Wave Spring Brake Cylinder for Shorter Stroke Packaging

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Solution Overview

Problem

Existing brake cylinders for commercial vehicles face challenges in reducing installation space and optimizing the spring center of the axle, which affects rollover stability and steering angle, while also requiring a reduction in component count to save costs and material.

Innovation Solution

The use of a wave spring as a spring device in the brake cylinder, which surrounds the piston rod, reduces the brake actuation travel and cylinder stroke, allowing for a more compact design by requiring less space compared to traditional round wire springs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If traditional round wire springs are used in brake cylinders, then the spring can generate the required braking force, but the brake actuation travel and cylinder stroke are excessive, increasing installation space requirements

Engineering Contradiction:
Improvebraking forceVSAvoidbrake actuation travel
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The patent changes the geometric parameters of the spring from a traditional round wire spiral form to a wave spring form with specific wave patterns. This parameter change allows the spring to generate the same braking force with significantly reduced travel distance, directly resolving the contradiction between force generation and actuation travel length

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The wave spring uses curved wave patterns instead of straight or simple spiral configurations. The corrugated wave structure allows the spring to compress and extend more efficiently within a shorter axial distance, reducing the brake actuation travel while maintaining the necessary braking force through optimized curvature geometry

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Force

If traditional round wire springs are used in brake cylinders, then the spring can generate the required braking force, but the cylinder stroke is excessive, increasing overall component length and installation space

Engineering Contradiction:
Improvebraking forceVSAvoidcylinder stroke
Core Design Contradiction:
ForceVSLength of stationary object

Solution Approach 1:

The patent transforms the spring geometry from a conventional round wire design to a wave spring design with optimized wave parameters. This parameter change enables the spring to achieve the required force output with a shorter compressed length, thereby reducing the cylinder stroke and overall brake cylinder length

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The wave spring introduces a radial dimension through its corrugated structure, allowing the spring to store and release energy more efficiently. The wave pattern creates multiple compression zones along the radial direction, enabling the spring to generate the necessary braking force within a shorter axial stroke distance

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

3Device complexity

If the number of brake components is reduced to save costs and material, then manufacturing simplicity improves, but the remaining components must be more compact to maintain performance

Engineering Contradiction:
Improvenumber of componentsVSAvoidinstallation space
Core Design Contradiction:
Device complexityVSVolume of moving object

Solution Approach 1:

The wave spring integrates multiple functions into a single component, combining the spring element and the force-generating element into one unified structure. This merging reduces the total number of components needed in the brake cylinder assembly while the compact wave geometry ensures that the remaining components occupy less installation space

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The wave spring serves multiple functions simultaneously: it provides the braking force, acts as a mechanical element for force transmission, and serves as a space-saving structural component. This multi-functionality allows the brake system to maintain performance with fewer components and reduced installation space requirements

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

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 achieves a significant reduction in installation space, weight, and unsprung mass, while enabling efficient generation of braking force and restoring force, and allows for integration into various brake types such as disc and drum brakes.

Implementation Method 1

the spring device is designed to generate a braking force and/or a restoring force for releasing a brake in a stroke direction of the brake cylinder

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4561880B1Brake cylinder for a vehicle brake
Publication Date: 2025.12.31 SAF HOLLAND GMBH
  • EP4561880B1 patent drawingFigure 1~2

AI summary

The invention relates to a brake cylinder for a vehicle brake, in particular a utility vehicle brake, comprising a spring device, wherein the spring device (1) has at least one first section for generating a braking force and/or a restoring force to release a brake in a stroke direction (H) of the brake cylinder, wherein the first section (2) has a main extension extending substantially in a first section plate, wherein a normal of the first section plane is orientated substantially in parallel with the stroke direction (H) and/or deviates from the stroke direction (H) by max. 10°, wherein the first section (2) has, in particular alternating, first sub-sections (3) and second sub-sections (4) along its main extension, wherein the first sub-sections (3) are spaced apart from the first section plane in a positive stroke direction (H) in the unloaded state, and wherein the second sub-sections (4) are spaced apart from the first section plane in a negative stroke direction (H) in the unloaded state, wherein the first and second sub-sections (3, 4) are designed such that, in the loaded state, with the generation of a spring force, they are at a lesser distance from the first section plane than in the unloaded state.