Electrical pump and electrical pump unit

Abstract

An electrical pump (100, 200) comprises: a pump part (10) that discharges a fluid; a motor part (20) that drives the pump part (10); a control part (30) that rotates a drive shaft (1) and controls the motor part (20); and a housing (40, 140) that houses the pump part (10), the motor part (20), and the control part (30). The control part (30) has a substrate (32) on which an electronic component (31) is mounted. The housing (40) has a partition part (42) that provides a partition between the motor part (20) and the control part (30). The the partition part (42) has formed therein a cooling passage (48) through which the fluid is sucked into the pump part (10) passes.

Description

Electric pump and electric pump unit

[0001] The present invention relates to an electric pump and an electric pump unit.

[0002] JP2010-112302A discloses an electric pump unit in which a pump, an electric motor for driving the pump, and a motor controller are assembled in a unit housing. The controller has a board on which electronic components such as a capacitor are mounted, and is housed in the unit housing.

[0003] In an electric pump unit such as that described in JP2010-112302A, the electronic components of the controller generate heat during operation, and the heat is transferred to the unit housing. The unit housing is cooled by outside air, thereby cooling the controller (electronic components). In an electric pump unit such as that described in JP2010-112302A, because the controller is cooled by air in this manner, there is room for improvement in the cooling efficiency of the controller.

[0004] An object of the present invention is to improve the cooling efficiency of the control unit.

[0005] According to one aspect of the present invention, an electric pump comprises a pump section that discharges a fluid, a motor section that drives the pump section, a control section that controls the motor section by rotating a drive shaft, and a housing that accommodates the pump section, the motor section, and the control section, wherein the control section has a board on which electronic components are mounted, and the housing has a partition section that separates the motor section and the control section, and the partition section has a cooling passage formed therein through which the fluid sucked into the pump section passes.

[0006] FIG. 1 is a perspective view of an electric pump according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the electric pump according to the first embodiment of the present invention. FIG. 3 is a side view showing the electric pump according to the first embodiment of the present invention attached to a mounting body, the mounting body being shown in cross section. FIG. 4 is a schematic diagram showing the flow of fluid introduced into a suction port in the electric pump according to the first embodiment of the present invention, shown in correspondence with FIG. 1. FIG. 5 is a perspective view of an electric pump according to a second embodiment of the present invention. FIG. 6 is a side view of an electric pump unit according to the second embodiment of the present invention, showing the electric pump attached to a mounting body, the mounting body being shown in cross section. FIG. 7 is a schematic diagram showing the flow of fluid introduced into a suction port in the electric pump according to the second embodiment of the present invention, shown in correspondence with FIG. 5. FIG. 8 is a view showing an electric pump unit according to a second modification of the second embodiment of the present invention. FIG. 9 is a view showing an electric pump unit according to a fourth modification of the second embodiment of the present invention.

[0007] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0008] First Embodiment An electric pump 100 according to a first embodiment of the present invention will now be described with reference to the drawings. The electric pump 100 is mounted on, for example, a vehicle and discharges a coolant (fluid) for cooling an electric motor mounted on the vehicle, or discharges oil (fluid) for lubricating gears mounted on the vehicle. The electric pump 100 may also be used as a fluid pressure supply source that discharges a working fluid for driving equipment. The electric pump 100 may also be mounted on industrial machinery other than a vehicle.

[0009] FIG. 1 is a perspective view of electric pump 100, and FIG. 2 is a cross-sectional view of electric pump 100 as viewed from the front side in FIG. 1. As shown in FIGS. 1 and 2, electric pump 100 includes a pump unit 10 that discharges fluid, a motor unit 20 that rotates a drive shaft 1 to drive pump unit 10, a control unit 30 that controls motor unit 20, and a housing 40 that accommodates pump unit 10, motor unit 20, and control unit 30. In electric pump 100, the control unit 30, motor unit 20, and pump unit 10 are arranged in this order from the top in FIGS. 1 and 2. Hereinafter, the axial direction of drive shaft 1 will also be simply referred to as the "axial direction," and the radial direction of drive shaft 1 will also be simply referred to as the "radial direction."

[0010] In the first embodiment, the pump section 10 is a vane pump. As shown in Fig. 2, the pump section 10 has a pump rotor 11, vanes (not shown), a cam ring 12, a first side plate 13, and a second side plate 14. The configuration and operation of a vane pump are similar to those of a well-known configuration, and therefore detailed description thereof will be omitted. The pump section 10 is housed in a housing main body 41 and a pump cover 44 of a housing 40, which will be described later.

