Impeller and submersible pump

Abstract

To provide an impeller and a submersible pump capable of enhancing welding strength of a vane and a shroud.SOLUTION: An impeller 42 includes: a main plate 101 formed of resin material, and having a back shroud 52 fixed to a rotating shaft 24 and a vane 54 integrally formed with the back shroud 52; and a side plate 102 including a front shroud 53 having a suction port 58, a weld groove 105 provided on a rear surface of the front shroud 53 and recessed in the shape of an end of the vane 54 to which the end of the vane 54 is inserted, and a guide wall 107 arranged adjacent to at least a part of the weld groove 105 in a width direction of the weld groove 105 and having an outer surface along the vane 54 in the weld groove 105 side, wherein front and back surfaces of the vane 54 are welded to the front shroud 53 in a state where the vane 54 is arranged in the weld groove 105.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to an impeller and a submersible pump for pumping sewage or the like. [Background technology]

[0002] Submersible pumps used to pump wastewater, etc., are centrifugal pumps with an impeller housed in a spiral-shaped casing. In such submersible pumps, for example, as the impeller rotates, wastewater is sucked in through a suction port provided on the bottom surface of the casing and discharged from a discharge port provided on the side surface of the casing.

[0003] Submersible pumps used to transport such sewage and the like are required to be designed to reliably discharge the sewage contained in them in order to prevent malfunctions caused by foreign matter contained in the sewage getting caught in the rotating shaft, impeller, etc.

[0004] For this reason, for example, a so-called semi-open impeller having a plurality of blades on a single shroud is used as the impeller, but since this type of impeller has poor pump efficiency, a closed impeller is known that is used when high efficiency is required.

[0005] Such a closed impeller has blades provided between two shrouds, and is more likely to have foreign matter caught in the impeller than a semi-open impeller.

[0006] For this reason, in order to prevent the entrainment of foreign matter, an impeller having one blade between shrouds is known as a closed non-clog impeller (see, for example, Patent Document 1). Such an impeller is manufactured by casting from gray cast iron or stainless cast steel.

[0007] However, the above-mentioned impeller is manufactured by casting, which may result in a rough surface, which may reduce the pump efficiency. In addition, the impeller made of gray cast iron needs to be painted to prevent rust, which increases the manufacturing cost.

[0008] Impellers made from cast stainless steel can be difficult to procure due to the time required to manufacture them, and because such impellers are made from a material with a high specific gravity, they also have the problem of needing to be mechanically balanced when rotating.

[0009] Therefore, it is also conceivable to mold the closed non-clog impeller from a resin material. For example, as a method for manufacturing an impeller from a resin material, a technique is known in which a front shroud and a rear shroud on which a plurality of blades are formed are molded separately (for example, see Patent Document 2). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2012-77671 A [Patent Document 2] Patent No. 6006987 Summary of the Invention [Problem to be solved by the invention]

[0011] The impeller of Patent Document 2 requires different ultrasonic welding processes for the welding rib provided at the center of the blade and the rivet rib, which increases the number of processes and can be a factor in increasing costs. Also, the impeller of Patent Document 2 has a welding rib provided at the center of the blade, and is configured with multiple blades arranged at equal intervals, so the welding strength can be sufficiently ensured.

[0012] However, closed non-clog impellers have a small number of blades, one or at most two. With fewer blades, the welding surface with the shroud is reduced, which may result in insufficient strength of the welded impeller.

[0013] Furthermore, if the molded blades are inclined with respect to the specified shape, there is a risk that they will not be positioned in the specified position on the shroud, and there is a risk that the specified welding strength will not be obtained.

[0014] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an impeller and a submersible pump that can improve the welding strength between the blades and the shroud. [Means for solving the problem]

[0016] According to one aspect of the present invention, an underwater pump includes a motor, a pump casing, a rotating shaft having one end connected to the motor and the other end disposed within the pump casing, a rear shroud formed of a resin material and fixed to the rotating shaft, a main plate having blades integrally molded with the rear shroud, and a front shroud having a suction port, an impeller provided on a rear surface of the front shroud and into which tips of the blades are inserted, the impeller having a welding groove recessed in the shape of the tip of the blade, and a side plate disposed adjacent to at least a portion of the welding groove in a width direction of the welding groove and having an outer surface along the blade on the welding groove side, and the front and back surfaces of the tips of the blades are welded to the front shroud with the blades disposed in the welding groove. The blades extend along the axial direction, an outer surface of the guide wall on the welding groove side extends along the axial direction and is formed in the same shape as the opposing outer surface of the blade, and the width of the guide wall gradually narrows from the back surface side of the front shroud toward the tip. Effect of the Invention

[0017] According to the present invention, it is possible to provide an impeller and a submersible pump that can improve the welding strength between the blades and the shroud. [Brief description of the drawings]

