EP4732409A1

EP4732409A1 - Electric drive unit having cover system for interacting with high voltage interlock circuit

Info

Publication number: EP4732409A1
Application number: EP24846615.3A
Authority: EP
Inventors: Andrew T. Brammer; Hannah N. MIGLIORE; Scott J. GOBLIRSCH; Aaron L. MINOR; Peter Barta
Original assignee: American Axle and Manufacturing Inc
Current assignee: American Axle and Manufacturing Inc
Priority date: 2023-07-27
Filing date: 2024-07-29
Publication date: 2026-04-29
Also published as: MX2026001030A; WO2025024842A1; CN121713360A

Abstract

A cover system configured for use in an electric drive unit, including a first high voltage interlock (HVIL) terminal configured to electrically couple to a first sensing terminal; a second HVIL terminal configured to electrically couple to a second sensing terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, including a conductor that faces a cavity of the housing; and an intermediate cover member, including spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member; the first ends releasably biased into physical and electrical engagement with the conductor, the second ends releasably biased into physical and electrical engagement with the first HVIL terminal or the second HVIL terminal.

Description

ELECTRIC DRIVE UNIT HAVING COVER SYSTEM FOR INTERACTING WITH

HIGH VOLTAGE INTERLOCK CIRCUIT

PRIORITY CLAIM

[0001] The present application claims priority to previously-filed provisional application number 63/529,223 filed July 27^th, 2023 the contents of which are incorporated by reference.

FIELD

[0002] The present disclosure relates to an electric drive unit having a cover system for interacting with a high-voltage interlock circuit.

BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] There is increasing level of interest on the part of vehicle manufacturers to incorporate electric motors into the vehicle drivetrain. As such electric motors are typically provided with relatively high voltage and current electrical power, there is a desire to interrupt the supply of electrical power to an electric motor in situations where the high-power electric conductors are exposed, such as the high-power electric leads of the electric motor. A high-voltage interlock circuit is typically employed in such situations to interrupt the supply of electrical power to the electric leads of the electric motor when the electric leads are exposed. Such high-voltage interlock circuits typically employ discrete switches or sensors to sense the presence of a cover and to interact with circuitry and/or a relay of the high-voltage interlock circuit to interrupt the supply of electrical power when the presence of the cover is not detected. An example of such a system is described in commonly assigned International (PCT) Patent Application No.

PCT/IB2021/052581 filed March 29, 2021, the disclosure of which is incorporated by reference as if fully set forth in detail herein.

[oooq While such configurations are suitable fortheir intended use, the use of discrete switches and/or sensors increases part count, cost and labor.

Accordingly, there remains a need in the art for a high-voltage interlock circuit that does not employ discrete switches or sensors.

SUMMARY pooq In accordance with one implementation, a cover system is configured for use in an electric drive unit, including a first high voltage interlock (HVIL) terminal configured to electrically couple to a first sensing terminal; a second HVIL terminal configured to electrically couple to a second sensing terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, including a conductor that faces a cavity of the housing; and an intermediate cover member, configured to releasably couple to the housing, including spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member; the first ends releasably biased into physical and electrical engagement with the conductor, the second ends releasably biased into physical and electrical engagement with the first HVIL terminal or the second HVIL terminal.

[0007] In accordance with another implementation, a cover system is configured for use in an electric drive unit, including: an electric motor cover assembly, having: a first high voltage interlock (HVIL) motor terminal configured to electrically couple to a first sensing terminal; a second HVIL motor terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, including a conductor that faces a cavity of the housing; an intermediate cover member, induding spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member, wherein the first ends are releasably biased into physical and electrical engagement with the conductor, the second ends are releasably biased into physical and electrical engagement with the first HVIL motor terminal or the second HVIL motor terminal; a first HVIL inverter terminal electrically coupled to the second HVIL motor terminal; a second

HVIL inverter terminal configured to electrically couple to a second sensing terminal; an inverter cover assembly, including: an inverter cover member configured to releasably couple to the housing of the electric drive unit; an inverter spring dip assembly, coupled to a surface of the inverter cover member, having inverter spring contacts that releasably engage the first HVIL inverter terminal and the second HVIL inverter terminal. [0008] In accordance with another implementation, a cover system is configured for use in an electric drive unit, including: a first high voltage interlock

