JPS60129418A - Thrust bearing device - Google Patents

Abstract

PURPOSE:To enhance the capability of oil-film creation, in a water turbine generator, etc., by supporting bearing shoes with their radial inclinations being reduced, so that an oil film created on the side surface of each shoe is uniform and increased. CONSTITUTION:The support point P of each bearing shoe 4, that is, the rotating center of a support member 10, is set between the inner and outer diameter R1, R2 sections of the bearing shoe 4 so that it comes to a point on the outer diameter side, B1>B2, but on the inner diameter side of the geometrical center thereof. Thus, the ratio of radial support point position BS/B which is the ratio of the diameter BS which is a difference between the diameter RS at the support point P of the bearing shoe 4 and the diameter of the inner diameter R1, and the radial length B of the bearing shoe 4, is set at a value such that the maximum thickness of an oil film between the bearing shoe 4 and a runner 3 is made large, but the highest temperature of the oil film is made low. With this arrangement, the bearing shoe 4 is supported being reduced in its radial inclination, the thickness of an oil film created on the slide surface with respect to the runner 3 is made uniform and increased, ranging from the inner diameter side M to the outer diameter side N, thereby the performance of the bearing is made satisfactory.

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 swingably supported by a support. This relates to a supporting thrust bearing device.

[Background of the invention]

1 and 2 show conventional examples of thrust bearing devices used in water turbine generators and the like. It is shown in the same figure. As shown in the figure, the thrust bearing device is fixed to a rotating shaft 1 via a collar 2.

and a runner 3 that rotates together with the rotating shaft 1. A plurality of fan-shaped bearing shoes 4° that are in sliding contact with this runner 3 and arranged concentrically around the rotating shaft 1.
The bearing oil tank 6 supports a bearing oil tank 6 and has an oil cooler 5. This support body 8 is composed of a leaf spring 11 having two pivots 9a and gb that project upward at a predetermined distance and a cylindrical or spherical support member 10 that projects downward. It is arranged astride the bearing shoes 4a and 4b. The bearing shoe 4 is connected to the leaf spring 11 and the bipot 9 with the support member 10 of the support body 8 as a fulcrum.
so that it can tilt in any direction via a, 9b,
It is supported so that it can swing freely.

The position of the support point of the lower bearing shoe 4 of the thrust bearing device configured in this way greatly affects bearing performance. A so-called eccentric support system in which the runner 3 is slightly shifted in the direction of rotation from the center of rotation is normally used, and even if the runner 3 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. In so-called bidirectional rotating machines such as generator motors for pumped storage power plants that rotate in both directions, they are generally supported at the circumferential center of the bearing shoe 4, but this naturally reduces the ability to form an oil film. When the bearing shoe 4 is started or stopped, high-pressure oil is forcibly supplied to the sliding surface of the bearing shoe 4 to form an oil film to prevent damage caused by metal contact on the sliding surface.

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 bearing Inner radius knl to inner diameter M of shoe 4
- Outer half ring up to outer diameter N + R2 If the diameter is R2, -9-1 is the center position) was supported as the support point (fulcrum) P. In this case, the bearing is:
x-4 is tilted too much toward the outer diameter side, 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.The oil film pressure is higher on the inner diameter M side. On the other hand, if the supporting point P is extremely shifted 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.

For the case shown in Fig. 3 above, the dimension symbol of the bearing shoe 4 is the support point P, the angle θ, the inner radius R1 - the outer radius R2 - the flat diameter of the support point P R@b, the area on the inner diameter side 8t - the outer diameter side area Sz - radial length B and support point P from the inner diameter side
The explanation will be as follows with reference to FIG. 5, which shows the length B[, etc. The radius Rih to the support point P, the inner diameter area Sm, the area St on the outer diameter side, and the area S on the inner and rear sides.

