Electric Vehicle Auxiliary Frame Spacer Reduces Bending Stress
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Solution Overview
Problem
Conventional auxiliary frames for electric vehicles face component failure due to bending stresses at cross bridge connections, leading to increased material usage and weight, which exacerbates chassis wear and weight-related issues.
Innovation Solution
An auxiliary frame design featuring a first and second shell element with a cavity, a cross bridge connected via a screwed connection, and a sleeve-like spacer element that reinforces the frame by defining a shared load path between the cross bridge mount and vehicle body connection, reducing bending stress while maintaining or slightly increasing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sheet metal thickness of the auxiliary frame is increased to prevent component failure from bending stresses, then reliability is improved, but weight increases
Solution Approach 1:
The auxiliary frame is divided into shell elements and a separate cross bridge component. The cross bridge is a distinct element that can be optimized independently for strength without increasing the thickness of the entire shell structure, thereby maintaining reliability while controlling weight.
Solution Approach 2:
The auxiliary frame combines different materials or material configurations in the shell elements and cross bridge. This allows strategic placement of higher strength materials only where bending stresses are critical, rather than uniformly increasing thickness throughout the entire frame, thus improving reliability without proportional weight increase.
2Strength
If sheet metal thickness is increased to achieve higher bending strength, then strength is improved, but weight increases
Solution Approach 1:
The cross bridge and specific shell element regions are designed with enhanced strength properties only where bending stresses occur during operation. Other regions of the auxiliary frame maintain standard thickness, optimizing the strength-to-weight ratio by applying material enhancement locally rather than globally.
Solution Approach 2:
Different material compositions or structural configurations are used in the cross bridge and shell elements to achieve high bending strength in critical areas without uniformly increasing weight across the entire auxiliary frame structure.
3Weight of moving object
If vehicle weight is reduced by using thinner sheet metal, then weight is improved, but reliability deteriorates due to bending stresses
Solution Approach 1:
By separating the cross bridge as a distinct component from the shell elements, the design allows the shell elements to be thinner and lighter while the cross bridge provides the necessary structural reinforcement for reliability under bending loads, achieving weight reduction without sacrificing stability.
Solution Approach 2:
The combination of thinner shell elements with a reinforced cross bridge creates a composite structure that maintains overall reliability while reducing total weight, as the high-strength materials are concentrated only where structurally necessary.
Data Source
AI summary
An auxiliary frame for a vehicle including a first shell element and a second shell element, rigidly connected to the first shell element, to define a cavity. The auxiliary frame includes a cross bridge for bearing a vehicle drive unit. The cross bridge is connected by a screwed connection to the first shell element and/or to the second shell element. The auxiliary frame includes a sleeve-like spacer element for the inserting of a screw for vehicle body connection. The spacer element is arranged at one of its ends at a through-hole of the first shell element and extends within the cavity in the direction of a through-hole of the second shell element. The spacer element has a sleeve-like portion for receiving a screw of the screwed connection of the cross bridge.