[0011] As shown in FIG. 1, the housing main body 41 has a suction port 45 that introduces fluid from the outside to the pump chamber 15 (see FIG. 2) of the pump section 10. Note that FIG. 2 shows a cross section that does not include the suction port 45. The pump cover section 44 is formed with a discharge port 46 that introduces fluid discharged from the pump chamber 15 to the outside. As the pump rotor 11 rotates, the pump chamber 15 expands in the suction region, where fluid is sucked in through the suction port 45. In the discharge region, where the pump chamber 15 contracts, fluid is discharged and introduced to the outside through the discharge port 46. In the first embodiment, two (a pair) suction ports 45 are provided facing each other across the drive shaft 1. That is, in FIG. 1, another suction port 45 is formed on the far side of the page.

[0012] 2, the motor section 20 has an annular stator 21 and a motor rotor 25 disposed radially inside the stator 21. The stator 21 and the motor rotor 25 are housed in a housing 40 (specifically, a housing main body 41).

[0013] The stator 21 includes an annular stator core 22 that surrounds the motor rotor 25 and a coil wire 23 wound around the stator core 22. The stator core 22 includes an annular yoke portion 22a that contacts the inner peripheral surface of the housing 40 (housing main body portion 41) and a plurality of teeth 22b that protrude radially inward from the yoke portion 22a and are arranged at predetermined intervals around the circumference. The coil wire 23 is wound around the teeth 22b of the stator core 22, thereby forming a U-phase coil, a V-phase coil, and a W-phase coil on each tooth 22b that correspond to the three-phase drive current. Ends of each coil wire 23 are connected to the control unit 30.

[0014] The motor rotor 25 has a rotor core 25a that is provided on the outer peripheral surface of the drive shaft 1 and rotates together with the drive shaft 1, and a plurality of permanent magnets 25b that are provided on the outer peripheral surface of the rotor core 25a. The permanent magnets 25b are provided in an annular shape, with north and south poles arranged alternately. In the motor section 20, the motor rotor 25 rotates around the drive shaft 1 as an axis due to the interaction between the magnetization state of the stator core 22 of the stator 21 and the permanent magnets 25b. This drives the pump section 10.

[0015] The control unit 30 controls the current supplied to the stator 21 to drive the motor unit 20. The control unit 30 has a substrate 32 on which electronic components 31 are mounted. The electronic components 31 include, for example, a magnetic detection sensor such as a Hall element that can detect changes in magnetism that occur in response to the rotation of the drive shaft 1, a calculation unit that calculates the rotation angle and rotation speed of the drive shaft 1 based on the detection value of the magnetic detection sensor, and transistors. The coil wires 23 of the motor unit 20 are electrically connected to the substrate 32. The control unit 30 controls the direction of the current flowing through the coil wires 23 of the stator 21 in accordance with the rotation angle of the drive shaft 1, and controls the magnitude of the current supplied to the coil wires 23 so that the rotation speed of the drive shaft 1 matches a target rotation speed input from outside. The control unit 30 is provided with the electronic components 31 in contact with the housing 40.

[0016] As shown in Figures 1 and 2, the housing 40 has a housing main body portion 41 having an opening 41a (see Figure 2), a partition portion 42 that covers the opening 41a and separates the motor portion 20 and the control portion 30, a cover portion 43 that is connected to the partition portion 42 and covers the control portion 30, and a pump cover portion 44 that houses and covers the pump portion 10.

[0017] As shown in FIG. 2 , the housing main body 41 has an insertion hole 41b through which the drive shaft 1 is inserted, an annular motor accommodating recess 41c that accommodates the motor unit 20, and a pump accommodating recess 41e that accommodates the pump unit 10. The insertion hole 41b extends axially from the opening 41a to the pump accommodating recess 41e and is formed radially inward of the motor accommodating recess 41c. The motor accommodating recess 41c is formed continuously with the opening 41a, and the annular yoke portion 22a of the stator core 22 of the motor unit 20 is provided in contact with the inner circumferential surface of the motor accommodating recess 41c. The insertion hole 41b accommodates a bearing 50 that is provided on the outer circumferential surface of the drive shaft 1 and rotatably supports the drive shaft 1, and an oil seal 60. The pump accommodating recess 41e accommodates the first side plate 13, a portion of the pump rotor 11, and a portion of the cam ring 12. The housing main body 41 is connected to the partition portion 42 by a fastening member 82 (see FIG. 1 ). As described above, a pair of suction ports 45 (see FIG. 1) are formed in the housing main body 41. In FIG. 1, only one of the suction ports 45 is shown, and another suction port 45 is formed on the far side of the page. The suction port 45 is formed across the pump cover 44.

