JP2019157906A - Bearing device - Google Patents

Abstract

To minimize influence of damage, etc. of an elastic part of a squeeze film damper by gradually changing the rigidity of the elastic part.SOLUTION: A bearing device comprises: a bearing part for rotatably supporting a rotary shaft; a squeeze film damper provided on the outer peripheral side of the bearing part and having an inner ring 18 and an outer ring 20 opposing each other with an oil film forming gap G interposed therebetween; and a bridge part 22 connecting the inner ring 18 and the outer ring 20 to each other and causing the outer ring to elastically support the inner ring. A part of the bridge part 22 opposes the wall surface of the inner ring or of the outer ring via a slit St. The bridge part 22 is configured in such a manner that a contact area S between the external surface of the bridge part and the wall surface of the inner ring or of the outer ring increases in the range of less than Swith the increase in the displacement of the inner ring when the displacement of the inner ring reaches a prescribed value or more, where the Sdenotes the maximum contact area between the external surface of the bridge part 22 and the wall surface of the inner ring or of the outer ring at the maximum displacement of the inner ring 18.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a bearing device and a rotary machine including the bearing device.

In rotating machines such as compressors and steam turbines, stable support of the rotating shaft system is one of the problems. In order to solve this problem, it is effective to improve the support characteristics (attenuation, rigidity, etc.) of the bearing portion that supports the rotating shaft, and studies have been made from this viewpoint.
In Patent Document 1, when oil is supplied to a gap formed between an inner ring and an outer ring, and the rotary shaft vibrates and the gap is displaced, viscous incompressible oil passes through the gap. A squeeze film damper that exhibits the effect of attenuating the vibration of the rotating shaft by flowing is disclosed.
In addition, means has been proposed in which an elastic portion is interposed between the inner ring and the outer ring, thereby reducing the rigidity of the bearing portion and increasing the damping effect.

US Pat. No. 5,421,655

  In a squeeze film damper having an elastic part, when the elastic part is damaged due to external impact or aging, or when an excessive load is applied to the elastic part, the elastic part is collapsed all at once. Stiffness increases at a stretch. As a result, the support position of the rotating shaft supported by the bearing pad may change abruptly, which may cause a sudden change in the rotating shaft system.

  In one embodiment, when the elastic portion provided in the squeeze film damper is damaged, or when an excessive load is applied, the rigidity of the elastic portion is gradually changed to minimize the influence. Objective.

(1) A bearing device according to an embodiment
A bearing for rotatably supporting the rotating shaft;
A squeeze film damper provided on the outer peripheral side of the bearing portion and including an inner ring and an outer ring facing each other across at least one oil film formation gap;
A bridge portion that connects the inner ring and the outer ring and elastically supports the inner ring on the outer ring;
With
At least a part of the bridge portion faces the inner ring or the outer ring wall surface through a slit,
When the maximum contact area between the outer surface of the bridge portion and the wall surface at the time of maximum displacement of the inner ring is S _max , the bridge portion has the displacement of the inner ring equal to or greater than a specified value, As the displacement increases, the contact area S between the outer surface and the wall surface of the bridge portion increases within a range less than _Smax .

