Bearing

Abstract

Provided is a bearing capable of exhibiting sufficient dynamic pressure generation performance.　A dynamic pressure generation groove 10 communicating with at least one space S1 and generating dynamic pressure is provided on a sliding surface 5A of this bearing 5. The dynamic pressure generation groove 10 has a fluid introduction inclined surface 15 inclined in a depth direction from an introduction part 12 toward a dynamic pressure generation part 13, and a dynamic pressure generation surface 16 having an inclination angle smaller than that of the fluid introduction inclined surface 15. The sliding surface 5A is inclined to a mating sliding surface 3A side from a radial outer diameter side toward an inner diameter side.

Description

Bearing

[0001] The present invention relates to a bearing, for example, a bearing in which a base material and a rotating body are in direct contact and receive a thrust load.

[0002] A radial bearing or a thrust bearing that rotatably supports a rotating shaft constituting a rotating machine is used. For example, the bearing shown in Patent Document 1 is provided in a water pump. The water pump has a housing having a suction port and a discharge port, and an impeller disposed in the housing. The impeller pressurizes the pressurized fluid supplied from the suction port and sends it out to the discharge port by rotation.

[0003] The impeller is supported by a bearing attached to the inner peripheral surface with respect to the fixed shaft of the housing. The bearing has a function of a radial bearing on the inner peripheral surface and a function of a thrust bearing on the end face. The impeller moves to the suction port side due to the pressure difference between the pressurized high-pressure pressurized fluid and the low-pressure pressurized fluid before pressurization, but can support the load in the thrust direction by the thrust bearing function.

[0004] The end face of the bearing faces a thrust plate fixed to the housing side, and a lubricating groove extending in the radial direction is provided on the end face of the bearing. The fluid is discharged from the inner diameter side to the outer diameter side by the relative rotation with the thrust plate. This lubricating groove communicates with the inner diameter space and the outer diameter space, and the bottom surface is an inclined surface whose groove depth becomes deeper toward the relative rotation upstream side of the mating sliding surface from the land (hereinafter, simply referred to as the "relative rotation upstream side"). Dynamic pressure is generated at the end on the relative rotation downstream side of the mating sliding surface on the bottom surface (hereinafter, simply referred to as the "relative rotation downstream side") due to the relative rotation between the end face of the bearing and the thrust plate, and thereby the end face of the bearing can be floated from the thrust plate to reduce the frictional force between the end face of the bearing and the thrust plate.

[0005] Japanese Patent Application Laid-Open No. 2022-52709 (page 7, FIG. 3)

[0006] In bearings like the one described in Patent Document 1, fluid can be smoothly introduced to the downstream side of relative rotation along the slope of the bottom surface of the lubrication groove. However, since the bottom surface of the lubrication groove is composed of a single sloped surface, increasing the maximum depth of the lubrication groove increases the slope angle of the bottom surface, which may prevent the pressure from becoming sufficiently high at the downstream end of the bottom surface, potentially reducing the dynamic pressure generation capacity. Conversely, decreasing the maximum depth of the lubrication groove reduces the slope angle of the bottom surface of the lubrication groove, which may reduce the amount of fluid that can be introduced to the downstream end of the bottom surface of the lubrication groove, potentially reducing the dynamic pressure generation capacity.

[0007] This invention was made in view of these problems, and aims to provide a bearing that can reliably generate sufficient dynamic pressure.