[0018] [Figure 1] 1 is an explanatory diagram showing, in partial cross section, the configuration of a submersible pump according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a cross-sectional view showing the configuration of the impeller of the submersible pump. [Diagram 3] FIG. 4 is a perspective view showing a configuration of a main plate of the impeller. [Figure 4] FIG. 4 is a perspective view showing a configuration of a side plate of the impeller. [Diagram 5] FIG. 4 is a perspective view showing a configuration of a protrusion provided on the side plate. [Figure 6] 4A to 4C are explanatory views showing a main configuration of the impeller and an example of a method of manufacturing the impeller. [Figure 7] FIG. 4 is an explanatory diagram showing an example of a method for manufacturing the impeller, illustrating an exploded view of the main plate and side plate that constitute the impeller; [Figure 8] 4 is an explanatory diagram showing the configuration of the main plate and side plate of the impeller, and showing an example of a manufacturing method of the impeller. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, a submersible pump 1 and an impeller 42 according to one embodiment of the present invention will be described with reference to Figs. Figure 1 is an explanatory diagram showing, in partial cross section, the configuration of an underwater pump 1 according to one embodiment of the present invention, Figure 2 is a cross-sectional view showing the configuration of an impeller 42 of the underwater pump 1, taken along line II-II in Figure 1, Figure 3 is an oblique view showing the configuration of a main plate 101 of the impeller 42, Figure 4 is an oblique view showing the configuration of a side plate 102 of the impeller 42, and Figure 5 is an oblique view showing the configuration of a protrusion 106 provided on the side plate 102.

[0020] Figure 6 is an explanatory diagram showing the configuration of the ends of the blades 54 of the impeller 42 used in the underwater pump 1 and the welding grooves 105 of the front shroud 53, and also showing an example of the manufacture of the impeller 42. Figure 7 is an explanatory diagram showing an exploded view of the configuration of the main plate 101 and side plate 102 that constitute the impeller 42, and also showing an example of the manufacture of the impeller 42. Figure 8 is an explanatory diagram showing the main configuration of the main plate 101 and side plate 102 of the impeller 42, and also showing an example of the manufacture of the impeller 42. It is.

[0021] 1, the submersible pump 1 includes a motor 10, a shaft sealing device 11, a pump 12, and a connecting pipe 13. Such a submersible pump 1 is a so-called submersible sewage pump that is installed in a sewage tank, a sewer system, or the like, and pumps sewage that contains foreign matter (such as sewage).

[0022] The motor 10 includes a motor casing 21, a stator 22, a rotor 23, and a rotating shaft 24. The motor 10 also has a plurality of bearings 25 that rotatably support the rotating shaft 24, and a power cable 26 that connects the stator 22 to an external power source or the like. The motor casing 21 is formed in a cylindrical shape with both ends closed, and one end face is fixed to the shaft seal device 11 with a bolt or the like.

[0023] The stator 22 is fixed to the inner surface of the motor casing 21. The stator 22 is formed so as to be able to rotate the rotor 23 by power supplied via a power cable 26. The rotor 23 is fixed to the rotating shaft 24 so as to be able to rotate the rotating shaft 24 in accordance with the rotation of the rotor 23.

[0024] The rotating shaft 24 protrudes from one end of the motor casing 21 and is rotatably supported by the motor casing 21 via a bearing 25. The rotating shaft 24 extends from the motor casing 21 in the direction of gravity when the submersible pump 1 is installed on an installation surface.

[0025] The shaft seal device 11 includes a seal casing 30 and a mechanical seal 31. The shaft seal device 11 provides a liquid-tight partition between the motor 10, the pump 12, and the rotating shaft 24.

[0026] The seal casing 30 is formed so as to be capable of housing the mechanical seal 31 therein. Such a seal casing 30 is formed in a cylindrical shape with both ends closed, and an insertion hole 33 into which the rotating shaft 24 is inserted is formed on both end faces. The seal casing 30 also forms an oil chamber 34 therein that can be filled with lubricating oil for the mechanical seal 31. For example, the seal casing 30 is made up of two components separated in the axial direction, and the oil chamber 34 is formed therein by assembling them together.

[0027] The mechanical seal 31 seals the gap between the seal casing 30 and the rotating shaft 24, thereby preventing the infiltration of sewage from the pump 12 and the infiltration of lubricating oil into the motor 10.

[0028] The pump 12 includes a casing 41 and an impeller 42. The casing 41 is a spiral casing that houses the impeller 42 therein, and defines a pump chamber 43 therein. The casing 41 is made up of a plurality of components, and the pump chamber 43 is defined therein by assembling the components.

[0029] The casing 41 has a plurality of legs 48 for mounting the submersible pump 1 on an installation surface. The casing 41 also has a suction opening 49 provided on the bottom surface and between the plurality of legs 48, and a discharge opening 50 provided on a part of the side surface.

[0030] The suction opening 49 is formed to have approximately the same diameter as a suction port 58 (described later) of the impeller 42. The suction opening 49 may have a liner ring that rotatably supports the impeller 42.

[0031] The discharge opening 50 is formed such that its aperture (discharge diameter) allows passage of foreign matter having a particle size that can pass through the impeller 42. Specifically, the aperture of the discharge opening 50 is formed to be approximately the same diameter as foreign matter of a predetermined particle size that can pass through the impeller 42. Here, foreign matter of a predetermined particle size that can pass through the impeller 42 is, for example, a spherical solid object having the same diameter (predetermined particle size) as the aperture (discharge diameter) of the discharge opening 50 of the submersible pump 1.

[0032] 1 to 4 and 7, the impeller 42 is a closed non-clog impeller that is formed to be able to pass foreign matter of a predetermined particle size. Such an impeller 42 includes a back shroud 52 disposed on the shaft seal device 11 side, a front shroud 53 disposed opposite the back shroud 52 and disposed on the suction opening 49 side, and vanes 54 disposed between the shrouds 52 and 53.

