Electric pump

Abstract

The utility model relates to an electric pump, a rotor is provided with an inner tooth gear type outer rotor (430) and an outer tooth gear type inner rotor (450), and the outer rotor (430) is contained in a rotor containing chamber in the state that the outer rotor (430) is coaxial with a stator and cannot move in the radial direction. The inner rotor (450) is housed in an internally toothed gear space of the outer rotor (430) so as not to be displaced in the radial direction and so as to be eccentric with respect to the central axis of the outer rotor (430), and is partially engaged with an internally toothed gear (434) of the outer rotor (430), and a space (Sp) is formed between the internally toothed gear (434) of the outer rotor (430) and an externally toothed gear (453) of the inner rotor (450). The outer rotor (430), the inner rotor (450), and the space (Sp) integrally rotate, thereby forming a pump part in the rotor accommodating chamber. A rotor shaft of the rotor is not required, thereby achieving a size reduction in the axial direction of the electric pump.

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] Patent Document 1 describes a technique related to the above-mentioned electric pump. Figure 11 、 Figure 12 As shown, the electric pump 100 described in Patent Document 1 is composed of a pump unit 110 and a motor unit 120. The pump unit 110 includes a substantially cylindrical pump chamber 113 formed in the center of a housing 112, and a suction port 114 and a discharge port 115 connected to the pump chamber 113. A disc-shaped rotor 122 is housed in the pump chamber 113 in an eccentric state relative to the pump chamber 113 and in a state rotatable around a rotor shaft 123. The rotor 122 is a portion of the rotor that constitutes the motor unit 120 (axial gap motor), as shown in FIG. Figure 11 As shown, the magnet is magnetized into two poles, the north pole and the south pole, each having a semicircular size.

[0003] Vane grooves (not shown) are formed at the 0° and 180° positions on the outer periphery of the rotor 122. Vanes 124 are mounted in these vane grooves so as to protrude radially outward by magnetic force and to be accommodated in the vane grooves by receiving a radially inward pressing force. In addition, a stator 126 of the motor unit 120 is mounted coaxially with the rotor 122 on the lower side of the housing 112 of the pump unit 110. That is, the stator 126 of the motor unit 120 and the rotor 122 are coaxially connected by the rotor shaft 123. The stator 126 is composed of three coils 127 that generate a magnetic field, a back yoke 128, and a circuit unit 129 that energizes the coils 127 in a predetermined order. Thus, the rotor 122 rotates around the rotor shaft 123 by the magnetic flux generated by the coils 127 and the operation of the permanent magnets of the rotor 122, thereby driving the electric pump 100.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-51611 Utility Model Content

[0007] Problems to be solved by utility models

[0008] The rotor 122 constituting the pump unit 110 and the stator 126 of the motor unit 120 of the electric pump 100 are connected to each other coaxially by the rotor shaft 123. Figure 12As shown, stator 126 of motor unit 120 requires a bearing portion for rotatably supporting rotor shaft 123. Therefore, even if the axial (vertical) size of electric pump 100 is reduced by using an axial gap motor, the presence of the bearing portion for rotor shaft 123 on the stator 126 side limits the reduction in axial size of electric pump 100.

[0009] The present technology has been developed to solve the above-mentioned problems. The problem to be solved by the present invention is to reduce the axial size of the electric pump by eliminating the need for a bearing portion of the rotor shaft on the stator side of the motor unit.

[0010] Solutions for solving problems

[0011] The above-mentioned problems are solved by various technical solutions. The first technical solution is an electric pump using an axial gap motor in which a stator and a rotor are arranged axially opposite to each other, characterized in that the rotor includes an outer rotor with an internal gear and an inner rotor with an external gear, the outer rotor being accommodated in a rotor accommodation chamber in a state coaxial with the stator and unable to be displaced in the radial direction, the inner rotor being accommodated in a space of the internal gear of the outer rotor in a state unable to be displaced in the radial direction and eccentric with respect to the central axis of the outer rotor, and partially meshing with the internal gear of the outer rotor, a space being formed between the internal gear of the outer rotor and the external gear of the inner rotor, and the outer rotor, the inner rotor, and the space being rotated integrally, thereby forming a pump portion in the rotor accommodation chamber.

