JP2011106323A - Motor pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor pump preventing thermal deformation of a bulkhead disposed between an impeller and a motor stator. <P>SOLUTION: The motor pump includes the impeller 1 having a plurality of permanent magnets 5 embedded therein, a pump casing 2 holding the impeller 1, the motor stator 6 including a plurality of stator coils 6B, a motor casing 3 holding the motor stator 6, and a dynamic pressure bearing 10 supporting the impeller 1. The dynamic pressure bearing 10 and the motor stator 6 are disposed at a suction side of the impeller 1. The motor casing 2 includes a side wall part 32 positioned between the impeller 1 and the stator coil 6B, and a plurality of radially extending ribs 36. The side wall part 32 is fixed on the plurality of ribs 36. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a motor pump that rotates an impeller embedded with a permanent magnet by a magnetic field generated by a motor stator.

  As a conventional example of a motor pump that rotates an impeller embedded with a permanent magnet by a magnetic field generated by a motor stator, a pump described in Patent Document 1 is known. The motor pump described in Patent Document 1 includes an impeller in which a permanent magnet is embedded, and a motor stator disposed so as to face the impeller, and the impeller is rotatably supported by one spherical bearing. Has been. The spherical bearing is a so-called dynamic pressure bearing, and can support the impeller in a tiltable manner while rotatably supporting the impeller.

  The motor stator has a plurality of stator coils, and when a three-phase current is passed through these stator coils, a rotating magnetic field is generated. This rotating magnetic field acts on a permanent magnet embedded in the impeller and rotationally drives the impeller. When the liquid handled by the pump comes into contact with the motor stator, electric leakage is caused. Therefore, a thin partition is provided between the motor stator and the impeller to prevent the liquid from entering the motor stator.

  The rotating magnetic field generated by the motor stator acts on the permanent magnet of the impeller through the partition wall. If this partition is made of metal, an eddy current is generated in the partition as the rotating magnetic field passes, causing heat generation of the partition and a reduction in motor efficiency. Therefore, in order to prevent the generation of such eddy currents, the partition walls are usually made of resin. The resin partition has an advantage that even if the stator coil comes into contact with the partition, the electrical insulation of the stator coil is maintained and there is no risk of ground fault.

  However, since the partition wall is formed thin as described above, if the pump is used under conditions where the liquid to be transferred is hot or the temperature of the partition wall changes drastically, thermal expansion or contraction will occur. The partition wall is deformed. Further, the motor stator itself generates heat due to energization, and the partition wall may be deformed by thermal expansion. Usually, since the gap between the impeller and the partition is small, when the partition is deformed, the rotating impeller may come into contact with the partition.

  Furthermore, the liquid staying in the gap between the impeller and the partition wall is heated by receiving heat from the motor stator, and may reach a boiling point and evaporate depending on operating conditions. When the liquid evaporates, the lubrication of the hydrodynamic bearing is hindered and the bearing is broken. In addition, if the pump handling liquid contains foreign matter such as rust or dust on the pipe, foreign matter may enter the dynamic pressure bearing and damage the dynamic pressure bearing. Furthermore, if foreign matter made of magnetic material is contained in the liquid, these foreign matter accumulates on the surface of the impeller with a built-in permanent magnet, and finally the deposited foreign matter comes into contact with the partition wall to wear the partition wall or impeller. I will let you.

Japanese Patent No. 2544825

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a motor pump that can prevent a partition disposed between an impeller and a motor stator from being deformed by heat. To do.

  In order to achieve the above-described object, one aspect of the present invention includes an impeller in which a plurality of permanent magnets are embedded, a pump casing that houses the impeller, a motor stator having a plurality of stator coils, A motor pump comprising a motor casing that houses the motor stator and a hydrodynamic bearing that supports the impeller, wherein the hydrodynamic bearing and the motor stator are arranged on a suction side of the impeller. The motor casing has a side wall portion located between the impeller and the stator coil, and a plurality of radially extending ribs, and the side wall portion is fixed to the plurality of ribs. Features.

In a preferred aspect of the present invention, the motor casing is formed with a housing space for housing the motor stator, and the motor casing has an inner frame portion having an inner peripheral wall forming the housing space, and the housing. An outer frame portion having an outer peripheral wall that forms a space is provided, and the plurality of ribs are fixed to the inner peripheral wall and the outer peripheral wall.
In a preferred aspect of the present invention, there is provided at least one return flow path for returning the liquid discharged from the impeller to a liquid inlet of the impeller from a gap between the impeller and the side wall portion. .

