JP3944206B2 - Shaft seal mechanism - Google Patents

Description

  The present invention relates to a shaft seal mechanism for a rotating shaft of a large fluid machine such as a gas turbine, a steam turbine, a compressor, a water turbine, a refrigerator, a pump, and the like, and in particular, is coaxial with the peripheral surface of the rotating shaft and the rotating shaft. The present invention relates to a shaft seal mechanism that suppresses leakage of working fluid from a high pressure side to a low pressure side in a gap with an inner peripheral surface of a stationary member that is stationary.

  In general, in a large fluid machine such as a gas turbine or a steam turbine, in addition to a main flow channel that essentially flows a working fluid such as compressed air, combustion gas, or steam (hereinafter sometimes simply referred to as “gas”), It is unavoidable that an annular gap is formed between the peripheral surface of the rotating shaft and the inner peripheral surface of a stationary member that is coaxial and stationary on the rotating shaft (for example, an annular member that holds the inner peripheral end of the stationary blade). Absent. If no measures are taken with respect to the gap, gas leaks inadvertently from the high-pressure side to the low-pressure side through the gap, resulting in a decrease in the efficiency of the fluid machine. Therefore, it is extremely important to minimize gas leakage through the gap, and in order to realize this, a shaft seal mechanism is applied to the gap.

  As the shaft seal mechanism, a non-contact type so-called labyrinth seal in which a plurality of fins protrude from the inner peripheral surface of a stationary member has been widely used. However, the labyrinth seal must be configured so that the tip of the fin does not come into contact with the peripheral surface of the rotating shaft even during axial vibration or thermal transient thermal deformation during the rotational transition period. As a result, there is a problem that gas leakage cannot be greatly suppressed.

  On the other hand, in recent years, as a shaft seal mechanism that can significantly reduce the amount of gas leakage, a so-called leaf seal having a structure in which flat thin plates having a certain width in the axial direction of the rotating shaft are arranged in the circumferential direction of the rotating shaft is provided. Yes (see, for example, Patent Document 1). Hereinafter, the detailed structure of the leaf seal will be described with reference to FIGS. Here, as a large-sized fluid machine to which a leaf seal is applied, a typical gas turbine will be described as an example.

  A gas turbine Gt shown in FIG. 8 includes a compressor 1 that takes in a large amount of air and compresses it, a combustor 2 that mixes and burns fuel into the air compressed by the compressor 1, and a combustor 2. The generated high-temperature and high-pressure combustion gas is introduced into the turbine 3 that converts the thermal energy of the combustion gas into rotational energy, and the rotation that directly receives the rotational energy of the turbine 3 and transmits a part of it as power for the compressor 1. And a shaft 4.

  In the turbine 3, a plurality of moving blades 10 provided in a plurality of stages in the axial direction on the rotating shaft 4 rotate together with the rotating shaft 4 by receiving the pressure of the sprayed combustion gas. Thus, power is generated by converting the thermal energy of the combustion gas into mechanical rotational energy called rotation of the rotating shaft 4. The rotational energy given to the rotating shaft 4 is taken out from the shaft end and used for power generation. In addition to the moving blade 10 on the rotating shaft 4 side, the turbine 3 is provided with a plurality of stationary blades 11 on the casing 9 side of the turbine 3, and the moving blade 10 and the stationary blade 11 are connected to the rotating shaft. 4 are arranged alternately in the axial direction. The amount of combustion gas that leaks from the high pressure side to the low pressure side through the gap between the rotating shaft 4 and the stationary blade 11 (actually, an annular stationary member that holds the inner peripheral end of the stationary blade 11). A leaf seal 20 is provided as a shaft seal mechanism for reducing the above.

  The compressor 1 is coaxially connected to the turbine 3 at the rotating shaft 4, and uses the rotation of the rotating shaft 4 in the turbine 3 to suck and compress outside air into the combustor 2. Supply. In the compressor 1, similarly to the turbine 3, a plurality of moving blades 6 are provided on the rotating shaft 4, and a plurality of stationary blades 7 are provided on the casing 5 side of the compressor 1. The rotating shafts 4 are alternately arranged in the axial direction. The compressed air leaking from the high pressure side to the low pressure side through the gap between the rotating shaft 4 and the stationary blade 7 (here, actually, an annular stationary member that holds the inner peripheral end of the stationary blade 7). A leaf seal 20 is provided as a shaft seal mechanism for reducing the amount of leakage.

  Further, in the bearing portion 8 where the casing 5 of the compressor 1 supports the rotating shaft 4 and the bearing portion 12 where the casing 9 of the turbine 3 supports the rotating shaft 4, compressed air or A leaf seal 20 is provided as a shaft seal mechanism for preventing combustion gas from leaking.

  Subsequently, as shown in FIGS. 9 and 10, the leaf seal 20 is inserted into the stator 60, which is a stationary member corresponding to the stationary blades 7 and 11 and the bearing portion 912 (see FIG. 8). It is installed as a shaft seal mechanism for preventing gas leakage in the annular space in the gap between the surface and the inner peripheral surface of the stator 60. The leaf seal 20 includes an annular thin plate group composed of a plurality of thin plates 21 (see FIG. 11 (a)) that are stacked in multiple layers in the circumferential direction of the rotating shaft 4 with a minute gap therebetween, and the thin plate group is formed into a thin plate 21. Each of the U-shaped retainers 22 and 23 sandwiched from both sides in the axial direction on the outer peripheral proximal end side, and one side and one retainer 22 located on the high pressure side (the gas pressure side) in the thin plate group The thin plate group is sandwiched between the divided annular high-pressure side plate 24 that is sandwiched and contacts one side of the thin plate group, the other side located on the low-pressure side (the low gas pressure side) of the thin plate group, and the other retainer 23. Of the divided annular low-pressure side plate 25 in contact with the other side, the connecting member 26 that connects the retainers 22 and 23 on the outer peripheral side of the thin plate 21, and rattling of the thin plates 21 held by the retainers 22 and 23. Spacer 27 to suppress Comprises a leaf spring 28 which sheet group that is grasped by the retainer 22, 23 provide a biasing force to be constant position with respect to the rotation axis 4, a.

