Self-priming pump

Abstract

To provide a self-priming pump improved in assemblability.SOLUTION: A self-priming pump 1 includes an impeller 2, a motor 3 driving the impeller 2, and a casing 4 housing the impeller. The motor 3 includes: a stator 5; a stator mold 8 covering the stator 5 with a mold resin part 7; a rotor 10 formed to be integral with the impeller 2; and a shaft 11 supporting the rotor 10. The casing 4 includes: a casing body 32 provided with a volute 31 surrounding an outer periphery of the impeller 2; and a casing cover 36 which is joined to the casing body 32 and provided with a suction chamber 45 and a discharge chamber 46. A first shaft support part 16 supporting one end side of the shaft 11 is disposed on the stator mold 8 of the motor 3, and a second shaft support part 47 supporting the other end side of the shaft 11 is disposed on the casing cover 36 of the casing 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a self-priming pump. [Background technology]

[0002] This type of self-priming pump includes an impeller, an electric motor that drives the impeller, and a casing that houses the impeller. The electric motor includes a stator, a stator mold that covers the stator with a molded resin portion, a rotor that is integral with the impeller, and a shaft that supports the rotor. The casing includes a pump case that includes a volute that surrounds the outer periphery of the impeller, and a cover that is joined to the pump case and includes a suction chamber and a discharge chamber (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-118949 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned configuration, shaft support portions are arranged on both the stator block and the wall member that closes the side of the pump case, and since it is necessary to precisely position the shaft between the stator block, the case, and the wall member, there is a problem that assembly is difficult.

[0005] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a self-priming pump that can be easily assembled. [Means for solving the problem]

[0006] In order to solve the above problems, a self-priming pump according to an aspect of the present invention comprises an impeller, an electric motor that drives the impeller, and a casing that houses the impeller, wherein the electric motor has a stator, a stator mold that covers the stator with a molded resin portion, a rotor that is formed integrally with the impeller, and a shaft that supports the rotor, and the casing has a casing body that has a volute that surrounds the outer periphery of the impeller, and a casing cover that is joined to the casing body and has a suction chamber and a discharge chamber, and the casing cover has a wall portion that defines the suction chamber and the discharge chamber, and a return passage that connects the discharge chamber and the suction chamber, and the return passage is provided in the wall portion. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a self-priming pump that can improve assembly efficiency. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side cross-sectional view of a self-priming pump according to an embodiment. [Figure 2] FIG. 1 is an exploded perspective view of a self-priming pump according to an embodiment. [Figure 3] FIG. [Figure 4] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present embodiment will be described in detail below with reference to the drawings.

[0010] The self-priming pump according to this embodiment can be used as a circulation pump in a hot water supply device or a heating device, or as a water supply pump in a dishwasher or a washing machine.

[0011] 1 and 2, the self-priming pump 1 includes an impeller 2, an electric motor 3 that drives the impeller 2, and a casing 4 that houses the impeller 2. In this embodiment, the left side in FIG. 1 is referred to as the "front side" or "front surface," and the right side in FIG. 1 is referred to as the "rear side" or "rear surface."

[0012] The impeller 2 has a plurality of blades 2a arranged at intervals around the circumferential direction of the impeller 2, a front shroud 2b covering one end side (front end side) of the blades 2a, and a rear shroud 2c covering the other end side (rear end side) of the blades 2a.

[0013] The electric motor 3 has a stator 5 for driving the impeller 2 to rotate, and a stator mold 8 that covers the stator 5 and a control board 6 with a molded resin part 7. The electric motor 3 also has a rotor 10 formed integrally with the impeller 2, and a shaft 11 that supports the rotor 10.

[0014] The stator mold 8 has a stator core 12 formed by stacking multiple metal plates, an insulating plate 13 covering the stator core 12, a stator 5 formed by winding a coil 14 around the insulating plate 13, and a control board 6 that controls the current flowing through the coil 14.

