Bus bar assembly, inverter device, and electric driving device for driving vehicle
The busbar assembly with insulator collars addresses assembly errors by securing fastening means, enhancing safety and reducing reassembly needs in electric drive devices.
Patent Information
- Application Number
- JP2025004957
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-01-15
- Filing Date
- 2025-01-14
- Publication Date
- 2025-07-28
AI Technical Summary
Existing busbar assemblies in electric drive devices for vehicles are prone to human or mechanical errors during assembly, leading to potential mechanical damage and electrical short circuits due to misalignment or loosening of fastening means.
A busbar assembly design featuring at least two busbars with through holes and an insulator collar that surrounds the busbars, forming a physical restriction to prevent fastening means from unintentionally coming off, ensuring secure assembly and reducing the risk of mechanical damage and electrical shorts.
The design enhances assembly safety by maintaining fastening means in a controlled position, reducing the need for reassembly and minimizing risks of electric shock, thereby saving time and costs.
Smart Images
Figure 2025110398000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a busbar assembly. The present invention also relates to an inverter device and an electric drive device for vehicle drive.
Background Art
[0002] A busbar assembly serves to connect high-voltage components such as an inverter device and a rotating electrical machine in an electric drive device for vehicle drive. It is known to provide a plurality of busbars partially surrounded by an insulator in the busbar assembly. Thereby, the busbar assembly forms a single component for the assembly process. In the assembly process, the busbar is electrically and mechanically connected to the high-voltage component, for example, by screwing the busbar. The connection can be made manually or automatically, for example, by a robot.
[0003] Due to human or mechanical error, the fixing means may deviate from its intended connection position, and the fixing of the busbar may fail. When the fixing means falls into the housing of the component, it is necessary to perform an overall reassembly so that the fixing means does not cause mechanical damage or electrical short circuit inside the housing.
[0004] Therefore, an object of the present invention is to improve the assembly of the busbar in an electric drive device for a vehicle, particularly to increase the safety.
Summary of the Invention
[0005] The above problem is solved by a busbar assembly comprising at least two busbars each having a current flow direction and a cross-sectional area with respect to the current flow direction, the cross-sectional area having opposing first and second long side surfaces and two opposing small side surfaces, each busbar having a through hole extending from the first long side surface to the second long side surface, at least two busbars, and an insulator surrounding the long side surfaces and the small side surfaces of each busbar along a part of the current flow direction and forming an opening for each busbar on the first long side surface to enable access to the through hole, the insulator being a collar extending from the first long side surface to the opposite side and forming a collar surrounding the opening.
[0006] The busbar assembly according to the present invention comprises at least two busbars and an insulator. Each of the busbars has a current flow direction and a cross-sectional area with respect to the current flow direction. The cross-sectional area has opposing first and second long side surfaces. The cross-sectional area has two opposing small side surfaces. Each busbar has a through hole extending from the first long side surface to the second long side surface.
[0007] The insulator surrounds the long side surfaces and the small side surfaces of each busbar along a part of the current flow direction. The insulator forms an opening for each busbar on the first long side surface to enable access to the through hole. The insulator forms a collar. The collar extends to the opposite side of the first long side surface. The collar surrounds the opening.
[0008] The present invention is based on the idea of additionally using an insulator to prevent fastening means, such as screws, from loosening when assembling the busbar assembly to another electrical component. For this purpose, the collar forms a physical restriction around the opening of the insulator. This restriction prevents the fastening means from unintentionally coming off the busbar assembly.
[0009] As an advantage of the present invention, the bus bar assembly makes the assembly of the bus bar assembly safer because the fastening means remains in a controlled position even when a human or mechanical error occurs. In particular, this eliminates the need to reassemble to remove lost fastening means. Therefore, the manufacturing time and cost in case of an error are reduced, and the risk of electric shock to the worker performing the reassembly can be avoided.
[0010] The bus bar is typically composed of a metal, such as copper. Preferably, each bus bar is configured to conduct a current of at least 50 A, preferably at least 100 A, more preferably at least 200 A. The current flow direction is typically perpendicular to the cross-sectional area. The cross-sectional area is preferably rectangular or radially rectangular.
[0011] The insulator can be composed of a polymer. Preferably, the insulator is molded around the bus bar.
[0012] Preferably, the collar surrounds a single gap around the opening. Here, the gap can define a common space for the bus bar and prevent the fastening means from coming off the bus bar assembly.
[0013] Advantageously, the collar includes a first wall section and a second wall section that face each other in the current flow direction. Here, the first wall section may have a recess facing the second wall section between each pair of adjacent openings. In particular, for each recess of the first wall section, the second wall section has a recess facing the recess of the first wall section.
[0014] The insulator of the bus bar assembly according to the present invention can surround the free end of each bus bar with respect to the current flow direction. The free end is preferably close to the through hole of each bus bar. This free end may be referred to as the first free end.
[0015] Also, each bus bar may extend from the first long side surface to the second long side surface and may include a further through hole that is not covered by the insulator. The further through hole may be close to the second free end opposite the first free end.
[0016] Preferably, the insulator includes a through hole disposed outside the collar between each pair of adjacent bus bars. The through holes in the insulator can help fix the bus bar assembly without making an electrical connection.
[0017] In a preferred embodiment, the bus bars are arranged such that, in each pair of adjacent bus bars, the small side surfaces face each other. In other words, the bus bars are arranged such that their small side surfaces are aligned. Additionally or alternatively, the bus bars may be arranged in a common plane.
[0018] Preferably, the bus bar assembly according to the present invention is provided with three bus bars. This is particularly useful in applications where a three-phase AC current flows through the bus bars. Of course, other numbers of bus bars are also possible. For example, there may be two bus bars (suitable for DC applications), four bus bars, five bus bars, or six bus bars, etc.
[0019] The above problems are further solved by an inverter device including an inverter housing structure having an assembly opening, an inverter circuit having two terminals that are AC terminals and DC terminals, and a bus bar assembly according to the present invention, wherein the bus bar assembly is connected to one of the terminals, and the opening of the insulator is positioned so as to be able to access the through hole of the bus bar through the assembly opening.
[0020] The inverter circuit may include a plurality of semiconductor switching elements, such as IGBTs or MOSFETs, connected by a half bridge between the DC terminal and the AC terminal.
[0021] The inverter device may further include fastening means, which are particularly screws. Each screw may have a shaft and a head. Each screw extends through one of the through holes. The collar and the assembly opening form a gap therebetween, and the gap is smaller than the diameter of the head.
[0022] Furthermore, the inverter device may include a printed circuit board. The collar is disposed between the assembly opening and the printed circuit board. Due to the protective function of the busbar assembly having the collar, the printed circuit board can be safely disposed near the busbar. Control electronics for the inverter circuit may be mounted on the printed circuit board.
[0023] Preferably, the busbar assembly is connected to the AC terminal.
[0024] The above problem is further solved by an electric drive device for driving a vehicle, the electric drive device comprising a housing having a mechanical housing structure, an inverter device according to the present invention, and a rotary electric machine disposed inside the mechanical housing structure, wherein the inverter housing structure forms a part of the housing of the electric drive device, and the inverter device is configured to supply a polyphase AC voltage to the electric machine via the AC terminal.
[0025] The electric machine may be a permanent magnet synchronous motor or an electrically excited synchronous motor. Alternatively, the electric machine may be an induction motor.
[0026] The above problem is further solved by a vehicle comprising an electric drive device according to the present invention configured to drive the vehicle.
[0027] The vehicle may be a battery electric vehicle (BEV) or a fuel cell vehicle. Alternatively, the vehicle is a hybrid vehicle having an additional combustion engine.
[0028] The following discloses further details and advantages of the present invention with reference to the drawings. The drawings schematically show the following.
Brief Description of the Drawings
[0029]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Embodiments for Carrying Out the Invention
[0030] FIG. 1 is a schematic diagram of an embodiment of an electric drive device 1.
[0031] The electric drive device 1 includes a housing 2, an embodiment of an inverter device 3, and a rotating electrical machine 4. The housing 2 includes a mechanical housing structure 5 in which the electrical machine 4 is disposed inside, and an inverter housing structure 6 formed by the inverter device 3.
[0032] The inverter device 3 includes an inverter circuit 7 having two terminals, an AC terminal 8 and a DC terminal (not shown), and is configured to supply a three-phase AC voltage to the electrical machine 4 via the AC terminal 8. In particular, the electrical machine 4 includes a stator 9 and a rotor 10. Exemplarily, the electrical machine 4 is a permanent magnet synchronous motor or an electrically excited synchronous motor. Alternatively, the electrical machine may be an induction motor.
