Vehicle Subframe Structure with Vertical Cross Beams for Torsional Stiffness

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Solution Overview

Problem

Existing subframe structures in new energy automobile manufacturing lack sufficient strength, particularly in terms of lateral stiffness, NVH performance, and load-bearing resistance.

Innovation Solution

A subframe structure featuring a ring frame with a front cross beam, rear cross beam, left longitudinal beam, and right longitudinal beam, along with upper and lower cross beams that are fixedly connected to the side walls of the longitudinal beams, enhancing the force transmission path and load-bearing capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional subframe structure with only front and rear cross beams is used, then the device complexity is low, but the strength and load-bearing capacity are insufficient

Engineering Contradiction:
Improveload-bearing capacityVSAvoidstructure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent adds upper and lower cross beams in the vertical dimension to the conventional front-rear cross beam structure. This dimensional expansion creates a three-dimensional rigid framework that significantly enhances load-bearing capacity and torsional stiffness while maintaining reasonable structural complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The subframe employs composite construction by integrating multiple beam components (front cross beam, rear cross beam, upper cross beam, lower cross beam) into a unified rigid framework, creating a composite structural system that achieves superior strength characteristics

Inventive Principle:
Principle #40Composite materials

2Reliability

If the subframe structure is simplified, then the ease of manufacture is high, but the NVH performance deteriorates

Engineering Contradiction:
ImproveNVH performanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The subframe is segmented into distinct functional components (front cross beam, rear cross beam, upper cross beam, lower cross beam) that can be manufactured separately and then assembled through welding, allowing for specialized manufacturing processes for each component while achieving superior overall NVH performance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple beam structures into an integrated rigid framework that works synergistically to improve NVH performance, combining the advantages of each beam component into a unified structure that enhances vibration and noise isolation

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If additional cross beams are added to enhance strength, then the load-bearing capacity improves, but the weight increases

Engineering Contradiction:
Improvetorsional strengthVSAvoidsubframe weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The upper and lower cross beams are strategically positioned at critical locations where torsional and vertical loads are most significant, providing localized reinforcement that maximizes torsional strength while minimizing unnecessary weight addition across the entire subframe structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

By adding beams in the vertical dimension, the structure achieves enhanced torsional rigidity through three-dimensional load distribution, allowing the subframe to resist twisting forces more effectively without requiring proportional increases in material quantity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4494977A1Subframe structure and vehicle
Publication Date: 2025.01.22 XIAOMI EV TECH CO LTD
  • EP4494977A1 patent drawingFigure 1
  • EP4494977A1 patent drawingFigure 2
  • EP4494977A1 patent drawingFigure 3

AI summary

A subframe structure and a vehicle. The subframe structure includes a ring frame (1) including a front cross beam (11) and a rear cross beam (12) spaced apart in a front-rear direction, and a left longitudinal beam (13) and a right longitudinal beam (14) spaced apart in a left-right direction, the left longitudinal beam (13) is connected to left ends of the front cross beam (11) and the rear cross beam (12) respectively, and the right longitudinal beam (14) is connected to right ends of the front cross beam (11) and the rear cross beam (12) respectively; and an upper cross beam (2) and a lower cross beam (3) spaced apart in an up-down direction, the upper cross beam (2) and the lower cross beam (3) are fixedly connected to the left longitudinal beam (13) and the right longitudinal beam (14).