CN220909825U - Sealing, pressurizing and air-entraining structure for bearing cavity of power turbine of gas turbine - Google Patents

Abstract

The utility model discloses a sealing, pressurizing and air-entraining structure for a bearing cavity of a power turbine of a gas turbine, belongs to the technical field of gas turbines, and aims to solve the problem that the air-entraining loss part of the gas turbine is functional. Including the turbine axle, the turbine axle is equipped with the axle inner chamber, the shaft coupling cup joints the rear portion at the turbine axle, form the second cavity between shaft coupling and the turbine axle, the interior turnover movable fit of the outer Zhou Heqi way components of shaft coupling is equipped with first cavity on the gas circuit component, the gas seal cup joints the front portion at the turbine axle, the periphery processing of gas seal has the fifth ring channel, the periphery and the second seal cover normal running fit of gas seal, the second rim plate cup joints on the turbine axle, form the rim plate back cavity between second rim plate and the bearing housing, first air supply pipe communicates with first cavity in proper order, the second cavity, the axle inner chamber, fifth ring channel and rim plate back cavity. The utility model provides sealing pressurizing air for the bearing cavity, and cools the turbine shaft and the wheel disc along the way, thereby saving the consumption of the pressurizing air.

Description

Sealing, pressurizing and air-entraining structure for bearing cavity of power turbine of gas turbine

Technical Field

The utility model belongs to the technical field of gas turbines, and particularly relates to a sealing, pressurizing and air-entraining structure for a bearing cavity of a power turbine of a gas turbine.

Background

The main function of the lubricating oil seal of the bearing cavity of the gas turbine is to effectively isolate the bearing cavity of the rotor system of the gas turbine from the air flow environment of the gas turbine, protect the bearing and lubricating oil from the damage of the air flow path environment and prevent the lubricating oil from leaking. The air is generally led from a proper position of the compressor to pressurize the lubricating oil for sealing, so that the lubricating oil is prevented from leaking.

The lubricating oil seal of general bearing chamber is pressurized, needs complicated bleed air and sealing system, has increased the complexity of engine weight and system, and bleed air effect is single simultaneously, and bleed air loses partly and does the functional capacity after compressing as seal gas from the compressor use, has also reduced unit overall efficiency. Therefore, the air consumption is reduced and the efficiency of the unit can be improved while the sealing pressurization effect is ensured.

Disclosure of utility model

The utility model aims to provide a sealing, pressurizing and air-entraining structure for a bearing cavity of a power turbine of a gas turbine, so as to solve the problem that after the air-entraining of the gas turbine is used as sealing air, the lost part is used as functional force. The technical scheme adopted by the utility model is as follows:

The utility model provides a gas turbine power turbine bearing chamber seal pressure boost bleed air structure, includes the turbine axle, and bearing housing, rectifier support and lining cup joint on the turbine axle from inside to outside in proper order, and bearing housing and turbine axle are respectively through preceding support bearing and back support bearing rotation connection;

The gas path component comprises a first sealing sleeve structure and a front annular baffle structure which are sleeved inside and outside, a rear annular baffle is sleeved on the first sealing sleeve structure, the outer end of the front annular baffle structure is connected with the rear end of the bearing shell, the periphery of the rear annular baffle is in sealing connection with the periphery of the front annular baffle structure, a first cavity is formed between the front annular baffle structure and the rear annular baffle, and a plurality of first through holes are formed in the first sealing sleeve structure between the front annular baffle structure and the rear annular baffle;

The coupler is sleeved at the rear end of the turbine shaft, a first stepped part, a first shaft shoulder, a first annular groove and a first comb tooth sealing structure are sequentially machined backwards in the outer Zhou Congqian of the coupler, a first sealing ring is sleeved on the first stepped part, a first baffle ring is sleeved on the coupler, the first baffle ring and the first shaft shoulder are respectively clamped at two sides of the first sealing ring, the outer periphery of the first comb tooth sealing structure is in close rotating fit with the inner periphery of the first sealing sleeve structure, the outer periphery of the first sealing ring is in rotating seal fit with the inner periphery of the first sealing sleeve structure, a second annular groove is machined in the inner periphery of the coupler, a third annular groove is machined in the turbine shaft, the second annular groove and the third annular groove are combined to form a second cavity, a plurality of second through holes are machined in the coupler, and the first annular groove and the second cavity are communicated through the second through holes;

