NO20230877A1

NO20230877A1 - Pedally propelled vehicle drive system

Info

Publication number: NO20230877A1
Application number: NO20230877A
Authority: NO
Inventors: Knut Tore Ljøsne
Original assignee: Mont Invest 30 As
Priority date: 2023-08-17
Filing date: 2023-08-17
Publication date: 2025-02-18
Also published as: WO2025037986A1; TW202513405A

Description

PEDALLY PROPELLED VEHICLE DRIVE SYSTEM

TECHNICAL FIELD

[0001] The present invention relates to a drive system for pedally propelled vehicles, and more specifically hybrid drive systems comprising an electric motor where energy transmitted to the wheels can be delivered by a rider, by the electric motor, 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 electric motors in either the front or the back wheel. More and more pedelecs now have an electric motor 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 electric motor 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] US5836414 A discloses a manpower-assisting power apparatus equipped with a differential gear mechanism preferably comprising a pedal drive bevel gear, a motor drive bevel gear, and a pair of corresponding small bevel gears driving a rotary output member.

[0006] US2017217538 A1 discloses a controller that can be mounted on a bicycle including a first transmission having at least two shift stages and configured to change a ratio of rotation of a wheel to rotation of a crank, a motor that provides assistance to human power input to the crank, and a second transmission configured to transmit a rotation force from the motor to a 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.

[0007] EP3012181 A1 discloses a mid-motor drive system for an electric bicycle, which includes a left shell 1, a right shell 2, a motor assembly 3, a gear reduction apparatus 4, a torque sensor 5, a central shaft 7, a controller 8, and a crankset 9, and further includes a planetary gear increase apparatus 6.

[0008] US2015080163 A1 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.

[0009] 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, the MR fluid clutch apparatus controllable to transmit a variable amount of assistance force via an output thereof.

[0010] WO2012128639A1 and WO2020130841 disclose multi-speed gear systems for a pedally propelled vehicle.

[0011] WO2021125972A1 discloses an integrated crank drive system for a pedally propelled vehicle.

SHORT SUMMARY

[0012] The present invention as claimed solves a number of the problems associated with present crank drives.

[0013] In some embodiments the invention is a compact, distributed, pedally propelled drive train system comprising both the crank shaft, an electric motor and an internal multispeed gear.

[0014] In some embodiments the drive train system is modular, allowing replacement or maintenance of the electric motor without removing the crank drive.

[0015] In some embodiments the combined torque from the crank shaft and the electric motor is limited to a pre-defined value. By reducing the peak torque input to the drive components, the drive train components, such as an internal multi-speed gear system, can be made smaller and lighter. For the vehicles in question the weight is of great importance for the driving experience and energy consumption. Further, the price may be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Fig. 1 illustrates in a side view an embodiment of a pedally propelled vehicle drive train 1.

[0017] Fig. 2 illustrates in a top view the embodiment of Fig. 1.

[0018] Fig. 3 is a combined section view and isometric view of an embodiment of the invention. The crank axle 3 and elements arranged co-axially on the crank axle are shown in a section view to better illustrate the torque transfer from any of the crank arms 3a, 3b and the electric motor 5 to the output element 10.

[0019] Fig. 4 illustrates in a detailed schematic view an embodiment of the torque limiter and one-way clutches.

[0020] Fig. 5 illustrates an embodiment of the crankshaft wheel 6 configured to constitute an element of the torque limiter. Cogs for meshing with the input shaft wheel 7 have not been indicated but may be arranged on the circumference of the wheel.

[0021] Fig. 6 is a perspective view of the pedally propelled vehicle drive train 1 of Fig. 1 and B.

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 a first independent embodiment EM 1, a pedally propelled vehicle drive train 1 comprises;

- a crankshaft 3,

- a multi-speed gear system 4 with gear input and output shafts 4a, 4b.

- an electric motor 5 with a motor output shaft 5a,

wherein the motor output shaft 5a is arranged perpendicular to the crankshaft 3 and the gear input and output shafts 4a, 4b.