In a preferred aspect of the present invention, a motor cover made of metal is attached to the motor casing, and the motor cover is in contact with the motor stator.
In a preferred aspect of the present invention, a cooling chamber through which a coolant flows is attached to the motor cover.

In a preferred aspect of the present invention, a strainer is further provided between the outer peripheral surface of the impeller and the inner peripheral surface of the pump casing.
In a preferred aspect of the present invention, the strainer includes a curved portion having a shape that smoothly connects the wall surface of the volute chamber of the pump casing and the outer peripheral surface of the impeller.

  According to the present invention described above, since the side wall portion (corresponding to the partition wall) of the motor casing is reinforced by the plurality of ribs, the deformation of the side wall portion due to heat can be prevented.

It is sectional drawing which shows the motor pump which concerns on one Embodiment of this invention. It is the figure which looked at the motor pump shown in FIG. 1 from the arrow A direction. It is a top view which shows the permanent magnet currently embed | buried under the impeller. 4A is a plan view showing the motor stator, and FIG. 4B is a cross-sectional view taken along line BB shown in FIG. 4A. 5 (a) is a plan view of the motor casing, FIG. 5 (b) is a cross-sectional view taken along the line C-C shown in FIG. 5 (a), and FIG. 5 (c) is the motor shown in FIG. 5 (b). FIG. 6 is a view of a part of the casing as seen from the direction indicated by arrow D. It is sectional drawing which shows a return flow path. It is sectional drawing which shows the other example of a return flow path. It is a figure which shows the modification which provided the cooling chamber in the motor pump shown in FIG. It is sectional drawing which shows the motor pump which concerns on other embodiment of this invention. It is sectional drawing of the strainer shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view showing a motor pump according to an embodiment of the present invention, and FIG. 2 is a view of the motor pump shown in FIG. The motor pump includes an impeller 1 in which a plurality of permanent magnets 5 are embedded, a motor stator 6 that generates magnetic force acting on the permanent magnets 5, a pump casing 2 that houses the impeller 1, and a motor fixed A motor casing 3 that houses the child 6 and a bearing 10 that supports the radial load and thrust load of the impeller 1 are provided. The motor stator 6 and the bearing 10 are arranged on the suction side of the impeller 1.

  The pump casing 2 and the motor casing 3 are fixed to each other by a plurality of connecting bolts 8 shown in FIG. An O-ring 9 as a seal member is provided between the pump casing 2 and the motor casing 3. The impeller 1 and the motor casing 3 are opposed to each other through a minute gap, and the impeller 1 rotates when a rotating magnetic field generated by the motor stator 6 acts on the permanent magnet 5. The gap between the impeller 1 and the motor casing 3 is preferably as small as possible so as not to contact each other. Specifically, it is preferable to form the gap within a range of 0.5 mm to 1 mm.

  The impeller 1 is rotatably supported by a single bearing 10. This bearing 10 is a sliding bearing (dynamic pressure bearing) using the dynamic pressure of liquid. The bearing 10 includes a combination of a rotating side bearing element 11 and a fixed side bearing element 12 that are gently engaged with each other. The rotation-side bearing element 11 is fixed to the impeller 1 and is disposed so as to surround the liquid inlet of the impeller 1. The stationary bearing element 12 is fixed to the motor casing 3 and is disposed on the suction side of the rotating bearing element 11. The fixed-side bearing element 12 has a radial surface 12 a that supports the radial load of the impeller 1 and a thrust surface 12 b that supports the thrust load of the impeller 1. The radial surface 12 a is parallel to the axis of the impeller 1, and the thrust surface 12 b is perpendicular to the axis of the impeller 1.

  The rotation-side bearing element 11 has an annular shape, the inner peripheral surface of the rotation-side bearing element 11 faces the radial surface 12a of the fixed-side bearing element 12, and the side surface of the rotation-side bearing element 11 is the fixed-side bearing element. It faces 12 thrust surfaces 12b. Minute gaps are formed between the inner peripheral surface of the rotation-side bearing element 11 and the radial surface 12a, and between the side surface of the rotation-side bearing element 11 and the thrust surface 12b. Further, spiral grooves (not shown) for generating dynamic pressure are formed on the inner peripheral surface and the side surface of the rotation-side bearing element 11.

