Rear Subframe Vertical Pillar for Arm Support Rigidity
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Solution Overview
Problem
In vehicle rear subframe structures, it is challenging to secure high rigidity of the front cross member and side members while maintaining sufficient space for arm support portions, especially in narrow spaces like the lower portion of a rear seat pan where connecting these components is difficult.
Innovation Solution
A rear subframe configuration featuring a grid pattern of front and rear cross members and side members with a vertical-wall-shaped pillar portion connecting the front cross member to the upper and lower side members, forming upper and lower arm support portions, which allows direct load transmission to the side members and front cross member, enhancing rigidity and positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
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 installation space is reduced to meet passenger comfort and low hip point requirements, but it becomes difficult to secure high rigidity of the front cross member and side member, and to secure space for upper-arm and lower-arm support portions
Solution Approach 1:
The patent introduces a vertical-wall-shaped pillar portion that extends in the vehicle height direction (vertical dimension) to connect the front cross member and side member. This vertical connection provides a new dimensional approach to achieving rigid connection in the narrow horizontal space, transforming the problem from a 2D horizontal layout constraint to a 3D solution utilizing the vertical dimension.
Solution Approach 2:
The connection structure is segmented into multiple functional parts: the front cross member, the side member, and the intermediate pillar portion. This segmentation allows each component to be optimized independently while maintaining overall rigidity, with the pillar portion serving as a dedicated vertical connector that resolves the space constraint issue.
2Shape
If a rear subframe is disposed in a narrow space of a lower portion of a rear seat pan, then the installation space is reduced to meet passenger comfort and low hip point requirements, but it becomes difficult to secure space for upper-arm and lower-arm support portions
Solution Approach 1:
The pillar portion utilizes the vertical dimension (vehicle height direction) to provide arm support portions, allowing upper-arm and lower-arm support functions to be achieved without requiring additional horizontal space. This vertical arrangement resolves the space conflict by moving support functions into the height dimension.
3Strength
If an H-shaped lower arm is provided to secure rigidity of the rear subframe, then the rigidity is improved, but the device complexity increases
Solution Approach 1:
The patent merges the connection function and the support function into a single integrated pillar portion structure. This vertical-wall-shaped pillar serves multiple purposes: connecting the front cross member to the side member, providing upper-arm support, and providing lower-arm support, thereby reducing overall structural complexity compared to separate H-shaped lower arm components.
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 on each of both ends of the front cross member, and on each of rear ends of the upper side members. The rear subframe further includes a vertical-wall-shaped pillar portion held and fixed between a lateral portion of the front cross member in the vehicle width direction and the upper side member, and extending in the vehicle width direction. A lower portion of the pillar portion is connected to the lower side member, an upper-arm support portion is formed on an upper portion of the pillar portion, and a lower-arm support portion is formed on a lower portion of the pillar portion.