Planetary AWD Torque Control to Prevent Opposite Output Torques
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Solution Overview
Problem
In motive power transmission devices equipped with differential devices, the directions of torques from respective output shafts often become opposite to each other, leading to inefficiencies and potential damage.
Innovation Solution
A control apparatus that restricts the differential effect of the differential device more when the torque of the first output shaft is equal to or smaller than a threshold, using an engagement device to selectively couple rotating elements and control the torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the differential device acts in a differential manner to transmit motive power from the second motive power source, then the motive power can be distributed to both front and rear wheels, but the directions of torques of the respective output shafts may become opposite to each other
Solution Approach 1:
The patent applies dynamics by making the differential device's operation variable based on operating conditions. The control device dynamically adjusts whether the differential device operates in differential mode or locked mode depending on the torque magnitude from the second motive power source, thereby adapting the system behavior to prevent opposite torque directions while maintaining motive power distribution capability when appropriate
Solution Approach 2:
The patent changes the operational parameter of the differential device from a fixed state to a variable state. By monitoring the torque parameter from the second motive power source and switching between differential operation and locked operation based on whether the torque exceeds a threshold, the system prevents opposite torque directions while preserving the ability to distribute motive power when conditions are favorable
2Reliability
If the differential effect is restricted when torque is low, then opposite torque directions are prevented, but the differential device cannot utilize its speed-adjusting capability
Solution Approach 1:
The system dynamically switches between locked and differential modes based on real-time torque conditions. When torque from the second motive power source exceeds the threshold, the differential device is locked to ensure torque direction stability. When torque is below the threshold, the differential device operates in differential mode, allowing speed adjustment and torque distribution. This dynamic adaptation resolves the contradiction between reliability and adaptability
3Reliability
If the engagement device is engaged to restrict differential effect, then torque directions are stabilized, but the device complexity increases
Solution Approach 1:
The patent introduces an engagement device as an intermediary mechanism between the differential device and the output shafts. This engagement device acts as a mediator that can selectively lock or unlock the differential mechanism based on torque conditions from the second motive power source, thereby stabilizing torque directions while providing a clear mechanical means to control the differential effect
Data Source
AI summary
A control apparatus for a motive power transmission device equipped with a first input shaft, a second input shaft to which a motive power from a motor is input, a rear wheel-side output shaft from which a motive power is output to a first driving wheel, a front wheel-side output shaft from which a motive power is output to a second driving wheel, and a planetary gear device that has, as three rotating elements, a sun gear to which the second input shaft is coupled, a carrier to which the front wheel-side output shaft is coupled, and a ring gear to which the first input shaft and the rear wheel-side output shaft are coupled engages an engagement device when a torque of the rear wheel-side output shaft is equal to or smaller than a threshold with the motor outputting the motive power.