JP2017141882A - Tilting pad journal bearing device and electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress vibrations of a rotary shaft.SOLUTION: A tilting pad journal bearing device comprises a rotary shaft, multiple bearing pads and a bearing housing supporting the multiple bearing pads, forms a lubricant film between the rotary shaft and the multiple bearing pads and supports the rotary shaft by the lubricant film. The tilting pad journal bearing device is characterized in that a supply part is provided for supplying a lubricant in a clearance between the rotary shaft and the bearing pad, and that a lubricant supply amount to a bearing pad positioned adjacently to a most loaded bearing pad that is a bearing pad with a greatest load of the supported rotary shaft among the bearing pads at a back flow side in a rotation direction of the rotary shaft is more than oil supply amounts to the other bearing pads.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tilting pad journal bearing device for supporting a rotating shaft.

  In a rotating machine operated at a high speed, a tilting pad journal bearing device is used. FIG. 7 is a cross-sectional view including a shaft showing a conventional tilting pad journal bearing device. The tilting pad journal bearing device includes a plurality of bearing pads 2 (2a to 2e) arranged in the circumferential direction on the outer periphery of the rotating shaft 1, a pivot 3 fixed to each back surface of the bearing pad, and a pivot 3 The bearing housing 4 that supports the bearing pads 2 via the bearing pads, and the oil supply device for supplying the lubricating oil to the bearing pads 2. The lubricating oil supplied from the oil tank 5 flows through the main oil supply pipe 6 to the circumferential groove 7 provided on the outer peripheral side of the bearing housing 4. The lubricating oil flowing in the circumferential groove 7 is distributed to the bearing pads 2 by the oil supply pipe 8. The distributed lubricating oil flows into each oil supply nozzle 9 (oil supply groove), and is discharged directly from the oil supply hole 10 provided in the oil supply nozzle 9 into the gap 11 between the rotary shaft 1 and each bearing pad 2. The oil film 12 shown in FIG. 8 is formed, and the rotary shaft 1 is supported by the pressure of the oil film 12. FIG. 7 shows an example of a type (Load on Pad: LOP) in which the load of the rotating shaft 1 is mainly supported by one bearing pad 2. The load of the rotating shaft 1 is mainly divided into two sheets. Some types are supported by the bearing pad 2 (Load between Pad: LBP).

  Lubricating oil supply methods can be roughly divided into two. One is an oil bath method in which the bearing housing is filled with lubricating oil and the bearing sliding surface is immersed in the lubricating oil. The other is a direct lubrication system shown in FIG. 7 in which lubricating oil is directly supplied to the gap 11 between the rotating shaft 1 and the bearing pad 2.

  In the direct lubrication system, the bearing housing 4 is not filled with lubricating oil, so that the stirring loss of the lubricating oil is small. Further, since the lubricating oil cooled from the front in the circumferential direction of each bearing pad 2 can be directly supplied, there is an advantage that the temperature of the bearing pad 2 can be relatively lowered.

  In recent years, the direct lubrication type tilting pad journal bearing device has been required to further reduce the loss, and therefore the amount of oil supply has been reduced. Patent Documents 1 and 2 describe examples in which the distribution of the oil supply amount to each bearing pad is adjusted in order to obtain the same or better bearing characteristics even when the oil supply amount is reduced.

  Patent Document 1 describes a structure in which a load sensor is attached between a pivot that supports each bearing pad in a tilting manner and a bearing housing, and the amount of oil supplied to each bearing pad can be adjusted during operation. As a result, it is possible to apply an appropriate amount of lubricating oil to each pad based on load data applied to each bearing pad during operation.

  Patent Document 2 describes a structure in which a temperature sensor is attached to each bearing pad, and the amount of oil supplied to each bearing pad can be adjusted during operation. As a result, it is possible to apply an appropriate amount of lubricating oil to each pad based on the temperature data of each bearing pad during operation.