[0008] To solve the aforementioned problems, the present invention provides a bearing that is disposed on at least one of a base material and a rotating body that rotate relative to each other and receives a thrust load, wherein the sliding surface of the bearing is provided with a dynamic pressure generating groove that communicates with at least one space and generates dynamic pressure, the dynamic pressure generating groove has a fluid introduction inclined surface that slopes in the depth direction from the introduction portion toward the dynamic pressure generating portion and a dynamic pressure generating surface with a smaller inclination angle than the fluid introduction inclined surface, and the sliding surface is inclined toward the mating sliding surface toward the inner diameter side in the radial direction. With this, during relative rotation, the fluid can be smoothly introduced from the introduction portion to the dynamic pressure generating portion while increasing the fluid pressure by the fluid introduction inclined surface, and the pressure can be further increased by the dynamic pressure generating surface with a smaller inclination angle to generate sufficient dynamic pressure. In addition, because the contact area between the sliding surface and the mating sliding surface is small due to the inclination, the friction torque in the initial stages of rotation can be reduced, and the fluid can be easily introduced between the sliding surfaces toward the other space from one space side to the other space side.

[0009] The fluid introduction inclined surface is composed of multiple inclined surfaces, and the inclination angle may be larger for inclined surfaces located at deeper positions. This allows for the smooth introduction of fluid from even deeper positions relative to the fluid introduction inclined surface.

[0010] The dynamic pressure generating surface may be an inclined surface that is inclined with respect to the sliding surface. This allows dynamic pressure to be effectively generated at the downstream end of the dynamic pressure generating surface on the relative rotation side.

[0011] The dynamic pressure generating groove may be in communication with the one space and the other space. This allows fluid to be introduced into the dynamic pressure generating groove from both radially adjacent spaces.

[0012] The dynamic pressure generating groove may have a symmetrical shape across a radially extending line. This allows dynamic pressure to be generated regardless of the rotation direction of the rotating body.

[0013] The inclination angle of the sliding surface may be between 0.1 degrees and 5 degrees, with the line extending perpendicular to the axis being zero degrees. This allows for a smaller contact area between the sliding surface and the mating sliding surface, as well as the stable generation of dynamic pressure.

[0014] This is a cross-sectional view showing a machine to which a bearing according to an embodiment of the present invention is attached. This is a view of the bearing from the axial direction. This is a cross-sectional view taken along line A-A in Figure 2. This is a cross-sectional view taken along line B-B in Figure 2. This is a schematic diagram showing the fluid flow in the dynamic pressure generating groove during relative rotation. This is a schematic diagram showing the state in which the sliding surfaces are lifted due to the dynamic pressure generated in the dynamic pressure generating groove during relative rotation. This is a schematic cross-sectional view showing the state between the bearing and the thrust plate during relative rotation. (a) is a schematic diagram showing modified examples of each inclined surface, and (b) is a schematic diagram showing yet another modified example of each inclined surface. This is a schematic diagram showing modified examples of the dynamic pressure generating groove. This is a schematic diagram showing yet another modified example of the dynamic pressure generating groove.

[0015] Embodiments for implementing the bearing according to the present invention will be described below based on examples.

[0016] The bearings according to the embodiment will be described with reference to Figures 1 to 7. In this embodiment, the bearings applied to the fluid pump 1 will be described. In Figure 1, the left and right sides of the paper represent the left and right sides of the fluid pump, and the top and bottom sides of the paper represent the top and bottom sides of the fluid pump.

[0017] The fluid pump 1 in this embodiment is a device that pressurizes a fluid to be pressurized, such as air, oil, or refrigerant, and sends it to downstream equipment, and is used in fields such as automobiles and general industrial machinery.

[0018] As shown in Figure 1, the bearing structure of the fluid pump 1 mainly consists of a fixed shaft 2, a thrust plate 3 as a base material, a rotating body 4, and a bearing 5. The fixed shaft 2 and thrust plate 3 can be said to constitute the fixed-side elements, while the rotating body 4 and bearing 5 constitute the rotating-side elements.

[0019] The fixed shaft 2 is fixedly positioned in a housing (not shown). The thrust plate 3 is a ceramic molded product, which is a low-friction member, and is annular in shape, fixed to the outer surface of the fixed shaft 2.

[0020] The rotating body 4 is cylindrical in shape, into which the fixed shaft 2 can be loosely inserted. The rotating body 4 is allowed to move slightly in the axial direction relative to the fixed shaft 2, and is also rotatable relative to the fixed shaft 2. This rotating body 4 is connected to a drive mechanism and an impeller (not shown).

