Canned motor pump

Abstract

To provide a canned motor pump capable of efficiently forming a circulation flow of a motor part by liquid.SOLUTION: A canned motor pump 1 includes a rotating shaft 5. The rotating shaft 5 has an axial direction communication hole 5a extending in the axial direction of the rotating shaft 5, and a radial direction communication hole 50 connected to the axial direction communication hole 5a. The radial direction communication hole 50 communicates with an impeller chamber 41.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A canned motor pump has a structure in which the motor is cooled by a liquid circulating inside the canned motor pump (for example, see Patent Document 1). A part of the liquid sucked into the canned motor pump is introduced into the motor section. The liquid introduced into the motor section circulates inside the motor section, thereby cooling the motor and lubricating the sliding bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 059709 [Patent Document 2] JP 2020-139458 A Summary of the Invention [Problem to be solved by the invention]

[0004] The temperature of the liquid introduced into the motor section rises due to heat generated by the rotor churning loss, can loss, rotor eddy current loss, etc., as well as heat generated by the stator windings, etc. Therefore, if the liquid circulation flow in the motor section is not properly formed, poor lubrication of the bearings will occur, and as a result, the bearings may wear out and be damaged.

[0005] In order to suppress the temperature rise of the liquid in the motor section, it is important to actively form a circulating flow of the liquid. In particular, it is important to form a circulating flow of the liquid that circulates throughout the entire motor section. For example, such a circulating flow of the liquid is a flow in which the liquid is first introduced into a narrow space between the rotor and the stator, and then returned to the impeller chamber through a through hole formed in the rotating shaft.

[0006] However, the liquid flowing into the narrow space may be repelled by the rotating rotor, and may not be able to pass through the narrow space smoothly. Furthermore, the circulation flow of the liquid that circulates through the entire motor section has a long flow path. Therefore, the circulation flow of the liquid may not be formed properly.

[0007] One possible solution to this problem is to reduce the rotational speed of the rotor, which reduces the centrifugal force acting on the liquid and suppresses heat generation caused by rotor agitation loss, can loss, etc.

[0008] However, in order to reduce the rotational speed of the rotor, a large canned motor pump must be adopted, making it difficult to miniaturize the canned motor pump. In particular, pump devices used for temperature control in semiconductor manufacturing equipment and other devices are required to have a small water volume, high head, and be as compact as possible.

[0009] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a canned motor pump that can efficiently form a circulating flow of liquid in the motor section. [Means for solving the problem]

[0010] In one aspect, there is provided a canned motor pump including a rotating shaft, an impeller attached to the rotating shaft, a pump casing having an impeller chamber arranged on a tip side of the rotating shaft, and a motor that rotates the rotating shaft. The rotating shaft has an axial communicating hole extending in the axial direction of the rotating shaft and a radial communicating hole connected to the axial communicating hole, and the radial communicating hole communicates with the impeller chamber.

[0011] In one embodiment, when the radial communicating hole is defined as a first radial communicating hole, the rotating shaft has a second radial communicating hole arranged on the opposite side of the first radial communicating hole with respect to its center. In one embodiment, the impeller has liquid outlet holes connected to the radial communication holes. In one embodiment, when the liquid outlet hole is defined as a first liquid outlet hole, the impeller has a second liquid outlet hole disposed on the opposite side of the first liquid outlet hole with respect to its center.

[0012] In one aspect, the impeller has a boss portion connected to the rotating shaft and a main plate portion extending outward from the boss portion, and the liquid outflow hole is formed in the boss portion. In one embodiment, the liquid outlet hole is disposed closer to the tip end of the rotating shaft than the main plate portion. In one embodiment, the canned motor pump is a vortex type canned motor pump having a vortex chamber surrounding a plurality of radial grooves formed on the periphery of the impeller.

