Pedally propelled vehicle drive system

Abstract

1. A pedally propelled vehicle drive system (1) comprising; - a crankshaft (3), - a gear system (10) with multiple selectable gear ratios, wherein the gear system has a gear input shaft (10a) and a gear output shaft (10b), and is configured to provide an output torque in an output torque direction on the gear output shaft (10b) when an in input torque in an input torque direction is present on the gear input shaft (10a), - an motor system (20) arranged concentric about the crankshaft (3).

Description

PEDALLY PROPELLED VEHICLE DRIVE SYSTEMTECHNICAL FIELD

[0001] The present invention relates to a drive system for pedally propelled vehicles, and more specifically hybrid drive systems comprising a motor system where energy transmitted to the wheels can be delivered by a rider, by the motor system, or a combination of the two.BACKGROUND

[0002] A number of different so-called pedelecs have been developed over the last decades, where some of them have motor systems in either the front or the back wheel. More and more pedelecs now have an motor system close to the crankshaft, due to advantages related to weight distribution and possibility for close integration with the battery and frame.

[0003] However, a number of issues still remain to be solved, with present crank drives. One of them is the need for reduction in the size of the drive in the area of the crank. Prior art integrated drive lines with motors and gears have require a large housing arranged in the crank region.

[0004] Only a few crank systems with integrated motor system and multi-speed gear have been disclosed. Most of them suffer from heavy weight and low performance, which makes them applicable only for a limited number of pedally propelled vehicle applications.

[0005] US2015080163 Al discloses transmission comprising: a first driving source configured to provide a rotational force and having a first input shaft; a second driving source configured to provide the rotational force and having a second input shaft; a planetary gear unit including a sun gear, a planetary gear and a ring gear, two of the sun gear, the planetary gear and the ring gear being connected to each of the first input shaft and the second input shaft, and the remaining one being connected to an output shaft; a first one-way clutch disposed between the first driving source and the planetary gear unit; and a second one-way clutch disposed between the second driving source and the planetary gear unit, wherein the first direction and the second direction are set such that the output shaft of the planetary gear unit is rotated in the same direction.

[0006] US2018370591A1 discloses a system for assisting a user in moving a device relative to a structure comprises a magnetorheological MR fluid actuator unit including at least one torque source and at least one MR fluid clutch apparatus having an input coupled to the at least one torque source to receive torque from the at least one torque source, theMR fluid clutch apparatus controllable to transmit a variable amount of assistance force via an output thereof.

[0007] WO2042428639A1 and W02020430841 disclose multi-speed gear systems for a pedally propelled vehicle.

[0008] WO2024425972A1 discloses an integrated crank drive system for a pedally propelled vehicle.

[0009] W02020130842 and WO2022240294 discloses gear system with radially stacked clutches.

[0010] One of the challenges with present days electric mid-drives with internal gears is that the space available in the crank area is very limited. Further, since the vehicle is pedally propelled the weight of the drive should be reduced.SHORT SUMMARY

[0011] The present invention as claimed solves a number of the problems associated with present crank drives.

[0012] In some embodiments the invention is a compact, distributed, pedally propelled drive train system comprising both the crank shaft, an motor system and an internal multispeed gear.

[0013] In some embodiments the weight and / or size is considerably for the vehicles in question. The weight is of great importance for the driving experience and energy consumption. Further, the price may be reduced due to lower material and manufacturing costs.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Fig. 1 illustrates in a simplified drawing an embodiment of the pedally propelled vehicle drive system 1 with a gear system 10 and a motor system 20 arranged concentric about the crankshaft 3 and the motor output torque passes through the gear system.

[0015] Fig. 2 illustrates in a simplified drawing an embodiment of the pedally propelled vehicle drive system 1, similar to the embodiment in Fig. 1, with the exception that the drive shaft 51 is hollow and the and the drive shaft 51 and the drive wheel 52 are arranged concentrically with regards to the crank shaft 3.

