Hydraulic Drivetrain Flow Divider Layout for Turning Traction
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Solution Overview
Problem
Conventional hydraulic traction systems in utility vehicles suffer from inefficiencies and traction loss during turns due to equal fluid flow distribution to front and rear wheels, leading to speed differentials and wheel slippage, as they fail to adapt to varying steer angles and wheel speeds.
Innovation Solution
A closed loop hydraulic system with flow divider-combiner assemblies that distribute and recombine fluid flow to diagonally arranged hydraulic motors, allowing controlled speed variations and maintaining traction by adjusting flow splits based on wheel conditions, preventing overspeed and runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If equal fluid flow is distributed to front and rear wheels in conventional hydraulic systems, then the system structure is simple, but wheel speed differentials occur during turns causing traction loss and slippage
Solution Approach 1:
The hydraulic system is segmented into multiple independent circuits, with each wheel having its own hydraulic motor and flow control. This allows each wheel to receive independently controlled fluid flow, enabling different wheel speeds during turns while maintaining simple individual circuit designs
Solution Approach 2:
The system dynamically adjusts fluid flow distribution to each wheel based on steering angle and wheel position. During turns, the outer wheels receive higher flow rates than inner wheels, automatically adapting to the kinematic requirements of turning motion and preventing traction loss
2Productivity
If hydraulic motors are arranged in conventional front-rear configuration, then the hydraulic circuit is simple, but speed differentials during turns cause wheel slippage and reduced efficiency
Solution Approach 1:
The system employs asymmetric flow distribution where left and right wheels receive different fluid flow rates during turns. The hydraulic circuit is designed with asymmetric path lengths and flow resistance characteristics that automatically compensate for the different speeds required by outer and inner wheels, eliminating slippage and improving efficiency
Solution Approach 2:
The hydraulic system incorporates feedback mechanisms that respond to steering input and wheel speed differences. Flow divider-combiner assemblies automatically adjust fluid distribution based on the kinematic state of the vehicle, ensuring optimal flow rates to each wheel without requiring complex electronic control systems
3Power
If equal flow rates are supplied to all wheels, then the hydraulic pump operates at constant load, but wheel speed differentials increase drive pressure requirements and engine load during turns
Solution Approach 1:
The system changes the flow rate parameter supplied to each hydraulic motor based on wheel position and steering angle. During turns, the pump dynamically adjusts flow distribution parameters, supplying higher flow to outer wheels and lower flow to inner wheels, which reduces the peak pressure requirements and decreases engine load while maintaining simple hydraulic operation
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 significantly reduces drive pressure and wheel speed differentials during turns, enhancing traction and efficiency, allowing for more uniform torque distribution and reduced engine load, which can lead to cost and fuel economy benefits.
Implementation Method 1
A first flow divider-combiner assembly with a first port fluidly connected to the pump, a second port fluidly connected to the first and third hydraulic motors, and a third port fluidly connected to the second and fourth hydraulic motors
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A vehicle and a hydraulic propulsion system for the vehicle are provided with first and second motors diagonally arranged relative to one another on the vehicle, and third and fourth motors diagonally arranged relative to one another on the vehicle. First, second and third flow divider combiner assemblies are provided and are arranged in a closed fluid loop with the motors. A first port of each of the assemblies are fluidly connected to one another. The first assembly has a second port fluidly coupled to the first and second motors, and a third port fluidly coupled to the third and fourth motors. The second assembly has second and third ports fluidly coupled to the first and third motors, respectively. The third assembly has second and third ports fluidly coupled to the second and fourth motors, respectively. A method of controlling the hydraulic system is also provided.