Electric pump

Abstract

To reduce an axial dimension of an electric pump by eliminating the necessity of a rotor shaft of a rotor.SOLUTION: An electric pump uses an axial gap motor. A rotor includes an internal gear type outer rotor 430 and an external gear type inner rotor 450. The outer rotor 430 is accommodated in a rotor accommodation chamber while located coaxially with a stator and being not displaceable in the radial direction. The inner rotor 450 is accommodated in an internal gear space of the outer rotor 430 while being not displaceable in the radial direction and eccentric to a central axis of the outer rotor 430, and partially engages with the internal gear 434 of the outer rotor 430. A space Sp is formed between the internal gear 434 of the outer rotor 430 and the external gear 453 of the inner rotor 450. Integral rotation of the outer rotor 430, the inner rotor 450 and the space Sp constitutes a pump part in the rotor accommodation chamber.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present technology relates to an electric pump using an axial gap motor in which a stator and a rotor are arranged to face each other in the axial direction.

Background Art

[0002] The technology related to the above-described electric pump is described in Patent Document 1. As shown in FIGS. 11 and 12, the electric pump 100 described in Patent Document 1 includes a pump unit 110 and a motor unit 120. The pump unit 110 includes a substantially cylindrical pump chamber 113 formed at the center of a housing 112, a suction port 114 and a discharge port 115 communicating with the pump chamber 113. A disk-shaped rotor 122 is housed in the pump chamber 113 so as to be rotatable about a rotor shaft 123 in a state eccentric with respect to the pump chamber 113. The rotor 122 is a part constituting the rotor of the motor unit 120 (axial gap motor), and as shown in FIG. 11, is magnetized into two poles of an N pole and an S pole by half circles.

[0003] Vane grooves (not shown in the figure number) are formed at the outer peripheral portion of the rotor 122 at the 0° position and the 180° position, and vanes 124 are mounted in these vane grooves so as to be able to project radially outward by magnetic force and to be housed in the vane grooves under a pressing force in the radial direction. Further, a stator 126 of the motor unit 120 is attached coaxially with the rotor 122 below the housing 112 of the pump unit 110. That is, the stator 126 and the rotor 122 of the motor unit 120 are connected by a rotor shaft 123 so as to be coaxial. The stator 126 includes three coils 127 that generate a magnetic field, a back yoke 128, and an electric circuit unit 129 that energizes the coils 127 in a predetermined order. Thereby, the rotor 122 rotates about the rotor shaft 123 by the action of the magnetic flux generated by the coil 127 and the permanent magnet of the rotor 122, and the electric pump 100 is driven.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2007-51611 Summary of the Invention Problems to be Solved by the Invention

[0005] The rotor 122 that constitutes the pump section 110 of the electric pump 100 described above and the stator 126 of the motor section 120 are connected coaxially by the rotor shaft 123. For this reason, as shown in FIG. 12, the stator 126 of the motor section 120 requires a bearing section that supports the rotor shaft 123 in a rotatable state. For this reason, even if the axial dimension (vertical dimension) of the electric pump 100 is reduced by using an axial gap motor, there is a limit to the reduction of the dimension in the axial direction of the electric pump 100 due to the presence of the bearing section of the rotor shaft 126 on the stator 126 side.

[0006] This technology has been made to solve the above problems, and the problem to be solved by the present invention is to reduce the dimension in the axial direction of the electric pump by eliminating the bearing section of the rotor shaft on the stator side of the motor section. Means for Solving the Problems

[0007] The above problems are solved by each technology. The first technology is an electric pump using an axial gap motor in which a stator and a rotor are arranged to face each other in the axial direction. The rotor includes an inner gear type outer rotor and an outer gear type inner rotor. The outer rotor is coaxially arranged with the stator and is housed in a rotor housing chamber in a state where it cannot be displaced in the radial direction. The inner rotor is housed in the inner gear space of the outer rotor in a state where it cannot be displaced in the radial direction and is eccentric with respect to the central axis of the outer rotor, and is partially engaged with the inner gear of the outer rotor. A space is formed between the inner gear of the outer rotor and the outer gear of the inner rotor. By the integral rotation of the outer rotor, the inner rotor, and the space, a pump section is formed in the rotor housing chamber.