[0033] The impeller 42 also has a suction port 58 provided in the front shroud 53 for sucking in a fluid, and a discharge port 59 formed by the rear shroud 52, the front shroud 53, and the blades 54 and for discharging the sucked in fluid. In the impeller 42, the rear shroud 52, the front shroud 53, and the blades 54 are molded from a resin material.

[0034] The resin material constituting the impeller 42 is, for example, a polyamide resin. The polyamide resin is preferably a low water-absorbent polyamide resin having more than 6 carbon atoms in one unit. The polyamide resin is preferably a semi-aromatic polyamide resin.

[0035] The rear shroud 52 is formed in a disk shape. An insertion hole 52a having a key groove into which the rotating shaft 24 can be inserted is formed at the center of the rear shroud 52. Note that the insertion hole 52a can, for example, be formed by inserting an insert member into the rear shroud 52, into which the rotating shaft 24 can be firmly fixed and in which a key groove is formed for improving strength, and into which the rotating shaft 24 can be fixed. When the impeller 42 is fixed to the rotating shaft 24, the rear shroud 52 is located above the front shroud 53 in the direction of gravity.

[0036] The front shroud 53 is formed in an annular shape. The front shroud 53 has a suction port 58 formed at its center. The suction port 58 protrudes from the front surface side of the front shroud 53 in a cylindrical shape, for example.

[0037] The blade 54 is provided integrally between the rear shroud 52 and the front shroud 53. As shown in Figures 2 and 3, the blade 54 includes a first blade 61, a second blade 62, and a third blade 63. The blade 54 also configures a connecting wall 64 that connects one end side of the first blade 61, an end portion of the second blade 62 on the suction port 58 side, and an end portion of the third blade 63 on the suction port 58 side.

[0038] For example, the first blade 61, the second blade 62, and the third blade 63 are curved in the longitudinal direction with different radii of curvature and extend from the radial direction toward the outer circumferential edge of the shrouds 52, 53. In addition, for example, the first blade 61, the second blade 62, and the third blade 63 are formed to have the same thickness.

[0039] One end (connecting wall 64) of the first blade 61 is disposed on the center side of the shrouds 52, 53 and on the periphery of the suction port 58 of the front shroud 53, and the other end is disposed on the outer periphery of the shrouds 52, 53. More specifically, the first blade 61 is disposed on the periphery of the suction port 58 from one end toward the center, and the portion from the center to the other end moves away from the suction port 58 and curves with a predetermined radius of curvature to extend to the outer periphery of the shrouds 52, 53. The first blade 61 is integrally formed with the second blade 62 and the third blade 63 by the connecting wall 64 formed by the end on one side.

[0040] The second blade 62 has one end on the suction port 58 side integrally formed with the first blade 61 on the suction port 58 side. The second blade 62 is provided between the suction port 58 and the first blade 61 with a gap between the first blade 61 and the second blade 62, and extends from the suction port 58 toward the outer circumferential edge side of the shrouds 52, 53. The second blade 62 has an end on the outer circumferential edge side of the shrouds 52, 53 spaced apart from the outer circumferential edge of the shrouds 52, 53. As a specific example, the second blade 62 is provided branching off from the inner circumferential surface of the connecting wall 64, in other words, from the inner circumferential surface on the central side of one end side of the first blade 61. The end of the second blade 62 on the first blade 61 side is disposed on the periphery of the suction port 58, and the other end side from the central side is away from the suction port 58 and curved with a predetermined radius of curvature. The second blade 62 is disposed opposite a part of the first blade 61 and an inner peripheral surface of the first blade 61 at a predetermined distance, with one end being integral with the first blade 61 and the other end being spaced apart from the first blade 61. The second blade 62 is disposed opposite the first blade 61 so that the internal flow path from the suction port 58 inside the impeller 42 changes constantly.

[0041] The third blade 63 is formed in an asymmetric shape with respect to each of the first blade 61 and the second blade 62. The third blade 63 is provided branching off from the end of the connecting wall 64, in other words, from the outer peripheral surface side of the end of the first blade 61 on the suction port 58 side. The third blade 63 extends from the suction port 58 toward the outer peripheral edge side of the shrouds 52, 53, and the end on the outer peripheral edge side of the shrouds 52, 53 is separated from the outer peripheral edge of the shrouds 52, 53. The third blade 63 is provided at a symmetrical position with respect to the first blade 61 around the axis of the shrouds 52, 53. Here, the symmetrical position includes a substantially symmetrical position.

[0042] The connecting wall 64 is provided between the rear shroud 52 and the front shroud 53, radially facing the third blade 63, and is constituted by the end portion of the first blade 61 on the suction port 58 side. The connecting wall 64 connects the first blade 61, the end portion of the second blade 62 on the suction port 58 side, and the end portion of the third blade 63 on the suction port 58 side along the edge of the suction port 58. In other words, the connecting wall 64 forms one flow path for the water sucked from the suction port 58 from between the ends of the second blade 62 and the third blade 63 on the suction port 58 side toward the outer circumferential edge of the shrouds 52, 53.

[0043] In the impeller 42 thus configured, the end of the third blade 63 on the suction port 58 side and the end of the second blade 62 on the suction port 58 side are integrally formed with the end side (connecting wall 64) of the first blade 61. With this configuration, the impeller 42 forms a flow path from the suction port 58 through the inner peripheral surface of one end side (connecting wall 64) of the first blade 61 and between the end of the third blade 63 toward the discharge port 59, and pumps water through the outer peripheral surface of the first blade 61 and the outer peripheral surface of the third blade 63 during rotation. That is, the impeller 42 configures a so-called 1.5-blade non-clog impeller with the first blade 61 and the third blade 63. In addition, the second blade 62 of the impeller 42 keeps the amount of change in the flow path cross-sectional area of ​​the flow path from the suction port 58 to the discharge port 59 approximately constant, suppressing excessive change in the flow path cross-sectional area.

