JP2005003199A - Shaft seal mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the production cost and downsize the shaft seal mechanism. <P>SOLUTION: Beside a group of annular thin plates is installed by arranging two or more thin plates in an annular space between a rotor and a stator and the outer circumference base ends of these thin plates are fixed to the above stator side, the shaft seal mechanism divides the annular space between the above rotor and the above stator into the high pressure side range and the low pressure side range with the above annular thin plate group, by making the inner circumference end sides of these thin plates unfixed to the circumference face of the above rotor. The outer circumference base end of each thin plate as above is constituted so as to be inserted and fixed between one pair of flexible rings to retain the thin plate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shaft seal mechanism suitable for use in a rotating shaft of a large fluid machine such as a gas turbine, a steam turbine, a compressor, a water turbine, a refrigerator, and a pump.

  In general, a shaft seal mechanism for reducing the amount of leakage of working fluid flowing from the high pressure side to the low pressure side is provided around the rotation shaft of the gas turbine or the steam turbine. As an example of this shaft seal mechanism, for example, a leaf seal shown in Patent Document 1 below is known.

  An example of this type of conventional leaf seal is shown in FIG. The leaf seal 1 shown in FIG. 1 has an annular shape in which flat thin plates 3 having a predetermined plate width dimension in the axial direction of the rotary shaft 2 are arranged in multiple layers in the circumferential direction of the rotary shaft 2 with a small interval. The thin plate group 9 is configured. These thin plates 3 are fixed to the leaf seal ring 5 at the outer peripheral base end via a brazing portion 4 and the inner peripheral front end is acutely angled with a predetermined preload with a circumferential inclination with respect to the peripheral surface of the rotary shaft 2. It is in sliding contact. These thin plates 3 have a T-shape when viewed from the opposite side, and the width dimension w1 on the outer peripheral proximal end side is wider than the width dimension w2 on the inner peripheral distal end side.

  These thin plates 3 seal the outer periphery of the rotary shaft 2 to divide the annular space around the rotary shaft 2 into a high pressure side region and a low pressure side region. The leaf seal ring 5 has a high pressure side plate 7 on the side facing the high pressure side region with the thin plates 3 interposed therebetween, and a low pressure side plate 8 on the side facing the low pressure side region, respectively. It is arranged as a guide plate.

  In the leaf seal 1 configured as described above, when the rotary shaft 2 rotates, the tip of each thin plate 3 floats from the peripheral surface of the rotary shaft 2 due to the dynamic pressure effect generated by the rotation of the rotary shaft 2, and Contact between the tip and the rotating shaft 2 is avoided. Thereby, abrasion of each thin plate 3 is prevented and the seal life is extended.

JP 2002-13647 A

  By the way, the conventional leaf seal 1 is manufactured by sandwiching each thin plate 3 between two divided housings 5a and 5b and then welding or bolting the joints between the housings 5a and 5b. However, the overall diameter differs depending on the installation location. Therefore, in the manufacture of the housings 5a and 5b, it is necessary to prepare dedicated jigs individually according to the diameters thereof. Since the leaf seal 1 is used in various places and most of them have different diameters, a large number of dedicated jigs are required, which hinders the reduction of the manufacturing cost.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide means capable of reducing the manufacturing cost of the shaft seal mechanism and contributing to downsizing.

  The present invention employs the following means in order to solve the above problems.

  That is, in the shaft seal mechanism according to claim 1 of the present invention, a plurality of thin plates are arranged in an annular space between the rotor and the stator, and an annular thin plate group is disposed, and the outer peripheral proximal end side of these thin plates is arranged. While fixing to the stator side, the inner peripheral front end side of these thin plates is not fixed to the peripheral surface of the rotor, so that the annular space between the rotor and the stator is high-pressure in the annular thin plate group. The shaft seal mechanism is divided into a side region and a low pressure side region, and the outer peripheral proximal end side of each thin plate is sandwiched and fixed between a pair of thin plate holding rings having flexibility.

  According to the shaft seal mechanism of the first aspect, the curvature can be freely changed according to the curvature of the recessed groove to be installed. In addition, since the thickness of each thin plate retaining ring has been thinned to such an extent that flexibility can be exhibited, the outer dimensions of these thin plate retaining rings can be reduced, which can contribute to the compactness of the entire shaft seal mechanism. It has become.

