Electric Motor Stator Busbar Alignment for Secure Clamping Contact
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Solution Overview
Problem
In brushless electric motors, incorrect alignment of busbars with contact slots during assembly can lead to improper clamping contacts, which may not be detected by end-of-line tests and can result in motor failure due to busbar breakage during operation.
Innovation Solution
The stator design incorporates an interconnection element with insertion pockets that project axially beyond the contact element, ensuring that misaligned busbars come into contact with non-conductive plastic, preventing incorrect electrical connections and ensuring reliable assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insertion pocket is dimensioned to allow complete insertion of the contact element, then reliable electrical contact is achieved, but the press-in tool cannot maintain constant contact during the press-fit process
Solution Approach 1:
The insertion pocket is designed with a stepped structure that creates different axial levels: a first axial level for receiving the contact element and a second axial level that protrudes beyond the contact element. This dimensional differentiation allows the press-in tool to maintain constant contact with the contact element's upper edge during insertion while ensuring the lower edge remains accessible for electrical connection, thus resolving the contradiction between reliable electrical contact and press-fit process control.
2Adaptability or versatility
If tolerance deviations occur during assembly, then busbars may become misaligned with contact slots, but current can still flow through incorrect contact paths
Solution Approach 1:
The insertion pocket's stepped structure acts as an intermediary mechanism between the contact element and the busbar. The second axial level that protrudes beyond the contact element serves as a positioning reference that guides the busbar into correct alignment with the contact slot. This intermediary structure prevents incorrect contact even when tolerance deviations occur, as the protruding level physically blocks misaligned busbars from making electrical contact.
3Reliability
If the contact element is completely immersed in the insertion pocket, then electrical contact is secured, but the upper edge is not accessible for press-in tool engagement
Solution Approach 1:
The insertion pocket is segmented into two distinct axial levels: the first axial level receives and secures the contact element for electrical contact, while the second axial level protrudes beyond the contact element to provide an accessible upper edge for press-in tool engagement. This segmentation allows both functions—electrical contact stability and press-in tool accessibility—to be simultaneously achieved without interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures perfect electrical contact between busbars and contact slots, preventing motor failure by ensuring correct alignment and secure clamping during assembly, even with tolerance deviations.
Implementation Method 1
The insulation displacement contact of the contact element has a cutting edge which, when inserted into the insertion pocket, cuts through the insulation of the wire portion of the coil winding located in the first slot
Implementation Method 2
In addition to applying a certain axial press-in force to the contact element, a defined press-in depth is also required to ensure reliable contacting of the wire portion
Implementation Method 3
the contact element has an axially extending contact slot into which a busbar of a contact device can be inserted or plugged for electrical clamping contact
Data Source
AI summary
A stator of an electric motor has a number of stator teeth carrying a coil winding; a circular ring-shaped interconnection element having a number of insertion pockets with contact elements inserted therein, each having at least one insulation displacement contact; and a contact device which is connected to the interconnection element. The contact device has a number of bus bars corresponding to the number of phases. Each bus bar is inserted, or can be inserted, into a contact slot of one of the contact elements in clamping contact. The insertion pockets have an insertion slot which is open on one axial side and has a first slot for guiding the wire portions and a second slot for receiving the respective bus bar.