WO2022236797A1

WO2022236797A1 - A torque sensing system, a conversion kit with a torque sensing system, and a vehicle with a torque sensing system

Info

Publication number: WO2022236797A1
Application number: PCT/CN2021/093767
Authority: WO
Inventors: Yuk Chun Joh CHAN
Original assignee: Cyc Motor Limited
Priority date: 2021-05-14
Filing date: 2021-05-14
Publication date: 2022-11-17

Abstract

A torque sensing system (50) is disclosed as including a steel workpiece (1) fixedly engageable with a bicycle spindle (2), a strain gauge (5) fixedly received within a space (26) of the steel workpiece (1) for simultaneous rotation with the steel workpiece (1) and the bicycle spindle (2) about a common longitudinal axis of rotation (R-R), and a one-way clutch (3) received within a space of the steel workpiece (1) for transmitting mechanical power inputted by a rider, and in which an axis (r ₃-r ₃) perpendicular to a major surface (32) of the strain gauge (5) is parallel to the common longitudinal axis of rotation (R-R). A conversion kit including such a torque sensing system (50) for converting a manually-driven bicycle to an electric or power-assisted bicycle (100) and the bicycle (100) including such a torque sensing system (50) are also disclosed.

Description

A Torque Sensing System, a Conversion Kit with a Torque Sensing System, and a Vehicle with a Torque Sensing System

This invention relates to a torque sensing system, in particular, such a torque sensing system suitable (but not limited) for sensing the torque of a vehicle spindle (e.g. a bottom bracket spindle of a bicycle) , a conversion kit with such a torque sensing system suitable (but not limited) for converting a manually-driven vehicle (e.g. a manually-driven bicycle) to an electric or power-assisted vehicle (e.g. an electric or power-assisted bicycle) , and a vehicle (e.g. an electric or power-assisted bicycle) with such a torque sensing system.

Background of the Invention

There are in existence motorized vehicles (e.g. motorized bicycles) with an attached motor or engine and transmission used either to power the vehicle unassisted or to assist with pedalling. In a power-assisted bicycle (also called an “ebike” ) , both pedals and a connected drive for rider-powered/pedal-powered propulsion are still retained. The pedals are connected with a bicycle central shaft (also called a bicycle central spindle) to allow a rider to pedal so as to propel the bicycle. When the rider pedals, a torque is applied via the pedals on the central spindle. A strain gauge is used for measuring the torque applied on the central spindle caused by pedalling of the pedals, to act as one factor for determining the power to be outputted by the motor or engine to assist the rider in propelling the bicycle (e.g. such as when ascending slopes or in long journeys) . Another factor for making such a determination is the cadence (pedaling speed) signal.

In one existing pedal assist sensor design, a deformable body is positioned between the central spindle and the sprocket, whereby deformation of the deformable body is measured by a strain gauge. The signals generated by the strain gauge are subsequently transmitted to the motor system controller via a contact-type electrical brush. A shortcoming of such an arrangement is that the strain gauge usually takes up physical space otherwise available for the spindle, thus comprising the physical strength of the spindle. In addition, the axial dimension of the spindle will also be compromised if the strain gauge is to be put on the circumferential surface as it is not possible to implement this arrangement in the bottom bracket area of the motor system.

It is also common to convert a manually-driven vehicle (e.g. a conventional manually-driven bicycle) to an electric or power-assisted vehicle (e.g. an electric or power-assisted bicycle) by installing a conversion kit onto such a conventional manually-driven bicycle. The conversion motor in question is to be installed to the bottom bracket area of a bicycle. In existing conversion kits, a strain gauge is usually provided on an outer circumferential surface of the bicycle central spindle. According to a generally accepted BSA standard, the internal diameter of a bottom bracket into which the bicycle central spindle is to be inserted is around 33 mm.

