Fluid reservoir

Abstract

A fluid reservoir 40, suitable for a vehicle’s electric drive unit (20, Fig. 1), with a housing 42 that defines a chamber 44 for receiving fluid, such as a coolant, and forms a fluid pipe 46. The hous

Description

TECHNICAL FIELD The present disclosure relates to a fluid reservoir. Aspects of the invention relate to a fluid reservoir for a vehicle electric drive unit, to an assembly, to a vehicle drive assembly, to a vehicle, and to a method of fabricating a fluid pipe within the housing of a fluid reservoir. BACKGROUND It is known to provide coolant fluid to a vehicle electric drive unit (EDU) to cool the EDU during use to help prevent overheating. Commonly oil is pumped through channels in the EDU by a pump. The pump picks up the oil (or other suitable fluid) from a reservoir - commonly referred to as a sump - and directs it into cooling channels within the EDU. After the fluid has passed through the channels in the EDU it is cooled and returned to the reservoir. The fluid reservoir and the pump are typically attached to a housing of the EDU. Pipes are provided for transferring the fluid from the reservoir to the pump, and then from the pump to the EDU cooling channels. However, the use of such pipes increase the part count of the system, increases the packaging space requirements, and each end of each pipe must be fluidly sealed. 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 fluid reservoir for a vehicle electric drive unit, to an assembly, to a vehicle drive assembly, to a vehicle, and to a method of fabricating a fluid pipe within the housing of a fluid reservoir as claimed in the appended claims. According to an aspect of the present invention there is provided a fluid reservoir comprising a housing which defines a chamber for receiving fluid, wherein the housing defines a first fluid pipe such that the first fluid pipe is formed by the housing. The fluid reservoir of the invention may be suitable for a vehicle electric drive unit. The fluid reservoir of the invention is advantageous as the first fluid pipe is formed within and by the housing of the fluid reservoir thereby reducing part count, and saving on packaging space and seals that would otherwise be required if separate pipes were used. Optionally the housing may comprise an assembly of component parts, wherein a first component part of the housing defines a first portion of an inner surface of the first fluid pipe, and a second component part of the housing defines a second portion of the inner surface of the first fluid pipe, wherein the first component part is attached to the second component part to define the first fluid pipe. This construction is beneficial as it facilitates manufacture of the reservoir. The housing may optionally define a second fluid pipe such that the second fluid pipe is formed by the housing, wherein a first component part of the housing ora third component part of the housing defines a first portion of an inner surface of the second fluid pipe, and a fourth component part of the housing defines a second portion of the inner surface of the second fluid pipe, wherein the first or third component part is attached to the fourth component part to define the second fluid pipe. The provision od a second fluid pipe is beneficial as it further removes the need for separate pipes. The first component part of the housing may define the first portion of the inner surface of the second fluid pipe so that the first portion of the inner surfaces of both the first and second fluid pipes are formed in the same component part. In one example, the first portion of the inner surface of the first fluid pipe is located on a first side of the first component part of the housing, and the first portion of the inner surface of the second fluid pipe is located on a second side of the first component part of the housing. This configuration may facilitate manufacture or better suit packaging requirements. Optionally the second or fourth component parts of the housing may comprise a cover configured to enclose the first portion of the inner surface of the first fluid pipe and shaped to mirror a flow path of the first fluid pipe. The provision of covers to compete the pipes is beneficial to reduce part size and the length of the connection between the parts. The component parts may optionally comprise plastic components that are welded together. The component parts of the housing may comprise injection moulded parts. In one example, the housing may comprise a first fluid pump attachment and a second fluid pump attachment, wherein a first end of the first fluid pipe is in fluid communication with the first fluid pump attachment, and a first end of the second fluid pipe is in fluid communication with the second fluid pump attachment. The provision of fluid pump attachments integrally formed with the housing further reduces the part count. Optionally, the reservoir comprises: a high pressure fluid outlet; and a low pressure reservoir fluid inlet, wherein a second end of the first fluid pipe is in fluid communication with the high pressure fluid outlet, and a second end of the second fluid pipe is in fluid communication with the low pressure reservoir fluid inlet. As above, the provision of outlets and inlets which are integrally formed with the housing reduces part count. According to an aspect of the present invention there