Thrust bearing

Abstract

The invention provides a thrust bearing. The thrust bearing includes an upper foil portion including a bearing surface facing a rotating member rotatable about a rotational axis, and a lower foil portion elastically supporting the upper foil portion. The upper foil portion is divided into a plurality of portions.

Description

Technical Field

[0001] The present disclosure relates to a thrust bearing, and more particularly to the technical field of a foil laminated fluid thrust bearing. Background Art

[0002] For example, U.S. Patent No. 6,702,463 discloses a foil laminated fluid thrust bearing. U.S. Patent No. 9,062,712 is another related art document related to the present disclosure. Summary of the Invention

[0003] The thrust bearing is disposed between a rotating member and a stationary member. The thrust bearing includes a top foil portion having a bearing surface facing the rotating member. The thrust bearing bears a thrust in a direction in which the rotating shaft of the rotating member presses the bearing in a non-contact manner through a fluid film (e.g., air) between the rotating member and the top foil portion. When the relative speed between the thrust bearing and the rotating member is relatively high, the temperature of the fluid film rises due to viscous heating, and the load capacity of the thrust bearing may decrease. In the thrust bearing described in U.S. Patent No. 6,702,463, the top foil portion is formed of a single member. Therefore, in the thrust bearing described in U.S. Patent No. 6,702,463, the temperature of the fluid film may rise, and the load capacity of the thrust bearing may decrease.

[0004] The present disclosure provides a thrust bearing in which a decrease in the load capacity of the thrust bearing can be suppressed.

[0005] One aspect of the present disclosure relates to a thrust bearing. The thrust bearing includes an upper foil portion and a lower foil portion. The upper foil portion includes a bearing surface facing a rotating member that can rotate about a rotation axis. The lower foil portion elastically supports the upper foil portion. The upper foil portion is divided into a plurality of parts.

[0006] In the thrust bearing according to the aspect of the present disclosure, the lower foil portion may include a bottom foil portion including a first plate-like member that planarly supports a part of the bearing surface of the upper foil portion.

[0007] In a thrust bearing according to an aspect of the present disclosure, the lower foil portion may include a first support foil portion disposed below the bottom foil portion and including a plurality of first support members, a pad foil portion disposed below the first support foil portion and including a second plate-like member corresponding to the first plate-like member, and a second support foil portion disposed below the pad foil portion and including a plurality of second support members. The first plate-like member may be supported by two of the plurality of first support members. One of the two first support members may be supported by a part of the second plate-like member and two of the plurality of second support members. The other of the two first support members may be supported by a part different from the part of the second plate-like member, one of the two second support members, and a second support member different from the two second support members.

[0008] In a thrust bearing according to an aspect of the present disclosure, the lower foil portion may elastically support the upper foil portion such that the support stiffness of each of the plurality of portions on the upstream side in the rotation direction of the rotating member is less than the support stiffness of each of the plurality of portions on the downstream side in the rotation direction.

[0009] In a thrust bearing according to an aspect of the present disclosure, one of the two first support members may be disposed on the upstream side in the rotation direction of the other of the two first support members. The distance between the two second support members may be greater than the distance between one of the two second support members and a different second support member of the two second support members.

[0010] In a thrust bearing according to an aspect of the present disclosure, the thickness of the first plate-like member on the upstream side in the rotation direction may be less than the thickness of the first plate-like member on the downstream side in the rotation direction.

[0011] In a thrust bearing according to an aspect of the present disclosure, one of the two first support members may be disposed on the upstream side in the rotation direction of the other of the two first support members. The thickness of one of the two first support members may be less than the thickness of the other of the two first support members.

[0012] In the thrust bearing according to the solution of the present disclosure, the first plate-like member of the bottom foil portion may be disposed in the region surrounded by the first annular member. The bottom foil portion may further include a first annular member extending in the circumferential direction of the thrust bearing, and a first connecting member connecting the first annular member and the first plate-like member. The length along the shape of the first connecting member from the first connection point to the second connection point may be greater than the length of the straight line connecting the first connection point and the second connection point. The first connection point may be the connection point between the first annular member and the first connecting member. The second connection point may be the connection point between the first plate-like member and the first connecting member.

[0013] In the thrust bearing according to the solution of the present disclosure, the first support foil portion may include a second annular member extending in the circumferential direction of the thrust bearing, a first support member disposed in the region surrounded by the second annular member, and a second connecting member connecting the second annular member and one of the plurality of first support members. The length along the shape of the second connecting member from the third connection point to the fourth connection point may be greater than the length of the straight line connecting the third connection point and the fourth connection point. The third connection point may be the connection point between the second annular member and the second connecting member. The fourth connection point may be the connection point between one of the first support members and the second connecting member.

[0014] In the thrust bearing according to the solution of the present disclosure, a part of the second plate-like member and two second support members may define a two-end support beam structure that supports one of the two first support members. A part different from the part of the second plate-like member, one of the two second support members, and a second support member different from the two second support members may define a two-end support beam structure that supports the other of the two first support members. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The features, advantages, and technical and industrial significance of the exemplary embodiments of the present invention will be described hereinafter with reference to the accompanying drawings, in which like reference numerals represent like components, and in which:

[0016] Figure 1 is a perspective view showing the components constituting the thrust bearing according to an embodiment;

[0017] Figure 2A is a plan view showing the components constituting the thrust bearing according to an embodiment;

[0018] Figure 2B is a plan view showing the components constituting the thrust bearing according to an embodiment;

[0019] Figure 2C is a plan view showing the components constituting the thrust bearing according to an embodiment;

[0020] Figure 2D is a plan view showing the components constituting a thrust bearing according to an embodiment;

[0021] Figure 2E is a plan view showing the components constituting a thrust bearing according to an embodiment;

[0022] Figure 2F is a plan view showing the components constituting a thrust bearing according to an embodiment;

[0023] Figure 3A is a plan view of the thrust bearing observed from the top foil portion side;

[0024] Figure 3B is a cross-sectional view showing an example of a 3B-3B cross-section of a thrust bearing according to an embodiment;

[0025] Figure 4 shows an operation example of a thrust bearing according to an embodiment;

[0026] Figure 5A shows one mode of the plate-like member of the top foil portion according to an embodiment;

[0027] Figure 5B shows another mode of the plate-like member of the top foil portion according to an embodiment;

[0028] Figure 5C shows another mode of the plate-like member of the top foil portion according to an embodiment;

[0029] Figure 6A shows one connection mode between the annular member and the plate-like member of the bottom foil portion according to an embodiment;

[0030] Figure 6B shows another connection mode between the annular member and the plate-like member of the bottom foil portion according to an embodiment;

[0031] Figure 6C shows another connection mode between the annular member and the plate-like member of the bottom foil portion according to an embodiment;

[0032] Figure 6D shows another connection mode between the annular member and the plate-like member of the bottom foil portion according to an embodiment;

[0033] Figure 6E shows another connection mode between the annular member and the plate-like member of the bottom foil portion according to an embodiment;

[0034] Figure 6F shows another connection mode between the annular member and the plate-like member of the bottom foil portion according to an embodiment;

[0035] Figure 6G Shows another connection mode between the annular member and the plate-like member of the underlying foil portion according to an embodiment;

[0036] Figure 6H Shows another connection mode between the annular member and the plate-like member of the underlying foil portion according to an embodiment;

[0037] Figure 7A Shows a connection mode between the annular member of the support foil portion and the support member according to an embodiment;

