DE102023211270B3 - Planetary bottom bracket gear for a bicycle or a pedelec - Google Patents

Abstract

A bottom bracket gear in planetary design for a bicycle or a pedelec (1) is proposed, with a pedal crank shaft (WAn) as the drive, with a transmission output shaft (WAb) as the output and with further shafts (W1, W2, W3, W4, W5, W6) and with a first transmission shifting group (3) and a second transmission shifting group (4), wherein the first transmission shifting group (3) comprises a first planetary gear set (RS1) and a second planetary gear set (RS2), to which four shifting elements (B1, K1, K2, K3) are assigned, wherein the second transmission shifting group (4) comprises at least a third planetary gear set (RS3). Furthermore, a bicycle or pedelec (1) with a bottom bracket gear is proposed.

Description

The present invention relates to a bottom bracket gear in planetary design for a bicycle or a pedelec with a transmission input shaft as the drive and a transmission output shaft as the output and with further shafts as well as with a first transmission shifting group and a second transmission shifting group, to which several planetary gear sets and shifting elements are assigned. The invention further relates to a bicycle or pedelec with the bottom bracket gear.

For example, from the publication DE 10 2021 204 634 B3 A transmission of this type is known in a crankcase for a bicycle. The transmission comprises three planetary gear sets, to which four shifting elements are assigned in order to realize at least four gears.

DE 10 2022 209 136 B3 (post-published) discloses a bottom bracket gear in planetary design for bicycles or pedelecs, which has several shafts, planetary gear sets and shifting elements in order to realize at least six gears. It comprises two partial gears that can be blocked by different shifting elements.

The present invention is based on the object of proposing a bottom bracket gear and a bicycle or pedelec with the bottom bracket gear, which have the lowest possible construction effort with improved properties compared to the prior art.

This object is achieved according to the invention by the objects having the features of patent claim 1 or 15. Advantageous and claimed further developments emerge from the subclaims and the description as well as the drawings.

Thus, a bottom bracket gear in planetary design is proposed for a bicycle or a pedelec. The bottom bracket gear has a crankshaft as the drive and a gear output shaft as the output as well as further shafts, wherein the output preferably takes place via a chain wheel, a belt wheel or the like. Furthermore, the bottom bracket transmission comprises a first gear shift group and a second gear shift group, wherein the first gear shift group comprises a first planetary gear set and a second planetary gear set, to which four shifting elements are assigned, wherein the second gear shift group comprises at least one third planetary gear set, to which at least two shifting elements are assigned, wherein a first shaft as the input shaft of the first gear shift group is connected to a second element of the first planetary gear set, wherein a fifth shaft as the output shaft of the first gear shift group can be connected to a third element of the first planetary gear set and to a first element of the second planetary gear set via a third shifting element, wherein the third element of the first planetary gear set is connected to the first element of the second planetary gear set, wherein the fifth shaft can be connected to a second element of the second planetary gear set via a fourth shifting element, wherein a first element of the first planetary gear set can be fixed to a housing or to a stationary component or the like via a first shifting element and can be connected to the second element of the second planetary gear set via a fifth shifting element, and wherein a third element of the second planetary gear set is fixed to the housing.

In this way, with the above-described connection of the first gear shift group in the proposed bottom bracket gear with only two planetary gear sets and only four shift elements, a particularly simple and compact design is achieved in the bottom bracket gear. In addition, there are particularly low component loads and an advantageously high gear efficiency due to the geometric transmission series in the bottom bracket gear compared to the known gear.

For the mechanical connection of elements, for example rotating elements or the like of the two planetary gear sets in the two transmission shift groups, in addition to the drive and output, further shafts or shaft-like elements are preferably used, whereby the term shaft does not exclusively refer to a cylindrical, rotatably mounted machine element for transmitting torque, but rather also to general connecting elements that connect the individual gear set elements to one another for torque transmission.

The axial order of the two gear shift groups can be swapped in the proposed bottom bracket gear. Accordingly, the first gear shift group is arranged between the gear input shaft or the pedal crank shaft and the gear output shaft of the bottom bracket gear before or after the second gear shift group. In an upstream arrangement of the first gear shift group, a pedal crank of the bottom bracket gear connected to the gear input or pedal crank shaft is connected to the first shaft as an input shaft of the first gear shift group and the fifth shaft of the first gear shift group is connected on the input side to the second gear shift group. It is possible, that the pedal crankshaft and the first shaft are designed as one piece or in multiple parts. In a downstream arrangement of the first gear shift group, the first shaft is connected to the second gear shift group on the output side and the fifth shaft of the first gear shift group is connected to the gearbox output shaft. It is possible that the gearbox output shaft and the fifth shaft are designed as one piece or in multiple parts.