[0016] Fig. 3. illustrates in a simplified drawing an embodiment of the pedally propelled vehicle drive system 1 with a gear system 10 and a motor system 20 arranged concentricabout the crankshaft 3, wherein the motor output torque is driving the drive shaft 51 without an intermediate gear system.

[0017] Fig. 4 illustrates in a simplified drawing an embodiment of the pedally propelled vehicle drive system 1 with a gear system 10 and a motor system 20 arranged concentric about the crankshaft 3, wherein the motor output torque is driving the drive shaft 51 without an intermediate gear system.

[0018] Fig. 5 illustrates in a simplified drawing an embodiment of the pedally propelled vehicle drive system 1 with a gear system 10 and a motor system 20 arranged concentric about the crankshaft 3, wherein the motor output torque is driving the drive shaft 51 without an intermediate gear system.

[0019] Fig. 6 illustrates in a simplified drawing an embodiment of the pedally propelled vehicle drive system 1 with a gear system 10 and a motor system 20 arranged concentric about the crankshaft 3, wherein the motor output torque is driving the drive shaft 51 without an intermediate gear system through a reduction gear.

[0020] Fig. 7a and 7b illustrate in simplified drawings, details of the motor system 20 that may be used in combination with the embodiments in this document.

[0021] Fig. 8 illustrates in a simplified schematic drawing a side view of the the pedally propelled vehicle drive system 1 that may be an implementation of the embodiment seen in Fig. 6. Since the Figures 1 to 6 are flattened, this view illustrates better how the main elements can be organized to reduce space requirements. A guide wheel 54 for the drive transfer element 53 is here arranged rotating about the crank axle 3.EMBODIMENTS OF THE INVENTION

[0022] In the following description, various examples and embodiments of the invention are set forth in order to provide the skilled person with a more thorough understanding of the invention. The specific details described in the context of the various embodiments and with reference to the attached drawings are not intended to be construed as limitations. Rather, the scope of the invention is defined in the appended claims.

[0023] The embodiments described below are numbered. In addition, dependent embodiments defined in relation to the numbered embodiments are described. Unless otherwise specified, any embodiment that can be combined with one or more numbered embodiments may also be combined directly with any of the dependent embodiments of the numbered embodiments referred to.

[0024] In an independent embodiment ED1-01, the invention is a pedally propelled vehicle drive system 1 comprising;- a crankshaft 3,- a gear system 10 with multiple selectable gear ratios, wherein the gear system has a gear input shaft 10a and a gear output shaft 10b, and is configured to provide an output torque in an output torque direction on the gear output shaft 10b when an in input torque in an input torque direction is present on the gear input shaft 10a,- an motor system 20 arranged concentric about the crankshaft 3.

[0025] ED1-02: The pedally propelled vehicle drive system 1 of ED1-01, wherein the crankshaft 3 is configured to drive the gear input shaft 10a in the input torque direction.

[0026] ED1-03: The pedally propelled vehicle drive system 1 of any of ED1-01 to ED1-02, comprising first and second gear input wheels 41, 42, wherein the first gear input wheel 41 is arranged concentric about the crankshaft 3, the second gear input wheel 42 is arranged concentric to the gear input shaft 10a and the first gear input wheel 41 is configured to drive the second gear input wheel 42.

[0027] ED1-04: The pedally propelled vehicle drive system 1 of any of ED1-01 to ED1-03, comprising a pedal one-way clutch 31 allowing the crankshaft to drive the gear input shaft in the input torque direction and freewheel in the other direction.

[0028] ED1-05: The pedally propelled vehicle drive system 1 of ED1-04, wherein the pedal one-way clutch 31 is arranged between the crankshaft 3 and the first gear input wheel 41.

[0029] ED2-01: The pedally propelled vehicle drive system 1 of any of ED1-01 to ED1-05, wherein the motor system 20 comprises a motor output shaft 20a arranged coaxially about the crankshaft 3.

[0030] ED2-02: The pedally propelled vehicle drive system 1 of ED2-01, comprising a motor one-way clutch 21.

