JP2009191815A - Joint structure for marine main engine turbine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure capable of enhancing durability against fretting on a contact section in a joint section of a marine main engine turbine. <P>SOLUTION: In the joint structure 27 of a turbine joint 1 for connecting a turbine rotor shaft 53 and a reduction gear pinion shaft 71 in the marine main engine turbine, piled-up metals 23, 24 having designated thickness and made of cobalt base alloy are provided on the surface of the contact section 18 between the joint shaft 5 of the turbine joint 1 and the turbine rotor shaft 53. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure of a joint portion in a marine main engine turbine.

  Conventionally, a steam turbine is employed as a marine main engine. For example, in the case of an LNG carrier, a steam turbine that burns a boil-off gas (Boil Off Gas) generated from a gas carried during voyage in a boiler and is driven by the steam of the boiler is the main engine (this specification and claims). In the document of the range, it is adopted as "main engine turbine").

  Such a marine main engine turbine employs a turbine joint for power transmission between a turbine rotor shaft of a steam turbine and a pinion shaft of a speed reducer that drives a propeller shaft. This turbine joint is also a flexible joint that absorbs misalignment and the like between the turbine rotor shaft and the reduction gear pinion shaft.

  FIG. 6 is an overall view schematically showing a conventional marine main engine turbine and a turbine joint. In this figure, the main turbine is shown in a longitudinal section. The right side shown is the bow side, and the left side is the stern side. The description of the configuration of the speed reducer, propeller shaft, etc. provided on the stern side is omitted. In the specification and claims, the turbine rotor shaft 53 side that is the input side of the turbine joint is referred to as the upstream side, and the reduction gear pinion shaft 71 side that is the output side is referred to as the downstream side.

  As shown in the figure, the main turbine 51 is provided with a plurality of stages of turbine blades 52, and a turbine rotor shaft 53 rotated by these turbine blades 52 is supported by a bearing 59. The turbine rotor shaft 53 is provided with a connection flange 54 on the stern side. A turbine joint 61 is provided between the turbine rotor shaft 53 and the reduction gear pinion shaft 71, and the connection flange 54 is connected to a spline flange 62 on the upstream side of the turbine joint 61 by a bolt 63. The downstream side of the turbine joint 61 is connected to the connection flange 72 of the reduction gear pinion shaft 71 by a bolt 63. The main engine turbine 51 and the turbine joint 61 are covered with covers 55, 56, and 64 during operation, and these covers 55, 56, and 64 are removed and subjected to disassembly and inspection during maintenance and inspection. Detailed description of the main engine turbine 51 is omitted.

  7 is a longitudinal sectional view of a joint structure in the marine main engine turbine of the VII part shown in FIG. 6, and FIG. 8 is an enlarged view of the VIII part shown in FIG. As shown in FIG. 7, an outer spline 66 is formed on the inner periphery of the spline flange 62, and an inner spline 67 that engages with the outer spline 66 is formed at the end of the joint shaft 65 of the turbine joint 61. Is formed. The outer spline 66 and the inner spline 67 constitute a spline portion 68. The spline portion 68 allows the joint shaft 65 to transmit circumferential rotational power in a state where axial sliding is permitted. ing. The spline portion 68 absorbs thermal expansion or the like in the turbine rotor shaft 53 or the reduction gear pinion shaft 71 by the turbine joint 61 portion.

  As shown in FIG. 8, the contact portion 57 between the turbine joint 61 and the turbine rotor shaft 53 is provided with an upstream contact piece 69 at the shaft core position of the joint shaft 65, and at the shaft core position on the turbine rotor shaft 53 side. The provided center plug 58 and the upstream contact piece 69 come into contact with each other. The surface of the upstream contact piece 69 is formed into a spherical surface, and the surface of the central plug 58 is formed into a flat surface, which are in contact by point contact. Generally, the surface of the contact portion 57 between the upstream contact piece 69 and the central plug 58 is subjected to treatment such as quenching and tempering to increase the surface hardness.

