JP2012122537A - Bearing damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing damper that can present a desired damping property of the damper irrespectively of the vibration amplitude of the rotary shaft of a rotation machine.SOLUTION: There are included a bearing pad 7 rotatably supporting a rotor 2 of the rotation machine; a ring-shaped bearing-housing inner ring 4 arranged at the outer peripheral side of the bearing pad 7; and a bearing-housing outer ring 5 mounted at the outer peripheral side of the bearing-housing inner ring 4 and so arranged as to have a damper clearance 19 to the bearing-housing inner ring 4. The bearing-housing inner ring 4 includes an oil path 13 opening to the damper clearance 19 and also opening to an inner peripheral surface opposite to the bearing pad 7. The bearing-housing inner ring 4 includes an oil path 16 opening to the damper clearance 19 and also opening to the inner peripheral surface 4b opposite to the bearing pad 7; and oil paths 17 and 18 opening to the damper clearance 19 and also opening to an inner peripheral surface 4c opposite to the rotor 2 of the rotation machine.

Description

  The present invention relates to a bearing damper, and more particularly to a bearing damper suitable for use in a rotating machine having a large shaft system such as a gas turbine, a rotating machine using a low-viscosity fluid such as a pump or a water turbine, and the like.

  As a bearing damper, there is a squeeze film damper in which a damper is disposed on the back of the bearing. An example of this type of bearing damper will be described with reference to FIG. As shown in FIG. 8, the bearing damper 100 is a device that is attached to a bearing base 101 of a rotary machine such as a gas turbine, a pump, or a water turbine, and rotatably supports a rotor (rotary shaft) 102 of the rotary machine. The bearing damper 100 includes an annular bearing housing 103 and four bearing pads 107 fitted into the bearing housing 103. The bearing housing 103 includes a bearing housing inner ring 104 and an arc-shaped bearing housing outer ring 105 attached to the outer periphery of the bearing housing inner ring 104 by a support rod 106. The bearing pad 107 is formed in an arc shape in cross section.

  The bearing stand 101 is formed with an oil supply groove 112 communicating with an oil supply line 111 extending in the axial direction. Grooves 115 and 116 are formed in the bearing housing outer ring 105 so as to be positioned at both axial ends on the inner peripheral surface side facing the bearing housing inner ring 104. The bearing housing outer ring 105 is formed with oil passages 113 and 114 that open to the approximate center in the axial direction on the outer peripheral surface side and open to the groove portions 115 and 116 on the inner peripheral surface side, respectively. The bearing housing inner ring 104 is formed with oil passages 117 and 118 that open to the groove portions 115 and 116 and open to the inner peripheral surface facing the bearing pad 107. A damper gap (annular gap) 119 is formed between the outer peripheral surface of the bearing housing inner ring 104 and the inner peripheral surface of the bearing housing 105.

  Therefore, when the hydraulic oil is supplied to the oil supply line 111, the hydraulic oil flows to the outer peripheral surface side of the bearing pad 107 through the oil supply groove 112, the oil passages 113 and 114, the groove portions 115 and 116, and the oil passages 117 and 118. The hydraulic oil flows to the inner peripheral surface side of the bearing pad 107, and an oil film is formed in the bearing gap 108 between the bearing pad 107 and the rotor 102 of the rotary machine. Further, the hydraulic oil is also circulated to the damper gap 119 via the groove portions 115 and 116. In the damper gap 119, hydraulic oil is supplied at the same pressure from the front and rear in the axial direction. Therefore, when the hydraulic oil is filled in the damper gap 119, the hydraulic oil is stagnated in the damper gap 119.

  In the bearing damper having the above-described configuration, when the rotor 102 of the rotating machine vibrates due to the rotation of the rotor 102, the bearing housing inner ring 104 and the bearing housing outer ring 105 vibrate in the radial direction, and the radial interval of the damper gap 119 relatively changes. Thus, the vibration energy of the shaft system is absorbed by the vibration damping effect due to the viscosity of the fluid such as hydraulic oil existing in the damper gap 119, and the shaft system is damped.

  Examples of prior art documents describing squeeze film dampers include the following.

