Sliding bearing and rotary machine

Abstract

To provide a sliding bearing capable of sufficiently exhibiting its own function without strictly managing a clearance.SOLUTION: The sliding bearing includes an intermediate bearing body. The intermediate bearing body is in close contact with one of the fixed-side bearing body and the rotation-side bearing body to form a first sliding surface between the intermediate bearing body and the other bearing body, and is in close contact with the other bearing body to form a second sliding surface between the intermediate bearing body and the one bearing body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sliding bearing and a rotating machine. [Background technology]

[0002] In recent years, the temperature of the liquid handled by pumps (handled liquid) has been getting lower (below freezing), while the temperature of the handled liquid has also been getting higher. There is a demand for pumps that can be used to transport handled liquids over such a wide temperature range (for example, 100°C). At the same time, price competition for pumps in the market is intensifying, and there is a demand for compact, inexpensive pumps. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 7-4927 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-294028 Summary of the Invention [Problem to be solved by the invention]

[0004] The pumps described above often employ sliding bearings to support their rotating shafts. A sliding bearing typically includes a rotating member and a fixed member. The sliding bearing supports the rotating shaft by utilizing a wedge effect, with a liquid interposed in the gap between these members, preventing the rotating member and the fixed member from coming into contact with each other. Slide bearings have excellent durability, and depending on the design, can also handle high-speed rotation that is difficult for ball bearings and other bearings to handle.

[0005] In order to reduce the cost of the pump and to facilitate maintenance of the sliding bearings, the fixed and rotating members may be made of different materials. In this case, if the fixed and rotating members have different linear expansion coefficients, there is a risk that at least one of the fixed and rotating members will undergo significant deformation due to temperature changes in the pumped fluid.

[0006] Therefore, when using a plain bearing, the size of the gap between the rotating and fixed components must be determined precisely, taking into account the linear expansion coefficient of the material. Managing this gap precisely is time-consuming and has a negative impact on the price of the pump.

[0007] The above-mentioned problems are not limited to pumps for transporting fluids having a wide temperature range. For example, such problems can also exist in rotary machines (e.g., canned motors, oil-sealed motors, etc.) that use plain bearings, which change shape due to temperature changes.

[0008] Therefore, an object of the present invention is to provide a sliding bearing and a rotating machine that can fully perform their functions without requiring strict control of the clearance. [Means for solving the problem]

[0009] In one aspect, there is provided a sliding bearing comprising a fixed-side bearing body, a rotating-side bearing body, and an intermediate bearing body disposed between the fixed-side bearing body and the rotating-side bearing body, wherein the intermediate bearing body comes into close contact with one of the fixed-side bearing body and the rotating-side bearing body upon cooling, forming a first sliding surface between the intermediate bearing body and the other bearing body, and when heated, the intermediate bearing body comes into close contact with the other bearing body, forming a second sliding surface between the one of the bearing bodies.

[0010] In one embodiment, the intermediate bearing body is made of resin, and at least one of the fixed-side bearing body and the rotating-side bearing body is made of a material harder than the intermediate bearing body. In one embodiment, the intermediate bearing body has dynamic pressure grooves formed in at least one of the first sliding surface and the second sliding surface. In one embodiment, the one bearing body has dynamic pressure grooves formed in an opposing surface that faces the second sliding surface.

[0011] In one embodiment, the other bearing body has dynamic pressure grooves formed in an opposing surface that faces the first sliding surface. In one aspect, the intermediate bearing body has a cylindrical portion and a flange portion connected to the cylindrical portion and limiting movement of the cylindrical portion in the axial direction.

[0012] In one aspect, a rotary machine is provided, comprising: a rotating body; and a sliding bearing that rotatably supports the rotating body, the sliding bearing comprising a fixed-side bearing body, a rotating-side bearing body, and an intermediate bearing body disposed between the fixed-side bearing body and the rotating-side bearing body, wherein the intermediate bearing body comes into close contact with one of the fixed-side bearing body and the rotating-side bearing body upon cooling, forming a first sliding surface between the intermediate bearing body and the other bearing body, and the intermediate bearing body comes into close contact with the other bearing body upon heating, forming a second sliding surface between the intermediate bearing body and the one bearing body.

