Stator Tooth and U-Shaped Coil Body Fixation for Long Motors
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Solution Overview
Problem
The clamping force of existing stator coil bodies decreases as the axial length of the stator increases, leading to unreliable force-locking fixation.
Innovation Solution
A stator design with radially divided teeth and a U-shaped coil body that is force-lockingly fixed between the tooth root and tooth head, using channels in the coil body for winding guidance and a winding shield with a predetermined bending point for radial guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coil body is force-lockingly fixed to the tooth neck using clamping force, then the coil body is secured to the tooth, but the clamping force decreases as the axial length of the stator increases, leading to unreliable fixation
Solution Approach 1:
The patent transitions from a one-dimensional clamping force approach (radial direction only) to a two-dimensional fixation approach by adding tangential dimension through the oversize feature. The coil body is fixed not only by radial clamping force but also by tangential interference fit, creating a combined force-locking and form-locking connection that remains effective regardless of stator axial length.
Solution Approach 2:
The patent employs a composite fixation mechanism combining elastic plastic material (coil body) with metal tooth structure. The plastic material's resilience provides continuous clamping force, while the oversize feature creates mechanical interlocking. This composite approach of material properties and geometric features ensures reliable fixation independent of stator length.
2Strength
If the clear width between the limbs is reduced to increase clamping force, then the fixation strength improves, but plastic deformation or breakage of the coil body occurs
Solution Approach 1:
The patent applies different geometric characteristics to different parts of the coil body. The region at the end of the tooth neck features an oversize (larger clear width) to reduce stress concentration and prevent deformation, while the main clamping region maintains sufficient interference fit for strong fixation. This localized quality variation allows high clamping force without causing plastic deformation or breakage.
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
The solution provides a reliable and consistent force-locking fixation of the coil body to the stator tooth, maintaining stability across varying stator lengths.
Implementation Method 1
the limbs, due to the resilient property of the plastic, exert a clamping force on the tooth neck, the clamping force force-lockingly holding the coil body on the tooth
Data Source
AI summary
A stator of an electric motor includes a tooth and a coil body. The tooth can be radially divided, from a central axis of the stator, into consecutive portions being a tooth root, a tooth neck and a tooth head. The tangential dimensions of the tooth root and tooth head project beyond those of the tooth neck. The coil body is U-shaped and, after attachment to the tooth, at least partially axially and radially covers the portions. The coil body can be force-lockingly secured to the tooth, between the tooth root and the tooth head, in a radial direction relative to the central axis. An electric motor having the stator is also provided.