Journal bearing and rotating equipment using the same

Abstract

A journal bearing (100) for supporting a rotating shaft (900) of a rotating device comprises: an oil supply nozzle (30) having an oil distribution portion (301) extending axially along the rotating shaft and supplying lubricating oil (800); and a pad (21) arranged behind the oil supply nozzle in the rotation direction of the rotating shaft and supporting the rotating shaft so as to be rotatable, the inner peripheral surface of the pad facing the outer peripheral surface of the rotating shaft having an opening surface (21a1) in which the radial spacing between the inner peripheral surface and the outer peripheral surface of the rotating shaft decreases from the front end surface of the pad in the rotation direction of the rotating shaft toward the rear in the rotation direction, and a bubble discharge path (40) for discharging bubbles (801) mixed in the lubricating oil is provided between the oil distribution portion and the pad, thereby obtaining a journal bearing and a rotating device using the journal bearing that can remove bubbles contained in the oil and efficiently fill the gap with oil with a smaller oil supply amount.

Description

Technical Field

[0001] The present invention relates to a journal bearing and a rotating device using the journal bearing. Background Art

[0002] Patent Document 1 describes a pad-type journal bearing using direct lubrication. This journal bearing comprises: a plurality of pads, pivotably mounted within the bearing inner ring, supporting the journal in a self-aligning manner; and an oil supply nozzle, positioned upstream of each pad relative to the rotational direction of the rotating shaft, for supplying lubricating oil to the gap between the inner circumference of the pad and the outer circumference of the rotating shaft. A chamfered portion, inclined toward the inner circumference of the pad, is formed at least in the center of the front edge of the pad. Patent Document 1 states that the chamfered portion allows oil to flow efficiently into the gap, thereby enabling the gap to be filled with oil with a relatively small amount of oil supplied.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-274432 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, the journal bearing of Patent Document 1 has a problem in that the shear flow in the rotational direction of the rotating shaft is strong near the outer peripheral surface of the rotating shaft, and air bubbles contained in the oil flow into the gap, so the gap may not be filled with oil.

[0008] Furthermore, near the chamfered portion of the pad, which is slightly spaced from the outer circumference of the rotating shaft, oil and bubbles flowing in the direction of the rotating shaft's rotation are rebounded by the chamfered portion, generating a swirling flow in the opposite direction of the rotating shaft's rotation. The density of the air bubbles contained in the oil is lower than that of the oil, and the centrifugal force generated by the swirling flow on the bubbles is smaller than that of the oil. Therefore, the bubbles tend to remain in the center of the swirling flow. Consequently, bubbles sometimes aggregate near the chamfered portion of the pad where the swirling flow is generated, becoming larger bubbles and eventually invading the gap. These bubbles are more easily compressed than oil. Therefore, when bubbles intrude into the gap, the oil film pressure supporting the rotating shaft decreases, causing unstable vibration of the rotating shaft and pad.

[0009] The present application has been made to solve the above-mentioned problems, and an object thereof is to provide a journal bearing and a rotating device that can remove air bubbles contained in oil and efficiently fill the gap with oil with a small amount of oil supply.

[0010] Means for solving problems

[0011] The journal bearing involved in the present application is a journal bearing for supporting a rotating shaft of a rotating device, comprising: an oil supply nozzle, the oil supply nozzle having an oil distribution portion extending along the axial direction of the rotating shaft and supplying lubricating oil; and a pad, the pad being arranged behind the oil supply nozzle in the rotation direction of the rotating shaft and supporting the rotating shaft so as to be rotatable, the inner peripheral surface of the pad facing the outer peripheral surface of the rotating shaft having an opening surface in which the radial distance between the inner peripheral surface and the outer peripheral surface of the rotating shaft decreases from the front end surface of the pad in the rotation direction of the rotating shaft toward the rear in the rotation direction, and a bubble discharge path for discharging bubbles mixed in the lubricating oil is provided between the oil distribution portion and the pad.

[0012] Effects of the Invention

[0013] According to the present invention, the inner circumferential surface of the pad behind the oil supply nozzle has an opening in which the radial distance between the inner circumferential surface and the outer circumferential surface of the rotating shaft decreases from the front end surface of the pad in the rotational direction of the rotating shaft toward the rear in the rotational direction. This allows for efficient oil supply to the gap between the inner circumferential surface of the pad and the outer circumferential surface of the rotating shaft. Furthermore, because a bubble discharge path is provided between the oil distribution portion and the pad to discharge bubbles mixed with the lubricating oil, bubbles are prevented from invading the oil film area between the inner circumferential surface of the pad and the outer circumferential surface of the rotating shaft, thereby preventing unstable vibration of the rotating shaft and the pad.

[0014] As described above, according to the present application, it is possible to obtain a journal bearing and a rotating electrical machine using the journal bearing, which removes air bubbles contained in oil and efficiently fills the gap with oil with a small amount of oil supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view perpendicular to the axial direction, showing the structure of the journal bearing according to the first embodiment.