[0012] According to the above technical solution, the outer rotor that constitutes the rotor of the axial gap motor is housed in the rotor housing chamber, coaxial with the stator and unable to displace radially. That is, by housing the outer rotor in the rotor housing chamber, the need for a rotor shaft that is conventionally maintained coaxial with the stator is eliminated. Furthermore, the inner rotor that constitutes the rotor is housed within the internal gear space of the outer rotor, unable to displace radially outward and eccentric with respect to the center axis of the outer rotor, and partially meshes with the internal gear of the outer rotor. Therefore, the inner rotor cannot rotate relative to the outer rotor and rotates integrally with it. This eliminates the need for a rotor shaft bearing on the stator side of the axial gap motor, allowing the electric pump to be reduced in axial dimensions.

[0013] According to the second technical solution, the stator comprises: a fixed-side magnetic body, which includes a fixed-side ring portion and a salient pole portion, and the salient pole portion is provided in plurality at equal intervals in the circumferential direction of the fixed-side ring portion; a coil, which is wound around each salient pole portion of the fixed-side magnetic body; and a controller, which can switch the power supply to the plurality of coils in a predetermined order, and the outer rotor of the rotor comprises: a rotating-side magnetic body, which includes a ring portion and a salient pole portion, the ring portion is coaxially arranged with the fixed-side ring portion of the stator, the salient pole portion is provided in plurality at equal intervals in the circumferential direction of the ring portion and is opposite to the salient pole portion of the stator; and a conductor, which covers the ring portion in a state of surrounding the plurality of salient pole portions of the rotating-side magnetic body, the conductor being formed concentrically with the rotating-side magnetic body, and the diameter of the conductor being a certain size larger than the diameter of the rotating-side magnetic body.

[0014] According to the above technical solution, the magnetic flux generated by the stator coil passes from the salient pole portion of the stator's fixed-side magnetic body through the salient pole portion of the outer rotor's rotating-side magnetic body. As a result, eddy currents flow through the outer rotor's electrical conductors, surrounding the salient pole portion of the rotating-side magnetic body. As a result, a force is generated between the magnetic flux and the eddy currents in a direction that causes the outer rotor to rotate. Here, the outer rotor's electrical conductor is formed concentrically with the rotating-side magnetic body, and its diameter is a certain size larger than the diameter of the rotating-side magnetic body. Therefore, the eddy currents tend to flow in a manner that surrounds the salient pole portion of the rotating-side magnetic body.

[0015] According to the third technical solution, a cooling opening is formed in the wall portion of the outer rotor at the axial end that closes the space for the internal gear. This cooling opening directs a portion of the fluid in the space between the internal gear of the outer rotor and the external gear of the inner rotor toward the location of the controller. Therefore, the controller can be cooled using the fluid directed from the cooling opening to the location of the controller.

[0016] According to the fourth invention, the housing forming the rotor housing chamber includes an intake hole for supplying fluid into the rotor housing chamber and an exhaust hole for discharging fluid from the rotor housing chamber. The opening areas of the intake and exhaust holes are set to be at least 10 times the opening area of ​​the cooling opening formed in the outer rotor. Therefore, even if the fluid is used to cool the controller, pump performance is not significantly affected.

[0017] The electric pump according to the fifth aspect is configured to be capable of pressurizing and delivering a fluid capable of cooling a drive motor of an electric vehicle.

[0018] Effect of utility model

[0019] According to the technology of the present application, since a bearing portion of the rotor shaft on the stator side is unnecessary, the axial dimension of the electric pump using the axial gap motor can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic longitudinal sectional view of an electric pump using an axial gap motor according to the first embodiment of the present invention.

[0021] Figure 2 is a top view of the stator and housing of the axial gap motor ( Figure 1 II-II view).

[0022] Figure 3 This is a top cross-sectional view showing the coils and the like of the stator of the axial gap motor ( Figure 1 (III-III view).

