Bottom bracket gear shift device with sensor assembly for an electric bicycle, and electric bicycle comprising such a bottom bracket gear shift device

Abstract

The invention relates to a bottom bracket gear shift device with a sensor assembly (123) for an electric bicycle and to an electric bicycle comprising such a bottom bracket gear shift device with a sensor assembly (123), in particular in the form of a central motor. The bottom bracket gear shift device with a sensor assembly (123), in particular for a muscle-powered vehicle with an electric auxiliary drive, is equipped with a bottom bracket shaft (18) mounted in a gearing mechanism housing (121) and an output shaft (122), wherein the bottom bracket shaft (18) is designed to receive pedal cranks (7), and the output shaft (122) is guided out of the gearing mechanism housing (121). At least one sub-gearing mechanism (74) is located in the gearing mechanism housing (121), and the at least one sub-gearing mechanism (74) has at least one selector shaft (67) on which at least two gear ratios can be set. At least one shaft is directly or indirectly connected to the first of at least two printed circuit boards (44, 45), and at least one housing part of the bottom bracket gear shift device (10) is directly or indirectly connected to the second printed circuit board of the at least two printed circuit boards (44, 45). At least two printed circuit boards are equipped with electronic components (77) which forward at least one signal that represents the torque or the rotational speed being applied to the shaft, and the at least two printed circuit boards (44, 45) are located in the direct vicinity of each other.

Description

[0001] Bottom bracket gearshift with sensor arrangement for an electric bicycle and electric bicycle with such a bottom bracket gearshift

[0002] The invention relates to a bottom bracket gearshift with a sensor arrangement for an electric bicycle and to an electric bicycle with such a bottom bracket gearshift with a sensor arrangement.

[0003] Whenever reference is made to a bottom bracket shifting system with a sensor arrangement in the following description, this also refers to a sensor arrangement for a bottom bracket shifting system. It should be noted at this point that the terms bottom bracket shifting system, bottom bracket gearing, multiple gearing, or gear unit are often used in literature and patent specifications to refer to the same thing.

[0004] Electric bicycles feature an auxiliary drive that assists the cyclist's pedaling motion. A sensor array regulates the auxiliary drive according to the cyclist's desired speed. Gear shifting on an electric bicycle ensures that pedaling can be achieved at a roughly constant cadence over a wide speed range.

[0005] The auxiliary drive on the electric bikes considered here is located near the bottom bracket. In this configuration, derailleur or hub gears are typically used because there isn't enough space at the bottom bracket. However, derailleur systems have a disadvantage in that the components of the gear system—namely, the pinions on the rear hub, at least one chainring, and the chain and derailleur—are unprotected and therefore easily exposed to dirt. Derailleur systems are therefore comparatively maintenance-intensive.

[0006] Hub gears are used instead of, or in conjunction with, derailleur gears on the rear wheel. Hub gears are enclosed in a housing, isolated from the outside environment, and are therefore largely maintenance-free. However, the disadvantage of hub gears is the heavy weight on the rear wheel, which leads to unfavorable weight distribution. The heavy weight on the rear hub is a nuisance not only when carrying the bike, but also when cornering or during aggressive off-road riding.

[0007] A much more advantageous weight distribution results when the gear shift is positioned centrally in the bicycle, as is the case with bottom bracket gears, for example. However, bottom bracket gears are quite large, leaving no space around the bottom bracket for the electric motor. In addition, bottom bracket gears are already so heavy that the additional weight of an auxiliary drive would result in an electric bicycle that would be too heavy for everyday use or for continuing to ride with a flat battery. As early as the 1950s, NSU Quickly bicycles with auxiliary drive and gear shift close to the bottom bracket were being mass-produced. DE967668 is a good example here. This already allowed the rider to adjust their cadence to the riding speed by engaging different gears.

[0008] DE19750659A1 and US2011 / 0120794A1 also disclose a manual transmission with an auxiliary drive, which is located near the bottom bracket. Unfortunately, these designs are relatively large and heavy, which is considered a disadvantage. Another disadvantage of these designs is that changing gears under load without interrupting the pedaling motion is not possible.

[0009] Over the years, bottom bracket gearshifts on bicycles have been continually developed. In terms of size and weight, a transmission design according to EP1445088A2 is advantageous. This is a transmission unit of a human-powered vehicle, with a first shaft, which is usually arranged parallel to the bottom bracket shaft and on which a plurality of loose gears are mounted, and a corresponding number of gears that are mounted on at least one second shaft, wherein the loose gears are each connectable to the first shaft by means of coupling means, wherein the first shaft is designed as a hollow shaft and has one or two coaxially internal shift pins, characterized in that the shift pin(s) is / are connected to drive means designed to axially displace the shift pin(s). The first shaft is also often called the shift shaft.The clutches, often also called shift clutches or shifting devices, are designed as positive-locking freewheels and are mounted on axially movable shift pins. Thus, freewheel bodies are arranged on the shift pins.

[0010] The torque applied by the cyclist to the transmission while riding and during gear shifting must be transferred from the shaft via the clutch to the respective gear. Shifting under load is very difficult with this type of manual transmission, as the axial movement of the clutch becomes increasingly difficult the more torque the rider applies. This is caused by the increased surface pressure between the power-transmitting components.

[0011] The drive mechanism, often also called the actuating mechanism, is no longer able to move the clutch mechanism when shifting under load due to the increased surface pressure. The shifting force is the force that the actuating mechanism must exert to move the clutch mechanism. If the shifting force within a transmission increases depending on the driver's torque, this is considered a major inherent disadvantage.

[0012] State-of-the-art manual transmissions have this inherent disadvantage. According to EP 2 379402 B2, each individual idler gear can be engaged with the selector shaft using a freewheel tooth that is movably arranged on the selector shaft. The freewheel teeth are constantly pressed towards the clutch teeth of the idler gears by springs. The geometry of the freewheel teeth is selected so that they remain reliably engaged in the clutch teeth of the idler gear under load and no reaction force is generated in the direction of the actuating means during operation. The actuating means, which in this design rotates as a camshaft within the selector shaft, must release the relevant freewheel tooth from its positive engagement when shifting under load and in doing so overcome enormous frictional forces.Here, too, the shifting force increases when the user applies increased torque to the bottom bracket spindle via the pedals. This is considered a disadvantage.

[0013] If one considers the patent specification DE 10 2013 112 788 B4 or US10526044B2, the switching behavior under load is indeed improved by an optimized design of the actuating means, but the fact that the frictional forces between the freewheel teeth and the internal toothing of the idler gears must nevertheless be completely overcome by the actuating means is to be considered a disadvantage of this design.

[0014] The actuating mechanism is usually operated by the human hand on the bicycle handlebars. In new, state-of-the-art designs, actuation by electric actuators is also common. Since the human hand and even small electric motors, such as those used in actuators, can only perform a limited amount of mechanical work, there is a need for a bottom bracket shifting system with low shifting forces and improved powershift performance.

[0015] When cycling, the pedals must never slip during gear changes. The cyclist must not suddenly pedal "into the void." This can cause injuries, especially to the knees. Many state-of-the-art transmissions are designed to prevent any freewheeling between individual gears during gear changes.

[0016] As an example, patent DE102004045364.0 is cited here. The clutch means have a freewheel function and can be controlled externally by an actuating means. This bottom bracket transmission is characterized by the fact that the state of at least two clutch means changes simultaneously during the gear shifting process. This allows the change in the state of the clutch means to be controlled during the gear shifting process in such a way that no freewheeling occurs.

[0017] Another example of a good design can be found in patent WO 2009 / 132605 A1. This design also features multiple idler gears mounted side by side on a shaft and connected to the shaft by means of switchable freewheels. To prevent slippage in any situation, there is always a specific period between two gears during the shifting process in which two freewheel bodies are activated and actively pressed into the internal teeth of the idler gears, thus ensuring that one of the two relevant idler gears can transmit torque to the shaft in one direction of rotation.

[0018] Considering prior-art transmissions, such as those described in patent EP 1982913A1, the clutch mechanism is also controlled by the rotation of the actuating mechanism. Since the actuating mechanism is located on a shaft that rotates during travel, the shift command must be transmitted from the stationary housing to the rotating shaft using a superposition gear. If the superposition gear, which is usually designed as a planetary gear, is located coaxially and laterally next to the selector shaft, the overall width of the transmission is disadvantageously increased.

[0019] The Q-factor of a bicycle determines the stance width and indicates the lateral distance between the pedal mounting points and the cranks. If the gear housing exceeds a certain width, the Q-factor becomes too large, which has ergonomic and biomechanical disadvantages.

[0020] Therefore, there is a need for a bottom bracket shifter with a narrow gear housing. If state-of-the-art transmissions are to have a high number of usable gears, two gear stages are often connected in series to achieve this goal.

[0021] Such a structure is clearly visible as an example in Figure 1 in patent US5924950 or in Figure 8 from EP1445088A2. In this case, these transmissions have several actuating means that must be controlled simultaneously by the user in the case of certain gear changes. The need for the bicycle user to operate the actuating means twice is disadvantageous. The user only wants to trigger one operating command in order to change from one gear to another. To implement this function, so-called step-by-step transmissions are known to those skilled in the art. Here, for example, a mechanical input movement is divided into two output movements with different cycle times. A particularly space-saving axial step-by-step transmission from Siemens is known, for example, from patent DE1113618.

[0022] Transmissions that simultaneously control multiple actuating means and clutch means using step-by-step gears are known, for example, from patents FR2776613A1, DE102009060484B4, or DE000019720794A1. However, in these designs, only a limited amount of space is usually available for the step-by-step gear, meaning that only a limited switching force can be transmitted.

[0023] To achieve powershift capability, high shifting force is required. Consequently, a bottom bracket shifting system with sufficient space for a superposition gear and a step-shifting gear is required so that these gears can also transmit high shifting forces when shifting under load. However, the overall installation space of the bottom bracket shifting system should also be as small as possible rearward of the rear wheel to ensure sufficient space for the tires, a short chainstay length, and sufficient space for pivot points for optimal suspension kinematics.

[0024] In summary, there is a need for a bottom bracket shifting system for an electric bicycle that is small and narrow enough to be combined with an auxiliary drive at the bottom bracket, is lightweight, and compatible with modern suspension designs. Additionally, there is a need for a bottom bracket shifting system with improved powershifting performance, yet one that does not allow pedal slippage in any riding or shifting situation. Shifting forces should be reduced compared to the current state of the art.

[0025] State-of-the-art electric bicycles without bottom bracket gears have sufficient space within their housing to accommodate a torque sensor and a speed sensor. The sum of all sensors and electronic components used within an electric bicycle with auxiliary drive, particularly in the form of a mid-drive motor, to generate signals required to control or regulate the motor in the manner desired by the user are referred to below as the sensor assembly.

[0026] To solve the above-described problems of integrating an advantageous bottom bracket gearshift into an electric bicycle with auxiliary drive, especially in the form of a mid-drive motor, a very small and narrow sensor arrangement is required, as well as a novel design and positioning of the components required for a bottom bracket gearshift, which must be redesigned with the above-mentioned properties. In addition, a very narrow sensor arrangement is required because a certain amount of space is also required for the actuation and clutch devices that function under load.

[0027] The invention solves this problem by means of a bottom bracket gearshift as defined in claim 1. It provides a bottom bracket gearshift with a sensor arrangement, in particular for a human-powered vehicle with an electric auxiliary drive, with a bottom bracket shaft and output shaft mounted in a gear housing, wherein the bottom bracket shaft can be designed to accommodate pedal cranks and wherein the output shaft preferably extends out of the gear housing, and wherein at least one partial gearshift is located in the gear housing, wherein the at least first partial gearshift has at least one selector shaft on which at least two gear stages can be set. This design is very advantageous because it allows an additional gearshift to be integrated into the drive system, also referred to as a mid-engine. This integrated gearshift has a much longer service life than the derailleur gearshifts that are common and frequently used today.A shaft is directly or indirectly connected to the first of at least two circuit boards, and preferably at least one housing part of the bottom bracket gearshift is directly or indirectly connected to the second of at least two circuit boards. In this embodiment, components from the bottom bracket gearshift can be used to construct the sensor arrangement. This is advantageous for optimal use of the installation space. If the at least two circuit boards that form part of the sensor arrangement contain electronic components that transmit at least one signal that is representative of the torque or speed applied to the shaft, and if the at least two circuit boards are located in close proximity to one another, the sensor arrangement can be constructed very narrowly and can be advantageously integrated into the bottom bracket gearshift. Externally mounted sensors are advantageously eliminated.