[0016] Figure 2 This is a diagram showing the structure of the journal bearing according to the first embodiment. Figure 1 AA cross-sectional view.

[0017] Figure 3 This is a diagram showing the structure of the journal bearing according to the first embodiment. Figure 2 BB cross-sectional view.

[0018] Figure 4 This figure shows the structure of the oil supply nozzle and the surrounding area of ​​the journal bearing according to the first embodiment. Figure 3 Detailed cross-sectional view of part C.

[0019] Figure 5 This figure shows the structure of the oil supply nozzle and the surrounding area of ​​the journal bearing according to the first embodiment. Figure 3 Detailed cross-sectional view of part C.

[0020] Figure 6 This figure shows the structure of the oil supply nozzle and the surrounding area of ​​the journal bearing according to the first embodiment. Figure 3 Detailed cross-sectional view of part C.

[0021] Figure 7 This figure shows the structure of the oil supply nozzle and the surrounding area of ​​the journal bearing according to the first embodiment. Figure 3 Detailed cross-sectional view of part C.

[0022] Figure 8 It is a cross-sectional view perpendicular to the axial direction, showing the structure of a journal bearing according to the second embodiment.

[0023] Figure 9 This is a diagram showing the effect of reducing the amount of oil supplied to the journal bearing according to the second embodiment.

[0024] Figure 10 This is a cross-sectional view showing the structure of the periphery of the oil supply nozzle of the journal bearing according to the third embodiment.

[0025] Figure 11 This is a cross-sectional view showing the structure of the periphery of the oil supply nozzle of the journal bearing according to the fourth embodiment.

[0026] Figure 12 It is a cross-sectional view of main parts showing the structure of a journal bearing according to a fifth embodiment.

[0027] Figure 13 It is a cross-sectional view of main parts showing the structure of a journal bearing according to a sixth embodiment.

[0028] Figure 14 It is a cross-sectional view of main parts showing the structure of a journal bearing according to a seventh embodiment.

[0029] Figure 15 This is a cross-sectional view showing the structure of a rotating machine using the journal bearing according to the eighth embodiment. DETAILED DESCRIPTION

[0030] Implementation method 1.

[0031] The journal bearing of the first embodiment is a sliding bearing that rotatably supports a rotating shaft. The journal bearing of this embodiment can be applied to various rotating devices such as rotating electrical machines. Figure 1 : is a cross-sectional view showing the structure of the journal bearing 100 of this embodiment. Figure 1 , a cross section obtained by cutting the journal bearing 100 and the rotating shaft 900 along a plane perpendicular to the axis of the rotating shaft 900 is shown. Figure 2 It shows Figure 1 Cross-sectional view of section AA. Figure 1 The up and down directions in , for example, represent the vertical up and down directions. Figure 1 and the following Figure 3 In the following figures, arrows are used to indicate the rotation direction of the rotating shaft 900. In addition, the front side of the rotating shaft 900 in the rotation direction is referred to as the upstream side, and the rear side of the rotating shaft 900 in the rotation direction is referred to as the downstream side.

[0032] like Figure 1 and Figure 2 As shown in FIG. 1 , the journal bearing 100 has an annular shape as a whole. A rotating shaft 900 is inserted into the journal bearing 100. The journal bearing 100 is configured to support the rotating shaft 900 so that the rotating shaft 900 can rotate freely. The rotating direction of the rotating shaft 900 is Figure 1 The axis of the rotating shaft 900 extends horizontally. In the following description, the direction parallel to the axis of the rotating shaft 900 is referred to as the axial direction. Furthermore, the radial direction centered on the axis is referred to as the radial direction. The circumferential direction centered on the axis is referred to as the circumferential direction.

[0033] The journal bearing 100 includes a carrier ring 10 disposed on the outer circumference of a rotating shaft 900; a downstream pad 20 disposed on the outer circumference of the rotating shaft 900 and the inner circumference of the carrier ring 10, and disposed downstream in the rotational direction of the rotating shaft 900; and an upstream pad 21 disposed upstream in the rotational direction of the rotating shaft 900. The downstream pad 20 and the upstream pad 21 are disposed between the lower half of the outer circumference of the rotating shaft 900 and the lower half of the inner circumference of the carrier ring 10. The downstream pad 20 and the upstream pad 21 are disposed at different circumferential positions along the outer circumference of the rotating shaft 900. The upstream pad 21 is disposed upstream of the downstream pad 20 at intervals in the rotational direction of the rotating shaft 900.

[0034] In the present embodiment, each of the downstream pad 20 and the upstream pad 21 is configured to be tiltable relative to the outer peripheral surface of the rotating shaft 900. The journal bearing 100 including such a downstream pad 20 and upstream pad 21 is referred to as a tilting pad journal bearing.

