WO2011047773A1

WO2011047773A1 - Shifting device for shifting gear stages of a transmission

Info

Publication number: WO2011047773A1
Application number: PCT/EP2010/005916
Authority: WO
Inventors: Arne Voigt; Wolfgang Vöge
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2009-10-21
Filing date: 2010-09-29
Publication date: 2011-04-28
Also published as: DE102009050150A1

Abstract

The invention relates to a shifting device (1) for shifting the gear stages of a transmission, comprising a shifting shaft (2), a shift finger (3), and several shift rails (4, 5, 6, 7). The shift finger (3) is rotationally fixed to the shifting shaft (2). At least one of the shift rails (4, 5, 6, 7) can be selected by a selecting movement of the shifting shaft (2). The shift rails (4 to 7) can be moved by a shifting movement of the shifting shaft (2). By means of the shifting movements and/or the selecting movements, at least one of the shift rails (4, 6, 7) can be moved into a gear-end position and at least one other shift rail (4, 5, 6, 7) can be arranged into a neutral position. At least one blocking area (8, 9) is provided, and the shift rail (4, 5, 6, 7) arranged in the neutral position is blocked from moving by means of the blocking area (8, 9). In order to avoid a complex design of the shift rails (4, 5, 6, 7) and the shifting shaft (2) and to avoid a complicated movement of the shifting shaft (2) for shifting, the shifting device (1) for shifting gear stages of a dual clutch transmission is designed wherein two of the provided shift rails (4, 5, 6, 7) can be moved into a gear end position, and the other shift rails (4, 5, 6, 7) can be arranged into the neutral position; a resetting area (10, 11) is provided, and the resetting area (10, 11) is designed such that a shift rail (4, 5, 6, 7) arranged in the gear end position can be moved into the neutral position by means of the resetting area (10, 11) during a selecting movement of the shifting shaft.

Description

description

Switching device for switching the gear ratios of a transmission

The invention relates to a switching device for switching the gear ratios of a transmission, with a shift shaft, with a shift finger and with a plurality of shift rails, wherein the

Shift finger is rotatably connected to the shift shaft, wherein at least one of the shift rails can be selected by a selection movement of the shift shaft, wherein by a

Switching movement of the shift shaft, the shift rails are displaceable, wherein at least one of the shift rails in a final gear position is displaceable by the switching movements and / or the Wählbewegungen and at least one other shift rail in one

Neutral position can be arranged, wherein at least one blocking area is provided and wherein the arranged in the neutral position shift rail is locked by means of the blocking area against displacement.

In the prior art, switching devices for switching manual transmissions are known. These switching devices usually have a switching shaft, a shift finger and a plurality of shift rails. The shift finger is rotatably connected to the shift shaft or integrally formed on the shift shaft. The switching shaft is movable in the axial direction to select the alley. This axial movement is referred to as selection movement. Further, the shift shaft with the shift finger in the rotational direction for engaging and disengaging the respective gear stages by means of the shift rails movable. The shift rails each have a shift jaw, in which the shift finger can be inserted axially. By rotation of the switching shaft, the respective selected shift rail is displaced substantially perpendicular to the longitudinal extent of the shift shaft. The shift rails each actuate a sliding sleeve of a synchronizer. The synchronizers can be designed as double-acting synchronizers, so that a displacement of the shift rail in one direction a first gear, for example. First gear inserts and the shift of the shift rail or the shift sleeve in the opposite direction another other gear, for example second gear. Depending on the direction of rotation during the switching movement can be switched so different gear ratios. The shift rails are displaceable by the shift finger in each case a final gear position to both sides. There are therefore vzw. two gear end positions provided for each shift rail. Furthermore, the shift rail is in a neutral position between the two gear positions

CONFIRMATION COPY

l can be arranged or displaced in this. A gear change takes place by rotation of the shift shaft from a gear end position to the neutral position, whereby initially the last engaged gear is designed. Thereafter, either with the same shift rail, ie in the same plane by continued rotation or switching movement of the shift finger the

Shift rail can be moved to the opposite gear end position, or by an axial selection movement of the shift finger can be moved to the next switching level, in which the shift finger then by re-rotation located in the neutral position

Shift rail can move, which then the next target gear is inserted. In manual transmissions a selection movement and a switching movement by a

Movement of the gearshift lever. When the gear shift lever is moved in the lane, the shift shaft executes the selection movement. When the gearshift lever is moved perpendicular to the lane to engage the gears, the shift movement is performed with the shift shaft.

