Pedal propulsion vehicle transmission system

Abstract

A pedal propulsion vehicle drivetrain (1), comprising a housing (2), comprising:-a crankshaft (3); an internal multi-speed gear (4) having an input shaft (4a) and an output shaft (4b) which are coaxial; an electric motor (5) having an output shaft (5a), in which the crankshaft, the input and output shafts of the internal multi-speed gear and the output shaft of the electric motor are arranged in parallel, in which both the crankshaft and the electric motor are arranged to drive the input shaft of the internal multi-speed gear in the same direction of rotation.

Description

[0001] This application is a divisional application of the Chinese patent application with the application number 202080087448.5 and the title "Transmission System for Pedal-Powered Vehicles" (based on the international patent application with the international filing date of December 16, 2020 and the international application number PCT / NO2020 / 050317, which entered the Chinese national phase on June 16, 2022). Technical Field

[0002] The present invention relates to a transmission system for pedal-powered vehicles, and more particularly to a hybrid transmission system including an electric motor, wherein the energy transmitted to the wheels can be delivered by the rider, the electric motor, or a combination of both. Background Art

[0003] In the past few decades, many different so-called assisted bicycles have been developed, some of which have electric motors on the front or rear wheels. Due to the advantages related to weight distribution and the ability to be closely integrated with the battery and the frame, more and more assisted bicycles now have an electric motor near the crankshaft.

[0004] However, there are still many problems to be solved with the current crank drive. One of them is the need for long-term reliability and reduced maintenance costs.

[0005] Only a few crank systems with integrated electric motors and multi-speed gears have been disclosed. Most of them are heavy and have low performance, making them suitable only for a small number of pedal-powered vehicle applications.

[0006] US5836414A discloses a human-powered assistive power device equipped with a differential gear mechanism, which preferably includes a pedal-driven bevel gear, a motor-driven bevel gear, and a pair of corresponding small bevel gears for driving the rotating output members.

[0007] US2017217538A1 discloses a controller that can be mounted on a bicycle, the controller including a first transmission having at least two speed change levels and configured to change the ratio of the rotation of the wheel to the rotation of the crank; a motor for providing assistance to the human power input to the crank; and a second transmission configured to transmit the rotational force from the motor to the power transmission path extending from the crank to the wheel without changing the ratio of the rotation of the wheel to the rotation of the crank.

[0008] EP3012181A1 discloses a mid-mounted motor transmission system for an electric bicycle, which includes a left housing (1), a right housing (2), a motor assembly (3), a gear reduction device (4), a torque sensor (5), a central shaft (7), a controller (8), and a crankset (9), and also includes a planetary gear speed increasing device (6).

[0009] US2015080163A1 discloses a transmission, which includes: a first drive source configured to provide a rotational force and having a first input shaft; a second drive source configured to provide a rotational force and having a second input shaft; a planetary gear unit including a sun gear, planetary gears, and a gear ring, wherein two of the sun gear, planetary gears, and gear ring are respectively connected to the first input shaft and the second input shaft, and the remaining one is connected to the output shaft; a first one-way clutch disposed between the first drive source and the planetary gear unit; and a second one-way clutch disposed between the second drive source and the planetary gear unit, wherein a first direction and a second direction are set such that the output shaft of the planetary gear unit rotates in the same direction.

[0010] US2018370591A1 discloses a system for assisting a user to move a device relative to a structure, the system including a magnetorheological (MR) fluid actuator unit including at least one torque source and at least one MR fluid clutch device having an input coupled to the at least one torque source to receive torque from the at least one torque source, the MR fluid clutch device being controllable to transmit a variable amount of assisting force via its output.

[0011] WO2012128639A1 and WO2020130841 disclose multi-speed gear systems for pedal-propelled vehicles. Summary of the Invention

[0012] The claimed invention solves many problems associated with current crank drives.

[0013] In some embodiments, the invention is a compact, integrated pedal propulsion transmission system including a crankshaft, a motor, and an internal multi-speed gear.

[0014] In some embodiments, the torque is limited. By reducing the peak torque from the crankshaft to the drive components, the transmission system components can be made smaller and lighter. For the vehicles discussed, weight is very important for the driving experience and energy consumption. In addition, the price may be reduced. Brief Description of the Drawings

[0015] Figure 1 A vehicle transmission system according to an embodiment of the invention is shown in a schematic side view.

