DE102021109204A1 - Bicycle bottom bracket gear with coupled coupling devices - Google Patents

Abstract

Bicycle bottom bracket gear (1) with at least one gear shaft (3, 5, 7) on which gear wheels (27, 34) coupled to a switchable clutch device (29) are arranged. The clutch devices can be switched between an engaged state (31) and a disengaged state (33). In the engaged state, a coupling device connects the gear wheel coupled to it in at least one direction of rotation of the respective gear shaft to the respective gear shaft (3, 5, 7) in a rotationally fixed manner. At least one switching device (35, 37) is provided for switching the clutch devices of a transmission shaft. In this case, each transmission shaft, on which gear wheels are arranged which are coupled to a respective shiftable clutch device, is assigned a different shifting device. Each switching device has at least two switching positions (39, 41, 101) and can be transferred from one of the switching positions to another of the switching positions by means of a switching movement (38, 45). Each of the switching positions of a switching device corresponds to a different combination of the engaged and disengaged states of the clutch devices of the transmission shaft associated with it. Starting from one of the switching positions of a switching device, each of the other switching positions of this switching device can be reached by exactly one switching movement.

Description

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 maintenance-intensive.

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. Not only when carrying, but also when cornering or when driving off-road in a sporty way, the heavy weight on the rear wheel hub is annoying.

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 gears 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, for example, from DE 10 2004 045 364 B4 known.

In conventional bicycle bottom bracket gears, increased noise development and/or a gear change that does not take place smoothly can be perceived as disadvantageous compared to other types of shifting. In addition, some bicycle bottom bracket gears cannot be shifted under load or can only be shifted with difficulty. There is consequently a need for compact and easy-to-shift bicycle bottom bracket gears that 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 transmission, with at least one transmission 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 holding the gear wheel coupled to it in the engaged state in at least one direction of rotation of the respective transmission shaft with the respective transmission shaft in a rotationally fixed manner and in the disengaged state of the clutch device the gear wheel can be freely rotated relative to the respective transmission shaft, with at least one shifting device for shifting the clutch devices of a transmission shaft, with each transmission shaft on which with one shiftable Coupling device coupled gears are arranged, another switching device is assigned, each switching device having at least two switching positions u nd is designed such that it can be transferred from one of the switching positions to another of the switching positions by means of a switching movement, each of the switching positions of a switching device corresponding to a different combination of the engaged and disengaged states of the clutch devices of the transmission shaft assigned to it, wherein, 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, and wherein the at least one gear shaft is at least one gear shaft from the group containing an input shaft of the bicycle bottom bracket gearbox, an output shaft of the bicycle bottom bracket gearbox and at least one intermediate shaft of the bicycle bottom bracket gearbox.

By coupling at least two shiftable clutch devices of a transmission shaft by the associated shifting device, it is possible to switch in a well-defined manner between the gears that are non-rotatably connected to the transmission shaft. 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. Fast gear changes are possible because, starting from any shift position, any other shift position can be reached with just one rotary movement.

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, at least one of the clutch devices, which are arranged on the transmission shaft assigned to a shifting device, can be engaged during each shifting movement.

According to a further refinement, the input shaft can be configured so that it can be connected directly or indirectly to a set of pedal cranks. The input shaft can, for example, run coaxially to 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 bracket with a reduction gear.

The output shaft can be configured so that it can be connected directly or indirectly to a drive pinion. The drive sprocket can be a chainring, a set of chainrings, 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 shift 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 wheel is preferably always engaged when shifting the gear wheels of a transmission shaft and the other gear wheels of this transmission shaft are simultaneously disengaged or left in the disengaged state. This can be done by coupling the shiftable clutch devices via the shifting 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 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 bicycle bottom bracket gear, preferably has a clutch device. In this embodiment, the coupling devices are only arranged on one of two shafts and only one switching device is required, which simplifies the construction of the bicycle pedal bearing transmission.

