U.S. patent number 3,663,119 [Application Number 05/026,215] was granted by the patent office on 1972-05-16 for bladed rotors.
This patent grant is currently assigned to Dowty Rotol Limited. Invention is credited to Ivor Harold Brooking, John Alfred Chilman.
United States Patent |
3,663,119 |
Brooking , et al. |
May 16, 1972 |
BLADED ROTORS
Abstract
A bladed rotor having blading of flow-varying type, including,
carried within its hub, a pump operable upon rotor rotation and
valve means for controlling the flow of pressure fluid from the
pump to a fluid-pressure-operable actuator for adjusting the
blading. Conduit means, provided for conducting fluid to the pump
inlet, are connectable to a source external of the rotor.
Inventors: |
Brooking; Ivor Harold (Wotton,
EN), Chilman; John Alfred (Painswick, EN) |
Assignee: |
Dowty Rotol Limited
(Gloucester, EN)
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Family
ID: |
10183389 |
Appl.
No.: |
05/026,215 |
Filed: |
April 7, 1970 |
Foreign Application Priority Data
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May 3, 1969 [GB] |
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22,681/69 |
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Current U.S.
Class: |
416/157R;
416/158; 416/157A; 416/160 |
Current CPC
Class: |
F01D
7/00 (20130101); F05D 2260/76 (20130101); F05D
2260/74 (20130101) |
Current International
Class: |
F01D
7/00 (20060101); B64c 011/38 () |
Field of
Search: |
;416/155,156,157,158,159,160 ;184/6F,6S,6Y,6Z ;418/88 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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728,851 |
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Nov 1942 |
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DD |
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946,590 |
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Aug 1956 |
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DT |
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Primary Examiner: Schwadron; Martin P.
Assistant Examiner: Schimikowski; Clemens
Claims
We claim:
1. In combination, a bladed rotor whose blading is of flow-varying
type, an engine adapted to drive said rotor, a lubrication system
forming part of said engine and including a sump and a low pressure
pump, drivable by the engine, which is connected to draw liquid
from the sump and to deliver that liquid at low pressure, said
bladed rotor comprising a hub and, carried within the hub, a high
pressure pump with means fast with non-rotatable engine structure
whereby the pump is driven upon rotation of the rotor, a
fluid-pressure-operable actuator for adjusting the blading, and
valve means for controlling the flow of pressure fluid from said
pump to the actuator, conduit means for conducting fluid from said
low pressure pump to the inlet of the high pressure pump, said
conduit means comprising one part provided in non-rotatable engine
structure and another part carried by the rotor and rotatable
therewith, low pressure fluid transfer means associated with both
said engine and said rotor and with which said one part and said
other part of the conduit means are connected thereby to afford
substantially sealed fluid connection of those parts whereby low
pressure liquid from said low pressure pump can pass to the inlet
of said high pressure pump, and further conduit means connected
between said valve means and said sump by way of said low pressure
fluid transfer means whereby liquid exhausting from the actuator
can pass to said sump.
2. A bladed rotor as claimed in claim 1, wherein further conduit
means are provided whereby fluid exhausting from said actuator can
be directed through said fluid transfer means to said lubrication
system.
3. A bladed rotor as claimed in claim 1, wherein said pump is of
the internally-meshing lobed type, and the axis of its drive shaft
is coincident with the axis of rotation of the rotor.
4. A bladed rotor as claimed in claim 1, wherein said actuator is
of the vane-type.
5. A bladed rotor as claimed in claim 4, wherein drive means from
the actuator for adjusting the blading includes a balanced bevel
gear train.
6. A bladed rotor as claimed in claim 4, wherein the valve means is
arranged coaxially with respect to the actuator and within a hub
portion thereof.
7. A bladed rotor as claimed in claim 1, wherein said flow-varying
blading is of variable-pitch.
8. A bladed rotor as claimed in claim 2, wherein said fluid
transfer means comprises a sleeve fast with non-rotatable structure
and supporting for rotation, with the drive shaft of said rotor,
tubular members in part defining said conduit means and said
further conduit means.