[0018] The partition 42 is provided separately from the housing main body 41 and is connected to the housing main body 41 while covering the opening 41a of the housing main body 41. The partition 42 has a recessed accommodation portion 42a formed therein to accommodate the control unit 30. The accommodation portion 42a is formed at the end opposite the housing main body 41 and accommodates the electronic components 31 and the circuit board 32 of the control unit 30. The circuit board 32 is electrically connected to the outside via a connector (not shown) provided on the housing 40. The partition 42 is formed with a small diameter on the housing main body 41 side and a large diameter on the control unit 30 side, forming a shoulder surface 42d between the two.

[0019] A cooling passage 48 (see FIGS. 1 and 2) is formed in the partition 42. In FIG. 1, the opening area where the cooling passage 48 is formed is indicated by hatching. The cooling passage 48 is formed to be located between the electronic components 31 of the control unit 30 and the motor unit 20. The cooling passage 48 is formed to extend linearly and penetrate the partition 42. The cooling passage 48 is formed to cool the control unit 30, and its function will be described in detail below. An insertion hole 42c is formed in the partition 42, into which the end of the drive shaft 1 is inserted, and the insertion hole 42c accommodates a bearing 51 that is provided on the outer circumferential surface of the drive shaft 1 and rotatably supports the drive shaft 1.

[0020] The cover portion 43 has a protrusion 43a that protrudes from the opposite side (upward in FIG. 2 ) from the housing main body portion 41. The protrusion 43a is hollow and is provided to cover the circuit board 32 of the control portion 30. The cover portion 43 is fixed to the partition portion 42 by fastening members 81.

[0021] The pump cover 44 is provided to cover the pump accommodating recess 41e and is fixed to the housing main body 41 by fastening members 83 (see FIG. 1). The pump cover 44 is formed with a protrusion 44a that protrudes toward the side opposite the motor 20, and a discharge port 46 is formed in the protrusion 44a. An annular seal member 61 is provided on the outer peripheral surface of the protrusion 44a. As described above, the pump cover 44 is formed with a pair of suction ports 45 across the housing main body 41.

[0022] Next, the mounting and fluid flow of the electric pump 100 and the function of the cooling passage 48 will be described in detail.

[0023] Fig. 3 is a side view showing the electric pump 100 attached to the mounting body 101, and Fig. 4 is a schematic diagram showing the flow of fluid introduced into the suction port 45. In Fig. 3, the mounting body 101 is shown in cross section, and the opening 48b of the cooling passage 48 on the far side of the page, the suction port 45b on the far side of the page, and the flow of fluid on the far side of the page (arrows B and D) are shown by dotted lines. In Fig. 4, the inner peripheral surface of the mounting body 101 is also shown by dotted lines.

[0024] As shown in Figures 3 and 4, the electric pump 100 is mounted by being accommodated in a recessed accommodation portion 101a of the mounting base 101. The accommodation portion 101a is formed in a stepped shape having a large diameter portion 101b and a small diameter portion 101c. When the electric pump 100 is mounted to the mounting base 101, the shoulder surface 42d of the partition portion 42 contacts the end surface of the mounting base 101, and the tip of the protrusion 44a of the pump cover portion 44 is accommodated in the small diameter portion 101c. In addition, the housing main body 41, the portion of the partition portion 42 closer to the housing main body 41 than the shoulder surface 42d, and a part of the pump cover portion 44 are accommodated in the large diameter portion 101b. The large diameter portion 101b is formed with a diameter larger than the housing main body 41, the shoulder surface 42d of the partition 42, and the pump cover 44, and a space 70 is formed between the outer peripheral surface of the housing 40 and the inner peripheral surface of the large diameter portion 101b. The electric pump 100, the accommodating portion 101a, and the space 70 constitute an electric pump unit 105. The space 70 communicates with a supply passage 102 formed in the mounting body 101. The space 70 is supplied with fluid that is supplied to the electric pump 100 through the supply passage 102.

[0025] The fluid supplied from the supply passage 102 to the space 70 is guided to each of the two suction ports 45. Specifically, as indicated by arrow A in FIGS. 3 and 4 , the fluid is guided directly from the supply passage 102 to the suction port 45a, which is close to the supply passage 102. In contrast, the fluid is guided via two paths to the suction port 45b (see FIG. 3 ), which is far from the supply passage 102. Specifically, as indicated by arrow B in FIGS. 3 and 4 , the fluid is guided along the outer circumferential surface of the housing 40 to the suction port 45b located behind the suction port 45a. In addition, the fluid that has passed through the cooling passage 48 is also guided to the suction port 45b. More specifically, as indicated by arrow C in FIGS. 3 and 4 , the fluid supplied from the supply passage 102 is first guided to the cooling passage 48 through an opening 48a of the cooling passage 48, which is close to the supply passage 102. Because the cooling passage 48 is formed to extend linearly and penetrate the partition 42, the fluid that passes through the cooling passage 48 is guided to the opening 48b that is far from the supply passage 102, and is guided toward the back of the paper in Figures 3 and 4. The fluid that passes through the cooling passage 48 is then guided to the suction port 45b, as shown by arrow D in Figure 4. In this way, the fluid is guided from the supply passage 102 to the two suction ports 45.

