| ThyssenKrupp and Johnson Controls
have developed a prototype cockpit that dispenses with the usually critical
crosscar beam. The mixed use of steel and plastic cuts weight by one-fifth
without compromising safety – crash performance is not affected,
say the firms.
The crosscar beam is an important part of a vehicle’s structural
strength. Running across the width of the car, it is also useful for mounting
the instrument panel and reinforcing the steering column area.
The suppliers’ EcoSpace composite steel and plastic structure is
20 per cent lighter than a standard beam and instrument panel, but it’s
controversial.
The metal is on the driver’s side; the passenger’s side is
predominantly just plastic. Such structures are usually made of steel,
magnesium or aluminium.
ThyssenKrupp Steel project manager Martin Hinz said: “Crash performance
is the same on both sides, regardless of whether where the impact takes
place. The deciding factor is the precise interaction between the plastic
and steel.”
ThyssenKrupp simulated crashes from the front and side and Johnson Controls
examined the effects of a crash on the whole cockpit. The structures meet
the regulatory requirements, such as EuroNCAP crash test standards and
FMVSS 208 for the US.
The engineers took an unusual approach to reinforcing the steering column
area – they used a tripod, constructed out of tailored steel tubes.
It simplifies the often-complex steering column connection and could create
extra space for passenger protection.
”It’s the most stable structure that allows for minimum material
use. The tripod is screwed to the cowl, the A-pillar and the floor,”
said ThyssenKrupp Steel.
ThyssenKrupp Presta took care of the work on the steering column, attaching
it directly to the steering column. Doing this in a way that optimises
the flow of forces in an impact was not easy, however.
“Traditional construction needs seven parts to achieve this. Ours
has just one,” said the firm. Overmoulded steel inserts laser-welded
to the tripod connect the steel and plastic substrate.
Johnson Controls developed the instrument panel and cockpit components.
Senior product manager Thomas Beer said: “Concentrating the main
structure on the driver side gives the option for different layouts, particularly
on the passenger side. It also significantly reduces the assembly complexity
– all the OEM has to incorporate are individual components such
as the radio and air conditioning.”
The team of engineers took a steel structure from a high-volume lower
medium segment vehicle as a benchmark for their concept. Hinz said: “Our
aim was to simplify assembly for OEMs by offering a single-source cockpit
structure.” |
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