pump

Abstract

To restrain cavitation from occurring.SOLUTION: A pump comprises an impeller 9, and a driving part. The impeller 9 comprises a plurality of plate-like blade parts 93 opposed in a rotation direction. The driving part 3 rotates the impeller 9 to make liquid flow. The impeller 9 comprises a flow passage 96. The flow passage 96 is formed between the plurality of blade parts 93. In the flow passage 96, the liquid flows toward an outflow port 962 located in an outer edge part 95 of the impeller 9, from an inflow port 961 located in an inner edge part 94 of the impeller 9. The flow passage 96 comprises a throttling part 963 having a cross-sectional area smaller than a cross-sectional area of the inflow port 961 and a cross-sectional area of the outflow port 962.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure generally relates to pumps, and more particularly to pumps equipped with impellers.

Background Art

[0002] The pump impeller described in Patent Document 1 includes a first impeller body, a second impeller body, a discharge flow path, and a collar. When the pump impeller described in Patent Document 1 is mounted on a pump and operates, a liquid is drawn from the inlet hole of the first impeller body by centrifugal force and flows outward through the discharge flow path. In the pump impeller described in Patent Document 1, the cross-sectional area of the discharge flow path decreases as it approaches the outer end from the inner end.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a pump impeller (pump) as described in Patent Document 1, cavitation may occur in the discharge flow path.

[0005] In view of the above reasons, the present disclosure is made, and an object thereof is to provide a pump capable of suppressing the occurrence of cavitation.

Means for Solving the Problems

[0006] A pump according to one aspect of the present disclosure comprises an impeller and a drive unit. The impeller has a plurality of plate-shaped blades facing each other in the direction of rotation. The drive unit rotates the impeller to cause a liquid to flow. The impeller has a flow path. The flow path is formed between the plurality of blades. In the flow path, the liquid flows from an inlet located on the inner edge of the impeller to an outlet located on the outer edge of the impeller. Between the inlet and the outlet, The flow path is formed without narrowing its width. The device has a constricted portion with a cross-sectional area smaller than the cross-sectional area of ​​the inlet and the cross-sectional area of ​​the outlet. The height of the plurality of vanes in the constricted portion is lower than the height of the plurality of vanes in the inlet. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide a pump capable of suppressing the occurrence of cavitation. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view of the pump according to Embodiment 1. [Figure 2] Figure 2 is an enlarged cross-sectional view of the main part of the pump mentioned above. [Figure 3] Figure 3 is a perspective view of the positioning member of the pump mentioned above. [Figure 4] Figure 4 is a perspective view of the positioning member mentioned above, viewed from a different angle. [Figure 5] Figure 5 is a schematic diagram of the main components of the pump mentioned above. [Figure 6] Figure 6 is a perspective view of the main part of the impeller of the pump mentioned above. [Figure 7] Figure 7 is a plan view of the main part of the impeller related to the same. [Figure 8] Figure 8 is a cross-sectional view of the main part of the impeller related to the above. [Figure 9] Figure 9 is a graph showing the relationship between the cross-sectional area and position in the flow path of the impeller mentioned above. [Figure 10] Figure 10 is a perspective view of the positioning member of the pump according to the first modified example. [Figure 11] Figure 11 is a schematic diagram of the main parts of the pump according to the second modified example. [Figure 12] Figure 12 is a perspective view of the positioning member of the pump mentioned above. [Figure 13] Figure 13 is a perspective view of the positioning member mentioned above, viewed from a different angle. [Figure 14] Figure 14 is a perspective view of the positioning member of the pump according to the third modified example. [Figure 15] Figure 15 is a schematic diagram of the main components of the pump mentioned above. [Figure 16] Figure 16 is a schematic diagram of the main parts of the pump according to Embodiment 2. [Modes for carrying out the invention]

[0009] Preferred embodiments of this disclosure will be described in detail below with reference to the drawings. In the embodiments described below, elements common to each other are denoted by the same reference numerals, and redundant descriptions of common elements will be omitted. Each of the embodiments described below is merely one of many embodiments of this disclosure. Each embodiment can be modified in various ways depending on the design, etc., as long as it achieves the objectives of this disclosure.

[0010] The figures described in this disclosure are schematic diagrams, and the ratios of the size and thickness of each component in each figure do not necessarily reflect the actual dimensional ratios. Furthermore, the arrows indicating directions are examples only and are not intended to specify the direction in which pump 1 is used. Also, the arrows indicating directions in the drawings are for illustrative purposes only and do not represent actual objects.

[0011] In this disclosure, "orthogonal (perpendicular)" means not only a state where the angle between two objects is exactly 90°, but also a state where the two objects are approximately orthogonal within a certain margin of error. In other words, the angle between two orthogonal objects falls within a certain margin of error (for example, 10° or less) relative to 90°.

[0012] In the following description, in the exemplification of values such as distance and area, the part described as "below" may mean "less than". That is, in the comparison of two values, whether or not the case where the two values are equal is included can be arbitrarily changed depending on the setting of a reference value or the like, and there is no technical difference between "below" and "less than". Similarly, the part described as "above" may mean "exceeding".

[0013] (Embodiment 1) (1) Outline First, the outline of the pump 1 according to Embodiment 1 will be described with reference to FIGS. 1 and 6.

[0014] As shown in FIG. 1, the pump 1 includes a drive unit 3 and an impeller 9.

[0015] The drive unit 3 rotates the impeller 9 to cause a liquid to flow. Specifically, the drive unit 3 changes a magnetic field to rotate the impeller 9. By the drive unit 3 rotating the impeller 9, the pump 1 sucks a liquid such as water from the suction part 22 into the pump chamber Sp3 and discharges the liquid from the discharge part 24 to the outside of the pump 1.

[0016] The impeller 9 is housed in the pump chamber Sp3. The impeller 9 has a front shroud 91 (first shroud) and a rear shroud 92 (second shroud).

[0017] As shown in FIG. 6, the front shroud 91 is formed in an annular shape. A plurality (13 in the example of FIG. 6) of blade parts 93 are formed on the front shroud 91. In other words, the impeller 9 has a plurality of blade parts 93.

[0018] Each of the plurality of blade parts 93 is formed in a plate shape facing the rotation direction. A plurality (13) of flow paths 96 are formed between the plurality of blade parts 93. In other words, the impeller 9 has a plurality of flow paths 96.

[0019] The flow path 96 is formed between two adjacent blade portions 93. The flow path 96 also extends from the inner edge 94 to the outer edge 95 of the front shroud 91 (impeller 9). When the impeller 9 rotates, liquid flows through the flow path 96 from the inlet 961 located at the inner edge 94 to the outlet 962 located at the outer edge 95. The flow path 96 has a constricted portion 963.

[0020] The throttling section 963 is formed in the flow path 96 between the inlet 961 and the outlet 962. The throttling section 963 has a cross-sectional area smaller than the cross-sectional area of ​​the inlet 961 and the cross-sectional area of ​​the outlet 962.