[0016] Figure 2 Shown in a schematic top view is Figure 1 the same embodiment. Note that the figure has been flattened to better show the various components.

[0017] Figure 3 An embodiment of a torque limiter is shown in a detailed schematic view.

[0018] Figure 4 Shows an embodiment of a crankshaft wheel (6) configured to form an element of a torque limiter. The spur gear for meshing with the input shaft wheel (7) shown in Figure 2 is not shown, but can be arranged on the outer edge of the wheel.

[0019] Figure 5 and Figure 6 show an embodiment of a vehicle transmission system in opposite side views. Detailed Description

[0020] In the following description, various examples and embodiments of the present invention are set forth in order to provide a more thorough understanding of the present invention to those skilled in the art. The specific details described in the context of the various embodiments and with reference to the accompanying drawings are not intended to be construed as limiting.

[0021] The embodiments described below are numbered. In addition, dependent embodiments defined with respect to the numbered embodiments are described. Any embodiment that can be combined with one or more of the numbered embodiments can also be directly combined with any one of the dependent embodiments of the numbered embodiments mentioned, unless otherwise stated.

[0022] In a first embodiment EM1, the present invention is a pedal - propelled vehicle transmission system (1), such as shown in Figure 1 and Figure 2 . The transmission system includes a housing (2) and comprises:

[0023] - a crankshaft (3);

[0024] - an internal gear (4) having coaxial input shaft (4a) and output shaft (4b);

[0025] - an electric motor (5) having an output shaft (5a),

[0026] wherein the crankshaft, the input and output shafts of the internal gear, and the output shaft of the electric motor are arranged in parallel.

[0027] The internal gear (4) is a multi - speed gear system.

[0028] The pedal arms (3a, 3b) driving the crankshaft are as shown in Figure 2 .

[0029] EM2. The pedal - propelled vehicle transmission system according to EM1, wherein both the crankshaft and the electric motor are arranged to drive the input shaft of the internal gear in the same direction of rotation.

[0030] EM3. The pedal - propelled vehicle transmission system according to EM2, comprising a crankshaft wheel (6) coaxial with the crankshaft and an input shaft wheel (7) coaxial with the input shaft of the internal gear, wherein the crankshaft wheel is configured to drive the input shaft wheel.

[0031] EM4. The pedal - propelled vehicle transmission system according to EM3, wherein the crankshaft wheel and the input shaft wheel are configured to rotate in opposite directions.

[0032] EM5. The pedal - propelled vehicle transmission system according to EM4, wherein the crankshaft wheel and the input shaft wheel are meshing spur gears.

[0033] EM6. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments, comprising a main chain sprocket (10) configured to rotate in the opposite direction with respect to the output shaft (4b).

[0034] EM7. The pedal - propelled vehicle transmission system according to embodiment 6, wherein the main chain sprocket is arranged non - coaxially with respect to the output shaft (4a).

[0035] EM8. The pedal - propelled vehicle transmission system according to embodiment 7, comprising a main sprocket axle (15) arranged parallel to the output shaft, wherein the transmission system further comprises an output shaft wheel (4c) and a main wheel (15c), wherein the output shaft wheel is arranged on the output shaft and the main wheel is arranged on the sprocket axle.

[0036] EM9. The pedal - propelled vehicle transmission system according to embodiment 8, wherein the output shaft wheel and the main wheel are meshing spur gears and rotate in opposite directions.

[0037] EM10. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments, partially comprising a main drive chain (12) that extends over the main chain sprocket and is arranged to interconnect the main chain sprocket with a rear - wheel sprocket (13) located on the rear wheel of the pedal - propelled vehicle on which the transmission system is installed.

[0038] EM11. The pedal - propelled vehicle transmission system according to EM10, wherein the housing comprises a chain tensioner (11) arranged to tension the main drive chain (12) that extends over the main chain sprocket.

[0039] EM12. The pedal - propelled vehicle transmission system according to EM11, wherein the chain tensioner comprises a first tensioner sprocket (11a) arranged coaxial with the crankshaft.

