U.S. patent application number 13/231071 was filed with the patent office on 2012-01-05 for hydraulic detachable coupling.
This patent application is currently assigned to MITSUBISHI HEAVY INDUSTRIES, LTD.. Invention is credited to Taku Ichiryu, Shoki Yamashita, Tadao Yashiki.
Application Number | 20120001426 13/231071 |
Document ID | / |
Family ID | 38956661 |
Filed Date | 2012-01-05 |
United States Patent
Application |
20120001426 |
Kind Code |
A1 |
Yamashita; Shoki ; et
al. |
January 5, 2012 |
HYDRAULIC DETACHABLE COUPLING
Abstract
A hydraulic detachable coupling, which can transmit rated torque
in a manner stable to vibrations, and can fully withstand abnormal
torque. For this purpose, in a hydraulic detachable coupling (4)
mounted detachably on a rotor (1) of a steam or gas turbine or
other machine, a coupling sleeve (4b), which is fitted on a shaft
end portion of a casing penetrating shaft (2) in the rotor (1),
includes a taper hole portion (4b-a) which is interference-fitted
on a taper shaft portion (2a) of the shaft end portion by a
hydraulic pressure, and a straight hole portion (4b-b) having teeth
(13) engaging a plurality of teeth (12) formed in a straight shaft
portion (2b) of the shaft end portion, the taper hole portion
(4b-a) and the straight hole portion (4b-b) being located adjacent
to each other.
Inventors: |
Yamashita; Shoki;
(Takasago-shi, JP) ; Yashiki; Tadao;
(Takasago-shi, JP) ; Ichiryu; Taku; (Akashi-shi,
JP) |
Assignee: |
MITSUBISHI HEAVY INDUSTRIES,
LTD.
Tokyo
JP
|
Family ID: |
38956661 |
Appl. No.: |
13/231071 |
Filed: |
September 13, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12304844 |
Apr 7, 2009 |
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PCT/JP2007/053133 |
Feb 21, 2007 |
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13231071 |
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Current U.S.
Class: |
285/417 |
Current CPC
Class: |
Y10T 403/7035 20150115;
Y10T 403/7026 20150115; F16D 1/092 20130101; F16D 2001/0906
20130101; Y10T 403/1641 20150115 |
Class at
Publication: |
285/417 |
International
Class: |
F16L 21/00 20060101
F16L021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 18, 2006 |
JP |
2006-195204 |
Claims
1-4. (canceled)
5. A hydraulic detachable coupling mounted detachably on a rotating
shaft of a rotating machine, comprising: a coupling sleeve which is
fitted on a shaft end portion of the rotating shaft, the coupling
sleeve including an interference fit portion which is
interference-fitted on an outer peripheral surface of the shaft end
portion by a hydraulic pressure, and an engagement portion which
engages the outer peripheral surface of the shaft end portion at a
plurality of locations in a circumferential direction, the
interference fit portion and the engagement portion being located
adjacent to each other, wherein the engagement portion is a
straight hole portion having keyways formed therein, the keyways
corresponding to a plurality of keyways formed in a straight shaft
portion of the shaft end portion.
6. The hydraulic detachable coupling according to claim 5, wherein
one of the corresponding keyways is a groove of a rectangular cross
section into which a square key is inserted, and other of the
corresponding keyways are taper grooves of a semicircular cross
section into which round taper keys are inserted.
7. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation application of U.S.
Non-Provisional application Ser. No. 12/304,844, filed Apr. 7,
2009, which claims the benefit of PCT application
PCT/JP2007/053133, filed Feb. 21, 2007 and Japanese Application No.
2006-195204, filed Jul. 18, 2006, which are hereby incorporated by
reference.
TECHNICAL FIELD
[0002] This invention relates to a hydraulic detachable coupling
preferred for use in a rotor of a rotating machine such as an
electric generator, a steam turbine, a gas turbine, or a
compressor.
