Pump equipment

Abstract

A pump device capable of generating a smooth flow of fluid toward an impeller. [Solution] The pump device 1 comprises a shaft 22, an impeller 31 supported on the shaft 22, a fluid inlet 14, a fluid outlet 15, a cover 20 covering the end of the shaft 22, and a plurality of stator vanes 21 connecting the inlet 14 and the cover 20.

Description

[Technical Field]

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

[0002] For example, Patent Document 1 discloses an electric pump for circulating cooling water in an engine or the like. In this electric pump, cooling water is pumped from an inlet pipe through an outlet pipe by the rotation of an impeller. A covering portion that supports the upper end of a shaft that rotatably supports the impeller is attached to the inner surface of the inlet pipe by three support ribs. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6686664 Summary of the Invention [Problem to be solved by the invention]

[0004] The support rib is formed in a flat plate shape along an imaginary plane including the axis of the shaft. That is, the support rib is formed linearly along the axis of the shaft. As a result, the cooling water flowing in from the inlet pipe collides linearly with the covering and the axial center of the impeller, and the covering hinders the smooth flow of the cooling water. This reduces the efficiency of the electric pump.

[0005] The present invention has been made in view of the above-mentioned problems, and one of its objects is to provide a pump device that can generate a smooth flow of fluid toward an impeller. [Means for solving the problem]

[0006] A pump device according to one aspect of the present invention comprises a shaft, an impeller fixed to the shaft, an inlet for a fluid, an outlet for the fluid, a cover covering the end of the shaft, and a plurality of stator vanes connecting the inlet and the cover. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view showing a schematic structure of a pump device 1 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 4] FIG. 3 is a partially enlarged cross-sectional view of a part of FIG. 2. [Figure 5] FIG. 5 is a partially enlarged cross-sectional view taken along line 5-5 in FIG. 2. [Figure 6] FIG. 2 is a perspective view schematically illustrating the structure of a cover 20 and a stator blade 21 according to a specific example. [Figure 7] FIG. 7 is a perspective cross-sectional view taken along line 7-7 in FIG. 2. [Figure 8] FIG. 8 is a partially enlarged cross-sectional view taken along line 8-8 in FIG. 2. [Figure 9] FIG. 10 is a plan view schematically showing the structure of a stator blade 21 according to another specific example. [Figure 10] FIG. 10 is a plan view schematically showing the structure of a stator blade 21 according to another specific example. [Figure 11] 10 is a graph showing the efficiency of the pump device calculated by fluid analysis. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing the structure of a pump device 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1. The pump device 1 is, for example, a water pump. A water pump is a centrifugal pump for transferring (pressurizing) a fluid, i.e., cooling water. The pump device 1 is attached, for example, to an engine room or motor room of a vehicle. The pump device 1 is used to cool a driving source, such as a vehicle engine or motor, by transferring cooling water to the driving source.

[0009] In the pump device 1, the direction along the axis x is defined as the axial direction. In this axial direction, one side is defined as the upper side, and the other side is defined as the lower side. The upper side and the lower side do not necessarily coincide with the upper side and the lower side in the direction of gravity. Furthermore, the direction perpendicular to the axis x is defined as the radial direction. In the radial direction, the direction approaching the axis x is defined as the inner circumferential side, and the direction away from the axis x is defined as the outer circumferential side. Furthermore, a circumferential direction is defined around the axis x. The clockwise and counterclockwise directions in the circumferential direction are defined as the directions when viewed from above in the axial direction.

[0010] 1 and 2, the pump device 1 in this example includes a casing 10, which is a tube formed in a cylindrical shape with an axis x as a central axis. The casing 10 includes a lower casing 11 disposed on the bottom and an upper casing 12 attached to the lower casing 11 from above. The lower casing 11 and the upper casing 12 are formed by, for example, injection molding from a resin material. The lower casing 11 and the upper casing 12 define an internal space S of the casing 10.

[0011] The upper casing 12 has a main body 13 and an inlet section 14 and an outlet section 15 formed integrally with the main body 13. The main body 13 is formed, for example, in a cylindrical shape centered on the axis x. The main body 13 has an upper portion 13a having a small diameter (hereinafter referred to as the "small diameter portion") and a lower portion 13b having a large diameter (hereinafter referred to as the "large diameter portion"). Both the small diameter portion 13a and the large diameter portion 13b are formed in a cylindrical shape. In the radial direction, the diameter of the small diameter portion 13a is smaller than the diameter of the large diameter portion 13b.

