Drive arrangement and method for a human-powered vehicle

Abstract

A drive device for an HPV including and propelled by a crank assembly, the device comprising: a housing attachable to the HPV; a motor carried by the housing; and a drive wheel located within the housing and connectable to and driven by the motor, the drive wheel being attachable to the crank assembly for rotation therewith, the drive wheel having an opening extending through its center and accessible from an opposite side of the housing, thereby allowing a crank on the HPV to pass through the opening for mounting to the drive wheel.

Description

Technical Field

[0001] This invention relates to a human-powered vehicle (HPV) whose propulsion can be enhanced by an auxiliary source, such as an electric motor. The HPV may be a bicycle. Background Technology

[0002] HPVs are vehicles whose movement can be at least partially powered by the vehicle's occupants or riders. An increasing number of HPVs are equipped with auxiliary drive systems.

[0003] To provide assistance to HPVs (such as bicycles), an electric motor can be incorporated to provide additional power. This can be helpful, for example, when cycling uphill. Some systems can propel the bicycle even when the rider is not pedaling. Other systems provide power to the bicycle when the rider is pedaling. The latter type of bicycle is sometimes referred to as a "pedal-assisted" electric bicycle.

[0004] There are several ways to provide auxiliary drive to a bicycle and thus assist the rider using power from an electric motor. For example, drive can be provided directly to the wheels (e.g., by using specially designed wheels), or drive can be provided to the bicycle's cranks. The latter system tends to be positioned around the bicycle's crankset and is sometimes referred to as a "mid-drive" auxiliary unit.

[0005] Some mid-drive auxiliary units are integrated into the bicycle. For example, a bicycle can be manufactured to include a mid-drive auxiliary unit that is not removable during normal service. Other mid-drive auxiliary units can be attached to a standard bicycle to upgrade it to a mid-drive bicycle. Attaching such a mid-drive unit is often complex and requires skills and tools that the average cyclist may not possess. Furthermore, once the mid-drive auxiliary unit is installed, removing it from the bicycle to restore it to its original state is usually not straightforward. This is often because the bicycle must be adapted to accommodate the mid-drive auxiliary unit, for example, by replacing the chain set with an alternative chain set. This makes converting a bicycle from a mid-drive bicycle to a non-mid-drive bicycle more difficult.

[0006] Some mid-drive assist units are equipped with a mechanism that allows riders to pedal slower than the output that turns the wheel (e.g., the chain and chain links). Such mechanisms are typically in the form of a one-way clutch or a freewheel, which are subjected to high stress and are bulky, large, and expensive.

[0007] There is a need for a mid-drive assist unit that is not bulky and heavy, unlike some other types of assist units. There is a need for a mid-drive assist unit that can be easily removed from the bicycle when not needed. There is a need for a mid-drive assist unit in which motor assistance functions can be isolated, for example, when the battery is depleted or if the rider wishes to ride without assistance, without feeling any drag from the motor. It is also desirable to measure the force applied by the rider to the pedals, which can be used to control the assist unit. It is also desirable to achieve the above without excessively increasing the bicycle's stance width (the distance between the two pedals). Summary of the Invention

[0008] According to one aspect, a drive device for an HPV is provided. The HPV includes a crank assembly. The HPV is propelled by the crank assembly. The drive device includes: a housing attachable to the HPV; a motor carried by the housing; and a drive wheel located within the housing and connectable to and driven by the motor. The drive wheel is attachable to the crank assembly for rotation therewith. The drive wheel has an opening extending through its center, the opening being accessible from an opposite side of the housing, thereby allowing a crank on the HPV to pass through the opening for mounting to the drive wheel.

[0009] The drive wheel can be captured within the housing in such a way that it can float radially relative to the housing.

[0010] The housing may include an internal formation for engaging the drive wheel to keep the drive wheel engaged in a position where it can be accessed from opposite sides of the housing through an opening.

[0011] The internal molding structure can be configured to engage the outer edge of the drive wheel.

[0012] The drive wheel may have a first annular structure extending axially. The internal molding structure includes a second annular structure, which is located radially inside or radially outside the first annular structure.

[0013] The second annular structure may be located radially inside the first annular structure. The internal molding structure may include a third annular structure located radially outside the first annular structure.

[0014] The internal molding structure may consist only of the second annular structure located radially inside the first annular structure.

[0015] The housing can surround the drive wheel around its circumference.

[0016] The housing may extend only partially around the circumference of the drive wheel.

[0017] The drive unit may also include a drive belt for connecting the drive wheel to the motor.

[0018] The drive wheel may include a rim and a plurality of lobes extending radially inward from the rim. Each lobe may include a securing formation, thereby enabling the drive wheel to be directly or indirectly secured to a crank on the HPV.

[0019] The drive wheel may include one or more through holes, thereby enabling the drive wheel to be fastened to a crank on the HPV.

[0020] The drive unit may be provided together with an HPV including a pedal, wherein the opening of the drive wheel is shaped to allow the pedal of the HPV to pass through the opening.

[0021] The housing may include a plurality of first mounting structures, thereby enabling the housing to be mounted to the HPV, and at least one of these mounting structures has an electrical conductor that, when the drive unit is connected to the HPV, contacts an electrical conductor on the HPV for transmitting power between the HPV and the drive unit.

[0022] The drive unit may be provided together with the HPV, the housing of the drive unit including a plurality of first mounting structures, and the HPV including a plurality of second mounting structures. The first and second mounting structures may be configured such that when the drive unit is mounted to the HPV and each of the first mounting structures engages with a corresponding one of the second mounting structures, the drive wheel can be positioned such that the bottom-bracket axis of the HPV extends through the center of the drive wheel.

[0023] The HPV may have a structural frame including the second mounting structure. The drive unit may be configured such that when each of the first mounting structures engages with a corresponding one of the second mounting structures and the drive wheel is positioned such that the central axis of the HPV extends through the center of the drive wheel, the motor of the drive unit is positioned closer to the midplane of the frame than the drive wheel.

[0024] At least one of the first mounting structures may be located radially outside the outer edge of the drive wheel.

[0025] At least one of the first mounting structures may be located radially inward of the outer edge of the drive wheel. The drive wheel may define an access port positioned such that, when the center of the drive wheel is located on the central axis of the HPV, it is possible to enter one of the first mounting structures through the port in a direction parallel to the central axis for securing the drive device to the HPV.

[0026] The drive unit can be mounted to the HPV for driving its movement. The HPV may have wheels for engaging a power transmission element, the wheels being mounted around the central axis on the drive side of the HPV, and the power transmission element connecting the wheels to the road wheels of the HPV. The drive wheels may be located on the side of the HPV opposite to the drive side.

[0027] The drive unit may further include a drive belt that connects the drive wheel to the motor. The drive belt may have a bias to employ a curve with a radius larger than that of the drive wheel when tension is released.

[0028] The driving device may further include: A tensioner, operable to apply tension to the belt and operable to release tension from the belt; and A guide member for constraining the belt to the outside of the drive wheel along the path along which the belt disengages from the drive wheel.

[0029] The drive unit can be provided together with the central shaft assembly.

[0030] The central axis assembly may include: A hollow sleeve, which carries multiple bearings within its bore to support a bottom-bracket axle that can rotate within the bearings, the sleeve being mountable to the frame of the HPV. A first mounting structure for the sleeve has elastic resistance to rotation of the sleeve in yaw and roll relative to the frame of the HPV, the elastic resistance being insufficient on its own to prevent the rotation when the central shaft is subjected to unbalanced lateral forces around the first mounting structure, such that the first mounting structure provides a fulcrum for the rotation of the sleeve. A second mounting structure, which, when the sleeve is mounted to the frame of the HPV, is axially displaced from the first mounting structure, and the second mounting structure has compliant drag on the sleeve's rotation in yaw and roll; and One or more sensors are configured to sense radial displacement of the sleeve caused by the rotation of the sleeve about the fulcrum.

[0031] A method is provided for attaching the drive unit to an HPV including a crank to which it is attached, the method comprising: While the crank remains attached to the HPV, the opening of the drive wheel is fitted over the crank; and subsequently, Secure the drive wheel to the crank.

[0032] The crank can carry the pedal, and the method includes performing a looping step while the pedal is held to be carried by the crank.

[0033] The overlay step includes: tilting the drive unit relative to the HPV and translating the drive unit along the crank.

[0034] The motor may have a rotor and a motor output pulley. The drive belt can connect the motor output pulley to the drive pulley to deliver torque from the motor to the drive pulley.

[0035] The drive unit may further include a one-way clutch configured to engage when the rotor of the motor rotates at an engagement speed and disengage when the rotor rotates at a speed lower than the engagement speed. The engagement speed may be a predefined multiple of the rotational speed of the central shaft assembly. The one-way clutch may be located in a drivetrain located between the rotor and the drive wheel.

[0036] The drive unit may further include a controller configured to receive data from one or more sensors. The controller may be configured to use the data from the one or more sensors to determine the torque level that the motor will apply to the rotor. The controller may be configured to control the motor in the HPV's drive state to apply the determined torque level to the rotor.

[0037] The features of the drive unit described under the title "Quick Unbolt" can be combined with any of the features described under the title "Quick Isolation," and / or with any of the features described under the title "Cadre Drop," and / or with any of the features described under the title "Floating Sleeve." The features of the drive unit described under the title "Quick Isolation" can be combined with any of the features described under the titles "Quick Removal" and / or "Cadre Drop" and / or "Floating Sleeve." The features of the drive unit described under the title "Cadre Drop" can be combined with any of the features described under the titles "Quick Removal" and / or "Quick Isolation" and / or "Floating Sleeve." The features of the bottom bracket assembly described under the title "Floating Sleeve" can be combined with any of the features described under the titles "Quick Removal" and / or "Quick Isolation" and / or "Cadre Drop." Attached Figure Description

[0038] The invention will now be described by way of example with reference to the accompanying drawings. In the drawings: Figure 1 An example of a human-powered vehicle in the form of a bicycle is shown.

[0039] Figure 2 It shows attachment to, such as Figure 1 The drive mechanism of a bicycle.

[0040] Figure 3 A cross-section of the drive unit is shown.

[0041] Figures 4a to 4c An example of the internal molded structure of the drive unit housing and the drive wheel is shown.

[0042] Figures 5a to 5e The gradual steps for removing the drive unit from a bicycle are described.

[0043] Figure 6 A method for attaching a drive unit to an HPV is described.

[0044] Figure 7a and Figure 7b A cross-section of the drive unit is shown, depicting the tensioning system in both the untensioned and tensioned states.

[0045] Figure 8 The cross-section of the motor and gearbox of the drive unit is shown.

[0046] Figure 9 A flowchart of an example control algorithm is shown for controlling the speed of a motor in response to data indicating whether motor drive is required.

[0047] Figure 10 A first example shaft assembly including a sleeve is shown in this disclosure.

[0048] Figure 11 It shows Figure 10 Example sensing arrangement of the central axis component.

[0049] Figure 12 A second example shaft assembly including a sleeve is shown in this disclosure.

[0050] Figure 13 It shows Figure 12 Example sensing arrangement of the central axis component.

[0051] Figure 14 A third example shaft assembly including a sleeve is shown in this disclosure.

[0052] Figure 15 It shows Figure 14 Example sensing arrangement of the central axis component.

[0053] Figure 16 It depicts the directions of the bicycle's pitch, yaw, and roll. Detailed Implementation

[0054] Figure 1 An example of a bicycle 100 is shown. The bicycle includes a front wheel 1, a rear wheel 2, and a frame 3. The frame includes a top tube 4, a seat tube 5, a down tube 6, chainstays 7, and top stays 8. Other frame designs are possible. A bottom bracket housing 9 (see, for example) Figure 5a The bottom bracket 10 is located at the junction of the seat tube and downtube. A bottom bracket housing houses the bottom bracket 10. Cranks 11 on either side of the frame are attached to each other via a shaft 12 passing through the bottom bracket housing. The bottom bracket provides bearings by which the shaft is mounted for rotational movement relative to the frame. Pedals 13 are attached to each crank to allow the rider to turn the cranks. On one side of the frame, a chain wheel 14 is attached to this shaft. A chain 15 runs in a circular loop between the chain wheel and a sprocket 16 attached to the rear wheel. This transmits drive from the chain wheel to the rear wheel, enabling the rider to propel the bicycle. The side of the frame where the chain is located is referred to as the drive side, as will be explained in more detail later. The chain can be replaced by other devices for transmitting drive to the rear wheel, such as a ring belt or drive shaft.

[0055] Figure 2 It shows the drive Figure 1 Bicycle drive unit 200. Figure 2 Shown from the side opposite to the side including the sprocket 14 Figure 1 The bicycle. In other words, Figure 2The bicycle is shown from the non-drive side. The drive unit includes a housing 20. The housing can be attached to the bicycle in other ways: for example, to the seatpost and / or to one or more chainstays. The housing houses the motor 22, gearbox 23, drive belt 24, drive wheel 25, and control processor 26 (not shown). The housing 20 is provided with mounting members 21, which can be attached to the frame of the bicycle. The mounting members can be attached to the frame at any suitable location. One convenient approach is to attach mounting member (21a) to the downtube 6 of the bicycle and / or to a structure fastened to the non-drive side of the bicycle's bottom bracket housing, with mounting members (21b) located above and below the drive wheel, respectively. A battery 27 (not shown) for powering the motor can be housed within the housing or mounted in other locations on the bicycle. The control processor controls the operation of the motor in a manner that will be described in more detail below. The motor has a rotor. The rotor drives the input of the gearbox. The output of the gearbox can engage with the drive belt 24, and the drive belt can engage the drive wheel. In this way, the motor can drive the drive wheel to rotate.

[0056] The first significant feature of the drive mechanism is that it does not include an axle around which the drive wheel rotates. Instead, the drive wheel has an opening 28 through its central portion. (For example...) Figure 5c , Figure 5d and Figure 5e The diagram shows the drive unit in its current state, where the drive wheel can float freely relative to the housing, for example, by translating within its main plane. The drive wheel is capable of translating relative to the housing. The drive wheel can be contained within the housing to prevent it from leaving the housing, although it is capable of floating relative to the housing. To achieve this, the housing may define an opening 29 through which the drive wheel enters. The maximum diameter of this opening may be smaller than the outer diameter of the drive wheel. When the drive unit is to be installed... Figure 1 When mounting the bicycle, the pedals and crank on one side of the bicycle pass through the opening 28 in the drive wheel. The drive wheel can then be attached to the crank. The housing is arranged such that when the drive wheel is attached to the crank, the mounting hardware can attach the housing to the bicycle frame. In this configuration, the drive wheel is no longer able to float relative to the housing. The drive wheel is rigidly connected to the crank axle 12 and can rotate about its axis. Since the translational position of the drive wheel is fixed relative to the housing, the drive wheel can then be driven by the belt 24, although the drive wheel does not have an axle extending directly between it and the housing. This provides a convenient way to allow the drive unit to be attached to and removed from the bicycle, as will be further described below.

