JP6941548B2 - bearing - Google Patents

Description

The present invention relates to bearings.

Patent Document 1 discloses a submersible bearing used in a vertical shaft pump. This underwater bearing includes three sliding bodies arranged in the axial direction of the rotating shaft, and these sliding bodies are connected by a coupling member having thermal conductivity.

Japanese Unexamined Patent Publication No. 2015-20234

In the underwater bearing of Patent Document 1, the heat of the sliding body is merely dissipated to the casing via the coupling member, and the sliding body cannot be effectively cooled.

An object of the present invention is to provide a bearing capable of effectively cooling a sliding body.

One aspect of the present invention includes a sliding body arranged on the outer periphery of the rotating shaft and a back shell arranged on the outer periphery of the sliding body and holding the sliding body, and has an inner peripheral surface and an outer peripheral surface of the back shell. between the through-hole penetrating in the axial direction of the rotary shaft is provided, et al is, in the inner circumferential surface of said back shell, a groove recessed in a direction away from the sliding body is provided, the bearing offer.

According to this bearing, when the sliding body generates heat due to the rotation of the rotating shaft, air flows (natural convection) in the through hole of the back shell due to the temperature difference between the sliding body and the surrounding air. In addition, the air supply mechanism can force air to flow through the through hole of the back shell. As a result, the back shell can be efficiently cooled by the heat exchange action, and the sliding body can be effectively cooled through the back shell, so that the seizure of the rotating shaft on the sliding body due to heat generation can be suppressed. Further, since the cooling through hole is provided in the back shell instead of the sliding body, the holding of the rotating shaft by the sliding body is not affected. In addition, the inner peripheral surface of the back shell is provided with a groove that is recessed in a direction away from the sliding body, and air flows through the gap formed between the sliding body and the back shell by this groove. Cooling efficiency can be improved.

A casing having a ventilation hole communicating with the through hole is arranged on the outer periphery of the back shell. According to this aspect, the air outside the casing can be reliably flowed through the through hole of the back shell, and the sliding body can be effectively cooled. Further, when the air supply mechanism is provided, the air supply pipe can be connected to the ventilation hole.

Another aspect of the present invention includes a sliding body arranged on the outer periphery of the rotating shaft and a back shell arranged on the outer periphery of the sliding body and holding the sliding body, and the inner peripheral surface and the outer peripheral surface of the back shell. A bearing is provided in which a through hole penetrating in the axial direction of the rotating shaft is provided between the surfaces, and a casing having a ventilation hole communicating with the through hole is arranged on the outer periphery of the back shell. ..

The back shell has an inner ring member arranged on the outer periphery of the sliding body and an outer ring member arranged on the outer periphery of the inner ring member, and has an outer surface of the inner ring member and an inner surface of the outer ring member. A groove forming the through hole is provided in at least one of them. According to this aspect, a through hole having a predetermined shape can be reliably formed in the back shell.

The grooves forming the through hole are formed in a spiral shape. According to this aspect, since the distance through which the air flows can be lengthened, the heat exchange time can be secured and the cooling efficiency of the bearing can be improved. For example, the through hole is formed by providing a screw protrusion on one side and a screw groove on the other side of the inner ring member and the outer ring member so that the groove depth is larger than the protrusion height. In this case, the screw protrusion and the screw groove can also be used for assembling the inner ring member and the outer ring member. Further, it is preferable to form the screw protrusion and the screw groove so that the direction in which the inner ring member is tightened with respect to the outer ring member is the same as the direction in which the rotation shaft rotates.

The inner ring member and the outer ring member are fixed by fixing pins. According to this aspect, it is possible to prevent the inner ring member and the outer ring member from loosening due to the rotation of the rotating shaft and being decomposed.

A vibration-proof member having a plurality of ridges abutting on the outer peripheral surface of the back shell is arranged on the outer circumference of the back shell, and the ridges extend along the axial direction of the rotation axis and rotate around the circumference. It is provided at intervals in the direction. According to this aspect, since air can be flowed to the outer peripheral surface side of the back shell, the back shell can be reliably cooled, and the sliding body can be effectively cooled via the back shell.

