JP2013198339A - Rotary electric machine and sealing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress water and the like from flowing in a stator frame of a rotary electric machine.SOLUTION: A sealing mechanism 50 includes: an end plate-side fixed portion 60 which is fixed to an end plate 21, and has a plurality of fixed-side grooves formed along a radial direction so as to surround a shaft through hole, an inner peripheral surface on a cylinder being formed radially outside the fixed-side grooves; a rotary shaft-side movable portion 70 which is fixed to a rotary shaft 10, and has a movable-side groove formed to form a labyrinth seal with the fixed-side grooves and also has a water receiving portion formed gradually increasing in diameter; and a lid member 80 which is fixed to the end plate-side fixed portion and formed such that a part of the rotary shaft-side movable portion is closed with the axial outside.

Description

  The present invention relates to a rotating electrical machine and a shaft seal mechanism.

  A rotating electrical machine such as an electric motor has a rotating shaft that serves as an output shaft, a rotor that rotates together with the rotating shaft, a stator that surrounds the rotor, and a stator frame that covers the stator from the outside.

  The stator frame includes end plates on both axial sides of the rotor, and a main body that surrounds the rotor from the outside in the radial direction. The rotating shaft is rotatably supported by a bearing attached to the end plate.

  The seal mechanism in the gap between the stator frame and the rotating shaft includes a contact type in which a sealing material such as rubber contacts the rotating shaft and a non-contact type. As the contact type, a rubber oil seal or the like is known, and as the non-contact type, a labyrinth method or the like is known. As the labyrinth method, for example, one disclosed in Patent Document 1 is known. This sealing mechanism is for suppressing the inflow of water sprayed from the outside of the stator frame.

JP-A-4-168946

  In the case of a rotating electrical machine in which the rotating shaft is arranged horizontally, a general labyrinth type seal mechanism is designed to prevent inflow of water into the stator frame from water that is sprayed from the horizontal or obliquely from above to below. The suppression effect is high. This is because water on the outer periphery of the rotating shaft is blown outward by centrifugal force due to rotation, and the blown water can be effectively discharged by a fringer or the like.

  However, it may be difficult to suppress the inflow of water that blows upward from below the rotating shaft.

  The present invention has been made to solve the above-described problems, and an object thereof is to more effectively suppress the inflow of water or the like into the stator frame.

  In order to achieve the above object, a rotating electrical machine according to the present invention includes a rotating shaft that rotates around a horizontal axis, and is fixed to the rotating shaft so as to surround a part of the rotating shaft from the outside in the radial direction. An annular rotor that rotates around the shaft together with a shaft, an annular stator that is formed so as to surround the rotor from the outside in the radial direction, and a main body that surrounds the stator from the outside in the radial direction; An end plate attached to an axial end of the main body and formed with a shaft through hole through which the rotation shaft passes, and a stator frame for accommodating the stator and the rotor therein, and the end A flat surface which is formed on a plate and is attached to a bearing configured to rotatably support the rotating shaft, and which spreads in a radial direction at an axial end of a portion protruding outward in the axial direction. Formed on this flat surface the rotating shaft A rotation having a bearing housing portion formed so as to penetrate, and a seal mechanism that is disposed in the vicinity of the bearing outside in the axial direction of the stator frame and prevents liquid from flowing into the stator frame In the electric machine, the sealing mechanism is fixed to the end plate, and a plurality of fixed side grooves are formed along the radial direction so as to surround the shaft through hole on the radially outer side of the shaft through hole. Also, the end plate side fixing portion in which the radially outer side is formed with an inner peripheral surface on the cylinder, and the outer peripheral portion of the rotating shaft are fixed to the outer peripheral portion so as to surround the concave portion of the fixing side groove. The movable side groove is formed so that the position corresponding to the protruding part is recessed, and the movable side groove is arranged so as to maintain an axial gap in the fixed side groove, and the axial direction of the movable side groove Axial on the outside A water receiving portion is formed so as to spread outward in the radial direction so that the diameter increases toward the outside, and a cylindrical surface is formed on the radially outer side of the movable side groove, and the cylindrical surface is formed on the inner peripheral surface. A rotating shaft side movable portion disposed so as to maintain a radial gap of 1 and a member fixed to the end plate side fixing portion and configured to block a part of the rotating shaft side movable portion from the outside in the axial direction And surrounding the radially outer portion of the upper half of the water receiving portion with respect to the axial center while maintaining the second radial gap, and surrounding the upper half of the outer periphery of the rotating shaft while maintaining the third radial gap, and An upper semi-waterproof portion formed so as to be arranged at an axial interval at an axial end portion of the water receiving portion, and a portion below the axial center of the water receiving portion to be blocked from the axially outer side. Formed, and a discharge channel is formed inside, below the flat surface. And a lower semi-waterproof portion that opens downward.