[0031] ED2-03: The pedally propelled vehicle drive system 1 ED2-02, wherein the motor one-way clutch 21 is connected to the motor output shaft 20a.

[0032] ED3-01: The pedally propelled vehicle drive system 1 of any of ED1-01 to ED2-03, comprising a drive wheel 52, driven by the gear output shaft 10b.

[0033] ED3-02: The pedally propelled vehicle drive system 1 of ED3-01, wherein the drive wheel 52 is a chain wheel or a belt pulley configured to hold and drive a chain or a belt, respectively.

[0034] ED3-03: The pedally propelled vehicle drive system 1 of ED3-01 or ED3-02, comprising a drive shaft 51, configured to drive the drive wheel 52.

[0035] ED3-04: The pedally propelled vehicle drive system 1 of any of ED3-01 to ED3-03, wherein the drive shaft 51 is coaxially integrated with the gear output shaft 10a.

[0036] ED3-05: The pedally propelled vehicle drive system 1 of any of ED3-01 to ED3-03, wherein the gear output shaft 10 and the drive shaft 51 are non-coaxial.

[0037] ED3-06: The pedally propelled vehicle drive system 1 of ED3-01 to ED3-05, wherein the drive shaft 51 is hollow and concentrically arranged about the crank shaft 3.

[0038] ED4-01: The pedally propelled vehicle drive system 1 any of ED1-01 to ED3-06, comprising a gear output wheel 61 arranged concentrically fixed to the gear output shaft 10b.

[0039] ED4-02: The pedally propelled vehicle drive system 1 of ED4-01, comprising a first output intermediate wheel 62 arranged concentrically fixed to drive shaft 51 and driven by the gear output wheel 61.

[0040] ED5-01: The pedally propelled vehicle drive system 1 of any of ED1-1 to ED4-02, wherein both the crankshaft 10 and the motor system 20 are arranged to provide torques to the gear input shaft 10a in the input torque direction.

[0041] ED5-02: The pedally propelled vehicle drive system 1 of ED5-01, wherein the motor one-way clutch 21 is configured to allow the motor system 20 to drive the gear output shaft 10a in one direction and freewheel in the other direction.

[0042] ED5-03: The pedally propelled vehicle drive system 1 ED5-02, wherein the motor one-way clutch 21 is arranged between the motor output shaft 20a and the first gear input wheel 41.

[0043] ED6-01. The pedally propelled vehicle drive system 1 of any of ED1-1 to ED4-02, wherein the motor system 20 is arranged to drive the drive shaft 51 in a first direction with a fixed gear ratio.

[0044] ED6-02: The pedally propelled vehicle drive system 1 of ED6-01, wherein the motor one-way clutch 21 is configured to allow the motor system 20 to drive the drive shaft 51 in the first direction and freewheel in a second direction, opposite the first direction.

[0045] ED6-03: The pedally propelled vehicle drive system 1 of ED6-01, wherein the motor system 20 is configured to operate in a regenerative mode and the drive shaft 51 is configured to rotate in a second direction opposite the first direction and to drive the motor system 20 in the regenerative mode when rotating in the second direction.

[0046] ED6-04: The pedally propelled vehicle drive system 1 of ED6-03, wherein the drive shaft 51 is rotationally fixed to the motor output shaft 20a in both the first and second direction.

[0047] With the fixed transmission, the motor system 20 is always driven by the drive shaft 51 in the second direction. Regeneration and counter-torque may be controlled by the motor controller, e.g. as a function of brake sensors configured to detect desired braking force.

[0048] ED6-05: The pedally propelled vehicle drive system 1 of ED6-03, comprising a controllable clutch arranged between the drive shaft 51 and the motor output shaft 20a.

[0049] The controllable clutch may e.g., be controlled by a control system to allow clutch engagement when the motor system 20 drives the drive shaft 51 in the first direction and to allow regeneration by clutch engagement when the drive shaft operates in the second direction and the regenerated energy is not needed.

