Pump Assembly

Abstract

This pump assembly is provided with: an axial gap motor having a first stator, a motor rotor, and a motor shaft; and a first pump having a first pump rotor configured to be rotated by the motor rotor. The first stator is provided with a first annular yoke and a plurality of first teeth disposed on a first surface of the first yoke. The first pump is disposed in a first inner space surrounded by the plurality of first teeth.

Description

[Technical Field]

[0001] The present disclosure relates to a pump assembly. This application claims priority based on Japanese Patent Application No. 2022-202207 filed on December 19, 2022, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] An axial gap motor has a stator, a motor rotor, and a motor shaft. In an axial gap motor, the magnetic flux from the stator to the rotor flows parallel to the axis of the motor shaft. An axial gap motor has the advantage of being short in length along the axis.

[0003] Patent Document 1 discloses a pump assembly that combines an axial gap motor and an electric pump that pumps a fluid. In this pump assembly, the axial gap motor and the electric pump are arranged side by side in a direction along the axis of the motor shaft. This pump assembly is compact, taking advantage of the axial gap motor's small size along the axis. In pump assemblies that use a radial gap motor, the size along the axis of the motor shaft is large. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-182269 Summary of the Invention

[0005] The pump assembly of the present disclosure includes an axial gap motor having a first stator, a motor rotor, and a motor shaft, and a first pump having a first pump rotor configured to be rotated by the motor rotor. The first stator includes a first annular yoke and a plurality of first teeth arranged on a first surface of the first yoke. The first pump is arranged in a first internal space surrounded by the plurality of first teeth. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic perspective view of a pump assembly according to a first embodiment. [Figure 2] FIG. 2 is a schematic plan view of the pump assembly according to the first embodiment. [Figure 3] FIG. 3 is a schematic exploded perspective view of an axial gap motor provided in the pump assembly according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating the arrangement of the first pump in the pump assembly according to the first embodiment. [Figure 5] 5 is a cross-sectional view of the pump assembly of the first embodiment taken along the VV cutting line shown in FIG. [Figure 6] 6 is a cross-sectional view of the pump assembly of the first embodiment taken along the line VI-VI in FIG. [Figure 7] FIG. 7 is a schematic diagram illustrating the arrangement of the first pump in the pump assembly according to the second embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view of a pump assembly according to a third embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view of a pump assembly according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] [Problem to be solved by this disclosure] Pump assemblies are often placed in narrow spaces such as automobiles, and therefore, even when an axial gap motor is used, there is a demand for pump assemblies that are even more compact in length along the axial line.

[0008] SUMMARY OF THE INVENTION One object of the present disclosure is to provide a pump assembly that is more compact in size along the axis of the motor shaft than conventional pump assemblies.

[0009] [Effects of this disclosure] The pump assembly of the present disclosure is more compact than conventional pump assemblies.

[0010] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0011] <1> The pump assembly of the present disclosure includes an axial gap motor having a first stator, a motor rotor, and a motor shaft, and a first pump having a first pump rotor configured to be rotated by the motor rotor. The first stator includes a first annular yoke and a plurality of first teeth arranged on a first surface of the first yoke. The first pump is arranged in a first internal space surrounded by the plurality of first teeth.

[0012] the above <1> In the pump assembly described in the above, a first pump is disposed in a first internal space of an axial gap motor surrounded by a plurality of first teeth. <1> The length of the motor shaft along the axis of the pump assembly described in is smaller than the length of the motor shaft along the axis of the conventional pump assembly.

[0013] the above <1> In the pump assembly described in the above, the first pump is disposed in the first internal space. That is, the first pump is disposed inside the axial gap motor and is surrounded by the components of the axial gap motor. Therefore, the operating noise of the first pump is unlikely to leak outside the pump assembly. <1> The pump assembly described in is excellent in quietness.

[0014] the above <1> In the pump assembly described in the above, heat generated by the axial gap motor easily increases the temperature of the first pump disposed in the first internal space of the axial gap motor. When the temperature of the first pump increases, the temperature of the fluid in the first pump increases and the viscosity of the fluid decreases. As a result, the load on the axial gap motor is reduced, and the power consumption of the axial gap motor is reduced. In particular, after the axial gap motor is started, when the temperature of the fluid is low, the load on the axial gap motor is likely to be reduced early. The first pump disposed in the first internal space has a high thermal capacity due to its structure. Therefore, the first pump easily absorbs heat generated by the axial gap motor, and heat generation by the axial gap motor can be suppressed. The fluid in the present disclosure may be a liquid, a gas, or a mixture of a gas and a liquid.

[0015] <2> the above <1> In the pump assembly described above, the first pump rotor may be coaxially fixed to the motor shaft.