Japanese Patent Laid-Open No. 11-141545 (see, for example, [FIG. 1])

  By the way, although the damper characteristic of the bearing damper is influenced by the Reynolds number of the hydraulic oil (liquid) flowing through the damper gap, it is necessary to grasp the speed of the hydraulic oil in order to specify the Reynolds number. The typical speed of the hydraulic oil is the vibration speed (vibration amplitude) of the shaft (rotor of the rotating machine), and the Reynolds number changes according to this speed, and the damper characteristics also change according to this Reynolds number. Conventional bearing dampers have a small shaft system and a very small Reynolds number, so the damper characteristics are not affected. However, in the squeeze film damper described in Patent Document 1 described above and the bearing damper 100 configured as described above, the hydraulic oil is sealed in the damper gap or stagnated in the damper gap 119, and the vibration of the shaft When the flow state of the hydraulic oil changes greatly depending on the state, the Reynolds number may be very difficult to predict. In particular, when the shaft system becomes large or the damper gap becomes wide, the Reynolds number increases accordingly, and in the region where the Reynolds number is large, the damping effect generated according to the vibration speed of the shaft increases due to the fluid inertia force On the other hand, there is a possibility that the shaft vibration stability may be lowered because the damper gap is constrained and becomes difficult to move.

  In view of the above, the present invention has been made to solve the above-described problems, and provides a bearing damper capable of expressing desired damping characteristics of the damper regardless of the vibration amplitude of the rotating shaft of the rotating machine. The purpose is to do.

The bearing damper according to the first invention for solving the above-described problem is:
A bearing that rotatably supports the rotating shaft of the rotating machine;
An annular bearing housing inner ring disposed on the outer peripheral side of the bearing portion;
A bearing housing outer ring mounted on the outer peripheral side of the bearing housing inner ring and disposed with a gap with respect to the bearing housing inner ring;
An oil supply path that opens in the gap is provided in the bearing housing outer ring,
A first oil discharge passage that opens to the clearance and opens to an inner peripheral surface that faces the bearing portion, and a first oil discharge passage that opens to the clearance and opens to an inner peripheral surface that faces the rotating shaft of the rotating machine. 2 oil discharge passages are provided in the inner ring of the bearing housing.

The bearing damper according to the second invention for solving the above-described problem is
A bearing damper according to a first invention,
The oil supply path communicates with one end of the gap in the axial direction;
The first oil discharge passage communicates with one end of the gap in the axial direction;
The second oil discharge path communicates with the other end portion of the gap in the axial direction.

A bearing damper according to a third invention for solving the above-described problem is
A bearing damper according to the first or second invention,
A plurality of grooves extending along the axial direction are formed on the outer peripheral surface of the inner ring of the bearing housing facing the outer ring of the bearing housing in the circumferential direction.

A bearing damper according to a fourth invention for solving the above-described problem is
A bearing that rotatably supports the rotating shaft of the rotating machine;
An annular bearing housing inner ring disposed on the outer peripheral side of the bearing portion;
A bearing housing outer ring mounted on the outer peripheral side of the bearing housing inner ring and disposed with a gap with respect to the bearing housing inner ring;
An oil supply path that opens in the axial center of the gap is provided in the bearing housing outer ring,
While opening at one end of the gap in the axial direction and opening at the other end of the gap in the axial direction, the first oil discharge path that opens to the inner peripheral surface facing the bearing portion, The bearing housing inner ring is provided with a second oil discharge passage that opens to an inner peripheral surface facing the bearing portion.

A bearing damper according to a fifth aspect of the present invention for solving the above-described problem is
A bearing damper according to a fourth invention,
A plurality of grooves extending along the axial direction are formed on the outer peripheral surface of the inner ring of the bearing housing facing the outer ring of the bearing housing in the circumferential direction.

  According to the bearing damper of the present invention, the hydraulic oil can be circulated through the gap at a constant speed, and the gap is circulated with respect to fluctuations in the flow speed of the hydraulic oil in the gap due to vibration of the rotating shaft of the rotary machine. By setting the speed of the hydraulic oil to be high, a desired damper damping characteristic can be exhibited regardless of the vibration amplitude of the rotating shaft of the rotating machine.