  As a conventional technology related to this type of steam turbine, a turbine blade that can be used stably for a long period of time is obtained by depositing a cobalt-based alloy welding material on the contact surface of the turbine blade with the shroud cover. There exists a thing which intends to provide the provided steam turbine (for example, refer patent document 1).

As another conventional technique, as a surface treatment of a steam turbine member, there is a technique in which high-hardness ceramic powder is build-up welded together with a metal binder (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 11-336502 JP-A-4-224207

  By the way, the main turbine 51 as described above is regularly inspected every several years, and each part is inspected at the time of the periodic inspection. As described above, since both ends of the turbine joint 61 are in contact with the turbine rotor shaft 53 on the upstream side and are in contact with the speed reducer pinion shaft 71 on the downstream side, both rotate to transmit power. It is a structure which does not produce a slip etc. in the contact part.

  However, in the case of a ship turbine joint 61, a slight slip may occur in a contact portion with the turbine rotor shaft 53 due to a hull motion or the like, and fretting (a kind of corrosion wear) may occur in the contact portion due to use over time. When wear due to this fretting occurs, the worn wear powder further promotes wear, and point contact by the spherical surface of the upstream contact piece 69 becomes surface contact, and resistance at the contact portion is increased. In addition, when wear progresses, the turbine joint 61 may bend due to contact on a large surface and lose the function of the joint.

  Therefore, the contact portions of both ends of the turbine joint 61 are also inspected at the time of periodic inspection of the steam turbine, but in order to inspect both ends of the turbine joint 61, many components of the main turbine 51 must be disassembled. It takes a great deal of time and labor to disassemble and move components on the main turbine 51 side that are heavy (for example, several tons). In particular, in order to disassemble the turbine rotor shaft 53, the bearing 59 must be disassembled, and more time and labor are required.

  Further, as described above, the upstream contact piece 69 which is the contact portion 57 between the joint shaft 65 of the turbine joint 61 and the turbine rotor shaft 53 and the surface of the central plug 58 are subjected to surface treatment such as quenching and tempering. Although the hardness is high, wear due to fretting is often found during the regular inspection. In addition, depending on the ship, wear due to fretting may be found at every periodic inspection (for example, every 2.5 years). This wear is considered to be due to the wear powder further worn out as described above.

  If wear due to fretting is found, as described above, the work such as disassembly, replacement, and assembly must be performed with much time and labor, and much time is required for maintenance and inspection work. It takes effort. Therefore, a joint structure that can prevent wear due to fretting of contact portions at both ends of the turbine joint for a long period of time is desired.

  Note that the inventions described in Patent Documents 1 and 2 are intended to prevent wear of the turbine blades, and cannot prevent fretting of the contact portion in the joint of the marine main engine turbine as in the present invention.

  Then, an object of this invention is to provide the joint structure which can raise the durability with respect to the fretting etc. in a contact part in the joint part in the main engine turbines for ships.

  In order to achieve the above object, the present invention provides a joint structure of a turbine joint for connecting a turbine rotor shaft and a reducer pinion shaft in a marine main engine turbine, wherein the joint shaft of the turbine joint, the turbine rotor shaft, Each of the contact portions is provided with a deposit of a cobalt-based alloy having a predetermined thickness. “Cobalt-based alloy deposit” in the specification and claims refers to, for example, deposit such as overlay welding using a welding material of Stellite (R). As a result, since the deposit of the cobalt-based alloy comes into contact with the contact portion between the turbine rotor shaft and the joint shaft, the durability against wear progress due to fretting or the like of these contact portions can be greatly increased, and at the time of maintenance inspection The time and labor required for maintenance and inspection can be greatly reduced by extending the period for parts replacement.

