Pumping device
By introducing fluid control shapes like ribs at the connection point between the opposing wall and suction pipe, the pump device enhances fluid flow into the impeller, addressing inefficiencies and improving efficiency by generating turbulence and reducing backflow.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- NIDEC INSTR CORP
- Filing Date
- 2024-12-27
- Publication Date
- 2026-07-09
AI Technical Summary
Existing pump devices suffer from inefficiencies due to fluid flowing into the gap between the pump cover and impeller instead of entering the impeller, which reduces the flow rate and overall pump efficiency.
The pump device incorporates a fluid control shape, such as ribs or protrusions, at the connection point between the opposing wall and suction pipe to generate turbulence and direct fluid into the impeller, enhancing the flow rate and preventing backflow.
The implementation of fluid control shapes increases the flow rate into the impeller, improving pump efficiency by generating turbulence and reducing backflow, as demonstrated by a 25.02 N thrust force compared to 10.88 N without the ribs.
Smart Images
Figure 2026115293000001_ABST
Abstract
Description
Technical Field
[0006] , , , ,
[0001] The present invention relates to a pump device.
Background Art
[0002] Patent Document 1 describes a pump device that rotates an impeller disposed in a pump chamber by a motor. The pump device of Patent Document 1 includes a pump main body in which a stator is molded inside a housing, and a pump cover that forms a pump chamber between the housing and the pump cover. A rotor that rotates integrally with the impeller is disposed at the center of the stator in the radial direction.
[0003] The pump cover is provided with a fluid discharge pipe and a suction pipe. The pump cover has a suction pipe provided at the center in the radial direction of a wall portion that faces the impeller from the side opposite to the housing, and a discharge pipe provided on a side wall portion that surrounds the outer peripheral side of the impeller.
[0004] The impeller is provided with blade portions that curve in the circumferential direction and extend radially outward, and includes a frustum-shaped cover body that covers the blade portions from the side opposite to the housing. The fluid flows into the impeller through a hole provided at the center in the radial direction of the cover body. Due to the rotation of the impeller, the fluid is sent out to the outer peripheral side and discharged from the discharge pipe.
[0005] The cover body of the impeller faces the pump cover with a predetermined gap (clearance). In Patent Document 1, a convex portion that protrudes toward the pump cover side is provided on the outer peripheral edge of the cover body. At the location where the convex portion is provided, the clearance between the pump cover and the impeller becomes small. Therefore, it is suppressed that a return flow occurs in which the fluid discharged from the outer periphery of the impeller returns to the suction pipe side through the gap with the pump cover, and the pump efficiency is improved.
Prior Art Documents
Patent Documents
[0006]
Patent Document 1
[0007] Some of the fluid flowing into the pump chamber from the suction pipe of the pump cover does not flow into the impeller but instead flows into the gap between the pump cover and the impeller. Pump efficiency can be improved by increasing the flow rate of the fluid that flows into the impeller from the fluid flowing into the pump chamber. However, while Patent Document 1 proposes providing a shape on the outer circumference of the impeller to suppress backflow, it does not propose controlling the water flow around the suction pipe to increase the amount of fluid flowing into the impeller.
[0008] In view of the above problems, the object of the present invention is to improve pump efficiency by increasing the flow rate of fluid flowing into the impeller in a pump device that rotates the impeller inside the pump chamber. [Means for solving the problem]
[0009] To solve the above problems, one embodiment of the pump device according to the present invention comprises a rotor and a stator surrounding the outer circumference of the rotor, an impeller positioned opposite the stator on one side in the axial direction along the rotation axis of the rotor and rotating integrally with the rotor, and a casing forming a pump chamber in which the impeller is arranged, wherein the casing is provided with a cover that covers the impeller from one side in the axial direction, and the cover is positioned on the impeller. The cover comprises an opposing wall portion facing each other from one side in the linear direction, a side wall portion surrounding the outer circumference of the impeller and connected to the outer end of the opposing wall portion, an intake pipe extending from the radial center of the opposing wall portion with respect to the axis of rotation to one side in the axial direction, and a discharge pipe connected to the side wall portion, wherein the impeller comprises a first end plate portion facing the opposing wall portion, a second end plate portion facing the first end plate portion from the other side in the axial direction and connected to the rotor, and a blade portion disposed between the first end plate portion and the second end plate portion, the first end plate portion being provided with a fluid intake hole facing the intake pipe, and a fluid control shape protruding from the intake pipe or the opposing wall portion is provided at the connection point where the opposing wall portion and the intake pipe are connected inside the cover. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a cross-sectional view of a pump device according to an embodiment of the present invention. [Figure 2] Figure 2 is a partially enlarged cross-sectional view of the impeller and cover. [Figure 3] Figure 3 is a partially enlarged cross-sectional perspective view showing the radially central portion of the impeller and cover. [Figure 4] Figure 4 is a plan view of the fluid control geometry as seen from the other side in the axial direction. [Modes for carrying out the invention]
[0011] An embodiment of the pump device 1 will be described below with reference to the drawings.
