CN115539397A

CN115539397A - Pump device

Info

Publication number: CN115539397A
Application number: CN202110733832.4A
Authority: CN
Inventors: 牧俊辉
Original assignee: Nidec Sankyo Corp
Current assignee: Nidec Sankyo Corp
Priority date: 2021-06-30
Filing date: 2021-06-30
Publication date: 2022-12-30

Abstract

A pump device contributes to improving the assembly efficiency of an O-ring provided between a first case and a second case. The pump device of the present invention comprises: a motor having a rotor and a stator; an impeller attached to the rotor; a housing having a first shell and a second shell combined in an axial direction and forming a pump chamber in which the rotor and the impeller are arranged; and an O-ring that surrounds a rotation axis of the rotor and is sandwiched between the first shell and the second shell from both sides in an axial direction, wherein the first shell is formed with an annular groove in which the O-ring is accommodated, and the O-ring elastically abuts against an outer peripheral surface of the annular groove, wherein at least a portion of the outer peripheral surface on an opening side of the annular groove includes a first inclined surface that is inclined toward an outer peripheral side with respect to an axial direction so as to be closer to the opening side of the annular groove.

Description

Pump device

Technical Field

The present invention relates to a pump device.

Background

In water heaters, it is sometimes necessary to use a pump device, which generally comprises: a motor having a rotor and a stator; an impeller mounted to the rotor; a housing having a first casing and a second casing combined in an axial direction to form a pump chamber in which a rotor and an impeller are arranged; and an O-ring that surrounds the rotation axis of the rotor, is sandwiched by the first shell and the second shell from both sides in the axial direction, and is housed by an annular groove formed on the first shell.

In the above-described pump device, the outer diameter of the O-ring before it is accommodated in the annular groove may be larger than the inner diameter of the annular groove (that is, the O-ring elastically abuts against the outer circumferential surface of the annular groove after the O-ring is accommodated in the annular groove), and in manufacturing, it is necessary to reduce the outer diameter of the O-ring, fit the O-ring into the annular groove, and then cover and fix the second housing. As described above, since the outer diameter of the O-ring before being accommodated in the annular groove is larger than the inner diameter of the annular groove, when the O-ring is removed from the annular groove, the O-ring is crushed without being accommodated in the annular groove even if the second case is closed.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pump device that contributes to improvement in assembly efficiency of an O-ring provided between a first casing and a second casing.

In order to achieve the above object, the present invention provides a pump apparatus comprising: a motor having a rotor and a stator; an impeller attached to the rotor; a housing having a first casing and a second casing combined in an axial direction and forming a pump chamber in which the rotor and the impeller are arranged; and an O-ring that surrounds a rotation axis of the rotor and is sandwiched between the first shell and the second shell from both sides in an axial direction, wherein the first shell is formed with an annular groove in which the O-ring is accommodated, and the O-ring elastically abuts against an outer peripheral surface of the annular groove, wherein at least a portion of the outer peripheral surface on an opening side of the annular groove includes a first inclined surface that is inclined toward an outer peripheral side with respect to an axial direction so as to be closer to the opening side of the annular groove.

Incidentally, in the present invention, the directions "axial direction", "circumferential direction", and "radial direction" are all based on the rotation axis of the rotor.

According to the pump apparatus of the present invention, since at least a portion of the outer peripheral surface of the annular groove on the opening side of the annular groove includes the first inclined surface inclined toward the outer peripheral side with respect to the axial direction so as to be closer to the opening side of the annular groove, even if the O-ring is removed from the annular groove by vibration, impact, or the like before the second casing is fixed to the first casing after the O-ring is fitted into the annular groove and the second casing is closed, the O-ring is easily moved toward the bottom of the annular groove along the first inclined surface and returned into the annular groove again when the second casing is fixed, which contributes to improvement in the assembly efficiency of the O-ring and ensures the sealing property between the first casing and the second casing by the O-ring.

Further, in the pump apparatus of the present invention, it is preferable that the second housing has an annular projection which enters the annular groove and presses the O-ring.