According to the configuration of (1) above, when the displacement of the inner ring is equal to or greater than the specified value, the bridge portion has a contact area S between the outer surface of the bridge portion and the inner ring or outer ring wall surface of less than S _max. Increase within the range. As a result, since the rigidity of the bridge portion is not increased suddenly, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(2) In one embodiment, in the configuration of (1),
The bridge portion is configured such that when the displacement of the inner ring becomes equal to or greater than a predetermined value, the contact area S increases stepwise as the displacement increases.
According to the configuration of (2) above, since the contact area S of the bridge portion increases stepwise, the rigidity of the bridge portion can be increased stepwise. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(3) In one embodiment, in the configuration of (2),
The slit has a plurality of regions with different sizes of gaps, and is configured such that the outer surface of the bridge portion and the wall surface come into contact in stages in the plurality of regions.
According to the configuration of (3) above, since the outer surface of the bridge portion and the wall surface of the inner ring or the outer ring contact stepwise in a plurality of regions, the rigidity of the bridge portion can be increased stepwise. it can. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(4) In one embodiment, in the configuration of (2),
The slit includes a first slit facing the wall surface of the inner ring and a second slit facing the wall surface of the outer ring,
The first slit and the second slit include a region having a gap having a different size.
According to the configuration of (4), when a load is applied to the bridge portion, the wall surfaces forming the slit in the region contact with a time difference, so that the rigidity of the bridge portion can be increased stepwise. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(5) In one embodiment, in the configuration of (1),
The bridge portion is configured such that the contact area S continuously increases as the displacement increases.
According to the configuration of (5) above, the bridge portion can continuously increase the rigidity of the bridge portion because the contact area S continuously increases as the inner ring displacement increases. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(6) In one embodiment, in the configuration of (5),
In at least a part of the bridge portion, the slit is configured such that the size of the gap is continuously different, and the outer surface of the bridge portion and the wall surface are continuously contacted in the gap. The
According to the configuration of (6) above, since the wall surfaces constituting the slits are in continuous contact, the rigidity of the bridge portion can be continuously increased. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(7) In one embodiment, in any one of the configurations (1) to (6),
The bridge portion has at least one bent portion.
According to the configuration of (7) above, since the bridge portion has at least one bent portion, the rigidity of the bridge portion can be reduced with respect to the load applied to the bridge portion from the rotating shaft via the inner ring. Further, since the bent portion has the bent portion, the bent portion is also formed in the slit, so that it becomes easy to form a region that can contact the slit stepwise or continuously.

(8) A bearing device according to an embodiment
A bearing for rotatably supporting the rotating shaft;
A squeeze film damper provided on the outer peripheral side of the bearing portion and including an inner ring and an outer ring facing each other across at least one oil film formation gap;
A bridge portion that connects the inner ring and the outer ring and elastically supports the inner ring on the outer ring;
With
At least a part of the bridge portion faces the inner ring or the outer ring wall surface through a slit,
The bridge portion includes at least one notch opening in the slit,
The total contact area of the first contact area between the outer surface of the bridge portion and the wall surface, and the second contact area between the outer surfaces of the bridge portions facing each other across the notch is S ′,
When the total contact area at the maximum displacement of the inner ring is S ′ _max ,
The bridge portion is configured such that when the displacement of the inner ring becomes equal to or greater than a predetermined value, the total contact area S ′ increases within a range less than S ′ _{max as the} displacement increases.

According to the configuration of (8) above, when the displacement of the inner ring becomes equal to or greater than the specified value, the bridge portion increases in the range where the total contact area S ′ is less than S ′ _{max as} the displacement increases. For this reason, the rigidity of the bridge portion is not rapidly increased. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(9) In one embodiment, in the configuration of (8),
The bridge portion is configured such that the contact area S increases stepwise as the displacement increases.
Since the bridge portion has the above-described notch, the contact timing can be made different between the notch and the other part of the slit as the displacement of the inner ring increases. Therefore, since the contact area S increases stepwise, the rigidity of the bridge portion is not rapidly increased. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(10) In one embodiment, in the configuration of (8) or (9),
The notch is formed in a portion where a compressive load of the bridge portion is applied when the inner ring is displaced.
According to the configuration of (10) above, the notch is formed at a site to which a compressive load is applied, so that the outer surfaces of the bridge portions facing each other across the notch can be brought into contact with each other by the compressive load. Further, by providing a time difference between the contact timing of the wall surface of the notch and the contact timing of the other part of the slit, it is possible to prevent the rigidity of the bridge portion from rapidly increasing. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

(11) In one embodiment, in the configuration of (10),
The bridge portion has at least one bent portion,
The notch is formed in the bent portion.
According to the configuration of (11) above, when a compressive load is applied to the bridge portion, the compressive load is applied to the bent portion. Since the notch is formed in a bent portion to which a compressive load is applied, the outer surfaces of the bridge portions facing each other across the notch can be brought into contact with each other by the compressive load.

