Sensor Cleaning Piston with Rotation-Locked Spray Alignment

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Solution Overview

Problem

Existing cleaning devices for motor vehicles, particularly those used for optical and optoelectronic sensor devices, face challenges such as increased friction and wear due to dry contact surfaces, moisture penetration, and difficulty in maintaining precise alignment and rapid operational readiness, which are not adequately addressed by known designs with reciprocating pistons.

Innovation Solution

A cleaning device with a guide means to prevent the reciprocating piston from rotating, featuring a groove and projection design within the inner channel, a hydraulically sealed connecting piece, and a stepped bore with a sealing element for precise valve function, allowing for miniaturization and reduced component count, along with a collar for axial guidance and adjustable lifting height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the piston is guided using longitudinal ribs and grooves with dry contact, then the piston can be supported and guided during reciprocation, but friction and wear increase due to the enlarged dry contact surface

Engineering Contradiction:
Improvepiston guidance reliabilityVSAvoidfriction and wear
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces dry mechanical contact guidance with hydraulic guidance using a guide collar that creates a fluid film between the piston and housing. The guide collar has a smaller diameter than the piston, creating a hydraulic gap that reduces friction and wear while maintaining guidance functionality during piston reciprocation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Stability of the object's composition

If the guide collar has a larger diameter to provide better guidance, then guidance stability improves, but the gap length increases allowing more moisture and dirt penetration

Engineering Contradiction:
Improveguidance stabilityVSAvoidmoisture and dirt penetration
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The guide collar utilizes hydraulic pressure to maintain a stable fluid film gap that is sufficiently small to prevent moisture and dirt penetration while providing adequate guidance stability. The hydraulic pressure generated during piston operation maintains consistent gap spacing without requiring a large mechanical interference fit.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Manufacturing precision

If separate attachments are used for alignment, then alignment precision can be achieved, but device complexity and service effort increase

Engineering Contradiction:
Improvespray jet alignment precisionVSAvoidalignment mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent integrates the alignment function directly into the piston and spray nozzle assembly, eliminating the need for separate alignment attachments. The piston's cylindrical geometry and the spray nozzle's coaxial arrangement provide inherent alignment, reducing device complexity and service requirements while maintaining precise spray jet alignment.

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 design ensures exact and precise alignment of the spray jet, reduces service costs, and enhances reliability and adaptability, while maintaining aerodynamic and aesthetic requirements, with improved durability and reduced moisture ingress.

Implementation Method 1

a sealing element is provided to seal the mandrel against the bore in such a way that the inner channel is hydraulically impassable when the mandrel is immersed in the bore and hydraulically passable when the mandrel is withdrawn from the bore

Methodology Applied
Scientific EffectHydraulic sealing:

Implementation Method 2

The piston is extended from an unactuated, normally retracted, and therefore concealed starting position by hydraulic pressure of the cleaning fluid generated by a pumping device

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 3

After the pumping device is switched off, the piston is automatically returned to its starting position by spring force

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3887215B1Cleaning apparatus having a piston
Publication Date: 2024.09.04 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
  • EP3887215B1 patent drawingFigure 1a~1b
  • EP3887215B1 patent drawingFigure 2~3
  • EP3887215B1 patent drawingFigure 4a~4d

AI summary

The invention relates to a special cleaning apparatus (1), optimized for cleaning optical and optoelectronic sensor devices in motor vehicles, comprising a housing (2) and comprising a piston (3) which is movable in the housing (2) in a pressure-controlled manner and which can travel from a retracted starting position to an extended cleaning position along an actuating axis (A), wherein the piston (3) has an inner channel (4) for transporting a cleaning fluid through the piston (3) to a spray nozzle (5). The aim of the invention is to provide a cleaning apparatus (1) which is particularly miniaturized, simple and cost-effective to produce and which enables as exact and precise an alignment of the cleaning jet as possible, fast functional readiness, reduced tailing tendency of the cleaning fluid and improved adaptability to different installation positions. This aim is achieved, according to the invention, in that at least the cleaning apparatus (1) has at least one guide means (6) for rotation-locking the piston (3) about the actuating axis (A) during the entire stroke thereof, which guide means is arranged in the inner channel (4) at least in regions.