GB2609961A

GB2609961A - Coolant manifold for an electric motor

Info

Publication number: GB2609961A
Application number: GB2111882.3A
Authority: GB
Inventors: Abenojar Jesus
Original assignee: Jaguar Land Rover Ltd
Current assignee: Jaguar Land Rover Ltd
Priority date: 2021-08-19
Filing date: 2021-08-19
Publication date: 2023-02-22
Also published as: GB202111882D0

Abstract

A coolant manifold 1 for distributing coolant within an electric motor (3, fig 4) the manifold comprising a locating band 31 having a closed profile for locating the manifold in a circular aperture (17, fig 4) formed in a housing (11, fig 4) of the motor. The band is resiliently deformable and, in an undeformed state, has a first dimension along a major axis a1 which is greater than a second dimension along a minor axis b1, where the major axis is perpendicular to the minor axis. The band is compressible along the major axis for insertion into the aperture. The compression of the band generates a spring force for biasing a radially outer surface 41 of a coolant gallery 33 wall towards the sidewall of the housing when the band is inserted. The manifold may comprise a coolant gallery comprising an inlet aperture (35, fig 3) and outlet apertures 37, the gallery being formed by a wall having a radially outer surface for engaging with a sidewall of the housing. The closed profile of the band may be an ellipse or oval shape in the undeformed state. The band may comprise annular frame members 45-1, 45-2. The manifold may be fibre reinforced polymer. The manifold may be used to cool stator winding connectors of a motor used in a vehicle.

Description

COOLANT MANIFOLD FOR AN ELECTRIC MOTOR

TECHNICAL FIELD

The present disclosure relates to a coolant manifold for an electric motor. Aspects of the invention relate to a coolant manifold, an electric motor comprising a coolant manifold; and a vehicle comprising an electric motor.

BACKGROUND

It is known to circulate a coolant, such as oil, through an electric motor to provide cooling. This cooling process is used in electric motors, for example electric traction motors operative to generate a tractive force to propel a vehicle. The coolant is introduced into a housing of the electric motor to provide cooling of the components within the housing, such as electrical connectors provided on stator windings. The coolant may be introduced at different angles depending on the configuration of the inlet port. This may result in non-uniform cooling of the components of the electric motor.

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 coolant manifold, an electric motor and a vehicle as claimed in the appended claims Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out 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 schematic representation of a vehicle incorporating an electric traction motor having a coolant manifold in accordance with an embodiment of the present invention; Figure 2 shows a schematic representation of a longitudinal section through the electric traction motor shown in Figure 1; Figure 3 shows a detailed view of a portion of the longitudinal section through the electric traction motor shown in Figure 2; Figure 4 shows a partial assembly view along the longitudinal axis showing the coolant manifold installed in the housing of the electric motor shown in Figure 2; Figure 5 shows a perspective view of the coolant manifold in accordance with an embodiment of the present invention; Figure 6 shows an end view of the coolant manifold along the longitudinal axis in accordance with an embodiment of the present invention; Figure 7A shows the coolant manifold in accordance with an embodiment of the present invention in an undeformed state; Figure 7B shows the coolant manifold in accordance with an embodiment of the present invention in a deformed state; Figure 8 shows an enlarged view of an alignment feature of the coolant manifold and housing; and Figure 9 shows a longitudinal section view showing the alignment feature located in a recess formed in the housing.

DETAILED DESCRIPTION

A coolant manifold 1 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures. The coolant manifold 1 is configured to distribute a liquid coolant, such as coolant, within an electric motor 3. The electric motor 3 is a traction motor for generating torque to propel a vehicle 5 shown schematically in Figure 1. It is to be appreciated that whilst the vehicle 5 shown in Figure 1 comprises only one electric motor 3 in other embodiments (not shown) the vehicle 5 may comprise more than one electric motor 3, The electric motor 3 forms part of an electric drive unit (EDU) in the vehicle 5. The vehicle 5 may be a hybrid vehicle (HV), a plug-in hybrid electric vehicle (PHEV) or a battery electric vehicle (BV). The vehicle 5 in the present embodiment is an automobile, but the coolant manifold 1 may be employed in other types of vehicle.

As shown in Figure 2, the electric motor 3 comprises at least one coolant manifold 1, a stator 7, a rotor 9 and a housing 11. The stator 7 comprises a plurality of stator windings 13 (shown schematically in Figure 2). The stator windings 13 may, for example, comprise hairpin windings. As shown in Figure 3, the stator windings 13 comprise associated electrical connectors 15 disposed in a chamber CH formed at a first end of the housing 11. In a variant, the stator windings 13 may be welded to each other. Alternatively, or in addition, the stator windings 13 may comprise a continuous winding which is formed to the desired shape.