(HVIL) terminal electrically coupled to a first sensing terminal; a second HVIL terminal electrically coupled to a second sensing terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, including a conductor that faces a cavity of the housing; an intermediate cover member, including spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member, wherein the first ends are releasably biased into physical and electrical engagement with the conductor, the second ends are releasably biased into physical and electrical engagement with the first

HVIL terminal or the second HVIL terminal; and a circuit board, including a sensing circuit having the first sensing terminal and the second sensing terminal, configured to determine whether an HVIL circuit exists in a first mode or a second mode.

DRAWINGS

[0009] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0010] Figure 1 is a block diagram depicting an implementation of a high voltage interlock (HVIL) circuit; [0011] Figure 2 is a sectional view depicting an implementation of a portion of a cover system used with an electric drive unit;

[0012] Figure 3 is a sectional view depicting an implementation of another portion of a cover system used with an electric drive unit;

[0013] Figure 4 is a perspective view depicting a portion of an electric drive unit including an implementation of a cover system constructed in accordance with the teachings of the present disclosure;

[0014] Figure 5 is a perspective view depicting a portion of an electric drive unit including an implementation of a cover system constructed in accordance with the teachings of the present disclosure;

[0014] Figure 6 is a perspective view depicting a portion of an electric drive unit including an implementation of a cover system constructed in accordance with the teachings of the present disclosure; and

[0015] Figure 7 is a perspective view depicting a portion of an electric drive unit including an implementation of a cover system constructed in accordance with the teachings of the present disclosure.

[0016] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0017] With reference to Figure 1 of the drawings, a high voltage interlock

(HVIL) circuit 14, which is a portion of an exemplary electric drive unit 10 (shown in Figures 4-7), that is constructed in accordance with the teachings of the present disclosure, is shown. It will be appreciated that it is well known in the art that the electric drive unit 10 has a housing 12, an electric motor received in the housing

12, a transmission driven by the electric motor, and one or more output members, which can be driven directly by the transmission or through a differential assembly that is disposed in a power path between the transmission and a pair of output members. In this regard, and except as noted below, the electric drive unit 10 could have a configuration of the type that is disclosed in International (PCT)

Patent Application No. PCT/IB2021/052581 filed March 29, 2021.

[0019] The electric drive unit 10 can include the housing 12, the HVIL circuit

14 and a cover system 16. The cover system 16, shown in Figures 2-7, can include an electric motor cover assembly 18, or a combination of the electric motor cover assembly 18 and an inverter cover assembly 20, removably enclosing one or more openings 24 providing access to a cavity within the housing 12. The HVIL circuit

14 can include an electrically conductive pathway within the cover system 16 that can be monitored to determine whether or not the cover system 16 is attached to the housing 12. Further, the electric motor cover assembly 18 and the inverter cover assembly 20 can be arranged such that detaching the electric motor cover assembly 18 and/or the inverter cover assembly 20 from the housing 12 must be done sequentially, providing a threshold amount of time before access to high- voltage electrical components within the housing 12 is possible thereby facilitating the discharge of the high-voltage electrical components before user access.

[0020] The housing 12 is configured to house elements of the electric drive unit 10, such as an electric motor (not shown), a plurality of high-power electric leads (not shown), which electrically couple the electric motor to an inverter (not shown), the HVIL interlock circuit 14, and various elements of the cover system

16, including the electric motor cover assembly 18 and the inverter cover assembly

20. In particular, the housing 12 defines a cavity 22 into which the HVIL circuit 14 and the high-power electric leads are disposed. The cavity 22 can be accessed through one or more openings 24 in the housing 12.

[0021] A block diagram of the HVIL circuit 14 is shown in Figure 1. The

HVIL circuit 14 can include a circuit board 26 having a sensing circuit 28 that includes first and second sensing terminals 30 and 32. The sensing terminals 30,

32 can be implemented using individual pins of a microprocessor that can detect the absence or presence of a voltage signal. For example, the pins can sense a low voltage value, such as 0V, indicating that the HVIL circuit 14 is open, or a high voltage value, such as 5V, indicating that the HVIL circuit 14 is closed. The first and second sensing terminals 30 and 32 are formed of an electrically conductive material, such as copper, and are fixedly coupled to an electric insulator that isolates the high-voltage interlock circuit 14 from the housing 12.