[0023] Figure 4 This is a top view of the rotor (outer rotor) and housing of the axial gap motor ( Figure 1 (IV-IV view).

[0024] Figure 5 is a top sectional view of the outer rotor and inner rotor of the rotor of the axial gap motor ( Figure 1 (VV view).

[0025] Figure 6 is a top sectional view of the outer rotor and inner rotor of the axial gap motor ( Figure 1 VI-VI view).

[0026] Figure 7 This is a schematic longitudinal sectional view showing a developed magnetic circuit between the stator and the rotor of the axial gap motor.

[0027] Figure 8 This is a schematic top cross-sectional view showing eddy currents generated in the rotor (outer rotor) of the axial gap motor.

[0028] Figure 9 It is a top cross-sectional view showing the operation of the pump portion of the electric pump.

[0029] Figure 10 This is a top cross-sectional view of an electric pump using an axial gap motor according to Modification Example 1.

[0030] Figure 11 This is a perspective view of a conventional electric pump using an axial gap motor.

[0031] Figure 12 This is a longitudinal sectional view of a conventional electric pump using an axial gap motor.

[0032] Description of Reference Numerals

[0033] 10. Electric pump; 20. Housing; 22. Housing body; 22h. Rotor accommodating chamber; 22b. Bottom plate; 25. Intake hole; 26. Discharge hole; 30. Stator; 310. Fixed-side magnetic body; 312. Fixed-side ring; 314. Salient pole; 35. Coil; 40. Rotor; 430. Outer rotor; 431. Rotor body (conductor); 434m. Tooth groove; 434. Internal gear; 435. Top wall (wall that blocks the axial end of the internal gear space); 435a. Cooling opening; 435b. Cooling opening; 437. Rotating-side magnetic body; 438. Ring; 439. Salient pole; 450. Inner rotor; 453t. External teeth; 453. External gear; 50. Controller; 52. Circuit board; S. Internal gear space; Sp. Pump space (space). DETAILED DESCRIPTION

[0034] [Implementation Method 1]

[0035] The following is based on Figures 1 to 10 The electric pump according to Embodiment 1 of the present invention will now be described. The electric pump 10 of this embodiment utilizes an axial gap motor and pressurizes and delivers oil for lubrication and cooling to the drive motor of an electric vehicle. The front, back, left, right, and top and bottom in the accompanying drawings correspond to the front, back, left, right, and top and bottom of the electric pump 10.

[0036] <Overview of the Electric Pump 10>

[0037] like Figure 1 As shown, the electric pump 10 is a pump using an axial gap motor in which a stator 30 and a rotor 40 are arranged facing each other in the axial direction (vertical direction). The rotor 40 constitutes a pump unit (a cycloid pump) within a housing 20. The electric pump 10 includes a housing 20, which is a cylindrical container; a stator 30 coaxially housed in the upper half of the housing 20; a rotor 40 coaxially housed in the lower half of the housing 20; and a controller 50 housed in the upper center opening of the stator 30.

[0038] <About Housing 20>

[0039] like Figure 1 As shown, the housing 20 is composed of a bottomed cylindrical housing body 22 and a disc-shaped cover 24 that closes the upper opening of the housing body 22. An annular shelf-like inner flange 22f is formed on the inner wall surface of the housing body 22 at a position a certain size downward from the upper opening. The inner flange 22f of the housing body 22 supports the periphery of the stator 30 of the axial gap motor from below. In addition, the rotor 40 of the axial gap motor is accommodated on the lower side of the inner flange 22f of the housing body 22. In other words, the lower side of the inner flange 22f of the housing body 22 forms a rotor accommodation chamber 22h that accommodates the rotor 40.

[0040] like Figure 4 As shown in Figures 2 and 3, the inner diameter of the rotor accommodation chamber 22h of the housing body 22 is set larger than the outer diameter of the rotor 40 (outer rotor 430) by an amount equivalent to the clearance. In other words, the outer rotor 430 of the rotor 40 is radially constrained from the outside by the inner wall of the rotor accommodation chamber 22h of the housing body 22. Therefore, even without a rotational center axis, the outer rotor 430 cannot displace radially and can rotate coaxially with the stator 30.

