EP4323264A1

EP4323264A1 - Bicycle bottom bracket transmission with clutch devices which are coupled together

Info

Publication number: EP4323264A1
Application number: EP22718918.0A
Authority: EP
Inventors: Karlheinz Nicolai
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-04-13
Filing date: 2022-03-29
Publication date: 2024-02-21
Also published as: WO2022218683A1; DE102021109207A1

Abstract

A bicycle bottom bracket transmission (1), having at least one transmission shaft (3, 5, 7) on which gear wheels (27, 34) coupled to one shiftable clutch device (29) each are arranged. The clutch devices can be shifted between an engaged state (31) and a disengaged state (33). In the engaged state, a clutch device connects the gear wheel coupled to it to the respective transmission shaft (3, 5, 7) for conjoint rotation in at least one direction of rotation of the respective transmission shaft, and, in the disengaged state of the clutch device, the gear wheel is freely rotatable in relation to the respective transmission shaft. At least one shifting device (35, 37) is provided for shifting the clutch devices of a transmission shaft. Each transmission shaft, on which gear wheels coupled to one shiftable clutch device each are arranged, is assigned another shifting device here. Each shifting device has at least two shifting positions (39, 41, 101) and can be transferred from one of the shifting positions into another of the shifting positions by means of a shifting movement (38, 45). Each of the shifting positions of a shifting device corresponds to a different combination of the engaged and disengaged states of the clutch devices of the transmission shaft assigned to it. During each shifting movement, at least one of the clutch devices arranged on the transmission shaft assigned to a shifting device is engaged.

Description

Bicycle bottom bracket gear with coupled coupling devices

The invention relates to a bicycle bottom bracket gear. Bicycle bottom bracket gears are known and are increasingly being used in bicycles and electrically assisted bicycles, so-called pedelecs. The bicycle bottom bracket gearbox, which is used as a gear shifter or in addition to the gear shifter of a bicycle, has advantages over other types of bicycle gears.

Derailleur gears or hub gears are usually used on bicycles and pedelecs. In the case of pedelecs in particular because there is not enough space available at the bottom bracket. However, derailleur gears are disadvantageous in that the components of the gear shift, namely the pinion on the rear wheel hub, the at least one chain ring and the chain together with the derailleur are unprotected and therefore easily soiled. A derailleur is therefore comparatively high-maintenance.

Hub gears are used instead of or in conjunction with derailleur gears on the rear wheel. The hub gears are isolated from the outside environment in a housing and are therefore largely maintenance-free. However, the disadvantage of hub gears is the high weight on the rear wheel, which leads to an unfavorable weight distribution. The high weight on the rear wheel hub is not only annoying when carrying it, but also when cornering or when driving off-road.

A much more advantageous weight distribution results when the gear shift is positioned in the middle of the bike, as is the case with bottom bracket shifters, for example.

Bicycle bottom bracket circuits also have the advantage that they can be accommodated together with an electric motor in the same housing and therefore allow a compact design for an electrically assisted bicycle. A bicycle bottom bracket gear of the applicant is known for example from DE 102004045364 B4. A disadvantage in conventional bicycle bottom bracket gears can be perceived as an increased noise level compared to other types of shifting and/or a gear change that does not take place smoothly. In addition, some bicycle bottom bracket gears cannot be shifted under load or can only be shifted with difficulty. There is therefore a need for compact and easy-to-switch bicycle radtretlagertriebe, which can also be used with electric drives. The aim of the present invention is to create such a bicycle bottom bracket gear. Specifically, the invention relates to a bicycle bottom bracket gear, with at least one gear shaft on which gears are arranged, each coupled to a switchable clutch device, the clutch devices being designed to be switchable between an engaged state and a disengaged state, with a clutch device in the engaged state the one coupled to it gear wheel in at least one direction of rotation of the respective gear shaft with the respective gear shaft in a rotationally fixed manner and in the disengaged state of the clutch device the gear wheel can rotate freely relative to the respective gear shaft, with at least one switching device for switching the clutch devices of a gear shaft, with each gear shaft, on the with in each case a switchable clutch device coupled gears are arranged, another switching device is assigned, each switching device aufwei at least two switching positions st and is designed such that it can be transferred from one of the switching positions to another of the switching positions by means of a shifting movement, each of the shifting positions of a shifting device corresponding to a different combination of the engaged and disengaged states of the clutch devices of the transmission shaft assigned to it, with during each shifting movement at least one of the clutch devices which are arranged on the transmission shaft assigned to a switching device, is engaged, and wherein the at least one transmission shaft is at least one transmission shaft from the group containing an input shaft of the bicycle pedal bearing transmission, an output shaft of the bicycle pedal bearing transmission and at least one intermediate shaft of the bicycle pedal bearing transmission.

By coupling at least two switchable clutch devices of a transmission shaft by the associated switching device, it is possible to switch in a well-defined manner between the gears that are connected to the transmission shaft in a rotationally fixed manner. In particular, there is no need for a gear change to take place solely through the automatic intervention of a freewheel on the transmission shaft. The precise shifting enables a smooth gear change. This type of shifting also makes it possible to do without passive, i.e. not actively switchable, freewheels on the transmission shaft, which are often used in transmissions. The omission of such an additional freewheel reduces the operating noise and the production costs.

Because at least one clutch device is engaged during a shifting movement, slipping during shifting can be avoided. The fact that, starting from any shift position, any other shift position can be reached with just one rotary movement, rapid gear changes are possible. The invention can be further improved by means of the configurations described below. The individual configurations are advantageous independently of one another and can be combined with one another as desired.

Thus, according to a first further development, starting from one of the switching positions of a switching device, each other of the switching positions of this switching device can be reached by exactly one switching movement.

According to a further refinement, the input shaft can be designed so that it can be connected directly or indirectly to a set of pedal cranks. The input shaft can, for example, run coaxially with the bottom bracket shaft and be connected to it, for example, via a freewheel. The input shaft can also run parallel to the bottom bracket shaft and in particular can be connected to the bottom bracket shaft with a gear reduction.

The output shaft can be designed to be connected directly or indirectly to a drive pinion. The drive sprocket can be a sprocket, a set of sprockets, or a toothed belt pulley. The output shaft can also be arranged parallel to a shaft directly supporting the drive pinion.

A shift position is preferably present when the clutch devices switched over by a shift device are all fully engaged or disengaged. In the transition between the shift positions, in the shifting movement, the clutch devices are engaged or disengaged. In order to achieve a well-defined power flow between the input shaft and the output shaft, one gear is preferably always engaged when shifting the gears of a transmission shaft and the other gears of this transmission shaft are simultaneously disengaged or left in the disengaged state. This can be done by coupling the switchable clutch devices via the switching device. The at least one transmission shaft of the bicycle pedal bearing transmission is preferably mounted in a stationary manner in a transmission housing, in which further transmission shafts can also be mounted in a stationary manner. The transmission housing can be filled, at least partially, with a lubricant. The gear housing can enclose a motor, in particular an electric motor, which is coupled in a force-transmitting manner to the bicycle bottom bracket gear. Each different combination of switching positions of the existing switching devices, ie each different combination of engaged and disengaged clutch devices corresponds to a gear of the bicycle bottom bracket transmission.

According to a further advantageous embodiment, at least two transmission shafts can be present instead of the at least one transmission shaft and at least two shifting devices for shifting the clutch devices to one of the at least two transmission shafts instead of the at least one shifting device. Gear wheels coupled to a respective clutch device are arranged as described above on each transmission shaft. Each switching device preferentially switches the clutch devices of another transmission shaft.

Each gear of one and the same gear shaft, which is in engagement with the gear of another gear shaft of the Ge bicycle bottom bracket gear, preferably has a coupling device. In this embodiment, the coupling devices are only arranged on one of two shafts and only one shifting device is required, which simplifies the construction of the bicycle bottom bracket gear.

At least two gears can be arranged on the input shaft, the output shaft and the at least one intermediate shaft, each of which meshes with at least one of the gears of another transmission shaft.

