Electric pump

Abstract

An electric pump includes a shaft extending in an axial direction, a rotor located outward of the shaft in a radial direction and configured to be rotatable, a stator located outward of the rotor in the radial direction and surrounding the rotor, a pump portion located on one side of the shaft in the axial direction, and a housing including a pump accommodating portion configured to accommodate the pump portion. Furthermore, the pump accommodating portion includes a support portion to support an end portion of the shaft on the one side in the axial direction.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present invention claims priority under 35 U.S.C. § 119 to Japanese Patent Application Nos. 2025-062797 and 2025-062798, filed on Apr. 4, 2025, and U.S. Patent Application No. 63 / 720,904, filed on Nov. 15, 2024, the entire contents of which are hereby incorporated herein by reference.1. Field of the Invention

[0002] The present disclosure relates to an electric pump.2. Background

[0003] There have been known pump devices in which a pump portion is coupled to a motor part and a shaft of the motor part is made into a cantilevered support structure. In this pump device, for example, the shaft is cantilevered and supported in a rotatable state via a sliding bearing on a separation plate where the shaft is held abutted against an end surface of a stator.

[0004] In the cantilevered support structure of the shaft, there is a possibility that the shaft may deflect in a radial direction due to the influence of centrifugal force when a rotor rotates. When the shaft deflects in the radial direction, there is a possibility that the rotor may come into contact with the stator, causing noise generation or a decrease in pump efficiency.SUMMARY

[0005] An electric pump according to an example embodiment of the present disclosure includes a shaft extending in an axial direction, a rotor located outward of the shaft in a radial direction and configured to be rotatable, a stator located outward of the rotor in the radial direction and surrounding the rotor, a pump portion located on one side of the shaft in the axial direction, and a housing including a pump accommodating portion configured to accommodate the pump portion. The pump accommodating portion includes a support portion to support an end portion of the shaft on the one side in the axial direction.

[0006] The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective view of an electric pump according to an example embodiment as viewed from the other side in an axial direction.

[0008] FIG. 2 is a cross-sectional view of the electric pump according to the example embodiment, taken along a center axial line.

[0009] FIG. 3 is a perspective view illustrating a state in which a control unit is removed from the electric pump according to the example embodiment illustrated in FIG. 1.

[0010] FIG. 4 is a perspective view of a first housing according to the example embodiment as viewed from one side in the axial direction.

[0011] FIG. 5 is an exploded perspective view of a partition wall member according to the example embodiment as viewed from the other side in the axial direction.

[0012] FIG. 6 is a perspective view of the partition wall member according to the example embodiment as viewed from the one side in the axial direction.

[0013] FIG. 7 is a partially enlarged view illustrating section A of FIG. 2.

[0014] FIG. 8 is a partially enlarged view illustrating section B of FIG. 2.

[0015] FIG. 9 is a perspective view of the partition wall member according to the example embodiment as viewed from the other side in the axial direction.

[0016] FIG. 10 is a perspective view of a second housing according to the example embodiment in which a pump portion is accommodated, as viewed from the other side in the axial direction.

[0017] FIG. 11 is a perspective view of the second housing according to the example embodiment as viewed from the one side in the axial direction.

[0018] FIG. 12 is an exploded perspective view of the pump portion and the second housing according to the example embodiment, as viewed from the other side in the axial direction.

[0019] FIG. 13 is a partially enlarged view illustrating section C of FIG. 2.

[0020] FIG. 14 is a partially enlarged view illustrating section A of FIG. 13.DETAILED DESCRIPTION

[0021] Hereinafter, an example embodiment of an electric pump 100 of the present disclosure will be described with reference to the accompanying drawings. In each drawing, a center axial line J of the electric pump 100 of the present example embodiment is virtually illustrated. In the description below, an axial direction of the center axial line J is simply referred to as an “axial direction”, a radial direction about the center axial line J is simply referred to as a “radial direction”, and a circumferential direction about the center axial line J is simply referred to as a “circumferential direction”. A Z-axis illustrated in each drawing indicates a direction in which the center axial line J extends.

[0022] Further, in the description of the present example embodiment, in order to facilitate understanding of the configuration of each portion, a direction in which the arrow of the Z-axis is directed (upper sides in the drawings) is referred to as the “other side in the axial direction”. Note that the “other side in the axial direction” may be simply referred to as “upper side”. Further, in the description of the example embodiment, a direction opposite to the direction in which the arrow of the Z-axis is directed is referred to as “one side in the axial direction”. Note that the “one side in the axial direction” may be simply referred to as “lower side”. In the description of the example embodiment, the upper side and the lower side are terms for convenience for describing a relative positional relationship of each portion. The actual arrangement relationship or the like may be an arrangement relationship or the like other than the arrangement relationship or the like indicated by these terms.

[0023] The electric pump 100 of the present example embodiment illustrated in FIG. 1 and FIG. 2 is, for example, a water pump for cooling that feeds water as a fluid (refrigerant), or an oil pump for cooling that feeds oil as a fluid (refrigerant). FIG. 1 is a perspective view of the electric pump 100 as viewed obliquely from the upper side. FIG. 2 is a cross-sectional view of the electric pump 100 taken along the center axial line J.

[0024] The electric pump 100 of the present example embodiment includes a motor part 10, a pump portion 20 located on the one side (lower side) of the motor part 10 in the axial direction, a control unit 30 located on the other side (upper side) of the motor part 10 in the axial direction, and a housing H. The motor part 10, the pump portion 20, and the control unit 30 are accommodated in the housing H made of a metal. The housing H includes a first housing 11 that accommodates the motor part 10, a second housing 21 that accommodates the pump portion 20, and a third housing 31 that accommodates the control unit 30. Hereinafter, configurations of the motor part 10, the pump portion 20, and the control unit 30 will be described in detail.Motor Part 10

[0025] As illustrated in FIG. 2, the motor part 10 includes a shaft 12 located on the center axial line J and extending in a direction of the center axial line J (axial direction), a rotor 13 located outward of the shaft 12 in the radial direction, and a stator 15 surrounding the rotor 13. The motor part 10 is accommodated in a motor accommodating portion 11h (FIG. 4) inside the first housing 11. FIG. 4 is a perspective view of the first housing 11 as viewed from the lower side.

[0026] As illustrated in FIG. 3, the first housing 11 includes an outer shell 11a having a cylindrical shape and an upper portion 11b provided on the upper side of the outer shell 11a. The upper portion 11b is a member having a disk shape. FIG. 3 is a perspective view illustrating a state in which the control unit 30 is removed from the electric pump 100 illustrated in FIG. 1. As illustrated in FIG. 4, the first housing 11 includes a first opening 11k that opens toward the pump portion 20 side. A flange 11m extending outward in the radial direction is formed at an edge portion of the first opening 11k. The flange 11m is formed in the circumferential direction of the edge portion of the first opening 11k. The flange 11m is formed with a first surface 11n facing the pump portion 20 side. The first surface 11n is a flat surface without a step except for a groove for accommodating an O-ring. Further, a plurality of screw holes 11p are formed in the flange 11m. The plurality of screw holes 11p are formed at a predetermined interval in the circumferential direction of the flange 11m.

[0027] As illustrated in FIG. 3, a shaft fixing portion 11c is formed on the upper portion 11b of the first housing 11. An end portion (upper end portion) of the shaft 12 on the other side in the axial direction is fixed to the shaft fixing portion 11c. The shaft fixing portion 11c is composed of a shaft fixing hole h1 formed at a center of the upper portion 11b. As illustrated in FIG. 7, an upper end portion of the shaft fixing hole h1 is expanded as compared with the other end portion of the shaft fixing hole h1, and the expanded portion forms a first stepped portion s1 having an annular shape. FIG. 7 is a partially enlarged view illustrating section A in FIG. 2.

[0028] As illustrated in FIG. 7, a second stepped portion 12a widened into a flange shape is formed at the end portion (upper end portion) of the shaft 12 on the other side in the axial direction. The second stepped portion 12a of the shaft 12 is expanded as compared with other portions of the shaft 12. The shaft 12 is inserted into and fixed to the shaft fixing hole h1. When the shaft 12 is inserted and fixed to the shaft fixing hole h1, the second stepped portion 12a of the shaft 12 faces the first stepped portion s1 in the axial direction. More specifically, the second stepped portion 12a comes into contact with the first stepped portion s1 in the axial direction. With the second stepped portion 12a of the shaft 12 being brought into contact with the first stepped portion s1 in the axial direction, even when a force pulling toward the one side (lower side) in the axial direction acts on the shaft 12, the shaft 12 can be prevented from moving (shifting) toward the one side (lower side) in the axial direction. The shaft 12 is fixed to the shaft fixing portion 11c by press-fitting.

[0029] As illustrated in FIG. 2, the rotor 13 having a cylindrical shape is disposed outward of the shaft 12 in the radial direction so as to surround the shaft 12. The rotor 13 is rotatable about the shaft 12. The rotor 13 includes a rotor core 13a, a magnet 13b, rotor support plates 13c, a rotor support shaft 13d, and a rotor cover 13f. The rotor core 13a is formed by vertically stacking several tens of laminated steel sheets (electromagnetic steel sheets).