  A part of the liquid discharged from the impeller 1 is guided to the bearing 10 through a minute gap between the impeller 1 and the motor casing 3. When the rotation-side bearing element 11 rotates together with the impeller 1, fluid dynamic pressure is generated between the rotation-side bearing element 11 and the fixed-side bearing element 12, whereby the impeller 1 is supported by the bearing 10 in a non-contact manner. The Since the fixed-side bearing element 12 supports the rotating-side bearing element 11 by the orthogonal radial surface 12 a and thrust surface 12 b, the tilt of the impeller 1 is restricted by the bearing 10. The bearing 10 (the rotation-side bearing element 11 and the fixed-side bearing element 12) is made of a material having excellent wear resistance such as ceramic or carbon.

  A suction port 15 having a suction port 15 a is connected to the motor casing 3. The suction port 15 has a flange shape and is connected to a suction line (not shown). Liquid flow paths 15b, 3a, and 10a are formed in the central portions of the suction port 15, the motor casing 3, and the bearing 10, respectively. These liquid flow paths 15b, 3a, and 10a are connected in a line and constitute one liquid flow path that extends from the suction port 15a to the liquid inlet of the impeller 1. A discharge port 16 having a discharge port 16a is provided on the side surface of the pump casing 2, and the liquid pressurized by the rotating impeller 1 is discharged through the discharge port 16a. The motor pump according to the present embodiment is a so-called end-top type motor pump in which the suction port 15a and the discharge port 16a are orthogonal to each other.

  The impeller 1 is formed of a nonmagnetic material that is slippery and difficult to wear. For example, a resin such as Teflon (registered trademark) or PPS (polyphenylene sulfide) or ceramic is preferably used. The pump casing 2 and the motor casing 3 can also be formed from the same material as the impeller 1. The rotation-side bearing element 11 of the bearing 10 may be omitted, a spiral groove may be formed in a part of the impeller 1, and the impeller 1 may be supported by the radial surface 12a and the thrust surface 10b of the fixed-side bearing element 12. .

  FIG. 3 is a plan view showing the permanent magnet 5 embedded in the impeller 1. As shown in FIG. 3, the plurality of permanent magnets 5 are arranged in an annular shape, and S poles and N poles are alternately arranged. Each permanent magnet 5 has a sector shape, and in this embodiment, the number of permanent magnets 5 is eight (that is, eight poles). As shown in FIG. 1, an annular magnet yoke (magnetic body) 19 is embedded in the impeller 1 adjacent to the plurality of permanent magnets 5. The permanent magnet 5 is disposed on the suction side of the magnet yoke 19. The permanent magnet 5 and the motor stator 6 are arranged so as to face each other, and the motor stator 6 is arranged on the suction side of the impeller 1. The motor stator 6 is disposed in the motor casing 3, and the accommodation space in which the motor stator 6 is accommodated is closed by the motor cover 20.

  FIG. 4A is a plan view showing the motor stator 6, and FIG. 4B is a cross-sectional view taken along line BB shown in FIG. 4A. As shown in FIGS. 4 (a) and 4 (b), the motor stator 6 includes a stator core 6A having a plurality of teeth 6a, a stator coil 6B wound around these teeth 6a, have. The teeth 6a and the stator coil 6B are arranged in an annular shape. In this embodiment, the stator coil 6B is wound around each of the six teeth 6a, and the number of magnetic poles is six. The impeller 1 and the motor stator 6 are arranged concentrically with the bearing 10 and the suction port 15a.

  Three lead wires 17 (see FIG. 2) are connected to the stator coil 6B, and the terminals of the lead wires 17 are connected to a drive circuit (not shown). This drive circuit is a device that controls the timing of the current supplied to each stator coil 6B using a switching element. More specifically, the drive circuit controls the timing of the current supplied to each stator coil 6B based on the position of the rotating permanent magnet 5. Examples of the method for detecting the position of the permanent magnet 5 include a method using a position sensor such as a Hall element, a method using a counter electromotive force generated in the stator coil 6B without using a position sensor, and the like. The motor pump according to the present embodiment may employ either a sensor driving method using a position sensor or a sensorless driving method that does not use a position sensor.

