Locking Differential Assembly With Axial Actuation for Compact Packaging
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Solution Overview
Problem
Conventional differential units in vehicles are bulky, limiting their implementation in vehicles with independent wheel suspension configurations due to size constraints, and existing locking systems cause friction, wear, and assembly complexity, especially when high torque is required.
Innovation Solution
A locking differential assembly with a blocking member and actuation system that occupies less space, uses a small-sized fork-shaped element, minimizes friction, and maintains a conventional dog clutch case profile, allowing integration in vehicles with independent wheel suspension without wheel reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional blocking system is used at one end area of the differential unit, then the differential can be blocked to transfer torque to the gripping wheel, but the transverse width of the vehicle increases beyond regulatory requirements
Solution Approach 1:
The blocking system is repositioned from a transverse arrangement (at one end area) to a longitudinal arrangement (inside the differential housing along the rotational axis). The actuation ring moves axially within the differential housing to engage/disengage the dog clutch, eliminating the need for transverse space while maintaining blocking functionality
Solution Approach 2:
The actuation ring is received within the differential housing, and the dog clutch is nested within the differential mechanism. The connecting pins pass through the differential housing to connect the actuation ring to the dog clutch, allowing compact integration of multiple components within the existing differential housing boundaries
2Reliability
If a large-sized fork is used to move the actuating ring, then the blocking system can function, but the radial dimension of the differential housing increases
Solution Approach 1:
Instead of using a large fork to push the actuation ring radially, the invention uses a compact actuation ring that moves axially within the differential housing. The connecting pins transfer motion from the dog clutch to the actuation ring in reverse direction, enabling compact radial dimensions while maintaining blocking functionality
3Reliability
If a large contact area between the actuating ring and fork is used, then the blocking system can be actuated, but friction increases leading to losses and wear
Solution Approach 1:
The large fork component is completely removed from the design. Instead, small connecting pins are used to transfer motion between the dog clutch and actuation ring, dramatically reducing the contact area and friction losses while maintaining reliable actuation of the blocking system
4Ease of manufacture
If the dog clutch case hardening profile is modified to accommodate the large fork, then assembly can proceed, but crack initiation occurs during case hardening
Solution Approach 1:
The large fork is replaced with simple connecting pins that do not require complex case hardening profiles. The connecting pins are smaller, simpler components that can be manufactured and assembled without risking crack initiation, effectively replacing a problematic component with a simpler, more reliable alternative
5Reliability
If a conventional blocking system is used, then torque can be blocked, but the device complexity increases
Solution Approach 1:
The blocking system components (actuation ring, dog clutch, connecting pins) are integrated within the existing differential housing and mechanism. The actuation ring combines the functions of a actuator and a locking mechanism, while the connecting pins serve both as motion transfer elements and structural connectors, reducing overall system complexity compared to conventional separate blocking systems
Data Source
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AI summary
The invention relates to an assembly (110) for a differential unit (10) of a vehicle (1), comprising: - a differential housing (24a, 24b) having a longitudinal axis (23), the differential housing (24a, 24b) being provided with a plurality of through-holes (25) formed therein; - a differential side gear (18) configured to be connected to a drive shaft (11) capable of being connected to a wheel of a vehicle, the differential side gear (18) being located inside the differential housing (24a) and being rotatably mounted relative to the differential housing (24a) around the longitudinal axis (23); - a blocking system (100) for blocking the differential unit (10) operation, comprising : • a blocking member (30) movable between a released position and a blocking position, and • an actuation system (50) for moving the blocking member (30) between said released and blocking positions.