  As shown in FIG. 10, each thin plate 21 that is a constituent element of the thin plate group has a substantially T-shaped thin shape in which the width in the axial direction of the rotary shaft 4 at the outer peripheral side base end is wider than the width at the inner peripheral end side. It is made of a steel plate, and on both sides thereof, notches 21a and 21b are provided at the stepped portions of the width. Here, each thin plate 21 is made of a rolled steel plate having a thickness of about 0.1 mm (for example, a metal steel plate made of stainless steel, Inconel, Hastelloy, etc.), and is first die-cut with a press or the like to obtain a constant thickness. It is molded into a predetermined shape (T-shape). Then, as shown in FIG. 12, the thickness of the thin plate 21 is removed by etching and removing only one side (corresponding to the shaded portion 21d in FIG. 12) of the inner peripheral end side while leaving the outer peripheral base end portion as it is. A step is formed. However, it is also possible to simultaneously form such T-shaped contour formation and step formation by etching.

  Such thin plates 21 are stacked so as to have the same width in the axial direction of the rotary shaft 4 and, as shown in FIG. 11B, welded to the side surfaces of the outer peripheral base end and the wide portion serving as the outer peripheral base end side. Wd is applied and fixed, whereby a thin plate group is formed. In addition, each thin plate 21 is designed to have a predetermined rigidity in the circumferential direction of the rotating shaft 4 determined by the etched thickness t on the inner peripheral end side, and the rotating shaft 4 with respect to the rotating direction of the rotating shaft 4. Is held by retainers 22 and 23 so that the angle θ formed with the peripheral surface of the above becomes an acute angle. In the thin plate group, the depth c of the portion 21d removed by etching of each thin plate 21 is a minute gap between the thin plates 21.

  The high-pressure side plate 24 and the low-pressure side plate 25 are provided with protrusions 24a and 25a that protrude in the axial direction of the rotary shaft 4 at the outer peripheral edge portions, and these protrusions 24a and 25a are notches of the thin plate group. The parts 21a and 21b are respectively fitted. Further, the retainer 22 located on the high pressure side has a concave groove 22a on the surface facing the one side which is the high pressure side on the outer peripheral base end side in the thin plate group, and the retainer 23 located on the other low pressure side is in the thin plate group. A groove 23a is provided on the surface facing the other side which is the low pressure side on the outer peripheral base end side. In the thin plate group in which the protrusions 24a and 25a of the high-pressure side plate 24 and the low-pressure side plate 25 are fitted into the notches 21a and 21b, one side which is the high-pressure side on the outer peripheral base end side is the concave groove 22a of the retainer 22. And the other side, which is the low-pressure side of the outer peripheral base end side, is fitted into the recessed groove 23 a of the retainer 23.

  Here, the inner diameter of the high-pressure side plate 24 is slightly larger than the diameter of the rotating shaft, and the inner diameter of the low-pressure side plate 25 is larger than the inner diameter of the high-pressure side plate 24 by a predetermined amount. Accordingly, the inner peripheral end portion of each thin plate 21 in the thin plate group has a much larger exposed area in the axial direction on the other side, which is the low pressure side, than one side, which is the high pressure side.

  A connecting member 26 is inserted between the retainers 22 and 23 in which the outer peripheral proximal end side of the thin plate group is fitted, and the connecting members 26 are welded to the retainers 22 and 23 so that the retainers 22 and 23 are fixed. Is done. A spacer 27 is inserted between the outer peripheral proximal end of the thin plate group and the retainers 22 and 23 to fill the gap between them. Furthermore, concave grooves 22b and 23b are provided on the outer peripheral sides of the retainers 22 and 23 into which the spacers 27 are inserted, and a leaf spring 28 is fitted into one concave groove formed by the concave grooves 22b and 23b. As a result, the leaf spring 28 is fixed to the outer peripheral side of the retainers 22 and 23.

  As shown in FIG. 10, the leaf seal 20 having such a configuration is an annular mounting groove formed integrally with a split annular mounting piece 62 and formed along the circumferential direction on the inner peripheral wall surface on the stator 60 side. 61 is fitted along the circumferential direction from the retainers 22 and 23 side. Here, the concave groove 61 is formed on the side surface facing the one side which is the high pressure side of the thin plate group so that the width on the outer peripheral side serving as the bottom is wider than the width on the inner peripheral side in the axial direction of the rotation shaft 4. The shape is provided with a step, and the surface 61 a on the outer peripheral side of the step is a sliding contact surface that is in sliding contact with the inner peripheral surface of the retainer 22 of the leaf seal 20. Further, the outer peripheral surface 61 b that is the bottom of the concave groove 61 is a sliding contact surface that comes into sliding contact with the leaf spring 28 provided on the outer peripheral side of the leaf seal 20. Further, the inner circumferential side width of the concave groove 61 is formed to be sufficiently wider than the width of the leaf seal 20 in the axial width of the rotating shaft 4.

  On the other hand, as shown in FIG. 10, in the axial direction of the rotating shaft 4, the mounting piece 62 is connected to the other side, which is the low pressure side of the thin plate group, so that the width on the outer peripheral side is narrower than the width on the inner peripheral side. A step is provided on the opposite side surface, and the outer surface 62a of the step is a sliding contact surface that is in sliding contact with the inner peripheral surface of the retainer 23 of the leaf seal 20. Further, in the mounting piece 62, the side surface 62 b facing the other side which is the low pressure side of the thin plate group is in contact with the low pressure side plate 25 in the wide inner peripheral side portion in the axial direction of the rotating shaft 4. It becomes the pressure receiving surface. Note that a labyrinth seal 62d is provided by projecting a part of the inner peripheral surface of the mounting piece 62. That is, the mounting piece 62 is installed on the downstream side of the leaf seal 20, and thereby, the labyrinth seal 62 d for further reducing the amount of gas leakage is installed downstream of the leaf seal 20.

