A bolt connection structure suitable for power turbine casing

Abstract

The present application belongs to the field of aero-engine technology, and particularly relates to a bolt connection structure suitable for a power turbine casing, a power turbine casing, and a plurality of segmented power turbine outer rings mounted on the inner wall surface of the power turbine casing; wherein, the inner wall surface of the power turbine casing is provided with a plurality of annular stoppers and a plurality of annular mounting platforms; the annular mounting platform is composed of a ring having a plurality of circumferentially distributed U-shaped through grooves for accommodating bolts, the opening of the U-shaped through grooves faces the inner side of the power turbine casing, and the end face of the U-shaped through grooves has a U-shaped groove for accommodating bushing nuts; the power turbine outer ring has an annular groove clamped in the annular stopper and a mounting edge, the mounting edge has a plurality of through holes, the bolts pass through the through holes and are connected with the U-shaped through grooves and bushing nuts, so that the mounting edge is fixedly connected to the annular mounting platform.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine technology, and in particular relates to a bolt connection structure suitable for a power turbine casing. Background Art

[0002] Typically, the turbine casing is designed as a two-layer structure: a full-ring outer casing and a segmented outer ring inner casing. A thermal insulation layer is placed between the turbine outer ring and the casing, shielding it from direct air contact. This prevents heat from dissipating from the outer ring into the casing. This layer also slows the outer ring's temperature response during transient conditions, controlling the thermal response between the casing and rotor. This also separates the casing's heat- and stress-bearing components, allowing the cooler outer casing to bear the stress.

[0003] The power turbine outer ring is an important part of the power turbine casing assembly. Its function is to connect the power turbine casing with the guide blades. As the carrier of the honeycomb in the sealing structure, the power turbine outer ring and the power turbine casing are usually connected by a hook connection on one side and a stopper and bolt connection on the other side. The structure is as follows Figure 1 Therefore, the reliability of the low-pressure turbine outer ring and guide vane positioning structure is of great significance to it, and the bolt connection structure is of great value to it.

[0004] The outer ring of the power turbine is installed on the casing by screws. Since the outer ring is a segmented structure, it is necessary to improve the processing accuracy and reduce the matching clearance of the bolt holes and mating surfaces to ensure assembly. On the one hand, due to the structural space layout limitations of the power turbine casing, bolt connection requires the processing of bolts / threaded holes on the casing arms, and the processing of bolts / bolt holes requires sufficient radial avoidance of the other arms to ensure that the tool can reach. Figure 2 On the other hand, for multi-stage power turbine casings, the axial length is large, and bolt / thread hole processing usually requires the use of extended toolholders, which is difficult to process. In addition, the processing requires a lot of cutting and the processing accuracy is low. Summary of the Invention

[0005] In order to solve the above problems, the present application provides a bolt connection structure suitable for a power turbine casing, comprising:

[0006] A power turbine casing and a plurality of segmented power turbine outer rings mounted on the inner wall surface of the power turbine casing;

[0007] The inner wall surface of the power turbine casing is provided with a plurality of annular stoppers and a plurality of annular mounting platforms; the annular mounting platform is formed into a ring having a plurality of circumferentially distributed U-shaped through grooves for accommodating bolts, the openings of the U-shaped through grooves facing the inner side of the power turbine casing, and the end surfaces of the U-shaped through grooves have U-shaped grooves for accommodating bushing nuts;

[0008] The outer ring of the power turbine has an annular groove clamped in the annular stop and a mounting edge. The mounting edge has multiple through holes. Bolts pass through the through holes and are connected to the U-shaped through grooves and bushing nuts to fix the mounting edge to the annular mounting platform.

[0009] Preferably, the bottom contour lines of the U-shaped through groove and the U-shaped groove are both semicircular, and the groove wall contour lines of the U-shaped through groove and the U-shaped groove are both tangents of the semicircular bottom.

[0010] Preferably, the annular mounting platform is axially protruded at a radial position of the U-shaped through groove to form an annular positioning boss, and the mounting edge is axially recessed at a radial position of the through hole to form an annular positioning groove for accommodating the annular positioning boss.

[0011] Preferably, the radius of the groove bottom contour line of the U-shaped through groove is smaller than the groove bottom contour line of the semicircular U-shaped groove.

