U.S. patent application number 10/857820 was filed with the patent office on 2005-12-01 for balance assembly for rotary turbine component and method for installing and/or adjusting balance weight.
Invention is credited to Altman, John Edward, Ceccopieri, Fernando, McGreehan, William Francis, Przytulski, James Charles, Shaub, Clarence J..
Application Number | 20050265846 10/857820 |
Document ID | / |
Family ID | 34941348 |
Filed Date | 2005-12-01 |
United States Patent
Application |
20050265846 |
Kind Code |
A1 |
Przytulski, James Charles ;
et al. |
December 1, 2005 |
Balance assembly for rotary turbine component and method for
installing and/or adjusting balance weight
Abstract
A balance assembly for turbine rotating components, such as
turbine rotors, as well as method for installing and/or adjusting
at least one balance weight in the balance assembly and turbine
section having this balance assembly and a radially extending
access pathway for accessing this balance assembly. The balance
assembly comprises; (a) a balance weight retention member having a
circumferential periphery and a slot formed therein along at least
a portion thereof, the slot having: (1) a bottom surface; (2) an
opening; and (3) a pair of spaced apart and opposed side walls
connecting the bottom surface and the opening, the side walls
sloping inwardly between the bottom surface and the opening to
define a balance weight engaging section; (b) at least one balance
weight configured and sized to be insertable through the opening of
the slot and to be positionable for movement within the slot and
having a pair of spaced apart generally inwardly sloping shoulder
surfaces capable of engaging the side walls of the slot at the
balance weight engaging section; and (c) a balance weight securing
member associated with the at least one balance weight that can be
actuated to: (1) move the at least one balance weight away from the
bottom surface so that the shoulder surfaces engage the side walls
at the balance weight engaging section such that the at least one
balance weight is in a secured position within the slot; or (2)
move the at least one balance weight towards the bottom surface so
that the shoulder surfaces do not engage the side walls at the
balance weight engaging section such that the at least one balance
weight is in a unsecured position within the slot.
Inventors: |
Przytulski, James Charles;
(Fairfield, OH) ; McGreehan, William Francis;
(Liberty Twp., OH) ; Altman, John Edward;
(Cincinnati, OH) ; Shaub, Clarence J.; (Lebanon,
OH) ; Ceccopieri, Fernando; (Loveland, OH) |
Correspondence
Address: |
JAGTIANI + GUTTAG
10363-A DEMOCRACY LANE
FAIRFAX
VA
22030
US
|
Family ID: |
34941348 |
Appl. No.: |
10/857820 |
Filed: |
June 1, 2004 |
Current U.S.
Class: |
416/144 |
Current CPC
Class: |
F16F 15/34 20130101;
F01D 5/027 20130101; F16F 15/322 20130101; F04D 29/662
20130101 |
Class at
Publication: |
416/144 |
International
Class: |
B63H 001/00 |
Claims
What is claimed is:
1. A balance assembly for a rotary turbine component, which
comprises: a. a generally annular balance weight retention member
having a circumferential periphery and a slot formed therein along
at least a portion thereof, the slot having: (1) a bottom surface;
(2) an opening spaced from the bottom surface; and (3) a pair of
spaced apart and opposed side walls connecting the bottom surface
and the opening, the side walls sloping inwardly between the bottom
surface and the opening to define a balance weight engaging
section; b. at least one balance weight being configured and sized
to be insertable through the opening of the slot and to be
positionable for movement within the slot and having a pair of
spaced apart generally inwardly sloping shoulder surfaces capable
of engaging the side walls of the slot at the balance weight
engaging section; and c. a balance weight securing member
associated with the at least one balance weight that can be
actuated to: (1) move the at least one balance weight away from the
bottom surface so that the shoulder surfaces engage the side walls
at the balance weight engaging section such that the at least one
balance weight is in a secured position within the slot; or (2)
move the at least one balance weight towards the bottom surface so
that the shoulder surfaces do not engage the side walls at the
balance weight engaging section such that the at least one balance
weight is in a unsecured and movable position within the slot.
2. The assembly of claim 1 wherein the slot has a generally
dovetail-shaped cross-section.
3. The assembly of claim 2 wherein the slot is formed in the
balance weight retention member along the entire circumferential
periphery thereof.
4. The assembly of claim 3 wherein the opening of the slot has a
substantially uniform width along the entire circumferential
periphery.
5. The assembly of claim 2 wherein the balance weight engaging
section of the slot has a generally trapezoidal shape.
6. The assembly of claim 1 wherein there are at least two balance
weights.
