Work Tool Vibration Damping via Segmented Housing and Elastic Members

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Solution Overview

Problem

The existing hand-held work tools experience increased vibration due to the close arrangement of heavy components, leading to reduced moment of inertia and inefficient operation.

Innovation Solution

The work tool design incorporates a brushless motor, a spindle, and elastic members to distribute the weight and reduce vibration, with the motor and spindle arranged in a parallel configuration and elastic members connecting the inner and outer housings to prevent vibration transmission to the user-held handle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the spindle and motor are arranged in parallel close to each other, then the work tool size is reduced, but the moment of inertia of the housing is reduced and vibration is increased

Engineering Contradiction:

Improvework tool sizeVSAvoidvibration

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The housing is divided into an outer housing and an inner housing that are separable and can move relative to each other. The inner housing contains the motor and spindle, while the outer housing contains the handle. This segmentation allows the heavy components to be isolated from the user-held portion, reducing vibration transmission while maintaining compact overall dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An elastic member is introduced as an intermediary element between the inner housing and the outer housing. This elastic member connects the two housings while allowing relative movement, serving as a vibration isolation mechanism that prevents direct transmission of vibrations from the motor-spindle assembly to the handle.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If heavy parts are arranged close to each other, then the device structure is compact, but the moment of inertia is reduced leading to increased vibration

Engineering Contradiction:

Improvestructure compactnessVSAvoidvibration

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The housing structure is segmented into outer and inner housings with distinct functional zones. The inner housing accommodates heavy components (motor and spindle) while the outer housing contains the handle, creating spatial separation that increases moment of inertia without significantly increasing overall device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic member acts as a mediator that connects the inner and outer housings while providing vibration isolation. This allows the heavy parts to be positioned close to each other for structural compactness while the elastic member prevents vibration transmission, effectively decoupling the two concerns.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If the inner housing and outer housing are integrally formed, then the manufacturing is simplified, but vibration is transmitted directly to the user-held handle

Engineering Contradiction:

Improvehousing manufacturingVSAvoidvibration transmission

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The housing is manufactured as separate components (outer housing and inner housing) rather than as a single integral piece. This segmentation enables vibration isolation while the components can still be efficiently manufactured using standard molding or machining processes, and assembled through straightforward connection methods.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The elastic member is positioned between the inner and outer housings to serve as a vibration-isolating intermediary. This configuration allows each housing to be manufactured separately with optimized structures, then assembled with the elastic member providing the necessary decoupling to prevent vibration transmission to the handle.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively reduces vibration, enhancing user comfort and tool stability during operations like cutting, scraping, and grinding by distributing weight and increasing the moment of inertia, thereby improving operational efficiency.

Implementation Method 1

an elastic member configured to elastically connect the inner housing and outer housing

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

prevent vibration caused in the inner housing from being transmitted to the outer housing

Methodology Applied

Scientific EffectVibration: Vibration

Data Source

PatentUS11478917B2Work tool with vibration dampers

Publication Date: 2022.10.25 MAKITA CORP

AI summary

It is an object of the invention to provide a more rational vibration reducing technique for a work tool. A representative work tool 100 has an outer housing 102, an inner housing 104, a brushless motor 115, a spindle 124 having a rotation axis extending in parallel to a rotation output shaft of the brushless motor 115 and configured to be rotated on the rotation axis within a prescribed angular range to drive a tool accessory 145, a front elastic member 110a disposed between a front inner housing region 104a and a front outer housing region 102a, and a rear elastic member 110c disposed between at least one of an intermediate inner housing region 104b and a rear inner housing region 104c and at least one of an intermediate outer housing region 102b and a rear outer housing region 102c.