[0016] the above <2> In the pump assembly described in (1), the motor shaft of the motor rotor also serves as the drive shaft of the pump rotor. This reduces the number of parts in the pump assembly, making the pump assembly more compact. Furthermore, because the first pump rotor rotates in perfect synchronization with the rotation of the motor rotor, it is easy to control the rotation speed of the first pump rotor, i.e., the flow rate of the fluid, using the axial gap motor.

[0017] <3> the above <1> or <2> In the pump assembly described in , the first pump may include an inlet port and an outlet port, and the inlet port and the outlet port may be disposed in a first direction as viewed from the first pump rotor, the first direction being along the axis of the motor shaft and away from the motor rotor.

[0018] Since the motor rotor does not exist in the first direction as viewed from the first pump rotor, the inlet port and the outlet port can be easily arranged. In addition, since the inlet port and the outlet port are arranged in the first direction, an increase in the diameter of the stator core is suppressed.

[0019] the above <3> Unlike the configuration described in [2], when the inlet port and the outlet port are arranged in the radial direction, the inlet port and the outlet port are arranged in the gaps between the multiple first teeth arranged on the annular first yoke. The radial direction is a direction perpendicular to the axis of the motor shaft and away from the axis. The inlet port and the outlet port arranged in the radial direction increase the gaps between the multiple first teeth, making it easier to increase the diameter of the stator core.

[0020] <4> the above <1> from <3> In the pump assembly described in any one of the above, the first pump may be an internal gear pump having an external gear and an internal gear, and the external gear may be the first pump rotor.

[0021] An internal gear pump, in which an external gear is disposed inside an internal gear, is compact. This internal gear pump is easy to place in the first internal space, which has size restrictions. Furthermore, the internal gear pump has better space efficiency than other pumps of the same size. Therefore, <4> The pump assembly described in is compact yet easy to increase the flow rate of fluid.

[0022] <5> the above <4> In the pump assembly described in , the axial gap motor may include a motor housing that houses the first stator and the motor rotor, and the internal gear pump may include a pump housing that houses the external gear and the internal gear. The motor housing includes a base portion to which the first yoke is fixed. The pump housing includes a body, a pump cover, and bolts. The body includes a cylindrical portion that covers the outer periphery of the internal gear, a bottom portion that seals a first end face of the cylindrical portion, and an annular flange portion that extends outward from the outer periphery of the cylindrical portion near a second end face of the cylindrical portion. The pump cover seals an opening of the cylindrical portion at the second end face. The bolts fix the pump cover to the annular flange portion. The annular flange portion constitutes the base portion.

[0023] the above <5> In the configuration described in the document, the pump cover of the pump housing is fixed with bolts to an annular flange portion integrated with the body of the pump housing. Therefore, there is no need to provide bolt holes for locating bolts in the cylindrical portion that covers the outer periphery of the internal gear. The cylindrical portion that does not require bolt holes can be made thinner. The thinner cylindrical portion can have a smaller outer diameter or a larger inner diameter. If the outer diameter of the cylindrical portion is reduced without changing the inner diameter of the cylindrical portion, the outer diameter of the pump assembly can be reduced without reducing the capacity of the internal gear pump. If the inner diameter of the cylindrical portion is increased without changing the outer diameter of the cylindrical portion, the capacity of the internal gear pump can be increased without increasing the outer diameter of the pump assembly.

[0024] <6> the above <1> from <3> In the pump assembly described in any one of the above, the first pump may be a vane pump, and the first pump rotor may have a plurality of vanes.

[0025] A vane pump having a first pump rotor with multiple vanes is compact and can be easily placed in the first internal space, which has size restrictions. Furthermore, because the vane pump has excellent sealing properties, it can easily pump gas, liquid, or a mixture of gas and liquid.

[0026] <7> the above <1> from <6> In the pump assembly described in any one of the above, the axial gap motor may further include a second pump having a second pump rotor configured to be rotated by the motor rotor, and the axial gap motor may further include a second stator sandwiching the motor rotor between itself and the first stator. The second stator includes an annular second yoke and a plurality of second teeth arranged on a second surface of the second yoke. The second pump is arranged in a second internal space surrounded by the plurality of second teeth.

[0027] Axial gap motors, in which a single motor rotor is sandwiched between a first stator and a second stator, generate high torque. Such axial gap motors are called single rotor / double stator type axial gap motors. <7> The pump assembly described in the above includes a first pump and a second pump that are independent of each other. <7> The pump assembly described in the above can pump two independent fluid systems. In addition, since the first pump and the second pump are respectively disposed in the first internal space and the second internal space in the axial gap motor, <7> The pump assembly described in is compact.

[0028] [Details of the embodiments of the present disclosure] Specific examples of the pump assembly of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. The dimensions of the components shown in each drawing are expressed for the purpose of clarity and do not necessarily represent actual dimensions. The present invention is not limited to these examples, but is defined by the claims, and all modifications within the meaning and scope of the claims are intended to be included.

