JP2023004057A - impeller and submersible pump - Google Patents

Abstract

To provide an impeller and a submersible pump capable of increasing welded surfaces 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, and 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, 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 6

Description

TECHNICAL FIELD The present invention relates to an impeller and a submersible pump for conveying sewage or the like.

A centrifugal pump in which an impeller is accommodated in a spiral casing is used as a submersible pump for conveying sewage or the like. Such a submersible pump, for example, sucks sewage from a suction port provided on the bottom surface of the casing and discharges it from a discharge port provided on the side surface of the casing by rotating the impeller.

Submersible pumps used for conveying such sewage reliably discharge sewage contained in sewage in order to prevent failures due to foreign substances contained in sewage being caught in rotating shafts, impellers, etc. configuration is required.

For this reason, for example, a so-called semi-open impeller in which a plurality of blades are provided on one shroud is used as the impeller. However, such impellers have poor pumping efficiency, so closed impellers are known that are used when high efficiency is required.

Such a closed impeller has a configuration in which blades are provided between two shrouds, and there is a high possibility that foreign matter may be caught in the impeller compared to a semi-open impeller.

For this reason, an impeller provided with one blade between the shrouds is known as a closed non-clog impeller (see, for example, Patent Document 1). Such impellers are then manufactured in gray cast iron or stainless cast steel by casting.

However, since the impeller described above is manufactured by casting, it has a rough surface, which may reduce pump efficiency. In addition, impellers made of gray cast iron require painting to prevent rust, which increases manufacturing costs.

Impellers made from cast stainless steel can be a procurement problem due to the time required to manufacture them. Moreover, since such an impeller is made of a material having a large specific gravity, there is also the problem that it is necessary to maintain a mechanical balance during rotation of the impeller.

Therefore, it is conceivable to mold the closed non-clog impeller with a resin material. For example, as a method of manufacturing an impeller with a resin material, there is also known a technique of separately molding a front shroud and a back shroud having a plurality of blades (see, for example, Patent Document 2).

JP 2012-77671 A Japanese Patent No. 6006987

In the impeller of Patent Document 2 described above, different ultrasonic welding is required for the welding rib provided at the center of the blade and the crimping rib. Further, the impeller of Patent Document 2 has a welded rib at the center of each blade, and has a structure in which a plurality of blades are provided at regular intervals, so that sufficient welding strength can be ensured.

However, the closed non-clog impeller has only one blade, or at most two blades, which is a small number of blades. If the number of blades is small, the surface to be welded with the shroud is small, and the strength of the welded impeller may be insufficient.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an impeller and a submersible pump that can increase the welding area between the blades and the shroud.

According to one aspect of the present invention, the impeller is formed of a resin material and includes a back shroud fixed to a rotating shaft, blades provided on the back shroud, a front shroud having a suction port, and The front and back surfaces of the blade are welded to the front shroud in a state in which the blade is placed in the welding groove. and a side plate.

According to one aspect of the present invention, a submersible pump is formed of a motor, a pump casing, a rotary shaft having one end connected to the motor and the other end arranged in the pump casing, and a resin material, and A rear shroud fixed to a rotating shaft, blades provided on the rear shroud, a front shroud having an intake port, and a tip shape of the blades provided on the rear surface of the front shroud and into which the blade tips are inserted. and an impeller having a side plate with recessed welding grooves, wherein the front and back surfaces of the blades are welded to the front shroud in a state in which the blades are arranged in the welding grooves.

ADVANTAGE OF THE INVENTION According to this invention, the impeller and submersible pump which can increase the welding area of a blade|wing and a shroud can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a partial cross-section of the configuration of a submersible pump according to an embodiment of the present invention; Sectional drawing which shows the structure of the impeller of the same submersible pump. The perspective view which shows the structure of the main plate of the same impeller. The perspective view which shows the structure of the side plate of the same impeller. The perspective view which shows the structure of the protrusion part provided in the same side board. Explanatory drawing which shows an example of manufacture of an impeller while showing the principal part structure of the same impeller.

A submersible pump 1 and an impeller 42 according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 6. FIG.
FIG. 1 is an explanatory diagram showing a partial cross-section of the configuration of a submersible pump 1 according to an embodiment of the present invention, and FIG. 2 shows the configuration of an impeller 42 of the submersible pump 1 in a cross-section taken along line II-II in FIG. 3 is a perspective view showing the configuration of the main plate 101 of the impeller 42, FIG. 4 is a perspective view showing the configuration of the side plate 102 of the impeller 42, and FIG. FIG. 6 is a perspective view showing the configuration of the end portions of the blades 54 of the impeller 42 and the welding grooves 105 of the front shroud 53 used in the submersible pump 1, and is an explanatory diagram showing an example of manufacturing the impeller 42. As shown in FIG.

