Device and method for changing the center of gravity of a bicycle according to the situation

Abstract

The invention relates to a device (1) for changing the center of gravity of a bicycle, in particular an e-bike, according to the situation, comprising: an actuator (2) for changing the center of gravity of the bicycle, at least one sensor monitoring the bicycle's riding state, a control unit that receives and processes data from the sensor, determines a situation-adapted center of gravity of the bicycle, and outputs corresponding control signals to the actuator to execute the change of the center of gravity. According to the invention, the adjustment speed of the change of the center of gravity is adaptable to the riding state of the bicycle. The invention further relates to a system for changing the center of gravity of a bicycle according to the situation, as well as to a bicycle. The invention also relates to a method for changing the center of gravity of a bicycle according to the situation.

Description

The invention relates to a device for situation-adjusted change of the center of gravity of a bicycle, in particular an electric bicycle, having an actuator for changing the center of gravity, at least one sensor monitoring the driving state of the bicycle, and a control unit which receives data from the sensor, processes said actuator, determines a situation-adjusted center of gravity of the bicycle and outputs corresponding control signals to the actuator in order to carry out the change of the center of gravity.Increasing demands in road traffic result in an increasing need for safety measures, in particular for cyclists. Due to the high center of gravity of the bicycle, which is further promoted by a rider, critical driving situations are the result, for example, during braking. In the case of electric travel edges, the problem is additionally exacerbated by the significantly higher travel speed. At the same time, the comfort requirements increase, since other or further driver target groups are achieved in particular with electric bicycles.Devices and methods for situation-adjusted changes in the center of gravity of an electric bicycle are therefore known from the prior art. However, there is a need to further improve the known devices and methods.It is therefore the object of the invention to provide a device, a system, a bicycle and a method for changing the center of gravity of a bicycle in a situation-related manner, which further increase the safety of the cyclist.The present invention provides an apparatus according to claim 1 which achieves the technical object. Furthermore, the object is achieved by a system according to claim 16, a bicycle according to claim 17 and a method according to claim 18. Advantageous embodiments are the subject of the dependent claims.Specifically, the object is processed by a device for situation-adjusted change of the center of gravity of a bicycle, in particular an electric bicycle, having an actuator for changing the center of gravity, at least one sensor monitoring the driving state of the bicycle, and a control unit which receives data from the sensor, determines a situation-adjusted center of gravity of the bicycle and outputs corresponding control signals to the actuator in order to carry out the change of the center of gravity.According to the invention, an adjusting speed of the change in center of gravity can be adapted to a driving state of the bicycle. In particular in critical driving situations, it is advantageous if the center of gravity of the bicycle changes as quickly as possible in order to increase the safety of the cyclist. Thus, for example, it is advantageous to quickly lower the center of gravity if, for example, safety-critical braking is detected by means of an ABS sensor or a critical inclination of the bicycle is detected.At this point, it should be pointed out that, within the scope of the invention, driving situation is to be understood as meaning not only driving operation but also stationary operation of the bicycle. Furthermore, the general term bicycle is understood to mean single-track muscle-powered bicycles, electric bicycles or pedelecs, but also multi-track load or transport wheels or cargo wheels (muscle-powered or with electric drive).The change in the center of gravity by means of the actuator is preferably effected by adjusting the height of a seat post of the bicycle. By lowering the seat post, it can also be made possible for the rider to stand firmly on the ground with both feet in a standing position. In an non-critical driving mode, on the other hand, a more ergonomically expedient saddle position can be achieved. It is possible to automatically approach these positions according to a suitable preset setting.According to an advantageous embodiment of the invention, the actuator can have at least one drive unit and a transmission