The anti-vibration member has two or more bump foil bearings made of a metal plate having a uniform thickness, and the two or more bump foil bearings are arranged in the axial direction of the rotating shaft and are adjacent to the bump foil bearings. The formed ridges are arranged at different positions in the circumferential direction of the rotation axis. According to this aspect, since air can flow in the vibration isolator member, the heat resistant temperature of the vibration isolator member can be improved, and a damping function against vibration of the rotating shaft can be provided. In addition, the cooling efficiency of individual bump foil bearings can be improved.

In the bearing of the present invention, air flows through the through hole formed in the back shell, so that the sliding body can be effectively cooled through the back shell. Therefore, seizure of the rotating shaft on the sliding body due to heat generation can be suppressed.

The cross-sectional view which shows the vertical shaft pump using the bearing which concerns on 1st Embodiment of this invention. The vertical sectional view of the bearing of 1st Embodiment. FIG. 2 is a cross-sectional view of the bearing of FIG. FIG. 2 is an exploded perspective sectional view of the bearing of FIG. The perspective view which shows the inner peripheral surface of a back shell. The vertical sectional view of the bearing of the 2nd Embodiment. The vertical sectional view of the bearing of the 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)
FIG. 1 shows a bearing 40 according to the first embodiment of the present invention applied to a leading standby type vertical shaft pump (hereinafter, simply referred to as a vertical shaft pump) 10. The bearing 40 is provided with a cooling structure by air cooling to suppress seizure of the rotating shaft 21.

(Overview of vertical pump)
The vertical shaft pump 10 drains rainwater or the like that has flowed into the water absorption tank 1 to the downstream side, and includes a pump casing 12, a rotating shaft 21, an impeller 24, and a drive unit 26.

The pump casing 12 is fixed to the installation floor 2 that covers the water absorption tank 1, and includes a pumping pipe 13 arranged in the water absorption tank 1 and a discharge pipe 18 arranged on the installation floor 2. The pumping pipe 13 includes a straight pipe 14, a vane casing 15, and a bell mouth 17, and is connected from the upper side to the lower side in this order. The discharge pipe 18 includes a discharge elbow 19 whose central axis is curved by 90 degrees, and is connected to the upper end of the straight pipe 14. A water pipe (not shown) for draining water to the downstream side is connected to the outlet of the discharge elbow 19.

The rotating shaft 21 penetrates the discharge elbow 19 and is rotatably arranged along the axis of the pumping pipe 13. The upper end of the rotating shaft 21 projects outward from the discharge elbow 19. The portion of the discharge elbow 19 through which the rotating shaft 21 penetrates is watertightly sealed by a shaft sealing device.

The impeller 24 is fixed to the lower end of the rotating shaft 21 located in the vane casing 15. A bearing casing 16 is fixed in the vane casing 15, and an impeller 24 is arranged below the bearing casing 16.

The drive unit 26 includes an electric motor connected to the upper end of the rotating shaft 21. A diesel engine, which is one of the internal combustion engines, may be used for the drive unit 26 instead of the electric motor. When the rotary shaft 21 is rotated by the drive of the drive unit 26, the impeller 24 is rotated integrally with the rotary shaft 21, and the water in the water absorption tank 1 is discharged to the downstream side through the inside of the pump casing 12. ..

The leading standby type vertical shaft pump 10 is driven in advance by the control unit 35 before water is stored in the water absorption tank 1. The vertical shaft pump 10 has a drainage operation for discharging water to the downstream side depending on the water level in the water absorption tank 1, a gas-water mixing operation for holding pumped water in the pumping pipe 13 without draining, and no pumping in the pumping pipe 13. Switch to aerial operation. In any state, one or more bearings 40 as underwater bearings are arranged in order to smoothly rotate the rotating shaft 21. In the present embodiment, a total of three bearings 40 are arranged in the vane casing 15 and the straight pipe 14.