[0021] Since the cross-sectional area of ​​the throttling section 963 is smaller than the cross-sectional area of ​​the inlet 961 and the outlet 962, the throttling section 963 pressurizes the liquid passing through it. Because the throttling section 963 pressurizes the liquid, the pump 1 of Embodiment 1 can suppress the occurrence of cavitation.

[0022] (2) Details The details of the pump 1 according to Embodiment 1 will be described below with reference to Figures 1 to 9. In the following description, the extension direction D1 of the axis Ax1 of the rotating shaft 6 is defined as the "front-rear direction". Furthermore, the direction from the rotating shaft 6 toward the cylindrical portion 21 of the pump case 2 is defined as "forward", and the direction from the cylindrical portion 21 toward the rotating shaft 6 is defined as "rear".

[0023] Pump 1 is, for example, a pump used underwater. As shown in Figure 1, pump 1 comprises a pump case 2, a drive unit 3, a rotating shaft 6, a bearing 7, a rotor unit 8, an impeller 9, a receiving plate 100, a positioning member 200, an elastic member 300, and a plate 400.

[0024] (2.1) Pump case The pump case 2 has a cylindrical portion 21, an intake portion 22, a base portion 23, and a discharge portion 24.

[0025] The base portion 23 has a bottomed cylindrical shape. The base portion 23 forms a first space Sp1 that houses the impeller 9. The first space Sp1 is at least a part of the pump chamber Sp3. That is, the base portion 23 (pump case 2) forms at least a part of the pump chamber Sp3. The base portion 23 has a first opening 231 and a second opening 232.

[0026] The first opening 231 is formed at the bottom of the base 23 along the extension direction D1 (front-rear direction) of the rotation axis 6. In Embodiment 1, the shape of the first opening 231 is circular in a plan view along the extension direction D1. However, the shape of the first opening 231 is not limited to a circular shape, and the shape of the first opening 231 may be, for example, a polygon.

[0027] The second opening 232 is formed on the side circumference of the base 23. The shape of the second opening 232 is circular in a plan view along the radial direction D2. However, the shape of the second opening 232 is not limited to a circular shape, and may be polygonal, for example. The radial direction D2 is perpendicular to the extension direction D1 of the rotation axis 6 and is along the diameter of a virtual circle centered on the axis Ax1 of the rotation axis 6.

[0028] The suction portion 22 protrudes forward from the edge of the first opening 231 of the base portion 23. The shape of the suction portion 22 is cylindrical. However, the shape of the suction portion 22 is not limited to cylindrical, and may be, for example, a cylindrical shape with a polygonal cross-section. When the impeller 9 is operating, the suction portion 22 draws in liquid such as water from outside the pump 1.

[0029] The discharge section 24 protrudes from the side circumference of the base section 23. The shape of the discharge section 24 in Embodiment 1 is cylindrical. However, the shape of the discharge section 24 is not limited to cylindrical, and for example, it may be a cylindrical shape with a polygonal cross-section. The internal space of the discharge section 24 and the first space Sp1 are connected through the second opening 232. When the impeller 9 is operating, the discharge section 24 discharges the liquid in the pump chamber Sp3 (first space Sp1) to the outside of the pump 1.

[0030] The cylindrical portion 21 is supported by the base portion 23 so as to be located in front of the rotating shaft 6 in the extension direction D1 and inside the inner edge portion 921 of the rear shroud 92 in the radial direction D2. The cylindrical portion 21 is formed in the shape of a bottomed cylinder. As shown in Figure 2, the cylindrical portion 21 has a bottom portion 211 and a side circumference portion 212. The shape of the bottom portion 211 is circular. The side circumference portion 212 protrudes rearward from the edge of the bottom portion 211. The shape of the side circumference portion 212 is cylindrical. Note that the shape of the cylindrical portion 21 is not limited to a bottomed cylinder, but may be a bottomed rectangular cylinder, a bottomed elliptical cylinder, or a bottomed cylinder with a part of the side circumference portion 212 missing. The cylindrical portion 21, which is part of the pump case 2, is formed so that the first end portion 61 (one end) of the rotating shaft 6 is inserted into it.

[0031] (2.2) Drive Unit The drive unit 3 shown in Figure 1 rotates the impeller 9 around the rotating shaft 6 as the center of rotation to cause the liquid to flow. The drive unit 3 includes a molded part 4 and a separating plate 5.

[0032] (2.2.1) Molded section The molded section 4 is formed by resin molding of each part necessary for driving the rotor section 8. The shape of the molded section 4 is a bottomed cylindrical shape. The molded section 4 forms a second space Sp2 that houses the rotor section 8. The second space Sp2 is at least a part of the pump chamber Sp3. That is, the molded section 4 (drive section 3) forms at least a part of the pump chamber Sp3.

[0033] The molded portion 4 has a bottom portion 45 and a side circumference portion 46. The bottom portion 45 is circular in shape. The side circumference portion 46 protrudes forward from the edge of the bottom portion 45. The side circumference portion 46 is cylindrical in shape. However, the shape of the bottom portion 45 is not limited to a circular shape, and may be polygonal, for example. The shape of the side circumference portion 46 is not limited to a cylindrical shape, and may be rectangular, for example.

[0034] The molded section 4 includes a stator having a plurality of teeth 41 and a plurality of coils 42, a control section 43, and a connecting section 44. In the following description, each of the plurality of teeth 41 may be referred to as "teeth 41," and each of the plurality of coils 42 may be referred to as "coil 42."

[0035] The connection portion 44 is exposed from the bottom portion 45 of the molded portion 4. The connection portion 44 electrically connects the control unit 43 and the coils 42 to an external device such as a power supply that supplies power to the control unit 43 and the coils 42.

[0036] Multiple teeth 41 and multiple coils 42 are provided on the side circumference 46. The coils 42 are wound around the teeth 41. A magnetic field is generated when the coils 42 are energized.

[0037] The control unit 43 is located at the bottom 45. The control unit 43 changes the magnetic field by controlling the energization of multiple coils 42. More specifically, the control unit 43 changes the magnetic field so that the rotor unit 8 rotates by controlling the energization of multiple coils 42.

[0038] (2.2.2) Separation plate The separation plate 5 covers the front surface of the bottom 45 of the molded section 4, and the front and inner surfaces of the side periphery 46. The separation plate 5 is positioned between the molded section 4 and the pump chamber Sp3. In other words, the separation plate 5 separates the molded section 4 and the pump chamber Sp3. By covering the front surface of the bottom 45 of the molded section 4, and the front and inner surfaces of the side periphery 46, the separation plate 5 prevents water from entering the interior of the molded section 4 from the pump chamber Sp3.