  The drive circuit described above appropriately switches energization of the stator coil 6B based on the position of the permanent magnet 5, and thereby the permanent magnet 5, that is, the impeller 1 rotates. When the impeller 1 rotates, the 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 discharged from the discharge port 16a. While the impeller 1 is transferring liquid, the back surface of the impeller 1 is pressed to the suction side (that is, toward the suction port 15a) by the pressurized liquid. Since the bearing 10 is disposed on the suction side of the impeller 1, the bearing 10 supports the thrust load of the impeller 1 from the suction side. According to the configuration according to the present embodiment, the radial load and the thrust load of the impeller 1 can be supported in a non-contact manner by the single bearing 10, thereby realizing a compact motor pump that does not generate particles. Can do.

  5 (a) is a plan view of the motor casing 3, FIG. 5 (b) is a cross-sectional view taken along the line CC of FIG. 5 (a), and FIG. 5 (c) is shown in FIG. 5 (b). FIG. 4 is a view of a part of the motor casing 3 as seen from the direction indicated by the arrow D. The motor casing 3 includes an outer frame part 30, an inner frame part 31, and a side wall part 32 that connects the outer frame part 30 and the inner frame part 31. The outer frame portion 30 is formed with a plurality of through holes 34 into which the above-described connecting bolts 8 (see FIG. 2) are inserted. The inner frame portion 31 has a substantially cylindrical shape, and a liquid flow path 3a through which a liquid passes is formed at the center thereof. The side wall part 32 has an annular shape, and the inner frame part 31 and the outer frame part 30 are connected by the side wall part 32. The outer frame portion 30 is formed with an outer peripheral wall 30a, and the inner frame portion 31 is formed with an inner peripheral wall 31a. The outer peripheral wall 30a, the inner peripheral wall 31a, and the side wall portion 32 form an annular storage space in which the motor stator 6 is stored.

  The motor casing 3 further includes a plurality of ribs 36 that are fixed to the side wall portion 32. These ribs 36 extend radially so as to cross the side wall portion 32 and are arranged at equal intervals in the circumferential direction. The ribs 36 are fixed to the inner peripheral wall 31a and the outer peripheral wall 30a, and connect the inner frame part 31 and the outer frame part 30 to each other. The inner surface of the side wall portion 32 is fixed to the radially extending ribs 36, whereby the mechanical strength of the side wall portion 32 is reinforced. The accommodation space described above is partitioned into a plurality of segments by the ribs 36, and the stator coils 6B of the motor stator 6 are accommodated in these segments, respectively. The number of ribs 36 is preferably the same as the number of stator coils 6B as in the present embodiment. In this case, each rib 36 is sandwiched between the stator coils 6B.

  The outer frame part 30, the inner frame part 31, the side wall part 32, and the rib 36 are integrally formed. From the viewpoint of securing electrical insulation of the motor stator 6 and preventing the generation of eddy currents, the motor casing 3 is made of a nonmetallic material. As a material constituting the motor casing 3, a resin is preferably used. More specifically, an inexpensive resin such as PPS (polyphenylene sulfide) or PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer) is used. The resin motor casing 3 has an advantage that even if the stator coil 6B comes into contact with the motor casing 3, the electrical insulation of the stator coil 6B is maintained, and there is no possibility of a ground fault. As a method of forming the motor casing 3 with resin, injection molding may be mentioned.

  As shown in FIG. 1, the side wall portion 32 of the motor casing 3 is disposed to face the suction side surface of the impeller 1. That is, the side wall part 32 is located between the impeller 1 and the stator coil 6 </ b> B and functions as a partition wall that partitions the impeller 1 and the motor stator 6. The rotating magnetic field generated by the motor stator 6 reaches the permanent magnet 5 of the impeller 1 through the side wall portion 32. Therefore, the side wall 32 of the motor casing 3 is preferably as thin as possible. For example, the side wall 32 of the motor casing 3 has a thickness of several mm.

