JPWO2014162594A1 - Thrust bearing device, lubricating oil supply method thereof, rotating machine and steam turbine - Google Patents

Abstract

The present invention provides a thrust bearing device capable of reducing the supply amount of lubricating oil supplied while maintaining the maximum temperature of the pad surface below an allowable value. A thrust bearing device according to the present invention is a thrust bearing device that is installed on the outer peripheral side of a rotating shaft and receives an axial load of the rotating shaft via a thrust collar fixed to a bearing base, the thrust bearing comprising: A thrust plate having a plurality of pad surfaces opposed to the thrust collar in the axial direction; an oil groove having an opening on the inner peripheral side is formed on the inner peripheral side upstream of the pad surface; and the pad surface An oil supply land portion is formed on the upstream outer peripheral side, and a communication hole for guiding lubricating oil from the outside is connected to the oil supply land portion.

Description

  The present invention relates to a thrust bearing device, a lubricating oil supply method thereof, a rotating machine, and a steam turbine, and more particularly to a thrust bearing device suitable for receiving an axial load of a rotating shaft and suppressing axial displacement of the rotating shaft, and the lubrication thereof. The present invention relates to an oil supply method, a rotating machine, and a steam turbine.

  Generally, a steam turbine used in a thermal power generation facility or the like is connected to a generator via a rotating shaft. The rotating shaft is installed so as to extend in the horizontal direction, and a plurality of journal bearings that receive a radial load including the weight of the rotating shaft are provided. In the steam turbine, the fluid force fluctuates depending on the rotation speed and load state of the rotation shaft, and an axial load on the rotation shaft is also generated by the fluid force. Therefore, a thrust bearing is provided that receives the axial load of the rotating shaft and suppresses the axial displacement of the rotating shaft.

  As the above-described thrust bearing, there is a taper land bearing as shown in Patent Document 1 and Non-Patent Document 1 as a model with a small number of parts and low cost.

  In Patent Document 1, a port is formed in a flat portion of a land portion that is inclined in the radial direction from the bearing shaft and forms a flat portion, and the oil film pressure is made higher than that of the land portion inclined in the port. Thus, there is described a thrust bearing that prevents a significant decrease in load capacity even at a low rotational speed at which the load capacity significantly decreases.

  Further, in Non-Patent Document 1, the lubricating oil supplied to the taper land bearing flows into oil grooves provided radially, and then, along with the rotation of the thrust collar attached to the rotating shaft, the thrust collar and the thrust bearing pad. Flowing between the surface (formed from the taper portion and land portion) to form an oil film. At this time, the temperature of the lubricating oil rises due to the shearing force, so the upstream side of the thrust collar in the rotational direction on the pad surface Then, although the temperature of the lubricating oil is relatively low, the temperature of the lubricating oil is relatively high on the downstream side in the rotation direction of the rotating shaft on the pad surface. That is, it is described that a circumferential temperature distribution occurs in the lubricating oil on the pad surface.

Japanese Utility Model Publication No. 54-158157

Japan Tribology Society, Tribology Handbook, Yokendo (2001), p58

  However, in the prior art described in Patent Document 1 and Non-Patent Document 1 described above, the lubricating oil that flows into the oil groove includes the supplied low-temperature lubricating oil and the exhaust oil that has reached a high temperature on the other pad surface. The temperature of the lubricating oil flowing into the pad surface is not necessarily low enough. For this reason, in order to reduce the lubricating oil temperature in the oil groove, it is necessary to increase the amount of oil supplied, and there is room for improvement in terms of the amount of oil supplied.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a thrust bearing device capable of reducing the supply amount of lubricating oil supplied while maintaining the maximum temperature of the pad surface below an allowable value, and An object of the present invention is to provide a lubricating oil supply method, a rotating machine, and a steam turbine.

  In order to achieve the above object, the thrust bearing device of the present invention is a thrust bearing device that is installed on the outer peripheral side of the rotating shaft and receives the axial load of the rotating shaft through a thrust collar fixed to the bearing base. The thrust bearing includes a thrust plate having a plurality of pad surfaces that are axially opposed to the thrust collar, and an oil groove having an opening on the inner peripheral side is provided on the inner peripheral side upstream of the pad surface. In addition, an oil supply land portion is formed on the outer peripheral side upstream of the pad surface, and a communication hole for guiding lubricating oil from the outside is connected to the oil supply land portion.