[0057] The second significant feature is that the drive unit includes a selectively actuated belt tensioner 30. This belt tensioner is movably mounted to the housing. It has a first configuration and a second configuration, in which it is supported on the belt 24 to tension the belt, and in the second configuration, the belt 24 is de-tensioned. The belt tensioner may include an idler pulley 76 that can abut the non-driven portion of the belt. This idler pulley can move between a first position and a second position, in which the belt is tensioned around the drive pulley 25 and the motor-driven wheel 75, and in the second position, the belt is de-tensioned. One way to implement this is to mount the belt tensioner on an arm that pivots relative to the housing. The arm may be actuated by a lever or other means, as will be further described below. The belt has inherent stiffness. In other words, the belt elastically resists being bent to change its natural curvature. Therefore, the belt is inherently biased to adopt a radius larger than the radius of the rim (i.e., outer circumference) of the drive pulley. When the tensioner is actuated to support the belt, it tensions the belt around the gearbox output and drive pulley. In this configuration, the gearbox output and drive wheel are constrained to rotate together at a speed ratio determined by their respective radii. When the tensioner is released to slack the belt, the belt is inherently biased to adopt a larger radius. A guide defines an open channel on the outer side immediately adjacent to the drive wheel. When the tension is released, the belt can extend into this channel, disengaging it from the drive wheel. In this configuration, the drive wheel can rotate independently of the gearbox output. This is convenient because it allows the rider to turn the crank without any connection to the drive unit and allows for a choice between assisted pedaling on the one hand, and unassisted pedaling on the other hand, when the battery is absent or discharged, or when the rider does not want assistance, without any resistance from the drivetrain or motor. This is also convenient because when the drive unit with the first significant feature is being installed on the bicycle, it allows the operator to turn the drive wheel to a position aligned with the crank arm so that the fasteners, mounting holes, etc., on the drive wheel and crank arm are aligned. This makes attaching the drive unit to the bicycle much easier.

[0058] The third notable feature is that, although there is a non-clutch drive path between each crank and chain wheel, there is a one-way clutch 80 located between the motor and the input of gearbox 23. This clutch can be located elsewhere, as will be further described below. The gearbox and belt drive define the drive ratio between the motor and the crankshaft. This gear ratio defines the motor engagement speed for any forward rotational speed of the crank. When the motor (more precisely, the motor's rotor) rotates at this engagement speed, clutch 80 engages, allowing the rotor to deliver torque to the crank. When the rotor rotates forward below this speed or backward above this speed, the clutch slips, and the rotor is unable to deliver torque to the crank. The clutch can be, for example, a ratchet clutch. As will be further described below, control processor 26 receives data from sensors indicating the speed of the crank and the speed of the rotor. The controller implements a control algorithm to control the current applied to the windings, and thus, in response to this data and data indicating whether motor drive is required, controls the torque applied to the rotor. The latter data can be received from a control switch operable by the rider of the HPV and / or (as described further below) from one or more sensors responding to changes in the rider's force on the crank and / or from the output of an algorithm implemented by the controller. When the motor is not driving the crank, the rotor typically rotates at an engagement speed lower than the current speed of the crank. When the controller determines that motor drive is needed, it increases the rotor speed to the engagement speed. This engages the clutch, thereby transferring drive force from the rotor to the crank. When the controller determines that motor drive is no longer needed, it reduces the rotor speed below the engagement speed. This disengages the clutch and stops the motor from driving the crank. Because of the clutch, the controller is able to reduce the rotor speed below the engagement speed in this way without the rider feeling any unwanted deceleration from the pedals, even if the rate of rotor speed reduction exceeds the equivalent rate of cadence reduction.

[0059] A fourth significant feature is provided by the bottom bracket assembly for the HPV, which carries one or more sensors responding to the level of lateral external forces applied to the bottom bracket axle (e.g., due to a rider pressing down on the pedals). In such a bottom bracket assembly, support for the bottom bracket bearing on the non-drive side of the HPV is provided by a compliant, resilient structure, whereby when a radial load in a given direction is borne by this bearing and, consequently, by the compliant structure, there exists a load-dependent bearing displacement that can be detected by sensors. The radial load borne by the non-drive-side bearing in a given plane will be sufficient to balance the moment about the fulcrum, generated by an external radial force applied to the bottom bracket assembly by the rider in the same plane. This fulcrum will tend to be located at the position where the drive-side bearing for the bottom bracket axle is positioned. At any crank angle, there will be a response from one or more sensors to changes in the force induced by the rider. A notable feature of this disclosure is a variation of this arrangement in which the bearing supporting the bottom bracket axle is carried within a rigid sleeve assembly, and it is precisely for this sleeve that a compliant, resilient structure provides support, allowing the entire sleeve, including the bearing and axle, to "float" within a bore in the bicycle's bottom bracket housing. Various ways exist to arrange the support for the sleeve, and the geometry of the drive-side support for the sleeve can be selected such that the fulcrum tends to be located along a specific preferred position on the axle, which in turn affects the level of the balancing radial force provided by the compliant, resilient structure on the non-drive side for a given external lateral force on the bottom bracket assembly. Other advantages, including mechanical simplification, are possible when using such a sleeve to support the bearing.

[0060] Each of the salient features identified above can be implemented independently of any of the other features. One or more of them can be implemented together. The reference to bicycles or tricycles in this document should be understood to apply equally to any HPV.

[0061] Some exemplary arrangements will now be described in more detail.

[0062] Rapid thrombolysis The drive unit disclosed herein is designed for easy attachment and detachment from a bicycle, tricycle, or any other HPV. This provides riders with the flexibility to decide whether to use their bicycle with or without the drive unit. A particularly notable feature of the drive unit 200 is its attachment and detachment from the non-drive side of the HPV. The drive unit is adapted (e.g., through its fixed position on the vehicle) to attach to the non-drive side of the vehicle. The drive unit is adapted (e.g., through the design and placement of its coupling for attachment to the bicycle to transmit drive torque) to apply drive torque to the non-drive side of the bicycle. This type of arrangement avoids the impact on the drive side of the HPV from attaching or detaching the drive unit, or the need for modification to allow for such attachment or detachment. The non-drive side of the HPV is the side that does not include the output device or power transmission element (such as chain assembly and chain or a rotating shaft extending longitudinally relative to the vehicle) used to transmit drive to the road wheels of the vehicle. The non-drive side is typically the left side of the bicycle (when viewed from the rear), but it may not be.

[0063] The HPV includes wheels (e.g., chain wheel 14 or chain link) for engaging a power transmission element. The power transmission element can be a chain 15, a belt, or, in the case of a shaft-driven bicycle, a rigid bar or axle. The wheel is connected to an axle (e.g., a bottom bracket axle) that is capable of rotating in response to input from the rider (e.g., via a pedal connected to a crank, which is connected to and rotates with the axle). The power transmission element (e.g., chain or belt) connects the wheel (e.g., chain link) to the road wheel of the HPV. The road wheel is the wheel of the HPV that contacts the road or ground on which the HPV moves. The wheel (e.g., chain link) is mounted around the bottom bracket axle on one side of the HPV. The side of the HPV on which the wheel is mounted is referred to as the drive side of the HPV. The non-drive side is the side of the HPV opposite the drive side.

[0064] Figure 2 A portion of the HPV is shown from the non-driving side. Figures 5a-5e The side view of the drive unit shown is also from the non-drive side. Figures 5a-5e The image shows a right-side view of the bicycle from the rear, where the bicycle chain links are not shown (but if they were present, they would conventionally be located on the right side).

[0065] Figure 2 The illustrated drive unit 200 includes a housing 20, as mentioned above. The housing is configured to attach to an HPV, for example, a bicycle. The housing may include a plurality of first mounting structures 21. Each of the first mounting structures is coupled to a corresponding mounting element on the HPV, which is referred to as a second mounting structure 53 (see [link to documentation]). Figures 5a-5eAny suitable means (such as bolts and screws) can be used to fasten the first and second mounting structures together. For example, Figure 5a A bolt 54 is shown that fastens one of the first mounting structures 21 to the second mounting structure 53. Figure 5b You can also see bolt 54 being removed from the housing.

[0066] The second mounting structures 53 can be attached to the standard HPV frame in any suitable manner. For example, they can be welded, brazed, bolted, or clamped to the frame, or attached using adhesives. The frame can be manufactured with suitable mounting elements that can be used as the second mounting structure. As an example, Figure 5d The bicycle frame shown includes three second mounting structures 53: one (53a) on the downtube 6 of the bicycle, and two (53b and 53c) carried in the upper and lower arms of a structure respectively fastened to the non-drive side (e.g., the left end) of the bottom bracket housing. The second mounting structures can be located at any suitable position on the frame. Preferred locations for the mounting structures will be described later.

[0067] In the first mounting structure 21, at least one first mounting structure may include an electrical connector (not shown) exposed on a surface of the mounting structure. When the drive unit is connected to the HPV, the surface of the at least one first mounting structure may contact (e.g., abut) a mating surface on the HPV for transmitting power between the HPV and the drive unit. In other words, when the drive unit is attached to the HPV, the surface of the mounting structure may form electrical contact with a portion of the HPV to allow power to be transferred between the drive unit and the HPV. This can be useful for transmitting power from a battery located elsewhere on the HPV or for transmitting control signals for controlling the operation of the drive unit. Examples of such control signals may be signals from sensors mounted to the HPV or signals from rider inputs (such as switches).

[0068] The housing 20 includes a motor 22. The motor may be an electric motor. The motor is supported by the housing. In other words, the housing houses the motor.

[0069] The housing includes a drive wheel 25. The drive wheel is driven by power from a motor. For example, the output from the motor (e.g., the output from a gearbox) can be coupled to the drive wheel via a belt 24. The belt transmits the drive from the motor output to the drive wheel, thereby driving the drive wheel.

[0070] The drive wheel 25 is carried inside the housing. Figure 3A cross-section of the drive unit 200 is shown, in which the drive wheel 25 is visible. When the drive wheel is not connected to the bicycle crank (as explained later), the drive wheel 25 can be loosely accommodated within the housing. In other words, the drive wheel can float freely within the housing (e.g., move around). The drive wheel can move radially relative to the housing (e.g., Figure 3 The drive wheel can float relative to the housing in the axial direction (e.g., the direction of the dashed line R in the diagram). Figure 3 The drive wheel floats in the direction of the dashed line A in the diagram. Therefore, the drive wheel is captured within the housing in such a way that it can float radially relative to the housing when it is not connected to the crank assembly.

[0071] When the drive wheel is attached to the crank, the only device constraining the rotation of the drive wheel relative to the housing can be the attachment of the drive wheel to the crank. When the drive wheel is attached to the crank, the only device constraining the radial and / or axial movement of the drive wheel relative to the housing can be the attachment of the drive wheel to the crank.

[0072] In other words, apart from the connection between the drive wheel and the crank (as will be explained later), there may be no attachment between the drive wheel and the housing to hold the drive wheel in a fixed position relative to the housing. The housing may be arranged such that, when the housing is rigidly attached to the vehicle frame, the action of attaching the drive wheel to the crank causes the drive wheel to be constrained to rotate relative to the housing.

[0073] Therefore, the drive unit can be configured in a first way, wherein the drive wheel is rigidly attached to the crank and the housing is rigidly attached to the vehicle frame. In this configuration, the drive wheel is constrained to rotate relative to the housing due to the fact that the crank is constrained to rotate relative to the housing by the vehicle's bearings. The drive unit can be configured in a second way, wherein the drive wheel is disengaged from the crank. In this configuration, the drive wheel floats freely relative to the housing, or moves radially and / or axially. This behavior is permitted because the drive unit does not have bearings acting between the drive wheel and the housing.

[0074] When the drive wheel is not connected to the crank, it can translate freely radially and / or axially within the housing. This allows the drive wheel to be connected to the crank arm when its center is in multiple positions relative to the housing. In other words, the drive wheel does not need to be in a specific radial and axial position relative to the housing for it to be connected to the crank arm.

[0075] Although the drive wheel can float freely within the housing, the housing includes an internally shaped structure 31 that holds the drive wheel in place so that it does not escape from the housing. For example, the walls of the housing can serve as an internally shaped structure that restricts the axial movement of the drive wheel. Such as Figure 3The internal molding structures 31 shown are used to hold the drive wheel in the radial direction. The internal molding structures also serve to hold the drive wheel in a position where it can be accessed from the opposite side of the housing through an opening.

[0076] The following will refer to Figures 4a to 4c A more detailed description of the internal molding structure.

[0077] The internal forming structure 31 can be configured to engage the outer edge of the drive wheel and / or a portion of the drive wheel inside its outer edge. In the former case, the internal forming structure can be configured to circumferentially engage a portion of the drive wheel. Figure 3 An example is shown in which an internal molding structure 31 is provided to engage a cylindrical flange located at the outer edge of the drive wheel in order to suppress translation of the drive wheel in a direction perpendicular to its axis. The internal molding structure can achieve this function by engaging the inward-facing surface of the drive wheel. The internal molding structure can also achieve this function by engaging the outward-facing surface of the drive wheel.

[0078] The drive wheel may include an axially extending drive wheel annular structure 32. The drive wheel annular structure 32 extends in the direction of the drive wheel's axis (e.g., in the direction of dashed line A). For example, Figure 3 A drive wheel 25 with an axially extending drive wheel annular structure 32 is shown, on which a belt 24 is located. Figure 3 In the example shown, the drive wheel annular structure 32 is located at the outer edge of the drive wheel. When the drive wheel annular structure is located inside the rim of the drive wheel, the belt can be located on the outer surface of the rim of the drive wheel. The drive wheel annular structure 32 does not necessarily have to be located on the outer surface of the rim of the drive wheel. For example, the drive wheel annular structure can be located radially inside the rim of the drive wheel. Figures 4a to 4c An example of a drive wheel annular structure 32 located radially inside the rim of the drive wheel is shown.