  The sealing mechanism according to the present invention includes a rotating shaft that rotates around a horizontal axis, and is fixed to the rotating shaft so as to surround a part of the rotating shaft from the outside in the radial direction. An annular rotor, an annular stator formed so as to surround the rotor from the outside in the radial direction, a body portion surrounding the stator from the outside in the radial direction, and an axial direction of the body portion An end plate that is attached to an end and formed with a shaft through hole through which the rotation shaft passes, and is formed in the end plate, and a stator frame that accommodates the stator and the rotor inside. A bearing configured to rotatably support the rotating shaft is attached, and a flat surface extending in the radial direction is formed at the axial end of the portion protruding outward in the axial direction. So that the rotating shaft penetrates the flat surface In the rotating electrical machine sealing mechanism having a bearing housing portion formed, the sealing mechanism is disposed in the vicinity of the bearing on the axially outer side of the stator frame, and liquid flows into the stator frame. A plurality of fixed side grooves are formed along the radial direction so as to surround the shaft through hole on the radially outer side of the shaft through hole. The outer side in the radial direction corresponds to the end plate side fixing portion in which the inner peripheral surface on the cylinder is formed, and the portion fixed to the outer peripheral portion so as to surround the outer peripheral portion of the rotating shaft, and the concave portion of the fixing side groove. A movable side groove is formed so that the position protrudes and the position corresponding to the protruding part is recessed, and the movable side groove is disposed so as to maintain an axial gap in the fixed side groove, and is axially outside of the movable side groove. On the outside in the axial direction A water receiving portion is formed so as to expand radially outward so that the diameter increases, and a cylindrical surface is formed radially outward of the movable side groove, and the cylindrical surface is formed on the inner peripheral surface with a first surface. A rotating shaft side movable part arranged so as to maintain a radial gap, and a member fixed to the end plate side fixed part and formed so as to block a part of the rotating shaft side movable part from the outside in the axial direction, Surrounding the outer half of the water receiving portion in the radial direction of the upper half of the water receiving portion while maintaining a second radial gap and surrounding the upper half of the outer periphery of the rotating shaft while maintaining a third radial clearance, An upper semi-waterproof portion formed so as to be arranged at an axial interval at an axial end portion of the receiving portion, and a portion lower than the axial center of the water receiving portion is formed to be closed from the outside in the axial direction. The discharge channel is formed in the inside, and is downward below the flat surface. And a lid member having a lower semi-waterproof portion that opens.

  According to the present invention, it is possible to effectively suppress the inflow of water or the like into the stator frame of the rotating electrical machine.

1 is a partially cutaway partial front sectional view schematically showing a rotating electrical machine according to an embodiment of the present invention. It is the expansion front sectional view to which the II section of Drawing 1 was expanded. It is the expansion front sectional view to which the III section of Drawing 1 was expanded. It is a schematic front view which shows the end plate fixing | fixed part of FIG. It is a schematic front view which shows the rotating shaft side movable part of FIG. It is a schematic front view which shows the cover member of FIG. It is a schematic side view of the VII-VII arrow of FIG.

  Hereinafter, an embodiment of a rotating electrical machine according to the present invention will be described with reference to FIGS.

  FIG. 1 is a partially cutaway partial front sectional view schematically showing a rotating electrical machine of the present embodiment. FIG. 2 is an enlarged front sectional view in which a portion II in FIG. 1 is enlarged. FIG. 3 is an enlarged front sectional view in which a portion III in FIG. 1 is enlarged.

  FIG. 4 is a schematic front view showing the end plate 21 fixing portion of FIG. 1 alone. FIG. 5 is a schematic front view showing the rotating shaft side movable portion 70 of FIG. 2 alone. FIG. 6 is a schematic front view showing the lid member 80 of FIG. 1 alone. FIG. 7 is a schematic side view taken along arrow VII-VII in FIG. In FIG. 7, the attachment surface 25a formed in the bearing housing portion 25 is virtually indicated by a two-dot chain line.

  First, the configuration of the rotating electrical machine of the present embodiment will be described.

