Centrifugal pump

Abstract

An object of the present invention is to provide a centrifugal pump capable of suppressing dry sliding by facilitating discharge of air in a case to the outside of the case.SOLUTION: The centrifugal pump 1 includes the rotating blade member 70 which rotates around the axis of the shaft member 33, and the main body case 20. The rotating blade member 70 includes a bearing member 71 into which the shaft member 33 is inserted, a flange portion 78, a plurality of blade portions 90 erected on a flange surface 79 on one side of the flange portion 78 and radially extended in the radial direction, and a minute space S3 provided between the shaft member 33 and the bearing member 71 and communicating with the inside of the main body case 20. In the main body case 20, one space side S7 positioned on the upper side of the flange part 78 is provided, and in the baring member 71, a baring part communication path side S3 for communicating the minute space side S7 with the one space side S5 through a wall surface is provided.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a centrifugal pump. [Background technology]

[0002] Conventionally, centrifugal pumps for circulating fluid in closed circuits, such as the refrigerant circulation circuits of air conditioners and refrigerators, are known (see, for example, Patent Document 1). The centrifugal pump described in Patent Document 1 includes a rotating impeller member 12 housed in a main body case 34, as shown in FIG. 1 of Patent Document 1. The rotating impeller member 12 includes a bearing portion 14, a shaft member 64 inserted into the bearing portion 14, and a rotor magnet 32 ​​attached to a base end portion 18 surrounding the bearing portion 14. The rotating impeller member 12 rotates around the axis of the shaft member 64 by exciting a coil 210 (see FIG. 10 of Patent Document 1) disposed around the rotor magnet 32. When the rotating impeller member 12 rotates, fluid flows from a suction-side coupling member 42 into the main body case 34, through the main body case 34, and out of a discharge-side coupling member 46. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-133024 Summary of the Invention [Problem to be solved by the invention]

[0004] In the centrifugal pump described above, air bubbles and the like may occur between the bearing 14 and the shaft member 64. In this case, so-called dry sliding occurs, in which the bearing 14 and the shaft member 64 directly slide against each other, and wear may occur at the contact points between the bearing 14 and the shaft member 64. Therefore, removing the air bubbles is an issue from the perspective of improving the durability of the centrifugal pump. One possible solution is to expel the air bubbles to the outside using the fluid flowing through the main case 34. However, in the configuration described in Patent Document 1, the fluid is easily pushed radially outward from the shaft member 64 due to the rotation of the rotating impeller member 12. As a result, the pressure inside the main case 34 tends to be high on the inner circumferential surface side of the main case 34 and low on the shaft member 64 side. Therefore, due to the pressure difference, a fluid flow occurs inside the main case 34, passing between the inner circumferential surface of the main case 34 and the rotating impeller member 12 and the rotor magnet 32 ​​and toward the lower end of the shaft member 64. The fluid then enters the gap between the bearing portion 14 and the shaft member 64 from the lower end of the shaft member 64, which is slightly pressurized by the fluid flow. The fluid then flows toward the upper end of the shaft member 64 and exits through the upper end. However, because the fluid passes a long distance between the bearing portion 14 and the shaft member 64, from the lower end to the upper end, frictional resistance during the passage can make it difficult to expel air bubbles. Furthermore, in order to prevent displacement of the bearing portion 14, the upper end of the bearing portion 14 is often located close to the inner wall surface of the main body case 34. In this case, the space between the upper end of the bearing portion 14 and the inner wall surface of the main body case 34 is small, making it difficult for the fluid to flow smoothly between the upper end of the bearing portion 14 and the inner wall surface of the main body case 34. This makes it even more difficult to expel air bubbles from the upper end. Thus, if air bubbles are generated between the bearing portion 14 and the shaft member 64, it can be difficult to expel the air bubbles. This becomes more pronounced as the bearing portion 14 and the shaft member 64 become longer in the axial direction, and as the space between the upper end of the bearing portion 14 and the main body case 34 becomes smaller.

[0005] An object of the present invention is to provide a centrifugal pump that can suppress dry sliding by making it easier to discharge air inside the case to the outside of the case. [Means for solving the problem]

[0006] The present invention is a centrifugal pump comprising a rotating blade member that rotates around the axis of a shaft member, a main body case that houses the rotating blade member, and an inlet port and a discharge port that communicate with the inside and outside of the main body case, wherein the rotating blade member comprises a cylindrical bearing portion into which the shaft member is inserted, a flange portion that extends radially from the bearing portion, a plurality of blade portions that are erected on one axial side flange surface of the flange portion and extend radially in the radial direction, and a minute space that is provided between the shaft member and the bearing portion and communicates with the inside of the main body case, wherein a one-side space that is located on the one axial side of the flange portion is provided inside the main body case, and a bearing portion communication passage is provided in the bearing portion on the one axial side of the one-side flange surface that penetrates the wall of the bearing portion and communicates with the minute space and the one-side space.

[0007] According to the present invention, air bubbles generated in the microspace between the bearing portion and the shaft member can be easily discharged to the outside through the bearing portion communication passage penetrating the wall surface of the bearing portion. Furthermore, this configuration allows the fluid in the microspace to flow out of the microspace along its entire length, rather than continuously from the other axial end to the one end. This suppresses a decrease in flow rate due to frictional resistance between the fluid and the bearing member or the shaft member, making it easier to discharge air bubbles from the microspace. This makes it easy to discharge air even when the bearing portion and the shaft member are relatively long in the axial direction. Therefore, a centrifugal pump can be provided that can suppress dry sliding by facilitating the discharge of air from the case to the outside of the case.

[0008] Preferably, the blades have root portions extending radially from end faces abutting or facing the outer peripheral surface of the bearing, and the bearing communication passages are provided between adjacent root portions. With this configuration, when the end faces of the root portions abut the outer peripheral surface of the bearing, the blades and the outer peripheral surface of the bearing are continuous in the radial direction without any gaps. Therefore, compared to a configuration in which there is a gap between the blades and the outer peripheral surface of the bearing, there is no room for air bubbles to remain in the space between the blades and the bearing. Furthermore, with this configuration, since the bearing communication passages are provided between adjacent root portions, the fluid discharged from the bearing communication passages is prevented from flowing around the axis by the root portions and flows smoothly radially along the root portions. Therefore, the fluid discharged from the bearing communication passages flows smoothly in the intersecting direction along the blades without accumulating around the bearing, and this flow allows air bubbles to be discharged to the outside without being trapped around the bearing. Furthermore, even when the end face of the base portion faces the outer circumferential surface of the bearing portion, the fluid discharged from the bearing portion communication passage is prevented from flowing around the axis by the base portion and flows smoothly in the radial direction along the base portion, allowing the fluid discharged from the bearing portion communication passage to flow smoothly in the cross direction along the blade portion.

[0009] Preferably, the main body case includes a second space located on the other axial side of the flange, a fixing member for fixing the other axial end of the shaft member, the other axial end of the bearing having a second end face facing the fixing member, and a second communication passage for communicating the minute space with the second space between the second end face and the fixing member. With this configuration, when pressure in the second space increases, fluid can be induced to flow into the minute space via the second communication passage. The fluid that has flowed into the minute space can then be discharged to the outside of the main body case via the bearing communication passage and the first space.

