motor pump

Abstract

To provide a fixed side bearing structure that can improve pump efficiency at low cost.SOLUTION: A fixed side bearing structure 12 comprises a fixed side bearing body 40, and a blocking body 41 having a size capable of blocking a circulation flow passage R2 of a motor can 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fixed-side bearing structure and a motor pump. [Background technology]

[0002] Canned motor pumps, in which the motor and pump are integrated, do not require a shaft seal to seal the gap between the rotating shaft and the pump casing, so liquid leakage does not occur. Therefore, canned motor pumps are widely used in fields where liquid leakage is unacceptable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-13040 A [Patent Document 2] Japanese Patent Application Publication No. 2017-180754 [Patent Document 3] Japanese Patent Application Publication No. 5-187386 Summary of the Invention [Problem to be solved by the invention]

[0004] Such motor pumps may have a liquid circulation flow path extending from the liquid outlet to the liquid inlet of the impeller to cool the motor. However, when the liquid being handled is at a low temperature, even though cooling of the motor is not necessary, forming the liquid circulation flow path causes some of the liquid discharged from the impeller to return to the liquid inlet of the impeller. As a result, the pumping efficiency of the motor pump decreases.

[0005] In order to construct a motor pump without a liquid circulation flow path, it is possible to consider modifying the entire structure of the motor pump, but such structural modifications would be extremely costly.

[0006] Therefore, the present invention can improve pump efficiency at low cost. Rumo The object of the present invention is to provide a motor pump. [Means for solving the problem]

[0007] In one aspect, a fixed side bearing structure is provided, comprising a fixed side bearing body that can be positioned radially inward of a rotating side bearing, and a blocking body that is sized to block the circulation flow path of a motor can that is positioned opposite the fixed side bearing body.

[0008] In one aspect, the fixed side bearing body has a non-blocking portion arranged opposite the circulation flow path, and the blocking body has a blocking protrusion fixed to the fixed side bearing body and arranged between adjacent non-blocking portions. In one aspect, the fixed side bearing structure is configured to switch, by rotation, between an open state in which the non-blocking portion faces the circulation flow path to open the circulation flow path, and a closed state in which the blocking protrusion faces the circulation flow path to block the circulation flow path. In one embodiment, the number of the blocking protrusions corresponds to the number of the circulation channels.

[0009] In one aspect, the closure comprises an annular projection having an annular shape. In one embodiment, the blocking body includes a blocking ring that is a separate member from the fixed-side bearing body.

[0010] In one aspect, there is provided a motor pump including an impeller housing a permanent magnet, a pump casing housing the impeller, a bearing assembly supporting the impeller, and a motor casing housing a motor stator, wherein the bearing assembly includes the fixed-side bearing structure and a rotating-side bearing disposed around the fixed-side bearing structure, and the motor casing includes a motor can having a circulation flow path disposed opposite the fixed-side bearing structure. [Effects of the Invention]

[0011] The fixed-side bearing structure includes a blocking body that blocks the circulation flow path of the motor can. A fixed-side bearing structure having such a structure can improve pump efficiency with a simple structure that only includes a blocking body, and can also contribute to cost reduction. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing an embodiment of a motor pump in which a motor and a pump are integrally configured. FIG. [Figure 2] FIG. 10 is a diagram showing a circulation flow path formed in a motor can. [Figure 3] FIG. 3(a) is a diagram showing the fixed-side bearing structure, and FIG. 3(b) is a diagram of FIG. 3(a) viewed from the direction of line A. [Figure 4] FIG. 10 is a diagram showing a circulation flow path blocked by a blocking protrusion. [Figure 5] FIG. 10 shows a circulation flow path opened by an unoccluded area. [Figure 6] FIG. 6(a) is a diagram showing another embodiment of the fixed-side bearing structure, and FIG. 6(b) is a view of FIG. 6(a) as seen from the direction of line B. [Figure 7] 10A and 10B are diagrams showing another embodiment of the fixed-side bearing structure. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, identical or corresponding components are designated by the same reference numerals, and duplicated descriptions will be omitted. In the multiple embodiments described below, the configuration of an embodiment that is not particularly described is the same as that of other embodiments, and therefore duplicated descriptions will be omitted.

