GB2555651A

GB2555651A - Electric vehicle with improved drive assembly

Info

Publication number: GB2555651A
Application number: GB1618823.7A
Authority: GB
Inventors: Bingham John
Original assignee: Ricardo UK Ltd
Current assignee: Ricardo UK Ltd
Priority date: 2016-11-08
Filing date: 2016-11-08
Publication date: 2018-05-09

Abstract

An electric vehicle, comprising a wheel mounting assembly (138, see fig. 3) configured for the attachment of a wheel, a motor 102 for providing drive to the wheel mounting assembly and a suspension assembly 106 for supporting the vehicle with respect to the wheel when attached to the wheel mounting assembly, in use, wherein the motor is located on the suspension assembly at a position remote from the wheel mounting assembly. The electric vehicle may include a transmission assembly for transferring drive between the motor and the wheel mounting assembly. The suspension assembly may comprise an upper and lower part with a central part extending between said upper and lower part. The suspension assembly may further comprise a motor control part for maintaining alignment, which may be a single or double wishbone element. Said upper, lower and motor control part may share a common instant centre for maintaining alignment.

Description

(54) Title of the Invention: Electric vehicle with improved drive assembly

Abstract Title: Electric vehicle with a motor located remotely from wheel mounting assembly (57) An electric vehicle, comprising a wheel mounting assembly (138, see fig. 3) configured for the attachment of a wheel, a motor 102 for providing drive to the wheel mounting assembly and a suspension assembly 106 for supporting the vehicle with respect to the wheel when attached to the wheel mounting assembly, in use, wherein the motor is located on the suspension assembly at a position remote from the wheel mounting assembly. The electric vehicle may include a transmission assembly for transferring drive between the motor and the wheel mounting assembly. The suspension assembly may comprise an upper and lower part with a central part extending between said upper and lower part. The suspension assembly may further comprise a motor control part for maintaining alignment, which may be a single or double wishbone element. Said upper, lower and motor control part may share a common instant centre for maintaining alignment.

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Figure 1

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Figure 2

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Figure 3

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Figure 4

Electric vehicle with improved drive assembly

FIELD OF THE INVENTION

The present invention relates to improvements in electric vehicles and drive assemblies for electric vehicles.

BACKGROUND OF THE INVENTION

Motors for powering the motion of electric vehicles have traditionally been located at a central position within the vehicle (for example, in the boot or under-bonnet space), wherein their mass forms part of the 'sprung' mass of the vehicle. Such an arrangement can afford the vehicle with improved handling characteristics, such as ease of steering and ride comfort. A problem of such arrangements is that less space is available within the vehicle for other apparatus, such as battery packs, or for passengers and their luggage.

Providing a motor in an 'in-wheel' location can help to overcome this problem. However, the mass of the motor thereby contributes to the un-sprung mass of the vehicle, which can lead to decreased ease of handling, reduced ride comfort and increased steering offset. In addition, issues regarding the location of associated braking apparatus can arise.

In order to address these issues, it is known to locate the motor in a position close to, but remote from the wheel. For example, US2009/0133944 and US7243749 disclose the location of the motor on a damper of the associated suspension assembly. However, these known approaches have further disadvantages, such as a reduced ability for the damper to attenuate resonant frequencies within the suspension assembly, further reducing the ride comfort offered by the vehicle.

The present invention seeks to overcome or at least mitigate / alleviate one or more problems associated with the prior art.

SUMMARY OF THE INVENTION

A first aspect of the invention provides an electric vehicle, comprising: a wheel mounting assembly configured for the attachment of a wheel, a motor for providing drive to the wheel mounting assembly (e.g. for providing rotational drive for a wheel attached to the wheel mounting assembly); and a suspension assembly for supporting the vehicle with respect to a wheel when attached to the wheel mounting assembly, in use (i.e. it will be understood that the wheel mounting assembly is configured for the attachment of a wheel, and defines an axis of rotation for said wheel under drive from the motor); wherein the motor is located on the suspension assembly at a position remote from the wheel mounting assembly.

Providing the motor at a position away from an in-board location advantageously means that valuable vehicle space is available for passengers or their luggage, and especially in the case of an electric vehicle- more space is available for battery units or charging apparatus.