[0029] <Embodiment 1> The pump assembly 1 shown in Figures 1 and 2 includes an axial gap motor 2 and a first pump 5. From the outside of the pump assembly 1, the motor housing 29 of the axial gap motor 2 and the pump housing 59 of the first pump 5 are visible. An inlet port 51 and an outlet port 52 open in the pump housing 59. As shown in the plan view of Figure 2, an external gear 55 and an internal gear 56 provided in the first pump 5, which will be described later, can be seen beyond the inlet port 51 and the outlet port 52. Each component of the pump assembly 1 will be described below. In the following description, the "axial gap motor" will be simply referred to as the "motor."

[0030] <Motor> In describing the motor 2, reference will be made primarily to FIG. 3, which is an exploded perspective view of the motor 2, and also to FIGS. 5 and 6, which are cross-sectional views of the pump assembly 1, as necessary. The motor 2 comprises a first stator 4, a motor rotor 3, and a motor shaft 20. As shown in FIGS. 5 and 6, the first stator 4 and the motor rotor 3 are arranged coaxially with the motor shaft 20. The first stator 4 and the motor rotor 3 face each other with a gap in between in the direction along the axis of the motor shaft 20. The motor 2 of this example is a single-rotor, single-stator type motor comprising one first stator 4 and one motor rotor 3.

[0031] The first stator 4 includes a first yoke 40, a plurality of first teeth 41, and a plurality of first coils 42. The first yoke 40 is a plate material formed in an annular shape. The first teeth 41 are columnar. The first teeth 41 protrude from a planar first surface 40s of the first yoke 40. The plurality of first teeth 41 have the same shape and size. Each first tooth 41 has, for example, a rectangular columnar or cylindrical shape. The first stator 4 of this example is formed, for example, from an integrated powder compact. Unlike this example, the first stator 4 may be formed from a plurality of divided pieces.

[0032] An end face of the first tooth 41 faces a magnet 31 of the motor rotor 3, which will be described later. A first coil 42 is disposed on the outer circumferential surface of the first tooth 41. When a current flows through the first coil 42, the first stator 4 is excited, generating a rotating magnetic field. In this example, the end of the winding that constitutes the first coil 42 is not shown.

[0033] The motor rotor 3 includes a base plate 30 and a plurality of magnets 31. The base plate 30 is an annular plate material through which the motor shaft 20 passes. The base plate 30 and the motor shaft 20 are fixed to each other, and the base plate 30 and the motor shaft 20 rotate coaxially. The base plate 30 includes a base surface 30s that faces the first surface 40s of the first yoke 40.

[0034] The multiple magnets 31 are fixed to the base surface 30s, for example, by adhesive. The magnets 31 are permanent magnets. The multiple magnets 31 are arranged at approximately equal intervals around the axis of the motor shaft 20. The shape of the magnets 31 is, for example, flat. The planar shape of the magnets 31, for example, corresponds to the shape of the end faces of the first teeth 41. The magnets 31 are magnetized in a direction along the axis of the motor shaft 20. The magnetization directions of two magnets 31 adjacent to each other around the axis of the motor shaft 20 are opposite to each other. The rotating magnetic field generated in the first stator 4 attracts or repels the magnets 31 to the first teeth 41, causing the motor rotor 3 to rotate relative to the first stator 4.

[0035] As shown in Figure 5, the motor 2 further includes a motor housing 29. The first stator 4 and the motor rotor 3 described above are disposed inside the motor housing 29. A portion of the motor shaft 20 is also disposed inside the motor housing 29. Unlike this example, the entire motor shaft 20 may be disposed inside the motor housing 29.

[0036] The motor housing 29 of this example is composed of a peripheral wall portion 2A, a first cover 2B, and a second cover 2C. The peripheral wall portion 2A is a cylindrical member. The inner diameter of the peripheral wall portion 2A is larger than the outer diameter of the first stator 4. The length of the peripheral wall portion 2A along the motor shaft 20 is larger than the length of the first stator 4 along the motor shaft 20.

[0037] The first cover 2B is a disk-shaped member that seals a first end of the peripheral wall portion 2A. The first cover 2B is a component independent of the peripheral wall portion 2A. The first end is an end of the first stator 4 that is close to the first yoke 40. The first yoke 40 is fixed to the first cover 2B. That is, the first cover 2B functions as a base portion 2Bb to which the first stator 4 is fixed. A portion of the first cover 2B in this example constitutes a first cover 5B of a pump housing 59, which will be described later. A flange is provided on the outer peripheral edge of the first cover 2B. The protruding height of the pump housing 59 is the same as or lower than the end face of the flange. Therefore, the protruding portion of the pump housing 59 is accommodated in a recessed space formed inside the flange of the first cover 2B.