7. The assembly of claim 6 wherein there are a pair of balance
weights.
8. The assembly of claim 1 wherein the balance weight securing
member comprises a bolt having a threaded shaft and wherein the at
least one balance weight has a threaded portion for receiving the
threaded shaft that extends from the top to the bottom of the at
least one balance weight.
9. The assembly of claim 8 wherein the threaded shaft has a distal
end that projects outwardly away from the bottom of the at least
one balance weight when the bolt is turned in the secured position
direction and engages the bottom surface of the slot so that the at
least one balance weight is forced away from the bottom surface of
the slot and towards the side walls of the slot at the balance
weight engaging section thereof.
10. The assembly of claim 10 which further comprises a locking
member for preventing the bolt from being disconnected from the at
least one balance weight.
11. The assembly of claim 10 wherein the locking member comprises a
generally cylindrical bore formed in the distal end of the shaft
perpendicular to the longitudinal axis thereof and a locking pin
that is insertable into the bore.
12. A balance assembly for a rotary turbine component, which
comprises: a. a generally annular balance weight retention member
having a circumferential periphery and a slot formed therein along
at least a portion thereof, the slot having: (1) a bottom surface;
(2) an opening spaced from the bottom surface; and (3) a pair of
spaced apart and opposed side walls connecting the bottom surface
and the opening, and being configured to define: (a) a lower
section of the slot wherein the side walls extend generally
upwardly from the bottom surface; (b) an intermediate section of
the slot adjacent to the lower section and wherein the side walls
slope generally inwardly to form a constriction at the top of the
intermediate section; and (c) an upper section of the slot adjacent
to the intermediate section and wherein the side walls slope
generally outwardly from the constriction to the opening; b. at
least one balance weight being configured and sized to be
insertable through the opening and upper section of the slot and to
be positionable for movement within the slot and having: (1) a base
portion with a width smaller than the width defined by the lower
section of the slot so that the at least one balance weight is
movable within the slot; and (2) a shoulder portion connected to
the base portion and having a pair of spaced apart shoulder
surfaces sloping generally inwardly so as to be capable of engaging
the side walls at the intermediate section of the slot; and c. a
balance weight securing member associated with the at least one
balance weight that can be actuated to: (1) move the at least one
balance weight away from the bottom surface so that the shoulder
surfaces engage the side walls at the intermediate section such
that the at least one balance weight is in a secured position
within the slot; or (2) move the at least one balance weight
towards the bottom surface so that the shoulder surfaces do not
engage the side walls at the intermediate section such that the at
least one balance weight is in a unsecured and movable position
within the slot.
13. The assembly of claim 12 wherein the slot is formed in the
balance weight retention member along the entire circumferential
periphery thereof.
14. The assembly of claim 13 wherein the opening of the slot has a
substantially uniform width along the entire circumferential
periphery.
15. The assembly of claim 13 wherein the slot has a generally
dovetail-shaped cross-section.
16. The assembly of claim 15 wherein the upper section and
intermediate section of the slot each have a generally trapezoidal
shape and wherein the shoulder portion of the at least one balance
weight has a generally trapezoidal shape.
17. The assembly of claim 12 wherein the balance weight securing
member comprises a bolt having a threaded shaft and wherein the at
least one balance weight has a threaded portion for receiving the
threaded shaft that extends from the top to the bottom of the at
least one balance weight.
18. The assembly of claim 17 wherein the threaded shaft has a
distal end that projects outwardly away from the bottom surface of
the at least one balance weight when the bolt is turned in the
secured position direction and engages the bottom surface of the
slot so that the at least one balance weight is forced away from
the bottom surface of the slot and towards the side walls of the
slot at the intermediate section thereof.
19. The assembly of claim 10 which further comprises a generally
cylindrical bore formed in the distal end of the shaft
perpendicular to the longitudinal axis thereof and a locking pin
that is insertable into the bore.
20. The assembly of claim 12 wherein the at least one balance
weight further comprises a neck section adjacent to the shoulder
section that is sized and configured to be capable of fitting
within the constriction in the slot.