[0044] Further, the thickness of the end of the first blade 61 (connecting wall 64) and the third blade 63 on the suction port 58 side, and the portion where the first blade 61 (connecting wall 64) on the suction port 58 side and the end of the second blade 62 on the suction port 58 side are integrally formed is made thicker than the thickness of the first blade 61, the second blade 62, and the third blade 63. That is, the blade 54 has a thick portion 54a in a part. In this embodiment, the blade 54 has the thick portion 54a configured to be thicker than other portions in two continuous portions of the first blade 61 and the third blade 63, and the first blade 61 and the second blade 62.

[0045] As a specific example, such an impeller 42 is formed by welding together, as shown in Figures 3, 4, and 6 to 8, a main plate 101 in which the rear shroud 52 and the blades 54 are integrally molded from a resin material by injection molding, and a side plate 102 in which the front shroud 53 is molded from a resin material by injection molding.

[0046] As shown in FIG. 3, the main plate 101 is formed in a shape having the rear shroud 52, the blades 54, and at least one hole 104 formed in an end surface of the blades 54.

[0047] The holes 104 are set at a predetermined depth from the end face of the blade 54. The holes 104 are used for circumferential alignment of the main plate 101 and the side plate 102. For example, a plurality of holes 104 may be provided. At least some of the plurality of holes 104 are provided in the end faces of the thick portions 54a of the blades 54. In this embodiment, the blades 54 have the thick portions 54a in two locations. Also, in this embodiment, the plurality of holes 104 are configured to be provided in three locations on the end faces of the blades 54.

[0048] For this reason, in this embodiment, two of the three holes 104 are disposed in the thick portion 54a of the blade 54. To explain a specific example, the two holes 104 are formed in the end faces of the thick portion 54a at two locations where the ends of the first blade 61 and the third blade 63 on the suction port 58 side and the end of the second blade 62 on the suction port 58 side are integrally formed with the end side (connecting wall 64) of the first blade 61. The remaining hole 104 is provided at a position as equally spaced as possible from the other two holes 104, and therefore, to explain a specific example, it is provided in the end face on the end side opposite to the thick portion 54a in the extension direction of the second blade 62.

[0049] As shown in FIG. 4 , the side plate 102 has a front shroud 53, a welding groove 105 formed on the back surface of the front shroud 53 facing the rear shroud 52, protrusions 106 provided in the welding groove 105 and the same number as the holes 104, and one or more guide walls 107 provided adjacent to a portion of the welding groove 105 in the width direction of the welding groove 105.

[0050] The welding groove 105 is formed in a shape that allows the end of the blade 54 to be inserted and disposed therein. That is, the width of the welding groove 105 on the back surface side of the front shroud 53 is set to be the same as the width of the blade 54 or slightly larger than the width of the blade 54 so that the blade 54 can be inserted and disposed therein. In other words, the welding groove 105 is formed on the back surface side of the front shroud 53 in a shape that is the same as the end face of the blade 54 or slightly larger than the end face of the blade 54. As a specific example, the welding groove 105 has a first groove 105a and a second groove 105b that is formed on the bottom surface of the first groove 105a and has a narrower width than the first groove 105a.

[0051] Here, the width of the blade 54 and the width of the welding groove 105 (first groove 105a, second groove 105b) are the direction perpendicular to the extension direction of the blade 54 and the welding groove 105, and the direction in which the front and back surfaces of the blade 54 face each other.

[0052] Here, the back surface of the blade 54 refers to the main surface on the center side in the radial direction along the extension direction of the blade 54, and the front surface of the blade 54 refers to the main surface on the outer side in the radial direction. In other words, the back surface of the blade 54 is the primary side surface in the rotation direction of the impeller 42, and the front surface of the blade 54 is the secondary side surface in the rotation direction of the impeller 42. Therefore, the front surface of the blade 54 is the surface that presses water against the blade 54 when the impeller 42 rotates.

[0053] 6, when the width (thickness) of the blade 54 is T1, the width of the first groove 105a is T2, and the width of the second groove 105b is T3, they are set to have a relationship of T2>T1>T3. That is, in consideration of the insertion (fitting) of the blade 54 into the welding groove 105 and the dimensional accuracy, it is preferable that the width T2 of the first groove 105a is set larger than the width T1 of the blade 54.

[0054] The dimensional difference (gap) between the width T1 of the blade 54 and the width T2 of the first groove 105a is set to a dimensional difference that allows the blade 54 to be aligned with the welding groove 105 and does not cause a decrease in the performance of the impeller 42 due to the resulting gap. More preferably, the dimensional difference (gap) between the width T1 of the blade 54 and the width T2 of the first groove 105a is set to a dimensional difference that prevents foreign matter or dirt contained in the sewage from getting caught. The dimensional difference is set appropriately depending on the accuracy of the molding technology (injection molding), the environment in which the submersible pump 1 (impeller 42) is used, the required performance, and the like. Here, setting depending on the environment in which the submersible pump 1 is used includes setting the dimensional difference to a dimensional difference that prevents foreign matter or dirt from getting caught or accumulating in the gap between the blade 54 and the first groove 105a in the case of a sewage pump that pumps water containing foreign matter or dirt.

