Plunger-Cylinder Assembly Leadframe Sensor Integration

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Solution Overview

Problem

The existing piston-cylinder arrangements in motor vehicle clutch systems require complex assembly processes and numerous electrical interfaces due to the use of circuit boards for sensor systems, which are susceptible to environmental influences and occupy significant space.

Innovation Solution

The sensor system is integrated into a plastic housing using a leadframe arrangement, eliminating the need for a separate circuit board and reducing electrical interfaces by directly mounting electronic components on the leadframe, which provides mechanical stability and electrical contacting, and is sealed with a cover or casting compound to protect against vibrations and temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a circuit board is used to mount the sensor system, then the sensor system can be electrically connected and functionally operated, but the device complexity increases and the required space increases

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the circuit board functions directly into the housing structure by integrating contact elements into the plastic housing. The housing itself becomes part of the electrical connection system, eliminating the need for a separate circuit board and reducing overall device complexity while maintaining reliable electrical connections.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plastic housing is designed to serve multiple functions: it provides mechanical protection, structural support, and electrical connection pathways. By integrating contact elements and grounding structures into the housing, the component performs both mechanical and electrical functions simultaneously, reducing the number of separate components needed.

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

2Reliability

If a circuit board is used to mount the sensor system, then the sensor system can be electrically connected, but the number of electrical interfaces increases

Engineering Contradiction:
Improveelectrical contact reliabilityVSAvoidnumber of electrical interfaces
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple electrical connection functions are merged into the integrated housing structure. The contact elements, grounding paths, and signal transmission routes are all incorporated into the single housing component, reducing the number of separate electrical interfaces and connection points required.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If a separate sensor housing is used, then the sensor system is protected from environmental influences, but the required installation space increases

Engineering Contradiction:
Improveprotection from vibrations and temperatureVSAvoidinstallation space
Core Design Contradiction:
Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The sensor housing function is merged with the existing piston-cylinder housing. The same housing that contains the mechanical components also provides environmental protection for the sensor system, eliminating the need for a separate sensor housing and reducing overall installation space.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing is designed to serve dual purposes: mechanical containment of the piston-cylinder assembly and environmental protection of the sensor system. This multi-functional design reduces the total number of components and the space required for installation.

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

4Reliability

If additional mounting process steps are used to attach the circuit board, then the sensor system can be securely mounted, but the manufacturing time increases

Engineering Contradiction:
Improvemounting stabilityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The mounting function is merged into the injection molding process itself. Contact elements and electrical connection features are integrated directly into the housing structure during manufacturing, eliminating separate mounting steps and reducing assembly time while maintaining secure attachment.

Inventive Principle:
Principle #5Merging (Combining)

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 solution simplifies assembly, reduces space requirements, and enhances mechanical stability and environmental protection, resulting in a more integrated and efficient piston-cylinder arrangement with fewer parts and reduced production time.

Implementation Method 1

The linear displacement measuring system comprises a sensor system consisting of an inductive sensor unit with an electrically conductive target

Methodology Applied
Scientific EffectInductive sensing: Electromagnetic Induction

Implementation Method 2

Alternatively, a Hall sensor can be used as the sensor system, which includes a permanent magnet positioned on the piston

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3052828B1Plunger-cylinder assembly
Publication Date: 2020.11.11 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3052828B1 patent drawingFigure 1
  • EP3052828B1 patent drawingFigure 2~4
  • EP3052828B1 patent drawingFigure 5~6

AI summary

The invention relates to a plunger-cylinder assembly, in particular for a master cylinder of a clutch actuating system in a motor vehicle, having a plunger which is arranged axially movably in a cylinder which is configured as a housing, and having a sensor system which is arranged on the housing and is operatively connected to a sensor constituent part which is fastened to the plunger. In a plunger-cylinder assembly, in which the assembly is simplified by way of a reduction in the interfaces, the sensor system is positioned on a leadframe assembly which is integrated into the plastic housing.