A POWER CUT-OFF MECHANISM

Abstract

The present subject matter relates to a rotating assembly (100) which comprises a rotating machine, a power converter, a housing (102) in which the rotating machine and the power converter are arranged. The power converter electrically interfaces with the rotating machine and forms an electronic circuit, the electrical interface being achieved by interconnecting a bus bar in the power converter and terminals of a stator in the rotating machine. The rotating assembly (100) further comprises an interface cover (104) which closes an interface opening, formed in the housing (102), the interface opening exposing the electrical interface. The rotating assembly (100) further comprises a power cut-off mechanism (106a; 106b) which comprises a cover-side device (106a) mounted on the interface cover (104), and a housing-side device (106b) mounted on the housing (102).The housing-side device (106b) is mounted on the housing (102) so as to maintain a threshold distance (dx) between the cover-side device (106a) and the housing-side device (106b). The threshold distance (dx) defines a predefined distance between the cover-side device (106a) and the housing-side device (106b) to trigger the closing of the electronic circuit. Figure for abstract: FIG. 1.

Description

Title of the invention: AN ELECTRICITY CUT-OFF MECHANISM FIELD OF THE INVENTION

[0001] The present subject matter generally relates to a power cut-off mechanism in a rotating assembly, and in particular to a power cut-off mechanism, provided on the housing of a rotating assembly, which provides safe opening and / or closing of an electronic circuit, housed in the housing, for maintenance. CONTEXT

[0002] Conventionally, an integrated motor system (or rotating assembly) includes a motor and an inverter electrically connected to the motor, and a housing in which the motor and inverter are housed. In operation, alternating current (AC) from the inverter is transmitted to the motor windings via an interface. The interface between the motor and inverter is achieved by interconnecting an inverter bus bar and the motor terminals. The interface is accessible for service through an interface opening in the housing that exposes the interface between the motor and inverter. An interface cover is used to close the interface opening in the housing. In high voltage motor applications, such openings in the housing can pose safety concerns for a person accessing the interface for service or repair.For example, in applications where the rotor assembly is used for traction of an electric vehicle, the high voltage current can electrocute the person accessing the interface. Therefore, for safety reasons, a power cut-off mechanism is used. In a known manner, a power cut-off switch is installed on the interface cover and is configured to stop the flow of current when the interface cover is opened during maintenance.

[0003] Conventionally, the power cut-off switch includes a male connector (usually with electrically conductive pins) that connects to a female connector installed on the housing. Therefore, when the interface cover closes the interface opening, the male connector is connected to the female connector and an electronic circuit of the rotor assembly is closed. When the interface cover is opened, the male connector and the female connector are disconnected from each other, thereby opening the electronic circuit of the rotor assembly and avoiding the risk of electrocution of maintenance personnel.

[0004] The above-described configuration of the conventional configuration of the power cut-off switch, i.e., the male connector and the female connector, however, is difficult to assemble. Specifically, mechanically aligning the male connector to the female connector when assembling the interface cover to the housing is difficult, as they must be precisely aligned. Misalignment during assembly can cause the pins in the male connector to bend or break, rendering the connector inoperative. Therefore, such misalignment results in parts replacement costs and wasted time. In addition, if one or both connectors are damaged, the electronic circuit remains open or closed. For example, in one scenario, damage to one or both connectors can leave the electronic circuit closed, even after removing the interface cover. In this case, the safety of maintenance personnel is at risk.In another scenario, damage to one or both connectors can leave the electronic circuit open, even after the interface cover is secured to the housing, rendering the rotating assembly inoperative.

