CLIMATIC TESTING Geared up for endurance
Jonathan Newell finds out how Pailton Engineering ensures its steering gear boxes can endure the rigours of freight and military transport whatever the weather.
❱ ❱ The bevel box translates steering input through ninety degrees whilst maintaining low torque input from the driver
oventry-based steering system manufacturer Pailton Engineering has recently introduced the third generation of its Bevel Box, the gearing system that translates steering wheel input into on-the-ground wheel direction.
Bevel boxes are a pivotal component of a steering system,
transmitting torque through 90° in order to provide a compact steering system package. The Generation three bevel box was launched to improve on previous designs. The design objectives in moving to the next generation of the product included a reduction of torque to improve ease of steering and to tighten up its climatic resistance. The bevel box is used in heavy goods vehicles, public transport applications and demanding military vehicles across the globe.
CLIMATIC TEST To assure its resistance to harsh environments, the Gen III Bevel Box was subjected to a 56-week-long test programme, the findings of which showed that after a sustained period of submersion, salt and grit exposure at temperatures as low as -40°C, no trace of water had entered the vital component and the part maintained its smooth operation. This has huge implications for vehicles being used in sub zero climates. According to Pailton Engineering’s design and development engineer, Emma Cygan, the testing of the company’s latest bevel box was conducted on a brand new, bespoke test station. This involved submerging the generation three bevel box in salt water for extensive periods of dynamic testing and evaluation. “The bevel boxes were subjected to dynamic submersion and low temperatures so quite frankly, we abused them. We wanted to see if the sealing design features, such as the serration cover and outer full cover, could endure this continual operation, salt and grit exposure and incredibly low temperatures, all while keeping water out of the component. We knew if the bevel box could handle this, then enduring real world extremes would be easy,” explains Cygan.
VERIFICATION TO STANDARDS To independently verify the company’s own test results and to complement the tests that had already been done, Pailton also sent the bevel box to external testing facilities. During these further tests, the bevel box was verified as
meeting the internationally recognised ASTM B117 salt testing standard as well as demonstrating conformance to IP66 and IP67 ingress protection levels.
FLUID VISCOSITY Operating gear boxes at low temperatures can bring about issues associated with the viscosity of the fluid in lubricated components. However, the low temperature lubrication selected for the generation three bevel box can handle a temperature range of -40°C to 80°C, maintaining its low friction capabilities throughout the vehicle’s lifespan. The implication of this is that the component has a much lower running torque of 30 Ncm throughout the expected operating temperature range and resulting in minimal steering effort for the driver. Both on and off the road, the new bevel box design will provide increased protection for the crucial function that it performs. This will reduce the environmental impact on military vehicle operations as well as bus and freight operations in diverse climates, particularly across the cold regions of the United States of America, Europe and Canada. As well as low temperatures, Pailton Engineering can provide protection in different climates during the manufacture of the generation three bevel box to meet the specific requirements of any vehicle application.
Climatic & Vibration Testing 2018 Vol 1 No. 2 /// 5
❱ ❱ The generation three bevel box was subjected to a 56 week long test using a bespoke climatic testing rig at Pailton Engineering
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