  As described above, the leaf seal 20 is held together with the mounting piece 62 on the outer peripheral proximal end side with respect to the concave groove 61 of the stator 60. That is, the inner peripheral surfaces of the retainers 22 and 23 are in sliding contact with the sliding contact surface 61a of the recessed groove 61 and the sliding contact surface 62a of the mounting piece 62, and are fixed to the outer peripheral side of the retainers 22 and 23. Is in sliding contact with the sliding contact surface 61 b of the concave groove 61, so that the leaf seal 20 is maintained in a state of being fitted to the stator 60. Incidentally, since the leaf seal 20 is fitted into the concave groove 61 of the stator 60 using the mounting piece 62, the assembling work can be easily performed.

  At this time, the leaf seal 20 can move slightly in the axial direction of the rotary shaft 4 with respect to the inside of the concave groove 61. Therefore, when gas flows from the high pressure side region toward the low pressure side region, the gas pressure acts on each thin plate 21 of the leaf seal 20, so that the leaf seal 20 moves toward the low pressure side region, as will be described later. The low-pressure side plate 25 comes into contact with the pressure receiving surface 62 b of the mounting piece 62.

  Next, the operation of the leaf seal 20 configured as described above will be described. As shown in FIG. 13A, when a gas pressure from the high pressure side region toward the low pressure side region is applied to each thin plate 21, it is located on the inner peripheral end side and the highest pressure side region with respect to each thin plate 21. A gas pressure distribution 70a is formed in which the gas pressure is highest at the corner r1 and the gas pressure gradually decreases toward the diagonal corner r2. In FIG. 10, each thin plate 21 has a T-shape. However, in FIG. 9 and FIG. 13, only a rectangular portion that causes bending is illustrated for convenience.

  Further, as shown in the cross-sectional view along the circumferential direction of the rotating shaft 4 shown in FIG. 13B, the surface facing the rotating shaft 4 of each thin plate 21 is a lower surface 21q, and the back side is an upper surface 21p. And when the gas pressure which goes to a low voltage | pressure side area | region from a high voltage | pressure side area | region is added with respect to each thin plate 21, and the gas pressure distribution 70a as shown to Fig.13 (a) is formed, arbitrary along the cross section of each thin plate 21 The gas pressure is adjusted so that the gas pressure applied to the lower surface 21q is higher than the gas pressure applied to the upper surface 21p at the position.

  At this time, the gas g flowing from the high pressure side region toward the low pressure side region flows from between the high pressure side plate 24 and the peripheral surface of the rotating shaft 4. As shown in FIG. 13A, the gas g flows between the peripheral surface of the rotating shaft 4 and the inner peripheral end of the thin plate 21, and the gap between the upper surface 21p and the lower surface 21q of the adjacent thin plates 21. , And flows radially from the corner r1 to the corner r2. As the gas g flows in this manner, a low-pressure region expands toward the outer peripheral base end of each thin plate 21. Therefore, as shown in FIG. 13 (b), the gas pressure distributions 70b and 70c applied perpendicularly to the upper surface 21p and the lower surface 21q of each thin plate 21 become larger and closer to the inner peripheral end portion of each thin plate 21 and each thin plate 21. It becomes a triangular distribution shape that becomes smaller as it goes toward the outer periphery base end.

  The gas pressure distributions 70b and 70c on the upper surface 21p and the lower surface 21q have substantially the same shape, but the thin plates 21 are arranged so that the angle θ with respect to the peripheral surface of the rotating shaft 4 is an acute angle. The relative positions of the gas pressure distributions 70b and 70c on 21p and the lower surface 21q are shifted from the thin plate 21. Thereby, a difference arises in the gas pressure of the upper surface 21p and the lower surface 21q in the arbitrary points P which go to the inner peripheral end side from the outer peripheral base end side of the thin plate 21. Thus, in each thin plate 21, the gas pressure applied to the lower surface 21q is higher than the gas pressure applied to the upper surface 21p, so that the gas pressure of the gas flowing between the peripheral surface of the rotating shaft 4 and the inner peripheral end of the thin plate 21 is reduced. The inner peripheral edge of each thin plate 21 is generated in the direction of floating from the rotary shaft 4.

  In this manner, by generating a pressure difference between the upper surface 21p and the lower surface 21q of each thin plate 21, the inner peripheral end of each thin plate 21 is deformed so as to float above the peripheral surface of the rotating shaft 4. That is, when the rotation shaft 4 stops rotating, the inner peripheral end of the thin plate 21 is in contact with the peripheral surface of the rotation shaft 4 with a predetermined preload (see FIG. 11A), but when the rotation shaft 4 rotates, the rotation shaft 4 Since the inner peripheral end of the thin plate 21 is lifted by the dynamic pressure effect generated by the rotation, the thin plate 21 and the peripheral surface of the rotary shaft 4 are in a non-contact state (see FIG. 11C). Thus, the leaf seal 20 divides the space around the rotating shaft 4 into a high pressure side region and a low pressure side region, and seals the outer periphery of the rotating shaft 4.

  At this time, since the gas g flows from the high-pressure side region to the low-pressure side region in this way, as shown in FIG. 14 (a), the fluid force is applied from the high-pressure side region to the low-pressure side region. F acts. When the thin plate group receives the fluid force F, the leaf seal 20 moves from the high pressure side region toward the low pressure side region. And as shown in FIG.14 (b), the position of the leaf seal 20 is controlled when the low voltage | pressure side board 25 contact | abuts to the pressure receiving surface 62b of the piece 62 for attachment, At this time, it is the low voltage | pressure side in a thin-plate group. The distance between the other side and the pressure receiving surface 62 b of the mounting piece 62 is equal to the thickness of the low pressure side plate 25.

