Patent Publication Number: US-2010107798-A1

Title: Shifting device for an automatic transmission

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This U.S. application claims priority to German Application DE 10 2008 022 561.4 filed on Apr. 30, 2008, which is incorporated by reference herein in its entirety. 
     FIELD OF THE INVENTION 
     The present invention pertains to a shifting device for an automatic transmission of a motor vehicle. 
     BACKGROUND OF THE INVENTION 
     A shifting device for an automatic transmission of a motor vehicle which comprises a gear-shift lever, which can be moved in an automatic shift track to select gear-shift positions, is known from DE 100 57 299 A1. This automatic shift track can comprise, for example, gear-shift positions for parking, reverse, neutral, and drive. The known shifting device also comprises a locking mechanism, which can be switched at least between a locked state and a released state. It also comprises a release button for changing the state of the locking mechanism. In the locked state, the locking mechanism blocks the movement of the gear-shift lever at least into the park and reverse positions and at least out of the park position. In the released state, the locking mechanism allows the gear-shift lever to be moved at least between Park, Reverse, Neutral, and Drive. 
     The known shifting device also comprises a manual shift track, in which the gear-shift lever can be moved between a middle position, an upshift position, and a downshift position. A transverse shift track is also provided so that the gear-shift lever can be switched between the automatic shift track and the manual shift track. 
     DE 100 21 461 C1 shows a shifting device with a blocking mechanism for blocking the gear-shift lever in Park and Neutral. For this purpose, the blocking mechanism comprises two separate locking elements, which cooperate with a common blocking gate. One of the locking elements engages in the blocking gate to block the park position, whereas the other locking element engages in the blocking gate to block the neutral position. 
     DE 197 28 064 B4 shows another shifting device with a blocking mechanism, by means of which the gear-shift lever can be blocked in Park. For this purpose, a locking element is provided, which can engage in an arresting gate, which comprises gate sections assigned to the gear-shift positions of the gear-shift lever. A locking element connected to the gear-shift lever works together with the arresting gate. When the gear-shift lever is in Park, the locking element on the gear-shift lever side engages in the associated section of the gate. To block the park position, the locking element of the blocking mechanism now also engages in the arresting gate in such a way that the locking element on the gear-shift lever side can no longer be moved out of the section of the gate assigned to Park. 
     A shifting device for a tractor by means of which two gear ratios of a gearbox can be selected is known from U.S. Pat. No. 4,398,433. At the bottom of a shifting knob, the gear-shift lever comprises two short stops and one long stop, which project into a gate. The gate comprises a first gate section for the first shifting stage, a second gate section for the second shifting stage, and a central, third gate section assigned to a neutral position, located between the two first-mentioned gate sections. The short stops make it possible to block the gear-shift lever in the gear-shift positions assigned to the two gear ratios and in the position assigned to neutral. The long stop realizes end stops for the adjusting movement of the gear-shift lever in the first gate section and also in the second gate section. By pulling the gear-shift lever out, the short stops come free of the gate and make it possible, for example, to move the gear-shift lever out of the gear-shift position assigned to one of the two gear ratios. It can then be pushed into the neutral position. The long stop guarantees here that, with the help of an end stop, the neutral position will be found. By pulling the gear-shift lever out even farther, the long stop will also come free of the gate, so that it is possible to rotate the shifting knob 180° around its longitudinal axis. As a result, the long stop can be moved over from the first gate section to the second gate section. After that, the gear-shift lever can be moved in the second gate section, which is assigned to the second gear ratio. 
     DE 101 46 776 B4 describes a shifting device in which the gear-shift lever can be moved to various positions in a two-dimensional shift gate. To block the gear-shift lever in Park and Reverse, locking elements are provided, which engage directly in the shift gate and cooperate directly with the gear-shift lever. 
     WO 2005/025916 A1 describes a shifting device with a blocking mechanism which comprises a latching cone, which engages in a recess assigned to the park position, this recess being formed in a segment disk, which moves concomitantly with the gear-shift lever. The latching lever has a latching projection and two parallel side pieces. 
     SUMMARY OF THE INVENTION 
     The present invention deals with the problem of providing, for a shifting device of the type indicated above, an improved or at least a different embodiment, which is characterized in particular in that it realizes improved shifting convenience or actuation convenience and/or that it has increased stability and/or that it comprises a higher level of failure safety. 