  The contact portion has a center plug whose surface is removable at the axial center position of the turbine rotor shaft end portion, and a spherical surface whose surface protrudes at the axial center position of the joint shaft end portion of the contact portion. A removable contact piece may be provided, and the metal plate may be provided on the surface of the contact portion between the contact piece and the central plug. As a result, the durability of the contact area can be greatly increased, and the wear of the contact area can be restored by replacing the central plug and contact piece during maintenance inspection. Can be reduced, and efficient work can be performed. For example, in the case of a ship that enters the dock for periodic inspection (maintenance inspection) once every 2.5 years as described above, the center plug and the contact piece are removed once every five years. Therefore, the time required for one replacement can be reduced by about 200 hours.

  In addition, a spherical portion whose center projects from the end portion of the joint shaft may be provided, and a deposit having a thickness equal to the axial height of the spherical portion may be provided on the spherical portion. Thereby, the contact between the end of the joint shaft formed by the spherical surface portion and the turbine rotor shaft can be in a substantially point contact state for a long time, and the frictional resistance at the contact portion can be minimized.

  Furthermore, the fill provided in the contact portion of the turbine rotor shaft may have a thickness equal to the thickness of the fill provided in the spherical portion of the joint shaft. Thereby, the amount of progress of wear at the contact portion between the turbine rotor shaft and the joint shaft can be made equal, and the life at the contact portion between the turbine rotor shaft and the joint shaft can be made equivalent.

  Further, an urging portion is provided between the turbine joint and the speed reducer pinion shaft so as to contact the speed reducer pinion shaft and urge the joint shaft toward the turbine rotor shaft side. You may comprise the contact member which contacts a reduction gear pinion shaft, and the urging member which urges | biases this contact member to the reduction gear pinion shaft side from the coupling shaft side. As a result, the joint shaft can be urged to the turbine rotor shaft side with a predetermined force, and the contact pressure at the contact portion between the turbine rotor shaft and the joint shaft is set to a pressure suitable for driving power, etc., by sliding at the contact portion. Wear can be suppressed.

  Furthermore, the surface of the contact portion between the contact member and the speed reducer pinion shaft may be provided with a deposit of a cobalt-based alloy having a predetermined thickness. Thereby, also in the contact part of a joint axis | shaft and a reduction gear pinion axis | shaft, the durability with respect to wear progress by fretting etc. can be improved significantly.

  According to the present invention, by means such as described above, the durability against the progress of wear of the contact portion in the turbine joint of the marine main engine turbine can be greatly increased, and the maintenance inspection of the marine main engine turbine can be performed by extending the part replacement period and the like. The labor and time required for the work can be greatly reduced.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view showing a joint structure of a marine main engine turbine according to an embodiment of the present invention, FIG. 2 is an enlarged view of a portion II shown in FIG. 1, and FIG. 3 is an upstream side shown in FIG. It is the enlarged view which decomposed | disassembled the contact piece and the center plug. In addition, the same code | symbol as the code | symbol mentioned above is attached | subjected and demonstrated to the same structure regarding the turbine rotor shaft 53 and the reduction gear pinion shaft 71 shown in FIGS. In these figures, the circular shaft is shown as a half section.

  As shown in FIG. 1, the turbine joint 1 is provided in a state in which a turbine rotor shaft 53 is connected to the upstream side and a reduction gear pinion shaft 71 is connected to the downstream side. The spline flange 2 connected to the connection flange 54 of the turbine rotor shaft 53 is provided on the upstream side of the turbine joint 1, and the spline flange 3 connected to the connection flange 72 of the reduction gear pinion shaft 71 on the downstream side. Is provided. These spline flanges 2 and 3 are connected to both connection flanges 54 and 72 by bolts 4.

  Further, an inner spline 7 that engages with an outer spline 6 formed on the inner periphery of the spline flange 2 is formed on the upstream side of the joint shaft 5 of the turbine joint 1, and the inner side of the spline flange 3 is formed on the downstream side. An inner spline 7 that engages with the outer spline 6 formed on the circumference is formed. The joint shaft 5, the turbine rotor shaft 53, and the reduction gear pinion shaft 71 are engaged with each other by the spline portion 8 including the outer spline 6 and the inner spline 7. Thereby, rotational power is transmitted while allowing the spline portion 8 to allow the joint shaft 5 to slide in the axial direction. The spline flanges 2 and 3 are respectively provided with locking claws 9 for locking the axial movement of the inner spline 7 at a predetermined position.

