Torque Converter Centrifugal Clutch Nesting for Compact Packaging
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Solution Overview
Problem
The existing torque converters with lock-up devices incorporating centrifugal clutches face challenges in compactness due to the axial and radial space requirements, hindering their 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 is held by a magnetic force when not in use, thus occupying dead space and simplifying the structure.
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 device can be implemented, but the torque converter size increases due to axial and radial space occupation
Solution Approach 1:
The centrifugal clutch is relocated from the conventional outer peripheral position to the dead space between the impeller core and turbine core. This spatial repositioning utilizes the available radial space more efficiently, placing the clutch mechanism in a previously underutilized dimension of the torque converter structure, thereby reducing overall size while maintaining functionality
Solution Approach 2:
The centrifugal clutch components (centrifugal elements, clutch plates) are nested within the existing structural framework of the torque converter, specifically within the space between the impeller core and turbine core. This nesting approach allows the clutch mechanism to be accommodated within the existing boundaries without requiring additional external space
2Reliability
If a centrifugal clutch is provided on an outer peripheral part of the clutch plate, then the lock-up device can be implemented, but the device complexity increases due to additional hydraulic components
Solution Approach 1:
The patent replaces the conventional hydraulic actuation system with a centrifugal actuation mechanism. The centrifugal elements utilize centrifugal force generated during rotation to automatically engage and disengage the clutch plates, eliminating the need for hydraulic pistons, seals, and fluid pressure control systems, thereby simplifying the overall device structure
Solution Approach 2:
The centrifugal clutch operates autonomously based on the rotational speed of the torque converter. As the rotational speed increases, centrifugal force automatically pushes the centrifugal elements outward to engage the clutch plates, and as speed decreases, spring force automatically returns the elements to disengage position, eliminating the need for external hydraulic control systems
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 enables a compact torque converter size while maintaining efficient power transmission and increasing clutch capacity, eliminating the need for additional hydraulic components and simplifying the structure by using magnetic forces for actuation.
Implementation Method 1
The centrifugal element includes a magnet. When the impeller core is made of, for instance, ferromagnetic material such as iron, the centrifugal element is pressed onto the friction surface not only by the centrifugal force but also by a magnetic force.
Implementation Method 2
The centrifugal element is pressed onto the friction surface by a centrifugal force acting thereon in rotation of the turbine.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
It is intended to realize compactness in device size for a torque converter including a lock-up device using a centrifugal clutch. The present torque converter (1) includes a front cover (2), an impeller (10), a turbine (11), a stator (12) and a centrifugal clutch (4). The impeller (10) is coupled to the front cover (2), forms a hydraulic oil chamber together with the front cover (2), and includes an impeller core (17). The turbine (11), from which power is outputted, is provided in opposition to the impeller (10) and includes the turbine core (22). The stator (12) is disposed between an inner peripheral part of the impeller (10) and that of the turbine (11), and regulates the flow of hydraulic oil flowing from the turbine (11) to the impeller (10). The centrifugal clutch (4) is disposed in a space between the impeller core (17) and the turbine core (22), and directly transmits the power from the impeller (10) to the turbine (11) when a rotational speed of the turbine (11) is greater than or equal to a predetermined value.