Motor pump

Abstract

The present invention relates to a motor pump. The motor pump (MP) comprises a first impeller (1A) and a second impeller (1B) connected to a communication shaft (270). A boss section (281) of the first impeller (1A) is greater in size than a boss section (282) of the second impeller (1B).

Description

motor pump

[0001] The present invention relates to a motor pump.

[0002] BACKGROUND ART Pump devices are known that include a motor and a pump connected by a coupling. Such pump devices have a structure in which the driving force of the motor is transmitted to the impeller of the pump via the coupling.

[0003] Japanese Patent Application Laid-Open No. 2000-303986

[0004] However, in such pump devices, the pump and motor are arranged side by side, which results in a large installation area. On the other hand, in recent years, there has been an increasing demand for compactness (and energy saving), and as a result, there has also been an increasing demand for an integrated pump and motor structure.

[0005] Pumps and motors are mechanical devices that play an important role in lifelines, and therefore it is necessary not only to make pumps and motors more compact, but also to ensure stable operation of the pumps and motors.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a motor pump that has a compact structure and operates stably.

[0007] In one aspect, there is provided a motor pump including a first impeller, a rotor fixed to the first impeller, a stator disposed radially outward of the rotor, a first bearing supporting the first impeller and disposed outside a flow path of the first impeller, a communication shaft connected to the first impeller, and a second impeller connected to the communication shaft, wherein a boss portion of the first impeller is larger in size than a boss portion of the second impeller.

[0008] In one aspect, the motor pump includes a sleeve that forms a predetermined distance between the first impeller and the second impeller, and the sleeve is disposed between the first impeller and the second impeller. In one aspect, the motor pump includes a collet that fastens each of the first impeller and the second impeller to the communication shaft.

[0009] In one aspect, a motor pump is provided, comprising: a first impeller; a rotor fixed to the first impeller; a stator arranged radially outward from the rotor; a first bearing supporting the first impeller and arranged outside a flow path of the first impeller; a communication shaft connected to the first impeller; a second impeller connected to the communication shaft; and a second bearing arranged downstream of the second impeller and supporting the communication shaft.

[0010] In one aspect, the motor pump includes a discharge casing arranged downstream of the second impeller, and the second bearing includes a rotating-side bearing body arranged on the communicating shaft side and a fixed-side bearing body arranged on the discharge casing side. In one aspect, the rotating-side bearing body is a rotating-side cylindrical body attached to the communicating shaft, and the fixed-side bearing body is a fixed-side cylindrical body attached to the discharge casing and surrounding the rotating-side cylindrical body. In one aspect, the rotating-side bearing body is formed integrally with the communicating shaft, and the fixed-side bearing body is formed integrally with the discharge casing.

[0011] In one aspect, the motor pump includes a rotor holder that holds the rotor, and the first impeller is a press-molded product to which the rotor holder is fixed. In one aspect, the rotor holder includes a press-molded annular housing portion that houses the rotor, and an annular closing plate that closes the housing portion. In one aspect, the motor pump includes a rotor holder that holds the rotor, and the first impeller is a resin-molded product to which the rotor holder is integrally molded.

[0012] In one aspect, the rotor holder includes a resin-molded annular housing portion that houses the rotor, and a ring holder that closes the housing portion. In one aspect, the ring holder has a rotation prevention structure formed at a connection portion with the housing portion. In one aspect, the rotation prevention structure is an embedding hole in which a portion of the housing portion is embedded.

[0013] In one aspect, the anti-rotation structure is a bent portion that is bent in a U-shape. In one aspect, the first bearing includes a rotating-side bearing body attached to the rotor holder and a fixed-side bearing body arranged on the suction side of the rotating-side bearing body. In one aspect, the motor pump includes a stator casing that houses the stator and is resin-molded integrally with the stator.

[0014] In one aspect, the motor pump includes a motor frame that covers an outer peripheral surface of the stator casing and is in contact with the stator. In one aspect, the rotor and the first bearing are disposed in a suction side region of the impeller.

[0015] The motor pump includes a stator disposed radially outward of a rotor fixed to the first impeller, and the boss portion of the first impeller is larger in size than the boss portion of the second impeller. Therefore, the motor pump has a compact and strong structure. As a result, the motor pump can operate stably.

[0016] FIG. 4A is a diagram showing an embodiment of a motor pump. FIG. 4B is a diagram showing the flow of a treated liquid passing through a gap between a rotating-side bearing body and a fixed-side bearing body. FIG. 4C is a diagram showing an embodiment of a plurality of grooves formed in a flange portion of the fixed-side bearing body. FIG. 4A is a diagram showing an embodiment of a plurality of grooves formed in a cylindrical portion of the fixed-side bearing body. FIG. 4B is a diagram showing another embodiment of grooves formed in a cylindrical portion of the fixed-side bearing body. FIG. 4C is a diagram showing another embodiment of grooves formed in a cylindrical portion of the fixed-side bearing body. FIG. 5A is a diagram showing an embodiment of a thrust load reduction structure provided on the back surface of an impeller. FIG. 5B is a view of FIG. 5A as seen from the arrow A. FIG. 5B is a diagram showing another embodiment of a thrust load reduction structure. FIG. 7A is a diagram showing a rotor arranged offset with respect to a stator. FIG. 7B is a diagram showing a rotor arranged offset with respect to a stator. FIG. 7A is a diagram showing an embodiment of a bearing having a tapered structure. FIG. 7B is a diagram showing another embodiment of a bearing having a tapered structure. FIG. 13A is a diagram showing a motor pump as a comparative example. FIG. 13B is a diagram showing another embodiment of a motor pump. FIG. 13C is a diagram showing another embodiment of the motor pump. FIG. 13D is a diagram showing another embodiment of a balance adjustment method. FIG. 13E is a diagram showing another embodiment of the balance adjustment method. FIG. 13F is a diagram showing another embodiment of the balance adjustment method. FIG. 13G is a diagram showing another embodiment of the balance adjustment method. FIG. 13H is a diagram showing another embodiment of the balance adjustment method. FIG. 13I ... jig. FIG. 21A is a perspective view showing another embodiment of the pump unit. FIG. 21B is a plan view of the pump unit shown in FIG. 21A. FIG. 21I is a diagram showing a control flow of the motor pump by a control device. FIG. 21I is a diagram showing another embodiment of the impeller. FIG. 21I is a diagram showing another embodiment of the impeller. FIG. 21I is a diagram showing a seal member arranged between the cover and the side plate. FIG. 21I is a diagram showing another embodiment of the impeller. FIG. 21I is a diagram showing another embodiment of the motor pump. FIG. 21I is a diagram showing another embodiment of the motor pump. FIG. 21I is a diagram showing a motor pump in which various components can be selected depending on operating conditions.FIG. 31A is a cross-sectional view of a motor pump according to another embodiment. FIG. 31B is a view of the motor pump shown in FIG. 31A when viewed from the axial direction. FIG. 32A is a cross-sectional view of a motor pump according to another embodiment. FIG. 32B is a front view of the suction casing of the motor pump shown in FIG. 32A. FIG. 32B is a view showing a pump unit including motor pumps connected in series. FIG. 32C is a view showing an impeller according to another embodiment. FIG. 32D is a view showing an impeller according to another embodiment. FIG. 32E is a view showing a rotor inserted into the rotor holder. FIG. 32F is a view showing a rotor inserted into the rotor holder. FIG. 32G is a view showing an impeller according to another embodiment. FIG. 32H is a view showing a rotor inserted into the rotor holder. FIG. 32I is a view showing an impeller according to another embodiment. FIG. 32I is a view showing a rotor holder according to another embodiment. FIG. 32I is a view showing a rotor inserted into the rotor holder. FIG. 32I is a view showing an impeller according to another embodiment. FIG. 32I is a view showing a rotor holder according to another embodiment. FIG. 32I is a view showing a rotor FIG. 10 is a diagram showing another embodiment of the motor pump.

[0017] Hereinafter, embodiments of the motor pump will be described with reference to the drawings. In the following embodiments, the same or corresponding components are designated by the same reference numerals, and redundant description will be omitted.

[0018] Fig. 1 is a diagram showing one embodiment of a motor pump. As shown in Fig. 1, the motor pump MP includes an impeller 1, an annular rotor 2 fixed to the impeller 1, a stator 3 arranged radially outside the rotor 2, and a bearing 5 that supports the impeller 1. The impeller 1 has a flow passage formed therein, and the bearing 5 is arranged outside the flow passage (e.g., an inlet flow passage) of the impeller 1.

[0019] In the embodiment shown in Figure 1, the motor pump MP is a rotary machine equipped with a permanent magnet motor, but the type of motor pump MP is not limited to this embodiment. In one embodiment, the motor pump MP may be equipped with an induction motor or a reluctance motor. If the motor pump MP is equipped with a permanent magnet motor, the rotor 2 is a permanent magnet. If the motor pump MP is equipped with an induction motor, the rotor 2 is a squirrel-cage rotor.

[0020] In the embodiment shown in Figure 1, the impeller 1 is a centrifugal impeller. More specifically, the impeller 1 includes a disk-shaped main plate 10, a side plate 11 disposed opposite the main plate 10, and a plurality of blades 12 disposed between the main plate 10 and the side plate 11. A motor pump MP including the impeller 1 as a centrifugal impeller has superior lift characteristics and can generate high pressure compared to pumps such as axial flow pumps and mixed flow pumps. Furthermore, the motor pump MP in this embodiment can contribute to the rotational stability of the impeller 1 by utilizing the pressure difference generated therein.

[0021] The side plate 11 has a suction portion 15 formed in its central portion and a main body portion 16 connected to the suction portion 15. The suction portion 15 extends in the direction of the center line CL of the motor pump MP, and the main body portion 16 extends in a direction inclined relative to the center line CL (more specifically, vertically). The center line CL is parallel to the flow direction of the liquid (the liquid being handled) that flows when the motor pump MP is operating.

[0022] 1, the side plate 11 has an annular protrusion 17 extending from the outer edge 11a of the side plate 11 (more specifically, the end of the main body 16) toward the suction portion 15. In the embodiment shown in FIG. 1, the main body 16 and the protrusion 17 are integrally configured, but the protrusion 17 may be a separate member from the main body 16.

[0023] The rotor 2 has an inner diameter larger than the outer diameter of the protrusion 17, and is fixed to the outer peripheral surface 17a of the protrusion 17. The stator 3 is disposed so as to surround the rotor 2, and is housed in a stator casing 20. The stator casing 20 is disposed radially outward of the impeller 1.

[0024] The motor pump MP includes a suction casing 21 and a discharge casing 22 arranged on either side of a stator casing 20. The suction casing 21 is arranged on the suction side of the impeller 1, and the discharge casing 22 is arranged on the discharge side of the impeller 1. The impeller 1, the rotor 2, and the bearings 5 ​​are arranged radially inside the stator casing 20, and are arranged between the suction casing 21 and the discharge casing 22.

[0025] The suction casing 21 has a suction port 21a in its central portion. The discharge casing 22 has a discharge port 22a in its central portion. The suction port 21a and the discharge port 22a are arranged in a straight line along the center line CL. Therefore, the liquid sucked in through the suction port 21a and discharged from the discharge port 22a flows in a straight line.

[0026] 1, with the stator casing 20 sandwiched between the suction casing 21 and the discharge casing 22, the worker inserts the through bolts 25 into the suction casing 21 and the discharge casing 22 and tightens the through bolts 25. In this manner, the motor pump MP is assembled.

[0027] When the motor pump MP is operated, the liquid to be treated is sucked in through the suction port 21a of the suction casing 21 (see the black arrow in Figure 1). The rotation of the impeller 1 increases the pressure of the liquid to be treated, and the liquid to be treated flows inside the impeller 1 in a direction perpendicular to the center line CL (i.e., the centrifugal direction). The liquid to be treated that is discharged to the outside of the impeller 1 collides with the inner circumferential surface 20a of the stator casing 20, and the direction of the liquid to be treated is changed. The liquid to be treated then passes through the gap between the back surface of the impeller 1 (more specifically, the main plate 10) and the discharge casing 22, and is discharged from the discharge port 22a.

[0028] As shown in Figure 1, the motor pump MP is provided with return vanes 30 arranged on the back side of the impeller 1. In the embodiment shown in Figure 1, a plurality of return vanes 30 extending spirally are provided. These plurality of return vanes 30 are fixed to the discharge casing 22 and face the main plate 10 of the impeller 1. By providing the return vanes 30, the handled liquid discharged from the impeller 1 is smoothly guided to the discharge port 22a. The return vanes 30 contribute to converting the velocity energy of the handled liquid discharged from the impeller 1 into pressure energy.

[0029] In the embodiment shown in Fig. 1, the motor pump MP is divided into a suction-side region Ra, a discharge-side region Rb, and an intermediate region Rc between the suction-side region Ra and the discharge-side region Rb. The suction-side region Ra is the region between the suction casing 21 (more specifically, the suction port 21a of the suction casing 21) and the impeller 1 (more specifically, the side plate 11 of the impeller 1). The discharge-side region Rb is the region between the discharge casing 22 (more specifically, the discharge port 22a of the discharge casing 22) and the impeller 1 (more specifically, the main plate 10 of the impeller 1). A plurality of blades 12 are arranged in the intermediate region Rc.