The bearing 40 rotatably supports the rotating shaft 21. During the drainage operation and the air-water mixing operation, the bearing 40 is cooled by the water filled in the pumping pipe 13 and therefore does not generate excessive heat. However, in the aerial operation in which there is no water in the pumping pipe 13, the bearing 40 is not cooled by the water, so that heat is generated by the sliding contact of the rotating shaft 21. In order to prevent seizure of the rotating shaft 21 due to excessive heat generation of the bearing 40, the bearing 40 of the present embodiment is provided with a cooling structure by air cooling.

(Overview of bearings)
As shown in FIGS. 2 to 4, the bearing 40 has a cylindrical shape and includes two sets of sliding body units arranged at intervals in the axial direction of the rotating shaft 21. The sliding body unit includes a sliding body 42, a back shell 46, and a vibration isolator member 61 in this order from the rotating shaft 21 to the outside in the radial direction. These sliding body units are arranged in the cover case (casing) 66 so that the back shell 46 is turned upside down. In the present embodiment, the back shell 46 is provided with a through hole 47 through which air can flow, and is configured so that the sliding body 42 can be effectively cooled via the back shell 46.

The sliding body 42 is made of ceramic or a resin having a low thermal conductivity, and is provided with a shaft hole 43 through which the rotating shaft 21 (sleeve 22) is inserted at the center. Although the sliding body 42 is formed in a cylindrical shape surrounding the rotating shaft 21, it may be formed in a plurality of fan shapes divided in the circumferential direction.

The back shell 46 has a cylindrical shape and is made of a material having good thermal conductivity such as stainless steel or a copper alloy. The back shell 46 is arranged outside the outer peripheral surface 44 of the sliding body 42, and holds (fixes) the sliding body 42. The back shell 46 of the present embodiment is composed of an inner ring member 48 and an outer ring member 54, and an air-cooling through hole 47 penetrating in the axial direction of the rotating shaft 21 is formed in a portion facing the inner ring member 48. There is.

The inner ring member 48 includes an inner peripheral surface 49 having substantially the same diameter as the outer peripheral surface 44 of the sliding body 42. The inner ring member 48 and the sliding body 42 are connected by shrink fitting. At one end of the inner ring member 48 in the axial direction, a protruding portion 51 that projects inward in the radial direction and holds one end of the sliding body 42 in the axial direction is provided.

The outer ring member 54 includes an inner peripheral surface 55 having substantially the same diameter as the outer peripheral surface 50 of the inner ring member 48. At one end of the outer ring member 54 in the axial direction, a protruding portion 57 that projects outward in the radial direction and holds one end of the vibration isolator 61 in the axial direction is provided.

The outer peripheral surface 50 of the inner ring member 48 is provided with a spiral thread groove 52 that is recessed inward in the radial direction of the inner ring member 48. The inner peripheral surface 55 of the outer ring member 54 is provided with a spiral screw protrusion 58 that projects inward in the radial direction of the outer ring member 54. By screwing the screw protrusion 58 into the screw groove 52, the inner ring member 48 and the outer ring member 54 are assembled. The direction in which the screw protrusion 58 is tightened with respect to the screw groove 52 is set to be the same as the direction in which the rotating shaft 21 rotates, and the rotation of the rotating shaft 21 loosens the inner ring member 48 and the outer ring member 54. It is preferable to prevent decomposition. The inner ring member 48 may be provided with a screw protrusion 58, and the outer ring member 54 may be provided with a screw groove 52.

The through hole 47 is composed of a screw groove 52 formed in the inner ring member 48. Specifically, the screw groove 52 is formed in a spiral shape that penetrates (continuously) from one end to the other end of the inner ring member 48. The groove depth of the screw groove 52 is formed to be larger than the protrusion height of the screw protrusion 58 of the outer ring member 54. These dimensional differences are set to a width that can secure a passage area through which air can naturally convection between the bottom of the screw groove 52 and the tip of the screw protrusion 58. As a result, the back shell 46 is formed with a spiral through hole 47 that communicates from one end to the other end in the axial direction. The screw protrusion 58 is provided on one end side of the outer ring member 54 and is formed in a spiral shape having a smaller number of turns than the screw groove 52, but is continuous from one end to the other end of the outer ring member 54. It may be formed.