[0050] ED6-03: The pedally propelled vehicle drive system 1 of ED6-01 or ED6-02, wherein the motor output shaft 20a and the drive shaft 51 are coaxial, and the motor oneway clutch 21 is fixed to the motor output shaft 20a and the drive shaft 51.

[0051] ED7-01: The pedally propelled vehicle drive system 1 of any of ED1-1 to ED6-03, comprising a motor output wheel 69 coaxially fixed to motor output shaft 20a.

[0052] ED7-02: The pedally propelled vehicle drive system 1 of any of ED1-1 to ED6-03, comprising a reduction gear arranged between the motor output shaft 20a and the drive shaft 51.

[0053] ED7-03: The pedally propelled vehicle drive system 1 of ED7-02, wherein the reduction gear comprises any of gear, pulley, belt and chain.

[0054] ED7-04: The pedally propelled vehicle drive system 1 of ED7-01 or ED7-02, wherein the reduction gear comprises the motor one-way clutch 21.

[0055] ED7-05: The pedally propelled vehicle drive system 1 of any of ED7-01 to ED7-03, wherein the reduction gear comprises selectable gear ratios.

[0056] ED8-01: The pedally propelled vehicle drive system 1 of any of ED1-1 to ED7-05, comprising a second output intermediate gear 63, arranged coaxially about the drive shaft 51.

[0057] ED8-02: The pedally propelled vehicle drive system 1 of ED8-01 wherein the second output intermediate gear 63 is driven by the motor output shaft 20a.

[0058] ED8-03: The pedally propelled vehicle drive system 1 of ED8-01 or ED8-02, wherein the motor output wheel 69 is configured to drive the drive second output intermediate gear 63 directly or indirectly.

[0059] ED8-04: The pedally propelled vehicle drive system 1 of any of ED8-01 to ED8-03, wherein the reduction gear is arranged between the motor output wheel 69 and the second output intermediate gear 63.

[0060] ED9-01: The pedally propelled vehicle drive system 1 of any of ED1-1 to ED7-05, wherein the reduction gear comprises first and second reduction members 64, 65.

[0061] ED9-02: The pedally propelled vehicle drive system 1 of ED9-01, wherein the first reduction members 64 meshes with the gear output wheel 61 and the second reduction member 65 meshes with the motor output wheel 69.

[0062] ED9-03: The pedally propelled vehicle drive system 1 of ED9-01 or ED9-02, wherein the first and second reduction members 64, 65 are arranged coaxially.

[0063] ED9-04: The pedally propelled vehicle drive system 1 of any of ED9-01 to ED9-03, wherein the one-way clutch is arranged between the first and second reduction members 64, 65.

[0064] ED10-01: The pedally propelled vehicle drive system 1 of any of ED01 to ED9-04, wherein the motor system 20 comprises a reduction gear 220 and an electric motor 210 connected to the reduction gear.

[0065] ED10-02: The pedally propelled vehicle drive system 1 of ED10-1, wherein the reduction gear 220 is a planetary gear system configured to rotate the motor output shaft 20a with a low rotational speed when the electric motor rotates in one direction and a high rotational speed when the motor operates in a second rotational direction .

[0066] ED10-03: The pedally propelled vehicle drive system 1 of ED10-2, wherein the reduction gear 220 comprises a first pawl 241 configured to selectably fixing a ring gear 241 and a carrier 224 to the motor output shaft 20a and a second pawl 242 selectably fixing the ring gear 241 and the carrier 224 to the housing of the motor system 20.

[0067] ED11-01: The pedally propelled vehicle drive system 1 of any of ED1-01 to ED10- 03, wherein the gear system 10 comprises;- first and second interconnected epicyclical gear sections, comprising first and second radially stacked planet carrier elements, respectively,- first and second shift mechanisms, each comprising radially stacked clutches configured to disengage and engage the first and second planet carrier elements, respectively to change the gear ratio of the gear system 10.

