Edited by Mike Santora
Whether it’s agricultural machinery, construction equipment or municipal vehicles, intelligent sensors are indispensable nowadays throughout the mobile machine market. Recording paths and angles is an integral component of intelligent operating functions. These functions improve not only the convenience, but also the safety of mobile machines. Using intelligent sensors also increases the performance and efficiency of mobile machines, allowing repetitive work processes to be automated.
Measure and monitor motion sequences
The SGH wire-actuated encoder measures the absolute, direct cylinder stroke in the hydraulic cylinder. The SGH10 is pressure resistant up to 300 bar with pressure peaks up to 500 bar and also has an operating voltage from 9 to 36 Vdc.
As most motion sequences for mobile machines use hydraulic cylinders, one of the most important measurement tasks for sensor technology is determining the stroke of the cylinder to enable measurement and monitoring of the motions. No wonder then, that both machine and sensor manufacturers are always looking for new innovations in stroke measurement for hydraulic cylinders. This need prompted SIKO to develop the SGH10 measurement system for direct stroke measurement in hydraulic cylinders. The cylinder stroke is measured using Bowden cable sensor technology installed directly in the cylinder, and the plug ensures the system is fully IP69 protected.
The SGH10 cylinder stroke measuring system pursues an entirely different technological approach than some other measuring systems based on magneto-restrictive, inductive or Hall-based technology. In contrast to these systems, a Bowden cable mechanism installed directly in the cylinder is used to measure the stroke. The cable of the Bowden cable mechanism is mounted in the piston head. If the cylinder is extended, the cable, which is wound up in a cable drum, is pulled out. The rotation of the cable drum is then detected without contact by the sensor electronics and used to calculate the linear travel. This process makes it possible to detect the position of the cylinder precisely at all times.
The magnets that are used to detect the rotation are scanned by the electronics through the pressure-resistant base plate of the SGH10. The electronics are fully encapsulated on the unpressurized side of the system. This means the entire measuring system is built into the cylinder and is protected from environmental conditions. This provides a clear advantage: In contrast to a measuring system mounted externally on the cylinder, the sensor system cannot be damaged by loose parts.
Piston drilling unnecessary
Another aspect is the reduction of costs for integrating the system into the cylinder. This is because in previous measuring systems, the sensor rods had to be integrated into the piston over the entire measuring path; this often required long and highly precise bore holes in the piston. This is not only expensive, but also weakens the structure of the piston. In the SGH10 stroke measuring system, just one small thread is needed in the piston to mount the cable. This allows the system to offer overall cost savings for hydraulic cylinders.
SGH measuring technology can also be used in telescopic cylinders. The technology provides design engineers with options when developing assistance systems and supplemental functions in mobile machines.
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Filed Under: Cylinders & Actuators, Sensors
