A rear subframe for a vehicle

Abstract

A rear subframe 10 is provided for supporting an electric machine (102, Figure 2) of a vehicle. Rear subframe 10 has a front cross-member 20 and a rear cross-member 30, connected by lateral members 40

Description

TECHNICAL FIELD The present disclosure relates to a rear subframe for a vehicle. Aspects of the invention relate to a rear subframe for supporting an electric machine of a vehicle, to a sub-assembly for a vehicle, to a vehicle, and to a method of manufacturing a rear subframe for a vehicle. BACKGROUND It is known to provide a rear subframe in a vehicle. The rear subframe can be used to connect various components, such as a suspension assembly to the vehicle. As vehicles have become heavier, for example due to the requirement of supporting heavy battery packs, additional requirements of rear subframes may be needed. For example, with increased weight supported by the subframe, the subframe may require increased stiffness, this can be achieved by utilising more exotic alloy materials, comprising expensive alloying elements or requiring time intensive heat treatments, use of such materials and methods can be cost prohibitive. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a rear subframe for supporting an electric machine of a vehicle, a sub-assembly for a vehicle, a vehicle, and a method of manufacturing a rear subframe for a vehicle as claimed in the appended claims. According to an aspect of the present invention there is provided a rear subframe for supporting an electric machine of a vehicle, the rear subframe comprising: a front cross-member; a rear cross-member; a first lateral member and a second lateral member each connecting the front cross-member to the rear cross-member; an intermediate cross-member connecting the first lateral member to the second lateral member; wherein the intermediate cross-member is located closer to one of the front cross-member or the rear cross-member than the other of the front cross-member or the rear crossmember; and wherein at least one of the cross-members and / or lateral members comprises a frame mounting portion for connecting the subframe to a vehicle structure. The rear subframe for the vehicle advantageously has an intermediate cross-member which provides additional stiffness to the rear subframe. Such an intermediate cross-member is particularly advantageous when used in a Battery Electric Vehicle (‘BEV’). BEVs have electric machines which have a greater volume than internal combustion engines (‘ICE’) and differentials used with ICEs. As a result, the first (front) and second (rear) cross-members may need to be placed further away from each other to provide a large enough envelope to fit the electric machine and / or associated components of the BEV. Increasing the envelope volume of the subframe can affect the stiffness of the subframe itself as the first and second crossmembers are disposed at a greater distance from each other. The inventors of the present invention have advantageously found that the provision of an intermediate cross-member provides increased stiffness, which, compensates for the increased envelope volume. According to an additional aspect of the present invention there is provided a subframe for a vehicle, the subframe comprising: a front cross-member; a rear cross-member; a first lateral member and a second lateral member each connecting the front cross-member to the rear cross-member; an intermediate cross-member connecting the first lateral member to the second lateral member; wherein the intermediate cross-member is located closer to one of the front cross-member or the rear cross-member than the other of the front cross-member or the rear crossmember; and wherein at least one of the cross-members and / or lateral members comprises a frame mounting portion for connecting the subframe to a vehicle structure. The subframe may be a front subframe or a rear subframe. The subframe of the additional aspect has the advantages of the prior aspect. The following optional features may be utilised with either or both the subframe aspects described above. Optionally, at least one of the first and second cross-members may be disposed at a first height on the rear subframe, and the intermediate cross-member being positioned at a second height on the rear subframe. By providing the intermediate cross-member at a different height to the front and / or rear cross-member the rear subframe volume defined by the subframe is greater than if the intermediate cross-member were at the same height as the other cross-members. Optionally, the rear subframe may comprise at least one suspension mounting point disposed on one of the: front cross-member, rear cross-member, first lateral member and second lateral member; and wherein an end of the intermediate cross-member is connected one of the first lateral member or second lateral member by a region adjacent the at least one suspension mounting point. The suspension mounting point being located adjacent to the first or second lateral member may provide additional stiffness in the region of the suspension mounting point. Optionally, the subframe may comprise a second suspension mounting point disposed on one of the: front cross-member, rear cross-member, first lateral member and second lateral member; and wherein a second end of the intermediate cross-member is connected to one of the first lateral member or second lateral member by a region adjacent the at least one suspension mounting point. The second suspension mounting point, being located adjacent to the first or second lateral member, may provide additional stiffness in the region of the suspension mounting point. Optionally, the intermediate cross-member may comprise at least one fixing point configured to connect to a vehicle component. The intermediate cross-member can be used to connect additional components of the vehicle and fix