[0021] The bearing 5 is fixed to the inner circumferential surface of the rotating body 4. The bearing 5 is a ceramic molded product, which is a low-friction material, and is substantially cylindrical in shape.

[0022] Furthermore, the thrust plate 3 and bearing 5 are not limited to being made of ceramics, but may also be made of SiC (hard material) or a combination of SiC (hard material) and carbon (soft material). In addition, any sliding material used for thrust bearings is applicable. As for SiC, there are sintered bodies using boron, aluminum, carbon, etc. as sintering aids, as well as materials consisting of two or more phases with different components and compositions, such as SiC with dispersed graphite particles, reaction-sintered SiC made of SiC and Si, SiC-TiC, SiC-TiN, etc. As for carbon, carbon mixed with carbonaceous and graphite materials, resin-molded carbon, sintered carbon, etc. can be used. In addition to the sliding materials mentioned above, metal materials, resin materials, surface modification materials (coating materials), composite materials, etc. can also be applied.

[0023] The bearing 5 has the function of a radial bearing that rotatably supports the rotating body 4 with respect to the fixed shaft 2, and also the function of a thrust bearing in which its end face 5A can slide against the end face 3A of the thrust plate 3. The end face 3A of the thrust plate 3 is a flat surface in which no dimples or the like are formed.

[0024] When the fluid pump 1 is operating, the internal space S1 (the space on the right side of the drawing) of the bearing 5 may be under higher pressure than the external space S2 (the space on the left side of the drawing). Due to this pressure difference, the bearing 5 and the rotating body 4 move to the left.

[0025] At this time, the thrust load acting from the bearing 5 and the rotating body 4 toward the thrust plate 3 is supported by the thrust plate 3 and the bearing 5, which are facing each other.

[0026] Next, the bearing 5 will be explained using Figures 2 to 4. Note that in Figure 4, for the sake of clarity, the inclination of the land 11 is shown as larger than it actually is.

[0027] As shown in Figure 2, multiple dynamic pressure generating grooves 10 are equally spaced in the circumferential direction on the end face 5A of the bearing 5, which serves as the sliding surface (three in this embodiment). The parts of the end face 5A other than the dynamic pressure generating grooves 10 form flat lands 11.

[0028] The dynamic pressure generating groove 10 includes an introduction section 12 and dynamic pressure generating sections 13 and 13' which serve as dynamic pressure generating sections.

[0029] An introduction section 12 is provided in the circumferential center of the dynamic pressure generating groove 10, a dynamic pressure generating section 13 is provided at the downstream end of the dynamic pressure generating groove 10 on the relative rotation side, and a dynamic pressure generating section 13' is provided at the upstream end of the dynamic pressure generating groove 10 on the relative rotation side.

[0030] These introduction sections 12 and dynamic pressure generating sections 13, 13' are in circumferential communication with each other and are also in communication with the inner space S1 and outer space S2 of the bearing 5, respectively.

[0031] The dynamic pressure generating groove 10 has a symmetrical shape with respect to a virtual line α that passes through the circumferential center and extends radially.

[0032] As shown in Figure 3, the dynamic pressure generating groove 10 is configured to gradually become shallower from the introduction section 12 towards the dynamic pressure generating sections 13 and 13', and has a roughly mortar-like shape in cross-section.

[0033] The introduction section 12 is the part of the dynamic pressure generating groove 10 that has the maximum depth H1. The dynamic pressure generating section 13 is the part that generates dynamic pressure using the fluid supplied from the introduction section 12 during forward rotation (solid line direction in Figure 2). The dynamic pressure generating section 13' is the part that generates dynamic pressure using the fluid supplied from the introduction section 12 during reverse rotation (dashed line direction in Figure 2).