A particularly advantageous embodiment of the Fahrradtretlagertriebs can be obtained when the shifting movement is a rotary movement, each gear of Fahrradtretla gertriebs can be reached within a full revolution of all switching devices. This configuration allows a very quick gear change to take place. As a result, it may be superfluous to switch through all the gears that are possible with the bicycle bottom bracket gear one after the other. A switching position of a switching device does not have to be limited to a punctiform area of the rotary movement. In order to achieve smooth gear changes, a shift position can extend over an (angular) range of rotary movement. The range can be greater than 10° and less than 90°. The at least two switching devices are particularly preferably designed to assume their respective switching positions independently of one another. As a result, a faster gear change can take place. The two switching devices are particularly preferably designed to switch at the same time. As described above, the switching devices can preferably be actuated independently of one another. In particular, if these are actuated simultaneously and/or the switching movements are synchronized with different switching devices, a gear change can follow very quickly. In order to actuate both switching devices simultaneously and independently of one another, each of the switching devices can have an actuator for generating the switching movement, in particular a rotary movement.

An actuator can be mechanical, for example. A mechanical actuator can be formed, for example, as a twist grip or shift lever, which is designed to generate the shifting movement of the shifting device.

However, each of the two switching devices is preferably provided with an electrical actuator which can generate the switching movement. The electric actuator can in particular be an electric motor, for example a stepping motor. The electrical actuators can be remotely controlled by suitable means. For example, a bicycle provided with the bicycle bottom bracket gear can be provided with control elements which are connected to the actuators in a data-transmitting manner. By selecting a desired gear, both actuators can be activated at the same time, so that both switching devices can change their switching positions and set the desired gear at the same time.

A shifting device of simple construction can be obtained in that each shifting device assigned to a transmission shaft has a rotatable shifting shaft and is designed such that when the shifting shaft rotates about its axis, a different one of the shiftable clutch devices of that transmission shaft to which this shifting device is assigned is successively activated , to switch at least from the engaged state to the disengaged state. In other words, the selector shaft executes the shifting movement of the shifting device as a rotary movement.

The at least one selector shaft is preferably arranged parallel to the transmission shafts, in particular in the transmission housing. Preferably, all switching positions of this switching device can be reached within a full revolution of a switching shaft. In order to be able to control the individual shiftable clutch devices safely and precisely, each shifting device assigned to a transmission shaft can comprise a shifting yoke which is held axially displaceably on the shifting shaft and which is connected to a clutch body of the respective clutch device is connected in a shifting movement-transmitting manner. The shifting yoke can preferably interact with the clutch body at two diametrically opposite sills of the clutch body, in order to prevent the clutch body from tilting on the transmission shaft. Each switching yoke is preferably arranged such that it can interact with the respective switchable clutch device in such a way that it can move the clutch device at least from the engaged state to the disengaged state.

In order to move the shifting yoke on the shifting shaft so that this in turn can move the clutch body, the shifting yoke is preferably provided with at least one shifting cam and the shifting shaft with at least one shifting gate for the shifting cam. As an alternative to this, the shifting yoke can be provided with a shifting gate and the selector shaft with a shifting cam for the shifting gate. A surface, in particular a planar surface of the shift gate preferably has two positions spaced apart from one another in the axial direction, which are associated with the engaged and the disengaged state. The surface extends continuously over the two positions and is formed accordingly increasing or decreasing.

In order to guide the at least one shifting yoke safely and to prevent the shifting yoke from tipping or canting, in particular when shifting under load, the at least one shifting yoke is preferably held displaceably at two axially spaced bearing points on the shifting shaft and the shifting gate and the shifting cam are , In particular in the axial direction, arranged between the two bearing points.

Preferably, at least one of the switchable clutch devices has a pressing device and a clutch body that is functionally coupled to the pressing device, the pressing device being designed to move the clutch body into engagement with the gear wheel belonging to this clutch device, the pressing device having at least one axially immovable the transmission shaft arranged abutment and at least one arranged between the abutment and the coupling body spring element. The spring element can in particular be a compression spring. The aforementioned embodiment makes it possible for the shiftable clutch device to preferably assume the engaged state if it is released for this purpose by the shifting device, for example because the switching yoke does not pull the clutch body away from the gear wheel and does not stand in the way of movement by the pressing device.

In order to ensure a secure connection between the clutch body and the associated gear, the pressing device preferably has a plurality of spring elements which are spaced apart from one another in a circumferential direction of the transmission shaft between the we least one abutment and the clutch body. The spring elements are particularly preferably arranged equidistant from one another. If there is an even number of spring elements, they can be diametrically opposed across the transmission shaft.

If the clutch body is engaged with the associated gear wheel, this gear wheel is non-rotatably connected to the transmission shaft.

In order to prevent the bicycle bottom bracket from driving the pedal crank set, for example when driving fast, at least one, particularly preferably each, of the switchable clutch devices is designed as a disengageable freewheel.

A freewheel that can be reliably disengaged can be obtained in that this, or the switchable clutch device designed as a disengageable freewheel, has two face-toothed toothed discs. The toothed discs can be provided with saw-toothed teeth. The two face-toothed pulleys are separated from each other when the clutch is disengaged. In the coupled state, on the other hand, these are arranged in a force-transmitting manner that engages in one another. In this case, one of the two toothed disks is preferably held on the transmission shaft in a rotationally fixed but axially displaceable manner. This toothed disc can, for example, be non-rotatably connected to the hitch be body or formed in one piece with it. The other toothed disk is connected to the gear wheel, which is to be connected to the transmission shaft in a rotationally fixed manner by the switchable clutch device. This toothed disc can be formed in one piece with the gear wheel. In the disengaged state of the respective coupling device, the toothed disks are separated from one another and, in the engaged state, are pressed against one another by spring force, in particular exclusively by spring force.

If all shiftable clutch devices are designed as disengageable freewheels, noise can be avoided and the transmission can be prevented from jamming or locking when shifting. In order to prevent unintentional disengagement of the engagement of the two toothed discs with one another, one end of the switching yoke on the side of the clutch body is preferably accommodated with play in the clutch body. In other words, the shifting yoke does not exert any force on the clutch body in the engaged state. The intermediate shaft is preferably arranged between the input shaft and the output shaft. According to a further advantageous embodiment, the at least one intermediate shaft can have more gears than the input shaft and/or the output shaft. The intermediate shaft preferably has fewer than twice the number of gears than the input and/or the output shaft. The input and output shafts preferably have the same number of shiftable gear wheels.

The intermediate shaft preferably has no switchable gears. As a result, the intermediate shaft can be formed monolithically with its gears.

Particularly preferably, the input shaft and the output shaft each have three gears and the intermediate shaft has five gears. Because the intermediate shaft has more gears than the input and/or output shaft, well-defined translations can be achieved between the individual shafts. This is discussed again below.

Preferably, all gears of the input shaft and all gears of the output shaft can be connected in a torque-proof manner to their respective transmission shaft via switchable clutch devices, at least the gears that are constantly engaged with a gear of another transmission shaft. As already described above, the input and output shafts each have three such gears before given to them.

Each transmission shaft can also be provided with additional gears, if necessary. For example, the input shaft can be provided with a gear which can be connected directly or indirectly to a set of pedal cranks, an electric motor or another gear stage. The output shaft can be provided with a gear, for example, which can be connected or connected directly or indirectly to a drive pinion or another gear stage.

If an electric motor is provided for support, it is preferably connected to the input shaft in a force-transmitting manner. Alternatively, the electric motor can be connected to one of the other gears. According to a further advantageous embodiment, two of the transmission shafts together have at least two pairs of meshing gears, the at least two pairs forming different transmission ratios, and at least two gears belonging to the pairs of one transmission shaft having the same number of teeth. With this configuration, both a compact structure and a well-defined distribution of the different translations can be achieved.

A compact structure can also be achieved in that bewellen with a plurality of gears and with a plurality of shift shafts in Fahrradtretlagertrieb the axes of rotation of these transmission shafts and shift shafts spanning in pairs different levels that are not parallel to each other. In other words, each pair of waves lies in a different plane and all of these planes are not parallel. This allows the transmission to be nested in one another.

