Vibration Wave Motor Sliding Guide Friction Reduction

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Solution Overview

Problem

Conventional ultrasonic motors face challenges in downsizing and simplification while maintaining driving force, as the resultant force of the reactive force and biasing force acts as drag on guide shafts and sliding holes, increasing frictional force and decreasing driving force.

Innovation Solution

A vibration wave motor design incorporating a sliding guide mechanism with a vibrator, friction member, moving member, coupling member, press member, and biasing member, where the frictional contact force and biasing contact force directions are parallel and opposite, and the load center of the biasing contact force is within the outer shape of the vibrator, allowing for efficient force transmission without rolling balls, thus reducing frictional force and maintaining driving force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a sliding structure with guide shafts and sliding holes is used to downsize the ultrasonic motor, then the apparatus can be downsized and simplified without rolling balls, but the resultant force of reactive force and biasing force acts as drag on the guide shafts and sliding holes, increasing frictional force and decreasing driving force

Engineering Contradiction:

Improvesize of ultrasonic motorVSAvoiddriving force

Core Design Contradiction:

Volume of moving objectVSForce

Solution Approach 1:

The patent extracts the harmful drag force component by repositioning the biasing force application point. The biasing member is configured to apply force at a location that creates a moment counteracting the drag on the guide shafts, effectively separating the useful biasing function from the harmful frictional effect.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies beforehand cushioning by pre-configuring the biasing member and its attachment geometry to counteract the drag force before it fully manifests. The moment arm created by the biasing force arrangement compensates for the frictional drag on the guide shafts in advance, maintaining driving force despite the presence of the sliding guide structure.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Device complexity

If rolling balls are omitted to simplify the structure, then the apparatus can be downsized and simplified, but the sliding structure increases frictional force due to drag on guide shafts and sliding holes

Engineering Contradiction:

Improvestructure complexityVSAvoidfrictional force

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful drag force on the guide shafts into a beneficial arrangement by positioning the biasing member to create a counteracting moment. The same structural elements that cause drag are worked with rather than against, using the biasing force geometry to compensate for the frictional effects and maintain efficient force transmission.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies the counterweight principle by configuring the biasing member to create a moment that counteracts the drag force on the guide shafts. The attachment point and orientation of the biasing member are specifically designed to generate a counterbalancing effect that offsets the harmful frictional forces in the sliding guide structure.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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

The proposed solution enables the downsizing and simplification of the vibration wave motor without reducing driving force, as the sliding guide reduces frictional resistance, allowing for compact and efficient linear motion without the need for rolling balls, thus achieving high position accuracy and reduced motor vibration.

Implementation Method 1

a piezoelectric element configured to generate a vibration

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a high-frequency voltage is applied to a piezoelectric element to ultrasonically vibrate a vibrator

Methodology Applied

Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 3

The ultrasonic vibration of the vibrator generates a driving force between a friction member and the vibrator pressed against the friction member

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10425020B2Vibration wave motor, linear driving apparatus using vibration wave motor, and optical apparatus

Publication Date: 2019.09.24 CANON KK

AI summary

In a linear driving apparatus including a vibration wave motor, a sliding guide method is used as a guiding method for a moving member. The apparatus further includes a driving target body movable in a moving direction, a transmission member configured to engage with the driving target body, abut against the abutment part of the moving member, and transmit the driving force of the vibration wave motor to the driving target body, and a biasing member configured to apply a biasing force between the transmission member and the abutment part. The direction of a frictional contact force that the vibrator receives from the friction member and the direction of a biasing contact force that the abutment part receives from the biasing member are parallel and opposite, and the load center of the distribution load of the biasing contact force exists in the range of the outside shape of the vibrator.