Driving device for safety belt tensioner

Abstract

The invention relates to a safety belt tensioner driving device for tightening of a safety belt which can wind around a winding shaft. The safety belt tensioner driving device comprises a main shaft driven by a driving unit and a worm transmission device with a worm and a driven wheel. The worm is installed on the main shaft in a non-rotating mode. The driven wheel is installed on the winding shaft in a non-rotating connecting mode and is engaged with the worm. According to the invention, the worm includes a first tooth segment in the shape of a first toothed gear, and at a first position of the worm, the first tooth segment is engaged with the driven wheel. The worm includes at least one second tooth segment in the shape of a second gear. The second tooth segment is behind the first tooth segment. The shapes of the two tooth segments are designed to be identical. Axial displacement between the first position and the second position occurs to the worm when the worm is under an axial force. At the first position, the worm is engaged with the driven wheel through the first tooth segment. At the second position, the worm is engaged with the driven wheel through the second tooth segment.

Description

technical field [0001] According to the preambles of the claims, the invention relates primarily to a seat belt tensioning drive for tensioning a seat belt that can be wound around a winding shaft. Background technique [0002] Such a reversible belt tightening drive is known from German patent DE102008048339A1, in which an electric motor drives a main shaft via a first transmission (specifically a helical gear transmission) via a second transmission on its side. The second transmission drives a drive wheel non-rotatably mounted on the take-up shaft to wind up the seat belt. This second transmission consists of a screw mounted on the main shaft and an external helical gear that drives the wheels. [0003] The reversible seat belt tensioner is activated in different situations, e.g. in the event of minor or life-threatening impacts, off-road driving or rapid braking and deceleration of the vehicle. tight. To keep the seat belt tensioned in these situations, the electric mo...

AI Technical Summary

Problems solved by technology

Such loads lead to high torques in the driving phase (holding phase) of the belt tensioner, resulting in high meshing forces, especially when the gear members used are external helical gears, resulting in high axial forces, which This high axial force can cause deformation of the meshing components such as the gear body and the bearings in the seat belt tensioner housing, thus possibly leading to reduced stability and ultimately damage to the meshing components and a reduction in mechanical properties

Images