Electric Motor Stator Spring Mounting for Noise Reduction
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Solution Overview
Problem
Electric motors, particularly those with internal rotors, are often noisy due to the coupling of the stator and motor housing made from materials with different rigidity and thermal expansion coefficients, leading to deformation and relative movement, which amplifies noise when heated.
Innovation Solution
A method where the stator is frictionally fixed in the motor housing using a spring element, and the free spaces within the stator are partially or fully filled with a hardening casting material, except for the rotor's receiving space, to create a stable and noise-reducing encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the stator is made from electrical steel sheets and the motor housing is made of aluminum, then the motor achieves high power density and lightweight construction, but the stator deforms into an oval shape during operation causing audible noise
Solution Approach 1:
The patent applies beforehand cushioning by pre-tensioning spring elements in a circumferential groove of the motor housing before the stator is inserted. These spring elements create a frictional connection that compensates for thermal expansion differences and prevents the stator from deforming into an oval shape during operation, thereby eliminating the acoustic noise that would otherwise be generated by the stator hitting the motor housing
2Power
If the stator is continuously deformed into an oval shape during operation, then the motor achieves high power density, but the stator hits against the round motor housing causing measurable noise
Solution Approach 1:
The spring elements are pre-tensioned before stator insertion to create a frictional connection that maintains the stator's circular shape during operation. This frictional connection prevents the stator from deforming into an oval under magnetic forces, thereby maintaining manufacturing precision (circular shape) while operating at high power density
Solution Approach 2:
The spring elements act as an intermediary between the stator and the motor housing. They create a frictional connection that transmits forces uniformly around the stator's circumference, preventing deformation while allowing the stator to operate at high power density without hitting the motor housing
3Temperature
If the motor housing is heated from the outside, then the motor housing expands more than the stator due to different thermal expansion coefficients, but this creates greater relative expansion and amplifies acoustic behavior
Solution Approach 1:
The spring elements are pre-tensioned before heating occurs to create a frictional connection that compensates for thermal expansion differences. When the motor housing is heated from the outside and expands more than the stator, the frictional connection maintained by the spring elements prevents excessive relative expansion and the resulting acoustic noise
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
This method significantly reduces acoustic noise and mechanical deformations, maintains mechanical strength, and lowers winding temperatures, enhancing the electric motor's performance and reducing the risk of overheating.
Implementation Method 1
the stator is frictionally fixed in the motor housing in a first step by means of at least one spring element
Implementation Method 2
the stator is frictionally fixed in the motor housing in a first step by means of at least one spring element
Implementation Method 3
the free spaces within the stator, with the exception of a receiving space for a rotor, are at least partially, in particular completely, filled with a hardening pouring material
Implementation Method 4
This is particularly the case when the stator and the motor housing are made of different materials, in particular materials of different rigidity and/or materials with different coefficients of thermal expansion
Data Source
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AI summary
The invention relates to a method for manufacturing an electric motor in which a stator is mounted in a motor housing. The method is characterized in that, in a first step, the stator is frictionally fixed in the motor housing by means of a spring element, and that, in a second step, the remaining space between the stator and the motor housing and the free spaces within the stator, with the exception of a receiving space for a rotor, are at least partially filled with a hardening casting material.