21. A method for installing at least one balance weight in a
balance assembly for a rotary turbine component, the balance
assembly comprising: (a) a generally annular balance weight
retention member having a circumferential periphery and a slot
formed therein along at least a portion thereof, the slot having a
bottom surface, an opening spaced from the bottom surface and a
pair of spaced apart and opposed side walls connecting the bottom
surface and the opening, the side walls sloping inwardly between
the bottom surface and the opening to define a balance weight
engaging section; (b) the at least one balance weight being
configured and sized to be insertable through the opening of the
slot and to be positionable for movement within the slot and having
a pair of spaced apart generally inwardly sloping shoulder surfaces
capable of engaging the side walls of the slot at the balance
weight engaging section, the method comprising the steps of: 1.
inserting the at least one balance weight through the opening of
the slot of the retention member so that the at least one balance
weight is in an inserted position within the slot; 2. adjusting the
at least one balance weight from the inserted position to a balance
weight securing member associating position within the slot so that
the at least one balance weight is capable of being associated with
the balance weight securing member; and 3. associating a balance
weight securing member with the at least one balance weight while
in the balance weight securing member associating position, the
balance weight securing member being capable of being actuated to:
(a) move the at least one balance weight away from the bottom
surface so that the shoulder surfaces engage the side walls at the
balance weight engaging section such that the at least one balance
weight is in a secured position within the slot; or (b) move the at
least one balance weight towards the bottom surface so that the
shoulder surfaces do not engage the side walls at the balance
weight engaging section such that the at least one balance weight
is in a unsecured position within the slot.
22. The method of claim 21 which comprises the further step of
associating with the balance weight securing member a locking
member that prevents the balance weight securing member from being
disassociated from the at least one balance weight.
23. The method of claim 21 wherein at least two balance weights are
inserted into the slot.
24. The method of claim 23 wherein a pair of balance weights are
inserted into the slot.
25. The method of claim 23 wherein the slot is formed in the
balance weight retention member along the entire circumferential
periphery thereof and wherein the opening of the slot has a
substantially uniform width along the entire circumferential
periphery.
26. The method of claim 25 which comprises the further step of
moving the inserted balance weights in the slot until positioned
approximately equally spaced from each other.
27. The method of claim 21 wherein the rotary turbine component is
a rotor positioned within a turbine engine section having a
radially extending access pathway for accessing the balance
assembly.
28. The method of claim 27 for subsequent balancing of the rotor
after insertion of the at least one balance weight and positioning
thereof at a first position within the slot, and after the rotor is
operated such that balancing thereof is needed, the method
comprising the further steps of: (4) rotating the rotor such that
the at least one balance weight is accessible through the access
pathway; and (5) moving the at least one balance weight to a second
position within the slot to achieve subsequent balancing of the
rotor.
29. The method of claim 27 wherein the at least one balance weight
is inserted within the slot before the retention member is secured
to the rotor.
30. A turbine engine section having a balance assembly for a rotary
turbine component positioned in the turbine section and a radially
extending access pathway for accessing the balance assembly for
adjusting the position of at least one balance weight within a slot
of a balance weight retention member in the balance assembly, the
balance assembly comprising: a. a generally annular balance weight
retention member having a circumferential periphery and a generally
dovetail-shaped slot formed therein along the entire length
thereof, the slot having: (1) a bottom surface; (2) an opening
spaced from the bottom surface; and (3) a pair of spaced apart and
opposed side walls connecting the bottom surface and the opening,
the side walls sloping inwardly at a section of the slot between
the bottom surface and the opening; b. at least one balance weight
being configured and sized to be movable within the slot and having
a pair of spaced apart shoulder surfaces sloping generally inwardly
so as to be capable of engaging the side walls of the slot at the
balance weight engaging section; c. a balance weight securing
member associated with the at least one balance weight that can be
actuated to: (1) move the at least one balance weight away from the
bottom surface so that the shoulder surfaces engage the side walls
at the balance weight engaging section of the slot such that the at
least one balance weight is in a secured position within the slot;
or (2) move the at least one balance weight towards the bottom
surface so that the shoulder surfaces do not engage the side walls
at the balance weight engaging section of the slot such that the at
least one balance weight is in an unsecured position within the
slot.
31. The turbine section of claim 30 wherein the slot is formed in
the balance weight retention member along the entire
circumferential periphery thereof.
32. The turbine section of claim 31 wherein there are at least two
balance weights.
33. The turbine section of claim 32 wherein there are a pair of
balance weights.
34. The turbine section of claim 30 wherein the balance weight
securing member comprises a bolt having a threaded shaft and
wherein the at least one balance weight has a threaded portion for
receiving the threaded shaft that extends from the top to the
bottom of the at least one balance weight.
35. The turbine section of claim 30 wherein the rotary turbine
component is a rotor positioned within the turbine section and
wherein the at least one balance weight is inserted within the slot
before the retention member is secured to the rotor.
