JP2013124674A - Sliding bearing and pump device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a load carrying capacity and bearing rigidity of a bearing without increasing the size of the bearing and the pressure of a fluid externally supplied, in a journal bearing type sliding bearing having a hydrostatic bearing structure that supports rotational motion of a shaft by externally supplying a high-pressure fluid to a gap between the outer periphery of the shaft and the inner periphery of a substantially cylindrical bearing.SOLUTION: The sliding bearing comprises: a substantially cylindrical sleeve the inner periphery of which slides via a fluid on a rotatable shaft outer periphery; a hydrostatic pressure supply passage penetrating the sleeve and supplying a high-pressure fluid from an external pressure source into the inner periphery of the sleeve; and a hydrostatic pressure pocket which has a recessed shape in a radial direction on the inner periphery of the sleeve, and where the hydrostatic pressure supply passage is open via an orifice. At least one row of hydrostatic pressure pockets where a plurality of hydrostatic pressure pockets are circumferentially arranged, is formed in the vicinity of each of both ends of the sleeve inner periphery in the axial direction of the shaft. A cylindrical inner peripheral region having no hydrostatic pressure pocket is formed in the center part of the sleeve, while being interposed by the hydrostatic pressure pocket rows, with a broader width in the shaft axial direction than the sum of widths of the hydrostatic pressure pocket rows.

Description

  The present invention relates to a slide bearing having a hydrostatic bearing structure that supplies a high-pressure fluid from the outside to a gap between a shaft outer periphery and a substantially cylindrical sleeve inner periphery to support the rotational motion of the shaft, and an impeller by the slide bearing. It is related with the pump apparatus provided with the mechanism which supports the rotational motion of the shaft connected to.

  For large pump devices used for circulating cooling systems in fast breeder reactors, fluids such as fluid metal that is a cooling medium are generally transferred by rotating an impeller attached to a long shaft in a casing. A mechanical longitudinal pump device is used. In this pump device, a journal bearing is provided in the vicinity of the impeller of the shaft for the purpose of preventing the impeller from colliding with the casing or the like due to a swing or an earthquake and suppressing the vibration of the shaft. A slide bearing is often used as the journal bearing, and the rotational movement of the shaft is supported by sliding the outer circumference of the shaft while being lubricated with the inner circumference of the substantially cylindrical sleeve of the slide bearing through the fluid.

  In a slide bearing used in such a pump device, the clearance between the outer periphery of the shaft and the inner periphery of the bearing can be secured larger than that of a normal slide bearing in order to allow thermal deformation and manufacturing errors of the shaft and casing. Desired. Also, the fluid that can be used for sliding bearing lubrication is limited to the same type of fluid that is transported by a pump for the purpose of preventing foreign substances from being mixed in. The pump device for fast breeder reactors uses low-viscosity fluid metals, etc. Desired.

  Due to these circumstances, the plain bearing used in the pump device is in a condition in which it is difficult to obtain a large dynamic pressure as it is as compared with an oil-lubricated plain bearing used in a general mechanical device. Therefore, even under these conditions, in order to stably support the shaft against a high load, a hydrostatic bearing structure in which high-pressure fluid is introduced into the sliding surface from the outside of the bearing and used to support the load is often employed. ing.

  In general, in a journal bearing type slide bearing having a hydrostatic bearing structure, a plurality of concave portions called hydrostatic pockets are provided in the circumferential direction or shaft axial direction on the inner circumference of a substantially cylindrical sleeve, and most of the inner circumference of the sleeve is provided. The area is occupied by a static pressure pocket. In each static pressure pocket, a passage communicating from an external pressure source is opened. The high-pressure fluid introduced into the static pressure pocket from the external pressure source through the passage fills the gap between the bearing and the shaft inside the static pressure pocket and flows out from the open end of the gap to the outside of the low pressure. When the shaft is pushed in the radial direction by the load and is eccentric in the bearing, the gap is partially biased, so the outflow of the gap in the eccentric direction decreases and the pressure in that part rises. The amount of outflow in the gap on the opposite side increases and the pressure in that part decreases. Due to the pressure difference between them, a restoring force is generated to return the shaft to the center of the bearing, thereby supporting the shaft load.

  In recent years, with an increase in capacity of a pump device, improvement in bearing capacity, which is a load capacity that can be supported by a slide bearing, and a change in load capacity with respect to a minimum gap change due to shaft eccentricity has been an issue.

