JPS60101315A - Thrust bearing - Google Patents

Abstract

PURPOSE:To have a uniform oil film in a thrust bearing device, in which sector- shaped bearing shoes of split type arranged concentrically with a rotary shaft are supported by supports swingably, by specifying the radius of the supporting point of each shoe, and thereby reducing the inclination of the shoe in its radial direction. CONSTITUTION:A thrust bearing device to be used in a hydraulic power generator is in slide contact with a runner installed on a rotary shaft. Sector-shaped bearing shoes 4 of split type are arranged concentrically with the rotary shaft. Each shoe 4 is fixed swingably to a fixed member through a pivot 9 of support at a disc-shaped support 10 fixed to the undersurface of the shoe 4. The radius Rs of the supporting point P supported by pivot 9 of bearing shoe 4 shall be greater than 0.52R2+0.48R1 and smaller than 4/3.(R2<3>-R1<3>)/(R2<2>- R1<2>).180sin(theta/ 2)/pitheta, where R1 and R2 represent the inner and outer radii of the bearing shoe 4, respectively, and theta the angle. Thereby the intended purpose is accomplished.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a thrust bearing device, and in particular, to a thrust bearing device in which split fan-shaped bearing shoes arranged concentrically around a rotating shaft are swingable on a support. This article relates to the thrust bearing device supported by the

[Background of the invention]

1 and 2 show conventional examples of thrust bearing devices used in water turbine generators and the like. As shown in the figure, the thrust bearing device includes a runner 3 that is fixed to the rotating shaft 1 via a collar 2 and rotates together with the rotating shaft 1.
A bearing shoe 4 that is in sliding contact with the nona-3 and is arranged concentrically around the rotation axis l, and a floor 7 at the bottom of a bearing oil tank 6 that supports this bearing shoe 4 and has an oil cooler 5. It is composed of multiple supports 8 and the like fixed with bolts and the like.

The bearing shoe 4 is swingably supported around a pivot 9 of the support 8 so as to be tiltable in all directions. In the figure, 10 is a disk-shaped support.

In the thrust bearing device configured in this way, the position of the support point of the bearing shoe 4 has a great influence on the bearing performance. Center in the circumferential direction, l: A so-called eccentric support system in which the runner is slightly shifted in the rotational direction is usually used, and the runner 3
Even if the bearing shoe 4 rotates slightly, the bearing shoe 4 immediately tilts, forming a wedge-shaped oil film between the bearing shoe 4 and the runner 3 to form a stable oil film, and pumping water that rotates in both directions. A release for the awakening place! In so-called bidirectional rotating machines such as electric motors, the bearing shoe 4 is generally supported at the center in the circumferential direction, but as a matter of course, the ability to form an oil film is reduced, so when the electric machine starts or stops, the bearing High-pressure oil is forcibly supplied to the sliding surface of the shoe 4 to form an oil film to prevent damage to the sliding surface due to metal contact.

On the other hand, regarding the radial support point of the bearing shoe 4, conventionally the radial center position of the bearing shoe 4 (in this case The inner radius of the bearing shoe 4 up to the inner diameter M is R
1 + outer diameter N) was supported as a support point (fulcrum) P, but in this case, the bearing shoe 4 was tilted too much towards the outer diameter side, and as shown in the oil film pressure distribution curve indicated by the dotted line in the figure, The oil film on the inner diameter M side of the bearing shoe 4 becomes thinner, and the oil film pressure increases with the inner diameter M.
The sides are raised. On the other hand, if the support point P is moved extremely toward the outer diameter N side of the bearing shoe 4 as shown in FIG. 4, the outer diameter of the bearing shoe 4 will be The oil film on the N side becomes extremely thin, and the oil film pressure becomes higher on the outer diameter N side.

