Gearbox and bottom bracket for a bicycle

Abstract

Transmission for a bicycle, with a manual transmission (1) which is operatively connectable to a bottom bracket crankshaft (2) and has a manual transmission output shaft (3), and with an electric machine (5), wherein the transmission has a superposition transmission (4) which is drive-technically connected downstream of the manual transmission (1), wherein the electric machine (5) is operatively connected or operatively connectable to an element of the superposition transmission (4) and the manual transmission output shaft (3) is operatively connected to another element of the superposition transmission (4), characterized in that the manual transmission (1) has a first planetary gear set (PS1) and a first shifting element (S1) assigned to the first planetary gear set (PS1) and / or that the manual transmission (1) has a second planetary gear set (PS2) and a second shifting element (S2) assigned to the second planetary gear set (PS2).

Description

[0001] The invention relates to a transmission for a bicycle, comprising a manual transmission which is operatively connectable to a bottom bracket crankshaft and has a manual transmission output shaft, and an electric machine.

[0002] The invention also relates to a bottom bracket with such a gearing. Furthermore, the invention relates to a bicycle with the bottom bracket or the gearing.

[0003] A variety of bicycles are known from the prior art that utilize an electric motor in addition to a manual transmission. A wide variety of arrangements of the manual transmission and the electric motor are known. For example, designs are known in which the electric motor is located in the bottom bracket and the manual transmission is located on the rear wheel. Furthermore, designs are known in which the electric motor and the manual transmission are located in the bottom bracket. In these cases, it is known to connect the electric motor upstream of the manual transmission. One such design is known, for example, from WO 2015 / 024 701 A1.

[0004] The problem with the current transmission is that the torque generated by the electric motor is transferred to the components of the manual transmission. This increases wear on the components of the manual transmission, resulting in high maintenance costs.

[0005] From the publication DE 10 2013 206 713 A1, an electric bicycle that can be driven by both motor and muscle power is known. It has a crank mechanism with a bottom bracket shaft, a chainring, an electric drive, and a continuously variable friction transmission for continuously varying the gear ratio. The electric bicycle includes a planetary gear system through which the electric drive is connected to the chainring.

[0006] The document JP H09 - 189 346 A discloses a bicycle with an auxiliary motor, in which a manual first drive source is coupled via the pedal shaft to a first planetary gear and a mechanical second drive source is coupled to a second planetary gear, wherein the output elements of the two planetary gears are each connectable via a coupling element to an output element for driving the bicycle.

[0007] DE 40 27 365 A1 describes a bicycle with a combined pedal and motor drive. A pedal crank bearing of the bicycle is equipped with a planetary gear system, with a first gear shaft driven by the pedal cranks and a second gear shaft driven by a motor sprocket, so that the superimposed torque is transmitted to a third shaft, which, as the output shaft, is frictionally coupled to a sprocket to drive the bicycle.

[0008] From the publication CN 19 87 102 191 A, another bicycle with two drives is known, where the drive sources are superimposed via planetary gears.

[0009] The document DE 10 2014 000 898 A1 describes a bicycle drive unit which is used with a bicycle coaster brake.

[0010] The object of the invention is therefore to provide a transmission that does not require high maintenance costs.

[0011] The problem is solved by each subject matter of the independent patent claims.

[0012] The transmission has a superposition gear arranged downstream of the manual transmission, wherein the electric machine is operatively connected or operatively connectable to an element of the superposition gear and the manual transmission output shaft is operatively connected to another element of the superposition gear.

[0013] The transmission according to the invention has the advantage that, due to the downstream drive connection of the electric motor, no load is exerted on the components of the manual transmission. In particular, the torque provided by the electric motor is introduced into the superposition gear without placing any load on the components of the manual transmission. Due to the reduced load on the components of the manual transmission, wear on the components is reduced, thereby increasing their service life. This leads to reduced maintenance requirements for the transmission.

