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Influence of variable surface coating on a force fitted interference fit assembly

Kallee, Richard (2006)
Product Development
Abstract
Interference fit assembly is a state-of-the-art technology for mounting cylindrical
shafts into bores. Due to its extreme cost-efficiency it is used even in high-tech
applications such as one of Bosch’s gasoline flow controllers. The picture below
shows the anchor-needle connection. Due to electromagnetic incitation the assembly
oscillates over 55 times per second. In order for the assembly to withstand the
occurring loads, hard materials are selected and high overlaps designed. As in other interference fit assemblies at Bosch, this aspiration for high retention
forces causes adhesion and galling. This type of cold welding process makes
assembly more difficult and retention capability absolutely indeterminable. Since the
design is... (More)
Interference fit assembly is a state-of-the-art technology for mounting cylindrical
shafts into bores. Due to its extreme cost-efficiency it is used even in high-tech
applications such as one of Bosch’s gasoline flow controllers. The picture below
shows the anchor-needle connection. Due to electromagnetic incitation the assembly
oscillates over 55 times per second. In order for the assembly to withstand the
occurring loads, hard materials are selected and high overlaps designed. As in other interference fit assemblies at Bosch, this aspiration for high retention
forces causes adhesion and galling. This type of cold welding process makes
assembly more difficult and retention capability absolutely indeterminable. Since the
design is optimized another way of adhesion avoidance is desired.
A survey was run on what could facilitate the process. The possibilities were broken
down to the following:
• Coatings (galvanic, chemical, PVD)
• Lubricants (waxes, oils, greases, fit-up aids, etc.)
• Glide lacquers (Klueber, Molykote)
• Glues (Loctite)
The target now was to create an overview of these 40 different alternatives in total
and their influence on interference fit assembly in general. Therefore the materials are
tested on inexpensive standardized parts – the dowel pin/bearing connection. The result will serve as a piece of reference for solution options in future interference fit
assemblies.
Current problems with the anchor-needle connection are too low retention forces and
occurrence of galling. The target values are consistent assembly forces below 4000N
and consistent retention forces above 1400N and adhesion avoidance. The general
survey results looking promising to solve this problem are reinvestigated on the
anchor-needle connection, in order to identify whether lubrication leads to the desired
results.
The ground-breaking discovery of a product actually designed as glue turns out to
solve the occurring problems. The deactivated glue perfectly meets the target values
and will pass through detailed analysis before being applied in serial production.
Therefore this research leads to a highly successful solution for the current problem.
Additionally a piece of reference is available for interference fit lubrication
potentialities. (Less)
Please use this url to cite or link to this publication:
author
Kallee, Richard
supervisor
organization
year
type
H2 - Master's Degree (Two Years)
subject
keywords
interference fit assembly, lubrication, coating technologies, glide lacquer, glue, adhesion, galling, process-safe statistical backup
language
English
id
1514847
date added to LUP
2009-12-07 15:29:25
date last changed
2010-02-01 14:40:06
@misc{1514847,
  abstract     = {Interference fit assembly is a state-of-the-art technology for mounting cylindrical
shafts into bores. Due to its extreme cost-efficiency it is used even in high-tech
applications such as one of Bosch’s gasoline flow controllers. The picture below
shows the anchor-needle connection. Due to electromagnetic incitation the assembly
oscillates over 55 times per second. In order for the assembly to withstand the
occurring loads, hard materials are selected and high overlaps designed. As in other interference fit assemblies at Bosch, this aspiration for high retention
forces causes adhesion and galling. This type of cold welding process makes
assembly more difficult and retention capability absolutely indeterminable. Since the
design is optimized another way of adhesion avoidance is desired.
A survey was run on what could facilitate the process. The possibilities were broken
down to the following:
• Coatings (galvanic, chemical, PVD)
• Lubricants (waxes, oils, greases, fit-up aids, etc.)
• Glide lacquers (Klueber, Molykote)
• Glues (Loctite)
The target now was to create an overview of these 40 different alternatives in total
and their influence on interference fit assembly in general. Therefore the materials are
tested on inexpensive standardized parts – the dowel pin/bearing connection. The result will serve as a piece of reference for solution options in future interference fit
assemblies.
Current problems with the anchor-needle connection are too low retention forces and
occurrence of galling. The target values are consistent assembly forces below 4000N
and consistent retention forces above 1400N and adhesion avoidance. The general
survey results looking promising to solve this problem are reinvestigated on the
anchor-needle connection, in order to identify whether lubrication leads to the desired
results.
The ground-breaking discovery of a product actually designed as glue turns out to
solve the occurring problems. The deactivated glue perfectly meets the target values
and will pass through detailed analysis before being applied in serial production.
Therefore this research leads to a highly successful solution for the current problem.
Additionally a piece of reference is available for interference fit lubrication
potentialities.},
  author       = {Kallee, Richard},
  keyword      = {interference fit assembly,lubrication,coating technologies,glide
lacquer,glue,adhesion,galling,process-safe statistical backup},
  language     = {eng},
  note         = {Student Paper},
  title        = {Influence of variable surface coating on a force fitted interference fit assembly},
  year         = {2006},
}