[0028] The invention can be further improved by the additional embodiments described below. The individual embodiments are advantageous independently of one another and can be combined with one another as desired.

[0029] If the bottom bracket shifter is preferably designed such that the surface of at least one circuit board on which the electronic components are located is perpendicular to the rotational axis of the shaft, then axial space can be saved. This saving of axial space within the bottom bracket shifter leads to an improved Q-factor and can be further improved if the surfaces of the at least two circuit boards on which electronic components are located are arranged coplanar with each other.

[0030] If, in a preferred embodiment, not only one shaft of the bottom bracket gearshift, but the bottom bracket shaft is connected directly or indirectly to the first of the at least two plates, more installation space will be available on other shafts within the bottom bracket gearshift, for example on the shift shaft, for an advantageous design of the shifting operation.

[0031] In a preferred and advantageous embodiment, the sensor arrangement can be constructed very narrowly if the bottom bracket shifting system is characterized in that the bottom bracket spindle is directly or indirectly connected to a hollow input shaft located coaxially with the bottom bracket spindle, wherein the hollow input shaft is preferably coaxially connected to at least two drive gears, and wherein the first of at least two plates is attached to a drive gear or the hollow input shaft. The use of such a hollow input shaft is advantageous because this hollow input shaft can be designed to be torsionally soft. Defined torsional softness leads to an improved sensor signal, since larger displacements can be sensed.

[0032] If a freewheel is arranged between the bottom bracket spindle and the input hollow shaft, the available installation space is used well, the mass of the structure is reduced and the freewheel prevents the electric auxiliary drive from driving the cyclist's legs, which can be considered an advantageous safety feature.

[0033] If the bottom bracket shifting system with the sensor arrangement is designed in such a way that the first circuit board exchanges signals with the second circuit board wirelessly, wear that would otherwise occur if mechanical signal transmission methods such as slip rings were used is reduced.

[0034] The electronic components on the circuit board, which rotates with the bottom bracket spindle, require electrical power. If the innovation is preferably characterized by inductively transferring electrical power from the circuit board, which is connected to a housing part, to the circuit board, wear that would otherwise occur with mechanical transmission methods such as slip rings is reduced. A shift shaft always has an actuating device, which usually has to be placed to the side of the shift shaft. The additional attachment of the sensor assembly to the shift shaft is disadvantageous, as this arrangement would require a wide design.In a preferred embodiment, there is usually installation space available to the right and left of the hollow input shaft and hollow output shaft if the gears arranged on the hollow input shaft and hollow output shaft have a tip diameter that is at least 1.5 times the diameter of the hollow input shaft or the hollow output shaft. In this case, the torsionally soft shaft section can be placed under the gears. For this purpose, the bottom bracket gearshift preferably has a hollow output shaft to which a belt pulley or a chain wheel for a traction device reaching a rear wheel of the electric bicycle can be attached, and wherein the bottom bracket shaft runs coaxially in the hollow output shaft and wherein the at least two plates are arranged axially to the right or left of the hollow output shaft. For this purpose, at least one plate preferably has a bore or an open pocket that is almost coaxial with the hollow output shaft.

[0035] Preferably, the input hollow shaft and the output hollow shaft are arranged next to each other on the bottom bracket shaft, wherein the at least two plates are arranged centrally between the input hollow shaft and the output hollow shaft, since in this way the fixed one of the two plates can be attached very easily and cost-effectively in the housing.

[0036] If the housing in which the gearbox and the bottom bracket spindle are accommodated is designed to accommodate the electric auxiliary drive and / or the actuation assembly and / or the electric drive assembly, wherein only one of the at least two circuit boards is firmly connected to the housing, the housing can be made narrow and light.

[0037] Seals such as shaft seals and additional chambers in the housing are advantageously eliminated if the bottom bracket shifting system is characterized by the fact that the at least two circuit boards are housed in the part of the housing where the gearbox runs in an oil bath. For this purpose, the circuit boards are designed so that the lubricating oil does not impair the electrical and electronic functions.

[0038] In addition, the overall width of the bottom bracket shifter is further reduced if the surfaces of the at least two circuit boards containing electronic components are only a maximum of eight millimeters apart. If, in a preferred design of the bottom bracket shifter, the at least two circuit boards rotate relative to each other during operation and never touch each other, wear can be advantageously reduced.

[0039] A bottom bracket gearshift with a first partial transmission and a second partial transmission, which are connected in series for power transmission, wherein the first partial transmission and the second partial transmission have a selector shaft on which a plurality of idler gears are mounted, which form gear pairs of the respective partial transmission with a corresponding plurality of drive gears and output gears, wherein the idler gears can be connected to the selector shaft by means of coupling means, is advantageous in combination with the novel sensor arrangement, since in this way a particularly compact drive system with a large number of gear stages is created.

[0040] If the novel bottom bracket gearshift is preferably characterized in that the at least two plates are located centrally between the first partial gearshift and the second partial gearshift, a particularly narrow and light drive system can be created.

[0041] If the bottom bracket shifting system with sensor arrangement is characterized in a preferred embodiment by the bottom bracket shifting system having an auxiliary electric drive, wherein a power flow from the auxiliary electric drive and a power flow from the bottom bracket spindle are superimposed before or within the first partial transmission or before or within the second partial transmission, and wherein at least one of the at least two circuit boards uses a sensor to determine a signal that represents at least part of the power flow, then mechanical components can advantageously be used for the transmission and simultaneously for the sensor arrangement. This saves costs and weight.

[0042] If, in a preferred embodiment, components are arranged within the bottom bracket gearshift on the second circuit board, which is directly or indirectly connected to the housing, which carry the signal that is representative of the torque or the speed out of the housing, then only a few electronic components on this circuit board need to be designed to be oil-resistant.

[0043] To simplify the design, it is preferable if the signals representative of torque or speed within the bottom bracket shifting system are routed via one or more cables. The cables are routed through an opening in the housing. The housing opening, with its cable entry, is designed to prevent oil from penetrating through it. This simplification is achieved primarily because only a few electronic components on the two circuit boards need to be oil-resistant, and a wired connection is more cost-effective than a wireless connection.

[0044] To keep the weight of the bottom bracket gear system as low as possible, at least two of the drive gears are made from a single piece.

[0045] A further weight saving can be achieved preferably within the bottom bracket gear system if at least two of the output gears are made from one piece.

[0046] The invention is explained below by way of example with reference to the accompanying drawings using exemplary embodiments. In accordance with the above embodiments, individual features may be omitted if the technical effect of a feature is not important for a specific application. Conversely, a feature not described or illustrated in an exemplary embodiment may be added if the technical effect of this feature is important for a specific application.

[0047] In the drawings, the same reference numerals are used for elements that correspond to one another in terms of structure and / or function.

[0048] They show:

[0049] Fig. 1 A side view of an electric bicycle with bottom bracket gears in a first embodiment.

[0050] Fig. 2 A perspective view of the bottom bracket gearshift from Figure 1 from the rear left.

[0051] Fig. 3 A side view of the bottom bracket gearshift from the right.

[0052] Fig. 4 A sectional view through the plane spanned by the rotation axis of the bottom bracket spindle and the rotation axis of the shift shaft.

[0053] Fig. 5 A cross section through the plane AB of Figure 4.

[0054] Fig. 6 A perspective view of the bottom bracket gearshift from Figure 2 without the housing.

[0055] Fig. 7 A perspective view of the shift shaft assembly

[0056] Fig. 8 Sections through a bottom bracket gearshift idler gear, viewed from the left, in different states. Fig. 9 Schematic representations of the shifting states from Figure 8.

[0057] Fig. 10 Schematic representation of the coupling agent in comparison to the state of the art.

[0058] Fig. 11 The selector shaft and the clutch means in a detailed perspective view.

[0059] Fig. 12 A section through the operating gear of the shift shaft of the bottom bracket gearshift.

[0060] Fig. 13 A section through the step-by-step gearing of the bottom bracket shift shaft.

[0061] Fig. 14 A schematic representation of the right end of the selector shaft and all actuating means.

[0062] Figure 1 shows a side view of an electric bicycle with bottom bracket gears in a first embodiment. In an advantageous embodiment, the electric drive motor is also integrated into the bottom bracket gears. The frame 1 is assembled from a top tube 2, a down tube 3, and a seat tube 4. The battery 5 is integrated around the down tube 3. At the lower end of the seat tube 4 and the down tube 3 is a bracket 9 into which the bottom bracket gears 10 are screwed. The rear wheel 13 is attached to a swing arm 14 and rotates about the rotation axis 19. The vehicle has a front wheel suspension 15 and a rear wheel suspension 16. The cyclist feeds their mechanical power into the crank arms 7 via the pedals 6. The human drive power is fed into the bottom bracket gears 10 via the crank arms 7.The gear ratio, selected by the user via a control element 11 on the handlebar 12, is regulated within the bottom bracket shifting system 10. Additional power is added to the pedaling power applied by the user within the bottom bracket shifting system 10. This additional power is provided by an electric motor. This illustration in Figure 1 is only an example. The bottom bracket shifting system 10 can be designed with or without an auxiliary drive. The output shaft of the bottom bracket shifting system is coaxial with the bottom bracket shaft and carries the front pulley 8. The front pulley 12 thus forms the transmission output. It rotates at different speeds relative to the crank arms 7, depending on which gear has been engaged by the vehicle user. In this embodiment, the mechanical power is transmitted to the rear wheel 13 via a belt 12.Optionally, such transmission of power to the rear wheel 13 can also take place via any other type of transmission.

[0063] Figure 2 shows a perspective view of the bottom bracket gearshift 10 from Figure 1 from the rear left. The pedals 6 and the crank arms 7 are not shown. The frame is cut away and partially shows the down tube 3 and the seat tube 4. At the lower end of the seat tube 4 and the down tube 3 is a bracket 9 into which the bottom bracket gearshift 10 is screwed. The swing arm 14 is also cut away. In an advantageous embodiment, the swing arm 14 is attached to the bracket 9 via a swing arm bearing 17. Anti-squat is a device on wheeled vehicles that is intended to prevent or reduce the "dive" during acceleration and thus a pitching movement of the body backwards due to the dynamic wheel load transfer. It is also referred to as pitch compensation.In order to achieve good anti-squat behavior on bicycles, a position of the swing arm bearing 17 close to the bottom bracket spindle 18, usually above and slightly behind the bottom bracket spindle 18, is advantageous. In addition, it is advantageous for the geometry and the resulting handling of the bicycle if the distance from the bottom bracket spindle 18 to the axis of rotation of the rear wheel 19 is as small as possible. The output shaft of the bottom bracket gear system is located invisibly on the right-hand side of the vehicle, coaxial with the bottom bracket spindle 18, and carries the front pulley 8. The front pulley 12 thus forms the transmission output. The mechanical power is transmitted to the rear wheel via a belt 12. The belt tensioner 20 is attached to the housing 22 of the bottom bracket gear system 10 via fastening plates 21.The tension pulley 23 is a component of the belt tensioner 20 and ensures correct belt tension in the belt 12, regardless of the position of the rear wheel 13 due to the suspension 16. The bottom bracket derailleur has a left protective cap 24 that protects the bottom bracket derailleur from environmental influences. Another left protective cap 24 is located in front of the shift shaft (not visible here). In an advantageous embodiment, the bottom bracket derailleur features fixed bearing axes that are connected to the housing 22 by means of fastening screws 25.If one considers a vertical plane A, which runs through the rotational axis of the bottom bracket spindle and is perpendicular to the road surface, the advantageous design of the new feature becomes apparent: All transmission shafts are located in front of this plane, allowing sufficient tire clearance and enough space for a technologically advantageous position of the swing arm bearing 17, combined with an advantageous positioning of the sensor arrangement near the bottom bracket spindle. The belt tensioner 20 is designed so that its tensioning pulley can be located to the right of the tire and its housing in front of the tire.