  This is because, since the inner diameter of the low-pressure side plate 25 is larger than the inner diameter of the thin plate group, there is an exposed area that does not contact the low-pressure side plate 25 on the inner peripheral end side of each thin plate 21 in the thin plate group. As a result, on the inner peripheral end side of each thin plate 21 in the thin plate group, a gap equal to the thickness of the low pressure side plate 25 is provided between the other side which is the low pressure side and the pressure receiving surface 62b of the mounting piece 62. It can be secured. On the other hand, since the inner diameter of the high-pressure side plate 24 is smaller than the inner diameter of the low-pressure side plate 25, as a result, on the inner peripheral end side of each thin plate 21 in the thin plate group, the exposed area on the high pressure side is the surface on the low pressure side. It becomes smaller than the departure area.

  Therefore, as shown in FIG. 13A, the gas g flowing into each thin plate 21 (thin plate group) through the gap between the inner peripheral surface of the high-pressure side plate 24 and the peripheral surface of the rotary shaft 4 is the upper surface 21p of each thin plate 21. And the lower plate 21q flows widely in a diagonal direction, and a low pressure region spreads on the outer peripheral proximal end side of the thin plate 21, so that the inner peripheral end of each thin plate 21 floats from the peripheral surface of the rotating shaft 4, It flows out through the gap between the inner peripheral surface of the side plate 25 and the peripheral surface of the rotating shaft 4. Thus, the high-pressure side plate 24 and the low-pressure side plate 25 are important for the leaf seal 20 that adjusts the amount of gas flowing into each thin plate 21 and the gas pressure in order to effectively float the inner peripheral end of each thin plate 21. Fulfills the functions.

  In the leaf seal 20 described above, each thin plate 21 has a T-shape, but may have a simple rectangular shape. Further, there may be no spacer 27 between the thin plate group and the retainers 22 and 23, or the retainers 22 and 23 and the connecting member 26 may be fixed with bolts, and there is no leaf spring 28. It does not matter.

Further, when the leaf seal 20 is assembled to a large fluid machine, it is difficult to insert the leaf seal 20 into the rotary shaft 4 along the axial direction in an annular state, so that the leaf seal 20 is annular along the peripheral surface of the rotary shaft 4. As shown in FIG. 15, the configured leaf seal 20 is actually composed of a plurality of divided bodies that are divided into 4 to 8 in the circumferential direction. At this time, the angle formed by each end face of each divided body with the circumferential surface of the rotating shaft 4 with respect to the rotation direction of the rotating shaft 4 is equal to the angle formed by each thin plate 21 with the circumferential surface of the rotating shaft 4.
JP 2002-13647 A

  By the way, when the leaf seal 20 is to be installed in the stator 60 where the pressure difference between the high pressure side region and the low pressure side region is extremely large, it is difficult for one leaf seal 20 to withstand the pressure difference. For this reason, the leaf seals 20 are installed in a plurality of stages in the axial direction of the rotary shaft 4, and the leaf seals 20 share the pressure difference. As an example, FIG. 16 shows a situation where the leaf seals 20 are installed in two stages. Here, a first-stage leaf seal 120 and a final-stage second-stage leaf seal 220 are installed in order from the high-pressure side region to the low-pressure side region.

  The first-stage leaf seal 120 includes a thin plate group in which a large number of thin plates 121 are stacked, a high-pressure side plate 124, and a low-pressure side plate 125 based on the basic structure of the leaf seal 20 described above. Similarly, the second-stage leaf seal 220 includes a thin plate group in which a large number of thin plates 221 are stacked, a high-pressure side plate 224, and a low-pressure side plate 225. It is held by retainers 223 and 224. On the inner peripheral surface of the stator 60, annular mounting grooves 161, 261 along the circumferential direction for mounting the first and second leaf seals 120, 220 are arranged at predetermined intervals in the axial direction of the rotary shaft 4. Open and formed. The first leaf seal 120 is integral with the split annular mounting piece 162 and is fitted in the concave groove 161 along the circumferential direction. Similarly, the second leaf seal 220 is separated from the split annular mounting piece 262. It is integrally fitted in the concave groove 261 along the circumferential direction. Thus, the first and second leaf seals 120 and 220 are fixed to the stator 60.

  As another example, as shown in FIG. 17, the first and second leaf seals 120 and 220 may be attached to the stator 60 with a split annular holder 90 interposed therebetween. In this case, an annular mounting groove 91 along the circumferential direction for mounting the holder 90 is formed on the inner peripheral surface of the stator 60. On the other hand, on the inner peripheral surface of the holder 90, annular mounting grooves 161, 261 along the circumferential direction for mounting the first and second leaf seals 120, 220, respectively, are arranged in the same manner as in FIG. 4 are formed at predetermined intervals in the axial direction. The first and second leaf seals 120, 220 are integrated with the split annular mounting pieces 162, 262, fitted in the concave grooves 161, 261 along the circumferential direction, and fixed to the holder 90. The holder 90 is fitted in the concave groove 91 along the circumferential direction. Thus, the first and second leaf seals 120 and 220 are fixed to the stator 60.

  However, in the installation mode of the multi-stage leaf seals 20 (first and second leaf seals 120 and 220) as described above, each of the leaf seals 20 has a somewhat wide groove 61 (recessed in the axial direction of the rotating shaft 4). In addition to providing the grooves 161, 261), it is necessary to ensure a certain amount of space between the concave grooves 61, that is, a certain amount of space is required between the leaf seals 20, so that it is inevitably rotated. The axis 4 also becomes longer. If it does so, the enlargement to the axial direction of the fluid machine to which this is applied will be caused, and there exists a bad effect that it becomes sensitive also to generation | occurrence | production of the axial vibration of the rotating shaft 4. This problem becomes more prominent as the number of installation stages of the leaf seal 20 is increased.

  However, if each of the leaf seals 20 can be attached to the stator 60 or the holder 90 as a single unit, the width of the mounting piece 62 (the mounting pieces 162 and 262) in the partial axis direction should be able to be suppressed. is there. However, in reality, it is almost impossible to form a concave groove capable of accommodating the leaf seal 20 having a specific shape along the circumferential direction. After all, as described above, the concave groove 61 is formed in a wide range with a reasonable degree of processing, and the gap with the leaf seal 20 is filled by holding the mounting piece 62.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a shaft seal mechanism including a plurality of stages of leaf seals and capable of suppressing the length of a rotating shaft. It is what.