[0035] The journal bearing 100 includes an oil supply nozzle 30 that supplies lubricating oil 800 between the rotating shaft 900 and each of the downstream pad 20 and the upstream pad 21. The oil supply nozzle 30 is located upstream of the upstream pad 21. The oil supply nozzle 30 includes an oil distribution portion 301 having a plurality of axially arranged oil supply holes 301a that distribute and supply oil in the axial direction, and an oil supply port 302 that supplies oil to the oil distribution portion 301. When the rotating shaft 900 rotates, the lubricating oil 800 supplied from the oil supply holes 301a flows in the same direction as the rotating shaft 900 due to the shear force generated by the rotation of the rotating shaft 900. In other words, the flow direction of the lubricating oil 800 in the journal bearing 100 is the same as the rotation direction of the rotating shaft 900. Furthermore, side plates 50 are arranged on both sides of the journal bearing 100 in the axial direction, and lubricating oil 800 is supplied to a space surrounded by the carrier ring 10 , the side plates 50 , and the rotating shaft 900 .

[0036] Next, the structure of the upstream pad 21 is described. The upstream pad 21 has a partially cylindrical shape as a whole. The upstream pad 21 has an inner circumferential surface 21a, an outer circumferential surface 21b and a front end surface 21c. The inner circumferential surface 21a is arranged to face the outer circumferential surface of the rotating shaft 900. The outer circumferential surface 21b is arranged to face the inner circumferential surface of the carrier ring 10. The upstream front end surface 21c is an end surface formed on the upstream side relative to the inner circumferential surface 21a and connecting the inner circumferential surface 21a and the outer circumferential surface 21b. In addition, the inner circumferential surface 21a has a partially cylindrical surface 21a1 and an opening surface 21a2 arranged on the upstream side of the partially cylindrical surface 21a1 and located closer to the outer diameter side than the partially cylindrical surface 21a1.

[0037] The journal bearing 100 includes an outer wall surface 3011 located downstream of the oil supply hole 301a in the outer wall surface of the oil distribution portion 301 and a bubble discharge path 40 surrounded by the front end surface 21c or the opening surface 21a2 of the upstream pad 21. Figure 3 It shows Figure 2 The cross-sectional view of the BB section, Figure 4 It shows Figure 3 Here, the bubble discharge path 40 is surrounded by a surface closest to the outer peripheral surface of the rotation axis 900 and a surface farthest from the outer peripheral surface of the rotation axis 900, among the surfaces perpendicular to the front end surface 21c or the opening surface 21a2 and intersecting the outer wall surface 3011.

[0038] use Figure 5 、 Figure 6 、 Figure 7 The flow of oil and air in this embodiment will be described. Figure 4 Likewise, these figures show Figure 3The figure shows the details of the C part of the journal bearing 100. Inside the journal bearing 100, the vertical upper part is an air layer, and the vertical lower part is an oil layer. At the boundary surface between the air layer and the oil layer, air is drawn into the oil layer and forms bubbles 801 due to the shearing caused by the rotation of the rotating shaft 900. Figure 5 The thick arrows in the figure indicate the flow of lubricating oil 800 and air bubbles 801. Lubricating oil 800 supplied from oil supply hole 301a flows downstream together with surrounding air bubbles 801. However, at least a portion of lubricating oil 800 passes through the gap between opening surface 21a2 and the outer peripheral surface of rotating shaft 900 and then passes through the gap between partial cylindrical surface 21a1 and the outer peripheral surface of rotating shaft 900.

[0039] The oil (defined as the oil film) in the gap (defined as the oil film area) between the partial cylindrical surface 21a1 and the outer circumference of the rotating shaft 900 is sheared by the rotation of the rotating shaft 900, generating a force (defined as the oil film pressure) perpendicular to the partial cylindrical surface 21a1 and the outer circumference of the rotating shaft 900. When the rotating shaft 900 rotates at high speeds, this oil film pressure supports the rotating shaft 900, preventing contact between the rotating shaft 900 and the downstream pad 20 or upstream pad 21. This oil film pressure is only generated when the oil film has a wedge shape, where the radial dimension of the oil film decreases toward the downstream side. The effect of generating oil film pressure due to this wedge shape is called the wedge effect. In typical bearings, to effectively achieve the wedge effect, the radius of curvature of the partial cylindrical surface 21a1 can be set to be approximately 0 to 1% larger than the radius of curvature of the rotating shaft 900. Even in large bearings, the radial dimension of the oil film is extremely narrow, at under several hundred μm. Therefore, only a very small amount of lubricating oil 800 supplied from oil supply hole 301a, located near the outer circumferential surface of rotating shaft 900, flows into the oil film area. Most of the remaining oil flows upstream along opening surface 21a2 and is discharged radially outward through bubble discharge path 40. The farther away from the outer circumferential surface of rotating shaft 900, the smaller the effect of the shear flow generated by the rotation of rotating shaft 900, and thus the velocity of the reverse-flowing oil increases.