[0064] Figure 3 shows a side view of the bottom bracket gearshift 10 from the right. Here, too, the illustration shows an example of an advantageous embodiment of the bottom bracket gearshift with an integrated electric drive motor and electric gearshift actuation for bicycles with electric auxiliary drive. The belt 12, the pedals 6, and the crank arms 7 are not shown in this illustration. The bottom bracket gearshift 10 in this embodiment can be disassembled into three assemblies, which are housed in a common multi-part housing and are described in more detail below. The installation space for each assembly is outlined in dashed lines in Figure 3. The gearshift assembly 84 includes, in addition to the individual gear stages, the clutch and the connection to the actuating means, as well as the innovative sensor arrangement with the electronic components responsible for determining the torque and speed at the bottom bracket shaft 18.The rotational axis X1 of the bottom bracket shaft 18 and the rotational axis X2 of the selector shaft 67 are located at the center of this gearbox assembly 84. The right-hand gearbox housing 34, from which the output shaft 30 and the hollow output shaft 36 emerge, is visible. The pulley 8 is bolted to the output shaft 30 using six fastening screws 82. The output shaft 30 is connected to the hollow output shaft 36 via a spline 73 and is axially secured using a shaft nut 29. The electric drive assembly 83 is located in front of the gearbox assembly 84 in the direction of travel. The shaft of the electric motor rotates around the rotational axis of the electric motor X3. The actuation assembly 85 is arranged below and on the right side of the gearbox assembly 84. Within the actuation assembly 85 there is the stepping gear, superposition gear as well as the electrically operated actuator and an actuator gear and a sensor system.The right-hand gearbox housing 34 is partially filled with oil to lubricate the gears and is closed by the right-hand side cover 81. The sensors and processing electronics, which determine the speed and position of the electric motor, the actuator motor, and the gearbox actuation, are located in another chamber, which is closed by the right-hand outer cover 86. This exemplary gearbox housing design is particularly space-saving and thus ensures a narrow Q-factor and low weight.

[0065] Figure 4 shows a sectional view through the plane spanned by the rotational axis X1 of the bottom bracket spindle 18 and the rotational axis X2 of the shift shaft 67. The area of ​​the electric drive assembly 83 is cut away in this illustration, and a large area of ​​the actuating assembly 85 is also not visible in this illustration. The cranks 7 are mounted laterally on both sides onto a toothing of the bottom bracket spindle 18. Behind the toothing, on both sides of the bottom bracket spindle 18, are retaining rings 33 and a spacer sleeve 28, which form a stop for the cranks and simultaneously axially fix the inner ring of the left ball bearing 32. Shaft sealing rings 31 on both sides of the bottom bracket spindle ensure that the oil filling 72 cannot escape from the right and left housings 34, 35.In the center of the bottom bracket spindle is a spline 73 onto which an axially movable freewheel body 46 is mounted in a rotationally fixed manner. On its left side, it has a sawtooth-shaped face toothing which is pressed by a spring 50 against a complementary toothing on a fixed freewheel body 46 and engages positively. The axially fixed freewheel body 47 is part of a hollow input shaft 60 which is rotatably mounted coaxially on the bottom bracket spindle 18 by means of plain bearings 48. The hollow input shaft 60 cannot move axially because it is secured in place by two retaining rings 33. A sensor 59 is arranged on the outer surface of the hollow input shaft 60. The cyclist's torque is thus transmitted from the pedals via the cranks 7 on both sides into the bottom bracket spindle 18 and then further into the hollow input shaft 60.There, a signal containing information about the torque can be generated via sensor 59, which rotates together with the input hollow shaft 60 during operation. Together with the sensor 59, which in an advantageous embodiment is designed as a strain gauge, not only the input hollow shaft 60 rotates, but also a rotating circuit board 44, which is capable of further processing the information about the torque. Parallel to and at a short distance from the rotating circuit board 44 is a stationary circuit board 45, which in this exemplary embodiment is fastened to the right-hand gearbox housing 34 via a screw connection 50. In an advantageous embodiment, the rotating circuit board 44 also contains sensors that are capable of determining the position, orientation, and speed of the input hollow shaft 60 in relation to the gearbox housing, the stationary circuit board 45, and if applicable, to the earth's magnetic field or gravity.According to the prior art, signal transmission between the rotating and stationary circuit boards 44, 45 can, for example, be wireless via radio. Likewise, the energy required on the rotating circuit board 44 can be transmitted inductively from the circuit board 45 fixed to the housing. Other types of transmission are also possible. In an advantageous embodiment, the rotating circuit board 44 and the circuit board 45 fixed to the housing are located centrally near the bottom bracket shaft 18, exactly between the first gear stage 74, which is located on the left in the direction of travel, and the second gear stage, which is located on the right in the direction of travel. The novel bottom bracket gear system 10, as shown in Figure 4, has three drive gears 41, 42, and 43, which are coaxially and firmly connected to the hollow input shaft 60. In the embodiment shown, the drive gear 41 has twenty teeth, the drive gear 42 has thirty-two teeth, and the drive gear 43 has 53 teeth.In an advantageous, space- and weight-saving design, these gears are made from a single piece and are connected to the input hollow shaft 60 in a rotationally fixed manner via a spline 73. Axial locking is achieved, for example, by a shaft nut 29, which presses the drive gears axially against a shoulder of the input hollow shaft 60. The strength of the drive gear 41 with 20 teeth can be greatly increased if the lateral flanks of this spur gear are materially connected to the lateral flat surface 76 of the drive gear 42. In this embodiment, the teeth are connected to one another laterally via a web. In addition, a very narrow design is achieved if the rotating plate 49 is attached directly to one of the drive gears 41, 42, 43.If the largest drive gear 43 is located far out in relation to the hollow input shaft 60, there is sufficient space even for large electronic components 77, which are located on the circuit board 45 fixed to the housing. The teeth of the three drive gears 41, 42, 43 roll with the teeth of the idler gears 51, 52, 53 during operation. The idler gears are arranged coaxially to the selector shaft 67. The rotation axis X2 of the selector shaft 67 is located at a distance parallel to the rotation axis X1 of the bottom bracket shaft 18. The drive gear 41 with 20 teeth is connected to an idler gear 53, which also has 20 teeth. The drive gear 42 with 32 teeth is connected to an idler gear 52, which also has 17 teeth. The drive gear 43 with 53 teeth is connected to an idler gear 51 with 15 teeth. The selector shaft 67 is mounted in the left housing 35 via a ball bearing 28.The axial securing of the ball bearing 28 is achieved via retaining rings 33 and a spacer sleeve 28. To ensure assembly and tightness, a left protective cap 24 is located on the outside of the left gear housing 35 in this embodiment. In an advantageous embodiment, the idler gear with the smallest number of teeth is located at the outer end of the selector shaft 67 near the side wall of the left gear housing 35 and is connected to the largest drive gear. In this way, the shape of the selector shaft 67 can be selected such that the deflection of the selector shaft 67 due to the radial gearing forces is minimized. This idler gear with the smallest number of teeth has further properties: An optional needle bearing 27 is located between the idler gear 51 and the selector shaft 67. In addition, this idler gear with the smallest number of teeth has an internal toothing 57 that is axially spaced laterally from the running toothing.This design is advantageous for the service life of the running gearing, since here, too, the teeth are laterally connected to one another via a ring 78. In this advantageous embodiment, this integrally connected ring 78 carries an internal toothing 57. A clutch body 58 can positively engage this internal toothing 57 and enable the idler gear 51 to transmit torque to the selector shaft 67. The idler gears 52 and 53 also have internal toothings 57 into which clutch bodies 58, which are movably embedded in the outer surface of the selector shaft 67, can positively engage. The clutch bodies 58 are part of the clutch means K1 to K6. As already described above, the clutch bodies 58 are part of the clutch means. If the clutch means K1, K2 or K3 are in an activated state, the idler gears 51, 52, 53 can only transmit torques in one direction to the selector shaft 67.To ensure this function, the clutch means are constructed in such a way that torque can only be transmitted in one direction due to the shape of the internal toothing 57 and with the aid of springs (not shown). In the opposite direction, the clutch body 58 slides on the internal toothing 57 and no torque can be transmitted. Likewise, the clutch means K1, K2 or K3 can assume an inactive state. In this state, the clutch bodies 58 are brought into a position with the aid of pivotable supports 61, 62 or 62 and with the aid of springs (not shown) such that the clutch bodies 58 are no longer connected to the internal toothing 57 of the idler gears. In this inactive state, the respective idler gears can slide quietly on the selector shaft. The following table shows the three possible gear ratios of the first gear stage 74 depending on the state of the clutch means K1, K2 and K3.

[0066] Table 1

[0067] The table shows that the selector shaft 67 always rotates at least at the same speed as the bottom bracket shaft. This design is advantageous in that higher torques never arise on the selector shaft 67 than on the bottom bracket shaft. The torques on the selector shaft 67 are even much lower when the clutch means K3 or K2 are activated. The innovative selector shaft 67 shown has several non-coaxial bores in which several pivotable supports 61-66 are located. The supports are cylindrical components that can pivot about their own axes and extend out of the selector shaft 67 at one axial end. In the design shown, these pivotable supports 61-66 extend out to the right and each have a pinion 79 at their right end, which in turn is connected to the respective internal toothing 71 of two components of a stepping gear 70.In this embodiment, the rotational axes of the pivotable supports 61-66 are located in the sectional plane of the illustration in Figure 4. The pivotable supports can also be located at any other position within the selector shaft 67. The selector shaft is firmly connected to a reference gear 69 on the right-hand side. This reference gear is designed such that it also acts as an axial stop for the inner ring of the ball bearing 32'. Directly to the side next to the reference gear 69 is the actuating gear 68. Both gears have external teeth. The actuating gear 68 is mounted on the reference gear 69 via a plain bearing 48 and is secured axially outwardly directly on the right-hand side cover 81. The actuating gear 68, the reference gear 69, the stepping gear 70 with the two associated internal gears 71 and the six pivotable supports 61, 62, 63, 64, 65, 66 form part of the actuating means.By changing the rotational position of the actuating gear 68 in relation to the reference gear 69, all six supports 61, 62, 63, 64, 65, 66 are pivoted, thus actuating the clutch means K1, K2, K3, K4, K5, and K6. Within the second gear stage 75, the idler gear 54, which has 20 teeth, is coupled to the selector shaft 67 via the activated clutch means K4. Likewise, within the second gear stage 75, the idler gear 55, which has 21 teeth, is coupled to the selector shaft via the activated clutch means K5. The clutch means K6 couples the idler gear 56, which also has 21 teeth, to the selector shaft 67 in the same way. The internal gears 57 are geometrically identical in the first and second gear stages 74, 75, but are arranged in a mirror image, since in the second gear stage 75 the torques must be transmitted from the selector shaft 67 to the idler gears 54, 55 or 56.In the first gear stage 74, the torques from the idler gears 51, 52, and 53 are transmitted to the selector shaft 67. The hollow output shaft 36 is arranged coaxially to the bottom bracket shaft 18 and, in an advantageous embodiment, is integrally connected to three output gears. The output gear 37 has 20 teeth, is located centrally in the gear box, and meshes with the idler gear 54, which also has 20 teeth. The output gear 38 has 32 teeth and meshes with the idler gear 55, which has 21 teeth. The output gear 39 has 26 teeth and is located on the far right of the housing wall of the right-hand gear housing 34. It meshes with the idler gear 56, which has 21 teeth.In general terms, the structure can be summarized as follows: It is a bottom bracket gear 10 with an actuating device, in particular for a muscle-powered vehicle, with a first partial gear 74 and a second partial gear 75 which are connected in series for power transmission, wherein the first partial gear 74 and the second partial gear 75 have a selector shaft 67 on which a plurality of loose wheels 51-56 are mounted, which form wheel pairs of the respective partial gear with a corresponding plurality of gear wheels 37, 38, 39, 41, 42, 43, wherein the loose wheels can be connected to the selector shaft 67 by means of pivotable coupling bodies 61-66.It is clear from the illustration that the novelty is characterized in that the selector shaft 67 has a plurality of axial bores, and the plurality of axial bores of the selector shaft 67 are not coaxial with the selector shaft 67, and a pivotable support 61-66 is located within each of the axial bores, and each pivotable support 61-66 is connected directly or indirectly to exactly one clutch body exclusively via its cylindrical outer surface. The following table shows the three possible ratios of the second gear stage 75 depending on the state of the clutch means K4, K5, and K6:.