(12) In one embodiment, in any one of the configurations (8) to (11),
The notch includes a plurality of notches having different gap sizes.
According to the configuration of (12), since the size of the gap differs between the plurality of notches, the contact area S can be increased stepwise by providing a time difference in the wall surface contact timing between the plurality of notches. Therefore, since the rigidity of the bridge portion can be increased stepwise, changes in the rotation axis position and various changes given to the rotation axis system can be made gentle.

(13) A rotating machine according to an embodiment includes:
A rotation axis;
A bearing device having any one of the constitutions (1) to (12);
Is provided.
According to the configuration of (13), since the bearing device having the above configuration is provided, it is possible to moderately change the rotation shaft position and various changes applied to the rotation shaft system.

  According to some embodiments, even when the squeeze film damper is damaged due to external impact or aging, or when an excessive load is applied from the rotating shaft, the rigidity of the bridge portion is not increased rapidly. The change of the rotation axis position and various changes given to the rotation axis system can be made gentle.

It is sectional drawing in alignment with the radial direction of the bearing apparatus which concerns on one Embodiment. It is sectional drawing which follows the axial direction of the bearing apparatus which concerns on one Embodiment. It is sectional drawing which follows the radial direction of the bridge part (non-contact area) concerning one embodiment. It is sectional drawing which follows the radial direction of the bridge part (contact area) which concerns on one Embodiment. It is sectional drawing which follows the radial direction of the bridge part which concerns on one Embodiment. It is sectional drawing in alignment with the one part radial direction of the bridge part which concerns on one Embodiment. It is a diagram which shows the relationship between the displacement of the inner ring in the bridge part which concerns on one Embodiment, and a contact area. It is a diagram which shows the relationship between the displacement of the inner ring in the bridge part which concerns on one Embodiment, and a contact area. It is a diagram which shows the relationship between the displacement of the inner ring in the bridge part which concerns on one Embodiment, and a contact area.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.
For example, expressions expressing relative or absolute arrangements such as “in a certain direction”, “along a certain direction”, “parallel”, “orthogonal”, “center”, “concentric” or “coaxial” are strictly In addition to such an arrangement, it is also possible to represent a state of relative displacement with an angle or a distance such that tolerance or the same function can be obtained.
In addition, for example, expressions representing shapes such as quadrangular shapes and cylindrical shapes not only represent shapes such as quadrangular shapes and cylindrical shapes in a strict geometric sense, but also within the range where the same effect can be obtained. A shape including a chamfered portion or the like is also expressed.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one constituent element are not exclusive expressions for excluding the existence of the other constituent elements.

1 and 2 show a bearing device 10 according to an embodiment.
1 and 2, the bearing device 10 includes a bearing portion 14 on the outer peripheral side of the rotating shaft 12 and a squeeze film damper 16 on the outer peripheral side of the bearing portion 14. The bearing part 14 supports the rotating shaft 12 rotatably. The squeeze film damper 16 includes an inner ring 18 and an outer ring 20 that face each other with the oil film formation gap G interposed therebetween. One or more oil film forming gaps G are formed in the circumferential direction of the rotating shaft 12 (hereinafter also simply referred to as “circumferential direction”). The rotating shaft 12 rotates around the central axis O.
1 indicates the radial direction of the rotary shaft 12 (hereinafter also referred to simply as “radial direction”), and the arrow a direction in FIG. 2 indicates the axial direction of the rotary shaft 12 (hereinafter simply referred to as “axial direction”). Say).

  An incompressible oil having viscosity is supplied to the oil film forming gap G from an oil supply unit (not shown). The inner ring 18 receives a load from the rotating shaft 12 and is displaced to the outer ring side, and changes the size of the oil film forming gap G to flow the oil. Thereby, an attenuation effect that attenuates the load applied from the rotating shaft 12 can be obtained. This damping effect suppresses vibrations of the rotating shaft system and enables stable support of the rotating shaft system. In addition, by adjusting the amount of oil flow, the oil film pressure in the oil film forming gap G is adjusted, whereby the damping performance can be adjusted.

