Shaft retention screw for commercial vehicles

A steering assist system for a commercial vehicle, the steering assist system comprising:

• an input shaft defining an input axis and a first hollow portion, the input shaft configured to engage with a steering column of the commercial vehicle;
• an output shaft defining an output axis and a second hollow portion, the output shaft being disposed within the first hollow portion coaxially to the input shaft, the second hollow portion defining internal threads;
• an output shaft adapter defining a third hollow portion extending through the output shaft adapter axially, the third hollow portion having a smaller diameter region at a first end and a larger diameter region adjacent to the smaller diameter region, a shoulder being defined at a transition between the smaller diameter region and the larger diameter region,
• wherein the output shaft adapter is disposed at the first end of the output shaft such that the smaller diameter region circumferentially surrounds the output shaft;
• a support plate including a bearing configured to receive the output shaft adapter and guide rotation of the output shaft adapter;
• a worm wheel circumferentially surrounding the output shaft adapter, the worm wheel having an outer circumference configured to engage a worm shaft for steering assist;
• and
• a shaft retention screw having a head portion defining a flange and a body portion defining external threads, the shaft retention screw being disposed in the third hollow portion such that the flange engages with the shoulder and the body portion extends into the second hollow portion such that the external threads engage with the internal threads of the output shaft so as to prevent axial separation between the output shaft and the output shaft adapter.