Shift drum arrangement and transmission arrangement with such a shift drum arrangement

Abstract

Shift drum arrangement for a shift unit in the drive train of a motor vehicle, comprising: a rotary drive (3) with a motor shaft (4) which can be driven in a first direction of rotation (R1) and in a second direction of rotation (R2), a first shift drum (5) having a first adjusting contour (25) on a first outer circumferential surface for switching a first switching element (56), and a second shift drum (6) having a second adjusting contour (26) on a second outer circumferential surface for switching a second switching element (57), wherein the first adjusting contour (25) and the second adjusting contour (26) are circumferentially closed and are each designed over the circumference in such a way that they have at least a first contour section and a second contour section, which are axially spaced from one another and connected to one another via a gradient section, wherein the first shift drum (5) and the second shift drum (6) are drive-connected to the motor shaft (4) in such a way that, depending on the direction of rotation of the motor shaft (4), one of the shift drums (5, 6) is driven in rotation, while the other shift drum (6, 5) is drive-free, so that the switching of the associated first or second switching element (56, 57) is possible.

Description

The invention relates to a shift roller arrangement for shifting a plurality of shift elements, in particular for a drive train of a motor vehicle, and to a transmission arrangement having such a shift roller arrangement.From DE 195 30 616 A1 a shifting arrangement for a manual transmission is known. The shift arrangement comprises a motor which, depending on the direction of rotation, selectively drives a shift drum or a shift shaft which is accommodated in a locking sleeve in an axially movable manner. The shift shaft has a plurality of members having clutch grooves which can be brought into and out of engagement with the clutch members by rotating the shaft. The actual shifting is accomplished in the shifting arrangement by a separate axial movement of the shifting shaft by means of the actuator.DE 101 28 854 A1 discloses a shifting device for shifting a transmission. In this configuration, a first electric motor is in drive connection with two shift rollers, and can rotate them together. A motor connecting the formwork roller and rotating with the shift roller serves to rotate the two formwork rollers relative to one another. The first motor serves for the normal sequential shifting and the additional motor serves for fine tuning of the rotation of the two shift rollers.DE 10 2016 115 078 A1 discloses a shift drum arrangement having a shift drum with a first shift gate and a shift drum path for actuating at least one shift element of a transmission, and having a blocking device with a blocking gate and with a blocking bolt which engages in the blocking gate. The blocking gate has a labyrinth contour, so that the blocking bolt runs against a stop contour in a direction of rotation of the shift drum and blocks the further rotation of the shift drum. The blocking is released after the shift drum has been partially rotated back in the reverse rotational direction.DE 102 03 633 A1 discloses a shifting device of a transmission with a cam drive which has a shifting element which is rotatably guided on an axis and is provided with at least one groove path. At least one switching means engages in the groove path, which switching means is axially movable accordingly during a rotation of the switching element by the shape of the groove path. The groove path has an upshift path formed as an upshift groove and a downshift path provided for a downshift. The shift-back path is formed as a shift-back groove which guides the switching means into an axial switching position equivalent to a neutral position during a shift-back.WO 2019 / 063227 A1 discloses a motor vehicle transmission having a rotatable shift drum with two grooved tracks. A first grooved track has a front track section, a rear track section and a side section which is designed as a dead end. A track following element engages in the grooved track, which is coupled to a parking lock in such a way that an arrangement of the track following element in the side section causes an engaged state of the parking lock. A second track following element is provided, which engages in the second groove track and is coupled to a shift fork for shifting a forward gear of the motor vehicle.WO 2018 / 141551 A1 discloses a shift drum arrangement for a dual clutch transmission drivetrain. The assembly includes a first shift drum coupled to a first electric motor via a first planetary gear set assembly and a second shift drum coupled to a second electric motor via a second planetary gear set assembly.WO 2015 / 058753 A2 discloses a transmission actuating device with a shift drum.DE 100 11 271 A1 discloses a stepped transmission with a shifting and selecting device with a cam member.Arrangements with shift rollers and shift forks are used, for example, in multi-speed transmissions, wherein the actuation can be carried out manually or electromechanically. A shift drum usually has a circumferential groove on the outer surface, in which one or more shift forks can engage. By rotating the shift drum, the shift forks are moved according to the groove contour, so that the gears are shifted in a predefined order defined