[0013] In one aspect, the motor includes a rotor having a permanent magnet and a stator surrounding the rotor. In one aspect, the canned motor pump comprises a rotor can covering the rotor and a stator can arranged between the rotor and the stator, and at least one of the rotor can and the stator can is made of a non-magnetic material. Effect of the Invention

[0014] The rotating shaft has a radial communication hole that communicates with the impeller chamber. Therefore, when the rotating shaft is rotated by the drive of the motor, the liquid introduced into the motor section is actively returned to the impeller chamber through the radial communication hole by the pumping action. As a result, the canned motor pump can efficiently form a circulating flow of liquid in the motor section. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 illustrates an embodiment of a pump device. [Diagram 2] FIG. 2(a) is a diagram showing the suction port and discharge port of the pump device, and FIG. 2(b) is a diagram seen from the direction of arrow A in FIG. 2(a). [Diagram 3]FIG. 2 is a diagram showing a plurality of radial grooves formed on the impeller. [Figure 4] FIG. 13 is a diagram showing liquid flowing through axial communicating holes and radial communicating holes. [Diagram 5] 13A and 13B are views showing another embodiment of a radial communication hole. [Figure 6] FIG. 13 illustrates another embodiment of the pump device. [Figure 7] 7 is a view of the impeller in the pump shown in FIG. 6, as viewed from the pump casing side. [Figure 8] FIG. 7 is a view of the impeller in the pump shown in FIG. 6, as viewed from the bracket side. [Figure 9] FIG. 13 illustrates another embodiment of the pump device. [Figure 10] FIG. 13 illustrates another embodiment of the pump device. [Figure 11] FIG. 13 illustrates another embodiment of the pump device. [Figure 12] FIG. 12 is a diagram showing an impeller in the pump device shown in FIGS. 10 and 11. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings described below, the same or corresponding components are denoted by the same reference numerals, and duplicated descriptions will be omitted. In the multiple embodiments described below, the configuration of one embodiment that is not particularly described is the same as the other embodiments, so duplicated descriptions will be omitted.

[0017] Fig. 1 is a diagram showing one embodiment of a pump device. In the embodiment shown in Fig. 1, the pump device 1 includes a canned motor pump. The pump device 1 as a canned motor pump is composed of a pump section P and a motor section M for driving the pump section P, and has a structure in which liquid sucked into the pump section P circulates inside the motor section M.

[0018] As shown in FIG. 1, the pump device 1 includes a rotating shaft 5, an impeller 2 attached to the rotating shaft 5, a pump casing 3 that houses the impeller 2, a bracket 10 fixed to the pump casing 3, a motor 18 that rotates the rotating shaft 5, sliding bearings 30, 31 that rotatably support the rotating shaft 5, and a motor casing 4 that houses the rotating shaft 5, the motor 18, and the sliding bearings 30, 31.

[0019] The impeller 2 is attached to the rotating shaft 5 by a key structure 15. The key structure 15 is configured to restrict the relative rotation of the impeller 2 with respect to the rotating shaft 5, while allowing the impeller 2 to move in the axial direction CL of the rotating shaft 5. For example, the key structure 15 is composed of a protrusion (not shown) formed on the rotating shaft 5 and a fitting portion formed on the impeller 2 that fits into the protrusion. In this way, the impeller 2 is connected by the key structure 15 so as to be movable in the axial direction CL.

[0020] 1, a pump casing 3 and a bracket 10 are fastened to each other. The pump device 1 includes a seal member 9 (e.g., an O-ring) disposed between the pump casing 3 and the bracket 10. The seal member 9 prevents the liquid sucked into the pump casing 3 from leaking.

[0021] Motor 18 includes rotor 6 fixed to rotating shaft 5, and stator 7 arranged around rotor 6. Rotor 6 includes rotor core 6a fixed to rotating shaft 5, and a plurality of permanent magnets 6b embedded in rotor core 6a. Motor 18 having this configuration is a permanent magnet motor.

[0022] The stator 7 includes a stator core 7a and a plurality of coils 7b wound around the stator core 7a. The motor 18 includes insulating paper 8 disposed between the stator core 7a and the coils 7b. The insulating paper 8 insulates the stator core 7a from the coils 7b.

[0023] A lead wire 23 is connected to the coil 7b. The lead wire 23 is electrically connected to a power source (not shown) for supplying power to the motor 18. Power from the power source is supplied to the motor 18 through the lead wire 23.

