https://www.moremhod.info/index.php/library-menu/34-strana-kotoroj-bolshe-net/243-neizvestnyj-tank
I found some interesting material, so I’d like to share it with you.
This book seems to be an introductory textbook for Soviet tank crews, and explains the technical aspects of tanks.
It’s all in Russian, but I think you can read it with machine translation.
Also… there are some political claims here and there that are questionable, but the technical information seems reliable.
This textbook explains the definition of a “regenerative steering system.” It is described as “a mechanism that creates a speed difference between the left and right tracks, which is necessary for turning a tracked vehicle, by distributing energy alone, without using external resistance such as brakes.”
In the WT community, a regenerative steering system is described as one in which the outer track accelerates when turning, but this is not the essence. For example, if the speed of the inner track is reduced by some kind of gear reducer, it becomes a regenerative steering system. In this case, the horsepower required is reduced by the amount that the inner track slows down, giving the engine room to rest. The angular velocity when turning with this method is almost the same as with the clutch and brake, but the horsepower required at the same angular velocity is lower with the gear system.
In the “double differential steering” used in modern MBTs, the horsepower lost by lowering the rotation speed of the inner track is used to increase the rotation speed of the outer track. Therefore, the engine load does not change when a speed difference is generated.
Compared to a gear reduction type steering device, the double differential type can increase the speed difference between the left and right tracks, so it is thought that the angular velocity will be larger.
However, the outer track, whose rotation speed has increased without changing the horsepower from the engine, loses torque in exchange for the rotation speed. As mentioned above, tracked vehicles are exposed to heavy loads when turning. A decrease in torque in this state is inconvenient for turning.
In fact, textbooks state that the double differential has little advantage compared to its complexity. In order to turn normally, the main transmission must be lowered by one step to generate torque, and the advantage of increased angular velocity is thought to be relatively lost.
However, modern MBTs developed after this textbook often have built-in torque converters. This type of MBT is configured with a very wide-ratio transmission and torque converter, and is thought to be able to flexibly deal with torque shortages due to the double differential.