Compact Master Cylinder Fitting with Bushing Guidance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing master fittings for hydraulic actuating elements are complex to assemble and manufacture, and their long design along the cylinder axis results in a large installation space, making them unsuitable for vehicles with small handlebars, particularly restricting operation for users with small hands.

Innovation Solution

A compact master fitting design with a piston-cylinder pairing where the inner diameter of the cylinder is greater than the outer diameter of the piston, incorporating a bushing for secure assembly and a compensating chamber with an overflow channel to manage hydraulic fluid volume changes, allowing for easy assembly and operation with adjustable reach to accommodate different hand sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cylinder inner diameter is made equal to or slightly larger than the piston outer diameter for easy assembly, then assembly ease is improved, but piston guidance reliability deteriorates

Engineering Contradiction:
Improveassembly easeVSAvoidpiston guidance reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

A bushing is introduced as an intermediary component between the cylinder and piston. The bushing has an outer diameter that fits within the cylinder's inner diameter and an inner diameter that matches the piston's outer diameter, providing a precise guidance surface for the piston while maintaining ease of assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cylinder bore is divided into two functional sections: an upper section with a larger diameter for easy piston insertion, and a lower section containing the bushing for precise piston guidance during operation. This segmentation allows each section to optimize for its specific function.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a bushing is added to reduce the effective cylinder diameter for secure piston guidance, then piston guidance reliability is improved, but device complexity increases

Engineering Contradiction:
Improvepiston guidance reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bushing is integrated with the piston assembly rather than being a separate component installed in the cylinder. The bushing is attached to the piston, combining the guidance function with the piston itself and eliminating the need for separate installation steps.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the master fitting is designed with a long cylinder axis to accommodate all components, then component functionality is ensured, but installation space increases

Engineering Contradiction:
Improvecomponent functionalityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The compensating chamber is positioned laterally adjacent to the cylinder rather than along the cylinder's longitudinal axis. This lateral arrangement utilizes space in a different dimension, reducing the overall length of the master fitting while maintaining all necessary functional components.

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

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 simplifies assembly, reduces installation space, and allows for adjustable reach, enhancing usability for users with small hands by ensuring reliable operation and maintaining hydraulic pressure without the need for additional components like trailing discs.

Implementation Method 1

a cylinder bore (140) is formed in a housing (107) and a piston (150) is guided in this cylinder bore (140), so that the free volume of the cylinder bore (140) can be increased or decreased depending on the position of the piston (150), so that the hydraulic fluid flows out of the cylinder or can be pressurized in the cylinder

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

When the piston moves, a seal attached to the piston moves over the connection opening to the compensation chamber, so that when the brake is actuated, the hydraulic system is closed and the pressure built up when the master fitting is actuated is not reduced via the compensation chamber

Methodology Applied
Scientific EffectSealing:

Implementation Method 3

changes in volume caused by temperature fluctuations can be compensated for, for example, due to the weather or during long braking processes

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3038893B1Master cylinder fitting
Publication Date: 2019.11.20 GUSTAV MAGENWIRTH GMBH & CO KG
  • EP3038893B1 patent drawingFigure 1~4
  • EP3038893B1 patent drawingFigure 2~3
  • EP3038893B1 patent drawingFigure 5~6

AI summary

The invention relates to a master cylinder fitting (100) for a hydraulic actuating element, having a housing (107) comprising an equalisation chamber (170) with an inner chamber (172) and a cylinder (140), the master cylinder fitting (100) also comprising a piston (150) guided in the cylinder (140). The cylinder (140) and the compensation chamber (170) are connected in at least one position of the piston via a connection channel (171), at least one overflow channel (173) being arranged at least at the mouth of the connection channel (171) in the cylinder wall.