Note: Descriptions are shown in the official language in which they were submitted.
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WORKING METHOD AND DEVICE FOR SMOOTHING GEARWHEELS
The present invention relates to a method and a device for
smoothing gearwheels.
A gearwheel polishing and honing machine is known from
DE 3230860 C2, which has a similar basic construction as
the present invention for smoothing gearwheels, the
gearwheels to be smoothed and the smoothing wheels used
being washed with a large quantity of a coolant-lubricant
emulsion in order to reduce the production of frictional
heat and remove the abraded material.
The use of such a coolant-lubricant emulsion particularly
has the disadvantage that the entire device must be sealed
on all sides in order to prevent escape of liquid or
sprayed water and the emulsion must be kept in a loop and
continuously treated, and the abraded material must be
removed and/or filtered out of the emulsion in particular.
This treatment is very complex and the filters used must be
disposed of and kept new, which generates very high
operating costs, maintenance costs, and unnecessarily great
environmental strain overall. Furthermore, the shaft
bearings used on the smoothing wheels must be provided with
a central lubrication so they are not destroyed over long
periods by the coolant and lubricant, which are sometimes
aggressive. Even if the gearwheels to be smoothed and the
smoothing wheels are only washed with low-viscosity oil,
the requirement for treating washing oil is maintained.
The object of the present invention is to provide a working
method and a device for smoothing gearwheels, which may be
operated significantly more cost-effectively and in a more
environmentally friendly way and/or which allow a
significantly simpler method sequence and device
construction.
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This object is achieved according to the present invention
in connection with the features of the preambles of Claims
1 and 9 in combination with the characterizing features of
the claims cited.
Because the device for smoothing gearwheels, which is
equipped with at least one smoothing wheel that acts
radially on a gearwheel to be smoothed and therefore may be
engaged and disengaged, is provided with a spray nozzle,
using which a fine lubricant spray mist, particularly made
of oil, is sprayable on the gearwheels, it becomes possible
to dispense completely with the use of a coolant-lubricant
emulsion. In this way, the construction outlay for the
device is significantly reduced, since, for example, water-
tight boxes which enclose the device must no longer be
positioned around the device and central lubrication of the
bearings, which may now be replaced by typical permanently-
sealed bearings, may be dispensed with completely.
Furthermore, the cleaning of the device is significantly
simplified, since it is not always completely wetted by the
coolant-lubricant emulsion. Post-processing such as drying
of the workpieces is also completely dispensed with.
Further advantageous embodiments of the object of the
present invention result from and in combination with the
following method and device claims.
Because, in an especially advantageous embodiment of the
device, the spray nozzle is pointed directly at the
gearwheel to be smoothed, it becomes possible to ensure
sufficient lubrication during the smoothing process using
an extremely small quantity of sprayed oil, without the
smoothing wheels or the gearwheel to be smoothed being
negatively influenced hereby. Since the device is purely a
smoothing device for gearwheels, in which, for example,
scale residues from the heat treatment of the gearwheels
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are removed, hardly any noticeable material abrasion is to
be expected, so that the use of washing oil or other
cleaning liquid may be dispensed with completely.
The lubricant is preferably sprayed on a free surface
region of the gearwheel to be smoothed when the already
rotating smoothing wheel has been engaged load-free with
the gearwheel to be smoothed, this advantageously occurring
during a complete rotation of the gearwheel to be smoothed,
through which complete and sufficient lubrication of the
entire operating region of the gearwheel is ensured before
beginning the basic operating step by applying the high
pressure force. Method sequences in which the lubricant is
sprayed one or more times shortly before and/or at the
beginning of and/or even during the smoothing process are
also conceivable.
According to a further preferred embodiment of the object
of the present invention, the smoothing machine is equipped
with a device, which generates an air stream, and
corresponding air distribution lines to the gearwheel to be
smoothed, but particularly only to the smoothing wheels, so
that their heating because of frictional heat may be
counteracted in a very simple and cost-effective way.
Furthermore, the gearwheels to be smoothed, which are
continuously replaced, contribute to cooling of the
smoothing wheels, which are always fixed on the device. In
principle, other gases may also be used here.
An embodiment of the device in which the device that
generates the air stream is provided with an assembly that
operates according to the Joule-Thompson affect and also
has a narrow expansion nozzle, in which the highly
compressed air cools down strongly as it passes, values
below -30 C to -50 C being achieved here, is especially
advantageous. Using such an assembly, the occurrence of
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frictional heat is counteracted in a technically simple but
effective way, which also operates quasi-wear-free.