[0040] Next, the functions of the opening surface 21 a 2 and the bubble discharge path 40 in this embodiment will be described in comparison with a comparative example. Figure 6The thick arrows indicate the flow of large bubbles 801. The forces acting on bubbles 801 include turbulent lift, which acts in a direction away from the wall due to turbulent flow, and resistance, which acts in a direction opposite to the relative velocity between bubbles 801 and the oil. Turbulent lift is proportional to the volume of bubble 801, while resistance is proportional to the surface area of ​​bubble 801. Large bubbles 801 have a relatively large volume relative to their surface area, so the turbulent lift becomes greater relative to the resistance, making them more likely to move away from the outer circumference of rotating shaft 900. Furthermore, the further away from the outer circumference of rotating shaft 900, the greater the speed at which the oil flows upstream along opening surface 21a2. Therefore, large bubbles 801 located near the outer circumference of rotating shaft 900, after being moved away from the outer circumference of rotating shaft 900 by turbulent lift, are efficiently discharged into bubble discharge path 40 by the reverse flow of oil.

[0041] Figure 7 The thick arrows indicate the flow of small bubbles 801. Small bubbles 801 away from the outer circumference of the rotating shaft 900 are efficiently discharged into the bubble discharge path 40 by riding on the countercurrent flow of oil. The opening surface 21a2 is formed so that the minimum radial distance from the outer circumference of the rotating shaft 900 decreases as it moves downstream, thus generating pressure in the oil here as well due to the wedge effect. Small bubbles 801 near the outer circumference of the rotating shaft 900 attempt to flow into the oil film area, but as they move downstream, the minimum radial distance between the opening surface 21a2 and the outer circumference of the rotating shaft 900 decreases, causing the pressure generated in the oil to rise due to the wedge effect. Therefore, according to Henry's law, which states that the solubility of a gas increases with increasing pressure, the small bubbles 801 dissolve in the oil before entering the oil film area.

[0042] As mentioned above, in Figures 1 to 7 The journal bearing 100 of the illustrated embodiment includes an oil distribution portion 301 and a bubble discharge path 40. The oil distribution portion 301 can be positioned at the center of the swirling flow generated by the lubricating oil 800 and bubbles 801 bouncing off the front end surface 21c and the opening surface 21a2, which shears in the direction of rotation of the rotating shaft 900. This can suppress the swirling flow that causes bubbles 801 to remain near the opening surface 21a2. Furthermore, large bubbles 801 are discharged radially outward through the bubble discharge path 40 and, due to buoyancy, are released into the atmosphere vertically above through the gap between the carrier ring 10 and the oil distribution portion 301. Small bubbles 801 remaining near the rotating shaft 900 dissolve in the oil due to the pressure generated by the wedge effect, thereby suppressing the intrusion of bubbles 801 into the oil film area.

[0043] As described above, the journal bearing 100 of this embodiment includes: an oil supply nozzle 30, which has an oil distribution portion 301 extending along the axial direction of the rotating shaft 900 and supplying lubricating oil 800; and an upstream pad 21, which is arranged behind the rotating shaft 900 of the oil supply nozzle 30 in the rotation direction and supports the rotating shaft 900 so that it can rotate freely. The inner peripheral surface 21a of the upstream pad 21 facing the outer peripheral surface of the rotating shaft 900 has an opening surface 21a2 in which the radial distance between the inner peripheral surface 21a and the outer peripheral surface of the rotating shaft 900 decreases from the front end surface 21c in front of the rotating shaft 900 of the upstream pad 21 in the rotation direction toward the rear in the rotation direction, and a bubble discharge path 40 for discharging bubbles 801 mixed in the lubricating oil 800 is provided between the oil distribution portion 301 and the upstream pad 21.

[0044] According to this structure, the air bubbles 801 can be suppressed from invading the oil film area, so the oil film area can be filled with oil with a small amount of oil supply, and unstable vibration can be prevented.

[0045] Furthermore, although the oil supplied from the oil supply nozzle 30 may also contain air bubbles 801, according to the structure of this embodiment, in order to supply the oil ejected from the oil supply hole 301a to the oil film area, the oil, like the surrounding oil, must pass through the gap between the opening surface 21a2 and the outer peripheral surface of the rotating shaft 900. Therefore, the air bubbles 801 in the oil ejected from the oil supply hole 301a are discharged into the bubble discharge path 40 in the same manner as the air bubbles 801 in the surrounding oil. Therefore, the air bubbles 801 in the oil ejected from the oil supply hole 301a can also be suppressed from entering the oil film area, and the oil film area can be filled with oil with a small amount of oil supply, thereby preventing unstable vibration.