9. A bladed rotor as claimed in claim 8, wherein the parts of the
conduit means and of the further conduit means defined by said
tubular members are placed in communication with ducts, in said
structure, which form the other parts of said conduit means,
through respective annular recesses and porting formed in said
sleeve.
10. In combination, a bladed rotor whose blading is of flow-varying
type, an engine having a drive shaft upon which said rotor is
mounted, a lubrication system forming part of said engine and
including a sump and a low pressure pump, drivable by the engine,
which is connected to draw liquid from the sump and to deliver that
liquid at low pressure, said bladed rotor comprising a hub and,
carried within the hub, a high pressure pump with means fast with
non-rotatable engine structure whereby the pump is driven upon
rotation of the rotor, a fluid-pressure-operable actuator for
adjusting the blading, and valve means for controlling the flow of
pressure fluid from said pump to the actuator, conduit means for
conducting fluid from said low pressure pump to the inlet of the
high pressure pump, said conduit means comprising one part provided
in non-rotatable engine structure and another part in the form of a
first tubular member carried by the rotor being rotatable therewith
and extending into said drive shaft coaxially thereof, low pressure
fluid transfer means associated with both said drive shaft and said
rotor with which said one part and said first tubular member are
connected thereby to afford substantially sealed fluid connection
of those parts whereby low pressure liquid from said low pressure
pump can pass to the inlet of said high pressure pump, and further
conduit means, including a second tubular member coaxial with said
first tubular member and also extending from said rotor into said
drive shaft coaxially thereof, which are connected between said
valve means and said sump by way of said low pressure fluid
transfer means whereby liquid exhausting from the actuator can pass
to said sump.
Description
This invention relates to bladed rotors.
According to this invention a bladed rotor whose blading is of
flow-varying type includes, carried within its hub, a pump operable
upon rotor rotation, valve means for controlling the flow of
pressure fluid from said pump to a fluid-pressure-operable actuator
for adjusting the blading, and conduit means for conducting fluid
to the inlet of the pump, said conduit means being connectible to a
source external of the rotor.
The conduit means is connectible to the source by way of fluid
transfer means whereby fluid can pass from non-rotatable structure
to the rotor.
In practice, the conduit means may be connected to the lubrication
system of an engine which is connected to drive the bladed
rotor.
Further conduit means may be provided whereby fluid exhausting from
said actuator can be directed through said fluid transfer means to
said lubrication system.
The pump may be of the internally-meshing lobed type and the axis
of its drive shaft may be coincident with the axis of rotation of
the rotor.
The actuator may be of the vane-type and drive means from the
actuator for adjusting the blading may include a balanced bevel
gear train. In this case the valve means may be arranged coaxially
with respect to the actuator and within a hub portion thereof.
The flow-varying blading is preferably of variable-pitch.
One embodiment of the invention will now be particularly described
by way of example with reference to the accompanying diagrammatic
drawings, of which,
FIG. 1 shows a gas turbine engine of the by-pass type having a
bladed rotor, which forms a by-pass fan, shown partly in
cross-section;
FIG. 2 is a cross-section of a gear casing forming part of the
construction shown in FIG. 1;
FIG. 3 is a perspective view with parts cut away, of the rotary
control valve, a vane actuator and the pitch-change pump for the
rotor.
With reference to FIG. 1 of the drawings, a bladed rotor 11
includes seventeen blades, two of which are shown at 12. The blades
are mounted in the hub 13 of the rotor so as to be variable in
pitch about their longitudinal pitch-change axes 14. The bladed
rotor 11 forms the by-pass fan of a gas turbine engine 15 of the
by-pass type. This engine includes a duct 16 within which the rotor
is rotatable. The inlet casing to the axial-flow compressor C of
the engine is shown at 17 and a gear casing 18 forming part of the
non-rotatable structure of the engine is provided ahead of the
engine compressor. The combustion chamber section of the engine is
shown at F and the turbine section at T. The compressor is
connected to drive the rotor 11 through reduction gearing housed in
the gear casing.
