Coaxial Left-Right Wheel Drive Layout for Compact Torque Split
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Solution Overview
Problem
Existing vehicle wheel driving devices face challenges in achieving a compact design while maintaining sufficient torque difference transmission between left and right wheels, often resulting in increased size due to long power transmission paths and reduced rotation speed from single gear trains.
Innovation Solution
A left-right wheel driving device with coaxially disposed motor shafts, parallel counter shafts, and output shafts featuring a reduction gear train and a gear mechanism that amplifies torque difference, allowing for a compact configuration by positioning components efficiently and overlapping gears to reduce vehicle width dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single gear train is used to reduce motor rotation speed, then the device size is reduced, but the torque difference transmission capability is insufficient
Solution Approach 1:
The patent combines two functions into a single integrated gear mechanism: (1) a reduction gear train that reduces motor rotation speed, and (2) a torque difference amplification mechanism that transmits amplified torque to the wheels. This merging allows the device to achieve both compact size and sufficient torque transmission capability without requiring separate mechanisms.
Solution Approach 2:
The gear mechanism is designed to perform multiple functions simultaneously: it reduces rotation speed from the motors, amplifies the torque difference between left and right sides, and transmits the resulting torques to the corresponding wheels. This multi-functionality eliminates the need for additional dedicated mechanisms, maintaining compact dimensions while ensuring adequate torque transmission.
2Length of moving object
If motors are arranged on the vehicle shaft, then power transmission is direct, but the device dimension in vehicle width direction increases
Solution Approach 1:
Instead of arranging motors on the vehicle shaft (width direction), the patent positions the motors above the vehicle shaft and uses vertically extending shafts (motor shafts, counter shafts, output shafts) to transmit power. This dimensional reorganization moves the power transmission path from the horizontal plane to the vertical plane, reducing the device's width while maintaining efficient power transmission.
Solution Approach 2:
The patent employs a nested arrangement where the counter shafts are positioned within the space between the left and right motors, and the output shafts are arranged to overlap with the motor assemblies in the vertical direction. This nesting allows multiple transmission components to occupy overlapping spatial envelopes, minimizing the overall device footprint in the vehicle width direction.
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
The solution enables a compact driving device that reduces motor rotation speed and amplifies torque difference, achieving a more compact size and improved torque transmission efficiency.
Implementation Method 1
motor shafts that are positioned between the rotating shafts coaxially with the rotating shafts and that are each provided with a motor gear, counter shafts that are disposed in parallel to the motor shafts and that are each provided with a first intermediate gear meshing with the motor gear and a second intermediate gear having a diameter smaller than that of the first intermediate gear
Implementation Method 2
a reduction gear train that reduces the rotation speed of the motors and a gear mechanism that amplifies a torque difference between the two motors
Data Source
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AI summary
In a left-right wheel driving device (10) including two motors (1, 2) that drive left and right wheels and a gear mechanism (3) that amplifies a torque difference between the two motors (1, 2) and transmits the amplified torques to the left and right wheels, respective, rotating shafts (1A, 2A) of the two motors (1, 2) are coaxially disposed. The left-right wheel driving device (10) further includes motor shafts (11) that are positioned between the rotating shafts (1A, 2A) coaxially with the rotating shafts (1A, 2A) and that are each provided with a motor gear (21), counter shafts (12) that are disposed in parallel to the motor shafts (11) and that are each provided with a first intermediate gear (22) meshing with the motor gear (21) and a second intermediate gear (23) having a diameter smaller than that of the first intermediate gear (22), and output shafts (13) that are disposed in parallel to the motor shafts (11) and that are each provided with an output gear (24) meshing with the second intermediate gear(23). The gear mechanism (3) is disposed on one end side of each of the output shafts (13) and one of the left and right wheels is disposed on the other end side of the output shaft (13).