Booster pump

Abstract

[Problem] To provide a booster pump in which the precision of the size of a gap between an impeller and a housing that accommodates the impeller can be reduced, and which is easy to assemble. A biasing member (13) for constantly biasing a first casing (12a) to a second casing (12b) is interposed between an axial inner end surface (12g) of a pump casing (12) of a booster pump (1) and the first casing (12a).

Description

Technical Field

[0001] The present disclosure relates to a booster pump, for example, arranged in a building where the water pipe pressure is low. Background Art

[0002] Small-sized cascade pumps with high discharge pressure are used in water supply facilities in residential buildings, office buildings, schools, etc. A cascade pump is a pump in which an impeller having multiple blades similar to a gear rotates at high speed in a casing having an annular channel formed concentrically, sucks in water from an outer peripheral side suction port connected to the annular channel, and discharges water from an outer peripheral side discharge port connected to the annular channel after the pressure is increased during rotation.

[0003] As an example of a cascade pump, the following side channel pump is proposed. The side channel pump includes an impeller that can rotate in a pump housing. The impeller is connected to the rotating shaft of the motor. The pump housing includes two housing parts and a shell that are held at a distance by an annular element. The annular element has such a size that the housing part is slightly spaced from the end face of the impeller and is opposite to the shell. The impeller has a ring-shaped rotor chamber separated by guide blades in the annular channel part. The annular channel part and the rotor chamber together lead from the inlet channel to the outlet channel, forming a conveying chamber for conveying the medium when the impeller is driven to rotate (see Patent Document 1; Japanese Patent Publication No. 2010-509543). Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Publication No. 2010-509543 Summary of the invention Technical problem to be solved by the invention

[0005] The side channel pump of Patent Document 1 needs to reduce the gap between the impeller and the two housing parts held at a distance by the annular element (to 0.05 mm or less). Therefore, the dimensional accuracy of the two housing parts and the annular element arranged to surround the impeller is required, which leads to problems such as high manufacturing cost and difficult assembly work. Means for solving technical problems

[0006] The present invention has been made to solve these problems, and an object of the present invention is to provide a booster pump capable of improving the accuracy of the gap dimension between an impeller and a casing accommodating the impeller, relaxing the accuracy of casing components, and facilitating assembly work.

[0007] In order to achieve the above object, the present invention includes the following structures. A booster pump comprises: an impeller having a plurality of blades formed along the outer peripheral edge of a disc-shaped main plate; a pump housing, a first housing and a second housing directly overlapping each other at the radially outer side, the impeller being rotatably accommodated between the first housing and the second housing, the pump housing respectively forming a boost flow path along the outer peripheral edge of the impeller and a suction flow path and a discharge flow path connected to the boost flow path via a partition wall; and an electric motor comprising: a rotating shaft connected to an end of a shaft to which the impeller is connected, a rotor connected to the rotating shaft and a stator arranged opposite to the rotor, characterized in that a force applying member is sandwiched between the axial inner end surface of the pump housing and the first housing, the force applying member causing the first housing to always apply force to the second housing.

[0008] As described above, since the first housing and the second housing are directly overlapped at the radially outer side and the impeller is rotatably accommodated between the first housing and the second housing, there is no need for an annular element between the first housing and the second housing as in the prior art document, and the number of components is reduced, thereby improving the accuracy of the gap size between the impeller and the first housing and the second housing. In addition, since a force applying member is sandwiched between the axially inner end surface of the pump housing and the first housing so that the first housing always applies force to the second housing, it is not necessary to form the axially inner end surface of the pump housing within the axial height range formed by the direct overlap of the first housing and the second housing at the radially outer side, thereby easing the accuracy of the components of the pump housing and making it easy to perform assembly operations.

[0009] Preferably, the urging member has a bottomed cylindrical portion at a central portion that fits into a recess of the first housing and accommodates an end portion of the rotating shaft, and a disc portion extending radially outward from the bottom of the bottomed cylindrical portion is sandwiched by the pump housing and the first housing. Thus, the bottomed cylindrical portion is fitted into the recessed portion of the first housing, and positional displacement of the urging member can be prevented. Effects of the Invention

[0010] A booster pump can be provided in which the accuracy of the gap dimension between an impeller and a casing accommodating the impeller can be adjusted without depending on the accuracy of the components themselves and the assembling operation is easy. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a cross-sectional view of a booster pump. Figure 2 It is a partially enlarged cross-sectional view of FIG1 . Figure 3 It is a horizontal cross-sectional explanatory view showing the structure of the cascade pump of FIG. 1 . FIG. 4 is a top view, a right side view, and a perspective view of the urging member of FIG. 1 . DETAILED DESCRIPTION

[0012] Hereinafter, an embodiment of the booster pump of the present invention will be described with reference to the accompanying drawings. First, the structure of the booster pump 1 will be described with reference to Fig. 1. Hereinafter, as an example of the booster pump 1, a water supply pump connected to a tap water pipe of a concentrated residence such as a residential building or an apartment is illustrated. like Figure 1B As shown, the booster pump 1 is provided with a water supply port 3a for connection of a tap water pipe and a drain port 3b for draining the pressurized tap water on the side surface of the exterior cover 2.

[0013] The booster pump 1 contains the following structure in a housing formed by a bottom plate 4 covered by 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 thereof. The tap water pressurized by the cascade pump 5 is temporarily stored in a storage tank 7. This can mitigate instantaneous changes in water pressure such as pulsation and impact of the tap water.

