JP2005155894A - Fluid bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that as the rigidity of a member kept into contact with the fluid of high pressure among the members constituting a fluid bearing is not enough, the fluid bearing is deformed and can not retain its expected shape, and the allowable load of the bearing is lowered. <P>SOLUTION: Front and rear opposite discs 36, 38 are mounted in opposition to a rotary disc 26 rotated integrally with a shaft, through the rotary disc 26. The front opposite disc 36 has the shape to increase the pressure of the fluid with respect to the rotary disc 26, that is, has a radiation groove 50 and a pocket groove 52, and further is elastically supported by a spring 40 at its back face. As the rigidity of the front opposite disc 36 itself is sufficiently high, the deformation by the pressure generated in the fluid is not substantially generated. The displacement by whirling of the shaft and the rotary disc 26 is absorbed by the deformation of the spring 40, and a predetermined clearance is kept. Whereby the expected load can be achieved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fluid bearing that supports a member by the pressure of a fluid interposed between two members.

  A fluid bearing is known in which a space between two members is filled with a fluid, and one member is supported with respect to the other member by the pressure of the fluid. The hydrodynamic bearing includes a hydrostatic bearing that supplies a fluid whose pressure has been increased in advance between the members, and a fluid that flows by the relative movement of the two members so that the fluid is forced into a narrow part by the flow of the fluid itself. There are dynamic bearings to generate. In the latter bearing, the distance between the two members cannot be increased in order to form a “narrow” space into which the fluid is forced. Further, in both the former and the latter bearings, the distance between the two members cannot be increased in order to prevent the fluid pressure from escaping. Therefore, when the interval between the two members fluctuates, it is not possible to set the interval large in advance in consideration of the variation.

  In the following Patent Document 1, a configuration is shown in which one member of the thrust bearing is elastically supported to cope with a change in the interval between the members. That is, in a thrust bearing that dynamically generates fluid pressure between a thrust disk that rotates with the shaft and a fluid foil member that is fixed in the rotational direction, the back surface of the fluid foil member is supported by a plurality of spring foil members. However, a configuration is shown in which the spring foil member is elastically deformed to allow displacement of the fluid foil member. According to this configuration, since the other member can be displaced following the displacement of one of the two members that move relative to each other, the distance between the two members can be set narrow in advance. .

Japanese Patent Laid-Open No. 10-61660

  In the bearing described in the above-mentioned Patent Document 1, a fluid foil member, that is, a member that is in contact with a fluid generating pressure and is elastically supported from the back surface is formed of a thin plate and has low rigidity. For this reason, when the pressure of the fluid becomes high, the member is deformed by the pressure, and the desired shape determined to generate the pressure of the fluid cannot be accurately maintained. Therefore, since the bearing including this member reduces the allowable load expected when the shape does not deform, a relatively large allowable load cannot be achieved, and if a large allowable load is to be obtained, a large bearing area is required. There was a problem that it was necessary and there was a restriction on high-speed rotation, and it was not practical.

  In addition, as is generally true for fluid dynamic bearings using dynamic pressure, there are demands such as supplying a sufficient amount of fluid for generating dynamic pressure and generating large dynamic pressure.

  Provided is an advantageous configuration for suppressing deformation of a member in contact with fluid of a fluid dynamic bearing due to fluid pressure. A configuration suitable for increasing the pressure of the fluid in the bearing is provided.

  Further, the present invention provides a bearing structure that is advantageous in efficiently supplying fluid to the bearing portion and efficiently generating dynamic pressure.

  The fluid dynamic bearing of the present invention elastically supports one of the two members facing each other through the fluid, thereby absorbing the change in the interval between the two members and suppressing the variation in the interval. Moreover, the rigidity of the member that is elastically supported and is in contact with the fluid is sufficiently increased, and deformation due to the pressure of the fluid is suppressed. That is, the member in contact with the fluid is sufficiently larger than the rigidity of the elastic member that supports the member, whereby the displacement of the other member is absorbed by the deformation of the elastic member while generating the pressure of the member. The shape for this is maintained by the high rigidity of the member.

  When the fluid dynamic bearing of the present invention is applied as a thrust bearing, the two members facing each other through the fluid have a substantially annular plate shape, extend radially to one of the opposing surfaces of these members, and the inner end thereof is It is possible to provide a radiating groove that opens inward in the radial direction and a concave portion in which one end in the circumferential direction is continuous with the radiating groove and the other end is isolated. The fluid is supplied from the inner periphery to the recess through the radiation groove. The fluid can be efficiently sent from the radiation groove to the recess so that the outer circumferential end of the radiation groove is located inside the annular outer circumference of the member provided with the radiation groove. By allowing the radial groove to reach the outer periphery and making the opening cross-sectional area of the outer end smaller than the opening cross-sectional area of the inner end, the fluid can be efficiently sent to the recess. . In addition, when the radiation groove has a substantially constant cross-sectional area and reaches the outer peripheral edge, at least a part of the outer opening of the radiation groove is provided by an outer ring arranged so as to surround the member provided with the radiation groove. As a result, a part of the fluid flow can be damped to facilitate the flow into the recess.