[0079] The drive wheel ring structure 32 can be discontinuous. For example, Figure 4c The drive wheel ring structure 32 shown does not extend integrally around the drive wheel. Figure 4c The illustrated drive wheel annular structure 32 includes two components forming an annular structure around the drive wheel. The drive wheel annular structure can be continuous. In other words, the drive wheel annular structure can extend integrally around the drive wheel to form a complete circle. When the drive wheel annular structure is continuous, it can be referred to as a drive wheel ring.

[0080] As mentioned above, the internal molding structure 31 of the housing is used to retain the drive wheel within the housing and to position the drive wheel such that it can be accessed from both sides of the housing through openings. The internal molding structure may include a housing annular structure 31. The housing annular structure may be discontinuous. The housing annular structure 31 may be located radially inside or radially outside the drive wheel annular structure. For example, Figure 4a A housing annular structure 31a is shown located radially inside the drive wheel annular structure 32. The housing annular structure 31 can be located radially outside the drive wheel annular structure 32. Due to the axially extending drive wheel annular structure, each configuration retains the drive wheel 25 to prevent it from escaping from the housing in the radial direction (e.g., in a direction parallel to the dashed line R). In other words, it is sufficient to radially retain the drive wheel using either a housing annular structure located radially outside the drive wheel annular structure or radially inside the drive wheel annular structure. As mentioned above, the sidewalls of the housing 20 can retain the drive wheel to prevent it from escaping from the housing in the axial direction (e.g., in a direction along the dashed line A).

[0081] The internal molding structure may include a housing annular structure located radially inner and radially outer sides of the drive wheel annular structure 32. For example, Figure 4b A first housing annular structure 31a located radially inner to the drive wheel annular structure and a second housing annular structure 31b located radially outer to the drive wheel annular structure are shown. Therefore, the internal molding structure may include both the first and second housing annular structures. The first or second housing annular structure may be discontinuous.

[0082] Figure 4c An example of a first housing annular structure and a second housing annular structure positioned around a drive wheel 25 is shown. The first housing annular structure 31a is located radially inside the drive wheel annular structure 32. The first housing annular structure 31a may be formed by a flange 31a (e.g., a ridge) that provides the inner side of the drive wheel annular structure against its mounting surface. The second housing annular structure may be formed by a pin 31b surrounding the outer side of the drive wheel annular structure. The positions of the pin and flange can vary. Any suitable device can be used instead of the pin, flange, and ridge for the first and second housing annular structures. Figure 4c As shown, the internal molding structure does not need to be positioned around the drive wheel at all times. Figure 4c The first and second shell annular structures shown are discontinuous.

[0083] The drive wheel has an opening 28 through its central portion. As mentioned above, this means that when the drive unit is not attached to the HPV, the drive wheel is not constrained to rotate on a shaft or axle extending through its central axis. The opening of the drive wheel is shaped to allow the HPV's crank to pass through it. The drive wheel may also be shaped to allow the HPV's pedal to pass through it. For example, at least a portion of the opening of the drive wheel may span at least 60 mm in a direction perpendicular to the axis of the drive wheel. The opening 28 is accessible from the opposite side of the housing. This allows the HPV's crank to pass through the opening for mounting the crank to the drive wheel, as will be explained in more detail later.

[0084] The housing may include an opening 29 through which access to an opening 28 of the drive wheel is possible. Each side of the housing may include a corresponding opening, which together form the opening 29 of the housing. In other words, the opening 29 of the housing may be formed by openings on two opposite sides of the housing, through which access to the opening 28 of the drive wheel is possible. The housing may surround the drive wheel around its circumference. For example, Figure 2 The housing shown surrounds the drive wheel around its circumference. When the housing surrounds the drive wheel, it includes a hole through which an opening 28 of the drive wheel can be accessed. In other words, the opening 29 of the housing is a hole. However, the housing does not necessarily completely surround the drive wheel. The housing may only partially extend around the circumference of the drive wheel. For example, a portion of the drive wheel may be exposed. In this case, the opening 29 of the housing may not be a hole. The shape of the housing may allow access to the drive wheel from opposite sides of the housing, without a hole through the housing. For example, one end of the housing may be shaped like a crescent moon.

[0085] The housing may extend to cover at least a portion of the outer side of the drive wheel, at least partially around its circumference. In other words, the housing may at least partially enclose the drive wheel. This helps protect the drive wheel from dirt and reduces the risk of items such as a rider's clothing getting caught in the drive wheel as it rotates.

[0086] Now refer to Figures 5a to 5e Describe the attachment of the housing to the HPV frame and the attachment of the drive wheel to the HPV crank. Figures 5a to 5e This shows a progressive snapshot of the drive being removed from HPV.

[0087] The crank to which the drive wheel is attached can be modified to include attachments to which the drive wheel can be attached. For example, as in Figure 5d or Figure 5e As best viewed in the image, the crank may include an attachment 50. The drive wheel includes one or more fastening moldings 51 to secure the drive wheel to the crank. For example, Figures 5a to 5eFour fastening moldings 51 on the drive wheel are shown, corresponding to four attachments 50 on the crank for attaching the drive wheel to the crank. The fastening moldings can be one or more through holes in the drive wheel. Bolts (not shown) can be used to connect the fastening moldings (e.g., through holes) to the attachments on the crank. Any number of attachments can be present on the crank, and any number of fastening moldings can be present on the drive wheel.

[0088] In one example, the drive wheel may include one or more convex angles extending radially inward from the edge or rim of the drive wheel. The rim of the drive wheel may include the edge of the drive wheel. Each convex angle includes at least one fastening structure. For example, Figures 5a to 5e The drive wheel shown includes two convex angles 52, as in Figure 5d and Figure 5e This is what we see best. In this example, Figures 5a to 5e Each convex corner 52 includes two fastening molding structures 51. Figures 5a to 5d In the middle, the convex angle 52 of the drive wheel is visible. Once the fastening molding structure on each convex angle is fastened to the attachment on the crank, the movement of the drive wheel, and thus the movement of the convex angle, will be transmitted to the movement of the crank, and vice versa.

[0089] As mentioned above, the shell can be attached to the HPV. The HPV includes a structural frame, as described above regarding the bicycle.

[0090] To facilitate attachment of the drive wheel to the crank, the first and second mounting structures are arranged such that, when the drive unit is mounted to the HPV and each of the first mounting structures engages with a corresponding one of the second mounting structures, the drive wheel can be positioned such that the central axis of the HPV extends through the central portion of the drive wheel. As mentioned above, when the drive wheel is not attached to the crank, it floats freely within the housing. Therefore, when the drive unit is initially attached to the HPV, the drive wheel can be located in various positions within the housing. The positioning of the first and second mounting structures ensures that, when each of the first mounting structures is connected to the corresponding second mounting structure, the center of the drive wheel is substantially aligned with the central axis of the HPV.

[0091] When the drive unit is attached to the HPV, the drive unit's motor can be positioned closer to the mid-plane of the HPV frame than the drive wheels. The mid-plane of the HPV frame is the plane that divides the frame in half when viewed from the front. The mid-plane of the frame separates the drive side from the non-drive side of the HPV.

[0092] Some of the first mounting structures 21 shown in the attached figures (e.g., Figure 2The first mounting structure 21b) is located outside the drive wheel. In other words, some of the first mounting structures 21 can be positioned further away from the center of the drive wheel than the radius of the drive wheel. At least one of the first mounting structures can be located outside the outer edge of the drive wheel. It may be desirable to reduce the prominence of the second mounting structures 53b and 53c on the HPV. At least one of the first mounting structures can be located inside the outer edge of the drive wheel. In other words, at least one of the first mounting structures can be located on the housing within the radius of the drive wheel. The drive wheel can define an access port (not shown) positioned such that, when the center of the drive wheel is aligned with the central axis of the HPV, access to one of the first mounting structures can be made through the port in a direction parallel to the central axis. This allows the housing of the drive unit to be secured to the frame of the HPV.

[0093] Now refer to Figure 6 A method for attaching a drive unit to an HPV is described. The HPV includes a crank attached thereto.

[0094] The attachment method can begin at step S601 by fitting the opening 28 of the drive wheel through the crank. This is performed while the crank remains attached to the HPV. Fitting the opening of the drive wheel through the crank can involve translating the drive unit along the crank at step S602. It can also involve tilting the drive unit relative to the HPV at step S603. Steps 602 and 603 can be performed in any order.

[0095] Once the drive wheel has been fitted over the crank, the next step is to fasten the drive wheel to the crank at step S605. To make this easier, it is preferable to fasten the housing to the HPV at step 604 before fastening the drive wheel to the crank. However, steps S604 and S605 can be performed in any order. At step 604, the housing is fastened to the frame of the HPV. For example, the first and second mounting structures described above can be used to fasten the housing to the frame of the HPV. It is preferable to fasten the housing to the HPV before fastening the drive wheel to the crank because the position of the mounting structure aligns the drive wheel opening with the axis of the bottom bracket. Alternatively, it is preferable to fasten the drive wheel to the crank before fastening the housing to the HPV because fastening the drive wheel helps stabilize the housing and / or constrain its position to make fastening easier. At step S605, the drive wheel is fastened to the crank. This step may include fastening the drive wheel to rotate relative to the housing by attaching it to the crank. This can be accomplished by using the fastening molding structure 51 of the drive wheel to fasten the attachment 50 to the crank of the HPV, as described above.

[0096] It may be necessary to manually rotate and move the crank or drive wheel until the fastening molding structure 51 of the drive wheel is aligned with the attachment 50 on the crank. As will be explained in more detail later, due to the actuation of the tensioner, the belt 24 can disengage from the drive wheel while the drive unit is being attached to the bicycle, leaving the belt in a de-tensioned state. This allows the drive wheel to rotate independently of the belt and the motor output, making it easier to attach the drive wheel to the crank. The internal molding structure 31 of the housing described above (which prevents the drive wheel from escaping from the housing) and the positioning of the first and second mounting structures also facilitate the attachment of the drive wheel to the crank. When steps S604 and S605 have been completed, the drive wheel is no longer floating freely relative to the housing.

[0097] As mentioned above, the opening of the drive wheel can be large enough for the pedal to pass through for installation. Alternatively, the method may include, at step S600, fitting the opening 28 of the drive wheel through the pedal while the pedal remains attached to the crank. This means that the pedal does not need to be removed from the crank while the drive unit is being attached to the bicycle.

[0098] Figures 5a to 5e The disassembly process for removing the drive unit from HPV is described. This disassembly process follows the steps outlined above and... Figure 6 The steps described herein, but in reverse order. For example, the disassembly process begins at step S610 by removing the drive wheel from the crank. Then, at step S611, the housing is removed from the HPV, as... Figure 5b As shown in the diagram. For example, bolt 54 is removed from the first mounting structure and the second mounting structure to detach the housing from the HPV frame, as shown in the diagram. Figure 5b As shown in the diagram. Steps S610 and S611 can be performed in any order. Now, at step S612, the drive unit can be tilted relative to the HPV frame, as shown. Figure 5c As shown in the diagram. Then, at step S613, the drive unit can be translated along the crank, as shown in the diagram. Figure 5d As shown in the diagram. Then, at step S614, the drive unit is moved over the crank, and optionally over the pedal at step S615, as shown in the diagram. Figures 5d to 5e As shown in the diagram. This removes the drive unit from HPV.

[0099] Therefore, this disclosure provides an auxiliary unit (drive unit) that is easy to attach to and remove from a bicycle. The auxiliary unit of this application does not require a lengthy process or special tools to attach or remove from a bicycle. It also does not interfere with the chain side of the bicycle. Therefore, the auxiliary unit of this disclosure gives riders the flexibility to upgrade their bicycle to an auxiliary bicycle (e.g., if going for hill riding) or to remove the auxiliary unit entirely (e.g., to make the bicycle lighter, or for training or exercise purposes).

[0100] rapid isolation Figure 7a and Figure 7b The illustrated arrangement shows an exemplary mechanism for easily disengaging the motor's auxiliary function so that the user can power a human-powered vehicle without assistance when needed, without feeling any additional resistance from the drive unit.

[0101] As mentioned above, the drive mechanism includes a selectively actuated belt tensioner, which in Figure 7a and Figure 7b The overall shape is shown as 30. The tensioner is movably mounted to the housing 20.

[0102] A tensioner is used to switch the belt between a tensioned state and a de-tensioned state. The tensioner is operable to apply tension to the belt and to release tension from the belt. Figure 7a This indicates the state of being untensioned. Figure 7b The tensioned state is shown. In the untensioned state, a reduced tension force can be applied to the belt. In the untensioned state, the belt can be in compression.

[0103] The belt 24 may be wound around a portion housed within the housing, such as drive wheel 25, wheel 75, and wheel 76. Wheel 25, wheel 75, and wheel 76 may be, for example, pulleys.

[0104] The motor is carried by a housing. The motor is configured to drive wheel 75 to rotate. The motor's output shaft is connected to a gearbox. The gearbox includes wheel 75 and may also include additional gears located between wheel 75 and the motor's output shaft. The motor causes wheel 75 to rotate about an axis parallel to the central shaft. Wheel 75 contacts belt 24. When wheel 75 is driven to rotate by the motor, belt 24 is driven to move. When the belt is tensioned, drive wheel 25 within the housing is driven to rotate by belt 24, and when the drive unit is attached to the HPV, drive wheel 25 within the housing provides drive to the HPV. Figure 7a and Figure 7b In the example shown, there is no relative movement between the respective axes of rotation of wheel 75 and drive wheel 25.

[0105] The belt 24 also wraps around the wheel 76. The wheel 76 may be toothless. The axis of rotation of the wheel 76 is parallel to but offset from the axis of rotation of the wheel 75. The respective axes of rotation of the wheels 75 and 76 are parallel to but offset from the axis of rotation of the drive wheel 25.

[0106] exist Figure 7a and Figure 7bIn the example shown, wheel 76 is an idler pulley. This idler pulley provides tension to the drive belt and guides the drive belt, as will be described in more detail below. The idler pulley can rotate in response to the movement of the belt, but it is not driven by a motor itself.

[0107] Therefore, when the belt is tensioned, the drive belt 24 connects the drive pulley 25 to the motor. The output torque from the motor is transmitted to the drive pulley 25 via the belt 24. Figure 7a and Figure 7b In the example shown, the drive belt is a toothed belt. The teeth may be evenly spaced along the length of the belt. The teeth of the belt engage with corresponding teeth on the drive pulley 25 and on the wheel 75 driven to rotate by the output shaft of the motor. The belt may have other forms. The belt may have teeth only on one side. This may be the side of the belt that contacts the drive pulley 25. The toothed side may be the inner surface of the belt. The teeth on the belt may engage with corresponding teeth on the drive pulley 25. The belt may be a continuous belt (either formed in this way or made of a single length of material joined together at its two ends).