  The motor pump according to the present embodiment is used for transferring or circulating a liquid having a wide range of temperatures (for example, −40 ° C. to 200 ° C.). During operation of the motor pump, the side wall 32 of the motor casing 3 receives heat generated from the motor stator 6. In addition, the side wall 32 of the motor casing 3 is heated or cooled by contact with the liquid. Even under such operating conditions, the side wall 32 is reinforced by the plurality of ribs 36, so that thermal deformation hardly occurs. Therefore, contact between the impeller 1 and the motor casing 3 during the pump operation can be prevented.

  Further, each rib 36 is not only fixed to the side wall portion 32 but also fixed to the inner frame portion 31 and the outer frame portion 30. Therefore, the rigidity of the entire motor casing 3 can be increased. Moreover, these ribs 36 not only function as a reinforcing member of the motor casing 3 but also function as an insulating member that ensures electrical insulation between the adjacent stator coils 6B. That is, by providing the same number of ribs 36 as the stator coils 6B, each rib 36 is sandwiched between the stator coils 6B, and electrical insulation between the stator coils 6B is secured by the ribs 36.

  As shown in FIG. 5 (c), a plurality of (three in this embodiment) return flow paths 37 are formed in the inner frame portion 31 of the motor casing 3. These return flow paths 37 are formed as grooves on the inner peripheral surface of the inner frame portion 31. The return flow path 37 is preferably provided inside the rib 36 in the radial direction. This is because the end portion of the rib 36 is provided with a fillet portion (thick portion), and the strength of the motor casing 3 can be ensured while forming a return flow path 37 as a groove. .

  FIG. 6 is a cross-sectional view showing the return channel 37. As shown in FIG. 6, the return flow path 37 extends from the gap between the impeller 1 and the motor casing 3 to the liquid flow path. Therefore, part of the liquid pressurized by the impeller 1 is returned to the liquid inlet of the impeller 1 through the clearance between the impeller 1 and the motor casing 3 and the return flow path 37 in this order. Part of the liquid that has passed through the gap between the impeller 1 and the motor casing 3 enters between the rotation-side bearing element 11 and the fixed-side bearing element 12 of the bearing 10, and provides the dynamic pressure necessary to support the impeller 1. generate.

  The return flow path 37 is provided to supply sufficient liquid to the bearing 10. If there is not enough liquid between the rotating side bearing element 11 and the fixed side bearing element 12 of the bearing 10, the bearing 10 may be burned. In particular, when the liquid in the gap between the impeller 1 and the motor casing 3 boils due to heat generation or fluid friction of the motor stator 6, the liquid between the rotating side bearing element 11 and the stationary side bearing element 12 is depleted. End up. Therefore, in the present embodiment, the return flow path 37 is provided so that a liquid flow is always formed in the gap between the suction side surface of the impeller 1 and the motor casing 3. By providing the return flow path 37, evaporation of the liquid due to heat from the motor stator 6 is suppressed, and the bearing 10 can generate a dynamic pressure sufficient to support the impeller 1.

  The pump performance decreases as the number of return flow paths 37 increases, so the number of return flow paths 37 does not have to be the same as the number of ribs 36. In the present embodiment, three return channels 37 are provided for the six ribs 36. Instead of the return flow path 37 shown in FIG. 6, as shown in FIG. 7, a return flow path 37 is provided between the side surface (surface on the suction side) of the impeller 1 and the rotation-side bearing element 11 of the bearing 10. Also good. Also in this example, a part of the liquid pressurized by the impeller 1 is returned to the liquid inlet of the impeller 1 through the clearance between the impeller 1 and the motor casing 3 and the return flow path 37 in this order.

  As shown in FIG. 1, the motor stator 6 is sandwiched between the motor casing 3 and the motor cover 20. The motor cover 20 includes a cover plate 20 a that closes the accommodation space of the motor stator 6 and a fixing ring 20 b that protrudes from the surface of the cover plate 20 a toward the motor stator 6. The cover plate 20a and the fixing ring 20b are integrally formed. The cover plate 20a has a disk shape as a whole, and a hole into which the suction port 15 is inserted is formed at the center thereof. The fixing ring 20 b is in contact with the stator core 6 </ b> A of the motor stator 6 and presses the motor stator 6 against the side wall portion 32 of the motor casing 3. Thus, the motor cover 20 not only functions as a lid for the accommodation space of the motor stator 6 but also functions as a fixing member that fixes the position of the motor stator 6.

