Hybrid Vehicle Disconnect Clutch Shell Design
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Solution Overview
Problem
There is a need for a modular powertrain module for hybrid electric vehicles that can be installed between various engines and transmissions, incorporating a hydraulically actuated disconnect clutch, an electric machine, and suitable power paths, while maintaining low manufacturing and assembly costs and ensuring reliable performance without requiring vehicle body modifications.
Innovation Solution
The module includes a shell fixed against axial displacement, a clutch with plates secured by a spline, a retainer for limiting axial movement, and a piston to force the plates toward the retainer, securing the wet disconnect clutch pack to the electric machine rotor with a single snap ring, allowing uniform clutch plates and efficient heat transfer for cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a reaction block were used to support the clutch plates, then the clutch structure would be more robust, but the manufacturing cost and assembly complexity would increase
Solution Approach 1:
The shell is designed to perform multiple functions simultaneously: it serves as the clutch plate support structure, the heat dissipation component, and the mounting interface for the snap ring. By merging these functions into a single integrated component rather than using separate reaction blocks and supports, the patent reduces part count and assembly complexity while maintaining structural robustness
Solution Approach 2:
The shell is designed as a multi-functional component that provides structural support for the clutch plates, acts as a heat sink for thermal management, and serves as the mounting interface for the snap ring retention system. This universal design eliminates the need for separate dedicated components for each function, reducing overall system complexity
2Reliability
If multiple retention components were used to secure the clutch pack, then the connection would be more secure, but the assembly complexity and manufacturing cost would increase
Solution Approach 1:
Multiple retention functions are consolidated into a single snap ring component. The snap ring simultaneously provides axial retention, radial positioning, and torque transmission support for the clutch pack, eliminating the need for multiple separate retention components while maintaining connection security
Solution Approach 2:
The snap ring is designed to automatically engage and lock into the shell's retention groove, providing self-retaining functionality without requiring additional fasteners, clips, or adjustment mechanisms. The elastic nature of the snap ring allows it to self-adjust and maintain constant retention pressure
3Ease of manufacture
If thinner clutch plates were used to reduce material cost, then manufacturing cost would decrease, but heat dissipation capability would be reduced
Solution Approach 1:
The shell acts as an intermediary thermal management component between the clutch plates and the surrounding environment. It provides a dedicated heat dissipation pathway by conducting thermal energy from the clutch plates through its mass and surface area to the ambient cooling airflow, allowing thinner clutch plates to maintain adequate thermal management
Solution Approach 2:
The design utilizes airflow (pneumatic cooling) to enhance heat dissipation from the shell. The shell's positioning and geometry facilitate cooling airflow passage, creating a convective cooling system that compensates for the reduced thermal mass of thinner clutch plates
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 enables a cost-effective, reliable powertrain module that can be used across different vehicles, providing efficient torque transmission and cooling while maintaining low manufacturing and assembly costs, and ensuring reliable performance without vehicle body modifications.
Implementation Method 1
Because the shell is in contact with clutch plates, heat is readily transferred from the clutch plates to the shell, thereby providing a heat flow path for cooling the clutch plates
Data Source
AI summary
An assembly includes a shell fixed against axial displacement, a clutch including first plates secured to the shell by a spline, a member fixed against axial displacement, supporting the shell and secured to the shell by the spline, a retainer for limiting axial movement of the first plates and member along the spline, and a piston for forcing the plates along the spline toward the retainer.