Auxiliary Drive Device with Meshing Clutch and Synchronized Engagement
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Solution Overview
Problem
In four-wheel-drive vehicles, existing auxiliary drive devices with electromagnetic clutches experience delays and generate vibration/noise when switching to four-wheel-drive mode, due to the time required for clutch engagement and friction between clutch plates.
Innovation Solution
A meshing clutch system with first and second meshing members and an actuator that controls the meshing process, allowing for synchronized rotation and reduced current supply to minimize vibration and noise during engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a meshing clutch is used to transfer drive force through meshing teeth, then the auxiliary drive wheels can be engaged quickly, but significant vibration or noise is generated during meshing
Solution Approach 1:
The control unit supplies current to the electric motor before the meshing clutch is fully engaged (when the second meshing member is between the abutment position and meshing position), causing the first and second meshing members to rotate in synchronization prior to meshing. This preliminary synchronized rotation eliminates the impact and noise that would occur when rotating parts suddenly engage, while still achieving quick engagement response.
2Power
If a multi-plate clutch with cam thrust force is used, then the clutch can transfer torque, but it takes time for the electromagnetic clutch to engage and friction force to develop
Solution Approach 1:
The patent replaces the traditional multi-plate clutch with cam thrust mechanism with a meshing clutch system that uses direct tooth-to-tooth meshing for torque transfer. This mechanical substitution eliminates the need for friction-based engagement and cam mechanism actuation, enabling instantaneous torque transfer capability while reducing engagement time through direct positive engagement of meshing teeth.
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 meshing clutch system reduces vibration and noise while quickly engaging the auxiliary drive wheels, enhancing the responsiveness and comfort of four-wheel-drive transitions.
Implementation Method 1
a drive unit that has an electric motor that generates a drive force that matches a supplied current
Implementation Method 2
a meshing clutch that has a first meshing member including first meshing teeth and a second meshing member including second meshing teeth, and that allows and blocks torque transfer between the electric motor and the auxiliary drive wheels
Implementation Method 3
an actuator that causes the first meshing teeth and the second meshing teeth to be meshed with each other by moving the second meshing member in an axial direction with respect to the first meshing member
Data Source
AI summary
An auxiliary drive device includes: a drive unit that has an electric motor; a meshing clutch that has a first meshing member and a second meshing member; an actuator that moves the second meshing member; and a control unit that controls the electric motor and the actuator. The actuator moves the second meshing member among a separation position, at which the second meshing member is not meshed with the first meshing member, an abutment position, at which first meshing teeth and second meshing teeth possibly abut against each other, and a meshing position, at which the first meshing teeth and the second meshing teeth are meshed with each other. The control unit makes a current supplied to the electric motor when the second meshing member is located between the abutment position and the meshing position smaller than a current required to maintain the rotational speed of the electric motor.