JP2001050448A - Joint structure of tubular member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deformation and breakage of even coupled tubular members of different coefficients of thermal expansion. SOLUTION: This joint structure is for two tubular members formed from materials of different coefficients of thermal expansion and coupled at opposed ends. An end 3a of one of the two tubular members is held between an end 2a of the other tubular member and a clamping member 5 secured to the end 2a of the other tubular member. The clamping member 5 is formed from the same material as the other tubular member or a material of a substantially identical coefficient of thermal expansion to that of the material thereof. The end 3a of the one tubular member is flared out in a direction perpendicular to the axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular member joint suitable for connecting cylindrical members having large dimensions and different thermal expansion coefficients from each other, such as a bypass duct of a jet engine. Regarding the structure.

[0002]

2. Description of the Related Art In recent years, composite materials (eg, CMC (carbon matrix ceramic)) which are lightweight and have excellent heat resistance.
Etc.) have been developed and are being used in various places. For example, as a member to which such a composite material is applied, it is considered to be applied to a portion of a gas turbine engine or the like which is in a high temperature state, particularly to a bypass duct of a jet engine which is required to be reduced in weight.

Conventionally, connection in a bypass duct of a jet engine has been performed by providing flanges as joints at ends of both members to be connected, and restraining the two flanges together with bolts or the like in a state where the two flanges are joined.

[0004]

However, when trying to connect a composite material and a metal material, two components having a difference in thermal expansion at the joint portion because the thermal expansion coefficient of the composite material is smaller than that of the metal material. And there is a possibility that deformation or breakage may occur. In particular, when a composite material is applied to a cylindrical member having a large size such as a bypass duct and being heated to a high temperature, it is not possible to employ a conventional means for fixing the both by bolts or the like.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a joint structure for a cylindrical member which can prevent deformation and breakage even when cylindrical members having different coefficients of thermal expansion are connected. Aim.

[0006]

The present invention has the following features to attain the object mentioned above. That is, the joint structure of the cylindrical member according to claim 1 is a joint structure of two cylindrical members formed of materials having different coefficients of thermal expansion and connected at the ends, and An end of one of the tubular members is sandwiched between an end of the other tubular member and a sandwiching member fixed to an end of the other tubular member, and the sandwiching member is formed of the other cylinder. It is formed of the same material as that of the tubular member or a material having substantially the same coefficient of thermal expansion, and a technique is employed in which the end of the one tubular member is bent along a direction intersecting the axis.

In this joint structure of a tubular member, the end of one tubular member is sandwiched between the end of the other tubular member and a holding member fixed to the end of the other tubular member. And
Since the holding member is formed of the same material or a material having substantially the same coefficient of thermal expansion as the other tubular member, and the end of one tubular member is bent along a direction intersecting the axis, the thermal expansion The direction intersecting the axis while the end of one of the cylindrical members is not fixed and the connection is maintained in a sandwiched state, that is, the contact surface Relative to each other, and the dimensional difference can be reduced.

[0008] In the joint structure of the tubular member according to the second aspect,
A technique is adopted in which the thickness of the end of the one cylindrical member is gradually increased toward the tip.

In this joint structure of a tubular member, the end of one tubular member is set to be gradually thicker toward the tip, so that the end of the other tubular member and the holding member are connected to each other. Even if the gap changes in size due to thermal expansion, the end of one of the tubular members is sandwiched by a portion having a thickness corresponding to the size after the change due to slip, thereby preventing rattling and leakage of internal gas. .

[0010] In the joint structure of the tubular member according to the third aspect,
A technology is adopted in which the other tubular member of the two tubular members is an engine body of a gas turbine engine, and one of the tubular members is a duct connected to the exhaust side of the engine body. You.

In the joint structure of the tubular members, the other tubular member of the two tubular members is an engine body of the gas turbine engine, and one tubular member is connected to the exhaust side of the engine body. Because it is a duct connected to
A composite material having high heat resistance but a relatively small coefficient of thermal expansion can be used for the duct on the exhaust side of the engine main body, which is in a high temperature state in the gas turbine engine.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a joint structure for a tubular member according to the present invention will be described with reference to FIGS. In these figures, reference numeral 1 denotes a jet engine, 2 denotes an engine body, 3 denotes a bypass duct, 4 denotes a nozzle, and 5 denotes a holding ring.

