Hydraulic Damping Control for Forklift Mast Deflection
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Solution Overview
Problem
High-lift industrial truck lifting masts experience significant deflections and vibrations during operation, particularly when stacking or unstacking high racks, which existing damping technologies struggle to effectively mitigate, leading to inefficient energy consumption and suboptimal operational performance.
Innovation Solution
A method for operating a hydraulic damping device that involves measuring mast deflections and using a control device to generate an actuating signal for an electric motor to drive a hydraulic pump at a minimum speed, ensuring early activation and overcoming static friction forces to achieve faster damping responses, thereby reducing the time delay in damping operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the electric motor is activated only when needed for damping operations, then energy consumption is reduced, but time delay occurs due to startup from rest
Solution Approach 1:
The electric motor is activated in advance at minimum speed before damping operations are actually needed. This preliminary activation ensures the motor is already running and can immediately provide full damping capability when required, eliminating startup delays while minimizing energy consumption by keeping the motor at low speed during idle periods.
2Reliability
If the hydraulic pump operates from rest when damping is needed, then energy consumption is minimized, but static friction forces cause delayed response
Solution Approach 1:
The hydraulic pump is pre-activated at minimum speed before damping operations commence. This ensures the hydraulic system is already pressurized and ready to respond immediately when damping is required, overcoming static friction forces without energy loss from cold starts, while maintaining energy efficiency through minimum speed operation during idle periods.
3Reliability
If the hydraulic cylinder moves at speed proportional to deflection, then damping effectiveness is improved, but time delay occurs in converting operator input to cylinder speed
Solution Approach 1:
The hydraulic cylinder is kept in a pre-charged state with minimum speed operation before damping events occur. When operator input is detected, the system can immediately transition to the required damping speed without the delay of building pressure or overcoming static friction, ensuring both effectiveness and rapid response.
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
This approach allows for quicker reaction times and reduced energy consumption by pre-activating the electric motor and maintaining pressure in hydraulic elements, ensuring efficient damping of mast vibrations and deflections, even before the actual damping operation begins.
Implementation Method 1
a hydraulic pump (22) which delivers a hydraulic medium to a hydraulic cylinder (23)
Implementation Method 2
the amount of hydraulic medium delivered by a pump is set by specifying a speed for a driving electric motor
Implementation Method 3
a control device (18) determines an actuating signal for an electric motor (21) of the damping device which drives a hydraulic pump (22)
Implementation Method 4
how large the volume flow flowing into the hydraulic cylinder is in order to dampen deflections of the lifting mast
Data Source
Figure 1a~1
AI summary
Method for operating a hydraulic damping device for a lifting mast of a forklift truck, in which deflections of the lifting mast are measured and the measured values are fed into a control device for the damping device, and the control device generates control signals for an electric motor driving a hydraulic pump according to the measured values, in which furthermore one or more different operating parameters of the operation of the lifting mast are stored in the control device, from which an imminent or immediately imminent deflection of the mast operation can be derived, and the control device generates an advance signal according to the operating parameters to generate a control signal for the electric motor such that the electric motor is started up at a minimum speed.