Connecting Rod Calibration via Laser Induced Bending

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Solution Overview

Problem

Existing connecting rod arrangements in refrigerant compressors face challenges with angle errors due to lack of parallelism between the connecting rod eyes, leading to increased friction, wear, and potential leakages, which are difficult to address with current manufacturing methods without compromising tribological properties or increasing weight.

Innovation Solution

A method involving controlled energy input, such as laser irradiation, to create localized structural changes on the connecting rod, causing bending and precise adjustment of the connecting rod eye and crankshaft eye parallelism, eliminating the need for subsequent mechanical treatment and ensuring accurate alignment without altering the tribological properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If subsequent mechanical treatment is applied to achieve higher axis parallelism accuracy, then manufacturing precision is improved, but tribological properties (wear resistance) are compromised

Engineering Contradiction:

Improveaxis parallelismVSAvoidwear resistance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing laser-induced structural changes on the connecting rod surface before final assembly. The controlled energy input creates localized structural modifications that induce bending moments, adjusting the axis parallelism of the connecting rod eyes to within 2 μm over 20 mm. This preliminary calibration eliminates the need for subsequent mechanical treatment, preserving the tribological properties and wear resistance of the connecting rod surfaces.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If a rotating joint with bearing is added to equalize angle errors, then adaptability is improved, but device complexity and weight increase

Engineering Contradiction:

Improveangle error equalizationVSAvoidbearing structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the taking out principle by removing the complex bearing structure from the connecting rod arrangement. Instead of adding a rotating joint with bearing to equalize angle errors, the invention extracts the calibration function and integrates it directly into the connecting rod manufacturing process through laser-induced structural changes. This creates a simpler, more lightweight design that achieves the same angle error equalization without additional components.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical bearing system with a laser-based structural modification approach. By applying controlled energy input to create localized structural changes in the connecting rod, the system achieves angle error equalization through material property modification rather than mechanical adjustment. This substitution eliminates the need for complex rotating joints and bearings, reducing both device complexity and weight.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If a rotating joint with bearing is added to equalize angle errors, then adaptability is improved, but friction and play increase

Engineering Contradiction:

Improveangle error equalizationVSAvoidfriction and play

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This method achieves high accuracy in aligning the connecting rod eyes, reducing friction and wear, and enhancing the efficiency and lifespan of refrigerant compressors by ensuring precise angle alignment between the piston and crankshaft, while maintaining low weight and minimizing vibrations.

Implementation Method 1

the energy input occurs by at least one punctual irradiation, in particular with a laser

Methodology Applied

Scientific EffectLaser irradiation: Laser

Implementation Method 2

The energy input causes a relatively strong heating of a restricted surface area in the connecting rod

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 3

The subsequent cooling imposes a tension on the connecting rod that causes a concave bending of the connecting rod

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentUS8596187B2Method of calibrating a connecting rod arrangement and connecting rod arrangement

Publication Date: 2013.12.03 SECOP GMBH

AI summary

The invention relates to a method of calibrating a connecting rod arrangement comprising a crankshaft eye and a connecting rod eye. In order to achieve the best possible parallelism between the connecting rod eye and the crankshaft eye a controlled energy input occurs in at least one predefined surface area of the connecting rod, so that outside a neutral axis a local structural change and thus a tension in the connecting rod occurs.