Hydrodynamic Retarder Brake Layout for Compact High-Power Braking

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Solution Overview

Problem

Conventional braking devices for motor vehicles, particularly those used in commercial vehicles, are complex, expensive, and require significant installation space due to their electromotive brake systems, which also limit braking power and necessitate additional components like energy storage and control systems.

Innovation Solution

A braking device utilizing a hydrodynamic retarder system with a fluid path, an electric pump, and a directional valve to control fluid flow, allowing for decoupling and coupling of the rotor with the drive shaft, thereby simplifying the system and reducing installation space and costs by eliminating redundant components such as adjusting elements and displacement devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If an electromotive brake system is used, then braking power can be controlled, but the device complexity and installation space increase significantly

Engineering Contradiction:
Improvebraking powerVSAvoidsystem complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines the brake actuator, control valve, and fluid reservoir into an integrated braking device assembly. The brake actuator directly houses the control valve and fluid reservoir, eliminating the need for separate components and reducing overall system complexity while maintaining controlled braking power through the integrated design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The brake actuator serves multiple functions: it acts as the primary braking component, houses the control valve for fluid regulation, contains the fluid reservoir, and provides mounting points for the entire assembly. This multi-functionality reduces the number of separate components needed in the braking system.

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

2Power

If an electromotive brake system with energy storage is used, then braking power can be maintained, but installation space and costs increase

Engineering Contradiction:
Improvebraking powerVSAvoidinstallation space
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent implements a nested configuration where the control valve is positioned inside the brake actuator chamber, and the fluid reservoir is contained within the same housing. This nested arrangement allows multiple components to occupy overlapping or adjacent spaces, significantly reducing the overall installation footprint compared to separate component mounting.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If conventional braking devices are used, then braking function is provided, but maintenance needs and costs increase

Engineering Contradiction:
Improvebraking functionVSAvoidmaintenance needs
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The braking device is designed as a self-contained modular unit with distinct functional sections (brake actuator, control valve, fluid reservoir) that can be serviced independently. The control valve assembly can be accessed and maintained separately from the brake actuator, and the fluid reservoir can be serviced without disassembling the entire braking system, reducing maintenance complexity.

Inventive Principle:
Principle #1Segmentation

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 solution achieves a compact and cost-effective braking system suitable for battery-electric and fuel cell vehicles, with reduced maintenance needs, by integrating a hydraulic system that decelerates the vehicle through fluid dynamics without the complexity and space requirements of traditional electromotive brakes.

Implementation Method 1

At least one pump element (18), in particular an oil pump, is arranged in the fluid path (12) for conveying the fluid through the fluid path (12)

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

At least one valve device (34) is arranged in the fluid path (12), through which fluid can flow, has at least one valve inlet (26) and at least one valve outlet (28) spaced from the valve inlet (26), and is movable between at least two valve positions (30, 32)

Methodology Applied
Scientific EffectValve: Valve

Implementation Method 3

A braking device utilizing a hydrodynamic retarder system with a fluid path, an electric pump, and a directional valve to control fluid flow, allowing for decoupling and coupling of the rotor with the drive shaft

Methodology Applied
Scientific EffectHydrodynamic retarder:

Data Source

PatentEP4384427B1Vehicle brake device
Publication Date: 2025.07.30 DAIMLER TRUCK AG
  • EP4384427B1 patent drawingFigure 1
  • EP4384427B1 patent drawingFigure 2
  • EP4384427B1 patent drawingFigure 3

AI summary

The invention relates to a braking device (10) for a motor vehicle, comprising: a fluid path (12) through which a fluid can flow, having at least two line sections (14, 16), and in which at least one pump element (18) and at least one valve device (34) are arranged, which valve device has a valve inlet (26) and a valve outlet (28) and can be moved between at lest two valve positions (30, 32), and which is fluidically connected to the pump element (18) via the valve inlet (26) by means of a first of the line sections (14); a retarder (38) having a stator (40), a rotor (42) and a retarder inlet (44), via which the retarder (38) is fluidically connected to the valve device (34) via the valve outlet (28) by means of the second of the line sections (16), wherein the valve inlet (26) is fluidically connected to the valve outlet (28) in a first of the valve positions (30), and the valve inlet (26) is not fluidically connected to the valve outlet (28) in the second valve position (32).