[0030] The rotor support plates 13c are located on the upper side and the lower side of the rotor core 13a. The rotor support plates 13c sandwich the magnet 13b and the rotor core 13a from above and below. The rotor cover 13f covers a side surface of the rotor core 13a. The rotor core 13a is separated (waterproofed) from fluid (refrigerant) such as water by the rotor cover 13f and the two rotor support plates 13c. The rotor support shaft 13d has a tubular shape extending in the axial direction. The rotor support shaft 13d is rotatably attached to the shaft 12 via a bearing 14. The bearing 14 is a sliding bearing in the present example embodiment. An impeller main body 20a of the pump portion 20 is connected to a lower end of the rotor support shaft 13d. The rotor support shaft 13d and the impeller main body 20a of the pump portion 20 are connected to each other by press-fitting and welding. Press-fitting allows centering, and welding ensures connection strength. The configurations of the rotor support shaft 13d and the impeller main body 20a of the pump portion 20 will be described below.

[0031] The stator 15 is disposed outward of the rotor 13 in the radial direction so as to surround the rotor 13. The stator 15 is assembled on an inner circumferential surface of the first housing 11 by shrink-fitting. The stator 15 includes a stator core 15a, an insulator 15b attached to the stator core 15a, and a plurality of coils 15c attached to the stator core 15a with the insulator 15b interposed therebetween. The stator core 15a is formed by stacking several tens of laminated steel sheets (electromagnetic steel sheets) punched into ring shapes. A coil winding part for winding each coil 15c is formed on an inner side of the stator core 15a. The coil winding part extends from the stator core 15a toward a central portion.

[0032] The insulator 15b is composed of a protective material such as a resin. The insulator 15b covers a front surface of the stator core 15a. That is, the insulator 15b covers an inner circumferential surface of the stator core 15a having a tubular shape and front surfaces of the respective coil winding parts to protect the coils 15c. The coil 15c is composed of a winding made of a metal such as copper or aluminum. The coil 15c is wound around each coil winding part of the stator core 15a.

[0033] A coil lead wire 15d of the coil 15c is connected to a bus bar assembly 19 located on the upper side of the stator 15. The bus bar assembly 19 is connected to the control unit 30 and supplies three-phase alternating current power from the control unit 30 to each coil 15c. The energization of each coil 15c from the bus bar assembly 19 generates magnetic flux inside each coil 15c. The bus bar assembly 19 will be further described below.

[0034] A partition wall member 16 serving as a seal portion is provided between the rotor 13 and the stator 15. FIG. 5 is a perspective view of the partition wall member 16 as viewed from the upper side. As illustrated, the partition wall member 16 has a shape like an inverted cup, and an upper portion (first partition wall 16a) of the partition wall member 16 is supported by the shaft 12. The partition wall member 16 includes the first partition wall 16a having a disk shape and located on the upper side, a second partition wall 16b having a cylindrical shape and extending downward from an outer circumferential edge portion of the first partition wall 16a, and a third partition wall 16c extending outward from a circumferential edge portion of the second partition wall 16b in the radial direction. A connecting part 16p between the second partition wall 16b and the third partition wall 16c is machined into an arc shape. The partition wall member 16 is formed of a metal or a resin having sealing performance. FIG. 6 is a perspective view of the partition wall member 16 as viewed from the lower side. Note that, although the partition wall member 16 has been described as having a shape like an inverted cup, the partition wall member 16 may be said to have a hat (billed cap) shape.

[0035] A fourth partition wall 16d extending toward the upper side is provided at a circumferential edge portion of the third partition wall 16c. Furthermore, a fixing portion 16e having a flange shape and extending outward in the radial direction is provided to a circumferential edge portion of the fourth partition wall 16d. The first partition wall 16a, the second partition wall 16b, the third partition wall 16c, the fourth partition wall 16d, and the fixing portion 16e form a continuous structure. A plurality of holes 16f through which screws (bolts) are passed are formed in the fixing portion 16e. In the present example embodiment, six holes 16f are formed. The holes 16f are provided outward of the fixing portion 16e in the radial direction.

[0036] As illustrated in FIG. 5, a plurality of reinforcing members 16g connected to an upper surface of the third partition wall 16c are provided on an outer surface of the second partition wall 16b. The reinforcing members 16g are provided at a predetermined interval in the circumferential direction of the second partition wall 16b. The reinforcing member 16g is a reinforcing rib in the present example embodiment. The shape of the reinforcing rib 16g is a right-angled triangle as viewed from the circumferential direction. A portion corresponding to the opposite side of the reinforcing rib 16g is connected to the outer surface of the second partition wall 16b. Further, a portion corresponding to an adjacent side is connected to the upper surface of the third partition wall 16c. A portion corresponding to a right angle is chamfered in accordance with the arc shape of the second partition wall 16b, the third partition wall 16c, and the connecting part 16p. The second partition wall 16b and the third partition wall 16c are connected at a right angle at the connecting part 16p.

[0037] The reinforcing ribs 16g are disposed between the coils 15c constituting the stator 15. The plurality of reinforcing ribs 16g maintain a right-angle connection state of the second partition wall 16b and the third partition wall 16c. In a case in which the partition wall member 16 is made of a metal, the reinforcing ribs 16g are formed of a metal and connected to the partition wall member 16 by welding, bonding, or the like. When the partition wall member 16 is made of a resin, the reinforcing ribs 16g may be formed of a metal or may be formed of a resin. In a case in which the partition wall member 16 is made of a resin and the reinforcing ribs 16g are made of a metal, the reinforcing ribs 16g can be integrally molded and assembled when the partition wall member 16 is molded with a mold. In a case in which the partition wall member 16 is made of a resin and the reinforcing ribs 16g are also made of a resin, the reinforcing ribs 16g can be molded simultaneously with the molding of the partition wall member 16 by a mold, or the reinforcing ribs 16g can be provided as separate members and joined to the partition wall member 16 by welding. The reinforcing ribs 16g made of a metal are disposed near the coils 15c, and thus heat of the coils 15c transmitted through space can be radiated to the fluid located on an inner side of the partition wall member 16. The reinforcing ribs 16g made of a resin can be molded simultaneously with the molding of the partition wall member 16 by a mold, making it possible to reduce cost.

[0038] A through-hole 16h through which the shaft 12 passes is formed in a central portion of the first partition wall 16a. An attachment body 16j having a tubular shape is provided on a circumferential edge portion of the through-hole 16h so as to extend to the upper side from the through-hole 16h. Then, as illustrated in FIG. 7, the shaft 12 is passed through the attachment body 16j and the through-hole 16h, whereby the first partition wall 16a is attached to the shaft 12. FIG. 7 is a partially enlarged view illustrating section A in FIG. 2. With the first partition wall 16a attached to the shaft 12, the first partition wall 16a having a disk shape is located above the rotor 13 so as to extend outward from the shaft 12 in the radial direction, and the first partition wall 16a covers the upper side of the rotor 13 having a cylindrical shape.

[0039] Further, as illustrated in FIG. 2, the second partition wall 16b extending downward from the outer circumferential edge portion of the first partition wall 16a is located between the rotor 13 and the stator 15, and the second partition wall 16b separates the rotor 13 and the stator 15. Furthermore, as illustrated in FIG. 13, the lower side of the stator 15 is covered by the third partition wall 16c and the fourth partition wall 16d, the third partition wall 16c extending outward from a lower circumferential edge portion of the second partition wall 16b. The fourth partition wall 16d is fixed to the first housing 11 by the fixing portion 16e extending outward from the fourth partition wall 16d in a flange shape in the radial direction. FIG. 13 is a partially enlarged view illustrating section C of FIG. 2. That is, the lower side of the partition wall member 16 is fixed to the first housing 11 by the fixing portion 16e.

[0040] As illustrated in FIG. 7, an O-ring attachment groove 16m is formed on an outer circumferential surface of the shaft 12 at a location where the shaft 12 is fitted to the attachment body 16j. An O-ring 16k is attached to the O-ring attachment groove 16m. The O-ring 16k seals an area between the shaft 12 and the attachment body 16j. The partition wall member 16 suitably separates the rotor 13 and the stator 15 from each other, and seals the area so that fluid inside the rotor 13 does not leak to the stator 15 side. The second partition wall 16b does not come into contact with either the rotor 13 or the stator 15. That is, as illustrated in FIG. 8, a gap c1 is formed between the second partition wall 16b and the rotor 13. Further, a gap c2 is formed between the second partition wall 16b and the stator 15. FIG. 8 is a partially enlarged view illustrating section B of FIG. 2.

[0041] As illustrated in FIG. 7, an auxiliary member 17 is disposed between the first partition wall 16a of the partition wall member 16 and the upper portion 11b of the first housing 11. Reference sign f2 in FIG. 7 denotes a lower surface of the auxiliary member 17 (contact surface that comes into contact with the partition wall member 16). The auxiliary member 17 has a disk shape as illustrated in FIG. 5. A through-hole 17a is formed at a center of the auxiliary member 17. The attachment body 16j of the partition wall member 16 is inserted into the through-hole 17a. Reference sign f1 in FIG. 5 denotes a top surface (surface facing upward) of the first partition wall 16a. As illustrated in FIG. 7, the attachment body 16j is inserted into the through-hole 17a, bringing the top surface f1 of the first partition wall 16a and the contact surface f2 of the auxiliary member 17 into contact with each other across the entire surface. FIG. 9 is a perspective view illustrating a state in which the attachment body 16j of the partition wall member 16 is inserted into the through-hole 17a of the auxiliary member 17 (state in which the auxiliary member 17 is assembled on the partition wall member 16).