[0012] The inlet portion 14 protrudes upward from the upper surface of the small diameter portion 13a of the main body portion 13 along the axis x. The inlet portion 14 is formed, for example, in a cylindrical shape centered on the axis x. The inlet portion 14 allows the fluid to flow into the internal space S of the casing 10. The outlet portion 15 protrudes outward from the small diameter portion 13a of the main body portion 13 along a tangent to an imaginary circle centered on the axis x. The outlet portion 15 is formed, for example, in a cylindrical shape centered on the tangent. The outlet portion 15 allows the fluid to flow out of the internal space S of the casing 10.

[0013] As shown in FIG. 2, the lower casing 11 has a bottom wall 16, an inner wall 17, a top wall 18, and an outer wall 19. The bottom wall 16 is formed, for example, in the shape of a flat disk perpendicular to the axis x. The inner wall 17 extends upward from the outer peripheral edge of the bottom wall 16. The inner wall 17 is formed in a cylindrical shape centered on the axis x. The top wall 18 extends outer peripherally from the upper edge of the inner wall 17. The top wall 18 is formed in an annular shape centered on the axis x. The outer wall 19 extends downward from the outer peripheral edge of the top wall 18. The outer wall 19 is formed in a cylindrical shape centered on the axis x. In this example, the main body 13 of the upper casing 12 covers the outer peripheral surface of the outer wall 19.

[0014] The internal space S of the casing 10 has a first space S1 defined within the small diameter portion 13a of the upper casing 12 and a second space S2 defined within the inner wall 17 of the lower casing 11. In this example, the first space S1 and the second space S2 are both roughly cylindrical spaces centered on the axis x. The first space S1 and the second space S2 are in communication with each other. In the radial direction, the diameter of the first space S1 is larger than the diameter of the second space S2. Meanwhile, in the axial direction, the height of the first space S1 is smaller than the height of the second space S2.

[0015] This internal space S is sealed by the lower casing 11 and the upper casing 12. The fluid flows from the inlet 14 through the internal space S of the casing 10 and out through the outlet 15. This fluid is a liquid such as a coolant. The liquid includes, for example, water. This water may also include other liquids. The other liquids may include, for example, antifreeze such as propylene glycol or ethylene glycol, rust inhibitors, etc.

[0016] The upper casing 12 has a cover 20 arranged inside the main body 13 below the base end of the lower side of the inlet section 14, and a plurality of stator vanes 21 supporting the cover 20. In this example, the cover 20 is formed in a cylindrical shape centered on the axis x as a whole. An upper surface 20a of the cover 20 bulges upward in the axial direction, for example, in a hemispherical shape. The cover 20 is arranged inside the first space S1. The plurality of stator vanes 21 connect the upper surface 20a of the cover 20 and the inner surface 14a of the inlet section 14 to each other. In this example, three stator vanes 21 are arranged at predetermined intervals in the circumferential direction. The cover 20 and the stator vanes 21 are formed integrally with the inlet section 14. Details of the stator vanes 21 will be described later.

[0017] The pump device 1 includes a shaft 22 fixed to the casing 10. In this example, the shaft 22 is formed in a cylindrical shape centered on the axis x. The upper end of the shaft 22 is fixed to a recess 20b formed in the lower surface of the cover 20. The lower end of the shaft 22 is fixed to a mounting hole 16a formed in the bottom wall 16. In this example, the recess 20b is recessed upward from the lower surface of the cover 20. In this way, the cover 20 covers the end, i.e., the upper end, of the shaft 22. Furthermore, the mounting hole 16a passes through the bottom wall 16 in the axial direction.

[0018] A rotor 30 is supported on the shaft 22 so as to be rotatable about the axis x and movable along the axis x. The rotor 30 has an impeller 31 and a magnet 32 ​​attached to the impeller 31. The impeller 31 has an impeller main body 33. The impeller main body 33 has a cylindrical portion 34, a base 35, a plurality of blades 36, and a flange 37. The impeller main body 33 is integrally formed by injection molding from a thermoplastic resin material such as PPS (polyphenylene sulfide).

[0019] The tubular portion 34 is formed in a cylindrical shape centered on the axis x. The base 35 is formed at the upper end of the tubular portion 34. The base 35 extends radially in an annular shape from the outer peripheral surface of the tubular portion 34. That is, the base 35 is formed in a disk shape centered on the axis x. In this example, the base 35 defines an upper surface that slopes downward from the inner peripheral end connected to the tubular portion 34 toward the outer peripheral end. In the axial direction, the lower surface of the base 35 faces the upper surface of the flange 37.