[0014] Figure 1 shows an embodiment of a motor pump in which the motor and pump are integrated. As shown in Figure 1, the motor pump MP is a canned motor pump equipped with an axial gap type PM motor. The motor pump MP includes an impeller 1 in which a plurality of permanent magnets 5 are embedded, a motor stator 6 that generates a magnetic force that acts on these permanent magnets 5, a pump casing 2 that houses the impeller 1, a motor casing 3 that houses the motor stator 6, and a bearing assembly 10 that supports the radial load and thrust load of the impeller 1.

[0015] The motor stator 6 and bearing assembly 10 are disposed on the suction side of the impeller 1. In this embodiment, multiple permanent magnets 5 are provided, but the present invention is not limited to this embodiment, and a single permanent magnet having multiple magnetized poles may also be used. More specifically, a single annular permanent magnet having multiple magnetic poles, in which south and north poles are alternately magnetized, may also be used.

[0016] The motor pump MP is provided with an O-ring 9 as a sealing member disposed between the pump casing 2 and the motor casing 3. The O-ring 9 can prevent liquid from leaking from between the pump casing 2 and the motor casing 3.

[0017] The motor casing 3 includes a motor can 30 that houses the motor stator 6, and a suction port 15 that has a suction opening 15a and is connected to the motor can 30. The suction port 15 has a flange shape and is connected to a suction line (not shown).

[0018] The motor pump MP has a suction port 15, a motor can 30, and a liquid flow path R1 formed in the center of the bearing assembly 10. The liquid flow path R1 extends along the center line CL of the motor pump MP from the suction port 15a to the liquid inlet of the impeller 1, and is connected to the liquid inlet of the impeller 1. The motor pump MP is a canned motor pump equipped with an axial gap type PM motor in which the permanent magnets 5 and the motor stator 6 are arranged along the liquid flow path R1.

[0019] The pump casing 2 has a discharge port 16 formed on its side surface, the discharge port 16 having a discharge port 16a. The liquid pressurized by the rotating impeller 1 is discharged through the discharge port 16a. The motor pump MP according to the embodiment shown in Fig. 1 is a so-called end-top type motor pump, in which the suction port 15a and the discharge port 16a intersect at right angles.

[0020] The impeller 1 is made of a non-magnetic material that is slippery and resistant to wear. For example, resins such as PTFE (polytetrafluoroethylene) and PPS (polyphenylene sulfide), or ceramics are preferably used. The pump casing 2 and motor casing 3 may be made of the same material as the impeller 1.

[0021] The motor stator 6 has a stator core 6A and multiple stator coils 6B. These multiple stator coils 6B are arranged in a ring shape. The impeller 1 and the motor stator 6 are arranged concentrically with the bearing assembly 10 and the suction port 15a.

[0022] The motor pump MP is equipped with an inverter device (control board) 21 that supplies current to the motor stator 6. The stator coil 6B is connected to the inverter device 21 via lead wires 25. The inverter device 21 is housed in a motor can 30, and the open end of the motor can 30 is closed by a closing member 20.

[0023] The inverter device 21 supplies current to the stator coil 6B of the motor stator 6, generating a rotating magnetic field in the motor stator 6. This rotating magnetic field acts on the permanent magnets 5 embedded in the impeller 1, driving it to rotate. As the impeller 1 rotates, liquid is introduced into the liquid inlet of the impeller 1 from the suction port 15a. The liquid is pressurized by the rotation of the impeller 1 and is discharged from the discharge port 16a. While the impeller 1 is transporting the liquid, the back surface of the impeller 1 is pressed against the suction side (i.e., toward the suction port 15a) by the pressurized liquid. The bearing assembly 10 is disposed on the suction side of the impeller 1, and therefore supports the thrust load of the impeller 1 from the suction side.

[0024] The impeller 1 is rotatably supported by a single bearing assembly 10. The bearing assembly 10 is a sliding bearing (hydrodynamic bearing) that utilizes the dynamic pressure of a liquid. The bearing assembly 10 includes a fixed-side bearing structure 12 and a rotating-side bearing 11 that is arranged around the fixed-side bearing structure 12. In other words, the fixed-side bearing structure 12 is arranged radially inward of the rotating-side bearing 11.

