WO2021116648A1

WO2021116648A1 - Electric drive unit

Info

Publication number: WO2021116648A1
Application number: PCT/GB2020/052561
Authority: WO
Inventors: Matthew Kelly; Shunichi Ishikawa; Guangtai ZHENG
Original assignee: Dyson Technology Limited
Priority date: 2019-12-13
Filing date: 2020-10-14
Publication date: 2021-06-17
Also published as: GB201918371D0; CN114786979A; GB2590382B; GB2590382A

Abstract

A vehicle (100) having an electric drive unit (102), the electric drive unit (102) having an elongate axis (110), a gearbox (104), an electric motor (106) mounted to the gearbox (104) and configured to provide drive to the gearbox (104), and a inverter (108) mounted to the gearbox (104) and configured to provide drive current to the electric motor (106). The elongate axis (110) is orthogonal to both input and output rotational axes of the gearbox (104). The electric drive unit (102) has first (134), second (135) and third (140) mounts that connect the electric drive unit (102) to a body of the vehicle (100) at respective first, second and third mounting points thereof, such that the electric drive unit' s elongate axis (110) is at a pitch angle greater than 45°.

Description

ELECTRIC DRIVE UNIT

Field of the Invention

The present invention relates to an electric vehicle having an electric drive unit (EDU).

Background of the Invention

Electric and hybrid electric vehicles are becoming increasingly common. One such vehicle may comprise at least one electric drive unit (EDU), each driving a corresponding pair of road wheels. The EDU may include a gearbox and electric motor. The electric motor may be supplied with drive current by an inverter.

It would be desirable to provide an electric vehicle having an improved mounting arrangement for at least one electric drive unit, preferably having improved packaging and/or safety characteristics, and/or reduced manufacturing cost and/or complexity.

Summary of the Invention

The present invention provides a vehicle comprising an electric drive unit, the electric drive unit having an elongate axis and comprising: a gearbox; an electric motor mounted to the gearbox and configured to provide drive to the gearbox; an inverter mounted to the gearbox and configured to provide drive current to the electric motor; wherein the elongate axis is orthogonal to both input and output rotational axes of the gearbox, and the electric drive unit comprises first, second and third mounts that connect the electric drive unit to a body of the vehicle at respective first, second and third mounting points thereof, such that the electric drive unit’ s elongate axis is at a pitch angle, the pitch angle being greater than 45°.

The pitch angle is measured relative to a lower surface of the vehicle body that is substantially parallel to a surface upon which the vehicle is disposed in use.

The use of three mounts and a pitch angle greater than 45° may result in an improved mounting arrangement for at least one electric drive unit. Depending upon the specific implementation, these features may provide improved packaging and/or safety characteristics, and/or reduced cost and/or complexity.

The first and second mounting points may bear a majority, or substantially all, of the electric drive unit’s weight via the respective first and second mounts, which may result in reduced manufacturing cost and/or complexity, and/or improved distribution of various forces acting on the electric drive unit in use.

The third mounting point may be a torque reaction point, which may result in reduced manufacturing cost and/or complexity. This may also provide improved distribution of forces acting on the electric drive unit in use.

The electric drive unit may be mounted such that its elongate axis is substantially vertical. The additional longitudinal space provided by this arrangement compared to, for example, a horizontal electric drive unit arrangement, may provide improved packaging characteristics, as well as the option of providing improved safety characteristics by increasing a crumple zone of the vehicle. Vertical here will be understood not to mean exactly vertical, but rather encompassing a range of angles, for example between 70-110 degrees. The first and second mounts may be positioned higher than the third mount. This may provide for stable mounting of the electric drive unit, reduced cost and/or complexity, and/or improved distribution of various forces acting on the electric drive unit in use.

The inverter may be mounted to a first lateral side of the gearbox, and the electric motor may be mounted to a second lateral side of the gearbox opposite the first lateral side. This may provide a relatively compact and balanced arrangement.

The first mount may form part of, or be attached to, the inverter. This may provide a convenient and compact mounting arrangement on the inverter side of the electric drive unit.

The second mount may form part of, or be attached to, the electric motor. This may provide a convenient and compact mounting arrangement on the electric motor side of the electric drive unit.

