Hydraulic Pump Flow Control for Industrial Vehicle Steering Kickback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing hydraulic pressure supply systems for industrial vehicles, such as fork-lift trucks, experience a time delay in valve spool displacement due to a reduction in flow area caused by an orifice, leading to a temporary shortage of pressurized working oil for the power steering device when the cargo handling device stops operation, resulting in kickback or sudden rotational resistance of the steering wheel.
Innovation Solution
A hydraulic pressure supply device with a programmable controller that adjusts the discharge flow rate of the hydraulic pump to prevent kickback by increasing the flow rate when the cargo handling device is in operation and decreasing it gradually when it stops, while ensuring the power steering device receives the required pressurized working oil, thereby avoiding a sudden decrease in oil supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the discharge flow rate of the hydraulic pump is decreased when the cargo handling device stops operation, then power consumption is reduced, but the working oil amount supplied to the power steering device temporarily falls into short supply causing kickback
Solution Approach 1:
The controller detects when the cargo handling device stops operation and delays the decrease in discharge flow rate of the hydraulic pump for a predetermined period. This preliminary delay ensures that the power steering device continues to receive sufficient working oil during the transition period, preventing kickback while eventually reducing power consumption.
2Reliability
If the priority flow rate control valve displaces the valve spool to increase distribution ratio to the power steering device, then steering oil supply is improved, but the time delay due to orifice causes temporary short supply before displacement completes
Solution Approach 1:
The controller anticipates the need for increased steering oil supply by detecting when the cargo handling device stops operation. It delays the reduction in pump discharge flow rate, providing a buffer period that allows the priority flow rate control valve to complete its spool displacement and increase the distribution ratio to the power steering device without causing temporary short supply.
3Productivity
If the controller lowers the rotation speed of the electric motor immediately when cargo handling stops, then energy efficiency is improved, but the discharge flow rate decrease causes kickback in the steering wheel
Solution Approach 1:
The controller implements a delayed response strategy where it detects the stop of the cargo handling device and maintains the current discharge flow rate for a predetermined delay period before reducing it. This preliminary maintenance of flow rate prevents kickback and ensures smooth steering operation, while still achieving energy efficiency ultimately by reducing the motor rotation speed after the delay.
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 prevents kickback by ensuring a stable supply of pressurized working oil to the power steering device, maintaining smooth operation of the steering wheel even when the cargo handling device stops, while optimizing electric motor rotation speed to minimize power consumption.
Implementation Method 1
a hydraulic pump 10 which discharges pressurized working oil
Implementation Method 2
a priority flow rate control valve 30 which distributes the pressurized working oil discharged by the hydraulic pump 10 to the power steering device 20 and the cargo handling device 19
Implementation Method 3
The hydraulic pump is driven by an electric motor
Data Source
AI summary
A priority flow rate control valve (30) distributes pressurized working oil discharged from a hydraulic pump (10) driven by an electric motor (11) to a power steering device (20) first, and distributes the residual pressurized working oil to a cargo handling device (19). The rotation speed of the electric motor (11) and the distribution ratio of the pressurized working oil of the priority flow rate control valve (30) vary depending on the operation states of these devices (19, 20). By decreasing the rotation speed of the electric motor (11) at a rate smaller than a normal decrease rate when the cargo handling device (2) stops operation in a state where the power steering device (20) and the cargo handling device (19) are in operation, a kickback in a steering wheel (7) due to a response delay of the priority flow rate control valve (30) can be prevented.