[0041] like Figure 1 As shown, the bottom plate 22b of the housing body 22 is formed with an intake hole 25 for supplying oil to a pump unit (described later) composed of the rotor accommodation chamber 22h and the rotor 40 (outer rotor 430, inner rotor 450) and a discharge hole 26 for discharging oil. Figure 4 As shown in FIG. 1 , the suction hole 25 is formed in an arc shape on the front side of the central portion of the bottom plate 22b of the housing body 22 in a manner surrounding the center. In addition, the discharge hole 26 is also formed in an arc shape on the rear side of the central portion of the bottom plate 22b of the housing body 22 in a manner surrounding the center. Moreover, a bearing hole (illustration mark omitted) is formed on the bottom plate 22b of the housing body 22 to support the lower end of the rotation center axis J of the inner rotor 450. Figure 1 As shown, a connector 24c for supplying power to the controller 50 is provided in an upwardly protruding manner at the rear of the cover 24 that closes the upper opening of the housing body 22. The housing 20 is formed of a resin such as plastic.

[0042] <About Stator 30>

[0043] like Figures 1 to 3 As shown, the stator 30 includes a fixed-side magnetic body 310 and a plurality of (six in the figure) coils 35. The fixed-side magnetic body 310 is formed by stacking thin electromagnetic steel sheets in the axial direction. The fixed-side magnetic body 310 is composed of an annular fixed-side ring portion 312 and a salient pole portion 314. The salient pole portion 314 protrudes axially from the lower surface of the fixed-side ring portion 312, and is provided with a plurality of (six in the figure) equidistantly in the circumferential direction of the fixed-side ring portion 312. And, as shown in FIG. Figure 3 As shown in FIG. 3 , the coil 35 is wound around each salient pole portion 314 of the fixed side magnetic body 310. Figure 1 As shown, the periphery of the stationary-side ring portion 312 of the stationary-side magnetic body 310 of the stator 30 is placed on the inner flange portion 22f of the housing body 22. Furthermore, the salient pole portions 314 and coils 35 of the stator 30 protrude downward through the opening of the inner flange portion 22f of the housing body 22. Here, the stationary-side magnetic body 310 can also be formed using a powder core instead of stacking electromagnetic steel sheets.

[0044] <About controller 50>

[0045] like Figure 1 As shown, the controller 50 is housed in the circular opening 316 of the fixed side ring portion 312 of the fixed side magnetic body 310 of the stator 30 in a state covered by the disc-shaped cover member 54. Figure 3 As shown in FIG. 1 , the controller 50 is configured to energize the U-phase coil 35, the V-phase coil 35, and the W-phase coil 35 used in pairs in a predetermined order. In the electric pump 10 of this embodiment, first, Figure 3 The U-phase and V-phase coils 35 are energized, followed by the V-phase and W-phase coils 35, and then the W-phase and U-phase coils 35. This energizing sequence is repeated. As a result, the magnetic flux generated by the coils 35 rotates counterclockwise at a constant speed.

[0046] like Figure 1 As shown, the controller 50 is mounted in the center of a circular circuit board 52. The periphery of the circuit board 52 covers the fixed-side ring portion 312 of the fixed-side magnetic body 310 of the stator 30. Furthermore, the conductive portion of the circuit board 52 is connected to the connector 24c of the housing 20. Furthermore, the cover member 54 covering the controller 50 is formed of a material with high heat dissipation properties.

[0047] <About Rotor 40>

[0048] like Figure 1 、 Figure 5 As shown in FIG. 1 , the rotor 40 is composed of an outer rotor 430 and an inner rotor 450. Figure 5 In the figures, the housing body 22 is omitted. The outer rotor 430 includes: a rotating side magnetic body 437, which is formed by laminating thin plate-shaped electromagnetic steel plates in the axial direction; and a rotor body 431, which is an aluminum alloy conductor that supports the rotating side magnetic body 437 in a state of covering the rotating side magnetic body 437. As described above, the rotor body 431 of the outer rotor 430 is held in a state of being rotatable about the axis within the rotor accommodation chamber 22h of the housing body 22 (see Figure 1 、 Figure 4 ).