The number of gears on the transmission shafts and the number of teeth on these individual gears are preferably selected in such a way that gear jumps between adjacent gears are greater than 21% and less than 25%.

An exemplary advantageous embodiment that allows such gear jumps is briefly described below. The input shaft is provided with three gear wheels, each of which can be connected to the input shaft in a torque-proof manner by means of a switchable clutch device. These three gears have 30, 52 and 76 teeth respectively. These three gears on the input shaft mesh with gears on the intermediate shaft, which each have 30, 28 and 22 teeth. The gear wheel of the intermediate shaft, which has 28 teeth, meshes with a gear wheel of the output shaft, which also has 28 teeth. The intermediate shaft also has two more gears, each with 22 teeth. These two gears mesh with two gears on the output shaft, which have 33 and 27 teeth respectively.

The embodiment described above results in a nine-gear transmission with gear increments of between 22 and 24%. The bandwidth of this gear shift is 518%, which usually covers all areas of use for bicycles.

The invention is explained in more detail below by way of example using advantageous embodiments with reference to the drawings. The combinations of features exemplified in the embodiments can in accordance with the above statements for a specific application necessary properties of the bicycle radtretlagertriebe invention be supplemented by other features. Also, also in accordance with the above statements, individual features can be omitted in the described embodiments if the effect of this feature is not important in a specific application.

The bicycle bottom bracket gear in one of the above, generally described configurations or according to an embodiment described below can be used instead of the switching gear of the bottom bracket circuit of DE 102021 101 415.8, to which full reference is hereby made. In the drawings, the same reference symbols are always used for elements with the same function and/or the same structure. The figures are not true to scale and only serve to illustrate the invention.

Show it:

1 shows a schematic representation of a bicycle bottom bracket transmission according to the invention;

2 shows a schematic sectional illustration through an exemplary embodiment of a bicycle bottom bracket transmission according to the invention;

FIG. 3 shows a detail of the bicycle bottom bracket transmission from FIG. 2; and

4 shows a schematic sectional illustration through an exemplary embodiment of part of a shifting device for a bicycle bottom bracket transmission according to the invention;

FIG. 5 shows a schematic representation of an exemplary time sequence of movements of two clutches during a shifting operation; FIG.

6 shows a schematic representation of the shifting movements of a bicycle bottom bracket gear.

The principle of the bicycle bottom bracket gear according to the invention is explained below with reference to the schematic sketch in FIG. In this case, only an example of a bicycle pedal bearing transmission is described, which has nine gears. The bicycle bottom bracket gear 1 has, at least according to a preferred embodiment, three gear shafts 3 , 5 and 7 , of which one serves as an input shaft 3 , one as an output shaft 5 and one as an intermediate shaft 7 .

The input shaft 3 can be connectable or connected in a force-transmitting manner to a pedal crank set 9 and/or to a motor 11 , in particular an electric motor. For this purpose, the input shaft 3 preferably has a gear wheel 13 which is connected to the input shaft 3 in a rotationally fixed manner. Alternatively, a set of pedal cranks 9 and/or the motor 11 can be connected to the input shaft 3 in some other way. The input shaft 3 can, for example, have receptacles for cranks of the set of pedal cranks 9 at its ends. In Fig. 1, a pedal crank 9, a motor 11 and their direct or indirect connections to the gear 13 are indicated by dashed lines.

The output shaft 5 is preferably designed to be connected in a power-transmitting manner to the rear wheel (not shown). For this purpose, the output shaft 5 can have a gear 15, which can be used as a drive pinion for a chain or a belt. Alternatively, the gear 15 can also be connected or connected directly or indirectly to a drive pinion 17 in a force-transmitting manner. This is indicated by dashed lines in FIG.

The intermediate shaft 7 is arranged between the two transmission shafts 3 and 5 in a power transmission direction 19 which runs from the input shaft 3 to the output shaft 5 .

The intermediate shaft 7 preferably runs with its axis of rotation 21 parallel to the axis of rotation 23 of the input shaft 3 and to the axis of rotation 25 of the output shaft 5. This arrangement automatically means that the input shaft 3 and the output shaft 5, or their axes of rotation 23 and 25, are parallel to one another get lost.

The transmission shafts 3, 5 and 7 are preferably spatially separated from one another and spaced apart from one another perpendicularly to their axes of rotation 21, 23 and 25. However, this is not mandatory. In the schematic representation according to FIG. 1 , the axes of rotation 21 , 23 and 25 or the shafts corresponding to the axes of rotation lie in one plane. However, this is not absolutely necessary. For example, in a very space-saving and compact configuration, the axes of rotation 21 and 23 can be in a first plane and the axes of rotation 21 and 25 can be in a second plane that is different from the first. An even more compact design is obtained when the axes of rotation 5T and 25 span a third plane and the axes of rotation 51 ^'' and 23 span a fourth plane, with the first, second, third and fourth planes not being identical. In order to construct the bicycle pedal bearing gear as nested as possible while making the best possible use of the installation space, as many of these four levels as possible should not run parallel to one another. In another embodiment, at least two of the transmission shafts 3, 5 and 7 can be arranged coaxially with one another. For example, the input shaft 3 and the output shaft 5 can be arranged coaxially with one another, with the intermediate shaft 7 being spaced apart from the other transmission shafts 3 and 5 and being able to connect them to one another in a force-transmitting manner. Both the input shaft 3 and the output shaft 5 each have three gears 27, each by means of a switchable coupling device 29 rotatably with their respective gear bewelle 3 or 5 are connected.

A switchable clutch device 29 is indicated at the top left in FIG. 1 with a dashed border. For the other gears 27, the switchable clutch devices 29 are only indicated by arrows, so as not to overload the figure.

The gears 27 are freely rotatably mounted on their respective transmission shaft 3 or 5, unless they are connected by their respective switchable Kupplungsvorrich device 29 in a rotationally fixed manner to their transmission shaft 3 or 5 . The gears 27 can be mounted on the transmission shaft 3 or 5, in particular by means of slide or roller bearings. In Fig. 1, the gear shown on the right 27 of the input shaft 3 and the right Darge presented gear 27 on the output shaft 5 in the engaged state 31 are shown. These gears 27 are thus rotatably connected by their switchable coupling devices 29 with their gear shaft 3 and 5 jewei time.

The other two gears 27 on the input shaft 3 and on the output shaft 5 are shown in the disengaged state 33 by being solved in each case by their switchable hitch be device 29 on the transmission shaft 3 and 5 freely rotatable.

The intermediate shaft 7 has a total of 5 gears 34, all of which are connected to the intermediate shaft 7 in a rotationally fixed manner. Each of the gears 27 of the input shaft 3 meshes with a gear 34 of the intermediate shaft 7 and each of the gears 27 of the output shaft 5 meshes with one of the gears 34 of the intermediate shaft 7.

Two of the gears 34 of the intermediate shaft 7 are each engaged with only one gear 27 of the input shaft 3, two gears 34 of the intermediate shaft 7 are each engaged with only one gear 27 of the output shaft 5 and one gear 34 of the intermediate shaft 7 is engaged with one gear 27 of the input shaft 3 and with a gear 27 of the output shaft 5 engaged. To control the switchable clutch devices 29, each transmission shaft, which is provided with gears 27 that can be rotationally connected to its respective transmission shaft 3 or 5 by means of switchable clutch devices 29, is assigned a switching device 35 or 37, respectively. In the bicycle bottom bracket transmission 1 shown schematically in FIG. 1, a shifting device 35 is assigned to the input shaft 3 and a shifting device 37 is assigned to the output shaft 5 .

Each of the shifting devices 35, 37 is designed to switch all shiftable coupling devices 29 of that transmission shaft 3, 5 to which the respective shifting device 35, 37 is assigned, at least from the engaged state 31 to the disengaged state 33.