  As a background art of this technical field, Patent Document 1 discloses that in a hydrostatic bearing having a pocket on the inner peripheral surface of the bearing and high pressure oil is supplied between the pocket and the outer peripheral surface of the rotary shaft, the pocket is circular. There is described a hydrostatic bearing in which a plurality of pocket rows formed in the circumferential direction are formed in a plurality of rows in the axial direction and the phases of the pockets between the rows are shifted in the circumferential direction.

  According to Patent Document 1, a plurality of pocket rows formed with a plurality of static pressure pockets in the circumferential direction are formed in the axial direction, and the shaft is eccentric in a certain radial direction by shifting the phase of the pockets between the rows in the circumferential direction. When this occurs, the force acting in the radial direction perpendicular thereto is offset, and it is expected that the stability of the bearing will be improved during high-speed rotation.

  However, even if the phases of the static pressure pockets are shifted in the circumferential direction and only a plurality of rows are formed in the axial direction as in Patent Document 1, there is almost no effect on the load capacity and bearing rigidity of the bearing, and the pressure of the oil supplied from the outside It has been difficult to increase the load capacity without increasing the load or increasing the size of the bearing.

  Further, in Patent Document 2, an impeller shaft bearing is provided in the immediate vicinity of an impeller provided between a suction port and a discharge port in a casing, and a plurality of pockets are arranged in the circumferential direction on the inner surface of the bearing. In the pump that introduces a part of the fluid metal to be pumped into the pocket, the circumferential direction in which the fluid metal is contained in the annular band provided so as to rotate relative to the pocket in the axial direction with a liquid sealing property A fluid metal pump provided with a concave groove is described. In addition, a ring-shaped cavity in the circumferential direction always containing fluid metal is attached to an annular band portion having a liquid sealing property provided with pockets constituting an hydrostatic bearing supporting the impeller in the axial direction. Is described.

  According to Patent Document 2, the metal between the shaft and the bearing is formed by the structure in which the circumferential groove is provided in the annular belt portion provided so as to sandwich the static pressure pocket supplied with the high-pressure fluid metal from the outside in the axial direction. Even when contact occurs, fluid metal is easily supplied to the periphery of the contact portion, and reduction of damage due to galling or the like is expected due to the effect of lubrication and cooling.

  However, even if the circumferential groove is provided in the annular belt portion as in Patent Document 2, the change in the pressure distribution on the inner periphery of the bearing is small, and the effect of improving the load capacity and bearing rigidity of the bearing can hardly be expected. For this reason, it is difficult to increase the load capacity without increasing the pressure of oil supplied from the outside or increasing the size of the bearing.

  In Patent Document 3, a plurality of pressure generation zones are formed in the circumferential direction of the bearing surface that supports the axial load provided on the bearing member fixed to the rotatable shaft member. Each of them is separated from each other in the axial direction and formed with a static pressure generating part consisting of a pair of pockets having a discharge mechanism, a dynamic pressure generating part consisting of a land part formed between both pockets, and parallel to the axis of both pockets. And has a supply groove that connects both pockets to each other and supplies pressure fluid to both pockets via a restriction, and generates dynamic pressure more than the bearing clearance of the static pressure generator. Describes a hydrodynamic bearing device in which the bearing clearance of the part is reduced.

  According to Patent Document 3, in addition to the static pressure generated by supplying the pressure fluid introduced into the external supply groove to the pocket, generation of dynamic pressure is also expected in the dynamic pressure generating portion surrounded by the pocket and the supply groove. it can.

  However, in Patent Document 3, even if a dynamic pressure higher than that of the external pressure fluid is generated in the dynamic pressure generating portion, the pressure easily escapes through the supply groove, and support by the dynamic pressure is limited. For this reason, the load capacity largely depends on the static pressure. Further, when a gap in a certain portion becomes wide due to deformation or inclination of the shaft and the amount of fluid flowing out from the portion increases, the pressure in the communicating pocket and the entire supply groove decreases, and the load capacity tends to decrease. In the above vertical pump device, in most cases, the shaft rotates in an inclined posture with respect to the inner periphery of the bearing. For this reason, the configuration of the patent document is difficult to apply to a vertical pump or the like.

JP-A-61-236921 Japanese Unexamined Patent Publication No. 57-200699 JP-A-60-37329

  The present invention has been made in view of the above circumstances, and a hydrostatic bearing structure that supplies a high-pressure fluid from the outside to the gap between the outer periphery of the shaft and the inner periphery of the substantially cylindrical bearing to support the rotational movement of the shaft. This is a journal bearing type slide bearing equipped with a pump and a pump device containing the same, increasing the dynamic pressure generated in the clearance when the shaft rotates, and making the best use of the bearing size and fluid supplied from the outside It is a technical problem to be solved to increase the load capacity and bearing rigidity of the bearing without increasing the pressure of the bearing.