[0026] In the electric pump 100 of the first embodiment, the electronic components 31 of the control unit 30 generate heat during operation. The electronic components 31 come into contact with the partition 42 of the housing 40, and the heat is transferred to the partition 42. Because the partition 42 is formed with a cooling passage 48, the partition 42 is cooled by the fluid passing through the cooling passage 48, thereby cooling the electronic components 31. In this way, by cooling the control unit 30 using the fluid drawn into the pump unit 10 rather than air cooling, the cooling efficiency of the control unit 30 can be improved.

[0027] In the first embodiment, the cooling passages 48 are formed in correspondence with the positions of the electronic components 31 on the substrate 32. Specifically, the cooling passages 48 are formed in positions that overlap the electronic components 31 in the axial direction. This allows cooling of positions close to the electronic components 31, which are heat sources, and allows the control unit 30 to be cooled more efficiently.

[0028] 2, in the first embodiment, the cooling passage 48 is formed such that the length D1 between the end of the partition 42 on the circuit board 32 side is longer than the length D2 between the end of the partition 42 on the motor unit 20 side. Specifically, the axial length D1 from the cooling passage 48 to the end of the partition 42 on the circuit board 32 side is longer than the axial length D2 from the cooling passage 48 to the end of the partition 42 on the motor unit 20 side. This allows for a larger thickness in the partition 42 from the cooling passage 48 to the end of the circuit board 32 side, which is the region through which heat from the electronic components 31 is transferred, thereby enabling more efficient cooling of the control unit 30. Furthermore, because the electric pump 100 is mounted with the shoulder surface 42d of the partition 42 in contact with the mounting base 101, stress is likely to act near the shoulder surface 42d when the electric pump 100 is mounted or when a load is applied to the electric pump 100. However, by forming the cooling passage 48 on the motor section 20 side of the partition section 42 in this manner and ensuring a sufficient thickness in the vicinity of the shoulder surface 42d, the strength of the partition section 42 can be improved.

[0029] Furthermore, in the first embodiment, the partition portion 42 is formed separately from the housing main body 41, and therefore the cooling passage 48 can be formed by processing the partition portion 42 alone. Therefore, the cooling passage 48 can be easily formed.

[0030] According to the first embodiment described above, the following effects are achieved.

[0031] In the electric pump 100, the partition 42 is formed with a cooling passage 48, and the partition 42 is cooled by the fluid passing through the cooling passage 48, thereby cooling the control unit 30. In this way, by using the fluid sucked into the pump unit 10 to cool the control unit 30, the cooling efficiency of the control unit 30 can be improved.

[0032] In the electric pump 100, the cooling passages 48 are formed in correspondence with the positions of the electronic components 31 on the substrate 32, so that the control unit 30 can be cooled more efficiently.

[0033] Next, modifications of the first embodiment will be described. The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the above embodiment, or to combine the configurations described in the following different modifications.

[0034] <First Modification of First Embodiment> In the first embodiment, the cooling passage 48 extends linearly and penetrates the partition 42, without surrounding the insertion hole 42c. However, the cooling passage 48 is not limited to the above configuration as long as it is formed in the partition 42 and allows the fluid to pass through it when it is drawn into the pump unit 10. For example, the cooling passage 48 may be formed so as to surround the insertion hole 42c and penetrate the partition 42 over a wide area of ​​the partition 42. Alternatively, multiple cooling passages 48 may be formed. Furthermore, it is not essential that the cooling passage 48 be formed to correspond to the position of the electronic components 31 of the control unit 30, or that the length between the end of the partition 42 on the circuit board 32 side is longer than the length between the end of the partition 42 on the motor unit 20 side.

[0035] <Second Modification of First Embodiment> In the first embodiment, the partition 42 is formed separately from the housing main body 41. However, the partition 42 may be formed integrally with the housing main body 41. Even with this configuration, the same effects as those of the first embodiment can be achieved.

[0036] <Third Modification of First Embodiment> In the first embodiment, the pump unit 10 is a vane pump. However, the pump unit 10 is not limited to this, and may be another type of pump such as a gear pump.