ここで、Ｂ＝１２πμＬ（Ｒ／ｃ）^３、μ：油の粘性係数、Ｒ：ダンパ径、Ｌ：ダンパ幅、ｃ：径方向隙間の大きさ、ε：回転軸の偏心量である。
ε＝ｅ／ｃ＝１−δ_０／ｃ
ここで、ｅ：回転軸の偏心量、δ_０：回転軸の軸受からの浮上量である。
（１）式から、油膜形成隙間の面積が大きいほど油膜減衰常数Ｃψが大きくなり、かつ油膜減衰常数Ｃψは径方向隙間の大きさｃの３乗に比例することがわかる。従って、回転軸１２から軸受装置に付加される荷重が大きくなり、油膜形成隙間Ｇが狭くなると、油膜圧が増加し、油膜減衰常数Ｃψが増加して減衰効果が増す。 The oil film attenuation constant Cψ representing the attenuation effect exhibited by the oil film formation is obtained from the following equation (1).

Here, B = 12π μL (R / c) ³ , μ: viscosity coefficient of oil, R: damper diameter, L: damper width, c: size of radial gap, ε: eccentricity of rotating shaft.
ε = e / c = 1−δ ₀ / c
Here, e is the amount of eccentricity of the rotating shaft, and δ ₀ is the flying height of the rotating shaft from the bearing.
From equation (1), it can be seen that the larger the area of the oil film formation gap, the larger the oil film attenuation constant Cψ, and the oil film attenuation constant Cψ is proportional to the cube of the radial gap size c. Therefore, when the load applied to the bearing device from the rotary shaft 12 increases and the oil film formation gap G becomes narrow, the oil film pressure increases, the oil film attenuation constant Cψ increases, and the damping effect increases.

As shown in FIG. 3, the bearing device 10 further includes a bridge portion 22 that connects the inner ring 18 and the outer ring 20. The bridge portion 22 elastically supports the inner ring 18 on the outer ring 20. At least a part of the bridge portion 22 faces the wall surface 18a of the inner ring 18 or the wall surface 20a of the outer ring 20 through the slit St. The inner ring 18 receives a load L from the rotary shaft 12 and is displaced in the radial direction (arrow b direction) of the rotary shaft 12. FIG. 3 shows a state where an excessive load is not received from the rotating shaft 12 and the opposing wall surface forming the slit St is not in contact with any part.
FIG. 4 shows a state in which the outer surface 23b and the wall surface 18a which form the region R _S1 having the smallest gap width in the slit St upon receiving the load L from the rotating shaft 12 are in contact with each other. As the load L increases, other wall surfaces forming the slit St also start to contact.

The maximum contact area S of the contact area S between the outer surface 23a of the bridge portion 22 and the wall surface 20a of the outer ring 20 or the outer surface 23b of the bridge portion 22 and the wall surface 18a of the inner ring 18 when the inner ring 18 is displaced maximum is S. _When it is set to _max , when the displacement of the inner ring 18 becomes more than a specified value, the bridge portion 22 is configured such that the contact area S increases within a range less than S _{max as} the displacement of the inner ring 18 increases. Is done.
As described above, even when the bridge portion 22 is damaged due to external impact or aging deterioration, or even when an excessive load is applied to the bridge portion 22, the contact area S increases within the range of less than _Smax. The rigidity of the bridge portion 22 is not increased rapidly. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

In one embodiment, as shown in FIGS. 1 and 2, the bearing portion 14 includes a tilting pad 24. The tilting pad 24 is connected to the inner surface of the inner ring 18 through a pivot 25. The tilting pad 24 can tilt in any direction with the pivot 25 as a base point. The tilting pad 24 is formed with a lubricating oil passage (not shown) that opens to the inner surface, and the lubricating oil is supplied between the rotary shaft 12 and the tilting pad 24.
According to this embodiment, the rotating shaft 12 can be stably rotated by the seizure prevention effect by the oil film formed around the tilting pad 24.

  In another embodiment, the bearing portion 14 includes a rolling bearing. According to this embodiment, the squeeze film damper 16 having the above-described configuration is provided on the outer peripheral side of the bearing portion including the rolling bearing, and the rotating shaft can be supported by a combination thereof. As a result, due to the synergistic effect of the low friction support by the bearing portion including the rolling bearing and the damping effect of the squeeze film damper 16, damping of vibrations and the like generated in the rotating shaft system while ensuring the rigidity of the support side even at high speed rotation. An effect can be heightened and the rotating shaft 12 can be supported stably.