  The motor cover 20 is made of a metal such as stainless steel. The reason why the motor cover 20 is made of metal is as follows. When a current is passed through the stator coil 6B of the motor stator 6, the stator coil 6B generates heat. Part of the heat is transmitted to the liquid via the side wall 32 of the motor casing 3, and the other part is dissipated to the outside air via the motor casing 3 and the motor cover 20. However, if both the motor casing 3 and the motor cover 20 are made of resin, it is difficult to efficiently dissipate the heat generated in the motor stator 6 because the thermal conductivity of the resin is low.

  Therefore, in the motor pump of this embodiment, the motor cover 20 is made of metal, and the heat generated in the motor stator 6 is efficiently released to the outside air through the motor cover 20. Since the fixing ring 20 b of the motor cover 20 is in contact with the motor stator 6, the heat of the motor stator 6 is transmitted to the motor cover 20 and further dissipated from the motor cover 20 to the outside air. The cover plate 20a and the fixing ring 20b may be separate members. Also in this case, both the cover plate 20a and the fixing ring 20b are made of metal.

  In the motor pump according to the present embodiment, no metal is used for a component member (hereinafter referred to as a liquid contact member) that comes into contact with the handling liquid. That is, resin or ceramic with high chemical resistance is used for the suction port 15, the pump casing 2, the motor casing 3, the bearing 10, the impeller 1, and the discharge port 16 that are liquid contact members. Examples of preferable resins include fluororesins such as PTFE (polytetrafluoroethylene) and PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), and the like. Is mentioned.

  The suction port 15 is inserted into the hole formed in the center of the motor cover 20 described above, and the motor cover 20 and the suction port 15 are configured as separate members. Therefore, the motor cover 20 formed of metal does not contact the handling liquid of the pump. Thus, since the motor pump according to the present embodiment does not use metal for the liquid contact member, it can be used for transfer of highly corrosive chemicals or ultrapure water that must avoid the outflow of metal ions. it can.

  In order to improve the cooling efficiency of the motor stator 6, a cooling chamber 40 may be provided in the motor cover 20 as shown in FIG. 8. FIG. 8 is a view showing a modification in which the cooling chamber 40 is provided in the motor pump shown in FIG. As shown in FIG. 8, the cooling chamber 40 is attached to the outer surface of the motor cover 20. The cooling chamber 40 has an annular shape, and has a coolant inlet 40A and a coolant outlet 40B. The cooling liquid (for example, cooling water) flows into the cooling chamber 40 from a cooling liquid supply source (not shown) through the cooling liquid inlet 40A, flows inside the cooling chamber 40, and is discharged from the cooling liquid outlet 40B. According to such a configuration, the heat generated in the motor stator 6 is transmitted to the coolant through the metal motor cover 20, so that the heat of the motor stator 6 can be efficiently released to the outside of the motor pump. it can.

FIG. 9 is a cross-sectional view showing a motor pump according to another embodiment of the present invention. The configuration of the present embodiment not specifically described is the same as the configuration of the motor pump shown in FIG.
If the pump handling liquid contains foreign matter such as rust or dust on the pipe, the foreign matter may enter the bearing 10 which is a hydrodynamic bearing, causing damage to the bearing 10. Further, when foreign substances made of a magnetic material are contained in the liquid, these foreign substances accumulate on the surface of the impeller 1 incorporating the permanent magnet 5, and finally the accumulated foreign substances come into contact with the side wall portion 32 of the motor casing 3. As a result, the side wall 32 and the impeller 1 are worn.

  Therefore, a strainer 50 that removes foreign matters from the liquid is disposed between the outer peripheral surface of the impeller 1 and the inner peripheral surface of the motor casing 3. The strainer 50 is a filter made of a metal plate on which a mesh is formed. The size of the mesh is 1 μm to 100 μm, preferably 10 μm to 20 μm. 10 is a cross-sectional view of the strainer 50 shown in FIG. The strainer 50 is annular, and more specifically has a cylindrical shape with a short axial length. The tip of the strainer 50 is bent radially inward to form a curved portion 50a. The curved portion 50 a is formed in accordance with the wall surface position of the volute chamber 2 a of the pump casing 2.