[0030] The rotor 2 and bearing 5 are disposed in the suction-side region Ra of the impeller 1. In this embodiment, the impeller 1 includes a side plate 11 having a tapered shape that widens from the suction-side region Ra toward the discharge-side region Rb. Therefore, a space (dead space) is formed in the suction-side region Ra of the impeller 1. According to this embodiment, by disposing the rotor 2 and bearing 5 in the suction-side region Ra, the motor pump MP can have a structure that effectively utilizes the dead space, resulting in a compact structure.

[0031] The bearing 5 comprises a rotating-side bearing body 6 attached to the protrusion 17 of the side plate 11, and a fixed-side bearing body 7 attached to the suction casing 21. The fixed-side bearing body 7 is disposed on the suction side of the rotating-side bearing body 6. The rotating-side bearing body 6 is a rotating member that rotates together with the rotation of the impeller 1, and the fixed-side bearing body 7 is a stationary member that does not rotate even when the impeller 1 rotates.

[0032] The rotating-side bearing body 6 has a cylindrical portion 6a with an outer diameter smaller than the inner diameter of the protrusion 17, and a flange portion 6b that protrudes outward from the cylindrical portion 6a. Therefore, the cross section of the rotating-side bearing body 6 is L-shaped. A seal member (e.g., an O-ring) 31 is arranged between the inner circumferential surface 17b of the protrusion 17 and the cylindrical portion 6a.

[0033] The rotating-side bearing body 6 is attached to the protrusion 17 of the impeller 1 with the seal member 31 attached to its cylindrical portion 6a. By attaching the rotating-side bearing body 6, the rotor 2 is disposed adjacent to the flange portion 6b of the rotating-side bearing body 6.

[0034] The fixed-side bearing body 7 includes a cylindrical portion 7a disposed opposite the cylindrical portion 6a of the rotating-side bearing body 6, and a flange portion 7b disposed opposite the flange portion 6b of the rotating-side bearing body 6. The cross section of the fixed-side bearing body 7 is L-shaped, similar to the cross section of the rotating-side bearing body 6. Seal members 32 and 33 are disposed between the cylindrical portion 7a of the fixed-side bearing body 7 and the suction casing 21. In this embodiment, two seal members 32 and 33 are disposed, but the number of seal members is not limited to this embodiment.

[0035] 2 is a diagram showing the flow of the liquid passing through the gap between the rotating-side bearing and the fixed-side bearing. The pressure of the liquid is increased by the rotation of the impeller 1, so the pressure of the liquid in the discharge-side region Rb is greater than the pressure of the liquid in the suction-side region Ra. Therefore, a portion of the liquid discharged from the impeller 1 flows back into the suction-side region Ra (see the black arrow in FIG. 2).

[0036] More specifically, a portion of the handled liquid passes through the gap between the stator casing 20 and the rotor 2 and flows into the gap between the flange portion 6b of the rotating side bearing body 6 and the flange portion 7b of the fixed side bearing body 7.

[0037] FIG. 3 is a diagram showing one embodiment of multiple grooves formed in the flange portion of the fixed-side bearing body. As shown in FIG. 3, the fixed-side bearing body 7 has multiple grooves 40 formed in the flange portion 7b. These multiple grooves 40 are formed on the surface of the flange portion 7b facing the flange portion 6b of the rotating-side bearing body 6. The multiple grooves 40 are formed to generate dynamic pressure of the handled liquid in the gap between the flange portions 7b and 6b. In this embodiment, the multiple grooves 40 are spiral grooves extending in a spiral shape. In another embodiment, the multiple grooves 40 may be radial grooves extending radially. By forming the multiple grooves 40, the bearing 5 can support the thrust load of the impeller 1 without contact.

[0038] 3, the plurality of grooves 40 are formed in the flange portion 7b, but in one embodiment, the plurality of grooves 40 may be formed in the flange portion 6b of the rotating-side bearing body 6. Even with such a formation, the bearing 5 can support the thrust load of the impeller 1 in a non-contact manner.

[0039] Fig. 4A is a diagram showing one embodiment of a plurality of grooves formed in a cylindrical portion of a fixed-side bearing body. Fig. 4A shows a plurality of grooves 41 as viewed from the direction of the center line CL. The fixed-side bearing body 7 may have a plurality of grooves 41 formed in the cylindrical portion 7a along the circumferential direction of the cylindrical portion 7a. In the embodiment shown in Fig. 4A, the plurality of grooves 41 are arranged at equal intervals, but they may also be arranged at unequal intervals.

[0040] These grooves 41 are formed on the surface of the cylindrical portion 7a that faces the cylindrical portion 6a of the rotating-side bearing body 6, and extend parallel to the cylindrical portion 7a (i.e., the direction of the center line CL). In the embodiment shown in FIG. 4A , each of the grooves 41 has an arc-shaped recessed shape when viewed from the direction of the center line CL. The shape of the grooves 41 is not limited to this embodiment. In one embodiment, each of the grooves 41 may have a concave recessed shape when viewed from the direction of the center line CL.

[0041] 4B and 4C are diagrams showing another embodiment of a groove formed in the cylindrical portion of the fixed-side bearing body. As shown in FIGS. 4B and 4C , the fixed-side bearing body 7 has an annular groove 42 formed in the cylindrical portion 7a along the circumferential direction of the cylindrical portion 7a. The groove 42 is formed in a portion of the cylindrical portion 7a and has a concave shape when viewed perpendicular to the center line CL (see FIGS. 4B and 4C ). Cylindrical portions 7a are present at both ends 42a, 42a of the groove 42 in the center line CL direction. With this structure, even if a radial load acts on the impeller 1, the fixed-side bearing body 7 (more specifically, the cylindrical portion 7a) can reliably support the impeller 1 via the rotating-side bearing body 6. The length of the groove 42 in the center line CL direction is not particularly limited. In the embodiment shown in FIGS. 4B and 4C , the fixed-side bearing body 7 has a single groove 42. However, in one embodiment, the fixed-side bearing body 7 may have multiple grooves 42 arranged along the center line CL direction.

[0042] The liquid that passes through the gap between the flange portions 6b and 7b flows into the gap between the cylindrical portions 6a and 7a. When the rotating-side bearing body 6 rotates together with the impeller 1, viscous resistance is generated in the liquid that flows through this gap. This viscous resistance may have a negative effect on the operating efficiency of the motor pump MP.

[0043] As shown in the above-described embodiment, by forming the plurality of grooves 41 (or grooves 42), the size of the narrow region formed in the gap between the cylindrical portion 6 a and the cylindrical portion 7 a is reduced. Therefore, the viscous resistance generated in the handled liquid can be reduced. Furthermore, by forming the plurality of grooves 41 (or grooves 42), dynamic pressure is generated in the handled liquid, and the bearing 5 can support the radial load of the impeller 1 without contact. The effect of reducing the viscous resistance by reducing the size of the narrow region formed between the flange portion 6 b and the flange portion 7 b can also be achieved by providing the plurality of grooves 40 (see FIG. 3 ).

[0044] 4A to 4C, the grooves 41, 42 are formed in the cylindrical portion 7a, but in one embodiment, the grooves 41, 42 may be formed in the cylindrical portion 6a of the rotating-side bearing body 6. Even with such a formation, the bearing 5 can support the radial load of the impeller 1 in a non-contact manner.

[0045] As shown in Figure 2, the treated liquid that passes through the gap between the cylindrical portion 6a of the rotating-side bearing body 6 and the cylindrical portion 7a of the fixed-side bearing body 7 passes through the gap between the side plate 11 of the impeller 1 and the suction casing 21, and is returned to the suction side of the motor pump MP. In this embodiment, the bearing 5 is disposed in the path of the leakage flow of the treated liquid. With this configuration, a portion of the treated liquid flows into the minute gap between the rotating-side bearing body 6 and the fixed-side bearing body 7, and as a result, the motor pump MP can suppress leakage of the treated liquid.

[0046] As described above, the pressure of the liquid in the discharge region Rb is greater than the pressure of the liquid in the suction region Ra. Therefore, a thrust load acts on the impeller 1 from the discharge port 22a of the discharge casing 22 toward the suction port 21a of the suction casing 21 (see the outline arrow in FIG. 1). The motor pump MP according to this embodiment has a structure that reduces the thrust load.

[0047] FIG. 5A is a diagram showing one embodiment of a thrust load reduction structure provided on the rear surface of the impeller. FIG. 5B is a view of FIG. 5A as viewed from the arrow A. As shown in FIGS. 5A and 5B , the motor pump MP includes a thrust load reduction structure 45 provided on the rear surface of the impeller 1 (more specifically, the main plate 10). In the embodiment shown in FIGS. 5A and 5B , the thrust load reduction structure 45 is a plurality of spirally extending rear vanes 46 attached to the main plate 10. These rear vanes 46 can generate a load in the opposite direction to the thrust load due to rotation of the impeller 1. As a result, the thrust load reduction structure 45 can reduce the thrust load generated in the motor pump MP.

[0048] FIG. 6 is a diagram showing another embodiment of the thrust load reduction structure. As shown in FIG. 6, the thrust load reduction structure 45 may be a structure having a plurality of notches formed along the circumferential direction of the impeller 1 (more specifically, the main plate 10) and extending toward the center of the impeller 1. In the embodiment shown in FIG. 6, a plurality of notches 47 are formed in the main plate 10 of the impeller 1. By forming the plurality of notches 47, the contact area of ​​the treated liquid with the main plate 10 is reduced. As a result, the thrust load reduction structure 45 can reduce the thrust load generated in the motor pump MP. Although not shown, the embodiment shown in FIG. 5 and the embodiment shown in FIG. 6 may be combined.

[0049] In this embodiment, the impeller 1 is always subjected to a thrust load from the discharge side toward the suction side. Furthermore, the bearing 5 supports the impeller 1, which generates a rotational force. Therefore, the parallelism of the impeller 1 itself is maintained, and wobbling of the impeller 1 can be suppressed. As a result, the motor pump MP can continue to operate stably with a structure in which only a single bearing 5 is disposed in the suction side region Ra (i.e., a single bearing structure).

[0050] In one embodiment, at least one of the impeller 1 and the bearing 5 may be made of a lightweight material. Examples of lightweight materials include resin and metals with low specific gravity (e.g., aluminum alloys, magnesium alloys, titanium alloys, etc.). Such a structure can reduce the weight of the motor pump MP itself and further reduce the size of the bearing 5 (and impeller 1). Note that the materials of the components that come into contact with the liquid (i.e., liquid-contacting components), such as the impeller 1 and bearing 5, are not particularly limited and can be changed to any suitable material depending on the liquid quality.

[0051] Furthermore, in this embodiment, the multiple return vanes 30 (see FIG. 1) can reduce the radial load generated on the impeller 1. The multiple return vanes 30 are arranged at equal intervals along the circumferential direction of the discharge port 22a. With this arrangement, the radial load is distributed evenly, and as a result, the radial load generated on the impeller 1 is reduced.

[0052] In this embodiment, the motor pump MP is equipped with a permanent magnet motor. Therefore, when the motor pump MP starts, a certain load acts on the bearing 5 to convert the repulsive force caused by the magnetic force into a rotational force. This load is a force generated in the rotor 2, and the bearing 5 supports this load.

[0053] 7A and 7B are diagrams showing a rotor that is offset relative to the stator. When the rotor 2 is offset toward the discharge side relative to the stator 3 as shown in Fig. 7A, the impeller 1 receives a force that acts in a direction that moves the rotating-side bearing 6 toward the fixed-side bearing 7 due to the influence of a magnetic force generated between the rotor 2 and the stator 3 (see the arrow in Fig. 7A). This arrangement makes it possible to adjust (increase) the thrust load of the rotating-side bearing 6 that acts on the fixed-side bearing 7.

[0054] As shown in Figure 7B, when the rotor 2 is positioned shifted toward the suction side with respect to the stator 3, the impeller 1 receives a force acting in a direction that moves the rotating-side bearing 6 away from the fixed-side bearing 7 due to the influence of a magnetic force generated between the rotor 2 and the stator 3 (see Figure 7B). With this arrangement, it is possible to adjust (reduce) the thrust load of the rotating-side bearing 6 acting on the fixed-side bearing 7.

[0055] Fig. 8 is a diagram showing one embodiment of a bearing having a tapered structure. In the embodiment shown in Fig. 8, the bearing 5 has a tapered structure in which the gap between the rotating-side bearing body 6 and the fixed-side bearing body 7 extends from the suction side toward the discharge side, in a direction approaching the center line CL (i.e., the center portion of the impeller 1). As shown in Fig. 8, the rotating-side bearing body 6 and the fixed-side bearing body 7 have inclined surfaces 50 and 51 facing each other, respectively. With this configuration, the bearing 5 can concentrate the radial load and thrust load acting on the rotating-side bearing body 6 and the fixed-side bearing body 7 on the inclined surfaces 50 and 51, allowing the bearing 5 to have a simple structure.

[0056] Fig. 9 is a diagram showing another embodiment of a bearing having a tapered structure. In the embodiment shown in Fig. 9, the bearing 5 has a tapered structure in which the gap between the rotating-side bearing body 6 and the fixed-side bearing body 7 extends in a direction away from the center line CL (i.e., the center portion of the impeller 1) from the suction side toward the discharge side. As shown in Fig. 9, the rotating-side bearing body 6 and the fixed-side bearing body 7 each have inclined surfaces 53, 54 facing each other.

