Unit Swing Power Unit Cylinder Offset Design

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional unit swing type power units for vehicles face challenges in compacting the engine body's vertical dimension and reducing loss horsepower due to the arrangement and construction of drive members and electric motors, which increase fuel consumption.

Innovation Solution

The power unit features a transmission casing with a continuously variable transmission mechanism and an engine body where the cylinder axis is offset relative to the crank axis, allowing the engine to swing, with support structures positioned to minimize vertical space and reduce bearing loads, and key components like the electric motor and balancer are strategically placed to optimize space and balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the drive member and electric motor are arranged in a conventional configuration, then the transmission mechanism can function properly, but the vertical dimension of the engine body becomes large

Engineering Contradiction:
Improvevertical dimension of engine bodyVSAvoidarrangement and construction of drive member
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent applies dimensional reconfiguration by changing the spatial arrangement of the cylinder body relative to the crankshaft. Specifically, the cylinder body is positioned such that the virtual plane including the cylinder axis and parallel to the crankshaft axis passes through a position displaced downward from the crankshaft axis. This dimensional shift allows the drive member and electric motor to be arranged in available spaces without increasing the vertical dimension of the engine body, thereby resolving the contradiction between compact vertical size and functional component arrangement.

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

Solution Approach 2:

The patent utilizes the swing capability of the engine body to dynamically adjust the position of the cylinder body. By allowing the engine body to swing, the system can optimize the spatial relationship between the cylinder body, crankshaft, and drive components during operation. This dynamic adjustment enables compact vertical dimensions while maintaining proper function of the drive member and electric motor throughout the swing range.

Inventive Principle:
Principle #15Dynamics

2Productivity

If the electric motor and drive member are included in the power unit, then the transmission can be controlled, but loss horsepower increases and fuel consumption worsens

Engineering Contradiction:
Improvefuel consumption efficiencyVSAvoidloss horsepower
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent optimizes the spatial parameters and positioning of the electric motor and drive member to minimize energy losses. By carefully selecting the displacement position of the cylinder body and arranging the electric motor in available spaces, the design reduces unnecessary friction, improves mechanical efficiency, and minimizes loss horsepower. This parameter optimization allows the power unit to maintain better fuel consumption efficiency despite including the electric motor for transmission control.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1741897B1Unit swing type power unit for a vehicle and vehicle
Publication Date: 2015.04.15 YAMAHA MOTOR CO LTD
  • EP1741897B1 patent drawingFigure 1
  • EP1741897B1 patent drawingFigure 2
  • EP1741897B1 patent drawingFigure 3

AI summary

The present invention relates to a unit swing type power unit for a vehicle, in particular a saddle-ride type vehicle, in which a transmission casing accommodating therein a continuously variable transmission mechanism with a V-belt wound around a drive side sheave and a driven side sheave, and an engine body having a cylinder body and a crankshaft defining a crank axis are joined integrally to be supported on a vehicle body frame to be able to swing, wherein the cylinder body is formed so that a virtual plane, which includes a cylinder axis and is in parallel to the crank axis, passes through a position displaced toward a side of the crank axis, and vehicle provided with said power unit.