Hydraulic Controller Intermittent Pump Operation for Clutch Torque Linearity
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Solution Overview
Problem
Conventional hydraulic controllers for four-wheel drive vehicles require constant operation of electric oil pumps to maintain clutch engagement pressure, leading to motor durability issues and non-linear torque characteristics due to hysteresis, which complicates the hardware configuration and increases costs.
Innovation Solution
A hydraulic controller with a charging-type hydraulic circuit that allows intermittent operation of the oil pump by using a piston chamber with 1st and 2nd characteristics for pressurization and depressurization, controlled by an opening and closing valve, reducing motor operation and improving torque accuracy through staged pressure regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric oil pump operates constantly to maintain clutch engagement pressure, then the clutch engagement pressure is stable, but the motor durability deteriorates due to brush abrasion
Solution Approach 1:
The patent applies periodic action by controlling the electric oil pump to operate intermittently rather than continuously. The pump is activated only when hydraulic pressure falls below a threshold value, creating a periodic on-off operation pattern that reduces motor wear while maintaining adequate clutch engagement pressure through pressure feedback control
2Duration of action of stationary object
If the electric oil pump is operated intermittently to reduce motor wear, then the motor durability is improved, but the clutch engagement pressure stability deteriorates
Solution Approach 1:
The patent implements feedback control by continuously monitoring the hydraulic pressure in the clutch chamber and using this information to control the pump operation. When pressure drops below a predetermined threshold, the pump is activated to restore pressure, creating a closed-loop control system that maintains stable clutch engagement pressure despite intermittent pump operation
3Manufacturing precision
If the clutch torque characteristics are improved by changing hardware configuration such as clutch plate shape, then the linear characteristics of clutch torque are improved, but the product cost and structural complexity increase
Solution Approach 1:
The patent applies parameter changes by controlling the hydraulic pressure supplied to the clutch piston rather than modifying the physical structure of the clutch plates. By adjusting the pressure parameter through intermittent pump operation and feedback control, the system achieves improved torque characteristics without changing the mechanical design of clutch components
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 reduces motor wear by intermittent operation and enhances torque accuracy by achieving linear torque characteristics, simplifying the control system and reducing hardware complexity while maintaining engagement pressure.
Implementation Method 1
a piston chamber (15) to generate hydraulic pressure for a piston (12) that presses and engages the friction materials (13)
Implementation Method 2
hydraulic fluid charging valves (39, 53) for containing the hydraulic fluid in the oil passage (49)
Data Source
AI summary
In a hydraulic controller of driving force distribution device, including: a hydraulic circuit composed of an oil pump for supplying hydraulic fluid to a piston chamber of a clutch (or a driving force distribution device), an opening and closing valve installed in an oil passage between a check valve and the piston chamber, and an accumulator communicating to the piston chamber; control is performed so that the piston chamber reaches a target hydraulic pressure based on the 1st characteristic by closing the opening and closing valve and driving the oil pump at the time of pressurizing the piston chamber; and control is performed so that the piston chamber reaches a target hydraulic pressure based on the 2nd characteristic by prohibiting the driving of the oil pump along with opening the opening and closing valve.