     The invention relates to the general idea of equipping the shifting device with a latching mechanism, which comprises latching positions assigned to the gear-shift positions. The latching mechanism comprises at least one latching element, which cooperates with a latching gate, which comprises several gate sections. The latching gate in question is designed so that the gate sections form stable latching positions for the latching element, these positions being assigned to the gear-shift positions. The latching element in question is pretensioned by the force of a spring into the associated latching position, and the latching element can be moved out of that position again against the force of the spring. The latching mechanism gives the user a significant amount of haptic feedback, as a result of which it is very easy for him to recognize when the gear-shift lever has reached the predetermined gear-shift position. The inventive proposal of assigning stable latching positions to the gear-shift positions is especially advantageous. It has the result that, to accomplish the shifting operation, i.e., to move the gear-shift lever in the automatic shift track, the user must exert a certain amount of force to move the gear-shift lever out of its current position. Simultaneously, the force of a spring supports the movement of the gear-shift lever toward the discovery of the next gear-shift position. Through this design, the gear-shift lever can be shifted comparatively easily in an intuitive manner, without eye contact, which increases the convenience with which the shifting device can be operated 
     Especially advantageous is an embodiment in which the latching mechanism comprises two latching elements, which cooperate simultaneously with the associated latching gate. As a result, it is possible to realize comparatively powerful spring forces, which improve the centering of the gear-shift lever in the latching position in question. In addition, the load exerted on the individual latching elements and/or on the associated latching gate can also be reduced, which prolongs the service life of the shifting device. The redundant design also leads to an increased degree of failure safety. 
     In an advantageous elaboration, one the two latching elements can be arranged on one side of the gear-shift lever, the other latching element on the other side. As a result of this design, the spring forces which act on the gear-shift lever when the lever is shifted or moved can be transmitted symmetrically to the gear-shift lever, which avoids in particular the introduction of torque acting around the longitudinal axis of the gear-shift lever. As a result, the load exerted on a bearing of the gear-shift lever can be considerably reduced. Thus this measure also leads to an increase in the service life of the shifting device. 
     The shifting device presented here is especially suitable for use in conjunction with a dual-clutch automatic transmission. A dual-clutch automatic transmission of this type makes it possible to shift extremely quickly from one gear to the next. The proposed shifting device offers the possibility of exploiting this property of the dual-clutch transmission in an especially effective manner. In particular, dynamic shifting operations can be realized in the automatic shift track when maneuvering or when the automatic transmission is actuated in the manual shift track. Dynamic shifting operations or dynamic actuating operations which are possible with such a dual-clutch transmission require an especially sturdy shifting device, which can be subjected to high loads. The proposed shifting device has the desired high degree of sturdiness and operating reliability. The dual-clutch automatic transmission can be designed in an especially advantageous manner as a seven-gear automatic transmission, which comprises seven forward gears. In addition, the shifting device presented here is especially suitable for use in sports vehicles or in a vehicles with a rear-mounted engine. Dynamic shifting operations are frequently desired precisely in the case of sports vehicles, especially those with a rear-mounted engine. As a result of higher degree of actuation convenience and its increased reliability, the sturdy shifting device presented here makes such dynamic shifting operations possible. 
     Other important features and advantages of the invention can be derived from the drawings, and from the associated description of the figures on the basis of the drawings. 
     It should be obvious that the features cited above and to be explained below are applicable not only in the combinations specifically stated but also in other combinations or even alone without leaving the scope of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred exemplary embodiments of the invention are illustrated in the drawings and are explained in greater detail in the following description, where the same, similar, or functionally equivalent components are designated by the same reference numbers. 
       In schematic fashion, 
         FIG. 1  shows a perspective view of a selector device, 
         FIG. 2  shows a schematic top view of a shifting gate, and 
         FIGS. 3-9  show perspective, partially cut-away views of the shifting device from different angles and in different cross sections. 
     
    
    
     BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG. 1 , an inventive shifting device  1 , which is used in conjunction with an automatic transmission of a motor vehicle, comprises a gear-shift lever  2 , which comprises a hand grip  3 . A release button  4 , which, in this example, is integrated into the hand grip  3 , is also provided on the gear-shift lever  2 . The gear-shift lever  2  can be moved in a shift gate  5 , a simplified view of which is shown in  FIG. 2 . The shift gate  5  comprises an automatic shift track  6 , a manual shift track  7 , and a transverse track  8  The gear-shift lever  2  can be moved in the automatic shift track  6  and in the manual shift track  7  to select gear-shift positions  9 . For example, the automatic shift track  6  comprises the following gear-gear-shift positions: Park P, Reverse R, Neutral N, and Drive D. In contrast, the manual shift track  7  comprises, for example, a Middle M position, an upshift position +, and a downshift position −. The transverse shift track  8  allows the gear-shift lever  2  to be moved between the automatic shift track  6  and the manual shift track  7 . 
     The shift gate  5  shown in  FIG. 2  therefore has one-dimensional shift tracks  6 ,  7 ,  8 , in which the gear-shift lever  2  can be moved only in the longitudinal direction in the automatic shift track  6  and in the manual shift track  7  and only in the transverse direction in the transverse shift track  8 . 