In the proposed bottom bracket gear, a multi-stage second gear shift group of any design can be combined with the first gear shift group as a bottom bracket gear. Preferably, the second gear shift group can be designed as a two-speed gearbox or two-speed group and the first gear shift group as a four-speed gearbox or four-speed group, so that, for example, an eight-speed gearbox is implemented as a bottom bracket gear. However, other numbers of gears can also be implemented in the gear shift groups, so that the bottom bracket gear can also implement more or fewer than, for example, eight gears. Depending on the boundary conditions and requirements of the bottom bracket gear, gears can also be omitted. In this way, the gear set can be optimized for the required gear ratios (gear jumps, spread, etc.) or for the type of gear shifting, how many shifting elements are involved.

To connect the second gear shifting group, in order to achieve a particularly simple and compact design of the bottom bracket transmission, it can be provided that in the second gear shifting group a second element of the third planetary gear set is connected to the pedal crankshaft or to the fifth shaft of the first gear shifting group, that a first element of the third planetary gear set can be fixed to the housing via a second shifting element, and that a third element of the third planetary gear set is connected to the first shaft of the first gear shifting group or to the transmission output shaft.

To block the third planetary gear set in the second transmission shift group, two elements of the third planetary gear set can be connected to one another via the sixth shift element, resulting in a total of three different blocking variants.

Within the scope of the invention, when connecting the bottom bracket transmission, in which the first gear shifting group is connected upstream of the second gear shifting group, the pedal crank shaft is connected directly or via the first shaft to the second element of the first planetary gear set, the transmission output shaft is connected to the third element of the third planetary gear set, the first element of the first planetary gear set can be fixed to the housing via a second shaft and via the first shifting element and can be connected to the second element of the second planetary gear set via the fifth shifting element and via a fourth shaft, the third element of the second planetary gear set is fixed to the housing via a fixed housing connection, the second element of the third planetary gear set can be connected to the third element of the first planetary gear set and to the first element of the second planetary gear set via the fifth shaft and via the third shifting element and via a third shaft, and to the second element of the second planetary gear set via the fourth shifting element and via the fourth shaft, the third element of the first planetary gear set being connected to the third element of the first planetary gear set via the third shaft. the first element of the second planetary gear set, and that the first element of the third planetary gear set RS3 can be fixed to the housing via a sixth shaft and via the second switching element and can be connected to the third element of the third planetary gear set via the sixth switching element for blocking the third planetary gear set.

Furthermore, the connection of the proposed bottom bracket transmission, in which the second gear shift group is connected upstream of the first gear shift group, results in the pedal crankshaft being connected to the second element of the third planetary gear set, the transmission output shaft being connectable directly or via the fifth shaft and via the third shifting element and via a third shaft to the third element of the first planetary gear set and to the first element of the second planetary gear set, and via the fourth shifting element and via a fourth shaft to the second element of the second planetary gear set, the third element of the first planetary gear set being connected via the third shaft to the first element of the second planetary gear set, the first element of the first planetary gear set being fixable to the housing via a second shaft and via the first shifting element and being connectable to the second element of the second planetary gear set via the fifth shifting element and via the fourth shaft, the third element of the second planetary gear set being fixed to the housing via a fixed housing connection, the first element of the third planetary gear set being connected via a sixth shaft and can be fixed to the housing via the second switching element and can be connected to the third element of the third planetary gear set via the sixth switching element for blocking the third planetary gear set, and that the third element of the third planetary gear set is connected to the second element of the first planetary gear set via the first shaft.

Within the scope of the invention, the proposed bottom bracket transmission with the two transmission shift groups provides that the shifting elements provided can be designed as brakes, freewheel brakes, clutches and/or freewheels. An advantageous embodiment of the invention provides that the first shifting element and the second shifting element are each designed as a positive-locking brake, that the third shifting element is designed as a positive-locking clutch, and/or that the fourth shifting element and fifth shifting element as well as the sixth shifting element are each designed as a freewheel.

The switching elements designed as brakes and clutches are preferably designed as positive-locking switching elements, for example as inexpensive brake or switching claws or the like, for example with a toothed brake ring and a corresponding switching pawl. Brakes as switching elements have the advantage that they can be easily reached for operation from the outside. In the case of clutches designed as freewheels, it is advantageous if the brakes are designed, for example, as one-sided brakes in order to prevent the gear from jamming when the direction of rotation on the drive or output is reversed. Freewheels that cannot be actively switched or actuated are preferably used as freewheels. This has the advantage that no switching operation is required for the passive switching elements. The non-actuable freewheel transmits a torque when it locks in the blocking direction state. No torque is transmitted in the opposite direction of rotation because the freewheel does not lock in the overrunning drive state. However, it is conceivable that actively switchable freewheels or actively switchable freewheel brakes could also be used.

A preferred embodiment of the invention can provide that at least one of the planetary gear sets provided is designed as a minus planetary gear set, which results in an arrangement that is particularly space-efficient. It is also conceivable that one of the planetary gear sets is designed as a plus planetary gear set.