[0020] A plurality of (seven in this example) blades 36 are formed on the upper surface of the base 35, rising upward from the upper surface. The plurality of blades 36 are arranged in the circumferential direction. In this example, all of the blades 36 have the same shape and dimensions. Details of the blades 36 will be described later. A flange 37 extends annularly on the outer periphery. A ring-shaped recess 38 that is recessed in the radial direction is formed by the outer circumferential surface of the cylindrical portion 34 and the lower surface of the flange 37. A magnet 32 ​​is fixed to the recess 38.

[0021] In this example, magnet 32 ​​is formed in a cylindrical shape centered on axis x. The upper surface of magnet 32 ​​abuts against flange 37. Magnet 32 ​​is, for example, a permanent magnet. Magnet 32 ​​has alternating regions magnetized to south poles and regions magnetized to north poles defined in the circumferential direction around axis x. In this example, the diameter defined by the outer circumferential surface of magnet 32 ​​is set to be the same as the diameter defined by the outer circumferential surface of flange 37.

[0022] The impeller 31 is supported on the shaft 22 via a cylindrical tubular member 23 centered on the axis x. The tubular member 23 is disposed between a tubular portion 34 of the impeller 31 and the shaft 22. The tubular member 23 is supported on the shaft 22 so as to be rotatable about the axis x, and is also supported on the shaft 22 so as to be movable up and down in the axial direction. The tubular member 23 is a so-called sliding bearing. In this example, a predetermined gap is secured in the axial direction between the upper end of the tubular member 23 and the lower surface of the cover 20, and between the lower end of the tubular member 23 and the upper surface of the bottom wall 16.

[0023] The base 35 and blades 36 of the impeller 31 are housed in the first space S1, while the flange 37 and magnet 32 ​​of the impeller 31 are housed in the second space S2. In the axial and radial directions, the blades 36 of the impeller 31 face the inner surface of the main body 13 of the upper casing 12 across a predetermined gap. In the radial direction, the outer peripheral surface of the magnet 32 ​​faces the inner peripheral surface of the inner wall 17 of the lower casing 11 across a predetermined gap. In the axial direction, the lower surface of the magnet 32 ​​faces the upper surface of the bottom wall 16 of the lower casing 11 across a predetermined gap.

[0024] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. Referring to both FIGS. 2 and 3, a stator 40 is assembled into the lower casing 11. The stator 40 includes a stator core 41, a plurality of coils 42, and an insulator 43. The stator core 41 is formed from a laminate of a plurality of thin plates stacked in the axial direction. The laminate is formed from a magnetic material. The coils 42 have windings made of, for example, copper wire. The insulator 43 electrically insulates the stator core 41 from the plurality of coils 42. The insulator 43 is formed from an insulating material such as a resin material.

[0025] The stator core 41 includes an annular portion 44 fixed to the inner circumferential surface of the outer wall 19 and a plurality of teeth 45. The annular portion 44 is defined in an annular shape around the axis x. Each tooth 45 protrudes inward from the inner circumferential surface of the annular portion 44. In this example, twelve teeth 45 are arranged at equal intervals in the circumferential direction. Each tooth 45 faces the outer circumferential surface of the magnet 32 ​​of the rotor 30 with a predetermined magnetic gap between them, with the inner circumferential surface of the inner wall 17 of the lower casing 11 sandwiched therebetween. A coil 42 is wound around an insulator 43 covering each tooth 45. While the number of teeth is 12 in this embodiment, this is not limiting. The number of teeth can be any number, such as 6 or 18. The number of poles of the rotor can be changed in accordance with the change in the number of teeth.

[0026] FIG. 4 is a partially enlarged cross-sectional view of a portion of FIG. 2. FIG. 5 is a partially enlarged cross-sectional view taken along line 5-5 in FIG. 2. FIG. 6 is a perspective view schematically illustrating the structure of a cover 20 and stator vanes 21 according to one specific example. Referring to FIGS. 4 to 6 together, each stator vane 21 extends spirally along the axis x. As shown in FIG. 5, in this example, three stator vanes 21 are arranged at equal intervals around the axis x. A radius d1 defined by the inner surface 14a of the inlet section 14 is larger than a radius d2 defined by the outer surface 20c of the cover 20. In this example, an imaginary plane P1 including the upper end of each stator vane 21 and the axis x and an imaginary plane P2 including the lower end of each stator vane 21 and the axis x intersect with each other at an angle α of approximately 90 degrees.