[0010] At least a portion of the other-side communication passage may be formed by a first recessed portion that opens into the other-side end face.

[0011] At least a portion of the other-side communication passage may be formed by a second recessed portion that opens into the fixed member. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a centrifugal pump that can suppress dry sliding by making it easier to discharge air inside the case to the outside of the case. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view of a centrifugal pump according to the present invention. [Figure 2] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 3] FIG. 3 is an enlarged cross-sectional view of a main part of FIG. 2. [Figure 4] 3 is a cross-sectional view taken along line BB in FIG. 2. [Figure 5] 5 is a cross-sectional view taken along line CC in FIG. 4. [Figure 6] 5 is a cross-sectional view taken along line DD in FIG. 4. [Figure 7] 7A is a side view of the rotary blade member, FIG. 7B is an enlarged view of the vicinity of the bearing portion communication passage in FIG. 7A, FIG. 7C is an enlarged view of the vicinity of the other side communication passage in FIG. 7A, and FIG. 7D is a cross-sectional view showing variations of the blade portion. [Figure 8] 8(A) is a plan view of the rotary blade member, (B) is an enlarged view of the main part of FIG. 8(A), and (C) is a bottom view of the rotary blade member. [Figure 9] 9(A) is a plan view of the rotor magnet, and FIG. 9(B) is a cross-sectional view taken along line EE in FIG. 9(A). [Figure 10] 10(A) to 10(C) are diagrams showing variations of the rotary blade member. [Figure 11] 11(A) is a plan view of a fixing member according to a modified example, and FIG. 11(B) is a cross-sectional view taken along line FF in FIG. 11(A). [Figure 12] FIG. 10 is a longitudinal cross-sectional view of a rotary blade member according to a second embodiment, taken along an axis L. [Figure 13]13(A) is a plan view of a rotary vane member according to a first modified example of the second embodiment, FIG. 13(B) is an enlarged view of a main part of FIG. 13(A), and FIG. 13(C) is a cross-sectional view taken along line GG of FIG. 13(A). [Figure 14] 10A is a plan view of a shaft member according to a second modified example of the second embodiment, and FIG. 10B is a side view of the shaft member according to the second modified example of the second embodiment. [Figure 15] 15(A) is a plan view of a rotary blade member according to a third embodiment, (B) is a side view of the rotary blade member according to the third embodiment, and (C) is a cross-sectional view taken along line HH in FIG. 15(A). DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 9. A centrifugal pump 1 is a device that circulates a fluid F in a closed circuit, for example, in the refrigerant circulation circuit of an air conditioner or a refrigerator. As shown in FIG. 1, the centrifugal pump 1 includes a main body 10, a suction-side joint 11, and a discharge-side joint 12. The fluid F that flows into the main body 10 via the suction-side joint 11 flows out of the main body 10 via the discharge-side joint 12. In the following description, in the drawings, the direction along the axis L of a shaft member 33 (described later) is referred to as the axis L direction (axial direction), and the direction intersecting the axis L direction is referred to as the intersecting direction. The intersecting direction is also the radial direction of an imaginary circle centered on the axis L. One side of the axis L direction is referred to as the upper side, and the other side is referred to as the lower side. In the intersecting direction, the direction approaching the axis L is referred to as the inner side, and the direction away from the axis L is referred to as the outer side. These definitions of directions are provided for the convenience of explanation and do not limit the directions during manufacture or use of the centrifugal pump 1 according to the embodiment. Also, to avoid cluttering the drawings, some reference numerals may be omitted for parts with multiple similar components, such as the blade portion 90 described below.

[0015] As shown in FIG. 2, the main body 10 includes a main body case 20. The main body case 20 is a sealed case that includes a flow path for flowing a fluid F (shown in FIG. 3) and a space for accommodating the rotary vane member 70 (shown in FIG. 4), and includes a lower main body case 30 (rotor case) made of a metal material. As shown in FIG. 5, the lower main body case 30 forms the lower end of the main body case 20 and includes a cylindrical bearing accommodating portion 31 that opens upward and has a bottom. A fixed member 32 is accommodated within the bearing accommodating portion 31. The fixed member 32 is a cylindrical bushing that extends in the direction of the axis L and is fixed to the bearing accommodating portion 31 by press-fitting or the like. The lower end of a shaft member 33 is press-fitted into the center of the fixed member 32 and fixed in a non-rotatable state around the axis L. That is, the fixed member 32 functions as part of a bearing that supports the lower end of the shaft member 33. A rotor accommodating portion 34 is formed above the bearing accommodating portion 31.

[0016] The rotor accommodating portion 34 is formed in a cylindrical shape with a bottom and a larger diameter than the bearing accommodating portion 31, and is continuous with the upper end of the bearing accommodating portion 31. The rotor accommodating portion 34 accommodates the rotor magnet 93 of the rotary vane member 70. An extension portion 35 extending outward in the transverse direction is formed at the upper end of the rotor accommodating portion 34. The extension portion 35 is formed in a plate shape, and its outer edge is bent downward to form a flange-shaped outer peripheral connection portion 36. An upper main body case 40 made of a metal material is disposed above the lower main body case 30 configured in this manner. As shown in FIG. 2, the upper main body case 40 has a top wall 41 extending in the transverse direction. A bulge portion 41a is formed in the center of the top wall 41, bulging upward and extending in the transverse direction. The inner wall surface of the bulge portion 41a forms a part of the fluid introduction flow path S1, which will be described later. A peripheral wall 42 is formed at the outer edge of the top wall 41, bending downward and extending in the direction of the axis L. The lower end of the peripheral wall 42 is fixed to the outer peripheral connecting portion 36 of the lower main body case 30 by welding or the like.

[0017] As shown in FIG. 3, the peripheral wall 42 is formed with an inlet port 43 communicating with the inside and outside of the main body case 20. A tubular suction-side joint 11 is hermetically fixed to the inlet port 43 by welding, brazing, or the like. Furthermore, as shown in FIG. 4, the peripheral wall 42 is formed with an outlet port 44 communicating with the inside and outside of the main body case 20. A tubular discharge-side joint 12 is hermetically fixed to the outlet port 44 by welding, brazing, or the like. Between the lower main body case 30 and the upper main body case 40 configured in this manner, an impeller case 50 is disposed. As shown in FIG. 5, the impeller case 50 includes a side wall 51 disposed below the top wall 41 of the upper main body case 40. The side wall 51 faces the top wall 41 with a gap in the axial direction L and extends along the inner wall surface of the top wall 41 in the intersecting direction. A flow path opening 52 penetrating the axial direction L is formed in the center of the side wall 51.