[0042] Furthermore, as illustrated in FIG. 7, a recess portion 17b having a circular shape is formed in a surface of the auxiliary member 17 on the upper side. The recess portion 17b is formed by a guide wall w1 having an annular shape and located so as to surround the through-hole 17a with the through-hole 17a as a center. The guide wall w1 is a wall extending in a Z direction. A surface f3 surrounded by the guide wall w1 and facing the other side in the axial direction is a surface that receives the tip of a screw 18 (lower end of the screw 18 in FIG. 7). The surface f3 that is the surface that receives the tip of the screw 13 may be referred to as the receiving surface f3. As illustrated in FIG. 7, a space (gap) S having an annular shape is formed around the guide wall w1.

[0043] A protruding portion 11d protruding downward is provided on a surface (lower surface) of the upper portion 11b of the first housing 11 facing downward. The protruding portion 11d is located below the shaft fixing portion 11c. The protruding portion 11d has a circular shaper. The protruding portion 11d includes the shaft fixing hole h1 in a central portion. Then, as illustrated in FIG. 7, the protruding portion 11d having a circular shape is fitted in the recess portion 17b, having a circular shape, of the auxiliary member 17. In the fitting, a gap between the protruding portion 11d and the recess portion 17b in the radial direction is very small. With the protruding portion 11d fitted into the recess portion 17b, the auxiliary member 17 is in a state of not rattling in the radial direction. The protruding portion 11d and the recess portion 17b are in a so-called spigot-and-socket state. Note that, as indicated by a white arrow (two way arrow) in FIG. 7, the auxiliary member 17 is movable in the axial direction (+Z direction and −Z direction) along the protruding portion 11d.

[0044] Further, as illustrated in FIG. 3, a plurality of screw holes 11f penetrating the upper portion 11b of the first housing 11 in the Z direction are formed in the shaft fixing portion 11c of the first housing 11. The plurality of screw holes 11f are formed in the circumferential direction about the shaft fixing hole h1. In the present example embodiment, three screw holes 11f are formed at equal intervals in the circumferential direction. The screw 18 serving as a pressing member is screwed into each screw hole 11f. As illustrated in FIG. 5, the screws 18 are fine screws without heads, such as full thread bolts or plungers, for example, and each screw 18 can, as a whole, be embedded in the screw hole 11f.

[0045] A lower end portion of the screw 18 is machined into a shape with chamfered corners or a hemispherical shape. As illustrated in FIG. 7 and FIG. 9, the lower end portion of the screw 18 protrudes downward from the screw hole 11f, and a lower end surface of the screw 18 comes into contact with the receiving surface f3 of the recess portion 17b of the auxiliary member 17. A hexagonal hole, a star-shaped hole, or the like is formed in the other end portion (upper end) of the screw 18 in the axial direction. A tool such as a hexagonal wrench or a star wrench can be mounted in the hexagonal hole or the star hole. The screw 18 is screwed into the screw hole 11f from the upper side of the shaft fixing portion 11c by using a tool such as a hexagonal wrench. At this time, whether the tip of the screw 18 has come into contact with the receiving surface f3 of the recess portion 17b of the auxiliary member 17 can be determined by detecting a change in a screwing torque of the screw 18, for example. It is also possible to determine whether a contact pressure (pressing force) between the tip (lower end) of the screw 18 and the receiving surface f3 is appropriate by detecting a change in the screwing torque of the screw 18.

[0046] As illustrated in FIG. 2, the space S is formed around the auxiliary member 17. The space S is a space having an annular shape about the shaft 12. The space S is formed by the guide wall w1 of the auxiliary member 17, the upper portion 11b of the first housing 11, the outer shell 11a of the first housing 11, and the other surface (upper surface) of the stator 15 in the axial direction. The bus bar assembly 19 is accommodated at a position outward of the space S in the radial direction, that is, in the vicinity of an inner surface of the outer shell 11a of the first housing 11.

[0047] The bus bar assembly 19 includes an assembly main body 19a having an annular shape and extending along the inner surface of the outer shell 11a of the first housing 11, a coil connecting part 19b, and a substrate-side protruding portion 19c. The coil connecting part 19b and the substrate-side protruding portion 19c are paired. In the present example embodiment, three pairs are provided. The coil connecting part 19b includes a bus bar (conductive rod) connected to the coil lead wires 15d extending from the coils 15c of the stator 15. As illustrated in FIG. 2, the coil connecting part 19b is disposed inward in the radial direction, that is, in the guide wall w1 direction of the auxiliary member 17.

[0048] The coil connecting part 19b is disposed facing inward in the radial direction, and thus a tip side of the coil connecting part 19b overlaps the rotor 13 and the auxiliary member 17 as viewed from the axial direction. With the coil connecting part 19b overlapping the rotor 13 and the auxiliary member 17, it is not necessary to enlarge, in the radial direction, the space S accommodating the coil connecting part 19b. With the coil connecting part 19b and the auxiliary member 17 accommodated in the space S, it is possible to reduce the size of the first housing 11 in the radial direction. The space S is a space formed in the axial direction. The space S is effectively utilized, thereby achieving a reduction in the size of the first housing 11 in the radial direction. Further, the coil connecting part 19b is disposed at a position lower than a height of the guide wall w1 of the auxiliary member 17, making it possible to suppress an increase in the size of the first housing 11 in the axial direction.

[0049] As illustrated in FIG. 2 and FIG. 3, the substrate-side protruding portion 19c is disposed on an inner side of a through-hole 11g formed in the upper portion 11b of the first housing 11. In the present example embodiment, three through-holes 11g are formed in the upper portion 11b of the first housing 11. The substrate-side protruding portion 19c is disposed in each through-hole 11g. The substrate-side protruding portion 19c is provided with a connection terminal 19d connected to the bus bar of the coil connecting part 19b. As illustrated in FIG. 3, the connection terminal 19d protrudes upward from the substrate-side protruding portion 19c. The connection terminal 19d protrudes upward from the substrate-side protruding portion 19c, thereby electrically connecting a tip of the connection terminal 19d to the control unit 30 when the control unit 30 is assembled on the upper portion 11b of the first housing 11.Pump Portion 20

[0050] As illustrated in FIG. 2 and FIG. 13, the pump portion 20 is accommodated in a pump accommodating portion 20h located below the motor part 10. As illustrated in FIG. 10, the pump portion 20 is disposed in a central portion of the second housing 21 that forms the pump accommodating portion 20h. The second housing 21 includes a support portion 23 that supports an end portion 12b of the shaft 12 on the lower side. FIG. 10 is a perspective view of the pump portion 20 as viewed from the upper side, FIG. 11 is a perspective view of the second housing 21 accommodating the pump portion 20 as viewed from the lower side, and FIG. 12 is an exploded perspective view of the second housing 21 and the pump portion 20 as viewed from the other side in the axial direction (upper side).

[0051] As illustrated in FIG. 10, the second housing 21 includes a second opening 21a facing the +Z direction. A flange 21m extending outward in the radial direction is provided at an edge portion (outer circumferential portion) of the second opening 21a. A second surface 21n facing the +Z direction is formed on the flange 21m. The second surface 21n is a flat surface without a step. Further, a plurality of bolt holes 21p are formed in the flange 21m. The bolt holes 21p are formed at a predetermined interval in the circumferential direction of the flange 21m. In the present example embodiment, six bolt holes 21p are formed.

[0052] Then, as illustrated in FIG. 2, the flange 21m of the second housing 21 and the flange 11m of the first housing 11 are fastened by bolts 24 with the fixing portion 16e of the partition wall member 16 interposed therebetween. Further, O-rings 11j and 11j are located above and below the fixing portion 16e of the partition wall member 16, respectively. As illustrated in FIG. 13, the fastening of the flange 21m of the second housing 21 and the flange 11m of the first housing 11 brings the second surface 21n of the flange 21m and the first surface 11n of the flange 11m into surface contact with each other with the fixing portion 16e of the partition wall member 16 interposed therebetween.

[0053] The fixing portion 16e of the partition wall member 16 (lower side of the partition wall member 16) can be fixed to the housing H by sandwiching the fixing portion 16e of the partition wall member 16 between the flange 11m of the first housing 11 and the flange 21m of the second housing 21 and fixing the flange 21m to the flange 11m. That is, as described above, the upper side (first partition wall 16a) of the partition wall member 16 is fixed to the shaft 12, and the lower side (fixing portion 16e) of the partition wall member 16 is fixed to the housing H. With the upper side of the partition wall member 16 fixed to the shaft 12 and the lower side of the partition wall member 16 fixed to the housing H, the rigidity and shape stability of the partition wall member 16 are improved. The improvement in the rigidity and shape stability facilitates thinning of the partition wall member 16. Further, the O-rings 11j and 11j are respectively located above and below the fixing portion 16e of the partition wall member 16, making it possible to seal the fixing portion 16e of the partition wall member 16 (lower side of the partition wall member 16).