According to the pump apparatus of the present invention, the second casing has the annular projection which enters the annular groove and presses the O-ring, and therefore, the amount of compression of the O-ring is facilitated to be increased, thereby further ensuring the sealing property between the first casing and the second casing.

In the pump device according to the present invention, it is preferable that at least a portion of the outer peripheral surface of the annular projection on the bottom side of the annular groove is a second inclined surface inclined to the inner peripheral side toward the bottom side of the annular groove in the axial direction.

According to the pump device of the present invention, at least a portion of the outer peripheral surface of the annular projection on the bottom side of the annular groove is the second inclined surface inclined to the inner peripheral side with respect to the axial direction toward the bottom side of the annular groove, and therefore, the first housing and the second housing are easily automatically aligned with each other by the engagement of the first inclined surface and the second inclined surface.

In the pump device according to the present invention, it is preferable that a tip end of the annular projection is located closer to a bottom of the annular groove than an inner circumferential end of the first inclined surface in an axial direction.

According to the pump apparatus of the present invention, the tip of the annular projection is closer to the bottom of the annular groove than the inner peripheral end of the first inclined surface in the axial direction, and therefore, the amount of compression of the O-ring is further increased, and the sealing property between the first casing and the second casing is further ensured.

In the pump device according to the present invention, it is preferable that the second inclined surface is inclined at the same angle as the first inclined surface with respect to the axial direction.

According to the pump apparatus of the present invention, since the angle at which the second inclined surface is inclined with respect to the axial direction is the same as the angle at which the first inclined surface is inclined with respect to the axial direction, the movement of the second inclined surface can be smoothly guided by the first inclined surface, and the assembly efficiency can be improved.

In the pump device according to the present invention, it is preferable that an inner peripheral surface of the annular groove and an inner peripheral surface of the annular protrusion constitute a positioning portion that performs positioning between the first casing and the second casing in a radial direction and/or a circumferential direction.

According to the pump apparatus of the present invention, the inner peripheral surface of the annular groove and the inner peripheral surface of the annular protrusion constitute the positioning portion that performs positioning between the first casing and the second casing in the radial direction and/or the circumferential direction, and therefore, contribute to improvement in assembly efficiency.

In the pump device of the present invention, it is preferable that an outer circumferential end and/or an inner circumferential end of the first inclined surface is a rounded portion.

According to the pump device of the present invention, the outer peripheral end portion and/or the inner peripheral end portion of the first inclined surface forms the rounded portion, and therefore, when the first casing and the second casing are assembled, it is possible to help prevent the second casing and the O-ring from being caught by the outer peripheral end portion of the first casing, or to suppress friction of the O-ring due to contact with the outer peripheral end portion and/or the inner peripheral end portion of the first inclined surface.

In the pump device according to the present invention, it is preferable that the main body or the entire contour line of the first inclined surface cut in the axial direction is a straight line inclined at an angle of 10 ° or more with respect to the axial direction.

According to the pump device of the present invention, since the body or the whole of the contour line of the first inclined surface cut in the axial direction is a straight line inclined at an angle of 10 ° or more with respect to the axial direction, when the O-ring is detached from the annular groove by vibration, impact, or the like before the second housing is fixed to the first housing, the O-ring is easily and reliably moved along the first inclined surface toward the bottom of the annular groove and returned into the annular groove again when the second housing is fixed.

In the pump device according to the present invention, it is preferable that the outer peripheral surface of the annular groove includes a parallel surface which is continuous with an inner peripheral end portion of the first inclined surface and extends in parallel with the axial direction, and the O-ring abuts against the parallel surface in the radial direction and abuts against a bottom portion of the annular groove in the axial direction.

