The lifetime of assembly lines is increasingly reduced by shorter model cycles or more frequent changes in design. Therefore, a semi-automatic assembly line is often the best solution when you look at the bigger picture drawn by the investment costs, running costs, necessary cycle times, and model-dependent output.
The semi-automatic suspension strut assembly system bears the advantage that between the tensioning of the coil spring and the secure bolting of the flange bearing, no manual intervention is necessary or even permitted. The suspension struts can be mounted with different actuation lengths using movable shock absorber mounts.
One left and one right shock absorber are placed in the tensioning unit of a vertically movable console, where rubber buffers, bellows, the spring, and axial bearings are mounted to it. Once the centring pins have been placed on the shock absorbers, the axial bearing is aligned with a centring bell. Now the console lowers and tensions the spring with the centring bell and the axial bearing.
Two lockable claws then tension the flange bearing to a tight fit. Once the console is lifted again, a worker can remove the centring bells and pins. The flange bearings can then be placed on the axial bearings and the nuts are threaded onto the shock absorbers.
The nuts are automatically tightened when the screw spindles are lowered onto them. Counterholders to take up the tightening torque are integrated in the screw spindles and inserted into a hexagon socket in the shock absorber.
Audi uses systems of this type as well as complete assembly lines in Györ, Ingolstadt, and Neckarsulm.