The housing 11 in the present embodiment houses the complete electric drive unit (EDU) which comprises the electric motor 3, a gearbox (not shown) and an inverter (not shown). In a variant, the housing 11 may be a dedicated housing for the electric motor 3. A circular aperture 17 is formed inside the housing 11 for receiving the coolant manifold 1. The circular aperture 17 comprises a cylindrical recess in which the coolant manifold 1 locates. At least one coolant manifold 1 is located in the circular aperture 17 formed in the housing 11. The rotor 9 is mounted to an output shaft 19 connected to a drivetrain of the vehicle 5. The output shaft 19 is rotatable about a rotational axis X. The housing 11 is generally cylindrical and has a central longitudinal axis which is coincident the rotational axis X of the output shaft 19. The electric motor 3 comprises a coolant system (not shown) for introducing a coolant for cooling the stator windings 13 and/or the electrical connectors 15. The coolant is a liquid which, in the present embodiment, is oil. Other coolants may be used. The coolant system comprises a coolant supply port 23 for supplying the coolant to the housing 11; and a coolant outlet port 25 for discharging the coolant from the housing 11. The coolant may be circulated through a heat exchanger (not shown) to reject thermal energy. The coolant supply port 23 and the coolant outlet port 25 in the present embodiment are diametrically opposed from each other. The coolant supply port 23 and is configured to introduce the coolant onto the coolant manifold 1. The coolant supply port 23 is disposed at the top of the housing 11 and the coolant outlet port 25 is disposed at the bottom of the housing 11. Other positions are contemplated for the coolant supply port 23 and/or the coolant outlet port 25.

The coolant manifold 1 is configured to distribute the coolant supplied to the electric motor 3. In particular, the coolant manifold 1 is configured to distribute the coolant introduced through the coolant supply port 23 over the stator windings 13 and/or the electrical connectors 15. The coolant manifold 1 helps provide more uniform distribution of the coolant over the electrical conductors. The coolant manifold 1 in the present embodiment is configured for use with different positions and/or orientations of the coolant supply port 23. The coolant manifold 1 may help to reduce the inlet speed of the coolant. The reduced inlet speed may help reduce damage to the electrical insulation provided on the electrical connectors 15 and/or the stator windings 13.

As shown in Figures 5 and 6, the coolant manifold 1 comprises a locating band 31 having a closed profile for locating the coolant manifold 1 in the circular aperture 17 formed in the housing 11 of the electric motor 3. The locating band 31 has a closed profile comprising an at least substantially continuous curve. The locating band 31 is resiliently deformable. The locating band 31 in the present embodiment is moulded from a glass fibre reinforced polymer (GFRP). The coolant gallery 33 in the present embodiment is moulded for a GFRP. The whole of the coolant manifold 1 of the present embodiment is made of a GRFP. A suitable material for forming the coolant manifold 1 including the locating band 31 and/or the coolant gallery 33 is PA6 GF30. The glass fibres in the GFRP may reduce creep over the life of the component, thereby helping to maintain resilience. Other materials may be used to form the locating band 31 and/or the coolant gallery 33 and/or the whole of the coolant manifold 1.

The locating band 31 is described herein with reference to an undeformed (unloaded or neutral) state when no external force is applied; and with reference to a deformed (loaded) state when an external force is applied. The locating band 31 is shown in the undeformed state in Figure 7A; and in the deformed state in Figure 7B. The profile of the locating band 31 is described herein with reference to a plane extending perpendicular to the central longitudinal axis X (i.e. the plane of the page in Figures 7A and 7B). The locating band 31 comprises a major axis al and a minor axis bl which are perpendicular to each other. The locating band 31 also comprises a central longitudinal axis cl which is perpendicular to the major axis al and the minor axis lot The central longitudinal axis CI extends out of the plane of the page in Figure 6. In the undeformed state, the locating band 31 is non-circular. In the present embodiment, the closed profile of the locating band 31 comprises an ellipse shape in the undeformed state. A first dimension (height) dl of the locating band 31 along the major axis al is greater than a second dimension (width) d2 of the locating band 31 along the minor axis b1. The first dimension dl may be greater than the width d2 by less than or equal to 1%, 2% or 5%, for example. In the present embodiment, the first dimension dl is 231.5mm and the width d2 Is 229.5mm. An external force is applied to the locating band 31 in a radial direction along the major axis al to deform the locating band 31 for insertion into the circular aperture 17. In particular, the locating band 31 is compressible along the major axis al. The locating band 31 may be compressible along the minor axis b1 and/or other axes (not shown). The locating band 31 is compressed along the major axis al. In the deformed state, the locating band 31 is at least substantially circular. The substantially circular shape of the locating band 31 in the deformed state makes the locating band 31 shape suitable for insertion into the circular aperture 17 formed in the housing 11. The first dimension dl of the locating band 31 along the major axis al and the width d2 of the deformed locating band 31 of the locating band 31 along the minor axis bl are at least substantially equal to each other in this deformed state. The diameter of the locating band 31 when deformed into a circle is at least substantially equal to the diameter of the circular aperture 17 in the housing 11. In a variant, the closed profile of the locating band 31 may comprise an oval shape in the undeformed state.