According to the pump device of the present invention, since the outer peripheral surface of the annular groove includes the parallel surface that is continuous with the inner peripheral side end portion of the first inclined surface and extends parallel to the axial direction, and the O-ring abuts against the parallel surface in the radial direction and abuts against the bottom portion of the annular groove in the axial direction, after the O-ring is fitted into the annular groove with its outer diameter reduced, the O-ring is less likely to come out of the annular groove than in the case where the O-ring abuts against the first inclined surface, and further, the sealing property between the first casing and the second casing can be ensured by the O-ring abutting against the parallel surface and the bottom portion of the annular groove at the same time.

In the pump device according to the present invention, it is preferable that the annular groove has an axial depth larger than an axial dimension of a cross section of the O-ring taken in the axial direction.

In the pump device of the present invention, it is preferable that the first casing cover at least a part of the stator, and the second casing is formed with a fluid inlet and a fluid outlet which communicate with the pump chamber.

(effect of the invention)

According to the present invention, at least a portion of the outer peripheral surface of the annular groove on the opening side of the annular groove includes the first inclined surface inclined toward the outer peripheral side with respect to the axial direction so as to be closer to the opening side of the annular groove, and therefore, even if the O-ring is removed from the annular groove by vibration, impact, or the like before the second housing is fixed to the first housing after the O-ring is fitted into the annular groove and the second housing is closed, the O-ring is easily moved toward the bottom of the annular groove along the first inclined surface and returned into the annular groove again when the second housing is fixed, which contributes to improvement in the assembly efficiency of the O-ring and ensures sealing performance between the first housing and the second housing by the O-ring.

Drawings

Fig. 1 is a perspective view schematically showing a pump device according to an embodiment of the present invention.

Fig. 2 is a side sectional view schematically showing a pump device according to an embodiment of the present invention when the pump device is cut in an axial direction.

Fig. 3 is a partially enlarged view of fig. 2.

Fig. 4 is a partial side sectional view schematically showing a pump device according to a modification of the present invention, taken along an axial direction.

(symbol description)

1. Pump device

10. Motor with a stator having a stator core

11. Rotor

111. Cylindrical part

112. Magnet body

12. Stator

121. Stator core

122. Coil

13. Shaft part

20. Impeller

21. Base part

22. Cover part

23. Blade

30. Shell body

31. First shell

311. Cylinder part

3111. Annular groove

312. Bottom part

3121. First bearing part

32. Second shell

321. Barrel part

3211. Annular protrusion

322. Top part

323. Fluid suction pipe

324. Fluid discharge pipe

325. Second bearing part

33. Third shell

331. Connecting part

40 O-shaped ring

50. Circuit board

60. Screw nail

TP1 first inclined plane

Outer peripheral end of TP1a first inclined surface

Inner peripheral end of TP1b first inclined surface

Parallel surface of PP

TP2 second inclined plane

CP connecting surface

IL fluid inlet

OL fluid outlet

CB pump chamber

L axis of rotation

Detailed Description

Next, a pump device according to the present invention will be described with reference to fig. 1 to 3, in which fig. 1 is a perspective view schematically showing a pump device according to an embodiment of the present invention, fig. 2 is a side sectional view schematically showing a pump device according to an embodiment of the present invention when the pump device is cut in an axial direction, and fig. 3 is a partially enlarged view of fig. 2.

(integral construction of Pump device)

As shown in fig. 1 and 2, the pump apparatus 1 includes: a motor 10, the motor 10 having a rotor 11 and a stator 12; an impeller 20, the impeller 20 being attached to the rotor 11; a housing 30 having a first casing 31 and a second casing 32 which are combined in an axial direction (extending direction of a rotation axis L of the rotor 11) and form a pump chamber CB in which the rotor 11 and the impeller 20 are arranged; and an O-ring 40 surrounding the rotation axis L of the rotor 11 and sandwiched between the first casing 31 and the second casing 32 from both sides in the axial direction, wherein an annular groove 3111 for accommodating the O-ring 40 is formed in the first casing 31, and the O-ring 40 elastically abuts against the outer peripheral surface of the annular groove 3111 (the outer diameter of the O-ring 40 before being accommodated in the annular groove 3111 is larger than the inner diameter of the annular groove 3111).