  In order to achieve the above object, the shaft seal mechanism according to the present invention provides a working fluid from a high pressure side to a low pressure side in a gap between a peripheral surface of a rotating shaft and an inner peripheral surface of a stationary member that is coaxial and stationary on the rotating shaft. A shaft seal mechanism that suppresses leakage of the rotary shaft, and has a certain width in the axial direction of the rotary shaft, and each of them has an acute angle with respect to the peripheral surface of the rotary shaft with a small gap therebetween in the circumferential direction of the rotary shaft. An annular thin plate group consisting of a plurality of flexible thin plates whose inner peripheral ends are in contact with the peripheral surface of the rotating shaft when rotation is stopped, and both sides of the thin plate group in the axial direction. An annular high-pressure side plate that has an inner diameter that is a predetermined amount larger than the diameter of the rotary shaft, and that is located on the low-pressure side of both sides in the axial direction of the thin plate group. A predetermined amount larger than the inner diameter of the high-pressure side plate. An axial low-pressure side plate having a diameter, an annular holding member that integrally holds the thin plate group, the high-pressure side plate, and the low-pressure side plate at their outer peripheral portions, and a shaft seal that can be divided in the circumferential direction. The shaft sealing mechanism in which a plurality of members are axially attached to the stationary member in the axial direction is characterized by the following points.

As a first feature point, a mounting groove is formed on the inner peripheral surface of the stationary member along the circumferential direction, and the mounting member is shared between the shaft seal members of the adjacent stages. The seal members and the attachment members are integrally fitted in the attachment grooves along the circumferential direction and fixed to the stationary member, and the seal members are for the attachments. It is movable in the axial direction with respect to the member .

  In this way, only one mounting groove for mounting a plurality of shaft seal members, that is, leaf seals, to the stationary member is required, and the interval between the leaf seals in the axial direction of the rotating shaft is shared by both. Just enough to fit the mounting member. Therefore, the interval between the leaf seals adjacent to each other can be greatly reduced. Of course, when the mounting groove is formed on the stationary member, the width thereof is a dimension that includes all of the leaf seal and the mounting member that are sufficiently acceptable for processing, and therefore there is no hindrance to the processing.

Here, from the viewpoint of securing the stability of the fixed state of the leaf seal and the mounting member with respect to the stationary member, each of the mounting members may be fastened and fixed to the stationary member with a bolt penetrating in the radial direction. preferable. From the same point of view, each of the mounting members has an axial auxiliary projection formed on the outer peripheral surface along the circumferential direction and fitted in an auxiliary groove formed on the bottom of the mounting groove along the circumferential direction. It may be fixed together.

As a second feature point, an intermediate mounting member in which a mounting groove along the circumferential direction is formed on the inner peripheral surface of the stationary member, and an intermediate mounting groove along the circumferential direction is formed on the inner peripheral surface; A common mounting member between the shaft seal members of the adjacent stages, and the seal member and the mounting member are integrated with the intermediate mounting groove in the circumferential direction. The intermediate mounting member fixed to the intermediate mounting member and fixed to the intermediate mounting member is fixed to the mounting groove along the circumferential direction. The seal members are fixed to a stationary member, and the seal members are movable in the axial direction with respect to the attachment members .

  In this way, a plurality of shaft seal members, i.e., leaf seals, are attached to the stationary member with the intermediate attachment member interposed therebetween, but there are mounting grooves for attaching these leaf seals to the intermediate attachment member. The distance between the leaf seals in the axial direction of the rotating shaft is sufficient so that a common mounting member can be accommodated in both. Therefore, the interval between the leaf seals adjacent to each other can be greatly reduced. Of course, when the mounting groove is formed in the intermediate mounting member, the width thereof is a dimension including all the leaf seals and mounting members that are sufficiently acceptable for processing, and therefore there is no problem in the processing.

Here, from the viewpoint of ensuring the stability of the fixed state of the leaf seal and the mounting member with respect to the stationary member, each of the mounting members passes through the intermediate mounting member in the radial direction while the head is positioned on the stationary member side. It is preferable that the bolts are fastened and fixed. From the same point of view, each of the mounting members may be fastened and fixed by a bolt that penetrates the intermediate mounting member in the axial direction, and each of the mounting members is arranged on the outer peripheral surface along the circumferential direction. The axial auxiliary protrusion formed in this manner may be fitted and fixed to the intermediate auxiliary groove formed along the circumferential direction at the bottom of the intermediate mounting groove.

  According to the shaft seal mechanism of the present invention, the distance between the leaf seals adjacent to each other in the axial direction of the rotating shaft can be significantly suppressed, and accordingly, the length of the rotating shaft can be suppressed. The size of the fluid machine to which the leaf seal is applied is not increased in the axial direction.

  Hereinafter, a shaft seal mechanism employing a leaf seal as an embodiment of the present invention will be described in detail with reference to the drawings. First, a first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view taken along the axial direction of a rotary shaft, showing the main part of a large fluid machine having a plurality of leaf seals according to the first embodiment. In the figure, parts having the same names and the same functions as those in FIGS. 8 to 17 are denoted by the same reference numerals, and redundant description will be omitted as appropriate, and feature points of the present invention will be noted. In particular, in this embodiment, the case where the leaf seals 20 are installed in two stages is shown as an example. The same applies to the second to seventh embodiments described later.

  As shown in FIG. 1, the stator 60 includes a first-stage leaf seal 120 and a second-stage second stage in order from the high-pressure side region to the low-pressure side region along the axial direction of the rotating shaft 4. An eye leaf seal 220 is installed. On the inner peripheral surface of the stator 60, only one annular mounting concave groove 81 is formed along the circumferential direction for mounting the first and second leaf seals 120, 220. The first and second leaf seals 120 and 220 are integrally fitted into the recessed groove 81 along the circumferential direction, integrally with a split annular mounting piece 182 sandwiched between them in the axial direction.

