Turbine rear bearing casing and forming method thereof

Abstract

The turbine rear force-bearing casing capable of improving the forming quality of the vacuum electron beam welding process comprises a plurality of assembly units, wherein the assembly units comprise a plurality of fan-shaped sections; each fan-shaped section comprises an outer ring section, an inner ring section and a support plate for connecting the outer ring section and the inner ring section; the multiple fan-shaped sections are spliced to form a turbine rear force-bearing casing body, the outer ring sections of the adjacent fan-shaped sections are connected through welding seams, the inner ring sections of the adjacent fan-shaped sections are connected through welding seams, and an outer ring and an inner ring of the turbine rear force-bearing casing body are formed. The multiple assembling units further comprise end components, the end components comprise inner flow channel end components, the inner flow channel end components are connected with the ends of the inner rings, and for at least partial weld joint connection of the inner ring sections of the adjacent fan-shaped sections, the T-shaped structures causing wall thickness sudden change are partially or completely located on the inner flow channel end components. The weld is formed by vacuum electron beam welding. According to the forming method of the turbine rear force-bearing casing, the process of firstly forging and then welding is adopted, and the forming difficulty of the turbine rear force-bearing casing is reduced.

Description

Technical Field

[0001] The invention relates to a turbine rear bearing casing and a forming method thereof. Background Art

[0002] The turbine rear bearing case (hereinafter referred to as "rear case") of a turbofan engine can also be called the exhaust section bearing case. It is part of the engine bearing frame. On the one hand, it guides the gas from the low-pressure turbine to the tail nozzle and discharges it outside the engine. On the other hand, it fixes the engine fulcrum bearing and transfers the rotor load to the engine mounting section. The rear case generally includes an outer ring, an inner ring, a plurality of support plates and other structures. The high-temperature gas enters the tail nozzle section in the flow channel formed by the outer ring and the inner ring, and the inner ring and the outer ring are connected by a plurality of support plates. The rear fulcrum bearing seat is connected to the inner ring, and the load from the bearing seat is transferred to the support plate, the outer ring and the entire bearing system of the engine. The support plate between the inner and outer rings is generally a hollow thin-walled blade-shaped structure with oil pipes and ventilation pipes inside. In addition to bearing the load, the support plate also serves to isolate the oil pipes and air pipes from high temperatures.

[0003] There are generally two process approaches for manufacturing rear receivers: integral casting and split casting plus welding. The integral casting method refers to the one-time casting of the entire structure including the outer ring, inner ring, support plate, etc. The split casting plus welding method divides the integral receiver into multiple castings. The production cost of a single casting is low and the qualified rate is high. The castings are machined and welded into a whole. For small and medium-sized load-bearing receivers, the integral casting process is relatively easy to implement and has high structural reliability. For large-sized rear receivers with a diameter of more than 1.5m, the weight of the integral casting and the casting system is large, and the capacity of the melting and casting equipment is extremely high. In addition, since the minimum wall thickness of the receiver is 2mm, the overall wax mold strength is insufficient and the process stability is poor. Split casting divides the receiver into structures that are easy to cast and weld them into one. It is a relatively feasible process approach for large-sized rear receivers.

[0004] The applicant has proposed a solution that meets the above process requirements in the Chinese patent application with application number “202322353380.4” and name “Exhaust Section Load-Bearing Casing”, but further research is needed to improve the quality and reliability of the manufacturing process. Summary of the invention

[0005] An object of the present invention is to provide a turbine rear bearing casing so that its molding quality is improved.

[0006] Another object of the present invention is to provide a method for forming a turbine rear bearing casing, which adopts a process of forging first and then welding to reduce the difficulty of forming the turbine rear bearing casing.