  The shaft seal mechanism according to claim 2 is the shaft seal mechanism according to claim 1, wherein the outer peripheral proximal end side of each thin plate is between the thin plate holding rings and the relative movement of the thin plates with respect to the thin plate holding rings. It is characterized by being sandwiched and fixed via a displacement prevention member that regulates the above.

  According to the shaft seal mechanism of the second aspect, by providing the shift prevention member, it is possible to effectively prevent the shift of each thin plate. That is, rattling of each thin plate with respect to each thin plate holding ring can be prevented.

  According to a third aspect of the present invention, in the shaft sealing mechanism according to the first or second aspect, the thin plate group in which a notch is formed on the side edge in the axial direction can be fitted into the notch. A shaft sealing mechanism provided with a plate provided with a stepped portion on a side surface, wherein the plate has a stepped portion of the plate corresponding to a notch of the thin plate group from the rotor axial direction with respect to the thin plate group. Are arranged in contact with each other, and the thin plate group and the plate are sandwiched and fixed by the thin plate holding rings.

  According to the shaft seal mechanism of the third aspect, the plate can be easily attached.

  According to a fourth aspect of the present invention, in the shaft seal mechanism, a plurality of thin plates are arranged in an annular space between the rotor and the stator to arrange an annular thin plate group, and the outer peripheral proximal end side of these thin plates is fixed to the stator side. In addition, the inner peripheral front end side of these thin plates is not fixed to the peripheral surface of the rotor, so that the annular space between the rotor and the stator in the annular thin plate group is a high pressure side region and a low pressure side. A shaft seal mechanism that divides into regions, and each thin plate is bent along the peripheral surface of the annular space after the respective proximal end sides of the outer periphery are welded and fixed to each other in a state of being overlapped with each other. It is characterized by being.

  According to the shaft seal mechanism of the fourth aspect, the curvature can be freely changed according to the curvature of the recessed groove to be installed.

  Furthermore, in the shaft seal mechanism according to claim 5, a plurality of thin plates are arranged in an annular space between the rotor and the stator to dispose an annular thin plate group, and the outer peripheral base end side of these thin plates is disposed on the stator. And the inner circumferential front end side of these thin plates is not fixed to the circumferential surface of the rotor, so that the annular space between the rotor and the stator in the annular thin plate group is a high-pressure side region. And a shaft seal mechanism that forms a leaf seal that divides into a low-pressure side region, and the outer peripheral base end side of each thin plate forming a flexible thin plate group as a whole is sandwiched between a pair of flexible thin plate holding rings. It is characterized by being fixed.

  According to a sixth aspect of the present invention, in the shaft seal mechanism, a plurality of thin plates are arranged in an annular space between the rotor and the stator to arrange an annular thin plate group, and the outer peripheral proximal end side of these thin plates is fixed to the stator side. In addition, the inner peripheral front end side of these thin plates is not fixed to the peripheral surface of the rotor, so that the annular space between the rotor and the stator in the annular thin plate group is a high pressure side region and a low pressure side. A shaft seal mechanism that forms a leaf seal that divides into regions, and in the state where the thin plates are overlapped, the outer peripheral proximal end sides are welded and fixed to each other between adjacent ones, and a flexible thin plate group as a whole. Then, it is curved along the peripheral surface of the annular space.

  According to the shaft seal mechanism of any one of claims 1 to 6 of the present invention, since the curvature can be freely changed according to the installation location, the conventional special treatment as in the prior art. There is no need to prepare the ingredients individually. As a result, the manufacturing cost of the shaft seal mechanism can be reduced. In addition, since the thickness of each thin plate retaining ring has been thinned to such an extent that flexibility can be exhibited, the outer dimensions of these thin plate retaining rings can be reduced, and it is possible to contribute to the compactness of the shaft seal mechanism as a whole. It has become.

  In addition, according to the shaft seal mechanism of the second aspect, it is possible to prevent the thin plates from rattling with respect to the thin plate holding rings.

  Further, according to the shaft seal mechanism of the third aspect, the plate can be easily attached.

  Further, according to the shaft seal mechanism of the fourth aspect, the same effect as that of the shaft seal mechanism of the first aspect can be obtained.

  According to the shaft seal mechanisms of the fifth and sixth aspects of the present invention, the effects described in the embodiments can be obtained in the same manner as the inventions of the respective claims.

  One embodiment of the present invention will be described below with reference to the drawings, but the present invention should not be construed as being limited thereto. In the present embodiment, the case where the large fluid machine to which the present invention is applied is a gas turbine turbine will be described as an example. However, a steam turbine, a compressor, a water turbine, a refrigerator, a pump, and an aircraft gas turbine engine are described. It can be applied to the rotating shaft of other large fluid machines.

