NORGLIDE^® Plain Bearings for Robotics and Automation

Industrial robots and cobots are now firmly established in production. Their tasks are becoming more and more diverse and the interaction with humans is presenting developers and manufacturers of components, such as robotic bearings, with ever greater challenges.

Nevertheless, the more robots are used in manufacturing and service, the greater the risk of an unexpected production line stoppage. Robotics market experts estimate that a 0.25% annual efficiency increase for a production line with an hourly machine cost rate of €2,500 results in an annual savings of €25,000.

Certainly machine maintenance is key and every company sets maintenance standards for automated lines. Better and more cost-effective solutions and designs for critical components help to avoid unattractive maintenance efforts and costs. And it's the moving parts, like robot joints, that have a big impact here.

Robotic Bearings 

Rotational or swiveling movements of a robot require joints in which robotic bearings ensure "smooth" operation. Robot bearings manage the balancing act between zero clearance, high load capacity, low friction and small installation space. In most cases, rolling bearings such as ball bearings, crossed roller bearings or angular contact roller bearings are used here. Especially in small spaces, rolling bearings quickly reach their limits, resulting in lower load capacity and higher coefficients of friction.

An alternative to this are plain bearings. Some types of plain bearings offer high load capacity and low friction even in small installation spaces. A detailed overview of the various bearing concepts can be found in our article Bushings vs Bearings: What is the Difference?. 

Maintenance-free sliding bearings

Maintenance-free sliding bearings, such as NORGLIDE^®, are a good alternative to rolling element bearings. Especially for oscillating movements, under high loads and low speed, there is no risk of brinelling effect when using NORGLIDE^® Bearings. The composite plain bearing is self-lubricating and requires no additional lubricants. The low coefficient of friction of PTFE and its low stick-slip effect make rotary movements of robot joints smooth.

NORGLIDE^® from Saint-Gobain is a high-performance material and our experts will design a plain bearing to meet your requirements. The Advantages of NORGLIDE^® at a glance:

• Low wear and constant friction 
• Maintenance-free and self-lubricating
• Low torque 
• High load capacity 
• Resistance to chemicals
• High corrosion protection
• Tolerance compensation 
• Compensation of misalignment
• Space & weight reduction of the whole system 
• Noise & vibration reduction
• Allowance for electrically conductive bearings

 

NORGLIDE^® Robotic Bearings

NORGLIDE^® Bearings have a modular design and there are numerous variants. A common feature of all variants is a "thick" PTFE-Bearing Compound sliding layer which, in addition to the low coefficient of friction, also ensures low torque due to its elasticity, even at clearance-free bearing points. Due to the appropriate selection of various fillers and the self-lubricating properties, wear particles can be reduced to a minimum, which is particularly necessary in clean rooms as well as in the food processing industry. The metal-reinforced backing of NORGLIDE^® can be made of a wide variety of metals depending on the corrosion requirements. This is a great advantage especially when other chemicals may come into contact with the joints.

Advantages in Design & Manufacturing

 

Clearly, the above properties are important, but they are not outstanding compared to other plain bearing or rolling bearing technologies. The NORGLIDE^® plain bearing offers its greatest advantages through its unique structure. By adding a metal intermediate layer, the load carrying capacity can be further increased. The intermediate layer can, through a calibration process, be plastically deformed and thus backlash-free bearing points can be created cost-efficiently. By calibrating the bearing in the original housing, the overall tolerance range (tolerance of the housing bore + tolerance of the material) can be significantly reduced.

 

 

 

When designing a clearance-free bearing position, the combination of shaft/NORGLIDE^® plain bearing/housing bore is always selected so that a transition fit is achieved. An interference fit is possible because the exceptional PTFE layer of NORGLIDE^® materials provides the required elasticity. After installation, this elasticity ensures that counter pressure is exerted on the shaft. This creates torque in swiveling movements and calibration in combination with precise shaft diameters creates a limited torque range. 

The elasticity of the PTFE sliding layer also reduces the torque caused by possible misalignment. These visco-elastic properties of the PTFE film give the bearings their vibration damping effect.