There are the following two common spline interface standards relating to bicycle spindles and cranks:

(1) Square Tapered

This is the most common spindle spline standard choice for lower-cost bicycles. A front view of a square-tapered spindle with standard dimensions is shown in Fig. 1A. The smallest diameter on the spindle shaft is about 16mm, thus making this standard popular among ebike motor designers, as this standard offers the most radial space for such electronic components as the torque sensing electronic components. However, this standard is becoming an inferior choice among riders due to the smaller diameter of the spindle offering significantly less mechanical strength in the crankset assembly, making the spindle prone to failure especially under off-road usage.

(2) Spline Interface

Spline interface (ISIS spline) is becoming a more popular choice of spindle spline choice among riders due to the stronger strength offered by the larger shaft diameter, the smallest outer diameter of the spindle shaft (as measured at the location where the spindle joins the crank) being about 21 mm, as shown in the front view of an ISIS standard spline spindle in Fig. 1B. However, this offers less radial space for the required electronics that make up the torque sensing system. Hence in the mid-drive conversion market, so far as being aware, there has not been a product that combines the feature of splined spindle and torque sensor for a mid-drive conversion motor system.

It is thus an object of the present invention to provide a torque sensing system, a conversion kit with such a torque sensing system, and a vehicle with such a torque sensing system, in which the aforesaid shortcomings are mitigated or at least to provide a useful alternative to the trade and public.

Summary of the Invention

According to a first aspect of the present invention, there is provided a torque sensing system including a deformable substrate fixedly engageable with a vehicle spindle, at least one strain gauge fixedly received on or within a space of said deformable substrate for simultaneous rotation with said deformable substrate and said vehicle spindle about a common longitudinal axis of rotation, and a one-way power transmission mechanism received on or within a space of said deformable substrate for transmitting mechanical power inputted by a rider, wherein an axis substantially perpendicular to a major surface of said strain gauge is substantially parallel to said common longitudinal axis of rotation.

According to a second aspect of the present invention, there is provided a conversion kit for converting a manually-driven vehicle to an electric or power-assisted vehicle, said conversion kit including a torque sensing system including a deformable substrate fixedly engageable with a vehicle spindle, at least one strain gauge fixedly received on or within a space of said deformable substrate for simultaneous rotation with said deformable substrate and said vehicle spindle about a common longitudinal axis of rotation, and a one-way power transmission mechanism received on or within a space of said deformable substrate for transmitting mechanical power inputted by a rider, wherein an axis substantially perpendicular to a major surface of said strain gauge is substantially parallel to said common longitudinal axis of rotation.

According to a third aspect of the present invention, there is provided a vehicle including a torque sensing system and a vehicle spindle, said torque sensing system including a deformable substrate fixedly engaged with said vehicle spindle, at least one strain gauge fixedly engaged on or within a space of said deformable substrate for simultaneous rotation with said deformable substrate and said vehicle spindle about a common longitudinal axis of rotation, and a one-way power transmission mechanism received on or within a space of said deformable substrate for transmitting mechanical power inputted by a rider, wherein an axis substantially perpendicular to a major surface of said strain gauge is substantially parallel to said common longitudinal axis of rotation.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying drawings, in which:

Fig. 1A is a front view of a square-tapered spindle with standard dimensions;

Fig. 1B is front view of an ISIS standard spline spindle with standard dimensions;

Fig. 2 is a bicycle including a torque sensing system according to an embodiment of the present invention;

Fig. 3 is a longitudinal sectional view of the torque sensing system shown in Fig. 2;

Fig. 4 is a partial perspective sectional view of the torque sensing system shown in Fig. 3;

Fig. 5 is a perspective exploded view of a part of the torque sensing system shown in Fig. 4;

Fig. 6 is a perspective exploded sectional view of the part of the torque sensing system shown in Fig. 5;

Fig. 7 is a longitudinal sectional view of the part of the torque sensing system shown in Fig. 5 as assembled;

Fig. 8 is a perspective sectional view of the torque sensing system shown in Fig. 7;

Fig. 9 is a longitudinal sectional view of the torque sensing system shown in Fig. 7, showing also its connection with the bicycle drive sprocket;