In automatic transmissions, the movement of the shift shaft is no longer carried out by a movement of a gearshift lever, but the shift shaft is moved by two actuators. One of the actuators is for the selection movement of the shift shaft and the other actuator is provided for the rotational movement / switching movement of the shift shaft. The actuators can z. B. electric motor or hydraulically driven.

In the prior art motorcycle gearboxes are also known, the switching functions are performed with so-called shift rollers. The shift drums have at their

Outer circumference of a special profile. For example, channels can be milled into the shift drum, wherein the shift rails or shift forks engage with corresponding guide pins in these channels. If the shift drum is rotated, the guide pins are moved axially in the channels according to the course of the channels. By moving the

Guide pins are moved the shift rails. By moving the

Shift rails are in turn shifted axially synchronizers or shift dogs, whereby the corresponding gear is engaged or designed. Shift drums require only one rotary actuator. The disadvantage of a shift drum, however, is that the gear ratios are sequentially, ie sequentially switched in a fixed, unchangeable sequence. The skipping of gear stages is not possible without interposing the intermediate gears, whereby the gear change speed and thus the ride comfort

is restricted. To switch, for example, from the fourth gear in the first gear, the intermediate gear stages two and three must also be engaged and can not be skipped.

Both manual transmissions and automated manual transmissions can

Depending on the system, only a maximum of one gear can be engaged at any one time. In the prior art double clutch transmissions are also known. Dual-clutch transmissions have two independent transmission branches. The driving power of the

Drive motor can be transmitted via a drive shaft via a respective friction clutch to one of the two transmission branches. When changing gear, the pulling force is not interrupted. This is achieved by the fact that exactly two gears are engaged at the same time. The even-numbered gear stages are the one transmission branch and the odd-numbered gear ratios are assigned to the other transmission branch. In a gear change now one of the two friction clutches is opened and the other friction clutch simultaneously

closed. It is therefore necessary for the preparation of the gear change that with the switching device for switching the dual-clutch transmission two shift rails are displaceable in a final gear position and the other shift rails are arranged in the neutral position. If, for example, three shift rails are provided, then there are two in the final gear position and a shift rail is in the neutral position.

In the prior art, switching devices for switching a dual-clutch transmission are known, wherein a shift drum, each with a rotary actuator is used. This has the disadvantage that the switching speed is limited at gear jumps.

From DE 101 19 748 A1 discloses a switching device for a dual-clutch transmission is known. This switching device has a switching shaft with a shift finger and several

Shift rails on. The shift rails each have a switching mouth, in which the

Shift finger can intervene. Although some of the shift rails are located in a final gear position, there remains a neutral alley that is wide enough to permit dialing movement of the shift finger. This is achieved in that the shift mouth width is equal to or greater than the sum of shift finger width and the distance between the neutral position and the final gear position of the shift rail. Between the shift finger and the shift rail is a game that is equal to or greater than the path of the shift rail between the

Neutral position and the final gear position is.

