Work Vehicle Gearshift Memory Control for Safe Speed Limiting
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Solution Overview
Problem
Existing work vehicles with continuously variable transmissions face issues where unintended speed changes occur due to automatic gearshift position reproduction, making it difficult for drivers to comprehend gearshift operations and travel control, leading to unsafe conditions.
Innovation Solution
A work vehicle with a transmission system that includes a memory switch to store gearshift positions, restrict higher-speed gearshifts, and display set speeds, ensuring safe travel by preventing unexpected speed increases and facilitating easy comprehension of gearshift operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the actuator automatically reproduces the stored gearshift position, then the gearshift position can be easily reproduced, but unintended speed increase or reduction occurs making it difficult for the driver to comprehend gearshift operations
Solution Approach 1:
The patent implements feedback by displaying the stored gearshift position on a display unit. This allows the driver to see what position is stored and understand the relationship between operation and reproduction, resolving the contradiction between easy reproduction and driver comprehension
Solution Approach 2:
The display unit acts as an intermediary between the automatic reproduction system and the driver. It provides visual information about the stored position, enabling the driver to comprehend the system's state without interfering with the automatic reproduction function
2Extent of automation
If the transmission is controlled irrespective of gearshift operation lever position, then automatic reproduction is achieved, but the driver experiences unintended speed changes
Solution Approach 1:
The patent applies preliminary anti-action by preventing storage of gearshift positions that would cause unsafe speed increases. The control unit checks whether the operated position is lower than the stored position before allowing storage, thereby preemptively avoiding unintended speed increases that would compromise safe travel
Solution Approach 2:
Instead of allowing automatic reproduction of any stored position, the system inverts the logic by restricting reproduction to only those positions that are lower than currently stored positions. This reversal prevents unsafe speed increases while maintaining automatic reproduction functionality
Data Source
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AI summary
The invention provides a work vehicle that allows easy comprehension of states of a gearshift operation and travel control and thus can travel safely. In the work vehicle that includes: a transmission (41) that shifts a gear stage on the basis of an operation of a gearshift operation tool (18, 23); and a memory switch (70) that detects an operation position of the gearshift operation tool (18, 23) and stores the operation position in a controller (100), when the operation position is stored by using the memory switch (70), a gearshift operation of the gearshift operation tool (18, 23) to a higher-speed side than the operation position stored by using the memory switch (70) is disabled, and the gearshift operation of the gearshift operation tool (18, 23) to a lower-speed side than the operation position stored by using the memory switch (70) is enabled.