As shown in FIG. 1, the submersible pump 1 includes a motor 10, a shaft seal device 11, a pump 12, and a connecting pipe 13. Such a submersible pump 1 is installed in a sewage tank, a sewage system, or the like, and is a so-called submersible sewage pump that feeds sewage containing foreign matter (filth, etc.).

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 rotary 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 bolts or the like.

The stator 22 is fixed to the inner surface of the motor casing 21 . The stator 22 is formed to rotate the rotor 23 with electric power supplied through the power cable 26 . The rotor 23 is fixed to the rotating shaft 24 so that the rotating shaft 24 can rotate following its rotation.

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 such as a bearing. The rotary shaft 24 extends from the motor casing 21 in the direction of gravity when the submersible pump 1 is installed on the installation surface.

The shaft sealing device 11 has a seal casing 30 and a mechanical seal 31 . The shaft sealing device 11 liquid-tightly partitions the motor 10 , the pump 12 and the rotating shaft 24 .

The seal casing 30 is formed to accommodate a 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 in both end faces. Further, the seal casing 30 forms therein an oil chamber 34 that can be filled with lubricating oil for the mechanical seal 31 . For example, the seal casing 30 is composed of two axially divided component parts, which are integrally assembled to form an oil chamber 34 therein.

The mechanical seal 31 seals between the seal casing 30 and the rotating shaft 24 to prevent infiltration of dirty water from the pump 12 and infiltration of lubricating oil into the motor 10 .

The pump 12 has a casing 41 and an impeller 42 . The casing 41 is a spiral casing that accommodates the impeller 42 therein and forms a pump chamber 43 therein. The casing 41 is composed of a plurality of component parts, and is assembled to form a pump chamber 43 therein.

The casing 41 has a plurality of legs 48 for mounting the submersible pump 1 on the mounting surface. The casing 41 also includes a suction opening 49 provided on the bottom surface and between the plurality of legs 48, and a discharge opening 50 provided on a portion of the side surface.

The suction opening 49 is formed to have substantially the same diameter as the suction port 58 of the impeller 42, which will be described later. The suction opening 49 may have a liner ring that rotatably supports the impeller 42 .

The discharge opening 50 is formed so that a diameter (discharge diameter) thereof can pass foreign matter having a particle size that can pass through the impeller 42 . Specifically, the diameter of the discharge opening 50 is formed to have substantially the same diameter as the foreign matter of a predetermined particle diameter that can pass through the impeller 42 . Here, the foreign matter having a predetermined particle size that can pass through the impeller 42 is, for example, a spherical solid having the same diameter (predetermined particle size) as the diameter (discharge diameter) of the discharge opening 50 of the submersible pump 1 .

As shown in FIGS. 1 to 4, the impeller 42 is a closed non-clog impeller, and is formed so as to be able to pass foreign matter of a predetermined particle size. Such an impeller 42 includes a back shroud 52 arranged on the shaft sealing device 11 side, a front shroud 53 arranged opposite to the back shroud 52 and arranged on the suction opening 49 side, and between these shrouds 52 and 53. and a vane 54 provided in the.

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

The resin material forming the impeller 42 is, for example, polyamide resin. The polyamide resin is preferably a low water absorbing polyamide resin having more than 6 carbon atoms per unit. Also, the polyamide resin is preferably a semi-aromatic polyamide resin.

The back shroud 52 is formed in a disc shape. The back shroud 52 is formed with an insertion hole 52a having a key groove in the center thereof, into which the rotating shaft 24 can be inserted. The insertion hole 52a is formed with a key groove for the purpose of firmly fixing the rotating shaft 24 and improving the strength, and an insert member capable of fixing the rotating shaft 24 is inserted into the back shroud 52. may be formed of The rear shroud 52 is positioned above the front shroud 53 with respect to the direction of gravity when the impeller 42 is fixed to the rotating shaft 24 .

The front shroud 53 is formed in an annular shape. A suction port 58 is formed in the center of the front shroud 53 . The suction port 58 , for example, protrudes in a cylindrical shape from the surface side of the front shroud 53 .