[0040] EM13. The pedal - propelled vehicle transmission system according to EM11 or EM12, wherein the chain tensioner comprises a second tensioner sprocket (11b) arranged below the crankshaft.

[0041] EM14. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments, comprising a crank sleeve (20) and a one - way clutch (21), wherein the crank sleeve is coaxially arranged outside the crankshaft, and the one - way clutch is configured to allow the crankshaft to rotate the crank sleeve in one rotational direction and the flywheel in the other rotational direction.

[0042] EM15. The pedal - propelled vehicle transmission system according to EM14, wherein the one - way clutch is arranged inside the crank sleeve.

[0043] As a first alternative to embodiments EM14 and EM15, the one - way clutch is arranged between the input shaft wheel (7) and the input shaft (4a).

[0044] EM16. The pedal - propelled vehicle transmission system according to EM14 or EM15, wherein the one - way clutch is a ramp - type clutch.

[0045] EM17. The pedal - propelled vehicle transmission system according to any one of EM14 to EM16, wherein the crankshaft wheel (6) is arranged to be rotationally fixed to the crank sleeve (20).

[0046] Overload can be a major problem associated with the transmission system of pedal - propelled vehicles. Although a rider pushing hard on the pedals may not directly cause an overload, other aspects, such as hitting the crank arms against an obstacle, can impose harmful peak torques on the transmission system. The torque limiter according to the following embodiments is instantaneous and arranged upstream of the transmission system to protect as many components as possible. In addition, it self - repairs immediately after an accident and allows continued operation when the peak torque drops below a predefined torque limit.

[0047] EM18. The pedal - propelled vehicle transmission system according to any one of embodiments EM3 to EM17, comprising a torque limiter, wherein the torque limiter is configured to rotationally fix the crankshaft wheel (6) to the crank sleeve (20) below the torque limit and rotationally release the crankshaft wheel (6) from the crank sleeve (20) above the torque limit.

[0048] EM19. The pedal - propelled vehicle transmission system according to EM18, wherein the crankshaft wheel (6) includes radially arranged first ratchet teeth (31a).

[0049] EM20. The pedal - propelled vehicle transmission system according to EM19, comprising second ratchet teeth (32a) radially fixed to the crank sleeve (20), wherein the first ratchet teeth (31a) and the second ratchet teeth face each other in the longitudinal direction of the crankshaft (3).

[0050] EM21. The pedal - propelled vehicle transmission system according to EM20, comprising a disc spring (33) configured to urge a first ratchet tooth and a second ratchet tooth (31a, 32a) against each other.

[0051] EM22. The pedal - propelled vehicle transmission system according to any one of embodiments EM18 to EM22, wherein the crankshaft wheel includes a first axial thrust surface (31b).

[0052] EM23. The pedal - propelled vehicle transmission system according to EM22, comprising a second axial thrust surface (32b) arranged to be radially fixed to the crank sleeve (20), wherein the first axial thrust surface and the second axial thrust surface (31b, 32b) face each other in the longitudinal direction of the crankshaft (3).

[0053] EM24. The pedal - propelled vehicle transmission system according to any one of embodiments EM18 to EM23, wherein the crankshaft wheel (6) includes a first radial thrust surface (31c).

[0054] EM25. The pedal - propelled vehicle transmission system according to EM24, comprising a second radial thrust surface (32c) arranged to be radially fixed to the crank sleeve (20), wherein the first radial thrust surface and the second radial thrust surface (31c, 32c) face each other in the radial direction of the crankshaft (3).

[0055] EM26. The pedal - propelled vehicle transmission system according to EM25, comprising a ratchet sleeve (32) arranged to be coaxially fixed to the crank sleeve (20), wherein the ratchet sleeve includes a second ratchet tooth (32a), a second axial thrust surface (32b) and a first radial thrust surface (32c).

[0056] EM26a. The pedal - propelled vehicle transmission system according to any one of embodiments EM18 to EM25, comprising a locking ring (39) configured to lock the disc spring in the longitudinal position of the crankshaft (3).

[0057] EM27. The pedal - propelled vehicle transmission system according to any one of embodiments EM18 to EM26a, wherein the torque limit is higher than any one of the torque values 50 Nm, 70 Nm, 100 Nm, 120 Nm, 150 Nm, 200 Nm.