[0014] A further advantage of the transmission according to the invention is that it is highly efficient and that, thanks to the manual transmission, an open, dirt-sensitive derailleur is no longer necessary. A belt drive can be used to transmit power to the rear wheel. Furthermore, the simple design of the manual transmission, described in more detail below, allows for a very narrow transmission design, which is advantageous because space in a bottom bracket is limited.

[0015] The provision of the superposition gearbox and the electric motor offers the advantage that speed ratios between the mechanical gears can be provided by appropriately controlling the electric motor. In particular, when controlling or regulating the electric motor, virtual intermediate gears or continuously variable operation can be realized by varying the speed of the electric motor, allowing the driver to transition smoothly between the gear ratios. No torque sensor is required to control and / or regulate the electric motor, as the electric motor can determine the required support torque on the planetary gear set and thus indirectly the muscle drive torque.

[0016] A shaft is not exclusively understood as a cylindrical, rotatably mounted machine element for transmitting torque. Rather, it also includes general connecting elements that connect individual components together, particularly connecting elements that connect multiple components in a rotationally fixed manner.

[0017] For the purposes of the invention, a manual transmission is considered to be a transmission by means of which different gears with different ratios can be realized between the bottom bracket crankshaft, which is not part of the transmission, and the transmission output shaft.

[0018] The electrical machine consists of at least a rotationally fixed stator and a rotatably mounted rotor and is designed to convert electrical energy into mechanical energy in the form of speed and torque in motor operation, and to convert mechanical energy into electrical energy in the form of current and voltage in generator operation.

[0019] In a special embodiment, the superposition gear can have at least three, in particular exactly three, elements. In a superposition gear, two of the three elements function as input elements and the third element as the output element. The superposition gear can be designed as any gear with three shafts and two degrees of freedom for the superposition function. The superposition gear can be designed as a planetary gear set. Alternatively, the superposition gear can be designed as a harmonic drive and / or cycloidal drive. The electric machine can be coupled to the element of the superposition gear in which the smallest gear ratio is set when at least one of the other elements of the superposition gear is held stationary.

[0020] If the superposition gear is designed as a planetary gear set, the element of the superposition gear can be a sun gear of the planetary gear set and the other element of the superposition gear can be a carrier of the planetary gear set.

[0021] The electric motor can be connected to the sun gear of the planetary gear set via a shaft in a rotationally fixed manner, or can be connected in a rotationally fixed manner. The manual transmission output shaft can be connected to a ring gear of the planetary gear set in a rotationally fixed manner, and the planetary gear set carrier can be connected to a transmission output shaft of the transmission in a rotationally fixed manner, or can be connected in a rotationally fixed manner.

[0022] The transmission output shaft can pass through a plane in an area located radially below the sun gear of the planetary gear set, which plane contains the planetary gear set, i.e. the ring gear, the carrier and the sun gear of the planetary gear set.

[0023] The plane can divide a cavity of the bottom bracket shell into one area where the manual transmission is located and another area. With the aforementioned configuration of the web, the electric motor is located in the other area. In an alternative design, the transmission output shaft can pass through the plane in an area located radially above the ring gear of the planetary gear set. In this case, the electric motor is located in the area of ​​the cavity where the manual transmission is also located.

[0024] In a particular embodiment, the manual transmission can have a first planetary gear set and a first shifting element associated with the first planetary gear set. Furthermore, the manual transmission can have a second planetary gear set and a second shifting element associated with a second planetary gear set. In particular, the manual transmission can be designed to have exactly two planetary gear sets. The first shifting element and / or the second shifting element can be designed as a brake.

[0025] Furthermore, the manual transmission can have a first shaft that is operatively connected to the first planetary gear set and the second planetary gear set. Furthermore, the first shaft can be rotationally fixedly connected to a transmission housing by means of the first shifting element. The manual transmission can have a third shifting element, wherein the first shaft can be rotationally fixedly connected to the manual transmission output shaft by means of the third shifting element.

[0026] The gear housing can be part of the drive bearing housing, i.e., it can be constructed in one piece with the bottom bracket shell. Alternatively, the gear housing can be a separate housing from the bottom bracket shell, which can be inserted into a cavity in the bottom bracket shell.

