Tube Bending Mandrel Lubrication Through Articulated Elements

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Solution Overview

Problem

Existing mandrel assemblies in tube bending machines fail to provide sufficient lubrication, leading to overheating, malfunctioning, and potential tube rupture, necessitating manual pre-lubrication in demanding applications.

Innovation Solution

A mandrel assembly with articulation elements featuring through-holes and a deflector element to distribute lubricant effectively across the tube interior, eliminating the need for manual pre-lubrication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If lubricant is supplied through the mandrel rod and distributed by outlet ports on the mandrel body, then the lubrication system is simple, but the lubrication distribution is insufficient in demanding applications

Engineering Contradiction:
Improvelubrication system complexityVSAvoidlubrication sufficiency
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The lubrication system is segmented into multiple distribution paths: the mandrel body outlets and the articulation element through-holes. This segmentation allows lubricant to reach multiple locations simultaneously, improving distribution coverage without requiring a complex multi-pump system. The articulation elements act as independent distribution segments that deliver lubricant to specific high-friction zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The articulation elements serve as intermediary components that receive lubricant from the mandrel body and redistribute it to the spaces between successive articulation elements. This intermediary function ensures that lubricant reaches areas that would otherwise be difficult to access, improving overall lubrication effectiveness without directly modifying the main supply system.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If manual pre-lubrication is performed by the operator, then lubrication is sufficient, but the process requires additional manual intervention and time

Engineering Contradiction:
Improvelubrication adequacyVSAvoidmanual intervention requirement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The mandrel assembly performs self-lubrication through its articulated structure. The articulation elements with through-holes automatically distribute lubricant to the spaces between them during the bending operation, eliminating the need for manual pre-lubrication. The system uses its own motion and structure to deliver lubricant where needed, making the process self-sufficient.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The lubricant distribution channels in the articulation elements are pre-configured to deliver lubricant to critical areas before the bending operation begins. The through-holes are positioned to ensure lubricant reaches the spaces between articulation elements in advance, preparing the interface for optimal lubrication during the bending process.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If poor lubrication occurs, then the process may be more economical without additional systems, but overheating and tube rupture risks increase

Engineering Contradiction:
Improveprocess economyVSAvoidoverheating and rupture risk
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses multiple lubricant distribution points (mandrel body outlets plus articulation element through-holes) to provide excessive lubrication coverage in critical areas. This partial over-lubrication ensures that even under high-friction conditions, sufficient lubricant is present to prevent overheating and rupture, while the articulated structure directs this excess lubricant precisely where needed.

Inventive Principle:
Principle #16Partial or excessive action

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

Enhances lubrication distribution, ensuring consistent lubrication, preventing overheating, and reducing the risk of tube rupture, while making the process more reliable, repeatable, and economical.

Implementation Method 1

a network of lubricant transport channels formed through the mandrel body and communicating with a lubricant feed passage formed along the mandrel rod

Methodology Applied
Scientific EffectFluid flow through channels:

Implementation Method 2

said deflector element being configured to radially deflect outwardly the lubricant exiting the through-holes

Methodology Applied
Scientific EffectFluid deflection:

Implementation Method 3

A fundamental aspect is the formation of a substantial lubricant film in the gap between the mandrel assembly and the inner surface of the tube

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4631638A1Mandrel assembly for a tube bending machine
Publication Date: 2025.10.15 BLM
  • EP4631638A1 patent drawingFigure 1~2
  • EP4631638A1 patent drawingFigure 3~4
  • EP4631638A1 patent drawing

AI summary

A mandrel assembly for a tube bending machine, comprising a mandrel body (21), a mandrel rod (23), a series of articulation elements (24-26) connected to one another and to the mandrel body (21) through respective cylindrical or spherical hinges (27-28), and a network of lubricant transport channels (31-36) formed through the mandrel body (21) and communicating with a lubricant feed passage (23a) formed along the mandrel rod (23). The network of lubricant transport channels (31-36) comprises a plurality of lubricant outlet ports (34, 36) arranged on the distal end (21b) or on a peripheral surface (21c) of the mandrel body (21). A plurality of through-holes (37) extending along the longitudinal direction of the respective articulation element (24-26) is formed through each of the articulation elements (24-26). The through-holes (37) are configured to convey a lubricant to the front side of an extreme distal articulation element (26) of the series of articulation elements (24-26). The extreme distal articulation element (26) comprises a deflector element (38).