unit driven by the drive unit. The drive unit can be operated, for example, in a simple manner by means of an accumulator.Different adjusting speeds of the seat post can be realized in a simple manner if the transmission unit has a shiftable transmission with at least two different transmission ratios, wherein the transmission ratios of the transmission unit can be selected depending on the driving state of the bicycle, such that the adjusting speed of the seat post in the lowering and lifting direction is provided adapted to the driving state of the bicycle.An advantageous embodiment can be achieved if the transmission unit has a free wheel which is dependent on the direction of rotation for adapting the transmission ratio to the driving state of the bicycle. By means of the freewheel, for example, a gear stage can be locked in one direction of rotation and, on the other hand, can be released in the opposite direction, so that a complete transmission ratio of the gear unit is available in the lifting direction and only a lower partial transmission ratio is available in the lowering direction. The adjusting speed in the lowering direction can thus be greatly increased.An electric motor could be used as the drive unit, for example, and a single- or multi-stage planetary gear could be used as the transmission.An alternative advantageous embodiment of the invention provides that the adjusting speed of the seat post is provided by means of a suitable design of the transmission unit and / or the motor characteristic in the lowering and lifting direction adapted to the driving state of the bicycle.Furthermore, a force compensation element can advantageously be provided, which assists an extension movement of the seat post in the lifting direction. In this case, a spring bellows which can be loaded with pressure can be provided as a force compensation element and supports an extension movement of the seat post in the lifting direction. If the seat post has additional spring means, the spring bellows can advantageously also be designed as a pressure accumulator of the spring means.Alternatively, it is conceivable to provide a gas spring element as a force compensation element.In an advantageous development of the invention, the actuator can be designed as an electric spindle drive and can comprise a drive arrangement arranged in a housing with the drive unit and the transmission unit driven by the drive unit, a spindle which can be driven in rotation about an axis of rotation and which is in threaded engagement with a spindle nut in such a way that the spindle nut can be displaced in the axial direction within the housing in a rotationally fixed manner, and a seat tube as an adjusting element for adjusting the height of the seat post, which can be displaced along a displacement axis by means of the drive unit relative to the drive arrangement.Here, the spindle nut can be connected with the adjusting element in a form-fitting manner in such a way that the connection can absorb forces in the pressure direction. The positive connection can be effected in a simple manner by a clip connection, wherein the spindle nut is configured to be produced cost-effectively.To increase the driving comfort, it is provided according to an advantageous embodiment of the invention that the seat post has a seat suspension. Parallelogram spring seat posts are to be mentioned by way of example, which can be adapted, for example, by exchange spring elements.Preferably, a gas force support can be provided for adapting the seat suspension, wherein an axially adjustable adjusting element for gas force support has a pressure chamber which is provided so as to be variably fillable with gas by means of a valve.The mechanical seat suspension can be adapted to the need in a supporting manner by the gas force present in the pressure chamber. By means of the valve, an adaptation of the suspension is possible at all times in a simple manner without removing the seat post. At the same time, the mechanics can be better and permanently protected from external influences such as weathering, rain, dirt, etc., since no replacement is necessary for changing the suspension and the suspension no longer has to be removable with simple means. The individual setting of the suspension can be carried out exclusively via the valve.The pressure chamber can be bounded on a side facing the seat suspension by a piston arranged axially displaceably in the seat tube as a function of a gas volume in the pressure chamber, wherein a plunger arranged on the piston is operatively connected to the mechanical seat suspension in such a way that an axial displacement of the piston brings about a change in the seat suspension. If the mechanical saddle suspension is designed as a parallelogram spring unit with side and support components connected in articulated fashion and a spring element, the spring