Multi-stage planetary gear for a bicycle and bicycle

Abstract

A multi-stage planetary transmission for a bicycle is proposed, comprising a transmission input shaft (1) as the input and a transmission output shaft (2) as the output, and having four interconnected planetary gear sets (RS1, RS2, RS3, RS4), with four freewheel clutches (F1, F2, F3, F4) and four brakes (B1, B2, B3, B4) provided. The invention further relates to a bicycle (3) having the multi-stage transmission.

Description

[0001] The present invention relates to a multi-stage planetary transmission for a bicycle. Furthermore, the invention relates to a bicycle with the multi-stage transmission.

[0002] For example, a multi-stage planetary transmission for bicycles is known from DE 10 2020 206 299 A1. The multi-stage transmission comprises four interconnected planetary gear sets, four brakes, and four freewheel clutches to achieve 16 gears with a total gear ratio spread of approximately 260% and gear increments of approximately 6.5%.

[0003] DE 10 2023 202 060 A1 relates to a drive device for a muscle-powered vehicle, which comprises a transmission unit arranged coaxially to the crankshaft, as well as an axially parallel offset electric machine, which is mechanically connected to the output shaft via a spur gear set, and intermediate shafts which are arranged radially overlap-free to the rotatable elements of the transmission.

[0004] The present invention is based on the object of proposing an improved multi-stage transmission and a bicycle with the multi-stage transmission.

[0005] This object is achieved according to the invention by the subject matter having the features of the independent patent claims. Advantageous claimed developments emerge from the subclaims and the descriptions and drawings.

[0006] Accordingly, a multi-stage planetary transmission for a bicycle is proposed, comprising a transmission input shaft as the input and a transmission output shaft as the output, and four interconnected planetary gear sets, with four freewheel clutches and four brakes. The bicycle is preferably designed as a bicycle with an electric (auxiliary) drive, for example, as a pedelec, e-bike, cargo bike, or velomobile.

[0007] It is provided that the transmission input shaft is connected to a planetary gear carrier of a first planetary gear set, that a sun gear of the first planetary gear set is connected to a planetary gear carrier of a second planetary gear set, that a ring gear of the first planetary gear set is connectable to a ring gear of the second planetary gear set via a second one-way clutch.

[0008] It is also provided that the ring gear of the first planetary gear set is connected to a planet gear carrier of a third planetary gear set, that a sun gear of the second planetary gear set can be locked via a first brake, that the sun gear of the second planetary gear set can be connected to the transmission input shaft via a first one-way clutch, that the ring gear of the second planetary gear set can be locked via a second brake.

[0009] It is also provided that a sun gear of the third planetary gear set can be locked via a third brake, that the sun gear of the third planetary gear set can be connected via a third one-way clutch to a ring gear of the third planetary gear set and to a planet gear carrier of a fourth planetary gear set, that a sun gear of the fourth planetary gear set is connected to a transmission output shaft, that a ring gear of the fourth planetary gear set can be locked via a fourth brake and that the ring gear of the fourth planetary gear set can be connected to the transmission output shaft via a fourth one-way clutch.

[0010] In order to enable electrical assistance in addition to muscle power drive by the driver, the multi-stage transmission according to the invention is provided with at least one electric machine. The electric machine is connected to the transmission output shaft according to the invention via a gear stage. Alternative designs have a connection via several gear stages, chains, toothed belts or the like. A switching element such as a freewheel clutch or the like can also be used for this purpose. This has the advantage that when the electric motor is switched off, no drag torque occurs during pedaling and the electric motor is switched off. If the connection is via a gear stage, for example, a gear ratio can be achieved, for example to slow down.

[0011] The following is a description of the shift logic that can be implemented with the transmission using a few shift examples: To shift into first gear, the first, second, third and fourth brakes are open, with the first, second, third and fourth one-way clutches in the locking direction. To shift into second gear, the first brake is closed and the second, third and fourth brakes are open, with the first one-way clutch in the overrunning drive state and the second, third and fourth one-way clutches in the locking direction. To shift into third gear, the second brake is closed and the first, third and fourth brakes are open, with the second one-way clutch in the overrunning drive state and the first, third and fourth one-way clutches in the locking direction.