[0037] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Figures 5 to 9. The following description will focus on differences from the first embodiment, and the same components as those in the first embodiment will be denoted by the same reference numerals and will not be described again.

[0038] In the electric pump 100 of the first embodiment, the outer peripheral surface of the housing 40 is not provided with any structure that obstructs the flow of fluid in the space 70. In contrast, in the electric pump 200 of the second embodiment, an axial wall 49 that protrudes from the outer peripheral surface of the housing 140 is provided.

[0039] Specifically, as shown in FIGS. 5 and 6, the housing 140 has an axial wall 49 that protrudes from the outer circumferential surface of the housing 140.

[0040] The axial wall 49 protrudes radially from the outer circumferential surface of the housing 140. The axial wall 49 includes a first axial wall 49a and a second axial wall 49c extending in the axial direction. That is, in the second embodiment, a pair of axial walls 49 is provided. In the second embodiment, the first axial wall 49a and the second axial wall 49c are provided circumferentially spaced apart and facing each other with the drive shaft 1 in between. The first axial wall 49a and the second axial wall 49c are formed between the two suction ports 45 and between the two openings 48a, 48b of the cooling passage 48 in the circumferential direction of the drive shaft 1. The first axial wall 49a and the second axial wall 49c are formed from the shoulder surface 42d of the partition portion 42 to the outer circumferential surface of the housing main body portion 41 and the outer circumferential surface of the pump cover portion 44, respectively. The first axial wall 49a and the second axial wall 49c have top surfaces 49b, 49d that extend in the axial direction, and the top surfaces 49b, 49d are located between the inner circumferential edge and the outer circumferential edge of the shoulder surface 42d of the partition portion 42. In the second embodiment, the first axial wall 49a is located closer to a supply passage 102 (described later) than the second axial wall 49c. The first axial wall 49a and the second axial wall 49c are configured symmetrically with respect to the drive shaft 1, and therefore, hereinafter, the first axial wall 49a and the second axial wall 49c will also be collectively referred to simply as "axial walls 49."

[0041] As shown in Figure 6, when the electric pump 200 is attached to the mounting base 101, the tip ends of the axial walls 49 (first axial wall 49a and second axial wall 49c) contact a step portion 101d between the large diameter portion 101b and the small diameter portion 101c of the accommodation portion 101a. Furthermore, the housing main body 41, the portion of the partition portion 42 closer to the housing main body 41 than the shoulder surface 42d, a part of the pump cover portion 44, and the axial wall 49 are accommodated in the large diameter portion 101b. In Figure 6, the supply passage 102 communicates with the space 70 on the front side of the page relative to the first axial wall 49a.

[0042] The first axial wall 49a and the second axial wall 49c are provided to separate the space 70 into two. Specifically, the first axial wall 49a is provided such that a top surface 49b thereof contacts the inner circumferential surface of the large-diameter portion 101b of the accommodating portion 101a, and the second axial wall 49c is provided such that a top surface 49d thereof contacts the inner circumferential surface of the large-diameter portion 101b of the accommodating portion 101a. In other words, the first axial wall 49a and the second axial wall 49c are formed to correspond to the shape of the large-diameter portion 101b of the accommodating portion 101a so that the respective top surfaces 49b, 49d thereof contact the inner circumferential surface of the large-diameter portion 101b. This separates the space 70 into a first space 70a (the front side of the paper in FIG. 6 ) that communicates with the supply passage 102 and a second space 70b (the back side of the paper in FIG. 6 ) that does not communicate with the supply passage 102. A pair of axial walls 49 separate the two intake ports 45 and also separate the two openings 48 a and 48 b of the cooling passage 48 .

[0043] The fluid supplied from the supply passage 102 to the space 70 is guided to the two suction ports 45. Specifically, as indicated by arrow A in Figures 6 and 7 , the fluid is guided directly from the supply passage 102 to the first suction port 45a located in the first space 70a and close to the supply passage 102. In contrast, because the space 70 is separated by the axial wall 49, the fluid is not guided directly from the supply passage 102 to the second suction port 45b located in the second space 70b and far from the supply passage 102, but is instead guided to the second suction port 45b that has passed through the cooling passage 48. Specifically, as indicated by arrow B in Figures 6 and 7 , the fluid supplied from the supply passage 102 to the space 70a flows into the cooling passage 48 from the first opening 48a (inlet) of the cooling passage 48 that is close to the supply passage 102 (in the first space 70a). Because the cooling passage 48 is formed to extend linearly and penetrate the partition 42, the fluid that has passed through the cooling passage 48 flows out into the second space 70b from the second opening 48b (outlet) that is far from the supply passage 102 (located in the second space 70b), and is then guided to the second suction port 45b as shown by arrow C in Fig. 6. In this way, the fluid from the supply passage 102 is guided to the two suction ports 45 via two paths.