A pump 19 of the internally-meshing lobed type is mounted within
the hub 13 for rotation therewith, the axis of its drive shaft 20
being coincident with the axis 21 of rotation of the rotor. This
drive shaft is fixed to non-rotatable structure within the gear
casing 18, so that the pump 19 is operable when the rotor 11 is
being driven by the engine.
A conduit 22 is taken from a conventional lubrication system of the
engine 15. The lubrication system includes an engine-driven pump 81
which draws liquid from a sump S and which delivers liquid under
pressure to the anti-friction bearings of the rotating components
of the engine. The conduit 22 connects to a fluid transfer means,
shown diagrammatically in FIG. 1 at 23, designed to conduct
hydraulic liquid from non-rotatable structure of the gear casing 18
to a conduit 24 in the rotatable structure of the hub 13. The
conduit 24 connects with the inlet 25 of the pump 19. A conduit 26
is taken from the outlet 27 of the pump to a pitch control valve
assembly, shown generally at 28, which is rotatable with the hub 13
and which is mounted therein with its axis coincident with the axis
21.
A drain conduit 29 is taken from the valve assembly 28 to the fluid
transfer means 23 so that drain liquid can pass back from the hub
to a conduit 30 in the gear casing and back to the engine
lubrication system.
The pitch control valve assembly 28 is positioned within the hub 31
of a fluid-pressure-operable actuator 32 of balanced-vane type.
This actuator has its axis of rotation coincident with the axis 21
and includes a multiplicity of chambers 33 formed by a first
multi-vaned actuator part 34 and by a second multi-vaned actuator
part 35. Portions 36 and 37 of these parts carry respective bevel
gear rings 38 and 39 which mesh with bevel gears 40, one fast with
the root portion of each blade 12. As shown, the points of meshing
of the bevel gear rings 38 and 39 with each bevel gear 40 are
substantially diametrically opposed upon the latter.
An input member 41, mounted upon the non-rotatable structure of the
gear casing 18, is provided to operate the valve assembly 28
through an epicyclic gear train, diagrammatically shown by the box
42. This gear train drives a gear 43 fast with the displaceable
element 44 of the assembly 28, consequent movement of the element
controlling the operation of the actuator 32 and thus blade pitch.
Feedback means (not shown) is provided within the assembly by which
the actuator cancels out the input signal to the displaceable
element 44 as soon as the selected blade pitch adjustment has been
reached.
Such a pitch control valve assembly and associated pitch-change
actuator are disclosed in copending application Ser. No. 26,216,
filed Apr. 7, 1970.
With reference now to both FIGS. 1 and 2 of the drawings, the fluid
transfer means 23 shown diagrammatically in FIG. 1 is in FIG. 2
shown in detail within the gear casing 18. The drive shaft 20 for
the pump 19 passes completely through the means 23 and at its
right-hand end portion in the drawing carries a flange 45 which is
bolted at 46 to a shoulder 47 formed integrally with the casing 48
of the means 23 and projecting into a stepped bore 49 thereof. The
axis of the bore 49 is coincident with the axis 21, and the casing
48 is non-rotatable. A transfer sleeve 50 held against rotation by
means of a peg 51 is provided in the bore 49. Annular recesses 52
and 53 are provided on the exterior surface of this sleeve, with
three sealing rings 54, 55 and 56 provided in the positions shown.
Ports 57 and 58 respectively place the recesses 52 and 53 in
communication with annular recesses 59 and 60 on the inner surface
of the sleeve. The sleeve is of steel and has white metal bushes
61, 62 and 63 dove-tailed into its inner surface, as shown, for
rotational support of the rearward end portion of a tubular member
64 which is coaxial with, and which passes through, the main shaft
65 of the fan 12. The shaft 65 is partly supported by a ball
bearing 66 and is driven from the compressor C through reduction
gearing which includes a sun gear 67 mounted upon the output shaft
68 of the compressor, and planet gears 69 which are in mesh with
the sun gear and which are also in mesh with an internally-toothed
peripheral gear 70. The gear 70 is formed upon a cylindrical member
71, the forward end portion of which is splined at 72 to the
rearward end portion of the shaft 65. There are four planet gears
69 and they are suitably mounted for rotation in the fixed casing
48.