[0005] Therefore, the technical problem to be solved by the present subject matter is to provide a power cut-off mechanism for opening and closing an electronic circuit of a rotating assembly for safe handling and maintenance, while ensuring that the structural integrity of the power cut-off mechanism is maintained. Summary of the invention

[0006] The present object aims to solve the above-mentioned technical problem of the power cut-off mechanism in a conventional rotating assembly. The present subject relates to a rotating assembly comprising: a rotating machine comprising a stator and a rotating rotor interacting with the stator; a power converter electrically interfacing with the rotating machine and forming an electronic circuit, the electrical interface being achieved by interconnecting a bus bar in the power converter and stator terminals in the rotating machine; a housing in which the rotating machine and the power converter are arranged, the housing comprising an interface opening that exposes the electrical interface; an interface cover attached to the housing and closing said interface opening;a power cut-off mechanism comprising a cover-side device mounted on the interface cover, and a housing-side device mounted on the housing, wherein a threshold distance is maintained between the cover-side device and the housing-side device, the threshold distance defining a predefined distance between the cover-side device and the housing-side device to trigger closure of the electronic circuit.;

[0007] The power disconnect mechanism requires no direct mechanical interaction and is therefore not susceptible to structural damage. In addition, opening and closing the electronic circuit by separating and securing the interface cover provides an automated means of ensuring the safety of maintenance personnel accessing the electrical interface. In addition, the power disconnect mechanism allows real-time monitoring of whether the interface cover is secured or removed from the housing. The threshold distance is maintained between the cover-side device and the housing-side device when the interface cover is secured to the housing. This threshold distance indicates that the interface cover is secured to the housing.If, in the scenario where the interface cover is separated, a distance between the cover side device and the housing side device exceeds the threshold distance, the electronic circuit is open.

[0008] According to another example of the present subject matter, the housing comprises: a first portion for housing the rotating machine, a second portion for housing the power converter, and a third portion for housing the electrical interface between the rotating machine and the power converter. The third portion, also known as the "terminal box," accommodates the phase cables, among other internal components, that connect the stator of the rotating machine and the bus bar of the power converter. The interface opening is formed specifically on the third portion of the housing, and the interface cover is adapted to cover this third portion. The interface cover can facilitate the sealing of the interface opening when attached.

[0009] According to one aspect of the present subject matter, the housing-side device is mounted in the third portion where the electrical interface is housed and is exposed through the interface opening when the interface cover is separated from the housing.

[0010] According to one aspect of the present subject matter, the cover side device is mounted on one side of the inner surface of the interface cover.

[0011] According to one aspect of the present subject matter, the side device of the cover faces the side device of the housing when the interface cover is attached to the housing.

[0012] According to an example of the present subject matter, the housing-side device is a sensor and the cover-side device is a target detectable by the sensor when the interface cover is attached to the housing. Accordingly, if the threshold distance is reached, the electronic circuit is closed and the rotating assembly can operate.

[0013] According to an example of the present subject matter, the sensor is a proximity sensor and the target is a metal target, the proximity sensor being adapted to detect the threshold distance. The proximity sensor may be a capacitive proximity sensor, an inductive proximity sensor, a photoelectric sensor, a magnetic proximity sensor or an ultrasonic proximity sensor. Depending on the types of sensors proximity targets mentioned above, a suitable target, metallic or non-metallic, is selected.

[0014] According to an example of the present subject, the housing comprises a transmission portion in which a gear system is arranged, the gear system being coupled to a rotor shaft of the rotating machine. The aforementioned configuration of the rotating housing with the rotating machine, the power converter and the gear system included in a single housing is called "eAxle". Such an axle can provide traction for an at least partially electric motor vehicle by means of a coupling between the gear system and an axle.

[0015] The present subject matter also relates to a method for controlling an electronic circuit of a rotating assembly configured in the manner described above, the method comprising: detecting a distance between the cover-side device and the housing-side device; closing the electronic circuit in response to the distance equal to the threshold distance between the cover-side device and the housing-side device, said threshold distance indicating attachment of the interface cover to the housing; and opening the electronic circuit when the distance between the cover-side device and the housing-side device exceeds the threshold distance. In one example, the housing-side device is the sensor and the cover-side device is the target. In another example, the cover-side device is the sensor and the housing-side device is the target. In both of the aforementioned examples, the sensor continuously monitors the proximity of the target.When the target is at or below the threshold distance dx from the sensor, the sensor sends a signal to a control unit, which causes the electronic circuit to close. When the target is at a distance greater than the threshold distance dx from the sensor, the sensor sends a signal to the control unit, which triggers the electronic circuit to open. As a result, automated and safe switching on and off of the electronic circuit is achieved by the housing-side device and the cover-side device of the power cut-off mechanism. In addition, the power cut-off mechanism allows real-time control depending on whether the interface cover is attached to or removed from the housing. There is no direct mechanical interaction or contact between the housing-side device and the cover-side device during operation, thus preventing structural damage. Brief description of the drawings