[0012] (Overall structure) Figure 1 is a cross-sectional view of a pump device 1 according to an embodiment of the present invention. As shown in Figure 1, the pump device 1 comprises a motor 2, an impeller 3 rotated by the motor 2, and a casing 4 housing the motor 2 and the impeller 3. The motor 2 comprises a rotor 5 and a stator 6 surrounding the outer circumference of the rotor 5. The impeller 3 rotates integrally with the rotor 5.
[0013] In the following explanation, the direction along the rotation axis L of the rotor 5 is referred to as the axial direction, with one side of the axial direction designated as L1 and the other side as L2. The radial direction refers to the radial direction centered on the rotation axis L. The circumferential direction also refers to the circumferential direction centered on the rotation axis L.
[0014] The impeller 3 is positioned at one end L1 in the axial direction of the rotor 5. The rotor 5 comprises a rotor member 7 extending in the axial direction, a magnet 8 positioned on the outer circumferential surface of the rotor member 7, and a radial bearing 9 fixed to the radial center of the rotor member 7 by insert molding. The pump device 1 comprises a support shaft 10 fixed to the casing 4. The rotor 5 is rotatably supported on the support shaft 10 via the radial bearing 9.
[0015] The rotor member 7 comprises a cylindrical portion 71 extending in the axial direction and a seat portion 72 that protrudes radially outward from the middle of the cylindrical portion 71 in the axial direction. A magnet 8 is fixed to the portion L2 of the cylindrical portion 71 on the other side in the axial direction from the seat portion 72. The seat portion 72 contacts the magnet 8 from one side L1 in the axial direction and supports the magnet 8.
[0016] A disc-shaped second end plate portion 32, which constitutes the impeller 3, is connected to one end L1 in the axial direction of the cylindrical portion 71. An impeller member 30 is fixed to the second end plate portion 32 from one side L1 in the axial direction. The impeller member 30 has a first end plate portion 31 that faces the second end plate portion 32 from one side L1 in the axial direction, and a blade portion 33 that protrudes from the first end plate portion 31 to the other side L2 in the axial direction. The impeller member 30 is fixed to the second end plate portion 32 via the blade portion 33.
[0017] The first end plate portion 31 is a frustoconical shape that slopes toward one side L1 in the axial direction as it approaches the radial center. At the radial center of the first end plate portion 31 is a fluid intake hole 34 that penetrates the first end plate portion 31, and a cylindrical portion 3 that protrudes from the edge of the fluid intake hole 34 toward one side L1 in the axial direction. 5 is provided. The blade portions 33 are arranged at equal angular intervals around the fluid suction holes 34 between the first end plate portion 31 and the second end plate portion 32. Each of the plurality of blade portions 33 extends radially outward while curving in the circumferential direction.
[0018] The stator 6 includes an annular stator core 61 surrounding the outer peripheries of the rotor member 7 and the magnet 8, and a coil 63 wound around the salient poles of the stator core 61 via an insulator 62. On the other side L2 in the axial direction of the stator 6, a circuit board (not shown) for supplying a driving current to the coil 63 is arranged.