[0024] The motor casing 4 includes a motor frame 12 connected to the bracket 10, and an end cover 11 that closes an open end of the motor frame 12. The end cover 11 is disposed on the opposite side of the motor frame 12 from the bracket 10.

[0025] The bracket 10, the motor frame 12, and the end cover 11 are connected in series in this order. Due to this connection, the motor unit M has an internal space formed by the bracket 10, the motor frame 12, and the end cover 11. The motor 18 is disposed in this internal space.

[0026] The pump device 1 includes a stator can 20 disposed between the rotor 6 and the stator 7, and a rotor can 21 that covers the rotor 6. The stator 7 is disposed in an annular space SP1 formed between the motor frame 12 and the stator can 20. The rotor 6 and the rotor can 21 are disposed in a space SP2 disposed inside the space SP1. The space SP2 is formed between the rotating shaft 5 and the stator can 20.

[0027] The pump device 1 includes a seal member 24 (e.g., an O-ring) disposed between the stator can 20 and the bracket 10, and a seal member 25 (e.g., an O-ring) disposed between the stator can 20 and the end cover 11. By disposing the seal members 24 and 25, the space SP1 is closed in a liquid-tight manner. The space SP1 is filled with a potting resin 22.

[0028] The rotating shaft 5 is rotatably supported by plain bearings 30, 31 arranged on both sides of the rotor 6. The plain bearing 30 is held by the bracket 10, and the plain bearing 31 is held by the end cover 11.

[0029] The pump device 1 includes a thrust plate 32 disposed between the plain bearing 30 and the rotor 6, and a thrust plate 33 disposed between the plain bearing 31 and the rotor 6. These thrust plates 32, 33 are fixed to the rotating shaft 5 and rotate integrally with the rotating shaft 5.

[0030] Fig. 2(a) is a diagram showing the suction port and discharge port of the pump device, and Fig. 2(b) is a diagram seen from the direction of the arrow A in Fig. 2(a). As shown in Fig. 2(a), the pump device 1 has a suction port 55 and a discharge port 56 formed in a pump casing 3. The suction port 55 and the discharge port 56 open along the axial direction CL. In one embodiment, as shown in Fig. 2(b), the suction port 55 and the discharge port 56 may open along a direction perpendicular to the axial direction CL (in other words, the upper surface of the pump casing 3).

[0031] When power is supplied to the motor 18, a magnetic field is generated in the stator 7, which rotates the rotor 6. The rotation of the rotor 6 is transmitted to the impeller 2 through the rotating shaft 5. When the impeller 2 rotates together with the rotating shaft 5, liquid is sucked into the pump casing 3 from the suction port 55.

[0032] As shown in Fig. 1, the pump device 1 has a vortex chamber 40 formed between a pump casing 3 and a bracket 10. The pump device 1 having such a structure is called a vortex type (in other words, a cascade type) canned motor pump.

[0033] The swirl chamber 40 communicates with the suction port 55 and the discharge port 56. Therefore, the liquid sucked into the pump casing 3 from the suction port 55 is introduced into the swirl chamber 40. The liquid introduced into the swirl chamber 40 is pressurized within the swirl chamber 40 by the rotation of the impeller 2, and is discharged to the outside through the discharge port 56.

[0034] Fig. 3 is a diagram showing a plurality of radial grooves formed in the impeller. As shown in Fig. 3, the impeller 2 has a plurality of radial grooves 2c formed in its periphery. The swirl chamber 40 is disposed so as to surround the plurality of radial grooves 2c.

[0035] The impeller 2 has a boss portion 2a connected to the rotary shaft 5, and a main plate portion 2b extending outward from the boss portion 2a. The boss portion 2a has a cylindrical shape extending along the axial direction CL, and is connected to the rotary shaft 5 by a key structure 15. The main plate portion 2b extends perpendicular to the axial direction CL. The radial grooves 2c are formed in the outermost portion of the main plate portion 2b.