[0016] The features, aspects and advantages of the present invention will be better understood in light of the following description and the accompanying figures. The description refers to the accompanying drawings, in which:

[0017] [Fig.l] illustrates a schematic view of a rotating assembly, in particular a schematic view of a housing of the rotating assembly and an interface cover of the rotating assembly, configured in accordance with the present subject matter;

[0018] [Fig.2] illustrates a rotating electrical machine, representing a region 114, configured in accordance with the present subject matter;

[0019] [Fig. 3] illustrates a zoomed perspective view of region 114 of the rotating machine shown in [Fig. 2], configured in accordance with the present subject matter; and

[0020] [Fig.4] is a schematic view of the rotating assembly for providing traction to an axle of a motor vehicle, configured in accordance with an example of the present subject matter.

[0021] The figures are not necessarily to scale and the size of certain parts may be exaggerated to more clearly illustrate the example shown. In addition, the drawings provide examples and / or examples consistent with the description, but the description is not limited to the examples and / or examples provided in the drawings. DETAILED DESCRIPTION

[0022] In the following description, reference is made to the accompanying drawings, which are an integral part of the invention, and in which are illustrated specific embodiments in which the invention may be embodied. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that the embodiments may be combined, or that other embodiments may be used, and that structural and logical modifications may be made without departing from the scope of the present invention. The detailed description which follows is therefore not to be construed in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0023] [Fig. 1] illustrates a schematic view of a rotating assembly 100, configured in accordance with the present subject matter. [Fig. 2] illustrates a perspective view of the rotating assembly 100, configured in accordance with the present subject matter. [Fig. 3] illustrates a zoomed view of [Fig. 2], particularly illustrating a region 114 of the rotating assembly 100 configured in accordance with the present subject matter.

[0024] The present subject matter relates to a rotating assembly 100 which comprises a rotating machine 110, a power converter 112 electrically interfacing with the rotating machine 110, a housing 102 in which the rotating machine 110 and the power converter 112 are housed, an interface cover 104 for closing an interface opening 122 formed on the housing 102, and a power cut-off mechanism 106a, 106b. The rotating machine 110 comprises a stator 118 and a rotor rotatable in interaction with the stator 118. An electronic circuit is formed by virtue of the electrical interface between the power converter 112 and the rotating machine 110. The electrical interface is achieved by interconnecting a bus bar 116 in the power converter 112 and stator terminals 118 in the rotating machine 110. The power cut-off mechanism 106a, 106b comprises a cover-side device 106a and a housing-side device 106b. The cover-side device 106a is mounted on the interface cover 104; and the housing-side device 106b is mounted on the housing 102. The cover-side device 106a and the housing-side device 106b are configured to interact with each other to close the electronic circuit when the interface cover 104 is attached to the housing 102. Further, when the interface cover 104 is separated from the housing 102, the interaction between the cover-side device 106a and the housing-side device 106b is configured to open the electronic circuit.

[0025] According to the present subject matter, the rotating machine 110 operates to convert electrical energy into mechanical energy, or vice versa. The power converter 112 converts direct current (DC) into alternating current (AC), or vice versa. Therefore, the power converter 112 may operate as a bridge rectifier in generator mode and / or as an inverter in motor mode of the rotating machine 110. The housing 102 houses both the rotating machine 110 and the power converter 112. Detachment of the interface cover 104 reveals the interface opening 122 in a region 114 (a zoomed perspective of which is shown in [Fig. 3]) where the interconnection between the bus bar 116 of the power converter 112 and the terminals of the stator 118 is accessible. The interface cover 104 protects the internal components, particularly the electrical interface, from external damage.It is therefore desirable that the interface cover 104 hermetically seals the interface opening 122 where the electrical interface is exposed. The interface cover 104 is secured to the housing 102 by means of fasteners (not shown).

