JP3493764B2 - After-burner flap mounting structure for jet engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flap mounting structure for an afterburner for a jet engine. 2. Description of the Related Art FIGS. 5 to 7 show an example of an afterburner-equipped jet engine (turbofan engine) as an aircraft engine.
A compressor 2 for compressing the taken-in air, a combustor 3 for mixing and burning the compressed air with fuel, a turbine 4 for driving the fan 1 and the compressor 2 by the combustion gas of the combustor 3, and a new compressor. And an afterburner section 5 for burning the fuel added to the fuel cell. [0003] The afterburner section 5 is provided with a flame stabilizer 7 for forming a turbulent flow area 6 on the downstream side, a fuel nozzle 8 for ejecting fuel, and an ignition torch 9. By injecting the combustion gas from the liner 11 provided inside the engine outer cylinder 10,
The thrust is increased. The fan flow 12 branched from the fan 1
The core stream 13 discharged from the compressor 2, the combustor 3, and the turbine 4 is passed through a mixer 14 to promote mixing. The afterburner 5 at the rear end of the engine outer cylinder 10 is provided with an exhaust nozzle 15 whose opening can be adjusted as shown in FIG.
As shown in FIG. 7, a master flap 16 and a seal flap 17
And are alternately arranged so that the seal flaps 17 are located inside, and these are attached to a heat-resistant alloy hinge portion 18 attached to the rear end of the engine outer cylinder 10. A pivot 19 is provided so as to be openable and closable about a pin 19 extending in the tangential direction, and an uneven cam surface 20 is formed on the outer surface of the master flap 16. The drive ring 22 is attached to a drive ring 22 disposed on the outer peripheral side, and the drive ring 22 can be operated by a drive device 23 such as a cylinder that can expand and contract in the axial direction of the engine outer cylinder 10. Incidentally, reference numeral 24 denotes a liner 11 and each flap 16,
17 is a heat shielding seal provided therebetween. [0007] The seal flap 17 has a hinge 18
Is fixed to the mounting plate 25 by welding. When a larger thrust is required, such as when the aircraft rises rapidly, the afterburner unit 5
The fuel is sprayed into the mixed gas flow from the fuel nozzle 8 and the fuel is burned. Then, the fuel is explosively burned, and a flame is formed on the rear side of the flame stabilizer 7, and the temperature of the mixed gas flow ejected to the outside of the engine rises. When the temperature of the mixed gas flow increases, the volume of the mixed gas flow increases, so that the flow velocity of the mixed gas flow ejected to the outside of the engine increases, and the thrust of the engine increases. At this time, a driving device 23 such as a cylinder is extended and contracted to drive the driving ring 22, the copying roller 21, the cam surface 20.
Through the master flap 16 and the seal flap 17
By opening and closing, the cross-sectional area of the flow path of the exhaust nozzle portion 15 is changed, so that the thrust can be adjusted. [0012] However, the above-mentioned conventional flap mounting structure of the afterburner for a jet engine has the following problems. That is, in order to reduce the weight and improve the heat resistance of the afterburner portion 5, the use of a flap plate such as a seal flap 17 made of fiber reinforced ceramics has been studied. 1
7 cannot be fixed directly to the hinge 18 made of a heat-resistant alloy by welding, so that there is difficulty in mounting. Here, it is generally considered that a rivet is used to attach the seal flap 17 made of fiber reinforced ceramics. However, when a rivet is used, the head of the rivet projects to the combustion gas side. There is a problem that the temperature rises locally and the material becomes unbearable,
There is a problem that a gap is formed between the metal hinge portion 18 or the rivet and the seal flap 17 made of fiber reinforced ceramics having a small coefficient of thermal expansion due to a difference in thermal expansion. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a flap mounting structure for an afterburner for a jet engine, which allows a flap plate made of fiber reinforced ceramics to be mounted without any trouble. According to the present invention, there is provided a flap mounting structure for an afterburner for a jet engine, wherein a plurality of flap plates are mounted on the outlet side of an afterburner mounted on the jet engine via a hinge so as to be openable and closable. At
