Patent Application
20220402559
The present disclosure relates to a zero emission vehicle, such as an electric or fuel cell van, bus or car, with a skateboard platform or skateboard chassis and a body. The term ‘skateboard platform or skateboard chassis’ should be expansively construed to cover any vehicle chassis or underbody in which the power train is low and substantially flat (e.g. there is a low and flat electric battery pack or fuel cell, and there are compact electric traction motors as opposed to a bulky internal combustion engine, and there are drive-by-wire accelerator, brakes and steering systems. Skateboard platforms are widely used in the electric vehicle sector; very different bodies can be readily designed to sit on the same skateboard platform, since the skateboard platform imposes far fewer requirements on the design of the external body shell and the internal configuration of everything inside the body, compared to conventional, monocoque vehicle platforms. The battery pack in a skateboard platform can provide or substantially contribute to the structural integrity of the platform; alternatively, the battery pack can be enclosed within and be supported by an external rigid structure.
In designing electric vehicles, established automotive manufacturers often carry over engineering thinking from their experience of conventional vehicles powered by internal combustion engines (ICEs). This makes sense. These large manufacturers have spent many years and often billions of dollars in the research and development of methodologies, technologies and components for these conventional vehicles. Many of them have been hugely successful in this. Reusing that work when developing and manufacturing electric vehicles is therefore less expensive and quicker than doing this all again. This approach is encouraged by having have workforces of tens or hundreds of thousands of people, established R&D centres and vast manufacturing facilities that for years have been focussed on optimising the design and manufacture of these conventionally powered vehicles.
There are however problems with this. Engineering thinking and technologies that are optimised for vehicles powered by ICEs are not necessarily optimised for electric vehicles. The different powertrains have different characteristics. By using engineering thinking in an electric vehicle that is optimised for the legacy ICE powertrain, the resulting vehicle will almost inevitably be much like the vehicle it seeks to replace. It will not make full use of the characteristics of the electric powertrain. It will not be optimised.
International Application No. PCT/GB2018/052415 describes one area in which established, legacy thinking has been resisted and, instead, fresh thinking has been brought to the design of electric vehicles. (The technology described in that application was developed by the same organisation as the technology described in the present disclosure.)
PCT/GB2018/052415 describes a chassis for an electric vehicle, which is perhaps better considered an ‘underbody’ of the vehicle. The underbody described in PCT/GB2018/052415, which is shown at 100 in
This approach makes good use of the characteristics of the electric power train. By accommodating the powertrain within a long, flat underbody that runs the length of the vehicle, there are several packaging, performance and manufacturing benefits. These are set out in PCT/GB2018/052415.
A problem remains, however, of how to provide a body for a vehicle of which an underbody such as that described in PCT/GB2018/052415 forms part. In particular, how should such a body be optimised to make best use of the potential of an electric powertrain? How should it be optimised to work with an underbody such as that described above? How should the two go together?
The General Motors AUTOnomy project from 2002 provides some useful insights: this was a hydrogen fuel cell powered autonomous car concept that proposed a ‘skateboard’ platform—i.e. flat-topped platform that housed the fuel-cell system and electric traction motors under a flat surface that ran the entire length of the vehicle. Set into the surface of this platform were four cylinders, placed approximately at the four corners of where the passenger compact cent would be, but some distance in from the edge or side of the skateboard platform; the idea was that different body types would all share a base with four pins that would each engage and lock into, as well as dis-engage and unlock from, one of these cylinders, docking and securing the body to the skateboard platform and also enabling the entire body to be lifted off the skateboard platform and replaced with a different body. The body would typically be a conventional pressed steel panel body, but with a lower flat surface that would rest on the skateboard platform; because the car designer was not restricted by the presence of an internal combustion engine, or the normal mechanical or electro-mechanical control linkages, some very futuristic body shapes were envisaged, such as the GM Hy-wire, shown in 2002; furthermore, the body was not permanently attached to the skateboard chassis; it was designed to be rapidly (e.g. 30 minutes) undocked and removed, and a different body lowered onto, docked and locked onto the skateboard platform. The AUTOnomy concept, whilst ahead of its time, nevertheless imposes design constraints: for example, attaching a pressed steel body to the skateboard at 4 pre-set mechanical connection points that could both lock and unlock, allowing the body to be lifted off and replaced with a different body, whilst conceptually elegant, is complex and costly to engineer in practice. Further details of the General
Motors AUTOnomy project can be found in US 2004/0069545.
