Booster pump

Abstract

To provide a booster pump that can ease component accuracy regarding accuracy of gap dimension between an impeller and a housing accommodating the impeller, and is easily assembled.SOLUTION: A biasing member 13 is interposed between an axially inside end surface 12g of a pump housing 12 of a booster pump 1 and a first housing 12a, to constantly bias the first housing 12a toward a second housing 12b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a booster pump that is installed, for example, in a building where water pressure is low. [Background technology]

[0002] Cascade pumps, which are small and have high discharge pressure, are used in water supply facilities for apartment buildings, offices, schools, etc. Cascade pumps are pumps in which an impeller with many gear-like blades rotates at high speed inside a case with a concentric annular passage, drawing in water through an outer suction port connected to the annular passage, increasing the pressure as the pump rotates, and discharging the water from an outer discharge port connected to the annular passage.

[0003] The side channel pump described below has been proposed as an example of a cascade pump. This side channel pump includes an impeller that can rotate within a pump housing. The impeller is connected to a rotating shaft of an electric motor. The pump housing includes two housing sections held at a distance by a ring element and a casing. The ring element is sized so that the housing sections face the casing with a small gap between them and the end face of the impeller. The impeller has a ring-shaped passage section and an annular rotor chamber ring separated by guide vanes. The ring-shaped passage section, together with the rotor chamber, communicates from an inlet passage to an outlet passage, and forms a conveying chamber for conveying a medium when the impeller is driven to rotate (see Patent Document 1; JP-A-2010-509543). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2010-509543 Summary of the Invention [Problem to be solved by the invention]

[0005] The side channel pump of the above-mentioned Patent Document 1 requires a small gap (0.05 mm or less) between the impeller and the two housing parts held at a distance by the ring element. This requires dimensional accuracy between the two housing parts arranged to surround the impeller and the ring element, which leads to problems such as high manufacturing costs and difficult assembly work. [Means for solving the problem]

[0006] The present invention has been made to solve these problems, and its object is to provide a booster pump that improves the accuracy of the gap dimension between the impeller and the housing that houses it, allows the precision requirements for the housing components to be relaxed, and yet is easy to assemble.

[0007] In order to achieve the above object, the present invention has the following configuration. a pump housing in which a booster pump is provided, the pump housing having a first housing and a second housing overlapped on the radially outer side so that the impeller is rotatably accommodated between the first housing and the second housing, the pump housing having a booster flow passage along the outer circumferential edge of the impeller, and a suction flow passage and a discharge flow passage communicating with the booster flow passage via a partition wall; and a motor having a rotary shaft connected to an end of the impeller, a rotor connected to the rotary shaft, and a stator disposed opposite the rotor, Bottom plate that closes the and the first housing An urging member is interposed, and the urging member has a bottomed cylindrical portion at its center that fits into a recess in the first housing and accommodates the shaft end of the rotary shaft, and a disk portion that extends radially outward from the bottom of the bottomed cylindrical portion is sandwiched between the bottom plate and the first housing to constantly urge the first housing toward the second housing. It is characterized by:

[0008] In this way, the pump housing has the first and second housings directly overlapped on the radially outer side and the impeller rotatably accommodated between the first and second housings, so there is no need for a ring element between the first and second housings as in the prior art documents, and the number of parts is reduced, thereby improving the accuracy of the gap dimensions between the impeller and the first and second housings. Furthermore, because a biasing member that constantly biases the first housing toward the second housing is interposed between the axially inner end face of the pump casing and the first housing, there is no need to form the axially inner end face of the pump housing at an axial height that allows the first and second housings to be directly overlapped on the radially outer side, so the part accuracy requirements for the pump housing can be relaxed and assembly can be easily performed.

[0009] It is preferable that the biasing member has a bottomed cylindrical portion in the center that fits into a recess in the first housing and accommodates the axial end of the rotating shaft, and a disc portion that extends radially outward from the bottom of the bottomed cylindrical portion is sandwiched between the pump housing and the first housing. As a result, the bottomed cylindrical portion fits into the recess of the first housing, thereby preventing the biasing member from shifting in position. [Effects of the Invention]

[0010] To provide a booster pump in which the accuracy of the gap dimension between the impeller and the housing accommodating it can be adjusted regardless of the accuracy of the parts themselves and which can be easily assembled. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of a booster pump. [Figure 2] FIG. 2 is an enlarged cross-sectional view of a portion of FIG. [Figure 3] FIG. 3 is a horizontal cross-sectional view illustrating the configuration of the cascade pump of FIG. [Figure 4] 4A and 4B are a plan view, a right side view, and a perspective view of the biasing member of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a booster pump according to the present invention will be described below with reference to the accompanying drawings. First, the configuration of the booster pump 1 will be described with reference to Fig. 1. In the following, an example of the booster pump 1 will be a water supply pump connected to the water pipes of a condominium, apartment, or other multi-family dwelling. As shown in FIG. 1(B), the booster pump 1 is provided with a water inlet 3a to which a water pipe is connected on the side of the exterior cover 2, and a drain outlet 3b from which pressurized tap water is discharged.

[0013] The booster pump 1 contains the following components in a case body made up of a bottom plate 4 covered with an exterior cover 2. A cascade pump 5 is provided on the bottom plate 4. The cascade pump 5 is driven by a motor 6 provided on the top of the pump. Tap water pressurized by the cascade pump 5 is temporarily stored in an accumulator 7. This reduces instantaneous fluctuations in water pressure caused by pulsation and shocks of the tap water.