  First, FIG. 1 shows a schematic configuration of a gas turbine. In the figure, reference numeral 20 denotes a compressor, reference numeral 21 denotes a combustor, and reference numeral 22 denotes a turbine. The compressor 20 takes in a large amount of air and compresses it. Usually, in a gas turbine, a part of the power obtained by a rotary shaft 23 described later is used as power for the compressor. The combustor 21 mixes fuel with the air compressed by the compressor 20 and burns it. The turbine 22 introduces and expands the combustion gas generated in the combustor 21 and blows it to the rotor blades 23e provided on the rotating shaft 23 to convert the thermal energy of the combustion gas into mechanical rotational energy. Thus, power is generated.

  The turbine 22 is provided with a plurality of stationary blades 24a arranged on the stator 24 side in addition to the plurality of moving blades 23e arranged on the rotating shaft 23 side. The rotating shafts 23 are alternately arranged in the axial direction. Each rotor blade 23e receives the pressure of the combustion gas flowing in the axial direction of the rotating shaft 23 to rotate the rotating shaft 23, and the rotational energy given to the rotating shaft 23 is extracted from the shaft end and used. Yes. A leaf seal 25 is provided between each stationary blade 24a and the rotating shaft 23 as a shaft seal mechanism for reducing the amount of combustion gas leaking from the high pressure side to the low pressure side.

  FIG. 2 shows an enlarged sectional view of the leaf seal 25. In the figure, the leaf seal 25 is seen in a cross section including the axis of the rotary shaft 23. In the following description, the basic configuration of the leaf seal 25 will be described first, and then this feature point will be described.

  First, the basic configuration of the leaf seal 25 will be described. As shown in FIG. 2, the leaf seal 25 is arranged in the annular space between the rotating shaft 23 and the stator 24 so that the plate width directions are aligned in the axial direction of the rotating shaft 23 and in the circumferential direction of the rotating shaft 23. An annular thin plate group 29 </ b> A in which a large number of thin plates 29 are arranged in multiple positions with a minute interval therebetween is provided.

  Each thin plate 29 is fixed to the stator 24 on the outer peripheral proximal end side, and is disposed at an acute angle with a circumferential inclination with respect to the peripheral surface 23a of the rotating shaft 23 on the inner peripheral distal end side. In this way, the annular thin plate group 29A composed of the thin plates 29 divides the annular space between the rotating shaft 23 and the stator 24 into a high pressure side region and a low pressure side region.

  Next, the characteristic points of the leaf seal 25 having the above basic configuration will be described below with reference to FIG.

  As shown in the figure, the leaf seal 25 of the present embodiment has a substantially T-shape in which the plate width is wider on the outer peripheral proximal end side than on the inner peripheral distal end side, and a plurality of the multiple overlaps are provided. A thin plate 29, a pair of leaf seal retainers 51 and 52 (thin plate retaining rings) that sandwich the thin plates 29 in an annular state, one side edge of each thin plate 29 that faces the high pressure side region, and one leaf seal retainer 51. Between the thin plate 29 and the other side edge of the thin plate 29 facing the low pressure side region and the other thin plate holding ring 52. And an annular low-pressure side plate 54 that comes into contact with each other side edge, and a spacer 55 that is sandwiched between the leaf seal retainers 51 and 52 to reduce the shakiness of each thin plate 29 against them. .

  Each thin plate 29 is a substantially T-shaped thin steel plate having flexibility, and notches 29a are formed on both side edges. The thin plates 29 are welded and fixed to each other on the base end side of the outer periphery (the welded portions will be described later in the description of FIG. 4), forming a flexible thin plate group as a whole.

  The high-pressure side plate 53 is an annular thin plate, and has an outer peripheral portion that is one step thicker than the inner peripheral portion so that one side surface is stepped when viewed in a cross section including the axis of the rotating shaft 23. ing. Similarly, the low-pressure side plate 54 is also an annular thin plate, and has an outer peripheral portion that is one step thicker than the inner peripheral portion so that one side surface thereof is stepped when viewed in the cross section. Then, after the high-pressure side plate 53 and the low-pressure side plate 54 are overlapped on both side surfaces of each thin plate 29 so as to be fitted into the notches 29a in the stepped portions, the leaf seal retainers 51, It is fixed by being sandwiched between 52.