Fig. 10 is a schematic diagram showing transmission of mechanical power from a rider through various parts of a bicycle with the torque sensing system shown in Fig. 2;

Fig. 11 is a partial perspective exploded view of a part of the torque sensing system shown in Fig. 5;

Fig. 12 is a perspective view of the part of the torque sensing system shown in Fig. 11;

Fig. 13A is a perspective exploded view of the part of the torque sensing system shown in Fig. 12;

Fig. 13B is a schematic view of the part of the torque sensing system shown in Fig. 13A;

Fig. 14 is a longitudinal sectional view of the part of the torque sensing system shown in Fig. 12;

Fig. 15 is a perspective view of the deformable substrate in the torque sensing system shown in Fig. 3;

Fig. 16 is a schematic perspective view of the Hall-effect sensing system in the torque sensing system shown in Fig. 3;

Fig. 17 is an exploded sectional view of a part of the torque sensing system shown in Fig. 3;

Fig. 18 is a perspective exploded sectional view of the part of the torque sensing system shown in Fig. 17;

Fig. 19 is another perspective sectional view of the torque sensing system shown in Fig. 3;

Fig. 20 is a perspective sectional view of a torque sensing system according to a further embodiment of the present invention;

Figs. 21 and 22 show the principles of operation of the torque sensing system according to the present invention.

Detailed Description of the Embodiments

Fig. 2 shows a bicycle (generally designated as 100) including a torque sensing system (generally designated as 50) according to an embodiment of the present invention. The pedals and cranks of the bicycle 100 are removed for clarity purposes. The bicycle 100 may be exclusively motor-driven (i.e. with no mechanism for allowing input of pedalling power by a rider) or power-assisted (i.e. power may be inputted by the rider pedalling the pedals and by a motor, as necessary or selected by the rider) . In addition, the bicycle may be manufactured ex-factory as exclusively motor-driven or power-assisted, or may be manufactured ex-factory as an exclusively manually-driven bicycle, but is retrofitted as an exclusively motor-driven or power-assisted bicycle by installation of a conversion kit including the torque sensing system 50.

Figs. 3 to 19 show various views of the torque sensing system 50. Generally speaking, the torque sensing system 50 includes the following components:

- a deformable substrate (which may be made of a metal, a metal alloy, acomposite material or a combination of these materials) , such as a steel workpiece 1, having a cylindrical body 20 with a relatively large cylindrical surface for mating with a one-way clutch (to be discussed below) , a central longitudinal cylindrical shaft 22 with an outer shaft surface for mounting bearing (to be discussed below) , a number of openings 24, and an inner space 26 between the inner circumferential surface of the cylindrical body 20 and the central longitudinal shaft 22, and with a central longitudinal axis of rotation r ₁-r ₁,

- a bicycle central shaft (or bicycle central spindle) 2 with an outer diameter at or adjacent the location where the spindle 2 joins the crank being at least 20 mm, e.g. more than 21 mm,

- a one-way clutch 3,

- a rotational power transmission component 4, which may be a gear, a sprocket or a pulley,

- a strain gauge 5,

- a stationary data and power processing unit 6 provided with an antenna,

- a rotatable data and power processing unit 7 provided with an antenna,

- a magnet ring 8 having a number of equi-angularly disposed alternatively oppositely oriented magnets 28, and with a central longitudinal axis of rotation r ₂-r ₂,

- a Hall-effect sensor 30 operatively associated with the magnet ring 8,

- a spindle bearing 9,

- a torque sensor module bearing 10,

- a rotational power transmission component bearing 11,

- a motor body 12 for housing a motor (e.g. an electric motor) and various components, including a set of gears connecting and between the electric motor and the bicycle sprocket 15, and a controller unit to receive torque-related signals for determining and controlling the motor power output,

- a rotatable power transceiving metal coil 13, and

- a stationary power transceiving metal coil 14.

