“Thanks to the close collaboration right at the start of the design process, we were able to develop high quality components at an attractive price. They formed the supporting cast for the successful introduction of a brand new active aerodynamic device from Tier One System Supplier Flex-N-Gate in the world’s best-selling pickup truck,” says Marius Brand, Product Manager Active Aerodynamics at Mirror Controls international, a Flex Company. The company – abbreviated to MCi – is a supplier to the automobile industry and market leader in wing mirror control. It also produces camera monitor systems – and, of course, the controls for the active aerodynamic device. MCi delivers over 80 million appliances annually. With around 1,200 employees, MCi delivers to the major customers of the industry and is an important development partner. The Angst+Pfister collaboration concerned a control element for the aerodynamics of the Ford F-150 – said by the maker to be “the most robust, innovative and versatile pickup truck ever” to leave the production line. To increase the aerodynamics, above a certain speed, air dam is extended from beneath the front bumper of the off-roader, and these are designed to optimally re-direct the air streams. The resulting decreased drag equates to improved fuel efficiency. In the past, this function was performed by a static element – a compromise between optimal wind resistance at higher speeds – and maximum clearance for slower off-road conditions. The new active aerodynamics device, with the air dam retracted, delivers maximum freedom in rough terrain – or lowers fuel consumption on smooth asphalt.
Three components for pioneering aerodynamics
MCi came to Angst+Pfister for the design, production and delivery of two radial shaft seals and a spring bellow unit for the small electric motor controlling the active aerodynamics. The seals are installed in the actuator unit of the system, whereas the spring bellow unit protects the spindle that moves the air dam (see drawing). “This was a very interesting project for us because we were able to demonstrate our strengths: inhouse design, Finite Element Analysis, rapid prototyping, samples, logistics on three continents and mass production volumes – and all this in exceptional quality,” says a pleased Jan Boomsma, Product Application Engineer in Sealing Technology at Angst+Pfister in the Netherlands.
The Active aerodynamics systems have to last and be exceptionably reliable – even for big temperature differences from minus 40 to plus 85 degrees Celsius. The air dam stows and retracts around 300,000 times. The system must also be leakproof when in water. This requires protecting ratings IP67 and IP69K. In other words, it has to be completely dust-tight and even able to withstand high water pressure. The aerodynamics control device is produced in quantities of an annual 1.6 million. It also needs to comply with the PPAP (Production Part Approval Process) of the automobile industry. This is the acceptance procedure by which the parts made in serial production must be exactly as stipulated by the drawings. MCi requires 50 PPM quality – from one million produced parts, only fifty can be rejected. For Angst+Pfister’s seals, this effectively means that we must measure 100% of the parts during quality control with a fully automated sorting machine.
Innovative approaches for reasonable costs
“Of course, the price also played a role. Which made the design a bit of a challenge for us,” remembers Jan Boomsma. Angst+Pfister initially offered a pure rubber seal without metal reinforcement to keep the costs down; the initially designed seals have stainless steel reinforcement. But Jan Boomsma and his team sought an additional solution and integrated carbon steel reinforcement. “That was possible thanks to a specialist design in which rubber coated all the metal parts to prevent corrosion,” relates Jan Boomsma. In this way, Angst+Pfister fulfilled the requirements for high quality plus acceptable cost. As the customer, Marius Brand was impressed by this approach: “We now have an integrated solution with two functions in one component. The upper seal functions both to seal and pretension. In this way an additional part becomes superfluous.”
For the spring bellow unit, the engineers used an EPDM that holds up in low temperatures. The design had to even out the strong bending force from compression and expansion of the spring bellows for reliability to be guaranteed. At the same time, a certain roughness of the upper surface was called for to prevent it from sticking together when compressed.
«This was a very interesting project for us because we were able to demonstrate our strengths: inhouse design, Finite Element Analysis, rapid prototyping, samples, logistics on three continents and mass production volumes – and all this in exceptional quality.»
Jan Boomsma, Product Application Engineer Sealing Technology, Angst+Pfister Netherlands
The prototypes had to be available very quickly. “Normally, you need about ten weeks, we delivered in four,” relates Enrico Koggel, Product Application Engineer at Angst+Pfister in the Netherlands. The fact that all the designs were inhouse designs was particularly advantageous for the Angst+Pfister engineers. After the first tests, the design was refined again to improve its temperature durability. Then the tools for the prototypes could be made right away using the inhouse production platform. MCi put them through stringent testing for durability and installation. Following further optimisation, work on the production mould for the PPAP could be started. As soon as this had been approved, there was nothing stopping serial production from going ahead. Enrico Koggel adds: “Angst+Pfister has several production platforms across several continents so that when things get tricky, other production facilities can be brought in to help out. Notwithstanding the Covid-19 crisis, this was luckily unnecessary.”
Marius Brand of MCi also adds his praise: “The prototype timeline was challenging, but we are very happy with both the quality of the work and the products. They fulfill all the requirements and successfully passed the full range of validation tests.” MCi greatly appreciated Angst+Pfister’s onsite technical support in the Netherlands. This includes, in the various phases of the project, the capability to conduct calculations and simulations with the prototypes, to respond to tests and to adapt the designs correctly, says Marius Brand.
The seals (green) are inside the actuator
housing (beige). The spring bellows (black)
protects the spindle (white). This moves the
air flaps (red).
More information about our Seals and bellows for aerodynamics
published: 8 mar 2022, 14:38:00 by: Angst+Pfister Magazin2022