[0019] The casing 4 includes a housing 41 covering the stator 6, and a cover 42 covered on the housing 41 from one side L1 in the axial direction. The housing 41 is a resin sealing member in which the stator 6 is inserted. The housing 41 includes a first partition portion 43 covering one side L1 in the axial direction of the stator 6, a second partition portion 44 connected to the inner peripheral edge of the first partition portion 43 and covering the stator 6 from the inside in the radial direction, a bottom portion 45 closing the end on the other side L2 in the axial direction of the second partition portion 44 and covering the other side L2 in the axial direction of the stator 6, and a body portion 46 connected to the outer peripheral edge of the first partition portion 43 and covering the stator 6 from the outside in the radial direction.
[0020] The pump chamber 40 in which the impeller 3 is arranged is defined by the housing 41 and the cover 42. At the center in the radial direction of the cover 42, a suction pipe 47 extending to one side L1 in the axial direction is provided. Also, the cover 42 is provided with a discharge pipe (not shown) extending in the tangential direction of the outer peripheral surface of the pump chamber 40. The cover 42 is fixed to the housing 41 by welding. At the end on the other side L2 in the axial direction of the cover 42, a flange portion 48 protruding radially outward is provided. A welding groove in which welding ribs provided on the flange portion 48 of the cover 42 are welded is formed in a flange portion 49 protruding radially outward from the body portion 46 of the housing 41.
[0021] The cover 42 is placed on the impeller 3 from one axial side L1. The cover 42 includes an opposing wall portion 50 that faces the impeller 3 from one axial side L1, and a side wall portion 51 that surrounds the outer periphery of the impeller 3 and is connected to the outer peripheral edge of the opposing wall portion 50. The opposing wall portion 50, the side wall portion 51, and the first partition portion 43 of the housing 41 partition the pump chamber 40. The suction pipe 47 extends from the radial center of the opposing wall portion 50 to one axial side L1, and a discharge pipe (not shown) is connected to the side wall portion 51.
[0022] The cover 42 is provided with three support portions 11 that extend from the inner peripheral surface of the suction pipe 47 to the other axial side L2. At the tip of the support portion 11, a cylindrical portion 12 into which the end of the support shaft 10 on one axial side L1 is inserted is provided. The end of the support shaft 10 on the other axial side L2 fits into a shaft hole 13 provided in the bottom portion 45 of the housing 41. A thrust bearing 14 attached to the end of the support shaft 10 on one axial side L1 is disposed between the end of the radial bearing 9 on one axial side L1 and the tip of the cylindrical portion 12. When the rotor 5 and the impeller 3 rotate, the impeller 3 is biased toward one axial side L1, and the radial bearing 9 is in sliding contact with the thrust bearing 14.
[0023] (Fluid control shape) FIG. 2 is a partially enlarged cross-sectional view of the impeller 3 and the cover 42. FIG. 3 is a partially enlarged cross-sectional perspective view of the radially central portion of the impeller 3 and the cover 42. FIG. 4 is a plan view of the fluid control shape C as viewed from the other axial side L2. As shown in FIGS. 2 and 3, the suction pipe 47 includes a first cylindrical portion 52 connected to the inner peripheral edge of the opposing wall portion 50, and a second cylindrical portion 53 connected to the first cylindrical portion 52 and extending from the first cylindrical portion 52 to one axial side L1. The first cylindrical portion 52 has a greater wall thickness than the second cylindrical portion 53 and protrudes radially outward from the outer peripheral surface of the second cylindrical portion 53. When connecting the suction pipe 47 to a fluid supply pipe (not shown), the first cylindrical portion 52 functions as a pedestal portion that supports a sealing material (not shown) mounted on the outer periphery of the second cylindrical portion 53 from the other axial side L2. It functions as a pedestal portion that supports a sealing material (not shown) mounted on the outer periphery of the second cylindrical portion 53 from the other axial side L2.