A minus planetary gear set can preferably be converted into a plus planetary gear set if the planet gear carrier and ring gear connections on this gear set are swapped around and the amount of the stationary gear ratio is increased by 1. A minus planetary gear set has planetary gears which are rotatably mounted on its planet gear carrier and which mesh with the sun gear and the ring gear of this planetary gear set, so that when the planet gear carrier is held in place and the sun gear is rotating, the ring gear rotates in the opposite direction to the direction of rotation of the sun gear. A plus planetary gear set has inner and outer planet gears which are rotatably mounted on its planet gear carrier and which mesh with one another, with the sun gear of this planetary gear set meshing with the inner planet gears and the ring gear of this planetary gear set meshing with the outer planet gears, so that when the planet gear carrier is held in place and the sun gear is rotating, the ring gear rotates in the same direction as the direction of rotation of the sun gear.

For the expert, this means that in the case of the individual gear sets designed as a minus planetary gear set, a first element or gear set element is designed as a sun gear, a second element as a planetary gear carrier or web and a third element as a ring gear. Furthermore, this means that in the case of an individual gear set designed as a plus planetary gear set, the first element is designed as a sun gear, the second element as a ring gear and the third element as a planetary gear carrier or web.

Furthermore, with the proposed bottom bracket gear, it is conceivable that stepped planets are used in both a minus planetary gear set and a plus planetary gear set. With a minus stepped planetary gear set, the assignment of the elements or gear set elements remains the same as with a conventional minus planetary gear set. With a plus stepped planetary gear set, it is provided that the first element is designed as the first sun gear, the second element as the second sun gear and the third element as the planet gear carrier, or that the first element is designed as the first ring gear, the second element as the second ring gear and the third element as the planet gear carrier.

In order to further optimize the control of the proposed bottom bracket gear, it is provided that at least one torque sensor or the like is provided on the drive and/or on the output.

In order to electrically support the drive in the proposed bottom bracket transmission, at least one electric machine or the like can be connected or connectable to the drive or to the pedal crankshaft or transmission input shaft and/or to the output or to the transmission output shaft or can be coupled firmly or detachably. Preferably, the electric machine can be arranged axially parallel to the pedal crankshaft or transmission input shaft, while the planetary gear sets are arranged coaxially to the pedal crankshaft or transmission input shaft.

A further aspect of the present invention claims a bicycle or pedelec with the bottom bracket gear described above. The advantages already described and further advantages arise.

The present invention is further explained below with reference to the drawings.

• 1 eine schematische Prinzipansicht eines erfindungsgemäßen Tretlagergetriebes an einem Fahrrad oder einem Pedelec mit einer einer zweiten Getriebeschaltgruppe vorgeschalteten ersten Getriebeschaltgruppe;
• 2 eine schematische Prinzipansicht des erfindungsgemäßen Tretlagergetriebes mit der der zweiten Getriebeschaltgruppe nachgeschalteten ersten Getriebeschaltgruppe;
• 3 ein Schaltschema mit vier schaltbaren Gängen der ersten Getriebeschaltgruppe bei dem Tretlagergetriebe;
• 4 eine schematische Prinzipansicht eines Planetenradsatzes als Minus-Planetenradsatz;
• 5 eine schematische Prinzipansicht eines Planetenradsatzes als Plus-Planetenradsatz;
• 6 eine schematische Prinzipansicht eines Planetenradsatzes als Minus-Stufenplanetenradsatz;
• 7 eine schematische Prinzipansicht eines Planetenradsatzes als Plus-Stufenplanetenradsatz mit zwei Sonnenrädern;
• 8 eine schematische Prinzipansicht eines Planetenradsatzes als Plus-Stufenplanetenradsatz mit zwei Hohlrädern;
• 9 eine schematische Prinzipansicht des Tretlagergetriebes mit einer Ausführung der der ersten Getriebeschaltgruppe als Vierganggetriebe nachgeschalteten zweiten Getriebeschaltgruppe als Zweiganggetriebe;
• 10 eine schematische Prinzipansicht des Tretlagergetriebes mit einer Ausführung der der ersten Getriebeschaltgruppe als Vierganggetriebe vorgeschalteten zweiten Getriebeschaltgruppe als Zweiganggetriebe;
• 11 ein Schaltschema des achtgängigen Tretlagergetriebes gemäß der 9 und 10;
• 12 eine schematische Prinzipansicht des Tretlagergetriebes gemäß 9 mit einem beispielhaft angedeuteten Drehmomentsensor am Antrieb;
• 13 eine schematische Prinzipansicht des Tretlagergetriebes gemäß 12 mit einer beispielhaft am Antrieb angeordneten elektrischen Maschine;
• 14 eine schematische Prinzipansicht des Tretlagergetriebes gemäß 12 mit einer beispielhaft am Abtrieb angeordneten elektrischen Maschine; und
• 15 eine schematische Prinzipansicht des Tretlagergetriebes gemäß 12 mit einem Freilauf vor der Tretkurbelwelle.

