2. OPERATING PRINCIPLE

2.1 POWER TRAIN OF REAR AXLE

As the 7 spiral bevel pinion shaft (6 spiral bevel pinion shaft) (1) rotates by the range shift gear, the power is transferred to the 35 spiral bevel gear (2), differential case (3), differential pinion (4), differential side gear (5), 9 gear shaft (6), 56 gear (7) and rear axle (8) in order.

The section (A) in the above figure is the differential system that adjusts the speed ratio of LH and RH wheels automatically as needed.

If two racks with same weight are set between the pinion as shown in the figure (A) and the pinion is lifted by pulling up the string attached to it as shown in the figure (B), the pinion does not rotate and the pinion and both racks are lifted in the same height (H).

If the tractor moves forward and the loads on the both wheels are same, the differential pinion (3) idles with the differential case (4) to run the differential side gear (5). In this case, the rotating speed of the ring gear (1), differential case (4) and the both side gears (5) is same. When cornering, the load applied to the both differential side gears are different since the outer wheels should rotate faster than the inner wheels. Therefore, the differential pinion rotates and idles simultaneously to operate the side gear with low load faster and the side gear with high load slower for comfort cornering.

However, if putting a weight only on one rack and lifting the pinion, the pinion rises as it rotates as shown in the figure (C). The rack with a weight keeps its position and the other rack without a weight rises in the amount of the height that the pinion moves and the pinion pushes up the rack. Therefore, this rack rises in double amount of the height that the pinion moves (2H). In this case, both racks refer to the differential side gears and the pinion refers to the differential pinion. Also, the force that pulls up the pinion is the rotating force of the ring gear.

However, if the wheels on one side are on the slippery road, the load difference between both differential side gears remarkably increases and the self-rotating speed of differential pinion (3) considerably increases too. Therefore, the side gear (5) with very low load rotates at twice the speed and the side gear (6) with comparatively high load does not rotate at all. In other words, it is not possible to escape the pit since the wheel on ice with no friction rotates at twice the speed and the wheel on road with friction does not rotate.