[0007] According to one aspect of the present invention, a turbine rear bearing casing comprises a plurality of assembly units, wherein the plurality of assembly units comprise a plurality of fan-shaped segments; each of the fan-shaped segments comprises an outer ring segment, an inner ring segment and a support plate connecting the outer ring segment and the inner ring segment; the plurality of fan-shaped segments are spliced ​​into a turbine rear bearing casing body, and the outer ring segments and the inner ring segments of adjacent fan-shaped segments are respectively connected by welds to form an outer ring and an inner ring of the turbine rear bearing casing body; the plurality of assembly units further comprise end members, wherein the end members comprise an inner flow channel end member, and the inner flow channel end member is connected to the end of the inner ring, and for at least a portion of the weld connection of the inner ring segments of the adjacent fan-shaped segments, part or all of the T-shaped structure resulting in a sudden change in wall thickness is located on the inner flow channel end member; the weld is formed by vacuum electron beam welding.

[0008] In one embodiment, the inner ring section of the sector segment includes an inner ring wall and an inner cone wall, the inner ring wall is connected to the inner cone wall on the inner circumference side of the front end of the inner ring wall, and the front end of the inner ring wall terminates at the connection transition position between the inner ring wall and the inner cone wall at the weld connection of the inner ring sections of the two sector segments; the end member includes an inner flow channel front section; the inner flow channel front section includes an inner ring wall front section and a front connecting portion extending from the inner circumference side of the inner ring wall front section; the rear end of the inner ring wall front section is butted against the front end of the inner ring wall to provide a front section of the inner flow channel surface of the turbine rear bearing casing; the front connecting portion and the inner cone wall are connected by fasteners.

[0009] In one embodiment, at the weld connection of the inner ring segments of the two sector segments, the front end of the inner ring wall is a concave structure.

[0010] In one embodiment, the inner flow channel end member includes an inner flow channel rear section; the inner flow channel rear section includes an inner ring wall rear section and a rear connecting portion extending from the inner circumference of the inner ring wall rear section; the inner ring section of the fan-shaped section also includes an inner flow channel rear mounting edge, the inner ring wall is connected to the inner flow channel rear mounting edge on the inner circumference of the rear end of the inner ring wall, and the rear end of the inner ring wall terminates at the connection transition position between the inner ring wall and the inner flow channel rear mounting edge at the weld connection of the inner ring sections of the two fan-shaped sections; the front end of the inner ring wall rear section is butted with the rear end of the inner ring wall to provide the rear section of the inner flow channel surface of the turbine rear bearing casing; the rear connecting portion and the inner flow channel rear mounting edge are connected by fasteners.

[0011] In one embodiment, at the weld connection of the inner ring segments of the two sector segments, the rear end of the inner ring wall is a concave structure.

[0012] In one embodiment, the end member includes a front mounting edge of an outer flow channel, the front mounting edge of the outer flow channel includes a flange edge located on the outer peripheral side, the outer ring section includes an outer ring wall, and the rear end of the front mounting edge of the outer flow channel and the front end of the outer ring wall are connected by a weld.

[0013] In one embodiment, the end member further includes an outer channel rear mounting edge, the outer channel rear mounting edge includes a flange edge located on the outer peripheral side, and the front end of the outer channel rear mounting edge and the rear end of the outer ring wall are connected by a weld.

[0014] In one embodiment, the end member is a full annular structure or an annular structure formed by connecting a plurality of segments end to end.

[0015] In one embodiment, the segments are cast parts.

[0016] A method for forming a turbine rear bearing casing according to another aspect of the present invention comprises:

[0017] Providing a plurality of the sector segments and the end members, wherein the sector segments are formed by casting;

[0018] Splicing the fan-shaped segments to form a complete annular flow channel, and tightening them with tooling;

[0019] The vacuum electron beam welding process is used to weld the weld of the inner flow channel first, and then the weld of the outer flow channel. After the inner flow channel is welded, the outer flow channel will produce a certain deformation. The outer flow channel is corrected in one step by the tooling to ensure that the gap and misalignment at the docking position are within the allowable range of the welding process;

[0020] The end member and the end of the outer ring or the inner ring are connected to form a complete turbine rear bearing casing.