[0027] Furthermore, the manual transmission can have a second shaft. The second shaft can be operatively connected to the first planetary gear set and the second planetary gear set. Furthermore, the manual transmission can have a fourth shifting element, and the second shaft can be rotationally fixedly connected to the manual transmission output shaft by means of the fourth shifting element.

[0028] The third and / or fourth shifting element can be designed as a clutch. Furthermore, the third and / or fourth shifting element can be connected upstream of a coupling region of the manual transmission output shaft with the superposition gear.

[0029] A particularly advantageous embodiment is one in which a carrier of the first planetary gear set is rotationally fixed to the bottom bracket crankshaft, a ring gear of the first planetary gear set is rotationally fixed to the first shaft, and a sun gear of the first planetary gear set is rotationally fixed to the second shaft. The carrier of the second planetary gear set is rotationally fixed to the first shaft, a ring gear of the second planetary gear set is rotationally fixed to the transmission housing by means of the second shifting element, and a sun gear of the second planetary gear set is rotationally fixed to the second shaft.

[0030] The first and / or second planetary gear set and the superposition gearing designed as a planetary gear set can be designed as a negative planetary gear set. Alternatively, it is conceivable that the first and / or second planetary gear set and / or the planetary gear set are designed as a positive planetary gear set.

[0031] A minus planetary gear set corresponds to a planetary gear set with a carrier on which the planet gears are rotatably mounted, a sun gear, and a ring gear, wherein the teeth of at least one of the planet gears mesh with the teeth of the sun gear as well as with the teeth of the ring gear, whereby the ring gear and the sun gear rotate in opposite directions when the sun gear rotates with the carrier stationary. In contrast, a plus planetary gear set differs from the minus planetary gear set in that the plus planetary gear set has inner and outer planet gears which are rotatably mounted on the carrier. The teeth of the inner planet gears mesh with the teeth of the sun gear on the one hand and with the teeth of the outer planet gears on the other. The teeth of the outer planet gears also mesh with the teeth of the ring gear.This means that when the web is stationary, the ring gear and the sun gear rotate in the same direction.

[0032] In a very special design, the manual transmission output shaft can have a fixed gear that is operatively connected to the superposition gearing. If the superposition gearing is designed as a planetary gear set, the fixed gear can mesh with the ring gear of the planetary gear set.

[0033] The manual transmission output shaft can be arranged offset, particularly in the radial direction, from the electric motor and / or a center axis of the transmission and / or the bottom bracket crankshaft. The manual transmission output shaft can run parallel to the bottom bracket crankshaft and / or a rotor shaft of the electric motor. Alternatively, it is also possible for the manual transmission output shaft to extend through the electric motor. In this case, the manual transmission output shaft is arranged coaxially with the electric motor. This design offers the advantage that the transmission can be constructed compactly in the radial direction.

[0034] The manual transmission can have at least one, in particular exactly four, spur gear sets that are operatively connected to the bottom bracket crankshaft. A spur gear set can have a fixed gear and an idler gear that mesh with each other. The idler gear of the spur gear set can be assigned to the manual transmission output shaft. The idler gear can be rotationally fixedly connected to the manual transmission output shaft by actuating a shifting element assigned to the idler gear. The fixed gear of the spur gear set can be rotationally fixedly connected to the bottom bracket crankshaft. In this embodiment, the manual transmission can not have a planetary gear set. If multiple spur gear sets are provided, each spur gear set can be designed as previously described.

[0035] The electric motor can be arranged offset, particularly radially, from a center axis of the transmission and / or the bottom bracket crankshaft. This offers the advantage that the inner diameter of the electric motor can be freely selected, since the bottom bracket bearing shaft does not have to extend through the electric motor. Furthermore, the electric motor can be arranged in an area of ​​the bottom bracket where sufficient space is available and / or which is not required for other bottom bracket components.

