MXPA97001928A - Change device for a speed change box - Google Patents

Abstract

The present invention relates to a gearbox for a gearbox, which has at least two gear wheel clutches for coupling in each case a gear wheel associated with its gearbox arrow, which has an arrow of changes that is movable, rotationally and axially mounted with respect to a gearbox enclosure, having at least one shifting element, fixedly fixed in terms of movement with respect to the shifting arrow, to activate the gear wheel clutches With axial movements of the shift arrow, which has a neutral position of the arrow of changes in relation to its axial movements, the neutral position corresponding to the decoupled state of all the gear wheel clutches, have significant angular positions of rotation the change arrow, wherein in each case at least one associated gear wheel clutch can be activated by the gear element. ambios, which has a gear speed position of the shift arrow corresponding to a coupled state of one of the gear wheel clutches associated with the significant rotational angle position, which has a servo motor to move the shift arrow in a first axial direction and a second axial direction, having a selector sleeve, which is used to activate the arrow of changes within the positions of significant rotation angles and is arranged concentrically and is axially movable with respect to the arrow of changes, and rotating and axially fixed in terms of movement relative to the gearbox enclosure, and in which device the shift arrow and the selector sleeve are connected together by an auxiliary mechanism to convert a reciprocating movement into a rotary movement and the auxiliary mechanism has a brake that can be in a coupling state and in a decoupling state and that s e connects in terms of action to one of the gearbox enclosure and the gearbox, characterized in that the change arrow is fixedly fixed in terms of movement in relation to an actuator element of the servo motor, which executes drive movements axial, and the selector sleeve is connected to the brake, and because the auxiliary mechanism allows relative rotation between the arrow of changes and the selector sleeve by an angle of rotation of difference that corresponds to the distance between two positions of significant angular rotation angle adjacent to the arrow of changes, when the arrow of changes is in the region of its neutral position, and because a locking mechanism arranged in terms of action is used between the gearbox enclosure of the gearbox and the arrow of changes for the significant rotation angle positions of the arrow of changes and the arrangement is also effected in a Such that the activation of the shift arrow from the gear speed position to the neutral position in the coupled state of the brake, leads to a rotation of the arrow of changes in the first rotational direction while in the uncoupled state of the brake, leads to a rotation of the selector sleeve in a second rotational direction in relation to the gearbox enclosure or the gearbox, in each case by the rotation angle of the differential.

Description

CHANGE DEVICE FOR A SPEED CHANGE BOX The present invention relates to a change device according to the preamble of patent claim 1. In a known shifting device of the type mentioned at the beginning (DE 41 37 142 A1) an electric servo motor is used, of which the Actuator element (motor shaft) which executes rotational drive movements is fixedly connected in terms of movement to the selector sleeve and is connected to the shift shaft by means of an additional clutch, engageable and detachable, while the brake is connected to the shaft arrow. changes and has to be built with an appropriate degree of freedom for the axial movements of the latter. In this known change device, it is considered essential that only one servo motor be used and that it be of an electrical nature, in such a way that the torque can be easily controlled by the current of the motor. However, in this known change device. the structural complexity and control is high as a result of the additional clutch, which inevitably has to be controlled in the opposite direction to the brake, ie if the clutch is open, in order to generate a translation activation of the change arrow for the change of gear - the brake must be engaged or vice versa, if the clutch is engaged - in order to generate a rotational activation of the arrow of changes to select the shift gates - the brake must be ventilated. Furthermore, in the case of this known change device, the control expense is further increased as a result of the fact that the servo motor has to be deactivated, when the change arrow reaches or separates from the region of the neutral position, such that the clutch and brake can be adjusted. In a known change device of another type (DE 09 027 Al), an axial piston that is connected directly to the arrow of changes and an axial piston that is connected to the arrow of changes by an auxiliary mechanism to convert a reciprocating movement in a rotational movement, they are accommodated in a common cylinder enclosure. In a further change device of another type, from the oldest application of German Patent 19530616.3-14 it has already become basically possible to jump one or more gears when changing speeds, in which case in order to activate the wheel clutches of gears, an equal amount of change elements are fixedly arranged in terms of movement with respect to the arrow of changes, specifically shifted with respect to each other in each case in the circumferential and axial