At least two gear wheels can be arranged on the input shaft, the output shaft and the at least one intermediate shaft, each gear wheel meshing with at least one of the gear wheels of another transmission shaft.

A particularly advantageous embodiment of the bicycle bottom bracket transmission can be obtained when the shifting movement is a rotary motion, with each gear of the bicycle bottom bracket transmission being accessible 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. This allows a faster gear change to take place. The two switching devices are particularly preferably designed to switch simultaneously.

As described above, the switching devices can preferably be actuated independently of one another. In particular, if these are actuated simultaneously and/or the shifting movements of different shifting devices are synchronized, a gear change can take place 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, one after the other, at least from the to switch 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. All switching positions of this switching device can preferably 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 to transmit switching movements. The shift yoke can preferably interact with the clutch body at two diametrically opposite sills of the clutch body via the transmission shaft, 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 it can in turn move the clutch body, the shifting yoke is preferably provided with at least one shifting cam and the shifting shaft is provided 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 flat 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 pressure device and a clutch body that is functionally coupled to the pressure device, the pressure device being designed to move the clutch body into engagement with the gear wheel belonging to this clutch device, the pressure device having at least one axially immovable element on the transmission shaft arranged Has 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 configuration makes it possible for the shiftable clutch device to preferentially assume the engaged state if it is released for this by the shifting device, for example because the shifting 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 wheel, the pressing device preferably has a plurality of spring elements which are arranged spaced apart from one another in a circumferential direction of the transmission shaft between the at 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 in engagement 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 set of pedal cranks, 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 disks 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 clutch 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 an unintentional disengagement of the engagement of the two toothed discs with one another, one end of the switching yoke on the clutch body side 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 gear wheels as the input and/or the output shaft.

The input and output shafts preferably have the same number of shiftable gears.

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 between the individual shafts can be achieved. 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 gear shaft via switchable clutch devices, at least the gears that are constantly engaged with a gear of another gear shaft. As already described above, the input shaft and the output shaft preferably each have three such gear wheels.

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

If an electric motor is provided for support, this is preferably connected to the input shaft in a force-transmitting manner. Alternatively, the electric motor can be connected to one of the other transmission shafts.

According to a further advantageous embodiment, two of the transmission shafts together have at least two pairs of gears meshing with one another, 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, with a plurality of transmission shafts and a plurality of shifting shafts in the bicycle bottom bracket gear, the axes of rotation of these transmission shafts and shifting shafts span different planes in pairs that do not run parallel to one another. 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 have 30, 28 and 22 teeth respectively. 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 feature combinations shown as examples in the embodiments can be supplemented by further features in accordance with the above statements corresponding to the properties of the bicycle pedal bearing transmission according to the invention that are necessary for a specific application. Also, also in accordance with the above statements, individual features can be omitted from the described embodiments if the effect of this feature is not important in a specific application.

The Fahrradtretlagertrieb in one of the above, generally described embodiments or according to an embodiment described below, instead of the gearbox of the bottom bracket circuit DE 10 2021 101 415.8 , to which reference is hereby made in full.

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.

• 1 eine schematische Darstellung eines erfindungsgemäßen Fahrradtretlagergetriebes;
• 2 eine schematische Schnittdarstellung durch eine beispielhafte Ausführungsform eines erfindungsgemäßen Fahrradtretlagergetriebes;
• 3 ein Detail des Fahrradtretlagergetriebes aus 2; und
• 4 eine schematische Schnittdarstellung durch eine beispielhafte Ausführungsform eines Teils einer Schaltvorrichtung für ein erfindungsgemäßes Fahrradtretlagergetriebe;
• 5 eine schematische Darstellung einer beispielhaften zeitlichen Bewegungsabfolge von zwei Kupplungen während eines Schaltvorgangs;
• 6 eine schematische Darstellung der Schaltbewegungen eines Fahrradtretlagergetriebes.