[0039] The separation plate 5 has a bottom portion 51, a side circumference portion 52, a flange portion 53, and a cylindrical portion 54. The bottom portion 51 covers the front surface of the bottom portion 45 of the mold portion 4. The bottom portion 51 is circular in shape. The side circumference portion 52 protrudes forward from the edge of the bottom portion 51. The side circumference portion 52 is cylindrical in shape. The side circumference portion 52 covers the inner surface of the side circumference portion 46 of the mold portion 4. The flange portion 53 protrudes radially D2 from the front end of the side circumference portion 52. The flange portion 53 is annular in shape. The flange portion 53 covers the front surface of the side circumference portion 46 of the mold portion 4.

[0040] The cylindrical portion 54 protrudes forward from the center of the bottom portion 51. The cylindrical portion 54 has a cylindrical shape. The second end portion 62 of the rotating shaft 6, which will be described later, is inserted into the cylindrical portion 54.

[0041] (2.3) Rotation axis The rotating shaft 6 is located inside the pump chamber Sp3. The rotating shaft 6 is made of, for example, ceramic. As shown in Figure 2, the rotating shaft 6 has a base 60, a first end 61, and a second end 62.

[0042] The base 60 is cylindrical in shape. However, the base 60 may also be cylindrical. The axis Ax1 of the rotation shaft 6 is the center of the base 60.

[0043] The first end portion 61 protrudes forward from the front end of the base portion 60. The shape of the first end portion 61 is a semicircular columnar shape in cross-section. The shape of the first end portion 61 may also be a polygonal columnar shape or an elliptical columnar shape. The first end portion 61 is one end of the rotating shaft 6 and is inserted into the cylindrical portion 21, which is part of the pump case 2. In Embodiment 1, the first end portion 61 is inserted into the cylindrical portion 21, which is part of the pump case 2, via a positioning member 200.

[0044] The second end portion 62 protrudes rearward from the rear end of the base portion 60. The shape of the second end portion 62 is a semicircular columnar shape in cross-section. However, the shape of the second end portion 62 may be a polygonal columnar shape or an elliptical columnar shape. The second end portion 62 is the other end of the rotating shaft 6 and is inserted into the cylindrical portion 54, which is part of the separation plate 5.

[0045] (2.4) Bearings The bearing 7 is located between the plate 400 and the receiving plate 100 in the extension direction D1. The bearing 7 has a cylindrical shape. A rotating shaft 6 passes through the bearing 7. The bearing 7 is configured to be movable between the plate 400 and the receiving plate 100 along the extension direction D1.

[0046] The bearing 7 in Embodiment 1 is provided on the rotor portion 8 so as to operate integrally with the rotor portion 8 and rotates around the base portion 60 of the rotating shaft 6. The bearing 7 is made of a resin mixed with a carbon material such as graphite. The bearing 7 has an opposing surface 71 that faces the receiving plate 100 in the extension direction D1. The normal of the opposing surface 71 is along the extension direction D1.

[0047] (2.5) Rotor section As shown in Figure 1, the rotor portion 8 includes a base portion 81, a magnet 82 having multiple magnetic poles, a first connecting portion 83, and a second connecting portion 84.

[0048] The base 81 is cylindrical in shape. The base 81 holds the magnet 82. The magnet 82 is a permanent magnet, such as a neodymium magnet.

[0049] The first connecting portion 83 has a cylindrical shape. In a plan view along the extension direction D1, the first connecting portion 83 surrounds the receiving plate 100, the positioning member 200, and the cylindrical portion 21 of the pump case 2. A part of the outer circumferential surface of the first connecting portion 83 is connected to the inner circumferential surface of the front end of the base portion 81. The rear end of the first connecting portion 83 is located behind the front end of the base portion 81, and the front end of the first connecting portion 83 is located in front of the front end of the base portion 81. The front end of the first connecting portion 83 is connected to the inner edge 921 of the rear shroud 92. In other words, the first connecting portion 83 protrudes rearward from the inner edge 921 of the rear shroud 92.

[0050] The second connecting portion 84 protrudes rearward from the inner circumferential surface of the rear end of the first connecting portion 83. The shape of the second connecting portion 84 is cylindrical. The diameter of the inner circumferential surface of the second connecting portion 84 is approximately the same as the diameter of the outer circumferential surface of the bearing 7. The second connecting portion 84 and the bearing 7 are connected. Because the second connecting portion 84 and the bearing 7 are connected, the rotor portion 8 and the bearing 7 operate as a single unit.

[0051] The rotor 8 rotates due to the interaction between the magnetic field generated by the current flowing through the multiple coils 42 of the stator and the magnetic field generated by the magnets 82 of the rotor 8.

[0052] (2.6) Receiving plate As shown in Figure 2, the support plate 100 is located in front of the bearing 7. More specifically, the support plate 100 is located between the bearing 7 and the cylindrical portion 21, which is part of the pump case 2, in the extension direction D1. More specifically, the support plate 100 is located between the bearing 7 and the positioning member 200 in the extension direction D1. The first end portion 61 of the rotating shaft 6 passes through the hole 103 in the support plate 100. The shape of the hole 103 is semicircular. The hole 103 is configured so that the support plate 100 does not rotate relative to the rotating shaft 6 (first end portion 61) when the first end portion 61 of the rotating shaft 6 is passed through the hole 103. The support plate 100 is made of, for example, ceramic. The support plate 100 is configured to be movable between the bearing 7 and the positioning member 200 along the extension direction D1.

[0053] The support plate 100 is a circular (annular) flat plate having a hole 103. The front surface 102 and rear surface 101 of the support plate 100 are parallel to each other, and the normals of the front surface 102 and rear surface 101 are along the extension direction D1. The rear surface 101 of the support plate 100 contacts the opposing surface 71 of the bearing 7 when the impeller 9 rotates.

[0054] (2.7) Board The plate 400 is located behind the bearing 7. More specifically, the plate 400 is located between the bearing 7 and the cylindrical portion 54, which is part of the separation plate 5, in the extension direction D1. The second end portion 62 of the rotating shaft 6 passes through the hole 401 in the plate 400. The shape of the hole 401 is semicircular. The hole 401 is configured so that the plate 400 does not rotate relative to the rotating shaft 6 (second end portion 62) when the second end portion 62 of the rotating shaft 6 is passed through the hole 401. The plate 400 is made of, for example, ceramic.

[0055] (2.8) Positioning member The positioning member 200 is located in front of the receiving plate 100. More specifically, the positioning member 200 is located between the receiving plate 100 and the cylindrical portion 21, which is part of the pump case 2, in the extension direction D1. The positioning member 200 of Embodiment 1 is formed in the shape of a bottomed cylinder. As shown in Figures 3 and 4, the positioning member 200 of Embodiment 1 has a side circumference portion 201, a rear surface 202, a circular bottom portion 203, and an edge portion 204.

[0056] The edge portion 204 protrudes forward from the edge of the bottom portion 203. The shape of the edge portion 204 is cylindrical. In a plan view along the extension direction D1, the edge portion 204 surrounds the elastic member 300 (see Figure 2).