  As for the concave portion, the outer side is located inside the outer periphery of the ring of the member provided with the concave portion, and pressure can be efficiently generated so that the fluid does not escape to the outside. Further, when the outer side reaches the outer periphery of the ring, the fluid can be prevented from escaping by the outer ring arranged so as to surround the member provided with the recess. It is also preferable that the depth of the concave portion is deep on the inner peripheral side and shallow on the outer peripheral side. In particular, the bottom of the recess can be formed in a two-step shape, the inner peripheral step can be deep, and the outer peripheral step can be shallow. In the shallow part, the pressure is effectively increased when the rotational speed of the shaft is low, and in the deep part, a large pressure is generated when the rotational speed is high. Thus, by making the depth of the recesses different in the radial direction, a large dynamic pressure effect can be effectively obtained in a wider rotational speed range.

  The fluid filled between the two members is dragged by the rotating member to generate a flow in the circumferential direction. At that time, a speed gradient is generated in the gap between the members, and the rotating member side becomes higher. Since the pressure of the fluid is proportional to the speed, higher pressure is generated when the radial groove and the recess are formed on the rotating member side. On the other hand, centrifugal force is generated by the rotation, and the fluid in the gap tends to flow outward in the radial direction. Since pressure is generated by a circumferential flow from the radiation groove to the recess, higher pressure is generated if the pressure in the radiation groove increases. Therefore, the outer peripheral end of the radiating groove is not opened, or a part of the radiating groove is closed to reduce the open sectional area so that the pressure in the radiating groove is increased by centrifugal force in the radiating groove.

  The fluid dynamic bearing of the present invention can be applied as a radial bearing. A fluid bearing is constituted by the surface of the shaft and a substantially cylindrical member facing the fluid through the fluid. An axial groove extending in the axial direction is formed on one of the opposed surfaces, and one end in the circumferential direction is formed into the axial groove. A recess can be provided which is continuous and the other end is isolated from the axial groove. Fluid is efficiently supplied from the axial groove to the recess.

  When the thrust bearing is constituted by the fluid bearing of the present invention, the support point for elastically supporting one member is preferably near the radially inner end of the surface of the member that receives the fluid pressure. Since the displacement of the member fixed to the shaft is large on the outside in the radial direction and small on the inside, the support on the inside can cope with the displacement better.

  When the thrust bearing is constituted by the fluid bearing of the present invention, it is preferable that the two members are parallel or that the gap between the two members is made smaller on the outer side in the radial direction. The pressure of the fluid generated between the two members increases on the radially outer side. Correspondingly, the member is displaced and the radial gap is increased. On the other hand, if the gap in the radial direction is reduced in advance, the gap can be kept parallel even if displacement due to pressure occurs.

  The fluid bearing of the present invention can increase the allowable load by supplying the compressed fluid from the inner peripheral sides of the two members. The pressure in the gap between the members increases due to the static pressure effect caused by supplying the compressed fluid, and the dynamic pressure effect due to the relative movement between the members can also be enhanced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of a turbocharger 10 to which a fluid dynamic bearing according to an embodiment of the present invention is applied. The left side of the drawing constitutes the compressor 12 and the right side constitutes the turbine 14. A compressor impeller 18 is fixed to the left end of the shaft 16 common to the compressor 12 and the turbine, and a turbine rotor 20 is fixed to the right end, and the three rotate together. A radial bearing 22 is formed on the shaft 16 between the compressor 12 and the turbine 14. A thrust bearing 24 is formed on the back side of the compressor 12. As shown in the figure, the radial bearing 22 may be arranged with a long shaft length in addition to two bearings with a relatively short shaft length.

  The thrust bearing 24 is composed of a rotating disk 26 that is coaxially fixed to the shaft 16 and rotates integrally therewith, and bearings 30 and 32 that are supported by the casing 28 while being restricted in movement in the rotational direction. The two bearing portions 30 and 32 are arranged so as to sandwich the rotating disk 26, and restrict the axial movement of the rotating disk 26, that is, the shaft 16, the impeller 18, and the rotor 20. A bearing portion 30 (hereinafter referred to as a front bearing portion 30) on the front surface side (left side in the drawing) of the rotating disk 26 is opposed to the rotating disk 26, being elastically supported by a bearing base 34 fixed to the casing and a spring. A front facing disk 36 is included. Details of the support structure by the spring will be described later. On the other hand, the bearing portion 32 (hereinafter referred to as the rear bearing portion 32) on the rear surface side (right side in the drawing) of the rotating disk 26 includes a rear surface facing disk 38 fixed to the casing 28. Like the front counter disk 36, the rear counter disk 38 is opposed to the rotary disk 26, but is not elastically supported like the front counter disk 36, and is in a rotational direction with respect to the casing 28. It is fixed so that it does not move both axially and axially.