  In order to achieve the above object, a rotating machine according to the present invention is a rotating machine including a thrust bearing device that receives an axial load of a rotating shaft, and the thrust bearing device having the above-described configuration is used as the thrust bearing device. It is used.

  In order to achieve the above object, the steam turbine according to the present invention includes a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine that respectively correspond to the steam pressure. A steam turbine including a plurality of journal bearing devices connected via a rotating shaft and receiving a radial load of the rotating shaft; and a thrust bearing device receiving an axial load of the rotating shaft, The thrust bearing device is a thrust bearing device configured as described above.

  Furthermore, in order to achieve the above object, the method of supplying the lubricating oil for the thrust bearing device according to the present invention provides an axial direction of the rotary shaft via a thrust collar installed on the outer peripheral side of the rotary shaft and fixed to the bearing base. A method of supplying lubricating oil to a thrust bearing device that receives a load, and a temperature that flows out from the pad surface on an inner peripheral side where an increase in oil film temperature upstream of the plurality of pad surfaces facing the thrust collar in the axial direction is small. The lubricating oil is fed back from the oil groove formed on the inner peripheral side of the pad surface, and the outer peripheral side having a large temperature rise upstream of the pad surface is lubricated at a low temperature from the outside. The oil is supplied from an oil supply land portion formed on the outer peripheral side upstream of the pad surface.

  According to the present invention, it is possible to reduce the supply amount of lubricating oil to be supplied while keeping the maximum temperature of the pad surface below an allowable value.

It is a fragmentary sectional view (equivalent to the II cross section of FIG. 2) which shows Example 1 of the thrust bearing apparatus of this invention. It is a perspective view which shows a part of thrust plate in Example 1 of the thrust bearing apparatus of this invention. It is a figure which shows sectional drawing of the thrust plate in the AA cross section of FIG. 2, and the circumferential temperature distribution of an oil film. FIG. 3 is a sectional view of a thrust plate and a circumferential temperature distribution of an oil film in a BB section of FIG. 2. It is a fragmentary sectional view (equivalent to the II cross section of FIG. 2) which shows Example 2 of the thrust bearing apparatus of this invention. It is a perspective view which shows a part of thrust plate in Example 2 of the thrust bearing apparatus of this invention. It is a figure which shows sectional drawing of the thrust plate in the A'-A 'cross section of FIG. 6, and the circumferential direction temperature distribution of an oil film. It is a schematic block diagram which shows the steam turbine which employ | adopted the thrust bearing apparatus of this invention.

  Hereinafter, based on the illustrated embodiment, a thrust bearing device of the present invention, a lubricating oil supply method thereof, a rotating machine, and a steam turbine will be described. In addition, in each Example, the same code | symbol is used for the same component.

  1 and 2 show a first embodiment of a thrust bearing device of the present invention.

  As shown in the figure, the thrust bearing device 100 of this embodiment is installed on the outer peripheral side of the rotating shaft 1 so as to receive the axial load of the rotating shaft 1 via the thrust collar 2 fixed to the bearing base 3. It is configured.

  That is, the thrust bearing device 100 of this embodiment includes a substantially annular thrust plate 4 fixed to the bearing base 3, and a thrust collar 2 is provided on the outer peripheral side of the rotating shaft 1, and the rotating shaft 1 and the thrust collar are provided. The thrust plate 4 is disposed so as to face the thrust collar 2 in the axial direction.

  A plurality of pad surfaces 10 including a taper portion 11 and land portions 12 are formed in the circumferential direction on the surface (sliding surface) of the thrust plate 4 facing the thrust collar 2 in the circumferential direction. The taper portion 11 of the pad surface 10 is formed with an inclined surface that becomes higher along the rotation direction of the rotary shaft 1, and the land portion 12 of the pad surface 10 is a flat surface formed continuously at the highest position of the taper portion 11. A surface is formed.

  In the present embodiment, an opening is provided on the inner peripheral side at the innermost side of the lowest position of the tapered portion 11 which is a boundary portion in the circumferential direction of each pad surface 10 formed in the circumferential direction. An oil groove 9 is formed, and an oil supply land 20 part is formed on the outer peripheral side thereof. An oil supply groove 8 is formed in the oil supply land 20, and a communication hole 7 is provided in the oil supply groove 8. The communication hole 7 communicates with one end of an oil supply hole 6 provided in the bearing base 3. The other end of the oil supply hole 6 is connected to an oil supply groove 5 provided on the outer periphery of the bearing base 3.