[0021] According to an embodiment of the present invention, the integral frame is formed by vacuum electron beam welding, resulting in that part or all of the T-shaped structure with a sudden change in wall thickness is located at the end member, so that the weld between adjacent fan-shaped segments is suitable for the electron beam welding process, thereby improving the forming quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0023] Figure 1 It is a three-dimensional picture of the turbine rear bearing casing;

[0024] Figure 2 This is the front view of the turbine rear bearing casing;

[0025] Figure 3 It is a cross-sectional view of the turbine rear bearing casing;

[0026] Figure 4 It is a three-dimensional diagram of the fan-shaped segment;

[0027] Figure 5 It is a schematic diagram of the incident angle of electron beam welding of adjacent sectors at the front end of the inner flow channel;

[0028] Figure 6 is a schematic diagram of the incident angles of electron beam welding of adjacent sector segments at the rear end of the inner flow channel;

[0029] Figure 7 is a schematic diagram of the incident angles of electron beam welding of adjacent sectors in the outer flow channel;

[0030] Figure 8 It is a partial view of the inner ring section of the sector;

[0031] Fig. 9 It is a schematic diagram of the connection between the front section of the inner flow channel and the inner ring section;

[0032] Fig.10 It is a schematic diagram of the connection between the rear end of the inner flow channel and the inner ring section;

[0033] Fig.11 It is a cross-sectional view of the front mounting edge of the outer flow channel;

[0034] Fig.12 It is a cross-sectional view of the rear mounting edge of the outer flow channel;

[0035] Fig.13 It is a cross-sectional view of a sector as a pair of proportions. DETAILED DESCRIPTION

[0036] Reference will now be made in detail to embodiments of the present invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided to explain the present invention, not to limit the present invention. In fact, it will be apparent to those skilled in the art that various modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature illustrated or described as part of one embodiment may be used together with another embodiment to produce yet another embodiment. Therefore, the present invention is intended to cover these modifications and variations within the scope of the appended claims and their equivalents.

[0037] As used herein, the terms "front" and "rear" refer to the relative directions of fluid flow in a fluid path in a flow channel of a turbine rear bearing case. For example, "front" refers to the direction from which the fluid flows, and "rear" refers to the direction toward which the fluid flows.

[0038] The "turbine rear bearing casing" is located behind the low-pressure turbine in a turbofan engine or gas turbine. It guides the low-pressure turbine outlet gas to the tail nozzle and fixes the components of the rear pivot bearing.

[0039] Electron beam welding or vacuum electron beam welding is a process that uses a high-energy electron beam to bombard the metal surface in a vacuum to melt the workpiece and weld it.

[0040] Figure 1 and Figure 2 An embodiment of a turbine rear bearing casing according to the present invention is shown, which comprises a plurality of assembly units, wherein the plurality of assembly units comprises a plurality of sectors 1 , 2 , 4 . Figure 4 shows a sector, which corresponds approximately to Figure 2 The sector segment 2 in the figure can also be understood by reference to other sector segments. Each sector segment 1, 2, or 4 includes an outer ring segment 31, an inner ring segment 32, and a support plate 33 connecting the outer ring segment 31 and the inner ring segment 32. Segment 1 includes three support plates 33, and three lifting devices are provided on the outer ring segment 31. An example of the lifting device is a lifting lug. The two sector segments 2 are symmetrically divided into four support plates 33. Segment 4 includes three support plates 33. If the lifting lug is not considered, sector segment 1 and sector segment 4 are symmetrical structures to each other. The figure illustrates a load-bearing casing with 14 support plates, but the implementation of the present invention is not limited to this. For example, a sector segment of a load-bearing casing with 15 support plates may include a sector segment with 3 support plates and three sector segments with 4 support plates. In another embodiment, the division of the sector segments may be that at least one sector segment includes at least two support plates. As Figure 2 As shown, adjacent fan-shaped segments 1, 2, or 4 are connected by welds 11, 12, 13, 14, 15, 16, 17, and 18 to form the outer ring and inner ring of the turbine rear bearing casing body, and the welds are welds formed by vacuum electron beam welding. Compared with other welds, vacuum electron beam welds have narrow width, deep welding depth, large depth-to-width ratio, and small welding deformation. Compared with the traditional segmented exhaust section bearing casing, the number of welds is reduced, and the quality and reliability of the manufacturing process are improved. Too many welds bring higher risks. Even if welding quality problems are found during the process, the subsequent repair welding process requires a lot of manual operation and repeated inspections, which will reduce production efficiency to a certain extent. Therefore, the use of vacuum electron beam welds for connection can provide a reasonable segmented structural form of the bearing casing, control the number of welds and welding positions as much as possible, improve the reliability and efficiency of the process method, and improve the reliability of the service of parts.

