Electrical discharge arrangement for an electric machine and method for manufacturing an electrical discharge arrangement for an electric machine

Abstract

Current discharge arrangement (1000, 1100) for an electric machine in an electric vehicle, wherein the current discharge arrangement (1000, 1100) comprises: a rotor shaft (104) that defines an outer diameter of a channel (106); a mass element (108) positioned in the channel (106), wherein the mass element (108) is a tube (1008) extending into the channel (106) of the rotor shaft (104) and configured to supply a lubricant into the channel (106) of the rotor shaft (104); and a connector (200, 600) positioned in the channel (106) of the rotor shaft (104) and extending circumferentially between the rotor shaft (104) and the mass element (108), wherein the connector (200, 600) is configured to electrically couple the rotor shaft (104) to the mass element (108) when the rotor shaft (104) rotates, in order to allow current to flow from the rotor shaft (104) to the mass element (108) via the connector (200, 600); characterized by the fact that the current discharge arrangement (1000, 1100) further comprises a first and a second plug (1030, 1040) positioned in the channel (106) between the tube (1008) and the rotor shaft (104), the plugs (1030, 1040) being configured to prevent the lubricant supplied through the tube (1008) from touching the connector (200, 600), the first plug (1030) being positioned adjacent to a first side of the connector (200, 600) and the second plug (1040) being positioned adjacent to a second side of the connector (200, 600) opposite the first side; wherein the current discharge arrangement (1000, 1100) further includes a mounting bracket (1020) which runs circumferentially along the outer diameter of the channel (106) and to which the connector (200, 600) and the two plugs (1030, 1040) are attached.

Description

INTRODUCTION

[0001] The present invention relates to bearing current discharge arrangements for an electric vehicle and in particular to a current discharge arrangement for an electric machine as well as to a method for manufacturing a current discharge arrangement for an electric machine.

[0002] A generic current discharge arrangement for an electric machine is essentially described in DE 10 2021 213 387 A1. Further prior art is described in EP 4 068 581 A2 and DE 10 2016 010 926 A1.

[0003] An electric vehicle (EV) contains one or more electric machines that function as a motor to propel the vehicle forward and as a generator during regeneration. The electric machines comprise an EV drive unit, which includes a stator, main bearings, a rotor shaft that rotates in the main bearings, and a rotor mounted on the rotor shaft that rotates relative to the stator. Sometimes, a current is generated in the rotor shaft due to a voltage differential created across the shaft based on a magnetic field generated between the stator and the rotor. This current is often referred to as electrical discharge current (EDM current). The current can circulate from the rotor shaft and cause damage to the main bearings.To reduce this circulating current, some electric machines may employ a brush, carbon rods, or a sacrificial bearing positioned on the outside of the rotor shaft. SUMMARY

[0004] According to the invention, a current discharge arrangement for an electrical machine is presented, characterized by the features of claim 1.

[0005] According to further characteristics, the connector is a brush that contains a body and several bristles extending from the body.

[0006] According to further characteristics, the multiple bristles contain carbon fiber.

[0007] According to further characteristics, the multiple bristles run from the body to the mass element and are configured to touch the mass element.

[0008] According to further characteristics, the multiple bristles run from the body to the rotor shaft and are configured to touch the rotor shaft.

[0009] According to further characteristics, the connector is a bearing that is positioned between the rotor shaft and the mass element.

[0010] According to further characteristics, the bearing is either a rolling bearing or a ball bearing.

[0011] According to further features, the connector contains a body and one or more spring-loaded rods configured to preload against one or more of the rotor shaft and the mass element.

[0012] According to further characteristics, one or more spring-loaded rods are configured to be preloaded against the rotor shaft.

[0013] According to further characteristics, one or more spring-loaded rods are configured to be preloaded against the mass element.

[0014] Furthermore, according to the invention, a method for manufacturing a current discharge arrangement for an electric machine in an electric vehicle is presented, which is characterized by the features of claim 5.

