Motorcycle Swingarm Bracket Local Thickness for Rigidity
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Solution Overview
Problem
Existing swingarm support structures face challenges in achieving required supporting rigidity without increasing weight, particularly when the swingarm bracket is disposed inward of the swingarm in the vehicle widthwise direction, as they require higher strength, which can lead to weight gain or excessive strength in other areas.
Innovation Solution
A swingarm support structure configuration that includes a pair of left and right vertical frame pieces and swingarm brackets with opposing portions spaced apart in the vehicle widthwise direction, where the pivot is supported by these opposing portions, allowing for increased rigidity by thickening only necessary areas without increasing the overall thickness of the swingarm bracket, and optionally featuring different rigidities and coupling portions to inhibit deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the swingarm bracket is disposed inward of the swingarm in the vehicle widthwise direction, then the vehicle profile becomes slimmer, but the swingarm bracket requires higher supporting strength leading to weight increase
Solution Approach 1:
The swingarm bracket is designed with non-uniform thickness distribution, where the thickness is increased specifically at the pivot support portion to provide required strength, while other portions maintain smaller thickness to reduce overall weight. This local quality differentiation allows the bracket to achieve necessary supporting strength without proportionally increasing overall weight.
2Strength
If the thickness of the swingarm bracket is increased to ensure supporting strength, then the supporting rigidity is improved, but the weight increases and excessive strength is created in other areas
Solution Approach 1:
The swingarm bracket employs variable thickness design where specific regions (particularly the pivot support portion) have increased thickness for high strength requirements, while other regions have reduced thickness. This creates a non-uniform structure that concentrates material where needed, achieving high supporting rigidity without proportionally increasing overall weight.
Solution Approach 2:
The swingarm bracket is divided into multiple portions with different thickness characteristics - the pivot support portion has greater thickness while other portions have smaller thickness. This segmentation allows differential strength distribution, ensuring that each region has appropriate strength for its specific functional requirements without unnecessary weight.
3Strength
If the swingarm bracket is disposed outward of the swingarm in the vehicle widthwise direction, then the supporting strength is improved, but the vehicle profile becomes wider
Solution Approach 1:
By positioning the swingarm bracket inward and using local thickness increase at the pivot support portion, the design achieves high supporting strength in the critical area without increasing the overall bracket dimensions that would widen the vehicle profile. The local quality approach allows strength concentration without external dimension increase.
Data Source
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AI summary
A pair of left and right vertical frame pieces 1b, 1b constituting a part of a vehicle body frame FR extend in a vertical direction. A pair of left and right swingarm brackets 9L, 9R are fixed to the left and right vertical frame pieces 1b, 1b, respectively. A pivot 16 is supported by the swingarm brackets 9L, 9R swingably supports a swingarm 12 outward of the swingarm brackets 9L, 9R in a vehicle widthwise direction. Each of the left and right swingarm brackets 9L, 9R includes left and right opposing portions 320, 340 disposed so as to be spaced apart in the vehicle widthwise direction. The pivot 16 is supported by the left and right opposing portions 320, 340 of each of the swingarm brackets 9L, 9R.