  Next, the operation according to the configuration of this embodiment will be described.

  First, the lubricating oil whose pressure has been increased by an external pump (not shown) or the like is guided to an oil supply groove 5 provided on the outer periphery of the bearing base 3. The lubricating oil guided to the oil supply groove 5 fills the oil supply groove 5 so that the pressure on the entire circumference is substantially constant, and then is connected to the oil supply holes 6 provided in the oil supply groove 5 and a plurality thereof. It passes through the communication hole 7 and flows into the oil supply groove 8. The lubricating oil supplied to the oil supply groove 8 flows to the pad surface 10 including the tapered portion 11 and the land portion 12 as the thrust collar 2 rotates.

  At this time, since the gap between the tapered portion 11 and the thrust collar 2 is gradually narrowed, dynamic pressure is generated due to the wedge effect. Since this dynamic pressure is also maintained in the land portion 12, a high-pressure oil film is formed over a wide range of the pad surface 10. By this oil film, the thrust plate 4 can support the axial load from the thrust collar 2 without hindering the rotation of the thrust collar 2.

  The flow of the oil film on the pad surface 10 is indicated by arrows a, b and c in FIG. That is, at the center of the pad surface 10 in the radial direction, as indicated by the arrow c, the radial position remains constant and flows in the circumferential direction. On the other hand, the flow on the outer peripheral side with respect to the center in the radial direction of the pad surface 10 is pushed out to the outer peripheral side by the pressure of the oil film, as indicated by an arrow a. Similarly, the flow on the inner peripheral side with respect to the center in the radial direction of the pad surface 10 is pushed out toward the inner peripheral side by the pressure of the oil film, as indicated by an arrow b. The lubricating oil pushed out to the inner peripheral side flows into the oil groove 9 downstream in the rotation direction due to the influence of centrifugal force given by shearing with the thrust collar 2. Like the lubricating oil supplied to the oil supply groove 8, the lubricating oil accumulated in the oil groove 9 flows to the pad surface 10 along with the rotation of the thrust collar 2, and forms part of the oil film.

  Next, the effect of the present embodiment will be described with reference to FIGS.

  3 shows a cross section of the thrust plate 4 (lower part of FIG. 3) and a circumferential temperature distribution of the oil film (upper part of FIG. 3) in the AA cross section of FIG. 2, and FIG. 4 shows a BB cross section of FIG. The cross section of the thrust plate 4 in FIG. 4 (lower stage in FIG. 4) and the circumferential temperature distribution of the oil film (upper stage in FIG. 4) are shown.

  3 represents the circumferential position of the thrust plate 4 and the vertical axis represents the temperature of the oil film at the circumferential position of the thrust plate 4. The lower part of FIG. 3 represents the state which looked at the cross section along the dotted line AA of the thrust plate 4 from the outer peripheral side. Similarly, the upper horizontal axis of FIG. 4 represents the circumferential position of the thrust plate 4, and the vertical axis represents the temperature of the oil film at the circumferential position of the thrust plate 4. The lower part of FIG. 4 is a cross section taken along the dotted line BB of the thrust plate 4 as seen from the outer peripheral side.

  First, the oil film temperature on the dotted line AA in FIG. 2, which is the outer peripheral side of the pad surface 10 in the radial direction, will be described with reference to FIG.

  Normally, in the taper portion 11 and the land portion 12, the oil film temperature rises as it proceeds in the rotation direction due to shearing heat generated by the rotation of the thrust collar 2, and reaches a temperature T2a. After that, when flowing into the oil supply groove 8 of the oil supply land portion 20 provided connected to the rear end portion of the land portion 12, the temperature is lowered to T1a because it is mixed with the lubricating oil having the temperature T0 supplied from the communication hole 7. To do. When the oil flows out from the oil supply groove 8 to the tapered portion 11, the temperature rises again, and the above is repeated after reaching the temperature T2a.

  Next, the oil film temperature on the dotted line BB in FIG. 2 that is on the inner peripheral side of the pad surface 10 in the radial direction will be described with reference to FIG.