36. The turbine section of claim 30 wherein the balance weight
engaging section of the slot has generally trapezoidal shape.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to a balance assembly for a
rotary turbine component such as a turbine rotor. This invention
also relates to a method for installing one or more balance weights
in this balance assembly, as well as adjusting the balance
weight(s) after installation. This invention further relates to a
turbine section having this balance assembly and a radially
extending access pathway for accessing this balance assembly.
[0002] In the production of turbine engines, the balancing of the
rotary turbine components, such as turbine rotors, can be an
essential and important step. The turbine rotors are typically
balanced initially prior to the actual assembly of the engine. This
balancing can be achieved in variety of ways, for example, by the
attachment of special weights designed to fit on bolts or within
grooves of the rotor or associated components, or by grinding
material from specified sections on the rotor. See U.S. Pat. No.
4,220,055 (Dubois et al), issued Sep. 2, 1980 (balance weight
having beak engaging groove of collar and secured to rotor by
rivet); U.S. Pat. No. 4,803,893 (Bachinski), issued Feb. 14, 1989
(balance weights located in groove of cover plate for rotor
assembly); commonly assigned U.S. Pat. No. 5,011,374 (Miller),
issued Apr. 30, 1991 (balance clips attached to shroud of rotor);
commonly assigned U.S. Pat. No. 5,018,943 (Corsmeier et al), issued
May 28, 1991 (balance weight mounted in dovetail slots formed in
circumference of rotor disk and bottom of dovetail root of rotor
blades inserted within dovetail slots). Due to subsequent
operations in assembling the engine, there is often a need for
further adjustment or balancing of the rotary components after this
engine is completed. This is commonly referred to as "trim
balancing." During subsequent operation of the turbine engine,
adjustment or rebalancing of the rotary components can also be
necessary.
[0003] A problem with certain balancing systems for rotors is that
trim balancing or rebalancing of the rotors can require partial or
complete disassembly of the engine in order to access the balance
weights. For example, one prior balancing system uses balance
weights that are inserted into a circular or circumferential groove
or slot typically formed in the face or circumference of the disk,
wheel and/or spacer of the rotor, with the weights then being moved
or adjusted within the groove or slot to achieve the desired degree
of balancing. See commonly assigned U.S. Pat. No. 3,736,811
(Neary), issued Jun. 5, 1973 (balance weight inserted in balance
groove formed in face of turbine wheel and locked in place anywhere
along balance groove by screw adjustment); U.S. Pat. No. 4,842,485
(Barber), issued Jun. 27, 1989 (circular groove formed in at least
one face of turbine to receive weight assembly comprising arcuate
body member with bore and slots in side walls to allow expansion by
expander screw); commonly assigned U.S. Pat. No. 6,481,969 (Berry
et al), issued Nov. 19, 2002 (dovetail-shaped grooves formed in
axial faces and circumferential rims of wheels and spacers of rotor
body and complementary-shaped balance weights inserted through
entry apertures in grooves and circumferentially aligned into
adjusted positions). After the balance weights are secured in place
in the groove or slot, and the engine is completely assembled,
these balance weights are typically intended to be fixed in
position and not moved again to readjust or trim the balance of the
rotary component. As a result, these balance weights are usually
inaccessible without at least partial disassembly of the engine.
Certain of these balance weight systems also require specially
formed access ports or openings in the groove or slot so that the
balance weights can be inserted. See FIGS. 1 and 2 of U.S. Pat. No.
3,736,811 (prior art) and FIG. 5 of U.S. Pat. No. 6,481,969. Such
access ports or openings can cause a lack of symmetry in weight
distribution of the balance assembly, as well as creating potential
weaknesses in the balance assembly with regard to the concentration
of stresses.
[0004] Balance systems for rotary components of turbine engines
have also been developed that allow for remote access to areas of
the engine where the balance weights are already installed, or
where the balance weights can be inserted, for trim balancing or
rebalancing without disassembly of the engine. Some of these
balance systems can require that the balance weight be inserted at
a specific location, thus making finer balance adjustments more
difficult to achieve. See U.S. Pat. No. 2,964,972 (Lindsey et al),
issued Dec. 20, 1960 (balance assembly for rotor comprising annular
member provided with plurality of circumferentially spaced thread
holes that can be accessed through pathway to receive balance
weights delivered by special tool); U.S. Pat. No. 5,545,010
(Cederwall et al), issued Aug. 13, 1996 (trim balancing of turbine
rotor by adding or removing balance weights or plugs through
compressor air flow path and pair of holes). Some of these remote
access balancing systems allow for insertion of the balance weight
at various positions in a groove or slot formed in the rotor
assembly. See U.S. Pat. No. 4,064,762 (Wilkner), issued Dec. 27,
1977 (tool for inserting balance weight into dovetail groove in
rotor disk); commonly assigned U.S. Pat. No. 6,279,420 (Knorowski
et al), issued Aug. 28, 2001 (balance weight groove formed in
rotor, a balance weight having a threaded opening for receiving a
screw and a threaded tool for inserting the balance weight in the
groove, rotating the screw to lock the balance weight in the
groove, and a staking tool that is inserted to stake the balance
weight and rotor, as well as the screw and balance weight).