[0055] The first groove 105a is formed in the shape of the axial end surface of the blade 54. The end of the blade 54 is inserted into the first groove 105a, thereby enabling the alignment of the blade 54. For this reason, the width of the first groove 105a is set to be the same as the width of the blade 54 or slightly larger than the width of the blade 54.

[0056] The second groove 105b forms a space for penetration into which a part of the molten blades 54 and the side plate 102 (front shroud 53) of the main plate 101 flows when the blades 54 inserted in the first groove 105a and the side plate 102 (front shroud 53) are welded together. The second groove 105b is set to have a width smaller than that of the blades 54.

[0057] Protrusion 106 is provided within welding groove 105. The multiple protrusions 106 are provided at positions where they can be inserted into multiple holes 104 provided in blade 54 when blade 54 is placed in welding groove 105. As a specific example, protrusion 106 is provided on the bottom surface of second groove 105b. Note that when the width of second groove 105b is smaller than the outer diameter of protrusion 106, protrusion 106 is provided across first groove 105a and second groove 105b.

[0058] The protrusion 106 is formed in a cylindrical shape with a diameter equal to or slightly smaller than the inner diameter of the hole 104. The tip of the protrusion 106 is formed with a small diameter to guide the insertion into the hole 104. As a specific example, as shown in FIG. 5, the protrusion 106 is formed in a cylindrical shape with a semicircular tip. As shown in FIG. 5, the protrusion 106 has ribs 106a at multiple locations on the outer circumferential surface, for example, at four locations in the circumferential direction. The ribs 106a are formed in triangular plate shapes provided at the corners between the bottom surface of the second groove 105b and the outer circumferential surface of the protrusion 106.

[0059] In the embodiment, the guide wall 107 is disposed adjacent to at least a part of the welding groove 105 in the width direction of the welding groove 105, and has an outer surface along the outer surface of the blade 54 on the welding groove 105 side. The guide wall 107 abuts against a part of the outer surface of the blade 54. The outer surface of the guide wall 107 abutting against the blade 54 is formed in a curved shape with the same curvature as the curvature of the blade 54. In addition, the outer surface of the guide wall 107 abutting against the blade 54 extends in the same direction as the extension direction of the blade 54 of the predetermined shape of the impeller 42. When the blade 54 of the impeller 42 has a shape that extends along the axial direction of the impeller 42, the outer surface of the guide wall 107 abutting against the blade 54 extends along the axial direction of the impeller 42 (front shroud 53).

[0060] The width of the guide wall 107 gradually narrows from the back surface side of the front shroud 53 toward the tip. For example, the outer surface of the guide wall 107 opposite to the outer surface that abuts against the blades 54 (opposite in the width direction) is formed in a curved shape. As a specific example, the outer surface of the guide wall 107 opposite to the outer surface that abuts against the blades 54 is curved along the extension direction of the welding groove 105, and is curved in an arc shape or quarter circle shape with a predetermined curvature in which a tangent is inclined to the axial direction in a cross-sectional shape perpendicular to the longitudinal direction. The height of the guide wall 107 from the back surface of the front shroud 53 is set to a height smaller than half the axial length (height) of the blades 54. This is to reduce loss of the impeller 42 and to prevent the impeller 42 from affecting the foreign object passing diameter (particle size) of the foreign object that can pass through the impeller 42.

[0061] The guide wall 107 is provided in the width direction of the welding groove 105 and adjacent to at least a part of the extension direction of the welding groove 105, preferably adjacent to at least a part of the end side in the extension direction of the welding groove 105. For example, the guide wall 107 is provided in the width direction of the welding groove 105, on the back side of the blade 54, and on the end side of the welding groove 105.

[0062] 8, for example, two guide walls 107 are provided. One of the guide walls 107 is provided at an end of the first groove 105a on the back side of the first blade 61 and located on the outer circumferential edge side of the front shroud 53. The other guide wall 107 is provided at an end of the first groove 105a on the back side of the third blade 63 and located on the main surface side of the front shroud 53.

[0063] The connecting pipe 13 is connected to the discharge opening 50. The connecting pipe 13 is, for example, a bent pipe that bends 90 degrees upward from the discharge opening 50. The connecting pipe 13 has, for example, a leg portion 13a.

[0064] Next, a manufacturing method for the impeller 42 configured as above will be described with reference to FIG. First, as shown in step ST1 in Fig. 6, the main plate 101 and the side plate 102 which are the front shroud 53 and in which the rear shroud 52 and the blades 54 are integrally formed are molded by injection molding. Then, as shown in step ST1 in Fig. 6 and Fig. 7, the blades 54 are disposed to face the welding grooves 105 formed in the front shroud 53.

[0065] 6, the blade 54 of the main plate 101 is placed in the first groove 105a of the side plate 102. At this time, the front and back surfaces of the blade 54 are aligned with the first groove 105a, and the blade 54 is inserted (fitted) into the first groove 105a, and the protrusions 106 facing each hole 104 are inserted. At this time, if the tip of the blade 54 is located radially inward from the predetermined shape (deformed), the guide wall 107 guides the blade 54 to the predetermined shape. As a result, the blade 54, which has been deformed from the predetermined shape, is guided to the predetermined shape and is fitted into the first groove 105a in the predetermined shape.