[0068] Table 2

[0069] Here, too, it is noticeable that the speed either remains constant or is reduced from the selector shaft to the hollow output shaft in the second gear stage 75. This innovative design ensures good strength in the running gears, because many gears have a small number of teeth and a large module. The output gears 37, 38, and 39 are connected by webs on the side surfaces of the teeth and are formed in such a way that excessive tooth root stresses can be prevented. Since the hollow output shaft 36 rotates at different speeds than the bottom bracket shaft 18, a double needle bearing 27 is provided. The bearing spacing is specified by a spacer sleeve 26. In order to guide the torque out of the bottom bracket gear 10, an output drive 30 is attached to the hollow output shaft 36 by means of a spline 73 and is axially secured by means of a shaft nut 29.This design also makes sense3,53, as it also secures the inner ring of the ball bearing 32". To prevent oil from escaping from the bottom bracket gear 10, a shaft seal 31 is arranged between the bottom bracket shaft 18 and the hollow output shaft 36. In addition, the shaft seal 3T ensures a seal between the output drive 30 and the right-hand gear housing 34. The output drive 30 transmits the torque to the front pulley 8. Both components are screwed together. This preferred, novel design of a bottom bracket gearshift provides nine gears through the combination of gear stages 74, 75. The following table shows the nine possible gear stages of the bottom bracket gear 10 depending on the condition of all clutch means K1 to K6:.

[0070] Table 3

[0071] The entire assembly of the six coupling means K1 to K6 is shown in dashed lines in Figure 4 and marked with the reference symbol K.

[0072] It can be seen that the exemplary design of the new device provides nine gears with even increments, all between 23.1 and 23.8%. This gear increment and the entire range of gear ratios of 538% is a very advantageous design, especially for bicycles with electric assistance. The new device can be used in all e-bike categories, as the driving speed, which also depends on the diameter of the vehicle's driven wheel, can be adjusted using the so-called secondary gear ratio. The secondary gear ratio is the ratio of the number of teeth on the front pulley 10 and the rear pulley, which is usually mounted on the rear wheel 13. However, the new device can be used not only on bicycles with electric assistance; this innovative bottom bracket gear system can also be used on vehicles without auxiliary drive.The 538% gear range even allows for use on a mountain bike. By omitting individual gear pairs, the new system can be manufactured more cost-effectively, allowing it to be used in categories that require fewer gears and a narrower gear range.

[0073] Figure 5 shows a cross-section through plane AB from Figure 4. The bottom bracket spindle 18 rotates about the rotation axis X1. Visible in this section is the shaft sealing ring 31, which prevents oil from escaping from the left gear housing 35. Also visible is the largest drive gear 43, which has 53 teeth. As already explained, this gear is used exclusively for the three fastest or longest gear ratios in gears seven, eight, and ninth. According to the advantageous embodiment of the innovation, the mechanical power of the auxiliary drive is also fed via this gear 43 in order to save weight and installation space. Generally speaking, at least one gear, which is arranged coaxially to the bottom bracket spindle 18, is constantly connected to two other gears, one of the two gears being a stepped gear 98.A stepped gear 98 consists of two gears that have a different number of teeth, are aligned coaxially with each other, and are firmly connected to each other. In a preferred embodiment, a stepped gear 98 is manufactured from a single piece. In the illustrated embodiment, gear 87, which has 15 teeth, and gear 88, which has 30 teeth, are designed as a single-piece stepped gear 98 and rotate about rotation axis X7. X7 is thus a rotation axis of the reduction gear. This stepped gear 98 is mounted on a housing-fixed axle 99 by means of a 32'" ball bearing. In order to make the electric motor used small and lightweight, it is designed for a high speed, and this high speed is then reduced with the help of a multi-stage reduction gear to the natural pedaling frequency of the person, which drives the bottom bracket spindle 18 at approximately 50-90 revolutions per minute.At least one of the new gears, located coaxially with the bottom bracket, is used both as a component of the reduction gear and as a component of the manual transmission. In the illustration, this is gear 43. To illustrate the entire reduction gear in Fig. 5, an additional cutout 95 is provided, showing the first reduction stage. The shaft 100 of the electric motor rotates about the rotational axis X3 and carries the gear 91 with 12 teeth. The gear runs in the same oil bath as all the other gears. Behind the gear 91 is a shaft seal 31". This ensures that the rotor and stator, with all magnets, windings, and also the power electronics circuit board with the connection of the individual motor phases 93, are located in a dry chamber 94, protected from oil. The circuit board with the motor controller is not shown in detail.Visible, however, are the plug contacts 96, which are also located in the dry area and are connected to the circuit board. The bottom bracket gear, which is often referred to as the drive system when combined with an electric auxiliary drive, is connected to the control element on the handlebars via the plug contacts. The battery, sensors, and display elements are also connected to the drive system via these plug connections. The gear 91 with 12 teeth is connected to the gear 92 with 55 teeth. The gear 92 is connected via a freewheel to the gear 90, which has 14 teeth and is designed as a single-piece shaft. This freewheel 97 rotates about the rotation axis X5 and ensures that the cyclist does not have to drag the electric motor empty or even operate it as a generator when the auxiliary drive is switched off.Gear 89 has 21 teeth, rotates around the rotation axis X6, and establishes a connection between gear 90 and gear 88. The following table shows the ratios of the individual reduction stages and their rotation axes:.

[0074] Table 4

[0075] The entire reduction gear is advantageously designed so that the motor speed at shaft 100 is reduced by a factor of 34.7 up to the bottom bracket shaft 18. The size of gear 89 has no influence on this overall gear ratio. However, this gear 89 bridges the gap to the adjacent gear stage within the new design.

[0076] Figure 6 shows a perspective view of the bottom bracket shifting system 10 from Figure 2. It shows the structure of the innovative bottom bracket shifting system 10 with an electric auxiliary drive in an advantageous embodiment. The electric actuation is not visible in this view. The left and right housings, the side covers, all screws, the pedal cranks 7, the front pulley 8, the plug contacts, and the circuit board with the power electronics are not shown.This is an exemplary representation of the bottom bracket transmission, in particular for a muscle-powered vehicle with an additional electric drive, with a first partial transmission 74 and a second partial transmission 75, which are connected in series for power transmission, wherein the first partial transmission 74 and the second partial transmission 75 have a selector shaft 67 on which a plurality of loose wheels 51, 52, 53, 54, 55, 56 are mounted, which form wheel pairs of the respective partial transmission with a corresponding plurality of gear wheels 43, 42, 41, 37, 38, 39, wherein the loose wheels can be connected to the selector shaft 67 by means of coupling bodies.Additionally, the advantageous embodiment is characterized in that the smallest idler gear 51 forms a gear pair with the largest drive gear 43 and is arranged laterally to the left in the direction of travel, and that the largest drive gear 43 is also in a power-transmitting connection with a further gear 87, wherein this further gear 87 is in indirect or direct connection to the shaft 100 of the additional electric drive 102. In an advantageous embodiment, this further gear 87 is located near or directly below the smallest idler gear 51. If one considers the cylindrical volume that encloses the largest drive gear 43, the left ball bearing of the bottom bracket shaft is also located in this volume. In this advantageous construction shown, the largest drive gear 43 has a bell-like shape and is integrally connected to two further drive gears 41 and 42.In addition, the three output gears 37, 38, and 39 are also integrally connected to one another. Since this design is very space-saving, in this advantageous embodiment, two circuit boards 44, 45 with electronic components can be placed coaxially and centrally to the bottom bracket shaft 18 between the first and second partial transmissions 74, 75 within the sensor arrangement. One circuit board 44 rotates at the same speed as the bottom bracket shaft 18, and the second circuit board 45 cannot move relative to the housing. Both circuit boards are arranged directly next to one another, exchange electrical signals with one another, and at least one signal representative of the cyclist's torque is generated on one of the two circuit boards.Additionally, it is advantageous if the plate, which is stationary relative to the housing, has attachment points 103 that are connected to the housing, and the plate, which rotates at the same speed as the bottom bracket spindle, has attachment points that are connected to one of the three drive gears 41, 42, 43. In a further advantageous embodiment, the auxiliary electric drive 102 with the rotor and stator is preferably located in front of the second partial transmission 75 in the direction of travel, so that the space on the left-hand side in the direction of travel can be used for the necessary gear stages 91, 92, 90, 89, 87, which reduce the speed of the electric motor 102. The gear pairs that reduce the speed of the electric drive motor 102 are located, in an advantageous embodiment, in the direction of travel in front of and below the first partial transmission.More generally, the rotational axes X5, X6, X7 of the reduction gear stages and the rotational axis of the electric motor X3 are located below a plane spanned by the rotational axis X1 of the bottom bracket shaft 18 and the rotational axis X2 of the selector shaft 67. In an advantageous embodiment, the circuit board 104, which electronically determines the position or orientation of the rotor of the electric motor 102, is located to the right of the electric motor 102 in the direction of travel. In this way, this circuit board 104 can be housed in a dry installation space, and the gear 91, which is located on the motor shaft 100, can run in an oil bath. The reaction forces of the gear 91 can be effectively absorbed by a needle bearing 27, and the electric motor 102 can be effectively sealed against the oil bath with a shaft seal 31.It can also be seen in Figure 6 that the idler gears have running teeth on their outer surface, wherein the side surfaces of the teeth of at least one idler gear 51 are connected to one another on one side via a web 101. This design is very advantageous for the durability of the teeth. In other words, the innovation is characterized by the fact that a cylindrical disc or ring 78 is located axially next to the idler gear 51, which is integrally connected to the gear and has at least a diameter that is larger than the root circle of the idler gear 51. Axially laterally next to the cylindrical disc, also integrally connected, is the clutch teeth, which are designed as internal teeth and can be connected to the clutch body. The idler gear 51, the cylindrical disc and the clutch teeth are designed as a single piece or are joined integrally.

