Turbine shaft journal for an aircraft turbomachine

Abstract

The invention relates to a journal (109) for an aircraft turbomachine shaft, the journal extending about an axis (X) and comprising - an upstream end intended to be fastened to a turbomachine shaft, - a downstream end intended to be fastened to a turbomachine rotor element, - a flared connecting wall (112), and wherein the connecting wall (112) comprises a plurality of air passage orifices (113), and wherein, for each orifice, a maximum extension dimension (120) between two circumferential ends of the orifice (113) is greater than a maximum extension dimension between two axial ends of the orifice (113), each of the two circumferential ends (116, 117) being connected to the two axial ends (114, 115) by a respective rounded junction portion (124, 125, 126, 127).

Description

Description Title of the invention: Turbine shaft trunnion for aircraft turbomachinery Technical Field

[0001] This presentation concerns the field of turbomachinery such as turboprops or turbojets.

[0002] More particularly, the invention relates to the field of turbines for aircraft turbomachinery, and more specifically to turbine shafts for aircraft turbomachinery. Previous technique

[0003] In a turbomachine, a turbine shaft transmits power from the turbine to a compressor shaft. To achieve this, the turbine shaft has a trunnion at one end. This trunnion connects the turbine shaft to the compressor shaft and has one end fixed to the compressor shaft.

[0004] In some turbine shafts, for example a low-pressure turbine shaft, this journal has circular through-holes that allow a cooling fluid to pass from the high-pressure turbine towards the flow path downstream of the compressor shaft. In other configurations, these through-holes can also allow for containment or other pressurization within the turbomachine.

[0005] To control the fluid flow through the journal, the cross-section of the passage holes must be precisely calibrated. However, the journal forms a structural connection between the turbine shaft and the compressor shaft. Therefore, the journal is subjected to significant stresses during operation. The presence of these passage holes weakens the journal's structure and generates stress concentrations within the journal between circumferentially adjacent air passage holes. This structural weakening of the journal and the stress concentration can lead to turbomachine damage.

[0006] Furthermore, the amount of material at a small diameter on a trunnion is limited, so there is an incompatibility between the required cross-sectional area of Ventilation through the passage holes and the need for mechanical strength of the trunnion. The passage holes then reduce the trunnion's resistance to loads and generate an increased concentration of stresses, weakening the trunnion's structure.

[0007] There is therefore a real need for a trunnion with passage orifices allowing a controlled flow of cooling fluid while having a satisfactory weight and resistance to mechanical stresses. Description of the invention

[0008] One idea underlying the invention is to provide a turbine shaft that allows for ventilation while maintaining satisfactory mechanical resistance to stress. More specifically, one idea underlying the invention is to propose a cross-section for the ventilation ports that ensures adequate ventilation without compromising the mechanical strength of the journal. In particular, one idea underlying the invention is to propose a cross-section for the ventilation ports that also lightens the journal.

[0009] To this end, the invention provides a trunnion for an aircraft turbomachine shaft, said trunnion extending around an axis (X) and comprising - an upstream end intended to be fixed to a turbomachine shaft, - a downstream end intended to be attached to a turbomachine rotor element, - a flared connecting wall, the connecting wall linking the upstream end of the trunnion and the downstream end of the trunnion, and in which the connecting wall has a plurality of air passage orifices distributed circumferentially around the axis (X), each orifice being delimited by two opposite circumferential ends and by two opposite axial ends, the circumferential ends of each orifice defining between them a first extension dimension of said orifice and the axial ends of each orifice defining between them a second extension dimension of said orifice, and in which, for each orifice, on the one hand the first extension dimension of the orifice has a maximum dimension which is greater than a maximum dimension of the second extension dimension of the orifice, and on the other hand, each of the two circumferential ends is connected to the two axial ends by a respective rounded junction portion.

[0010] Thanks to these characteristics, the circumferential space occupied by the passage holes allows the journal to maintain good mechanical strength despite their presence, while also resulting in a lighter journal with a satisfactory airflow cross-section. Indeed, these characteristics make it possible to have a circumferentially wider than axially long airflow cross-section for the holes, thus increasing the circumferential dimensions while minimizing the radial dimensions. This allows for sufficient material to ensure the journal's mechanical strength by limiting the size of the holes along the second dimension of extension, typically axially, and therefore particularly in areas where the journal has a small diameter and little material.This is also possible while maintaining a satisfactory passage cross-section for airflow and reducing the weight of the trunnion, typically by increasing the size of the orifices according to the first extension dimension.

