Stator Busbar Terminal Layout for Bending-Resistant Connection
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Solution Overview
Problem
Existing electric machines face issues with terminal resilience against axial and transverse forces during connection to a power supply, leading to potential bending and damage, especially during assembly when terminal connectors are susceptible to deformation.
Innovation Solution
The electric machine incorporates a busbar unit with a busbar holder made of electrically insulating material featuring grooves and stepped terminal portions, where the third terminal portion is positioned above the holder, reducing bending moments and providing axial support through support projections, thus minimizing damage from applied forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the terminal connector is made long and axially projecting for connection with power supply, then the connection capability is improved, but the terminal becomes susceptible to bending and damage from axial and transverse forces
Solution Approach 1:
The terminal portions are arranged in multiple dimensions (axial direction and radial direction) rather than a single linear arrangement. The first terminal portion extends axially, the second terminal portion extends radially, and the third terminal portion extends axially again, creating a stepped three-dimensional configuration that distributes mechanical stresses across different spatial dimensions
Solution Approach 2:
The terminal connector is divided into multiple segmented terminal portions (first, second, and third terminal portions) rather than a single continuous structure. Each segment is positioned at different locations and orientations, allowing independent stress distribution and reducing the bending moment on any single section
Solution Approach 3:
The busbar holder acts as an intermediary structure that receives and distributes axial forces from the terminal portions. The holder includes grooves that receive the busbars and support projections that extend axially to contact and support the terminal portions, transferring loads away from the vulnerable terminal sections
2Strength
If support projections are added to the busbar holder to support terminal portions, then the resistance to bending is improved, but the device complexity increases
Solution Approach 1:
The support projections are merged with the busbar holder structure rather than being separate components. The support projections are formed as integral parts of the holder body, eliminating the need for additional fasteners, brackets, or mounting structures that would increase assembly complexity
Solution Approach 2:
The support projections are strategically positioned only at specific locations where terminal portions require support, rather than providing uniform support throughout the entire structure. The grooves are also positioned specifically to receive busbars at critical stress points
Data Source
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AI summary
The invention relates to an electric machine (1) comprising a rotor (2) arranged to rotate about a rotation axis (3), a stator (4) including a plurality of stator coils (5), a busbar unit (6) arranged to supply a drive current to the respective coils (5). The busbar unit (6) includes a plurality of busbars (7) each connected to at least one of the stator coils (5) and comprising a generally axially projecting terminal connector (8) for axial connection with a power supply connector (14), a busbar holder (9) made of an electrically insulating material extending in a direction perpendicular to the axial direction (10), whereby the busbar holder (9) comprises a plurality of grooves (11) which receive the respective busbars (7). The busbars (7) comprise a strip portion (7a) extending perpendicularly to the axial direction within one of the plurality of grooves (11), and at least one of the busbars (7) having a first terminal portion (7b) extending in the axial direction away from the strip portion (7a) followed by a second terminal portion (7c) extending from and perpendicular to the first terminal portion (7b), followed by a third terminal portion (7d) extending from the second terminal portion (7c) in the axial direction (10), whereby the third terminal portion(7d) is connected to or forms the axially projecting terminal connector (8), and at least one of the second or third terminal portions (7c, 7d) or the axially projecting terminal connector (8) contacts the busbar holder (9), whereby the third terminal portion (7d) is positioned above the busbar holder (9)in the axial direction.