  Further, the joint shaft 5 is formed such that the axial length is shorter than the interval L between the turbine rotor shaft 53 and the reduction gear pinion shaft 71, and the joint shaft 5 is provided between the turbine rotor shaft 53 and the reduction gear pinion shaft 71. Is provided with a predetermined gap S. An upstream contact piece 10 is provided at the axial center position on the upstream side of the joint shaft 5, and the upstream contact piece 10 is in contact with the central plug 20 provided at the axial position of the turbine rotor shaft 53. . Details of the center plug 20 will be described later. The upstream contact piece 10 is provided in an insertion hole 11 formed at the axial center position of the joint shaft 5.

  On the other hand, on the downstream side of the joint shaft 5, a downstream contact piece 12 is provided at the axial center position, and the downstream contact piece 12 is in contact with the speed reducer pinion shaft 71. The downstream contact piece 12 is provided so as to be slidable in the axial direction within the slide hole 14 of the guide member 13 provided at the downstream end of the joint shaft 5. The downstream contact piece 12 is formed in a cylindrical shape with the joint shaft 5 side opened and the speed reducer pinion shaft 71 side closed. Between the downstream contact piece 12 and the guide member 13, a spring 15 is provided as a biasing member that biases the downstream contact piece 12 toward the reduction gear pinion shaft 71. By urging the downstream contact piece 12 toward the reduction gear pinion shaft 71 by the spring 15, the joint shaft 5 is urged toward the turbine rotor shaft 53 via the guide member 13 by the reaction force. The upstream contact piece 10 provided at the upstream axial center position is pressed against the center plug 20 of the turbine rotor shaft 53. A portion including the downstream contact piece 12 and the spring 15 is provided between the reduction gear pinion shaft 71 and the joint shaft 5, and an urging portion that urges the joint shaft 5 toward the turbine rotor shaft 53 side. 16. Thus, by urging the joint shaft 5 toward the turbine rotor shaft 53, the joint shaft 5 is prevented from easily moving in the axial direction during power transmission. The biasing force of the joint shaft 5 is set by the spring force of the spring 15.

  Based on FIG. 2, the contact part 18 in the upstream of the joint axis | shaft 5 is demonstrated in detail. An insertion hole 19 is provided at the axial center position of the turbine rotor shaft 53, and a central plug 20 is provided in the insertion hole 19. The center plug 20 is fixed in the insertion hole 19 by shrink fitting or the like. The downstream end surface of the center plug 20 is provided so as to be substantially flush with the downstream end surface of the turbine rotor shaft 53.

  On the other hand, the upstream contact piece 10 provided at the axial center position of the joint shaft 5 includes a large-diameter base portion 21 inserted into the insertion hole 11 provided in the joint shaft 5, and a turbine rotor from the center portion of the base portion 21. It has the protrusion part 22 which protrudes in the axis | shaft 53 side. The base 21 inserted into the insertion hole 11 is flush with the upstream end surface of the joint shaft 5 on the turbine rotor shaft 53 side, and is fixed in the insertion hole 11 by shrink fitting or the like. Moreover, the protrusion part 22 is formed with the substantially same outer diameter as the said center plug 20, and protrudes in the center plug 20 side by predetermined height. The surface of the upstream contact piece 10 is formed into a spherical surface, the surface of the central plug 20 is formed into a flat surface, and these contact portions 18 are point contacts.

  Further, cobalt metal alloy deposits 23 and 24 are provided at the contact portions 18 between the central plug 20 on the turbine rotor shaft 53 side and the upstream contact piece 10 on the joint shaft 5 side, respectively. The cobalt-based alloy deposits 23 and 24 are made of, for example, stellite (R), and are formed by overlay welding using the welding material. The deposits 23 and 24 are formed in a predetermined circle around the axis. In this way, the contact portion 18 provided with the deposits 23 and 24 of the cobalt base alloy has a structure in which the deposits 23 and 24 of the cobalt base alloy having very high wear resistance are in contact with each other.