[0041] like Figure 1 and Figure 2 As shown, the plurality of assembly units further include an end member, and the end member is connected to the end of the outer ring or the inner ring. The "end of the outer ring or the inner ring" refers to the end in terms of the axial direction of the turbine rear bearing casing. The "inner flow channel" is the flow channel surface provided by the inner ring of the turbine rear bearing casing. The "outer flow channel" is the flow channel surface provided by the outer ring of the turbine rear bearing casing. Figure 3Four end components are shown, including the inner flow channel front section 7, the inner flow channel rear section 8, the outer flow channel front mounting edge 5, and the outer flow channel rear mounting edge 6. The inner flow channel front section 7 and the inner flow channel rear section 8 are the inner flow channel end components. For at least part of the weld connection of the adjacent fan-shaped segments, the T-shaped structure that causes the wall thickness to change suddenly is partially or completely located at the end component. Figure 3 For example, the front mounting edge 5 of the outer flow channel and the outer ring are on both sides of the weld 19, connected by the weld 19, the T-shaped structure is divided on one side of the front mounting edge 5 of the outer flow channel, and there is no T-shaped structure at the front end of the outer ring. Similarly, the rear mounting edge 6 of the outer flow channel and the outer ring are on both sides of the weld 20, connected by the weld 20, the T-shaped structure is divided on one side of the rear mounting edge 6 of the outer flow channel, and there is no T-shaped structure at the rear end of the outer ring. Fig. 9 More clearly shown Figure 3 The assembly method between the front section 7 of the inner flow channel and the inner ring, Fig.10 More clearly shown Figure 3 The assembly method between the rear section 8 of the inner flow channel and the inner ring. Fig. 9 As shown, the rear end of the inner flow channel front section 7 is spliced ​​with the front end of the outer ring to form a T shape, and the T shape is divided into an angled portion t1 and a wing portion t2, the angled portion t1 is located at the front end of the outer ring, and the wing portion t2 is located at the rear end of the inner flow channel front section 7. Similarly, Fig.10 In the embodiment, the front end of the rear section 8 of the inner flow channel and the rear end of the outer ring are spliced ​​into a nearly T-shaped structure, and the nearly T-shaped structure here is divided into an angled portion t3 and a wing portion t4, the angled portion t3 is located at the rear end of the outer ring, and the wing portion t4 is located at the front end of the rear end 8 of the inner flow channel. "T-shaped structure portion" means that the portion is no longer a T-shaped structure. Figure 5 , Figure 6 and Figure 7 The incident angles of adjacent sectors for electron beam welding are shown. Since the T-shaped structure that causes the wall thickness to change suddenly is partially or completely located at the end member, a large change in the wall thickness along the incident direction of the electron beam welding is avoided. The relatively uniform wall thickness is conducive to improving the welding quality of electron beam welding and reducing welding defects. As a comparative example, Fig.13 When the T-shaped structure at A shown is electron beam welded to two adjacent sectors, no matter how the electron beam direction is selected, there will be a large change in wall thickness, which is easy to cause welding defects. It can be understood that the division method of the end member and the sector at any of the above four end members is beneficial to improving the welding quality of electron beam welding. Accordingly, the implementation of any one or a combination of multiple of the above four end members belongs to the embodiments of the present invention.