[0036] The electric machine can be operatively connected to the superposition gearing by means of at least one further planetary gear set and / or at least one spur gear. The provision of the further superposition gearing and / or spur gearing has the advantage that a high pre-transmission ratio can be realized between the electric machine and the traction mechanism carrier and / or an operative connection of the electric machine to the superposition gearing is achieved in a simple manner. Alternatively or additionally, at least one freewheel can be provided, which decouples the electric machine when the bottom bracket crankshaft is not being pedaled and / or which prevents the bottom bracket crankshaft from rotating. In particular, the freewheel can be arranged drive-wise between the electric machine and the transmission output shaft. Of course, other freewheel arrangements are also possible.

[0037] A bottom bracket with the bottom bracket crankshaft and the transmission according to the invention is particularly advantageous. The transmission can be operatively connected to the bottom bracket crankshaft. In particular, the carrier of the first planetary gear set can be rotationally fixedly connected to the bottom bracket crankshaft. In the alternative embodiment, in which the transmission has at least one spur gear set, the fixed gear of the spur gear set, or if multiple spur gear sets are provided, each of the fixed gears of the spur gear sets can be rotationally fixedly connected to the bottom bracket crankshaft.

[0038] The bottom bracket can have a bottom bracket shell, with the transmission located in a cavity within the bottom bracket shell. Compared to designs where the transmission is located on and / or in the rear wheel, arranging the transmission in the bottom bracket offers the advantage of a better center of gravity for the bicycle. This has a positive effect on riding comfort.

[0039] It is also possible to install the transmission, especially including the electric motor, as a modular unit in the bottom bracket. Providing the transmission as a modular unit that can only be installed in or removed from the bottom bracket as a whole offers the advantage of making it easy to install the transmission in or remove it from the bottom bracket. A further advantage of locating the transmission in the bottom bracket is that, compared to a rear-wheel drive, a high pre-gear ratio of the electric motor is possible. A bicycle with the bottom bracket or transmission integrated is particularly advantageous.

[0040] The subject matter of the invention is schematically illustrated in the figures and is described below with reference to the figures, wherein identical or equivalent elements are generally provided with the same reference numerals. Herein: Fig. 1 a schematic representation of the transmission according to the invention according to a first embodiment, Fig. 2 a schematic representation of the transmission according to the invention according to a second embodiment, Fig. 3 a table with values ​​for the stationary ratio of the planetary gear sets, Fig. 4 a switching matrix for the Fig. 1 and Fig. 2 shown gearboxes, Fig. 5 a schematic representation of the transmission according to the invention according to a third embodiment, Fig. 6 a line sketch of the Fig. 5 illustrated transmission according to the third embodiment, Fig. 7 a schematic representation of the transmission according to the invention according to a fourth embodiment, Fig. 8 a line sketch of the Fig. 7 illustrated transmission according to the fourth embodiment.

[0041] Fig. Figure 1 shows a transmission according to the first embodiment. The transmission is designed to be rotationally symmetrical to a central axis M of the transmission, wherein Fig. 1 only the upper half is shown.

[0042] The transmission comprises a manual transmission 1, which has a manual transmission output shaft 3 and is operatively connected to a bottom bracket crankshaft 2. Furthermore, the transmission comprises an electric motor 5 and a superposition gear 4, which is connected downstream of the manual transmission 1. The superposition gear 4 is designed as a planetary gear set.

[0043] The electric motor 5 is rotationally fixedly connected to a sun gear of the planetary gear set by means of a shaft 6. The manual transmission output shaft 3 is rotationally fixedly connected to a ring gear of the planetary gear set. A carrier of the planetary gear set is rotationally fixedly connected to a transmission output shaft 7.

[0044] The gearbox output shaft 7 is provided with a Fig. 1 is non-rotatably connected to a traction mechanism carrier (not shown), such as a sprocket or belt pulley. The torque provided by the transmission is transmitted via the traction mechanism carrier to a rear wheel (not shown) by means of a chain or belt.

