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Патент USA US3042379

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July 3, 1962
H. w. WELSH
3,042,369
PINNED BLADE SEALING MEANS
Filed Feb. 11, 1959
INVENTOR.
ATTORNEY
United States Patent 0
3,042,369
Patented July 3, 1962‘
1
2
3,042,369
platforms do not constitute a seal, any openings or clear
ances large enough to bleed air therethrough, such as the
PINNED BLADE SEALING MEANS
opening 48 between adjacent blade tangs and platforms
Harvey W. Welsh, Indianapolis, Ind., assignor to General
Motors Corporation, Detroit, Mich., a corporation of
and rotor rim, as well as clearances 44 and 45, will permit
a reverse circulation of the gas or air from its normal
path because of the differential in pressures of the air on
opposite sides of the platforms. This reverse circulation
of air causes a loss of compression resulting in lower
compressor e?‘iciency. Accordingly, a gas seal constitut
This invention relates to a gas seal and vibration damp
10 ing the subject of this invention is inserted between the
ing means.
More particularly, this invention relates to a gas seal
rotor rim and blade tangs are shown in FIGURE 2. The
and vibration damping means for use in combination with
seal comprises a thin (.005”—.010" thick, for example)
a rotor and blade assembly wherein each of the blades
annular sheet metal plate 32 having a continuous inner
is secured to the rotor by a pin, and an annular seal
rim 34, an outer stepped rim 36, and a plurality of cir
Delaware
Filed Feb. 11, 1959, Ser. No. 792,664
3 Claims. (Cl. 253-77)
member is mounted between the rotor and blades on 15 cumferentially spaced holes 38 aligned with the holes 24
and 26 in the tangs and rotor rim. The outer rim 36
the pins to control the circulation of gas from the down
stream to the upstream side of the assembly.
Therefore, it is an object of this invention to provide
has radially projecting circumferentially spaced portions
lation of gas from one portion of the assembly to another,
and to dampen the blade vibration.
Other features, advantages and objects will become ap
parent by reference to the detailed description of the
invention and to the drawings wherein there is shown 25
forms. The space between projections 50 therefore pro
vides recesses 52 of a circumferential length equal to
the circumferential length of the stalk portions of each
blade assembly. The seal 32 is inserted between the
rotor rim 22 and the downstream tang 20 extending
radially into close adjacency with the bottom of groove 42
50 of a circumferential length equal to the distance
a gas seal and vibration damping means in combination
between blade tangs of adjacent blades, i.e., equal to the
with a pinned rotor blade assembly to control the circu 20 length of the combined overhang of adjacent blade plat
the preferred embodiments of this invention.
In the drawings:
FIGURE 1 is a front elevational view with parts broken
away and sectioned of a portion of a rotor assembly em
as seen best in FIGURE 2 and the underside of the blade
platforms 18 as seen best in FIGURE 1, effectively pre
venting the reverse ?ow of air from the downstream to
30 the upstream portions of the blade assembly.
A nomi
nal radial clearance is provided between the bottom of
the groove and the underside of the platforms with respect
sembly of FIGURE 1 on a plane indicated by the lines
to the periphery of the seal to permit a slight relative
2-2 of FIGURE 1, and
roation between the parts, this clearance being sufficient
FIGURE 3 is a front elevational view of a detail of
35 to prevent an interference ?t while, however, maintaining
FIGURE 1.
a good seal.
Referring now to the drawings and more particularly to
In addition to controlling the circulation of air, plate
FIGURE 1, there is shown therein a portion of a rotor
bodying this invention,
FIGURE 2 is a cross-sectional view of the rotor as
32 also constitutes a vibration damping means. In a
assembly 10 of an axial ?ow type compressor, the rotor
assembly including a rotor or disk 12 having a plurality 40 pinned blade connection of this kind, it frequently oc
of circumferentially spaced blades 14 secured thereto.
Each of the blades includes a platform 18 integral there
curs that the blades are tuned to an exciting engine
order of vibration, which can result in damage to the
engine at certain predetermined speeds. The seal 32,
however, in the position indicated, constitutes a dry fric
the tangs being slightly greater than the thickness of the 45 tion damper to dampen these undesirable vibrational
frequencies and therefore permit operation of the engine
rim portion 22 of the rotor 12 with which they are
at speeds otherwise unobtainable, i.e., the range of ob
adaped to cooperate. As seen in FIGURE 2, the tangs
jectionable vibrations is raised therefore raising the per
29 have holes 24 axially aligned with each other and
missible safe engine speed. Since the reaction loads on
adapted to be aligned with holes 26 in the rim 22 of the
rotor for the insertion therethrough of pins 28 to secure 50 the assembly tends to push the assembly upstream, the
with, the platform having two tangs 20 depending there
from to de?ne a blade stalk, the axial distance between
the blades to the rotor upon straddling of the rotor rim
seal is inserted between the downstream tangs and the
rim so that the tangs and seal are pressed against the rim
22 by the tangs 20. Axial displacement of the pins is
permitting the seal to effectively dampen the objectionable
prevented by the abutment of head 29 and nuts or other
vibrations. The seal therefore acts as a bearing surface
retainers 30' against the tangs.