[0038] The second cover 2C is an annular member that seals the second end of the peripheral wall 2A. The second end is the end opposite the first end. The second cover 2C may be a component independent of the peripheral wall 2A, or may be a component integral with the peripheral wall 2A. In this example, the second cover 2C, which is prepared separately from the peripheral wall 2A, is fitted onto the peripheral wall 2A, thereby integrating the peripheral wall 2A and the second cover 2C. The motor shaft 20 therefore passes through the second cover 2C. A bearing 25 is disposed between the second cover 2C and the motor shaft 20, and the motor shaft 20 is rotatably supported relative to the second cover 2C. A seal member that prevents fluid leakage from within the motor housing 29 may be disposed at the position of the bearing 25. Unlike this example, if the entire motor shaft 20 is disposed within the motor housing 29, the inner surface of the second cover 2C has a recess into which the end of the motor shaft 20 is fitted.

[0039] <First Pump> The first pump 5 will be described mainly with reference to Figures 4 to 6. Figure 4 is a diagram for explaining the arrangement of the first pump 5 in the pump assembly 1, with some components of the pump assembly 1 omitted or simplified. For example, Figure 4 omits the first cover 2B of the motor housing 29 and the motor rotor 3. Figure 4 also omits the first cover 5B (Figures 5 and 6) of the pump housing 59, which will be described later, and shows the interior of the first pump 5 exposed. In Figure 4, the first stator 4, the inlet port 51, and the outlet port 52 are indicated by two-dot chain lines.

[0040] The first pump 5 pumps a fluid. In this example, the fluid is a liquid. For example, the fluid is machine oil. The first pump 5 includes a first pump rotor 50 configured to be rotated by the motor rotor 3. The first pump 5 is disposed in a first internal space 21 surrounded by a plurality of first teeth 41.

[0041] The first pump 5 in this example is an internal gear pump having an external gear 55 and an internal gear 56. The external gear 55 is a disk-shaped gear with teeth on its outer periphery. The tooth profile of the external gear 55 is formed, for example, by a trochoid curve. The internal gear 56 is an annular gear with teeth on its inner periphery. The external gear 55 is disposed inside the internal gear 56, and the teeth of the external gear 55 mesh with the teeth of the internal gear 56. In this internal gear pump, the external gear 55 is the first pump rotor 50.

[0042] The external gear 55 and the internal gear 56 are disposed inside the pump housing 59. As shown in FIGS. 5 and 6, the pump housing 59 of this example is composed of a peripheral wall 5A, a first cover 5B, and a second cover 5C. The peripheral wall 5A is a cylindrical member. As shown in FIG. 4, the outer peripheral contour of the peripheral wall 5A, as viewed from the axis of the peripheral wall 5A, has a shape resembling a circle with a linear cut. A portion of a bolt hole 9h (described later) is formed in the peripheral wall 5A. The center of the arc of the outer peripheral contour is offset upward in FIG. 4 from the center of the motor housing 29 and coincides with the rotation center of the internal gear 56 (described later). By cutting the peripheral wall 5A, the pump housing 59 can be disposed in the first internal space 21 while ensuring the strength of the pump housing 59. Unlike this example, the center of the arc of the outer peripheral contour of the peripheral wall 5A does not have to coincide with the rotation center of the internal gear 56. Furthermore, the center of the arc of the outer peripheral contour of the peripheral wall portion 5A may or may not coincide with the rotation center of the external gear 55.

[0043] The inner peripheral contour of the peripheral wall 5A is circular when viewed from a direction along the axis of the peripheral wall 5A. The inner diameter of the peripheral wall 5A is slightly larger than the outer diameter of the internal gear 56. Therefore, the internal gear 56 can rotate with its outer peripheral surface in contact with the inner peripheral surface of the peripheral wall 5A. The rotation axis of the internal gear 56 is stabilized by being supported by the inner peripheral surface of the peripheral wall 5A.

[0044] As shown in FIG. 5 , the first cover 5B is a plate-shaped member that seals the first end of the peripheral wall portion 5A. In this example, the first cover 5B is a component independent of the peripheral wall portion 5A. Unlike this example, the first cover 5B may be a component integral with the peripheral wall portion 5A. Alternatively, the first cover 5B may be a component integral with the first cover 2B of the motor housing 29. In this example, the first cover 5B is fitted into a through-hole in an annular base portion 2Bb that constitutes part of the first cover 2B of the motor housing 29. In other words, the first cover 5B and the base portion 2Bb into which the first cover 5B is fitted constitute the first cover 2B of the motor housing 29. The first cover 5B has through-holes that form the inlet port 51 and the outlet port 52. A recess is formed on the inner surface of the first cover 5B. The end of the motor shaft 20 is rotatably fitted into the recess.

