WO2015117777A1

WO2015117777A1 - Shifting device for a planetary gearbox

Info

Publication number: WO2015117777A1
Application number: PCT/EP2015/050139
Authority: WO
Inventors: Ewald Schmitz; Frank Richter
Original assignee: Zf Friedrichshafen Ag
Priority date: 2014-02-04
Filing date: 2015-01-07
Publication date: 2015-08-13
Also published as: DE102014201970A1; TW201531636A

Abstract

The invention relates to a shifting device (5) for a gearbox, in particular a two-stage planetary gearbox, comprising a rotatable shifting sleeve (10) which, for shifting the gearbox, is able to be displaced along its axis of rotation (27) into at least one shift position, wherein the shifting sleeve (10) has a connection region (6) in which said shifting sleeve can be connected to a drive shaft (1) of the gearbox in such a way that a rotational movement of the drive shaft (1) can be transmitted to the shifting sleeve (10), and comprising at least one stationary shifting element (8) which, when actuated to displace the shifting sleeve (10) axially into the shift position, can be coupled to said shifting sleeve in a form-fitting manner. According to the invention, the shifting sleeve (10) has in the circumferential direction a stop (32), against which the actuated shifting element (8) can butt so that a rotational movement of the shifting sleeve (10) is stopped relative to a rotational movement of the drive shaft (1).

Description

Switching device for a planetary gearbox

The present invention relates to a switching device for a planetary gear according to the closer defined in the preamble of claim 1. Art.

Shifting devices for transmissions, in particular planetary gears, are used, for example, in machine tools, turning, milling and machining centers. The drive motors are DC / AC main spindle motors. The gearboxes increase the power range of the main spindle motors in order to increase the flexibility of the machine tools when machining different materials or cutting forces due to high torques or speeds. In previously known planetary gearboxes for machine tools two translation stages are formed.

From DE 10 2009 054 942 A1 discloses a switching device for a change-speed gearbox is known, which has at least one sliding sleeve, which is mounted rotationally fixed and axially displaceable on a gear shaft. To each of these sliding sleeve a loose wheel is placed adjacent at least on one side, which is arranged freely rotatable on the transmission shaft. The at least one sliding sleeve is axially movable in the direction of each one idler gear in a switching position by an actuation of associated adjusting means from a neutral position. Upon reaching the switching position, a coupling of each one idler gear is caused with the transmission shaft. The associated adjusting means are arranged stationary and engage when actuated in at least one switching groove. The shift groove is provided on an outer diameter of the at least one sliding sleeve. It has a curved course in the axial direction. As a result, an axial displacement of the at least one sliding sleeve is caused in accordance with the course of the at least one shift groove upon rotation of the transmission shaft.

The problem underlying the invention is solved by the features of the independent claims. Further advantageous embodiments will become apparent from the dependent claims and the drawings. It is proposed a switching device for a transmission, in particular a two-stage planetary gear, having a rotatably formed shift sleeve and at least one stationary trained switching element. The shift sleeve is displaceable for switching the transmission along its axis of rotation in at least one switching position. In this way, a first switching state of the transmission can be generated in which the drive shaft is coupled without translation, stocky and / or translated with the output shaft of the transmission. The shift sleeve has a first connection region in which it can be connected to a drive shaft of the transmission such that a rotational movement of the drive shaft can be transferred to the shift sleeve.

The switching element is preferably a switching pin, which is arranged in particular in the region of the outer circumference of the shift sleeve and / or radially spaced from this. The switching element is positively coupled during its actuation for the axial displacement of the shift sleeve in the switching position with the shift sleeve. Preferably, the switching element, in particular the switching pin, for positively coupling or connecting to the switching sleeve are moved from a radially outer first position in the radial direction into a radially inner second position.

The shift sleeve has a stop in the circumferential direction. The stop is designed such that it is able to strike the actuated switching element, so that the rotational movement of the switching sleeve is stopped relative to a rotational movement of the drive shaft. That is, in the actuated state of the switching element, this comes into contact with the stop of the switching sleeve. As a result, a further rotational movement of the shift sleeve is largely blocked.