them to the rear subframe. For example, the vehicle component may be an undertray, ducting for wiring, or other fixtures or fittings. Optionally, the intermediate cross-member may be connected to the first lateral member at a first location and connected to the second lateral member at a second location opposite the first location. By connecting the intermediate cross-member to the first and second lateral members the rear subframe can be quickly and efficiently manufactured. Optionally, the intermediate cross-member may be welded to the first lateral member at the first location and welded to the second lateral member at the second location. By welding the intermediate cross-member to the first and second lateral members the subframe can be quickly and efficiently manufactured, for example by robotic welding systems. Optionally, the intermediate cross-member may be an at least a partially hollow member. Provision of an at least partially hollow member, for example a tubular member or tube, provides weight saving over a solid component. This weight saving means that the vehicle comprising the rear subframe may be more fuel efficient in use. The hollow member may be completely hollow (like a pipe). The hollow member may be an extruded member. The hollow member may have a constant cross-section along its length. The constant cross-section may be circular, annular, oval, rectangular, square, etc. Optionally, the front cross-member may comprise a front casting and the rear cross-member comprises a rear first casting and a rear second casting; and wherein the rear first casting and rear second casting are connected. By providing the rear subframe as separate castings that are then connected to produce the final component there is a reduction in the likelihood of casting defects, such as solidification shrinkage, which can affect larger castings. Optionally, the rear first casting and rear second casting may be connected by an at least partially hollow member forming at least a portion of the second cross-member. The hollow member may be completely hollow (like a pipe). The hollow member may be an extruded member. The hollow member may have a constant cross-section along its length. By providing a hollow extruded member to connect the first and second rear castings a weight saving can be achieved as compared to utilising a single large casting and / or providing a similar extension between the two rear castings that is solid. The hollow extruded member may be welded to the rear first casting and welded to the rear second casting. The connection may be a welded connection or may be achieved by various fixtures and / or fittings to connect the rear first and second castings to the at least partially hollow member. Optionally, the rear subframe may further comprise one or more mounting bosses for connecting the rear subframe to a vehicle structure; and wherein the one or more mounting bosses are located on one or both of the front cross-member and the rear cross-member. By providing mounting bosses on the front and / or rear cross-members the subframe may be more easily mounted to a vehicle structure, such as a frame, or other chassis component. There may be four mounting bosses. Each of the four mounting bosses may be located at a corner or extremity of the subframe, wherein two of the mounting bosses are located on the front cross-member and two of the mounting bosses are located on the rear cross-member. In an additional aspect of the invention, there is provided a sub-assembly for a vehicle, the sub-assembly comprising a rear-subframe and an electric machine, and a suspension assembly; the suspension assembly is connected to the rear subframe; the electric machine being at least partially received by the rear subframe in a volume (V) defined by the first, second and intermediate cross-members and lateral members of the rear subframe. The sub-assembly of the invention enables an electric machine to be disposed at a lower centre-of-gravity than other sub-assemblies which do not have an intermediate cross-member. Such an arrangement may increase the stability of the vehicle by lowering the centre-of-gravity of heavy components such as the electric machine. According to another aspect of the invention, there is provided a vehicle comprising the rear subframe or the sub-assembly. Optionally, wherein the rear subframe may be disposed in a rear portion (R) of the vehicle, and wherein the first cross-member is orientated in the vehicle to face the forward end (F) of the vehicle and the second cross-member is orientated in the vehicle to face the rearward end (R) of the vehicle. The forward end of the vehicle is the end of the vehicle which has the bonnet (also known as a hood). Forward is the direction in which the vehicle is intended to move in when the vehicle is in a forward drive mode. The rearward end of the vehicle is the end of the vehicle which has the boot (also known as a trunk). Rearward is the direction in which the vehicle is intended to move in when the vehicle is in a reverse drive mode. According to a further aspect of the invention, there is provided a method of manufacturing a rear subframe fora vehicle, the method comprising the steps of providing: a front cross-member; a rear cross-member; a first lateral member; a second lateral member; an intermediate cross-member; and wherein at least one of the cross-members and / or lateral members comprises a frame mounting portion for connecting the subframe to a vehicle structure; the method further comprising the steps of: connecting the first cross-member to the second cross-member by the first lateral member, connecting the first cross-member to the second cross-member by the second lateral member; connecting the intermediate cross-member to the first lateral member and the second lateral member; and wherein the intermediate cross-member is located closer to one of the front cross-member or the rear cross-member than the other of the front cross-member or the rear cross-member. The method provides a simple method of manufacturing a subframe of a vehicle which may be manufactured by hand or as part of an automated process line for example with the aid of robotic arms. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle in accordance with an embodiment of the invention; Figure 2 shows a schematic example of a subsystem of the vehicle in Figure 1; Figure 3 shows an isometric view of a rear subframe in accordance of an embodiment of the invention; Figure 4 shows a bottom-up view of the rear subframe of Figure 3; Figure 5 shows a schematic side-on view of the rear subframe in accordance with an embodiment of the invention; and Figure 6 shows a flowchart with method steps in accordance with an embodiment of the invention. DETAILED DESCRIPTION A rear subframe 10 is accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 6. The rear subframe 10 is suitable for supporting an electric machine 102 (or prime mover 102) of a vehicle 1. As shown in Figure 2 the rear subframe 10 is part of a subassembly 100 of the vehicle 1. The rear subframe 10 according to the invention advantageously provides additional stiffness by virtue of an intermediate cross-member 32. The intermediate cross-member is particularly advantageous for rear subframes used with electric machines 102 that have large volumes and / or ‘complex’ shaped bodies which otherwise would need to be disposed higher in prior subframes to enable similar stiffness levels as the present invention. When disposed higher on the subframe, this may affect the centre of gravity of the vehicle, as the heavy component (the electric machine 102) may be disposed at a higher elevation. Offsetting the higher centre of gravity may necessitate additional components in prior systems and / or repackaging other components. As shown in Figure 1, the vehicle 1 is a wheeled passenger vehicle. The passenger vehicle 1 depicted is of the 4x4 or SUV type, however the vehicle 1 may be a car, a van, a light goods vehicle, or other such vehicle. The vehicle 1 has a front, F as shown in Figure 1 and 2. The front F is in the direction that the vehicle 1 will move in a forward drive mode. The rear R is disposed on the opposite end of the vehicle 1 and is the direction that the vehicle 1 will move in in a reverse drive mode. The vehicle has front wheels 2a, 2b and rear wheels 4a, 4b. Rear wheel 4a is not visible in the view of the vehicle in Figure 1 as it is obscured by the vehicle 1 body. The vehicle 1 has a powertrain. The powertrain comprises a propulsion system comprising the at least one prime mover 102. The prime mover 102 is an electric traction motor or alternatively the vehicle 1 may comprise a plurality of prime movers 102. Where a plurality of prime movers 102 are provided they may be a plurality of electric traction motors. Where the at least one prime mover 102 comprises an electric traction motor this is an electric motor arranged to convert electrical energy into kinetic energy in the form of mechanical torque and may also be arranged to convert kinetic energy into electrical energy. The electric traction motor 102 may be an alternating current induction motor or a permanent magnet motor, or another type of suitable electric machine. The electric traction motor 102 is a traction motor configured to enable at least an electric mode of operation, comprising electric-only driving. That is, the electric traction motor 102 can drive the vehicle 1 by itself (without additional torque provided by a second torque source such as an IC engine). Another term for the electric traction motor 26 is an electric drive unit (EDU). In order to store electrical energy for the electric traction motor 102, the vehicle 1 comprises an electrical energy storage means. The electrical energy storage means can be a traction battery. The traction battery provides a nominal voltage required by electrical power users such as the electric traction motor 102. The traction battery may be a high voltage battery. The traction battery may have a voltage and capacity to support electric only driving for sustained distances. The traction battery may have a capacity of several kilowatt-hours, to maximise range. The capacity may be in the tens of kilowatt-hours, or even over a hundred kilowatt-hours. Although the traction battery is described as one entity, the function of the traction battery could be implemented using a plurality of small traction batteries in different locations on the vehicle 1. An inverter may be provided to convert between the DC output of the traction battery and the AC input as may be required for the electric machine 102. The prime mover(s) 102 are selectively operable for the purpose of providing drive torque for accelerating the vehicle 1. In alternative configurations with two prime movers 102, the first prime mover 102 may provide drive to a front axle and the second prime mover 102 provides drive to a rear axle, or vice versa. Figure 2 schematically illustrates an example of at least part of the sub-assembly 100 of the vehicle 1 with rear wheels 4a, 4b, the rear subframe 10, a suspension assembly 108 (comprising a toe link 106 and a wheel carrying arrangement 104), an optional steering component 60 and a prime mover 102. The rear subframe 10 is configured to connect to some or all of these components and optionally other components not shown. In alternative configurations, the steering component 60 may be exchanged for a bracket which configures the rear subframe 10 in a non-rear steered wheel configuration as opposed to a rear-wheel-steer configuration as depicted in Figure 2. The sub-assembly 100 is advantageously configured to work in both configurations. With reference to Figures 2 to 5 the rear subframe 10 will be described in more detail. As shown in Figure 3 the rear subframe comprises a