[0045] The second cover 5C is a plate-shaped member that seals the second end of the peripheral wall 5A. In this example, the second cover 5C is a component independent of the peripheral wall 5A. Unlike this example, the second cover 5C may be an integral component with the peripheral wall 5A. The second end is the end opposite the first end. A recess 5D is formed on the surface of the second cover 5C facing the first pump rotor 50. In this example, there are two recesses 5D. The two recesses 5D are positioned opposite each other across the motor shaft 20. When viewed from the direction along the axis of the motor shaft 20, each recess 5D has a generally arc-shaped shape. The shapes of the two recesses 5D may be different or the same. The recesses 5D reduce the sliding area between the external gear 55 and the second cover 5C and the sliding area between the internal gear 56 and the second cover 5C, thereby reducing torque loss in the first pump 5. The motor shaft 20 passes through the second cover 5C. A bearing 26 is disposed between the motor shaft 20 and a through hole through which the motor shaft 20 passes. Therefore, the motor shaft 20 is rotatably supported with respect to the second cover 5C. A seal member that prevents fluid from leaking from inside the pump housing 59 may be disposed at the position of the bearing 26.

[0046] As shown in Fig. 6, in this example, the peripheral wall portion 5A, the first cover 5B, and the second cover 5C are integrated with bolts 9. Bolt holes 9h in which the bolts 9 are arranged extend from the first cover 5B through the peripheral wall portion 5A to the second cover 5C. As shown in Fig. 4, there are three bolt holes 9h in this example. The three bolt holes 9h are arranged at equal intervals so as to surround the internal gear 56.

[0047] 6, bolts 9 connect the first cover 5B, the peripheral wall 5A, and the second cover 5C. In this example, the first cover 5B is integrated with the first cover 2B of the motor housing 29. Therefore, by connecting the first cover 5B, the peripheral wall 5A, and the second cover 5C with the bolts 9, the first end of the peripheral wall 2A of the motor housing 29 is sealed by the first cover 2B.

[0048] The bolt hole 9h in this example includes a small-diameter portion 95 in which the shank 90 of the bolt 9 is disposed, and a large-diameter portion 96 in which the head 91 of the bolt 9 is disposed. A thread is formed in at least a portion of the small-diameter portion 95 corresponding to the second cover 5C. A thread may also be formed in at least a portion of the small-diameter portion 95 corresponding to the peripheral wall portion 5A. The head 91 is secured to the step between the small-diameter portion 95 and the large-diameter portion 96. The head 91 is housed within the large-diameter portion 96 and does not protrude from the end face of the first cover 5B. Therefore, the head 91 does not increase the axial dimension of the pump assembly 1. As shown in FIGS. 1 and 2, a tool hole is formed in the end face of the head 91, into which a tool for rotating the bolt 9 is fitted. In this example, the tool hole has a hexagonal shape. The shape of the tool hole is not particularly limited.

[0049] As shown in Figure 4, the external gear 55 is fixed coaxially to the motor shaft 20. In other words, the rotation axis of the external gear 55 coincides with the rotation axis of the motor shaft 20. The rotation axis of the external gear 55 also coincides with the axis of the motor housing 29. The external gear 55 rotates in perfect synchronization with the rotation of the motor rotor 3. Therefore, the rotation speed of the external gear 55 can be controlled by controlling the rotation speed of the motor rotor 3. The flow rate of the fluid pumped by the first pump 5 changes depending on the rotation speed of the external gear 55.

[0050] The rotation axis of the internal gear 56, which is positioned by the peripheral wall portion 5A of the pump housing 59, is offset upward in the drawing from the rotation axis of the external gear 55. Therefore, the internal gear 56 rotates as the external gear 55 rotates, and the gap between the external gear 55 and the internal gear 56 moves in the rotation direction of the motor shaft 20. An inlet port 51 and an outlet port 52 open in the gap between the external gear 55 and the internal gear 56. Therefore, the fluid that flows into the gap from the inlet port 51 is transported in the rotation direction of the motor shaft 20 and is discharged from the first pump 5 through the outlet port 52.

[0051] The inlet port 51 and the outlet port 52 are disposed at positions approximately symmetrical with respect to the motor shaft 20. The inlet port 51 and the outlet port 52 are disposed in a first direction as viewed from the first pump rotor 50, i.e., the external gear 55. The first direction is a direction along the axis of the motor shaft 20 and a direction away from the motor rotor 3. In this example, the inlet port 51 and the outlet port 52 are formed in the first cover 5B, which is disposed further in the first direction than the first pump rotor 50. In this example, the inlet port 51 and the outlet port 52 extend in the first direction and open at the end surface of the first cover 5B. Unlike this example, the inlet port 51 and the outlet port 52 may be bent, for example, in an L-shape. In this case, the inlet port 51 and the outlet port 52 may open in a direction intersecting the first direction. Because the rotating motor rotor 3 is not present at the positions where the inlet port 51 and the outlet port 52 are disposed, the inlet port 51 and the outlet port 52 are easily disposed.

[0052] Unlike this example, the inlet port 51 and the outlet port 52 may extend radially. The radial direction is a direction perpendicular to the axis of the motor shaft 20 and away from the axis of the motor shaft 20. In this case, the inlet port 51 and the outlet port 52 each extend from between two adjacent first teeth 41 to the outside of the pump assembly 1.