The inner ring member 48 and the outer ring member 54 are further fixed by the fixing pin 59. The fixing pin 59 is formed of a hexagonal screw and is fastened radially inward from the outside of the outer ring member 54. The fixing pin 59 is arranged at a position where the screw groove 52 is not blocked.

Referring to FIG. 5, the inner peripheral surface 49 of the inner ring member 48 is provided with a concave groove 53 that is recessed in a direction away from the outer peripheral surface 44 of the sliding body 42. The groove 53 forms a gap for ventilation between the groove 53 and the sliding body 42, and is formed by knurling. The concave grooves 53 of the present embodiment are formed in a grid pattern and communicate with the inner ring member 48 from one end to the other end in the axial direction.

As shown in FIGS. 2 to 4, the vibration isolator 61 is composed of two or more (four in this embodiment) bump foil bearings 62 arranged on the outer periphery of the back shell 46. The bump foil bearing 62 is generally annular and is formed of a metal plate having a uniform thickness. The bump foil bearing 62 is formed with a plurality of ridges 64 that project inward in the radial direction from the outer peripheral portion 63 in a semicircular cross section and abut on the outer peripheral surface 56 of the back shell 46. The ridges 64 extend along the axial direction of the rotating shaft 21 and are provided at intervals in the circumferential direction.

The two or more bump foil bearings 62 are arranged in the axial direction of the rotating shaft 21 so that their respective centers are located on the same axis. As most clearly shown in FIG. 3, the ridges 64 of the adjacent bump foil bearings 62 are arranged at different positions in the circumferential direction of the rotating shaft 21. Specifically, the ridges 64 of the lower bump foil bearing 62 are arranged so as to be located between the adjacent ridges 64 of the upper bump foil bearing 62.

The cover case 66 arranges two sets of sliding body units side by side in the axial direction of the rotating shaft 21. The cover case 66 includes a cylindrical outer peripheral wall 67 that covers the outer peripheral portion of the vibration isolator member 61. End walls 68 protruding inward in the radial direction are provided at one end and the other end of the outer peripheral wall 67 in the axial direction of the rotating shaft 21, respectively. The outer peripheral wall 67 and the end wall 68 are each provided with a ventilation hole 69 communicating with the through hole 47. A plurality of ventilation holes 69 are provided at intervals determined in the circumferential direction.

As shown in FIG. 3, the cover case 66 and the back shell 46 (outer ring member 54) are fixed by a fixing pin 70. The fixing pin 70 is formed of a hexagonal screw and is fastened radially inward from the outside of the cover case 66. The anti-vibration member 61 is arranged inside the cover case 66, the back shell 46 is arranged inside the anti-vibration member 61, and the back shell 46 and the cover case 66 are fixed by the fixing pin 70. As a result, the anti-vibration member 61 is held between the cover case 66 and the back shell 46.

As shown in FIG. 2, in the bearing 40 configured in this way, a through hole 47 formed by the screw groove 52 is formed in the back shell 46. A gap through which air can flow is formed between the back shell 46 and the sliding body 42 by a concave groove 53 formed in the back shell 46. A gap through which air can flow is formed between the back shell 46 and the anti-vibration member 61 by the ridges 64 formed on the anti-vibration member 61. Since the anti-vibration member 61 is composed of a bump foil bearing 62 made of a metal plate, air can flow inside.

During the aerial operation of the vertical shaft pump 10, the rotation of the rotating shaft 21 causes the inner peripheral surface of the sliding body 42 to come into sliding contact with the sleeve 22 fixed to the rotating shaft 21, and the sliding body 42 generates heat. Therefore, the temperature inside the cover case 66 is higher than the temperature outside. The heat of the sliding body 42 is also conducted to the back shell 46 and the bump foil bearing 62.