[0024] As shown in Figures 2 and 3, the inner circumferential surface of the first cylindrical portion 52 is provided with a recess 54 that is recessed radially outward. The recess 54 is a weight-reducing portion that prevents the wall thickness of the first cylindrical portion 52 from increasing, and is provided around the entire circumference of the inner circumferential surface of the first cylindrical portion 52. The recess 54 extends axially to the corner where the first cylindrical portion 52 and the opposing wall portion 50 connect, and opens into the inner surface of the pump chamber 40 formed by the opposing wall portion 50. As described above, a cylindrical portion 35 surrounding the fluid intake hole 34 is provided in the radial center of the impeller 3, and the tip of the cylindrical portion 35 extends inward into the first cylindrical portion 52 and is positioned within the recess 54.
[0025] As shown in Figure 3, if the region L2 on the other side of the recess 54 in the axial direction is designated as the first region 55, and the region L1 on the other side of the axial direction relative to the first region 55 is designated as the second region 56, then the second region 56 is provided with ribs 57 extending radially inward from the radially outer inner circumferential surface 54a of the recess 54. The ribs 57 are arranged circumferentially at equal angular intervals around the entire circumference inside the recess 54. The ribs 57 do not extend to the opposing wall portion 50 and are not located in the first region 55. The tip of the cylindrical portion 35 of the impeller 3 is located in the first region 55, and the ribs 57 are located on one side L1 in the axial direction of the cylindrical portion 35. Therefore, the cylindrical portion 35 and the ribs 57 do not interfere with each other.
[0026] As shown in Figure 3, the radially inner tip surface of the rib 57 lies on the same plane as the inner circumferential surface of the suction pipe 47. The inner diameter of the fluid intake hole 34, which opens on the other axial side L2 of the rib 57, is smaller than the inner diameter of the suction pipe 47. Therefore, the rib 57 is located radially outward from the inner circumferential surface of the fluid intake hole 34.
[0027] The rib 57 is positioned at the connection point where the inner surface of the opposing wall 50 and the inner circumferential surface of the suction pipe 47 are connected. This is the point where the suction pipe 47 and the pump chamber 40 are connected, and the rib 57 provided at this point functions as a fluid control shape C that controls the inflow of fluid into the pump chamber 40 and the impeller 3. By providing the rib 57 at this point, turbulence is generated as the impeller 3 rotates. This obstructs the flow of fluid toward the gap S between the opposing wall 50 and the first end plate 31 of the impeller 3, increasing the flow rate into the impeller 3. Therefore, pump efficiency is improved.
[0028] As shown in Figures 2 and 3, the ribs 57 are inclined in a direction toward one side in the circumferential direction as they move radially inward. As shown in Figure 3, in this embodiment, the ribs 57 are inclined toward the front side R1 in the rotational direction of the impeller 3 as they move radially inward. Providing ribs 57 with such an inclined direction makes it easier for turbulence to be generated by the fluid colliding with the ribs 57 as the impeller 3 rotates. Therefore, pump efficiency is improved.
[0029] In this embodiment, in order to avoid an increase in wall thickness at the point where the first cylindrical portion 52 of the suction pipe 47 protrudes radially outward, a recess 54 is provided on the inner circumferential surface of the first cylindrical portion 52. At the point where the recess 54 is provided, the clearance between the cover 42 and the impeller 3 increases, making it easier for fluid to flow into the gap S between the opposing wall portion 50 and the impeller 3, raising concerns about a decrease in pump efficiency. Therefore, a structure is adopted in which a rib 57 that functions as a fluid control shape C is arranged using the recess 54 to generate turbulence and improve pump efficiency.
[0030] The inventors performed fluid analysis using a three-dimensional model of the pump device 1 of this embodiment and a three-dimensional model of a pump device without the ribs 57, and determined the pressure distribution in the pump chamber 40 and the thrust force that biases the impeller 3 to one side L1 in the axial direction when the impeller 3 rotates. An increase in thrust force means an improvement in pump efficiency. The thrust force with the ribs 57 was 25.02 N, while the thrust force without the ribs 57 was: The value was 10.88N. Therefore, it was confirmed that the thrust force increases and pump efficiency improves when rib 57 is provided.