[0044] As described above, in the electric pump 200 of the second embodiment, the axial walls 49 (first axial wall 49a and second axial wall 49c) prevent the fluid from being directly guided from the supply passage 102 to the second suction port 45b, but guide the fluid that has passed through the cooling passage 48. That is, in this embodiment, the axial wall 49 separates the space 70 into two, and therefore the fluid is guided from one space 70a to the other space 70b through the cooling passage 48. Therefore, the flow rate guided to the cooling passage 48 increases, and the control unit 30 can be cooled efficiently.

[0045] In the second embodiment, the top surfaces 49b, 49d of the axial wall 49 are in contact with the inner circumferential surface of the large diameter portion 101b of the accommodation portion 101a, so that the axial wall 49 functions as a guide when the electric pump 200 is accommodated in the accommodation portion 101a. This makes it easy to attach the electric pump 200 to the attachment target 101.

[0046] According to the second embodiment described above, the following effects are achieved.

[0047] In the electric pump 200, the axial wall 49 obstructs the flow of fluid along the outer surface of the housing 140 and into the suction port 45 (second suction port 45b), increasing the flow rate into the cooling passage 48, thereby enabling the control unit 30 to be cooled efficiently.

[0048] Next, modifications of the second embodiment will be described. The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the above embodiment, or to combine the configurations described in the following different modifications.

[0049] <First Modification of Second Embodiment> In the second embodiment, a pair of axial walls 49 (first axial wall 49a and second axial wall 49c) are provided to separate the space 70 into two. However, this is not limited to this, and only one of the first axial wall 49a and the second axial wall 49c may be provided. In this case, the axial wall 49 is formed in the circumferential direction between the two suction ports 45 and between the two openings 48a, 48b of the cooling passage 48. In this case, since the space 70 is not separated into two, the fluid that has passed through the cooling passage 48 is guided to the second suction port 45b that is far from the supply passage 102, and the fluid that flows from the supply passage 102 along the outer circumferential surface of the housing 140 is also guided thereto. However, even in this modification, the axial wall 49 obstructs the flow of the fluid that flows along the outer circumferential surface of the housing 140 and is guided to the second suction port 45b, increasing the flow rate guided to the cooling passage 48, thereby enabling efficient cooling of the control unit 30.

[0050] <Second Modification of the Second Embodiment> As shown in FIG. 8 , in addition to the axial wall 49, the housing 140 may further include a circumferential wall 49e formed on the outer peripheral surface of the housing main body 41 and extending in the circumferential direction. The circumferential wall 49e is formed between the supply passage 102 and the first suction port 45a close to the supply passage 102, with one end formed in contact with the first axial wall 49a. A top surface 49f of the circumferential wall 49e is provided in contact with the inner peripheral surface of the large diameter portion 101b of the accommodating portion 101a. In this case, a raised portion 45c is formed around the first suction port 45a, and the distance between the raised portion 45c and the inner peripheral surface of the large diameter portion 101b is small. In this configuration, the circumferential wall 49e diverts and provides resistance to the flow of fluid from the supply passage 102 to the first suction port 45a, as indicated by arrow D. Therefore, the flow rate guided to the first suction port 45a close to the supply passage 102 is reduced, and a larger flow rate can be guided to the cooling passage 48 and the second suction port 45b far from the supply passage 102. This makes it possible to efficiently cool the control unit 30. Note that a configuration may also be adopted in which the circumferential wall 49e is formed between the first axial wall 49a and the second axial wall 49c, and the fluid is guided from the supply passage 102 to the first suction port 45a through a notch formed in the circumferential wall 49e.

[0051] In the second embodiment, the axial wall 49 is provided in contact with the inner circumferential surface of the large diameter portion 101b of the accommodation portion 101a and the step portion 101d. However, the axial wall 49 does not necessarily have to be in contact with the inner circumferential surface of the large diameter portion 101b of the accommodation portion 101a and the step portion 101d, and may be provided with a gap therebetween.

[0052] <Fourth Modification of the Second Embodiment> As shown in FIG. 9 , a flow rate adjusting portion may be formed in the axial wall 49. Specifically, a notch 49g may be formed in the axial wall 49 as the flow rate adjusting portion, and the fluid may be guided to the second suction port 45b, which is far from the supply passage 102, through the notch 49g. In this configuration, the fluid is guided to the second suction port 45b not only through the cooling passage 48 but also through the notch 49g. Therefore, by adjusting the shape (size) of the notch 49g, the flow rate guided to the second suction port 45b can be controlled. This prevents malfunctions of the electric pump 200 due to a low flow rate guided to the second suction port 45b. Note that the flow rate adjusting portion is not limited to the notch 49g, and may be a through-hole formed through the axial wall 49 or a gap formed between the axial wall 49 and the accommodation portion 101a as in the third modification.