From US 2006/0150761 A1 and EP 1 561 055 B1, a switching device with a switching shaft, a plurality of shift fingers and a plurality of shift rails is known. On the

Shift shaft control cam-like, the radially outwardly facing shift fingers are formed. The Schaltschieneri each have a switching mouth, in each of which one of the shift fingers can engage in an axial displacement of the shift shaft. By turning the

Shift shaft about its longitudinal axis then move the shift finger one or more of the shift rails. At the shift fingers and / or on the shift shaft recesses are formed with oblique side walls into which a locking cam can engage. These Locking cams are formed on the shift rails and protrude radially in the direction of

Shift shaft or in a lateral recess of the shift finger. The locking cams allow that only a very specific shift finger can engage in the shift rail with the shift jaw only in a certain rotational position of the shift shaft. In all others

Shifting or twisting positions of the shift shaft locks the respective locking cam engagement of the shift finger in the associated shift jaw of the shift rail.

From WO 2005/114010 A1 a generic switching device with a switching shaft, a shift finger and a plurality of shift rails is known. The shift rails each have a shift mouth in the form of a groove. The shift rails also have an actuating contour and a locking radius. The switching shaft has a projecting locking element, wherein the radius of the switching shaft in the region of the shift finger is smaller than the radius of the

Locking element. The projecting locking element can engage in the locking radius on the shift rails and forms a blocking area. It is always switched only one gear, all other shift rails are blocked by the blocking element. Ie. a shift rail is arranged in the gear end position and the other shift rails are prevented in the neutral position by the blocking element in the movement. A disadvantage of this switching device is that even if the shift finger is turned back to the neutral position of the shift rail, the other shift rails are still blocked by the locking element. The movement of the shift shaft for shifting the gear stages is complicated. The design of the shift shaft and the shift rails is expensive. This switching device is therefore not yet optimally formed.

The invention is therefore based on the object, the above-mentioned switching device in such a way and further develop that a complex configuration of

Shift rails and the shift shaft and a complicated movement of the shift shaft is avoided for switching.

This object of the invention is achieved in that the

Switching device is designed for switching the gear ratios of a dual-clutch transmission, wherein two of the shift rails are displaceable in a gear end position and the other shift rails can be arranged in the neutral position, wherein a return range is provided and the return range is formed so that in a selection movement of the shift shaft by means of the return range a arranged in the final gear shift rail is displaceable in the neutral position. This has the advantage that a now no longer selected shift rail from the gear end position is forcibly coupled in the neutral position by the reset area during the selection movement. Here, the selection movement or the axial displacement of the shift shaft is used to change to another Switching level or another shift rail to achieve the Zwangsausiegen the previously active gear or the previously active shift rail. The reset areas can be formed by a special shape of the switching shaft. For example. can he

Restoring area be at least partially conical. Alternatively or additionally, a blocking region can be formed by further components or an assembly on the switching shaft. During axial displacement of the switching shaft of the return range engages the

Schaltmaul the shift rail so that the shift rail in the neutral position

is pushed back. The reset area is followed by the blocking area. That

After the shift rail has been reset and the shift shaft is further axially displaced, blocked area blocks a shift of the shift rail. The disadvantages mentioned above are therefore avoided and achieved corresponding advantages.

There are now a variety of ways to design the switching device according to the invention in an advantageous manner and further. For this purpose, reference may first be made to the claims subordinate to claim 1. In the following, a preferred embodiment of the invention will now be explained in more detail with reference to the drawing and the associated description. In the drawing shows:

1 is a schematic, perspective view of a switching device with a switching shaft and with a plurality of shift rails, wherein a first gear is engaged,

2 is a schematic, perspective view of the switching device, wherein the first gear and a second gear is engaged,

3 is a schematic, perspective view of the switching device, wherein the second gear and a third gear is engaged,

4 is a schematic, perspective view of the switching device, wherein the third gear and a fourth gear is engaged,

5 is a schematic, perspective view of the switching device, wherein the fourth gear and a fifth gear is engaged,

Fig. 6 is a schematic, perspective view of the switching device, wherein the fifth gear and a sixth gear is engaged, and Fig. 7 is a schematic, perspective view of the switching device, wherein the sixth gear and a seventh gear is engaged.

