Domestic dishwasher

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Solution Overview

Problem

Existing household dishwashers face challenges in designing a spray arm system that is both hydraulically efficient and mechanically robust, particularly due to the integration of drive components that can interfere with water flow and complicate maintenance.

Innovation Solution

A dishwasher design where the drive shaft and spray arm axes are parallel and spaced apart, utilizing a gearbox to transmit torque, with a pump housing and spray arm toothing for positive engagement, allowing for a drive unit that is separate from the spray arm, and incorporating a fluid-permeable gearbox housing for easy cleaning and protection against contamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the drive components are integrated directly with the spray arm, then the mechanical connection is stronger, but the water flow is deflected and the design becomes more complex

Engineering Contradiction:
Improvemechanical connection strengthVSAvoiddesign complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The drive unit is segmented from the spray arm, with the drive shaft positioned at a different location than the spray arm axis. This separation allows the spray arm to remain free of drive components, simplifying its design while maintaining strong mechanical connection through the gear engagement system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A gear mechanism acts as an intermediary between the drive shaft and the spray arm. The gear on the drive shaft engages with the spray arm toothing, transmitting torque while allowing the drive components to be positioned separately from the spray arm, thus reducing design complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the drive shaft and spray arm axes are coincident, then the structure is more compact, but the water flow from the circulation pump is deflected

Engineering Contradiction:
Improvestructural compactnessVSAvoidwater flow efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The drive shaft axis is positioned in a different spatial dimension than the spray arm axis, specifically at a distance away from it. This dimensional separation prevents the drive shaft from interfering with the water flow path from the circulation pump to the spray arm, maintaining hydraulic efficiency while achieving a compact overall structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Power

If the spray arm is directly driven, then the torque transmission is more direct, but the spray arm cannot be kept free of drive components

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidspray arm design simplicity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The drive system is segmented into a drive unit with a drive shaft and a separate spray arm. The drive shaft is positioned at a distance from the spray arm axis, and torque is transmitted through a gear mechanism that engages with the spray arm toothing, allowing the spray arm to remain free of integrated drive components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A gear mechanism serves as an intermediary for torque transmission between the drive shaft and the spray arm. This intermediary system maintains efficient power transmission while keeping the spray arm design simple and free of embedded drive components.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 design provides a simpler, more hydraulically efficient, and robust spray arm system that maintains water flow integrity and facilitates easy maintenance by preventing contamination and allowing for effective cleaning of the gearbox components.

Implementation Method 1

the spray arm comprises a spray arm toothing into which the drive device engages positively for torque transmission

Methodology Applied
Scientific EffectPositive engagement (mechanical tooth engagement): Gear

Implementation Method 2

the wash water and/or fresh water flowing from the household dishwasher's circulation pump to the spray arm

Methodology Applied
Scientific EffectPump: Pump

Data Source

PatentEP4003126B1Domestic dishwasher
Publication Date: 2026.03.25 BSH HAUSGERATE GMBH
  • EP4003126B1 patent drawingFigure 1
  • EP4003126B1 patent drawingFigure 2
  • EP4003126B1 patent drawingFigure 3

AI summary

The invention relates to a domestic dishwasher (1) comprising a washing container (2), a spray arm (16) for applying washing liquor and/or fresh water (F) to the dishwasher load held in the washing container (2), and a drive system (31) for actively driving the spray arm (16), an axis of rotation (34) of a drive shaft (33) of the drive system (31) and an axis of rotation (26) of the spray arm (16) running in parallel and at a distance from one another.