One-Piece Rear Frame Casting for EV Stiffness and Crashworthiness

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Solution Overview

Problem

The existing rear frames of electric vehicles suffer from reduced stiffness due to mechanical fasteners like self-piercing rivets and flow drill screws, which increases impact energy absorption and complicates assembly.

Innovation Solution

A rear frame designed as a unitary one-piece structure by casting, eliminating the need for mechanical fasteners and joints, thereby enhancing stiffness and crashworthiness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If mechanical fasteners (self-piercing rivets, flow drill screws) are used to join rear side members and crossmembers, then assembly is enabled, but stiffness of the vehicle rear structure is reduced

Engineering Contradiction:

Improveassembly capabilityVSAvoidstiffness of vehicle rear structure

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent merges multiple separate components (rear side members and crossmembers) into a single integrated rear frame structure. This eliminates the need for mechanical fasteners and joints, thereby resolving the contradiction by maintaining full assembly capability while preventing stiffness reduction that would occur with fastener connections.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integrated rear frame is designed with distinct functional zones including mounting regions for suspension dampers, battery compartments, and seat mounting areas. This segmentation allows the single-piece structure to maintain specialized functions while avoiding the need for mechanical joints between components.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If multiple separate components are joined together, then adaptability and mounting flexibility are improved, but device complexity and number of parts increase

Engineering Contradiction:

Improvemounting flexibilityVSAvoidnumber of parts

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The integrated rear frame serves multiple functions within a single structure: it provides structural support, contains mounting regions for suspension dampers, includes battery compartments, and offers seat mounting capabilities. This multi-functionality maintains adaptability while eliminating the need for multiple separate parts.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

By combining multiple functional components into one integrated rear frame, the patent reduces device complexity while preserving mounting flexibility through strategically designed mounting regions and interfaces within the unified structure.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4570628A1Rear frame for vehicle

Publication Date: 2025.06.18 HYUNDAI MOTOR CO LTD

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AI summary

An embodiment rear frame (10) includes a pair of side portions (11) spaced apart from each other in a width direction of a vehicle, each side portion (11) having a damper receptacle (23) in which a suspension damper is mounted, a first cross portion (12) connecting front portions of the pair of side portions (11), and a second cross portion (13) connecting rear portions of the pair of side portions (11), wherein the pair of side portions (11), the first cross portion (12), and the second cross portion (13) together are a unitary one-piece structure.