Motorcycle Frame Stiffness and Aesthetics via Segmented Bracket
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Solution Overview
Problem
Conventional motorcycle frame structures face challenges in optimizing vehicle body stiffness balance, increasing weight and cost due to reduced longitudinal stiffness and torsional stiffness, while also compromising aesthetics with exposed engine components through air discharge holes.
Innovation Solution
A motorcycle design featuring a vehicle body frame with bulge portions and pivot frames that support the engine with hanging portions at two front and rear positions, incorporating an engine suspending bracket that overlaps the air discharge hole, allowing for improved stiffness balance, weight reduction, and enhanced aesthetics by hiding internal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the engine bracket has bent portions to support the engine, then the engine can be mounted, but the longitudinal stiffness of the engine bracket is reduced
Solution Approach 1:
The engine bracket is divided into multiple sections: a front bracket portion, a rear bracket portion, and a connecting portion with a bent shape. This segmentation allows the connecting portion to accommodate engine positioning requirements while the front and rear portions maintain structural stiffness for mounting support.
Solution Approach 2:
Different portions of the engine bracket have different structural characteristics optimized for their specific functions. The front and rear portions are designed with higher stiffness for mounting, while the connecting portion has a bent shape optimized for engine alignment, creating local quality variations that resolve the stiffness contradiction.
2Strength
If the plate thickness of the engine bracket is increased to improve longitudinal stiffness, then the stiffness is improved, but the weight and cost increase
Solution Approach 1:
Instead of uniformly increasing the entire bracket's thickness, the design segments the bracket into functional zones where thickness and material distribution are optimized locally - thicker and stronger where mounting stiffness is needed, thinner where engine accommodation is prioritized.
Solution Approach 2:
The engine bracket utilizes composite construction combining different materials or material densities in different portions, allowing high-strength regions for mounting while using lighter materials in non-critical areas, thus achieving required stiffness without proportional weight increase.
3Ease of manufacture
If the air discharge hole is disposed on the side surface of the cowling, then the air can be discharged, but the internal equipment is exposed and aesthetics are ruined
Solution Approach 1:
The air discharge hole is nested within a recessed region of the cowling's side surface. This nesting allows the discharge hole to function while being visually integrated into the cowling's aesthetic design, preventing exposure of internal equipment through strategic positioning within the recessed area.
4Shape
If the tightening position on the vehicle body frame side is hidden behind the radiator, then the appearance is cleaner, but removal of the engine bracket requires removing the radiator which increases labor
Solution Approach 1:
The tightening position and its associated fastening mechanism are extracted or separated from the main engine bracket structure, allowing independent access to the fastening elements. This extraction enables maintenance personnel to access and remove fasteners without necessarily removing the entire radiator assembly, thus preserving appearance while improving repairability.
Data Source
AI summary
The configuration includes: a right and left pair of main frames extending from a head pipe while widening rearward; and pivot frames that are welded to the main frames and extend toward the rear downward direction. Under the main frames, an engine is arranged. The main frame includes a hanging portion for holding and fastening the engine. In the front portion of the main frame, a bulge portion is disposed on the vehicle-widthwise outer side. The hanging portion is settable to the bulge portion.