Boom Hydraulic Circuit With Float Valve for Controlled Descent
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Solution Overview
Problem
Existing hydraulic systems for working machines, such as slew excavators, face inefficiencies when moving booms in ascending and descending directions due to varying hydraulic fluid flow requirements, leading to reduced efficiency and safety concerns.
Innovation Solution
A hydraulic system with two pumps and directional control valves that allow for efficient flow management by isolating chambers during descending movements and connecting them to a reservoir during ascending movements, incorporating a float state to enable free movement and pressure regulation, reducing the number of valves required and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a hydraulic fluid flow rate suitable for moving the boom in the ascending direction at an acceptable speed is provided, then the boom can ascend at an acceptable speed, but the boom would descend too quickly creating safety risks
Solution Approach 1:
The system dynamically adjusts the hydraulic circuit configuration based on boom movement direction. During ascending movement, the full pump capacity is directed to the head side chamber for fast ascent. During descending movement, the circuit is reconfigured to control fluid flow from the head side chamber, preventing uncontrolled descent. This dynamic reconfiguration resolves the contradiction between achieving high ascending speed and ensuring descending safety.
2Reliability
If a hydraulic pump operates at reduced capacity when moving the boom in the descending direction, then safety is improved, but the hydraulic system efficiency is reduced
Solution Approach 1:
During boom descent, the system utilizes the pump's own discharge line to supply hydraulic fluid to the rod side chamber, rather than requiring a separate control circuit. This self-service approach allows the pump to maintain near-maximum capacity operation while still providing controlled descent, thereby maintaining hydraulic system efficiency while ensuring safety.
3Speed
If the rod side chamber has a smaller volume for receiving hydraulic fluid, then the boom can descend quickly, but the boom would descend too quickly creating safety risks
Solution Approach 1:
The invention introduces an intermediary control mechanism in the form of a specially configured directional control valve that mediates the fluid flow between the pump and the rod side chamber. This intermediary device regulates the hydraulic fluid flow rate into the smaller volume rod side chamber, preventing uncontrolled rapid descent while still allowing reasonably fast descending speed, thus resolving the safety concern.
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 configuration improves efficiency by allowing pumps to operate near maximum capacity while ensuring safe and controlled boom movement in both directions, reducing the risk of accidents and equipment damage.
Implementation Method 1
a first ascending state of the first directional control valve configured to direct hydraulic fluid from the first pump to the ascending chamber to move the boom in the ascending direction
Implementation Method 2
a descending state of the first directional control valve configured to direct hydraulic fluid from the first pump to the descending chamber to move the boom actuator in the descending direction
Implementation Method 3
a float state of the second directional control valve configured to connect at least one of the ascending and descending chambers to the hydraulic reservoir for permitting the boom to move freely in the descending and/or ascending directions
Implementation Method 4
In addition, gravity assists with movement of the boom in the descending direction
Data Source
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AI summary
A hydraulic system for a working machine, the hydraulic system comprising: a hydraulic fluid reservoir; a boom actuator having an ascending chamber and a descending chamber; a first pump; a first directional control valve comprising a first ascending state configured for moving the boom in the ascending direction, a descending state configured for moving the boom actuator in the descending direction, and a first neutral state; a second pump; a second directional control valve comprising a second ascending state configured for moving the boom actuator in the ascending direction, and a second neutral state; wherein the second directional control valve further comprises a float state configured to connect at least one of the ascending and descending chambers to the hydraulic reservoir for permitting the boom to move freely in the descending and/or descending directions.