     To realize the shift gate  5 , the gear-shift lever  2  according to  FIG. 1  is supported on a bearing block  10  or a shift block  10  or a selector block  10 . An actuating cable  11 , which leads to the automatic transmission (not shown), extends out from the bearing block  10  and can be actuated on the shift block  10  by the gear-shift lever  2 . The automatic transmission is preferably a dual-clutch automatic transmission. In particular, it can be a seven-gear automatic transmission. The motor vehicle in which the shifting device  1  shown here is preferably used is a sports vehicle and/or a vehicle with a rear-mounted engine. 
     The shift block  10  has a housing  12 , which is at least partially omitted in  FIGS. 3-9  so that the internal structure of the shifting device  1  can be explained in greater detail. 
     The shifting device  1  comprises a locking mechanism  13 , at least part of which can be seen in, for example,  FIGS. 3 and 4 . This locking mechanism  13  can be switched at least between a locked state and a released state. The previously mentioned release button  4  cooperates with the locking mechanism  13 . In particular, the release button  4  forms a component of the locking mechanism  13 . By means of the release button  4 , the state of the locking mechanism  13  can be changed. In the locked state, the locking mechanism  13  prevents the gear-shift lever  2  from being moved into the Park P and Reverse R positions. In addition, when in the locked state, it blocks the movement of the gear-shift lever  2  out of the Park P position. The locking mechanism  13 , when in its locked state, can basically allow the movement of the gear-shift lever  2  out of the Reverse R, Neutral N, and Drive D positions. When in the locked state, it can also allow a changeover between the shift tracks  6 ,  7 . When in the locked state, it can also be moved freely in the manual shift track  7  between the Middle M position, the upshift position +, and the downshift position −. In its released state, the locking mechanism  2  also makes it possible for the gear-shift lever  2  to be moved into and out of the Park P position. Thus the gear-shift lever  2 , when in the released state in the automatic shift track  6 , can be moved freely between the individual gear-shift positions of the automatic shift track  6 , i.e., between the Park P, Reverse R, Neutral N, and Drive D positions. 
     The locking mechanism  13  is also designed so that can be converted into a partially released state. In this partially released state, the gear-shift lever  2  can be moved not only into the possible gear-shift positions allowed by the locked state but also into and out of the Reverse R position. In contrast to the released state, the gear-shift lever  2 , when in this partially released state, cannot be moved into or out of the Park P position. This means that the movement of the gear-shift lever  2  in the automatic shift track  6  into the Park P position and out of that position is blocked when the partially released state is active. The partially released state therefore makes it possible for the driver to shift between the Reverse R and Drive D positions without the danger that he could shift into the Park P position by mistake; in particular, this partially released state makes it possible for the driver to accomplish this shifting without the need for visual confirmation that he is shifting correctly. This partially released state is therefore especially suitable for maneuvering operations of the vehicle. 
     To realize this partially released state, the release button  4  has two actuation positions. In a first actuation position, the locking mechanism  13  is converted into the partially released state. In a second actuation position, the locking mechanism  13  is converted into the released state. When the release button  4  is not actuated, the locking mechanism  13  is converted into the released state. It is especially advantageous here that the different states of the locking mechanism  13  can be set or changed by the use of only a single release button  4 . 
     It is advisable for the release button  4  to be designed so that it realizes the two actuation positions in a manner which can be differentiated haptically, specifically on the basis of different actuating pressures and/or different actuation distances. Preferred here is an embodiment in which different actuating pressures lead to different actuation distances. For example, the release button  4  is preferably designed as a rocker button, which is supported so that it can be pivoted around a pivot axis  14  on the gear-shift lever  2  or grip  3 . In the present example, the release button  4  is arranged on the grip  3  so that it is accessible from above and so that it can be actuated by the thumb of the hand grasping the hand grip  3  in an ergonomically favorable manner. To actuate the release button  4 , the user uses his thumb to press the actuating button  4  downward. So that the different actuation states can be differentiated from each other, the actuation distance for setting the second actuation position is longer than the actuation distance for setting the first actuation position. In addition or alternatively, the actuating pressure for setting the second actuation position can also be greater than the actuating pressure for setting the first actuating position. 
     An ergonomically especially favorable actuation, which can be realized in an especially intuitive manner, can be achieved if the release button  4  can be moved out of its unactuated, resting position assigned to the locked state by pressing it down against an initial resistance. Said initial resistance forms a pressure stage, and when this is overcome, the release button  4  snaps into the first actuation position and then can be held there by pressing against a holding resistance. Said holding resistance is weaker than the initial resistance required to overcome the pressure stage. In other words, to reach the first actuation position, the user must exert a comparatively large amount of force to overcome the initial resistance and thus to actuate the release button  4 . Then, to maintain the first actuation position, the user need exert only a comparatively weak holding force to compensate for the holding resistance. 
