Controller cylinder for a transmission

Abstract

The invention relates to a controller cylinder (40) for a transmission, said controller cylinder being designed to push a pawl (14, 50) out of engagement with a shift element part (16) by being rotated on the basis of the gear in order to actuate a shift element of the transmission. The controller cylinder (40) has a cylinder body, a first actuation region (44) for pushing the pawl (14, 50) out of engagement with the shift element part (16) in order to engage a first gear, and a second actuation region (44) for pushing the pawl (14, 50) out of engagement with the shift element part (16) in order to engage a second gear. The first actuation region (44) and the second actuation region (44) have a different shape. The invention additionally relates to an actuation assembly for a transmission, to a transmission, and to a bicycle.

Description

[0001]ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 Shift drum of a transmission The present invention relates to a shift drum of a transmission. The invention also relates to an actuating arrangement for a transmission, a transmission, and a bicycle. Many transmissions are shifted using shift drums. By rotating the shift drum, different shift elements are centrally shifted in order to provide a desired gear. For example, depending on the rotational position of the shift drum, different rotating elements of planetary gear sets of the transmission are connected to one another in a rotationally fixed manner. The rotating movement can release the engagement of a pawl with a shift element part. However, with the same applied drive torque, a different torque can result depending on the gear, which is supported by the engagement of the pawl.As a result, when releasing the clutch, a different actuating torque may be required to rotate the shift drum and thus change gears in the transmission, depending on the gear. This different actuating torque can be unpleasant for the operator and lead to incorrect operation. If the shift drum is rotated by a servo, a different power level may be required depending on the gear. The servo must be designed for the highest load to enable reliable shifting, even if much lower actuating forces are necessary for most gears. As a result, such a servo can be large, heavy, and expensive. A first aspect of the invention relates to a shift drum of a transmission. A transmission can be a device that transmits drive torque from an input to an output. The transmission can, for example, transmit the drive torque from an engine to a tire of a vehicle.The transmission can be designed to provide different, switchable gears for torque transmission. For this purpose, the transmission can, for example, have respective spur gear stages and, alternatively or additionally, respective planetary gear sets. The transmission can, for example, be designed as a bicycle transmission. The transmission can accordingly be designed, for example, as a hub gear or bottom bracket gear. ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 A gear can provide a fixed ratio between an input and an output of the transmission. The shift drum can be a component whose actuation causes a gear change of the transmission. For example, the shift drum can be rotated to actuate different shifting elements. The shift drum can, for example, be used to centrally shift the gears of the transmission in series with a single actuation.A shift element of the transmission can, for example, connect two elements of the transmission, such as rotating elements of a planetary gear set or shafts of a spur gear stage, to one another in a rotationally fixed manner. For example, by actuating a shift element, the shift element can be adjusted between an open and a closed state. In the open state, the shift element cannot transmit any torque, for example. In the closed state, the shift element can, for example, transmit torque. A shift element can, for example, be designed as a positive or frictional clutch. A shift element can function as a brake, by means of which a movable part of the transmission can be locked. The shift drum is designed to press a pawl out of engagement with a shift element part by rotation, depending on the gear, in order to actuate a shift element of the transmission.Gear-dependent can refer to a current gear, a gear change, or even a gear that is being engaged. The shifting element part can, for example, be designed as one half of a clutch of the shifting element. The shifting element part can, for example, rotate at least in certain gears of the transmission when a drive torque is applied. The shifting element part can, for example, be supported on the pawl at least in certain gears and thus be prevented from rotating. The pawl can be designed as a movable part that is pivoted by the action of the shift drum. For this purpose, one end of the pawl can be in contact with the shift drum. Another end of the pawl can be designed to engage with the shifting element part.For example, the pawl can engage in one gear with external teeth on the shift element part, from which the pawl can be pushed by the shift drum to change to another gear. The shift element part ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 has, for example, teeth on its outer circumference for engagement with the pawl. The shift element part can be designed, for example, as a brake ring. The shift drum has a roller body. The roller body can, for example, be made of a metallic material. The roller body can, for example, have a cylindrical basic shape. The shift drum has a first actuating region for pushing the pawl out of engagement with the shift element part to engage a first gear. The shift drum has a second actuating region for pushing the pawl out of engagement with the shift element part to engage a second gear.An actuating region can, for example, protrude from a circumferentially adjacent region of the roller body. An actuating region can, for example, be formed by one side of a cam of the roller body. By rotating the shift drum, an