[0036] 1, bracket 10 has a flow hole 10a for guiding a portion of the liquid introduced into swirl chamber 40 to the internal space (more specifically, space SP2) of motor unit M. Swirl chamber 40 and space SP2 communicate with each other through flow hole 10a. Therefore, a portion of the liquid pressurized by the rotation of impeller 2 is guided to space SP2 through flow hole 10a.

[0037] The liquid guided to space SP2 is divided into a circulation flow (first circulation flow) that flows through the gap between the plain bearing 30 and the rotating shaft 5, and a circulation flow (second circulation flow) that flows through the gap between the plain bearing 31 and the rotating shaft 5.

[0038] 1, the pump casing 3 has an impeller chamber (pump casing side impeller chamber) 41 arranged on the tip side of the rotating shaft 5. The impeller chamber 41 communicates with the swirl chamber 40 through a small gap (e.g., several tens of μm) formed between the main plate portion 2b of the impeller 2 and the pump casing 3.

[0039] The bracket 10 has an impeller chamber (bracket-side impeller chamber) 42 arranged on the opposite side of the impeller 2 from the impeller chamber 41. The impeller chamber 42 communicates with the swirl chamber 40 through a small gap formed between the impeller 2 and the bracket 10.

[0040] The plain bearing 30 has an introduction hole 30a that introduces a portion of the liquid introduced into the space SP2 into the impeller chamber 42. The introduction hole 30a extends parallel to the axial direction CL. A portion of the liquid introduced into the space SP2 is returned to the impeller chamber 42 through the introduction hole 30a of the plain bearing 30.

[0041] The liquid passing through the introduction hole 30a cools and lubricates the rotating shaft 5 and the sliding bearing 30. The liquid returned to the impeller chamber 42 passes through the gap between the bracket 10 and the main plate portion 2b of the impeller 2, and is returned to the low-pressure side of the swirl chamber 40. In this manner, the liquid forming the first circulation flow circulates between the space SP2 and the impeller chamber 42.

[0042] The liquid forming the second circulation flow passes through the narrow space between the rotor can 21 and the stator can 20. However, the rotor can 21 rotates together with the rotor 6 and the rotating shaft 5. Therefore, the liquid guided to the narrow space between the rotating rotor can 21 and the stationary stator can 20 may be repelled by centrifugal force and may not be able to pass through the narrow space smoothly. As a result, the second circulation flow may not be formed properly. Therefore, the pump device 1 has a structure for reliably and efficiently forming the second circulation flow. Details of such a structure will be described below.

[0043] 1, the rotating shaft 5 has an axial communicating hole 5a extending in the axial direction CL of the rotating shaft, and a radial communicating hole 50 connected to the axial communicating hole 5a and communicating with the impeller chamber 41. The axial communicating hole 5a is a blind hole. The radial communicating hole 50 extends perpendicular to the axial communicating hole 5a and opens at the outer periphery of the rotating shaft 5.

[0044] In this embodiment, the impeller 2 has a liquid outflow hole 51 connected to the radial communicating hole 50. The liquid outflow hole 51 is formed in the boss portion 2a of the impeller 2, and is disposed closer to the tip side of the rotary shaft 5 than the main plate portion 2b. The liquid outflow hole 51 is a through hole that extends perpendicular to the axial communicating hole 5a.

[0045] The plain bearing 31 has an introduction hole 31a for guiding the liquid that has passed through the narrow space to the axial communication hole 5a of the rotating shaft 5. The introduction hole 31a extends parallel to the axial direction CL. The liquid passing through the introduction hole 31a cools and lubricates the rotating shaft 5 and the plain bearing 31.

[0046] The end cover 11 has a recess 11a for guiding the liquid that has passed through the narrow space to the axial communicating hole 5a. The liquid that has passed through the introduction hole 31a and the recess 11a flows into the axial communicating hole 5a. The liquid that has flowed into the axial communicating hole 5a flows along the axial direction CL and is introduced into the radial communicating hole 50.

[0047] 4 is a diagram showing the liquid flowing through the axial communicating hole and the radial communicating hole. As shown in Fig. 4, when the rotating shaft 5 rotates, the liquid flowing through the radial communicating hole 50 is blown into the impeller chamber 41 through the liquid outflow hole 51 by the action of centrifugal force. In this way, the rotating shaft 5 can forcibly cause the liquid flowing through the radial communicating hole 50 to flow out into the impeller chamber 41 by its rotation.