Within the tubular member 64 is a first tube 73 coaxial with that
member and screw-threadedly attached thereto. Within said first
tube there is a second tube 74 coaxial with the member 64 and
screw-threadedly attached thereto. Both the tubes 73 and 74 extend
forwardly with the member 63 to the valve assembly 28, the tubular
member and the two tubes being rotatable as one with the shaft 65.
In this way two conduit means are provided, the first between the
tube 73 and the tube 74, and the second between the tube 74 and the
shaft 20. The first conduit means is the conduit 24 of FIG. 1 while
the second is the conduit 29 of FIG. 1.
A second bearing, of roller type, shown at 80 in FIG. 2, supports
the rearward extremity of the shaft 65.
Carbon seals 75 and 76 are positioned between fixed and rotating
components of the transfer means as shown, spring-loaded means 77
and 78 being provided for axially loading the carbon rings in their
sealing condition.
The annuli 52 and 53 respectively align with the inlet duct 22 and
the return duct 30 shown in both FIGS. 1 and 2.
Although not shown in FIG. 1 there is a further conduit shown at
79, in FIG. 2, taken from the stepped bore 49 back to the sump S,
this to collect liquid which seeps past the seals and white metal
bushes in the transfer means.
In operation, when the engine 15 is operating to drive the by-pass
fan 11, hydraulic liquid from the engine lubrication system is
supplied at a base pressure of 40 p.s.i. through the conduit 22,
the fluid transfer means 23 and the conduit 24 to the inlet 25 of
the pump 19. The rotatable elements of the pump 19 receive this
liquid and it is pumped at higher pressure through the outlet 27
into the conduit 26. This high pressure liquid is thus available at
the pitch control valve assembly 28 for direction into the vane
actuator to effect blade pitch-change at the demands of the input
member 41.
Return liquid from the actuator 32, when pitch-change is actually
occurring, is allowed to pass back to the engine lubrication system
through the conduit 29, the transfer means 23 and the conduit
30.
During such operation the transfer means ensures that a minimum of
liquid leakage occurs from the base supply conduit 22 to either the
conduit 30 or the conduit 79, the sealing function being provided
partly by the sealing rings 54 and 55 and partly by the white metal
bushes 61 and 62. A slight seepage of liquid is permitted to occur
between the white metal bushes and the rotating member 64 for
lubrication purposes. This liquid passes, with any seepage past the
seals 54 and 56, into the drain conduit 79.
The construction described ensures that relatively hot lubricating
liquid delivered from the engine lubrication system is available at
the inlet 25 of the pump 19, as compared with the cooler liquid
which would have been available had the liquid been wholly
contained within the fan hub. This relatively hot liquid gives much
faster response at substantially all times during engine operation,
such response being very desirable for the by-pass fans of engines
of the by-pass type used in high speed aircraft where rapid
pitch-change is necessary in all phases of fan operation.
By arranging that the inlet of the pump receives liquid at a
substantial base pressure, there are likely to be no priming
difficulties and the pump will operate with good efficiency.
Further, the fact that no reservoir is provided in the hub of the
fan eliminates the need for reservoir-defining structure, and thus
the size and weight of the fan hub are appreciably reduced.
Although in the embodiment above described the bladed rotor is the
by-pass fan of a gas turbine engine of the by-pass type, in other
embodiments the invention is with advantage applied to bladed
rotors of the other kind, for example, propellers for aerial or
non-aerial use.
Also in other embodiments, instead of the blading being of
variable-pitch, it may be of variable-twist or variable-camber.
Again, the invention is not limited to blading of single tier form,
as in other embodiments the blading may be of multiple tier type,
one at least of the rows of which has flow-varying blading.
* * * * *