Multi-Axle Drive Train Torque Control via Dynamic Safety Value
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Solution Overview
Problem
The existing multi-axle drive train systems face inefficiencies in utilizing the full potential torque of the drive device due to the need to reduce maximum torque when the second axle's coefficient of friction is low, limiting the torque transmission to the first axle and resulting in suboptimal driving performance.
Innovation Solution
A method where the safety value for reducing the maximum torque is dynamically adjusted at drive start and throughout a specific period based on conditions such as wheel force, differential rotational speed, and torsional values, allowing for increased torque transmission when conditions permit, ensuring safe operation and maximizing the drive device's potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the maximum torque of the drive device is reduced by a safety value when the second axle is coupled to the drive device, then the first axle can transmit the torque without damage, but the driving performance and acceleration are limited
Solution Approach 1:
The patent applies dynamics by transitioning from a static, fixed safety value approach to a dynamic, time-varying safety value approach. The safety value is reduced over time after clutch engagement, allowing the system to adapt to changing mechanical conditions. This enables the drive device to progressively transmit more torque as the drivetrain components settle and engage properly, resolving the contradiction between maintaining safety and maximizing performance.
Solution Approach 2:
The patent changes the parameter of the safety value from a constant to a time-dependent variable. By reducing the safety value over time after clutch engagement, the system allows the maximum transmittable torque to increase progressively. This parameter change enables the drivetrain to operate safely during initial engagement while maximizing torque transmission potential during steady-state operation, thus resolving the contradiction between reliability and productivity.
2Productivity
If the entire torque from the drive device is transmitted to the first axle, then the torque utilization is maximized, but the rigid coupling may cause damage under high torque conditions
Solution Approach 1:
The patent applies beforehand cushioning by introducing a time-based protective mechanism. During the initial period after clutch engagement, a higher safety value acts as a cushion, limiting torque transmission to protect the rigidly coupled first axle from potential damage. As time progresses and the drivetrain stabilizes, the safety value is reduced, allowing fuller torque utilization without compromising component durability.
3Productivity
If the safety value is reduced over time after clutch engagement, then the full potential torque can be utilized, but the risk of damage increases if conditions change
Solution Approach 1:
The patent applies feedback by continuously monitoring the time since clutch engagement and adjusting the safety value accordingly. This time-based feedback mechanism ensures that as the drivetrain settles and proves its structural integrity, the system progressively allows higher torque transmission. The feedback loop maintains operational safety while enabling full torque potential to be realized during normal operation.
Data Source
AI summary
A device and a method for operating a multi-axle drive train for a vehicle. A first axle is operatively connected permanently and a second axle is operatively connected at least intermittently via a clutch to a drive device. For the second axle coupled to the drive device, a maximum torque of the drive device is reduced by a specific safety value. At drive start, the safety value is set to a specific initial value and subsequently is reduced or increased throughout a specific period of time.