[0015] The electric machine includes a rotor shaft that defines a shaft channel. The method comprises providing a mounting bracket having a body defining a mounting bracket channel through it, cutting at least one recess in the body of the mounting bracket, attaching a connector to the mounting bracket by means of the recess, the connector extending into the mounting bracket channel, inserting a ground element into the mounting bracket channel of the mounting bracket such that it contacts the connector extending into the mounting bracket channel, and inserting the ground element and the mounting bracket with the attached connector into the shaft channel of the rotor shaft such that the connector electrically couples the rotor shaft to the ground element when the rotor shaft rotates, allowing current to flow from the rotor shaft to the ground element via the connector.

[0016] According to further characteristics, attaching the connector to the mounting bracket by means of the recess involves pressing the connector into the recess.

[0017] According to further characteristics, the connector is a brush that has several bristles.

[0018] According to further characteristics, the mass element is a tube configured to deliver a lubricant into the shaft channel of the rotor shaft.

[0019] According to further features, the method also includes forming at least one plug between the tube and the rotor shaft to prevent the lubricant supplied through the tube from touching the brush.

[0020] Further applications of the present invention will become apparent from the detailed description, the claims, and the drawings. The detailed description and the specific examples serve only for illustration. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be more fully understood from the detailed description and the accompanying drawings; these show: Fig. 1 a diagram of an exemplary current discharge arrangement for an electric machine in an electric vehicle according to the present invention; Fig. 2-3 diagrams of example brushes used in the current discharge arrangement of Fig. 1 are usable according to the present invention; Fig. 4-5 Diagrams of exemplary spring-loaded connectors used in the current discharge arrangement of Fig. 1 are usable according to the present invention; Fig. 6 a diagram of an example bearing used in the current discharge arrangement of Fig. 1 can be used according to the present invention; Fig. 7 A diagram of an example connector and an internal mounting bracket used in the current discharge arrangement of Fig. 1 can be used according to the present invention; Fig. 8 a diagram of the inner mounting bracket of Fig. 7; Fig. 9 a diagram of another example bearing, which is used in the current discharge arrangement of Fig. 1 can be used according to the present invention; Fig. 10 a diagram of another exemplary current discharge arrangement, which includes the brush of Fig. 2 contains, according to the present invention; Fig. 11 a diagram of another exemplary current discharge arrangement, which the bearing of Fig. 6 contains, according to the present invention and Fig. 12 a diagram of an exemplary method for producing a current discharge arrangement according to the present invention.

[0022] Reference symbols can be used multiple times in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0023] An electric vehicle (EV) contains one or more electric machines that have an EV drive unit. In such examples, the EV drive unit includes a stator, main bearings, a rotor shaft rotating in the main bearings, and a rotor mounted on the rotor shaft and rotating relative to the stator. Within the EV drive unit, circulating current, such as an EDM current generated in the rotor shaft, can pass through the main bearings, causing bearing damage. This, in turn, can lead to severe noise, vibration, and harshness (NVH) problems and even system failure. Current-reducing devices are positioned on the outside of the rotor shaft. However, due to their size, such devices require additional assembly space and are often ineffective in lubricated environments.

[0024] The current discharge arrangements according to the present invention provide solutions for positioning a connector, such as a brush, bearing, etc., in a rotor shaft and around a mass element, such as a lubrication tube, within the rotor shaft. With this configuration, the connector electrically couples an inner surface of the rotor shaft and an outer surface of the mass element, which is located in a central region of the rotor shaft, when, for example, the rotor shaft rotates. Circulating current (e.g., EDM current, etc.) generated in the rotor shaft is discharged to the mass element via the connector. Due to the low linear velocity at the center of the rotor shaft, the mass element presents low resistance and an efficient path for current discharge with a low risk of degradation.Additionally, because the connector is positioned in the rotor shaft, the assembly space around the outside of the rotor shaft can be reduced compared to conventional systems or used for other purposes.

[0025] Now, with reference to Fig. Figure 1 shows an exemplary current discharge arrangement 100 for an electric machine in an EV. In such examples, the EV can be a pure EV, a hybrid vehicle, a fuel cell vehicle, or any other suitable type of EV having one or more electric machines that operate as a motor to propel the vehicle forward and as a generator during regeneration.

