V-Shaped Torsion Spring Nodal Mounting for Toothbrush Drive Train
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Solution Overview
Problem
Existing nodal spring arrangements in electronic toothbrush drive trains face challenges in achieving a desired dynamic response while minimizing stress and wear at the node point, and ensuring a linear response along the length of the V spring.
Innovation Solution
A V-shaped torsion spring member is secured at both ends with a node point midway, connected to a mounting plate that is fixedly attached to the toothbrush housing, using slots to distribute stress and a combination of an insert and shim to provide a stable, low-friction connection that maintains linearity and reduces vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the V spring is fixedly connected to the mounting plate at the node point, then the dynamic response and vibration reduction are improved, but the stress and wear at the contact area increase
Solution Approach 1:
The mounting plate is divided into a plate body and a separate nodal contact portion that protrudes toward the V spring. This segmentation concentrates the connection at a specific nodal point while distributing stress through the plate structure, reducing wear at the contact area while maintaining effective dynamic response.
Solution Approach 2:
The nodal contact portion acts as an intermediary element between the V spring and the plate body. It provides a dedicated contact surface that mediates the force transmission, reducing direct stress concentration on the main plate structure while ensuring reliable dynamic coupling.
2Manufacturing precision
If the V spring is rigidly mounted to achieve linear response, then the response linearity is improved, but the wear and potential for failure increase
Solution Approach 1:
The mounting plate exhibits local quality variation: the nodal contact portion has a specific geometry optimized for minimal contact and reduced wear, while the plate body provides structural support. This localized differentiation allows the system to achieve linear response characteristics without uniform rigid mounting that would cause excessive wear.
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 effectively reduces stress and wear at the node point, ensures a linear response of the V spring, and maintains a stable connection, enhancing the reliability and durability of the drive train assembly.
Implementation Method 1
a V shaped torsion spring member secured at both ends thereof, the V shaped torsion spring member having a node point along the length thereof, approximately midway of the V shaped torsion spring member, wherein in operation the V shaped torsion spring member is excited in and out of phase torsion mode
Implementation Method 2
the mounting plate, which acts as a ground connection for the V-shaped torsion spring bar, is connected to the handle frame/housing, reducing vibrations which would otherwise be transferred to the handle
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A nodally-mounted spring arrangement for a drive train (10) used in an electronic toothbrush having a housing comprises a V shaped spring member (15) secured at both ends so that it can operate in out-of-phase torsion mode along the axial dimension thereof. A mounting plate (26) is connected between a node point (30) along the V shaped spring member and the housing of the toothbrush. The mounting plate member (26) is fixedly connected to the node point (30) of the V shaped spring member and fixedly connected to the housing of the toothbrush, such that rotation of one portion of the V shaped spring member in one direction results in a rotation of the remaining portion of the V shaped spring member in the opposite direction.