[0026] In the assembled state, when the interface cover 104 is attached to the housing 102, the housing-side device 106b detects the presence of the cover-side device 106a in close proximity and thus facilitates the closing of the electronic circuit. Direct mechanical contact between the housing-side device 106b and the cover-side device 106a is established in the assembled state. Furthermore, in the assembled state, a threshold distance dx is maintained between the cover-side device 106a and the housing-side device 106b. In a scenario where the electrical interface needs to be serviced, the fasteners are removed and the interface cover 104 is detached. As a result, the cover-side device 106a is further away from the housing-side device 106b. Furthermore, the increase in the distance between the cover-side device 106b and the housing-side device 106b is detected by the housing-side device 106b, and the mechanism of power cut-off 106a, 106b facilitates the closing of the electronic circuit. Therefore, in the disassembled state, when the interface cover 104 is separated from the housing 102, the current flow in the electronic circuit is cut off and the rotating assembly 100 does not operate. Personnel can therefore access the electrical interface without fear of being electrocuted.

[0027] In the example illustrated in [Fig. 2] and 3, the housing 102 is formed of several parts. A first part for housing the rotating machine 110, a second part for housing the power converter 112, and a third part (commonly referred to as a "terminal box") for housing the electrical interface. The third part is what is shown in [Fig. 2] and 3 as the region 114 where the interface opening 122 is formed. [Fig. 3] focuses on the region 114 and more particularly on the interface opening 122 which exposes the internal components. One of these exposed internal components is the phase cable 120 that connects the terminals of the stator 118 (specifically, the terminals of the end windings 117 of the stator 118) and the bus bar 116 in the power converter 112. The housing-side device 106b may be one of the internal components exposed upon separation and removal of the interface cover 104.In other words, the housing-side device 106b is disposed in the third portion of the housing 102 and is oriented to face the cover-side device 106a when the interface cover 104 is attached to the housing 102.

[0028] According to the present object, the housing-side device 106b is mounted inside the third part, i.e., in the housing 102 where the interface opening 122 is formed. The cover-side device 106b is mounted on an inner surface 108 of the interface cover 104. When assembling the interface cover 104 to the housing 102, the interface cover 104 is moved in an assembly direction 108, illustrated in [Fig. 1], and fixed so that the cover-side device 106a and the housing-side device 106b are aligned along a direction parallel to the assembly direction 108. The assembly direction 108 is a direction parallel to a rotation axis 124 of the rotor, the rotation axis 124 being directed toward [Fig. 2] as shown.

[0029] According to one example of the present subject matter, the housing-side device 106b is a sensor and the cover-side device 106a is a target. The target is detectable by the sensor when the interface cover 104 is attached to the housing 102. In another example, the cover-side device 106a is a sensor and the housing-side device 106b is a target detectable by the sensor when the interface cover 104 is attached to the housing 102. In both of the aforementioned examples, the sensor and the target are configured to be aligned parallel to the assembly direction 108 once the interface cover 104 is attached to the housing 102. Furthermore, the sensor and the target are configured to face each other in the assembled state. In the assembled state, a threshold distance dx is maintained between the target and the sensor. In other words, no direct mechanical contact is made between the sensor and the target. This threshold distance dx between the target and the sensor is controlled by the sensor and the electronic circuit is opened or closed accordingly. In both of the aforementioned examples, the sensor continuously monitors the proximity of the target. When the target is at or below the threshold distance dx from the sensor, the sensor sends a signal to a control unit (not shown), causing the electronic circuit to close. In the event that the interface cover 104 is separated from the housing 102, the threshold distance dx increases, indicating that the interface cover 104 is separated. A signal indicating the separation of the interface cover 104 facilitates instantaneous opening of the electronic circuit.In the case where the interface cover 104 is assembled or fixed to the housing 102, the distance between the cover-side device 106a and the housing-side device 106b exceeds the threshold distance dx; consequently, the signal indicating the fixing of the interface cover 104 facilitates the instantaneous closing of the electronic circuit. Accordingly, the power cut-off mechanism 106a, 106b enables the electronic circuit to be activated and deactivated in an automated and safe manner.

