Cone Clutch Switching Device for Transmission Torque Management
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Solution Overview
Problem
Fully automatic stepped transmissions with multidisk clutches are constructionally complex, heavy, and inefficient due to high drag torques, requiring large installation space and multiple friction points for torque transmission.
Innovation Solution
A compact switching device using a cone clutch with a frictional contact ring, form-fit ring, and actuating body, which reduces the number of friction points and allows for efficient torque transmission by transitioning between frictional and form-fit coupling modes based on torque load, minimizing energy expenditure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multidisk clutches are used for coupling planetary gearset elements, then torque transmission capacity is achieved, but the transmission system becomes constructionally complex, heavy, and requires large installation space
Solution Approach 1:
The clutch mechanism is segmented into distinct functional components: a clutch drum (30) with friction surfaces, clutch shoes (22) with friction cones, and actuating elements (26, 28). This segmentation allows each component to be optimized independently and simplifies the overall construction compared to traditional multidisk clutches
Solution Approach 2:
Hydraulic actuators serve as intermediary elements that convert hydraulic pressure into mechanical motion to actuate the clutch shoes. This intermediary mechanism enables smooth, controlled engagement and disengagement without direct mechanical linkages, reducing constructional complexity
2Strength
If multidisk clutches are used for torque transmission, then sufficient torque capacity is achieved, but the system becomes heavy and requires large installation space
Solution Approach 1:
The clutch shoes feature conical friction surfaces that engage with the clutch drum's friction surfaces. This curved surface geometry allows for compact packaging of the clutch mechanism and reduces the overall volume and weight of the transmission system while maintaining sufficient torque transmission capacity
Solution Approach 2:
The clutch components are arranged in a nested configuration where clutch shoes are positioned radially around the clutch drum, and actuating elements are integrated within the clutch assembly. This nesting minimizes the radial and axial dimensions of the clutch mechanism, reducing installation space and overall weight
3Strength
If multidisk clutches with numerous friction points are used, then maximum torque transmission is achieved, but drag torques increase and transmission efficiency decreases
Solution Approach 1:
The clutch mechanism uses a limited number of friction surfaces (two friction cones engaging with the clutch drum) rather than multiple friction points. This partial action approach is sufficient for the required torque transmission and significantly reduces drag torques and energy losses compared to multidisk clutches with numerous friction surfaces
Solution Approach 2:
The clutch design changes the friction interface parameters by using conical surfaces with optimized cone angles, which improve the mechanical advantage and torque transmission efficiency. This parameter optimization allows for effective torque transmission with fewer friction surfaces, reducing overall energy losses
4Loss of energy
If a compact switching device with fewer friction points is used, then transmission efficiency is improved and drag torques are reduced, but torque transmission capacity may be insufficient for high load cases
Solution Approach 1:
The clutch mechanism dynamically transitions between engaged and disengaged states through hydraulic actuation. The clutch shoes can be rapidly moved into contact with the clutch drum for high-torque situations and separated for normal operation, allowing the system to adapt torque transmission capacity to actual load requirements while maintaining high efficiency during disengagement
Solution Approach 2:
The invention creates a simplified model of the traditional multidisk clutch concept by using a single clutch drum with friction surfaces instead of multiple disks. This copied and simplified approach retains the essential torque transmission function while eliminating the complexity and weight of the original design
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 results in a more compact, energy-efficient transmission system with reduced drag torques and improved efficiency by selectively engaging frictional or form-fit coupling depending on torque requirements, enhancing the overall performance of motor vehicle transmissions.
Implementation Method 1
frictionally coupled in direction of rotation in an axial frictional contact position of the actuating body
Data Source
AI summary
A switching device for a motor vehicle transmission includes a coupling component, several transmission shafts which each are rotatable about a transmission axis, a frictional contact ring including a friction cone and being substantially non-rotatably and axially shiftably connected with a transmission shaft, a form-fit ring including a cone surface and being substantially non-rotatably and axially shiftably connected with the coupling component, as well as an actuating body including a cone surface and being substantially non-rotatably and axially shiftably connected with the coupling component. The friction cone of the frictional contact ring extends between the cone surface of the form-fit ring and the cone surface of the actuating body. The transmission shaft and the coupling component are decoupled in direction of rotation in an axial starting position of the actuating body, frictionally coupled in direction of rotation in an axial frictional contact position of the actuating body and positively coupled in direction of rotation in an axial form-fit position of the actuating body. The form-fit ring in a form-fit position is positively connected with the transmission shaft and in a release position is not positively connected with the transmission shaft. The form-fit ring is axially movable between its form-fit position and its release position and is urged into the release position. In addition, a method for actuating a motor vehicle transmission is provided.