[0048] According to this embodiment, by continuously flowing out the liquid, the liquid introduced into the motor section M is actively returned to the impeller chamber 41 through the axial communicating hole 5a and the radial communicating hole 50 by the pumping action.

[0049] With this configuration, the pump device 1 can actively pass the liquid introduced into the motor section M through the narrow space between the rotor can 21 and the stator can 20, and can actively and efficiently form the second circulation flow that circulates between the space SP2 and the impeller chamber 41. As a result, the pump device 1 can employ a small motor 18 with a high rotational speed, and can achieve a small water volume, high head, and compact size.

[0050] 3 and 4, the rotating shaft 5 has a plurality of (more specifically, two) radial communicating holes 50. When one radial communicating hole 50 is defined as a first radial communicating hole 50, the rotating shaft 5 has a second radial communicating hole 50 disposed on the opposite side to the first radial communicating hole 50 with respect to the center of the rotating shaft 5.

[0051] 3, the first radial communicating holes 50 and the second radial communicating holes 50 are disposed at equal intervals in the rotation direction of the rotating shaft 5. With this arrangement, a uniform centrifugal force acts on the liquid passing through the first radial communicating holes 50 and the second radial communicating holes 50. Therefore, the liquid can flow out of the first radial communicating holes 50 and the second radial communicating holes 50 efficiently.

[0052] In one embodiment, the rotating shaft 5 may have three or more radial communicating holes 50. Even in this case, the first radial communicating hole 50, the second radial communicating hole 50, and the third radial communicating hole 50 are preferably disposed at equal intervals in the rotational direction of the rotating shaft 5.

[0053] The number of liquid outflow holes 51 corresponds to the number of radial communication holes 50. In the embodiment shown in Fig. 3 and Fig. 4, the impeller 2 has two liquid outflow holes 51. When one liquid outflow hole 51 is defined as a first liquid outflow hole 51, the impeller 2 has a second liquid outflow hole 51 arranged on the opposite side of the first liquid outflow hole 51 with respect to its center. The first liquid outflow hole 51 and the second liquid outflow hole 51 are preferably arranged at equal intervals in the circumferential direction of the impeller 2.

[0054] 5 is a diagram showing another embodiment of the radial communication hole. In the above-mentioned embodiment, the rotating shaft 5 has a plurality of radial communication holes 50, and the impeller 2 has a number of liquid outflow holes 51 corresponding to the number of the radial communication holes 50. In one embodiment, as shown in FIG. 5, the rotating shaft 5 may have a single radial communication hole 50, and the impeller 2 may not have a liquid outflow hole 51. In one embodiment, the impeller 2 may have a single liquid outflow hole 51.

[0055] 5, the radial communicating hole 50 is formed closer to the tip of the rotary shaft 5 than the boss portion 2a of the impeller 2. Even with this configuration, the liquid introduced into the motor portion M is actively returned to the impeller chamber 41 by the pump action through the axial communicating hole 5a and the radial communicating hole 50.

[0056] In this embodiment, the pump device 1 has a structure that not only actively forms the second circulating flow, but also suppresses heat generation from the motor section M. More specifically, by employing the motor 18 as a permanent magnet motor, it is possible to reduce eddy current loss generated inside the rotor 6 compared to the case where a squirrel-cage rotor of an induction motor is employed.

[0057] Furthermore, such a configuration can increase the magnetic gap δ between the rotor 6 and the stator 7. For example, when an induction motor is used, the magnetic gap δ is about 1 mm, whereas when a permanent magnet motor (i.e., motor 18) is used, the magnetic gap δ is about 3 mm.

[0058] By increasing the magnetic gap δ, the gap between the stator can 20 and the rotor can 21 (i.e., the mechanical gap) can be increased, so that the churning loss of the rotor 6 can be reduced compared to the churning loss in an induction motor. As a result, the temperature rise of the liquid introduced inside the motor section M can be kept small.