[0022] The HVIL circuit 14 can include a plurality of electrical conductors wired in series, such that the opening of any one of the electrical conductors can render the HVIL circuit 14 non-conductive. The high-voltage interlock circuit 14 operates in a first mode that permits the transmission of electrical power between the inverter and the electric motor when electrical power is transmitted between the first and second sensing terminals 30 and 32. The high-voltage interlock circuit

14 operates in a second mode that inhibits the transmission of electrical power between the inverter and the electric motor when electrical power is not transmitted between the first and second sensing terminals 30 and 32.

[0023] In an implementation, the HVIL circuit 14 can electrically couple the first sensing terminal 30 to a first HVIL motor terminal 36 in the in the electric motor cover assembly 18 which is electrically connected to a second HVIL motor terminal

38 via electrical components that can be disassembled to open the HVIL circuit 14.

The second HVIL motor terminal 38 can be electrically coupled to a first HVIL inverter terminal 30 in the inverter cover assembly 20 in series via a first electrical lead 74. The HVIL circuit 14 can electrically couple the first HVIL inverter terminal

40 in the in the inverter cover assembly 20 to a second HVIL inverter terminal 42 via electrical components that can be disassembled to open the HVIL circuit 14.

The HVIL terminals 36, 38, 40, and 42 can be mechanical coupled and electrically separate from the housing 12. The electrical components included in the electric motor cover assembly 18 and the inverter cover assembly 20 that can be assembled or disassembled to close or open the HVIL circuit 14 will be discussed in more detail below.

[0024] The circuit board 26 can be disposed in the cavity 22 and coupled to the housing 12 such that the first and second sensing terminals 30 and 32 face in an outward direction toward the opening 24 in the housing 12. However, the sensing circuit 28 can be positioned in a variety of locations and electrically connected to the first and second sensing terminals 30, 32 via electrical leads. It should also be appreciated that variations of the HVIL circuit 14 are possible. For example, in some implementations, the HVIL circuit and the cover system can be solely implemented using the components of the electric motor cover assembly 18 rather than a combination of the electric motor cover assembly 18 and the inverter cover assembly 20. In such an implementation, the first sensing terminal 30 can be electrically coupled to the first HVIL motor terminal 36 and the second sensing terminal can be electrically coupled to the second HVIL motor terminal 38 to create an HVIL circuit.

[0025] An implementation of the electric motor cover assembly 18 is shown in Figure 2. The electric motor cover assembly 18 includes an exterior cover member 44 and a conductor assembly 46 having an insulating member 48 and a conductor 50. The exterior cover member 40 is configured to be fixedly but removably coupled to the housing 12 to close a cavity 22 and inhibit access to the high-power electric leads. In this regard, a plurality of threaded fasteners 52

(shown in Figure 4) can be employed to couple the exterior cover member 44 to the housing 12. The insulating member 48 can be fixedly coupled to the exterior cover member 44 in any desired manner, such as with threaded fasteners, adhesives, and/or staking, and is formed of an electrically insulating material. In instances where the exterior cover member 44 is formed of an electrically insulating material, the insulating member 48 may be unitarily and integrally formed with the exterior cover member 44. The conductor 50 can be fixedly coupled to the insulating member 48 in any desired manner, such as overmolding, staking, adhesives, or fasteners, is formed of an electrically conductive material, such as copper, and faces away from the exterior cover member 44 and toward the first and second HVIL motor terminals 36 and 38. [0026] The electric motor cover assembly 18 also includes an intermediate cover assembly 54 having an intermediate cover member 56 and a pair of spring contacts 58. The intermediate cover member 56 is formed of an electrically insulating material and is received in the cavity 22 between the conductor assembly 46 and the first and second HVIL motor terminals 36 and 38. The intermediate cover member 56 can be coupled to the housing 12 in any desired manner, such as a press-fit, and covers the high-power electric leads (i.e., the high-power electric leads are disposed beneath the intermediate cover member 56 so that the intermediate cover member 56 must be removed from the cavity 24 to permit access to the high-power electric leads).