[0008] According to the above technology, the outer rotor constituting the rotor of the axial gap motor is coaxially arranged with the stator and is housed in a rotor housing chamber in a state where it cannot be displaced in the radial direction. That is, by housing the outer rotor in the rotor housing chamber, a rotor shaft for holding it coaxially with the stator as in the prior art becomes unnecessary. Further, the inner rotor constituting the rotor is housed in the inner gear space of the outer rotor in a state where it cannot be displaced radially outward and is eccentric with respect to the central axis of the outer rotor, and is partially engaged with the inner gear of the outer rotor. For this reason, the inner rotor cannot rotate relative to the outer rotor and rotates integrally with the outer rotor. In this way, since it is not necessary to provide a bearing portion for the rotor shaft on the stator side of the axial gap motor, it is possible to reduce the dimensions in the axial direction of the electric pump.

[0009] According to the second technology, the stator includes a stationary-side magnetic body composed of a stationary-side ring portion and a plurality of salient pole portions provided at equal intervals in the circumferential direction of the stationary-side ring portion, coils wound around respective salient pole portions of the stationary-side magnetic body, and a controller capable of switching energization in a predetermined order for the plurality of coils. The outer rotor of the rotor includes a ring portion provided coaxially with the stationary-side ring portion of the stator, and a plurality of salient pole portions provided at equal intervals in the circumferential direction of the ring portion and facing the salient pole portions of the stator, and a conductor covering the ring portion while surrounding the plurality of salient pole portions of the rotating-side magnetic body. The conductor is concentric with the rotating-side magnetic body and is formed to have a diameter larger by a certain dimension than the rotating-side magnetic body.

[0010] According to the above technology, the magnetic flux generated in the coils of the stator passes from the salient pole portions of the stationary-side magnetic body of the stator through the salient pole portions of the rotating-side magnetic body of the outer rotor. As a result, eddy currents flow in the conductor of the outer rotor so as to surround the salient pole portions of the rotating-side magnetic body. As a result, a force is generated in the direction of rotating the outer rotor between the magnetic flux and the eddy currents. Here, the conductor of the outer rotor is concentric with the rotating-side magnetic body and is formed to have a diameter larger by a certain dimension than the rotating-side magnetic body. Therefore, it becomes easier for eddy currents to flow so as to surround the salient pole portions of the rotating-side magnetic body.

[0011] According to the third technology, a cooling opening is formed in a wall portion closing an axial end of the internal gear space of the outer rotor to guide a part of the fluid in the space formed between the internal gear of the outer rotor and the external gear of the inner rotor to the position of the controller. Therefore, the controller can be cooled by the fluid guided from the cooling opening to the position of the controller.

[0012] According to the fourth technique, the housing that constitutes the rotor accommodation chamber is formed with a suction hole for supplying fluid into the rotor accommodation chamber and a discharge hole for discharging the fluid in the rotor accommodation chamber, and the opening areas of the suction hole and the discharge hole are set to be 10 times or more the opening area of the cooling opening formed in the outer rotor. Therefore, even if fluid is used for cooling the controller, it does not significantly affect the pump performance.

[0013] The electric pump according to the fifth technique is configured to be able to pump a fluid capable of cooling the drive motor of an electric vehicle.

Advantages of the Invention

[0014] According to the technique of the present application, since the bearing portion of the rotor shaft on the stator side becomes unnecessary, the dimension in the axial direction of the electric pump using the axial gap motor can be reduced.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0016] 〔Embodiment 1〕 Hereinafter, based on FIGS. 1 to 10, an electric pump according to Embodiment 1 of the present invention will be described. The electric pump 10 according to the present embodiment is a pump using an axial gap motor, and pumps lubricating oil and cooling oil for a drive motor of an electric vehicle. Here, the front, rear, left, right, and up and down directions in the drawing correspond to the front, rear, left, right, and up and down directions in the electric pump 10.