In contrast to known technical solutions in which the axial displacement of the shift sleeve via a spiral groove - whereby the shift sleeve is not braked, but still rotatably coupled rotatably coupled to the drive shaft - can be created by means of the stop in the production of a very cost-switching device , Furthermore, the force acting on the switching element can advantageously be reduced by means of the stop. To actuate the switching element thus also a much reduced effort is required. Furthermore, the switching element is advantageously only during Schaltvor- gangs burdened. Suffice a small solenoid for the operation of Schaltelemetes. The switching element is thus preferably an electromagnetic switching pin. Here, the method of the switching pin between the radially outer first position and the radially inner second position is electromagnetically. However, this can also be done by an electric motor, hydraulically or pneumatically or otherwise. By reducing the switching and holding forces acting on the switching device, the switching device can be made very small and inexpensive.

Preferably, the stop in the region of the outer and / or inner circumference of the shift sleeve is formed by a radially extending elevation and / or depression. As a result, a very cost-effective production of the shift sleeve is possible. The stop may thus be groove-shaped (depression) or rail-shaped (elevation) on the outer or inner circumference of the shift sleeve.

In order to be able to ensure a complete stopping of the shift sleeve relative to the further rotating drive shaft, it is advantageous if the stop extends substantially parallel to the axis of rotation. Alternatively, it is also conceivable that the stop is inclined relative to the axis of rotation, so that the shift sleeve slightly twisted when moving in the axial direction. Basically, the stop must be designed such that when the switching element is actuated between the drive shaft and the shift sleeve, a speed difference is effected, wherein the shift sleeve rotates slower than the drive shaft.

It is also advantageous if at one of the two ends of the stop an insertion region for insertion of the actuated switching element and / or at the other end of the stop a Ausführbereich for executing the actuated switching element is arranged. As a result, a reliable stopping and re-driving the shift sleeve can be ensured. To move the shift sleeve, the actuated switching element is thus brought over the insertion in contact with the stop. As soon as the switching element bears against the stop, the switching sleeve is axially displaced along its axis of rotation in the direction of the switching position. In this case, the stop moves along the stationary switching element in the axial direction. As soon as the Shift sleeve has reached the switching position is canceled by means of the execution range of the contact between the contact element and stop, so that the shift sleeve again starts to rotate together with the drive shaft.

It is advantageous if the switching sleeve has a second stop, to which the actuated switching element is able to abut when reversing the direction of rotation of the drive shaft and / or in the switching position located in the switching sleeve. As a result, the shift sleeve can be pushed back from its switching position to its previous starting position. The second stop may also be formed as a in the region of the outer and / or inner circumference of the shift sleeve in the radial direction extending elevation and / or depression.

The shift sleeve can be produced particularly cost-effectively, if the first and / or second stop, preferably with its respective insertion and / or Ausführbereich, is formed by means of a recess. Preferably, the recess is formed on the outer circumference of the shift sleeve. The recess can be advantageously formed in only a single manufacturing step, if this is preferably designed as, in particular Z-shaped, groove. The two opposite flanks of the groove in this case form the first and second stop.

In order to ensure an independent insertion and removal of the switching element in or out of the recess, it is advantageous if the radial depth of the recess in the insertion and / or Ausführbereich starting from the first and / or second stop in the circumferential direction to the level the outer diameter of the shift sleeve is reduced.

The recess can be made very inexpensively, if the bottom of the recess is formed substantially flat over its entire surface.

In order to enable different switching states of the transmission, it is advantageous if the switching sleeve has at least one first recess, by means of which it is displaceable between a first and a second switching position. Additionally or alternatively, it is advantageous if the switching sleeve at least a second Having recess, by means of which it is displaceable between a neutral position and at least one of the two switching positions.

It is also advantageous if the two stops of the first recess in the axial direction of the shift sleeve are designed to be longer than those of the second recess. As a result, advantageously different axial displacement lengths of the shift sleeve can be effected.

It is advantageous if the first connection region is designed such that the stopped shift sleeve moves in the axial direction toward the drive shaft or away from it as a function of the drive shaft rotation direction. In this way, the switching element can be decoupled from the axial forces required for displacing the shift sleeve, since the substantially completely absorbed by the first connection area. The switching element is thus loaded only during the switching process. Advantageously, the switching element can thus be made very small and inexpensive.

