SINGLE-MOTOR TRANSMISSION ACTUATOR WITH GATE FOR SELECTING AND SHIFTING GEARS OF A MOTOR VEHICLE TRANSMISSION DEVICE

20170152941 ยท 2017-06-01

    Inventors

    Cpc classification

    International classification

    Abstract

    A transmission actuator has gear steps for forming gears and a selector shaft supported rotatably for shifting gears and supported axially movably for selecting gears. The actuator has a gate with a fixed first gate part and an axially movable and rotatable second gate part, the one gate part having slots and lands alternating in a direction and the other gate part having at least one element which can interact with one of the lands at a time and is movable into one of the slots at a time. The element is moved in a prescribed direction past the lands and slots in a selecting motion and is moved into one of the slots in a shifting motion. When there is a collision between element and land during a shifting motion the movable gate part can be moved further in the prescribed direction of the selecting motion by an insertion chamfer and when there is a the movable gate part is not movable contrary to the prescribed direction of the selecting motion, but the shifting motion is stopped.

    Claims

    1-13. (canceled)

    14. A transmission actuator for a motor vehicle transmission device, the transmission actuator comprising: a plurality of gear steps for forming gears; a selector shaft supported rotatably for shifting the gears and supported axially movably for selecting the gears; a gate with a fixed first gate part and an axially movable and rotatable second gate part, one of the first and second gate parts having slots and lands alternating in a direction and the other of the first and second gate parts having at least one element interactable with one of the lands at a time and movable into one of the slots at a time; wherein the at least one element is moved in a prescribed direction past the lands and slots in a selecting motion and is moved into one of the slots in a shifting motion; an insertion chamfer at least on the lands or on the element, so that when there is a collision between the element and the one land during the shifting motion, the second gate part is movable further in the prescribed direction of the selecting motion via the insertion chamfer and the shifting motion can be continued; and right-angled transitions, so that then when there is a collision between the element and the one land during the shifting motion the second gate part is not movable contrary to the prescribed direction of the selecting motion, but the shifting motion is stopped.

    15. The transmission actuator as recited in claim 14 wherein the element has a first wall pointing in the prescribed direction and has an end face pointing toward the one slot, the insertion chamfer being present between the end face and the first wall, and wherein the element has a second wall pointing contrary to the prescribed direction, one of the right-angled transitions being between the end face and the second wall.

    16. The transmission actuator as recited in claim 14 wherein the second gate part has the slots and the lands.

    17. The transmission actuator as recited in claim 14 wherein the second gate part is positioned immovably on the selector shaft and is movable with the selector shaft relative to the fixed first gate part.

    18. The transmission actuator as recited in claim 17 wherein the second gate part has the slots and the lands and is positioned coaxially to the selector shaft and extends around the selector shaft, while the slots and the lands extend in a circumferential direction and the second gate part has in addition at least one track, the one element movable in the at least one track during the selecting motion.

    19. The transmission actuator as recited in claim 18 wherein the second gate part has the slots and the lands on both sides of the at least one track, and in the case of the selecting motion in the first direction the shifting motion occurs only in a first circumferential direction, and in the case of a selecting motion in a second direction contrary to the first direction it occurs only in a second circumferential direction, the at least one element accordingly having two end faces.

    20. The transmission actuator as recited in claim 17 wherein the second gate part is attachable non-rotatingly through first profile toothing on an internal circumferential surface to second profile toothing on an external circumferential surface (26) of the selector shaft, a coding tooth being present on each of the sets of profile toothing that allows only one installation position of the second gate part and the selector shaft relative to one another.

    21. The transmission actuator as recited in claim 20 wherein a marking is positioned on the second gate part so that the installation position is recognizable.

    22. The transmission actuator as recited in claim 18 wherein the first gate part is ring-shaped and is positioned coaxially to the selector shaft, and extends around the selector shaft and around the second gate part.

    23. The transmission actuator as recited in claim 18 wherein the first gate part has two elements of the at least one element located opposite one another and the second gate part has two tracks located opposite one another.

    24. The transmission actuator as recited in claim 14 further comprising a spindle having a spindle nut forming a toothed rack and operatively connected to a shaft gear via one of two gear wheels at a time, the shaft gear being firmly connected to the selector shaft, wherein the spindle nut forms the second gate part and the slots and the lands run parallel to a spindle axis and the element is of the first gate part and is formed by at least one pin.