[0030] According to an example of the present subject, the sensor is a proximity sensor suitable for detecting the threshold distance dx. Accordingly, a suitable target can be chosen. Furthermore, the proximity sensor can be one of the following types: capacitive proximity sensor, inductive proximity sensor, photoelectric sensor, magnetic proximity sensor or ultrasonic proximity sensor. Preferably, the proximity sensor is an inductive proximity sensor and, therefore, the target is a metal target. Therefore, in the example where the housing-side device 106b is a sensor and the cover-side device is a target 106a, the sensor can be an inductive sensor and the target can be a metal target. The operating principle of inductive proximity sensors is generally known and is therefore not developed in the present description.Therefore, once the interface cover 104 is attached to the housing 102, the inductive sensor (located in the housing 102, in the region 114) detects the threshold distance dx of the metal target (located on the inner surface 108 of the interface cover 104) and closes the electronic circuit of the rotating assembly 100.

[0031] According to an example of the present subject, the housing 102 of the rotating assembly 100 further comprises a transmission portion where a gear system 126 is arranged. Such a rotating assembly 100 of the aforementioned type, which comprises the rotating machine 110, the power converter 112 and the gear system 126 in a single housing 102, is commonly referred to as an "eAxle". The gear system 126 of the rotating assembly 100 (configured in the "eAxle" type) is coupled to the rotating machine 110. The coupling is achieved by coupling a rotor shaft (not shown) in the rotor of the rotating machine 110 and a gear in the gear system 126. Furthermore, as shown in [Fig. 2], the gear system 126 is disposed between the rotating machine 110 and the power converter 112, the power converter 112 being disposed and / or aligned in a direction tangential to the axis of rotation 124 of the rotating machine 110. The third part of the housing 102 is provided at the region 114 for accommodating the electrical interface between the rotating machine 110 and the power converter 112.

[0032] [Fig. 4] illustrates a schematic view of the eAxle type rotating assembly 100, an example of which is also illustrated in [Fig. 3]. A power source 400, such as a battery, provides direct current to the power converter 112. The power converter 112, operating as an inverter in motor mode and as a rectifier in generator mode, provides power to the rotating machine 110. For example, in motor mode, the power converter 112 provides alternating current to the rotating machine 110. The alternating current is provided to the stator 118 of the rotating machine 110 by an electrical interface 402, i.e., the phase cables 120, shown in the region 114 where the third part (terminal box) of the housing 102 is provided. The rotor shaft of the rotating machine 110 is coupled to the gear system 126 for torque transfer between the two.Furthermore, the gear system is coupled to an axle 404 of a motor vehicle (the motor vehicle being at least partially electric), thereby providing traction to the motor vehicle. The aforementioned normal operation of the rotating assembly 100 is ensured if the electronic circuit is closed. The electronic circuit is only closed if the power cut-off mechanism 106a, 106b indicates that the interface cover 104 is secured to the housing 102.

[0033] In the scenario where intervention is required, particularly if intervention at the electrical interface is required, the interface cover 104 is removed to reveal the interface opening 122, as shown in [Fig. 2] and 3. The power shutoff mechanism 106a, 106b, in this scenario, detects that the distance between the sensor and the target exceeds the threshold distance dx; and accordingly closes the electronic circuit of the rotating assembly 100, thereby allowing maintenance personnel to access the electrical interface 402 to perform repairs without exposing themselves to safety issues, such as electrocution.

[0034] [Fig.5] illustrates a flowchart representing a method 500 for controlling an electronic circuit of a rotating assembly 100 configured in accordance with the present subject matter. According to the present subject matter, the method 500 comprises a step 502 of detecting a distance between the cover-side device 106a and the housing-side device 106b. In the example where the housing-side device 106b is the sensor and the housing-side device cover 106a is the target, the sensor continuously monitors the proximity of the target. In another example, the cover-side device 106a is the sensor and the housing-side device 106b is the target, and the sensor continuously monitors the proximity of the target from the sensor.