The invention is an automotive vehicle with a skateboard platform or skateboard chassis and a vehicle body that is attached to the skateboard platform or chassis, in which the sides of the vehicle body are formed using a structural frame, made up of multiple structural sub-frames that give structural integrity to the sides of the vehicle body and to which body panels are attached; and in which each structural sub-frame is directly attached to the skateboard platform or chassis.
One advantage of this approach is that it enables fast and reliable assembly of the structural sub-frames to the skateboard platform or chassis, such as fast and reliable automated assembly.
Further aspects, features and sub-features of the invention are summarised at Appendix 1.
Specific embodiments are described below in the Detailed Description by way of example only and with reference to the accompanying drawings.
This section will describe two implementations of the invention.
In general terms, the approach of the present solution is to provide parts of a vehicle body and parts of a vehicle underbody (an underbody, for example, as described in PCT/GB2018/052415) each with interfacing portions that interface to locate the vehicle body relative to the underbody and to provide the structural support for that body and hence for the vehicle.
In one implementation, we have an underbody chassis, the underbody chassis comprising an upper side and a lower side and containing, between the upper side and a lower side, at least one of a battery and an electric motor of an electric powertrain of the vehicle; and a structural body portion of a vehicle body for fixing directly to the underbody chassis; each of the structural body portion and the underbody chassis comprises a plurality of mounting structures, each mounting structure on the structural body portion arranged to mate with a respective mounting structure on the underbody chassis to form a direct attachment between the structural body portion and the underbody chassis. Direct attachment reduces the component count, for example eliminating the need for a separate connector system that is ancillary to the structural body portion.
By providing these features, it is possible to easily and quickly assemble the structural body portion and hence the vehicle body to the underbody chassis. Also, the underbody chassis is able to provide structural support for the vehicle body. Manufacturing and assembly costs and times are lower than with legacy approaches. The vehicle may comprise the vehicle body, as well as the structural body portion of the vehicle body.
The structural body portion may be arranged to support the body of the vehicle on the underbody chassis. It may also form at least part of the safety cell of the vehicle. The structural body portion may comprise a plurality of structural members. The structural members may form part or all of a frame of the body. The frame may be part or all of the safety cell of the vehicle. The vehicle body may comprise one or more body panels. The or each panel may be formed of composite material. The or each body panel may be fixed to the structural members. The or each panel may be partly structural. The vehicle body may be a monocoque. The monocoque may comprise the structural body portion that is for fixing to the underbody chassis. The structural body portion may be integrally formed with the rest of the monocoque. The monocoque may be a monocoque insofar as this is possible with a separate underbody chassis. The structural members may comprise some or all of the mounting structures of structural body portion. Those mounting structures may be formed in ends of the structural members. Those ends of the structural members may be formed as castings, the mounting structures being at least partly formed by that casting (with or without subsequent machining) Other parts of the mounting structures, or other mounting structures, may be formed by extrusions.
The mounting structures on the structural body portion and on the underbody chassis are located to locate the structural body portion (and thereby the vehicle body) relative to the underbody chassis when the respective structures mate. The mounting structures on the structural body portion and on the underbody chassis are profiled to provide structural support of the structural body portion and thereby the vehicle body) relative to the underbody chassis when the respective structures mate and when the structural body portion is fixed to the underbody chassis. The mounting structures on the structural body portion and the mounting structures on the underbody chassis may be profiled such that the mating mounting structures have substantially matching profiles to facilitate direct attachment. One of each mating pair of the mounting structures may have a male portion that is received in a female portion of the other of the mating pair. The male portion may be tapered from its base to its end to help with location during assembly. The female portion may be correspondingly tapered.
The vehicle (or a sub-assembly of a vehicle) may comprise fixing means to fix the structural body portion to the underbody chassis. The direct attachment fixing means may be mechanical and/or chemical fixing means. The direct attachment fixing means may be, for example, a fastener. The direct attachment fixing means may be, for example, an adhesive. The fixing means may be applied at the interface between each mating pair of mounting structures.
The underbody chassis may be a chassis substantially as described in PCT/GB2018/052415. The upper side of the underbody may be—or may substantially correspond to—an internal floor of the vehicle. The underbody chassis may contain the or each battery, and/or power electronics and/or control electronics and/or the or each motor of the electric powertrain of the vehicle. The underbody chassis may contain substantially all the components of the electric powertrain of the vehicle. The upper side of the underbody chassis may extend substantially between the front and the back of the vehicle and between its sides. The upper side may extend substantially to the front and the back of the vehicle and to each side. The upper side may be substantially flat. The upper side may extend between wheel arches of the vehicle. The upper side may extend between and around wheel arches of the vehicle. The upper side may not extend substantially to the front of the vehicle. The upper side may extend towards the front of the vehicle but be spaced therefrom.