[0042] like Figure 3 , Figure 8 , Fig. 9As shown, the inner ring segment 32 of the sector segment includes an inner ring wall 321 and an inner cone wall 322. The inner ring wall 321 is connected to the inner cone wall 322 at the inner peripheral side of the front end of the inner ring wall 321, and the front end of the inner ring wall 321 terminates at the connection transition position between the inner ring segments 32 of two adjacent sector segments. For example, the front end of the inner ring wall 321 does not extend to the left and exceed the connection transition position between the inner ring wall 321 and the inner cone wall 322, which ensures that the T-shaped structure is substantially separated and reduces the large change in wall thickness. One implementation method of terminating the front end of the inner ring wall 321 at the connection transition position between the inner ring wall 321 and the inner cone wall 322 at the weld connection is as follows: Fig. 9 As shown, the front end of the inner ring wall 321 has a Figure 8 The recessed structure 323 is shown, so that the front end of the inner ring wall 321 does not need to be retracted to the right as a whole, and the wing t2 is similar to a convex piece and is embedded in the recessed structure 323. The function of the wing t2 is to prevent the opening caused by the recessed structure 323 from being too large and allowing the flow channel gas to enter the outer cavity. In addition, by controlling the pressure of each cavity in the rear casing of the engine, it should be required that the inner cavity pressure is greater than the pressure in the flow channel, which can also avoid the problem of gas entering the inner cavity.

[0043] The inner flow channel front section 7 includes an inner ring wall front section 71 and a front connecting portion 72 extending from the inner circumference of the inner ring wall front section 71. Fig. 9 The horizontally extending portion, the front connecting portion 72 is Fig. 9 The vertically extending part, the aforementioned wing portion t2 belongs to a part of the front section of the inner ring wall.

[0044] The rear end of the inner ring wall front section 71 is butted against the front end of the inner ring wall 321 to provide the front section of the inner flow path surface of the turbine rear bearing casing. Figure 3 and Fig. 9 The middle is the right end.

[0045] The front connection part and the inner cone wall 322 are connected by a fastener 91. In the embodiment shown in the figure, except for the recessed structure 323, at the right end of the inner ring wall front section 7, the inner ring wall front section and the front connection part are in a right angle shape, and accordingly, the connection transition position of the inner ring wall 321 and the inner cone wall 322 is also in a right angle shape, so that the two right angles can be in contact and fit, and only a gap is maintained at the recessed structure 323. The aforementioned fasteners can be bolts and nuts.

[0046] The inner flow channel front section 7 can be a full ring structure or a ring structure formed by connecting segments end to end. An example of the front connecting portion 72 is a lug extending from the inner circumference of the inner ring wall front section 71 .

[0047] Continue to refer to Figure 3 , Figure 8 , Fig. 9, the inner annular wall 321 is connected to the inner flow channel mounting edge 325 at the inner peripheral side of the rear end of the inner annular wall 321, and the rear end of the inner annular wall 321 terminates at the connection transition position between the inner annular segments 32 of the two adjacent sector segments. For example, the rear end of the inner annular wall 321 does not extend to the right and exceed the connection transition position between the inner annular wall 321 and the inner cone wall 322, which can ensure that the T-shaped structure is substantially separated and reduce the large change in wall thickness. One implementation method of the rear end of the inner annular wall 321 at the weld connection terminates at the connection transition position between the inner annular wall 321 and the inner flow channel mounting edge 325 is as follows Fig. 9 As shown, the rear end of the inner ring wall 321 has a Figure 8 The recessed structure 326 is shown, so that the rear end of the inner annular wall 321 does not need to be retracted to the right as a whole, and the wing portion t4 is similar to a convex piece and embedded in the recessed structure 326 .

[0048] The inner flow channel rear section 8 includes an inner ring wall rear section 81 and a rear connecting portion 82 extending from the inner circumference of the inner ring wall rear section 81. Fig. 9 The horizontally extending portion of the rear connecting portion 82 is Fig. 9 The vertically extending portion, the aforementioned wing portion t4 belongs to a part of the rear section of the inner ring wall.

[0049] The front end of the inner ring wall rear section 81 is butted against the rear end of the inner ring wall 321 to provide the rear section of the inner flow path surface of the turbine rear bearing casing. Figure 3 and Fig. 9 The middle is the left end.

