Note: Descriptions are shown in the official language in which they were submitted.
lZ~633
BACK~ROUND OF THE INVENTION
The present invention relates to a new and
improved construction of a shaft coupling and a method o~
operating the same in order to positively interconnect with
an interference fit or ~rictionally two shafts which are to
be operatively coupled ~lith one another, in order to
reliably transmit a rotational moment or torque between
~uch ~wo shafts.
In its more specific aspects, the shaft
coupling of ~he ~resent development serves for the
frictional connection of two coaxially arrange~ shafts each
having substantially cylindrical shaft ends or end
sections. The shaft coupling contains an inner sleeve or
bushing possessing a substantially cylindrical bore having
a slight over-dimension in relation to the cylindrical end
sections or portions of the shafts and a slightly conical
outer surface or taper. Additionally, there is provided an
oute~ sleeve or bushing possessing an inner conical surface
or taper which is suitable for coacting with the conical
outer surface or taper of the inner sleeve. The outer
sleeve is provided with a bore for the infeed of hydraulic
medium at a high pressure between the conical surfaces or
tapers of the inner and outer sleeves. The outer sleeve
can be displaced by using a relatively modest amount of
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~2~ 33
force upon the inner sleeve int~ an operating or workingposition in which the inner sleeve is compressed by the
outer sleeve and firmly pressed against the end portions or
sections of th~ shafts in such a manner that there is
provided a frictional connection between both of the
shafts. The ou-ter sleeve~ has support sections or portions
which, in the operating p~sition of the shaft couplil~g, are
intended to encircle the end portions of the shafts.
Between such support portions or sections there is located
an intermediate portion or section which, in the operating
position of the shaft coupling, is located at the region
between both of the shafts.
Such types of shaft couplings, among other
things, arP used for interconnecting propeller shafts of
marine vessels with their drive shafts. They have the
advantage that there can be avoided the use of keyways,
they require very little space and can be easily mounted
and again dismantled.
However, the heretofore known constructions of
such shaft couplings are associated with the drawback that
during the driving-up of the outer sleeve upon the inner
sleeve the latter must be supported along its entire
length. At the location wherever there is present a gap,
typically between the confronting end portions or sections
121~;33
of the shafts to be interconnected, in other words at those
locations where the inner sleeve is not supported, the
inner sleeve can become damaged by virtue of the high
prevailing hydr,aulic pressures.
Thus, for incitance, to counteract or mitigate
against this appreciable shortcoming both ends of the
shafts which are to be interconnectea must be arranged or
adapted so as to abut one another without the formation of
any intermediate gap therebetween. Under certain
~0 circumstances this can require that there be undertaken
expensive adaptation or modification work during the
mounting of the shaft coupling upon the shafts.
On the other hand, situations are encountered
in practice, such as for example in the ca~e of adjustable
pitch propellers, where two hollow shafts should be
interconnected which contain in their hollow spaces or
passageways tubular pipes or conduits. As a yeneral rule,
these tubular pipes are provided with pipe couplings at the
connection location of both shafts, in order to thus be
2n able to disconnect, by means of such pipe couplings, the
propeller along with its propeller shaft completely from
the drive shaft.
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121~;33
With the present day constructions of shaft
couplings of the aforementioned type it is necessary, in
the aforementioned instance, to fit bipartite ring-shaped
insertion elem~nts into the intermediate space or gap
between both of the sha~t ends, in order to provide an
effective support of the inner sleeve during the assembly
of the shaft coupling wh;ich entails drawing or driving-up
the outer sleeve along the inner sleeve. Inasmuch as this
work only can be performe~d after the installation of the
propeller at the marine vessel it is both cumbersome and
expensive.
SUMMARY OF THE INVENTION
Therefore, with the foregoing in mind it is a
primary object of the present invention to pxovide a new
and improved shaft coupling and method of operating the
same which is not afflicted with the aforementioned
drawbacks and limitations of the prior art shaft coupling
constructions and the methods of operating the same during
the mounting and dismantling of the shaft coupling at and
from the shafts to be interconnected.
