main difference between a recirculating ball screw and a power screw is that in former the sliding friction gets replaced by rolling friction.

Since rolling friction is very less than sliding friction recirculating ball screw has very high efficiency of power transfer.

The threads of screw and nut in recirculating ball screw are semicircular so that they can accommodate rolling balls.

Recirculating ball screw is also known as ball bearing screw or simply ball screw.

There is almost no heat generation in recirculating ball screw due to negligible friction and they can be used at very high speeds up to 10 m/min.

Advantages of recirculating ball screw

Compared to power screw they offer following advantages.

They have very high efficiency (approx. 90%), compared to power screw (approx. 40%)
No stick and slip phenomenon which results in durability
It is virtually wear free
They require Less starting torque
No heat generation during operation
They can be used for high speed operations
They can be easily preloaded to eliminate backlash
They have very smooth and noiseless operation
They have high reliability and durability
Their load carrying capacity is more than power screw of the same size

Disadvantages of recirculating ball screw

Compared to power screw they offer following disadvantages.

They are much more costly
Buckling of screw is serious problem at critical speed
They require high degree of cleanliness
They require thin film lubrication for satisfactory operation
They can have vibrations
They require periodic overhauling to maintain their efficiency
They do not have self-locking properties

Applications of recirculating ball screw

Machine tools controls
Used in robotics where precise movement is vital
Hospital beds adjusters
Aircraft landing gear retractors
X-Y recorders of CNC machines
Power actuators
Automobile steering gears

Also read:

What is residual stress?

What is hot and cold working of metals?

What are fiber reinforced plastics?

What are ceramics?

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