directions. Correspondingly, the selector sleeve is provided with a corresponding assembly of window-like openings, for coupling the respective shift element with the associated gear wheel clutch, the shift shaft and selector sleeve, each having an actuator element operated by motor for its displacement. The objective on which the present invention is based essentially is to further reduce the structural complexity in the case of a change device of the type mentioned at the beginning, without losing the possibility of jumping gears when changing speeds. The object explained is advantageously achieved according to the invention having the characteristic features of the patent claim 1. In the shift device according to the invention, the selector sleeve driver is derived from the pulse of the change arrow by the auxiliary mechanism and the brake of the selector sleeve that provides the necessary reaction for this, such that a particular stepper motor is not necessary for the rotational displacement of the selector sleeve. While in the case of the change device forming the generic type in the oldest patent application, the selector sleeve is still additionally used to lock the clutches of the gear wheel which respectively do not engage the shift shaft and for this purpose, the same number of shift elements as gear wheel clutches is retained from the shift arrow, in the shift device according to the present invention, a shift element of the shift arrow can be used to activate the plurality of clutches of gear wheel because here, the selector sleeve does not have an interlocking function. In the case of the change device according to the invention, a change of speed gears in the same significant angle of the rotation position of the change arrow is advantageously carried out according to a method according to patent claim 2 In the case of the gearbox according to the invention, a gear change between two gear speeds located at one in positions of adjacent significant rotation angles, on each side of the neutral portion of the change arrow, is carried advantageously according to a method according to patent claim 3. In the case of the gearbox according to the invention, so that a gear change between two gear speeds located at significant angular positions of rotation adjacent to the same sense with respect to the neutral position of the arrow of changes, the method can be adopted according to the patent indication 3, which is then followed by a method step according to patent claim 2, or vice versa.

In the case of the shifting device according to the invention, a gear change between two gear speeds, located at significant non-adjacent rotation angle positions different from the shifting arrow, is advantageously carried out in accordance with a method according to the patent claim 4. In the case of a gear change according to the method according to patent claim 4, in order to keep the control complexity low, the change arrow in the case of the gear changes according to the The invention can be activated at respective gear speed positions at each of the significant rotational angle positions to be traversed until the target gear speed is reached. However, using the method according to patent claim 4, in the case of the gearbox according to the invention for a gear change between two gear speeds located at different non-adjacent significant rotation angle positions of the arrow of changes, the expense of changes and possibly a cost of synchronization for coupling and detachment of intermediate gears by a method according to patent claim 5, is advantageously avoided.

In the case of the gearbox according to the invention, a helical gear unit with a flat thread is used as an auxiliary mechanism to move the selector sleeve, in which case it may be possible for the selector sleeve to be made with the internal thread and the arrow of changes is made with the external thread. The patent claims 6 to 10 are directed to an advantageous refinement of the auxiliary mechanism in the case of the shifting device according to the invention in the form of a sliding guide in which a simpler control of the brake than in the case of a pure helical gear unit has been found of substantial advantage. Particularly structurally advantageous refinements of the shifting device according to the invention are the subject matter of patent claims 12 to 14. The invention is described in more detail below with reference to a mode schematically illustrated in the drawing, wherein: Figure 1 shows a perspective view of a change device according to the invention; Figure 2 shows a change device of Figure 1 in a view taken from the direction of the axis of rotation of the change arrow; Figure 3 shows a graphic illustration of the interaction of the shift arrow and the selector sleeve by the slide in the shift device of Figure 1 during a gear change; Figure 4 shows a graphic sequence of the change phases in the case of a gear change according to patent claim 2; Figure 5 shows a graphical sequence of change phases in the case of a gear change according to patent claim 3; Figure 6 shows a graphical sequence of change phases in the case of a gear change according to patent claim 4; and Figure 7 shows a graphical sequence of change phases in the case of a gear change according to patent claims 4 and 5. In a gearbox enclosure, only indicated with 11, a gearbox of speeds (not illustrated in more detail), a shift arrow 12, which aligns with its axis of rotation 24-24 parallel to the gearbox arrows, is rotatably mounted and axially displaceable. In order to couple