Products and solutions, 2006-09-27, 10:59 AM
Innovative development with integrated approach
At IAA Commercial Vehicles 2006, ThyssenKrupp Automotive is presenting a design study for an independent suspension system for heavy trucks. The key feature is the vendor-independent, holistic approach which integrates the frame structure on the basis of the topological optimization of the frame and axle structure elements.
Based on current truck market requirements, clear trends for the future can be identified in the area of suspensions. Handling properties are only one criterion in the design of future suspension systems. As a result of the use of more powerful engines and tighter exhaust regulations, assemblies are becoming increasingly complex and require greater packaging space. Using a solid axle restricts the packaging space available due to the compression and rebound movements, meaning that new axle concepts such as independent suspension are required.
As a competent partner to the auto industry, ThyssenKrupp Automotive recognized this at an early stage and presented a trailing arm design study for medium-duty trucks in 2000, followed by further concepts mainly for heavy trucks. The development steps implemented primarily addressed the axle design. However, it was recognized that the synergies needed to achieve cost and weight targets could not be realized with this approach.
As a consequence, the existing concepts were developed into a holistic approach to the front end, i.e. the weight- and cost-optimized realization of future handling, comfort, crash and packaging requirements.
The independent suspension concept for heavy trucks presented at this year's IAA represents a systematic and innovative advancement of previous developments, realized by concentrating the expertise already available in various ThyssenKrupp Automotive subsidiaries for truck axles, cab suspension systems, steering systems and spring/damping elements.
In addition to the known advantages of independent suspensions with respect to ride comfort through e.g. a reduction in unsprung masses and greater driving safety through more precise wheel control, this solution creates additional packaging space for larger engines and radiators through the space-saving arrangement of the air springs on the upper control arm and optimized kinematics. This makes it easier to meet future emissions requirements for the truck industry.
A further decisive element in the realization of this independent suspension concept is the integration of the frame structure. This has enabled both the special stiffness requirements of the independent suspension as well as the requirements of the vehicle as a whole and crash performance in line with the ECE standard to be taken into account in the design of the load-bearing structure. Further elements are weight optimization through the topological design and the use of ductile sheet metal assemblies made of high-strength materials in the load-bearing structure, as well as a reduction in bearing points through the elimination of the steering knuckle support.
In addition, ThyssenKrupp Automotive is presenting a new generation of cab suspensions, principally of interest for vehicles without independent suspensions. The study represents a concept for future front and rear cab suspensions based on new development ideas for increased ride comfort. The use of a new type of control arm and connection significantly increases ride comfort and generates added value with a well-balanced cost/benefit ratio. As a result of the way the front and rear control arms are arranged and the modified cab lock, the rolling and pitching axis is shifted to the cab's center of gravity which significantly reduces the unwanted rotatory pitching and rolling movements of the cab which occur e.g. when starting and changing gear or on uneven roads.