  Normally, in the taper portion 11 and the land portion 12, the oil film temperature rises as it advances in the rotation direction due to shearing heat generated by the rotation of the thrust collar 2, and reaches a temperature T2b. As indicated by the arrow b 'in FIG. 2, in the oil groove 9 provided on the downstream side of the land portion 12, the lubricating oil that has flowed out from the upstream pad surface 10 to the inner peripheral side flows. The mixed oil film temperature decreases to T1b. When the oil flows out from the oil groove 9 to the tapered portion 11, the temperature rises again, and the above is repeated after reaching the temperature T2b.

  Here, the temperature of each part is compared. First, T2a and T2b are almost the same. Since the temperature of the lubricating oil mixed in the oil groove 9 on the dotted line BB is higher than the temperature T0 of the lubricating oil mixed in the oil supply groove 8 on the dotted line A-A, the temperature of the lubricating oil indicated by the arrow b ′ in FIG. T1b. Since the temperature rise in the taper part 11 and the land part 12 is proportional to the peripheral speed, the dotted line AA on the outer peripheral side is larger than the dotted line BB on the inner peripheral side, and (T2a-T1a)> (T2b- T1b). When combined with the magnitude relationship between T1a and T1b described above, T2a and T2b are substantially the same.

  Conventionally, low temperature (T0) lubricating oil is supplied to the inner and outer circumferences so that the temperature of the oil film flowing into the tapered portion 11 is substantially the same on the outer circumference (T1a) and the inner circumference (T1b). Therefore, T2a> T2b. Since the amount of oil supply is set so that T2a is less than or equal to the allowable value, T2b has decreased more than necessary, and it can be said that the amount of oil supply is excessive.

  On the other hand, in this embodiment, low temperature (T0) lubricating oil is supplied only to the outer peripheral side, and sufficient lubricating oil is supplied to reduce T2a by a necessary amount. Can do.

  That is, while supplying low-temperature lubricating oil from the outside to the outer peripheral side where the oil film temperature rise is large, the inner peripheral side where the oil film temperature rise is small flows out of the pad surface 10 to recirculate the lubricating oil whose temperature is high. The oil is supplied from the oil groove 9. In this way, since the lubricating oil from the outside is not supplied to the inner peripheral side, the total amount of oil supply can be reduced.

  Therefore, by using the present embodiment, it is possible to reduce the supply amount of the lubricating oil supplied while keeping the maximum temperature of the pad surface below the allowable value.

  A groove may be provided between the land portion 12 and the adjacent oil supply land portion 20. When there is no groove, the pressure of the oil supply groove 8 is increased under the influence of the high oil film pressure of the oil supply land portion 20, and the flow from the communication hole 7 may be hindered. When there is a groove, the pressure of the oil supply groove 8 can be kept low, and there is an effect that the flow from the communication hole 7 is not hindered.

  5 and 6 show a first embodiment of the thrust bearing device of the present invention.

  In the present embodiment shown in the figure, the inner diameter of the thrust plate 4 increases toward the surface side (thrust collar 2 side) as shown in FIG. 5, and as shown in FIG. The downstream side is open.

  That is, the distance L2 from the axis center of the rotating shaft 1 on the inner surface side (bearing base 3 side) and the thrust plate 4 to the distance L1 from the axis center of the rotating shaft 1 on the surface side (thrust collar 2 side) to the thrust plate 4. The structure is larger (L1> L2) and the downstream side of the oil supply groove 8 is open. Other configurations are the same as those of the first embodiment.

  According to this embodiment, since the inner diameter of the thrust plate 4 increases toward the surface side (L1> L2), the upstream pad surface as indicated by the arrow b ′ in FIG. Lubricating oil that has flowed out from 10 to the inner peripheral side can be efficiently introduced into the oil groove 9. Further, since the downstream side of the oil supply groove 8 is opened, the amount of low-temperature lubricating oil from the outside flowing out from the oil passage hole 7 increases.

  That is, as shown in FIG. 7, the temperature drop in the oil supply groove 8 can be lowered to T1a ′ lower than T1a obtained in the first embodiment.

  Even with this configuration of the present embodiment, the same effects as those of the first embodiment can be obtained.

  Next, an example of a rotary machine provided with the above-described thrust bearing device 100 will be described with reference to FIG. FIG. 8 is a diagram illustrating a configuration of a steam turbine including the thrust bearing device 100 described above.

