Roller bearings
Wire roller bearings for small installation spaces – lightweight, compact, and resilient
Franke wire roller bearings combine low weight, compact design, high rigidity, and defined rotational resistance—ideal for uniform movements in automation and robotics.
The key difference between a standard ball bearing and a Franke wire roller bearing lies in the raceways. In wire roller bearings, the rolling elements do not roll on solid housing rings, but on hardened wires. The flexibility of this principle allows for freer and simpler designs, resulting in better products. Thanks to their patented technology, Franke wire rolling bearings offer maximum design freedom without compromising on load capacity.
Franke LER bearing elements are suitable for medium rotational speeds and accuracies. They impress with their smooth running, high dynamics, and compact installation space. The straight contact surfaces allow for easy integration into the surrounding design and high rigidity. The favorable price makes the LER bearing element an economical solution. LER bearings are usually installed without play. The preload can be individually adjusted depending on requirements.
The new LER1.5 series was specifically developed for use in ultra-compact applications such as MRK robots or medical devices. With an installation space of just 5x6 mm, the new LER 1.5 also meets the trend toward miniaturization in the handling and automation sector. Small rotary tables, grippers, or manipulators can be moved precisely and with high load capacity.
Application example: LER 1.5 in sensitive robots
A new generation of robots is on the rise: lightweight, quiet, extremely agile, and highly sensitive to their surroundings. They are finding their way into everyday life and industry, where they are becoming partners to humans. In addition to households and manufacturing facilities, these smart robots are increasingly conquering the healthcare, logistics, and entertainment sectors.
The market for compact, intelligent robots is growing rapidly, driven by advances in sensor technology, AI, and drive technology. Double-digit growth is expected for collaborative robots (cobots) by 2030. In Asia, Europe, and North America, the automotive, electronics, and medical industries are particularly keen to embrace this technology.
One key to success: innovative technologies such as wire roller bearings, which enable precise, reliable, and energy-efficient movements. Their compact design and high performance meet the central requirements of modern robotics – from surgery to warehousing.
Mechanical properties such as slim design, low weight, and high mobility are essential for flexible applications. Robot joints therefore require bearings that weigh little, take up little space, but are rigid enough to safely absorb torques.
Also required: defined rotational resistance for precise drive design. Franke wire roller bearings with rectangular profiles meet all these requirements. They consist of hardened raceways with profiled running surfaces and are integrated directly into the design. This saves space and offers freedom in design. Their low weight also allows the use of alternative materials such as aluminum, plastic, or carbon.
The arrangement of the raceways allows the bearing to be adapted to the prevailing load conditions. Further adjustments can be made via the degree of contact, i.e. the size of the contact area between the rolling elements and the raceway. The large number of joints, especially in the latest robot designs, also bring economic aspects into play when selecting the right bearing. Parameters such as ease of installation, installation time, and, of course, price play a role here. Franke wire roller bearings also impress in these areas. Installation is simple, and the prices for bearing elements or thin-section bearings in series production are extremely attractive.
Direct drive with torque motors
In their highest configuration, Franke wire rolling bearings are available complete with drive. Torque motors integrated into the housing act directly on site—without additional drive or transmission components and with maximum efficiency. Wire rolling bearings with integrated drives have been used in computer tomographs for decades. There, they reliably and uniformly accelerate X-ray units weighing up to one ton to speeds of up to 400 rpm, enabling high-resolution images of the human body to be taken.
Direct drives can be combined with all types of wire roller bearings. A LER1.5 with an adapted direct drive could be used to create extremely compact robot joints that only need to be controlled and integrated directly into Franke rotary unions. The customer receives a ready-to-install system that can be positioned precisely and execute defined cycle steps.
High performance and defined movements
The torque motor has high torque within a defined speed range. The distance between the stator and rotor (air gap) is decisive for the magnitude of the torque. The preloaded Franke rotary joint guarantees a constant air gap. A measuring system can be used to determine the motor position.
The large center clearance of the wire-wound bearings with direct drive can be used to save material or to accommodate additional technology such as measuring systems or control units.
All measuring systems available on the market can be integrated into the rotary joint. Very robust inductive measuring systems are used as standard. They are available as incremental or absolute systems in various accuracy classes.
To the Video (D): Rotary connection with torque motor (direct drive)
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73431 Aalen
GERMANY
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