[0108] The belt is flexible. As mentioned above, belt 24 has inherent stiffness. In other words, the belt elastically resists being bent to change its natural curvature. Therefore, belt 24 is inherently biased to adopt a larger radius (smaller curvature) than drive pulley 25. When untensioned, the belt has a bias forming a curve with a radius larger than the radius of drive pulley 25 (smaller curvature) to release from engagement with drive pulley upon detensioning. In its untensioned state, the belt tends to be circular (or generally tends to be a shape with a bending radius larger than the radius of drive pulley 25). As a result, when the tension force from the belt is released, the belt tends to spring away from drive pulley 25. When the tensioner is released and the belt adopts its untensioned state, as Figure 7a As shown, the band is inherently biased to employ a larger radius than when under tension.

[0109] In the untensioned state, the belt 24 can maintain partial engagement between its teeth and pulley 75, and can have excess length to lift off the drive pulley 25, so that the belt teeth do not engage with the drive pulley. When the belt is flexed past the idler pulley 76, the belt limiter 76a is secured to the belt tensioner arm 73. When the belt tensioner arm 73 rotates to the untensioned position, the belt limiter 76a rotates accordingly and rests against the belt 24, as... Figure 7a As shown, the belt limiter deflects the belt away from the adjacent drive pulley 25, thus preventing it from following a path that would cause it to contact the drive pulley 25. Therefore, in the untensioned state, the rotation of the drive pulley 25 does not cause the belt 24 to move.

[0110] The housing 20 defines an open channel on the outer side immediately adjacent to the drive wheel 25. When tension is released, the belt can expand into this channel.

[0111] like Figure 7a As shown, in the untensioned state, belt 24 follows a path defined by the guide. Two portions of the guide are shown at 78a and 78b. When tension is released from the belt (i.e., when the belt is in the untensioned state), the belt can be biased to bear against the guide outwards. When the belt is in the untensioned state, it may not be fully relaxed because it may be constrained by the guide and unable to utilize its natural curvature.

[0112] The guide is housed within the housing. The guide is configured to restrain the belt to the outside of the drive wheel 25 along the path of the belt 24 disengaging from the drive wheel 25.

[0113] The guide is spaced apart from the drive wheel 25. One section of the guide (such as the section indicated at 78b) may be positioned with a constant radial offset outside the drive wheel. Other sections of the guide may be oriented differently. Figure 7a and Figure 7b In the figure, the section of the guide indicated at 78a extends as the radial offset to the outside of the drive wheel increases, as shown toward the left side of the figure.

[0114] The guide or a portion thereof may be a component independent of the housing. The guide or a portion thereof may be integrally formed with the housing. The guide may be fixed relative to the housing. The guide may extend from the housing 20. The guide may be a continuous component. In other embodiments, the guide may be discontinuous. For example, the guide may include multiple pins or multiple segments (e.g., straight segments or curved segments) for restraining the unstressed band at its desired position within the housing.

[0115] When the belt is tensioned, the guide can be spaced apart from the belt along its entire length. When the belt is de-tensioned, the belt comes into contact with the guide.

[0116] The distance of the belt in its untensioned state relative to the path it follows in its tensioned state can be limited by a guide member against which the belt remains stationary when in its untensioned state. When in its untensioned state, the belt can conform to the shape of the guide member. The guide member can be shaped such that it provides a path for the belt to avoid the drive pulley 25 when the belt is in its untensioned state. The guide member can have a concave shape.

[0117] In some implementations, the belt, in its untensioned state, can be constrained by guides around its entire circumference. Typically, the belt can be constrained in a path where it does not remain engaged with the drive pulley, such that rotation of the drive pulley does not cause movement of the belt.

[0118] Therefore, the guide can hold at least a portion of the belt outside the drive pulley. In some embodiments, the guide may be present not only around the area where the belt 24 engages with the drive pulley 25 when tensioned, but also in other areas between the drive pulley and the wheel 75. Typically, the guide holds the belt along a path such that rotation of the drive pulley 25 does not cause movement of the belt.

[0119] Therefore, when activated by the user, the tensioner 30 relaxes the tension on the belt, causing the belt to return to its natural state toward expansion to rest against the surface of the guide, so that the belt 24 does not engage with the drive wheel 25, while its teeth remain partially engaged with the motor-driven wheel 75.

[0120] The tensioner may include: a manually operable component and a fastening mechanism, the manually operable component being movable from a first position to a second position, in the first position causing the tensioner to apply tension to the belt, and in the second position causing the tensioner to release tension from the belt; and a fastening mechanism for securing the handle in the first and second positions. The manually operable component can be operated by a user without tools (i.e., it can be hand-operated).

[0121] One way to achieve this is to make the belt tensioner an arm that pivots relative to the housing. The arm can be actuated by a lever or other device. Typically, a belt tensioner includes an element that can move relative to the housing to change the path of the belt. This element can move relative to the housing to increase the length of the path traversed by the slack, non-driven portion of the drive belt, thereby applying tension to the drive belt.

[0122] exist Figure 7a and Figure 7b In the example shown, the tensioner includes an arm 73 supporting an idler pulley 76. The idler pulley is rotatable relative to the arm about a fixed axis on the arm. The arm 73, and therefore the idler pulley 76, is movable relative to the housing 20 to increase the length of the path traversed by the slack, non-driven portion of the drive belt, in order to apply tension to the drive belt. The arm 73 (and the idler pulley 76 attached to the arm) rotates about an axis parallel to the axes of wheels 25 and 75.

[0123] Lever 72 can be used to actuate arm 73 to move idler pulley 76. To change the belt from its taut state to its untaut state, lever 72 rotates around... Figure 7a The axis indicated at 40 rotates in the direction of arrow 41. To change the belt from its untensioned state to its tensioned state, lever 72 rotates about axis 40 in the opposite direction of rotation, as indicated by... Figure 7b As indicated by arrow 42 in the image.

[0124] When lever 72 is operated by the user to change the belt to its untensioned state, arm 73 rotates about pivot point 77 (which may be a pin that rotatably fixes arm 73 to housing 20), causing wheel 76 to... Figure 7a Move in the direction indicated by arrow 43 in the diagram.

[0125] When lever 72 is operated by the user to switch the belt to its tensioned state, the arm rotates about pivot point 77, causing wheel 76 to... Figure 7b Move in the direction indicated by arrow 44.

[0126] When the tensioner is actuated to rest against the belt, such as Figure 7b As shown, the tensioner tensions the belt 24 around the drive pulley 25. A spring 79 can be used to help impart a predictable tension force to the belt. In the tensioned configuration, the gearbox output (in this example, pulley 75) and drive pulley 25 are constrained to rotate together at a speed ratio determined by their respective radii. Moving to its tensioned state moves the belt away from the guide, and when the lower pulley 76 moves, it increases the length of the slack section path of the belt.

[0127] The tensioner may include a fastening mechanism for securing the manually operable component 72 in each of a first and a second position. Figure 7b In the example shown, the tension of the belt applies a force to the idler pulley 76, which is transmitted through the arm 73 and the spring 79, thereby positioning the lever 72 in a first position against a stop (not shown) when the cam has moved past the center. Figure 7a In the example shown, the elasticity of the belt applies a force to the idler wheel 76, which is transmitted through the arm 73 and the spring 79, thereby bringing the lever 72 to a second position where the cam is biased toward the center position. The fastening mechanism can take other forms, such as a latch or lock for fastening the lever in the desired position.

[0128] exist Figure 7a and Figure 7b In the example illustrated, the motor's position is fixed relative to the housing. Specifically, the rotation axes of the motor housing and the motor's output shaft are fixed relative to the drive pulley 25. In other embodiments, the motor can be displaced relative to the drive pulley. Specifically, the rotation axes of the motor housing and the motor's output shaft can be displaced relative to the drive pulley in the plane of the belt to selectively apply tension to the belt. In such an embodiment, the additional pulley 76 may not be necessary, and the pulley 75 can be used to selectively apply tension to the belt and can move with the motor.

[0129] When the belt is in the untensioned configuration, the drive wheel 25 can rotate independently of the motor and / or gearbox output. This is convenient because it allows the rider to turn the crank without any connection to the drive unit and allows for a choice between assisted pedaling on the one hand, and unassisted pedaling on the other hand, when the battery is absent or discharged, or when the rider does not want assistance, without resistance from the drivetrain or motor. This is also convenient because, for a drive unit designed for easy attachment and removal from the HPV, when the drive unit is being installed on a human-powered vehicle, it allows the operator to rotate the drive wheel to a position aligned with the crank arm so that the fasteners, mounting holes, etc., on the drive wheel and crank arm are aligned. This makes attaching the drive unit to the human-powered vehicle much easier.

[0130] The drive unit can be arranged to automatically shut off the motor in response to the tensioner being operated to release tension from the belt. For example, a sensor may be present that detects that the tensioner has been operated to release tension from the belt, thus placing the belt in a de-tensioned state. For example, when lever 72 is moved... Figure 7a When the position shown is reached, the sensor can detect that the handle has been moved to this position. In response to this detection, the motor can be automatically turned off.

[0131] Therefore, when the auxiliary function from the motor is not needed (or is unavailable due to low battery power or absence of the battery), the transmission used by the rider to propel the human-powered vehicle can be isolated from the transmission used to transmit auxiliary torque to the human-powered vehicle (e.g., via the crank assembly of the human-powered vehicle). When the auxiliary function is available and / or needed, it can be easily re-engaged.

[0132] cadence decrease Some mid-drive assist bicycles have a clutch built into the mid-drive unit that allows the output of the road wheel (e.g., chain wheel) to rotate forward faster than the bottom bracket axle, enabling the rider to slow down or even stop pedaling completely while the output (e.g., chain wheel) remains on the drive wheel. Such clutches are bulky and expensive. The assist unit (drive unit) disclosed herein avoids the need for such a mechanism, making it lighter and less expensive to manufacture.

[0133] The drive mechanism of this disclosure can be applied to HPVs that do not include clutches, flywheels, or other mechanisms that allow the bottom bracket shaft of the HPV to rotate at a variable rate relative to the output (e.g., chain wheel) of the road wheels driving the HPV. In an HPV to which the drive mechanism of this disclosure can be attached, the cranks, bottom bracket shaft, and drive-side output (e.g., chain wheel) rotate relative to each other at a fixed rate. In other words, the bottom bracket shaft, cranks, and drive-side output rotate as a single unit. Both the cranks and drive-side outputs rotate about the same axis as the bottom bracket shaft. Pedals can be mounted to each crank.

[0134] The drive unit includes a motor and a reduction gear, the motor having a stator and stator windings and a rotor, the reduction gear delivering propulsion output torque from the rotor to the central shaft. The drive unit includes a controller for determining the direction and level of the current delivered to the stator windings, which in turn determines the direction and level of the magnetic torque applied from the stator to the rotor.

[0135] During periods when assistance is needed, because there are non-clutch drive paths between each crank, bottom bracket shaft, and drive-side output, and because the forward torque from the motor is delivered directly to the bottom bracket shaft, it is important that the controller be triggered to immediately withdraw the forward assist torque when the rider wishes to slow down or stop pedaling. It would be unacceptable and / or dangerous for the assist motor to continue driving the crank forward against the rider's will. While the controller can respond to changes in the state of a twist grip or switch operable by the rider, it is preferable that the controller continuously monitors the force generated by the rider while the rider is delivering propulsion through the crank. When assist is being delivered, it is desirable for the controller to apply a certain level of forward torque to the rotor, which is a function of the propulsion force being delivered by the rider. This is possible as long as the controller can monitor the force generated by the rider. When the controller can monitor the force generated by the rider, it can withdraw the assist torque delivered to the rotor once the controller determines that the pattern of the force generated by the rider no longer corresponds to the propulsion force being delivered by the rider. Importantly, the controller can continuously monitor said force regardless of the crank angle.

[0136] Therefore, it is permissible to install one or more sensors to detect displacement of the bearing relative to the HPV frame, in which the bottom bracket shaft rotates in the manner described herein with respect to the fourth salient feature and under the heading “Floating Sleeve.” The controller can monitor changes in the state of these one or more sensors and thereby calculate changes in force caused by the rider.

[0137] During periods when no assistance is required, it is important that the rider can change the crank speed without causing the force, induced by the rotor's inertia and felt by the rider through the pedals, to exceed an acceptable level. On an HPV with a conventional flywheel at the road wheel and without the drive mechanism described herein, the rider will feel very little resistance when moving the pedal forward or backward at a speed too low to engage the flywheel. On an equivalent HPV equipped with the drive mechanism described herein, without the one-way clutch disclosed herein, the rider will encounter resistance from rotor inertia whenever the pedal speed is changed under the same conditions. The controller can apply torque to the rotor, the level and direction of which are calculated by the controller to minimize any undesirable force felt by the rider at the pedals. The controller can make this calculation using observations of the rotor speed and its rate of change, and also using observations of one or more sensors of changes in displacement of the bottom bracket shaft in response to forces induced by the rider. Without the one-way clutch disclosed herein, there will be situations where undesirable forces exceed acceptable levels.

[0138] One such situation occurs when a rider withdraws propulsion to shift to a higher gear. When the new gear engages, the bottom bracket shaft will experience a sudden deceleration or cadence drop unless the rider has already sufficiently reduced their cadence. Because the motor rotor has inertia and is directly connected to the bottom bracket shaft, torque will be needed to impart an equivalent sudden deceleration to the rotor to prevent the motor's inertia from forcing the crank forward. This torque will be transmitted by the drivetrain, which connects the rotor directly to the HPV's own gears via the bottom bracket shaft, and may cause an undesirable jolt and / or lead to harmful stress on the drivetrain.

[0139] The second such scenario might occur, for example, immediately after withdrawing the assist torque, when the rider wants to stop pedaling quickly within a short interval, perhaps to avoid a collision with an obstacle on the road. If the rotor's inertia prevents the rider from slowing the crank as desired, this can be dangerous: if the controller reduces cadence too quickly, it could cause the rider to lose balance, and if too slowly, it could result in a shock at the pedals. Therefore, the controller must apply a certain level of counter-torque to the rotor to reduce speed at a rate sufficiently close to the rate at which the rider wants to slow down the cadence, after adjustments to the gearing. It's unlikely that the controller will be able to react quickly enough in all situations to deliver the correct level of deceleration.

[0140] This control problem is known as the "cadence drop" problem.

