Segmented Stator Cooling Oil Passages for Drive Motor Heat Management
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Solution Overview
Problem
Current cooling methods for drive motors in hybrid electric vehicles, such as indirect cooling, result in low cooling efficiency and inadequate cooling of coil connection portions, leading to reduced motor performance and potential damage due to heat generation.
Innovation Solution
A stator with a segmented core and a casing structure that allows for direct cooling of coils using cooling oil, while also indirectly cooling the coil connection portions through a passage system, enhancing overall cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If indirect cooling method is used, then cooling structure is simple, but cooling efficiency is low
Solution Approach 1:
The stator is divided into multiple segments, each with its own independent cooling chamber and cooling oil passage. This segmentation allows cooling oil to directly contact each coil segment separately, significantly improving cooling efficiency while maintaining structural simplicity through modular design
Solution Approach 2:
Cooling oil is introduced as an intermediary substance to transfer heat from the coils to the cooling chambers. The cooling oil circulates through passages in each segment, efficiently carrying away heat generated by the coils without requiring complex direct cooling structures
2Reliability
If oil-scatter cooling method is used, then certain areas are cooled, but cooling constancy cannot be maintained
Solution Approach 1:
The cooling oil passages are designed to continuously circulate cooling oil through each segment's cooling chamber, ensuring continuous and consistent heat removal from the coils. This continuous circulation maintains stable cooling performance regardless of driving conditions or vehicle inclination
Solution Approach 2:
Each segment is equipped with dedicated cooling chambers and passages tailored to the specific heat generation characteristics of that segment. The cooling structure is optimized locally for each segment, ensuring uniform cooling coverage and constant temperature control across all coil connection portions
3Length of stationary object
If indirect cooling is used, then heat transfer path is long, but cooling efficiency is low
Solution Approach 1:
The cooling chambers are extracted and integrated directly into each stator segment, removing the need for long external heat transfer paths. The cooling oil passages are positioned adjacent to the coils within each segment, extracting the heat source proximity function from the distant cooling system and placing it directly at the heat generation point
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 proposed stator design improves cooling efficiency, maintaining motor performance, increasing driving distance and high torque duration, and reducing material costs by effectively managing heat generation in drive motors.
Implementation Method 1
cooling oil flows in and out of the casing
Implementation Method 2
cooling oil flows in and out of the casing to enclose the coil
Data Source
AI summary
A stator for a drive motor includes: a segmented stator core including a plurality of mounting portions; a bobbin equipped on each mounting portion of the plurality of the mounting portions and having a coil wound thereon; a first casing and a second casing coupled to the bobbin, respectively, at opposite sides of the bobbin with respect to the segmented stator core, and configured to enclose the coil; a passage formed in one of the first casing or the second casing, and configured to allow fluid communication with the inside of the first casing and the second casing; and a terminal portion integrally formed in a remaining one of the first casing or the second casing and configured to allow connection of the coil.