In addition, providing the motor in a position remote from the wheel mounting assembly means that a significant reduction in the un-sprung mass effect is achievable in comparison to a traditional wheel mounted motor. This advantageously results in improved vehicle steering and handling, especially under conditions of braking or acceleration, and greatly improved ride comfort in comparison to an in-wheel motor. This also allows conventional steering off-sets to be utilised, rather than the increased off-set required should the motor be located in-wheel. Increased steering off-sets increases the effort required from a driver to steer the vehicle. A reduced steering offset advantageously limits the impact that uneven road surfaces, and braking and acceleration forces have on the ease with which the vehicle can be steered, making it easier for the driver to control the direction of the vehicle.

Further, locating the motor on the suspension assembly allows for a conventional friction brake package to be utilised with an attached wheel. This advantageously permits the use of existing components and reduces the costs associated with the development and manufacture of a bespoke braking apparatus.

In exemplary embodiments, a transmission assembly is provided, extending between the motor and the wheel mounting assembly, for transferring drive between the motor and the wheel mounting assembly. Such an arrangement allows the driving force generated by the motor to be transmitted directly to an attached wheel, advantageously reducing the distance across which said driving force needs to be transmitted (compared with centrally located motors, for example).

In exemplary embodiments, the suspension assembly further comprises an upper part, a lower part and a central part extending between the upper part and the lower part.

In exemplary embodiments, the suspension assembly further comprises a motor control part for maintaining an alignment of the motor with respect to a wheel when attached to the wheel mounting assembly, in use.

In exemplary embodiments, the motor is pivotably mounted (e.g. by an upper end of the motor) to the motor control part.

Maintaining alignment of the motor with respect to an attached wheel ensures that impact stresses imparted on the wheel and transferred to the suspension assembly during normal day-to-day operation of the vehicle advantageously do not interrupt the constant transmission of drive between the motor and the wheel attachment assembly.

In exemplary embodiments, the motor control part is a wishbone element of the suspension assembly.

Advantageously, a wishbone provides a low-complexity, readily available (and so low-cost) component for maintaining alignment of the motor with respect to an attached wheel.

In exemplary embodiments the upper part, the lower part and the motor control part share a common instant centre. The upper part and the lower part having the same instant centre provides for the alignment of a wheel attached to the wheel mounting assembly to be maintained with respect to the vehicle when the suspension assembly flexes during normal use. This reduces wear and tear on the wheel, and reduces the risk of damage being inflicted. The motor control part is arranged so as to share a common instant centre with the upper part and the lower part, which in turn provides for the alignment of the motor with respect to a wheel attached to the wheel mounting assembly to be maintained.

Advantageously, when the arrangement of the motor control part is such that the motor control part has the same instant centre as the upper and lower parts of the suspension assembly, changes in angle of the transmission assembly with respect to the motor and the wheel are minimised, which reduces the likelihood of torque steer in use.

In exemplary embodiments, the lower part is the lower wishbone of a double wishbone suspension assembly.

In exemplary embodiments, the upper part is the upper wishbone of a double wishbone suspension assembly.

Double wishbone suspension assemblies are commonplace on modem road vehicles. Advantageously, this means that a readily available suspension assembly may be modified to accommodate the motor and transmission assembly, in turn reducing manufacturing or procurement costs.

In exemplary embodiments, the transmission assembly comprises a drive shaft, and wherein said drive shaft has a centre of rotation.

In exemplary embodiments, a first end of the transmission assembly is rotatably coupled to the motor.

In exemplary embodiments, a second end of the transmission assembly is rotatably coupled to the wheel mounting assembly

The transmission assembly comprises a drive shaft which extends between the motor and the wheel mounting assembly. The drive shaft is rotatably coupled to the motor such that rotation of an output shaft of the motor is transferred directly to drive shaft which itself has a centre of rotation. The drive shaft rotates around a longitudinal axis and transfers the rotational output of the motor to the wheel mounting assembly. The transmission assembly therefore has an advantageously compact form, which means that less space is required to mount and house the components. In addition, the close proximity of the wheel mounting assembly, and as such an attached wheel, to the transmission assembly and therefore the motor, permits the use of conventional steering off-sets. The use of a reduced steering off-set in comparison to the increased off-set required when the motor is located in-wheel, limits the impact that uneven road surfaces, and braking and acceleration forces have on the ease with which the vehicle can be steered, making it easier for the driver to control the direction of the vehicle.