  The present invention relates to a substantially cylindrical sleeve that is slidably supported on a rotatable shaft through a fluid at its inner periphery, and a static pressure that passes through the sleeve and supplies a high-pressure fluid from an external pressure source to the sleeve inner periphery. A static pressure pocket in which a plurality of static pressure pockets are arranged in the circumferential direction in a slide bearing having a supply passage and a static pressure pocket provided in the inner periphery of the sleeve and having a concave shape in the radial direction and opening the static pressure supply passage. At least one row is formed in the vicinity of both ends in the shaft axial direction of the inner circumference of the sleeve, and a cylindrical inner circumferential surface area is formed in the center portion of the sleeve and is sandwiched between the static pressure pocket rows and has no static pressure pockets. It is characterized by.

  Further, the slide bearing is characterized in that the width in the shaft axial direction of the cylindrical inner peripheral surface region where no static pressure pocket exists is provided larger than the total width in the shaft axial direction of the static pressure pocket row.

  In a plain bearing, a static pressure supply passage that communicates with a static pressure pocket belonging to the same static pressure pocket row and a static pressure supply passage that communicates with a static pressure pocket belonging to a different static pressure pocket row are independent of each other. It is characterized in that it communicates with a pressure source that supplies fluid.

  Further, the slide bearing is characterized in that the installation angle range of the static pressure pocket extending in the circumferential direction overlaps with the installation angle range of another adjacent static pressure pocket.

  Further, the slide bearing is characterized in that the installation angle range of the static pressure pockets extending in the circumferential direction overlaps with the installation angle range of other adjacent static pressure pockets.

  Further, in the slide bearing, the static pressure pocket extends to the upstream side in the rotation direction of the shaft from the outside near the sleeve end to the sleeve end, and from the inside far from the sleeve end to the sleeve end. It has the shape extended | stretched in the downstream of the shaft rotation direction rather than the near outer side.

  Further, the slide bearing is characterized in that a groove where the static pressure supply passage does not open is provided in a region where no static pressure pocket exists on the inner periphery of the sleeve.

  Furthermore, an impeller that is arranged in the middle of the fluid flow path and transfers the fluid by rotational movement, a shaft that is connected to a rotational power source and rotationally drives the impeller, and a substantially cylinder that supports the outer peripheral surface of the shaft by sliding through the fluid. A sleeve having a shape, a static pressure supply passage that passes through the sleeve and supplies high-pressure fluid from the discharge side of the fluid flow path to the inner periphery of the sleeve, and a static pressure supply that is provided on the inner periphery of the sleeve and has a concave shape in the radial direction. In the pump apparatus having a slide bearing having a static pressure pocket having an open passage, at least one row of static pressure pockets in which a plurality of static pressure pockets are arranged in the circumferential direction is provided in the vicinity of both ends of the sleeve inner circumference in the shaft axial direction. A cylindrical inner peripheral surface region that is formed and that is sandwiched between the static pressure pocket rows and does not have a static pressure pocket is provided at the center of the sleeve.

  Further, the pump device is characterized in that the width in the shaft axial direction of the cylindrical inner peripheral surface region is larger than the total width of the static pressure pockets in the shaft axial direction.

  Furthermore, in the pump device, the static pressure supply passage that communicates with the static pressure pocket belonging to one static pressure pocket row and the static pressure supply passage that communicates with the static pressure pocket belonging to the other static pressure pocket row are independent of each other. It leads to the discharge side of the road.

  Furthermore, in the pump device, the fluid flowing in the fluid flow path is a fluid metal.

  The present invention relates to a substantially cylindrical sleeve that is slidably supported on a rotatable shaft through a fluid at its inner periphery, and a static pressure that passes through the sleeve and supplies a high-pressure fluid from an external pressure source to the sleeve inner periphery. A static pressure pocket in which a plurality of static pressure pockets are arranged in the circumferential direction in a slide bearing having a supply passage and a static pressure pocket provided in the inner periphery of the sleeve and having a concave shape in the radial direction and opening the static pressure supply passage. At least one row is formed in the vicinity of both ends in the shaft axial direction of the inner circumference of the sleeve, and a cylindrical inner circumferential surface area is formed in the center portion of the sleeve and is sandwiched between the static pressure pocket rows and has no static pressure pockets. As a result, the shaft rotating on the inner circumference of the sleeve is supported by the static pressure supplied from the outside to the static pressure pocket and the dynamic pressure generated between the cylindrical inner peripheral surface area, and dynamic pressure is generated. Obtained great pressure as compared with the conventional example, it is possible to increase the load capacity and bearing rigidity of the entire plain bearing.