[0141] The inventors have recognized that one way to address the cadence drop problem is to include a one-way clutch 80 in the drive path of the drive unit 200 between the motor and the bottom bracket assembly (e.g., bottom bracket shaft, crankset, and drive-side output). The clutch 80 allows the rotor to deliver torque to the bottom bracket shaft when the rotor is rotating at an engagement speed. The engagement speed is a defined multiple of the speed at which the bottom bracket shaft is rotating. The engagement speed can be written as... ,in It is the engagement speed. It is the rotational speed of the central axis assembly, and This is a predefined constant (e.g., 40). The value of "n" is determined by the transmission ratio between the rotor and the central shaft. Clutch 80 disengages when the rotor is rotating forward at a speed below the engagement speed or backward at a speed above the engagement speed. The controller monitors the rotational speed of the central shaft. The controller also monitors the rotational speed of the rotor.

[0142] Figure 8 An example cross-sectional view of a portion of the drive unit is shown, which illustrates a motor 22, a gearbox 23, a wheel 75 driven by the motor, and a drive belt 24. Figure 8 A clutch 80 is shown located between the rotor and the rotor output shaft 84. Alternatively, the clutch may be located in another location within the gearbox 23. Alternatively, the clutch may be integrated into the wheel 75 or into the drive wheel 25. In this example, the clutch 80 is a needle roller clutch. The motor 22 includes a rotor 81, a stator 82, and motor windings 83. The rotor 81 is rotatable in one direction about the rotor output shaft 84. The rotor output shaft 84 carries a sun gear, which is the input to the planetary gearbox. When the clutch 80 is engaged, the forward magnetic torque applied to the rotor 81 delivers a forward torque to the rotor output shaft 84. As the rotor drives the HPV forward, the rotor output shaft 84 rotates forward, the sun gear meshes with the large planet of the planet pair 85, and causes the planet pair 85 to rotate about a second shaft 86. The small planets of the planet pair 85 interact with a ring gear 87, causing the planet gears to move about the ring gear 87 to rotate the planet carrier 88. The rotation of the ring gear 87 relative to the housing is prevented by a flexible mount 89, which is fixed to the gearbox housing 20. The flexible mount 89 allows for a degree of radial float in the ring gear. Rotation of the planet carrier 88 imparts rotation to the output shaft 90, which is coupled to a wheel 75 that drives the belt 24. The belt 24 can transmit torque to a drive wheel 25, which is connected to the central shaft of the HPV.

[0143] At fixed intervals, the controller can recalculate the torque to be applied to the rotor. At each such interval, the controller obtains values ​​for motor speed and direction from the commutator circuitry and sensors. Individually, sensor 91 can be mounted on printed circuit board 93, which may also carry circuitry including the controller. At each interval, the controller obtains values ​​representing crank speed and direction from sensor 91, which responds to changes in magnetic flux generated by the rotation of magnet 92 attached to output shaft 90. Due to the mechanical connection provided by belt 24, the speed at which shaft 90 rotates is a fixed multiple of the speed at which the bottom bracket shaft rotates, and the controller can calculate the rider's cadence by dividing the speed of shaft 90 by this fixed multiple. The controller can then calculate an engagement speed applicable to the cadence observed during that interval, even if the rotor itself may not be rotating at that engagement speed.

[0144] First, we will describe two benefits provided by the one-way clutch 80.

[0145] If clutch 80 is absent and rotor 81 is directly coupled to rotor output shaft 84, and the rider reduces forward cadence, the forward speed of the rotor is correspondingly reduced. The torque required to decelerate the rotor can be mechanically applied by the rider through the pedals, which may cause the rider to feel an undesirable force through the pedals. The torque required to decelerate the rotor can also be magnetically applied by the controller. Since it is desirable to minimize the rider's contribution to rotor deceleration, the controller can estimate the ideal level of reverse torque to be applied to the rotor at each interval. This ideal level of reverse torque is such that when applied to the rotor during subsequent intervals, it will eliminate the force from rotor inertia felt by the rider. The estimation of the ideal level of reverse torque can be made, for example, by referencing the most recent rate of change in cadence observed by the controller and the most recent readings obtained from one or more sensors of the displacement of the bottom bracket shaft in response to the force induced by the rider. The controller can then apply the estimated ideal level of reverse torque to the rotor. In this way, during periods of gentle cadence reduction, the controller may maintain the undesirable force felt by the rider through the pedals at an acceptable level. However, during periods of rapid cadence drop, the controller may struggle to react quickly enough to make a reliable estimate of the ideal counter-torque level at each interval, and the torque level applied to the rotor by the controller may deviate from the actual ideal level: the controller may determine and apply too much or too little counter-torque, or fluctuate between the two, resulting in an undesirable force at the pedal that is unacceptable to the rider.

[0146] However, when the drive unit includes a clutch 80, the controller can apply a certain amount of counter-torque to the rotor that is higher than the estimated ideal level, exceeding any possible deviation between the estimated and actual ideal levels. Because the clutch can disengage, the rider does not have to bear the force from the rotor's inertia transmitted through the pedals, and due to the "overbraking" applied to the rotor by the controller, the rider may feel little or no discomfort from the pedals. The clutch allows the controller to always tend to apply a higher counter-torque to the rotor than the estimated ideal level in such situations, and this makes the controller's task practical, especially during periods of rapid cadence drop. This is the first benefit.

[0147] A second benefit of including a clutch 80 in the drivetrain is that, when the pedals are rotating forward and no assistance is needed, the controller can maintain the rotor at an idle speed below the engagement speed. This idle speed could be, for example, zero, but this would mean that when assistance is needed again, the rotor must accelerate back to the engagement speed. Instead, an idle speed can be selected that is a defined idle speed difference below the engagement speed, such that when the rider shifts to a new, higher gear, for a typical gear change, at the moment of engagement of the new gear, the rotor is unlikely to rotate at a speed higher than the reduced engagement speed at that moment, thus avoiding the undesirable jolts mentioned above and preventing harmful stress on the drivetrain.

[0148] Now refer to Figure 9 An example of a process that can be followed to determine the level and direction of torque to be applied to the rotor when the drive unit includes clutch 80 is described below. The invention is particularly relevant in cases where the pedal is moving forward and no assistance is needed (e.g., the answer to step S900 is "no"). Alternative processes or methods not described herein can provide equivalent control both when the pedal is moving forward and no assistance is needed and when the drive unit includes clutch 80.

[0149] When the controller senses that the motor speed is the same as the calculated engagement speed (e.g., the response to step S901 is "yes"), as is typically the case in the first interval immediately following the withdrawal of the auxiliary torque, the controller recognizes a state referred to herein as "lockout." During lockout, the rider may push the pedals backward against rotor inertia with an undesirable force, and the controller's goal is to quickly escape the lockout. A simple procedure for the controller is to apply the maximum available escape lockout torque to the rotor during any interval when the controller recognizes a lockout. This will reduce the rotor speed quickly enough so that the rider does not feel rotor inertia during the rapid drop in cadence, but this will exceed the threshold at which the rider will feel the jolts caused by the reaction torque transmitted from the stator to the HPV frame. Since such bumps are unacceptable when the rider withdraws force and reduces cadence in a normal, relaxed manner, the controller, instead of recognizing a lockout (e.g., when the answer to step S901 is "yes"), calculates (e.g., at step S913) the higher of the default escape lockout torque and the high escape lockout torque during any interval.

[0150] The default escape lockout torque applied to the rotor can be a low multiple of, for example, between 1 and 3, a torque that, in the absence of any other torque applied to the rotor, will sufficiently decelerate the rotor to disengage the clutch 80 when the rider reduces their cadence at a rate typical for the cadence in question and at a normal, gentle rate of pedaling deceleration without any torque on the bottom bracket shaft caused by rotor inertia. The default escape lockout torque will be below the threshold at which the rider will feel a bump caused by the reaction torque transmitted from the stator to the HPV frame.

[0151] The high escape lockstep torque will be the smaller of the maximum escape lockstep torque and the larger escape lockstep torque.

[0152] The maximum escape lockout torque will be the maximum available reverse torque of the rotor, as limited by the limit on the reverse stator current set for the controller. This will be rarely invoked, only in special circumstances: the torque applied to the rotor is likely to exceed the threshold at which the rider will feel the jolts caused by the reaction torque transmitted from the stator to the HPV frame.

[0153] The larger escape lockout torque will be calculated by the controller based on several variables. For example, one variable could be the level of the counter-paddle force, which can be calculated by the controller based on readings from one or more sensors of changes in displacement of the bottom bracket shaft in response to forces exerted by the rider during the previous interval. In other words, the more the rider pushes backward, the higher the rotor braking ramp. Another variable could be, for example, a factor that increases with the count of intervals elapsed since the controller first detected a lockout during the current slowdown of the crank. In other words, the longer the rider pushes backward, the more the controller ramps up the rotor braking. Yet another variable could be the difference between the actual measured speed of the motor and the calculated expected speed of the motor, which the controller anticipates the motor will rotate at if the clutch is disengaged. The torque applied to the rotor may exceed or not exceed a threshold at which the rider will feel a bump caused by the reaction torque transmitted from the stator to the frame of the HPV.

[0154] When the crank and rotor disengage from the lockout (e.g., when the answer to step S901 is "no"), the controller will sense that the rotor is rotating at a speed lower than the engagement speed, and / or the rider is no longer pushing the pedal backward, and the controller can withdraw the escape lockout torque.

[0155] When disengaging from the lock step, the controller continuously monitors whether conditions are suitable for resuming the application of auxiliary torque to the rotor (e.g., whether the answer to step S900 becomes "yes"). If this is not the case, the controller monitors the cadence (e.g., at step S912) and calculates the idle speed as the calculated engagement speed minus the idle speed difference. At each interval, the controller calculates the torque to be applied to the rotor that is most likely to maintain the rotor speed equal to the calculated idle speed.

[0156] When the rotor is spinning below engagement speed and the forward cadence is increasing, the controller can apply forward torque to maintain idle speed. When the rotor is spinning below engagement speed and the forward cadence is decreasing, the controller can apply reverse torque to maintain idle speed. When the forward cadence suddenly drops, the controller can apply reverse torque to the rotor that is insufficient to maintain the rotor speed equal to its calculated lower idle speed at this time. However, because the idle speed difference will be greater than any difference between the actual rotor speed and the calculated idle speed that might occur if the controller applied too low a reverse torque to the rotor, the rotor speed can be maintained below engagement speed, and the rider will not experience unwanted forces at the pedals due to rotor inertia.

[0157] The decision at step S900 whether to provide assistance can be based on input data from the rider and / or data collected by the drive unit itself.

[0158] For example, HPV may include a switch that can be operated by the rider. When the rider wishes to turn off the assistance from the motor, they can operate the switch to the "off" position (e.g.). When the controller receives a signal from the rider (e.g., via the control switch) that they do not want the assistance, it will determine whether the answer to step S900 is "no".

[0159] For example, the controller can determine whether assistance will be deactivated based on the force detected on the pedals. For instance, the controller can be configured to receive indications of forces applied by the rider to the bottom bracket axle, such as from a bottom bracket assembly as described herein. The controller can decide to provide assistance in response to the indicated torque exceeding a predefined threshold. The controller can further decide not to provide assistance in response to the sensed torque on the bottom bracket axle falling below a predefined threshold.

[0160] For example, the controller can decide not to provide assistance based on the measured speed of the bottom bracket assembly. If the measured speed of the bottom bracket assembly is zero, it can be concluded that the rider has stopped pedaling and therefore no assistance is needed.

[0161] When assistance is required (e.g., the answer to step S900 is "yes"), the controller checks at step S902 whether the motor is rotating at the engagement speed. If yes, the clutch is engaged and the controller can apply torque to the motor to provide assistance to the central shaft assembly. If the motor is not rotating at the engagement speed, the clutch is not yet engaged, so the controller applies torque to the motor to increase its forward speed until it reaches the engagement speed, after which assistance can be provided according to steps S904 and S905.

[0162] Floating sleeve The following describes a bottom bracket assembly that can detect the rider's pedaling force on a bicycle (or other HPV) by measuring the radial displacement of the bottom bracket axle relative to the bicycle frame caused by elastic strain. This radial displacement occurs when an unbalanced lateral force is applied to the bottom bracket axle. Specifically, the radial displacement occurs when the rider's force on one side of the bicycle's pedal differs from the rider's force on the other side's pedal. The radial displacement can also occur when the line of force generated by the forward delivery of rider power (e.g., via a continuous chain or belt, or via a gear-wheel) shifts to a particular side of the bicycle. In normal operation of a conventional bicycle, this force may shift to the side of the bicycle where the chain or belt is located, referred to as the drive side. In other words, the radial displacement can occur when tension is present in the drive chain. The radial displacement can also be caused by the force carried by the connection between the output of the auxiliary motor and the drive wheel on the bottom bracket assembly (e.g., a continuous chain or belt, or a gear-wheel). Lateral force refers to a force acting in a direction transverse to the longitudinal axis of the bottom bracket axle.

[0163] The sensor is used to measure the radial displacement. The control processor for any drive unit described above can respond to the value of the rider force that the control processor can derive from the readings from the sensor.

[0164] There is more than one arrangement for the bottom bracket assembly, which includes a sleeve capable of providing measurable radial displacement in response to rider forces. Reference will now be made to... Figures 10 to 15 Three examples are provided to describe such a central axis component.

[0165] The bottom bracket assembly includes a bottom bracket body and at least two bearings. The bottom bracket body is radially supported by the bearings at two separate locations along its length, within which the bottom bracket body can rotate. The assembly also includes a hollow sleeve that carries the bearings. The assembly further includes multiple axially separated mounting structures. These mounting structures radially support the sleeve. At least one mounting structure provides axial support to the sleeve. At least one mounting structure prevents the sleeve from rotating. The mounting structures connect the sleeve to the bottom bracket housing on the bicycle frame. These include a first mounting structure on or near the drive side of the bicycle and a second mounting structure closer to the opposite side (non-drive side) of the bicycle than the first mounting structure. The first mounting structure provides a fulcrum about which the sleeve can rotate in yaw and roll.

