Electric pump

Abstract

To reduce pressure loss in electric pumps. [Solution] The housing 20 of the electric pump 100 has a main body 30 and a cover 40. Inside the cylindrical portion 45 of the cover 40, a first port, which is one of the suction port 51 and the discharge port 52, is formed. A second port, which is the other of the suction port 51 and the discharge port 52, is formed in the flange portion 41 of the cover 40. The cover 40 further has a first opening 53 facing one axial end of the pump chamber 13 and a radial passage 54 connecting the first opening 53 and the second port. On the bottom surface 31a of the recess 31 of the main body 30, a second opening 33 facing the other axial end of the pump chamber 13 is formed, axially aligned with the first opening 53 across the pump chamber 13. The pump 10 or the main body 30 has an axial passage 37 that connects the second opening 33 and the second port and extends axially in the pump chamber 13.

Description

[[Technical Field]]

[0001] The present invention relates to an electric pump. [[Background Art]]

[0002] Patent Document 1 discloses an electric pump (internal gear pump) in which a pump unit is housed in a housing. The pump unit has a shaft, a pinion gear connected to the shaft, and a ring gear meshing with the pinion gear. A suction port and a discharge port opening to the outer surface of the housing are formed in the housing, and liquid is supplied and discharged through a communication passage that connects the suction port to the pump chamber and a communication passage that connects the discharge port to the pump chamber. [[Prior Art Documents]] [[Patent Documents]]

[0003] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2023-183867 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0004] In the electric pump described in Patent Document 1, the suction-side and discharge-side communication passages that communicate with the pump chamber are each formed in an L-shape. As a result, pressure loss in the communication passages is large. On the other hand, it is also conceivable to form the communication passages so as to extend linearly from the pump chamber, but there are cases where it is difficult to form the communication passages linearly due to structural constraints of the electric pump.

[0005] The present invention has been made in view of the above problems, and an object of the present invention is to reduce pressure loss in an electric pump. [[Means for Solving the Problem]]

[0006] The present invention relates to an electric pump comprising a motor unit for driving a drive shaft, a pump unit connected to the drive shaft for discharging liquid, and a housing for housing the motor unit and the pump unit. The housing has a main body portion with a recess for housing the pump unit, and a cover portion attached to the main body portion and sealing the recess. The cover portion has an annular flange portion attached to the main body portion, a cylindrical portion formed projecting axially from the flange portion, a suction port for guiding liquid to the pump unit, and a discharge port for guiding liquid discharged from the pump unit. Inside the cylindrical portion are the suction port and the discharge port. A first port is formed on one side, and a second port, which is the other of the suction port and discharge port, is formed in the flange portion offset from the pump portion, and the cover portion further has a first opening facing one axial end of the pump chamber of the pump portion, and a radial passage connecting the first opening and the second port and extending radially in the pump chamber, and a second opening facing the other axial end of the pump chamber is formed on the bottom surface of the recess, aligned axially with the first opening on either side of the pump chamber, and the pump portion or main body portion has an axial passage connecting the second opening and the second port and extending radially in the pump chamber.

[0007] In this invention, a second port formed in the flange communicates with the pump chamber of the pump section through radial and axial passages. In other words, since multiple passages are provided that connect the second port to the pump chamber, the overall cross-sectional area of ​​the passages can be increased. This reduces pressure loss.

[0008] The present invention is characterized in that a suction port is formed as a first port on the inside of the cylindrical portion, and a discharge port is formed as a second port on the flange portion.

[0009] This invention makes it possible to reduce pressure loss on the discharge side of an electric pump.

[0010] The present invention relates to a pump section comprising an inner rotor having a plurality of external teeth and connected to a drive shaft, and an outer rotor having a plurality of internal teeth that slide in contact with the external teeth and positioned outside the inner rotor, wherein the axial passage is formed on the inner circumferential surface of a recess in the housing, and the cross section perpendicular to the drive shaft extends radially in the pump section.