  The mutually facing surfaces of the rotating disk 26 and the front and rear facing disks 36, 38 are shaped to generate pressure on the fluid in the region sandwiched between the facing surfaces. The movement of the rotating disk 26 and the like in the axial direction is restricted, and positioning is achieved. This shape will be described in detail later.

  FIG. 2 is an exploded perspective view showing the front and rear bearing portions 30 and 32 and the rotating disk 26 constituting the thrust bearing. FIG. 3 is a diagram showing details of the support structure for the front facing disk 36. The front facing disk 36 is supported by a bearing base 34 fixed to the casing 28 via a ring-shaped spring 40. More specifically, the spring 40 is fixed to the bearing base 34 with a screw 44 via an inner ring 42 in the vicinity of the inner periphery thereof, and on the other hand, with respect to the front facing disk 36 in the vicinity of the outer periphery. It is fixed with a screw 48 through an outer ring 46. With this structure, the front facing disk 36 is restricted from moving in the rotational direction, while the axial movement or the inclination of the shaft is allowed by the elasticity of the spring 40.

  When the turbocharger 10 is operated, the shaft 16 receives thrust toward the compressor 12 side, that is, leftward. For this reason, the rotating disk 26 basically approaches the front counter disk 36 side, and this gap is narrower than the rear counter board 38 side. That is, the fluctuation of the rotating disk 26 and the gap due to the swinging of the shaft 16 has a larger influence on the front side, and in the apparatus of this embodiment, the elastic support structure is provided in the bearing portion 30 on the front side. Therefore, in other devices, if the influence on the rear side is significant, an elastic support structure can be provided here, and the affected side changes depending on the operating state, etc. It is also possible to provide both.

  As shown in FIG. 2, recesses or grooves are formed on the surfaces of the front and rear facing discs 36 and 38 that face the rotating disc 26. That is, it has a radial groove 50 extending in the radial direction from the inner circumference to a little before the outer circumference, and a pocket groove 52 as a recess provided in a substantially arc shape or a substantially arc shape near the middle of the inner circumference and the outer circumference. 4 and 5 show details of these grooves. FIG. 5 is a cross-sectional view taken along the line XX shown in FIG. 4, that is, a circular arc concentric with the rear facing disk 36. The radial groove 50 has an inner peripheral end that reaches the inner peripheral edge of the front facing disk 36 but does not reach the outer peripheral edge. Thereby, it is suppressed that the fluid in the radiation groove 50 escapes to the outer peripheral side by the centrifugal force by rotation. The pocket groove 52 extends downstream of the radiating groove 50 with respect to the fluid flow, and a wall surface 54 is formed on the outer peripheral side, the inner peripheral side, and the downstream side around the groove.

  The rotating disk 26 rotates counterclockwise as indicated by an arrow A in FIG. 4A, and this rotation causes the fluid interposed between the rotating disk 26 and the front facing disk 36 to be dragged. Rotate in the direction. This fluid flow is indicated by arrow B in FIG. Further, the fluid supplied to the pocket groove 52 by the radiating groove 50 from the inside of the front facing disk 36 also flows in the direction of the arrow C by the flow in the circumferential direction. As shown in FIG. 5, the bottom surface of the pocket groove 52 is inclined so as to gradually become shallower along the fluid flow, and reaches the wall surface 54. The fluid flows so as to be pushed into the wedge-shaped and stepped space, and is narrowed, whereby the pressure P is generated. This pressure P becomes a force for supporting the rotating disk 36, that is, the shaft 16 in the axial direction. At this time, wall surfaces 54 are respectively provided on the inner peripheral side and the outer peripheral side of the pocket groove 52, thereby suppressing the pressure generated by the fluid flow from escaping to the side of the flow.

  Radial grooves and pocket grooves similar to those of the front counter disk 36 are also formed in the rear counter disk 38. The rotating disk 26 is sandwiched between the two opposing disks 36 and 38 in the axial direction, and the shaft 16 is axially moved by the pressure generated by the groove shape formed on the surfaces constituting the bearings of these disks. Supported.

  In the present embodiment, the pocket groove 52 is configured to gradually become shallower along the fluid flow, but may be formed to the same depth.

