Speed Control for Traveling Work Vehicle
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Solution Overview
Problem
Conventional speed control systems in traveling work vehicles fail to smoothly reduce vehicle speed to a desired level when the driver intends to slow down, as they require re-acceleration after neutralizing the continuously variable transmission mechanism, disrupting the driver's intended speed control experience.
Innovation Solution
A speed control device that incorporates a speed change device, a maximum speed definer, a target speed calculator, a vehicle speed controller, a braking device, and a forcible target speed modifier, allowing for smooth deceleration and speed adjustment by modifying the target speed based on driver input, aligning with the driver's intended speed reduction without re-acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the continuously variable transmission mechanism is put into neutral during braking, then braking ability is improved, but the vehicle cannot smoothly reduce speed to a desired speed without re-acceleration
Solution Approach 1:
The transmission mechanism dynamically adjusts the speed change ratio during braking based on vehicle speed and braking force, transitioning from a fixed neutral state to a variable ratio state that enables smooth speed reduction to a desired level without complete interruption of power transmission
Solution Approach 2:
The control unit changes the speed change ratio parameter during braking operation based on detected vehicle speed and braking force magnitude, allowing the transmission to adapt its ratio dynamically rather than being fixed in neutral, thereby enabling smooth speed reduction while maintaining braking effectiveness
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
Enables smooth deceleration and speed control that aligns with the driver's intentions, allowing for precise reduction in vehicle speed without the need for re-acceleration, enhancing the overall driving experience by maintaining consistent speed control.
Implementation Method 1
a hydrostatic continuously variable transmission mechanism
Data Source
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AI summary
A speed control device in a traveling work vehicle (1) changes a speed of rotational drive power from an engine to drive vehicle wheels and includes: a target speed calculator (62) determining a target speed, based on operation deflection of a speed change device (6B). A vehicle speed controller (67) adjusting a speed change ratio based on the target speed. A vehicle speed obtainer (6C) obtaining an actual vehicle speed. A forcible target speed modifier (63) forcibly modifying the target speed to a lower speed based on operation of a braking device (BD). A release (64) can treat an operation of the speed change device (6B) as a trigger to cancel the target speed forcibly modified by the forcible target speed modifier (63), and conforming the target speed to the actual vehicle speed.