Linear Actuator Buffer Member Elastic Deformation

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Solution Overview

Problem

Existing linear actuators face reliability issues due to potential contact between the stator and movable element, requiring precise manufacturing and assembly, which complicates component management and reduces yield, especially when trying to minimize the gap between these components for improved performance.

Innovation Solution

A linear actuator structure with an elastically deformable output shaft and connecting member, coupled with a buffer member that contacts the output shaft before the stator and movable element can, maintaining a larger gap between the output shaft and buffer member, thus preventing direct contact between the stator and movable element, and incorporating a contact sensor to detect and manage this interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the interval of the stator and the movable element is reduced to improve performance, then the performance of the linear actuator is improved, but high accuracy is needed for molding and assembling components, which results in difficult manufacturing and component management and lowers yield

Engineering Contradiction:
ImproveperformanceVSAvoidmanufacturing accuracy
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent introduces a buffer member as an intermediary component between the stator and the movable element. This buffer member absorbs external forces and prevents direct contact between the stator and movable element, allowing the use of larger intervals without compromising performance. This mediator approach resolves the contradiction by enabling larger gaps (easier manufacturing) while maintaining actuator performance through the buffer's protective function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the interval of the stator and the buffer member is made smaller than the interval of the stator and the movable element to prevent contact, then contact protection is improved, but high accuracy is needed for molding and assembling components, which results in difficult manufacturing and component management and lowers yield

Engineering Contradiction:
Improvecontact protectionVSAvoidassembly accuracy
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent inverts the traditional protective mechanism by making the output shaft and connecting member elastically deformable instead of making the buffer member interval smaller. The elastic deformation of the output shaft and connecting member allows the buffer member to contact first under external forces, providing protection without requiring precise small intervals. This inversion resolves the contradiction by achieving contact protection through material properties rather than dimensional precision.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If the output shaft and connecting member are made elastically deformable to allow buffer contact first, then the load on supporting components is reduced and manufacturing is simplified, but the structural complexity increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent changes the physical parameter of the output shaft and connecting member by making them elastically deformable. This parameter change allows the system to absorb external forces through elastic deformation rather than requiring complex mechanical protection mechanisms. The elastic deformation capability simplifies the overall structure while maintaining protection functions, resolving the contradiction between manufacturing simplicity and structural complexity.

Inventive Principle:
Principle #35Parameter changes

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 effectively prevents contact between the stator and movable element, simplifies manufacturing, and reduces the load on supporting components by allowing the output shaft and buffer member to contact first under external forces, enhancing the reliability and ease of production of linear actuators, particularly in oral cavity hygiene devices like electric toothbrushes.

Implementation Method 1

At least one of the output shaft and the connecting member is formed to be elastically deformable

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2790310B1Linear actuator structural body and oral cavity hygiene device provided with same
Publication Date: 2021.01.06 PANASONIC HOLDINGS CORP
  • EP2790310B1 patent drawingFigure 1~2
  • EP2790310B1 patent drawingFigure 3~5
  • EP2790310B1 patent drawingFigure 6~7

AI summary

This linear actuator structural body (2) is provided with: a casing (60), and a linear actuator (1) which is at least partially disposed in the casing (60). The linear actuator (1) is provided with: a stator (10); a mover (20) disposed so that a first spacing (d1) is present with respect to the stator; and an output shaft (30) linked via a connection member (31) to the mover (20). The output shaft (30) and/or the connection member (31) is formed so as to be capable of elastic deformation. The casing has a buffering member (64) provided so as to be capable of being brought into contact with the output shaft (30) and so that a second spacing (d2) is present with respect to the output shaft (30). The second spacing (d2) is greater than or equal to the first spacing (d1).