  According to the present embodiment, a pocket provided so as to be recessed from the surroundings on one of the mutually facing surfaces of the shaft or the rotating member and the bearing portion, and the same surface as the surface provided with this pocket And a groove provided from the edge of the surface to the upstream edge of the pocket groove with respect to the fluid flow.

  The front-facing disc 36 that is elastically supported has sufficiently greater rigidity than the spring 40, and the deformation caused by the pressure generated in the fluid is sufficiently greater than that of the front-facing disc 36. . That is, the front facing disc 36 has sufficient rigidity to be regarded as a rigid body with respect to the spring 40. Since the front facing disk 36 is substantially rigid, the shape of the surface thereof including the radiation groove 50 and the pocket groove 52 is hardly deformed by the pressure of the fluid, and the pressure is stably generated and the thrust force is increased. Can be supported.

  In this embodiment, grooves that generate pressure are formed on the fixed surfaces among the surfaces constituting the bearing, that is, on the surfaces facing the rotating disks 26 of the front and rear facing disks 36 and 38. Grooves can also be formed on the rotating surface, that is, the surface of the rotating disk 26. In that case, an annular groove 53 is added to the inner peripheral portion as shown in FIG. As a result, the inner end of the radiating groove is opened toward the inner periphery, and the fluid helps to smoothly flow into the radiating groove 50 from the inner peripheral side.

  Also, the shape of the groove is such that the cross-sectional area of the flow becomes smaller in the direction of flow, and any shape can be used as long as the fluid is pushed into it and pressure is generated. Also good.

  FIG. 6 is a view showing another example of the support structure of the opposing disk, and is drawn corresponding to FIG. A counter disk 56 corresponding to the front counter disk 36 of FIG. The counter disk 56 is elastically supported by a back support plate 60 fixed to a bearing base 58 corresponding to the bearing base 34 shown in FIG. The back support disc 60 is fixed to the bearing base 58 with screws 62, and is integrated with both the rotation direction and the axial direction. The opposing disk 56 and the back support disk 60 are annular disks having the same outer diameter, and outer peripheral grooves 64 and 66 extending in the circumferential direction are formed on the outer peripheral surface thereof. An annular clip 68 having a U-shaped cross section is engaged so as to bridge the two outer peripheral grooves 64 and 66. Further, between the counter disk 56 and the back support disk 60, a spring 70 having a generally S-shaped cross section as shown in the figure and disposed as a whole is disposed. In a state where the spring 70 is compressed, the outer peripheries of the opposing disk 56 and the back support disk 60 are stopped by the aforementioned clip 68, and these disks are coupled. As shown in the figure, a gap is formed between these discs 56 and 60, and the opposing disc 56 is allowed to move in the axial direction including tilting of the shaft. The counter disk 56 is provided with the radiation grooves and pocket grooves similar to the front counter disk 36 described above. It is also possible to provide these grooves on the rotating disk 26 side.

  7 to 10 show other examples of the surface shape of the counter disk. The counter disk 236 has a configuration similar to that of the counter disk 36 described above. That is, it has a radiation groove 250 and a pocket groove 252 provided in a recessed manner on the surface. The radiating groove 250 reaches the inner edge of the opposing disk 236, and is open toward the inner peripheral side here. On the other hand, the outer peripheral side end of the radiating groove 250 reaches the outer edge of the counter disk 236, but as shown in FIG. 8 and FIG. Is smaller than the inner circumference. That is, the radial groove 250 is a deep groove portion 250a deeply carved on the inner peripheral side, and a shallow groove portion 250b carved shallowly on the outer peripheral side. The shallow groove portion 250b is provided in the vicinity of the outer peripheral edge of the counter disk 236, and generates a pressure by blocking the fluid flowing through the radiation groove 250 to some extent. Further, in order to reduce the cross-sectional area of the groove on the outer peripheral side of the radiating groove 250, a method other than the method of changing the depth shown in FIG. 9 can be employed. For example, the width of the groove can be reduced.

  FIG. 10 shows a cross section of the pocket groove 252 taken along the line Y1-Y1 shown in FIG. As shown in the figure, the pocket groove 252 also has different depths on the inner peripheral side and the outer peripheral side. That is, it has a staircase shape with two steps in the radial direction, having a deep groove portion 252a on the inner peripheral side and a shallow groove portion 252b on the outer peripheral side. The dynamic pressure due to the flow in the circumferential direction is first generated in a shallow portion when the rotational speed is increased, and is generated in a deep portion after becoming high speed. In the high speed region, it is a deep part that generates a large pressure. In the present embodiment, the outer peripheral side is the shallow groove portion 252b, and the pressure is increased on the outer side in the radial direction, and the force for suppressing the vibration of the rotating disk is generated on the outer side. Thereby, the shake at the time of low rotation is efficiently suppressed. Further, the deep groove portion 252a is provided on the inner side so that a large force is generated on the inner side during high rotation, thereby reducing the bending moment applied to the rotating disk 26 and the counter disk 236, and suppressing the deformation of these disks. ing.