The switching device 35 associated with the input shaft 3 is thus designed to switch each of the switchable clutch devices 29 of the input shaft 3 at least from the engaged state 31 into the disengaged state 33 .

The switching device 37 assigned to the output shaft 5 is designed accordingly to switch all switchable clutch devices 29 of the output shaft 5 at least from the engaged state 31 to the disengaged state 33 .

The switching device 35 has three different switching positions 39, in each switching position 39 exactly one of the switchable coupling devices 29 in the coupled state 31, and the two other switchable coupling devices 29 are in the coupled state 33. This is achieved in that all three switchable clutch devices 29 of the input shaft 3 are coupled to one another by the switching device 35 .

In other words, exactly one of the three switchable clutch devices 29 is in the engaged state 31 in each of the three switch positions 39 of the input shaft 3 and the gear wheel 27 belonging to this switchable clutch device 29 is connected to the input shaft 3 in a rotationally fixed manner. As a result, the input shaft 3 is connected to the intermediate shaft 7 in a force-transmitting manner in each switching position 39 via precisely one of its gear wheels 27 .

The same applies to the switching device 37 assigned to the output shaft 5 . The switching device 37 has three different switching positions 41 . In each of the switching positions 41, exactly one of the switchable clutch devices 29 of the output shaft 5 is in the engaged state 31. Consequently, in each switching position 41, the output shaft 5 is connected in a force-transmitting manner to the intermediate shaft 7 via precisely one of its gears 27. this will also achieved here in that all three switchable coupling devices 29 of the output shaft 5 are coupled to one another by the switching device 37 .

Since exactly one gear wheel 27 of the input shaft 3 always rotates with the input shaft 3 and exactly one gear wheel 27 of the output shaft 5 rotates with the output shaft 5, and all gear wheels 27 of the input shaft 3 and all gear wheels 27 of the input shaft 5 are each connected to a gear wheel 34 of the intermediate shaft 7 are engaged, a power transmission from the input shaft 3 to the output shaft 5 can take place in all switching positions 39 and 41 . In Fig. 1, in which a gear wheel 27 is shown on both the input shaft 3 and the output shaft 5 in a rotationally connected manner with its transmission shaft, the power flow 42 extends from the input shaft 3 to the output shaft 5 via these two gear wheels 27 The power flow 42 is indicated by a dashed line in FIG.

The combination of all switching positions in the bicycle bottom bracket gear 1, in the present example the combination of the switching positions 39 and 41, determines a gear 43 of the bicycle bottom bracket gearbox 1. Each gear 43 corresponds to a different power flow 42 through the bicycle bottom bracket gearbox 1.

Since there are three gears 27 on both the input shaft 3 and the output shaft 5, which can be connected in a torque-proof manner to the respective transmission shaft 3 or 5 by means of their shiftable coupling devices 29, the bicycle pedal bearing gear 1 shown as an example comprises a total of nine gears. The configuration of the individual gears in an advantageous embodiment of a bicycle rear bearing gear 1 are explained below with reference to FIG.

Each switching device 35 and 37 is preferably designed to change its respective switching positions 39 or 41 by means of a single switching movement 38 .

The switching movement 38 is preferably a rotary movement 45. The switching devices 35 and 37 can particularly preferably be designed in such a way that with a continuous rotary movement 45 all switching positions 39 and 41 of this switching device 35 and 37 can be assumed again and again one after the other.

Particularly preferably, all three switching positions 39 or 41 of a switching device 35 or 37 can be reached within a full rotational movement 45, ie within a full revolution. As a result, a faster gear change may be possible. In particular, all gears 43 of the Fahrradtretlagertriebs 1 within a full revolution of each of the two Schaltvorrichtun conditions 35 and 37 can be reached. In other words, each switching device 35 or 37 must perform at most one full revolution in order to reach the switching position 39 or 41 required for a specific gear 43 . This advantageous embodiment makes it possible, starting from any gear 43, to reach any other gear 43 within a single rotation of the two switching devices 35 and 37.

Both switching devices 35 and 37 are preferably designed to assume their respective switching positions 39 and 41 independently of one another. As a result, the quick gear change described above can be facilitated. It is particularly advantageous if the two switching devices 35 and 37 are designed to assume their respective switching positions 39 and 41 simultaneously and independently of one another.

As an alternative to this, the two switching devices 35 and 37 can be coupled to one another, for example by an appropriate mechanism. In this case, the various gears 43 can be switched through one after the other. Each switching device 35 or 37 preferably has a switching shaft 47 for performing the rotary movement 45 . Each switching device 35 or 37 can be provided with an actuator 49 to generate the rotary movement 45 . The actuator 49 can in particular be an electric actuator 49, for example a stepping motor. When mounted on a bicycle, both actuators 49 can be controlled by a common control device. Each selector shaft 47 is designed to switch one of the switchable clutch devices 29 of the respective transmission shaft 3 or 5 one after the other during a rotation about its axis 51, in particular from the engaged state 31 to the disengaged state 33.

Each shifting device 35 or 37 has a shifting sub-unit 53 for each of the switchable clutch devices 29 of that transmission shaft 3 or 5 to which this shifting device 3 or 5 is assigned. Consequently, each switching device 35 or 37 has three switching subunits 53 .

Each switching sub-unit 53 comprises a switching yoke 55, a switching cam 57 and a switching gear 59 for the switching cam 57. These are indicated only schematically in FIG. 1 and are described in more detail later with reference to FIG. The design of a switching subunit 53 is briefly discussed below, with the description preferably applying to each of the switching subunits 53 . The surface of Schaltku lisse 59, which can interact with the switching cam 47, is configured in the direction of the axis 51 of the switching shaft 47 alternately up and down or forward and set back. The shift gate 59 is preferably connected in a rotationally fixed manner to the shift shaft 47 and runs around it in a circumferential direction. The switching cam 57 is preferably connected to the switching yoke 55 or formed in one piece with it. Alternatively, a switching cam 57 can be connected in a rotationally fixed manner to the selector shaft 47 and a shifting gate 59 to the shifting yoke 55 .

The switching yoke 55 is preferably held on the switching shaft 47 so that it can be displaced along the axial direction, ie along the axis 51 thereof. The switching yoke 55 is connected to a Kupplungskör by 61 of that switchable clutch device 27 which transmits the switching movement and which is associated with this switching sub-unit 53 . A rotation of the switching shaft 47 can therefore lead to a displacement of a switching yoke 55 along the axis 51 .

A rotation of the selector shaft 47 leads to the simultaneous rotation of all shift gates 59 belonging to this selector shaft 47 . The shift cams 57 slide on the rotating shift gates 59 and are guided in the axial direction according to the shape of the shift gates 59 . The configuration of the three shifting gates 59 of a shifting shaft 47 ensures that in each shifting position 39 or 41 exactly one shifting yoke 55 of this shifting shaft 47 switches the associated shiftable clutch device 29 into the engaged state 31 . In other words, two switchable clutch devices 29 are switched into the disengaged state 33 by two switching yokes 55 of this switching shaft 47 . It may also be possible that one of these two switchable clutch devices 29 was already in the disengaged state 33 and, even when the selector shaft 47 rotates, remains in this state. The switchable clutch devices 29 are preferably each formed as a disengageable freewheel 63, with the clutch being disengaged by the clutch device 29 that can be switched with it. The configuration as a freewheel 63 makes sense in order to prevent the pedals of the bicycle from turning automatically, for example when the output shaft 5 drives the input shaft 3 . In general, a disengageable freewheel 63 has two states, the engaged state 31 and the disengaged state 33: In the disengaged state 33, the transmission shaft 3, 5, 7 carrying the freewheel 63 can rotate freely relative to the drive pinion 17 in any direction of rotation and no torque can be transmitted to the drive pinion 17. In the coupled state 31, the transmission shaft 3, 5, 7 carrying the freewheel 63 can transmit torque to the drive pinion 17 in one direction of rotation and only run freely in the other direction of rotation and transmit no torque. The configuration of the switchable coupling devices 29 as a disengageable freewheel 63 prevents jamming or blocking and also slipping of the Fahrradtretlagergetrie BES 1 when switching. Here, “shifting” or the shifting process 50 refers to the temporal transition from one shifting position 39 to another shifting position 41, i.e. the transition between two consecutive shifting positions 39, 41. Slipping of the bicycle bottom bracket gear during a shifting process 50 should be prevented if possible since in this case the crank arms can slip through when pedaling by the user and the user of the bicycle can injure himself.

