A mechatronic solution

The new magneto-elastic torque sensor technology allows the material stresses occurring in a shaft to be directly measured and converted into a torque signal.

Schaeffler thus offers a mechatronic solution that allows applications and processes to be monitored and controlled with  significantly greater precision, as the torque is recorded right where it is applied. In contrast to conventional torque measurement, disruptive influences in the drive train such as torsion rigidity, temperature effects, and losses can be reduced to a minimum. What is more, the contactless sensing means that the measurement takes place with long-term stability. Because the torque measurement is based on changes in the magnetic field and not by evaluating angles of rotation, it is not necessary for the shaft to be weakened. The measuring system therefore causes no loss of rigidity in the drive.


The electronic mass flow control (EMC) metering system from agricultural engineering specialists RAUCH utilizes the proportional relationship between the fertilizer flow rate for each metering slide and the drive torque of the spreader disk (image: RAUCH’s Axis H 50.1 EMC+W fertilizer spreader / image source: RAUCH).


Ready-to-fit mechatronic modules

Schaeffler’s FAG torque measurement module is designed in such a way that the sensors can be adjusted to suit a wide range of different geometries. Shaft diameters of up to approximately 100 mm are currently achievable, with a measuring range covering 100 Nm to 20 kNm. The principle on which these sensors work gives them a high degree of linearity and a very low hysteresis; the achievable degree of accuracy is around 1% of the measuring range. In addition to the torque, the sensor modules also allow the speed to be measured and thus the amount of power transferred to be calculated. This means that the load history of the bearing supports and the drive, i.e. the actual load spectrum, can be calculated. As a supplier of bearing and subsystem solutions, Schaeffler is able to offer this torque sensor technology in a range of ready-to-fit modules. Schaeffler’s application engineers are specialists not only in the field of rolling bearings but also in that of sector-specific mechatronic modules, which means they can develop optimized solutions together with the customer. In allowing machines’ condition and processes to be precisely monitored by recording the torque, Schaeffler is providing an important prerequisite for interconnected and intelligent processes as we progress towards “Industrie 4.0”.



FAG torque measurement modules precisely measure the current fertilizer flow rate, directly adjacent to the process. This makes it possible to always put out exactly the quantity of fertilizer that is required.


Initial applications in agricultural engineering

Torque sensor technology has found its first applications in the agricultural engineering sector. This comes as no surprise, since agricultural engineering is among the most innovative of all sectors: Independently-driven, electronically-coupled vehicles (electronic towbars), sensor technology for measuring the quality of the ground being crossed, digital field record systems and yield charts, interconnection via ISOBUS, and control strategies for the targeted use of seeding machines, fertilizer spreaders, and tillage and harvesting machinery are just some of the examples. Today, agricultural engineering has become fully digitalized. While digitalization has made significant improvements to precision as far as control systems are concerned, the electrical, mechanical, and hydraulic actuators must also be able to implement this precision. This is where the new torque sensors offer a lot of potential.

Torque-controlled fertilizer spreaders

Spreaders of all kinds are designed to spread the material as consistently and evenly as possible. Making more economical use of the fertilizer or manure and adjusting it to suit the terrain increases the yield and improves cost-effectiveness. To ensure the highest possible level of spreading precision, the new fertilizer spreaders from Fliegl Agrartechnik rely on the torque-controlled push-off of material, e.g. digestate, solid manure, and compost. In addition to the excellent lateral and longitudinal distribution, the advantages of this system also include the low level of stress placed on all components, reduced power consumption, and higher output. The FAG torque measurement module transfers its data to the control system via the ISOBUS. All relevant parameters such as the speed and torque of the take-off shaft, the push-off speed, and the system’s hydraulic pressure are recorded using sensors and then processed in the control unit. The quantity of material being spread can be monitored and adjusted from the cabin using the ISOBUS display.

Clear competitive advantages with torque sensors

RAUCH, an agricultural engineering specialist, already has a history of using innovative torque sensor technology in the drive trains of its fertilizer spreaders. The electronic mass flow control (EMC) metering system utilizes the proportional relationship between the fertilizer flow for each metering slide and the drive torque of the spreader disk. Torque measurement as a central control parameter used to be carried out using oil pressure sensors in the hydraulic motors. However, due to the effect of the temperature on the hydraulics and the bevel gears in the EMC spreader’s drive train, the torques generated were subject to variations during the warm-up phase. The latest generation of fertilizer spreaders now features FAG torque measurement modules that are integrated directly into the drive hub. These precisely measure the current fertilizer flow rate, directly adjacent to the process and with no contact. Even blockages and jams in the metering slides are detected. Costly fertilizer spreading thus becomes even more precise and reliable, and unwanted stresses on the environment during the process are prevented.

by Brigida Alessi



To ensure the highest possible level of spreading precision, the new fertilizer spreaders from Fliegl Agrartechnik rely on torque-controlled push-off of solid manure. Fliegl uses the FAG torque measurement module in its ADS push-off fertilizer spreader (image source: Fliegl).



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