  In one embodiment, as shown in FIG. 2, in the bearing device 10, side plates 21 are provided on both axial end surfaces of the squeeze film damper 16. The side plate 21 forms an oil discharge path Pd that communicates with the oil film forming gap G between both end surfaces of the outer ring 20 in the axial direction. By discharging the oil from the oil discharge path Pd, the fluid state of the oil can be maintained in the oil film forming gap G, and thereby the load applied from the rotary shaft 12 can be attenuated. This damping effect suppresses vibrations of the rotating shaft system and enables stable support of the rotating shaft system. Further, by adjusting the amount of oil discharged from the oil discharge path Pd, the oil film pressure in the oil film forming gap G is adjusted, and thereby the damping performance can be adjusted.

  In one embodiment, as shown in FIG. 1, a plurality of bridge portions 22 are discretely provided in the circumferential direction between the inner ring 18 and the outer ring 20. By providing the bridge portion 22, the rigidity of the squeeze film damper 16 can be determined by the rigidity of the bridge portion 22. Accordingly, since the rigidity of the squeeze film damper 16 and the damping performance due to the formation of the oil film can be set independently, optimum settings can be made for each to enhance the damping effect of the squeeze film damper 16.

  In one embodiment, the bridge portion 22 is disposed so as to extend in the axial direction of the rotating shaft 12. By arranging the bridge portion 22, it is possible to exert a uniform elastic force in the axial direction of the rotary shaft 12, and to support the rotary shaft 12 with a uniform elastic force in the axial direction of the rotary shaft 12.

In one embodiment, the bridge portion 22 is configured such that when the displacement of the inner ring 18 becomes equal to or greater than a specified value, the contact area S increases stepwise as the displacement increases.
According to this embodiment, since the contact area S of the bridge portion 22 increases stepwise, the rigidity of the bridge portion 22 can be increased stepwise. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

In the embodiment, in the bridge portion 22 (22a) illustrated in FIG. 3, the slit St (St ₁ , St ₂ ) has a plurality of regions Rs1, Rs2 and other regions having different gap sizes. The outer surface 23a and the wall surface 20a of the bridge portion 22 and the outer surface 23b and the wall surface 18a are configured to contact in a stepwise manner in a plurality of regions having different gap sizes. As a result, the rigidity of the bridge portion 22 can be increased stepwise, so that changes in the rotation axis position and various changes applied to the rotation axis system can be made gradual.

In the embodiment shown in FIG. 3, the size of the gap between the slits St (St ₁ , St ₂ ) has the following relationship.
Region Rs1 <region Rs2 <other region (1)
When the load L applied from the rotating shaft 12 exceeds the non-contact area of the wall surface forming the slit St, first, the wall surface of the region Rs1 comes into contact. When the load L further increases, the wall surface of the region Rs2 comes into contact. Thereafter, when the load L further increases, other regions come into contact.
The rigidity when the wall surface of the region Rs1 is in contact is K (rear 1), the rigidity when the wall surface of the region Rs1 and the region Rs2 is in contact is K (rear 2), and when all the regions of the slit St are in contact If the stiffness is K (3 later), the following relationship holds.
K (back 1) <K (back 2) <K (back 3) (2)

FIG. 7 is a diagram showing the relationship between the displacement of the inner ring 18 and the contact area S in the bridge portion 22 (22a) shown in FIG. In the figure, d ₀ is a point where the opposing wall surface forming the slit St starts to contact. When the rigidity of the bridge portion 22 (22a) becomes K (rear 3), that is, when contact with the opposing wall surface occurs in the entire slit, the contact area S becomes the maximum contact area _Smax .

As described above, when the bridge portion 22 is damaged or when the load L applied to the inner ring 18 from the rotary shaft 12 becomes excessive, the rigidity of the bridge portion 22 increases stepwise. Various changes given to the rotating shaft system can be made gentle.
In addition, as a comparative example, when the size of the gap of the slit St is uniform, the rigidity of the bridge portion 22 increases abruptly. Therefore, the support position of the rotary shaft 12 supported by the pad or the like changes rapidly, and accordingly There is also a possibility of giving various rapid changes to the rotating shaft system.