[0058] EM28. The pedal - propelled vehicle transmission system according to any one of embodiments EM18 to EM27, wherein the disc spring urges the first ratchet tooth (31a) and the second ratchet tooth against each other with a force of at least any one of the force values 3000 N, 5000 N, 7000 N, 10000 N, 12000 N, 15000 N, 20000 N.

[0059] EM29. The pedal - propelled vehicle transmission system according to any one of embodiments EM14 to EM28 includes a torque sensor (36) configured to sense the torque between the crankshaft (3) and the crank sleeve (20).

[0060] EM30. The pedal - propelled vehicle transmission system according to EM29, wherein the torque sensor is a magnetic torque sensor.

[0061] As a second alternative to embodiments EM14 and EM15, a one - way clutch is arranged between the ratchet sleeve (32) and the crank sleeve (20).

[0062] EM31. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments includes a motor wheel (17) and an input wheel (18), wherein the motor wheel (17) is arranged on the output shaft (5a) of the electric motor, and the input wheel (18) is arranged on the input shaft (4a) of the internal gear.

[0063] EM32. The pedal - propelled vehicle transmission system according to EM31 includes a second drive chain (14) interconnecting the motor wheel and the input wheel.

[0064] EM33. The pedal - propelled vehicle transmission system according to any one of EM31 and EM32 includes a second one - way clutch configured to allow the input wheel (18) to rotate the input shaft in one rotational direction and the flywheel in the other rotational direction.

[0065] EM34. The pedal - propelled vehicle transmission system according to EM33, wherein the second one - way clutch is arranged in the inner radius of the input wheel (18).

[0066] EM35. The pedal - propelled vehicle transmission system according to EM33 or 34, wherein the second one - way clutch is a ramp clutch.

[0067] EM36. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments, wherein the housing is filled with oil.

[0068] EM37. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments, wherein the internal gear includes one or more planetary gear sets.

[0069] In a dependent embodiment, the motor wheel (17) is connected to the planet carrier of the planetary gear.

[0070] In a second dependent embodiment, the output shaft (5a) of the motor drives the sun gear of the planetary gear set.

[0071] EM38. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments includes a gear shifter (16) arranged to shift gears within an internal gear, for example, by rotating a shift wheel shaft within the internal gear.

[0072] EM39. The pedal - propelled vehicle transmission system according to any one of the foregoing embodiments EM32 to EM38 includes a second chain tensioner (19) configured to tension the second drive chain (14).

[0073] In a first dependent embodiment, the pedal - propelled vehicle transmission system includes a cover arranged to cover the chain tensioner and interact with the tensioner, wherein when the cover is mounted to the housing (2), the chain tensioner tensions the second drive chain, and when the cover is removed, the chain tensioner releases the second drive chain.

[0074] In a second dependent embodiment, the cover is configured to be connected to the motor wheel (17) before reaching its final position when installed.

[0075] In a third dependent embodiment, the cover includes a wheel shaft or shaft extending from the cover and configured to enter a through - hole of a rotary bearing fixed to the motor wheel (17).

[0076] In Figure 1 and Figure 2 show specific embodiments of the pedal - propelled vehicle transmission system. Figure 1 is a partially transparent schematic side view, which includes the main elements of the transmission system. Figure 2 is a partially transparent top - down cross - sectional view showing the same elements as Figure 1 The crankshaft (3) includes a first pedal arm and a second pedal arm (3a, 3b). In addition, the crankshaft (3), the internal gear (4) and its input shaft and output shaft (4a, 4b), the electric motor (5), and the electric motor output shaft (5a) are arranged in parallel. The housing (2) is configured to be mounted in the frame of the pedal - propelled vehicle. The main drive chain (12) interconnects the transmission system and the rear - wheel sprocket (13) of the vehicle's wheel so as to drive the wheel when a driving torque is applied to the main chain sprocket of the transmission system. The transmission system includes a chain tensioner (11) that includes a first tensioner sprocket (11a) arranged to rotate freely around the crank wheel shaft (3) and a second tensioner sprocket (11b) arranged on a spring - loaded link arm (11c). In the driving direction indicated by the stitching line in Figure 1 the upper part of the main drive chain (12) extends from the rear - wheel sprocket above the main chain sprocket (10) and partially around the main chain sprocket. In addition, the main drive chain extends above the first tensioner sprocket (11a) and below the second tensioner sprocket (11b) before returning to the rear - wheel sprocket.

