Pump device

Abstract

A pump device (1) comprises: a rotor (6) provided with an impeller (62) and a magnet (63); a housing (4) accommodating the rotor (6); a stator (7) that faces the rotor (6) in the radial direction and that is fixed to the housing (4); a case (5) accommodating the housing (4); and an elastic member (91) sandwiched between the housing (4) and the case (5). The housing (4) is supported by the elastic member (91) so as to be displaceable with respect to the case (5) in the axial direction and the radial direction.

Description

Pump device

[0001] The present invention relates to a pump device.

[0002] For example, Patent Document 1 discloses a water pump provided with a cover that covers a circuit board. In this water pump, in order to suppress resonance during the driving of the motor unit, a throttle portion is formed on the bottom wall of the cover that covers the circuit board for driving and controlling the motor unit.

[0003] Japanese Patent Application Laid-Open No. 2015-119597

[0004] In, for example, an electric vehicle (EV) in which a water pump is incorporated, since an engine is not mounted, ensuring quietness is particularly required. In ensuring quietness, in a pump device including a water pump or the like, it is necessary to suppress vibration as much as possible.

[0005] The present invention has been made in view of the above problems, and one of the problems is to provide a pump device capable of suppressing vibration.

[0006] A pump device according to an aspect of the present invention includes a rotor including an impeller and a magnet, a housing that houses the rotor, a stator that is fixed to the housing so as to face the rotor in the radial direction, a case in which the housing is housed, and an elastic member sandwiched between the housing and the case. The elastic member supports the housing so as to be displaceable with respect to the case in the axial direction and the radial direction.

[0007] It is a perspective view schematically showing the structure of a pump device 1 according to an embodiment of the present invention. It is a cross-sectional view taken along line 2-2 of FIG. 1. It is an exploded perspective view schematically showing the structure of a pump device 1 according to an embodiment of the present invention. It is a cross-sectional view taken along line 4-4 of FIG. 2. It is a partially enlarged cross-sectional view taken along line 5-5 of FIG. 1. FIG. 6 is a partially enlarged cross-sectional view in which a part of FIG. 5 is further enlarged.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the attached drawings. Figure 1 is a schematic perspective view showing the structure of a pump device 1 according to an embodiment of the present invention. This pump device 1 is, for example, a water pump. A water pump is a centrifugal pump for transferring (pressurizing) a fluid, i.e., a coolant (liquid). The pump device 1 is installed, for example, in the engine room of a gasoline-powered vehicle or the motor room of an electric vehicle (EV). The pump device 1 is used to cool a drive source such as the engine or motor of such a vehicle by transferring coolant to the drive source.

[0009] In pump device 1, the direction along axis x is defined as the axial direction. In this axial direction, one side is defined as the upper side and the other side as the lower side. The upper and lower sides do not necessarily coincide with the upper and lower sides in the direction of gravity. Furthermore, the direction perpendicular to axis x is defined as the radial direction. In the radial direction, the direction approaching axis x is defined as the inner circumference side and the direction moving away from axis x is defined as the outer circumference side. In addition, a circumferential direction is defined around axis x. The clockwise and counterclockwise directions in the circumferential direction are defined as the direction when viewed from the upper side in the axial direction.

[0010] Figure 1 is a perspective view of the pump device 1, viewed from above in the axial direction. The pump device 1 includes a casing 2 that is generally cylindrical in shape with respect to the axis x. The casing 2 has a cover 3, a housing 4, and a case 5. In this example, the cover 3 covers the upper side of the housing 4, while the case 5 covers the lower side of the housing 4. The housing 4 is housed in the case 5. The cover 3, housing 4, and case 5 are each formed (e.g., by injection molding) from a thermoplastic resin material, such as PPS (polyphenylene sulfide). However, the case 5 may be formed from a metal material, such as aluminum, instead of a resin material.

[0011] The cover 3 has a main body 31 formed in an annular shape around an axis x, and an inlet 32 ​​and an outlet 33 integrally formed on the main body 31. The main body 31 is formed, for example, in a generally frustoconical shape with the axis x as the center. The inlet 32 ​​protrudes upward from the upper surface of the main body 31 along the axis x. The inlet 32 ​​is formed, for example, in a cylindrical shape with the axis x as the center. An inlet 34 is formed at the upper end of the inlet 32. The inlet 32 ​​allows fluid to flow into the internal space of the casing 2 from the inlet 34. Note that the inlet 34 may be formed directly on the upper surface of the main body 31 by omitting the formation of the cylindrical inlet 32.

