Submersible pump

Abstract

To provide a submerged pump which prevents over-fastening of fastening components to a waterproof cover for watertightly sealing a motor case, is easily assembled by just adjusting a thread fastening quantity, and is improved in waterproofness.SOLUTION: A pump case 2 of a motor case 3 is assembled by overlapping a waterproof cover 5 and a back cover 6 at an axial opening end on an opposite side. A motor base plate 3m electrically connected to a stator 3B is housed in an internal space of the motor case 3 closed by the waterproof cover 5 and the back cover 6. A lead wire 3p connected to the motor base plate 3m penetrates the back cover 6 by inserting a tube-like lead wire taking-out port 5f formed integrally with the waterproof cover 5, and is taken out to the outside of the motor case 3.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a submersible pump that is placed, for example, in the water tank of a flush toilet to flush the toilet bowl, or in flooded water to drain water. [Background technology]

[0002] The pump body case contains a motor, an impeller driven by the motor, and a water passage surrounding the impeller. Water is drawn in through the suction port, pressure-fed by the rotating impeller, and discharged from the discharge port. The motor is surrounded by a waterproof cover made of rubber or vinyl chloride, and the waterproof cover is attached to the pump body case by overlapping its flange and threading it with multiple screws to maintain a watertight seal. The waterproof cover also has an extended tubular section through which an electrical cord passes. A stainless steel clamping ring is fitted into this tubular section, and the tubular section is crimped onto the electrical cord to maintain a watertight seal (Patent Document 1; Utility Model Publication No. 14322 / 1976). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Jikko No. 51-14322 Summary of the Invention [Problem to be solved by the invention]

[0004] When tightening the waterproof cover of the aforementioned Patent Document 1 to the case of the pump body with screws, the worker must carefully control the amount of tightening of the screws. If the screws are tightened too much, the waterproof cover made of rubber or resin is prone to bending, which can cause gaps to form and allow water to seep in. Furthermore, if the screws are not tightened properly, there is a risk of water seeping in through gaps that form between the waterproof cover and the case. The same applies to the metal tightening ring fitted into the tubular part of the waterproof cover where the electrical cord comes out. [Means for solving the problem]

[0005] The present invention has been made to solve these problems, and its purpose is to provide an underwater pump that is easy to assemble and has improved waterproofing by preventing overtightening of the fastening parts on the waterproof cover that seals the motor case watertight, and by adjusting the amount of screw tightening so that it is neither too tight nor too tight.

[0006] In order to achieve the above object, the present invention has the following configuration. a pump section including an impeller having an inlet port in the center of a pump case for sucking stored water and an outlet port on the outer periphery of the pump case for discharging a pressurized water flow into the pump case, the impeller pressurizing the stored water sucked into the pump case from the inlet port and discharging it from the outlet section; a rotor housed in a cylindrical motor case assembled to the pump case, with rotor poles arranged concentrically around the rotor shaft; and a stator having stator poles arranged opposite to the rotor poles, the drive section having one end side of the rotor shaft housed in the motor case extending toward the pump case to serve as the rotating shaft of the impeller, the waterproof cover and back cover being assembled together in an overlapping manner to the axial opening end of the motor case on the opposite side to the pump case, the motor case being closed by the waterproof cover and the back cover and housing a motor board electrically connected to the stator in its internal space, and a tubular lead wire outlet through which lead wires connected to the motor board are inserted penetrates the back cover and is formed integrally with the waterproof cover, The pump case, the motor case, and the back cover are fixed with screws at a plurality of locations in the circumferential direction in a state where a water-stopping protrusion protruding from the opening end of the waterproof cover in the axial direction is pressed against the opposing opening end of the motor case, and a cover protrusion protruding from the opening end of the back cover is abutted against the opening end of the motor case exposed from the waterproof cover in the axial direction. It is characterized by the following. In this way, the waterproof cover and back cover are assembled together at the axial opening end of the cylindrical motor case opposite the pump case, thereby improving the waterproofness of the motor case. The lead wires connected to the motor board are inserted through the tubular lead wire outlet formed integrally with the waterproof cover and passed through the back cover to be taken out, and the lead wire outlet can be easily crimped and closed, preventing a decrease in waterproofness due to overtightening of the waterproof cover's fastening parts. Furthermore, because the waterproof cover and back cover are assembled to the open end of the cylindrical motor case by overlapping them in the axial direction, the back cover can be used to crush the waterproof cover's watertight protrusions, improving the waterproofness of the motor case. In particular, because the pump case, motor case, and back cover are fixed with screws at multiple locations around the circumference with the cover protrusions abutting against the axial open end of the motor case exposed by the waterproof cover, there is no variation in the amount of tightening, such as the screws being tightened too tightly or too loosely, depending on the worker, and assembly can be performed without variation in the amount of crushing of the watertight protrusions.

