Note: Descriptions are shown in the official language in which they were submitted.
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3. BACKGROUND OF INVENTION
The present invention relates to a support device which supports the
both ends of the shaft of a heavy rotatable object, particularly of a large-
sized ancl heavy-weight turbine rotor for a power generator for checking and
repa;rillg them ancl easily achieves adjus~men~ of horizontal levelling.
Conven tionally, the roller support base, for example, of the turbine
rotor for power generator which rotatably supports one end of the shaft has
been mounted on the base frame with plurality of adjusting bolts. Moreover,
such base frame has been generally installed on the floor surface not
specially strengthened. Therefore, even if an accurate horizontal levelling of
the roller support base is obtained previously by means of the adjusting bolts,
when the turbine rotor is once placed on the roller support base, the Eloor
surface is distorted or warped by the weight of said roller support base
resulting in poor levelling. Such poor levelling or distortion of floor surface
produces a considerable degree of thrust on the supporting rollers of roller
support base. This thrust is enhanced by deflection of rotor shaft. Thereby,
the turbine is encountered with irregular rotation including movement in the
axial direction. Accordingly, not only check and repair of turbine become
extremely difficult and cumbersome, but also, in extrem~e cases, such
irregular rotation results in partial abrasion of supporting rollers or rupture
of them in some cases. This makes check and repair very dangerous.
Consequently, further level adjustment is essential for preventing such
situation, but it has always required much difficulty followed by a great
expenditure of time and labor.
The inventors of the present invention have proposed, in the Japanese
Patent Application No. 168450/1981, a support device for checking and
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repairing a heavy rotatable object such as a turbine rotor providing an
automatic level adjusting mechanism which simplifies the level adjustment by
eliminating defects of existing support devices. Narnely, such device can
automatically align the axis of the heavy rotatable object with the axis of
support rollers. ~lowever, such a support device for checking and repairing
the heavy rotatable shaft which has the construction shown in Fig. 1, has not
ye-t been considered perfect in such a point that it results in the movement of
a turbine rotor (b) in the axial direction, although a little, after it is placed
on the roller support base (a) and the turbine rotor is started to rotate. Such
movement in the axial direction is supposed to occur due to the following
causes.
Since the roller support base (a) is suppor ted by the hemi spherical
support (c), the axis of the turbine rotor (b) and the roller (d) supporting the
end of the turbine rotor (b) must ideally be formed in parallel when the
turbine rotor (b) is placed on the roller support base (a). Moreover, even
when the turbine rotor (b) rotates by way of the roller (d), any thrust load
must not be generated not incurring any movement of rotor in the axial
direction so long as the parallelism between the axes of the rotor (b) and the
roller (d) are surely kept. However, practically, both axes of the rotor (b) and
the roller (d) are not formed in parallel because of some reasons, for
example, indicated below.
(a) Machining error
(b) Assembling error
(c) Unbalance of roller support base (a) before placing the turbine rotor
(b)
(d) Unbalance of roller support base (a) after placing of the turbine
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rotor (b) or resultant deformation
(e) Effect of driving force
(E) Effect of friction
1he causes (a) to (d) are considered to bring about following phenomena.
(1) Destroying parallelism (alignment) between the axes of the turbine
rotor (b) ancl roller (d).
(2) Destroying a uniform applying of a contact pressure between the rotor
(b) and roller (d) and changing oE the inclination of the turbine rotor (b)
and roller shaft (d) generated when a drive force is applied.
~ lere, it is supposed the condition (before start of operation) where the
rotor (b) is only placed on the roller support base (a) (Refer to Fig. l~)o
~lthough the horizontal levelling is a little poor as explained previously
because of above-listed causes, the system as a whole is balanced as shown in
Fig. 2. However, this condition does not guarantee that a pressure between
the turbine rotor (b) and roller (d) is uniformly distributed in the axial
direction. Rather, the pressure is considered to be inwardly (blade side) or
outwardly concentrated. To be more in detail, if the inner pressure of one
roller (d) of the roller support base (a) in the driving side is, for example,
high~ a resultant pressure at the inside of the other roller (d) also becomes
high. Accordingly, the moments at the center of the hemi spherical support
mechanism (c) must be mutually cancelled.
