Friction Plate Sectorial Oil Grooves Drag Torque Reduction
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Solution Overview
Problem
Conventional wet type clutches experience significant power loss due to drag torque, which is not adequately reduced by existing friction plates, especially with the miniaturization trend leading to closer distances between friction and mating plates.
Innovation Solution
The friction plate design features radially extending oil grooves with sectorial shapes, alternating perimeter and inner circumference side vertices, optimized to enhance lubricant discharge and retention, reducing drag torque through centrifugal force manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional oil groove designs are used, then manufacturing is simple, but drag torque is not sufficiently reduced
Solution Approach 1:
The oil groove is divided into multiple radial grooves that extend from the inner circumference toward the outer circumference. Each groove acts as an independent channel for lubricant discharge, enhancing the overall effectiveness of drag torque reduction while maintaining a relatively simple manufacturing process.
Solution Approach 2:
The friction plate incorporates friction material segments with varying properties in different regions. The friction material has higher friction coefficients near the inner circumference and lower friction coefficients near the outer circumference, optimizing torque transmission and drag torque reduction in different zones of the clutch assembly.
2Power
If friction material is uniformly distributed, then manufacturing is easy, but torque transmission efficiency is insufficient
Solution Approach 1:
The friction material is distributed non-uniformly across the friction plate, with higher concentrations near the inner circumference and lower concentrations near the outer circumference. This gradient distribution optimizes torque transmission by providing higher friction where needed while reducing drag torque in outer regions.
Solution Approach 2:
The friction material is divided into discrete segments separated by radial grooves. This segmentation allows for optimized friction characteristics in different zones while maintaining ease of manufacturing through modular construction.
3Volume of moving object
If clutch plates are positioned closer together, then miniaturization is achieved, but drag torque increases
Solution Approach 1:
Multiple radial grooves divide the lubricant discharge function into several channels, improving the efficiency of lubricant removal from the engagement interface. This enhanced discharge capability reduces drag torque even when the clutch plates are positioned closer together for miniaturization.
Solution Approach 2:
The friction material distribution and groove positioning are optimized to create regions of high and low friction coefficients. This local optimization allows the clutch to maintain compact dimensions while minimizing drag torque through strategic placement of friction and lubrication zones.
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 design significantly reduces drag torque by efficiently discharging lubricant and increasing air content, addressing the limitations of conventional technologies and meeting the demand for miniaturized clutch systems.
Implementation Method 1
Oil grooves are usually provided between the adjacent friction material segments, or in the friction materials in the radial direction so that lubricating oil may be discharged by a centrifugal force to the perimeter sides of the friction plates
Implementation Method 2
It is known that the drag torque may be reduced by increasing the content of air in the lubricating oil
Data Source
AI summary
Problem—To provide a friction plate with reduced drag torque.Solution—The friction plate is formed with oil grooves having the sectorial shapes spreading toward the inner circumference and the perimeter. The adjacent edges of the friction material segments are provided with the perimeter side vertex and the inner circumference side vertex respectively. The sectorial oil groove opening toward the perimeter side from the inner circumferential side vertexes can discharge a lube oil to the perimeter side efficiently by a centrifugal force. Also, owing to the sectorial oil groove opening toward the inner circumference side from the perimeter side vertexes, a lube oil can be made to run aground onto the friction material segments due to a centrifugal force, thus, reducing the drag torque markedly compared with the conventional plates.