Radial Cam Compressor Friction Reduction via Roller Follower

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Solution Overview

Problem

Existing compressor designs face inefficiencies due to space constraints and increased friction, particularly in multistage compressors operating at high pressures, where connecting rods limit piston travel and require continuous lubrication.

Innovation Solution

A radial cam-driven compressor with a central cam and cam follower assemblies using roller elements and guide brackets, which allow for radial piston arrangement and reduced friction through rolling contact, eliminating the need for continuous lubrication and optimizing space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a crankshaft and connecting rod assembly is used to convert rotary motion to linear motion, then reliability and operating efficiency are improved, but the space required by the connecting rod throughout complete rotation increases device complexity and limits piston travel in multistage compressors

Engineering Contradiction:
Improvecompressor reliabilityVSAvoidspace required by connecting rod
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the connecting rod from the traditional crankshaft mechanism, replacing it with a direct cam-follower-piston arrangement. The cam profile directly converts rotary motion to linear piston motion without requiring a separate connecting rod, thereby reducing the space required and simplifying the device while maintaining reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention transitions from the traditional planar crankshaft mechanism to a three-dimensional cam profile that achieves motion conversion through its geometric shape. The cam's radial and axial dimensions work together to provide the necessary motion transformation, eliminating the need for the connecting rod's spatial requirements

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If nutating heads are used to convert rotary motion into linear motion with piston travel parallel to the axis of rotation, then package space is reduced and connecting rod articulation is minimized, but sliding action increases friction and requires continuous lubrication

Engineering Contradiction:
Improvepackage spaceVSAvoidfriction from sliding action
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The invention employs a cam profile with curved surfaces that guide the follower through a controlled path. The cam's geometric curvature transforms the rotary motion into linear piston motion while maintaining rolling or reduced sliding contact, thereby reducing friction compared to traditional nutating head designs that rely entirely on sliding action

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the motion conversion mechanism from pure sliding action in nutating heads to a combination of cam profile geometry and follower contact. By adjusting the cam profile parameters (radius, curvature, pitch), the design optimizes the contact characteristics to reduce friction while maintaining the compact package space advantage

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If piston travel is limited to under 1.27 cm in higher-stage pistons to accommodate connecting rods, then device complexity is reduced, but compressor efficiency decreases

Engineering Contradiction:
Improvepiston assembly simplicityVSAvoidcompressor efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

By removing the connecting rod constraint, the invention enables higher-stage pistons to achieve greater travel distances. The direct cam-follower connection allows piston travel to exceed 1.27 cm without increasing device complexity, as the cam profile itself provides the motion conversion function previously requiring a connecting rod

Inventive Principle:
Principle #2Taking out (Extraction)

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

The radial cam-driven compressor design enhances efficiency by reducing friction, eliminating the need for continuous lubrication, and accommodating higher piston travel, thereby improving overall compressor performance and reducing component complexity.

Implementation Method 1

a roller element rotatably connected to a roller bracket... the roller element of each of said cam follower assemblies being in rolling contact with said cam

Methodology Applied
Scientific EffectRolling contact: Roller

Data Source

PatentEP2232068B1Radial cam-driven compressor and cam-driven compressor assemblies
Publication Date: 2017.11.08 MISSION SYSTEMS DAVENPORT INC
  • EP2232068B1 patent drawingFigure 1
  • EP2232068B1 patent drawingFigure 2
  • EP2232068B1 patent drawingFigure 3

AI summary

A first aspect of the invention includes a multi-stage gas compressor having a central cam with a plurality of pistons operably connected to and radially extending from the central cam. The cam follower assemblies each include a roller element connected to a roller bracket which rides within and along a guide channel defines by facing grooves formed in housing end plates.