Show it:

• 1 a schematic representation of a bicycle pedal bearing transmission according to the invention;
• 2 a schematic sectional view through an exemplary embodiment of a bicycle pedal bearing transmission according to the invention;
• 3 a detail of the bicycle bottom bracket gear 2 ; and
• 4 a schematic sectional view through an exemplary embodiment of part of a switching device for a bicycle pedal bearing transmission according to the invention;
• 5 a schematic representation of an exemplary temporal sequence of movements of two clutches during a shift;
• 6 a schematic representation of the switching movements of a bicycle bottom bracket gear.

In the following, the principle of the bicycle pedal bearing gear according to the invention is based on the schematic sketch 1 explained.

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 set of pedal cranks 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 1 a set of pedal cranks 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 to the rear wheel (not shown) in a power-transmitting manner. For this purpose, the output shaft 5 can have a gear wheel 15, which can be used as a drive pinion for a chain or a belt. As an alternative to this, the gear wheel 15 can also be or can be connected directly or indirectly in a force-transmitting manner to a drive pinion 17 . this is in 1 indicated by dashed lines.

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 perpendicular to their axes of rotation 21, 23 and 25. However, this is not mandatory. In the schematic representation according to 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 embodiment, 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 plane. An even more compact design results when the axes of rotation 51' and 25 span a third level and the axes of rotation 51" and 23 span a fourth level, with the first, second, third and fourth levels not being identical To build up utilization 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 which can be connected in a torque-proof manner to their respective transmission shaft 3 or 5 by means of a switchable clutch device 29 .

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

The gearwheels 27 are freely rotatably mounted on their respective transmission shaft 3 or 5, provided that they are not connected in a rotationally fixed manner to their transmission shaft 3 or 5 by their respective switchable clutch device 29 . The gears 27 can be mounted on the transmission shaft 3 or 5, in particular by means of slide or roller bearings.

In 1 the gear wheel 27 shown on the right of the input shaft 3 and the gear wheel 27 shown on the right on the output shaft 5 are shown in the engaged state 31 . These gears 27 are thus connected to their respective transmission shaft 3 or 5 in a rotationally fixed manner by their switchable clutch devices 29 .

The other two gears 27 on the input shaft 3 and on the output shaft 5 are shown in the disengaged state 33 by their switchable clutch device 29 on the transmission shaft 3 or 5 are loosened so that they can rotate freely.

The intermediate shaft 7 has a total of 5 gears 34, all of which are connected to the intermediate shaft 7 in a torque-proof 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 each mesh with only one gear 27 of the input shaft 3, two gears 34 of the intermediate shaft 7 each mesh with only one gear 27 of the output shaft 5 and one gear 34 of the intermediate shaft 7 meshes with a gear 27 of the input shaft 3 and with a gear 27 of the output shaft 5 in engagement.

To control the switchable clutch devices 29, each transmission shaft, which is provided with gears 27 that can be connected in a rotationally fixed manner 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 in 1 Schematically illustrated bicycle bottom bracket gear 1 are thus assigned to the input shaft 3 a switching device 35 and the output shaft 5 is a switching device 37 .

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

The switching device 35 assigned to 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 to 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 , with exactly one of the switchable clutch devices 29 being in the engaged state 31 in each switch position 39 and the two other switchable clutch devices 29 being in the disengaged state 33 . This is achieved in that all three shiftable clutch devices 29 of the input shaft 3 are coupled to one another by the shifting 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. Consequently, in each switching position 39, the input shaft 3 is connected in a force-transmitting manner to the intermediate shaft 7 via precisely one of its gearwheels 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 to the intermediate shaft 7 in a force-transmitting manner via exactly one of its gearwheels 27. This is also achieved here in that all three shiftable clutch devices 29 of the output shaft 5 are coupled to one another by the shifting device 37 .

Since exactly one gear 27 of the input shaft 3 is always non-rotatably connected to the input shaft 3 and exactly one gear 27 of the output shaft 5 is non-rotatably connected to the output shaft 5, and all gears 27 of the input shaft 3 and all gears 27 of the input shaft 5 are each connected to a gear 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 1 , in which a gear wheel 27 is shown on both the input shaft 3 and the output shaft 5 in a rotationally fixed manner connected to 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 in 1 indicated by a dashed line.