Another important object of the present
invention is directed to a new and improved construction of
lZ1~33
a shaft coupling of the previously mentioned type which
affords a relatively simple, reliable and safe
interconnection of two shafts, specifically independent of
whether the shafts abut one another without any
intermediate splace or gap therebetween or whether there is
present an intermediate space or gap between these shafts.
Still a furt:her significant object of the
present invention is directed to a new and improved
construction of shaft coupling for reliably, positively and
safely interconnecting in a most simple and effective
manner two shafts with one another in order to provide for
the transmission of relatively high torques or rotational
moments therebetween, which shaft coupling is relatively
simple in construction and design, quite economical to
manufacture, extremely reliable in operation, easy to use,
and affords relatively simple mounting and dismantling of
the shaft coupling at the shaft ends of the shafts to be
interconnected, without the danger of damaging the shaft
~oupling even in those situations where the shaft ends do
not abut one another and the inner sleeve of the shaft
coupling is thus not supported fully over its entire
length.
A further important object of the present
invention is directed to a new and improved construction of
633
shaft coupling and method of operating the same which
allows for the reliable and positive torque-transmitting
interconnection of the shaft ends of two shafts which are
to be interconnected with one anothex, without the need for
any time-consuming and expensive ~ccommodation or
adaptation wor~ to prote,ct the inner sleeve of the shaft
coupling against damage due to the fact that it is
partially unsupported when the shaft ends are spaced from
one another.
Now in order to implement these and still
further objects of the invention, which will become more
readily apparent as the description proceeds, the shaft
coupling of the present development is manifested by the
features that, both of the support portions or sections are
each provided with at least one bore for the infeed of the
pressurized fluid medium, and that at the intermediate
portion or section or either the outer sleeve or inner
sleeve there is provided at least one outflow or discharge
bore for the withdrawal or discharge of the hydraulic
pressurized fluid medium.
Although not absolutely crucial it is
preferable if the outflow bore or equivalent outflow
facility is formed in the outer sleeve or bushing.
121~33
However, a constructional embodiment is
conceivable wherein the outflow bore or port or the like is
formed in the inner sleeve or bushing. When
intarconnecting hollow shafts, the confronting ends of
which are arranged in spaLced relationship from one another,
the hydraulic pxessurized fluid medium can unobstructedly
flow-out into the hollow space or passageways of the hollow
shafts. This embodiment is particularly advantageous in
those instances where the movement or displacement of the
1~ outer sleeve upon the inner sleeve, during the mounting of
the shaft coupling, is greater than the gap or space
between both of the sha.t ends. The outflow or withdrawal
opening for the pressuri~ed fluid medium can be arranged
exactly above such gap or space between the confronting
shaft ends.
The inventive shaft coupling can be constructed
such that the cylindrical bore or passageway of the inner
sleeve is stepped in such a manner that it comprises two
substantially cylindrical portions or sections having
different diameters, and thus is suitable for the
interconnection of shaft ends possessing corresponding
diameters. A connection of such type of shaft ends was not
possible with the heretofore known constructions of sleeves
of the state of the art shaft couplings.
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1211~33
Moreover, the larger diameter cylindrical
section or portion of the support sec-tion or portion of the
inner bushing likewise can be structured to possess a
larger diameter. Consequently, there is obtained a shaft
coupling whose inner sle~3ve or bushing can possess the same
thickness at both support portions or s~ctions thereof,
notwithstanding the conical outer surface or taper of such
inner sleeve. This can ~be advantageous for the design and
computation of the dimencsions of the shaft coupling.
Preferably, the outflow or discharge bore can
have operatively associated therewith a substantially
ring-shaped or annular groove. This ring-shaped groove
ensures for an essentially uniform outflow or discharge of
the hydraulic medium-about the circumference of the shaft
coupling.