[0011] According to different embodiments, the trunnion according to the invention may comprise one or more of the characteristics below, alone or in combination.

[0012] In order to allow the passage of fluid, for example a cooling fluid, the passage orifices are through-holes.

[0013] In one embodiment, the air passage openings have a shape distinct from a circle; in other words, these openings are non-circular. Preferably, the air passage openings have an identical cross-sectional area.

[0014] In one embodiment, the connecting wall has a downstream diameter and an upstream diameter. For example, the upstream diameter of the connecting wall is at a junction with the upstream end of the trunnion. Similarly, the downstream diameter is, for example, at a junction with the downstream end of the trunnion. Preferably, the downstream diameter is distinct from the upstream diameter.

[0015] According to one embodiment, the connecting wall is frustoconical.

[0016] According to one embodiment, the downstream diameter is greater than the upstream diameter.

[0017] According to one embodiment, the upstream diameter is greater than the downstream diameter.

[0018] According to one embodiment, at least one of the two, and preferably both, circumferential ends of each orifice is straight.

[0019] According to one embodiment, the orifices are distributed circumferentially in a regular manner around the axis (X). Thus, a circumferential distance separating two adjacent orifices is identical and / or follows a regular pattern over the entire circumference of the wall.

[0020] In one embodiment, the first extension dimension of each orifice is less than or equal to a circumferential distance separating said orifice from another circumferentially adjacent orifice. In other words, the wall material retained between two adjacent orifices is greater than the first extension dimension, for example, the circumferential width.

[0021] According to one embodiment, the first extension dimension of each orifice is decreasing from a respective downstream end of the two circumferential ends of said orifice to a respective upstream end of the two circumferential ends of said orifice.

[0022] According to one embodiment, a circumferential width between the two circumferential ends of each air passage orifice is proportional to a conicity of the connecting wall.

[0023] The circumferential width is defined here by a circumferential direction, that is, around the (X) axis. In other words, the circumferential width of an orifice is determined according to the axial position at which it is measured and can therefore take different values ​​depending on said axial position at which it is measured.

[0024] Thanks to these characteristics, the circumferential space between the circumferential ends of the orifices is related to the amount of material present in the connecting wall at said circumferential ends, such that the wall retains a sufficient amount of material to ensure good mechanical resistance of the trunnion despite the presence of the through-holes. Furthermore, as explained above, by appropriately choosing the circumferential width of the orifices, it is possible to limit the radial bulk of said orifices, in particular at low wall diameter, while maintaining a satisfactory passage section and thus lightening the trunnion.

[0025] For example, a wall exhibiting a strong taper with a small upstream diameter, and therefore little material available near the upstream end, presents satisfactory mechanical resistance despite the presence of orifices because the circumferential width of these orifices decreases from downstream to upstream proportionally to the reduction in diameter of the wall, and therefore of available material of the wall.

[0026] According to one embodiment, each orifice is symmetrical with respect to an axial plane of the trunnion.

[0027] According to one embodiment, at least one of the two axial ends, and preferably both axial ends, of each orifice extends in a plane perpendicular to the axis (X).

[0028] According to one embodiment, each orifice has two circumferentially opposed upstream junction portions and two circumferentially opposed downstream junction portions, each of said junction portions connecting one of the two circumferential ends to one of the two axial ends, said junction portions extending along portions of arcs of circles.

[0029] In one embodiment, the upstream junction portions of each orifice have the same radius of curvature. In another embodiment, the downstream junction portions of each orifice have the same radius of curvature.

[0030] According to one embodiment, the circumferential width of each orifice is maximum at a junction between the two circumferential ends and the downstream junction portions.

[0031] In one embodiment, a first downstream junction portion has a first downstream center of curvature and a first downstream radius of curvature. In another embodiment, a second downstream junction portion has a second downstream center of curvature and a second downstream radius of curvature. In another embodiment, the first downstream center of curvature and the second center downstream curvature centers have the same axial position. According to one embodiment, a circumferential distance separating the first downstream center of curvature and the second downstream center of curvature is greater than or equal to, and preferably equal to, twice the first downstream radius of curvature and / or the second downstream radius of curvature.