and the area S2 on the outer diameter side are respectively Rg ” 2 (R1+R2) ・・・7
-! (,1)゛・・・・・・ (4) However, using a 300 MVA class water turbine generator as an example, the inner radius of the bearing shoe 4 Rs = 60t in equation (4).
By substituting yn - outer radius R111 = 160 cm'fr, the trial calculation becomes, and since the area S2 on the outer diameter side of the bearing shoe 4 is extremely large at 1.59 times the area St on the inner diameter side, the bearing shoe 4
is inclined toward the outer diameter N side. It is desirable for the bearing shoe 4 to tilt in the circumferential direction and generate a wedge-shaped oil film, but it is desirable that the bearing shoe 4 not tilt in the radial direction, and as mentioned above, if it tilts too much in the radial direction, the ability to generate an oil film will be reduced. There was a risk that a sufficient oil film would not be generated and the bearings would be damaged.

[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 provides a runner that is fixed to a rotating shaft via a collar and rotates together with the rotating shaft.

A plurality of fan-shaped bearing shoes are in sliding contact with the runner and are arranged concentrically around the rotating shaft; A support body composed of a leaf spring having two pivots protruding from each other at a distance and a cylindrical or spherical support member protruding downward, and the leaf spring is disposed astride the adjacent bearing shoe. In the thrust bearing device, the bearing shaft is swingably supported via the leaf spring and the pivot with the support member as a fulcrum, the distance from the rotation axis of the support member being When R[+, the inner radius of the bearing shoe is &- the outer radius R2- the angle is θ, the distance Ra from the rotational axis of the support member is (0,'52Ri+), so that the bearing shoe is It is now supported at a support point where the radial tilt is reduced.

300 MVA
The thrust bearings of class water turbine generators were investigated. The study results are shown in Figure 6, which shows that the inner radius is 60 cm and the outer radius is 16 cm.
0cW1 - The performance calculation results of a bearing shoe with an angle of 22° are shown on the horizontal axis, and the difference between the radius Rs of the support point and the inner radius R1 is 13g.
and the radial length B of the bearing shoe, that is, the radial fulcrum position ratio Bs'/B, and the maximum oil film temperature and minimum oil film thickness between the bearing shoe and the runner on the vertical axis. This is what is shown. As is clear from the maximum oil film temperature curve The thickness is maximum and the maximum oil film temperature is 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 becomes uniform and large from the inner diameter side to the outer diameter side. In comparison, this radial fulcrum position ratio Bs/B is 0.50. That is, with conventional support points, the minimum oil film thickness is significantly reduced.

The maximum oil film temperature is high. Regarding these, please refer to the fifth
The case where the radial direction support position ratio Bs/B shown in the figure was changed was studied. First, if we find the support point radius Rs where the area S1 on the inner diameter side and the area S2 on the outer diameter side are equal, we get (2) and (
3) Since it is sufficient to write S5-8g in the formula, Rs ” 　(R: +
rn) "' (5) - In this case, the radial fulcrum position ratio Bg/B is 0.608. - As is clear from Figure 6, the maximum oil film temperature and minimum oil film thickness in this case are Compared to that when the directional fulcrum position ratio B s / B is 0.54, the minimum oil film thickness is considerably smaller and the maximum oil film temperature is higher.Next, when calculating the fulcrum at the center of gravity of the bearing shoe, The radius is gFi, and the minimum oil film thickness is lower than that when the radial support point position ratio Bs/B is 0.54.

From these, the optimal radial support position of the bearing shoe in terms of bearing performance is determined by the dimensional center position and (
Unlike the geometric center of area position as shown in equation 5) and the geometric center of gravity position as shown in equation (6), it is based on the hydrodynamic center of gravity position of the oil film, and the bearing shoe load per circumferential speed is It varies depending on the size and size. Roughly formula (1)! -(6
), and the radial and direction fulcrum position ratios Bs<
It is clear that B should be larger than 0.52. This radial direction fulcrum position ratio Bg/B is B day/B>
The radius R, s of the support point supported by the support member of the shaft and the receiving shoe satisfies the condition of 0.52.Rs>(0,5,2R
z+0.48Rt).