is provided an assembly comprising the reservoir described above, and a fluid pump comprising a high pressure outlet and a low pressure inlet, wherein the high pressure outlet is in fluid communication with the first end of the first fluid pipe, and the low pressure inlet is in fluid communication with the first end of the second fluid pipe. According to a further aspect of the present invention there is provided a vehicle drive assembly comprising the assembly described above and an electric drive unit, wherein the fluid pump and the reservoir are attached to a housing of the electric drive unit. According to a still further aspect of the present invention there is provided a vehicle comprising the reservoir described above, the assembly described above, or the vehicle drive assembly described above. According to yet another aspect of the present invention there is provided a method of fabricating a fluid pipe within the housing of a fluid reservoir, the method comprising: providing a first component part which defines a first portion of an inner surface of an fluid pipe; providing a second component part which defines a second portion of the inner surface of the fluid pipe; and assembling the first component part together with the second component part to form the fluid pipe. 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 anyway 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 fluid reservoir and fluid pump attached to the housing of an EDU; Figure 2 shows a perspective view of the upper side of the fluid reservoir; Figure 3 shows a sectional view of the fluid reservoir; Figure 4 shows an alternative sectional view of the fluid reservoir; Figure 5A shows a plan view of a cover configured to form part of a fluid pipe; Figure 5B shows a perspective view of the other side of the cover shown in Figure 5A; Figure 6A shows a plan view of a second cover configured to form part of a fluid pipe; Figure 6B shows a perspective view of the other side of the cover shown in Figure 6A; Figure 7A shows a plan view of the underside of an upper portion of the fluid reservoir without the cover of Figures 5A and 5B in place; Figure 7B shows a plan view of the underside ofthe upper portion of the fluid reservoirwith the cover of Figures 5A and 5B in place; Figure 7C shows a plan view of the outer side of the upper portion of the fluid reservoir without the cover of Figures 6A and 6B in place; Figure 8 shows a flow chart indicative of a method for fabricating a fluid pipe within the housing of a fluid reservoir; and Figure 9 shows a vehicle in accordance with an embodiment of the invention. DETAILED DESCRIPTION For the purposes of the following description, references to inner, outer, upper and lower etc. are used byway of reference to the orientation in the accompanying figures and are not intended to be limiting. Figure 1 shows a vehicle EDU assembly 10 comprising an EDU 20, a fluid pump 30 and a fluid reservoir 40. The fluid pump 30 and the fluid reservoir 40 are attached to the housing 22 of the EDU 20, and the fluid pump 30 is in operative fluid communication with both the fluid reservoir 40 (as will be described below) and the cooling channels of the EDU. A high pressure fluid outlet 53 formed by the housing 42 of the reservoir 40 fluidly communicates with an inlet 24 formed in the housing 22 of the EDU 20. Figure 2 shows a perspective view of the fluid reservoir 40. The fluid reservoir 40 comprises housing 42 which defines a chamber 44 (see Figures 3 and 4) for receiving and storing a fluid. The housing 42 comprises an upper housing portion 41 and a lower housing portion 43 which are attached together to define the chamber 44. In this example, the upper and lower housing portions 41, 43 comprise injection moulded components which are attached together at their peripheries by laser welding. The housing 42 defines a first, high pressure, fluid pipe 46, and a second, low pressure, fluid pipe 48 such that the first and second fluid pipes 46, 48 are formed by the housing 42. The housing 42 also defines a first pump attachment 45 and a second pump attachment 47. A first end 49 of the first fluid pipe 46 is in fluid communication with the first pump attachment 45, and a first end 51 of the second fluid pipe 48 is in fluid communication with the second pump attachment 47. A second end 52 of the first fluid pipe 46 is in fluid communication with the high pressure fluid outlet 53. The housing 42 also defines a fluid return pipe 64 which is in fluid communication with a fluid outlet of the housing (not shown). Referring now to Figures 3 and 7A, the upper portion 41 of the housing 42 defines a first portion 54 of an inner surface of the first fluid pipe 46, and a cover 56 defines a second portion 55 of the inner surface of the first fluid pipe 46. The cover 56 is configured to enclose the first portion 54 of the inner surface of the first fluid pipe 46 to form an enclosed pipe which is isolated from the fluid chamber 44. The first and second portions 54, 55 of the inner surface of the first fluid pipe 46 are shaped to form a circular cross-section pipe. However, this is not essential and the first fluid pipe 46 may have any suitable cross-section. The cover 56 comprises an injection moulded component which is attached to the underside of the upper portion 41 of the housing 42 by laser welding. As best shown in Figures 5A and 5E3, the