The underbody chassis may comprise a plurality of modules, each module being a section of the underbody chassis. The sections may be longitudinal and/or transverse sections. The sections may fit together to form the underbody chassis. One or more of the sections may be substantially the same, for example as a result of being sections of the same extrusion or formed as castings from the same mould.
The mounting structures of the underbody chassis may be formed in structure of the underbody chassis or fixed thereto. The mounting structures of the underbody chassis may be formed in structure of the underbody chassis by casting. The mounting structures of the underbody chassis may be formed as castings in the cast sections of the underbody chassis.
The electric vehicle may be a commercial electric vehicle. It may be a vehicle for transporting cargo. It may be a vehicle for transporting people. It may be a bus. It may be a van. It may be a delivery van. It may be another type of commercial vehicle. It is envisaged that the electric vehicle is a wholly electric vehicle, that is, without an internal combustion engine either as a prime-mover or as a range-extender to be used to power a generator to generate electricity for charging batteries or powering a traction electric motor.
The underbody chassis 10—which from here will be called simply the ‘underbody’— has as upper side 12 and a lower side (not visible, but indicated at 14). There is a cavity between the two sides. Components of the electric powertrain (not visible) of the van are housed in the cavity between the upper side 12 and the lower side 14. These components include the batteries, power electronics, control electronics for controlling the batteries and the power electronics, and electric drive motors.
As can be seen, the underbody 10 forms a low-profile base for the vehicle aligned generally in the plane of the axes of the vehicle's wheels. It looks a bit like a skateboard, but with a thicker ‘board’ to accommodate the electric powertrain. This has several packaging, manufacturing and performance benefits for the vehicle. In terms of packaging, it gives rise to a long, low, flat floor of the van. This allows good use to be made of the internal space of the van and makes it easier to load and unload cargo. Manufacturing and assembly is also improved and will be seen below. Finally, housing heavy powertrain components low down in the underbody 10 improves vehicle dynamics.
The underbody 10 is similar to the arrangement described in PCT/GB2018/052415. Indeed, aspects of that disclosure may be helpful to the skilled reader in understanding the present disclosure and in putting embodiments described herein into effect. As will be seen, the present underbody 10 does however differ from that described in PCT/GB2018/052415.
The underbody 10 is made up of a plurality of sections. Some of these sections are cast aluminium. Some of these sections are aluminium extrusions. Some of the cast sections are substantially the same as each other, having been cast in the same mould, or in moulds designed to be substantially the same. The sections fit together to form the underbody 10. The sections are fixed together by adhesive and by mechanical fixings. Thus, the underbody 10 is modular. The mechanical fixings can be, for example, threaded fasteners engaged with corresponding holes or inserts. The holes or inserts can include a complementary thread for engaging the threaded fasteners, or the threaded fasteners can be configured to form complementary threads in a hole or insert during assembly.
The structural members 100 of the body of the van that are also shown in
Each u-shaped member 120 is formed of several sections. These will be now described with reference to
Returning to
Together, as will be seen, the top surface 130, the side surface 132, the radius 134, the conical locating pin 136 and surrounding surfaces of the foot section 122, all form male mounting structure 139 for mounting the structural members 100 and hence the vehicle body to the underbody 10. The interfacing surfaces of the foot section 122 (and other interfacing regions) can be machined after casting, for example, to increase accuracy of critical dimensions for mating parts.
Corresponding mounting structure of the underbody 10 will now be described with reference to
In assembly of the vehicle, and with reference to
The bolts 138, which in this embodiment are self-tapping bolts, are then fixed into place through the holes in the foot sections 122 into the corresponding holes 148, fixing the combined assembly.
The corresponding and cooperating profiles of the male mounting structure 139 and the female mounting structure 149 result in good location of the structural members 100 relative to the underbody 10 and in providing a high degree of structural support to the combined structure.
In other embodiments it is envisaged that an adhesive, such as glue, may be used to fit the foot sections 122 to the underbody 10.