[0018] A vertical wall 53 is formed continuously from the outer edge of the horizontal wall 51. The vertical wall 53 bends downward from the outer edge of the horizontal wall 51 and extends in the direction of the axis L. As shown in FIG. 4, the vertical wall 53 faces the inner circumferential surface of the peripheral wall 42 of the upper main body case 40 and the suction port 43 with a gap in the transverse direction. As shown in FIG. 5, a flange 54 is formed at the lower end of the vertical wall 53 and protrudes outward in the transverse direction. The flange 54 is fixed to the upper surface of the extension portion 35 of the lower main body case 30 and the inner wall surface of the peripheral wall 42 of the upper main body case 40 by welding or the like. By installing the blade case 50, the inside of the main body case 20 is divided into a fluid introduction flow path S1 surrounded by the bulging portion 41a and peripheral wall 42 of the upper main body case 40 and the blade case 50, and a blade accommodating space S2 (inside the blade case 50) surrounded by the lower main body case 30 and the blade case 50. As a result, the horizontal wall 51 and the vertical wall 53 of the blade case 50 form part of the fluid introduction flow path S1 and also form part of the blade accommodating space S2.

[0019] The blade housing space S2 is further divided into an upper space S7 (one side space) above a flange portion 78 (described later) and a lower space S8 (the other side space) below the flange portion 78. The fluid introduction passage S1 and the blade housing space S2 communicate with each other via the passage opening 52. With this configuration, as shown in FIG. 3, the fluid F introduced into the main body case 20 from the suction side joint 11 through the suction port 43 passes through the fluid introduction passage S1 toward the center of the main body case 20 and flows into the blade housing space S2 through the passage opening 52. As shown in FIG. 4, the fluid F is swept around the axis L by the blade portion 90 of the rotary blade member 70 and flows out of the main body case 20 from the discharge side joint 12 through the discharge port 44. The detailed structure of the rotary blade member 70 will be described later.

[0020] Next, another structure of the main body 10 will be described. As shown in FIG. 2, the main body 10 includes a coil case 60 that supports the main body case 20. The coil case 60 is formed in a generally box-like shape and includes a base portion 61 that constitutes the lower end of the main body 10 and a coil cover 62 that is attached to the base portion 61. A through-hole 61a that penetrates the base portion 61 in the direction of the axis L is formed in the center of the base portion 61, and the bearing accommodating portion 31 of the lower main body case 30 is disposed within the through-hole 61a. The coil cover 62 that constitutes the upper end surface of the coil case 60 abuts against the lower surface of the extension portion 35 of the lower main body case 30, and this abutment supports the main body case 20 in the direction of the axis L. A plurality of coil portions 63 are disposed within the coil case 60. The plurality of coil portions 63 are disposed at intervals along the circumferential direction of the rotor accommodating portion 34.

[0021] The coil section 63 includes a stator core 64 extending in the transverse direction, a bobbin case 65 arranged around the axis of the stator core 64, and a coil 66 wound around the axis of the stator core 64 via the bobbin case 65. In FIG. 2 , reference numeral 67 denotes a circuit board, reference numeral 67a denotes a terminal pin, reference numeral 68 denotes a cable insertion hole, reference numeral 69 denotes a cable, and reference numeral 69a denotes a connector. With this configuration, when a current is applied to the coils 66 via the cable 69, connector 69a, terminal pin 67a, and circuit board 67, the multiple coils 66 are excited, generating a magnetic force around the rotor accommodating section 34. This magnetic force then acts on the rotor magnet 93, causing the rotating blade member 70 to rotate around the axis L.

[0022] Next, the rotating blade member 70 will be described. The rotating blade member 70 is a member that rotates about the axis L of the shaft member 33, which is fixed non-rotatably by the fixed member 32, thereby causing the fluid F to flow about the axis L, and includes a bearing member 71 (bearing portion) extending in the direction of the axis L. The bearing member 71 includes a cylindrical columnar portion 71a. The shaft member 33 is inserted inside the columnar portion 71a. In FIG. 2, the inner circumferential surface of the columnar portion 71a abuts against the outer circumferential surface of the shaft member 33, but in reality, a small gap is generated between the columnar portion 71a and the shaft member 33, and this gap forms a minute space S3 through which the fluid F can pass. The lower end of the columnar portion 71a is supported by the fixed member 32 via an annular thrust bearing 72 that circumferentially surrounds the shaft member 33. A groove 73 recessed inward in the intersecting direction is formed on the outer peripheral surface of the columnar portion 71a, and a snap ring 74 is installed in the groove 73.

[0023] The snap ring 74 is a C-shaped ring made of a material such as metal or resin, and functions as a retainer that prevents a rotor magnet 93 (described later) from displacing downward. An upwardly protruding protrusion 75 is formed at the upper end of the bearing member 71. The protrusion 75 is a protective protrusion that prevents the blades 90 of the rotary blade member 70 from colliding with the top wall 41. As shown in FIG. 4 , the protrusions 75 are formed as a pair, one on one side in the transverse direction and the other on the other side in the transverse direction. The number and positions of the protrusions 75 are not limited to this, and may be one, two or more. Furthermore, when multiple protrusions 75 are provided, the protrusions do not necessarily have to be positioned opposite each other.

[0024] As shown in FIG. 4 , the protrusion 75 is formed in an arc shape extending around the axis L in a plan view. By forming the protrusion 75, a recess 71A is formed in the bearing member 71. The recess 71A is surrounded by the upper end surface of the portion of the bearing member 71 where the protrusion 75 is not provided and the circumferential end portion of the protrusion 75 around the axis L. The recess 71A opens upward and in the intersecting direction and extends in an arc shape along the circumferential direction around the axis L. The space inside the recess 71A forms a one-side communication passage S4 that communicates with the mini-space S3. Due to the formation of the one-side communication passage S4, a portion of the fluid F flowing from the fluid introduction passage S1 through the passage opening 52 to the blade housing space S2 flows into the mini-space S3 through the one-side communication passage S4. Furthermore, the fluid F in the upper space S7 flows into the mini-space S3 through the one-side communication passage S4. With this configuration, at the upper end of the bearing member 71, a structure (protrusion 75) that has the function of abutting against the top wall 41 and a structure (one-side communication passage S4) that has the function of communicating with the minute space S3 are arranged alternately around the axis L.

[0025] As shown in FIG. 5 , in the direction of the axis L, the bottom surface of the recess 71A (the lower end (end on the other axial direction) of the one-side communicating passage S4) is located below (on the other axial side) the upper end (end on one axial side) of the flow path opening 52. This makes it easy to ensure a flow path area for the one-side communicating passage S4, allowing the fluid F to flow efficiently from the fluid introduction flow path S1 and the upper space S7 toward the minute space S3 via the flow path opening 52 and the one-side communicating passage S4. In addition, in the direction of the axis L, the position of the lower end of the one-side communicating passage S4 can be appropriately selected as long as it is below the upper end of the flow path opening 52. For example, the position of the lower end of the one-side communicating passage S4 may be between the upper and lower ends of the flow path opening 52, or may be below the lower end of the flow path opening 52.

[0026] In this embodiment, as shown in FIG. 4, a gap is provided between the inner wall surface of the protrusion 75 and the outer wall surface of the shaft member 33 in the intersecting direction, and this gap forms an annular space 71B extending around the axis L. The annular space 71B is interposed between the one-side communicating passage S4 and the minute space S3, and connects the one-side communicating passage S4 and the minute space S3. By providing the annular space 71B, the fluid F flowing from the one-side communicating passage S4 to the minute space S3 flows into the minute space S3 from the entire circumference around the axis L via the annular space 71B. This ensures a sufficient flow rate of the fluid F flowing from the one-side communicating passage S4 into the minute space S3.

