Clutch Apparatus Control for Responsiveness and Overshoot
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Solution Overview
Problem
Existing clutch apparatuses face challenges in improving responsiveness while suppressing drag torque and rotational force overshoot, especially when operated by an electric motor in four-wheel drive vehicles, leading to adverse vehicle behavior and reduced durability of downstream components.
Innovation Solution
A clutch apparatus with a multi-plate clutch system, an electric motor, and a control unit that adjusts rotational force by moving a pressing member axially in response to varying electric current, allowing for precise control of the rotational force transmitted between rotating members, thereby enhancing responsiveness and reducing drag torque and overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric motor is rotated at higher angular accelerations and higher speeds to quickly press the multi-plate clutch, then the responsiveness is improved, but the rotational force transmitted through the multi-plate clutch temporarily exceeds the target rotational force causing overshoot
Solution Approach 1:
The control unit supplies electric current having a first current value that is greater than a second current value corresponding to a target rotational force, thereby moving the pressing member in the axial direction before the target rotational force is reached. This preliminary action eliminates clearances and prepares the multi-plate clutch for efficient torque transmission, improving responsiveness while preventing overshoot through controlled current reduction afterward.
2Speed
If a biasing member is used to eliminate clearances in the multi-plate clutch, then the responsiveness is improved, but the rotational force is transmitted to the downstream side due to drag torque when the electric motor generates no torque
Solution Approach 1:
The invention removes the biasing member from the clutch apparatus structure. Instead of using a mechanical biasing member to eliminate clearances, the control unit uses controlled electric current supply to the motor, which moves the pressing member axially to eliminate clearances only when needed. This extraction of the biasing member eliminates the source of continuous drag torque while maintaining responsiveness through active control.
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 effectively improves the responsiveness of the clutch apparatus, reduces drag torque, and suppresses rotational force overshoot, ensuring better vehicle performance and extended durability of components in the drive force transmission path.
Implementation Method 1
an electric motor that is supplied with electric current and that generates torque in accordance with the electric current
Implementation Method 2
a multi-plate clutch having a first clutch plate that rotates together with the first rotating member, and a second clutch plate that is aligned with the first clutch plate in an axial direction and that rotates together with the second rotating member
Data Source
AI summary
A clutch apparatus includes a clutch hub, a clutch drum, a multi-plate clutch having inner clutch plates and outer clutch plates, a piston for pressing the multi-plate clutch, an electric motor, a moving mechanism for moving the piston in an axial direction in accordance with the amount of rotation of the electric motor, and a control unit for controlling the electric motor. When increasing a rotational force that is transmitted between the clutch hub and the clutch drum by increasing electric current that is supplied to the electric motor, the control unit moves the piston in the axial direction by temporarily supplying the electric motor with the electric current having a first current value that is greater than a second current value corresponding to a target rotational force that needs to be transmitted between the clutch hub and the clutch drum.