[0053] In the pump assembly 1 of this example, the first pump 5 is disposed in the first internal space 21 of the motor 2. That is, the length of the pump assembly 1 of this example along the motor shaft 20 does not increase despite the inclusion of the first pump 5. Such a compact pump assembly 1 can be easily disposed in a narrow space such as the interior of an automobile.

[0054] The first pump 5 generates operating noise. The operating noise is, for example, the contact noise between the external gear 55 and the internal gear 56, and the pulsating noise generated when the fluid is pumped. The external gear 55 and the internal gear 56, which are the source of the operating noise, are enclosed in a pump housing 59. Moreover, the first pump 5 is disposed inside the motor 2. Therefore, in the pump assembly 1 of this example, the operating noise of the first pump 5 is unlikely to leak outside the pump assembly 1. Thus, the pump assembly 1 of this example is excellent in quietness.

[0055] The motor 2 generates heat during operation. The heat generated by the motor 2 easily increases the temperature of the first pump 5 disposed in the first internal space 21 of the motor 2. When the temperature of the first pump 5 increases, the temperature of the fluid in the first pump 5 increases and the viscosity of the fluid decreases. As a result, the load on the motor 2 is reduced and the power consumption of the motor 2 decreases. In particular, the load on the motor 2 is likely to be reduced early after the motor 2 is started when the temperature of the fluid is low. The first pump 5 disposed in the first internal space 21 has a high thermal capacity due to its structure. Therefore, the first pump 5 easily absorbs the heat generated by the motor 2 and can suppress the heat generation of the motor 2.

[0056] <Embodiment 2> The first pump 5 provided in the pump assembly 1 is not limited to an internal gear pump. For example, the first pump 5 may be an external gear pump, an impeller pump, a diaphragm pump, a vane pump, or a piston pump. In the second embodiment, a pump assembly 1 including a vane pump as the first pump 5 will be described with reference to FIG. 7. FIG. 7 can be viewed in the same way as FIG. 4.

[0057] The vane pump includes a first pump rotor 50 having multiple vanes 58. The vanes 58 are configured to move forward and backward, for example, using magnetic or centrifugal force. The inner circumferential surface of a pump housing 59 housing the first pump rotor 50 is generally elliptical when viewed along the axis of the motor shaft 20. Unlike the present example, the inner circumferential surface of the pump housing 59 may be circular. As the first pump rotor 50 rotates, the ends of the vanes 58 contact the inner circumferential surface of the pump housing 59, causing the vanes 58 to advance or retreat. Fluid contained in the space surrounded by the two adjacent vanes 58, 58, the inner circumferential surface of the pump housing 59, and the first pump rotor 50 is transported in the rotational direction of the first pump rotor 50 as the first pump rotor 50 rotates. Due to its excellent sealing performance, vane pumps can easily pump gas, liquid, or a mixture of gas and liquid.

[0058] The pump assembly 1 of this example has two inlet ports 51 and two outlet ports 52. The inlet ports 51 and the outlet ports 52 are arranged alternately around the axis of the motor shaft 20. There may be only one inlet port 51 and one outlet port 52.

[0059] <Embodiment 3> In the third embodiment, a pump assembly 1 including a single rotor / double stator type motor 2 will be described with reference to Fig. 8. Fig. 8 can be viewed in the same way as Fig. 5.

[0060] The motor 2 of this example further includes a second stator 6 that sandwiches the motor rotor 3 between itself and the first stator 4. The second stator 6 has the same configuration as the first stator 4. That is, the second stator 6 includes an annular second yoke 60, a plurality of second teeth 61, and a plurality of second coils 62. The second teeth 61 are disposed on a second surface 60s of the second yoke 60. The second surface 60s faces the first surface 40s of the first yoke 40. The end surfaces of the second teeth 61 have the same shape as the end surfaces of the first teeth 41 and face the end surfaces of the first teeth 41. That is, the first stator 4 and the second stator 6 are disposed symmetrically with respect to the motor rotor 3.

[0061] The motor rotor 3 of this example also has a plurality of magnets 31 on the surface facing the second stator 6. Unlike this example, the magnets 31 may be embedded in the base plate 30. In that case, one magnet 31 corresponds to both the first stator 4 and the second stator 6.

[0062] A single rotor, double stator motor 2 is typically more space efficient than a single rotor, single stator motor 2.

