Working Vehicle Gearshift Restraint for Stable Travel

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Solution Overview

Problem

Existing working vehicles experience instability during speed changes due to the time required to connect the shifter, leading to potential loss of stable travel.

Innovation Solution

A working vehicle equipped with a speed change restraint unit that detects an increase in speed exceeding a threshold, stopping the speed change process and reversing the transmission device's speed stage to maintain stability, utilizing a solenoid valve and control device to manage hydraulic fluid for efficient linkage member movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the shifter is allowed to engage with a rotating body to achieve speed change, then speed change can be achieved, but it takes time to connect the shifter making the working vehicle unable to travel in a stable manner

Engineering Contradiction:
Improvespeed change capabilityVSAvoidtravel stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The control unit detects the operator's speed change operation and initiates the speed change process in advance by controlling the shift fork to move the shifter. The system proactively manages the engagement process between the shifter and rotating body, monitoring vehicle speed throughout the transition to ensure stability is maintained during the speed change operation.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If the shifter connection time is reduced for stable travel, then travel stability is improved, but the mechanism becomes more complex requiring control units and detection devices

Engineering Contradiction:
Improvetravel stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control unit continuously detects vehicle speed during the speed change process and uses this feedback to determine whether to continue or cancel the speed change operation. When vehicle speed increases beyond acceptable thresholds during shifter engagement, the control unit automatically cancels the operation and returns the shifter to its original position, preventing instability without requiring overly complex control mechanisms.

Inventive Principle:
Principle #23Feedback

3Stability of the object's composition

If the speed change process is stopped when vehicle speed increases, then travel stability is maintained, but the speed change operation cannot be completed

Engineering Contradiction:
Improvetravel stabilityVSAvoidspeed change efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The control unit monitors vehicle speed throughout the speed change process and prepares to cancel the operation if speed increases beyond the threshold. This preliminary protective measure prevents instability before it can occur. The system balances safety and efficiency by only canceling the operation when necessary, allowing most speed change operations to complete successfully while maintaining travel stability.

Inventive Principle:
Principle #9Preliminary anti-action

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 solution ensures stable travel by canceling the speed change process when vehicle speed increases, preventing instability and maintaining the original speed stage, thus enhancing operational stability during speed adjustments.

Implementation Method 1

a solenoid valve configured to shift the movement mechanism to the stop position, the one position, or the other position using hydraulic fluid

Methodology Applied
Scientific EffectHydraulic fluid pressure: Hydraulic Press

Data Source

PatentEP3985284B1Working vehicle
Publication Date: 2023.05.10 KUBOTA CORP
  • EP3985284B1 patent drawingFigure 1
  • EP3985284B1 patent drawingFigure 2
  • EP3985284B1 patent drawingFigure 3

AI summary

A working vehicle (1) comprises: a vehicle body (3); a linkage device (4) configured to link a working device (2) to the vehicle body (3); a prime mover (8) provided on the vehicle body (3); a traveling device (7) configured to cause the vehicle body (3) to travel; a transmission device (5) configured to transmit power from the prime mover (8) to the traveling device (7) and perform a speed change process to change a speed of the vehicle body (3); an increase-in-speed detection device (96) configured to detect an increase in speed of the vehicle body (3); and a speed change restraint unit (90) configured such that, during the speed change process performed by the transmission device (5), when the increase in speed detected by the increase-in-speed detection device (96) has become equal to or greater than a threshold, the speed change restraint unit (90) stops the speed change process performed by the transmission device (5).