Pump System

Abstract

A pump system includes: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, in which the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface, and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, and the motor housing includes a second fitting portion having a columnar outer circumferential surface and a second flange portion, and on an outer circumferential surface of the second fitting portion, protrusions are formed.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims priority under 35 U.S.C. .sctn. 119 to Japanese Patent Application 2016-185301, filed on Sep. 23, 2016, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

[0002] This disclosure relates to a pump system in which a flow path housing, through which a fluid flows, and a motor housing, which drives a pump rotor inside the flow path housing, are connected to each other.

BACKGROUND DISCUSSION

[0003] As an example of a pump system that supplies cooling water to an engine of a vehicle, JP 2008-025538 A (Reference 1) discloses a technique in which a flow path housing (referred to as a pump case in Reference 1) is attached to a motor housing (referred to as a motor case in Reference 1) that constitutes a motor unit, and a pump rotor having a plurality of impellers is accommodated in the flow path housing.

[0004] In Reference 1, a shaft is provided of which one end is supported by the motor housing and the other end supported by the flow path housing, and a rotor unit is rotatably fitted on the shaft. The pump rotor is configured by providing a permanent magnet to the rotor unit and providing a plurality of impellers at the end position of the rotor unit.

[0005] In addition, in Reference 1, in view of the drawings thereof, the motor housing and the flow path housing are connected to each other by making flange portions formed on the motor housing and the flow path housing abut on each other and fitting the fitting portions formed on the outer circumferences of the flange portions to each other.

[0006] In the water pump described in Reference 1, the flow path housing is formed of a resin, and the portion of the motor housing, which is fitted to the flow path housing, is formed of a resin. Even in the configuration provided with such fitting structures, it is difficult to maintain high fitting accuracy since the fitting structures are both formed of a resin material.

[0007] Therefore, in the configuration in which one end of the shaft is supported by the motor housing and the other end is supported by the flow path housing, it is also considered that axial centering accuracy may be deteriorated.

[0008] In order to solve the problems, a configuration in which the flow path housing and the motor housing are formed of a metal material and are fitted to each other in the same manner as in Reference 1 is effective. However, when considering insulation performance or manufacturing costs, it is required to use a resin material for the motor housing.

[0009] Thus, a need exists for a pump system which is not susceptible to the drawback mentioned above.

SUMMARY

[0010] A feature of a pump system according to an aspect of this disclosure resides in that the pump system includes: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, in which the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, the motor housing includes a second fitting portion having a columnar outer circumferential surface fitted into the first fitting portion and a second flange portion connected to the first flange portion, and on an outer circumferential surface of the second fitting portion, a plurality of protrusions are formed to protrude to a position at which the protrusions have a diameter larger than an inner diameter of the inner circumferential surface of the first fitting portion, and the first fitting portion and the second fitting portion are connected to each other in a state where a gasket is sandwiched between the first flange portion and the second flange portion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein:

[0012] FIG. 1 is a partially cut-away side view of a pump system;

[0013] FIG. 2 is an exploded side view of the pump system, a portion of which is illustrated in a cross section;

[0014] FIG. 3 is a view illustrating the arrangement of a second flange portion, a second fitting portion, protruding pieces, and so on;

[0015] FIG. 4 is a view illustrating the arrangement of a first flange portion, a first fitting portion, and so on;

[0016] FIG. 5 is a perspective view illustrating the shapes of a protruding piece and a recessed portion; and

[0017] FIG. 6 is a cross-sectional view illustrating the state of a protrusion in a state where the first fitting portion and the second fitting portion are fitted to each other.

DETAILED DESCRIPTION

[0018] Hereinafter, embodiments disclosed here will be described based on the drawings.

[Basic Configuration]

[0019] As illustrated in FIG. 1, a pump system 100 is configured by fitting and connecting a metallic flow path housing 10, which is connected to the bottom wall of an engine 1 so as to return, to the engine 1, cooling water (an example of the fluid) returned from a radiator and so on via a hose 2, and a resin motor housing 20 configured to drive a pump unit P inside the flow path housing 10 and accommodate an electric motor M therein.