[0013] In one embodiment, the intermediate bearing body is made of resin, and at least one of the fixed-side bearing body and the rotating-side bearing body is made of a material harder than the intermediate bearing body. In one embodiment, the intermediate bearing body has dynamic pressure grooves formed in at least one of the first sliding surface and the second sliding surface. In one embodiment, the one bearing body has dynamic pressure grooves formed in an opposing surface that faces the second sliding surface.

[0014] In one embodiment, the other bearing body has dynamic pressure grooves formed in an opposing surface that faces the first sliding surface. In one aspect, the intermediate bearing body has a cylindrical portion and a flange portion connected to the cylindrical portion and limiting movement of the cylindrical portion in the axial direction. In one aspect, the rotary machine includes a bearing supporter that supports the fixed-side bearing body. In one embodiment, the bearing supporter is made of a different material from the fixed-side bearing body. [Effects of the Invention]

[0015] The sliding bearing includes an intermediate bearing body having a first sliding surface and a second sliding surface. Therefore, even if the shape of the intermediate bearing body changes due to temperature changes, the sliding bearing can fully perform its function without strict control of the gap. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 illustrates an embodiment of a motor pump. [Figure 2] FIG. 1 is an enlarged view showing an embodiment of a sliding bearing. [Figure 3] 10A and 10B are diagrams showing the state of an intermediate bearing body at high temperatures (including normal temperatures). [Figure 4] FIG. 10 is a diagram showing the state of the intermediate bearing body at low temperatures. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, identical or corresponding components are designated by the same reference numerals, and duplicated descriptions will be omitted. In the multiple embodiments described below, the configuration of an embodiment that is not particularly described is the same as that of other embodiments, and therefore duplicated descriptions will be omitted.

[0018] FIG. 1 is a diagram showing one embodiment of a motor pump. In the embodiment shown in FIG. 1, the motor pump MP is a rotary machine (more specifically, a canned motor pump) equipped with a permanent magnet motor. In the following, in this embodiment, a canned motor pump will be described as an example of a rotary machine, but the rotary machine is not limited to a canned motor pump. Other examples of rotary machines include oil-sealed motors, turbines, and blowers.

[0019] The motor pump MP comprises an impeller 1 as a rotating body, a sliding bearing 50 that supports the impeller 1 so that it can rotate freely, a motor 10 that rotates the impeller 1, and a motor pump casing MPC that houses the impeller 1, the motor 10, and the sliding bearing 50.

[0020] The motor pump casing MPC includes a suction casing SC and a discharge casing DC arranged on either side of the impeller 1, and a motor frame MF arranged between the suction casing SC and the discharge casing DC.

[0021] The suction casing SC has a suction port SP formed in its center. Similarly, the discharge casing DC has a discharge port DP formed in its center. The suction port SP and the discharge port DP are aligned in a straight line along the overall axis AX of the motor pump MP. Liquid (handled liquid) sucked into the internal space of the motor pump MP through the suction port SP passes through the impeller 1 and is transported to the outside through the discharge port DP.

[0022] 1, the plain bearing 50 includes a rotating-side bearing body 50A fixed to the impeller 1, a fixed-side bearing body 50B facing the rotating-side bearing body 50A, and an intermediate bearing body 50C arranged between the fixed-side bearing body 50B and the rotating-side bearing body 50A. The specific structure of the plain bearing 50 will be described later.

[0023] The motor 10 has a rotor 11 embedded in a rotating-side bearing body 50A and a stator 12 arranged radially outward of the rotor 11. The stator 12 has a stator core 12a and a plurality of coils 12b wound around the stator core 12a. When power is supplied to the stator 12, the stator 12 generates a rotating magnetic field. The rotor 11 rotates the impeller 1 via the rotating-side bearing body 50A due to the action of the rotating magnetic field from the stator 12.

[0024] The motor pump casing MPC includes a stator can CA arranged radially inside the motor frame MF. The motor frame MF and the stator can CA are arranged concentrically with each other. The stator 12 is housed in a cylindrical, liquid-tight space formed between the motor frame MF and the stator can CA.

[0025] When the impeller 1 rotates, liquid is introduced into the motor pump casing MPC through the suction port SP. A portion of the liquid pressurized by the rotation of the impeller 1 passes through the gap between the stator can CA and the rotating-side bearing body 50A and is introduced into the plain bearing 50 located on the upstream side of the impeller 1. The remaining liquid is introduced into the gap between the partition plate 20 located on the downstream side of the impeller 1 and the discharge casing DC. The liquid is then transported to the outside through the discharge port DP.