The joint structure of the tubular member of the present embodiment is shown in FIG.
As shown in FIG. 2, a main body side end 2a of an engine main body (the other cylindrical member) 2 of a jet engine (gas turbine engine) 1 and a cylindrical bypass duct ( One of the cylindrical members 3 is connected to the duct side end 3a. In addition,
The end on the exhaust side of the bypass duct 3 is connected to the nozzle unit 4. The engine body 2 is formed of a metal material of a heat-resistant alloy, and the bypass duct 3 has a higher heat resistance than a metal material, but has a smaller coefficient of thermal expansion than a metal material such as a composite material such as CMC. It is formed with.

The engine body 2 and the bypass duct 3
1 and 2, a duct side end 3a is sandwiched between a body side end 2a and a holding ring (holding member) 5 fixed to the body side end 2a. It is configured. Note that the holding ring 5 is formed of the same metal material as the engine body 2.

The duct-side end 2a is bent along a direction intersecting the axis C (in this embodiment, oblique to the axis C), and has a gradually increasing thickness toward the tip (reverse). (Tapered shape) is set. That is, the angle β of the duct side end 3a with respect to the axis C of the outer peripheral surface is set to be larger than the angle α with respect to the axis C of the inner peripheral surface.

The main body side end 2a has a main body holding portion 2b in contact with the inner peripheral surface of the duct side end 3a, and is disposed on the base end side of the main body holding portion 2b and protrudes outward in the radial direction. A main body side flange portion 2c is formed. The outer peripheral surface of the main body side holding portion 2b is set at an angle α with respect to the axis C similarly to the inner peripheral surface of the duct side end portion 3a.

The holding ring 5 has a ring-side flange portion 5a formed so as to protrude outward in the radial direction, and a ring-side holding portion 5b for holding the duct-side end portion 3a between the body-side holding portion 2b. Are formed. The holding ring 5 is fixed to the main body side end 2a by abutting the ring side flange 5a to the main body side flange 2c and fixing them together with bolts or the like. The inner peripheral surface of the ring-side holding portion 5b is set such that the angle with respect to the axis C is the angle β, similarly to the outer peripheral surface of the duct-side end 3a. That is, the duct-side end 3a is clamped while being fitted in a gap formed between the ring-side clamping portion 5b of the clamping ring 5 fixed to the ring-side flange 5a and the body-side clamping portion 2b. You.

In the present embodiment, when the engine body 2 and the bypass duct 3 are in a high temperature state and their dimensions are relatively changed due to a difference in the coefficient of thermal expansion, and the relative positions are changed, the dimensional differences are as follows. Is alleviated. That is, at the time of high temperature, the main body side end 2 having a relatively large coefficient of thermal expansion.
a and the holding ring 5 are larger in diameter than the duct side end 3a having a small coefficient of thermal expansion.

At this time, as shown in FIG. 3, the duct side end 3a is bent along a direction intersecting the axis C, so that the connection is maintained in the sandwiched state.
Slip occurs relatively along the direction intersecting the axis C (the direction of arrow A in the figure), that is, the contact surface (the outer peripheral surface of the main body side holding portion 2b and the inner peripheral surface of the ring side holding portion 5b), and the dimensional difference is caused. Can be alleviated.

Further, since the thickness of the duct side end 3a is gradually increased toward the tip, even if the gap between the main body side end 2a and the holding ring 5 changes in size due to thermal expansion, The duct-side end 3a is sandwiched by a portion having a thickness corresponding to the dimension after the change, thereby preventing rattling and leakage of internal gas.

Next, a second embodiment of the joint structure for a tubular member according to the present invention will be described with reference to FIG.

The difference between the second embodiment and the first embodiment is that the duct-side end 3a of the first embodiment is bent obliquely with respect to the axis C, whereas the second embodiment is different from the first embodiment. In the joint structure of the embodiment, as shown in FIG. 4, the duct side end 13a is bent along a direction orthogonal to the axis C, and is formed in a flange shape protruding radially outward. Is a point.

In the second embodiment, the main body side end 1
2a is constituted only by the main body side flange portion 12c, the cross-sectional shape of the holding side ring 15 at the ring side holding portion 15b is bent like a hook, and the duct side end portion 13a is formed by the end face of the main body side flange portion 12c and the end face thereof. In that it is sandwiched between the ring-side sandwiching portion 15b and the opposed surface of the ring-side sandwiching portion 15b. That is, in the present embodiment, even if a dimensional difference occurs due to a difference in thermal expansion coefficient, the duct-side end portion 13a slides in the radial direction with respect to the end surface of the main-body-side flange portion 12c and the opposing surface of the ring-side holding portion 15b. And the dimensional difference can be reduced.