[0020] In the pump system 100, when the engine 1 is operated, a pump rotor 22 of the pump unit P is driven by driving force of the electric motor M accommodated in the motor housing 20, so that circulation of the cooling water is implemented in the form of suctioning the cooling water from the radiator and so on into the flow path housing 10 and returning the cooling water to a water jacket of the engine 1.

[Flow Path Housing]

[0021] As illustrated in FIGS. 1 and 2, the flow path housing 10 includes a flow path housing body 11 in which a flow path space is formed to deliver the cooling water. The flow path housing body 11 is integrally formed, on the base end side thereof, with a discharge portion 12, which is connected to the bottom portion of the engine 1, and is provided, on the outer end side thereof, with a suction portion 13, to which the hose 2 is connected.

[0022] In the pump system 100, since the pump unit P is formed in a centrifugal type, a circular pump chamber 11a centered on the center axis X is formed in the flow path housing body 11, and a discharge flow path 11b is formed to extend from the outer circumference of the pump chamber 11a toward the discharge portion 12.

[0023] A connecting portion 14 is formed in a flange shape on the discharging portion 12 to connect the flow path housing body 11 to the engine 1. When the connecting portion 14 is connected to the engine 1 by connecting bolts 3, the discharge flow path 11b of the discharge portion 12 communicates with the water jacket of the engine 1.

[0024] In addition, the suction portion 13 is formed in a cylindrical shape and fixed to the flow path housing body 11 by fixing bolts 4 in a direction along the center axis X. As a result, the suction portion 13 and the pump chamber 11a communicate with each other. In addition, a support portion 15 is formed coaxially with the center axis X inside the flow path housing body 11 to support the axial end of a rotor shaft 21 of the pump rotor 22. In addition, the suction portion 13 may be integrally formed with the flow path housing 10.

[0025] In the pump system 100, the rotor shaft 21 is fixedly installed in the motor housing 20, and a motor rotor (not illustrated) and the pump rotor 22, which is integrally formed with the motor rotor, are rotatably supported with respect to the rotor shaft 21. In addition, instead of this configuration, the pump system 100 may be configured such that the rotor shaft 21 is provided to be driven by the electric motor M and the pump rotor 22 rotates integrally with the rotor shaft 21.

[0026] In particular, as illustrated in FIG. 4, the flow path housing body 11 includes a first fitting portion 16, which has a cylindrical inner circumferential surface having a circular cross-sectional shape centered on the center axis X, and a first flange portion 17, which has a first connecting surface 17S in the attitude perpendicular to the center axis X of the inner circumferential surface. A plurality of (four in this embodiment) screw-hole portions 17a are formed in the first flange portion 17.

[0027] The four screw-hole portions 17a are formed at positions at which the circumference centered on the center axis X is equally divided into four portions (positions at which 360 degrees are divided by 90 degrees around the center axis X).

[0028] In addition, a seal groove 17G, which has a circular shape centered on the center axis X, is formed in the first connecting surface 17S of the first flange portion 17, and an annular gasket 6 formed of a flexible material such as rubber or resin, is fitted therein. The gasket 6 used here is sized to slightly protrude from the first connecting surface 17S.

[Motor Housing]

[0029] As illustrated in FIGS. 1 to 3, the motor housing 20 accommodates the electric motor M therein, and includes the rotor shaft 21 coaxially disposed with the center axis X. The pump rotor 22 is supported by the rotor shaft 21, and a plurality of impellers 22a are formed on the pump rotor 22.

[0030] The motor housing 20 is provided with a second fitting portion 23, which has a columnar shape centered on the center axis X and has a columnar outer circumferential surface centered on the center axis X so as to be fittable into the first fitting portion 16, and a second flange portion 24, which has a second connecting surface 24S in the attitude perpendicular to the center axis X. A plurality of bolt insertion holes 24a (four in this embodiment) are formed in the second flange portion 24.

[0031] In addition, the four bolt insertion holes 24a are formed at positions at which the circumference around the rotor shaft 21 is equally divided into four portions so as to correspond to the four screw-hole portions 17a.

[0032] As illustrated in FIG. 3, a plurality of (four) protruding pieces 25 (e.g., protrusions) each having a thin plate shape are formed on the outer circumferential surface of the second fitting portion 23 on imaginary straight lines that interconnect the center axis X and the respective bolt insertion holes 24a. The protruding pieces 25 are formed to protrude to a position at which the protruding pieces 25 have a diameter larger than the inner diameter of the inner circumferential surface of the first fitting portion 16. That is, the protruding distance D to the protruding end of each protruding piece 25 based on the center axis X is set to a value that is larger than the radius R of the inner circumferential surface of the first fitting portion 16, as illustrated in FIG. 4.

