US008123487B2

(12) United States Patent (10) Patent N0.: US 8,123,487 B2

Bayer et al. (45) Date of Patent: Feb. 28, 2012

(54) ROTOR FOR A TURBO ENGINE (56) References Cited

(75) Inventors: Erwin Bayer, Dachau (DE); Bertram U.S. PATENT DOCUMENTS
Kopperger, Dachau (DE) 1,325,208 A * 12/1919 Rice ............................ .. 416/215
1,470,499 A * 10/1923 Steenstrup .. 29/889.21
(73) Assignee: MTU Aero Engines GmbH, Munich 2,264,877 A *
2,494,658 A *
12/1941 Hezekiah ..... ..
1/1950 Highberg et a1. ..
415/209.4
416/215
(DE) 2,988,324 A * 6/1961 Sutters .................... .. 416/201 R
3,532,438 A 10/1970 Freyman et al.
Notice: Subject to any disclaimer, the term of this 3,625,634 A * 12/1971 Stedfeld .................. .. 416/198R
patent is extended or adjusted under 35 4,339,229 A * 7/1982 Rossman . ... ... . . . . . .. 416/218

4,397,609 A * 8/1983 Kochendorfer 416/214R

U.S.C. 154(b) by 1207 days. 4,684,325 A * 8/1987 Arnold ......... .. 416/215
4,743,166 A * 5/1988 Elston et a1. 416/215
(21) Appl. N0.: 10/582,694 5,061,152 A * 10/1991 Marey .......... .. 415/150
5,263,823 A * 11/1993 Cabaret et al. 416/218
5,332,360 A * 7/1994 Correia et al. . 415/209.3
PCT Filed: Nov. 20, 2004 5,421,703 A * 6/1995 Payling ............ .. 415/209.4
(22) 5,474,419 A * 12/1995 ReluZco et a1. 415/209.4
5,797,725 A * 8/1998 Rhodes .................... .. 415/209.2
5,941,688 A 8/1999 Dambrine
(86) PCT No.: PCT/DE2004/002571 6,086,327 A * 7/2000 Mack et al. ................. .. 415/160
6,790,000 B2* 9/2004 Wolf ........................... .. 415/165
§ 371 (00)’
(2), (4) Date: Jul. 6, 2007 FOREIGN PATENT DOCUMENTS
CH 497 641 10/1970
(87) PCT Pub. No.: WO2005/056983 DE 2 027 861 12/1971
DE 10163 951 C1 12/2002
PCT Pub. Date: Jun. 23, 2005 GB 1266976 3/1972
* cited by examiner
(65) Prior Publication Data
Primary Examiner * Nathaniel Wiehe
US 2008/0025844 A1 Jan. 31, 2008
Assistant Examiner * Aaron R Eastman

(30) Foreign Application Priority Data (74) Attorney, Agent, or Firm * CroWell & Moring LLP
(57) ABSTRACT
Dec. 13, 2003 (DE) ................................ .. 103 58 421
A rotor for a turbo engine is disclosed including a rotor base
(51) Int. Cl. body and a plurality of rotor blades distributed over the cir
B64C 11/04 (2006.01) cumference of the rotor base body. The rotor base body is
formed by at least one ring-shaped element made of a metal
(52) US. Cl. ................................................. .. 416/219 R
matrix composite material. The rotor blades are attached by
(58) Field of Classi?cation Search ................ .. 416/215,
footing to the rotor base body in such a Way that the footing is
416/214 A, 214 R, 220 R, 221, 248, 219 R,
positioned in a ?ber-free area of the rotor base body.
416/220 A, 219 A, 204 A; 29/88921
See application ?le for complete search history. 2 Claims, 3 Drawing Sheets
US. Patent Feb. 28, 2012 Sheet 1 of3 US 8,123,487 B2
US. Patent Feb. 28, 2012 Sheet 2 of3 US 8,123,487 B2

