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Power-dividing, adjustable transmission The known finely-tuned or infinitely variable torque converters do not meet all the requirements for good efficiency, low weight, and portable price. It is obvious and has also been attempted to provide amelioration by branching gears in which only part of the power is routed through the variable speed gearbox and the other via a gear ratio. Fig. I shows such a branching gear. The power introduced at A is divided into branch I and branch 2. In I is a controllable torque converter. Both branches are combined in a differential gear to the output B.

The advantage of such an arrangement is obvious; a poor efficiency of the torque converter is only partially felt in the overall efficiency, the heavy and expensive converter can be reduced to the detriment of the light, cheap and low-loss branch with a fixed gear ratio. These advantages compared to it is immaterial if the control range, ie the ratio of the largest to the lowest output speed, hereinafter referred to as R, of the variable transmission branch must be greater than that achievable in the overall transmission; because there are several known converters that control speeds from zero up, so where R is infinite. It is essential, however, that the control range R, of the overall transmission with the ratio V of the power in the controlled branch r is linked to that in the branch 2 by a relationship that limits the application of the previously known branching gears to special cases. If, in the control branch I, one allows only power flow in one direction (from A to B), the power in branch I at the one end of the control range is, at best, zero. Then at the other end in the lossless transmission V = Rg - I.

When the largest to the smallest torque or the largest to the lowest speed behave like 2: I, the performances of both branches are already equal. The practical, approximately in crane or vehicle operation, usable control range 4: I conditionally V = 3, ie the control branch I must be designed for 75% of the total power. Since even the trickiest series connections of power split can not escape the compulsion of the above equation, the application of the known branching transmissions brings only in the few cases advantages in which a very small control range is sufficient.

The inventive idea brings a branching gear, which is free from the constraint of the said equation. The overall performance of the transmission is divided, for example, according to Fig. 2 in more than two adjacent power branches. Branch I is again formed by a control gear. This may be an electrical or hydraulic torque converter, a Schaltwerkss-, friction gear, etc., or a variable-speed transmission as the known gear multi-speed transmission. The power branches with fixed gear ratio are designated 2, 3, 4.

In the case of this transmission, with the above designations, in the case of the said practically usable control range 4: I is V = ½, once again permitting only the flow of power in one direction; through the control gear so only a third of the total output. Assuming the control part for maximum load of half the total power, Rg = 9: I; a torque conversion to nine times the normal torque can not be used in general.

Another advantage of the arrangement according to the invention is that the Nulleistung of the control part can be placed at both ends of the control range, ie both in the region of highest torque and the highest speed and the maximum power taking advantage of the short-term overload capacity in the range of the lowest load time. Fig. 4 shows in a the characteristic of the known branching gear, in b an inventive arrangement for a Rg = 4th Fig. 3 shows a modification of the arrangement (Fig. 2) in an equiaxed transmission. The controllable power branch I is an electric motor-generator converter.

From the arrangements shown it is easy to develop further in which several power branches are connected next to branches with a fixed ratio.