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 switchable coupling devices 29, the bicycle bottom bracket transmission 1 shown as an example has a total of nine gears.

The configuration of the individual gears in an advantageous embodiment of a bicycle bottom bracket gear 1 are described below with reference to FIG 2 explained.

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 bicycle bottom bracket gear 1 can be reached within a full revolution of each of the two switching devices 35 and 37 . 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 configuration makes it possible, starting from any gear 43, to reach any other gear 43 within a single rotation of both shifting 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 includes a switching yoke 55, a switching cam 57 and a switching gate 59 for the switching cam 57. These are in 1 only indicated schematically and are later with reference to the 4 described in more detail.

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 the shift gate 59, which can interact with the shift cam 47, is designed to alternately rise and fall or set back and forth in the direction of the axis 51 of the shift shaft 47.

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. As an alternative to this, a switching cam 57 can be connected in a rotationally fixed manner to the switching shaft 47 and a shifting gate 59 can be connected firmly to the switching 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 shifting yoke 55 is connected to a clutch body 61 of that shiftable clutch device 27 in a shifting movement-transmitting manner to which this shifting subunit 53 is assigned. 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 every shift Position 39 or 41 in each case exactly one switching yoke 55 of this switching shaft 47 switches the associated switchable clutch device 29 into the engaged state 31 . In other words, two shiftable clutch devices 29 are switched into the disengaged state 33 by two shifting yokes 55 of this shifting 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 in any direction of rotation relative to the drive pinion 17 and no torque can be generated 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 design of the switchable clutch devices 29 as a disengageable freewheel 63 prevents jamming or blocking and also slipping of the bicycle bottom bracket gear 1 when shifting. Here, “switching” or the switching process 50 refers to the temporal transition from one switch position 39 to another switch position 41, i.e. the transition between two consecutive switch positions 39, 41.

If possible, the bicycle bottom bracket gear should be prevented from slipping during a shifting operation, since in this case the crank arms can slip when the user is pedaling 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 shifting process 50 on each transmission shaft 3, 5, 7, which has switchable clutch devices 29 with gear wheels 24. During a shifting process 50, two shiftable clutch devices 29 can also be briefly engaged on each transmission shaft 3, 5, 7.

The switchable clutch devices 29 designed as disengageable freewheels 63 each preferably have two face-toothed toothed disks 65 and 67 . In the engaged state 31, the two face-toothed toothed disks 65 and 67 mesh with 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 of a switchable clutch device 29 formed as a freewheel 63 is connected in a rotationally fixed manner to the gear wheel 27 to which this switchable clutch device 29 belongs. 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 stationarily mounted in a common transmission housing 69. The common housing 69 is in 1 indicated by dashed lines. Suitable bearings 71, for example ball bearings or roller bearings, can be present for storage.

The following is an advantageous embodiment of a bicycle bottom bracket gear 1 with reference to 2 and 3 described in more detail. The structure of the Fahrradtretlagertriebes 1 corresponds essentially to the Fahrradtretlagertrieb 1, which above with reference to the schematic representation in FIG 1 was described. For the sake of brevity, only the details that are included in the 1 are not shown, or with reference to the 1 have not yet been described.

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

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

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

The three gears 27 on the output shaft 5, which can each 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. The gear 27b preferably has 30 teeth and meshes with the gear 34c of the 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. Gear 27e of output 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 34d of the intermediate shaft 7 as the only gear 34 of the intermediate shaft 7 meshes both with a gear 27 of the input shaft 3 and with a gear 27 of the output shaft 5 . 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 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.

• Für das Zahnrad 27a in Eingriff mit dem Zahnrad 34a ergibt sich eine Entfaltung von 3,455. Für das Zahnrad 27b in Eingriff mit dem Zahnrad 34c ergibt sich eine Entfaltung von 1. Für das Zahnrad 27c in Eingriff mit dem Zahnrad 34d ergibt sich eine Entfaltung von 1,86.