[0012] To engage a fourth gear, the first and second brakes are closed and the third and fourth brakes are opened, with the first and second one-way clutches in the overrunning drive state and the third and fourth one-way clutches in the locking direction state.

[0013] To engage a gear with the highest ratio, the first, second, third and fourth brakes are closed, with the first, second, third and fourth freewheel clutches in the overrunning drive state.

[0014] In the proposed multi-speed transmission, in a first alternative, up to three brakes can be released and one brake engaged simultaneously, or up to three brakes can be engaged and one brake released simultaneously, when changing gears to the next higher or lower gear. As a second alternative, in the proposed multi-speed transmission, a maximum of only two instead of three brakes can be released and one brake engaged simultaneously, or a maximum of only two instead of three brakes can be engaged and one brake released simultaneously, when changing gears to the next higher or lower gear.

[0015] A preferred embodiment of the invention can provide for the individual gear sets to be designed as negative planetary gear sets, resulting in a particularly space-efficient arrangement. It is also conceivable for one or more of the individual gear sets to be designed as positive planetary gear sets.

[0016] A negative planetary gear set can preferably be converted into a positive planetary gear set if the planet carrier and ring gear connections on this gear set are swapped and the amount of the stationary gear ratio is increased by 1. A negative planetary gear set has rotatably mounted planet gears on its planet carrier, which mesh with the sun gear and the ring gear of this planetary gear set, so that the ring gear rotates in the opposite direction to the sun gear rotation when the planet carrier is held stationary and the sun gear is rotating.A plus planetary gear set has inner and outer planetary gears that are rotatably mounted on its planetary gear carrier and mesh with one another, with the sun gear of this planetary gear set meshing with the inner planetary gears and the ring gear of this planetary gear set meshing with the outer planetary gears, so that the ring gear rotates in the same direction of rotation as the sun gear when the planetary gear carrier is held stationary and the sun gear is rotating.

[0017] The object underlying the invention is also achieved by a bicycle, for example a pedelec, e-bike or the like, with the multi-stage transmission described above, whereby the advantages already described and further advantages arise.

[0018] The present invention is further explained below with reference to the drawing. It shows: Fig. 1 a schematic view of a possible gear set design of a multi-stage transmission according to the invention with four planetary gear sets;

[0019] In Fig. Figure 1 illustrates a possible gear set design of a multi-stage transmission according to the invention, exemplified as a bottom bracket transmission in a coaxial design, using a bicycle 3. The bicycle 3 is designed as a pedelec.

[0020] The proposed multi-stage transmission can be used for a bicycle 3 or the like. The multi-stage transmission comprises a transmission input shaft 1 as a drive, which Fig. 1 is designed, for example, as a pedal crankshaft, and a transmission output shaft 2 as output, which can be designed, for example, as a chainring or as a chain or toothed belt wheel.

[0021] The multi-stage transmission comprises four interconnected planetary gear sets RS1, RS2, RS3, RS4, which are Fig.1 are designed, for example, as negative planetary gear sets. Furthermore, four freewheel clutches F1, F2, F3, F4 and four brakes B1, B2, B3, B4 are provided.