JP 2002-147455 A JP 2003-120675 A

  By the way, when the oil supply amount is reduced, a starve region that cannot fill the gap between the rotary shaft and each bearing pad is formed by the oil amount distributed to each bearing pad. The stave region is an unstable state that repeats formation and collapse, and the oil film pressure fluctuates. If the fluctuation is large, the rotating shaft may be vibrated.

Generation of the starve region 13 will be described with reference to FIGS. FIG. 8 is an enlarged cross-sectional view of a shaft including an oil film when a starve region is formed in a conventional tilting pad journal bearing device. The amount of oil entering each bearing pad 2 is the amount of oil Q _sup supplied from an oil supply nozzle 9 (oil supply groove) provided in the circumferential front of the bearing pad 2 and upstream of the bearing pad 2 in the rotational direction. This is the sum of the amount of oil Q _carry (carry over) from the bearing pad 2 'located. When the added value is equal to or less than the oil amount _Qfill necessary to fill the gap 11 between the bearing pad 2 and the rotary shaft 1, the stave region 13 is formed.

FIG. 9 compares the relationship between the amount of oil supplied to each bearing pad and carryover in the conventional tilting pad journal bearing device with the amount of oil required to fill the gap between each bearing pad and the rotating shaft. FIG. The bearing pad 2 _satisfying Q _sup + Q _carry <Q _fill is in the rotational direction with respect to the bearing pads 2d and 2e positioned on the upper side in the vertical direction with respect to the rotating shaft 1 and the bearing pad 2b that most supports the load of the rotating shaft. This is a bearing pad 2c located on the downstream side. The bearing pads 2d and 2e have a large gap because the rotating shaft 1 is decentered in the axial load direction. As a result, the Q _fill is large, so that stave is likely to occur. On the other hand, the bearing pad 2c has a small gap 11 of the bearing pad 2b that most supports the load of the rotary shaft positioned on the upstream side in the rotational direction, so that the Q _carry from the pad 2b is reduced and the load of the rotary shaft is also compared. Therefore, the oil amount Q _fill becomes relatively large, and stave is likely to occur. 7 to 9 described above are LOP targets of five bearing pads, but the number of bearing pads is not necessarily the number, and the tendency is the same in LBP.

  Next, the formation of the starve region 13 and the vibration of the rotating shaft 1 will be described.

  FIG. 10 is a distribution diagram of oil film pressure generated in each conventional bearing pad. The oil film pressure of the bearing pads 2a, 2b and 2c positioned vertically downward with respect to the rotating shaft 1 is large. On the other hand, the oil film pressure of the bearing pads 2d and 2e located on the upper side in the vertical direction with respect to the rotating shaft 1 is small. For this reason, even if the stave region 13 is generated in the bearing pads 2d and 2e, the amplitude of the pressure fluctuation itself does not increase, so the possibility of vibrating the rotating shaft 1 is low. On the other hand, since the oil film pressure of the bearing pad 2c is large, when the stave region 13 is formed in the bearing pad 2c, the pressure fluctuation amplitude becomes large and the possibility of vibrating the rotating shaft 1 is high.

  However, the configuration of the tilting pad journal bearing device described in Patent Document 1 and Patent Document 2 can adjust and control the amount of oil supply based on the load and temperature information applied to each bearing pad during operation. There is no disclosure regarding adjusting and controlling the amount of oil supply in consideration of the occurrence of the stave region as described above. In addition, there is a problem that many sensors and adjustment / control functions are required.

  An object of the present invention is to suppress vibration of the rotating shaft.

  In order to solve the above-mentioned problem, for example, a lubricant film is formed between the rotating shaft, the plurality of bearing pads, the bearing housing that supports the plurality of bearing pads, and the rotating shaft and the plurality of bearing pads. In a tilting pad journal bearing device that supports a rotating shaft by a film, a supply portion that supplies a lubricant to a gap between the rotating shaft and the bearing pad is provided, and the bearing that has the largest load on the rotating shaft that is supported among the bearing pads is provided. It is characterized in that the amount of lubricant supplied to the bearing pad located adjacent to the downstream side in the rotational direction of the rotating shaft is larger than the amount of oil supplied to other bearing pads with respect to the most loaded bearing pad as the pad. And

  According to the present invention, even when the amount of oil supplied to the entire bearing is reduced, since the starve region is not formed in the bearing pad having a large oil film pressure, vibration of the rotating shaft can be suppressed.

