BPW hub and suspension technology in the spotlight
Trailer technology provider BPW has described some of the main features and benefits of its hub and suspension systems.
“Developed in the early 1990s, BPW’s Eco Hub system represented a milestone in economical trailer operation,” said the company.
“The complete wheel and hub unit can be removed using a central threaded connection and the DIN ISO tapered roller bearings used can be replaced easily and inexpensively if required, without having to fit a completely new hub.
Specifically designed to cope with high duty cycles of modern transport equipment at low maintenance levels, its innovative features provide a boost in terms of mileage and economy, says the firm.
“This achievement has been met by close attention to key areas such as stub axle, bearing selection, sealing arrangements, lubrication development and bearing adjustment.”
Removal of the patented Eco Hub is simple, says BPW.
“Once the hub cap is removed it allows access to the axle spindle nut and locking device. The axle nut acts as a puller; and by unscrewing this nut anti-clockwise until the thread disengages from the axle stub, the complete hub with bearings, seals and spindle nut can be easily removed. Bearing, seals and lubricant remain undisturbed in the hub.
“There is no bearing free play required – a bearing preload must be set. With the Eco Plus hub system, BPW designers came up trumps again.
“To eliminate the potential of under or over-tightening the hub bearing, the spindle nut has an integrated torque limiter. It is a simple but ingenious design, with the nut slipping as soon as the required pre-set is achieved.”
BPW offers two types of air suspension for 9-tonne axles – the cast trailing arm of the Eco Air and the conventional sprung steel trailing arm of the Airlight ll Round.
“Air suspension maintenance very often receives cursory attention within the statutory periodic inspection cycle,” said the company.
“However, it is an important sub-assembly and is responsible for connecting the trailer chassis to, and distributing the load onto, the axle.”
In an air suspension system, says BPW, the axle beam is an important component.
“The connection between the axle beam and the trailing arm is key to the performance of the suspensions.”
BPW supplies assembled axles and suspensions to trailer builders. This enables inclusion within the five-year warranty (three years for vehicles that travel off-road) of both ‘U’ bolts and spring seats, the firm explains.
Both suspensions, Eco Air and Airlight ll Round, provide the same physical properties, allowing BPW to offer solutions to cater for different types of trailer design and operating conditions.
The company added: “The design of a suspension system is generally a compromise, and this is more so on a trailer where the difference in ground weight varies so much between unladen and fully laden.
“It is really important to ensure that the tyre is kept in contact with the road at all times as this is all that gives the vehicle its braking adhesion and lateral stability.”
BPW Eco Air is the new generation of running gear for on- and off-road use. A patent-pending high-tech laser process means that BPW’s typical clamped modular air suspension mounting can be combined with a round axle beam for the first time.
This provides maximum sturdiness and cuts the weight of a tri-axle suspension unit by 27 kilograms, as compared to the old version of the Eco Air Compact.
With the Airlight II Round, a new feature is the combination of the clamped spring seat arrangement in conjunction with a round axle beam, made possible by the patent-pending laser processing of the contact surfaces in the spring seat arrangement.
This extremely robust mounting, combined with a round axle beam used in both 9 tonnes on-road and off-road applications, enables off-road weight savings of up to 60 kilograms compared to previous versions, says BPW.