cover 56 is shaped to mirror the flow path of the first fluid pipe 46. Figure 5A shows a plan view of the cover 56, and Figure 5B shows a perspective view of the other side of the cover 56 to that shown in Figure 5A. As shown in Figure 7B, when the cover 56 is attached to the first portion 41 of the housing 42, the first portion 54 and the second portion 55 of the inner surface together form the first fluid pipe 46. Referring now to Figures 3, 4 and 7C, the upper portion 41 of the housing 42 also defines a first portion 58 of an inner surface of the second fluid pipe 48, and another cover 60 defines a second portion 59 of the inner surface of the second fluid pipe 48. The cover 60 is configured to enclose the first portion 58 of the inner surface to form the second fluid pipe 48. The first and second portions 58, 59 of the inner surface of the second fluid pipe 48 are shaped to form a circular cross-section pipe. However, this is not essential and the second fluid pipe 48 may have any suitable cross-section. As best shown in Figure 4, a second end 62 of the second fluid pipe 48 is in fluid communication with a fluid pick up 63 so that the second fluid pipe 48 is in fluid communication with the chamber 44. The cover 60 comprises an injection moulded component which is attached to the outer side of the upper portion 41 of the housing 42 by laser welding. As best shown in Figures 6A and 6B, the cover 60 is shaped to mirror the flow path of the second fluid pipe 48. Figure 6A shows a plan view of the cover 60, and Figure 6B shows a perspective view of the other side of the cover 60 to that shown in Figure 6A. When the cover 60 is attached to the first portion 41 of the housing 42 (see Figure 2), the first portion 58 and the second portion 59 of the inner surface together form the second fluid pipe 48. The housing 42 comprises an assembly of four component parts, namely the upper and lower portions 41,43, and the covers 56, 60. The upper portion 41 comprises a first component part of the housing 42, the cover 56 comprises a second component part of the housing 42, lower portion 43 comprises a third component part of the housing 42, and the other cover 60 comprises a fourth component part of the housing 42. In use, the low pressure inlet of the pump 30 is attached to the second pump attachment 47 which forms a low pressure reservoir fluid outlet, and the high pressure outlet of the pump 30 is attached to the first pump attachment 45 which forms a high pressure fluid inlet to the first pipe 46. When the pump 30 is operated, fluid is drawn into the pump 30 from the chamber 44 via the fluid pick up 63 and the second fluid pipe 48. Pressurised fluid is then directed into the EDU cooling channels via the first fluid pipe 46, the high pressure fluid outlet 53 and the inlet 24. Once the fluid has passed through the cooling channels within the EDU, it is returned to the chamber 44 via the fluid return pipe 64. Figure 8 shows a flow chart indicative of a method 90 for fabricating a fluid pipe 46 within the housing 42 of a fluid reservoir 40. In a first step 91, the method comprises providing a first component part (for example, the upper portion 41 of the housing 42) which defines a first portion 54 of an inner surface of a fluid pipe 46. A second step 92 comprises providing a second component part (for example, the cover 56) which defines a second portion 55 of the inner surface of the fluid pipe 46. In a third step 93, the method 90 comprises assembling the first component part 41 together with the second component part 56 to form the fluid pipe 46. The method 90 may be used to fabricate any number of fluid pipes within the housing 42. In one example the first and second component parts comprise plastic which may be shaped in an injection moulding process. In one example, the first and second component parts are laser welded together when assembling the first component part together with the second component part to form the fluid pipe. A vehicle 100 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figure 7. As shown in Figure 7, the assembly comprising the EDU, the fluid pump and the reservoir in installed in the vehicle 100. 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. In particular, the first portions 54, 58 of the inner surfaces of the first and second fluid pipes 46, 48 respectively may each be formed on the same side of the upper portion 41 of the housing 42 rather than on opposite sides as described above. It is not essential that the first fluid pipe 46 be formed with its first inner surface portion 54 located on the underside of the first portion 41 of the housing 42. Similarly, it is not essential that the second fluid pipe 48 be formed with its first inner surface portion 58 located on the upper side of the first portion 41 of the housing 42. Still further, the first portions 54, 58 of the inner surfaces of the first and second fluid pipes 46, 48 may be formed on the inner or outer side of the lower portion 43 of the housing 42, or on opposite sides of the of the lower portion 43 of the housing 42. One fluid pipe may be at least partially formed by the upper portion 41 of the housing 42, and another fluid pipe may be at least partially formed in the lower portion 43 of the housing 42. It is not essential that two fluid pipes be formed by the housing 42, and the housing 42 may only form one fluid pipe.