[0057] The side circumference portion 201 protrudes rearward from the edge of the bottom portion 203. The side circumference portion 201 has a cylindrical shape with a D-shaped cross-section. As shown in Figure 4, the inner surface of the side circumference portion 201 has a flat surface 205 and a circular surface 206. In the pump 1 of Embodiment 1, the first end portion 61 of the rotating shaft 6 is inserted into the inner surface of the side circumference portion 201, and the inner surface of the side circumference portion 201 and the semicircular outer surface of the first end portion 61 are fitted together. In other words, the positioning member 200 of Embodiment 1 covers the first end portion 61 (one end) of the rotating shaft 6. The positioning member 200 is fixed to the rotating shaft 6 by the fitting of the inner surface of the side circumference portion 201 and the outer surface of the first end portion 61. By fitting the first end portion 61 of the rotating shaft 6 into the positioning member 200, the positioning member 200 can be fixed more firmly to the rotating shaft 6.

[0058] As shown in Figure 2, the rear surface 202 is the flat portion at the rear end of the side circumference 201. The normal to the rear surface 202 is along the extension direction D1. The rear surface 202 contacts the front surface 102 of the receiving plate 100 when the pump 1 is in operation. In other words, when the pump 1 is in operation, the positioning member 200 defines the position of the receiving plate 100 in the extension direction D1.

[0059] The positioning member 200 defines the position of the receiving plate 100 in the extension direction D1, which can suppress contact between the receiving plate 100 and the cylindrical portion 21, for example. Even if the rotating shaft 6 is mounted at an angle to the pump case 2 (cylindrical portion 21), the receiving plate 100 can be prevented from tilting relative to the rotating shaft 6 by preventing contact between the receiving plate 100 and the cylindrical portion 21. By preventing the receiving plate 100 from tilting relative to the rotating shaft 6, the contact between the opposing surface 71 of the bearing 7 and the rear surface 101 of the receiving plate 100 can be stabilized, thereby suppressing the generation of vibration and noise during the operation of the pump 1.

[0060] Furthermore, when the pump 1 is in operation, the rear surface 202 of the positioning member 200 contacts the front surface 102 of the receiving plate 100, thereby defining the intersection angle θ1 (see Figure 5) between the flat surface (rear surface 101) of the receiving plate 100 and the rotating shaft 6. For example, the positioning member 200 defines the intersection angle θ1 between the flat surface of the receiving plate 100 and the rotating shaft 6 by preventing contact between the receiving plate 100 and the cylindrical portion 21. The intersection angle θ1 between the flat surface of the receiving plate 100 and the rotating shaft 6 defined by the positioning member 200 is preferably in the range of 85° to 95°. Moreover, the intersection angle θ1 between the flat surface of the receiving plate 100 and the rotating shaft 6 defined by the positioning member 200 is more preferably in the range of 88° to 92°. By defining the intersection angle θ1 between the rear surface 101 of the receiving plate 100 and the rotating shaft 6, the inclination of the receiving plate 100 with respect to the rotating shaft 6 can be further suppressed.

[0061] Furthermore, the intersection angle θ2 (see Figure 5) between the rear surface 202 of the positioning member 200 and the rotating shaft 6 in Embodiment 1 is 90° (perpendicular). In other words, the positioning member 200 in Embodiment 1 defines the intersection angle θ1 between the flat portion (rear surface 101) of the receiving plate 100 and the rotating shaft 6 as 90° (perpendicular). For example, the positioning member 200 defines the intersection angle θ1 between the flat portion of the receiving plate 100 and the rotating shaft 6 as perpendicular by preventing contact between the receiving plate 100 and the cylindrical portion 21. By defining the intersection angle θ1 between the flat portion of the receiving plate 100 and the rotating shaft 6 as perpendicular, the contact between the opposing surface 71 of the bearing 7 and the rear surface 101 (flat portion) of the receiving plate 100 can be made more stable.

[0062] Furthermore, the positioning member 200 of Embodiment 1 defines the position of the receiving plate 100 such that the rear surface 101 (flat portion) of the receiving plate 100 and the opposing surface 71 of the bearing 7 make surface contact. For example, the positioning member 200 prevents the receiving plate 100 from contacting the cylindrical portion 21, thereby ensuring that the flat portion of the receiving plate 100 and the opposing surface 71 of the bearing 7 make surface contact. Here, "surface contact" as used in this disclosure refers to a state in which surfaces that are parallel to each other or can be considered to be parallel to each other are in contact in a planar manner. By defining the position of the receiving plate 100 such that the rear surface 101 of the receiving plate 100 and the opposing surface 71 of the bearing 7 make surface contact, the generation of vibration and noise during the operation of the pump 1 can be suppressed.

[0063] As shown in Figure 5, in the pump 1 of Embodiment 1, a gap Sp4 is formed between the positioning member 200 and the cylindrical portion 21. More specifically, a gap Sp4 is formed between the side circumference 201 of the positioning member 200 and the side circumference 212 of the cylindrical portion 21. In addition, a gap Sp4 is formed between the bottom 203 of the positioning member 200 and the bottom 211 of the cylindrical portion 21.

[0064] Figure 5 shows the state in which the rotating shaft 6 is assembled at an inclination with respect to the cylindrical portion 21. Even when the rotating shaft 6 is assembled at an inclination with respect to the cylindrical portion 21, a gap Sp4 exists between the positioning member 200 and the cylindrical portion 21, causing the positioning member 200 to tilt with respect to the cylindrical portion 21 according to the inclination angle of the rotating shaft 6. By tilting the positioning member 200 with respect to the cylindrical portion 21 according to the inclination angle of the rotating shaft 6, the intersection angle θ2 between the rear surface 202 of the positioning member 200 and the rotating shaft 6 is kept perpendicular.

[0065] By maintaining a vertical intersection angle θ2 between the rear surface 202 of the positioning member 200 and the rotation shaft 6, the vertical intersection angle θ1 between the flat surface (rear surface 101) of the receiving plate 100 and the rotation shaft 6 can be maintained, thereby making the contact between the opposing surface 71 of the bearing 7 and the rear surface 101 (flat surface) of the receiving plate 100 more stable.

[0066] (2.9) Elastic members The elastic member 300 is located between the positioning member 200 and the cylindrical portion 21, which is part of the pump case 2, in the stretching direction D1. More specifically, the elastic member 300 is located between the bottom 203 of the positioning member 200 and the bottom 211 of the cylindrical portion 21, in the stretching direction D1.

[0067] The elastic member 300 in Embodiment 1 is cylindrical in shape. The elastic member 300 is made of, for example, rubber, and functions as a displacement absorber for at least one of the cylindrical portion 21 of the pump case 2 and the positioning member 200. By including the elastic member 300 in the pump 1, it is possible to suppress the transmission of vibrations generated when the impeller 9 rotates to the cylindrical portion 21 of the pump case 2.

[0068] (2.10) Impeller As shown in Figure 1, the impeller 9 of Embodiment 1 is integrally formed with the rotor 8. The impeller 9 is located in front of the rotor 8. The impeller 9 is located within the first space Sp1 of the pump chamber Sp3.