Here, as shown in fig. 1 and 2, the housing 31 is formed with a fluid inlet IL and a fluid outlet OL, and when the pump device 1 is operated, the impeller 20 is rotated by the driving of the motor 10 to suck a fluid (for example, water) into the pump chamber CB from the fluid inlet IL, pressurize the fluid, and discharge the fluid from the fluid outlet OL.

(Structure of case)

As shown in fig. 2, the housing 30 includes a third housing 33 in addition to the first housing 31 and the second housing 32, the first housing 31, and the third housing 33 are stacked and assembled in order in the axial direction.

As shown in fig. 2, the first case 31 covers at least a part of the stator 12, and is made of, for example, bulk molding compound. The first case 31 has a bottomed cylindrical shape as a whole, and includes a cylindrical portion 311 and a bottom portion 312. The cylinder 311 surrounds the rotor 11 from the outer peripheral side with a gap therebetween, the stator 12 is embedded in the cylinder 311, and an annular groove 3111 for accommodating the O-ring 40 is formed in an end portion (specifically, an outer peripheral side portion of the end portion) on one side (Z1 direction side in the illustrated example) in the axial direction of the cylinder 311. The bottom portion 312 closes the opening on the other side (the Z2 direction side in the illustrated example) in the axial direction of the cylinder portion 311, and a first bearing portion 3121 is formed at the center of the bottom portion 312.

As shown in fig. 2, the second casing 32 overlaps the first casing 31 from one side in the axial direction to enclose a pump chamber CB together with the first casing 31. As shown in fig. 1 and 2, the second casing 32 has a funnel shape as a whole, and includes a cylindrical portion 321, a top portion 322, a fluid suction pipe 323, and a fluid discharge pipe 324. The cylinder 321 surrounds the impeller 20 from the outer peripheral side with a gap therebetween, and an end portion on the other side in the axial direction of the cylinder 321 has an annular protrusion 3211 protruding toward the first casing 31 side in the axial direction. The top portion 322 extends from one end portion of the cylindrical portion 321 in the axial direction toward the inner peripheral side. The fluid suction pipe 323 extends from the inner circumferential end of the top portion 322 toward one side in the axial direction, is penetrated by the rotation axis L of the rotor 11, and constitutes a fluid inlet IL. The fluid discharge pipe 324 extends from the cylindrical portion 321 to the outer peripheral side substantially along a tangent line of a circle centered on the rotation axis of the impeller 20 (coinciding with the rotation axis of the rotor 11 in the illustrated example), and constitutes a fluid outlet OL. The second shell 32 also has a second bearing portion 325, and the second bearing portion 325 extends from the inner circumferential side end portion of the top portion 322 toward the other side in the axial direction.

Further, as shown in fig. 1 and 2, the third shell 33 covers the second shell 32 from the other side in the axial direction. A circuit board 50 is disposed between the second case 32 and the third case 13. The third housing 33 has a disk shape, and a plurality of connection portions 331 connected to an external device are formed on an outer peripheral portion of the third housing 33.

Further, as shown in fig. 1 and 2, the second case 32, the first case 31, and the third case 33 are connected together by screws 60.

(construction of impeller)

As described above, the impeller 20 includes the base 21, the cover 22, and the plurality of blades 23.

As shown in fig. 2, the base portion 21 has a disk shape whose thickness direction substantially coincides with the axial direction, and a through hole through which the second bearing portion 325 passes is formed in the center of the base portion 21.

As shown in fig. 2, the lid portion 22 is formed in a disc shape having a thickness direction aligned with the axial direction, and faces the base portion 21 at a distance from the axial direction. Similarly to the base 21, a through hole is formed in the center of the cover 22, and the second bearing 325 is inserted through the through hole.

Further, as shown in fig. 2, the blade 23 extends from the cover 22 to the base 21 in the axial direction. The vanes 23 are formed integrally with the cover 22 and are joined together with the base 21, for example, by ultrasonic welding. The blades 23 extend from the inner circumferential side to the outer circumferential side of the impeller 20 to the vicinity of the outer circumferential edge of the impeller 20. The plurality of blades 23 are arranged at intervals in the circumferential direction, and passages through which fluid flows are formed between circumferentially adjacent blades 23.