[0027] 3, the upper end of the protrusion 75 is located at approximately the same position in the direction of the axis L as the upper end of the shaft member 33. However, this configuration is not limited to this, and the position of the upper end of the protrusion 75 in the direction of the axis L may be above or below the upper end of the shaft member 33. Furthermore, the position of the upper end of the protrusion 75 in the direction of the axis L may be above or below the upper end of the flow path opening 52. Furthermore, the position of the upper end of the protrusion 75 in the direction of the axis L may be between the upper end and the lower end of the flow path opening 52. In other words, the upper end of the protrusion 75 may be located inside the flow path opening 52.

[0028] For example, although not shown, when the upper end (end on one axial side) of the bearing member 71 is positioned above (on one axial side) the upper end (end on one axial side) of the flow path opening 52, the upper end of the bearing member 71 protrudes into the fluid introduction flow path S1 and comes close to the top wall 41 of the main body case 20. Therefore, even if the bearing member 71 is unintentionally displaced in the direction of the axis L, the end of the bearing member 71 can be easily brought into contact with the top wall 41, thereby making it easier to suppress the displacement. Therefore, rattle of the bearing member 71 in the direction of the axis L can be suppressed. On the other hand, when the upper end of the bearing member 71 is positioned below the upper end of the flow path opening 52 as shown in FIG. 3 , the upper end of the bearing member 71 does not protrude into the fluid introduction flow path S1, making it less likely for the bearing member 71 to obstruct the flow of the fluid F in the fluid introduction flow path S1. Therefore, a sufficient flow path area for the fluid F flowing from the fluid introduction flow path S1 to the flow path opening 52 can be secured, thereby enabling the fluid F to flow smoothly in the fluid introduction flow path S1.

[0029] As shown in FIG. 6, the bearing member 71 is formed with a bearing communication passage S5 penetrating the wall of the bearing member 71 in the transverse direction. A pair of bearing communication passages S5 are formed, one on one side in the transverse direction and the other on the other side in the transverse direction. The bearing communication passages S5 penetrating in the transverse direction connect the upper space S7 and the minute space S3. Therefore, in the centrifugal pump 1, the fluid F that flows into the minute space S3 from the one-side communication passage S4 can be discharged from the bearing communication passage S5. The number of bearing communication passages S5 is not limited to the above number and may be one or more. Furthermore, when multiple bearing communication passages S5 are provided, they do not necessarily need to be positioned opposite each other. As shown in FIG. 7(A), the bearing communication passage S5 is provided below the protrusion 75 and above the one-side flange surface 79 (described later) in the axial direction L.

[0030] As shown in FIG. 7(B), the bearing portion communication passage S5 opens in the circumferential direction around the axis L, between a root portion 91 and a notch 92 of one blade portion 90 (described later) and a root portion 91 and a notch 92 of another blade portion 90. As shown in FIG. 7(C), a lower end surface 76 (other-side end surface) extending in the intersecting direction is formed at the lower end of the bearing member 71. The lower end surface 76 faces the upper end surface of the fixing member 32 in the direction of the axis L, and a slit 77 (first recessed portion) recessed upward and open downward is formed in this lower end surface 76. The slit 77 is tapered, becoming wider as it extends downward. As shown in FIG. 8(C), the slits 77 are formed on one intersecting side and the other intersecting side, forming a pair of intersecting communication passages S6 that extend in the intersecting direction and can communicate with the minute space S3. Therefore, as shown in Figure 5, when the rotating blade member 70 is housed in the main body case 20, the minute space S3 and the lower space S8 are connected via the other-side connecting passage S6 between the lower end surface 76 and the fixed member 32.

[0031] As shown in FIG. 8(A), a flange portion 78 extending outward in the transverse direction is formed on the outer peripheral surface of the bearing member 71. The flange portion 78 is formed in a disk shape with an outer diameter slightly smaller than the inner diameter of the rotor accommodating portion 34. The flange portion 78 divides the blade accommodating space S2 into an upper space S7 above the flange portion 78 and a lower space S8 below the flange portion 78. The upper space S7 communicates with the minute space S3 via the one-side communicating passage S4 (see FIG. 5). The lower space S8 communicates with the minute space S3 via the other-side communicating passage S6 (see FIG. 5). As shown in FIG. 8(B), the upper surface of the flange portion 78 constitutes a one-side flange surface 79, and an opening 80 opening upward is formed in the one-side flange surface 79. The openings 80 are formed in pairs on one side in the intersecting direction and the other side in the intersecting direction, and as shown in FIG. 8(C), they penetrate to the lower side to form flange through-holes 81.

[0032] The number of flange through holes 81 is not limited to the above number and may be one or two or more. Furthermore, when multiple flange through holes 81 are provided, they do not necessarily need to be positioned opposite each other. As shown in FIG. 8B , a pair of fitting holes 82 are formed in the one flange surface 79 at positions spaced apart from the flange through holes 81 around the axis L. A fitting protrusion 96 of a rotor magnet 93 (described later) fits into the fitting holes 82. In this embodiment, the fitting holes 82 into which the fitting protrusions 96 fit are through holes. However, the fitting holes 82 may be non-through recesses that open downward. A plurality of blade portions 90 are formed on the one flange surface 79. Each of the blade portions 90 stands on the one flange surface 79 and extends radially outward in the transverse direction, centered on the axis L.

[0033] As shown in FIG. 7B, each blade 90 has a root portion 91 extending outward in the transverse direction from the outer peripheral surface of bearing member 71. An end face 91a of root portion 91 on the inner side in the transverse direction abuts against the outer peripheral surface of bearing member 71. A notch 92 is formed at the upper end of root portion 91 by cutting out a corner. A gap is formed in the circumferential direction around axis L between the root portion 91 and notch 92 of one blade 90 and the root portion 91 and notch 92 of another blade 90 adjacent to that blade, and the bearing portion communicating passage S5 described above opens into this gap. With this configuration, because the end face 91a of root portion 91 abuts against the outer peripheral surface of bearing member 71, there is no room for air bubbles to accumulate between the bearing member 71 and blade 90. Furthermore, root portion 91 prevents air bubbles discharged from bearing portion communication passage S5 from flowing around axis L around bearing member 71. This prevents air bubbles from accumulating around axis L of bearing member 71, and allows the air bubbles to flow smoothly in the intersecting direction along blade portion 90.