     So that the release button  4  can now be switched from its first actuation position into the second actuation position, it can be provided according to an effective design that, for this purpose, pressure must again be exerted against an actuation resistance which is greater than the holding resistance. In other words, to move from the first actuation position into the second actuation position, the user must press the release button  4  down harder than is necessary just to hold the release button  4  in the first actuation position. This configuration can be experienced and learned intuitively. 
     It is advisable for realizing the second actuation position to provide a stop, which limits the movement or pivot path of the release button  4 . Optionally, the actuation resistance which must be overcome to reach the second actuation position can be at least as strong as the initial resistance which must be overcome to reach the first actuation position. As a result, the two actuation positions differ not only on the basis of the different actuation distances but also on the basis of the different actuating pressures or actuating forces. 
     So that the kinematics for the release button  2  presented here can be realized, the gear-shift lever  2  comprises a tubular body  15 , in which a pushrod  16 , visible in  FIG. 3 , is supported with freedom to move up and down. A drive connection is established between the release button  4  and the pushrod  16  (not shown), so that actuation of the release button  4  generates a corresponding stroke of the pushrod  16 . A slide  17 , which can also move up and down, is also arranged on the tubular body  15 . This slide coaxially surrounds the tubular body  15 . A drive connection is established between the pushrod  16  and this slide  17 , so that a stroke of the pushrod  16  generates a stroke of the slide  17 . For example, the connection between the pushrod  16  and the slide  17  can be established by means of at least one pin  18 , which is permanently attached to the pushrod  16  and which passes through a slot  19 , formed in the tubular body  15 , and which positively engages in a corresponding opening in the slide  17 . The slot  19  is oriented in the direction in which the push rod  15  and the slide  17  move, that is, in the longitudinal direction of the tubular body  15 . Between the slide  17  and the tubular body  15  there is also a latch  20 , which serves to realize the initial resistance or pressure stage. For this purpose, the latch  20  comprises, for example, an elastic latching element  21 , which is permanently connected to the slide  17 . The latching element  21  comprises a latching projection  22 , which engages in a latching contour  23 . Said latching contour  23  is formed on the tubular body  15 . The latching contour  23  comprises a latching edge  24 , on which the latching projection  22  rests in the downward-oriented actuating direction of the release button  4 . When the release button  4  is actuated, the latching element  21  is displaced outward by the sliding of the latching projection  22  along the latching contour  23 , namely, displaced against the resistance of the latching element  21 . As soon as the latching projection  23  reaches the other side of the latching edge  24 , the initial resistance realized by means of the latch  20  decreases sharply. The latching projection  23  now engages in a second latching contour  25 . The release button  4  is now in its first actuation position. The second latching contour  25  is flatter in design than the previously mentioned first latching contour  23 . The pushrod  16  is advisably supported in the tubular body  15  by means of a compression spring (not shown), which makes an essential contribution to the actuation resistance of the release button  4 . Until the pressure stage realized by means of the latch  20  is overcome, the actuation resistance of the release button  4  is formed by the restoring force of the previously mentioned spring and by the restoring force of the latching element  21 . After the pressure stage is overcome, only the restoring force of the spring is present initially, because the latching projection  22  of the latching element  21  is engaged in the second latching contour  25 . Only when the release button  4  is moved even farther can the latching element  21  be displaced outward again, so that it once again can contribute to the actuation resistance. 
     The length of the slot  19  can be used, for example, to realize end stops to define the second actuation position of the release button  4  and also to define a rest position for the release button  4 , which is present when the release button  4  is unactuated. The restoring force of the previously mentioned spring is strong enough in the first actuation position and necessarily also in the second actuation position to move the pushrod  16  along with the slide  17  automatically back to, and to pretension the release button  4  in, its rest position. In particular, the restoring force is thus sufficiently strong that the latching element  21  can travel past the latching edge  24 . 