When a driving force is applied under this condition, a larger tangent
force is transmitted in the high pressure side and thereby a reacting force
resulting from the turbine rotor (b) generates unbalanced moments at the
center of hemi spherical support mechanism. As a resultj the roller support
base (a) generates rotating deflection in the direction of such moment as
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shown in Fig. 3. If a gradient is thus generated between the axis of the
turbine rotor (b) and the axis of the roller (d), the pressure and the tangent
force are redistributed, balancing the moments at the center of the hemi
spherical support mechanism (c). Further, when the turbine rotor is rotating
in the conclition as shown in Fig. 3, the turbine rotor (b) moves in the axial
direction. If it is rotated reversely, a tangent force is generated reversely,
resulting in a rotating deflection directed to the roller support base (a).
Therefore, the turbine rotor (b3 also moves in the same direction as explained
above.
If the movement is considered to occur in the axial direction because of
the reason described above, the roller support base (a) rnust rotate only a
little in such a moment when the turbine rotor (b) is driven.
From the above observation and analysis, following measures are
considered effective for making such movement in the axial direction as
small as possible.
(1) The roller support base (a) is fixed under the condition that the rotor (b)
is placed on the support base (a) so that the base (a) is no longer rotated
even with a driving force on a horizontai plane.
(2) In this case, if the roller suppGrt base (a) is fixed by screwing, the
movement can further be kept small through the adjustment by slightly
rotating the roller support base (a) in accordance with direction and
amount of movement the base (a) checked trially by rotating the
turbine rotor (d).
The present invention has been derived from such findings and
experiences and intended to provide a support device for checking and
repairing a heavy rotatable object which further simplifies the levelling or
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the alignment and ensures, a rnore accurate and safer check and repair by
eliminating the movement in the axial direction of turbine rotor which has
been generated by driving the turbine rotor in the existing system.
In summary, the present invention relates to a support device for
checking and repairing a heavy rotatable objec~, wherein such device
comprises a pair of self-aligning support structures for rotatably supporting
both ends of the heavy rotatable object. In each support structrue, a roller
support base supporting rotatably the end of the shaft of the heavy rotatable
object is supported on an adjustable surface plate of the base frame by means
of a hemi spherical support mechanism, and moreover a jig for adjusting the
horizontal rotating position of the roller support base around the vertical axis
o~ a hemi spherical support mechanism is mounted in the periphery of an
adjustable surface plate.
4. BRI~F DESC~IPTION OF THE DRAWINGS
Fig 1 shows an enlarged side elevational view including a partial cut-
away portion of the conventional support device ~or checking and repairing
the heavy rotatable shaft. Fig. 2 and Fig. 3 are explanatory views showing
the horizontal levelling operation by the same support device. Fig.--h is a plan
view of the support device for checking and repairing the heavy rotatable
object to which the present invention is applied. Fig. 5 is a front view of the
same support device. Fig. 6 is a cross-sectional view along the line 1-1 in
Fig. 4. Fig. 7 is a side elevational view including a partial cut-away portion
of the drive-side support structure. Fig. ~ is an enlarged front view of the
mounting portion of the roting position adjusting jig. Fig. 9 is a plan view of
the same support structure. Fig. 10 and Fig. 11 are a plan view and a front
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view of the same support structure indicating the mounting position of the
rotating position adjusting jig. Fig. 12 and Fig. 13 are explanatory views
showin~ the vertical levelling or al;gnment of the support structure before
and aEter the cl;sposition oE the heavy rotatable object. Fig. 14 and Fig. 15
show axis alignrnen t in the horizontal direction of the support structure
before and after the impellers are mounted.
5. DETAILED DESCRIPTION OF DISCLOSURE
A preferred embodiment of the support device of the present invention
is hereinafter disclosed in detail in conjunction with the attached drawings.
(Refer to Fig. 4 to Fig. 11.)