[0054] Furthermore, as illustrated in FIG. 2 and FIG. 11, the second housing 21 includes a suction port 25 connected to the pump accommodating portion 20h and an ejection port 26 located in an outer circumferential portion of the pump accommodating portion 20h. The suction port 25 is composed of a tube body 25a located coaxially with the center axial line J. The suction port 25 is located on one end portion (lower end) side of the shaft 12 in the axial direction. The suction port 25 is connected to a fluid supply path (not illustrated), and fluid from the fluid supply path flows into a central portion of the pump accommodating portion 20h. A diameter of the suction port 25 is the same as that of the ejection port 26. The suction port 25 is provided with the support portion 23 described below.

[0055] The ejection port 26 is formed of a tube body 26a located parallel to the center axial line J. The tube body 26a (ejection port 26) is located outward of the flange 21m of the second housing 21. As illustrated in FIG. 2 and FIG. 13, the lower side of the tube body 26a is open (open in the-Z direction). The upper side of the tube body 26a is closed. A communication port 26b is formed in a side surface of the tube body 26b. The communication port 26b is connected to an outlet side of an ejection flow path 21j in the pump accommodating portion 20h. A lower end (ejection port 26) of the tube body 26a is connected to a flow path (not illustrated), and ejects the fluid in the pump accommodating portion 20h into the flow path.

[0056] As illustrated in FIG. 11, the ejection flow path 21j is formed in the circumferential direction along an outer circumferential portion of the second housing 21. The ejection flow path 21j is formed as part of the second housing 21. The ejection flow path 21j forms an inner front surface of the pump housing 20h (FIG. 10). As illustrated in FIG. 2, a cross section of the ejection flow path 21j (cross section perpendicular to a travel direction of the fluid) is semicircular. The ejection flow path 21j having a semicircular cross section forms a curved portion reaching an outermost periphery of the second housing 21. The ejection flow path 21j collects fluid fed from the pump portion 20 to the outer side in the radial direction, causing the fluid to flow toward the ejection port 26 side.

[0057] As illustrated in FIG. 12 and FIG. 13, a bottom portion 21c of the second housing 21 has a flat shape. An outer circumferential portion of the bottom portion 21c is connected to an inner circumferential side of the ejection flow path 21j. A projecting portion 21d having a tubular shape and connected to the tube body 25a of the suction port 25 is provided in a central portion of the bottom portion 21d. The projecting portion 21d extends downward from the central portion of the bottom portion 21c. An inner groove 21e is formed in the circumferential direction on an inner side of the projecting portion 21d. An inner diameter of the inner groove 21e is larger than an inner diameter of the tube body 25a, forming a stepped portion as a connecting portion between the inner groove 21e and the tube body 25a. Part of the pump portion 20 is located in the inner groove 21e. Further, the second housing 21 includes a curved portion from the suction port 25 to the flange 11m at an outermost diameter.

[0058] As illustrated in FIG. 10 and FIG. 13, a stepped portion 21f is formed on the inner periphery of an upper portion of the second housing 21 in the circumferential direction of the second housing 21. The stepped portion 21f includes a first wall surface 21g facing the inner side in the radial direction and a second wall surface 21h facing the other side in the axial direction. The first wall surface 21g constitutes an inner circumferential surface of the flange 21m of the second housing 21. The first wall surface 21g is continuous with the second surface 21n of the flange 21m. The second wall surface 21h is located above the ejection flow path 21j.

[0059] The third partition wall 16c and the fourth partition wall 16d of the partition wall member 16 are located on the stepped portion 21f. More specifically, as illustrated in FIG. 13, the third partition wall 16c of the partition wall member 16 is located on the second wall surface 21h, and the fourth partition wall 16d of the partition wall member 16 is located on the first wall surface 21g. A lower portion (third partition wall 16c and fourth partition wall 16d) of the partition wall member 16 is located on the stepped portion 21f, ensuring the shape stability of the lower portion of the partition wall member 16.

[0060] As illustrated in FIG. 2, the pump portion 20 is connected to the lower side of the rotor 13. In the present example embodiment, the pump portion 20 is an impeller. The impeller constituting the pump portion 20 is made of a metal in the present example embodiment. Note that the impeller may be made of a resin. As illustrated in FIG. 12, the pump portion 20 includes the impeller main body 20a, a shroud 20b, and a plurality of blades 20c. The impeller main body 20a has a disk shape about the center axial line J. A first through-hole 20d is formed in a central portion of the impeller main body 20a. A fitting body 20e having a tubular shape and extending upward is formed at an edge portion of the first through-hole 20d.

[0061] Then, as illustrated in FIG. 13, the pump portion 20 is connected to the rotor support shaft 13d of the rotor 13, causing the pump portion 20 to rotate with the rotation of the rotor 13. Specifically, one end portion (lower end) 13e, in the axial direction, of the rotor support shaft 13d having a sleeve shape is fitted to the inner side of the fitting body 20e of the impeller main body 20a by press-fitting. Furthermore, the fitting portion is welded. The impeller main body 20a and the rotor support shaft 13d are coupled by press-fitting and welding. An inner diameter of the fitting body 20e is substantially the same as or slightly smaller than the inner diameter of the tube body 25a of the suction port 25.

[0062] As illustrated in FIG. 12, the shroud 20b is a member separate from the impeller main body 20a. The shroud 20b is disposed below the impeller main body 20a with an interval therebetween. The shroud 20b has a disk shape that is substantially the same shape as that of impeller main body 20a. A second through-hole 20f is formed at a center of the shroud 20b. A guide body 20g having a tubular shape and extending downward is provided at an edge portion of the second through-hole 20f. Reference sign 20j denotes a connecting portion between the second through-hole 20f and the guide body 20g. The connecting portion 20j is arc-shaped to smoothen the flow of the fluid. As illustrated in FIG. 13, an inner diameter of the guide body 20g is the same as the inner diameter of the tube body 25a of the suction port 25.

[0063] As illustrated in FIG. 13, the guide body 20g is located so as to fit to the inner groove 21e having an annular shape and formed on the inner side of the projecting portion 21d of the suction port 25. However, the guide body 20g rotates together with the shroud 20b, and thus does not come into contact with the inner groove 21e. That is, there is a gap in the radial direction between the guide body 20g and the inner groove 21e. Further, a lower surface of the shroud 20b faces the bottom portion 21c of the second housing 21, but does not come into contact with the bottom portion 21c. That is, there is a gap in the axial direction (Z direction) between the lower surface of the shroud side 20b and the bottom portion 21c.

[0064] As illustrated in FIG. 12, the impeller main body 20a is spaced apart from the shroud 20b in the axial direction, and the blades 20c are located between the impeller main body 20a and the shroud 20b. The blade 20c is formed by bending a strip-shaped metal piece in one direction. In the present example embodiment, seven blades 20c are disposed at regular intervals in the circumferential direction, with orientations of curvature of the blades 20c being made the same. Each blade 20c extends from the second through-hole 20f of the shroud 20b to an outer circumferential edge of the shroud 20b. A bottom portion of each blade 20c is fixed to the shroud 20b by welding. An upper portion of each blade 20c is also fixed to the impeller main body 20a by welding. The impeller main body 20a and the shroud 20b are connected to each other via the plurality of blades 20c.

[0065] When the pump portion (impeller) 20 rotates with the rotation of the rotor 13, the fluid in the pump accommodating portion 20h is pushed out to the outer circumferential side of the pump portion 20 by a centrifugal force of the pump portion 20, and ejected from the ejection port 26 through the ejection flow path 21j (OUT in FIG. 2). When the fluid is ejected from the ejection port 26, a pressure in the pump accommodating portion 20h becomes negative, suctioning the fluid into the pump accommodating portion 20h from the suction port 25 (IN in FIG. 2). The fluid is continuously fed out from the pump portion 20 by a similar action. The inside of the pump accommodating portion 20h and the space accommodating the rotor 13 communicate with each other. Therefore, part of the fluid in the pump accommodating portion 20h flows into the rotor 13 side with the rotation of the pump portion 20. However, the rotor 13 and the stator 15 are separated and sealed by the partition wall member 16, and thus the fluid in the rotor 13 does not flow (leak) to the stator 15 side. Further, the pressure inside the pump accommodating portion 20h constantly fluctuates by the flow (ejection and suction) of the fluid. The pressure fluctuation also acts on the partition wall member 16 facing the inside of the pump accommodating portion 20h.

[0066] As illustrated in FIG. 2 and FIG. 13, the support portion 23 is disposed at an axial central portion of the pump portion 20. The support portion 23 supports the end portion 12b of the shaft 12 on the lower side (one side in the axial direction). The support portion 23 includes a shaft fitting portion 23a and a plurality of support legs 23b. As illustrated in FIG. 13 and FIG. 14, the shaft fitting portion 23a is located on the inner side of the fitting body 20e of the impeller main body 20a. A first recess portion 23c recessed toward the one side (lower side) in the axial direction is formed in an end surface of the shaft fitting portion 23c on the other side (upper side) in the axial direction. The end portion 12b of the shaft 12 is fitted to the first recess portion 23c. FIG. 14 is a partially enlarged view illustrating section A of FIG. 13.

