Piston Cam Engine 3D Cam Segmentation for Vibration Reduction

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Solution Overview

Problem

Existing piston cam engines face challenges with balance, noise, vibrations, and high manufacturing costs due to rigidly connected pistons and complex cam groove precision requirements, which lead to micro strokes and increased production complexity.

Innovation Solution

A piston cam engine design featuring a cylindrical tubular 3D cam with corrugated sections and spacers to form a constant cross-section cam groove, along with guide columns and followers with adjustable arms and rollers to ensure balanced motion and reduce micro impacts, allowing for flexible manufacturing and reduced vibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If guide groove is used for linear guidance of followers, then precise guidance of pistons is ensured, but micro strokes occur between contact surfaces of rollers and groove when piston motion direction changes

Engineering Contradiction:
Improveguidance precisionVSAvoidmicro strokes
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The single guide groove is segmented into multiple guide grooves (first guide groove and second guide groove) that are spatially separated and oriented at different angles. This segmentation allows the follower to be guided by multiple independent grooves simultaneously, eliminating the micro strokes that occur in single-groove designs when motion direction changes.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If cylinders and pistons are manufactured with high precision, then precise guidance of pistons is ensured, but manufacturing costs increase

Engineering Contradiction:
Improvepiston guidance precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The guidance function is extracted from the piston-cylinder interface and transferred to the separate guide grooves formed in the cam structure. This allows the pistons and cylinders to be manufactured with lower precision while the guidance accuracy is provided by the precisely formed guide grooves, reducing overall manufacturing costs.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The guide grooves act as intermediary elements between the pistons and the cam groove. Instead of requiring direct high-precision配合 between pistons and cylinders, the guide grooves mediate the motion, allowing lower precision components to work together effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If 3D cam is made monolithic, then structure is simplified, but it is difficult to produce the internal cam groove with high precision

Engineering Contradiction:
Improvecam structure complexityVSAvoidcam groove precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The monolithic 3D cam is segmented into multiple separate components (first cam and second cam) that are assembled together. This segmentation makes it feasible to manufacture each cam with precise guide grooves using conventional machining methods, while the assembled structure maintains the required guidance precision.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If pistons are rigidly connected, then construction is simplified, but balance inertial force cannot be created

Engineering Contradiction:
Improvepiston connection complexityVSAvoidbalance inertial force
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The rigid connection between pistons is replaced with a dynamic connection through the follower mechanism. The follower allows the pistons to move independently while maintaining coordinated motion through the cam groove, enabling the creation of balanced inertial forces while preserving mechanical connection.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1937938B1Piston cam engine
Publication Date: 2011.03.23 BAHNEV BOYAN K
  • EP1937938B1 patent drawingFigure 1
  • EP1937938B1 patent drawingFigure 2a~2c
  • EP1937938B1 patent drawingFigure 3a~3d

AI summary

The invention relates to a piston cam engine used in different fleld of the mechanical engineering, as internal-combustion engines compressors, pumps etc. The cam engine comprises cylinders (13) with pistons (20), a cylindrical tubular 3D cam (3) having a cam groove on the inner cylindrical surface and at least two guides (10) which are guide columns. The cam (3) is composed and includes two coaxial bushes (3a, 3b), each one having corrugated cam section (95a or 95b) from its one side and flange (35) from its other side besides the bushes (3a, 3b) are positioned against each other with its corrugated ends at a distance from each other, and further comprises spacer (37) between the flanges (35) of the bushes (3a, 3b), so as to form the cam groove having a constant section.