[0166] The second mounting structure is radially compliant. An unbalanced lateral force is generated when the torque of the force induced by the rider about the fulcrum provided by the first mounting structure in one direction is not equal to the torque of these forces in the other direction (the difference being the torque induced by the rider). The radial force in the compliant second mounting structure supporting the sleeve towards its non-drive side generates a torque about the fulcrum located at the first mounting structure. This torque is equal to and opposite to the torque induced by the rider. Due to the compliance of the second mounting structure, the sleeve produces a radial displacement in a given direction. The amount of radial displacement depends firstly on the amount of the unbalanced lateral force in that direction, and secondly on the axial distance from the fulcrum. Since the sleeve does not rotate, the sleeve displacement can be easily measured. One or more sensors can respond to changes in the sleeve's radial displacement caused by the unbalanced lateral force on the bottom bracket shaft. Each sensor can be used to deliver an electrical signal indicating the level of the external unbalanced force on the bottom bracket shaft in a given direction. The component can measure this external force continuously or nearly continuously. A controller can monitor each electrical signal. The controller can use this information to determine the level and direction of the torque delivered by the motor to assist the HPV rider.

[0167] As mentioned above, this article references Figures 10 to 15The described spindle assembly includes a sleeve that houses at least two bearings and the spindle body. If the sleeve is sufficiently resistant to bending, two advantages can be achieved by carrying the bearings within it. First, the position of the line of radial support provided by the first mounting structure can be axially offset relative to the line of radial force transmitted through the drive-side bearings. This allows the axial position of the first mounting structure, and therefore the axial position of the fulcrum, to differ from the axial position of the drive-side bearings. Second, the radial displacement of the spindle body can be measured at any point along the length of the sleeve and away from the fulcrum.

[0168] Containing the bearing within a sleeve offers several advantages, provided the sleeve has sufficient resilience in tension or compression. The support provided to the sleeve by the mounting structure can include an axial force component in addition to the radial force component. This axial force component is typically balanced by an equal and opposite axial force component provided to the sleeve by another mounting structure. Such axial forces between the mounting structures generate equal axial forces within the sleeve, which will be either tensile or compressive, depending on the direction of the axial forces at the mounting structure. Because these additional loads are borne by the sleeve between the mounting structures, rather than through the bearing and the bottom bracket shaft, the bearing itself (whose primary function during normal pedaling is to provide radial support to the bottom bracket shaft) does not bear the additional axial loads introduced at the mounting structure. Therefore, if the mounting structure is intentionally arranged to bear both radial and axial loads, there is no increase in load on the bearing, nor is the bearing life shortened.

[0169] Another advantage of this arrangement is that if compliance at the second mounting structure is to be provided by the elastomer, and if the surface of the adjacent elastomer is to be arranged at an angle relative to the central axis to generate a shear strain component in the elastomer during radial displacement of the sleeve, and thus to produce a more linear force-displacement relationship than when the surface of the adjacent elastomer is parallel to the central axis and the elastomer is only subjected to compressive loads, then at the compliant mounting structure, a single elastomer element will be sufficient, rather than a pair of opposing elastomer elements.

[0170] Another advantage is that the axial offset of the fulcrum provided by the first mounting structure can be further controlled, thereby providing geometrically equivalent support for the sleeve at the first mounting structure to the support that would be provided by a spherical bearing whose center is located on the axis of the central axle shaft with a selective offset from the centerline of the bicycle or HPV, as illustrated in the first and third examples of the three examples described below.

[0171] Now refer to Figures 10 to 15 Describe the axis components in the three examples.

[0172] The following features are common in each of the three examples. The bicycle's bottom bracket assembly, to which the frame is mounted, includes a hollow bottom bracket housing 9 with drilled holes at each end for threading. The bottom bracket assembly described in the following three examples includes a hollow sleeve housing. The assembly also includes a bottom bracket axle 12. The bottom bracket axle is constrained to rotate about its axis within the bottom bracket housing. The bottom bracket axle can be connected at one end to a crank 13 and at the other end to a crank 15. Each crank carries a pedal (not shown) to which the rider can apply force. When the bottom bracket assembly is mounted to the bicycle frame and the axle is attached to the crank, and the crank is attached to the pedal, the torque about the axis of the bottom bracket axle generated by the force applied to the pedal is resisted by an equal and opposite torque generated in the wheel 14 by the force required to propel the bicycle. The wheel 14 is located on the bicycle's side 101, referred to as the drive side. The wheel 14 can be attached to the crank 13 and rotates with the crank 13. The other side 102 of the bicycle is referred to as the non-drive side.

[0173] Example 1 Figure 10 A first example of a bottom bracket assembly 150 is shown, which includes a sleeve 120 positioned within a bottom bracket housing 9 of a bicycle. The sleeve 120 has threads at each end on its outer side.

[0174] This first example will now be described in the context of assembling and installing it into the central housing of the HPV.

[0175] First, the thrust bearing component of the first example assembly will be described. In this example, the assembly includes a pair of inner bearing raceways 130, a pair of retaining rings 131, and an outer bearing raceway 129. The pair of inner bearing raceways 130 are mounted on the central shaft body 12. The inner bearing raceways are constrained by the pair of retaining rings 131 to prevent axial movement apart on the central shaft body. A sleeve 120 carries the outer bearing raceway 129 within its bore. Bearing balls 132 (also part of the assembly) are held between the inner and outer raceways. The manner in which the assembly provides the constraint of preventing axial movement apart on the outer raceway and provides axial positioning for the central shaft body will be explained further below.

[0176] The central shaft 12 is radially supported toward the drive side 101 by a bearing 105, and radially supported toward the non-drive side 102 by a second bearing 106. These bearings can be ordinary bearings or may include rolling elements; in this example, needle roller bearings are used.

[0177] Each bearing cup is pressed into a bore in the sleeve 120. The assembly also includes a thrust bearing isolator 128 abutting against the inner side of each bearing cup. Opposite ends of each isolator 128 abut against the outward-facing shoulder of the outer raceway 129 of the assembly.

[0178] A first mounting structure 1103 on the drive side connects the drive side of the sleeve to the central shaft housing. In this example, the first mounting structure consists of a drive-side end cup 103 and an elastomer diaphragm 122.

[0179] The elastomeric diaphragm is thin. The elastomeric diaphragm can be of any suitable thickness to achieve the technical effects described herein. In other words, the thickness of the elastomeric diaphragm is sufficient to allow the diaphragm to deform under shear to accommodate rotation during yaw or roll caused by radial displacement of the sleeve at the second mounting structure. Such displacement can be up to 0.1 mm (depending on the pedaling force). In one example, the thickness of the elastomeric diaphragm can range from 0.1 mm to 1 mm. For example, the elastomeric diaphragm can be 0.2 mm thick. The elastomeric diaphragm has a tapered shape.

[0180] The elastomeric component abuts a mating tapered surface formed on the inner side of the drive-side end cup 103 and also abuts a mating tapered surface on the outer side of the threaded clamping nut 124. Therefore, the surface of the elastomeric diaphragm that contacts the rigid element of the first mounting structure is positioned at an angle to the longitudinal axis of the central shaft. The elastomeric diaphragm 122 can be glued to the end cup 103 and the clamping nut 124. Preferably, if glue is used, during gluing, the semi-circular holes formed in each of the end cup and the clamping nut are aligned to provide a circular recess 126 that a pin wrench can engage with during assembly. The clamping nut 124 is tightly secured to the threaded drive-side end of the sleeve 120 such that the inwardly projecting flange 124a of the nut 124 abuts the end of the sleeve. Threaded locking can be used here.

[0181] The sleeve tube 120, clamping nut 124, thrust bearing components 128, 129, 130, 131, 132, shaft 12, needle roller bearings 105, 106, and first mounting structure 1103 (including diaphragm 122 and drive-side end cup 103) constitute sub-assembly A of the central shaft assembly.

[0182] A second mounting structure 1104 on the non-drive side connects the non-drive side of the sleeve to the central housing. In this example, the second mounting structure includes a compliant non-drive side end cup assembly 139.

[0183] The non-driven end cup assembly 139 includes a tapered elastomer ring 138, a non-driven end cup 104, and an expansion ring 137. The expansion ring 137 is rigid. The elastomer ring abuts a mating tapered surface formed inside the non-driven end cup 104 and also abuts a mating tapered surface inside the rigid expansion ring 137. The elastomer ring 138 can be glued to the end cup 104 and also glued to the expansion ring 137. Preferably, if glue is used, during gluing, a circular hole 136 is provided in each expansion ring 137, keeping the elastomer ring 138 and the end cup 104 aligned so that a pin wrench can be engaged to secure the non-driven end cup assembly.

[0184] The assembly also includes an expansion box 140. During assembly, the expansion box 140 is positioned onto the non-drive side of the bottom bracket housing and is securely clamped against the bottom bracket housing by screwing the end cup assembly 139 into the threads in the non-drive side of the bottom bracket housing.

[0185] Sub-assembly A can be installed as a complete item through the drive side end of the center column housing 9, wherein the threaded non-drive side end of the sleeve 120 passes through the end cup assembly 139. The drive side end cup 103 is screwed into the threads inside the drive side end of the center column housing. Initially, sub-assembly A may need to be screwed in deeper than it will occupy after final adjustment.

[0186] The non-drive side clamping nut 134 can be screwed into the threaded non-drive side end of the sleeve 120.

[0187] The expansion box 140 has an expansion box cover 141, which is positioned inside the outer flange 134b on the clamping nut 134. The clamping nut 134 is tightened until its inwardly projecting flange 134a is in close contact with the non-drive end of the sleeve 120.

[0188] The inwardly projecting flanges 124a and 134a of each clamping nut restrict the outward axial movement of each bearing 105, 106 from the bore in the sleeve 120. This, in turn, captures each thrust bearing retainer 128, and consequently each outer bearing raceway 129. When the spindle body 12 is subjected to an external axial load from the drive side, the load is transmitted via the drive-side retainer 131, the drive-side inner raceway 130, the bearing balls 132, the non-drive-side outer raceway 129, the non-drive-side retainer 128 adjacent to the outer raceway, the cup of the non-drive-side needle roller bearing 106, the flange 134a of the clamping nut 134, and finally via subassembly A to the drive-side end of the spindle housing. When the bearings are subjected to an external axial load from the non-drive side, an equivalent load path can be applied. The running clearance of the bearing balls 132 is determined by the length of the sleeve tube 120, the length of the needle roller bearings 105 and 106, the length of the spacer ring 128, the length of the bearing raceways 129 and 130, and the spacing of the retaining rings 131. If the axial clearance of the central shaft body 12 is to be minimized, shims (not shown) may be selectively used.

[0189] As mentioned above, when assembling the center column assembly, sub-component A may need to be screwed in deeper than it will occupy after the final adjustment. The final adjustment will now be described.

[0190] A pin wrench can be used to engage within the ring hole 126. Sub-assembly A can be unscrewed from the threaded drive side end of the spindle housing 9, thereby moving sub-assembly A together with the clamping nut 134 toward the drive side of the spindle housing. As a result of this movement, the tapered inner surface of the clamping nut 134 abuts against the mating tapered outer surface of the expansion ring 137. Lubricant can be present on the abutting tapered surfaces of the clamping nut 134 and the expansion ring 137 to reduce frictional resistance to relative rotation when sub-assembly A is unscrewed from the drive side end of the spindle housing. An axial compressive force is generated within the tapered elastomer ring 138, which is equal to and opposite to the axial compressive force within the tapered elastomer diaphragm 122. Unscrewing sub-assembly A from the drive side end of the spindle housing is stopped when the torque reaches a level sufficient to cause a sufficient axial preload on the elastomer ring 138. The sleeve 120 becomes subjected to tensile stress. With the preload, a second mounting structure is now established for the non-drive side end of the sleeve 120, which includes a compliant end cup assembly 139.

[0191] The component may also include a locking ring 143 to lock the drive-side end cup 103 in a selected position. The outer flange 134b on the clamping nut 134 now abuts against the expansion box cover 141 so as to capture it against the expansion box 140 and the inner and outer seals are in place to prevent water from entering the spreader-box enclosure 142.

[0192] The manner in which the first mounting structure at the drive-side end provides a fulcrum 123 tending toward the position shown is now explained. The compliance of the elastomeric diaphragm 122 under tension and compression is lower than its compliance under shear. Therefore, the diaphragm provides high resistance to the linear movement of the drive-side clamping nut 124 relative to the drive-side end cup 103, and low resistance to rotation of the drive-side clamping nut 124 relative to the drive-side end cup 103 during yaw and roll. The reason why the fulcrum 123 tends toward the position shown is that this position is also the center of a hemisphere, a portion of which is substantially defined by the conical ring of the elastomeric diaphragm 122, and the compressive / tensile strain induced within the elastomeric body is at a minimum when rotating about this fulcrum. When the line of the external force induced by the rider on the mid-axle shaft does not pass through this fulcrum, it generates a torque about this fulcrum, which is balanced by an equal and opposite torque about this fulcrum generated by the radial force at the second non-drive-side mounting structure.

[0193] A combination of axial position and angle of the tapered or partially spherical mating surface of the elastomeric diaphragm 122 can be selected to provide a preferred axial offset of the fulcrum 123. In other words, the axial position of the fulcrum is determined by the axial position of the elastomeric diaphragm and the angle formed by the elastomeric diaphragm and the longitudinal axis of the central shaft.

[0194] When the second non-drive side mounting structure is subjected to a radial load in a given direction, radial displacement in the same direction occurs in the sleeve 120, as well as the clamping nut 134 and the expansion ring 137, due to the compliance of the tapered elastomer ring 138. The amount of this displacement is a function of the radial load. This displacement can be measured by strain gauges or other sensors within the assembly.

[0195] For example, Figure 10 and Figure 11 A sensing arrangement that can form part of this component is shown. The sensing arrangement includes a beam 145 inside the expansion box closure 142 (see [reference]). Figure 10 The beam 145 is supported such that its center rests against an expansion ring 137. The expansion ring 137 induces initial strain in the surface of the beam near its center. When there is any movement of the expansion ring 137 perpendicular to the beam 145, the strain in the beam at its center changes. A sensing arrangement may include a strain gauge 146 attached to the beam 145 to detect changes in strain in the beam. The strain gauge 146 may be connected to a PCB 147, where circuitry is provided to deliver an electrical signal that consistently indicates the strain in the beam 145. This electrical signal may be used by a controller (not shown) to determine the level of unbalanced lateral forces induced by the rider around the pivot point in a direction perpendicular to the beam 145.

[0196] The sensing arrangement can also be equipped with a second beam 148, which is positioned against different portions of the outer edge of the expansion ring 137. The second beam 148 can carry strain gauges 149, which are also connected to the PCB 147 to generate an equivalent electrical signal that can be used by the controller to determine the force exerted by the rider perpendicular to the second beam 148. When the controller has information about forces in more than one direction, it can extract not only the difference in force applied to each pedal, but also the tension in the drive chain if the pivot point shifts from the line of the drive chain, and similarly, the force in any connection between the drive wheel on the bottom bracket assembly and the output of the auxiliary motor.