[0014] A self-cooling fan 8 is provided above the motor 6 to cool the heat generated by the motor coil of the stator. An intake port 10 for sending air into the self-cooling fan 8 is provided above the self-cooling fan 8. The electronic board 9 is equipped with a control unit (MPU) that controls the operation of the device, a ROM that stores the operating program, and a RAM that temporarily stores input / output data and reads the operating program and is used as a work area for the CPU. A display 11 is also provided on the top of the exterior cover 2. The display 11 is equipped with input keys and a display unit that displays input data and operating status.

[0015] The cascade pump 5 is equipped with an impeller 5a having a plurality of blades formed upright along the outer peripheral edge of a disk-shaped main plate and having blade grooves partitioned by the plurality of blades. The impeller 5a is attached near the axial end (lower end) of a rotating shaft 6a of a motor 6 by an impeller stopper 5b to prevent it from coming off in the axial direction. The motor 6 that drives the cascade pump 5 is equipped with a rotating shaft 6a to the axial end of which the impeller 5a is connected, a rotor 6b connected to the rotating shaft 6a, and a stator 6c disposed opposite to and surrounding the rotor 6b.

[0016] As shown in FIG. 2, a pump housing 12 is mounted on the bottom plate 4. Inside the pump housing 12, a first housing 12a and a second housing 12b are assembled by directly overlapping each other on the radially outer side. A ring element is not required between the first housing 12a and the second housing 12b as in the prior art document, and the number of parts is reduced, which improves the accuracy of the gap dimensions between the impeller 5a and the first and second housings 12a and 12b. Furthermore, the impeller 5a is rotatably accommodated between the first housing 12a and the second housing 12b with an extremely small gap (e.g., 0.05 mm or less) provided between them.

[0017] 3, the cascade pump 5 has a boost flow passage 12c along the outer peripheral edge of the impeller 5a, and a suction flow passage 12e and a discharge flow passage 12f that communicate with the boost flow passage 12c via a partition wall 12d, formed in the pump housing 12. The suction flow passage 12e communicates with the water supply port 3a, and the discharge flow passage 12f communicates with the accumulator 7 (see FIG. 1(A)).

[0018] A biasing member 13 is interposed between the axially inner end surface (lower end surface) 12g of the pump housing 12 and the first housing 12a. As shown in FIGS. 4(A) to 4(C), the biasing member 13 has a bottomed cylindrical portion 13a in its center that accommodates the axial end of the rotary shaft 6a. A disk portion 13b extending radially outward from the bottom of the bottomed cylindrical portion 13a is sandwiched between the pump housing 12 (lower end surface 12g) and the first housing 12a. The biasing member 13 is made of an elastic material such as fluororubber. The bottomed cylindrical portion 13a is hollow, and accommodates the axial end of the rotary shaft 6a and the impeller stopper 5b attached thereto. This prevents interference between the rotary shaft 6a and the biasing member 13 and does not affect the rotation of the impeller 5a. Furthermore, the bottomed cylindrical portion 13a fits into a recess 12h of the first housing 12a, preventing misalignment of the biasing member 13 (see FIG. 2). In this way, since the biasing member 13 constantly biases the first housing 12a toward the second housing 12b, there is no need to form the axially inner end face 12g of the pump housing 12 at an axial height that allows the first housing 12a and the second housing 12b to be directly overlapped on the radially outer side, so the component precision of the pump housing 12 can be relaxed and assembly work can be easily performed.

[0019] The rotary shaft 6a extending between the second housing 12b and the impeller 5a is provided with a mechanical seal 14. Specifically, one end of a cylindrical sliding member 14a fitted coaxially with the rotary shaft 6a is fixed to the second housing 12b. This mechanical seal 14 can prevent tap water from leaking from the pressurized flow path 12c to the rotary shaft 6a side.

[0020] The booster pump 1 described above can be applied not only to water supply facilities in apartment buildings and other collective housing, but also to water supply facilities in offices, schools, etc., and can improve the accuracy of the gap dimensions between the impeller and the pump housing that houses it, can relax the precision of the pump housing parts, and can provide a booster pump that is easy to assemble. [Explanation of symbols]

[0021] 1 booster pump 2 exterior cover 3a water inlet 3b drain port 4 bottom plate 5 cascade pump 5a impeller 5b impeller stopper 6 motor 6a rotating shaft 6b rotor 6c stator 7 accumulator 8 self-cooling fan 9 electronic board 10 heat dissipation rib 11 display 12 pump housing 12a first housing 12b second housing 12c booster flow path 12d partition wall 12e suction flow path 12f discharge flow path 12g axial inner end surface (lower end surface) 12h recess 13 biasing member 13a bottomed cylindrical portion 13b disc portion 14 mechanical seal 14a sliding member 14b coil spring

Claims

[Claim 1] an impeller having a plurality of blades formed along the outer periphery of a disk-shaped main plate; a pump housing in which a first housing and a second housing are overlapped on the radially outer side, the impeller is rotatably accommodated between the first housing and the second housing, and a pressure increase passage along an outer peripheral edge of the impeller, and a suction passage and a discharge passage communicating with the pressure increase passage via a partition wall, are formed; a motor including a rotary shaft having the impeller connected to an end thereof, a rotor connected to the rotary shaft, and a stator disposed opposite the rotor, a biasing member interposed between the first housing and a bottom plate that closes an axially inner end face of the pump housing, the biasing member having a bottomed cylindrical portion in its central portion that fits into a recess in the first housing and accommodates an axial end of the rotating shaft, and a disc portion extending radially outward from the bottom of the bottomed cylindrical portion is sandwiched between the bottom plate and the first housing to constantly bias the first housing toward the second housing.

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