[0007] It is preferable that a waterproof case is integrally assembled between the pump case and the motor case, covering the rotor and separating it from the stator, and that the stator and motor board are housed inside the cylindrical motor case, whose openings on both sides are closed by the waterproof case and the waterproof cover. This allows the rotor and stator to be separated and positioned within the motor case by the waterproof case, improving the watertightness of the electrical components housed within the cylindrical motor case, whose openings on both sides are closed by the waterproof case and waterproof cover.

[0009] A first flange portion and a second flange portion may be provided at the open end of the motor case from the radially inner side to the radially outer side, with a step interposed between them, and the waterproof cover may be provided with a sealing portion in which a water-stopping protrusion pressed against the first flange portion and a sealing protrusion pressed against the second flange portion are provided in series with a circumferential groove. As a result, when the pump case, motor case, and back cover are screwed together, the watertight protrusions pressed against the first flange are crushed to fill the circumferential groove, and the sealing protrusions connected to the watertight protrusions are pressed against the second flange connected to the first flange via a step. Therefore, the deformation of the watertight protrusions of the waterproof cover and the labyrinth structure of the sealing protrusions connected to them improve the waterproofness of the motor case.

[0010] It is preferable that a plurality of through holes are drilled in the second flange portion of the motor case, the sealing portion of the waterproof cover is provided with enlarged through holes that communicate with the through holes and that enlarge radially outward from each through hole, the back cover is provided with screw holes that communicate with the through holes and the enlarged through holes in a fixing portion that is superimposed on the sealing portion, the enlarged through holes and screw holes are aligned with the through holes of the motor case so that the sealing portion and the fixing portion are superimposed on the second flange portion, and the cover protrusions that protrude from the fixing portion along the outer peripheral edge of the enlarged through holes are each abutted against the second flange portion exposed from the enlarged through holes. As a result, when the pump case, motor case, and back cover are screwed together, the cover protrusions protruding from the fixing portion along the outer edge of the enlarged through hole each abut against the second flange portion exposed from the enlarged through hole, so there is no variation in the amount of screw tightening, and the outer periphery of the cover protrusion can be surrounded by the sealing protrusion, improving the waterproofness of the motor case. [Effects of the Invention]

[0011] To provide a submersible pump that is easy to assemble and has improved waterproofing by preventing overtightening of fastening parts for a waterproof cover that seals a motor case watertight and by adjusting the amount of screw tightening to the right degree. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a plan view of a submersible pump. [Figure 2] FIG. 2 is a front view of the submersible pump of FIG. [Figure 3] FIG. 3 is a right side view of the submersible pump of FIG. [Figure 4] FIG. 4 is a rear view of the submersible pump of FIG. [Figure 5] FIG. 5 is a perspective view of the submersible pump of FIG. [Figure 6] FIG. 6 is a bottom view of the submersible pump of FIG. 5 as seen from the suction port. [Figure 7] 7 is a cross-sectional view of the submersible pump of FIG. 2 taken along the arrow AA. [Figure 8] 8 is a cross-sectional view of the submersible pump of FIG. 2 taken along the arrow BB. [Figure 9] FIG. 9 is a cross-sectional view of the submersible pump in the direction of arrow CC in FIG. [Figure 10] FIG. 10 is an enlarged cross-sectional view of a portion of the submersible pump of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of a submersible pump according to the present invention will now be described with reference to the accompanying drawings. First, the configuration of a submersible pump 1 will be described with reference to FIGS. The submersible pump 1 is assembled integrally by stacking the motor case 3 in the axial direction via the pump case 2 and waterproof case 4, and then stacking the waterproof cover 5 and back cover 6 on the motor case 3 in that order, and threading the sleeve bolts 7 provided at four locations circumferentially.