[0033] As illustrated in FIG. 2, compared with the fitting distance L (fitting margin) of the second fitting portion 23 in the direction along the center axis X, the region length N of the protruding piece 25 from the second connecting surface 24S is set to a value that is smaller than the fitting distance L. In addition, as illustrated in FIG. 4, the protruding distance D to the protruding end of the protruding piece 25 based on the center axis X is set to a value that is sufficiently smaller than the groove radius E to the inner position of the seal groove 17G, which has a circular shape centered on the center axis X, in the first connecting surface 17S. In particular, the offset distance Q from the first fitting portion 16 to the inner position of the seal groove 17G is longer than the region length N.

[0034] In addition, as illustrated in FIGS. 3 and 5, in the second connecting surface 24S of the second flange portion 24, a recessed portion 26 is formed in a region surrounding the protruding piece 25 when viewed in the direction along the center axis X. In particular, since the protruding piece 25 is integrally formed with the motor housing 20, the protruding piece 25 is also formed of a resin material.

[0035] As illustrated in FIG. 1, in the state where the second fitting portion 23 is fitted to the first fitting portion 16 and connected by fastening bolts 5, the pump unit P is constituted by the pump rotor 22 and the pump chamber 11a in which the pump rotor 22 is disposed. Details of this fitting connection will be described later.

[0036] The motor housing 20 includes a connector portion 27 provided on the outer end of the second flange portion 24. In addition, a cover body 28 is provided to cover the motor housing 20, and a flange-shaped connecting body 28a is integrally formed on the cover body 28 to overlap the outer surface side of the second flange portion 24. The connecting body 28a has hole portions 28b formed at positions at which the hole portions 28b overlap the bolt insertion holes 24a in the second flange portion 24.

[Fitting Connection]

[0037] When the first fitting portion 16 and the second fitting portion 23 are fitted and connected to each other, the operations of setting the pump rotor 22 in the motor housing 20, disposing the cover body 28 at the position at which it covers the motor housing 20, and inserting the outer circumferential surface of the second fitting portion 23 into the inner circumferential surface of the first fitting portion 16 are performed.

[0038] During the operations, a fastening operation is performed by inserting the fastening bolt 5 from the hole portion 28b of the connecting body 28a through the bolt insertion hole 24a in the second flange portion 24, and screwing the fastening bolt 5 into the screw-hole portion 17a of the first flange portion 17.

[0039] When the fastening operation is performed, the motor housing 20 is displaced relative to the first fitting portion 16 in the direction in which the second fitting portion 23 is inserted in the direction along the center axis X. With this displacement, a portion of the plurality (four) of the protruding pieces 25, which protrudes outward from the opening of the first fitting portion 16, comes into contact with the opening edge of the first fitting portion 16, thereby being scraped and, at the same time, pressed (crushed). Thereby, as illustrated in FIG. 6, the gap between the inner circumferential surface of the first fitting portion 16 and the outer circumferential surface of the second fitting portion 23 is filled with the protruding pieces 25.

[0040] In this fastening operation, by equally operating the four fastening bolts 5, for example, the trouble of causing the rotor shaft 21 to be tilted with respect to the center axis X or the trouble of causing the rotor shaft 21 to have a positional relationship in which the rotor shaft 21 deviates from the center axis X may be eliminated even in a state where a gap is present between the inner circumferential surface of the first fitting portion 16 and the outer circumferential surface of the second fitting portion 23. Thus, the axial end of the rotor shaft 21 on the protruding side is accurately fitted into the supporting portion 15 of the flow path housing 10.

[0041] In addition, when the shape of the protruding pieces 25 is changed as described above, the protruding pieces 25 may be partially scraped by the opening edge of the first fitting portion 16 to form fine resin pieces, and the fine resin pieces may be accommodated in the recessed portions 26. As a result, it is possible to eliminate the trouble of causing the fine resin pieces to be sandwiched between the first connecting surface 17S and the second connecting surface 24S.

