Pedal propulsion vehicle drivetrain

Abstract

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

Description

Technical Field

[0001] The present invention relates to a powertrain for a pedal-propelled vehicle and, more particularly, to a hybrid powertrain including an electric motor, wherein the energy transferred to the wheels may be delivered by the rider, the electric motor, or a combination of both. Background Art

[0002] Over the past few decades, many different so-called power-assisted bicycles have been developed, some of which have an electric motor on the front or rear wheel. Due to the advantages associated with weight distribution and the possibility of close integration with the battery and frame, more and more power-assisted bicycles now have the electric motor arranged near the crankshaft.

[0003] However, there are still many problems to be solved with current crank drives. One of them is the need for long-term reliability and reduced maintenance costs.

[0004] Only a few crank systems with integrated electric motors and multi-speed gears are disclosed. Most of them are heavy and have poor performance, which makes them suitable for only a few pedal-propelled vehicle applications.

[0005] US5836414A discloses a human-assisted 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 driving a rotating output member.

[0006] US2017217538A1 discloses a controller that can be installed on a bicycle, the controller including a first transmission having at least two gear stages and configured to change the ratio of wheel rotation to crank rotation; a motor that provides assistance to human power input to the crank; and a second transmission configured to transmit the rotational force from the motor to a power transmission path extending from the crank to the wheel without changing the ratio of wheel rotation to crank rotation.

[0007] EP3012181A1 discloses a mid-mounted motor transmission system for an electric bicycle, which comprises 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 crank set (9), and also comprises a planetary gear speed increase device (6).

[0008] 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, a planetary gear and a gear ring, two of the sun gear, the planetary gear and the 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 is arranged between the first drive source and the planetary gear unit; a second one-way clutch is arranged between the second drive source and the planetary gear unit, wherein the first direction and the second direction are set so that the output shaft of the planetary gear unit rotates in the same direction.

[0009] US2018370591A1 discloses a system for assisting a user in moving a device relative to a structure, the system comprising a magnetorheological (MR) fluid actuator unit, the magnetorheological fluid actuator unit comprising at least one torque source and at least one MR fluid clutch device, the 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 assist force via its output.

[0010] WO2012128639A1 and WO2020130841 disclose multi-speed gear systems for pedal-propelled vehicles. Summary of the invention

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

[0012] In some embodiments, the present invention is a compact, integrated pedal propulsion transmission system that includes a crankshaft, a motor, and internal multi-speed gears.

[0013] In some embodiments, torque is limited. By reducing the peak torque from the crankshaft to the drive components, the drivetrain components can be made smaller and lighter. For the vehicle in question, weight is very important for driving experience and energy consumption. In addition, the price may be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A vehicle drive system according to an embodiment of the invention is shown in a schematic side view.

[0015] Figure 2 A schematic top view is shown with Figure 1 Same embodiment. Note that the figure has been flattened to better show the various components.

[0016] Figure 3 An embodiment of a torque limiter is shown in a detailed schematic diagram.

[0017] Figure 4 An embodiment of a crankshaft wheel (6) is shown, which is configured to constitute an element of a torque limiter. Figure 2 The cogwheel with which the input shaft wheel (7) shown in Fig. 1 meshes is not shown but may be arranged on the outer rim of the wheel.

[0018] Figure 5 and Figure 6 An embodiment of a vehicle driveline is shown in an opposite side view. DETAILED DESCRIPTION

[0019] In the following description, various examples and embodiments of the present invention are described to provide a more thorough understanding of the present invention to the skilled person. The specific details described in the context of various embodiments and with reference to the accompanying drawings are not intended to be interpreted as limiting. On the contrary, the scope of the present invention is limited in the appended claims.

[0020] The embodiments described below are numbered. In addition, dependent embodiments are described that are defined with respect to the numbered embodiments. Unless otherwise specified, any embodiment that can be combined with one or more numbered embodiments can also be directly combined with any of the dependent embodiments of the mentioned numbered embodiments.

[0021] In a first embodiment EM1, the present invention is a pedal-propelled vehicle transmission system (1), such as Figure 1 and Figure 2 The transmission system comprises a housing (2), and the transmission system comprises:

[0022] - a crankshaft (3);

[0023] - an internal gear (4) having a coaxial input shaft (4a) and an output shaft (4b);

[0024] - an electric motor (5) having an output shaft (5a),

[0025] The crankshaft, the input shaft and output shaft of the internal gear and the output shaft of the electric motor are arranged in parallel.

