Segmented Camshaft Assembly for Lightweight Durability

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Solution Overview

Problem

Current camshaft manufacturing methods face challenges such as weight reduction, casting defects, and increased costs due to the need for separate joining processes, which affect durability and productivity.

Innovation Solution

A camshaft device comprising a main shaft, cam lobes, and journal bearings, where each component is fully assembled and manufactured using materials and methods suited to their characteristics, eliminating the need for a separate joining process and optimizing weight reduction and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum casting is used to insert iron-based lobe material into casting mold, then weight reduction is achieved, but casting defects occur and enduring toughness becomes insufficient

Engineering Contradiction:
Improvecamshaft weightVSAvoidenduring toughness
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The camshaft is divided into separate components: an aluminum shaft body and iron-based lobe components. These segments are manufactured separately using optimal materials for each function, then assembled together. This segmentation allows the aluminum shaft to provide weight reduction while the iron-based lobes provide durability, resolving the contradiction between weight and toughness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite construction by combining aluminum material for the shaft with iron-based material for the lobes. This composite approach leverages the lightweight properties of aluminum and the high strength/toughness of iron-based materials, achieving both weight reduction and sufficient enduring toughness that cannot be obtained with a single material.

Inventive Principle:
Principle #40Composite materials

2Reliability

If iron-based material is used for cam lobe and shaft, then durability is ensured, but weight reduction is limited

Engineering Contradiction:
ImprovedurabilityVSAvoidcamshaft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

Different parts of the camshaft are assigned different materials based on their specific functional requirements. The shaft body uses aluminum for weight reduction where strength requirements are moderate, while the lobes use iron-based material where high durability and wear resistance are critical. This local differentiation of material quality optimizes the overall performance by placing the right material in the right location.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If separate joining process is used to fix components, then component positioning is achieved, but production cost and time increase

Engineering Contradiction:
Improvecomponent positioning stabilityVSAvoidproduction efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The joining process is merged with the assembly process. Components are designed with integrated joining features that allow fixation to occur during the assembly operation itself, rather than requiring a separate subsequent joining step. This merging of operations eliminates redundant process steps, reducing both production time and cost while maintaining positioning stability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Joining features are preliminarily incorporated into the component designs during the design and manufacturing stages. The components are prepared with built-in positioning and joining mechanisms before assembly, so that when assembly occurs, the joining action is already facilitated and requires minimal additional steps. This preliminary preparation eliminates the need for complex separate joining processes.

Inventive Principle:
Principle #10Preliminary action

4Device complexity

If journal bearing is integrated into cam lobe, then component count is reduced, but load-bearing thickness becomes too thin

Engineering Contradiction:
Improvecomponent countVSAvoidload-bearing thickness
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The journal bearing is segmented from the cam lobe and becomes a separate assembly component. This segmentation allows the cam lobe to maintain its full load-bearing thickness for durability, while the journal bearing is provided separately with adequate dimensions for its rotational support function. The separation resolves the contradiction by allowing each component to be optimized independently for its specific function.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3441580B1Camshaft device and method for manufacturing camshaft device
Publication Date: 2021.02.17 KOREA AUTOMOTIVE TECH INST
  • EP3441580B1 patent drawingFigure 1
  • EP3441580B1 patent drawingFigure 2
  • EP3441580B1 patent drawingFigure 3

AI summary

The present invention relates to a camshaft device, which allows a plurality of components to be assembled to a main shaft, and a method for manufacturing the camshaft device. The camshaft device may include: a main shaft lengthily extending in the lengthwise direction; at least one cam lobe assembled to the main shaft and formed eccentrically from a rotation axis of the main shaft; at least one journal bearing assembled to the main shaft and formed to rotatably support the main shaft; and at least one guide shaft assembled to the main shaft and installed between the cam lobe and another cam lobe so as to align an assembling position of the cam lobe or the journal bearing.