[0049] <Regarding the Rotor Main Body 431 of the Outer Rotor 430>

[0050] like Figure 1 As shown, a cylindrical vertical wall portion 432 is provided on the outer periphery of the rotor body portion 431 of the outer rotor 430, which is embedded between the inner flange portion 22f of the housing body portion 22 and the bottom plate 22b to prevent the outer rotor 430 from moving in the axial direction. Figure 4As shown, a magnetic body support portion 433 in which a rotating-side magnetic body 437 is embedded is formed annularly on the radially inner side of a cylindrical vertical wall portion 432 of a rotor body portion 431 .

[0051] In addition, if Figure 5 As shown in FIG. 1 , an internal gear 434 is formed on the radially inner side of the magnetic support portion 433 in the rotor body 431 of the outer rotor 430. Seven tooth grooves 434m are formed in the internal gear 434 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 in the central part of the rotor body 431. Figure 1 and Figure 4 As shown, the rotor body 431 is provided with a top wall portion 435 that closes the upper opening of the internal gear space S formed by the internal gear 434. Furthermore, the top wall portion 435 of the rotor body 431 is formed with a pair of cooling openings 435a and 435b that connect the internal gear space S of the rotor body 431 with the space Su within the housing near the controller 50.

[0052] <Regarding the Rotating-Side Magnetic Body 437 of the Outer Rotor 430>

[0053] like Figures 4 to 6 and Figure 7 As shown, the rotating side magnetic body 437 of the outer rotor 430 is composed of a ring portion 438 and a salient pole portion 439. The salient pole portion 439 protrudes axially from the upper surface of the ring portion 438 and is provided in multiple numbers (eight in the figure) at equal intervals in the circumferential direction of the ring portion 438. Furthermore, the rotating side magnetic body 437 is embedded in the magnetic body support portion 433 of the rotor main body 431 as a conductor from the ring portion 438 to the vicinity of the top end of the salient pole portion 439 (see FIG. Figure 1 wait).

[0054] Therefore, if Figure 7 As shown in the schematic expansion diagram of FIG, the magnetic flux φ ( Figure 7 The white arrows (shown in FIG. 1 ) pass through the magnetic circuit formed by the fixed side magnetic body 310 of the stator 30 and the rotating side magnetic body 437 of the outer rotor 430. Figure 8As shown, eddy currents I flow around the salient poles 439 of the rotating-side magnetic body 437 of the outer rotor 430 (the rotor body 431, which is a conductive body). As a result, electromagnetic force is generated between the magnetic flux φ and the eddy currents I, causing the outer rotor 430 to rotate in the direction of the magnetic flux φ generated by the coils 35 of the stator 30. The diameter of the rotor body 431 of the outer rotor 430 is larger than the diameter of the ring portion 438 of the rotating-side magnetic body 437. This facilitates the eddy currents I to flow around the salient poles 439 of the rotating-side magnetic body 437. Alternatively, the rotating-side magnetic body 437 can be formed of a pressed powder core instead of electromagnetic steel sheets.

[0055] <About Inner Rotor 450>

[0056] like Figure 5 As shown in FIG. 1 , the inner rotor 450 is an external gear type rotor that forms a cycloid 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 spaced evenly in the circumferential direction. In addition, the axial length of the external gear 453 (in Figure 1 (height dimension) is set to a value equal to the axial length dimension of the internal gear 434 of the outer rotor 430. Figure 1 As shown, the inner rotor 450 is clamped and restrained by the top wall portion 435 of the outer rotor 430 and the bottom plate 22 b of the housing body portion 22 from the top and bottom directions (axial direction).

[0057] The three consecutive external teeth 453t of the external gear 453 of the inner rotor 450 (at Figure 5 The outer teeth 453t (the upper outer teeth 453t in the middle) mesh with the three tooth grooves 434m of the internal gear 434 of the outer rotor 430. Furthermore, the tips of the outer teeth 453t (the lower outer teeth 453t) located on the opposite side of the center outer tooth 453t of the three external teeth 453t of the external gear 453 abut against the inner circumferential surface of the internal gear 434.