The air seal and the second baffle ring are sleeved at the front part of the turbine shaft, the air seal, the second baffle ring and the inner ring of the front support bearing are propped against each other in sequence, the outer Zhou Congqian of the air seal is provided with a second comb tooth sealing structure, a fifth annular groove, a second shoulder and a second stepped part in sequence in a backward direction, the second sealing ring is sleeved on the second stepped part, the second baffle ring and the second shoulder are clamped at two sides of the second sealing ring, the front end of the turbine shaft is provided with a second sealing sleeve, a first gap is formed between the outer periphery of the second comb tooth sealing structure and the inner periphery of the second sealing sleeve, the outer periphery of the second sealing ring is matched with the inner turnover of the second sealing sleeve in a dynamic sealing manner, the inner periphery of the air seal is provided with a fourth annular groove, a plurality of fifth through holes are formed in the air seal, and the fifth annular groove is communicated with the fourth annular groove through a plurality of fifth through holes;

a first bearing cavity is formed between the thrust bearing and the front annular baffle structure, and a second bearing cavity is formed between the second sealing sleeve, the second sealing ring and the front support bearing;

The first wheel disc and the second wheel disc are sleeved on the flange of the turbine shaft through a disc shaft connecting ring, the flange is located on the front side of the air seal, the turbine shaft is a hollow cylinder-type structural shaft, plugs are arranged at the front part and the rear part of the turbine shaft to form a closed shaft inner cavity, a plurality of fourth through holes are formed in the front end of the shaft inner cavity, the fourth through holes are communicated with a fourth annular groove, a plurality of third through holes are formed in the rear end of the shaft inner cavity, the third through holes are communicated with a second cavity, a front wall is arranged at the front end of the rectifier support, a third cavity is formed between the disc shaft connecting ring and the second sealing sleeve, a second gap is formed between the disc shaft connecting ring and the bearing shell, a wheel disc rear cavity is formed between the second wheel disc and the bearing shell, a third gap is formed between the second wheel disc and the front wall, one end of the first air supply pipe penetrates through the liner and is sequentially communicated with the second air supply pipe, the first cavity, the first through holes, the first annular grooves, the second through holes, the third through holes, the shaft inner cavity, the fourth through holes, the fifth through holes, the third annular grooves and the third gaps are formed between the third gaps and the third gaps.

Further, a labyrinth insert is installed between the first disk and the second disk.

Further, the bearing bush is sleeved on the turbine shaft, an annular positioning groove is formed in the periphery of the bearing bush, an inner ring of the rear support bearing, a thrust disc and the sleeve are sequentially abutted back and forth and embedded in the annular positioning groove, a shaft piece of the thrust bearing is sleeved on the sleeve, the thrust disc is abutted back and forth with the shaft piece of the thrust bearing, and a seat piece of the thrust bearing is connected with the bearing shell.

Further, the coupler is meshed with the turbine shaft through a spline structure and is axially fixed through a locating pin.

Compared with the prior art, the utility model has the beneficial effects that:

The utility model provides a sealing pressurizing air-entraining structure of a bearing cavity of a power turbine of a gas turbine, which sequentially provides sealing pressurizing air for a first bearing cavity and a second bearing cavity through the air-entraining structure after low-temperature compressed air is introduced from a certain stage of a gas compressor, and cools turbine shafts and rear edge parts of a first wheel disc and a second wheel disc of the power turbine along the edges, so that the sealing pressurizing effect is achieved, the cooling effect is simultaneously achieved, the consumption of the compressed air is saved, the structure is simplified, and the total working efficiency of the gas turbine is improved.

Drawings

FIG. 1 is a schematic illustration in semi-section of the present utility model;

FIG. 2 is an enlarged view at A of FIG. 1;

FIG. 3 is an enlarged view at B of FIG. 1;

FIG. 4 is a schematic view of a gas circuit component in semi-section;

FIG. 5 is a schematic illustration of a coupling in semi-section;

fig. 6 is a schematic diagram of a gas seal in semi-section.