BACKGROUND ART
[0003] Generally, rotors of an electric generator, a steam turbine,
a gas turbine, or a compressor, for example, are coupled coaxially
by a rotor coupling (see Patent Document 1).
[0004] In the steam or gas turbine, gas seals (called mechanical
seals) 101 may be installed at portions of a rotor 100 which
penetrate a turbine casing, as shown in FIG. 15. These are
360.degree. circular (endless) components fitted from the shaft
ends of the rotor 100. The gas seal 101 needs to be periodically
detached and attached for maintenance and checkup.
[0005] To enable the gas seal 101 to be detached and attached,
therefore, a rotor coupling 102A, which is installed at the shaft
end of the rotor 100, is also designed to be capable of easy
removal and reassembly. In the illustrated example, for instance, a
coupling sleeve 102a of the rotor coupling 102A is increased in
diameter by application of a hydraulic pressure (see hydraulic
paths 103 in the drawing), and then the hydraulic pressure is
released, whereby the coupling sleeve 102a is interference-fitted
(hydraulically fitted) to the shaft end of the rotor 100. From this
state, on the other hand, a hydraulic pressure is applied again to
increase the diameter of the coupling sleeve 102a, whereby the
rotor coupling 102A can be removed from the shaft end of the rotor
100.
[0006] As shown in FIG. 16, moreover, there is a case in which an
involute spline tooth portion 104a cut in the outer periphery of
the shaft end of a rotor 100, and an involute spline groove portion
104b cut in the inner periphery of a coupling sleeve 102b of a
rotor coupling 102B are brought into splined engagement with each
other, and prevented by a press nut 105 from disengagement. [0007]
Patent Document 1: JP-A-2003-65006
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0008] With the rotor coupling 102A as shown in FIG. 15, rated
torque in a shafting for driving the electric generator can be
stably transmitted by a frictional force attributed to the
interference fit. However, there has been the problem that the
rotor coupling 102A cannot withstand abnormal torque (usually, 5 to
10 times the rated torque) occurring in a short-circuit accident or
asynchronous input which is a special accident of the electric
circuit of the electric generator. That is, during the occurrence
of abnormal torque, slip occurs at the surface of pressure contact
between the outer peripheral surface of the shaft end of the rotor
100 and the inner peripheral surface of the coupling sleeve 102a,
thereby inducing excessive vibration or damage.
[0009] The rotor coupling 102B as shown in FIG. 16, on the other
hand, can withstand abnormal torque because of its splined
engagement, and can be easily attached and detached. However, if
the rotor 100 has a shaft with a very large overall length (for
example, exceeding 7 meters), as in an upsized steam or gas turbine
or compressor, the rotor coupling 102B has presented the problem
that cutting of a spline, such as the spline tooth portion 104a or
the spline groove portion 104b (by a gear cutting machine), in the
shaft end is difficult from the viewpoint of equipment.
[0010] The present invention has been accomplished in the light of
the above-described situations. It is an object of the invention to
provide a hydraulic detachable coupling which can transmit rated
torque in a manner stable to vibrations, and can fully withstand
abnormal torque.
Means for Solving the Problems
[0011] A hydraulic detachable coupling according to the present
invention, intended for attaining the above object, is a hydraulic
detachable coupling mounted detachably on a rotating shaft of a
rotating machine, comprising: a coupling sleeve which is fitted on
a shaft end portion of the rotating shaft, the coupling sleeve
including an interference fit portion which is interference-fitted
on an outer peripheral surface of the shaft end portion by a
hydraulic pressure, and an engagement portion which engages the
outer peripheral surface of the shaft end portion at a plurality of
locations in a circumferential direction, the interference fit
portion and the engagement portion being located adjacent to each
other.
[0012] The hydraulic detachable coupling is characterized in that
the interference fit portion is a taper hole portion corresponding
to a tapering-off taper shaft portion of the shaft end portion.
[0013] The hydraulic detachable coupling is also characterized in
that the engagement portion is a straight hole portion having teeth
formed therein, the teeth engaging teeth formed in a straight shaft
portion of the shaft end portion.