[0034] 8(A), the flange through-hole 81 is also disposed between the root portion 91 and notch 92 of one blade 90 and the root portion 91 and notch 92 of another blade 90 adjacent to the first blade 90. As a result, the root portion 91 prevents the fluid F heading toward the flange through-hole 81 from flowing around the axis L of the bearing member 71. As a result, the fluid F flows smoothly along the root portion 91 without accumulating around the axis L of the bearing member 71. This prevents air bubbles from accumulating around the axis L of the bearing member 71. The bearing portion communicating passage S5 and the flange through-hole 81 are disposed in positions that are not sandwiched between the same blades 90 in the circumferential direction around the axis L. Specifically, if the space defined by adjacent blade portions 90 is defined as region R (shown only in FIG. 8(A)), multiple regions R are arranged around the axis L, but the bearing portion communication passage S5 and the flange through-hole 81 are not located in the same region R, but in different regions R. In other words, the opening 80 and the opening of the bearing portion communication passage S5 are arranged in one of the multiple regions R so as not to be located in the same region R. This configuration makes it difficult for the flow F1 of fluid F passing through the flange portion communication passage S9 (see FIG. 5), which will be described later, and the flow F3 of fluid F passing through the bearing portion communication passage S5 (see FIG. 6), which will be described later, to mix.

[0035] In this embodiment, the end surface 91a of the root portion 91 of the blade portion 90 abuts against the outer peripheral surface of the bearing member 71. However, the structure of the root portion 91 is not limited to this. FIG. 7(D) is a cross-sectional view showing a variation of the blade portion 90. As shown in FIG. 7(D), the end surface 91b on the inner side in the transverse direction of the root portion 91B is disposed with a gap from the outer peripheral surface of the bearing member 71 and faces the outer peripheral surface of the bearing member 71 in the transverse direction. Even in this configuration, the flange through-hole 81 opens between the root portion 91B and the notch 92 of one blade portion 90 and the root portion 91B and the notch 92 of another blade portion 90 adjacent to the first blade portion 90. As a result, the root portion 91B prevents the fluid F heading toward the flange through-hole 81 from flowing around the axis L around the bearing member 71. Therefore, the fluid F flows smoothly along the base portion 91B without accumulating around the axis L of the bearing member 71. This makes it possible to prevent air bubbles from accumulating around the axis L around the bearing member 71.

[0036] When a gap is provided between the base portion 91 and the bearing member 71, it is preferable that the flange through-hole 81 does not open into this gap. If the flange through-hole 81 opens into the gap, the fluid F will flow through the gap around the axis L, which will cause air bubbles to easily remain around the axis L around the bearing member 71.

[0037] As shown in FIG. 5, a rotor magnet 93 is installed below the flange portion 78. The rotor magnet 93 is a cylindrical permanent magnet. As shown in FIG. 9(A), the rotor magnet 93 includes an annular upper wall portion 94. An insertion hole 94a is formed in the center of the upper wall portion 94, penetrating in the direction of the axis L. The insertion hole 94a is a hole into which the cylindrical portion 71a of the bearing member 71 is inserted, and is formed in a circular shape with a diameter slightly larger than that of the cylindrical portion 71a. A magnet through hole 95 is formed in the upper wall portion 94, penetrating in the direction of the axis L. As shown in FIG. 5, the magnet through hole 95 is formed coaxially with the flange through hole 81 of the flange portion 78 and communicates with the flange through hole 81. This allows the fluid F in the upper space S7 to flow through the opening 80, the flange through hole 81, and the magnet through hole 95 into the rotor magnet 93, i.e., the lower space S8.

[0038] In this manner, passages such as the flange through-hole 81 and the magnet through-hole 95 that communicate between the opening 80 and the lower space S8 are referred to as flange portion communication passages S9. The flange through-hole 81 and the magnet through-hole 95 do not necessarily need to be coaxial as long as they communicate with each other. However, from the viewpoint of smoothing the flow of the fluid F within the flange portion communication passages S9, it is preferable that they at least partially overlap in the direction of the axis L. As shown in FIG. 9(B), a fitting protrusion 96 that protrudes upward is formed in the center of the upper wall portion 94. As shown in FIG. 9(A), a pair of fitting protrusions 96 are formed and are fitted into the fitting holes 82 of the flange portion 78 from below to above. This fitting, along with the support of the snap ring 74, allows the rotor magnet 93 to be integrated with the bearing member 71 and to rotate together with the bearing member 71 about the axis L. 9(B), the rotor magnet 93 is formed with cylindrical portions 97 extending in the direction of the axis L from the outer edge of the upper wall portion 94. The cylindrical portions 97 are spaced apart in the intersecting direction and cover parts of the bearing member 71 in the circumferential direction.

[0039] Next, the operation of the centrifugal pump 1 will be described. First, in the assembled state shown in FIG. 2, when a current is passed through the coil portion 63, the coil 66 is excited, generating a magnetic force around the rotor housing portion 34. This magnetic force acts on the rotor magnet 93 of the rotating blade member 70, causing the rotating blade member 70 to rotate around the axis of the shaft member 33. This generates a flow of fluid F within the main body case 20, and as shown in FIG. 3, the fluid F within the suction side joint 11 flows into the fluid introduction flow path S1 through the suction port 43. The fluid F then flows toward the center of the main body case 20 and into the blade housing space S2 through the flow path opening 52 of the blade case 50. The fluid F that has flowed into the blade housing space S2 flows around the axis (counterclockwise in FIG. 4) as shown in FIG. 4, and flows out to the discharge side joint 12 through the discharge port 44.

[0040] In the centrifugal pump 1, air bubbles may be generated in the minute space S3 between the shaft member 33 and the bearing member 71. In this case, so-called dry sliding occurs, in which the shaft member 33 and the bearing member 71 directly slide against each other, and wear may occur at the contact points between the shaft member 33 and the bearing member 71. For this reason, it is necessary to remove the air bubbles from the perspective of improving the durability of the centrifugal pump 1. However, within the impeller housing space S2, in the upper space S7 where the impeller portion 90 is located, the rotation of the impeller portion 90 tends to push the fluid F outward in the intersecting direction and press it against the inner wall surface of the vertical wall 53 of the impeller case 50. Therefore, as shown in FIG. 5 , the inner wall surface side of the vertical wall 53 of the upper space S7 tends to become a high-pressure portion (hereinafter, may be referred to as high-pressure portion α).

[0041] On the other hand, because the rotation of the blade portion 90 pushes the fluid F outward in the intersecting direction, the upper space S7 on the shaft member 33 side is likely to become a low-pressure area (hereinafter, sometimes referred to as the low-pressure area β). In the lower space S8 where the blade portion 90 is not located, the above-described pushing-out of the fluid F by the blade portion 90 is small, so the pressure tends to be intermediate between the high-pressure area α and the low-pressure area β (hereinafter, sometimes referred to as the medium-pressure area γ). Therefore, in the blade housing space S2, in addition to the above-described flow of the fluid F from the suction port 43 toward the discharge port 44, a flow of the fluid F also occurs from the high-pressure area α toward the medium-pressure area γ and then toward the low-pressure area β. Therefore, it is difficult to expel bubbles generated in the microspace S3 against this flow.

[0042] Furthermore, when air bubbles are generated in the minute space S3, it is also conceivable to discharge the air bubbles from the upper end of the bearing member 71. However, for example, when the fluid F passes through a long distance from the lower end to the upper end of the minute space S3, frictional resistance during the passage tends to make it difficult to discharge the air bubbles. Furthermore, since the upper end of the bearing member 71 (the upper end of the protrusion 75) is often close to the inner wall surface of the top wall 41 of the upper main body case 40, it is difficult to secure sufficient space, and this tends to make it even more difficult to discharge the air bubbles from the upper end of the bearing member 71.