[0012] The outlet section 33 protrudes from the side surface of the main body 31 toward the outer circumference along the tangent to a virtual circle centered on axis x. The outlet section 33 is formed, for example, in a cylindrical shape centered on the tangent. An outlet 35 is formed at the tip of the outlet section 33. The outlet section 33 causes fluid to flow out of the internal space of the casing 2 through the outlet 35. In this way, in the pump device 1, the coolant that flows into the internal space of the casing 2 along the axial direction flows out of the internal space of the casing 2 along the tangent direction of a virtual circle centered on axis x. Note that the outlet 35 may be formed directly on the side surface of the main body 31 by omitting the formation of the cylindrical outlet section 33.

[0013] Figure 2 is a cross-sectional view along line 2-2 in Figure 1. Figure 3 is an exploded perspective view schematically showing the structure of a pump device 1 according to one embodiment of the present invention. Referring together to Figures 2 and 3, the housing 4 has a bottom plate 41, an inner wall 42, a top plate 43, an outer wall 44, and a flange 45. The bottom plate 41 is formed, for example, in the shape of a flat disc perpendicular to the axis x. The inner wall 42 extends upward from the upper surface of the bottom plate 41. The inner wall 42 is formed in the shape of a cylinder centered on the axis x. The top plate 43 extends outward from the upper edge of the inner wall 42. The top plate 43 is formed in the shape of a disc centered on the axis x. The outer wall 44 extends downward from the outer edge of the top plate 43. The outer wall 44 is formed in the shape of a cylinder centered on the axis x.

[0014] In this example, the outer wall 44 extends axially below the inner wall 42. The outer peripheral end of the bottom plate 41 is connected to the inner peripheral surface of the outer wall 44. In this example, the flange 45 extends annularly outward from near the upper end of the outer wall 44. The main body 31 of the cover 3 is supported on the top plate 43, the outer wall 44, and the flange 45. Specifically, a projection 36 extending cylindrically downward from the outer peripheral edge of the main body 31 of the cover 3 fits into an annular groove 46 formed on the upper surface of the flange 45. In this way, the cover 3 covers the housing 4 from above. The projection 36 of the cover 3 is joined to the housing 4 by ultrasonic welding in an annular region around the axis x, for example.

[0015] Case 5 includes a bottom plate 51, a side wall 52, one or more bracket portions 53, and a flange 54. The bottom plate 51 is formed from a flat plate that extends along a plane perpendicular to the axis x. The side wall 52 extends upward from the outer edge of the bottom plate 51. The side wall 52 is formed in a cylindrical shape centered on the axis x. In this example, the side wall 52 covers the outer wall 44 of the housing 4 from the outer periphery. For example, three bracket portions 53 protrude outward from the outer surface of the side wall 52. The three bracket portions 53 are arranged at predetermined intervals (for example, at equal intervals) around the axis x. The bracket portions 53 are parts that hold bolts, cushioning members such as rubber (neither of which are shown), etc., for attaching the pump device 1 to the mounting target.

[0016] In this example, the flange 54 extends from the upper end of the side wall 52 outward. The flange 54 supports the flange 45 of the housing 4 on its upper surface. Thus, the flange 45 of the housing 4 is sandwiched between the outer peripheral end of the main body 31 of the cover 3 and the flange 54 of the case 5. The main body 31 and the flange 54 are connected to each other by one or more fixing members (not shown), such as screws. As shown in Figure 3, a recess (hereinafter referred to as a notch 55) with a hole that penetrates the side wall 52 radially is formed in a part of the circumferential direction of the side wall 52. In one example, the notch 55 is formed from the upper end to the lower end of the side wall 52. A part of the outer peripheral surface of the outer wall 44 of the housing 4 is exposed within this notch 55.