In the drawing the view of the figure, A novel gas turbine engine comprises a first wheel disc, a second wheel disc, a front wall 4, a casing 5, a liner 6, a first gas supply pipe 7, a rectifier bracket 8, a second gas supply pipe 9, a rear annular baffle 10, a first chamber 12, a first through hole 13, a first comb tooth sealing structure 14, a coupling 15, a first annular groove 16, a second through hole 17, a second chamber 18, a third through hole 19, a first sealing ring 20, a first baffle ring 21, a first sealing sleeve structure 22, a turbine shaft 23, a first bearing cavity 24, a sleeve 25, a thrust bearing 26, a thrust bearing 27, a bearing liner. The seal assembly includes, by weight, a rear seat bearing, 29, a bearing housing, 30, an axle cavity, 31, a plug, 32, a front seat bearing, 33, a second bearing cavity, 34, a second retainer ring, 35, a second seal ring, 36, a fourth through hole, 37, a fourth annular groove, 38, a fifth through hole, 39, a fifth annular groove, 40, an air seal, 41, a second comb seal structure, 42, a second seal sleeve, 43, a third cavity, 44, a rear disk cavity, 45, a disk axle connecting ring, 46, an air passage member, 47, a front annular baffle structure, 48, a flange, 49, a first step, 50, a first shoulder, 51, a second shoulder, 52.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the present utility model is described below by means of specific embodiments shown in the accompanying drawings. It should be understood that the description is only illustrative and is not intended to limit the scope of the utility model. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present utility model.

The connection mentioned in the utility model is divided into fixed connection and detachable connection, wherein the fixed connection is a conventional fixed connection mode such as folding connection, rivet connection, bonding connection, welding connection and the like, the detachable connection comprises a conventional detachable mode such as bolt connection, buckle connection, pin connection, hinge connection and the like, and when a specific connection mode is not limited, at least one connection mode can be found in the conventional connection mode by default to realize the function, and the person skilled in the art can select the function according to the needs. For example: the fixed connection is welded connection, and the detachable connection is bolted connection.

The present utility model will be described in further detail below with reference to the accompanying drawings, the following examples being illustrative of the present utility model and the present utility model is not limited to the following examples.

Examples: 1-6, a gas turbine power turbine bearing cavity sealing pressurizing and air entraining structure comprises a turbine shaft 22, a bearing shell 29, a rectifier support 8 and a lining barrel 6 are sequentially sleeved on the turbine shaft 22 from inside to outside, the bearing shell 29 and the turbine shaft 22 are respectively connected in a rotating way through a front support bearing 32 and a rear support bearing 28, and a casing 5 is connected with the lining barrel 6;

The air path member 46 comprises a first sealing sleeve structure 21 and a front annular baffle structure 47 which are sleeved inside and outside, the rear annular baffle 10 is sleeved on the first sealing sleeve structure 21, the outer end of the front annular baffle structure 47 is connected with the rear end of the bearing shell 29, the outer periphery of the rear annular baffle 10 is in sealing connection with the outer periphery of the front annular baffle structure 47, a first cavity 11 is formed between the front annular baffle structure 47 and the rear annular baffle 10, and a plurality of first through holes 12 are formed in the first sealing sleeve structure 21 between the front annular baffle structure 47 and the rear annular baffle 10;

The coupler 14 is sleeved at the rear end of the turbine shaft 22, the coupler 14 is positioned at the rear side of the rear support bearing 28, the coupler 14 is meshed with the turbine shaft 22 through a spline structure and is axially fixed through a locating pin, a first stepped part 49, a first shaft shoulder 50, a first annular groove 15 and a first comb tooth sealing structure 13 are sequentially machined backwards in the outer Zhou Congqian of the coupler 14, a first sealing ring 19 is sleeved on the first stepped part 49, a first baffle ring 20 is sleeved on the coupler 14, the first baffle ring 20 and the first shaft shoulder 50 are respectively clamped at two sides of the first sealing ring 19, a first limiting end cover is connected with the coupler 14, the first limiting end cover presses the first baffle ring 20 and the first sealing ring 19 on the front end surface of the first shaft shoulder 50, the outer periphery of the first comb tooth sealing structure 13 is in close and rotating fit with the inner periphery of the first sealing sleeve structure 21, a second circulating sealing ring 19 is machined on the inner periphery of the coupler 14, a plurality of second annular grooves 16 are machined on the turbine shaft 22, a plurality of second annular grooves 16 are machined on the second annular grooves 16 and a plurality of second through holes 16 are formed on the coupler 14, and a plurality of through holes 16 are formed on the second annular grooves 16 and a plurality of through holes 16 are formed in the coupler;