The metal hinge mounting plate and the fiber reinforced ceramic flap plate are fastened using a countersunk screw with a tapered head and a self-locking nut, and into the screw through hole on the flap plate side. Forming a tapered countersunk portion large enough to hide the head of the flathead screw, and interposing an elastic body for adjusting a fastening force between the mounting plate and a self-locking nut screwed onto the flathead screw. The present invention relates to a flap mounting structure for an afterburner for a jet engine. The operation of the present invention is as follows. A countersunk portion larger than the head of the flat head screw is formed in the screw through hole of the flap plate made of fiber reinforced ceramics. By preventing the head of the flat head screw from protruding from the inner surface of the seal flap when the head thermally expands in the radial direction,
The head of the countersunk screw is prevented from projecting into the combustion gas to locally increase the temperature, so that the countersunk screw can be made of a general heat-resistant metal material without using a material having excellent heat resistance. It becomes possible. Further, since the head of the flat head screw is prevented from locally becoming high in temperature as described above, the amount of expansion of the flat head screw in the axial direction is reduced, and the difference in expansion between the flat head screw and the seal flap is reduced. Thus, the gap due to the difference in thermal expansion between the mounting plate of the hinge portion and the seal flap made of fiber reinforced ceramics is reduced. Further, since a fastening force adjusting elastic body such as a disc spring is interposed between the mounting plate and the self-locking nut screwed onto the countersunk screw, even if the countersunk screw extends in the axial direction, The disc spring is elastically deformed, and the gap between the mounting plate at the hinge portion and the seal flap made of fiber-reinforced ceramics is absorbed, so that the seal flap is securely held by the mounting plate. Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of the present invention. The structure of the jet engine itself is shown in FIG.
7 is almost the same as that of FIG.
7 to FIG. In the figure, reference numeral 18 denotes a hinge portion made of a metal (made of a heat-resistant alloy) attached to the rear end of the engine casing 10;
Reference numeral 9 denotes a pin of the hinge part 18, and reference numeral 25 denotes a mounting plate of the hinge part 18. When a flap plate such as a seal flap 26 made of fiber reinforced ceramics is used for the exhaust nozzle portion 15 of the afterburner 5, a mounting plate 25 of the hinge portion 18 and a seal flap 2 made of fiber reinforced ceramics are used.
6, screw through holes 27 and 28 are formed, and the screw portion 31 of the flat head screw 30 having the tapered head 29 is inserted through the screw through holes 27 and 28 from the screw through hole 27 side. Then, a self-lock nut 32 is fastened to the screw portion 31. The screw portion 31 and the body of the flathead screw 30 are
The diameter is made smaller than the screw through holes 27 and 28 in consideration of the radial thermal expansion. In the seal flap 26, a portion of the screw through hole 27 corresponding to the head 29 of the flat head screw 30 is provided.
A tapered counterpart 33 having a size that allows the head 29 to be hidden is formed. Preferably, when the flat head screw 30 is thermally expanded in the longitudinal direction and the radial direction, the head 29 of the flat head screw 30 is smaller than the same level as the inner surface of the seal flap 26 and does not protrude from the inner surface of the seal flap 26. I do. Further, the self-locking nut 32 is provided as shown in FIG.
As shown in FIG. 3, the screw hole 34 is provided with a non-circular (slightly elliptical or triangular shape rather than a circular shape) screw. To generate a clamping force by the deformation force,
This is to prevent loosening. Further, between the mounting plate 25 and the self-locking nut 32 screwed to the flathead screw 30, an elastic body for adjusting the fastening force such as a flathead spring 35 and flat washers 36, 36 are interposed. Next, the operation will be described. The operation of the jet engine and afterburner is the same as in FIGS. In the present invention, a flap plate such as a seal flap 26 made of fiber reinforced ceramic is attached to a mounting plate 25 of a hinge portion 18 made of a metal (made of a heat-resistant alloy) with a flathead screw 30.
And a self-locking nut 32 which is provided with a non-circular screw hole 34 so as not to be loosened. Therefore, the flat head screw 30 is heated by the high-temperature combustion gas ejected from the afterburner 5, and thermally expands in the axial direction and the radial direction. At this time, the head 29 of the flat head screw 30 is inserted into the screw through hole 27 of the seal flap 26 made of fiber reinforced ceramics.
