Rotation Transmission Clutch Switching to Block Reverse Back-EMF
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Solution Overview
Problem
The drive unit for electric automobiles, as described in JP H09-226394 (A), faces issues when the electric motor is stopped, causing excessive reverse electromotive voltage and complicating the structure and control of clutch connection and disconnection, leading to an unpleasant driving experience due to potential shocks during clutch engagement.
Innovation Solution
A rotation transmission state switching device is introduced, comprising a clutch device and a restriction device, which includes a braking mechanism or an electric motor to control torque transmission between the electric motor and drive wheels, allowing for simplified configuration and reduced complexity in switching between connected and disconnected states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a clutch is provided between the electric motor and drive wheels to separate them when the motor is stopped, then excessive reverse electromotive voltage is prevented, but the structure and control become complicated and shocks occur during engagement
Solution Approach 1:
A one-way clutch mechanism is introduced as an intermediary device between the electric motor and drive wheels. This clutch automatically engages or disengages based on the direction of torque transmission, eliminating the need for complex active control systems while preventing reverse torque from generating excessive electromotive voltage in the motor.
2Object-affected harmful factors
If a clutch is provided between the electric motor and drive wheels to separate them when the motor is stopped, then torque transmission is controlled, but shocks occur during clutch engagement giving unpleasant sensation
Solution Approach 1:
The one-way clutch mechanism operates automatically based on the direction of torque flow without requiring active control. When reverse torque is applied to the motor, the clutch automatically disengages, preventing shock transmission to the driver while maintaining simple and reliable operation.
3Power
If the electric motor functions as an electric generator during engine-only travel, then torque is transmitted to drive wheels, but excessive reverse electromotive voltage is generated
Solution Approach 1:
The one-way clutch acts as a mechanical intermediary that blocks reverse torque transmission from the drive wheels to the electric motor. This prevents the motor from generating excessive reverse electromotive voltage while allowing the vehicle to travel using engine power alone.
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 provides a more simplified structure for the drive unit, reducing manufacturing costs and eliminating the unpleasant sensations caused by clutch engagement shocks, while effectively managing torque transmission and preventing excessive reverse electromotive voltage.
Implementation Method 1
a restriction device configured so as to be able to switch between a state where rotation of the first rotating member is allowed and a state where rotation of the first rotating member is restricted
Implementation Method 2
an engaging element having an engaging-element-side first engaging portion that engages with the first-rotating-member-side engaging portion, an engaging-element-side second engaging portion that engages with the second-rotating-member-side engaging portion, and an engaging-element-side third engaging portion that engages with the third-rotating-member-side engaging portion
Data Source
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AI summary
To provide a rotation transmission state switching device having a more simplified configuration. The rotation transmission state switching device comprises a clutch device comprising a first rotating member having a first-rotating-member-side engaging portion, a second rotating member having a second-rotating-member-side engaging portion, a third rotating member having a third-rotating-member-side engaging portion; and an engaging element having an engaging-element-side first engaging portion that engages with the first-rotating-member-side engaging portion, an engaging-element-side second engaging portion that engages with the second-rotating-member-side engaging portion, and an engaging-element-side third engaging portion that engages with the third-rotating-member-side engaging portion; and a restriction device configured so as to be able to switch between a state where rotation of the first rotating member is allowed and a state where rotation of the first rotating member is restricted; torque transmission between the second rotating member and the third rotating member being allowed when rotation of the first rotating member is allowed by the restriction device, whereas torque transmission between the second rotating member and the third rotating member is not possible when rotation of the first rotating member is prevented by the restriction device.