  11 and 12 show still another example of the surface shape of the counter disk. The counter disk 336 also has a configuration similar to that of the counter disk 36 described above, and includes a radiation groove 250 and a pocket groove 352 as a recess. The radiation groove 250 is exactly the same as that shown in FIG. The outer end of the pocket groove 352 reaches the outer peripheral edge of the counter disk 336. Further, as shown in the cross-sectional view along line Y2-Y2 of FIG. 12, it has a two-step staircase configuration similar to the pocket groove 252 described above. The outer shallow groove portion 352b functions to prevent the fluid from flowing outward with respect to the inner deep groove portion 352a, thereby ensuring the generation of dynamic pressure in the deep groove portion 352a. Fluid that escapes from the shallow groove portion 352b to the outer periphery can be prevented by disposing a ring outside the counter disk 352 with a slight gap on the outer periphery thereof.

  The surface shape of the opposing disk shown in FIGS. 7 and 11 can also be applied to a rotating disk. In this case, as shown in FIG. 4B, it is preferable to provide an annular groove so that the fluid can easily flow into the radiation groove.

FIG. 13 is a view showing an example of the arrangement of the counter disk 436 and the bearing base 434. Basically, the arrangement shown in FIG. 3 is followed, but the relationship between the radial groove 450 of the opposing disk 436, the outer periphery of the opposing disk 436, and the bearing base 434 is different from the above example. The radiation groove 450 reaches the outer peripheral edge of the counter disk 436. Further, a ring-shaped portion (hereinafter, referred to as a ring portion 434 a) of the bearing base 434 facing the outer periphery of the counter disk 436 is located with a slight gap from the counter disk 436. Steps are formed with respect to the opening on the outer side of the radiating groove 450 so as to form a narrow gap (left side in the figure) and a wide gap (right side). By controlling the cross-sectional area of the opening portion of the radiating groove 450, the flow of fluid in the radiating groove is controlled. Thereby, the process of the outer edge part of a radiation groove becomes easy. Further, since the ring portion 434a is close to the counter disk 436, for example, even when the pocket groove reaches the outer peripheral edge of the counter disk as shown in FIG. Can be prevented from escaping to the outer peripheral side. Further, the present invention can be applied even when a radial groove is provided in the rotating disk.

  FIG. 14 shows still another example of the surface shape of the counter disk 536. The radiation groove 550 and the pocket groove 552 are curved. In this example, the fluid turns clockwise in the figure contrary to the above-described example. Radiation grooves and pocket grooves are curved at the outer part, forming a flow inward due to the velocity component in the circumferential direction of the fluid, suppressing the flow outward in the radial direction, and efficiently generating dynamic pressure This is to make it happen.

  Next, the configuration of the radial bearing 22 (see FIG. 1) will be described. 15 to 17 are diagrams showing the configuration of the radial bearing 22. 15 is a cross section including the shaft, FIG. 16 is a cross-sectional view perpendicular to the axis, and FIG. 17 is a view showing a state where the bearing surface is developed. A sleeve 72 having a cylindrical outer peripheral surface is fixed to the shaft 16 coaxially therewith, and rotates integrally with the shaft 16. An outer peripheral bearing portion 74 is provided in the casing 28 so as to surround the sleeve 72. The outer peripheral bearing portion 74 includes a counter cylinder 76 having a bearing surface facing the outer peripheral surface of the sleeve 72, and a bearing base 78 fixedly coupled to the casing 28, and further elastically supports the counter cylinder 76 with respect to the bearing base 78. A spring 80 is provided. The spring 80 is disposed between the inner peripheral surface of the bearing base 78 and the outer peripheral surface of the opposed cylinder 76, and has a shape in which a thin plate of spring steel is formed in an annular shape and provided with irregularities at predetermined intervals in the circumferential direction. It has become. By elastically supporting the opposed cylinder 76 by the spring 80, it is possible to absorb a fall of the shaft 16 such as movement in the radial direction and swinging.

  The inner peripheral surface 82 of the opposed cylinder 76 has a shape that generates pressure on the fluid in the gap between the opposed cylinder 76 and the sleeve 72. Specifically, an axial groove 84 extending in the axial direction and a substantially square pocket groove 86 are formed. These grooves correspond to the radial groove 50 and the pocket groove 52 in the thrust bearing 24 described above, the axial groove 84 supplies fluid, and pressure is generated by the fluid fed into the pocket groove 86 by the rotation of the sleeve 72. . Further, the opposed cylinder 76 has sufficient rigidity with respect to the spring 80 as in the above-described opposed disk 36, and the deformation due to the pressure generated in the fluid is slight, and the displacement due to the non-uniform pressure is The spring 80 is carried by elastic deformation.