[0063] The motor 2 has a second internal space 22 surrounded by a plurality of second teeth 61. A second pump 7 is disposed in this second internal space 22. That is, the first pump 5 and the second pump 7 are disposed symmetrically with respect to the motor rotor 3. The second pump 7 is a pump independent of the first pump 5. The second pump 7 has the same configuration as the first pump 5. That is, the second pump 7 is an internal gear pump having an external gear 75 and an internal gear 76. The external gear 75 is a second pump rotor 70 configured to be rotated by the motor rotor 3. Specifically, the second pump rotor 70 is coaxially fixed to the motor shaft 20. That is, the motor shaft 20 also serves as the rotation axis of the first pump rotor 50 and the second pump rotor 70. The external gear 75 and the internal gear 76 are disposed inside a pump housing 79. Unlike this example, the first pump 5 and the second pump 7 may be pumps of a type other than internal gear pumps. Furthermore, the first pump 5 and the second pump 7 may be pumps of different types. For example, the first pump 5 may be an internal gear pump, and the second pump 7 may be a vane pump.

[0064] The inlet port 71 and the outlet port 72 extend along the axis of the motor shaft 20. The opening of the inlet port 71 and the opening of the outlet port 72 are located at positions away from the motor rotor 3. Because the rotating motor rotor 3 is not present in the positions where the inlet port 71 and the outlet port 72 are located, it is easy to arrange the inlet port 71 and the outlet port 72.

[0065] The peripheral wall portion 2A of the motor housing 29 has a size that can accommodate both the first pump 5 and the second pump 7. Therefore, the pump assembly 1 of this example is compact despite being equipped with two pumps.

[0066] The first cover 2B of the motor housing 29 in this example has the same configuration as the first cover 2B in embodiment 1. The second cover 2C of the motor housing 29 in this example has the same configuration as the first cover 2B. Therefore, a portion of the pump housing 79 penetrates the second cover 2C, but the pump housing 79 does not protrude from the end face of the second cover 2C. Unlike this example, the pump housing 79 may protrude from the end face of the first cover 2B, or the pump housing 79 may protrude from the end face of the second cover 2C.

[0067] The pump assembly 1 of this embodiment having the above-described configuration can pump fluids in two independent systems.

[0068] <Embodiment 4> In the fourth embodiment, a pump assembly 1 in which the configurations of the motor housing 29 and the pump housing 59 are different from those in the first embodiment will be described with reference to Fig. 9. In this example, the configurations other than the motor housing 29 and the pump housing 59 are the same as those in the first embodiment.

[0069] Fig. 9 is a cross-sectional view of the pump assembly 1 of this embodiment taken along the line VI-VI in Fig. 4. The position of the bolt 9 in this embodiment is different from that in the first embodiment.

[0070] The pump housing 59 of this example includes a body 8 and a pump cover 8C. The body 8 is a cylindrical component with a bottom, including a cylindrical portion 80, a bottom portion 81, and an annular flange portion 82. In Fig. 9, the boundary between the cylindrical portion 80 and the bottom portion 81, and the boundary between the cylindrical portion 80 and the annular flange portion 82 are indicated by two-dot chain lines.

[0071] The cylindrical portion 80 is a portion that covers the outer periphery of the internal gear 56. In other words, the cylindrical portion 80 corresponds to the peripheral wall portion 5A of the pump housing 59 in the first embodiment. The bottom portion 81 seals the first end face of the cylindrical portion 80 and is positioned facing the motor rotor 3. A through hole through which the motor shaft 20 passes is formed in the bottom portion 81. In other words, the bottom portion 81 corresponds to the second cover 5C of the pump housing 59 in the first embodiment. The annular flange portion 82 is a portion that extends outward from the vicinity of the second end face on the outer periphery of the cylindrical portion 80. The second end face is the end face opposite to the first end face. The outward direction of the cylindrical portion 80 is the direction away from the central axis of the cylindrical portion 80. The annular flange portion 82 has a generally annular shape. The first yoke 40 of the first stator 4 is fixed to the surface of the annular flange portion 82 that faces the motor rotor 3. That is, the annular flange portion 82 corresponds to the base portion 2Bb of the motor housing 29 in the first embodiment. The body 8 in which the cylindrical portion 80, the bottom portion 81, and the annular flange portion 82 are integrated is expected to contribute to reducing the number of assembly steps for the pump assembly 1 and to reducing the cost of the pump assembly 1 by reducing the number of parts.

[0072] The pump cover 8C seals an opening 80h that opens to the second end face of the tubular portion 80. The pump cover 8C corresponds to the first cover 5B of the pump housing 59 in the first embodiment. The outer diameter of the pump cover 8C is larger than the inner diameter of the opening 80h. The pump cover 8C and the annular flange portion 82 correspond to the first cover 2B of the motor housing 29 in the first embodiment.