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. Gear 27b in mesh with gear 34c gives a deployment of 1. Gear 27c in mesh with gear 34d gives 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.

• In den Gängen 1 bis 3 ist jeweils das Zahnrad 27b der Eingangswelle 3 mit dem Zahnrad 34c der Zwischenwelle 7 in Eingriff. Dabei ist in Gang 1 das Zahnrad 27d der Ausgangswelle mit dem Zahnrad 34b der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 0,667. In Gang 2 ist das Zahnrad 27f der Ausgangswelle 5 mit dem Zahnrad 34e der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 0,815. In Gang 3 ist das Zahnrad 27e der Ausgangswelle 5 mit dem Zahnrad 34d der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 1.
• In den Gängen 4 bis 6 ist jeweils das Zahnrad 27c der Eingangswelle 3 mit dem Zahnrad 34d der Zwischenwelle 7 in Eingriff. Dabei ist in Gang 4 das Zahnrad 27d der Ausgangswelle 5 mit dem Zahnrad 34b der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 1,238. In Gang 5 ist das Zahnrad 27f der Ausgangswelle 5 mit dem Zahnrad 34e der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 1,513. In Gang 6 ist das Zahnrad 27e der Ausgangswelle 5 mit dem Zahnrad 34d der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 1,857.
• In den Gängen 7 bis 9 ist jeweils das Zahnrad 27a der Eingangswelle 3 mit dem Zahnrad 34a der Zwischenwelle 7 in Eingriff. Dabei ist in Gang 7 das Zahnrad 27d der Ausgangswelle 5 mit dem Zahnrad 34b der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 2,303. In Gang 8 ist das Zahnrad 27e der Ausgangswelle 5 mit dem Zahnrad 34d der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 2,815. In Gang 9 ist das Zahnrad 27f der Ausgangswelle 5 mit dem Zahnrad 34e der Zwischenwelle 7 in Eingriff und die gesamte Entfaltung beträgt 3,455.

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 gear 2, gear 27f of output shaft 5 meshes with gear 34e of 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.
• In gears 7 to 9, the gear wheel 27a of the input shaft 3 is connected to the gear wheel 34a the intermediate shaft 7 engaged. 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 possible gears are in 2 indicated for each gear 27 in 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. In the 2 The information used for the gears can be read in such a way that both gears assigned to a desired gear must be connected to their transmission shaft in a rotationally fixed manner. For example, for the third gear, the gearwheel 27b of the input shaft 3 and the gearwheel 27e of the output shaft 5 must be non-rotatably connected to their transmission shaft. The respective other gears 27 must be freely rotating on the respective transmission shaft.

The gears 43 mentioned above result in a bandwidth of 518% for the bicycle bottom bracket 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.

The following is a brief description of an advantageous embodiment of a switchable clutch device 29 with reference to FIG 3 received. All switchable clutch devices 29 are preferably of the same structure, so that a switchable clutch device 29 is described in general terms at this point. The switchable clutch device 29 in is merely an example 3 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 clutch body 61 preferably extends completely once around the input shaft 3 . In 3 only a portion of the coupling body 61 is shown.

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 displaced. 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 a toothing 75 complementary to the toothing 73 so that it can be displaced along the axis 23 but cannot rotate freely 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 designed to complement one another and are shaped in such a way that together they form the disengageable freewheel 63 . This is already above with reference to the 1 described. 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 rotationally fixed 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 generate power along the power transmission direction 19 from the input shaft 3 to be transmitted to the output shaft 5. In the opposite direction, on the other hand, the gear wheel 27 can rotate freely 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 free spinning state is in 3 shown. The freely rotating state corresponds to the disengaged state 33 of the switchable clutch device 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 clutch body 61 against the gear wheel 27 as long as the switching yoke 55 does not exert any opposing release force F _A on the clutch body 61 . Without the application of force through the switching yoke 55 is the Coupling body 61 therefore meshes with 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. The release body 56 is preferably arranged between the switching yoke 55 and the clutch body 61. As illustrated, 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. A uniform pressure on the clutch body 61 in the direction of the gear wheel 27 can be generated by the plurality of spring elements 79 .

