JP2002115699A - Variable stationary blade assembly body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable stationary blade assembly body avoiding a problem of a positioning shift without depending on paying extreme attention during assembly. SOLUTION: A variable stationary blade assembly body 10 is provided with at least one stationary blade 14 having a trunnion 18 to pivotally support the stationary blade 14 on a casing 12 formed thereon. The stationary blade 14 includes a head 28 formed at an end part of the trunnion 18 and a threaded stem 30 formed at an end part of the head 28. A level arm 32 is provided with a boss 34 formed on one end thereof and an attachment hole 36 formed on the boss 34. The lever arm 32 is connected to the stationary blade 14 by arranging the head 28 in the attachment hole 36. The boss 34 of the lever arm 32 is higher than the threaded stem 30 to prevent the threaded stem 30 from being threadedly engaged with a retention nut before the head 28 is arranged in the attachment hole 36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to gas turbine engines and, more particularly, to variable vanes used in such engines.

[0002]

2. Description of the Related Art A gas turbine engine includes a compressor for supplying pressurized air to a combustor, in which air is mixed with fuel and ignited to generate hot combustion gas.
The hot combustion gases flow downstream to one or more turbines where turbines extract energy from the gas to power compressors and power aircraft in flight. Do a great job. A typical gas turbine engine compressor has a circumferentially spaced compressor vane located between several rows of circumferentially spaced compressor blades. With several columns. Each corresponding row of vanes and buckets constitutes a stage of the compressor. In operation, fresh air is continuously compressed as it flows through each successive compressor stage, creating compressed air that is supplied to the combustor.

In order to improve the overall operation of the compressor,
Some compressor vanes are rotatably supported such that each vane rotates about its longitudinal or radial axis and can adjust the angular orientation of the vanes relative to the airflow flowing over them. You. Such a variable vane includes an integral outer trunnion disposed in a complementary support boss of the stator casing such that the vane can rotate relative to the casing. The lever arm is fixedly connected at one end thereof to a spindle which extends coaxially outwardly from the outer end of the wing trunnion. The other end of the lever arm is operatively coupled to an actuation ring that controls the angle of the wing. All wing lever arms in a single row are coupled to a common actuation ring to ensure that all variable wings are at the same angular orientation relative to the compressor stage airflow. You.

[0004] Typically, the spindle includes a D-shaped seat at the top of the trunnion and a threaded stem extending outwardly from the seat. The proximal end of each lever arm has a corresponding D-shaped mounting hole that mates with the seat and a nut is threaded onto the stem to hold the lever arm on the spindle.
The corresponding D-shape is provided such that the lever arm is correctly aligned with each wing trunnion (during initial compressor assembly or field maintenance). The mounting holes are
Generally, the width is slightly smaller than the width of the trunnion seat, and by tightening a nut on the stem, the lever arm is pushed into the trunnion seat to make a tight fit. The mounting holes are
Slightly larger than the diameter of the stem, the lever arm can pass through the stem.

[0005] The corresponding D-shape of the trunnion seat and lever arm mounting holes is intended to eliminate misalignment between them, but nevertheless obtains an interference fit between them. The assembly process can result in misalignment when an interference fit is configured.
The mounting holes are larger than the threaded stems, and misalignment with respect to the trunnion seat if proper care is not taken to ensure accurate alignment when the lever arm is placed on the spindle. May occur.
A subsequent tightening of the retaining nut without confirming that the lever arm is in the correct direction can result in an angular misalignment between the lever arm and each wing. The force generated by applying torque to the nut has the potential to cause plastic deformation of the metal matrix of both the trunnion seat and the lever arm. Since this joint is covered by the retaining nut, such misalignment is not noticed during assembly. Misalignment of the lever arm can result in reduced engine efficiency, increased wear on engine metal products, and even engine failure.

[0006]

Accordingly, it would be desirable to provide a variable vane assembly that avoids the aforementioned misalignment problems without relying on extreme care during assembly.

[0007]

SUMMARY OF THE INVENTION The foregoing needs are met by the present invention which provides a variable vane assembly having at least one vane formed with a trunnion for pivotally supporting the vane to a casing. The vane further includes a head formed at the end of the trunnion and a threaded stem formed at the end of the head. The lever arm has a boss formed at one end thereof and a mounting hole formed in the boss. The lever arm is connected to the vane by placing the head in the mounting hole. The lever arm boss has a height greater than the threaded stem to prevent the retaining nut from being screwed into the threaded stem before the head is placed in the mounting hole.