In the present invention, the distance from the rotation axis of the support member is set as follows, where the distance from the rotation axis of the support member is R8, the inner radius tRt of the bearing shoe - the outer radius R,z - the angle θ This makes it possible to obtain a thrust bearing device that can increase the ability to form 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 distance t'Rs from the rotation axis of the support member 100 - the inner radius of the bearing shoe 4 is R1, and the outer radius is R
1. When the angle is 0 (see Figure 5) K, support member 1
The rotation was made smaller than 0. 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 4 and the runner 3.

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 R1 of the bearing shoe 40.
and the center of the outer radius R2, that is, the outer radius side Bl>B! And make sure that it is on the inner diameter side than the geometric center of gravity position of equation (6). By doing this, the radial fulcrum position ratio Bs/B, which is the ratio of the difference Bs between the radius RI+ and the inner radius R1 of the support point P of the bearing shoe 4 and the radial length B of the bearing shoe 4, is 4
The minimum oil film thickness between the runner 3 and the runner 3 is large, and the maximum oil film temperature is small. 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 is reduced by the inner diameter M.
The radius increases uniformly and increases from the side to the outer diameter N side, and 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 enables the bearing shoe to be supported with a reduced radial inclination, thereby making it possible to uniformly and increase the oil film generated on the sliding surface between the bearing shoe and the runner. Therefore, 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 the drawing]

Figure 1 is a vertical side view of a conventional thrust bearing device, Figure 2 is a vertical side view of the area around the bearing shoe of a conventional thrust bearing device, and Figure 3 is a vertical side view of a conventional thrust bearing device.
The figure is an explanatory diagram showing the state of oil film formation between the bearing knee and runner of a conventional thrust bearing device, and Fig. 4 is an explanatory diagram showing the oil film formation between the bearing shoe and runner of another example of the conventional thrust bearing device. An explanatory diagram showing the situation, Fig. 5 is an explanatory diagram showing the dimension symbols of the bearing shoe of the thrust bearing device, and Fig. 6 is the relationship between the radial support position of the thrust bearing device, the minimum oil film thickness i, and the maximum oil film temperature. FIG. 7 is a plan view of the bearing shoe showing the support of the bearing shoe in one embodiment of the thrust bearing device of the present invention;
FIG. 8 is a partially enlarged view of the bearing shoe taken along line I-I in FIG. 7] FIG. 9 is an explanation 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 It is i. 1... Rotation axis, 2... Collar, 3... Runner,
4,4a. 4b, 4C, 4d... Bearing shoe, 6... Bearing oil tank, 7... Bottom (floor) of the bearing oil tank, 8... Support body 4.
9a. 9b... Pivot, 10... Support member, 11...
Leaf spring, P...support point. Agent Patent Attorney Akio Takahashi Ki 1 Kasumi 7m No - Mo 3 Fig. 4m M FN Condolence 6 Senkou Hikata Ichi fulcrum I iz ratio Bs/B Foil '70 B+ > 82 Mo 80 No Haku 9 (¥1

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 runner that is in sliding contact with the runner and is arranged concentrically around the rotating shaft. a plurality of fan-shaped bearing shoes; two pivots arranged between the bearing shoes and the bottom of the bearing oil tank and projecting upward at a predetermined distance; and a cylindrical or spherical pivot projecting downward. It is constructed with a leaf spring having a support member. a support body disposed astride the leaf spring and the adjacent shaft receiving shoe, and the bearing shoe is swingably supported via the leaf spring and the pivot using the support member as a fulcrum; The thrust bearing device is characterized in that the distance tRs from the rotational axis of the support member - the inner diameter t'Rt of the bearing shoe - the outer radius tRz is smaller than the support member when the angle is θ. Thrust bearing device ◎2 The thrust bearing device according to claim 1, wherein the two pivots are provided at bilaterally symmetrical positions opposite to the installation position of the support member.