Among these, in the case of FIG. 3 mentioned above, the bearing shoe 4's support point P, angle θ, inner radius "1 + outer radius EL, diameter Rs of I support point P, area SI on the inner diameter side + area S2 on the outer diameter side.
Radial length B and length B1 from the inner diameter side to the support point P trench
The explanation will be as follows with reference to FIG. 5 in which the 1st class is shown. Radius Rs to support point P, area S on the inner diameter side
l + area St on the outer diameter side and surface on the inner diameter side! The ratios of x, SL and the area S2 on the outer diameter side are respectively as follows: (4) However, taking a 300 MVA class water turbine generator as an example, the bearing shoes can be calculated using equation (4). 4 inner radius R1 = 60cm
By substituting v outer radius R*=160 m and making a trial calculation, we get: Since the area s2 on the outer diameter side of the bearing shoe 4 is extremely large at 1.59 times the area 81 on the inner diameter side, the bearing shoe 4
is inclined toward the outer diameter side. Although it is desirable for the bearing shoe 4 to tilt in the circumferential direction and generate a wedge-shaped oil film,
It is desirable that the bearing is not tilted in the radial direction, and as described above, if it is tilted too much in the radial direction, the ability to generate an oil film will be reduced and a sufficient oil film will not be generated, leading to the risk of damage to the bearing.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is an object of the present invention to provide a thrust bearing device that can increase the ability to generate an oil film on the sliding surface between a bearing shoe and a runner.

[Summary of the invention]

That is, the present invention includes a runner that is fixed to a rotating shaft via a collar and rotates together with the rotating shaft, and a fan-shaped bearing shoe that is in sliding contact with the runner and is arranged concentrically around the rotating shaft. In a thrust bearing device, the thrust bearing device is provided with a support body disposed between the bearing shoe and the bottom of the bearing oil tank and having a pivot point Me, and in which the bearing shoe is supported so as to be swingable about the pivot of the support body. When the radius of the support point supported by the pivot of the shoe is Rg, the inner radius of the bearing shoe is RI + the outer radius is R2 + the angle is θ, the radius Rg of the support point is (0,521R2,
This allows the receiving shoe to be supported at a support point with reduced radial inclination.

In order to reduce the inclination of the bearing shoe, the fulcrum (support point) should be positioned in the radial direction of the bearing shoe.
We investigated the thrust bearing of a 0MVA class water turbine generator. The study results are shown in Figure 6, which shows that the inner radius R1 is 60c.
1n, the outer radius R3 is 160 brocades, and the angle θ is 22°. , that is, the radial fulcrum position ratio B s / B and 9
, the maximum oil film temperature and minimum oil film thickness between the bearing shoe and the runner are taken on the vertical axis, and the radial fulcrum position ratio B m
/B shows the relationship between maximum oil film temperature and minimum oil film thickness. As is clear from the maximum oil film temperature curve X and the minimum oil film thickness curve Y based on the radial fulcrum position ratio B m / B shown in the same figure, when the radial fulcrum position ratio B m / B is around 0.54, The minimum oil film thickness is the maximum and the maximum oil film temperature is the minimum. This is because the inclination of the bearing shoe in the radial direction becomes smaller, and the oil film on the sliding surface between the bearing shoe and the runner is formed uniformly and thickly from the inner diameter side to the outer diameter side. In comparison, this radial fulcrum position ratio B tr / B is 0.
50, that is, at the conventional support point, the minimum oil film thickness is reduced and the maximum oil film temperature is increased. Regarding these, the case where the radial fulcrum position ratio B s /B in FIG. 5 was changed was further studied. First, if we find the support point radius R8 where the inner diameter surface area S and the outer diameter surface area S2 are equal, we get (2
) E, n and Equation (3) > I T - S I = S 2, and the radial fulcrum position ratio B a / B in this case is 0.608, but the maximum oil film temperature and minimum oil film temperature in this case As for the thickness, as is clear from FIG. 6, the minimum oil film thickness is much smaller and the maximum oil film temperature is higher than that when the radial support point position ratio B tr /B is 0.54.

Next, when calculating the fulcrum of the center of gravity of the bearing shoe 4, the radius R8 at the center of gravity 1- of the bearing shoe 4 is 0.569 when the radial fulcrum position B s / B is subtracted from this. In this case as well, the minimum oil film thickness is lower than that when the radial fulcrum position ratio BII/B is 0.54.

The optimum support position in the radial direction from the viewpoint of bearing performance of these υ bearing shoes is the dimensional center position as shown in equation (1),
), and the geometric center of gravity position as in equation (6). Although it varies depending on the dimensions, it generally exists between formula (1) and formula (6), and the radial fulcrum position ratio B s / B
It has become clear that it is sufficient to make the value larger than 0.52. This radial direction fulcrum position ratio B th / B is B s
/B) The radius R8 of the support point supported by the pivot of the bearing shoe that satisfies the condition of 0.52 is Rs > (0
, 52R2 + 0.48 R1), so in the present invention, the radius of the support point supported by the pivot of the bearing shoe is EL.
m', s The inner radius of the receiving shoe is RI + the outer radius is FL2r When the angle is θ, the radius Ra of the support point is (0,52f
Lg +0,48R+) Made smaller than L. By doing so, it is possible to obtain a thrust bearing device that can increase the ability to generate an oil film on the sliding surface between the bearing shoe and the runner.