[0053] <Fifth Modification of the Second Embodiment> In the second embodiment, the pump unit 10 is a vane pump. However, the pump unit 10 may be another type of pump, such as a gear pump. In this case, the housing 140 has one suction port 45, and the two openings 48a, 48b of the cooling passage 48 are separated by a pair of axial walls 49. Even in this configuration, the axial wall 49 separates the space 70 into two, and fluid is guided from one space 70 to the other space 70 through the cooling passage 48. This increases the flow rate guided to the cooling passage 48, thereby enabling efficient cooling of the control unit 30. In this case, the suction port 45 is preferably provided in the second space 70b that does not communicate with the supply passage 102, so as to increase the flow rate guided to the cooling passage 48. Furthermore, even when only one of the first axial wall 49a and the second axial wall 49c is provided as in the above-described first modification, the axial wall 49 obstructs the flow of the fluid that flows along the outer circumferential surface of the housing 140 and is led to the suction port 45, increasing the flow rate led to the cooling passage 48, thereby efficiently cooling the control unit 30. In this case, it is preferable that the suction port 45 be provided at a position away from the supply passage 102 so that the flow rate led to the cooling passage 48 is increased.

[0054] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0055] The electric pumps 100, 200 comprise a pump section 10 that discharges fluid, a motor section 20 that drives the pump section 10, a control section 30 that controls the motor section 20 by rotating a drive shaft 1, and a housing 40, 140 that accommodates the pump section 10, the motor section 20, and the control section 30. The control section 30 has a board 32 on which electronic components 31 are mounted. The housings 40, 140 have a partition section 42 that separates the motor section 20 and the control section 30. The partition section 42 has a cooling passage 48 formed therein through which the fluid sucked into the pump section 10 passes.

[0056] In this configuration, heat generated by the electronic components 31 of the control unit 30 when the electric pumps 100, 200 are driven is transferred to the partition 42. Because the partition 42 has a cooling passage 48 formed therein, the partition 42 is cooled by the fluid passing through the cooling passage 48, thereby cooling the control unit 30. In this way, by using the fluid drawn into the pump unit 10 to cool the control unit 30, the cooling efficiency of the control unit 30 can be improved.

[0057] In the electric pumps 100 and 200 , the cooling passages 48 are formed in correspondence with the positions of the electronic components 31 on the substrate 32 .

[0058] In this configuration, the control unit 30 can be cooled more efficiently by utilizing the fluid sucked into the pump unit 10.

[0059] In the electric pumps 100 and 200, the cooling passage 48 is formed so that the length between the end of the partition portion 42 on the substrate 32 side is longer than the length between the end of the partition portion 42 on the motor portion 20 side.

[0060] In this configuration, the control unit 30 can be cooled more efficiently by utilizing the fluid sucked into the pump unit 10.

[0061] In addition, in the electric pumps 100 and 200, the housing 140 further has a housing main body 41 in which the motor section 20 is accommodated, the partition section 42 is provided separately from the housing main body 41 and connected to the housing main body 41, and the control section 30 is provided at the end of the partition section 42 opposite the housing main body 41.

[0062] In this configuration, the cooling passage 48 can be easily formed by processing the partition portion 42 provided separately from the housing main body portion 41.

[0063] The electric pump unit 105 also comprises an electric pump 200, a mounting body 101 having an accommodation section 101a in which the electric pump 200 is accommodated, and a space 70 formed between the electric pump 200 and the accommodation section 101a through which a fluid flows, and the housing 140 of the electric pump 200 further has an intake port 45 that directs the fluid in the space 70 to the pump section 10, and an axial wall 49 that protrudes from the outer peripheral surface of the housing 140 and extends in the axial direction of the drive shaft 1, and the partition section 42 of the housing 140 further has two openings 48a, 48b which are the inlet and outlet of the cooling passage 48, and the axial wall 49 is formed between the two openings 48a, 48b of the cooling passage 48 in the circumferential direction of the drive shaft 1.

[0064] In this configuration, the axial wall 49 obstructs the flow of fluid along the outer surface of the housing 140 and into the intake port 45, increasing the flow rate into the cooling passage 48, thereby enabling the control unit 30 to be cooled efficiently.

