Piezoelectric Gripping Device Torque Amplification
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Solution Overview
Problem
Existing gripping devices, such as those described in JP-A-2001-341091, often have insufficient gripping force due to unclear ultrasonic motor configurations and may not effectively utilize the rotational torque for stable object handling.
Innovation Solution
A gripping device incorporating a piezoelectric motor with a vibrating portion and a convex portion that transmits vibration to a rotating member, where the contact point is located outside the pinion's outer circumference, allowing for increased rotational torque and enhanced gripping force through the use of racks meshing with the pinion, which are coupled to gripping parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the contact portion is located inside or on the outer circumference of the pinion, then the structure is compact and simple, but the rotational torque is limited and gripping force is insufficient
Solution Approach 1:
The contact portion is positioned in the radial direction outside the pinion's outer circumference, utilizing the radial dimension to increase the moment arm for torque generation. This dimensional relocation allows the convex portion to apply force at a greater distance from the rotation axis, thereby amplifying rotational torque and gripping force without adding complex mechanical structures.
Solution Approach 2:
The convex portion acts as an intermediary element between the vibrating portion and the rotating member. By positioning this contact portion outside the pinion, it serves as a force amplification mediator that converts the vibration force into enhanced rotational torque, resolving the contradiction between structural simplicity and force generation capability.
2Force
If a traditional ultrasonic motor configuration is used, then the structure is well-established and easy to manufacture, but the gripping force may be insufficient
Solution Approach 1:
The invention modifies only the local contact portion configuration of the ultrasonic motor, positioning the convex portion outside the pinion's outer circumference. This localized modification preserves the overall ease of manufacturing traditional ultrasonic motors while significantly improving the gripping force through the enhanced torque generation at the modified contact point.
3Ease of operation
If additional braking mechanisms are added to control rotation, then the control precision is improved, but the device complexity increases
Solution Approach 1:
The vibrating portion inherently provides both driving and braking functions through its oscillatory motion. When the vibration stops or reverses direction, the friction between the convex portion and rotating member naturally provides braking effect, eliminating the need for separate braking mechanisms while maintaining rotation control capability.
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 solution provides a gripping device capable of exerting a larger gripping force, enabling stable object handling and grip adjustment, with the ability to rotate the rotating member with increased torque without additional braking mechanisms, thus improving the reliability of object manipulation.
Implementation Method 1
a piezoelectric drive unit (6) having a vibrating portion (611) in which a piezoelectric material (6113) vibrates
Implementation Method 2
a convex portion (614) provided in the vibrating portion (611), being in contact with the driven member (55) and transmitting the vibration of the vibrating portion (611) to the driven member (55)
Implementation Method 3
a rack (31, 32) meshing with the pinion (51) and moving with rotation of the pinion (51)
Data Source
AI summary
A gripping device includes a rotating member having a pinion and rotating about a center axis of the pinion, a drive piezoelectric unit having a vibrating portion that vibrates with expansion and contraction of a piezoelectric material, and a convex portion provided in the vibrating portion, being in contact with the rotating member, and transmitting vibration of the vibrating portion to the rotating member, a rack meshing with the pinion and moving with rotation of the pinion, and a gripping part coupled to the rack, wherein a contact portion in which the convex portion and the rotating member are in contact is located outside of an outer circumference of the pinion in a plan view from a direction of a rotation axis of the rotating member.