Fig.3
US. Patent Feb. 28, 2012 Sheet 3 of3 US 8,123,487 B2

30/32

is

/ 31/32 33/35
26
3B

28

3L- Fig.1.
 US 8,123,487 B2
1 2
ROTOR FOR A TURBO ENGINE of the rotor blades engage in a corresponding recess, i.e.,
indentation in the area of the ring-shaped elements, namely
This application claims the priority of International Appli betWeen ?ber-reinforced areas of the tWo ring-shaped ele
cation No. PCT/DE2004/002571, ?led Nov. 20, 2004, and ments. Each rotor blade is preferably positioned With one
German Patent Document No. 103 58 421.8, ?led Dec. 13, platform each betWeen peripheral protrusions of the tWo ring
2003, the disclosures of Which are expressly incorporated by shaped elements that are on the outside radially, With the ends
reference herein. of the platforms being in contact With the peripheral protru
sions.
BACKGROUND AND SUMMARY OF THE According to an alternative advantageous embodiment of
INVENTION
the present invention, the rotor base body is formed by a
ring-shaped element made of a metal matrix composite mate
The invention relates to a rotor for a turbo engine, in par
ticular a gas turbine.
rial (MMC material), sections of the ring-shaped element on
According to the state of the art, a distinction is made in the outside axially being ?ber-reinforced and a section in
principle betWeen tWo types of rotors for a turbo engine, betWeen being designed to be ?ber-free, With the blade foot
namely so-called integrally bladed rotors and rotors in Which ing of the rotor blades being secured in the ?ber-free section.
the blades are inserted, i.e., anchored, in a rotor base body by Boreholes running radially are preferably created in the ?ber
a footing. free section of the ring-shaped element, each rotor blade
Integrally bladed rotors are referred to either as BLISK being anchored by footing in a borehole.
(bladed disk) or BLING (bladed ring), depending on Whether 20
the rotor base body is disk-shaped or ring-shaped. In such BRIEF DESCRIPTION OF THE DRAWINGS
integrally bladed rotors, the rotor blades are ?xedly con
nected to the ring-shaped or disk-shaped rotor base body and Exemplary embodiments of the present invention are
thus form an integral part of the rotor base body. Production of explained in greater detail on the basis of the draWings, With
such integrally bladed rotors is complex and may be per 25 out being limited thereto. They shoW:
formed, for example, by milling from a solid on a 5-axis FIG. 1 illustrates a detail of an inventive rotor according to
milling machine. One disadvantage of integrally bladed a ?rst exemplary embodiment of the invention shoWn in a
rotors in a BLING or BLISK design is the poor possibility of schematic perspective side vieW;
repairing them. FIG. 2 illustrates an enlarged detail of the rotor according
Rotors in Which the rotor blades are inserted into the rotor 30 to FIG. 1;
base body via footing are easier to manufacture and repair FIG. 3 illustrates the rotor according to FIG. 1 in an
than integrally bladed rotors but they are much heavier than exploded diagram; and
integrally bladed rotors because the connection of the rotor FIG. 4 illustrates a detail of an inventive rotor according to
blades to the rotor base body by Way of the blade footing is a second exemplary embodiment of the present invention in a
under high stresses due to centrifugal forces and therefore 35 schematic perspective side vieW.
must be designed With a reliable construction. In the related
art, the rotor base body is designed in the shape of a disk in DETAILED DESCRIPTION OF THE DRAWINGS
rotor designs in Which the rotor blades are anchored in the
rotor base body via the footing. The disk-shaped design of the The present invention is described in greater detail beloW
rotor base body and the connection of the rotor blades to the 40 With reference to FIGS. 1 through 4.
rotor base body via suitably dimensioned blade feet results in FIGS. 1 through 3 shoW an inventive rotor 10 for a turbo
a heavy Weight of the rotor, Which is a disadvantage of this engine, in particular for a gas turbine, in different vieWs. FIG.
design principle. 1 shoWs a detail of the rotor 10 in a perspective side vieW, With
Against this background, the object of the present inven FIG. 1 shoWing an approximately 900 detail, i.e., a quarter