[0008] The present invention and its advantages over the prior art will become apparent from the following detailed description and appended claims, taken in conjunction with the accompanying drawings.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS The subject matter which is considered as the invention is particularly pointed out and claimed at the outset of this specification. However, the present invention may be best understood by reference to the following description taken in conjunction with the accompanying drawings.

In the drawings, the same reference numerals denote the same components throughout the various figures, while FIGS.
Shows a variable vane assembly 10 secured to an annular compressor casing 12 of an exemplary gas turbine engine compressor.
The variable vane assembly 10 includes a plurality of circumferentially-spaced variable vanes 14 (only one is shown in the figure). Each wing 14 includes a conventional airfoil 16 having a leading edge, a downstream trailing edge, and a pressure side and a suction side extending therebetween.

Each wing 14 further includes an integral outer trunnion 18 extending radially outward from the outer end of the airfoil 16 to pivot the wing 14 to a corresponding support boss 20 formed in the compressor casing 12. To support. A trunnion bush 22 is disposed between the outer trunnion 18 and the support boss 20 to reduce friction and wear therebetween. FIG.
According to the exemplary embodiment shown in FIG. 1, each wing 14 also includes an integral inner trunnion 24 that extends radially inward from the inner end of the airfoil 16. Inner trunnion 24
Is supported in a seal ring 26 located radially inward of the casing 12, although other arrangements can be used.

The mounting spindle is the outer trunnion 18
At the radially outer end of the The mounting spindle is a quadrilateral or generally D-shaped head or seat 2 integrally formed at the outer end of the trunnion 18.
8 inclusive. D-shaped head 28 extends radially outward and coaxially from outer trunnion 18. As can be best seen in FIG. 2, the D-shaped head 28 includes a base plane, a pair of opposing parallel seating planes, and an arched side surface opposite the base plane and extending between the seating planes. . These surfaces collectively form a D-shaped configuration of the head 28 as a whole. The threaded stem 30 is D
It is formed integrally with the radially outer end of the letter-shaped head 28. The threaded stem 30 extends radially outward from the D-shaped head 28 and extends coaxially with both the outer trunnion 18 and the D-shaped head 28.

The lever arm 32 has a boss 34 formed at one end thereof. Mounting hole 36 formed in boss 34
Can be positioned on the mounting stem 30 to seat on the D-shaped head 28. The mounting hole 36 is a generally D-shaped hole that is complementary to the D-shaped head 28.
Specifically, the mounting hole 36 has a base side plane, a pair of opposing parallel hole planes, and an arched side surface extending between the hole planes. The hole plane faces vertically with respect to the lever arm 32. D-shaped head 28 and mounting hole 3
6 are dimensioned relative to each other such that when the D-shaped head 28 is positioned in the mounting hole 36, the seating plane of the D-shaped head 28 mates with the hole plane of the mounting hole 36 with an interference fit. I have. Therefore, the outer trunnion 18 is fixed to the lever arm 32 so as to rotate with the lever arm 32, and the rotational movement of the lever arm 32 is transmitted to the wing 14. A washer 38 is installed on the threaded stem 30,
The holding nut 40 is screwed into the stem 30 to move the lever arm 3
2 is fixed at a predetermined position on the D-shaped head 28.

The operating pin 42 is connected to the boss 34 of the lever arm 32.
And is received in a complementary hole in annular actuation ring 44 (FIG. 1) to control the position of lever arm 32. The lever arm of each vane 14 has an operating ring 44
As a result, the direction in which the wing 14 faces can be adjusted simultaneously.

Referring to FIG. 2, the lever arm boss 34
It found to have a thickness or height h ₁ significantly larger than the thickness of the remainder of the lever arm 32. D-shaped head 2
8 has a height h ₂ defined by the distance that the D-shaped head 28 extends beyond the outer trunnion 18 and the threaded stem 30 is defined by the distance that the stem 30 extends beyond the D-shaped head 28. It has a height h _3. Lever arm boss height h ₁ is the stem greater than the height h _3. This prevents the retaining nut from starting to advance on the threads of the stem before the lever arm 32 is securely engaged with the D-shaped head 28. In other words, since the larger lever arm boss height h ₁ is the stem height h ₃ (with a proper margin to stacking tolerance), the lever arm boss 34 on the mounting hole 36 is D-shaped head 28 If the seating plane is not at least partially seated (i.e., the seating plane of the D-shaped head 28 meshes with the hole plane of the mounting hole 36), the threaded stem 30 will be completely obscured. Mounting hole 3
If 6 is not at least partially seated on the D-shaped head 28, it is not possible to start screwing the retaining nut 40 onto the threaded stem 30. This prevents the retaining nut 40 from being tightened, and at the same time prevents the lever arm from being misaligned with respect to the D-shaped head 28 and the components being forcibly pressed together in the misaligned state. .