It is advantageous if the shift sleeve has a thread, in particular an internal thread and / or fine thread, for axial displacement along the axis of rotation in the connection region. As a result, the first connection region for receiving the axial forces can be formed very inexpensively.

The shift sleeve can be made very space-saving, if the switching device comprises an axially displaceable coupling element for non-rotatably connecting at least two components of the transmission, which is positively and / or non-positively connected to the shift sleeve in a second connection region. The forces occurring when coupling the at least two components of the transmission are thus absorbed by the coupling element, whereby the switching sleeve takes over exclusively the task of switching. As a result, the transmission can be designed to save space.

It is also advantageous if the coupling element with the shift sleeve in the axial direction positively and / or non-positively connected in the circumferential direction. hereby can advantageously be moved to the corresponding shift position and / or neutral position during axial displacement of the shift sleeve at the same time also the coupling element. Furthermore, by means of a non-positive connection in the circumferential direction between the coupling element and the switching sleeve, an undesired axial displacement of the switching sleeve during braking and / or acceleration of the drive shaft can be avoided.

In order to avoid a relative rotation of the shift sleeve relative to the drive shaft in the first connection region during acceleration and / or deceleration of the drive shaft, it is advantageous if in the second connection region, the frictional torque of the circumferentially formed frictional connection between the coupling element and the switching sleeve is greater than that in the first connection region maximum moment of inertia of the shift sleeve.

Furthermore, a switchable planetary gear, in particular for a machine tool, proposed, which has a drive shaft, an output shaft, a planetary arrangement and an axially displaceably mounted central shaft. The central shaft is displaceable by means of a switching device between a first and a second switching position, wherein the central shaft, the drive shaft, the planetary arrangement and / or the output shaft in the two switching positions are different coupled to each other. The switching device is designed according to the preceding description, wherein said features may be present individually or in any combination. Accordingly, the invention may also be a machine tool transmission which has this switchable planetary gear. This is, for example, a machine tool transmission for driving a spindle or another rotatable part of the machine tool.

Further advantages of the invention are described in the following exemplary embodiments. It shows:

1, 1 a is a schematic representation of a switchable planetary gear with a switching device in a first switching state, FIG. 2 shows a perspective detailed view of a switching sleeve of the switching device,

3a-3d show a sequential switching operation of the planetary gear from the first switching state shown in Figure 1 in a second switching state,

FIG. 4 shows a perspective detailed view of the shift sleeve with a second and third recess for displacing the shift sleeve into a neutral position,

Figure 5 shows the planetary gear engaging in the second recess

Switching element for switching the transmission in the neutral state and

Figure 6 shows the planetary gear in neutral position.

Figure 1 shows a schematic representation of a switchable planetary gear. Such planetary gears are preferably used in machine tools, for example for driving a spindle of the machine tool. The planetary gear has a with a drive, not shown, (for example, an electric motor) connectable drive shaft 1, which is rotatably mounted in a housing 28 via corresponding bearings 29. Furthermore, the planetary gear has a rotatably mounted, preferably coaxially with the drive shaft 1 extending, output shaft 2, with the planetary gear with a driven component (for example, a machine tool spindle), which is not shown here, connectable. About the output shaft 2, the rotational movement of the drive to the driven component can be transferred.

Said transmission of the rotational movement takes place by means of a rotatably mounted central shaft 3, which is rotatably coupled on the one hand to the drive shaft 1 and, as explained in more detail below, in different ways with the output shaft 2 in operative connection can be brought to at least a first (see 1) and a second switching state (cf., FIG. 3d) of the planetary gear, in which the speed ratio between the drive shaft 1 and the output shaft 2 is different. Figure 1 shows the first switching state of the planetary gear in which the rotary motion transmission of the drive shaft 1 takes place on the output shaft 2 via an intermediate planetary arrangement 4. The planetary arrangement 4 preferably has a planetary sun 26 rotatably mounted about a rotation axis 27 and surrounded by a plurality of planetary gears 24. The planet gears 24 have external teeth and are supported by means of wheel bolts 25 rotatably mounted in a planet carrier 19 which surrounds the central shaft 3 in an annular manner. Finally, the planetary arrangement 4 preferably comprises a ring gear 23 which is provided with an internal toothing and is rigidly connected to the housing 28, with which the planet gears 24 provided with the corresponding external toothing are meshingly in contact.