[0032] According to one embodiment, a circumferential width of each orifice is minimal at a junction between the two circumferential ends and the upstream junction portions.

[0033] In one embodiment, a first upstream junction portion has a first upstream center of curvature and a first upstream radius of curvature. In another embodiment, a second upstream junction portion has a second upstream center of curvature and a second upstream radius of curvature. In another embodiment, the first upstream center of curvature and the second upstream center of curvature have the same axial position. In another embodiment, a circumferential distance separating the first upstream center of curvature and the second upstream center of curvature is greater than or equal to, and preferably equal to, twice the first upstream radius of curvature and / or the second upstream radius of curvature.

[0034] Circular arc junction portions such as those described above allow for a reduction in pressure losses in the flow passing through the air passage orifices.

[0035] In one embodiment, at least one of the following, on the one hand, the first and second downstream circles and, on the other hand, the first and second upstream circles, forming the orifice, are tangent. The first or second downstream circle is understood to be a circle whose center is respectively the first downstream circle of curvature or the second downstream center of curvature and whose radius is the corresponding radius of curvature. Similarly, the first or second upstream circle is understood to be a circle whose center is respectively the first upstream center of curvature or the second upstream center of curvature and whose radius is the corresponding radius of curvature.

[0036] According to one embodiment, a circumferential distance separating the upstream centers of curvature is less than a circumferential distance separating the downstream centers of curvature.

[0037] According to one embodiment, at least one of the downstream radii of curvature is, and preferably both are, greater than the upstream radii of curvature.

[0038] According to one embodiment, at least one of the upstream end of the trunnion and the downstream end of the trunnion extends radially in projection so as to form a trunnion fixing flange.

[0039] The invention also provides an aircraft turbomachine comprising a casing extending around an axis (X), a turbomachine shaft, a turbine rotor shaft and a trunnion as above, the turbomachine shaft, the turbine rotor shaft and the trunnion being rotatably mounted about the axis (X) and the trunnion being fixed, preferably by bolting, on one side to the upstream end of the trunnion to the turbomachine shaft, and on the other side, to the downstream end of the trunnion to the turbine rotor shaft.

[0040] The aforementioned features and advantages, as well as others, will become apparent upon reading the following detailed description of examples of embodiments of a turbine shaft journal according to the invention. This detailed description refers to the accompanying drawings. Brief description of the drawings

[0041] The attached drawings are schematic and are primarily intended to illustrate the principles of the presentation. [Fig. 1] Figure 1 is a schematic cross-sectional view of an aircraft turbomachine; [Fig. 2] Figure 2 is a partial cross-sectional view of an aircraft turbomachine turbine shaft comprising a trunnion having circular air passage orifices; [Fig. 3] Figure 3 is a schematic perspective view of a trunnion analogous to the trunnion in Figure 2; [Fig. 4] Figure 4 is a partial schematic perspective view of a trunnion according to the invention; [Fig. 5] Figure 5 is a schematic representation of a passage orifice of the trunnion in figure 4 projected onto a plane parallel to the longitudinal axis of the trunnion; [Fig. 6] Figure 6 is a schematic representation of a trunnion passage orifice according to a first variant of the embodiment; [Fig. 7] Figure 7 is a schematic representation of a trunnion passage hole according to a second embodiment variant; Description of the implementation methods

[0042] In this discussion, the terms "axial," "circumferential," "internal," "external," and their derivatives are defined with respect to the main axis (X) of the journal. This main axis of the journal is coaxial with the axis of the turbine shaft on which the journal is mounted, and therefore with the axis of the turbomachine. The "axial plane" is understood to be a plane passing through the main axis of the turbomachine, and the "radial plane" is a plane perpendicular to this main axis. Furthermore, the terms "upstream" and "downstream" are defined with respect to the airflow within the turbomachine.

[0043] Figure 1 represents, in cross-section along a vertical plane passing through the main axis X, a turbofan engine 1. This turbofan engine 1 comprises, from upstream to downstream along the airflow circulation G, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6, and a low-pressure turbine 7.