They show:

• 1 a schematic principle view of a bottom bracket gear according to the invention on a bicycle or a pedelec with a first gear shift group connected upstream of a second gear shift group;
• 2 a schematic principle view of the bottom bracket transmission according to the invention with the first transmission group connected downstream of the second transmission group;
• 3 a shifting pattern with four switchable gears of the first gear group in the bottom bracket gearbox;
• 4 a schematic principle view of a planetary gear set as a minus planetary gear set;
• 5 a schematic principle view of a planetary gear set as a plus planetary gear set;
• 6 a schematic principle view of a planetary gear set as a minus-step planetary gear set;
• 7 a schematic principle view of a planetary gear set as a plus-step planetary gear set with two sun gears;
• 8 a schematic principle view of a planetary gear set as a plus-step planetary gear set with two ring gears;
• 9 a schematic principle view of the bottom bracket transmission with an embodiment of the second transmission group as a two-speed transmission, downstream of the first transmission group as a four-speed transmission;
• 10 a schematic principle view of the bottom bracket transmission with an embodiment of the second transmission group as a two-speed transmission, which is connected upstream of the first transmission group as a four-speed transmission;
• 11 a shifting diagram of the eight-speed bottom bracket transmission according to the 9 and 10 ;
• 12 a schematic principle view of the bottom bracket gear according to 9 with an example torque sensor on the drive;
• 13 a schematic principle view of the bottom bracket gear according to 12 with an electric machine arranged as an example on the drive;
• 14 a schematic principle view of the bottom bracket gear according to 12 with an electric machine arranged at the output, for example; and
• 15 a schematic principle view of the bottom bracket gear according to 12 with a freewheel in front of the crank shaft.

In the 1 to 15 Various design variants and versions or switching schemes of a bottom bracket gear according to the invention in planetary design are shown merely as examples. 1 shows an example of a bicycle or Pedelec 1 with the bottom bracket gear, only schematically indicated.

The bottom bracket gear is shown in a housing or bottom bracket housing 2 with a pedal crank with pedals as a pedal crankshaft WAn, wherein the pedal crankshaft WAn is connected on the input side to one of the gear shift groups 3, 4. The bottom bracket gear also comprises a gear output shaft WAb as an output with a chain or belt wheel (not shown in any more detail), which is connected on the output side to one of the gear shift groups 3, 4. The bottom bracket transmission comprises a multi-stage first transmission shifting group 3 and a multi-stage second transmission shifting group 4, wherein the first transmission shifting group 3 has a first planetary gear set RS1 and a second planetary gear set RS2, to which a first shifting element B1 as a positive brake, a third shifting element K1 as a positive clutch, a fourth shifting element K2 as a freewheel and a fifth shifting element K3 as a freewheel are assigned, and wherein the second transmission shifting group 4 has a third planetary gear set RS3, to which a second shifting element B2 as a positive brake and a sixth shifting element K4 as a freewheel are assigned. The two transmission shifting groups 3, 4 essentially form two partial transmissions that can be connected to one another in any order with respect to the direction of power flow between the pedal crankshaft WAn and the transmission output shaft WAb.

Irrespective of the respective design variants, the bottom bracket transmission is provided with a first shaft W1 as the input shaft of the first gear shift group 3 being connected to a second element of the first planetary gear set RS1, a fifth shaft W5 as the output shaft of the first gear shift group 3 being connectable to a third element of the first planetary gear set RS1 and to a first element of the second planetary gear set RS2 via a third shifting element K1, the third element of the first planetary gear set RS1 being connected to the first element of the second planetary gear set RS2, the fifth shaft W5 being connectable to a second element of the second planetary gear set RS1 via a fourth shifting element K2. planetary gear set RS2, that a first element of the first planetary gear set RS1 can be fixed to the housing 2 via a first switching element B1 and can be connected to the second element of the second planetary gear set RS2 via a fifth switching element K3, and that a third element of the second planetary gear set RS2 is fixed to the housing 2.

In the 1 and 2 as well as 9 and 10 and 12 to 15, the planetary gear sets RS1, RS2, RS3 are each designed as minus planetary gear sets with a low installation space. It is intended that the first element in each case is a sun gear SR1, SR2, SR3, the second element is a web or planetary gear carrier PT1, PT2, PT3 and the third element is a ring gear HR1, HR2, HR3 for the planetary gear sets RS1, RS2, RS3.

