Pump Shaft Sealing Assembly for Precise, Leak-Resistant Liquid Delivery
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Solution Overview
Problem
Existing medical liquid injection devices, particularly for diabetic patients, face challenges in precisely and reliably delivering small amounts of medical liquids due to complex driving mechanisms and fluid leakage issues.
Innovation Solution
A pump design featuring a housing with a shaft assembly and a sealing member having multiple contact regions formed by protrusions, which minimizes fluid leakage and allows precise transmission of driving force through a flexible sealing mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing member with protrusions is used to prevent fluid leakage, then sealing reliability is improved, but friction with the housing inner wall increases
Solution Approach 1:
The sealing member is designed with protrusions that can elastically deform to contact the housing inner wall, creating multiple sealing points. The flexible material allows the protrusions to conform to the housing surface while maintaining sealing effectiveness, resolving the contradiction between sealing reliability and friction by using elasticity to achieve both goals.
2Measurement precision
If the shaft assembly is designed for precise force transmission, then driving force accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the sealing function from the shaft assembly by using a separate sealing member with protrusions that contacts the housing. This separation allows the shaft assembly to focus on force transmission while the sealing member handles sealing, reducing overall device complexity while maintaining precise force transmission capability.
Solution Approach 2:
The sealing member is segmented into multiple protrusions that independently contact the housing inner wall at different points. This segmentation provides multiple sealing points along the longitudinal direction, ensuring reliable sealing without requiring a complex overall sealing structure, thus maintaining simplicity while achieving precise force transmission.
3Reliability
If multiple contact regions are created along the shaft longitudinal direction, then fluid leakage is prevented, but the manufacturing precision requirements increase
Solution Approach 1:
The sealing member uses material elasticity as a key parameter to compensate for manufacturing tolerances. The protrusions are designed with specific elastic properties that allow them to deform and make contact with the housing inner wall even if there are slight variations in positioning, thereby achieving reliable sealing without requiring extremely high manufacturing precision.
Data Source
AI summary
The present disclosure provides a pump including a housing having a shaft hole, a membrane assembly disposed inside the housing, and a shaft assembly mounted on the housing. The shaft assembly includes a shaft inserted into the shaft hole, and a sealing member disposed on an end portion of the shaft and having a plurality of contact regions on an inner surface of the housing along a longitudinal direction of the shaft.