[0026] In this embodiment, the motor pump MP is configured to transfer a liquid (handled liquid) having a wide temperature range (for example, 100°C), from low-temperature liquid to high-temperature liquid. However, when transferring such a liquid, if the plain bearing 50 comes into contact with the liquid, there is a risk that the shape of the plain bearing 50 will change significantly due to thermal expansion or thermal contraction.

[0027] Generally, the size of the gap in the sliding bearing 50 must be determined precisely, taking into consideration such shape changes (more specifically, the linear expansion coefficient of the material), but such strict control of the gap is time-consuming. If the size of the gap is not appropriate, the sliding bearing 50 will not be able to fully perform its functions.

[0028] Therefore, in this embodiment, the plain bearing 50 has a structure that allows it to fully perform its function without strict control of the gap. The structure of the plain bearing 50 will be described below with reference to the drawings.

[0029] 2 is an enlarged view showing one embodiment of a sliding bearing. The rotating-side bearing body 50A has a cylindrical shape that protrudes from the impeller 1 toward the suction casing SC. In this embodiment, the rotating-side bearing body 50A is configured as a separate member from the impeller 1, but in another embodiment, the rotating-side bearing body 50A may be a member molded integrally with the impeller 1.

[0030] The fixed-side bearing body 50B is a cylindrical bearing body with an L-shaped cross section. The fixed-side bearing body 50B is arranged so that at least a portion of it is inserted into the rotating-side bearing body 50A. In other words, at least a portion of the fixed-side bearing body 50B is arranged radially inward of the rotating-side bearing body 50A.

[0031] The intermediate bearing body 50C is a cylindrical bearing body with an L-shaped cross section, similar to the fixed-side bearing body 50B. The intermediate bearing body 50C is attached to the rotating-side bearing body 50A by cold press-fitting or other means, and at room temperature, a gap is formed between the intermediate bearing body 50C and the fixed-side bearing body 50B.

[0032] In one embodiment, the intermediate bearing body 50C may be attached to the fixed-side bearing body 50B by means of cold press-fitting or the like. In this case, at room temperature, a gap is formed between the intermediate bearing body 50C and the rotating-side bearing body 50A.

[0033] The motor pump MP is equipped with a bearing supporter 55 that supports the fixed-side bearing body 50B (see FIG. 1). Similar to the fixed-side bearing body 50B, the bearing supporter 55 has an L-shaped cross section and is fixed to the suction casing SC.

[0034] The bearing supporter 55 is disposed concentrically with the suction casing SC (and the discharge casing DC). Therefore, the liquid introduced into the suction port SP of the suction casing SC passes through a flow path in the bearing supporter 55 and is then introduced into the impeller 1.

[0035] The fixed-side bearing body 50B has a cylindrical portion 50B-1 extending in the direction of the axis AX and a flange portion 50B-2 connected to the cylindrical portion 50B-1. The cylindrical portion 50B-1 and the flange portion 50B-2 extend perpendicular to each other.

[0036] The fixed-side bearing body 50B is inserted into the bearing supporter 55 by means of a clearance fit or the like. A flange portion 50B-2 of the fixed-side bearing body 50B has a notch 56 formed at its end. The bearing supporter 55 has an insertion hole 55a for inserting a locking pin 60. In one embodiment, the flange portion 50B-2 may have a through-hole for inserting the locking pin 60 instead of the notch 56.

[0037] The anti-rotation pin 60 is a pin that prevents the fixed-side bearing body 50B from rotating relative to the bearing supporter 55. By inserting the anti-rotation pin 60 into the notch 56 and the insertion hole 55a, the anti-rotation pin 60 prevents the fixed-side bearing body 50B from rotating relative to the bearing supporter 55. On the other hand, the fixed-side bearing body 50B inserted into the bearing supporter 55 is configured to move in the direction of the axis AX due to the clearance fit.

[0038] The bearing supporter 55 is made of a different material from the fixed-side bearing body 50B. More specifically, the bearing supporter 55 is made of a material that has a higher strength than the fixed-side bearing body 50B. For example, the fixed-side bearing body 50B is made of a hard material such as ceramics, and the bearing supporter 55 is made of a metal material such as stainless steel.