[0031] (Effects and Benefits) As described above, the pump device 1 of this embodiment includes a rotor 5 and a stator 6 surrounding the outer circumference of the rotor 5, an impeller 3 positioned opposite the stator 6 on one side L1 in the axial direction along the rotation axis L of the rotor 5 and rotating integrally with the rotor 5, and a casing 4 forming a pump chamber 40 in which the impeller 3 is arranged. The casing 4 includes a cover 42 that covers the impeller 3 from one side L1 in the axial direction. The cover 42 includes an opposing wall portion 50 that faces the impeller 3 from one side L1 in the axial direction, a side wall portion 51 that surrounds the outer circumference of the impeller 3 and is connected to the outer peripheral end of the opposing wall portion 50, a suction pipe 47 extending from the radial center of the opposing wall portion 50 with respect to the rotation axis L to one side L1 in the axial direction, and a discharge pipe (not shown) connected to the side wall portion 51. The impeller 3 comprises a first end plate portion 31 facing the opposing wall portion 50, a second end plate portion 32 facing the first end plate portion 31 from the other axial side L2 and connected to the rotor 5, and a blade portion 33 positioned between the first end plate portion 31 and the second end plate portion 32. A fluid intake hole 34 facing the intake pipe 47 is provided in the first end plate portion 31. Inside the cover 42, a rib 57 as a fluid control shape C is provided at the connection point where the opposing wall portion 50 and the intake pipe 47 are connected, protruding from the intake pipe 47.
[0032] In this embodiment, the provision of ribs 57 in the above-mentioned area generates turbulence as the impeller 3 rotates. This obstructs the fluid flow from the suction pipe 47 to the gap S between the opposing wall portion 50 and the first end plate portion 31, and increases the flow rate into the impeller 3 from the fluid suction hole 34. Therefore, pump efficiency can be improved.
[0033] Furthermore, when a fluid control shape C is provided at the connection point where the opposing wall portion 50 and the suction pipe 47 are connected, the shape is not limited to a shape that protrudes from the suction pipe 47. For example, at the connection point where the opposing wall portion 50 and the suction pipe 47 are connected, a shape may be provided that protrudes from the inner surface 50a of the opposing wall portion 50 toward the first end plate portion 31. In other words, it is sufficient that a fluid control shape C protruding from either the opposing wall portion 50 or the suction pipe 47 is provided at the connection point where the opposing wall portion 50 and the suction pipe 47 are connected. The fluid control shape C is not limited to a rib.
[0034] In this embodiment, the rib 57, which is the fluid control shape C, is located radially outward from the inner circumferential surface of the fluid intake hole 34. This prevents the inflow of fluid into the impeller 3 from being obstructed by the rib 57.
[0035] In this embodiment, multiple ribs 57 extending radially inward are arranged circumferentially at the connection point where the opposing wall portion 50 and the suction pipe 47 are connected in the cover 42. By providing radially extending ribs 57, turbulence is generated around the ribs 57 as the impeller 3 rotates. Therefore, pump efficiency can be improved.
[0036] In this embodiment, the fluid control shape C is placed in a recess 54 provided on the inner circumferential surface of the suction pipe 47. However, the recess 54 may be omitted, and the fluid control shape C may be provided projecting radially inward from the inner circumferential surface of the suction pipe 47. Furthermore, if the fluid control shape C is provided on the opposing wall portion 50, ribs projecting axially from the opposing wall portion 50 to the other side L2 may be provided radially around the suction pipe 47.
[0037] In this configuration, the ribs 57 are inclined radially outward, towards the front side R1 in the direction of rotation of the impeller 3. With this shape, turbulence is easily generated around the ribs 57 as the impeller 3 rotates. Therefore, pump efficiency can be further improved.
[0038] In this embodiment, a recess 54 is provided at the connection point where the opposing wall portion 50 and the suction pipe 47 are connected in the cover 42, recessing radially outward from the inner circumferential surface of the suction pipe 47, and a rib 57 is arranged within the recess 54. This allows the rib 57 to be positioned on the outer circumference side of the inner diameter of the suction pipe 47, making it easier to position the rib 57 radially outward from the fluid intake hole 34.