    25. The transmission actuator as recited in claim 24 wherein the first gate part has two pins positioned parallel to one another and on opposite sides of the spindle axis.

    26. A method for selecting and shifting gears using a transmission actuator as recited in claim 14, wherein a control system is provided and the method comprises the following steps: a. performing the shifting motion and positioning the element in the one slot; b. performing the selecting motion so that the element and the one land are in contact with one another; c. determining a present actual position of the one land or of the element in the direction of the selecting motion; and d. equalizing a target position and the present actual position in the control system and determining wear of the transmission actuator.

    Description

    BRIEF DESCRIPTION OF THE DRAWINGS

    [0038] The invention as well as the technical environment will be explained in greater detail below on the basis of the figures. The figures show especially preferred exemplary embodiments, although the invention is not limited to these. In particular, it must be pointed out that the figures, and especially the depicted size proportions, are only schematic. Like reference labels designate like objects. The figures show the following:

    [0039] FIG. 1: a single-motor transmission actuator from the prior art according to DE 10 2013 207 871;

    [0040] FIG. 2: a detail of FIG. 1 in a view rotated by 90;

    [0041] FIG. 3: an H-shaped shifting diagram as an abstraction of the shifting motion;

    [0042] FIG. 4: a selector shaft with gate and gearshift lever/shift rail in sectional view;

    [0043] FIG. 5: the depiction from FIG. 4 with the gearshift lever in a different position;

    [0044] FIG. 6: a first variant embodiment of a second gate part;

    [0045] FIG. 7: the interaction of a first gate part and a second gate part as a gate;

    [0046] FIG. 8: tracks and slots of a second gate part with elements of a first gate part positioned therein;

    [0047] FIG. 9: the depiction according to FIG. 8 in a different position;

    [0048] FIG. 10: the depiction according to FIG. 8 with the sequence of a selecting motion and a shifting motion;

    [0049] FIG. 11: the depiction according to FIG. 8, with an erroneous shifting motion being stopped here;

    [0050] FIG. 12: a detail of a first gate part according to FIG. 7;

    [0051] FIG. 13: a single-motor transmission actuator shown from the side, in a sectional view;

    [0052] FIG. 14: a detail of a single-motor transmission actuator in a perspective view with a second variant embodiment of a gate;

    [0053] FIG. 15: a detail of the single-motor transmission actuator according to FIG. 14.

    DETAILED DESCRIPTION

    [0054] FIG. 1 shows a single-motor transmission actuator from the prior art according to DE 10 2013 207 871. Using a motor 41, a spur gear 42 is driven by means of an appropriate motor spindle 43; both directions of rotation 44, 45 are possible. The spur gear 42 meshes with the inside teeth of a ring gear 46, which in this case drives a spindle 30 (a threaded spindle) directly. Depending on the direction of rotation of the motor spindle 43 of the motor 41, the spindle 30 also performs a rotary motion in a first direction of rotation 44 or an opposite second direction of rotation 45.

    [0055] A spindle nut 31 is situated on the (threaded) spindle 30. The spindle nut 31 meshes by means of toothing 56 (see FIG. 2) with one of two gear wheels 33, 34 at a time, which themselves are connected by means of a shaft gear 35 to a selector shaft 3. An axial displacement of the spindle nut 31 brings about a rotation of one of the two gear wheels 33, 34. This rotation causes a rotation of the shaft gear 35 and correspondingly a swiveling of a gearshift lever 47, which is located on the selector shaft 3. The gearshift lever 47 interacts with a motor vehicle transmission device, which has a plurality of gear steps for forming gears. The gearshift lever 47 performs a shifting motion 12 with the swiveling motion.