[0046] Frictional losses caused by friction between the rotating shaft and the oil are divided into oil film loss (due to shearing within the oil film) and churning loss (due to churning of oil in areas outside the oil film). When losses in the journal bearings relative to the energy of the rotating shaft are defined as bearing losses, the sum of the oil film loss and churning loss is roughly equal. Generally, oil film loss is proportional to the inner circumferential area of ​​the pad, while churning loss is proportional to the oil supply.

[0047] In this embodiment, the oil film area can be filled with oil with a small amount of oil supply, thereby reducing the oil accumulation in areas outside the oil film area. Therefore, according to this embodiment, stirring loss can be reduced, thereby reducing bearing loss of the journal bearing 100.

[0048] In addition, if Figure 1 and Figures 3 to 7As shown in the structure shown, the opening surface 21a2 is formed into a curved surface shape in which the angle formed between a tangent line to the opening surface 21a2 and a tangent line to the outer peripheral surface of the rotating shaft 900 at a radially opposing position relative to the tangent line decreases as it moves downstream. This increases the radial velocity vector of the bubbles 801 flowing back along the opening surface 21a2, allowing them to be efficiently discharged radially outward through the bubble discharge path 40 without being blocked by the oil distribution portion 301. Furthermore, by narrowing the gap between the opening surface 21a2 and the rotating shaft 900 in a quadratic function as it moves downstream, the oil pressure within the gap can be increased more efficiently, thereby more effectively dissolving small bubbles 801 and suppressing their intrusion into the oil film area.

[0049] Implementation method 2.

[0050] A journal bearing 100 according to a second embodiment will be described. Figure 8 1 is a cross-sectional view perpendicular to the axial direction showing the structure of the journal bearing 100 of the present embodiment.

[0051] like Figure 8 As shown, the maximum value α of the angle of the opening surface 21 a 2 in the circumferential direction of the rotation axis 900 is in the range of 8 to 16% relative to the maximum value β of the angle of the inner circumferential surface 21 a in the circumferential direction. Figure 9 This graph shows the oil supply reduction effect of the journal bearing according to this embodiment. The aperture ratio on the horizontal axis is defined as the ratio of angle α to angle β (100α / β), and the oil supply reduction effect on the vertical axis is defined as the ratio of the oil supply that can be reduced by suppressing unstable vibration by including the opening surface 21a2, compared to a case where the upstream pad 21 does not have the opening surface 21a2.

[0052] As the opening ratio increases, the oil pressure generated by the wedge effect in the gap between the opening surface 21a2 and the rotating shaft 900 increases in a quadratic manner. When the opening ratio exceeds 6%, the pressure rises, causing some of the small bubbles 801 to dissolve in the oil. When the opening ratio exceeds 8%, most of the small bubbles 801 dissolve in the oil. Furthermore, as the opening ratio increases, the area of ​​the partial cylindrical surface 21a1 decreases. Therefore, to achieve an oil film pressure that supports only the rotating shaft 900, the rotating shaft 900 approaches the partial cylindrical surface 21a1. Simultaneously, due to the balance of torque at the support position of the upstream pad 21, the upstream pad 21 rotates in the direction opposite to the rotation direction of the rotating shaft 900, reducing the thickness of the upstream side of the oil film. As the thickness of the upstream side of the oil film decreases, it becomes easier to fill the oil film area with oil even with a smaller oil supply. Therefore, in addition to the oil supply reduction effect achieved by bubble removal, an oil supply reduction effect proportional to the opening ratio is achieved.

[0053] However, when the opening ratio exceeds 16%, the oil film thickness may be extremely reduced, causing the rotating shaft 900 to contact the partial cylindrical surface 21a1, or the oil film temperature may be extremely increased due to shearing, which may eventually lead to seizure or abnormal wear of the partial cylindrical surface 21a1. In this case, the engine cannot operate under all oil supply conditions, and the oil supply reduction effect is lost.

[0054] That is to say, if Figure 11 As shown, when the effect brought about by the dissolution of small bubbles 801 and the effect brought about by the reduction of the oil film thickness are added together, by setting the opening ratio to the range of 6 to 16%, a prominent oil supply reduction effect can be obtained, and by limiting the opening ratio to the range of 8 to 16%, a more stably prominent oil supply reduction effect can be obtained.

[0055] With this structure, by setting the opening ratio (i.e., the angle of the circumferential dimension of the opening surface 21a2 relative to the circumferential dimension of the inner circumferential surface 21a of the upstream pad 21) in the range of 6 to 16% relative to the circumferential dimension of the rotating shaft 900, a significant oil supply reduction effect can be achieved. This allows the oil film area to be filled with oil with a relatively small amount of oil supply, effectively suppressing unstable vibrations. Furthermore, by limiting the opening ratio to the range of 8 to 16%, a more stable and significant oil supply reduction effect can be achieved.

[0056] Implementation method 3.