[0017] An internal space S is formed within the casing 2 by the cover 3 and the housing 4. The internal space S has a first space S1 formed by the main body 31 of the cover 3 and the top plate 43 of the housing 4, and a second space S2 formed by the bottom plate 41 of the housing 4 and the inner wall 42. The inlet 32 ​​and outlet 33 are connected to the first space S1. The coolant that flows into the first space S1 from the inlet 34 is discharged to the outside of the pump device 1 via the outlet 35. The coolant may include, for example, water. Other liquids may be included in the water. Other liquids may include, for example, antifreeze such as propylene glycol or ethylene glycol, or rust inhibitors.

[0018] In this example, the first space S1 is generally frustoconical in shape, although it includes, for example, a cylindrical space centered on axis x. The second space S2 is also generally cylindrical in shape, centered on axis x. In the radial direction, the maximum diameter (dimension) of the first space S1 in the cylindrical space is greater than the maximum diameter (dimension) of the second space S2. On the other hand, in the axial direction, the maximum height of the first space S1 is less than the height of the second space S2. These first space S1 and second space S2 are connected to each other. Therefore, the coolant flowing into the first space S1 also flows into the second space S2.

[0019] An axially extending shaft 47 is arranged in the internal space S. The shaft 47 is formed in a cylindrical shape, for example, with axis x as its center. The upper end of the shaft 47 is fixed to the holding portion 37 of the cover 3, while the lower end of the shaft 47 is fixed to the bottom plate 41. Specifically, the upper end of the shaft 47 is held and fixed in a recess 37a formed on the lower surface of the holding portion 37. The lower end of the shaft 47 is held and fixed in a bottomed hole 41a formed in the bottom plate 41. For fixing, the lower end of the shaft 47 is, for example, press-fitted into the bottomed hole 41a. Alternatively, a through hole may be formed in the bottom plate 41 instead of the bottomed hole 41a.

[0020] The lower surface of the holding portion 37 extends along a plane perpendicular to the axis x, for example. The holding portion 37 is positioned to enter the first space S1 from the lower end of the inlet portion 32 along the axis x. The holding portion 37 is connected to the main body 31 by a plurality of spokes 38. The plurality of spokes 38 connect the holding portion 37 and the main body 31 to each other. In this example, three spokes 38 are arranged in the circumferential direction at predetermined intervals (for example, equal intervals). The holding portion 37 and the spokes 38 are integrally formed with the main body 31.

[0021] The pump device 1 includes a rotor 6 rotatably supported on a shaft 47 about an axis x. The rotor 6 is housed in the internal space S of the casing 2, i.e., the housing 4. The rotor 6 includes a bearing 61, an impeller 62, and a magnet 63. The bearing 61 is formed in a cylindrical shape along the axis x. The inner circumferential surface of the bearing 61 faces the outer circumferential surface of the shaft 47 with a predetermined gap between them. Thus, the bearing 61 is configured to be rotatable about the axis x and movable in the vertical direction along the axis x. The bearing 61 is a so-called sliding bearing.

[0022] The impeller 62 is fixed to the bearing 61. The impeller 62 has a cylindrical portion 64, a base 65, and a plurality of blades 66. The impeller 62 is integrally formed by injection molding from a thermoplastic resin material, such as PPS (polyphenylene sulfide). The cylindrical portion 64 is formed in a generally cylindrical shape with axis x as the center. The bearing 61 is fixed inside the cylindrical portion 64. The base 65 is attached to the upper end of the cylindrical portion 64. The base 65 is formed in a disc shape with axis x as the center. A plurality of blades 66 rise upward from the upper surface of the base 65.

[0023] As shown in Figure 3, each blade 66 extends in a curved manner from its inner end to its outer end. In this example, when viewed from above, each blade 66 extends counterclockwise in the radial direction from the inner end to the outer end. Thus, all the blades 66 are arranged in a spiral shape. As shown in Figure 2, the height of the upper end of each blade 66, defined in the axial direction, decreases, for example, from the inner end to the outer end of the blade 66. In other words, the height of each blade 66 may differ between the inner and outer ends, and more preferably, the height of the inner end of each blade 66 may be higher than the height of the outer end.