by the groove contour. If a plurality of shift elements are to be shifted independently of one another, a separate shift drum with actuator is required for each.It is an object of the present invention to propose a shift drum arrangement which enables the shifting of a plurality of shift elements and has a simple structural design. The object is furthermore to propose a transmission arrangement with such a shift drum arrangement, which is of simple construction.To achieve the object, a shift drum arrangement for a shift unit for a motor vehicle drive train is proposed, comprising: a rotary drive having a motor shaft which can be driven in rotation in a first rotational direction and in a second rotational direction, a first shift drum which has a first setting contour on a first outer circumferential surface for shifting a first shift member, and a second shift drum which has a second setting contour on a second outer circumferential surface for shifting a second shift member, wherein the first setting contour and the second setting contour are closed in a circumferential manner and are each configured over the circumference such that they have at least one first contour section and one second contour section which are spaced apart axially from one another and are connected to one another via a gradient section, wherein the first shift drum and the second shift drum are drive-connected to the motor shaft in such a way, that, depending on the direction of rotation of the motor shaft, one of the shift rollers is driven in rotation, while the other shift roller is free of drive, so that the switching of the associated first or second shift element is made possible.The arrangement enables the switching of two switching systems with independent switching action, with only one rotary drive. The shift systems can be parts of a torque-transmitting shift unit, for example a transmission, a clutch, in particular a disconnection clutch for an optionally drivable drive train, and / or a parking lock. It is possible here for the two shift rollers to be used for actuating the same or different shift units.Within the scope of the present disclosure, any form of torque transmission between the motor shaft and the respective shift drum shaft is intended to be included in a drive-connected manner. In particular, a transmission stage can be provided between the motor shaft and the respective roller shaft, for example a toothed wheel pairing.The rotary drive is configured to rotationally drive the motor shaft in two rotational directions. The rotary drive is preferably designed in the form of an electromechanical servomotor or electric motor, wherein other rotary drives, such as a hydraulic or pneumatic drive, are also possible.The two shift rollers, which can also be referred to as shift drums, are configured separately and can be driven to rotate independently of one another depending on the direction of rotation of the rotary drive. The two shift rollers are in particular drivingly connected to the rotary drive in such a way that, when the motor shaft is driven in the first rotational direction, the first shift roller is driven in rotation while the second shift roller is free of drive, and vice versa, that, when the motor shaft is driven in the opposite second rotational direction, the second shift roller is driven in rotation while the first shift roller is free of drive. Within the scope of the present disclosure, it is also encompassed by the term "drive free" that the associated drive shaft is rotated relative to the shift drum, that is to say that the shift drum is decoupled from the drive shaft in the direction of rotation and can in particular be stationary.Each shift drum can be connected to the motor shaft via an associated freewheel. Such a freewheel is configured such that an input part establishes a torque-transmitting connection with an output part in a first rotational direction, and is freely rotatable with respect to the output part in the opposite rotational direction. In this respect, the freewheel can also be referred to as a freewheel clutch, a one-way clutch or an overrun clutch. The first and second freewheels can in principle be arranged at any desired point in the drive train between the motor shaft and the associated shift drum. The first and second freewheels are configured or arranged among one another such that one freewheel is closed in each direction of rotation of the motor shaft while the other one is open, and vice versa. Thus, the two switching systems can be selectively actuated by a corresponding selection of the direction of rotation. Thus, a servomotor can actuate two switching mechanisms independently of each other.In particular, the first shift drum can be connected to the drive shaft via a first freewheel which locks when driving the motor shaft in the first rotational direction and releases when driving the motor shaft in the second rotational direction, and the second shift drum can be connected to the drive shaft via a second freewheel which locks when driving the motor shaft in the second rotational direction and releases when driving the motor shaft in the first rotational direction.According to a first embodiment, the two shift rollers are arranged on a common drive shaft which is drivingly connected to the motor shaft. According to a second embodiment, the two shift rollers can be arranged on two separate drive shafts, which are both drive-connected to the motor