In addition, the lever arm boss height h ₁ is equal to or slightly greater than the D-shaped head height h ₂ , so that when properly assembled, the lever arm 32 will have a trunnion seat or shoulder 19. (Trunnion 18 and D-shaped head 28
And the holding nut 40 is firmly fixed. As a result, D-shaped head height h ₂ is also greater than the stem height h _3, the stem height h ₃ is greater than the lever arm boss accept height h _1.

The foregoing has described a variable vane assembly that prevents the retaining nut from being screwed into the threaded stem of the vane if the lever arm is not properly aligned with the vane. Having described certain embodiments of the invention,
It will be apparent to those skilled in the art that various changes can be made thereto without departing from the spirit and scope of the invention as set forth in the appended claims.

[Brief description of the drawings]

FIG. 1 is a radial cross-sectional view of a variable stator vane assembly.

FIG. 2 is an exploded perspective view of a part of the variable stator vane assembly of FIG. 1;

[Explanation of symbols]

10 variable stator vane assembly 12 casing 14 stator blades 16 airfoil 18 trunnion 28 head 30 a threaded stem 32 lever arm 34 a boss 36 mounting holes 38 washer 40 retaining nut h ₁ lever arm boss height h ₂ head height h ₃ Stem height

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenneth Edward Staitzer United States, Ohio, Mason, Buckeye Court, No. 1062 (72) Inventor Mark Willard Marsco United States of America, Ohio, Springboro, Ohio Pine Ridge Court, 20th F term (reference) 3H034 AA02 AA16 BB03 BB08 BB19 CC03 DD07 DD26 DD30 EE05

Claims (9)

[Claims] An airfoil (16) formed at one end with a trunnion (18) for pivotally supporting a stator vane (14) to a casing (12), and formed at an end of the trunnion (18). Head (2
8) and a threaded stem formed at an end of the head (28), wherein the head (28) has a height greater than the threaded stem (30). Stationary wing (14). 2. The head (28) is formed integrally with the trunnion (18) and includes a threaded stem (3).
The vane (14) according to claim 1, wherein 0) is formed integrally with the head (28). 3. The vane according to claim 1, wherein the head has at least one seating plane. 4. The head (28) has a generally D-shaped configuration and includes a base-side plane, a pair of opposing parallel seating planes, and a space between the seating planes opposite the base-side plane. The vane (14) according to claim 1, characterized in that the vane (14) has an arcuate side surface extending in the direction of the arrow. 5. At least one vane (14) formed with a trunnion (18) for pivotally supporting the vane (14) to the casing (12), and formed at an end of the trunnion (18). Head (2
8), a threaded stem (30) formed at the end of the head (28), a boss (34) formed at one end thereof, and the boss (34)
Lever arm (3) having a mounting hole (36) formed in
2) wherein the head (28) is disposed in the mounting hole (36) and the boss (34) has a height greater than the threaded stem (30). Wing assembly (10). 6. The head (28) is integrally formed with the trunnion (18) and includes the threaded stem (3).
A variable vane assembly (10) according to claim 5, wherein 0) is formed integrally with the head (28). 7. The variable of claim 5, wherein the head (28) has at least one seating plane and the mounting hole (36) has at least one hole plane that mates with the seating plane. Stator blade assembly (10). 8. The head (28) has a generally D-shaped configuration and includes a base side plane, a pair of opposing parallel seating planes, and an arched side surface extending between the seating planes. Said mounting hole (36) has a generally D-shaped configuration, a base side plane, a pair of opposed parallel hole planes,
A variable vane assembly (10) according to claim 5, comprising an arcuate side surface extending between the bore plane and the bore plane, the bore plane engaging the seating plane. 9. The system according to claim 5, further comprising a retaining nut (40) screwed into said threaded stem (30) to secure said lever arm (32) to said head (28). Variable vane assembly (10).