Vehicle Pump Rotor-Impeller Coupling for Low-Resistance Cooling

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Solution Overview

Problem

Existing pump devices suffer from insufficient cooling of the motor unit and electronic control unit due to high flow resistance in separate channels, leading to overheating and limited power consumption, with assembly complexity and cost being additional issues.

Innovation Solution

A pump device design featuring a direct connection between the rotor and impeller with a circumferentially closed annular gap, eliminating the need for separate channels, allowing direct fluid flow for cooling and torque transmission, and incorporating a cooling chamber for enhanced heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If separate channels are provided to guide coolant from the outlet side of the impeller to the rotor chamber, then the motor unit can be cooled, but the flow resistance is high due to narrow and long channels and friction of the rotating rotor

Engineering Contradiction:
Improvecooling efficiencyVSAvoidchannel structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the cooling channel function into the rotor chamber wall structure itself, eliminating the need for separate narrow and long channels. The rotor chamber wall directly guides the coolant from the impeller outlet side to the rotor, reducing flow resistance and simplifying the overall structure while maintaining effective cooling of the motor unit.

Inventive Principle:
Principle #5Merging (Combining)

2Temperature

If separate channels with high flow resistance are used, then the coolant can reach the rotor chamber, but the volume flow of working fluid is limited for the same pressure difference

Engineering Contradiction:
Improvecooling capacityVSAvoidvolume flow of working fluid
Core Design Contradiction:
TemperatureVSQuantity of substance

Solution Approach 1:

By integrating the cooling passage directly into the rotor chamber wall structure, the patent creates a shorter and wider flow path for the coolant. This merging of functions allows significantly higher volume flow of working fluid to reach the rotor chamber for the same pressure difference, thereby increasing the cooling capacity and heat transport potential.

Inventive Principle:
Principle #5Merging (Combining)

3Power

If a shaft is used to transmit torque from the rotor to the impeller, then the rotational movement can be transmitted, but the assembly complexity and manufacturing cost increase

Engineering Contradiction:
Improvetorque transmissionVSAvoidassembly complexity
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent employs asymmetric direct coupling between the rotor and impeller, where the impeller is directly mounted on the rotor shaft with asymmetric positioning features. This asymmetric design eliminates the need for separate shaft components while maintaining effective torque transmission, thereby simplifying the assembly process and reducing manufacturing complexity.

Inventive Principle:
Principle #4Asymmetry

4Device complexity

If the rotor is directly connected to the impeller in a rotationally fixed manner, then torque can be transmitted directly without a shaft, but the assembly precision requirements increase

Engineering Contradiction:
Improvenumber of componentsVSAvoidassembly precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent incorporates preliminary positioning features directly into the rotor and impeller designs, such as locating pins, recesses, and asymmetric mounting surfaces. These pre-designed positioning elements ensure accurate alignment and precise assembly when the impeller is directly coupled to the rotor, thereby reducing the actual assembly precision requirements despite the direct connection.

Inventive Principle:
Principle #10Preliminary action

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 achieves lower flow resistance, improved cooling efficiency, reduced assembly complexity, and cost-effectiveness by enabling larger fluid volume flow for better heat transport and eliminating the need for additional components.

Implementation Method 1

the working fluid can enter the rotor chamber for cooling the motor unit and in particular the electronic control unit

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

cooling the rotor as well as the neighboring stator and the electronic control unit

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

an impeller for transferring energy to a working fluid, such as a coolant

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4685354A1Pump device and method of assembly
Publication Date: 2026.01.28 HELLA GMBH & CO KGAA
  • EP4685354A1 patent drawingFigure 1
  • EP4685354A1 patent drawingFigure 2
  • EP4685354A1 patent drawingFigure 3~4

AI summary

Pump device (100) for a fluid circuit of a vehicle comprising at least a motor unit (1) with a stator (10) and a rotor (11) and an electronic control unit (12); and a housing unit (3) with a fluid chamber (30) with an inlet (E) and an outlet (A) and a dry chamber (31); wherein the stator (10) and the electronic control unit (12) are arranged in the dry chamber (31); and wherein the fluid chamber (30) comprises a rotor chamber (301) and an impeller chamber (302), which are connected to one another by an opening (303); and wherein the rotor (11) is arranged in the rotor chamber (301); and an impeller (2) for transmitting energy to a working fluid (F), wherein the impeller (2) is arranged in the impeller chamber (302) and is connected to the rotor (11) in a rotationally fixed manner. The rotor (11) is directly connected to the impeller (2) in a rotationally fixed manner, so that a circumferentially closed annular gap (R) results at the opening (303), whereby the working fluid (F) can enter the rotor chamber (301) for cooling the motor unit (1) and in particular the electronic control unit (12).