[0026] As shown, the current discharge arrangement 100 generally includes a bearing 102, a rotor shaft 104 rotating on the bearing 102, a mass element 108 in the rotor shaft 104, and a connector 110 in the rotor shaft 104. While it is in Fig. Not shown in Figure 1, the current discharge arrangement 100 can be used with other conventional components of the electric machine of the EV, such as a stator (which is connected, for example, to a housing of the electric machine), a rotor which is mounted on the rotor shaft 104 and rotates in relation to the stator.

[0027] In the example of Fig. Figure 1 defines a channel 106 on the rotor shaft 104. For example, the rotor shaft 104 can be a tubular structure. In such examples, the rotor shaft 104 contains an inner surface 112 that defines the channel 106, as shown in Figure 1. Fig. Figure 1 is shown. With this configuration, the inner surface 112 of the rotor shaft 104 defines an outer diameter of the channel 106.

[0028] As in Fig. As shown in Figure 1, the grounding element 108 is an electrically conductive and grounded device. In various embodiments, the grounding element 108 can be made of or contain electrically conductive material such as steel, copper, aluminum, carbon, etc. In the example of Fig. 1. The mass element 108 can be grounded in any suitable manner. For example, an outer surface 116 of the mass element 108 can be directly coupled to a ground (e.g., an earth mass). In other examples, the outer surface 116 of the mass element 108 can be indirectly coupled to ground by means of another electrically conductive component, such as a grounded metal retaining bracket that touches the mass element 108.

[0029] The mass element 108 is positioned in the channel 106, which is defined by the rotor shaft 104. In particular, in the example of Fig. 1. The mass element 108 is located in the channel 106 of the rotor shaft 104. In various embodiments, the mass element 108 can be a lubrication tube extending from a lubricant source to the channel 106. In such examples, the lubrication tube can supply a lubricant to the channel 106 of the rotor shaft 104. Such a lubricant flow is represented by an arrow 114, which has a dash-dot-dash configuration. In further examples, the mass element 108 can be another suitable device that is electrically conductive and grounded.

[0030] In various embodiments, the current discharge arrangement 100 may include one or more further optional components. For example, and as further explained below, the current discharge arrangement 100 may include one or more plugs (not shown) positioned on one or both sides of the connector 110. In such examples, the one or more plugs may be positioned in the channel 106 between the mass element 108 (e.g., the tube) and the rotor shaft 104. In various embodiments, if the mass element 108 is a lubrication tube, part of the plugs may act as a seal to prevent lubricant supplied through the tube from contacting the connector 110.

[0031] Additionally, in certain examples, the current discharge assembly 100 may include an electrically conductive mounting bracket or retaining ring (not shown), as further explained below. In such examples, various components, such as the connector 110, one or more plugs, etc., may be attached to the mounting bracket by means of adhesive, solder, one or more mechanical fasteners (e.g., screws, rivets, etc.), and / or other suitable fasteners. With this configuration, the mounting bracket can provide a mechanism for holding components of the current discharge assembly 100 in one piece. Again, this can provide ease of installation and / or removal of components of the current discharge assembly 100 during the manufacture and / or maintenance of the electrical machine (e.g., the EV drive unit).

[0032] As in Fig. As shown in Figure 1, the connector 110 is an electrically conductive device positioned in the channel 106 of the rotor shaft 104. Specifically, the connector 110 runs circumferentially between the rotor shaft 104 and the mass element 108, as shown in Figure 1. Fig. Figure 1 is shown. In various embodiments, the connector 110 can be made of or contain electrically conductive material such as steel, copper, aluminum, carbon, conductive grease, etc.

[0033] In the example of Fig. 1. Connector 110 electrically couples the rotor shaft 104 to the ground element 108. This can occur when the rotor shaft 104 is rotating, and sometimes when the rotor shaft 104 is not rotating. This configuration allows EDM current, generated in the rotor shaft 104 due to an accumulated voltage on the rotor shaft 104 and / or other circulating current in the rotor shaft 104, to flow from the rotor shaft 104 to the ground element 108 via connector 110. Therefore, current is diverted away from the bearing 102, thus preventing damage to the bearing 102. In the example of Fig. 1 The current flow is represented by an arrow 118, which has a double-dashed configuration.

