JP2002021843A - Thrust bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thrust bearing device to be used for a rotary machinery hard to support the thrust of the rotary machinery with any one of a rolling bearing and a sliding bearing and requiring use of both the rolling and sliding bearings for the bearing of the rotary machinery. SOLUTION: In a thrust bearing device for a vertical rotary machinery for supporting a thrust load of a rotary shaft vertically supported freely to be rotated, a thrust collar 14 is provided in a rotary shaft 10, and a thrust sliding bearing 16 for supporting the thrust collar 14 freely to be slid and a thrust rolling bearing 18 for supporting the rotary shaft 10 by abutting on a lower end of the rotary shaft 10 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thrust bearing device for supporting a thrust load of a rotating machine.

[0002]

2. Description of the Related Art A conventional thrust bearing will be described below with reference to FIGS. 3, the rotating shaft 110 is rotatably supported by a pair of radial bearings 120 with respect to a stationary portion 120 such as a casing surrounding the rotating shaft 110. In the prior art illustrated, one end of the rotating shaft 110 supports the thrust load of the rotating shaft 110 only through the oil-lubricated thrust bearing 10 via the thrust collar 114, so that the thrust bearing 116 has to be enlarged. I can't get it.

In the prior art shown in FIG. 4, a thrust rolling bearing 118 is used instead of the oil lubricated thrust bearing 116 shown in FIG. In the prior art shown in FIG.
Thrust collar 114 only with thrust rolling bearing 118
Since the thrust load of the rotating shaft 110 is supported through
In particular, when the size of the rotary shaft 110 increases, the size of the thrust rolling bearing 118 also increases accordingly, so that the peripheral speed and heat generation increase, and the life of the thrust rolling bearing decreases.

In the conventional thrust bearing, (1) when starting and stopping and use are intermittent and a long life is not required (2) When a large thrust load is applied at a low rotational speed (3) Lubrication-related Thrust rolling bearings have been used when equipment (oil tanks, piping, pumps) needs to be miniaturized. On the other hand, thrust slide bearings have been used in high-speed rotating machines that require a long life and high reliability.

[0005]

In a horizontal rotating machine, the thrust bearing does not need to support the weight of the rotating shaft, and basically bears the thrust load due to the reaction force of the working fluid. It is possible to reduce the size by designing in consideration of such factors. However, in the case of a vertical rotary machine, it is necessary to support a thrust load based on the weight of the rotary shaft itself, in addition to the reaction force of the working fluid, which can be reduced by designing the machine. As a result, the thrust bearings of large vertical rotating machines and high-speed rotating machines are required to increase the thrust load at rest and increase the diameter of the thrust collar and increase the peripheral speed. Prevention is a major technical issue.

[0006] On the other hand, it is considered difficult to extend the life of a thrust rolling bearing due to a high peripheral speed. In addition, turbines used for hydroelectric power generation are required to have a load capacity of several hundred tons class.However, oil-lubricated thrust bearings, which are likely to leak oil due to environmental pollution, cannot be used. Although a water-lubricated thrust bearing is used, it is difficult to further increase the size due to the problem of centrifugal strength of the thrust collar 114.

[0007]

According to the present invention, there is provided a thrust bearing device for a vertical type rotary machine for supporting a thrust load of a rotating shaft vertically rotatably supported.
A thrust collar is provided on the rotating shaft, and a thrust sliding bearing that slidably supports the thrust collar and a thrust rolling bearing that contacts the lower end of the rotating shaft to support the rotating shaft are provided. The gist of the present invention is a thrust bearing device.

[0008] The thrust sliding bearing may be a fluid-lubricated thrust sliding bearing such as an oil-lubricated thrust bearing, a water-lubricated thrust bearing, a gas-lubricated thrust bearing, or a magnetic thrust bearing. Ceramic rolling bearing provided with the above rolling elements.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic longitudinal sectional view of a rotating shaft, for example, a bearing portion of a rotating shaft of a water turbine used for hydroelectric power generation. A rotating shaft 10 has a pair of radial bearings 12a and 12b at both ends thereof. Are rotatably supported with respect to the fixed portion 20.
The rotating shaft 10 includes the pair of radial bearings 12a and 12b.
On the other hand, FIG. 1 has an extended portion 10a extending outward beyond the lower radial bearing 12b. Extension 10
a is provided with a thrust collar 14 of a circular member extending in the radial direction, and the extension 10a also extends further outward from the thrust collar 14 to form an abutment 14a.