The air seal 40 and the second baffle ring 34 are sleeved at the front part of the turbine shaft 22, the air seal 40, the second baffle ring 34 and the inner ring of the front support bearing 32 are propped against each other in sequence, the outer Zhou Congqian of the air seal 40 is provided with a second comb tooth sealing structure 41, a fifth annular groove 39, a second shoulder 51 and a second stepped part 52 in sequence, the second sealing ring 35 is sleeved on the second stepped part 52, the second baffle ring 34 and the second shoulder 51 are clamped at two sides of the second sealing ring 35, the front end of the turbine shaft 22 is provided with a second sealing sleeve 42, the second sealing sleeve 42 and a second limiting member are clamped at two sides of the outer ring of the front support bearing 32, the second limiting member is connected with the bearing shell 29 in a matched manner, the inner ring of the front support bearing 32 is propped against each other in a front-rear manner with a third limiting member, the third limiting member is connected with the turbine shaft 22 in a matched manner, a first gap is formed between the outer periphery of the second comb tooth sealing structure 41 and the inner periphery of the second sealing sleeve 42, the outer periphery of the second sealing ring 35 is in a movable sealing fit with the inner turnover of the second sealing sleeve 42, the inner periphery of the air seal 40 is provided with a plurality of annular grooves 37 and a plurality of through holes 37 are formed in the fourth annular grooves 37, and the fifth through holes 38 are communicated with each other;

A first bearing cavity 23 is formed between the thrust bearing 25 and the front annular baffle structure 47, and a second bearing cavity 33 is formed between the second seal cartridge 42, the second seal ring 35 and the front carrier bearing 32;

The first wheel disc 1 and the second wheel disc 3 are sleeved on a flange 48 of the turbine shaft 22 through a disc shaft connecting ring 45, the flange 48 is positioned at the front side of the air seal 40, the flange 48, a fourth limiting member and the air seal 40 are sequentially abutted back and forth, the turbine shaft 22 is a hollow cylindrical structural shaft, plugs 31 are arranged at the front part and the rear part of the turbine shaft 22 to form a closed shaft inner cavity 30, a plurality of fourth through holes 36 are formed at the front end of the shaft inner cavity 30, the plurality of fourth through holes 36 are communicated with a fourth annular groove 37, a plurality of third through holes 18 are formed at the rear end of the shaft inner cavity 30, the plurality of third through holes 18 are communicated with the second chamber 17, a front wall 4 is arranged at the front end of the rectifier support 8, a third chamber 43 is formed between the disc shaft connecting ring 45 and the second sealing sleeve 42, a second gap is formed between the disc shaft connecting ring 45 and the bearing shell 29, a disc rear chamber 44 is formed between the second wheel disc 3 and the bearing shell 29, a third gap is formed between the second wheel disc 3 and the front wall 4, one end of the first air supply pipe 7 penetrates through the lining 6, and is sequentially communicated with the second pipe 9, the first chamber 11, the third through holes 12, the fourth annular groove 37, the third through holes 16, the fifth through holes 17, the fifth through holes 37, the fifth through holes 43 and the third through holes 17, the third through holes 37, the fourth through holes 15, the fourth through holes 17, the fourth through holes and the fourth through holes 43.

A labyrinth insert 2 is mounted between the first wheel disc 1 and the second wheel disc 3.

The bearing bush 27 is sleeved on the turbine shaft 22, an annular positioning groove is formed in the periphery of the bearing bush 27, an inner ring of the rear support bearing 28, the thrust disc 26 and the sleeve 24 are sequentially abutted back and forth and are embedded into the annular positioning groove, a shaft piece of the thrust bearing 25 is sleeved on the sleeve 24, the thrust disc 26 is abutted back and forth with the shaft piece of the thrust bearing 25, and a seat piece of the thrust bearing 25 is connected with the bearing shell 29.

The first wheel disc 1, the labyrinth insert 2, the second wheel disc 3, the coupling 14, the first sealing ring 19, the first baffle ring 20, the turbine shaft 22, the sleeve 24, the thrust disc 26, the bearing bush 27, the plug 31, the second baffle ring 34, the second sealing ring 35, the gas seal 40 and the disc shaft connecting ring 45 are rotating parts, and other parts are static parts (except bearings).