shaft. The two shift drum shafts can be arranged parallel or at an angle to one another. When two shafts are used, the freewheel can also be arranged in the drive train between the servomotor and the selector shaft instead of between the selector drum and the selector drum shaft.Each shift drum has at least one encircling setting contour which can be designed in particular in the form of a guide groove. The adjustment contour is designed over the circumference such that it comprises at least a first contour section and a second contour section, which are spaced apart axially from one another and are connected to one another via a slope section. For each shift drum, at least one shift member, for example a shift fork, can be provided, which interacts with the encircling setting contour. By means of the at least two contour sections, at least two switching positions of the switching element can be realized accordingly.In concrete terms, the first shift drum can have a first setting contour on the first outer circumferential surface for shifting a first shift element, and the second shift drum can have a second setting contour on the second outer circumferential surface for shifting a second shift element.It is understood that any uses for the shift rollers and corresponding configurations of the setting contours are conceivable. For example, one or more adjusting contours can be designed, for example, for shifting at least two gears of a transmission, for actuating a parking lock, for actuating a clutch and / or for locking a differential transmission.Latching means can be provided for at least one of the two shift rollers in order to hold the respective shift roller in a defined rotational position. The latching means can comprise, for example, a latching element which can engage resiliently in a latching recess. For example, the shift drum can have one or more latching recesses distributed over the circumference, in which a latching element connected to a stationary component can engage in a latching manner.According to one embodiment, a sensor can be provided for at least one of the first shift drum and the second shift drum, which is configured to detect a rotational position of the associated shift drum. For this purpose, the shift drum can have one or more encoder elements distributed over the circumference, the positions of which can be detected by the sensor.Preferred embodiments are explained below with reference to the drawing figures. Shown herein: FIG. 1 shows a shift drum arrangement according to the invention for actuating a shift unit for the drive train of a motor vehicle in a first embodiment, partially in longitudinal section; FIG. 2 shows a shift drum of the arrangement from FIG. 1 in an axial view; FIG. 3 shows the circumferential development of the second shift drum of the arrangement from FIG. 1 with the setting contour shown schematically; FIG. 4 shows the circumferential development of the first shift drum of the arrangement from FIG. 1 with the setting contour shown schematically; FIG. 5 shows the circumferential development of a shift drum for the arrangement from FIG. 1 with a schematically drawn-in setting contour in a modified embodiment; FIG. 6 shows a shift drum arrangement according to the invention for actuating a shift unit for the drive train of a motor vehicle in a second embodiment, partially in longitudinal section; and FIG. 7 shows a drive arrangement with a shift drum arrangement according to the invention schematically in a sectional illustration.FIGS. 1 to 4, which will be described together below, show a shift drum arrangement 2 for actuating one or more shift units for the drive train of a motor vehicle (not shown). The shift drum arrangement 2 has a rotary drive 3 and two shift drums 5, 6 which can be driven in rotation by a drive shaft 4 of the rotary drive 3. The rotary drive 3 is configured to rotationally drive the drive shaft 4 in a first rotational direction R 1 and an opposite second rotational direction R 2. The shift rollers 5, 6 are drivingly connected to the drive shaft 4 in such a way that they are driven in rotation depending on the direction of rotation R 1, R 2 of the drive shaft 4, or are free of drive, or are stationary.The shift drum arrangement 2 can be used for shifting various shift units, for example for shifting at least two gears of a transmission, for actuating a parking lock, for actuating a shift clutch and / or for locking a differential transmission. The shift drum arrangement 2 can also be referred to as an actuator arrangement. The rotary drive 3 can be designed, for example, in the form of an electric motor, without being restricted thereto. The drive shaft 4 of the rotary drive 3 can also be referred to as a motor shaft.According to the present embodiment, the two shift rollers 5, 6 are arranged on a common drive shaft 7, which is drivingly connected to the motor shaft 4 and can also be referred to as a shift roller shaft. The drive train 8 between the motor shaft 4 and the shift drum shaft 7 contains an optional transmission stage 9, which is designed to translate a rotational movement of the rotary drive 3 from rapid to slow. It is understood that the transmission of the rotational movement from the rotary drive 3 to the shift rollers 5, 6 can be selected or designed according to the technical requirements. The transmission stage 9 comprises a pinion 10 connected to the motor shaft 4 in a rotationally fixed manner