Linear Actuator Vibration Offset via Opposing Magnetic Blocks
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Solution Overview
Problem
Existing linear actuators used in oral cavity hygiene devices, such as electric toothbrushes, face challenges in compactness and vibration reduction, as they often require larger sizes and separate components to manage reciprocating elements and vibrations effectively.
Innovation Solution
A compact linear actuator design featuring two magnetic blocks arranged in parallel, reciprocating in opposite phases, with an output shaft connected to one block and a weight connected to the other, utilizing an elastic coupling and plate spring units to reduce size and vibration, eliminating the need for additional bearings and enhancing driving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a single movable element is used in the linear actuator, then the structure is simple, but vibration reduction is insufficient
Solution Approach 1:
The patent combines two movable elements (first and second magnetic blocks) into a single actuator structure, where both elements reciprocate simultaneously to generate opposing vibrations that cancel each other out. This merging approach reduces overall vibration while maintaining structural integration, rather than using separate vibration reduction components.
Solution Approach 2:
The patent implements a counterweight mechanism where the second magnetic block acts as a counterbalance to the first magnetic block. By configuring the second block to reciprocate in opposition to the first block, the system creates counteracting forces that offset harmful vibrations generated during operation.
2Object-generated harmful factors
If multiple movable elements are arranged coaxially with the output shaft, then vibration can be reduced, but the actuator size increases in the axial direction
Solution Approach 1:
The patent transitions from axial arrangement to radial arrangement of the magnetic blocks. Instead of stacking movable elements along the axial direction of the output shaft, the first and second magnetic blocks are positioned side-by-side in the radial direction, perpendicular to the output shaft axis. This dimensional change reduces axial length while maintaining vibration reduction capabilities through opposing reciprocation.
3Object-generated harmful factors
If separate components are used for vibration reduction, then vibration can be offset, but the device complexity and size increase
Solution Approach 1:
The patent integrates the vibration reduction function directly into the movable elements themselves, rather than adding separate vibration reduction components. The first and second magnetic blocks serve dual purposes: they generate the reciprocating motion needed for actuation while simultaneously providing counterbalancing forces to reduce vibration. This merging of functions eliminates additional parts and simplifies the overall structure.
Solution Approach 2:
The magnetic blocks are designed to perform multiple functions simultaneously: they act as the movable elements that generate reciprocating motion for actuation, and they also serve as counterweights for vibration reduction. This multi-functionality eliminates the need for separate dedicated vibration reduction components, reducing device complexity while achieving effective vibration control.
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 reduction in size and power consumption while effectively offsetting vibration, simplifying manufacturing and reducing the load on components, thereby improving the driving efficiency and reducing the overall size of the linear actuator.
Implementation Method 1
The electromagnetic block (10) includes a core (11) and a winding (12). When current is supplied to the winding (12), the electromagnetic block functions as an electromagnet that generates a magnetic field to attract and repel the magnetic blocks
Implementation Method 2
the magnetic blocks (20a and 20b) are reciprocated by a magnetic thrust generated between the permanent magnet (21) and the core (11), which functions as a magnetic pole of the electromagnet
Implementation Method 3
the magnetic blocks (20a and 20b) are reciprocated by a magnetic thrust generated between the permanent magnet (21) and the core (11)
Implementation Method 4
the output shaft (30) and the weight (60) are arranged on opposite ends. Thus, it is relatively easy to align the center of gravity positions of the magnetic blocks (20a and 20b) in the direction orthogonal to the reciprocation direction. This allows for reduction in vibration
Implementation Method 5
utilizing an elastic coupling and plate spring units to reduce size and vibration
Data Source
Figure 1~2
Figure 3(a)~3(c)
Figure 4
AI summary
A linear actuator (1) comprises an electromagnetic block (10) which functions as an electromagnet, a plurality of magnetic blocks (20a, 20b) including a permanent magnet, and an output axle (30) which is disposed upon one of the plurality of magnetic blocks (20a, 20b). The plurality of magnetic blocks (20a, 20b) are disposed in parallel, and move reciprocally in an inverse phase when current is applied to the electromagnetic block (10) The output axle (30) has an axial direction of the reciprocal movement direction of the magnetic block.