A manual transmission conventionally has a shift rail which is movable in two degrees of freedom. Due to a movement in one of these degrees of freedom, the shift rail is brought into engagement with one or more synchronizing devices required to engage a gear and due to the movement in the other degree of freedom, this drives an adjusting movement of the respectively selected synchronizing device. These movements must substantially take place successively since the engagement of the shift rail must be made before its adjusting movement can be driven. In order to assist the driver during shifting and to ensure that selection and shifting movements are executed correctly one after the other, mechanical shifting devices conventionally have a link, in which a gearshift/selector lever coupled to the shift rail of the transmission is guided in shifting and selecting tracks which are orthogonal to one another. There are shift-by-wire shifting devices, which also use a gearshift/selector lever which is movably guided in a link in two degrees of freedom and which control the shift rail proportionally to the movement of the gearshift/selector lever in order to offer the driver the handling to which he is accustomed from mechanical gear shifts.
While in a mechanical shifting device, the driver may experience a resistance of the transmission to an unmatched shifting movement and can match the track along which he guides the gearshift/selector lever to this resistance, this is not possible in a shift-by-wire shifting device. In order to reliably eliminate a shifting movement which the transmission cannot follow, the link guiding the gearshift/selector lever must therefore have a narrow tolerance in a shift-by-wire shifting device. This makes a shifting process with track change laborious for the driver since the gearshift/selector lever cannot be moved in one stroke from one gear position into the other gear position but must be halted on the way twice at precisely the correct position to change the direction of movement.
In view of the foregoing, it is at least one object of the invention to provide an external gear shift for a shift-by-wire shifting device with a link-guided gearshift/selector lever, which allows rapid, convenient shifting. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.
USPTO Backgrounds
USPTO Backgrounds