Hydraulic Bypass Line for Four-Wheel-Drive Stability
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Solution Overview
Problem
The existing hydraulic four-wheel-drive working vehicles face issues with excessively high hydraulic pressure in the first and third hydraulic lines, leading to fluid leakage and instability, especially when encountering substantial loads during travel, such as climbing slopes, which results in a lack of pressurized fluid and potential air suction into the circuit.
Innovation Solution
Incorporating a variable displacement hydraulic pump and hydraulic motors, along with a bypass line equipped with an orifice, to redirect pressurized fluid from the first hydraulic line to the second hydraulic line, preventing excessive pressure and ensuring a consistent supply to the third hydraulic line, thereby enhancing travel stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a substantial load for travel is applied to one of the hydraulic motors positioned on an upstream side in the pressurized fluid flowing direction (e.g., climbing up a slope), then the hydraulic motor can drive the vehicle against the load, but the hydraulic pressure of the first hydraulic line or the third hydraulic line becomes excessively high, resulting in leakage of pressurized fluid
Solution Approach 1:
The bypass line with orifice is pre-configured in the hydraulic circuit to provide a pressure relief path before excessive pressure builds up. When the hydraulic pressure in the first hydraulic line exceeds the orifice threshold, pressurized fluid automatically flows through the bypass line to the second hydraulic line, preventing pressure buildup that would cause leakage and maintaining system reliability during high-load travel conditions
2Force
If the hydraulic pressure of the first hydraulic line is increased to drive the hydraulic motor against a substantial load, then the vehicle can climb slopes, but the pressurized fluid leaks from the first hydraulic line and/or the first hydraulic motor
Solution Approach 1:
The bypass line with orifice provides a preventive pressure relief mechanism that activates before leakage occurs. When hydraulic pressure rises due to climbing loads, the bypass line diverts excess pressurized fluid to the second hydraulic line, maintaining pressure within safe operating limits and preventing fluid leakage from seals and connections in the first hydraulic line and first hydraulic motor
3Force
If the pressurized fluid leaks from the first hydraulic line and/or the first hydraulic motor, then the hydraulic motor can drive against load, but the amount of pressurized fluid discharged from the second hydraulic motor is reduced, causing lack of pressurized fluid in the third hydraulic line
Solution Approach 1:
The bypass line acts as an intermediary fluid transfer path that redirects pressurized fluid from the first hydraulic line to the second hydraulic line. This ensures that sufficient pressurized fluid reaches the second hydraulic motor and maintains adequate fluid quantity in the third hydraulic line, preventing fluid shortage and air suction even when the first hydraulic motor is working hard against substantial loads
4Force
If the pressurized fluid supply to the third hydraulic line becomes insufficient, then the hydraulic circuit can operate under load, but air is suctioned into the closed circuit, leading to unstable four-wheel-drive condition
Solution Approach 1:
The bypass line serves as a compensatory fluid supply pathway that ensures continuous pressurized fluid circulation in the closed hydraulic circuit. By redirecting fluid from the first to the second hydraulic line, it maintains adequate fluid levels in the third hydraulic line, preventing air suction and ensuring stable four-wheel-drive operation even during high-load conditions
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 effectively manages hydraulic pressure and fluid supply, preventing leakage and air suction, ensuring stable four-wheel-drive operation even under heavy loads, thus improving the overall travel stability of the vehicle.
Implementation Method 1
a first bypass line that causes at least a part of pressurized fluid in the first hydraulic line to bypass the hydraulic motor of the first hydraulic motor unit to be supplied to the second hydraulic line, the first bypass line having an orifice inserted therein
Data Source
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AI summary
A hydraulic four-wheel-drive working vehicle 1 includes a hydraulic pump 420, a first hydraulic motor unit 50 having a first hydraulic motor main body 120 and a second hydraulic motor unit 100E having a second hydraulic motor main body 620. A closed circuit a first hydraulic line for sending pressurized fluid discharged from the hydraulic pump 420 to the first hydraulic motor main body 120 at a forward movement of the vehicle, a second hydraulic line for sending pressurized fluid discharged from the first hydraulic motor main body to the second hydraulic motor main body at the forward movement of the vehicle, and a third hydraulic line for sending pressurized fluid discharged from the second hydraulic motor main body 620 to the hydraulic pump 420 at the forward movement of the vehicle. The closed circuit includes a first bypass line 810 that causes at least a part of pressurized fluid in the first hydraulic line to bypass the first hydraulic motor main body to be supplied to the second hydraulic line. The first bypass line 810 has an orifice 820 inserted therein, and preferably has also a check valve 830 inserted therein, the check valve preventing pressurized fluid from being flown from the second hydraulic line to the first hydraulic line.