  Here, the concave groove 81 is on the high-pressure side of the thin plate group in the first leaf seal 120 so that the width on the outer peripheral side serving as the bottom is wider than the width on the inner peripheral side in the axial direction of the rotating shaft 4. A step is provided on the side facing the one side, and a step is provided on the side facing the other side which is the low pressure side of the thin plate group in the second leaf seal 220 which is the final stage. Of these steps, the outer peripheral surface 81a of the step located toward the high-pressure side region becomes a slidable contact surface that makes sliding contact with the inner peripheral surface of the retainer 122 of the first leaf seal 120, and toward the low-pressure side region. The surface 81e on the outer peripheral side of the step that is positioned serves as a sliding contact surface that is in sliding contact with the inner peripheral surface of the retainer 223 of the second leaf seal 220 that is the final step. Furthermore, a side surface 81 g facing the other side which is the low pressure side of the thin plate group in the second leaf seal 220 which is the final stage is a pressure receiving surface which comes into contact with the low pressure side plate 225.

  Further, an auxiliary ditch 81c is formed on the bottom of the ditch 81 so as to be fitted to an auxiliary projection 182c formed along the circumferential direction on the outer peripheral surface of the mounting piece 182. The outer peripheral surface 81b positioned on the high-pressure side is a sliding contact surface that is in sliding contact with the leaf spring 128 provided on the outer peripheral side of the first leaf seal 120, and the outer peripheral surface 81f positioned on the other low-pressure side is the first It becomes a sliding contact surface in sliding contact with a leaf spring 228 provided on the outer peripheral side of the second leaf seal 220 adjacent to the leaf seal 120.

  On the other hand, the mounting piece 182 is arranged so that, in the axial direction of the rotary shaft 4, the width on the outer peripheral side is narrower than the width on the inner peripheral side. A step is provided on the opposite side surface, and a step is provided on the side surface facing the high pressure side of the thin plate group in the second leaf seal 220 as the final stage. Of these steps, the outer peripheral surface 182a of the step located toward the high-pressure side region becomes a sliding contact surface that is in sliding contact with the inner peripheral surface of the retainer 123 of the first leaf seal 120, and toward the low-pressure side region. The surface 182e on the outer peripheral side of the step is located as a sliding contact surface that is in sliding contact with the inner peripheral surface of the retainer 222 of the second leaf seal 220 adjacent to the first leaf seal 120. Furthermore, the mounting piece 182 has a side surface 182b facing the other side which is the low pressure side of the thin plate group in the first leaf seal 120 in the wide inner peripheral side portion in the axial direction of the rotating shaft 4. The pressure receiving surface comes into contact with the low pressure side plate 125.

  Thus, the mounting piece 182 is shared by the first and second leaf seals 120, 220 that are axially adjacent to each other, and the first and second leaf seals 120, 220, together with the shared mounting piece 182, The groove 60 of the stator 60 is held on the outer peripheral base end side. That is, the inner peripheral surfaces of the retainers 122 and 123 are in sliding contact with the sliding contact surface 81 a of the concave groove 81 and the sliding contact surface 182 a of the mounting piece 182, and are fixed to the outer peripheral side of the retainers 122 and 123. Is in sliding contact with the sliding contact surface 81b of the concave groove 81, and on the other hand, the inner peripheral surfaces of the retainers 222 and 223 are in sliding contact with the sliding contact surface 182e of the mounting piece 182 and the sliding contact surface 81e of the concave groove 81, respectively. A state in which the first and second leaf seals 120 and 220 are fitted into the stator 60 by the leaf spring 228 fixed to the outer peripheral side of the retainers 222 and 223 being in sliding contact with the sliding contact surface 81f of the concave groove 81. Maintained at.

  The common mounting piece 182 is fixed to the stator 60 by fastening bolts 183 penetrating radially outward from the inner peripheral surface thereof, so that the first and second leaf seals 120 and 220 are fixed to the stator 60. Fixed to. Thereby, the fixed state of the leaf seals 120 and 220 and the mounting piece 182 with respect to the stator 60 can be secured sufficiently stably.

  With this configuration, only one mounting concave groove 81 for mounting the first and second leaf seals 120 and 220 to the stator 60 is required, and the leaf seal 120 in the axial direction of the rotating shaft 4 is sufficient. , 220 is sufficient to accommodate a common mounting piece 182 for both. Therefore, the interval between the leaf seals 120 and 220 adjacent to each other can be greatly suppressed, and accordingly, the length of the rotating shaft 4 can be suppressed, resulting in an increase in the size of the fluid machine in the axial direction. There is nothing. Further, when forming the mounting recessed groove 81 in the stator 60, the width thereof is a dimension including all of the leaf seals 120, 220 and the mounting piece 182. There is no hindrance.

  Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a cross-sectional view along the axial direction of the rotary shaft showing the main part of a large fluid machine having a plurality of leaf seals according to the second embodiment. In the figure, the same reference numerals are given to the portions having the same names and the same functions as those in FIG. The same applies to third to seventh embodiments described later. The feature of the second embodiment is that the method for fixing the mounting piece 182 in the first embodiment is modified.

  That is, in this embodiment, as shown in FIG. 2, there is an auxiliary groove 81 c formed in the bottom of the groove 81 of the stator 60 and has a groove shape, and the auxiliary groove 81 c has an auxiliary piece 182 for assisting the mounting piece 182. By fitting the protrusion 182c along the circumferential direction, the attachment piece 182 is fixed to the stator 60 together with the first and second leaf seals 120 and 220 as they are.

  Even in this case, the fixed state of the leaf seals 120 and 220 and the mounting piece 182 to the stator 60 can be secured sufficiently stably. In addition, in this case, since the bolt 183 as in the first embodiment is not required at all, it is advantageous for reduction of manufacturing costs related to parts procurement and assembly man-hours, and the bolt 183 that can be generated with the operation of the fluid machine. Since there is no fear of falling off due to loosening of the fluid, it is advantageous for ensuring the performance of the fluid machine.

  Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view along the axial direction of the rotating shaft showing the main part of a large fluid machine having a plurality of leaf seals according to the third embodiment. The feature of the third embodiment is that the number of parts is reduced compared to the first and second embodiments. FIG. 3 shows a modification of the second embodiment.

