science滚齿机类型的毕业设计翻译

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滚齿机类型的毕业设计翻译evelopment of a new rapid characterization method of hobs wear resistance in
gear manufacturing-Application to the evaluation of various cutting edge
preparations in high speed dry gear hobbing
C. Claudin， J. Rech∗
Université de Lyon， Ecole Nationale dIngénieurs de Saint-Etienne， LTDS， CNRS UMR5513， 58 Rue Jean Parot， 42000 Saint-Etienne， France
article info
Article history:
Received 31 December 2008
Received in revised form 22 February 2009
Accepted 23 February 2009
Keywords:
Gear hobbing
Dry cutting
Cutting edge preparation
High speed steel
Abrasive flow machining
Micro-sandblasting
abstract
Gear hobbing remains a cutting technology mainly dedicated to large-scale productions of gears for the
automotive industry. The improvements in hobbing tool design are problematic due to the very long
duration of wear tests and due to the application of special machine tools only available in production
plants. In order to overcome these limitations and to accelerate the efficiency of the investigations， a
new rapid testing method called flute hobbing” has been developed on a standard five-axes milling
machinewidely present in research laboratories. This testingmethod has been associatedwith a software
providing the geometry of each chip in hobbing. The correlation of the chip geometry with the wear of
each tooth enables to discriminate the critical teeth of a hob in order to focus the development in this
area of the cutting zone. This new methodology has been used to investigate the influence of the cutting
edge preparation on the wear resistance of gear hobs made of PM-HSS in the context of dry high speed
manufacturing. The application of the AFM technology to generate defined edge preparation has shown
its efficiency to improve the tool wear resistance and has confirmed previous results.
© 2009 Elsevier B.V. All rights reserved.
1. Introduction
Among the gears produced in the world， 80% of them are desti-
nated to a car (Rech， 2002).Among themanufacturing technologies，
gear hobbing remains the leading cutting technology especially for
the roughing step. Considering the 60 millions of cars produced
each year in the world and considering that an average number of
15 gears are hobbed， this technology produces over 900millions of
gears per year， which represents a huge activity， but distributed
between a small numbers of actors. Standard cutting processes，
such as milling， turning， have taken benefit from a lot of inno-
vations over the 20 past years. These innovations were based on
new substrates and new coatings for cutting tools， new high speed
machines， new lubrication system， etc. On the contrary， gear hob-
bing faces a lot of problems to integrate these innovations. The
improvements in hob design are problematic due to the very long
duration of wear tests (several weeks)， due to the expensive cost
of gear hobbing machines (>400kD )， due to the expensive cost of
hobs (>1000D )， and due to the long delay of delivery (>2 months).
Moreover， hobbingmachines are usually only present in production
plants， which does not facilitate to conduct investigations.
∗ Corresponding author. Tel.: 33 677098123; fax: 33 477438499.
E-mail address: joel.rech###enise.fr (J. Rech).
Several years ago， the WZL laboratory by the TU Aachen (Ger-
many) has developed an original hobbing test on a hobbing
machine， so-called fly hobbing. One of the publications present-
ing this procedure has been presented by Bouzakis et al. (2002a).
This process is based on the same kinematic as a hobbing opera-
tion， but involves a single tooth (Fig. 1). Considering that a hob has
a very large number of teeth， each tooth (each generating position)
removes a specific chip (i.e. specific undeformed chip geometry).
So the wear induced on each tooth is different from their neigh-
bours. On the contrary， in fly hobbing， this single tooth cumulates
thewear supported by all the teeth of a hob， since the fly tooth takes
the place of each tooth one after the other (Fig. 1). This small tool
enables an easier observation of thewearmodes obtained after the
complete simulation of a hob bymeans of a SEM， on the contrary to
a standard hob having typically a diameter of 100mmand a length
of 200mm. This fly hobbing is very efficient to obtain industrial
results about the wear resistance of a new hob design. However， it
cannot provide informations about the most damaging zone in the
contact zone. Indeed a large number of teeth are involved in this
zone. They allhave adifferent volume ofworkmaterial to remove.As
shown in Fig. 1， two zones are commonly distinguished: a so-called
roughing zone supporting large chip sections and a finishing zone
supporting thin chip sections. The industrial practice of gear hob-
bing indicates that roughing teeth are the most critical teeth in
high speed steel (HSS) gear hobbing， whereas using carbide hobs
can contradict this statement. In deed， there are