actuating region can, for example, press against the pawl and thus release it from engagement with the shift element part. For example, the first actuating region can come into contact with the pawl at a certain first angular position of the shift drum. The pawl can slide off the first actuating region up to a certain second angular position and thus be pushed away, for example, from a rotational axis of the roller body. At the end of the first actuating region, the engagement of the pawl can then be released and first gear can thus be engaged.For example, the second actuation range can come into contact with the pawl at a specific third angular position of the shift drum. The pawl can slide up to a specific fourth angular position at the second actuation range and thus, for example, be pushed away from a rotational axis of the drum body. At the end of the second actuation range, the engagement of the pawl can then be released and thus second gear can be engaged. Specific rotational angular positions of the shift drum can each correspond to a gear of the transmission. The first angular position and the second angular position can define a first angular position range of the shift drum, which corresponds to a contact of the first actuation range with the pawl. ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30The third angular position and the fourth angular position can define a second angular position range of the shift drum, which corresponds to a contact of the second actuating region with the pawl. The first angular position range and the second angular position range can differ from one another and can also be of different sizes. The first actuating region and the second actuating region can, for example, be spaced apart from one another in the circumferential direction. In both the first and the second gear, the engagement of the pawl with the shift element part can be canceled. In further gears, for example a third gear, the pawl can, however, be in engagement with the shift element part. The first actuating region and the second actuating region have a different shape. For example, the length of the two actuating regions can be different.For example, a gradient and, alternatively or additionally, a curvature of the two actuating areas can be different. For example, a radial distance of a start and, alternatively or additionally, an end of the two actuating areas from a rotational axis of the shift drum can be the same. Accordingly, a position of the pawl after actuation can be essentially the same in first gear and in second gear. The different shapes allow different shift travels to be achieved for first and second gear. This makes it possible to specify an actuating force for each gear. For example, when changing gears where a high load is applied to the pawl for the same drive torque, a long shift travel can be specified and the actuating force can thus be relatively reduced.Conversely, a short shift travel can be specified when changing gears where a low load is applied to the pawl for the same drive torque. This means that the corresponding actuation area can take up little space, which can then be used to reduce the force by means of a large actuation area when high loads are applied in other gears on the shift drum. In this way, a short shift travel can also be achieved there for a short shift time. A further actuation area can be connected to the first and second actuation areas, for example at the apex of a cam. ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 The pawl can slide off at this actuation area when the pawl is brought back into engagement with the shift element part upon further rotation of the shift drum and thus gear change of the transmission.This actuation area can also be used to release the engagement, for example when changing gears in a different direction. Different actuation areas can therefore be used to engage first gear and second gear, depending on whether shifting up or down. These additional actuation areas can all be the same or different in shape. The shift drum can be designed to actuate multiple pawls. The pawls can be arranged axially next to one another. For example, one axial area can be provided for each pawl, each with actuation areas assigned to the corresponding pawl. This allows multiple shifting elements to be actuated for a gear change. For example, the transmission can have two shifting elements, each with an assigned pawl.The pawls can thus be jointly disengaged from an associated shift element part by the shift drum, depending on the gear. The shift drum can also have corresponding actuating regions which are differently shaped for three or more gears. The statements made here regarding the first actuating region and second actuating region, and also regarding just one pawl, apply equally. In one embodiment of the shift drum, it is provided that the two actuating regions are shaped such that, with the same drive torque applied to the transmission, essentially an equally high shifting torque is required to push the pawl out of engagement with the shift element part by rotation of the shift drum when engaging first gear and when engaging second gear. As a result, an essentially equal actuating torque can be required for shifting, regardless of the gear.A shifting torque can be a torque required to rotate the shift drum to engage a corresponding gear with the applied drive torque. The shifting torque can correspond to an actuation torque. For example, shifting travels of different lengths can be distributed on the shift drum so that an almost identical shifting torque is required for each gear. This means that the actuation force can be the same in most driving conditions, allowing shifting to be carried out easily and reliably. When shifting using a servo that rotates the shift drum, for example, the corresponding servo can be particularly compact, lightweight, and cost-effective. The servo therefore no longer has to be designed for a particularly high load in one gear and is therefore no longer oversized for other gears.Especially