As shown more speci?cally in FIGURE 1, the blade 55 upon relative movement of the tangs with respect to the
platforms 18 have edges 40 extending circumferentially
rim, i.e., the upstream faces of the tangs and the down
stream face of the rim rub against the opposite faces of
beyond the tangs 20 into close proximity to each other
upon assembly to the rotor, a nominal circumferential
the seal as they pivot about each other due: to the cen
rifugal and gas bending forces acting on the blades. The
clearance being provided therebetween. Each of the
grooves 42 between the blade tangs extends radially out 60 tendency of the assembly to be moved upstream because
of the reaction loads also maintains the clearance be
ward a distance suf?cient to provide a small clearance
tween the upstream tangs and the rim for the relative
44 between the periphery of the rotor rim 22 and the
rotation between the rim and tangs.
base 43 of the groove together with the clearance be
tween adjacent platforms permitting a slight relative
While the invention is believed to be clear from an in
rotation between the blade and rotor on the pin 28 under 65 spection of the drawings, a brief description of the as
the in?uences of the gas bending and centrifugal forces
sembly thereof is as follows. The seal 32 is abutted
acting on the blades. Slight axial clearances or spaces
against the rotor rim 22 with the holes 26 and 38 axially
45 are also provided between the rotor rim 22 and the
aligned. Each of the blades with its depending tangs 20
blade tangs.
is then slipped over the seal and rim with the stalks
Since a pressure rise is effected from the upstream edge 70 ?tting in the slots or recesses 52 and the underside of
46 as seen in FIGURE 2 to the downstream edge 47 of
the platform edges 40‘ cooperating with the projections
the compressor, and since the substantially abutting blade
50. Pins 28 are then inserted through the axially aligned
3,042,369
3
mounting each of said blade tangs in overlapping rela
tionship to the rim of said rotor, each of said platforms
extending circumferentially beyond said stalks and tangs
and substantially abutting adjacent platforms, the mount
holes and secured against axial displacement. The as
sembly is then complete, and the seal effectively prevents
reverse circulation of air from the downstream to the
upstream side and dampens the vibrations imposed on
the blade assemblies.
While the invention has been described in its preferred
form for use in an axial flow type compressor, it will be
ing of said blade tangs on said rotor providing openings
between said rotor rim and blade stalks through which
?uid may pass, the construction and arrangement of said
platforms and tangs de?ning other openings between the
clear to those skilled in the art that many modi?cations
rotor rim and adjacent tangs and the undersides of said
can be made thereto without departing from the scope
10 platforms through which ?uid may also pass, and a
of the invention.
combined vibration damping and ?uid seal member mount
ed on all said pin means against said rotor and tangs
I claim:
1. A rotor assembly comprising a rotor, a plurality of
blades pivotally secured to and circumferentially spaced
between said tangs and rotor and extending radially into
around the outer rim of said rotor, said blades each hav
substantially abutting relationship to said platforms and
ing a tang depending from a platform, pin means piv 15 stalks to cover all said openings, said member damping
blade vibrations and blocking the ?ow of ?uid through said
otally mounting each of said blade tangs in overlapping re
openings.
lationship to the rim of said rotor, each of said platforms
3. A rotor assembly as in claim 2, wherein said member
extending circumferentially beyond said tangs and sub
comprises a flat disc having a circumferentially slotted
stantially abutting adjacent platforms, the construction and
outer rim providing spaced radial projections of a cir
arrangement of said platforms and tangs de?ning openings
cumferential length and radial extent su?icient to cover
between the rotor rim and adjacent tangs and the under
said other openings, the portions of said disc between
sides of said platforms through which ?uid may pass, and
said projections blocking said ?rst-mentioned openings.
a combined vibration damping and ?uid seal member
mounted on all said pin means against said rotor and
References Cited in the ?le of this patent
FOREIGN PATENTS
tangs between said tangs and rotor and extending radially
into substantially abutting relationship to said platforms
covering said openings, said member damping blade vibra
tions and blocking the ?ow of ?uid through said openings.
2‘. A rotor assembly comprising a rotor, a plurality of
blades pivotally secured to and circumferentially spaced
around the outer rim of said rotor, said blades each
having a stalk depending from a platform and a blade
tang depending from said stalk, pin means pivotally
202,528
30
701,263
724,281
745,073
777,612
1,097,487
1,136,390
Australia ____________ __ July 13, 1956
Great
Great
Great
Great
Britain
Britain
Britain
Britain
________ __ Dec.
________ __ ‘Feb.
_________ __ Feb.
________ __ June
23,
16‘,
22,
26,
France ______________ __ Feb. 16,
France ______________ __ Dec. 29,
1953
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