Variable Valve Device Camshaft Alignment

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Solution Overview

Problem

Existing variable valve lift devices for engines face challenges in achieving accurate assembly and stable operation due to machining errors, leading to reduced engine performance and durability.

Innovation Solution

A variable valve device with a camshaft and a movable cam device featuring shaft grooves and cam grooves with specific cross-sectional shapes, along with an insertion member, allows for precise alignment and rotational force transmission without serration or spline structures, enhancing concentric axis alignment and reducing rigidity degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional variable valve lift devices use traditional coupling structures (serration or spline), then rotational force can be transmitted, but machining errors lead to poor concentric axis alignment and reduced assembly accuracy

Engineering Contradiction:

Improveconcentric axis alignmentVSAvoidcoupling structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent removes the complex serration or spline coupling structures from the camshaft and movable cam device. Instead, it uses a simple insertion member that fits into a through-hole, extracting the unnecessary complexity while maintaining rotational force transmission functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Rather than using external coupling structures (serration/spline) to transmit rotational force, the patent inverts the approach by using an internal through-hole structure with a simple insertion member. This inverted design simplifies the coupling mechanism while improving alignment accuracy.

Inventive Principle:

Principle #13The other way round (Inversion)

2Strength

If traditional coupling structures are used, then rotational force transmission is achieved, but rigidity degradation occurs due to machining errors

Engineering Contradiction:

ImproverigidityVSAvoidassembly accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent extracts the problematic serration or spline structures that cause rigidity degradation. By removing these complex coupling structures and replacing them with a simple through-hole insertion design, the patent eliminates the source of rigidity loss while maintaining functional requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a composite structural approach by combining the camshaft, movable cam device, and insertion member into an integrated assembly. This composite structure improves overall rigidity and reduces the negative effects of machining errors through the simplified coupling design.

Inventive Principle:

Principle #40Composite materials

3Reliability

If conventional variable valve lift devices operate, then engine control is performed, but operational stability is reduced due to assembly inaccuracies

Engineering Contradiction:

Improveoperational stabilityVSAvoidassembly accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent removes the sources of assembly inaccuracies by eliminating complex coupling structures. The simplified through-hole insertion design reduces accumulation of machining errors, thereby improving operational stability and reliability of the variable valve lift device.

Inventive Principle:

Principle #2Taking out (Extraction)

4Duration of action of stationary object

If complex coupling structures are used for rotational force transmission, then functionality is maintained, but durability of the camshaft is reduced

Engineering Contradiction:

Improvecamshaft durabilityVSAvoidcoupling structure

Core Design Contradiction:

Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts the complex coupling structures (serration or spline) that reduce camshaft durability. By replacing them with a simple through-hole insertion member design, the patent reduces stress concentration and potential failure points, thereby extending camshaft service life.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS10458294B2Variable valve device for engine

Publication Date: 2019.10.29 HYUNDAI MOTOR CO LTD

AI summary

A variable valve device for an engine, may include a camshaft; a movable cam device fitted over the camshaft to be slidable in an axial direction of the camshaft, and configured such that cams with at least two different cam profiles and a guide protruding portion are disposed along the axial direction of the camshaft; at least one shaft groove linearly processed to have a predetermined cross-sectional shape in an external circumferential surface of the camshaft along the axial direction thereof; a cam groove provided in an internal circumferential surface of the movable cam device to communicate with the shaft groove; and an insertion member inserted into a communication space defined by the shaft groove and the cam groove such that a rotational displacement of the camshaft is transmitted to the movable cam device.