Agricultural Work Vehicle HST Sensor Coupling for Shift Accuracy
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Solution Overview
Problem
Existing agricultural work vehicles face inaccuracies in controlling engine rotations due to manufacturing deviations and structural complexities in the connection between the HST pedal and swash plate control shaft, leading to dead sections and operational deviations that affect gear shifting accuracy.
Innovation Solution
The agricultural work vehicle incorporates a sensor unit directly coupled to the swash plate control shaft to detect its rotation, eliminating dead sections and reducing operational deviations, thereby improving the accuracy of engine rotation control in response to gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor unit detects the rotation of the HST pedal or the movement of the connection link, then the gear shifting can be controlled, but the detected value becomes inaccurate due to manufacturing deviation and structural complexity
Solution Approach 1:
The patent extracts the sensor detection function from the complex connection link structure and relocates it directly to the swash plate control shaft. By removing the intermediary connection link from the detection path, the system eliminates the sources of manufacturing deviation and structural complexity that caused measurement inaccuracies, while preserving the gear shifting control function.
Solution Approach 2:
The patent introduces a new intermediary mechanism - a detection member directly coupled to the swash plate control shaft - that serves as a more reliable mediator between the HST pedal operation and the sensor detection. This new intermediary eliminates the problematic connection link while maintaining the necessary mechanical coupling for accurate detection.
2Measurement precision
If the connection link connects the HST pedal and swash plate control shaft, then gear shifting can be transmitted, but dead section increases and small operations are not reflected
Solution Approach 1:
The patent removes the connection link from the detection path, extracting the source of dead section and operational deviation. By directly coupling the detection member to the swash plate control shaft, even minimal pedal operations are immediately and accurately reflected in the detected value, eliminating the dead section problem.
Solution Approach 2:
The patent implements preliminary direct coupling of the detection member to the swash plate control shaft before any operational deviation can occur. This pre-established direct connection ensures that all subsequent small operations are immediately captured without the need to exceed a dead section threshold.
3Reliability
If the operational force is transmitted through the connection link, then the HST pedal operation can be transmitted to the swash plate, but operational force is lost and deviation occurs
Solution Approach 1:
The patent extracts the problematic connection link from the operational force transmission path and replaces it with a direct coupling mechanism. This elimination of the intermediary connection link prevents operational force loss and deviation, ensuring reliable transmission from the HST pedal to the swash plate control shaft.
Solution Approach 2:
The patent merges the HST pedal, detection member, and swash plate control shaft into a more integrated assembly by directly coupling the detection member to the control shaft. This merging eliminates the separate connection link that caused force loss, creating a more reliable unified transmission path.
Data Source
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AI summary
The present invention relates to an agricultural work vehicle comprising: a vehicle body supporting an engine; a hydraulic transmission for changing speed with respect to the drive generated by the engine; an HST pedal which is connected to a swash plate control shaft of the hydraulic transmission and rotates the swash plate control shaft; a sensor unit which is directly coupled to the swash plate control shaft, and senses the rotation of the swash plate control shaft to acquire sensing values; and a control unit for controlling the rotation speed of the engine according to the sensing values.