[0024] Figure 4 is a cross-sectional view along line 4-4 in Figure 2. Referring to both Figures 2 and 4, the magnet 63 is fixed to the outer circumferential surface of the cylindrical portion 64 below the base 65. In this example, the magnet 63 is formed in a cylindrical shape centered on axis x. The magnet 63 is, for example, a permanent magnet. In the magnet 63, a region magnetized as the south pole and a region magnetized as the north pole are defined in the circumferential direction. In the rotor 6, the base 65 and the blades 66 are housed in the first space S1, and the magnet 63 is housed in the second space S2. The outer circumferential surface of the magnet 63 faces the inner circumferential surface of the inner wall 42 of the housing 4.

[0025] The pump device 1 includes an annular stator 7 facing the rotor 6 in the radial direction. The stator 7 is arranged in the annular space between the inner wall 42 and the outer wall 44 and is fixed, for example, to the outer circumferential surface of the inner wall 42 or the inner circumferential surface of the outer wall 44. The stator 7 has a stator core 71, a plurality of coils 72, and an insulator 73. The stator core 71 is formed from a laminate of a plurality of thin plates stacked in the axial direction. The laminate is formed from a magnetic material. The coils 72 are windings formed from, for example, copper wire. The insulator 73 electrically insulates the stator core 71 from the plurality of coils 72. The insulator 73 is formed from an insulating material, for example, a resin material.

[0026] The stator core 71 has an annular portion 74, a plurality (12 in this example) of magnetic pole portions 75, and spokes 76 connecting the annular portion 74 to each magnetic pole portion 75. The annular portion 74 is defined in an annular shape around an axis x. The annular portion 74 is fixed, for example, to the inner circumferential surface of the outer wall 44 of the housing 4. Each spoke 76 protrudes inward from the inner circumferential surface of the annular portion 74. Each magnetic pole portion 75 faces the outer circumferential surface of each magnet 63 with a predetermined magnetic gap, with the inner wall 42 of the housing 4 in between. In this way, the stator 7 faces the rotor 6 in the radial direction. The windings of the coil 72 are wound around the insulator 73 that covers each magnetic pole portion 75. The number of magnetic pole portions 75 may be any number, such as 9 or 18. The number of poles of the rotor 6 can also be changed in accordance with the change in the number of magnetic pole portions 75.

[0027] Returning to Figure 2, a circuit board 81 is housed in the space formed by the bottom plate 41 and outer wall 44 of the housing 4 and the bottom plate 51 of the case 5. The circuit board 81 is formed in the shape of a flat plate that extends along a plane perpendicular to the axis x. In one example, the circuit board 81 may be fixed to the inner surface of the outer wall 44 of the housing 4. Multiple electronic components 82 are mounted on the top and bottom surfaces of the circuit board 81. These electronic components 82 include, for example, field-effect transistors (FETs) and capacitors. The circuit board 81 is electrically connected to the coil 72 of the stator 7 by, for example, one or more connection terminals 83 mounted on the circuit board 81. The circuit board 81 may also have a communication circuit (not shown) mounted on it for communication with the outside or inside of the pump device 1. In this case, the circuit board 81 may communicate with, for example, an ECU (Electronic Control Unit) of an automobile through the communication circuit to control the operation of the pump device 1 from the outside. Note that the term "circuit board 81" includes the meaning of a control board.

[0028] Furthermore, the circuit board 81 is electrically connected to a connector 84. One or more terminals 85 are used for the connection. In one example, the connector 84 is integrally formed with the outer wall 44 of the housing 4. Current and signals are supplied to the circuit board 81 from an external device via this connector 84. Similarly, current is supplied from the circuit board 81 to the coil 72 via the connection terminal 83. In this example, the connector 84 is located within a notch 55 formed in the outer wall 44 of the housing 4. Thus, the connector 84 is exposed to the outside within the notch 55.

[0029] Figure 5 is a partially enlarged cross-sectional view along the line 5-5 in Figure 1. Figure 6 is a further enlarged cross-sectional view of a portion of Figure 5. Referring together to Figures 2, 3, 5, and 6, an elastic member 91 is sandwiched between the housing 4 and the case 5. The elastic member 91 is a sealing member such as an O-ring formed in a continuous annular shape around an axis x. That is, the cross-section of the elastic member 91 along a virtual plane containing the axis x is formed to be approximately circular. The elastic member 91 is formed from an elastic material such as fluororubber (FKM), ethylene propylene diene rubber (EPDM), or silicone rubber (VMQ).

