JP2012010450A - Bearing retaining structure of steam turbine generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing retaining structure of a steam turbine generator capable of completely preventing grease filled in the inside of a bearing from leaking out and scattering by stabilizing behavior of the bearing, and thus extending a service life of the bearing.SOLUTION: An annular resin member 26 having a coefficient of linear expansion larger than that of a generator casing 7 is interposed between the generator casing 7 and bearings 12, 15.

Description

  The present invention relates to a bearing holding structure for a steam turbine generator.

  In general, a steam turbine generator is configured to generate electricity by rotationally driving a turbine using steam energy.

  In recent years, as the steam turbine generator, a small and lightweight generator that can be mounted on an automobile has been developed, and this type of steam turbine generator is made of an aluminum alloy for reducing the weight of the generator casing. The generator casing made of the aluminum alloy has a structure in which the turbine shaft is rotatably supported via a bearing made of bearing steel.

  Note that a small and lightweight steam turbine generator that can be mounted on an automobile as described above is not found in patent documents and non-patent documents, but it shows the general technical level of a power generator using a steam turbine. For example, Patent Document 1 is available.

JP 2009-68367 A

By the way, in the steam turbine generator as described above, the linear expansion coefficient of the aluminum alloy constituting the generator casing is 24 × 10 ⁻⁶ [1 / ° C.], whereas the linear expansion of the bearing steel constituting the bearing is made. The generator casing and the bearing of the steam turbine generator, which has a coefficient of 12.5 × 10 ⁻⁶ [1 / ° C.] and is assembled and manufactured at room temperature (20 [° C.]) The temperature rises to about 80 [° C.].

For this reason, when the steam turbine generator is operated, if the clearance generated between the generator casing and the outer ring of the bearing is c, the outer diameter of the bearing is D = φ17 [mm], and at the time of manufacture and operation When the temperature difference with ΔT is
c = D × ΔT × (24-12.5) × 10 ⁻⁶
= 17 * (80-20) * (24-12.5) * 10 < ^-6 >
= 0.01173 [mm]
≒ 12 [μm]
As described above, there is a problem that the clearance becomes wider, the behavior of the bearing becomes unstable, the grease filled in the bearing leaks and scatters, and the life of the bearing is shortened.

  In addition, the present inventors also considered that the grease could be leaked and considered to fill the bearing with a larger amount of grease. However, when the grease was filled more into the bearing, the friction increased and the heat generation was reversed. The amount increased and the deterioration of the grease was accelerated, which was not a preferable measure.

  In view of such circumstances, the present invention stabilizes the behavior of the bearing, can reliably prevent the grease filled in the bearing from leaking and scattering, and can extend the life of the bearing. A bearing holding structure is to be provided.

According to the present invention, a rotor having a shaft on both sides and a turbine provided on one shaft is rotatably supported by a generator casing via a bearing made of a material having a linear expansion coefficient different from that of the generator casing. A steam turbine generator bearing holding structure,
An annular resin member is provided between the generator casing and the bearing,
The present invention relates to a bearing holding structure for a steam turbine generator, characterized in that the linear expansion coefficient of the annular resin member is larger than the linear expansion coefficient of the generator casing.

  According to the above means, the following operation can be obtained.

  Since an annular resin member having a larger linear expansion coefficient than the generator casing is interposed between the generator casing and the bearing, the generator casing of the steam turbine generator assembled and manufactured at room temperature, and Even if the temperature of the bearing rises due to steam flowing during operation, and the clearance between the generator casing 7 and the outer ring of the bearing expands due to a difference in expansion due to the temperature rise, the annular resin member and the generator casing By expanding sufficiently between the outer ring of the bearing to compensate for the expanded clearance, there is no risk of rattling between the generator casing and the bearing.

  As a result, during the operation of the steam turbine generator, it is possible to avoid the unstable behavior of the bearing as in the prior art, and the vibration is attenuated by the damping of the resin, and the grease filled inside the bearing Can be prevented from leaking, and the life of the bearing can be extended.