As already alluded to above the invention is
not only concerned with the aforementioned novel and
improved construction of shaft coupling, but also relates
to a unique method of operating such shaft coupling for
interconnecting the shaft ends of two coaxially arranged
shafts and for releasing the mounted shaft coupling. To
that end there is mounted a shaft coupling constructed
accordinq to the invention upon the confronting ends of the
two shafts which are to be interconnected, the shaft
~ 3
coupling having an inner sleeve or bushing provided with a
sli~htLy conical outer surface or taper, and an outer
sleeve or ~ushing provided with an inner conical surface or
taper. There i.s then infed a hydraulic pressurized fluid
medium from the! region of at least one support portion or
section of the shaft coupling located remote from the
confronting shaft ends through the contacting surfaces or
interface of the taperecl inner and outer sleeves, this
hydraulic pressurized fluid medium flowing along the
interface or contacting surfaces of the inner and outer
sleeves towards a region where the hydraulic pressurized
fluid medi~m can experience a reduction in its pressure,
e.g. towards atmospheric pressure, this pressure reduction
region being located in a plane extending between the
confronting shaft ends. By virtue of such flow of the
hydraulic pressurized fluid medium at the interface between
the contacting surfaces of the inner and outer sleeves, the
outer sleeve is raised from the inner sleeve to an extent
sufficient to permit displacement or driving of the outer
sleeve in a predetermined mounting direction. The outer
sleeve is then displaced or drive~ in such mounting direction, in
order to compress the inner sleeve against the confronting ends
of the shafts to be interconnected, the flow of hydraulic
pressurized fluid medium through the interface between the outer
and inner sleeves is discontinued, and the shaft ends are
positively
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lZ1~33
interconnected with one another by the shaft coupling. For
de-mounting or dismantling the shaft coupling the
procedures are essentially the same, except that the outer
sleeve is displaced in t]he opposite direction with respect
to the mounting direction.
Advantageous]y, although not necessarily, the
shaft ends are spaced at their confronting ends from one
another, although the confronting shaft ends could be
arranged in abutting cont:act with one another at such ends.
Moreover, the hydraulic pressuriæed fluid medium can he
advantageously infed from the two support sections or
portions of the outer sleeve to the interface between the
contacting surfaces of the outer and inner sleeves in
opposite directions towards the region where the hydraulic
pressurized fluid medium is permitted to undergo a
reduction in pressure. In such case the region where the
hydraulic pressurized fluid medium is able to experience a
reduction in pressure is located intermediate such support
sections or regions.
lZ~33
BRIEF DESCRIPTION OF THE DRAWINGS
The .invention will be better understood and
objects other 1than those set forth above, will become
apparent when consideration is given to the following
detailed description thereof. Such description makes
reference to the annexed drawings wherein:
Figure l is a partial fragmentary sectional
view of a first exemplary embodiment of shaft coupling for
interconnecting two shafts, here for instance a propeller
shaft with a drive shaft; and
Figure 2 is a fragmentary sectional view,
similar to the showing of Figure l, depicting a different
exemplary embodiment of inventive shaft coupling.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Describing now the drawings, it is to be
understood that only enough of the construction of the
shaft coupling and related shafts which are to be
interconnected has been shown in the drawings as needed for
those skilled in the art to readily understand the
underlying principles and concepts of the present
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lZ11~33
development, while simplifying the showing of the drawings.
Turning attention now to the first exemplary embodiment of
Figure 1, it will be seen that the sha~t coupling 1 thereof
serves to interconnect, ~or instance, two hollow shafts 2
and 3 with one another. It can be assumed that one of the
shafts constitutes, for instance, the propeller shaft of an
adjustable pitch propeller and the other shaft constitutes
a drive sha~t for driving the propeller shaft. In the
event that there should be driven an adjustable pitch
propeller then the bores or passageways 4 and S of the
shafts 2 and 3, respecti~ely, are usually provided with not
particularly illustrated but conventional tubular pipes or
pipe conduits or the like for the infeed and the outfeed or
return of a suitable hydraulic pressurized fluid medium,
typically oil, in order to actuate the propeller, and even
under certain circumstances electrical lines or the like
can extend through these bores or passageways 4 and 5 of
the shafts 2 and 3. In such environment of use there are
provided in the illustrated gap or space 6 between the
confronting ends or end faces 23 and 24 of the shafts 2 and
3, respectively, suitable couplings for disconnecting such
pipings or conduits during the disassembly of one of the
shafts, especially if, for instance, the other shaft should
not be positionally shifted.
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~Zl~t;33
The exemplary embodiment of shaft coupling 1
depicted in Figure 1 possess an inner slee~e or bushing 7,
an outer sleeve or bushing 8 as well as a closure ring or
ring member 10 or equiva].ent structure.