[0039] While ceramics has excellent wear resistance, it is relatively vulnerable to impact and expensive. Therefore, if the bearing supporter 55 were made of the same material as the fixed-side bearing body 50B, there is a risk that the bearing supporter 55 would be damaged or that the overall cost of the motor pump MP would increase.

[0040] In this embodiment, the bearing supporter 55 made of stainless steel has relatively high strength and is inexpensive. Therefore, the bearing supporter 55 can absorb impacts acting on the fixed-side bearing body 50B while preventing damage to the bearing supporter 55. Furthermore, the motor pump MP equipped with the bearing supporter 55 can reduce its overall cost.

[0041] Unlike the fixed-side bearing body 50B, the intermediate bearing body 50C is made of a soft material such as resin. The rotating-side bearing body 50A is made of a harder material (for example, stainless steel) than the intermediate bearing body 50C.

[0042] In this embodiment, both the rotating side bearing body 50A and the fixed side bearing body 50B are made of a material that is harder than the intermediate bearing body 50C, but at least one of the fixed side bearing body 50B and the rotating side bearing body 50A may be made of a material that is harder than the intermediate bearing body 50C.

[0043] Generally, resin has good productivity and is inexpensive compared to hard materials such as metals, ceramics, and superhard materials. Therefore, by making the intermediate bearing body 50C out of resin, the entire sliding bearing 50 can be made inexpensive and lightweight. Furthermore, even if the intermediate bearing body 50C is damaged by wear, it can be easily replaced.

[0044] On the other hand, resin has a large coefficient of linear expansion, and is subject to significant shape changes due to temperature changes. Additionally, the resin's characteristic water absorption causes swelling and dimensional changes. In this embodiment, the intermediate bearing body 50C, made of resin, is configured to closely adhere to the rotating-side bearing body 50A or the fixed-side bearing body 50B due to its shape change.

[0045] The intermediate bearing body 50C has a cylindrical portion 50C-1 extending in the direction of the axis AX and a flange portion 50C-2 connected to the cylindrical portion 50C-1. The cylindrical portion 50C-1 and the flange portion 50C-2 extend perpendicular to each other. In this embodiment, the fixed-side bearing body 50B and the intermediate bearing body 50C have similar shapes. More specifically, both the fixed-side bearing body 50B and the intermediate bearing body 50C have a cylindrical portion and a flange portion, but have different sizes.

[0046] 3 is a diagram showing the state of the intermediate bearing body at high temperatures (including room temperature). When a high-temperature liquid is introduced into the sliding bearing 50, the intermediate bearing body 50C is heated by the high-temperature liquid. When the intermediate bearing body 50C is heated by the high-temperature liquid, thermal expansion causes the intermediate bearing body 50C to come into close contact with the rotating-side bearing body 50A, forming a sliding surface SS1 between it and the fixed-side bearing body 50B.

[0047] When the motor pump MP is operated and liquid is introduced into the gap between the intermediate bearing body 50C, which rotates together with the rotating side bearing body 50A, and the fixed side bearing body 50B, the wedge effect causes the intermediate bearing body 50C (and the rotating side bearing body 50A) to be supported by the fixed side bearing body 50B without contact.

[0048] To more actively exert the wedge effect, the intermediate bearing body 50C may have a plurality of dynamic pressure grooves GR formed in the sliding surface SS1 (see FIG. 2). The dynamic pressure grooves GR are annular grooves extending along the rotation direction of the impeller 1. In the embodiment shown in FIG. 2, the plurality of dynamic pressure grooves GR are formed over the entire sliding surface SS1 of the intermediate bearing body 50C.

[0049] 2, the dynamic pressure grooves GR are formed in both the cylindrical portion 50C-1 and the flange portion 50C-2. In one embodiment, the dynamic pressure grooves GR may be formed in either the cylindrical portion 50C-1 or the flange portion 50C-2.

[0050] In this embodiment, the intermediate bearing body 50C has multiple dynamic pressure grooves GR, but in one embodiment, the fixed side bearing body 50B may have multiple dynamic pressure grooves formed on the opposing surface OS1 that faces the sliding surface SS1 of the intermediate bearing body 50C (not shown).