[0057] A journal bearing according to a third embodiment will be described. Figure 10 This figure shows the structure of the oil supply nozzle 30 and the surroundings of the journal bearing 100 according to this embodiment. Figure 3 The shape of the opening surface 21a2 of the upstream pad 21 of the embodiment 1 is changed, and the description of the same structure as that of the embodiment 1 is omitted. Figure 10 As shown, the inclined surface is provided so that a tangent line 21a20 of the opening surface 21a2 at a position where the front end surface 21c and the opening surface 21a2 are connected passes through the bubble discharge path 40 (including the boundary surface).

[0058] According to this structure, the bubble discharge path 40 through which the tangent line 21a20 of the opening surface 21a2 passes can be ensured. Therefore, the bubbles 801 flowing upstream along the opening surface 21a2 can be efficiently guided to the bubble discharge path 40 without being blocked by the oil distribution portion 301 .

[0059] Implementation method 4.

[0060] A journal bearing according to a fourth embodiment will be described. Figure 11 This figure shows the structure of the oil supply nozzle 30 and the surroundings of the journal bearing 100 according to this embodiment. Figure 3Detailed cross-sectional view of portion C. In addition, the shape of the opening surface 21a2 of the upstream pad 21 of the first embodiment is changed, and the description of the same structure as that of the first embodiment is omitted.

[0061] like Figure 11 As shown, opening surface 21a2 is composed of multiple inclined or curved surfaces. Among the inclined or curved surfaces, opening surface 21a23, which forms the smallest angle with partial cylindrical surface 21a1, is located furthest downstream of the plurality of inclined or curved surfaces. Specifically, the angle formed between a tangent line to the inclined or curved surface and a tangent line to the outer peripheral surface of rotating shaft 900 at a position radially facing the tangent line is smallest at the rearmost position of opening surface 21a2 in the direction of rotation of rotating shaft 900.

[0062] According to this structure, the bubbles 801 flowing upstream along the opening surface 21a23 can be efficiently discharged to the outer diameter side through the bubble discharge path 40 without being blocked by the opening surfaces 21a22 and 21a21 on the upstream side.

[0063] Implementation method 5.

[0064] A journal bearing according to a fifth embodiment will be described. Figure 12 This is a diagram showing the structure of the journal bearing of this embodiment. Figure 2 In addition, the description of the same structure as that of the embodiment 1 is omitted.

[0065] like Figure 12 As shown, the minimum axial outer dimension a of the oil supply port 302 in the oil supply nozzle 30 is set to be less than half the maximum axial outer dimension b of the oil distribution portion 301. That is, the relationship a<b / 2 is achieved.

[0066] According to this structure, a sufficient flow path is ensured between the carrier ring 10 and the oil distribution part 301 . Therefore, the bubbles 801 passing through the bubble discharge path 40 can be more efficiently discharged to the atmosphere vertically above through the flow path between the carrier ring 10 and the oil distribution part 301 by buoyancy.

[0067] Implementation method 6.

[0068] A journal bearing according to a sixth embodiment will be described. Figure 13 This is a diagram showing the structure of the journal bearing of this embodiment. Figure 2 The shape of the oil supply nozzle 30 of the first embodiment is changed, and the description of the same structure as that of the first embodiment is omitted.

[0069] like Figure 13 As shown, the oil supply port 302 connecting the oil distribution portion 301 and the carrier ring 10 in the oil supply nozzle 30 is arranged outside the axial center of the oil distribution portion 301, for example, at both axial ends.

[0070] This structure ensures a flow path between the oil distribution portion 301 and the carrier ring 10 at the axial center of the oil distribution portion 301. Therefore, bubbles 801 passing through the bubble discharge path 40 can be more efficiently discharged into the atmosphere vertically above through the flow path between the carrier ring 10 and the oil distribution portion 301, utilizing buoyancy. The oil film pressure supporting the rotating shaft 900 is highest at the axial center of the partial cylindrical surface 21a1. Therefore, by specifically suppressing the intrusion of bubbles 801 at the axial center, unstable vibrations can be more effectively suppressed.

[0071] Furthermore, according to this embodiment, since the oil within the oil distribution portion 301 flows from the oil supply ports 302 at the axial ends toward the axial center, the flow of oil supplied through the oil supply hole 301a also includes a velocity vector directed from the axial ends toward the axial center. This allows the amount of oil supplied to the axial center to be relatively increased, allowing the oil film region at the axial center, where the oil film pressure is high, to be filled with oil with a relatively small amount of oil supply, thereby more effectively suppressing unstable vibrations.

[0072] Furthermore, in this embodiment, the oil supply port 302 is disposed at both axial ends of the oil distribution portion 301. However, if the oil supply port 302 is disposed at only one end, a wider flow path can be ensured between the oil distribution portion 301 and the carrier ring 10, thereby more efficiently discharging the air bubbles 801 into the atmosphere. In other words, the intrusion of the air bubbles 801 can be more effectively suppressed, thereby suppressing unstable vibrations.

[0073] Implementation method 7.