     The locking mechanism  13  comprises at least one blocking element  26 , which is arranged on the gear-shift lever  2  with the freedom to move up and down, a drive connection being established between the release button  4  and this blocking element. The release button  4  and said blocking element  13  cooperate in such a way that actuation of the release button  4  generates a stroke of the blocking element  26 . In the present example, the blocking element  26  is attached to the slide  17 , which is connected to the release button  4  by the pushrod  16 . As shown in  FIG. 4 , the locking mechanism  13  also comprises at least one arresting gate  27 , which cooperates with the associated blocking element  26 . The arresting gate  27  comprises several gate sections. In the present example, four gate sections are provided, namely, a first gate section  28 , a second gate section  29 , a third gate section  30 , and a fourth gate section  31 . The first gate section  28  is assigned to the two gear-shift positions Neutral N and Drive D. the second gate section  29  is assigned to the Reverse R position. The third gate section is not assigned to a gear-shift position and serves only to switch the gear-shift lever  2  over between the Reverse R and Park P positions. The fourth gate section  31  is accordingly assigned to the Park P position. The first gate section  28  is separated from the second gate section  29  by a first step  32 . This first step  32  can be overcome by bringing the blocking element  26  into its first stroke position, which is assigned to the first actuation position of the release button  4 . The second gate section  29  is separated from the third gate section  30  by a second step  33 . This second step  33  can be overcome by bringing the blocking element  26  into its second stroke position, which is assigned to the second actuation position of the release button  4 . In addition, the fourth gate section  31  is separated from the third gate section  30  by a third step  34 . The third step  34  can also be overcome by bringing the blocking element  26  into its second stroke position, which is assigned to the second actuation position of the release button  4 . The locking mechanism  13  works as follows. 
     In  FIG. 4 , the locking mechanism  13  is in its locked state. In addition, the Park P position has been selected. The release button  4  is unactuated. So that it is possible now to pass from the fourth gate section  31  to the adjacent gate section  30 , the release button  4  must be moved into its second actuation position, as a result of which the locking mechanism  13  assumes its released state. As a result, the blocking element  26  arrives in its second stroke position, which is sufficient to overcome the third step  34 . The gear-shift lever  2  can now be pivoted, namely, around a transverse axis  35 . As a result, the blocking element  26  arrives in the third gate section  30 . From here, the gear-shift lever  2  can be moved as desired either into the Reverse R position, i.e., into the second gate section  29 , or back again into the Park P position, i.e., back into the fourth gate section  31 . The release button  4  does not have to be actuated again to accomplish this. When moved into the second gate section  29 , the blocking element  26  springs back into its first stroke position, the release button  4  remaining unactuated at this point. Without actuation of the release button  4 , the gear-shift lever  2  can no longer be moved back into the Park P position, because for this purpose it is necessary to overcome the second step  33 . In contrast, without actuation of the release button  4 , it is possible to shift into the Neutral N position and the Drive D position. As soon as the blocking element  26  engages in the first gate section  28 , it springs back into its starting position. Without actuation of the release button  4 , the gear-shift lever  2  can now be shifted only between the Neutral N position and the Drive D position. So that it can move back into the Reverse R position again, the step  32  must first be overcome. For this purpose, the release button  4  must be moved into its first actuation position to bring about the partial release of the locking mechanism  13 . Said partially released state, however, is not sufficient to overcome the second step  33  as well, which means that, in the partially released state, the gear-shift lever  2  cannot be moved into the Park P position. Only by actuating the release button  4  in such a way that the release button  4  is moved into its second actuation position can the blocking element  26  overcome the second step  33 . The locking mechanism  13  is now completely released, and the gear-shift lever  2  can be moved directly into the Park P position and back out of it again. 
     The locking mechanism  13  therefore serves to block switching movements of the gear-shift lever  2  into at least one gear-shift position  9  and/or out of at least one gear-shift position  9 . Simultaneously, the release button  4  on the gear-shift lever  2  serves to release the blocking action of the locking mechanism  13 . As shown in  FIG. 5 , two blocking elements  26  are arranged simultaneously on the gear-shift lever  2  with freedom to move up and down. The two blocking elements  26  are arranged in redundant fashion. The two blocking elements  26  are attached to the slide  17 ; the pushrod  16  establishes a drive connection between the slide and the release button  4 . Accordingly, the two blocking elements  26  can be moved up and down synchronously by actuation of the release button  4 . Each of the two blocking elements  26  interacts with an arresting gate  27 . In the example, two arresting gates  27  are provided for this purpose, wherein each of the two blocking elements  26  cooperates with one of these arresting gates  27 . The embodiment shown here, in which the two arresting gates  27  are formed in a common component  35 , is especially advisable. The two arresting gates  27  are arranged in such a way that they merge continuously with each other. This is especially evident in the middle area, in which the first gate section  28  of the arresting gate  27  shown on the right merges seamlessly or continuously with the fourth gate section  31  of the arresting gate  27  shown on the left. The two blocking elements  26  are thus advisably arranged on the same side of the gear-shift lever  2 . As a result, the redundancy can be realized in an especially compact manner. 