  In the bearing holding structure of the steam turbine generator, the annular resin member can be fitted into a recessed groove formed in the generator casing.

  Further, in the bearing holding structure of the steam turbine generator, the annular resin member is formed by injecting molten resin into the concave groove formed in the generator casing and the concave groove formed in the bearing to solidify. You can also

  According to the bearing holding structure of the steam turbine generator of the present invention, the behavior of the bearing can be stabilized, the grease filled in the bearing can be reliably prevented from leaking and scattering, and the life of the bearing can be extended. An excellent effect can be achieved.

1 is a side sectional view showing a first embodiment of a bearing holding structure for a steam turbine generator according to the present invention. It is a principal part expanded sectional view in the 1st Example of the bearing holding structure of the steam turbine generator of this invention. It is a sectional side view which shows the 2nd Example of the bearing holding structure of the steam turbine generator of this invention. It is a principal part expanded sectional view in the 2nd Example of the bearing holding structure of the steam turbine generator of this invention. It is a sectional side view which shows the 3rd Example of the bearing holding structure of the steam turbine generator of this invention. It is a principal part expanded sectional view in the 3rd Example of the bearing holding structure of the steam turbine generator of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 and FIG. 2 show a first embodiment of a bearing holding structure for a steam turbine generator according to the present invention. Reference numeral 1 denotes a rotor having shafts 2 and 3 on both sides. The turbine 4 is integrally fitted. Reference numeral 5 denotes a turbine housing formed so as to accommodate the turbine 4. The turbine housing 5 has a gas passage 6 for guiding steam to the turbine 4, and after rotating the turbine 4. A discharge passage 6a for exhausting the steam having a low pressure is provided.

  Reference numeral 7a denotes a stator housing constituting the generator casing 7 that is integrally assembled to the turbine housing 5 with fixing bolts 8. The stator housing 7a projects toward the inner peripheral side so as to approach the one shaft 2 and further to the inner side. It has a cylindrical protruding portion 9 that protrudes in an annular shape so that its peripheral portion approaches the rotor 1, and is formed so as to surround the rotor 1 in a motor stator housing portion 10 formed by the cylindrical protruding portion 9. One end (the left end in the example of FIG. 1) of the motor stator 11 on the turbine housing 5 side is accommodated and held. Further, a first bearing 12 is disposed between the inner peripheral portion of the cylindrical protruding portion 9 and the one shaft 2 so as to rotatably support the one shaft 2. The motor stator 11 includes a stator 11a composed of an inner coil and a stator sleeve 11b fitted on the outer periphery of the stator 11a.

  Reference numeral 7b denotes a bearing flange that constitutes the generator casing 7 together with the stator housing 7a so as to be integrally assembled to the stator housing 7a by a fixing bolt 13. A cylindrical projecting portion 14 projecting in the axial direction inside the other end portion (right end portion in the example of FIG. 1) so as to hold the other end portion of the motor stator 11, and further, A second bearing 15 is disposed between the inner peripheral portion of the cylindrical protrusion 14 and the other shaft 3 of the rotor 1 so as to rotatably support the other shaft 3.

  A plurality of vanes 17 are arranged on the end surface of the stator housing 7a integrally assembled with the turbine housing 5 in the circumferential direction with respect to the nozzle portion 16 that guides the steam of the gas passage 6 to the turbine 4 from the circumferential direction. A nozzle flange 18 is attached and fixed to each vane 17.

  Further, a connector mounting cover 19 is integrally assembled to the bearing flange 7b by fixing bolts 20, and is electrically connected to the stator mounting 11 of the motor stator 11 via a cord 21. The generator connector 22 is integrally assembled by a fixing bolt 23.

  Furthermore, between the turbine housing 5 and the stator housing 7a, between the outer periphery of the motor stator 11 and the stator housing 7a, between the stator housing 7a and the bearing flange 7b, and between the bearing flange 7b and the connector mounting cover. A seal member made of an O-ring or the like is interposed between the seal member 19 and the seal member 24 provided between the outer periphery of the motor stator 11 and the stator housing 7a. The seal member 24 is formed on the stator housing 7a. The cooling water flowing through a supply / discharge port (not shown) is sealed with respect to the cooling water passage 25 for the motor stator 11.