[0014] The hydraulic detachable coupling is also characterized in
that the teeth of the engagement portion, except for one of the
teeth of the engagement portion making high accuracy engagement
without clearance, engage a plurality of the teeth of the shaft end
portion via taper spacers disposed on both sides of other of the
teeth of the engagement portion.
[0015] The hydraulic detachable coupling is also characterized in
that the engagement portion is a straight hole portion having
keyways formed therein, the keyways corresponding to a plurality of
keyways formed in a straight shaft portion of the shaft end
portion.
[0016] The hydraulic detachable coupling is also characterized in
that one of the corresponding keyways is a groove of a rectangular
cross section into which a square key is inserted, and other of the
corresponding keyways are taper grooves of a semicircular cross
section into which round taper keys are inserted.
[0017] The hydraulic detachable coupling is also characterized in
that the coupling sleeve is prevented from slipping off the
rotating shaft, by slipping-off preventing means secured to the
shaft end portion.
Effects of the Invention
[0018] According to the features of the present invention, the
interference fit portion by the hydraulic pressure can stably
transmit rated torque while maintaining satisfactory shaft
vibration characteristics, whereas the engagement portion can
sufficiently deal with abnormal torque. As a result, a hydraulic
detachable coupling having high durability and involving low
vibration can be realized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a side view of a rotor and a coupling showing
Embodiment 1 of the present invention.
[0020] FIG. 2 is an enlarged sectional view of a coupling portion
in FIG. 1.
[0021] FIG. 3 is a sectional view taken on line A-A in FIG. 2.
[0022] FIG. 4 is a sectional view taken on line B-B in FIG. 3.
[0023] FIG. 5 is a sectional view of a coupling portion showing
Embodiment 2 of the present invention.
[0024] FIG. 6 is a sectional view taken on line C-C in FIG. 5.
[0025] FIG. 7 is a sectional view taken on line D-D in FIG. 6.
[0026] FIG. 8 is a sectional view of a coupling portion showing
Embodiment 3 of the present invention.
[0027] FIG. 9 is a sectional view taken on line E-E in FIG. 8.
[0028] FIG. 10 is a sectional view of a coupling portion showing
Embodiment 4 of the present invention.
[0029] FIG. 11 is a view taken in the direction of an arrowed line
G in FIG. 10.
[0030] FIG. 12 is a sectional view taken on line H-H in FIG.
11.
[0031] FIG. 13 is a sectional view taken on line I-I in FIG.
12.
[0032] FIG. 14 is a sectional view taken on line J-J in FIG.
13.
[0033] FIG. 15 is a side view of a rotor and a coupling which
represent a conventional example.
[0034] FIG. 16 is a sectional view of another coupling according to
the conventional example.
DESCRIPTION OF THE NUMERALS
[0035] 1 Rotor [0036] 2 Casing penetrating shaft [0037] 2a Taper
shaft portion [0038] 2b Straight shaft portion [0039] 3 Gas seal
[0040] 4 Rotor coupling [0041] 4a Coupling flange [0042] 4b
Coupling sleeve [0043] 4b-a Taper hole portion [0044] 4b-b Straight
hole portion [0045] 5 Rotor [0046] 6 Spacer [0047] 7 bolt [0048] 8
Spiral groove [0049] 9a, 9b Hydraulic path [0050] 10a, 10b O ring
[0051] 11 Residual oil blowing hole [0052] 12, 12A, 12B Tooth
[0053] 13, 13A, 13B Tooth [0054] 14 Taper spacer [0055] 15 Press
plate [0056] 16 Clamping bolt [0057] 17 Spacer hold-down screw
[0058] 18 Press nut [0059] 19 Whirl-stop washer [0060] 20 Bolt
[0061] 21 Coned disk spring [0062] 22 Liner [0063] 23 Square key
[0064] 24 Round taper key [0065] 25, 26 Groove of rectangular cross
section [0066] 28a, 28b Taper groove of semicircular cross section
[0067] 29 Key hold-down screw [0068] 30 Screw hole
BEST MODE FOR CARRYING OUT THE INVENTION
[0069] A hydraulic detachable coupling according to the present
invention will now be described in detail by embodiments using the
accompanying drawings.
