Self-Steering Axle Knuckle With Integrated Drum Brake Mounting
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Solution Overview
Problem
Existing self-steering axle/suspension systems for heavy-duty vehicles face complex manufacturing processes and increased costs due to the need for multiple welds and complex spindle end preparations for mounting discrete brake spiders, which reduces the strength and longevity of the knuckle and its pivotal connections, and results in increased weight and potential premature failure.
Innovation Solution
A knuckle design with an integrally formed structure for mounting drum brake system components, featuring a forged and machine-finished spindle friction-welded directly to the knuckle with a single weld, minimizing the distance from the king pin to the wheel hub and using a discrete tie rod arm bolted via axial and radial bolting to reduce size and weight, while eliminating the need for multiple welds and complex manufacturing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple welds and complex spindle end preparations are used to mount discrete brake spiders, then the mounting capability is achieved, but the manufacturing complexity and cost increase while the strength and longevity of the knuckle decrease
Solution Approach 1:
The brake mounting structure is merged with the knuckle body itself, eliminating the need for separate brake spiders and multiple welds. The knuckle incorporates integral brake shoe mounting surfaces and anchor pin provisions directly in its structure, combining the functions of the knuckle and brake mounting components into a single unified part.
Solution Approach 2:
The discrete brake spider component is extracted and eliminated from the design. Instead of using a separate brake spider that requires multiple welds to attach to the knuckle, the brake mounting functionality is taken out and integrated directly into the knuckle structure through forged features.
2Strength
If multiple welds are used to attach the spindle to the knuckle, then the attachment is achieved, but the manufacturing cost increases and the overall strength decreases
Solution Approach 1:
The spindle attachment features are merged into the knuckle body through integral forging. The knuckle is forged with built-in spindle mounting surfaces and alignment features that eliminate the need for separate attachment operations and multiple welds, reducing both manufacturing cost and improving structural integrity.
3Strength
If the distance from king pin to wheel hub is increased, then the wheel mounting capability is achieved, but the stress and fatigue on the knuckle increase
Solution Approach 1:
The knuckle structure is preliminarily designed with optimized geometry during the forging process to minimize the distance from king pin to wheel hub. The integral forging allows precise control of feature locations, placing the wheel hub mounting surfaces as close as possible to the king pin pivot point to reduce moment arms and associated stresses.
4Ease of manufacture
If a discrete brake spider is used, then the drum brake system mounting is achieved, but the manufacturing process becomes complex and costly
Solution Approach 1:
The brake mounting functionality is merged into the knuckle structure itself. The knuckle is forged with integral brake shoe mounting surfaces, anchor pin locations, and cam shaft mounting features, eliminating the need for a separate brake spider component and simplifying both the structure and manufacturing process.
Solution Approach 2:
The knuckle is designed as a multi-functional component that simultaneously serves as the steering pivot structure, the spindle mounting structure, and the brake system mounting structure. This universal design eliminates the need for separate discrete components for each function, reducing overall system complexity.
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 reduces manufacturing complexity and cost, increases the strength and longevity of the knuckle and its pivotal connections, minimizes stress and fatigue, and provides a robust structure capable of handling varying components and configurations, while reducing the overall weight of the heavy-duty vehicle.
Implementation Method 1
a spindle that is a-forged, machine finished, and then friction welded directly to the knuckle with only the single friction weld
Data Source
AI summary
A knuckle for a heavy-duty vehicle self-steering axle/suspension system that includes integrally formed structure for mounting components of a drum brake system. The knuckle includes a spindle that is welded directly to the knuckle and a discrete tie rod arm bolted to the knuckle.