  As shown in FIG. 3, in this embodiment, the cobalt-base alloy-based deposits 23, 24 are arranged so that the axial height h (axis) of the spherical portion 25 formed on the protruding portion 22 of the upstream contact piece 10. And a thickness t substantially equal to the direction dimension). By setting the deposits 23 and 24 to such a thickness t, the deposit 24 in the upstream contact piece 10 of the joint shaft 5 and the deposit 23 in the center plug 20 of the turbine rotor shaft 53 are equally worn. Thus, the contact by the deposits 23 and 24 of the cobalt base alloy can be maintained until the wear amount is such that the upstream contact piece 10 and the central plug 20 are in surface contact. In this embodiment, both the metal plates 23 and 24 have a thickness t. However, by setting at least the metal plate 24 to a thickness t, it is possible to effectively wear the spherical surface portion 25 and make surface contact. Can be deterred. In this case, the deposit 23 on the side of the center plug 20 becomes thicker.

  Further, in this embodiment, cobalt base alloy-based metal deposits 23 and 24 are provided in the contact portion 18 between the upstream contact piece 10 on the upstream side of the joint shaft 5 and the central plug 20 of the turbine rotor shaft 53. Although the example has been described, the contact portion between the downstream contact piece 12 and the reduction gear pinion shaft 71 on the downstream side of the joint shaft 5 may be provided with a deposit based on a cobalt-based alloy. Accordingly, it may be appropriately adopted and is not limited to the above embodiment.

  FIG. 4 is a schematic diagram showing a test apparatus for confirming the effect of the joint structure according to the present invention, and FIG. 5 is a graph showing a test result by the test apparatus shown in FIG. In the test apparatus 31 shown in FIG. 4, a moving body 34 holding a lower test piece 33 is supported on an upper portion of a pedestal 32 by an elastic member 35 such as a spring, and the upper test piece 36 can be moved up and down on the moving body 34. A holding body 37 is provided for holding. An arm 40 is provided on the upper portion of the holding body 37. One end (the left end in the drawing) is swingably supported by the support block 38 of the pedestal 32 and the other end (the right end in the drawing) is provided with a predetermined weight 39. ing. The holding body 37 is pressed downward by the pressing portion 41 of the arm 40 by the weight 39 provided on the arm 40. By pressing the holding body 37 downward, the upper test piece 36 held by the holding body 37 is pressed against the lower test piece 33 with a predetermined pressing force. The upper test piece 36 is provided with a protrusion 42 facing downward, and the protrusion 42 is pressed against the lower test piece 33. A contact portion between the protrusion 42 and the lower test piece 33 is a wear test portion.

Further, the moving body 34 is provided with an actuating member 43 in the lateral direction, and the actuating member 43 is linearly moved by a cam 44 by driving an electric motor 45 with an eccentric shaft. By moving the actuating member 43 linearly with the amount of eccentricity of the cam 44, the moving body 34 moves the lower test piece 33 horizontally, and at the contact portion with the protrusion 42 of the upper test piece 36 held by the holding body 37. Causes a slip. In this example, the contact portion load is 47 kgf / mm ² , the amplitude for linearly moving the operating member 43 by the cam 44 is 20 μm, and the test time is 2 hours.

  As shown in FIG. 6, the test results by the test apparatus 31 shown in FIG. 5 include surface quenching for the upper test piece 36 and surface annealing for the lower test piece 33 as shown in Test 1. Assuming that the amount of wear in the case of performing "1" is "1", as shown in Test 2, as shown in the turbine joint structure 27 of the present invention, the deposits 23 and 24 of the cobalt-based alloy are connected to the upper test piece 36 and the lower test piece 33. In this case, the generation of wear powder is very small and the wear amount is “about 0.3”. Therefore, it can be said that the turbine joint structure 27 of the present invention exhibits about three times the wear resistance as compared with the prior art. Further, since the generation of wear powder is very small, it can be said that there is no acceleration of wear by the wear powder.

