Stromag’s clutch delivers long-lasting performance with 20% cost saving
Increasing competition in the agricultural sector means that profit margins are being squeezed. This, in turn, is putting pressure on OEM’s to design new machinery with same performance benefits but at a reduced cost. A major agricultural equipment manufacturer teamed up with Stromag to develop a more cost-effective clutch for its self-propelled forage harvesters. The result is bespoke designed Stromag KHE clutches. These feature fewer moving parts and exceptional long-life performance to meet the application requirements whilst delivering cost savings of 20%.
Self-propelled foragers are among the most powerful farming machines. Used to continuously load crops into trailers, they should feature a robust design that allows them to operate without fault for prolonged periods throughout the long days of the harvesting season. Even more, they should be able to withstand dry and dusty operating conditions, which can take a toll on motors and powertrain components.
A major OEM of agricultural equipment wanted to specify a new, cost-effective clutch to engage and disengage at engine speed the cutting head, or mower, of an innovative forage harvester that the company was developing. The component would be positioned on the vehicle’s power take-off (PTO) shaft, which extends from the gearbox and is installed on a belt drive. PTO clutches play a key role in bringing mower blades to a stop within industry stop times, which are becoming increasingly strict. For example, the American National Standards Institute (ANSI) specifies that commercial riding mower blades must stop within 7 seconds.
The clutches needed to be highly responsive as well as extremely resistant to heat generated by friction and the abrasive dust found in the environment. Furthermore, they were required to minimize the noise produced to protect users and the environment while supporting the identification of unwanted pinging, scraping or rattling sounds that may indicate potential issues in the foragers.
Specifying advanced, cost-competitive PTO clutches
To address these challenges and benefit from a bespoke PTO clutch that could deliver advanced performances at a reduced price, the agricultural equipment manufacturer contacted Stromag, a leading brand of Altra Industrial Motion Corp. The company is a globally recognized leader in the development and manufacture of innovative power transmission components that meet even the most challenging industrial requirements. In particular, Stromag has extensive expertise in developing solutions for off-highway and agricultural machines, such as the KHM rugged hydraulic clutches.
In response to the OEM’s request, Stromag engineers quickly developed the KHE dry-hydraulic clutch series, a more simplified design of its popular KHM models. These were developed to be weather-resistant and generate low noise at idle speed. The innovative KHE systems are also equipped with sinter pads to enhance the system’s heat capacity.
All these features are combined in a compact design characterised by a limited number of moving parts. As a result, Stromag was able to offer a lean, economical solution, as requested by the agricultural machine manufacturer. In addition, durability was built into the system. Ultimately the clutches are able to successfully eject the large volume of dust and debris generated during harvesting operations, extending their service life.
The KHE clutches also offer a seamless integration within the belt drive pulley. As a result, the responsiveness and performance of the components when engaging or disengaging the cutting head are improved.
Supporting demanding clutch applications
By collaborating with Stromag, the agricultural equipment manufacturer was able to equip its range of self-propelled forage harvesters with a choice of two dry hydraulic KHE clutches. One features a single friction disc to withstand a maximum torque of 4100 Nm at operating pressures of 28 bar, while a larger setup with two friction discs can support applications with torques of up to 8200 Nm.
These alternatives allowed the OEM to benefit from cost savings of approximately 20% while maintaining optimum performance and reliability. As a result, the company could maintain its competitive edge in the agricultural machinery sector. While the KHE were initially developed for this specific project, the clutches are now available for wider use in off-highway vehicles.