[0045] The planetary gear set, in particular the ring gear, the carrier and the sun gear of the planetary gear set, are arranged in a plane E. The transmission output shaft 7 extends through the plane E in a region located radially below the sun gear of the planetary gear set. The plane E separates a cavity of a bottom bracket shell 21 into a region 22 in which the manual transmission 1 is arranged and another region 22. The electric machine 5 is arranged in the other region 22.

[0046] The manual transmission 1 has a first planetary gear set PS1, a second planetary gear set PS2, a first shaft 8, and a second shaft 9. Furthermore, the shifting element has a first shifting element S1, a second manual transmission S2, a third shifting element S3, and a fourth shifting element S4. The first shifting element S1 and the second shifting element S2 are designed as brakes. The third shifting element S3 and the fourth shifting element S4 are designed as clutches. Furthermore, the third shifting element S3 and the fourth shifting element S4 are combined to form a double shifting element.

[0047] The first shaft 8 is operatively connected to the first planetary gear set PS1 and the second planetary gear set PS2 and is rotationally fixedly connected to the manual transmission output shaft 3 by means of the third shifting element S3. Furthermore, the first shaft 8 is rotationally fixedly connected to a transmission housing 10 by means of the first shifting element S1. The second shaft 9 is operatively connected to the first planetary gear set PS1 and the second planetary gear set PS2 and is rotationally fixedly connected to the manual transmission output shaft 3 by means of the fourth shifting element S4.

[0048] A carrier of the first planetary gear set PS1 is rotationally fixed to the bottom bracket crankshaft 2. The sun gear of the first planetary gear set PS1 is rotationally fixed to the second shaft 9. A ring gear of the first planetary gear set PS1 is rotationally fixed to the first shaft 8.

[0049] A sun gear of the second planetary gear set PS2 is rotationally fixed to the second shaft 9, and a carrier of the second planetary gear set PS2 is rotationally fixed to the first shaft 8. A ring gear of the second planetary gear set PS2 is rotationally fixed to the transmission housing 10 by means of the second shift element S2.

[0050] The manual transmission 1 is arranged coaxially with the superposition gearing 4. In particular, the first and second planetary gear sets PS1, PS2 are arranged coaxially with the planetary gear set. Furthermore, the manual transmission and the superposition gearing are arranged coaxially with the bottom bracket crankshaft 2. The transmission output shaft 7 is also arranged coaxially with the bottom bracket crankshaft 2.

[0051] Fig. Figure 2 shows a transmission according to a second embodiment. This differs from the one shown in Fig. 1 according to the first exemplary embodiment in the arrangement of the electric machine 5 and the course of the transmission input shaft 7. In particular, the transmission input shaft 7 passes through the plane E in a region located radially above the ring gear of the planetary gear set. The electric machine 5 is arranged in the region 22.

[0052] Fig. 3 shows a table with values ​​for the stationary gear ratio of the planetary gear sets of manual transmission 1. It can be seen from the table that the first planetary gear set PS1 and the second planetary gear set PS2 have the same stationary gear ratio.

[0053] Fig. 4 shows a switching matrix for the Fig. 1 and Fig. 2. The letter “x” means that the respective switching element is closed. The Fig. 1 and Fig. The gearbox shown in Figure 2 has a total of four gears. In addition, Fig. 4 the values ​​for the gear ratio “i” between the bottom bracket crankshaft 2 and the gearbox output shaft 7 are given. In addition, Fig. 4 values ​​for the gear steps called “phi”.

[0054] The Fig. 5 and Fig. 6 show a transmission according to the third embodiment. The transmission differs from the Fig. 1 and Fig. 2 shown gearboxes in the design of the manual gearbox 1.

[0055] The manual transmission has four spur gear sets (SR). Each of the spur gear sets (SR) has a fixed gear 14 and an idler gear 15, with the spur gear sets differing in the diameter of the fixed gears and idler gears. Only one spur gear set is described below; however, the remaining spur gear sets are designed similarly.