As is apparent from Figure 1, the planetary sun 26 of the planetary arrangement 4, designed as an external toothing, first toothing 30 which is rotatably coupled in the first switching state with a formed as an internal toothing second toothing 31 of the central shaft 3. As a result, a rotational movement of the central shaft 3 is transmitted to the planetary sun 26 and from this via the guided in the outer ring gear 23 planetary gears 24 to the planet carrier 19. The planet carrier 19 has a provided with the internal toothing planetary gear, with which it is coupled via a connecting element 21 which is mounted on a roller bearing 1 6 on the central shaft 3 and axially displaceable with this, with a driven shaft gear 17 of the output shaft 2. The connecting element 21 is, in particular, an externally toothed sleeve or a connecting toothed wheel.

In the first switching state shown in FIG. 1, the rotational movement generated by means of a drive is thus first transmitted to the central shaft 3 connected rigidly to the drive shaft 1. From there, the further transmission via the first and second teeth 30, 31 to the planetary sun 26, the rotation causes a movement of the planet gears 24 and thus a rotational movement of the planet carrier 19. The rotation of the planet carrier 19 is finally transmitted by means of the planet carrier gear 20 to the connecting element 21 and from there to the output shaft gear 17, so that as a result a squat drive of the output shaft 2 is ensured. The planet carrier 19 and the planet carrier gearwheel 20 can in particular be executed as a common component, instead of the two separate components shown in Figure 1.

The planetary gear or the planetary arrangement 4 can now be switched from the first switching state shown in Figure 1 in the second switching state shown in Figure 3d. For this purpose, the transmission has a switching device 5. The switching device 5 has a switching sleeve 10, which is designed to be rotatable about the axis of rotation 27. For switching the transmission, the shift sleeve 10 is axially displaceable along its axis of rotation 27. The shift sleeve 10 has a first and a second connection region 6, 7. The first connection region 6 is designed in such a way that the shift sleeve 10 moves in the axial direction towards the drive shaft 1 or away from it as a function of the drive shaft rotational direction as soon as the rotational movement of the shift sleeve 10 is stopped. For this purpose, the switching sleeve 10 in the first connection region 6 a thread 12. The thread 12 is formed, for example, as an internal thread on the inner circumference of the shift sleeve 10. This thread 12 of the shift sleeve 10 is screwed in the first connection region 6 to a corresponding thread 14 of the drive shaft 1. The thread 14 of the drive shaft 1 is formed in the present embodiment as an external thread and arranged on the switching sleeve 10 facing the end of the drive shaft 1.

The switching device 5 further comprises a coupling element 15, by means of which, as already explained above, the central shaft 3 rotatably coupled to the planetary sun 26 via the first and second teeth 30, 31 can be coupled. The coupling element 15 is fixedly connected to the central shaft 3 in the axial and circumferential direction. As a result, a rotational movement of the central shaft 3 and an axial displacement of the central shaft 3 can be transmitted to the coupling element 15. That is, the coupling element 15 follows the movement of the central shaft 3. Alternatively, the coupling element 15 may therefore also be a component of the central shaft 3.