[0025] The fixed-side bearing structure 12 has a cylindrical fixed-side radial surface 12a and a fixed-side thrust surface 12b located radially outward of the fixed-side radial surface 12a. The rotating-side bearing 11 has a cylindrical rotating-side radial surface 11a surrounding the fixed-side radial surface 12a and a rotating-side thrust surface 11b located radially outward of the rotating-side radial surface 11a.

[0026] The rotating-side bearing 11 is fixed to the impeller 1 by an O-ring 18 serving as a sealing member, and is arranged to surround the liquid inlet of the impeller 1. The fixed-side bearing structure 12 is fixed to the motor can 30, and is arranged on the suction side of the rotating-side bearing 11. The motor pump MP is provided with an O-ring 31 serving as a sealing member, which is arranged between the motor can 30 and the fixed-side bearing structure 12.

[0027] The rotating-side radial surface 11a and the fixed-side radial surface 12a are radial surfaces that support the radial load of the impeller 1, and the rotating-side thrust surface 11b and the fixed-side thrust surface 12b are thrust surfaces that support the thrust load of the impeller 1. The rotating-side radial surface 11a and the fixed-side radial surface 12a are parallel to the axis of the impeller 1 (i.e., the direction of the axis line CL), and the rotating-side thrust surface 11b and the fixed-side thrust surface 12b are perpendicular to the axis of the impeller 1. The rotating-side radial surface 11a and the rotating-side thrust surface 11b are perpendicular to each other, and the fixed-side radial surface 12a and the fixed-side thrust surface 12b are perpendicular to each other.

[0028] A portion of the liquid discharged from the impeller 1 is guided to the bearing assembly 10 through the minute gap between the impeller 1 and the motor can 30. When the rotating-side bearing 11 rotates together with the impeller 1, dynamic pressure of the liquid is generated between the rotating-side bearing 11 and the fixed-side bearing structure 12, and as a result, the impeller 1 is supported by the bearing assembly 10 without contact.

[0029] Fig. 2 is a diagram showing the circulation flow path formed in the motor can. As shown in Fig. 1 and Fig. 2, the motor can 30 has a circulation flow path R2 arranged opposite the fixed-side bearing structure 12. The circulation flow path R2 is formed on the opposing surface 30a of the motor can 30 that faces the fixed-side bearing structure 12.

[0030] 2, the motor can 30 has three circulation channels R2 arranged at equal intervals along its inner circumferential surface, but the number of circulation channels R2 is not limited to this embodiment. In one embodiment, at least one circulation channel R2 may be formed.

[0031] A portion of the liquid discharged from the impeller 1 passes through the circulation flow path R2 and is returned to the liquid flow path R1. The liquid flowing through the circulation flow path R2 can cool the stator coil 6B, which serves as a heating element. However, if the liquid transported by the motor pump MP is at a low temperature (for example, a liquid below 0°C), cooling of the stator coil 6B is not necessary. Nevertheless, a portion of the liquid discharged from the impeller 1 passes through the circulation flow path R2 and is returned to the liquid inlet of the impeller 1. This reduces the pumping efficiency of the motor pump MP.

[0032] Therefore, the fixed-side bearing structure 12 has a structure that blocks the circulation flow path R2 to prevent the liquid from flowing back into the liquid flow path R1. The structure of the fixed-side bearing structure 12 will be described below with reference to the drawings.

[0033] Fig. 3(a) is a diagram showing the fixed-side bearing structure, and Fig. 3(b) is a diagram of Fig. 3(a) as seen from the direction of line A. The fixed-side bearing structure 12 comprises a fixed-side bearing body 40 that can be arranged radially inside the rotating-side bearing 11, and a blocking body 41 that is arranged opposite the fixed-side bearing body 40 and has a size that can block the circulation flow path R2 of the motor can 30.

[0034] The fixed-side bearing body 40 has an overall cylindrical shape, and the fixed-side radial surface 12a and the fixed-side thrust surface 12b are formed on the fixed-side bearing body 40. The blocking body 41 has a plurality of blocking protrusions 42 fixed to the fixed-side bearing body 40.

