Engageable Coupling Assembly Pumping Fluid to Reduce Overrun Torque Loss
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Solution Overview
Problem
Existing one-way clutches in automotive transmissions experience significant torque loss during overrun conditions, which is a concern for transmission efficiency.
Innovation Solution
An engageable coupling assembly utilizing pressurized fluid with annular faces, fluid grooves, and pumping grooves is designed to reduce spin losses by efficiently conveying fluid out of the assembly during overrun conditions, thereby minimizing torque requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional one-way clutches are used in automotive transmissions, then the clutch can provide one-way torque transfer functionality, but significant torque loss occurs during overrun conditions
Solution Approach 1:
The patent extracts the fluid management function from the conventional clutch design by adding separate fluid grooves and pumping grooves that actively remove pressurized fluid from the annular space during overrun conditions, thereby reducing torque loss without affecting the one-way torque transfer functionality
Solution Approach 2:
The patent applies hydraulic principles by utilizing pressurized fluid dynamics to create pumping grooves that actively pump fluid out of the annular space during overrun, converting the harmful fluid pressure into a beneficial pumping action that reduces spin losses and improves transmission efficiency
2Reliability
If fluid is retained in the annular space during overrun, then lubrication is maintained, but spin losses increase due to fluid drag
Solution Approach 1:
The patent implements dynamic fluid management where the fluid grooves and pumping grooves are designed to adaptively respond to rotation direction and speed, automatically retaining fluid during normal operation for lubrication while actively pumping fluid out during overrun conditions to reduce spin losses
Solution Approach 2:
The pumping grooves create periodic fluid evacuation action during overrun conditions, where the rotating assembly periodically draws fluid into and expels fluid from the annular space through the pumping grooves, maintaining lubrication while reducing continuous fluid drag
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 effectively reduces spin losses by pumping pressurized fluid out of the assembly during overrun, enhancing transmission efficiency by minimizing the torque needed to spin the clutch.
Implementation Method 1
A rotating one of the coupling members has the exterior surface. The exterior surface defines a plurality of pumping grooves in fluid communication with the set of fluid passages. The pumping grooves are configured to pump the pressurized fluid from the annular space, through the fluid passages and over the retaining member during an overrun condition
Implementation Method 2
The fluid grooves are configured to conduct the pressurized fluid from the annular space and out of the assembly in an axial direction during an overrun condition of the assembly, thereby reducing spin losses when the assembly is disengaged
Data Source
AI summary
An engageable coupling assembly having reduced spin losses and method of assembling such assembly within an automotive transmission to reduce such losses are provided. The assembly is adapted for use with pressurized fluid. The assembly includes first and second coupling members that are supported with respect to each other for relative rotation about a common rotational axis. The coupling members have a first pair of annular faces that oppose each other and define an annular space therebetween. A first face of the first pair has a set of pockets spaced about the rotational axis. A second face of the first pair has a set of locking formations. The coupling members have a second pair of annular faces that oppose each other. A first face of the second pair defines a first set of fluid grooves fluidly communicating the annular space with an exterior surface of the assembly. The fluid grooves are configured to conduct the pressurized fluid from the annular space and out of the assembly in an axial direction during an overrun condition of the assembly, thereby reducing spin losses when the assembly is disengaged.