[0074] A journal bearing according to a seventh embodiment will be described. Figure 14 This is a diagram showing the structure of the journal bearing of this embodiment. Figure 2 The shape of the oil supply nozzle 30 of the first embodiment is changed, and the description of the same structure as that of the first embodiment is omitted.

[0075] like Figure 14 As shown, the oil distribution portion 301 is not provided with the oil supply port 302 but is directly connected to the two side plates 50 surrounding the downstream pad 20 and the upstream pad 21 in the axial direction.

[0076] This structure ensures a flow path between the oil distribution portion 301 and the carrier ring 10 at all axial positions of the oil distribution portion 301, thereby more efficiently discharging the bubbles 801 into the atmosphere. In other words, the intrusion of the bubbles 801 can be more effectively suppressed, thereby suppressing unstable vibrations.

[0077] In the present embodiment, the oil distribution portion 301 is connected to two side plates 50 , but the same effect can be achieved even if the oil distribution portion 301 is connected to only one side plate 50 .

[0078] Implementation method 8.

[0079] The rotating device of the eighth embodiment will be described. Figure 15 1 is a cross-sectional view showing a structure of the rotary device 1000 according to the present embodiment cut along the axial direction. Figure 15 The up and down directions in , for example, represent the vertical up and down directions. Figure 15 As shown, a rotating device 1000 includes a horizontally arranged rotating shaft 900, a pair of journal bearings 100 rotatably supporting both ends of the rotating shaft 900, and a stator 901 provided on the outer circumference of the rotating shaft 900. At least one of the pair of journal bearings 100 is the journal bearing of any one of the first to seventh embodiments.

[0080] Journal bearings 100 are each provided on the outer circumference of an end portion of the rotating shaft 900. Each journal bearing 100 supports the radial load of the rotating shaft 900, including the weight of the rotating shaft 900. The rotating shaft 900 includes a rotor 900a having magnetic poles. In this embodiment, a rotating electrical machine is exemplified as the rotating device 1000, in which a stator 901 induces an AC voltage to generate electricity.

[0081] According to this embodiment, the bearing loss generated in the journal bearing 100 relative to the energy of the rotating shaft 900 can be reduced, thereby improving the power generation efficiency of the rotating electrical machine. In addition, since the amount of oil supplied to the journal bearing 100 can be reduced, the oil supply equipment such as the oil pump 902 can be miniaturized.

[0082] In the journal bearing 100 of any one of the above-mentioned embodiments 1 to 8, the number of the oil supply nozzles may be two or more. Figure 2 Configuration location shown.

[0083] In the journal bearing 100 according to any one of the first to eighth embodiments, the shape and arrangement of the flow path for supplying oil to the oil supply port 302 are not limited.

[0084] In the journal bearing 100 according to any of the first to eighth embodiments, the opening surface 21a2 may be provided in the downstream pad 20, and the oil distribution portion 301, oil supply hole 301a, and bubble discharge path 40 may be provided upstream of the downstream pad 20. This arrangement allows the oil film thickness to be increased by positioning the oil at positions bilaterally symmetrical with respect to the axis of the rotating shaft 900. Furthermore, when oil in the gap between the inner circumferential surface 21a of the upstream pad 21 and the outer circumferential surface of the rotating shaft 900 escapes from the gap in the rotational direction, cavitation (gas bubbling) may occur due to a sudden drop in pressure. However, this prevents the gas generated by cavitation from flowing into the gap between the inner circumferential surface of the downstream pad 20 and the outer circumferential surface of the rotating shaft 900 as the rotating shaft 900 rotates.

[0085] In the journal bearing 100 according to any of the first to eighth embodiments, the downstream pad 20 and the upstream pad 21 may have a single-layer structure formed of a single material or a multi-layer structure formed of multiple materials. Various materials such as metal and resin may be used to form the downstream pad 20 and the upstream pad 21.

[0086] In the journal bearing 100 of any one of the first to eighth embodiments, the downstream pad 20 and the upstream pad 21 may have a constant axial width throughout the entire circumference, or may have different axial widths depending on the circumferential position.

[0087] The journal bearing 100 according to any one of the first to eighth embodiments further includes a state in which the lubricating oil 800 is not supplied to the interior of the journal bearing 100 .

[0088] In the journal bearing 100 of any one of the above-mentioned embodiments 1 to 8, the shape of the oil distribution portion 301 of the oil supply nozzle 30 is not limited to a cylindrical shape. As long as the cross-sectional shape is an elliptical or polygonal shape that can form a bubble discharge path 40 through the flow of the lubricating oil 800, the same effect can be obtained in other shapes.

[0089] In the present specification, expressions indicating directions such as “axial direction”, “radial direction”, “circumferential direction”, “rotational direction”, and “vertical direction” include not only such directions in a strict sense but also directions that can achieve substantially the same function.