[0038] Figure 7B Shows another connection mode between the annular member of the support foil portion and the support member according to an embodiment;

[0039] Figure 7C Shows another connection mode between the annular member of the support foil portion and the support member according to an embodiment;

[0040] Figure 7D Shows another connection mode between the annular member of the support foil portion and the support member according to an embodiment;

[0041] Figure 8A Shows a mode of the back foil structure according to an embodiment;

[0042] Figure 8B Shows another mode of the back foil structure according to an embodiment;

[0043] Figure 8C Shows another mode of the back foil structure according to an embodiment;

[0044] Figure 9A Shows an example of the shape of the support member of the support foil portion according to an embodiment;

[0045] Figure 9B Shows an example of the shape of the support member of the support foil portion according to an embodiment;

[0046] Figure 9C Shows an example of the shape of the support member of the support foil portion according to an embodiment;

[0047] Figure 10A Shows another example of the shape of the support member of the support foil portion according to an embodiment;

[0048] Figure 10B Shows another example of the shape of the support member of the support foil portion according to an embodiment;

[0049] Figure 11AIt is a plan view of a part of a thrust bearing according to an embodiment as observed from the top foil side;

[0050] Figure 11B It is a cross-sectional view showing another example of the cross-section of a thrust bearing according to an embodiment;

[0051] Figure 12A It shows a mode of the back foil structure according to an embodiment;

[0052] Figure 12B It shows another mode of the back foil structure according to an embodiment;

[0053] Figure 12C It shows another mode of the back foil structure according to an embodiment;

[0054] Figure 13A It is a plan view showing an example of a back plate according to an embodiment; and

[0055] Figure 13B It is a cross-sectional view of a thrust bearing including a back plate according to an embodiment. Detailed Description

[0056] Reference will be made to Figures 1 to 4 Describe the thrust bearing according to the first embodiment.

[0057] Reference will be made to Figures 1 to 2F Describe the structure of the thrust bearing 10 according to the first embodiment. Figure 1 It is a perspective view showing the components constituting the thrust bearing 10. Figures 2A to 2F It is a plan view showing the components constituting the thrust bearing 10.

[0058] In Figures 1 to 2F the thrust bearing 10 includes a top foil portion 11, a bottom foil portion 12, a support foil portion 13, a pad foil portion 14, a support foil portion 15, and a back plate 16.

[0059] Figure 1 The Z-axis direction in

[0060] As in Figure 2AAs shown, the top foil portion 11 includes six plate-like members 111. That is to say, the top foil portion 11 is divided into a plurality of members. The six plate-like members 111 define a bearing surface S that faces a rotating member (e.g., Figure 3B the rotating member 50 shown in

[0061] which) capable of rotating about a rotation axis. The plate-like members 111 may also be referred to as "blades". The number of the plate-like members 111 is not limited to six, and may be less than five, or more than seven. Figure 2B As shown, the bottom foil portion 12 includes an annular member 121 extending in the circumferential direction of the thrust bearing 10 and six plate-like members 122 arranged in the area surrounded by the annular member 121. The plate-like members 122 may also be referred to as "bottom foils". The number of the plate-like members 122 is not limited to six, and may be less than five, or more than seven. The number of the plate-like members 122 may correspond to the number of the plate-like members 111.

[0062] As shown, the support foil portion 13 includes an annular member 131 extending in the circumferential direction of the thrust bearing 10, and twelve support members 132 arranged in the area surrounded by the annular member 131 and extending toward the center of the thrust bearing 10. Two support members 132 may be treated as a group. The number of the support members 132 is not limited to twelve, and may be less than eleven, or more than thirteen. The number of the support members 132 may correspond to the number of the plate-like members 122. Figure 2C

[0063] As shown, the pad foil portion 14 includes an annular member 141 extending in the circumferential direction of the thrust bearing 10 and six plate-like members 142 arranged in the area surrounded by the annular member 141. The plate-like members 142 may also be referred to as "pad foils". The number of the plate-like members 142 is not limited to six, and may be less than five, or more than seven. The number of the plate-like members 142 may correspond to the number of the plate-like members 122. Figure 2D

[0064] As shown, the support foil portion 15 includes an annular member 151 extending in the circumferential direction of the thrust bearing 10, and eighteen support members 152 arranged in the area surrounded by the annular member 151 and extending toward the center of the thrust bearing 10. Three support members 152 may be treated as a group. The number of the support members 152 is not limited to eighteen, and may be less than seventeen, or more than nineteen. The number of the support members 152 may correspond to the number of the plate-like members 142. Figure 2E

[0065] The structure of the thrust bearing 10 will be further described with reference to Figure 3A 3B and Figure 3A and 3B . Figure 3Ais a plan view of the thrust bearing 10 as viewed from the top foil portion 11 side. Figure 3B is a cross-sectional view taken along Figure 3A the line 3B-3B in Figure 3A and 3B In Figure 3B and Figure 3B the arrow R indicates the rotation direction of the rotating member 50. In

[0066] As Figure 3B shown, the plate-like member 111 includes a tapered portion 1111 and a flat portion 1112. The tapered portion 1111 is inclined such that the distance between the tapered portion 1111 and the back plate 16 on the upstream side in the rotation direction is shorter than the distance between the tapered portion 1111 and the back plate 16 on the downstream side in the rotation direction. Since the plate-like member 111 extending along the surface of the back plate 16 facing the rotating member 50 includes the tapered portion 1111, the clearance between the thrust bearing 10 and the rotating member 50 decreases from the upstream side in the rotation direction to the downstream side in the rotation direction. That is, the plate-like member 111 and the rotating member 50 define a wedge-shaped flow path that tapers from the upstream side in the rotation direction to the downstream side in the rotation direction.

[0067] The structure defined by the shape of the plate-like member 111 may also be referred to as a "top foil structure". A top foil structure that defines a wedge-shaped flow path may also be referred to as a "sector". As described above, the top foil portion 11 includes six plate-like members 111. Therefore, the thrust bearing 10 includes six sectors.

[0068] The fluid (such as air) between the thrust bearing 10 and the rotating member 50 swirls in the circumferential direction of the thrust bearing 10 as the rotating member 50 rotates. As a result, a dynamic pressure is applied to the plate-like member 111 (i.e., the top foil portion 11) in the -Z direction. That is, a pressure for pressing the thrust bearing 10 is generated. The dynamic pressure is mainly applied to the flat portion 1112 of the plate-like member 111. Therefore, the flat portion 1112 may also be referred to as a "pressure-receiving surface".

[0069] The dynamic pressure applied to the plate-like member 111 is elastically borne by the back foil structure defined by the bottom foil portion 12, the support foil portion 13, the cushion foil portion 14, the support foil portion 15, and the back plate 16. The back foil structure provides the thrust bearing 10 with appropriate stiffness and damping properties related to the operating conditions of the rotating member 50 (such as the rotational speed of the rotating member 50). Therefore, the thrust bearing 10 absorbs at least one of the vibration and impact of the rotating member 50 in the direction in which the rotating member 50 presses the bearing in the direction of the rotation axis of the rotating member 50 (i.e., the thrust direction: Figure 3A and 3BMovement in the Z-axis direction). At this time, the gap between the thrust bearing 10 and the rotating member 50 is an appropriate gap related to the operating conditions of the rotating member 50.