The vane 54 is provided integrally between the rear shroud 52 and the front shroud 53 . As shown in FIGS. 2 and 3, the blade 54 includes a first blade 61, a second blade 62, and a third blade 63. As shown in FIGS. Further, the blade 54 forms a connection wall 64 that connects one end of the first blade 61, the end of the second blade 62 on the side of the suction port 58, and the end of the third blade 63 on the side of the suction port 58.

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 of the shrouds 52 and 53 toward the outer peripheral edge. Also, for example, the first blade 61, the second blade 62 and the third blade 63 are formed to have the same thickness.

One end (connecting wall 64) side of the first blade 61 is located on the center side of the shrouds 52 and 53 and on the periphery of the suction port 58 of the front shroud 53, and the other end is located on the shroud 52. , 53. More specifically, the first blade 61 is arranged along the periphery of the suction port 58 from one end toward the center, and is spaced apart from the suction port 58 from the center to the other end. and extends to the outer perimeter of the shrouds 52,53. The first blade 61 is integrally formed with the second blade 62 and the third blade 63 by a connecting wall 64 formed by one end.

One end of the second blade 62 on the suction port 58 side is formed integrally 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 from the first blade 61 and extends from the suction port 58 toward the outer peripheral side of the shrouds 52 and 53 . Further, the second blade 62 is separated from the outer peripheral edges of the shrouds 52 and 53 at the ends on the outer peripheral edge side of the shrouds 52 and 53 . As a specific example, the second blade 62 is provided by branching from the inner peripheral surface of the connecting wall 64 , in other words, from the inner peripheral surface of the first blade 61 on the central side of one end side. The second blade 62 has an end on the side of the first blade 61 arranged at the periphery of the suction port 58 , and the other end from the center side is separated from the suction port 58 and curved with a predetermined radius of curvature. The second blade 62 is arranged to face a part of the first blade 61 and the inner peripheral surface of the first blade 61 with a predetermined distance therebetween. It is arranged apart from one blade 61 . The second blade 62 is provided facing the first blade 61 so that the internal flow path in the impeller 42 from the suction port 58 changes constantly.

The third blade 63 is formed asymmetrically with each of the first blade 61 and the second blade 62 . The third blade 63 is provided by branching 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 edges of the shrouds 52 and 53 , and the ends of the shrouds 52 and 53 on the outer peripheral edges are separated from the outer peripheral edges of the shrouds 52 and 53 . The third blade 63 is provided at a symmetrical position around the axis of the first blade 61 and the shrouds 52 and 53 . Here, symmetrical positions include substantially symmetrical positions.

The connecting wall 64 is provided between the back shroud 52 and the front shroud 53 and radially opposed to the third blade 63, and is configured by the end portion side of the first blade 61 on the suction port 58 side. . The connection wall 64 connects the first blade 61 , the end of the second blade 62 on the side of the suction port 58 , and the end of the third blade 63 on the side of the suction port 58 along the edge of the suction port 58 . That is, 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 side of the suction port 58 toward the outer peripheral edges of the shrouds 52 and 53. Form.

In the impeller 42 configured in this manner, the ends of the third blades 63 on the suction port 58 side and the ends of the second blades 62 on the suction port 58 side are connected to the ends of the first blades 61 (connection wall 64). ) are integrally formed. With this configuration, the impeller 42 forms a flow path from the suction port 58 toward the discharge port 59 through the inner peripheral surface of the first blade 61 (connecting wall 64 ) and the end portion of the third blade 63 . While forming, water is pumped by 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 constitutes a so-called 1.5-blade non-clog impeller with the first blades 61 and the third blades 63 . In addition, the second blades 62 of the impeller 42 keep the amount of change in the cross-sectional area of the flow path from the suction port 58 to the discharge port 59 approximately constant, thereby suppressing excessive changes in the cross-sectional area of the flow path.

Also, the ends of the first blade 61 (connecting wall 64) and the third blade 63 on the side of the suction port 58, and the first blade 61 (connecting wall 64) on the side of the suction port 58 and the second blade on the side of the suction port 58 The thickness of the portion where the end portion of 62 is integrally formed is formed to be thicker than the thicknesses of the first blade 61 , the second blade 62 and the third blade 63 . That is, the blade 54 partially has a thick portion 54a. In this embodiment, the blades 54 are configured to be thicker than the other portions at two continuous portions of the first blade 61 and the third blade 63, and the first blade 61 and the second blade 62. It has a thick portion 54a.

