Axle Subframe Fastening System Hardness Gradient
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Solution Overview
Problem
Existing fastening systems for connecting an axle subframe to a vehicle body are prone to subframe slipping, leading to noise and assembly difficulties, and are costly due to the need for fully tempered sleeves, which are not robustly connected and can be distorted, reducing tolerance compensation and increasing manufacturing expenses.
Innovation Solution
A fastening system featuring a support part with a higher hardness than the sleeve, allowing for secure connection without direct contact, using a tempered support part and a non-tempered sleeve with a structured surface for improved adhesion and noise reduction, enabling easy assembly and cost-effective production by avoiding the need for full hardening of all components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sleeves are completely tempered to reduce wear, then hardness and wear resistance are improved, but manufacturing cost increases significantly
Solution Approach 1:
The support part is made with higher hardness (tempered) only where it contacts the body, while the sleeve remains softer (non-tempered). This local differentiation of material properties reduces manufacturing cost while maintaining wear resistance at the critical contact interface.
2Reliability
If sleeves are made harder than the body to prevent wear, then wear resistance is improved, but the risk of subframe slipping and noise increases
Solution Approach 1:
The support part has higher hardness than the sleeve, creating a hardness gradient where the softer sleeve prevents slipping and noise while the harder support part resists wear at the body contact interface.
3Stability of the object's composition
If the axle subframe is distorted, then assembly flexibility is reduced, but the required tolerance compensation is restricted making assembly difficult
Solution Approach 1:
The support part is designed with adjustable position and orientation parameters, allowing it to be adapted to slight distortions of the axle subframe. This flexibility in geometric parameters enables assembly even when the subframe is not perfectly aligned.
4Device complexity
If the support part and sleeve are made as a single component, then device complexity is reduced, but the ability to provide different hardness levels is lost
Solution Approach 1:
The fastening system is divided into separate support part and sleeve components, allowing each to be manufactured with different material properties (hardness) optimized for their specific functions, while remaining simple enough to assemble together.
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
The system provides a secure, cost-effective connection that prevents subframe slipping, reduces noise and wear, and allows for easy assembly and repair, even with slight distortions, while being more economical than traditional methods.
Implementation Method 1
the support part having a contact surface for contacting the body, the support part being harder than the sleeve
Implementation Method 2
the bearing part having at least one structured surface
Data Source
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AI summary
The invention relates to a fastening system (1) for connecting an axle subframe (2) to a vehicle body, comprising a support part (3) with a body side (4), a subframe side (5), and a support recess (6), and a sleeve (7) with a first end region (8), a second end region (9), and a sleeve recess (10). The subframe side (5) of the support part (3) can be arranged on a first side (11) of a first wall (12) of the axle subframe (2), and the second end region (9) of the sleeve (7) can be arranged on a second wall (13) of the axle subframe (2) such that the support recess (6) and the sleeve recess (10) are arranged coaxially with each other. The support recess (6) and the sleeve recess (10) are designed to accommodate a shaft of a fastening element for connecting the axle subframe (2) to the vehicle body.The body side (4) has a contact surface (14) for contact with the body, wherein the support part (3) has a greater hardness than the sleeve (7).