Segmented Vehicle Frame Cross Member for Motor Unit Packaging
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Solution Overview
Problem
Existing vehicle frame structures in electric drive vehicles create dead space in the power unit chamber due to the formation of large curved portions in cross members, which hampers the reduction of empty space and complicates component placement and maintenance.
Innovation Solution
A vehicle frame structure featuring a first cross member with an intermediate member extending downward and coupling members connected to the side members, eliminating the need for large curved portions, and a second cross member to absorb collision loads, along with a torque rod to reduce motor unit oscillation, all designed to minimize dead space and enhance maintainability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the intermediate portion and coupling portions of the cross member are formed of a single continuous member, then the structural integrity is improved, but large curved portions are created leading to dead space in the power unit chamber
Solution Approach 1:
The cross member is divided into separate components: an intermediate member and coupling members. The intermediate member has a substantially U-shaped cross-section and is positioned below the motor unit, while coupling members connect it to the side members. This segmentation eliminates the need for large curved transition portions, reducing dead space in the power unit chamber while maintaining structural integrity through the coordinated arrangement of discrete components.
2Temperature
If large curved portions are formed in the cross member, then the motor unit can be positioned lower, but dead space increases and component placement becomes difficult
Solution Approach 1:
By segmenting the cross member into an intermediate member and coupling members, the design achieves low installation level for the motor unit without requiring large curved portions. The intermediate member can be positioned at the desired low level while coupling members provide the necessary structural connection, eliminating dead space that would be created by curved transitions in a continuous member design.
Solution Approach 2:
The intermediate member is given a substantially U-shaped cross-section, utilizing the vertical dimension effectively. This allows the member to achieve the necessary structural support and positioning function without requiring horizontal curvature, thereby reducing dead space in the power unit chamber while maintaining the low installation level.
3Ease of manufacture
If the cross member is formed as a single continuous member, then manufacturing is simplified, but maintainability of the motor unit is reduced due to difficult access
Solution Approach 1:
The cross member is segmented into an intermediate member and coupling members that can be assembled separately. The intermediate member is positioned below the motor unit and can be accessed from underneath the vehicle for maintenance purposes. This segmentation maintains manufacturing simplicity through standardized components while significantly improving maintainability by providing access to the motor unit area.
Solution Approach 2:
The design allows for dynamic assembly and disassembly of the intermediate member relative to the coupling members and side members. This enables the intermediate member to be removed or accessed from below the vehicle for motor unit maintenance, providing the flexibility needed for easy repair while maintaining a simple manufactured structure.
Data Source
AI summary
A vehicle frame structure includes a pair of rear side members extending along a length of a vehicle in a lower part of the vehicle, and a first cross member coupling the pair of rear side members. The first cross member includes an intermediate member and a pair of coupling members. The intermediate member extends along a width of the vehicle at a location further downward with respect to the rear side members and is located under a motor unit. The pair of coupling members respectively extend downward or diagonally downward from the respective side members toward the opposite ends of the intermediate member.