Motor Worm Shaft Coupling Noise Reduction
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Solution Overview
Problem
Conventional motors with a worm shaft and worm wheel speed reduction mechanism experience uncontrollable movements of the worm shaft due to imperfect alignment, leading to noise generation when the worm shaft strikes the coupling hole's inner surface.
Innovation Solution
Incorporating circumferential and radial buffer portions made of rubber or plastic within the coupling portion between the worm shaft and rotary shaft, which compress and deform to prevent uncontrollable movements and absorb inertial forces, thereby reducing noise and ensuring smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If clearances are provided between the coupling hole inner surface and coupling projection, then the inertial force can release bound teeth effectively, but uncontrollable movements occur causing noise
Solution Approach 1:
A buffer portion is introduced as an intermediary element between the coupling hole inner surface and the coupling projection. This buffer portion absorbs shocks and prevents direct contact between the hard surfaces, thereby eliminating noise while preserving the clearance function for releasing bound teeth through inertial force.
Solution Approach 2:
The buffer portion is pre-installed in the coupling portion to provide cushioning before any harmful contact occurs. When the rotary shaft rotates and generates inertial force, the buffer portion is compressed first, preventing the coupling projection from directly striking the coupling hole inner surface, thus preventing noise generation while maintaining the ability to release bound teeth.
2Manufacturing precision
If the worm shaft is directly coupled to the rotary shaft, then alignment precision is high, but uncontrollable movements still occur due to imperfect alignment
Solution Approach 1:
The coupling structure changes from a rigid direct connection to a compliant connection with a buffer portion. This parameter change allows the system to tolerate misalignment while preventing harmful movements. The buffer portion deforms to accommodate alignment variations, converting rigid constraints into flexible ones that prevent uncontrollable movements.
Solution Approach 2:
The coupling system transitions from a static rigid connection to a dynamic compliant connection. The buffer portion can deform elastically under load, allowing the coupling to adapt to misalignment dynamically. This dynamic behavior prevents the transmission of uncontrollable movements while maintaining operational reliability.
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 buffer portions effectively suppress noise by preventing the worm shaft from moving uncontrollably and ensuring the inertial force is managed, allowing for smooth operation and release of bound teeth between the worm shaft and worm wheel.
Implementation Method 1
The inner surface of the coupling hole and the coupling projection are configured to be contactable with each other in the circumferential direction while compressing and deforming the circumferential buffer portion in the circumferential direction
Implementation Method 2
A circumferential buffer portion is located in the circumferential clearance. A radial buffer portion is located in the radial clearance
Data Source
AI summary
A coupling portion is provided on either a rotary shaft or a worm shaft in an integrally rotational manner, said coupling portion for connecting the rotary shaft to the worm shaft and having a coupling hole therein. The coupling projection provided on the other of the rotary shaft and the worm shaft is inserted in the coupling hole. A circumferential clearance and a radial clearance are formed between the inner surface of the coupling hole and the coupling projection. Circumferential buffer portions are interposed in the circumferential clearance, and radial buffer portions are interposed in the radial clearance. The inner surface of the coupling hole and the coupling projection are arranged such that the circumferential buffer portions are compressed to deform in the circumferential direction whereby to allow the buffer portions to be brought into contact with each other when the rotary shaft is rotating.