  In the radial bearing 22 and the thrust bearing 24 of the present embodiment, the fluid responsible for pressure generation is gas, particularly air. The air compressed by the compressor 12 is guided from the vicinity of the outlet of the compressor impeller 18 through the passage 88 and the gap between the rear casing 90 and the bearing base 34 to the inner peripheral side of the front bearing 30. From here, it enters the radiation groove 50 and is supplied between the rotating disk 26 and the front facing disk 36. Air is supplied to the rear bearing portion 32 and the radial bearing 22 through a passage 92 provided in the casing 28. In the rear bearing portion 32 as well, air is guided into the bearing by the radiation groove. In the radial bearing 22, air is introduced into the bearing by the axial groove 84.

  FIG. 18 is a diagram illustrating another configuration example of the thrust bearing. Opposing to the rotating disk 100, an opposing disk 102 that is elastically supported is disposed. On one of the opposing surfaces of these discs, a groove similar to that of the aforementioned front facing disc 36 is formed. The rotating disk 100 and the counter disk 102 increase in thickness toward the outer periphery. Corresponding to the increased pressure on the outer peripheral side, the opposing disk 102 is deformed to be larger on the outer peripheral side and away from the rotating disk 100. In order to cancel this deformation, the thickness is changed in advance so as to reduce the interval on the outer peripheral side. In FIG. 10, the thickness of both the rotating disk 100 and the counter disk 102 is changed, but it is also possible to use only one of them.

  FIG. 19 is a diagram showing still another configuration example of the thrust bearing. A counter disk 106 that is elastically supported is disposed opposite the rotating disk 104. On one of the opposing surfaces of these discs, a groove similar to that of the aforementioned front facing disc 36 is formed. The counter disk 106 is supported by the support portion 108 on the innermost peripheral side. The support portion 108 has elasticity, and when it is bent, the opposing disk 106 is displaced. Since this displacement is supported on the inner peripheral side, the displacement on the outer peripheral side becomes large. On the other hand, when the rotating disc 104 is tilted due to the swing of the shaft, the outer circumference of the axial displacement of each part of the rotating disc 104 becomes large. As described above, since the opposing disk 106 becomes larger on the outer periphery, the counter disk 106 is displaced more effectively in response to the falling of the rotating disk 104 and contact with the rotating disk 104 is prevented.

  FIG. 20 is a diagram showing still another configuration example of the thrust bearing. A counter disk 114 that is elastically supported by a support member 112 is disposed opposite to the rotating disk 110. The support member 112 is substantially L-shaped, and its short side is fixed to the housing, and the long side is fixed near the inner periphery of the counter disk 114. Also in this configuration, as in FIG. 11, the outer peripheral side of the counter disk 114 becomes a free end, and a larger displacement is allowed, and the swinging of the rotating disk 110 can be absorbed.

  FIG. 21 is another example of a device employing the fluid dynamic bearing according to the present invention. FIG. 21 shows an apparatus in which a generator 128 is attached to a shaft 126 that fixes a compressor 120 and a turbine 122 of a micro gas turbine. A radial bearing 130 is disposed in front of and behind the generator 128, and a thrust bearing 132 is disposed in front of the generator 128, that is, on the compressor 120 side. The configurations of the radial bearing 130 and the thrust bearing 132 are the same as those of the radial bearing 22 and the thrust bearing 24, respectively, and description thereof is omitted.

  FIG. 22 shows still another example of the apparatus employing the fluid dynamic bearing according to the present invention. FIG. 22 shows an apparatus including an electric motor 140 and a compressor 142 driven by the electric motor 140. Radial bearings 144 that support the shaft are disposed before and after the electric motor 140. In addition, a thrust bearing 146 is disposed on the back surface of the impeller of the compressor 142, and a radial bearing 148 is disposed further rearward. The configurations of the individual radial bearings 144 and 148 and the thrust bearing 146 are the same as those of the radial bearing 22 and the thrust bearing 24, respectively, and a description thereof is omitted.

  FIG. 23 shows a turbine generator which is still another example of an apparatus employing the fluid dynamic bearing according to the present invention. The turbine generator is a device including a generator 150 and a turbine 152 that drives the generator 150. Radial bearings 154 that support the shaft are arranged before and after the generator. In addition, a thrust bearing 156 is disposed on the rotor rear surface of the turbine. The configurations of the individual radial bearings and thrust bearings are the same as those of the aforementioned radial bearing and thrust bearing.

