Motor Housing Coolant Passage Layout for Compact Stator Cooling
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Solution Overview
Problem
Existing motor units are large in size due to the radial arrangement of oil passages outside water passages, which hinders compact design and uniform holding force distribution.
Innovation Solution
The motor unit design arranges water and oil passages in the peripheral direction, with equal intervals and cross-sectional shapes, allowing for a reduced radial extent of oil passages and uniform holding force, enabling direct stator cooling and lubrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entirety of the oil passage is disposed radially outward of the water passage, then the water and oil passages can be clearly separated, but the motor unit size increases
Solution Approach 1:
The patent transitions from a purely radial arrangement to a hybrid arrangement where oil passages are positioned both radially outward and peripherally adjacent to water passages. This dimensional change in passage positioning allows for compact motor unit design while maintaining functional separation of cooling systems
2Device complexity
If the oil passage is arranged radially outward of the water passage, then the passage layout is simplified, but the holding force uniformity deteriorates
Solution Approach 1:
The patent applies different arrangement strategies to different regions: radially outward positioning in some areas and peripheral positioning in others. This localized variation in passage arrangement maintains structural balance and uniform holding force while simplifying the overall layout design
3Reliability
If the water and oil passages are arranged at different radial positions, then the cooling paths are distinct, but the housing rigidity becomes non-uniform
Solution Approach 1:
The patent employs asymmetric passage positioning where oil passages are arranged both radially outward and peripherally adjacent to water passages. This asymmetric yet balanced arrangement maintains distinct cooling paths while preserving uniform housing rigidity through strategic positioning
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 configuration achieves a downsized motor unit with uniform holding force and efficient cooling, utilizing oil as both coolant and lubricant, while facilitating easy assembly and coolant recovery.
Implementation Method 1
a motor housed in the housing is cooled by the aqueous coolant flowing through the water passage
Implementation Method 2
the stator in the housing can be cooled directly by the oil-based coolant inside the housing
Implementation Method 3
the oil-based coolant supplied to the stator can also function as a lubricant
Data Source
AI summary
The motor unit includes a stator having a tubular shape centered on a central axis, a housing including a peripheral wall that holds the stator from a radially outer side, one or more water passages provided in the peripheral wall of the housing, with each of the one or more water passages extending along an axial direction parallel to the central axis and allowing aqueous coolant to flow, and one or more oil passages provided in the peripheral wall of the housing, with each of the one or more oil passages extending along the axial direction and allowing oil-based coolant to flow. The one or more water passages and the one or more oil passages are arranged along a peripheral direction.