    [0056] If the spindle nut 31 is moved along the spindle 30, the engagement with a third gear wheel 49 is enlarged; that is, areas of overlap are gained. It would also be possible for a meshing to come about only with this motion. As long as the spindle nut 31 is in a first axial position range 50 of the threaded spindle 30 and is meshed with a detent mechanism 48, the spindle nut 31 cannot move axially against the holding force of the detent mechanism 48. A rotation of the selector shaft 3, that is, a shifting procedure, does not become possible until the spindle nut 31 has been moved far enough out of this first axial position range 50 and along the spindle 30 into a different axial range, until the holding force between the spindle nut 31 and the detent mechanism 48 has been overcome. The spindle nut 31 is now connected to the free-wheel mechanism 51 through the third gear wheel 49. The free-wheel mechanism 51 allows a rotary motion only in a second direction of rotation 45, so that the spindle nut 31 is able to perform a rotary motion exclusively in a first direction of rotation 44. Also positioned on the axis of rotation of the free-wheel mechanism 51 is a selector wheel 52, by means of which the rotation of the spindle nut 31 and of the motor spindle 43 is transmitted to a selector pot 53. The selector pot 53 may also be driven accordingly exclusively in one direction of rotation, and with the help of a trajectory 54 on its circumference transforms the rotary motion into an up-and-down motion of guide pins 55, which engage with the trajectory 54 and are connected to the selector shaft 3. The up-and-down motion of the guide pins 55 thereby corresponds to a selecting motion 11 of the selector shaft 3. This selecting motion 11 is carried out as long as the motor 41 is moving in the first direction of rotation 44. If the motor 41 is turning, its direction of rotation stops the selecting motion 11 because of the free-wheel mechanism 51. But the spindle 30 is now turning and the stationary spindle nut 31 moves back along the spindle 30 into the first axial position range 50, in which further axial motion is stopped again by the detent mechanism 48. With this first axial movement 60 of the spindle nut 31, the spindle nut 31 is again meshed by means of the toothing 56 with one of two gear wheels 33, 34 at a time, which are operatively connected to the selector shaft 3. The shifting motion 12 is thus performed by means of the axial movement of the spindle nut 31.

    [0057] The specification description of DE 10 2013 207 871 is referenced in its entirety.

    [0058] The gear wheel pairings, which transmit the motion of the motor 41 to the spindle 30, to the free-wheel mechanism 51, to the selector pot 53 and to the shaft gear 35 and thereby bring about the selecting motion 11 and the shifting motion 12 of the selector shaft 3, are referred to as the connecting device 18.

    [0059] FIG. 2 shows a detail of FIG. 1 in a view rotated by 90; here the spindle nut 31 is meshed with the second gear wheel 34 through the toothing 56, so that an axial movement 60 (see FIG. 1) causes a rotation of the second gear wheel 34 and with it a rotation of the shaft gear 35, and thus a shifting motion 12 of the selector shaft 3. When the selector shaft 3 rotates, the gearshift lever 47 positioned on the selector shaft 3 performs a shifting motion 12, whereby a motor vehicle transmission device 2 is operated and a gear is shifted accordingly.

    [0060] FIG. 3 shows an H-shaped shifting diagram as an abstraction of the selecting motion 11 and the shifting motion 12. Here the gearshift lever 47 is positioned before the reverse gear or the fourth gear, and can perform a shifting motion 12 when a corresponding selecting motion 11 is made.

    [0061] FIG. 4 shows a selector shaft 3 with a gate 4 positioned on it, a gearshift lever 47 and gearshift rails 57 of a motor vehicle transmission device 2. The gearshift lever 47 has a selector finger 62 and a plurality of throw-out cams 61. The throw-out cams 61 of the gearshift lever 47 are designed so that they can interact in the nature of an active interlock with the gearshift rails 57 of the motor vehicle transmission device 2 shown here. On the operation and the construction of such an active interlock, you are referred to the unpublished DE 10 2013 203 284 of the applicant, which is hereby likewise referenced in its entirety.

    [0062] In the depiction shown here, the selector finger 62 is positioned directly before a gearshift rail 57, so that when the selector shaft 3 makes a shifting motion 12 a gear may be engaged. This position of the selector finger 62 before the gearshift rail 57 is set by the gate 4. To this end, the gate 4 has a second gate part 6 with lands 9 and slots 8, the second gate part 6 being positioned around the selector shaft 3 and coaxial to the selector shaft 3. Here, a first gate part 5 with an element 10 extends around the second gate part 6 in such a way that the element 10 can reach in from outside into the slot 8 between lands 9. This makes it possible when the selector shaft 3 makes a shifting motion 12 for the second gate part 6, which is firmly connected to the selector shaft 3, to be turned in a circumferential direction 19, 20 relative to the first gate part 5, so that the element 10 dips into the slot 8 in the course of a shifting motion 12.

    [0063] FIG. 5 shows the arrangement according to FIG. 4, while here the selector finger 62 is positioned before two adjacent gearshift rails 57 in such a way that in the event of a shifting motion 12 two gears would be engaged simultaneously. This shifting motion 12 is prevented by the gate 4 however, since the element 10 bumps against the land 9 when there is a shifting motion 12.