  A gap through which liquid passes is formed between the outer peripheral surface of the impeller 1 and the inner peripheral surface of the pump casing 2, and the strainer 50 is inserted into this gap. By fitting the outer peripheral surface of the strainer 50 to the inner peripheral surface of the pump casing 2, the position of the strainer 50 is fixed. The curved portion 50 a of the strainer 50 is formed so as to close a gap between the outer peripheral surface of the impeller 1 and the inner peripheral surface of the pump casing 2, whereby foreign matters are removed from the liquid passing through the gap by the strainer 50. The liquid that has passed through the strainer 50 is guided to the bearing 10 through a gap between the impeller 1 and the side wall portion 32 of the motor casing 3. Therefore, foreign matter does not enter the bearing 10 and the performance of the bearing 10 is maintained. As described above, according to the present embodiment, it is possible to provide a motor pump capable of maintaining the performance of the bearing 10 by preventing foreign matter from entering the bearing (dynamic pressure bearing) 10 that supports the impeller 1. Can do.

  The curved portion 50 a of the strainer 50 has a curved cross section and is shaped so as to be smoothly connected to the wall surface of the volute chamber 2 a of the pump casing 2. Further, the distal end of the curved portion 50 a is disposed close to the outer peripheral surface of the impeller 1. That is, the strainer 50 extends from the wall surface of the volute chamber 2 a to the outer peripheral surface of the impeller 1, and the entire curved portion 50 a smoothly connects the wall surface of the volute chamber 2 a and the outer peripheral surface of the impeller 1. Most of the liquid discharged from the impeller 1 is rotated at high speed in the circumferential direction along the volute chamber 2a and the strainer 50 by centrifugal force, and the foreign matter once captured by the strainer 50 is washed away by the flow of the liquid. The liquid is discharged from the outlet 16a together with the liquid. Accordingly, the mesh of the strainer 50 is not easily clogged with foreign matter, and maintenance of the strainer 50 becomes unnecessary. Furthermore, since the curved portion 50a of the strainer 50 having the above-described shape constitutes an extension of the wall surface of the volute chamber 2a, the turbulent flow of liquid in the volute chamber 2a is suppressed, and the pump performance is improved.

  The motor pump described with reference to FIGS. 1 to 10 is a so-called end-top type motor pump in which the suction port and the discharge port are orthogonal to each other. However, the inline motor in which the suction port, the discharge port, and the impeller are arranged in a straight line. The present invention is also applicable to a pump.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 Impeller 2 Pump casing 3 Motor casing 5 Permanent magnet 6 Motor stator 10 Bearing 11 Rotation side bearing element 12 Fixed side bearing element 15 Suction port 15 Discharge port 20 Motor cover 30 Outer frame part 31 Inner frame part 32 Side wall part (partition wall) )
36 Rib 37 Return flow path 40 Cooling chamber 50 Strainer

Claims (7)

An impeller with a plurality of permanent magnets embedded therein;
A pump casing that houses the impeller;
A motor stator having a plurality of stator coils;
A motor casing that houses the motor stator;
A motor pump comprising a hydrodynamic bearing for supporting the impeller,
The dynamic pressure bearing and the motor stator are arranged on the suction side of the impeller,
The motor casing has a side wall portion located between the impeller and the stator coil, and a plurality of radially extending ribs, and the side wall portion is fixed to the plurality of ribs. Motor pump. In the motor casing, an accommodation space for accommodating the motor stator is formed,
The motor casing has an inner frame portion having an inner peripheral wall that forms the accommodating space, and an outer frame portion having an outer peripheral wall that forms the accommodating space,
The motor pump according to claim 1, wherein the plurality of ribs are fixed to the inner peripheral wall and the outer peripheral wall.   The at least 1 return flow path which returns the liquid discharged from the said impeller from the clearance gap between the said impeller and the said side wall part to the liquid inlet_port | entrance of the said impeller is provided. Motor pump.   The motor according to claim 1, wherein a motor cover made of metal is attached to the motor casing, and the motor cover is in contact with the motor stator. pump.   The motor pump according to claim 4, wherein a cooling chamber through which a coolant flows is attached to the motor cover.   The motor pump according to any one of claims 1 to 5, further comprising a strainer disposed between an outer peripheral surface of the impeller and an inner peripheral surface of the pump casing. The motor pump according to claim 6, wherein the strainer includes a curved portion having a shape that smoothly connects a wall surface of a volute chamber of the pump casing and an outer peripheral surface of the impeller.

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