In 1 A variant of the bottom bracket transmission is shown in which the first gear shift group 3 is connected upstream of the second gear shift group 4. In detail, the first variant according to 1 provided that the first shaft W1 as the input shaft of the first gear shift group 3 is connected to the pedal crankshaft WAn or is formed in one piece with it, that the first shaft W1 is connected to the planetary gear carrier PT1 of the first planetary gear set RS1, that the fifth shaft W5 is connected on the input side to the second gear shift group 4, that the fifth shaft W5 as the output shaft of the first gear shift group 3 can be connected to the ring gear HR1 of the first planetary gear set RS1 and to the sun gear SR2 of the second planetary gear set RS2 via a third shaft W3 when the third shifting element K1 is closed, wherein the ring gear HR1 of the first planetary gear set RS1 is connected to the sun gear SR2 of the second planetary gear set RS2 via the third shaft W3, wherein the fifth shaft W5 can be connected to the planetary gear carrier PT2 of the second planetary gear set RS2 via a fourth shaft W4 when the fourth shifting element K2 is locked, wherein the sun gear SR1 of the first Planetary gear set RS1 can be fixed to the housing 2 via a second shaft W2 when the first switching element B1 is closed and can be connected to the planet gear carrier PT2 of the second planetary gear set RS2 via the fourth shaft W4 when the fifth switching element K3 is locked, and wherein the ring gear HR2 of the second planetary gear set RS2 is fixed to the housing 2 via a fixed housing connection W0.

In 2 A variant of the bottom bracket transmission is shown in which the first gear shift group 3 is connected downstream of the second gear shift group 4. In detail, the variant according to 2 provided that the pedal crankshaft WAn is connected on the input side to the second gear shift group 4, that the first shaft W1 as the input shaft of the first gear shift group 3 is connected on the output side to the second gear shift group 4, that the first shaft W1 is connected to the planetary gear carrier PT1 of the first planetary gear set RS1, that the fifth shaft W5 as the output shaft of the first gear shift group 3 is connected to the gear output shaft WAb or is formed as one piece with it, that the fifth shaft W5 as the output shaft of the first gear shift group 3 can be connected to the ring gear HR1 of the first planetary gear set RS1 and to the sun gear SR2 of the second planetary gear set RS2 via the third shaft W3 when the third shifting element K1 is closed, wherein the ring gear HR1 of the first planetary gear set RS1 is connected via the third shaft W3 to the sun gear SR2 of the second planetary gear set RS2, that the fifth shaft W5 is connected to the fourth shaft W4 with the fourth shifting element K2 locked the planet gear carrier PT2 of the second planetary gear set consisting of two, that the sun gear SR1 of the first planetary gear set RS1 can be fixed to the housing 2 via the second shaft W2 when the first switching element B1 is closed and can be connected to the planet gear carrier PT2 of the second planetary gear set RS2 via the fourth shaft W4 when the fifth switching element K3 is locked, and that the ring gear HR2 of the second planetary gear set RS2 is fixed to the housing 2 via the fixed housing connection W0.

In 3 a shift diagram for the first gear shift group 3 is shown as a four-speed gearbox. This means that four gears V1, V2, V3, V4 can be achieved with the first gear shift group 3. The shift elements B1, K1, K2, K3 used for the respective gear V1, V2, V3, V4 are specified in the shift diagram. An X for the freewheels K2, K3 as shift elements in the shift diagram means that the freewheels are locked. This works automatically without external activation. Furthermore, an X for a brake B1 or a clutch K1 as a shift element in the shift diagram means that the brake B1 or the clutch K1 is closed. This works via a suitable actuator. An empty field for the freewheels K2, K3 means that they are not locked. An empty field for the brake or clutch B1, K1 means that they are open.

In detail, the circuit diagram according to 3 that in order to realize or switch a first gear V1, the fourth switching element K2 designed as a freewheel and the fifth switching element K3 designed as a freewheel are locked, that in order to switch a second gear V2, the first switching element B1 designed as a brake is closed and the fourth switching element K2 designed as a freewheel is locked, that in order to switch a third gear V3, the third switching element K1 designed as a clutch is closed and the fifth switching element K3 designed as a freewheel is blocked, and/or that to engage a fourth gear V4, the first switching element B1 designed as a brake and the third switching element K1 designed as a clutch are closed.

In 4 As an example, a minus planetary gear set is shown in which the first element is designed as a sun gear 1-SR, the second element as a planet gear carrier 2-PT and the third element as a ring gear 3-HR.

In 5 As an example, a plus planetary gear set is shown in which the first element is designed as a sun gear 1-SR, the second element as a ring gear 2-HR and the third element as a planet gear carrier 3-PT.

In 6 As an example, a minus-step planetary gear set is shown in which the first element is designed as a sun gear 1-SR, the second element as a planet gear carrier 2-PT and the third element as a ring gear 3-HR.

In 7 As an example, a plus-step planetary gear set is shown in which the first element is designed as the first sun gear 1-SRA, the second element as the second sun gear 2-SRB and the third element as the planet gear carrier 3-PT.

In 8 Another embodiment of a plus-step planetary gear set is shown as an example, in which the first element is designed as the first ring gear 1-HRA, the second element as the second ring gear 2-HRB and the third element as the planet gear carrier 3-PT.