and a gearwheel 11 connected to the shift drum shaft 7 in a rotationally fixed manner, which gearwheel are in toothed engagement with one another.The two shift rollers 5, 6 are configured separately and can be driven to rotate independently of one another depending on the direction of rotation R 1, R 2 of the rotary drive 3. When driving the motor shaft 4 in the first direction of rotation R 1, the first shift drum 5 is driven in rotation, while the second shift drum 6 is free of drive, or free of rotation. When driving the motor shaft 4 in the opposite second direction of rotation R 2, the second shift drum 6 is driven in rotation, while the first shift drum 5 is free of drive or free of rotation. In this context, "drive-free" means, in particular, that the shift drum shaft 7 can rotate relative to the respective shift drum, wherein the shift drum can be stationary.In the present embodiment, the two shift rollers 5, 6 are connected to the shift roller shaft 7 via an associated freewheel 15, 16, respectively. The freewheels 15, 16 in the present embodiment are each configured to act between the shift drum shaft 7 and the respective shift drum 5, 6 in the opposite direction of rotation. When the shift drum shaft 7 is rotated in a first direction of rotation, torque is transmitted to the first shift drum 5 via the first freewheel 15, while the second freewheel 16 is torque-free, so that the second shift drum 6 is stationary. When the shift drum shaft 7 rotates in the opposite direction of rotation, the first freewheel 15 interrupts a torque transmission, so that the first shift drum 5 is stationary, while torque is transmitted to the second shift drum 6 via the second freewheel 16 in order to rotate the latter.The freewheels 15, 16 can be designed in any desired manner in order to achieve the technical functionality-coupling in one rotational direction and decoupling in the opposite rotational direction. For example, a freewheel 15, 16 can each comprise a freewheel input part, a freewheel output part and one or more clamping bodies 14 arranged over the circumference between the input part and the output part. The clamping bodies 14 can be designed, for example, in the form of rollers, non-round bodies or catches. In the present case, the first freewheel output part is formed by a section 13 of the first shift drum 5, and the first freewheel input part is formed by a section 12 of the shift drum shaft 7. Radially between the shaft and the roller, a plurality of clamping bodies 14 are arranged distributed over the circumference. The structure or arrangement of the second freewheel 16 is accordingly between a second freewheel input part, which is formed by a second section 17 of the shift drum shaft, and a section 18 of the second shift drum 6 as output part, between which the clamping bodies 19 are arranged.The shift drum shaft 7 can be mounted rotatably about an axis of rotation A 7 in a stationary component (not shown) via bearing means 21, 22. An axial bearing 23 for decoupling the rotation is provided between the two shift rollers 5, 6, so that the two shift rollers can rotate relative to one another without friction.It can be seen in particular in FIG. 1 that each shift drum 5, 6 has a circumferential setting contour 25, 26, which is designed in the present case in the form of a grooved track, without being restricted thereto. For each shift drum 5, 6, at least one actuator, for example in the form of a shift fork, can be provided corresponding to the number of the setting contours 25, 26, which actuator interacts with the encircling setting contour. For example, the adjusting elements can each be actuated axially via a track follower element which interacts with the adjusting contour. For this purpose, the track follower element engages in the setting contour 25, 26 of the associated shift drum 5, 6 and is moved axially by rotating the shift drum, so that the associated shift fork connected to the track follower element is also axially displaced in accordance with the setting contour 25, 26. It is understood that the adjusting contours can be designed according to the technical requirements for the structural unit to be switched.The exemplary setting contour 25 of the first shift drum 5, which is shown in FIG. 4, is designed to implement three shift positions Pa, Pb, Pc. For this purpose, the setting contour 25 has, over half a rotation of the shift drum 5, that is to say over a rotation angle of 180°, a slope-free first section 25 a, a transition section 25 tconnected thereto with an axial slope, a slope-free middle section 25 b, a second transition section 25 swith an axial slope and a slope-free second section 25 c. The second half of the circumferential extension, i.e. from 180° to 360°, is configured symmetrically to this end, wherein the individual sections 25 s', 25 b', 25 t' are provided with dashed indices. When the track following element engages in the first section 25 a, the first shift position Pa of the shift fork or of the transmission is in contact, which shift position can form, for example, a first gear of the transmission. When the shift drum is rotated through 90° with respect to the shift position Pa, the track follower element moves into the middle shift position Pb, which can form a neutral position of the transmission, for example. During half rotation (180°) of the shift drum 5, the track follower element is in the second shift position Pc, which can form, for example, a