the loose wheels of the gear wheel stages, supply the gearbox transmission ratios to their gearbox shaft, gear wheel clutches, which are activated either individually or in pairs and optionally by change forks 8, 9 and 10, are supported by the gearbox arrows, the shift forks 8, 9 and 10 each are connected in turn to a rail or associated shift rod 31-8, 31-9 and 31-10 fixedly in terms of movements. These change rods are both mounted to be moved linearly relative to the gearbox enclosure 11, in each case on a path of movement parallel to the axis of rotation 24-24, and each one is provided with the clutch groove 32. for the coupling of a shift finger 13, which is arranged radially and fixedly in terms of the movement with respect to the arrow of changes 12. In this context the arrangement is made in such a way that in the gearbox state, where all the gear wheel clutches are detached are detached, the shift finger 13 and all the clutch slots 32 are in a neutral position, ie they are located centrally with respect to the plane of the enclosure, which is located perpendicularly on the axis of 24-24 rotation. The shift rods 31-8, 31-9, 31-10 are fixed with their respective clutch groove 32 in relation to the gearbox enclosure 11, in each case in a position of rotation angle associated with the axis of rotation 24-24 of the arrow of changes 12. The arrow of changes 12 must according to this be activated in a single position of significant angle of rotation 12-8, if the finger of changes 13 must be in coupling, according to the Figures 1 and 2, with the shift rod 32 of the shift rod 31-8. The shift arrow 12 must be activated at a position of significant rotation angle 12-9 if the shift finger 13 is to be moved in engagement with the shift slot 32 of the shift rod 31-9. And the shift arrow 12 must be activated at a position of significant rotation angle 12-10, if shift finger 13 will be in engagement with the shift slot 32 of the shift rod 31-10. Each of the shift rods 31-8, 31-9 and 31-10 can be activated - starting from the neutral position - in the axial direction, pointing from the shift finger 13 to the arrow end 29 of the change shaft 12 , in position of gear speed a or in the opposite axial direction in a gear speed position d. In order to activate the shift arrow 12 at its two end positions associated with the gear speed positions a and d, the shift shaft 12 engages at its arrow end 29 a shift actuator member 14 of the axial piston type . In order to activate the shift arrow 12 to its significant rotation angle positions 12-8, 12-9, and 12-10, a selector sleeve 15 is employed which is connected to the shift arrow 12, mediated by a auxiliary mechanism 16 in order to convert a reciprocating movement into rotational movement, the gearbox reaction is mediated by a detachable and releasable brake 20 and the selector sleeve 15 likewise moves through the shift actuator 14. While the finger of changes 13 are arranged in a central section 30 of the shift arrow 12, the other end 28 of the shift arrow 12 is connected to a steelworking device 21 by which the shift arrow 12 is locked at its angle positions. significant rotation 12-8, 12-9 and 12-10, in relation to the gearbox enclosure 11. The selector sleeve 15 is arranged so as to be rotatable and axially non-displaceable relative to the gearbox enclosure 11 , in a way that is no longer illustrated. The selector sleeve 15 is arranged in the section of the shift shaft 12 located between the shift finger 13 and the shift actuating element 14, concentrically and in fact both rotationally movable and axially movable, relative to the shift shaft 12. The brake 20 is arranged in a positive locking manner in that sleeve end of the selector sleeve 15 facing the shift actuator 14., the selector sleeve 15 has here a steel segment 33 which is fixed in terms of movement with respect to it, and is provided in each case with a steel means for the rotation angle positions of the selector sleeve 15, in relation to the gearbox enclosure 11, a brake coupling element 34 is capable of engaging in a positive locking manner within the locking means, being capable of being activated by motor and disposed radially movable with respect to the axis of rotation 24-24 . A slide 22, fixedly arranged in terms of movement with respect to the selector sleeve 15, with a slide pin or block 23, arranged radially and fixedly in terms of movement with respect to the shift shaft 12, is used for the auxiliary mechanism 16. The slide 22 has two slide sections 25 and 26 running parallel to the axis of rotation 24-24 of the shift shaft 12 and moving in the circumferential direction with each other, specifically by a displacement 18 (Figure 3 (b)). corresponding to the difference in angle of rotation 17 (Figure 2), whereby the positions of adjacent angle of rotation 12-8 and 12-9 as well as 12-8 and 12-10 of the arrow of changes 12, are displaced from each other. Assigned to the slider ends 25-1 and 26-1 of the slider sections 25 and 26 located opposite one another in each case is a position a (Figure 3 (a)) and d (Figure 3 (d)) the pin slider 23, in this position corresponds to the respective end position of the shift shaft 12 and thus the gear speed positions a and d of the shift rods 31-8, 31-9 and 31-10. At the sliding ends 25-2 and 26-2 facing each other, the sliding section 25 and 26 are connected to each other by a central slider section 27 which extends in inclination with respect to the axis of rotation 24-24 of the change arrow 12 and in a form determined by the displacement 18. The