In exemplary embodiments, the first end of the transmission assembly is rotatably coupled to the motor by virtue of a first constant velocity joint. This permits the driving force generated by the motor to be continuously transmitted to a wheel via the transmission assembly, whilst allowing for axial displacement of the rotatable output of the motor with respect to the drive shaft of the transmission assembly, and of the drive shaft of the transmission assembly with respect to the wheel mounting assembly. Such displacement may occur upon movement of the suspension assembly

In exemplary embodiments, the vehicle further comprises a motor bearing and wherein the first constant velocity joint is located within said motor bearing. This configuration allows a greater distance between the first CV joint and a second CV joint to be provided. This enables joint angles to be minimised, which, in turn, advantageously reduces torque steer.

In exemplary embodiments, the second end of the transmission assembly is rotatably coupled to the wheel mounting assembly by virtue of a second constant velocity joint.

This permits the driving force generated by the motor to be continuously transmitted to an attached wheel via the transmission assembly, whilst allowing for axial displacement of the rotatable output of the motor with respect to the drive shaft of the transmission assembly, and of the drive shaft of the transmission assembly with respect to the wheel mounting assembly. Such displacement may occur upon movement of the suspension assembly. In exemplary embodiments, wherein the central part comprises a knuckle bearing and wherein the second constant velocity joint is located within said knuckle bearing.

In exemplary embodiments, the central part is the knuckle of a double wishbone suspension assembly.

Double wishbone suspension assemblies are commonplace on modem road vehicles. The central part may be a knuckle that may require little or no modification to allow the mounting of the motor to the suspension assembly. Advantageously, this means that a readily available suspension assembly may be modified to accommodate the motor and transmission assembly, in turn reducing manufacturing or procurement costs.

In exemplary embodiments, an output shaft of the motor and the drive shaft of the transmission assembly share a common centre of rotation with a wheel when attached to the wheel mounting assembly, in use.

Ensuring that the centres of rotation of the output shaft of the motor and the drive shaft of the transmission assembly remain aligned as far as possible, ensures that the driving force generated by the motor is transferred as efficiently as possible, via the transmission assembly to the wheel mounting assembly, and as such, an attached wheel. This configuration advantageously reduces the demand placed on the motor, and as such, may improve operational efficiency. In turn, undue stresses acting on the components of the transmission assembly can be reduced, reducing the likelihood of their subsequent premature wear or failure.

In exemplary embodiments, the motor is pivotably mounted to the lower part of the suspension assembly. Advantageously, this configuration provides for a greater level of control over movement of the motor, as a wider pivot spacing for the motor mounting is achievable.

In exemplary embodiments, the motor is pivotably mounted to the upper part of the suspension assembly. This provides for a more advantageous motion ratio, which in turn reduced the contribution of the mass of the motor to the unsprung mass effect. As a result, the overall unsprung mass effect is advantageously reduced.

In exemplary embodiments, the lower part comprises a first arm and a second arm, and wherein the motor is pivotably attached at a first attachment point to the first arm, and the motor is pivotably attached at a second attachment point to the second arm. In exemplary embodiments, a lower end of the motor is pivotably attached to the first attachment point, and the lower end of the motor is also pivotably attached to the second attachment point.

Allowing the motor to pivot with respect to the lower part of the suspension assembly Advantageously ensures that centres of rotation of the output shaft of the motor, the drive shaft of the transmission assembly and a wheel attached to the wheel mounting assembly may remain aligned as far as possible. This is especially important during movement of the suspension assembly during normal use, to prevent undue stresses acting on the components and their subsequent premature wear or failure.

In exemplary embodiments, the first attachment point is located substantially halfway along the length of the first arm, and wherein the second attachment point is located substantially halfway along the length of the second arm.

Advantageously, this means that un-sprung mass effects, such as decreased ease of vehicle steering and level of ride comfort are minimised as far as possible.

In exemplary embodiments, the upper part, the lower part and the motor control part are pivotably mounted to the vehicle.

In exemplary embodiments, the electric vehicle comprises at least one front wheel and at least one rear wheel, and wherein the wheel mounting assembly is configured for the attachment of the at least one front wheel.