It is a shaft-containing sectional view showing the tilting pad journal bearing device according to the first embodiment of the present invention. FIG. 2 is a circumferential development when cut along A-A ′ in FIG. 1. FIG. 6 is a diagram comparing the relationship between the amount of oil distributed to each bearing pad and carryover when using the first embodiment of the present invention with the amount of oil required to fill the gap between each bearing pad and the rotating shaft. is there. The shaft-containing cross-sectional enlarged view showing the oil film state of the bearing pad located on the downstream side in the rotational direction with respect to the bearing pad that supports the most load of the tilting pad journal bearing device according to the first embodiment of the present invention. It is. FIG. 6 is a circumferential development view of the tilting pad journal bearing device according to the second embodiment of the present invention when cut by A-A ′ in FIG. 1. The oil film area | region and starve area | region supplied with respect to the oil supply hole 10c and the bearing pad 2c in Example 1 are shown. The oil film area | region supplied with respect to the oil supply hole 10c and the bearing pad 2c in Example 2 is shown. It is a shaft-containing sectional view showing a conventional tilting pad journal bearing device. In the conventional tilting pad journal bearing apparatus, it is an axial cross-sectional enlarged view which showed the oil film state when a starve area | region was formed. It is the figure which compared the oil quantity required in order to fill the clearance gap between each bearing pad and a rotating shaft about the relationship between the distribution oil supply amount to each bearing pad, and a carry over in the conventional tilting pad journal bearing apparatus. It is a distribution map of the oil film pressure which generate | occur | produces in each conventional bearing pad.

  Hereinafter, the tilting pad journal bearing device according to the present embodiment will be described with reference to the drawings. In the following embodiments, a case where oil is used as a lubricant that fills the gap between the bearing pad and the rotating shaft will be described as an example, but the lubricant may be water or the like.

  The tilting pad journal bearing device of the first embodiment will be described with reference to FIGS. 1 and 2.

  FIG. 1 is an axial cross-sectional view showing a tilting pad journal bearing device according to a first embodiment of the present invention. As shown in FIG. 1, in the tilting pad journal bearing device of the present embodiment, a plurality of bearing pads 2 (2 a to 2 e) are disposed on a rotating shaft 1. A pivot 3 having a curvature is attached to the back surface of each bearing pad 2. Each pivot 3 is in point, line, or surface contact with the bearing housing 4, and the bearing pad 2 is supported by the bearing housing 4 via the pivot 3. The bearing housing 4 is provided with a circumferential groove 7 for allowing the lubricating oil flowing from the oil tank 5 through the main oil supply pipe 6 to flow along the circumferential direction of the bearing housing 4. Further, in the bearing housing 4, oil supply pipes 8 (8 a to 8 d) for distributing lubricating oil from the circumferential grooves 7 to the oil supply nozzles 9 (9 a to 9 d) positioned forward in the circumferential direction with respect to the bearing pads 2. ) Is provided. An oil supply hole 10 is provided on the sliding surface side of the rotary shaft 1 and the bearing pad 2 of the oil supply nozzle 9, and the lubricating oil distributed by the oil supply pipe 8 is supplied to the oil supply nozzle 9. Thus, the ink is discharged directly onto the sliding surfaces of the rotating shaft 1 and the bearing pad 2.

  FIG. 2 is a developed view in the circumferential direction of the bearing device when cut along A-A ′ in FIG. 1. As shown in FIG. 2, an oil supply nozzle 9 that supplies lubricating oil to the bearing pad 2 c that is located on the downstream side in the rotational direction with respect to the bearing pad 2 b that supports the most load is provided with another oil supply nozzle 9. An oil supply hole 10 c larger than the hole 10 is provided.