[0039] In this embodiment, the impeller 3 includes a cylindrical portion 35 that protrudes from the edge of the fluid intake hole 34 on one side L1 in the axial direction. The tip of the cylindrical portion 35 is inserted into a recess 54, and a rib 57 is positioned on one side L1 in the axial direction relative to the cylindrical portion 35. This structure allows the fluid intake hole 34 to open inside the suction pipe 47, making it easier for fluid to flow into the impeller 3.
[0040] In this embodiment, the suction pipe 47 comprises a first cylindrical portion 52 connected to the inner periphery of the opposing wall portion 50, and a second cylindrical portion 53 extending from the first cylindrical portion 52 to one side L1 in the axial direction. The first cylindrical portion 52 protrudes radially outward from the second cylindrical portion 53, and the recess 54 is provided inside the first cylindrical portion 52. The first cylindrical portion 52 functions as a base portion that supports the sealing material fitted to the outer circumference of the second cylindrical portion 53 from the other side L2 in the axial direction. This prevents the area on the outer circumference of the suction pipe 47 where the base portion protruding radially outward is provided from becoming thicker, thereby suppressing molding defects when manufacturing the cover 42 and improving dimensional stability. In addition, the recess 54 provided as a weight-reducing portion can be used to provide a fluid control shape C.
[0041] In this embodiment, the ribs 57 are arranged at equal angular intervals around the entire inner surface of the intake pipe 47. This allows turbulence to be generated around the entire circumference.
[0042] (summary) The present invention can take the following forms.
[0043] (1) A rotor and a stator surrounding the outer circumference of the rotor, An impeller is positioned opposite the stator on one side in the axial direction along the rotation axis of the rotor and rotates integrally with the rotor, The casing comprises a pump chamber in which the impeller is arranged, The casing comprises a cover that covers the impeller from one side in the axial direction, The cover comprises an opposing wall portion facing the impeller from one side in the axial direction, a side wall portion surrounding the outer circumference of the impeller and connected to the outer peripheral end of the opposing wall portion, an intake pipe extending from the radial center of the opposing wall portion with respect to the axis of rotation to one side in the axial direction, and a discharge pipe connected to the side wall portion. The impeller comprises a first end plate portion facing the opposing wall portion, a second end plate portion facing the first end plate portion from the other side in the axial direction and connected to the rotor, and a blade portion disposed between the first end plate portion and the second end plate portion, the first end plate portion being provided with a fluid intake hole facing the intake pipe, A pump device characterized in that a fluid control shape protruding from the suction pipe or the opposing wall is provided at the connection point where the opposing wall and the suction pipe are connected inside the cover.
[0044] (2) The pump device according to (1) above, characterized in that the fluid control shape is located radially outward from the inner circumferential surface of the fluid intake hole.
[0045] (3) In the aforementioned cover, at the connection point where the opposing wall portion and the suction pipe are connected, Multiple ribs extending radially inward are arranged in a line in the circumferential direction. The pump device according to (1) above, characterized in that the fluid control shape is the rib.
[0046] (4) The pump device according to (3) above, characterized in that the ribs are inclined toward the front side in the rotational direction of the impeller as they extend outward in the radial direction.
[0047] (5) In the cover, at the connection point where the opposing wall portion and the suction pipe are connected, A recess is provided in the inner circumferential surface of the suction pipe that is recessed radially outward. The pump device according to (3) above, characterized in that the ribs are arranged in the recess.
[0048] (6) The impeller includes a cylindrical portion that protrudes from the edge of the fluid intake hole to one side in the axial direction, and the tip of the cylindrical portion is positioned in the recess. The pump device according to (5) above, characterized in that the rib is arranged on one side in the axial direction with respect to the cylindrical portion.
[0049] (7) The suction pipe comprises a first cylindrical portion connected to the inner peripheral edge of the opposing wall portion, and a second cylindrical portion extending from the first cylindrical portion to one side in the axial direction. The first cylindrical portion protrudes radially outward from the second cylindrical portion, and the recess is provided on the inside of the first cylindrical portion. The pump device according to (5) above, characterized in that the first cylindrical portion functions as a base portion that supports a sealing material fitted to the outer circumference of the second cylindrical portion from the other side in the axial direction.