[0070] The foil-type thrust bearing 10 withstands the dynamic pressure applied to the bearing surface S (i.e., the plate-like member 111) by allowing the deflection of the bearing surface S defined by the flexible plate-like member 111. The thrust bearing 10 has excellent stability characteristics due to the flexibility of the plate-like member 111 and can be used as a bearing for a rotating member (e.g., the rotating member 50) that rotates at a relatively high speed. Therefore, the thrust bearing 10 can be applied to devices and equipment in which the rotating member rotates at a high speed in a high-temperature environment, such as turbochargers and micro gas turbines.

[0071] As described above, the thrust bearing 10 includes a top foil portion 11 that defines the bearing surface S and a back foil structure that elastically withstands the dynamic pressure applied to the bearing surface S. Therefore, the top foil portion 11 that defines the bearing surface S can also be referred to as the "upper foil portion", and the bottom foil portion 12, the support foil portion 13, the cushion foil portion 14, the support foil portion 15, and the back plate 16 that define the back foil structure can also be referred to as the "lower foil portions". In this case, as the lower foil portions, the thrust bearing 10 can include the bottom foil portion 12, the support foil portion 13, the cushion foil portion 14, the support foil portion 15, and the back plate 16.

[0072] As Figure 3B shown, one plate-like member 122 of the bottom foil portion 12 is disposed below the flat portion 1112 of the plate-like member 111. Two support members 132#1 and 132#2 of the support foil portion 13 are disposed below one plate-like member 122. One plate-like member 142 of the cushion foil portion 14 is disposed below the two support members 132#1 and 132#2. Three support members 152#1, 152#2, and 152#3 of the support foil portion 15 are disposed below one plate-like member 142.

[0073] The thickness of the plate-like member 122 can be greater than the thickness of the plate-like member 111 and the thickness of the plate-like member 142. In other words, the stiffness of the plate-like member 122 can be higher than the stiffness of the plate-like members 111 and 142. With this configuration, even when dynamic pressure is applied to the plate-like member 111, the planarity of the flat portion 1112 of the plate-like member 111 can be maintained.

[0074] When dynamic pressure is applied to the plate-like member 111, the force applied to the support member 132#1 via the plate-like member 122 is elastically withstood by a two-end support beam structure defined by a part of the plate-like member 142 and the support members 152#1 and 152#2. That is, the force applied to the support member 132#1 is withstood by the elastic force generated when a part of the plate-like member 142 is deflected (i.e., elastically deformed).

[0075] When dynamic pressure is applied to the plate-like member 111, the force applied to the support member 132#2 via the plate-like member 122 is elastically borne by the other part of the plate-like member 142 and the both-end support beam structure defined by the support members 152#2 and 152#3. That is, the force applied to the support member 132#2 is borne by the elastic force generated when the other part of the plate-like member 142 is flexed (i.e., elastically deformed).

[0076] Next, the operation of the thrust bearing 10 will be described with reference to Figure 4 the following. Figure 4 An operation example of the thrust bearing 10 is shown. In Figure 4 the figure, the arrow R indicates the rotation direction of the rotating member 50. Figure 4 FIG. is a cross-sectional view of the thrust bearing taken along the line 3B-3B in Figure 3A the figure. In Figure 4 the figure, the dashed arrow indicates the movement of the fluid (e.g., air) between the thrust bearing 10 and the rotating member 50.

[0077] As Figure 4 shown, as the rotating member 50 rotates, the fluid moves along the circumferential direction of the thrust bearing 10. At this time, in the portion shown by the dashed circle CI1, the fluid is compressed by the wedge-shaped flow path defined by the tapered portion 1111 of the plate-like member 111 and the rotating member 50. Therefore, the compressed fluid is guided into the gap between the flat portion 1112 of the plate-like member 111 and the rotating member 50. As a result, a fluid film that bears the thrust in the thrust direction of the rotating member 50 is formed in the gap between the flat portion 1112 and the rotating member 50. Mainly in the portion shown by the dashed circle CI2, due to viscous heating, the temperature of the fluid (fluid film) rises.

[0078] For example, as Figure 3A shown, the plate-like member 111 has a chevron shape at the end on the downstream side in the rotation direction of the rotating member 50. Therefore, in Figure 4 the portion shown by the dashed circle CI3 in the figure, turbulence occurs due to the chevron shape. As a result, the fluid having a relatively high temperature after passing through the portion shown by the dashed circle CI2 is mixed with the fluid having a relatively low temperature and not passing through the portion shown by the dashed circle Cl2.

[0079] Technical Effects

[0080] When the relative speed between the thrust bearing 10 and the rotating member 50 is relatively high (e.g., when the rotating member 50 rotates at a relatively high speed), the temperature of the fluid film between the thrust bearing 10 and the rotating member 50 rises due to viscous heating. The relatively high temperature of the fluid film may reduce the load capacity of the thrust bearing 10.

[0081] As described with reference to Figure 4As described above, in the thrust bearing 10, turbulence occurs on the downstream side in the rotation direction of the plate-like member 111 (see the dashed circle CI3 in Figure 4 ). Therefore, the fluid having a relatively high temperature passing through the portion indicated by the dashed circle CI2 in Figure 4 is mixed with the fluid having a relatively low temperature and not passing through the portion shown by the dashed circle CI2. That is, the thrust bearing 10 can reduce the temperature of the fluid guided into the gap between the rotating member 50 and the flat portion 1112 of the other plate-like member 111 on the lower side in the rotation direction of one plate-like member 111. As a result, in the thrust bearing 10, an increase in the temperature of the fluid film is suppressed. Therefore, the thrust bearing 10 can suppress a decrease in load capacity.

[0082] As described above, the thrust bearing 10 includes two two-end supported beam structures, that is, the two-end supported beam structure defined by a part of the plate-like member 142 and the support members 152#1 and 152#2, and the two-end supported beam structure defined by another part of the plate-like member 142 and the support members 152#2 and 152#3. That is, in the thrust bearing 10, one plate-like member 111 is elastically supported by two two-end supported beam structures. In other words, each sector of the thrust bearing 10 includes two two-end supported beam structures.

[0083] By adjusting the distance (i.e., pitch) between the support members 152#1 and 152#2, the amount of deflection of a part of the plate-like member 142 when a force is applied to a part of the plate-like member 142 can be adjusted. Similarly, by adjusting the distance between the support members 152#2 and 152#3, the amount of deflection of another part of the plate-like member 142 when a force is applied to another part of the plate-like member 142 can be adjusted. As a result, in the thrust bearing 10, the degree of freedom of the elasticity provided to the back foil structure can be increased. Therefore, an appropriate elasticity related to the specifications of the device or equipment to which the thrust bearing 10 is applied can be provided to the back foil structure.

[0084] As described above, the thickness of the plate-like member 122 of the bottom foil portion 12 can be greater than the thickness of the plate-like member 111 of the top foil portion 11 and the thickness of the plate-like member 142 of the pad foil portion 14. With this configuration, even when hydrodynamic pressure is applied to the plate-like member 111, the flatness of the flat portion 1112 of the plate-like member 111 can be maintained.

[0085] Second Embodiment

[0086] The thrust bearing according to the second embodiment will be described with reference to Figures 5A to 5C . In the second embodiment, descriptions that are repeated with those of the first embodiment will be appropriately omitted. Figures 5A to 5C Various modes of the plate-like member (e.g., the plate-like member 111) of the top foil portion 11 are shown. In Figures 5A to 5CIn the figure, the arrow R indicates the rotation direction of the rotating member (for example, the rotating member 50).