[0057] Fig. 10 is a diagram showing a pump unit including a plurality of motor pumps. As shown in Fig. 10, the pump unit PU may include a plurality of motor pumps MP arranged in series and an inverter 60 that controls the operation of each of the plurality of motor pumps MP. In the embodiment shown in Fig. 10, each of the plurality of motor pumps MP has the same structure as the structure shown in the above-described embodiment. Therefore, a detailed description of the motor pumps MP will be omitted.

[0058] 10, the pump unit PU includes three motor pumps MP, but the number of motor pumps MP is not limited to this embodiment. As described above, the suction ports 21a and discharge ports 22a of the pump units PU are arranged in a straight line along the center line CL. Therefore, multiple motor pumps MP can be arranged consecutively in a straight line, and the pump unit PU can easily have a multi-stage motor pump structure.

[0059] As shown in Figure 10, two intermediate casings 61 are disposed between the suction casing 21 disposed adjacent to the first-stage impeller 1A and the discharge casing 22 disposed adjacent to the third-stage impeller 1C. The second-stage impeller 1B is disposed between these intermediate casings 61. Each of the intermediate casings 61 has a common (i.e., similar) structure to the suction casing 21. With the intermediate casings 61 sandwiched between the suction casing 21 and the discharge casing 22, an operator can assemble the pump unit by inserting and tightening through bolts 25 into the suction casing 21, the intermediate casings 61, and the discharge casing 22.

[0060] As shown in Figure 10, one inverter 60 is connected to the stators 3 of multiple motor pumps MP. The inverter 60 can independently control each of the multiple motor pumps MP. This allows the operator to operate at least one motor pump MP at any timing depending on the operating conditions of the pump unit.

[0061] 11 and 12 are views showing another embodiment of the pump unit. In the embodiment shown in Fig. 11 and Fig. 12, the pump unit PU includes a plurality of motor pumps MP arranged in parallel. Although Fig. 11 shows a simplified illustration, each of the plurality of motor pumps MP is installed inside a pipe 65. In Fig. 11, four motor pumps MP are provided, but the number of motor pumps MP is not limited to this embodiment. As shown in Fig. 12, three motor pumps MP may be provided.

[0062] Fig. 13A is a diagram showing a motor pump as a comparative example. Figs. 13B and 13C are diagrams showing other embodiments of the motor pump. As shown in Fig. 13A, the motor pump as the comparative example has a rotation shaft RS, but the motor pump MP according to this embodiment does not have a rotation shaft RS. Instead, the impeller 1 has a rounded protrusion 70 located in its center.

[0063] In the embodiment shown in Fig. 13B, the impeller 1 has a convex portion 70A having a first radius of curvature, and in the embodiment shown in Fig. 13C, the impeller 1 has a convex portion 70B having a second radius of curvature different from the first radius of curvature. Hereinafter, the convex portions 70A and 70B may be referred to simply as convex portion 70 without distinction.

[0064] The protrusion 70 is disposed in the center portion of the main plate 10 and is configured integrally with the main plate 10. In one embodiment, the protrusion 70 may be a member different from the main plate 10. In this case, the protrusion 70 having a different radius of curvature may be replaced depending on the operating conditions of the motor pump.

[0065] The tip 71 of the convex portion 70 has a smooth convex shape, and the liquid to be handled that flows into the impeller 1 comes into contact with the tip 71 of the convex portion 70. By providing the convex portion 70, the flow of the liquid to be handled is not obstructed and is guided smoothly and efficiently to the blades 12. On the other hand, in the motor pump serving as the comparative example, the rotating shaft RS is fixed to the impeller by the nut Nt, and therefore there is a risk that the flow of the liquid to be handled will be obstructed by the nut Nt (and the rotating shaft RS).

[0066] The convex portion 70A shown in Figure 13B has a larger radius of curvature than the convex portion 70B shown in Figure 13C. Increasing the radius of curvature of the convex portion 70 reduces the distance between the convex portion 70 and the side plate 11. Conversely, decreasing the radius of curvature of the convex portion 70 increases the distance between the convex portion 70 and the side plate 11. In this way, by changing the radius of curvature of the convex portion 70, it is possible to adjust the size of the flow path of the impeller 1 for the treated liquid. The flow path of the impeller 1 shown in Figure 13C is larger than the flow path of the impeller 1 shown in Figure 13B.

[0067] According to this embodiment, the motor pump MP does not have a rotating shaft, so the number of parts can be reduced and the size of the flow path can be adjusted. Furthermore, since there is no need to provide a rotating shaft, the impeller 1 can be made compact. As a result, the entire motor pump MP can be made compact.

[0068] When the motor pump is in operation, it rotates the impeller 1 at high speed. If the center of gravity of the impeller 1 is misaligned, the impeller 1 will rotate at high speed in an eccentric state. As a result, noise may be generated, and in the worst case, the motor pump may break down.

[0069] Therefore, the operator performs a balance (dynamic balance) adjustment method to determine the desired position of the center of gravity of the impeller 1. As shown in Fig. 13A, if the rotation shaft RS is attached to the impeller, it is necessary to attach the rotation shaft RS to a testing machine and rotate the impeller together with the rotation shaft RS. In this embodiment, the rotation shaft RS is not attached to the impeller 1, so the operator can perform the balance adjustment method described below.

[0070] 14 to 18 are diagrams showing one embodiment of a balance adjustment method. As shown in Fig. 14, first, an operator performs a step of forming a through hole 10a in the center of the impeller 1 (more specifically, in the main plate 10). Then, as shown in Fig. 15, the operator inserts a shaft 76 of a balance adjustment jig 75 into the through hole 10a. The shaft 76 of the balance adjustment jig 75 corresponds to the rotation axis.

[0071] 16, the worker places a fixture 77 on the back side of the impeller 1 and fastens the shaft 76 to the fixture 77. In this state, the worker rotates the impeller 1 together with the balance adjustment jig 75, determines the position of the center of gravity of the impeller 1, and then performs the process of adjusting the position of the center of gravity. In this way, the balance adjustment jig 75 has a structure that supports the center of the impeller 1. Therefore, the balance adjustment jig 75 may also be called a center support adjustment jig.

[0072] After determining the desired position of the center of gravity of the impeller 1, the operator pulls out the shaft 76 of the balancing jig 75 and then inserts the center cap 80 into the through hole 10a to close it (see FIGS. 17 and 18 ). The center cap 80 has a rounded shape, similar to the convex portion 70 according to the embodiment shown in FIGS. 13B and 13C . Therefore, the flow of the treated liquid is not obstructed and it is guided smoothly and efficiently to the blades 12.

[0073] Fig. 19 is a diagram showing another embodiment of the balance adjustment jig. In the embodiment shown in Fig. 18, the balance adjustment jig 75 has a structure that supports the center of the impeller 1. In the embodiment shown in Fig. 19, the balance adjustment jig 85 includes a supporter 86 that supports the rotating-side bearing body 6 of the bearing 5, and a shaft portion 87 fixed to the supporter 86. In this way, the balance adjustment jig 85 has a structure that supports the end of the impeller 1. Therefore, the balance adjustment jig 85 may also be called an edge support adjustment jig.

[0074] The supporter 86 has an annular shape with an outer diameter smaller than the inner diameter of the rotation-side bearing body 6, and by inserting the supporter 86 into the rotation-side bearing body 6, the balance adjustment jig 85 supports the impeller 1 via the rotation-side bearing body 6. In this state, the worker performs a process of rotating the impeller 1 together with the balance adjustment jig 85. Thereafter, with the impeller 1 rotating, the worker determines the position of the center of gravity of the impeller 1 and performs a process of adjusting the position of the center of gravity.

[0075] According to the embodiment shown in Fig. 19, the worker does not need to form the through hole 10a. In the embodiment shown in Fig. 19, the impeller 1 may also have a protrusion 70 formed at its center (see Figs. 13A and 13B).

[0076] Fig. 20 is a diagram showing another embodiment of the balance adjustment method. As shown in Fig. 20, the rotor 2 includes an annular iron core 2a and a plurality of magnets 2b embedded in the iron core 2a. The plurality of magnets 2b are arranged at equal intervals along the circumferential direction of the rotor 2 (more specifically, the iron core 2a). An operator performs a step of forming a plurality of weight insertion holes 90 along the circumferential direction of the rotor 2. This step of forming the weight insertion holes 90 is performed during the manufacture of the iron core 2a.

[0077] The weight insertion holes 90 are formed between adjacent magnets 2b. The worker performs a step of determining the center of gravity position of the impeller 1, and determines the current center of gravity position of the impeller 1. If the center of gravity position of the impeller 1 is misaligned, the worker performs a step of inserting a weight 91 into at least one of the plurality of weight insertion holes 90 to adjust the center of gravity position.

[0078] In one embodiment, if the center of gravity of the impeller 1 is shifted, instead of inserting the weight 91 into the weight insertion hole 90, the operator may remove the excess weight that is causing the center of gravity of the impeller 1 to shift.

[0079] Fig. 21A is a perspective view showing another embodiment of the pump unit. Fig. 21B is a plan view of the pump unit shown in Fig. 21A. As shown in Fig. 21A and Fig. 21B, the pump unit PU includes a plurality of motor pumps MP (three in this embodiment), a control device 100 that operates the plurality of motor pumps MP at variable speeds, and a current sensor 101 that is electrically connected to the control device 100 and detects the current supplied to the plurality of motor pumps MP.

[0080] In this embodiment, two current sensors 101 are provided, but it is also possible to provide at least one current sensor 101. Examples of the current sensor 101 include a Hall element and a CT (current transformer).

[0081] The pump unit PU includes power lines 105 and signal lines 106 extending from the multiple motor pumps MP, and a protective cover 107 that protects the current sensor 101, the power lines 105, and the signal lines 106. The power lines 105 and the signal lines 106 are electrically connected to the inverter 60.

[0082] U-phase, V-phase, and W-phase copper bars (in other words, current-carrying plates, copper plates) 108 are hung between the multiple motor pumps MP, and the current sensor 101 is connected to one of these copper bars 108. Each motor pump MP is provided with a terminal block 102, and the copper bar 108 is connected to the terminal block 102.

[0083] The control device 100 is electrically connected to the inverter 60 and is configured to control the operation of the motor pump MP via the inverter 60. The control device 100 may be disposed outside the inverter 60 or inside the inverter 60.

[0084] The control device 100 includes a signal receiving unit 100a that receives a signal from the current sensor 101 via a signal line 106, a memory unit 100b that stores information regarding the operation of the motor pump MP and an operating program, and a control unit 100c that controls the operation of the motor pump MP based on the data received by the signal receiving unit and the data stored in the memory unit.

[0085] In this embodiment, the pump unit PU includes one inverter 60 for the multiple motor pumps MP, but the pump unit PU may include inverters 60 whose number corresponds to the number of motor pumps MP. When multiple motor pumps MP are provided, each of the multiple inverters 60 controls the operation of each of the multiple motor pumps MP via the control device 100.

[0086] As described above, the motor pump MP has a compact structure that makes effective use of dead space. Therefore, by connecting a plurality of motor pumps MP in series, the pump unit PU can operate at a high head without increasing its installation area.

[0087] The motor pump MP is a rotating machine equipped with a permanent magnet motor. Such a motor rotates uncontrolled when a voltage is forcibly applied at startup. Control of the rotational speed of the motor pump MP by the inverter 60 immediately begins, and then the motor pump MP begins steady-state operation.

[0088] In this embodiment, the pump unit PU includes a plurality of motor pumps MP. Therefore, there is no problem if the rotational speed difference among the plurality of motor pumps MP is eliminated before control of the rotational speed of the motor pumps MP is started. However, if the rotational speed difference is not eliminated, there is a risk of a start-up failure of the motor pumps MP.

[0089] Generally, the motor pump MP rotates more smoothly as the number of magnetic poles of the rotor 2 increases, and it becomes easier to eliminate differences in rotational speed between multiple motor pumps MP. The motor pump MP in this embodiment has a structure that forms a flow path inside the rotor 2, and the outer diameter of the rotor 2 is designed to be large.

[0090] When the outer diameter of the rotor 2 is large, the size of the rotor 2 in the circumferential direction becomes large, making it easy to arrange multiple magnets and increase the number of magnetic poles. With this configuration, the pump unit PU can eliminate the difference in rotational speed between the multiple motor pumps MP. Furthermore, in this embodiment, by using inexpensive flat magnets, the rotor 2 can be made less expensive than a general motor that uses curved magnets.

[0091] Furthermore, in this embodiment, the motor pump MP has a canned motor structure in which the stator 3 is housed in the stator casing 20, and the distance between the rotor 2 and the stator 3 is greater than in a typical motor. Therefore, the motor pump MP can reduce torque ripple, which refers to the range of torque fluctuation, and as a result, the pump unit PU can eliminate differences in rotational speed between the multiple motor pumps MP.

[0092] In this way, the pump unit PU can eliminate the difference in rotational speed, but it is desirable to operate the motor pump MP more stably when the motor pump MP is started and / or during steady operation.