The electric drive unit may be substantially T-shaped in front elevation, wherein the first and second mounts are positioned at opposite ends of a crossbar of the T-shape, and the gearbox forms an upright of the T-shape. This may provide for a convenient and compact mounting arrangement. The elongate axis extends lengthways through the upright of the T-shape.

The third mount may be disposed in front of a lower portion of the upright. This may provide for a convenient and compact mounting arrangement, and/or improved distribution of various forces acting on the electric drive unit in use.

The gearbox may comprise output shafts for driving wheels of the vehicle, wherein a centre of gravity of the first electric drive unit is above the output shafts. This may provide a convenient and compact mounting arrangement. The electric drive unit may be configured to drive a pair of front wheels of the vehicle.

Each of the first, second and third mounts may comprise a respective elastomeric mount and/or a respective mount bracket.

The vehicle may comprise a further electric drive unit having a further elongate axis and comprising: a further gearbox; a further electric motor mounted to the further gearbox and configured to provide drive to the further gearbox; and a further inverter mounted to the further gearbox and configured to provide drive current to the further electric motor; wherein the further elongate axis is orthogonal to both input and output rotational axes of the further gearbox, and the further electric drive unit is mounted with the further elongate axis at a further pitch angle, the further pitch angle being less than the pitch angle.

The further electric drive unit may be mounted such that its elongate axis is substantially horizontal. Horizontal mounting may allow for the provision of greater space above the electric drive unit, which may be particularly useful when the further electric drive unit is positioned below a load space of the vehicle, for example. Horizontal here will be understood not to mean exactly horizontal, but rather encompassing a range of angles, for example between 0-30 degrees.

The further electric drive unit may be configured to drive a pair of rear wheels of the vehicle.

The further electric drive unit may comprise a plurality of combined weight-bearing and torque-reaction mounts that connect the further electric drive unit to the body of the vehicle at corresponding mounting points thereof. This may provide a convenient and compact alternative mounting arrangement, which may be particularly useful when the further electric drive unit is positioned below a load space of the vehicle, for example.

The further electric drive unit may comprise fourth, fifth, sixth and seventh mounts that mount the further electric drive unit to the body of the vehicle at respective fourth, fifth, sixth and seventh mounting points thereof. This may provide a convenient and compact alternative mounting arrangement, which is particularly useful when the further electric drive unit is positioned below a load space of the vehicle, for example.

All mounts of the further electric drive unit may bear a portion of the further electric drive unit’s weight. This may provide a convenient and compact alternative mounting arrangement, which may be particularly useful when the further electric drive unit is positioned below a load space of the vehicle, for example.

Each of the fourth, fifth, sixth, and seventh mounts may comprise a respective elastomeric mount and/or a mounting bracket. At least two of the fourth, fifth, sixth and seventh mounts may comprise a common bracket.

The fourth, fifth, sixth, and seventh mounts may be disposed in substantially the same plane.

The electric drive unit may be a front electric drive unit having one mount on each of the inverter, motor, and gearbox. Alternatively, or in addition, the further electric drive unit may be a rear electric drive unit that has one mount on each of the motor and the inverter, and two mounts on the gearbox. These may provide convenient and compact mounting arrangement.

Any of the mounts may take the form of, or include, a bracket attached to the electric drive unit. Alternatively, any of the mounts may form part of the electric drive unit, such as forming part of the electric motor, inverter, or gearbox. Brief Description of the Drawings

In order that the present invention may be more readily understood, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a partially see-through side view of a vehicle comprising a front- mounted electric drive unit (EDU) and a further rear-mounted EDU; Figure 2 is a partially see-through front view of the vehicle of Figure 1, showing the front-mounted EDU of Figure 1;

Figure 3 is a partially see-through rear view of the vehicle of Figure 1, showing the further EDU of Figure 1;

Figure 4 is a left elevation of the front-mounted EDU; Figure 5 is a right elevation of the front-mounted EDU;

Figure 6 is a perspective view of the front-mounted EDU, with mounts omitted for clarity;

Figure 7 is a further perspective view of the front-mounted EDU;

Figure 8 is a perspective view of the front-mounted EDU showing its attachment to a front subframe of the vehicle;

Figure 9 is a left elevation of a further EDU;

Figure 10 is a right elevation of the further EDU of Figure 9;