[0017] <Regarding the outline of the electric pump 10> As shown in FIG. 1, the electric pump 10 is a pump using an axial gap motor in which a stator 30 and a rotor 40 are arranged to face each other in the axial direction (in the up and down direction), and the rotor 40 constitutes a pump section (trochoid pump) within the housing 20. The electric pump 10 includes a cylindrical container-shaped housing 20, a stator 30 accommodated coaxially in the upper half of the housing 20, a rotor 40 accommodated coaxially in the lower half of the housing 20, and a controller 50 housed in the upper central opening of the stator 30.

[0018] <Regarding the housing 20> As shown in Fig. 1, the housing 20 is composed of a bottomed cylindrical housing main body 22 and a disc-shaped lid portion 24 that closes the upper opening of the housing main body 22. An annular shelf-shaped inner flange portion 22f is formed on the inner wall surface of the housing main body 22 at a position a certain dimension below the upper opening. The peripheral edge of the stator 30 of the axial gap motor is supported from below by the inner flange portion 22f of the housing main body 22. Further, a rotor 40 of the axial gap motor is housed below the inner flange portion 22f of the housing main body 22. That is, the lower side of the inner flange portion 22f of the housing main body 22 serves as a rotor housing chamber 22h that houses the rotor 40.

[0019] As shown in Fig. 4 and the like, the inner diameter dimension of the rotor housing chamber 22h of the housing main body 22 is set to a value that is larger by a clearance amount than the outer diameter dimension of the rotor 40 (outer rotor 430). That is, the outer rotor 430 of the rotor 40 is constrained from the outer side in the radial direction by the inner wall surface of the rotor housing chamber 22h of the housing main body 22. For this reason, the outer rotor 430 cannot be displaced in the radial direction even if there is no rotation center axis, and can rotate around the axis in a state coaxial with the stator 30.

[0020] As shown in FIG. 1, on the bottom plate 22b of the housing main body 22, a suction hole 25 for supplying oil and a discharge hole 26 for discharging oil are formed for a pump section (described later) constituted by a rotor housing chamber 22h and a rotor 40 (outer rotor 430, inner rotor 450). As shown in FIG. 4 and the like, the suction hole 25 is formed in an arc shape so as to surround the center on the front side of the central portion of the bottom plate 22b of the housing main body 22. Further, the discharge hole 26 is also formed in an arc shape so as to surround the center on the rear side of the central portion of the bottom plate 22b of the housing main body 22. Furthermore, a bearing hole (not shown in the figure) for supporting the lower end portion of the rotation center axis J of the inner rotor 450 is formed in the bottom plate 22b of the housing main body 22. As shown in FIG. 1, a connector 24c for supplying power to the controller 50 is provided at the rear portion of the lid portion 24 that closes the upper opening of the housing main body 22 so as to protrude upward. The housing 20 is formed of a resin such as plastic, for example.

[0021] <Regarding the stator 30> As shown in FIGS. 1 to 3, the stator 30 includes a stationary-side magnetic body 310 formed by laminating thin-plate electromagnetic steel sheets in the axial direction, and a plurality (six in the figure) of coils 35. The stationary-side magnetic body 310 is composed of a ring-shaped stationary-side ring portion 312 and a plurality (six in the figure) of salient pole portions 314 that protrude axially from the lower surface of the stationary-side ring portion 312 and are provided at equal intervals in the circumferential direction of the stationary-side ring portion 312. Then, as shown in FIG. 3, the above-described coils 35 are wound around each salient pole portion 314 of the stationary-side magnetic body 310. For the stator 30, the peripheral edge of the stationary-side ring portion 312 of the stationary-side magnetic body 310 is placed on the inner flange portion 22f of the housing main body 22 as shown in FIG. 1. Then, the salient pole portions 314 and the coils 35 of the stator 30 pass through the opening portion of the inner flange portion 22f of the housing main body 22 and protrude downward. Here, instead of forming the stationary-side magnetic body 310 by laminating electromagnetic steel sheets, it is also possible to form the stationary-side magnetic body 310 using a powder core.