front cross-member 20, a rear cross-member 30, a first lateral member 40 and a second lateral member 50. The front and rear cross-members 20, 30 are connected by the first lateral member 40. The front and rear cross-members 20, 30 are connected by the second lateral member 50. The connection of the lateral members and cross-members 20, 30, 40, 50 forms a rectangular frame onto which components of the vehicle 1, such as the wheels 4a, 4b may be connected and / or mounted as indicated by the schematic drawing of Figure 2. The first lateral member 40 may be made up of an extension of the front cross-member 20 and / or an extension of the rear cross-member 30 such that the first lateral member 40 at least partially comprises a part of the front and / or rear cross-members 20, 30. Or, the first lateral member 40 may be made up entirely of the front and / or rear cross-members 20, 30 as is shown in Figure 3 and 4. In such a case the front and rear cross-members 20, 30 are connected at connection 41 to form the first lateral member 40. The connection 41 may be a welded connection. Alternatively, the first lateral member 40 may be a casting or tubing connected to the front and rear crossmembers 20, 30. The second lateral member 50 may be similarly constructed to the first, with a further connection 51 between the front and rear cross-members 20, 30. The rear subframe 10 additionally comprises an intermediate cross-member 32. The intermediate crossmember 32 provides additional stiffness to the rear subframe. The intermediate cross-member 32 is connected to the first and second lateral members 40, 50 as is shown in Figure 3 by connections 33 and 34. The intermediate cross-member 32 is connected to the first lateral member 40 via connection 33. The intermediate cross-member 32 is connected to the second lateral member 50 via connection 34. The connections 33, 34 are welded connections. Alternatively, the connection may be via fixtures or fittings known in the art. As shown in Figures 3 and 4 the intermediate cross member 32 is connected to the first lateral member 40 at connection 33. Connection 33 is at a first region adjacent to a suspension mounting point 14a. The suspension mounting point 14a is suitable for connection to a part or portion of the suspension assembly 108. As shown in Figures 3 and 4 the intermediate cross member 32 is connected to the second lateral member 50 at connection 34. Connection 34 is at a second region adjacent to a suspension mounting point 14b. The suspension mounting point 14b is suitable for connection to a part or portion of the suspension assembly 108. As shown in Figures 3, 4 and 5 the intermediate cross-member 32 is disposed closer to the rear crossmember 30 than the front cross-member 20. This is indicated by distance d1 which is between the front cross-member 20 and the intermediate cross-member 32 and the distance d2 which is between the rear cross-member 40 and the intermediate cross-member 32. As shown in Figure 5, d1 is greater than d2 indicating that the rear cross-member 30 and intermediate member 32 are closer together than the front cross-member 20 and the intermediate member 32. The first and / or second lateral members 40, 50 each define a longitudinal axis A-A. The longitudinal axis A-A is shown in Figure 5 for the second lateral member 50. As Figure 5 shows a side on view of the rear subframe 10, the first lateral member 40 is hidden from view. Figure 5 shows that the intermediate cross-member 32 and front and / or rear cross-members 20, 30 are disposed at different distances on the rear subframe 10 measured from the longitudinal axis A-A (as shown in Figure 5) of the first and / or second lateral member 40, 50. The distance h2 between the axis A-A and the intermediate member 32 is greater than the distance hi between the axis A-A and the front and / or rear cross-member 20, 30. In use, therefore, the intermediate member 32 is disposed closer to the ground surface on which the vehicle is supported than the front and / or rear cross member The intermediate cross member 32 may therefore provide some protection to the electric machine 102 and / or other associated components from the surface that the vehicle 1 is supported on. The intermediate cross-member 32 is at least a partially hollow member 32, for example a tubular member or tube, providing weight saving over a solid component. This weight saving means that the vehicle comprising the rear subframe may be more energy efficient in use. The member 32 may be completely hollow (like a pipe). Such a hollow member 32 may be an extruded member. The hollow member 32 may have a constant cross-section along its length. The constant cross-section may be circular, annular, oval, rectangular, square, etc. The intermediate cross-member 32 may have fixtures and / or fittings for connecting components to the intermediate cross-member 32. For example, the intermediate cross-member 32 may have a fixture / fitting for connecting an undertray to the rear subframe 10. The front cross-member 20 comprises a front casting. Alternatively, the front cross-member may be machined from a billet of alloy feedstock. The rear cross-member 30 is made up a casting. The casting may comprise a rear first casting 36 and a second rear casting 38 or first and second casting members. The rear first and second castings 36, 38 are connected to form the rear cross-member 30. Optionally, the rear cross-member 30 additionally comprises a member 31. The member 31, shown in Figure 3 and 4, is connected to the rear first casting 36 at a connection point 37 and to the rear second casting 38 at a second connection point 39. In the embodiment shown in Figure 4 the rear first casting 36, rear second casting 38 and the member 31 together comprise the rear cross-member 30. It is however envisioned that the rear cross-member 30 may be a single casting, a two-part casting, or a three-part casting. The