In order to prevent slipping, at least one switchable clutch device 29 is always engaged during a switching process 50 on each transmission shaft 3, 5, 7, which has switchable clutch devices 29 with gear wheels 24. In the short term, two switchable clutch devices 29 on each transmission shaft 3, 5, 7 can be engaged during a switching process 50.

The switchable clutch devices 29 designed as disengageable freewheels 63 preferably each have two face-toothed toothed discs 65 and 67 . In the engaged state 31, the two face-toothed toothed discs 65 and 67 engage in one another in a force-transmitting manner. The face-toothed toothed disks 65 and 67 are designed and oriented in such a way that they mesh in one direction of rotation relative to one another in a force-transmitting manner and can slide past one another in an opposite direction of rotation. The orientations are of course selected in such a way that power can be transmitted from the input shaft 3 in the direction of the output shaft 5, ie in the power transmission direction 19.

A toothed disc 65 formed as a freewheel 63 switchable clutch device 29 is rotatably connected to the gear 27 to which this switchable clutch device 29 heard ge. In particular, the toothed disk 65 can be formed in one piece with the gear wheel 27 .

The other toothed disc 67 of this freewheel 63 is non-rotatably connected to the clutch body 61 of the switchable clutch device 29, or formed in one piece with it. In this way, the clutch body 61 can be engaged with the gear wheel 27 . The transmission shafts 3, 5 and 7, and preferably also the selector shafts 47, can be mounted in a stationary manner in a common transmission housing 69. The common housing 69 is indicated by dashed lines in FIG. Suitable bearings 71, for example ball bearings or roller bearings, can be present for storage.

An advantageous embodiment of a bicycle bottom bracket transmission 1 is described in more detail below with reference to FIGS. The structure of the bicycle bottom bracket gear 1 essentially corresponds to the bicycle bottom bracket gear 1, which was described above with reference to the schematic representation in FIG. For the sake of brevity, only the details that are not shown in FIG. 1 or have not yet been described with reference to FIG. 1 are mentioned below.

FIG. 2 shows a section through the bicycle bottom bracket gear 1, the view essentially corresponding to the view of FIG. The cutting axis runs through the axis of rotation 21, 23 and 25 of the transmission shafts 7, 3 and 5.

Fig. 3 shows an enlarged representation of the section of Fig. 2 marked with "X".

The three gears 27 on the input shaft 3, each of which can be connected in a rotationally fixed manner to the input shaft 3 by means of a switchable clutch device 29, are referred to below as 27a, 27b and 27c for better differentiation.

The three gears 27 on the output shaft 5, each of which can be connected in a torque-proof manner to the output shaft 5 by means of a switchable clutch device 29, are referred to below as 27d, 27e and 27f.

The five non-rotatable gear wheels 34 of the intermediate shaft 7 are numbered consecutively with the designations 34a to 34e in the following.

Gear 27a of input shaft 3 preferably has 76 teeth and meshes with gear 34a of intermediate shaft 7, which preferably has 22 teeth. Gear 27b preferably has 30 teeth and meshes with gear 34c of intermediate shaft 7, which preferably also has 30 teeth. Gear 27c of input shaft 3 preferably has 52 teeth and meshes with gear 34d of intermediate shaft 7, which preferably has 28 teeth.

Gear 27d of output shaft 5 preferably has 33 teeth and meshes with gear 34b of intermediate shaft 7, which preferably has 22 teeth. The gear 27e of the Input shaft 5 preferably has 28 teeth and meshes with gear 34d of intermediate shaft 7, which has 28 teeth. Gear 27f of output shaft 5 preferably has 27 teeth and meshes with gear 34e of intermediate shaft 7, which preferably has 22 teeth.

Consequently, the gear 34 d of the intermediate shaft 7 is the only gear 34 of the intermediate shaft 7 both with a gear 27 of the input shaft 3 and with a gear 27 of the output shaft 5 in engagement. Compared to an arrangement in which each gear wheel of the input shaft is connected to a gear wheel of the output shaft via a gear wheel of the intermediate shaft, the arrangement described here may increase the number of gear wheels 34 on the intermediate shaft 7, but well-defined gear gradations are thereby possible.

Gears 34b and 27d form a pair 44 meshing gears. Gears 34e and 27f form another pair 46 of meshing gears. Both pairs 44 and 46 form different gear ratios, with the gears 34b and 34e of the intermediate shaft 7 belonging to the pairs 44 and 46 having the same number of teeth, namely 22.

The developments (reciprocal values of the translations) resulting from the combinations of the gears 27 and 34 described above are briefly described below.

The following developments result from the gear wheels 27 on the input shaft 3 and the gear wheels 34 on the intermediate shaft 7:

Gear 27a meshing with gear 34a results in a deployment of 3.455. For the gear 27b in mesh with the gear 34c there is a deployment of 1. For the gear 27c in mesh with the gear 34d there is a deployment of 1.86.

The gears 34 on the intermediate shaft 7 and the gears 27 on the output shaft 5 result in the following deployments: gear 34b meshing with gear 27d results in a deployment of 0.667. Gear 34d in mesh with gear 27e gives a deployment of 1. Gear 34e in mesh with gear 27f gives a deployment of 0.815.

Overall, this results in the following nine gears 43 for the bicycle bottom bracket gear 1:

Gear 27b of input shaft 3 meshes with gear 34c of intermediate shaft 7 in gears 1 to 3. Here, in gear 1, the gear 27d of the output shaft meshes with the gear 34b of the intermediate shaft 7 and the total deployment is 0.667. In progress 2 the gear 27f of the output shaft 5 meshes with the gear 34e of the intermediate shaft 7 and the total deployment is 0.815. In gear 3, gear 27e of output shaft 5 meshes with gear 34d of intermediate shaft 7 and total deployment is 1.

Gear 27c of input shaft 3 meshes with gear 34d of intermediate shaft 7 in gears 4 to 6. Here, in gear 4, the gear 27d of the output shaft 5 meshes with the gear 34b of the intermediate shaft 7 and the total deployment is 1.238. In gear 5, gear 27f of output shaft 5 meshes with gear 34e of intermediate shaft 7 and the total deployment is 1.513. In gear 6, gear 27e of output shaft 5 meshes with gear 34d of intermediate shaft 7 and the total deployment is 1.857. Gear 27a of input shaft 3 meshes with gear 34a of intermediate shaft 7 in gears 7 through 9. Here, in gear 7, the gear 27d of the output shaft 5 meshes with the gear 34b of the intermediate shaft 7 and the total deployment is 2.303. In gear 8, gear 27e of output shaft 5 meshes with gear 34d of intermediate shaft 7 and the total deployment is 2.815. In gear 9, gear 27f of output shaft 5 meshes with gear 34e of intermediate shaft 7 and the total deployment is 3.455.

The respective possible gears are indicated in FIG. 2 for each gear wheel 27 in small boxes. It applies here that for each of the 9 gears a gear wheel 27 on the input shaft 3 and a gear wheel 27 on the output shaft 5 must be non-rotatably connected to the respective transmission shaft. The information on the gears used in FIG. 2 can be read in such a way that both gears assigned to a desired gear must be non-rotatably connected to their transmission shaft. For example, for the third gear, the gear wheel 27b of the input shaft 3 and the gear wheel 27e of the output shaft 5 must be non-rotatably connected to its transmission shaft. The respective other gears 27 must rotate freely on the respective transmission shaft. The gears 43 mentioned above result in a bandwidth of 518% for the bicycle pedal bearing gear 1. Such a bandwidth can cover most areas of use for bicycles. The gear steps are between 22.2% and 24%, which can significantly increase driving comfort.

