Cable Drive Mechanism Using Split Screw Rod for Quiet Self-Return
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Solution Overview
Problem
Existing electric cable driving mechanisms with two-stage transmission systems output insufficient force and face issues with noise due to the axial passage of coil springs through screw rods during assembly.
Innovation Solution
The implementation of a three-stage transmission mechanism with a multifunctional screw rod and a coil spring assembly, which includes a spline and external thread section, allows for increased force output and prevents coil spring scratching by facilitating easy mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a two-stage transmission system is used, then the device complexity is reduced, but the output force is insufficient
Solution Approach 1:
The transmission system is divided into three distinct stages: first-stage gear, second-stage gear, and third-stage screw rod nut. Each stage performs a specific function in the power transmission chain, allowing the system to achieve high output force through cumulative mechanical advantage while maintaining modular design benefits
2Ease of manufacture
If a coil spring is mounted axially through a long screw rod, then the assembly process is simplified, but the screw rod is scratched causing abnormal noise
Solution Approach 1:
A dedicated spring installation groove is provided on the screw rod surface, serving as an intermediary structure that guides the coil spring during assembly. This groove prevents direct contact between the spring and the screw rod surface, eliminating scratching and noise generation while maintaining assembly simplicity
Solution Approach 2:
The spring installation groove acts as a protective surface feature that accommodates the coil spring in a controlled manner, preventing metal-to-metal contact and friction that would cause scratching and noise during the assembly process
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 three-stage transmission mechanism outputs a larger force compared to two-stage systems, reduces noise by preventing coil spring scratching, and allows for adaptable force output by selecting motors with different powers.
Implementation Method 1
the coil spring needs to axially pass through a long screw rod when being mounted into the integrated screw rod
Implementation Method 2
a coil spring assembly and a three-stage gear, where the multifunctional screw rod includes a spline and an external thread section
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Provided is an electric cable driving mechanism having a self-return function. The electric cable driving mechanism includes a housing assembly, an electric motor, a three-stage transmission mechanism and a multifunctional nut, where the three-stage transmission mechanism includes a coil spring assembly, the electric motor is fixed to the housing assembly, and the three-stage transmission mechanism and the multifunctional nut are mounted in the housing assembly; and the multifunctional nut includes two cable mounting grooves and is in transmission connection to the electric motor by means of the three-stage transmission mechanism. According to the electric cable driving mechanism having a self-return function of the present disclosure, the three-stage transmission mechanism is used, and outputs a larger force compared with two-stage transmission; and a split multifunctional screw rod is easy to mount, such that mounting of a coil spring during assembly is prevented from scratching the screw rod, and the problem of abnormal noise generated during mounting of the coil spring is solved.