(Structure of Motor)

As described above, the motor 10 has the rotor 11 and the stator 12.

As shown in fig. 2, the rotor 11 is rotatably supported by the shaft 13 with respect to the stator 12. One end of the shaft portion 13 is supported by the first bearing portion 3121, and the other end of the shaft portion 13 is supported by the second bearing portion 325. The rotor 11 has a cylindrical portion 111 and a magnet 112. The cylindrical portion 111 surrounds the shaft portion 13 from the outer peripheral side, is provided coaxially with the impeller 20, and is connected to the impeller 20 at one side in the axial direction (the Z1 direction side in the illustrated example). The magnet 112 is provided on the outer peripheral side of the cylindrical portion 111.

Further, as shown in fig. 2, the stator 12 has a stator core 121 and a coil 122. The stator core 121 is opposed to the magnet 112 of the rotor 11 at an interval on the outer peripheral side, and includes an annular core back portion and pole teeth extending radially inward from the core back portion. The coil 122 is wound around the pole teeth of the stator core 121 with an insulator interposed therebetween, and is electrically connected to the circuit board 50.

(sealing Structure between first case and second case)

As described above, the O-ring 40 is provided between the first and

second cases

31 and 32 in the axial direction, and the O-ring 40 is accommodated in the annular groove 3111 formed in the first case 31 and elastically contacts the outer peripheral surface of the annular groove 3111.

As shown in fig. 3, a portion of the outer peripheral surface of the annular groove 3111 on the opening side (Z1 direction side in the illustrated example) of the annular groove 3111 includes a first inclined surface TP1, and the first inclined surface TP1 is inclined toward the outer peripheral side with respect to the axial direction so as to be closer to the opening side (Z1 direction side in the illustrated example) of the annular groove 3111. The outer circumferential end TP1a and the inner circumferential end TP1b of the first inclined surface TP1 form rounded portions, respectively. The first inclined surface TP1 extends from an end portion of the outer peripheral surface of the annular groove 3111 on the opening side of the annular groove 3111 toward the bottom of the annular groove 3111, and the axial dimension of the first inclined surface TP1 is about half of the axial dimension of the annular groove 3111. The main body of the contour line of the first inclined surface TP1 cut in the axial direction is a straight line inclined at an angle of 10 ° or more with respect to the axial direction. The outer peripheral surface of the annular groove 3111 further includes a parallel surface PP that is continuous with the inner peripheral end of the first inclined surface TP1 and extends parallel to the axial direction. The O-ring 40 radially abuts against the parallel surface PP and axially abuts against the bottom of the annular groove 3111. The axial depth of the annular groove 3111 is larger than the axial dimension of the cross section of the O-ring 40 taken in the axial direction.

Further, as shown in fig. 3, the second housing 32 has an annular projection 3211, and the annular projection 3211 enters the annular groove 3111 and presses the O-ring 40. Specifically, in the second case 32, the other end portion (Z2 direction side in the illustrated example) in the axial direction of the tube portion 321 has an annular projection 3211 that projects toward the first case 31 side in the axial direction, the tip end (Z2 direction side end portion in the illustrated example) of the annular projection 3211 is closer to the bottom of the annular groove 3111 than the inner circumferential end portion of the first inclined surface TP1 in the axial direction, and the tip end of the annular projection 3211 presses the O-ring 40 to elastically contact the bottom of the annular groove 3111. The outer peripheral surface of the annular projection 3211 is a parallel surface extending parallel to the axial direction.