(Cooling of sliding body by natural convection)
When the sliding body 42 generates heat, the air outside the cover case 66 passes through the ventilation holes 69 and the gap between the end wall 68 and the sleeve 22 due to the temperature difference between the air inside and outside the cover case 66, and goes from bottom to top. Flow (natural convection). At this time, the air is introduced into the through hole 47 of the back shell 46, the gap between the sliding body 42 and the sleeve 22, the gap between the back shell 46 and the sliding body 42, and the gap between the back shell 46 and the vibration isolator 61. And, it passes through the gap of the anti-vibration member 61 and adsorbs the heat of each component of the lower sliding body unit (heat exchange action). Of the air that has passed through the lower sliding body unit, a part of the air flows out of the cover case 66 through the ventilation holes 69 of the outer peripheral wall 67, and the rest passes through the upper sliding body unit, and each component of the upper sliding body unit. Adsorbs the heat of.

Specifically, the sliding body 42 is cooled by air flowing through the gap between the sliding body 42 and the sleeve 22 and the gap between the back shell 46 and the sliding body 42. The back shell 46 is cooled by the air flowing through the through hole 47 of the back shell 46, the gap between the back shell 46 and the sliding body 42, and the gap between the back shell 46 and the vibration isolator 61. The anti-vibration member 61 is cooled by the air flowing through the air gap between the back shell 46 and the anti-vibration member 61 and the air gap between the anti-vibration member 61. The cover case 66 is cooled by the air flowing through the voids of the vibration isolator 61 and the air outside the cover case 66.

As described above, in the bearing 40 of the present embodiment, the sliding body 42, the back shell 46, and the vibration isolator member 61 can be effectively cooled by the heat exchange action by natural convection. Further, the sliding body 42 having the highest temperature rise is also cooled by heat exchange with the back shell 46. Therefore, even if the sliding body 42 cannot be sufficiently cooled by heat exchange with air, the sliding body 42 can be effectively cooled via the back shell 46. As a result, seizure of the rotating shaft 21 due to excessive heat generation of the sliding body 42 can be suppressed.

(Cooling of sliding body by air supply)
The bearing 40 can be forcibly cooled by providing the air supply mechanism 28 for supplying air to the vertical shaft pump 10 and connecting the air supply mechanism 28 to the ventilation hole 69 of the outer peripheral wall 67 of the cover case 66.

As shown in FIG. 1, as the air supply mechanism 28, for example, a monitoring device for measuring the gap between the bearing 40 and the rotating shaft 21 can be used. The air supply mechanism (monitoring device) 28 includes one blower 29, one switching valve 30, three constant flow rate valves 31, three check valves 32, and a differential pressure sensor 33. The blower 29 is connected to the switching valve 30 by a pipe 34a. The three bearings 40 are connected to the switching valve 30 by pipes 34b to 34d. A constant flow rate valve 31 and a check valve 32 are interposed in the pipes 34b to 34d, respectively, and a certain amount of air can be supplied only from the blower 29 toward the bearing 40. The differential pressure sensor 33 is arranged in the pipe 34e. One end of the pipe 34e is connected to the pipe 34a, and the other end of the pipe 34e is connected to the pump casing 12.

When the control unit 35 detects that the inside of the pump casing 12 has been operated in the air by the detection unit (not shown), the control unit 35 drives the blower 29 and switches the switching valve 30 at predetermined time intervals to switch the three switching valves 30. Air is sequentially supplied to the bearing 40. The air supplied to the bearing 40 is the through hole 47 of the back shell 46, the gap between the sliding body 42 and the sleeve 22, the gap between the back shell 46 and the sliding body 42, and the back shell, as in the case of natural convection. Heat is adsorbed to each component of the bearing 40 through the gap between the anti-vibration member 61 and the air gap of the anti-vibration member 61. The air that has passed through the upper and lower sliding body units flows out from the upper and lower sides of the cover case 66 to the outside.

In this way, the control unit 35 can determine (detect) the gap between the rotating shaft 21 and the sliding body 42 based on the pressure difference between the pipe 34a and the pump casing 12 obtained from the detection result of the differential pressure sensor 33. .. Further, by supplying air to the bearing 40, the sliding body 42, the back shell 46, and the vibration isolator member 61 can be reliably cooled. Therefore, it is possible to effectively prevent seizure of the rotating shaft 21 due to excessive heat generation of the sliding body 42.

