Removable Cradle Crossmember for Electric Motor Assembly Access

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Solution Overview

Problem

Accessing and assembling the electric motor and its wiring in electric or hybrid vehicles is difficult due to the presence of the rear crossmember, which complicates both assembly and subsequent maintenance.

Innovation Solution

A cradle design with a removable rear crossmember that can be detached during assembly and maintenance, allowing easy access to the electric motor and wiring by screwing them onto the motor before mounting it on the cradle, and then attaching the crossmember using mechanical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rear crossmember is permanently fixed on the cradle body, then the structural strength and rigidity of the cradle is improved, but the accessibility to the electric motor and its wiring during assembly and maintenance deteriorates

Engineering Contradiction:
Improvestructural strengthVSAvoidaccessibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The cradle crossmember is divided into two separate parts: a fixed base structure attached to the cradle body, and a removable crossmember portion that can be detached. This segmentation allows the fixed part to maintain structural strength while the removable part can be taken away to improve accessibility to the electric motor and wiring during assembly and maintenance operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The crossmember transitions from a static, permanently fixed component to a dynamic component that can change its state between fixed and removable. This allows the cradle structure to adapt its configuration based on operational needs: fixed during normal operation for strength, and removable during assembly/maintenance for accessibility.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the crosspiece is permanently fixed, then the structural rigidity of the cradle is improved, but the ease of assembly and maintenance of the electric motor deteriorates

Engineering Contradiction:
Improvestructural rigidityVSAvoidease of assembly
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The crossmember is segmented into a fixed base portion and a removable portion, allowing the fixed base to maintain structural rigidity while the removable portion can be detached to facilitate easy assembly and maintenance of the electric motor and associated components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The removable crossmember portion can be temporarily discarded (removed) during assembly and maintenance operations to access the electric motor, and then recovered (reinstalled) afterward to restore the complete cradle structure. This temporary removal and recovery process simplifies manufacturing and maintenance while preserving structural integrity.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If the crosspiece is permanently fixed, then the structural integrity of the cradle is improved, but the cost and complexity of assembly and maintenance increases

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By segmenting the crossmember into fixed and removable portions, the design maintains structural integrity through the fixed base while reducing assembly and maintenance complexity through the removable portion. This segmentation creates a simpler overall system that balances reliability with ease of service.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dynamic capability of the crossmember to transition between fixed and removable states reduces the complexity of assembly and maintenance procedures. Workers can easily remove the crossmember portion when needed and reinstall it afterward, avoiding complex disassembly of the entire cradle structure while preserving structural integrity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3974294B1Method for assembling an electric or hybrid motor vehicle
Publication Date: 2026.04.22 RENAULT SA
  • EP3974294B1 patent drawingFigure 1
  • EP3974294B1 patent drawingFigure 2~3

AI summary

Cradle (12) for a motor vehicle (11), comprising a body (14), in particular intended to be assembled to a body (40), characterized in that the cradle (12) comprises a removable cross member (17) and in that it comprises a first configuration in which said removable cross member (17) is mounted on the body (14), a first and a second end (17a, 17b) of said removable cross member (17) being in particular mounted respectively on a first and a second end (14a, 14b) of the body (14), and in that it comprises a second configuration in which said removable cross member (17) is disassembled, which allows the extraction of said removable cross member (17).