[0065] In addition, in the electric pump unit 105, a pair of axial walls 49 are provided circumferentially spaced apart to separate the space 70 into two, and the pair of axial walls 49 separate the two openings 48a, 48b of the cooling passage 48.

[0066] In this configuration, the space 70 is separated into two by the axial wall 49, and the fluid is guided from one space 70 to the other space 70 through the cooling passage 48. Therefore, the flow rate guided to the cooling passage 48 is increased, and the control unit 30 can be cooled efficiently.

[0067] In addition, in the electric pump unit 105, the housing 40 has two suction ports 45, and the mounting body 101 is formed with a supply passage 102 that communicates with the space 70 and supplies fluid to the space 70, and the axial wall 49 further has a circumferential wall 49e that is formed between the supply passage 102 and the suction port 45 close to the supply passage 102 and extends circumferentially of the drive shaft 1, and the circumferential wall 49e provides resistance to the flow of fluid from the supply passage 102 to the suction port 45a close to the supply passage 102.

[0068] In this configuration, resistance is applied to the fluid guided to the suction port 45a close to the supply passage 102, thereby increasing the flow rate guided to the cooling passage 48 and the suction port 45b far from the supply passage 102, thereby enabling the control unit 30 to be cooled efficiently.

[0069] In addition, in the electric pump unit 105, the housing 140 has two suction ports 45, and the mounting body 101 has a supply passage 102 formed therein that is connected to the space 70 and supplies fluid to the space 70, and a flow rate adjustment portion (notch 49g) is formed in the axial wall 49 or between the axial wall 49 and the accommodating portion 101a, and the fluid is guided through the flow rate adjustment portion to the suction port 45b that is far from the supply passage 102.

[0070] In this configuration, the fluid is guided to the suction port 45b not only through the cooling passage 48 but also through the flow rate adjusting portion, so that the flow rate guided to the suction port 45b can be controlled by adjusting the shape of the flow rate adjusting portion.

[0071] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0072] This application claims priority based on Japanese Patent Application No. 2023-142141 filed with the Japan Patent Office on September 1, 2023, and Japanese Patent Application No. 2023-142142 filed with the Japan Patent Office on September 1, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. An electric pump comprising: a pump section that discharges fluid; a motor section that drives the pump section; a control section that controls the motor section by rotating a drive shaft; and a housing that accommodates the pump section, the motor section, and the control section, wherein the control section has a board on which electronic components are mounted, and the housing has a partition section that separates the motor section and the control section, and the partition section has a cooling passage formed therein through which fluid sucked into the pump section passes.

2. An electric pump according to claim 1, wherein the cooling passage is formed in correspondence with the position of the electronic component on the board.

3. An electric pump as claimed in claim 2, wherein the cooling passage is formed so that the length between the partition part and the end of the partition part on the substrate side is longer than the length between the partition part and the end of the partition part on the motor part side.

4. An electric pump as described in claim 1, wherein the housing further has a housing main body portion in which the motor portion is accommodated, the partition portion is provided separately from the housing main body portion and connected to the housing main body portion, and the control portion is provided at the end of the partition portion opposite the housing main body portion.

5. An electric pump unit comprising: an electric pump as defined in any one of claims 1 to 4; a mounting body having an accommodation portion in which the electric pump is accommodated; and a space formed between the electric pump and the accommodation portion through which a fluid flows, wherein the housing of the electric pump further has an intake port for directing fluid in the space to the pump portion, and an axial wall protruding from the outer circumferential surface of the housing and extending in the axial direction of the drive shaft, wherein the partition portion of the housing further has two openings which are an inlet and an outlet of the cooling passage, and the axial wall is formed between the two openings of the cooling passage in the circumferential direction of the drive shaft.

6. An electric pump unit as claimed in claim 5, wherein the axial walls are provided as a pair spaced apart in the circumferential direction to separate the space into two, and the pair of axial walls separate the two openings of the cooling passage.

7. An electric pump unit as described in claim 5, wherein the housing has two of the suction ports, the mounting body is formed with a supply passage communicating with the space and supplying fluid to the space, the housing further has a circumferential wall formed between the supply passage and the suction port close to the supply passage and extending in the circumferential direction of the drive shaft, and the circumferential wall provides resistance to the flow of fluid from the supply passage to the suction port close to the supply passage.

8. An electric pump unit as described in claim 5, wherein the housing has two of the suction ports, a supply passage is formed in the mounting body which communicates with the space and supplies fluid to the space, a flow rate adjustment section is formed in the axial wall or between the axial wall and the accommodating section, and fluid is guided through the flow rate adjustment section to the suction port which is far from the supply passage.

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