[0067] The first recess portion 23c has a shape matching an outer shape of the end portion 12b of the shaft 12. As can be seen from FIG. 12, the outer shape of the end portion 12b of the shaft 12 is composed of a portion having a circular cross section and a notch (flat portion) 12d. Therefore, the shape of the first recess portion 23c is a shape matching those of the circular cross section and the notch 12d. If the end portion 12b of the shaft 12 has a polygonal shape, the first recess portion 23c also has a shape matching the polygonal shape. If the end portion 12b of the shaft 12 has a projection, a keyway, or the like, the first recess portion 23c also has a shape matching the projection or the like. Further, the end portion 12b of the shaft 12 may be machined so as to be snap-fitted to the first recess portion 23c. In this case, the first recess portion 23c and the shaft 12 are coupled to each other by simply fitting the end portion 12b of the shaft 12 into the first recess portion 23c. Furthermore, the first recess portion 23c may be formed with a stepped portion by cutting a groove having a wide width, for example, instead of simply cutting a hole.

[0068] As illustrated in FIG. 12 and FIG. 14, a washer 14a is provided between the shaft fitting portion 23a and the bearing 14. The washer 14a prevents the bearing 14 rotating together with the rotor 13 and the fixed fitting portion 23a from being worn by direct contact. Furthermore, as illustrated, a projection 14b having a linear shape is formed on part of an inner periphery of the washer 14a. The projection 14b is located so as to fit into the notch 12d of the end portion 12b of the shaft 12 when the end portion 12b of the shaft 12 is passed through the washer 14a. The projection 14b of the washer 14a is located at the notch 12d, causing the notch 12d to also function as a rotation stopper of the washer 14a (preventing co-rotation of the washer 14a).

[0069] As illustrated in FIG. 14, a second recess portion 12c extending in the axial direction is formed in the end portion 12b of the shaft 12. In the present example embodiment, the second recess portion 12c is a screw hole. A fixing portion 22 for fixing the shaft fitting portion 23a to the end portion 12b of the shaft 12 is screwed into the screw hole 12c. The fixing portion 22 is a screw or a bolt in the present example embodiment. A through-hole 23e connected to the first recess portion 23c is formed in a central portion of the shaft fitting portion 23a. The through-hole 23e is located below the first recess portion 23c. The fixing portion (screw) 22 is screwed into the through-hole 23e from the one side (lower side) in the axial direction toward the other side (upper side) in the axial direction. The screw 22 includes a screw head portion 22b at an end portion (lower end) on the one side in the axial direction. The screw head part 22b includes a screw end surface 22a facing the other side (upper side) in the axial direction.

[0070] As illustrated in FIG. 14, when the screw 22 is screwed into the screw hole 12c of the end portion 12b of the shaft 12 from the lower side of the through-hole 23e, the screw head portion 22b comes into contact with a first end surface 23g of the shaft fitting portion 23a. The first end surface 23g faces the one side (lower side) in the axial direction so as to face the screw end surface 22a of the screw head portion 22b. Further, a space S3 is formed in the axial direction between a second end surface 23h of the first recess portion 23c of the shaft fitting portion 23a and an end surface 12e of the end portion 12b of the shaft 12. The second end surface 23h faces the other side (upper side) in the axial direction so as to face the end surface 12e of the end portion 12b of the shaft 12.

[0071] A hole 22e (hexagonal hole, star-shaped hole, or the like) into which a tool for turning (screwing) the screw 22 is fitted is formed in the screw head portion 22b of the screw 22. A tool such as hexagonal wrench or a star wrench can be fitted into the hole 22e. When the screw 22 is screwed into the screw hole 12c of the end portion 12b of the shaft 12 by using a tool such as a hexagonal wrench to fix the support portion 23 to the end portion 12b of the shaft 12, the end portion 12b of the shaft 12 is pulled toward the support portion 23 side (tensile force in the-Z direction acts on the end portion 12b of the shaft 12). That is, when the screw 22 is fastened, a force for bringing the end portion 12b of the shaft 12 and the support portion 23 close to each other is generated in the axial direction. As illustrated in FIG. 13, the suction port 25 is located on an extending line of the screw 22 on the one side in the axial direction, making it possible to screw the screw 22 into the end portion 12b of the shaft 12 by utilizing the suction port 25.

[0072] As illustrated in FIG. 13, the shaft fitting portion 23a is supported by the plurality of support legs 23b on the lower side of the shaft fitting portion 23a. In the present example embodiment, three support legs 23b support the shaft fitting portion 23a. As illustrated in FIG. 13, the support legs 23b extend from an inner wall surface of the tube body 25a of the suction port 25 toward the other side in the axial direction. More specifically, the support legs 23b extend obliquely upward from the inner wall surface of the tube body 25a of the suction port 25 by a predetermined length, and then extend parallel to the center axial line J. Upper ends of the support legs 23b pass through the first through-hole 20d and the second through-hole 20f of the pump portion 20, and are connected to the first end surface 23g of the shaft fitting portion 23a. In the present example embodiment, three support legs 23b are disposed at equal intervals (120°) in the circumferential direction of the tube body 25a about the center axial line J.

[0073] As illustrated in FIG. 13, the end portion 12b of the shaft 12 is located upward (on the other side in the axial direction) of the third partition wall 16c of the partition wall member 16. That is, the end portion 12b of the shaft 12 does not reach the pump portion 20 side. Therefore, the shaft fitting portion 23a supporting the end portion 12b of the shaft 12 is in a position upward (on the other side in the axial direction) of the third partition wall 16c of the partition wall member 16, that is, protruding toward the motor accommodating portion 11h side of the first housing 11.

[0074] In the present example embodiment, as illustrated in FIG. 7, the second stepped portion 12a of the shaft 12 is placed on the shaft fixing portion 11c of the upper portion 11b of the first housing 11. Therefore, as illustrated in FIG. 13, a structure is formed in which the end portion 12b of the shaft 12 is fixed to the support portion 23 by a fixing portion such as the screw 22. However, in the case of a structure in which the shaft 12 rotates together with the rotor 13, a shaft receiving member may be newly attached to the support portion 23 instead of the screw 22. Further, the impeller constituting the pump portion 20 may be a trochoid pump, a gear pump, or a vane pump. Further, in the present example embodiment, the shaft fitting portion 23a of the support portion 23 is located on the other side (upper side) of the pump portion 20 in the axial direction, but may be located on the one side (lower side) of the pump portion 20 in the axial direction by extending the shaft 12.Control Unit 30

[0075] The control unit 30 supplies a drive current to the motor part 10. As illustrated in FIG. 2, the control unit 30 includes the third housing 31 including a substrate accommodating chamber 30a, a substrate 32 accommodated in the substrate accommodating chamber 30a, electronic components 33, and the like. The third housing 31 is formed of a metal such as aluminum or steel having excellent thermal conductivity. A cooling fin 31a, a cable-connecting part 31b, and the like are provided on an upper surface of the third housing 31. A sleeve 31c extending toward the one side in the axial direction is formed on the lower side of the third housing 31. The sleeve 31c is fitted so as to cover the upper portion 11b of the first housing 11 from the outside.

[0076] The electronic components 33 are mounted on the substrate 32. The electronic components 33 include, for example, an integrated circuit (IC), a transistor, and a capacitor. The electronic components 33 constitute a control circuit for controlling the electric pump 100. The substrate 32 is attached to the upper side of the upper portion 11b of the first housing 11. Power is supplied from the substrate 32 to the coils 15c of the stator 15 via the connection terminals 19d of the bus bar assembly 19, causing the stator 15 to operate.Actions and Effects

[0077] As illustrated in FIG. 2, FIG. 10, and FIG. 12, in the electric pump 100 of the present example embodiment, the end portion 12b of the shaft 12 on the lower side is supported by the support portion 23 of the pump accommodating portion 20h. The cantilevered support state of the shaft 12 is released by the end portion 12b of the shaft 12 on the lower side being supported by the support portion 23 of the pump accommodating portion 20h. When the cantilevered support state of the shaft 12 is released, even if the centrifugal force of the rotor 13 is applied to the shaft 12, it is possible to suppress deflection or wobbling of the shaft 12.

[0078] In the present example embodiment, as illustrated in FIG. 13, the support portion 23 that supports the shaft 12 includes the shaft fitting portion 23a, and this shaft fitting portion 23a is fitted to the end portion 12b of the shaft 12. By fitting the end portion 12b of the shaft 12 to the shaft fitting portion 23a, it is possible to provide accurate support without the end portion 12b of the shaft 12 being displaced in the radial direction. Further, the end portion 12b of the shaft 12 can be supported by simply being fitted into the shaft fitting portion 23a, making a pump assembly task easier.

