Personal robot with maintenance-free rear axis

Profile
What was needed:
Durable and maintenance-free components for the rear axle of a personal robot

Requirements:
Self-lubricating and maintenance-free plain bearings that are weather-resistant and suitable for high loads

Sector:
Automation

Success for the customer:
By using the PRT slewing ring bearing, the rear axle of the robot is lubrication- and maintenance-free. In addition, the service life of the PRT was calculated in advance for use in the robot and far exceeds the design requirements.

The smartest of its kind

"Willow is the most intelligent garden robot currently on the market. Other robots need a perimeter wire so that they only stay in the desired area. Our robot doesn't need one at all and avoids obstacles in the garden with ease," explains Gary Gilmartin, Mechanical Design Engineer at EEVE. This perimeter wire is normally laid on the ground, the robot registers it and therefore only stays in the defined area. Thanks to computer vision and artificial intelligence, Willow can navigate autonomously and thus offers scope for many other applications. For example, the robot tends the garden, guards the property, sweeps the patio with an extension, transports goods or plays clearance. It can be taught new tasks without any programming effort. This makes Willow easy to operate and expand and can be realised by anyone.

There is no such thing as bad weather, there are just wrong components

A robot that works in rain or sunshine, in cold or heat, places a high load on its components. Willow also has to withstand salty air when it is used in coastal areas. Because of these environmental conditions, EEVE decided in favour of using igus® components. They are known for their durability, even under adverse operating conditions. The cooperation was triggered by a sample set of iglidur® bearings that caught Gilmartin's attention some time ago. "I knew I would need them in the future," he says.

Originally, the company EEVE installed iglidur® thrust washers in its robots on the rear axle in order to reduce friction when the rear wheel rotates. When upgrading a customer robot, an iglidur® PRT slewing ring bearing was used on the axis for the first time. Now an iglidur® PRT-02-20 is used in the rear axle of the robot. In order to optimally meet the requirements of EEVE, igus® designed a customised solution with reduced required drive torque. It ensures that the rear wheel can rotate freely even under harsh operating conditions and without any maintenance effort. "Our customers need a product that can stand outdoors maintenance-free for many years. Our aim is to ensure that our robots always work without having to be taken to a repair service at any time," says Gary Gilmartin, explaining the use of PRT slewing ring bearings.

Service life calculated in advance

igus® calculated the service life of the slewing ring bearing for EEVE in advance with the help of a free online tool: the so-called iglidur ® PRT expert. All the data collected in the igus® test laboratory on the service life of the slewing ring bearing is fed into this tool, enabling an accurate prediction of the product service life. "In our case, the service life far exceeds our design requirements," notes Gilmartin. "The PRT slewing ring bearing is the only bearing we wanted to use. Compared to ball bearing slewing rings, it offers a clear price advantage," he adds. In addition, ball bearings have to be replaced much earlier and lubricated regularly due to the dirt and dust load. "Even in harsh environmental conditions, our slewing ring bearings enable robust and maintenance-free operation for at least ten years. In the EEVE application, the service life is 90 years," explains Joren Kestens, who works in field service at igus®.

Click here for the products used
iglidur® PRT slewing ring bearing