Robust, wear-optimised guide systems in EME Parker linear actuators

• What was needed: Linear bearing systems from igus®
• Requirements: Linear actuators in conventional systems often have problems such as carrying dead mass with the slider, an unfavourable lever ratio between support and load arm, they require lubrication and cleaning as well as regular maintenance
• Industry: Manufacture of machine parts
• Success for the customer: guide systems from igus® are the optimum alternative for Parker EME: among other things, they are extremely robust, have optimum wear and friction properties and do not require lubrication.

Linear actuators with a conventional guide system can cause a variety of problems in a design, for example they often involve a large moving dead mass in the slider. In addition, there is an unfavourable leverage ratio between the support arm and load arm with internal guidance, as these are located far away from the load. The speed is limited (especially with recirculating roller guides) and acceleration is restricted. Track roller guides in particular give way quickly under high moment loads - as track roller axes can be bent or misaligned, they are very susceptible. Not forgetting the lubrication usually required for these machine elements, which attracts dirt and where grease or oil discharged can contaminate the entire system. They must be installed in a protected location or fitted with bellows as a cover. The regular maintenance required - usually cleaning and relubrication - makes them even more expensive. Last but not least, the multi-part overall system means high assembly costs. Christoph Lindemann, Product Manager for Mechanical Components and Systems at Parker EME in Offenburg, also knows the risks and side effects in practice: "Our existing linear actuators are predominantly equipped with roller guides. For clearance-free adjustment, the skate wheels are attached to the slider with screws and eccentric bushes - a so-called "cantilevered attachment" is created. If the skate wheels are already working close to their maximum load-bearing capacity during normal operation, a collision, for example, can easily lead to these fastenings becoming misaligned or even bent. Even short-term overloaded guidance can therefore cause serious permanent damage to the entire system. The ratio of harmful to typical load is in the range of 3:1 and 5:1."

This is not the case with the guide system drylin® WQ from igus®, which Parker EME installs in its linear actuator "LCB". Here, this ratio is between around 100:1 and 500:1. These figures show the extreme robustness of the guidance. After all, the slider transmits the forces directly to the guideways. There is no possibility of adjustment and the risk of bending is practically eliminated. 
The sliding elements are made of high-performance polymers. For most applications, the use of iglidiur J material is recommended due to its wear and friction properties. The drylin® linear bearing systems are generally designed for dry operation. Contamination from grease or oil is therefore a thing of the past. Ambient dust or abrasion during machining are not bound to the bearing point. drylin®-guidance is divided into two main groups with different geometries: profiled rail guides and shaft guides.
In the drylin® T system, the slides run on a T-rail made of hard anodised aluminium. All connection dimensions are identical to most commercially available recirculating ball bearing systems. A miniature version can also be accommodated in the smallest installation spaces. Extremely flat "N" variants are available in four sizes from 17 to 80 mm rail width. The carriages move in C-profiles made of anodised aluminium.
drylin® R linear plain bearings, on the other hand, which correspond to the size of ball bushings, use round shafts as mating partners. Different shaft materials are used. For example, hard-coated aluminium shafts guarantee low wear and a low coefficient of friction. The drylin® W linear guides used by Parker EME combine two round shafts, rectangular guides and the carrier profile for the linear actuator in one profile made of hard-anodised aluminium. They allow maximum design freedom thanks to different shaft diameters, profile widths, slide lengths and geometries.