Straddle Vehicle Frame Vibration Damping via Elastic Support
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Solution Overview
Problem
Straddle-type vehicles with single-cylinder engines face challenges in reducing engine vibration transmission to the handlebar, particularly when balancers are omitted to reduce weight, leading to increased vibration and stiffness issues in the body frame.
Innovation Solution
The vehicle design modifies the body frame by eliminating engine supports from the forward and backward extensions, increasing elastic deformation, and reinforcing the down frame connection to the pipe member, while removing the pipe member to maintain strength without adding weight, and positioning the single-cylinder engine's attachment points on the up and down extensions and down frame to distribute stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a balancer is provided to damp single-cylinder engine vibration, then vibration transmission to the handlebar is reduced, but the vehicle weight increases
Solution Approach 1:
The invention extracts the vibration damping function from the traditional balancer (a separate rotating mass) and integrates it into the engine support structure itself. The engine support is designed with elastic deformation characteristics that passively absorb vibration energy, eliminating the need for a dedicated balancer component and its associated weight.
Solution Approach 2:
The engine support acts as an intermediary element between the engine and the body frame. It mediates the transmission of vibrations by incorporating elastic deformation capabilities, thereby reducing the direct transmission of engine vibrations to the handlebar while maintaining structural integrity.
2Strength
If the body frame stiffness is increased to reduce deformation under load, then structural strength is improved, but engine vibration transmission to the handlebar increases
Solution Approach 1:
The invention applies different structural qualities to different parts of the body frame. The down frame and connecting members maintain high stiffness for structural strength, while the engine support area is designed with controlled elastic deformation characteristics to damp vibrations locally, preventing their transmission to the handlebar.
Solution Approach 2:
The engine support structure incorporates dynamic elastic deformation capabilities that allow it to flex and absorb vibration energy. This dynamic response contrasts with the static rigidity of other frame components, enabling the structure to adapt to vibrational loads while maintaining overall strength.
3Stability of the object's composition
If engine supports are provided on the forward and backward extensions to reduce frame deformation, then body frame stiffness is improved, but vibration transmission to the handlebar increases
Solution Approach 1:
The invention removes the engine support from the forward and backward extensions, extracting the vibration transmission path that connects the engine to the handlebar through these extensions. The engine is instead supported solely by the down frame, which is positioned to minimize vibration transmission to the steering mechanism.
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 configuration reduces engine vibration transmission to the handlebar, maintains the strength of the down frame, and decreases the overall vehicle weight by optimizing the connection members and attachment points, thereby balancing vibration reduction and structural integrity.
Implementation Method 1
The rear end of the main frame coupling portion is located to the rear of a straight line that is parallel to the steering axis and passes through the lower end of the down frame coupling portion. This geometric configuration optimizes stress distribution and reinforces the connection between the main frame and down frame.
Implementation Method 2
Positioning the single-cylinder engine's attachment points on the up and down extensions and down frame to distribute stress effectively
Implementation Method 3
modifies the body frame by eliminating engine supports from the forward and backward extensions, increasing elastic deformation
Data Source
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AI summary
A main frame (22) of the body frame (2) includes a forward and backward extension (221) that extends rearward from a head pipe (21), and an up and down extension (222) that extends downward from the rear end of the forward and backward extension (221). The engine (3) is attached to the up and down extension (222) and a down frame (23), but not to the forward and backward extension (221). A connecting member (24) of the body frame (2) includes a main frame coupling portion (241) and a down frame coupling portion (242). The main frame coupling portion (241) is coupled to the forward and backward extension (221), and its lower end is located lower than the upper end of the engine (3). The down frame coupling portion (242) is coupled to the down frame (23), and its rear end is located to the rear of a straight line that is parallel to a steering axis and passes through the lower end of the down frame coupling portion (241) in a vehicle side view.