Wheel Loader Lift Cylinder Damping for Pitching Suppression
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Solution Overview
Problem
In work machines like wheel loaders, pitching of the vehicle body occurs regardless of speed, leading to potential load instability and falls from the work implement, as existing systems fail to effectively absorb forces transmitted from the work implement to the vehicle body.
Innovation Solution
A work machine equipped with a hydraulic cylinder, hydraulic circuit, accumulator, and controller that switches an on/off valve to open position when pitching is predicted, connecting the lift cylinders and accumulator to absorb vibrations and stabilize the vehicle body, thereby suppressing pitching across various speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the vehicle speed meets or exceeds a first threshold, then the lift cylinder and accumulator are interconnected to absorb force from the vehicle body, but when the vehicle speed is equal to or less than a second threshold, the lift cylinder and accumulator are disconnected to suppress reduction in loading performance
Solution Approach 1:
The system dynamically switches between connected and disconnected states of the lift cylinder and accumulator based on vehicle speed thresholds. The controller automatically adjusts the connection state to optimize both vehicle body stability during high-speed operation and loading performance during low-speed operation, resolving the contradiction between these two requirements.
2Productivity
If the lift cylinder and accumulator are disconnected at low vehicle speed to maintain loading performance, then loading performance is preserved, but the force transmitted from the work implement to the vehicle body cannot be absorbed, causing large pitching and potential load falls
Solution Approach 1:
The controller monitors vehicle speed and automatically adjusts the connection state of the lift cylinder and accumulator based on feedback from speed sensors. This closed-loop control ensures that the system responds appropriately to changing operating conditions, maintaining both loading performance and vehicle body stability under different speed conditions.
3Stability of the object's composition
If pitching suppression is prioritized by keeping the lift cylinder and accumulator connected regardless of vehicle speed, then vehicle body stability is improved, but loading performance deteriorates due to the disconnected state being necessary for optimal loading
Solution Approach 1:
The system changes the operational parameter (connection state) of the lift cylinder and accumulator based on the vehicle speed parameter. By adjusting this parameter dynamically, the system optimizes both vehicle body stability and loading performance for different operating conditions, resolving the contradiction between these two performance aspects.
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
The solution effectively suppresses vehicle body pitching and prevents load falls by proactively engaging the travel damper function based on predicted pitching conditions, ensuring stable operation regardless of vehicle speed.
Implementation Method 1
The accumulator is connected to the hydraulic circuit through an on/off valve. The controller is configured to switch the on/off valve to an open position when pitching is predicted to occur on the vehicle body.
Implementation Method 2
The hydraulic cylinder is configured to drive the work implement. The hydraulic circuit is connected to the hydraulic cylinder.
Data Source
AI summary
A wheel loader has a vehicle body, lift cylinders, a hydraulic circuit, an accumulator, and a controller. The vehicle body has a work implement. The lift cylinders drive the work implement. The hydraulic circuit is connected to the lift cylinders. The accumulator is connected to the hydraulic circuit through an on/off valve. The controller switches the on/off valve to the open position when pitching is predicted to occur on the vehicle body.