Straddle Vehicle Frame Segmentation for Engine Rigidity and Air Cleaner Space
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Underbone straddle-type vehicles face challenges in increasing engine displacement without compromising the rigidity of the frame and the volumetric capacity of the air cleaner, as thicker subframes are required to support the heavier engine, but this reduces the air cleaner's size and capacity.
Innovation Solution
A straddle-type vehicle design featuring a main frame with a rectangular cross-sectional shape, thinner down frames connected to the main frame, and a specific arrangement of seat and reinforcing frames to distribute load effectively, allowing for a larger engine while maintaining sufficient frame rigidity and increasing air cleaner capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the left and right subframes are made thicker to increase rigidity for supporting a bigger engine, then the rigidity of the frame is improved, but the volumetric capacity of the air cleaner becomes smaller
Solution Approach 1:
The patent divides the subframe into two separate components: the main subframe and the down frame. The down frame is a thinner member that extends from the subframe toward the centerline, creating a segmented structure that provides rigidity support while leaving space for the air cleaner. This segmentation allows the air cleaner to be positioned between the down frames rather than between the thicker subframes alone.
Solution Approach 2:
The down frame extends in a lateral direction toward the vehicle centerline, adding a dimensional element to the frame structure. This lateral extension creates space in the lateral dimension where the air cleaner can be positioned, effectively utilizing the space between the down frames without requiring the subframes themselves to be thicker.
2Power
If the engine displacement is increased to improve power, then the power of the vehicle is improved, but the size and weight of the engine and air cleaner increase
Solution Approach 1:
By segmenting the support structure into subframe and down frame components, the patent enables better spatial arrangement of the engine and air cleaner. The thinner down frames create more available space for these components, allowing for more efficient packaging that can accommodate larger engines without proportionally increasing overall vehicle weight.
Solution Approach 2:
The lateral extension of the down frame toward the centerline utilizes previously unavailable space in the lateral dimension. This creates additional room for engine and air cleaner placement, enabling larger displacement engines to be installed without compromising vehicle weight balance or requiring thicker, heavier support structures.
3Strength
If the left and right subframes extend inward in a vehicle lateral direction to improve rigidity, then the rigidity is improved, but the distance between the subframes becomes smaller and the volumetric capacity of the air cleaner becomes smaller
Solution Approach 1:
The patent segments the support function between the subframe (which maintains lateral positioning) and the down frame (which extends inward toward the centerline). This segmentation allows the inward-extending element (down frame) to provide rigidity through its lateral orientation while the air cleaner is positioned in the space between these down frames, effectively utilizing the created geometry.
Solution Approach 2:
The down frame acts as an intermediary element between the subframe and the centerline. It provides the necessary structural rigidity by extending laterally inward, while simultaneously creating a defined space that serves as the mounting location for the air cleaner. The down frame mediates between the conflicting requirements of rigidity and air cleaner space.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A straddle-type vehicle (1) includes a main frame (32) having a rectangular cross-sectional shape, a left seat frame (40L) including a left first portion (41L) extending rearward and obliquely downward from the main frame (32), and a left second portion (42L) extending rearward and obliquely upward from the left first portion (41L), a right seat frame (40R) including a right first portion (41R) extending rearward and obliquely downward from the main frame (32), and a right second portion (42R) extending rearward and obliquely upward from the right first portion (41R), a left down frame (50L) being thinner than the left seat frame (40L), a right down frame (50R) being thinner than the right down frame (40R), and an air cleaner (70) disposed rearward relative to an engine (90) and disposed between the left and right seat frames (40L, 40R) and the left and right down frames (50L, 50R).