In one embodiment, as shown in FIG. 3, the slit St includes a first slit St (St ₁ ) facing the wall surface 20 a of the outer ring 20 and a second slit St (St ₂ ) facing the wall surface 18 a of the inner ring 18. ). The first slit St (St ₁ ) and the second slit St (St ₂ ) include regions having gaps having different sizes.
According to this embodiment, when a load L is added from the rotation shaft 12 to the bridge portion 22, the wall surface constituting the slit _St (St 1, St ₂₎ having a gap of different sizes are brought into contact with a time difference. Accordingly, since the bridge portion 22 is gradually increased in rigidity in the process of increasing the contact area S, it is possible to moderate changes in the rotation axis position and various changes applied to the rotation axis system.

In one embodiment, the bridge portion 22 is configured such that the contact area S continuously increases as the displacement of the inner ring 18 increases when the displacement of the inner ring 18 exceeds a specified value.
According to this embodiment, the bridge portion 22 can continuously increase the rigidity of the bridge portion 22 because the contact area S continuously increases as the displacement of the inner ring 18 increases. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

In one embodiment, like the bridge portion 22 (22b) shown in FIG. 5, in at least a part of the bridge portion 22, the slit St is configured such that the size of the gap is continuously different.
In the embodiment shown in FIG. 5, a region R ₂ in which the size of the gap is continuously different is formed in a part of the wall surface 20 a of the outer ring 20 and a part of the outer surface 23 a of the slit St (St ₁ ). In the region R ₂ at the contact start point d ₀ since, configured wall surface forming a slit St is in continuous contact with the passage of time.
According to this embodiment, since the opposing wall surfaces forming the slit St (St ₁ ) in the region R ₂ are in continuous contact with time, the rigidity of the bridge portion 22 (22b) is continuously increased. . As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

In the embodiment shown in FIG. 5, in the radial cross section of the bearing device 10, a gradient (angle θ) is given to the outer surface 23 a at a part of the wall surface 20 a, and the slit St (St ₁ ) in the region R ₂ by this gradient. So that the gaps gradually widen.
Accordingly, when the contact start point d ₀ is exceeded, the wall surface 20a of the outer ring 20 and the outer surface 23a of the slit St (St ₁ ) are continuously formed with time as the load L increases in the region R _2. Therefore, the rigidity of the bridge portion 22 (22b) is continuously increased. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

FIG. 8 is a diagram showing the relationship between the displacement of the inner ring 18 and the contact area S in the embodiment shown in FIG. For a region other than the region R ₂ is a narrow gap of the slit St than the region R _2, once the wall contact in the region other than the region R ₂ occurs. Then occurs continuous contact from the gap is narrow regions in the region R _2, increases with a slope that is the contact area S. The shape of the gradient curve can be changed by appropriately selecting the shape of the gap of the slit St, as shown by the broken line in FIG.
Also in this embodiment, since the rigidity of the bridge portion 22 (22b) does not increase at a stretch and does not reach the maximum contact area _{Smax at} a stretch, the change of the rotation axis position and various changes given to the rotation axis system are moderated. be able to.

In one embodiment, as shown in FIGS. 3 to 5, the bridge portion 22 has at least one bent portion Be.
According to this embodiment, since the bridge portion 22 has at least one bent portion Be, the rigidity of the bridge portion 22 can be reduced with respect to the load applied to the bridge portion 22 from the rotary shaft 12 via the inner ring 18. . In addition, since the bridge portion 22 has the bent portion Be, the bent portion Be is also formed in the slit St, so that it becomes easy to form a region that can contact the slit St stepwise or continuously.

In one embodiment, the shape of the bent portion Be is constituted by, for example, a waveform or a zigzag cross section.
In one embodiment, the bridge portion 22 has one or more, preferably a plurality of bent portions Be, and extends along the radial direction. Thereby, the bridge part 22 can hold | maintain a big expansion-contraction force with respect to the load L added along the radial direction from the rotating shaft 12. FIG. Therefore, the range in which the rigidity of the bridge portion 22 can be adjusted can be expanded.