[0027] Each of the spring contacts 58 is formed of an electrically conductive material and is configured to resiliently engage both the conductor 50 and an associated one of the first and second HVIL motor terminals 36 and 38 when both the intermediate cover assembly 54 and the exterior cover member 44 are mounted to the housing 12. The spring contacts 58 are shown in the example provided to have a leaf-spring configuration with a generally U or C-shape that includes a first end 60, which extends from one side of the intermediate cover member 56 and is resiliently engaged to the conductor 50, and a second end 62 that extends from a second, opposite side of the intermediate cover member 50 and is resiliently engaged to the associated one of the first and second sensing terminals 30 and 32. In the example provided, the intermediate cover member 56 is formed by injection molding and is molded onto the spring contacts 58 such that the spring contacts 58 are partially encapsulated into the material that forms the intermediate cover member 56. It will be appreciated, however, that the spring contacts 58 can be formed differently and/or could be coupled to the intermediate cover member 56 in a different manner.

[0028] It will be appredated that both the intermediate cover assembly 54 and the exterior cover member 44 can be removed from the housing 12 to permit the installation and/or electrical coupling of the high-power electric leads to the electric motor. Thereafter, the intermediate cover assembly 54 can be inserted into the cavity 22 and mounted to the housing 12 in a manner that engages each of the spring contacts 58 to the associated one of the first and second HVIL motor terminals 36 and 38. At this stage, the intermediate cover assembly 54 blocks direct access to the high-power electric leads. The exterior cover member 56 is next mounted to the housing 12 to dose the opening 24 in the housing 12, to thereby inhibit access to elements of the electric drive unit 10 that are disposed in the cavity 22, and to electrically couple the ends of the spring contacts 58 that are opposite the first and second HVIL motor terminals 36 and 38 to one another.

[0029] Transmission of electrical power through the sensing circuit 28 of the

HVIL circuit 14, and in particular in an electrical path directly between the first sensing terminal 30, the first HVIL motor terminal 36, a first one of the spring contacts 58, the conductor 50, a second one of the spring contacts 58, and the second HVIL motor terminal 38 causes the high-voltage interlock circuit 14 to operate in the first mode that permits the transmission of electrical power between the inverter and the electric motor. Thereafter, the removal of the exterior cover member 44 to permit access to the cavity 22 effectively electrically decouples the conductor 50 from electrical connection with the spring contacts 58 to interrupt or inhibit the transmission of electrical power through the sensing circuit 28 of the high-voltage interlock drcuit 14, which causes the high-voltage interlock drcuit 14 to operate in the second mode that inhibits the transmission of electrical power between the inverter and the electric motor.

[0030] An implementation of the inverter cover assembly 20 is shown in

Figure 3. The inverter cover assembly 20 can include an inverter cover member

64, an inverter spring dip assembly 66, the first HVIL inverter terminal 40, the second HVIL inverter terminal 42, and an HVIL terminal harness 68.

[0031] The inverter cover member 64 can include the inverter spring clip assembly 66 coupled to a side of the inverter cover member 64 fadng the HVIL inverter terminals 40, 42. The inverter spring clip assembly 66 can include a pair of inverter spring contacts 70 electrically coupled to each other and encapsulated in an insulating member 72. The inverter spring contacts 70 can be partially encapsulated in the insulating member 72 in a variety of different ways, such as by injection molding. The spring contacts 70 are shown in this implementation as articulated blade-type connectors. However, other implementations of spring contacts are possible that also opposably bias the spring contacts toward the first and second HVIL inverter terminals 40, 42 and also are electrically conductive. An electrical conductor (not shown) electrically couples the inverter spring contacts 70 to each other within the insulating member 72. In one implementation, the inverter cover member 64 can be formed from metal and the insulating member 72 can be coupled to one side of the inverter cover member 64 via one or more brackets 74. However, the inverter cover member 64 could be formed from an electrically insulating material such that the inverter spring clip assembly 66 is integrally formed within the inverter cover member 64.