It is sectional drawing of the bearing damper which concerns on 1st embodiment of this invention. It is a figure for demonstrating the flow of the hydraulic fluid in the damper clearance gap of a bearing damper. It is sectional drawing of the bearing damper which concerns on 2nd embodiment of this invention. It is a figure for demonstrating the flow of the hydraulic fluid in the damper clearance gap of a bearing damper. It is a side view of the bearing damper which concerns on 3rd embodiment of this invention. It is explanatory drawing of the bearing housing inner ring | wheel with which a bearing damper comprises. It is a figure for demonstrating the flow of the hydraulic fluid in the damper clearance gap of a bearing damper. It is sectional drawing of the conventional bearing damper.

  The bearing damper according to the present invention will be specifically described in each embodiment.

[First embodiment]
A bearing damper according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 1, a bearing damper 10 according to the present embodiment is attached to a bearing stand 1 of a rotary machine such as a gas turbine, a pump, or a water turbine, and rotatably supports a rotor (rotary shaft) 2 of the rotary machine. Equipment. The bearing damper 10 includes an annular bearing housing 3 and four bearing pads 7 that are fitted in the bearing housing 3. The bearing housing 3 is mounted on the outer periphery of the bearing housing inner ring 4 and the outer periphery of the bearing housing inner ring 4 by a support rod 6, and has a damper gap (annular gap) 19 with respect to the outer circumferential surface 4 a at the substantially central portion in the axial direction of the bearing housing inner ring 4. It is comprised with the circular-arc-shaped bearing housing outer ring | wheel 5 arrange | positioned. The bearing pad 7 is formed in an arc shape in cross section.

  The bearing stand 1 is formed with an oil supply groove 12 that communicates with an oil supply line 11 extending in the axial direction. Grooves 14 and 15 are formed in the bearing housing outer ring 5 so as to be located on both ends in the axial direction on the inner peripheral surface 5 a side facing the bearing housing inner ring 4. In the bearing housing outer ring 5 and the bearing stand 1, an oil passage 13 that opens to the groove portion 14 and opens to the oil supply groove 12 is formed. The bearing housing inner ring 4 is formed with an oil passage 16 that opens to the groove portion 14 on the outer peripheral surface 4 a side and opens to the inner peripheral surface 4 b side facing the bearing pad 7. The bearing housing inner ring 4 has an oil passage 17 that opens in the groove 15 and extends in the axial direction, and an inner peripheral surface 4c that communicates with the oil passage 17 and extends in the radial direction and faces the rotor 2 of the rotary machine. An oil passage 18 that is open to the bottom is formed. That is, the oil passage 13 is configured as an oil supply passage for supplying hydraulic oil to the damper gap 19. The oil passage 16 is configured as a first oil discharge passage through which hydraulic oil is discharged from the damper gap 19 to the bearing pad 7. The oil passage 17 and the oil passage 18 are configured as a second oil discharge passage for discharging the hydraulic oil from the damper gap 19 to the rotating shaft 2 of the rotary machine.

  Therefore, when hydraulic oil is supplied to the oil supply line 11, the hydraulic oil flows through the oil supply groove 12, the oil passage 13, the groove portion 14, and the oil passage 16 to the outer peripheral surface side of the bearing pad 7. Then, the hydraulic oil flows to the inner peripheral surface side of the bearing pad 7 so that an oil film is formed in the bearing gap 8 between the bearing pad 7 and the rotor 2 of the rotary machine. Further, the hydraulic oil is also circulated to the damper gap 19 through the groove portion 14. Specifically, as shown in FIG. 2, when hydraulic oil is supplied from the fluid inlet 13 a of the oil passage 13 to the groove portion 14, the hydraulic oil flows in the circumferential direction along the groove portion 14, and enters the damper gap 19. Circulate. The hydraulic fluid that has flowed through the damper gap 19 flows in the axial direction and flows into the groove portion 15. The hydraulic oil that has circulated through the groove portion 15 circulates in the circumferential direction along the groove portion 15, and circulates through the fluid outlet 17 a to the oil passage 17. The hydraulic oil is discharged out of the system through the oil passage 18. Thus, the damper gap 19 has a structure in which hydraulic oil is supplied only from one end (groove portion 14) side in the axial direction, and a pressure difference is generated at both ends in the axial direction of the damper gap 19. Therefore, the hydraulic oil always flows in the axial direction in the damper gap 19 at a constant speed.