In FIGS. 1 to 7, a switching device 1 for switching a transmission, not shown, is clearly visible.

The switching device 1 has a switching shaft 2. The switching device 1 further comprises a shift finger 3. The shift finger 3 extends substantially radially to the shift shaft 2. The shift finger 3 is substantially perpendicular from the shift shaft 2 from. The shift finger 3 is rotatably and axially immovably connected to the shift shaft 2. The shift finger 3 is vzw. formed as an integral part of the switching shaft 2.

The switching device 1 also has a plurality of shift rails, namely the four shift rails 4, 5, 6 and 7. The shift rails 4 to 7 can be arranged in three different positions, namely in two gear end positions and in an intermediate

Neutral. The final gear position corresponds to an engaged gear. Vzw. Each shift rail 4 to 7 are assigned two gear ratios. The shift rail 4 is the first gear and the third gear assigned. The shift rail 5 is the

Reverse gear (in Fig. 1 to 7 denoted by R) and the second gear assigned. The shift rail 6 is the fourth gear and the sixth gear assigned and the shift rail 7 is the seventh gear and the fifth gear assigned. The term "first gear" is to be equated here with the term "1st gear", the term "second gear" with the term "2nd gear", etc.

By a selection movement of the switching shaft 2, at least one of the shift rails 4 to 7 can be selected. The shift finger 3 is in the "initial position" of the shift shaft 2 while in

Substantially axially arranged at the level of the selected shift rail 4. In Fig. 1, the shift rail 4 is selected, wherein the shift rail 4 is arranged in the final gear position of the first gear, d. H. in Fig. 1, the shift rail 4, in contrast to the shift rails located in the neutral position 5, 6, 7 shifted to the right by the scarf fingers 3. The selection movement is vzw. executed by an axial movement of the switching shaft 3.

In Fig. 2 it is shown that the switching shaft 2 has now carried out, inter alia, a selection movement, so that the shift finger 3 is arranged in the plane of the shift rail 5. With the switching shaft 2, a switching movement is also executable. The shift rail 5 shown in Fig. 1 in the neutral position is now shifted by rotation of the shift shaft 2 in Fig. 2 to the left in the final gear position, whereby the second gear is engaged. In Fig. 2 are the Shift rails 4, 6 and 7, as arranged in Fig. 1, so that according to FIG. 2, only the first and the second gear stage are inserted. By switching movements and Wählbewegungen at least one of the shift rails 4 to 7 is displaceable in a final gear position and the other shift rails can be arranged in the neutral position, as shown. The selection and / or switching movement can via corresponding actuators, vzw. be realized electrically or hydraulically.

The selection movement is formed here as an axial displacement of the shift shaft 2. The

Switching movement is formed as a rotation or rotation of the switching shaft 2.

In principle, the arrangement of the selection and switching movement can also be exchanged, d. H. the selection movement can also be rotational and the switching movement translational, d. H. be carried out by an axial displacement.

The switching device 1 further has at least one blocking area here vzw. two

Locking areas 8, 9 on. The blocking area 8, 9 is in each case vzw. formed on the shift shaft 2. The diameter of the switching shaft 2 is chosen in the restricted area 8, 9 so large that the

Shift rails 4, 5, 6, 7 in the amount of the blocking area 8, 9 are locked by the blocking area 8, 9 in the neutral position against displacement. At least one of the shift rails 4 to 7 arranged in the neutral position is locked against displacement by means of the blocking area 8, 9. In Fig. 1 it can be seen that the shift rail 7 is blocked by the blocking area 9 against displacement. In Fig. 2 it can be seen that the shift rails 6, 7 are locked by the blocking area 9 against displacement.

