Plastic Injection-Molded Motorcycle Rear Frame

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Solution Overview

Problem

Existing motorcycle rear frames are costly, time-consuming to produce, and have limited dimensional accuracy and material choices, with complex assembly and restricted shape and color options, while also requiring additional components like air filter boxes and fuel tanks.

Innovation Solution

A motorcycle rear frame formed from two plastic halves by injection molding, creating a closed box shape with internal and external ribbing for increased rigidity, which also houses electronic components and integrates air filter and fuel tank accommodations, using polyamide, polyethylene, or polypropylene with glass and carbon fibers, and simplified assembly with screw connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional aluminum or steel frameworks are used for motorcycle rear frames, then structural strength and rigidity are achieved, but production time is long, material costs are high, and assembly complexity increases

Engineering Contradiction:
Improvestructural strengthVSAvoidproduction time
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The patent changes the material parameter from traditional metals (aluminum or steel) to plastic through injection molding. This parameter change enables mass production with shorter cycle times while maintaining structural integrity through optimized plastic material selection and molding parameters

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical assembly process of metal frameworks with a single-step injection molding process. The complex assembly of multiple metal components is substituted by molding the complete rear frame structure in one operation, dramatically reducing production time and assembly complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If plastic materials are used for motorcycle rear frames, then production time is reduced and material costs decrease, but dimensional accuracy and structural rigidity may be compromised

Engineering Contradiction:
Improveproduction timeVSAvoiddimensional accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs composite plastic materials that combine base polymers with reinforcing fillers or fibers. This composite approach enhances dimensional stability and structural rigidity of the plastic rear frame while maintaining the production efficiency and cost advantages of plastic injection molding

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies local quality enhancement by optimizing material composition and molding parameters for specific regions of the rear frame. Critical structural areas receive enhanced material properties through localized reinforcement or adjusted molding conditions to ensure required dimensional accuracy

Inventive Principle:
Principle #3Local quality

3Strength

If traditional metal frameworks are used, then structural support is provided, but the number of components increases and assembly complexity increases

Engineering Contradiction:
Improvestructural supportVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges multiple separate structural components into a single integrated plastic rear frame structure. The injection molding process produces a unified component that combines functions previously requiring multiple metal parts, thereby reducing assembly complexity while maintaining structural support

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plastic rear frame is designed as a multi-functional universal structure that provides structural support, mounting points for various components, and integration of fluid passages. This universal design eliminates the need for separate specialized components, reducing overall assembly complexity

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

Data Source

PatentEP3022111B1Multifunctional rear motorcycle frame
Publication Date: 2017.09.06 BAYERISCHE MOTOREN WERKE AG
  • EP3022111B1 patent drawingFigure 1~2
  • EP3022111B1 patent drawingFigure 3~4
  • EP3022111B1 patent drawingFigure 5

AI summary

Disclosed is a rear frame (1) for a motorcycle, formed from two halves (2,3) consisting of a plastics material, said halves being produced in an injection-moulding method. When the halves are joined together they form a closed box section when viewed in cross-section.