[0077] When torque is applied to the main chain sprocket (10), the upper part of the drive chain is tensioned, while the slack in the lower part is absorbed by the chain tensioner.

[0078] The main chain sprocket (10) is arranged on a ball bearing located on the main sprocket shaft (15), which is arranged to be fixed to the housing (2). The main chain sprocket (10) is further rotationally fixed to the main wheel (15c), which is arranged inside the main chain sprocket (10) on the main sprocket shaft (15) and is coaxial with the main chain sprocket. The output shaft wheel (4c) arranged on the output shaft (4b) of the internal gear meshes with the main wheel (15), that is, these wheels are all spur gears. Therefore, the main chain sprocket (10) is directly driven by the output shaft (4b). In the current configuration, the rotational direction of the main chain sprocket is opposite to that of the output shaft.

[0079] The input shaft (4a) of the internal gear can be driven by the crankshaft (3) or the electric motor (5) or simultaneously by both.

[0080] The electric motor (5) is arranged above the crankshaft and the internal gear. The motor wheel (17) on the motor output shaft (5a) is connected to the input wheel (18), which is arranged coaxially with the input shaft (4a) and is unidirectionally rotationally connected to the input shaft through a second one-way clutch. The second drive chain (14) connects the motor wheel (17) to the input wheel (18). The second one-way clutch arranged radially between the input wheel (18) and the input shaft (4a) allows the motor to drive the input shaft (4a) rather than the input shaft driving the motor.

[0081] Similarly, the crankshaft (3) can drive the input shaft (4a) in a rotational direction that is the same as the direction in which the motor can drive the input shaft.

[0082] The crankshaft wheel (6) is unidirectionally rotationally connected to the crankshaft (3) through a one-way clutch arranged radially between the crankshaft (3) and the crankshaft wheel (6). The crankshaft wheel (6) meshes with the input shaft wheel (7), and the input shaft wheel is connected to the input shaft (4a) of the internal gear and is axially arranged inside the input wheel (18).

[0083] Figure 1 and Figure 2 The pedal-propelled vehicle transmission system of Figure 3 also includes a torque limiter shown in more detail in

[0084] The first crankshaft wheel (6) includes first ratchet teeth (31a) that are radially arranged and face corresponding second ratchet teeth (32a) that are radially arranged on a first end of a crank sleeve (20). The crank sleeve is cylindrical in shape and is arranged outside the crankshaft (3). Further, the crank sleeve is fixed to the crankshaft (3) at a second end opposite the first end.

[0085] The disc spring (31) is held in position by a locking ring (39) fixed to the crank sleeve (20), and the disc spring urges the crankshaft wheel (6) against the input shaft wheel (7), thereby ensuring that the first and second ratchet teeth of the torque limiter engage as long as the torque on the torque limiter is below the design value given by the elasticity of the disc spring. If the torque is higher than the design value, the disc spring will cause the ratchet teeth to disengage from each other to protect components after the crank drive, such as internal gears, overrunning clutches, etc.

[0086] The crankshaft wheel (6) is axially and radially supported on a ratchet sleeve (32) by a first axial thrust surface (31b) supported by a second axial thrust surface (32b) and a first radial thrust surface (31c) supported by a second radial thrust surface (32c), respectively.

[0087] The first ratchet teeth (31a), the first axial thrust surface (31b), and the first radial thrust surface (31c) of the crankshaft wheel are as Figure 4 shown.

[0088] A magnetic torque sensor (36) is arranged outside and is located between the first end and the second end of the crank sleeve (20), and the magnetic torque sensor is configured to sense the torque between the crankshaft (3) and the crank sleeve (20).