An advantageous embodiment of a switchable clutch device 29 is briefly discussed below with reference to FIG. 3 . All switchable coupling devices 29 are preferably of the same structure, so that a switchable coupling device 29 is described in general terms at this point. The switchable clutch device 29 in Fig. 3 is merely an example shown and described arranged on the input shaft 3. The description applies analogously to the switchable clutch devices 29 on the output shaft 5.

The coupling device 29 serves to connect the gear wheel 27, which is freely rotatably mounted on the input shaft 3, to the input shaft 3 in a rotationally fixed manner. The switchable clutch device 29 has a clutch body 61 . The coupling body 61 extends be preferably completely once around the input shaft 3 around. Only a section of the coupling body 61 is shown in FIG. 3 .

The clutch body 61 is held in the axial direction, ie parallel to the axis 23 of the input shaft 3 so as to be displaceable on the latter. In contrast to the gear wheel 27, however, the clutch body 61 is connected to the input shaft 3 in a rotationally fixed manner. For this purpose, the surface of the input shaft 3 has teeth 73 at least in the area in which the clutch body 61 is to be able to be moved. The toothing 73 can be formed according to DIN 5480 in particular. However, this is not mandatory. Other toothings are also possible. The clutch body 61 is provided with teeth 75 complementary to the teeth 73 so that it can be displaced along the axis 23 but not freely rotated about the input shaft 3 .

The coupling body 61 has a toothed disc 67 which has face teeth. The toothed disk 67 is preferably formed in one piece with the rest of the clutch body 61 . The gear wheel 27 also has a toothed disc 65 with face gearing. The face-toothed toothed disk 65 of the gear wheel 27 is preferably formed in one piece with the gear wheel 27 .

The face-toothed toothed disks 65 and 67 are preferably formed complementary to one another and are shaped in such a way that together they form the freewheel 63 that can be disengaged. This has already been described above with reference to FIG. 1 . Preferably, the toothed discs 65 and 67 each have a sawtooth-shaped toothing.

When the two face-toothed toothed disks 65 and 67 mesh with one another, the gear wheel 27 is connected to the input shaft 3 in a torque-proof manner, at least in such a way that power can be transmitted from the input shaft 3 to the gear wheel 27 in order to transmit power along the power transmission direction 19 from of the input shaft 3 to the output shaft 5. In contrast, the gearwheel 27 can rotate freely in the opposite direction due to the freewheel 63 .

If the two face-toothed toothed discs 65 and 67 are separated from one another, the gear wheel 27 on the input shaft 3 rotates freely. The freely rotating state is shown in FIG. Of the freely rotating state corresponds to the disengaged state 33 of the switchable Kupplungsvor direction 29.

The switchable clutch device 29 has a pressing device 77 which is functionally coupled to the clutch body 61 . The pressing device 77 is designed to press the hitch be body 61 against the gear 27 as long as the switching yoke 55 does not exert any opposite release force F _A on the clutch body 61 . Without the action of force from the switching yoke 55, the clutch body 61 is therefore in engagement with the gear wheel 27.

In the configuration shown here as an example, the switching yoke 55 does not act directly on the clutch body 61 but only indirectly via a release body 56 . As shown, the release body 56 can be a ring, which is preferably wear-resistant, for example hardened. The release body 56 can rotate with the transmission shaft and thus relative to the shift yoke 55. Alternatively, the release body can also be stationary relative to the switching yoke 55, as explained below.

The pressing device 77 preferably has a plurality of spring elements 79 which are arranged between the clutch body 61 and an abutment 81 arranged on the input shaft 3 . The spring elements 79 are preferably compression springs 82 which are inserted compressed between the abutment 81 and the clutch body 61 and permanently exert a force on the clutch body 61 which presses it in the direction of the gear wheel 27 .

The abutment 81 can be a ring arranged on the input shaft 3 , for example a retaining ring, which is held in a groove 84 in the input shaft 3 in such a way that it cannot be displaced along the axis 23 .

The coupling body 61 can be provided with receptacles 83 for the spring elements 79 . Each switchable clutch device preferably has a plurality of spring elements 79 which are arranged at different positions along a circumferential direction 85 around the input shaft 3 at a distance from one another. The spring elements 79 are preferably arranged equidistant from one another.

If there is an even number of spring elements 79, these are preferably arranged diametrically opposite one another across the axis 23. Due to the plurality of spring elements 79, a uniform pressure on the clutch body 61 in the direction of the gear 27 can be generated. In order to move the clutch body 61 away from the gear TI, the clutch body 61 is functionally coupled to the release body 56 . A part of this can ring around the body 61 run around the clutch. This is shown in cross section in FIG. Since in the illustrated embodiment the switching yoke 55 and the release body 56 do not rotate with the input shaft 3, but the clutch body 61 is connected to the input shaft 3 in a rotationally fixed manner, a bearing 87, in particular a ball bearing 87, is located between the release body 56 and the clutch body 61 The clutch body 61, or additionally or alternatively the release body 56, can be provided with a raceway 89 for the ball bearing 87.

As an alternative to this, a ball bearing cage can also be arranged between the release body 56 and the clutch body 61 and can transmit a force between the release body 56 and the clutch body 61 .

In order not to lose the release body 56 during assembly, a ring element 91 can be provided, for example in the form of a spacer ring, with the release body 56 being arranged along the axis 23 between the ball bearing 87 and the ring element 91 . The ring element 91 can in particular be made of plastic. The coupling body 61 can also have a further locking ring 92 which in turn secures the ring element 91 against sliding along the axis 23 .

The actuation of the switchable clutch devices 29 with the aid of the switching yokes 55 and the release body 56 is briefly described below with reference to FIG. 4 . 4 shows a switchable clutch device 29 in the engaged state 31 and a switchable clutch device 29 in the disengaged state 33. FIG of the switching yokes 55, 55' are switched.

A drive torque M _EIP is, for example, introduced into the input shaft 3 and passed on to a small gear wheel 27a or a large gear wheel 27b via two switchable clutch devices 29 . The small gear 27A is connected to a large gear 34a of the intermediate shaft 7. The large gear 27b is connected to a small gear 34b of the intermediate shaft 7. The output torque M _OUT is transmitted from the intermediate shaft 7 to other areas of the bicycle bottom bracket gear 1. In the illustration, the intermediate shaft 7 rotates at a higher speed than the input shaft 3 because the gears 27b and 34b transmit power. In the engaged state 31, which is shown at the bottom in FIG. 4, the clutch body 61 is pressed against the gear wheel 27 by the pressing device 77 and is engaged with it. As a result, the gear 27 is non-rotatably connected to the transmission shaft, which is identified here as an input shaft 3, merely by way of example. The switching yoke 55 does not exert any force on the clutch body 61 . The switching yoke 55 is preferably detached from the clutch body 61 in this case. This can be achieved in that the release body 56 is accommodated in the clutch body 61 with play 93 relative to the switching yoke 55 .

In the disengaged state 33, the clutch body 61 has been pushed so far out by the switching yoke 55 that the face-toothed toothed disks 67 and 65 no longer mesh. The spring elements 79 are compressed in this state.

The switching yoke 55 ^' presses against the release body 56 and keeps the clutch open.

As soon as the switching yoke 55 releases the clutch body 61 again, the spring elements 79 can press the clutch body 61 against the gear wheel 27 again, so that the engaged state 31 is assumed.

Each switching yoke 55 is movably mounted on the switching shaft 47 . In order to prevent the shifting yoke 55 from tilting, each shifting yoke 55 is held displaceably on the shifting shaft 47 at two bearing points 95 and 97 which are spaced apart axially.

Each switching yoke 55 is provided with a switching cam 57 . The switching cam 57 acts together men with a shift gate 59 which is rotatably connected to the shift shaft 47.

Each shifting gate preferably has exactly one raised position 99, which shifts the shifting cam 57 in such a way that the shifting yoke 55 shifts the clutch body 61 against the spring force of the pressing device 77 into the disengaged state 33.

