Sheet Metal Multi-Plate Clutch Assembly for Centrifugal Oil Compensation
Solution Overview
Problem
Existing dual-clutch transmissions in hybrid vehicles face issues with centrifugal force affecting clutch actuation, leading to pressure increases and disruptive effects, which hinder efficient shifting in electric mode without traction interruption, and require optimized designs for limited installation space and cost-effective manufacturing.
Innovation Solution
A multi-plate clutch arrangement with radially offset plate packs and pistons made of sheet metal, featuring integrated seals and centrifugal oil compensation chambers, allowing for a compact and cost-optimized design that enables seamless shifting in electric mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple friction clutches are arranged radially offset on plate carriers, then the clutch assembly can achieve compact design for limited installation space, but the axial expansion increases
Solution Approach 1:
The patent applies nesting by placing multiple friction clutches radially offset from each other on common plate carriers, with inner clutches positioned within the radial space of outer clutches. This nested radial arrangement allows three friction clutches to be compactly arranged in a limited installation space without significant axial expansion, as each clutch occupies a different radial zone rather than stacking axially.
2Ease of manufacture
If pistons are made of sheet metal in one piece, then manufacturing costs are reduced and manufacturing precision is improved, but the sealing complexity increases
Solution Approach 1:
The patent merges the sealing function directly into the sheet metal piston by vulcanizing sealing lips onto the piston surface. This integration eliminates the need for separate sealing components and assemblies, reducing overall part count and manufacturing complexity while maintaining effective sealing between pressure chambers and centrifugal oil compensation chambers.
Solution Approach 2:
The patent uses composite construction by combining sheet metal for the piston body with vulcanized rubber or elastomeric material for the sealing lips. This composite approach leverages the strength and rigidity of sheet metal for structural integrity while using the elastic properties of vulcanized material for effective sealing, achieving both cost-effectiveness and functional performance.
3Reliability
If centrifugal oil compensation chambers are provided to counteract centrifugal force effects, then clutch actuation reliability is improved, but the device complexity increases
Solution Approach 1:
The patent makes the piston serve multiple functions: it acts as both the actuating element for the friction clutch and as a boundary element for the centrifugal oil compensation chamber. The single-piece sheet metal piston with integrated sealing lips simultaneously performs clutch actuation, sealing of pressure chambers, and definition of centrifugal compensation chambers, eliminating the need for separate compensation mechanisms and reducing overall device complexity.
Solution Approach 2:
The centrifugal oil compensation chambers are designed to automatically generate counter-pressure through centrifugal force during rotation, without requiring external control systems or additional actuating mechanisms. The oil naturally migrates to create balancing pressure that counteracts centrifugal effects on the piston, providing self-regulating reliable clutch actuation.
4Reliability
If seals are vulcanized to the sheet metal pistons, then sealing effectiveness is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the material state and bonding parameters by using vulcanization to chemically bond the sealing lips to the sheet metal piston surface. This thermal-chemical bonding process creates a strong, permanent attachment that maintains sealing effectiveness under high-pressure and high-temperature clutch operating conditions, while the integrated one-piece construction minimizes the number of precision-critical interfaces.
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 provides a compact, cost-effective triple-plate clutch design that minimizes axial expansion, reduces manufacturing costs, and enables traction-free shifting in hybrid vehicles, enhancing efficiency and reducing emissions.
Implementation Method 1
the aim is to counteract the sometimes disruptive effects of centrifugal force on rotating actuating pistons—namely, pressure increases caused by the cooling oil, intended for clutch actuation, being flung outwards by centrifugal force during rotation—by providing corresponding compensation chambers in which a corresponding counter-pressure is generated
Implementation Method 2
the pistons have seals that are vulcanized to the sheets of the pistons and seal at least the respective pressure chamber against other components of the multi-plate clutch
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Disclosed is a multi-disc clutch arrangement having at least two friction clutches which comprise disc stacks that are radially offset to each other and disposed on disc carriers (9), and having pistons (13, 14) which serve to actuate the friction clutches, wherein the pistons (13, 14) delimit pressure chambers (40, 41) in relation to centrifugal-oil compensating chambers (21, 22), at least one of said pistons (13, 14, 15) being made of sheet metal and in the form of a single piece. The clutch preferably comprises a ring gear (30), which is mounted on a ring gear supporting plate (20) on a main hub and has an installation space (30C) serving as pressure chamber. The radial part and an axial part of the piston (13) of the clutch, which is a disconnect clutch between an internal combustion engine and a transmission, are positioned in the installation space (30C).