[0056] The fixed gear 14 of the spur gear set SR is rotationally fixed to the bottom bracket crankshaft 2. The idler gear 15 of the spur gear set SR is assigned to the manual transmission output shaft 3. A rotationally fixed connection between the idler gear 15 and the manual transmission output shaft 3 can be realized by means of a switching element (not shown).

[0057] The manual transmission output shaft 3 is located radially between the electric motor 5 and the bottom bracket crankshaft 2 and / or runs parallel to the bottom bracket crankshaft 2. Furthermore, the manual transmission output shaft 3 has a fixed gear 12 that is operatively connected to the superposition gear 4. In particular, the fixed gear 12 meshes with the ring gear of the planetary gear set.

[0058] A further difference is that the electric machine 5 has a rotor shaft 16 coupled to a sun gear of another planetary gear set 13. The other planetary gear set 13 is operatively connected to a spur gear 17; in particular, the ring gear of the other planetary gear set 13 meshes with a gear 18 of the spur gear 17. Another gear 19 of the spur gear 17 meshes with the sun gear of the planetary gear set.

[0059] In addition, the transmission has a power electronics unit 20. The transmission output shaft 7 is connected in a rotationally fixed manner to a traction mechanism carrier 24.

[0060] The Fig. 7 and Fig. 8 show a transmission according to the invention according to a fourth embodiment. Fig. 7 and Fig. The gearbox shown in Figure 8 differs from the one shown in Fig. 5 and Fig.6 in that the manual transmission output shaft 3 extends through the electric machine 5. In particular, the manual transmission output shaft 3 runs coaxially with the rotor shaft 16 of the electric machine 5. A further difference is that in the transmission according to the fourth embodiment, there is no additional planetary gear set 13. Thus, the rotor shaft 16 is operatively connected to the planetary gear set, in particular to the sun gear of the planetary gear set, by means of the spur gear 17, i.e., the gear 18 and the additional gear 19.

[0061] The idler gears 15 are arranged at one end of the manual transmission output shaft 3, and the fixed gear 12, which is operatively connected to the planetary gear set, is arranged at another end of the manual transmission output shaft 3. In particular, the idler gears 15 are arranged such that, in the axial direction, the electric machine 5 is arranged between the idler gears and the fixed gear 12. Reference symbol 1 manual transmission 2 bottom bracket crankshaft 3 Manual transmission output shaft 4 superposition gears 5 electric machine 6 Wave 7 Gearbox output shaft 8 first wave 9 second wave 10 Gearbox housing 12 fixed gear 13 additional planetary gear sets 14 Fixed gear of the spur gear set 15 Idler gear of the spur gear set 16 Rotor shaft 17 spur gears 18 gear 19 additional gear 20 Power electronics 21 bottom bracket shell 22 Area 23 other area E Level M Center axis of the gearbox S1 first switching element S2 second switching element S3 third switching element S4 fourth switching element PS1 first planetary gear set PS2 second planetary gear set SR spur gear set