[0197] Preferably, the sensing arrangement includes a pair of strain gauges positioned at right angles to each other. The controller can be configured to determine the level of unbalanced external force applied to the central axis assembly in any direction based on readings from the pair of strain gauges.

[0198] Example 2 Figure 12 and Figure 13 A second example of a central shaft assembly 250 including a sleeve 120 is shown. The outer side of the sleeve 120 has threads at each end.

[0199] This second example will now be described in the context of assembling and mounting it into the central housing of the HPV.

[0200] First, the thrust bearing component of the second example assembly will be described. In the second example, assembly 250 includes a pair of inner bearing rings 160, a retaining ring 161, and a pair of outer bearing rings 159. The pair of inner bearing rings 160 are mounted on a central shaft body 12. Each bearing ring is constrained in one direction by the retaining ring 161 to prevent axial movement relative to the central shaft body 12. The pair of outer bearing rings 159 are carried within a bore in a sleeve 120. The bearing rings 159 are provided with a standard thrust bearing surface at each side 162. The bearing surfaces can be lubricated. The assembly provides the outer bearing rings with a non-axially movable separation constraint and provides the central shaft body with an axial position within the sleeve in a manner equivalent to that described above for the first example.

[0201] The central shaft 12 is radially supported towards the drive side 101 by a needle roller bearing 105, and radially supported towards the non-drive side 102 by a second needle roller bearing 106. The cup of each needle roller bearing is pressed into a bore in the sleeve 120. An outer bearing ring 159 may abut the inner side of the cup of each needle roller bearing.

[0202] The first mounting structure 2103 on the drive side includes an end cup 153. In this example, the end cup 153 partially has a groove. The end cup 153 carries an internal thread that can engage with the threaded side of the sleeve 120, and an external thread that can engage with the drive-side thread in the drilled hole of the central housing 9. The end cup 153 is fastened to the threaded drive-side end of the sleeve 120 such that an inwardly projecting flange 153a abuts the end of the sleeve. Thread locking can be used here. The sleeve 120, thrust bearing components 159, 160, 161, 162, shaft 12, needle roller bearings 105, 106, and end cup 153 constitute a subassembly 180.

[0203] During assembly, the expansion box 170 is positioned onto the non-drive side of the bottom bracket housing. The expansion box 170 is securely clamped against the bottom bracket housing by screwing the non-drive side cup 154 ​​into the thread of the non-drive side of the bottom bracket housing.

[0204] A compliant expansion beam 167 is housed within an expansion box 170. The expansion beam 167 has a hollow center 167b with a tapered bore 167e. The expansion beam carries a threaded boss 167a.

[0205] The expansion box 170 has an expansion box cover 171 with a tapered drilled hole 171a. The expansion box cover 171 is securely attached to a threaded boss 167a carried on the expansion beam 167 by screws 174 and 175. The tapered drilled hole 167e of the expansion beam is arranged in the opposite direction to the drilled hole 171a.

[0206] The profile of the expansion beam 167 allows for radial compliance of its threaded boss 167a relative to the hollow center 167b when the expansion beam 167 bears a radial load. A circular elastomeric seal is captured between the cap 171 and the center 167b of the expansion beam.

[0207] Sub-assembly 180 can be installed as a complete unit through the drive-side end of the center column housing 9, wherein the threaded non-drive-side end of the sleeve 120 passes through the non-drive-side end cup 154. The drive-side end cup 153 is screwed into the threads inside the drive-side end of the center column housing. Initially, sub-assembly 180 may need to be screwed in deeper than it will occupy after final adjustment.

[0208] The cover 171, along with its attached expansion beam 167 and the seal 178 surrounding its outer edge, can be positioned into the expansion housing 170 during assembly. The protruding end of the screw 174 engages with an elastomeric bushing 181 mounted within the expansion housing, thereby providing the correct angular position of the expansion housing cover and the attached expansion beam relative to the expansion housing 170. The non-drive end cup 154 ​​carries an external taper that can mate with the tapered bore 167e of the expansion beam 167. The clamping nut 164 carries an external taper that can mate with the tapered bore 171a of the expansion housing cover. The clamping nut 164 can be screwed onto the threaded non-drive end of the sleeve 120 and tightened until its inwardly projecting flange 164a tightly abuts the non-drive end of the sleeve 120.

[0209] As mentioned above, when assembling the center column assembly, sub-assembly 180 may need to be screwed in deeper than it will occupy after the final adjustment. The final adjustment will now be described.

[0210] A special wrench can be used to engage the drive-side end of subassembly 180 and to unscrew subassembly 180 from the threaded drive-side end of the central shaft housing 9, thereby moving subassembly 180, together with clamping nut 164, toward the drive side of the central shaft housing, such that the outer taper on clamping nut 164 engages with the mating tapered bore 171a of expansion cover. Cover 171, together with its attached expansion beam 167, is pulled inward until the tapered bore 167e of expansion beam 167 abuts against the outer taper on end cup 154. Lubricant can be present on the adjacent tapered surface of clamping nut 164 and the tapered bore 171a of expansion cover 171 to reduce frictional resistance to relative rotation when unscrewing subassembly 180 from the drive-side end of the central shaft housing. Stop unscrewing subassembly 180 from the drive-side end of the bottom bracket housing when the torque reaches a level sufficient to maintain engagement of the tapered surface at the non-drive end under radial loads induced during riding. Sleeve 120 then experiences light tensile stress. The assembly may include a locking ring 143 to lock the drive-side end cup 153 in a selected position.

[0211] The second mounting structure 2104 on the non-drive side includes an expansion box cover 171, screws 174 and 175, an expansion beam 167, and a non-drive side end cup 154.

[0212] The second mounting structure for the non-drive side end of the sleeve 120 is now in place. When a radial load caused by the rider is transmitted from the non-drive side end of the bottom bracket axle through the bearing 106 and via the sleeve 120 and clamping nut 164 into the tapered bore 171a of the cap, the cap 171 has sufficient strength to transmit the load to the screws 174, 175. This load is then transmitted by the expansion beam 167 via the end cup 154 ​​into the bottom bracket housing 9.

[0213] The seal 178 surrounding the outer edge of the cover is radially captured between the inner surface of the cover and the outer edge of the expansion box 170.

[0214] The first mounting structure at the drive-side end is now described in such a way that it provides a fulcrum 157 tending toward the position shown. If there is no radial support for the sleeve at the non-drive-side end when an unbalanced lateral force is applied to the central shaft, the radial movement of the sleeve relative to the central shaft housing 9 will be produced by a combination of the compliance of the central shaft housing toward the drive-side end, the compliance of the end cup 153, and the compliance of the bending of the sleeve tube 120. The exact axial offset of the virtual fulcrum around which the lateral force rotates will depend on the compliance, but this offset is likely to be located at or near the position shown for fulcrum 157.

[0215] When the second non-drive side mounting structure is subjected to a radial load in a given direction, radial displacement occurs in the same direction for the sleeve 120, the clamping nut 164, the expansion box cover 171, and the threaded boss 167a on the expansion beam due to the compliance of the expansion beam profile. Such displacement can be as high as 0.05 mm (depending on the stepping force). This displacement can be measured by a sensor, such as a strain gauge.

[0216] For example, Figure 13 A sensing arrangement that can be part of this component is shown. The sensing arrangement may include a strain gauge 183 attached to an arm 167c of the expansion beam 167. The strain gauge is connected to a PCB 185, where circuitry is provided to deliver an electrical signal that always indicates the strain in the outside of the arm 167c for analysis by a controller (not shown).

[0217] In a similar manner, the sensing arrangement may be further fitted with a second strain gauge 186 attached to the arm 167d. This second strain gauge 186 can be used to determine the strain caused by the radial displacement of the sleeve 120 in different directions, and also for analysis by the controller. As in the first example, the sensing arrangement is preferably arranged to measure forces in different directions, so that the controller can determine the level of unbalanced external forces applied to the central shaft assembly in any direction based on the readings from the pair of strain gauges.

[0218] Example 3 Figure 14 and Figure 15 A third example of a central shaft assembly 350 including a sleeve tube 120 is shown. This third example will now be described in the context of assembling and mounting it into the central shaft housing of an HPV.

[0219] In this example, the second mounting structure 3104 includes a non-driven end cup 205, an elastomeric ring 206, and a washer 207. The elastomeric ring 206 has a tapered shape. The washer 207 has a shape corresponding to the elastomeric ring (e.g., a tapered shape).

[0220] The elastomeric ring 206 abuts against a mating conical surface formed inside the non-drive side end cup 205, and on its other side, the ring 206 abuts against a mating conical surface formed outside the conical washer 207. The elastomeric ring 206 can be glued to the end cup 205 and also glued to the conical washer 207.

[0221] The assembly includes an expansion backplate 223. The expansion backplate is mounted to the non-drive side of the center bracket housing 9. An end cup 205, together with an elastomer ring 206 and a tapered washer 207, is screwed into a threaded hole at the non-drive end of the center bracket housing and tightened to securely clamp the expansion backplate 223 against the side of the center bracket housing.

[0222] The assembly also includes a sleeve assembly 217. The sleeve assembly 217 comprises: a central shaft body 12, a drive-side sleeve housing 201, a non-drive-side sleeve housing 202, bearings 105 and 106, a pair of inner bearing raceways 211, a pair of outer bearing raceways 210, a pair of retaining rings 212, a set of bearing balls 213, an elastomer diaphragm 204, and a drive-side end cup 203. The elastomer diaphragm 204 and the drive-side end cup 203 constitute a first mounting structure 3103. The elastomer diaphragm 204 has the same properties as the elastomer diaphragm in the first example. For example, the elastomer diaphragm has a tapered shape.

[0223] A tapered elastomer diaphragm 204 abuts against a mating tapered surface formed inside the drive-side end cup 203, and its other side abuts against a mating tapered surface formed on the outside of the drive-side sleeve housing 201. The elastomer diaphragm 204 can be glued to the end cup 203 and also to the sleeve housing 201. The drive-side bearing 105 is installed in a bore in the sleeve housing 201, abutting against an inwardly projecting flange 201a at the drive-side end. The outer bearing raceway 210 is also installed in a bore in the sleeve housing 201, abutting against a shoulder at 214.

[0224] The inner bearing raceway 211 is mounted on the central shaft body 12 and is constrained by the pair of retaining rings 212 to prevent axial movement and separation on the central shaft body.

[0225] A central shaft body 12 (including inner raceways 211) is introduced into the non-drive end of a sleeve housing 201, which carries the set of bearing balls 213 disposed on the bearing raceways 211. A second outer bearing raceway 210 is installed into a bore in the sleeve housing 201, thereby capturing the bearing balls 213 between the four bearing raceways. The central shaft body 12 engages with the bearing 105.

[0226] The non-drive side bearing 106 is installed into a bore in the non-drive side sleeve housing 202, thereby abutting against the inwardly projecting flange 202a at the non-drive side end.

[0227] The non-drive side sleeve housing 202, together with the bearing 106, is positioned on the drive side of the sleeve housing 201 and is axially moved until the shoulder 215 abuts one of the outer bearing raceways 210, thereby forcing the outer raceways into contact with each other. The outer side of the housing 202 fits tightly with the bore in the housing 201. The central shaft body 12 engages with the bearing 106 at the non-drive side end.

[0228] Sleeve assembly 217 is now complete, wherein shaft 12 is carried in a bearing within the bore of the two sleeve portions now connected together.

[0229] Sub-assembly 217 can be installed as a complete item through the drive side end of the spindle housing 9. The end cup 203, now forming part of sub-assembly 217, can be screwed into the thread at the drive side end of a drilled hole in the spindle housing. A cylindrical nose 202b at the non-drive side end of the sleeve passes through the non-drive side end cup 205. A tapered surface 202c formed on the outer side of the sleeve housing 202 engages with a mating tapered surface on the inner side of the tapered washer 207. Lubricant may be present on the adjacent tapered surfaces of the sleeve housing 202 and the tapered washer 207 to reduce frictional resistance to relative rotation as sub-assembly 217 is screwed in. The end cup is screwed in until a suitable level of compressive torque has been reached, introducing the elastomeric ring 206. The assembly may include a locking ring 143 to lock the end cup 203 in a selected position.

[0230] The two now-connected sleeve housings are under compression.

[0231] The central shaft 12 is radially supported by bearings 105 and 106 and can rotate within bearings 105 and 106. These bearings can be ordinary bearings or may include rolling elements, and for this example, needle roller bearings are shown.

[0232] The two halves of the sleeve housing are now secured together in a forward-facing manner by a tapered elastomer ring 206 and a tapered elastomer diaphragm 204, capturing the two outer bearing raceways 210 abutting against each other. The spacing of the retaining rings 212 allows the bearing balls 213 to have running clearance between the four raceways. Any external axial force applied to the central shaft is transmitted by the thrust bearing assembly thus formed to one or the other half of the sleeve housing, and via adjacent end cups into the central shaft housing.

[0233] Once the assembly of the portions within each end is complete and the locking ring is set, a first drive-side mounting structure is provided through the connection of the elastomeric diaphragm 204 and end cup 203 to the central shaft housing. A second non-drive-side mounting structure is provided through the connection of the tapered washer 207, the compliant elastomeric ring 206, and the end cup 205 to the central shaft housing.

[0234] The first mounting structure at the drive side provides a fulcrum 237 tending toward the position shown in the manner equivalent to that explained above for the first example. In fact, the fulcrum 237 tends toward the position shown because this position is also the center of the hemisphere, a portion of which is substantially defined by the conical ring of the elastomer diaphragm 204, and the compressive / tensile strain induced in the elastomer is at a minimum when rotating around this fulcrum.

[0235] The assembly also includes an elastomer washer 227 and an expansion disc 226. The elastomer washer 227 abuts the inner side of the expansion disc 226. The washer 227 can be glued to the disc 226. The disc 226, together with the washer 227, can be pressed onto the nose 202b of the sleeve assembly 217 until the elastomer washer 227 abuts against the end cup 206. The drilled hole in the disc 226 fits snugly into the nose 202b of the sleeve assembly.

[0236] The assembly also includes an expansion chamber 224 and an expansion backplate 223. The expansion chamber 224 is fastened to the expansion backplate 223 with screws 225, capturing the peripheral seal 221. The inner seal 222 axially abuts against the outer surface of the disc 226, further helping to hold the disc 226 in place.