The 4 to 8 The possible designs shown using a planetary gear set can be implemented on the concrete planetary gear sets RS1, RS2, RS3 of the bottom bracket transmission according to the invention.

In the 9 and 10 The bottom bracket transmission is shown as an example with a first gear shift group 3 as a four-speed transmission group and with a second gear shift group 4 as a two-speed transmission group. The two representations according to 9 and 10 differ only in that the axial order of the two gear shift groups 3, 4 are swapped. In 9 the first gear shift group 3 is connected upstream of the second gear shift group 4, while in 10 the second gearshift group 4 is connected upstream of the first gearshift group 3.

In detail, the connection of the second gear shift group 4 to the first gear shift group 3 in 9 provided that in the second transmission shift group 4 the planetary gear carrier PT3 of the third planetary gear set RS3 is connected to the fifth shaft W5 as the output shaft of the first transmission shift group 3, that the sun gear SR3 of the third planetary gear set RS3 can be fixed to the housing 2 via a sixth shaft W6 when the second shift element B2 is closed, that the ring gear HR3 of the third planetary gear set RS3 is connected to the transmission output shaft WAb, and that as one of the possible blocking variants of the third planetary gear set RS3, the sun gear SR3 of the third planetary gear set RS3 is connected to the ring gear HR3 of the third planetary gear set RS3 when the sixth shift element K4 is locked. The connections of the two planetary gear sets RS1 and RS2 in the first transmission shift group 3 have already been described above.

In detail, the connection of the second gear shift group 4 to the first gear shift group 3 in 10 provided that the planetary gear carrier PT3 of the third planetary gear set RS3 is connected to the pedal crankshaft WAn, that the ring gear HR3 of the third planetary gear set RS3 is connected to the first shaft W1 as the input shaft of the first transmission shift group 3, that the sun gear SR3 of the third planetary gear set RS3 can be fixed to the housing 2 via the sixth shaft W6 when the second shift element B2 is closed, and that as one of the possible blocking variants of the third planetary gear set RS3, the sun gear SR3 of the third planetary gear set RS3 is connected to the ring gear HR3 of the third planetary gear set RS3 when the sixth shift element K4 is locked. The connections of the two planetary gear sets RS1 and RS2 in the first transmission shift group 3 have already been described above.

In 11 is a shift diagram for the bottom bracket gear with the first gear shift group 3 as a four-speed gearbox and with the second gear shift group 4 as a two-speed gearbox. This means that 4 x 2, i.e. eight gears V1, V2, V3, V4, V5, V6, V7, V8, can be implemented. The shift elements B1, B2, K1, K2, K3, K4 used for the respective gear V1, V2, V3, V4, V5, V6, V7, V8 are shown in the shift diagram. An X for the freewheels K2, K3, K4 as shift elements in the shift diagram means that the freewheels are locked. This works automatically without external operation. Furthermore, an X for a brake B1, B2 or a clutch K1 as a shift element in the shift diagram means that the brake B1, B2 or the clutch K1 is closed. This works via a suitable actuator. An empty field for the freewheels K2, K3, K4 means that they are not locked. An empty field for the brakes or clutch B1, B2, K1 means that they are open.

In detail, the circuit diagram according to 11 , that in order to implement or shift a first gear V1, the fourth shifting element K2, the fifth shifting element K3, the sixth shifting element K4, the freewheel, are locked; that in order to shift a second gear V2, the first shifting element B1, the brake, is closed and the fourth shifting element K2, the freewheel, and the sixth shifting element K4 are locked; that in order to shift a third gear V3, the second shifting element B2, the brake, is closed and the fourth shifting element K2, the freewheel, and the fifth shifting element K3 are locked; that in order to shift a fourth gear V4, the first shifting element B1, the brake, and the second shifting element B2 are closed and the fourth shifting element K2 is locked; that in order to shift a fifth gear V5, the third shifting element K1, the clutch, is closed and the fifth shifting element K4 is locked. Switching element K3 and the sixth switching element K4 designed as a freewheel lock, so that to shift a sixth gear V6 the first switching element B1 designed as a brake and the third switching element K1 designed as a clutch are closed and the sixth switching element K4 designed as a freewheel locks, so that to shift a seventh gear V7 the second switching element B2 designed as a brake and the third switching element K1 designed as a clutch are closed and the fifth switching element K3 designed as a freewheel locks, and/or so that to shift an eighth gear V8 the first switching element B1 designed as a brake, the second switching element B2 designed as a brake and the third switching element K1 designed as a clutch are closed.

In 12 is an embodiment of the bottom bracket gear according to the invention based on 9 shown, in which a torque sensor 5 is connected or can be connected to the pedal crankshaft or to the transmission input shaft WAn. For example, a disk-shaped torque sensor 5 can be arranged at the transmission input. However, the torque sensor 5 can also be designed in a different way.

