Multi-Plate Lockable Differential for Torque Bias Without Driveline Damage
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Solution Overview
Problem
Conventional differential gears face challenges in maintaining power transmission and preventing driveline damage, especially when one wheel loses traction and the other wheel spins, leading to uneven torque distribution and potential damage during cornering.
Innovation Solution
A lockable differential gear design featuring a multi-plate clutch with inner and outer plates, where the bevel gear is supported by a contact surface on the differential basket, enabling a frictionless and wear-free rotational connection, and allowing for adjustable torque distribution between the wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is not actuated, then both wheels are driven with the same amount of torque, but one wheel will spin twice as fast as the differential basket when it loses traction, causing power loss
Solution Approach 1:
The differential gear allows dynamic torque distribution between wheels through the differential mechanism. When one wheel loses traction and spins faster, the differential automatically reduces torque to that wheel while maintaining torque to the other wheel, preventing complete power loss while accommodating speed differences.
2Reliability
If a lockable differential gear is used to prevent wheel spinning, then torque distribution is improved, but part of the power is converted into heat in the differential gear or clutch
Solution Approach 1:
The friction clutch provides partial locking action rather than complete rigid connection. This allows sufficient torque transfer to prevent wheel spinning while limiting the friction engagement to only what is necessary, thereby reducing power conversion to heat compared to full locking mechanisms.
3Reliability
If the full lock is used on good ground, then wheels turn at the same speed, but the driveline can become distorted and damaged due to tire slip in curves
Solution Approach 1:
The differential mechanism provides dynamic adaptation to driving conditions. On good ground, it allows wheels to turn at different speeds during cornering, preventing driveline distortion. The friction clutch only engages partially when necessary to prevent excessive wheel spin, avoiding the rigid constraints that cause driveline damage.
Solution Approach 2:
The friction clutch dynamically changes the torque distribution parameter between locked and unlocked states based on wheel slip conditions. This allows the system to transition from rigid torque equalization (which causes damage) to flexible torque distribution (which prevents damage) according to actual driving needs.
4Reliability
If a multi-plate clutch with ramp device is used, then torque distribution is improved, but the device complexity increases
Solution Approach 1:
The friction clutch integrates the torque distribution function directly into the differential gear assembly, merging the clutch mechanism with the existing differential structure. This eliminates the need for separate complex actuating devices and ramp mechanisms, achieving effective torque control while reducing overall device complexity.
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 effectively prevents power loss and driveline damage by ensuring consistent torque distribution between wheels, even when one wheel loses traction, while maintaining a compact and lightweight design.
Implementation Method 1
a multi-plate clutch with at least one inner plate and at least one outer plate for the switchable connection of a first output shaft with the differential basket
Implementation Method 2
the torque introduced is transmitted from a differential basket to gear wheels which are rotatably arranged in the differential basket and connected to each other via gear teeth
Data Source
AI summary
A differential gear for transmitting a torque to an axle of a motor vehicle including a differential basket, a bevel gear, first and second output shafts, and a multi-plate clutch. The bevel gear includes inner and outer circumferential surfaces. The bevel gear is supported by a contact surface of the differential basket with respect to a radial direction. The output shafts have a common rotary axis, the first output shaft forming a positive connection with the bevel gear with respect to a circumferential direction via a outer circumferential surface of the first output shaft and the inner circumferential surface of the bevel gear. The multi-plate clutch provides for selectively connecting the first output shaft with the differential basket and includes an inner plate carried by a section of the outer circumferential surface of the bevel gear and an outer plate carried by the differential basket.