In order to move clutch body 61 away from gear 27 , clutch body 61 is operably coupled to release body 56 . A part thereof may run around the coupling body 61 in a ring shape. This is in cross section 3 shown. 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 displacement 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 with reference to FIG 4 described. the 4 shows a switchable clutch device 29 in the engaged state 31 and a switchable clutch device 29 in the disengaged state 33. The 4 shows only a portion of the bicycle bottom bracket transmission 1. The portion corresponds to a bicycle bottom bracket transmission 1 with two gears, which are shifted with the help of the shift yokes 55, 55'.

A drive torque M _Ein 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 _Aus 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 in 4 As shown below, the clutch body 61 is pressed by the pressing device 77 against the gear 27 and engaged with it. As a result, the gear wheel 27 is connected in a rotationally fixed manner to the transmission shaft, which is identified here as the input shaft 3 only by way of example. The switching yoke 55 exerts no force on the coupling 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 is so far disengaged by the switching yoke 55 that the face-toothed toothed discs 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 shifting cam 57 interacts with a shifting link 59 which is connected to the shifting shaft 47 in a rotationally fixed manner.

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 into the disengaged state 33 against the spring force of the pressing device 77 .

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 shiftable coupling devices 29 of a transmission shaft are thus coupled to one another by the associated shifting 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.

A slip occurs when in 4 the toothed discs 65 and 67, for example, with face teeth, in the shiftable clutch device 29 and the toothed discs 65' and 67', for example, with face teeth, in the shiftable clutch device 29' at a point in time during the shifting process 50 cannot simultaneously transmit any forces to the respective gear wheels 27a and 27b, i.e. to each other 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 X _a places in 4 represents this axial movement of the switching yoke 55'. The coordinate X _b represents in 4 represents the analogous axial movement of the shifting yoke 55. The coordinate X _a is the distance from a reference surface of the shifting gate 59' to a reference point on the shifting 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 entered as a function of the angle of rotation α of the shifting shaft 47, then the in 5 Shift logic shown for the two-speed manual transmission 4 .

In 5 It can be seen that the two switching positions 39 and 41 are reached at a rotation angle α of 90° and at a rotation angle of 240°. In 4 only switch position 41 is shown.

5 thus shows schematically the profile of the axial heights of the two shift gates 59 and 59 ' 4 via the angle of rotation α of the selector shaft 47.

At a rotation angle α 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 α, for example at an angle of rotation α of exactly 240°, but also in a tolerance range that extends over several degrees, for example about 10° or 20 ° extends. 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 α of 90°, the shift gate 59' has shifted the shift yoke 55' axially along the axis 51 to such an extent that 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 α 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 face-toothed toothed disks 65 and 67 mesh positively on the toothed side, have no relative movement to one another and transmit a torque in one direction of rotation. The second mode of operation occurs exclusively during shift 50 . The second mode does not occur when the bicycle is being ridden in a particular 39 or 41 shift position.

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 shifting process 50, two or more shiftable clutch devices 29 can be in the engaged state 31, but only one shiftable clutch device 29 can transmit the forces on a transmission shaft 3, 5 in this embodiment. The other switchable clutch device 29 runs freely.

6 shows a schematic representation of two selector shafts 47 as shown, for example, in 1 are shown. Depending on its angle of rotation α, each selector shaft 47 switches three switch positions 39, 41, 101 on the gear shaft 3, 5 assigned to it (cf. 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 related to 5 described, 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 switching position extends is in 6 drawn hatched at the respective selector 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 total of 9 gears of this bicycle bottom bracket gear, 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 shifting movements 38 take place simultaneously, it is possible to shift from one gear to any other gear very quickly.