Embodiment 1
[0070] FIG. 1 is a sectional view of a rotor and a coupling showing
Embodiment 1 of the present invention. FIG. 2 is an enlarged
sectional view of a coupling portion in FIG. 1. FIG. 3 is a
sectional view taken on line A-A in FIG. 2. FIG. 4 is a sectional
view taken online B-B in FIG. 3.
[0071] As shown in FIG. 1, 360.degree. circular (endless) gas seals
(called mechanical seals) 3 are detachably (removably) installed at
casing penetrating shafts 2 in right and left portions of a rotor
(rotating shaft) 1.
[0072] A rotor coupling 4 is mounted at the shaft end of one of the
casing penetrating shafts 2. One end of a rotor 5 (see FIG. 2) is
coupled to the same shaft by a bolt 7 via a spacer 6 (not
absolutely necessary) through the intermediary of a coupling flange
4a of the rotor coupling 4. The rotor couplings 4 may be provided
on both of the casing penetrating shafts 2 (i.e., at opposite end
portions of the rotor 1).
[0073] The rotor coupling 4 is composed of a hydraulic detachable
coupling. That is, as shown in FIG. 2, the shaft end of the casing
penetrating shaft 2 is constituted of a taper shaft portion 2a of a
tapered form having a slightly smaller diameter than that of the
casing penetrating shaft 2, and a straight shaft portion 2b
connected to the leading end of the taper shaft portion 2a. A taper
hole portion (interference fit portion) 4b-a, which is formed on
the inner peripheral surface of a coupling sleeve 4b of the rotor
coupling 4 in correspondence with the taper shaft portion 2a, is
detachably mounted on the outer peripheral surface of the taper
shaft portion 2a by an interference fit attributed to a hydraulic
pressure.
[0074] In detail, a spiral groove 8 is formed on the outer
peripheral surface of the taper shaft portion 2a, and the spiral
groove 8 is supplied with a pressure oil from the end surface side
of the straight shaft portion 2b via hydraulic paths 9a, 9b during
mounting and removal of the rotor coupling 4. In FIGS. 2, 10a and
10b denote O rings which are located on both sides of the spiral
groove 8 and are provided on the outer peripheral surface of the
taper shaft portion 2a and on the circumferential surface of the
taper hole portion 4b-a. The numeral 11 denotes a residual oil
blowing hole formed in the coupling sleeve 4b in order to recover
the pressure oil after mounting or removal of the rotor coupling
4.
[0075] In the present embodiment, the straight shaft portion 2b,
and a straight hole portion (engagement portion) 4b-b of the
coupling sleeve 4b formed in correspondence therewith establish a
structure in which teeth 12 and 13 formed therein engage each
other.
[0076] As shown in FIGS. 3 and 4, the teeth 12 formed in the
straight shaft portion 2b are formed with a fanning cross section,
and the teeth 13 formed in the straight hole portion 4b-b are
formed with a rectangular cross section. In each portion of their
engagement, taper spacers 14 having a cone angle close to the angle
of friction are interposed on both sides of each tooth, except at
one location where the straight shaft portion 2b and the straight
hole portion 4b-b mesh with high precision without clearance for
phase alignment during mounting of the rotor coupling 4. For this
purpose, both side surfaces of the tooth 12 formed in the straight
shaft portion 2b are formed as taper surfaces corresponding to the
taper spacers 14.
[0077] In FIG. 2, the numeral 15 denotes an annular press plate
(slipping-off preventing means) which is secured by a clamping bolt
16 to the end surface of the straight shaft portion 2b of the
casing penetrating shaft 2 in order to prevent the rotor coupling 4
from slipping off after the rotor coupling 4 is mounted. The
numeral 17 denotes a spacer hold-down screw which is screwed into
the press plate 15 in order to push in the taper spacer 14.