[0030] As shown in Figures 5 and 6, the outer wall 44 of the housing 4 has a main body portion 44a and an extended portion 44b. Both the main body portion 44a and the extended portion 44b are formed in a cylindrical shape centered on axis x. The extended portion 44b constitutes the lower end, i.e., the lower end 44c, of the main body portion 44a in the axial direction. The outer circumferential surface 44d of the main body portion 44a is formed from a tapered surface that decreases in diameter (radial dimension) from top to bottom in the axial direction. On the other hand, the inner circumferential surface 52a of the side wall 52 of the case 5 is formed from a cylindrical surface centered on axis x. At the upper end of the side wall 52, the inner circumferential surface 52a of the side wall 52 and the outer circumferential surface 44d of the main body portion 44a are in contact with each other along a line.

[0031] The size (dimension) of the radial gap between the outer circumferential surface 44d of the main body portion 44a and the inner circumferential surface 52a of the side wall 52 increases from the top to the bottom in the axial direction. The extension portion 44b extends downward along the inner circumferential surface of the main body portion 44a. The thickness (dimension) of the radial extension portion 44b is similarly set to be smaller than the thickness (dimension) of the radial main body portion 44a. In this way, the extension portion 44b forms an annular groove 44e at the lower end 44c of the outer wall 44. The groove 44e is formed by the lower end surface 44f of the main body portion 44a and the outer circumferential surface 44g of the extension portion 44b. The lower end surface 44f is formed in an annular shape centered on axis x. The outer circle 44g is formed from a cylindrical surface centered on axis x. Here, the groove 44e does not have to be a continuous annular shape, and may be formed from a single arc-shaped groove portion extending in the circumferential direction, or it may be formed from a plurality of arc-shaped groove portions extending in the circumferential direction arranged in the circumferential direction.

[0032] On the other hand, the case 5 has an annular projection 56 that spans the bottom plate 51 and the side wall 52. The projection 56 is integrally formed on the upper surface of the bottom plate 51, i.e., the bottom surface 51a, and the inner circumferential surface 52a of the side wall 52. The projection 56 has an annular stepped surface 56a defined along a plane perpendicular to the axis x. The projection 56 has an annular stepped surface 56a facing upward in the axial direction and a cylindrical inner circumferential surface 56b facing inward in the radial direction. In this example, the stepped surface 56a faces the lower end surface 44f of the main body 44a in the axial direction. The inner circumferential surface 56b faces the outer circumferential surface 44g of the extending portion 44b in the radial direction. Here, the projection 56 does not have to be a continuous annular shape, and may be formed from a single arc-shaped projection extending in the circumferential direction, or it may be formed by a plurality of arc-shaped projections extending in the circumferential direction arranged in the circumferential direction.

[0033] The elastic member 91 is sandwiched between the groove 44e of the housing 4 and the case 5. Specifically, it is sandwiched between the lower end surface 44f of the main body portion 44a and the outer peripheral surface 44g of the extended portion 44b, and between the inner peripheral surface 52a of the side wall 52 and the stepped surface 56a of the protruding portion 56. In this example, the elastic member 91 causes the outer peripheral surface 44d of the main body portion 44a and the inner peripheral surface 52a of the side wall 52 to face each other radially with a gap between them. Also, the elastic member 91 causes the outer peripheral surface 44g of the extended portion 44b and the inner peripheral surface 52a of the side wall 52 to face each other radially with a gap between them, and the outer peripheral surface 44g of the extended portion 44b and the inner peripheral surface 56b of the protruding portion 56 to face each other radially with a gap between them.

[0034] Furthermore, an annular lower end surface 44h is formed at the lower end of the extended portion 44b, facing downward in the axial direction. This lower end surface 44h faces the bottom surface 51a of the bottom plate 51 of the case 5, which faces upward in the axial direction, with a gap between them. In this way, a gap is formed between the outer wall 44 of the housing 4 and the bottom plate 51 and side walls 52 of the case 5 in both the axial and radial directions. Note that, as long as the elastic member 91 is positioned within the annular groove 44e, the outer circumferential surface 44g of the extended portion 44b does not have to face the inner circumferential surface 56b of the protrusion 56 in the radial direction. That is, the extended portion 44b does not have to extend axially below the stepped surface 56a of the protrusion 56.