[0087] Figure 5A is a plan view showing a plate-like member 111 according to the first embodiment. As Figure 5A shown, the end portion on the downstream side in the rotation direction of the plate-like member 111 has a chevron shape. Due to this chevron shape, when the rotating member rotates, turbulence occurs on the downstream side in the rotation direction of the plate-like member 111.

[0088] The plate-like member of the top foil portion 11 is not limited to Figure 5A the plate-like member 111 shown, as long as it has a structure that causes turbulence when the rotating member rotates.

[0089] The plate-like member of the top foil portion 11 can be, for example, Figure 5B the plate-like member 111a shown. A plurality of openings 1113 are formed near the end portion on the downstream side in the rotation direction of the plate-like member 111a. In other words, holes are formed near the end portion on the downstream side in the rotation direction of the plate-like member 111a. The openings 1113 can be formed in the plate-like member 111a by punching using a die. When the rotating member rotates, the openings 1113 cause turbulence on the downstream side in the rotation direction of the plate-like member 111a.

[0090] For example, the plate-like member of the top foil portion 11 can be Figure 5C the plate-like member 111b shown. The surface roughness of the surface 1114 near the end portion on the downstream side in the rotation direction of the plate-like member 111b is higher than the surface roughness of other portions of the plate-like member 114b. For example, the surface roughness of the surface 1114 can be made higher than the surface roughness of other portions of the plate-like member 111b by at least one of etching, sandblasting, and shot peening. Due to the surface roughness of the surface 1114, when the rotating member rotates, turbulence occurs on the downstream side in the rotation direction of the plate-like member 111b.

[0091] Technical effects

[0092] With a relatively simple structure or process, when the rotating member rotates, the plate-like members 111, 111a, and 111b cause turbulence. Therefore, the plate-like members 111, 111a, and 111b can suppress the temperature rise of the fluid film. Therefore, the plate-like members 111, 111a, and 111b can suppress the reduction of the load capacity of the thrust bearing 10.

[0093] Third embodiment

[0094] The thrust bearing according to the third embodiment will be described with reference to Figures 6A to 6H In the third embodiment, descriptions that are repetitive with those of the first embodiment will be appropriately omitted. Figures 6A to 6HShows various connection modes between the annular member 121 and the plate-like member 122 of the underlying foil portion 12.

[0095] As Figure 6A shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123. The annular member 121 and the connecting member 123 are connected at the connection point A. The plate-like member 122 and the connecting member 123 are connected at the connection point B. The connecting member 123 is formed such that the length along the shape of the connecting member 123 from the connection point A to the connection point B (i.e., Figure 6A the length of the dash line in Figure 6A ) is greater than the length of the straight line connecting the connection point A and the connection point B (

[0096] As Figure 6B shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123a. The annular member 121 and the connecting member 123a are connected at the connection point A. The plate-like member 122 and the connecting member 123a are connected at the connection point B. The connecting member 123a is formed such that the length along the shape of the connecting member 123b from the connection point A to the connection point B (i.e., Figure 6B the length of the dash line in Figure 6B ) is greater than the length of the straight line connecting the connection point A and the connection point B (

[0097] As Figure 6C shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123b. The annular member 121 and the connecting member 123b are connected at the connection point A. The plate-like member 122 and the connecting member 123b are connected at the connection point B. The connecting member 123b is formed such that the length along the shape of the connecting member 123b from the connection point A to the connection point B (i.e., Figure 6C the length of the dash line in Figure 6C ) is greater than the length of the straight line connecting the connection point A and the connection point B (

[0098] As Figure 6D shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123c. The annular member 121 and the connecting member 123c are connected at the connection point A. The plate-like member 122 and the connecting member 123c are connected at the connection point B. The connecting member 123c is formed such that the length along the shape of the connecting member 123c from the connection point A to the connection point B (i.e., Figure 6D the length of the dash line in Figure 6D ) is greater than the length of the straight line connecting the connection point A and the connection point B (

[0099] As Figure 6EAs shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123d. The annular member 121 and the connecting member 123d are connected at a connection point A. The plate-like member 122 and the connecting member 123d are connected at a connection point B. The connecting member 123d is formed such that the length along the shape of the connecting member 123d from the connection point A to the connection point B (i.e., Figure 6E the length of the dash line in Figure 6E ) is greater than the length of the straight line connecting the connection point A and the connection point B (

[0100] the length of the dotted line in Figure 6F ). Figure 6F As shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123e. The annular member 121 and the connecting member 123e are connected at a connection point A. The plate-like member 122 and the connecting member 123e are connected at a connection point B. The connecting member 123e is formed such that the length along the shape of the connecting member 123e from the connection point A to the connection point B (i.e., Figure 6F the length of the dash line in

[0101] ) is greater than the length of the straight line connecting the connection point A and the connection point B ( Figure 6G the length of the dotted line in Figure 6G ). Figure 6G As shown, the annular member 121 and the plate-like member 122 can be connected by a connecting member 123f. The annular member 121 and the connecting member 123f are connected at a connection point A. The plate-like member 122 and the connecting member 123f are connected at a connection point B. The connecting member 123f is formed such that the length along the shape of the connecting member 123f from the connection point A to the connection point B (i.e.,

[0102] ) is greater than the length of the straight line connecting the connection point A and the connection point B ( Figure 6H ) is greater than the length of the straight line connecting the connection point A and the connection point B ( Figure 6H the length of the dash line in Figure 6H the dotted line distance of

[0103] Technical effects

[0104] When dynamic pressure generated as a rotating member (e.g., rotating member 50) rotates is applied to the top foil portion 11 (e.g., plate-like member 111) and there is a difference in stiffness between the outer peripheral side (i.e., the side of the annular member 121) and the inner peripheral side of the plate-like member 122, the load capacity of the thrust bearing 10 decreases.

[0105] The connecting member is formed such that the length along the shape of the connecting member from the connection point A to the connection point B is greater than the length of the straight line between the connection point A and the connection point B. Therefore, the occurrence of a difference in stiffness between the outer peripheral side and the inner peripheral side of the plate-like member 122 can be suppressed. Thus, for example, it is not necessary to change the thickness of the plate-like member 122 within the plate-like member 122 to suppress the occurrence of the stiffness difference. As a result, for example, even when dynamic pressure is applied to the top foil portion 11, the planarity of the plate-like member 122 can be maintained. Therefore, the connecting members 123, 123a, 123b, 123c, 123d, 123e, 123f, and 123g can improve the load capacity of the thrust bearing 10.

[0106] Fourth Embodiment

[0107] will be referred to Figures 7A to 7D to describe the thrust bearing according to the fourth embodiment. In the fourth embodiment, descriptions that overlap with those of the first embodiment will be appropriately omitted. Figures 7A to 7D Various connection modes between the annular member 131 supporting the foil portion 13 and the support member 132 are shown.

[0108] As Figure 7A shown, the annular member 131 and each of the support members 132#1 and 132#2 can be connected by a connecting member 133. The annular member 131 and the connecting member 133 are connected at a connection point C. The support member 132#1 and the connecting member 133 are connected at a connection point D1. The support member 132#2 and the connecting member 133 are connected at a connection point D2. The connecting member 133 is formed such that the length along the shape of the connecting member 133 from the connection point C to the connection point D1 (i.e., Figure 7A the length of the dashed line in) is greater than the length of the straight line connecting the connection point C and the connection point D1 ( Figure 7A the length of the dotted line in). The connecting member 133 is formed such that the length along the shape of the connecting member 133 from the connection point C to the connection point D2 (i.e., Figure 7A the length of the dashed line in) is greater than the length of the straight line connecting the connection point C and the connection point D2 ( Figure 7A the length of the dotted line in).

