Axle Assembly Reverser Mechanism for Spin Turn Steering
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Solution Overview
Problem
Conventional vehicles with longer wheelbases face challenges in achieving a tight turning circle and spin turn capability due to mechanical complexity and excessive weight, particularly when trying to replicate the skid steering mechanism which results in tyre wear and scrubbing.
Innovation Solution
An axle assembly featuring a differential gear with a reverser mechanism, including an epicyclic gear assembly, allows each wheel hub to be driven in the same or opposite direction, enabling spin steer configuration through a steering controller that manages wheel positions and actuator control, reducing mechanical complexity and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If skid steering mechanism is used to achieve tight turning circle, then turning capability is improved, but tyre wear and scrubbing increase
Solution Approach 1:
Instead of skid steering where wheels slide laterally causing scrubbing, the invention uses pivot steering where wheels rotate about a vertical axis through their centers. This inverts the steering mechanism from lateral sliding to rotational pivoting, eliminating tyre scrubbing while achieving tight turning circles.
Solution Approach 2:
The invention replaces the complex mechanical spin turn mechanism (requiring wheel pivots and differential drives) with a simpler system using inboard wheel rotation. The wheels are rotated about their own centers by the reverser mechanism rather than pivoting the entire wheel assembly, simplifying the mechanical system while achieving the same turning effect.
2Speed
If spin turn capability is provided for longer-wheel based vehicles, then turning circle is improved, but mechanical complexity increases
Solution Approach 1:
The invention extracts the wheel rotation function from the complex spin turn mechanism. Instead of requiring wheel pivots and complex differential drives, the reverser mechanism directly rotates the wheels about their centers. This separates the rotation function from the pivoting function, simplifying the overall mechanical system.
Solution Approach 2:
The reverser mechanism serves multiple functions: it enables both forward and reverse wheel rotation, provides spin turn capability, and allows tight turning circles. This multi-functionality eliminates the need for separate mechanisms for each function, reducing overall mechanical complexity.
3Speed
If spin turn capability is provided for longer-wheel based vehicles, then turning circle is improved, but vehicle weight increases
Solution Approach 1:
The invention removes the heavy components associated with traditional spin turn mechanisms, such as wheel pivots and complex differential drives. The reverser mechanism uses a compact epicyclic gear assembly that is significantly lighter than the alternative mechanisms, reducing overall vehicle weight.
Solution Approach 2:
The invention uses a simplified version of the spin turn effect achieved through inboard wheel rotation rather than full wheel pivoting. This copied effect achieves the same functional outcome (tight turning circle) with significantly reduced mechanical complexity and weight.
4Speed
If wheels are driven in opposite directions for spin turn, then turning capability is improved, but drive transmission complexity increases
Solution Approach 1:
The invention merges the differential drive function with the reverser mechanism into a single integrated epicyclic gear assembly. This combines the functions of differential drive (enabling opposite rotation) and reverser mechanism (enabling bidirectional rotation) into one compact unit, simplifying the drive transmission system.
Solution Approach 2:
The epicyclic gear assembly serves multiple functions simultaneously: it provides differential drive for opposite wheel rotation, enables reverser operation for bidirectional rotation, and transmits power from the drive shaft. This multi-functionality eliminates the need for separate mechanisms, reducing drive transmission 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
Enables vehicles to achieve a tight turning circle with minimal tyre wear and scrubbing by allowing wheels to pivot and rotate in opposite directions, simplifying the mechanical configuration and reducing weight, while maintaining efficient drive transmission.
Implementation Method 1
The reverser mechanism may comprise an epicyclic gear assembly
Data Source
AI summary
An axle assembly for a vehicle, the axle assembly comprising a differential gear having an input for connection to a drive shaft, and a first wheel hub to support a first wheel and a second wheel hub to support a second wheel, the first wheel hub and the second wheel hub being drivingly connected to the differential gear, wherein the first wheel hub is drivingly connected to the differential gear via a reverser mechanism, the reverser mechanism having a first operating mode where the first wheel hub is driven in the same direction as the second wheel hub and a second operating mode where the first wheel hub is driven in the opposite direction to the second wheel hub.