Piston-Cylinder Sensor Sealing for Leak-Free Removal

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Solution Overview

Problem

Existing piston-cylinder units face challenges in assembly and disassembly efforts, component variety, and stress on piston movement sensors due to high fluidic pressures and the need for precise positioning and alignment, which complicates the integration and removal of the sensor housing without leaking hydraulic fluid.

Innovation Solution

The piston movement sensor is fluidically separated from the pressure chamber using a sealing element, and a positioning and alignment element ensures accurate placement and orientation within the transverse bore, allowing for secure attachment and easy removal while maintaining the seal, utilizing a dielectric lens or collimator for signal alignment and focusing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the piston motion sensor is integrated in the cylinder head with fluidic separation, then the assembly and disassembly effort is reduced and the sensor housing stress is reduced, but the fluidic sealing complexity increases

Engineering Contradiction:
Improveassembly and disassembly effortVSAvoidfluidic sealing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The cylinder head is segmented into a sensor region and a hydraulic fluid region by the sealing element. The sealing element creates a fluidic barrier that separates the transverse bore (sensor housing area) from the pressure chamber, allowing independent assembly and disassembly of the sensor while maintaining hydraulic sealing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element acts as an intermediary component between the sensor housing and the hydraulic fluid system. It provides the necessary fluidic separation while allowing the sensor to function independently, reducing the complexity of integrating sensors into high-pressure hydraulic environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the piston motion sensor is positioned in the transverse bore, then the measurement accuracy is improved, but the positioning and alignment precision requirements increase

Engineering Contradiction:
Improvepiston position measurement accuracyVSAvoidsensor positioning and alignment precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The transverse bore is pre-formed in the cylinder head with precise geometry and positioning. This preliminary structural preparation ensures that when the sensor housing is installed, it automatically achieves the correct alignment and position for accurate piston measurement, reducing the need for post-installation adjustment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transverse bore serves multiple functions: it provides structural support, defines the sensor positioning, establishes alignment references, and maintains fluidic separation. This multi-functionality reduces the number of separate components needed and simplifies the overall positioning system.

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

3Ease of repair

If the sensor housing is made removable, then the ease of repair and maintenance is improved, but the risk of hydraulic fluid leakage increases

Engineering Contradiction:
Improvesensor housing removabilityVSAvoidhydraulic fluid sealing reliability
Core Design Contradiction:
Ease of repairVSReliability

Solution Approach 1:

The sealing system is segmented into distinct sealing interfaces: one between the sealing element and the cylinder head, and another between the sealing element and the sensor housing. This segmentation allows the sensor housing to be removable while maintaining reliable sealing at each interface through dedicated sealing elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element is designed with inherent sealing capacity and tolerance compensation features that cushion against misalignment and wear. This beforehand cushioning ensures that even with repeated assembly and disassembly, the hydraulic fluid sealing remains reliable without requiring perfect precision each time.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 enhances the assembly and disassembly efficiency, reduces stress on the sensor housing, and ensures precise measurement accuracy by maintaining the hydraulic seal and allowing for the use of a single sensor across different piston-cylinder unit dimensions with minimal signal attenuation.

Implementation Method 1

utilizing a dielectric lens or collimator for signal alignment and focusing

Methodology Applied
Scientific EffectDielectric lens focusing: Lens

Implementation Method 2

utilizing a dielectric lens or collimator for signal alignment and focusing

Methodology Applied
Scientific EffectCollimation:

Implementation Method 3

The piston movement sensor is fluidically separated from the pressure chamber using a sealing element

Methodology Applied
Scientific EffectSealing:

Implementation Method 4

The piston motion sensor emits a sensor signal. This signal travels from the piston motion sensor through the pressure chamber to the piston or a piston rod. The sensor signal is reflected by the piston or piston rod.

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Data Source

PatentEP4246002B1Piston-cylinder unit
Publication Date: 2024.02.21 PACOMA GMBH
  • EP4246002B1 patent drawingFigure 1
  • EP4246002B1 patent drawingFigure 2
  • EP4246002B1 patent drawingFigure 3

AI summary

The invention relates to a piston-cylinder unit (1). A piston motion sensor (28) is arranged in a transverse bore (27) of a cylinder head (4) of the piston-cylinder unit (1). According to the invention, the transverse bore (27) is separated from a pressure chamber (33) that acts on a piston (7) of the piston-cylinder unit (1). This separation can be achieved by sealing a collimator (35) arranged in the beam path of a sensor signal against a sensor signal channel (26) via a sealing element (37). The seal allows the housing of the piston motion sensor (28) to be removed from the transverse bore (27) without the fluid from the pressure chamber (33) escaping into the environment. The piston-cylinder unit (1) according to the invention is used, for example, in a work machine, construction machine, agricultural machine, maritime machine, wheel loader, excavator, tipper truck, crane, forklift truck or lifting platform.