As a specific example, such an impeller 42 includes a main plate 101 in which a back shroud 52 and blades 54 are integrally formed of a resin material by injection molding, and a front shroud 53, as shown in FIGS. is formed by welding together with the side plate 102 molded of a resin material by injection molding.

As shown in FIG. 3 , the main plate 101 is shaped to have a rear shroud 52 , vanes 54 , and at least one hole 104 formed at the end of the vanes 54 facing the front shroud 53 .

The hole 104 is set to a predetermined depth from the end face of the vane 54 . The holes 104 are used for circumferential alignment of the main plate 101 and the side plates 102 . For example, multiple holes 104 are provided. At least some of the plurality of holes 104 are provided in the end surface of the thick portion 54 a of the blade 54 . In this embodiment, the blade 54 has two thick portions 54a. Further, in this embodiment, the plurality of holes 104 are provided at three locations on the end surface of the blade 54 .

Therefore, in the example of this embodiment, two of the three holes 104 are arranged in the thick portion 54 a of the blade 54 . To explain a specific example, the two holes 104 are the ends of the first blade 61 and the third blade 63 on the suction port 58 side, and the ends of the second blade 62 on the suction port 58 side. It is formed on the end faces of two thick portions 54a integrally formed on the end side (connecting wall 64). In addition, the remaining one hole 104 is provided at a position that is equidistant from the other two holes 104 as much as possible. It is provided on the end face on the side end portion side.

As shown in FIG. 4 , the side plate 102 includes the front shroud 53 , welding grooves 105 formed on the back surface of the front shroud 53 facing the back shroud 52 , and protrusions provided in the welding grooves 105 and having the same number of protrusions as the holes 104 . 106 and .

The welding groove 105 is formed in a shape that allows the end of the blade 54 to be inserted thereinto. That is, the width of the welding groove 105 on the back 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 arranged. In other words, the welding groove 105 is formed on the back side of the front shroud 53 in the same shape as the end face of the blade 54 or in a shape 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 formed on the bottom surface of the first groove 105a and narrower than the first groove 105a.

Here, the width of the blade 54 and the width of the welding groove 105 (the first groove 105a and the second groove 105b) are the directions perpendicular to the extending direction of the blade 54 and the welding groove 105, and the width of the front surface and the rear surface of the blade 54. It is the opposite direction. Here, the back surface of the blade 54 is 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 is the main surface on the outer side in the radial direction. In other words, the back surface of the blades 54 is the primary side surface in the rotational direction of the impeller 42 , and the front surface of the blades 54 is the secondary side surface in the rotational direction of the impeller 42 . Therefore, the surface of the blades 54 is the surface that presses the water of the blades 54 when the impeller 42 rotates.
As a preferred example, as shown in FIG. 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, T2> A relationship of T1>T3 is set. That is, considering the insertion (fitting) of the vane 54 into the welding groove 105, dimensional accuracy, etc., it is preferable that the width T2 of the first groove 105a is set larger than the width T1 of the vane 54. FIG.

The dimensional difference (gap) between the width T1 of the blades 54 and the width T2 of the first grooves 105a is such that the blades 54 can be aligned with the welding grooves 105, and the resulting gaps reduce the performance of the impeller 42. Not set to dimensional difference. 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 can prevent foreign matter and dirt contained in the sewage from being caught. The dimensional difference is appropriately set depending on the accuracy of the molding technique (injection molding), the environment in which the submersible pump 1 (impeller 42) is used, the required performance, and the like. Here, the setting according to the environment in which the submersible pump 1 is used means that, in the case of a sewage pump that pumps up water containing foreign matter and filth, foreign matter and filth are caught in the gap between the blade 54 and the first groove 105a. and setting a dimensional difference that can suppress deposition and the like.

The first groove 105 a is formed in the shape of the axial end face of the blade 54 . The first groove 105a enables alignment of the blade 54 by inserting the end of the blade 54 . Therefore, the width of the first groove 105a is set to be the same width as the blade 54 or slightly larger than the blade 54 .

When the blades 54 inserted in the first groove 105a and the side plate 102 (front shroud 53) are welded together, part of the melted blades 54 and the side plate 102 (front shroud 53) of the main plate 101 flows into the second groove 105b. Configure the space for penetration. The width of the second groove 105 b is set to be smaller than the width of the blade 54 .