force can be adjusted to the need by adjusting the joints. A mechanical helical compression spring or a deformable elastomer element are possible as a spring element, for example. As already mentioned, replacement of the spring element is no longer necessary for setting the suspension, and the spring element and the joints can be better and permanently protected from external influences.According to a further advantageous embodiment of the invention, the sensor can be designed as a proximity switch which is designed to sense a contour of a brake disc of the bicycle.In this case, the brake disc can have cams for the form-fit connection to a carrier, and the cams can be designed such that they can be sensed by means of the proximity switch. This allows very fine signal resolution without additional sensor elements. At the same time, proximity switches and brake disk offer a robust and cost-effective system to implement.The object is further achieved by a system for changing the center of gravity of a bicycle, in particular an electric bicycle, in a situation-adjusted manner, having one of the aforementioned devices according to the invention and having an electrically activatable main stand and / or a semi- or fully automated hand brake.Furthermore, the object is achieved by a bicycle with the above-mentioned device according to the invention or with the above-mentioned system according to the invention.Further aspects of the invention relate to a method for changing the center of gravity of a bicycle, in particular an electric bicycle, in a situation-adjusted manner, having the steps:• Acquisition of sensor data representative of the driving state of the bicycle,• evaluating the sensor data and ascertaining a situation-adjusted center of gravity of the bicycle,• generating a control signal for changing the center of gravity of the bicycle,• outputting the control signal to an actuator to execute the change of the center of gravity,• Adaptation of an adjusting speed of the change in center of gravity to a driving state of the bicycle.The change in the center of gravity is preferably effected by adjusting the height of a seat post of the bicycle by means of the actuator. In this case, the height adjustment of the seat post is advantageously carried out more quickly in the lowering direction than in the lifting direction, as a result of which critical driving situations can be mitigated.According to a preferred embodiment, the change of the center of gravity can be effected by means of a device mentioned above.The present invention will be described below with reference to a plurality of exemplary embodiments. Identical or similar components are provided with the same reference sign. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations. Individual or a plurality of exemplary embodiments can therefore advantageously be combined with one another.It represents: FIG. 1 shows a schematic illustration of an actuator for a device according to the invention for situation-adjusted change of the center of gravity of a bicycle, FIG. 2 shows a cross section of the actuator according to FIG. 1 ; FIG. 3 shows a side view of an embodiment of a device according to the invention without a transmission unit of the actuator with sprung seat suspension; FIG. 4 shows a side view of the device according to FIG. 3 without a transmission unit of the actuator with sprung seat suspension; FIG. 5 is a cross-sectional view of the device according to FIG. 4 ; FIG. 6 shows an enlarged detail Q of the cross section according to FIG. 5 ; FIG. 7 shows a cross section of a further embodiment of a device according to the invention; FIG. 8 shows an enlarged detail Q of the cross section according to FIG. 7 and FIG. 9 shows an enlarged detail R of the cross section according to FIG. 7.FIG. 1 shows an actuator 2 of a device 1 for situation-adjusted change of the center of gravity of a bicycle. Within the scope of the invention, a bicycle can be a single-track muscle-powered bicycle, an electric bicycle or a pedelec or a multi-track load, transport or cargo wheel (muscle-powered or with electric drive).In order to increase the safety of a bicycle, the device 1 according to the invention for situation-adjusted change of the center of gravity of a bicycle comprises the actuator 2 for changing the center of gravity, at least one sensor monitoring the driving state of the bicycle, as well as a control unit which receives data from the sensor, processes a situation-adjusted center of gravity of the bicycle and outputs corresponding control signals to the actuator in order to execute the change of the center of gravity.A speed signal could be generated, for example, by scanning a brake disk contour. For this purpose, one or more proximity switches can be used, by means of which spiral arms of the brake disc are scanned.Alternatively, a brake disk made of steel, which is