Figure 11 is a perspective view of the further EDU, with mounts omitted for clarity; Figure 12 is a further perspective view of the further EDU;

Figure 13 is a plan view of the further EDU;

Figure 14 is a plan view of the further EDU, mounted to a rear subframe of the vehicle of Figure 1. Detailed Description of the Invention

Referring to the drawings, a vehicle 100 comprises an electric drive unit (EDU) in the form of an EDU 102. The EDU 102 includes a gearbox 104. An electric motor 106 is mounted to the gearbox 104 and configured to provide drive to an input shaft (not shown) of the gearbox 104. A inverter in the form of an inverter 108 is mounted to the gearbox 104 and configured to provide drive current to the electric motor 106.

In the embodiment shown, the electric motor 106 is mounted to a first lateral side of the gearbox 104, and the inverter 108 is mounted to a second lateral side of the gearbox 104 opposite the first lateral side.

The EDU 102 has an elongate axis 110 extending generally through the gearbox 104. As best shown in Figures 2 and 4 to 7, the elongate axis 110 is defined in this embodiment as an axis orthogonal to both the input and output rotational axes of the gearbox 104. The elongate axis 110 extends generally through the center line through the gearbox 104. As best shown in Figure 2 the EDU is substantially T-shaped in front elevation, and the elongate 110 axis generally extends with the upright of the T-shape.

In the illustrated embodiment, the EDU 102 comprises a first mount bracket 134 bolted directly to the first inverter 108 by way of bolts 142 screwed into corresponding threaded bosses 144 (see Figure 6) on the inverter 108. The EDU 102 comprises a second mount bracket 135 bolted directly to the electric motor 106 by way of bolts 152 screwed into corresponding threaded bosses 153 (see Figure 7) on the electric motor 106. The first and second mount brackets 134 and 135 are positioned at opposite ends of a crossbar of the T-shape, and the gearbox 104 forms an upright of the T-shape.

As best shown in Figures 4, 5 and 8, a third mount bracket 140 is bolted to a lower end of the gearbox 104 by way of bolts 145 screwed into corresponding threaded bosses 147. In the illustrated embodiment, the third mount bracket 140 is disposed in front of a lower portion of the upright of the T-shape.

In the illustrated embodiment, the first mount bracket 134 is attached to the inverter 108. In other embodiments, the first mount bracket 134 may comprise the inverter 108 itself, or may be attached to, or form part of, the gearbox 104. The first mount bracket 134 has an elastomeric mounting portion 131.

Similarly, in the illustrated embodiment, the second mount bracket 135 is attached to the electric motor 106. In other embodiments, the second mount bracket 135 may comprise the electric motor itself, or may be attached to, or form part of, the gearbox 104. The second mount bracket 135 has an elastomeric mounting portion 136.

In the illustrated embodiment, the third mount bracket 140 is attached to the gearbox 104. In other embodiments, the third mount bracket 140 may comprise the gearbox 104 itself, or may be attached to, or form part of, another portion of the EDU 102. The third mount bracket 140 has an elastomeric mounting portion 146.

The vehicle 100 comprises a crossmember 141 that extends between front shock towers 138 of the vehicle 100. The first mount bracket 134 is connected to the vehicle 100 at a mounting point 137 on the crossmember 141 via its elastomeric mounting portion 131., and the second mount 135 is connected to the vehicle 100 at a mounting point 139 on the crossmember 141 via its elastomeric mounting portion 136. In the illustrated embodiment, the mounting points 137 and 139 bear substantially all of the EDU’s weight via the first mount bracket 134 and the second mount bracket 135.

The vehicle 100 comprises a front subframe 133. The third mount bracket 140 is connected to a third mounting point 143 on the subframe 133 (see Figure 8), via its elastomeric mounting portion 146, at a position lower than the first and second mounts 134 and 135. In the illustrated embodiment, the third mounting point 143 is a torque- reaction mounting point that bears substantially none of the EDU’s weight. As can be seen in Figure 8, the elastomeric mounting portion 146 of the third mount bracket 140 is bolted to the subframe 133 at either end of the elastomeric mounting portion 146.