[0066] Next, as in step ST3 shown in Fig. 6, the blades 54 are welded to the front shroud 53 (side plate 102) by ultrasonic welding or the like that generates frictional heat by ultrasonic vibration. At this time, the front and back surfaces of the tip of the blades 54 and both sides in the width direction of the first grooves 105a are welded. At this time, as shown in Fig. 6, the inner side and bottom surface of the first grooves 105a and the front and back surfaces and end surfaces of the blades 54 are melted together. The blades 54 and the guide walls 107 may be further welded.

[0067] 6, for example, the penetration amount in the axial direction is set to a range shallower than the depth of the first groove 105a. Through these steps, the impeller 42 is formed.

[0068] Although the impeller 42 has been described as an example in which the rear shroud 52 and the vanes 54 are integrally molded by injection molding, for example, the rear shroud 52 and the vanes 54 may be separately molded by injection molding. In this case, the rear shroud 52 may also be provided with the first groove 105a and the second groove 105b, and the rear shroud 52 and the vanes 54 may be welded together. In addition, the impeller 42 may be provided with a hole 104 at an end of the vane 54 facing the rear shroud 52, and a protrusion 106 may be provided on the bottom surface of the second groove 105b of the rear shroud 52. In addition, the impeller 42 may be provided with one or more guide walls 107 provided adjacent to a part of the welding groove 105 in the width direction of the welding groove 105 of the rear shroud 52. Also, the front shroud 53 and the vanes 54 may be integrally molded by injection molding. However, from the viewpoint of the shape of the impeller 42 and reducing the number of manufacturing steps, it is preferable to form the impeller 42 as a single unit by welding the two components, the main plate 101 and the side plate 102, as described above.

[0069] With the impeller 42 and submersible pump 1 configured in this manner, the impeller 42 is made of a resin material, which reduces surface roughness compared to impellers made of metal materials, making it possible to smooth the surface of the impeller 42. This makes it possible to reduce water resistance and friction when the submersible pump 1 is operating, thereby improving pump efficiency.

[0070] The impeller 42 can be easily manufactured because the main plate 101 and the side plate 102 are integrally molded by welding. The impeller 42 has a welding groove 105 having a first groove 105a and a second groove 105b on one main surface (back surface) of the front shroud 53 of the side plate 102, and a guide wall 107 for guiding the tip of the blade 54 in a part adjacent to the first groove 105a. When the tip of the blade 54 is inserted into the first groove 105a, and when the blade 54 is deformed from a predetermined shape, the guide wall 107 presses the blade 54 into the predetermined shape during the insertion, guiding the blade 54 into the first groove 105a. The impeller 42 is integrally molded by welding the blade 54 and the first groove 105a. Moreover, the front shroud 53 and the blades 54 are fixed by welding the front and back surfaces of the blades 54 to the inner surfaces of the first grooves 105a.

[0071] In this manner, when the blades 54 are deformed from the predetermined shape, in the example of this embodiment, when the blades 54 are deformed radially inward, the guide wall 107 presses the blades 54 to bias the tip of the impeller 42, thereby restoring the shape of the impeller 42 to the predetermined shape. That is, the guide wall 107 can correct the impeller 42, which has been deformed from the predetermined shape, to the predetermined shape. Therefore, the blades 54 guided by the guide wall 107 are suitably fitted into the first grooves 105a, and the front shroud 53 and the blades 54 can be suitably welded together. Therefore, the front shroud 53 and the blades 54 are reliably welded together, and therefore the weld strength can be improved and the occurrence of variations in the weld strength during manufacturing can be suppressed, making it possible to stabilize the quality of the manufactured product.

[0072] Furthermore, by providing the guide wall 107 on the back surface side of the blade 54, the impeller 42 can improve the strength against the force directed from the front surface to the back surface of the blade 54. That is, when the impeller 42 rotates and the front surface of the blade 54 presses water, or when a foreign object gets between the blade 54 and the pump chamber 43 (volute) of the casing 41 and presses the blade 54, the guide wall 107 can support the deformation of the blade 54 caused by the force applied from the front surface side to the back surface side to the blade 54, thereby improving the strength of the blade 54 and preventing the blade 54 from being damaged.

[0073] Furthermore, by making the height of the guide wall 107 smaller than half the height of the blades 54 and by making the guide wall 107 curved, it is possible to suppress an increase in the flow resistance of the water in the impeller 42 and ensure a diameter for passing foreign matter. When suppressing an increase in the flow resistance of the water in the impeller 42, for example, it is preferable that one end of the guide wall 107 is provided up to a position facing the second blade 62. In other words, it is preferable that the end of the guide wall 107 is located at a position where the water that has passed through the second blade 62 can be prevented from colliding with the end face of the guide wall 107.

[0074] In addition, since the second groove 105b is formed on the bottom surface of the first groove 105a, when the front and back surfaces of the tip of the blade 54 and the inner surface in the width direction of the first groove 105a are welded, the melted resin is filled into the second groove 105b. Therefore, the second groove 105b can prevent the melted resin material on the front and back surfaces of the blade 54 and the inner surface of the first groove 105a from overflowing from the first groove 105a to the blade 54 side and causing burrs on the blade 54. In addition, since the guide wall 107 abuts against the blade 54, the melted resin material at the portion where the guide wall 107 is provided is prevented from leaking by the guide wall 107, and the guide wall 107 also suppresses the generation of burrs. Therefore, it is possible to prevent a decrease in the performance of the impeller 42 due to the generation of burrs on the blade 54.

