Motor Vehicle Subframe Curved Shell Reinforcement Fatigue Strength
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Solution Overview
Problem
Motor vehicle subframes face challenges in achieving high fatigue strength while maintaining a low weight, particularly under dynamic loads such as vibrations, which existing designs struggle to address effectively.
Innovation Solution
The subframe incorporates reinforcing elements made of sheet metal, designed as curved shells with overlapping ends that are welded to the longitudinal and cross members, reducing mechanical tension and enhancing fatigue strength, along with a weight-reduced construction of the cross member and longitudinal members, and optionally using light metal materials like aluminum for further weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rigid reinforcement elements are used to increase fatigue strength, then the subframe can withstand vibrations better, but the weight of the subframe increases
Solution Approach 1:
The patent uses sheet metal reinforcing elements with curved shell geometry instead of traditional rigid reinforcements. These thin-walled curved shells provide the necessary fatigue strength under vibrational loads while maintaining low weight, directly resolving the contradiction between reliability and weight.
Solution Approach 2:
The reinforcing elements are designed with curved surfaces rather than flat or angular geometries. This curvature optimizes the distribution of mechanical tensions under vibrational loads, enhancing fatigue strength while using minimal material, thus improving reliability without significantly increasing weight.
2Weight of stationary object
If the subframe structure is simplified to reduce weight, then manufacturing and assembly are easier, but the fatigue strength under dynamic loads decreases
Solution Approach 1:
Instead of uniformly reinforcing the entire subframe structure, the patent applies sheet metal reinforcing elements only at specific critical locations where fatigue occurs under vibrational loads. This localized reinforcement maintains overall structural simplicity and low weight while providing targeted fatigue resistance.
3Strength
If larger reinforcing elements are added to increase rigidity, then the subframe can better withstand mechanical loads, but the installation space for drive units is reduced
Solution Approach 1:
The thin-walled sheet metal reinforcing elements provide the necessary rigidity and strength to withstand mechanical loads while occupying minimal space. Their thin-walled construction ensures that they reinforce the subframe structure without encroaching on the installation space required for drive units.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design significantly increases the fatigue strength of the subframe while maintaining a low weight, providing a larger installation space for drive units and improving rigidity, thus effectively addressing the limitations of existing subframe designs.
Implementation Method 1
the overlapping ends with the cross member or one of the longitudinal members cohesively connected, preferably welded
Data Source
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AI summary
The invention relates to a subframe for a motor vehicle, comprising longitudinal members (8.1, 8.2) spaced apart from one another, at least one cross member (4) connecting the longitudinal members, and reinforcing elements connected to the longitudinal members and the cross member and made of sheet metal. To ensure that such a subframe offers high fatigue strength at a relatively low weight, the reinforcing elements (9, 10) are, according to the invention, composed of a first reinforcing element (9) and a second reinforcing element (10), which are designed as curved shells and have overlapping ends (9.1, 10.1), wherein the overlapping ends (9.1, 10.1) are metallurgically connected, preferably welded, to the cross member or one of the longitudinal members (8.2).