Vibration Wave Actuator Integrated Encoder Inversion

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Solution Overview

Problem

Conventional vibration wave actuators face challenges in reducing size while maintaining high-accuracy positioning and drive performance due to the need for external encoder units and complex vibration design considerations, which can lead to increased size and potential load issues from extended electrical components.

Innovation Solution

The vibration wave actuator incorporates a vibration member with elastic projections and an integrated detection unit, where the encoder is positioned between the vibration member and contact member, allowing for reduced size without compromising drive performance by using a reflective optical sensor and strategically placing the scale and encoder to minimize space requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the encoder main body is disposed on the contact member side, then the detection unit can be built in, but an electrically conductive member must be extended causing load and bending

Engineering Contradiction:

Improvedetection unit integrationVSAvoidelectrically conductive member strength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The invention inverts the conventional arrangement by placing the detection unit on the vibration member side rather than the contact member side. This inversion eliminates the need to extend electrically conductive members across the contact interface, thereby avoiding the bending loads and strength issues that would result from such extensions.

Inventive Principle:

Principle #13The other way round (Inversion)

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 enables further size reduction of the vibration wave actuator while maintaining high-accuracy positioning and drive performance, as the detection unit is vibration-insulated and efficiently integrated within the actuator's structure, preventing adverse effects on drive performance.

Implementation Method 1

a vibration member (11) including an elastic member (11a) and an electro-mechanical energy transducer (11b)

Methodology Applied

Scientific EffectElectro-mechanical energy transduction: Piezoelectric Effect

Implementation Method 2

an actuator for extracting a driving force through a frictional force by using a small vibration of a vibration member as a driving source

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 3

an optical encoder main body (detection unit)

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS10978966B2Vibration wave actuator, imaging apparatus, and stage apparatus using the same

Publication Date: 2021.04.13 CANON KK

AI summary

A vibration wave actuator has a vibration member including an elastic member and an electro-mechanical energy transducer, and a contact member in contact with the vibration member, and the contact member and the vibration member move relative to each other. The vibration wave actuator includes a detected portion configured to move, together with the contact member, relative to the vibration member, and a detection unit configured to move, together with the vibration member, relative to the contact member to detect displacement information or position information for the detected portion. The vibration member has two projections provided side by side in a direction intersecting with the direction of the relative movement. The contact member contacts the two projections. The detection unit and the detected portion are located between the contact member and the vibration member when viewed from the direction of the relative movement.