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

Reference List

1

bicycle bottom bracket gear

3

input shaft

5

output shaft

7

intermediate shaft

9

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

gears

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

gear

44

Pair of meshing gears

45

rotary motion

46

Pair of meshing gears

47

shift shaft

49

actuator

50

switching process

51

Axis of the shift shaft

53

switching subunit

55, 55'

switching yoke

56

clutch body end of the shift yoke

57

switching cam

59, 59'

shift gate

61

clutch body

63

freewheel

65, 67, 65', 67'

toothed pulleys

69

gear case

71

warehouse

73, 75

gearing

77

pressing device

79

spring element

81

abutment

82

compression spring

83

recording

84

groove

85

circumferential direction

87

warehouse

89

career

91

ring element

92

locking ring

93

Game

95, 97

storage locations

99

elevated position

101

switching position

FA

release force

My

drive torque

Mouse

output torque

Xa, Xb

release movement

a

angle of rotation

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102004045364 B4 [0005]
• EN 102021101415 [0054]

Claims (22)

bicycle bottom bracket gear (1), with at least one transmission shaft (3, 5, 7) on which gear wheels (27, 34) each coupled to a switchable clutch device (29) are arranged, wherein the coupling devices (29) are designed to be switchable 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 a rotationally fixed manner in at least one direction of rotation of the respective transmission shaft (3, 5, 7) to the respective transmission shaft (3, 5, 7) and in the disengaged state the gearwheel (27, 34) of the coupling device (29) can rotate freely in relation to the respective transmission shaft (3, 5, 7), with at least one switching device (35, 37) for switching over the clutch devices of a transmission shaft (3, 5, 7), each gear shaft (3, 5, 7), on which gears (27, 34) coupled to a respective shiftable clutch device (29) are arranged, being assigned a different shifting device (35, 37), with each shifting device (35, 37) has at least two switching positions (39, 41) and is designed such that it can be transferred from one of the switching positions (39, 41) to another of the switching positions (39, 41) by means of a switching movement, each of the switching positions (39, 41) of a switching device (35, 37) corresponding to a different combination of the engaged and disengaged states (31, 33) of the clutch devices (29) of the transmission shaft (3, 5, 7) assigned to it, 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) can be reached by exactly one switching movement (38, 45), and wherein the at least one gear shaft (3, 5, 7) comprises 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 at least is an intermediate shaft (7) of the bicycle bottom bracket gear (1). Bicycle bottom bracket gear (1). claim 1 , 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. Bicycle bottom bracket gear (1). claim 1 or 2 , having at least two transmission shafts (3, 5, 7) on which gears (27, 34) coupled to a respective clutch device are arranged, and having at least two shifting devices (35, 37) for shifting the clutch devices (29) to one of the at least two transmission shafts (3, 5, 7). Bicycle bottom bracket gear (1). claim 3 , wherein the switching positions (39, 41, 101) of one of the at least two switching devices (35, 37) can be assumed independently of the switching positions (39, 41, 101) of another of the at least two switching devices (35, 37). Bicycle bottom bracket gear (1). claim 3 or 4 , The switching movements (38, 45) of one of the at least two switching devices (35, 37) being synchronized with the switching movements of at least one other of the at least two switching devices (35, 37). Bicycle bottom bracket gear (1) according to one of Claims 1 until 5 , wherein two gear shafts (3, 5, 7) are provided, on each of which gear wheels (27, 34) coupled with a switchable clutch device (29) are arranged, wherein one of the two gear shafts (3, 5, 7) has an input shaft ( 3) of the bicycle bottom bracket gear (1) and the other of the two gear shafts (3, 5, 7) is an output shaft (5) of the bicycle bottom bracket gear (1) and wherein between the two gear shafts (3, 5) there is an intermediate shaft (7) with gear wheels ( 27, 34) and wherein the gears (27, 34) each mesh with a gear (27, 34) of the input shaft (3) and/or