[0015] Additionally, a cylindrical first shaft support portion (boss) 16 that supports one end side (rear end side) of the shaft 11 of the impeller 2 is disposed in the stator mold 8. In this embodiment, a separation plate 15 is disposed on the inner surface of the molded resin portion 7, and the first shaft support portion 16 is molded integrally with this separation plate 15. Note that the separation plate 15 and the first shaft support portion 16 are molded separately from the molded resin portion 7, but at least the first shaft support portion 16 may be resin molded integrally with the molded resin portion 7.

[0016] The rotor 10 has a cylindrical magnet 17 arranged on the inner periphery of the stator 5, a magnet cover 18 that covers the outer periphery of the magnet 17, and a molded resin part 20 that covers the inner periphery of the magnet 17. The magnet cover 18 is molded from resin separately from the molded resin part 20. The rotor 10 (molded resin part 20) is connected to the impeller 2 (rear shroud 2c) via a neck part (connection part) 9. The rotor 10 is supported by a shaft 11 via a bearing 21, so that the rotor 10 and the impeller 2 can rotate around the shaft 11 as the center of rotation.

[0017] 1 to 3, the casing 4 has a casing body 32 equipped with a volute 31 that surrounds the outer periphery of the impeller 2. The separation plate 15 of the stator mold 8 is joined to the rear surface (right side in FIG. 1) of the casing body 32 with an O-ring 33 interposed therebetween.

[0018] On the other hand, a casing cover 36 is joined to the front surface (left side in FIG. 1) of the casing body 32 opposite the stator mold 8, with a partition plate 34 and a packing (plate-shaped sealing material) 35 interposed therebetween. In other words, the partition plate 34 and the packing 35 are interposed between the casing body 32 and the casing cover 36.

[0019] 3, the casing cover 36 has an intake port 41, an exhaust port 42, a drain port 43, and a return passage 44 from a discharge chamber 46 (described later) to the suction chamber 45. The casing cover 36 is joined to the front surface of the casing body 32 opposite the stator mold 8 side with the partition plate 34 and the packing 35 interposed therebetween, thereby forming the suction chamber 45 and the discharge chamber 46 between the casing cover 36 and the partition plate 34.

[0020] Additionally, a cylindrical second shaft support portion (boss) 47 is disposed on the casing cover 36 to support the other end (front end) of the shaft 11 of the impeller 2. This second shaft support portion 47 passes through a suction hole 53 (described later) in the installed state, and further extends toward the first shaft support portion 16.

[0021] The casing cover 36 is provided with a straight wall portion 48 and a curved wall portion 49 for partitioning the suction chamber 45 and the discharge chamber 46. The curved wall portion 49 is formed concentrically with the second shaft support portion 47 on the outer circumferential side of the second shaft support portion 47.

[0022] Incidentally, if the second shaft support portion 47 is provided on the casing cover 36, the flow Fa of water flowing from the return passage 44 into the suction chamber 45 may collide with the second shaft support portion 47, possibly generating noise. Therefore, as shown in Figure 4, the return passage 44 is formed in a position where an extension line of the flow Fa of water flowing from the return passage 44 into the suction chamber 45 does not overlap with the second shaft support portion 47. In other words, the return passage 44 is formed in the curved wall portion 49 so that an extension line from the periphery of the return passage 44 does not overlap with the second shaft support portion 47.

[0023] Furthermore, the return passage 44 is formed in a direction along the water flow Fb toward the impeller 2 in the suction chamber 45. That is, the return passage 44 is formed in the curved wall portion 49 so as to be inclined from the upstream side toward the downstream side of the water flow Fb in the suction chamber 45.

[0024] Furthermore, the return passage 44 is formed at a position farthest from the end of the casing cover 36 where the discharge port 42 is located. That is, the return passage 44 is formed in the curved wall portion 49 so as to face the discharge port 42 with the second shaft support portion 47 therebetween.

[0025] As shown in FIG. 2, the casing cover 36 is provided with a plurality of bosses 51 (four in this embodiment) for engaging with the separation plate 15 of the stator mold 8, and the casing main body 32 is provided with insertion portions 52 through which the bosses 51 of the casing cover 36 are inserted.

[0026] The stator mold 8 (electric motor 3), casing body 32, and casing cover 36 are fixed together using screws (not shown).