[0026] The internal gear (4) is a multi-speed gear system.

[0027] The pedal arms (3a, 3b) driving the crankshaft are as follows Figure 2 shown.

[0028] EM2. A 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 rotational direction.

[0029] EM3. A 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.

[0030] EM4. A pedal-propelled vehicle transmission system according to EM3, wherein the crankshaft wheel and the input shaft wheel are configured to rotate in opposite directions.

[0031] EM5. A pedal-propelled vehicle transmission system according to EM4, wherein the crankshaft wheel and the input shaft wheel are meshing cogwheels.

[0032] EM6. A pedal-propelled vehicle transmission system according to any of the preceding embodiments, comprising a main chain sprocket (10) configured to rotate in opposite directions relative to the output shaft (4b).

[0033] EM7. A pedal-propelled vehicle transmission system according to Example 6, wherein the main chain sprocket is arranged non-coaxially relative to the output shaft (4a).

[0034] EM8. The pedal-propelled vehicle transmission system according to Example 7 includes a main sprocket axle (15) arranged parallel to the output shaft, wherein the transmission system also includes 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.

[0035] EM9. A pedal-propelled vehicle transmission system according to Example 8, wherein the output shaft wheel and the main wheel are meshing cogwheels and rotate in opposite directions.

[0036] EM10. A pedal-propelled vehicle transmission system according to any one of the aforementioned embodiments, partially comprising a main drive chain (12), which extends on a main chain sprocket and is arranged to interconnect the main chain sprocket with a rear wheel sprocket (13), which is located on the rear wheel of a pedal-propelled vehicle on which the transmission system is installed.

[0037] EM11. A pedal-propelled vehicle transmission system according to EM10, wherein the housing comprises a chain tensioner (11) arranged to tension a main drive chain (12) extending on a main chain sprocket.

[0038] EM12. A pedal-propelled vehicle transmission system according to EM11, wherein the chain tensioner comprises a first tensioner sprocket (11a) arranged coaxially with the crankshaft.

[0039] EM13. A pedal-propelled vehicle transmission system according to EM11 or EM12, wherein the chain tensioner comprises a second tensioner sprocket (11b) arranged below the crankshaft.

[0040] EM14. A pedal-propelled vehicle transmission system according to any one of the aforementioned embodiments, comprising a crank sleeve (20) and a one-way clutch (21), wherein the crank sleeve is coaxially arranged on the outside of the crank shaft, and the one-way clutch is configured to allow the crank shaft to rotate the crank sleeve in one rotational direction and rotate the flywheel in another rotational direction.

[0041] EM15. A pedal-propelled vehicle transmission system according to EM14, wherein the one-way clutch is arranged inside the crank sleeve.

[0042] As a first alternative to embodiments EM14 and EM15, a one-way clutch is arranged between the input shaft wheel (7) and the input shaft (4a).

[0043] EM16. A pedal-propelled vehicle transmission system according to EM14 or EM15, wherein the one-way clutch is a sprag clutch.

[0044] EM17. A 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).

[0045] Overload can be a major problem associated with the drivetrain of a pedal-propelled vehicle. Although a rider pedaling hard may not directly cause an overload, other aspects, such as hitting the crank arm against an obstacle, can cause harmful peak torques to the drivetrain. The torque limiter according to the following embodiment is instantaneous and arranged upstream of the drivetrain to protect as many components as possible. In addition, it self-heals immediately after an incident and allows continued operation when the peak torque drops below a predefined torque limit.

[0046] EM18. A 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 a torque limit, and to rotationally release the crankshaft wheel (6) from the crank sleeve (20) above the torque limit.

[0047] EM19. A pedal-propelled vehicle transmission system according to EM18, wherein the crankshaft wheel (6) includes radially arranged first ratchet teeth (31a).

[0048] EM20. A pedal-propelled vehicle transmission system according to EM19, comprising a second ratchet tooth (32a) radially fixed to the crank sleeve (20), wherein the first ratchet tooth (31a) and the second ratchet tooth face each other in the longitudinal direction of the crank shaft (3).

[0049] EM21. A pedal-propelled vehicle transmission system according to EM20, comprising a coil spring (33) configured to push the first ratchet teeth and the second ratchet teeth (31a, 32a) against each other.

[0050] EM22. A 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).

[0051] EM23. The pedal-propelled vehicle transmission system according to EM22 comprises 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 crank shaft (3).

[0052] EM24. A 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).

[0053] EM25. The pedal-propelled vehicle transmission system according to EM24 comprises 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 crank shaft (3).

