Linear Ultrasonic Motor Triangular Rolling Member Arrangement
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Solution Overview
Problem
In linear ultrasonic motors, the arrangement of rolling members to prevent them from entering between drivers results in a larger unit dimension, compromising output and drive efficiency.
Innovation Solution
A compact driving apparatus design featuring a movable part with a piezoelectric element and pressurization part that applies an impression force, using a rolling part sandwiched between the movable and cover parts, with guide parts forming a triangular arrangement to maintain efficient drive without increasing unit dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rolling members are arranged to prevent them from entering between drivers, then reliability is improved, but the entire dimension of the unit in the drive direction becomes larger
Solution Approach 1:
The patent transitions from a linear arrangement of rolling members in the drive direction to a triangular arrangement in the width direction. The rolling members are positioned at vertices of a triangle with one side parallel to the drive direction, changing the spatial dimension of their configuration. This dimensional shift allows the rolling members to effectively prevent entry between drivers while maintaining a compact length in the drive direction, thus resolving the contradiction between reliability and unit dimension.
2Reliability
If the arrangement span of rolling members is increased to maintain configuration, then reliability is improved, but the unit dimension in drive direction increases
Solution Approach 1:
The patent repositions the rolling members from a linear span along the drive direction to a triangular configuration where the base of the triangle is oriented perpendicular to the drive direction. This dimensional reorientation allows the rolling members to maintain stable spacing and configuration without increasing the arrangement span in the drive direction, thereby preserving reliability while reducing the unit dimension in the critical drive direction.
3Length of moving object
If compact design is achieved, then unit dimension is reduced, but it may compromise output and drive efficiency
Solution Approach 1:
By arranging the rolling members in a triangular configuration with the base perpendicular to the drive direction, the patent achieves a compact design in the drive direction without compromising power transmission. The triangular arrangement provides stable geometric support and efficient force distribution, maintaining drive efficiency while reducing the unit dimension in the drive direction.
Solution Approach 2:
The pressing member is positioned to apply pressing force to the rolling members before operation begins, pre-establishing the optimal triangular configuration. This preliminary positioning ensures that the rolling members are correctly arranged to provide both compact dimensions and efficient power transmission from the outset, avoiding the need for larger dimensions to compensate for misalignment during operation.
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 linear ultrasonic motor that maintains output and drive efficiency without enlarging the unit's drive direction dimension.
Implementation Method 1
a movable part including a vibrator including a piezoelectric element (102)
Implementation Method 2
a rolling part (111a, 111b, 111c) interposed between the movable part and the cover part
Data Source
AI summary
A driving apparatus according to the present invention includes: a movable part including a vibrator including a piezoelectric element and a pressurization part for bringing the vibrator into pressure contact with a base part by applying impression force to the vibrator, the movable part being linearly driven; and a cover part for receiving reactive force of the impression force through intermediation of a rolling part, the cover part being fixed to the base part by a holding part extending in a direction crossing a movement direction of the movable part, in which the rolling part is sandwiched by a guide part of the movable part extending in the movement direction of the movable part and a cover guide part of the cover part extending in the movement direction of the movable part, and the movable part is positioned on an outer side beyond a side of the holding part facing the movable part.