Next, the effect of the present embodiment will be described with reference to FIG. FIG. 3 shows the relationship between the amount of oil distributed to each bearing pad and the carryover when the first embodiment of the present invention is used, and the amount of oil necessary to fill the gap between each bearing pad and the rotating shaft. It is the figure compared. The dispensing fuel oil amount Q _sup indicated by solid lines when using the first embodiment of the present invention, the distribution oil amount Q _sup indicated by the broken line shows the case of using the conventional configuration. As described above, when the oil supply amount is reduced, the bearing pads in which the starve region 13 is easily formed are the bearing pads 2d and 2e positioned on the upper side in the vertical direction with respect to the rotating shaft 1, and the bearing pad 2b that supports the load most. The bearing pad 2c is located on the downstream side in the rotational direction. Further, as shown in FIG. 10, with respect to the bearing pads 2d and 2e, since the generated oil film 12 has a small pressure, the rotating shaft 1 can be vibrated even if the pressure fluctuates in the situation where the stave is generated. The nature is small. On the other hand, since the bearing pad 2c supports a relatively large load of the rotary shaft 1, the pressure of the oil film 12 is large, and the pressure fluctuation when the stave region 13 is formed becomes large. Therefore, the possibility that the rotating shaft 1 is vibrated is high. Therefore, in this embodiment, the size of the oil supply hole 10c provided in the oil supply nozzle 9 for supplying the lubricating oil to the bearing pad 2c is made larger than the oil supply hole 10 provided in the other oil supply nozzles, and the main oil supply pipe 6 The amount of oil distributed from the bearing pad 2c to the bearing pad 2c is larger than that of the other bearing pads 2. Therefore, as shown in FIG. 3, part of the amount of oil supplied to the bearing pads other than the bearing pad 2c can be supplied to the bearing pad 2c. Even when the amount of oil supplied is reduced, Q _sup Since + Qc _arry > Q _fill , the formation of the starve region 13 in the bearing pad 2c can be suppressed, and the vibration of the rotating shaft 1 can be suppressed.

FIG. 4 is a perspective view showing an oil film state of a bearing pad located on the downstream side in the rotational direction with respect to the bearing pad that supports the most load in the tilting pad journal bearing device according to the first embodiment of the present invention. It is a cross-sectional enlarged view. In this embodiment, since Q _sup increases in the bearing pad 2c, Q _sup + Qc _arry > Q _fill is established, so that the formation of the starve region can be prevented.

  The tilting pad journal bearing device of the second embodiment will be described with reference to FIG.

  FIG. 5 is a developed view in the circumferential direction of the tilting pad journal bearing device according to the second embodiment of the present invention when cut along A-A ′ in FIG. 1. This embodiment is different from the first embodiment in that the number of oil supply holes 10c provided in the oil supply nozzle 9 is larger than the number of oil supply holes 10 provided in other oil supply nozzles and is distributed in the axial direction. Is a point.

  The effect of the configuration of the second embodiment will be described with reference to FIG.

  FIG. 6A shows an oil film region and a starve region supplied to the oil supply hole 10c and the bearing pad 2c in the first embodiment. FIG. 6B shows an oil film region supplied to the oil supply hole 10c and the bearing pad 2c in the second embodiment. In the case of Example 1 shown in FIG. 6 (A), the diameter of the oil supply hole 10c is large, and the amount of oil supply can be increased as compared with the other bearing pads 2, but there is only one oil supply hole 10c. Therefore, there is a distance for the lubricating oil to spread in the bearing width direction of the bearing pad 2c. Therefore, there is a possibility that the starve region 13 is formed in the circumferential entrance of the bearing pad 2 and in the vicinity of the end of the bearing pad 2 in the bearing width direction. On the other hand, in the second embodiment, the cross-sectional area of the oil supply holes of the first embodiment is maintained and the plurality of oil supply holes are distributed in the longitudinal direction of the rotary shaft 1, so that the bearing pad 2c has a bearing width direction. Thus, the lubricating oil can be supplied uniformly, and the formation of the starve region 13 in the vicinity of the circumferential inlet and the rotation shaft width end can be suppressed.