When the above components are duly assembled, as shown in Figs. 3, 4, 7 and 8:

(1) the steel workpiece 1, the one-way clutch 3, the rotational power transmission component 4, the stationary data and power processing unit 6, the rotatable data and power processing unit 7, the magnet ring 8, the spindle bearing 9, the torque sensor module bearing 10, the rotational power transmission component bearing 11, the rotatable power transceiving metal coil 13, and the stationary power transceiving metal coil 14 are positioned co-axially around the bicycle spindle 2;

(2) the steel workpiece 1, the bicycle spindle 2, the strain gauge 5, the rotatable data and power processing unit 7, the magnet ring 8, and the rotatable power transceiving metal coil 13 are fixedly engaged with one another for simultaneous rotation about a common axis of rotation R-R;

(3) the central longitudinal axis of rotation r ₁-r ₁ of the steel workpiece 1 and the central longitudinal axis of rotation r ₂-r ₂ of the magnet ring 8 coincide with the common axis of rotation R-R;

(4) the stationary data and power processing unit 6 and the rotatable data and power processing unit 7 are in a power-transmissible relationship with each other via non-contact interaction between the rotatable power transceiving metal coil 13 and the stationarypower transceiving metal coil 14;

(5) each of the stationary data and power processing unit 6 and the rotatable data and power processing unit 7 is provided with a respective antenna, and the stationary data and power processing unit 6 and the rotatable data and power processing unit 7 are in a signal-communicable (and thus data-communicable) relationship with each other via non-contact interaction through the antennae;

(6) the rotatable data and power processing unit 7 and the rotatable power transceiving metal coil 13 are on one side of the steel workpiece 1 and the stationary data and power processing unit 6 and the stationary power transceiving metal coil 14 are on the opposite side of the steel workpiece 1 (and thus installed in the motor body 12) ; and

(7) an axis r ₃-r ₃ perpendicular to a major planar surface 32 of the strain gauge 5 is offset relative to and parallel to the common axis of rotation R-R. This feature is shown more clearly in Fig. 13B.

As shown in Fig. 9, when the torque sensing system 50 is installed in a bicycle (e.g. the bicycle 100) , the spindle 2 is engaged with the steel workpiece 1 through a set of splines. The steel workpiece 1 is then connected to the rotational power transmission component 4 via the one-way clutch 3. The rotational power transmission component 4 is then rigidly connected to a bicycle drive sprocket 15 (or a bicycle pulley) , which is eventually connected with the drive wheel of the bicycle 100. Conceptually, and as shown in Fig. 10, the mechanical power inputted by a rider upon pendalling of pedals of the bicycle 100 is transmitted, successively, through the spindle 2, the steel workpiece 1, the one-way clutch 3, the rotational power transmission component 4, to the bicycle drive sprocket 15. In this connection, the rotational power transmission component 4 is part of a drivetrain in the motor system, and the drivetrain may be a set of gears, pulleys or sprockets which connect the bicycle sprocket and the electric motor unit.

As shown in Figs. 11 to 15, the strain gauge 5, the rotatable data and power processing unit 7, the magnet ring 8 and the rotatable power transceiving metal coil 13 are all received within the space 26 of the steel workpiece 1 for simultaneous rotational movement about the common axis of rotation R-R. The strain gauge 5, the rotatable data and power processing unit 7 and the magnet ring 8 are stacked one on another within the space 26 of the steel workpiece 1. More particularly, the strain gauge 5 is fixedly received within one of the several openings 24 in the steel workpiece 1. As there are several openings 24 in the steel workpiece 1, it is possible to provide more than one strain gauge 5, so as to enhance the accuracy and sensitivity of torque measurement.

It can be seen from the above that the strain gauge 5 is out of contact with the bicycle spindle 2. In this arrangement, the strain gauge 5 is to measure radial deformation of the steel workpiece 1 caused by deformation of the bicycle spindle 2 resulting from the application of a torque to the vehicle spindle 2 (e.g. upon pedalling of the pedals by a rider) , and to generate torque-related signals representing the torque applied on the bicycle spindle 2.