The switching sleeve 10 is connected in its second connection region 7 with the coupling element 15. The connection between the shift sleeve 10 and the coupling element 15 may be formed positively and / or non-positively. Thus, the shift sleeve 10 and the coupling element 15 in the axial direction a positive connection have, so that during the axial displacement of the shift sleeve 10 and the coupling element 15 is moved with the shift sleeve 10. The central shaft 3, the coupling element 15 and the switching sleeve 10 thus form a displaceable in the axial direction of the planetary gear unit. In the circumferential direction of the second connecting portion 7 is formed non-positively. The frictional torque of the frictional connection formed in the circumferential direction between the coupling element 15 and the switching sleeve 10 is greater in the second connection region 7 than the maximum moment of inertia of the switching sleeve 10 occurring in the first connection region 6. This avoids a screw movement between the drive shaft 1 during acceleration or deceleration of the drive shaft 1 and switching sleeve 10 in the first connection region 6 takes place. An axial displacement of the shift sleeve 10 thus takes place exclusively during active braking or stopping by means of a first switching element eighth

This first switching element 8, which is part of the switching device 5, can be seen in FIG. The switching element 8 is arranged with respect to the circumferential direction and axial direction of the switching sleeve 10 fixed to the housing 28. The switching element 8 can be moved to form a positive coupling or connecting with the shift sleeve 10 from the radially outer first position shown in Figure 1 in the radial direction in a radially inner second position (see Figure 3a). It is exemplified in the embodiment shown as a switching pin. The switching element 8 corresponds to a first recess 1 1 of the switching sleeve 10. The first recess 1 1 is formed on the outer circumference 9 of the switching sleeve 10. The recess 1 1 is groove-shaped. Alternatively, it may be formed as a rail and protrude accordingly from the outer circumference 9. An exemplary shape of the recess 1 1 on the outer circumference 9 of the shift sleeve 10 is shown with dashed lines in the region of the central shaft 3 in Figures 1, 3, 5 and 6.

FIG. 1 a shows an enlarged view of the area designated by A in FIG. 1. The frictional connection in the circumferential direction between the shift sleeve 10 and the coupling element 15 is effected in accordance with Figure 1 a by two prestressed spring elements 10A and 10B. These generate a defined frictional torque between the coupling element 15 and the switching sleeve 10. Thus, a type of slip clutch is provided, which upon a rotational movement of the coupling element 15, a braking of the switching sleeve 10 relative to the coupling element 15 is allowed, as soon as a voltage applied to the shift sleeve 10 braking force exceeds the friction torque between coupling element 15 and shift sleeve 10. By providing a relatively high rigidity of the spring elements 10A, 10B, a quasi-positive connection between the switching sleeve 10 and the coupling element 15 can be effected in the axial direction. The shown spring-loaded coupling of shift sleeve 10 and coupling element 15 in the axial direction also helps possible tooth-on-tooth positions between the teeth 30, 31 to dissolve. As spring element 10A, 10B can be used any suitable spring means, for example, one or more disc springs, coil springs or corrugated springs. In alternative embodiments, one or both of the spring elements 10A, 10B may also be omitted. In the latter case, the frictional connection in the circumferential direction between the coupling element 15 and the shift sleeve 10 is then produced otherwise.

Figure 2 shows the switching sleeve 10 with its first recess 1 1 in a detailed view. The first recess 1 1 comprises a first stop 32 to which the actuated first switching element 8 is able to strike for axial displacement of the shift sleeve 10, whereby the rotational movement of the shift sleeve 10 relative to the rotating drive shaft 1 can be stopped. At one of the two ends of the first stopper 32, an insertion portion 34 for inserting the operated first switching element 8 and at the other end of the first stopper 32, a lead-out portion 35 for executing the actuated first switching element 8 is arranged. The internal thread 12 of the switching sleeve 10 at the first connection region 6 (see FIG. 1) is not shown in FIG.