The EDU 102 is mounted with its axis 110 at a pitch angle greater than 45°. In the illustrated embodiment, the pitch angle is substantially vertical. The word “vertical” in this context is used with its ordinary meaning, and is not necessarily limited to exactly 90°.

In the illustrated embodiment, the EDU 102 drives a set of front wheels 130 of the vehicle 100 via respective output shafts 151 of the gearbox 104. A centre of gravity of the EDU 102 is above the output shafts.

In the illustrated embodiment, the vehicle 100 comprises a further EDU 112. The further EDU 112 includes a further gearbox 114. A further electric motor 116 is mounted to the further gearbox 114 and configured to provide drive to an input shaft (not shown) of the further gearbox 114. A further inverter in the form of a further inverter 118 is mounted to the further gearbox 114 and configured to provide drive current to the further electric motor 116.

In the embodiment shown, the further electric motor 116 is mounted to a first lateral side of the further gearbox 114, and the further inverter 118 is mounted to a second lateral side of the further gearbox 114 opposite the first lateral side. As best shown in Figure 13 the further EDU is substantially T-shaped in plan.

The further EDU 112 has a further elongate axis 120 extending generally through the further gearbox 114. As best shown in Figures 9 and 10, the elongate axis 120 is defined as an axis orthogonal to both the input and output rotational axes of the further gearbox 114. The elongate axis 110 extends generally through the center line through the gearbox The further EDU 112 is mounted with its further elongate axis 120 at a further pitch angle, which may be less than 45°. In the illustrated embodiment, the further pitch angle is approximately horizontal. The word “horizontal” in this context is used with its ordinary meaning, and is not necessarily limited to exactly 0°.

In the illustrated embodiment, the further EDU comprises a fourth mount bracket 156, a fifth mount bracket 158, and a sixth mount bracket 160.

The fourth mount bracket 156 is bolted directly to the further inverter 118 by way of bolts 164 (see Figures 9, 13 and 14) screwed into corresponding threaded bosses 166 (see Figure 11) on the further inverter 118. The fourth mount bracket 156 attaches to a fourth mounting point 157 disposed on a rear subframe 150 (see Figure 14) of the vehicle 100 via its elastomeric mounting portion 173.

The fifth mount bracket 158 is bolted directly to the further electric motor 116 by way of bolts 168 (see Figure 10) screwed into corresponding threaded bosses 170 (see Figure 12) on the further electric motor 116. The fifth mount bracket 158 attaches to a fifth mounting point 159 disposed on the rear subframe 150 of the vehicle 100 via its elastomeric mounting portion 174.

The fourth and fifth mount brackets 156 and 158 are positioned at opposite ends of a crossbar of a T-shape formed by the further EDU 112 in plan (see Figure 13). The gearbox 114 forms an upright of the T-shape.

The sixth mount bracket 160 is a common bracket for two elastomeric mounting portions 175,176. The sixth mount bracket 160 is bolted directly to the further gearbox 114 by way of threaded bolts 165 (see Figures 9, 10, 13 and 14) screwed into corresponding threaded bosses 161 (see Figures 11 and 12). The sixth mount bracket 160 attaches to sixth and seventh mounting points 171,172 disposed on the rear subframe 150 of the vehicle 100 via its elastomeric mounting portions 175,176.

Each of the fourth, fifth, and sixth mount brackets 156, 158, 160 is a combined weight bearing and torque-reaction mount that connects the further EDU 112 to the vehicle 100 at its corresponding mounting point.

In the illustrated embodiment, the further EDU 112 is configured to drive a pair of rear wheels 132 of the vehicle.

Mounts for the front-mounted EDU 102 may consist solely of first, second and third elastomeric mounts in the specific geometric relationships illustrated. There are specific advantages that flow from providing a first weight-bearing mount on a first upper lateral side of the EDU, a second weight-bearing mount on a second upper lateral side of the EDU opposite the first upper lateral side of the EDU, and a third torque-reaction mount at a lower end of the EDU. These advantages include effective mounting of the EDU to the vehicle, and especially a front end of the vehicle, in a compact manner that may result in production and installation efficiencies.