It is a block diagram of the vertical pump apparatus of Example 1 of this invention. It is an enlarged view of a slide bearing periphery in the vertical pump device according to the first embodiment of the present invention. It is a perspective view of the sleeve in the slide bearing of Example 1 of this invention. It is a graph which shows the load capability in the slide bearing of Example 1 of this invention. It is a graph which shows the bearing rigidity in the slide bearing of Example 1 of this invention. It is sectional drawing of the slide bearing Example of Example 2 of this invention. It is sectional drawing of the plain bearing of Example 3 of this invention. It is sectional drawing of the plain bearing of Example 4 of this invention. It is sectional drawing of the plain bearing of Example 5 of this invention. It is sectional drawing of the plain bearing of Example 6 of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  In the first embodiment, a vertical pump device 100 incorporating a journal bearing type slide bearing according to the present invention will be described.

  FIG. 1 is a configuration diagram of a vertical pump device 100 according to the present embodiment. A flow path 104 communicating from the suction port 102 to the discharge port 103 is formed in the casing 101. An impeller 105 is provided in the middle of the flow path 104 at the tip of a shaft 106 connected to an external rotational power source 107.

  The shaft 106 is rotatably supported by a bearing 108 on one rotational power source 107 side, and is rotatably supported by a sliding bearing 109 on the other impeller 105 side. When the shaft 106 is rotated by the power supply from the rotational power source 107 and the impeller 105 is rotated, fluid such as fluid metal that has flowed into the pump device 100 from the suction port 102 is transferred through the flow path 104 and discharged. It is discharged to the outside from the outlet 103. A pressure head is generated on the downstream side of the impeller 105 of the flow path 104 as compared with the upstream side, and the pressure on the downstream side becomes higher.

  Of the two bearings, the bearing 108 rotatably supports the shaft 106, and also supports a load in the vertical direction of FIG. 1, that is, the axial direction of the shaft 106. On the other hand, the sliding bearing 109 is fixed to the support portion 110 to prevent the shaft 106 from swinging in the radial direction to prevent the impeller 105 from colliding with the wall surface of the flow path 104, the casing 101, and the like. The vibration caused by the rotational movement 105 is suppressed.

  FIG. 2 is an enlarged view around the slide bearing 109. In the slide bearing 109, a plurality of static pressure pockets 112A having a concave shape in the radial direction are formed on the inner periphery of a substantially cylindrical sleeve 111A. In each static pressure pocket 112 </ b> A, a static pressure supply passage 113 penetrating the support portion 110 and the sleeve 111 </ b> A from the discharge side of the flow path 104 is opened through an orifice 114. As a result, a part of the high-pressure fluid transferred to the downstream side of the flow path 104 by the rotation of the impeller 105 is introduced into the static pressure pocket 112A through the static pressure supply path 113 and the orifice 114, and the outer periphery of the shaft 106 and the sleeve The gap on the inner periphery of 111A is filled.

  The static pressure pocket 112A has a plurality of static pressure pockets 112A arranged in the circumferential direction on the inner periphery of the sleeve 111A to form a static pressure pocket row. One row of static pressure pockets is provided in the vicinity of both end portions in the axial direction of the shaft 106 on the inner periphery of the sleeve 111A. In addition, a cylindrical inner peripheral surface region 115 where no static pressure pocket row exists is provided between the static pressure pocket rows at the center of the inner periphery of the sleeve 111A.

  FIG. 3 is a perspective view showing details of the sleeve 111A. On the inner periphery of the sleeve 111A, a row of static pressure pockets 116 in which a plurality of static pressure pockets 112A are arranged in the circumferential direction is provided in the vicinity of both ends of the sleeve 111A, whereas the outer periphery of the sleeve 111A has a static pressure supply passage. 113 is provided. The static pressure supply passage 113 communicated with one of the static pressure pocket rows 116 and the static pressure supply passage 113 communicated with the other static pressure pocket row are provided independently, and each is individually provided as shown in FIG. It communicates with the downstream side of the flow path 104.

  The inventor constituted the plain bearing according to the present invention, evaluated the load capacity and the bearing rigidity, verified the effect of improving the load capacity and the bearing rigidity by applying the present invention, and effectively reduced the load and reduced the bearing rigidity. The relationship between the static pressure pockets 112 </ b> A that can be improved and the cylindrical inner peripheral surface region 115 sandwiched between the static pressure pocket rows 116 is examined. The results will be described next with reference to FIGS.