The disadvantages mentioned above are now avoided in that the switching device 1 is designed for switching the gear ratios of a dual-clutch transmission, wherein two of the shift rails 4, 5, 6, 7 are displaceable in a final gear position and the other

Switching rails 4, 5, 6, 7 are arranged in the neutral position, wherein a return portion 10, 11 is provided and the return portion 10, 11 is formed so that at a

Selection movement by means of the return range 10, 11 one in a final gear position

arranged shift rail 4, 5, 6, 7 is displaceable in the neutral position. This has the advantage that the changeover to another switching level or shift rail 4 to 7 is used to achieve the forced removal of a previously active gear stage of the same transmission branch. For this purpose, the switching shaft 2 has a special shape. In an alternative embodiment, the switching shaft 2 may have an assembly or multiple assemblies, realized by the shaping.

The switching shaft 2 has vzw. two blocking regions 8, 9 and between the two blocking regions 8, 9 an actuating region 12, wherein in the operating region 2 of the shift finger 3rd is arranged and between the blocking area 8, 9 and the actuating portion 12 each one of the return areas 10, 11 is formed. The blocking regions 8, 9 have a larger diameter than the actuating region 12, wherein the restoring regions 10, 11 taper from the blocking regions 8, 9 towards the actuating region 12. The

Reset areas 10, 11 are essentially conical here. The blocking areas 8, 9, the return areas 10, 11 and the operating area 12 have vzw. a round, in particular circular cross-section, each with a different diameter.

Between the two return areas 10, 11 of the actuating portion 12 is provided. The shift finger 3 is arranged in the operating area 12. The actuation region 12 has a smaller diameter than the return regions 10, 11 and also as the blocking regions 8, 9. The blocking regions 8,9 and the actuating portion 12 have vzw. essentially a cylindrical shape. In the reset areas 10, 11, the shift shaft 2 tapers to the actuation area 12. By the reset areas 10, 11, the respective currently selected shift rail 4 to 7 adjacent shift rail 4 to 7 from her

Gangendstellung pushed back into the neutral position when the shift finger 3 is moved away from this adjacent shift rail 4 to 7. The difference in radius between the blocking area 8.9 and the actuating area 12 corresponds to VZV. essentially the

Displacement of the shift rails 4, 5, 6, 7 between the final gear position and the

Neutral.

The shift rails 4, 7 each have a shift jaw 13, 14, 15, 16. In the shift jaw 13, 14, 15, 16, the shift shaft 2 engages. By the switching movement of the shift shaft 2 of the shift finger 3 engages the selected shift rail 4, 5, 6, 7 on the unspecified inner wall of the shift jaw 13, 14, 15, 16, so that the shift rail 4, 5, 6, 7 is moved accordingly.

The Schaltmäuler 13, 14, 15 are vzw. each formed so wide that in the Gangendstellung the respective shift rail 4, 5, 6, 7 of the shift finger 3 is moved back into a neutral neutral unspecified, without that respective shift rail 4, 5, 6, 7 is shifted from the final gear position. The Schaltmäuler 13, 14, 15, 16 are therefore so wide

are formed, that the shift rails 4, 5, 6, 7 can be arranged in the respective Gangendstellung while the Schaltmäuler 13, 14, 15, 16 then form a neutral lane, wherein the peeling finger 3 in the neutral lane without moving the respective shift rails 4, 5, 6, 7 is moved back. The width of the Schaltmäuler 13, 14, 15, 16 is equal to or greater than the sum of the width of the shift finger 3 and the distance between the neutral position and the Gangendstellung the shift rail 4, 5, 6, 7. To the illustrated switching shaft 2 two To engage gear ratios at the same time, have the Schaltmäuler 13 to 16 the corresponding width, so that after inserting a gear, a backward movement of the shift finger 3 in the neutral lane is possible without interposing the engaged gear again. Under switching jaw 13, 14, 15, 16 is understood here the opening of the shift rails 4 to 7, in which the shift shaft 2 projects with its shift finger 3. The Schaltmäuler 13, 14, 15, 16 have two vzw. parallel opposite inner walls and a connecting the inner walls arc wall portion (not specified) on. The Schaltmäuler 13, 14, 15, 16 are substantially vzw. U-shaped. Also, an O-shaped or rectangular-shaped training is conceivable.