[0077] Figure 7 shows a perspective view of the selector shaft 67 assembly. The components arranged on the selector shaft 67 are shown in section. In this advantageous exemplary embodiment, the selector shaft has a smaller diameter on the left side than in the middle of the shaft. On the left side, the selector shaft 67 is mounted in a housing (not shown) via a ball bearing 32. The ball bearing 32 is axially fastened to the shaft collar 105 via a spring ring 33 and a spacer sleeve 28. The selector shaft also has a smaller diameter on the left side compared to the middle of the shaft because the idler gear 51 only has 15 teeth, resulting in a smaller diameter. The illustration shows that the idler gears 51, 52, 53, 54, 55, 56 can be connected to the selector shaft 62 by means of coupling bodies 58.This preferred embodiment is characterized in that these six clutch bodies 58 can form a positive connection with the matching internal toothing. In Figure 7, only two clutch bodies 58 are visible. However, each of the idler gears 51, 52, 53, 54, 55, 56 has an internal toothing 57. The novelty in this advantageous embodiment is characterized in that on at least one idler gear 51, the internal toothing 57 is laterally spaced from the external toothing. This embodiment also shows that each clutch body 58 is connected to a worm spring 106. Each worm spring 106 is located in a groove 107 on the outer surface of the selector shaft 67. In the illustration, there are six worm springs 107, which ensure the correct function of the clutch bodies 58.Since the idler gears 51, 52, 53, 54, 55, 56 run in an oil bath and are therefore well supported axially relative to one another and radially relative to the selector shaft 67, they can assume different speeds relative to one another without significant frictional losses. The axial bearing play can be adjusted by correctly selecting the thickness of a sliding washer 108. On the right-hand side, the selector shaft 67 is also mounted in the right-hand gear housing 34 via a ball bearing 32'. Axially, the ball bearing 32' is supported on another collar 105' and on the reference gear 69 of the selector shaft. The reference gear 69 is attached to the selector shaft 67 and rotates at the same speed during operation. Next to the reference gear 69 is the actuating gear 68 of the selector shaft 67. The switching process is carried out by rotating this actuating gear 68 in relation to the reference gear 69.By rotating this actuating gear 68, which also has an internal toothing 71, three of the six pivotable supports 61, 62, 63, 64, 65, 66 shown are directly rotated within the bores located on the right-hand flat side of the selector shaft 67. Of these pivotable supports 61, 62, 63, 64, 65, 66, only the toothings at the ends are visible in Figure 7 and, for better visibility, are not labeled with reference numerals. In different rotationally adjustable positions of the pivotable supports 61, 62, 63, 64, 65, 66, the coupling bodies 58, which are located within a recess 107 on the outer surface of the selector shaft, can assume different states. The remaining three of the six pivotable supports 61, 62, 63, 64, 65, 66 shown are rotated only at specific times within the bores of the switching shaft 67, since they are connected to the actuating gear 68 via a stepping gear 70.This design has the advantage that a rotation of, for example, 40 degrees on the actuating gear 68 causes a rotation of, for example, 120 degrees on the respective pivotable supports 61, 62, 63, 64, 65, 66. The nine gear steps shown above are thus shifted through with the help of a rotational movement of 8 times 40 degrees on the actuating gear 68. This corresponds to a rotation of 320 degrees. The useful new gear ratios mentioned above can be easily implemented within the scope of the illustrated embodiment if the gear unit is characterized in that the root circle diameter of the external toothing of the idler gear 51, which has internal toothing 57 that is laterally spaced apart, is characterized in that the root circle diameter is smaller than or equal to the maximum diameter of the internal toothing.This design can be improved even further in terms of strength if the novelty is characterized in that at least this one loose wheel 51, which has an internal toothing that is laterally spaced, is distinguished in that the teeth of the external toothing, which represents the running toothing, are laterally materially connected to one another. In parallel with this, a further reinforcement is also obtained if at least the loose wheel 51, which has an internal toothing 57 that is laterally spaced, is distinguished in that the teeth of the internal toothing 57 are laterally materially connected to one another. It is clear from the illustration that the selector shaft 67, in the region in which it is connected to the loose wheel 51, which has an internal toothing 57 that is laterally spaced, is distinguished in that the selector shaft 67 has two different outer diameters in this region.Here, the larger outer diameter is preferably located within the clutch toothing 57. Preferably, the idler gear 51, which has an internal toothing 57 spaced laterally apart, meshes with the largest gear or drive gear 43, which is located coaxially with the bottom bracket shaft 18. The plane E1 is perpendicular to the rotational axis of the selector shaft 67 and is located centrally in the idler gear 56.

[0078] Figures 8a, 8b, and 8c each show a section through the plane E1 of the idler gear 56 of the bottom bracket shift, viewed from the left. The gear housing on the right is not shown in any of the figures. Also visible in all figures is the clutch means K6, consisting of the internal toothing 57, the clutch body 58, the worm spring 106, and the pivotable supports 61, 62, 63, 64, 65, 66. It is clear from the illustration that only one pivotable support 66 is responsible for one clutch body 58. Preferably, none of the bores in which the pivotable supports 61, 62, 63, 64, 65, 66 are arranged are concentric with the selector shaft 67.In a preferred embodiment, the novel bottom bracket gearshift is designed such that the bores in which the pivotable supports 61, 62, 63, 64, 65, 66 are arranged are at the same distance from the outer surface of the selector shaft 67, with each bore also having the same distance from the two adjacent bores. In a preferred embodiment, the clutch body 58 is provided with a slot so that the worm spring 106 can exert a defined force on the clutch body 58. Worm springs are subjected to tensile stress and can be connected at the ends to form a ring shape. Due to the subsequent assembly, the worm spring is often used inside shaft seals and is therefore an industrially produced and cost-effective machine element. Figure 8a shows the clutch body 58 completely submerged within the pocket, which is milled as a recess on the outer surface of the selector shaft 67.The clutch body 58 is not connected to the internal toothing 57 of the idler gear 56. The idler gear 56 can rotate freely in both directions of rotation. The clutch means is deactivated in both directions of rotation. The pivoting support 66 is not in direct contact with the clutch body. Figure 8b shows the clutch body 58 fully coupled into the internal toothing 57 of the ring gear. The clutch means is activated. The cylindrical outer surface of the pivoting support 66 is in force-transmitting connection with the clutch body 58. In this state, the selector shaft can transmit a torque in a clockwise direction to the idler gear 56. Figure 8c shows the state when the idler gear 56 rotates clockwise faster than the selector shaft 67 when the clutch means is activated. In this state, the back of the clutch body 58 slides over the internal toothing 57. This state can occur briefly during the switching process.

[0079] Figures 9a, 9b, and 9c show section A1 from the sectional view of Figure 8 in a schematic representation, quite generally, for such a coupling means K according to the novelty. The selector shaft 67 rotates about the rotational axis X2. In this exemplary representation, the idler gear 109 rotates counterclockwise and drives the selector shaft 67. The internal toothing 57 is located concentrically in the idler gear 109. It has bearing surfaces 112, pressure surfaces 110, and sliding surfaces 111. Preferably, the selector shaft 67 has three or more than three axial bores 113, which are arranged parallel or almost parallel to the axis X2 of the selector shaft 67. Figures 9a, 9b, and 9c representatively and schematically show only one of these axial bores 113. The pivotable support 114 is located in the bore 113.The pivotable support 114 can, as shown in Figures 9a and 9b, assume a first state in which the pivotable support is directly connected to exactly one clutch body 58. In this first state, the clutch means is activated, and it can also be seen that the clutch body 58 can be brought into force-transmitting connection with the idler gear 109. The force-transmitting connection to the idler gear 109 is achieved when the idler gear 109 rotates counterclockwise, as shown in Figure 9a, and drives the selector shaft 67. The force-transmitting connection to the idler gear 109 is not achieved when the idler gear 109 rotates clockwise, as shown in Figure 9b, and cannot drive the selector shaft 67, since the clutch body 58 cannot form a positive connection with the pressure surface of the internal toothing 110.When the idler gear 109 rotates clockwise, as shown in Figure 9b, the clutch body 58 slides, among other things, against the sliding surfaces of the internal gearing 111, and no torque can be transmitted from the idler gear 109 to the shaft 67. Within this preferred exemplary embodiment, the clutch body 58 has a spring mounting surface 117 that is constantly in contact with a spring 118, for example, a worm spring 106, and ensures that the clutch body 58 can assume different states and cannot become incorrectly jammed between the internal gearing 57 and the selector shaft 67.To prevent the worm spring 106 from becoming jammed during operation between the selector shaft 67, the clutch body 58, and the internal toothing 57 of the idler gear 108, the selector shaft preferably has several grooves on its cylindrical outer surface in which the almost annular spiral springs, also called worm springs 106, are inserted. For the same reason, the clutch body 58 also has a groove in which the almost annular spiral springs, also called worm springs 106, are inserted. The aforementioned spring mounting surface 117 is located within this groove.

[0080] Looking at Figure 9c, it can be seen that the pivotable support 114 can assume a second state in which the pivotable support 114 is not connected to the clutch body 114. In this second state, this clutch body 114 cannot be brought into force-transmitting connection with the idler gear 109 and, regardless of the direction of rotation of the idler gear 109, no surface of the internal toothing 57 can come into contact with the clutch body 58. The idler gear 109 can slide silently on the selector shaft 67. The clutch means is shown deactivated in Figure 9c. It is also clear from Figure 9 that the recess 107, in which a clutch body 58 is located, is connected via an opening 119 to the bore 113, in each of which a pivotable support 114 is located.

[0081] Figure 10a shows the clutch means according to the novelty in a schematic representation of a section of Figure 9a. The idler gear 109 and the selector shaft 67 are only shown in a section and are capable of rotating about the rotation axis X2. The idler gear 109 has an internal toothing 57 that is arranged symmetrically and concentrically within the idler gear 109. The internal toothing 57 has pressure surfaces 110 that transfer the forces from the idler gear 109 to the pressure surfaces 116 of the clutch body 58. In a preferred embodiment, the pressure surfaces 116 and the pressure surfaces 110 are both slightly curved in the same direction. The force arrow FK 124 represents these forces in the illustration. This type of arrangement is of course also capable of transferring the forces in reverse from the clutch body to the idler gear 109.To describe the preferred principle, however, the following description will assume that the forces are transmitted from the idler gear 109 to the clutch body 58. The clutch body 58 is located on the selector shaft 67 within a pocket 107, which can also be described as a depression within the outer surface of the selector shaft 67. The clutch body 58 is mounted on surface 137 on the selector shaft 67 and can therefore rotate about the rotational axis X8. The force F. K 124, which is applied by the idler gear 109 to the coupling body 58, is derived from the support force F a 140 into the selector shaft 67. However, since the force FK 124, which is introduced into the clutch body 58 by the idler gear 109, has a lever arm l with respect to the rotational axis X8 K, a torque is also generated, and the clutch body 58 attempts to rotate clockwise around the axis X8. However, this rotational movement is prevented by a torque MA because the pivoting support 114, which is arranged within an axial bore 113 in the selector shaft 67, supports the clutch body 58 with the force FB 125. This results in an equilibrium of the torques around the axis X8:

[0082] FK* IK = F B * IB = MA

[0083] The lever arm l Kis preferably short and the lever arm IB somewhat longer, as this allows the support force FB on the pivoting support 114 to be minimized. Thus, within the scope of the innovation, this is a self-disengaging clutch body 58. The shape of the clutch body 58 and the internal toothing 57 are selected such that, when the support 114 is pivoted out, the torque Ma overcomes the static friction between the pressure surface 116 of the clutch body 58 and the pressure surface 110 of the internal toothing 57 and deactivates the clutch means. The mechanical work required to overcome the static friction is thus applied by the cyclist themselves. The actuating means only has to apply the mechanical work to move the pivoting support. The friction on the pivoting support is determined exclusively by the force FB, which has been minimized within the scope of the advantageous design of the clutch body.The torque MB 126 can be easily applied to the pivoting support 114 by an actuating means, since the pivoting support 114 rotates about its own axis X9. In an advantageous embodiment, the pivoting supports 114 have a cylindrical shape, wherein the diameter of the cylinder is at least three times smaller than the diameter of the selector shaft. A cylinder that is to be pivoted through a certain angle within a bore under radial load can be pivoted more easily the smaller its diameter. In an advantageous embodiment, the bearing surface 139 of the pivoting support 114 on the selector shaft 67 and the surface within the axial bore 113 of the selector shaft 67 are made of steel and hardened.If the axial bore 113 is connected to the recess 107 in the outer surface of the selector shaft 67 only via a single opening 119, the strength of the selector shaft 67 is maintained, since the selector shaft 67 is not weakened by a large concentric bore, as is usually the case in prior art designs.

