Method for determining the rotational speed of the main shaft of a transmission, and transmission comprising a device for detecting rotational speed

A transmission assembly for determining rotational speed and rotational direction of a main shaft (3) and an output shaft (4) of a transmission (1), the assembly comprising:

• a planetary gearset (17) having a sun gear (18), a ring gear (22) and a planet carrier (20) supporting planetary gears (19), the sun gear (18) being coupled to the main shaft (3) in a rotationally fixed manner, the planet carrier (20) being coupled to the output shaft (4) in a rotationally fixed manner;
• the ring gear (22) having a plurality of exterior teeth (28) and the planet carrier (20) having a plurality of exterior teeth (29);
• a sensor module (23) having
• a first rotational speed sensor (24) and a first rotational direction sensor (25) for detecting speed and rotational direction of the plurality of exterior teeth (28) of the ring gear (22), and
• a second rotational speed sensor (26) and a second rotational direction sensor (27) for detecting speed and rotational direction of the plurality of exterior teeth (29) of the planet carrier (20);
• and
• a computing unit (31) communicating with each of the first and the second rotational speed sensors (24, 26) and the first and the second rotational direction sensors (25, 27) for receiving signals therefrom and calculating the rotational speed and the rotational direction of the main shaft (3) and the output shaft (4).