[0022] <Regarding the controller 50> In the fixed-side ring portion 312 of the fixed-side magnetic body 310 of the stator 30, as shown in FIG. 1, the controller 50 is housed in a state of being covered with a disk-shaped cover member 54 in the circular opening 316. As shown in FIG. 3, the controller 50 is configured to be energized in a predetermined order with respect to the U-phase coil 35, the V-phase coil 35, and the W-phase coil 35 that are used in pairs. In the electric pump 10 according to the present embodiment, first, the coils 35 of the U-phase and V-phase in FIG. 3 are energized, then the coils 35 of the V-phase and W-phase are energized, and then the coils 35 of the W-phase and U-phase are energized. In this way, this energization order is repeatedly executed. As a result, the magnetic flux generated in the coil 35 rotates counterclockwise at a constant speed.

[0023] As shown in FIG. 1, the controller 50 is provided at the center of a disk-shaped electric circuit board 52, and the periphery of the electric circuit board 52 is covered on the fixed-side ring portion 312 of the fixed-side magnetic body 310 of the stator 30. And the conductive part of the electric circuit board 52 is connected to the connector 24c of the housing 20. Further, the cover member 54 that covers the controller 50 is formed of a material having high heat dissipation performance.

[0024] <Regarding the rotor 40> As shown in FIGS. 1 and 5, the rotor 40 is composed of an outer rotor 430 and an inner rotor 450. In FIGS. 5 and the like, the housing main body portion 22 is not shown. The outer rotor 430 includes a rotating-side magnetic body 437 formed by laminating thin plate-shaped electromagnetic steel sheets in the axial direction, and a rotor main body portion 431 that is a conductor made of an aluminum alloy and supports the rotating-side magnetic body 437 in a covered state. The rotor main body portion 431 of the outer rotor 430 is held in a state of being rotatable about the axis in the rotor housing chamber 22h of the housing main body portion 22 as described above (see FIGS. 1 and 4).

[0025] <Regarding the rotor main body portion 431 of the outer rotor 430> As shown in Fig. 1, on the outer peripheral edge of the rotor main body 431 of the outer rotor 430, a cylindrical vertical wall portion 432 is provided which is fitted between the inner flange portion 22f and the bottom plate 22b of the housing main body 22 to prohibit axial movement of the outer rotor 430. And, as shown in Fig. 4, a magnetic body support portion 433 in which the rotating-side magnetic body 437 is embedded is formed in a ring shape on the radially inner side of the cylindrical vertical wall portion 432 of the rotor main body 431.

[0026] Also, as shown in Fig. 5 and the like, an internal gear 434 is formed on the rotor main body 431 of the outer rotor 430 on the radially inner side of the magnetic body support portion 433. The internal gear 434 is formed with seven tooth grooves 434m at equal intervals in the circumferential direction, which can mesh with the external gear 453 of the inner rotor 450 (described later). That is, a cylindrical internal gear space S is formed by the internal gear 434 at the central portion of the rotor main body 431. As shown in Fig. 1 and Fig. 4, the rotor main body 431 is provided with a ceiling wall portion 435 that closes the upper opening of the internal gear space S formed by the internal gear 434. And, on the ceiling wall portion 435 of the rotor main body 431, a pair of cooling openings 435a, 435b are formed which communicate the internal gear space S of the rotor main body 431 and the housing inner space Su in the vicinity of the controller 50.

[0027] <Regarding the rotating-side magnetic body 437 of the outer rotor 430> As shown in Figs. 4 to 6 and Fig. 7, the rotating-side magnetic body 437 of the outer rotor 430 is composed of a ring portion 438 and a plurality of (eight in the figure) salient pole portions 439 that project axially from the upper surface of the ring portion 438 and are provided at equal intervals in the circumferential direction of the ring portion 438. And, the rotating-side magnetic body 437 is embedded in the magnetic body support portion 433 of the rotor main body 431, where the portion from the ring portion 438 to the vicinity of the tip of the salient pole portion 439 is a conductor (see Fig. 1 and the like).