[0079] In the present example embodiment, the shaft fitting portion 23a includes the first recess portion 23c recessed toward the upper side, and the shape of the first recess portion 23c coincides with the outer shape of the end portion 12b of the shaft 12. With the shape of the first recess portion 23c coinciding with the outer shape of the end portion 12b of the shaft 12, the outer shape of the end portion 12b of the shaft 12 and the shape of the first recess portion 23c can be not only a circular cross-sectional shape as illustrated in FIG. 12, but also the notch 12d shape, a polygonal shape, or the like. If the shapes of the end portion 12b of the shaft 12 and the first recess portion 23c are formed in the notch 12d shape, a polygonal shape, or the like, it is possible to prevent the shaft 12 from rotating relative to the shaft fitting portion 23a in a state in which the end portion 12b of the shaft 12 is fitted to the first recess portion 23c.

[0080] In the present example embodiment, as illustrated in FIG. 14, the fixing portion 22 such as a screw is fixed to the second recess portion 12c of the end portion 12b of the shaft 12 through the through-hole 23e of the support portion 23. The fixing portion 22 is fixed to the shaft 12 from the support portion 23 side, making it possible not only to support the end portion 12b of the shaft 12 but also prevent the end portion 12b of the shaft 12 from being displaced or detached.

[0081] In the present example embodiment, as illustrated in FIG. 14, the screw 22 as a fixing portion is passed through the through-hole 23e of the support portion 23 and screwed into the screw hole 12c of the end portion 12b of the shaft 12, making it possible to suitably fix the end portion 12b of the shaft 12 to the support portion 23 side. Further, in a state in which the screw end surface 22a of the screw 22 is in contact with the first end surface 23g of the support portion 23, the space s3 exists between the end surface 12d of the shaft 12 and the second end surface 23h of the support portion 23. Therefore, when the screw 22 is further fastened to the screw hole 12c from this state, the end portion 12b of the shaft 12 is pulled toward the support portion 23 side by an axial force of the screw 22, generating tension in the axial direction in the shaft 12. This tension improves the rigidity of the shaft 12 and thus, even when the centrifugal force of the rotor 13 is applied, it is possible to more suitably suppress deflection of the shaft 12.

[0082] In the present example embodiment, as illustrated in FIG. 3, the first housing 11 includes the upper portion 11b located above the stator 15 or the rotor 13, and this upper portion 11b includes the shaft fixing portion 11c as illustrated in FIG. 2. The end portion 12b of the shaft 12 is fixed to the shaft fixing portion 11c, preventing the shaft 12 from coming off (falling off) from the upper portion 11b of the first housing 11, even when the shaft 12 is pulled toward the one side in the axial direction by the axial force of the screw.

[0083] In the present example embodiment, as illustrated in FIG. 7, the shaft fixing portion 11c includes the first stepped portion s1, and the end portion (upper end portion) of the shaft 12 includes the second stepped portion 12a facing the first stepped portion s1 in the axial direction. The shaft fixing portion 11c fixes the shaft 12 such that the second stepped portion 12a and the first stepped portion s1 face each other in the axial direction. With the second stepped portion 12a and the first stepped portion s1 fixed so as to face each other in the axial direction, when the screw 22 is screwed into the end portion 12b of the shaft 12 on the lower side, an axial force of the screw 22 is generated, and the shaft 12 receives the axial force and is pulled to the one side in the axial direction. Even if the shaft 12 receives the tension pulling the shaft 12 to the one side in the axial direction, the end portion 12a of the shaft 12 is caught by the upper portion 11b of the first housing 11 and does not come off (fall off) from the shaft fixing portion 11c. This makes it possible to further increase the tension of the shaft 12 by further increasing a fastening torque of the screw 22, thereby further improving the rigidity of the shaft 12.

[0084] The first stepped portion s1 and the second stepped portion 12a may be partially uneven in the radial direction. Further, the first stepped portion s1 may be formed not only at the upper edge of the shaft fixing hole h1, but also at an intermediate portion of the shaft fixing hole h1 (upper portion 11b) as in the case of insertion by resin-molding. However, if the first stepped portion s1 is formed at the upper edge of the shaft fixing hole h1, the machining is easier as compared with a case of formation at the intermediate portion of the shaft fixing hole 11b (upper portion 11b), making it possible to shorten a machining time. This makes it possible to reduce manufacturing costs.

[0085] In the present example embodiment, as illustrated in FIG. 2, the pump accommodating portion 20h includes the suction port 25 below the support portion 23. This makes it possible to directly view the inside of the pump accommodating portion 20h from this suction port 25. When a tool or the like is inserted from this suction port 25 while the support portion 23 in the pump accommodating portion 20h is visually observed, it is possible to easily perform attachment tasks or fastening tasks of fixing portions such as the screw 22 to the support portion 23.

[0086] In the present example embodiment, as illustrated in FIG. 4 and FIG. 10, the second housing 21 constituting the pump accommodating portion 20h includes the second surface 21n contacting the first surface 11n of the first housing 11 constituting the motor accommodating portion 11h. The first surface 11n and the second surface 21n are in surface-contact with each other, making it possible to receive, by the surface toward the motor accommodating portion 11h side, the stress received by the pump accommodating portion 20h by the axial force of the screw 22. This makes it possible to avoid stress concentration on the support portion 23. With the stress concentration on the support portion 23 avoided, the durability of the pump accommodating portion 20h against stress is improved, making it possible to suitably support the shaft 12 by the support portion 23. Furthermore, the stress concentration on the support portion 23 can be avoided, making it possible to further improve the rigidity of the shaft 12 by sufficiently increasing the fastening torque of the screw 22.

[0087] In the present example embodiment, as illustrated in FIG. 11 and FIG. 13, the pump accommodating portion 20h includes the curved portion 21j from the support portion 23 to the outermost diameter of the pump accommodating portion 20h. When the screw 22 is fastened to generate axial force, the pump accommodating portion 20h is also subjected to stress due to the axial force via the support portion 23. Even when stress is applied to the pump accommodating portion 20h, because the curved portion 21j exists from the support portion 23 that receives the axial force to the second surface 21n joined with the pump accommodating portion 20h, it is possible to avoid the concentration of stress in the pump accommodating portion 20h. Thus, because the concentration of stress in the pump accommodating portion 20h can be avoided, the pump accommodating portion 20h improves in durability and reliability. Note that the curved portion 21j may be a curved portion with not only rounded external corners but also rounded internal corners, extending to the outermost diameter of the pump accommodating portion 20h.

[0088] In the present example embodiment, as illustrated in FIG. 14, the end surface 12e of the end portion 12b of the shaft 12 is located above the pump portion 20, and the support portion 23 is located on the motor accommodating portion 11h. With the support portion 23 supporting the shaft 12 positioned on the motor accommodating portion 11h side, a length of the shaft 12 can be shortened. With the length of the shaft 12 shortened, it is possible to reduce a deflection amount of the shaft 12.

[0089] In the present example embodiment, the shaft 12 adopts a structure of being fixed to the upper portion 11b of the first housing 11 and not rotating. However, an electric motor having a structure in which the shaft 12 rotates also exists. In the case of the structure in which the shaft 12 rotates, if a shaft receiving member is provided on the shaft fitting portion 23a, even if the shaft 12 rotates, it is possible to prevent the shaft 12 from deflecting while rotatably supporting the end portion of the shaft 12.

[0090] As illustrated in FIGS. 2 and 13, in the electric pump 100 of the present example embodiment, the second housing 21 positioned on the pump assembly 20 side includes the shaft fitting portion 23a fitted to the end portion 12b on one side in the axial direction (lower side) of the shaft 12 on the motor assembly 10 side. The second housing 21 is provided with the shaft fitting portion 23a, whereby the shaft fitting portion 23a fits the end portion 12b on the lower side of the shaft 12 when the second housing 21 is assembled to the first housing 11. The end portion 12b on the lower side of the shaft 12 is fitted to the shaft fitting portion 23a, whereby the shaft fitting portion 23a no longer radially shifts with respect to the shaft 12. Since the shaft fitting portion 23a no longer radially shifts, the position of the second housing 21 including the shaft fitting portion 23a also no longer radially shifts with respect to the first housing 11, the rotor 13, and the like. Since the shaft fitting portion 23a and the second housing 21 no longer radially shift with respect to the first housing, the rotor 13, and the like, it is possible to prevent the second housing from interfering with the pump assembly and sealing performance from deteriorating.

[0091] In the present example embodiment, the end portion 12b on the lower side of the shaft 12 is fitted to the shaft fitting portion 23a of the second housing, whereby the radial position of the second housing is determined, and the radial shift of the second housing can be prevented. Therefore, the first opening portion 11k of the first housing 11 illustrated in FIG. 4 and the second opening portion 21a of the second housing 21 illustrated in FIG. 10 do not need to have a fitting structure. Since the first opening portion 11k and the second opening portion 21a do not need to have a fitting structure, it is possible to provide a groove 11r (FIG. 4) for assembling a seal portion such as the O-ring 11j while suppressing the radial size of each of the opening portions 11k and 21a. Since the surface 21n (FIG. 10) of the second housing 21 to be assembled to the first housing 11 side can be configured as a flat surface, machining is easy and the cost related to machining can be suppressed. Since the number of times of contact of the tool at the time of machining is also reduced, the accuracy of a machined surface is easily improved, and the assembly accuracy at the time of assembly to the first housing 11 side is also improved.