[0032] The HVIL terminal harness 68 can couple to the housing 12 within the cavity 22 and face the inverter cover member 64 to expose the first and second

HVIL inverter terminals 40, 42 to the inverter spring contacts 70. The HVIL terminal harness can include a body formed from an electrically insulating material that at least partially encapsulates the first and second HVIL inverter terminals 40, 42 within the body but exposes at least part of the first and second HVIL inverter terminals 40, 42 so that they are able to releasably contact the inverter spring contacts 70. The HVIL terminal harness 68 also includes a first electrical lead 74 that eledrically couples the first HVIL inverter terminal 40 to the second HVIL motor terminal 38 as well as a second electrical lead 76 that electrically couples the second HVIL inverter terminal 42 to the second sensing terminal 32.

[0033] The inverter cover member 64 is configured to be fixedly but removably coupled to the housing 12 to dose a cavity 22 and inhibit access to the high-power electric leads. In this regard, a plurality of threaded fasteners 52

(shown in Figure 6) can be employed to couple the inverter cover member 64 to the housing 12. The inverter cover member 64 can be removed from the housing

12 to permit the installation and/or electrical coupling of the high-power electric leads to the inverter. Thereafter, the inverter cover member 64 can be positioned over the cavity 22 and mounted to the housing 12 in a manner that engages each of the inverter spring contacts 70 to the assodated one of the first and second HVIL inverter terminals 40 and 42. At this stage, the inverter cover member 64 blocks direct access to the high-power electric leads inhibiting access to elements of the electric drive unit 10 that are disposed in the cavity 22, and to electrically couple the ends of the inverter spring contacts 70 that are opposite the first and second HVIL inverter terminals 40 and 42 to one another. The terms “exterior cover member” and “inverter cover member” have been used in conjunction with specifically identified electrical components received within the housing of an electric drive unit. However, it should be appreciated that the implementations described herein could also be used to cover electrical components within a housing that are different than those specifically detailed here.

[0034] As noted above, the cover system 16 can be configured such that the electric motor cover assembly 18 confines a portion of the inverter cover assembly 20 or vice versa, together with the housing 12 to create sufficient delay between when the HVIL circuit 14 is in the first mode and when it transitions to the second mode during the removal of the cover system 16 from the housing Turning to Figures 4-7, an electric drive unit 10 having a housing 12, an HVIL circuit 14, and a cover system 16 are shown in different states of assembly. Figure 4 depicts the electric drive unit 10 with the electric motor cover assembly 18 and the inverter cover assembly 20 coupled to the housing 12 so that the HVIL circuit 14 operates in a first mode. In this implementation, a portion of the electric motor cover assembly 18 engages an outer surface of the inverter cover assembly 20, also referred to as an interference surface 78, preventing the removal of the inverter cover assembly 20 without first removing the electric motor cover assembly 18. [0035] Figure 5 depicts the electric drive unit 10 with the exterior cover member 44 removed from the housing 12 thereby disengaging the conductor 50 from the first end 60 of the spring contacts 58. This transitions the HVIL circuit 14 into the first mode as the disengagement of the conductor 50 from the spring contacts 58 open the circuit 14. After removal of the exterior cover member 44, interference surface 78 no longer constrains the inverter cover member 64 against the housing 12. As shown in Figures 6 and 7, the fasteners 52 can be removed permitting removal of the inverter cover member 64 from the housing 12.

[0036] Despite the removal of the exterior cover member 44 from the housing 12, it is possible for the HVIL circuit 14 to remain conductive for a period of time. In one implementation, this period of time can be less than five seconds.

The interference surface 78 can prevent the simultaneous removal of the exterior cover member 44 and the inverter cover member 64. That is, after removal of the exterior cover 44, the subsequent removal of the inverter cover 64 should consume an amount of time that extends beyond the period of time the HVIL circuit 14 could remain charged.

[0037] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

IN THE CLAIMS:

1. A cover system configured for use in an electric drive unit, comprising: a first high voltage interlock (HVIL) terminal configured to electrically couple to a first sensing terminal; a second HVIL terminal configured to electrically couple to a second sensing terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, including a conductor that faces a cavity of the housing; and an intermediate cover member, configured to releasably couple to the housing, including spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member, wherein the first ends are releasably biased into physical and electrical engagement with the conductor, the second ends are releasably biased into physical and electrical engagement with the first

HVIL terminal or the second HVIL terminal.