[0084] In comparison to Figure 10a described above, Figure 10b shows the clutch means according to the prior art in a comparable schematic representation. The force Fk 124, which is transmitted from the idler gear 109 via the pressure surface 110 of the internal toothing 57 to the clutch body 58, ensures a counterclockwise torque Mp about the rotational axis X8. In this embodiment according to the prior art, this torque Mp leads to self-locking. The clutch body 58 transmits the forces completely and exclusively via the bearing surface 137 of the clutch body on the selector shaft 67. The torque Mp ensures that the clutch body is supported on the internal toothing 57 with the force Fr. In order to initiate a switching operation according to this prior art, the frictional force resulting from the surface pressure on the pressure surface 116 of the clutch body must be completely compensated by the applied force F ar136 of the camshaft 138. Due to the relatively long lever arm L n 134 on the camshaft 138, which according to the state of the art is usually mounted coaxially to the selector shaft 67, the torques M introduced by the actuating means must n be very high in order to release the coupling body 58 from the internal toothing 57. With the same force FK, the actuating torque MB in the novel design according to Figure 10a is significantly lower than the actuating torque M n in prior art configurations according to Figure 10b. This demonstrates that the novel design of the shifting device within the bottom bracket shifting system can perform a shifting operation even under load.

[0085] Looking at Figure 10a, it can be summarized that an exemplary preferred bottom bracket transmission with a switching device is characterized in that loose wheels have concentric bores and wherein the bores are designed with internal toothings 57 and wherein the switching shaft 67 and the clutch body 58 and at least some of the pivotable supports 114 are located within the bores and wherein the internal toothings 57 have pressure surfaces 110 which transmit the forces from the loose wheel 109 to the pressure surfaces 116 of the clutch body 58 and wherein the pressure surfaces 116 of the clutch body 58 and the pressure surfaces 110 of the internal toothing 57 are both slightly curved in the same direction.In addition, this exemplary embodiment is characterized in that the clutch body can assume a state in which the force transmitted from a loose wheel to this clutch body can be simultaneously guided from the clutch body into the selector shaft and into a support, and wherein the support can be changed in terms of its position and orientation relative to the selector shaft via an actuating means.

[0086] Figure 11a shows the selector shaft 67 from Figure 7 in perspective, without the idler gears 51 to 56. The right housing 34 and the left housing 35 are also not shown. This illustration is exemplary. On the left side is the ball bearing 32, which is axially secured by a retaining ring 33. To the right of the ball bearing 32 is a spacer sleeve 28. The idler gears are supported axially to the left against this spacer sleeve 28 and to the right against the shaft collar 120". The selector shaft 67 has several grooves 142 on its cylindrical outer surface into which almost annular spiral springs 106 can be inserted. The annular spiral springs 106 are not shown in Figure 11a. In this embodiment, the selector shaft 67 has six chambers 143 inside it, which are arranged parallel or almost parallel to the axis of the selector shaft. These chambers are not coaxial with the rotational axis X2 of the selector shaft 67.Within each of the six chambers, there is a pivotable support 61-66. Each pivotable support 61-66 can assume a first state in which the pivotable support 61-66 is directly or indirectly connected to exactly one clutch body 144-149. It can be seen that the clutch body 149 is folded up and thus, in this first state, this clutch body 149 is in force-transmitting connection to the idler gear 56 (not shown). It can also be seen in the illustration that the outer surface of the selector shaft 67 has recesses 107 in which the clutch bodies 144-149 are located. Only three clutch bodies 142, 146, and 149 are visible in Figure 11a. The plurality of recesses 107 are preferably evenly distributed over the circumference of the outer surface.To enable the clutch bodies to be controlled, the six recesses 107 are each connected via an opening 119 to the six chambers in which the pivoting supports 61-66 are located. The ball bearing 32' is located on the right side. The ball bearing 32' is axially fixed by the reference gear 69. The actuating gear 68 is located on the far right of the selector shaft 67 and is capable of actuating the six pivoting supports 61-66.

[0087] Figure 11b shows the assembly from Figure 11a in the same perspective view without the selector shaft 67, without the ball bearings 32, 32' and without the spacer sleeve 28. It can be clearly seen in the illustration that two of the six pivoting supports have assumed a first state in which the two supports 61 and 66 are directly connected to exactly one coupling body 144 and 149. In this state, the coupling bodies are folded up and can transmit forces. The coupling means K1 and K6 are activated. This first state corresponds to the principle described in the illustration in Figure 9a. The four pivoting supports 62, 63, 64, 65 are in a second state in which each of the four pivoting supports 62, 63, 64, 65 is not connected to one of the respective coupling bodies 142, 143, 144, 145.This decoupling is possible because the pivotable supports 61, 62, 63, 64, 65, 66 have a cylindrical shape and have recesses 150 on the cylindrical outer surface 151, and the recesses 150 are located near the coupling bodies 141-146. In this second state, the coupling bodies are folded down and cannot transmit any forces. The coupling means K2, K3, K4 and K5 are deactivated. This second state corresponds to the principle described in the illustration in Figure 9c. In this second state, these coupling bodies cannot be brought into a force-transmitting connection with an idler gear. The pivotable supports 61-66 have different lengths and are located within the selector shaft 67 in a chamber with a cylindrical shape. This shape can preferably be implemented in production by means of axial bores with different depths.

[0088] This illustration of the selector shaft of the innovative bottom bracket transmission also clearly shows that a first sub-transmission and a second sub-transmission are connected in series for power transmission: Within the first sub-transmission, the clutch bodies 144, 145, and 146 transmit torque from the idler gears 51, 52, and 53 to the selector shaft 67. The clutch bodies 147, 148, and 149 are arranged within the selector shaft 67, rotated by 180 degrees, and are part of the second sub-transmission. In order to transmit torque across both sub-transmissions, one of the three clutch bodies 144, 145, and 146 and one of the three clutch bodies 147, 148, and 149 must be folded up. Each sub-transmission has three gears. The series connection of the sub-transmissions results in nine gears. To change gears from one gear to the next, the three pivoting supports 61-63 or 64-66 in the partial transmission rotate simultaneously by 120 degrees around their own axis of their cylindrical shape.The recesses 150 on the cylindrical outer surfaces of the pivotable supports must therefore extend over a range of 240 degrees in this exemplary embodiment, since only a single gear in the partial transmission may be activated over a 360 degree pivoting movement.

[0089] Figure 11b also clearly shows that it is advantageous for the strength of the selector shaft 67 if the axial bores in which the pivotable supports 61-66 are arranged are at the same or a similar distance from the outer surface of the selector shaft 67. In this case, the shape of the coupling bodies 144-149 is also the same. If each bore is also at the same or a similar distance from the two adjacent bores, a good stress distribution can be achieved within the selector shaft. The coupling bodies 144-149 have a groove as a spring support surface 117, with the worm spring 106 within the groove ensuring that the functions of the coupling bodies 144-149 are achieved as described above.

[0090] The pivoting supports 61-66 extend laterally from the selector shaft 67 and are provided with gears 152, 153, 154, 155, 156, and 157 at their ends. Instead of gears, the pivoting supports 61-66 can also be provided with other gear elements for control. The exemplary design has six pivoting supports 61-66 with six actuating gears 152-157. The gears are not located in one plane. Three gears each, 152, 153, 154 and 155, 156, and 157, are located in one plane. Exactly those gears connected to the pivoting supports, those responsible for the first and second gear stages, must be located in one plane. In the advantageous embodiment, the actuating gears 152, 153, 154 for the first partial transmission are located in one plane, and the actuating gears 155, 156, 157 for the second partial transmission are located in a second plane. This is illustrated in Figure 11d.Figure 11d shows an enlargement of the right-hand section of Figure 11c. Each gear 152-157 has 13 teeth. The gears 152, 153, and 154, which are responsible for the coupling means K4, K5, and K6, are located on the outside. The gears 155, 156, and 157, which are responsible for the coupling bodies K1, K2, and K3, are offset slightly inward. The gears are preferably made in one piece with the pivotable supports 61-66. However, a design in which the gears 152-157 are attached and secured is also possible. To advantageously lock the angular position of the pivoting supports 61-66, the pivoting supports 61-66 have three recesses 158 on their outer surface at a distance of 120 degrees, into which a spring-loaded thrust piece 80 can engage. The spring-loaded thrust pieces 159 are screwed into the selector shaft 67 at the right end below the bearing seat of the ball bearing 32'.Each pivoting support 61-66 is assigned a resilient thrust piece 80. Each pivoting support 61-66 can lock into three positions after being actuated from the outside. The actuation should be designed such that, in this preferred embodiment, each pivoting support 61-66 is always rotated exactly 120 degrees for shifting from one gear to the next. Each individual pivoting support has two locking points at which the clutch means is deactivated. Each pivoting support has a further locking point at which the clutch means is activated. Considering Table 3 listed above in the text, it becomes clear that the pivoting supports of the clutch means K1, K2, and K3 only need to be moved between the third and fourth gears and between the sixth and seventh gears.In this preferred embodiment, the pivotable supports of the first partial transmission are moved simultaneously with the pivotable support of the second partial transmission only at two points in time so that the gears from one to nine can be shifted through.

[0091] Figure 12a shows a section of the right-hand side of the bottom bracket spindle, viewed from above. Only the bottom bracket spindle 67 with the right-hand gear housing 34, the idler gear 56, and the idler gear 55 are visible. Also visible are the actuating gear 68 and the reference gear 69. The novel bottom bracket gear is preferably characterized in that a reference gear 69 is laterally fixedly connected to the selector shaft 67, and an actuating gear 68 is in turn located laterally next to the reference gear. In a preferred embodiment, these two gears have external teeth of the same diameter, wherein the diameter is larger than the outer diameter of the selector shaft, and wherein the actuating gear 68 is connected to at least some of the pivotable supports via one or more gear elements, and wherein the actuating gear 68 is mounted on the reference gear 69.A shifting operation during the operation of the bottom bracket gearshift is carried out by rotating the actuating gear 68 relative to the reference gear 69 around the axis X2.

[0092] Figure 12b shows the section CD through the actuating gear 68 from Figure 12a. In this advantageous embodiment, the actuating gear 68 has, in addition to the external toothing, an internal toothing 71, wherein the internal toothing 71 is connected to three pinions 79, said pinions 79 being connected to the pivotable supports 64, 65 and 66. The actuating gear 68 is thus indirectly connected to the pivotable supports of the clutch means K4, K5 and K6, since these clutch means must be changed with each gear change according to Table 3 above. In this advantageous embodiment, the actuating gear 68 controls the gears 155, 156 and 157, since these are responsible for the clutch means K4, K5 and K6.It can also be seen in Figure 12b that the axial bores in which the pivotable supports 64, 65 and 66 with the gear wheels 155, 156 and 157 fastened thereon are arranged are evenly spaced on a pitch circle on the lateral axial plane surface of the selector shaft and wherein the pitch circle is arranged concentrically to the rotational axis X2 of the selector shaft 67.

[0093] Figure 13a shows a section of the right side of the bottom bracket spindle, viewed from above. The bottom bracket spindle 67 is concealed by the ball bearing 32' in this view. The gear housing 34, the idler gear 56, and the idler gear 55 from Figure 12a are not shown. Also visible is the reference gear 69, which has a short cylindrical ring 159 on its right-hand side, on which the actuating gear 68 is mounted.