[0034] In the example of Fig. 1. The connector 110 can be any suitable type of device that provides an electrically conductive path between the rotor shaft 104 and the ground element 108 for the flow of current. In various embodiments, the connector 110 can be structured to accommodate the movement (e.g., rotation) of the rotor shaft 104 with respect to the stationary ground element 108. For example, and as further explained here, the connector 110 can include a brush, a bearing (e.g., a sacrificial bearing), one or more spring-loaded rods, etc.

[0035] For example, they Fig. 2- Fig. Three examples of different configurations of brushes 200, 300 are shown, which are used as the connector 110 of Fig. 1 can be used. For example, and as in Fig. 2- Fig. As shown in Figure 3, each brush is 200, 300 in channel 106 of rotor shaft 104. Fig. 1 and between the inner surface 112 of the rotor shaft 104 and the outer surface 116 of the mass element 108 of Fig. Positioned 1.

[0036] Specifically, Fig. 2. The brush 200 is described as comprising a body 202 and bristles 204 extending from the body 202. In such examples, the body 202 and the bristles 204 may be made of or contain any suitable electrically conductive material. For example, the body 202 may be made of or contain steel, aluminum, copper, etc. Additionally, the bristles 204 may contain carbon fiber or another suitable conformal conductive material.

[0037] For example, Fig. 2. The brush 200 has a single-brush configuration. For example, and as shown in Fig. As shown in Figure 2, the bristles 204 extend from the body 202 to the mass element 108 (e.g., the tube) and touch the outer surface 116 of the mass element 108. In such examples, the body 202 of the brush 200 can be attached to the inner surface 112 of the rotor shaft 104 (e.g., glued, soldered, mechanically fastened, etc.), as shown in Figure 2. Fig. Figure 2 is shown. Alternatively, in other embodiments, the body 202 can be attached to a mounting bracket when it is used.

[0038] In Fig. 3 is the brush 300 similar to the brush 200 from Fig. 2, however, brush 300 is in a different configuration. Specifically, brush 300 contains the body 202 and the bristles 204 of Fig. 2, however, brush 300 has a brushing configuration. For example, and as shown in Fig. As shown in Figure 3, the bristles 204 extend from the body 202 to the rotor shaft 104 and touch the inner surface 112 of the rotor shaft 104. In such examples, the body 202 of the brush 300 can be attached to the outer surface 116 of the mass element 108 (e.g., glued, soldered, mechanically fastened, etc.).

[0039] In the examples of Fig. 2- Fig. 3. The bristles 204 can extend from the body 202 in any suitable manner. For example, the bristles 204 can cover all or part of the outer circumference of the body 202. In such examples, the bristles 204 can extend from Fig. 2 completely or partially enclose the corresponding section of the outer surface 116 of the mass element 108 and can extend the bristles 204 from Fig. 3 completely or partially enclose the corresponding section of the inner surface 112 of the rotor shaft 104. In addition, in certain examples, the bristles 204 of Fig. 2- Fig. 3. extend uniformly from the body 202 or not. For example, the bristles 204 can form a uniform block, a helix, etc. In other examples, the bristles 204 can be arranged in the inner or outer section of the body 202 (e.g., a brush ring base).

[0040] Additionally, the brushes can be 200, 300 of Fig. 2- Fig. 3. The brushes may be of any suitable size. For example, the brushes 200, 300 may have a suitable width and a relatively thin ring to fit between the inner diameter of the rotor shaft 104 and around the outer surface 116 of the mass element 108. In various embodiments, the brushes 200, 300 may have a wide base and a thin ring shape to fit within a radius space in the range of about 5 mm to about 10 mm with an inclination of less than about 15 mm. In certain examples, the bristle path of the bristles 204 may be longer than that of conventional brushes and / or the brushes 200, 300 may contain a stack of several narrow brush rings.

