This results in a direct contact of the bearing and the shaft face with the housing which will have a serious operational effect and also a damaging effect on the gearbox cover. In this case, a sleeve was used to eliminate the axial movement of the gear. However, it was noted that there was a very considerable clearance between the sleeve and shaft that could result in eccentric loading on the ball bearings. These mountings of the gears on the shafts clearly indicate that they were manufactured by one who has no knowledge of the rudiments of machine design. Such kind of mounting would result in serious malfunctioning of the drive unit and its lifetime will be considerably reduced.
All bearings employed in the gearbox are deep groove ball bearings.
These particular types of ball bearings have high degree of conformity between balls and grooves and they give no allowance for misalignment of shafts. When bearings are mounted on shafts and housings, they must satisfy the tolerance requirement for the intended purpose. For example, tolerances for gearboxes of this type are k6 and M6. The k6 designation specifies that the shaft diameter is greater than the inside diameter of the bearing. This implies that the fitting between shaft and inner race of bearing is one of interference fit which could require considerable force on the inner race or heating the bearing in a bath of oil to insert the bearing on the shaft.