  The leaf seal retainers 51 and 52 are metal parts having flexibility that are generally “U” -shaped when viewed in a cross section including the axis of the rotary shaft 23, and are formed when they are overlapped with each other. The wide portions of the thin plates 29 and the spacers 55 are fitted into the recesses 51a and 52a.

  As shown in FIG. 3, the spacer 55 is a leaf spring formed with a plurality of convex portions 55a that generate an urging force by being elastically deformed when pressed, and as shown in FIG. An urging force that presses the annular thin plate group 29A from the outer peripheral side is applied to the concave grooves 51a and 52a so that the annular thin plate group 29A does not rattle in the 51a and 52a. And the relative position between these can be fixed by welding between the upper surface of this spacer 55, and each leaf seal retainer 51 and 52 in the welding location y4.

  A method for manufacturing the leaf seal 25 having the above-described configuration will be described below with reference to FIGS. The leaf seal 25 is manufactured through a thin plate welding process, a bending process, and a ring mounting process.

  First, in the thin plate welding step, as shown in FIG. 4 (a), the thin plate 29 obtained by punching steel plates into a T shape is overlapped and obliquely overlapped, and then the outer peripheral base end side is welded. That is, as shown in FIG. 5B, the thin plates 29 are welded to each other at the outer peripheral end and the both side ends on the outer peripheral base end side (reference numerals y1 to y3).

  In the subsequent bending step, rough bending is applied in advance to both the thin plates 29 welded to each other and the leaf seal retainers 51 and 52 before the next shaft seal mechanism insertion step. FIG. 5C shows each thin plate 29 after the bending process.

  In the subsequent ring mounting step, as shown in FIG. 5, the outer peripheral proximal end side, the high pressure side plate 53, the low pressure side plate 54, and the spacer 55 of each welded thin plate 29 are sandwiched between the leaf seal retainers 51 and 52. Thereafter, the space between the leaf seal retainers 51 and 52 is fixed.

  That is, the annular high-pressure side plate 53 that contacts the one side edge is sandwiched and fixed between the one side edge of each thin plate 29 facing the high-pressure side region and the one leaf seal retainer 51. Similarly, an annular low-pressure side plate 54 in contact with each other side edge is sandwiched and fixed between the other side edge of each thin plate 29 facing the low-pressure side region and the other leaf seal retainer 52. Furthermore, a spacer 55 that restricts the relative movement of each thin plate 29 with respect to the outer peripheral proximal end side of each thin plate 29 and each leaf seal retainer 51, 52 is sandwiched and fixed.

  Thus, each leaf seal retainer 51, 52 after sandwiching each component is welded and fixed to the spacer 55 at each welding location y4 (see FIG. 2). As a result, the leaf seal retainers 51 and 52 are fixed.

  According to the structure and manufacturing method of the leaf seal 25 described above, even if the place where the leaf seal 25 is installed and the size of the diameter are slightly different, it is not necessary to prepare a dedicated jig individually as in the prior art. The manufacturing cost of the leaf seal 25 can be reduced. Further, since the thickness of each leaf seal retainer 51, 52 is thinned to such an extent that flexibility can be exhibited, the outer dimensions of these leaf seal retainers 51, 52 can be reduced, and the leaf seal 25 as a whole can be made compact. It is also possible to contribute.

  When the assembled shaft seal member (leaf seal 25) is assembled in the stator 24, the shaft seal member (leaf seal 25) may be inserted while being bent along the curvature of the concave groove 71 provided on the inner peripheral surface side of the stator 24. According to this, since the curvature of the leaf seal 25 can be freely changed according to the installation location, it is not necessary to separately prepare a dedicated jig as in the prior art. Thereby, the manufacturing cost of the leaf seal 25 can be reduced.

  The leaf seal manufacturing method of the present embodiment employs a method in which the high-pressure side plate 53 is sandwiched and fixed between one side edge of each thin plate 29 and one thin plate holding ring 51 in the ring mounting step. According to this method, the high-pressure side plate 53 can be easily attached, so that the manufacturing cost can be further reduced.

  The leaf seal manufacturing method of the present embodiment employs a method in which the low-pressure side plate 54 is sandwiched and fixed between the other side edge of each thin plate 29 and the thin plate holding ring 52 in the ring mounting step. According to this method, the low-pressure side plate 54 can be easily attached, so that the manufacturing cost can be further reduced.