Vzw. For example, each of the shift rails 4 to 7 has only gear stages of the same transmission branch. The shift rails 4 to 7 are vzw. arranged next to each other, with neighboring ones

Shift rails 4, 5, 6, 7 are assigned to different transmission branches. a

Transmission branch are the even gears two, four, six and the reverse gear and the other transmission branch are the odd gear stages one, three, five and seven assigned. Accordingly, the shift rails 5, 6 associated with a gear branch with the even gears and the reverse gear and the shift rails 4 and 7 the transmission branch with the odd gear ratios.

Neighboring gears are vzw. associated with adjacent shift rails 4, 5, 6, 7. The two shift rails 4, 6 are arranged adjacent in the middle. The shift rail 5 is disposed adjacent to the shift rail 4 on the outside. The shift rail 7 is disposed adjacent to the shift rail 6 outside. The first gear is assigned to the substantially arranged in the middle shift rail 4. The second gear is assigned to the arranged adjacent to the shift rail 4 shift rail 5. The third gear is in turn assigned to the adjacent shift rail 4. The fourth gear is associated with the shift rail 6 adjacent to the shift rail 4. The fifth gear is associated with the shift rail 6 adjacent, outer shift rail 7. The sixth gear is in turn assigned to the middle, adjacent shift rail 6. The seventh gear is finally assigned to the adjacent outer shift rail 7.

The axial length of the actuating region 12 corresponds to VZH. This is particularly evident in Fig. 3, in which the shift rail 5 is disposed adjacent to the return portion 10 and the shift rail 6 also still in the operating area 12, but adjacent to the

Reset area 11 is arranged. The shift finger 3 is vzw. in the middle between the

Return range 10 and 11 arranged. In Fig. 1 can be clearly seen that the first gear is engaged. The shift rail 7 is blocked by the blocking area 9. The shift rail 5 and the shift rail 6 are arranged in the amount of the actuating portion 12 and are held by not shown detents in the neutral position.

In Fig. 2 it can be seen that now the first and the second gear are engaged. The shift rails 6 and 7 are blocked by the blocking area 9 against displacement.

In the position shown in Fig. 3, the second and the third gear stage are engaged. The shift rail 6 is disposed at the level of the actuating portion 12 and is held by a detent in the neutral position. The shift rail 7 is blocked by the blocking area 9 against displacement.

In Fig. 4 it can be seen that the third and fourth gear are engaged. Compared to Fig. 3, the shift shaft 2 has now been moved axially, so that the return portion 10 has forced the shift rail 5 in the neutral position. The shift rail 5 is in the

Neutral position shifted as soon as the shift finger 3 has reached the level of the shift rail 6. The shift rail 7 is disposed at the level of the actuating portion 12 and is in turn held by a detent in the neutral position.

Fig. 5 shows how the fourth and the fifth gear are engaged. The shift rail 5 is blocked by the blocking area 8 against displacement. The shift rail 4 is forced by means of the return portion 12 in the neutral position as soon as the shift finger 3 is brought into the plane of the shift rail 7.

Fig. 6 shows how the fifth and the sixth gear are engaged. The shift rail 5 is blocked by the blocking area 8 against displacement. The shift rail 4 is held by a detent in the neutral position.

In Fig. 7 shows how the sixth and seventh gear are engaged. The shift rail 5 and the shift rail 4 remain blocked by the blocking area 8 against displacement. The shift rail 7 has now been moved by the shift finger 3 by means of a selection movement and a subsequent switching movement in the final gear position for the seventh gear.