[Embodiments of the invention]

The present invention will be explained below based on the illustrated embodiments. An embodiment of the present invention is shown in FIGS. 7-9.

Note that parts that are the same as those in the conventional system are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, the radius of the support point P supported by the pivot 9 of the bearing shoe 4 is Ra, and the inner radius of the bearing shoe 4 is 1. When the outer radius is R2 + the angle is θ, the radius of the support point P is Rs e (0,52Rg +0.48 R+)
! It was bigger and bigger. By doing this, the bearing shoe 4 is supported at a support point with reduced radial inclination, making it possible to increase the ability to generate an oil film on the sliding surface between the bearing shoe 4 and the runner. A thrust bearing device can be obtained.

That is, by calculating the hydrodynamic center of gravity position of the oil film, the position of the support point P of the bearing shoe 4 is determined by the inner radius RI of the bearing shoe 4.
and the center of the outer radius R2, that is, the position on the outer diameter side (Bs+>Bz) of the equation (1), and on the inner diameter side than the geometric center of gravity position of the equation (6). By doing this, the difference B between the radius of the support point P of the bearing shoe 4 and the inner radius R1.

The radial fulcrum position ratio B g / B, which is the ratio of the radial length B of the bearing shoe 4 to In other words, the bearing shoe 4 is supported with a reduced inclination in the radial direction, and the thickness of the oil film generated on the sliding surface with the runner 3 increases from the inner diameter M side to the outer diameter side. It becomes uniform and increases over the N side, so that the bearing performance can be improved and the rotating electric machine can be operated safely.

〔Effect of the invention〕

As described above, the present invention can support a 1lllll bearing shoe with its radial inclination reduced, thereby making the oil film generated on the sliding surface between the bearing shoe and the runner uniform and increasing. Thus, it is possible to obtain a thrust bearing device that can increase the ability to generate an oil film on the sliding surface between the bearing shoe and the runner.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional side view of a conventional thrust bearing device -- a coin rolling machine, Fig. 2 is a longitudinal sectional side view of the circumference of a bearing shoe of a conventional thrust bearing device, and Fig. 3 is a longitudinal sectional side view of a conventional thrust bearing device. FIG. 4 is an explanatory diagram showing the state of oil film formation between the bearing shoe and the runner in another example of the conventional thrust bearing device;
Fig. 5 is an explanatory diagram showing the dimension symbols of the bearing shoe of the thrust bearing device, and Fig. 6 is a characteristic diagram showing the relationship between the radial fulcrum position ratio of the bearing shoe of the thrust bearing device, the minimum oil film thickness, and the maximum oil film temperature. , FIG. 7 is a partially enlarged view of a bearing shoe showing support for the bearing shoe in an embodiment of the thrust bearing device of the present invention;
Figure 8 is a plan view of the bearing shoe seen from the entry direction in Figure 7;
FIG. 9 is an explanatory diagram showing the state of oil film formation between the bearing shoe and the runner in one embodiment of the thrust bearing device of the present invention. 1...Rotation axis, 2...Color, 3...U/Na,
4...bearing shoe, 6...bearing oil tank, 7...bottom of bearing oil tank B 7th day 8↓

Claims (1)

[Claims] 1. A runner that is fixed to the rotating shaft via a collar and rotates together with the rotating shaft, and a fan-shaped bearing shoe that is in sliding contact with the runner and arranged concentrically around the rotating shaft. , a support disposed between the bearing shoe and the bottom of the bearing oil tank and having a pivot;
In a thrust bearing device in which the bearing shoe is swingably supported around a pivot of the support body, a radius of a support point of the bearing shoe supported by the pivot is defined as B.
S, the inner radius of the bearing shoe is RI + the outer radius is FL heat +
When the angle is θ, the radius FL s of the support point is (
A thrust bearing device characterized in that it is larger than 0.52ELs +0.48 a+).