[0075] Furthermore, by configuring the front and back surfaces of the blades 54 to be welded to the welding grooves 105 of the front shroud 53, it is possible to increase the welding area compared to a configuration in which only the end faces of the blades 54 are welded, and therefore it is possible to improve the welding strength of the front shroud 53 and the blades 54. In particular, even in the impeller 42, which is a closed non-clog impeller with a small number of blades, the welding strength can be improved by increasing the welding area, and therefore sufficient strength for use can be obtained.

[0076] In addition, the impeller 42 has one or more holes 104 in the blades 54 and the same number of protrusions 106 as the holes 104 in the front shroud 53 for positioning the main plate 101 and the side plate 102, so that the main plate 101 and the side plate 102 can be easily aligned in the circumferential direction. Furthermore, the protrusions 106 are inserted into the holes 104, so that the main plate 101 and the side plate 102 can be prevented from being misaligned during welding, and the accuracy of the impeller 42 after welding can be improved. Furthermore, the protrusions 106 and the holes 104 are engaged in a direction perpendicular to the axis, so that in addition to improving the strength of the welded portion of the welded front shroud 53 and the blades 54, the strength can be improved by mechanical engagement of the holes 104 and the protrusions 106. Therefore, the holes 104 and the protrusions 106 can improve the strength of the impeller 42 assembled together by welding.

[0077] Furthermore, by providing at least some of the holes 104 in the thick portion 54a, sink marks in the thick portion 54a of the blade 54 can be suppressed during resin molding of the main plate 101 by injection molding or the like. Furthermore, by providing at least any of the holes 104 in the thick portion 54a, which has high strength, the protrusion 106 engages with the portion having high strength.

[0078] Furthermore, by providing the protrusion 106 with a plurality of ribs 106a, the ribs 106a melt when the front shroud 53 and the blades 54 are welded together. Then, the holes 104 and the protrusion 106 are welded together by the melted ribs 106a, so that the protrusion 106 can be firmly fixed to the holes 104.

[0079] In addition, since the impeller 42 is formed from a resin material, there is no risk of the impeller 42 corroding, and therefore there is no need to apply painting or the like to improve corrosion resistance, which was required when the impeller was formed from a metallic material such as grey cast iron. This makes it easier to manufacture the impeller 42, and the manufacturing costs of the impeller 42 can be reduced.

[0080] In addition, by using polyamide resin as the resin material, high wear resistance can be obtained. In particular, the closed non-clog impeller 42 is often used for pumping wastewater, and wear of the impeller 42 caused by impurities in the wastewater can be suppressed.

[0081] Moreover, polyamide resin has a relatively high rigidity among resin materials. Also, since it is a thermoplastic resin material, it can be molded by injection molding, and as in the above example, the impeller 42 can be assembled as a whole by integrally molding the rear shroud 52 and the blades 54 and welding the front shroud 53. In this way, the impeller 42 can be manufactured easily and has relatively high strength in the fields of buckling strength and compressive strength, so that deformation and damage caused by driving the submersible pump 1 can be prevented.

[0082] Furthermore, by making the impeller 42 from a polyamide resin having more than 6 carbon atoms in one unit, more specifically, a semi-aromatic polyamide resin, the impeller 42 has low water absorption. This makes it possible to prevent the impeller 42 from absorbing water. In particular, if the impeller 42 absorbs water, there is a risk of a decrease in strength due to hydrolysis and a change in dimensions due to water absorption, which can lead to breakage and a decrease in pump efficiency. In contrast, the impeller 42 of this embodiment uses a resin material with low water absorption, so that breakage and a decrease in pump efficiency can be prevented.

[0083] In addition, by using a resin material, the weight of the impeller 42 can be reduced compared to when it is molded from a metal material. In particular, when the impeller 42 is a non-clog impeller, if a single blade 54 is used, the impeller 42 has an asymmetric shape and the mechanical balance is shifted from the center of rotation. However, since the specific gravity of a resin material is smaller than that of a metal material, the influence of the mechanical balance during the rotation of the impeller can be reduced. Therefore, the impeller 42 does not require processing to obtain the mechanical balance, and the manufacturing process and manufacturing costs can be reduced. In addition, by improving the mechanical balance during the rotation of the impeller, the load applied to the bearing 25 due to the unbalance, for example, the radial load, is reduced, and the life of the bearing 25 can be improved.

[0084] As described above, by molding the impeller 42 from a resin material by injection molding, the quality can be improved in terms of surface roughness, corrosion resistance, and light weight compared to manufacturing an impeller by casting using gray cast iron or stainless steel cast steel, and the cost can be reduced because painting and balancing are not required. Furthermore, the procurement period, which would normally take about one month with casting, can be shortened to about one day.

[0085] Furthermore, when the impeller 42 is molded from a resin material, the rear shroud 52 and the blades 54 are integrally molded, so that the strength of the rear shroud 52 can be improved.

[0086] As described above, according to the impeller 42 and the submersible pump 1 using the impeller 42 according to one embodiment of the present invention, the welding strength between the blades 54 and the front shroud 53 can be improved.