[0069] The impeller 9 has a front shroud 91 (first shroud) and a rear shroud 92 (second shroud). As shown in Figure 1, the front shroud 91 and the rear shroud 92 are aligned in the extension direction D1. More specifically, the rear surface 910 of the front shroud 91 and the front surface 923 of the rear shroud 92 face each other in the extension direction D1.

[0070] The rear shroud 92 is formed in an annular shape having an inner edge portion 921 and an outer edge portion 922.

[0071] The front shroud 91 is located in front of the rear shroud 92. The front shroud 91 is formed in an annular shape with an inner edge 94 and an outer edge 95.

[0072] As shown in Figure 6, the front shroud 91 has multiple (13 in the example of Figure 6) blade portions 93 facing each other in the direction of rotation (circumferential direction D3). In other words, the impeller 9 has multiple blade portions 93. In the following description, each of the multiple blade portions 93 may be referred to as "blade portion 93".

[0073] The wing portion 93 protrudes rearward from the rear surface 910 of the front shroud 91 along the extension direction D1 (see Figure 1). In other words, the wing portion 93 protrudes toward the front surface 923 of the rear shroud 92 along the extension direction D1. The height H0 of the wing portion 93 along the extension direction D1 in Embodiment 1 is approximately equal to the distance along the extension direction D1 between the rear surface 910 of the front shroud 91 and the front surface 923 of the rear shroud 92.

[0074] In a plan view along the extension direction D1, the blade portion 93 is formed in an arc-shaped plate from the inner edge portion 94 to the outer edge portion 95. The blade portion 93 has a first surface 931 and a second surface 932. The impeller 9 of Embodiment 1 rotates along the circumferential direction D3 of the front shroud 91 in a direction from the second surface 932 toward the first surface 931.

[0075] Multiple flow channels 96 (13 in the example in Figure 6) are formed between the multiple blade sections 93. In other words, the impeller 9 has multiple flow channels 96. In the following description, each of the multiple flow channels 96 may be referred to as "flow channel 96".

[0076] The flow path 96 is formed between two adjacent blade portions 93. More specifically, the flow path 96 is formed between a first surface 931 of one of the two adjacent blade portions 93 and a second surface 932 of the other of the two adjacent blade portions 93. In other words, the flow path 96 is formed between a certain first surface 931 and a certain second surface 932 that is opposite to the first surface 931. The flow path 96 is also formed from the inner edge 94 to the outer edge 95 of the front shroud 91 (impeller 9). When the impeller 9 rotates, liquid flows in the flow path 96 from the inlet 961 located at the inner edge 94 to the outlet 962 located at the outer edge 95.

[0077] Furthermore, the flow path 96 in Embodiment 1 is formed by a plurality of blade portions 93 and a pair of members (a front shroud 91 and a rear shroud 92) that cover both sides of the plurality of blade portions 93, respectively. More specifically, the flow path 96 is formed by being sandwiched between two adjacent blade portions 93 in the circumferential direction D3, and sandwiched between the rear surface 910 of the front shroud 91 and the front surface 923 of the rear shroud 92 in the extension direction D1. The flow path 96 in Embodiment 1 is separated from the pump chamber Sp3 in the extension direction D1 and the circumferential direction D3.

[0078] Figure 9 is a graph showing the relationship between the cross-sectional area of ​​the flow path 96 and the position of the flow path 96 between the inlet 961 and the outlet 962 in Embodiment 1.

[0079] In this disclosure, the "cross-sectional area of ​​the flow path 96" may include the area of ​​the cross-section of the flow path 96 that intersects the flow direction of the flowing liquid when the pump 1 is operating (when the impeller 9 is rotating). In Embodiment 1, as shown in Figure 8, the cross-sectional area of ​​the flow path 96 is the area of ​​a cross-section where the height H0 is the distance along the extension direction D1 from the rear surface 910 of the front shroud 91 to the rear end of the blade portion 93 (height of the blade portion 93), and the width W0 is the length of the perpendicular from the second surface 932 to the first surface 931 opposite the second surface 932. Note that the width W0 may be the length of the perpendicular from the first surface 931 to the second surface 932 opposite the first surface 931. In this disclosure, the cross-sectional area of ​​the flow path 96 is represented with the cross-sectional area of ​​the inlet 961 set to 100%.

[0080] In Figure 6, the cross-sections of the inlet 961, the outlet 962, and the constricted portion 963 are shown in areas marked with dots. In Embodiment 1, the width W1 of the cross-section of the inlet 961 is the length of the perpendicular from the part of the first surface 931 closest to the inner edge 94 to the second surface 932 facing the first surface 931. The height H1 of the cross-section of the inlet 961 is the length along the extension direction D1 of the part of the first surface 931 (wing portion 93) closest to the inner edge 94. In Embodiment 1, the width W2 of the cross-section of the outlet 962 is the length of the perpendicular from the first surface 931 to the part of the second surface 932 facing the first surface 931 closest to the outer edge 95. The height H2 of the cross-section of the outlet 962 is the length along the extension direction D1 of the part of the second surface 932 (wing portion 93) closest to the outer edge 95.

[0081] As shown in Figure 7, in this disclosure, the "position of the flow path 96" is expressed as the ratio of the second distance L2 from the inlet 961 to a certain position to the first distance L1, where the first distance L1 from the inlet 961 to the outlet 962 is set to 100% (second distance L2 / first distance L1 [%]). The first distance L1 is defined, for example, by the length of the first surface 931 or the second surface 932 from the inlet 961 to the outlet 962 in a plan view along the extension direction D1. In Embodiment 1, the first distance L1 is the length of the first surface 931 from the inlet 961 to the outlet 962. The second distance L2 is defined, for example, by the length of the first surface 931 or the second surface 932 from the inlet 961 to the constricted portion 963 in a plan view along the extension direction D1. In Embodiment 1, the second distance L2 is the length of the first surface 931 from the inlet 961 to the constricted portion 963.

[0082] The flow path 96 has a constricted portion 963. In Embodiment 1, the second distance L2 of the constricted portion 963 is assumed to be 19% of the first distance L1. As shown in Figure 9, the cross-sectional area of ​​the constricted portion 963 where the second distance L2 is 19% of the first distance L1 is smaller than the cross-sectional area of ​​the inlet 961 and the cross-sectional area of ​​the outlet 962.

[0083] Since the cross-sectional area of ​​the throttling section 963 is smaller than the cross-sectional area of ​​the inlet 961 and the outlet 962, the throttling section 963 pressurizes the liquid passing through it. Because the throttling section 963 pressurizes the liquid, the pump 1 of Embodiment 1 can suppress the occurrence of cavitation. When cavitation occurs in the flow path, the range in which the liquid flows narrows and the work efficiency of the pump decreases, but the pump 1 of Embodiment 1 suppresses the decrease in work efficiency by suppressing the occurrence of cavitation. In addition, by suppressing the occurrence of cavitation, the pump 1 of Embodiment 1 can suppress the generation of vibration and noise during the operation of the pump 1.