[0093] Therefore, a method for controlling the motor pumps MP will be described below. In this embodiment, multiple motor pumps MP are connected in series. In this case, if the liquid being handled contains foreign matter, the foreign matter may become entangled in the motor pumps MP (especially the first motor pump MP), which may result in the operation of the pump unit PU being hindered. Furthermore, there is a risk that the difference in rotational speed between the multiple motor pumps MP may not be resolved for some reason.

[0094] 22 is a diagram showing a control flow of the motor pump by the control device. As shown in step S101 of Fig. 22, the control device 100, which is electrically connected to the inverter 60, measures the current values ​​of the multiple motor pumps MP (more specifically, the sum of the current values ​​of the motor pumps MP) during the current operation of the motor pumps MP based on the output current of the inverter 60.

[0095] Thereafter, the control device 100 calculates a lower limit current value based on the expected current value that is expected during normal operation of the motor pump MP (more specifically, during startup and steady operation), and compares the sum of the measured current values ​​(measured current value Amax) with a predetermined lower limit current value (see step S102). In one embodiment, the memory unit 100b of the control device 100 stores the expected current value of each motor pump MP and the expected current values ​​of multiple motor pumps MP. The memory unit 100b may calculate the expected current values ​​of the multiple motor pumps MP from the expected current value of each motor pump MP.

[0096] The control device 100 may determine the "expected current value expected during normal operation" based on at least one of the rated current value and allowable current value of each motor pump MP, or may determine the "expected current value expected during normal operation" based on the current value when multiple motor pumps MP are operating.

[0097] In one embodiment, the control device 100 determines the lower limit current value based on the number of motor pumps MP. For example, the lower limit current value can be calculated using the following formula: Lower limit current value = Estimated current value of multiple motor pumps MP × (1 - 1 / number n of motor pumps) In this embodiment, because three motor pumps MP are installed, the lower limit current value is ⅔ of the estimated current value.

[0098] After step S102, the control device 100 compares the calculated lower limit current value with the measured current value (see step S103). More specifically, the control device 100 determines whether the measured current value is lower than the lower limit current value (measured current value Amax>lower limit current value).

[0099] If the measured current value is lower than the lower limit current value (see "YES" in step S103), in this embodiment, if the measured current value is lower than two-thirds of the expected current value (i.e., the lower limit current value), the control device 100 determines that an abnormality has occurred in at least one of the multiple motor pumps MP (see step S104).If the measured current value is not lower than the lower limit current value (see "NO" in step S103), the control device 100 repeats steps S102 and S103.

[0100] When the control device 100 determines that an abnormality has occurred, the control device 100 may issue an alarm while continuing to operate the motor pump MP, or may stop operation of the motor pump MP and issue an alarm.

[0101] Such a control flow may be performed when the motor pump MP is started up, or may be performed during steady operation of the motor pump MP. When the control flow is performed when the motor pump MP is started up, the measured current value corresponds to the starting current value at the start of the multiple motor pumps MP, and the assumed current value is the current value assumed at the normal start of the multiple motor pumps MP.

[0102] When the control flow is performed during steady-state operation of the motor pump MP, the measured current value corresponds to the operating current value during steady-state operation of the multiple motor pumps MP, and the expected current value is the current value expected during normal steady-state operation of the multiple motor pumps MP.

[0103] The starting current value and the operating current value may be the same or different. Similarly, the expected current value expected during normal startup and the expected current value expected during normal steady operation may be the same or different.

[0104] In one embodiment, the control device 100 may determine the estimated current value based on the flow rates on the discharge sides of the multiple motor pumps MP. In this case, the pump unit PU includes a flow rate sensor (not shown) that detects the flow rate of the liquid being pumped, and the flow rate sensor is electrically connected to the control device 100.

[0105] The memory unit 100b of the control device 100 stores data indicating the correlation between the flow rate of the handled liquid during normal operation and the current supplied to the multiple motor pumps MP during normal operation. The control device 100 determines an expected current value based on this data, and calculates a lower limit current value based on the determined expected current value. The above calculation formula can be cited as an example of a formula for calculating the lower limit current value.

[0106] The control device 100 compares the measured current value during steady-state operation of multiple motor pumps MP with the lower limit current value, and if the measured current value is lower than the lower limit current value, it determines that an abnormality has occurred in at least one of the multiple motor pumps MP.

[0107] In one embodiment, the control device 100 may determine the estimated current value based on the pressures on the discharge sides of the multiple motor pumps MP. In this case, the pump unit PU includes a pressure sensor (not shown) that detects the pressure of the pumped liquid, and the pressure sensor is electrically connected to the control device 100.

[0108] The memory unit 100b of the control device 100 stores data showing the correlation between the pressure of the handled liquid and the current supplied to the multiple motor pumps MP during normal operation. The control device 100 determines an expected current value based on this data, and calculates a lower limit current value based on the determined expected current value. The above calculation formula can be used as an example of a formula for calculating the lower limit current value.

[0109] The control device 100 compares the measured current value during steady-state operation of multiple motor pumps MP with the lower limit current value, and if the measured current value is lower than the lower limit current value, it determines that an abnormality has occurred in at least one of the multiple motor pumps MP.

[0110] In the embodiment shown in Figures 21A and 21B, the pump unit PU is equipped with a current sensor 101 (first current sensor 101) arranged between the first motor pump MP (first motor pump MP) and the second motor pump MP (second motor pump MP), and a current sensor 101 (second current sensor 101) arranged between the second motor pump MP and the third motor pump MP (third motor pump MP).

[0111] Therefore, the control device 100 can measure the current value of the first motor pump MP (i.e., the measured current value Aa1) based on the signal sent from the first current sensor 101, and can measure the sum of the measured current value Aa1 of the first motor pump MP and the measured current value Aa2 of the second motor pump MP (i.e., the measured current value Ab (= Aa1 + Aa2)) based on the signal sent from the second current sensor 101.

[0112] The control device 100 compares the measured current value Aa1 with the expected current value expected during normal operation of each motor pump MP (at start-up, during steady-state operation), and if the measured current value Aa1 is lower than the expected current value (Aa1 < expected current value), it determines that an abnormality has occurred in the first motor pump MP.

[0113] The control device 100 compares the measured current value Aa1 with the expected current value expected during normal operation (startup, steady-state operation) of each motor pump MP, and if the measured current value Aa1 is greater than the expected current value (Aa1 > expected current value) and the value obtained by subtracting the measured current value Aa1 from the measured current value Ab (i.e., Ab - Aa1) is less than the expected current value ((Ab - Aa1) < expected current value), it determines that an abnormality has occurred in the second motor pump MP. The value obtained by subtracting the measured current value Aa1 from the measured current value Ab corresponds to the measured current value Aa2.

[0114] If the control device 100 determines that the measured current value Amax is lower than the lower limit current value and determines that no abnormality has occurred in the first motor pump MP or the second motor pump MP, it determines that an abnormality has occurred in the third motor pump MP.

[0115] When the pump unit PU has four motor pumps MP connected in series, the pump unit PU has a current sensor 101 (third current sensor 101) arranged between the third motor pump MP and the fourth motor pump MP (fourth motor pump MP).

[0116] The control device 100 can measure the sum (i.e., the measured current value Ac) of the measured current value Aa1 of the first motor pump MP, the measured current value Aa2 of the second motor pump MP, and the measured current value Aa3 of the third motor pump MP based on the signal sent from the third current sensor 101.

[0117] The control device 100 determines that an abnormality has occurred in the third motor pump MP if the measured current value Aa1 is greater than the expected current value (Aa1 > expected current value), the value obtained by subtracting the measured current value Aa1 from the measured current value Ab (i.e., Ab - Aa1) is greater than the expected current value ((Ab - Aa1) > expected current value), and the value obtained by subtracting the measured current value Ab from the measured current value Ac (i.e., Ac - Ab, where Ab = Aa1 + Aa2) is lower than the expected current value. The value obtained by subtracting the measured current value Ab from the measured current value Ac corresponds to the expected current value Aa3.

[0118] If the control device 100 determines that the measured current value Amax is lower than the lower limit current value and that no abnormalities have occurred in the first motor pump MP, second motor pump MP, and third motor pump MP, it determines that an abnormality has occurred in the fourth motor pump MP. Note that even if the pump unit PU is equipped with five or more motor pumps MP connected in series, the control device 100 can determine whether an abnormality has occurred in each motor pump MP using a method similar to that described above.

[0119] In the above embodiment, the method for controlling a plurality of motor pumps MP connected in series has been described, but the pump unit PU may also control a plurality of motor pumps MP connected in parallel. When controlling a plurality of motor pumps MP connected in parallel (see FIGS. 11 and 12), the control device 100 may be configured to stagger the start timings of the plurality of motor pumps MP.

[0120] By staggering the start timing, the pump unit PU can form a swirling flow in the pipe 65. By forming a swirling flow, foreign matter and air adhering to the pipe 65 can be removed, and further, stagnation of the handled liquid can be prevented.

[0121] To form a swirl flow, the control device 100 may start one of the multiple motor pumps MP (first motor pump MP) and then start the motor pump MP (second motor pump MP) adjacent to the started motor pump MP (i.e., first motor pump MP). By successively starting adjacent motor pumps MP in this way, the pump unit PU can form a swirl flow that swirls in the order in which the motor pumps MP are started.

[0122] For example, if three motor pumps MP are installed, the control device 100 may start the first motor pump MP and then start the second motor pump MP, or may start the third motor pump MP and then start the first motor pump MP adjacent to the third motor pump MP.

[0123] Figure 23 is a diagram showing another embodiment of the impeller. In this embodiment, the bearing 5 is not shown. In the above-described embodiment, the impeller 1 includes an annular protrusion 17 extending from the outer edge 11a of the side plate 11 toward the suction portion 15 (see Figure 1). In the embodiment shown in Figure 23, the side plate 11 of the impeller 1 has an annular protrusion 117 arranged radially inward of the outer edge 11a of the side plate 11.

[0124] The rotor 2 is disposed in an annular step formed between the outer edge 11a of the side plate 11 and the protrusion 117, and the exposed portion of the rotor 2 is covered by a cover 110. The cover 110 is one of the components of the motor pump MP. Examples of the cover 110 include a corrosion-resistant can, a resin coating, or a Ni-plating coating.

[0125] In one embodiment, the iron core 2 a of the rotor 2 is joined to the protrusions 117 by means of adhesive, press fitting, shrink fitting, welding, etc. Similarly, the cover 110 is joined to the impeller 1 by means of adhesive, press fitting, shrink fitting, welding, etc.

[0126] Figure 24 is a diagram showing another embodiment of the impeller. In this embodiment, the bearing 5 is not shown. As shown in Figure 24, the impeller 1 may include an annular mounting portion 118 arranged radially outward of the protrusion 117. By inserting the rotor 2 into the annular space between the mounting portion 118 and the protrusion 117, the rotor 2 can be more reliably fixed to the side plate 11. In this embodiment as well, the exposed portion of the rotor 2 is covered with the cover 110.

[0127] 25 is a diagram showing a sealing member disposed between the cover and the side plate. In this embodiment, the bearing 5 is not shown. As shown in FIG. 25 , by disposing sealing members (e.g., O-rings) 120 and 121 between the cover 110 and the side plate 11 (more specifically, the outer edge portion 11 a and the protrusion 117 of the side plate 11), it is possible to reliably prevent liquid from coming into contact with the rotor 2.

[0128] The impeller 1 according to the embodiment shown in Figures 1 to 25 is manufactured by means of, for example, casting, stainless steel press molding, resin molding, etc. Similarly, the impeller 1 according to the embodiment shown in Figures 26 to 34 described below may also be manufactured by means of casting, stainless steel press molding, resin molding, etc.

[0129] Figure 26 is a diagram showing another embodiment of the impeller. In this embodiment, the bearing 5 is not shown. As shown in Figure 26, the rotor 2 is fixed to the outer edge portion 11a of the side plate 11 so as to block the flow path (i.e., the outlet flow path) of the impeller 1 formed between the main plate 10 and the side plate 11. In this embodiment, the rotor 2 is also arranged in the suction side region Ra.

[0130] 26, the rotor 2 is not covered with the cover 110, and is made of a corrosion-resistant material. In the above-described embodiment, the rotor 2 does not necessarily have to be covered with the cover 110, and may be made of a corrosion-resistant material. In one embodiment, the rotor 2 may be covered with the cover 110.

[0131] With this configuration, the treated liquid passing through the outlet flow path collides with the inner peripheral surface of the rotor 2, changing the direction of the treated liquid. The treated liquid then passes through the gap between the main plate 10 and the discharge casing 22 and is discharged from the discharge port 22a.

[0132] In the embodiment shown in FIGS. 23 to 26, the rotor 2 and the bearing 5 are also disposed in the suction side region Ra of the impeller 1, so that the motor pump MP has a compact structure.

[0133] Figure 27 is a diagram showing another embodiment of the motor pump. As shown in Figure 27, the motor pump MP includes a first impeller 1A arranged on the suction port 21a side, a second impeller 1B arranged on the discharge port 22a side, and a communication shaft 126 connected to the first impeller 1A and the second impeller 1B. The rotor 2 is fixed to the first impeller 1A, and the stator 3 is arranged radially outward of the rotor 2. A bearing 5 supports the first impeller 1A, and the second impeller 1B is supported by the bearing 5 via the communication shaft 126.