Claims

1. A fluid reservoir for a vehicle electric drive unit, the fluid reservoir comprising a housing which defines a chamber for receiving fluid, wherein the housing defines a first fluid pipe such that the first fluid pipe is formed by the housing.

2. The reservoir of claim 1, wherein the housing comprises an assembly of component parts, wherein a first component part of the housing defines a first portion of an inner surface of the first fluid pipe, and a second component part of the housing defines a second portion of the inner surface of the first fluid pipe, wherein the first component part is attached to the second component part to define the first fluid pipe.

3. The reservoir of claim 2, wherein the housing defines a second fluid pipe such that the second fluid pipe is formed by the housing, wherein a first component part of the housing or a third component part of the housing defines a first portion of an inner surface of the second fluid pipe, and a fourth component part of the housing defines a second portion of the inner surface of the second fluid pipe, wherein the first or third component part is attached to the fourth component part to define the second fluid pipe.

4. The reservoir of claim 3, wherein the first component part of the housing defines the first portion of the inner surface of the second fluid pipe.

5. The reservoir of claim 4, wherein the first portion of the inner surface of the first fluid pipe is located on a first side of the first component part of the housing, and the first portion of the inner surface of the second fluid pipe is located on a second side of the first component part of the housing.

6. The reservoir of any one of claims 3 to 5, wherein the second component part of the housing comprises a cover configured to enclose the first portion of the inner surface of the first fluid pipe and shaped to mirror a flow path of the first fluid pipe.

7. The reservoirof any one of claims 3 to 6, wherein the fourth component part of the housing comprises a cover configured to enclose the first portion of the inner surface of the second fluid pipe and shaped to mirror a flow path of the second fluid pipe.

8. The reservoir of any one of claims 3 to 7, comprising plastic component parts that are welded together.

9. The reservoir of any one of claims 3 to 8, wherein the component parts of the housing comprise injection moulded parts.

10. The reservoirof any one of claims 3 to 9, wherein the housing comprises a first fluid pump attachment and a second fluid pump attachment, wherein a first end of the first fluid pipe is in fluid communication with thefirst fluid pump attachment, and a first end of the second fluid pipe is in fluid communication with the second fluid pump attachment.

11. The reservoir of claim 10, comprising:a high pressure fluid outlet; anda low pressure reservoir fluid inlet, wherein a second end of the first fluid pipe is in fluid communication with the high pressure fluid outlet, and a second end of the second fluid pipe is in fluid communication with the low pressure reservoir fluid inlet.

12. An assembly comprising the reservoir of claim 10 or 11, and a fluid pump comprising a high pressure outlet and a low pressure inlet, wherein the high pressure outlet is in fluid communication with the first end of the first fluid pipe, and the low pressure inlet is in fluid communication with the first end of the second fluid pipe.

13. A vehicle drive assembly comprising the assembly of claim 12 and an electric drive unit, wherein the fluid pump and the reservoir are attached to a housing of the electric drive unit.

14. A vehicle comprising the reservoir of any one of claims 1 to 11, the assembly of claim 12 or the vehicle drive assembly of claim 13.15, A method of fabricating a fluid pipe within a housing of a fluid reservoir, the method comprising: providing a first component part which defines a first portion of an inner surface of a fluid pipe; providing a second component part which defines a second portion of the inner surface of the fluid pipe; andassembling the first component part together with the second component part to form the fluid pipe.

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