The countersunk portion 33 is formed to be larger than
When the head 29 of the flat head screw 30 is thermally expanded in the radial direction, the head 29 of the flat head screw 30
The head 9 of the flat head screw 30 is prevented from projecting into the combustion gas to locally increase the temperature by preventing the head 9 from being lower than the inner surface of the seal flap 26 at the same level or lower than the inner surface of the seal flap 26. . Accordingly, it is possible to provide a general heat-resistant metal material sufficiently without using the flathead screw 30 as a material having excellent heat resistance. Further, since the head 29 of the flat head screw 30 can be prevented from being locally heated to a high temperature, the amount of extension of the flat head screw 30 in the axial direction is reduced. The difference in elongation can be kept small. Thereby, the mounting plate 25 of the hinge part 18 and
A gap due to a difference in thermal expansion between the seal flap 26 and the fiber reinforced ceramic seal flap 26 is reduced. Further, since a fastening force adjusting elastic body such as a disk spring 35 is interposed between the mounting plate 25 and the self-locking nut 32 screwed to the disk screw 30, the disk screw 30 is axially displaced. Even if it expands, the disc spring 35 elastically deforms,
The gap between the attachment plate 25 of the hinge portion 18 and the seal flap 26 made of fiber reinforced ceramics is absorbed, and the attachment plate 25 can reliably hold the seal flap 26. The reason why the coned disc spring 35 is used as the elastic body for adjusting the fastening force is that it can be easily interposed at a narrow interval as compared with the coil spring, and the thermal expansion of the coned screw 30 can be improved. Although the change in the fastening force before and after can be relatively easily grasped, the fastening force adjusting elastic body may be a coil spring or another elastic body. The present invention is not limited to the above-described embodiment, but can be applied to a master flap. In addition, various changes can be made without departing from the gist of the present invention. Of course. As described above, according to the after-burner flap mounting structure for a jet engine of the present invention,
The following excellent effects can be obtained. A countersunk portion larger than the head of the flat head screw is formed in the screw through hole of the flap plate made of fiber reinforced ceramics. When the head thermally expands in the radial direction, the head of the flat head screw does not protrude from the inner surface of the seal flap, so that the head of the flat head screw protrudes into the combustion gas and is locally heated. Therefore, even if the flathead screw is not made of a material having excellent heat resistance, a general heat-resistant metal material can be sufficiently provided. In addition, since the temperature of the head of the flat head screw can be prevented from locally increasing, the amount of expansion of the flat head screw in the axial direction is reduced, and the difference in expansion between the flat head screw and the seal flap is reduced. Therefore, a gap due to a difference in thermal expansion between the mounting plate of the hinge portion and the seal flap made of fiber reinforced ceramics can be reduced. Further, since an elastic body for adjusting the fastening force such as a disk spring is interposed between the mounting plate and the self-lock nut screwed onto the disk screw, even if the disk screw extends in the axial direction,
The disc spring is elastically deformed to absorb a gap between the mounting plate at the hinge portion and the seal flap made of fiber reinforced ceramics, so that the mounting plate can reliably hold the seal flap.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of one embodiment of the present invention. FIG. 2 is a plan view of FIG. FIG. 3 is a partially enlarged sectional view of FIG. 1; FIG. 4 is an enlarged plan view of the self-locking nut of FIG. 1; FIG. 5 is a schematic side sectional view of a general turbofan engine with an afterburner. 6 is a partially enlarged view of a conventional afterburner section, and is a view in which FIG. 7 is cut away from a VI-VI direction. FIG. 7 is a view taken along the line VII-VII in FIG. 6; [Description of Signs] 5 Afterburner 16 Master flap (flap plate) 18 Hinge 25 Mounting plate 26 Seal flap (flap plate) 27 Screw hole 29 Head 30 Countersunk screw 32 Self-locking nut 33 Countersunk unit 35 Disc spring ( Elastic body for adjusting the fastening force)

Claims (1)

(1) A flap mounting structure for an afterburner for a jet engine, wherein a large number of flap plates are openably and closably mounted via hinges on an outlet side of an afterburner mounted on the jet engine. The metal hinge mounting plate and the fiber reinforced ceramic flap plate are fastened using a countersunk screw with a tapered head and a self-locking nut, and into the screw through hole on the flap plate side. Forming a tapered countersunk portion large enough to hide the head of the flathead screw, and interposing an elastic body for adjusting a fastening force between the mounting plate and a self-locking nut screwed onto the flathead screw. A flap mounting structure for an afterburner for a jet engine, characterized in that: