Excavator Priority Control via Electro-Proportional Valve
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Solution Overview
Problem
Existing priority function control apparatuses for construction machines face challenges in smoothly adjusting the extent of hydraulic fluid supply to optional devices and attachments due to load pressure differences, limiting the movement of attachments during combined operations, and lack an intuitive interface for operators to set preference levels based on varying load conditions.
Innovation Solution
A priority function control apparatus with a controller that outputs electrical control signals to an electro proportional reducing valve, allowing operators to set and adjust the priority of optional devices through a graphical interface, limiting hydraulic fluid supply based on detected load pressures and operation amounts, ensuring optimal attachment movement and coping with load changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hydraulic fluid supply to optional device is increased due to lower load pressure, then optional device operation is improved, but attachment movement becomes limited
Solution Approach 1:
The patent changes the pressure parameter by installing a pressure reducing valve in the signal line to the optional device spool. This valve reduces the signal pressure supplied to the optional device spool, thereby controlling the amount of hydraulic fluid supplied to the optional device, preventing it from taking all available hydraulic fluid and ensuring the attachment can move properly
Solution Approach 2:
The patent introduces a pressure reducing valve as an intermediary element in the hydraulic control system. This valve acts as a mediator between the hydraulic pump and the optional device spool, regulating the signal pressure and controlling the flow distribution to prevent the optional device from monopolizing hydraulic fluid supply
2Ease of operation
If fixed priority function is applied through orifice or pressure reducing valve, then attachment movement is protected, but ability to smoothly adjust hydraulic fluid supply based on load conditions is lost
Solution Approach 1:
The patent makes the priority function adjustable and dynamic by providing a control unit that allows operators to set different priority levels for the optional device. The pressure reducing valve's opening degree can be varied based on detected load pressure and operation amounts, enabling smooth adjustment of hydraulic fluid supply according to actual working conditions rather than being fixed
3Ease of operation
If priority function control is implemented, then attachment movement limitation is prevented, but operator interface for setting preference levels is lacking
Solution Approach 1:
The patent implements a control unit that detects load pressure and operation amounts, then automatically adjusts the priority function settings. The system provides feedback to the operator through the control unit, allowing preference levels to be set and adjusted based on actual operating conditions, making the complex control transparent to the operator
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 prevents attachment movement limitations and allows for efficient adjustment of hydraulic fluid supply, enhancing operability and work efficiency by enabling operators to set preference levels and adapt to changing load conditions during operations.
Implementation Method 1
an electro proportional reducing valve (10) which converts signal pressure input in accordance with an operation signal of an electrical operation device (9) for the optional device into secondary signal pressure corresponding to the operation signal
Implementation Method 2
due to a difference in load pressure between the optional device and the attachment, hydraulic fluid may not be smoothly supplied from a hydraulic pump to the optional device and the attachment
Data Source
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AI summary
A priority function control apparatus for a construction machine and a control method thereof are disclosed, which enable an operator to set the order of preference or the extent of preference of an optional device in the case where a work is done through replacement of the optional device attached to an excavator. The priority function control apparatus includes a hydraulic pump and a pilot pump; an optional device and an attachment connected to the hydraulic pump; an attachment operation lever outputting an operation signal when an operator performs an operation; an optional device spool controlling a flow direction of hydraulic fluid that is supplied from the hydraulic pump to the optional device; an attachment spool controlling an amount and a flow direction of the hydraulic fluid supplied from the hydraulic pump to the attachment; an electrical operation device for the optional device; an electro proportional reducing valve outputting secondary signal pressure that corresponds to the operation signal of the electrical operation device for the optional device; a first pressure detection sensor detecting in real time signal pressure depending on the operation amount of the attachment operation lever to output a detection signal; and a controller limiting the signal pressure that is applied from the electro proportional reducing valve to the optional device spool by the operation of the electrical operation device for the optional device to a preset signal pressure if a priority function is applied depending on the operation amount of the attachment through detection of the first pressure detection sensor.