The raised positions 99 of the shifting gates 59 on a shifting shaft 47 are offset in such a way that in each shifting position there is exactly one shiftable clutch device 29 in the engaged state 31 and all other shiftable clutch devices 29 of the same transmission shaft in the disengaged state 33. The switchable Kupplungsvor devices 29 of a transmission shaft are thus coupled to one another by the associated switching device 35 or 37 .

The rotary movement 45 of the selector shaft 47 also rotates the shifting gates 59 and shifts the shifting cams 57 accordingly. The following describes how slipping of the bicycle bottom bracket gear 1 can be avoided during a shifting process.

Slipping occurs when, in Fig. 4, toothed discs 65 and 67, for example, with face teeth, in the shiftable clutch device 29 and toothed discs 65' and 67', for example, with face teeth, in the switchable clutch device 29' are not exerting any forces at the same time at a point in time during the shifting process 50 the respective gears 27a and 27b can transmit, so for example both are in a decoupled state 33 at the same time.

The face-toothed toothed disk 67 ′ is displaced axially in the direction of the axis 23 . The coordinate _Xa in FIG. 4 represents this axial movement of the shifting yoke 55 ^' . The coordinate _Xb in FIG. 4 represents the analogous axial movement of the shifting yoke 55. The coordinate Xa is the distance from _a reference surface of the shifting gate 59 ^' to a reference point on the switching yoke 55 ^' . The coordinate X _b is the distance from a reference surface of the shifting gate 59 to a reference point on the shifting yoke 55. If the coordinates X _a and the coordinates X _b are plotted as a function of the angle of rotation a of the shifting shaft 47, the result shown in Fig 5 shown switching logic for the two-speed gearbox of Fig. 4.

It can be seen in FIG. 5 that the two switching positions 39 and 41 are reached at a rotation angle a of 90° and at a rotation angle of 240°. In Fig. 4 only the switching position 41 is shown. FIG. 5 thus shows schematically the course of the axial heights of the two shifting gates 59 and 59 ^' of FIG. 4 over the angle of rotation a of the shifting shaft 47.

At a rotation angle a of 240°, the shifting gate 59 ^' has shifted the shifting yoke 55 ^' axially along the axis 51 to such an extent that the shiftable clutch device 29 ^' has separated the positive connection of the gear wheel 27a with the input shaft 3. At a rotation angle of 240°, the shifting gate 59 has shifted the shifting yoke 55 axially along the axis 51 to such an extent that the shiftable clutch device 29 has closed the positive connection of the gear wheel 27b with respect to the input shaft 3 .

It makes sense for a switching position 39, 41 not only to be set exactly at an exact value of the angle of rotation a, for example at an angle of rotation a of exactly 240°, but also in a tolerance range that extends over several degrees, for example about 10° or 20 ° extends. So For example, the tolerance range can extend from 235° to 245°. In this way, the shift gates 59 do not have to be manufactured with such precision, which saves costs.

At a rotation angle a of 90°, the shifting gate 59 ^' has shifted the shifting yoke 55 ^' axially along the axis 51 until the shiftable clutch device 29 ^' is engaged and the gear wheel 27a is positively connected to the input shaft 3.

Analogously, the shift gate 59 has shifted the shift yoke 55 axially along the axis 51 at the angle of rotation a of 90° to such an extent that the shiftable clutch device 29 is disengaged and the positive connection of the gear wheel 27b with respect to the input shaft 3 is separated. This separation is accomplished by the teeth of the face-toothed toothed discs 65 and 67 passing through the range of 50 to 85 degrees, for example, during the rotary movement of the selector shaft.

In the disengaged state 33, the switching cam 57 is in a raised position 99 on the shift gate 59. In the fully engaged state 31, the face-toothed toothed discs 65 and 67 touch with or without relative movement on the toothed side to such an extent that they generate a torque in one direction of rotation can transfer.

The face-toothed pulleys 65 and 67 can take three modes. In a first mode of operation, the face-toothed toothed discs 65 and 67 do not touch on the toothed side in the disengaged state 33 . In the second, the face-toothed toothed discs 65 and 67 touch on the toothed side and slide off one another with a relative movement. The second operating state occurs in the transition from the disengaged to the engaged state.

A third mode of operation is achieved when, in the fully engaged state 31, the planar toothed pulleys 65 and 67 mesh positively on the toothed side, have no relative movement to one another and transmit torque in one direction of rotation. The second mode of operation occurs exclusively during the shifting process 50 on. The second mode does not occur when the bicycle is being ridden in a particular shift position 39 or 41.

Slipping can therefore be prevented if a switchable clutch device 29 is only switched from the engaged state 31 to the disengaged state 33 if at least one other switchable clutch device 29 on the same transmission shaft is in the engaged state 31 during this shifting process. Since the face-toothed toothed disks 65 and 67 are held in the engaged state 31 exclusively by a spring element 79, the transmission cannot become blocked during the shifting process 50 if two or more shiftable clutch devices 29 are in the engaged state 31 during the shifting process 50 . During this switching process 50, two or more switchable clutch devices 29 can be in the engaged state 31, but only one switchable clutch device 29 can transmit the forces to a transmission shaft 3, 5 in this configuration. The other switchable coupling device 29 runs freely.

FIG. 6 shows a schematic representation of two selector shafts 47 such as are shown in FIG. 1, for example. Depending on its angle of rotation a, each selector shaft 47 switches three switch positions 39, 41, 101 on the gear shaft 3, 5 assigned to it (cf. FIG. 1). The three switching positions 39, 41, 101 are preferably separated from each other by the same angle of rotation α. For example, each switch position 39, 41, 101 is separated from the adjacent switch position by a rotation angle α of 120°. As described in connection with FIG. 5, each switching position can extend over a rotational angle range, for example ±10° or ±20° from a central position. The angle of rotation range over which a shift position extends is hatched in FIG. 6 for the respective shift shaft.

In this embodiment, starting from any switching position 39, 41, 101, any other switching position 39, 41, 101 of a switching device can be reached by just a single switching movement 38. Since each different combination of switching positions 39, 41, 101 of the two gear shafts 47 represents a different gear of the 9 gears of this bicycle radtretlagertriebs, each gear can be achieved in this way by performing only one switching movement 38 on each gear shaft 47. For example, it is possible to switch from the combination 39, 41 of the switching positions to the combination 41, 101 or any other combination by only one switching movement 38 in each case. If the two switching movements 38 take place at the same time, it is possible to switch from one gear to any other gear very quickly.

In modifications of the embodiment shown in Fig. 6, a selector shaft 47 can also only have two switch positions 39, 41, resulting in a 6-speed bicycle bottom bracket gearbox 1, or in a 4-speed bicycle bottom bracket gearbox both switch shafts can also only have two switch positions 39, 41 exhibit. Reference sign

1 bicycle bottom bracket gear

3 input shaft

5 output shaft

7 intermediate shaft

9 pedal crank set

11 engine

13.15 gear

17 drive pinion

19 power transmission direction

21, 23, 25 axis of rotation 27, 27a-f, 27A, 27B gear wheels 29, 29' switchable clutch device

31 engaged state

33 disengaged state

34, 34a-e gears

35, 37 switching devices 38 switching movement

39, 41 switching positions

42 power flow

43 speed

44 pairs of meshing gears

45 rotary movement

46 pairs of meshing gears

47 shift shaft

49 actuator

50 switching process

51 Axis of the selector shaft 53 Shift subassembly

55, 55' switching yoke

56 clutch body end of the switching yoke

57 switching cam

59, 59' shift gate

61 clutch body 63 freewheel

65, 67, 65', 67' toothed pulleys with face teeth

69 gear case

71 camp

73, 75 serration

77 pressing device

79 spring element

81 abutment

82 compression spring

83 recording

84 slots

85 circumferential direction 87 bearing 89 raceway

91 ring element

92 locking ring

93 game

95, 97 bearing points 99 higher position 101 switching position FA release force MEIP input torque MAUS output torque