In the present embodiment, a fluid-lubricated thrust slide bearing, preferably an oil-lubricated thrust bearing 16, is provided between the thrust collar 14 and the stationary portion 20 as a thrust slide bearing. Oil-lubricated thrust bearing 16
There is no particular limitation on the bearing type, and a Kingsbury type or tapered land bearing can be used. The contact portion 14a
A thrust rolling bearing 18 such as a thrust ball bearing or a thrust roller bearing is disposed between the stationary part 20 and the stationary part 20.

In this embodiment, the oil-lubricated thrust bearing 16
The gap [delta] _s shown by the following expression. δ _s = α + δ _r where δr is the amount of axial compression deformation of the thrust rolling bearing 18 and is expressed by the following equation. δ _r = W / κ where, W: Thrust load (mainly the weight of the rotating shaft) κ: Static rigidity of the thrust rolling bearing δ _s is the minimum clearance (oil film thickness) α required depending on the type of oil-lubricated thrust bearing 16 By changing the value of を, an appropriate value can be obtained.

As described above, in the present embodiment, the rotating shaft 10
The oil-lubricated thrust bearing 16 is disposed at an appropriate position on the rotating shaft 10 in consideration of the allowable clearance at an equilibrium position in consideration of the compression deformation of the thrust rolling bearing 18 at rest. Accordingly, as the rotation of the rotating shaft 10 increases, the load capacity of the hydraulic lubricating thrust bearing 16 improves due to the dynamic pressure on the load surface of the hydraulic lubricating thrust bearing 16, and the thrust rolling bearing 18 accordingly increases the rotating shaft As a result, a favorable result was obtained in that the increase in the rotation speed and the increase in the peripheral speed reduced the shared load in a situation that was disadvantageous for extending the life. In addition, even when the rotation of the rotary shaft 10 is low and the load capacity due to dynamic pressure is small, the oil-lubricated thrust bearing 16 has a minimum clearance required at the time of initial setting, so that there is no damage.

In the present embodiment, in particular, the thrust rolling bearing 18 is selected so as to be able to support the load when the rotating shaft 1 is at rest, so that the oil-lubricated thrust bearing 16 is capable of supporting the thrust load when the rotating shaft 10 is stopped. , And in a region where design conditions at low speed become severe, most of the thrust load can be borne by the thrust rolling bearing 18. On the other hand, the rotating shaft 10
When the motor rotates at high speed, the thrust load capacity of the fluid lubricated thrust bearing 16 is generated as the rotation increases, so that the load on the thrust rolling bearing 18 is reduced. Therefore, by combining the fluid-lubricated thrust bearing 16 and the thrust rolling bearing 18, it is possible to compensate for each other's defects according to the rotation speed region of the rotating shaft 10.

In the first embodiment, the fluid-lubricated thrust slide bearing is formed by the oil-lubricated thrust bearing 16, but the present invention is not limited to this. Second embodiment of the present invention
In the embodiment, the fluid-lubricated thrust slide bearing includes:
It is formed of a water-lubricated thrust bearing. In this case, the thrust rolling bearing 18 is preferably a ceramic last rolling bearing having a ceramic rolling element.
This configuration is suitable especially when a vertical fluid machine using water as a working fluid such as a water turbine cannot be used when an oil-lubricated thrust bearing, in which an oil leak is feared due to environmental pollution, cannot be used. I have.

Further, since the viscosity of water is smaller than that of oil, the water-lubricated thrust bearing has a smaller load capacity than the oil-lubricated thrust bearing. Therefore, in the past, it was necessary to increase the pressure receiving area of the water-lubricated thrust bearing,
There was a problem that the bearing shape became complicated. In this embodiment,
In order to ensure the same load capacity as the oil-lubricated thrust bearing, the water-lubricated thrust bearing 16 can be combined with a hydrostatic thrust bearing as well as a hydrostatic thrust bearing.
The required load capacity is obtained by increasing the load capacity.

Furthermore, the fluid lubricated thrust slide bearing 1
6 is not limited to the oil or water lubrication described above.
In the third embodiment of the present invention, the fluid lubricated thrust slide bearing 16 is formed by a gas lubricated thrust bearing. However, gas, such as air, has a lower viscosity of the working fluid than oil and water, and has little load capability at low speed rotation. The centrifugal strength of the thrust collar 14, which becomes strict with the square of the number of revolutions, has to be a big problem, because the thrust bearing must be enlarged in size.