[0043] It is also possible to flow fluid F into the minute space S3 from the upper end side of the bearing member 71 to fill the minute space S3 with fluid F, but as mentioned above, it is difficult to secure sufficient space between the upper end of the bearing member 71 and the inner wall surface of the top wall 41 of the upper main body case 40, so it is not easy to flow fluid F into the minute space S3 from above.

[0044] Therefore, in this embodiment, by configuring the rotary vane member 70 as described above, even if air bubbles are generated in the minute space S3, the air bubbles can be easily discharged to the outside of the main body case 20.

[0045] Specifically, as shown in FIG. 5 , a flange portion communicating passage S9 is formed in the rotary vane member 70. Therefore, a flow of fluid F is generated from the high-pressure portion α of the upper space S7 through the flange portion communicating passage S9 toward the lower space S8, which is the medium-pressure portion γ. This flow is specifically referred to as flow F1. This flow F1 reduces the pressure in the upper space S7, slightly increasing the pressure in the lower space S8. From this slightly increased pressure, a flow of fluid F is generated between the outer circumferential surface of the rotor magnet 93 and the inner circumferential surface of the rotor accommodating portion 34 without passing through the flange portion communicating passage S9. This flow is specifically referred to as flow F2. In other words, the provision of the flange portion communicating passage S9 facilitates separation of the flow F1 and the flow F2, making it easier to prevent the flow F1 and the flow F2 from crossing each other. Therefore, even if air bubbles are generated in the minute space S3, the air bubbles can be discharged, for example, from the other-side communicating passage S6 to the lower space S8 and then easily discharged to the outside of the main body case 20 by the flow F2.

[0046] Furthermore, in this embodiment, as shown in FIG. 6 , the bearing member 71 is provided with a bearing portion communication passage S5 that penetrates the wall surface of the bearing member 71 and connects the miniaturized space S3 to the upper space S7. This generates a flow of fluid F from the miniaturized space S3 through the bearing portion communication passage S5 toward the upper space S7. This flow is specifically referred to as flow F3. Therefore, bubbles generated in the miniaturized space S3 can be easily discharged to the outside via flow F3. This configuration allows the fluid F to flow out of the miniaturized space S3 along its entire length, rather than continuously from the bottom to the top, within the miniaturized space S3. This suppresses a decrease in flow rate due to wear resistance between the fluid F and the bearing member 71 or the shaft member 33, thereby facilitating the discharge of bubbles from the miniaturized space S3. Therefore, even when the bearing member 71 and the shaft member 33 are relatively long in the axial direction L, bubbles can be easily discharged.

[0047] Furthermore, in this embodiment, as shown in FIG. 6, a one-side communication passage S4 that connects the mini-space S3 and the upper space S7 is formed at the upper end of the bearing member 71. Therefore, even if the space between the upper end of the bearing member 71 and the inner wall surface of the upper main body case 40 is small, the fluid F can flow smoothly through the fluid introduction passage S1, the passage opening 52, the one-side communication passage S4, and the mini-space S3 in that order. The fluid F can also flow smoothly through the upper space S7, the one-side communication passage S4, and the mini-space S3 in that order. This allows the mini-space S3 to be filled with the fluid F. The fluid F in the mini-space S3 can also be discharged from a predetermined portion, such as the bearing portion communication passage S5, that communicates with the upper space S7 or the lower space S8. This flow of the fluid F is referred to as flow F4.

[0048] According to the above configuration, it is possible to provide a centrifugal pump 1 that can easily discharge air inside the main body case 20 (case) to the outside of the main body case 20, thereby suppressing dry sliding.

[0049] In the present embodiment, the flange portion communicating passage S9 is configured by the flange through hole 81 and the magnet through hole 95, but the configuration of the flange portion communicating passage S9 is not limited to this. For example, as shown in FIG. 5 , gaps may be formed between the flange portion 78, the rotor magnet 93, and the bearing member 71. The gap between the flange portion 78 and the rotor magnet 93 may be defined as a first gap S10, and the gap between the bearing member 71 and the rotor magnet 93 may be defined as a second gap S11, with the flange through hole 81, the first gap S10, and the second gap S11 constituting the flange portion communicating passage S9. Note that the flange portion communicating passage S9 may be formed by combining some or all of the flange through hole 81, the magnet through hole 95, the first gap S10, and the second gap S11, as long as the configuration allows communication between the upper space S7 and the lower space S8.

[0050] For example, if the flange portion communicating passage S9 is configured with the flange through hole 81 and the magnet through hole 95 as in this embodiment, the fluid F passing through the flange portion communicating passage S9 can be more easily isolated from the fluid F flowing in other parts of the main body case 20, and the flow F1 and the flow F2 can be more easily separated. This configuration is therefore useful from the perspective of smoothing the flow of the fluid F. On the other hand, if the flange portion communicating passage S9 is configured with the flange through hole 81 and the first and second gaps S10 and S11, there is no need to drill a hole in the rotor magnet 93. This eliminates the need for the effort of drilling the hole and then aligning the hole with the flange through hole 81, thereby simplifying the configuration of the flange portion communicating passage S9. This configuration is therefore useful from a cost perspective.

[0051] The configuration of the flange portion communicating passage S9 can be further diversified. FIGS. 10A to 10C are diagrams showing variations of the rotary vane member 70. For example, in this embodiment, the flange through-hole 81 is defined as a through-hole penetrating from one flange surface 79 of the flange portion 78 in the axial direction L. However, the configuration of the flange through-hole 81 is not limited to this. As shown in FIG. 10A, a groove 78a extending in the axial direction L may be formed in the outer peripheral surface of the flange portion 78 of the rotary vane member 70, and the interior of this groove 78a may serve as the flange through-hole 81. As shown in FIG. 10B, a D-cut surface 78b formed by cutting out an arc-shaped portion may be formed in the outer peripheral surface of the flange portion 78 of the rotary vane member 70, and the portion between this D-cut surface 78b and the inner peripheral surface of the rotor accommodating portion 34 of the main body case 20 may serve as the flange through-hole 81. As shown in FIG. 10C, the magnet through-hole 95 may be omitted. Specifically, a large-diameter portion 71b may be formed in part of the cylindrical portion 71a of the bearing member 71, the large-diameter portion 71b extending down to the flange through-hole 81', and the flange through-hole 81' may be formed penetrating this large-diameter portion 71b, with this flange through-hole 81' serving as the flange portion communicating passage S9. In addition, in this embodiment, the second gap S11 is formed by making the inner diameter of the insertion hole 94a of the rotor magnet 93 larger than the outer diameter of the cylindrical portion 71a of the bearing member 71, but the configuration of the second gap S11 is not limited to this. For example, although not shown, a D-cut surface may be formed on the outer circumferential surface of the cylindrical portion 71a of the bearing member 71, and the space between this D-cut surface and the insertion hole 94a may serve as the second gap S11.