A second aspect of the invention provides a drive assembly for an electric vehicle, comprising: a suspension assembly having a first end configured for the attachment of a wheel, and a motor for providing drive to said wheel, wherein the motor is located on the suspension assembly in a position remote from the first end, and wherein a transmission assembly is provided for transferring drive between the motor and the first end of the suspension assembly.

A third aspect of the invention provides an electric vehicle, comprising: a wheel mounting assembly, a motor for providing drive to the wheel mounting assembly; and a suspension assembly for supporting the vehicle with respect to a wheel when attached to the wheel mounting assembly, in use, wherein the motor is located in a position remote from the wheel mounting assembly, wherein a transmission assembly comprising a drive shaft is provided for transferring drive between the motor and the wheel mounting assembly, wherein the drive shaft has a centre of rotation and further wherein an output shaft of the motor and the drive shaft of the transmission assembly share a common axis of rotation with a wheel when attached to the wheel mounting assembly, in use.

Providing the motor in a position away from an in-board location advantageously means that valuable vehicle space is available for passengers or their luggage, and especially in the case of an electric vehicle, more space is available for battery units or charging apparatus.

In addition, providing the motor in a position remote from the wheel mounting assembly means that a significant reduction in the un-sprung mass effect is achievable in comparison to a traditional wheel mounted motor. This advantageously results in improved vehicle steering and handling, especially under conditions of braking or acceleration, and greatly improved ride comfort in comparison to an in-wheel motor. This also allows conventional steering off-sets to be utilised, rather than the increased off-set required should the motor be located in-wheel. Increased steering off-sets 7 increases the effort required from a driver to steer the vehicle. A reduced steering offset advantageously limits the impact that uneven road surfaces, and braking and acceleration forces have on the ease with which the vehicle can be steered, making it easier for the driver to control the direction of the vehicle.

Ensuring that the centres of rotation of the output shaft of the motor and the drive shaft of the transmission assembly remain aligned as far as possible, ensures that the driving force generated by the motor is transferred as efficiently as possible, via the transmission assembly to the wheel mounting assembly. This configuration advantageously reduces the demand placed on the motor, and as such, may improve operational efficiency. In turn, undue stresses acting on the components of the transmission assembly can be reduced, reducing the likelihood of their subsequent premature wear or failure.

In exemplary embodiments, the suspension assembly further comprises a motor control part for maintaining an alignment of the motor with respect to a wheel when attached to the wheel mounting assembly in use.

Tn exemplary embodiments, the second end of the transmission assembly is rotatably coupled to the wheel mounting assembly by virtue of a second constant velocity joint.

In exemplary embodiments, an output shaft of the motor and the drive shaft of the transmission assembly share a common centre of rotation with a wheel when attached to the wheel mounting assembly in use.

Advantageously, this means that un-sprung mass effects, such as decreased case of vehicle steering and level of ride comfort are minimised as far as possible.

In exemplary embodiments, the vehicle comprises at least one front wheel and at least one rear wheel, and wherein the wheel mounting assembly is configured for the attachment of the at least one front wheel.

A fourth aspect of the invention provides a drive assembly for an electric vehicle, comprising; a suspension assembly having a first end configured for the attachment of a wheel and a motor for providing drive to said wheel, wherein the motor is located on the suspension assembly in a position remote from the first end, and wherein a transmission assembly comprising a drive shaft is provided for transferring drive between the motor and the first end of the suspension assembly, wherein the drive shaft has a centre of rotation and further wherein an output shaft of the motor and the drive shaft of the transmission assembly share a common axis of rotation with a wheel when attached to the first end of the suspension assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a front perspective view of an embodiment of the invention.

Figure 2 is a rear perspective view of the embodiment of Figure 1.

Figure 3 is a cross sectional view of the embodiment of Figure 1.

Figure 4 is a cross sectional view of the embodiment of Figure 1, illustrating the common instant centre of the upper part, the lower part and the motor control part.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Referring firstly to Figure 1, a suspension mounted motor assembly for an electric vehicle is indicated generally at 100.

In the described embodiment, the assembly includes: a motor 102, for generating a driving force, a transmission assembly 104, for transmitting the driving force generated by the motor 102 in order to propel the vehicle; and a suspension assembly 106, configured to support the motor 102 and the transmission assembly 104.