In this embodiment, the load of the rotating shaft 10 is supported by the thrust rolling bearing 18 in a region where the load capacity is low at a low speed and the load is applied to the gas lubricated thrust bearing 16 in a region where the rotation speed is high. The load on the rolling bearing 18 is reduced. As a result, the load of the thrust rolling bearing 18 decreases with an increase in the rotational speed.
8 can be reduced in size and lengthened. On the other hand, since the gas-lubricated thrust bearing 16 does not need to support a low-speed load, the gas-lubricated thrust bearing 16 can be significantly reduced in size as compared with a case where the thrust rolling bearing 18 is not used.

Next, a fourth embodiment of the present invention will be described with reference to FIG. Oil or water cannot be used for the rotating shaft 10 in a radioactive environment of nuclear facilities.
In the present embodiment, a magnetic thrust bearing 22 is used as the thrust slide bearing 16, and the magnetic thrust bearing 22 and the thrust rolling bearing 18 are used together to support the thrust load of the vertical rotary shaft 10. The weight of the rotating shaft 10 is the rotating shaft 1
The bearing is supported by a thrust rolling bearing 18 provided on the end face of the zero, and the radius clearance is appropriately set by the capacity described in the first embodiment. Therefore, in the present embodiment, the rotating shaft 10
The magnetic thrust bearing 22 was operated at an appropriate stage of the rotation increase. The magnetic thrust bearing 22 controls the current and the like while measuring the position of the number of rotations near the bearing, and controls the rotating shaft 1.
0 is maintained at the center of the bearing.

The load capacity fm of the magnetic thrust bearing 22 is expressed by the following equation.

(Equation 1) k: Electromagnetic attraction coefficient i: Current Z: Bearing clearance μ ₀ : Magnetic permeability N: Number of turns S: Iron core cross-sectional area

Generally, in order to increase the load capacity of the magnetic thrust bearing 22, (1) increase the current i (2) increase the number of turns N (3) increase the cross-sectional area S of the iron core (4) ) There is a method such as reducing the bearing clearance Z, but increasing the i increases the calorific value.
If S is increased, the size of the magnetic thrust bearing 22 increases, and Z cannot be reduced too much due to the problem of installation and assembly of the rotating shaft 10. Therefore, hitherto, the bearing size had to be large in a large vertical rotary machine, and the deformation of the thrust collar 14 and the securing of the centrifugal strength were serious problems. However, in the present embodiment, the thrust rolling bearing 18 provided on the end surface of the rotating shaft supports the weight of the rotating shaft itself, and the combined use of the magnetic thrust bearing 22 reduces the shared load of the thrust rolling bearing 18, thereby reducing the operating environment. Improvements have been made to extend the service life.

Further, the magnetic thrust bearing 22 does not need to have the ability to support the entire weight, and bears the load, so that the size can be reduced as compared with the case where the magnetic thrust bearing 22 is supported alone. Further, both the magnetic thrust bearing 22 and the thrust rolling bearing can be reduced in size and lengthened in life as compared with the case where they are individually supported.

In the above-described first to fourth embodiments, as the thrust rolling bearing 18, a ceramic last rolling bearing having a ceramic rolling element that does not use oil can be used. If an oil-lubricated thrust bearing, which is likely to leak due to a problem, cannot be used, it can be advantageously combined with a water-lubricated thrust bearing.

[0023]

According to the first aspect of the present invention, the rotating shaft of the vertical rotating body (machine) can be rotated via a pair of radial bearings and a thrust collar protruding from the rotating shaft. Since the supporting thrust bearing is composed of a thrust sliding bearing that slidably supports the thrust collar and a thrust rolling bearing that contacts the lower end of the rotating shaft and supports the rotating shaft, the size of the thrust bearing is reduced. , High peripheral speed and long life can be achieved.

According to the second aspect of the present invention, since the thrust slide bearing is a fluid-lubricated thrust slide bearing,
As the rotation of the rotating shaft increases, the thrust load is shared by the fluid lubricated thrust slide bearing, and the thrust load acting on the thrust rolling bearing is reduced. Therefore, the thrust rolling bearing may be designed to withstand the maximum thrust load (rotating shaft weight) when the rotating shaft is stopped, and the thrust rolling bearing is compared with the conventional heavy load, high peripheral speed thrust rolling bearing. Can be reduced.
As a result, the operating peripheral speed of the thrust rolling bearing can be minimized, and the life of the thrust rolling bearing can be extended, low heat generation and bearing loss can be minimized.