[0058] Thus, the inner rotor 450 is housed in the internal gear space S of the outer rotor 430 in an eccentric state relative to the outer rotor 430, and is constrained from the outside in the radial direction. That is, the center C1 of the inner rotor 450 is eccentric from the center axis C0 of the outer rotor 430. In addition, the inner rotor 450 is held so as not to rotate relative to the outer rotor 430 in the circumferential direction. That is, the inner rotor 450 rotates integrally with the outer rotor 430. The position of the center C1 of the inner rotor 450 is supported by the above-mentioned rotation center axis J so as to be rotatable, so that the inner rotor 450 is connected to the bottom plate 22b of the housing body 22 (see Figure 1 、 Figure 5 ).

[0059] 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. Figure 9 As shown, when the outer rotor 430 and inner rotor 450 rotate counterclockwise (see white arrows), the pump space Sp can move along the arcuate suction hole 25 and discharge hole 26 formed on the bottom plate 22b of the housing body 22. Consequently, the fluid (oil) drawn into the pump space Sp through the suction hole 25 is discharged from the pump space Sp to the outside through the discharge hole 26. The opening area of ​​the suction hole 25 and discharge hole 26 formed in the bottom plate 22b of the housing body 22 is set to be at least 10 times the opening area of ​​the cooling openings 435a and 435b formed in the top wall 435 of the outer rotor 430.

[0060] <About Operation of Electric Pump 10>

[0061] 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 coils 35 of the stator 30 in a predetermined order. Specifically, the coils 35 for the U and V phases are energized first, followed by the coils 35 for the V and W phases, and finally the coils 35 for the W and U phases. This energization is repeated in this order. As a result, the magnetic flux φ generated by the coils 35 rotates counterclockwise at a constant speed.

[0062] When magnetic flux φ passes through the magnetic circuit formed by the stationary-side magnetic body 310 of the stator 30 and the rotating-side magnetic body 437 of the outer rotor 430, eddy currents I flow through the rotor body 431 of the outer rotor 430 due to magnetic flux φ. As a result, electromagnetic force is generated between magnetic flux φ and eddy currents I, causing the outer rotor 430 to rotate in the direction of rotation of magnetic flux φ generated by the coils 35 of the stator 30 (counterclockwise).

[0063] Therefore, if Figure 9 As shown, the outer rotor 430, the inner rotor 450, and the pump space Sp rotate counterclockwise as a whole, 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 body 22. As a result, the fluid (oil) sucked into the pump space Sp from the suction hole 25 is discharged from the pump space Sp to the outside through the discharge hole 26. 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 top wall portion 435. In addition, 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 top wall portion 435. As a result, the controller 50 is cooled by the fluid.

[0064] <Correspondence of terms between the electric pump 10 of the present embodiment and the electric pump of the present utility model application>

[0065] The rotor body 431 of the outer rotor 430 in the electric pump 10 of this embodiment corresponds to the outer rotor's electrical conductor in the present invention. Furthermore, the pump space Sp corresponds to the space formed between the outer rotor's internal gear and the inner rotor's external gear. Furthermore, the top wall 435 of the rotor body 431 corresponds to the axial end wall of the outer rotor that closes the space between the internal gears in the present invention.

[0066] <Advantages of the Electric Pump 10 of the Present Embodiment>

[0067] According to the electric pump 10 of this embodiment, the outer rotor 430, which constitutes the rotor 40 of the axial gap motor, is housed in the rotor housing chamber 22h in a coaxial state with the stator 30 and in a non-displaceable radial position. Specifically, by housing the outer rotor 430 in the rotor housing chamber 22h, the conventional rotor shaft, which is held coaxial with the stator 30, is no longer required. Furthermore, the inner rotor 450, which constitutes the rotor 40, is housed in the internal gear space S of the outer rotor 430 in a non-displaceable radially outward state and eccentric with respect to the center axis C0 of the outer rotor 430. It partially meshes with the internal gear 434 of the outer rotor 430. Consequently, the inner rotor 450 cannot rotate relative to the outer rotor 430 and rotates integrally with the outer rotor 430. This eliminates the need for a rotor shaft bearing on the stator 30 side of the axial gap motor, thereby reducing the axial size of the electric pump 10.