The protrusion 106 is provided within the welding groove 105 . The plurality of projections 106 are provided at positions where they can be inserted into the plurality of holes 104 provided in the blade 54 when the blade 54 is arranged in the welding groove 105 of the welding groove 105 . As a specific example, the protrusion 106 is provided on the bottom surface of the second groove 105b. In addition, when the width of the second groove 105b is smaller than the outer diameter of the protrusion 106, the protrusion 106 is provided over the first groove 105a and the second groove 105b.

The protruding portion 106 is formed in a cylindrical shape with a diameter equal to or slightly smaller than the inner diameter of the hole 104 . Also, the projection 106 has a tip with a small diameter to guide insertion into the hole 104 . As a specific example, as shown in FIG. 5, the protruding portion 106 is formed in a cylindrical shape with a semicircular tip. Further, as shown in FIG. 5, the protrusion 106 has ribs 106a at a plurality of locations on the outer peripheral surface, for example, at four locations in the circumferential direction. The rib 106 a is formed in a triangular plate shape provided at the corner between the bottom surface of the second groove 105 b and the outer peripheral surface of the projection 106 .

The connecting pipe 13 is connected to the discharge opening 50 . The connecting pipe 13 is, for example, a vent pipe that is bent upward at 90 degrees from the discharge opening 50 . The connecting pipe 13 has, for example, legs 13a.

Next, a method of manufacturing the impeller 42 configured in this manner will be described with reference to FIG.
First, as in step ST1 shown in FIG. 6, the main plate 101 integrally formed with the rear shroud 52 and the blades 54 and the side plate 102, which is the front shroud 53, are molded by injection molding. Then, the blades 54 are arranged to face the welding grooves 105 formed in the front shroud 53 .

Then, as in step ST2 shown in FIG. 6, the blades 54 of the main plate 101 are arranged in the first grooves 105a of the side plate 102 . At this time, the blades 54 are inserted (fitted) into the first grooves 105a with the front and back surfaces of the blades 54 aligned with the first grooves 105a.

Next, as in step ST3 shown in FIG. 6, the vane 54 is 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 tips of the blades 54 and both sides in the width direction of the first groove 105a are welded. At this time, as shown in FIG. 6, the inner side surface and the bottom surface of the first groove 105a and the front and back surfaces and the end surface of the blade 54 are melted.

In addition, as shown in FIG. 6, for example, the penetration amount in the axial direction is set to a range shallower than the depth of the first groove 105a. The impeller 42 is formed by these steps.

In the impeller 42, an example in which the rear shroud 52 and the blades 54 are integrally formed by injection molding has been described, but for example, the rear shroud 52 and the blades 54 may be formed separately 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 blades 54 may be welded together. In addition, the impeller 42 may have holes 104 at the ends of the blades 54 facing the back shroud 52 , and protrusions 106 on the bottom surface of the second grooves 105 b of the back shroud 52 . Alternatively, the front shroud 53 and the blades 54 may be integrally formed by injection molding. However, from the viewpoint of the shape of the impeller 42 and the reduction of the manufacturing process, it is preferable to weld the two components of the main plate 101 and the side plate 102 to form the integral impeller 42 as described above.

According to the impeller 42 and the submersible pump 1 configured as described above, since the impeller 42 is formed of a resin material, the surface roughness of the impeller 42 can be reduced compared to an impeller formed of a metal material. can be smoothed out. Therefore, when the submersible pump 1 is driven, water resistance and friction can be reduced, and pump efficiency can be improved.

In addition, the impeller 42 can be easily manufactured because the main plate 101 and the side plates 102 are integrally formed by welding. In addition, the impeller 42 is provided with a welding groove 105 having a first groove 105a and a second groove 105b on one main surface (rear surface) of the front shroud 53 of the side plate 102, into which the tip of the blade 54 is inserted. It is molded integrally by welding the one groove 105a. Further, the front shroud 53 and the blades 54 are fixed by welding the front and back surfaces of the blades 54 and the inner side surfaces of the first grooves 105a.

At this time, 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 of the first groove 105a in the width direction are welded, the melted resin is The second groove 105b is filled. Therefore, the second grooves 105b can prevent the melted resin material on the front and back surfaces of the blades 54 and the inner surfaces of the first grooves 105a from overflowing from the first grooves 105a toward the blades 54 and causing burrs on the blades 54. Therefore, it is possible to prevent deterioration of the performance of the impeller 42 due to burrs on the blades 54 .