  The rotating electrical machine of this embodiment includes a rotating shaft 10, a rotor 12, a stator 14, a stator frame 20, and a seal mechanism 50.

  The rotating shaft 10 rotates around a horizontal axis. In the case of an electric motor, this is the output shaft.

  The rotor 12 is an annular member, and is fixed to the rotation shaft 10 so as to surround a part of the rotation shaft 10 from the outside in the radial direction, and rotates around the shaft together with the rotation shaft 10.

  The stator 14 has an annular shape formed so as to surround the rotor 12 from the outside in the radial direction.

  The stator frame 20 includes a main body portion 22 that surrounds the stator 14 from the outside in the radial direction, and an end plate 21 that is attached to an axial end portion of the main body portion 22. The stator frame 20 accommodates the stator 14 and the rotor 12 therein. Radiation fins 23 are attached to the main body 22. The heat radiating fins 23 are for radiating heat generated from the stator winding 15 and the like to the outside.

  A bearing housing portion 25 is formed on each end plate 21, and a bearing 16 is attached to the bearing housing portion 25. The bearing 16 supports the rotating shaft 10 in a rotatable manner.

  The bearing housing portion 25 protrudes outward in the axial direction (right side in FIG. 1), and a mounting surface 25a that faces the outer side in the axial direction and to which the constituent members of the seal mechanism 50 are attached is formed at the tip of the protruding portion. Has been. A shaft through hole 26 through which the rotary shaft 10 can pass is formed in the mounting surface 25a. The mounting surface 25a is a flat surface extending in the radial direction and is substantially circular.

  The seal mechanism 50 is disposed near the bearing 16 on the outer side in the axial direction of the stator frame 20. The seal mechanism 50 seals a gap formed between the stator frame 20 and the rotary shaft 10 and suppresses the inflow of water sprayed from the outside of the stator frame 20.

  Here, details of the seal mechanism 50 will be described.

  The seal mechanism 50 includes an end plate side fixed portion 60, a rotary shaft side movable portion 70, and a lid member 80.

  The end plate side fixing portion 60 is formed around the shaft through hole 26 of the bearing housing portion 25. The shaft through hole 26 is formed such that when the rotary shaft 10 passes through, the inner periphery thereof maintains a predetermined gap 90 with respect to the outer peripheral surface of the rotary shaft 10 (FIGS. 2 and 3). The radial dimension of the gap 90 is such that the outer peripheral surface of the rotary shaft 10 does not contact the inner surface of the shaft through hole 26 when the rotary shaft 10 rotates.

  The end plate side fixing portion 60 is formed with a plurality of fixing side grooves 61 (FIG. 4). The fixed side groove 61 is formed along the radial direction so as to surround the shaft through hole 26 on the radially outer side of the shaft through hole 26.

  An edge of the fixed side groove 61, that is, a protruding portion 61a protruding in the axial direction is configured to enter a recessed portion of the movable side groove 71 described later. Details will be described later.

  Further, an inner peripheral surface 62 facing inward in the radial direction is formed on the outer side in the radial direction of the fixed side groove 61. This is a surface facing the outer peripheral surface of the rotating shaft side movable unit 70 described later.

  The rotating shaft side movable portion 70 is a member fixed to the outer peripheral portion so as to surround the outer peripheral portion of the rotating shaft 10.

  The outer peripheral surface of the rotating shaft side movable portion 70 is cylindrical, and is arranged on the inner peripheral surface 62 of the end plate side fixing portion 60 so as to maintain the first radial gap 91 (FIGS. 2 and 3).

  A movable side groove 71 (FIG. 5) is formed in the rotary shaft side movable part 70. The movable groove 71 is formed such that a position corresponding to the recessed portion of the fixed side groove 61 protrudes and a position corresponding to the protruding portion is recessed. The movable side groove 71 is disposed so as to maintain the first axial gap 97 in the fixed side groove 61, and forms a so-called labyrinth seal together with the fixed side groove 61.

  A water receiving portion 72 is formed outside the outer peripheral surface in the axial direction and outside the movable side groove 71 in the axial direction. The water receiving portion 72 is formed so as to expand radially outward so that the diameter increases toward the outer side in the axial direction, and the inner peripheral shape thereof is a partial conical shape having a larger diameter on the outer side in the axial direction. The portion with the smallest diameter is in contact with the outer peripheral surface of the rotating shaft 10.

