This tapered roller bearing design employs 3 stacked layers of tapered rollers such that any two consecutive tapered rollers with the same one layer of rollers are kept separated, a small distance apart, so that they cannot come into contact and rub against each other, causing friction and load.
The rollers are significantly slanted downwards (or, depending on your point of view, upwards) towards the centre of the bearing so that their round, rolling surfaces pick up a significant component of both radial and axial forces which the bearing may experience during use.
The bearing's rollers are tapered rather than uniform cylinders and are arranged in a radial pattern such that their respective axes of rotation all point to a common convergence point in the middle of the bearing.
The middle layer of rolling elements keeps any two consecutive rollers in either of the other two rows separated and, reciprocally, any two consecutive elements of its own are themselves kept apart by rollers in the other two layers.
The middle row of rollers is load bearing as well, conveying load between the other two.
The rolling elements need to be tapered cylinders / truncated cones because their respective axes of rotation are not parallel to the bearing's shaft axis.
Which means that, for each complete revolution of the bearing, the ends of its rolling elements facing away from its centre need to travel a longer distance than their opposite ends, which face towards the centre of the bearing. However, both ends of any one individual roller must spin at the same RPM.
Which means that the diameter of the rollers must be greater at their outward facing ends than their inward facing ends, in direct proportion to the different lengths of distance they must, respectively, travel for the bearing to complete one full revolution.
This bearing should inherently automatically adjust for slight differences (owing to manufacturing tolerances) in the respective diameters of its various rolling elements (as long as the ratio between endpoint diameters is preserved).
It should also inherently automatically spread both the axial and radial load evenly across all of its rollers, due to the rollers positioning themselves into a stable arrangement (which takes up the least amount of space) under load.
An even number of layers of rolling elements cannot be used because they would convey rotation from one of the bearing's surfaces to the other, defeating the purpose of the bearing and that of using rolling elements inside of it.
And a single layer of rollers would be no different from tapered roller radial-axial bearings currently in widespread use, which exhibit sliding contact either between consecutive rollers in the one layer of rolling elements or have sliding contact with a cage which keeps them separated from each other but which they all slide or rub against, contributing to friction, heat and wear.