Blade vibration damping pins for turbomachiner

Hanson, M. P.

English

NASA Technical Reports Server

REPLY TO 
ATTN OF: G P  
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
WASHINGTON, D.C. 20546 
June 30, 1971 
MEMORANDUM 
/. TO : KSI/Scientific & Technical Information Division ,- w
A t t n :  M i s s  Winnie M. Morgan 
FROM : GP/Office of Ass i s t an t  General 
Counsel fo r  Patent Matters 
SUBJECT: Announcement of NASA-Owned 
U.S. Pa t en t s  i n  STAR 
I n  accordance with the  procedures contained i n  the  Code G P  
t o  code US1 memorandum on t h i s  subject,  dated June 8, 1970, 
the attached NASA-owned U.S .  patent is being forwarded fo r  
abstract ing and announcement i n  NASA STAR. 
The following information is provided : 
U.S.  Patent No.  2,997,274 
Corporate Source L e w i s  Research Center 
Supplementary 
Corporate Source 
NASA Patent  C a s e  No .  : XLE-00155 , 
Gayke Parker 
Enclosure : 
Copy of Patent  
https://ntrs.nasa.gov/search.jsp?R=19710019678 2020-03-17T03:11:42+00:00Z
Aug. 22, 1961 M. P. HANSON 2,997,274 
T'JREO-MACHINE BLADE VIBRATION DAMPER 
Filed April 13, 1953 
t 
INVENTOR 
2,997,274 $Ice Patented Aug. 22, 1961 
1 2 
and clearances between blade shank 14 and rotor disc 10 
are exaggerated, the pin 20 will exert a continuous, calcu- 
latable force against appendage 24 and in the event of 
vibration, the bending of blade 12 causes relative motion 
United States Of America as 6 between the appendage 24, pin 20 and rotor disc 10. The 
frictional forces set up by this relative motion have a tsry of the Navy 
reaction at the blade shank 14 in the vicinity of append- FiId Apr. 13,1953, Ser. No. 348,600 1 Claim. (a. 253-77) 
(Grauted under "Me 35, US. Code (1952), see. 266) age 24 and this tends to dampen any destructive vibra- 
tion by reducing vibration amplitude. 
This invention relates to turbo-machine blade vibration 10 In the embodiment of FIG. 2, the pins 38 and 40 have 
damping devices. the centrifugal force generated upon rotor actuation, ap- 
Vibration in the blades of the rotor of a turbo-machine,' plied transversely of their respective longitudinal axes. 
or a gas turbine, is a factor which has been the object The pins are urged against the sloped outer recess walls 
of considerable remedial attempts. Its harmful effects whereby the resulting cam action directs the pins against 
in turbo-machines are well known, and an object of this 15 the shank 42 with a continuous, calculatable force. The 
invention is to reduce blade vibration amplitude by induc- damping results from the combined effects of pins 38 and 
ing damping into the blading of a turbo-machine. 40 setting up frictional resistance between shank 42 and 
A more specific object of the invention is to induce the walls of the pin recesses, which frictional resistance to 
damping into the blade system of a turbo-machine to relative movement has a reaction applied to blade shank 
reduce the vibration amplitude by providing one or more eo 42 for rcducing blade vibration amplitude. 
pins that fit into openings in the machine rotor and con- Obviously many modifications and variations of the 
tact and bear against the blade shanks or appendages. present invention are possible in the light of the above 
fixed thereto, with a continuous centrifugal force where- teachings. It is therefore to be understood that within 
by in the event of incipient blade vibration, the bending the scope of the appended claim the invention may be 
of the blade produces relative motion between the blade 26 practiced otherwise than as specifically described. 
shank (or appendage) and the pin or pins and the rotor. The invention described herein may be manufactured 
Tbe combined effect produces frictional forces tending and used by or for the Government of the United States 
to dampen any destructive vibration. of America for governmental purposes without the pay- 
Other objects will become apparent in following the ment of any royalties thereon or therefor. 
description of the illustrated forms of the invention. 
In the drawing: In a machine rotor, a rotatable disc having a peripheral 
FIG. 1 is a fragmentary elevational view, with parts blade base socket and a recess separate from but ad- 
broken away, of a turbo-machine rotor and one blade jacent said socket, a single blade provided with a shank 
provided with the damping means; and with a base placed in said socket, a pin positioned in 
FIG. 2 is a fragmentary elevational view of another M said recess, said blade having its shank adjacent said 
turbo-machine rotor and blade provided with a modified recess, said recess being approximately radially disposed 
form of vibration damping means. with respect to the axis of the disc, an appendage pro- 
In FIG. 1 there is a turbo-machine rotor disc 10 pro- truding laterally from the blade shank, and said pin being 
vided with blade 12 that is one of a group normally found freely movable in said recess subject to Centrifugal forces 
in a typical turbine or compressor rotor. The blade has 'O when said disc is rotated with a portion thereof adapted 
a shank 14, at the inner end of which there is the blade to contact said appendage to transmit force from the pin 
anchor or base 16 fitted in the rotor disc peripheral socket to the shank of the blade whereby on disc rotation said 
18. The means to induce damping into the blade system pin is forced outwardly into engagment with said ap- 
consist of a pin 20 loosely fitted for free axial movement pendage to reduce the vibrational amplitude of said 
h a generally radial recess 22 in the rotor, the pin con- 46 blade shank. 
tacting a lateral appendage 24 extending from blade 
shank 14. Relieved portion defining recess 2a in the References Cited in the file of thii patent 
UNITED STATES PATENTS rotor disc surface accommodates the appendage 24. 
the blade anchor or base 34 is fitted, blade 36 extending 1,833,754 
through the rotor disc periphery in the usual manner. 1,856,786 
Vibration damping means in this instance consist of pins 2,349,187 
38 and 40, one on each side of blade shank 42, and each 2,618,460 
disposed in its recess in rotor disc 30. The pin recesses 66 2,651,494 
open tOward Or face the blade shank 42 and each has a 2,669,383 
* l o P h  outer wall that acts as a cam in the operation of 2,783,023 
the damping means. 
En operation of the embodiment of mG. 1, rotor disc 
10 is brought up to speed during which period centri- Bo 168,997 
fuga1 force acting on pin 20 and in a direction generally 670,665 
parallel to its longitudinal axis, urges the pin outwardly 
of the rotor and against appendage 24 fixed to shank 14. 
Regardless of how close machining tolerances are kept, S.A& Jownal, February, 1948. Pages 32-34, 
2,997,274 
'I'URBo-MACMNE BLADE VIBRA"+IoN D ~ E R  
Mom p* -On, cW'*ma, Ohio, the 
the 
ao What is claimed is: 
In FIG. 2 the rotor disc 30 has blade socket 32 in which 6o 
Paget ________________ Nov. 24, 1931 
Rice --_______-______-- May 3, 1932 
Meyer ________________  May 16, 1944 
Williams ______________  Nov. 18, 1952 
Persson --------------_ Sept. 8, 1953 
Purvis ________________ Feb. 16, 1954 
Stalker __-____________ Feb. 26, 1957 
Great Britain __________ Sept. 12, 1921 
Great Britain _________- Apr. 23, 1952 
OTHER REFERENCES 
FOREIGN PATENTS 


Turbo-machine blade vibration damper Patent

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