The stator housing 7a and the bearing flange 7b constituting the generator casing 7 are made of an aluminum alloy, and the linear expansion coefficient thereof is 24 × 10 ⁻⁶ [1 / ° C.], whereas the first bearing 12 and the second bearing 15 are made of bearing steel and have a linear expansion coefficient of 12.5 × 10 ⁻⁶ [1 / ° C.]. In the case of the first embodiment, the generator casing 7 and the bearing 12 and 15, an annular resin member 26 having a linear expansion coefficient larger than that of the generator casing 7 is interposed.

As the annular resin member 26, for example, nylon 6 which is a polyamide resin can be selected, and its linear expansion coefficient is 80 × 10 ⁻⁶ [1 / ° C.], and the linear expansion coefficient of the generator casing 7 is About three times as much as As the annular resin member 26, for example, polyacetal (linear expansion coefficient is 90 × 10 ⁻⁶ [1 / ° C.]), polypropylene (linear expansion coefficient is 110 × 10 ⁻⁶ [1] instead of 6 nylon. / ° C]) or polycarbonate (linear expansion coefficient is 70 × 10 ⁻⁶ [1 / ° C]) or the like.

Incidentally, the outer diameter of the bearings 12 and 15 is D = φ17 [mm], and the clearance generated between the generator casing 7 and the outer rings of the bearings 12 and 15 during operation is, for example, about c≈12 [μm]. In this case, as shown in FIG. 2, annular concave grooves 9a and 14a having a depth of about h = 2 [mm] and a width of about w = 2 [mm] are formed in advance in the cylindrical projection of the stator housing 7a. On the inner peripheral side of the cylindrical protrusion 14 of the portion 9 and the bearing flange 7b, it is formed so as to be positioned on the extension line of the center line O of the balls (see FIG. 1) of the bearings 12 and 15, The annular resin member 26 may be inserted into 14a. Here, when the temperature difference between the manufacturing time (20 [° C.] as normal temperature) and the operation time (80 [° C.]) is ΔT, an annular resin member that is fitted to the outer periphery of the bearings 12 and 15. When the expansion amount of 26 is Δe,
Δe = D × ΔT × 80 × 10 ⁻⁶
= 17 × (80-20) × 80 × 10 ⁻⁶
= 0.0816 [mm]
≒ 80 [μm]
Therefore, considering the elastic deformation of the annular resin member 26, the outer diameter of the annular resin member 26 is manufactured to be about 20 to 50 [μm] smaller than the inner diameter of the concave grooves 9a and 14a. It is preferable that a gap is formed between the inner peripheral surfaces of the grooves 9a and 14a and the outer peripheral surface of the annular resin member 26 during manufacturing.

  Next, the operation of the first embodiment will be described.

  The steam introduced into the gas passage 6 of the turbine housing 5 is guided to the turbine 4 through the vane 17 from the nozzle portion 16, and the steam having a low pressure after the turbine 4 is rotationally driven is discharged from the discharge passage 6a. However, when the turbine 4 is driven to rotate, the rotor 1 rotates with respect to the stator 11a of the motor stator 11 to generate power, and the stator 11a of the motor stator 11 is electrically connected to the stator 11a via the cord 21. Electricity is taken out from the connected generator connector 22.

Here, the stator housing 7a and the bearing flange 7b constituting the generator casing 7 are formed of an aluminum alloy, and the linear expansion coefficient thereof is 24 × 10 ⁻⁶ [1 / ° C.], whereas the first The bearing 12 and the second bearing 15 are made of bearing steel and have a linear expansion coefficient of 12.5 × 10 ⁻⁶ [1 / ° C.]. In the case of the first embodiment, the generator casing 7 and Between the bearings 12 and 15, when the annular resin member 26 (for example, 6 nylon is selected) whose linear expansion coefficient is several times (two or more integer times, for example, three times) or more than the generator casing 7, Since its linear expansion coefficient is 80 × 10 ⁻⁶ [1 / ° C.], the generator casing 7 and the bearing 12 of the steam turbine generator manufactured by being assembled at normal temperature (20 [° C.]) are manufactured. , 15 is caused by steam flowing during operation. Even if the temperature rises to about 80 [° C.] and the clearance between the generator casing 7 and the outer rings of the bearings 12 and 15 expands due to a difference in expansion due to the temperature rise, the annular resin member 26 is moved to the generator. There is a concern that rattling may occur between the generator casing 7 and the bearings 12 and 15 due to sufficient expansion between the casing 7 and the outer rings of the bearings 12 and 15 to compensate for the expanded clearance. Disappear.