[0054] EM26. A pedal-propelled vehicle transmission system according to EM25, comprising a ratchet sleeve (32) arranged to be coaxially fixed to a crank sleeve (20), wherein the ratchet sleeve comprises a second ratchet tooth (32a), a second axial thrust surface (32b) and a first radial thrust surface (32c).

[0055] 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 a longitudinal position of the crankshaft (3).

[0056] EM27. A 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 ​​50Nm, 70Nm, 100Nm, 120Nm, 150Nm, 200Nm.

[0057] EM28. A pedal-propelled vehicle transmission system according to any one of embodiments EM18 to EM27, wherein the disc spring pushes the first ratchet tooth (31a) and the second ratchet tooth against each other with a force of at least any one of 3000N, 5000N, 7000N, 10000N, 12000N, 15000N, 20000N.

[0058] EM29. A pedal-propelled vehicle transmission system according to any one of embodiments EM14 to EM28, comprising a torque sensor (36) configured to sense torque between the crankshaft (3) and the crank sleeve (20).

[0059] EM30. A pedal-propelled vehicle transmission system according to EM29, wherein the torque sensor is a magnetic torque sensor.

[0060] 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).

[0061] EM31. A pedal-propelled vehicle transmission system according to any one of the aforementioned embodiments, comprising 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.

[0062] EM32. A pedal-propelled vehicle transmission system according to EM31, comprising a second drive chain (14) interconnecting the motor wheel and the input wheel.

[0063] EM33. A pedal-propelled vehicle transmission system according to any one of EM31 and EM32, comprising 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 another rotational direction.

[0064] EM34. A 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).

[0065] EM35. A pedal-propelled vehicle transmission system according to EM33 or 34, wherein the second one-way clutch is a sprag clutch.

[0066] EM36. A pedal-propelled vehicle transmission system according to any of the preceding embodiments, wherein the housing is oil-filled.

[0067] EM37. A pedal-propelled vehicle transmission system according to any of the preceding embodiments, wherein the internal gear comprises one or more planetary gear sets.

[0068] In a subordinate embodiment, the motor wheel (17) is connected to the planet carrier of the planetary gear.

[0069] In a second slave embodiment, the output shaft (5a) of the motor drives the sun gear of the planetary gear set.

[0070] EM38. A pedal-propelled vehicle transmission system according to any of the preceding embodiments, comprising a gear shifter (16) arranged to shift gears within an internal gear, for example by rotating a shift axle within the internal gear.

[0071] EM39. The pedal-propelled vehicle transmission system according to any one of the aforementioned embodiments EM32 to EM38, comprising a second chain tensioner (19) configured to tension the second drive chain (14).

[0072] In a first subsidiary embodiment, a pedal-propelled vehicle transmission system comprises a cover arranged to cover a chain tensioner and to 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.

[0073] In a second subsidiary embodiment, the cover is configured to be connected to the motor wheel (17) before reaching its final position when installed.

[0074] In a third subsidiary embodiment, the cover comprises an axle or shaft extending from the cover, the axle or shaft being configured to enter into a through hole of a rotary bearing fixed to the motor wheel (17).

[0075] exist Figure 1 and Figure 2 , a specific embodiment of a pedal-propelled vehicle transmission system is shown. Figure 1 is a partially transparent schematic side view showing the main elements of the drive train. Figure 2 is shown with Figure 1 A partially transparent top view in cross-section of the same elements. The crankshaft (3) comprises a first pedal arm and a second pedal arm (3a, 3b). Furthermore, 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 a frame of a 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 comprises a chain tensioner (11), which comprises a first tensioner sprocket (11a) arranged to rotate freely around the crankshaft axle (3) and a second tensioner sprocket (11b) arranged on a spring-loaded connecting rod arm (11c). In the case of a vehicle having a plurality of chain sprockets (11a and 11b) arranged to rotate freely around the crankshaft axle (3), the crankshaft (3) comprises a first tensioner sprocket (11a) and a second tensioner sprocket (11b) arranged on a spring-loaded connecting rod arm (11c). Figure 1 In the driving direction indicated by the gutter in FIG. 1 , the upper portion of the main drive chain (12) extends from the rear wheel sprocket over the main chain sprocket (10) and partially around the main chain sprocket. In addition, the main drive chain extends over the first tensioner sprocket (11a) and under the second tensioner sprocket (11b) before returning to the rear wheel sprocket.

[0076] When torque is applied to the main chain sprocket (10), the upper portion of the drive chain is tensioned while the slack in the lower portion is absorbed by the chain tensioner.

