Wheel Loader Transmission Kickdown Control via Boom Sensors
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Solution Overview
Problem
Existing automatic transmission control methods for wheel loaders delay the kickdown operation, leading to inefficiencies in operations like excavation, as there is a time gap between the start of the operation and the transmission adjustment, and fail to differentiate between loading and excavation operations accurately.
Innovation Solution
The method involves using a combination of boom and bucket angle sensors to provide bucket position and posture information to the transmission control unit, allowing for early kickdown from high to low gear based on predetermined conditions such as low load, slow speed, and bucket position, ensuring the kickdown occurs before the operation starts and avoiding it during loading operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmission control is performed based on detected transmission load increase during excavation operation, then the transmission can respond to load changes, but the kickdown operation is delayed and work efficiency deteriorates
Solution Approach 1:
The system performs preliminary action by detecting the start of excavation operation through sensors (boom angle sensor, bucket angle sensor, hydraulic pressure sensor) before the transmission load actually increases, and proactively commands the kickdown transmission in advance. This eliminates the time gap between operation start and transmission response, allowing the transmission to be already in the appropriate low gear when the excavation load begins, thereby improving work efficiency while maintaining reliable transmission control.
2Productivity
If kickdown transmission is performed based on slow travel speed and low transmission load, then early kickdown can be achieved, but unnecessary kickdown may occur during loading operation when wheel loader brakes
Solution Approach 1:
The system uses feedback by continuously monitoring multiple parameters including boom angle, bucket angle, hydraulic pressure, and travel speed to accurately determine the operational state. The transmission control unit integrates this feedback information to distinguish between excavation operation (where kickdown is needed) and loading operation with braking (where kickdown should be prevented). This multi-parameter feedback mechanism ensures accurate operation identification and prevents unnecessary kickdown while maintaining high work efficiency.
Data Source
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AI summary
The present invention relates to a method for automatically controlling a transmission of a wheel loader, and more particularly, to an automatic control method for allowing a kickdown to be automatically performed in a specific stage such as excavation operation among a plurality of operational stages in which the wheel loader performs operations, and to this end, the method includes: receiving, by a transmission control unit, various information from a sensor of a transmission; receiving, by the transmission control unit, bucket position information from a boom angle sensor; and performing an automatic kickdown transmission from shift stage 2 to shift stage 1 when the received information satisfies a predetermined condition, and when the wheel loader brakes for an excavation operation, an automatic kickdown transmission is performed according to conditions of low engine RPM, low load and low travel speed and a condition in which the position of a bucket is adjacent to the ground level, and accordingly, the excavation operation starts at the state where the transmission is shifted to the shift stage 1 in advance, thereby improving work efficiency.