It is a schematic structure sectional view showing one embodiment of a gas turbine provided with a leaf seal (shaft seal mechanism) concerning the present invention. It is a figure which shows the incorporating structure with respect to the stator of the leaf seal, Comprising: It is sectional drawing seen from the cross section containing the axis line of a rotating shaft. It is a perspective view which shows the spacer with which the leaf seal is equipped. It is a figure which shows the manufacturing method of the leaf seal, Comprising: (a) And (b) is a figure which shows the thin plate after a thin plate welding process, (c) is a figure which shows the thin plate after a bending process. It is a figure which shows the continuation of the manufacturing method of the leaf seal, Comprising: It is an assembly drawing for demonstrating a ring attachment process. It is a figure which shows an example of the conventional shaft seal mechanism, Comprising: It is sectional drawing seen from the cross section containing the axis line of a rotating shaft.

Explanation of symbols

23 ... Rotating shaft (rotor)
24 ... Stator 25 ... Leaf seal (shaft seal mechanism)
29 ... thin plate 29A ... annular thin plate group 51, 52 ... leaf seal retainer (thin plate retaining ring)
53 ... High-pressure side plate (plate)
54 ... Low pressure side plate
55 ... Spacer (shift prevention member)

Claims (6)

  A plurality of thin plates are arranged in an annular space between the rotor and the stator to dispose a group of annular thin plates, and the outer peripheral proximal end side of these thin plates is fixed to the stator side, and the inner peripheral distal end side of these thin plates is A shaft seal mechanism that divides the annular space between the rotor and the stator into a high-pressure side region and a low-pressure side region in the annular thin plate group by being non-fixed to the peripheral surface of the rotor, A shaft seal mechanism characterized in that an outer peripheral proximal end side of a thin plate is sandwiched and fixed between a pair of flexible thin plate holding rings.   The outer peripheral base end side of each of the thin plates is sandwiched and fixed between the thin plate holding rings via a slip prevention member that restricts the relative movement of the thin plates with respect to the thin plate holding rings. Item 2. The shaft seal mechanism according to Item 1.   A shaft seal mechanism comprising a thin plate group in which a notch is formed in an axial side edge and a plate having a stepped portion that can be fitted in the notch on a side surface, the notch of the thin plate group The plate is disposed in contact with the thin plate group from the rotor axial direction so that the stepped portion of the plate corresponds to the plate, and the thin plate group and the plate are sandwiched and fixed by the thin plate holding rings. The shaft seal mechanism according to claim 1 or 2, wherein the shaft seal mechanism is provided.   A plurality of thin plates are arranged in an annular space between the rotor and the stator to dispose a group of annular thin plates, and the outer peripheral proximal end side of these thin plates is fixed to the stator side, and the inner peripheral distal end side of these thin plates is A shaft seal mechanism that divides the annular space between the rotor and the stator into a high-pressure side region and a low-pressure side region in the annular thin plate group by being non-fixed to the circumferential surface of the rotor, The shaft sealing mechanism, wherein the thin plate is bent along the peripheral surface of the annular space after the outer peripheral proximal end sides are welded and fixed to each other between adjacent ones in a state where the thin plates are overlapped. .   A plurality of thin plates are arranged in an annular space between the rotor and the stator to dispose a group of annular thin plates, and the outer peripheral proximal end side of these thin plates is fixed to the stator side, and the inner peripheral distal end side of these thin plates is A shaft seal mechanism that forms a leaf seal that divides the annular space between the rotor and the stator into a high-pressure side region and a low-pressure side region in the annular thin plate group by being non-fixed to the peripheral surface of the rotor. A shaft sealing mechanism characterized in that the outer peripheral base end side of each thin plate forming a flexible thin plate group as a whole is sandwiched and fixed between a pair of flexible thin plate holding rings.   A plurality of thin plates are arranged in an annular space between the rotor and the stator to dispose a group of annular thin plates, and the outer peripheral proximal end side of these thin plates is fixed to the stator side, and the inner peripheral distal end side of these thin plates is A shaft seal mechanism that forms a leaf seal that divides the annular space between the rotor and the stator into a high-pressure side region and a low-pressure side region in the annular thin plate group by being non-fixed to the peripheral surface of the rotor. And each thin plate is overlapped with each other in a state where the respective thin base plates are overlapped with each other to form a thin plate group having flexibility as a whole, and then on the circumferential surface of the annular space. A shaft sealing mechanism characterized by being curved along.

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