Ultrasonic Motor Rolling Support for Position Stability

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Solution Overview

Problem

In ultrasonic motors used in optical devices, the relative positions of the fixing plate and vibrating plate deviate due to impact forces, leading to inaccurate control of the sliding member's position, causing rattle and affecting feeding accuracy.

Innovation Solution

The motor incorporates rolling members that freely move relative to the vibrator support member in the pressurizing direction, coupled with an urging member that applies a force perpendicular to the pressurizing direction, ensuring the base and vibrator are held without rattle, thereby improving the accuracy of the vibrator support member's feeding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring members and rubber sheets are used to support and pressurize the vibrating body, then the vibrating body can be held with pressurizing function, but impact forces cause relative position deviation between fixing plate and vibrating body, leading to rattle and poor feeding accuracy

Engineering Contradiction:
Improveposition control accuracyVSAvoidrelative position stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The support structure is segmented into multiple independent rolling members (at least two) that can move freely in the pressurizing direction. This segmentation allows each rolling member to independently absorb impact forces while maintaining overall pressurizing function, preventing relative position deviation between the fixing plate and vibrating body.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The state of the support members is changed from elastic deformation (spring/rubber) to rolling motion. The rolling members can freely move in the pressurizing direction while maintaining contact, transforming the mechanism from flexible support to controlled rolling contact that prevents rattling while absorbing impacts.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If rigid coupling is used between base and vibrator support member, then position accuracy is improved, but impact forces cause rattle and position deviation

Engineering Contradiction:
Improvefeeding accuracyVSAvoidrattle and position deviation
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The coupling between base and vibrator support member is made dynamic through rolling members that can freely move in the pressurizing direction. This dynamic coupling allows the system to adapt to impact forces while maintaining precise positioning, eliminating rattle without sacrificing feeding accuracy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Rolling members are introduced as intermediary elements between the base and vibrator support member. These intermediaries enable relative movement in the pressurizing direction while maintaining stable coupling in the moving direction, preventing rattle and position deviation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If flexible support is used to absorb impact, then position stability is improved, but feeding accuracy deteriorates due to rattle

Engineering Contradiction:
Improveposition stabilityVSAvoidfeeding accuracy
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The flexible support function is segmented into multiple rolling members that can independently move in the pressurizing direction. This segmentation provides flexibility to absorb impact forces while maintaining stable positioning, preventing rattle and preserving feeding accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support mechanism changes from elastic flexibility (spring/rubber) to rolling flexibility. The rolling members can freely move in the pressurizing direction while maintaining stable contact, providing impact absorption without rattle, thus maintaining both position stability and feeding accuracy.

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 configuration stabilizes the motor components, preventing rattle and maintaining precision in the moving direction, enhancing the feeding accuracy and drive control of the ultrasonic motor, especially in optical devices.

Implementation Method 1

a piezoelectric element 103 is secured to a vibrating plate 101; the piezoelectric element 103 transforms electrical energy to mechanical energy, so that the vibrating plate 101 vibrates

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an elastic member 109 is interposed between the pressurizing plate 108 and the vibrator 100; the elastic member 109 is deformed elastically, so that the vibrator 100 is pressurized against the sliding member 104, thereby generating a friction force

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the vibrating plate 101 and the sliding member 104 are relatively moved by the vibration; the friction force between the vibrating plate and sliding member drives the sliding member

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2889997B1Ultrasonic motor
Publication Date: 2018.11.14 CANON KK
  • EP2889997B1 patent drawingFigure 1
  • EP2889997B1 patent drawingFigure 2
  • EP2889997B1 patent drawingFigure 3

AI summary

An ultrasonic motor is proposed comprising a vibrator (101, 103) that vibrates by a high frequency drive voltage applied thereto, a sliding member (104) driven by frictional contact with the vibrator, pressurizing means (108, 109, 110) for pressurizing the vibrator to the sliding member, a base (102) to which the vibrator is fixed, a vibrator support member (105) holding the base, and coupling means for coupling the vibrator with the vibrator support member. The coupling means includes the base (102), a rolling member (106) that freely moves the base to the vibrator support member in a pressurizing direction (A) of the pressurizing means, and an urging member (107) that urges the rolling member in a direction (B) perpendicular to the pressurizing direction of the pressurizing means.