E-Axle Transmission Cooling Flow Path With Rib-Sealed Inner Cylinder
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Solution Overview
Problem
The existing transmission mechanisms for e-axle drive systems in electric vehicles require high processing precision and involve complex, time-consuming assembly processes due to interference fits between the inner cylinder and shaft assembly components, which complicates the cooling flow path for motor rotors.
Innovation Solution
A transmission mechanism with a cooling flow path is designed, featuring a shaft assembly with a shaft hole and discharge hole, and an inner cylinder with annular rib portions that seal gaps without interference fit, allowing for a simplified assembly process and reduced processing precision, enabling efficient cooling medium flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interference fit is used between the inner cylinder and shaft assembly components to seal gaps, then sealing reliability is improved, but manufacturing precision requirements increase and assembly complexity increases
Solution Approach 1:
The inner cylinder is divided into multiple circumferential portions (first circumferential portion and second circumferential portion) that are assembled separately. Each portion has rib portions that seal against the shaft assembly independently, distributing the sealing function across multiple segments rather than requiring a single precision-fit component.
Solution Approach 2:
The rib portions formed on the inner cylinder serve as intermediary sealing elements between the inner cylinder and the shaft assembly. These rib portions abut against the shaft assembly to seal gaps, replacing the need for high-precision interference fit between the entire inner cylinder and shaft assembly components.
2Reliability
If interference fit is used between the inner cylinder and shaft assembly components, then sealing reliability is improved, but assembly time increases
Solution Approach 1:
The inner cylinder is segmented into multiple circumferential portions that can be assembled independently. This segmentation allows for simpler, faster assembly of each portion against the shaft assembly using rib portions, rather than requiring time-consuming precision alignment and fitting of a complete inner cylinder.
Solution Approach 2:
The rib portions act as intermediary elements that simplify the assembly process. By providing predetermined abutting surfaces on the rib portions, the assembly operation becomes more straightforward and requires less time compared to achieving precise interference fit of the entire inner cylinder.
3Manufacturing precision
If high processing precision is required for the inner cylinder and shaft assembly, then sealing performance is improved, but device complexity increases
Solution Approach 1:
Dividing the inner cylinder into multiple circumferential portions with integrated rib portions reduces assembly complexity. Each portion can be manufactured and assembled independently, simplifying the overall assembly process compared to manufacturing and assembling a single complex inner cylinder requiring high precision interference fit.
Solution Approach 2:
The rib portions provide localized sealing quality at specific interfaces between the inner cylinder and shaft assembly. This localized approach to sealing simplifies the overall device structure by concentrating sealing functions at specific rib portions rather than requiring high precision throughout the entire inner cylinder assembly.
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 solution reduces processing precision requirements and simplifies the assembly process while maintaining effective cooling, thereby shortening assembly time and improving heat dissipation capacity in e-axle drive systems.
Implementation Method 1
one or more first annular rib portions are formed on the outer circumferential wall of the inner cylinder at one axial end portion, the one or more first annular rib portions abut against the inner circumferential wall of the shaft assembly, to seal a gap between the one axial end portion of the inner cylinder and the shaft assembly
Implementation Method 2
the central hole is in communication with the intermediate space through the communication hole, so that a cooling medium entering from the inlet is discharged out of the shaft assembly through the central hole, the communication hole, the intermediate space and the discharge hole
Implementation Method 3
In order to cool the rotor of the motor, oil at a position where the transmission is located can be transmitted to a position where the rotor of the motor is located via the shaft assembly for cooling
Implementation Method 4
a cooling medium entering from the inlet is discharged out of the shaft assembly through the central hole, the communication hole, the intermediate space and the discharge hole
Data Source
AI summary
A transmission mechanism having a cooling flow path, the transmission mechanism comprising a shaft assembly and an inner cylinder. A first annular rib portion is formed on an outer peripheral wall of one axial end of the inner cylinder to close a gap between the axial end of the inner cylinder and the shaft assembly, and a second annular rib portion is formed on an outer peripheral wall of the other axial end of the inner cylinder to close a gap between the other axial end of the inner cylinder and the shaft assembly, such that a cooling medium entering from an inlet of the shaft assembly can flow through a central hole, a communication hole, an intermediate space and a discharge hole to be discharged to the outside of the shaft assembly. An electric bridge drive system including the transmission mechanism.