[0027] 1 and 2, the partition plate 34 and the packing 35 are overlapped and integrated to close the front surface of the casing body 32 on the casing cover 36 side. The partition plate 34 is formed with a suction hole 53, a discharge hole 54, and a return hole 55 for self-priming.

[0028] The suction hole 53 of the partition plate 34 is formed in the center of the partition plate 34 when installed. The suction hole 53 communicates the suction chamber 45 formed between the casing cover 36 and the partition plate 34 with the inlet of the impeller 2 disposed inside the casing body 32.

[0029] Discharge hole 54 of partition plate 34 is formed in the upper end portion of partition plate 34 in the installed state. Discharge hole 54 communicates between the outlet of volute 31 formed in casing body 32 and discharge chamber 46 formed between casing cover 36 and partition plate 34.

[0030] The return hole 55 of the partition plate 34 is formed in the lower end portion of the partition plate 34 in the installed state. The return hole 55 communicates the discharge chamber 46 formed between the casing cover 36 and the partition plate 34 with the inside of the volute 31 formed in the casing body 32.

[0031] The operation of the self-priming pump 1 configured as above will now be described.

[0032] The self-priming pump 1 operates in a self-priming mode, in which water is drawn up from an external water tank (not shown) when there is gas in the volute 31 and piping, and a normal operating mode, in which water is discharged to the outside when the volute 31 and piping are full of water (only water, no gas).

[0033] First, the water tank and the suction port 41 of the self-priming pump 1 are connected by piping (suction piping), then piping (discharge piping) is connected to the discharge port 42 of the self-priming pump 1, and further piping (drain piping) is connected to the drain port 43 of the self-priming pump 1.

[0034] Next, after water is poured into the interior of the self-priming pump 1 (inside the volute 31), the control board 6 is energized, and a rotating magnetic field is generated from the stator 5, causing the rotor 10 and the impeller 2 to rotate.

[0035] Water is pressurized by centrifugal force generated by the rotation of the impeller 2, passes through the discharge hole 54 of the partition plate 34 along the volute 31, and is sent to the discharge chamber 46 on the casing cover 36 side.

[0036] When the water in the volute 31 is sent to the discharge chamber 46 , negative pressure is created inside the impeller 2 , and the water and gas pass through the suction port 41 , the suction chamber 45 , and the suction hole 53 and are sent into the volute 31 .

[0037] In the self-priming mode, the water sent from the volute 31 to the discharge chamber 46 passes through the return hole 55 or return passage 44 at the lower end of the self-priming pump 1 when installed and returns to the volute 31, so that only gas is sent from the discharge chamber 46 to the discharge port 42.

[0038] As a result, only the gas remaining in the volute 31 is gradually discharged from the discharge port 42 into the piping, causing the water in the water tank to be sucked up by the self-priming pump 1, and the volute 31 and the piping become filled with water.

[0039] Once the volute 31 and the piping are filled with water, the self-priming mode is changed to the normal operation mode in which only water is discharged from the discharge port 42 into the piping.

[0040] In normal operation mode, the water sent to the discharge chamber 46 flows separately into two parts: water that is discharged from the discharge port 42 into the piping, and water that passes through the return hole 55 and is returned to the volute 31, or water that passes through the return passage 44 and is returned from the suction chamber 45 to the volute 31.

[0041] When the water inside the self-priming pump 1 is drained, the water inside the volute 31 passes through the return hole 55 at the lower end of the self-priming pump 1 in the installed state and is discharged from the drain port 43.

[0042] The effects of this embodiment will be described below.

[0043] (1) Self-priming pump 1 includes impeller 2, electric motor 3 that drives impeller 2, and casing 4 that houses impeller 2. Electric motor 3 includes stator 5, stator mold 8 that covers stator 5 with molded resin portion 7, rotor 10 that is formed integrally with impeller 2, and shaft 11 that supports rotor 10. Casing 4 includes casing body 32 that includes volute 31 that surrounds the outer periphery of impeller 2, and casing cover 36 that is joined to casing body 32 and includes suction chamber 45 and discharge chamber 46. A first shaft support portion 16 that supports one end of shaft 11 is disposed in stator mold 8 of electric motor 3, and a second shaft support portion 47 that supports the other end of shaft 11 is disposed in casing cover 36 of casing 4.