[0078] Because of the above configuration, when a pressure oil is
supplied from a hydraulic pressure supply source (not shown) to the
spiral groove 8 of the taper shaft portion 2a via the hydraulic
paths 9a, 9b, with most of the coupling sleeve 4b of the rotor
coupling 4 being loosely fitted on the taper shaft portion 2a and
the straight shaft portion 2b of the casing penetrating shaft 2,
the diameter of the coupling sleeve 4b (taper hole portion 4b-a) is
increased by the hydraulic pressure.
[0079] When, in this state, the rotor coupling 4 is pushed in by a
suitable means, the coupling sleeve 4b (taper hole portion 4b-a) is
fitted deeply (to a maximum) on the taper shaft portion 2a. Then,
the supply of the pressure oil is stopped and, at the same time,
the hydraulic paths 9a, 9b are switched to a drain side to
discharge the pressure oil. By so doing, the coupling sleeve 4b
(taper hole portion 4b-a) is interference-fitted on the taper shaft
portion 2a. At the time of discharge of the pressure oil,
pressurized air is blown in through the residual oil blowing hole
11 to discharge the residual oil.
[0080] On this occasion, at the straight shaft portion 2b of the
casing penetrating shaft 2 and the straight hole portion 4b-b of
the coupling sleeve 4b, their teeth 12 and 13 engage in the
circumferential direction, with the taper spacers 14 being
interposed therebetween. For this engagement, phase alignment is
carried out at the one location, i.e., an engagement portion F
where high accuracy engagement takes place without clearance.
[0081] After the rotor coupling 4 is interference-fitted, the press
plate 15, which engages the rotor coupling 4 in a slipping-off
preventing direction, is clamped by the bolt 16 onto the end
surface of the straight shaft portion 2b of the casing penetrating
shaft 2. By so doing, the interference-fitted state of the rotor
coupling 4 is maintained. Moreover, the taper spacer 14 is pushed
in deeply by the spacer hold-down screw 16 which is screwed into
the press plate 15. Then, one end of the rotor 5 is coupled to the
coupling flange 4a of the rotor coupling 4 by the bolt 7 via the
spacer 6.
[0082] On the other hand, with the press plate 15 being detached
along with the spacer hold-down screw 16, the pressure oil is
supplied again from the hydraulic pressure supply source (not
shown) to the spiral groove 8 of the taper shaft portion 2a via the
hydraulic paths 9a, 9b. As a result, the diameter of the coupling
sleeve 4b (taper hole portion 4b-a) is increased by the hydraulic
pressure, whereby the interference-fitted state of the coupling
sleeve 4b (taper hole portion 4b-a) is released.
[0083] Then, simply upon supply of the hydraulic pressure, the
rotor coupling 4 is easily disengaged, together with the taper
spacers 14, from the casing penetrating shaft 2, for example, by
pulling the rotor coupling 4. Thus, the gas seals 3 can be
disengaged from the casing penetrating shaft 2 for replacement and
maintenance.
[0084] In the present embodiment, while the rotor 1 is rotating,
the rotor coupling 4 deals with rated torque (normal torque) by use
of frictional torque at the interference fit portion between the
taper shaft portion 2a of the casing penetrating shaft 2 and the
coupling sleeve 4b (taper hole portion 4b-a) under the hydraulic
pressure, and deals with abnormal torque, such as one during
short-circuiting of the electrical generator, by utilizing the
portion of engagement between the teeth 12 and 13 of the straight
shaft portion 2b of the casing penetrating shaft 2 and the straight
hole portion 4b-b of the coupling sleeve 4b.
[0085] Thus, in the rotor coupling 4, the interference fit portion
due to the hydraulic pressure has an interference margin sufficient
for the rotor 1 and the rotor coupling 4 to act as a single elastic
body in response to the lateral vibration of the shaft, so that
stable shaft vibration characteristics are obtained. A steam
turbine and a gas turbine generally rotate at a high speed and, in
order for them to be kept with minimal vibration, their axes have
to be held in position relative to each other at the portion of
coupling between the adjacent rotors, and this state has to be
stably maintained. In the present embodiment, the interference fit
portion is subject to fitting of the taper surfaces, and thus
functions effectively.