In one embodiment, as shown in FIG. 6, the bridge portion 22 (22 c) has at least one notch N (N ₁ , N ₂ ) that opens to the slit St. The total contact area of the first contact area between the outer surfaces 23a, 23b of the bridge portion 22 and the wall surfaces 18a, 20a and the second contact area between the outer surfaces of the bridge portion 22 facing each other across the notch N is S ′. Assuming that the total contact area at the maximum displacement of the inner ring 18 is the total maximum contact area S ′ _max , the bridge portion 22 (22c) has the displacement when the displacement of the inner ring 18 exceeds a specified value. With increase, the total contact area S ′ is configured to increase within a range of less than S ′ _max .

According to this embodiment, when the displacement of the inner ring 18 becomes equal to or greater than a specified value, the total contact area S ′ increases within the range less than the total maximum contact area S ′ _{max as} the displacement increases. The rigidity of the bridge portion 22 (22c) is not increased rapidly. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

  In one embodiment, as shown in FIG. 6, since the bridge portion 22 (22 c) has the notch N, the contact between the notch N and the other part of the slit St is increased as the displacement of the inner ring 18 increases. The time can be different. Therefore, since the contact area S increases stepwise, the rigidity of the bridge portion 22 (22c) is not increased rapidly. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

In one embodiment, as shown in FIG. 6, the notch N is formed at a portion to which the compressive load of the bridge portion 22 is applied when the inner ring 18 is displaced.
According to this embodiment, since the notch N is formed at a portion where a compressive load is applied, the outer surfaces 23a and 23b of the bridge portion 22 (22c) facing each other across the notch N are brought into contact with each other by the compressive load. it can. Further, by providing a time difference between the contact timing of the wall surface of the notch N and the contact timing of the other part of the slit St, the rigidity of the bridge portion 22 (22c) can be prevented from increasing rapidly. . As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle.

In one embodiment, as shown in FIG. 6, the bridge portion 22 (22 c) has at least one bent portion Be, and the notch N is formed in the bent portion Be.
According to this embodiment, when a compressive load is applied to the bridge portion 22 by the load L applied to the inner ring 18 from the rotating shaft 12, the compressive load is applied to the bent portion Be. Since the notch N is formed in the bent portion Be to which the compressive load is applied, the outer surfaces 23a and 23b of the bridge portion 22 (22c) facing each other across the notch N can contact with each other by the compressive load.

When setting the contact time of the wall surface of the notch N to be different from the contact time of the wall surface of the other part of the slit St, the contact time is made different by setting the size of the gap between them.
Further, when the notch N is formed in the bent portion Be, it may be either on the inner surface or the outer surface with respect to the radius of curvature of the bent portion Be, and a compressive load can be applied in either case.

In one embodiment, as shown in FIG. 6, the notch N is composed of a plurality of notches N (N ₁ , N ₂ ) having different gap sizes.
According to this embodiment, since the sizes of the gaps are different between the plurality of notches, the contact area S can be increased stepwise by giving a time difference to the wall surface contact timing. For example, when there are two notches with different gaps, the contact area S can be increased in three stages.
Therefore, since the rigidity of the bridge portion 22 (22c) can be increased stepwise, changes in the rotation axis position and various changes given to the rotation axis system can be made gentle.

  FIG. 9 is a diagram showing the relationship between the displacement of the inner ring 18 and the contact area S in the embodiment shown in FIG. As shown in FIG. 6, since the contact area S can be increased in three stages, changes in the rotation axis position and various changes given to the rotation axis system can be made gentle.

A rotating machine according to an embodiment includes a rotating shaft 12 and a bearing device 10 having the above-described configuration.
According to this configuration, since the bearing device 10 having the above-described configuration is provided, even when the bridge portion 22 is damaged due to external impact or aging deterioration, or even when an excessive load is applied to the bridge portion 22, the contact area. Since S increases within the range of less than _Smax, the rigidity of the bridge portion 22 is not rapidly increased. As a result, changes in the rotation axis position and various changes applied to the rotation axis system can be made gentle. Therefore, it can be applied to rotating machines such as compressors and steam turbines.