However, after the balance weight is inserted into the groove, it
is, again, typically intended to be fixed in place and not moved
again to readjust or trim the balance of the rotary component.
[0005] Accordingly, it would be desirable to provide a balance
assembly for rotary turbine components, such as turbine rotors,
that can be used to trim balance or rebalance the rotor while the
turbine engine remains completely or substantially completely
assembled. It would also be desirable to provide a balance assembly
for turbine rotors where the balance weights can be relatively
easily located or moved to different positions to allow for
relatively fine adjustments of the balancing of the rotor. It would
also be desirable to be able to install the balance weights without
the need of specially formed access ports or openings in the
balance assembly. It would be further desirable to provide a
balance assembly for turbine rotors where the balance weights can
be relatively easily readjusted after initial installation for
subsequent trim balancing and rebalancing of the rotor.
BRIEF DESCRIPTION OF THE INVENTION
[0006] An embodiment of this invention relates to a balance
assembly for rotary turbine components, such as turbine rotors.
This assembly comprises:
[0007] a. a generally annular balance weight retention member
having a circumferential periphery and a slot formed therein along
at least a portion thereof, the slot having:
[0008] (1) a bottom surface;
[0009] (2) an opening spaced from the bottom surface; and
[0010] (3) a pair of spaced apart and opposed side walls connecting
the bottom surface and the opening, the side walls sloping inwardly
between the bottom surface and the opening to define a balance
weight engaging section;
[0011] b. at least one balance weight being configured and sized to
be insertable through the opening of the slot and to be
positionable for movement within the slot and having a pair of
spaced apart generally inwardly sloping shoulder surfaces capable
of engaging the side walls of the slot at the balance weight
engaging section; and
[0012] c. a balance weight securing member associated with the at
least one balance weight that can be actuated to:
[0013] (1) move the at least one balance weight away from the
bottom surface so that the shoulder surfaces engage the side walls
at the balance weight engaging section such that the at least one
balance weight is in a secured position within the slot; or
[0014] (2) move the at least one balance weight towards the bottom
surface so that the shoulder surfaces do not engage the side walls
at the balance weight engaging section such that the at least one
balance weight is in a unsecured position within the slot.
[0015] Another embodiment of this invention relates to a method for
installing at least one balance weight in this balance assembly.
This method comprises the steps of:
[0016] 11. inserting the at least one balance weight through the
opening of the slot of the balance weight retention member so that
the at least one balance weight is in a first inserted position
within the slot;
[0017] 2. adjusting the at least one balance weight from the first
inserted position to a second securing member associating position
within the slot so that the at least one balance weight is capable
of being associated with the balance weight securing member;
and
[0018] 3. associating the balance weight securing member with the
at least one balance weight while in the second position.
[0019] Another embodiment of this invention relates to a section of
a turbine engine having this balance assembly and a radially
extending access pathway for accessing this balance assembly.
[0020] The balance assembly and method of this invention, as well
as the section of the turbine engine having the radially extending
access pathway for accessing this balance assembly, provides a
number of significant benefits and advantages in the balancing of
rotary turbine components such as turbine rotors. The balance
assembly, method and section of the turbine engine having the
radially extending access pathway for accessing the balance
assembly of this invention allows the rotary turbine components to
be trim balanced or rebalanced while the turbine engine remains
completely or substantially completely assembled. The balance
assembly, method and section of the turbine engine having the
radially extending access pathway for accessing the balance
assembly of this invention allows the balance weight(s) to be
located or moved to different positions in the balance assembly to
allow for relatively fine adjustment in the balancing of the rotor.
The balance weight(s) and associated slot of the balance weight
retention member are also sized and configured such that specially
formed balance weight access ports or openings are not required for
insertion of the balance weight(s) into the slot. The balance
assembly and section of the turbine engine having the radially
extending access pathway for accessing this balance assembly of
this invention also allow for relatively easy readjustment of the
balance weight(s) after insertion into the slot for subsequent trim
balancing and rebalancing of the rotor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a fragmentary cross-section of a section of a
turbine engine showing an embodiment of the balance assembly of
this invention with an installed balance weight.