arranged coaxially on a carrier made of aluminum, for example, can have inwardly directed, preferably eighteen, cams for the positive connection to the carrier. These may be sensed by a suitable sensor, such as a proximity switch, to produce a signal for the speed of the bicycle. Additional sensor elements can thereby be omitted, if necessary.In this case, an adjusting speed of the change in the center of gravity is adapted to a driving state of the bicycle, so that the center of gravity of the bicycle can be changed as quickly as possible, in particular in critical driving situations. Thus, for example, it is advantageous to quickly lower the center of gravity if, for example, a safety-critical braking is detected by means of an ABS sensor or a safety-critical inclination of the bicycle is detected by suitable sensors.The change in center of gravity takes place in the exemplary embodiment described by adjusting the height of a seat post 12 of the bicycle, but is not limited thereto. The height adjustment can take place automatically as a function of the driving situation of the bicycle. It is likewise conceivable for a height adjustment to be additionally controlled by the cyclist.By lowering the seat post 12, the rider can also be allowed to stand firmly on the ground with both feet in a standing position. In an non-critical driving mode, on the other hand, a more ergonomically expedient saddle position can be achieved. It is possible to automatically approach these positions according to a suitable preset setting.The actuator 2 has at least one drive unit 3 and a transmission unit 4 driven by the drive unit 3, wherein an electric motor, for example, is used as the drive unit and a single- or multi-stage planetary gear is used as the transmission. In a bicycle with an electric drive, the drive unit 3 can be operated by means of the accumulator of the electric drive.According to the exemplary embodiment shown, the actuator 2 can be designed as an electric spindle drive.As can be seen in particular from FIG. 2, which shows a cross section, the actuator 2 comprises a drive arrangement, arranged in a housing 5, with the drive unit 3 and the transmission unit 4 driven by the drive unit 3, a spindle 6, which can be driven in rotation by the drive unit 3 about an axis of rotation and is in threaded engagement with a spindle nut 7. The spindle nut 7 is provided to be displaceable in a rotationally fixed manner in the axial direction within the housing 5 or a profile tube 8 arranged in the housing 5. The actuator 2 further comprises a seat tube 9 designed as an adjusting element for adjusting the height of the seat post 12, which can be displaced along a displacement axis relative to the drive arrangement by means of the drive unit 3.The profiled tube 8 can preferably be provided from plastic and allows an internal torque support for the axially displaceable spindle nut 7, which is connected to the seat tube 9 in such a way that the connection can absorb forces in the pressure direction. A clip connection that can be produced easily is conceivable. For this purpose, the spindle nut 7 can have elastic spring arms which can be clipped into recesses of the profile tube 8. The spindle nut 7 can also be connected directly to the seat tube 9 via a corresponding connection.On its outer side, the profiled tube 8 has one or more nose-shaped projections 10 which engage in complementary recesses 11 of the housing 5 for the purpose of preventing rotation or transmitting torque. In addition, a further torque-transmitting connection can be effected by partially deforming the housing 5, wherein the material of the housing 5 is pressed into the material of the profiled tube 8. The connection also permits sealing between the profiled tube 8 and the housing 5.In the present exemplary embodiment, the housing 5 forms the fixed part of the seat post that can be fastened in the frame of a bicycle. The adjusting element 9, on the other hand, forms the height-adjustable part of the seat post 12, to which a seat 19 of the bicycle can be fastened. When recognizing a situation in which a change in the center of gravity of the bicycle is advantageous, the drive unit 3 is controlled by the control unit and the seat tube 9 is moved accordingly in the axial direction along the displacement axis, so that the change in the center of gravity can be effected by adjusting the height of the seat post of the bicycle.The height adjustment of the seat post in the lowering direction is faster than in the lifting direction, whereby critical driving situations can be significantly mitigated.The different adjusting speeds of the seat post 12 can be adapted to the driving state of the bicycle, for example, by a suitable design of the transmission unit and / or the characteristic motor curve in the lowering and lifting direction.An alternative embodiment provides for the