Innovative, extremely powerful technology
Thanks to their special technology, cycloidal gears offer a high degree of precision, dynamics, torsional rigidity and compactness. They are extremely resilient, resistant and low-wear and position with high precision over their entire service life. The integrated angular contact ball bearings absorb axial and radial loads as well as bending moments and contribute to the high tilting rigidity and resistance to impact and overload. The virtually backlash-free precision gearboxes are particularly lightweight, space-saving and yet powerful - ideal for all applications that require maximum performance in a compact design.
Functional principle
The two-stage reduction principle (spur gear stage and eccentric stage) reduces vibrations and mass inertia. The almost complete contact and even force distribution within the gearbox also allow a high load with low backlash. In emergency stop situations, the gearbox can absorb up to 500 % of the rated torque. The rolling friction of all elements involved in the power transmission also guarantees a very low breakaway torque. This means that very high torques can be transmitted with maximum precision (hysteresis loss < 1 arcmin, pure backlash 0.1-0.2 arcmin) and smooth running, and high reduction ratios (30:1 to over 300:1) can be achieved thanks to the two reduction stages.
Structure
Cycloidal gears essentially consist of four components: a drive shaft, two or three eccentric shafts, two cam disks and an output shaft that runs slowly according to the reduction ratio . Power is transmitted via the cam disks, the bearing-mounted eccentric shafts and the rollers installed inside the housing. The rollers force the output shaft to rotate.
Functionality
In the first stage, the rotary motion of the drive or servomotor is transmitted to the spur gears via the input shaft. The speed is reduced according to the reduction ratio of the input shaft to the spur gears. The spur gears are mounted on three eccentric shafts, each of which has two eccentrics for the two cams. The cams are offset by 180° in relation to each other and are driven by the eccentric shafts. Needle bearings ensure that the movement is transmitted as smoothly as possible. The cams rotate within the housing lined with rollers (second reduction stage). The cam disk has exactly one cam section less than the ring rollers and almost half of the cams of each disk are in constant contact with the rollers. With the two 180° offset discs, this results in almost a full circle of contact.
Your advantages at a glance
- Extreme precision
- High shock load capacity
- High torque performance
- High rigidity
- Low mass moment of inertia
- Insensitive to vibrations
- Low wear and particularly durable
- Minimal space requirement
"RV" stands for the "Rotor Vector" design of our gearboxes and thus for their extremely high load capacity and precision.
State-of-the-art storage concept
Our cycloidal gears have a strong integrated main bearing with large angular contact ball bearings and a large number of rolling elements. As a result, they can absorb around 250 % higher bending moments than conventional planetary gearboxes of a comparable size. Thanks to the solid bearings, the cycloidal gears also take on a load-bearing function in the robot, machine or system, making additional external bearings superfluous. This enables more compact designs, reduces the design and assembly effort and lowers costs. All bearings are assembled and preloaded by Nabtesco itself.
Integrated main bearing:
- Absorption of high bending moments
- Load-bearing machine element
- No additional external bearing required
- Handling of heavy loads
- Construction of more compact robots, machines and systems
- Reduced construction and assembly costs
A real alternative to low-backlash planetary gearboxes
If precision and positioning accuracy are of essential importance, cycloidal gears consistently offer better performance data compared to planetary gears.
- More robust construction
- Longer service life
- Virtually no increase in play
- Higher rigidity
- More compact design
- Lower weight
- Higher overload safety
- No additional pre-stages
At the end of the 1920s, the German designer and entrepreneur Lorenz Braren developed a completely new type of technology: the cycloidal gearbox. It used bolts and rollers to transmit power instead of the usual gear wheels - the cycloidal gear was born. The invention was originally intended for use in cameras, but thanks to their outstanding features, the gearboxes are now mainly used in robotics and other high-tech industries.
The first cycloidal gearbox from Nabtesco dates back to 1980, when it was used in travel drives for excavators and was not yet a precision gearbox. With the emergence and triumph of robot technology, Nabtesco solutions then found their way into industrial robots - and the great career of precision gears began.
The first precision gearbox from Nabtesco in cycloidal design was the RV gearbox. It came onto the market in 1985. Even then, the gearboxes featured the typical two-stage reduction principle and three eccentric shafts. The standardization also set standards: The cycloidal stage within a size is uniform, the different ratios are provided by the spur gear stage.
We are the world's largest manufacturer of cycloidal precision gearboxes and offer you the most comprehensive and deepest product portfolio on the market. Our powerful cycloidal gears guarantee efficient, reliable processes and ensure significant performance improvements and cost savings in your application!
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