[0134] 27, the motor pump MP includes an intermediate casing 125 disposed between the first impeller 1A and the second impeller 1B. The intermediate casing 125 is an annular partition wall that separates the discharge side of the first impeller 1A from the suction side of the second impeller 1B. In this embodiment, the intermediate casing 125 is fixed to the stator casing 20.

[0135] 27, the motor pump MP has two impellers 1, but the number of impellers 1 is not limited to this embodiment. The motor pump MP may have a plurality of intermediate casings 125 depending on the number of impellers 1. In other words, the motor pump MP may have a plurality of impellers 1, including at least a first impeller 1A and a second impeller 1B.

[0136] Figure 28 shows another embodiment of the motor pump. As shown in Figure 28, the motor pump MP further includes a discharge-side bearing 128 that rotatably supports the communication shaft 126 and is disposed on the discharge side of the second impeller 1B. The discharge-side bearing 128 is attached to the discharge casing 22, and seal members (e.g., O-rings) 127A and 127B are disposed in the gap between the discharge-side bearing 128 and the discharge casing 22. Note that, although the embodiment shown in Figure 28 also includes two impellers 1, the number of impellers 1 is not limited to this embodiment. The motor pump MP may include multiple impellers 1, including at least a first impeller 1A and a second impeller 1B.

[0137] 28, the discharge casing 22 has a flow path 129 that communicates with the discharge port 22a. The flow path 129 is disposed radially outward of the communication shaft 126. The treated liquid discharged from the second impeller 1B is discharged to the outside through the flow path 129 and the discharge port 22a.

[0138] 28, the first impeller 1A and the second impeller 1B are supported not only by the bearing 5 but also by a discharge-side bearing 128. The discharge-side bearing 128 is a radial bearing. With this structure, the motor pump MP can suppress radial displacement of the first impeller 1A and the second impeller 1B.

[0139] Fig. 29 is a diagram showing another embodiment of the motor pump. As shown in Fig. 29, the motor pump MP may include a communication shaft 126 to which one impeller 1 is fixed, and a discharge-side bearing 128 that rotatably supports the communication shaft 126.

[0140] Fig. 30 is a diagram showing a motor pump in which various components can be selected depending on the operating conditions. In Fig. 30, the horizontal axis represents the flow rate, and the vertical axis represents the head. As shown in Fig. 30, the motor pump MP is configured so that optimal components can be selected depending on the various operating conditions (i.e., the magnitude of the flow rate and the magnitude of the head).

[0141] In the embodiment shown in Figure 30, the motor pump MP can be selected from a plurality of different configurations (four in this embodiment) depending on the magnitude of head and the magnitude of flow rate (see MPA to MPD in Figure 30). In this embodiment, the motor pump MP includes a plurality of impellers 1 having different sizes, a plurality of rotors 2 fixed to the plurality of impellers 1 and having different lengths, a plurality of stators 3 having lengths corresponding to the lengths of the plurality of rotors 2, and a plurality of stator casings 20 that house the plurality of stators 3 and have lengths corresponding to the lengths of the plurality of stators 3.

[0142] The motor capacity of the motor pump MP depends on the length Lg of the stator 3. The head of the motor pump MP depends on the diameter D1 of the impeller 1. The flow rate of the motor pump MP depends on the size of the outlet flow path B2 of the impeller 1.

[0143] The plurality of impellers 1 include a plurality of side plates 11 having the same diameter and a plurality of main plates 10 having different diameters. In this specification, the diameter D1 of the impeller 1 corresponds to the diameter of the main plate 10.

[0144] The relationship between motor pump MPA and motor pump MPB will now be described. As shown in Figure 30, motor pump MPA and motor pump MPB have the same motor capacity (i.e., LgA = LgB). Motor pump MPA has a higher head capacity than motor pump MPB (i.e., D1A > D1B). Motor pump MPB has a higher flow capacity than motor pump MPA (i.e., B2B > B2A).

[0145] The relationship between the motor pump MPA and the motor pump MPC will be explained below. The motor pump MPC has a larger motor displacement than the motor pump MPA (i.e., LgC > LgA). The motor pump MPC has the same head capacity as the motor pump MPA (i.e., D1A = D1C). The motor pump MPC has a higher flow capacity than the motor pump MPA (i.e., B2C > B2A).

[0146] The relationship between motor pump MPB and motor pump MPC will now be described. Motor pump MPC has a larger motor capacity than motor pump MPB (i.e., LgC > LgB). Motor pump MPC has a higher head capacity than motor pump MPB (i.e., D1C > D1B). The outlet flow path B2B of the impeller 1 of motor pump MPB is the same size as or larger than the outlet flow path B2C of the impeller 1 of motor pump MPC (i.e., B2B ≥ B2C).

[0147] The relationship between the motor pump MPC and the motor pump MPD will be described below. The motor pump MPC has the same motor capacity as the motor pump MPD (i.e., LgC = LgD). The motor pump MPC has a higher head capacity than the motor pump MPD (i.e., D1C > D1D). The motor pump MPD has a higher flow capacity than the motor pump MPC (i.e., B2D > B2C).

[0148] The relationship between the motor pump MPB and the motor pump MPD will be described. The motor pump MPD has a larger motor displacement than the motor pump MPB (i.e., LgD > LgB). The motor pump MPD has a higher flow capacity than the motor pump MPB (i.e., B2D > B2B). The motor pump MPB has the same head capacity as the motor pump MPD (i.e., D1B = D1D).

[0149] 30, the inner diameter D2 and outer diameter D3 of the stator casing 20 are the same for all motor pumps MP. Therefore, an operator can prepare components of different sizes according to the head capacity and flow capacity, and select the optimum component from the plurality of components based on the operating conditions of the motor pump MP.

[0150] By making the inner diameter D2 and outer diameter D3 of the stator casing 20 the same, the performance of the pump unit PU can be easily changed without changing the size of components that do not depend on the head capacity or flow capacity (e.g., bearings 5, suction casing 21, and discharge casing 22).

[0151] Fig. 31A is a cross-sectional view of a motor pump according to another embodiment, and Fig. 31B is a view of the motor pump shown in Fig. 31A as seen from the axial direction. As shown in Fig. 31A and Fig. 31B, the motor pump MP may include a rotation stopper (in other words, a fall stopper) 130 arranged on the back side of the impeller 1.

[0152] 31B, one swivel stopper 130 is provided, but at least one swivel stopper 130 may be provided. The swivel stopper 130 is fixed to the discharge casing 22 and faces the main plate 10 of the impeller 1. The swivel stopper 130 can prevent the treated liquid discharged from the impeller 1 from swirling between the impeller 1 and the discharge casing 22.

[0153] Fig. 32A is a cross-sectional view of a motor pump according to another embodiment, and Fig. 32B is a front view of a suction casing of the motor pump shown in Fig. 32A. As shown in Fig. 32A and Fig. 32B, the motor pump MP includes a suction casing 141 and a discharge casing 142 each having a flat flange shape.

[0154] In the above-described embodiment, the suction port 21a of the suction casing 21 protrudes from the outer surface of the suction casing 21, and similarly, the discharge port 22a of the discharge casing 22 protrudes from the outer surface of the discharge casing 22. In this embodiment, since the suction casing 141 has a flat flange shape, the suction port 141a is formed on the same plane as the outer surface of the suction casing 141. Similarly, since the discharge casing 142 has a flat flange shape, the discharge port 142a is formed on the same plane as the outer surface of the discharge casing 142.

[0155] With this structure, the connecting pipe 140 connected to the motor pump MP can be directly connected to the suction casing 141. Although not shown, the connecting pipe 140 may also be directly connected to the discharge casing 142 having a flat flange shape.

[0156] With this configuration, there is no need to arrange a member (connecting member) to connect the connecting pipe 140 and the suction casing 141, and the number of parts required to connect the piping (not shown) to the motor pump MP can be reduced.

[0157] Since the connecting member is a member that is expected to leak liquid, eliminating the connecting member can reliably prevent liquid leakage. In this embodiment, although not shown, a sealing member (e.g., an O-ring or a gasket) is arranged between the connecting pipe 140 and the suction casing 141.

[0158] An insertion hole 141b is formed radially outward of the suction port 141a of the suction casing 141, into which a fastener 150 is inserted to fasten the connecting pipe 140 and the suction casing 141. The connecting pipe 140 has a through hole 140a that communicates with the insertion hole 141b. An operator can fasten the connecting pipe 140 and the suction casing 141 together by inserting the fastener 150 into the through hole 140a and the insertion hole 141b.

[0159] A bolt accommodating portion 142b that accommodates the head 25a of the through-bolt 25 is formed radially outward of the discharge port 142a of the discharge casing 142. By accommodating the head 25a of the through-bolt 25 in the bolt accommodating portion 142b, the head 25a can be prevented from protruding from the discharge casing 22.

[0160] In one embodiment, the suction casing 141 may have a bolt receiving portion corresponding to the bolt receiving portion 142 b. That is, at least one of the suction casing 141 and the discharge casing 142 has a bolt receiving portion that receives the head 25 a of the through-bolt 25.

[0161] Fig. 33 is a diagram showing a pump unit including motor pumps connected in series. As shown in Fig. 33, the motor pump MP shown in Fig. 32A and Fig. 32B includes a suction casing 141 and a discharge casing 142 having flat flange shapes, so that the suction casing 141 and the discharge casing 142 arranged adjacent to each other can come into surface contact with each other. The suction casing 141 and the discharge casing 142 that come into surface contact with each other correspond to intermediate casings.

[0162] Although not shown, a seal member (for example, an O-ring or a gasket) is arranged between the suction casing 141 and the discharge casing 142, which are in surface contact with each other.

[0163] According to this embodiment, there is no need to place an intermediate casing 61 (see Figure 10), and a pump unit PU equipped with multiple motor pumps MP can be constructed by the simple task of directly connecting multiple motor pumps MP having the same structure in series.

[0164] The motor pump MP according to this embodiment has simple main components (i.e., impeller 1, rotor 2, stator 3, and bearings 5), and is small and lightweight. Therefore, by using through bolts 25, multiple motor pumps MP arranged in series can be easily fastened together as a single unit.

[0165] Furthermore, by bringing the suction casing 141 and the discharge casing 142 into surface contact with each other, the thermal conductivity of the pump unit PU can be improved, and temperature equilibrium can be achieved among the multiple motor pumps MP. As a result, the pump unit PU can operate stably.

[0166] Figure 34 is a diagram showing another embodiment of the impeller. In the above-described embodiment, the impeller 1 is a centrifugal impeller. More specifically, the impeller 1 includes a main plate 10 extending perpendicular to the center line CL, and the liquid pressurized by the impeller 1 is discharged perpendicular to the center line CL. In the embodiment shown in Figure 34, the impeller 1 is a mixed-flow impeller. More specifically, the impeller 1 includes a main plate 160 inclined at a predetermined angle relative to the center line CL. The main plate 160 is inclined from the suction side toward the discharge side, and the liquid pressurized by the impeller 1 is discharged outward in an oblique direction relative to the center line CL.

[0167] Figure 35 is a diagram showing another embodiment of the motor pump. As shown in Figure 35, the motor pump MP includes a rotor holder 200 that holds a rotor 2, and an impeller 1 that is a press-formed product to which the rotor holder 200 is fixed. In this embodiment, the rotor 2 and bearing 5 are also arranged in the suction side region of the impeller 1 (see Figure 1).

[0168] The impeller 1 includes a main plate 10, a side plate 11, and a plurality of blades 12. The main plate 10, the side plate 11, and the blades 12 are each a press-formed product made of a metal material with excellent ductility. An example of such a metal material is stainless steel. In one embodiment, the main plate 10, the side plate 11, and the blades 12 are press-formed separately and then joined together after forming.

[0169] By constructing the impeller 1 from a press-molded product, it is possible to reduce the overall weight of the impeller 1. Such a reduction in weight of the impeller 1 contributes to reducing (or eliminating) the need for balance (dynamic balance) adjustment to determine the desired position of the center of gravity of the impeller 1. Furthermore, such a configuration allows the distance between the main plate 10 and the side plate 11 to be reduced, which in turn allows the motor pump MP to be made even more compact.

[0170] The rotor holder 200 prevents corrosion of the rotor 2 due to contact with the handled liquid of the rotor 2. The rotor holder 200 includes a press-formed annular housing portion 201 that houses the rotor 2, and an annular closing plate 202 that closes the housing portion 201. The housing portion 201 has an annular concave shape and is disposed concentrically with the impeller 1 about a center line CL. For example, the housing portion 201 may be manufactured by deep drawing.

[0171] The housing 201 is fixed (joined) to the side plate 11 of the impeller 1. In one embodiment, the housing 201 is welded to the side plate 11. In order to easily fix the housing 201 to the impeller 1, the impeller 1 and the housing 201 are preferably made of the same material.

[0172] Fig. 36 is an enlarged view of the rotor holder. As shown in Fig. 36, in order to prevent the liquid to be treated from entering through the gap between the storage section 201 and the closing plate 202, the rotor holder 200 is provided with a seal member (e.g., an O-ring) 205 arranged between the storage section 201 and the closing plate 202. The seal member 205 fixes the closing plate 202 to the storage section 201 by its elastic force.

