Powder-Metal Locking Disc Geometry for Camshaft Adjuster

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Solution Overview

Problem

Existing camshaft adjusters face challenges in manufacturing due to geometry-related issues such as breakouts and density differences during powder-metallurgical production, leading to potential cracks and high reject rates, and require subsequent mechanical processing for calibration.

Innovation Solution

A variable camshaft adjuster with a locking disk made from powder-metal material featuring a locking bore with a radially extending oil channel, where the bottom of the locking bore has a raised shoulder and the oil channel depth is less than the locking bore, allowing for even pressing and reduced risk of cracks, and enabling calibration to achieve precise dimensional accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking bore with large cross-sectional differences and transitions is designed in conventional camshaft adjusters, then the oil channel can supply the locking bolt, but breakouts and significant density differences occur during powder-metallurgical production, leading to cracks and high reject rates

Engineering Contradiction:
Improveproduction reliabilityVSAvoidgeometry precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by designing the locking bore geometry in advance to prevent production defects. The locking bore is designed with a bottom that is at least twice as deep as the first surface, and the oil channel depth is limited to less than the locking bore depth. This preliminary geometric design ensures uniform pressing during green compact formation and prevents breakouts and density differences before production issues occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes critical geometric parameters of the locking bore and oil channel to resolve the contradiction. Specifically, the locking bore depth is set to be at least twice the depth from the first surface to the bottom, while the oil channel depth is constrained to be less than the locking bore depth. These parameter changes ensure uniform density distribution during powder metallurgy production while maintaining functional requirements.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional camshaft adjusters require subsequent mechanical processing for calibration, then dimensional accuracy can be improved, but production time and complexity increase

Engineering Contradiction:
Improvedimensional accuracyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies self-service by designing the locking bore and oil channel geometry to be self-calibrating during the powder metallurgy process. The specific geometric configuration (locking bore depth at least twice the surface depth, oil channel depth less than locking bore depth) enables the component to achieve precise dimensional accuracy inherently during production, eliminating the need for subsequent mechanical calibration operations.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3119997B1Variable camshaft adjuster with locking disc, locking disc, and method for producing same
Publication Date: 2020.03.11 GKN SINTER METALS ENG GMBH
  • EP3119997B1 patent drawingFigure 1~2
  • EP3119997B1 patent drawingFigure 3~4
  • EP3119997B1 patent drawingFigure 5

AI summary

The invention relates to a variable camshaft adjuster (VVT) for an internal combustion engine, comprising a VVT component (1), preferably a locking disc, made of a material made from powder metal, with a locking bore (2) which extends from a first surface (4) of the VVT component (1), preferably the locking disc, into the VVT component. A locking pin of a variable valve control means engages into the locking bore (2), and the locking bore has a connected oil channel (3) which likewise extends from the first surface (4) into the VVT component (1) and opens radially into the locking bore (2). A base (6) of the locking bore (6) has an elevation (7), preferably in the form of an elevated step, which is used as a bearing surface of the locking pin, and the oil channel has a depth which is shallower than that of the locking bore (2). The invention further relates to a VVT component, in particular a locking disc, and to a method for producing the locking disc or the camshaft adjuster.