[0059] In this embodiment, at least one of the rotor can 21 and the stator can 20 is made of a non-magnetic material (eg, resin, ceramic, etc.). With this configuration, no can loss occurs.

[0060] Fig. 6 is a diagram showing another embodiment of the pump device. Fig. 7 is a diagram showing the impeller in the pump shown in Fig. 6 as seen from the pump casing side. In the embodiment shown in Fig. 6 and Fig. 7, the rotating shaft 5 does not have the axial communicating hole 5a and the radial communicating hole 50, but instead has a shaft through hole 5b.

[0061] In order to improve pump efficiency, it is necessary to extremely reduce the gap between the impeller 2 and the pump casing 3 (and / or bracket 10) in the axial direction CL of the rotating shaft 5 when assembling the pump. Conventionally, workers carefully fix the impeller 2 to the rotating shaft 5 and position the impeller 2 so as to ensure a small gap of about several tens of μm.

[0062] However, such an assembly process is very complicated and time-consuming. Therefore, in the embodiment described below, a pump that can simplify the assembly process is provided. In this specification, the pump is a combination of an impeller 2 and a pump casing 3. The pump may include not only the impeller 2 and the pump casing 3, but also a bracket 10 as its components.

[0063] The main plate portion 2b has a first opposing surface 80A facing the pump casing 3 (see FIG. 7). The first opposing surface 80A is disposed inside the radial grooves 2c and outside the boss portion 2a. In other words, the first opposing surface 80A is an annular surface disposed between the radial grooves 2c and the boss portion 2a.

[0064] In the embodiment shown in Fig. 7, the main plate portion 2b has a plurality of dynamic pressure grooves 60 formed in the first opposing surface 80A. The dynamic pressure grooves 60 are grooves for generating dynamic pressure between the impeller 2 and the pump casing 3. The depth of the dynamic pressure grooves 60 is determined according to the viscosity of the handled fluid. For example, the dynamic pressure grooves 60 may have a depth of several µm to several tens of µm.

[0065] The multiple dynamic pressure grooves 60 are disposed inside the multiple radial grooves 2c, and are formed at equal intervals over the entire main plate portion 2b along the circumferential direction of the main plate portion 2b. When the impeller 2 rotates together with the rotating shaft 2, the liquid present in the dynamic pressure grooves 60 generates dynamic pressure (i.e., a liquid film) in the gap between the impeller 2 and the pump casing 3. Due to the generation of dynamic pressure, a certain gap is formed between the impeller 2 and the pump casing 3, and the impeller 2 is supported by the pump casing 3 without contacting it.

[0066] In the embodiment shown in Fig. 7, the multiple dynamic pressure grooves 60 are spiral grooves that extend in a spiral shape from the center of the impeller 2 outward. However, as long as dynamic pressure can be generated, the shape of the dynamic pressure grooves 60 is not limited to the embodiment shown in Fig. 7. In one embodiment, the multiple dynamic pressure grooves 60 may have a shape that extends linearly from the center of the impeller 2 outward.

[0067] According to this embodiment, since the impeller 2 has the dynamic pressure grooves 60, it is not necessary to position the impeller 2. More specifically, an operator carefully fixes the impeller 2 to the rotating shaft 5 so as to secure a small gap of about several tens of μm, thereby eliminating the need for a complicated assembly operation of positioning the impeller 2. As a result, the assembly operation of the pump can be simplified.

[0068] By forming the dynamic pressure grooves 60, a liquid film is formed in the gap between the impeller 2 and the pump casing 3 during operation of the pump device 1. The liquid film can reduce the flow rate of liquid leaking through the gap between the impeller 2 and the pump casing 3. Therefore, high efficiency of the pump can be achieved.

[0069] Fig. 8 is a view of the impeller in the pump shown in Fig. 6 as seen from the bracket side. As shown in Fig. 8, the main plate portion 2b has a second opposing surface 80B that faces the bracket 10. The second opposing surface 80B is disposed inside the multiple radial grooves 2c and outside the boss portion 2a. The second opposing surface 80B is disposed on the opposite side to the first opposing surface 80A.