     The shifting device  1  is also equipped with a blocking mechanism  36 , which can be seen especially clearly in  FIG. 5 . The blocking mechanism  36  serves to block the gear-shift lever  2  in the Park P position. For this purpose, the blocking mechanism  36  comprises two blocking elements  37 , which are arranged in redundant fashion. Each blocking element  27  cooperates with a blocking gate  38 . The blocking gate  38  comprises a gate section  39 , which is assigned to the Park P position. When the gear-shift lever  2  is in the Park P position, the blocking element  27  engages in this gate section  39 . In the present example, the blocking element  37  has for this purpose an angled terminal section  40 , which cooperates with the associated gate  38 . For this purpose, the terminal section  40  engages positively in the blocking gate  38 , i.e., in the gate section  39 . 
     The two blocking elements  37  are formed on a common blocking lever  41 . This blocking lever  41  is supported pivotably around a pivot axis  42  and comprises an actuating arm  43 , a drive connection being established between this arm and an actuator  44 . The blocking lever  41  in the embodiment shown here also comprises an emergency actuation lever  45 , which, in the event that the actuator  44  fails, can be actuated manually to move the blocking elements  37  out of their blocking position. 
     The blocking lever  41  comprises two blocking arms  46 , each of which, in the present example, forms one of the blocking elements  37 . To the extent that the blocking elements  37  are reduced to the angled terminal sections  40  at the ends of the blocking arms  46 , the blocking arms  46  themselves comprise the blocking elements  37 , namely, the terminal sections  40 . 
     In the present example, one of the two blocking elements  37  is arranged on one side of the gear-shift lever  2 , the other on the other side. As a result, the gear-shift lever  2  is supported symmetrically and without torque in the Park P position. It is also advisable to provide two separate blocking gates  38 , only one of which is shown in  FIG. 5 . The two blocking gates  38  are formed on a mounting bracket  47 , by means of which the gear-shift lever  2  is supported on the housing  12  pivotably around the pivot axis  35 . Each of the blocking elements  37  cooperates with one of the blocking gates  38 . 
     In the embodiment shown here, each of the blocking gates  38  is also equipped with an additional gate section  48 , which is assigned to the Neutral N position. The blocking element  37  cooperates in the Neutral N position with this additional gate section  48  and can engage therein to block the gear-shift lever  2 . An embodiment is especially effective in which, when the Park P position is present and the actuator  44  has not been actuated, the blocking element  37  engages in its assigned gate section  39  to block the gear-shift lever  2  in this Park P position. The two gate sections  39 ,  48  are arranged opposite each other in the blocking gate  38 . As a result, when the Neutral N position is present, the blocking element  37  engages in its assigned gate section  48  only when the actuator  44  is actuated and only then blocks the gear-shift lever  2  in this Neutral N position. 
     The blocking of the gear-shift lever  2  in the Park P position or in the Neutral N position is frequently also called the “shift lock”. It is clear that the shifting device  1  can be connected suitably to an ignition lock to allow the removal of the ignition key from the ignition lock only when the gear-shift lever  2  is in the Park P position and blocked by the blocking mechanism  36 , i.e., the so-called “key lock”. 
     The shifting device  1  is also equipped with a latching mechanism  49 , which can be seen especially clearly in  FIG. 6 . The latching mechanism  49  comprises the latching positions assigned to the gear-shift positions  9  of the gear-shift lever  2 . For this purpose, the latching mechanism  49  comprises at least one latching element  50 , which cooperates with a latching gate  51 . Said latching gate  51  comprises several gate sections. Each of these is assigned to a gear-shift position. Accordingly, four gate sections can be seen here, namely, a first gate section  52 , which is assigned to the Park P position, a second gate section  53 , which is assigned to the Reverse R position, a third gate section  54 , which is assigned to the Neutral N position, and a fourth gate section  55 , which is assigned to the Drive D position. The latching gate  51  is designed so that each of its gate sections  52 - 55  forms a stable latching position for the latching element  50  in each of the assigned shift positions  9 . The latching element  50  is pretensioned by the force of a spring into these stable latching positions. In addition, the latching element  50  can be moved out of these stable latching positions against the force of the spring. An embodiment is especially effective in which the latching mechanism  49  comprises two such latching elements  50 , each of which cooperates simultaneously with its assigned latching gate  51 . The second latching element  50  can be seen in  FIG. 5 , for example. One of the two latching elements  50  is thus located on one side of the gear-shift lever  2 , the other on the other side, as a result of which symmetric and torque-free support of the gear-shift lever can be realized. Accordingly, two latching gates  51  are also provided. 
     The latching element  50  in question is arranged in a guide  56  so that is free to move up and down. Said guide  56  is open toward the associated latching gate  51 , so that the latching element  50  in question can project out of the guide  56  under the force of a spring and engage in the latching gate  51 . An appropriate compression spring inside the guide  56  can be supported on the latching element  50 . 