[0092] In the present example embodiment, as illustrated in FIG. 14, the screw 22, which is a fixing portion, passes through the through-hole 23e of the shaft fitting portion 23a and is screwed into the screw hole 12c of the end portion 12b of the shaft 12. By screwing the screw 22 into the screw hole 12c of the shaft 12, it is possible to suitably fix the end portion 12b of the shaft 12 to the shaft fitting portion 23a. In a state where the screw end surface 22a of the screw 22 is in contact with the first end surface 23g of the shaft fitting portion 23a, there is the gap s3 between an end surface 23d of the shaft 12 and the second end surface 23h of the shaft fitting portion 23a. Therefore, when the screw 22 is further tightened, the end portion 12b of the shaft 12 is pulled on the shaft fitting portion 23a side by the axial force of the screw 22, and tension pulling the shaft 12 and the shaft fitting portion 23a against each other is generated. The surface pressure between the second surface of the second opening portion 21a of the second housing 21 and the first surface 11n of the first opening portion 11k of the first housing 11 is increased by the tension pulling the shaft 12 and the shaft fitting portion 23a against each other. Since the second housing 21 is more strongly fixed to the first housing 11 by increasing the surface pressure, it is possible to more suitably prevent shift of the second housing 21 in any direction with respect to the first housing 11.

[0093] In the present example embodiment, as illustrated in FIG. 3, the first housing 11 includes the upper portion 11b positioned on an upper side relative to the stator 15 or the rotor 13, and the upper portion 11b includes the shaft fixing portion 11c as illustrated in FIG. 2. By fixing the end portion 12b of the shaft 12 to the shaft fixing portion 11c, the shaft 12 no longer comes off (falls off) from the upper portion 11b of the first housing 11 even if the shaft 12 is pulled by the axial force of the screw. The shaft 12 no longer comes off, whereby the second housing 21 can be fixed to the first housing 11 with stronger tension, and therefore the second housing 21 can be more suitably prevented from shifting radially.

[0094] In the example embodiment, as illustrated in FIG. 7, the shaft fixing portion 11c includes the first step portion s1, and an upper end portion of the shaft 12 includes the second step portion 12a facing the first step portion s1 in the axial direction. Therefore, the second step portion 12a of the shaft 12 is fixed so as to axially face the first step portion s1 of the shaft fixing portion 11c. Since the second step portion 12a of the shaft 12 is fixed, even if the shaft 12 is pulled by the axial force of the screw 22, the end portion 12b of the shaft 12 is caught by the upper portion 11b of the first housing 11 and no longer comes off (falls off) from the shaft fixing portion 11c to one side in the axial direction. Therefore, tension of the shaft 12 can be further increased, and the second housing 21 is more strongly fixed to the first housing 11. By strongly fixing the second housing 21 to the first housing 11, it is possible to more suitably prevent the second housing 21 from shifting radially.

[0095] In the present example embodiment, as illustrated in FIG. 2, the pump housing portion 20h includes the suction port 25 on the lower side relative to the shaft fitting portion 23a. Therefore, the support portion 23 in the pump housing portion 20h can be directly viewed from the suction port 25. By inserting a tool or the like from the suction port 25 while viewing the inside of the pump housing portion 20h, it is possible to easily perform attachment work and tightening work of a fixing portion such as the screw 22 with respect to the shaft fitting portion 23a. Attachment work and tightening work are simplified, whereby it is possible to perform tightening work of the screw 22 by a strong axial force without requiring a high level of skill. The tightening work of the screw 22 by the strong axial force becomes easy, which enables the second housing 21 to be more strongly fixed to the first housing 11, and therefore the second housing 21 can be more suitably prevented from shifting radially.

[0096] In the present example embodiment, as illustrated in FIG. 13, the shaft fitting portion 23a is positioned on the other side in the axial direction (upper side) relative to an impeller body portion 23a constituting the pump assembly 20. Therefore, the shaft fitting portion 23a does not hinder the fluid flow in the pump assembly 20, and does not adversely affect the pump performance. That is, since the shaft fitting portion 23a does not exist in a fluid flow path of the pump assembly 20, the shaft fitting portion 23a no longer serves as resistance to the fluid flow. Conversely, the shaft fitting portion 23a may be positioned on one side in the axial direction (lower side) relative to the pump assembly 20. The shaft fitting portion 23a is shifted on a lower side relative to the pump assembly 20 and arranged, whereby the shaft fitting portion 23a is no longer positioned in the pump assembly 20, and therefore it is possible to suppress an adverse effect of the fluid flow in the pump assembly 20.

[0097] In the present example embodiment, as illustrated in FIG. 13, the shaft fitting portion 23a is positioned on the other side in the axial direction (upper side) relative to the impeller body portion 23a constituting the pump assembly 20. Therefore, the shaft fitting portion 23a does not hinder the fluid flow in the pump assembly 20, and does not adversely affect the pump performance. As illustrated in FIG. 13, the fluid passes through the second through-hole 20f of the shroud 20b of the pump assembly 20 from the suction port 25, and sequentially flows from the radially outside of the pump assembly 20 to the discharge flow path 21j by the vane 20c. Therefore, the shaft fitting portion 23a does not hinder the fluid flow as compared with a case of being arranged at a center portion of the vane 20c. The support leg 23b supporting the shaft fitting portion 23a has a shape extending axially from the inner wall surface of the tube body 25a of the suction port 25. Furthermore, the support legs 23b are arranged at large intervals in the circumferential direction. Therefore, the support legs 23b also do not interfere with the fluid flow.

[0098] In the present example embodiment, as illustrated in FIG. 4, the first opening portion 11k of the first housing 11 includes the first surface 11n having a planar shape including the flange 11m. On the other hand, the opening portion 21a of the second housing 21 assembled to the second opening portion 11k of the first housing 11 includes the second surface 21n having a planar shape including the flange 21m. The first surface 11n and the second surface 21n are in contact with each other in a flat surface. Therefore, as illustrated in FIG. 3, the fixing portion 16e of the partition wall member 16 can be pressed over the entire surface, and excellent sealing performance can be exhibited. By making the first surface 11n and the second surface 21n planar, it is not necessary to provide the first opening portion 11k and the second opening portion 21a with a complicated fitting structure (spigot). The fixing portion 16e of the partition wall member 16 may be flat similarly to the first surface 11n and the second surface 21n, and does not need a special shape or special accuracy.

[0099] The example embodiments described above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing example embodiments, and all changes that fall within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. For example, the first partition wall 16a of the partition wall member 16 and the auxiliary member 17 may have polygonal shapes other than disk shapes. Further, the recessed portion 17b of the auxiliary member 17 and the protruding portion 11d of the upper portion 11b fitted thereto may also have polygonal shapes. Furthermore, the electric pump according to the present disclosure can have configurations such as the following.(1)

[0100] An electric pump including:

[0101] a shaft extending in an axial direction;

[0102] a rotor located outward of the shaft in a radial direction and configured to be rotatable;

[0103] a stator located outward of the rotor in the radial direction and surrounding the rotor;

[0104] a pump portion located on one side of the shaft in the axial direction; and

[0105] a housing including a pump accommodating portion configured to accommodate the pump portion; wherein

[0106] the pump accommodating portion includes a support portion to support an end portion of the shaft on the one side in the axial direction.(2)

[0107] The electric pump according to (1), wherein

[0108] the support portion includes a shaft fitting portion; and

[0109] the shaft fitting portion is fitted to the end portion of the shaft.(3)

[0110] The electric pump according to (2), wherein

[0111] the shaft fitting portion includes a first recess portion recessed toward the other side in the axial direction; and

[0112] a shape of the first recess portion coincides with an outer shape of the end portion of the shaft.(4)

[0113] The electric pump according to (3), wherein

[0114] the second recess portion is a screw hole extending in the axial direction;

[0115] the fixing portion is a screw screwed into the screw hole;

[0116] the support portion includes:

[0117] a first end surface opposing the one side in the axial direction; and

[0118] a second end surface opposing the other side in the axial direction;

[0119] the screw includes a screw end surface opposing the other side in the axial direction and contacting the first end surface; and

[0120] a gap is provided between a shaft end surface of the end surface on the one side in the axial direction and the second end surface.(5)

[0121] The electric pump according to (1), wherein

[0122] the housing includes an upper portion located on the other side of the stator or the rotor in the axial direction; and

[0123] the upper portion includes a shaft fixing portion configured to fix an end portion of the shaft on the other side in the axial direction.(6)

[0124] The electric pump according to (2), wherein

[0125] the shaft fixing portion includes a first stepped portion; and

[0126] an end portion of the shaft on the other side in the axial direction includes a second stepped portion opposing the first stepped portion in the axial direction.(7)

[0127] The electric pump according to (1), wherein

[0128] the pump accommodating portion includes a suction port on the one side of the support portion in the axial direction.(8)

[0129] The electric pump according to (4), wherein

[0130] the housing includes:

[0131] a motor accommodating portion to accommodate the stator; and

[0132] the pump accommodating portion connected to the motor accommodating portion; and

[0133] the pump accommodating portion includes a connection surface surface-contacting the motor accommodating portion side.(9)