[0028] Therefore, as shown in the schematic development view of FIG. 7, the magnetic flux φ (white arrow in FIG. 7) generated in the coil 35 of the stator 30 passes through a magnetic circuit composed of the stationary-side magnetic body 310 of the stator 30 and the rotating-side magnetic body 437 of the outer rotor 430. As a result, as shown in FIG. 8, an eddy current I flows around the salient pole portion 439 of the rotating-side magnetic body 437 of the outer rotor 430 (the rotor main body portion 431 which is a conductor). As a result, an electromagnetic force is generated between the magnetic flux φ and the eddy current I, and the outer rotor 430 rotates in the rotation direction of the magnetic flux φ generated in the coil 35 of the stator 30. Here, since the rotor main body portion 431 of the outer rotor 430 is formed to have a larger diameter than the ring portion 438 of the rotating-side magnetic body 437, the eddy current I easily flows around the salient pole portion 439 of the rotating-side magnetic body 437. Note that instead of configuring the rotating-side magnetic body 437 with an electromagnetic steel sheet, it is also possible to configure it using a powder core.

[0029] <Regarding the inner rotor 450> As shown in FIG. 5 and the like, the inner rotor 450 is an external gear type rotor that forms a trochoid pump together with the internal gear 434 of the outer rotor 430. The external gear 453 of the inner rotor 450 has six external teeth 453t at equal intervals in the circumferential direction. Also, the axial length dimension (height dimension in FIG. 1) of the external gear 453 is set to the same value as the axial length dimension of the internal gear 434 of the outer rotor 430. As a result, as shown in FIG. 1, the inner rotor 450 is sandwiched and constrained in the vertical direction (axial direction) by the ceiling wall portion 435 of the outer rotor 430 and the bottom plate 22b of the housing main body portion 22.

[0030] Three consecutive external teeth 453t (upper external teeth 453t in FIG. 5) of the external gear 453 of the inner rotor 450 mesh with three tooth grooves 434m of the internal gear 434 of the outer rotor 430. And the tip of the external tooth 453t located on the opposite side across the center from the central external tooth 453t among the three external teeth 453t of the external gear 453 (the lower external tooth 453t) abuts on the inner peripheral surface of the internal gear 434.

[0031] As a result, the inner rotor 450 is housed in the internal gear space S of the outer rotor 430 in an eccentric state with respect to the outer rotor 430 and is constrained from the radially outer side. That is, the center C1 of the inner rotor 450 is eccentric from the central axis C0 of the outer rotor 430. Further, the inner rotor 450 is held so as not to be relatively rotatable in the circumferential direction with respect to the outer rotor 430. That is, the inner rotor 450 rotates integrally with the outer rotor 430. The inner rotor 450 is rotatably supported by the rotation center axis J at the position of the center C1 and is connected to the bottom plate 22b of the housing main body 22 (see FIGS. 1 and 5).

[0032] Furthermore, a pump space Sp is formed between the external gear 453 of the inner rotor 450 and the internal gear 434 of the outer rotor 430. As shown in FIG. 9, when the outer rotor 430 and the inner rotor 450 rotate counterclockwise (see the white arrow), the pump space Sp can move on the bottom plate 22b of the housing main body 22 along the arc-shaped suction hole 25 and discharge hole 26 formed in the bottom plate 22b. Thereby, the fluid (oil) sucked into the pump space Sp from the suction hole 25 is discharged to the outside through the discharge hole 26 from the pump space Sp. Here, the opening areas of the suction hole 25 and the discharge hole 26 formed in the bottom plate 22b of the housing main body 22 are set to be 10 times or more the opening areas of the cooling openings 435a and 435b formed in the ceiling wall portion 435 of the outer rotor 430.