[0084] Furthermore, as shown in Figure 7, the second distance L2 (19%) between the inlet 961 and the diaphragm 963 in Embodiment 1 is shorter than the third distance L3 (81%) between the outlet 962 and the diaphragm 963. The third distance L3 is defined, for example, by the length of the first or second surface 931 from the outlet 962 to the diaphragm 963 in a plan view along the extension direction D1. In Embodiment 1, the third distance L3 is the length of the first surface 931 from the outlet 962 to the diaphragm 963. By making the second distance L2 shorter than the third distance L3, the occurrence of cavitation can be further suppressed. In other words, by having the diaphragm 963 on the inlet 961 side between the inlet 961 and the outlet 962, the occurrence of cavitation can be further suppressed.

[0085] Furthermore, the second distance L2 (19%) between the inlet 961 and the diaphragm 963 in Embodiment 1 is 10% or more of the first distance L1 between the inlet 961 and the outlet 962. By having the second distance L2 be 10% or more of the first distance L1, the occurrence of cavitation can be further suppressed. It is preferable that the second distance L2 between the inlet 961 and the diaphragm 963 is 10% to 30% of the first distance L1. It is even more preferable that the second distance L2 between the inlet 961 and the diaphragm 963 is 15% to 25% of the first distance L1. Furthermore, as in the diaphragm 963 of Embodiment 1, it is even more preferable that the second distance L2 between the inlet 961 and the diaphragm 963 is 18% to 22% of the first distance L1. Furthermore, it is even more preferable that the second distance L2 between the inlet 961 and the diaphragm 963 is 20% of the first distance L1. Furthermore, the throttling portion is not limited to being a throttling portion in one cross-section of the flow path 96, but may be formed to have a predetermined length in the longitudinal direction of the flow path 96.

[0086] Furthermore, as shown in Figure 9, the cross-sectional area of ​​the flow path 96 in Embodiment 1 gradually decreases as it approaches the constricted section 963 from the inlet 961. Because the cross-sectional area of ​​the flow path 96 gradually decreases from the inlet 961 to the constricted section 963, the liquid can flow smoothly through the flow path 96.

[0087] Furthermore, as shown in Figures 6 and 8, the height H0 of the multiple vane portions 93 in Embodiment 1 gradually decreases as it approaches the constriction portion 963 from the inlet 961. By gradually decreasing the height H0 of the multiple vane portions 93 as it approaches the constriction portion 963 from the inlet 961, the cross-sectional area of ​​the flow path 96 can be reduced without narrowing the width W0 of the flow path 96. Alternatively, the cross-sectional area of ​​the flow path 96 can be reduced by changing the thickness of the vane portions 93 to gradually narrow the width W0 of the flow path 96 as it approaches the constriction portion 963 from the inlet 961.

[0088] Furthermore, in the throttling section 963 of Embodiment 1, the height H3 of the throttling section 963 is lower than the height H1 of the inlet 961. By making the height H3 of the throttling section 963 lower than the height H1 of the inlet 961, the cross-sectional area of ​​the flow path 96 can be reduced without narrowing the width W0 (width W3) of the flow path 96.

[0089] As shown in Figure 9, in Embodiment 1, where the second distance L2 is 19% of the first distance L1, the cross-sectional area of ​​the throttling section 963 is 85% or less of the cross-sectional area of ​​the inlet 961 or outlet 962. By setting the cross-sectional area of ​​the throttling section 963 to 85% or less of the cross-sectional area of ​​the inlet 961 or outlet 962, the occurrence of cavitation can be further suppressed. Furthermore, it is preferable that the cross-sectional area of ​​the throttling section 963 be 75% or less of the cross-sectional area of ​​the inlet 961 or outlet 962. By setting the cross-sectional area of ​​the throttling section 963 to 75% or less of the cross-sectional area of ​​the inlet 961 or outlet 962, the occurrence of cavitation can be further suppressed. Moreover, it is more preferable that the cross-sectional area of ​​the throttling section 963 be 70% of the cross-sectional area of ​​the inlet 961 or outlet 962.

[0090] Furthermore, as shown in Figure 9, in Embodiment 1, where the second distance L2 is 19% of the first distance L1, the cross-sectional area of ​​the throttling section 963 is 55% or more of the cross-sectional area of ​​the inlet 961 or outlet 962. By maintaining the amount of liquid flowing through the flow path 96 above a certain level, the work efficiency of the pump 1 can be maintained above a certain level. It is also preferable that the cross-sectional area of ​​the throttling section 963 is 65% or more of the cross-sectional area of ​​the inlet 961 or outlet 962. Moreover, it is even more preferable that the cross-sectional area of ​​the throttling section 963 is 70% of the cross-sectional area of ​​the inlet 961 or outlet 962.

[0091] (3) Pump operation Next, the operation of pump 1 will be explained with reference to Figures 1 and 2.

[0092] First, the control unit 43 of the drive unit 3 controls the energization of the multiple coils 42. Then, the rotor unit 8 rotates due to the interaction between the magnetic field generated by the current flowing through the multiple coils 42 and the magnetic field from the magnets 82, which have multiple magnetic poles, on the rotor unit 8. As the rotor unit 8 rotates, the impeller 9, which is integrally formed with the rotor unit 8, also rotates.

[0093] The rotation of the impeller 9 generates centrifugal force. Due to this centrifugal force, the liquid in the pump chamber Sp3 is discharged from the discharge section 24, and liquid is drawn back into the pump chamber Sp3 through the suction section 22. In other words, the rotation of the impeller 9 causes the pump 1 to draw in and discharge liquid.

[0094] Furthermore, when the impeller 9 rotates, a thrust acts on the impeller 9 in a direction (forward) that moves it towards the intake section 22 along the extension direction D1. Due to this thrust, the impeller 9, rotor section 8, bearing 7, and support plate 100 move forward as a whole. As shown in Figure 2, the front surface 102 of the support plate 100 contacts the rear surface 202 of the positioning member 200, thereby determining the positions of the impeller 9, rotor section 8, bearing 7, and support plate 100 in the extension direction D1. The bearing 7 then rotates with its opposing surface 71 in contact with the rear surface 101 of the support plate 100.

[0095] The control unit 43 of the drive unit 3 controls the supply of power to the multiple coils 42, which stops the rotation of the rotor unit 8 and stops the operation of the pump 1.

[0096] (4) Variations Embodiment 1 is just one of many embodiments of the present disclosure. Embodiment 1 can be modified in various ways depending on the design, etc., as long as it achieves the objectives of the present disclosure.

[0097] The following lists modifications of Embodiment 1. The modifications described below can be applied in appropriate combination with Embodiment 1.

[0098] (4.1) First variation As shown in Figure 10, the pump 1 may be equipped with a positioning member 200a instead of the positioning member 200.