with a gear (27, 34) of the output shaft (5). Bicycle bottom bracket gear (1) according to one of Claims 1 until 6 , wherein each switching device (35, 37) has an actuator (49) for generating the switching movement (38, 45). Bicycle bottom bracket gear (1) according to one of Claims 1 until 7 , wherein the switching movement (38, 45) is a rotary movement (45) and all switching positions (39, 41, 101) of a switching device (35, 37) are arranged within a full revolution. Bicycle bottom bracket gear (1). claim 8 , wherein a switching position (39, 41, 101) extends over a range of rotary movement, the range being greater than 10° and less than 90°. Bicycle bottom bracket gear (1) according to one of Claims 1 until 9 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 in each case a different coupling device (29) on the transmission shaft (3, 5, 7) assigned to this switching device (35, 37). Bicycle bottom bracket gear (1). claim 10 , wherein each shifting device (35, 37) for each of the clutch devices (29) of the transmission shaft (3, 5, 7) assigned to this shifting device (35, 37) comprises a shifting yoke (55) which is axially displaceable on the shifting shaft (47) and which a clutch body (61) of the respective clutch device (29) is connected in a shifting movement-transmitting manner. Bicycle bottom bracket gear (1). claim 11 at least one switching yoke (55) being provided with at least one switching cam (57) and the switching shaft (47) being provided with at least one switching gate (59) for the switching cam (57). Bicycle bottom bracket gear (1). claim 12 , wherein the switching yoke (55) is movably held on the switching shaft (47) at two axially spaced bearing points (95, 97) and wherein the switching gate (59) and the switching cam (57) are arranged between the two bearing points (95, 97). are. Bicycle bottom bracket gear (1) according to one of Claims 1 until 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), wherein the pressing device (77) is designed to engage the coupling body (61) with the to this coupling device (29) associated gear (27, 34), the pressing device (77) having at least one abutment (81) arranged axially immovably on the transmission shaft (3, 5, 7) and at least one between the abutment (81) and the clutch body (61) arranged spring element (79). Bicycle bottom bracket gear (1). Claim 14 , wherein the pressing device (77) has a plurality of spring elements (79) which are spaced apart from one another in a circumferential direction (85) of the transmission shaft (3, 5, 7) and are arranged between the at least one abutment (81) and the coupling body (61). . Bicycle bottom bracket gear (1) according to one of Claims 1 until 15 , wherein at least one coupling device (29) is designed as a freewheel (63). Bicycle bottom bracket gear (1). Claim 16 , wherein the switchable clutch device (29) designed as a disengageable freewheel (63) has two face-toothed toothed disks (95, 67). Bicycle bottom bracket gear (1). Claim 17 , wherein the toothed disks (95, 67) are separated from one another in the disengaged state (33) and pressed against one another by spring force in the engaged state (33). Bicycle bottom bracket gear (1) according to one of Claims 1 until 18 , wherein the bicycle bottom bracket 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 gear wheels (34) than the input shaft (3) and/or the output shaft ( 5) has. Bicycle bottom bracket gear (1) according to one of Claims 1 until 19 , wherein two of the transmission shafts (3, 5, 7) together have at least two pairs (44, 46) of gears (27, 34) meshing with each other, wherein the at least two pairs (44, 46) form different transmission ratios and wherein at least two of the Pairs (44, 46) belonging gears (27, 34) of a transmission shaft (3, 5, 7) have the same number of teeth. Bicycle bottom bracket gear (1) according to one of Claims 1 until 20 , wherein each gear (27, 34) of one and the same gear shaft (3, 5, 7) which is in mesh with the gear (27, 34) of another gear shaft (3, 5, 7) of the bicycle bottom bracket gear (1), has a coupling device (29). Bicycle bottom bracket gear (1) according to one of Claims 1 until 21 wherein the bicycle bottom bracket gear (1) has a plurality of gear shafts (3, 5, 7) and a plurality of selector shafts (47), the axes of rotation of which each span different planes in pairs that do not run parallel to one another.

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