The inner sleeve or bushing 7 possesses a
substantially cylindrica:L bore or passageway 11 having a
slight ovPr-dimension of~, for instance 0.15 mm .in relation
to the diameter D of the illustrated but not particularly
referenced end sections or portions of the shafts 2 and 3.
Aaditionally, the inner sleeve or bushing 7 has a slightly
conical outer surface or taper 12 having a taper of, for
instance 1:50 to 1:80. At the smaller end the inner sleeve
7 is provided with external threads or threaded portion 13
as well as with a sealing ring 14.
The outer sleeve or bushing 8 has an inner
conical surface of taper 15 which is suitable for coaction
with the outer conical surface or taper 12 of the inner
sleeve or bushing 7. This means that both the outer and
inner sleeves have the same taper, and that the diameter of
the inner sleeve 7 is chosen in accordance with the
requirements for forming the requisite frictional
connection or interference fit and for the release thereof.
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12~633
The closure ring or ring member 10 is provided
with internal threads or threaded portion 16 threaded onto
the external threads or threaded portion 13 of the inner
sleeve 7. Moreover, the closure ring member 10 possesses a
substantially cylindrical bore 17 which merges with the
internal threads 16, this cylindrical bore 17 sealin~ly
coacting with the sealin~ ring or seal structure 14 of the
inner sleeve 7. At its outside or outer circumference the
closure ring member 10 is provided with a substantially
cylindrical surface 18 in which there is mounted a sealing
ring 20 or equivalent structure which sealingly coacts with
a substantially c~lindrical bore 21 formed at the end of
the outer sleeve or bushing 8. The substantially
cylindrical bore 21 forms in conjunction with the closure
ring member lO a cylinder chamber or space 22, the purpose
of which will be described more fully hereinafter.
Figure 1 depicts the shaft coupling 1 in its
operating or work position, i.e. in a position in which the
outer sleeve or bushing 8, with the aid of the conical
surfaces or tapers 12 and lS, compresses the inner sleeve
or bushing 7 in such a manner that the depicted end
portions or sections of the shaft 2 and 3 are securely
clamped in the inner sleeve 7. This clamping action or
interfe~ence fit is o~ such an intensity that the friction
which prevails is sufficient for transmitting the requisite
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33
rotational moment or torque from the drive shaft to the
driven shaft. In this position the shaft coupling 1, and,
in particular, its outer sleeve 8 has two support sections
or portions A a~s well as an intermediate section or portion
B located therebetween, and such support sections or
portions A and intermediate section or portion B may be
considered to be likewise co-extensively present at the
inner sleeve or bushing 7. The intermediate portion B
extends beyond the axtent of the intermediate gap or ~pace
6 between the confronting end surfaces 23 and 24 of the
shafts 2 and 3, respectively~ The support portions or
sections A extend from the relevant end surface of the
related shaft up to the location where there terminates the
clamping action between the sleeves 7 and 8, i.e. beyond
the region where the conical surfaces or tapers 12 and 15
contact one another.
As also will be evident by inspecting Figure 1,
there is pro~ided in the outer sleeve or bushing 8, and
specifically at locations disposed within the support
sections or portions A, infeed ~ores or openings 30 for the
infeed of a suitable pressurized fluid medium, here
hydraulic pressurized oil, during the mounting and
dismantling of the shaft coupling 1. At one location,
~hich in the operating position of the shaft coupling 1 is
located in the intermediate portion or section B, there is
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lZ~33
arranged an oufflow or discharge bore or opening 31 for the
hydraulic medium. Into t.he intermediate space of the bore
21 there opens an infeed bore 32. The infeed bores 30 have
operatively ass.ociat~d therewith ring-shaped or annular
grooves 33 which ensure for a proper distribution of the
infed oil about the circ~lmference of the surface or taper
15. The outflow bore or opening 31 is also provided with
an appropriate groove 34, preferably a ring-shaped groove,
in order to render possible the uniform outflow of the
hydraulic medium about the circumference of the shaft
coupling 1.
