The mechanical part of the electrical steering column (EPS) is telescopic and consists of two sections.It makes a crucial contribution to preventing the steering wheel from moving back dangerously during frontal impact.The lower section includes a sliding sleeve to maintain the steering wheel position fixed during impact.The max sliding load is 8 Kg and is produced by means of an injected plastic insert.The upper section, added to allow the steering wheel position to be adjusted, is:- sliding for axial adjustment (where fitted)- rocker for vertical adjustment (where fitted)The steering column is supported by a steel mounting, in turn secured to a steel bracket. The stiffness of these components contributes signficantly to minimising steering wheel vibrations.All this allows the following objectives to be achieved:- vehicle passive safety- driving comfort
A further contribution to safety comes from the collapsible steering column. The steering column collapses during an impact determining the controlled absorption of the energy. This produces a considerable reduction in the load on the chest of the occupant during an impact.This collapsible feature is achieved through:two detachable elements:the securing bracket has two capsules (1), which are fastened to the actual bracket through a plastic injection which allow the release of the upper section of the column from the crossmember under the dashboard;from the sliding of the upper part of the column:the movement is created through the telescopic sliding of the column tubes and shafts.
The collapsing system has two additional features that contribute to improving the behaviour of the column during a crash:Deformable or collapsing bands (2):their function is to regulate the collapsing load; through the deformation of the bands the energy transferred from the driver is transformed into the band deformation energy. In this way the deceleration of the driver''s torso during the impact takes place gradually.
Positive lock:the column is equipped with a system that secures both the angular and the telescopic position during the event. The system is produced by a toothed insert (3) which engages with the retraction bracket and the compression bracket (4). In order to ensure the correct operation of the system during normal usage with the adjustment of the column (avoid hearing clicks during the adjustment) the adjustment system is fitted with:for telescopic adjustment:a plastic insert (5) fitted on the lever bolt which, with the lever released, keeps the teeth far apart. With the lever closed the teeth mesh with one another again;for angular adjustment:plastic inserts (6) which deform on impact and which release the movement of the axis of the lever letting the insert teeth mesh in their seats in the retraction bracket.