The suspension assembly 106 includes an upper part 108, a lower part 110 and a central part 112 which extends between the upper part 108 and the lower part 110.

In the described embodiment, the upper part 108 is the upper wishbone, the lower part 110 is the lower wishbone and the central part 112 is the knuckle of a double wishbone suspension assembly. The lower part 110 may be a standard lower wishbone modified to allow the motor 102 to be pivotally mounted, whilst the upper part 108 and the central part 112 may be an upper wishbone and a knuckle respectively that may require little or no modification to allow the mounting of the motor 102. Advantageously, this means that a readily available suspension assembly may be modified to accommodate the motor 102 and transmission assembly 106. This may ultimately allow the vehicle manufacturer to reduce manufacturing or procurement costs.

In the described embodiment, the motor 102 is mounted to the lower part 110 of the suspension assembly 106. This offers multiple advantages over either mounting the motor 102 within an attached wheel, or the spring damper of a suspension coil. For example, the un-sprung mass of a vehicle can be significantly reduced. This results in improved vehicle steering and handling, especially under conditions of braking or acceleration. This both improves both vehicle safety and the level of ride comfort offered.

In addition, this allows a vehicle to be configured with conventional steering off-sets, rather than the increased off-set that would be required should the motor be located 'in-wheel'. Increased steering off-sets increases the effort required from a driver to steer the vehicle. A reduced steering offset advantageously limits the impact that uneven road surfaces, and braking and acceleration forces have on the ease with which the vehicle can be steered, making it easier for the driver to control the direction of the vehicle.

Further, mounting the motor to a lower part of the suspension assembly allows for a conventional friction brake package to be utilised. This may in turn simplify, and reduce the costs associated with, the manufacturing process. Finally, re-siting the motor away from an in-board location means that valuable vehicle space is available for passengers or their luggage, or in the case of an electric vehicle, more space is available for battery units or charging apparatus.

In alternative embodiments, the motor may be mounted to a lower control arm (FCA) of a suspension assembly. Alternatively, the motor may be mounted to an upper wishbone or an upper control arm (UCA). In addition, the assembly may be incorporated within a high arm double wishbone, strut or multilink suspension system.

In the described embodiment, the motor 102 is pivotably mounted to the lower part 110 of the suspension assembly 106. Referring to Figure 2, the lower part 110 defines an Ά-shape', having first and second arms 114, which in the described embodiment, are substantially identical mirror images of one another. The first and second arms 114 extend and diverge away from an apex 118, which also defines the apex of the Άshape'. The apex 118 of the lower part 110 is pivotably connected to a lower end 120 of the central part 112.

The lower end of the motor 102 is pivotably attached to the first and second arms 114 of the lower part 110 at substantially identical first and second attachment points 116 respectively. This configuration allows the motor 102 to pivot with respect to the lower part 110. In the described embodiment, the first and second attachment points are conventional elastomer bushings. The use of such bushings advantageously provides additional motor noise isolation. However, in alternative embodiments, the first and second attachment points may be any coupling suitable for allowing the motor to pivot with respect to the lower part 110.

Allowing the motor 102 to pivot with respect to the lower part 110 of the suspension assembly 106 advantageously ensures that the centres of rotation of an output shaft of the motor 102, a drive shaft of the transmission assembly 104 and a wheel (not shown) remain aligned as far as possible. This is especially important during movement of the suspension assembly during normal use, to prevent undue stresses acting on the components and their subsequent premature wear or failure.

The first and second attachment points 116 are located substantially halfway along the length of the first and second arms 114 respectively. Locating the motor 102 substantially halfway along the length of the lower wishbone ensures that the motor 102 is provided in a location in-board of the wheel, leading to a decrease in un-sprung mass effects. As a result, the ease with which the vehicle can be steered, and the subsequent level of ride comfort offered can be greatly improved.

An upper end of the motor 102 is pivotably mounted to a motor control part 122 at a third attachment point 126, by virtue of a conventional elastomer bushing. The use of such a bushing advantageously provides additional motor noise isolation. In the described embodiment, the motor control part 122 also substantially defines an Άshape'. The motor control part 122 has first and second arms 124, which are substantially identical mirror images of one another. The first and second arms 124 extend and diverge away from an apex 128, which also defines the apex of the Άshape'. The apex 128 of the motor control part 122 is pivotably mounted to the motor 102.