[0086] In response to abnormal torque, such as that in the
short-circuiting accident of an electric generator, which is
considered to occur several times or less frequently during the
total life of the steam or gas turbine, the portion of engagement
between the teeth 12 and 13 resists the marked slip of the rotor
coupling 4, and this is capable of preventing damage which makes
the continued use of the rotor 1 difficult. On this occasion, the
portion of engagement between the teeth 12 and 13 is brought into
engagement by the taper spacers 14 without play. Thus, all the
teeth can be simultaneously resistant during abnormal torque.
[0087] Furthermore, of the portions of engagement between the teeth
12 and 13, only one engagement portion F undergoes high accuracy
engagement without clearance. Therefore, an indexing mechanism as
in a gear cutting machine is not required. Even if the rotor 1 has
a considerably long shaft, it can be processed easily by an
ordinary processing machine. In other words, the introduction of
equipment, which is expensive, but is used with a low frequency,
can be avoided. This is very advantageous in the cost of
production.
[0088] The reasons why the taper spacers 14 are disposed at
positions on both sides of the tooth at the portion of engagement
between the teeth 12 and 13 are as follows: Abnormal torque in a
short circuit of the electrical generator as an accident appears as
a positive-negative alternate load, which has to be coped with by
such disposition. Also, accidental detachment has to be prevented
under an abnormally heavy load. Moreover, when the taper spacers 14
are mounted, their thickness adjustment is easy to make because no
play is present. When the taper spacers 14 are dismounted, they are
easy to withdraw. To fulfill all of these requirements, it is
preferred to adopt an angle close to the angle of friction as the
inclination of the spacer.
Embodiment 2
[0089] FIG. 5 is a sectional view of a coupling portion showing
Embodiment 2 of the present invention. FIG. 6 is a sectional view
taken on line C-C in FIG. 5. FIG. 7 is a sectional view taken on
line D-D in FIG. 6.
[0090] This is an embodiment in which at the portions of engagement
between the teeth 12A and 13A in Embodiment 1, the teeth 12A formed
in the straight shaft portion 2b are changed from a fanning cross
sectional shape to a rectangular cross sectional shape. Other
features are the same as those in Embodiment 1. Thus, the same
members as those in FIGS. 2 to 4 are assigned the same numerals as
in these drawings, and duplicate explanations are omitted.
[0091] According to this embodiment, the advantage that the
strength of the teeth 12A formed in the straight shaft portion 2b
can be enhanced is obtained, in addition to the same actions and
effects as those in Embodiment 1.
Embodiment 3
[0092] FIG. 8 is a sectional view of a coupling portion showing
Embodiment 3 of the present invention. FIG. 9 is a sectional view
taken on line E-E in FIG. 8.
[0093] This is an embodiment in which at the portions of engagement
between the teeth 12B and 13B in Embodiment 1, the teeth 12B formed
in the straight shaft portion 2b and the teeth 13B formed in the
straight hole portion 4b-b are engaged with each other, without
using the taper spacers 14, after processing by an ordinary
processing machine such as a lathe, and then performing polishing.
In this case, it cannot be expected for all the teeth to resist
abnormal torque simultaneously. However, because of the ductility
of the rotor 1 and the rotor coupling 4 comprising an alloy steel,
the load is borne, first of all, by the tooth having a little play,
sequentially by the tooth having more play, and finally by all the
teeth. Thus, no problem is posed.
[0094] In this embodiment, moreover, slipping-off of the rotor
coupling 4 is prevented by a press nut (slipping-off preventing
means) 18 which is screwed to the shaft end of the straight shaft
portion 2b, rather than by the press plate 15. In FIG. 8, the
numeral 19 denotes a whirl-stop washer which engages the rotor
coupling 4 to carry out whirl-stopping of the press nut 18. The
whirl-stop washer 19 is secured to the press nut 18 by a bolt 20.
