BMW commits to GKN's new CV joint

GKN Driveline has been able to reveal itself as vendor of choice for new lightweight constant velocity joint (CV Joint) system in the BMW 7 Series, production of which began over six months ago at Plant Dingolfing, Germany.

The new lightweight CV joint enables rear-wheel drive platforms to save over 4kg in weight.

The 7 Series is the first application of the new VL3 CV joint which increases torque capacity by up to 27 per cent with no increase in packaging size.

Available in four sizes, automakers alternatively have the choice of maintaining torque capacity but reducing package size by 10 per cent. Other high-end OEMs are likely to follow..

With a plunging distance of 18mm, the VL3 is suitable for a rear constant velocity side-shaft for medium working angles with low axial forces. GKN claims it gives best in class minimum backlash.

The new joint uses a Monobloc Tubular Shaft and Face Spline connection to the wheel hub to achieve significant packaging and weight advantages. Noise, vibration and harshness (NVH) behaviour also benefits giving a more refined driving experience.

GKN pioneered the more-efficient CounterTrack principal on fixed joints starting in 2009 and the VL3 joint further builds on this success by introducing the technology on a rear side-shaft.

The VL3 joint uses a new and innovative track geometry with four pairs of opposed ball tracks instead of three. Although more expensive the configuration enables the CV joint to transmit more torque to wheels within the same packaging space.

The joint is further enhanced through the use of a diaphragm boot sealing system, instead of a standard boot and cap. This helps reduce axial packaging, grease volume and weight.

Karl Berger, GKN Driveline senior director product technology of constant velocity joints, said proudly: “GKN already established the benchmark for rear CV Joints with our predecessor technology, but the VL3 sets the new level. We have developed a CVJ that is lighter, more efficient, stronger and delivers more torque in smaller packaging.

“The VL3 joint helps automakers achieve a refined, luxury driving experience. We are delighted that it is debuting on the BMW 7 Series,' he claimed.

Berger added: “GKN has pioneered the development of CV joints for over 60 years.  These latest innovations offer improvements in every area of importance for automakers, including strength, endurance, efficiency and weight, helping to produce a dynamic driving performance and optimising power delivery from the engine to the wheels. We have also minimised backlash, which leads to a refined driving experience.”

BMW’s Plant Dingolfing started life anew in 1967 when the company acquired the former medium size car company “Hans Glas GmbH”.

Plant Dingolfing is the largest of all BMW plants and one of the biggest factories in the world. Thousands of associates and machines produce the medium and large models of BMW.

The plant employs 17,500 as well as 800 apprentices. Daily output is 1,600 vehicles based on 3 Series GT, 4 Series Gran Coupé, 5 Series (Sedan, Touring and GT), M5, Active Hybrid 5, 6 Series (Coupé, Convertible and Gran Coupé), M6 (Coupé, Convertible and Gran Coupé), 7 Series (Sedan, Active Hybrid and High Security). The plant also makes various vehicle components.