The motor control part 122 provides for the position of the motor 102 to be stabilised with respect to the suspension assembly 106. Advantageously, the motor control part

122 is pivotably connected to the motor 102, this further ensures that the centres of rotation of the output shaft of the motor 102, the drive shaft of the transmission assembly 104 and an attached wheel remain aligned as far as possible.

In the described embodiment, the motor control part 122 is a wishbone. In alternative embodiments, the motor control part may be an upper control arm (UCA). Further, the third attachment point of the motor may be any coupling suitable for allowing the motor to pivot with respect to the motor control part. In a yet further alternative embodiment, the motor may be mounted to the upper wishbone (or an upper control arm - UCA) with a separate motor lower wishbone (or lower control arm - LCA).

Referring now to Figure 3, the transmission assembly 104 is arranged between the motor 102 and the central part 112. Such an arrangement allows the driving force generated by the motor 102 to be transmitted directly to a vehicle wheel, whilst the overall size of the assembly 100 is minimised. Providing a more compact suspension mounted motor assembly 100 advantageously allows said assembly 100 to be mounted within a vehicle with a minimum of modification to the vehicle required. As such, the production or assembly process and the associated costs can be minimised.

A first end 130 of the transmission assembly 104 is rotatably coupled to an output shaft output 132 of the motor 102. The transmission assembly includes a drive shaft 134 that extends between the first end 130 and a second end 136. The output shaft 132 and the drive shaft 134 of the transmission assembly 104 are configured to share a common centre of rotation, which is maintained as far as possible during pivoting of the motor about the pivotable mount between the motor and the lower part. The common centre of rotation is maintained during normal operation of the assembly 100, wherein deflection of an attached wheel by an uneven road surface causes pivoting of the upper part 108 and the lower part 110 with respect to a vehicle chassis, by the provision for the motor 102 to pivot with respect to the lower part 110.

Ensuring that the centres of rotation of the output shaft 132 of the motor 102 and the drive shaft 134 of the transmission assembly 104 remain aligned as far as possible, ensures that the driving force generated by the motor 102 is transferred as efficiently as possible, via the transmission assembly 104 to an attached wheel. This configuration advantageously reduces the demand placed on the motor 102, and as such, may improve operational efficiency. In turn, undue stresses acting on the components of the transmission assembly 104 can be reduced, reducing the likelihood of their subsequent premature wear or failure.

When the assembly 100 is mounted to a vehicle and is in use, the motor 102 would be located in close proximity to an attached wheel. As a result, the drive shaft of the transmission assembly is comparatively short. The described configuration also allows drive shaft angles to be minimised, thus minimising unwanted steering effects such as torque steer. This is an important consideration due to the relatively short length of the drive shaft 134, as reducing the length of the driveshaft means that said shaft will undergo a greater change in driveshaft angle for any given amount of vertical suspension travel.

Referring again to Figure 3, the central part 112 includes a wheel mounting assembly 138, configured to allow a wheel to be attached to the suspension assembly 106. The second end 136 of the transmission assembly 104 is rotatably coupled to a first end 140 of the wheel mounting assembly 138. A second end 142 of the wheel mounting assembly 138 is configured for the mounting of a wheel (not shown). In the described embodiment, the wheel mounting assembly 138 is the suspension upright or steering knuckle. This configuration allows for a wheel to be directly mounted to the suspension assembly 106. Advantageously, the close proximity of said wheel to the transmission assembly 104, and as such, the motor 102, permits the use of conventional steering off-sets. The use of a reduced steering off-set in comparison to the increased off-set required when the motor 102 is located in-wheel, limits the impact that uneven road surfaces, and braking and acceleration forces have on the ease with which the vehicle can be steered, making it easier for the driver to control the direction of a vehicle.

The central part 112 of the suspension assembly 106 has an aperture 144, in which the wheel mounting assembly 138 is itself mounted. The wheel mounting assembly 138 is mounted within the aperture 144 such that the first end 140 protrudes from a rear side of the central part 112, and the second end 142 protrudes from a front side of the central part 112. This configuration allows the central part 112 to act as a support for the wheel mounting assembly 138, such that advantageously, no additional or more17 complex components are required to support the wheel mounting assembly 138 with respect to the suspension assembly 106.

