Product category:
Bearings
News Release from: Igus UK | Subject: Linear sliding bearings
Edited by the Engineeringtalk Editorial
Team on 07 August 2001
The benefits of Linear Sliding Bearings
explained
What is the difference between a conventional linear ball bushing and a modern linear sliding bearing? The answer is that modern linear sliding bearings are known for their capacity to run totally dry
What is the difference between a conventional linear ball bushing and a modern linear sliding bearing? While traditional rolling bearing technology cannot operate without oil or grease, modern linear sliding bearings are known for their capacity to run totally dry For many industries and applications this provides a number of advantages which can be used to arrive at innovative and low cost solutions
This article was originally published on Engineeringtalk on 21 Jul 2008 at 8.00am (UK)
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For example, dirt particles are not attracted to the bearing surface, and machine operators do not come into contact with grease.
Polymers guarantee modern light weight design, freedom from corrosion and extremely high strength.
For many years igus has been involved in the development, manufacture and processing of self lubricating high performance polymers.
Using injection moulding, these high performance plastics are processed into rotational bearings, spherical bearings and linear bearings.
For each individual type of motion the most suitable compound must be found, the result is that thousands of tests are carried out and evaluated each year at igus.
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This database of various polymer-shaft combinations, the biggest in the world, is the basis for the constant optimisation of the materials which all have a similar structure.
Solid lubricants, reinforcing fibre materials as well as additional filling materials are added to a specific base polymer in precise proportions.
The resulting materials guarantee the lowest possible friction value and best wear characteristics when running dry as well as allowing surface pressures up to 150 MPa.
DryLin linear bearings are unique in that the polymer bearing is a liner or sliding strip which is fitted into an alumnium housing which guarantees a stable and reliable connection.
If it is ever necessary to replace this liner the procedure is extremely simple and can be performed quickly by hand.
The universal application of linear sliding bearings is only limited when the requirement is for total precision and/or extremely low friction, for example in the bed of a machine tool.
The standard DryLin linear bearing range uses the iglidur J material as standard.
As well as having excellent material properties, a patented bearing geometry guarantees the suitability of the polymer material as a robust, dirt resistant linear bearing.
The individual sliding elements are joined together by thin films which creates an area which allow dirt and dust to pass through.
No accumulation of material occurs at the leading edge of the bearing, and the sliding elements can pass through any environment simply and quickly, like a snow plough, over the shaft.
As the bearing is designed for use without any lubrication, particles of dirt are prevented from bonding and hardening on the shaft.
In addition, no expensive sealing solutions are required.
The construction of DryLin linear bearings - no moving parts - theoretically means that unlimited acceleration and velocity values can be expected.
In practice the velocity is limited by the masses to be moved and the resultant PxV values.
Speeds of more than 10 m/s can be achieved with DryLin linear bearings.
The negligible moisture absorption of iglidur polymers is complemented by the use of anodised alumnium as a housing and shaft material.
These materials are known for their 100% corrosion resistance, even in continuous underwater use.
DryLin linear bearings can be used in applications which run continuously submerged as well as in situations where frequent washdowns occur.
As the bearings do not require lubrication, no regreasing is required after a cleaning operation.
The complete range of DryLin shaft and bearing systems can be varied easily and inexpensively into a temperature and chemical resistant product using sliding elements made from iglidur X.
This material can resist temperatures up to 250C, and the dry running feature means that no additional sealing or high temperature greases are required.
The iglidur X option does not have an adverse effect on the excellent friction and wear properties of DryLin.
Numerous test results by the R and D department show that iglidur X becomes even more resistant to wear with increasing temperature.
The friction values of iglidur X are also the very best, with stainless steel a coefficient of friction of 0.16 can be achieved.
Iglidur X has almost universal chemical resistance, the only proven problem areas are concentrated nitric acid and sulphuric acid with a concentration of more than 65%.
The maximum moisture absorption of iglidur X is less than 0.5% by weight, and opens up applications in the food and packaging industries.
Polymer sliding elements that run on polished shafts or alumnium profile rails hardly give any noise or vibration.
The metallic rolling noise which is inherent in a ball bearing linear system is totally eliminated.
The noise development is also completely independent of the motion, even with short and extremely fast strokes the noise is only a fraction of other linear systems.
Recently igus has been offering an additional online service to design engineers.
The DryLin linear technology range is available in 3D CAD format for most CAD systems at www.igus-uk.co.uk.
The futuristic vision of the designer who calculates the service life of a linear bearing online for their application is about to be implemented.
Already, igus technical staff are using computer assisted expert systems to give definite statements on the suitability and service life of DryLin linear bearings.
These statements are not theoretical assumptions, but are based on data obtained from thousands of documented standard tests.
Over 2500 tests are carried out each year in the igus test laboratory, most with running times of over 100 hours. Request a free brochure from Igus UK ...
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