second gear of the transmission. Upon further rotation of the shift drum 5, the transmission, starting from the second position Pc, can again first be shifted into the middle or neutral shift position Pb (at 270°) and from there into the starting position (at 360°) or the first shift position Pa, corresponding to the first gear of the transmission. The shift positions Pa, Pb, Pc can also be referred to as shift positions or rotational positions.In order to reliably insert or hold the switching positions Pa, Pb, Pc, latching means 27, 28 can optionally be provided for at least one of the two switching rollers 5, 6. The latching means 27, 28 comprise a latching element 29 in the present case, which can engage latchingly in recesses 30 of the shift rollers 5, 6. In this case, the number of latching recesses 30 preferably corresponds to the shift positions to be assumed in a defined manner. In the present case, four latching recesses 30a, 30b, 30c, 30b' are provided for the first shift drum 5, which recesses are arranged over the circumference in a manner corresponding to the contour sections 25a, 25b, 25c, 25b' and the shift positions Pa, Pb, Pc, respectively. The latching element 29 is designed in the present case in the form of a ball which is loaded radially inward in the direction of the axis of rotation A 7 of the shift drum 5 by a spring 32. The spring 32 can be accommodated or supported in a stationary housing 33.The exemplary setting contour 26 of the second shift drum 6, which is shown in FIG. 3, is designed to implement two shift positions Pa, Pb. For this purpose, the setting contour 26 has, over a full revolution of the shift drum 6, that is to say over 360° about the axis of rotation, a pitch-free first section 26a and a pitch-free second section 26b which is axially spaced apart therefrom and which are connected to an axial pitch via transition sections 26t, 26t'. When the track following element of the second shift drum 6 engages in the first section 26 a, the first shift position Pa of the shift fork or of the shift unit connected thereto is in contact. When the shift drum is rotated by 180° with respect to the first shift position Pa, the track follower element moves into the second shift position Pb, so that the shift fork is displaced into the second shift position Pb. Upon further rotation of the shift drum 6, the first shift position Pa is reached again, and so on.In order to reliably insert or hold the two switching positions Pa, Pb, optional latching means 28 are also provided in the second switching drum 6. In the present case, only two latching recesses 31 a, 31 bare provided for the second shift drum 6, which are arranged over the circumference corresponding to the contour sections 26 a, 26 bor the shift positions Pa, Pb. The latching means 28 for the second contact drum 6 are designed in accordance with the latching means 27 of the first contact drum 5, so that reference is made for brevity to the above description.At least one of the two shift rollers 5, 6 can be provided with a sensor in order to detect the shift position Pa, Pb, Pc or the rotational position of the associated shift roller. For this purpose, the shift drum 5, 6 can have one or more encoder elements distributed over the circumference, the positions of which can be detected by the sensor. The transmitter elements can be arranged in particular in the rotational positions representing the shift positions, so that the engagement of the shift positions can be reliably detected.FIG. 5 shows a further shift drum 5 in developed view for a shift drum arrangement according to the invention with a modified configuration of the setting contour. The shift drum 5 corresponds in terms of construction and functionality in wide parts to the embodiment from FIGS. 1 and 4, so that reference is made to the above description in terms of the common features. Identical or modified details are provided with the same reference numerals as in the above figures. The specific features of the present embodiment will be discussed below.The shift drum 5 according to FIG. 5 has two setting contours 24, 25 which are designed to realize four shift positions Pa, Pb, Pc, Pd. For this purpose, the one setting contour 24 has, over half a rotation of the shift drum 5 (=180° angle of rotation), a slope-free first section 24 a(for the first shift position Pa or the first gear), a transition section 24 tconnected thereto with an axial slope, a slope-free second section 24 b(for the second shift position Pb or the second gear), a second transition section 24 swith an axial slope and a slope-free middle section 24 c(neutral position). The second half of the circumferential extension, i.e. from 180° to 360°, is configured symmetrically to this end.The other setting contour 25 has, via half a rotation of the shift drum 5 (i.e. 180° angle of rotation), a non-inclined axially middle section 25 a(neutral position), a subsequent first transition section 25 twith an axial inclination, a non-inclined first section 25 b(for the third shift position Pc or the third gear), a second transition section 25 swith an axial inclination and a non-inclined second section 25 c(for the fourth shift position Pc or the fourth gear). The second half of the circumferential extension of the setting contour 25, i.e. from 180° to 360°, is configured symmetrically to this end.Each of the two adjusting contours 24, 25 is engaged by an associated track following element. The