Straddle-Type Vehicle Frame Handle Clearance Design

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Solution Overview

Problem

The existing vehicle body frame structures for straddle-type vehicles, such as motorcycles, are not designed flexibly enough to prevent interference between the handle and the main frames during steering operations, limiting the ease of steering and flexibility in frame design.

Innovation Solution

The vehicle body frame structure includes a head pipe with a steering shaft, upper and lower frames extending rearward from the head pipe, and coupling frames that create a retraction space between them, allowing the upper frame to protrude upward and preventing interference with the handle, enabling more flexible frame design and easier steering operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the main frames are designed to prevent interference with the handle during steering operations, then the ease of operation is improved, but the design flexibility of the vehicle body frame deteriorates

Engineering Contradiction:
Improveease of steering operationVSAvoiddesign flexibility of vehicle body frame
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The upper frame is positioned to extend above the handle in the vertical dimension, allowing the handle to pass underneath during steering operations. This spatial arrangement in the height direction resolves the interference problem while maintaining design flexibility in the horizontal plane.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The main frame is divided into upper and lower frames with coupling frames connecting them, creating distinct functional zones. The upper frame specifically addresses handle clearance while the lower frame maintains structural integrity, allowing independent optimization of each segment.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the upper frame extends upward to create space for device placement, then the adaptability for device mounting is improved, but the complexity of the frame structure increases

Engineering Contradiction:
Improvedevice placement flexibilityVSAvoidframe structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The upper frame serves multiple functions: it maintains structural connectivity between head pipe and rear section, creates clearance for handle steering operations, and provides mounting space for various devices. This multi-functionality reduces the need for additional separate structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The upper frame integrates the structural support function with the device mounting platform function, combining what could be separate elements into a single unified structure that reduces overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3067263B1Vehicle body frame structure of a straddle-type vehicle
Publication Date: 2020.04.15 KAWASAKI JUKOGYO KK
  • EP3067263B1 patent drawingFigure 1
  • EP3067263B1 patent drawingFigure 2
  • EP3067263B1 patent drawingFigure 3

AI summary

A vehicle body frame structure of a straddle-type vehicle (100) comprises a head pipe (2) into which a steering shaft (105) connected to a handle (121) is inserted; and a pair of main frames (3) extending rearward and outward in a vehicle width direction from the head pipe (2) in such a manner that the main frames are spaced apart from each other in the vehicle width direction. Each of the main frames (3) includes an upper frame (11) extending rearward from an upper portion of the head pipe (2), and a lower frame (12) extending rearward from a lower portion of the head pipe (2). Between the upper frame (11) and the lower frame (12), a retraction space (53) which is located inward in the vehicle width direction relative to an end portion of the handle (121) in a turn operation state is provided.