[0033] <Regarding the operation of the electric pump 10> When power is supplied to the controller 50 of the electric pump 10 via the connector 24c of the housing 20, the controller 50 energizes the coil 35 of the stator 30 in a predetermined order. That is, first, the coils 35 of the U phase and the V phase, then the coils 35 of the V phase and the W phase, and then the coils 35 of the W phase and the U phase are energized in order, and this energization is repeated. As a result, the magnetic flux φ generated in the coil 35 rotates counterclockwise at a constant speed.

[0034] When the magnetic flux φ is passed through a magnetic circuit composed of the stationary-side magnetic body 310 of the stator 30 and the rotating-side magnetic body 437 of the outer rotor 430, an eddy current I flows through the rotor main body 431 of the outer rotor 430 due to the magnetic flux φ. As a result, an electromagnetic force is generated between the magnetic flux φ and the eddy current I, and the outer rotor 430 rotates (rotates counterclockwise) in the rotational direction of the magnetic flux φ generated by the coil 35 of the stator 30.

[0035] As a result, as shown in FIG. 9, the outer rotor 430, the inner rotor 450, and the pump space Sp rotate integrally counterclockwise, and the pump space Sp moves along the arc-shaped suction hole 25 and discharge hole 26 formed in the bottom plate 22b of the housing main body 22. As a result, the fluid (oil) sucked into the pump space Sp from the suction hole 25 is discharged to the outside through the discharge hole 26 from the pump space Sp. Here, when the fluid is sucked into the pump space Sp from the suction hole 25, the fluid in the housing inner space Su near the controller 50 is sucked through the cooling opening 435a of the ceiling wall portion 435. Further, when the fluid is discharged from the discharge hole 26, the fluid is discharged into the housing inner space Su near the controller 50 through the cooling opening 435b of the ceiling wall portion 435. As a result, the controller 50 is cooled by the fluid.

[0036] <Correspondence of terms between the electric pump 10 according to the present embodiment and the electric pump according to the present invention> The rotor main body 431 of the outer rotor 430 in the electric pump 10 according to the present embodiment corresponds to the conductor of the outer rotor in the present invention. Further, the pump space Sp corresponds to the space formed between the inner gear of the outer rotor and the outer gear of the inner rotor. Furthermore, the ceiling wall portion 435 of the rotor main body 431 corresponds to the wall portion closing the axial end of the inner gear space of the outer rotor in the present invention.

[0037] <Advantages of the electric pump 10 according to the present embodiment> According to the electric pump 10 according to this embodiment, the outer rotor 430 that constitutes the rotor 40 of the axial gap motor is accommodated in the rotor housing chamber 22h coaxially with the stator 30 and in a state where it cannot be displaced in the radial direction. That is, by being accommodated in the rotor housing chamber 22h, the outer rotor 430 does not require a rotor shaft for holding it coaxially with the stator 30 as in the prior art. Further, the inner rotor 450 that constitutes the rotor 40 is accommodated in the internal gear space S of the outer rotor 430 in a state where it cannot be displaced radially outward and is eccentric with respect to the central axis C0 of the outer rotor 430, and is partially meshed with the internal gear 434 of the outer rotor 430. For this reason, the inner rotor 450 cannot rotate relative to the outer rotor 430 and rotates integrally with the outer rotor 430. In this way, since it is not necessary to provide a bearing portion for the rotor shaft on the stator 30 side of the axial gap motor, the dimensional reduction in the axial direction of the electric pump 10 can be achieved.

[0038] Also, since the rotor main body portion 431 (conductor) of the outer rotor 430 is formed to have a larger diameter than the ring portion 438 of the rotating-side magnetic body 437, an eddy current I easily flows around the salient pole portion 439 of the rotating-side magnetic body 437. Further, the opening areas of the suction hole 25 and the discharge hole 26 formed in the bottom plate 22b of the housing main body portion 22 are set to be 10 times or more the opening areas of the cooling openings 435a and 435b formed in the ceiling wall portion 435 of the outer rotor 430. For this reason, even if fluid is used for cooling the controller 50, it does not significantly affect the pump performance of the electric pump 10.