[0027] Each stator vane 21 has an upper portion 25 arranged axially upward and a lower portion 26 arranged axially downward. The upper portion 25 and the lower portion 26 are integrally formed with each other. As shown in FIG. 4 , the upper portion 25 is arranged within the inlet portion 14. The lower portion 26 is arranged within the small diameter portion 13a of the main body 13. The outer peripheral end of the upper portion 25 of each stator vane 21 is connected to the inner surface 14a of the inlet portion 14, while the lower end of the lower portion 26 is connected to the upper surface 20a of the cover 20.

[0028] Each stator vane 21 has a first blade surface 27 facing upward in the axial direction and a second blade surface 28 facing downward in the axial direction. In FIG. 5 , only the first blade surface 27 of each stator vane 21 can be seen. The first blade surface 27 is a curved surface twisted around the axis x. The first blade surface 27 is formed by a curved first surface 27a facing the inner surface 14a of the inlet section 14 and a curved second surface 27b facing the blades 36 of the impeller 31. In other words, the first surface 27a and the second surface 27b form a continuous surface.

[0029] FIG. 7 is a perspective cross-sectional view taken along line 7-7 in FIG. 2. FIG. 8 is a partially enlarged cross-sectional view taken along line 8-8 in FIG. 2. Referring to both FIGS. 7 and 8, the base 35 of the impeller 31 has an inner peripheral edge 35a and an outer peripheral edge 35b. Each blade 36 extends in a generally radial direction while curving from edge 35a to edge 35b. Specifically, each blade 36 curves in an arc in the clockwise direction as it approaches edge 35b. In this example, as shown in FIG. 4, the upper end faces of all the blades 36 are defined in the same plane. Each blade 36 constitutes a rotor blade in the pump device 1.

[0030] Each blade 36 has, at its inner peripheral end, an inclined surface 36a that moves away from the axis x toward the outer periphery as it moves axially upward. This inclined surface 36a is inclined so as to face the portion of the lower portion 26 of the stator vane 21 that faces the outer periphery. As shown in FIG. 5 , the inclined surface 36a on the inner peripheral side of each blade 36 can be seen in the inlet section 14 in the axial direction. That is, each stator vane 21 faces multiple blades 36 in the axial direction. In this example, the inclined surfaces 36a of all the blades 36 are defined within a hemispherical truncated surface centered on the axis x.

[0031] In this pump device 1, when current is supplied to the coil 42 of the stator 40, magnetic interaction between the coil 42 and the magnet 32 ​​causes the rotor 30, i.e., the impeller 31, to rotate counterclockwise around the axis x. This rotation causes the coolant to flow into the first space S1 from the inlet portion 14. At this time, the coolant flows from the first surface 27a to the second surface 27b of the first blade surface 27 of each of the three stator vanes 21, as shown by arrows A1 in Fig. 5. Because the first surface 27a and the second surface 27b are twisted curved surfaces, a swirling component about the axis x is imparted to the coolant.

[0032] A plurality of blades 36 face the outer periphery of the lower portion 26 of the stator vane 21. As a result, the coolant to which a swirl component has been imparted flows from the upper surface 20a of the cover 20 into the spaces between the plurality of blades 36 rotating around the axis x, as shown by arrows A2 in Figure 8. In this way, a curved flow path A2 for the coolant is formed by the first surface 27a and second surface 27b of the stator vane 21 and the plurality of blades 36. Because the stator vane 21 is fixed while the plurality of blades 36 rotate around the axis x, a pair of blades 36, 36 forming the curved flow path A2 for the coolant alternates for each stator vane 21.

[0033] The coolant that flows along the curved flow path A2 between each pair of circumferentially adjacent blades 36, 36 flows out further toward the outer periphery from the outer peripheral edge 35b of the base 35 of the impeller 31. The coolant then flows counterclockwise along the inner circumferential surface of the small diameter portion 13a of the main body 13 of the upper casing 12, and then flows out from the outlet 15. In this way, the rotation of the rotor 30, i.e., the impeller 31, about the axis x causes the coolant to be pumped from the pump device 1 to, for example, a driving source.

[0034] In the pump device 1 described above, each stator vane 21 has a first blade surface 27 that is a twisted curved surface. The coolant that has flowed into the inlet section 14 flows along the first blade surface 27 of each stator vane 21, imparting a swirling component about the axis x to the coolant. The coolant to which the swirling component has been imparted smoothly flows between the multiple blades 36 that face the outer periphery of the stator vane 21. As a result, the coolant is prevented from colliding linearly with the upper surface 20a of the cover 20 and the inlet section 14, allowing the coolant to flow more smoothly than before. This improves the efficiency of the pumping performance of the pump device 1.