[0035] On the other hand, the upper surfaces of the side wall 52 and flange 54 of case 5 support the lower surface of the flange 45 of housing 4. In this example, the upper surfaces of the side wall 52 and flange 54 and the lower surface of flange 45 are in surface contact with each other. As described above, flange 45 is sandwiched and fixed between the outer peripheral end of the main body 31 of cover 3 and flange 54 of case 5. With this configuration, the outer wall 44 of housing 4 is fixed with high rigidity by cover 3 and case 5. On the other hand, the lower end 44c of the outer wall 44 is formed as a free end by axial and radial gaps. Therefore, the lower end 44c of the main body 44a is supported by the elastic member 91 so that it can be displaced relative to case 5 in the axial and radial directions.

[0036] In this pump device 1, when current is supplied to the coil 72 from an external device, the rotor 6 rotates clockwise around the axis x due to the magnetic interaction between the coil 72 and the magnet 63. This rotation causes multiple blades 66 to generate a flow of coolant along the axial direction, from the inlet 34 to the first space S1. The coolant flows radially outward, passing between circumferentially adjacent blades 66, 66, and then flows clockwise circumferentially along the inner surface of the cover 3 body 31. After that, it flows out from the inner surface of the body 31 through the outlet 33 to the outside of the casing 2 from the outlet 35. In this way, the coolant is pumped, for example, to a drive source.

[0037] When the pump device 1 is driven, it is conceivable that, for example, the rotation center of the rotor 6 may be radially offset from the axis x that coincides with the central axis of the shaft 47. Such rotation of the rotor 6 can cause an imbalance in the rotation of the rotor 6, i.e., the impeller 62, and cause the shaft 47 to vibrate. Such vibrations are ultimately transmitted from the shaft 47 to the housing 4. In addition, for example, the supply of current to the coil 72 wound around the stator core 71 can cause magnetic vibrations in the stator core 71. Similar to the case of an imbalance in the impeller 62, such vibrations are ultimately transmitted from the stator core 71 to the housing 4.

[0038] The aforementioned vibrations are transmitted in the housing 4 from the bottom plate 41, inner wall 42, and top plate 43 to the outer wall 44. An elastic member 91 is sandwiched between the lower end 44c of the main body portion 44a of the outer wall 44 and the bottom plate 51 and side wall 52. The elastic member 91 can tolerate displacement of the outer wall 44 due to vibration in the axial and radial directions. As a result, vibrations transmitted to the housing 4 are dampened by the elastic member 91. Therefore, the transmission of vibrations from the outer wall 44 to the bottom plate 51 and side wall 52, i.e., the case 5, is suppressed. For example, the transmission of vibrations between the housing 44 and the mounting object attached via the bracket portion 53 is suppressed. In this way, quietness can be ensured in the environment in which the pump device 1 is incorporated.

[0039] As described above, in the pump device 1, the housing 4 is supported so as to be displaceable relative to the case 5 in the axial and radial directions by an elastic member 91 sandwiched between the housing 4 and the case 5. As a result, vibrations transmitted to the housing 4 are dampened by the elastic member 91. In this way, vibrations of the pump device 1 can be suppressed. The elastic member 91 is sandwiched between an annular groove 44e at the lower end 44c of the main body portion 44a of the outer wall 44 and a protruding portion 56 of the bottom plate 51 and the side wall 52. Specifically, the elastic member 91 is sandwiched between the lower end surface 44f and the stepped surface 56a which face each other in the axial direction and the outer peripheral surface 44g and the inner peripheral surface 52a which face each other in the radial direction. With this configuration, the elastic member 91 can be held within the annular groove 44e. In addition, since the elastic member 91 can seal the space between the housing 4 and the case 5, water ingress into the housing 4 and the case 5 can be prevented.