[0041] Fig. 4- Fig. Figure 5 represents examples of different configurations of spring-loaded connectors 400, 500, which are known as connector 110 from Fig. 1 can be used. For example, and as in Fig. 4- Fig. As shown in Figure 5, each connector 400, 500 is between the inner surface 112 of the rotor shaft 104 and the outer surface 116 of the mass element 108. Fig. Positioned 1.

[0042] Specifically, Fig. 4. The connector 400 is represented as a body 402 and two spring-loaded rods 404 extending from the body 402. In such examples, the body 402 is a circular structure that can contact the inner surface 112 of the rotor shaft 104. In the example of Fig. 4 Each spring-loaded rod 404 contains a housing 406 attached to the body 402 and an elongated element 408 projecting from the housing 406.

[0043] In the example of Fig. 4. The spring-loaded rods 404 preload against the outer surface 116 of the mass element 108. For example, although not shown, each spring-loaded rod 404 contains a preloading element (e.g., a spring, etc.) to press the elongated element 408 inwards and against the mass element 108.

[0044] In Fig. 5 is the connector 500 similar to the connector 400 from Fig. 4, however, connector 500 is in a different configuration. Specifically, connector 500 contains the body 402 and two spring-loaded rods 404. Fig. 4. However, it touches on Fig. 5 of the body 402 the outer surface 116 of the mass element 108. In addition, the spring-loaded rods 404 of Fig. 5 against the inner surface 112 of the rotor shaft 104. For example, the preload element (which is in Fig. (5 not shown) of each spring-loaded rod 404 the elongated element 408 outwards and towards the rotor shaft 104.

[0045] The spring-loaded rods 404 from Fig. 4- Fig. 5 can comprise any suitable electrically conductive material. For example, the spring-loaded rod 404 can contain a carbon rod (e.g., carbon graphite) as the elongated element 408. Additionally, while the connectors 400, 500 of Fig. 4- Fig. 5, which are shown as containing two spring-loaded rods 404, it should be acknowledged that in further embodiments more or fewer spring-loaded rods can be used if desired.

[0046] Fig. Figure 6 represents an example of a bearing 600, which is used as the connector 110 of Fig. 1 can be used. For example, and as in Fig. As shown in Figure 6, bearing 600 is located in channel 106 of rotor shaft 104. Fig. 1 and between the inner surface 112 of the rotor shaft 104 and the outer surface 116 of the mass element 108 of Fig. 1 positioned. In such examples, camp 600 can be a sacrificial camp.

[0047] Especially in Fig. 6. Bearing 600 is an example of a rolling bearing. In such examples, the bearing 600 can include conventional components such as an outer race 602 that rotates with the rotor shaft 104, a cage 606 for holding rolling elements, and an inner race 610. Additionally, in certain examples, the bearing 600 can include a seal (e.g., a solid lubricant) between the outer race 602 and the inner race 610.

[0048] As in Fig. As shown in Figure 6, an optional mounting bracket 608 can be positioned between the bearing 600 and the inner surface 112 of the rotor shaft 104. Additionally, an optional sleeve can be positioned around and in contact with the outer surface 116 of the mass element 108. The mounting bracket 608 is made of or contains an electrically conductive material. In such examples, the mounting bracket 608 can be an annular device having an inner compressible section that presses against the bearing 600 to hold the bearing 600 in position and to keep the outer bearing 602 electrically coupled to the rotor shaft 104. Additionally, the sleeve can be pressed onto the mass element 108 to assist in mounting the bearing 600 around the mass element 108.

[0049] In other examples, an optional electrically conductive mounting bracket can be positioned between one of the connectors here and the ground element 108. For example, Fig. Figure 7 represents a connector 700 and a mounting bracket 708. In the example of Fig. The connector 700 can be similar to one of the other connectors here, such as a bearing that has an inner and an outer race. As shown, the connector 700 is in the channel 106 of the rotor shaft 104 of Fig. 1. In particular, the connector 700 is positioned between the inner surface 112 of the rotor shaft 104 and the outer surface 116 of the mass element 108. Fig. Positioned 1.

