Oscillatory System Spring Arrangement Compact Drive
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Solution Overview
Problem
Existing oscillatory systems for motorized drive units, such as those in electric toothbrushes, require significant longitudinal space and are not optimal for generating additional oscillatory motions with a restoring force, especially when using rotational springs.
Innovation Solution
An oscillatory system comprising two elongate spring elements with fastening points connected to oscillatory components, allowing for relative rotary movement due to their elasticity, which eliminates the need for additional journaling elements like ball bearings, enabling a compact and cost-effective structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotational springs with base members and disc members are used to generate rotary oscillatory movement, then the oscillatory function is achieved, but the longitudinal space required increases significantly
Solution Approach 1:
The oscillatory system is divided into multiple elongate spring elements arranged at different angles, each contributing to the overall oscillatory movement. This segmentation allows the system to achieve the required oscillatory function while distributing the space requirements across multiple smaller components rather than one large longitudinal structure
Solution Approach 2:
The spring elements are arranged in a radial pattern around the drive shaft axis, utilizing angular positioning rather than purely longitudinal arrangement. By distributing spring elements at different angles (e.g., 0°, 60°, 120°) around the axis, the system achieves oscillatory movement while minimizing the longitudinal footprint, effectively transitioning from a 1D longitudinal layout to a 2D radial configuration
2Reliability
If traditional rotational springs are used, then oscillatory movement is generated, but additional journaling elements like ball bearings are required increasing device complexity
Solution Approach 1:
The spring elements serve dual functions: they provide the oscillatory restoring force and simultaneously act as journaling elements that guide and constrain the oscillatory movement. This merging of functions eliminates the need for separate ball bearings or other journaling elements, reducing the total number of mechanical components while maintaining reliable oscillatory movement
Solution Approach 2:
The elongate spring elements are designed to perform multiple functions within a single component: they provide elastic restoring force for oscillation, guide the oscillatory path, and constrain movement to the desired degrees of freedom. This multi-functionality reduces device complexity by eliminating the need for separate specialized components for each function
3Adaptability or versatility
If multiple spring elements are arranged at different angles, then stiffness can be adjusted in different spatial directions, but the structural design becomes more complex
Solution Approach 1:
The spring elements are arranged at specific asymmetric angles around the drive shaft axis rather than symmetrically. By positioning springs at angles such as 0°, 60°, and 120°, the system achieves different stiffness characteristics in different spatial directions, allowing optimization of oscillatory behavior while maintaining a relatively simple radial structural pattern that is easier to design and manufacture than more complex three-dimensional arrangements
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 system allows for a compact and cost-effective generation of rotary oscillatory movements with adjustable stiffness in different directions, enabling both rotary and translatory movements, and can be manufactured with leaf springs from sheet metal or plastic, reducing manufacturing costs and enhancing the appliance's structural integrity.
Implementation Method 1
at least two elongate spring elements which are elastic at least in the direction of the rotary oscillatory movement
Data Source
Figure 1
Figure 2
Figure 3~4b
AI summary
The invention relates to an oscillatory system for a drive unit for the generation of a rotary oscil- latory movement having a first oscillatory component and a second oscillatory component able to oscillate with respect to one another around an axis of oscillation. In accordance with the in- vention, the oscillatory system has at least two elongate spring elements which are elastic at least in the direction of the rotary oscillatory movement and which each have two fastening points spaced apart from one another, with one respective fastening point being connected to the first oscillatory component, one respective fastening point being connected to the second oscillatory component and the connection line of the fastening points of at least one spring element and the connection line of the fastening points of at least one other spring element intersecting at an an- gle of intersection. The invention furthermore relates to a drive unit having an electromagnetic drive element in accordance with the invention and an oscillatory system in accordance with the invention and to a small electric appliance having a drive unit in accordance with the invention.