[0042] As described above, since the offset distance Q is longer than the region length N, for example, even if the resin of the protruding pieces 25, which are scraped by the opening edge of the first fitting portion 16, falls in a long piece state in the direction of the gasket 6 without being cut, the resin in the long piece state does not come into contact with the gasket 6 and the sealing property is not impaired since the maximum length of the resin in the long piece state is the region length N.

[0043] By continuing the fastening operation, the second connecting surface 24S is brought into the state in which the second connecting surface 24S abuts on the first connecting surface 17S, and the gasket 6 is sandwiched therebetween, thereby implementing the sealed state. In addition, the connecting body 28a of the cover body 28 is pressed against the outer surface side of the second flange portion 24 by the fastening operation, so that the cover body 28 covers the motor housing 20.

[0044] As described above, in the state where the second fitting portion 23 is fitted to the first fitting portion 16, even if a gap is present between the inner circumferential surface of the first fitting portion 16 and the outer circumferential surface of the second fitting portion 23, the deformed protruding pieces 25 reliably come into contact with the inner circumferential surface of the first fitting portion 16 so as to maintain the flow path housing 10 and the motor housing 20 in a predetermined proper positional relationship.

OTHER EMBODIMENTS

[0045] This disclosure may adopt other configurations as follows, in addition to the above embodiment (the same reference numerals as those in the embodiment are given to components having functions similar to those in the embodiment).

[0046] (a) The number of the protruding pieces 25 (e.g. protrusions) is set to 3 or 4 or more. Although it is ideal that, with the configuration in which the above-mentioned number is set, all of the protruding pieces 25 are disposed at the positions corresponding to the fastening portions of the fastening bolts 5 that connect the first flange portion 17 and the second flange portion 24 to each other, some of the protruding pieces 25 may be disposed at positions spaced apart from the fastening positions.

[0047] (b) The plate thickness of the protruding pieces 25 (e.g. protrusions) may be set to be thicker toward the second connecting surface 24S or the protrusion amount of the protruding pieces 25 based on the outer circumferential surface of the second fitting portion 23 may be set to be larger toward the second connecting surface 24S. When the protruding pieces 25 are formed in this way, it is possible to create a better fitting state.

[0048] This disclosure may be used in a pump system in which a motor housing is connected to a flow path housing.

[0049] A feature of a pump system according to an aspect of this disclosure resides in that the pump system includes: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, in which the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, the motor housing includes a second fitting portion having a columnar outer circumferential surface fitted into the first fitting portion and a second flange portion connected to the first flange portion, and on an outer circumferential surface of the second fitting portion, a plurality of protrusions are formed to protrude to a position at which the protrusions have a diameter larger than an inner diameter of the inner circumferential surface of the first fitting portion, and the first fitting portion and the second fitting portion are connected to each other in a state where a gasket is sandwiched between the first flange portion and the second flange portion.

[0050] With this configuration, in a case where an operation of fitting the second fitting portion of the motor housing into the first fitting portion of the flow path housing is performed, since the first fitting portion is formed of a metal and the second fitting portion is formed of a resin, in the plurality of protrusions protruding from the outer circumferential surface of the second fitting portion, a portion thereof that has a diameter larger than that of the inner circumferential surface of the first fitting portion is scraped or crushed, so that the protrusions are brought into close contact with the inner circumferential surface of the first fitting portion. That is, even if a gap is present between the inner circumferential surface of the first fitting portion and the outer circumferential surface of the second fitting portion, the gap may be filled with some of the plurality of protrusions. As a result, even if the first flange portion and the second flange portion are connected to each other in a state where the gasket is sandwiched therebetween, the connection is implemented in a state where rattling is suppressed between the first fitting portion and the second fitting portion.

[0051] Therefore, the pump system is configured in which the motor housing and the flow path housing are fitted and connected to each other with high accuracy while the motor housing is formed of a resin material.

[0052] In the aspect of this disclosure, the plurality of protrusions may be pressed on an inner surface of the first fitting portion in a state where the first fitting portion and the second fitting portion are fitted to each other.

[0053] With this configuration, in a state where the first fitting portion and the second fitting portion are fitted to each other, the plurality of protrusions are present in a pressed state between the inner circumferential surface of the first fitting portion and the outer circumferential surface of the second fitting portion. Thus, since the gap is filled with the pressed protrusions, a good connection state is implemented without rattling.