For switching the planetary gear from the first switching state shown in Figure 1 in the second switching state shown in Figure 3d, the first switching element 8 is first actuated according to Figure 3a. As a result, as shown in Figure 3a, the first switching element 8 moves from a radially outer position (see Figure 1) into a radially inner position, whereby it comes into operative connection with the first recess 1 1. Due to the first and / or second connection region 6, 7, the shift sleeve 10 rotates together with the drive shaft 1, the central shaft 3 and the coupling element 15. In particular, the shift sleeve 10 by the frictional connection between the friction sleeve 10 and coupling element 15 in the second connection - area 7 entrained with the rotational movement of the central shaft 3. As a result of this rotational movement of the shift sleeve 10, the first shift element 8, when actuated, passes via the insertion region 34 into the first recess 11. Here, the first switching element 8 abuts on the first stop 32, whereby the rotational movement of the shift sleeve 10 is decelerated or stopped abruptly. On the other hand, the drive shaft 1, the central shaft 3 and the coupling element 15 can continue to rotate due to the slippage of the frictional connection provided in the second connection region 7. Thus, there is now a relative rotation between the switching sleeve 10 and coupling element 15 instead. The frictional torque present between the shift sleeve 10 and the coupling element 15 is supported by the first shift element 8 on the housing 28. Since now the drive shaft 1 rotates and the shift sleeve 10 is stationary, the shift sleeve 10 screws on the axially intermeshing drive shaft 1 due to the intermeshing in the first connection region 6 thread 12, 14. Here, the coupling element 15 is displaced together with the shift sleeve 10 in the direction of the drive shaft 1, since this is coupled in the second connection region 7 in the axial direction positively to the shift sleeve 10.

During this displacement, the first shift element 8 according to FIG. 3b slides along the first stop 32 in the axial direction of the transmission until the shift sleeve 10 according to FIG. 3c has arrived in its second shift position. In this position, the actuated first switching element 8 loses contact with the first stop 32 and slips over the execution area 35 from the first recess 1 1 out. Since the radial depth of the first recess 1 1 in the insertion and / or Ausführbereich 34, 35 decreases from the stop 32 in the circumferential direction to the level of the outer diameter of the shift sleeve 10, the first switching element 8 is pressed radially outwards, so that it again is pushed back into its deactivated starting position.

The planetary gear is now in accordance with Figure 3d in its second switching position. In order to hold the switching device 5 and the switching sleeve 10 in this position, no active switching elements 8, 13 are necessary. Holding the shift sleeve 10 in this position is effected exclusively by means of the first connection region 6, in particular with the screw connection, ie the intermeshing threads 12, 14, between the shift sleeve 10 and drive shaft 1. Vorteilhafter- way, the switching element 8 thus only needs to absorb the force to stop the rotational movement of the shift sleeve 10. The axial displacement of the shift sleeve 10 takes place exclusively in the first connection region 6 through the threaded connection between the shift sleeve 10 and the drive shaft 1.

As FIGURE 3d shows, the connection of first and second toothing 30, 31, which connected the central shaft in its first position (see FIGURE 1) to the planetary sun 26, was released by the axial movement of the central shaft 3, so that the central shaft 3 and the planet sun 26 are now decoupled. Likewise, the connecting element 21 has been moved together with the central shaft 3 in the direction of the drive shaft 1, so that the coupling between the planet carrier gear 20 and the drive shaft gear 17 has been repealed. As a result, thus the output shaft 2 is decoupled from the planetary arrangement 4. In contrast, now takes place by the axial movement of the central shaft 3 in its second position according to Figure 3d, a direct coupling of the central shaft 3 and output shaft 2 by the drive shaft gear 17 was meshingly engaged with the central shaft gear 18. A rotational movement of the drive shaft 1 is now transmitted to the output shaft 2 in this switching state without the planetary arrangement 4 being involved in this case. The inevitable friction losses are thus minimized in this switching state.

To bring the transmission from the second switching state shown in Figure 3d again in the first switching state shown in Figure 1, the direction of rotation of the drive shaft 1 must be reversed. Thereafter, by re-actuation of the first switching element 8, the shift sleeve 10 are displaced in the opposite axial direction such that it moves back from the drive shaft 1 in the first switching position. For this purpose, the activated first switching element 8 according to FIG. 2 passes through an insertion region into the first recess 11. Due to the reversal of the direction of rotation, the lead-in area is now the lead-out area 35 of the first stop 32. The first cut-out 11 also has a second stop 33. As described above, the switching sleeve 10 is stopped in an analogous manner by striking the first switching element 8 on the second stop 33, whereby due to the threaded connection in the first connection region 6, an axial displacement of the sleeve takes place back into the first switching position. As soon as the first shift position is reached is, the actuated first switching element 8 loses the operative contact to the second stop 33 and is led out by a Ausführbereich corresponding to the insertion 34 of the first stop 32 from the first recess 1 1 again, since the shift sleeve 10 due to the frictional connection with the coupling element 15 starts to rotate again. The execution range of the second stop 33 corresponds to the insertion region 34 of the first stop 32. The first recess 1 1 is presently designed as a Z-shaped shift groove.