[0070] 8, the main plate portion 2b has a plurality of dynamic pressure grooves 61 formed in the second opposing surface 80B. The dynamic pressure grooves 61 formed in the second opposing surface 80B have the same structure as the dynamic pressure grooves 60 formed in the first opposing surface 80A. Therefore, a detailed description of the dynamic pressure grooves 61 will be omitted.

[0071] 7 and 8, in this embodiment, the impeller 2 has dynamic pressure grooves 60 formed in the first opposing surface 80A and dynamic pressure grooves 61 formed in the second opposing surface 80B, but the dynamic pressure grooves do not necessarily have to be formed in both the first opposing surface 80A and the second opposing surface 80B. In one embodiment, the main plate portion 2b may have a plurality of dynamic pressure grooves formed in at least one of the first opposing surface 80A and the second opposing surface 80B.

[0072] Fig. 9 is a diagram showing another embodiment of the pump device. As shown in Fig. 9, the embodiment described with reference to Figs. 1 to 5 and the embodiment described with reference to Figs. 6 to 8 may be combined.

[0073] More specifically, the pump device 1 may include a radial communicating hole 50 (and a liquid outflow hole 51 formed in the boss portion 2a of the impeller 2) formed in the rotating shaft 5, and a plurality of dynamic pressure grooves 60 (and / or a plurality of dynamic pressure grooves 61) formed in the first opposing surface 80A (and / or the second opposing surface 80B). In this case, the rotating shaft 5 has an axial communicating hole 5a connected to the radial communicating hole 50, instead of having an axial through hole 5b (see FIG. 6).

[0074] With such a structure, the pump device 1 forms a liquid film by the multiple dynamic pressure grooves 60 (and / or the multiple dynamic pressure grooves 61), and actively forms a second circulating flow by the radial communicating holes 50 (and the liquid outflow holes 51).

[0075] According to this embodiment, a liquid film is formed to prevent the impeller 2 from contacting the pump casing 3 (and / or the bracket 10), thereby making it possible to provide an effect of reliably ensuring the second circulating flow.

[0076] Figures 10 and 11 are diagrams showing another embodiment of the pump device. Figure 12 is a diagram showing an impeller in the pump device shown in Figures 10 and 11. In this embodiment, configurations that are not particularly described are the same as those in the above-mentioned embodiment, so duplicated descriptions will be omitted.

[0077] In the above-described embodiment, the pump device 1 is a vortex type (in other words, a cascade type) pump device, but the impeller 2 having the dynamic pressure grooves 60, 61 does not necessarily have to be applied only to vortex type pump devices and can be applied to other pump devices 1.

[0078] 10, the pump device 1 includes a pump casing 3 as a component of the pump section P, and a motor casing 4 as a component of the motor section M. The pump casing 3 includes a casing body 3A and a casing cover 3B that closes the casing body 3A. The motor casing 4 includes a motor frame 12, and a bracket 10 and an end cover 11 arranged on both sides of the motor frame 12.

[0079] The impeller 2 is housed in a pump casing 3, and the motor 18 is housed in a motor casing 4. The rotating shaft 5 passes through a casing cover 3B of the pump casing 3, and a shaft seal device 65 is disposed between the rotating shaft 5 and the casing cover 3B. The shaft seal device 65 is, for example, a mechanical seal, and prevents the liquid sucked into the pump casing 3 from leaking.

[0080] The rotating shaft 5 is rotatably supported by a bearing 70 supported by the bracket 10 and a bearing 71 supported by the end cover 11. The bearings 70 and 71 are, for example, ball bearings.

[0081] In the embodiment shown in FIG. 11, the pump device 1 includes a motor side rotating shaft 5A arranged in the motor section M, a pump side rotating shaft 5B arranged in the pump section P, and a coupling 90 that fastens the motor side rotating shaft 5A and the pump side rotating shaft 5B to each other.

[0082] In this manner, the pump device 1 may be provided with a rotating shaft 5 that transmits the rotational force of the motor 18 directly to the impeller 2 (see FIG. 10), or may be provided with rotating shafts 5A, 5B that transmit the rotational force of the motor 18 to the impeller 2 via a coupling 90 (see FIG. 11).