[0025] When the motor axle is perpendicular to the internal gear system, the electric motor may be arranged remote from the crank drive. As long as the motor axle reaches into the crank drive, and is able to transfer torque by rotation to the drive components in the crank drive, the electric motor may be arranged in different locations on the pedally propelled vehicle, such as e.g., in the bottom of the downtube, in the bottom of the seattube, in the top of the seat tube, integrated in the seat with the motor axle running through the seat-tube, in a separate housing between the seat tube and the down tube.

[0026] In a first dependent embodiment, the pedally propelled vehicle drive train 1 comprises a drive output axle 15, wherein the gear output shaft 4b is configured to rotate the drive output axle 15, and wherein both the crankshaft 3 and the motor output shaft 5a are configured to rotate the gear input shaft 4a.

[0027] An output element 10, such as a sprocket for a chain, a pulley for a belt or other means for transferring torque to a drive wheel of pedally propelled vehicle may be fixed to the output axle.

[0028] In a second dependent embodiment, that may be combined with the first dependent embodiment, the pedally propelled vehicle drive train 1 comprises a crank sleeve 20 arranged co-axially around the crank shaft 3, wherein the crank sleeve 20 is configured to rotate the gear input shaft 4a. Both the crankshaft 3 and the motor output shaft 5a are configured to rotate the crank sleeve.

[0029] In a third dependent embodiment, that may be combined with the second dependent embodiment, the crank axle 3 is one-way rotationally connected to the crank sleeve 20 via a first one-way clutch 21, such as a sprag clutch. This allows the crank axle to drive the crank sleeve, but prevents the crank sleeve from driving the crank axle.

[0030] In a fourth dependent embodiment, that may be combined with the second or third dependent embodiments, the motor output shaft 5 is one way rotationally connected to the crank sleeve 20 via a second one-way clutch 22. This allows the motor output shaft to drive the crank sleeve but prevents the crank sleeve from driving the motor output shaft.

[0031] In a fifth dependent embodiment, that may be combined with any of the first to the fourth dependent embodiments, the pedally propelled vehicle drive train 1 comprises a bevel gear wherein a pinion gear 5b of the bevel gear is fixed to the motor output shaft 5a and a conical gear 23 of the bevel gear is arranged co-axially outside the crank sleeve 20.

[0032] In a sixth dependent embodiment, that may be combined with the fifth dependent embodiment the second one-way clutch 22 is arranged between the conical gear and the crank sleeve 20.

[0033] In a seventh dependent embodiment, that may be combined with any of the first to the sixth dependent embodiments, the pedally propelled vehicle drive train 1, comprises a torque limiter between the crank sleeve 20 and the gear input shaft 4a, configured to limit the combined torque from the crank shaft 3 and the electric motor 5 to a pre-defined torque threshold.

[0034] In an eight dependent embodiment, that may be combined with any of the embodiments above, the motor output shaft 5a comprises first and second mutually mating sub-shafts 5a1, 5a2, wherein the first and second sub-shafts are configured to be interconnected by a quick release coupling , allowing the electric motor 5 to be released from the crank shaft and the multispeed gear system 4.

[0035] In an eight dependent embodiment, that may be combined with any of the embodiments above, wherein the gear input and output shafts 4a, 4b have a common rotation axis.

[0036] In an eight dependent embodiment, that may be combined with any of the embodiments above, wherein the electric motor 5 is configured to be arranged at least partly in a down tube or seat tube of a diamond frame of a pedally propelled vehicle.

[0037] In a ninth dependent embodiment, that may be combined with any of the embodiments above, the pedally propelled vehicle drive train 1 comprises a longitudinal battery pack configured to drive the electric motor 5 and to be arranged above the electric motor in the down tube or seat tube.

[0038] In a second independent embodiment, a pedally propelled vehicle comprises a pedally propelled vehicle drive train 1 according to any of the claims above.

