Electric Blower Bearing Layout for High-Speed Alignment and Cooling

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Solution Overview

Problem

Existing electric blowers face challenges in maintaining accurate center alignment of the rotation shaft, stator, and bearings at high speeds, leading to whirling, and require enhanced heat dissipation as motor rotation speed increases.

Innovation Solution

The electric blower design features a rotation shaft supported by bearings disposed between the moving blade and stator, with a second air path for heat dissipation within the frame, ensuring accurate center alignment and efficient heat dissipation through airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the rotation speed of the motor is increased to achieve downsizing, then the motor size is reduced, but whirling is caused by centrifugal force due to misalignment of centers

Engineering Contradiction:
Improvemotor sizeVSAvoidcenter alignment stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent merges the bearing support function into the stator structure itself, making the stator serve dual purposes: electromagnetic function and bearing support. This integration ensures that the centers of the rotation shaft, stator, and bearings are accurately matched, preventing whirling even at high rotation speeds achieved through downsizing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a bearing support portion as an intermediary structure within the stator that specifically addresses the center alignment issue. This intermediary component provides precise positioning for the bearings, ensuring accurate center matching between the rotation shaft, stator, and bearings, thereby eliminating whirling caused by centrifugal force during high-speed rotation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the rotation speed of the motor is increased, then the motor power is improved, but heat generation increases requiring enhanced heat dissipation

Engineering Contradiction:
Improvemotor powerVSAvoidheat generation
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent makes the stator multi-functional by integrating both electromagnetic function and heat dissipation function. The stator not only generates electromagnetic force but also serves as a heat sink with built-in heat dissipation fins, allowing it to dissipate the increased heat generated by high-speed rotation effectively.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The stator structure serves itself by incorporating heat dissipation fins directly into its body. The same stator that generates electromagnetic force also provides its own cooling through the heat dissipation fins, eliminating the need for separate cooling systems and efficiently managing the heat generated by high-power operation.

Inventive Principle:
Principle #25Self-service

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 prevents whirling due to centrifugal force and enhances heat dissipation efficiency, maintaining stability and performance at higher rotation speeds.

Implementation Method 1

the rotation shaft is rotatably supported by a bearing portion

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

heat generated by the motor is efficiently dissipated by air flowing through the second air path provided inside the frame

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

heat generated by the motor is efficiently dissipated by air flowing through the second air path

Methodology Applied
Scientific EffectHeat dissipation: Heat Sink

Implementation Method 4

a centrifugal force acting on a rotating portion of the motor increases. Thus, if a center of a rotation shaft of the motor, a center of a stator, and centers of bearings supporting the rotation shaft are not accurately matched with each other, whirling may be caused by the centrifugal force

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3760878B1Electric blower, electric vacuum cleaner and hand dryer
Publication Date: 2023.05.10 MITSUBISHI ELECTRIC CORP
  • EP3760878B1 patent drawingFigure 1~2
  • EP3760878B1 patent drawingFigure 3~4
  • EP3760878B1 patent drawingFigure 5(A)~5(C)

AI summary

An electric blower includes a motor including a rotor having a rotation shaft, and a stator provided to surround the rotor, a moving blade mounted at one end side of the rotation shaft in the axial direction of the rotation shaft, a bearing portion provided between the moving blade and the stator in the axial direction and rotatably supporting the rotation shaft, and a frame. The frame includes a motor housing portion housing the stator, a bearing housing portion housing the bearing portion, a wall formed between the motor housing portion and the bearing housing portion and facing the moving blade, and a hole passing through the wall. The electric blower further includes a first air path outside the frame, and a second air path inside the frame. An air volume in the first air path is larger than an air volume in the second air path.