PulShaft: Hybrid drive shaft onehot manufacturing and assembly
Themes: Building & Construction, Leichtbau
At the Fraunhofer IGCV - building an the research project PulForm  - a near-series process chain was developed for the production of a drive shaft with a hybrid shaft-hub connection (SHC).
Starting point is the pultrusion, in combination with a B-stage resin system, along with a subsequent blow molding the default simple profiles are formed into complex geometries. Innovation core is the creation of a drive shaft, including all metallic structural elements in one process step. The process step thus not only unites the shaping of the CFRP shaft, but also includes the assembly.
The process chain is divided into the following sections: laminate construction, pultrusion, preform, and blow molding:
- Laminate construction: Consisting of two +1- 30 ° meshes, which are inline in the Pultrusion process, for additional rigidity more than 50% unidirectional fibers are used for the drive shaft.
- Pultrusion: A B-stage resin system (Daron 41, AOC Aliancys) is used. By default, manufactured pultrusion profiles are not deformable, as they are completely cured. By using the B-stage resin system, the Preforms are in a rubbery state after the pultrusion process.
- Preform: By hand force, the preform can be deformed. lt is not sticky however it still has its consistency. lt can be stored at room temperature, or it could also be processed directly.
- Blow molding: The preform including inserted blast hose and metallic structural elements are inserted into the blow molding tool. After closing the tool, it will be under pressure and temperature. The preform is widened in its desired geometry and hardened.
The SHC is realized via a non-positive circular-wedge connection. To connect the metallic structural elements, they are rotated against each other. Thereafter, the SHC can be loaded in both directions with up to 80% of the tightening torque.
In summary, a highly automated process chain was developed, which produces a hybrid drive shaft for a single-stage gearbox. The shaft has a length of 500 mm and has a SHC in three areas.