  FIG. 4 shows the load capacity of the bearing when the pressure of the fluid supplied to the static pressure pocket 112A is constant and the width of the static pressure pocket 112A and the width of the cylindrical inner peripheral surface region 115 are changed in the inner periphery of the sleeve 111A. . When the width of the cylindrical inner peripheral surface region 115 is larger than the total width of the static pressure pocket rows 116 provided on both sides of the cylindrical inner peripheral surface region 115, the load capacity of the bearing is smaller than that in the case of less than that. The increase rate was particularly improved.

  FIG. 5 shows an example of bearing rigidity when the pressure of the fluid supplied to the static pressure pocket 112A is constant and the width of the static pressure pocket 112A and the width of the cylindrical inner peripheral surface region 115 in the inner periphery of the sleeve 111A are changed. . When the width of the cylindrical inner peripheral surface region 115 becomes larger than the sum of the widths of the static pressure pocket rows 116 provided on both sides of the cylindrical inner peripheral surface region 115, the bearing rigidity increase rate is smaller than that in the case where the width is smaller than that. Was particularly improved.

  As described above, in forming the static pressure pocket row 116 provided in the vicinity of both ends of the inner periphery of the sleeve 111A and the cylindrical inner peripheral surface region 115 sandwiched between the rows, the cylindrical inner peripheral surface region 115 in the axial direction of the shaft 106 is formed. It has been verified that the load capacity and the bearing rigidity can be increased even more effectively by making the width larger than the total width of the static pressure pocket rows 116 sandwiching the width.

  The main purpose of providing the static pressure pocket row in the vicinity of both ends of the sleeve inner periphery is to maintain a high pressure at both ends of the cylindrical inner surface region located between the static pressure pocket rows and The purpose is to maintain the generated dynamic pressure level.

  FIG. 6 shows a second embodiment of a sleeve portion of a plain bearing for more reliably achieving this object. Two static pressure pocket rows 116 are provided in the vicinity of both ends of the inner periphery of the sleeve 111B, and the static pressure pockets 112B are alternately arranged in the circumferential direction in two adjacent static pressure pocket rows 116.

  A cylindrical inner peripheral surface region 115 where the static pressure pocket 112B does not exist is formed at the inner peripheral central portion of the sleeve 111B. The width of the cylindrical inner peripheral surface region 115 in the axial direction of the shaft 106 is opposite to the cylindrical inner peripheral surface region 115. It is larger than the width of a total of four rows of static pressure pockets 116 sandwiched therebetween.

  By adopting such a configuration, the static pressure pockets 112B belonging to the other adjacent static pressure pocket rows 116 are positioned at circumferential angular positions where no static pressure pockets exist in one static pressure pocket row 116. Thus, the supply of static pressure by the static pressure pocket 112B is continuously and uniformly performed all around the both ends of the sleeve 111B. As a result, the pressure in the cylinder inner peripheral surface region 115 is maintained at a higher level, and a high load capacity and bearing rigidity can be obtained as a slide bearing.

  FIG. 7 shows a third embodiment of the sleeve portion of the plain bearing for increasing the pressure in the vicinity of both ends of the inner periphery of the sleeve 111C, that is, at both ends of the cylindrical inner peripheral surface region 115. The static pressure pocket 112C has an asymmetric shape in the circumferential direction and the axial direction of the shaft 106, and a static pressure pocket extension 117 is partially provided at the circumferential end of the static pressure pocket 112C. The static pressure pocket extension 117 is separated from the static pressure pocket extension 117 of the other static pressure pockets 112C adjacent in the circumferential direction, but partially overlaps in a constant installation angle range in the circumferential direction.

  The static pressure pocket 112C is formed with a static pressure pocket extension 117 extending upstream in the rotation direction 118 of the shaft 106 on the outer side near the end of the sleeve 111C, and on the inner side far from the end of the sleeve 111C, on the downstream side. A static pressure pocket extension 117 is formed extending in the vertical direction.

  By adopting such a configuration, the supply of static pressure by the static pressure pocket 112C is continuously and uniformly performed on the entire circumference of both ends of the sleeve 111C. Thereby, it is possible to maintain a high pressure in the cylindrical inner peripheral surface region 115 and obtain a high load capacity and bearing rigidity as a slide bearing.

  Furthermore, since it is only necessary to form a static pressure pocket extension 117 by processing a small region at the circumferential end of the static pressure pocket 112C, compared with the example of FIG. 6 in which a total of four static pressure pocket rows 116 are provided. Manufacturing costs are reduced.