[0050] (8) The pump device according to any one of (1) to (7) above, characterized in that the ribs are arranged at equal angular intervals around the entire circumference of the suction pipe. [Explanation of Symbols]
[0051] 1...Pump device, 2...Motor, 3...Impeller, 4...Casing, 5...Rotor, 6...Stator, 7...Rotor component, 8...Magnet, 9...Radial bearing, 10...Support shaft, 11...Support part, 12...Cylinder part, 13...Shaft hole, 14...Thrust bearing, 30...Impeller component, 31...First end plate part, 32...Second end plate part, 33...Blade part, 34...Fluid intake hole, 35...Cylinder part, 40...Pump chamber, 41...Housing, 42...Cover, 43...First bulkhead part, 44...Second bulkhead part, 45...Bottom part, 4 6...Body, 47...Intake pipe, 48...Flange section, 49...Flange section, 50...Opposite wall section, 50a...Inner surface, 51...Side wall section, 52...First cylindrical section, 53...Second cylindrical section, 54...Recess, 54a...Inner circumferential surface, 55...First region, 56...Second region, 57...Rib, 61...Stator core, 62...Insulator, 63...Coil, 71...Cylindrical section, 72...Seat section, C...Fluid control shape, L...Rotation axis, L1...One side in the axial direction, L2...Other side in the axial direction, R1...Front side in the rotation direction, S...Gap
Claims
1. A rotor and a stator surrounding the outer circumference of the rotor, An impeller is positioned opposite the stator on one side in the axial direction along the rotation axis of the rotor and rotates integrally with the rotor, The casing comprises a pump chamber in which the impeller is arranged, The casing comprises a cover that covers the impeller from one side in the axial direction, The cover comprises an opposing wall portion facing the impeller from one side in the axial direction, a side wall portion surrounding the outer circumference of the impeller and connected to the outer peripheral end of the opposing wall portion, an intake pipe extending from the radial center of the opposing wall portion with respect to the axis of rotation to one side in the axial direction, and a discharge pipe connected to the side wall portion. The impeller comprises a first end plate portion facing the opposing wall portion, a second end plate portion facing the first end plate portion from the other side in the axial direction and connected to the rotor, and a blade portion disposed between the first end plate portion and the second end plate portion, the first end plate portion being provided with a fluid intake hole facing the intake pipe, A pump device characterized in that a fluid control shape protruding from the suction pipe or the opposing wall is provided at the connection point where the opposing wall and the suction pipe are connected inside the cover.
2. The pump device according to claim 1, characterized in that the fluid control shape is located radially outward from the inner circumferential surface of the fluid intake hole.
3. In the cover, at the connection point where the opposing wall portion and the suction pipe are connected, Multiple ribs extending radially inward are arranged in a line in the circumferential direction. The pump device according to claim 1, characterized in that the fluid control shape is the rib.
4. The pump device according to claim 3, characterized in that the ribs are inclined toward the front side in the rotational direction of the impeller as they extend outward in the radial direction.
5. In the cover, at the connection point where the opposing wall portion and the suction pipe are connected, A recess is provided in the inner circumferential surface of the suction pipe that is recessed radially outward. The pump device according to claim 3, characterized in that the rib is arranged in the recess.
6. The impeller includes a cylindrical portion that protrudes from the edge of the fluid intake hole to one side in the axial direction, and the tip of the cylindrical portion is positioned in the recess. The pump device according to claim 5, characterized in that the rib is arranged on one side in the axial direction with respect to the cylindrical portion.
7. The suction pipe comprises a first cylindrical portion connected to the inner peripheral edge of the opposing wall portion, and a second cylindrical portion extending from the first cylindrical portion to one side in the axial direction. The first cylindrical portion protrudes radially outward from the second cylindrical portion, and the recess is provided on the inside of the first cylindrical portion. The pump device according to claim 5, characterized in that the first cylindrical portion functions as a base portion that supports a sealing material fitted to the outer circumference of the second cylindrical portion from the other side in the axial direction.
8. The pump device according to claim 3, characterized in that the ribs are arranged at equal angular intervals around the entire circumference of the suction pipe.