central section 27 of the slide 22 is assigned to the neutral position N (Figure 3 (N)) of the slide pin 23 and thus the neutral position of the arrow of changes 12. The ends of slide 25-1 and 26-1 facing each other, the section of slide 25 and 26 circumscribe between them the region 19 (Figure 3 (b) and (c)) the position neutral N which is highly significant for the control of the shift arrow 12 by the brake 20. The position of the slide pin 23 in the joint 25-2 between the slide sections 25 and 27 is indicated by b (Figure 3 and ( b)). The position of slide pin 23 in the joint 26-2 between the slide sections 26 and 27 is indicated by C (Figure 3 (c)). The method of operation of the shifting device according to the invention is as follows: In Figures 1 and 2, the shifting device is illustrated in a state in which the shifting rod 31-8 is in the gear speed position. and the shift rod 12 is in the corresponding end position (position a of the slide pin 23) as well as in the position of significant rotation angle 12-8 for the engagement of the shift finger 13 within the shift slot 32 of the change rod 31-8. In the case of a gear change from the gear speed position a of the shift rod 31-8 to the selected gear speed with the same gate (gear speed position d of the shift rod 31-8) according to patent claim 2 and figure 4, the brake 20 is maintained in the detached state 20-0 and the shift arrow 12 is maintained in the position of significant rotation angle 12-8 by the steelworking device 21 The change arrow 12 is activated by the change activating element 14 in the end position corresponding to the gear speed position d, the selector sleeve without reaction 15 is rotated, as it passes through the region 19 in relation to the change arrow 12 by the slide pin 23 by means of displacement 18 in the direction of rotation indicating the change arrow 31-8 to the shift rod 31-10 - defined below as in the direction of the arrows clock tops. In the case of a gear change from the gear speed position a of the shift rod 31-8 to the gear speed position d of the adjacent shift rod 31-9, the brake 20 is maintained in accordance with Claim 13 Figure 5, in the coupled state 20-1 and the shift arrow 12 is activated by the shift activating member 14 within the end position associated with the shift speed position d, a rotational movement by the angle of rotation of difference 17 at the position of significant angle of rotation 12-9 imposed on the arrow of changes 12 by the sliding section 27, as the arrow of changes passes through region 12 of the neutral position N, the direction of rotation of the position of angle of rotation 12-9 is opposite to the direction of rotation of the selector sleeve (19) [sic], in the case of the change of gears previously described with the brake released 20. In the case of a change of engra naje from the position of gear speed a of the shift rod 31-8 to the gear speed position a of the shift rod 31-9, the change arrow 12 is initially activated, according to patent claim 3 and Figure 3 as described above, in the gear speed position d of the shift rod 31-9 in the coupled state 20-1 of the brake 20, an additional opposite activation of the shift shaft 12 according to patent claim 2 and FIG. 6, following such that the brake 20 is maintained in the released state 20-0 when the shift shaft 12 is move to the end position corresponding to the gear speed position a. In the case of a gear change from the gear speed position a of the shift rod 31-8 to the gear speed position d of the shift rod 31-10, the shift arrow is initially activated when the the brake 20, according to patent claim 2 and Figure 4, is released to the end position corresponding to the gear speed position d, as a result of which the selector sleeve without reaction 15 is rotated in the direction of the clock hands by the angle of rotation of difference 17, in relation to the arrow of changes. This is then followed by an opposite activation of the shift arrow 12 according to patent claim 3 and Figure 6 at the other end position in the engaged state 20-1 of the brake 20, such that a movement in the direction of the hands of the rotational clock by the angle of rotation of difference 17 at the position of significant angle of rotation 12-10, is imposed on the arrow of changes 12 for the coupling of the finger of changes 13 in the clutch slot 32 of the change rod 31-10. Finally, an opposite activation of the shift arrow 12 when the brake 20 is released at the end position corresponding to the gear speed position d, is carried out. In the case of the gear change described last, it has been found in particular that the desired direction of rotation of the shift arrow 12 can be achieved by determining the operational state of the brake 20 before the neutral position first passes after the start. of the gear change. A particular advantage of the slide guide 22-23 compared to a pure helical speed box, is clearly that as a result of the fact that the slide section 25-26 extends in parallel, the brake control 20 does not have to precisely fit the joints 25-2 and 26-2 with the inclined part of the extension of the slide section 27 of the neutral position N, but the state of the brake that is necessary for the gear change can already be achieved when it is still coupled the old gear speed. In view of the fact that in the case of the gear change described above, it was necessary for the shift shaft 12 to pass through the neutral position N repeatedly each time the operating state of the brake 20 changed and the shift arrow 12 was activated each