Forklift Work Lever Lowering Control with Load-Adaptive Valve Tuning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional forklifts face challenges in controlling the lowering speed of the work lever, which varies with load weight due to hydraulic system characteristics, leading to instability, shocks, and degraded operability.
Innovation Solution
A system using a weight sensor to measure load weight, convert it to a voltage, and control the hydraulic motor and solenoid valve with a controller to achieve a constant lowering speed, independent of load weight, without a flow regulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a flow regulator is used to limit maximum lowering speed, then the maximum speed can be adjusted, but the amount of change in lowering speed varies depending on load weight, degrading controllability
Solution Approach 1:
The patent applies dynamics by making the flow regulator's valve opening area variable based on load weight. The controller dynamically adjusts the valve opening area according to the detected load weight, enabling the system to adapt to different loading conditions and maintain consistent lowering speed characteristics regardless of whether the forklift is loaded or unloaded.
Solution Approach 2:
The patent changes the parameter of valve opening area based on load weight. By detecting load weight and corresponding the valve opening area to a predetermined value, the system modifies the flow rate parameter dynamically, ensuring that the amount of change in lowering speed remains substantially constant across different load conditions.
2Speed
If conventional flow control is used, then maximum speed can be limited, but sudden changes in lowering speed cause shocks and vibrations, degrading system stability
Solution Approach 1:
The patent applies preliminary action by pre-establishing a correspondence between load weight and valve opening area values before operation. The controller refers to this predetermined correspondence to adjust the valve opening area, ensuring smooth and controlled speed changes that prevent sudden shocks and vibrations in the hydraulic system.
3Reliability
If load-dependent speed variation occurs, then hydraulic system characteristics are maintained, but operability is degraded as workers must operate differently depending on load weight
Solution Approach 1:
The patent applies feedback by using a load weight detector to continuously monitor the actual load weight and feeding this information back to the controller. The controller then adjusts the valve opening area based on the detected load weight, creating a closed-loop control system that automatically compensates for load variations and maintains consistent operability.
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
Ensures a consistent lowering speed change, enhancing forklift stability and operability while reducing costs by eliminating the need for expensive flow regulators.
Implementation Method 1
a weight sensor provided at one side of the work lever, the weight sensor measuring a weight of a load placed on the work lever and transmitting the measured value to a controller
Implementation Method 2
a hydraulic motor connected to the work lever through a hydraulic line to transmit a power to the work lever
Implementation Method 3
an electronic solenoid valve for controlling the hydraulic motor connected to the work lever
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present disclosure relates to a system of controlling a lowering speed of a work lever of a forklift which may realize a constant amount of change in the lowering speed of the work lever with respect to a valve opening area, irrespective of a weight of a load placed on the work lever, although a flow regulator is not provided. The system for controlling the lowering speed of a work lever of a forklift includes, a hydraulic motor (130) connected to the work lever through a hydraulic line to transmit a power to the work lever; an electronic solenoid valve (150) for controlling the hydraulic motor connected to the work lever; a weight sensor (140) provided at one side of the work lever, the weight sensor measuring a weight of a load placed on the work lever and transmitting the measured value to a controller (120); and said controller (120) arranged for controlling an RPM of the hydraulic motor (130) and a current amount of the electronic solenoid valve based on the measured value transmitted from the weight sensor (140).