  According to some embodiments, when the bridge portion provided in the inner ring is damaged, or when an excessive load is applied, the rigidity of the bridge portion is gradually changed to change the rotation axis position or rotate. Various changes to the shaft system can be made gentle and the influence can be minimized. Therefore, it can be applied to rotating machines such as compressors and steam turbines.

DESCRIPTION OF SYMBOLS 10 Bearing apparatus 12 Rotating shaft 14 Bearing part 16 Squeeze film damper 18 Inner ring 18a Wall surface 20 Outer ring 20a Wall surface 22 (22a, 22b, 22c) Bridge part 23a, 23b Outer surface 24 Tilting pad 25 Pivot Be Curved part G Oil film formation clearance L load _{N (N 1,} N 2) notches O central axis
Rs1, Rs2, _{R 2} region S contact area S _max maximum contact area S 'total contact area S' _max total contact area _{St (St} 1, St 2) slit St ₁ first slit St ₂ second slit d ₀ touch start point

Claims (13)

A bearing for rotatably supporting the rotating shaft;
A squeeze film damper provided on the outer peripheral side of the bearing portion and including an inner ring and an outer ring facing each other across at least one oil film formation gap;
A bridge portion that connects the inner ring and the outer ring and elastically supports the inner ring on the outer ring;
With
At least a part of the bridge portion faces the inner ring or the outer ring wall surface through a slit,
When the maximum contact area between the outer surface of the bridge portion and the wall surface at the time of maximum displacement of the inner ring is S _max , the bridge portion has the displacement of the inner ring equal to or greater than a specified value, As the displacement increases, the bearing device is configured such that a contact area S between the outer surface and the wall surface of the bridge portion increases within a range of less than _Smax .   2. The bearing device according to claim 1, wherein the bridge portion is configured such that when the displacement of the inner ring becomes equal to or greater than a predetermined value, the contact area S increases stepwise as the displacement increases.   The slit has a plurality of regions having different sizes of gaps, and the outer surface of the bridge portion and the wall surface are configured to contact in stages in the plurality of regions. 2. The bearing device according to 2. The slit includes a first slit facing the wall surface of the inner ring and a second slit facing the wall surface of the outer ring,
The bearing device according to claim 2, wherein the first slit and the second slit include a region having a gap having a different size.   The bearing device according to claim 1, wherein the bridge portion is configured such that the contact area S continuously increases as the displacement increases.   In at least a part of the bridge portion, the slit is configured such that the size of the gap is continuously different, and the outer surface of the bridge portion and the wall surface are continuously contacted in the gap. The bearing device according to claim 5.   The bearing device according to claim 1, wherein the bridge portion has at least one bent portion. A bearing for rotatably supporting the rotating shaft;
A squeeze film damper provided on the outer peripheral side of the bearing portion and including an inner ring and an outer ring facing each other across at least one oil film formation gap;
A bridge portion that connects the inner ring and the outer ring and elastically supports the inner ring on the outer ring;
With
At least a part of the bridge portion faces the inner ring or the outer ring wall surface through a slit,
The bridge portion includes at least one notch opening in the slit,
The total contact area of the first contact area between the outer surface of the bridge portion and the wall surface, and the second contact area between the outer surfaces of the bridge portions facing each other across the notch is S ′,
When the total contact area at the maximum displacement of the inner ring is S ′ _max ,
The bridge portion is configured to increase the total contact area S ′ within a range of less than S ′ _{max as the} displacement increases when the displacement of the inner ring exceeds a predetermined value. A bearing device.   The bearing device according to claim 8, wherein the bridge portion is configured such that the contact area S increases stepwise as the displacement increases.   The bearing device according to claim 8 or 9, wherein the notch is formed in a portion to which a compressive load of the bridge portion is applied when the inner ring is displaced. The bridge portion has at least one bent portion,
The bearing device according to claim 10, wherein the notch is formed in the bent portion.   The bearing device according to any one of claims 8 to 11, wherein the notch includes a plurality of notches having different gap sizes. A rotation axis;
A bearing device according to any one of claims 1 to 12,
A rotating machine comprising:

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