[0054] In the aspect of this disclosure, the second flange portion may have a recessed portion formed in a concave shape in a region of a connecting surface thereof that surrounds the protrusion when viewed in a direction along the center axis.

[0055] With this configuration, when performing an operation of fitting the second fitting portion of the motor housing into the first fitting portion of the flow path housing, even if a portion of the protrusion is scraped by the first fitting portion to form fine resin pieces, the resin pieces are accommodated in the recessed portion, thereby suppressing the trouble of causing the resin pieces to be interposed between the abutment surfaces of the first flange portion and the second flange portion.

[0056] In the aspect of this disclosure, the protrusions may be disposed near a plurality of fastening portions in which the first flange portion and the second flange portion are fastened to each other by a bolt.

[0057] With this configuration, when the first flange portion and the second flange portion are fastened to each other by a plurality of bolts, strong force is applied to the protrusions by fastening force of the bolts, thereby enabling transition to the connection state.

[0058] The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.

Claims

1. A pump system comprising: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, wherein the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface, and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, the motor housing includes a second fitting portion having a columnar outer circumferential surface fitted into the first fitting portion and a second flange portion connected to the first flange portion, and on an outer circumferential surface of the second fitting portion, a plurality of protrusions are formed to protrude to a position at which the protrusions have a diameter larger than an inner diameter of the inner circumferential surface of the first fitting portion, and the first fitting portion and the second fitting portion are connected to each other in a state where a gasket is sandwiched between the first flange portion and the second flange portion.

2. The pump system according to claim 1, wherein the plurality of protrusions are pressed on an inner surface of the first fitting portion in a state where the first fitting portion and the second fitting portion are fitted to each other.

3. The pump system according to claim 1, wherein the second flange portion has a recessed portion formed in a concave shape in a region of a connecting surface thereof that surrounds the protrusion when viewed in a direction along the center axis.

4. The pump system according to claim 1, wherein the protrusions are disposed near a plurality of fastening portions in which the first flange portion and the second flange portion are fastened to each other by a bolt.

5. A pump system comprising: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, wherein the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface, and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, the motor housing includes a second fitting portion having a columnar outer circumferential surface fitted into the first fitting portion and a second flange portion connected to the first flange portion, and on an outer circumferential surface of the second fitting portion, a plurality of protrusions are formed to protrude to a position at which the protrusions have a diameter larger than an inner diameter of the inner circumferential surface of the first fitting portion, the first fitting portion and the second fitting portion are connected to each other in a state where a gasket is sandwiched between the first flange portion and the second flange portion, the plurality of protrusions are pressed on an inner surface of the first fitting portion in a state where the first fitting portion and the second fitting portion are fitted to each other, and the second flange portion has a recessed portion formed in a concave shape in a region of a connecting surface thereof that surrounds the protrusion when viewed in a direction along the center axis.

6. A pump system comprising: a metallic flow path housing including a suction portion configured to suction a fluid and a discharge portion configured to deliver the suctioned fluid; and a resin motor housing configured to drive a pump rotor existing inside the flow path housing in a state of being fitted and connected to the flow path housing, wherein the flow path housing includes a first fitting portion having a cylindrical inner circumferential surface, and a first flange portion in an attitude perpendicular to a center axis that becomes a center of the inner circumferential surface, the motor housing includes a second fitting portion having a columnar outer circumferential surface fitted into the first fitting portion and a second flange portion connected to the first flange portion, and on an outer circumferential surface of the second fitting portion, a plurality of protrusions are formed to protrude to a position at which the protrusions have a diameter larger than an inner diameter of the inner circumferential surface of the first fitting portion, the first fitting portion and the second fitting portion are connected to each other in a state where a gasket is sandwiched between the first flange portion and the second flange portion, the plurality of protrusions are pressed on an inner surface of the first fitting portion in a state where the first fitting portion and the second fitting portion are fitted to each other, the second flange portion has a recessed portion formed in a concave shape in a region of a connecting surface thereof that surrounds the protrusion when viewed in a direction along the center axis, and the protrusions are disposed near a plurality of fastening portions in which the first flange portion and the second flange portion are fastened to each other by a bolt.