[0035] Furthermore, the method 500 comprises a step 504 of closing the electronic circuit in response to the distance equal to the threshold distance dx between the cover-side device 106a and the housing-side device 106b. The threshold distance dx indicates an attachment of the interference cover 104 to the housing 102. The method 500 further comprises a step 506 of opening the electronic circuit when the distance between the side device 106a and the side device 106b exceeds the threshold distance dx. In the case where the target is at a distance equal to or less than the threshold distance dx with respect to the sensor, the sensor sends a signal to the control unit which triggers the closing of the electronic circuit. The closing of the electronic circuit is carried out without direct mechanical contact between the sensor and the target.

[0036] The method 500 further comprises a step 506 of opening the electronic circuit when the distance between the cover-side device 106a and the housing-side device exceeds the threshold distance dx. Consequently, in the case where the target is at a distance greater than the threshold distance dx relative to the sensor, the latter sends a signal to the control unit which triggers the opening of the electronic circuit. The opening of the electronic circuit is done without direct mechanical contact between the sensor and the target.

[0037] Various modifications to the disclosed embodiments, as well as other embodiments of the subject matter, will become apparent to those skilled in the art upon reference to the description of the subject matter. It is therefore contemplated that such modifications may be made without departing from the scope of the present subject matter.

Claims

Claims

1. A rotating assembly (100) comprising: a rotating machine (110) including a stator (118) and a rotor rotatable in interaction with the stator (118); a power converter (112) electrically interfacing with the rotating machine (110) and forming an electronic circuit, the electrical interface being provided by interconnecting a bus bar (116) in the power converter (112) and terminals of the stator (118) in the rotating machine (110); a housing (102) in which the rotating machine (110) and the power converter (112) are disposed, the housing (102) including an interface opening (122) that exposes the electrical interface (402); an interface cover (104) attached to the housing (102) and closing said interface opening (122); a power cut-off mechanism (106a;106b) comprising a cover-side device (106a) mounted on the interface cover (104), and a housing-side device (106b) mounted on the housing (102), wherein a threshold distance (dx) is maintained between the cover-side device (106a) and the housing-side device (106b), the threshold distance (dx) defining a predefined distance between the cover-side device (106a) and the housing-side device (106b) for triggering the closing of the electronic circuit.;

2. The rotating assembly (100) of claim 1, wherein the housing (102) comprises: a first portion for housing the rotating machine (110), a second portion for housing the power converter (112), and a third portion for housing the electrical interface (402) between the rotating machine (110) and the power converter (112).

3. A rotating assembly (100) according to claim 2, wherein the housing-side device (106a) is mounted in the third portion where the electrical interface (402) is housed and is exposed through the interface opening (122) when the interface cover (104) is separated from the housing (102).

4. A rotary assembly (100) according to any preceding claim, wherein the cover-side device (106a) is mounted on an inner face 108 of the interface cover (104).

5. A rotary assembly (100) according to any preceding claim, wherein the cover side device (106a) faces the housing side device (106b) when the interface cover (104) is attached to the housing (102).

6. A rotating assembly (100) according to any preceding claim, wherein the housing-side device (106b) is a sensor and the cover-side device (106a) is a target detectable by the sensor when the interface cover (104) is attached to the housing (102).

7. A rotating assembly (100) according to one of claims 1 to 5, wherein the cover-side device (106a) is a sensor and the housing-side device (106b) is a target detectable by the sensor when the interface cover (104) is attached to the housing (102).

8. A rotating assembly (100) according to any preceding claim, wherein the sensor is a proximity sensor and the target is a metal target, the proximity sensor being adapted to detect the threshold distance (dx).

9. A rotating assembly (100) according to any preceding claim, wherein the housing (102) comprises a transmission portion in which a gear system (126) is disposed, the gear system (126) being coupled to a rotor shaft of the rotating machine (110).

10. A method (500) of controlling an electronic circuit of a rotating assembly (100) configured according to any preceding claim, the method (500) comprising: detecting a distance between the cover side device (106a) and the housing side device (106b); closing the electronic circuit in response to the distance equal to the threshold distance (dx) between the cover side device (106a) and the housing side device (106b), said threshold distance (dx) indicating attachment of the interface cover (104) to the housing (102); and opening the electronic circuit when the distance between the cover side device (106a) and the housing side device (106b) exceeds the threshold distance (dx).

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