1 is a diagram showing a schematic configuration of a turbocharger to which an embodiment of a hydrodynamic bearing of the present invention is applied. It is a disassembled perspective view of the thrust bearing of this embodiment. It is sectional drawing which shows the detail of the support structure of the front opposing disk 36. FIG. It is a figure which shows the shape of the surface (bearing surface) of the front facing disc 36, or the surface of a rotating disc. 4 is a cross-sectional view of a front facing disc 36. FIG. It is sectional drawing which shows the support structure of the other front opposing board 56. FIG. Furthermore, it is a figure which shows the shape of the surface (bearing surface) of the other front opposing disk 236. FIG. FIG. 8 is a partial detail view of FIG. 7. It is the ZZ sectional view taken on the line of FIG. It is the Y1-Y1 sectional view taken on the line of FIG. Furthermore, it is a figure which shows the shape of the surface (bearing surface) of the other front opposing disk 336. FIG. FIG. 12 is a sectional view taken along line 2-Y2 of FIG. 11. It is a figure which shows the positional relationship of the opposing disc 436 and the bearing base 434. FIG. Furthermore, it is a figure which shows the shape of the surface (bearing surface) of the other front opposing disk 536. FIG. It is sectional drawing containing the axis | shaft of the radial bearing of this embodiment. FIG. 16 is a cross-sectional view perpendicular to the axis of the radial bearing of FIG. 15. It is a figure which shows the state which expand | deployed the internal peripheral surface of the opposing cylinder 76 of the radial bearing of FIG. It is a figure which shows the other structure regarding the support structure of a thrust bearing. It is a figure which shows the further another structure regarding the support structure of a thrust bearing. It is a figure which shows the further another structure regarding the support structure of a thrust bearing. It is a figure which shows the other example of the apparatus with which the fluid bearing of this invention was applied. It is a figure which shows the further another example of the apparatus with which the fluid bearing of this invention was applied. It is a figure which shows the further another example of the apparatus with which the fluid bearing of this invention was applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Turbocharger, 12 Compressor, 14 Turbine, 16 Shaft, 22 Radial bearing, 24 Thrust bearing, 26 Rotating disk, 28 Casing, 30 Front bearing part, 32 Rear bearing part, 34 Bearing base part, 36 Front facing disk, 38 Rear facing disk, 40 spring, 50 radial groove, 52 pocket groove, 72 sleeve, 74 outer peripheral bearing part, 76 opposed cylinder, 78 bearing base, 80 spring, 84 axial groove, 86 pocket groove.

Claims (26)