The fitment through deformation of the locating band advantageously reduces the need for fixings within the housing. Furthermore, the fitment seals the manifold in the upper segment of the housing. Additionally, the fitment allows the locating band to lock into position in the housing and prevent rotation through an alignment feature as will be discussed. As a result, the manifold provides a number of advantages with a minimal design that is quick and easy to install in the housing.

The coolant manifold 1 comprises a coolant gallery 33. The coolant gallery 33 comprises an elongated channel 34 for receiving the coolant. The coolant gallery 33 is formed in an upper quadrant of the coolant manifold 1 and comprises an arc extending through approximately 90°. In an embodiment shown the coolant gallery 33 is coincident with the major axis al of the locating band 31. In other embodiments the coolant gallery 33 may be coincident with the minor axis 131 or may be positioned between the major and minor axes al, b1. In the present embodiment, the major axis al of the coolant band 31 bisects the coolant gallery 33. The coolant gallery 33 comprises an inlet aperture 35 for receiving coolant from the coolant supply port 23; and a plurality of outlet apertures 37 for discharging coolant from the coolant gallery 33. The coolant gallery 33 comprises five (5) outlet apertures 37 in the present embodiment. The outlet apertures 37 are symmetrical about the major axis al of the locating band 31. The outlet apertures 37 may be configured such that the discharge of the coolant onto the electrical connectors 15 and/or stator windings 13 is a drip or a continuous flow of the coolant.

The coolant gallery 33 is formed by a peripheral wall 39 (known as a gallery wall) around the elongated channel. The gallery wall 39 having a radially outer surface 41 for engaging a cylindrical sidewall 43 of the housing 11 (as shown in Figure 3). The compression of the locating band 31 generates a spring force for biasing a radially outer surface 41 of the gallery wall) towards the sidewall housing 11 when the locating band 31 is inserted into the circular aperture 17 of the housing 11.

The gallery wall 39 extends substantially continuously around an outside of the coolant gallery 33. The outer surface 41 of the gallery wall 39 engages the sidewall 43 along the length of the gallery wall 39. The engagement of the gallery wall 39 on the sidewall 43 may at least partially seal the coolant gallery 33. The locating band 31 and the coolant gallery 33 are moulded integrally in the present embodiment. In a variant, the locating band 31 and the coolant gallery 33 may be separate components.

As shown in Figure 5, the locating band 31 in the present embodiment comprises first and second annular frame members 45-1, 45-2 spaced apart from each other along the central longitudinal axis X. A plurality of support struts 47 extend between the first and second annular frame members 45-1, 45-2. As shown in Figure 6, at least one coolant drainage aperture 49 is formed at the bottom of the locating band 31. In the present embodiment, the locating band 31 comprises three coolant drainage apertures 49. The coolant drainage apertures 49 each comprise a concave section formed in the first annular frame member 45-1. The coolant drainage apertures 49 are formed diametrically opposed from the coolant gallery and are arranged to allow the coolant to drain from the housing 11.

As shown in Figure 8 and 9, the housing 11 and the coolant manifold 1 of the locating band 31 optionally comprise one or more alignment feature 51 for aligning the coolant manifold 1 with the housing 11. The alignment of the coolant manifold 1 is at a predefined angular alignment based on the position of the one or more alignment feature 51 of the coolant manifold 1 and one or more alignment feature 53 formed in the housing 11. In the present embodiment, the coolant manifold 1 alignment feature 51 comprises a projection 51 formed on the locating band 31 which engages with the recess 53 formed in the housing 11. The projection 51 is elongated in a circumferential direction and locates in the recess 53 when the coolant manifold 1 is in the predefined angular orientation relative to the housing 11.

The coolant manifold 1 wherein the locating band 31 optionally comprises a one or more coolant guides 55, as shown in Figures 6 and 8. Each coolant guide 55 comprises a fin which extends radially inwardly. The coolant guides are configured to guide the coolant discharged from the coolant gallery 43.