[0035] In this embodiment, three blocking protrusions 42 are formed, but the number of blocking protrusions 42 is not limited to this embodiment. The number of blocking protrusions 42 corresponds to the number of circulation flow paths R2. Therefore, for example, when one circulation flow path R2 is formed, the blocking body 41 has a single blocking protrusion 42.

[0036] The fixed-side bearing body 40 has a non-blocking portion 40a arranged opposite the circulation flow path R2. The non-blocking portion 40a is an opposing surface of the fixed-side bearing body 40 that faces the opposing surface 30a of the motor can 30 when the fixed-side bearing structure 12 is attached to the motor can 30.

[0037] The blocking protrusions 42 are fixed to the non-blocking portions (i.e., opposing surfaces) 40a of the fixed-side bearing body 40, and are arranged at equal intervals along the circumferential direction of the fixed-side bearing body 40. Each of the multiple blocking protrusions 42 is arranged between adjacent non-blocking portions 40a. In other words, the multiple blocking protrusions 42 and the non-blocking portions 40a are arranged alternately along the circumferential direction of the fixed-side bearing body 40.

[0038] Fig. 4 is a diagram showing the circulation flow path blocked by the blocking protrusion. Fig. 5 is a diagram showing the circulation flow path opened by the non-blocking portion. As shown in Figs. 4 and 5, the fixed-side bearing structure 12 is configured to switch, by rotation, between an open state (see Fig. 5) in which the non-blocking portion 40a faces the circulation flow path R2 to open the circulation flow path R2, and a closed state (see Fig. 4) in which the blocking protrusion 42 faces the circulation flow path R2 to block the circulation flow path R2.

[0039] When the liquid handled by the motor pump MP is at a low temperature, it is desirable to block the circulation flow path R2 to improve the pump efficiency. In this case, as shown in FIG. 4, the operator attaches the fixed-side bearing structure 12 to the motor can 30 so that the blocking protrusion 42 fits into the circulation flow path R2. Therefore, the blocking protrusion 42 blocks the circulation flow path R2 and prevents the liquid from flowing back into the liquid flow path R1. As a result, the pump efficiency of the motor pump MP can be improved.

[0040] According to this embodiment, the pump efficiency can be improved with a simple structure that simply requires forming the blocking body 41 on the fixed-side bearing body 40. Furthermore, according to this embodiment, there is no need to modify the overall structure of the motor pump MP, and the pump efficiency can be improved at low cost by simply applying the fixed-side bearing structure 12 to the motor pump MP.

[0041] A mark S (see FIGS. 3(a) and 4) is formed on the fixed-side thrust surface 12b of the fixed-side bearing body 40, which faces the blocking protrusion 42. Therefore, an operator can fit the blocking protrusion 42 into the circulation flow path R2 without visually checking the blocking protrusion 42.

[0042] When the liquid in the motor pump MP is hot, it is desirable to open the circulation flow path R2 and return the liquid to the liquid flow path R1. Because the temperature of the stator coil 6B is higher than that of the liquid, the liquid can absorb heat from the stator coil 6B. In this case, as shown in FIG. 5, the operator rotates the fixed-side bearing body 40 so that the non-blocking portion 40a faces the circulation flow path R2. As a result, the non-blocking portion 40a faces the opposing surface 30a of the motor can 30.

[0043] As described above, the O-ring 31 is disposed between the motor can 30 and the fixed-side bearing structure 12. Therefore, in one embodiment, after removing the fixed-side bearing structure 12 from the motor can 30, the worker may rotate the fixed-side bearing structure 12 by a predetermined angle.

[0044] In the above-described embodiment, the fixed side bearing structure 12 has a blocking protrusion 42 fixed to the fixed side bearing body 40, but in one embodiment, the blocking protrusion 42 may be a separate member from the fixed side bearing body 40.

[0045] FIG. 6(a) is a diagram showing another embodiment of the fixed-side bearing structure, and FIG. 6(b) is a view of FIG. 6(a) as viewed from the direction of line B. As shown in FIGS. 6(a) and 6(b), the blocking body 41 may include an annular protrusion 43 having an annular shape. The annular protrusion 43 is arranged concentrically with the impeller 1 and the suction port 15a. According to this embodiment, by attaching the fixed-side bearing structure 12 to the motor can 30, the annular protrusion 43 can block all of the circulation flow paths R2, regardless of the number of circulation flow paths R2.

