Ultrasonic Motor Spring-Shaft Geometry to Prevent Misalignment
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Solution Overview
Problem
Conventional ultrasonic motors experience misalignment between the spring member and shaft member due to stress and heat accumulation during long-term use, leading to abnormal noise and potential mechanical failure.
Innovation Solution
An ultrasonic motor design featuring a stator with a piezoelectric device, a rotor in contact with the stator, a plate-shaped spring member providing elastic force, and a shaft member with a noncircular opening shape, where the spring member's convex portion mates with the shaft member's mating portion, reducing the likelihood of misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the rotating shaft, rotor, collar, and disc spring are complexly combined together, then the structure can provide stable support and positioning, but loosening may be caused at contact portions during long-term use due to stress and heat, leading to misalignment
Solution Approach 1:
The opening of the spring member is designed with a noncircular shape that corresponds to the mating portion on the shaft member. This asymmetric geometric configuration creates a unique fit that prevents rotational misalignment and loosening during operation, directly resolving the contradiction between structural stability and alignment reliability.
2Manufacturing precision
If convex portions and concave portions are used to mate the collar and disc spring, then positioning can be achieved, but abnormal noise may be caused due to contact between members when misalignment occurs
Solution Approach 1:
The noncircular opening shape with convex portions creates an asymmetric mating relationship with corresponding concave portions on the shaft member. This asymmetric design ensures precise positioning while maintaining continuous contact without misalignment, thereby preventing the abnormal noise that would result from loose contacts.
3Device complexity
If multiple members are closely combined to achieve compact structure, then space utilization is improved, but misalignment between spring member and shaft member occurs under continuous stress and heat
Solution Approach 1:
The asymmetric noncircular opening shape integrated into the spring member creates a geometry-dependent fit with the shaft member's mating portion. This design maintains compact structure while the asymmetric geometry inherently prevents misalignment under stress and heat, resolving the contradiction between compactness and alignment stability.
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 effectively minimizes misalignment between the spring and shaft members, ensuring stable operation and reducing the occurrence of abnormal noise and mechanical loosening over extended periods.
Implementation Method 1
a stator including a vibrating body in a plate shape having a first principal surface and a second principal surface opposed to each other, and including a piezoelectric device provided on the first principal surface of the vibrating body
Implementation Method 2
a spring member in a plate shape having an opening and configured to give elastic force to the rotor in a direction from a side of the rotor to a side of the stator
Data Source
AI summary
A device may include a stator including a vibrating body in a plate shape having a first principal surface and a second principal surface opposed to each other, and including a piezoelectric device provided on the first principal surface of the vibrating body. A device may include a rotor directly or indirectly in contact with the second principal surface of the vibrating body. A device may include a spring in a plate shape having an opening and configured to give elastic force to the rotor in a direction from a side of the rotor to a side of the stator. A device may include a shaft inserted into the opening of the spring and having a mating portion, wherein. A device may include a shape of the opening of the spring is a noncircular shape in a plan view.