     In the example, the latching elements  50  are arranged on the gear-shift lever  2 , namely, in particular together with their associated guides  56 . For this purpose, the gear-shift lever  2  is equipped here with a mounting bracket  47 , by which the gear-shift lever  2  is supported pivotably around the pivot axis  35 . This pivot axis  35  extends transversely to the direction of movement of the gear-shift lever  2  in the automatic shift track  6  and can thus be referred to in the following as the “transverse axis”  35 . The latching elements  50  are arranged here together with the guides  56  on this mounting bracket  47 . In contrast, the latching gates  51  are formed on the housing  12  or on the shift block or selector block  10 . 
     As shown in  FIG. 5 , the gear-shift lever  2  can be supported on the mounting bracket  47  pivotably around a longitudinal axis  57 , which extends transversely to the transverse axis  35 . The gear-shift lever  2  pivots around the longitudinal axis  57  when it moves in the transverse axis  8  between the two shift tracks  6 ,  7 . 
     Each latching gate  51  has transition sections  58  between the gate sections  52 - 55  assigned to the individual gear-shift positions  9 ; these transition sections are in the form of “hills” on the side facing the latching element  50 , whereas the gate sections  52 - 55  adjacent thereto are in the form of “valleys”. The latching gate  51  is adapted to its associated latching element  50  in such a way that the transition areas  58  form unstable transition points, from which the active spring forces automatically drive the gear-shift lever  2  into the one or the other adjacent stable latching position, each of which corresponds to one of the gear-shift positions  9 . As a result, the gear-shift lever  2  can be actuated in a highly convenient manner to select the various gear-shift positions  9  of the automatic shift track  6 . 
     The latching gate  51  in question, furthermore, can be designed in such a way and can cooperate with its associated latching element  50  in such a way that the Middle M position in the manual shift track  7  is a self-centering, stable gear-shift position. The gate section  55 , which forms a stable latching position for the Drive D position, is also assigned to the Middle M position. Accordingly the Middle M position, too, is self-centering and stable. 
     The latching element  50  has here a roller element  59 , which is in contact with the contour of the associated latching gate  51 . The rolling element  59  has comparatively low resistance, which makes it easy to shift, i.e., to actuate the gear-shift lever  2 , even at high retaining forces. 
     As shown in  FIGS. 7-9 , the shifting device  1  also comprises a centering mechanism  60 . This centering mechanism  60  pretensions the gear-shift lever  2  in the manual shift track  7  into the Middle M position with a centering action. In addition, the centering mechanism  60  is designed so that, when the gear-shift lever  2  is in the manual shift track  7 , it can be moved out of the Middle M position, i.e., into the upshift position + or into the downshift position −, only against a restoring force. The gear-shift lever  2  can be connected to said centering device  60  by moving it along the transverse track  8  into the manual shift track  7 . By moving the gear-shift lever  2  from the manual shift track  7  via the transverse track  8  into the automatic shift track  6 , the gear-shift lever  2  is disconnected from the centering mechanism  60 . Accordingly, the centering mechanism  60  can transmit forces to the gear-shift lever  2  only when this lever is moved into the manual shift track  7 . In contrast, the latching mechanism  49  can transmit forces to the gear-shift lever  2  regardless of whether the lever is in the automatic shift track  6  or in the manual shift track  7 . This means that the latching mechanism  49  is connected to the gear-shift lever  2  both in the automatic shift track  6  and in the manual shift track  7 . 
     According to  FIG. 6 , the latching mechanism  49  assigns one gear-shift lever position  61  to the upshift position + and another gear-shift lever position  61  to the downshift position −. In  FIG. 6 , these positions are designated  61 + and  61 −. Relative to the stable latching position assigned to the Middle M position, which is assigned to the gate section  55  assigned to the Drive D position, each of these two gear-shift lever positions  61  is located on the far side of an unstable transition point  58 ,  62 , away from which, and thus away from the stable latching position assigned to the Middle M position, the gear-shift lever  2  is driven by the spring force generated by the latching mechanism  49 . In other words, when the latching element  50  reaches the upshift position + in the latching gate  51 , it arrives in a gear-shift lever position  61 + which, in  FIG. 6 , is located to the right of the unstable transition point  62 , which, in  FIG. 6 , is located to the right of the gate section  55  assigned to the Middle M position or to the Drive D position. This means that the spring force which drives the latching element  50  out of its guide  56  drives the gear-shift lever  2  away from the said gate section  55 . A corresponding situation applies also to the downshift position −. In this downshift position −, the latching element  50  is located in the gear-shift lever position  61 −, which, in  FIG. 6 , is located to the left of the transition point  58 , which is adjacent to (in  FIG. 6  to the left of) the gate section  55  assigned to the Drive D and Neutral N positions. This means that, in this gear-shift lever position  61 − as well, that is, in the downshift position  61 −, the spring force acting on the latching element  50  drives the latching element  50  away from said gate section  55  and pushes it into the adjacent gate section  54 . 