time in its respective end position (position a or b of the slide pin 23) in the case of the gear change according to patent claim 5 and Figure 7, there is no doubt equally provision that the change shaft 12 pass through of the neutral arrow N repeatedly with corresponding adjustment of the brake 12, so that for example it passes from a first position of significant angle of rotation to a second position of non-adjacent significant angle of rotation, but does not include an activation of the arrow of 12 changes in their end positions until the position of significant rotation angle of the target gear speed has been reached. This will now be explained with reference to a gear change from the gear speed position a of the shift rod 31-10 to the gear speed position d of the shift rod 31-9. The shift rod 31-9 moves in the opposite direction to that of the clock handle in relation to the shift rod 31-10, such that according to Figure 7, the brake 20 is coupled to the start of the gear change (switching in the shift actuator 14) and a rotational movement in the counterclockwise direction to the amount from the angle of rotation of difference 17 to the position of adjacent significant rotation angle 12-8 is imposed on the change arrow 12 as it passes through the neutral position N of da c. When the shift arrow 12 reaches the position c, the brake 20 is released and the shift actuator 14 is adjusted, such that the shift arrow 12 passes through the reaction 19 and from the neutral position N from ca - that is, just before it reaches the gear speed position d of the significant rotation angle position 12-8 - as a result of which the rotational movement in the counterclockwise direction by the displacement 18- that is to say an amount corresponding to the angle of rotation of difference 17 - is imposed on the selector sleeve 15 which is without reaction in this context, such that the slide section 26 acquires its position corresponding to the position of significant angle of rotation 31-9. If the shift arrow now reaches position b after passing through the neutral position N, the brake 20 moves to the engaged state 20-1, and the shift actuating element 14 is adjusted such that a rotational movement in the counterclockwise direction by the rotation angle of difference 17 to the position of significant rotation angle 12-9, is imposed on the shift arrow 12 by the slide section 27 during activation in the direction of the end position corresponding to the gear speed portion d and the shift rod 31-9 is thus activated by the shift finger 13 in its gear speed position d which corresponds to the targeted target gear speed.

Claims (14)

1. CLAIMS 1.- Gearboxes for a gearbox, which has at least two gear wheel clutches for coupling in each case a gear wheel associated with its gearbox arrow, which has an arrow of changes that is movable, rotationally and axially, mounted with respect to a gearbox enclosure having at least one shifting element, fixedly fixed in terms of movement with respect to the shifting shaft, to activate the gear wheel clutches with axial movements of the arrow of changes that has a neutral position of the arrow of changes in relation to its axial movements, the neutral position corresponding to the detached state of all the gear wheel clutches, have significant rotation angle positions of the arrow of changes, where in each case at least one associated gear wheel clutch can be activated by the gear changes element that has a gear speed ratio of the shift arrow, which corresponds to the coupled state of a gear wheel clutch associated with a significant rotation angle position, which has a servo motor to move the shaft of changes in the axial directions it has a selector sleeve, which is used to activate the arrow of changes within the positions of significant angles of rotation, and is arranged concentrically and axially movable with respect to the arrow of changes, and rotatable and axially fixed in terms of movement with respect to the enclosure of gearbox, and wherein the arrow of changes and the selector sleeve are connected to each other by an auxiliary mechanism to convert a reciprocating movement in a rotary movement and the auxiliary mechanism has a brake that can be coupled and detached and that is connected in terms of action to one of the gearbox elements, characterized in that the arrow of changes is available e fixedly in terms of movement in relation to the actuator element, which executes axial drive movements, and the servo motor, and the selector sleeve is connected to the brake, and because the auxiliary mechanism allows relative rotation between the shift shaft and the selector sleeve by an angle of rotation of difference corresponding to the distance between two positions of adjacent significant rotation angle of the arrow of changes, when the arrow of changes is in the region of its neutral position, because the interlocking mechanism arranged in terms of action between the gearbox enclosure of the gearbox and the change arrow, is used for the significant rotation angle positions of the change arrow and the arrangement is also made in such a way that the activation of the change arrow from a gear speed position in the neutral position in the brake engaged state, i it nevitably leads a rotation of the arrow of changes in the rotational direction while in the released state of the brake, inevitably leads to a rotation of the selector sleeve in the other rotational direction in relation to the gearbox enclosure of the gearbox , in each case by the rotation angle of difference.