Claims

[1] Transmission for a bicycle, comprising a manual transmission (1) which is operatively connectable to a bottom bracket crankshaft (2) and has a manual transmission output shaft (3), and an electric machine (5), wherein the transmission has a superposition transmission (4) arranged downstream of the manual transmission (1), wherein the electric machine (5) is operatively connected or operatively connectable to an element of the superposition transmission (4) and the manual transmission output shaft (3) is operatively connected to another element of the superposition transmission (4), characterized by that the manual transmission (1) has a first planetary gear set (PS1) and a first shifting element (S1) assigned to the first planetary gear set (PS1) and / or that the manual transmission (1) has a second planetary gear set (PS2) and a second shifting element (S2) assigned to the second planetary gear set (PS2). [2] Transmission for a bicycle, with a manual transmission (1) which is operatively connectable to a bottom bracket crankshaft (2) and has a manual transmission output shaft (3), and an electric machine (5), wherein the transmission has a superposition transmission (4) arranged downstream of the manual transmission (1), wherein the electric machine (5) is operatively connected or operatively connectable to an element of the superposition transmission (4) and the manual transmission output shaft (3) is operatively connected to another element of the superposition transmission (4), characterized by that the manual transmission (1) has at least one, in particular exactly four, spur gear sets which can be operatively connected to the bottom bracket crankshaft (2) and / or that the manual transmission (1) has at least one, in particular exactly four, spur gear sets, wherein a loose gear of a spur gear set is assigned to the manual transmission output shaft (3). [3] Transmission according to claim 1 or 2, characterized by , that a. the superposition gear (4) has at least three, in particular exactly three, elements and / or that b. the electrical machine (5) is operatively connected or operatively connectable to the element of the superposition gear (4), in which the smallest gear ratio is set when at least one of the other elements of the superposition gear is held. [4] Transmission according to one of the preceding claims, characterized by that the superposition gear (4) is a planetary gear set. [5] Transmission according to claim 4, characterized by that the electric machine is connected or can be connected in a rotationally fixed manner to a sun gear of the planetary gear set by means of a shaft (6), and the manual transmission output shaft (3) is connected in a rotationally fixed manner to a ring gear of the planetary gear set, and a web of the planetary gear set is connected or can be connected in a rotationally fixed manner to a transmission output shaft (7) of the transmission. [6] Transmission according to claim 5, characterized bya plane (E) containing the planetary gear set, where a. the transmission output shaft (7) passes through the plane (E) in an area located radially below the sun gear of the planetary gear set or wherein b. the transmission output shaft (7) passes through the plane (E) in an area located radially above the ring gear of the planetary gear set. [7] Transmission according to claim 1, characterized by that the gearbox (1) has a first shaft (8), a. which is operatively connected to the first planetary gear set (PS1) and the second planetary gear set (PS2) and / or b. which can be connected in a rotationally fixed manner to a transmission housing (10) by means of the first switching element (S1) and / or that c. the manual transmission (1) has a third switching element (S3), wherein the first shaft (8) can be connected in a rotationally fixed manner to the manual transmission output shaft (3) by means of the third switching element (S3). [8] Transmission according to claim 1 or 7, characterized by that the gearbox (1) has a second shaft (9), a. which is operatively connected to the first planetary gear set (PS1) and the second planetary gear set (PS2) and / or that b. the manual transmission (1) has a fourth switching element (S4) and the second shaft (9) can be connected in a rotationally fixed manner to the manual transmission output shaft (3) by means of the fourth switching element (S4). [9] Transmission according to one of claims 1, 7 or 8, characterized by , that a web of the first planetary gear set (PS1) is rotatably connected to the bottom bracket crankshaft (2) and a ring gear of the first planetary gear set (PS1) is rotatably connected to the first shaft (8) and a sun gear of the first planetary gear set (PS2) is rotatably connected to the second shaft (9) and that a web of the second planetary gear set (PS2) is connected in a rotationally fixed manner to the first shaft (8) and a ring gear of the second planetary gear set (PS2) is rotatably connected to the transmission housing (10) by means of the second shifting element (S2) and a sun gear of the second planetary gear set (PS2) is rotatably connected to the second shaft (9). [10] Transmission according to one of claims 1 to 9, characterized by that the manual transmission output shaft (3) has a fixed gear (12) which is operatively connected to the superposition gear (4). [11] Transmission according to claim 10, characterized by , that a. the gearbox output shaft (3) is arranged offset to the electric machine (5) or that b. the manual transmission output shaft (3) extends through the electric machine (5). [12] Transmission according to one of claims 1 to 11, characterized bythat the electric machine (5) is operatively connected to the superposition gear (4) by means of at least one further planetary gear set (13) and / or at least one spur gear. [13] Bottom bracket with a bottom bracket crankshaft (3) and a transmission according to one of claims 1 to 12, characterized by that the gearbox (1) is operatively connected to the bottom bracket crankshaft (2). [14] Bicycle with a transmission according to any one of claims 1 to 12 or a bottom bracket according to claim 13.

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