[0012] Preferably, the center of the groove bottom contour line of the U-shaped through groove is concentric with the center of the groove bottom contour line of the U-shaped groove.

[0013] Preferably, the U-shaped through groove and the U-shaped groove are formed by radial milling.

[0014] Preferably, the bushing nut and the bolt are prevented from rotating by a locking plate, and the bushing nut is a U-shaped structure.

[0015] Preferably, the U-shaped groove has a limiting boss for limiting the axial displacement of the bushing nut.

[0016] The advantages of this application include: this application adopts a "U" groove bolt connection form, the groove is processed on the casing by a radial milling cutter, and the U-shaped nut is assembled to cooperate with the power turbine outer ring to realize the positioning of the bushing nut, so that the bolt can be screwed in smoothly, and at the same time, it can ensure that the nut and the casing are axially fitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a preferred embodiment of the present application and is applicable to a bolt connection structure of a power turbine casing;

[0018] Figure 2 This is a schematic diagram of a U-shaped groove in a preferred embodiment of the present application;

[0019] Figure 3 This is a schematic diagram of the outer ring assembly;

[0020] Figure 4 This is a schematic diagram of the outer ring assembly structure. DETAILED DESCRIPTION

[0021] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0022] In addition, unless otherwise defined, the technical or scientific terms used in the description of this application should have the ordinary meanings understood by those of ordinary skill in the art to which this application belongs. The words "upper," "lower," "left," "right," "center," "vertical," "horizontal," "inner," and "outer" used in the description of this application are only used to indicate relative directions or positional relationships, and do not imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. Therefore, they should not be understood as limitations on this application. The words "first," "second," "third," and similar terms used in the description of this application are used only for descriptive purposes to distinguish different components and should not be understood to indicate or imply relative importance. The words "one," "an," or "the" used in the description of this application should not be understood as absolute limitations on quantity, but should be understood as meaning the presence of at least one. The words "include" or "comprises" used in the description of this application mean that the element or object listed before the word includes the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0023] In addition, it should be noted that, unless otherwise clearly stipulated and limited, the words "install", "connect", "connect" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection between two components. Technical personnel in the field can understand their specific meanings in this application according to the specific circumstances.

[0024] like Figures 1-4 As shown, the present application provides a bolt connection structure suitable for a power turbine casing, wherein a groove is machined on the casing by a radial milling cutter, and a U-shaped nut is assembled to cooperate with the outer ring of the power turbine to realize the positioning of the bushing nut, so that the bolt can be screwed in smoothly, and at the same time, the nut can be ensured to fit axially with the casing, including;

[0025] A power turbine casing 1 and a plurality of segmented power turbine outer rings 2 mounted on the inner wall surface of the power turbine casing 1;

[0026] The inner wall surface of the power turbine casing 1 is provided with a plurality of annular stoppers 12 and a plurality of annular mounting platforms. The annular mounting platform is formed into a ring having a plurality of circumferentially distributed U-shaped through grooves 6 for accommodating bolts 3. The openings of the U-shaped through grooves 6 face the inner side of the power turbine casing 1. The end surfaces of the U-shaped through grooves 6 are provided with U-shaped grooves 5 for accommodating bushing nuts 4.

[0027] The outer ring 2 of the power turbine has an annular groove that is clamped in the annular stop 12 and a mounting edge. The mounting edge has multiple through holes. The bolts 3 pass through the through holes and are connected to the U-shaped through grooves 6 and the bushing nuts 4, so that the mounting edge is fixedly connected to the annular mounting platform. Each bolt corresponds to a U-shaped groove 5 and a U-shaped through groove 6, which are all realized by radial milling. The U-shaped through groove 6 is only used to avoid the bolts 3, and the U-shaped groove 5 is used to position the bushing nuts 4.

[0028] The bushing nut 4 is a U-shaped structure, and its U-section is the same as the U-shaped groove 5 section, but the size is slightly smaller than the U-shaped groove 5 to ensure the assembly of the bushing nut 4 and allow a small range of free movement.