adjusting contours 24, 25 are matched to one another in such a way that, when the track following element of the adjusting contour 24 runs through the shifting sections 24 aand 24 bor is arranged therein, the track following element of the adjusting contour 25 is located over this angle of rotation range in the section 25 a, that is to say in the neutral position. Accordingly, it is provided in reverse that when the track following element of the adjusting contour 25 runs through the shifting sections 25 band 25 cor is arranged therein, the track following element of the adjusting contour 24 is located over this angle of rotation range in the section 24 c, i.e. in the neutral position.In order to reliably insert or hold the four switching positions Pa, Pb, Pc, Pd, optional latching means 28 can also be provided in the case of the switching drum 5 according to FIG. 5. In the present case, six latching recesses 30a, 30b, 30c, 30d, 30c', 30b' are provided for the shift drum 5, which recesses are arranged over the circumference corresponding to the contour sections 24a, 24b, 25b, 25c or the shift positions Pa, Pb, Pc, Pd.FIG. 6 shows a shift drum arrangement 2 according to the invention in a second embodiment, which corresponds in wide terms to the embodiment according to FIGS. 1 to 4, so that reference is made to the above description with regard to the common features. Identical or mutually corresponding details are provided with identical reference numerals.A difference of the present embodiment according to FIG. 6 is that the two shift rollers 5, 6 are arranged on two separate drive shafts 7, 7'. The two drive shafts 7, 7' are each drivingly connected to the motor shaft 4. The respective drive train 8, 8' between the motor shaft 4 and the shift drum shafts 7, 7' each contains a gear stage 9 in order to translate a rotational movement of the rotary drive 3 from rapid to slow. The first gear stage 9 for the first shift drum 5 comprises the pinion 10 connected to the motor shaft 4 and the gearwheel 11 connected to the shift drum shaft 7, which are in toothed engagement with one another. The second gear stage 9' for the second shift drum 6 comprises the pinion 10 and a second gearwheel 11', which is connected to the second shift drum shaft 7', and which are in toothed engagement with one another. In this case, the two shift drum shafts 7, 7' are arranged parallel in the present case, wherein a different arrangement is also possible.It can also be seen that the first gearwheel 11 and the second gearwheel 11' in the present case have different diameters, so that different transmission ratios for the two shift rollers 5, 6 result. It is understood that the transmission ratios can also be the same, however.In the present embodiment, the freewheels 15, 16 are each arranged between the respective shift drum 5, 6 and the associated shift drum shaft 7, 7'. According to a modified embodiment, however, it is also possible for one or both freewheels 15, 16 to be arranged in the respective drive train 8, 8' between the rotary drive 3 and the shift roller shaft 7, 7'.FIG. 7 shows a transmission arrangement 35 according to the invention with a shift drum arrangement 2 according to the invention according to FIG. 1, The transmission arrangement 35, which in the present case comprises a transmission 36 and a differential transmission 37, can be driven by an electric motor 38. Electric motor 38 and transmission arrangement 35 together form an electric drive for driving a drive axle of a motor vehicle. The electric drive can be used as the sole drive source or with an additional drive source.The motor shaft of the electric motor 38 is connected to the transmission shaft 39. The transmission 36 comprises two shift stages, so that an introduced torque can be transmitted from the transmission shaft 39 to the intermediate shaft 40 with two different transmission ratios i 1, i 2. The intermediate shaft 40 is drivingly connected to the differential carrier 41 of the differential gear 37. By means of the differential gear 37, the torque introduced is divided between two side shafts for driving the vehicle wheels. A clutch unit 42 is provided which can be actuated by the shift drum arrangement 2 in order to shift the transmission 36 selectively into the neutral position, the first gear or the second gear. The shift drum arrangement 2, which is only schematically illustrated here, can be designed, for example, according to FIG. 1 with a shift drum 5, 6 according to FIGS. 3 and 4.The transmission 36 is designed as a reduction gear, so that a rotational movement initiated by the electric motor 38 is translated from rapid to slow. The first transmission stage comprises a first drive wheel 44 rotatably mounted on the drive shaft 39 and a first intermediate wheel 45 connected to the intermediate shaft 40 in a rotationally fixed manner, which are in meshing engagement with one another. First drive wheel 44 and first intermediate wheel 45 form a first wheel set having a first transmission ratio i 1. The second transmission stage comprises a second drive wheel 46 rotatably mounted on the drive shaft 39 and a second intermediate wheel 47 connected in a rotationally fixed manner to the intermediate shaft 40, which are in toothed engagement with one another. Second drive wheel 46 and second intermediate wheel 47 form a second wheel set having a second transmission ratio i2. A third transmission stage comprises the output wheel or