  That is, the amount of oil supplied to the bearing pad located on the downstream side in the rotation direction of the rotating shaft with respect to the most loaded bearing pad that supports the load of the rotating shaft most is larger than the amount of oil supplied to the other bearing pads. Therefore, the total cross-sectional area of the hole of the oil supply hole for supplying the lubricating oil to the bearing pad positioned on the downstream side in the rotation direction of the rotating shaft with respect to the maximum load bearing pad is Any configuration that is larger than the total cross-sectional area of the holes of the oil supply holes for supplying lubricating oil to the other bearing pads may be used.

1 Rotating shaft 2 Bearing pad
3 Pivot 4 Bearing housing 5 Oil tank 6 Main oil supply pipe 7 Circumferential groove 8 Oil supply pipe 9 Oil supply nozzle
10 Oil supply hole 11 Crevice 12 Oil film 13 Starve area

Claims (7)

A rotation shaft, a plurality of bearing pads, a bearing housing that supports the plurality of bearing pads, a lubricant film is formed between the rotation shaft and the plurality of bearing pads, and the rotation shaft is formed by the lubricant film. In the supporting tilting pad journal bearing device,
A supply unit for supplying a lubricant to the gap between the rotating shaft and the bearing pad is provided, and the load bearing pad that is the bearing pad with the largest load of the rotating shaft to be supported among the bearing pads is described above. A tilting pad journal bearing device characterized in that the amount of lubricant supplied to a bearing pad located adjacent to the downstream side in the rotational direction of the rotating shaft is larger than the amount of oil supplied to other bearing pads. The tilting pad journal bearing device according to claim 1,
The supply unit is a supply nozzle, and the supply nozzle is provided with a supply hole, and the supply hole is located adjacent to the most loaded bearing pad on the downstream side in the rotation direction of the rotary shaft. The total cross-sectional area of the hole of the supply hole for supplying the lubricant to the bearing pad is larger than the total cross-sectional area of the hole of the supply hole for supplying the lubricant to the other bearing pad. Tilting pad journal bearing device. The tilting pad journal bearing device according to claim 1,
The supply unit is a supply nozzle, and the supply nozzle is provided with a supply hole, and the supply hole is located adjacent to the most loaded bearing pad on the downstream side in the rotation direction of the rotary shaft. The cross-sectional area of the hole of the supply hole for supplying the lubricant to the bearing pad is larger than the cross-sectional area of the hole of the supply hole for supplying the lubricant to the other bearing pad. Tilting pad journal bearing device. In the tilting pad journal bearing device according to claim 1,
The number of the supply holes for supplying the lubricant to the bearing pads located on the downstream side in the rotation direction of the rotating shaft with respect to the most loaded bearing pad is for supplying the lubricant to the other bearing pads. The tilting pad journal bearing device has a larger number than the number of the supply holes. The tilting pad journal bearing device according to claim 4,
A plurality of supply holes provided for supplying a lubricant to a bearing pad located on the downstream side in the rotational direction of the rotary shaft with respect to the most loaded bearing pad are distributed in the bearing width direction of the bearing pad. A tilting pad journal bearing device. In the tilting pad journal bearing device according to any one of claims 1 to 5,
A supply hole for supplying a lubricant to the most loaded bearing pad is located adjacent to the wake side in the rotation direction of the rotating shaft with respect to the most loaded bearing pad,
A supply hole for supplying a lubricant to the bearing pad located adjacent to the downstream side in the rotational direction of the rotating shaft with respect to the most loaded bearing pad is provided in the rotational direction of the rotating shaft with respect to the bearing pad A tilting pad journal bearing device which is located adjacent to a flow side.   An electric motor comprising the tilting pad journal bearing device according to any one of claims 1 to 6.

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