With further reference to Figure 3, the first end 130 of the transmission assembly 104 is rotatably coupled to the motor 102 by virtue of a first constant velocity joint 146, located within a motor bearing 148. In addition the second end 136 of the transmission assembly 104 is rotatably coupled to the first end 140 of the wheel mounting assembly 138 by virtue of a second constant velocity joint 150, located within a knuckle bearing 152.

This configuration permits the driving force generated by the motor 102 to be continuously transmitted to a wheel mounted to the second end 142 of the wheel mounting assembly 138 via the transmission assembly 104, whilst allowing for axial displacement of the rotatable output 132 of the motor 102 with respect to the drive shaft 134 of the transmission assembly 104, and of the drive shaft 134 of the transmission assembly 104 with respect to the wheel mounting assembly 138. Such displacement may occur upon larger deflections of the suspension assembly 106, for example, when an attached wheel comes into contact with a particularly uneven road surface. The first constant velocity joint 146 is arranged to be geometrically aligned with the second constant velocity joint 148, such that they share a common arc. Consequently, this configuration allows the motor and the steering knuckle 138 to move on the same arc (i.e. about the same instant centre), which advantageously means that the change in driveshaft angle can be minimised, in turn reducing unwanted steering effects.

The second end 142 of the wheel mounting assembly 138 may further be configured for the attachment of friction braking apparatus (not shown). The configuration of the suspension mounted motor assembly 100 provides for a conventional friction brake package to be utilised employed. This means that advantageously, the processes of manufacturing and maintaining the assembly can be simplified, resulting in a reduction in the associated costs. Alternatively, the friction braking apparatus may be mounted to the motor 102. Advantageously, this would provide greater scope for the packaging of steering ball joints within the assembly.

With reference to Figures 2 and 3, the lower end 120 of the central part 112 is pivotably connected to the apex of the lower part 118. An upper end 154 of the central part 112 is pivotably connected to the upper part 108. In the described embodiment, the upper part 108, the lower part 110 and the motor control part 122 are configured to be pivotably mounted to the chassis of a vehicle. Providing for each part to individually pivotably mount to the chassis of a vehicle ensures that in use, the mechanical stability of the suspension mounted motor assembly 100 is maximised, whilst a high level of control of the position of the motor 102 during pivoting of the suspension assembly 106 is ensured.

Referring now to Figure 4, the upper part 108, the lower part 110 and the motor control part 122 share a common instant centre 154. As the geometry of the motor control part 122 has the same instant centre as the upper part 108 and the lower part 110 of the suspension assembly 106, any changes in the angle of components of the transmission assembly 104 (i.e. the first constant velocity joints 146 and/or the second constant velocity joint 150) will be minimised. This decreases the likelihood that a vehicle will experience torque steer as a result of the output of the motor 102.

In the described embodiment, the assembly 100 is configured to be included as part of the suspension apparatus of the front wheel of an electric vehicle. In alternative embodiments the assembly may be configured to be included as part of the suspension apparatus of a front wheel of a non-electric vehicle, or the rear wheel of an electric vehicle or non-electric vehicle as appropriate.

Throughout the description and claims of this specification, the words comprise and contain and variations of the word, for example comprising and comprises, means including, but not limited to, and it is not intended to (and does not) exclude other moieties, components, integers or steps.

Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics or compounds described in conjunction with a particular aspect, embodiment or example of the invention are to be understood as be applicable to any other aspect, embodiment or example described herein unless incompatible therewith.

Claims

1. An electric vehicle, comprising:

a wheel mounting assembly configured for the attachment of a wheel; a motor for providing drive to the wheel mounting assembly; and a suspension assembly for supporting the vehicle with respect to a wheel when attached to the wheel mounting assembly, in use, wherein the motor is located on the suspension assembly at a position remote from the wheel mounting assembly.

2. The electric vehicle of claim 1, wherein a transmission assembly is provided for transferring drive between the motor and the wheel mounting assembly.

3. The electric vehicle of any of claim 1 or claim 2, wherein the suspension assembly further comprises an upper part, a lower part and a central part extending between the upper part and the lower part.