  In addition, since the inside of the sleeve 111C of the static pressure pocket 112C extends on the downstream side in the rotation direction of the shaft 106, the fluid in the static pressure pocket 112C is pulled toward the center of the sleeve 111C as the shaft 106 rotates. A suction force to be applied acts, and a high pressure is easily held in the cylindrical inner peripheral surface region 115.

  Similarly, FIG. 8 shows a fourth embodiment of the sleeve portion of the plain bearing for increasing the pressure in the vicinity of both ends of the inner periphery of the sleeve 111D, that is, at both ends of the cylindrical inner peripheral surface region 115. Instead of forming the static pressure pocket extension 117 in the static pressure pocket 112D as in the example shown in FIG. 7, the static pressure pocket 112D is formed in a diamond shape. The static pressure pocket 112D is smoothly extended toward the upstream side in the rotational direction 118 of the shaft 106 toward the outer side closer to the end of the sleeve 111D, and the static pressure pocket 112D is positioned downstream in the circumferential direction toward the inner side farther from the end of the sleeve 111D. It is extended smoothly. By adopting such a structure, as compared with the example of FIG. 7, a suction force that tends to draw the fluid in the static pressure pocket 112D toward the center of the sleeve 111D as the shaft 106 rotates is more likely to act. Therefore, high pressure is easily held in the cylindrical inner peripheral surface region 115.

  FIG. 9 shows an example in which a foreign matter discharge groove 119 is formed in a portion where the static pressure pocket 112E does not exist on the inner peripheral surface of the sleeve 111E. The foreign matter discharge groove 119 is provided at a portion where the static pressure pocket 112E does not exist at both ends of the cylindrical inner peripheral surface region 115 and the sleeve 111E at the center of the sleeve 111E. The foreign matter discharge groove 119 is a groove that is recessed in the radial direction, different from the static pressure pocket 112E, and is a groove that the orifice 114 does not open.

  If foreign matter, wear particles, or the like flow into the gap between the outer periphery of the shaft 106 and the inner periphery of the sleeve 111E, the shaft 106 and the sleeve 111E may be worn and damaged. By adopting the structure as shown in FIG. 9, the discharge of foreign matters, wear particles, and the like that have flowed into the gap between the outer periphery of the shaft 106 and the inner periphery of the sleeve 111E is promoted.

  Since the orifice 114 does not open and the foreign matter discharge groove 119 is not in direct communication with the static pressure supply passage 113, the dynamic pressure generated in the cylindrical inner peripheral surface region 115 escapes through the static pressure supply passage 113 and is thus inside the cylinder. The effect of reducing the pressure in the peripheral surface region 115 is small.

  In addition, since the size of foreign matter and wear particles flowing into the gap between the outer periphery of the shaft 106 and the inner circumference of the sleeve 111E is the same size as the gap at the maximum, the depth of the foreign matter discharge groove 119 is about the same as the gap. good. For this reason, if the depth of the foreign matter discharge groove 119 is set to be about the same as the gap, even when the sleeve 111E is provided up to the end, the gap cross-sectional area at the end is small, and the pressure through this path is small. The escape can be reduced. As a result, it is possible to configure a highly reliable slide bearing that is less likely to damage the shaft 106 or the sleeve 111E due to foreign matter, wear particles, or the like while ensuring high load capability and bearing rigidity.

  FIG. 10 shows an example in which a groove 120 in which the orifice 114 does not open is formed in the cylindrical inner peripheral surface region 115. Each groove 120 has an outer side closer to the end of the sleeve 111F extending upstream in the rotation direction 118 of the shaft 106 and an inner side farther than the end of the sleeve 111F extending downstream in the rotation direction 118 of the shaft 106. Yes. With such a structure, the fluid flow is likely to be turbulent in the cylindrical inner peripheral surface region 115, or a suction force that tries to draw the fluid toward the center of the sleeve 111F as the shaft 106 rotates is generated. Since it becomes easier to act, the effect of generating dynamic pressure is enhanced.

  Further, by collecting foreign matter, wear particles, or the like in the groove 120, a highly reliable slide bearing can be configured with less risk of damage to the shaft 106 or the sleeve 111F due to foreign matter, wear particles, or the like.

  As is clear from the above embodiment, in the plain bearing according to the present invention, a predetermined cylindrical inner peripheral surface area is secured at the center of the sleeve inner periphery, and static pressure pocket rows are arranged at both ends of the sleeve across the sleeve. With this structure, the load capacity and bearing rigidity are improved by increasing the pressure in the cylinder inner peripheral surface region where dynamic pressure is generated when the shaft rotates and maintaining a higher pressure in the cylindrical inner surface region.