[0083] 10, 11, and 12, the rotating shaft 5 (or the pump-side rotating shaft 5B) does not have an axial communicating hole 5a and a radial communicating hole 50 formed therein. As shown in Fig. 12, the impeller 2 has a dynamic pressure groove 60 formed in its first opposing surface 80A and / or a dynamic pressure groove 61 formed in its second opposing surface 80B.

[0084] In the present embodiment, the pump device 1 can also form a liquid film between the impeller 2 and the pump casing 3. Therefore, an operator can omit the troublesome assembly work of positioning the impeller 2.

[0085] The above-described embodiments have been described for the purpose of enabling a person having ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments are naturally possible for a person skilled in the art, and the technical idea of ​​the present invention can 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 according to the technical idea defined by the claims. [Explanation of symbols]

[0086] 1 Pumping equipment 2 Impeller 2a Boss part 2b Main plate part 2c radial groove 3 Pump casing 3A Casing Body 3B Casing cover 4 Motor casing 5 Rotation Axis 5A Motor side rotating shaft 5B Pump side rotating shaft 5a Axial communication hole 5b Shaft through hole 6 Rotor 6a Rotor core 6b Permanent magnet 7 Stator 7a Stator core 7b Coil 10 Bracket 10a Distribution hole 11 End cover 11a Recess 12 Motor Frame 15 Key Structure 18 Motor 20 Stator cancel 21 Rotorcan 22 Potting resin 23 Outlet Wire 24,25 Sealing material 30 Plain bearing 30a Introduction hole 31 Plain bearings 31a Introduction hole 32,33 Thrust plate 40 vortex chamber 41 Impeller chamber (pump casing side impeller chamber) 42 Impeller chamber (bracket side impeller chamber) 50 Radial communication hole 51 Liquid outflow hole 55 Intake port 56 Discharge port 60,61 Hydrodynamic groove 65 Shaft sealing device 70,71 Bearings 80A 1st opposing surface 80B 2nd facing surface P Pump section M Motor section CL axial direction SP1 Space SP2 Space

Claims

1. A rotation axis; An impeller attached to the rotating shaft; a pump casing having an impeller chamber disposed on a tip side of the rotating shaft; a motor that rotates the rotation shaft, The rotation shaft is an axial communication hole extending in the axial direction of the rotating shaft; a radial communication hole connected to the axial communication hole, A canned motor pump, wherein the radial communicating hole is in communication with the impeller chamber.

2. When the radial communicating hole is defined as a first radial communicating hole, 2. The canned motor pump according to claim 1, wherein the rotating shaft has a second radial communicating hole disposed on an opposite side of the first radial communicating hole with respect to a center of the rotating shaft.

3. 2. The canned motor pump according to claim 1, wherein the impeller has a liquid outlet hole connected to the radial communication hole.

4. When the liquid outlet hole is defined as a first liquid outlet hole, 4. The canned motor pump according to claim 3, wherein the impeller has a second liquid outlet hole disposed on an opposite side of the first liquid outlet hole with respect to the center of the impeller.

5. The impeller comprises: A boss portion connected to the rotating shaft; a main plate portion extending outward from the boss portion, 4. The canned motor pump according to claim 3, wherein the liquid outflow hole is formed in the boss portion.

6. 6. The canned motor pump according to claim 5, wherein the liquid outflow hole is disposed closer to a tip end of the rotary shaft than the main plate portion.

7. 2. The canned motor pump according to claim 1, wherein the canned motor pump is a vortex type canned motor pump having a vortex chamber surrounding a plurality of radial grooves formed on a periphery of the impeller.

8. The motor is A rotor having a permanent magnet; 2. The canned motor pump according to claim 1, further comprising: a stator surrounding said rotor.

9. The canned motor pump includes: A rotor can covering the rotor; A stator can is disposed between the rotor and the stator, 9. The canned motor pump according to claim 8, wherein at least one of the rotor can and the stator can is constructed from a non-magnetic material.

Images