The low-temperature compressed air introduced from the gas turbine compressor is introduced into the bearing portion of the power turbine through the first air supply pipe 7 and the second air supply pipe 9 in this order. The lubricating oil enters the first chamber 11 along the flow, then enters the first annular groove 15 through the first through holes 12 on the first sealing sleeve structure 21 for sealing pressurization, and the pressure in the first annular groove 15 is higher than the pressure in the first bearing cavity 23 so as to prevent lubricating oil leakage; the compressed air in the first annular groove 15 is divided into two parts, a small part of the compressed air enters the atmosphere through a gap between the first sealing sleeve structure 21 and the first comb tooth sealing structure 13, and the other most of the compressed air enters the second cavity 17 through the plurality of second through holes 16, enters the shaft cavity 30 of the turbine shaft 22 through the plurality of third through holes 18 on the turbine shaft 22, and cools the part along Cheng Touping shaft 22; the low-temperature compressed air flows from the shaft inner cavity 30 to the front part of the power turbine, enters a fourth annular groove 37 from a plurality of fourth through holes 36 on the turbine shaft 22, and then enters a fifth annular groove 39 through a plurality of fifth through holes 38 on the air seal 40 to carry out sealing pressurization, wherein the pressure in the fifth annular groove 39 is higher than the pressure in the second bearing cavity 33 so as to prevent lubricating oil leakage; the low-temperature compressed air continuously flows through the first gap formed between the second sealing sleeve 42 and the second comb tooth sealing structure 41, enters the third chamber 43, then enters the wheel disc rear chamber 44 through the second gap, cools the first wheel disc 1 and the second wheel disc 3 of the power turbine along the way and the corresponding parts, and finally flows into the main gas channel from the third gap between the second wheel disc 3 and the front wall 4.

The utility model provides a sealing pressurizing air-entraining structure of a bearing cavity of a power turbine of a gas turbine, which sequentially provides sealing pressurizing air for a first bearing cavity 23 and a second bearing cavity 33 through the air-entraining structure after low-temperature compressed air is introduced from a certain stage of a gas compressor, and cools turbine shaft 22 and rear edge parts of a first wheel disc 1 and a second wheel disc 3 of the power turbine along the edge, so that the sealing pressurizing effect is achieved, the cooling effect is simultaneously realized, the consumption of compressed air is saved, the structure is simplified, and the total working efficiency of the gas turbine is improved.

The above embodiments are only illustrative of the present utility model and do not limit the scope thereof, and those skilled in the art may also make modifications to parts thereof without departing from the spirit of the utility model.

Claims (4)

1. The utility model provides a gas turbine power turbine bearing chamber seals pressure boost bleed structure which characterized in that: the turbine shaft comprises a turbine shaft (22), a bearing shell (29), a rectifier bracket (8) and a lining cylinder (6) are sequentially sleeved on the turbine shaft (22) from inside to outside, and the bearing shell (29) and the turbine shaft (22) are respectively connected with each other in a rotating way through a front support bearing (32) and a rear support bearing (28);

The gas path member (46) comprises a first sealing sleeve structure (21) and a front annular baffle structure (47) which are sleeved inside and outside, the rear annular baffle (10) is sleeved on the first sealing sleeve structure (21), the outer end of the front annular baffle structure (47) is connected with the rear end of the bearing shell (29), the periphery of the rear annular baffle (10) is in sealing connection with the periphery of the front annular baffle structure (47), a first cavity (11) is formed between the front annular baffle structure (47) and the rear annular baffle (10), and a plurality of first through holes (12) are formed in the first sealing sleeve structure (21) between the front annular baffle structure (47) and the rear annular baffle (10);

The shaft coupling (14) is sleeved at the rear end of the turbine shaft (22), a first stepped part (49), a first shaft shoulder (50), a first annular groove (15) and a first comb tooth sealing structure (13) are sequentially machined backwards in the outer Zhou Congqian of the shaft coupling (14), a first sealing ring (19) is sleeved on the first stepped part (49), a first baffle ring (20) is sleeved on the shaft coupling (14), the first baffle ring (20) and the first shaft shoulder (50) are respectively clamped at two sides of the first sealing ring (19), the outer periphery of the first comb tooth sealing structure (13) and the inner periphery of the first sealing sleeve structure (21) are in close and rotating fit, the outer periphery of the first sealing ring (19) and the inner periphery of the first sealing sleeve structure (21) are in rotating and sealing fit, a second annular groove is machined in the inner periphery of the shaft coupling (14), a third annular groove is machined in the turbine shaft (22), the second annular groove and the third annular groove is combined with the third annular groove to form a second cavity (17), a plurality of through holes (16) are machined in the shaft coupling (14), and the second through holes (15) are communicated with the second cavity (17) through the second through holes (16);

