From Big Data to Smart Data: Gear Units Go Digital

by Christine Rüth
Aug 10, 2016 9:05 AM ET
Siemens is measuring gear unit operating data in order to precisely scale the units for future applications. This is expected to reduce investment costs and help to optimize plant operations.

Pictures of the Future: Digitalization & Software

Siemens has developed a digital measurement technology that records stress in gear units during their operation. The data can then be used to optimize the design of a new gear unit for the same application. This enables overspecification to be avoided without running any risk of undersized units failing due to overloading. Procurement costs are thus reduced, and the data also provide information on how to optimally operate the unit. Flender Gearlog – the name of the measurement technology – incorporates various sensors and a specially developed computer including software for evaluating the data.

Torque Sensors for Large-Scale Production
Siemens manufactures gear units for industrial applications in everything from conveyor belts, cranes, and ships to huge rock mills. The design of a gear unit is determined by the unit’s load spectrum. This is a description of all load states experienced by the unit during operation and the relative durations of these states. In the past, drives ran at relatively constant speeds. The load spectrum resulted from a combination of discrete measurements and engineers’ expertise. Today, frequency converters – which can drive industrial processes at variable rotational speeds – are increasingly being used, so that the rotational speed is adapted to the current operating situation. The systems can now be operated on the basis of a characteristic map and require more comprehensive measurement data. To save energy, conveyor belts, for example, can run faster or slower according to demand. This makes determining the load spectrum much more complicated. In order to rule out expensive downtimes, the greater load is taken as the basis for calculation – resulting in gear units that are often larger than needed.

Many Gear Units in the Same Application
This is where the Flender Gearlog comes in. The measurement technology records speed, torque, vibration, and temperature, with up to 3,300 measurements per second. Siemens specially developed a computer for this high-frequency data acquisition process and the associated software for aggregating the measured values. As a result, only small quantities of data have to be transmitted for further evaluation. Siemens also worked with the sensor manufacturer to develop torque sensors – strictly speaking surface acoustic wave sensors – suitable for large-scale production. The applied load is calculated from the rotational speed and the force working on the components (torque). For excessive loads, the time is also stored in order to be able to subsequently validate the measurement. Siemens is currently the only supplier of this technology for series products.

Gear Units Get a Digital Interface
Companies that use large numbers of gear units – for conveyor belt systems, for example – or many units in the same application, such as in crane fleets, can profit from the measurements generated by Flender Gearlog. As soon as sufficient data has been acquired, the load acting on the gear unit over its service life and how the magnitude of this load changes with time are calculated. Depending on the application, this can be done within months, or in general within one year at the latest. Thanks to extrapolation methods from the automotive industry, the data can enable forecasts covering ten or more operating years.

Flender Gearlog technology is the first to connect gear units with data from the power train and other digital systems. Gear units that have such a system installed receive information on the operating state of their system from Flender Gearlog. The measurements indicate, for example, the proportion of overload or idle states. Unusual load spectra indicate problems in the system. There is also the option, after discussions with users, of collecting and evaluating the operating data from all of the gear units used in a sector or application. This enables patterns to be recognized that can offer valuable pointers to optimizing the gear units or their operation.