Bridge Drive Shaft Oil Passage for Rotor Cooling
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Solution Overview
Problem
The existing bridge drive system in electric vehicles has poor cooling performance due to the separation of oil flow between the motor and speed reduction mechanism, limiting motor performance and increasing heat resistance requirements.
Innovation Solution
A novel bridge drive system design that includes a housing with separated spaces for the motor and speed reduction mechanism, a shaft assembly with an oil inlet and outlet, and components like an oil collecting and guide component to facilitate oil flow from the speed reduction mechanism to the motor, forming a cooling mechanism within the shaft assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a partition wall is formed between blind holes in the rotating shaft to prevent oil flow from the speed reduction mechanism to the motor, then oil leakage is prevented, but cooling performance deteriorates
Solution Approach 1:
The rotating shaft is segmented into multiple functional zones: a first blind hole for oil storage, a partition wall for isolation, and a second blind hole for cooling. This segmentation allows the shaft to simultaneously prevent oil leakage to the motor while enabling dedicated cooling oil flow to the rotor through the second blind hole.
Solution Approach 2:
The partition wall acts as an intermediary element that separates the oil storage function from the cooling function. It prevents oil from the first blind hole from reaching the motor while allowing a separate cooling oil path through the second blind hole to cool the rotor effectively.
2Temperature
If the partition wall is moved towards the motor side to enable oil flow to the rotor, then cooling performance improves, but the shaft wall becomes too thick
Solution Approach 1:
Instead of moving the partition wall and thickening the shaft, the invention segments the shaft into multiple blind holes at different positions. The first blind hole stores oil, the partition wall isolates it, and the second blind hole provides a dedicated cooling path to the rotor, avoiding the need for excessive wall thickness.
3Weight of moving object
If blind holes are provided in the rotating shaft to reduce weight, then shaft weight decreases, but cooling performance deteriorates due to oil flow separation
Solution Approach 1:
The shaft uses blind holes to maintain weight reduction while improving cooling through segmentation. The first blind hole stores oil and the second blind hole specifically channels cooling oil to the rotor, ensuring both weight efficiency and effective cooling performance.
Solution Approach 2:
The partition wall serves as an intermediary that directs cooling oil from the first blind hole through the shaft structure to the second blind hole, which then delivers oil to the rotor. This intermediary mechanism enables cooling function while maintaining the weight benefits of blind hole design.
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 design enhances the cooling performance of the motor by circulating oil to the rotor, thereby improving motor performance and reducing heat resistance requirements.
Implementation Method 1
an oil passage extending from the oil inlet into the first space and then returning to the oil outlet is formed inside the shaft assembly, so that oil from the second space can flow from the oil inlet into the oil passage to cool the rotor
Data Source
AI summary
A bridge drive system, including a housing, a motor, a speed reduction mechanism, and a shaft assembly. The housing has first and second spaces separated from each other. The motor is in the first space, and the speed reduction mechanism is in the second space. The shaft assembly has an oil inlet and an oil outlet which are both located in the second space. An oil passage extending from the oil inlet into the first space and then returning to the oil outlet is formed inside the shaft assembly so that oil from the second space can flow from the oil inlet into the oil passage to cool a rotor and then return to the second space from the oil outlet. In this way, the cooling performance of a motor is improved, improving its performance and reducing heat resistance requirements of each component.