Pump for discharging a liquid and household appliance comprising such a pump
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Solution Overview
Problem
Conventional liquid discharge pumps, such as those in dishwashers and washing machines, face issues with hair, particles, and fibers accumulating on the drive shaft during high-speed operation, leading to impaired drainage performance due to the play between the impeller and the front end cap.
Innovation Solution
The design incorporates an annular groove in the front end cap and an annular impeller extension that creates an axial play, allowing the impeller to move axially and preventing foreign matter from accumulating by forming a curvaceous channel that guides these contaminants away from the drive shaft, ensuring high-speed operation and improved discharge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If axial play is provided between the impeller and front end cap to ensure free rotation, then the impeller can rotate freely at high speed, but foreign matter accumulates on the drive shaft and impairs drainage performance
Solution Approach 1:
An annular groove is introduced as an intermediary structure between the impeller and front end cap. This groove receives foreign matter (hair, particles, fibers) that would otherwise accumulate on the drive shaft, acting as a mediator that redirects contaminants into a designated collection area where they cannot interfere with the rotation or drainage function
Solution Approach 2:
The harmful factor (foreign matter) is extracted from the critical rotation zone by providing a separate annular groove space. The groove effectively separates the contamination pathway from the drive shaft area, allowing the drive shaft to remain clean while the groove collects all foreign matter that enters the axial play space
2Reliability
If axial play is reduced to prevent foreign matter accumulation, then drainage performance is maintained, but the impeller cannot rotate freely at high speed
Solution Approach 1:
The solution moves the problem from the radial dimension to the axial dimension by creating an annular groove in the axial direction. Instead of reducing the radial clearance, the invention utilizes the axial space to create a three-dimensional contamination collection zone that does not interfere with radial rotation or axial drainage flow
3Stability of the object's composition
If the impeller is firmly fixed on the drive shaft, then rotational stability is improved, but foreign matter easily accumulates and prevents high-speed operation
Solution Approach 1:
The space between the impeller and front end cap is segmented into functional zones: a clean rotation zone for the drive shaft and impeller, and a contaminated zone in the annular groove for foreign matter collection. This segmentation allows the impeller to remain firmly fixed for stability while the groove captures all foreign matter that enters the axial play region
Data Source
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AI summary
The present invention relates to a pump for discharging a liquid, comprising a motor compartment, an electric motor with a drive shaft located within the motor compartment, and an impeller mounted on the drive shaft, wherein there is axial play between a front end cap of the motor compartment and the impeller. The invention provides that an annular groove is formed in the front end cap of the motor compartment and that the impeller has an annular extension extending towards the annular groove. The provision of the annular impeller extension and the corresponding annular groove ensures that, during high-speed rotation of the impeller in the liquid when the pump is operating for discharging a liquid, hair, particles, fibers, or the like contained in the liquid are effectively removed.It is difficult for foreign objects to enter the axial clearance between the front end cap of the motor compartment and the impeller via a channel formed by the annular impeller extension and the corresponding annular groove. This prevents such foreign objects from accumulating or twisting on or around the drive shaft, which would impede high-speed rotation of the drive shaft during operation and impair the pump's discharge performance.