member 31 is at least a partially hollow member 31, for example a tubular member or tube, providing weight saving over a solid component. This weight saving means that the vehicle comprising the rear subframe may be more energy efficient in use. The member 31 may be completely hollow (like a pipe). Such a hollow member 31 may be an extruded member. The hollow member 31 may have a constant crosssection along its length. The constant cross-section may be circular, annular, oval, rectangular, square, etc. The cross-members 20, 30, 32, 40, 50 together define an volume V for the receipt of at least a portion of the prime mover 102 where the prime mover 102 is installed in the sub-assembly 100 for a rear-wheel drive or four-wheel drive vehicle 1 as shown in Figure 2. Turning back to Figure 3 and the rear subframe 10, the first and second lateral members each have a recess 42, 52. The first and second recesses 42, 52 are configured to receive a portion of a steering component, wherein when the steering component is mounted to the rear subframe the steering component configures the vehicle in a four-wheel steering configuration. The steering component may be a portion of a rear steering rack that may be mounted to the rear subframe to make the vehicle 1 a four-wheel steer vehicle 1. The first and second recesses 42, 52 are scalloped. The scallops are sized such that in use the portion of the steering component may be constrained within the recess. The steering component may be mounted to the rear subframe via mounting points 44, 46 for the first recess 42 and mounting points 54, 56 for the second recess. The mounting points 44, 46 are located either side of the first recess 42. The mounting points 54, 56 are located either side of the second recess 52. The mounting points 44, 46, 54, 56 may be holes sized for receipt of a bolt or self-tapping fixing. As will be apparent, when the steering component is mounted to the rear subframe 10, the rear subframe 10 is configured in the rear-wheel steer configuration. When the steering component is not mounted to the rear subframe 10, the rear subframe 10 is not in a rear-wheel steer configuration. The rear subframe 10 may optionally have an alignment feature 48. The alignment feature 48 is used to assist with aligning the steering component when a vehicle 1 is being manufactured. The alignment feature 48 is a hole adjacent the mounting point 44 of the first recess 42 as is shown in Figure 3. The hole is sized for receipt of a dowl or another feature which assists with mounting the steering component to the rear subframe 10. Alternatively, the mounting feature may be an extension or rod which is continuous or contiguous with the first lateral member 40. The rear subframe 10 may optionally have a second alignment feature 58. The alignment feature 58 is used to assist with aligning the steering component when a vehicle 1 is being manufactured. The alignment feature 58 is a hole adjacent the mounting point 54 of the first recess 52 as is shown in Figure 3. The hole is sized for receipt of a dowl or other feature which assists with mounting the steering component to the rear subframe 10. Alternatively, the mounting feature may be an extension or rod which is continuous or contiguous with the second lateral member 50. The rear subframe 10 may have one or more bushings 12 (also known as connection points 12 or bosses 12) as shown in Figure 3 and 4. The bushings 12 are used to connect the rear subframe 10 to additional components or other vehicle 1 subframes or other vehicle structures. Figure 8 illustrates a method 200 according to an embodiment of the invention. The method 200 is a method of manufacturing a rear subframe for a vehicle 1, such as for the vehicle 1 illustrated in Figure 1. In particular, the method 200 is a method of providing an intermediate cross-member 32 for a rear subframe 10. The provision of an intermediate cross-member 32 provides additional stiffness to a rear subframe which is particularly advantageous when used with large prime movers 102. The method 200 comprises the step S210 of providing: a front cross-member 20, a rear cross-member 30, a first lateral member 40, a second lateral member 50, an intermediate cross-member 32, and wherein at least one of the cross-members 20, 30, 32, 40, 50 comprises a frame mounting portion 12 for connecting the subframe to a vehicle structure. The method further comprises the step S220 of connecting the front cross-member 20 to the rear crossmember 30 by the first lateral member 40. The connection may be made by welding the components together. The front cross-member 20 and the rear cross-member 30 are connected by the second lateral member 50. The connection may be made by welding the components together. Subsequently, at step S230 the intermediate cross-member 32 is connected to the first lateral member 40 and the second lateral member 50 such that the intermediate cross-member 32 is located closer to one of the front cross-member 20 or the rear cross-member 30 than the other of the front cross-member 20 or the rear cross-member 30. The method may additionally comprise additional features of any of the embodiments described above. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A rear subframe for supporting an electric machine of a vehicle, the rear subframecomprising:a front cross-member;a rear cross-member;a first lateral member and a second lateral member each connecting the front cross-member to the rear cross-member;an intermediate cross-member connecting the first lateral member to the second lateral member;wherein the intermediate cross-member is located closer to one of the front cross-member or the rear cross-member than the other of the front cross-member or the rear crossmember; andwherein at least one of the cross-members and / or lateral members comprises a frame mounting portion for connecting the subframe to a vehicle structure.