  Therefore, according to the bearing damper 10 according to the present embodiment, the hydraulic oil flows through the damper gap 19 at a constant speed, and the fluctuation of the flow speed of the hydraulic oil in the damper gap 19 due to the vibration of the rotor 2 of the rotary machine. On the other hand, by setting the speed of the hydraulic oil flowing through the damper gap 19 to be large, the number of lay nozzles of the damper becomes constant regardless of the vibration of the rotor 2 of the rotary machine, and a desired value is obtained regardless of the vibration amplitude. The damping characteristic of the damper can be expressed.

[Second Embodiment]
A bearing damper according to a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, it is the structure which changed the oil path provided in the bearing housing outer ring | wheel and the bearing housing inner ring | wheel with which the bearing damper which concerns on 1st embodiment mentioned above comprised, Comprising: Otherwise, it comprises the same apparatus. . In the present embodiment, the same components as those of the bearing damper according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 3, the bearing damper 20 according to the present embodiment includes a bearing housing outer ring 5 in which a groove portion 22 is formed at the center in the axial direction on the inner peripheral surface 5 a side facing the bearing housing inner ring 4. . In the bearing housing outer ring 5 and the bearing stand 1, an oil passage 21 that opens to the groove portion 22 and opens to the oil supply groove 12 is formed. As shown in FIG. 4, a plurality of fluid inlets 21 a of the oil passage 21 are provided in the circumferential direction on the inner peripheral surface 5 a of the bearing housing outer ring 5. The bearing housing inner ring 4 is formed with an oil passage 23 that opens to the groove 15 on the outer peripheral surface 4 a side and opens to the inner peripheral surface 4 b side facing the bearing pad 7. The bearing housing outer ring 5 is mounted on the outer periphery of the bearing housing inner ring 4 by a support rod 6 and is disposed with a damper gap (annular gap) 24 with respect to the outer peripheral surface 4a at the substantially central portion in the axial direction of the bearing housing inner ring 4. Yes. That is, the oil passage 21 is configured as an oil supply passage for supplying hydraulic oil to the damper gap 24. The oil passage 16 is configured as a first oil discharge passage through which hydraulic oil is discharged from the damper gap 24 to the bearing pad 7. The oil passage 23 is configured as a second oil discharge passage through which hydraulic oil is discharged from the damper gap 24 to the bearing pad 7.

  Accordingly, when hydraulic oil is supplied to the oil supply line 11, the hydraulic oil flows through the damper gap 24 via the oil supply groove 12, the oil passage 21, and the groove portion 22. Specifically, as shown in FIG. 4, when hydraulic oil is supplied from the fluid inlet 21 a of the oil passage 21 to the groove portion 22, the hydraulic oil flows from the groove portion 22 to both ends in the axial direction, and passes through the damper gap 24. It circulates in the groove parts 14 and 15 through. The hydraulic fluid that has flowed through the groove portions 14 and 15 flows through the oil passages 16 and 23 to the outer peripheral surface side of the bearing pad 7. Then, the hydraulic oil flows to the inner peripheral surface side of the bearing pad 7 so that an oil film is formed in the bearing gap 8 between the bearing pad 7 and the rotor 2 of the rotary machine. As described above, the damper gap 24 has a structure in which the hydraulic oil is supplied only from the central portion in the axial direction, and a pressure difference is generated between the central portion in the axial direction of the damper gap 24 and both ends thereof. The hydraulic oil always flows through the damper gap 24 from the axially central portion to both end portions at a constant speed.