  As a result, when the steam turbine generator is operated, it is avoided that the behavior of the bearings 12 and 15 becomes unstable as in the prior art, and the vibration is attenuated by the damping of the resin. It becomes difficult for the grease filled in to leak out, and the life of the bearings 12 and 15 can be extended.

  Thus, the behavior of the bearings 12 and 15 can be stabilized, the grease filled in the bearings 12 and 15 can be reliably prevented from leaking and scattering, and the life of the bearings 12 and 15 can be extended.

  3 and 4 show a second embodiment of the bearing holding structure for a steam turbine generator according to the present invention. In the figure, the parts denoted by the same reference numerals as those in FIGS. 1 and 2 represent the same thing. The basic configuration is the same as that of the first embodiment shown in FIGS. 1 and 2, but the feature of the second embodiment is that it is formed in the generator casing 7 as shown in FIGS. The annular resin member 26 is formed by injecting molten resin into the recessed grooves 9a, 14a and the recessed grooves 12a, 15a formed in the bearings 12, 15 and solidifying them.

  In the case of the second embodiment, as shown in FIG. 4, the concave grooves 9a, 14a are annular with a depth of h = 2 [mm] and a width of about w = 2 [mm], and the generator casing 7 The cylindrical projection 9 of the stator housing 7a and the cylindrical projection 14 of the bearing flange 7b are located on the inner peripheral side of the bearing 12 and 15 on the extension line of the center line O of the balls (see FIG. 3). Correspondingly, the concave grooves 12a and 15a are annular with a depth of i = 0.5 [mm] and a width of about w = 2 [mm]. Further, the bearings 12 and 15 are formed so as to be positioned on an extension line of the center line O of the balls (see FIG. 3).

  The concave grooves 9a and 14a are connected to inlets 9b and 14b having a hole diameter of about φj = 1 [mm], and bearings 12 and 15 fitted to the shafts 2 and 3 of the rotor 1, The turbine housing 5 and the connector mounting cover 19 are attached to the inner peripheral part of the cylindrical protrusion 9 of the stator housing 7a and the inner peripheral part of the cylindrical protrusion 14 of the bearing flange 7b. Before being attached to the stator housing 7a and the bearing flange 7b, the molten resin can be injected from the injection ports 9b and 14b to be solidified.

  In the case where 6 nylon is used as the molten resin, the melting point is 225 [° C.], so the resin injection temperature is about 250 [° C.], and the molten resin becomes the concave grooves 9a and 14a and the concave grooves 12a, The annular resin member 26 that is inserted between the generator casing 7 and the bearings 12 and 15 contracts by being injected into 15a and being solidified by lowering the temperature to room temperature (20 [° C.]). The amount of molten resin injected may be adjusted in view of the amount of shrinkage and the amount of expansion of the annular resin member 26 when the temperature rises to about 80 [° C.] during operation.

  Further, the clearance between the generator casing 7 and the outer ring of the bearings 12 and 15 is about c≈12 [μm] during operation, but the molten resin is used as the concave grooves 9a and 14a and the concave grooves 12a and 15a. When it is injected into the liquid, it is 12 [μm] or less, so there is no fear that the molten resin leaks from this gap.