     This special design brings about a significant change in the force acting on the gear-shift lever  2  when this lever reaches the upshift position + or the downshift position −. For, once the unstable transition point  58  or  62  is passed, the direction in which the spring force of the latching mechanism  49  acts reverses. This means in turn that the force which the driver must exert to move the gear-shift lever  2  into the upshift position + or into the downshift position − decreases significantly as soon as the position in question is reached or immediately before the position in question is reached. 
     In accordance with an especially advantageous embodiment, the centering mechanism  60  can now be adapted to the latching mechanism  49  in such a way that the restoring force of the centering mechanism  60  in the upshift position + and in the downshift position − is greater in each case than the spring force of the latching mechanism  49  acting in the opposite direction in the assigned gear-shift lever position  61 . As a result of this design, the restoring force of the centering mechanism  60  can automatically bring the gear-shift lever  2  out of the upshift position + or the downshift position − into which it is pretensioned by the spring force of the latching mechanism  49 , back into the Middle M position. 
     At least in  FIGS. 7-9 , the centering mechanism  60  comprises a pushrod  63 . This is arranged with freedom of bidirectional movement in a rod guide  64 . The rod guide  64  in the example is formed in the housing  12  or in the selector block  10 . The pushrod  63  is pretensioned with a centering action by two restoring springs  65  into a central location assigned to the Middle M position. The pushrod  63  comprises a driver receptacle  66 . At the end facing away from the grip  3 , the gear-shift lever  2  has a driver  67 , which, when the gear-shift lever  2  is moved into the manual shift track  7 , engages in the driver receptacle  66 . As a result, the gear-shift lever  2  is connected to the centering device  60 . 
     The rod guide  64  and/or the pushrod  63  comprises end-position dampers  68 . When the gear-shift lever  2  travels into the upshift position + and into the downshift position −, the end-position dampers  68  damp the arrival in the end position in question. For example, the pushrod  63  can be designed as a hollow body, which is suitable for accommodating the restoring springs  65 . Support points, on which the restoring springs  65  can be supported on the rod guide  64 , are formed on the housing  12  or on the selector block  10 . They cannot be seen in the diagrams given here, however. These support points project into an open side of the push rod  63 . Corresponding openings can be seen in  FIG. 9 , where they are designated by the number  69 . 
     The shifting device  1  is also equipped with an actuating slide  70 , which is provided for the operation of the actuating cable  11 . For this purpose, the actuating cable  11  can be connected suitably to the actuating slide  70 . The actuating slide  70  is also equipped with a driver receptacle  71 , which is clearly visible in  FIGS. 7 and 8 . The driver  67  of the gear-shift lever  2  can engage in this driver receptacle  71  when the lever is moved into the automatic shift track  6 . As a result, the gear-shift lever  2  is connected to the actuating slide  70  when the gear-shift lever  2  is moved into the automatic shift track  6 . The actuating slide  70  can then be moved bidirectionally with the help of the gear-shift lever  2 . For this purpose, a longitudinal guide  72  is also provided for the actuating slide  70 . The longitudinal guide  72  is formed in the housing  12  or in the selector block  10 . 
     In the Drive D position, the actuating slide  70  is positioned in its longitudinal guide  72  in such a way that its driver receptacle  71  is aligned with the driver receptacle  66  of the pushrod  63 . When the gear-shift lever  2  is moved in the transverse track  8 , the driver  67  therefore changes over from one of the two driver receptacles  66 ,  71  to the other. The shifting device  1  is also equipped with a locking element  73 , which, when the driver  67  moves out of the driver receptacle  71  of the actuating slide  70 , engages positively in a recess  74 , which is formed in the actuating slide  70 . The locking element  73  engaged in the recess  74  prevents the actuating slide  70  from being moved along the longitudinal guide  72 . When the driver  67  is moved into the driver receptacle  71  of the actuating slide  70 , the locking element  73  is pulled back out of the recess  74 . This can be realized by means of, for example, an actuating element  75 , which is connected to the locking element  73  and which is actuated or displaced by the driver  67  when the driver engages in the driver receptacle  71  of the actuating slide  70 . So that the locking element  73  engages in the recess  74  when the driver  67  travels out of driver receptacle  71  of the actuating slide  70 , a compression spring  76  can also be provided, which pretensions the locking element  73  in the direction toward the actuating slide  70 . 
     While preferred embodiments of the invention have been described herein, it will be understood that such embodiments are provided by way of example only. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the spirit of the invention. It is intended that the appended claims cover all such variations as fall within the spirit and scope of the invention.