[0173] In one embodiment, the closure plate 202 may be inserted into the rotor holder 200 by a mechanical insertion method. One example of a mechanical insertion method is to press-fit the closure plate 202 into the rotor holder 200. Another example of a mechanical insertion method is to heat the rotor holder 200 and then insert the closure plate 202 into the thermally expanded rotor holder 200 (shrink-fitting). In this case, to reduce the thermal effect on the magnetic force of the rotor 2 (i.e., thermal demagnetization), it is desirable to magnetize the rotor 2 after inserting the closure plate 202 into the rotor holder 200. Another example of a mechanical insertion method is to insert the closure plate 202 into the rotor holder 200 by cooling-fitting. Another example of a mechanical insertion method is to insert the closure plate 202 into the rotor holder 200 using an adhesive.

[0174] The accommodating portion 201 of the rotor holder 200 comprises an outer annular portion 231, an inner annular portion 232 arranged radially inside the outer annular portion 231, and an annular back portion 233 connecting the outer annular portion 231 and the inner annular portion 232.

[0175] The rotating-side bearing 6 is mounted on the rotor holder 200, and the fixed-side bearing 7 is disposed on the suction side of the rotating-side bearing 6 (see FIG. 35). Seal members 31A and 31B are disposed between the inner annular portion 232 and the cylindrical portion 6a of the rotating-side bearing 6. In this embodiment, two seal members are disposed, but the number of seal members is not limited to this embodiment.

[0176] In order to bring the seal members 31A and 31B into close contact with the inner annular portion 232, the inner annular portion 232 is smoothly processed in the press-molding process of the rotor holder 200. In this way, by going through the press-molding process, it is possible to omit a new additional process for bringing the seal members 31A and 31B into close contact with the inner annular portion 232.

[0177] The accommodation portion 201 (more specifically, the outer annular portion 231 and the inner annular portion 232) extends parallel to the cylindrical portion 6a of the rotating-side bearing body 6, and the cylindrical portion 6a is disposed radially inside the inner annular portion 232 of the rotor holder 200. The flange portion 6b of the rotating-side bearing body 6 extends parallel to the closure plate 202 and is disposed adjacent to the closure plate 202.

[0178] If air is present inside the accommodation portion 201, the expansion of the air inside the accommodation portion 201 may cause the closure plate 202 to move in a direction away from the accommodation portion 201. In this embodiment, the flange portion 6b of the rotating-side bearing body 6 adjacent to the closure plate 202 can limit the movement of the closure plate 202.

[0179] In one embodiment, the rotor holder 200 may include a filler (e.g., grease, potting material, adhesive, etc.) filled into the housing 201 to reduce the amount of air expansion within the housing 201.

[0180] The accommodation portion 201 has an outer surface 201a that contacts the rotating-side bearing body 6, an inner surface 201b that contacts the rotor 2, and corner surfaces 201c formed at the corners of the inner surface 201b. As described above, the rotor holder 200 is a press-molded product, and therefore the corner surfaces 201c are smoothly curved. On the other hand, the rotor 2 is manufactured by stacking laminated cores, which are punched products from steel plates, and therefore the rotor 2 has sharp corners.

[0181] Therefore, even if the rotor 2 is inserted into the accommodation portion 201, the sharp corners of the rotor 2 come into contact with the smooth corner surface 201c, and the entire rotor 2 cannot be in close contact with the back surface portion 233. As a result, the worker may not be able to reliably position the rotor 2 with respect to the rotor holder 200, and may not be able to stably accommodate the rotor 2 in the rotor holder 200.

[0182] Therefore, the rotor holder 200 includes a spacer 203 disposed between the accommodation portion 201 and the rotor 2. In the embodiment shown in FIG. 36 , the spacer 203 is a shim disposed between the rear surface portion 233 and the rotor 2. By disposing the spacer 203, it is possible to prevent the rotor 2 from contacting the corner surface 201 c. As a result, the rotor 2 is accommodated in the rotor holder 200 in close contact with the spacer 203, allowing the worker to reliably position the rotor 2 relative to the rotor holder 200. With this configuration, the worker can stably accommodate the rotor 2 in the rotor holder 200.

[0183] Fig. 37 is a diagram showing another embodiment of the spacer. As shown in Fig. 37, the rotor holder 200 may include a spacer 210 arranged between the accommodation portion 201 and the rotor 2. In the embodiment shown in Fig. 37, the spacer 210 is a protrusion protruding from the rear surface portion 233 of the rotor holder 200.

[0184] Methods for fastening the rotor 2 to the rotor holder 200 include, for example, a fastening method using an adhesive, a shrink fit, and a cold fit. When using a fastening method that involves temperature changes in the rotor 2 and / or the rotor holder 200 (for example, shrink fit or cold fit), it is necessary to appropriately determine the dimensions of the rotor 2 and the rotor holder 200. Therefore, it is preferable to use a fastening method that can be performed at room temperature as a simple fastening method.

[0185] 38 is a diagram showing the rotor inserted into the rotor holder. As shown in Fig. 38, the inner surface 230 of the rotor 2 that comes into contact with the inner annular portion 232 has a polygonal shape (an octagon in this embodiment). Because the inner surface 230 of the rotor 2 has a polygonal shape, when the rotor 2 is inserted into the rotor holder 200 at room temperature, the inner annular portion 232 of the rotor holder 200 can make line contact with the inner surface 230 of the rotor 2.

[0186] This contact prevents the entire rotor 2 from contacting the inner annular portion 232 of the rotor holder 200. Therefore, even if the rotor 2 is press-fitted into the rotor holder 200, the contact area of ​​the rotor 2 with the rotor holder 200 can be reduced, and as a result, deformation of the rotor holder 200 can be prevented.

[0187] Figure 39 is a diagram showing the rotor inserted into the rotor holder. As shown in Figure 39, the inner annular portion 232 may have a plurality of protrusions 235 formed at the contact portion with the rotor 2. The protrusions 235 of the inner annular portion 232 face the inner surface 230 of the rotor 2, and the rotor 2 contacts the protrusions 235. This configuration also reduces the contact area of ​​the rotor 2 with the rotor holder 200, and as a result, deformation of the rotor holder 200 can be prevented.

[0188] Returning to Figure 35, the motor pump MP includes a stator casing 20 that houses the stator 3 and is molded integrally with the stator 3 by resin molding. As shown in Figure 35, the stator 3 includes a stator core 3a and a coil 3b that is wound around the stator core 3a with an insulating material 220 interposed therebetween. Examples of the insulating material 220 include insulating paper and resin. The resin that makes up the stator casing 20 is made of a material that has insulating properties and excellent thermal conductivity (a material similar to the potting material).

[0189] The motor pump MP includes a motor frame 221 that covers the outer peripheral surface of the stator casing 20 and is in contact with the stator 3. The motor frame 221 has through holes 242 through which the power lines 105 and signal lines 106 extending from the coil 3b pass. The motor frame 221 is made of a material with excellent thermal conductivity (e.g., a metal material). In this way, the stator 3 is covered by the stator casing 20, which has excellent thermal conductivity, and is in contact with the motor frame 221, which also has excellent thermal conductivity. Therefore, heat generated from the coil 3b of the stator 3 is dissipated to the outside through the stator casing 20 and the motor frame 221.

[0190] Seal members (e.g., O-rings) 241 that prevent the handled liquid from leaking to the outside are arranged between the suction casing 21 and the discharge casing 22 and the stator casing 20. The stator casing 20 has seal grooves 229 in which the seal members 241 are fitted.

[0191] The stator casing 20 is formed by pouring resin into a mold. By forming a protrusion corresponding to the seal groove 229 in the mold in advance, it is possible to omit the step of newly forming the seal groove 229 after manufacturing the stator casing 20. In one embodiment, seal grooves (not shown) into which the seal members 241 are attached may be formed in the suction casing 21 and the discharge casing 22.

[0192] In this embodiment, the stator casing 20, the return vanes 30, and the partition plate 240 fixed to the return vanes 30 are integrally molded members manufactured by resin molding. The return vanes 30 may have a unique nonlinear shape as a flow path. According to this embodiment, by employing resin molding in which resin is poured into a mold, the stator casing 20, the return vanes 30, and the partition plate 240 can be easily mass-produced integrally.

[0193] In one embodiment, in order to improve heat dissipation from the coil 3b, the stator casing 20 may cover the stator core 3a and the coil 3b covered with potting material. By covering the coil 3b with potting material in this way, the potting material penetrates between the wires that make up the coil 3b, thereby improving the heat dissipation of the coil 3b. In this state, by further covering the stator core 3a and the coil 3b with the resin that makes up the stator casing 20, the heat dissipation of the stator 3 can be further improved.

[0194] Examples of the resin that constitutes the stator casing 20 include a two-component mixed curing resin (e.g., dicyclopentadiene resin) or a heat-curing resin (e.g., epoxy resin) that has excellent fluidity at room temperature. In one embodiment, the strength of the stator casing 20 can be improved by mixing fibers as an additive into the resin. In one embodiment, the thermal conductivity of the stator casing 20 can be improved by mixing a material with high thermal conductivity as an additive. Both the fibers and the material with high thermal conductivity may be mixed as additives into the resin that constitutes the stator casing 20.

[0195] Figure 40 is a diagram showing another embodiment of the impeller. As shown in Figure 40, the motor pump MP includes the impeller 1, which is a resin molded product with a rotor holder 200 integrally molded therein. The impeller 1 is made of resin with a main plate 10, side plates 11, and blades 12 integrally molded therein. In one embodiment, the strength of the impeller 1 can be improved by mixing fiber as an additive into the resin.

[0196] The rotor holder 200 includes an annular resin-molded housing portion 251 that houses the rotor 2, and a ring holder 252 that closes the housing portion 251. The impeller 1 and the housing portion 251 of the rotor holder 200 are integrally molded from resin.

[0197] The ring holder 252 is made of a press-formed corrosion-resistant material (e.g., stainless steel). The ring holder 252 and the rotor 2 are fastened together by a mechanical method such as shrink fitting, cooling fitting, or press fitting. In one embodiment, the ring holder 252 and the rotor 2 may be fastened together by an adhesive.

[0198] When fastening the rotor 2 to the ring holder 252, in order to reduce the press-fit load of the rotor 2, the inner surface 230 of the rotor 2 that comes into contact with the ring holder 252 may have a polygonal shape (see Figure 38), and the ring holder 252 may have multiple protrusions 235 formed at the contact points with the rotor 2 (see Figure 39).

[0199] Figure 41 is an enlarged view of the rotor holder. As shown in Figure 41, ring holder 252 has ring portion 253 having an L-shaped cross section and bent portion 254 bent from ring portion 253. Ring portion 253 of ring holder 252, which is a press-molded product, has smooth corners 257 formed at the bent portion.

[0200] In this embodiment as well, rotor 2 and bearing 5 are disposed in the suction side region (see FIG. 1 ) of impeller 1. Rotation-side bearing body 6 is attached to ring holder 252, and fixed-side bearing body 7 is disposed on the suction side of rotation-side bearing body 6. Seal members 31A, 31B are disposed between ring portion 253 of ring holder 252 and cylindrical portion 6a of rotation-side bearing body 6. In this embodiment as well, ring portion 253 is press-formed, so that an additional step for tightly contacting seal members 31A, 31B with ring portion 253 can be omitted.

[0201] As described above, the rotor 2 has sharp corners. Therefore, even if the rotor 2 is attached to the ring holder 252, the sharp corners of the rotor 2 come into contact with the smooth corner surface 257. As a result, the worker may not be able to stably accommodate the rotor 2 in the rotor holder 200.

[0202] Therefore, the rotor holder 200 includes a spacer 260 disposed between the ring holder 252 and the rotor 2. In the embodiment shown in Fig. 41, the spacer 260 is a shim disposed between the ring holder 252 and the rotor 2. In one embodiment, the spacer 260 may be a protrusion (not shown) protruding from the ring holder 252 (see Fig. 37).

[0203] When manufacturing the rotor holder 200, the ring holder 252 and the rotor 2 attached to the ring holder 252 are set in a mold, and resin is then poured into the mold. With this manufacturing method, the resin that forms the accommodating portion 251 of the rotor holder 200 encases the rotor 2, and as a result, the accommodating portion 251 seals the rotor 2.

[0204] The resin poured into the mold is at a high temperature. Therefore, if the high-temperature resin comes into contact with the rotor 2 attached to the ring holder 252, the rotor 2 will be thermally demagnetized. Therefore, after the rotor holder 200 is manufactured, the rotor 2 needs to be magnetized.

[0205] In this embodiment, the accommodation portion 251 of the rotor holder 200 and the impeller 1 are integrally molded members manufactured by resin molding. The impeller 1 may have a unique nonlinear shape as a flow path, similar to the return blade 30. According to this embodiment, by employing resin molding in which resin is poured into a mold, the accommodation portion 251 of the rotor holder 200 and the impeller 1 can be manufactured integrally and easily in large quantities.