In the drawings, numeral (1) is a drive-side roller support base, while
numeral (1') is a follower-side roller support base. These roller support bases
(1) and (1') are supported respectively at their centers on the adjustable
surface plates (l~) and (~') of the base frames (3),(3') by means of the hemi
spherical support mechanisms (2~ and (2').
The drive-side roller support base (1) is provided with a pair of drive
rollers (5)9 (5). The rotating shafts (6~, (6) of these rollers (5), (5) are
respectively supported at the right and left sides by the bearings ~) and (7).
Moreover, the worms (11), (11) provided on the power transmission shaft (10)
of the geared motor (9) are engaged with the worm wheels (8), (8) provided at
the both ends of said rotatlng shaft. Thereby, the drive rollers (5), (5) rotate
synchronously, causing the one end (12) of the shaft of the turbine rotor
supported by such rollers (5), (5) to rotate at a speed as low as 0.3 rpm.
Meanwhile, the follower-side roller support base (1') has such a simple
structure that the shafts (6'), (6') of a pair of follower-side rollers (5'); (5') are
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supported by the bearings (7'), (7') as in the case above and the other end (12)
of the shaft of the turbine rotor is rotatably supported by these roller (5'),
(5'). The above drive-side rollers and follower-side rollers are generally made
of specially reinforced plastic materials. Furthermore, a means for weight
balance is addecl adequately to the drive-side roller support base (1).
Said hemi spherical support mechanisms (2), (2') are disposed at the
center of respective roller support bases (1), (1'). Each mechanism comprises
a vertical support shaft (21), (21') which has the top or upper end thereof
formed approximately in a hemi spherical shape and hemi spherical-recessed
pad (22), (22') which is uniformly engaged with the hemi sherical top of
vertical support shaft (21), (21'). Although in the drawings, the support shafts
(21), (~1') are provided at the center of adjustable surface plate (4), (4') on the
base frames (3), (3') and ~he hemi spherical-recessed pads (22), (22'), also at
the center of roller support bases (1), (1'), they may also be mounted upside
down respectively. In addition, a suitable lubricant is applied to the contact
surfaces of hemi spherical support mechanisms (2), (2'). It is also preferable
to provide compression springs (13~, (13') between the roller support bases (1),
(1'~ and adjustable surface plates (4), (4') so as to make the roller support
bases (1), (1') resiliently return and take a position parallel to the surface
plates (4), (4').
~ suitable gap or clearance must be provided between the adjustable
surface plates (4), (4') and the upper roller support bases (1), (1') so as to allow
the roller support bases (1), (1') to sufficiently tilt in all radial directions on
the hemi spherical support mechanisms (2), (2'). Moreover, the surface plates
(4), (4') are mounted on the base frames (3), (3') with plurality of adjusting
bolts (14), (14') so that they can be vertically adjusted freely ~o the desired
height. Numerals (15), (15') are guide pins. This adjusting means is a well
known method.
The present invention is substantially characterized by incorporating a
following structure to the above basic structure. Namely, a jig (29) for
adjustillg th~ horizontal rotating positions of the roller support bases (1), (1')
around the herni spherical support mechanisms (2), (2') is attached to the
periphery of the adjustable surface plates t4), (4'). Such rotating position
adjusting jig (29) can be installed, as shown in Fig. 4 and Fig. S. L-shaped
brackets (30), (30') are mounted in the Eront and rear sides of the adjustable
surface plates (4), (4') symmetrically to the axis of the shaft of the turbine
rotor (A) with a specified interval, the adjusting bolts (31), (31') are screwed
to the upper ends of the same L-shaped bracl<ets (30), (30'), and the end points
of the bolts (31), (31') come lnto contact with the corresponding side edges of
roller support bases (1), (1'). It is also enough to mount such rotating position
adjusting jig only to the drive side.