  As described above, according to the turbine joint structure 27, the durability is greatly increased against the progress of wear due to fretting in the contact portion 18 between the upstream contact piece 10 of the joint shaft 5 and the central plug 20 of the turbine rotor shaft 53. Therefore, it is possible to lengthen the replacement period of the upstream contact piece 10 and the central plug 20 in the contact portion 18 with the turbine joint 1 during maintenance and inspection of the main turbine 51 (FIG. 6). Labor and time during inspection can be greatly reduced.

  The cobalt-base alloy deposits 23 and 24 may be of any suitable type depending on the use conditions. For example, even when the above-mentioned stellite (R) is used, the class may be the use conditions, etc. It may be determined according to.

  Furthermore, the above-described embodiment shows an example, and various modifications can be made without departing from the gist of the present invention, and the present invention is not limited to the above-described embodiment.

  The joint structure of a marine main engine turbine according to the present invention has a contact portion that makes contact in the axial direction and can be used for a joint structure that transmits rotational force.

1 is a longitudinal sectional view showing a joint structure of a marine main engine turbine according to an embodiment of the present invention. It is the II section enlarged view shown in FIG. It is the enlarged view which decomposed | disassembled the upstream contact piece and center plug shown in FIG. It is a schematic diagram which shows the test apparatus for confirming the effect of the joint structure which concerns on this invention. It is a graph which shows the test result by the testing apparatus shown in FIG. It is a general view which shows the conventional marine main engine turbine and a turbine coupling typically. It is a longitudinal cross-sectional view of the joint structure in the marine main engine turbine of the VII part shown in FIG. It is the VIII section enlarged view shown in FIG.

Explanation of symbols

1 ... Turbine joint
5 ... Joint shaft
DESCRIPTION OF SYMBOLS 8 ... Spline part 10 ... Upstream side contact piece 12 ... Downstream side contact piece 13 ... Guide member 15 ... Spring 16 ... Energizing part 18 ... Contact part 20 ... Center plug 22 ... Projection part 23, 24 ... Filling 25 ... Spherical part 27 ... Turbine joint structure
h: Axial height
t ... thickness

Claims (6)

A joint structure of a turbine joint for connecting a turbine rotor shaft and a reduction gear pinion shaft in a marine main engine turbine,
A joint structure for a marine main engine turbine, wherein a surface of a contact portion between the joint shaft of the turbine joint and the turbine rotor shaft is provided with a deposit of a cobalt-based alloy having a predetermined thickness. At the axial center position of the turbine rotor shaft end portion of the contact portion, there is a removable central plug having a flat surface.
At the axial center position of the joint shaft end portion of the contact portion, a spherically removable contact piece whose surface protrudes,
The marine main engine turbine joint structure according to claim 1, wherein the metal plate is provided on a surface of a contact portion between the contact piece and the central plug.   3. The marine main engine according to claim 1, wherein a spherical portion projecting from the center is provided at an end portion of the joint shaft, and the metal portion having a thickness equal to the axial height of the spherical portion is provided on the spherical portion. Turbine joint structure.   The joint structure for a marine main engine turbine according to claim 3, wherein the filling provided in the contact portion of the turbine rotor shaft has a thickness equal to the thickness of the filling provided in the spherical portion of the joint shaft. Between the turbine joint and the reduction gear pinion shaft, provided with a biasing portion that contacts the reduction gear pinion shaft and biases the joint shaft toward the turbine rotor shaft side,
The biasing portion includes a contact member that contacts the reduction gear pinion shaft, and a biasing member that biases the contact member from the joint shaft side to the reduction gear pinion shaft side. A joint structure for a marine main engine turbine according to any one of the preceding claims.   The joint structure of a marine main engine turbine according to claim 5, wherein a surface of a contact portion between the contact member and the reduction gear pinion shaft is provided with a deposit of a cobalt-based alloy having a predetermined thickness.

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