[0035] 9 and 10 are plan views schematically showing the structure of a stator vane 21 according to another specific example. In the example of Fig. 9, the angle α at which an imaginary plane P1 including the upper end of each stator vane 21 and the axis x intersects with an imaginary plane P2 including the lower end of each stator vane 21 and the axis x is set to approximately 60 degrees. In the example of Fig. 10, the angle α at which an imaginary plane P1 including the upper end of each stator vane 21 and the axis x intersects with an imaginary plane P2 including the lower end of each stator vane 21 and the axis x is set to approximately 45 degrees. Other components similar to those described above are designated by the same reference numerals, and redundant description will be omitted here.

[0036] FIG. 11 is a graph showing the efficiency of the pump device calculated by fluid analysis. To verify the efficiency of the pump device, fluid analysis was performed on one comparative example and three specific examples. In the comparative example, the angle α between the upper and lower ends of the stator vane was set to 0 degrees. That is, the stator vane was formed linearly along the axis x. In the three specific examples, the angle α was set to 45 degrees, 60 degrees, and 90 degrees, as shown in FIGS. 5, 9, and 10, respectively. That is, in the specific examples, the stator vane was formed spirally around the axis x. For these one comparative example and three specific examples, the fluid flow efficiency was analyzed when coolant was introduced from the inlet at a constant flow rate.

[0037] As shown in Fig. 11, in the comparative example, the efficiency, which is approximately A%, was improved to approximately close to B% in all three specific examples (where A < B). This improvement in efficiency is due to the fact that in the comparative example, the coolant flows straight from the inlet portion towards the impeller, while in the specific examples, a swirling component is imparted to the coolant by the twisted curved surfaces of each stator blade 21, thereby reducing the collision loss against the upper surface 20a of the cover 20. Also, since there is little difference in efficiency among the three specific examples, it was found that the efficiency is improved by setting the angle α to at least 45 degrees to 90 degrees.

[0038] As described above, the present invention has been described through the above embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0039] The embodiments described above are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Also, the above embodiments do not limit the objects to which the present invention is applied, and the present invention can include any object as its application object. Each component included in the above embodiments, as well as its arrangement, material, conditions, shape, size, etc., are not limited to those illustrated and can be changed as appropriate. For example, the present invention includes differences that occur in the implementation of manufacturing tolerances, etc. Also, within a technically non - conflicting range, components shown in different embodiments can be partially replaced or combined with each other. Also, each configuration can be appropriately and selectively combined so as to achieve at least part of the above - described problems and effects.

Explanation of Reference Numerals

[0040] 1 pump device, 10 casing, 11 lower casing, 12 upper casing, 13 main body, 13a small diameter portion, 13b large diameter portion, 14 inlet portion, 14a inner surface, 15 outlet portion, 16 bottom wall, 16a mounting hole, 17 inner wall, 18 top wall, 19 outer wall, 20 cover, 20a upper surface, 20b recess, 21 stator blade, 22 shaft, 23 tubular member, 25 upper portion, 26 lower portion, 27 first blade surface, 27a first surface, 27b second surface, 28 second blade surface, 30 rotor, 31 impeller, 32 magnet, 33 impeller main body, 34 tubular portion, 35 base, 35a, 35b edge portion, 36 blade, 36a inclined surface, 37 flange, 38 recess, 40 Stator, 41 stator core, 42 coil, 43 insulator, 44 annular portion, 45 teeth, P1 virtual plane, P2 virtual plane, S internal space, S1 first space, S2 second space, x axis

Claims

1. A shaft, an impeller supported by the shaft; a fluid inlet; an outlet for the fluid; a cover that covers the end of the shaft; a plurality of stator vanes connecting the inlet portion and the cover; A pump device comprising:

2. the stator vane includes a curved first surface facing the inner surface of the inlet section; 2. The pump device of claim 1.

3. the stator vane has a curved second surface facing the impeller; 3. A pump device according to claim 1 or 2.

4. the stator vane includes a twisted curved surface formed by the first surface and the second surface.

4. The pump device according to claim 3.

5. The first surface and the second surface form a continuous surface.

5. The pump device according to claim 3 or 4.

6. The stator vanes and the impeller blades can form a curved flow path.

2. The pump device of claim 1.

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