  That is, in the present embodiment, as shown in FIG. 3, the first leaf seal 120 located toward the high-pressure side region of the first and second leaf seals 120 and 220 adjacent to the common mounting piece 182. The retainer 123 on the low-pressure side, which is a component of the above, is formed integrally with the mounting piece 182 so that the function of the retainer 123 is also used as the mounting piece 182. Thereby, the retainer 123 as a part can be reduced and it is advantageous in economical efficiency.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view along the axial direction of the rotary shaft showing the main part of a large-sized fluid machine having a plurality of stages of leaf seals in the fourth embodiment. The feature of the fourth embodiment is that the first and second leaf seals 120 and 220 in the first embodiment are attached to the stator 60 with a split annular holder 90 interposed therebetween.

  That is, in this embodiment, as shown in FIG. 4, an annular mounting groove 91 is formed on the inner peripheral surface of the stator 60 along the circumferential direction for mounting the holder 90. On the other hand, on the inner peripheral surface of the holder 90, there is one annular mounting groove 81 along the circumferential direction for mounting the first and second leaf seals 120 and 220, as in the first embodiment. Only formed. The first and second leaf seals 120 and 220 are integrated with the common mounting piece 182 and are fitted in the concave groove 81 of the holder 90 along the circumferential direction. Subsequently, the common mounting piece 182 is fixed to the holder 60 by fastening bolts 183 penetrating radially inward from the outer peripheral surface of the holder 90, whereby the first and second leaf seals 120, 220 are secured. It is fixed to the holder 60 in a sufficiently stable state. The holder 90 is fitted in the concave groove 91 of the stator 60 along the circumferential direction. Thus, the leaf seals 120 and 220 and the mounting piece 182 are attached to the stator 60.

  With this configuration, the first and second leaf seals 120 and 220 are attached to the stator 60 with the holder 90 interposed therebetween. However, as in the first embodiment, these leaf seals 120 and 220 are attached. The mounting groove 81 for attaching the holder 90 to the holder 90 is sufficient, and the spacing between the leaf seals 120 and 220 in the axial direction of the rotary shaft 4 is such that the common mounting piece 182 fits in both. It ’s enough. Therefore, the interval between the leaf seals 120 and 220 adjacent to each other can be greatly suppressed, and accordingly, the length of the rotating shaft 4 can be suppressed, resulting in an increase in the size of the fluid machine in the axial direction. There is nothing. Further, when the mounting concave groove 81 is formed in the holder 90, the width thereof is a dimension including all of the leaf seals 120 and 220 and the mounting piece 182. There is no hindrance.

  In particular, in the present embodiment, the bolt 183 that fastens the mounting piece 182 to the holder 90 is housed in the concave groove 81 of the stator 60, so that even if the bolt 183 is loosened greatly, it does not fall off. In the same manner as in the first embodiment described above, the mounting piece 182 may be fastened to the holder 90 with a bolt 183 that penetrates radially outward from the inner peripheral surface of the mounting piece 182.

  Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view along the axial direction of the rotary shaft showing the main part of a large fluid machine having a plurality of leaf seals according to the fifth embodiment. The feature of the fifth embodiment is that the fastening method using the bolt 183 of the mounting piece 182 in the fourth embodiment is modified.

  That is, in this embodiment, as shown in FIG. 5, the mounting piece 182 fitted in the concave groove 81 of the holder 90 is fastened by a bolt 183 that penetrates from the side surface of the holder 90 along the axial direction of the rotary shaft 4. It is fixed to the holder 60.

  Even in this case, the fixed state of the leaf seals 120 and 220 and the mounting piece 182 to the holder 90 can be secured sufficiently stably. In this case, the diameter of the bolt 183 can be increased so as to increase the allowable strength that the bolt 183 can bear. Therefore, even if the required number is reduced, the mounting piece 182 for the holder 90 can be stably mounted. Fixing can be secured sufficiently. This is because in the fastening with the bolt 183 in the radial direction as in the fourth embodiment, the expansion of the diameter of the bolt 183 is limited due to the space restriction in the axial direction of the rotary shaft 4.

  Next, FIGS. 6 and 7 show sixth and seventh embodiments of the present invention. 6 and 7 are cross-sectional views along the axial direction of the rotary shaft showing the main part of a large-sized fluid machine provided with a plurality of leaf seals in the sixth and seventh embodiments, respectively. In the sixth embodiment, as shown in FIG. 6, the fixing method of the mounting piece 182 in the fourth and fifth embodiments is modified in the same manner as the modification of the second embodiment with respect to the first embodiment. is doing. In the seventh embodiment, as shown in FIG. 7, the number of parts for the fourth and fifth embodiments is the same as the modification of the third embodiment for the first and second embodiments. We are trying to reduce it.

  In each of the above-described embodiments, the configuration in which the leaf seals 20 are installed in two stages has been described, but three or more stages may be used. In that case, it is only necessary to provide the attachment pieces 182 between the leaf seals 20 adjacent to each other.

  In addition, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, although the thing which employ | adopted the leaf seal is illustrated in the gas turbine shown in FIG. 8, it is not limited to it, Large-sized fluid machinery, such as a steam turbine, a compressor, a water turbine, a refrigerator, a pump, is shown. As described above, it can be widely used for converting energy into work depending on the relationship between the rotation of the shaft and the flow of working fluid. It can also be used to suppress the flow of the working fluid in the axial direction along the peripheral surface of the rotating shaft.

  The present invention is useful as a shaft seal mechanism for a rotating shaft of a large fluid machine.