With the thus formed switching device or in a dual-clutch transmission with such a switching device, the disadvantages mentioned above are therefore avoided and achieved corresponding advantages. LIST OF REFERENCE NUMBERS

switching device

shift shaft

shift finger

shift rail

stopband

Reset section

operating range

shift mouthpiece

Claims

claims

1. switching device (1) for switching the gear ratios of a transmission, with a switching shaft (2), with a shift finger (3) and with a plurality of shift rails (4, 5, 6, 7), wherein the shift finger (3) rotatably with the shift shaft (2) is connected, by a

Selective movement of the shift shaft (2) at least one of the shift rails (4, 5, 6, 7) is selectable, wherein by a switching movement of the shift shaft (2) the shift rails (4 to 7) are displaceable, wherein by the switching movements and / or

Wählbewegungen at least one of the shift rails (4, 6, 7) is displaceable in a final gear position and at least one other shift rail (4, 5, 6, 7) in one

Neutral position can be arranged, wherein at least one blocking area (8, 9) is provided and wherein the arranged in the neutral position shift rail (4, 5, 6, 7) by means of the blocking area (8, 9) is locked against displacement, characterized in that the Switching device (1) is designed for switching the gear ratios of a dual-clutch transmission, wherein two of the provided shift rails (4, 5, 6, 7) in a

Gangendstellung are displaced and the other shift rails (4, 5, 6, 7) can be arranged in the neutral position, wherein a return range (10, 11) is provided and the return portion (10, 11) is formed so that during a selection movement of the shift shaft (2) by means of the return range (10, 11) arranged in the final gear position shift rail (4, 5, 6, 7) is displaceable in the neutral position.

2. Switching device according to claim 1, characterized in that the switching shaft (2) has two blocking regions (8, 9) and between the two blocking regions (8, 9) a

Operating range (12), wherein in the operating region (12) of the shift finger (3) is arranged and between the respective blocking region (8, 9) and

Operating range (12) each one of the return areas (10, 11) is formed.

3. Switching device according to claim 1 or 2, characterized in that the

Barrier areas (8,9) have a larger diameter than the actuating area (12), wherein the return areas (10, 11) taper from the blocking areas (8,9) to the actuating area (12).

4. Switching device according to one of the preceding claims, characterized in that the difference in radius between the blocking region (8, 9) and the actuating region (12) is substantially the displacement of the shift rails (4, 5, 6, 7) between the final gear position and the neutral position.

5. Switching device according to one of the preceding claims, characterized in that the return areas (10, 11) are conical.

6. Switching device according to one of the preceding claims, characterized in that the distance between the two return areas (10, 1 1) substantially equal to the distance of three adjacent shift rails (4, 5, 6, 7).

7. Switching device according to one of the preceding claims, characterized in that the shift finger (3) is arranged substantially centrally between the two return areas (10, 11).

8. Switching device according to one of the preceding claims, characterized in that the shift rails (4, 5, 6, 7) Schaltmäuler (13, 14, 15, 16) and the Schaltmäuler (13, 14, 15, 16) formed so wide are that the Schaltmäuler (13, 14, 15, 16) form a neutral lane, wherein the shift finger (3) in the neutral lane without

Moving the shift rails (4, 5, 6, 7) is axially movable.

9. Switching device according to one of the preceding claims, characterized in that the width of the Schaltmäuler (13, 14, 15, 16) equal to or greater than the sum of the width of the shift finger (3) and the distance between the neutral position and the Gangendstellung the shift rail (4, 5, 6, 7).

10. Switching device according to one of the preceding claims, characterized in that the respective shift rail (4, 5, 6, 7) only gear stages of the same

Transmission branches are assigned.

11. Switching device according to one of the preceding claims, characterized in that the shift rails (4, 5, 6, 7) are arranged side by side, wherein each adjacent shift rails (4, 5, 6, 7) are associated with different transmission branches.

12. Switching device according to one of the preceding claims, characterized in that adjacent gear stages adjacent switching rails (4, 5, 6, 7) are assigned.

3. Switching device according to one of the preceding claims, characterized in that the reverse gear is associated with one of the shift rails (5), wherein an adjacent shift rail (4) is associated with the first or the second gear.