  Therefore, according to the bearing damper 20 according to the present embodiment, like the bearing damper 10 according to the first embodiment described above, the hydraulic oil circulates at a constant speed in the damper gap 24, and the rotating machine The number of lay nozzles of the damper is set so that the speed of the hydraulic oil flowing through the damper gap 24 is increased with respect to the fluctuation of the flow speed of the hydraulic oil in the damper gap 24 due to the vibration of the rotor 2. Therefore, a desired damping characteristic of the damper can be exhibited regardless of the vibration amplitude. Further, by providing a plurality of fluid inlets 21a of the oil passage 21 for supplying the hydraulic oil to the damper gap 24 in the circumferential direction, the deviation of the speed distribution of the hydraulic oil in the circumferential direction is suppressed.

  Furthermore, the distance that hydraulic oil flows through the damper gap 24 is related to the first embodiment in which the damper gap 19 flows from one end (groove 14) side in the axial direction to the other end (groove 15). Since it is shorter than the bearing damper 10, the flow resistance of the hydraulic oil is reduced, and desired damper characteristics can be expressed more stably.

[Third embodiment]
A bearing damper according to a third embodiment of the present invention will be described with reference to FIGS. 5, 6, and 7. In the present embodiment, a part of the inner ring of the bearing housing included in the bearing damper according to the first embodiment described above is changed, and the other devices are the same. In the present embodiment, the same components as those of the bearing damper according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 5, 6, and 7, the bearing damper 30 according to the present embodiment is located on the outer peripheral surface 4 a facing the inner peripheral surface 5 a of the bearing housing outer ring 5 and extends in the axial direction. A bearing housing inner ring 4 having a plurality of groove portions 31 formed in the circumferential direction is provided. The bearing housing outer ring 5 is mounted on the outer periphery of the bearing housing inner ring 4 by a support rod 6 and is disposed with a damper gap (annular gap) 32 with respect to the outer peripheral surface 4a at the substantially central portion in the axial direction of the bearing housing inner ring 4. Yes. That is, the oil passage 16 is configured as a first oil discharge passage through which hydraulic oil is discharged from the damper gap 32 to the bearing pad 7. The oil passage 17 and the oil passage 18 are configured as a second oil discharge passage for discharging the hydraulic oil from the damper gap 32 to the rotary shaft 2 of the rotary machine.

  Therefore, when hydraulic oil is supplied to the oil supply line 11, the hydraulic oil flows through the oil supply groove 12, the oil passage 13, the groove portion 14, and the oil passage 16 to the outer peripheral surface side of the bearing pad 7. Then, the hydraulic oil flows to the inner peripheral surface side of the bearing pad 7 so that an oil film is formed in the bearing gap 8 between the bearing pad 7 and the rotor 2 of the rotary machine. Further, the hydraulic oil is also circulated into the damper gap 32 through the groove portion 14. Specifically, as shown in FIG. 7, when hydraulic oil is supplied from the fluid inlet 13 a of the oil passage 13 to the groove portion 14, the hydraulic oil circulates in the circumferential direction along the groove portion 14 and enters the damper gap 32. Circulate. The hydraulic fluid that has flowed through the damper gap 32 flows in the axial direction along the groove 31 and flows into the groove 15. The hydraulic oil that has circulated through the groove portion 15 circulates in the circumferential direction along the groove portion 15, and circulates through the fluid outlet 17 a to the oil passage 17. The hydraulic oil is discharged out of the system through the oil passage 18. As described above, the damper gap 32 has a structure in which hydraulic oil is supplied only from one end portion (groove portion 14) side in the axial direction, and a pressure difference is generated at both end portions in the axial direction of the damper gap 32. Therefore, the hydraulic oil always flows in the axial direction in the damper gap 32 at a constant speed.

  Therefore, according to the bearing damper 30 according to the present embodiment, the hydraulic oil circulates at a constant speed in the damper gap 32 as in the bearing damper 10 according to the first embodiment described above. The number of lay nozzles of the damper is set so that the speed of the hydraulic oil flowing through the damper gap 32 is increased with respect to fluctuations in the flow speed of the hydraulic oil in the damper gap 32 due to vibration of the rotor 2. Therefore, a desired damping characteristic of the damper can be exhibited regardless of the vibration amplitude.