If it is desired to release the shaft coupling
1 depicted in Figure 1 in such a manner that the shafts 2
and 3 can be disconnected from one another, then in
conventional manner there is infed pressurized oil at an
extremely high pressure through the infeed bores 30,
whereupon the outer sleeve 8 is moved or driven towards the
left of the showing of Figure 1 upon the conical surface or
taper 12 of the inner sleeve 7. Conse~uently, the clamping
action previously exerted upon the inner sleeve or bushing
7 is eliminated, so that such compressible inner sleeve 7
can now again expand and there is released the frictional
connection or interference fit between the inner sleeve 7
and the ends or end portions of the shafts 2 and 3. The
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1211~33
shaft coupling 1 can be laterally displaced upon the shafts
2 and 3.
On the other hand, if the shaft coupling 1 is
to be brought into its operating or work position, by means
of which it positively interconnects the shafts 2 and 3 by
virtue of the aforedescribed frictional action or
intererence fit, then the outer sleeve 8 must be
positionally mounted or arranged upon the inner sleeve 7 in
the depicted operating position. This is accomplished in
the manner that here also pressurized oil is infed through
the bores 30 and that at the same time other pressurized
oil is infed through the bore 32 into the cylindrical
chamber or space 22. The pressurized oil introduced
through the bores 30 between the interface contacting
surfaces of the conical surfaces or tapers 12 and 15
expands the outer sl~eve or bushing 8, so that this outer
sleeve 8 can be moved upon the conical surIace or taper 12
of the inner sleeve 7 in the clamping direction. This
movement is accomplished under the driving action of the
~0 pressurized oil which is effective in the cylinder chamber
or space 22.
These operations are well known in the art from
the heretofore known constructions of shaft couplings. On
the other hand, according to the invention there is
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lZ11~33
importantly provided the aforementioned outflow or
discharge bore 31 or equivalent structure and which is
equipped with an annular or ring-shaped groove 34. As
previously expl,ained, this outflow or discharge bore 31 is
located at the intermediate section or portion B which
corresponds to the intermediate gap or space 6 between the
end surfaces or ends 23 and 24 of the shafts 2 and 3,
respectively. This outflow bore 31 allows fox an outflow
of the oil, and particularly at that region where the inner
sleeve or bushing 7 is not supported and which could
otherwise become damaged by the action of the extremely
high pressure of the hydraulic medium, which can assume a
value of up to approximately 1000 bar. With the previously
described mounting of the inventive shaft coupling 1 and as
soon as the slightest interfacing gap forms between the
conical surfaces or tapers 12 and 15 under the action of
the inputted or infed hydraulic medium, such infed
hydraulic medium can outflow through the outflow bore 31
and loses its pressure. Therefore, there is unnecessary
the previously required exact accommodation or adaptation
of the length of the shafts 2 and 3 in such a manner that
their end surfaces 23 and 24 abutted one another without
any intermediate space or gap therebetween, or the
otherwise conventionally employed technique of
incorporating an exactly fitted bipartite support ring in
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12~ 3
the intermediate gap or space 6, both of which constitute
extremely expensive measures.
Finally, in Figure 2 there is depicted a
further possib]e construction of the inventive shaft
coupling, wherein there is provided a particular design of
the outflow or discharge bore 31 for use with hollow shafts
2 and 3, particularly as encountered in the case of
adjustable pitch propelle!rs. In this instance the outflow
or discharge bore 31 is formed in the inner sleeve ox
bushing 7 and opens into the intermediate gap or space 6
between the confronting ends of the shafts 2 and 3.
In such Figure 2 there has also been indicated
the possibility of interconnecting, by means of the
inventive shaft coupling, two shats 2 and 3 having
diferent diameters Dl and D2~ Preferably, the inner
sleeve or bushing 7 is constructed such that the part of
its substantially cylindrical bore or passageway possessing
the larger diameter D~ corresponding to the larger shaft
diameter D2 is formed in the support section or portion A
of the inner sleeve or bushing 7 which likewise possesses
the larger diameter.
Also, it is finally to be observed that in the
arrangement of Figure 1 the shafts 2 and 3 are shown
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6~3
provided with pressed-in or shrunk-fitted support sleeves
or bushings 35 which ensure for an appropriate
reinforcement o:f the shaits 2 and 3 against the outer or
external pressw~e of the shaft coupling 1.
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