There is a vast range of linear motion products on the market and it can be difficult to know which product to select. This article discusses the various types of products available according to their rolling element and explores their advantages, disadvantages and limitations. Finally a selection chart clearly lists each product’s characteristics to help with specifying the best linear motion product.
Some of our linear motion products are shown in the table below:
What are Linear Motion Products?
The primary purpose of linear motion products is to move something from one place to another in one direction along a straight line. Usually this is achieved using a bearing with a rolling element. Traditionally this rolling element would be a ball or roller, but these days some linear motion bearings do not incorporate a rolling element and consequently are known as ‘plain’ bearings. These plain bearings are simply plastic or ceramic bushes and are sometimes lined with PTFE or oil impregnated plastic to help reduce the sliding friction. Continue reading
When the Landscape Director from N T Killingley contacted us about sliding a planter in and out of a glasshouse at RHS Chatsworth, our Technical Sales team listened to his specification and suggested various options. Their requirement was a system that was simple to install and robust enough to carry the weight of a laden planter, but most importantly would not cost a fortune as the display was temporary.
The combined roller bearing system met this criteria. By using the rails upturned, there was very little set up involved and the bearings and mounting plates were simply bolted to the underside of the planter.
The end result was a system that was discreet and could be operated with very little effort. The display formed part of the “Garden for a Changing Climate” at RHS Chatsworth in June 2017 and featured on BBC’s Gardeners World.
The RHS video of the garden can be viewed here. And the BBC Gardeners World episode can be viewed here (approximately 41 minutes in).
If you need help to specify a linear sliding system, please contact us. We have a team of Engineers & Designers who can guide you through both selecting the most suitable product and specifying the correct size.
Photo courtesy of N T Killingley © 2017
Our Euro-Vee Bearings are available in 4 sizes which can take radial loads from 100kg up to 800kg. A cost effective linear sliding system can be built using our corresponding T Rail and Euro-Vee Bushings for applications requiring either vertical or horizontal movement.
The bearings are sealed and lubricated for life and so will tolerate being used in dirty environments. The Vee Bushings are used to mount these bearings. We have both concentric and eccentric bushings on stock, in both imperial and metric sizes.
A typical system would use a pair of rails with a minimum of four bearings acting as wheels for a carriage. Half the number of bearings would be mounted on the concentric bushings and the other half mounted on the eccentric type. All the bearings are held in position on their bushings by a bolt fixed through the centre of the bushing. By rotating the eccentric bushings it is possible to tighten the bearings onto (or off) the track. The eccentric bushings have a hex head so that they can be rotated with a spanner before their fixing bolts are tightened back up. The system should be designed so that the main loads are taken by the bearings on the concentric bushings.
The T Rail can either be drilled and bolted down (to a square edge) or it can be welded into position. The body of the rail is soft so it can be easily drilled. The top edge of the rail (where the bearing runs) is induction hardened and polished.
It is also worthing knowing that our Euro-Vee Bearings can be run on round (hardened and ground) linear shaft.
Example applications include:
- packaging machinery
- laboratory automation
- woodworking machinery
- vending machines
- sliding doors (eg machine tool doors)
Our Euro-Vee Bearings are also available in stainless steel.
Our Combined Roller Bearings consist of a radial bearing, an axial (face) bearing and a weldable hub. The main radial bearing can take very high loads and the axial roller takes side loads and prevents the bearing from crabbing in the channel. Used in conjunction with their mating steel channel it is possible to design and build a heavy duty linear sliding system, for either horizontal or vertical motion. More complicated systems can be built using the bearings and channel to create telescopic and cantilevered solutions. We can help you to select the correct size for your application. Our bearings range in size from an outer diameter of 52.5mm all the way up to 390mm (Jumbo CR range).
The hub of the bearing is weldable so that the bearing can either be welded directly to a structure or to a mounting plate. We keep the standard mounting plates on stock and we can supply the bearing welded to its plate. The standard mounting plates have both threaded holes and thru holes so that the plate can be fixed from the front or the back. We can fabricate bespoke mounting plates to your design.
We also offer a range of combined roller bearings that a have an eccentric adjustable face roller. The height of the face roller can be varied by removing the front face plate and rotating the shaft of the axial bearing, the ends of which are splined. More information on our website here: Eccentric Adjustable CR Bearings
If your application does not require the axial (face) roller then you could use our Radial Bearings which offer all the advantages of our Combined Roller Bearings and are designed to run in the same steel channels.