Refrigerant Passage Slit Structure for Rotary Machine Noise Control

Solution Overview

Problem

In rotary electrical machines, the intermittent magnetic force between the rotor and tooth portions causes stator vibration, which is transmitted to the outer peripheral wall, leading to noise and potential refrigerant flow issues due to the absence of a partition wall.

Innovation Solution

A rotary electrical machine design featuring a refrigerant flow passage with an inner and outer peripheral wall, an inlet and outlet positioned differently in the circumferential direction, and a second flow passage with a slit in the partition wall to reduce vibration transmission while maintaining refrigerant flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a partition wall portion is provided to suppress vibration transmission, then noise is reduced, but the refrigerant flow passage is blocked and cooling function deteriorates

Engineering Contradiction:

ImprovenoiseVSAvoidcooling function

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The partition wall portion is designed with a slit that has different properties from the main refrigerant flow passage. The slit width is specifically controlled to be smaller than the width of the first flow passage, creating local quality differences that allow vibration isolation while maintaining refrigerant flow through the main passage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The partition wall portion is segmented by introducing a slit, which divides it into multiple parts. This segmentation allows the partition wall to isolate vibrations while still permitting refrigerant to pass through the main flow passage, resolving the contradiction between noise reduction and cooling function.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the partition wall portion is removed to maintain refrigerant flow, then cooling function is maintained, but vibration transmits freely and noise increases

Engineering Contradiction:

Improvecooling functionVSAvoidnoise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The partition wall portion is designed with a slit that has different properties from the main refrigerant flow passage. The slit width is specifically controlled to be smaller than the width of the first flow passage, creating local quality differences that allow vibration isolation while maintaining refrigerant flow through the main passage.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The partition wall portion is segmented by introducing a slit, which divides it into multiple parts. This segmentation allows the partition wall to isolate vibrations while still permitting refrigerant to pass through the main flow passage, resolving the contradiction between noise reduction and cooling function.

Inventive Principle:

Principle #1Segmentation

3Reliability

If the slit width is increased to improve refrigerant flow, then cooling function is enhanced, but vibration isolation effectiveness is reduced

Engineering Contradiction:

Improvecooling functionVSAvoidnoise

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The slit width is carefully controlled to be smaller than the width of the first flow passage. This parameter change creates a flow resistance difference that directs refrigerant through the main passage while maintaining vibration isolation effectiveness, resolving the contradiction between cooling function and noise reduction.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The partition wall portion is designed with a slit that has different properties from the main refrigerant flow passage. The slit width is specifically controlled to be smaller than the width of the first flow passage, creating local quality differences that allow vibration isolation while maintaining refrigerant flow through the main passage.

Inventive Principle:

Principle #3Local quality

4Object-affected harmful factors

If the slit width is decreased to improve vibration isolation, then noise is reduced, but refrigerant flow through the second passage is restricted

Engineering Contradiction:

ImprovenoiseVSAvoidrefrigerant flow

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The slit width is carefully controlled to be smaller than the width of the first flow passage. This parameter change creates a flow resistance difference that directs refrigerant through the main passage while maintaining vibration isolation effectiveness, resolving the contradiction between cooling function and noise reduction.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The partition wall portion is segmented by introducing a slit, which divides it into multiple parts. This segmentation allows the partition wall to isolate vibrations while still permitting refrigerant to pass through the main flow passage, resolving the contradiction between noise reduction and cooling function.

Inventive Principle:

Principle #1Segmentation

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 design effectively suppresses the transmission of stator vibration to the outer peripheral wall, reducing noise while ensuring that the refrigerant flow is not significantly compromised, thus maintaining an effective cooling function.

Implementation Method 1

a refrigerant flow passage through which a refrigerant for cooling the stator and the like flows

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

to generate a rotating magnetic field in a case where current flows through coils wound around the tooth portions and to rotate the rotor via a magnetic force generated by the rotating magnetic field

Methodology Applied

Scientific EffectMagnetic force: Lorentz Force

Implementation Method 3

A slit penetrating the partition wall portion in the circumferential direction is formed in the partition wall portion... suppress the transmission of vibration from the inner peripheral wall to the outer peripheral wall

Methodology Applied

Scientific EffectVibration isolation: Damping

Data Source

PatentUS12334795B2Rotary electrical machine refrigerant flow passage partition wall gap

Publication Date: 2025.06.17 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD

AI summary

A rotary electrical machine includes a housing which includes a flow passage portion in which a refrigerant flow passage through which a refrigerant flows is formed and which houses a rotor and a stator. The refrigerant flow passage includes a first flow passage of which a length from the inlet to the outlet in the circumferential direction is a predetermined length, and a second flow passage of which a length from the inlet to the outlet in the circumferential direction is shorter than that of the first flow passage. The second flow passage is provided with a partition wall portion between the inner peripheral wall and the outer peripheral wall in the radial direction. A slit penetrating the partition wall portion in the circumferential direction is formed in the partition wall portion. A width of the slit is smaller than a width of the first flow passage.