[0029] In some optional embodiments, the power turbine outer ring 2 is a sector-shaped segmented structure, each outer ring is connected by two bolts and positioned in the low-pressure turbine casing by a radial slot. When assembling the bushing nut 4, first install the two bushing nuts used to connect the single outer ring into the U-shaped groove 5, and then install the power turbine outer ring to achieve the positioning of the bushing nut. Figure 3 ;

[0030] In some optional embodiments, the bottom contour lines of the U-shaped through groove 6 and the U-shaped groove 5 are both semicircular, and the groove wall contour lines of the U-shaped through groove 6 and the U-shaped groove 5 are both tangents of the semicircular bottom.

[0031] In some optional embodiments, the annular mounting platform axially protrudes at the radial position of the U-shaped through groove 6 to form an annular positioning boss, and the mounting edge is axially recessed at the radial position of the through hole to form an annular positioning groove for accommodating the annular positioning boss.

[0032] In some optional embodiments, the radius of the groove bottom contour line of the U-shaped through groove 6 is smaller than the semicircular groove bottom contour line of the U-shaped groove 5 .

[0033] In some optional embodiments, the center of the groove bottom contour line of the U-shaped through groove 6 is concentric with the center of the groove bottom contour line of the U-shaped groove 5 .

[0034] In some optional embodiments, the U-shaped through groove 6 and the U-shaped groove 5 are formed by radial milling.

[0035] In some optional embodiments, after the bushing nut 4 is positioned, there is still a small range of circumferential and radial movement. At this time, the bushing nut 4 is equivalent to a loose nut, and the bolt can be screwed in smoothly while ensuring that the nut and the casing are axially aligned. Finally, a locking plate is used to prevent the bolt from rotating. Figure 4 .

[0036] In some optional embodiments, the U-shaped groove 5 has a limiting boss for limiting the axial displacement of the bushing nut 4 .

[0037] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A bolt connection structure suitable for a power turbine casing, characterized in that: include; A power turbine casing (1) and a plurality of fan-shaped segmented power turbine outer rings (2) mounted on the inner wall surface of the power turbine casing (1), wherein the power turbine outer ring (2) is circumferentially mounted on the power turbine casing (1) to form a complete ring; The inner wall surface of the power turbine casing (1) is provided with a plurality of annular stoppers (12) and a plurality of annular mounting platforms; the annular mounting platform is formed into a ring with a plurality of circumferentially distributed U-shaped through grooves (6) for accommodating bolts (3); the opening of the U-shaped through groove (6) faces the inner side of the power turbine casing (1); and the end surface of the U-shaped through groove (6) is provided with a U-shaped groove (5) for accommodating a bushing nut (4); The power turbine outer ring (2) has an annular groove clamped in the annular stop (12) and a mounting edge, the mounting edge has a plurality of through holes, and bolts (3) pass through the through holes and are connected to the U-shaped through groove (6) and the bushing nut (4), so that the mounting edge is fixedly connected to the annular mounting platform; The bottom contour lines of the U-shaped through groove (6) and the U-shaped groove (5) are both semicircular, and the groove wall contour lines of the U-shaped through groove (6) and the U-shaped groove (5) are both tangent lines of the semicircular bottom; the annular mounting platform axially protrudes at the radial position of the U-shaped through groove (6) to form an annular positioning boss, and the mounting edge is axially recessed at the radial position of the through hole to form an annular positioning groove for accommodating the annular positioning boss; The radius of the groove bottom contour line of the U-shaped through groove (6) is smaller than the semicircular groove bottom contour line of the U-shaped groove (5); and the center of the groove bottom contour line of the U-shaped through groove (6) is concentric with the center of the groove bottom contour line of the U-shaped groove (5).

2. The bolt connection structure for a power turbine casing according to claim 1, wherein: The U-shaped through groove (6) and the U-shaped groove (5) are formed by radial milling.

3. The bolt connection structure for a power turbine casing according to claim 1, wherein: The bushing nut (4) and the bolt (3) are prevented from rotating by a locking plate.

4. The bolt connection structure for a power turbine casing according to claim 1, wherein: The U-shaped groove (5) has a limiting boss for limiting the axial displacement of the bushing nut (4).

5. The bolt connection structure for a power turbine casing according to claim 1, wherein: The bushing nut (4) is a U-shaped structure.

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