tion is to propose a novel rotor for a turbo engine, in particular 45 circle detail of the essentially closed rotor 10. FIG. 2 shoWs an
for a gas turbine. enlarged detail of the rotor 10 in the area of tWo rotor blades;
According to this invention, the rotor base body is formed FIG. 3 shoWs an exploded diagram of the rotor 10. The rotor
by at least one ring-shaped element made of a metal matrix 10 is preferably used in a turbine or a compressor of an
composite material (MMC material), Where the rotor blades aircraft engine.
are attached to the rotor base body by footing so that the 50 The rotor 10 according to FIGS. 1 through 3 has a rotor
footing is positioned in a ?ber-free area of the rotorbase body. base body 11 plus multiple rotorblades 12 distributed over the
In the sense of the present invention, a rotor for a turbo circumference of the rotor base body 11. It is Within the scope
engine is proposed, preferably having a loW Weight on the one of the present invention for the rotor base body 11 to be
hand While being easy to manufacture and repair on the other formed by at least one ring-shaped element made of a metal
hand. Thus, in the sense of the present invention, the rotor 55 matrix composite material and for the rotor blades 12 to be
base body is formed from at least one ring-shaped element attached to the rotor base body by footing in such a Way that
made of a metal matrix composite material. The design of the the footing is positioned in a ?ber-free area of the rotor base
rotor base body has at least one ring-shaped element and, body 11.
manufacturing it by the MMC technology, alloWs a de?nite In the exemplary embodiment according to FIGS. 1
Weight reduction in comparison With the rotors knoWn from 60 through 3, the rotor base body 11 is made of tWo ring-shaped
the related art. In addition, individual rotor blades can be elements 13 and 14, the tWo ring-shaped elements 13 and 14
replaced easily When repairing the rotor. each being made of a metal matrix composite material. This
According to an advantageous re?nement of the present can be seen in FIGS. 2 and 3 in particular, Where the high
invention, the rotor base body is comprised of tWo ring tensile ?bers 15 are integrated into the metal matrix material
shaped elements made of a metal matrix composite material 65 of the ring-shaped elements 13 and 14 are shoWn in schematic
(MMC material), the rotor blades being attached betWeen the diagrams. In the exemplary embodiment illustrated in FIGS.
tWo ring-shaped elements on the outer end radially. Blade feet 1 through 3, each of the tWo ring-shaped elements 13 and 14
 US 8,123,487 B2
3 4
has a corresponding area 16 and/ or 17 in Which the high 33. The rotor blades 28 are mounted With footing 34 on the
tensile ?bers 15 are located, this area thus being designed as ring-shaped element 29 of the rotor base body 27 in this
a ?ber-reinforced area. ?ber-free section 33.
The rotor blades 12 are mounted on the outer end radially As FIG. 4 indicates, boreholes 35 running radially are
of the rotor base body 12 betWeen the tWo ring-shaped ele created in the ?ber-free section 33 of the ring-shaped element
ments 13 and 14, each rotor blade 12 being positioned With a 29. The rotor blades 28 can be inserted into the boreholes 35
footing 18 betWeen the ?ber-reinforced areas 16 and 17 of the from a position on the inside radially, Whereby according to
tWo ring-shaped elements 13 and 14. As shoWn in FIG. 3 in FIG. 4 a rotor blade 28 is insertable into a borehole 35 begin
particular, the tWo ring-shaped elements 13 and 14 each have ning With the blade pan 36. The rotor blade 28 is then forced
radially outWard until the footing 34 of the rotor blade 28
a recess, i.e., indentation 19 in Which the footing 18 engages
comes to rest against a stop 37 integrated into the borehole 35.
in the assembled state of the rotary 10. The inside contour of
The stop 37 thus limits the outWardly directed radial displace
the recesses 19 is thus adapted to the outside contour of the
ability of the rotor blades 28 in the boreholes 35.
blade feet 18.
Rotor blades 36 inserted into the boreholes 35 are held in
As can be seen in FIG. 2 in particular, a platform 20 of the
