Vibration-Type Actuator Pressurizing Unit for Miniaturization
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Solution Overview
Problem
Existing vibration-type actuators face challenges in miniaturization and stabilization of the pressure state between the driven body and the vibration body, particularly due to the need for thick magnets and unstable pressure forces when the projections are small.
Innovation Solution
A vibration-type actuator design incorporating a vibration body with projections, an electro-mechanical energy conversion element, and a pressurizing unit that includes an energizing member, support member, and transfer member, where the contact area between the projection and the driven body is shorter than the areas where pressure force is transferred, ensuring stable pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a magnet is used to press the driven body against the projections, then pressure force is generated, but the actuator size increases due to the need for a thick magnet
Solution Approach 1:
The patent replaces the magnetic pressurizing system with a mechanical pressurizing unit consisting of a pressurizing member that directly applies pressure force to the driven body through the projections. This mechanical substitution eliminates the need for thick magnets while maintaining sufficient pressure force for reliable operation.
Solution Approach 2:
The patent extracts the magnet from the actuator structure entirely, removing the source of the volume problem. The pressurizing function is achieved through a separate mechanical pressurizing unit that can be integrated into the actuator structure without requiring large magnetic components.
2Volume of moving object
If the projections are made small to reduce size, then miniaturization is achieved, but the pressure force becomes unstable and insufficient driving force occurs
Solution Approach 1:
The patent applies different local qualities to different parts of the system: the projections remain small for miniaturization, while the pressurizing member is designed with specific mechanical properties (elasticity, compliance) to provide stable pressure force. The pressurizing member can deform locally to maintain optimal contact pressure even with small projections.
Solution Approach 2:
The pressurizing member is designed to be compliant and dynamic, allowing it to adapt its pressure application to the actual contact conditions with the small projections. This dynamic adjustment capability ensures stable pressure force despite the reduced size of the projections.
3Reliability
If the contact area between projection and driven body is increased to stabilize pressure, then pressure stability improves, but the actuator cannot be miniaturized
Solution Approach 1:
The patent resolves the area conflict by operating in different dimensional spaces: the contact area in the X-Y plane remains small for miniaturization, while the pressurizing member extends in the Z-direction (thickness direction) to provide sufficient pressure force. The pressurizing member's length in the pressurizing direction compensates for the small contact area.
4Force
If a magnet is used for pressurizing, then pressure force is generated, but the number of components and structural complexity increases
Solution Approach 1:
The patent merges the pressurizing function into the actuator structure itself through the pressurizing member, which can be integrated with the vibration body or driven body. This consolidation eliminates the need for separate magnetic pressurizing components, reducing overall device complexity while maintaining the pressure force function.
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
This design achieves miniaturization and stabilizes the pressure state between the driven body and the vibration body, resulting in improved drive performance and reduced component count.
Implementation Method 1
a piezoelectric device 113 that is an electro-mechanical energy conversion element attached to the other side of the vibration body 111
Implementation Method 2
friction drive force is given to the driven body in the X-direction, and the vibration body 111 and the driven body move relatively
Data Source
AI summary
A vibration-type actuator can be miniaturized and can stabilize a pressure state between a driven body and a vibration body. A pressurizing unit applies a pressure force between projections on the vibration body and the driven body. A piezoelectric device connected to the vibration body on a surface opposite to the projections moves the driven body by vibration occurring in the vibration body when a drive voltage is applied. The pressurizing unit includes an energizing member, its support member, and a transfer member. A length of a contact area between the projections and the driven body is shorter than a length of an area in which the transfer member transfers the pressure force from the energizing member to the vibration body and a length of a contact area between the energizing member and the support member, in a direction perpendicular to the moving direction and to a pressurizing direction by the pressurizing unit.