  A stepped portion 76 is formed on the outer side in the radial direction of the water receiving portion 72 so as to have a smaller diameter than the outer peripheral portion. The stepped portion 76 becomes a part of a discharge channel 95 described later.

  The lid member 80 is fixed to the attachment surface 25a. The lid member 80 is a member formed so that a part of the rotary shaft side movable portion 70 is closed on the outer side in the axial direction, and as shown in FIGS. 6 and 7, a perforated disc-shaped inner plate 88 is formed. And an upper semi-waterproof part 81 and a lower semi-waterproof part 82.

  The inner plate 88 is formed in a disc shape with a round hole 88a in the center and has a radially extending surface, and the round hole 88a is larger than the diameter of the shaft through hole 26. The inner plate 88 is disposed so as to surround the shaft through hole 26 and is fixed to the bearing housing portion 25 by a bolt or the like on the end plate 21. At this time, the inner side of the round hole 88 a is fixed so as to maintain the second radial gap 92 (FIG. 2) with respect to the upper half portion from the axial center of the stepped portion 76.

  The width of the second radial gap 92 is such that no contact occurs when the rotary shaft 10 rotates and the stepped portion 76 moves in the circumferential direction. That is, the width is such that the inner plate 88 does not contact the stepped portion 76 even if there is a predetermined rotational shake.

  The upper semi-waterproof portion 81 includes a partial ring plate 81b and an outer plate 81a.

  The partial ring plate 81b is a partial annular plate attached to the inner plate 88, and is formed with a predetermined length in the axial direction. The partial ring plate 81b has a diameter larger than that of the round hole 88a of the inner plate 88, and is formed so that the lower side is slightly lower than the shaft center and the shaft center covers from the upper side. That is, the partial ring plate 81b is slightly larger than the semicircle.

  The outer plate 81a has a surface extending in the radial direction, and is attached to the axially outer end portion of the partial ring plate 81b. Similar to the partial ring plate 81b, it is a partially perforated disc that is slightly larger than the semicircle. The outer plate 81 a is formed so as to surround the outer peripheral surface of the rotating shaft 10 while maintaining the third radial gap 93 (FIG. 2). The radial width of the third radial gap 93 is such that it does not come into contact with the outer peripheral surface of the rotary shaft 10 even when the rotary shaft 10 is rotating, and the axial width of the second axial gap 98 described later. Smaller than.

  Further, the outer plate 81 a is arranged at a predetermined second axial gap 98 at the axial end of the water receiving portion 72. The axial width of the second axial gap 98 is such that no contact is made when the rotating shaft 10 rotates and the water receiving portion 72 moves in the circumferential direction.

  Next, the lower half waterproof part 82 will be described. The lower semi-waterproof portion 82 is a hollow, substantially rectangular parallelepiped box shape having an opening formed below. The inside of the box forms a discharge channel 95 and is discharged to the outside through the opening. The opening of the lower semi-waterproof portion 82 is formed in a portion that protrudes downward from the lower end of the mounting surface 25a.

  The discharge channel 95 can discharge the water accumulated in the stepped portion 76 (FIG. 3). The state of discharge will be described later.

  The upper end of the lower half waterproof portion 82 is fixed so as to maintain a fourth radial gap 94 with respect to the radially outer side of the lower half portion from the axial center of the water receiving portion 72. The width of the fourth radial gap 94 is formed in the same manner as the width of the second radial gap 92 described above.

  Next, an example of a state in which water sprayed from the right side to the left side in FIGS. 2 and 3 is prevented from flowing into the stator frame 20 will be described with respect to the waterproof action of the present embodiment.

  First, the state of waterproofing above the rotation center, that is, the operation of the upper half waterproof part 81 will be described.

  When the water is sprayed horizontally on the end plate 21, the sprayed water flows from the third radial gap 93 between the outer plate 81 a and the rotating shaft 10 and reaches the water receiving portion 72. At this time, since the rotating shaft 10 is rotating, the water in the water receiving portion 72 flows radially outward along the inclined surface of the water receiving portion 72 by centrifugal force.

  After water has reached the outer side (the right side in FIG. 1) of the water receiving part 72 in the axial direction (the right side in FIG. 2), it is sprayed on the outer plate 81a or the partial ring plate 81b and then downward Flowing into. After flowing downward, it flows on the outer peripheral surface of the rotating shaft 10 and is discharged outside.