4. The electric vehicle of claim 3, wherein the suspension assembly further comprises a motor control part for maintaining an alignment of the motor with respect to a wheel when attached to the wheel mounting assembly in use.

5. The electric vehicle of claim 4, wherein the motor is pivotably mounted to the motor control part.

6. The electric vehicle of any of claim 4 or claim 5, wherein the motor control part is a wishbone element.

7. The electric vehicle of any of claims 4 to 6, wherein the upper part, the lower part and the motor control part share a common instant centre for maintaining the alignment of the motor with respect to a wheel when attached to the wheel mounting assembly, in use..

8. The electric vehicle of any of claims 3 to 7, wherein the lower part is the lower wishbone of a double wishbone suspension assembly.

9. The electric vehicle of any of claims 3 to 8, wherein the upper part is the upper wishbone of a double wishbone suspension assembly.

10. The electric vehicle of any of claims 2 to 9, wherein the transmission assembly comprises a drive shaft, and wherein said drive shaft has a centre of rotation.

11. The electric vehicle of claim 10, wherein a first end of the transmission assembly is rotatably coupled to the motor.

12. The electric vehicle of claim 10 or claim 11, wherein a second end of the transmission assembly is rotatably coupled to the wheel mounting assembly.

13. The electric vehicle of claim 11, wherein the first end of the transmission assembly is rotatably coupled to the motor by virtue of a first constant velocity joint.

14. The electric vehicle of claim 13, wherein the vehicle further comprises a motor bearing, and wherein the first constant velocity joint is located within said motor bearing.

15. The electric vehicle of claim 12, wherein the second end of the transmission assembly is rotatably coupled to the wheel by virtue of a second constant velocity joint.

16. The electric vehicle of claim 15, wherein the central part comprises a knuckle bearing and wherein the second constant velocity joint is located within said knuckle bearing.

17. The electric vehicle of claim 16, wherein the central part is the knuckle of a double wishbone suspension assembly.

18. The electric vehicle of any of claims 10 to 17, wherein an output shaft of the motor and the drive shaft of the transmission assembly share a common center of rotation with a wheel when attached to the wheel mounting assembly, in use.

19. The electric vehicle of any of claims 3 to 18, wherein the motor is pivotably mounted to the lower part of the suspension assembly

20. The electric vehicle of any of claims 3 to 18, wherein the motor is pivotably mounted to the upper part of the suspension assembly

21. The electric vehicle of claim 19, wherein the lower part comprises a first arm and a second arm, wherein the motor is pivotably attached at a first attachment point to the first arm, and wherein the motor is pivotably attached at a second attachment point to the second arm.

22. The electric vehicle of claim 21, wherein a lower end of the motor is pivotably attached to the first attachment point, and wherein the lower end of the motor is also pivotably attached to the second attachment point.

23. The electric vehicle of claim 22, wherein the first attachment point is located substantially halfway along the length of the first arm, and wherein the second attachment point is located substantially halfway along the length of the second arm.

24. The electric vehicle of any of claims 3 to 23, wherein the upper part, the lower part and the motor control part are pivotably mounted to the vehicle.

25. The electric vehicle of any preceding claim, wherein the vehicle comprises at least one front wheel and at least one back wheel, and wherein the wheel mounting assembly is configured for the attachment of the at least one front wheel.

26. A drive assembly for an electric vehicle, comprising: a suspension assembly having a first end configured for the attachment of a wheel and a motor for providing drive to said wheel, wherein the motor is located on the suspension assembly at a position remote from the first end, and wherein a transmission assembly is provided for transferring drive between the motor and the first end of the suspension assembly.

27. An electric vehicle, comprising:

a wheel mounting assembly configured for the attachment of a wheel, a motor for providing drive to the wheel mounting assembly; and a suspension assembly for supporting the vehicle with respect to a wheel when attached to the wheel mounting assembly, in use.

wherein the motor is located in a position remote from the wheel mounting assembly, wherein a transmission assembly comprising a drive shaft is provided for transferring drive between the motor and the wheel mounting assembly, wherein the drive shaft has a center of rotation and further wherein an output shaft of the motor and the drive shaft of the transmission assembly share a common center of rotation with a wheel when attached to the wheel mounting assembly in use.

Intellectual

Property

Office

Application No: GB1618823.7