According to the third aspect of the present invention, since the thrust load is shared by the oil-lubricated thrust bearing in accordance with an increase in the rotation speed of the rotating shaft, the thrust load on the thrust rolling bearing is reduced by that much. In addition, by installing it at the end of the shaft that does not adversely affect the vibration characteristics of the shaft system even if the shaft diameter is reduced, it is possible to realize the technical problem of thrust rolling bearing, which is the technical problem of high load and high peripheral speed, and shortening the service life. Was. On the other hand, oil-lubricated thrust bearings also do not need to bear the thrust load in all rotational speed ranges, so the bearing size can be reduced, and the problem of securing the strength of the thrust collar, which is the biggest technical issue of increasing the capacity, is solved. At the same time, bearing damping, which is a drawback of the thrust rolling bearing, can be increased, so that the vibration damping performance of longitudinal vibration can be improved.

According to the fourth aspect of the present invention, since the thrust slide bearing is formed of a water-lubricated thrust bearing, the oil-lubricated thrust bearing, in which an oil leak is feared due to environmental pollution, cannot be used. Advantageously, the present invention can be applied.

According to the fifth aspect of the present invention, the fluid-lubricated thrust sliding bearing is formed of a gas-lubricated thrust bearing. However, since the gas-lubricated thrust bearing does not need to support a low-speed load, thrust rolling is not required. The gas-lubricated thrust bearing can be significantly reduced in size as compared with a case where no bearing is used.

According to the sixth aspect of the present invention, since the thrust slide bearing is formed of a magnetic thrust bearing, the load on the thrust rolling bearing can be reduced by the load capacity of the magnetic thrust bearing. . As a result,
By optimizing both types of bearings, a thrust bearing with a capacity that was not previously possible can be realized. Since the thrust rolling bearing according to the present invention is disposed at the shaft end, the size can be reduced without being restricted by the bending rigidity of the shaft, which greatly affects the bending vibration characteristics of the rotating shaft.

According to the present invention, since the thrust rolling bearing is made of a ceramic thrust rolling bearing, the thrust rolling bearing is excellent in temperature resistance. A thrust rolling bearing portion where a bearing cannot be used, for example, a water turbine used for hydroelectric power generation, can be used as a huge thrust rolling bearing having a load capacity of several hundred tons class.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a thrust bearing device according to a preferred embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a thrust bearing device according to another embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a conventional thrust bearing.

FIG. 4 is a longitudinal sectional view of another conventional thrust bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Rotating shaft 12a ... Radial bearing 12b ... Radial bearing 14 ... Thrust collar 16 ... Fluid lubrication type thrust sliding bearing 22 ... Magnetic thrust bearing

 ──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Seiya Yamada 1-1, Akunouramachi, Nagasaki-shi, Nagasaki F-term in Nagasaki Shipyard, Mitsubishi Heavy Industries, Ltd. 3J011 AA04 JA02 KA03 NA02 3J101 AA01 AA53 AA62 AA72 AA83 BA10 EA41 FA31 GA24 GA28 3J102 AA01 CA04 CA13 GA13

Claims (7)

[Claims] 1. A thrust bearing device for a vertical rotating machine that supports a thrust load of a rotating shaft vertically rotatably supported, wherein a thrust collar is provided on the rotating shaft, and the thrust collar is slidably supported. A thrust bearing device, comprising: a thrust slide bearing; and a thrust rolling bearing that abuts on a lower end of the rotating shaft to support the rotating shaft. 2. The thrust bearing device according to claim 1, wherein the thrust slide bearing comprises a fluid-lubricated thrust slide bearing. 3. The thrust bearing device according to claim 2, wherein the fluid-lubricated thrust slide bearing is an oil-lubricated thrust bearing. 4. The thrust bearing device according to claim 2, wherein the fluid-lubricated thrust slide bearing is a water-lubricated thrust bearing. 5. The thrust bearing device according to claim 2, wherein the fluid-lubricated thrust slide bearing is a gas-lubricated thrust bearing. 6. The thrust bearing device according to claim 1, wherein the thrust slide bearing is a magnetic thrust bearing. 7. The thrust rolling bearing according to claim 1, wherein said thrust rolling bearing comprises a ceramic thrust rolling bearing.
7. The thrust bearing device according to any one of claims 1 to 6.