[0050] The mounting bracket 708 from Fig. 7 is positioned between the connector 700 and the outer surface 116 of the mass element 108. For example, in the example of Fig. 7 The fastening bracket 708 extends around an outer diameter of the mass element 108 (e.g., a tube). In such examples, the fastening bracket 708 presses against an inner surface of the connector 700 and the outer surface 116 of the mass element 108 to hold the connector 700 (e.g., an inner race of a bearing) in position.

[0051] As in Fig. 7- Fig. As shown in Figure 8, the mounting bracket 708 can be an annular device having a tapered configuration. In such examples, the mounting bracket 708 has a diameter that increases from one end 710 of the mounting bracket 708 to the opposite end 712 of the mounting bracket 708. In various embodiments, the mounting bracket 708 can have a lip section 714 at the end 712 for attaching the connector 700 and dividing fingers 716 for contacting and pressing against the grounding element 108 (e.g., a tube) to maintain electrical coupling between the mounting bracket 708 and the grounding element 108.

[0052] Fig. 9 represents another example of a bearing 900, which is known as the connector 110 of Fig. 1 can be used. For example, in Fig. 9 the bearing 900 (e.g. a sacrificial bearing) an example of a rolling bearing located in the channel 106 of the rotor shaft 104 of Fig. 1 and between the inner surface 112 of the rotor shaft 104 and the outer surface 116 of the mass element 108 of Fig. 1 is positionable. In the example of Fig. 9 is the mounting bracket 608 from Fig. 6 is positioned between bearing 900 and the inner surface 112 of the rotor shaft 104. Similar to bearing 600 of Fig. 6 can the warehouse 900 of Fig. It contains 9 conventional components such as an outer race 902 which rotates with the rotor shaft 104, an inner race 906 for holding rolling elements and a seal 920 between the outer race 902 and the inner race 906 to hold a conductive grease in it.

[0053] Fig. 10 represents another exemplary current discharge arrangement 1000, which is similar to the current discharge arrangement 100 of Fig. 1 is, however, with an electrically conductive mounting bracket 1020 and plugs 1030, 1040. For example, and as in Fig. As shown in Figure 10, the current discharge arrangement 1000 generally includes the bearing 102 and the rotor shaft 104. Fig. 1, the brush 200 of Fig. 2 and a lubrication tube 1008, which runs into the channel 106 of the rotor shaft 104. In such examples, the lubrication tube 1008 is electrically conductive and grounded, as above with respect to the mass element 108 of Fig. 1 was explained. While the current discharge arrangement 1000 of Fig. Figure 10, which is shown containing the brush 200, should be noted that in further embodiments another suitable connector (e.g. one of the other connectors disclosed herein, etc.) may be used if desired.

[0054] In the example of Fig. In section 10, the brush 200 electrically couples the rotor shaft 104 to the lubrication tube 1008. This configuration allows EDM current, generated in the rotor shaft 104 due to accumulated voltage on the rotor shaft 104, and / or other circulating current in the rotor shaft 104, to flow from the rotor shaft 104 to the lubrication tube 1008 via the brush 200. Therefore, current is diverted away from the bearing 102, thus preventing damage to the bearing 102.

[0055] As in Fig. As shown in Figure 10, the mounting bracket 1020 is positioned between the body of the brush 200 and the inner surface of the rotor shaft 104. In such examples, the mounting bracket 1020 extends circumferentially along an outer diameter of the channel 106 and against the inner surface of the rotor shaft 104. In such examples, the brush 200 (e.g., the body of the brush 200) and the plug 1030, 1040 are attached to the mounting bracket 1020. In particular, the body of the brush 200 and a cup-shaped body 1032, 1042 of each plug 1030, 1040 are attached to the mounting bracket 1020.