[0089] In Figure 5 and Figure 6 In a specific embodiment of a pedal - propelled vehicle transmission system shown in opposite first and second side views, it can be seen that the crankshaft (3) includes a first pedal arm and a second pedal arm (3a, 3b). Further, the crankshaft (3), the internal gear (4) and its input and output shafts (4a, 4b), the electric motor (5), and the electric motor output shaft (5a) are arranged in parallel. The housing (2) is configured to be mounted in the frame of a pedal - propelled vehicle. The main drive chain (12) interconnects the transmission system and the rear wheel sprocket of the vehicle's wheel so as to drive the wheel when a driving torque is applied to the main chain sprocket of the transmission system. The internal gear is a multi - speed gear system and can be, for example, an adaptation of the gear system disclosed in WO2020130841A1.

[0090] In Figure 5In the first side view, which can be regarded as the output drive side, we can see that the chain tensioner (11) is an integrated part of the drive system, meaning that no additional external chain tensioner is required and the work related to installation and maintenance can be reduced. In most of the prior arts, the chain tensioner is located near the rear wheel sprocket or hub or is installed as a separate tensioner in the crank area.

[0091] The chain tensioner includes a first tensioner sprocket (11a) arranged to freely rotate around the crankshaft (3), and a second tensioner sprocket (11b) arranged on a spring-loaded link arm (11c). In the driving direction indicated by the binding thread, the upper part of the main drive chain (12) extends from the rear wheel sprocket and is above and partially around the main chain sprocket (10). In addition, the main drive chain extends above the first tensioner sprocket (11a) and below the second tensioner sprocket (11b) before returning to the rear wheel sprocket.

[0092] When torque is applied to the main chain sprocket (10), the upper part of the drive chain is tensioned, while the slack of the lower part is absorbed by the chain tensioner.

[0093] The chain tensioner can be protected by a cover mounted to the housing.

[0094] Figure 6 The second side view shown illustrates multiple ones of the input drive elements of the drive system. Starting from the crankshaft (3), the crankshaft wheel (6) that is unidirectionally rotationally connected to the crankshaft via a one-way clutch meshes with the input shaft wheel of the input shaft (4a) connected to the internal gear (4). The input shaft wheel is rotationally connected to the input shaft (4a) and is coaxial with it. In Figure 6 the input shaft wheel is hidden behind the input wheel (18). The crankshaft can drive the input shaft of the internal gear but cannot be driven by the input shaft. In addition, the crankshaft flywheel is in the direction opposite to the driving direction.

[0095] The electric motor (5) is arranged above the crankshaft and the internal gear. The motor output shaft (5a) is connected to a first reduction gear (5c) that is a planetary gear. The rotational speed of the output shaft (5a) is reduced before being connected to the internal gear. The output part of the first reduction gear is the planet carrier of the planetary gear, and the planet carrier is fixed to the motor wheel (17). The second drive chain (14) connects the motor wheel (17) to the input wheel (18) arranged coaxially with the input shaft wheel (4a) and is unidirectionally rotationally connected to the input shaft wheel via a second one-way clutch (22). The second one-way clutch allows the motor to drive the input shaft of the internal gear but prevents it from being driven by the input shaft.

[0096] Figure 6Further shown is a second chain tensioner (19) having a first chain guide and a second chain guide (19a, 19b) arranged to push a second drive chain towards the center from respective sides. The first chain guide is static while the second chain guide is spring-loaded towards a cover (not shown).

[0097] The motor wheel (17) includes a rotary bearing (19c) at its center. The inner part of the rotary bearing has a through-hole. To hide the mechanical parts, a cover (not shown here) is mounted on this side (i.e., towards the drawing plane). The cover includes a fixed shaft that penetrates the through-hole of the rotary bearing and supports the motor wheel (17) and the planet carrier when fixed to the housing. Since there is some slack in the planet carrier, when the rotary bearing is not supported in the cover, the rotary bearing will drop towards the input shaft (4a). In this position, the tension in the chain is small or non-existent, thus allowing for easy assembly of the chain. The fixed shaft has a tapered end that can easily enter the center of the rotary bearing when the cover is being installed, and since the rotary bearing is now supported by the wheel shaft, to finally install the cover in the correct position, the rotary bearing (19c) needs to be moved away from the input shaft (4a) by the amount required to tension the second drive chain. The torsion spring that tensions the second chain guide has a free end that can be easily arranged inside the cover before pressing the cover into its final position.

[0098] Both one-way clutches (21, 22) are ramp clutches.

