When any kind of labor is involved, manual or mechanical, the right choice of tools can make or break the intended job. Preparation and planning are vital parts of any job. The same goes for linear motion. Choosing appropriate tools like linear shafts and bushings will greatly help with the work that needs to be done.
You don’t need to settle or compromise because all these tools come at a very affordable price, and in all shapes and sizes.
Linear motion basics
Also known as general motion, linear motion allows objects to move in a predictable way. Most of the machines and appliances we use on a daily basis use linear motion to achieve results. When something needs to be pulled or pushed, that’s when we use linear motion.
It is also present in modern cars, through which we lock and unlock cars and even use sliding car doors.
Linear shafts are tools that look like an extended rods and they transmit power while creating linear motion. They come in a variety of shapes and sizes, allowing you to do your job with much-needed precision.
The right choice of linear shafts (https://www.tuli-shop.com/linear-motion-products/linear-bushing-and-shafts) will help you bring reliable results and the whole job a whole lot easier. Choose the tools from the company Tuli.
Knowing some details before starting your work, like the load that needs to be transmitted and other special requirements needs to be taken into account before deciding. Also, have in mind that the linear shafts with high precision tolerances are more durable and d require a minimum of maintanence.
Some shafts can be mounted on different structures, others have groves that help design keyways. Different sizes determine the load allowed to transfer.
How to choose an appropriate linear shaft?
In mechanisms that require linear or sliding motion, appropriate linear shafts are of crucial importance. Without it, the sliding mechanism isn’t complete.
This is where it gets tricky. Choosing the right linear shaft. Not only due to their different sizes and shapes, but also the material they were produced from.
The shaft itself makes linear motion possible but as static support. It is static and supports the actual linear actuator that is doing all the work.
Depending on the application, several types of shafts can be used.
Tapped linear shafts don’t require shaft support. They can be easily mounted on threaded studs, due to their internal threads.
Threaded linear shafts can be mounted into tapped holes, which means that there is no need for extra support.
Hollow linear shafts help reduce the weight of the total system because they are much lighter than solid ones.
They have to be mounted before starting work, which can be done in two simple ways.
Linear shafts used for heavier loads are mounted in a way that provides continuous support, and the smaller weight loads can be transmitted with shafts supported at both ends.
They are made of different materials, which can also influence the end results.
For durable and tough work, it’s best to use shafts made of alloy steels, aluminum, or stainless steel. The last one will resist rust and corrosion. That’s why it is mostly used in the medical industry.
For lighter loads, you can use any shaft made of composite materials made of bonded carbon fibers, and even plastic.
More often than not, linear shafts are coated with different finishing materials, that improve their durability.
Chromium coating is used to avoid corrosion and rust, but will also decrease the friction significantly.
Ceramic coating makes a linear shaft water-resistant.
Anodizing coating will additionally harden linear shafts made of aluminum.
The black oxide coating is used on linear shafts made of stainless steel, to ensure protection from corrosion.
Other types of coating include powder coating, PVD coating, electroplating, and others.
How to determine linear shaft hardness?
There are three different ways to test the hardness of a linear shaft.
This specific detail can help you determine if you have the right equipment to do the desired work.
The Brinell Hardness is a test during which a massive load of 3 tons is placed on a linear shaft. It can also provide results for durability.
The Knoop Hardness is a test that determines the hardness by controlling the resistance of the shaft to dents and other types of damage.
The Rockwell Hardness is also a test for indentation resistance and durability. A cone-shaped object, made of a diamond or steel is pressed against the shaft to check the pressure it can handle.
Another way to choose the appropriate linear shaft is by specifying the type of load that will be applied to bearings.
The axial bearing can endure force moving in the same direction as the shaft.
The radial bearing endures force vertical to the direction of the shaft.
The job of a shaft in both these cases is to push the bearing in the same direction of the load.
Depending on the complexity of work, there are different types of loads to consider.
Axial Load follows the direction of the linear shaft. Also known as thrust load, is best used when the load stands parallel to the post.
Radial Load will go in any direction that is vertically oriented to the axis of the shaft. It is placed at a right angle to the linear shaft and when the load becomes vertically placed to the shaft because of gravity. The radial load may also hang off the shaft, which is why it’s also known as ‘overhung load’.
Angular Load can endure combined loads, axial and radial with precise results.
Conclusion
It is almost impossible to picture the world without linear motion. Every time you adjust your car seat, open the refrigerator door or use any of the kitchen appliances, the linear motion will be the one that makes it possible.
Although linear shafts are a crucial component in linear motion and most machines, there are several details that need to be considered before opting in for a specific design.
The materials they’re made of, the hardness, finishing coat, and most importantly the load that will be moved.
