Two-Rear-Wheel Electric Vehicle Frame Weight Reduction

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Solution Overview

Problem

Two-rear-wheel electric vehicles face challenges in reducing vehicle body weight while maintaining battery capacity, leading to increased power consumption and decreased convenience due to the need for more frequent charging and heavier handling.

Innovation Solution

The configuration includes a front support part at the bottom of the vehicle body frame to reduce bending loads, a rear inclined battery support, and a swing axis positioned rearward of the front support part and below the battery support, which lessens the load on the vehicle frame and allows for a larger battery capacity without increasing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If battery capacity is increased to reduce charging frequency, then power source capability is improved, but vehicle body weight increases

Engineering Contradiction:
Improvebattery capacityVSAvoidvehicle body weight
Core Design Contradiction:
Duration of action of moving objectVSWeight of moving object

Solution Approach 1:

The patent positions the battery in the rear inclined portion of the vehicle body frame, utilizing the spatial dimension created by the inclined structure. This allows the battery to be placed in an otherwise underutilized space region, increasing battery capacity without proportionally increasing overall vehicle body weight.

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

Solution Approach 2:

The patent creates a specific rear inclined portion with a battery support part designed exclusively for battery placement. This localized structural modification allows optimal battery positioning and weight distribution without requiring reinforcement of the entire vehicle body frame, thus avoiding unnecessary weight increase.

Inventive Principle:
Principle #3Local quality

2Strength

If vehicle body frame strength is increased to support heavier battery, then structural integrity is improved, but vehicle body weight increases

Engineering Contradiction:
Improvevehicle body frame strengthVSAvoidvehicle body weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent divides the vehicle body frame into distinct functional portions: a bottom portion supporting the shock absorber and a separate rear inclined portion with battery support. This segmentation allows the battery to be supported by a dedicated localized structure rather than requiring the entire frame to be strengthened, minimizing overall weight increase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rear inclined portion extends in a direction oblique to the vertical direction, creating a three-dimensional spatial arrangement. This angular configuration allows the battery support structure to leverage geometric distribution of forces, providing necessary structural strength without requiring excessive material and weight.

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

3Force

If shock absorber mounting position is optimized to reduce bending load, then structural load is reduced, but vehicle stability may be affected

Engineering Contradiction:
Improvebending load on vehicle body frameVSAvoidvehicle stability
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

The patent positions the shock absorber asymmetrically by mounting its front end portion on the bottom portion of the vehicle body frame at a location forward of the swing shaft. This asymmetric positioning creates a favorable force distribution that reduces bending loads on the frame while the rear inclined portion with battery provides counterbalancing stability.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The bottom portion of the vehicle body frame acts as an intermediary structure between the shock absorber and the rest of the frame. By providing a dedicated mounting location on the bottom portion, the patent creates a localized force transmission path that reduces bending moments on the main frame structure while maintaining overall vehicle stability through the combined system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration achieves a weight reduction of the vehicle body while ensuring battery capacity, reducing power consumption and improving handling and convenience by minimizing the frequency of charging.

Implementation Method 1

a shock absorber for lessening an impact that the pair of right and left rear wheels receives from a road surface

Methodology Applied
Scientific EffectImpact Force: Impact Force

Implementation Method 2

a shock absorber for lessening an impact

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2765070B1Two-rear-wheel electric-powered vehicle
Publication Date: 2016.02.03 YAMAHA MOTOR CO LTD
  • EP2765070B1 patent drawingFigure 1
  • EP2765070B1 patent drawingFigure 2
  • EP2765070B1 patent drawingFigure 3

AI summary

Provided is a two-rear-wheel electric vehicle that achieves a weight reduction of a vehicle body with ensuring of a battery capacity. A two-rear-wheel electric vehicle configured to lean its vehicle body frame when turning includes a vehicle body frame (3), a pair of right and left rear arms (31L, 31R), a battery (25, 71, 72), and a shock absorber (61). The vehicle body frame includes a head pipe (5), a front inclined portion (6), a bottom portion (7), and a rear inclined portion (8). The front inclined portion extends obliquely downward and rearward from the head pipe. The bottom portion includes a front support part (A3) that supports a front end portion of the shock absorber. The bottom portion extends rearward in a front-back direction of the vehicle from a rear end portion of the front inclined portion. The rear inclined portion includes a battery support part (27), and extends obliquely upward and rearward from a rear end portion of the bottom portion. A swing shaft (A1) is positioned rearward of the front support part and below the battery support part.