Motor Pump Unit Cooling Channel Design

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Solution Overview

Problem

Existing motor pump units for high-pressure cleaning devices are costly to manufacture and assemble, and they pose a risk to users due to potential leaks in the cooling channel, which can expose live components to coolant liquid.

Innovation Solution

A motor pump unit design featuring two housing parts that form a cooling channel and a drainage channel, where the cooling channel is arranged radially outside the drainage channel, preventing direct access to live components in case of a leak, and using sealing elements for a secure, liquid-tight connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If liquid cooling is provided for the electric motor by embedding a steel tube in the housing wall, then cooling effectiveness is improved, but manufacturing effort and costs increase considerably

Engineering Contradiction:
Improvemotor cooling effectivenessVSAvoidmanufacturing effort and cost
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The cooling channel is integrated directly into the motor housing structure itself, merging the cooling function with the housing. The housing walls form the cooling channel passages, eliminating the need for separate steel tubes or complex cooling components, thereby reducing manufacturing complexity while maintaining effective liquid cooling of the motor

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor housing serves dual functions: it provides structural protection for the motor components and simultaneously acts as the cooling channel structure. The housing walls are designed to contain and guide the cooling liquid, making the housing a multi-functional component that eliminates the need for separate cooling system components

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If a plastic hood is placed on the motor housing to form a cooling cavity, then compact design is achieved, but assembly complexity increases due to additional assembly steps

Engineering Contradiction:
Improvemotor pump unit compactnessVSAvoidassembly complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The cooling channel is merged with the motor housing structure itself rather than being formed by a separate plastic hood. The housing walls contain the cooling liquid passages, integrating the cooling function into the existing housing without requiring additional components or assembly steps

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the cooling channel is surrounded by the motor housing without a drainage channel, then manufacturing is simplified, but user safety is compromised in case of leakage

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiduser safety risk from coolant leakage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The internal volume of the motor housing is segmented into functionally distinct zones: the cooling channel for heat dissipation, the drainage channel for leak collection, and the live component area for motor components. This segmentation ensures that coolant leakage is contained to specific zones and cannot directly contact live components, enhancing safety while maintaining manufacturing simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drainage channel acts as an intermediary barrier between the cooling channel and the live motor components. It serves as a safety buffer zone that intercepts any leaking coolant, preventing direct contact with electrical components and protecting user safety without adding complex safety systems

Inventive Principle:
Principle #24Intermediary (Mediator)

4Temperature

If air cooling is used with considerable heat exchanger surfaces, then cooling capability is achieved, but spatial extension increases the device size

Engineering Contradiction:
Improvemotor cooling capabilityVSAvoiddevice spatial extension
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

The patent transitions from air cooling to liquid cooling for the motor. Liquid cooling channels are formed within the motor housing walls, allowing efficient heat transfer from the motor to the circulating liquid. This hydraulic cooling system achieves effective motor cooling without requiring large external heat exchanger surfaces, thereby maintaining compact device dimensions

Inventive Principle:
Principle #29Pneumatics and hydraulics

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

The design reduces manufacturing costs and simplifies assembly while ensuring user safety by directing any coolant leak away from live components, preventing electrical hazards.

Implementation Method 1

the electric motor is often cooled by an air flow that is preferably directed past the outside of the motor housing

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a cleaning liquid, preferably water, can be pressurized and then directed onto an object to be cleaned

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP2745011B1Motor-pump-unit
Publication Date: 2017.05.24 ALFRED KARCHER SE & CO KG
  • EP2745011B1 patent drawingFigure 1
  • EP2745011B1 patent drawingFigure 2

AI summary

The invention relates to a motor pump unit (10) comprising an electric motor (22) and a pump (12). The electric motor has a motor housing (28), on the outside of which a cooling channel (62) is disposed. The pump (12) has a suction inlet (24) and a pressure outlet (26). Liquid to be pressurised can be fed to the suction inlet (24) via the cooling channel (62). In order to produce and mount the motor pump unit (10) in a cost-effective manner, the motor housing (28) has a first and a second housing part (38, 40) which can be connected to one another so as to be liquid-tight and form the cooling channel (62) therebetween.