[0090] In this specification, expressions such as "decreasing toward the downstream side" indicating a change in length or number are not limited to a monotonically decreasing state and include a state of decreasing only within a certain range, a state of varying decreasing rates within each range, and a state of decreasing in stages. The same applies to expressions such as "increasing toward the downstream side."

[0091] In the present specification, expressions such as “having”, “equipped with”, “including”, and “having” are not exclusive expressions excluding the presence of other constituent elements.

[0092] This application describes various illustrative embodiments and examples, but the various features, methods, and functions described in one or more embodiments are not limited to the application of specific embodiments and can be applied to the embodiments alone or in various combinations. Therefore, within the scope of the technology disclosed in this application specification, countless unillustrated variations are envisioned. For example, this includes the case where at least one component is modified, added, or omitted, and the case where at least one component is extracted and combined with components of other embodiments.

[0093] Description of Reference Numerals

[0094] 10 load ring, 20 downstream pad, 21 upstream pad, 21a inner circumferential surface, 21a1 partial cylindrical surface, 21a2 opening surface, 21a20 tangent line, 21a21 opening surface, 21a22 opening surface, 21a23 opening surface, 21b outer circumferential surface, 21c front end surface, 30 oil supply nozzle, 301 oil distribution part, 301a oil supply hole, 302 oil supply port, 3011 outer wall surface, 40 bubble discharge path, 50 side plate, 100 journal bearing, 800 lubricating oil, 801 bubbles, 900 rotating shaft, 900a rotor, 901 stator, 902 oil supply pump, 1000 rotating equipment.

Claims

1. A journal bearing, which supports a rotating shaft of a rotating device, characterized in that: have: an oil supply nozzle having an oil distribution portion extending in the axial direction of the rotating shaft and supplying lubricating oil; and a pad provided at the rear of the rotating shaft of the oil supply nozzle in the rotation direction and supporting the rotating shaft so as to be rotatable, The inner peripheral surface of the pad facing the outer peripheral surface of the rotating shaft has an opening surface in which the radial distance between the inner peripheral surface and the outer peripheral surface of the rotating shaft decreases from the front end surface of the pad in the rotation direction of the rotating shaft toward the rear in the rotation direction. A bubble discharge path for discharging bubbles mixed in the lubricating oil is provided between the oil distribution portion and the pad.

2. The journal bearing according to claim 1, wherein: The angle of the circumferential dimension of the opening surface relative to the circumferential dimension of the inner circumferential surface of the pad in the circumferential direction of the rotating shaft is in a range of 6 to 16%.

3. The journal bearing according to claim 1 or 2, characterized in that: The opening surface of the pad is provided so that a tangent line at a position where the opening surface contacts the front end surface passes through the air bubble discharge path.

4. The journal bearing according to claim 1 or 2, characterized in that: The opening surface of the pad has a curved surface shape, and the curved surface shape is a shape in which the angle between the tangent of the opening surface and the tangent of the outer peripheral surface of the rotating shaft at a position radially facing the tangent point relative to the tangent decreases from the front end surface in front of the rotation direction of the rotating shaft of the pad toward the rear.

5. The journal bearing according to claim 1 or 2, characterized in that: The opening surface of the pad has multiple inclined surfaces or curved surfaces, and the angle between the tangent of the inclined surface or the curved surface and the tangent of the outer peripheral surface of the rotating shaft at a position radially opposite to the tangent point of the tangent is smallest at the rear end of the rotation direction of the rotating shaft of the opening surface.

6. The journal bearing according to claim 1 or 2, characterized in that: A minimum axial outer dimension of an oil supply port for supplying the lubricating oil to the oil distribution portion of the oil supply nozzle is equal to or smaller than a half of a maximum axial outer dimension of the oil distribution portion.

7. The journal bearing according to claim 1 or 2, characterized in that: An oil supply port for supplying the lubricating oil to the oil distribution portion of the oil supply nozzle is provided at a position outside the axial center of the oil distribution portion.

8. The journal bearing according to claim 1 or 2, characterized in that: The oil supply nozzle directly supplies the lubricating oil to the oil distribution portion without providing an oil supply port.

9. A rotating device using a journal bearing, wherein the rotating device supports a rotating shaft through the journal bearing, characterized in that: The journal bearing comprises: an oil supply nozzle having an oil distribution portion extending in the axial direction of the rotating shaft and supplying lubricating oil; and a pad provided at the rear of the rotating shaft of the oil supply nozzle in the rotation direction and supporting the rotating shaft so as to be rotatable, The inner peripheral surface of the pad facing the outer peripheral surface of the rotating shaft has an opening surface in which the radial distance between the inner peripheral surface and the outer peripheral surface of the rotating shaft decreases from the front end surface of the pad in the rotation direction of the rotating shaft toward the rear in the rotation direction. A bubble discharge path for discharging bubbles mixed in the lubricating oil is provided between the oil distribution portion and the pad.

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