  In addition, a static pressure supply passage is provided independently at each end of the sleeve, and the pressure drop in a specific static pressure pocket row is reduced by connecting the pressure source separately to a pressure source capable of supplying a sufficient amount of high-pressure fluid. Even when the influence on the pocket row is limited and the shaft is inclined or deformed with respect to the inner periphery of the sleeve, high load capacity and bearing rigidity are ensured.

  In addition, the cylindrical inner peripheral surface region is sandwiched between the static pressure pocket rows whose pressure is higher than the open end of the sleeve in the shaft axial direction on the inner periphery of the sleeve, and the width of the cylindrical inner peripheral region is static in the shaft axial direction. By providing a pressure larger than the total width of the pressure pocket row, in addition to increasing the pressure in the cylindrical inner surface area during shaft rotation, the load capacity of the slide bearing is the pressure generated in the cylindrical inner surface area, especially when the shaft is eccentric. The ratio that depends on becomes larger. For this reason, the load capacity and bearing rigidity of the entire slide bearing can be improved without increasing the supply pressure from the outside, without narrowing the gap between the outer periphery of the shaft and the inner periphery of the sleeve, or without expanding the size of the sleeve. It can be increased effectively.

  In addition, a structure in which static pressure pocket rows are provided near both ends of the sleeve, the static pressure supply passages that lead to the sleeves are made independent of each other, and connected to a pressure source that can sufficiently supply high-pressure fluid, the shaft tilts in the sleeve. In addition to the moment force that pushes back the posture of the shaft, even if the gap in the specific part expands due to the inclination and the pressure drops in the surrounding static pressure pockets, other static pressure pocket rows are affected. Therefore, high load capacity and bearing rigidity can be secured even when the shaft is tilted.

  In addition, according to the pump device of the present invention, the pressure bearing is supplied to the static pressure pocket because it includes the slide bearing of the present invention and further supplies the pressure fluid to the static pressure pocket from the discharge side of the pump device. This eliminates the need for an additional pump device, and allows the system to be made compact.

  In addition, even if the clearance between the outer periphery of the shaft and the inner periphery of the sleeve is secured to some extent, or even if the shaft is inclined to some extent within the sleeve, a dynamic pressure higher than the fluid pressure supplied from the pump device to the static pressure pocket is cylindrical. It can be generated and held in the inner peripheral surface area. As a result, in a large-scale pump device that needs to stably support the rotational movement of the shaft against large thermal deformation, manufacturing error, etc., such as a vertical pump device used in a circulating cooling system of a fast breeder reactor. However, the bearing can ensure high load capacity and bearing rigidity, and high reliability can be ensured.

  For example, in a circulating cooling system of a fast breeder reactor, a fluid metal such as fluid sodium is often used as a cooling medium. In a pump device for transferring a fluid metal, it is desirable to use the same fluid metal for lubrication in order to prevent contamination of other substances. In general, fluid metals have a property that their viscosity becomes lower than that of general machine lubricating oil and water at high temperatures, and are inferior in lubricity. In addition, in the pump device, it is necessary to make the shaft that rotates the impeller long in order to provide a radiation shielding part, and in order to handle high-temperature fluid metal, a certain degree of shaft is caused by thermal deformation and manufacturing errors. Inclination and deformation are difficult to avoid.

  In the pump device according to the present invention, since the fluid having a high pressure by the impeller of the pump device is supplied to the static pressure pocket of the internal sliding bearing, there is no fear that other substances are mixed into the cooling medium in the pump device. In addition, a predetermined cylindrical inner peripheral surface area is secured at the center of the inner periphery of the sleeve in the slide bearing, and a structure in which static pressure pocket rows are arranged at both ends of the sleeve across the sleeve has a structure in which dynamic pressure is generated when the shaft rotates. By increasing the pressure in the peripheral surface region and maintaining a higher pressure in the inner peripheral surface region of the cylinder, it is possible to ensure a high load capacity and bearing rigidity even when using low-viscosity fluids such as fluid metals that are inferior in lubricity. . The load capacity of the slide bearing is highly dependent on the dynamic pressure especially when the shaft is eccentric, and it is not necessary to install a device for specifically increasing the pressure of the fluid supplied to the bearing outside in order to secure the load capacity. For this reason, the pump device can be configured in a simple and small size.

  Even when the gap between the outer periphery of the shaft and the inner periphery of the sleeve is relatively wide, or when the shaft is inclined or deformed with respect to the inner periphery of the sleeve, high load capacity and bearing rigidity are ensured. Therefore, thermal deformation, manufacturing errors, etc. are allowed, and stable shaft rotation is supported. In addition, since a static pressure pocket is installed near the end of the sleeve inner circumference, even if an excessive load acts on the shaft and the shaft inclined near the end of the sleeve inner circumference makes direct contact, Since the fluid from the hydrostatic pocket is supplied to the periphery thereof to cool and lubricate, damage due to wear and galling can be reduced.