Similarly, mounts for the rear-mounted EDU 112 may consist solely of first, second, third and fourth mounts (corresponding to the illustrated fourth, fifth, sixth and seventh elastomeric mounts in the illustrated embodiment) in the specific geometric relationships illustrated. There are specific advantages that flow from providing a first weight-bearing and torque-reaction mount on a first lateral side of the EDU, a second weight-bearing and torque-reaction mount on a second lateral side of the EDU opposite the first lateral side of the EDU, and third and fourth weight-bearing and torque-reaction mounts at an end of the EDU opposite that to which the first and second mounts are located. These advantages include effective mounting of the EDU to the vehicle, and especially a rear end of the vehicle, in a compact manner that may result in production and installation efficiencies. The skilled person will appreciate that each mount may be attached to its respective mounting point with multiple bolts via its respective elastomeric portion. In the illustrated embodiment, the EDU 102 attaches to the vehicle at three attachment points via its three elastomeric mounting portions and the EDU 112 attaches to the vehicle at four attachment points via its four elastomeric mounting portions.

In other embodiments, the mounting points 137 and 139 bear a majority of the EDU’s weight, with the third mounting point 143 bearing the remainder of the weight while still acting as a torque-reaction point. It will be appreciated that other combinations of weight- bearing and/or torque-reaction mounts and mounting points may be employed, depending upon packaging and engineering requirements, for example.

Although the illustrated vehicle 100 is a car, the invention may find application in other types of vehicles, such as trucks and vans.

Although the invention has been described with reference to specific examples, it will be appreciated that the invention may be embodied in many other forms that fall within the scope of the appended claims.

Claims

1. A vehicle comprising an electric drive unit, the electric drive unit being substantially T-shaped in front elevation and comprising: a gearbox forming an upright of the T-shape, wherein an elongate axis of the drive unit is orthogonal to both input and output rotational axes of the gearbox, and extends lengthways through the upright of the T-shape; an electric motor mounted to the gearbox and configured to provide drive to the gearbox; an inverter mounted to the gearbox and configured to provide drive current to the electric motor; wherein the electric drive unit comprises first, second and third mounts that connect the electric drive unit to a body of the vehicle at respective first, second and third mounting points thereof such that the elongate axis is oriented at a pitch angle to a surface of the body that is substantially parallel to a flat surface upon which the vehicle is disposed in use, the pitch angle being greater than 45°; and wherein the first and second mounts are positioned at opposite ends of a crossbar of the T-shape.

2. The vehicle of any preceding claim, wherein the electric drive unit is mounted such that its elongate axis is substantially vertical.

3. The vehicle of any preceding claim, wherein the first and second mounts are positioned higher than the third mount.

4. The vehicle of any preceding claim, wherein the inverter is mounted to a first lateral side of the gearbox, and the electric motor is mounted to a second lateral side of the gearbox opposite the first lateral side.

5. The vehicle of any preceding claim, wherein the first mount forms part of, or is attached to, the inverter.

6. The vehicle of any preceding claim, wherein the second mount forms part of, or is attached to, the electric motor.

7. The vehicle of any preceding claim, comprising one or more output shafts for driving wheels of the vehicle, wherein a centre of gravity of the first electric drive unit is above the one or more output shafts.

8. The vehicle of any preceding claim, wherein the electric drive unit is configured to drive a pair of front wheels of the vehicle.

9. The vehicle of any preceding claim, comprising a further electric drive unit having an elongate axis and comprising: a further gearbox; a further electric motor mounted to the further gearbox and configured to provide drive to the further gearbox; and a further inverter mounted to the further gearbox and configured to provide drive current to the further electric motor; wherein the further electric drive unit is mounted with its elongate axis at a further pitch angle, the pitch angle of the further electric drive unit being less than the pitch angle of the electric drive unit.

10. The vehicle of claim 9, wherein the further electric drive unit is mounted such that its elongate axis is substantially horizontal.

11. The vehicle of claim 9 or 10, wherein the further electric drive unit is configured to drive a pair of rear wheels of the vehicle.

12. The vehicle of any one of claims 9 to 11, wherein the further electric drive unit comprises a plurality of combined weight-bearing and torque-reaction mounts that connect the further electric drive unit to the body of the vehicle at corresponding mounting points thereof.

13. The vehicle of claim 12, wherein the further electric drive unit comprises fourth, fifth, sixth and seventh mounts that mount the further electric drive unit to the body of the vehicle at corresponding mounting points thereof.