It is sectional drawing which follows the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the leaf seal in multiple steps in 1st Embodiment of this invention. It is sectional drawing which follows the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the leaf seal in 2nd Embodiment of this invention. It is sectional drawing in alignment with the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the leaf seal in 3rd Embodiment of this invention. It is sectional drawing which follows the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the multi-stage leaf seal in 4th Embodiment of this invention. It is sectional drawing in alignment with the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the leaf seal in 5th Embodiment of this invention. It is sectional drawing which follows the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the leaf seal in 6th Embodiment of this invention. It is sectional drawing which follows the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the leaf seal in 7th Embodiment of this invention. It is the schematic which shows the structure of the gas turbine which is an example of the large sized fluid machine provided with the conventional general leaf seal. It is a perspective view which shows the basic composition of the conventional general leaf seal. It is sectional drawing which follows the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the conventional general leaf seal. It is the side view and sectional drawing which follow the circumferential direction of the rotating shaft which shows the basic composition of the conventional general leaf seal. It is a side view of the thin plate which is a component of the conventional general leaf seal. It is a schematic diagram for demonstrating the effect | action of the conventional general leaf seal. It is a schematic diagram for demonstrating the effect | action of the conventional general leaf seal. It is a top view which shows the state which has arrange | positioned the conventional general leaf seal in cyclic | annular form. It is sectional drawing in alignment with the axial direction of the rotating shaft which shows the principal part of the large sized fluid machine provided with the conventional leaf seal in multiple steps. It is sectional drawing in alignment with the axial direction of the rotating shaft which shows the principal part of the other large sized fluid machine provided with the multi-stage leaf seal in the past.

Explanation of symbols

4 Rotating shaft 20, 120, 220 Leaf seal 21, 121, 221 Thin plate 22, 23, 122, 123, 222, 223 Retainer 24, 124, 224 High pressure side plate 25, 125, 225 Low pressure side plate 28, 128, 228 Plate Spring 60 Stator 61, 81 Mounting groove 90 Holder 91 Mounting groove 182 Mounting piece 183 Bolt

Claims (7)

A shaft seal mechanism that suppresses leakage of working fluid from the high pressure side to the low pressure side in the gap between the peripheral surface of the rotating shaft and the inner peripheral surface of a stationary member that is coaxial and stationary with respect to the rotating shaft,
Each inner peripheral end rotates while having a certain width in the axial direction of the rotating shaft and being stacked at an acute angle with respect to the peripheral surface of the rotating shaft, with each having a small gap in the circumferential direction of the rotating shaft. An annular thin plate group consisting of a large number of flexible thin plates that come into contact with the peripheral surface of the rotating shaft when stopped, and one side located on the high pressure side of both sides of the thin plate group in the axial direction. An annular high-pressure side plate having an inner diameter larger than the diameter of the rotary shaft by contact with the other side located on the low-pressure side of both sides of the thin plate group in the axial direction, and the inner diameter of the high-pressure side plate An annular low-pressure side plate having an inner diameter larger than a predetermined amount, an annular holding member that integrally holds the thin plate group, the high-pressure side plate, and the low-pressure side plate at their outer peripheral portions, in a circumferential direction. The separable shaft seal member is pivoted with respect to the stationary member. In the shaft sealing mechanism with several setup to direction,
A mounting groove along the circumferential direction is formed on the inner peripheral surface of the stationary member, and a common mounting member is provided between the shaft seal members of the adjacent stages.
The seal members and the mounting members are integrally fitted in the mounting grooves along the circumferential direction and fixed to the stationary member, and the seal members are pivoted with respect to the mounting members. A shaft seal mechanism that is movable in a direction .   2. The shaft seal mechanism according to claim 1, wherein each of the attachment members is fastened and fixed to the stationary member by a bolt that penetrates in a radial direction. Wherein each mounting member, the outer peripheral surface in the circumferential direction the axial direction of the auxiliary protrusions formed along the can, is fitted and fixed to an auxiliary groove formed along the circumferential direction on the bottom of the mounting groove The shaft seal mechanism according to claim 1, wherein A shaft seal mechanism that suppresses leakage of working fluid from the high pressure side to the low pressure side in the gap between the peripheral surface of the rotating shaft and the inner peripheral surface of a stationary member that is coaxial and stationary with respect to the rotating shaft,
Each inner peripheral end rotates while having a certain width in the axial direction of the rotating shaft and being stacked at an acute angle with respect to the peripheral surface of the rotating shaft, with each having a small gap in the circumferential direction of the rotating shaft. An annular thin plate group consisting of a large number of flexible thin plates that come into contact with the peripheral surface of the rotating shaft when stopped, and one side located on the high pressure side of both sides of the thin plate group in the axial direction. An annular high-pressure side plate having an inner diameter larger than the diameter of the rotary shaft by contact with the other side located on the low-pressure side of both sides of the thin plate group in the axial direction, and the inner diameter of the high-pressure side plate An annular low-pressure side plate having an inner diameter larger than a predetermined amount, an annular holding member that integrally holds the thin plate group, the high-pressure side plate, and the low-pressure side plate at their outer peripheral portions, in a circumferential direction. The separable shaft seal member is pivoted with respect to the stationary member. In the shaft sealing mechanism with several setup to direction,
A mounting groove is formed on the inner peripheral surface of the stationary member along the circumferential direction, and the intermediate mounting member is formed on the inner peripheral surface with an intermediate mounting groove along the circumferential direction. A common mounting member is provided between the shaft seal members,
The seal members and the attachment members are integrally fitted in the intermediate attachment grooves along the circumferential direction and fixed to the intermediate attachment members, and the seal members and the attachment members are fixed. The intermediate mounting member is fitted in the mounting groove along the circumferential direction and fixed to the stationary member, and the seal members are movable in the axial direction with respect to the mounting members. A shaft seal mechanism characterized by that. 5. The shaft seal mechanism according to claim 4, wherein each of the mounting members is fastened and fixed by a bolt having a head that faces the stationary member while passing through the intermediate mounting member in the radial direction. .   The shaft seal mechanism according to claim 4, wherein each of the mounting members is fastened and fixed by a bolt that penetrates the intermediate mounting member in the axial direction. Each of the mounting members has an axial auxiliary projection formed on the outer peripheral surface along the circumferential direction and fitted in an intermediate auxiliary groove formed on the bottom of the intermediate mounting groove along the circumferential direction. The shaft seal mechanism according to claim 4, wherein the shaft seal mechanism is fixed.

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