    [0064] FIG. 6 shows a second gate part 6 according to a first variant embodiment. The second gate part 6 has slots 8 and lands 9 alternating in a direction 7, 22. On an internal circumferential surface 24, the second gate part 6 has a first profile toothing 23. On the first profile toothing 23, a coding tooth 27 is provided, which allows only one installation position of the second gate part 6 and the selector shaft 3 (not shown here) relative to one another. Furthermore, a marking 29 is positioned on the second gate part 6 in such a way that the installation position 28 of the second gate part 6 relative to the selector shaft 3 is recognizable. This simplifies assembly of the second gate part 6 and prevents incorrect positioning on the selector shaft 3. The second gate part 6 has two tracks 21 located opposite each other, and slots 9 and lands 8 on both sides 26 of each track 21. This makes a shifting motion 12 possible in a first circumferential direction 19 and in a second circumferential direction 20.

    [0065] It can be seen here that in the case of the second gate part 6 shown, another track 21 is positioned opposite. This would enable the second gate part 6 to be installed (for example if there are two coding teeth 27) also rotated by 180 and also possibly tilted by 180.

    [0066] FIG. 7 shows the interaction of the second gate part 6 according to FIG. 6 and a first gate part 5. The first gate part 5 is fixed with respect to the housing relative to the movable selector shaft 3. The second gate part 6 is positioned on the selector shaft 3 and is axially movable together with the selector shaft 3 for selecting gears, and rotationally movable for shifting gears. The first gate part 5 has elements 10, one of which at a time can interact with one of the lands 9 and is movable into one of the slots 8. In a selecting motion 11, the elements 10 are positioned in the track 21 and can be guided past the lands 8 and slots 9. In a shifting motion 12, the elements 10 can be moved into one of the slots 9. The slots 8 prevent a shifting motion 12 from being carried out if the selector finger 62 is not correctly positioned in the motor vehicle transmission device 2. To this end, the position of the motor vehicle transmission device 2 relative to the first gate part 5 and relative to the second gate part 6 and the selector shaft 3 must be set exactly.

    [0067] The gate 4 now has the following functions, which are depicted schematically in FIGS. 8-11. On the one hand, the gate 4 prevents a selecting motion 11 while a gear is engaged (see e.g. FIG. 9). Moreover, the gate 4 prevents two gears from being able to be engaged at the same time (see e.g. FIG. 11). Furthermore, the gate 4 also serves as a torque support, for example when returning from a slot 8 into the track 21. Without gate 4 there would be no definition on the return path of whether the selector finger 62 is to perform a selecting motion 11 or a shifting motion 12. Blockages (when elements 10 strike lands 9) can be detected by a control system 38 by means of sensors, so that a present actual position 39 of the selector shaft 3 and thus of the second gate part 6 is determinable. Starting from the ascertained present actual position 39, target positions 40 (selecting motion 11, shifting motion 12) can be moved to precisely.

    [0068] Furthermore, the gate 4 makes it possible for greater production tolerances of the elements involved in the shifting motion, such as the selector finger, to be permissible; even larger mis-positionings of these elements relative to each other can be compensated for, thus reducing the number of unsuccessful attempts at shifting procedures, while at the same time a tightening of the connecting device 18 is avoided. That is, particularly with the single-motor transmission actuator 1, it is important to avoid a movement of the selector shaft 3 being provoked or forced which acts in the blocked direction of rotation of the free-wheel mechanism 51.

    [0069] FIG. 8 shows the track 21 and slots 8 and lands 9 of a second curtain part 6, as well as an element 10 of a first curtain part 5. This interaction of element 10 and slots 8 corresponds to the abstract shifting diagram according to FIG. 3. Here, the element 10 of the first gate part 5 is located in the slot 8 of the second gate part 6. This means that a gear is engaged by a shifting motion 12 of the selector finger 62 in the motor vehicle transmission device 2. The element 10 has an end wall 16 and an insertion chamfer 13 between the end wall 16 and the first wall 15. The first wall 15 points in the prescribed direction 58 of a selecting motion 11.

    [0070] FIG. 9 shows the gate 4 in a different arrangement of the first gate part 5 and second gate part 6 relative to one another. Here, the element 10 contacts the land 8 in the slot 9. In this way, an actual present position 39 of the land 8 and/or of the element 10 in direction 7, 22 along the selection motion 11 can be determined. This actual present position 39 may be matched with a target position 40 in the control system 38, so that wear of the transmission actuator 1 can also be determined. In the selecting motion 11, the second gate part 6 is moved in the prescribed direction 58 relative to the fixed first gate part 5.