[0022] FIG. 2 is an enlarged sectional view of the balance assembly
of FIG. 1.
[0023] FIG. 3 is a view similar to FIG. 2 showing the insertion of
a balance weight in the slot of the balance weight retention
member.
[0024] FIG. 4 is a view similar to FIG. 3 showing the inserted
balance weight moved, adjusted or rotated from the initial inserted
position to a second position where the balance weight can be
associated with the balance weight securing member.
[0025] FIG. 5 is a view similar to FIG. 1 showing an access way in
a section of a turbine engine for accessing the balance assembly,
as well as a tool inserted through this access way for unsecuring,
moving and/or securing the balance weight.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring to the drawings, FIG. 1 illustrates a fragmentary
cross-section of a representative section of a turbine engine that
is indicated generally as 10 in which the balance assembly of this
invention can be used. Turbine engine section 10 is shown as having
a turbine rotor indicated generally as 14. Turbine engine section
10 can be any section having such a rotor 14, including but not
limited to a high pressure (HP) compressor section, a low pressure
(LP) compressor section, an HP turbine section, a LP turbine
section, an intermediate power (IP) turbine section, or a power
(PW) turbine section. In other words, the turbine engine section 10
shown in FIG. 1, and as described hereafter, should be considered
only representative of the use of the embodiment of the balance
assembly of this invention.
[0027] As shown in FIG. 1, rotor 14 comprises a plurality of
circumferentially spaced turbine blades, one of which is indicated
as 18, that extend radially from a central hub or disk indicated as
22. The root 24 of blade 18 is positioned between a blade retainer
26 and interstage seal 28 that together are secured to disk 22 by a
bolt assembly indicated generally as 30. As shown in FIG. 1,
turbine engine section 10 also includes a support structure
indicated generally as 34 for the stationary portion 38 of a
pressure seal. The pressure seal also includes a rotating portion
42 that is secured to a rotating shaft 46 by a bolt assembly
indicated generally as 50. Bolt assembly 50 also secures rotating
pressure seal portion 42 and shaft 46 to the rearward annular
portion 54 of disk 22.
[0028] As shown in FIG. 1, an embodiment of the balance assembly of
this invention indicated generally as 58 is used to balance rotor
14. This balance assembly 58 includes a balance weight retention
member indicated generally as 62, at least one balance weight
indicated generally as 66 and a balance weight securing member in
the form of a threaded bolt indicated generally as 70. The balance
weight retention member 62 includes a support portion 74 typically
having a concentric rabbet formed therein for securing or attaching
member 62 to the concentric outer surface 78 of rearward portion 54
of disk 22. To prevent rotation of balance weight retention member
62 around or about the concentric outer surface 78 of rearward
portion 54, support portion 74 can be provided with a slot (not
shown) that receives the head of a spring pin (not shown) that is
secured to the rearward portion 54 of disk 22.
[0029] As shown more particularly in FIG. 2, balance weight
retention member 62 also includes a generally annular balance
weight retention portion 86. Balance weight retention portion 86 is
provided with a slot 90 that is formed along at least a portion of
the circumferential periphery 92 of retention portion 86, and is
more typically formed along the entire length of periphery 92. As
shown in FIG. 2, slot 90 typically has a generally dove-tail shaped
cross sectional configuration. Slot 90 has a bottom surface
indicated as 94, an opening spaced from bottom surface 94 indicated
generally as 98 at the top of slot 90, and a pair of spaced apart
and opposed side walls indicated as 102 and 106 connecting the
bottom surface 94 to opening 98.
[0030] As shown in FIG. 2, side walls 102, 106 are shaped or
configured to define a generally rectangular-shaped lower section
110 of slot 90 where side walls 102, 106 extend generally upwardly
and perpendicularly from the respective ends of bottom surface 94,
an intermediate generally trapezoidal or wedge-shaped section 114
of slot 90 adjacent to lower section 110 where side walls 102, 106
generally converge or slope inwardly from the top of lower section
110 to form a constriction indicated as 118 at the top of
intermediate section 114, and an upper generally trapezoidal or
wedge-shaped section 120 of slot 90 adjacent to intermediate
section 114 and generally diverging or sloping outwardly from
constriction 118 to opening 98. At least upper and intermediate
sections 120 and 114 of slot 90, and also usually lower section 110
of slot 90, typically have substantially the same cross-sectional
configuration and width dimensions along the entire circumferential
length of slot 90. In particular, the width between the spaced
apart pair edges 122 and 124 of opening 98 is typically
substantially uniform or essentially the same along the entire
length of slot 90, e.g., along the entire circumferential periphery
92.