[0039] In an independent embodiment illustrated in Fig. 1 and B, the main elements of the pedally propelled vehicle drive train 1 are shown in a side view and a top view. The crankshaft 3 comprises first and second pedal arms 3a, 3b connected to respective ends of the crank axle in order to rotate the crank axle when the pedal arms are operated by a rider. The crank axle has a drive direction indicated by an arrow next to the right pedal arm 3a. When the crank axle is operated in the drive direction, the output element 10, in this case a sprocket for a chain, is driven in the same rotational direction as the crank shaft via the multi-speed gear 4. Different rotational speed ratios for the output element with respect to the crank axle 3 can therefore be altered by selecting different gear ratios in the multi-speed gear.

[0040] The output element 10 can also be driven by the electric motor 5 via the multispeed gear 4. Thus, torque from both the crank axle 3 and the electric motor 5 are transferred through the multi-speed gear 4.

[0041] More details of the embodiment can be seen in Fig. 3, where a cylindrically shaped crank sleeve 20 is arranged about the crank axle 3. The crank sleeve is one-way rotationally connected to the crank axle via a first one way clutch 21, where the crank axle will rotate the crank sleeve as long as the crank sleeve does not rotate faster than the crank. The first one-way clutch may be a sprag clutch.

[0042] Opposite the first one-way clutch, a crankshaft wheel 6, is connected to the crank sleeve 20, and when the crank sleeve rotates, the crankshaft wheel meshing with an input shaft wheel 7 on the input shaft 4a of the multi-speed gear 4 rotates with crank sleeve in order to transfer input torque to the internal gear from the crank via the crank sleeve.

[0043] The electric motor 5 has a rotating motor axle 5a arranged perpendicularly to the crank shaft 3 and fixed to a pinion gear of a bevel gear comprising also a conical gear meshing with the pinion gear and arranged co-axially about the crank sleeve 20. The crank sleeve 20 is one-way rotationally connected to the conical gear via a second one way clutch 22, where the motor axle 5a will rotate the crank sleeve as long as the crank sleeve does not rotate faster than the motor axle. The second one-way clutch may be a sprag clutch.

[0044] The embodiment further comprises a torque limiter illustrated in more detail in Fig. 4. The torque limiter prevents the combined torque on the crank sleeve from the crank shaft and the electric motor from overloading multi-speed gear 4.

[0045] The first crankshaft wheel 6 comprises first ratchet teeth 31a arranged radially and facing respective second ratchet teeth 32a arranged radially on the

crank sleeve 20. A disc spring 31 kept in place by a locking ring 39 fixed to the crank sleeve 20 pushes the crankshaft wheel 6 against the ratchet sleeve 32, making sure that the first and second ratchet teeth of the torque limiter are in mesh as long as the torque across the torque limiter is below a designed value given by the resilience of the disc spring. If the torque is above the designed value, the disc spring will allow the ratchet teeth to ratchet relative each other in order to protect the components after the crank sleeve.

[0046] The crankshaft wheel 6 is axially and radially supported by a first axial trust face 31b supported by a second axial thrust face 32b and by a first radial trust face 31c supported by a second radial thrust face 32c, respectively on the ratchet sleeve 32.

[0047] The first ratchet teeth 31a, the first axial trust face 31b and first radial trust face 31c of the crankshaft wheel are illustrated in Fig. 4.

[0048] A magnetic torque sensor 36 configured to sense a torque of the crank sleeve 20 is arranged between the crank shaft 3 and the crank sleeve 20. The magnetic torque sensor may be based on the magneto-elastic effect, where the crank sleeve itself is magnetized or a magnetized element is fixed to the crank sleeve. Sensor coils not shown can be arranged outside the crank sleeve. As an alternative, the torque of the crank axle could be measured by magnetizing the crank axle or fixing a magnetized element to the crank axle.

[0049] The torque sensor may be connected to a control system in order to control power from the electric motor as a function on the torque detected by the torque sensor.

[0050] The components of the pedally propelled vehicle drive train 1 may be installed in a common housing. In an embodiment, the crankshaft 3, the multi-speed gear 4 and the electric motor 5 are all enclosed by a common housing arranged fixed to the seat tube and the down tube.

