Motor vehicle transmission for an at least partially electrically driven motor vehicle

A method for operating a motor vehicle, comprising:

• providing a drive unit comprising:
• a first electric machine having a rotor;
• a second electric machine having a rotor;
• a first drive input shaft coupled to the rotor of the first electric machine;
• a second drive input shaft coupled to the rotor of the second electric machine;
• a drive output shaft;
• and
• a first planetary gearset and a second planetary gearset each having, respectively, a first element, a second element, and a third element in the form, respectively, of a sun gear, a planetary carrier, and a ring gear;
• a first shifting device and a second shifting device each configured to engage various gears;
• wherein the first shifting device comprises a first coupling element which can be positioned in precisely two gear engagement positions and in a first gear engagement position the first coupling element immobilizes the first element of the second planetary gearset;
• wherein the first element of the first planetary gearset is connected rotationally fixed to the first drive input shaft and the third element of the first planetary gearset is immobilized;
• wherein the second element of the second planetary gearset is connected rotationally fixed to the drive output shaft;
• wherein the second element of the first planetary gearset is connected rotationally fixed to the third element of the second planetary gearset;
• and wherein the second shifting device comprises a second coupling element which can be positioned in precisely two gear engagement positions, such that in a first gear engagement position, the second coupling element connects the first element of the second planetary gearset in a rotationally fixed manner to the second drive input shaft, and in a second gear engagement position brings the first drive input shaft into a rotationally fixed connection with the second drive input shaft;
• and
• wherein the first coupling element in the second gear engagement position connects the first element of the second planetary gearset in a rotationally fixed manner to the second element of the second planetary gearset;
• engaging a first gear between the first drive input shaft and the drive output shaft by moving the first coupling element to its first gear engagement position, wherein engaging the first gear includes moving the first coupling element to the first gear engagement position and moving the second coupling element to the second gear engagement position;
• engaging a second gear between the first drive input shaft and the drive output shaft by moving the first coupling element to the second gear engagement position, wherein engaging the second gear includes moving the first coupling element to the second gear engagement position and moving the second coupling element to the second gear engagement position;
• making a change under load between a first gear acting between the first and second drive input shafts and the drive output shaft of the motor vehicle transmission, and a second gear acting between the first and second drive input shafts and the drive output shaft of the motor vehicle transmission, wherein making the change includes carrying out a switch-over in the second shifting device of the motor vehicle transmission by moving the second coupling element from the second gear engagement position to the first gear engagement position of the second coupling element;
• carrying out, during the switch-over in the second shifting device, a rotation speed synchronization in the second shifting device by the second electric machine while a traction force is supported by the first electric machine;
• moving the first shifting device of the first coupling element out of its current gear engagement position to its neutral position, thereby producing, by interaction of the two electric machines, a load-free condition of the first coupling element;
• after that, in the first shifting device, moving the first coupling element of the first shifting device out of its neutral position to its target gear engagement position, and thereby carrying out a rotation speed synchronization in the first shifting device by the first electric machine;
• and
• carrying out a switch-over of the second coupling element in the second shifting device from the first gear engagement position to the second gear engagement position of the second coupling element and during the course of the switch-over, a rotation speed synchronization is carried out in the second shifting device by the second electric machine and a traction force is supported by the first electric machine.