Torque Converter Centrifugal Clutch Nesting for Compact Lock-Up
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Solution Overview
Problem
The existing torque converters with lock-up devices incorporating centrifugal clutches face challenges in achieving compactness due to the spatial requirements of the centrifugal clutch, which hinders size reduction.
Innovation Solution
The torque converter design positions the centrifugal clutch between the impeller core and the turbine core, utilizing a magnetically actuated centrifugal element that is radially movable and non-rotatable, allowing direct power transmission when the turbine reaches a certain speed, and includes a holding member to maintain the clutch-off state, thereby simplifying the structure and enhancing compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a centrifugal clutch is provided on an outer peripheral part of the clutch plate between the front cover and turbine, then the lock-up function is achieved, but the device size increases due to space requirements in both axial and radial directions
Solution Approach 1:
The centrifugal clutch is relocated from the conventional outer peripheral position to the dead space within the torus structure, utilizing the radial dimension more efficiently. This dimensional repositioning allows the clutch components to occupy space that would otherwise be unused, achieving compactness without compromising the lock-up function.
Solution Approach 2:
The centrifugal clutch components (clutch shoe, clutch plate, spring) are nested within the torus structure of the torque converter. The clutch plate is positioned within the torus, and the clutch shoe engages with the inner surface of the torus, effectively nesting the clutch mechanism within the existing structural framework to minimize overall device volume.
2Volume of moving object
If the centrifugal clutch is disposed in the dead space inside the torus, then compactness is achieved, but the clutch capacity may be reduced due to limited space
Solution Approach 1:
The clutch capacity is enhanced by optimizing the spring constant of the return spring and adjusting the mass distribution of the centrifugal clutch components. By carefully selecting these parameters, sufficient clutch capacity is achieved within the constrained space of the torus dead space.
Solution Approach 2:
The clutch shoe is designed with a composite structure including a friction material layer on the contact surface. This composite construction increases the friction coefficient and clutch capacity without significantly increasing the volume occupied by the clutch components.
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 compact torque converter with improved power transmission efficiency and reduced complexity by using magnetic forces to actuate the clutch, allowing for direct power transfer without the need for additional hydraulic components, thus achieving a more compact and efficient device.
Implementation Method 1
The centrifugal element is pressed onto the friction surface by a centrifugal force acting thereon in rotation of the turbine.
Implementation Method 2
the centrifugal element includes a magnet... the holding member is capable of attracting the magnet of the centrifugal element
Data Source
AI summary
A torque converter includes a front cover to which a power is inputted, an impeller coupled to the front cover, a turbine from which the power is outputted, a stator and a centrifugal clutch. The impeller forms a hydraulic oil chamber together with the front cover. The impeller includes an impeller core. The turbine is opposed to the impeller. The turbine includes a turbine core. The stator is disposed between an inner peripheral part of the impeller and an inner peripheral part of the turbine. The stator is configured to regulate a hydraulic oil flowing from the turbine to the impeller. The centrifugal clutch is disposed in a space between the impeller core and the turbine core. The centrifugal clutch is configured to directly transmit the power from the impeller to the turbine when a rotational speed of the turbine is greater than or equal to a predetermined value.