[0040] In the pump device 1 described above, the housing 4 is housed within the case 5. The case 5 has one or more bracket portions 53 formed thereon for mounting to an object. As a result, even if the shape of the bracket portion 53 needs to be changed due to a change in the object to be mounted, only the specifications of the bracket portion 53 on the case 5 need to be changed. In other words, the shape of the housing 4 does not need to be changed. Therefore, compared to, for example, the case where the housing 4 and the case 5 are integrally formed with each other, there is no cost for changing the shape of the housing 4. In this way, a highly versatile pump device 1 can be provided.

[0041] In the above-described pump device 1, the outer peripheral surface 44d of the main body portion 44a was formed from a tapered surface whose diameter (dimension) decreases from the upper side to the lower side in the axial direction. Instead of this, the inner peripheral surface 52a of the side wall 52 of the case 5 may be formed from a tapered surface whose diameter (dimension) increases from the upper side to the lower side in the axial direction. In this case, the outer peripheral surface 44d of the main body portion 44a may be formed from a cylindrical surface centered on the axis x. In forming this tapered surface, the housing 4 is, for example, forcibly removed from the mold during molding. On the other hand, when the outer peripheral surface 44d of the main body portion 44a is formed from the above-described tapered surface, this taper can be used as the draw taper during molding of the housing 4.

[0042] As described above, the present invention has been described through the above-described embodiments, but the technical scope of the present invention is not limited to the scope described in the above-described embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above-described embodiments. It is clear from the description of the claims that forms in which such changes or improvements are made can also be included in the technical scope of the present invention.

[0043] The embodiments described above are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Also, the above-described embodiments do not limit the objects to which the present invention is applied, and the present invention can include any object as its application target. Each component included in the above-described embodiments, as well as its arrangement, material, conditions, shape, size, etc. are not necessarily limited to those illustrated and can be changed as appropriate.

[0044] For example, the present invention includes differences that occur in the implementation of manufacturing tolerances and the like. Also, within a technically consistent range, the components shown in different embodiments can be partially replaced or combined with each other. Also, each configuration can be appropriately and selectively combined so as to achieve at least part of the above-described problems and effects.

[0045] 1 Pump device, 2 Casing, 3 Cover, 31 Main body, 32 Inlet, 33 Outlet, 34 Inlet, 35 Outlet, 36 Protruding part, 37 Holding part, 37a Recess, 38 Spoke, 4 Housing, 41 Bottom plate, 41a Bottomed hole, 42 Inner wall, 43 Top plate, 44 Outer wall, 44a Main body part, 44b Extended part, 44c End (lower end), 44d Outer peripheral surface, 44e Annular groove, 44f Lower end surface, 44g Outer peripheral surface, 44h Lower end surface, 45 Flange, 46 Groove part, 47 Shaft, 5 Case, 51 Bottom plate, 51a Bottom surface, 52 Side wall, 52a Inner peripheral surface, 53 Bracket part, 54 Flange, 55 Recess (notch), 56 Protruding part, 56a Stepped surface, 6 Rotor, 61 Bearing, 62 Impeller, 63 Magnet, 64 Cylinder section, 65 Base, 66 Blades, 7 Stator, 71 Stator core, 72 Coil, 73 Insulator, 74 Annular section, 75 Magnetic pole section, 76 Spoke, 81 Circuit board, 82 Electronic components, 83 Connection terminals, 84 Connector, 85 Terminal, 91 Elastic member, S Internal space, S1 First space, S2 Second space, x axis

Claims

1. A pump device comprising: a rotor having an impeller and a magnet; a housing housing the rotor; a stator fixed to the housing facing the rotor in the radial direction; a case housing the housing; and an elastic member sandwiched between the housing and the case, wherein the housing is supported by the elastic member so as to be displaceable relative to the case in the axial and radial directions.

2. The pump device according to claim 1, wherein in the axial direction, the end of the housing is provided with an annular groove, the elastic member is sandwiched between the annular groove and the case, and the end of the housing is supported so as to be displaceable relative to the case.

3. In the axial direction, the end of the housing has an extended portion having a surface facing the case, in the axial direction, the case has a bottom surface facing the extended portion, and the surface of the extended portion faces the bottom surface with a gap between them, the pump device according to claim 1 or 2.

4. The pump device according to any one of claims 1 to 3, wherein the elastic member forms a gap between the housing and the case, and the gap is formed in the axial direction and the radial direction.

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