[0014] A suction port 2a that draws in stored water is protruded from the center of the pump case 2. A discharge port 2b that discharges pressurized water is provided on the outer periphery of the pump case 2. An impeller 2c is rotatably housed within the pump case 2 (pump section; see Figure 6). When the impeller 2c rotates, stored water is sucked into the pump case 2 through the suction port 2a, pressurized by the impeller 2c, and discharged from the discharge port 2.

[0015] 8, a waterproof case 4 that covers the rotor 3A and separates it from the stator 3B is integrally assembled between the pump case 2 and the motor case 3. The stator 3B is assembled inside the motor case 3 separated by the waterproof case 4, and a motor board 3m that is electrically connected to the stator 3B is housed inside a back cover 6 assembled to the motor case 3. As a result, the rotor 3A and the stator 3B are separated and arranged by the waterproof case 4 within the motor case 3, thereby improving the watertightness of the electrical components housed within the cylindrical motor case 3, whose openings on both sides are closed by the waterproof case 4 and the waterproof cover 5.

[0016] A rotor 3A is housed inside the waterproof case 4. The rotor 3A has a rotor yoke 3e and a rotor magnet 3f (rotor magnetic poles) concentrically arranged around a rotor shaft 3c via a bearing 3d. The rotor magnet 3f has N and S poles formed alternately in the circumferential direction. One end of the rotor shaft 3c extends toward the pump case 2 and serves as the rotation shaft of the impeller 2c. The other end of the rotor shaft 3c is supported by a waterproof case 4 that is nested within the motor case 3. In this way, the rotor 3A and the stator 3B are separated and arranged by the waterproof case 4 within the motor case 3, thereby improving the watertightness of the stator 3B and electrical components such as the motor board 3m electrically connected to it. The rotor yoke 3e and impeller 2c may be formed integrally as shown in FIG. 8, or may be assembled separately.

[0017] Additionally, a cylindrical motor case 3 is assembled to the waterproof case 4, overlapping them in the axial direction. A stator 3B is assembled to the motor case 3. Specifically, an annular core back portion 3h of a stator core 3g is adhesively fixed to the inner wall surface of the motor case 3. Pole teeth (teeth) 3i extending radially inward from the back yoke 3h are wound with motor coils 3k via insulators 3j. The magnetic flux acting surfaces of the pole teeth 3i are arranged opposite the rotor magnet 3f via the waterproof case 4 (see FIG. 7). Furthermore, a motor board 3m (drive unit; see FIG. 8) on which a current-carrying circuit for passing current to the motor coil 3k is formed is held by the insulator 3j.

[0018] As shown in Fig. 8, a waterproof cover 5 and a back cover 6 are attached to the open axial end of the motor case 3 on the opposite side from the pump case 2. A motor board 3m electrically connected to the stator 3B is housed in the internal space of the motor case 3 closed by the waterproof cover 5 and the back cover 6. As shown in Fig. 9, a tubular lead wire outlet 5f, through which lead wires 3p connected to the motor board 3m are inserted, penetrates the back cover 6 and is formed integrally with the waterproof cover 5. Because the lead wire outlet 5f penetrates the back cover 6 and extends to the outside, the lead wires 3p connected to the motor board 3m are inserted through the lead wire outlet 5f and drawn out to the outside of the motor case 3.

[0019] In this way, the waterproof cover 5 and back cover 6 are assembled together in an overlapping manner to the axial opening end of the cylindrical motor case 3 opposite the pump case 2, thereby improving the waterproofness of the motor case 3. The lead wires 3p connected to the motor board 3m are inserted through the tubular lead wire outlet 5f formed integrally with the waterproof cover 5 and taken out through the back cover 6, so the lead wire outlet 5f can be easily crimped to the lead wires 3p and closed easily with an adhesive or the like, preventing a decrease in waterproofness due to overtightening of the fastening parts of the waterproof cover 5. As described above, the space at the other axial end of the motor is highly watertight, so electrical systems and wiring mechanisms such as the motor board 3m can be installed without worrying about water intrusion.

