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What is a Precision Lock Nut?
Precision lock nuts are a bearing accessory for screw drives. They help achieve a defined axial preload in axial angular contact ball bearings for screw drives. Such lock nuts are different from common fixing-lock nuts. Due to their perfect design, they easily negotiate the increasingly dynamic demands and power densities of modern machine designs.
High-quality self-locking nuts show their strength when things are really moving. They ensure there is optimum concentricity on spindles. Their functional support systems, such as the load thread, locking thread, and end face, are inseparable components of the lock nut and are produced in a single setting with high precision. The diaphragm lock helps achieve precision when you use a lock nut for any application.
Features of Precision Lock Nut
Their main features are:
- Rigidity and excellent load capacity
- Perfect balance and high precision caused by perpendicularity between the threading and the surface trodden by the locknut.
- Precise, safe, resistant, and balanced fixing.
- Security washers are not required.
- You can use them several times.
How do Precision Lock Nuts work?
We use them for adjusting, preloading, and securing bearings, gears, and other power transmission products to shafts and spindles that usually have a high degree of stiffness. They are also known as bearing locknuts because locknuts are manufactured as per standard bearing sizes.
They have inbuilt internal threads and sturdy faces that provide effective metal-to-metal locking without distortion. It would be best if you had a spanner wrench to secure lock nuts. You tighten right-handed threads with clockwise turns. Similarly, you tighten the left-handed threads with counterclockwise turns.
Precision lock nuts have a locking mechanism that secures them to the shaft. It usually includes set screws, clamping screws, shoes, and resilient rings. Setscrews are either present on the periphery or the face of the locknut. In both cases, you use setscrew to secure the locknut thread to the shaft by distorting the threads. Setscrews on the face of the locking section eliminate the thread clearance of the locknut.
These lock nuts have a clamping and a locking section with a radial groove separating them. You secure lock nuts with shoes by tightening set screws on the periphery of the locknut. While in the resilient ring locking mechanism, you put nylon or other similar material between the thread flanks. Ideally, it would be best to use a lock washer or locking adhesive without an integral locking feature.
Specifications of Locknuts
Lock nuts are made of different materials – hardened alloy steel, stainless steel, or heat-treated alloy steel with a coating of black oxide finish for corrosion resistance. Their specifications include the following:
- Major thread diameter.
- Threads per inch.
- Threads per pitch.
- Locking face diameter.
- Overall locknut diameter.
- Locknut width.
- Bearing bore size, either in millimeters or inches.
- Holes and slots are situated on the periphery of the Precision Lock Nuts
Pros and Cons of Using Ball Screw lock Nuts?
A ball screw is a mechanical device that is an anti-friction nut. These nuts are used to convert rotational motion into linear motion. They have a long threaded shaft fitted with ball bearings to withstand significant stress and weight while minimizing friction. A normal ball screw has both a screw and a nut. The screw and nut are fixed to allow ball bearings to roll between them.
During the rotation of ball screws, the ball bearings move to the return system before changing direction. The ball screw first appeared in1920s. They have applications in various manufacturing processes, including airplanes, missiles, automobiles, 3D printers, and machines.
What is the difference between Ball Screw lock nuts and Lead Screws?
Ball screw lock nuts and Lead screws look similar, but only the former is fitted with ball bearings. Ball screws come with a nut in which ball bearings circulate to support the load and reduce friction. In lead screws, the nut neither has a ball bearing nor actively rolls.
Ball Screw Pros
Ball screws offer a high level of mechanical efficiency. As per statistics, ball screws are almost 90% efficient. In other words, they successfully convert nine-tenths of the application’s rotational motion into linear motion. In comparison, Lead screws have a very low level of mechanical efficiency of just 20% to 25%.
Therefore, ball screws are three to four times more efficient in converting mechanical energy than lead screws. Moreover, ball screws produce less friction because they are designed with a nut fitted with ball bearings. Ball bearings provide a smooth surface for the screw that reduces friction and subsequently increases the ball screw’s lifespan.
Ball Screw Cons.
The only problem in using ball screw nuts is their susceptibility to being back-driven. Since they create virtually no friction, they can be back-driven at certain lead angles. Besides, ball screws cost marginally more than other mechanical devices, including lead screws. The higher cost of manufacturing may deter them from choosing ball screws. But superior mechanical efficiency and low internal friction are taken into account. In that case, ball screws will always be preferred by manufacturers who are more concerned with the quality and performance of their products.