[0237] When the second non-driven side mounting structure is subjected to a radial load in a given direction, a radial displacement in the same direction occurs in the sleeve assembly 217 (including the expansion disc 226 carried on its nose 202b) due to the compliance of the tapered elastomer ring 206. The amount of this displacement is a function of the radial load. This displacement is measured by a sensor.

[0238] For example, Figure 15The diagram illustrates a sensing arrangement for measuring the displacement of the sleeve assembly. This sensing arrangement includes a beam 229 carried within an expansion chamber 224, supported such that its center rests against the outer edge of an expansion disc 226, inducing initial strain in the beam's surface near its center. Any movement of the expansion disc 226 perpendicular to the beam 229 alters the strain in the beam at its center. A strain gauge 230 attached to the beam 229 is connected to a PCB 231. Circuitry (not shown) on the PCB 231 is configured to deliver an electrical signal that consistently indicates the strain in the beam 229. This electrical signal can be used by a controller (not shown) to determine the level of unbalanced lateral forces induced by the rider around the pivot point in a direction perpendicular to the beam 229.

[0239] The sensing arrangement may also include a second beam 232, which can be mounted against different portions of the outer edge of the expansion disc 226 to carry strain gauges 233 also connected to the PCB 231, thereby generating an electrical signal that can be used by the controller to determine the force exerted by the rider perpendicular to the second beam 232. The component may also include a position sensing arrangement for determining the angular position of the center column shaft. This position sensing arrangement includes a ring 234 mounted on the center column shaft 12 and constrained to rotate with it. The ring 234 carries one or more targets 235. A PCB 231 carries one or more sensors 236 that can respond to the passage of the targets as the center column shaft rotates, enabling the controller to determine the angular position of the center column shaft and the cranks 13, 15 attached thereto. Protection for the ring 234 is provided by a circular flange 224a projecting from the expansion housing 224.

[0240] The three examples described herein involve combinations of specific features. Different combinations of the features described above can be used to create feasible embodiments of the invention other than those described.

[0241] As described in the examples above, a drive unit including a motor for providing torque to the bottom bracket axle can be attached to an HPV including any of the bottom bracket assemblies described above. The controller of the drive unit can be configured to calculate, based on a determined lateral force on the bottom bracket axle, the output torque that the motor will apply to the bottom bracket axle when assisting the rider is to be provided and during periods when no assistance from the motor is provided.

[0242] The applicant hereby individually discloses each individual feature described herein, as well as any combination of two or more such features, provided that such features or combinations can be implemented based on the entire specification and in view of the common knowledge of those skilled in the art, regardless of whether such features or combinations of features solve any problem disclosed herein, and without limiting the scope of the claims. The applicant notes that aspects of the invention can consist of any such individual features or combinations of features. In view of the foregoing description, it will be apparent to those skilled in the art that various modifications can be made within the scope of the invention. Claims (as amended under Article 19 of the Treaty) 1. A drive device for HPV, the HPV including and being propelled by the crank assembly, the device comprising: A housing capable of being attached to the HPV; A motor, the motor being carried by the housing; and A drive wheel, located within the housing and connectable to and driven by the motor, is attached to the crank assembly for rotation therewith. The drive wheel has an opening extending through its center, accessible from the opposite side of the housing, thereby allowing the crank on the HPV to pass through the opening for mounting to the drive wheel. The drive wheel is contained within the housing in such a way that it can float radially relative to the housing when not connected to the crank assembly. 2. The drive device of claim 1, wherein the housing includes an internally shaped structure for engaging the drive wheel to retain the drive wheel in a position where it can be accessed from opposite sides of the housing through an opening. 3. The drive device according to claim 2, wherein the internal molding structure is configured to engage the outer edge of the drive wheel. 4. The drive device according to claim 2 or 3, wherein the drive wheel has an axially extending first annular structure, and the internal molding structure includes a second annular structure, the second annular structure being located radially inside or radially outside the first annular structure. 5. The driving device according to claim 4, wherein the second annular structure is located radially inside the first annular structure, and the internal molding structure includes a third annular structure located radially outside the first annular structure. 6. The driving device according to claim 4, wherein the internal molding structure comprises only the second annular structure located radially inside the first annular structure. 7. The drive device according to any of the preceding claims, wherein the housing surrounds the drive wheel circumferentially. 8. The drive device according to any one of claims 1 to 6, wherein the housing extends only partially around the circumference of the drive wheel. 9. The drive device according to any of the preceding claims, comprising a drive belt for connecting the drive wheel to the motor. 10. The drive device according to any of the preceding claims, wherein the drive wheel includes a rim and a plurality of protruding corners extending radially inward from the rim, each protruding corner including a fastening structure, thereby enabling the drive wheel to be directly or indirectly fastened to a crank on the HPV. 11. The drive device according to any of the preceding claims, wherein the drive wheel includes one or more through holes, thereby enabling the drive wheel to be fastened to a crank on the HPV. 12. The drive device according to any of the preceding claims and the HPV including a pedal, wherein the opening of the drive wheel is shaped to allow the pedal of the HPV to pass through the opening. 13. The drive device according to any of the preceding claims, wherein the housing includes a plurality of first mounting structures, thereby enabling the housing to be mounted to the HPV, and at least one of these mounting structures has an electrical conductor for contacting an electrical conductor on the HPV when the drive device is connected to the HPV, for transmitting power between the HPV and the drive device. 14. The drive device and HPV according to any of the preceding claims, wherein the housing of the drive device includes a plurality of first mounting structures, and the HPV includes a plurality of second mounting structures, the first mounting structures and the second mounting structures being configured such that when the drive device is mounted to the HPV and each of the first mounting structures engages with a corresponding one of the second mounting structures, the drive wheel can be positioned such that the central axis of the HPV extends through the center of the drive wheel. 15. The drive device and HPV of claim 14, wherein the HPV has a structural frame including the second mounting structure, and the drive device is configured such that when each of the first mounting structures engages with a corresponding one of the second mounting structures and the drive wheel is positioned such that the central axis of the HPV extends through the center of the drive wheel, the motor of the drive device is positioned closer to the midplane of the frame than the drive wheel. 16. The drive unit and HPV according to claim 14 or 15, wherein at least one of the first mounting structures is located radially outside the outer edge of the drive wheel. 17. The drive device and HPV according to any one of claims 14 to 16, wherein at least one of the first mounting structures is located radially inward of the outer edge of the drive wheel, and the drive wheel defines an access port positioned such that when the center of the drive wheel is located on the central axis of the HPV, it is possible to enter one of the first mounting structures through the port in a direction parallel to the central axis for securing the drive device to the HPV. 18. The drive device and HPV according to any one of claims 14 to 17, wherein the drive device is mounted to the HPV for driving the movement of the HPV, wherein the HPV has a wheel for engaging a power transmission element, the wheel being mounted on the drive side of the HPV about the central axis, and the power transmission element connecting the wheel to the road wheel of the HPV, and the drive wheel being located on the side of the HPV opposite to the drive side. 19. The driving device according to any one of the preceding claims, further comprising: A drive belt that connects the drive wheel to the motor, the drive belt having an offset to employ a curve with a radius larger than that of the drive wheel when tension is released; A tensioner, operable to apply tension to the belt and operable to release tension from the belt; and A guide member for constraining the belt to the outside of the drive wheel along the path along which the belt disengages from the drive wheel. 20. The drive device and central shaft assembly according to any one of claims 1 to 19, wherein the central shaft assembly comprises: A hollow sleeve that carries multiple bearings within its bore to support a central shaft that can rotate within the bearings; the sleeve can be installed into the frame of the HPV. A first mounting structure for the sleeve has elastic resistance to rotation of the sleeve in yaw and roll relative to the frame of the HPV, the elastic resistance being insufficient on its own to prevent the rotation when the central shaft is subjected to unbalanced lateral forces around the first mounting structure, such that the first mounting structure provides a fulcrum for the rotation of the sleeve. A second mounting structure, which, when the sleeve is mounted to the frame of the HPV, is axially displaced from the first mounting structure, and the second mounting structure has compliant drag on the sleeve's rotation in yaw and roll; and One or more sensors are configured to sense radial displacement of the sleeve caused by the rotation of the sleeve about the fulcrum. 21. A method of attaching a drive mechanism according to any one of claims 1 to 20 to an HPV including a crank attached thereto, the method comprising: While the crank remains attached to the HPV, the opening of the drive wheel is fitted over the crank; and subsequently, Secure the drive wheel to the crank. 22. The method of claim 21, wherein the crank carries the pedal, and the method includes: performing a looping step while the pedal is held to be carried by the crank. 23. The method of claim 21 or 22, wherein the overlay step comprises: tilting the drive device relative to the HPV and translating the drive device along the crank.

Claims

1. A drive device for HPV, the HPV including and being propelled by the crank assembly, the device comprising: A housing capable of being attached to the HPV; The motor is carried by the housing; as well as A drive wheel, located within the housing and connectable to and driven by the motor, is attached to the crank assembly for rotation therewith. The drive wheel has an opening extending through its center, accessible from the opposite side of the housing, thereby allowing the crank on the HPV to pass through the opening for mounting to the drive wheel. The drive wheel is contained within the housing in such a way that it can float radially relative to the housing when not connected to the crank assembly.

2. The driving device according to claim 1, wherein, The housing includes an internally shaped structure for engaging the drive wheel to hold the drive wheel in a position where it can be accessed from opposite sides of the housing through an opening.

3. The driving device according to claim 2, wherein, The internal molding structure is configured to engage the outer edge of the drive wheel.

4. The driving device according to claim 2 or 3, wherein, The drive wheel has an axially extending first annular structure, and the internal molding structure includes a second annular structure located radially inside or radially outside the first annular structure.

5. The driving device according to claim 4, wherein, The second annular structure is located radially inside the first annular structure, and the internal molding structure includes a third annular structure located radially outside the first annular structure.

6. The driving device according to claim 4, wherein, The internal molding structure includes only the second annular structure located radially inside the first annular structure.

7. The driving device according to any one of the preceding claims, wherein, The housing surrounds the drive wheel around its circumference.

8. The drive device according to any one of claims 1 to 6, wherein, The housing extends only partially around the circumference of the drive wheel.

9. The drive device according to any of the preceding claims, comprising a drive belt for connecting the drive wheel to the motor.

10. The driving device according to any of the preceding claims, wherein, The drive wheel includes a rim and a plurality of protruding corners extending radially inward from the rim. Each protruding corner includes a fastening structure, thereby enabling the drive wheel to be directly or indirectly fastened to a crank on the HPV.

11. The driving device according to any of the preceding claims, wherein, The drive wheel includes one or more through holes, thereby enabling the drive wheel to be fastened to a crank on the HPV.

12. The drive device according to any of the preceding claims and the HPV including a pedal, wherein, The opening of the drive wheel is shaped to allow the HPV pedal to pass through the opening.

13. The driving device according to any of the preceding claims, wherein, The housing includes a plurality of first mounting structures, thereby enabling the housing to be mounted to the HPV, and at least one of these mounting structures has an electrical conductor that, when the drive unit is connected to the HPV, contacts an electrical conductor on the HPV for transmitting power between the HPV and the drive unit.

14. The drive device and HPV according to any one of the preceding claims, wherein, The housing of the drive unit includes a plurality of first mounting structures, and the HPV includes a plurality of second mounting structures. The first and second mounting structures are configured such that when the drive unit is mounted to the HPV and each of the first mounting structures engages with a corresponding one of the second mounting structures, the drive wheel can be positioned such that the central axis of the HPV extends through the center of the drive wheel.

15. The drive device and HPV according to claim 14, wherein, The HPV has a structural frame including the second mounting structure, and the drive unit is configured such that when each of the first mounting structures engages with a corresponding one of the second mounting structures and the drive wheel is positioned such that the central axis of the HPV extends through the center of the drive wheel, the motor of the drive unit is positioned closer to the midplane of the frame than the drive wheel.

16. The drive device and HPV according to claim 14 or 15, wherein, At least one of the first mounting structures is located radially outside the outer edge of the drive wheel.

17. The drive device and HPV according to any one of claims 14 to 16, wherein, At least one of the first mounting structures is located radially inward of the outer edge of the drive wheel, and the drive wheel defines an access port positioned such that when the center of the drive wheel is located on the central axis of the HPV, it is possible to enter one of the first mounting structures through the port in a direction parallel to the central axis for securing the drive device to the HPV.

18. The drive device and HPV according to any one of claims 14 to 17, wherein, The drive unit is mounted to the HPV for driving the movement of the HPV, wherein the HPV has wheels for engaging a power transmission element, the wheels are mounted on the drive side of the HPV around the central axis, and the power transmission element connects the wheels to the road wheels of the HPV, and the drive wheels are located on the side of the HPV opposite to the drive side.

19. The driving device according to any one of the preceding claims, further comprising: A drive belt that connects the drive wheel to the motor, the drive belt having an offset to employ a curve with a radius larger than that of the drive wheel when tension is released; A tensioner, operable to apply tension to the belt and operable to release tension from the belt; as well as A guide member for constraining the belt to the outside of the drive wheel along the path along which the belt disengages from the drive wheel.

20. The drive device and central shaft assembly according to any one of claims 1 to 19, wherein the central shaft assembly comprises: A hollow sleeve that carries multiple bearings within its bore to support a central shaft that can rotate within the bearings; the sleeve can be installed into the frame of the HPV. A first mounting structure for the sleeve has elastic resistance to rotation of the sleeve in yaw and roll relative to the frame of the HPV, the elastic resistance being insufficient on its own to prevent the rotation when the central shaft is subjected to unbalanced lateral forces around the first mounting structure, such that the first mounting structure provides a fulcrum for the rotation of the sleeve. A second mounting structure, which is axially displaced from the first mounting structure when the sleeve is mounted to the frame of the HPV, has compliant resistance to rotation in yaw and roll of the sleeve. as well as One or more sensors are configured to sense radial displacement of the sleeve caused by the rotation of the sleeve about the fulcrum.

21. A method of attaching a drive mechanism according to any one of claims 1 to 20 to an HPV including a crank attached thereto, the method comprising: While the crank remains attached to the HPV, the opening of the drive wheel is fitted over the crank; And subsequently, Secure the drive wheel to the crank.

22. The method according to claim 21, wherein, The crank carries the pedal, and the method includes performing a looping step while the pedal is held to be carried by the crank.

23. The method according to claim 21 or 22, wherein the application step comprises: The drive unit is tilted relative to the HPV and the drive unit is translated along the crank.

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