intermediate wheel 47 connected to the intermediate shaft 40 and the ring wheel 48 meshing therewith and firmly connected to the differential carrier 41.The differential carrier 41 is rotatably supported in the housing 43 about the rotation axis A 41. The differential gear 37 further comprises a plurality of differential gears 49 rotatably supported in the differential carrier 41 on an axis perpendicular to the rotational axis A41, and two side gears 50, 51 each rotatably disposed coaxially to the rotational axis A41 and meshingly engaged with the differential gears 49. Torque introduced from the ring gear 48 into the differential carrier 41 is transmitted via the differential gears 49 to the two side gears 50, 51, between which there is a balancing action. The sideshaft gears 50, 51 are connected for angular torque transmission by means of constant velocity joints 52, 53 to the associated sideshafts (not shown) which transmit torque to the vehicle wheels.The clutch unit 42 is axially disposed between the first drive gear 44 and the second drive gear 46. The clutch unit is configured to selectively transfer torque from the input shaft to the first drive gear 44 or the second drive gear 46. For this purpose, a coupling element 54 is provided, which can optionally connect a clutch input part connected to the drive shaft 39 in a rotationally fixed manner to the first drive wheel 44 or second drive wheel 46. The coupling element 54 is designed in the form of a sliding sleeve which is held on the clutch input part in a rotationally fixed and axially displaceable manner.The sliding sleeve 54 is actuated via the first shift drum 5 of the shift drum arrangement 2 according to the invention. By actuating the rotary drive 3 in a first rotational direction R 1, the first shift drum 5 is rotated, while the second shift drum 6 is stationary. The track following element 55 interacting with the setting contour 25 follows and moves the shifting element 56 connected thereto, in particular in the form of a shifting fork, in the axial direction. The shift fork 56 engages in an annular groove of the sliding sleeve 54. The shift drum arrangement 2 can be controlled by an electronic controller and can be controlled by the latter as required, depending on current or desired driving states of the motor vehicle.The present transmission assembly 35 includes a two-speed shift formed by a first power path and a functionally parallel second power path. By suitably actuating the shift drum arrangement 2 into the first or second shift position Pb, Pc, the clutch unit 42 can transmit torque selectively via the first power path (wheels 44, 45, 47, 48) or alternatively via the second power path (wheels 46, 47, 48) from the electric motor 38 to the differential gear 37.When the track follower element 55 engages in a central section of the setting contour 25, the shift fork 56 is accordingly in an axially central shift position (N), which corresponds to a neutral position of the shift transmission 36. In this position, the electric motor 38 and the differential gear 37 are decoupled from one another, so that no torque is transmitted between the side shafts and the electric motor 38. When the shift drum 5 is rotated with respect to the shift position Pa, the track follower element 55 travels in a first axial direction (in the present case to the right), so that the shift fork 56, starting from the central position, assumes the first shift position (G1), which corresponds to the first gear of the shift transmission 36. Upon further rotation of the shift drum 5, the track follower element 55 or the shift fork 56 first passes through the axially middle shift position (N) and from there in the second direction (in the present case to the left) into the shift position (G 2) which corresponds to the second gear of the transmission 36. Upon further rotation of the shift drum 5, the track follower element 55 or the shift fork 56 again reaches the axially middle shift position (N) or neutral position.The second shift drum 6, which is only schematically shown in the present case, is rotated in the reverse direction of rotation by actuating the rotary drive 3. The second shift drum 6 serves for shifting a further shift unit, for example a parking lock (not shown).The described embodiments enable the shifting of two shifting systems with independent shifting action, with only one rotary drive 3.Reference numerals denote reference numerals2 Shift drum arrangement 3 Rotary drive 4 Drive shaft / motor shaft 5 First shift drum 6 Second shift drum 7, 7' Drive shaft / shift drum shaft 8, 8' Drive train 9, 9' Transmission stage 10 Pinion 11 Gearwheel 12 Section (15) 13 Section (15) 14 Clamping body (15) 15 First freewheel (5) 16 Second freewheel (6) 17 Section (16) 18 Section (16) 19 Clamping body (16) 21, 21' Bearing means 22, Reference numerals 22' denote bearing means 23 axial bearing 24 setting contour (5) 25 setting contour (5) 26 setting contour (6) 27 latching means 28 latching means 29 latching element 30 latching recess 32 spring 33 housing 35 transmission arrangement 36 transmission 37 differential gear 38 electric motor 39 drive shaft / transmission shaft 40 intermediate shaft 41 differential carrier 42 clutch unit 43 housing 44 first drive wheel 45 first intermediate wheel 46 second drive wheel 47 second intermediate wheel 48 ring wheel 49 differential wheel 50 side shaft wheel 51 side shaft wheel 52 constant velocity joint 53 constant velocity joint 54 clutch element / sliding sleeve 55 track follower element 56 shift element / shift fork 57 shift element A axis P shift position R direction