[0099] A gear shifter in the form of an electric actuator is arranged behind Figure 5 the first pedal arm (3a) and the cover and is configured to rotate a shift wheel shaft in an internal gear (4).

[0100] In the exemplary embodiment, a plurality of 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 these features necessarily must be included together in all embodiments of the present invention. On the contrary, features described with reference to different embodiments should not be construed as mutually exclusive. As will be readily understood by those skilled in the art, the inventors have contemplated embodiments that combine any subset of the features described herein and that are not explicitly mutually dependent and are part of the intended disclosure. However, an explicit description of all such embodiments would not aid in understanding the principles of the present invention, and thus some feature arrangements are omitted for simplicity or conciseness.

Claims

1. A pedal - propelled vehicle transmission system (1) comprising a housing (2), said pedal - propelled vehicle transmission system comprises: - a crankshaft (3); - an internal multi - speed gear (4) having a coaxial input shaft (4a) and output shaft (4b); - an electric motor (5) having an output shaft (5a), wherein the crankshaft, the input and output shafts of the internal multi - speed gear, and the output shaft of the electric motor are arranged in parallel, wherein both the crankshaft and the electric motor are arranged to drive the input shaft of the internal multi - speed gear in the same direction of rotation.

2. The pedal - propelled vehicle transmission system according to claim 1, comprising a crankshaft gear (6) and an input shaft gear (7), the crankshaft gear being coaxial with the crankshaft and the input shaft gear being coaxial with the input shaft of the internal multi - speed gear, wherein, the crankshaft gear is configured to drive the input shaft gear.

3. The pedal - propelled vehicle transmission system according to claim 2, wherein, the crankshaft gear and the input shaft gear are meshing spur gears.

4. The pedal - propelled vehicle transmission system according to any one of the preceding claims, comprising a main chain sprocket (10) configured to rotate in a direction opposite to the output shaft (4b) of the internal multi - speed gear.

5. The pedal - propelled vehicle transmission system according to claim 4, wherein, the housing includes a chain tensioner (11) arranged to tension a main drive chain (12) extending over the main chain sprocket.

6. The pedal - propelled vehicle transmission system according to claim 5, wherein, the chain tensioner includes a first tensioner sprocket (11a) arranged coaxial with the crankshaft.

7. The pedal - propelled vehicle transmission system according to any one of the preceding claims, comprising a second drive chain (14) interconnecting the electric motor and the input shaft of the internal multi - speed gear.

8. The pedal - propelled vehicle transmission system according to any one of the preceding claims, wherein, the housing is oil - filled.

9. The pedal - propelled vehicle transmission system according to any one of the preceding claims, comprising a torque limiter configured to rotationally fix the crankshaft gear (6) to a crank sleeve (20) below a torque limit and rotationally release the crankshaft gear (6) from the crank sleeve (20) above the torque limit.

10. The pedal - propelled vehicle transmission system according to claim 9, wherein, the crankshaft gear (6) includes radially arranged first ratchet teeth (31a).

11. The pedal - propelled vehicle transmission system according to claim 10, comprising second ratchet teeth (32a) radially fixed to the crank sleeve (20), wherein the first ratchet teeth (31a) and the second ratchet teeth (32a) face each other in the longitudinal direction of the crankshaft (3).

12. The pedal-propelled vehicle transmission system according to claim 11, comprising a disc spring (33) configured to urge the first ratchet teeth (31a) and the second ratchet teeth (32a) against each other.

13. The pedal-propelled vehicle transmission system according to any one of claims 9 to 12, wherein, the crankshaft wheel includes a first axial thrust surface (31b).

14. The pedal-propelled vehicle transmission system according to claim 13, comprising a second axial thrust surface (32b) arranged to be radially fixed to the crank sleeve (20), wherein the first axial thrust surface (31b) and the second axial thrust surface (31b, 32b) face each other in the longitudinal direction of the crankshaft (3).

15. The pedal-propelled vehicle transmission system according to any one of claims 9 to 14, wherein, the crankshaft wheel (6) includes a first radial thrust surface (31c) and a second radial thrust surface (32c) arranged to be radially fixed to the crank sleeve (20), wherein the first radial thrust surface (31c) and the second radial thrust surface (32c) face each other in the radial direction of the crankshaft (3).

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