Camshaft Phaser Sealing via Integral Actuator Bonding

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Solution Overview

Problem

Existing camshaft adjuster kits driven by belts face challenges in ensuring reliable sealing while being cost-effective and easy to produce, particularly when using dry-running traction drives.

Innovation Solution

A kit with a central valve and actuator, where the pressure fluid distribution space is sealed through material and non-positive connections, eliminating the need for separate sealing elements, and utilizing a plasma-nitrided, thin sleeve and plastic centering ribs for robust and efficient assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate sealing elements are used to seal the pressure fluid distribution space, then sealing reliability is improved, but device complexity and production costs increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The actuator components (armature, pole core, pole tube) are directly integrated with the central valve to form a unified sealing structure. The armature is welded to the central valve, and the pole core is press-fitted into the pole tube, eliminating the need for separate sealing elements while maintaining sealing reliability through the material connections themselves.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator components serve dual functions: they provide actuation functionality and simultaneously create the sealing structure through their material connections to the central valve. The sleeve with plasma nitriding coating and the plastic centering ribs enable the components to self-seal without requiring additional sealing elements.

Inventive Principle:
Principle #25Self-service

2Duration of action of stationary object

If a thick sleeve is used without coating to ensure durability, then service life is improved, but installation space and weight increase

Engineering Contradiction:
Improvesleeve service lifeVSAvoidsleeve volume
Core Design Contradiction:
Duration of action of stationary objectVSVolume of moving object

Solution Approach 1:

The sleeve undergoes plasma nitriding, a surface treatment process that fundamentally changes the parameters of the surface layer. This creates a hard, wear-resistant coating with enhanced durability while maintaining the thin-wall construction, allowing the sleeve to achieve long service life without increasing thickness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The sleeve combines base metal material with a plasma-nitrided surface layer, creating a composite structure. The thin-walled base material provides the structural form, while the nitrided surface layer provides the wear resistance and durability, achieving both compact dimensions and long service life.

Inventive Principle:
Principle #40Composite materials

3Manufacturing precision

If precise centering mechanisms are implemented to compensate for assembly tolerances, then assembly precision is improved, but device complexity and installation space increase

Engineering Contradiction:
Improveassembly centering precisionVSAvoidcentering mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Complex mechanical centering mechanisms are replaced with simple plastic injection-molded centering ribs. These ribs provide effective centering through their geometric shape and material properties, compensating for assembly tolerances without requiring complex mechanical adjustment systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The plastic centering ribs act as flexible, formable elements that can accommodate minor dimensional variations. The plastic material allows the ribs to be injection-molded directly onto the coil body, providing tolerance compensation through the molding process itself rather than requiring adjustable mechanical components.

Inventive Principle:
Principle #30Flexible shells and thin films

4Manufacturing precision

If backlash compensation mechanisms are added to account for coaxial errors, then positioning accuracy is improved, but device complexity and stroke requirements increase

Engineering Contradiction:
Improvecoaxial positioning accuracyVSAvoidactuator stroke requirements
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

Coaxial alignment is achieved through preliminary centering actions during assembly using the plastic centering ribs. These ribs ensure that the actuator components are pre-aligned coaxially before final assembly, eliminating the need for runtime backlash compensation and reducing the required actuator stroke.

Inventive Principle:
Principle #10Preliminary action

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

Ensures reliable sealing and operational reliability of the belt drive area, reducing production complexity and costs, while maintaining long service life and minimizing installation space.

Implementation Method 1

the sleeve is provided as a thin, non-cutting sleeve and has a coating produced by plasma nitriding

Methodology Applied
Scientific EffectPlasma nitriding: Nitriding

Implementation Method 2

the actuator comprises at least one armature that can be moved by means of a coil, a pole core and a pole tube as a pole tube assembly

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3688288B1Assembly comprising a camshaft phasing device
Publication Date: 2021.08.11 ECO HLDG 1 GMBH
  • EP3688288B1 patent drawingFigure 1
  • EP3688288B1 patent drawingFigure 2
  • EP3688288B1 patent drawingFigure 3

AI summary

The invention relates to a kit (1), comprising a camshaft phaser (2), in which a central valve (3) is provided, which distributes a pressure fluid, and comprising an actuator (4), which controls the central valve (3). The camshaft phaser (2) is or can be driven by means of a dry-running traction mechanism drive and has a rotor (6) rotatably mounted in a stator (5). A pressure fluid distribution chamber (7) is provided between the camshaft phaser (2) and the actuator (4), which pressure fluid distribution chamber can be filled with pressure fluid via the central valve (3) and is connected to an armature chamber (8) of the actuator (4) and is sealed off from the environment. The actuator (4) comprises at least one armature (16) movable by means of a coil (18), one pole core (27) and one pole tube (28) as a pole tube assembly (17). According to the invention, the pressure fluid distribution chamber (7) is sealed by means of an integral bond and/or frictional and interlocking connection of the actuator or of one or more actuator components to the central valve.