Note that the present invention includes the following embodiments. In each of the above embodiments, the end shape of the bypass duct has an inverted taper shape in which the thickness gradually increases toward the tip. However, even when the thickness is constant, the dimensional difference due to the difference in the coefficient of thermal expansion can be reduced. it can. However, in this case, the gap between the ends of the bypass duct is widened due to thermal expansion as described above, which may cause rattling or leakage of internal gas. It is desirable to have a tapered shape. Further, the holding ring is formed of the same metal material as the engine body, but other materials may be used as long as they have substantially the same thermal expansion coefficient as the metal material of the engine body.

In the second embodiment, since the sliding direction of the duct side end 13a is the radial direction, no sliding occurs in the direction of the axis C. However, the sliding between the duct side end 13a and the main body side end 12a is not performed. A relatively large step is formed at the inner surface boundary, which may affect the flow of gas and the like inside. Therefore, in consideration of this point, the first embodiment in which the duct side end 3a is bent obliquely is preferable because the step is inclined and smooth at the inner surface boundary.

[0026]

According to the present invention, the following effects can be obtained.
According to the joint structure of the tubular member according to the first aspect, the end of one tubular member is formed by the end of the other tubular member and the holding member fixed to the end of the other tubular member. The holding member is formed of the same material or a material having substantially the same coefficient of thermal expansion as the other cylindrical member, and the end of one of the cylindrical members is bent along a direction intersecting the axis. Therefore, even if the respective dimensions relatively change in the radial direction due to the difference in the coefficient of thermal expansion, slippage occurs relatively in the direction intersecting the axis while the connection is maintained, so that the dimensional difference can be reduced. . Therefore, it is possible to prevent deformation, breakage, and the like caused by the difference in the coefficient of thermal expansion, and it is possible to improve the reliability of the joint portion. Further, the end shape of one of the tubular members can be configured relatively simply.

According to the joint structure of the cylindrical member according to the second aspect, the end of one of the cylindrical members is set to be gradually thicker toward the front end, so that the end of the other cylindrical member is formed. Even if the gap between the portion and the holding member changes in size due to thermal expansion, the end of one of the tubular members is held in a portion having a thickness corresponding to the changed size, and it is possible to prevent rattling, It is possible to prevent the occurrence of vibration, internal gas leakage, and the like at the joint portion.

According to the joint structure of the tubular member according to the third aspect, the other tubular member of the two tubular members is an engine body of the gas turbine engine, and one of the tubular members is Since the duct is connected to the exhaust side of the engine body, even if a composite material with a low coefficient of thermal expansion is used for the duct on the exhaust side of the engine body that is hot, the difference in the coefficient of thermal expansion from the engine body side Deformation and breakage caused by the above can be prevented. Further, even a composite material which is difficult to manufacture in a complicated shape can be formed in a relatively simple shape, which facilitates manufacturing.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of a jet engine according to a first embodiment of a tubular member joint structure according to the present invention.

FIG. 2 is a cross-sectional view before a thermal expansion showing a joint structure between an engine body and a bypass duct in the first embodiment of the joint structure of the tubular member according to the present invention.

FIG. 3 is a cross-sectional view after thermal expansion showing a joint structure between an engine body and a bypass duct in the first embodiment of the joint structure of the tubular member according to the present invention.

FIG. 4 is a sectional view after thermal expansion showing a joint structure between an engine body and a bypass duct in a second embodiment of the joint structure of a tubular member according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Jet engine 2 Engine main body part (the other cylindrical member) 2a, 12a Main body side end part (end part of the other cylindrical member) 3 Bypass duct (one cylindrical member) 3a, 13a Duct side end part (one side) 5, 15 Nipping ring (Nipping member)

Claims (3)

[Claims] 1. A joint structure of two tubular members (2, 3) formed of materials having different coefficients of thermal expansion and connected at ends, wherein one of the two tubular members has a cylindrical shape. The end (3a) of the member (3) is sandwiched between the end (2a) of the other cylindrical member (2) and the holding member (5) fixed to the end of the other cylindrical member. The holding member is formed of the same material or a material having substantially the same coefficient of thermal expansion as the other cylindrical member, and an end of the one cylindrical member is bent along a direction intersecting an axis. A joint structure for a cylindrical member. 2. An end (3) of said one cylindrical member (3).
2. The joint structure for a tubular member according to claim 1, wherein in (a), the wall thickness is set to gradually increase toward the tip. 3. The other tubular member of the two tubular members is an engine body (3) of the gas turbine engine (1), and one of the tubular members is an exhaust side of the engine body. The joint structure for a tubular member according to any one of claims 1 to 3, wherein the duct (2) is connected to the duct.