Stator End Disc Jumpers for Low-Profile Winding Connections
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Solution Overview
Problem
The packaging of electric machine stators is hindered by the tall bus bars resulting from numerous leads and connections, which complicates space utilization in vehicle engine compartments, especially with increased slots per pole per phase, parallel wires, or series connections.
Innovation Solution
A stator design featuring a cylindrical core with radially extending slots, end disc with dog holes, and bent jumpers that connect in-slot portions, allowing for reduced axial length and outer diameter, and requiring fewer welds, facilitated by a method involving an end disc with tool retaining structures and a dog for bending terminal portions to form low-profile jumpers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If numerous leads and connections are provided for increased slots per pole per phase, parallel wires, and series connections, then the winding connectivity and electrical performance are improved, but the bus bar height in axial direction increases and packaging space is reduced
Solution Approach 1:
The patent transitions connections from the axial dimension (vertical bus bars) to the radial dimension (horizontal jumpers). By placing jumpers radially outward from slot centers and bending them circumferentially around dog holes in the end disc, the connection geometry moves to a different spatial dimension, achieving compact axial profile while maintaining electrical connectivity for increased slots per pole per phase and parallel/series configurations.
Solution Approach 2:
The end disc with dog holes serves as an intermediary structure that enables compact jumper connections. The dog holes provide predetermined bending locations for terminal portions, acting as mediators that guide the formation of low-profile jumpers. This intermediary structure allows numerous connections to be made in a compact radial arrangement rather than requiring tall axial bus bars.
2Adaptability or versatility
If numerous jumpers and series connections are provided for increased parallel wires per phase, then the electrical performance is improved, but the manufacturing complexity and number of welds increase
Solution Approach 1:
The end disc with dog holes is prepared in advance with predetermined bending locations. Terminal portions are bent around these pre-positioned dog holes before final welding, establishing the jumper geometry in advance. This preliminary action simplifies the welding process by pre-positioning all connection points, reducing the complexity of coordinating numerous welds for increased parallel wires per phase.
Solution Approach 2:
The terminal portions are bent around dog holes that are integral to the end disc structure, using the end disc's own geometry to guide the bending process. The dog holes serve as self-contained bending fixtures, eliminating the need for external bending tools or complex positioning fixtures, thereby simplifying manufacturing for numerous jumpers and series connections.
3Reliability
If traditional bus bar connections are used for numerous leads, then the electrical connections are reliable, but the stator outer diameter and axial length increase
Solution Approach 1:
The patent replaces traditional axial bus bar connections with radial jumper connections. By bending terminal portions circumferentially around dog holes in the end disc, connections are made in the radial dimension rather than extending axially. This dimensional change maintains electrical reliability through proper weld connections while significantly reducing stator outer diameter and axial length for compact packaging.
Solution Approach 2:
The jumpers are nested within the radial space between the slot centers and the end disc outer periphery. Terminal portions are bent around dog holes that are positioned within the end disc, nesting the connection geometry within the existing stator structure rather than extending outward with tall bus bars, thereby reducing overall stator volume.
Data Source
AI summary
A stator for an electric machine comprises a cylindrical stator core, windings positioned on the stator core, and an end disc positioned an end of the stator core. The stator core defines an inner diameter and an outer diameter. A plurality of slots are formed in the core and extend radially from the inner diameter toward the outer diameter. The windings include in-slot portions, end turns, and at least one jumper. The end disc defines a plurality of slots aligned with the slots of the stator core and at least one dog hole removed from the slots of the end disc. The at least one jumper is bent circumferentially around the dog hole and connects two of the in-slot portions of the windings.