In addition, by adopting a configuration in which the front and back surfaces of the blades 54 are welded to the welding grooves 105 of the front shroud 53, the welding area can be improved compared to a configuration in which only the end surfaces of the blades 54 are welded. It is possible to improve the welding strength of the front shroud 53 and the blades 54 . In particular, even with 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, so that sufficient strength for use can be obtained.

Further, 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 plates 102. Circumferential alignment of 102 is facilitated. Further, by inserting the protrusion 106 into the hole 104, it is possible to prevent the main plate 101 and the side plate 102 from slipping during welding, so that the accuracy of the impeller 42 after welding can be improved. Further, since the protrusion 106 and the hole 104 are engaged in the direction orthogonal to the axis, the strength of the welded portion of the front shroud 53 and the blades 54 is improved, and the hole 104 and the protrusion 106 are mechanically engaged. It is possible to improve the strength by combining. Therefore, the hole 104 and the protrusion 106 can improve the strength of the impeller 42 integrally assembled by welding.

Further, by providing at least some of the plurality of holes 104 in the thick portion 54a, sink marks in the thick portion 54a of the blade 54 can be suppressed in resin molding of the main plate 101 by injection molding or the like. Moreover, by providing at least one of the holes 104 in the thick portion 54a having high strength, the projecting portion 106 is engaged with the portion having high strength.

Further, by providing a plurality of ribs 106a on the projecting portion 106, the ribs 106a are melted when the front shroud 53 and the blades 54 are welded. Since the hole 104 and the protrusion 106 are welded by the melted rib 106a, the protrusion 106 can be firmly fixed to the hole 104. FIG.

In addition, since the impeller 42 is made of a resin material, there is no possibility of the impeller 42 corroding. etc. is not necessary. Therefore, the impeller 42 can be manufactured easily, and the manufacturing cost of the impeller 42 can be reduced.

Moreover, high wear resistance can be obtained by using a polyamide resin as the resin material. In particular, the closed non-clog impeller 42 is often used for pumping sewage, and can suppress wear of the impeller 42 due to impurities in the sewage.

Polyamide resin has relatively high rigidity among resin materials. Also, since it is a thermoplastic resin material, it can be molded by injection molding. It is possible to assemble to In this manner, the manufacturing method is easy, and the impeller 42 having relatively high strength such as buckling strength and compressive strength can be obtained. .

In addition, by making the impeller 42 from a polyamide resin having more than 6 carbon atoms in one unit, more specifically from a semi-aromatic polyamide resin, it has low water absorbency. Thereby, it is possible to suppress the water absorption of the impeller 42 . In particular, when the impeller 42 absorbs water, there is a risk that strength will be reduced due to hydrolysis, and dimensional changes will occur due to water absorption. On the other hand, the impeller 42 of the present embodiment uses a resin material with low water absorption, so it is possible to suppress damage and deterioration of pump efficiency.

Further, by using a resin material for the impeller 42, the weight can be made smaller than when the impeller is made of a metal material. In particular, since the impeller 42 is a non-clog impeller, if it is configured to use one blade 54, it will have an asymmetrical shape, and the mechanical balance will be shifted from the center of rotation. However, since the resin material has a smaller specific gravity than the metal material, it can reduce the influence of the mechanical balance when the impeller rotates. For this reason, the impeller 42 does not require machining for obtaining mechanical balance, so the manufacturing process and manufacturing cost can be reduced. Further, by improving the mechanical balance during rotation of the impeller, the load applied to the bearing 25 due to the imbalance, for example, the radial load, is reduced, so that the service life of the bearing 25 can be extended.

As described above, by molding the impeller 42 with a resin material by injection molding, surface roughness, corrosion resistance, and lightness are improved in terms of quality compared to manufacturing the impeller by casting using gray cast iron or stainless cast steel. The cost can be reduced because painting and balance processing are not required, and the procurement period, which used to take about one month for casting, can be shortened to about one day.

Further, by integrally molding the back shroud 52 and the blades 54 when the impeller 42 is molded from a resin material, the strength of the back shroud 52 can be improved.

As described above, according to the impeller 42 and the submersible pump 1 using the impeller 42 according to the embodiment of the present invention, the welded area between the blades 54 and the front shroud 53 can be increased.

