Work Vehicle Transmission Segmentation for Efficiency

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Solution Overview

Problem

Conventional work vehicles face challenges in increasing the output of hydromechanical transmissions without sacrificing power transmission efficiency, leading to increased manufacturing costs and reduced operability due to complex control systems and frictional forces during turning operations.

Innovation Solution

A work vehicle configuration that includes a driving force blocking mechanism to inhibit reverse rotation of traveling units, a control system that selects between instruction and measured values for optimal output, and a control section to manage the outputs of straight-traveling and turning systems, ensuring safe and stable operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the capacity of the hydromechanical transmission is increased to increase output, then the output is improved, but manufacturing costs increase and power transmission efficiency deteriorates

Engineering Contradiction:

Improveoutput of hydromechanical transmissionVSAvoidpower transmission efficiency

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The transmission system is segmented into two independent paths: a straight-traveling system using a hydromechanical transmission for efficient straight-line operation, and a turning system using a hydraulic stepless transmission for turning operations. This segmentation allows each subsystem to be optimized independently, preventing the need to increase overall transmission capacity for occasional turning needs while maintaining high power transmission efficiency during straight traveling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically switches between the straight-traveling system and turning system based on operational requirements. The control section activates the appropriate transmission path depending on whether the vehicle is traveling straight or turning, ensuring optimal power transmission efficiency is maintained during straight traveling while still providing adequate turning capability when needed.

Inventive Principle:

Principle #15Dynamics

2Power

If the capacity of the hydromechanical transmission is increased to increase output, then the output is improved, but device size and manufacturing costs increase

Engineering Contradiction:

Improveoutput of hydromechanical transmissionVSAvoidmanufacturing costs

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If a hydraulic stepless transmission is used for turning, then turning capability is improved, but frictional force during pivot turning causes unexpected operations

Engineering Contradiction:

Improveturning capabilityVSAvoidoperational stability during pivot turning

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The control section continuously monitors the operating state of the turning system and provides feedback control. When pivot turning is detected or when the left and right traveling units are subjected to frictional force in opposite directions, the control section adjusts the output of the turning system transmission path to prevent consecutive pivot turns and unexpected operations, thereby maintaining operational stability while preserving turning capability.

Inventive Principle:

Principle #23Feedback

4Adaptability or versatility

If the control system combines multiple signals for traveling operation, then control functionality is improved, but computation load increases and operability deteriorates

Engineering Contradiction:

Improvecontrol functionalityVSAvoidoperability

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The control system is segmented into separate control sections: a straight-traveling controller for the straight-traveling system and a turning controller for the turning system. Each controller manages its respective transmission path independently, simplifying the control logic and reducing computation load compared to a unified controller that would need to process all signals simultaneously. This segmentation maintains comprehensive control functionality while improving responsiveness and reducing complexity.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10926795B2Work vehicle

Publication Date: 2021.02.23 YANMAR POWER TECH CO LTD

AI summary

A work vehicle including: an engine mounted on a traveling body; a straight-traveling system transmission path including a first stepless transmission device; and a turning system transmission path including a second stepless transmission device. The work vehicle combines an output of the straight-traveling system transmission path and an output of the turning system transmission path to drive left and right traveling units. The work vehicle further includes: control sections that control the output of the straight-traveling system transmission path and the output of the turning system transmission path in cooperation with each other; and a driving force blocking mechanism that blocks a driving force transfer from the straight-traveling system transmission path. When the driving force transfer from the straight-traveling system transmission path is blocked by the driving force blocking mechanism, the mutually reverse rotation operations of the left and right traveling units is inhibited.