Differential Locking Unit With Planetary Gears for Cornering Traction
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Solution Overview
Problem
Conventional differential transmissions lack the ability to effectively distribute torque between wheels during cornering on slippery or uneven surfaces, leading to reduced traction and stability, as they do not allow for simultaneous rotational speed differences between the wheels.
Innovation Solution
A transmission system with integrated differential locking unit, comprising two planetary gear sets and a differential locking unit, which includes an epicyclic transmission and a shift element, allowing for torque conversion and distribution while enabling differential locking by synchronizing output shafts during straight-ahead travel and locking action during other conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an open differential is used to allow different rotational speeds of drive wheels during cornering, then cornering ability is improved, but traction on slippery surfaces deteriorates because the wheel with better grip only has as much traction as the wheel on slippery ground
Solution Approach 1:
The differential locking unit dynamically adjusts the connection between drive wheels based on operating conditions. During cornering, the clutch plates allow relative movement maintaining different rotational speeds. During acceleration on slippery surfaces, the centrifugal force presses clutch plates together to create a locking effect, ensuring both wheels receive equal torque and improving traction.
Solution Approach 2:
The differential locking unit changes the torque distribution parameter between drive wheels based on operating conditions. The centrifugal clutch mechanism changes the effective gear ratio and torque split dynamically - from open differential behavior during cornering to locked differential behavior during acceleration, resolving the contradiction between cornering ability and traction.
2Device complexity
If a conventional differential transmission is used, then the structure remains simple, but the ability to distribute torque effectively between wheels during cornering on slippery surfaces deteriorates
Solution Approach 1:
The differential locking unit merges the functions of open differential and locked differential into a single transmission system. The planetary gear set combined with centrifugal clutch creates a unified mechanism that automatically switches between differential and locked modes, improving torque distribution on slippery surfaces without requiring separate differential units for each wheel.
Solution Approach 2:
The centrifugal clutch mechanism is self-actuating based on rotational speed. During acceleration on slippery surfaces, the centrifugal force automatically engages the clutch plates to lock the differential, without requiring external control systems or complex sensors, maintaining simplicity while improving torque distribution reliability.
3Reliability
If a differential lock is used to increase traction by partially connecting drive wheels, then traction is improved, but cornering ability deteriorates compared to an open differential
Solution Approach 1:
The differential locking unit provides dynamic torque distribution that adapts to operating conditions. During cornering, the reduced centrifugal force allows clutch plates to slip, maintaining open differential behavior for smooth cornering. During acceleration on slippery surfaces, increased centrifugal force engages the clutch to provide locking action for improved traction, resolving the contradiction between traction and cornering ability.
Data Source
AI summary
A transmission with a differential locking unit which comprises an input shaft (10), first and second output shafts (11, 12), and first and second planetary gear sets (P1, P2). Torque introduced, via the input shaft (10), is converted and distributed to the two output shafts (11, 12) in a defined ratio, and development of a sum torque is prevented. The differential locking unit comprises an epicyclic gearing (P3) as well as a switching element (B 1). The epicyclic gearing (P3) has at least three connection shafts (3), a first connection shaft (WI) is rotationally fixed to a linking shaft (3), a second connection shaft (W2) is rotationally fixed to the second element (E21) of the first planetary gear set (PI), which is rotationally fixed to the first output shaft (11). A third connection shaft (W3) can be secured to a rotationally fixed component (GG) by the switching element (B 1).