Tough transducers ensure precise road maintenance while reducing machine downtime

Roadtec manufactures a variety of road building and asphalt paving equipment, relying on hydraulics for the power density and precision control it provides in cutting, paving and more. The company’s soil stabilizers and road reclaimers are well balanced and constructed with a sealed box frame to make them as durable and versatile as possible.

Used for road rehabilitation, cold recycling, or soil stabilization, different models feature hydraulically driven cutters, hydraulically driven suspension for precision cutting depths which is done easily via a push button, hydraulically adjustable doors to allow for easy access to the engine compartment, and hydraulically adjustable front and rear doors combined with optimal drum position in the cutter housing to provide sizing and material flow.

When servicing the magnetostrictive sensor buried inside the main lift of its SX model reclaimer/stabilizer machines became too difficult and time-consuming, Roadtec turned to Rota Engineering for a simpler solution. The company replaced all magnetostrictive transducers mounted on the main lift cylinder with Rota’s internal or external transducers where it was difficult to replace and maintain the transducer.

Rota’s external transducer allows fast on-site maintenance and minimum machine downtime. This is particularly useful when the cylinder is large and well integrated into the machine, said Michael Moore, Technical Sales for Rota.

“Prior to switching to Rota Engineering sensors in 2010, Roadtec had less than satisfactory experience with magnetostrictive sensors buried inside cylinders that turned out to be difficult and time-consuming to service. To service a sensor, they had to fully remove the hydraulic cylinder from the machine using a mobile crane or skid steer loader. Servicing the sensor in the field turned out to be unfeasible in practice as the hydraulic cylinder had to be returned to a cylinder repair facility,” Moore said. “Minimizing downtime was and still is a priority in terms of Roadtec competing for market share. Another aspect to minimizing downtime is sensor reliability. With Rota designs, Roadtec has met their service level expectations.”

Roadtec first installed Rota sensors on its SX models of its reclaimer/stabilizer, where hydraulic cylinders with linear sensors are used on elevation, cutter door height and gate, and steering. Rota sensors were later retrofitted on its cold planers and material transfer vehicles (shuttle buggies).

The elevation cylinder supports the mass of the entire machine on its cylinder pins. As such, unpinning one end of the cylinder to gain access to the sensor was not practical as either a mobile crane or skid-steer loader would have to be used to relieve the force on the pin in order to remove it. For the elevation cylinders, Roadtec elected to go with the Rota external linear (EL) series sensor. The Rota EL sensor allows the user to replace the sensor element without touching the hydraulic cylinder at all. Protection of the sensor is afforded by the elevation support box beam, which surrounds the elevation cylinder and sensor.

Rota’s EL sensor is suitable for steering and long cylinder applications. It uses Rota’s non-contact, Hall-effect technology, which does not require gun drilling and allows for easy on-site replacement. In this design, an internal magnet communicates with the externally mounted sensor.

In other instances, Roadtec opted to use Rota’s LA series internally integrated sensors wherever possible as the cylinder tube provides best physical impact protection for the sensor. However, serviceability of sensors was also a priority, as downtime must be kept to a minimum.

“The Rota LA series sensor provided the best solution accommodating both protection and serviceability requirements. Where the LA sensor is used on the machine, the hydraulic cylinder can be unpinned on one end to gain access to the sensor for service and/or replacement, which is easily supported in the field,” Moore said. “Rota’s Hall Effect sensor has flexibility in mounting design to accommodate this requirement. The other primary benefit to Roadtec was superior reliability of the Rota Hall Effect sensor compared to Roadtec’s prior sensor designs. Shock and vibration are virtually constant when the machines are in operation. Rota has field proven reliability in high shock, high vibration applications.”