[0052] 7B, when the end surface 91a of the base portion 91 abuts against the outer peripheral surface of the bearing member 71, the blade portion 90 and the outer peripheral surface of the bearing member 71 are continuous with each other in the transverse direction without any gaps. Therefore, compared to a configuration in which there is a gap between the blade portion 90 and the outer peripheral surface of the bearing member 71, there is no room for air bubbles to remain in the space between the blade portion 90 and the bearing member 71. Furthermore, according to this configuration, the bearing portion communication passage S5 is provided between adjacent base portions 91. Therefore, the fluid F discharged from the bearing portion communication passage S5 is prevented from flowing around the axis L by the base portions 91 and flows smoothly in the transverse direction along the base portions 91. Therefore, the fluid F discharged from the bearing portion communication passage S5 flows smoothly in the transverse direction along the blade portion 90 without accumulating around the bearing member 71. This flow allows air bubbles to be discharged to the outside without being trapped around the bearing member 71. 7(D), even when end face 91b of base portion 91B faces the outer peripheral surface of the bearing portion, fluid F discharged from bearing portion communication passage S5 (not shown in FIG. 7D) is prevented from flowing around the axis by base portion 91B, and flows smoothly in the intersecting direction along base portion 91B. Therefore, fluid F discharged from bearing portion communication passage S5 can flow smoothly in the intersecting direction along blade portion 90.

[0053] 8A, in this embodiment, the opening 80 of the flange portion communicating passage S9 and one opening of the bearing portion communicating passage S5 are located in different regions R. This makes it easy to separate the fluid F flowing from the upper space S7 to the lower space S8 via the flange portion communicating passage S9 from the fluid F flowing from the bearing portion communicating passage S5 to the outside of the main body case 20 via the upper space S7. This makes it difficult for the flow F1 shown in FIG. 5 and the flow F3 shown in FIG. 6 to intersect. This prevents air bubbles discharged from the bearing portion communicating passage S5 by the flow F3 from being re-introduced by the flow F1 into the lower space S8 via the flange portion communicating passage S9, allowing the air bubbles to be efficiently discharged outside the main body case 20.

[0054] In addition, in this embodiment, as shown in FIG. 5, the lower end of the one-side communicating passage S4 is located below the upper end of the flow path opening 52, so that the flow path area of ​​the one-side communicating passage S4 can be easily ensured, and the fluid F can be efficiently circulated toward the minute space S3 via the one-side communicating passage S4.

[0055] In this embodiment, the upper end of the bearing member 71 is located above (not shown) or below (see FIG. 3 ) the upper end of the flow path opening 52. According to this configuration, when the upper end of the bearing member 71 is located above the upper end of the flow path opening 52, the upper end of the bearing member 71 protrudes into the fluid introduction flow path S1 and is close to the top wall 41 of the main body case 20. Therefore, even if the bearing member 71 is unintentionally displaced in the direction of the axis L, the upper end of the bearing member 71 can be easily brought into contact with the top wall 41, thereby making it easier to suppress the displacement. Therefore, rattle of the bearing member 71 in the direction of the axis L can be suppressed. Furthermore, when the upper end of the bearing member 71 is located below the upper end of the flow path opening 52, the upper end of the bearing member 71 does not protrude toward the fluid introduction flow path S1. This makes it less likely for the shaft member 33 and the bearing member 71 to obstruct the flow of the fluid F in the fluid introduction flow path S1. Therefore, a sufficient flow path area for the fluid F flowing from the fluid introduction flow path S1 toward the flow path opening 52 can be ensured, and the flow of the fluid F in the fluid introduction flow path S1 and the flow F4 can be made smooth.

[0056] 4, in this embodiment, the one-side communicating passage S4 is configured as a recess 71A that opens to the upper end of the bearing member 71. Therefore, compared to a structure in which the one-side communicating passage S4 is formed by providing a through-hole or the like in the bearing member 71, for example, it is easier to ensure the flow path area of ​​the one-side communicating passage S4, and therefore the pressure loss of the fluid F flowing through the one-side communicating passage S4 can be reduced.

[0057] 4, the bearing member 71 is provided with an annular space 71B that extends around the axis L and connects the one-side communicating passage S4 to the minute space S3. With this configuration, the fluid F that flows from the one-side communicating passage S1 to the minute space S3 flows from the entire circumference around the axis L of the bearing member 71 via the annular space 71B. This makes it possible to ensure a sufficient flow rate of the fluid F that flows from the one-side communicating passage S4 to the minute space S3.

[0058] 6, in this embodiment, an other-side communication passage S6 that communicates the miniscule space S3 and the lower space S8 is formed between the lower end surface 76 of the rotary vane member 70 and the fixed member 32. This allows the fluid F to easily flow from the lower space S8 into the miniscule space S3, making it easy to fill the miniscule space S3 with the fluid F. This also makes it easy to generate the flow F3 described above, so the fluid F that has flowed into the miniscule space S3 can be easily discharged from the bearing communication passage S5 described above, etc.

[0059] In this embodiment, the other-side communication passage S6 is defined by a slit 77 formed in the lower end surface 76 of the bearing member 71, but the configuration of the other-side communication passage S6 is not limited to this. FIG. 11 is a plan view of a fixed member 32' according to a modified example, and FIG. 11(B) is a cross-sectional view taken along the line FF in FIG. 11(A). The fixed member 32' shown in FIG. 11(A) corresponds to the fixed member 32 described above. The upper end surface 32a of the fixed member 32' faces the lower end surface 76 of the bearing member 71. A slit-shaped recessed groove 32b (second recessed portion) is formed in the upper end surface 32a, opening upward and extending in the intersecting direction. A plurality of recessed grooves 32b (three in this modified example) are formed at intervals around the axis L. The other-side communication passage S6 is defined by these recessed grooves 32b.

[0060] Thus, according to the above-described embodiment and modified examples, at least a portion of the other-side communication passage S6 is formed by the slit 77 (first recessed portion) opening in the lower end surface 76, or the recessed groove 32b (second recessed portion) opening in the fixed member 32'. Furthermore, the structure of the other-side communication passage S6 is not limited to this, and for example, the other-side communication passage S6 may be formed by providing a slit or hole in the thrust bearing 72 arranged between the fixed member 32 and the bearing member 71.

[0061] While the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited thereto, and design changes within the spirit and scope of the present invention are also encompassed within the scope of the present invention. FIG. 12 is a longitudinal cross-sectional view of a rotary vane member 70A according to a second embodiment, taken along the axis L. The rotary vane member 70A includes a sliding contact portion 100 and a large inner diameter portion 101 on the inner peripheral surface of the bearing member 71. The sliding contact portion 100 is a portion that can slide against the outer peripheral surface of the shaft member 33. The sliding contact portion 100 has an inner diameter substantially the same as the outer diameter of the shaft member 33 and is formed above and below the large inner diameter portion 101. The large inner diameter portion 101 has an inner diameter larger than that of the sliding contact portion 100 and constitutes a flow rate increasing portion that enlarges the minute space S3 between the bearing member 33 and the large inner diameter portion 101, thereby easily increasing the flow rate of the fluid F. A bearing communication passage S5 penetrates the large inner diameter portion 101. With this configuration, the flow rate increasing portion increases the flow rate of the fluid F in the minute space S3. The fluid F in the minute space S3 and the fluid F in the blade housing space S2 can be circulated via the flow rate increasing section and the bearing section communication passage S5. This makes it easier to suppress dry sliding between the shaft member 33 and the bearing member 71.