  On the other hand, a part of the water sprayed on the partial ring plate 81 b remains in the stepped portion 76 and then flows into the second radial gap 92 between the inner plate 88 and the water receiving portion 72. However, since the second axial gap 98 between the water receiving portion 72 and the outer plate 81a is wider than the second radial gap 92, more water flows through the second axial gap 98. . Even if water flows into the second radial gap 92, the inflow is suppressed by the labyrinth seal.

  Thereby, it can suppress that water flows in into the stator frame 20 from the upper half part of an axial center.

  Next, the operation of the lower half waterproof portion 82 will be described.

  When water is sprayed horizontally on the end plate 21, the sprayed water flows from the fourth radial gap 94 between the lower semi-waterproof portion 82 and the water receiving portion 72, and radially outside the stepped portion 76. Flows into the space. The water that has flowed into the space flows into the discharge channel 95 in the lower semi-waterproof portion 82 and is discharged from the opening below the lower semi-waterproof portion 82 in the direction of the arrow X shown in FIG. At this time, a part of the water that has flowed into the space tends to flow into the first radial gap 91, but in the radial direction of the discharge flow path 95 rather than the radial width of the first radial gap 91. Since the width is wider, it tends to flow into the discharge channel 95. Thereby, it can suppress that water flows in into the stator frame 20 from the upper half part of an axial center.

  In addition, since the lower semi-waterproof portion 82 has a small opening portion on the outside in the axial direction, it is difficult for water sprayed horizontally to flow in.

  Further, as described above, the opening of the discharge channel 95 is formed below the lower end of the mounting surface 25a. If the opening is formed above the lower end of the mounting surface 25a, the water sprayed on the mounting surface 25a flows upward in the discharge flow path 95, that is, flows backward to form a gap. It may reach 90 and flow into the stator frame 20.

  On the other hand, in this embodiment, since the said opening part is formed below the lower end of the attachment surface 25a, it suppresses that the water sprayed on the lower side in the attachment surface 25a flows backward as mentioned above. it can.

  As can be seen from the above description, according to this embodiment, the inflow of water or the like into the stator frame 20 can be more effectively suppressed. Further, since the discharge channel 95 is provided in the lower semi-waterproof portion 82 of the lid member 80, no additional work or the like for forming the channel in the end plate 21 is required. Therefore, the seal mechanism 50 can be manufactured at a lower cost.

  The description of the present embodiment is an example for explaining the present invention, and does not limit the invention described in the claims. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

  For example, a groove extending vertically outside the fixed side groove 61 and below the center of the rotating shaft 10 may be provided so as to easily flow into the discharge channel. Moreover, although the end plate side fixing | fixed part 60 is formed in the bearing housing part 25, it is not restricted to this. It is good also as a member which can be attached or detached to the bearing housing part 25. FIG.

  Further, in this example, the bearing housing portion 25 is configured integrally with the end plate 21, but may be a separate body.

DESCRIPTION OF SYMBOLS 10 ... Rotary shaft, 12 ... Rotor, 14 ... Stator, 15 ... Stator winding, 16 ... Bearing, 20 ... Stator frame, 21 ... End plate, 22 ... Main part, 23 ... Radiation fin, 25 ... Bearing Housing: 25a ... Mounting surface, 26 ... Shaft through hole, 50 ... Seal mechanism, 60 ... End plate side fixing part, 61 ... Fixed side groove, 61a ... Projection part, 62 ... Inner peripheral surface, 70 ... Rotating shaft side movable part, 71 ... Moving side groove, 72 ... Water receiving portion, 76 ... Step portion, 80 ... Lid member, 81 ... Upper semi-waterproof portion, 81a ... Outer plate, 81b ... Partial ring plate, 82 ... Lower semi-waterproof portion, 88 ... Inner plate , 88a ... round hole, 90 ... gap, 91 ... first radial gap, 92 ... second radial gap, 93 ... third radial gap, 94 ... fourth radial gap, 95 ... for discharge Flow path, 97 ... first axial gap, 98 ... second axial gap

Claims (3)