[0051] 4 is a diagram showing the state of the intermediate bearing body at low temperatures. When a low-temperature liquid is introduced into the plain bearing 50, the intermediate bearing body 50C is cooled by the low-temperature liquid. When the intermediate bearing body 50C is cooled by the low-temperature liquid, the intermediate bearing body 50C comes into close contact with the fixed-side bearing body 50B due to thermal contraction, forming a sliding surface SS2 between the intermediate bearing body 50C and the rotating-side bearing body 50A. In this way, the intermediate bearing body 50C switches from being a rotating-side bearing body to being a fixed-side bearing body.

[0052] When a liquid is introduced into the gap between the intermediate bearing body 50C supported by the fixed side bearing body 50B and the rotating side bearing body 50A, the wedge effect causes the rotating side bearing body 50A to be supported by the intermediate bearing body 50C (and the fixed side bearing body 50B) without coming into contact with the intermediate bearing body 50C.

[0053] In this embodiment as well, the intermediate bearing body 50C may have a plurality of dynamic pressure grooves GR formed in the sliding surface SS2 (see FIG. 2). The plurality of dynamic pressure grooves GR may be formed in both the cylindrical portion 50C-1 and the flange portion 50C-2, or may be formed in either the cylindrical portion 50C-1 or the flange portion 50C-2.

[0054] Although not shown, the rotating-side bearing body 50A may have a plurality of dynamic pressure grooves formed on an opposing surface OS2 that faces the sliding surface SS2 of the intermediate bearing body 50C.

[0055] The dynamic pressure grooves GR formed in the intermediate bearing body 50C do not necessarily have to be formed on either the sliding surface SS1 or the sliding surface SS2, and the intermediate bearing body 50C may have dynamic pressure grooves GR formed on at least one of the sliding surface SS1 and the sliding surface SS2.

[0056] According to this embodiment, even if the shape of the intermediate bearing body 50C changes due to a change in the temperature of the liquid, the intermediate bearing body 50C reliably forms a gap of an appropriate size (i.e., the first sliding surface SS1 and the second sliding surface SS2) between the rotating side bearing body 50A or the fixed side bearing body 50B.

[0057] With this configuration, there is no need to strictly determine the size of the gap in the plain bearing 50, and gap management is not required. As a result, the plain bearing 50 can fully perform its function without strict gap management. Furthermore, the plain bearing 50 has a simple structure that includes an intermediate bearing body 50C with a high linear expansion coefficient. Therefore, the motor pump MP is inexpensive and can be used with fluids over a wide temperature range.

[0058] The intermediate bearing body 50C may become detached from the rotating-side bearing body 50A and the fixed-side bearing body 50B due to thermal expansion or contraction, and may temporarily not be in close contact with either the rotating-side bearing body 50A or the fixed-side bearing body 50B.

[0059] In this embodiment, the flange portion 50C-2 of the intermediate bearing body 50C is disposed between the rotating-side bearing body 50A and the fixed-side bearing body 50B (more specifically, the flange portion 50B-2) in the direction of the axis AX.

[0060] Therefore, even if the intermediate bearing body 50C were to come off the rotating-side bearing body 50A and the fixed-side bearing body 50B, the flange portion 50C-2 restricts the movement of the cylindrical portion 50C-1 in the direction of the axis AX. As a result, the entire intermediate bearing body 50C can be prevented from coming off the rotating-side bearing body 50A and the fixed-side bearing body 50B.

[0061] In the above-described embodiment, a sliding bearing 50 is described that includes a fixed-side bearing body 50B as a stationary member that does not rotate with the impeller 1, and a rotating-side bearing body 50A as a rotating member that rotates with the impeller 1, but the arrangement of the rotating-side bearing body 50A and the fixed-side bearing body 50B is not limited to the above-described embodiment.

[0062] In this embodiment, the plain bearing 50 includes a rotating-side bearing body 50A arranged radially outward from the fixed-side bearing body 50B. In one embodiment, the plain bearing 50 may include a rotating-side bearing body 50A arranged radially inward from the fixed-side bearing body 50B.

[0063] In this case, when the intermediate bearing body 50C thermally contracts, the intermediate bearing body 50C comes into close contact with the rotating-side bearing body 50A, forming a sliding surface between it and the fixed-side bearing body 50B. Conversely, when the intermediate bearing body 50C thermally expands, the intermediate bearing body 50C comes into close contact with the fixed-side bearing body 50B, forming a sliding surface between it and the rotating-side bearing body 50A.