  Furthermore, by providing a plurality of axially extending grooves 31 located on the outer peripheral surface 4a of the bearing housing inner ring 4, the hydraulic fluid is more smoothly transferred in the axial direction through the damper gap 32. I can guide you. Thereby, the damping characteristic of a desired damper can be expressed stably.

  In the bearing damper according to the second embodiment described above, a groove portion extending in the axial direction on the outer peripheral surface 4a of the bearing housing inner ring 4 facing the inner peripheral surface 5a of the bearing housing outer ring 5 extends in the circumferential direction. It is also possible to provide a plurality of them. According to such a bearing damper, the same effects as the bearing damper according to the third embodiment described above can be obtained.

  According to the bearing damper according to the present invention, the hydraulic oil can be circulated through the damper gap at a constant speed, and the damper gap is formed against fluctuations in the flow velocity of the hydraulic oil in the damper gap due to the vibration of the rotor of the rotating machine. By setting the speed of the circulating fluid to increase, it is possible to express the desired damping characteristics of the damper regardless of the vibration amplitude of the rotor of the rotating machine. Therefore, industries that use gas turbines, pumps, water turbines, etc. It can be used beneficially.

DESCRIPTION OF SYMBOLS 1 Bearing stand 2 Rotor of rotary machine 3 Bearing housing 4 Bearing housing inner ring 5 Bearing housing outer ring 6 Support rod 7 Bearing pad (bearing part)
8 Bearing clearance 10 Bearing damper 11 Oil supply line 12 Oil supply groove 13 Oil passage (oil supply passage)
13a Fluid inlets 14 and 15 Groove portion 16 Oil passage (first oil discharge passage)
17, 18 Oil passage (second oil discharge passage)
17a Fluid outlet 19 Damper gap 20 Bearing damper 21 Oil passage (oil supply passage)
22 Groove 23 Oil passage (second oil discharge passage)
24 Damper clearance 30 Bearing damper 31 Groove 32 Damper clearance

Claims (5)

A bearing that rotatably supports the rotating shaft of the rotating machine;
An annular bearing housing inner ring disposed on the outer peripheral side of the bearing portion;
A bearing housing outer ring mounted on the outer peripheral side of the bearing housing inner ring and disposed with a gap with respect to the bearing housing inner ring;
An oil supply path that opens in the gap is provided in the bearing housing outer ring,
A first oil discharge passage that opens to the clearance and opens to an inner peripheral surface that faces the bearing portion, and a first oil discharge passage that opens to the clearance and opens to an inner peripheral surface that faces the rotating shaft of the rotating machine. A bearing damper, wherein two oil discharge passages are provided in the inner ring of the bearing housing. The bearing damper according to claim 1,
The oil supply path communicates with one end of the gap in the axial direction,
The first oil discharge path communicates with one end of the gap in the axial direction,
The second oil discharge passage communicates with the other end portion in the axial direction of the gap. A bearing damper according to claim 1 or 2, wherein
A bearing damper, wherein a plurality of grooves extending along the axial direction are formed on the outer peripheral surface of the inner ring of the bearing housing facing the outer ring of the bearing housing in the circumferential direction. A bearing that rotatably supports the rotating shaft of the rotating machine;
An annular bearing housing inner ring disposed on the outer peripheral side of the bearing portion;
A bearing housing outer ring mounted on the outer peripheral side of the bearing housing inner ring and disposed with a gap with respect to the bearing housing inner ring;
An oil supply path that opens in the axial center of the gap is provided in the bearing housing outer ring,
While opening at one end of the gap in the axial direction and opening at the other end of the gap in the axial direction, the first oil discharge path that opens to the inner peripheral surface facing the bearing portion, A bearing damper, characterized in that a second oil discharge passage opening on an inner peripheral surface facing the bearing portion is provided in the bearing housing inner ring. A bearing damper according to claim 4, wherein
A bearing damper, wherein a plurality of grooves extending along the axial direction are formed on the outer peripheral surface of the inner ring of the bearing housing facing the outer ring of the bearing housing in the circumferential direction.

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