with bicycles, a crankshaft is often pedaled with approximately the same force even when changing gears, so that such a design can also correspond well to actual use. In one embodiment of the shift drum, it is provided that the first actuation region and the second actuation region are each formed by a partial region of a circumferential surface of the roller body. The circumferential surface can be an outer surface of the roller body which surrounds a longitudinal axis of the roller body. The circumferential surface can, for example, be a lateral surface of the roller body. The longitudinal axis of the roller body can correspond to an axis of rotation of the shift drum when it is actuated to change gears. Differently shaped actuation regions can be manufactured particularly easily on the circumferential surface. The actuation regions can form a flank of a cam on the circumferential surface of the rolling body.In one embodiment of the shift drum, it is provided that the first actuation region is formed by a first ramp on the drum body. Alternatively or additionally, the second actuation region can be formed by a second ramp on the drum body. The first ramp and the second ramp can have different steepnesses. In this way, the actuation regions can be easily adapted to different loads on the pawl and thus to different levels of frictional forces that must be overcome to disengage the pawl at the same drive torque. A ramp can be formed by a flat plane. However, a ramp can also be curved. The steepness of a ramp can be its average or maximum gradient. The steepness can correspond to an increase in the distance of the actuation region from a longitudinal axis of the shift drum per degree of rotation of the shift drum.The steepness can, for example, correspond to an angle relative to a tangent of a circle which intersects the actuating region in the center and has a longitudinal axis of the shift drum as its center. In one embodiment of the shift drum, the drum body is provided with a base material and a surface material. The surface material can form at least one of the two actuating regions. The surface material can also form both actuating regions. Compared to the base material, the surface material can have a lower coefficient of friction with a material of the pawl which contacts the shift drum. As a result, an actuating force for disengaging the pawl can be reduced due to reduced friction between the pawl and shift drum.The surface material can differ from the base material, for example, in terms of a material, a crystal structure, and alternatively or additionally a doping. For example, the surface material can be formed by a coating or by a surface treatment of the base material. By combining surface material and base material, a cost-effective, lightweight, and alternatively or additionally robust material can be selected as the base material, regardless of its friction with the pawl, without resulting in an increased actuating force. In one embodiment of the shift drum, it is provided that at least a partial region of the surface of the drum body is formed by the base material. For example, one of the two actuating regions can be formed by the base material.As a result, even if a ramp length for an equal shifting torque in all gears would otherwise be impermissibly long or short, an equal shifting torque can still be achieved with the same applied drive torque in all gears. Alternatively or additionally, an area of ​​the surface of the roller body, such as an area of ​​the circumferential surface, which does not form an actuation area, can also be formed by the base material. This can, for example, save coating material or limit surface treatment to small areas. ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 A second aspect relates to an actuation arrangement for a transmission. The actuation arrangement has a shift drum according to the first aspect. Respective further features, embodiments, and advantages can be found in the descriptions of the first aspect.Conversely, features, embodiments, and advantages of the second aspect also represent features, embodiments, and advantages of the first aspect. The actuating arrangement has a pivotably mounted pawl. The shift drum of the actuating arrangement is designed to rotate the pawl, depending on the gear, by pivoting it out of engagement with a shift element part in order to actuate a shift element of the transmission. The actuating arrangement can also have the shift element part or the entire shift element. The actuating arrangement can also have multiple pawls, each of which is actuated depending on the gear. In this case, each pawl can be pressed, depending on the gear, by correspondingly assigned actuating regions by pivoting it out of engagement with an associated shift element part due to rotation of the shift drum in order to actuate an associated shift element of the transmission.In one embodiment of the actuating arrangement, it is provided that the actuating device has a servo device designed to rotate the shift drum to actuate the shifting element. The servo device can have a motor by means of which the shift drum can be driven to rotate. The servo device can have a control device to automatically initiate a gear change depending on an operating state, such as a speed of the transmission. The servo device can also be activated manually by a user, for example. The servo device allows for particularly convenient gear changes.The servo device can be configured to rotate the shift drum at different speeds depending on the gear, so that the shift time for engaging first gear and the shift time for engaging second gear are essentially the same. The servo device can thus, for example, compensate for a different ramp length to still achieve consistent shifting behavior. This can be easily achieved with a servo device using a corresponding control system. Alternatively, this can also be achieved using a servo gear between a motor of the servo device and the shift drum.Alternatively or additionally, a manual actuating