[0020] 10, a first flange portion 3b1 and a second flange portion 3b2 are connected with a step from the radially inner side to the radially outer side at the open end on the other axial end side of the motor case 3. The waterproof cover 5 is provided with a seal portion 5a in which a water-stopping protrusion 5c pressed against the first flange portion 3b1 and a seal protrusion 5d pressed against the second flange portion 3b2 are connected via a circumferential groove 5e. 10, when the pump case 2, motor case 3, and back cover 6 are screwed together, the watertight protrusions 5c pressed against the first flange portion 3b1 are crushed to fill the circumferential groove 5e, and the sealing protrusions 5d connected to the watertight protrusions 5c are pressed against the second flange portion 3b2 connected to the first flange portion 3b1 via a step. Therefore, the deformation of the watertight protrusions 5c of the waterproof cover 5 and the labyrinth structure of the sealing protrusions 5d connected to them improve the waterproofness of the motor case 3.

[0021] As shown in Fig. 7, a plurality of (for example, four) through holes 3n are drilled in the circumferential direction in the second flange portion 3b2 of the motor case 3. Enlarged through holes 5b that communicate with the through holes 3n and that enlarge radially outward from each of the through holes 3n are provided in the sealing portion 5a of the waterproof cover 5. As shown in Fig. 8, the back cover 6 has a fixing portion 6a that is superimposed on the sealing portion 5a and is provided with screw holes 6b that communicate with the through holes 3n and the enlarged through holes 5b.

[0022] 10, the waterproof cover 5 and the back cover 6 are overlapped with the enlarged through hole 5b and the screw holes 6b aligned with the through hole 3n of the motor case 3. At this time, the cover projections 6c projecting from the fixing portion 6a along the outer periphery of the enlarged through hole 5b are respectively abutted against the second flange portion 3b2 exposed from the enlarged through hole 5b. Annular seal projections 5d that fit into stepped portions 3b3 provided in the second flange portion 3b2 are provided on the radially outer and inner sides of the enlarged through hole 5b provided in the seal portion 5a.

[0023] As a result, when the pump case 2, motor case 3 and back cover 6 are screwed together, the water-stopping protrusion 5c is pressed against the first flange portion 3b1, and the cover protrusions 6c protruding from the fixing portion 6a along the outer peripheral edge of the enlarged through hole 5b are respectively pressed against the second flange portion 3b2 exposed from the enlarged through hole 5b, so there is no variation in the amount of screw tightening, and the outer peripheral side of the cover protrusion 6c can be surrounded by the sealing protrusion 5d, thereby improving the waterproofness of the motor case 3.

[0024] As shown in FIG. 10, a threaded hole 6b provided in the back cover 6 is provided with a thread groove, into which a threaded portion 7a provided at the tip of the sleeve bolt 7 is threadably fitted. The waterproof cover 5 and back cover 6 are superimposed on the motor case 3 with the through hole 3n, the enlarged through hole 5b, and the screw hole 6a aligned with each other, and at the peripheral portion of the through hole 3n of the second flange portion 3b2, the cover protrusions 6c are surrounded on the outer periphery by the seal protrusions 5d and are respectively abutted against the second flange portion 3b2 exposed from the enlarged through hole 5b and are screwed into place by the sleeve bolts 7.

[0025] In this way, the waterproof cover 5 and back cover 6 are assembled to the axially open end of the motor case 3 by overlapping them in the axial direction. The back cover 6 compresses the waterproof cover 5 (waterstop protrusion 5c) during assembly, improving waterproofing. In particular, the pump case 2, motor case 3, and back cover 6 are fastened with screws at multiple locations around the circumference, with the cover protrusion 6c abutting against the axially open end of the motor case 3 exposed by the waterproof cover 5. This prevents variations in the tightening amount (e.g., tightening the screws too tightly or too loosely) between workers, and allows assembly without variations in the amount of compression of the waterstop protrusion 5c. Furthermore, the deformation of the waterstop protrusion 5c of the waterproof cover 5 and the labyrinth structure of the sealing protrusion 5d connected thereto improve the waterproofing of the motor case 3. Furthermore, the sealing protrusion 5d surrounds the outer periphery of the cover protrusion 6c, which abuts against the second flange portion 3b2 exposed from the enlarged through-hole 5b, thereby improving the waterproofing of the motor case 3.