[0034] The dynamic pressure generating groove 10 has three inclined surfaces 14, 15, and 16 that are inclined in the circumferential and depth directions of the end face 5A from the introduction section 12 toward the dynamic pressure generating section 13. These inclined surfaces 14, 15, and 16 each have different inclination angles. The dynamic pressure generating groove 10 also has three inclined surfaces 14', 15', and 16' that are inclined in the depth direction from the introduction section 12 toward the dynamic pressure generating section 13'. Since the inclined surfaces 14, 15, and 16 and the inclined surfaces 14', 15', and 16' are almost identical in configuration, only the inclined surfaces 14, 15, and 16 will be described, and the description of the inclined surfaces 14', 15', and 16' will be omitted.

[0035] The inclined surface 14, which serves as a fluid introduction inclined surface, is connected to the deepest position, i.e., the bottom surface 12a of the introduction section 12, and extends linearly, inclined toward the land 11 side toward the downstream side of relative rotation. The inclined surface 15, which serves as a fluid introduction inclined surface, is connected to the downstream side of the inclined surface 14, and extends linearly, inclined toward the land 11 side toward the downstream side of relative rotation. The inclined surface 16, which serves as a dynamic pressure generating surface, extends linearly, inclined such that the upstream side of relative rotation is connected to the inclined surface 15, and the downstream side of relative rotation is connected to the land 11.

[0036] The inclined surface 16 constitutes the bottom surface of the dynamic pressure generating section 13. The maximum depth H2 of the dynamic pressure generating section 13 is approximately 1 / 20th the maximum depth H1 of the introduction section 12.

[0037] The inclination angle θ1 of inclined surface 14 is greater than the inclination angle θ2 of inclined surface 15 (θ1 > θ2). Also, the inclination angle θ2 of inclined surface 15 is greater than the inclination angle θ3 of inclined surface 16 (θ2 > θ3). In other words, the inclination angles of inclined surfaces 14, 15, and 16 gradually increase with increasing depth (θ1 > θ2 > θ3).

[0038] As shown in Fig. 4, the land 11 has an inclined surface on the inner diameter side located on the end face 3A (see Fig. 1) side of the thrust plate 3, which is the mating sliding surface, closer to the outer diameter side.

[0039] Also, the inclination angle θ4 of the land 11 is approximately 3 degrees with the virtual line β perpendicular to the axis of the bearing 5 set as 0 degrees. That is, the inclination angle θ4 of the land 11 is included in the range of 0.1 degree or more and 5 degrees or less (0.1 ≤ θ4 ≤ 5). Here, the inclination angle of the sliding surface in this embodiment is the inclination angle θ4 of the land 11. That is, for the inclination angle of the sliding surface in this embodiment, it is sufficient that at least the inclination angle of the land on the sliding surface is included in the range of 0.1 degree or more and 5 degrees or less.

[0040] Next, the state of the bearing 5 when the rotating body 4 is non-rotating and rotating will be described. Here, the forward rotation of the rotating body 4 will be described.

[0041] As shown in Fig. 1, when the rotating body 4 is non-rotating, the end face 5A of the bearing 5 and the end face 3A of the thrust plate 3 are in contact in the axial direction.

[0042] As shown in Fig. 5, when the rotating body 4 is rotating forward, the fluid in the introduction part 12 in the dynamic pressure generating groove 10 follows and moves to the downstream side of relative rotation due to shear with the end face 3A of the thrust plate 3. Thereby, dynamic pressure is generated in the dynamic pressure generating part 13 of the dynamic pressure generating groove 10.

[0043] Specifically, the fluid near the bottom face 12a in the introduction part 12 is guided to the inclined surface 15 along the inclined surface 14, and the fluid near the inclined surface 15 is guided to the inclined surface 16 along the inclined surface 15. The fluid near the inclined surface 16 is guided to the downstream side of relative rotation along the inclined surface 16, and a large dynamic pressure is generated near the land 11. Since the dynamic pressure generating part 13 is formed shallowly, dynamic pressure is generated in the entire dynamic pressure generating part 13, but the largest dynamic pressure occurs near the downstream side of relative rotation of the dynamic pressure generating part 13, that is, near the land 11.