    [0071] FIG. 10 shows the complete selecting motion 11 and shifting motion 12 of the gate 4 with movable second gate part 6 and fixed first gate part 5. The second gate part 6 can be positioned so that it is axially and rotationally movable relative to the gate part 5, the second gate part 6 here having slots 8 and lands 9 alternating in a direction 7, 22. Furthermore, the second gate part has slots 9 and lands 8 on both sides 26 of the track 21, so that starting from a selecting motion 11 in the slot 21 in a prescribed direction 58 a shifting motion 12 can only be carried out in one circumferential direction 19, 20 at a time.

    [0072] The slots 9 and lands 8 are now moved in the prescribed direction 58 past the element 10 under the selecting motion 11, while under a shifting motion 12 the second gate part 6 is swiveled in a circumferential direction 19, 20 relative to the element 10 in such a way that the element 10 can be moved into one of the slots 9. If a shifting motion 12 occurs in the depicted position of the element 10, then by means of the insertion chamfer 13 the right element 10 can push the second gate part 6 further in the prescribed direction 58 of the selecting motion 11, so that the slot 8 is reached and the element 10 can be pushed into the slot 8. Thereby, the selector finger 62 is also positioned correctly, so that mis-positionings of the selector finger 62 and/or of the slot 8 are also compensated for and thus the available window for shifting the gear has been enlarged. But if a shifting motion 12 is carried out in circumferential direction 20, the left element 10 interacts with the slots 9 and lands 8 of the other side 26 of the track 21.

    [0073] FIG. 11 shows the depiction according to FIG. 8, with an erroneous shifting motion 12 being stopped here. In the arrangement shown here of first gate part 5 with element 10 and second gate part 6 with slots 9 and lands 8, a shifting motion 12 is not possible, since the end face 16 of the element 10 collides with the land 8. Since there is no insertion chamfer 13 present here, the second gate part 6 cannot be moved contrary to the prescribed direction 58, so that a shifting motion 12 and at the same time a tightening of the connecting device 18 is prevented here.

    [0074] FIG. 12 shows a first gate part 5 with two elements 10 that can be arranged jointly in a track 21 of a second gate part 6 (for example in accordance with FIGS. 4-11). The elements 10 each have first walls 16 in the prescribed direction 58 of the selecting motion 11 and second walls 17 pointing in the direction contrary to the prescribed direction 58. Between second walls 17 and the end walls 16 in each case right-angled transitions 14 are provided, there being insertion chamfers 13 provided in each case between the end walls 16 and the first wall 15. By means of the insertion chamfers 13, the second gate part 6 can be pushed further in the prescribed direction 58 of the selecting motion 11, from which a selecting motion 12 can be carried out in only one circumferential direction 19, 20 at a time.

    [0075] The insertion chamfer 13 is thus at an angle 63 of less than 90 degrees relative to the prescribed direction 58, in particular between 50 and 70 degrees. At the same time, the insertion chamfer 13 has a length 65 in the direction of the shifting motion 12 (here circumferential direction 20) such that the second gate part 6 is movable further in the prescribed direction 58 by a distance 64 beyond the length 65 of the insertion chamfer 13. These statements are transferable correspondingly to insertion chamfers 13 on the second gate part 6 (or to the gate for 4 according to the second variant embodiment in FIGS. 14 and 15).

    [0076] FIG. 13 shows a single-motor transmission actuator from the side in a sectional view. As already described in reference to FIG. 1, a spindle 30 is driven by means of a motor 41 not shown here, and by means of the spindle nut 31 and a third gear wheel 49 a selector wheel 52 positioned on the free-wheel mechanism 51. The selector wheel 52 is provided to turn the selector pot 53. Trajectories 54 run in the selector pot 53 which interact with guide pins 55 so that when the selector pot 53 is turned the selector shaft 3, which is operationally connected to it by means of the guide pins 55, performs a selecting motion 11. Positioned on the selector shaft 3 is a gearshift lever 47 with selector finger 62 and throw-out cams 61. By means of the spindle 30, the threaded spindle 31 is able to perform an axial motion 60, so that the gear wheels 33, 34 can be turned by means of the spindle nut 31 designed as toothed rack 32. The gear wheels 33, 34 are operationally connected to the shaft gear 35, which is connected non-rotatingly to the selector shaft 3. The shifting motion 12 is thus performed by means of the axial movement 60 of the spindle nut 31. The first gate part 5 is provided, in this case, by means of a pot which is positioned radially outside in reference to the selector shaft 3, while the second gate part 6 is an element of the selector shaft 3. In particular, the second gate part 6 may also be produced from the selector shaft 3 itself by a reshaping procedure or milling of the selector shaft 3.