[0206] The ring holder 252 has a rotation prevention structure formed at the connection portion with the housing portion 251. When the motor pump MP is operating, the rotation torque of the rotor 2 is transmitted to the impeller 1. Because the ring holder 252 has a rotation prevention structure, even if the impeller 1 rotates, the ring holder 252 does not rotate relative to the housing portion 251. The specific configuration of the rotation prevention structure will be described below.

[0207] 41 , the housing portion 251 includes a main body portion 255 that surrounds most of the rotor 2, and a bent portion 256 that is bent from the main body portion 255. The ring portion 253 of the ring holder 252 has an embedding hole 253a in which a part of the housing portion 251 (more specifically, the bent portion 256) is embedded. A plurality of these embedding holes 253a are formed along the circumferential direction of the ring holder 252.

[0208] By embedding a part of the bent portion 256 in the embedding hole 253a, the ring holder 252 and the accommodating portion 251 are firmly fastened to each other. This embedding is performed by pouring resin into a mold when the rotor holder 200 is manufactured.

[0209] Similarly, the bent portion 254 of the ring holder 252 has an embedding hole 254a in which a portion of the main body portion 255 of the accommodation portion 251 is embedded. A plurality of these embedding holes 254a are formed along the circumferential direction of the ring holder 252. By embedding a portion of the main body portion 255 in the embedding hole 254a, the ring holder 252 and the accommodation portion 251 are firmly fastened to each other. This embedding is performed by pouring resin into a mold during the manufacture of the rotor holder 200. According to this embodiment, it is possible to mechanically prevent the rotor holder 200 from peeling off from the rotor 2 due to the difference in linear expansion between the rotor 2 and the rotor holder 200 caused by temperature changes.

[0210] Figure 42 shows another embodiment of the anti-rotation structure. As shown in Figure 42, the anti-rotation structure may have bent portions 253b, 254b that are bent in a U-shape. More specifically, ring portion 253 of ring holder 252 has bent portion 253b that is bent in a U-shape, and bent portion 254 has bent portion 254b that is bent in a U-shape. Even with this structure, ring holder 252 and storage portion 251 are firmly fastened to each other. Note that the embodiment shown in Figure 41 and the embodiment shown in Figure 42 may be combined.

[0211] In one embodiment, the anti-rotation structure may be a gear-shaped notch (not shown) formed in each of the ring portion 253 and the bent portion 254. A plurality of such notches are formed along the circumferential direction of the ring holder 252.

[0212] In one embodiment, in order to improve the adhesion between the accommodating portion 251 and the ring holder 252, a primer may be applied to the surface of the ring holder 252 in advance, and a primer treatment may be performed to remove oxides on the surface of the ring holder 252.

[0213] 40 to 42, the stator casing 20 has the same structure as the stator casing 20 according to the embodiment shown in Figures 35 to 39. More specifically, the motor pump MP includes a stator casing 20 that houses the stator 3 and is molded integrally with the stator 3 by resin molding, and a motor frame 221 that covers the outer peripheral surface of the stator casing 20 and is in contact with the stator 3.

[0214] 43 is a diagram showing another embodiment of the motor pump. In this embodiment, components that are the same as or equivalent to those in the above-described embodiment are given the same reference numerals, and redundant explanations will be omitted.

[0215] 43 , the motor pump MP is equipped with multiple impellers 1 including at least a first impeller 1A disposed on the suction port 21a side and a second impeller 1B disposed on the discharge port 22a side. In one embodiment, at least one more impeller 1 may be disposed between the first impeller 1A and the second impeller 1B. A rotor holder 200 that holds a rotor 2 is fixed to the first impeller 1A, and a stator 3 housed in a resin stator casing 20 is disposed radially outward of the rotor 2.

[0216] As shown in Figure 43, the rotor 2 housed in the rotor holder 200 is fixed to the first impeller 1A, so the rotational force of the rotor 2 acts on the first impeller 1A. The rotational force acting on the first impeller 1A is transmitted to the second impeller 1B through the communication shaft 270. In this way, the first impeller 1A receives all of the rotational force of the rotor 2, so the load acting on the first impeller 1A becomes large, and there is a risk of damage to the first impeller 1A.

[0217] Therefore, it is desirable that the first impeller 1A have a higher strength than the other impellers 1 (in this embodiment, the second impeller 1B). Furthermore, in order to achieve a high head for the motor pump MP according to this embodiment, it is desirable that the first impeller 1A have a high strength. In this way, it is desirable that the motor pump MP equipped with multiple impellers 1 has not only a compact structure but also a structure with high strength. With such a structure, the motor pump MP can operate stably.

[0218] Therefore, the motor pump MP according to this embodiment not only has a compact structure but also has a structure that allows stable operation. The structure of the motor pump MP will be described below with reference to the drawings.

[0219] The first impeller 1A is supported by a first bearing 5, and a communication shaft 270 is connected to the first impeller 1A. The second impeller 1B is connected to the communication shaft 270. The motor pump MP includes an intermediate casing 275 disposed between the first impeller 1A and the second impeller 1B, and a liner ring 276 is connected to the intermediate casing 275. The liner ring 276 is a ring member that suppresses backflow of the treated liquid sucked into the second impeller 1B.

[0220] 43, the intermediate casing 275 is formed as a separate member from the stator casing 20, but the intermediate casing 275 and the stator casing 20 may be formed as the same member. In this embodiment, the return vanes 30 fixed to the intermediate casing 275 also serve as guide vanes that guide the treated liquid discharged from the first impeller 1A to the second impeller 1B. The return vanes (and guide vanes) 30 can efficiently convert the flow velocity of the treated liquid generated by the centrifugal force of the first impeller 1A into pressure and guide it to the liquid inlet of the first impeller 1B.

[0221] The discharge casing 22 integrally configures the return blades 30 and the partition plate 245 fixed to the return blades 30. That is, the discharge casing 22, the return blades 30, and the partition plate 245 are integrally molded members. The discharge casing 22, the return blades 30, and the partition plate 245, which are integrally configured, may be integrally configured by resin molding. In one embodiment, the discharge casing 22, the return blades 30, and the partition plate 245 may be separate members. The return blades 30 fixed to the discharge casing 22 also perform the same function as the return blades 30 fixed to the intermediate casing 275.

[0222] Fig. 44 is a diagram showing another embodiment of the motor pump. In the embodiment shown in Fig. 43, the rotor holder 200 has a structure similar to that of the rotor holder 200 according to the embodiment shown in Fig. 35. As shown in Fig. 44, the rotor holder 200 may have a structure similar to that of the rotor holder 200 according to the embodiment shown in Fig. 40.

[0223] Figure 45 is an enlarged view of the first impeller and the second impeller. As shown in Figure 45, the boss portion 281 of the first impeller 1A is larger in size than the boss portion 282 of the second impeller 1B. The boss portion 281 is the portion that connects to the communication shaft 270 of the first impeller 1A, and the boss portion 282 is the portion that connects to the communication shaft 270 of the second impeller 1B.

[0224] In the embodiment shown in Figure 45, the length L1 of the boss portion 281 in the direction of the center line CL is longer than the length L2 of the boss portion 282 in the direction of the center line CL. As described above, the load acting on the first impeller 1A as the rotor 2 rotates is greater than the load acting on the second impeller 1B. According to this embodiment, the boss portion 281 of the first impeller 1A is larger in size than the boss portion 282 of the second impeller 1B, so the first impeller 1A can fully receive the rotational force of the rotor 2. As a result, the motor pump MP can prevent damage to the first impeller 1A.

[0225] As shown in Figure 45, the motor pump MP is provided with a sleeve 280 that creates a predetermined distance between the first impeller 1A and the second impeller 1B. The sleeve 280 is disposed between the first impeller 1A and the second impeller 1B. By disposing the sleeve 280, the operator can easily manage the distance between the first impeller 1A and the second impeller 1B.

[0226] Each of the first impeller 1A and the second impeller 1B has a power transmission structure (such as a key structure, a double chamfer structure, or a spline structure), and is connected to the communication shaft 270 by such a structure.

[0227] In this embodiment, the first impeller 1A and the second impeller 1B are each fixed to the communicating shaft 270 by a fastener (e.g., a nut) 273 fastened to the communicating shaft 270. A sleeve 280 is disposed between the first impeller 1A and the second impeller 1B, and a rotating-side bearing body 272 (described later) is disposed between the fastener 273 and the second impeller 1B.

[0228] Therefore, by tightening the fastener 273, the sleeve 280 is pressed against the first impeller 1A, and the rotation-side bearing 272 is pressed against the second impeller 1B. As a result, the first impeller 1A is sandwiched between the tip 270a of the communication shaft 270 and the sleeve 280, and the second impeller 1B is sandwiched between the sleeve 280 and the rotation-side bearing 272. In this way, the first impeller 1A and the second impeller 1B are firmly fixed to the communication shaft 270.

[0229] In this embodiment, the tip 270a of the communicating shaft 270 is disposed on the suction side, and the fastener 273 is disposed on the discharge side. In one embodiment, the tip 270a of the communicating shaft 270 may have a hexagonal head or a hexagonal socket. This structure allows the operator to firmly tighten the fastener 273 to the communicating shaft 270 while keeping the tip 270a fixed.

[0230] Figure 46 is a diagram showing another embodiment of the connection structure between the first impeller, the second impeller, and the communication shaft. As shown in Figure 46, the motor pump MP is provided with collets 285, 286 that fasten the first impeller 1A and the second impeller 1B to the communication shaft 270. Since the collets 285, 286 have the same structure, the structure of the collet 285 will be described below.

[0231] Collet 285 is a cylindrical member having a tapered shape and has a notch (not shown) extending in the direction of center line CL. By inserting collet 285 into first impeller 1A from the rear side of first impeller 1A, collet 285 bites into first impeller 1A, and first impeller 1A is fastened to communicating shaft 270. Similarly, by inserting collet 286 into second impeller 1B, collet 286 bites into second impeller 1B, and second impeller 1B is fastened to communicating shaft 270. With this structure, first impeller 1A and second impeller 1B are each fastened to communicating shaft 270 more firmly.

[0232] When the first impeller 1A is fastened to the communication shaft 270, a gap is formed between the tip of the collet 285 and the tip 270a of the communication shaft 270. When the second impeller 1B is fastened to the communication shaft 270, a gap is formed between the tip of the collet 286 and the sleeve 280.

[0233] 43 (and 44), the motor pump MP is provided with a second bearing (slide bearing) 277, which is arranged downstream of the second impeller 1B and rotatably supports the communicating shaft 270. The second bearing 277 is provided with a rotating-side bearing body 272 arranged on the communicating shaft 270 side, and a fixed-side bearing body 271 arranged on the discharge casing 22 side.

[0234] The rotating-side bearing 272 is a rotating-side cylindrical body attached to the communicating shaft 270, and the fixed-side bearing 271 is a fixed-side cylindrical body attached to the discharge casing 22 and surrounding the rotating-side bearing 272 as a rotating-side cylindrical body. The partition plate 245 of the discharge casing 22 has a bearing support portion 246 that supports the fixed-side bearing 271. The fixed-side bearing 271 is fixed to the bearing support portion 246. A small gap is formed between the fixed-side bearing 271 and the rotating-side bearing 272.

[0235] Ceramic or resin can be cited as an example of the material of the second bearing 277. When the communication shaft 270 rotates together with the rotation of the first impeller 1A, liquid enters between the fixed-side bearing body 271 and the rotating-side bearing body 272, and the fixed-side bearing body 271 supports the rotating-side bearing body 272 by the dynamic pressure of this liquid.

[0236] By providing the second bearing 277, the communicating shaft 270 is supported not only by the first bearing 5 fixed to the first impeller 1A, but also by the second bearing 277. The communicating shaft 270, to which multiple impellers 1 are connected, becomes longer in the direction of the center line CL. The motor pump MP equipped with the first bearing 5 and the second bearing 277 suppresses axial runout of the communicating shaft 270 that occurs when the communicating shaft 270 is longer, and as a result, can operate stably.

[0237] The assembly procedure for the motor pump MP will be described below. First, the first impeller 1A is fastened to the communicating shaft 270 (step 1). Next, the intermediate casing 275 (see FIGS. 43 and 44) ​​is inserted onto the communicating shaft 270 (step 2), and the sleeve 280 is inserted onto the communicating shaft 270 (step 3). Next, the second impeller 1B is inserted onto the communicating shaft 270, and the second impeller 1B and communicating shaft 270 are fastened together (step 4). Next, the rotating-side bearing body 272 is inserted onto the communicating shaft 270 (step 5), and the discharge casing 22 is fastened to the stator casing 20 (step 6). Next, the fastener 273 is fastened to the communicating shaft 270 (step 7).

[0238] In one embodiment, the operator may perform step 5, then step 7, and then step 6. However, as the number of impellers 1 fixed to the communicating shaft 270 increases, the communicating shaft 270 may tilt, and as a result, the position of the communicating shaft 270 may deviate from the direction of the center line CL.

[0239] Therefore, it is preferable that the worker attach the discharge casing 22 and check the positional relationship between the rotating-side bearing body 272 and the fixed-side bearing body 271 before fastening the fastener 273 to the communicating shaft 270. According to this embodiment, the motor pump MP is a straight-type motor pump in which the suction port 21 a and the discharge port 22 a are aligned, and therefore the fastener 273 can be fastened to the communicating shaft 270 while the communicating shaft 270 is supported by the second bearing 277.