[0109] As Figure 7BAs shown, the annular member 131 and the support member 132#1 can be connected by a connecting member 133a#1. The annular member 131 and the support member 132#2 can be connected by a connecting member 133a#2. The annular member 131 and the connecting member 133a#1 are connected at a connection point C1. The support member 132#1 and the connecting member 133a#1 are connected at a connection point D1. The annular member 131 and the connecting member 133a#2 are connected at a connection point C2. The support member 132#2 and the connecting member 133a#2 are connected at a connection point D2. The connecting member 133a#1 is formed such that the length along the shape of the connecting member 133a#1 from the connection point C1 to the connection point D1 (i.e., Figure 7B the length of the dash line in) is greater than the length of the straight line connecting the connection point C1 and the connection point D1 ( Figure 7B the length of the dotted line in). The connecting member 133a#2 is formed such that the length along the shape of the connecting member 133a#2 from the connection point C2 to the connection point D2 (i.e., Figure 7B the length of the dash line in) is greater than the length of the straight line connecting the connection point C2 and the connection point D2 ( Figure 7B the length of the dotted line in).

[0110] As Figure 7C shown, each of the annular member 131 and the support members 132#1 and 132#2 can be connected by a connecting member 133b. The annular member 131 and the connecting member 133b are connected at connection points C1 and C2. The support member 132#1 and the connecting member 133b are connected at a connection point D1. The support member 132#2 and the connecting member 133b are connected at a connection point D2. The connecting member 133b is formed such that the length along the shape of the connecting member 133b from the connection point C1 to the connection point D1 (i.e., Figure 7C the length of the dash line in) is greater than the length of the straight line connecting the connection point C1 and the connection point D1 ( Figure 7C the length of the dotted line in). The connecting member 133b is formed such that the length along the shape of the connecting member 133b from the connection point C2 to the connection point D2 (i.e., Figure 7C the length of the dash line in) is greater than the length of the straight line connecting the connection point C2 and the connection point D2 ( Figure 7C the length of the dotted line in).

[0111] As Figure 7DAs shown, each of the annular member 131 and the support members 132#1 and 132#2 can be connected by a connecting member 133c. The annular member 131 and the connecting member 133c are connected at connection points C1 and C2. The support member 132#1 and the connecting member 133c are connected at a connection point D1. The support member 132#2 and the connecting member 133c are connected at a connection point D2. The connecting member 133c is formed such that the length along the shape of the connecting member 133c from the connection point C1 to the connection point D1 (i.e., Figure 7D the length of the dash line in Figure 7D ) is greater than the length of the straight line connecting the connection point C1 and the connection point D1 ( Figure 7D the length of the dotted line in Figure 7D ). The connecting member 133c is formed such that the length along the shape of the connecting member 133c from the connection point C2 to the connection point D2 (i.e.,

[0112] Technical effects

[0113] When the dynamic pressure generated with the rotation of a rotating member (e.g., the rotating member 50) is applied to the top foil portion 11 (e.g., the plate-like member 111) and there is a stiffness difference between the outer peripheral side (i.e., the annular member 131 side) and the inner peripheral side of the support member 132, the load capacity of the thrust bearing 10 decreases.

[0114] The connecting member is formed such that the length along the shape of the connecting member from the connection point C or C1 to the connection point D1 is greater than the length of the straight line connecting the connection point C or C1 and the connection point D1. Accordingly, the occurrence of a stiffness difference between the outer peripheral side and the inner peripheral side of the support member 132#1 can be suppressed. Similarly, the connecting member is formed such that the length along the shape of the connecting member from the connection point C or C2 to the connection point D2 is greater than the length of the straight line connecting the connection point C or C2 and the connection point D2. Accordingly, the occurrence of a stiffness difference between the outer peripheral side and the inner peripheral side of the support member 132#2 can be suppressed. As a result, for example, even when dynamic pressure is applied to the top foil portion 11, the planarity of the support members 132#1 and 132#2 can be maintained. Thus, the connecting members 133, 133a, 133b, and 133c can improve the load capacity of the thrust bearing 10.

[0115] Fifth embodiment

[0116] A thrust bearing according to the fifth embodiment will be described with reference to Figures 8A to 8C . In the fifth embodiment, descriptions that overlap with those of the first embodiment will be appropriately omitted. Figures 8A to 8C Various modes of the back foil structure are shown. Figures 8A to 8Ccorresponding to a cross-sectional view taken along line 3B-3B in Figure 3A As shown in FIG.

[0117] As shown in Figure 8A the thrust bearing 10 may include two end-supported beam structures, namely, an end-supported beam structure defined by a part of the plate-like member 142 and the support members 152#1 and 152#2, and an end-supported beam structure defined by another part of the plate-like member 142 and the support members 152#2 and 152#3.

[0118] As shown in Figure 8B the thrust bearing 10a may include three end-supported beam structures, namely, an end-supported beam structure defined by a part of the plate-like member 142 and the support members 152#1 and 152#2, an end-supported beam structure defined by another part of the plate-like member 142 and the support members 152#2 and 152#3, and an end-supported beam structure defined by another part of the plate-like member 142 and the support members 152#3 and 152#4.

[0119] Figure 8C The thrust bearing 10b shown in FIG. may include an additional cushion foil portion disposed below the support foil portion 15 and including a plate-like member 242 corresponding to the plate-like member 142, and an additional support foil portion disposed below the additional cushion foil portion and including support members 252#1, 252#2, 252#3, and 252#4 corresponding to the support members 152.

[0120] As shown in Figure 8C the thrust bearing 10b may include five end-supported beam structures, namely, an end-supported beam structure defined by a part of the plate-like member 142 and the support members 152#1 and 152#2, an end-supported beam structure defined by another part of the plate-like member 142 and the support members 152#2 and 152#3, an end-supported beam structure defined by a part of the plate-like member 242 and the support members 252#1 and 252#2, an end-supported beam structure defined by another part of the plate-like member 242 and the support members 252#2 and 252#3, and an end-supported beam structure defined by another part of the plate-like member 242 and the support members 252#3 and 252#4.

[0121] Technical effects

[0122] As shown in Figures 8A to 8CAs shown, each sector of the thrust bearings 10, 10a, and 10b may include more than two two-end support beam structures. With this configuration, the degree of freedom in providing elasticity to the back foil structure can be increased. For example, when applied to a relatively large rotating device, the thrust bearing can also be increased in size. Therefore, it is relatively easy to increase the number of two-end support beam structures in each sector. Thus, as the size of the thrust bearing increases, the degree of freedom in providing elasticity to the back foil structure can be increased.

[0123] Sixth Embodiment

[0124] will be described with reference to Figures 9A to 9C the thrust bearing according to the sixth embodiment. In the sixth embodiment, descriptions that overlap with those of the first embodiment will be appropriately omitted. Figures 9A to 9C The shape of the support member 132 that supports the support foil portion 13 is shown.

[0125] Figure 9B is a view showing Figure 9A a plan view of a set of support members 132#1 and 132#2 of the support foil portion 13 shown. In Figure 9B it, the point O represents the center of the support foil portion 13 (i.e., the center of the rotation axis of the rotating member).