[0046] In this embodiment, when the liquid handled by the motor pump MP is hot, an operator can remove the fixed-side bearing structure 12 and instead attach a fixed-side bearing body 40 without a blocking body 41 to the motor can 30, thereby opening the circulation flow path R2. As a result, the handled liquid can remove heat from the stator coil 6B.

[0047] Fig. 7 is a diagram showing another embodiment of the fixed-side bearing structure. As shown in Fig. 7, the blocking body 41 includes a blocking ring 44 that is a separate member from the fixed-side bearing body 40. The worker mounts the fixed-side bearing structure 12 to the motor can 30 with the blocking ring 44 positioned between the non-blocking portion 40a of the fixed-side bearing body 40 and the opposing surface 30a of the motor can 30. Mounting in this manner allows the blocking ring 44 to block the circulation flow path R2. In this embodiment, too, the blocking ring 44 can block all of the circulation flow paths R2, regardless of the number of circulation flow paths R2.

[0048] In this embodiment, when the temperature of the liquid handled by the motor pump MP is high, an operator can open the circulation flow path R2 by removing the blocking ring 44 and attaching the fixed-side bearing body 40 to the motor can 30. As a result, the handled liquid can remove heat from the stator coil 6B.

[0049] 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 be obvious to a person skilled in the art, and the technical concept of the present invention may 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. [Explanation of symbols]

[0050] 1 impeller 2 Pump casing 3 Motor casing 5. Permanent magnets 6 Motor stator 6A stator core 6B Stator coil 9 O-ring 10 Bearing assembly 11 Rotating side bearing 11a Rotating side radial surface 11b Rotating side thrust surface 12 Fixed side bearing structure 12a Fixed side radial surface 12b Fixed side thrust surface 15 Suction port 15a Intake port 16 Discharge port 16a Discharge port 18 O-ring 20 Closing member 21 Inverter device (control board) 25 lead wire 30 Motor can 30a Opposite side 31 O-ring 40 Fixed side bearing body 40a Unoccluded area 41 Obstruction body 42 Obstruction process 43 Annular protrusion 44 Occlusion Ring MP motor pump R1 Liquid flow path R2 Circulation channel S landmark

Claims

1. A motor pump, an impeller containing a permanent magnet; a pump casing that houses the impeller; a bearing assembly that supports the impeller and includes a fixed-side bearing structure; a motor casing that houses a motor stator; The fixed-side bearing structure is a fixed-side bearing body that can be disposed radially inside the rotating-side bearing; a closing body having a size capable of closing the circulation flow path of the motor can arranged opposite the fixed side bearing body.

2. the fixed-side bearing body has a non-blocking portion disposed opposite the circulation flow path, 2. The motor pump according to claim 1, wherein the obstructing body includes an obstructing protrusion fixed to the fixed-side bearing body and disposed between the adjacent non-obstructing portions.

3. 3. The motor pump according to claim 2, wherein the fixed-side bearing structure is configured to rotate to switch between an open state in which the non-obstructing portion faces the circulation flow path to open the circulation flow path, and a closed state in which the obstructing protrusion faces the circulation flow path to block the circulation flow path.

4. 4. The motor pump according to claim 2, wherein the number of the blocking projections corresponds to the number of the circulation flow paths.

5. The motor pump according to claim 1 , wherein the closure comprises an annular protrusion having an annular shape.

6. 2. The motor pump according to claim 1, wherein the blocking body comprises a blocking ring which is a separate member from the fixed-side bearing body.

7. A motor pump, an impeller containing a permanent magnet; a pump casing that houses the impeller; a bearing assembly supporting the impeller; a motor casing that houses a motor stator; The bearing assembly includes: A fixed-side bearing structure according to any one of claims 1 to 6, a rotating-side bearing disposed around the fixed-side bearing structure, The motor pump includes a motor casing having a motor can having a circulation flow path arranged opposite the fixed-side bearing structure.

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