[0068] ED11-02: The pedally propelled vehicle drive system 1 of ED11-01, wherein the radially stacked clutches are configured to allow the gear input and output shafts 10a, 10b to freewheel in one direction.

[0069] An example of a gear system with radially stacked clutches can be found in International publication W02020130841A1, Fig. 1, 4a, 4b, 4c, 5a, 5b, 5c and corresponding description, which is hereby incorporated by reference.

[0070] In the following sections, specific embodiments will be presented with reference to the figures provided.

[0071] In the embodiment illustrated in Fig. 1, the pedally propelled vehicle drive system 1 comprises a gear system 10 and a motor system 20 arranged concentric about the crankshaft 3. Both the crank shaft 3 and electric motor system 20 can provide input torque to the gear input shaft 10a of the gear system via one-way clutches 31, 21, respectively. The output torque from the gear system 10 on the gear output shaft 10b is transferred to the drive shaft 51 integrated with the drive wheel 52, driving a drive transfer element 53, such as e.g., a belt or a chain. A gear output wheel 61 fixed concentrically to the gear output shaft 10b, meshes with a first output intermediate gear 62, concentrically fixed to the drive shaft 51. The drive shaft 51 is here arranged non -concentrically and in parallel with reference to the crankshaft 3. It is also non-concentrically arranged with regards to the gear output shaft 10b.

[0072] In the embodiment illustrated in Fig. 2, the pedally propelled vehicle drive system 1 is similar to the embodiment in Fig. 1, with the exception that the drive shaft 51 is hollow and the and the drive shaft 51 and the drive wheel 52 are arranged concentrically with regards to the crank shaft 3.

[0073] In the embodiment the pedally propelled vehicle drive system 1 illustrated in Fig. 3, the crank shaft 3 and can provide input torque to the gear input shaft 10a of the gear system via one-way clutch 31. The output torque from the gear system 10 on the gear output shaft 10b is transferred to the drive shaft 51 integrated with the drive wheel 52,driving a drive transfer element 53, such as e.g., a belt or a chain. A gear output wheel 61 fixed concentrically to the gear output shaft 10b, meshes with a first output intermediate gear 62, concentrically fixed to the drive shaft 51. The drive shaft 51 is hollow and the and the drive shaft 51 and the drive wheel 52 are arranged concentrically with regards to the crank shaft 3. Further, the motor system 20 is arranged concentrically about the crank shaft 3, and a hollow motor output shaft 20a transfers motor torque directly to the drive shaft 51 via the motor one-way clutch 21.

[0074] In the embodiment the pedally propelled vehicle drive system 1 illustrated in Fig.4, the crank shaft 3 can provide input torque to the gear input shaft 10a of the gear system via one-way clutch 31. The output torque from the gear system 10 on the gear output shaft 10b, integrated with the drive shaft 51 and coaxially fixed to the drive wheel 52, is driving a drive transfer element 53, such as e.g., a belt or a chain. The motor system 20 is arranged concentrically about the crank shaft 3, and a hollow motor output shaft 20a transfers motor torque to the drive shaft 51 via a motor output wheel 69 concentrically fixed to the motor output shaft 20a. The motor output wheel 69 drives a second output intermediate gear 63 arranged concentrically about the drive shaft 51. The motor one-way clutch 21 arranged between the second output intermediate gear 63 and the drive shaft 51, allows the motor system 20 to transfer torque to the drive shaft in one direction and freewheel in the other direction. An intermediate gear input wheel 43 arranged between the first and second gear input wheels 41, 42, ensures that the drive wheel 52 rotates in the same direction as the crank axle 3.