[0050] The rear connection part 82 and the inner flow channel mounting edge 325 are connected by a fastener 92. In the embodiment shown in the figure, except for the recessed structure 326, at the left end of the inner ring wall rear section 7, the inner ring wall rear section and the rear connection part are in a right angle shape, and accordingly, the connection transition position of the inner ring wall 321 and the inner flow channel mounting edge 325 is also roughly in a right angle shape, so that the two right angles can contact and fit, and only a gap is maintained at the recessed structure 326. The aforementioned fasteners can be bolts and nuts.

[0051] The inner flow channel rear section 8 can be a full ring structure or a ring structure formed by connecting segments end to end. An example of the rear connecting portion 82 is a lug extending from the inner peripheral side of the inner ring wall rear section 81 .

[0052] like Figure 3 and Fig.11As shown, the outer flow channel front mounting edge 5 includes a flange edge 51 located on the outer peripheral side, and the outer ring segment 31 has an outer ring wall as its main structure in addition to the aforementioned lifting device. The rear end of the outer flow channel front mounting edge 5 and the outer ring wall or the front end of the outer ring segment 31 are connected by a weld. The outer peripheral wall of the outer ring segment 31 has no substantial wall thickness mutation, so the welding quality is easy to control.

[0053] like Figure 3 and Fig.12 As shown, the outer runner rear mounting edge 6 includes a flange edge 61 located on the outer peripheral side, and the front end of the outer runner rear mounting edge 61 and the rear end of the outer ring wall are connected by a weld. This also makes the outer peripheral wall of the outer ring section 31 have no substantial wall thickness mutation, so the welding quality is easy to control.

[0054] An example of a molding method for the exhaust section load-bearing casing is described below.

[0055] Each of the four segments is formed by casting. The segment with three and four support plates and the segment with three support plates with lifting ears on the outer ring surface are all completed by casting parts separately.

[0056] For a single part, six side surfaces are processed before welding (such as Figure 4 There are 6 faces (a, b, c, d, e, f) in the middle. After processing faces a, b, c, d, faces a and b, faces c and d can be spliced ​​between two fan-shaped segments. After four pieces are spliced, a complete circulation channel is formed. The margins are reserved for faces e and f, and are removed after welding into a complete circle.

[0057] The vacuum electron beam welding process is used to weld the weld of the inner flow channel first, and then the weld of the outer flow channel. After the inner flow channel is welded, the outer flow channel will produce a certain deformation. The outer flow channel is corrected in one step by the tooling to ensure that the gap and misalignment at the docking position are within the allowable range of the welding process. For example, before welding four fan-shaped segments into a full circle, the front installation edge 5 and the rear installation edge 6 can be used to tighten them. The adjacent two pieces are connected to form a full circle by vacuum electron beam welding. The welds between the fan-shaped segments are as follows: Figure 2 As shown, weld seams 11, 12, 13, 14, 15, 16, 17, 18 are shown.

[0058] Machining to remove the excess on the front and rear transition edges of the full ring frame (such as Figure 4 The roundness of the front and rear transition sections e and f of the full-circle frame after welding is measured, and the places with large deviations are adjusted through fixed fixtures to meet the shape requirements of the front and rear installation edges when welding.

[0059] The excess material at e and f is removed by machining to make the full-circle frame ready for welding with the mounting edge. The front and rear mounting edges are welded to the full-circle frame by vacuum electron beam welding. Surface e on the frame is welded to surface h of the front mounting edge, and surface f is welded to surface i of the rear mounting edge.

[0060] After welding, the frame is subjected to stress relief heat treatment to release welding stress. Then the exhaust section load-bearing casing segment welding manufacturing process is completed.