[0044] According to such a self-priming pump 1, the shaft 11 is positioned between the stator mold 8 of the electric motor 3 and the casing cover 36 of the casing 4, which makes it possible to improve the assembly ease of the self-priming pump 1.

[0045] Furthermore, with the self-priming pump 1, it is possible to reduce variations in the position of the shaft 11 compared to when the shaft 11 is positioned mutually between the stator mold 8 of the motor 3, the casing body 32, and the partition plate 34.

[0046] (2) The casing cover 36 has a return passage 44 that connects the discharge chamber 46 and the suction chamber 45. The return passage 44 is formed at a position where an extension line of the flow Fa of water flowing from the return passage 44 into the suction chamber 45 does not overlap with the second shaft support portion 47.

[0047] By configuring the return passage 44 in this manner, the flow of water Fa flowing from the return passage 44 into the suction chamber 45 is prevented from colliding with the second shaft support portion 47, thereby making it possible to suppress the generation of noise within the casing cover 36.

[0048] (3) The return passage 44 is formed in a direction along the water flow Fb to the impeller 2.

[0049] By configuring the return passage 44 in this manner, it is possible to avoid collision (interference) between the water flow Fa flowing from the return passage 44 into the suction chamber 45 and the water flow Fb heading towards the impeller 2 within the suction chamber 45, thereby suppressing the generation of noise.

[0050] (4) The return passage 44 is formed at a position furthest from the end of the casing cover 36 where the discharge port 42 is located.

[0051] By configuring the return passage 44 in this manner, it is possible to reduce the impact on the flow of water flowing near the discharge port 42 and to suppress the decline in flow rate-head characteristics (performance curve) due to the placement of the return passage 44 in the suction chamber 45.

[0052] As a result of measurements conducted in an experiment, when the return passage 44 is provided as in this embodiment, noise is reduced by 5.8 dB (A) compared to when the return passage 44 is provided in a conventional position where the extension line of the water flow Fa flowing into the suction chamber 45 overlaps with the second shaft support portion 47.

[0053] The above-described embodiment is an example of the present disclosure, and therefore the present disclosure is not limited to the above-described embodiment, and various modifications can be made to the present disclosure depending on the design, etc., as long as they do not deviate from the technical concept of the present disclosure. [Explanation of symbols]

[0054] 1 Self-priming pump 2 impellers 3 Electric motor 4 Casing 5 Stator 7 Molded resin part 8 Stator mold 10 rotors 11 axes 16 First shaft support part 31 Volute 32 Casing body 36 Casing cover 42 Discharge port 44 Reflux passage 45 Intake chamber 46 Discharge chamber 47 Second shaft support part

Claims

1. An impeller and an electric motor that drives the impeller; a casing that houses the impeller, The electric motor is a stator; a stator mold that covers the stator with a molded resin portion; a rotor formed integrally with the impeller; a shaft supporting the rotor, The casing comprises: a casing body including a volute surrounding the outer periphery of the impeller; a casing cover joined to the casing body and including a suction chamber and a discharge chamber; The casing cover is a curved wall portion that defines the suction chamber and the discharge chamber; a return passage communicating the discharge chamber with the suction chamber, the return passage is provided in the curved wall portion, a shaft support portion that supports one end of the shaft is disposed on the casing cover of the casing, The return passage is formed by cutting out the curved wall portion, which is formed concentrically with the shaft support portion on the outer circumferential side of the shaft support portion, at a position where the direction of water flow from the discharge chamber to the suction chamber does not overlap with the shaft support portion. Self-priming pump.

2. 2. The self-priming pump according to claim 1, wherein the return passage is formed in a direction along the flow of water to the impeller.

3. 3. The self-priming pump according to claim 1, wherein the return passage is formed at a position furthest from an end of the casing cover where the discharge port is located.

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