[0044] In order to transmit power between the different stages of the turbomachine 1, transmission shafts are used. Thus, in the example illustrated in Figure 2, a low-pressure turbine shaft 8 transmits power from the low-pressure turbine 7 to the low-pressure compressor shaft (not shown) 3.

[0045] Figure 3 illustrates a trunnion 9 analogous to the trunnion arranged at the end of the turbine shaft 8 in Figure 2. Such a trunnion 9 has a first end 10 fixed to the shaft of the shaft 8 and a second end 11 fixed to a portion (not shown) of the rotor of the low-pressure compressor. This fixing can be achieved by any means. For example, in the embodiment illustrated in Figure 2, the second end 11 extends radially in projection so as to form a fixing flange for the trunnion 9. This fixing flange It includes axially extending through-holes for housing bolts for bolting the mounting flange, and thus the trunnion 9, to the portion of the low-pressure compressor rotor. Similarly, and not shown in Figure 2, the first end 10 could extend radially to form a mounting flange with axially extending through-holes for bolting the trunnion 9 to the shaft 8. This trunnion 9 has a conical wall 12, also called a connecting wall or connecting cone, linking the first end 10 and the second end 11. The wall 12 has openings 13 allowing the passage of a cooling fluid from the high-pressure turbine 6 towards a channel downstream of the low-pressure compressor 3.

[0046] In Figures 2 and 3, the orifices 13 are circular. The need for the passage of the cooling fluid necessitates a calibrated cross-section for the orifices 13. Furthermore, these orifices 13 help to limit the weight of the journal 9. However, the wall 12, which connects the shaft 8 to the turbine discs of the low-pressure compressor 3, is subjected to significant stresses during nominal operation or in the event of a failure. The presence of the orifices 13 weakens the wall 12 and creates a zone of concentrated mechanical stress on this wall 12.

[0047] Furthermore, the amount of material in the wall 12 near the first end 10, i.e. where said wall 12 has a small diameter, is more impacted by the cross-section of the orifices 13. There is therefore an incompatibility between the need for ventilation cross-sections via the calibrated orifices 13 and the need for mechanical strength of the wall 12.

[0048] Figure 4 illustrates a trunnion according to an embodiment of the invention. Figure 5 illustrates an opening of the trunnion of Figure 4 projected onto a plane parallel to the longitudinal axis of the trunnion. Where reference is made to an element projecting in a given direction in the following description, the projection in question is a projection onto a plane parallel to the principal axis X of the trunnion as illustrated in Figure 5. Furthermore, in these Figures 4 and 5, the elements identical to or performing the same function as The elements illustrated and described opposite figures 2 and 3 bear the same reference number incremented by 100.

[0049] As illustrated in Figures 4 and 5, the orifices 113 in the wall 112 of a trunnion 109 according to this embodiment of the invention have a substantially trapezoidal shape. Typically, the orifices 113 in the wall 112 have a shape that fits within a trapezoid and has rounded corners. Thus, the orifice 113 has two opposing circumferential ends and two opposing axial ends. More specifically, the two axial ends form a downstream end, also referred to below as the downstream edge 114, and an upstream end, also referred to below as the upstream edge 115, of the orifice 113. Similarly, the two circumferential ends form a first circumferential end, also referred to below as the first lateral edge 116, and a second circumferential end, also referred to below as the second lateral edge 117, of the orifice 113.

[0050] The downstream edge 114 develops in the circumferential direction, typically in a radial plane. Thus, this downstream edge 114 extends in projection perpendicular to the X-axis. Similarly, the upstream edge 115 develops in the circumferential direction, typically in a radial plane and therefore in projection perpendicular to the X-axis. The downstream edge 114 and the upstream edge 115 develop circumferentially in parallel radial planes and are therefore, in projection, parallel.

[0051] The first lateral edge 116 develops, in projection, along a first axis 118. The second lateral edge 117 develops, in projection, along a second axis 119. The first axis 118 and the second axis 119 are secant and intersect upstream of the trunnion 109. In other words, a circumferential width 120 of the orifice 113 taken, in projection, perpendicular to the axis X is decreasing from a downstream end 121 of the lateral edges 116, 117 towards an upstream end 122 of said lateral edges 116, 117.