The numeral 21 denotes a coned disk spring, and the numeral 22
denotes a liner.
[0095] In this embodiment as well, the same actions and effects as
those in Embodiment 1 are obtained.
Embodiment 4
[0096] FIG. 10 is a sectional view of a coupling portion showing
Embodiment 4 of the present invention. FIG. 11 is a view taken in
the direction of an arrowed line G in FIG. 10. FIG. 12 is a
sectional view taken on line H-H in FIG. 11. FIG. 13 is a sectional
view taken on line I-I in FIG. 12. FIG. 14 is a sectional view
taken on line J-J in FIG. 13.
[0097] This is an embodiment in which the engagement structure by
the teeth 12 and the teeth 13 at the straight shaft portion 2b and
the straight hole portion 4b-b in Embodiment 1 is changed to an
engagement structure by a square key 23 and round taper keys
24.
[0098] That is, at the straight shaft portion 2b and the straight
hole portion 4b-b, one of keyways corresponding to each other is
formed into grooves 26, 25 of a rectangular cross section into
which the square key 23 is inserted, while the other seven keyways
corresponding to each other are formed into taper grooves 28a, 28b
of a semicircular cross section into which the round taper keys 24
are inserted (see FIGS. 10 and 13).
[0099] Here, the grooves 26 and 25 of a rectangular cross section
are machined before the rotor coupling 4 (strictly, the taper hole
portion 4b-a of the coupling sleeve 4b) is mounted on the casing
penetrating shaft 2 (strictly, the taper shaft portion 2a) by
interference fit under the hydraulic pressure. After the square key
23 is mounted in the groove 26 of the rectangular cross section on
the side of the casing penetrating shaft 2 (strictly, straight
shaft portion 2b) by bolts 27, the rotor coupling 4 is axially
plunged and pressed in, with the square key 23 serving as a guide
for phase alignment. On the other hand, after the rotor coupling 4
is mounted on the casing penetrating shaft 2 by the interference
fit under the hydraulic pressure, the taper grooves 28a, 28b of the
semicircular cross section are formed by co-machining of the rotor
coupling 4 and the casing penetrating shaft 2. Then, the round
taper keys 24 are inserted into taper grooves of a circular cross
section which are formed from the taper grooves 28a and 28b of the
semicircular cross section.
[0100] In FIG. 10, the numeral 29 denotes a round taper key
hold-down screw which is screwed into the press plate 15 to hold
down the round taper key 24, and the numeral 9a denotes a screw
hole for connection of a pressure oil supply pipe. In FIG. 14, the
numeral 24a denotes an air vent passage for use during insertion of
the round taper key 24. The screw hole 30 is used also in
separately screwing a bolt into it and pulling out the bolt when
the round taper key 24 is to be detached. Other features are the
same as those in Embodiment 1. Thus, the same members as those in
FIG. 2 are assigned the same numerals as in this drawing, and
duplicate explanations are omitted.
[0101] According to the present embodiment, while the rotor is
rotating, the rotor coupling 4 can deal with rated (normal) torque
by use of frictional torque at the interference fit portion between
the taper shaft portion 2a of the casing penetrating shaft 2 and
the coupling sleeve 4b (taper hole portion 4b-a) under the
hydraulic pressure, and can deal with abnormal torque, such as one
during short-circuiting of the electrical generator, by utilizing
the engagement structure attributed to the square key 23 and the
round taper keys 24 at the straight shaft portion 2b of the casing
penetrating shaft 2 and the straight hole portion 4b-b of the
coupling sleeve 4b. The same actions and effects as those in
Embodiment 1 are obtained.
INDUSTRIAL APPLICABILITY
[0102] The hydraulic detachable coupling according to the present
invention is preferred for use in coupling the rotors of a rotating
machine coaxially.
* * * * *