It is also envisaged that various types of body panel may be used with the structural members 100 described above to form the vehicle body. These may be panels formed of composite material. It is also envisaged that the structural members 100, or their functional equivalents, may be incorporated into a monocoque or part-monocoque body, that body providing the foot sections 122 or the male mounting structure 139 thereof to mate with the female mounting structure 149 of the underbody 10.
In the following section, we will walk-through a simplified variant.
We start with
Each structural sub-frame 120 is made up of a top section or roof bow 124; left and right side straight pillar sections 126 and a foot 122 at the base of each straight pillar sections 126. Each foot 122 rest directly on, and is attached directly to, the skateboard platform 10 and is a single metal casting. In this implementation, there is no specific male and female mounting structures; instead, the underside of the foot 122 forms an open joint and can placed at any suitable position on the top and side of the skateboard platform 10.
The three structural sub-frames 120 are connected together by straight, horizontal bars 110 that give the overall frame (made up of the three u-shaped structural sub-frames 120 and these straight, horizontal bars 110) greater structural integrity.
This mounting position gives both a high degree of structural integrity, and is also fast and reliable to manufacture: access to the mounting position is very good, since it is on the outside edge of the skateboard platform. An extruded aluminium structural beam defines each outer edge of the skateboard platform and the cast feet 122 are attached directly into this structural beam using adhesive, applied to the open joint defined by the ‘L’ shaped lower surface of the foot 122 and the skateboard platform; mechanical fixings, such as flow-drill screws, are also used; these are passed through holes (122) in the cast foot 122 and are then directly drilled into the extruded aluminium structural beam that defines the outer edge of the skateboard platform 10 to give a permanent fixing.
By using the approaches disclosed in this document, better use can be made of the characteristics of an electric power train. In particular, by using the present approaches, the manufacturing and assembly of an electric vehicle can be easier, simpler and less expensive, and a commercial electric vehicle with better packaging and hence better performance as a commercial vehicle can also be provided. This is the case when compared with vehicles based on approaches carried over from and optimised for ICE powertrains.
Appendix 1: Key Features
This Appendix 1 summarises a number of key features. described in this specification. In the following sections, note that any ‘Feature A’-‘Feature F’ can be combined with any other compatible Feature and also any compatible ‘Optional Sub-Feature’ or set of compatible ‘Optional Sub-Features’. And any ‘Optional Sub-Feature’, or set of ‘Optional Sub-Features’ can be combined with any compatible ‘Optional Sub-Feature’ or set of compatible ‘Optional Sub-Features’.
Feature A: An automotive vehicle with a skateboard platform or skateboard chassis and a vehicle body that is attached to the skateboard platform or chassis, in which the sides of the vehicle body are formed using a structural frame, made up of multiple structural sub-frames that give structural integrity to the sides of the vehicle body and to which body panels are attached; and in which each structural sub-frame is directly attached to the skateboard platform or chassis.
Optional Sub-Features
The frame
The ‘U’ shaped, structural sub-frames
The legs
The foot
The vehicle body
The body panels
The skateboard platform or chassis
The vehicle
Feature B: An electric vehicle with a skateboard platform or chassis and a body, in which the sides of the vehicle body are formed using a structural frame to which body panels for the body are attached; and in which the structural frame is directly attached to the skateboard platform or chassis.
Optional Sub-Features
Feature C: A method of assembling a vehicle with a skateboard platform or chassis and a body, in which the sides of the body are formed using a structural frame made up of multiple structural sub-frames to which body panels are attached; comprising the steps of:
(i) assembling one or more structural sub-frames;
(ii) positioning each structural sub-frame on the skateboard platform or chassis and attaching each directly to the skateboard platform or chassis;
(iii) attaching the panels to the structural sub-frames.
Feature D: A vehicle with: an underbody chassis, the underbody chassis comprising an upper side and a lower side and containing, between the upper side and a lower side, at least one of a battery and an electric motor of an electric powertrain of the vehicle; and
Optional Sub-Features
Feature E: Components for an electric vehicle, the components comprising: an underbody chassis, the underbody chassis comprising an upper side and a lower side and arranged to contain, between the upper side and a lower side, at least one of a battery and an electric motor of an electric powertrain of the vehicle; and
Feature F: A method of assembling an electric vehicle or sub-assembly for an electric vehicle as defined in any aspect above. According to the fifth aspect, the method may be a method for assembling a structural body portion and an underbody chassis for an electric vehicle, the method comprising:
| Number | Date | Country | Kind |
|---|---|---|---|
| 19210147.5 | Nov 2019 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/GB2020/052943 | 11/18/2020 | WO |