[0061] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. The turbine rear bearing casing is characterized by: comprising a plurality of assembly units, wherein the plurality of assembly units comprises a plurality of fan-shaped segments; Each of the fan-shaped segments includes an outer ring segment, an inner ring segment, and a support plate connecting the outer ring segment and the inner ring segment; The plurality of sector segments are spliced ​​into a turbine rear bearing casing body, and the outer ring segments and the inner ring segments of adjacent sector segments are respectively connected by welds to form an outer ring and an inner ring of the turbine rear bearing casing body; The plurality of assembly units further include end members, the end members including inner flow channel end members, the inner flow channel end members being connected to the ends of the inner rings, For at least a portion of the weld connection of the inner ring segments of the adjacent sectors, the T-shaped structure causing the sudden change in wall thickness is partially or completely located at the inner flow channel end member; The weld is formed by vacuum electron beam welding.

2. The turbine rear bearing casing according to claim 1, characterized in that: The inner ring section of the sector segment comprises an inner ring wall and an inner cone wall, wherein the inner ring wall is connected to the inner cone wall at the inner circumference of the front end of the inner ring wall, and the front end of the inner ring wall terminates at a connection transition position between the inner ring wall and the inner cone wall at the weld connection of the inner ring sections of the two sector segments; The inner flow channel end member includes an inner flow channel front section; The front section of the inner flow channel includes a front section of an inner ring wall and a front connecting portion extending from the inner circumference of the front section of the inner ring wall; The rear end of the front section of the inner annular wall is butted against the front end of the inner annular wall to provide a front section of the inner flow passage surface of the turbine rear bearing casing; The front connecting portion and the inner cone wall are connected via a fastener.

3. The turbine rear bearing casing according to claim 2, characterized in that: At the weld connection of the inner ring segments of the two sector segments, the front end of the inner ring wall is a concave structure.

4. The turbine rear bearing casing according to claim 1, characterized in that: The inner flow channel end member includes an inner flow channel rear section; The rear section of the inner flow channel includes an inner ring wall rear section and a rear connecting portion extending from the inner circumference of the inner ring wall rear section; The inner ring section of the sector segment further comprises an inner flow channel rear mounting edge, the inner ring wall is connected to the inner flow channel rear mounting edge at the inner circumference of the rear end of the inner ring wall, and the rear end of the inner ring wall terminates at a connection transition position between the inner ring wall and the inner flow channel rear mounting edge at the weld connection of the inner ring sections of the two sector segments; The front end of the rear section of the inner annular wall is butted against the rear end of the inner annular wall to provide a rear section of the inner flow passage surface of the turbine rear bearing casing; The rear connecting portion and the rear mounting edge of the inner flow channel are connected via a fastener.

5. The turbine rear bearing casing according to claim 4, characterized in that: At the weld connection of the inner ring segments of the two sector segments, the rear end of the inner ring wall is a concave structure.

6. The turbine rear bearing casing according to claim 1, characterized in that: The end member also includes an outer flow channel front mounting edge, The front mounting edge of the outer flow channel includes a flange edge located on the outer peripheral side, The outer ring segment comprises an outer ring wall, The rear end of the front mounting edge of the outer flow channel and the front end of the outer ring wall are connected by a weld.

7. The turbine rear bearing casing according to claim 6, characterized in that: The end member also includes an outer flow channel rear mounting edge, The rear installation edge of the outer flow channel includes a flange edge located on the outer peripheral side, The front end of the rear installation edge of the outer flow channel and the rear end of the outer ring wall are connected by a weld.

8. The turbine rear bearing casing according to any one of claims 1 to 7, characterized in that: The end member is a full ring structure or a ring structure formed by connecting multiple segments end to end.

9. The turbine rear bearing casing according to any one of claims 1 to 7, characterized in that: The sector is a cast part.

10. The method for forming a turbine rear bearing casing according to any one of claims 1 to 9, characterized in that: Providing a plurality of the sector segments and the end members, wherein the sector segments are formed by casting; Splicing the fan-shaped segments to form a complete annular flow channel, and tightening them with tooling; The vacuum electron beam welding process is used to weld the weld of the inner flow channel first, and then the weld of the outer flow channel. After the inner flow channel is welded, the outer flow channel will produce a certain deformation. The outer flow channel is corrected in one step by the tooling to ensure that the gap and misalignment at the docking position are within the allowable range of the welding process; The end member and the end of the outer ring or the inner ring are connected to form a complete turbine rear bearing casing.

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