[0031] As shown in FIG. 2, balance weight 66 includes a base
portion indicated generally as 126 having a generally planar bottom
surface 130, a pair of spaced apart outwardly diverging or sloping
generally planar surfaces 132 and 136 connected at each end of
bottom surface 130, and a pair of spaced apart upwardly extending
generally planar surfaces 140 and 144 connected at the respective
ends of outwardly sloping surfaces 132, 136. As shown in FIG. 2,
balance weight 66 also includes a generally trapezoidal or
wedge-shaped shoulder portion indicated generally as 148 adjacent
to base portion and having a pair of spaced apart generally
inwardly converging or sloping shoulder surfaces 152 and 156
connected at the respective ends of upwardly extending surfaces 140
and 144. As also shown in FIG. 2, balance weight 66 further
includes a generally rectangular-shaped neck portion indicated
generally as 160 adjacent to shoulder portion 148 and having a pair
of spaced apart generally planar upwardly extending neck surfaces
164 and 168 connected at the respective ends to shoulder surfaces
152, 156 and a generally planar top surface 172 connected at the
respective ends to neck surfaces 164, 168. As shown in FIG. 2, top
surface 172 is typically substantially parallel to bottom surface
130.
[0032] As shown in FIG. 2, bolt 70 has a head 176 connected to a
threaded generally cylindrical shaft 180 having a distal end
indicated generally as 184. As shown in FIG. 2, balance weight 66
has a complementary threaded portion for receiving threaded shaft
180 in the form of a threaded cylindrical insert 188 positioned
within a generally cylindrical bore 192 that extends from the top
surface 172 to the bottom surface 130 of balance weight 66. As
shown in FIG. 2, balance weight 66 is typically substantially
symmetrical about the centerline defined by cylindrical insert 188.
As shown in FIG. 2, bolt 70 is also provided with a locking member
in the form of locking pin 196 that is inserted through a generally
cylindrical bore 200 formed in distal end 184 perpendicular to the
longitudinal axis of shaft 180. When inserted into bore 200,
locking pin 196 prevents bolt 70 from accidentally being completely
disconnected from balance weight 66 as bolt 70 is unscrewed.
[0033] Balance weight 66 is shown in FIGS. 1 and 2 as being in a
secured position within slot 90 such that balance weight 66 cannot
be moved within slot 90. This is achieved by turning or screwing
bolt 70 into insert 188 in the "secure position" direction such
that the distal end 184 of shaft 180 projects further outwardly
away from the bottom surface 130 of balance weight 66 and towards
bottom surface 94 of slot 90. As bolt 70 is screwed further into
insert 188 so that distal end 180 continues to project further
outwardly from bottom surface 130, distal end 180 eventually
engages bottom surface 94 so that balance weight 66 is forced away
from bottom surface 94. As a result, shoulder surfaces 152, 156 of
balance weight 66 are moved towards side walls 102, 106 where they
slope inwardly at intermediate section 114 of slot 90. As balance
weight 66 moves further away from bottom surface 94 of slot 90,
neck portion 160 will eventually be guided through constriction 118
and into the upper section 122 of slot 90. Eventually, shoulder
surfaces 152, 156 will engage respective side walls 102, 106 at
intermediate (i.e., "balance weight engaging") section 114 until
bolt 70 can no longer be screwed into insert 188 of balance weight
66. As this point, balance weight 66 is held in a place in a
secured and relatively immovable position due to the force of
distal end 180 of shaft 174 against bottom surface 94 of slot 90
and the frictional engagement of shoulder portions 152, 156 against
respective side walls 102, 106 at the intermediate (i.e., "balance
weight engaging") section 114 of slot 90. As also shown in FIG. 2,
when balance weight 66 is in this secured position, bottom surface
130 of balance weight 66 is typically substantially parallel to
bottom surface 94 of slot 90.
[0034] In order to install or position balance weight 66 within
slot 90, bolt 70 is initially not attached or associated with
balance weight 66. Instead, as shown in FIG. 3, balance weight 66
is inserted through opening 98 and upper section 122 of slot 90
without being associated with bolt 70. Insertion of balance weight
66 within slot 90 is typically carried out before balance weight
retention member 62 is secured to rearward portion 54 of disk 22.