As described above, in the bearing 40 of the present embodiment, since air flows in the through hole 47 of the back shell 46, the sliding body 42 can be cooled via the back shell 46. Further, since air flows into the gap formed between the back shell 46 and the sliding body 42 by the concave groove 53 provided on the inner peripheral surface 49 of the back shell 46, the cooling efficiency of the sliding body 42 and the back shell 46 is increased. Can be improved. Since the cover case 66 is provided with the ventilation holes 69, the sliding body 42 and the back shell 46 can be cooled by air cooling by natural convection or forced air cooling by the air supply mechanism 28. Since the ridges 64 formed on the vibration isolator member 61 on the outer periphery of the back shell allow air to flow to the outer peripheral surface 56 side of the back shell 46, the back shell 46 can be reliably cooled, and the sliding body is passed through the back shell 46. 42 can be cooled.

Since the sliding body 42 can be effectively air-cooled by these cooling actions, seizure of the rotating shaft 21 on the sliding body 42 can be prevented. As a result, in the vertical shaft pump 10 that employs the bearing 40, it is not necessary to stop the drive of the drive unit 26 for cooling, so that the aerial operation can be continuously executed, and the function as the advance standby type is fully exhibited. can. Moreover, since the through hole 47 is provided in the back shell 46 instead of the sliding body 42, it is possible to prevent a decrease in the rigidity of the sliding body 42 and prevent the sliding body 42 from affecting the holding of the rotating shaft 21.

The back shell 46 is composed of an inner ring member 48 and an outer ring member 54, and a screw groove 52 forming a through hole 47 is formed on the outer peripheral surface 50 of the inner ring member 48. It can be reliably formed on the back shell 46. In particular, if the through holes 47 are formed in a spiral shape as in the present embodiment, the distance through which the air flows can be lengthened, so that a time for heat exchange can be secured and the cooling efficiency of the back shell 46 can be improved. Further, since the through hole 47 is formed on the outer peripheral surface 50 of the inner ring member 48 or the inner peripheral surface 55 of the outer ring member 54, it can be formed into a complicated shape such as a labyrinth structure.

Since the inner ring member 48 and the outer ring member 54 are fixed by the fixing pin 59, they are not loosened and disassembled by the rotation of the rotating shaft 21. Since the vibration isolator 61 is composed of two or more bump foil bearings 62, it can have a damping function against vibration of the rotating shaft 21. Further, since air also flows in the anti-vibration member 61, the heat resistant temperature of the anti-vibration member 61 can be improved.

(Second Embodiment)
FIG. 6 shows the bearing 40 of the second embodiment. In this second embodiment, a set of sliding body units including the sliding body 42, the back shell 46, and the vibration isolator 61 is arranged in the cover case 66. The outer peripheral wall 67 of the cover case 66 is not provided with a ventilation hole 69. Other configurations are the same as those in the first embodiment.

(Third Embodiment)
FIG. 7 shows the bearing 40 of the third embodiment. This third embodiment is different from the second embodiment in that the configuration of the back shell 46 is changed. The configuration other than the back shell 46 is the same as that of the first embodiment.

The back shell 46 is composed of one cylindrical member. At one end (lower end of FIG. 7) of the back shell 46, a protruding portion 51 for holding the sliding body 42 and a protruding portion 57 for holding the anti-vibration member 61 are provided. A linear through hole 47 penetrating in the axial direction of the rotating shaft 21 is provided between the inner peripheral surface 49 and the outer peripheral surface 56 of the back shell 46.

The bearings 40 of the second embodiment and the third embodiment as described above can obtain the same operations and effects as those of the first embodiment. Of course, two or more sets of the sliding body units shown in the third embodiment may be arranged in the cover case 66.

The bearing 40 of the present invention is not limited to the configuration of the above embodiment, and various modifications can be made.

For example, the through hole 47 may be provided separately from the screw groove 52 for assembling the inner ring member 48 and the outer ring member 54. Further, the groove forming the through hole 47 may be provided in only one of the inner ring member 48 and the outer ring member 54, or may be provided in both. Moreover, the shape of the groove forming the through hole 47 can be changed as needed as long as it communicates from one end to the other end of the back shell 46.