[0099] The positioning member 200a has multiple (two in the example in Figure 10) retaining portions 207.

[0100] Multiple retaining portions 207 protrude from the plane 205 along a direction perpendicular to the extension direction D1. The positioning member 200a having multiple retaining portions 207 can prevent the rotating shaft 6 from coming out of the positioning member 200a.

[0101] (4.2) Second variation Furthermore, as shown in Figure 11, the pump 1 may be equipped with a positioning member 200b instead of the positioning member 200, and an elastic member 300a instead of the elastic member 300.

[0102] As shown in Figure 12, the positioning member 200b has a protrusion 208.

[0103] The protruding portion 208 extends forward from the bottom portion 203 along the extension direction D1 toward the cylindrical portion 21 of the pump case 2. The shape of the protruding portion 208 is cylindrical with a rounded front surface. Furthermore, because the protruding portion 208 is formed on the bottom portion 203, an annular groove is formed between the protruding portion 208 and the edge portion 204.

[0104] As shown in Figure 13, the side circumference 201 of the positioning member 200b is thicker than the side circumference 201 of the positioning member 200 (see Figure 4). Furthermore, the side circumference 201 of the positioning member 200b is cylindrical.

[0105] The positioning member 200b has multiple grooves 209 (two in the example in Figure 13). The multiple grooves 209 are formed on the inner surface of the side circumference 201 along the extension direction D1. More specifically, the multiple grooves 209 are formed at both ends of the plane 205. The positioning member 200b having multiple grooves 209 allows the inner surface of the side circumference 201 to flex elastically when the rotating shaft 6 is inserted, preventing the rotating shaft 6 from coming out.

[0106] As shown in Figure 11, the elastic member 300a has an annular shape. The elastic member 300a is positioned to fit into an annular groove formed between the projection 208 and the edge 204 of the positioning member 200b. Furthermore, when the elastic member 300a is positioned in the annular groove formed between the projection 208 and the edge 204 of the positioning member 200b, it protrudes forward from the projection 208. By including the elastic member 300a in the pump 1, it is possible to suppress the transmission of vibrations generated when the impeller 9 rotates to the cylindrical portion 21 of the pump case 2.

[0107] (4.3) Third Variation Furthermore, as shown in Figure 14, the pump 1 may be equipped with a positioning member 200c instead of a positioning member 200b.

[0108] The positioning member 200c does not have the edge portion 204 that the positioning member 200b according to the second modified example had. Furthermore, the bottom portion 203 of the positioning member 200 is formed to protrude backward as it approaches the outer edge near the outer edge.

[0109] As shown in Figure 15, in the pump 1 according to the third modified example, an elastic member 300a is fitted around the protruding portion 208 of the positioning member 200c. By fitting the elastic member 300a around the protruding portion 208, the elastic member 300a contacts the cylindrical portion 21 of the pump case 2 in the extension direction D1 and the radial direction D2, thereby suppressing the transmission of vibrations generated when the impeller 9 rotates to the cylindrical portion 21 of the pump case 2.

[0110] (4.4) Other variations The multiple blade portions 93 may be formed on the rear shroud 92 instead of the front shroud 91. Alternatively, the multiple blade portions 93 may be formed distributed on both the front shroud 91 and the rear shroud 92.

[0111] The drive unit 3 may have a mechanism that rotates multiple drive magnets around the separation plate 5 along the circumferential direction D3, instead of the molded part 4.

[0112] In Embodiment 1, the case in which the drive unit 3 has a separation plate 5 was illustrated, but the pump case 2 may have the separation plate 5 instead of the drive unit 3. Alternatively, instead of the drive unit 3 having a separation plate 5, at least one of the pump case 2 and the molded part 4 may have a shape that functions as a separation plate 5. For example, the inner circumference of the molded part 4 may be resin-molded to prevent water from entering the inside of the molded part 4 from the pump chamber Sp3.

[0113] (Embodiment 2) As shown in Figure 16, the pump 1 according to Embodiment 2 differs from the pump 1 according to Embodiment 1 in that it is equipped with a positioning member 200d instead of a positioning member 200, and an elastic member 300b instead of an elastic member 300.

[0114] The rotating shaft 6 of Embodiment 2 has a groove 63. The groove 63 is formed along the entire circumference of the first end portion 61 in the circumferential direction.

[0115] The positioning member 200d is located between the receiving plate 100 and the cylindrical portion 21, which is part of the pump case 2, in the extension direction D1. A gap Sp4 is formed between the positioning member 200d and the rear end of the side circumference 212 of the cylindrical portion 21. Due to the presence of the gap Sp4, even if the rotating shaft 6 is assembled at an inclination with respect to the cylindrical portion 21, the positioning member 200d will be inclined with respect to the cylindrical portion 21 in accordance with the inclination angle of the rotating shaft 6.

[0116] The positioning member 200d is a flat plate-shaped member. The positioning member 200d in Embodiment 2 is an annular flat plate having a through hole 210 through which the first end 61 of the rotating shaft 6 passes. The shape of the through hole 210 is semicircular. The through hole 210 is configured so that the positioning member 200d does not rotate relative to the rotating shaft 6 (first end 61) when the first end 61 of the rotating shaft 6 is passed through the through hole 210.

[0117] Furthermore, the through hole 210 in Embodiment 2 is formed to fit into the groove 63 of the rotating shaft 6. That is, the positioning member 200d is formed to fit into the groove 63 of the rotating shaft 6. The positioning member 200d is fixed to the rotating shaft 6 and does not move along the extension direction D1. Therefore, the gap Sp4 between the positioning member 200d and the rear end of the side circumference 212 of the cylindrical portion 21 is maintained.

[0118] The pump 1 of Embodiment 2, by including a flat plate-shaped positioning member 200d, can reduce manufacturing costs compared to, for example, the case where a bottomed cylindrical positioning member 200 is included.

[0119] The elastic member 300b is located between the first end 61 of the rotating shaft 6 and the cylindrical portion 21, which is part of the pump case 2. By including the elastic member 300b in the pump 1, it is possible to suppress the transmission of vibrations generated when the impeller 9 rotates to the cylindrical portion 21, which is part of the pump case 2.

[0120] Embodiment 2 is just one of many embodiments of the present disclosure. Embodiment 2 can be modified in various ways depending on the design, etc., as long as it achieves the objectives of the present disclosure.

[0121] For example, the positioning member 200d may be a member that is fixed to the rotating shaft 6 by an elastic force directed toward the axis Ax1 of the rotating shaft 6 along the radial direction D2 when the rotating shaft 6 is passed through the through hole 210. The positioning member 200d may be a so-called e-ring or the like. That is, the positioning member 200d may be a member with a C-shape in plan view. More specifically, the positioning member 200d may be a flat plate member with a C-shape in plan view. In this disclosure, "C-shape in plan view" may include a shape in which a part of a ring having a through hole (through hole 210) is missing. Furthermore, the through hole 210 (space) through which the rotating shaft 6 passes includes the space that completely surrounds the rotating shaft 6 and the space in which a part of the periphery of the rotating shaft 6 is missing.

