Step Motor Output Gear Stability via Radial Bearing Protrusion
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Solution Overview
Problem
The assembly of step motors for vehicle indicators is hindered by the instability of the output gear during manufacturing, leading to potential falling issues due to offset support points and radial gaps, which decreases productivity.
Innovation Solution
Incorporating a protrusion from the radial bearing that extends beyond the first reduction gear in the axial direction, providing additional support to the output shaft and stabilizing the final gear, thus preventing the output gear from falling during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the output gear is supported only by the radial bearing on one side, then the device complexity is reduced, but the output gear becomes unstable during assembly and may fall
Solution Approach 1:
The support for the output gear is extended from a single-point radial support to a distributed support system that includes both radial support (from the bearing) and axial support (from the protrusion). This dimensional extension provides stability without significantly increasing complexity.
Solution Approach 2:
The protrusion acts as an intermediary support element between the radial bearing and the output gear. It transfers and distributes the support forces, preventing the output gear from falling during assembly while maintaining a relatively simple overall structure.
2Reliability
If the final gear is positioned to mesh with the reduction gear, then the gear mechanism functions properly, but the output gear becomes difficult to assemble and may fall due to offset support points
Solution Approach 1:
The protrusion is pre-positioned on the radial bearing before the final gear meshing is attempted. This preliminary support structure is already in place to prevent the output gear from falling, allowing the final gear and reduction gear to be meshed without assembly difficulties.
Solution Approach 2:
The protrusion serves as a mediating support element that resolves the conflict between gear meshing requirements and assembly ease. It provides the necessary support during the meshing process, enabling both reliable gear engagement and easy assembly.
3Manufacturing precision
If the radial bearing supports the output shaft at a single point, then the manufacturing precision requirements are reduced, but the output gear alignment with the rotation center line becomes unstable
Solution Approach 1:
The support system is extended from a single radial point to include an axial dimension (the protrusion). This creates a distributed support zone rather than a single point, providing alignment stability without requiring extremely high manufacturing precision at any single location.
Data Source
AI summary
A step motor that rotationally drives a rotating body includes: an output gear having an output shaft that rotates around a rotation center line together with the rotating body, and a final gear extending radially outward from the output shaft; a radial bearing having an inner circumference side that radially supports the output shaft, on one side of the final gear in an axial direction; a reduction gear mechanism having a first reduction gear meshed with the final gear, and a second reduction gear meshed with the first reduction gear on the one side of the final gear in the axial direction; and a protrusion protruding from the radial bearing toward the other side in the axial direction, in a specific area extending from a longitudinal cross section of the output gear including the rotation center line to an opposite side away from the first reduction gear.