[0068] Furthermore, the diameter of the rotor body 431 (conductor) of the outer rotor 430 is larger than the diameter of the ring portion 438 of the rotating-side magnetic body 437. This facilitates the flow of eddy currents I around the salient pole portions 439 of the rotating-side magnetic body 437. Furthermore, the opening areas of the intake holes 25 and discharge holes 26 formed in the bottom plate 22b of the housing body 22 are set to be at least ten times the opening area of ​​the cooling openings 435a and 435b formed in the top wall 435 of the outer rotor 430. Therefore, even if fluid is used to cool the controller 50, the pump performance of the electric pump 10 is not significantly affected.

[0069] <Change Example>

[0070] Here, the present invention is not limited to the above-mentioned embodiment, and modifications can be made within the scope of the main purpose of the present invention. For example, in this embodiment, an induction motor type axial gap motor is illustrated in which the outer rotor 430 is composed of a rotor main body 431 as a conductor and a rotating side magnetic body 437 made of electromagnetic steel sheet. However, if Figure 10 As shown, a brushless motor type axial gap motor in which the outer rotor 430 is composed of a rotor body 431 made of an insulator and a permanent magnet 60 having multiple poles can also be used.

[0071] Other changes

[0072] In this embodiment, an axial gap motor including a stator 30 having six coils 35 and an outer rotor 430 having eight salient poles 439 is exemplified. However, the number of coils in the stator 30 and the number of salient poles in the outer rotor 430 can be changed as appropriate.

Claims

1. An electric pump using an axial gap motor in which a stator and a rotor are arranged opposite to each other in the axial direction, characterized in that: The rotor includes an inner gear type outer rotor and an outer gear type inner rotor. The outer rotor is housed in the rotor housing chamber in a state where the outer rotor is coaxial with the stator and cannot be displaced in the radial direction. The inner rotor is accommodated 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 partially meshes with the inner gear of the outer rotor. A space is formed between the internal gear of the outer rotor and the external gear of the inner rotor. The outer rotor, the inner rotor, and the space rotate integrally, thereby forming a pump portion in the rotor accommodation chamber.

2. The electric pump according to claim 1, characterized in that The stator comprises: a fixed-side magnetic body including a fixed-side ring portion and a salient pole portion, wherein a plurality of salient pole portions are provided at equal intervals in the circumferential direction of the fixed-side ring portion; a coil wound around each salient pole portion of the fixed-side magnetic body; and a controller capable of switching power to the plurality of coils in a predetermined order. The outer rotor of the rotor comprises: a rotating-side magnetic body including a ring portion and a salient pole portion, the ring portion being coaxially arranged with the fixed-side ring portion of the stator, the salient pole portion being provided in plurality at equal intervals in the circumferential direction of the ring portion and facing the salient pole portion of the stator; and a conductor covering the ring portion so as to surround the plurality of salient pole portions of the rotating-side magnetic body, The conductor is formed concentrically with the rotating-side magnetic body, and the diameter of the conductor is larger than the diameter of the rotating-side magnetic body by a certain dimension.

3. The electric pump according to claim 2, characterized in that A cooling opening is formed in a wall portion of an axial end of the outer rotor that closes the internal gear space. The cooling opening guides a portion of the fluid in the space formed between the internal gear of the outer rotor and the external gear of the inner rotor toward the position of the controller.

4. The electric pump according to claim 3, characterized in that The housing constituting the rotor housing chamber is provided with a suction hole for supplying fluid into the rotor housing chamber and a discharge hole for discharging the fluid from the rotor housing chamber. 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.

5. The electric pump according to claim 1, characterized in that The electric pump is configured to pump a fluid under pressure for cooling a drive motor of an electric vehicle.

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