[0134] The electric pump according to (1), wherein

[0135] an end surface of the end portion of the shaft is located on the other side of the pump portion in the axial direction; and

[0136] the support portion is located in the motor accommodating portion on the other side of the pump portion in the axial direction.(10)

[0137] The electric pump according to (2), wherein

[0138] the shaft fitting portion includes a bearing portion, and

[0139] the end portion is fitted to the bearing portion.(11)

[0140] An electric pump comprising:

[0141] a motor assembly including a shaft extending axially, a rotor positioned radially outside relative to the shaft and rotatable, and a stator surrounding the rotor;

[0142] a pump assembly positioned on one side in the axial direction of the shaft; and

[0143] a housing that covers the motor assembly and the pump assembly; wherein

[0144] the housing includes:

[0145] a first housing positioned on the motor portion side; and

[0146] a second housing positioned on the pump assembly side; and

[0147] the second housing includes a shaft fitting portion fitted to an end portion of the one side in the axial direction of the shaft.(12)

[0148] The electric pump according to (11), wherein

[0149] the first housing includes:

[0150] a first opening portion that opens on the one side in the axial direction; and

[0151] a stator housing portion that houses the stator;

[0152] the second housing includes:

[0153] a second opening portion that opens on the other side in the axial direction; and

[0154] a pump housing portion that houses the pump assembly; and

[0155] the second opening portion contacts the first opening portion on a surface opposing the other side in the axial direction of the second opening portion.(13)

[0156] The electric pump according to (12), wherein

[0157] the shaft fitting portion includes a first recess portion recessed on the one side in the axial direction; and

[0158] the first recess portion is fitted to an outer shape of the end portion.(14)

[0159] The electric pump according to (11), wherein

[0160] the shaft fitting portion includes a through-hole penetrating axially;

[0161] the end portion of the shaft includes a second recess portion recessed on the other side in the axial direction; and

[0162] the second recess portion is fixed by a fixing portion passing through the through-hole.(15)

[0163] The electric pump according to (14), wherein

[0164] the second recess portion is a screw hole extending axially;

[0165] the fixing portion is a screw threaded into the screw hole;

[0166] the shaft fitting portion includes a first end surface opposing the one side in the axial direction and a second end surface opposing the other side in the axial direction;

[0167] the screw includes a screw end surface opposing the other side in the axial direction and contacting the first end surface; and

[0168] a gap is present between a shaft end surface on the one side in the axial direction of the end portion and the second end surface(16)

[0169] The electric pump according to (11), wherein

[0170] the first housing includes an upper portion positioned on the other side in the axial direction relative to the stator or the rotor; and

[0171] the upper portion includes a shaft fixing portion that fixes an end portion on the other side in the axial direction of the shaft.(17)

[0172] The electric pump according to (12), wherein

[0173] the shaft fixing portion includes a first step portion; and

[0174] an end portion on the other side in the axial direction of the shaft includes a second step portion opposing the first step portion in the axial direction.(18)

[0175] The electric pump according to (11), wherein the shaft fitting portion is positioned on the other side in the axial direction or the one side in the axial direction relative to the pump assembly.(19)

[0176] The electric pump according to (11), wherein

[0177] the pump assembly includes a through-hole on a radially inner side;

[0178] the shaft fitting portion includes a support leg extending axially;

[0179] the support leg is positioned in the through-hole; and

[0180] the shaft fitting portion is positioned on the other side in the axial direction relative to the pump assembly.(20)

[0181] The electric pump according to (11), wherein

[0182] the first housing includes a first surface having a planar shape to be fixed to the second housing side;

[0183] the second housing includes a second surface having a planar shape to be fixed to the first housing side;

[0184] the second housing includes a seal portion that blocks inflow of fluid; and

[0185] the seal portion includes a fixing portion to be sandwiched between the first surface and the second surface.

[0186] Features of the above-described example embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

[0187] While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.

Claims

1. An electric pump comprising:a shaft extending in an axial direction;a rotor located outward of the shaft in a radial direction and configured to be rotatable;a stator located outward of the rotor in the radial direction and surrounding the rotor;a pump portion located on one side of the shaft in the axial direction; anda housing including a pump accommodating portion configured to accommodate the pump portion, whereinthe pump accommodating portion includes a support portion configured to support an end portion of the shaft on the one side in the axial direction.

2. The electric pump according to claim 1, whereinthe support portion includes a shaft fitting portion; andthe shaft fitting portion is fitted to the end portion of the shaft.

3. The electric pump according to claim 1, whereinthe support portion includes a through-hole penetrating in the axial direction;the end portion of the shaft includes a second recess portion recessed toward another side in the axial direction; andthe end portion is supported by the support portion by a fixing portion passing through the through-hole and fixed to the second recess portion.

4. The electric pump according to claim 3, whereinthe second recess portion is a screw hole extending in the axial direction;the fixing portion is a screw screwed into the screw hole;the support portion includes:a first end surface opposing the one side in the axial direction; anda second end surface opposing the other side in the axial direction;the screw includes a screw end surface opposing the other side in the axial direction and contacting the first end surface; anda gap is provided between a shaft end surface of the end surface on the one side in the axial direction and the second end surface.

5. The electric pump according to claim 1, whereinthe housing includes an upper portion located on the other side of the stator or the rotor in the axial direction; andthe upper portion includes a shaft fixing portion configured to fix an end portion of the shaft on the other side in the axial direction.

6. The electric pump according to claim 2, whereinthe shaft fixing portion includes a first stepped portion;and an end portion of the shaft on the other side in the axial direction includes a second stepped portion opposing the first stepped portion in the axial direction.

7. The electric pump according to claim 1, whereinthe pump accommodating portion includes a suction port on the one side of the support portion in the axial direction.

8. The electric pump according to claim 4, whereinthe housing includes:a motor accommodating portion to accommodate the stator; andthe pump accommodating portion connected to the motor accommodating portion; andthe pump accommodating portion includes a connection surface surface-contacting the motor accommodating portion side.

9. The electric pump according to claim 1, whereinan end surface of the end portion of the shaft is located on the other side of the pump portion in the axial direction; andthe support portion is located in the motor accommodating portion on the other side of the pump portion in the axial direction.

10. The electric pump according to claim 2, whereinthe shaft fitting portion includes a bearing portion, andthe end portion is fitted to the bearing portion.

11. An electric pump comprising:a motor assembly including a shaft extending axially, a rotor positioned radially outside relative to the shaft and rotatable, and a stator surrounding the rotor;a pump assembly positioned on one side in the axial direction of the shaft; anda housing that covers the motor assembly and the pump assembly; whereinthe housing includes:a first housing positioned on the motor portion side; anda second housing positioned on the pump assembly side; andthe second housing includes a shaft fitting portion fitted to an end portion of the one side in the axial direction of the shaft.

12. The electric pump according to claim 11, whereinthe first housing includes:a first opening portion that opens on the one side in the axial direction; anda stator housing portion that houses the stator; the second housing includes:a second opening portion that opens on the other side in the axial direction; anda pump housing portion that houses the pump assembly; andthe second opening portion contacts the first opening portion on a surface opposing the other side in the axial direction of the second opening portion.

13. The electric pump according to claim 12, whereinthe shaft fitting portion includes a first recess portion recessed on the one side in the axial direction; andthe first recess portion is fitted to an outer shape of the end portion.

14. The electric pump according to claim 11, whereinthe shaft fitting portion includes a through-hole penetrating axially;the end portion of the shaft includes a second recess portion recessed on the other side in the axial direction; andthe second recess portion is fixed by a fixing portion passing through the through-hole.

15. The electric pump according to claim 14, whereinthe second recess portion is a screw hole extending axially;the fixing portion is a screw threaded into the screw hole;the shaft fitting portion includes a first end surface opposing the one side in the axial direction and a second end surface opposing the other side in the axial direction;the screw includes a screw end surface opposing the other side in the axial direction and contacting the first end surface; anda gap is present between a shaft end surface on the one side in the axial direction of the end portion and the second end surface.

16. The electric pump according to claim 11, whereinthe first housing includes an upper portion positioned on the other side in the axial direction relative to the stator or the rotor; andthe upper portion includes a shaft fixing portion that fixes an end portion on the other side in the axial direction of the shaft.

17. The electric pump according to claim 12, whereinthe shaft fixing portion includes a first step portion; andan end portion on the other side in the axial direction of the shaft includes a second step portion opposing the first step portion in the axial direction.

18. The electric pump according to claim 11, wherein the shaft fitting portion is positioned on the other side in the axial direction or the one side in the axial direction relative to the pump assembly.

19. The electric pump according to claim 11, whereinthe pump assembly includes a through-hole on a radially inner side;the shaft fitting portion includes a support leg extending axially;the support leg is positioned in the through-hole; andthe shaft fitting portion is positioned on the other side in the axial direction relative to the pump assembly.

20. The electric pump according to claim 11, whereinthe first housing includes a first surface having a planar shape to be fixed to the second housing side;the second housing includes a second surface having a planar shape to be fixed to the first housing side;the second housing includes a seal portion that blocks inflow of fluid; andthe seal portion includes a fixing portion to be sandwiched between the first surface and the second surface.

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