Patent ID: 8506444
Filing Date: 2013-08-13
Classification: F16H

Abstract:
1. A multi-speed automatic transmission of a planetary design for a motor vehicle, the transmission comprising: a transmission housing; an input shaft; an output shaft; a first planetary gear set, a second planetary gear set, a third planetary gear set and a fourth planetary gear set; each of the first, the second, the third and the fourth planetary gear sets comprising three elements; a first shifting element for releasably connecting one element of the first planetary gear set and one element of the fourth planetary gear set to the transmission housing; a second shifting element for releasably connecting one element of the first planetary gear set to the transmission housing; a third shifting element at least for releasably connecting one element of the third planetary gear set to the input shaft; a fourth shifting element for releasably connecting one element of the second planetary gear set to one element of the third planetary gear set; and a fifth shifting element for facilitating interlocking of the second planetary gear set, when the fifth shifting element is engaged, so that the three elements of the second planetary gear set rotate in unison with one another at the same rotational speed; wherein the input shaft is directly connected to one element of the fourth planetary gear set so as to constantly rotate in unison therewith; the output shaft is directly connected to one element of the third planetary gear set so as to constantly rotate in unison therewith; a third shaft directly connects one element of the first planetary gear set with one element of the fourth planetary gear set; a fifth shaft directly connects one element of the second planetary gear set with one element of the third planetary gear set; a sixth shaft directly connects one element of the first planetary gear set with one element of the third planetary gear set; and a seventh shaft directly connects one element of the second planetary gear set with one element of the fourth planetary gear set.