[0014] A natural cooling fan 8 is provided on the upper part of the motor 6 to cool the heat generated by the motor coil of the stator. An inlet 10 for sending air to the natural cooling fan 8 is provided on the upper part of the natural cooling fan 8. The electronic substrate 9 includes a control unit (MPU) for controlling the operation of the device, a ROM for storing an operation program, and a storage unit such as a RAM for temporarily storing input and output data or reading an operation program and used as a work area of ​​the CPU. In addition, a display 11 is provided on the upper part of the exterior cover 2. The display 11 is provided with a display unit for displaying input keys, input data, operation status, etc.

[0015] The cascade pump 5 includes an impeller 5a, which is formed with a plurality of blades erected along the outer peripheral edge of a disk-shaped main plate and has blade grooves separated by the plurality of blades. The impeller 5a is assembled near the shaft end (lower end) of the rotating shaft 6a of the motor 6 by the impeller fixing member 5b in the axial direction and is prevented from coming off by the impeller fixing member 5b. The motor 6 driving the cascade pump 5 includes: the rotating shaft 6a to which the impeller 5a is connected at the shaft end; the rotor 6b connected to the rotating shaft 6a; and the stator 6c arranged relatively to surround the rotor 6b.

[0016] like Figure 2 As shown, a pump housing 12 is installed on the bottom plate 4. In the pump housing 12, the first housing 12a and the second housing 12b are assembled in a manner of directly overlapping each other on the radially outer side. An annular element as in the prior art is not required between the first housing 12a and the second housing 12b, and the number of parts is reduced. Therefore, the accuracy of the gap size between the impeller 5a and the first housing 12a and the second housing 12b can be improved. In addition, a very small gap (for example, less than 0.05 mm) is provided between the impeller 5a and the first housing 12a and the second housing 12b, and the impeller 5a is accommodated in a rotatable manner.

[0017] like Figure 3 As shown, the cascade pump 5 is formed with a booster flow path 12c, a suction flow path 12e and a discharge flow path 12f in the pump housing 12, the booster flow path is along the outer peripheral edge of the impeller 5a, and the suction flow path and the discharge flow path are connected to the booster flow path 12c via a partition 12d. The suction flow path 12e is connected to the water supply port 3a, and the discharge flow path 12f is connected to the storage tank 7 (refer to Figure 1A ) connected.

[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. Figure 4A , Figure 4B , Figure 4C As shown, the force-applying member 13 has a bottomed cylindrical portion 13a in the center portion for accommodating the axial end portion of the rotating shaft 6a, and a circular plate portion 13b connected radially outward from the bottom of the bottomed cylindrical portion 13a is clamped by the pump housing 12 (lower end surface 12g) and the first housing 12a. The force-applying member 13 uses an elastic member such as fluororubber. The inner side of the bottomed cylindrical portion 13a is hollow, and by accommodating the axial end portion of the rotating shaft 6a and the impeller fixing member 5b assembled to the axial end portion in this portion, the rotating shaft 6a and the force-applying member 13 will not interfere with each other and will not affect the rotational movement of the impeller 5a. In addition, by fitting the bottomed cylindrical portion 13a with the recessed portion 12h of the first housing 12a, it is possible to prevent the position of the force-applying member 13 from being offset (see Figure 2 ). In this way, since the force-applying member 13 causes the first housing 12a to always apply force to the second housing 12b, there is no need to form the axial inner end face 12g of the pump housing 12 within the axial height range formed by the direct overlap of the first housing 12a and the second housing 12b on the radial outside. Therefore, the component accuracy of the pump housing 12 can be relaxed and the assembly operation can be easily performed.

[0019] The rotating 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 coaxially fitted with the rotating shaft 6a is fixed to the second housing 12b. The mechanical seal 14 can prevent the tap water from leaking from the pressure-increasing flow path 12 c to the rotating shaft 6 a side.

[0020] The above-mentioned booster pump 1 is not limited to water supply equipment in centralized residences such as residential buildings, but can also be applied to water supply facilities in offices, schools, etc., and can provide a booster pump that can improve the accuracy of the gap size between the impeller and the pump casing that accommodates the impeller, or can relax the accuracy of the components of the pump casing, and the assembly operation is also easy.

Claims

1. A booster pump, comprising: An impeller having a plurality of blades formed along the outer peripheral edge of a disk-shaped main plate; a pump casing, wherein a first casing and a second casing are directly overlapped at radially outer sides, the impeller is rotatably accommodated between the first casing and the second casing, and the pump casing is respectively formed with a boosting flow path along the outer peripheral edge of the impeller and a suction flow path and a discharge flow path connected to the boosting flow path via a partition wall; and The electric motor includes a rotating shaft whose impeller is connected to an end of the shaft, a rotor connected to the rotating shaft, and a stator arranged opposite to the rotor. The invention is characterized in that a biasing member is interposed between the axial inner end surface of the pump housing and the first housing, and the biasing member causes the first housing to always bias the first housing toward the second housing.

2. The booster pump according to claim 1, characterized in that: The urging member has a bottomed cylindrical portion at the center thereof that fits into the recess of the first housing and accommodates the axial end of the rotating shaft. A disc portion extending radially outward from the bottom of the bottomed cylindrical portion is clamped by the pump housing and the first housing to urge the second housing.

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