[0126] In Figure 9B it, the support member 132#1 may have a sector shape around the point O 1 and the support member 132#2 may have a sector shape around the point O 2 The points O 1 and O 2 may be points on the circumference of a circle around the point O.

[0127] Technical Effects

[0128] If each of the support members 132#1 and 132#2 has a sector shape around the point O, then as shown Figure 9C (see the symbols "Pi" and "Po" in Figure 9C ), the distance (i.e., the pitch) between the support members 132#1 and 132#2 increases toward the outer peripheral side of the support members 132#1 and 132#2. In this back foil structure, the stiffness of the inner peripheral side where the distance between the support members 132#1 and 132#2 is relatively short is higher than the stiffness of the outer peripheral side where the distance between the support members 132#1 and 132#2 is relatively long. Due to the difference in stiffness between the inner peripheral side and the outer peripheral side of the support members 132#1 and 132#2, the flatness of the flat portion 1112 of the top foil portion 11 is reduced. As a result, the load capacity of the thrust bearing 10 is reduced.

[0129] As shown in Figure 9BAs shown, when the support member 132#1 has a sector shape around the point O 1 and the support member 132#2 has a sector shape around the point O 2 , the distance Pi on the inner peripheral side between the support members 132#1 and 132#2 and the distance Po on the outer peripheral side between the support members 132#1 and 132#2 can be made closer to each other (usually equal). As a result, the occurrence of a stiffness difference between the inner peripheral side and the outer peripheral side of the support members 132#1 and 132#2 can be suppressed. Therefore, Figure 9B the support members 132#1 and 132#2 shown can suppress a decrease in the load capacity of the thrust bearing 10.

[0130] Seventh Embodiment

[0131] The thrust bearing according to the seventh embodiment will be described with reference to Figure 10A and 10B . In the seventh embodiment, descriptions that overlap with those of the first embodiment will be appropriately omitted. Figure 10A and 10B show the shape of the support member 152 of the support foil portion 15.

[0132] Figure 10B is a plan view showing a set of support members 152#1, 152#2, and 152#3 of the support foil portion 15 shown in Figure 10A . In Figure 10B , the point O represents the center of the support foil portion 15 (i.e., the center of the rotation axis of the rotating member).

[0133] In Figure 10B , the support member 152#1 can have a sector shape around the point O 3 . The support member 152#2 can have a sector shape around the point O 4 . The support member 152#3 can have a sector shape around the point O 5 . The points O 3 , O 4 and O 5 can be points on the circumference of a circle around the point O.

[0134] Technical Effects

[0135] If each of the support members 152#1, 152#2, and 152#3 has a sector shape around the point O, the distance (i.e., pitch) between the support members 152#1 and 152#2 increases toward the outer peripheral side of the support members 152#1 and 152#2 (for example, see Figure 9C)。Similarly, the distance between the support members 152#2 and 152#3 increases toward the outer peripheral sides of the support members 152#3 and 152#2. In the back foil structure, the stiffness of the inner peripheral side where the distance between the two support members 152 is relatively short is higher than the stiffness of the outer peripheral side where the distance between the two support members 152 is relatively long. Due to the difference in stiffness between the inner peripheral side and the outer peripheral side of the support member 152, the flatness of the flat portion 1112 of the top foil portion 11 is reduced. As a result, the load capacity of the thrust bearing 10 is reduced.

[0136] As Figure 10B shown, when the support member 152#1 has a sector shape around the point O 3 and the support member 152#2 has a sector shape around the point O 4 and the support member 152#3 has a sector shape around the point O 5 , the distance Pi on the inner peripheral side between the two support members 152 and the distance Po on the outer peripheral side between the two support members 152 can be made closer to each other (usually equal). As a result, the occurrence of the difference in stiffness between the inner peripheral side and the outer peripheral side of the support member 152 can be suppressed. Therefore, Figure 10B the support members 152#1, 152#2, and 152#3 shown can suppress the reduction in the load capacity of the thrust bearing 10.

[0137] Eighth Embodiment

[0138] will be described with reference to Figure 11A and 11B . In the eighth embodiment, descriptions that overlap with those of the first embodiment will be appropriately omitted. Figure 11A is a plan view of a part of the thrust bearing 10 as viewed from the top foil portion 11 side. Figure 11B is a cross-sectional view taken along the line 11B-11B in Figure 11A . In Figure 11B , the arrow R indicates the rotation direction of the rotating member 50. In Figure 11B , the respective layers and respective members are shown at different scales so that they can be identified on the drawing.

[0139] As in the first embodiment, by adjusting the distance between the support members 152#1 and 152#2 ( Figure 11A and 11B the pitch PA in), the amount of deflection of a part of the plate-like member 142 when a force is applied to a part of the plate-like member 142 can be adjusted. Similarly, by adjusting the distance between the support members 152#2 and 152#3 ( Figure 11A and 11B the pitch PB in), the amount of deflection of another part of the plate-like member 142 when a force is applied to another part of the plate-like member 142 can be adjusted.

[0140] For example, as Figure 11B shown, when the pitch PA is greater than the pitch PB, the amount of deflection of a part of the plate-like member 142 when a force is applied to a part of the plate-like member 142 is greater than the amount of deflection of another part of the plate-like member 142 when the same force as that applied to a part of the plate-like member 142 is applied to another part of the plate-like member 142. That is, when the pitch PA is greater than the pitch PB, the stiffness of the back foil structure on the upstream side in the rotational direction is lower than the stiffness of the back foil structure on the downstream side in the rotational direction. In other words, when the pitch PA is greater than the pitch PB, the stiffness of the back foil structure on the downstream side in the rotational direction is higher than the stiffness of the back foil structure on the upstream side in the rotational direction. As a result, when the dynamic pressure generated as the rotating member 50 rotates is applied to the plate-like member 111 of the top foil portion 11, the flat portion 1112 of the plate-like member 11 is inclined such that the flat portion 1112 is closer to the back plate 16 on the upstream side in the rotational direction than on the downstream side in the rotational direction, as Figure 11B indicated by the double-dashed line in

[0141] As the pitch PA becomes more greater than the pitch PB, the stiffness of the back foil structure on the upstream side in the rotational direction becomes even lower than the stiffness of the back foil structure on the downstream side in the rotational direction, and the difference between the stiffness of the back foil structure on the upstream side in the rotational direction and the stiffness of the back foil structure on the downstream side in the rotational direction increases. As the pitch PA approaches the pitch PB from a state where the pitch PA is less than the pitch PB, the difference between the stiffness of the back foil structure on the upstream side in the rotational direction and the stiffness of the back foil structure on the downstream side in the rotational direction decreases. As the difference between the stiffness of the back foil structure on the upstream side in the rotational direction and the stiffness of the back foil structure on the downstream side in the rotational direction decreases, the degree of inclination of the flat portion 1112 decreases.

[0142] Technical effect

[0143] According to the research conducted by the inventors of the present disclosure, the optimal shape of the gap between the plate-like member 111 and the rotating member 50 (i.e., the optimal wedge shape of the flow path) varies according to the rated rotational speed (i.e., the design rotational speed) of the rotating member 50. Specifically, when the rated rotational speed of the rotating member 50 is relatively low, the flat portion 1112 of the plate-like member 111 is preferably inclined such that the upstream side in the rotational direction of the flat portion 1112 is closer to the back plate 16 than the downstream side in the rotational direction of the flat portion 1112, as Figure 11B indicated by the double-dashed line in

[0144] As described above, by changing the pitch PA and the pitch PB, the respective stiffnesses of the upstream side and the downstream side in the rotation direction of the back foil structure can be changed. For example, when the pitch PA is set to be greater than the pitch PB, the shape of the gap between the plate-like member 111 and the rotating member 50 can be adapted to the case where the rated rotational speed of the rotating member 50 is relatively low. For example, when the pitch PA is set to be equal to the pitch PB, the shape of the gap between the plate-like member 111 and the rotating member 50 can be adapted to the case where the rated rotational speed of the rotating member 50 is relatively high.