[0056] In the example of Fig. 10. Plugs 1030 and 1040 are positioned on opposite sides of brush 200. Specifically, plug 1030 is positioned adjacent to one side of brush 200 near an outlet of lubrication tube 1008, and plug 1040 is positioned adjacent to the opposite side of brush 200 near an end of rotor shaft 104. While the current discharge arrangement 1000 of Fig. Figure 10 shows two plugs 1030, 1040, it should be acknowledged that in further embodiments more or fewer plugs and / or other suitable sealing mechanisms can be used if desired.

[0057] In certain examples, one or both plugs 1030, 1040 can prevent lubricant supplied through the lubrication tube 1008 from contacting the brush 200. For example, in the example of Fig. 10. The plugs 1030 are positioned in the channel 106 between the lubrication tube 1008 and the rotor shaft 104. In such examples, each plug 1030, 1040 includes a flexible lip seal 1034, 1036 extending from the body 1032, 1042 and contacting the lubrication tube 1008. With this configuration, the plug 1030 prevents lubricant flowing from the tube 1008 from contacting the brush 200, thus providing a lubricant-free, substantially dry environment (e.g., a cavity) for the brush 200. In various embodiments, the plug 1040 can optionally include a similar flexible lip seal.

[0058] Fig. Figure 11 represents another exemplary current discharge arrangement 1100, which is similar to the current discharge arrangement 1000 of Fig. 10, however, contains a different connector between the rotor shaft 104 and the lubrication tube 1008. For example, the current discharge arrangement 1100 contains Fig. 11 generally the bearing 102 and the rotor shaft 104 of Fig. 1, the warehouse 600 of Fig. 6 and the lubrication tube 1008, the mounting bracket 1020 and the plugs 1030, 1040 of Fig. 10. In this example, the bearing 600 electrically couples the rotor shaft 104 to the lubrication tube 1008. This allows EDM current, generated in the rotor shaft 104 due to accumulated voltage on the rotor shaft 104, and / or any other circulating current in the rotor shaft 104, to flow from the rotor shaft 104 to the lubrication tube 1008 via the bearing 600. This diverts current away from the bearing 102, thus preventing damage to the bearing 102.

[0059] Fig. Figure 12 presents an exemplary method 1200 for manufacturing a current discharge arrangement for an electric machine in an electric vehicle. During Fig. 12, which is shown and described as containing certain steps, it must be acknowledged that the procedure 1200 of Fig. 12 is an exemplary variation that can be implemented, and in further embodiments, method 1200 and / or other exemplary methods may include different steps, more or fewer steps, etc. Additionally, although method 1200 is described here with respect to certain components (e.g., the mounting bracket 1020, the lubrication tube 1008, etc.), it should be acknowledged that method 1200 can be used with other suitable components.

[0060] As in Fig. As shown in Figure 12, the process 1200 begins in step 1202, where the mounting bracket 1020 is provided. In this example, the mounting bracket 1020 is an annular device having a body 1220 that defines a retaining bracket channel 1222 passing through it. Next, in step 1204, the mounting bracket 1020 is cut. For example, and as shown in step 1204, at least one recess 1224 is cut into the body 1220 of the mounting bracket 1020.

[0061] Then, in step 1206, a connector 1226 is attached to the mounting bracket 1020 using the recess 1224. For example, in Fig. 12 of the connectors 1226 are pressed into and at least partially through the recess 1224 and locked into position. Therefore, the connector 1226 runs into the retaining bracket channel 1222, as shown in Fig. Figure 12 shows. In various embodiments, the connector 1226 can be a C-shaped brush and have a bristle configuration similar to brush 200. Fig. 2 or the brush 300 from Fig. 3. In further embodiments, the connector 1226 can be another suitable device such as a bearing, a spring-loaded connector, etc., as explained here.

[0062] In step 1208 of method 1200, a mass element is inserted into the retaining bracket channel 1222 of the mounting bracket 1020 such that it touches the connector 1226. In the example of Fig. 12 is the mass element the lubrication tube 1008, which supplies a lubricant to the channel 106 of the rotor shaft 104, as further referenced below.