The air seal (40) and the second baffle ring (34) are sleeved at the front part of the turbine shaft (22), the air seal (40), the second baffle ring (34) and the inner ring of the front support bearing (32) are propped against each other in sequence, the outer Zhou Congqian of the air seal (40) is provided with a second comb tooth sealing structure (41), a fifth annular groove (39), a second shoulder (51) and a second stepped part (52) in sequence, the second seal ring (35) is sleeved on the second stepped part (52), the second baffle ring (34) and the second shoulder (51) are clamped at two sides of the second seal ring (35), a first gap is formed between the outer periphery of the second comb tooth sealing structure (41) and the inner periphery of the second seal sleeve (42), the outer periphery of the second seal ring (35) is matched with the inner dynamic seal of the second turnover (42), the inner periphery of the air seal (40) is provided with a fourth annular groove (37), the air seal (40) is provided with a plurality of fifth through holes (38) and the fifth annular groove (37) are communicated with the fifth annular groove (38);

A first bearing cavity (23) is formed between the thrust bearing (25) and the front annular baffle structure (47), and a second bearing cavity (33) is formed between the second sealing sleeve (42), the second sealing ring (35) and the front support bearing (32);

The first wheel disc (1) and the second wheel disc (3) are sleeved on a flange (48) of the turbine shaft (22) through a disc shaft connecting ring (45), the flange (48) is positioned at the front side of the air seal (40), the turbine shaft (22) is a hollow cylinder structure shaft, plugs (31) are arranged at the front part and the rear part of the turbine shaft (22) to form a closed shaft inner cavity (30), a plurality of fourth through holes (36) are formed at the front end of the shaft inner cavity (30), the plurality of fourth through holes (36) are communicated with a fourth annular groove (37), a plurality of third through holes (18) are formed at the rear end of the shaft inner cavity (30), the plurality of third through holes (18) are communicated with a second chamber (17), a front wall (4) is arranged at the front end of the rectifier support (8), a third chamber (43) is formed between the disc shaft connecting ring (45) and the second seal sleeve (42), a second gap is formed between the disc shaft connecting ring (45) and the bearing shell (29), a rear chamber (44) is formed between the second wheel disc (3) and the bearing shell (29), a plurality of third through holes (18) are formed between the second wheel disc (3) and the first chamber (7), the first through holes (12) and the first through holes (12) are formed between the first through holes (7) and the first through holes (12) and the first through holes (7) in turn The novel wheel disc comprises a first annular groove (15), a plurality of second through holes (16), a second cavity (17), a plurality of third through holes (18), a shaft inner cavity (30), a plurality of fourth through holes (36), a fourth annular groove (37), a plurality of fifth through holes (38), a fifth annular groove (39), a first gap, a third cavity (43), a second gap, a wheel disc rear cavity (44) and a third gap.

2. The gas turbine power turbine bearing cavity seal pressurized bleed air structure of claim 1, wherein: a labyrinth insert (2) is arranged between the first wheel disc (1) and the second wheel disc (3).

3. The gas turbine power turbine bearing cavity seal pressurized bleed air structure of claim 1, wherein: the bearing bush (27) is sleeved on the turbine shaft (22), an annular positioning groove is formed in the periphery of the bearing bush (27), an inner ring of the rear support bearing (28), a thrust disc (26) and a sleeve (24) are sequentially abutted back and forth and embedded in the annular positioning groove, a shaft piece of the thrust bearing (25) is sleeved on the sleeve (24), the thrust disc (26) is abutted back and forth with the shaft piece of the thrust bearing (25), and a seat piece of the thrust bearing (25) is connected with the bearing shell (29).

4. A gas turbine power turbine bearing cavity seal pressurized bleed air structure according to any of claims 1-3, characterized in that: the coupling (14) is engaged with the turbine shaft (22) by a spline arrangement and is axially secured by a dowel pin.