Torque Vectoring Differential with Axle Disconnect Mechanism
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Solution Overview
Problem
Conventional differential assemblies with torque vectoring and axle connect/disconnect mechanisms are engineered to handle large torque loads, leading to inefficiencies in fuel economy due to parasitic losses from spinning and friction in secondary drivelines during reduced acceleration.
Innovation Solution
A differential assembly with a torque coupling unit and axle disconnect mechanism, featuring a pinion shaft, differential ring gear, clutch plates, and actuation mechanisms that selectively engage and disengage clutch packs to manage torque and reduce spinning losses by disconnecting secondary drivelines when not needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the differential assembly is engineered to handle large torque loads, then the torque capacity is improved, but the fuel economy deteriorates due to parasitic losses from spinning and friction in secondary drivelines during reduced acceleration
Solution Approach 1:
The patent implements a dynamic axle connect/disconnect mechanism that allows the secondary driveline to be selectively engaged or disengaged based on vehicle operating conditions. During high torque demands, the axle remains connected; during low acceleration conditions, the axle disconnects to eliminate parasitic losses. This dynamic adjustment resolves the contradiction by adapting the system configuration to match actual torque requirements rather than maintaining a fixed design for maximum torque capacity.
Solution Approach 2:
The differential assembly is segmented into separate connectable/disconnectable components, specifically the secondary driveline elements that can be isolated from the power flow. The clutch mechanism divides the drivetrain into active and inactive segments, allowing the secondary driveline to be disconnected when not needed, thereby eliminating energy losses while maintaining the capability to handle large torque loads when required.
2Ease of operation
If the secondary drivelines continue to rotate during reduced acceleration, then the driveline connectivity is maintained, but energy losses increase due to oil churning and spinning losses
Solution Approach 1:
The system dynamically adjusts driveline connectivity based on vehicle acceleration and torque demands. The clutch mechanism monitors operating conditions and automatically disconnects the secondary driveline during low-acceleration phases, preventing unnecessary rotation and eliminating oil churning losses. During high-acceleration phases, the driveline reconnects to maintain proper operation, thus dynamically optimizing both energy efficiency and operational readiness.
Solution Approach 2:
The axle connect/disconnect mechanism operates periodically based on vehicle operating cycles. The system alternates between connected and disconnected states according to acceleration demands, engaging the secondary driveline during high-torque periods and disengaging during low-torque periods. This periodic action eliminates energy losses during unnecessary rotation while maintaining driveline connectivity when needed for proper vehicle operation.
3Reliability
If a torque vectoring mechanism is used to limit torque flow, then traction control is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the torque vectoring function from a complex active control mechanism and replaces it with a simpler mechanical disconnect feature. Instead of using sophisticated sensors, actuators, and control systems to actively limit torque flow, the invention simply disconnects the secondary driveline when torque demands are low, achieving effective torque vectoring through physical separation rather than active control. This dramatically reduces device complexity while maintaining reliable traction control.
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
This design reduces spinning and friction losses, enhancing fuel efficiency by allowing selective connection and disconnection of secondary drivelines, thereby improving overall vehicle efficiency during varying traction conditions.
Implementation Method 1
The first and the second plurality of clutch plates form a clutch pack of the torque coupling unit... applying a force to an end of the one or more thrust pins causing the first and the second plurality of clutch plates to be at least variably frictionally engaged with the clutch can
Data Source
AI summary
A differential assembly having a torque coupling unit and an axle disconnect. A first end portion of an intermediate portion of a differential case is integrally connected to a ring gear. Integrally connected to an inner surface of the intermediate portion of the case is a first plurality of clutch plates. Disposed within a hollow portion of the intermediate portion is a first and a second differential side gear that are meshing with one or more pinion gears. Drivingly connected to the first side gear is a first output shaft. A clutch can having a second plurality of clutch plates is drivingly connected to the first output shaft. Within the hollow portion of the intermediate portion of the case is a clutching assembly that selectively engages the second side gear. A first clutch actuator selectively engages the plurality of plates and a second clutch actuator selectively engages the clutching assembly.