[0240] FIG. 47 shows another embodiment of the fastener. As shown in FIG. 47 , the fastener 290 has a smaller diameter than the rotation-side bearing 272. In one embodiment, the fastener 290 may have the same diameter as the rotation-side bearing 272. A spacer 291 is disposed between the fastener 290 and the communication shaft 270. By inserting the fastener 290 into a threaded hole 270b formed at the end of the communication shaft 270, the spacer 291 presses the rotation-side bearing 272 against the second impeller 1B. According to this embodiment, even when the fixed-side bearing 271 is inserted, contact between the fastener 290 and the fixed-side bearing 271 is reliably prevented.

[0241] In this embodiment, by inserting the collets 285, 286 into the first impeller 1A and the second impeller 1B, respectively, the first impeller 1A and the second impeller 1B are sufficiently fastened to the communication shaft 270. Therefore, the fastener 290 only needs to have a fastening force sufficient to limit movement of the rotation-side bearing body 272 in the direction of the center line CL.

[0242] Figure 48 is a diagram showing another embodiment of the second bearing. As shown in Figure 48, the rotating-side bearing body 272 may be formed integrally with the communicating shaft 270. In this case, the communicating shaft 270 is made of the same bearing material (e.g., ceramic, steel, etc.) as the rotating-side bearing body 272. In the embodiment shown in Figure 48, a fixed-side bearing body 271 is arranged around the communicating shaft 270 which is formed integrally with the rotating-side bearing body 272.

[0243] Figure 49 is a diagram showing another embodiment of the second bearing. In the embodiment shown in Figure 49, the fixed-side bearing body 271 is formed integrally with the bearing support portion 246 of the discharge casing 22. In this embodiment, the bearing support portion 246 is made of the same bearing material (for example, ceramic, steel, or resin) as the fixed-side bearing body 271.

[0244] In this way, the motor pump MP may include a first impeller 1A having the same structure as the impeller 1 according to the embodiment shown in Figures 35 to 39, or may include a first impeller 1A having the same structure as the impeller 1 according to the embodiment shown in Figures 40 to 42. In one embodiment, the motor pump MP may include a first impeller 1A having the same structure as the impeller 1 according to the embodiment shown in Figures 1 to 34. In other words, the embodiments shown in Figures 1 to 49 may be combined to the extent possible.

[0245] Figure 50 is a diagram showing a side plate provided in the motor pump according to the embodiment described above. As shown in Figure 50, the motor pump MP may further include a side plate 300 that restricts the outflow of the liquid (handled liquid) pressurized by the impeller 1 into the discharge casing 22. In the embodiment shown in Figure 50, the side plate 300 has a disk shape and is fixed to the return vanes 30.

[0246] The side plate 300 is disposed between the main plate 10 and the return blades 30 of the impeller 1. A portion of the liquid pressurized by the impeller 1 passes through the return blades 30 and the gap between the side plate 300 and the discharge casing 22, and is discharged from the discharge port 22a. The other portion of the liquid pressurized by the impeller 1 flows into the gap between the side plate 300 and the main plate 10 of the impeller 1.

[0247] When the impeller 1 rotates, the force of the liquid (i.e., fluid force) acts on the impeller 1, pushing the impeller 1 toward the discharge casing 22. The flow of liquid that has flowed into the gap between the side plate 300 and the main plate 10 is restricted by the side plate 300, so the pressurized liquid remains in the gap between the side plate 300 and the main plate 10. The liquid remaining in the gap between the side plate 300 and the main plate 10 receives the fluid force acting on the impeller 1, so movement of the impeller 1 toward the discharge casing 22 is restricted.

[0248] When the motor pump MP is operated steadily, a thrust force acts on the impeller 1 from the discharge casing 22 side toward the suction casing 21 side. Therefore, even if a fluid force acts on the impeller 1, the impeller 1 is stably held by the bearing 5. In the embodiment shown in Figure 50, an embodiment in which the side plate 300 is applied to the motor pump MP according to the embodiment shown in Figure 1 has been described, but the side plate 300 can also be applied to the motor pumps MP according to the embodiments shown in Figures 2 to 49.

[0249] Fig. 51 shows another embodiment of the side plate. As shown in Fig. 51, the side plate 300 may have an opening 300a formed in the center thereof. As described above, liquid that has flowed into the gap between the side plate 300 and the main plate 10 may remain in the gap between the side plate 300 and the main plate 10.

[0250] In this case, the rotation of the impeller 1 causes the stagnant liquid to swirl and eventually generate heat. By forming the opening 300a in the side plate 300, a circulating flow of liquid is created between the gap between the side plate 300 and the discharge casing 22 and the gap between the side plate 300 and the impeller 1. Therefore, the liquid present between the side plate 300 and the impeller 1 flows toward the discharge casing 22, preventing the liquid from generating heat and maintaining a constant temperature of the liquid. Furthermore, the opening 300a can serve to discharge air contained in the stagnant liquid toward the discharge casing 22.

[0251] 51, the opening 300a of the side plate 300 is a single opening formed on the center line CL, but the number of openings 300a is not limited to this embodiment. The side plate 300 may have multiple openings 300a as long as they limit the movement of the impeller 1 toward the discharge casing 22.

[0252] Furthermore, the opening 300 a does not necessarily have to be formed on the center line CL as long as it can form a circulating flow of the liquid. For example, the side plate 300 may have at least one opening 300 a arranged concentrically around the center line CL.

[0253] The shape of the opening 300a is not particularly limited, and may be circular or polygonal (e.g., triangular or rectangular). The size (i.e., area) of the opening 300a is also not particularly limited, as long as it limits the movement of the side plate 300 toward the discharge casing 22.

[0254] Figure 52 is a diagram showing another embodiment of the motor pump. In the embodiment shown in Figure 52, the motor pump MP includes a discharge casing 22 having a discharge port 322 extending in a vertical direction perpendicular to the center line CL of the motor pump MP. The discharge port 322 has a discharge opening 322a that opens upward, and the suction opening 21a and the discharge opening 322a are perpendicular to each other.

[0255] In the embodiment shown in Figure 52, the motor pump MP is a so-called end-top type motor pump in which the suction port 21a and the discharge port 322a are perpendicular to each other. This type of motor pump MP has a compact structure. For example, depending on the installation environment of the motor pump MP, it may not be possible to install a motor pump MP having a structure in which the suction port 21a and the discharge port 22a are aligned in a straight line. Even in such cases, an end-top type motor pump MP can be installed. In this way, in this embodiment, the motor pump MP can be installed in any installation environment.

[0256] As shown in Figure 52, the motor pump MP may further include a side plate 300 that restricts the outflow of the liquid (handled liquid) pressurized by the impeller 1 to the discharge port 322. In this manner, the side plate 300 is also applicable to an end-top type motor pump MP. Note that in the embodiment shown in Figure 52, the side plate 300 may also have an opening 300a (see Figure 51).

[0257] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would naturally be possible for a person skilled in the art, and the technical concept of the present invention may also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims.

[0258] The present invention can be used in a motor pump.

[0259] DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C Impeller 2 Rotor 2a Iron core 2b Magnet 3 Stator 3a Stator core 3b Coil 5 Bearing 6 Rotating-side bearing body 6a Cylindrical portion 6b Flange portion 7 Fixed-side bearing body 7a Cylindrical portion 7b Flange portion 10 Main plate 10a Through hole 11 Side plate 11a Outer edge portion 12 Blade 15 Suction portion 16 Main body portion 17 Projection portion 17a Outer peripheral surface 17b Inner peripheral surface 20 Stator casing 20a Inner peripheral surface 21 Suction casing 21a Suction port 22 Discharge casing 22a Discharge port 25 Through bolt 25a Head portion 30 Return vane 31 Seal member 32, 33 Seal members 40, 41, 42 Groove 41a Both ends 45 Load reduction structure 46 Rear blade 47 Notch 50, 51 Inclined surface 53, 54 Inclined surface 60 Inverter 61 Intermediate casing 65 Pipe 70, 70A,70B Convex portion 71 Tip portion 75 Balance adjustment jig (center support adjustment jig) 76 Shaft body 77 Fixture 80 Center cap 85 Balance adjustment jig (edge ​​support adjustment jig) 86 Supporter 87 Shaft portion 90 Weight insertion hole 91 Weight 100 Control device 100a Signal receiving unit 100b Memory unit 100c Control unit 101 Current sensor 102 Terminal block 105 Power line 106 Signal line 107 Protective cover 108 Copper bar 110 Cover 117 Protrusion 118 Mounting portion 120 Seal member 121 Seal member 125 Intermediate casing 126 Connecting shaft 127A Seal member 127B Seal member 128 Discharge side bearing 129 Flow path 130 Swivel stopper 140 Connecting pipe 141 Suction casing 141a Suction port 141b Insertion hole 142 Discharge casing 142a Discharge port 142b Bolt accommodating portion 150 Fastener 160 Main plate 200 Rotor holder 201 Accommodating portion 201a Outer surface 201b Inner surface 201c Corner surface 202 Closure plate 203 Spacer 205 Seal member 220 Insulating material 221 Motor frame 229 Seal groove 230 Inner surface 231 Outer annular portion 232 Inner annular portion 233 Back surface portion 235 Protrusion 240 Partition plate 241 Seal member 242 Pass-through hole 245 Partition plate 251 Accommodating portion 252 Ring holder 253 Ring portion 253a Embedded hole 253b Bent portion 254 Bent portion 254a Embedded hole 254b Bent portion 255 Main body portion 256 Bent portion 260 Spacer 270 Communicating shaft 270a Tip portion 270b Screw hole 271 Fixed side bearing body 272 Rotating side bearing body 273 Fastener 275 Intermediate casing 276 Liner ring 277 Second bearing 280 Sleeve 281 Boss portion 282 Boss portion 285,286 Collet 290 Fastener 291 Spacer 300 Side plate 300a Opening 322 Discharge port 322a Discharge port MP Motor pump PU Pump unit CL Center line Ra Suction side area Rb Discharge side area Rc Intermediate area RS Rotating shaft Nt Nut

Claims

1. A first impeller, a rotor fixed to the first impeller, a stator disposed radially outside the rotor, a first bearing that supports the first impeller and is disposed outside the flow path of the first impeller, a communication shaft connected to the first impeller, a second impeller connected to the communication shaft, and a motor pump in which the boss portion of the first impeller has a size larger than that of the boss portion of the second impeller.

2. The motor pump includes a sleeve that forms a predetermined distance between the first impeller and the second impeller, and the sleeve is disposed between the first impeller and the second impeller. The motor pump according to claim 1.

3. The motor pump according to claim 1 includes collets that fasten the first impeller and the second impeller to the communication shaft respectively.

4. A first impeller, a rotor fixed to the first impeller, a stator disposed radially outside the rotor, a first bearing that supports the first impeller and is disposed outside the flow path of the first impeller, a communication shaft connected to the first impeller, a second impeller connected to the communication shaft, and a second bearing that supports the communication shaft and is disposed downstream of the second impeller. A motor pump comprising.

5. The motor pump includes a discharge casing disposed on the downstream side of the second impeller, and the second bearing includes a rotating-side bearing body disposed on the communication shaft side, and a fixed-side bearing body disposed on the discharge casing side. The motor pump according to claim 4.

6. The rotating-side bearing body is a rotating-side cylindrical body mounted on the communication shaft, and the fixed-side bearing body is a fixed-side cylindrical body attached to the discharge casing and surrounding the rotating-side cylindrical body. The motor pump according to claim 5.

7. The rotating-side bearing body is integrally formed with the communication shaft, and the fixed-side bearing body is integrally formed with the discharge casing. The motor pump according to claim 6.

8. The motor pump includes a rotor holder that holds the rotor, and the first impeller is a press-formed product to which the rotor holder is fixed. The motor pump according to claim 1 or 4.

9. The rotor holder includes a press-formed annular accommodating portion that accommodates the rotor, The motor pump according to claim 8, further comprising an annular closing plate for closing the accommodating portion.

10. The motor pump includes a rotor holder for holding the rotor, The motor pump according to claim 1 or 4, wherein the first impeller is a resin molded product integrally formed with the rotor holder.

11. The rotor holder, A resin-molded annular accommodating portion for accommodating the rotor, and A ring holder for closing the accommodating portion, the motor pump according to claim 10.

12. The motor pump according to claim 11, wherein the ring holder has a rotation prevention structure formed at a connection portion with the accommodating portion.

13. The motor pump according to claim 12, wherein the rotation prevention structure is an embedding hole in which a part of the accommodating portion is embedded.

14. The motor pump according to claim 12, wherein the rotation prevention structure is a bent portion bent in a U shape.

15. The first bearing, A rotating side bearing body attached to the rotor holder, and A fixed side bearing body disposed on the suction side of the rotating side bearing body, the motor pump according to claim 8.

16. The motor pump according to claim 1 or 4, further comprising a stator casing that houses the stator and is integrally resin-molded with the stator.

17. The motor pump according to claim 16, further comprising a motor frame that covers an outer peripheral surface of the stator casing and contacts the stator.

18. The motor pump according to claim 1 or 4, wherein the rotor and the first bearing are disposed in a suction side region of the impeller.