Flow Regulating Valve for Limited-Slip Driveline Clutch Actuation
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Solution Overview
Problem
Limited-slip driveline clutches in differentials face challenges in controlling rotational slip without requiring expensive electronic control systems, as existing hydraulic actuation methods rely on precise pressure control which can be costly and inefficient.
Innovation Solution
A pressure-compensated flow control valve is used to regulate hydraulic fluid flow rate, preventing it from exceeding a set maximum, allowing for actuation control based solely on flow rate, independent of hydraulic pressure, and incorporating a hydraulic pump and piston to actuate the clutch in a differential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a non-compensated orifice is used to regulate hydraulic fluid flow, then the device complexity is reduced and cost is decreased, but the actuation pressure becomes highly sensitive to pump flow rate variations leading to poor control precision
Solution Approach 1:
A flow regulating valve is introduced as an intermediary component between the hydraulic pump and the clutch actuation system. This valve mediates the relationship between pump flow rate and clutch actuation pressure, ensuring that the clutch receives consistent actuation pressure regardless of pump flow variations. The flow regulating valve translates variable pump output into stable clutch actuation, resolving the contradiction between simple device design and precise pressure control.
2Ease of manufacture
If a simple orifice is used for flow regulation, then manufacturing cost is reduced, but the actuation pressure varies significantly with pump flow rate causing unreliable clutch engagement
Solution Approach 1:
The flow regulating valve is designed to automatically adjust and maintain proper flow rates without external control systems. The valve self-regulates the hydraulic fluid flow to the clutch based on system conditions, ensuring reliable clutch engagement across varying operating conditions. This self-service capability eliminates the need for expensive electronic controllers while maintaining reliable actuation.
3Force
If hydraulic pressure control is used to actuate the clutch, then the clutch engagement force can be precisely controlled, but the system requires expensive electronic control hardware and software
Solution Approach 1:
The patent replaces electronic pressure control systems with a mechanically-based flow regulation system. Instead of using electronic controllers and solenoid valves to manage clutch actuation pressure, the invention uses a flow regulating valve that mechanically controls hydraulic fluid flow rates. This mechanical substitution eliminates expensive electronic hardware while maintaining precise control over clutch engagement force through flow rate management.
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 solution enables effective control of relative rotational speed between driveline components without the need for expensive electronic controls, ensuring efficient operation and traction management in differential applications.
Implementation Method 1
A hydraulic pump is provided in the actuation arrangement for pumping hydraulic fluid through the hydraulic circuit when relative rotation exists between the first and second driveline components. Hydraulic pressure generated by the hydraulic pump within the hydraulic circuit is used to actuate the clutch.
Implementation Method 2
A flow regulating valve is provided for regulating a hydraulic fluid flow rate through the hydraulic circuit. The flow regulating valve is configured to prevent the hydraulic fluid flow rate from exceeding a set maximum flow rate regardless of a magnitude of the hydraulic pressure in the hydraulic circuit.
Data Source
AI summary
A limited-slip driveline apparatus including a first driveline component that is rotatable relative to a second driveline component. The driveline apparatus also includes a clutch. The driveline apparatus further includes an actuation arrangement for actuating the clutch. The actuation arrangement includes a hydraulic pump that pumps hydraulic fluid through a hydraulic circuit when relative rotation exists between the first and second driveline components. The hydraulic pressure generated by the hydraulic pump within the hydraulic circuit is used to actuate the clutch. The actuation arrangement also includes a flow regulating valve for regulating a hydraulic fluid flow rate through the hydraulic circuit. The flow regulating valve is configured to prevent the hydraulic fluid flow rate from exceeding a set maximum flow rate regardless of a magnitude of the hydraulic pressure in the hydraulic circuit.