The working method which may be performed using the device
essentially corresponds to the known methods for smoothing
gearwheels, their typical lubrication and cooling using a
coolant-lubrication emulsion or using pure washing oils
being replaced by an extremely minimal quantity of
lubrication using a lubricant such as oil. This oil is
sprayed one time at the beginning or during, but
particularly before the beginning of the smoothing process,
advantageously directly by one single spray nozzle as a
fine spray mist onto the gearwheel to be smoothed, this
sprayed oil quantity being sufficiently low that even after
multiple hours of operation of the device, no oil sprays or
larger contaminations are to be found in the region below
the smoothing wheels. The application of the lubricant is
preferably performed when the rotating smoothing wheel has
been engaged load-free with the gearwheel to be smoothed,
particularly using a spray stream lasting long enough that
the gearwheel may be wetted over its entire circumference
and all tooth flanks with lubricant.
The working method is also extremely environmentally
friendly, since the quantities of oil used are very low and
no liquids to be recycled arise. Furthermore, the entire
device is very well accessible at any time, even in
operation, and the operating process is observable, since
the device is not permanently quasi-"underwater" and the
view is not obstructed by sprayed spray protection walls.
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In one broad aspect, there is provided a method
for burnishing gearwheels in a corresponding device having
at least one burnishing wheel, the burnishing wheel acting
radially on a gearwheel to be burnished, in which the
burnishing wheel is driven via a motor and the gearwheel to
be burnished is kept pressed with a high pressure force and
along its axis of rotation oscillating against the
burnishing wheel during a main operating step, wherein a
minimal quantity of lubricant is applied to at least one of
the gearwheel to be burnished and to the burnishing wheel,
and that the lubricant is sprayed onto a free surface region
of the gearwheel to be burnished.
In the following, an exemplary embodiment of the
present invention is described in greater detail on the
basis of the drawing.
Figure 1 shows an overall spatial illustration of
a device for smoothing gearwheels and
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Figure 2 shows a detail enlargement of the operating
region.
The device for smoothing or burnishing gear-wheels includes a machine
table 10, on which two parallel guide rails 11 are placed,
on which a frame-shaped carriage 12 for a driving smoothing
wheel 5 and a further carriage 13, inside, the carriage 12,
for a driven pair of smoothing wheels 29 is positioned so it
is movable,-a pressurecylinder 14 being positioned on the
carriage 12 for the driving smoothing wheel 5, which presses
the carriage 13 for the driven pair of smoothing wheels 29
in the direction toward the driving smoothing wheel 5, a
gearwheel 1 to be smoothed being held in operation clamped
as a workpiece under a high radial pressure between the
pair of smoothing wheels 5 and the single smoothing wheel
5. The gearwheel 1 to be smoothed is held axially clamped
so it is radially movable by a clamping device 16, which is
positioned on a C-shaped bracket 17, which is in turn
attached via a spring assembly 18 and via an eccentric 19
on a holding stand 21 on such a way that it allows vertical
oscillation of the gearwheel 1, which is only clamped
axially, but is mounted quasi-floating radially, via an
eccentric drive 20.
In order to be able to set the device for different sizes
of gearwheels 1 to be smoothed and/or different smoothing
wheels 5, the entire carriage 13 is movable together with
the carriage 12 in relation to a fixed vertical axis of the
clamping device 16 on the guide rails 11 via a small
positioning cylinder 15.
As shown enlarged in Figure 2, the operating region of the
device for smoothing gearwheels essentially includes three
smoothing wheels 5 having fixed or pivotable vertical axes
of rotation, of which a first smoothing wheel 5, referred to
herein as driving smoothing wheel 5, is positioned on the
carriage 12 and is driven by a motor 22.
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The two other smoothing wheels 29 are positioned in a pair
on the inner carriage 13 and may be pressed via the
pressure cylinder 14 in the direction toward the driven
smoothing wheel 5 in such a way that a gearwheel 1 to be
smoothed, which is positioned between them, may be pressed
against the smoothing wheels 5 using a force of 150 to
500 kg, for example.
Furthermore, the device is equipped with a spray nozzle 2,
which may have enough pressure applied to it via a pressure
generator 23, such as a pump, and a supply line 24 that a
fine vaporized oil spray mist is sprayable on a free
surface region of the gearwheel 1 to be smoothed during a
complete rotation of the gearwheel 1 to be smoothed. The
lubricant is applied after the rotating gearwheel 5 has
been engaged load-free, i.e., still without having a
pressure force applied to it, with the gearwheel 1 to be
smoothed. The nozzle 2 is positioned via a support block 25
and an angularly adjustable carrier 26 on the carriage 13
in such a way that optimized application of the minimum
quantity of lubricant may be performed through a very short
pump stroke. The short spray stream may be generated in
another way, however, such as through a valve-controlled
nozzle.
Furthermore, the air cooler 7, which operates according to
the Joule-Thompson affect, is also recognizable in Figure
2, which is connected to an air distributor 6, that directs
air, strongly cooled down to -50 C, for example, against
the smoothing wheels 5 to be cooled through three air
distributor lines 4 and cold air nozzles 8. If necessary,
more air distributor lines 4 may also be provided, even to
the gearwheel 1 to be smoothed. The air is generated by a
device 3 that generates an air stream, such as a pump or a
compressor positioned below the machine table 10.