Claims

Shift drum arrangement for a shift unit in the drive train of a motor vehicle, comprising: a rotary drive (3) having a motor shaft (4) which can be driven in rotation in a first rotational direction (R1) and in a second rotational direction (R2), a first shift drum (5) which has a first setting contour (25) on a first outer circumferential surface for switching a first shift member (56), and a second shift drum (6) which has a second setting contour (26) on a second outer circumferential surface for switching a second shift member (57), wherein the first setting contour (25) and the second setting contour (26) are closed in a circumferential manner and are each configured over the circumference such that they have at least one first contour section and one second contour section which are spaced apart axially from one another and are connected to one another via a gradient section, wherein the first shift drum (5) and the second shift drum (6) are drivingly connected to the motor shaft (4) in such a way that, depending on the direction of rotation of the motor shaft (4), one of the shift drums (5, 6) is driven in rotation, while the other shift drum (6, 5) is free of drive, so that the switching of the associated first or second shift member (56, 57) is made possible.Shift drum arrangement according to Claim 1, characterized in that, when the motor shaft (4) is driven in the first rotational direction (R1), the first shift drum (5) is driven in rotation while the second shift drum (6) is stationary, and in that, when the motor shaft (4) is driven in the second rotational direction (R2), the second shift drum (6) is driven in rotation while the first shift drum (5) is stationary.Shift drum arrangement according to Claim 1 or 2, characterized in that the first shift drum (5) and the second shift drum (6) are arranged on a common drive shaft (7) which is drivingly connected to the motor shaft (4).Shift drum arrangement according to Claim 1 or 2, characterized in that the first shift drum (5) is arranged on a first drive shaft (7) and the second shift drum (6) is arranged on a second drive shaft (7'), the first and second drive shafts (7, 7') being drivingly connected to the motor shaft (4).Shift drum arrangement according to one of Claims 1 to 4, characterized in that the first shift drum (5) is connected to the drive shaft (7) via a first freewheel (15) which blocks when the motor shaft (4) is driven in the first rotational direction (R1) and is open when the motor shaft (4) is driven in the second rotational direction (R2), and in that the second shift drum (6) is connected to the drive shaft (7, 7') via a second freewheel (16) which blocks when the motor shaft (4) is driven in the second rotational direction (R2) and is open when the motor shaft (4) is driven in the first rotational direction (R1).Shift drum arrangement according to one of Claims 1 to 5, characterized in that at least one of the first shift drum (5) and the second shift drum (6) has a latching element (29), with which the respective shift drum (5, 6) can be held in a switching position (Pa, Pb, Pc, Pd, Pe).Shift drum arrangement according to one of Claims 1 to 6, characterized in that a sensor is provided for at least one of the first shift drum (5) and the second shift drum (6), said sensor being designed to detect a rotational position of the associated shift drum (5, 6).Shift drum arrangement according to one of Claims 1 to 7, characterized in that at least one of the first setting contour (25) and the second setting contour (26) is designed for shifting at least two gears of a transmission (36).Shift drum arrangement according to one of Claims 1 to 8, characterized in that at least one of the first setting contour (25) and the second setting contour (26) is designed for actuating a parking lock.Shift drum arrangement according to one of Claims 1 to 9, characterized in that at least one of the first setting contour (25) and the second setting contour (26) is designed for locking a differential gear mechanism (37).Shift drum arrangement according to one of Claims 1 to 10, characterized in that at least one of the first setting contour (25) and the second setting contour (26) is designed for actuating a deactivation clutch.Transmission arrangement with a shift transmission (36) with a clutch unit (42) and a shift drum arrangement (2), in particular for a drive train of a motor vehicle which can be driven by electric motor, wherein the shift transmission (36) can be selectively transferred by means of the shift drum arrangement (2) and the clutch unit (42) into a first shift position in which torque is transferred from an input part to an output part with a first transmission ratio, and into a second shift position in which torque is transferred from the input part to the output part with a second transmission ratio, characterized in that the shift drum arrangement (2) is designed according to one of Claims 1 to 11.Transmission arrangement according to Claim 12, characterized in that the shift transmission (36) can be transferred by means of the shift drum arrangement (2) and the clutch unit (42) into a neutral position in which the input part and the output part are freely rotatable relative to one another.

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