The fixing structure of the inner ring member 48 and the outer ring member 54 is not limited to the screw groove 52, the screw protrusion 58, and the fixing pin 59, and can be changed as needed. Further, the anti-vibration member 61 is not limited to the configuration using the bump foil bearing 62, and can be changed as needed.

The article using the bearing 40 of the present invention is not limited to the vertical axis pump 10 in which the rotating shaft 21 is arranged in the vertical direction, and may be a horizontal axis pump in which the rotating shaft is arranged in the horizontal direction, other than the pump that discharges the liquid. It may be an article. That is, any article having a rotation axis can be applied, and the same action and effect can be obtained.

1 ... Water absorption tank 2 ... Installation floor 10 ... Vertical pump 12 ... Pump casing 13 ... Pumping pipe 14 ... Straight pipe 15 ... Vane casing 16 ... Bearing casing 17 ... Bellmouth 18 ... Discharge pipe 19 ... Discharge elbow 21 ... Rotating shaft 22 ... Sleeve 24 ... Impeller 26 ... Drive unit 28 ... Air supply mechanism 29 ... Blower 30 ... Switching valve 31 ... Constant flow valve 32 ... Check valve 33 ... Differential pressure sensor 34a to 34e ... Piping 35 ... Control unit 40 ... Bearing 42 ... Sliding body 43 ... Shaft hole 44 ... Outer surface 46 ... Back shell 47 ... Through hole 48 ... Inner ring member 49 ... Inner peripheral surface 50 ... Outer surface 51 ... Protruding part 52 ... Screw groove (groove forming the through hole)
53 ... concave groove 54 ... outer ring member 55 ... inner peripheral surface 56 ... outer peripheral surface 57 ... protruding part 58 ... screw protrusion 59 ... fixing pin 61 ... anti-vibration member 62 ... bump foil bearing 63 ... outer peripheral part 64 ... convex strip 66 ... Cover case 67 ... Outer wall 68 ... End wall 69 ... Vent 70 ... Fixing pin

Claims (8)

Sliding bodies arranged on the outer circumference of the rotating shaft,
A back shell that is arranged on the outer circumference of the sliding body and holds the sliding body is provided.
Wherein between the inner and outer circumferential surfaces of the back shell, a through hole penetrating in the axial direction of the rotary shaft is provided, et al is,
A bearing having a groove provided on the inner peripheral surface of the back shell in a direction away from the sliding body. The bearing according to claim 1, wherein a casing having a ventilation hole communicating with the through hole is arranged on the outer periphery of the back shell. Sliding bodies arranged on the outer circumference of the rotating shaft,
With a back shell arranged on the outer circumference of the sliding body and holding the sliding body
With
A through hole penetrating in the axial direction of the rotating shaft is provided between the inner peripheral surface and the outer peripheral surface of the back shell.
A bearing in which a casing having a ventilation hole communicating with the through hole is arranged on the outer periphery of the back shell. The back shell has an inner ring member arranged on the outer periphery of the sliding body and an outer ring member arranged on the outer periphery of the inner ring member.
The bearing according to any one of claims 1 to 3 , wherein a groove forming the through hole is provided on at least one of the outer surface of the inner ring member and the inner surface of the outer ring member. The bearing according to claim 4 , wherein the groove forming the through hole is formed in a spiral shape. The bearing according to claim 4 or 5 , wherein the inner ring member and the outer ring member are fixed by a fixing pin. On the outer periphery of the back shell, a vibration-proof member having a plurality of ridges abutting on the outer peripheral surface of the back shell is arranged.
The bearing according to any one of claims 1 to 6, wherein the ridges extend along the axial direction of the rotating shaft and are provided at intervals in the circumferential direction of the rotating shaft. The anti-vibration member has two or more bump foil bearings made of a metal plate having a uniform thickness.
The two or more bump foil bearings are arranged in the axial direction of the rotating shaft, and the ridges formed on the adjacent bump foil bearings are arranged at different positions in the circumferential direction of the rotating shaft. Item 7. The bearing according to item 7.

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