[0039] <Modified Example> Here, the present invention is not limited to the above-described embodiments, and modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, an induction motor type axial gap motor in which the outer rotor 430 is composed of a rotor main body portion 431 that is a conductor and a rotating side magnetic body 437 made of electromagnetic steel sheets is exemplified. However, as shown in FIG. 10, it is also possible to use a brushless motor type axial gap motor in which the outer rotor 430 is composed of a rotor main body portion 431 made of an insulator and a plurality of pole permanent magnets 60.

[0040] <Other modification examples> Further, in the present embodiment, an axial gap motor including a stator 30 having six coils 35 and an outer rotor 430 having eight salient pole portions 439 is exemplified. However, the number of coils of the stator 30 and the number of salient pole portions of the outer rotor 430 can be appropriately changed.

Explanation of reference numerals

[0041] 10 ··· Electric pump 20 ··· Housing 22 ··· Housing main body portion 22h ··· Rotor housing chamber 22b ··· Bottom plate 25 ··· Suction hole 26 ··· Discharge hole 30 ··· Stator 310 ··· Fixed side magnetic body 312 ··· Fixed side ring portion 314 ··· Salient pole portion 35 ··· Coil 40 ··· Rotor 430 ··· Outer rotor 431 ··· Rotor main body portion (conductor) 434m ··· Tooth groove 434 ··· Internal gear 435 ··· Ceiling wall portion (wall portion closing the axial end of the internal gear space) 435a ··· Cooling opening 435b ··· Cooling opening 437 ··· Rotating side magnetic body 438 ··· Ring part 439 ··· salient pole part 450 ··· inner rotor 453t ··· external teeth 453 ··· external gear 50 ····· controller 52 ····· electric circuit board S ····· internal gear space Sp ····· pump space (space)

Claims

1. An electric pump using an axial gap motor in which a stator and a rotor are arranged to face each other in the axial direction, The rotor includes an inner gear type outer rotor and an outer gear type inner rotor, The outer rotor is coaxially arranged with the stator and is housed in a rotor housing chamber in a state where it cannot be displaced in the radial direction, The inner rotor is housed in the inner gear space of the outer rotor in a state where it cannot be displaced in the radial direction and is eccentric with respect to the central axis of the outer rotor, and is partially meshed with the inner gear of the outer rotor, A space is formed between the inner gear of the outer rotor and the outer gear of the inner rotor, An electric pump in which the outer rotor, the inner rotor, and the space rotate integrally to constitute a pump section in the rotor housing chamber.

2. The electric pump according to claim 1, The stator includes a fixed-side ring portion, a fixed-side magnetic body composed of a plurality of salient pole portions provided at equal intervals in the circumferential direction of the fixed-side ring portion, coils wound around each salient pole portion of the fixed-side magnetic body, and a controller capable of switching energization in a predetermined order for the plurality of coils, The outer rotor of the rotor includes a ring portion provided coaxially with the fixed-side ring portion of the stator, and a plurality of salient pole portions provided at equal intervals in the circumferential direction of the ring portion and facing the salient pole portions of the stator, and a conductor covering the ring portion while surrounding the plurality of salient pole portions of the rotating-side magnetic body, The conductor is concentric with the rotating-side magnetic body and is formed with a diameter larger by a certain dimension than the rotating-side magnetic body.

3. The electric pump according to any one of claims 1 or 2, In the wall portion closing the axial end of the internal gear space of the outer rotor, a cooling opening is formed to guide a part of the fluid in the space formed between the internal gear of the outer rotor and the external gear of the inner rotor to the position of the controller. An electric pump.

4. The electric pump according to claim 3, In the housing constituting the rotor accommodation chamber, a suction hole for supplying fluid into the rotor accommodation chamber and a discharge hole for discharging the fluid in the rotor accommodation chamber are formed. The electric pump in which the opening areas of the suction hole and the discharge hole are set to be 10 times or more of the opening area of the cooling opening formed in the outer rotor.

5. The electric pump according to claim 1, An electric pump configured to be able to pump a fluid capable of cooling a drive motor of an electric vehicle.

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