[0062] The structure of the flow rate increasing portion is not limited to this, and various other structures are possible. FIG. 13(A) is a plan view of a rotary vane member 70B according to a first modification of the second embodiment, FIG. 13(B) is an enlarged view of a main portion of FIG. 13(A), and FIG. 13(C) is a cross-sectional view taken along line GG in FIG. 13(A). As shown in FIGS. 13(A) and 13(B), the rotary vane member 70B includes a flow rate increasing groove 102 on the inner circumferential surface of the bearing member 71. As shown in FIG. 13(B), the flow rate increasing groove 102 is recessed outward in the transverse direction, and as shown in FIG. 13(C), it extends in the axial direction L from the upper end to the lower end of the inner circumferential surface of the bearing member 71. In the first modification of the second embodiment, the interior of the flow rate increasing groove 102 has the same function as the flow rate increasing portion described above. This configuration allows the flow rate increasing portion to be easily formed by forming a linear groove on the inner circumferential surface of the bearing member 71.

[0063] Furthermore, a flow rate increasing portion can be formed by modifying the shape of the shaft member 33. FIG. 14(A) is a plan view of a shaft member 33A according to a second modified example of the second embodiment, and FIG. 14(B) is a side view of the shaft member 33A according to the second modified example of the second embodiment. As shown in FIG. 14(A), a D-cut surface portion 33A-1 is formed by cutting out an arc-shaped portion on a part of the outer circumferential surface of the shaft member 33A. The D-cut surface portion 33A-1 extends in the direction of the axis L from the upper end to the lower end of the shaft member 33A. With this configuration, when the shaft member 33A is inserted into the center of the bearing member 71, a gap is formed between the D-cut surface portion 33A-1 and the inner circumferential surface of the bearing member 71, and this gap can serve as a flow rate increasing portion.

[0064] In the above-described embodiment and modified examples, the flange portion communicating passage S9, the bearing portion communicating passage S5, the one-side communicating passage S4, and the other-side communicating passage S6 are formed in the rotary vane member 70. However, these communicating passages may be omitted as appropriate, or their combination may be changed. FIG. 15(A) is a plan view of a rotary vane member 70D according to a third embodiment, FIG. 15(B) is a side view of the rotary vane member 70D according to the third embodiment, and FIG. 15(C) is a cross-sectional view taken along line HH in FIG. 15(A). As shown in FIGS. 15(A) and 15(B), the rotary vane member 70D includes a bearing member 71D. The bearing member 71D corresponds to the bearing member 71 described above. As shown in FIG. 15(C), the upper end of the bearing member 71D is located below the upper end of the blade portion 90. The upper end of this bearing member 71D does not include a protrusion 75 or one-side communicating passage S4.

[0065] Even in this configuration, for example, by providing at least the flange portion communicating passage S9, the upper space S7 and the lower space S8 can be connected to each other via the flange portion communicating passage S9, thereby generating the flows F1 and F2 (see FIG. 5) of the fluid F. This makes it possible to provide a centrifugal pump 1 that can suppress dry sliding by facilitating the discharge of air from the main body case 20 to the outside of the main body case 20. Furthermore, in the configuration of the third embodiment, by providing at least the bearing portion communicating passage S5, air bubbles in the minispace S3 can be easily discharged from the bearing portion communicating passage S5 to the upper space S7. Furthermore, in the configuration of the third embodiment, by providing at least the flange portion communicating passage S9 and the bearing portion communicating passage S5, the flows F1, F2, and F3 can be generated, making it even easier to discharge air bubbles from the minispace S3.

[0066] Although not shown, it is also possible to omit the flange portion communicating passage S9, for example. Even in this configuration, for example, by providing at least the bearing portion communicating passage S5, air bubbles in the miniature space S3 can be easily discharged from the bearing portion communicating passage S5 to the upper space S7. Furthermore, in a configuration in which the flange portion communicating passage S9 is omitted, by providing at least the one-side communicating passage S4, the fluid F can be smoothly flowed through the fluid introduction passage S1, the passage opening 52, the one-side communicating passage S4, and the miniature space S3 in that order. Furthermore, the fluid F can be smoothly flowed through the upper space S7, the one-side communicating passage S4, and the miniature space S3 in that order. This allows the miniature space S3 to be filled with the fluid F.

[0067] In this case, by providing a hole in any one of the bearing members 71 that communicates with the miniature space S3 and the blade housing space S2, a flow F4 (see FIG. 6) can be generated, and air bubbles in the miniature space S3 can be discharged to the outside. Furthermore, in a configuration in which the flange portion communicating passage S9 is omitted, by providing at least the bearing portion communicating passage S5 and the one-side communicating passage S4, a flow F4 (see FIG. 6) can be generated that flows through the fluid introduction passage S1, the passage opening 52, the one-side communicating passage S4, the miniature space S3, and the bearing portion communicating passage S5 in this order. This flow F4 can then discharge air bubbles in the miniature space S3 to the outside. [Explanation of symbols]

[0068] S3 Microspace S4 One-side communication passage S5 Bearing communication passage S7 upper space (one side space) S8 Lower space (other space) S9 Flange connecting passage 1. Centrifugal pump 20 Main unit case 33 Shaft member 43 Intake port 44 Discharge port 70 Rotating blade member 71 Bearing materials 78 Flange 79 One side flange surface 80 Opening 90 Wing

Claims

1. A centrifugal pump comprising: a rotary vane member that rotates around the axis of a shaft member; a main body case that houses the rotary vane member; and a suction port and a discharge port that communicate with the inside and outside of the main body case, The rotary vane member includes a cylindrical bearing portion into which the shaft member is inserted, a flange portion extending radially from the bearing portion, a plurality of vane portions erected on one flange surface that is a surface on one axial side of the flange portion and extending radially in the radial direction, and a minute space provided between the shaft member and the bearing portion and communicating with the inside of the main body case, a one-side space located on one side of the flange portion in the axial direction is provided within the main body case, a bearing portion communicating passage penetrating a wall surface of the bearing portion on one axial side of the one-side flange surface and communicating the minute space with the one-side space.

2. the blade portion includes a root portion extending in the radial direction from an end surface that abuts against or faces an outer circumferential surface of the bearing portion, 2. The centrifugal pump according to claim 1, wherein the bearing portion communication passage is provided between adjacent ones of the base portions.

3. a second space located on the second axial side of the flange portion is provided in the main body case, a fixing member that fixes an end portion of the shaft member on the other axial side is provided in the other space, the other axial end of the bearing portion has a other end surface facing the fixed member, 2. The centrifugal pump according to claim 1, wherein an other-side communication passage is provided between the other-side end surface and the fixed member, the other-side communication passage communicating the minute space with the other-side space.

4. 4. The centrifugal pump according to claim 3, wherein at least a portion of the second-side communication passage is formed by a first recessed portion that opens into the second-side end face.

5. 4. The centrifugal pump according to claim 3, wherein at least a portion of the other-side communication passage is formed by a second recessed portion that opens into the fixed member.

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