In addition to the first and second switching position, the planetary gear can also be switched to a neutral position (see Figure 6). For this purpose, the shift sleeve 10 according to Figure 4 optionally have a second recess 22, in which a second switching element 13 can engage. The second switching element 13 may be offset relative to the first switching element 8 axially with respect to the switching sleeve 10 and / or have a greater axial extent than the first switching element 8, for example, by a relation to the first switching element 8 enlarged diameter. This prevents that the second switching element 13 can come into operative connection with the first recess 1 1, for example by it enters the recess 1 1. Accordingly, the dimensions of the switching element 13 and the recess 1 1 are chosen in particular so that an engagement of the switching element 13 is prevented in the recess 1 1. The second recess 22 is arranged and oriented such that the shift sleeve 10 can be moved from the second shift position to the central neutral position. An exemplary shape of the recess 22 on the outer circumference 9 of the shift sleeve 10 is shown with dashed lines in the region of the central shaft 3 in Figures 1, 3, 5 and 6.

Optionally, the shift sleeve 10 has a third recess (not shown in FIG. 4) into which the second shift element 13 can engage. The second and third recesses 22are formed at different ends of the shift sleeve 10. The third recess is oriented and arranged such that the switching sleeve 10 is movable from its first switching position to the neutral position when the second switching element 13 engages therein (ie analogous to the second recess 22, oriented and arranged such that the switching sleeve 10 from their second switching position is movable to the neutral position when the second switching element 13 engages therein). The second and Third recess 22 have, comparable to the first recess 1 1, an insertion region 34, a stop 33 and a delivery region 35. The operating principle of the second and third recess 22 corresponds to that of the first recess 11. The first, second and optionally third recess 1 1, 22 are preferably arranged uniformly on the circumference of the shift sleeve 10. In particular, the second and third recesses 22 or the first and second recesses 1 1, 22 may also be arranged on opposite sides of the shift sleeve 10, so offset by 180 ° in the circumferential direction of the shift sleeve 10 to each other. The first recess 1 1 can also be offset in particular by 90 ° in the circumferential direction of the second or the third recess 22.

Figure 6 shows the neutral position of the planetary gear in which the central shaft 3 assumes a position seen in the axial direction, which lies between its first and its second position and in which it is decoupled from both the drive shaft 1 and the output shaft 2. The axial fixation takes place in this position as well as in the first and second switching position via the first connection region 6 and the second connection region 7. Thus avoids the frictional connection in the circumferential direction between the switching sleeve 10 and the coupling element 15 a screwing or unscrewing the shift sleeve 10th relative to the drive shaft 1, when the drive shaft 1 is braked or accelerated. Furthermore, the screw connection between the shift sleeve 10 and drive shaft 1 holds the shift sleeve 10 in the corresponding neutral position.

The present invention is not limited to the illustrated and described embodiment. Variations within the scope of the claims are also possible as a combination of features, even if they are shown and described in different embodiments. In particular, it is possible to carry out individual or all of the internal gears or internal threads shown in the figures, such as 14, 31, instead as external toothings or external threads, in which case corresponding external toothings or external threads, such as 12, 30, for internal toothings or internal thread. Corresponding internal and external toothing, for example, the 12, 14 could also be replaced by frontal teeth, such as dog clutch teeth.