rotor blades 12 is connected to the footing 18 of the rotor
this position by a retaining ring (not shoWn). The retaining
ring that is not shoWn is in contact With the radially inside end
blades 12; in the installed state of the rotor 10, the ends of the
of the boreholes 35 over the entire circumference of the
platforms 20 that are on the outside axially are in contact With
peripheral protrusions 38 that are on the outside radially of the
ring-shaped element 29, pressing radially outWard so that the
rotor blades 28 are rigidly connected to the ring-shaped ele
tWo ring-shaped elements 13 and 14. The platforms 20 of the
20 ment 29 in an airtight connection. To increase the strength of
rotor blades 20 are thus ?ush With the protrusions 38 on the
the ring-shaped element 29, the high-tensile ?bers 32 may be
radially outer end of the ring-shaped elements 13 and 14.
Wrapped around the boreholes 35 in a sinusoidal or cosinu
Starting from the platforms 20, the blade pans 21 of the rotor soidal form in the area of the boreholes 35.
blades 12 extend radially outWard.
These tWo exemplary embodiments having in common the
The tWo ring-shaped elements 13 and 14 of the rotor base
fact that at least one ring-shaped element made of a metal
body 11 are joined together on the sections 22 and/or 23 that
matrix composite material is used as the rotor base body. The
are on the inside radially. The sections 22 and 23 on the inside
ring-shaped element or each ring-shaped element of the rotor
radially, Where the ring- shaped elements 13 and 14 are joined base body has at least one ?ber-reinforced section and/or area
together, are designed to be ?ber-free. Several boreholes 24
and at least one ?ber-free area, With the footing of the rotor
distributed over the circumference are introduced into these
30 blades running in the ?ber-free area of the ring-shaped ele
sections 22 and 23 that are on the inside radially. For detach
ment or each ring-shaped element. A de?nite Weight reduc
able connection of the tWo ring-shaped elements 13 and 14,
tion for rotors of a turbo engine can be achieved With such a
bolt-like screW connectors 25 engage in these boreholes 24.
design. Furthermore, such rotors are easy to manufacture and
Thus, the tWo ring-shaped elements 13 and 14 of the rotor
base body 11 are securely held together by the screW connec
repair.
35 The invention claimed is:
tors 25 and the rotor blades 12 are securely anchored by their
1. A rotor for a turbo engine, comprising:
footing 18 in the corresponding recesses 19 in the ring-shaped
a rotor base body, Wherein the rotor base body includes a
elements 13 and 14. The exemplary embodiment illustrated in
?ber-reinforced area and a ?ber-free area; and
FIGS. 1 through 3 has a particularly simple design of the
a rotor blade With a footing;
inventive rotor.
40 Wherein the footing is positioned in the rotor base body in
FIG. 4 shoWs a second exemplary embodiment of an inven
the ?ber-free area;
tive rotor 26. The rotor 26 of the embodiment of FIG. 4 also
Wherein the rotor base body includes a ring-shaped ele
has a rotor base body 27 and a plurality of rotor blades 28
ment and Wherein the ring-shaped element includes the
distributed over the circumference of the rotor base body 27.
?ber-reinforced area and the ?ber-free area;
In the exemplary embodiment in FIG. 4, the rotor base body
Wherein the ring-shaped element includes a second ?ber
27 is formed by a ring-shaped element 29, With the ring
reinforced area and Wherein the ?ber-free area is dis
shaped element 29 being made of a metal matrix composite
posed betWeen the ?ber-reinforced area and the second
material.
?ber-reinforced area;
The ring-shaped element 29 of the exemplary embodiment and Wherein the ?ber-free area de?nes a borehole and
of FIG. 4 thus has a ?ber-reinforced area 30 and/ or 31 on the
Wherein the footing is positioned in the borehole.
axially outer sections; FIG. 4 shoWs schematically the high 2. The rotor according to claim 1, Wherein the borehole
tensile ?bers 32 running inside the ?ber-reinforced areas 30
includes a stop and Wherein the footing engages the stop.
and 31. In an inner section axially, i.e., betWeen the tWo areas
30 and 31, the ring-shaped element 29 has a ?ber-free section * * * * *