  In the second embodiment shown in FIGS. 3 and 4, an annular resin member 26 solidified by pouring molten resin is interposed between the generator casing 7 and the bearings 12 and 15. Therefore, as in the case of the first embodiment shown in FIGS. 1 and 2, the generator casing 7 and the bearings 12 and 15 of the steam turbine generator assembled and manufactured at room temperature (20 [° C.]) are in operation. Even if the temperature rises to about 80 [° C.] due to the circulating steam, and the clearance between the generator casing 7 and the outer ring of the bearings 12 and 15 expands due to the expansion difference due to the temperature rise, the annular resin member 26 is expanded between the generator casing 7 and the outer rings of the bearings 12 and 15 to expand between the generator casing 7 and the bearings 12 and 15 by sufficient expansion to compensate for the expanded clearance. Outs caused worry is eliminated.

  As a result, also in the second embodiment shown in FIGS. 3 and 4, it is possible to avoid the behavior of the bearings 12 and 15 from becoming unstable as in the prior art during the operation of the steam turbine generator, The vibration is attenuated by the damping of the resin, the grease filled in the bearings 12 and 15 is hardly leaked, and the life of the bearings 12 and 15 can be extended.

  Thus, in the second embodiment shown in FIGS. 3 and 4 as well, in the same way as in the first embodiment shown in FIGS. 1 and 2, the behavior of the bearings 12 and 15 is stabilized, and the bearings 12 and 15 are filled. Thus, it is possible to reliably prevent the leaked grease from leaking and scattering, and to extend the life of the bearings 12 and 15.

  5 and 6 show the third embodiment of the bearing holding structure of the steam turbine generator according to the present invention. In the figure, the same reference numerals as those in FIGS. 3 and 4 denote the same parts. The basic configuration is the same as that of the second embodiment shown in FIGS. 3 and 4, but the feature of the third embodiment is that, as shown in FIGS. 5 and 6, the molten resin is injected and solidified. A plurality of (two in the illustrated example) annular resin members 26 are formed on the bearings 12 and 15, respectively.

  In the case of the third embodiment, as shown in FIG. 6, an annular concave groove 9 a having a depth of h = 2 [mm] and a width of about w = 1 [mm] is formed as a stator constituting the generator casing 7. Formed on the inner peripheral side of the cylindrical projection 9 of the housing 7a so that the separation distance is about x = 2 [mm] across the center line O of the ball of the bearing 12 (see FIG. 5). An annular groove 12a having a depth of i = 0.5 [mm] and a width of about w = 1 [mm] is formed on the outer peripheral side of the bearing 12 and the center of the ball of the bearing 12 (see FIG. 5). Two annular concave grooves 14a having a depth of h = 2 [mm] and a width of about w = 1 [mm] are formed so that the separation distance is about x = 2 [mm] across the line O. The inner peripheral side of the cylindrical projection 14 of the bearing flange 7b constituting the generator casing 7 is separated from the center line O of the ball of the bearing 15 (see FIG. 5). The distance is formed to be about x = 2 [mm], and corresponding to this, two annular concave grooves 15a having a depth of i = 0.5 [mm] and a width of about w = 1 [mm] are formed. These are formed on the outer peripheral side of the bearing 15 so that the separation distance is about x = 2 [mm] across the center line O of the ball of the bearing 15 (see FIG. 5).

  In addition, an inlet 9b having a hole diameter of about φj = 1 [mm] is connected to each of the two concave grooves 9a, and a hole diameter of each of the two concave grooves 14a is φj = 1 [mm]. The bearings 12 and 15 fitted to the shafts 2 and 3 of the rotor 1 are connected to the inner peripheral portion of the cylindrical projecting portion 9 of the stator housing 7a constituting the generator casing 7. The two inlets 9b are attached to the inner peripheral portion of the cylindrical projection 14 of the bearing flange 7b and before the turbine housing 5 and the connector mounting cover 19 are attached to the stator housing 7a and the bearing flange 7b. The molten resin can be injected and solidified from the two injection ports 14b.