transmission unit to be designed as a shiftable transmission with at least two different transmission ratios, wherein the transmission ratios of the transmission unit can be selected depending on the driving state of the bicycle, such that the adjusting speed of the seat post 12 in the lowering and lifting direction is provided adapted to the driving state of the bicycle.To adapt the transmission ratio to the driving state of the bicycle, the transmission unit can have, for example, a free wheel that is dependent on the direction of rotation. By means of the freewheel, a gear stage can be locked in one direction of rotation and released in the opposite direction, so that a complete transmission ratio of the gear unit is available in the lifting direction and only a smaller partial transmission ratio is available in the lowering direction. The adjusting speed in the lowering direction can thus be greatly increased.It is likewise conceivable to design the device with a force compensation element which assists an extension movement of the seat post 12 in the lifting direction. In this case, a spring bellows which can be loaded with pressure can be provided as a force compensation element and supports an extension movement of the seat post in the lifting direction. If the seat post 12 has additional spring means, the spring bellows can advantageously also be designed as a pressure accumulator of the spring means. It is likewise conceivable to provide a gas spring element as a force compensation element.The described device can be combined as part of a system for situation-adjusted change of the center of gravity of a bicycle with a main stand that can be activated electrically and / or a semi- or fully automated hand brake.The device 1 can further comprise a mechanical seat suspension 13 shown in FIG. 3, wherein the seat tube 9 is connected to the seat suspension 13. The mechanical seat suspension 13 can be designed as a parallelogram spring seat post with articulated side and support components 14, 15, 16, 17 and a spring element 18. Here, the seat tube 9 is connected to a first support component 16 and a seat 19 of the bicycle is connected to an opposite, second support component 17, wherein the side components 14, 15 are each connected in an articulated manner to the support components 16, 17 to form a parallelogram. The spring element 18, which is designed, for example, as a mechanical helical compression spring, is arranged between two of the parallelogram components 14 to 17 in a known manner in order to provide a suspension. The seat suspension 13 is connected to the seat tube 9 by means of the first support component 16 or by means of a connecting component 20 fastened to the first support component 16.FIG. 3 shows the seat suspension 4 in an rebounded state, in which the two support components 16, 17 have the maximum distance from one another. In a compressed state, which is illustrated for example in FIG. 4, the spring element 19 is compressed, so that the distance between the support components 16, 17 is reduced.The mechanical seat suspension 13 can be designed with a minimum spring force since the device 1 provides gas power assistance as described below. The gas force support is effected parallel to the saddle suspension, whereby an adaptation of the total spring force is possible.FIG. 5 shows a cross section of the device 1 according to FIGS. 3 and 4.For assisting the gas force, a pressure chamber 22 is provided in the seat tube 9, which can be variably filled with gas or air by means of a valve 23. The mechanical seat suspension can be adapted to the need in a supporting manner by the gas force present in the pressure chamber 22. By means of the valve 23, an adaptation of the suspension is possible at all times in a simple manner by means of an air pump without removing the seat post.On a side facing the seat suspension 13, the pressure chamber 22 is delimited by a piston 24 arranged axially displaceably in the seat tube 9.The piston 24 is guided in a sealed manner in the seat tube 9 and has a tappet 25, which likewise extends in a sealed manner through a recess of the connecting component 20. As can be seen from FIG. 5, the tappet 25 protrudes with its free end from the connecting part 20 and is operatively connected to the mechanical suspension 13 via a cam 26, such that an axial displacement of the piston 24 brings about a change in the suspension by an adjustment of the parallelogram components 14 to 17.On the actuator side, the pressure chamber 22 is delimited by a sealing separating piston 27 which is axially displaceable in the seat tube 9 by means of the spindle 6. The sealing is effected, for example, by an O-ring 28 positioned in an annular groove of the separating piston 27 A spindle end 29 facing away from the actuator is in rotatable contact in this embodiment with the separating piston 27 or a projection 30 