[0051] In an alternative embodiment, the crankshaft 3, the multi-speed gear 4 and a first sub-shaft of the motor output shaft 5a are arranged enclosed in the housing, while the second sub-shaft of the motor output shaft 5b and the electric motor 5 are arranged outside the housing. The second motor shaft and the electric motor may e.g., be installed fixed to the lower part of the downtube, where the first and second sub-shafts are interconnected in a quick connect interface, implemented by mating ends of the first and second motor shafts, allowing the housing to be removed without removing the motor and/or the motor to be removed without removing the housing.

[0052] The housing is not shown in the drawings.

[0053] The crankshaft 3, the internal gear 4 and it’s input and output shafts 4a, 4b and are all arranged in parallel. The main drive chain 12 driven by the output element 10 interconnects the drive train and a rear wheel sprocket 13 of a wheel of the vehicle in order to drive the wheel when driving torque is applied on the main chain sprocket of the drive train. The drive train comprises a chain tensioner 11 comprising a first tensioner sprocket 11a arranged freely rotating about the crank axle 3, and a second tensioner sprocket 11b arranged on a spring-loaded link arm 11c. In the drive direction, indicated by the stapled line in Fig. 1, the upper part of the main drive chain 12 runs from the rear wheel sprocket, over and partially around the output element 10. Further it runs over the first tensioner sprocket 11a and below the second tensioner sprocket 11b before returning to the rear wheel sprocket.

[0054] While the embodiment illustrated is configured for a chain drive, other types of drives could be used instead, such as belt drive where all elements interfacing the belt should be replaced by belt drive versions.

Claims

1. A pedally propelled vehicle drive train (1) comprising;

- a crankshaft (3)

- a multi-speed gear system (4) with gear input and output shafts (4a, 4b).

- an electric motor (5) with a motor output shaft (5a),

wherein the motor output shaft (5a) is arranged perpendicular to the crankshaft (3) and the gear input and output shafts (4a, 4b).

2. The pedally propelled vehicle drive train (1) of claim 1, comprising a drive output axle (15), wherein the gear output shaft (4b) is configured to rotate the drive output axle (15), and wherein both the crankshaft (3) and the motor output shaft (5a) are configured to rotate the gear input shaft (4a).

3. The pedally propelled vehicle drive train (1) of claim 1, comprising a crank sleeve (20) arranged co-axially around the crank shaft (3), wherein the crank sleeve (20) is configured to rotate the gear input shaft (4a).

4. The pedally propelled vehicle drive train (1) of claim 3, wherein the crank axle (3) is one-way rotationally connected to the crank sleeve (20) via a first one-way clutch (21) and the motor output shaft (5) is one way rotationally connected to the crank sleeve (20) via a second one-way clutch (22).

5. The pedally propelled vehicle drive train (1) of claim 4, comprising a bevel gear wherein a pinion gear (5b) of the bevel gear is fixed to the motor output shaft (5a) and a conical gear (23) of the bevel gear is arranged co-axially outside the crank sleeve (20) and the second one-way clutch (22) is arranged between the conical gear and the crank sleeve (20).

6. The pedally propelled vehicle drive train (1) according to any of the claims 3 to 5, comprising a torque limiter between the crank sleeve (20) and the gear input shaft (4a), configured to limit the combined torque from the crank shaft (3) and the electric motor (5) to a pre-defined torque threshold.

7. The pedally propelled vehicle drive train (1) of any of the claims above, wherein the electric motor (5) is configured to be arranged at least partly in a down tube or seat tube of a triangle frame of a pedally propelled vehicle.

8. The pedally propelled vehicle drive train (1) of claim 9, comprising a longitudinal battery pack configured to drive the electric motor (5) and to be arranged above the electric motor in the down tube or seat tube.

9. The pedally propelled vehicle drive train (1) of any of the claims above, wherein, the motor output shaft (5a) comprises first and second mutually mating sub-shafts (5a1, 5a2), wherein the first and second sub-shafts are configured to be interconnected by a quick release coupling, allowing the electric motor (5) to be released from the crank shaft and the multispeed gear system (4).

10. A Pedally propelled vehicle comprising a pedally propelled vehicle drive train (1) according to any of the claims above.