[0026] The above-described submersible pump 1 is expected to be used underwater, for example, in flush toilet water tanks or drainage pumps, and a highly reliable submersible pump 1 can be provided without compromising the waterproofness of the drive unit. [Explanation of symbols]

[0027] 1 Submersible pump 2 Pump case 2a Suction port 2b Discharge port 2c Impeller 3 Motor case 3A Rotor 3B Stator 3 Motor case 3b1 First flange portion 3b2 Second flange portion 3b3 Stepped portion 3c Rotor shaft 3d Bearing 3e Rotor yoke 3f Rotor magnet 3g Stator core 3h Core back portion 3i Pole teeth 3j Insulator 3k Motor coil 3m Motor board 3n Through hole 3p Lead wire 4 Waterproof case 5 Waterproof cover 5a Seal portion 5b Enlarged through hole 5c Watertight protrusion 5d Seal protrusion 5e Circumferential groove 5f Lead wire outlet 6 Back cover 6a Fixing portion 6b Screw hole 6c Cover protrusion 7 Sleeve bolt 7a Threaded portion

Claims

1. An underwater pump comprising: a pump section having an inlet port in the center of a pump case for sucking stored water; and an impeller having an outlet port on the outer periphery of the pump case for discharging pressurized water; the impeller pressurizing the stored water drawn into the pump case from the inlet port and discharging it from the outlet section; a rotor housed in a cylindrical motor case assembled to the pump case, with rotor poles concentrically arranged around the rotor shaft; and a drive section having a stator with stator poles arranged opposite the rotor poles, wherein one end of the rotor shaft housed in the motor case extends toward the pump case and serves as the rotating shaft of the impeller; a waterproof cover and a back cover are assembled together by overlapping them at an axial opening end of the motor case on the opposite side to the pump case, a motor board electrically connected to the stator is housed in an internal space of the motor case closed by the waterproof cover and the back cover, and a tubular lead wire outlet through which lead wires connected to the motor board are inserted penetrates the back cover and is formed integrally with the waterproof cover, a water-stopping protrusion protruding from the open end of the waterproof cover in the axial direction is pressed against the opposing open end of the motor case, and a cover protrusion protruding from the open end of the back cover is abutted against the open end of the motor case exposed from the waterproof cover in the axial direction; and the pump case, the motor case, and the back cover are fixed with screws at multiple locations in the circumferential direction.

2. An underwater pump as described in claim 1, wherein a waterproof case is integrally assembled between the pump case and the motor case, covering the rotor and separating it from the stator, and the stator and motor board are housed inside the cylindrical motor case, whose both side openings are closed by the waterproof case and the waterproof cover.

3. 3. An underwater pump according to claim 1, wherein a first flange portion and a second flange portion are connected via a step at the open end of the motor case from the radially inner side to the radially outer side, and the waterproof cover is provided with a sealing portion in which a water-stopping protrusion pressed against the first flange portion and a sealing protrusion pressed against the second flange portion are connected via a circumferential groove.

4. a second flange portion of the motor case having a plurality of through holes drilled in a circumferential direction; the seal portion of the waterproof cover having enlarged through holes that communicate with the through holes and that enlarge radially outward from the through holes; and a fixing portion of the back cover that is superimposed on the seal portion has screw holes that communicate with the through holes and the enlarged through holes, The underwater pump according to claim 3, wherein the waterproof cover portion and the back cover are superimposed with the enlarged through hole and the screw hole aligned with the through hole of the motor case, and the cover protrusions protruding from the fixing portion along the outer peripheral edge of the enlarged through hole are respectively abutted against the second flange portion exposed from the enlarged through hole.

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