Dual Pump Hydraulic System for Torque Transfer Control
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Solution Overview
Problem
Existing power transmission systems with torque transfer devices and limited slip differentials face challenges in controlling fluid delivery to their respective actuators in a simple and cost-effective manner, especially in four-wheel drive and all-wheel drive vehicle applications.
Innovation Solution
A hydraulic system with a single motor driving two pumps, where one pump supplies hydraulic fluid to a torque transfer device actuator and the other to a limited slip differential actuator, utilizing electronic clutches and a toroidal continuously variable transmission to regulate fluid pressure and torque transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single motor drives both torque transfer device and limited slip differential, then cost and complexity are reduced, but precise control of fluid delivery to each actuator becomes more difficult
Solution Approach 1:
The patent divides the hydraulic system into two separate pump circuits, each dedicated to one actuator (torque transfer device actuator and limited slip differential actuator). This segmentation allows independent control of fluid delivery to each actuator while both pumps are driven by a single motor, thus reducing overall system complexity while maintaining ease of operation.
Solution Approach 2:
The patent introduces electronic clutches as intermediary components between the single motor and the two pumps. These clutches act as mediators that can selectively engage or disengage power transmission to each pump, enabling precise control of fluid delivery to each actuator independently while both are driven by one motor.
2Ease of operation
If separate pumps are used for each actuator, then fluid delivery control is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges two pump functions into a single motor drive system. Instead of using two independent motors each driving one pump, the system combines both pumps on a single motor, reducing the number of prime movers and associated control systems while maintaining separate fluid delivery control through the use of electronic clutches.
Solution Approach 2:
The single motor is designed to perform multiple functions by driving both the first pump and the second pump through selective engagement of electronic clutches. This multi-functionality allows one motor to replace what would traditionally require two separate motors, reducing system complexity while maintaining independent control capabilities.
3Adaptability or versatility
If electronic clutches are added to control torque distribution, then adaptability and control precision are improved, but device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical clutch mechanisms with electronic clutches that can be controlled by electronic signals. This substitution provides more precise and adaptable control of torque distribution to the pumps while reducing mechanical complexity through the use of electronically controlled engagement and disengagement mechanisms.
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
Enables adaptive control of torque transfer and torque differentiation between wheels, improving the efficiency and cost-effectiveness of power transmission in four-wheel drive modes by precisely regulating clutch engagement forces through the hydraulic system.
Implementation Method 1
a first pump selectively supplies the hydraulic fluid to the first actuator
Implementation Method 2
a second pump selectively supplies the hydraulic fluid to the second actuator
Implementation Method 3
The first clutch according to one example is an electronic clutch
Data Source
AI summary
A hydraulic system for a vehicle drivetrain includes a torque transfer device having a first actuator that actuates to selectively communicate rotatable motion from an input member to an output member. A limited slip differential selectively transfers drive torque from the output member to at least one of the first and second axle shafts. A motor drives a first and a second output shaft. A first pump is rotatably driven by the first output shaft. The first pump selectively supplies the hydraulic fluid to the first actuator. A second pump is rotatably driven by the second output shaft. The second pump selectively supplies the hydraulic fluid to the second actuator.