device can also be designed to rotate the shift drum at different speeds depending on the gear, so that the shift time for engaging first gear and the shift time for engaging second gear are essentially the same. The manual actuating device can, for example, have a gear lever which a driver can press with their thumb to change gear. Depending on the currently selected gear, a transmission ratio for the shift drum can be designed differently in order to rotate the shift drum at different speeds depending on the gear. As a result, the actuating travel of the manual actuating device for changing gears can be essentially the same in each gear, even if the shift drum has to be rotated a different distance depending on the gear.In one embodiment of the actuating arrangement, the pawl has a rotatable roller which rolls at the respective actuating region to push the pawl out of engagement with the switching element part. As a result, friction between the switching drum and pawl can be particularly low, whereby actuating torques can also be particularly low. The roller can, for example, be arranged at an end region of the pawl which faces the switching drum. An opposite region of the pawl can form the engagement region of the pawl with the switching element part. The roller can be arranged in contact with the switching drum, for example with the outer circumferential surface of the drum body. The roller can, for example, be mounted on a rolling bearing. This can further reduce friction and thus the actuating force. The roller can also be formed by the rolling bearing.For example, an outer ring of the rolling bearing forming the roller then rolls on the shift drum. This means that very few parts are required. ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 In one embodiment of the actuating arrangement, it is provided that the pawl is pivotally mounted by means of a rolling bearing. For example, the pawl can be mounted on a bearing housing, which can be formed by a bicycle frame, by means of the rolling bearing. In this way, the respective forces for pivoting the pawl can be particularly low, whereby switching torques can also be particularly low. In one embodiment of the actuating arrangement, it is provided that the pawl is preloaded into engagement with the switching element part. For this purpose, the actuating arrangement can, for example, have a spring element, such as a leg spring.Due to the preload, the pawl can be pressed back into engagement with the shift element part when the shift drum is in a corresponding rotational position. A third aspect relates to a transmission which has the actuating arrangement according to the first aspect and, alternatively or additionally, the shift drum according to the second aspect. Respective further features, embodiments and advantages can be found in the descriptions of the first and second aspects. Conversely, features, embodiments and advantages of the third aspect also represent features, embodiments and advantages of the first or second aspect. The transmission can be designed as a bicycle transmission. For example, the transmission can be designed as a hub gear or bottom bracket gear. The shift drum can be designed as a modular replacement part. This allows for customer-specific adaptation to a number of gears, shift times and maximum possible powershift torques.Thus, a customer-specific shift adaptation can be achieved by exchanging the shift drum, without the rest of the transmission or a servo having to be changed. A fourth aspect relates to a bicycle which has the actuating arrangement according to the first aspect, the shift drum according to the second aspect and, alternatively or additionally, the transmission according to the third aspect. Respective further features, embodiments and advantages can be found in the descriptions of the first, second and third aspects. Conversely, features, embodiments and advantages of the fourth aspect also represent features, embodiments and advantages of the first, second and third aspects, respectively. Fig. 1 schematically illustrates a conventional actuating arrangement for a transmission with a shift drum. Fig.Fig. 2 schematically illustrates a first embodiment of an actuating arrangement for a transmission with a shift drum, in which actuating areas are differently shaped. Fig. 3 schematically illustrates a second embodiment of an actuating arrangement for a transmission with a shift drum, in which actuating areas are differently shaped. Fig. 1 illustrates a conventional actuating arrangement for a bicycle transmission. The actuating arrangement has a shift drum 10 with a drum body, a pawl 14 and a shift element part 16 designed as a brake ring. The pawl 14 is pivotally mounted on a pin 18 and preloaded by means of a spring element 20 into engagement with the shift element part 16.An end region 22 of the pawl 14 facing away from the shift drum 10 engages with a toothing of the shift element part 16 when the shift drum 10 does not push the pawl 14 away from the shift element part 16 and thus out of engagement. This actuation of the pawl 14 occurs depending on the gear by rotation of the shift drum 10 about its longitudinal axis, which corresponds to a central axis of the drum body and extends into the image plane. The drum body has four cam-like elevations 28 on its outer circumferential surface. An end region 24 opposite the end region 22 and facing the shift drum 10 slides along the outer circumferential surface when the shift drum 10 rotates. Upon reaching the cam-like elevation, the pawl 14 is pressed out of engagement with the shift element part 16 by a flank 26 during an exemplary counterclockwise rotation.ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 The cam-like elevations 28 and the flanks 26 are all identically shaped in the actuating arrangement shown in Fig. 1. The shift drum 10 is thus designed symmetrically. To change gears, the shift drum 10 must overcome a frictional force between the end region 22 of the pawl 14 and the contacted tooth flank of the shift element part 16 by releasing the engagement of the pawl 14 with the shift element part 16. This results in a corresponding switching torque for rotating the shift drum 10. With the same applied drive torque, the shift element part 16 is pressed against the pawl 14 with a different torque. This difference results from a gear-dependent different transmission of the drive torque up to the switching element part 16. However, this also results in a different friction force which keeps the pawl 14 in engagement with the switching element part 16.This frictional force must be overcome by the shifting torque for changing gears. Accordingly, despite uniform elevations 28, different shifting torques result depending on the gear, i.e. depending on which cam-like elevation 28 is in contact with the end region 24 of the pawl 14. Fig. 2 schematically illustrates a first embodiment of an actuating arrangement for a transmission with a shift drum 40, in which cam-like elevations 42 are shaped differently. Otherwise, the pawl 14 and the shift element part 16 are of the same design and the function of the actuating arrangement is the same, so that only corresponding differences will be discussed and the same reference numerals are used. Furthermore, in Fig. 2, just as in Fig. 3, the spring element 20 is not shown. In addition, Fig. 2 shows the shift drum 40 in a rotational position in which the pawl 14 has not yet been pushed out of engagement with the shift element part 16.1, however, shows the shift drum 10 in a rotational position in which the pawl 14 has already been pushed out of engagement with the shift element part 16. The shift drum 40 also has four cam-like elevations 42, each of which, upon counterclockwise rotation of the shift drum 40, comes into contact with the end region 24 of the pawl 14 with a flank 44, thus pushing it out of engagement with the shift element part 16. The flanks 44 form respective actuation regions for pushing the pawl 14 out of engagement with the shift element part 16 to engage a corresponding gear of the transmission. However, each of these flanks 44 is shaped as a ramp of varying length and steepness. As a result, a twist angle of the shift drum 40 is distributed asymmetrically over the flanks 44.With a steep flank 44, the shift drum 40 only needs to be rotated through a small angle to actuate the pawl 14 and thus to change gears, whereas with a comparatively flatter flank 44, the shift drum 40 needs to be rotated through a large angle to actuate the pawl 14 and thus to change gears. At the same time, with the comparatively flat flank 44, a lower torque is required to rotate the shift drum 40 to overcome a frictional force at the end region 22 of the pawl 14 than with the steep flank 44—provided the frictional force is the same in both cases. As a result, the cam-like elevations 42 or the flank 44 can be adapted to a ratio of the respective gear, which, with the same drive torque, causes a different load on the switching element part 16 and thus a different frictional force, which counteracts the pressing of the pawl 14 out of engagement with the switching element part 16.Thus, a more uniform switching torque is required for gear changes with the actuating arrangement according to Fig. 2 than with the actuating arrangement according to Fig. 1. In one embodiment, the same switching torque may be required for each gear change with the same drive torque. In the example shown, the shift drum 40 is electrically driven by a servo device. A motor of this servo device is controlled such that the shift drum 40 rotates at different speeds depending on the gear and thus the length of the respective flank 44, which presses against the end region 24 of the pawl 14 during the gear change. The speed is specified such that the switching time for releasing the engagement of the pawl 14 with the switching element part 16 is essentially the same for each gear, despite ramps of different lengths. With long flanks 44, the shift drum 40 rotates quickly, and with short flanks 44 it rotates more slowly in comparison.ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 Fig. 3 schematically illustrates a second embodiment of an actuating arrangement for a transmission with a shift drum 40, in which actuating regions are shaped differently. The actuating arrangement according to Fig. 3 differs from the actuating arrangement according to Fig. 2 only in the design of the pawl 50. The pawl 50 of the actuating arrangement according to Fig. 3 is also pivotally mounted on a pin 18 and has an end region 22 which is designed like the pawl 14 of the first embodiment. The end region 24 of the pawl 50 is formed by an additional roller 52, which in the example shown is designed as a rolling bearing and is mounted on a pin of the pawl 50. With the roller 52, the pawl 50 rolls on the outer peripheral surface of the roller body of the shift drum 40.For this purpose, an outer ring of the rolling bearing forming the roller 52 is in contact with the outer circumferential surface of the roller body of the shift drum 40. As a result, friction between the shift drum 40 and the pawl 50 is lower in the actuating arrangement according to Fig. 3 than in comparison to the actuating arrangement according to Fig. 2. This reduces a switching torque for changing gears or an actuating torque for rotating the shift drum 40. In the examples shown, the shift drum 40 is designed to actuate several pawls 14 and 50, respectively. These are arranged axially along the shift drum 40. Each pawl 14 and 50 is assigned an axial region on which corresponding elevations are formed. Depending on the gear, different ones of the pawls 14 and 50 are pressed out of engagement with a corresponding switching element part 16 in order to actuate different switching elements and to engage corresponding gears in the transmission.ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 Reference number 10 Shift drum 14 Pawl 16 Shift element part 18 Pin 20 Spring element 22 End area 24 End area 26 Flank 28 Elevations 40 Shift drum 42 Elevations 44 Flank 50 Pawl 52 Roller.