The coolant manifold 1 is installed in the circular aperture 17 by applying an external force to compress the locating band 31 along the major axis al. In the deformed state, the profile of the locating band 31 and the coolant gallery 33 at least substantially matches the profile of the circular aperture 11. The coolant manifold 1 is then displaced along the central longitudinal axis X to locate the coolant manifold 1 in the circular aperture 11. The compression of the locating band 31 generates a spring force which acts to bias the radially outer surface 41 of the gallery wall 39 towards the housing sidewall 43 of the circular aperture 17. The spring force on the sealing face generates a friction force against the housing 11 which will help to maintain the axial location of the coolant manifold 1.

The coolant gallery 33 is formed by a gallery wall 39 having a radially outer surface 41 for engaging a cylindrical sidewall 43 of the housing 11 which defines the circular aperture 17.

In use, the coolant is supplied to the coolant supply port 23 of the electric motor 3. The coolant is introduced into the coolant gallery 33. The coolant supplied to the coolant manifold 1 is distributed through the configured one or more outlet apertures 37 to distribute the coolant over the stator windings 13 and/or the electrical connectors 15. In particular, the coolant manifold 1 is configured to discharge the coolant through the outlet apertures 37. The coolant is distributed from the coolant gallery 43 over the stator windings 13 and/or the electrical connectors 15. The coolant is removed through the housing 11 through the coolant drainage apertures 49 and recirculated.

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.

The present invention has been described with reference to a coolant manifold 1 having a locating band 31 having a closed profile. In a variant, the coolant manifold 1 may comprise one or more locating member (not shown) having an open profile, for example comprising a C-shaped profile (which is non-circular in an undeformed state). The locating member(s) may act on the sidewall of the circular aperture to apply a spring force in a radial direction to bias the coolant gallery 33 towards the cylindrical sidewall 43 of the housing 11. Alternatively, or in addition, the locating member(s) may cooperate with one or more reaction surface to apply the biasing force. The one or more reaction surface may be defined by the housing 11.

Alternatively, or in addition, the one or more reaction surface may be defined by an insert located in the circular aperture. The insert and the locating band 31 could collectively form a closed profile equivalent to the arrangement described herein.

Claims

CLAIMS1. A coolant manifold for distributing coolant within an electric motor, the coolant manifold comprising: a locating band having a closed profile for locating the coolant manifold in a circular aperture formed in a housing of the electric motor; the locating band being resiliently deformable and, in an undeformed state, having a first dimension along a major axis which is greater than a second dimension along a minor axis, wherein the major axis is substantially perpendicular to the minor axis; wherein the locating band is compressible along the major axis for insertion into the circular aperture formed in the housing, the compression of the locating band generates a spring force for biasing a radially outer surface of a gallery wall towards the sidewall of the housing when the locating band is inserted into the circular aperture.
2. A coolant manifold as claimed in claim 1 comprising a coolant gallery coincident with the major axis of the locating band, the coolant gallery comprising an inlet aperture for receiving a coolant from a coolant supply and a plurality of outlet apertures for discharging coolant from the coolant gallery, the coolant gallery being formed by the gallery wall having a radially outer surface for engaging a sidewall of the housing.
3. A coolant manifold as claimed in claim 2, wherein the major axis of the locating band bisects the coolant gallery.
4. A coolant manifold as claimed in claim 2 or claim 3, wherein the locating band comprises one or more coolant drainage aperture diametrically opposed from the coolant gallery.
5. A coolant manifold as claimed in any one of claims 2, 3 or 4, wherein the locating band comprises one or more coolant guides for guiding the coolant discharged from the coolant gallery.
6. A coolant manifold as claimed in any one of claim 2 to claim 5, wherein the coolant gallery comprises an arc extending through approximately 90°.
7. A coolant manifold as claimed in any one of the preceding claims, wherein the closed profile of the locating band comprises a substantially continuous curve.
8. A coolant manifold as claimed in any one of the preceding claims, wherein the closed profile of the locating band comprises an ellipse shape or an oval shape in the undeformed state.
9. A coolant manifold as claimed in any one of the preceding claims, wherein the locating band comprises: a first annular frame member and a second annular frame member spaced apart from each other along a central longitudinal axis extending perpendicular to the major axis and the minor axis; and a plurality of supports extending between the first and second frames.
10. A coolant manifold as claimed in any one of the preceding claims, wherein the locating band comprises one or more alignment features for aligning the coolant manifold with the housing.
11. A coolant manifold as claimed in any one of the preceding claims, wherein the coolant manifold is moulded from a fibre reinforced polymer.
12. An electric motor comprising a housing and at least one coolant manifold as claimed in any one of the preceding claims, the at least one coolant manifold being located in a circular aperture formed in the housing.
13. An electric motor as claimed in claim 11 comprising a stator having a plurality of stator windings and associated electrical connectors, wherein the at least one coolant manifold is configured to discharge coolant onto the electrical connectors.
14. A vehicle comprising one or more electric motor as claimed in claim 12 or claim 13.