Double Clutch Unit Bearing Layout for Axial Wear Control
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Solution Overview
Problem
Double clutch units in DCTs face wear issues due to axial and radial movements of shafts, which are exacerbated by limited axial packaging space in sports car transaxles, leading to increased wear mechanisms and complexity in assembly and disassembly.
Innovation Solution
A double clutch unit configuration featuring an outer and inner clutch pack with a spring-loaded bolt that maintains axial alignment, supported by a stator and oil distributor-stator bearing assembly, which limits axial movement and simplifies assembly and disassembly by transmitting axial forces through thrust and angular contact bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If axial forces are taken up by bearings in the gearbox to maintain axial position of shafts, then axial alignment is maintained, but axial play in bearings causes small axial movements that transmit wear mechanisms through clutch parts
Solution Approach 1:
A thrust bearing is introduced as an intermediary element between the clutch packs and the gearbox bearings. This thrust bearing absorbs axial movements and forces, preventing them from being transmitted through the clutch packs. The thrust bearing acts as a mediator that protects the clutch friction plates from wear caused by axial play in the gearbox bearings.
2Volume of moving object
If limited axial packaging space is used in sports car transaxle, then compact design is achieved, but axial space constraints force usage of concentric clutches increasing complexity
Solution Approach 1:
The patent employs a nested concentric clutch configuration where an inner clutch pack and an outer clutch pack are arranged one inside the other along the same axial space. This nesting approach allows two clutches to function within the limited axial packaging space of sports car transaxles, achieving compact design while maintaining the necessary clutch functionality through careful spatial arrangement.
3Stability of the object's composition
If radial bearings support clutch packs radially, then radial stability is maintained, but small radial movements transmit wear mechanisms through oil distributor and carrier plates
Solution Approach 1:
Radial bearings are introduced as intermediary elements between the clutch packs and the oil distributor/carrier plates. These radial bearings absorb and isolate small radial movements, preventing them from being transmitted through the oil distributor and carrier plates to the clutch friction plates, thereby protecting against wear mechanisms while maintaining radial stability.
4Force
If clutch packs are allowed to move axially during breaking and acceleration due to inertia, then inertia forces are absorbed, but movement sets up wear mechanisms that cannot be limited by spring bolt
Solution Approach 1:
The thrust bearing serves as a mediator that allows clutch packs to absorb inertia forces during breaking and acceleration while preventing actual movement that would cause wear. The thrust bearing accommodates axial loads and inertial forces without permitting the relative movement between clutch components that would generate wear mechanisms.
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 configuration reduces wear mechanisms by constraining axial movements, enhances assembly and disassembly ease, and optimizes packaging space, resulting in a more reliable and compact double clutch unit.
Implementation Method 1
a spring-loaded bolt (62) which applies an axial force in the gearbox direction to the inner output hub (8), that is transmitted in order to the outer output hub (17), oil distributor (9) and ultimately to the stator (60)
Implementation Method 2
an oil distributor-stator bearing assembly (86, 88; 54, 86, 88; 19, 54, 86, 88) which supports axial rotation of the oil distributor (9) on the stator (60) and limits axial movement of the oil distributor (9) relative to the stator (60)
Implementation Method 3
one or more angular contact bearings (19) which limit axial movement of the oil distributor (9) relative to the stator (60)
Implementation Method 4
an outer clutch pack (40) and an inner clutch pack (30), each having a clutch pack input (42, 32) and a clutch pack output (44, 34)
Data Source
AI summary
A double clutch unit for a transmission, having an outer clutch pack and an inner clutch pack each having a clutch pack input and a clutch pack output, wherein a clutch unit input hub rotationally fixed to the outer clutch pack input side and the inner clutch pack input side, a clutch unit inner output hub attached in fixed rotational relation to the outer clutch pack output side, a clutch unit outer output hub attached in fixed rotational relation to an inner clutch pack output side, and an oil distributor rotationally fixed to the inner clutch pack input side, are axially slidable relative to a stator, and a spring-loaded bolt is attached to the engine side of a clutch unit inner power output shaft maintaining the inner output hub, clutch unit outer output hub and oil distributor in axial alignment with respect to the stator.