[0087] The present invention is not limited to the above-described embodiment. For example, in the above-described example, the guide wall 107 is provided on the back surface of the end of the first blade 61 and the back surface of the end of the third blade 63, but the present invention is not limited to this. For example, the guide wall 107 may be provided in another location, or the guide wall 107 may be provided at a position facing the entire back surface of the blade 54. For example, the guide wall 107 may be provided on the front side as well as the back side of the blade 54. For example, the guide wall 107 may be provided intermittently on the end side of the first blade 61.

[0088] In the above example, the impeller 42 has three holes 104 formed in the blades 54 and three protrusions 106 provided on the front shroud 53, but the present invention is not limited to this. For example, the number of holes 104 and protrusions 106 may be one or more than three. Since the position of the blades 54 can be guided by the first groove 105a, the impeller 42 may not have the holes 104 and protrusions 106. However, the impeller 42 preferably has the holes 104 and protrusions 106 from the viewpoints of positioning, strength, and the like. The protrusions 106 have a plurality of ribs 106a, but the present invention is not limited to this, and the impeller 42 may not have the ribs 106a.

[0089] Further, the example of the impeller 42 in which the blade 54 has the first blade 61, the second blade 62, and the third blade 63 has been described, but the present invention is not limited to this. For example, the blade 54 may be formed of the first blade 61 and the second blade 62, or may be a single blade curved at a predetermined curvature. Furthermore, the thickness (width) of the blade 54 can be appropriately set depending on the strength, etc., and may be formed to have a uniform thickness, or may be set to a thickness that varies depending on the position.

[0090] That is, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made in the implementation stage without departing from the gist of the invention. In addition, the embodiments may be implemented in appropriate combination, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes various inventions, and various inventions can be extracted by combinations selected from the multiple components disclosed. For example, if the problem can be solved and the effect can be obtained even if some components are deleted from all the components shown in the embodiment, the configuration from which the components are deleted can be extracted as an invention. [Explanation of symbols]

[0091] 1...Submersible pump, 10...Motor, 11...Shaft seal device, 12...Pump, 13...Connecting pipe, 13a...Leg, 21...Motor casing, 22...Stator, 23...Rotor, 24...Rotating shaft, 25...Bearing, 26...Power cable, 30...Seal casing, 31...Mechanical seal, 33...Insertion hole, 34...Oil chamber, 41...Casing, 42...Impeller, 43...Pump chamber, 48...Leg, 49...Suction opening mouth, 50...discharge opening, 52...rear shroud, 52a...insertion hole, 53...front shroud, 54...blade, 54a...thick portion, 58...suction port, 59...discharge port, 61...first blade, 62...second blade, 63...third blade, 64...connecting wall, 101...main plate, 102...side plate, 104...hole, 105...welding groove, 105a...first groove, 105b...second groove, 106...projection portion, 106a...rib, 107...guide wall.

Claims

1. A motor; A pump casing; a rotating shaft having one end connected to the motor and the other end disposed within the pump casing; an impeller comprising: a rear shroud formed of a resin material and fixed to the rotating shaft; a main plate having blades integrally molded with the rear shroud; a front shroud having a suction port; a side plate provided on a rear surface of the front shroud, into which tips of the blades are inserted, the side plate having a welding groove recessed in the shape of the tip of the blade, the side plate being disposed adjacent to at least a portion of the welding groove in a width direction of the welding groove and having an outer surface along the blade on the welding groove side; and Equipped with The vanes extend along an axial direction, an outer surface of the guide wall on the welding groove side extends along the axial direction and is formed in the same shape as an opposing outer surface of the blade; The width of the guide wall gradually narrows from the back surface side of the front shroud toward the tip.

2. An underwater pump as described in claim 1, wherein the outer surface of the guide wall on the welding groove side and the outer surface opposite in the width direction are formed curvedly.

3. The blade has a first blade and a second blade, the first blade is disposed on a peripheral edge of the suction port from one end toward a center side, and extends from the center side to the other end away from the suction port to an outer peripheral edge of the rear shroud and the front shroud; the second blade is disposed between the suction port and the first blade, facing an inner peripheral surface of the first blade at a predetermined distance, one end of the second blade is disposed on a peripheral edge of the suction port, and a center side of the second blade extends away from the suction port toward an outer peripheral edge side of the rear shroud and the front shroud, 3. The underwater pump according to claim 1, wherein the guide wall is provided at least opposite an end of the blade on the outer peripheral edge side of the rear shroud, and is provided at an end of the welding groove on the back side of the first blade and on the outer peripheral edge side of the front shroud.

4. The blade further includes a third blade, the third blade is provided at a symmetrical position to the first blade around the axis of the rear shroud and the axis of the front shroud, The submersible pump according to claim 3 , wherein the other of the guide walls is provided at an end of the welding groove that is on the back side of the third blade and on the main surface side of the front shroud.

5. 5. An underwater pump as claimed in any one of claims 1 to 4, wherein the welding groove comprises a first groove having a width equal to or greater than the thickness of the blade, and a second groove formed on the bottom surface of the first groove and having a width smaller than the width of the first groove and the thickness of the blade.

6. the vane has at least one hole formed in an end opposite the front shroud; the side plate has positioning projections, the number of which is equal to the number of the holes, provided inside the welding groove and at positions facing the holes; The blade has a thick portion having a partially thicker thickness, The submersible pump according to claim 1 , wherein the hole is provided in the thick portion.

7. The blade has a first blade and a second blade, The end of the second blade on the suction port side and the end of the first blade are integrated to form a thick portion, The submersible pump according to claim 6 , wherein the hole is formed in an end surface of the thick-walled portion.

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