Stepping Motor Axial Noise Suppression via Coil Spring
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Solution Overview
Problem
Dimensional variations in stepping motor components can lead to gaps between the rotor and plates, causing axial rattling and noise, which existing solutions attempt to address by adjusting rubber washers, increasing component counts and costs.
Innovation Solution
A stepping motor design featuring a rotor with a shaft, a stator, and a plate with an annular projection that includes a coil spring to elastically press the rotor against another member, absorbing axial movement and reducing noise without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If rubber washers with fixed height dimension are used to absorb axial rattling, then noise suppression is achieved under ideal conditions, but gaps occur during assembly due to dimensional variations, causing noise and requiring multiple washer types which increases cost and complexity
Solution Approach 1:
The patent changes the parameter of the elastic member from fixed height to variable height capability. The elastic member can be compressed in the axial direction to vary its height, allowing a single type of elastic member to accommodate dimensional variations in assembly without requiring multiple types with different fixed heights.
Solution Approach 2:
The patent introduces dynamic adaptability to the elastic member, which can dynamically adjust its compression level and height based on the actual assembly conditions. This dynamic characteristic allows the elastic member to maintain contact between the rotor and plate regardless of dimensional variations, eliminating the need for multiple fixed-height washer types.
2Object-affected harmful factors
If multiple types of rubber washers with different thicknesses are prepared to adjust for dimensional variations, then noise suppression is maintained, but the number of components increases and working efficiency decreases, resulting in cost increase
Solution Approach 1:
The patent makes the elastic member universal by giving it the ability to accommodate various assembly conditions through compression. A single type of elastic member can serve multiple functions: absorbing axial rattling under ideal conditions and compensating for dimensional variations under non-ideal conditions, eliminating the need for multiple specialized washer types.
Solution Approach 2:
The elastic member's compression capability allows it to change its effective height parameter based on assembly needs. This parameter changeability enables one elastic member type to replace multiple fixed-height types, simplifying manufacturing and reducing costs.
3Object-affected harmful factors
If a coil spring is used to elastically press the rotor, then noise suppression is achieved and the structure remains simple, but the coil spring may be damaged by large forces from significant gaps
Solution Approach 1:
The patent implements beforehand cushioning by providing the elastic member within the projection's axial space. The elastic member acts as a cushion that can absorb large forces from significant gaps before they reach the coil spring, protecting the spring from damage while maintaining the simple structure.
Solution Approach 2:
The patent uses a nested structure where the elastic member is placed within the projection, and the coil spring is positioned behind the elastic member. This nesting arrangement allows the elastic member to serve as a protective buffer for the coil spring, absorbing extreme forces while the spring maintains normal noise suppression function.
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 effectively suppresses noise from axial gaps due to dimensional variations while maintaining a simple and cost-effective structure, preventing coil spring damage from large forces.
Implementation Method 1
a coil spring is provided to be interposed between the plate and the rotor in a state in which the coil spring is fitted on the shaft on an inner side of the projection, and to urge the rotor toward another end in the axial direction to elastically press the rotor against another member
Data Source
AI summary
Noise caused by a gap between a rotor and a plate can be suppressed even when there are dimensional variations in members or assembly states. In a configuration of a stepping motor including front side and end side stator assemblies (200, 300), a rotor (400) provided with a rotor member (402) and a shaft (403) that are accommodated in the stator assemblies (200, 300), and a front plate (210) and an end plate (310) that are arranged on both sides of the stator assemblies (200, 300) in an axial direction, and are configured to couple the stator assemblies (200, 300), a projection (700) in an annular shape is provided on a surface of the front plate (210) facing the rotor member (402) to protrude toward the rotor member (402), a coil spring (800) that is interposed between the front plate (210) and the rotor member (402) is accommodated in the inner side of the projection (700), and the rotor (400) is urged toward the end plate (310) by the coil spring to be elastically pressed against the end plate (310).