[0052] Thus, the shape of the orifices 113 presents a reduced circumferential footprint where the wall 112 has the smallest diameter and therefore the least material. Conversely, the footprint of these orifices 113 is significant where the wall 112 has the largest diameter and therefore the most material. This adjustment of the circumferential width of the orifice 113, based on the amount of material available on the wall 112, limits the cross-sectional area along the X-axis of the orifices 113 for the through flow, thus limiting the radial bulk of the orifices 113 while maximizing the amount of working material in the small-diameter wall 12. Therefore, once the satisfactory cross-sectional area of ​​the orifices 113 is determined, it is possible to limit their radial bulk, particularly in the upstream part of the wall 112, which has the smallest diameter, by adjusting their circumferential size. This adjustment of the circumferential size of the orifices 113 maximizes the circumferential cross-sectional area and thus reduces the weight of the trunnion 109.

[0053] As illustrated in Figure 4, the orifices 113 are regularly distributed along the circumference of the wall 112. Furthermore, a circumferential distance 123 separating the lateral edges 116, 117 opposite two adjacent orifices 113 is greater than or equal to the circumferential width 120 of said adjacent orifices 113. This arrangement ensures that there is sufficient material in the wall 112 between two adjacent orifices 113 to guarantee the mechanical stability of the trunnion 109.

[0054] The orifice 13 illustrated in figures 4 and 5 is symmetrical in an axial plane. In addition, this orifice 113 has a first downstream junction portion 124 connecting the first lateral edge 116 and the downstream edge 114, a second downstream junction portion 125 connecting the second lateral edge 117 and the downstream edge 114, a first upstream junction portion 126 connecting the first lateral edge 116 and the upstream edge 115 and a second upstream junction portion 127 connecting the second lateral edge 117 and the upstream edge 115.

[0055] The first downstream junction portion 124 is an arc of a circle with a first downstream center of curvature 128 and a first downstream radius of curvature 129. Similarly, the second downstream junction portion 125 is an arc of a circle with a second downstream center of curvature 130 and a second downstream radius of curvature 131. The first downstream center of curvature 128 and the second downstream center of curvature 130 are arranged in the same axial position and are circumferentially separated by a first distance 132.

[0056] Similarly, the first upstream junction portion 126 and the second upstream junction portion 127 are in arc of a circle with a first upstream center of curvature 133, respectively a second upstream center of curvature 135, and a first upstream radius of curvature 134, respectively a second upstream radius of curvature 136. The first upstream center of curvature 133 and the second upstream center of curvature 135 are arranged in the same axial position and are circumferentially spaced by a second distance 137.

[0057] The second distance 137 is less than the first distance 136. In addition, the first downstream radius of curvature 129 and the second downstream radius of curvature 131 are larger than the first upstream radius of curvature 134 and the second upstream radius of curvature 136, respectively. Such an arrangement of the centers of curvature 128, 130, 133 and 135 and the radii of curvature 129, 131, 134 and 136, as well as their respective distances, allows the orifice 113 to have a substantially trapezoidal shape, as illustrated in Figure 5.

[0058] In this embodiment, the first axis 118 is tangent to the first downstream portion 124 and to the first upstream portion 126. Similarly, the second axis 119 is tangent to the second downstream portion 125 and to the second upstream portion 127.

[0059] However, while the embodiment illustrated in Figures 4 and 5 allows the circumferential width 120 of the orifices 113 to be adjusted to maintain sufficient material between two adjacent orifices 113, the shape of the orifice 113 can change depending on the inclination of the cone formed by the wall 112. Indeed, the greater the inclination of the wall 112 with respect to the X-axis, the greater the difference in diameter between the diameter of the wall 112 at the upstream end and the diameter of the wall 112 at the downstream end. Consequently, the greater the taper of the wall 112, the less material is available to form the orifices 113 at the upstream end compared to the amount of material available to form the orifices 113 at the downstream end.

[0060] Thus, the shape of the orifices 113 can vary depending on the taper of the wall 112. More specifically, the circumferential width 120 of the orifices 113 is preferably proportional to the taper of the wall 112. This The proportionality between the conicity of the wall 112 and the circumferential width of the orifice 113 ensures a circumferential width adapted according to the quantity of material available in the wall 112.