of the separating piston 27 in order to minimize frictional forces. As can be seen from FIG. 6, the projection 30 is arranged at the bottom of a recess 31 of the separating piston 27, so that additionally a guidance of the spindle end 29 is possible. Here too, the pressure chamber 22 is bounded on the side facing the seat suspension 13 by the piston 24 which is arranged in the seat tube 9 so as to be axially displaceable and the entire piston surface of which is effective. As a result, a relatively high adjusting force can be generated on the plunger 25.Due to the gas present in the pressure chamber 22, the separating piston 27 remains in contact with the spindle 6 and is displaced within the seat tube 9 as a function of the adjusting movement. The gas pressure can thus act on the entire separating piston surface, as a result of which, in addition to the spring force of the saddle suspension 13, a pushing-out force of the actuator is assisted.The size of the pressure chamber 22 is stroke-dependent in this exemplary embodiment, so that the gas force support can be adjusted stroke-dependently.FIGS. 7 to 9 show a further exemplary embodiment. FIG. 7 shows a cross section P-P of a further exemplary embodiment of the device 1. The spindle 6 is rotationally driven about an axis of rotation by the drive unit, not shown, of the drive arrangement and is in threaded engagement with the spindle nut 7, not shown. The spindle nut 7 itself is provided so as to be displaceable in the axial direction within the housing 5 and is connected in a rotationally fixed manner to the seat tube 9, which is displaceable along an adjustment axis relative to the drive arrangement by means of the actuator 2 for adjusting the height of the seat post 12.The connection of the spindle nut 7 to the seat tube 9 is designed in such a way that it can absorb forces in the pressure direction. A clip connection which can be produced easily is conceivable for this purpose, in which the spindle nut 7 has elastic spring arms which can be clipped into recesses of the seat tube 9.The housing, not shown, forms in the present exemplary embodiment the fixed part of the seat post 12 that can be fastened within the framework of a bicycle.For assisting the gas force, the pressure chamber 22 is provided in the seat tube 9, which can be variably filled with air by means of the valve 13. The mechanical seat suspension 13 can be adapted to the need in a supporting manner by the gas force present in the pressure chamber 22. By means of the valve 23, an adaptation of the suspension is possible at all times in a simple manner by means of an air pump without removing the seat post 12.On a side facing the seat suspension 13, the pressure chamber 22 is delimited by the piston 24 arranged in the seat tube 9 so as to be axially displaceable.The piston 24 is guided in a sealed manner in the seat tube 9 and has the tappet 25, which likewise extends in a sealed manner through a recess of the connecting component 20. As can be seen from FIG. 7, the tappet 25 protrudes with its free end from the connecting part 20 and is operatively connected to the mechanical suspension 13 via a cam 26, such that an axial displacement of the piston 24 brings about a change in the suspension by an adjustment of the parallelogram components 14 to 17.On the actuator side, the pressure chamber in the exemplary embodiment shown according to FIGS. 7 to 9 is delimited by a separating tube 32 which surrounds the spindle 6 at least partially and projects into the seat tube 5. The separating tube 32 is substantially pot-shaped and rests with a separating tube end 33 of enlarged cross-section sealingly against the seat tube 9. For this purpose, the seat tube 9 has a radially inwardly pointing shoulder 34, which can be formed, for example, by forming the seat tube material. To seal the separating tube end 33 with respect to the seat tube 9, a disk 35 with a radially extending sealing element 36 can additionally be arranged between the separating tube end 33 and the shoulder 34.This gas force support of this exemplary embodiment is independent of stroke, since in the event of actuator actuation, i.e. in the event of adjustment of the seat tube 9, the separating tube 32 with the seat tube 9 moves along the adjustment axis.From FIG. 8, which shows an enlarged detail Q from FIG. 7, it can be seen that the separating tube 32 is guided with its further end 37 in a guide element 38 in the seat tube 9, wherein the guide element 38 has axially extending recesses 39 on its outer side. Through the recesses 39, the air fed through the valve 23 into the pressure chamber 22 can also pass into an annular chamber 40, which forms the separating tube 32 with the seat tube 9. The pressure chamber 22 thus extends from the piston 24 to the separator tube end 33 and thus offers a large pressure volume and a flat gas force characteristic curve.