[0073] The pump cover 8C is fixed to the annular flange portion 82 of the body 8 by bolts 9. Bolt holes 9h, into which the bolts 9 are disposed, penetrate the pump cover 8C and reach the annular flange portion 82. In other words, when viewed in a direction along the shaft portion 90 of the bolt 9, the shaft portion 90 does not overlap the tubular portion 80 of the body 8, and no bolt holes 9h for disposing the bolts 9 are formed in the tubular portion 80. The absence of the bolt holes 9h makes the tubular portion 80 thinner than the peripheral wall portion 5A in the first embodiment. The thinner tubular portion 80 allows the outer diameter of the tubular portion 80 to be smaller than that of the first embodiment. Reducing the outer diameter of the tubular portion 80 without changing the inner diameter of the tubular portion 80 compared to the first embodiment allows the outer diameter of the pump assembly 1 to be reduced without reducing the capacity of the first pump 5. The outer diameter of the pump assembly 1 refers to the dimension of the pump assembly 1 in a direction perpendicular to the axis of the motor shaft 20.

[0074] Since the cylindrical portion 80 is thinner, the inner diameter of the cylindrical portion 80 may be made smaller than in the configuration of embodiment 1. For example, by increasing the inner diameter of the cylindrical portion 80 without changing the outer diameter of the cylindrical portion 80 compared to the configuration of embodiment 1, the capacity of the first pump 5 can be increased without increasing the outer diameter of the pump assembly. Alternatively, the outer diameter of the cylindrical portion 80 may be made smaller and the inner diameter of the cylindrical portion 80 may be made larger compared to the configuration of embodiment 1.

[0075] In the configuration of this example in which the bolts 9 are connected to the annular flange portion 82, the bolts 9 do not interfere with the inlet port 51 and the outlet port 52. Therefore, there are fewer restrictions on the number and positions of the bolts 9 in this example than in the configuration of the first embodiment.

[0076] The configurations of the motor housing 29 and the pump housing 59 shown in the fourth embodiment can also be applied to the pump assembly 1 including the single rotor / double stator type motor 2 shown in the third embodiment. [Explanation of symbols]

[0077] 1 Pump Assembly 2 Axial gap motor, motor 20 motor shaft, 21 first internal space, 22 second internal space 25,26 Bearings 29 Motor housing 2A: Peripheral wall, 2B: First cover, 2C: Second cover 2Bb base 3 Motor rotor 30 base plate, 30s base surface 31 Magnet 4 First Stator 40 First York, 40s First Page 41 first teeth, 42 first coil 5 First Pump 50 First pump rotor 51 Inlet port, 52 Outlet port 55 external gear, 56 internal gear 58 Vane 59 Pump housing 5A: Peripheral wall portion, 5B: First cover, 5C: Second cover, 5D: Recess 6 Second Stator 60 second yoke, 60s second side 61 second teeth, 62 second coil 7 Second Pump 70 Second pump rotor 71 Inlet port, 72 Outlet port 75 External gear, 76 Internal gear 79 Pump housing 8. Body 80 cylindrical portion, 81 bottom portion, 82 annular flange portion, 80h opening 8C Pump Cover 9 volts 9h bolt hole 90 shaft, 91 head, 95 thin diameter part, 96 thick diameter part

Claims

1. an axial gap motor having a first stator, a motor rotor, and a motor shaft; a first pump having a first pump rotor configured to be rotated by the motor rotor; the first stator includes an annular first yoke and a plurality of first teeth arranged on a first surface of the first yoke; the first pump rotor is disposed in a first internal space surrounded by the plurality of first teeth; the first pump rotor is coaxially fixed to the motor shaft; Pump assembly.

2. the first pump having an inlet port and an outlet port; the inlet port and the outlet port are disposed in a first direction as viewed from the first pump rotor; The pump assembly of claim 1 , wherein the first direction is along the axis of the motor shaft and away from the motor rotor.

3. the first pump is an internal gear pump including an external gear and an internal gear, 3. The pump assembly of claim 1 or claim 2, wherein the external gear is the first pump rotor.

4. the axial gap motor includes a motor housing that houses the first stator and the motor rotor, the internal gear pump includes a pump housing that houses the external gear and the internal gear; the motor housing includes a base portion to which the first yoke is fixed, The pump housing includes: a body including a cylindrical portion that covers an outer periphery of the internal gear, a bottom portion that seals a first end face of the cylindrical portion, and an annular flange portion that extends outward from the cylindrical portion from a vicinity of a second end face of the cylindrical portion on the outer periphery of the cylindrical portion; a pump cover that seals an opening of the cylindrical portion at the second end surface; a bolt for fixing the pump cover to the annular flange portion, The pump assembly according to claim 3 , wherein the annular flange portion forms the seat portion.

5. the first pump is a vane pump, 3. The pump assembly of claim 1 or claim 2, wherein the first pump rotor has a plurality of vanes.

6. a second pump having a second pump rotor configured to be rotated by the motor rotor; the axial gap motor further includes a second stator sandwiching the motor rotor between the first stator and the second stator; the second stator includes an annular second yoke and a plurality of second teeth arranged on a second surface of the second yoke, The pump assembly according to claim 1 or 2, wherein the second pump is disposed in a second internal space surrounded by the plurality of second teeth.

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