[0145] According to the present embodiment, by changing the pitch PA and the pitch PB, the shape of the gap (i.e., the wedge shape of the flow path) between the plate-like member 111 and the rotating member 50 can be adjusted relatively easily. As a result, the shape of the gap between the plate-like member 111 and the rotating member 50 can be optimized for the rated rotational speed of the rotating member 50.

[0146] Ninth Embodiment

[0147] will be described with reference to Figures 12A to 12C a thrust bearing according to the ninth embodiment. In the ninth embodiment, descriptions that are repetitive with those of the first embodiment will be appropriately omitted. Figures 12A to 12C Various modes of the back foil structure are shown. In Figures 12A to 12C it, the arrow R indicates the rotation direction of the rotating member (for example, the rotating member 50). Figures 12A to 12C is a cross-sectional view corresponding to the cross-section taken along the line 3B-3B in Figure 3A and the respective layers and respective members are shown at different scales so as to be recognizable on the drawing.

[0148] In the eighth embodiment, the shape of the gap between the plate-like member 111 and the rotating member 50 can be adjusted by adjusting the pitch PA (i.e., the distance between the support members 152#1 and 152#2) and the pitch PB (the distance between the support members 152#2 and 152#3).

[0149] In the ninth embodiment, the shape of the gap between the plate-like member 111 and the rotating member 50 is adjusted by adjusting the members that define the back foil structure. As Figure 12A shown, the thrust bearing 10d may include a plate-like member 122a whose thickness on the upstream side in the rotation direction is smaller than the thickness on the downstream side in the rotation direction. When hydrodynamic pressure generated as the rotating member rotates is applied to the plate-like member 111 of the top foil portion 11, due to the difference between the thickness of the plate-like member 122a on the upstream side in the rotation direction and the thickness of the plate-like member 122a on the downstream side in the rotation direction, the upstream side of the flat portion 1112 of the plate-like member 111 is pressed toward the back plate 16 as compared with the downstream side of the flat portion 1112.

[0150] As Figure 12B shown, in thrust bearing 10e, the thickness of support member 132#1 arranged on the upstream side in the rotation direction can be smaller than the thickness of support member 132#2 arranged on the downstream side in the rotation direction. When hydrodynamic pressure generated with the rotation of the rotating member is applied to plate-like member 111 of top foil portion 11, due to the thickness difference between support members 132#1 and 132#2, the upstream side in the rotation direction of flat portion 1112 of plate-like member 11 is pressed toward back plate 16 as compared with the downstream side in the rotation direction of flat portion 1112.

[0151] As Figure 12C shown, thrust bearing 10f can include member 17, which corresponds to support member 132 and is arranged between plate-like member 122 of bottom foil portion 12 and support member 132#2 of support foil portion 13. When hydrodynamic pressure generated with the rotation of the rotating member is applied to plate-like member 111 of top foil portion 11, due to member 17, the upstream side in the rotation direction of flat portion 1112 of plate-like member 11 is pressed toward back plate 16 as compared with the downstream side in the rotation direction of flat portion 1112.

[0152] Technical effects

[0153] As described above, in thrust bearings 10d, 10e, and 10f, when hydrodynamic pressure generated with the rotation of the rotating member is applied to plate-like member 111 of top foil portion 11, the upstream side in the rotation direction of flat portion 1112 of plate-like member 11 is pressed toward back plate 16 as compared with the downstream side in the rotation direction of flat portion 1112. That is, flat portion 1112 is inclined due to the hydrodynamic pressure, such that the upstream side in the rotation direction of flat portion 112 is closer to back plate 16 than the downstream side in the rotation direction of flat portion 1112.

[0154] As in the eighth embodiment, for example, when the rated rotational speed of the rotating member is relatively low, flat portion 1112 is preferably inclined such that the upstream side in the rotation direction of flat portion 1112 is closer to back plate 16 than the downstream side in the rotation direction of flat portion 1112, as Figure 11B shown by the double-dashed line in. Through thrust bearings 10d, 10e, and 10f, the shape of the gap between plate-like member 111 and the rotating member can be suitable for the case where the rated rotational speed of the rotating member is relatively low.

[0155] Tenth embodiment

[0156] A thrust bearing according to the tenth embodiment will be described with reference to Figure 13A and 13B . In the tenth embodiment, descriptions that are repetitive with those of the first embodiment will be appropriately omitted. Figure 13A is a plan view showing back plate 16a. Figure 13Bis a cross-sectional view of the thrust bearing 10g including the back plate 16a taken along line 3B-3B (see Figure 3A ). In Figure 13B , the respective layers and respective components are shown at different scales so that they can be identified on the drawing.

[0157] As Figure 13A shown, the back plate 16a includes 12 protrusions 161 formed on the surface facing the rotating member (e.g., the rotating member 50). In the back plate 16a, each protrusion 161 is formed at a position overlapping with each support member 132 of the support foil portion 13 in the plan view of the thrust bearing 10g from the side of the top foil portion 11. The number of protrusions 161 is not limited to 12, but may be less than 11 or more than 13. The number of protrusions 161 may correspond to the number of support members 132.

[0158] As Figure 13B shown, in the plan view of the thrust bearing 10g from the side of the top foil portion 11, the protrusion 161#1 may be formed at a position overlapping with the support member 132#1. The protrusion 161#2 may be formed at a position overlapping with the support member 132#2 in the plan view of the thrust bearing 10g from the side of the top foil portion 11.

[0159] Technical effects

[0160] When the dynamic pressure generated with the rotation of the rotating member (e.g., the rotating member 50) is applied to the plate-like member 111 of the top foil portion 11, a force is applied to a part of the plate-like member 142 via the support member 132#1 to flex a part of the plate-like member 142, and a force is applied to another part of the plate-like member 142 via the support member 132#2 to flex another part of the plate-like member 142. As a result, the height of the thrust bearing 10g (i.e., the distance in the Z-axis direction) decreases.

[0161] In the thrust bearing 10g, the amount of flexure of a part of the plate-like member 142 and the amount of flexure of another part of the plate-like member 142 can be restricted by the protrusions 161 (e.g., the protrusions 161#1 and 161#2). That is, in the thrust bearing 10g, the protrusions 161 can control the amount of change in the height of the thrust bearing 10g. For example, by controlling the height of the protrusions 161, the amount of change in the height of the thrust bearing 10g can be controlled in units of micrometers.

[0162] When the height of the thrust bearing 10g changes, the distance between the rotating member and the stationary member also changes. As described above, by controlling the height of the protrusion 161, the amount of change in the height of the thrust bearing 10g can be controlled in units of micrometers. Therefore, the thrust bearing 10g can control the distance between the rotating member and the stationary member in units of micrometers. Therefore, the thrust bearing 10g can control the distance between the rotating member and the stationary member with high precision with a relatively simple structure.

[0163] Each aspect of the present disclosure derived from the above embodiments will be described below.

