Wheel Loader Transmission Control for Smooth Loading Speed Reduction
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Solution Overview
Problem
Wheel loaders with torque converter type traveling drive systems face issues with clutch wear and operator discomfort due to frequent shifting between speed stages during loading operations, leading to inefficient speed control without using the brake.
Innovation Solution
A wheel loader equipped with a controller that adjusts gear ratios using solenoid control valves to automatically decrease vehicle speed during loading operations, selecting an intermediate gear ratio between the first and second speed stages based on detected traveling and lift arm operation states, allowing smooth speed control without operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the modulation clutch is slid to decrease vehicle speed during loading operation, then vehicle speed can be suppressed without brake usage, but the modulation clutch is easily worn and durability is reduced
Solution Approach 1:
The patent introduces a controller as an intermediary that automatically manages transmission speed stage selection based on sensor inputs. The controller mediates between the loading operation detection and transmission control, selecting appropriate speed stages without requiring manual operator intervention or excessive clutch sliding, thereby protecting the modulation clutch from wear while maintaining speed control.
Solution Approach 2:
The system implements feedback by using sensors to detect loading operation states and vehicle speed, then feeding this information back to the controller. The controller continuously monitors the modulation clutch's engagement state and adjusts transmission speed stage selection accordingly, preventing excessive clutch sliding and wear through closed-loop control.
2Speed
If the speed stage is shifted from second speed stage to first speed stage during loading operation, then vehicle speed is reduced without brake usage, but the vehicle speed becomes too slow and the operator feels discomfort due to large difference between speed stages
Solution Approach 1:
The patent applies dynamics by enabling dynamic, automatic selection of transmission speed stages based on real-time loading operation detection. Instead of fixed manual shifting, the controller dynamically adjusts speed stage selection according to the detected loading state, optimizing vehicle speed for both loading efficiency and operator comfort without requiring manual intervention.
Solution Approach 2:
The system implements self-service through automatic transmission control. The controller autonomously detects loading operations via sensors and automatically selects appropriate speed stages without operator intervention. This self-managing system eliminates the need for operators to manually shift gears or coordinate brake usage, reducing discomfort while maintaining optimal speed for loading operations.
3Speed
If manual speed control is performed by operator intervention during loading operation, then vehicle speed can be adjusted, but additional operational complexity and potential for error increases
Solution Approach 1:
The patent implements self-service by enabling the transmission system to automatically manage its own speed stage selection based on sensor-detected loading operations. The controller autonomously determines when loading operations are occurring and selects appropriate speed stages without requiring operator knowledge or manual intervention, simplifying the control interface while maintaining optimal performance.
Solution Approach 2:
The system uses feedback from sensors that detect loading operation states to automatically adjust transmission speed stages. This closed-loop control eliminates the need for manual speed control by operators, as the system continuously monitors its own operational state and makes appropriate adjustments autonomously, reducing control complexity and potential for human error.
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 automatic reduction of vehicle speed during loading without operator discomfort, reducing clutch wear and improving operational efficiency by minimizing brake usage and shifting discomfort.
Implementation Method 1
a torque converter configured to amplify torque transmitted from the engine
Implementation Method 2
a transmission configured to control a combination of a plurality of gears by means of a plurality of solenoid control valves
Data Source
AI summary
Provided is a wheel loader capable of automatically decreasing vehicle speed without making an operator feel discomfort during a loading operation. A wheel loader 1 mounted with a torque converter type traveling drive system comprises a controller 5 configured to control shifting of a transmission 32. When a vehicle body travels forward at vehicle speed corresponding to a second speed stage set greater by one speed stage than the lowest speed stage of the transmission 32 while operating the lift arm 21 upwardly, the controller 5 sets, as a gear ratio of the transmission 32, an intermediate gear ratio between a gear ratio corresponding to the second speed stage and a gear ratio corresponding to a first speed stage, and outputs a signal for selecting a combination of a plurality of gears corresponding to the set gear ratio to each first to fifth solenoid control valves 32A to 32E.