2. 2.- Method for controlling the arrow of changes to change between two positions of gear speed, located at a position of common significant rotation angle and on one side of the neutral position, in the case of a device according to the claim of patent 1, characterized in that when the arrow of changes passes through the neutral position, the brake is maintained in the detached state.
3. 3. - Method for controlling the arrow of changes to change between two positions of gear speed, located in a position of common significant rotation angle and on one side of the neutral position, in the case of a device according to the claim of patent 1, characterized in that when the arrow of changes passes through the neutral position, the brake is maintained in the coupled state.
4. 4. Method for controlling the arrow of changes to change between two positions of gear speed, located at a position of common significant rotation angle and on one side of the neutral position, in the case of a device according to the claim of patent 1, characterized in that when the arrow of changes passes through the neutral position alternately in the two axial directions, and as it passes through the axial direction, the brake is maintained in the engaged state and as it passes through the the other axial direction the brake is maintained in the detached state.
5. 5.- Method for controlling the arrow of changes to change between two positions of gear speed, located at a position of common significant rotation angle and on one side of the neutral position, in the case of a device according to the claim of patent 4, characterized in that after the change arrow has reached a position of significant angle of rotation that does not include the position of selected gear speed and after it has departed from the neutral position, but before a position of gear speed has been reached, the axial movement of the change arrow is adjusted to the other respective axial direction.
6. 6. Device for changes in accordance with patent claim 1, characterized in that a slide with a corresponding slide block is used for the auxiliary mechanism.
7. 7. - Changing device in accordance with patent claim 6, characterized in that the slide has two slider sections located respectively offset from each other, both in the directions of the axis of rotation of the arrow of changes and the angle of rotation of difference and that extend parallel to the axis of rotation.
8. 8. Device for changes in accordance with patent claim 7, characterized in that of the sliding ends of the sliding sections that are located opposite each other, at least one sliding end is assigned to a gear speed position of the arrow of changes.
9. 9. Device for changes in accordance with one of the patent claims 6 to 8, characterized in that the slide has a central slider section that extends in inclination with respect to the axis of rotation of the arrow of changes, and the section of Central slide is assigned to the neutral position of the arrow of changes.
10. 10. Device for changes in accordance with patent claim 9, characterized in that the triggering of a control signal for adjusting the arrow of change towards the axial direction indicating the other section of the slide assigned to the gear speed section, it is provided at the joint between the slider section assigned to the neutral position and a slider section assigned by its slider end to a gear speed position.
11. 11. Device for changes in accordance with one of the patent claims 6 to 10, characterized in that the slide is fixedly fixed in terms of movement with respect to the selector sleeve.
12. 12.- Device of changes in accordance with patent claim 1, characterized in that the arrow end of the change arrow is connected to the acerrojamiento device and the other arrow end of the arrow of changes is connected to an actuator element of changes, because the change element is arranged in a central arrow section of the change arrow and the selector sleeve is arranged in an arrow section of the change arrow located between the change actuator element and the change element, and because the brake is arranged on the sleeve end of the selector sleeve facing the shift actuator element.
13. 13. Device for changes in accordance with patent claim 1, characterized in that the clutches of the gear wheel are activated by the shift rods that are arranged both parallel to the axes and in the same axial region with respect to the axis of rotation of the arrow of changes and axially mobile with respect to the enclosure of gearboxes and each one has a clutch slot for coupling a finger of changes that is used as an element of changes.
14. 14. Device for changes in accordance with patent claim 1, characterized in that the brake positively engages and the selector sleeve has a locking segment with locking means assigned to the significant positions of rotation angle of the shift arrow, for coupling of a brake coupling element, which can be moved radially with respect to the axis of rotation of the shift shaft.