[0164] The thrust bearing according to one aspect of the present disclosure includes an upper foil portion and a lower foil portion. The upper foil portion includes a bearing surface facing a rotating member that can rotate about a rotation axis. The lower foil portion elastically supports the upper foil portion. The upper foil portion is divided into a plurality of parts. In the above embodiment, the "top foil portion 11" is an example of the "upper foil portion", and the "bottom foil portion 12", "support foil portion 13", "pad foil portion 14", "support foil portion 15", and "back plate 16" are examples of the "lower foil portion". In the above embodiment, the "plurality of plate-like members 111" is an example of the "plurality of parts".

[0165] The thrust bearing may include a bottom foil portion as the lower foil portion. The bottom foil portion includes a first plate-like member that flatly supports a part of the bearing surface of the upper foil portion.

[0166] In this aspect, the lower foil portion may include a first support foil portion disposed below the bottom foil portion and including a plurality of first support members, a pad foil portion disposed below the first support foil portion and including a second plate-like member corresponding to the first plate-like member, and a second support foil portion disposed below the pad foil portion and including a plurality of second support members. The first plate-like member may be supported by two first support members among the plurality of first support members. One of the two first support members may be supported by a part of the second plate-like member and two second support members among the plurality of second support members. The other of the two first support members may be supported by another part of the second plate-like member, one of the two second support members, and another second support member different from the two second support members among the plurality of second support members.

[0167] In this aspect, the lower foil portion may elastically support the upper foil portion such that the support stiffness of each of the plurality of parts on the upstream side in the rotation direction of the rotating member is less than (i.e., lower than) the support stiffness of each of the plurality of parts on the downstream side in the rotation direction.

[0168] In this solution, one of the first support members may be arranged on the upstream side in the rotational direction of the other first support member, and the distance between the two second support members may be greater than the distance between one second support member and the other second support member. In the above embodiment, "pitch PA" is an example of "the distance between the two second support members", and "pitch PB" is an example of "the distance between one second support member and the other second support member".

[0169] Alternatively, the thickness of the first plate-like member on the upstream side in the rotational direction may be smaller than the thickness of the first plate-like member on the downstream side in the rotational direction. Alternatively, one of the first support members may be arranged on the upstream side in the rotational direction of the other first support member, and the thickness of one first support member may be smaller than the thickness of the other first support member.

[0170] In the solution where the bottom foil part is set as the lower foil part, the bottom foil part may include a first annular member extending in the circumferential direction of the thrust bearing, the first plate-like member arranged in the area surrounded by the annular member, and a first connecting member connecting the first annular member and the first plate-like member. The length along the shape of the first connecting member from the first connection point between the first annular member and the first connecting member to the second connection point between the first plate-like member and the first connecting member may be greater than the length of the straight line connecting the first connection point and the second connection point.

[0171] In the solution where the first support foil part is set as the lower foil part, the first support foil part may include a second annular member extending in the circumferential direction of the thrust bearing, the first support member arranged in the area surrounded by the annular member, and a second connecting member connecting the second annular member and one of the plurality of first support members. The length along the shape of the second connecting member from the third connection point between the second annular member and the second connecting member to the fourth connection point between the one first support member and the second connecting member may be greater than the length of the straight line connecting the third connection point and the fourth connection point.

[0172] In the solution where the first support foil part, the pad foil part, and the second support foil part are set as the lower foil part, the part of the second plate-like member and the two second support members may define a two-end support beam structure for supporting the two ends of the one first support member, and the other part of the second plate-like member, the one second support member, and the other second support member may define a two-end support beam structure for supporting the two ends of the other first support member.

[0173] The present disclosure is not limited to the above embodiments, but can be appropriately modified without departing from the gist or spirit of the present disclosure that can be read from the entire claims and the specification, and the thrust bearing with such a modification is also included within the technical scope of the present disclosure.

Claims

1. A thrust bearing, characterized in that: include: an upper foil portion including a bearing surface facing a rotating member rotatable about a rotation axis; as well as a lower foil portion elastically supporting the upper foil portion, Wherein the upper foil portion is divided into a plurality of parts.

2. The thrust bearing according to claim 1, characterized in that: The lower foil portion includes a base foil portion including a first plate-like member that planarly supports a portion of the bearing surface of the upper foil portion.

3. The thrust bearing according to claim 2, characterized in that: The lower foil portion includes a first supporting foil portion, which is arranged below the base foil portion and comprises a plurality of first supporting members, a backing foil portion arranged below the first supporting foil portion and comprising a second plate-like member corresponding to the first plate-like member, and a second supporting foil portion, which is arranged below the backing foil portion and includes a plurality of second supporting members; The first plate-shaped member is supported by two first support members among the plurality of first support members; One of the two first supporting members is supported by a portion of the second plate-like member and two second supporting members of the plurality of second supporting members; as well as The other of the two first supporting members is supported by a portion different from the portion of the second plate-shaped member, one of the two second supporting members, and a second supporting member different from the two second supporting members.

4. The thrust bearing according to claim 3, characterized in that: The lower foil portion elastically supports the upper foil portion so that a supporting rigidity of each of the plurality of portions on an upstream side in a rotational direction of the rotating member is smaller than a supporting rigidity of each of the plurality of portions on a downstream side in the rotational direction.

5. The thrust bearing according to claim 4, characterized in that: The one of the two first support members is arranged on the upstream side of the other of the two first support members in the rotation direction; as well as A distance between the two second supporting members is greater than a distance between the one of the two second supporting members and the second supporting member different from the two second supporting members.

6. The thrust bearing according to claim 4, characterized in that: The thickness of the first plate-shaped member on the upstream side in the rotational direction is smaller than the thickness of the first plate-shaped member on the downstream side in the rotational direction.

7. The thrust bearing according to claim 4, characterized in that: The one of the two first support members is arranged on the upstream side of the other of the two first support members in the rotation direction; as well as The thickness of the one of the two first supporting members is smaller than the thickness of the other of the two first supporting members.

8. The thrust bearing according to claim 2, characterized in that: The first plate-like member of the bottom foil portion is arranged in a region surrounded by the first annular member; The bottom foil portion also includes the first annular member extending in the circumferential direction of the thrust bearing, and a first connecting member connecting the first annular member and the first plate-shaped member; A length from a first connection point to a second connection point along the shape of the first connection member is greater than a length of a straight line connecting the first connection point and the second connection point; The first connection point is a connection point between the first annular member and the first connection member; and The second connection point is a connection point between the first plate-shaped member and the first connection member.

9. The thrust bearing according to claim 3, characterized in that: The first supporting foil portion comprises a second annular member extending in a circumferential direction of the thrust bearing, the first supporting member being arranged in a region surrounded by the second annular member, and a second connecting member connecting the second annular member and the one first supporting member among the plurality of first supporting members; A length from a third connection point to a fourth connection point along the shape of the second connection member is greater than a length of a straight line connecting the third connection point and the fourth connection point; The third connection point is a connection point between the second annular member and the second connection member; and The fourth connection point is a connection point between the one first supporting member and the second connection member.

10. The thrust bearing according to claim 4, characterized in that: The portion of the second plate-shaped member and the two second support members define a two-end support beam structure, and the two-end support beam structure supports the one first support member of the two first support members; as well as The portion different from the portion of the second plate-shaped member, the one of the two second supporting members, and the second supporting member different from the two second supporting members define a two-end support beam structure that supports the other of the two first supporting members.

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