Snap-Fit Plastic Module Holder for Vibration-Resistant Power Electronics
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Solution Overview
Problem
Existing power electronics units for electric motor vehicle drives face challenges in achieving compactness, easy assembly, and sufficient vibration resistance while adhering to insulation specifications and avoiding complex screw handling.
Innovation Solution
A power electronics unit featuring a plate-like cooling element with a plastic module holder secured via an interlocking snap connection, allowing for easy semiconductor module mounting and reduced assembly effort, with integral or separate interlocking elements and additional securing mechanisms for robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-positive fastening elements (screws) are used to fix the power semiconductors to the cooling element, then the fastening force and vibration resistance are improved, but the assembly complexity and time increase due to complex handling and screwing operations
Solution Approach 1:
The patent replaces the traditional screw-based mechanical fastening system with a snap-in connection system. The module holder features snap-in lugs that engage with recesses in the cooling element, eliminating the need for screws and screwing operations. This substitution maintains sufficient fastening force and vibration resistance while dramatically simplifying the assembly process.
Solution Approach 2:
The module holder is designed with integrated snap-in lugs that automatically engage with the cooling element recesses during assembly. The self-aligning and self-latching nature of the snap-in connection allows the assembly to service itself without requiring precise manual positioning or additional fastening operations, thereby reducing assembly complexity and time.
2Device complexity
If terminal blocks are used to press power semiconductors against the cooling plate, then the assembly is simplified, but the fastening force and secure mounting are reduced
Solution Approach 1:
The module holder is constructed from fiber-reinforced plastic, creating a composite material structure that combines the advantages of plastic (integration capability, damping properties) with the strength of fiber reinforcement. This composite construction enables the holder to provide both simplified assembly through integration and sufficient fastening force through the reinforced structure, resolving the contradiction between assembly simplicity and mounting security.
Solution Approach 2:
The snap-in lugs are designed with curved engagement surfaces that provide mechanical advantage during the snap-in process. The curvature allows for gradual engagement and distribution of forces, enabling the connection to achieve secure mounting with reduced assembly effort compared to rigid linear fastening methods.
3Productivity
If the power electronics unit is made compact to improve specific performance, then the volume is reduced, but the insulation specifications (air gaps and creepage distances) become more difficult to maintain
Solution Approach 1:
The module holder acts as a flexible intermediary structure between electrical components. Its plastic construction allows for integrated insulation barriers and creepage path design within the holder itself, enabling compact arrangements while maintaining required insulation distances. The holder can be designed with built-in insulation features that adapt to compact geometries without compromising electrical safety.
4Strength
If screws are used to fasten the module holder to the cooling element, then the fastening force is improved, but the assembly effort and time increase
Solution Approach 1:
The patent replaces the multi-step screw fastening mechanism with a single-step snap-in connection. The snap-in lugs on the module holder engage with recesses in the cooling element through a simple insertion motion, eliminating the need for aligning holes, inserting screws, and tightening fasteners. This substitution maintains adequate fastening force while reducing assembly time significantly.
Solution Approach 2:
The snap-in lugs are pre-formed as integral parts of the module holder during molding, rather than requiring separate fastening components to be attached during assembly. This preliminary formation of fastening features eliminates additional assembly steps and reduces overall assembly time while maintaining connection strength.
Data Source
AI summary
A power electronics unit for an electric motor of a motor vehicle drive, having a plate-like cooling element, at least one semiconductor module and a module holder which consists of plastic and secures the at least one semiconductor module relative to the cooling element. The module holder is fixed to the cooling element via an interlocking snap connection.