[0075] In the embodiment the pedally propelled vehicle drive system 1 illustrated in Fig.5, the crank shaft 3 can provide input torque to the gear input shaft 10a of the gear system via one-way clutch 31. The output torque from the gear system 10 on the gear output shaft 10b is transferred to the drive shaft 51 integrated with the drive wheel 52, driving a drive transfer element 53, such as e.g., a belt or a chain. A gear output wheel 61 fixed concentrically to the gear output shaft 10b, meshes with a first output intermediate gear 62, concentrically fixed to the drive shaft 51. The drive shaft 51 is here arranged non- concentrically and in parallel with reference to the crankshaft 3. The motor system 20 is arranged concentrically about the crank shaft 3, and a hollow motor output shaft 20a transfers motor torque to the drive shaft 51 via a motor output wheel 69 concentrically fixed to the motor output shaft 20a. The motor output wheel 69 drives a second output intermediate gear 63 arranged concentrically about the drive shaft 51. The motor one-way clutch 21 arranged between the second output intermediate gear 63 and the drive shaft 51, allows the motor system 20 to transfer torque to the drive shaft in one direction andfreewheel in the other direction. The motor output wheel 69 may be connected with the intermediate gear 63 via e.g. a chain, belt or additional gears.

[0076] In the embodiment the pedally propelled vehicle drive system 1 illustrated in Fig. 6, the crank shaft 3 can provide input torque to the gear input shaft 10a of the gear system via one-way clutch 31. The output torque from the gear system 10 on the gear output shaft 10b is transferred to the drive shaft 51 integrated with the drive wheel 52, driving a drive transfer element 53, such as e.g., a belt or a chain. A gear output wheel 61 fixed concentrically to the gear output shaft 10b, meshes with a first output intermediate gear 62, concentrically fixed to the drive shaft 51. The motor system 20 is arranged concentrically about the crank shaft 3, and a hollow motor output shaft 20a transfers motor torque to the drive shaft 51 via a motor output wheel 69 concentrically fixed to the motor output shaft 20a. A reduction gear comprising a third output intermediate gear 64 and a fourth output intermediate gear 65 is arranged between the motor output wheel 69 and the drive shaft 51. The third output intermediate gear 64 meshes with the motor output wheel 69 and the fourth intermediate gear 65 meshes with the gear output wheel 61. Further, the fourth output intermediate gear 65 is configured to be driven by the third output intermediate gear 64, at least in one rotational direction. Since the fourth output intermediate gear 65 has a smaller radius than the third output intermediate gear 64, the speed reduction is achieved. A motor one-way clutch 21 may be arranged between the third output intermediate gear 64 and the and the fourth output intermediate gear 65, allowing the motor system 20 to transfer torque to the drive shaft in one direction and freewheel in the other direction. Optionally the motor one-way clutch 21 may be arranged between the motor output shaft 20a and the motor output wheel 69.

[0077] Optionally, in Fig. 3, 4, 5 and 6, the motor system 20 can be driven in regenerative mode. The motor one-way clutch 21 may then be replaced by a fixed coupling or a controllable clutch.

[0078] In an embodiment illustrated in Fig. 7a, details of the motor system 20 that may be used in combination with the embodiments above are presented. In this embodiment, the motor system 20 comprises an electric motor 210 comprising stator and rotor windings 211, 212. A hollow electric motor shaft 215 is arranged in the center of the motor, fixed to the rotor windings.

[0079] Further, the motor system 20 comprises a reduction gear 220. Here the reduction gear is a planetary gearing, comprising a sun gear 221 fixed to the perimeter of the electric motor shaft 215, planet gears 222, a ring gear 223 fixed to the motor housing and a planet carrier 224. The planet carrier 224 is fixed to the motor output shaft 20a. Both themotor output shaft 20a and the electric motor shaft 215 are arranged coaxially supported by bearings about a motor intermediate shaft 230 running through the motor system 20.

[0080] Optionally, the planetary gearing may have two selectable gear ratios, wherein the highest gear ratio is achieved by the configuration given above in Fig. 7a where the ring gear is fixed and the planet carrier is connected to the motor output shaft 20a, and a lower gear ratio is achieved by rotating the electric motor shaft 215 in the opposite direction, fixing the carrier 224 position and connecting the ring gear 223 to the motor output shaft 20a. Switching between the higher and lower gear ratios may allow the electric motor to run more efficiently over a broader rpm range. In Fig. 7b, an implementation is shown where a first pawl 241 selectably fixes the ring gear 241 and the carrier 224 to the motor output shaft 20a, and a second pawl 242 selectably fixing the ring gear 241 and the carrier 224 to the housing of the motor system 20.