A shaft or a rotating member that rotates integrally with the shaft, and a bearing portion that is disposed to face the shaft or the rotating member, and the shaft or the rotating member and the bearing portion move relative to each other. A hydrodynamic bearing that supports a shaft via a compressible fluid interposed therebetween,
The bearing portion is
A base member;
A facing member having a bearing surface facing the rotating member;
An elastic member that elastically supports the opposing member with respect to the base member;
Have
The opposing member is a rigid body, and is elastically supported by the elastic member, so that it can follow the displacement of the shaft or the rotating member.
Fluid bearing. The hydrodynamic bearing according to claim 1,
Each of the rotating member and the opposing member has a substantially annular plate shape coaxial with the shaft, and extends radially on one of the opposing surfaces of these members, and its inner end faces radially inward. And a radiating groove that is open, and one end in the circumferential direction is continuous with the radiating groove, and has a recess that is isolated at the other end.
Fluid bearing.   3. The hydrodynamic bearing according to claim 2, wherein an outer end of the radiation groove is located inside an outer peripheral edge of the rotating member or the opposing member provided with the radial groove.   The hydrodynamic bearing according to claim 2, wherein an outer end of the radiation groove is open to an outer peripheral edge of the rotating member or the opposing member provided with the radial groove.   5. The hydrodynamic bearing according to claim 4, wherein an open section cross-sectional area of the outer end of the radiation groove is smaller than an open section cross-sectional area of the inner end. The hydrodynamic bearing according to claim 4,
An outer peripheral ring disposed around an outer periphery of the rotating member or the opposing member provided with the radiation groove;
The outer peripheral ring covers a part of the open portion at the outer end of the radiation groove, and reduces the cross-sectional area of the open portion.
Fluid bearing.   It is a fluid bearing of Claim 2, Comprising: The fluid bearing in which the outer end of the said recessed part is located inside the outer periphery of the said rotation member or the said opposing member in which this was provided.   It is a fluid bearing of Claim 2, Comprising: The fluid bearing in which the outer end of the said recessed part has reached the outer periphery of the said rotating member or the said opposing member in which this was provided.   The fluid dynamic bearing according to claim 7 or 8, wherein the depth of the concave portion is deep on the inner peripheral side and shallow on the outer peripheral side.   The hydrodynamic bearing according to claim 9, wherein the bottom surface of the concave portion has a stepped shape in two steps in the radial direction. The hydrodynamic bearing according to claim 2,
The radiation groove and the recess are provided in the rotating member,
The rotating member further has an annular groove disposed on the inner side of the concave portion and separated from the concave portion,
The inner end of the radial groove reaches the annular groove,
Fluid bearing. The hydrodynamic bearing according to claim 1,
The opposing member has a substantially cylindrical shape coaxial with the shaft, and extends in one of the opposing surfaces of the opposing member and the rotating member in the axial direction, with at least one end reaching the end of the fluid bearing. The axial groove and one end in the circumferential direction are continuous with the axial groove, the other end is isolated, and both ends in the axial direction are located inside the both ends of the fluid bearing,
Fluid bearing. The hydrodynamic bearing according to claim 1,
The rotating member has a substantially annular plate shape having a rotation axis coaxial with the axis;
The opposing member is a plate-like member disposed so as to be substantially parallel to the rotating member.
Fluid bearing. The hydrodynamic bearing according to claim 1,
The rotating member has a substantially annular plate shape having a rotating shaft coaxial with the shaft,
The counter member is a fluid bearing constituted by a plate-like member arranged so as to be substantially parallel to the rotating member or so that a gap between the opposing members becomes smaller outside in the radial direction. A shaft or a rotating member that rotates integrally with the shaft, and a bearing portion that is disposed to face the shaft or the rotating member, and the shaft or the rotating member and the bearing portion move relative to each other. A hydrodynamic bearing that supports a shaft via a compressible fluid interposed therebetween,
The rotating member has a substantially annular plate shape coaxial with the shaft, and a radial groove extending in a radial direction and one end in a circumferential direction are continuous with the radial groove on a surface facing the bearing portion of the rotating member. The other end is isolated, and an annular ring groove disposed apart from the recess is provided inside the recess,
The inner end of the radial groove reaches the annular groove,
Fluid bearing. A shaft or a rotating member that rotates integrally with the shaft, and a bearing portion that is disposed to face the shaft or the rotating member, and the shaft or the rotating member and the bearing portion move relative to each other. A hydrodynamic bearing that supports a shaft via a compressible fluid interposed therebetween,
The bearing portion has a bearing surface facing the rotating member, and has a facing member having a substantially annular shape coaxial with the shaft,
The bearing surface has a radial groove extending in a radial direction and having an inner end reaching an annular inner peripheral edge of the bearing portion, one end in the circumferential direction is continuous with the radial groove, and the other end is Provided with an isolated recess,
Fluid bearing.   The hydrodynamic bearing according to claim 15 or 16, wherein an outer end of the radiation groove is located inside an outer peripheral edge of the rotating member or the opposing member provided with the radial groove.   The hydrodynamic bearing according to claim 15 or 16, wherein an outer end of the radiation groove is open to an outer peripheral edge of the rotating member or the opposing member provided with the radial groove.   The hydrodynamic bearing according to claim 18, wherein an open section cross-sectional area of the outer end of the radiation groove is smaller than an open section cross section of the inner end. The hydrodynamic bearing according to claim 18,
An outer peripheral ring disposed around an outer periphery of the rotating member or the opposing member provided with the radiation groove;
The outer peripheral ring covers a part of the open portion at the outer end of the radiation groove, and reduces the cross-sectional area of the open portion.
Fluid bearing.   The hydrodynamic bearing according to claim 15 or 16, wherein an outer end of the concave portion is located inside an outer peripheral edge of the rotating member or the opposing member provided with the concave portion.   The hydrodynamic bearing according to claim 15 or 16, wherein an outer end of the concave portion reaches an outer peripheral edge of the rotating member or the opposing member provided with the concave portion.   23. The fluid dynamic bearing according to claim 21, wherein the depth of the concave portion is deep on the inner peripheral side and shallow on the outer peripheral side.   24. The fluid dynamic bearing according to claim 23, wherein a bottom surface of the concave portion has a stepped shape having two steps in a radial direction. 25. The fluid dynamic bearing according to claim 1, wherein compressed fluid is supplied from an inner peripheral side of the bearing portion to a gap formed by the rotating member and the bearing portion. And flows through this gap toward the outer circumference,
Fluid bearing. A shaft or a rotating member that rotates integrally with the shaft, and a bearing portion that is disposed to face the shaft or the rotating member, and the shaft or the rotating member and the bearing portion move relative to each other. A fluid bearing that supports a shaft via a fluid interposed therebetween,
The compressed fluid is supplied from the inner peripheral side of the bearing portion to the gap formed by the rotating member and the bearing portion, and flows through the gap toward the outer peripheral side.
Fluid bearing.

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