As shown in fig. 3, a portion of the first case 31 on the outer peripheral side of the annular groove 3111 and a portion of the second case 32 on the outer peripheral side of the annular projection 3211 constitute positioning portions for positioning between the first case 31 and the second case 32 in the axial direction. The portion of the first shell 31 on the outer circumferential side of the annular groove 3111 is a plane perpendicular to the axial direction, and the portion of the second shell 32 on the outer circumferential side of the annular projection 3211 is also a plane perpendicular to the axial direction, and is in contact with the portion of the first shell 31 on the outer circumferential side of the annular groove 3111 from the axial direction.

Further, as shown in fig. 3, an inner peripheral surface of the annular groove 3111 and an inner peripheral surface of the annular projection 3211 constitute positioning portions that position between the first and

second shells

31 and 32 in the radial direction and/or the circumferential direction. The inner circumferential surface of the annular groove 3111 extends in the axial direction, and the inner circumferential surface of the annular projection 3211 also extends in the axial direction and abuts against the inner circumferential surface of the annular groove 3111 from the inner circumferential side. An inner circumferential surface of the annular groove 3111 and an inner circumferential surface of the cylindrical portion 311 are connected via a connection surface CP, an inner circumferential side portion of which is an inclined surface inclined with respect to the axial direction and which is further away from the second shell 31 toward the inner circumferential side, and an outer circumferential side portion of which is a chamfered surface, and a portion of which between the inner circumferential side portion and the outer circumferential side portion is a plane perpendicular to the axial direction.

As shown in fig. 3, the bottom surface of the annular groove 3111 is a plane perpendicular to the axial direction.

(main effect of the present embodiment)

According to the pump apparatus 1 of the present embodiment, since the portion of the outer peripheral surface of the annular groove 3111 on the opening side of the annular groove 3111 includes the first inclined surface TP1, and the first inclined surface TP1 is inclined toward the outer peripheral side with respect to the axial direction so as to be closer to the opening side of the annular groove 3111, even if the O-ring 40 is detached from the annular groove 3111 by vibration, impact, or the like before the second casing 32 is fixed to the first casing 31 by, for example, the screw 60 or the like, after the O-ring 40 is reduced in outer diameter size and fitted into the annular groove 3111 and the second casing 32 is closed, the O-ring 40 is easily moved toward the bottom of the annular groove 3111 along the first inclined surface TP1 and returned into the annular groove 3111 again when the second casing 32 is fixed, which contributes to improving the assembly efficiency of the O-ring 40 and ensures the sealing between the first casing 31 and the second casing 32 by the O-ring 40, thereby also contributing to avoiding that the O-ring 40 is caught between the outer peripheral edge of the opening of the annular groove 3111 on the first casing 31 and the second casing 32 from being sealed well.

The present invention is described above by way of example with reference to the accompanying drawings, and it is to be understood that the specific implementations of the present invention are not limited to the above-described embodiments.

For example, in the above embodiment, the first shell 31 covers at least a part of the stator 12, and the second shell 32 is formed with the fluid inlet IL and the fluid outlet OL, but not limited thereto, and may be formed such that the first shell 31 is formed with the fluid inlet IL and the fluid outlet OL, and the second shell 32 covers at least a part of the stator 12.

In the above embodiment, the outer peripheral surface of the annular projection 3211 is a parallel surface extending parallel to the axial direction, but the present invention is not limited to this, and as shown in fig. 4, at least a portion of the outer peripheral surface of the annular projection 3211 on the bottom side of the annular groove 3111 may be formed as a second inclined surface TP2 (of course, the entire outer peripheral surface of the annular projection 3211 may be formed as the second inclined surface TP 2), the second inclined surface PT2 may be inclined toward the inner peripheral side toward the bottom side of the annular groove 3111 in the axial direction, and the angle at which the second inclined surface TP2 is inclined in the axial direction may substantially match the angle at which the first inclined surface TP1 is inclined in the axial direction (of course, the angle at which the second inclined surface TP2 is inclined in the axial direction may be different from the angle at which the first inclined surface TP1 is inclined in the axial direction).

In the above embodiment, the outer peripheral surface of the annular groove 3111 includes the parallel surface PP that extends in parallel with the axial direction and is continuous with the inner peripheral end portion of the first inclined surface TP1, but the present invention is not limited to this, and the parallel surface PP may be omitted in some cases.