  In the figure, the steam turbine is composed of a high-pressure turbine 30, an intermediate-pressure turbine 31, and a low-pressure turbine 32 that respectively correspond to the steam pressure. The high-pressure turbine 30, the intermediate-pressure turbine 31, the low-pressure turbine 32, and the generator 33 are included. It is connected via a rotating shaft 1. A plurality of journal bearing devices 34 that receive the radial load of the rotating shaft 1 and the above-described thrust bearing device 100 that receives the axial load of the rotating shaft 1 are provided.

  In such a steam turbine, by reducing the amount of oil supplied to the thrust bearing device 100, it is possible to reduce the size of auxiliary equipment and accessories (for example, pumps and piping) for oil supply. Therefore, the steam turbine can be made compact.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Rotary shaft, 2 ... Thrust collar, 3 ... Bearing base, 4 ... Thrust plate, 5 ... Oil supply groove, 6 ... Oil supply hole, 7 ... Communication hole, 8 ... Oil supply groove, 9 ... Oil groove, 10 ... Pad Surface 11, taper portion, 12 land portion, 20 oil filling land portion, 30 high pressure turbine, 31 medium pressure turbine, 32 low pressure turbine, 33 generator, 34 journal bearing, 100 thrust bearing device.

Claims (9)

A thrust bearing device that is installed on the outer peripheral side of the rotating shaft and receives an axial load of the rotating shaft through a thrust collar fixed to a bearing base,
The thrust bearing includes a thrust plate having a plurality of pad surfaces opposed to the thrust collar in the axial direction, and an oil groove having an opening on the inner peripheral side is formed on the inner peripheral side upstream of the pad surface. The thrust bearing device is characterized in that an oil supply land portion is formed on the outer peripheral side upstream of the pad surface, and a communication hole for guiding lubricating oil from the outside is connected to the oil supply land portion. The thrust bearing device according to claim 1,
The pad surface includes a taper portion that forms an inclined surface that rises in the rotation direction on a surface facing the thrust collar, and a land portion that forms a flat surface continuous at the highest position of the taper portion. The thrust groove device is characterized in that the oil groove is formed on the inner peripheral side of the lowest position of the taper portion, and the oil supply land portion is formed on the outer peripheral side of the oil groove. The thrust bearing device according to claim 1 or 2,
The thrust bearing device according to claim 1, wherein the oil groove and the oil supply land portion are formed at a boundary portion in a circumferential direction of the plurality of pad surfaces. The thrust bearing device according to any one of claims 1 to 3,
The oil supply land portion includes an oil supply groove and a communication hole provided in the oil supply groove, and the communication hole is connected to one end of an oil supply hole provided in the bearing base. A thrust bearing device, wherein the other end is connected to an oil supply groove provided on an outer peripheral portion of the bearing base. The thrust bearing device according to any one of claims 1 to 4,
A thrust bearing device, wherein an inner diameter of the thrust plate increases toward the surface side. The thrust bearing device according to claim 4 or 5,
A thrust bearing device, wherein a downstream side of the oil supply groove is opened. A rotary machine including a thrust bearing device that receives an axial load of a rotary shaft,
A rotary machine using the thrust bearing device according to any one of claims 1 to 6 as the thrust bearing device. A high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine respectively corresponding to the steam pressure, the high-pressure turbine, the intermediate-pressure turbine, the low-pressure turbine and a generator are connected via a rotating shaft, and the radial direction of the rotating shaft A steam turbine comprising a plurality of journal bearing devices for receiving a load and a thrust bearing device for receiving an axial load of the rotary shaft;
The said thrust bearing apparatus is a thrust bearing apparatus of any one of Claim 1 thru | or 6, The steam turbine characterized by the above-mentioned. A method of supplying lubricating oil to a thrust bearing device that receives an axial load of the rotating shaft through a thrust collar installed on the outer peripheral side of the rotating shaft and fixed to a bearing base,
Formed on the inner peripheral side of the pad surface by recirculating high temperature lubricating oil flowing out from the pad surface to the inner peripheral side where the oil film temperature rises upstream of the plurality of pad surfaces facing the thrust collar in the axial direction is small The lubricating oil is supplied from the formed oil groove, and on the outer peripheral side where the temperature rise upstream of the pad surface is large, the low temperature lubricating oil from the outside is formed on the outer peripheral side upstream of the pad surface. A lubricating oil supply method for a thrust bearing device, characterized in that the lubricating oil is supplied from a portion.

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