[0081] The intermediate shaft 230 is again arranged supported by bearings about the crank shaft 3. Optionally, the motor output shaft 20a and the electric motor shaft 215 are arranged coaxially supported by bearings about the crank shaft 3 without the motor intermediate shaft 230. Optionally, other types of reduction gears could be used between the electric motor shaft 215 and the motor output shaft 20a.

[0082] In the exemplary embodiments, various features and details are shown in combination. The fact that several features are described with respect to a particular example should not be construed as implying that those features by necessity have to be included together in all embodiments of the invention. Conversely, features that are described with reference to different embodiments should not be construed as mutually exclusive. As those with skill in the art will readily understand, embodiments that incorporate any subset of features described herein and that are not expressly interdependent have been contemplated by the inventor and are part of the intended disclosure. However, explicit description of all such embodiments would not contribute to the understanding of the principles of the invention, and consequently some permutations of features have been omitted for the sake of simplicity or brevity.

Claims

CLAIMS1. A pedally propelled vehicle drive system (1) comprising;- a crankshaft (3),- a gear system (10) with multiple selectable gear ratios, wherein the gear system has a gear input shaft (10a) and a gear output shaft (10b), and is configured to provide an output torque in an output torque direction on the gear output shaft (10b) when an in input torque in an input torque direction is present on the gear input shaft (10a),- an motor system (20) arranged concentric about the crankshaft (3).

2. The pedally propelled vehicle drive system 1 of claim 1, wherein the motor system (20) comprises a motor output shaft (20a) arranged coaxially about the crankshaft (3).

3. The pedally propelled vehicle drive system 1 of claim 1 or 2, wherein both the crankshaft (10) and the motor system (20) are arranged to provide torques to the gear input shaft (10a) in the input torque direction.

4. The pedally propelled vehicle drive system 1 of any of claims 1 to 3, comprising a drive wheel (52) and a drive shaft (51) configured to drive the drive wheel (52).

5. The pedally propelled vehicle drive system (1) of claim 4, wherein the motor system (20) is arranged to drive the drive shaft (51) with a fixed gear ratio in a first direction.

6. The pedally propelled vehicle drive system (1) of claim 5, wherein the motor output shaft (20a) and the drive shaft (51) are coaxial, and a motor one-way clutch (21) is fixed to the motor output shaft (20a) and the drive shaft (51).

7. The pedally propelled vehicle drive system (1) of any of claim 4 to 6, comprising a reduction gear arranged between the motor output shaft 20a and the drive shaft 51.

8. The pedally propelled vehicle drive system (1) of claim 7, wherein the reduction gear comprises the motor one-way clutch 21.

9. The pedally propelled vehicle drive system (1) of any claim 4 to 8, comprising a second output intermediate gear 63 driven by the motor output shaft (20a), arranged coaxially about the drive shaft (51).

10. The pedally propelled vehicle drive system (1) of any of claim 7 to 9, wherein the reduction gear comprises first and second reduction members 64, 65 and the first reduction members 64 meshes with the gear output wheel 61 and the second reduction member 65 meshes with the motor output wheel 69.

11. The pedally propelled vehicle drive system (1) of any claims 5 to 10, wherein the motor system 20 is configured to operate in a regenerative mode and the drive shaft 51 is configured to rotate in a second direction opposite the first direction and to drive the motor system 20 in the regenerative mode when rotating in the second direction.

12. The pedally propelled vehicle drive system 1 of any of the claims above, wherein the gear system 10 comprises;- first and second interconnected epicyclical gear sections, comprising first and second radially stacked planet carrier elements, respectively,- first and second shift mechanisms, each comprising radially stacked clutches configured to disengage and engage the first and second planet carrier elements, respectively to change the gear ratio of the gear system 10.

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