Further, in the above embodiment, the axial depth of the annular groove 3111 is larger than the axial dimension of the cross section of the O-ring 40 taken along the axial direction, and the tip of the annular projection 3211 is located closer to the bottom of the annular groove 3111 than the inner peripheral end of the first inclined surface TP1 in the axial direction, but the present invention is not limited to this, and the axial depth of the annular groove 3111 may be equal to or less than the axial dimension of the cross section of the O-ring 40 taken along the axial direction, in which case the dimension of the projection of the annular projection 3211 toward the second housing 32 may be reduced, and the annular projection 3211 may be omitted.

In the above embodiment, the outer peripheral end portion TP1a and the inner peripheral end portion TP1b of the first inclined surface TP1 constitute rounded portions, respectively, but the present invention is not limited to this, and the outer peripheral end portion TP1a and the inner peripheral end portion TP1b of the first inclined surface TP1 may be chamfered portions.

In the above-described embodiment and modification, the bodies or the entire outlines of the first inclined surface TP1 and the second inclined surface TP2 cut in the axial direction may be straight lines, but the present invention is not limited thereto, and the bodies or the entire outlines of the first inclined surface TP1 and the second inclined surface TP2 cut in the axial direction may be arcs or continuous broken lines.

It should be understood that the present invention can freely combine the respective components in the embodiments, or appropriately change or omit the respective components in the embodiments within the scope thereof.

Claims

1. A pump apparatus, comprising: a motor having a rotor and a stator; an impeller attached to the rotor; a housing having a first shell and a second shell combined in an axial direction and forming a pump chamber in which the rotor and the impeller are arranged; and an O-ring surrounding a rotation axis of the rotor and sandwiched between the first shell and the second shell from both sides in an axial direction, wherein the first shell has an annular groove in which the O-ring is accommodated, and the O-ring elastically abuts against an outer peripheral surface of the annular groove,

at least a portion of the outer peripheral surface on the opening side of the annular groove includes a first inclined surface,

the first inclined surface is inclined toward the outer peripheral side with respect to the axial direction as the opening side of the annular groove is approached.

2. The pump apparatus of claim 1,

the second housing has an annular protrusion,

the annular protrusion enters the annular groove and presses the O-ring.

3. The pump apparatus of claim 2,

at least a portion of the outer peripheral surface of the annular projection on the bottom side of the annular groove is a second inclined surface,

the second inclined surface is inclined toward the inner peripheral side with respect to the axial direction as the second inclined surface is closer to the bottom of the annular groove.

4. The pump apparatus of claim 2,

the tip of the annular projection is closer to the bottom of the annular groove than the inner peripheral end of the first inclined surface in the axial direction.

5. The pump apparatus of claim 2,

an inner peripheral surface of the annular groove and an inner peripheral surface of the annular protrusion constitute a positioning portion that performs positioning between the first shell and the second shell in a radial direction and/or a circumferential direction.

6. The pump apparatus of claim 1,

the outer peripheral end and/or the inner peripheral end of the first inclined surface forms a rounded portion.

7. The pump apparatus of claim 1,

the main body or the whole of the contour line of the first inclined surface cut along the axial direction is a straight line inclined at an angle of 10 DEG or more with respect to the axial direction.

8. The pump apparatus of claim 1,

an outer peripheral surface of the annular groove includes a parallel surface that is continuous with an inner peripheral side end portion of the first inclined surface and extends parallel to an axial direction,

the O-ring abuts against the parallel surface in the radial direction and abuts against the bottom of the annular groove in the axial direction.

9. The pump apparatus of claim 1,

the axial depth of the annular groove is greater than the axial dimension of the cross section of the O-shaped ring along the axial sectioning direction.

10. The pump apparatus of claim 1,

the first shell covers at least a portion of the stator,

the second housing is formed with a fluid inlet and a fluid outlet communicating with the pump chamber.