In the 13 and 14 is an embodiment of the bottom bracket gear according to the invention based on 12 with an additional electric machine EM. The electric machine EM can be connected to the crankshaft WAn, as shown in 13 It is also conceivable that the electric machine EM is connected to the transmission output shaft WAb, as shown in 14 is shown. The electric machine EM is preferably arranged axially parallel to the pedal crankshaft or transmission input shaft WAn. However, a coaxial arrangement of the electric machine EM to the pedal crankshaft would also be possible. Irrespective of this, it is advantageous to connect the electric machine EM via a freewheel F0 or the like so that no losses are caused by the rotating electric machine EM when operating without the electric machine EM.

In 15 is an embodiment of the bottom bracket gear according to the invention based on 12 with an additional freewheel F1 between the pedal crank and the gear input of the bottom bracket gear. In this way, the freewheel can open when pedaling is interrupted and decouples the pedal crank from the inertia masses of the gear set and in particular the electric machine EM, so that no inertial forces are felt on the pedal.

reference sign

1

bicycle or pedelec

2

housing or bottom bracket shell

3

first gearshift group

4

second gearshift group

5

torque sensor

EM

electric machine

F0

freewheel for electric machine

F1

additional freewheel

SR1

sun gear of the first planetary gear set

PT1

planetary gear carrier of the first planetary gear set

HR1

ring gear of the first planetary gear set

SR2

sun gear of the second planetary gear set

PT2

planetary gear carrier of the second planetary gear set

HR2

ring gear of the second planetary gear set

SR3

sun gear of the third planetary gear set

PT3

planetary gear carrier of the third planetary gear set

HR3

ring gear of the third planetary gear set

RS1

first planetary gear set

RS2

second planetary gear set

RS3

third planetary gear set

WAN

transmission input shaft or crankshaft

WAb

transmission output shaft

W1

first wave

W2

second wave

W3

third wave

W4

fourth wave

W5

fifth wave

W6

sixth wave

W0

fixed housing connection

V1

first gear of the bottom bracket transmission

V2

second gear of the bottom bracket gear

V3

third gear of the bottom bracket gear

V4

fourth gear of the bottom bracket transmission

V5

fifth gear of the bottom bracket transmission

V6

sixth gear of the bottom bracket gearbox

V7

seventh gear of the bottom bracket transmission

V8

eighth gear of the bottom bracket gear

B1

first switching element designed as a brake

B2

second switching element designed as a brake

K1

third switching element designed as a clutch

K2

fourth switching element designed as a freewheel

K3

fifth switching element designed as a freewheel

K4

sixth switching element designed as a freewheel

1-SR

first element as a sun wheel

2-PT

second element as planetary gear carrier

2-HR

second element as a ring gear

3-HR

third element as a ring gear

3-PT

third element as planetary gear carrier

1-SRA

first element as the first sun gear

2-SRB

second element as second sun gear

1-HRA

first element as the first ring gear

2-HRB

first element as second ring gear

Claims (15)