REFERENCE CHARACTERS

drive shaft

output shaft

central shaft

planetary arrangement

switching device

first connection area

second connection area

first switching element

outer periphery

, switching sleeve

A. spring element

B. spring element

, first recess

, Thread of the shift sleeve

, second switching element

, Thread of the drive shaft

, coupling element

, roller bearing

, Output shaft gear

, Central shaft gear

, planet carrier

, Planet gear carrier

, connecting element

, second recess

, ring gear

, planet

, Studs

, planet sun

, axis of rotation

, casing 29th camp

30th first gearing

31. second gearing

32nd first stop

33rd second stop

34. insertion area

35. Execution area

36th third recess

Claims

claims

1 . Switching device (5) for a transmission, in particular a two-stage planetary gear,

with a rotatably formed shift sleeve (10) which is displaceable in at least one shift position for switching the transmission along its axis of rotation (27), wherein the shift sleeve (10) has a connection region (6) in which it is provided with a drive shaft (1). the transmission is connectable, that a rotational movement of the drive shaft (1) on the shift sleeve (10) is transferable,

and with at least one stationary trained switching element (8) which is positively coupled during its actuation for the axial displacement of the shift sleeve (10) in the switching position with this,

characterized in that

the shift sleeve (10) in the circumferential direction has a stop (32) to which the actuated switching element (8) is able to strike, so that a rotational movement of the shift sleeve (10) relative to a rotational movement of the drive shaft (1) is stopped.

Second switching device (5) according to the preceding claim, characterized in that the stop (32) extends substantially parallel to the axis of rotation (27).

3. Switching device (5) according to one or more of the preceding claims, characterized in that at one of the two ends of the stop (27) has an insertion region (34) for inserting the actuated switching element (8) and / or at the other end of the stop ( 27) has a lead-out area (35) for performing the actuated

Switching element (8) is arranged.

4. Switching device (5) according to one or more of the preceding claims, characterized in that the switching sleeve (10) has a second stop (33) to which the actuated switching element when reversing the direction of rotation of the drive shaft (1) and / or befindlicher in switching position Switching sleeve (10) abuts can, whereby the switching sleeve (10) is pushed back out of its switching position.

5. switching device (5) according to one or more of the preceding claims, characterized in that the first (32) and / or second stop (33), preferably with their respective insertion (34) and / or Ausführbereich (35) by means of a recess (1 1), in particular by means of a groove, preferably a Z-shaped groove, on the outer circumference (9) of the switching sleeve (10) is formed.

6. Switching device (5) according to one or more of the preceding claims, characterized in that the radial depth of the recess (1 1; 22; 36) in the insertion (34) and / or Ausführbereich (35) from the first (32) and / or second stop (33), starting in the circumferential direction, reduced to the level of the outer diameter of the shift sleeve (10).

7. Switching device (5) according to one or more of the preceding claims, characterized in that the switching sleeve (10) has at least one first recess (1 1), by means of which it is displaceable between a first and a second switching position, and / or at least a second recess (22, 36), by means of which it is displaceable between a neutral position and at least one of the two switching positions.

8. Switching device (5) according to one or more of the preceding claims, characterized in that the connecting region (6) is formed such that the stopped shift sleeve (10) in dependence of the drive shaft rotation in the axial direction to the drive shaft (1) back or from this moved away.

9. switching device (5) according to one or more of the preceding claims, characterized in that the switching sleeve (10) for axial displacement along the axis of rotation (27) in the connecting region (6) has a thread (12), in particular an internal thread and / or fine thread , having.

10. Switching device (5) according to one or more of the preceding claims, characterized in that the switching device (5) has an axially displaceable coupling element (15) for non-rotatably connecting at least two components of Transmission comprises, which is positively and / or non-positively connected to the switching sleeve (10) in a second connection region (7).

1 1. Switching device (5) according to one or more of the preceding claims, characterized in that the coupling element (15) with the switching sleeve (10) is positively connected in the axial direction positively and / or circumferentially positively.

12. Switching device (5) according to one or more of the preceding claims, characterized in that in the second connection region (7) the frictional torque of the circumferentially formed frictional connection between coupling element (15) and switching sleeve (10) is greater than that in the first connection region (6 ) maximum occurring moment of inertia of the shift sleeve (10).

13. Switchable planetary gear, in particular for a machine tool, with a drive shaft (1), an output shaft (2), a planetary arrangement (4) and an axially displaceably mounted central shaft (3) by means of a switching device (5) between a first and a the second shaft position is displaceable, wherein the central shaft (3), the drive shaft (1), the planetary assembly (4) and / or the output shaft (2) in the two switch positions are coupled differently, characterized in that the switching device (5) according to a or more of the preceding claims.