The torque sensing system 50 includes at least one Hall-effect sensing system including the Hall-effect sensor 30 and the magnet ring 8. Rotation of the cranks will bring about simultaneous rotation of the bicycle spindle 12 and the magnet ring 30. Upon rotation of the magnet ring 8, the Hall-effect sensor 30 will detect fluctuation of the magnetic field, to thereby measure the speed of rotation of the magnet ring 8, and thus that of the bicycle spindle 2, so as to generate spindle rotational speed signals (also called “cadence signals” ) . Another kind of sensors for measuring the speed of rotation of the bicycle spindle 12 and generating cadence signals may be an optical encoder. Briefly stated, an optical encoder includes a slotted disk fixedly and coaxially engaged with the bicycle spindle 12 for simultaneous rotation about the common axis of rotation R-R. The frequency of the flashing light from a light source on a side of the slotted disk is detected by a light detector on an opposite side of the slotted disk, for determining the rotational speed of the slotted disk, and thus that of the bicycle spindle 12, for generating the cadence-signals of the vehicle spindle 2.

The stationary data and power processing unit 6 and the stationary power transceiving metal coil 14 are engaged with the other parts of the bicycle 100 so as to be stationary relative to the structure of the bicycle 200. For example, as shown in Fig. 19, the stationary data and power processing unit 6 and the stationary power transceiving metal coil 14 are fixed to a rigid stationary face of the motor body 12, which also houses (amongst other parts) an electric motor and a gearbox (connected between the electric motor and the sprocket) , suitable for installation on an existing bicycle.

The mechanical output of the torque sensing system 50 is connected with the rotational power transmission component 4 via the one-way clutch 3. The rotational power transmission component 4 may be a gear, a sprocket or a pulley. As shown in Fig. 20, the electric motor unit is installed in a front large circular bracket, and the rotational power transmission component 4 is driven by a chain connected to the electric motor unit. It can be seen that the one-way clutch 3 is received within a space of the steel workpiece 1. This assists in yielding a small product form factor. Alternatively, the torque sensing system 50 may be implemented in the centre of the bicycle sprocket set, where the motor is connected to the bicycle sprocket set through another set of chain and sprocket, instead of a gear mechanism.

The one-way clutch 3 is used for connecting the bicycle spindle 2 and the rotational power transmission component 4 (which is fixedly connected with the bicycle sprocket) in one direction. When the rider pedals, the bicycle spindle 2 will rotate in a forward direction and thus engages the one-way clutch 3 through the torque sensing system 50. The one-way clutch 3 prevents rotation of the bicycle pedals when the rotational power transmission component 4 receives power from the motor, and combines the power from the motor in the motor body 12 and human power inputted by the rider through pedalling the pedals when the system is in a “pedal assist mode. ”

In operation, and as shown in Fig. 21, when a rider pedals the bicycle 100 with the torque sensing system 50, a pedalling force is generated 202, which causes the bicycle spindle 2 to rotate 204. Rotation 204 of the bicycle spindle 2 brings about corresponding simultaneous rotation of the relevant parts of the torque sensing system 50, including rotation 206 of the magnet ring 8. The fluctuation of the magnetic field caused by rotation of the magnet ring 8 is detected by the Hall-effect sensor 30, which in turn produces cadence signals 208 representing the rotational speed of the bicycle spindle 2, on the basis of which the then current speed of the bicycle 100 may be deduced. The cadence signals are fed to a motor main controller 210, which determines the motor power output partly on the basis of the cadence signals 212.

Simultaneously, the pedalling force causes deformation of the bicycle spindle 2, and thus deformation 214 of the steel workpiece 1 of the torque sensing system 50, which is measured by the strain gauge 5, whereby torque-related signals are generated 216. The torque-related signals (which relate to the force exerted on the cranks) are fed to the motor main controller 218, which determines the motor power output partly on the basis of the torque-related signals 220.

