Laundry Pump Impeller-Rotor Synchronization to Reduce Torque Loss

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Solution Overview

Problem

In laundry care appliances, the torque introduced by the drive is not matched to the hydraulic output torque, leading to suboptimal torque transmission, reduced efficiency, and shorter service life due to arbitrary rotational positioning between the magnetized rotor and stator of the drain pump, resulting in inefficient energy use.

Innovation Solution

The hydraulic design of the pump impeller is synchronized with the electrical design of the pump drive by matching the number of pole pairs of the drive to the number of impeller blades, ensuring that torque peaks on the drive side coincide with output torque peaks, thereby optimizing torque transmission and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the rotational positioning between the drive and pump housing is carried out arbitrarily according to production engineering aspects, then the manufacturing process is simplified and easier to implement, but the torque transmission becomes suboptimal and pump efficiency is reduced

Engineering Contradiction:
Improveease of manufactureVSAvoidpump efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The pump impeller is pre-positioned in the pump housing during manufacturing with a predetermined angular relationship. This preliminary positioning ensures that torque peaks from the drive coincide with torque peaks from the impeller-housing interaction, optimizing torque transmission without requiring complex adjustments during assembly or operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the angular position parameter of the pump impeller relative to the pump housing to an optimized value. By setting a specific angular relationship between the impeller and housing, the system achieves constructive interference between drive torque and hydraulic torque, thereby improving pump efficiency while maintaining manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the drive torque is not matched to the hydraulic output torque, then the drive design is simpler and more flexible, but the service life of the pump and drive is reduced due to suboptimal torque transmission

Engineering Contradiction:
Improvedrive design complexityVSAvoidservice life
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The optimal angular positioning between the pump impeller and pump housing is predetermined during the design and manufacturing phase. This preliminary action ensures that the torque characteristics are optimized from the start, avoiding the need for complex adaptive mechanisms while extending the service life of the pump and drive through improved torque transmission.

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If the pole pairs of the drive are matched to the impeller blades to synchronize torque peaks, then the torque transmission and energy efficiency are optimized, but the drive and pump design becomes more complex and less flexible

Engineering Contradiction:
Improveenergy efficiencyVSAvoiddrive and pump design complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The invention optimizes the angular position parameter of the pump impeller relative to the pump housing to achieve constructive interference between drive torque and hydraulic torque. This parameter change improves energy efficiency by ensuring torque peaks coincide, while maintaining relatively simple drive and pump designs through a straightforward geometric relationship.

Inventive Principle:
Principle #35Parameter changes

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

This synchronization enhances the overall efficiency of the pump, reduces power reserves needed in the drive, and minimizes noise caused by load changes, leading to improved performance and reduced costs while maintaining high concentricity of the drive and pump unit.

Implementation Method 1

an electric, multi-phase pump drive with flexible speed, with a stator equipped with electric, static field windings to build up a rotating magnetic field to drive a magnetic rotor

Methodology Applied
Scientific EffectRotating magnetic field: Electromagnetic Induction

Implementation Method 2

a pump impeller with impeller blades, which is designed to convey the fluid from the fluid inlet to the fluid outlet

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3722611B1Pump for a laundry care machine
Publication Date: 2022.11.23 BSH HAUSGERATE GMBH
  • EP3722611B1 patent drawingFigure 1
  • EP3722611B1 patent drawingFigure 2a~2b
  • EP3722611B1 patent drawingFigure 3

AI summary

The present invention relates to a laundry care device (1100) with a pump (800), comprising: a pump pressure chamber (801) with fluid inlet (802) (suction port) and fluid outlet (803) (pressure port); a pump impeller (804) with impeller blades (807) freely rotatable in the pump chamber (801), which is configured to convey the fluid from the fluid inlet (802) to the fluid outlet (803), wherein the pump pressure chamber (801) has a constriction (813) at the fluid outlet (803) at the transition between the pressure port and the pump housing tongue (singularity or discontinuity), wherein a pressure peak (504) is created in the fluid when a respective impeller blade (807) passes the constriction (813);an electric pump drive (805) with a stator (808) equipped with electrical windings (809) for generating a rotating magnetic field (312, 412) for driving a freely rotatable magnetic rotor (812) within the stator (808), which is configured to drive the pump impeller (804), wherein a torque (100) acts on the rotor (812) which has a periodic fluctuation depending on a rotation angle of the rotor (812) with respect to the windings (809) of the stator (808). The rotor (812) is structurally coupled (806) to the pump impeller (804), the coupling (806) being formed by a shaft, to cause a position of the pump impeller (804) at a rotation angle of the rotor (812) at which a peak of the torque (100) occurs, at which the pressure peak (504) arises in the fluid.