Closed-Circuit Hydraulic Drive Venting With Gas-Liquid Separation
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Solution Overview
Problem
Existing closed-circuit hydraulic drive units with sealed tanks face challenges in efficiently removing air accumulated within the system, leading to potential air accumulation and reduced operational efficiency.
Innovation Solution
A closed-circuit hydraulic drive unit configuration that includes a sealed tank connected to supply-discharge lines, an air vent port, and a gas-liquid separator, allowing air to be discharged externally with hydraulic oil, and a tank support mechanism for easy maintenance and stress reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealed tank is used to store hydraulic oil, then the tank is protected from contamination and maintains system integrity, but air accumulated in the system cannot be effectively removed and becomes trapped in the sealed tank
Solution Approach 1:
The system is divided into separate functional zones: the sealed tank for oil storage and the pump casing with air vent port for air removal. This segmentation allows the tank to remain sealed while providing a dedicated pathway for air evacuation through the pump, resolving the contradiction between maintaining system integrity and removing harmful air accumulation.
Solution Approach 2:
The pump casing acts as an intermediary component between the sealed tank and the external environment. Air from the sealed system is transported through the pump casing to the air vent port, serving as a mediator that enables air removal without compromising the sealed nature of the hydraulic tank.
2Object-affected harmful factors
If the tank is configured as a sealed tank, then contamination is prevented, but air entering the tank accumulates and cannot be released
Solution Approach 1:
The air vent port extracts the harmful element (air) from the sealed system through the pump casing. This allows the tank to remain sealed for contamination prevention while providing an extraction pathway for air removal, resolving the contradiction between preventing contamination and eliminating air accumulation.
3Ease of operation
If the pump is disposed upward of the valve block and sealed tank, then air can be collected in the pump casing for easy removal, but the unit occupies more vertical space
Solution Approach 1:
The pump serves dual functions: hydraulic fluid delivery and air collection/ventilation. By combining the air removal function with the existing pump structure and positioning it vertically above the tank, the design achieves efficient air removal without adding separate dedicated air removal components, thereby minimizing the increase in vertical space.
4Object-generated harmful factors
If direction switching valves are installed in supply-discharge lines to remove air, then air can be vented from the closed circuit, but the unit configuration becomes complex
Solution Approach 1:
The pump is designed to perform multiple functions: hydraulic fluid pumping and air ventilation. The air vent port integrated into the pump casing allows the pump to serve as both the hydraulic power source and the air removal mechanism, eliminating the need for separate direction switching valves and simplifying the overall circuit configuration.
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
Facilitates the efficient removal of air from the system, improving operational efficiency and allowing for easy maintenance of the sealed tank without disassembling the unit's framework.
Implementation Method 1
a gas-liquid separator that separates air and the hydraulic oil flowing through the connecting line from each other
Implementation Method 2
a pump including a casing, a pair of pump ports
Implementation Method 3
a suction line that leads the hydraulic oil in the sealed tank to the pump
Data Source
Figure 1
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AI summary
An object is to make it possible to readily remove air from the inside of a closed-circuit type hydraulic drive unit. A hydraulic drive unit (1) includes: a pump (12); a pair of supply-discharge lines (13a, 13b); a valve block (40); a sealed tank (17); a suction line (24) that leads hydraulic oil in the sealed tank (17) to the pump (12); a connecting line (27) that connects an air vent port (12d) of the pump (12) to the suction line (24); and a gas-liquid separator (28) that separates air and the hydraulic oil flowing through the connecting line (27) from each other. The pump (12) is disposed upward of the valve block (40) and the sealed tank (17) in a vertical direction.