Claims

Device (1) for situation-adapted change of the centre of gravity of a bicycle, in particular an electric bicycle, comprising: an actuator (2) for changing the centre of gravity of the bicycle, at least one sensor monitoring the driving state of the bicycle, a control unit which receives data from the sensor, determines a situation-adapted centre of gravity of the bicycle and outputs corresponding control signals to the actuator (2) in order to carry out the change of the centre of gravity, characterized in that an adjusting speed of the change of the centre of gravity is adaptable to a driving state of the bicycle.Device (1) according to claim 1, characterised in that the change in centre of gravity by means of the actuator (2) is effected by adjusting the height of a seat post (12) of the bicycle.Device (1) according to Claim 2, characterized in that the actuator (2) has at least one drive unit (3) and a transmission unit (4) driven by the drive unit.Device (1) according to claim 3, characterised in that the transmission unit (4) has a shiftable transmission with at least two different transmission ratios, wherein the transmission ratios of the transmission unit can be selected depending on the driving state of the bicycle such that the adjusting speed of the seat post (12) in the lowering and lifting direction is provided adapted to the driving state of the bicycle.Device (1) according to claim 4, characterised in that the transmission unit (4) has a free wheel which is dependent on the direction of rotation for adapting the transmission ratio to the driving state of the bicycle.Device (1) according to one of the preceding claims 3 to 5, characterised in that the adjusting speed of the seat post (12) is provided by means of a suitable design of the transmission unit (4) and / or the characteristic motor curve in the lowering and lifting direction is adapted to the driving state of the bicycle.Device (1) according to one of the preceding claims 2 to 6, characterized in that a force compensation element is provided which assists an extension movement of the seat post (12) in the lifting direction.Device (1) according to claim 7, characterised in that a spring bellows which can be loaded with pressure is provided as the force compensation element and assists an extension movement of the seat post (12) in the lifting direction.Device (1) according to claim 8, characterised in that the seat post (12) has additional spring means, wherein the spring bellows is designed as a pressure accumulator of the spring means.Device (1) according to Claim 7, characterized in that a gas spring element is provided as force compensation element, which assists an extension movement of the seat post (12) in the lifting direction.Device (1) according to one of the preceding claims 3 to 10, characterized in that the actuator (2) is designed as an electric spindle drive, comprising: a drive arrangement arranged in a housing (5) with the drive unit (3) and the gear unit (4) driven by the drive unit (3), a spindle (6) which can be driven rotationally by the drive unit (3) about an axis of rotation and is in threaded engagement with a spindle nut (7) in such a way that the spindle nut (7) can be displaced rotationally fixedly in the axial direction within the housing (5), a seat tube (9) as an adjusting element (9) for adjusting the height of the seat post (12), which can be displaced by means of the drive unit (3) relative to the drive arrangement along a displacement axis.Device (1) according to claim 11, characterised in that the spindle nut (7) is connected with the adjusting element (9) in a form-fitting manner in such a way that the connection can absorb forces in the pressure direction.Device (1) according to one of the preceding claims 2 to 12, characterised in that the seat post (12) has a seat suspension (13).Device (1) according to claim 13, characterised in that a gas force support is provided for adapting the saddle suspension (13), wherein an axially adjustable adjusting element (9) for gas force support has a pressure chamber (22), which is provided so as to be variably fillable with gas by means of a valve (23).Device (1) according to one of the preceding claims 1 to 14, characterized in that the sensor is designed as a proximity switch which is designed to sense a contour of a brake disc of the bicycle.System for situation-adapted change of the centre of gravity of a bicycle, in particular an electric bicycle, comprising: a device (1) according to one of the preceding claims, and comprising an electrically activatable main stand and / or a semi- or fully automated hand brake.A bicycle comprising a device (1) according to any one of the preceding claims 1 to 15 or comprising a system according to claim 16.Method for situation-adapted change of the centre of gravity of a bicycle, in particular an electric bicycle, having the steps: • acquisition of sensor data representing the driving state of the bicycle, • evaluation of the sensor data and determination of a situation-adapted centre of gravity of the bicycle, • generation of a control signal for changing the centre of gravity of the bicycle, • output of the control signal to an actuator (2) in order to carry out the change of the centre of gravity, • adaptation of an adjustment speed of the change of the centre of gravity to a driving state of the bicycle.Method according to claim 18, characterised in that the change in the centre of gravity takes place by adjusting the height of a seat post (12) of the bicycle by means of the actuator (2).Method according to claim 19, characterised in that the height adjustment of the seat post (12) takes place more quickly in the lowering direction than in the lifting direction.Method according to one of the preceding claims 18 to 20, characterized in that the change in the centre of gravity is effected by means of a device (1) according to one of the preceding claims 1 to 15.

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