At the same time, rotation 204 of the bicycle spindle 2 will bring about rotation of the torque sensing system 50 through engagement 222 with the one-way clutch 3. The rotational power transmission component 4 will be caused to rotate 224, thus propelling 226 the bicycle 100.

As discussed above, on the basis of at least the cadence signals and the torque-related signals, the motor main controller will determine whether to activate the motor to provide power, and, if so, how much power, to assist the rider to drive the bicycle 100.

Turning to Fig. 22, such shows the control schematic logic of the torque sensing system 50. The electrical and/or electronic components of the torque sensing system 50 are powered by an electric power, e.g. a DC voltage input 300. The power is transmitted by a power supply management chip 302 in the stationary data and power processing unit 6 to a power supply management chip 304 in the rotatable data and power processing unit 7, via non-contact interaction between the stationary power transceiving metal coil 14 on the stationary data and power processing unit 6 and the rotatable power transceiving metal coil 13 on the rotatable data and power processing unit 7. The power thus received by the rotatable data and power processing unit 7 is used for powering the strain gauge 5, a strain gauge amplifier 306, and a micro-processor 308 for receiving torque-related signals from the strain gauge 5 for subsequent transmission.

Fluctuation in magnetic field caused by rotation of the magnet ring 8 is detected and measured by the Hall-effect sensor 30 to generate cadence signals representing pedalling rotational speed 310.

Electrical power is transmitted between the stationary data and power processing unit 6 and the rotatable data and power processing unit 7 via non-contact interaction between the rotatable power transceiving metal coil 13 on the rotatable data and power processing unit 7 and the stationary power transceiving metal coil 14 on the stationary data and power processing unit 6. Torque-related signals are transmitted by the rotatable data and power processing unit 7 to a micro-processor 312 in the stationary data and power processing unit 6, via non-contact interaction between an antenna on the rotatable data and power processing unit 7 and an antenna on the stationary data and power processing unit 6. The torque-related signals received by the micro-processor 312 represent pedalling force 314 acted on the cranks. The cadence signal output and torque signal output are transmitted to the motor main controller to control operation of the motor and motor power output 316, in particular to determine whether the motor should be activated to provide additional power to the bicycle 100 and, if so, how much power should be provided.

It can be seen from the foregoing that the present invention has at least the following advantages:

(1) such presents a low-cost, compact, adaptable and structurally sound torque sensing system 50 for an electric bicycle, such as an electric mid-drive bicycle system;

(2) a number of essential components (including the strain gauge 5, the rotatable data and power processing unit 7, the rotatable power transceiving metal coil 13, and the magnet ring 8) are all assembled within the inner space of a steel workpiece 1, thus resulting in a more compact arrangement;

(3) space on the outer circumferential surface of the bicycle spindle 2 is freed up, allowing for the adoption of a bicycle spindle 2 of a higher strength;

(4) a sprag-type one-way bearing, which is far superior to the ratchet-type one-way bearing used in other motor systems, may be used in conjunction with the present invention;

(5) unlike some other strain-gauge type torque measuring system, in the present invention, deformation signals measured by the strain gauge 5 are purely induced by torsional deformation of the bicycle spindle 2, as any bending deformation of the bicycle spindle 2 will not be transferred to the strain gauge 5;

(6) the steel workpiece 1 also serves to house such other mechanical components as the one-way clutch 3, the rotational power transmission component 4, and the torque sensor bearing 10; and

(7) an integrated design of the torque sensing system combining the installation of the above major electrical, electronic and mechanical components into a compact part simplifies the mechanical design of the motor system.

It should be understood that the above only illustrates example whereby the present invention may be carried out, and that various modifications and/or alterations may be made thereto without departing from the spirit of the invention.

It should also be understood that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any appropriate sub-combinations.