[0061] In the embodiment illustrated in Figure 6, the orifice 113 is such that the upstream edge 115 is non-existent, the first upstream junction portion 126 being directly contiguous with the second upstream junction portion 127. In other words, the first upstream center of curvature 133 is identical to the second upstream center of curvature 135 and the first upstream radius of curvature 134 is identical to the second upstream radius of curvature 136. This embodiment corresponds to a wall 112 with a significant taper, so that the amount of material available to form the upstream edge 115 is limited.

[0062] Conversely, the orifice 113 illustrated in Figure 7 has parallel lateral edges 116 and 117 such that the upstream edge 115 and the downstream edge 114 have the same circumferential width. This embodiment corresponds to a cylindrical wall 112, in which the amount of material available to form the orifices 113 is the same all along the longitudinal axis X, so that the circumferential width 120 is constant between the lateral edges 116 and 117.

[0063] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Demands

1. Trunnion (109) for an aircraft turbomachine shaft, said trunnion extending about an axis (X) and comprising - an upstream end intended to be fixed to a turbomachine shaft, - a downstream end intended to be attached to a turbomachine rotor element, - a flared connecting wall (112), the connecting wall (112) linking the upstream end of the trunnion and the downstream end of the trunnion, and wherein the connecting wall (112) has a plurality of air passage orifices (113) distributed circumferentially around the axis (X), each orifice (113) being delimited by two opposing circumferential ends (116, 117) and by two opposing axial ends (114, 115), the circumferential ends (116, 117) of each orifice (113) defining between themselves a first extension dimension (120) of said orifice (113) and the axial ends (114, 115) of each orifice (113) defining between themselves a second extension dimension of said orifice (113), and wherein, for each orifice (113), on the one hand, the first the extension dimension (120) of the orifice (113) has a maximum dimension that is greater than a maximum dimension of the second extension dimension of the orifice (113) and, on the other hand,each of the two circumferential ends (116, 117) is connected to the two axial ends (114, 115) by a respective rounded junction portion (124, 125, 126, 127), and wherein the connecting wall (112) has a downstream diameter and an upstream diameter, the downstream diameter being greater than the upstream diameter, and wherein the first extension dimension (120) of each orifice (113) is decreasing from a respective downstream end (121) of the two circumferential ends (116, 117) of said orifice (113) to a respective upstream end (122) of the two circumferential ends (116, 117) of said orifice (113).

2. Trunnion according to claim 1, wherein the connecting wall (112) is frustoconical.

3. Trunnion according to claim 1 or 2, in which the orifices (113) are distributed circumferentially in a regular manner around the axis (X).

4. Trunnion according to any one of claims 1 to 3, wherein the first extension dimension (120) of each orifice (113) is less than or equal to a circumferential distance (123) separating said orifice (113) from another circumferentially adjacent orifice (113).

5. Trunnion according to any one of claims 1 to 4, wherein each orifice (113) is symmetrical with respect to an axial plane of the trunnion (109).

6. Trunnion according to any one of claims 1 to 5, wherein at least one of the two axial ends (114, 115) of each orifice (113) extends in a plane perpendicular to the axis (X).

7. Trunnion according to claim 6, in which each orifice (113) has two circumferentially opposed upstream junction portions (126, 127) and two circumferentially opposed downstream junction portions (124, 125), each of said junction portions (124, 125, 126, 127) connecting one of the two circumferential ends (116, 117) to one of the two axial ends (114, 115), said junction portions (124, 125, 126, 127) extending along arc portions of a circle.

8. Trunnion according to any one of claims 1 to 7, wherein at least one of the two circumferential ends (116, 117) of each orifice (113) is straight.

9. Trunnion according to any one of claims 1 to 8, wherein at least one of the upstream end and the downstream end of the trunnion extends radially in projection so as to form a trunnion fixing flange.

10. Aircraft turbomachine comprising a casing extending about an axis (X), a turbomachine shaft, a turbine rotor shaft and a trunnion according to any one of claims 1 to 9, the turbomachine shaft, the turbine rotor shaft and the trunnion being rotatably mounted about the axis (X) and the trunnion being fixed, preferably by bolting, on one side to the upstream end of the trunnion to the turbomachine shaft, and on the other side, to the downstream end of the trunnion to the turbine rotor shaft.

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