100: pump device 101: casing 102: suction port 103: discharge port 104: flow path 105: impeller 106: shaft 107: rotational power source 108: bearing 109: slide bearing 110: support portions 111A to 111F: sleeves 112A to 112F: Static pressure pocket 113: Static pressure supply passage 114: Orifice 115: Cylindrical inner peripheral surface region 116: Static pressure pocket row 117: Static pressure pocket extension 118: Shaft rotation direction 119: Foreign matter discharge groove 120: Groove

Claims (11)

A substantially cylindrical sleeve that is slidably supported on the inner periphery of the rotatable shaft via a fluid, and a static pressure supply passage that passes through the sleeve and supplies high-pressure fluid from an external pressure source to the inner periphery of the sleeve. And a hydrostatic pocket provided on the inner periphery of the sleeve and having a concave shape in the radial direction and opening the hydrostatic supply passage,
At least one row of static pressure pockets in which a plurality of the static pressure pockets are arranged in the circumferential direction is formed in the vicinity of both end portions in the shaft axial direction of the inner periphery of the sleeve, and the static pressure pocket row is formed in the central portion of the sleeve. A plain bearing characterized in that a cylindrical inner peripheral surface region is provided which is sandwiched and does not have the static pressure pocket.   2. The plain bearing according to claim 1, wherein a width of the cylindrical inner peripheral surface area in which the static pressure pocket does not exist is greater than a total width of the static pressure pocket row in the shaft axial direction. A plain bearing characterized by   3. The slide bearing according to claim 1, wherein the static pressure supply passage communicates with the static pressure pocket belonging to the same static pressure pocket row and the static pressure pocket belonging to the different static pressure pocket row. The static pressure supply passage communicates with a pressure source that supplies a high-pressure fluid independently of each other, and the plain bearing is characterized in that   4. The slide bearing according to claim 1, wherein an installation angle range of the static pressure pocket extending in a circumferential direction overlaps with the installation angle range of another adjacent static pressure pocket. 5. A plain bearing.   4. The slide bearing according to claim 1, wherein an installation angle range of the static pressure pocket extending in a circumferential direction overlaps with an installation angle range of another adjacent static pressure pocket. 5. A plain bearing.   The slide bearing according to any one of claims 1 to 5, wherein the hydrostatic pocket extends on the upstream side in the rotation direction of the shaft at the outer side near the sleeve end portion than at the inner side far from the sleeve end portion. And a slide bearing having a shape in which an inner side far from the sleeve end extends to a downstream side in the shaft rotation direction than an outer side close to the sleeve end.   7. The plain bearing according to claim 1, wherein a groove where the static pressure supply passage does not open is provided in a region where the static pressure pocket does not exist on the inner periphery of the sleeve. Slide bearing. An impeller that is arranged in the middle of the fluid flow path to transfer fluid by rotational movement, a shaft that is connected to a rotational power source and rotationally drives the impeller, and a substantially cylinder that slidably supports the outer peripheral surface of the shaft via fluid. A sleeve having a shape, a static pressure supply passage that passes through the sleeve and supplies a high-pressure fluid from the discharge side of the fluid flow path to the inner periphery of the sleeve, and is provided in the inner periphery of the sleeve and has a concave shape in the radial direction. In the pump apparatus having a sliding bearing having a static pressure pocket in which the static pressure supply passage is opened,
At least one row of static pressure pockets in which a plurality of the static pressure pockets are arranged in the circumferential direction is formed in the vicinity of both ends in the shaft axial direction of the inner periphery of the sleeve, and the sleeve is sandwiched between the static pressure pocket rows at the center. A cylinder device is provided with a cylindrical inner peripheral surface area in which the static pressure pocket does not exist.   9. The pump device according to claim 8, wherein a width of the cylindrical inner peripheral surface region in the shaft axial direction is larger than a total width of the static pressure pockets in the shaft axial direction. Pump device.   The pump device according to claim 8 or 9, wherein a static pressure supply passage communicating with the static pressure pocket belonging to one of the static pressure pocket rows and a static pressure communicating with the static pressure pocket belonging to the other static pressure pocket row. The pump device characterized in that the pressure supply passages communicate with the discharge side of the fluid flow path independently of each other. 11. The pump device according to claim 8, wherein the fluid flowing in the fluid flow path is a fluid metal.

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