Claims

A torque sensing system including:

a deformable substrate fixedly engageable with a vehicle spindle,

at least one strain gauge fixedly received on or within a space of said deformable substrate for simultaneous rotation with said deformable substrate and said vehicle spindle about a common longitudinal axis of rotation, and

a one-way power transmission mechanism received on or within a space of said deformable substrate for transmitting mechanical power inputted by a rider,

wherein an axis substantially perpendicular to a major surface of said strain gauge is substantially parallel to said common longitudinal axis of rotation.
A torque sensing system according to Claim 1, wherein said deformable substrate is made of a metal, a metal alloy, a composite material, or a combination thereof.
A torque sensing system according to Claim 1 or 2, wherein that said strain gauge is fixedly received in an opening of said deformable substrate.
A torque sensing system according to any of the preceding claims, wherein said strain gauge is adapted to measure deformation of said deformable substrate caused by the input torque of said vehicle spindle resulting from the application of a torque to said vehicle spindle and to generate torque-related signals representing torque applied on said vehicle spindle.
A torque sensing system according to any of the preceding claims, wherein a first data and power processing unit is fixedly engaged on or within said space of said deformable substrate.
A torque sensing system according to any of the preceding claims, further including a detector for detecting the speed of rotation of said vehicle spindle about said common longitudinal axis of rotation and generating cadence-related signals of said vehicle spindle.
A torque sensing system according to Claim 6, wherein said detector includes a magnet ring member with at least two oppositely oriented magnets fixedly engaged on or within said space of said deformable substrate.
A torque sensing system according to Claim 7, wherein said magnet ring member is simultaneously rotatable with said vehicle spindle about said common longitudinal axis of rotation.
A torque sensing system according to Claim 7 or 8, further including a Hall-effect sensor for detecting the speed of rotation of said magnet ring member about said common longitudinal axis of rotation and generating said cadence-related signals.
A torque sensing system according to any one of Claims 1 to 6, wherein said detector includes an optical encoder.
A torque sensing system according to any of the preceding claims,

wherein said deformable substrate has a substantially cylindrical body and a central longitudinal shaft member, and

wherein said strain gauge is adapted to measure radial deformation of said deformable substrate.
A torque sensing system according to any of the preceding claims, wherein said strain gauge, said first data and power processing unit and said magnet ring member are received within said space of said deformable substrate.
A torque sensing system according to Claim 12, wherein said strain gauge, said first data and power processing unit and said magnet ring member are stacked one on another within said space of said deformable substrate.
A torque sensing system according to any of the preceding claims, wherein a first metal coil is received within said space of said deformable substrate.
A torque sensing system according to any of the preceding claims, further including a second data and power processing unit in a non-contact signal-communicable and power-transmissible relationship with said first data and power processing unit.
A torque sensing system according to Claim 14 or 15, further including a second metal coil member operatively associated with said first metal coil member for allowing non-contact power transmission between said first data and power processing unit and said second data and power processing unit.
A torque sensing system according to any one of Claims 14 to 16, wherein said second data and power processing unit and said second metal coil member are fixedly engaged with a motor housing.
A torque sensing system according to any one of Claims 14 to 17, further including a third data processing unit for processing torque-related signals received from said second data and power processing unit and said cadence-related signals received from said detector.
A torque sensing system according to any one of Claims 15 to 18,

wherein said first data and power processing unit includes a first antenna,

wherein said second data and power processing unit includes a second antenna, and

wherein said first data and power processing unit and said second data and power processing unit are in a non-contact signal-communicable relationship with each other through said first antenna and said second antenna.
A torque sensing system according to any of the preceding claims, wherein the outer diameter of the vehicle spindle at or adjacent the location where the vehicle spindle joins the crank is at least 20 mm.
A conversion kit for converting a manually-driven vehicle to an electric or power-assisted vehicle, said conversion kit including a torque sensing system according to Claim 1.
A vehicle including a torque sensing system according to Claim 1.
A vehicle according to Claim 22, wherein an output of said torque sensing system is connected with a rotational power transmission component via said one-way power transmission mechanism.
A vehicle according to Claim 23, wherein said rotational power transmission component comprises a gear, a sprocket or a pulley.