Rotor Fluid Channels for Integrated Electric Machine Braking

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Solution Overview

Problem

Current electric machines for vehicles, particularly heavy-duty trucks, require improved braking efficiency, as existing braking systems are not sufficient for safe descent on long slopes at high speeds.

Innovation Solution

An electric machine with a fluid-based brake arrangement featuring a radial fluid channel segment within the rotor, allowing brake fluid to accelerate and generate a braking torque, providing a simple and reliable braking mechanism with reduced space requirements and enhanced control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional auxiliary braking device (retarder) is used for heavy-duty vehicles, then braking function is provided, but the device occupies additional space and increases system complexity

Engineering Contradiction:
Improvebraking efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brake arrangement is integrated directly into the rotor of the electric machine, merging the braking function with the existing motor structure. This eliminates the need for a separate auxiliary braking device, reducing system complexity while maintaining reliable braking efficiency through the fluid-based braking mechanism within the rotor channels.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a separate auxiliary braking device is installed, then braking function is achieved, but space occupancy increases

Engineering Contradiction:
Improvebraking functionVSAvoidspace occupancy
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The braking system is merged with the rotor structure, utilizing the existing space within the rotor for brake fluid channels. This integration eliminates the need for separate braking components, significantly reducing space occupancy while maintaining effective braking function through the accelerated brake fluid generating reaction force.

Inventive Principle:
Principle #5Merging (Combining)

3Force

If conventional braking systems are used, then basic braking is provided, but braking efficiency is insufficient for high-speed descent

Engineering Contradiction:
Improvebraking torqueVSAvoidbraking efficiency
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The invention employs a fluid-based braking mechanism where brake fluid is accelerated through channels in the rotating rotor, generating high braking torque via reaction force. This hydraulic approach provides superior braking efficiency for high-speed descent compared to conventional mechanical braking systems, as the braking force scales with rotational speed.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The braking mechanism utilizes the periodic rotation of the rotor to continuously accelerate brake fluid through the channels, generating sustained high braking torque during descent. The rotating motion creates continuous fluid acceleration and reaction force, providing reliable braking efficiency that increases with rotational speed.

Inventive Principle:
Principle #19Periodic 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 fluid-based brake arrangement enhances braking efficiency, reduces space occupancy, and allows for higher recuperation power compared to traditional systems, offering improved control and reliability.

Implementation Method 1

acceleration of brake fluid in the at least one radial fluid channel segment causes a reaction force exerting a braking torque on the rotor

Methodology Applied
Scientific EffectReaction force: Reaction (physics)

Data Source

PatentEP4011720B1An electric machine for a vehicle
Publication Date: 2023.08.30 VOLVO TRUCK CORP
  • EP4011720B1 patent drawingFigure 1~2
  • EP4011720B1 patent drawingFigure 3a
  • EP4011720B1 patent drawingFigure 3b

AI summary

The present invention relates to an electric machine (10) comprising a rotor (3), a stator (4), and a fluid-based brake arrangement (2) for said rotor, said fluid-based brake arrangement having a fluid circuit (20) for transporting a brake fluid (30), said fluid circuit comprising a fluid channel arrangement (22) having at least one radial fluid channel segment (24) extending radially through a part of said rotor so as to allow for directing brake fluid from an inner radial rotor side to an outer radial rotor side, whereby, during rotation of said rotor about an axial centre axis, acceleration of brake fluid in said at least one radial fluid channel segment causes a reaction force exerting a braking torque on the rotor.