Compact Linear Ultrasonic Motor with Equidistant Guide
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Solution Overview
Problem
Conventional linear drive ultrasonic motors have a thickness issue due to the arrangement of components in the pressurizing direction, which increases the motor's overall thickness.
Innovation Solution
A linear ultrasonic motor design where the guide portion is positioned equidistant from the pressurizing plane, intersecting the moving direction, to reduce thickness without compromising output or drive efficiency, incorporating a vibration element, slider, vibration element supporting member, and pressurizing portion with a guide portion that sandwiches the vibration element's contact position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotational member, rail, vibration body, spring member and fixing plate are arranged in series in the pressurizing direction, then the functions of supporting the vibration node portion and pressurizing the vibration body are achieved, but the thickness of the motor increases
Solution Approach 1:
The patent combines the support function and pressurizing function into a single integrated structure. The vibration body serves dual purposes: it is both supported at its node portion and pressurized against the rail simultaneously. The spring member is positioned to provide both support and pressurizing forces through its elastic deformation, eliminating the need for separate rotational member and pressurizing plate structures.
Solution Approach 2:
The patent repositions components from a series arrangement in the pressurizing direction to a more spatially distributed configuration. The guide portion extends in the moving direction rather than stacking components in the pressurizing direction, allowing the vibration body to be both supported and pressurized without increasing thickness in the pressurizing axis.
2Length of moving object
If the thickness of the motor is reduced by changing the arrangement of components, then the motor becomes more compact, but the output and drive efficiency may be compromised
Solution Approach 1:
The patent applies different functional qualities to different regions of the vibration body. The first region (vibration node portion) is optimized for support with minimal displacement, while the second region (opposite surface) is optimized for pressurizing contact with the rail. This local differentiation allows both support and drive functions to be performed effectively within a compact thickness.
Solution Approach 2:
The vibration body serves multiple functions simultaneously: it is supported at its node portion, pressurized against the rail, and generates ultrasonic vibrations for driving the rail. The spring member also provides both support and pressurizing forces. This multi-functionality eliminates the need for separate dedicated components, maintaining power output while reducing overall motor thickness.
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 design achieves a compact motor with reduced thickness in the pressurizing direction while maintaining drive efficiency and output, suitable for applications like digital camera focus drive mechanisms.
Implementation Method 1
a piezoelectric element for generating periodical vibrations in an ultrasonic range by applying a high frequency voltage is adopted as a vibration element
Implementation Method 2
ultrasonic vibrations of the vibration body frictionally drive the rail
Data Source
AI summary
A small linear ultrasonic motor includes: a vibration element generating ultrasonic vibrations by applying high frequency drive voltage; a slider against which vibration element is pressed and which is relatively moved by the ultrasonic vibrations; a vibration element supporting member retaining the vibration element and relatively moving with respect to the slider; a guide portion guiding a moving direction of the relative movement of the vibration element supporting member; and a pressurizing portion pressing the vibration element against the slider, wherein the guide portion is arranged sandwiching a position at which the vibration element is pressed against the slider, in a plane that includes the moving direction and intersects with a pressurizing direction of a pressurizing force exerted by the pressurizing portion, and at least each part of the pressurizing portion and the guide portion is disposed at a position equidistant from the plane in the pressurizing direction.