[0094] Figure 13b shows the section EF through the reference gear 69 in Figure 13a at the level of the center of the short cylindrical ring 159. The section shows a stepping gear which allows the gears 152, 153, 154, which are responsible for actuating the clutch means K1, K2, K3, to be moved only during the periods when the actuating gear 58 is shifted from third to fourth and from sixth to seventh gear. The reference gear 69 is made in one piece together with a short cylindrical hollow shaft stub 159. The actuating gear 68 also has a short cylindrical ring 161, which is mounted in the ring 159. This ring 159 has a groove 162 in which a ball 165 is movably inserted. The actuating gear 68 with its ring 161 forms the input of the stepping gear 160.When the actuating gear 68 rotates, the ball 168 is radially displaced at specific angular transitions by a guide 166 on the inner surface of the ring 159 and can drive the internal ring gear 164, which is responsible for actuating the coupling means K1, K2, K3. In a preferred embodiment, the ring gears 164 and 71 have 39 teeth. The ring gear 164 forms the output of the indexing gear 160, since this ring gear 164 only moves in steps. A rotation of the ring gear 164 by 40 degrees causes the gears 152, 153, 154 to rotate by 120 degrees, since these gears preferably have 13 teeth. As already described above, it is thus possible to set the coupling means into two deactivated and one activated state within one rotation of the pivoting supports and to achieve the 9 gear steps according to Table 3. Figure 13b shows the innovation as an example in the first of 9 gears.The angular movement that must be performed on ring 161 to engage nine gear steps consists of eight individual movements of 40 degrees each, which are illustrated by arrows within Figure 13b. The nine gear steps are identified by Roman numerals. The illustration shows ball 165 in the first gear position, designated I. To engage second gear, ball 165 is rotated counterclockwise about axis X2 using ring 61 until the ball reaches position II. To engage third gear, ball 165 is rotated counterclockwise about axis X2 using ring 61 until the ball reaches position III. To shift from third gear to fourth gear, ball 165 is rotated counterclockwise a further 40 degrees about axis X2 using ring 61 until the ball reaches position IV.During this movement, the ball is pushed inwards by the ring 159 and locks within a groove 167 on the ring gear.

[0095] 164 and takes the ring gear with it in a counterclockwise rotation. In this area between position III and position IV, the ring 159, which functions as a frame within this stepping gear 160, has no milled recess on its link 166. For this reason, the ball moves on an inner diameter 168. In this area between position III and position IV, the three gears 152, 153, 154 are simultaneously rotated by 120 degrees by the ring gear 164. To shift from fourth gear to fifth gear, the ball

[0096] 165 is rotated a further 40 degrees counterclockwise with the help of ring 61 until the ball has reached position V. In this area, the three gears 152, 153, 154 are no longer rotated by the ring gear 164 because the ball 165 cannot drive the ring gear 164. The ball 165 is located on its outer race diameter 169. It also remains there when shifting from fifth to sixth gear and the ball 165 is rotated further counterclockwise with the help of ring 61 until the ball has reached position VI. To shift from sixth to seventh gear, the process that already took place from third to fourth gear is repeated. The ball 165 is pushed inwards by the link of the outer ring 159 within the groove 162 and engages in a recess 167. In a preferred embodiment, the recess 167 is made as a groove 167 and is located on the ring gear 164.The ring gear 164, together with the actuating gear 68, which is integrally connected to the ring 161, is rotated from position VI to position VII. To shift from seventh gear to eighth gear, the ball 165 is rotated counterclockwise by a further 40 degrees around the axis X2 with the aid of the ring 61 until the ball reaches position VIII. In this area, the ring gear 164 is again not rotated. The ball 165 slides within the link 166, which is located as a milled recess on the inside of the ring 161. To shift from eighth gear to ninth gear, the ball 165 is rotated counterclockwise by a further 40 degrees around the axis X2 with the aid of the ring 61 until the ball reaches position IX. Even during this movement, only the pivotable supports 64, 65, 66 are rotated in the axial bores by the actuating gear 68.The pivotable supports 61, 62, 63, which are connected to the gears 152, 153, 154, are not rotated during this movement. This indexing gear 160 in this preferred embodiment moves exclusively within a range of 320 degrees. A complete rotation is not desired in this exemplary embodiment. The movement can be clockwise or counterclockwise. A clockwise rotation corresponds to the switching movements from a high gear to a lower gear. The mode of operation works in both directions of rotation. It can also be seen in Figure 13b that the axial bores in which the pivotable supports are arranged are evenly spaced on a pitch circle on the lateral axial flat surface of the selector shaft, and the pitch circle is arranged concentrically to the rotational axis X2 of the selector shaft 67.

[0097] Figure 14 shows a schematic representation of the step-by-step gear mechanism 160 coupled to the selector shaft 67 in conjunction with the actuating assembly 85. All actuating means are located within the actuating assembly 85. The right-hand part of the selector shaft 67 and the right-hand ball bearing 32' are also shown cut away in the illustration. As already explained above, the state of the three clutch means K1, K2, K3 is only changed between the third and fourth gear and between the sixth and seventh gear via the step-by-step gear mechanism 160. The actuating gear 68 actuates the clutch means K4, K5, K6 directly on the one hand and the clutch means K1, K2, K3 via the ring gear 164. When the cyclist pedals while riding, the bottom bracket shaft 67 rotates continuously around the rotation axis X2.If no switching movement is carried out during this travel, the entire stepping gear 160 with the reference gear 69 and the actuating gear 68 rotates at the same speed as the switching shaft 67. In an advantageous embodiment, the rotation axis X2 of the switching shaft 67 is coaxial with the rotation axis X11 of the stepping gear 160 and the stepping gear 160 is located at least to a large extent laterally next to the switching shaft 67 and next to the ball bearing 32' of the switching shaft 67. In this case, the switching shaft 67 is preferably connected to a reference gear 69 with external teeth, which has a larger diameter compared to the outer diameter of the switching shaft 67 and wherein the stepping gear 160 has an actuating gear 68 with external teeth that has a similar or identical diameter to the reference gear 69.As already described above, the shifting process is initiated by rotating the actuating gear relative to the reference gear 69. This shifting process must also function when the shift shaft is rotating. With the help of the superposition gear 170, which is parallel and not coaxial to the shift shaft, the actuating gear 68 can be rotated relative to the reference gear 69 from a stationary housing 121.

[0098] The superposition gear 170 according to the invention has a sun gear 173, which is arranged in a rotationally fixed manner on a housing 180. This connection can also be made indirectly. An actuating sun gear 174 is mounted coaxially to this fixed sun gear 173 in the housing 180. Both sun gears 173, 174 mesh with planet gears 176. Preferably, both sun gears 173, 174 have the same diameter, and in a preferred embodiment, all planet gears 176, 176', 176", 176"' also have the same diameter. The planet gears 176, 176', 176", 176'" are mounted on the carrier 175 via planet gear axles 179. The planetary gears 176, 176', 176", 176'" are preferably in contact with two internal gears 182, 182'. In an advantageous embodiment, the first internal gear 182 is located within a concentric bore of an externally toothed reference gear 177 of the superposition gear.In an advantageous embodiment, the second internal toothing 182' is located within a concentric bore of an externally toothed actuating wheel 178 of the superimposed gearing. The actuating wheel 178 of the superimposed gearing 170 is constantly engaged with the actuating gear 68 of the stepping gear 160. The reference wheel 177 of the superimposed gearing 170 is constantly engaged with the reference gear 69 of the stepping gear 160. When the cyclist pedals while riding, the bottom bracket shaft 67 continuously rotates around the rotation axis X2. If no switching movement is performed during this travel, the entire stepping gear 160 with the reference gear 69 and the actuating gear 68 rotates at the same speed as the switching shaft 67. Consequently, the reference gear 177 of the superposition gear 170 and the actuating gear 178 of the superposition gear 170 also rotate continuously during operation.Since the sun gear 173 is fixed to the housing, the web also rotates about the axis X10. The actuating sun gear 174 remains stationary in relation to the housing 180 during operation. If an actuating torque MBT is introduced at an actuating interface 181, this rotational movement leads to a relative rotation of the actuating gear 68 in relation to the reference gear 69. Actuation is also possible while the selector shaft 67 is rotating. The torque flow that occurs during actuation of the gearshift is schematically shown in Figure 14 as a thick black line. In this exemplary embodiment, an electric servomotor 183 is arranged at the actuating interface 181 via a reduction gear 184. In this way, high torques can be fed into the actuating interface 181 to enable shifting under load on the bottom bracket gear.Considering the entire actuation assembly 85 within the novel bottom bracket shift, the torques are generated by the electric servomotor 183, amplified by the reduction gear 184, fed into a rotating system within the superposition gear 170, divided into several load paths within the step-change gear 160, and fed into the clutch means K1 to K6. This enables the clutch means to connect the individual idler gears to the shift shaft in the correct sequence. In other embodiments, not only an electrically operated actuator 172 can perform the shifting operation at the actuation interface 181, but simple and cost-effective control via a cable pull, hydraulics, or other state-of-the-art actuations are also possible.In order to sense absolutely or incrementally which gear is engaged during operation of the bottom bracket shifting system, a sensor assembly 171 for gear detection is preferably arranged within the actuation assembly 85 near the actuation interface 181. This assembly consists of a gear 187, which receives the rotation angle information near the actuation interface 181 and forwards it to the sensor assembly 171. In an advantageous embodiment, a further gear ratio 186 is arranged behind the gear 187 in order to better process the angle information for the electronic position sensor.

[0099] The exemplary descriptions within the illustrations in Figures 1 to 14 make it clear that the above-described problems of integrating an advantageous bottom bracket gearshift into an electric bicycle with auxiliary drive, in particular in the form of a mid-engine, are solved with the aid of the novel sensor arrangement 123. In the advantageous embodiment, the sensor arrangement 123 is connected in a novel functional and spatial manner to the likewise novel coupling and actuating means 85. This requires a very small and narrow sensor arrangement 123 and the novel design and positioning of the coupling means K and actuating means 85 in order to overcome the disadvantages of the prior art within the available installation space.

[0100] Reference symbol

[0101] Frame

[0102] top tube

[0103] down tube

[0104] seat tube

[0105] battery

[0106] Pedals

[0107] Crank arm, cranks front pulley

[0108] bracket

[0109] bottom bracket gearshift, bottom bracket gear, gear unit

[0110] Control element

[0111] Traction devices, belts

[0112] rear wheel

[0113] swingarm

[0114] Front wheel suspension

[0115] Rear suspension

[0116] Swing arm bearing

[0117] bottom bracket spindle

[0118] axis of rotation of the rear wheel

[0119] Belt tensioner

[0120] Mounting plates

[0121] Housing

[0122] Tension pulley left protective cap left protective cap shift shaft

[0123] Bearing axis fixing screw

[0124] Needle bearing

[0125] Spacer sleeve 29 shaft nut

[0126] 30 abortionists

[0127] 31 Shaft seal

[0128] 32 32', 32" ball bearings

[0129] 33 Retaining ring

[0130] 34 Gearbox housing right

[0131] 35 Gearbox housing left

[0132] 36 Output hollow shaft toothed

[0133] 37 20 teeth output gear

[0134] 38 32 teeth output gear

[0135] 39 26 teeth output gear

[0136] 40 spring

[0137] 41 20 tooth drive gear

[0138] 42 32 teeth drive gear

[0139] 43 53 teeth drive gear

[0140] 44 rotating circuit board

[0141] 45 PCB fixed to the housing

[0142] 46 Bottom bracket freewheel movable

[0143] 47 bottom bracket freewheel rigid

[0144] 48 plain bearings

[0145] 49 Screw connection circuit board rotating

[0146] 50 Screw connection board fixed to the housing

[0147] 51 idler gear with 15 teeth

[0148] 52 idler gear with 17 teeth

[0149] 53 idler gear with 20 teeth

[0150] 54 idler gear with 20 teeth

[0151] 55 idler gear with 21 teeth

[0152] 56 idler gear with 21 teeth

[0153] 57 Internal gearing clutch

[0154] 58 Coupling body strain gauge / sensor

[0155] Input hollow shaft pivoting support of the clutch means K1 pivoting support of the clutch means K2 pivoting support of the clutch means K3 pivoting support of the clutch means K4 pivoting support of the clutch means K5 pivoting support of the clutch means K6 selector shaft

[0156] Actuating gear shift shaft

[0157] Reference gear shift shaft

[0158] stepping gear

[0159] Internal toothing ring gear

[0160] Oil filling

[0161] Plug-in toothing first gear stage, first partial gear second gear stage, second partial gear lateral plane surface of the gear electronic components materially bonded ring

