Rear Subframe Front Cross Member Inclined Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rear subframe structures face challenges in securing high rigidity in the vehicle width direction while maintaining sufficient space for lower-arm support, particularly in narrow spaces where connecting a front cross member and side members is constrained, such as in the lower portion of a rear seat pan.
Innovation Solution
A rear subframe configuration featuring a front cross member with a closed section extending in the vehicle width direction, inclined laterally to downwardly extend the front portion, and a lower-arm support portion formed on the rear portion of the lateral members, allowing for enhanced rigidity and space for lower-arm support without narrowing the swing range, utilizing a grid pattern connection of members and a pillar portion for load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a rear subframe is disposed in a narrow space of a lower portion of a rear seat pan where it is impossible to connect a front cross member and a side member, then the layout constraints are satisfied, but high rigidity in the vehicle width direction cannot be secured
Solution Approach 1:
The patent introduces a downwardly extending portion from the front cross member that protrudes into the narrow space below the rear seat pan. This vertical dimension utilization allows the front cross member to effectively extend downward, creating a stable triangular configuration with the lower arm support portion and side member, thereby achieving high rigidity in the vehicle width direction without requiring additional lateral space.
Solution Approach 2:
The front cross member is segmented into a main body portion and a downwardly extending portion. This segmentation allows the downwardly extending portion to independently occupy the narrow space below the rear seat pan, providing structural support and rigidity enhancement without interfering with the overall compact layout of the rear subframe assembly.
2Strength
If a downwardly extending portion is provided from the front cross member to secure rigidity, then high rigidity in the vehicle width direction is achieved, but the space for lower-arm support may be reduced
Solution Approach 1:
The downwardly extending portion is strategically positioned and dimensioned to provide rigidity enhancement only where needed - in the narrow space below the rear seat pan. The lower arm support portion is separately provided on the side member at an optimized location that maintains sufficient clearance and support functionality. This localized approach ensures that rigidity reinforcement does not encroach upon the lower-arm support space.
3Device complexity
If the front cross member is linearly extended to connect with the vehicle body support portion, then the structure is simplified, but it is difficult to secure both sufficient closed sectional structure and high rigidity in the vehicle width direction
Solution Approach 1:
Instead of linearly extending the front cross member in the horizontal plane, the patent extends a portion of it downward in the vertical dimension. This creates an effective L-shaped configuration that provides both the structural continuity needed for simplified design and the vertical leverage required for enhanced rigidity in the vehicle width direction through the downwardly extending portion.
Data Source
AI summary
A rear subframe structure is provided with a rear subframe configured such that a front cross member, a rear cross member, a pair of left and right upper side members, and a pair of left and right lower side members are connected; and a vehicle-body mounting portion formed. The rear subframe further includes a lower-arm support portion. The front cross member has a closed section, and a front portion of the closed section extends downwardly by forward and downward inclination of a left lateral portion and a right lateral portion of the front cross member. The lower-arm support portion is formed on a lower rear portion of the left lateral portion and the right lateral portion of the front cross member. The upper side member is connected to an upper rear portion of the left lateral portion and the right lateral portion of the front cross member.