A rotation axis that rotates around a horizontal axis;
An annular rotor fixed to the rotary shaft so as to surround a part of the rotary shaft from the outside in the radial direction and rotating around the axis together with the rotary shaft;
An annular stator formed so as to surround the rotor from outside in the radial direction;
A main body that surrounds the stator from the outside in the radial direction; and an end plate that is attached to an axial end of the main body and has a shaft through hole through which the rotation shaft passes. A stator frame that houses the child and the rotor;
A flat surface that is formed on the end plate and that is attached to a bearing configured to rotatably support the rotating shaft and extends radially in the axial end portion of the portion protruding outward in the axial direction. A bearing housing part formed so that the rotating shaft passes through the flat surface,
A seal mechanism that is disposed in the vicinity of the bearing on the outer side in the axial direction of the stator frame, and suppresses liquid from flowing into the stator frame;
In a rotating electrical machine having
The sealing mechanism is
A plurality of fixed side grooves are formed along the radial direction so as to surround the shaft through hole on the outer side in the radial direction of the shaft through hole, and the outer side in the radial direction of the fixed side groove on the cylinder is fixed to the end plate. An end plate side fixing portion formed with an inner peripheral surface;
A movable side groove is formed so that the position corresponding to the recessed part of the fixed side groove protrudes and the position corresponding to the protruding part is recessed, fixed to the outer periphery so as to surround the outer periphery of the rotating shaft. The movable side groove is disposed so as to maintain an axial gap in the fixed side groove, and extends outward in the radial direction so that the diameter increases toward the outer side in the axial direction on the outer side in the axial direction of the movable side groove. A rotary shaft side movable part formed with a water receiving part, a cylindrical surface formed radially outward of the movable side groove, and the cylindrical surface being arranged to maintain a first radial gap on the inner peripheral surface When,
A member that is fixed to the end plate side fixing portion and is formed so as to block a part of the movable portion on the rotating shaft side from the outside in the axial direction. The outer half of the outer periphery of the rotating shaft is surrounded while maintaining a third radial gap, and is disposed at an axial interval at the axial end of the water receiving portion. An upper semi-waterproof portion formed as described above and a portion lower than the axial center of the water receiving portion are closed from the outside in the axial direction so as to form a discharge channel inside and below the flat surface. A lid member comprising a lower semi-waterproof part that opens downward at
A rotating electric machine comprising: The lower semi-waterproof portion is a hollow, substantially rectangular parallelepiped box shape having an opening formed below, and is configured to form a discharge channel on the inner side so that the liquid can be discharged from the opening. ,
The rotating electrical machine according to claim 1. A rotation axis that rotates around a horizontal axis;
An annular rotor fixed to the rotary shaft so as to surround a part of the rotary shaft from the outside in the radial direction and rotating around the axis together with the rotary shaft;
An annular stator formed so as to surround the rotor from outside in the radial direction;
A main body that surrounds the stator from the outside in the radial direction; and an end plate that is attached to an axial end of the main body and has a shaft through hole through which the rotation shaft passes. A stator frame that houses the child and the rotor;
A flat surface that is formed on the end plate and that is attached to a bearing configured to rotatably support the rotating shaft and extends radially in the axial end portion of the portion protruding outward in the axial direction. A bearing housing part formed so that the rotating shaft passes through the flat surface,
In a rotary electric machine sealing mechanism having
The seal mechanism is disposed in the vicinity of the bearing on the outer side in the axial direction of the stator frame, and suppresses inflow of liquid into the stator frame,
A plurality of fixed side grooves are formed along the radial direction so as to surround the shaft through hole on the outer side in the radial direction of the shaft through hole, and the outer side in the radial direction of the fixed side groove on the cylinder An end plate side fixing portion formed with an inner peripheral surface;
A movable side groove is formed so as to be fixed to the outer peripheral portion so as to surround the outer peripheral portion of the rotating shaft, and a position corresponding to the recessed portion of the fixed side groove protrudes and a position corresponding to the protruding portion is recessed. Thus, the movable side groove is disposed so as to maintain an axial gap in the fixed side groove, and the movable side groove extends outward in the radial direction so that its diameter increases toward the outer side in the axial direction. A rotating shaft-side movable portion that is formed so that a receiving portion is formed, a cylindrical surface is formed radially outward of the movable-side groove, and the cylindrical surface maintains a first radial gap on the inner peripheral surface; ,
A member that is fixed to the end plate side fixing portion and is formed so as to block a part of the movable portion on the rotating shaft side from the outside in the axial direction. The outer half of the outer periphery of the rotating shaft is surrounded while maintaining a third radial gap, and is disposed at an axial interval at the axial end of the water receiving portion. An upper semi-waterproof portion formed as described above and a portion lower than the axial center of the water receiving portion are closed from the outside in the axial direction so as to form a discharge channel inside and below the flat surface. A lid member comprising a lower semi-waterproof part that opens downward at
A sealing mechanism characterized by comprising:

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