[0162] Pinion, small gear, spring-loaded pressure piece, right side cover

[0163] Fixing screws for electric drive assembly

[0164] Manual transmission assembly

[0165] Actuating assembly right outer cover

[0166] Gear with 15 teeth

[0167] Gear with 30 teeth Gear with 21 teeth

[0168] Gear with 14 teeth

[0169] Gear with 12 teeth

[0170] Gear with 55 teeth

[0171] Power electronics with direct phase connection

[0172] Chamber, room for electronics, dry

[0173] Section with view of first reduction level

[0174] Plug contacts

[0175] Freewheel

[0176] 98' step gear housing-fixed axle

[0177] Shaft electric motor lateral web between teeth electric auxiliary drive, electric motor

[0178] Mounting points electronic board with sensor elements

[0179] ,105', 105 " wave collar

[0180] Worm spring, tension spring, annular spiral spring

[0181] Recess in the lateral surface, pocket

[0182] sliding disc

[0183] idler gear

[0184] Pressure surfaces of the internal gearing

[0185] Sliding surfaces of the internal gearing

[0186] Bearing surfaces of the internal gearing axial bores pivoting support

[0187] Back of the coupling body

[0188] Pressure surface of the coupling body

[0189] Spring mounting surface, spring support surface spring

[0190] opening

[0191] ,120', 120" wave collar

[0192] Gearbox housing

[0193] Output shaft

[0194] Sensor arrangement

[0195] Force from the idler gear to the clutch body (Fk)

[0196] Support force of the coupling body on the pivoting support (Fb)

[0197] Actuating torque Mb

[0198] Lever arm on the pivoting support

[0199] Lever arm Ik on the coupling body 58

[0200] Lever arm Ib on the coupling body 58

[0201] Lever arm Ish on the self-locking coupling body

[0202] Support force Fr on the self-locking coupling body

[0203] Lever arm Ir on the self-locking coupling body

[0204] Camshaft actuation torque Mn

[0205] Lever arm Ln on the camshaft

[0206] Lever arm lar on the self-locking coupling body

[0207] Actuating force Far

[0208] Bearing surface of the clutch body on the selector shaft

[0209] camshaft

[0210] Bearing surface of the pivoting support on the selector shaft

[0211] Bearing force of the clutch body on the selector shaft (Fa) self-locking clutch body

[0212] Grooves on the lateral surface

[0213] Chambers for pivoting supports

[0214] Coupling body of the coupling agent K1

[0215] Coupling body of the coupling agent K2

[0216] Coupling body of the coupling means K3 Coupling body of the coupling means K4

[0217] Coupling body of the coupling agent K5

[0218] Coupling body of the coupling agent K6

[0219] Recesses on the outer surface of the pivoting supports

[0220] Shell surface of the pivoting supports

[0221] Gear for actuating the clutch means K1

[0222] Gear for actuating the clutch means K2

[0223] Gear for actuating the clutch K3

[0224] Gear for actuating the clutch means K4

[0225] Gear for actuating the clutch K5

[0226] Gear for actuating the clutch means K6

[0227] Countersink, deepening short cylindrical ring on the reference gear

[0228] Indexing gear short cylindrical ring on the reference gear

[0229] Groove, sliding track for ball

[0230] Internal gearing on the ring gear; output of the indexing gear

[0231] Ring gear for actuating the clutch means K1, K2, K3

[0232] Ball of the stepping gear

[0233] Gate on the inner surface of the ring on the actuating gear

[0234] Groove or recess on the ring gear of the indexing gear inner raceway of the ball, inner diameter outer raceway of the ball, outer diameter

[0235] Superposition gear

[0236] Sensor assembly for gear step detection

[0237] Actuator, actuator assembly, servo motor assembly with gearbox, housing-fixed sun gear of the superposition gear, actuated sun gear on the superposition gear

[0238] Web of the superposition gear

[0239] Planets of the superposition gear 177 Reference gear of the superposition gear

[0240] 178 Actuating wheel of the superposition gear

[0241] 179 planetary gear axles

[0242] 180 housings

[0243] 181 Actuation interface

[0244] 182 182' Internal gearing on the superposition gear

[0245] 183 electric actuator

[0246] 184 Reduction gear on the actuator

[0247] 185 electronic position sensor

[0248] 186 Gear ratio at the position sensor

[0249] 187 Gear on the position sensor

[0250] X1 Rotation axis bottom bracket spindle

[0251] X2 Rotation axis switching shaft

[0252] X3 rotation axis electric motor

[0253] X4 Rotation axis input shaft actuator; rotation

[0254] X5 rotation axis reduction gear

[0255] X6 rotation axis reducer

[0256] X7 rotation axis reduction gear

[0257] X8 rotation axis coupling body

[0258] X9 rotation axis swivel support

[0259] X10 rotation axis superposition gear

[0260] X11 Rotation axis indexing gear

[0261] K1 Coupling agent 1

[0262] K2 Coupling agent 2

[0263] K3 Coupling agent 3

[0264] K4 Coupling agent 4

[0265] K5 Coupling agent 5

[0266] K6 Coupling agent 6 E1 Level 1

[0267] A1 Excerpt A1

[0268] Ma resulting torque on the coupling body

[0269] Mp self-locking torque on the coupling body

[0270] Mbt actuation torque at the actuation interface

[0271] K The coupling agents, assembly of all coupling agents

Claims

Claims: Bottom bracket shift (10), in particular for a muscle-powered vehicle with an electric auxiliary drive, comprising a sensor arrangement (123), a gearbox housing (34, 35) consisting of housing parts (34) and (35), a bottom bracket shaft (18) mounted in the gearbox housing (34, 35), an output shaft (122), at least one partial gearbox (74) in the gearbox housing (34, 35), wherein the at least one partial gearbox (74) has at least one shift shaft (67) on which at least two gear stages can be set, and at least one of at least two circuit boards (44, 45) which is connected directly or indirectly to the bottom bracket shaft (18) or the output shaft (122). Bottom bracket shifting system (10) according to claim 1, with a second of the at least two circuit boards (44, 45) which is directly or indirectly connected to at least a part of the gearbox housing (34, 35) of the bottom bracket shifting system (10).Bottom bracket circuit (10) according to claims 1 and 2, wherein electronic components (77) are located on two of the at least two circuit boards (44, 45), which transmit at least one signal that is representative of the torque or rotational speed applied to the bottom bracket axle (18) or the output shaft (122). Bottom bracket circuit (10) according to any one of claims 1 to 3, wherein the surface of at least one of the at least two circuit boards (44, 45) is perpendicular to an axis of rotation of the bottom bracket axle (18) or the output shaft (122). Bottom bracket circuit (10) according to any one of claims 2 to 4, wherein the surfaces of the at least two circuit boards (44, 45) on which electronic components (77) are located are arranged coplanarly to each other. Bottom bracket shifter (10) according to one of claims 2 to 5, wherein the at least two circuit boards (44, 45) are located in close proximity to each other. Bottom bracket gear unit (10) according to any one of claims 1 to 6, wherein the bottom bracket shaft (18) is connected directly or indirectly to the first of the at least two plates (44, 45). Bottom bracket gear unit (10) according to any one of claims 1 to 7, wherein the bottom bracket shaft (18) is connected directly or indirectly to an input hollow shaft (60) which is located coaxially to the bottom bracket shaft (18), wherein the input hollow shaft (60) is connected coaxially to at least two drive gears (42, 43), and wherein the first of at least two plates (44, 45) is attached to a drive gear or the input hollow shaft (60). Bottom bracket gear unit (10) according to claim 8, wherein a freewheel is arranged between the bottom bracket shaft (18) and the input hollow shaft (60). Bottom bracket shifter (10) according to one of claims 2 to 9, wherein the first of the at least two circuit boards (44, 45) wirelessly exchanges signals with the second of the at least two circuit boards (44, 45).Bottom bracket circuit (10) according to any one of claims 2 to 10, wherein electrical energy is inductively transferred from the second circuit board (44, 45), which is connected to a housing part (34) or (35), to the circuit board (44, 45), which is directly or indirectly connected to the bottom bracket shaft (18) and the input hollow shaft (60). Bottom bracket circuit (10) according to any one of claims 2 to 11, wherein the bottom bracket circuit (10) has an output hollow shaft (36) to which a pulley (8) or chainring for a traction element (12) extending to a rear wheel (13) of the electric bicycle can be attached, and wherein the bottom bracket shaft (18) runs coaxially in the output hollow shaft (36) and wherein the at least two circuit boards (44, 45) are arranged axially to the right or left of the output hollow shaft (36).Bottom bracket shifter (10) according to any one of claims 2 to 12, wherein the input hollow shaft (60) and the output hollow shaft (36) are arranged side by side on the bottom bracket shaft (6), and wherein the at least two plates (44, 45) are arranged centrally between the input hollow shaft (60) and the output hollow shaft (36). Bottom bracket shifter (10) according to any one of claims 1 to 13, with a gearbox housing (34, 35) in which the shifting gear (84) and the bottom bracket shaft (18) are accommodated. which is designed to accommodate the electric auxiliary drive (102) and / or the actuating assembly (85) and / or an electric drive assembly (83), wherein only one of the at least two circuit boards (44, 45) is fixedly connected to the housing. Bottom bracket shifter (10) according to claim 14, wherein the at least two circuit boards (44, 45) are housed in the housing part (34) or (35) of the gearbox housing (34, 35) in which the shifting gear (84) runs in an oil bath. Bottom bracket shifter (10) according to any one of claims 3 to 15, wherein the surfaces of the at least two circuit boards (44, 45) on which electronic components (77) are located are located no more than eight millimeters apart. Bottom bracket shifter (10) according to any one of claims 2 to 16, wherein the at least two circuit boards (44, 45) rotate relative to each other during operation and never touch each other.Bottom bracket shifter (10) according to one of claims 1 to 17, comprising a first sub-gearbox (74) and a second sub-gearbox (75) connected in series for power transmission, wherein the first sub-gearbox (74) and the second sub-gearbox (75) have a shift shaft (67) on which a plurality of loose gears (51, 52, 53, 54, 55, 56) are mounted, which together with a corresponding plurality of drive gears (41, 42, 43) and driven gears (37, 38, 39) form gear pairs of the respective sub-gearbox, wherein the loose gears (51, 52, 53, 54, 55, 56) can be connected to the shift shaft (67) by means of coupling means (K1, K2, K3, K4, K5, K6). Bottom bracket gear shift (10) according to claim 18, wherein the at least two circuit boards (44, 45) are located centrally between the first partial gear shift (74) and the second partial gear shift (75).Bottom bracket shifter (10) according to one of claims 1 to 19, wherein the bottom bracket shifter (10) has an electric auxiliary drive (102) and wherein a power flow from the electric auxiliary drive (102) and a power flow from the bottom bracket shaft (18) are superimposed before or inside the first partial drive unit (74) or before or inside the second partial drive unit (75) and wherein at least one of the at least two circuit boards (44, 45) detects a signal via a sensor which represents at least a part of the power flow. Bottom bracket shifter (10) according to any one of claims 2 to 20, wherein components are arranged on the second of the at least two circuit boards (44, 45), which is directly or indirectly connected to the gearbox housing (34, 35), which carry the signal, representative of the torque or speed, out of the gearbox housing (34, 35). Bottom bracket shifter (10) according to claim 21, wherein the signals, representative of the torque or speed, are transmitted via one or more cables and wherein the cables are guided through an opening in the gearbox housing (34, 35), the housing opening with cable passage being designed such that no oil can pass through this opening. Bottom bracket shifter (10) according to any one of claims 18 to 22, wherein at least two of the drive gears (41, 42, 43) are manufactured from a single piece.Bottom bracket gear shift (10) according to one of claims 18 to 22, wherein at least two of the output gears (37, 38, 39) are made from a single piece.

Images