Vehicle Torque Control for Bearing Load Reduction
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Solution Overview
Problem
Existing vehicle control devices do not adequately differentiate between the maximum torque requirements for forward and rearward vehicle travel, leading to uneven loading on bearings in the drive unit, which can shorten their lifespan.
Innovation Solution
A vehicle control device that calculates torque command values based on a map considering the front-rear weight distribution of the vehicle, allowing different maximum torque values for forward and rearward travel to optimize torque generation and reduce bearing load, with the ability to adjust torque restriction values dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same maximum torque value is used for both forward and rearward travel, then the vehicle control is simplified, but the bearing load increases unevenly reducing component life
Solution Approach 1:
The patent applies dynamics by making the maximum torque value adjustable based on travel direction. The control device dynamically switches between a first maximum torque value for forward travel and a second maximum torque value for rearward travel, allowing the torque parameter to adapt to different operational conditions rather than remaining static
Solution Approach 2:
The patent changes the torque parameter based on travel direction. By detecting whether the vehicle is moving forward or rearward, the control device adjusts the maximum torque value accordingly - using a higher value for forward travel and a lower value for rearward travel, thus optimizing both performance and component life
2Duration of action of stationary object
If the maximum torque value is reduced for rearward travel, then bearing load is reduced extending component life, but vehicle propulsion capability may be limited
Solution Approach 1:
The patent applies local quality by differentiating torque limits for different operational contexts (forward vs. rearward travel). Instead of applying a uniform torque limit, the system assigns appropriate torque characteristics to each travel direction based on the specific demands and bearing load conditions of that direction
3Duration of action of stationary object
If different maximum torque values are set for forward and rearward travel, then bearing load is optimized for extended life, but the control system becomes more complex
Solution Approach 1:
The control system dynamically adjusts torque values based on travel direction detection, switching between predetermined torque limits rather than using a static control approach
Solution Approach 2:
The control device performs multiple functions: it detects travel direction, determines the appropriate maximum torque value based on that direction, and controls the motor accordingly. This multi-functional approach consolidates the complexity into a single control unit that handles both direction detection and torque management
Data Source
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AI summary
A vehicle control device 30 controls torque of a drive motor 11 such that rotation of the drive motor 11 is transferred to rear drive wheels 15 of a vehicle via a drive unit 20 that includes a speed reducer 12 including a plurality of gears rotatably supported by bearings. The vehicle control device 30 sets different values as torque restriction values for torque to be generated by the drive motor 11 when the vehicle is driven forward and when the vehicle is driven rearward.