Rotor Assembly End-Surface Damping for Motor Noise Reduction
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Solution Overview
Problem
Existing rotor assemblies with vibration damping materials between the rotor core and rotation shaft suffer from poor noise reduction and vibration damping due to limited material amount, material mismatch leading to reliability issues, and a complex production process with high defective rates.
Innovation Solution
A rotor assembly design featuring a rotor core with magnetic grooves and a rotation shaft hole, where a viscoelastic vibration damping member is integrated on the rotor core's end surfaces and interacts with the rotation shaft through a transmission member, avoiding rigid connections and allowing for increased material usage, improved thermal expansion compatibility, and simplified production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vibration damping material is filled between rotor core and rotation shaft, then electromagnetic vibration and noise are reduced, but the material amount is limited due to small gap, resulting in poor noise reduction and vibration damping
Solution Approach 1:
The patent transitions from radial vibration damping (between rotor core and shaft) to axial vibration damping (at end surfaces of rotor core). By placing vibration damping members axially at the end surfaces, the design utilizes the axial dimension to achieve both large material volume and effective vibration damping without being constrained by the limited radial gap.
2Object-affected harmful factors
If injection molding member and vibration damping ring are made of different materials, then vibration damping is achieved, but gap formation occurs due to different heat expansion coefficients, causing reliability problems
Solution Approach 1:
The patent employs homogeneity by making both the injection molding member and vibration damping member from the same material (viscoelastic material). This eliminates the heat expansion coefficient mismatch problem, preventing gap formation and ensuring reliable connection during thermal cycles, while maintaining effective vibration damping.
Solution Approach 2:
The patent uses composite material properties by selecting a viscoelastic material that combines the characteristics of both injection molding materials (formability, strength) and vibration damping materials (damping capacity, thermal expansion compatibility). This single material satisfies multiple requirements simultaneously.
3Ease of manufacture
If injection molding member is used for vibration damping, then production is simplified, but the damping capacity is insufficient, resulting in poor noise suppression effect
Solution Approach 1:
The patent selects a viscoelastic material with specific damping characteristics for both the injection molding member and vibration damping member. This material possesses high damping capacity while remaining suitable for injection molding, thereby achieving both simplified production and effective noise suppression through increased material volume.
4Object-affected harmful factors
If two steps of injection molding and placing vibration damping ring are performed, then vibration damping is achieved, but the process becomes complicated and defective rate increases in mass production
Solution Approach 1:
The patent merges the injection molding process and vibration damping member installation into a single integrated step. The vibration damping member is injection molded directly onto the rotor core end surface, eliminating the separate placement operation and reducing process complexity and defective rate while maintaining effective vibration damping.
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 enhances noise reduction, vibration damping, and reliability by increasing the vibration damping material amount, improving the rotation effect, and reducing production complexities and defective rates.
Implementation Method 1
a vibration damping member (60) made of a viscoelastic material
Implementation Method 2
to absorb an electromagnetic force wave, thereby reducing the noise of the motor and realizing a vibration damping
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A rotor assembly (100) and a motor. The rotor assembly (100) comprises a rotor iron core (10), a permanent magnet (20), a rotating shaft (30), a first end vibration damping member (61), and a first transmission piece (51). The rotor iron core (10) is provided with a magnet recess (102) and a rotating shaft hole (101); the permanent magnet (20) is provided in the magnet recess (102); the rotating shaft (30) is provided in the rotating shaft hole (101); a gap is formed between the rotating shaft (30) and the rotor iron core (10); a first end and a second end of the rotating shaft (30) extend out of the rotating shaft hole (101); the first end vibration damping member (61) is provided on a first end face of the rotor iron core (10) and connected to the rotor iron core (10); a transmission piece is provided in the first end vibration damping member (61); the first transmission piece (51) mates with the rotating shaft (30); the rotor iron core (10) at least drives the rotating shaft (30) by means of the first end vibration damping member (61) and the first transmission piece (51). According to the rotor assembly (100), the material amount of the vibration damping member is large, the noise reduction and vibration damping effects are good, and reliability is high.