~ ig. 8 and Fig. 9 show another embodiment of the rotating position
adjusting jig (29). Numeral (29a) is a fixed plate attached by a coupling bolt
(29b) to the periphery of the adjustable surface plate (4). This fixed plate
(29a) is provided with a hollow groove (29c) at its upper~portlon allowing
insercion of a distal portion of a projection (29d) which has the proximal end
thereof connected to the periphery of the roller support base (1), with gaps
(c). In addition, numerals (29e), (29f) indicate adjusting bolts screwed to
vertical portions (29g) located in both sides of such hollow groove (29c) and
these bolts (29e), (29f) move forward or backward to/from the projection
(29d) and also abut therewith. By adjusting amount of movement of the
adjusting bolt (29e) with such structure, the relative horizonta1 rotating
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position of the rotor support base (1) to the adjustable surface plate (4) can
easily be adjusted, and such adjusted position can be maintained reliably.
~ ig. 10 and Fig. 11 show the mounting conditions of aforementioned
rotating position adjusting jig (29). In this mounting example, it is enough to
mount such jig (29) only at a position in the periphery of the adjustable
surface plates (4), (l~l). However, it is also possible to mount a plurality of
such jigs (29) including the other positions.
With such structure, the manner in which the support structure of the
present invention effect the horizontal levelling at the top of the hemi
spherical support mechanisms (2), (2') is hereinafter disclosed.
~ efore bridging the turbine rotor (A), the height of adjustable surface
plates (4), (4') on the base frames (3), (3'~ ade~uately placed on the floor
surface is adjusted with the adjusting bolts (l4), (14') as in the case of
existing support structure in order to obtain the horizontal levelling. When
such vertical adjustment is once completed, suitable wedges (not shown in the
figures) are driven into the clearances between thc adjustable surface plates
(4), (4') and the base ~rames (3), (3') in order to firmly and rigidly secure the
adjustable surface plates to the base frames. Thereafter, both ends (12) of
the shaft of the turbine rotor (A) are laid on the drive rollers (5), (5) and
follower rollers (5'), (5') of the roller support bases (1), (1') respectively.
If the floor surface may distort or warp due to the weight of turbine
rotor causing a poor levelling, such an error ~H in the horizontal levelling is
covered by the roller support bases (1), (1) which automatically follows a tilt
by means of the hemi spherical support mechanisms (2), (2') so long as such
error is not abnormally large, and the rollers (5), (5), (5'), (5') always support
perpendicularly to the axis C-C of the shaft of the turbine rotor ~A) even
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when the rotor shaft (12) may be distorted. (Refer to Fig. 12 and Fig. 13.)
Namely, the axis of the turbine rotor (A) and rollers (5), (5), (5'), (5') are
automatically ali~ned due to the weight of the turbine rotor (A). The same
situation is in effect for the lateral direction. Namely, as shown in Fig. I4,
even iE the axes Cl-Cl and C2-C2 of the rollers (5), (5') and (6), (6') are not
aligned slightly or mismatched to the axis C-C of the turbine rotor shaft
connecting the crests of the hemi spherical support mechanisms (2), (2'), it
can automatically be aligned to the axis C-C by the automatic axis adjusting
function of the hemi spherical support mechanisms (2), (2'). (Refer to Fig.
15.)
Therefore, even when the drive rollers (5), (5) are driven so as to rotate
the turbine rotor (A), it ro~ates on the same axis thereof and does not
generate any movement thereof in the axial direction, not followed by
frictional wearness of rollers (5), (5), (5'), (5') because both ends (12) of the
shaft of the turbine rotor is uniformly supported by the rollers (S), (5), (5'),
(5') by the surface contactness.
Furthermore, if the turbine rotor (A) moves even a little in the axial
direction while it is rotating, the rotor support bases (1), (1') can be rotated
horizontally around the shaft of the hemi spherical support mechanisms ~2),
(2') for the specified angle by moving forward or backward the adjusting bolts
(31), (31') in accordance with the direction and calculated amount of
movernent of the turbine rotor (A) and thereby the movement of the turbine
rotor (A) in the axial direction due to rotor drive can also be kept as small as
possible.
As described above, the support structure according to the present
invention can substantially and perfectly prevent movement of turbine rotor
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in the axial direction even during the rotation of the turbine rotor, does not
require the readjustment which has been essentially required by the existing
structure, can drastically reduce t~e time and labor necessary for the
horizontal levelling operation, and also can outstalldingly reduce frictional
wearness of support rollers.
