Motorcycle Frame Side Wall Sections for Rigidity
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Solution Overview
Problem
The challenge is to enhance the frame rigidity of a motorcycle without increasing its size in the vehicle-width direction, which is typically achieved by widening the intervals between the left and right frames, but this makes it difficult for the rider to place their feet on the ground stably.
Innovation Solution
The design incorporates wide, flat side wall sections that cover the engine unit from the sides and have ribs extending inwardly, with upper and lower edges positioned above and below the cylinder head, and a wind introduction passage to enhance cooling and rigidity, while maintaining a compact vehicle width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the intervals between the left and right upper or lower frames are widened in a vehicle-width direction to enhance frame rigidity, then frame rigidity is improved, but the size of the whole vehicle in a vehicle-width direction becomes large, making it difficult for a rider to put feet on the ground stably
Solution Approach 1:
The patent transitions from a conventional tubular frame structure to a plate-like side wall section structure that extends in the vertical direction. By changing the structural dimension from horizontal spacing dependence to vertical extension with inward ribs, the frame achieves enhanced rigidity without increasing vehicle width. The side wall sections extend vertically with ribs extending inwardly to provide structural reinforcement while maintaining a compact vehicle width.
Solution Approach 2:
The patent applies local reinforcement through ribs that extend inwardly from the side wall sections. Instead of uniformly widening the entire frame structure, the ribs provide localized structural reinforcement at critical areas where rigidity is needed. This allows the frame to achieve high rigidity through targeted local strengthening rather than global dimension increase.
2Strength
If the intervals between the left and right frames are widened to improve frame rigidity, then frame rigidity is enhanced, but the seat width increases, making it difficult for a rider to put feet on the ground stably
Solution Approach 1:
The patent resolves this contradiction by changing the structural approach from horizontal frame spacing to vertical plate-like side wall sections with inward ribs. This dimensional change allows the frame to achieve necessary rigidity through vertical extension and internal rib reinforcement rather than through increased horizontal spacing, thereby maintaining a narrower seat width that enables stable foot placement.
Solution Approach 2:
The inwardly extending ribs provide localized structural reinforcement at critical stress points in the side wall sections. This local quality enhancement allows the frame to achieve high rigidity without requiring increased overall dimensions, thus maintaining ease of operation and stable foot placement for the rider.
Data Source
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AI summary
The present application relates to a motorcycle, comprising a body frame and an engine unit (7) fixed to the body frame, the body frame including a head pipe (3) and left and right frame sections (12) extending from the head pipe (3), wherein the left and the right frame sections (12) include left and right side wall sections (12a) extending in a longitudinal direction and/or in a vertical direction of the motorcycle, and the left and the right side wall sections (12a) are disposed on left and right sides of the engine unit (7) and have at least a portion which overlaps at least a portion of the engine unit (7) when viewed from a lateral side of the motorcycle.