Bottom bracket gear in planetary design for a bicycle or a pedelec (1), with a pedal crank shaft (WAn) as a drive, with a transmission output shaft (WAb) as an output and with further shafts (W1, W2, W3, W4, W5, W6) as well as with a first transmission shifting group (3) and a second transmission shifting group (4), wherein the first transmission shifting group (3) comprises a first planetary gear set (RS1) and a second planetary gear set (RS2), to which four shifting elements (B1, K1, K2, K3) are assigned, wherein the second transmission shifting group (4) comprises at least a third planetary gear set (RS3), to which at least two shifting elements (B2, K4) are assigned, wherein a first shaft (W1) as an input shaft of the first transmission shifting group (3) is connected to a second element of the first planetary gear set (RS1), wherein a fifth shaft (W5) as an output shaft of the first transmission shifting group (3) is connected via a third shifting element (K1) to a third element of the first planetary gear set (RS1) and can be connected to a first element of the second planetary gear set (RS2), wherein the third element of the first planetary gear set (RS1) is connected to the first element of the second planetary gear set (RS2), wherein the fifth shaft (W5) can be connected to a second element of the second planetary gear set (RS2) via a fourth switching element (K2), wherein a first element of the first planetary gear set (RS1) can be fixed to a housing (2) via a first switching element (B1) and can be connected to the second element of the second planetary gear set (RS2) via a fifth switching element (K3), and where a third element of the second planetary gear set (RS2) is fixed to the housing (2). bottom bracket gear after claim 1 , characterized in that the first transmission shift group (3) is connected upstream or downstream of the second transmission shift group (4). Bottom bracket transmission according to one of the preceding claims, characterized in that in the second gear shifting group a second element of the third planetary gear set (RS3) is connected to the pedal crank shaft (WAn) or to the fifth shaft (W5) of the first gear shifting group (3), that a first element of the third planetary gear set (RS3) can be fixed to the housing (2) via a second shifting element (B2), and that a third element of the third planetary gear set (RS3) is connected to the first shaft (W1) of the first gearbox shift group (3) or with the gearbox output shaft (WAb). Bottom bracket transmission according to one of the preceding claims, characterized in that in the second transmission shifting group (4) for blocking the third planetary gear set (RS3) two elements of the third planetary gear set (RS3) can be connected to one another via the sixth shifting element (K4). Bottom bracket transmission according to one of the preceding claims, characterized in that the pedal crank shaft (WAn) is connected directly or via the first shaft (W1) to the second element of the first planetary gear set (RS1), that the transmission output shaft (WAb) is connected to the third element of the third planetary gear set (RS3), that the first element of the first planetary gear set (RS1) can be fixed to the housing (2) via a second shaft (W2) and via the first switching element (B1) and can be connected to the second element of the second planetary gear set (RS2) via the fifth switching element (K3) and via a fourth shaft (W4), that the third element of the second planetary gear set (RS2) is fixed to the housing (2) via a fixed housing connection (W0), that the second element of the third planetary gear set (RS3) can be connected to the third element of the first planetary gear set (RS3) via the fifth shaft (W5) and via the third switching element (K1) and via a third shaft (W3). planetary gear set (RS1) and with the first element of the second planetary gear set (RS2) and via the fourth switching element (K2) and via the fourth shaft (W4) with the second element of the second planetary gear set (RS2), wherein the third element of the first planetary gear set (RS1) is connected via the third shaft (W3) with the first element of the second planetary gear set (RS2), and that the first element of the third planetary gear set (RS3) can be fixed to the housing (2) via a sixth shaft (W6) and via the second switching element (B2) and can be connected via the sixth switching element (K4) to the third element of the third planetary gear set (RS3) for blocking the third planetary gear set (RS3). Bottom bracket gear according to one of the Claims 1 until 5 , characterized in that the pedal crankshaft (WAn) is connected to the second element of the third planetary gear set (RS3), that the transmission output shaft (WAb) can be connected directly or via the fifth shaft (W5) and via the third switching element (K1) and via a third shaft (W3) to the third element of the first planetary gear set (RS1) and to the first element of the second planetary gear set (RS2) and via the fourth switching element (K2) and via a fourth shaft (W4) to the second element of the second planetary gear set (RS2), wherein the third element of the first planetary gear set (RS1) is connected via the third shaft (W3) to the first element of the second planetary gear set (RS2), that the first element of the first planetary gear set (RS1) can be fixed to the housing (2) via a second shaft (W2) and via the first switching element (B1) and can be connected via the fifth switching element (K3) and via the fourth shaft (W4) to the second element of the second planetary gear set (RS2), that the third element of the second planetary gear set (RS2) is fixed to the housing (2) via a fixed housing connection (W0), that the first element of the third planetary gear set (RS3) is fixable to the housing (2) via a sixth shaft (W6) and via the second switching element (B2) and is connectable to the third element of the third planetary gear set (RS3) via the sixth switching element (K4) for blocking the third planetary gear set (RS3), and that the third element of the third planetary gear set (RS3) is connected to the second element of the first planetary gear set (RS1) via the first shaft (W1). Bottom bracket transmission according to one of the preceding claims, characterized in that the first switching element (B1) and the second switching element (B2) are each designed as a positive-locking brake, that the third switching element (K1) is designed as a positive-locking clutch, and/or that the fourth switching element (K2) and fifth switching element (K3) as well as the sixth switching element (K4) are each designed as a freewheel. Bottom bracket transmission according to one of the preceding claims, characterized in that the first planetary gear set (RS1) and/or the second planetary gear set (RS2) and/or the third planetary gear set (RS3) are each designed as minus planetary gear sets. bottom bracket gear after claim 8 , characterized in that in a minus planetary gear set the first element is designed as a sun gear (SR1, SR2, SR3), the second element as a planet gear carrier (PT1, PT2, PT3) and the third element as a ring gear (HR1, HR2, HR3). Bottom bracket transmission according to one of the preceding claims, characterized in that the first planetary gear set (RS1) and/or the second planetary gear set (RS2) and/or the third planetary gear set (RS3) are each designed as plus planetary gear sets. bottom bracket gear after claim 10 , characterized in that in a plus planetary gear set the first element is designed as a sun gear (SR1, SR2, SR3), the second element as a ring gear (HR1, HR2, HR3) and the third element as a planet gear carrier (PT1, PT2, PT3). Bottom bracket transmission according to one of the preceding claims, characterized in that a torque sensor (5) is connected to the pedal crank shaft (WAn). Bottom bracket transmission according to one of the preceding claims, characterized in that at least one electrical machine (EM) is connected or can be connected to the pedal crank shaft (WAn) or to the transmission output shaft (WAb). bottom bracket gear after claim 13 , characterized in that the electric machine (EM) is arranged axially parallel to the pedal crankshaft (WAn). Bicycle or Pedelec (1) with the bottom bracket gear according to one of the preceding claims.

Images