As shown in FIG. 3, balance weight 66 is typically inserted through
opening 98 and upper section 122 at a slanted angle, i.e., such
that bottom surface 130 of balance weight 66 is not perpendicular
to bottom surface 94 of slot 90. Because the width or dimension of
balance weight 66 defined by top surface 172 and bottom surface 130
is less than the width defined by constriction 118, as well as the
width defined by and between outwardly sloping surface 204 (or 206)
of slot 90 at upper section 122 and inwardly sloping surface 208
(or 210) of slot 90 at intermediate section 114, balance weight 66
can be inserted into slot 90 without the need of specially
configured access ports or openings. Indeed, balance weight 66 can
typically be inserted through opening 98 and upper section 122 of
slot 90 at any position along the length thereof, e.g. along
circumferential periphery 92.
[0035] From this first inserted position indicated generally as 212
in FIG. 3, and because of the configuration and size of balance
weight 66, as well as the configuration and size of slot 90 at
intermediate and lower sections 114 and 110, balance weight 66 can
then be moved, adjusted or rotated to a second position indicated
generally as 216 in FIG. 4 within lower section 110 of slot 90.
When in second position 216, balance weight 66 is fully within and
movable in slot 90 (e.g., within lower section 110) and is also
capable of receiving bolt 70. When bolt 70 is screwed into insert
188 in balance weight 66 such that bore 200 is beyond bottom
surface 130, locking pin 196 can then be inserted into bore 200 to
prevent bolt 70 from being accidentally disassociated or
disconnected from balance weight 66 when bolt 70 is unscrewed.
[0036] FIG. 5 shows turbine engine section 10 with a portion of the
supporting structure indicated generally as 300 having formed
therein respective outer and inner access holes 304 and 308 to
provide a radially extending pathway indicated generally as 312 for
access to balance assembly 58. As shown in FIG. 5, a tool indicated
generally as 316 is provided with an elongated shaft 320 that is
inserted into pathway 312. Attached at the distal end of shaft 320
is a bolt driver section 324 that is configured or shaped for
insertion into the inner driven section 328 of bolt head 176.
Typically, bolt drive section 324 and driven section 328 have
complementary hexagonal, square or other shaped cross-sections. By
rotating or turning shaft 320 in the desired direction, bolt 70 can
be screwed or unscrewed in a direction that will cause balance
weight 66 to be either moved away from bottom surface 94 of slot 90
such that balance weight 66 is in a secured position, or towards
bottom surface 94 such that balance weight 66 is in unsecured
position. When balance weight 66 is in an unsecured position, it
can then be moved anywhere along the circumferential length of slot
90 (e.g., within lower section 110) to any desired balancing
position by simply rotating rotor 14 while tool 316 is in use. When
balance weight 66 has reached the desired position, it can then
secured within slot 90 as previously described.
[0037] While FIGS. 1-5 show only one balance weight 66, it should
be understood that typically more than one balance weight 66 is
inserted, positioned or present within slot 90. Indeed, typically a
pair of balance weights 66 are inserted, positioned or present
within slot 90. During initially balancing of rotor 14, the pair of
balance weights 66 are typically moved within slot 90 such that
they are approximately 180.degree. opposite each other. As balance
assembly 58 requires adjustment to trim balance or rebalance rotor
14, the balance weights 66 can be moved to different positions
within slot 90 to achieve the desired degree of balancing. If three
balance weights 66 are inserted within slot 90, they are typically
moved initially within slot 90 to provide approximately 120.degree.
spacing (i.e., approximately equal spacing) from each other, and so
on in like fashion or manner where more than three balance weights
are inserted.
[0038] After the balance weight(s) 66 are inserted and initially
positioned within slot 90, the positioning of balance weight(s) 66
within slot 90 can be adjusted as needed or desired to balance
rotor 14. For example, the positioning of balance weight(s) 66 can
be adjusted after the initial operation of rotor 14 to provide
subsequent or further balancing thereof, e.g., trim balancing.
Access to balance weight(s) 66 to carrying out such subsequent or
further balancing of rotor 14 is typically achieved by rotating or
turning rotor 14 so that each respective balance weight 66 whose
position needs to be adjusted is accessible by tool 316 via pathway
312. The position of the accessed balance weight 66 can then be
adjusted with slot 90 as needed.
[0039] While specific embodiments of this invention have been
described, it will be apparent to those skilled in the art that
various modifications thereto can be made without departing from
the spirit and scope of this invention as defined in the appended
claims.
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