Motor Coolant Branching Layout for Uniform Cooling Flow

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Solution Overview

Problem

Existing motor units face issues with uneven cooling capacity and pressure loss due to differences in path lengths between coolant channels, leading to inefficient cooling and the need for larger pumping systems.

Innovation Solution

The motor unit design includes a coolant channel configuration with a branching passage where the distance between the inlet port and the first outlet port is shorter than that to the second outlet port, and the first outlet port has a larger area, ensuring a higher flow rate in the longer channel to balance cooling capacity and reduce pressure loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coolant channel has equal path lengths between first and second channels, then the pressure loss is balanced, but the cooling capacity becomes insufficient for the first channel which requires longer path length

Engineering Contradiction:
Improvecooling capacity balanceVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by making the first outlet port larger than the second outlet port to compensate for the longer path length of the first channel. This localized modification creates different flow characteristics at different locations to achieve overall balance in cooling capacity while maintaining acceptable pressure loss distribution.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the parameter of outlet port area to resolve the contradiction. By increasing the area of the first outlet port relative to the second outlet port, the system compensates for the longer path length and higher pressure loss in the first channel, thereby balancing the cooling capacity without requiring equal path lengths.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the first channel has longer path length for better cooling coverage, then the cooling capacity increases, but the pressure loss increases

Engineering Contradiction:
Improvecooling capacityVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent compensates for the increased pressure loss in the longer first channel by providing a larger first outlet port area. This localized adjustment reduces the flow resistance at the outlet, allowing the longer path to maintain adequate flow rate and cooling capacity without excessive pressure loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the outlet port area parameter to offset the negative effect of increased path length. By making the first outlet port larger, the system reduces the pressure loss in the longer first channel, enabling extended cooling coverage while maintaining energy efficiency.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If the outlet port areas are equal between first and second channels, then the manufacturing is simplified, but the flow rate distribution becomes uneven

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidflow rate balance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by making the first outlet port larger than the second outlet port. This localized differentiation compensates for the longer path length in the first channel, ensuring proper flow rate distribution while remaining relatively simple to manufacture by adjusting only the outlet port dimensions.

Inventive Principle:
Principle #3Local quality

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 achieves uniform cooling of the motor by adjusting coolant flow rates and reducing pressure loss, preventing the need for oversized pumps and minimizing manufacturing costs while improving yield.

Implementation Method 1

a coolant channel that is provided in a wall face of the housing and that is configured such that a coolant flows through

Methodology Applied
Scientific EffectFluid flow:

Data Source

PatentEP4583377A1Motor unit
Publication Date: 2025.07.09 TOYOTA JIDOSHA KK
  • EP4583377A1 patent drawingFigure 1
  • EP4583377A1 patent drawingFigure 2
  • EP4583377A1 patent drawingFigure 3

AI summary

A motor unit (1) includes a motor (2), a housing (30), and a coolant channel (40) that is configured such that a coolant flows through. The coolant channel (40) includes an inlet passage (41) for receiving the coolant from outside, a branching passage (42) into which the coolant flows from the inlet passage (41), a first channel (43) into which the coolant flows from the branching passage (42), and a second channel (44) which a path length is shorter than that of the first channel (43). An inlet port, a first outlet port, and a second outlet port, are defined on an inner face of the branching passage (42), and a distance between a center of the inlet port and a center of the first outlet port is smaller than a distance between the center of the inlet port and a center of the second outlet port.