[0077] The main chain sprocket (10) is arranged on a ball bearing located on a main chain wheel shaft (15), which is arranged to be fixed to the housing (2). The main chain sprocket (10) is further rotationally fixed to a main wheel (15c), which is arranged inside the main chain sprocket (10) on the main chain wheel 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 cogwheels. Therefore, the main chain sprocket (10) is directly driven by the output shaft (4b). In the current configuration, the rotation direction of the main chain sprocket is opposite to that of the output shaft.

[0078] The input shaft (4a) of the internal gear can be driven by the crankshaft (3) or the electric motor (5) or both.

[0079] 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 wheel shaft (4a) and is unidirectionally rotatably connected to the input wheel 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 wheel shaft (4a) allows the motor to drive the input wheel shaft (4a) instead of the input wheel shaft driving the motor.

[0080] Likewise, the crankshaft (3) can drive the input axle (4a) in a rotational direction that is the same as the direction in which the motor can drive the input axle.

[0081] The crankshaft wheel (6) is unidirectionally rotatably connected to the crankshaft (3) via a one-way clutch radially arranged between the crankshaft (3) and the crankshaft wheel (6). The crankshaft wheel (6) is meshed with an input shaft wheel (7) which is connected to the input shaft (4a) of the internal gear (4) and is axially arranged inside the input wheel (18).

[0082] Figure 1 and Figure 2 The pedal-propelled vehicle drive system also includes Figure 3 The torque limiter is shown in more detail in FIG. The torque limiter prevents the crankshaft from overloading the internal components.

[0083] The first crankshaft wheel (6) comprises first ratchet teeth (31a) which are radially arranged and face corresponding second ratchet teeth (32a) which 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). In addition, the crank sleeve is fixed to the crankshaft (3) with a second end opposite to the first end.

[0084] The disc spring (31), held in place by a locking ring (39) fixed to the crank sleeve (20), pushes the crankshaft wheel (6) against the input shaft wheel (7), thereby ensuring that the first and second ratchet teeth of the torque limiter are engaged 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 loosen from each other to protect the components behind the crank drive, such as internal gears, sprag clutch, etc.

[0085] The crankshaft wheel (6) is supported axially and radially on the ratchet sleeve (32) respectively via 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).

[0086] The first ratchet tooth (31a), the first axial thrust surface (31b) and the first radial thrust surface (31c) of the crankshaft wheel are as follows: Figure 4 shown.

[0087] A magnetic torque sensor (36) is arranged outside and between the first end and the second end of the crank sleeve (20), and is configured to sense torque between the crankshaft (3) and the crank sleeve (20).

[0088] exist Figure 5 and Figure 6 In a specific embodiment of a pedal-propelled vehicle transmission system shown in a relative first side view and a second side view, it can be seen that 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) and the electric motor (5) and the electric motor output shaft (5a) are arranged in parallel. The housing (2) is configured to be installed 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 that the wheel is driven when a driving torque is applied to the main chain sprocket of the transmission system. The internal gear is a multi-speed gear system, for example, it can be an adaptation of the gear system disclosed in WO2020130841A1.

[0089] exist Figure 5In the first side view, which can be seen as the output drive side, we can see that the chain tensioner (11) is an integrated part of the transmission system, which means that no additional chain tensioner is required externally and the work related to installation and maintenance can be reduced. In most prior art, the chain tensioner is located near the rear wheel sprocket or hub or is installed as a separate tensioner in the crank area.

[0090] The chain tensioner comprises a first tensioner sprocket (11a) arranged to rotate freely around a crank wheel axle (3), and a second tensioner sprocket (11b) arranged on a spring-loaded link arm (11c). In the driving direction indicated by the gutter, the upper part of the main drive chain (12) extends from the rear wheel sprocket and is 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.

[0091] When torque is applied to the main chain sprocket (10), the upper portion of the drive chain is tensioned while the slack in the lower portion is absorbed by the chain tensioner.

[0092] The chain tensioner may be protected by a cover mounted to the housing.

[0093] Figure 6 The second side view shown shows a plurality of input drive elements of the transmission system. Starting from the crankshaft (3), a crankshaft wheel (6) connected to the crankshaft in one direction in rotation via a one-way clutch meshes with an input shaft wheel connected to the input shaft (4a) of the internal gear (4). The input shaft wheel is connected to the input shaft (4a) in rotation and is coaxial with it. Figure 6 In the case of a gearbox, the input shaft flywheel 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 opposite direction to the driving direction.