[0022] In detail, the bottom bracket transmission is provided with the following: the transmission input shaft 1 is connected to a planetary gear carrier PT1 of a first planetary gear set RS1, a sun gear SR1 of the first planetary gear set RS1 is connected to a planetary gear carrier PT2 of a second planetary gear set RS2, a ring gear HR1 of the first planetary gear set RS1 is connectable to a ring gear HR2 of the second planetary gear set RS2 via a second one-way clutch F2, the ring gear HR1 of the first planetary gear set RS1 is connected to a planetary gear carrier PT3 of a third planetary gear set RS3, a sun gear SR2 of the second planetary gear set RS2 is lockable via a first brake B1, the sun gear SR2 of the second planetary gear set RS2 is connectable to the transmission input shaft 1 via a first one-way clutch F1, and the ring gear HR2 of the second planetary gear set RS2 is lockable via a second brake B2.that a sun gear SR3 of the third planetary gear set RS3 can be locked via a third brake B3, that the sun gear SR3 of the third planetary gear set RS3 can be connected via a third one-way clutch F3 to a ring gear HR3 of the third planetary gear set RS3 and to a planet gear carrier PT4 of a fourth planetary gear set RS4, that a sun gear SR4 of the fourth planetary gear set RS4 is connected to the transmission output shaft 2, that a ring gear HR4 of the fourth planetary gear set RS4 can be locked via a fourth brake B4, and that the ring gear HR4 of the fourth planetary gear set RS4 can be connected to the transmission output shaft 2 via a fourth one-way clutch F4. Reference symbol 1 Gearbox input shaft or bottom bracket crankshaft 2 gearbox output shaft 3 bicycles B1 first brake B2 second brake B3 third brake B4 fourth brake F1 first freewheel clutch F2 second overrunning clutch F3 third overrunning clutch F4 fourth overrunning clutch HR1 ring gear of the first planetary gear set HR2 ring gear of the second planetary gear set HR3 ring gear of the third planetary gear set HR4 ring gear of the fourth planetary gear set PT1 planetary gear carrier of the first planetary gear set PT2 planetary gear carrier of the second planetary gear set PT3 planetary gear carrier of the third planetary gear set PT4 planetary gear carrier of the fourth planetary gear set SR1 sun gear of the first planetary gear set SR2 sun gear of the second planetary gear set SR3 sun gear of the third planetary gear set SR4 sun gear of the fourth planetary gear set RS1 first planetary gear set RS2 second planetary gear set RS3 third planetary gear set RS4 fourth planetary gear set

Claims

[1] Multi-stage planetary gear for a bicycle (3), with a gear input shaft (1) as input and a gear output shaft (2) as output and with four planetary gear sets (RS1, RS2, RS3, RS4) coupled to one another, with four freewheel clutches (F1, F2, F3, F4) and four brakes (B1, B2, B3, B4) being provided, with - the transmission input shaft (1) is connected to a planetary gear carrier (PT1) of a first planetary gear set (RS1), - a sun gear (SR1) of the first planetary gear set (RS1) is connected to a planetary gear carrier (PT2) of a second planetary gear set (RS2), - a ring gear (HR1) of the first planetary gear set (RS1) can be connected to a ring gear (HR2) of the second planetary gear set (RS2) via a second overrunning clutch (F2), - the ring gear (HR1) of the first planetary gear set (RS1) is connected to a planetary gear carrier (PT3) of a third planetary gear set (RS3), - a sun gear (SR2) of the second planetary gear set (RS2) can be locked via a first brake (B1), - the sun gear (SR2) of the second planetary gear set (RS2) can be connected to the transmission input shaft (1) via a first overrunning clutch (F1), - the ring gear (HR2) of the second planetary gear set (RS2) can be locked by a second brake (B2), - a sun gear (SR3) of the third planetary gear set (RS3) can be locked via a third brake (B3), - the sun gear (SR3) of the third planetary gear set (RS3) is connectable via a third overrunning clutch (F3) to a ring gear (HR3) of the third planetary gear set (RS3) and to a planetary gear carrier (PT4) of a fourth planetary gear set (RS4), - a sun gear (SR4) of the fourth planetary gear set (RS4) is connected to the transmission output shaft (2), - a ring gear (HR4) of the fourth planetary gear set (RS4) can be locked via a fourth brake (B4) and - the ring gear (HR4) of the fourth planetary gear set (RS4) can be connected to the transmission output shaft (2) via a fourth overrunning clutch (F4), characterized by that an electric machine for providing an electrical support power to the transmission is connected to the transmission output shaft (2) via a gear stage. [2] Multi-stage transmission according to claim 1, characterized by that the multi-stage transmission is designed as a bottom bracket transmission with coaxially arranged planetary gear sets (RS1, RS2, RS3, RS4), wherein the transmission input shaft (1) is designed as a central bottom bracket crankshaft. [3] Multi-stage transmission according to claim 1 or 2, characterized by that one or more of the planetary gear sets (RS1, RS2, RS3, RS4) are each designed as a minus planetary gear set. [4] Multi-stage transmission according to claim 1 or 2, characterized bythat one or more of the planetary gear sets (RS1, RS2, RS3, RS4) are each designed as plus planetary gear sets. [5] Bicycle (3) with a multi-stage transmission according to one of the preceding claims.

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