Claims

ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 Patent claims 1. Shift drum (40) of a transmission, which is designed to press a pawl (14, 50) out of engagement with a shift element part (16) by rotation, depending on the gear, in order to actuate a shift element of the transmission, wherein the shift drum (40) has a drum body, a first actuating region (44) for pressing the pawl (14, 50) out of engagement with the shift element part (16) to engage a first gear, and a second actuating region (44) for pressing the pawl (14, 50) out of engagement with the shift element part (16) to engage a second gear, wherein the first actuating region (44) and the second actuating region (44) have a different shape.Shift drum (40) according to claim 1, characterized in that the two actuating regions (44) are shaped such that, with the same drive torque applied to the transmission, essentially an equally high shifting torque is required to push the pawl (14, 50) out of engagement with the shift element part (16) by rotating the shift drum (40) when engaging first gear and when engaging second gear.

3. Shift drum (40) according to claim 1 or 2, characterized in that the first actuating region (44) and the second actuating region (44) are each formed by a partial region of a circumferential surface of the drum body. 4.Shift drum (40) according to one of the preceding claims, characterized in that the first actuating region (44) is formed by a first ramp on the drum body and the second actuating region (44) is formed by a second ramp on the drum body, wherein the first ramp and the second ramp have different steepnesses.

5. Shift drum (40) according to one of the preceding claims, characterized in that the drum body has a base material and a surface material, wherein the surface material forms at least one of the two actuating regions. ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 surface, and wherein the surface material, in comparison to the base material, has a lower coefficient of friction with a material of the pawl (14, 50) that contacts the shift drum (40).

6. Shift drum (40) according to claim 5, characterized in that at least a partial region of the surface of the drum body is formed by the base material.

7. Actuating arrangement for a transmission, wherein the actuating arrangement has at least one shift drum (40) according to one of the preceding claims and a pivotably mounted pawl (14, 50), wherein the shift drum (40) is designed to rotate, depending on the gear, to press the pawl (14, 50) out of engagement with a shift element part (16) by pivoting, in order to actuate a shift element of the transmission. 8.Actuating arrangement according to claim 7, characterized in that the actuating device has a servo device which is designed to rotate the shift drum (40) to actuate the shifting element, wherein the servo device is designed to rotate the shift drum (40) at different speeds depending on the gear, so that a shifting time for engaging the first gear and a shifting time for engaging the second gear are essentially the same length.

9. Actuating arrangement according to claim 7 or 8, characterized in that the pawl (50) has a rotatable roller (52) which rolls at the respective actuating region for pressing the pawl (50) out of engagement with the shifting element part (16).

10. Actuating arrangement according to one of claims 7 to 9, characterized in that the pawl (50) is pivotally mounted by means of a rolling bearing. 11.Actuating arrangement according to one of claims 7 to 10, characterized in that the pawl (14, 50) is prestressed to engage with the switching element part (16). ZF Friedrichshafen AG File 213518 Friedrichshafen 2023-01-30 12. A transmission with a shift drum (40) according to one of claims 1 to 6, wherein the shift drum (40) is designed as a modular replacement part.

13. A bicycle with a transmission having the shift drum (40) according to one of claims 1 to 6.

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