[0044] Also, when the rotating body 4 is rotating forward, the fluid in the inner space S1 is pressurized and the pressure becomes higher than that of the fluid in the outer space S2. Therefore, it is easier for the fluid to be introduced into the introduction part 12 from the inner space S1 and for the fluid to be discharged to the outer space S2.

[0045] Further, the fluid in the dynamic pressure generating portion 13' of the dynamic pressure generating groove 10 flows toward the introduction portion 12 due to shear with the end face 3A of the thrust plate 3.

[0046] As shown in FIG. 6, due to the dynamic pressure generated in the dynamic pressure generating portion 13, a force F in the direction in which the end face 5A of the bearing 5 and the end face 3A of the thrust plate 3 move away from each other in the axial direction is generated. As a result, the end face 5A of the bearing 5 and the end face 3A of the thrust plate 3 are slightly separated and do not contact each other, or the thrust force acting between the end face 5A of the bearing 5 and the end face 3A of the thrust plate 3 is reduced, so that the sliding property is improved.

[0047] Although not shown, when the rotating body 4 rotates in the reverse direction, the fluid in the dynamic pressure generating portion 13 moves to the introduction portion 12, the fluid in the introduction portion 12 moves to the dynamic pressure generating portion 13', and dynamic pressure is generated in the dynamic pressure generating portion 13'. Also in this case, the fluid flows smoothly along the inclined surfaces 14', 15', 16'.

[0048] Further, as shown in FIG. 7, the gap between the land 11 of the bearing 5 and the end face 3A of the thrust plate 3 tapers toward the inner diameter side. Therefore, the fluid flowing into the gap between the land 11 of the bearing 5 and the end face 3A of the thrust plate 3 enters up to the inner diameter side of the gap between the land 11 and the end face 3A of the thrust plate 3, and a so-called "wedge effect" in which the fluid is introduced to the inner diameter side of the gap between the land 11 and the end face 3A of the thrust plate 3 is likely to occur. Also, a high dynamic pressure is generated on the inner diameter side in the dynamic pressure generating portion 13.

[0049] As described above, during relative rotation, the fluid can be smoothly introduced from the introduction portion 12 to the dynamic pressure generating portion 13 while increasing the pressure of the fluid by the inclined surface 15 that becomes shallower toward the downstream side of the relative rotation. Further, in the dynamic pressure generating portion 13, the pressure can be further increased by the inclined surface 16 having a small inclination angle to generate sufficient dynamic pressure. In other words, since the fluid can be introduced from a deep position to the dynamic pressure generating portion 13 by the inclined surface 15, the dynamic pressure generating portion 13 can be made to have a depth that exhibits sufficient dynamic pressure generating ability.

[0050] Furthermore, inclined surfaces 14 and 15 are provided upstream of the inclined surface 16 in relative rotation, and the inclination angle of the inclined surfaces 14, 15, and 16 increases with depth. Therefore, fluid can be smoothly introduced into the dynamic pressure generating section 13 while gradually increasing the pressure from a deep position in the introduction section 12.

[0051] Furthermore, since the inclined surface 16 extends with a shallower slope toward the downstream side of relative rotation and is connected to the land 11, dynamic pressure can be effectively generated at the downstream end of the inclined surface 16 toward relative rotation.

[0052] Furthermore, since the dynamic pressure generating groove 10 is in communication with the inner space S1 and the outer space S2, fluid can be introduced into and out of the dynamic pressure generating groove 10 from the inner space S1 and the outer space S2. In this embodiment, the pressure in the inner space S1 is higher than that in the outer space S2, so fluid is easily introduced from the inner space S1 and easily led out into the outer space S2.