[0063] In various embodiments, one or more dams can be formed, as in step 1208 of Fig. Figure 12 shows that, for example, end sections of the body 1220 of the mounting bracket 1020 can be bent inwards, pressed, etc., to form dams 1228, 1230, as shown in Figure 12. Fig. Figure 12 shows. In further examples, the dams 1228, 1230 can be welded or attached to the body 1220 of the mounting bracket 1020 in another suitable manner. In still further examples, the dams 1228, 1230 can be plugs (e.g., plugs 1030, 1040) attached to the mounting bracket 1020 or formed in another way, as explained here. Regardless of the configuration, the dams 1228, 1230 (or the plugs) prevent lubricant supplied through the tube 1008 from coming into contact with the connector 1226.

[0064] Then, in step 1210, the lubrication pipe 1008 and the mounted mounting bracket 1020, along with the connector 1226 and the dams 1228, 1230, are inserted into the channel 106 of the rotor shaft 104. After this step, the connector 1226 electrically couples the rotor shaft 104 to the lubrication pipe 1008, allowing current to flow from the rotor shaft 104 to the lubrication pipe 1008 via the connector 1226.

Claims

[1] Current discharge arrangement (1000, 1100) for an electric machine in an electric vehicle, the current discharge arrangement (1000, 1100) comprising: a rotor shaft (104) that defines an outer diameter of a channel (106); a mass element (108) positioned in the channel (106), wherein the mass element (108) is a tube (1008) extending into the channel (106) of the rotor shaft (104) and configured to supply a lubricant into the channel (106) of the rotor shaft (104); and a connector (200, 600) positioned in the channel (106) of the rotor shaft (104) and extending circumferentially between the rotor shaft (104) and the mass element (108), wherein the connector (200, 600) is configured to electrically couple the rotor shaft (104) to the mass element (108) when the rotor shaft (104) rotates, in order to allow current to flow from the rotor shaft (104) to the mass element (108) via the connector (200, 600); characterized by , that the current discharge arrangement (1000, 1100) further comprises a first and a second plug (1030, 1040) positioned in the channel (106) between the tube (1008) and the rotor shaft (104), the plugs (1030, 1040) being configured to prevent the lubricant supplied through the tube (1008) from touching the connector (200, 600), the first plug (1030) being positioned adjacent to a first side of the connector (200, 600) and the second plug (1040) being positioned adjacent to a second side of the connector (200, 600) opposite the first side; wherein the current discharge arrangement (1000, 1100) further includes a mounting bracket (1020) which runs circumferentially along the outer diameter of the channel (106) and to which the connector (200, 600) and the two plugs (1030, 1040) are attached. [2] Current discharge arrangement (1000) according to claim 1, wherein the connector (200, 600) is a brush (200) comprising a body (202) and several bristles (204) extending from the body (202). [3] Current discharge arrangement (1100) according to claim 1, wherein the connector (200, 600) is a bearing (600) positioned between the rotor shaft (104) and the mass element (108). [4] Current discharge arrangement (1000, 1100) according to claim 1, wherein the connector (200) includes a body (402) and one or more spring-loaded rods (404) configured to preload against one or more of the rotor shaft (104) and the mass element (108). [5] Method for manufacturing a current discharge arrangement (1200) for an electric machine in an electric vehicle, wherein the electric machine includes a rotor shaft (104) defining a shaft channel (106), and the method comprises: Providing a mounting bracket (1020) having a body (1220) defining a mounting bracket channel (1222) passing through it; Cutting at least one recess (1224) into the body (1220) of the mounting bracket (1020); Attaching a connector (1226) to the mounting bracket (1020) by means of the recess (1224), wherein the connector (1226) runs into the mounting bracket channel (1222); Inserting a mass element (108) into the retaining bracket channel (1222) of the mounting bracket (1020) such that it touches the connector (1226) which extends into the retaining bracket channel (1222); and Inserting the mass element (108) and the mounting bracket (1020) with the attached connector (1226) into the shaft channel (106) of the rotor shaft (104) such that the connector (1226) electrically couples the rotor shaft (104) to the mass element (108) when the rotor shaft (104) rotates, in order to allow current to flow from the rotor shaft (104) to the mass element (108) via the connector (1226).

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