Cross-Steer Drive with Differential Power Transfer for Vehicles
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Solution Overview
Problem
Existing drive systems for wheeled or track laying vehicles face inefficiencies in steering, either requiring separate motors and gearing for efficient steering or using dual independent motors that are not versatile for both propulsion and steering, leading to added weight or energy loss.
Innovation Solution
An electro-mechanical cross-steer device with a pair of motors, output planetary gear sets, and a differential mechanism that allows equal or unequal speed conditioning between motors to achieve straight-line movement and efficient steering without dissipating braking energy as heat, utilizing transfer gear assemblies and a center differential to manage torque and speed ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate electric motors and mechanical transmission systems are used for each track, then the vehicle can be propelled and steered, but the system weight increases and steering efficiency decreases due to power absorption losses
Solution Approach 1:
The patent merges the propulsion and steering functions into a single integrated drive system where a center differential connects both track drive systems, allowing one motor to serve dual purposes while the other handles auxiliary functions, thereby reducing overall system weight while maintaining steering efficiency through power transfer rather than absorption
2Ease of operation
If a gear assembly with one motor providing linear traction and a second motor providing steering overlaying power is used, then steering efficiency improves through power transfer, but the system complexity increases with separate motors for each function
Solution Approach 1:
The patent implements multi-functionality by enabling the first motor to alternate between providing linear traction and providing steering overlaying power through the center differential mechanism, allowing a single motor to perform multiple functions and reducing the need for separate dedicated motors for each function
3Loss of energy
If the inside track motor becomes a generator during steering, then energy loss is reduced compared to braking, but energy must be converted back to mechanical power at the outside track motor
Solution Approach 1:
The center differential acts as an intermediary mechanical power transfer device that directly couples the two track drive systems, allowing power to be transferred from the inside track (acting as generator) to the outside track through mechanical gearing rather than through electrical conversion cycles, thereby simplifying the power conversion process while maintaining energy efficiency
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 efficient steering by regeneratively transferring braking energy, reducing weight and energy loss, and allowing the same motors to handle both propulsion and steering functions, enhancing the vehicle's maneuverability and operational efficiency.
Implementation Method 1
first and second output planetary gear sets, each having a transfer gear assembly mechanically connected to the first and second motors
Implementation Method 2
a differential which is mechanically connected to the first and second output planetary gear sets via a mainshaft
Data Source
AI summary
According to the present invention there is provided an electro-mechanical cross-steer device for a vehicle. The device may include a first and a second motor and first and second output planetary gear set, each having a transfer gear assembly mechanically connected to the first and second motors, respectively. Additionally, a differential may be included which is mechanically connected to the first and second output planetary gear sets via a mainshaft connected to the first and second output planetary gear sets. First and second input shafts may be mechanically connected to the first and second transfer gear assemblies and to the differential. First and second output shafts may be respectively connected to the first and second output planetary gear sets with each of the output shafts operable to drive a particular side of a vehicle.