[0053] Furthermore, the dynamic pressure generating groove 10 has a symmetrical shape with respect to a virtual line α extending in the radial direction. This allows dynamic pressure to be generated in the dynamic pressure generating section 13 during forward rotation and in the dynamic pressure generating section 13' during reverse rotation.

[0054] Furthermore, the land 11 is inclined more towards the end face 3A of the thrust plate 3 on the inner space S1 side than on the outer space S2 side. As a result, the contact area between the land 11 and the end face 3A of the thrust plate 3 is small, which reduces the friction torque in the initial stages of rotation and makes it easier to introduce fluid between the land 11 and the end face 3A of the thrust plate 3 from the outer space S2 side to the inner space S1 side. In addition, a wedge effect is easily generated in the gap between the land 11 and the end face 3A of the thrust plate 3.

[0055] Furthermore, the end face 5A of the bearing 5 has a land inclination angle θ4 of approximately 3 degrees (0.1 ≤ θ4 ≤ 5), which is greater than zero degrees, thus reducing the contact area with the end face 3A of the thrust plate 3. Also, since the land inclination angle θ4 of the end face 5A of the bearing 5 is 0.1 degrees or more, a small contact area can be maintained even if initial wear occurs. In addition, since the land inclination angle θ4 of the end face 5A of the bearing 5 is 5 degrees or less, dynamic pressure can be stably generated in the dynamic pressure generating groove 10.

[0056] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0057] For example, in the above embodiment, the inclined surfaces 14, 15, and 16 were exemplified as flat surfaces with a straight cross-section. However, as shown in Figure 8(a), they may be composed of a single curved surface 215 that is convex in cross-section, provided that the inclination angle on the land side is smaller than that on the bottom side. Furthermore, the curved surface 215 may be a curved surface whose curvature changes continuously in the circumferential direction, provided that when the curved surface is divided into multiple sections in the circumferential direction, the curvature per unit length is smaller on the bottom side. Also, as shown in Figure 8(b), the inclined surfaces 314, 315, and 316 may be curved surfaces that are concave in cross-section. In addition, some of the multiple inclined surfaces may be curved in cross-section.

[0058] Furthermore, in the above embodiment, the dynamic pressure generating groove 10 is shown as having dynamic pressure generating sections 13, 13' formed on both sides of the introduction section 12 in the circumferential direction, thereby generating dynamic pressure in the dynamic pressure generating sections 13, 13' regardless of the direction of rotation. However, for example, as shown in Figure 9, if the dynamic pressure generating groove 510 is provided with inclined surfaces 514, 515, 516 extending from the introduction section 512 toward the dynamic pressure generating section 513 on the downstream side of relative rotation, the dynamic pressure generating section and inclined surfaces on the upstream side of relative rotation may be omitted.

[0059] Although the dynamic pressure generating groove 10 is exemplified as having a constant circumferential width and extending radially, it may also extend radially in a way that widens toward the outer diameter or inner diameter. Furthermore, the dynamic pressure generating groove 10 may extend radially, inclined toward one side in the circumferential direction from the inner diameter toward the outer diameter.

[0060] Furthermore, as shown in Figure 10, for example, the bearing 65 may be provided with side wall surfaces 617 and 617' on the upstream side of the relative rotation of the dynamic pressure generating groove 610, which guide fluid from the inner diameter and outer diameter to the radial center of the introduction portion 612. The side wall surface 617 extends linearly, inclined toward the downstream side of the relative rotation from the inner diameter to the outer diameter, and the side wall surface 617' extends linearly, inclined toward the downstream side of the relative rotation from the outer diameter to the inner diameter. This makes it easier to introduce fluid from the inner space S1 and outer space S2 along the side wall surfaces 617 and 617' during relative rotation. Note that the shape of the side wall surfaces 617 and 617' is not limited to a straight line, but may also be curved.