In addition, this invention is not limited to embodiment mentioned above. For example, in the above example, an example of the impeller 42 having three holes 104 formed in the blades 54 and three projections 106 provided in the front shroud 53 was described, but the present invention is not limited to this. For example, the number of holes 104 and projections 106 may be singular or plural other than three. Further, since the position of the blade 54 can be guided by the first groove 105a, a configuration without the hole 104 and the protrusion 106 may be employed. However, impeller 42 preferably has holes 104 and protrusions 106 from the viewpoint of positioning and strength. Moreover, although the projecting portion 106 is configured to have a plurality of ribs 106a, it is not limited to this, and may be configured to have no ribs 106a.

Moreover, although the example of the impeller 42 in which the blades 54 have the first blades 61, the second blades 62 and the third blades 63 has been described, the present invention is not limited to this. For example, the blade 54 may be formed by a first blade 61 and a second blade 62, or may be a single blade curved with a predetermined curvature. Further, the thickness (width) of the blades 54 can be appropriately set according to the strength and the like, and the thickness may be uniform, or may be set to differ depending on the position.

That is, the present invention is not limited to the above-described embodiments, and can be variously modified in the implementation stage without departing from the scope of the invention. Further, each embodiment may be implemented in combination as appropriate, in which case the combined effect can be obtained. Furthermore, various inventions are included in the above embodiments, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, if the problem can be solved and effects can be obtained, the configuration with the constituent elements deleted can be extracted as an invention.

Reference Signs List 1 Submersible pump 10 Motor 11 Shaft sealing 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 , 50... Discharge opening 52... Back shroud 52a... Insertion hole 53... Front shroud 54... Blade 54a... Thick portion 58... Suction port 59... Discharge port 61... First blade 62... Third 2 blades 63 third blade 64 connecting wall 101 main plate 102 side plate 104 hole 105 welding groove 105a first groove 105b second groove 106 protrusion 106a rib.

Claims (12)

a back shroud made of a resin material and fixed to the rotating shaft;
a vane provided on the back shroud;
A front shroud having a suction port and a welding groove provided on the back surface of the front shroud and recessed into the tip shape of the blade into which the tip of the blade is inserted, with the blade being arranged in the welding groove , a side plate in which the front and back surfaces of the blades are welded to the front shroud;
impeller with The welding groove is formed in a first groove having a width equal to or larger than the thickness of the blade and a bottom surface of the first groove, and the width of the first groove and the width of the blade 2. The impeller of claim 1, having a second groove of width less than thickness. said vane having at least one hole formed in an end opposite said front shroud;
3. The impeller according to claim 1, wherein the side plate has the same number of positioning projections as the holes provided inside the welding grooves and at positions facing the holes. 4. The impeller according to claim 3, wherein said side plate has a plurality of welded ribs formed at corners of said protrusion and said front shroud. The blade has a thick portion with a partially thick thickness,
5. The impeller according to claim 3, wherein said hole is provided in said thick portion. The holes are provided at a plurality of locations at intervals in the circumferential direction,
6. The impeller of claim 5, wherein at least one of said holes is provided in said thickened portion. a motor;
a pump casing;
a rotary shaft having one end connected to the motor and the other end disposed within the pump casing;
A back shroud made of a resin material and fixed to the rotating shaft, blades provided on the back shroud, a front shroud having a suction port, and a front shroud provided on the rear surface of the front shroud, into which tips of the blades are inserted. an impeller having a side plate having a welding groove recessed in the tip shape of the blade, wherein the front and back surfaces of the blade are welded to the front shroud in a state in which the blade is arranged in the welding groove;
submersible pump. The welding groove is formed in a first groove having a width equal to or larger than the thickness of the blade and a bottom surface of the first groove, and the width of the first groove and the width of the blade 8. A submersible pump as claimed in claim 7, having a second groove with a width less than the thickness. said vane having at least one hole formed in an end opposite said front shroud;
9. The submersible pump according to claim 7, wherein the side plate has the same number of positioning protrusions as the holes provided inside the welding groove and at positions facing the holes. . 10. The submersible pump according to claim 9, wherein said side plate has a plurality of welded ribs formed at corners of said protrusion and said front shroud. The blade has a thick portion with a partially thick thickness,
11. The submersible pump according to claim 9, wherein said hole is provided in said thick portion. The holes are provided at a plurality of locations at intervals in the circumferential direction,
12. The submersible pump according to claim 11, wherein at least one of said holes is provided in said thickened portion.

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