Miniature Pump Motor Shaft Stabilizing Element
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Solution Overview
Problem
Miniature pumps, particularly diaphragm pumps with electric motors having axially displaceable motor shafts, experience vibrations and noise due to axial shaft play, which is challenging to address without compromising design size or performance, especially in medical applications where noise and vibration are undesirable.
Innovation Solution
A stabilizing element is used outside the motor housing to apply axial compressive or tensile forces to the motor shaft, reducing or eliminating axial shaft play, thereby preventing relative movement between the motor shaft and the motor housing, without requiring structural modifications to the electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electric motors with axially displaceable motor shafts are used in miniature pumps, then cost-effectiveness and compact design are improved, but vibrations and noise increase due to axial shaft play
Solution Approach 1:
A stabilizing element is introduced as an intermediary component between the motor shaft and the pump housing. This stabilizing element applies axial preloading force to the motor shaft, preventing axial displacement and eliminating shaft play. The stabilizing element acts as a mediator that transfers the preloading force from the pump housing to the motor shaft, thereby reducing vibrations and noise without modifying the electric motor itself.
Solution Approach 2:
The stabilizing element applies axial preloading force to the motor shaft before the pump operates. This preliminary action counteracts the axial shaft play that would otherwise occur during operation, preventing the motor shaft from displacing axially and thus preventing the generation of vibrations and noise during pump operation.
2Object-generated harmful factors
If axial shaft play is reduced by pretensioning the connecting rod, then vibrations and noise are reduced, but long-term stability deteriorates
Solution Approach 1:
The invention extracts the function of axial shaft stabilization from the connecting rod and places it in a dedicated stabilizing element. By separating this function, the connecting rod can focus on its primary function of transmitting mechanical power, while the stabilizing element independently provides axial preloading. This separation improves long-term stability as the stabilizing element is specifically designed for this purpose and can be optimized independently.
Solution Approach 2:
A dedicated stabilizing element is introduced as an intermediary component specifically for applying axial preloading force to the motor shaft. This stabilizing element is designed solely for this purpose, providing reliable and stable axial constraint without the complications of modifying the connecting rod's primary function, thereby ensuring long-term operational stability.
3Object-generated harmful factors
If the motor shaft is constrained axially, then vibrations and noise are reduced, but the motor shaft's freedom of movement is restricted
Solution Approach 1:
The stabilizing element applies axial preloading force locally to the motor shaft without restricting its rotational freedom. The constraint is applied only in the axial direction where shaft play causes problems, while the motor shaft maintains full freedom of rotation and can still accommodate thermal expansion and manufacturing tolerances. This localized constraint approach reduces vibrations and noise without overly restricting the motor shaft's necessary movements.
Data Source
AI summary
What is illustrated and described is a pump assembly (1) for a pump, particularly for a miniature pump, with an electric motor (2) and with a housing unit (3), wherein the electric motor (2) has a motor shaft (5) passing freely through a motor housing of the electric motor (2) and the motor housing is connected to the housing unit (3), and wherein the motor shaft (5) is supported in the motor housing with an axial shaft play. According to the invention, at least one stabilizing element (6, 13, 14, 16) arranged outside of the motor housing is provided in order to reduce or eliminate the axial play of the motor shaft (5), with an axial compressive force or axial tensile force acting on the motor shaft (3) being applied by the stabilizing element (6, 13, 14, 16) to the motor shaft (5).