[0061] Furthermore, in the above embodiment, a configuration was illustrated in which three inclined surfaces 14, 15, and 16 are provided from the introduction section 12 toward the dynamic pressure generating section 13. However, as long as at least the inclined surfaces 15 and 16 close to the land 11 are provided, the configuration of inclined surface 14 may be omitted, or inclined surfaces may be provided that extend to deeper positions. Moreover, a vertical surface may be used instead of the inclined surface 14 located at a deeper position than the inclined surface 15.

[0062] Furthermore, in the above embodiment, the inclined surface 16 constituting the dynamic pressure generating section 13 was exemplified as being inclined and extending toward the downstream side of relative rotation, but it may also be a flat surface parallel to the land 11. In this case, the dynamic pressure generating section should be made to a depth that exhibits sufficient dynamic pressure generating capacity.

[0063] Furthermore, although the above embodiment illustrates a configuration in which the dynamic pressure generating groove 10 communicates with the inner space S1 and the outer space S2, it is sufficient if it communicates with at least one of them.

[0064] Furthermore, in the above embodiment, the dynamic pressure generating unit 13 was in communication with the inner space S1 and the outer space S2, but the area around the dynamic pressure generating unit may be separated from the inner space S1 and the outer space S2 by a land, as long as it is in communication with the introduction unit 12.

[0065] Furthermore, although the above embodiment illustrates a configuration in which the bearing is located on the rotating body side, it may also be located on the base material side.

[0066] Furthermore, the pressurized fluid may be a liquid or a gas, or it may be a mist-like mixture of liquid and gas.

[0067] Furthermore, although the above embodiment illustrates a configuration in which the base material is immobile, the base material and the rotating body may both rotate in the relative rotational direction.

[0068] Furthermore, although the above embodiment illustrates a configuration in which the bearing is applied to a fluid pump, it is not limited to this and may also be applied to compressors and the like.

[0069] Furthermore, although the above embodiment illustrates a configuration in which the bearing is separate from the base material or rotating body, the bearing may be provided integrally with the base material or rotating body, and the end face of the base material or the end face of the rotating body may be used as the sliding surface of the bearing.

[0070] 1 Fluid pump 2 Fixed shaft 3 Thrust plate (base material) 3A End face (mating sliding surface) 4 Rotating body 5 Bearing 5A End face (sliding surface) 10 Dynamic pressure generating groove 11 Land 12 Inlet section 13, 13' Dynamic pressure generating section 14, 15 Inclined surface (fluid inlet inclined surface) 16 Inclined surface (dynamic pressure generating surface) S1 Inner space (one space) S2 Outer space (other space) α Imaginary line β Imaginary line θ1 to θ3 Incline angle

Claims

1. A bearing disposed on at least one of a base material and a rotating body that rotate relative to each other, and which is subjected to a thrust load, wherein the sliding surface of the bearing is provided with a dynamic pressure generating groove that communicates with at least one space and generates dynamic pressure, the dynamic pressure generating groove having a fluid introduction inclined surface that slopes in the depth direction from the introduction portion toward the dynamic pressure generating portion and a dynamic pressure generating surface with a smaller inclination angle than the fluid introduction inclined surface, and the sliding surface of the bearing is inclined toward the mating sliding surface toward the inner diameter side in the radial direction.

2. The bearing according to claim 1, wherein the fluid introduction inclined surface is composed of a plurality of inclined surfaces, and the inclination angle is larger for inclined surfaces located at deeper positions.

3. The bearing according to claim 1, wherein the dynamic pressure generating surface is an inclined surface that is inclined with respect to the sliding surface.

4. The bearing according to claim 1, wherein the dynamic pressure generating groove is in communication with the one space and the other space.

5. The bearing according to claim 1, wherein the dynamic pressure generating groove has a symmetrical shape across a radially extending line.

6. The bearing according to claim 1, wherein the inclination angle of the sliding surface is 0.1 degrees or more and 5 degrees or less, with a line extending perpendicular to the axis being zero degrees.

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