[0122] The various configurations (including modified versions) described in Embodiment 2 can be appropriately combined with the various configurations (including modified versions) described in Embodiment 1.

[0123] (summary) As described above, the pump (1) according to the first embodiment comprises an impeller (9) and a drive unit (3). The impeller (9) has a plurality of plate-shaped blades (93) facing each other in the direction of rotation. The drive unit (3) rotates the impeller (9) to cause the liquid to flow. The impeller (9) has a flow path (96). The flow path (96) is formed between the plurality of blades (93). In the flow path (96), the liquid flows from the inlet (961) located on the inner edge (94) of the impeller (9) toward the outlet (962) located on the outer edge (95) of the impeller (9). The flow path (96) has a throttling section (963) between the inlet (961) and the outlet (962) with a cross-sectional area smaller than the cross-sectional area of ​​the inlet (961) and the cross-sectional area of ​​the outlet (962).

[0124] In this embodiment, since the cross-sectional area of ​​the throttling portion (963) is smaller than the cross-sectional area of ​​the inlet (961) and the outlet (962), the throttling portion (963) pressurizes the liquid passing through it. Because the throttling portion (963) pressurizes the liquid, the pump (1) can suppress the generation of cavitation.

[0125] In the pump (1) according to the second embodiment, in the first embodiment, the distance between the inlet (961) and the throttling section (963) (second distance L2) is shorter than the distance between the outlet (962) and the throttling section (963) (third distance L3).

[0126] According to this embodiment, the distance between the inlet (961) and the throttling section (963) (second distance L2) is shorter than the distance between the outlet (962) and the throttling section (963) (third distance L3), thereby further suppressing the occurrence of cavitation.

[0127] In the pump (1) according to the third embodiment, in the second embodiment, the distance between the inlet (961) and the throttling section (963) (second distance L2) is 10% or more of the distance between the inlet (961) and the outlet (962) (first distance L1).

[0128] According to this embodiment, the distance between the inlet (961) and the throttling section (963) (second distance L2) is 10% or more of the distance between the inlet (961) and the outlet (962) (first distance L1), thereby further suppressing the occurrence of cavitation.

[0129] In the pump (1) according to the fourth embodiment, in any of the first to third embodiments, the cross-sectional area of ​​the flow path (96) gradually decreases as it approaches the constriction section (963) from the inlet (961).

[0130] According to this embodiment, the cross-sectional area of ​​the flow path (96) gradually decreases from the inlet (961) to the constricted section (963), so that the liquid can flow smoothly through the flow path (96).

[0131] In the pump (1) according to the fifth embodiment, the height (H0) of the multiple blade sections (93) gradually decreases as it approaches the throttling section (963) from the inlet (961).

[0132] According to this embodiment, by gradually lowering the height (H0) of the multiple vane sections (93) as they approach the constriction section (963) from the inlet (961), the cross-sectional area of ​​the flow path (96) can be reduced without narrowing the width (W0) of the flow path (96).

[0133] In the pump (1) according to the sixth embodiment, in any of the first to fifth embodiments, the cross-sectional area of ​​the throttling portion (963) is 85% or less of the cross-sectional area of ​​the inlet (961) or outlet (962).

[0134] According to this embodiment, the occurrence of cavitation can be further suppressed.

[0135] In the pump (1) according to the seventh embodiment, in any of the first to sixth embodiments, the cross-sectional area of ​​the throttling portion (963) is 55% or more of the cross-sectional area of ​​the inlet (961) or outlet (962).

[0136] According to this embodiment, the amount of liquid flowing through the channel (96) can be kept above a certain level.

[0137] In the pump (1) according to the eighth embodiment, in any of the first to seventh embodiments, the flow path (96) is formed by a plurality of blade portions (93) and a pair of members (front shroud 91, rear shroud 92) that cover both sides of the plurality of blade portions (93).

[0138] According to this embodiment, for example, by forming a flow path (96) surrounded by a plurality of blade portions (93) and a pair of members (front shroud 91, rear shroud 92) that cover both sides of the plurality of blade portions (93), the generation of cavitation can be further suppressed.

[0139] In the pump (1) according to the ninth embodiment, in any of the first to eighth embodiments, the height (H3) of the throttling portion (963) is lower than the height (H1) of the inlet (961).

[0140] According to this embodiment, by making the height (H3) of the throttling portion (963) lower than the height (H1) of the inlet (961), the cross-sectional area of ​​the flow path (96) can be reduced without narrowing the width (W0) of the flow path (96).

[0141] Configurations other than those in the first embodiment are not essential to the pump (1) and can be omitted as appropriate. [Explanation of Symbols]

[0142] 1 pump 3. Drive Unit 9 Impeller 91 Front shroud (a pair of components) 92 Rear shroud (a pair of components) 93. Wing section 94 Inner edge 95 Outer edge 96 Flow channels 961 Inlet 962 Outlet 963 Aperture section H0, H1, H3 Height L1 First distance (distance between the inlet and outlet) L2 Second distance (distance between the inlet and the apex) L3 Third distance (distance between the outlet and the aperture) W0 width

Claims

1. An impeller having multiple plate-shaped blades facing each other in the direction of rotation, A drive unit that rotates the impeller to cause the liquid to flow, Equipped with, The aforementioned impeller is A flow path is formed between the plurality of blade portions, and through which the liquid flows from an inlet located at the inner edge of the impeller to an outlet located at the outer edge of the impeller. The flow path is formed between the inlet and the outlet without narrowing the width of the flow path and has a constricted portion with a cross-sectional area smaller than the cross-sectional area of ​​the inlet and the cross-sectional area of ​​the outlet. The height of the plurality of vanes in the throttling section is lower than the height of the plurality of vanes in the inlet. pump.

2. The distance between the inlet and the constricted portion is shorter than the distance between the outlet and the constricted portion. The pump according to claim 1.

3. The distance between the inlet and the constricted portion is 10% or more of the distance between the inlet and the outlet. The pump according to claim 2.

4. The cross-sectional area of ​​the flow path gradually decreases as it approaches the constricted portion from the inlet. The pump according to any one of claims 1 to 3.

5. The height of the plurality of vane sections gradually decreases as they approach the constricted section from the inlet. The pump according to claim 4.

6. The cross-sectional area of ​​the constricted portion is 85% or less of the cross-sectional area of ​​the inlet or outlet. The pump according to any one of claims 1 to 5.

7. The cross-sectional area of ​​the constricted portion is 55% or more of the cross-sectional area of ​​the inlet or outlet. The pump according to any one of claims 1 to 6.

8. The flow path is formed by the plurality of vane portions and a pair of members that cover both sides of the plurality of vane portions, The pump according to any one of claims 1 to 7.

9. In the aforementioned throttling section, the height of the throttling section is lower than the height of the inlet. The pump according to any one of claims 1 to 8.

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