[0033] The inverter device 3 is configured to supply a polyphase AC voltage to the stator winding. As further shown in FIG. 1, the inverter device 3 includes a printed circuit board 11 on which control electronics for controlling the inverter circuit 7 is mounted. The electric drive device 1 further includes a bus bar 12 so as to connect the electric machine 4 to the inverter device 3 or its AC terminals 8, respectively. The bus bar 12 is connected to the electric machine 4 and is disposed in the machine housing structure 5. The inverter device 3 includes an embodiment of a bus bar assembly 13. The embodiment of the bus bar assembly 13 is electrically and mechanically connected to the bus bar 12 disposed in the machine housing structure 5 by fastening means 14. Exemplarily, the fastening means 14 is realized by a screw.
[0034] More specifically, the inverter housing structure 6 is fastened to the machine housing structure 5 by a plurality of fastening elements 15, for example screws.
[0035] FIG. 2 is a partial cross-sectional view of an embodiment of the electric drive device 1.
[0036] The inverter housing structure 6 has an assembly opening 16 that enables access to the bus bar assembly 13. When assembling the electric drive device 1, the screw 14 for connecting the bus bar assembly 13 to the bus bar 12 can be applied through the assembly opening 16. As further understood from FIG. 2, the bus bar assembly 13 is disposed between the printed circuit board 11 and the assembly opening 16.
[0037] FIGS. 3 and 4 show examples of the bus bar assembly 13. FIG. 3 is a perspective view of an embodiment of the electric drive device 1 showing an embodiment of the bus bar assembly 13 in a mounted state, and FIG. 4 is a partial top view thereof.
[0038] The bus bar assembly 13 according to the embodiment includes three bus bars 18. Each bus bar 18 has a current flow direction 19 and a cross-sectional area perpendicular to the current flow direction 19. The cross-sectional area has opposing first and second long side surfaces 20a and 20b, and two opposing small side surfaces 21a and 21b. The second long side surface 20b and the second small side surface 21b are not visible in FIG. 3. In the present embodiment, the bus bars 18 are arranged in a common plane such that, illustratively, the small side surfaces 21a and 21b face each other.
[0039] Each bus bar 18 has a through hole 22. The through hole 22 is partially visible in FIG. 3 but not visible by the screw 14 in FIG. 4. The through hole 22 extends from the first long side surface 20a to the second long side surface 20b.
[0040] Furthermore, each bus bar 18 includes an insulator 23 that surrounds the long side surfaces 20a, 20b and the small side surfaces 21a, 21b of each bus bar 18 along a part of the current flow direction 19. The insulator 23 forms an opening 24 for each bus bar 18 in the first long side surface 20a, enabling access to the through hole 22. Furthermore, the insulator 23 is a collar 25 that extends to the opposite side of the second long side surface 20a and forms a collar surrounding the opening 24.
[0041] Specifically, the collar 25 surrounds a single gap 26 around the opening 24 and includes a first wall section 27a and a second wall section 27b that face each other with respect to the current flow direction 19. The first wall section 27a has a recess a28 facing the second wall section 27b between each pair of adjacent openings 24. Similarly, the second wall section 27b has a recess 28b facing the recess a28 between each pair of adjacent openings 24.
[0042] More specifically, the insulator 23 surrounds the first free end (not visible in the insulator 23 in FIGS. 3 and 4) of each bus bar 18 with respect to the current flow direction 19. Each bus bar 18 extends from the first long side surface 20a to the second long side surface 20b and has a further through hole 29 that is not covered by the insulator 23. The through hole 29 is arranged at the second free end 30 on the opposite side of the first free end. The through hole 29 serves to connect the bus bar assembly 13 to the AC terminal 8 (see FIG. 1) of the inverter device 3.
[0043] Furthermore, the insulator 23 includes through holes 31 arranged outside the collar 25 in each pair of adjacent bus bars 18. The through holes 31 serve to fix the bus bar assembly 13 inside the inverter housing structure 6 (see FIG. 1).
[0044] As best understood from FIGS. 2 and 4, the opening 24 of the insulator 23 is positioned so as to provide access to the through hole 22 of the bus bar 18 via the assembly opening 16. In particular, the shape of the assembly opening 16 corresponds to the shape of the collar 25. A gap 32 is formed between the collar 25 and the assembly opening 16.
[0045] FIGS. 5 and 6 are partial cross-sectional views of the loosened screw 14 and the embodiment of the electric drive device 1, respectively.
[0046] The screw 14 has a shaft 33 and a head 34, respectively. The gap 32 between the collar 25 and the assembly opening 16 is smaller than the diameter of the head 34 of the screw 14 so that the screw 14 does not fall into the housing 2 during assembly. In particular, it can be avoided that the screw 14 contacts the printed circuit board 11 (see FIG. 2) and damages the electrical components or causes a short circuit.
[0047] FIG. 7 is a schematic diagram of an embodiment of the vehicle 100.
[0048] Vehicle 100 includes the electric drive device 1 according to the above-described embodiment. The electric drive device 1 is configured to propel the vehicle 100. The vehicle 100 includes wheels 101 directly or indirectly connected to the electric drive device 1, for example via a transmission, whereby the wheels 103 rotate. According to the embodiment, the vehicle 100 is a battery electric vehicle (BEV). Alternatively, the vehicle 100 may additionally include a combustion engine to form a hybrid vehicle. Further, the electric vehicle 100 may include a fuel cell that supplies power to the electric drive device 1.
Claims
Claim 1 A bus bar assembly (13), comprising at least two bus bars (18), each having a current flow direction (19) and a cross-sectional area with respect to the current flow direction (19), the cross-sectional area having opposing first and second long side surfaces (20a, 20b) and two opposing small side surfaces (21a, 21b), and each bus bar having a through hole (22) extending from the first long side surface (20a) to the second long side surface (20b). An insulator (23) surrounding the long side surfaces (20a, 20b) and the small side surfaces (21a, 21b) of each bus bar (18) along a part of the current flow direction (19) and forming an opening (24) for each bus bar (18) on the first long side surface (20a) to enable access to the through hole (22). The insulator (23) is a collar (25) extending from the first long side surface (20a) to the opposite side, forming a collar (25) surrounding the opening (24). A bus bar assembly. Claim 2 The bus bar assembly according to claim 1, wherein the collar (25) surrounds a single gap (26) around the opening (24). Claim 3 The collar (25) comprises a first wall section (27a) and a second wall section (27b) facing each other with respect to the current flow direction (19). The bus bar assembly according to claim 1 or 2, wherein the first wall section (27a) has a recess (28a) facing the second wall section (27b) between each pair of adjacent openings (24). Claim 4 The bus bar assembly according to claim 3, wherein for each recess (28a) of the first wall section (27a), the second wall section (27b) has a recess (28b) facing the recess (28a) of the first wall section (27a). Claim 5 The bus bar assembly according to any one of claims 1 to 4, wherein the insulator (23) surrounds the free end of each bus bar (18) with respect to the current flow direction (19). Claim 6 The bus bar assembly according to any one of claims 1 to 5, wherein each bus bar (18) extends from the first long side surface (20a) to the second long side surface (20b) and comprises a further through hole (29) not covered by the insulator (23). Claim 7 The bus bar assembly according to any one of claims 1 to 6, wherein the insulator (23) includes a through hole (31) disposed outside the color (25) between each pair of adjacent bus bars (18).
8. The bus bar assembly according to any one of claims 1 to 7, wherein the bus bars (18) are arranged such that the small side surfaces (21a, 21b) face each other in each pair of adjacent bus bars (18).
9. The bus bar assembly according to any one of claims 1 to 8, wherein three bus bars (18) are provided in the bus bar assembly (13).
10. An inverter device (3), an inverter housing structure (6) having an assembly opening (16), an inverter circuit (7) having two terminals which are an AC terminal (8) and a DC terminal, and a bus bar assembly (13) according to any one of claims 1 to 9, wherein the bus bar assembly (13) is connected to one (8) of the terminals, and the opening (24) of the insulator (23) is positioned so as to be accessible to the through hole (22) of the bus bar (18) through the assembly opening (16).
11. Further comprising fastening means which are particularly screws (14), each screw having a shaft (33) and a head (34), each screw extending through one of the through holes (22), wherein a gap (32) is formed between the collar (25) and the assembly opening (16), and the inverter device according to claim 10, wherein the gap (32) is smaller than the diameter of the head (34).
12. Further comprising a printed circuit board (11), and the inverter device according to claim 10 or 11, wherein the collar (25) is disposed between the assembly opening (16) and the printed circuit board (11).
13. The inverter device according to any one of claims 10 to 12, wherein the bus bar assembly (13) is connected to the AC terminal (8).
14. An electric drive device (1) for driving a vehicle (100), having a housing (2) with a mechanical housing structure (5), an inverter device (3) according to any one of claims 10 to 13, and a rotating electric machine (4) disposed inside the mechanical housing structure (5). The inverter housing structure (6) forms part of the housing (2) of the electric drive device (1), The inverter device (3) is an electric drive device configured to supply a polyphase AC voltage to the electromechanical machine (4) via the AC terminal (8).
15. A vehicle (100) comprising the electric drive device (1) according to claim 14, configured to drive the vehicle (100).