    [0077] FIG. 14 shows a detail of a single-motor transmission actuator 1 in a perspective view with a second variant embodiment of a gate 4. We refer to the description of FIG. 1. Like reference labels designate like objects. Here the transmission actuator 1 includes a spindle 30 with a spindle nut 31, where the spindle nut 31 forms a toothed rack 32 and is operatively connected to a shaft gear 35 through one of two gear wheels 33, 34 at a time, the shaft gear 35 being firmly connected to the selector shaft 3.

    [0078] Here, the spindle nut 31 forms the second gate part 6. Slots 9 and webs 8 run parallel to a spindle axis 36, and the element 10 of the first gate part 5 is formed by at least one pin 37 (here by two pins which are positioned parallel to one another and on opposite sides of the spindle axis 36).

    [0079] FIG. 15 shows a detail of the single-motor transmission actuator according to FIG. 14 in a view along the spindle axis 36. In a selecting motion 11, the second gate part 6 is rotated in the prescribed direction 58 relative to the fixed pins 37 of the first gate part 5. In a shifting motion 12, the spindle nut performs an axial movement 60 along the spindle axis 36. When the positioning is appropriate, the pins 37 reach into the slots 9 of the second gate part 6 and thus enable the shifting motion 12. Here too, an insertion chamfer 13 in the transition 14 from the end face 16 to the first wall 15 enables the second gate part 6 to be shifted in the prescribed direction 58 when pin 37 and land 8 collide. A shift in the opposite direction is prevented by the right-angled transition 14 between end face 16 and second wall 15.

    [0080] Independent of the configuration described above, it is of course possible to reverse the operating principle of the described transmission actuators. For a person skilled in the art, it is easily possible here to attach a gate rail in a fixed location which corresponds to the gate 4 described above, but is constructed essentially complementarily to that gate 4, i.e., among other things hollow inside. This gate rail would then be fixed with respect to a housing and would provide slots 8 for elements 10 positioned non-rotatingly on the selector shaft 3. The first gate part would then be constructed correspondingly complementarily to the first gate part 6 and would be connected to the selector shaft 3.

    REFERENCE LABELS

    [0081] 1 transmission actuator [0082] 2 motor vehicle transmission device [0083] 3 selector shaft [0084] 4 gate [0085] 5 first gate part [0086] 6 second gate part [0087] 7 first direction [0088] 8 slot [0089] 9 land [0090] 10 element [0091] 11 selecting motion [0092] 12 shifting motion [0093] 13 insertion chamfer [0094] 14 transition [0095] 15 first wall [0096] 16 end face [0097] 17 second wall [0098] 18 connecting device [0099] 19 first circumferential direction [0100] 20 second circumferential direction [0101] 21 track [0102] 22 second direction [0103] 23 first profile toothing [0104] 24 internal circumferential surface [0105] 25 slot [0106] 26 side [0107] 27 coding tooth [0108] 28 installation position [0109] 29 marking [0110] 30 spindle [0111] 31 spindle nut [0112] 32 toothed rack [0113] 33 first gear wheel [0114] 34 second gear wheel [0115] 35 shaft gear [0116] 36 spindle axis [0117] 37 pin [0118] 38 control system [0119] 39 present actual position [0120] 40 target position [0121] 41 motor [0122] 42 spur gearing [0123] 43 motor spindle [0124] 44 first rotation direction [0125] 45 second rotation direction [0126] 46 ring gear toothing [0127] 47 gearshift lever [0128] 48 detent mechanism [0129] 49 third gear wheel [0130] 50 first axial position range [0131] 51 free-wheel mechanism [0132] 52 selector wheel [0133] 53 selector pot [0134] 54 trajectory [0135] 55 guide pin [0136] 56 toothing [0137] 57 gearshift rail [0138] 58 prescribed direction [0139] 59 external circumferential surface [0140] 60 axial movement [0141] 61 throw-out cams [0142] 62 selector finger [0143] 63 angle [0144] 64 distance [0145] 65 length