Chain-Driven E-Drive Gearbox to Eliminate Axial Forces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric drive modules suffer from performance inefficiencies, increased weight, noise, vibration, and axial forces that require heavy bearings and complex lubrication systems, which affect fuel efficiency and size.
Innovation Solution
A chain-driven electric drive gearbox that eliminates axial forces, reduces bearing load, and incorporates a dry sump oiling system, using chains to interconnect gears and reduce the size and weight of the module while enhancing fuel efficiency and minimizing noise and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If reduction gearsets with helical gears are used to transfer torque between input and output shafts, then torque transfer capability is improved, but axial forces are generated that require bearings of increased load carrying capacity and lubrication flow, increasing device complexity and weight
Solution Approach 1:
The patent replaces the traditional helical gear mechanism with a chain-driven pulley system. Instead of using meshing helical gears that generate axial thrust forces, the invention uses chains connecting pulleys to transfer torque, eliminating the axial force component while maintaining efficient torque transfer between shafts
2Power
If traditional reduction gearsets are used in the electric drive module, then torque multiplication is achieved, but the module size and weight increase, affecting fuel efficiency
Solution Approach 1:
The patent substitutes the conventional heavy gear-based reduction system with a lighter chain and pulley mechanism. This mechanical substitution achieves the same torque multiplication function with significantly reduced weight, as chains and pulleys can be designed with less material while maintaining structural integrity and load-bearing capacity
Solution Approach 2:
The invention changes the fundamental operating parameters of the torque transmission system by using chain tension and pulley diameter ratios instead of gear tooth engagement. This parameter change allows for a more compact and lighter design while achieving the required reduction ratio and torque multiplication
3Power
If helical gears are used for torque transfer, then efficient power transmission is achieved, but noise and vibration are generated
Solution Approach 1:
The patent replaces the gear meshing system with a chain-driven system that operates without the tooth engagement noise and vibration characteristic of helical gears. The chain and pulley system provides smooth torque transfer with significantly reduced acoustic emissions and mechanical vibrations
4Reliability
If reduction gearsets with increased bearing load capacity are used to handle axial forces, then torque transfer reliability is improved, but device complexity and size increase
Solution Approach 1:
The patent eliminates the need for high-capacity thrust bearings and complex lubrication systems by replacing the helical gear system with a chain-driven system. This substitution maintains reliable torque transfer while dramatically simplifying the bearing and lubrication requirements, as chain drives do not generate axial thrust forces
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electric drive module (e-drive module) for an electric motor vehicle and chain driven electric-drive (e-drive) gearbox therefor is provided. The e-drive gearbox has first and second chain members operably coupling an output shaft of an electric motor to a shaft of a driven output member. A first drive gear is rotatable with the output shaft of the electric motor. A first driven gear is coupled to the first drive gear via the first chain member. A second driven gear is coupled to the first driven gear via a common shaft and co-rotatable with the first driven gear. A second drive gear is coupled to the second driven gear via the second chain member. The respective rotational axes of the first and second drive gears and the first and second driven gears are parallel to each other.