Straddle-Type Vehicle Frame Assembly with Orthogonal Fastener Constraints
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Solution Overview
Problem
The existing connection method for vehicle body frames in straddle-type vehicles, such as motorcycles, requires significant correction for assembling errors, increasing the burden and complexity of the assembly process due to the need for precise alignment and distortion correction.
Innovation Solution
The implementation of separate connection portions with orthogonal restricting directions for fastener members allows for directional error tolerance, enabling easier assembly by permitting displacement within specified ranges, thereby reducing the burden of correcting main frame distortions and increasing the stiffness of the rear frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fastener members are inserted in the vehicle width direction into all connected portions, then the rear frame is connected to the main frame, but the assembling burden increases due to the need to correct main frame distortion
Solution Approach 1:
The connection structure is segmented into multiple connected portions (first and second connected portions) with different restricting directions. The first connected portion restricts movement in the first direction while the second connected portion restricts movement in the second direction, allowing assembling errors in other directions to be tolerated without requiring distortion correction of the main frame.
Solution Approach 2:
Different connected portions are designed with different local qualities - specifically, different restricting directions. The first connected portion has restricting capability in the first direction while the second connected portion has restricting capability in the second direction, enabling selective error tolerance in different spatial dimensions.
2Strength
If multiple fastener members are used to connect the rear frame to the main frame, then the connection strength is improved, but the device complexity increases
Solution Approach 1:
The connection structure is divided into multiple independent connected portions, each handled by a separate fastener member. This segmentation allows each fastener to be installed independently in its specific restricting direction, maintaining connection strength while organizing the complexity into manageable, modular units.
Solution Approach 2:
The connection structure incorporates dynamic flexibility by allowing the rear frame to have limited movement freedom in directions not restricted by the fastener members. This dynamic capability reduces the need for overly rigid and complex connection structures, as the system can naturally accommodate assembling errors through controlled movement in non-restricted directions.
Data Source
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AI summary
Provided is a vehicle body frame structure which can reduce a burden in the assembling operation of a straddle-type vehicle (100). The vehicle body frame structure comprises a main frame (3); and a rear frame (4) connected to the main frame (3) and extending rearward from the main frame (3). The main frame (3) includes a first member (21) and a second member (23) which are connected to each other. The main frame includes a first connection portion (41) and a second connection portion (42) which are spaced apart from each other in a direction perpendicular to a vehicle width direction. The first connection portion (41) and the second connection portion (42) are provided at the first member (21) and the second member (23), respectively. The rear frame (4) includes a first connected portion (43) connected to the first connection portion (41) by a first fastener member (91), and a second connected portion (44) connected to the second connection portion (42) by a second fastener member (92). The restricting direction of the first fastener member (91) is orthogonal to the restricting direction of the second fastener member (92).