[0094] The electric motor (5) is arranged above the crankshaft and the internal gear. The motor output shaft (5a) is connected to the first reduction gear (5c) which is a planetary gear. The rotation 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 planetary carrier of the planetary gear, which 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 wheel shaft (4a) and is connected to the input wheel shaft in a unidirectional rotation through the 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.

[0095] Figure 6Further shown is a second chain tensioner (19) having a first chain guide and a second chain guide (19a, 19b) arranged to push the second drive chain from the respective sides towards the center. The first chain guide is static, while the second chain guide is spring loaded towards a cover not shown.

[0096] The motor wheel (17) comprises a rotary bearing (19c) in its center. The inner part of the rotary bearing has a through hole. In order to hide the mechanical part, a cover (not shown here) is mounted on this side (i.e. towards the plane of the drawing). The cover comprises a fixed shaft which penetrates the through hole of the rotary bearing and supports the motor wheel (17) and the planet carrier when fixed to the housing. Since the planet carrier has some slack, the rotary bearing will drop towards the input shaft (4a) when it is not supported in the cover. In this position, there is little or no tension in the chain, allowing easy assembly of the chain. The fixed shaft has a tapered end which can easily enter the center of the rotary bearing when the cover is installed, and since the rotary bearing is now supported by the wheel axle, the final installation of the cover in the correct position requires moving the rotary bearing (19c) away from the input shaft (4a) and tensioning the second drive chain by the required amount. The torsion spring that tensions the second chain guide has a free end which is easy to arrange inside the cover before pressing the cover into the final position.

[0097] Both one-way clutches (21, 22) are sprag clutches.

[0098] The gear shifter in the form of an electric actuator is arranged in Figure 5 The first pedal arm (3a) and the rear of the cover are configured to rotate the shift wheel shaft in the internal gear (4).

[0099] In the exemplary embodiment, a plurality of features and details are shown in combination. The fact that several features are described about a particular example should not be interpreted as implying that these features must necessarily be included together in all embodiments of the present invention. On the contrary, the features described with reference to different embodiments should not be interpreted as mutually exclusive. As will be readily understood by those skilled in the art, the inventors have considered embodiments that are combined with any feature subset described herein and are not explicitly interdependent and are part of the intended disclosure. However, a clear description of all such embodiments would not contribute to an understanding of the principles of the present invention, and therefore some feature arrangements have been omitted for simplicity or brevity.

Claims

1. A pedal-propelled vehicle transmission system (1), comprising a housing (2), the pedal-propelled vehicle transmission system comprising: - crankshaft (3); - an internal multi-speed gear (4) having a coaxial input shaft (4a) and an output shaft (4b); - an electric motor (5) having an output shaft (5a), wherein the crankshaft, the input shaft and the output shaft of the internal multi-speed gear and the output shaft of the electric motor are arranged in parallel, wherein the crankshaft and the electric motor are both arranged to drive the input shaft of the internal multi-speed gear in the same rotational direction, The pedal-propelled vehicle transmission system (1) comprises 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 multi-speed gear. Wherein, the motor wheel (17) is connected to the planet carrier of the planetary gear, The output shaft (5a) of the electric motor (5) drives the sun gear of the planetary gear set. The pedal-propelled vehicle transmission system further comprises a main chain sprocket (10) configured to rotate in an opposite direction relative to an output shaft (4b) of the internal multi-speed gear.

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

3. The pedal-propelled vehicle transmission system according to claim 2, wherein: The crankshaft wheel and the input shaft wheel are meshing cogwheels.

4. The pedal-propelled vehicle transmission system according to claim 1, wherein: The housing comprises a chain tensioner (11) arranged to tension a main drive chain (12) extending over the main chain sprocket.

5. The pedal-propelled vehicle transmission system according to claim 4, wherein: The chain tensioner comprises a first tensioner sprocket (11a) arranged coaxially with the crankshaft.

6. A pedal-propelled vehicle driveline according to any one of claims 1 to 5, comprising a second drive train (14) interconnecting the electric motor with the input shaft of the internal multi-speed gear.

7. A pedal-propelled vehicle transmission system according to any one of claims 1 to 5, wherein: The housing is oil filled.

8. A pedal-propelled vehicle transmission system according to claim 2 or 3, comprising a torque limiter, which is configured to rotationally fix the crankshaft wheel (6) to the crank sleeve (20) below a torque limit and to rotationally release the crankshaft wheel (6) from the crank sleeve (20) above the torque limit.

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