2. The cover system recited in claim 1 , wherein the cover system includes an

HVIL circuit existing in a first mode when the conductor physically and electrically engages the first ends and the second ends of the first HVIL terminal and the second HVIL terminal or a second mode when the conductor physically and electrically disconnects from the first ends or the second ends disengage from the first HVIL terminal or the second HVIL terminal.

3. The cover system recited in claim 1 , further comprising the electric drive unit and the housing.

4. The cover system redted in daim 1 , wherein the spring contacts have a substantially C- or U-shape.

5. The cover system recited in claim 1 , wherein the conductor is attached to the exterior cover member via an insulator.

6. The cover system redted in daim 1 , wherein the exterior cover member couples to the housing via a plurality of fasteners to dose an opening in the housing.

7. A cover system configured for use in an electric drive unit, comprising: an electric motor cover assembly, induding: a first high voltage interlock (HVIL) motor terminal configured to electrically couple to a first sensing terminal; a second HVIL motor terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, induding a conductor that faces a cavity of the housing; an intermediate cover member, including spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member, wherein the first ends are releasably biased into physical and electrical engagement with the conductor, the second ends are releasably biased into physical and electrical engagement with the first HVIL motor terminal or the second HVIL motor terminal; a first HVIL inverter terminal electrically coupled to the second HVIL motor terminal; a second HVIL inverter terminal configured to electrically couple to a second sensing terminal; an inverter cover assembly, including: an inverter cover member configured to releasably couple to the housing of the electric drive unit; an inverter spring dip assembly, coupled to a surface of the inverter cover member, having inverter spring contacts that releasably engage the first HVIL inverter terminal and the second HVIL inverter terminal.

8. The cover system recited in claim 7, wherein: an HVIL drcuit exists in a first mode when the conductor physically and electrically engages the first ends, and the second ends physically and electrically engage the first HVIL motor terminal and the second HVIL motor terminal, and the spring terminals physically and electrically engage the first

HVIL inverter terminal and the second HVIL inverter terminal; and the HVIL drcuit exists in a second mode when the conductor is disengaged from the first HVIL motor terminal or the second HVIL motor terminal, or the spring contacts are disengaged from the first HVIL inverter terminal or the second HVIL motor terminal.

9. The cover system recited in claim 7, further comprising the electric drive unit and the housing.

10. The cover system redted in daim 7, wherein the spring contacts have a substantially C- or U-shape.

11. The cover system recited in claim 7, wherein the conductor is attached to the exterior cover member via an insulator.

12. The cover system redted in daim 7, wherein the exterior cover member couples to the housing via a plurality of fasteners to dose an opening in the housing.

13. The cover system recited in daim 7, wherein the electric motor assembly or the inverter motor assembly indudes an interference surface.

14. A cover system configured for use in an electric drive unit, comprising: a first high voltage interlock (HVIL) terminal electrically coupled to a first sensing terminal; a second HVIL terminal electrically coupled to a second sensing terminal; an exterior cover member, configured to releasably couple to a housing of the electric drive unit, including a conductor that faces a cavity of the housing; an intermediate cover member, including spring contacts that are at least partially encapsulated by the intermediate cover member, the spring contacts having first ends exposed on one side of the intermediate cover member and second ends exposed on an opposite side of the intermediate cover member, wherein the first ends are releasably biased into physical and electrical engagement with the conductor, the second ends are releasably biased into physical and electrical engagement with the first HVIL terminal or the second HVIL terminal; and a circuit board, including a sensing circuit having the first sensing terminal and the second sensing terminal, configured to determine whether an HVIL circuit exists in a first mode or a second mode.

15. The cover system recited in claim 14, wherein the cover system indudes an

HVIL circuit existing in a first mode when the conductor physically and electrically the first ends and the second ends engage the first HVIL terminal and the second

HVIL terminal or a second mode when the conductor physically and electrically disconnects from the first ends or the second ends disengage from the first HVIL terminal or the second HVIL terminal.