Release movement a rotation angle

Claims

Expectations

1. Bicycle bottom bracket gear (1), with at least one gear shaft (3, 5, 7), on which gears (27, 34) coupled with a switchable clutch device (29) are arranged, the clutch devices (29) between an engaged state (31) and a disengaged state (33), wherein in the engaged state a clutch device (29) connects the gear wheel (27, 34) coupled to it in at least one direction of rotation of the respective transmission shaft (3, 5, 7) with the respective Transmission shaft (3, 5, 7) rotates and when the clutch device (29) is in the disengaged state, the gear wheel (27, 34) can rotate freely relative to the respective transmission shaft (3, 5, 7), with at least one switching device (35, 37) for switching the clutch devices of a transmission shaft (3, 5, 7), each transmission shaft (3, 5, 7) on which gear wheels (27, 34) coupled with a switchable clutch device (29) are arranged, a other switching device (35, 37) is assigned, each switching device (35, 37) having at least two switching positions (39, 41) and by means of a switching movement from one of the switching positions (39, 41) to another of the switching positions (39, 41) is designed to be transferrable, with each of the switching positions (39, 41) of a switching device (35, 37) representing a different combination of the engaged and disengaged states (31, 33) of the clutch devices (29) of the transmission shaft (3, 5, 7 ) corresponds, wherein during each switching movement (38, 45) at least one of the clutch devices (29) which is arranged on the transmission shaft (3, 5, 7) assigned to a switching device (35, 37) is engaged, and wherein the at least a gear shaft (3, 5, 7) at least one gear shaft (3, 5, 7) from the group containing an input shaft (3) of the bicycle bottom bracket gearbox (1), an output shaft (5) of the bicycle bottom bracket gearbox (5) and little at least one intermediate shaft (7) of the bicycle bottom bracket gear (1).

2. Bicycle bottom bracket transmission (1) according to claim 1, wherein, starting from one of the switching positions (39, 41) of a switching device (35, 37), each other of the switching positions (39, 41) of this switching device (35, 37) by exactly one Switching movement (38, 45) can be reached.

3. Bicycle bottom bracket transmission (1) according to claim 1 or 2, with at least two transmission shafts (3, 5, 7) on which gear wheels (27, 34) each coupled with a coupling device are arranged, and with at least two switching devices (35, 37 ) for switching the Kupplungsvor directions (29) in each case one of the at least two transmission shafts (3, 5, 7).

4. Bicycle bottom bracket transmission (1) according to claim 3, wherein the switching positions (39, 41, 101) of one of the at least two switching devices (35, 37) are independent of the switching positions (39, 41, 101) of another of the at least two switching devices (35, 37) are ingestible.

5. Bicycle bottom bracket gear (1) according to claim 3 or 4, wherein the shifting movements (38, 45) of one of the at least two shifting devices (35, 37) are synchronized with the shifting movements of at least one other of the at least two shifting devices (35, 37).

6. Fahrradtretlagertrieb (1) according to any one of claims 1 to 5, wherein two transmission shafts (3, 5, 7) are provided, on which each having a switchable clutch device (29) coupled gears (27, 34) are arranged, wherein the one of the two gear shafts (3, 5, 7) is an input shaft (3) of the bicycle bottom bracket gearbox (1) and the other of the two gear shafts (3, 5, 7) is an output shaft (5) of the bicycle bottom bracket gearbox (1) and between the two Gear shafts (3, 5) an intermediate shaft (7) with gears (27, 34) is arranged and the gears (27, 34) each with a gear (27, 34) of the input shaft (3) and / or with a Gear (27, 34) of the output shaft (5) are engaged.

7. Fahrradtretlagertrieb (1) according to any one of claims 1 to 6, wherein each switching device (35, 37) has an actuator (49) for generating the switching movement (38, 45).

8. Fahrradtretlagertrieb (1) according to any one of claims 1 to 7, wherein the switching movement (38, 45) is a rotary movement (45) and all switching positions (39, 41, 101) of a Schaltvor direction (35, 37) within a full revolution are arranged.

9. Fahrradtretlagertrieb (1) according to claim 8, wherein a switching position (39, 41, 101) extends over a range of rotational movement, wherein the range is greater than 10 ° and less than 90 ° al.

10. Bicycle bottom bracket gear (1) according to one of claims 1 to 9, wherein each shifting device (35, 37) has a rotatable shifting shaft (47) and is designed, with a rotary movement (45) of the shifting shaft (47) about its axis (51) one after the other to switch over a different clutch device (29) on the transmission shaft (3, 5, 7) assigned to this switching device (35, 37).

11. Bicycle bottom bracket transmission (1) according to claim 10, wherein each shifting device (35, 37) for each of the coupling devices (29) of the shifting device (35, 37) assigned to the gear bewelle (3, 5, 7) on the shifting shaft (47) comprises an axially displaceable shift yoke (55) which is connected to a clutch body (61) of the respective clutch device (29) in a manner that transmits shift movements.

12. Fahrradtretlagertrieb (1) according to claim 11, wherein at least one yoke (55) with we least one switching cam (57) and the shift shaft (47) with at least one shift gate (59) for the switching cam (57) is provided.

13. Bicycle bottom bracket transmission (1) according to claim 12, wherein the shifting yoke (55) is held displaceably at two axially spaced bearing points (95, 97) on the shifting shaft (47) and wherein the shifting gate (59) and the shifting cam (57) between the two camps (95, 97) are arranged.

14. The bicycle bottom bracket transmission (1) according to any one of claims 1 to 13, wherein at least one of the coupling devices (29) has a pressing device (77) and a coupling body (61) coupled to the pressing device (77), the pressing device (77) being is designed to move the clutch body (61) into engagement with the gear wheel (27, 34) belonging to this clutch device (29), the pressing device (77) being arranged at least one axially immovably on the transmission shaft (3, 5, 7). Abutment (81) and at least one spring element (79) arranged between the abutment (81) and the coupling body (61).

15. Fahrradtretlagertrieb (1) according to claim 14, wherein the pressing device (77) has a plurality of spring elements (79) in a circumferential direction (85) of the gear shaft (3, 5, 7) spaced apart between the at least one abutment (81) and the coupling body (61) are arranged.

16. Fahrradtretlagertrieb (1) according to any one of claims 1 to 15, wherein at least one coupling device (29) is designed as a freewheel (63).

17. Bicycle bottom bracket transmission (1) according to claim 16, wherein the switchable clutch device (29) designed as a disengageable freewheel (63) has two face-toothed toothed discs (95, 67).

18. Fahrradtretlagertrieb (1) according to claim 17, wherein the toothed discs (95, 67) in the coupled state (33) separated from each other and in the coupled state (33) are pressed together by Fe derkraft.

19. Bicycle pedal bearing gear (1) according to one of claims 1 to 18, wherein the bicycle pedal bearing gear (1) has at least one intermediate shaft (7) arranged between an input shaft (3) and an output shaft (5) and the intermediate shaft (7) has more gears ( 34) as the input shaft (3) and/or the output shaft (5).

20. Fahrradtretlagertrieb (1) according to any one of claims 1 to 19, wherein two of the transmission shafts (3, 5, 7) together have at least two pairs (44, 46) of meshing gears (27, 34), wherein the at least two Pairs (44, 46) form different translations and at least two of the pairs (44, 46) belonging to gears (27, 34) of a transmission shaft (3, 5, 7) have the same number of teeth.

21. Bicycle bottom bracket gear (1) according to any one of claims 1 to 20, wherein each gear (27, 34) of one and the same gear shaft (3, 5, 7) that engages with the gear (27, 34) of another gear shaft (3rd , 5, 7) of the bicycle bottom bracket gear (1) is engaged, has a hitch be device (29).

22. Bicycle pedal bearing gear (1) according to one of claims 1 to 21, wherein the bicycle pedal bearing gear (1) has a plurality of gear shafts (3, 5, 7) and a plurality of switching shafts (47), the axes of rotation of which span different levels in pairs, which are not parallel to each other.