Torque Converter Lock-up Device Segmented Hydraulic Control
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Solution Overview
Problem
Existing lock-up devices for torque converters face a trade-off between achieving better slip control performance and maintaining a desired lock-up torque capacity, as reducing the gradient of torque with respect to hydraulic pressure to enhance slip control also reduces the lock-up torque capacity, making it difficult to achieve both simultaneously.
Innovation Solution
The design incorporates a lock-up device with a piston, clutch part, and hydraulic chambers, where the piston is axially slidable and the hydraulic chambers are sealed except for communication with hydraulic ports, allowing for equal pressure receiving areas and independent operation of the first and second hydraulic chambers to manage hydraulic pressure effectively, thereby reducing the load on the hydraulic pump without increasing the torque/hydraulic-pressure variation gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the gradient of torque with respect to hydraulic pressure is reduced to improve slip control performance, then slip control performance is improved, but lock-up torque capacity is reduced
Solution Approach 1:
The hydraulic chamber is divided into a first hydraulic chamber and a second hydraulic chamber that are sealed independently from each other. The first hydraulic chamber communicates with a first hydraulic port, while the second hydraulic chamber communicates with a second hydraulic port. This segmentation allows independent pressure control in each chamber, enabling the system to achieve both low torque/hydraulic-pressure variation gradient (for good slip control) and sufficient lock-up torque capacity by coordinating pressure in both chambers.
2Use of energy by moving object
If the gradient of torque with respect to hydraulic pressure is reduced to reduce fuel consumption, then fuel consumption is reduced, but lock-up torque capacity is reduced
Solution Approach 1:
The hydraulic chamber is divided into a first hydraulic chamber and a second hydraulic chamber that are sealed independently from each other. The first hydraulic chamber communicates with a first hydraulic port, while the second hydraulic chamber communicates with a second hydraulic port. This segmentation allows independent pressure control in each chamber, enabling the system to achieve both low torque/hydraulic-pressure variation gradient (for good slip control and reduced fuel consumption) and sufficient lock-up torque capacity by coordinating pressure in both chambers.
3Ease of operation
If the gradient of torque with respect to hydraulic pressure is reduced to improve slip control, then slip control is improved, but hydraulic pump load is increased
Solution Approach 1:
The hydraulic chamber is divided into a first hydraulic chamber and a second hydraulic chamber that are sealed independently from each other. The first hydraulic chamber communicates with a first hydraulic port, while the second hydraulic chamber communicates with a second hydraulic port. This segmentation allows independent pressure control in each chamber, enabling the system to achieve both low torque/hydraulic-pressure variation gradient (for good slip control) and sufficient lock-up torque capacity by coordinating pressure in both chambers, while managing hydraulic pump load through efficient pressure distribution.
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 allows for improved slip control performance while maintaining a desired lock-up torque capacity, reducing fuel consumption and hydraulic pump load without deteriorating slip control, and ensures reliable actuation of the piston.
Implementation Method 1
the piston divides the space produced between the front cover and the turbine into a first hydraulic chamber on the front cover side and a second hydraulic chamber on the turbine side, and is axially movable by differential pressure between the first hydraulic chamber and the second hydraulic chamber
Implementation Method 2
the piston has a friction member, which can be frictionally coupled to the front cover, on the outer peripheral part thereof
Implementation Method 3
when the operating oil is drained from the first hydraulic chamber, the hydraulic pressure in the second hydraulic chamber becomes higher than that in the first hydraulic chamber, and the piston is moved towards the front cover. The friction member mounted to the piston is then pressed onto the front cover
Data Source
AI summary
A lock-up device for a torque converter includes a piston, a clutch part, a first hydraulic chamber, a second hydraulic chamber, a first hydraulic port and a second hydraulic port. The first hydraulic chamber is formed on a piston side of the front cover. The second hydraulic chamber is formed independently from the first hydraulic chamber. The first hydraulic port is in communication with the first hydraulic chamber. The second hydraulic port is formed independently from the first hydraulic port, and a portion of the second hydraulic chamber is in communication with the second hydraulic port. The first hydraulic chamber is sealed with the exception of a portion of the first hydraulic chamber that is in communication with the first hydraulic port. The second hydraulic chamber is sealed with the exception of the portion of the second hydraulic chamber that is in communication with the second hydraulic port.