[0064] In the above-described embodiment, a motor pump MP to which the sliding bearing 50 is applied has been described, but the sliding bearing 50 is not necessarily applicable only to motor pumps MP, and can also be applied to rotating machines other than motor pumps MP (e.g., canned motors, oil-sealed motors).

[0065] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims. [Explanation of symbols]

[0066] 1 impeller 10 Motor 11 Rotor 12 Stator 12a stator core 12b coil 20 Divider 50 Plain bearing 50A Rotating side bearing body 50B Fixed side bearing body 50B-1 Cylindrical part 50B-2 flange 50C intermediate bearing body 50C-1 Cylindrical part 50C-2 flange 55 Bearing supporter 55a Insertion hole 60 Anti-rotation pin MP motor pump MPC motor pump casing SC suction casing SP intake port DC discharge casing DP outlet MF motor frame AX axis CA Stator Can SS1 Sliding surface SS2 sliding surface GR hydrodynamic groove OS1 Opposite surface OS2 Opposite surface

Claims

1. A plain bearing, a fixed-side bearing body and a rotating-side bearing body; an intermediate bearing body disposed between the fixed-side bearing body and the rotating-side bearing body, The intermediate bearing body is the intermediate bearing body is cooled to come into close contact with one of the fixed-side bearing body and the rotating-side bearing body, forming a first sliding surface between the other bearing body and the intermediate bearing body; a sliding bearing in which, when the intermediate bearing body is heated, it comes into close contact with the other bearing body, forming a second sliding surface between the intermediate bearing body and the one bearing body.

2. the intermediate bearing body is made of resin, 2. The sliding bearing according to claim 1, wherein at least one of the fixed-side bearing body and the rotating-side bearing body is made of a material that is harder than a material of the intermediate bearing body.

3. 2. The sliding bearing according to claim 1, wherein the intermediate bearing body has hydrodynamic grooves formed in at least one of the first sliding surface and the second sliding surface.

4. 2. The sliding bearing according to claim 1, wherein the one bearing body has dynamic pressure grooves formed in an opposing surface that faces the second sliding surface.

5. 2. The sliding bearing according to claim 1, wherein the other bearing body has dynamic pressure grooves formed in an opposing surface that faces the first sliding surface.

6. The intermediate bearing body is A cylindrical portion; 2. The sliding bearing according to claim 1, further comprising: a flange portion connected to said cylindrical portion and limiting movement of said cylindrical portion in the axial direction.

7. A rotating machine, A rotating body; a slide bearing that rotatably supports the rotating body, The sliding bearing is a fixed-side bearing body and a rotating-side bearing body; an intermediate bearing body disposed between the fixed-side bearing body and the rotating-side bearing body, The intermediate bearing body is the intermediate bearing body is cooled to come into close contact with one of the fixed-side bearing body and the rotating-side bearing body, forming a first sliding surface between the other bearing body and the intermediate bearing body; a rotary machine, wherein the intermediate bearing body is heated to come into close contact with the other bearing body, forming a second sliding surface between the intermediate bearing body and the one bearing body.

8. the intermediate bearing body is made of resin, The rotary machine according to claim 7 , wherein at least one of the fixed-side bearing body and the rotating-side bearing body is made of a material harder than that of the intermediate bearing body.

9. The rotary machine according to claim 7 , wherein the intermediate bearing body has hydrodynamic grooves formed in at least one of the first sliding surface and the second sliding surface.

10. The rotary machine according to claim 7 , wherein the one bearing body has dynamic pressure grooves formed in an opposing surface facing the second sliding surface.

11. The rotary machine according to claim 7 , wherein the other bearing body has dynamic pressure grooves formed in an opposing surface facing the first sliding surface.

12. The intermediate bearing body is A cylindrical portion; The rotary machine according to claim 7 , further comprising: a flange portion connected to the cylindrical portion and limiting movement of the cylindrical portion in the axial direction.

13. The rotary machine according to claim 7 , further comprising a bearing supporter that supports the fixed-side bearing body.

14. The rotary machine according to claim 13 , wherein the bearing supporter is made of a material different from that of the fixed-side bearing body.

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