2. A rear subframe according to claim 1, wherein at least one of the first and second cross-members are disposed at a first height on the rear subframe, and the intermediate cross-member being positioned at a second height on the rear subframe.

3. A rear subframe according to any preceding claim, further comprising at least one suspension mounting point disposed on one of the:front cross-member, rear cross-member, first lateral member and second lateral member; andwherein an end of the intermediate cross-member is connected to one of the first lateral member or second lateral member by a region adjacent the at least one suspension mounting point.

4. A rear subframe according to any claim 3, further comprising a second suspension mounting point disposed on one of the:front cross-member, rear cross-member, first lateral member and second lateral member; andwherein a second end of the intermediate cross-member is connected one of the first lateral member or second lateral member by a region adjacent the at least one suspension mounting point.

5. A rear subframe according to any preceding claim, wherein the intermediate cross-member comprises at least one fixing point configured to connect to a vehicle component.

6. A rear subframe of any preceding claim, wherein the intermediate cross-member is connected to the first lateral member at a first location and connected to the second lateral member at a second location opposite the first location.

7. A rear subframe of claim 6, wherein the intermediate cross-member is welded to the first lateral member at the first location and welded to the second lateral member at the second location.

8. A rear subframe of any preceding claim, wherein the intermediate cross-member is an at least a partially hollow member.

9. A rear subframe according to any preceding claim, wherein the front cross-member comprises a front casting and the rear cross-member comprises a rear first casting and a rear second casting; and wherein the rear first casting and rear second casting are connected.

10. A rear subframe according to claim 7, wherein the rear first casting and rear second casting are connected by an at least partially hollow member forming at least a portion of the rear cross-member.

11. A rear subframe according to any preceding claim, further comprising one or more mounting bosses for connecting the rear subframe to a vehicle structure; and wherein the one or more mounting bosses are located on one or both of the front cross-member and the rear cross-member.

12. A sub-assembly for a vehicle comprising a rear-subframe according to any preceding claim and an electric machine, and a suspension assembly; whereinthe suspension assembly is connected to the rear subframe;the electric machine being at least partially received by the rear subframe in a volume defined by the first, second and intermediate cross-members and lateral members of the rear subframe.

13. A vehicle comprising the rear subframe according to any of claims 1 to 11 or the sub-assembly according to claim 12.

14. A vehicle according to claim 13, wherein the rear subframe is disposed in a rear portion of the vehicle, and wherein the front cross-member is orientated in the vehicle to face the forward end of the vehicle and the rear cross-member is orientated in the vehicle to face the rearward end of the vehicle.

15. A method of manufacturing a rear subframe for a vehicle, according to any of claims 1 to 11, the method comprising the steps of providing:a front cross-member;a rear cross-member;a first lateral member;a second lateral member;an intermediate cross-member; andwherein at least one of the cross-members and / or lateral members comprises a frame mounting portion for connecting the subframe to a vehicle structure;the method further comprising the steps of:connecting the front cross-member to the rear cross-member by the first lateral member,connecting the front cross-member to the rear cross-member by the second lateral member;connecting the intermediate cross-member to the first lateral member and the second lateral member; andwherein the intermediate cross-member is located closer to one of the front cross-member or5 the rear cross-member than the other of the front cross-member or the rear cross-member.15

Images