  In the third embodiment shown in FIGS. 5 and 6, when 6 nylon is used as the molten resin, the melting point is 225 [° C.] as in the second embodiment shown in FIGS. Therefore, the resin injection temperature is about 250 [° C.], and the molten resin is injected into the concave grooves 9a, 14a and the concave grooves 12a, 15a, and is solidified by lowering the temperature to room temperature (20 [° C.]). Since the annular resin member 26 that is interposed between the generator casing 7 and the bearings 12 and 15 contracts, the amount of contraction and the cyclic resin when the temperature rises to about 80 [° C.] during operation. The injection amount of the molten resin may be adjusted in view of the expansion amount of the member 26.

  In the third embodiment shown in FIGS. 5 and 6, the clearance between the generator casing 7 and the outer rings of the bearings 12 and 15 is the same as in the second embodiment shown in FIGS. During operation, c≈12 [μm], but when the molten resin is poured into the concave grooves 9a, 14a and the concave grooves 12a, 15a, it is 12 [μm] or less. There is no worry of resin leaking.

  In the third embodiment shown in FIGS. 5 and 6, an annular resin member 26 solidified by pouring molten resin is interposed between the generator casing 7 and the bearings 12 and 15. Therefore, as in the case of the first embodiment shown in FIGS. 1 and 2 and the second embodiment shown in FIGS. 3 and 4, the power generation of the steam turbine generator manufactured by being assembled at normal temperature (20 [° C.]). The temperature of the machine casing 7 and the bearings 12 and 15 rises to about 80 [° C.] due to steam flowing during operation, and the clearance between the generator casing 7 and the outer ring of the bearings 12 and 15 is accompanied by the temperature rise. Even if the annular resin member 26 expands due to an expansion difference, the annular resin member 26 expands sufficiently between the generator casing 7 and the outer rings of the bearings 12 and 15 to compensate for the expanded clearance. Worry about backlash occurs between the grayed 7 and the bearing 12 and 15 is eliminated.

  As a result, also in the third embodiment shown in FIG. 5 and FIG. 6, it is avoided that the behavior of the bearings 12 and 15 becomes unstable during the operation of the steam turbine generator as in the prior art, The vibration is attenuated by the damping of the resin, the grease filled in the bearings 12 and 15 is hardly leaked, and the life of the bearings 12 and 15 can be extended.

  In addition, in the third embodiment shown in FIGS. 5 and 6, the annular resin member 26 formed by injecting and solidifying molten resin is symmetrical with respect to the center line O of the balls of the bearings 12 and 15. Since the two are arranged so as to be distributed, the bearings 12 and 15 can be supported in a very balanced manner, which is effective in stabilizing the behavior of the bearings 12 and 15.

  Thus, in the third embodiment shown in FIGS. 5 and 6, the behavior of the bearings 12 and 15 is the same as in the first embodiment shown in FIGS. 1 and 2 and the second embodiment shown in FIGS. The grease filled in the bearings 12 and 15 can be reliably prevented from leaking and scattering, and the life of the bearings 12 and 15 can be extended.

  In addition, the bearing holding structure of the steam turbine generator of the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Rotor 2 axis | shaft 3 axis | shaft 4 Turbine 7 Generator casing 7a Stator housing 7b Bearing flange 9 Cylindrical protrusion part 9a Concave groove 11 Motor stator 12 Bearing 12a Concave groove 14 Cylindrical protrusion part 14a Concave groove 15 Bearing 15a Concave groove 26 Annular resin Element

Claims (3)

Steam turbine power generation in which a rotor having a shaft on both sides and a turbine provided on one shaft is rotatably supported with respect to a generator casing via a bearing made of a material having a linear expansion coefficient different from that of the generator casing. Bearing holding structure of the machine,
An annular resin member is provided between the generator casing and the bearing,
A bearing holding structure for a steam turbine generator, wherein a linear expansion coefficient of the annular resin member is larger than a linear expansion coefficient of the generator casing.   The bearing holding structure for a steam turbine generator according to claim 1, wherein the annular resin member is fitted into a recessed groove formed in the generator casing.   2. The steam turbine generator according to claim 1, wherein the annular resin member is formed by injecting molten resin into a concave groove formed in the generator casing and a concave groove formed in the bearing to solidify. Bearing holding structure.

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