[0011] The present invention is characterized in that the axial passage is formed in a rectangular shape with a cross-section perpendicular to the drive shaft and elongated in the radial direction of the pump section.

[0012] In these inventions, in a configuration where the pump section is an internal gear pump, it is possible to prevent the rotating outer rotor from getting caught in the axial passage.

[0013] The present invention is characterized in that the pump section comprises a rotor connected to a drive shaft and driven to rotation, a plurality of vanes slidably housed in a plurality of slits opening on the outer circumferential surface of the rotor, and a cam ring having an inner circumferential cam surface with which the tips of the vanes slide against as the rotor rotates, and the axial passage is formed on the outer circumferential surface of the cam ring.

[0014] In this invention, in a configuration where the pump section is a vane pump, an axial passage can be easily formed. [Effects of the Invention]

[0015] According to the present invention, pressure loss can be reduced in an electric pump. [Brief explanation of the drawing]

[0016] [Figure 1] This is a perspective view of an electric pump according to an embodiment of the present invention. [Figure 2] This is a perspective view of the pump section of an electric pump according to an embodiment of the present invention. [Figure 3] This is a perspective view of the pump section of an electric pump according to an embodiment of the present invention, showing the state with the cover removed. [Figure 4]It is a perspective view showing the main body portion of a housing, showing a state where the pump portion is removed. [Figure 5] It is a partial cross-sectional view of an electric pump according to an embodiment of the present invention. [Figure 6] It is a side view of the electric pump and the mounted body according to an embodiment of the present invention, wherein the mounted body is shown in a cross-sectional view. [Figure 7] It is a plan view of a pump portion of an electric pump according to Modification 2 of the embodiment of the present invention. [Figure 8] It is a perspective view of a pump portion of an electric pump according to Modification 3 of the embodiment of the present invention. [Figure 9] It is a partial cross-sectional view of an electric pump according to Modification 3 of the embodiment of the present invention. MODE FOR CARRYING OUT THE INVENTION

[0017] Hereinafter, an electric pump 100 according to an embodiment of the present invention will be described with reference to the drawings. The electric pump 100 is mounted, for example, on a vehicle, and discharges a cooling liquid (liquid) for cooling equipment mounted on the vehicle, or discharges oil (liquid) for lubricating gears mounted on the vehicle. The electric pump 100 may be used as a fluid pressure supply source that discharges a working fluid (liquid) for driving equipment. Further, the electric pump 100 may be mounted on industrial machinery other than vehicles.

[0018] FIG. 1 is a perspective view of the electric pump 100, and FIG. 2 is a perspective view of a pump portion 10 of the electric pump 100. FIG. 3 is a perspective view of the pump portion 10 showing a state where the cover portion 40 is removed, and FIG. 4 is a perspective view showing a state where the pump portion 10 is removed from the state of FIG. 3.

[0019] As shown in FIGS. 1 to 3, the electric pump 100 includes: a motor unit 15 (see FIG. 1) that drives a drive shaft 1 (see FIG. 3); a pump unit 10 (see FIGS. 1 and 2) that is connected to the drive shaft 1 and discharges liquid; a control unit 17 (see FIG. 1) that controls the motor unit 15; and a housing 20 (see FIGS. 1 and 2) that houses the motor unit 15, the pump unit 10, and the control unit 17. The arrow in FIG. 3 indicates the rotation direction of the drive shaft 1.

[0020] The motor unit 15 includes an annular stator (not shown) and a motor rotor (not shown) disposed radially inward of the stator. The motor rotor rotates about the drive shaft 1 by the action between the magnetization state of the stator core and the permanent magnet (not shown) of the motor rotor. A known configuration can be employed for the configuration of the motor unit 15, so a detailed description thereof is omitted.

[0021] In the present embodiment, the pump unit 10 is configured as an internal gear pump. Specifically, as shown in FIG. 3, the pump unit 10 includes an inner rotor 11 to which the drive shaft 1 is connected, and an outer rotor 12 disposed outside the inner rotor 11. The inner rotor 11 and the outer rotor 12 are housed in the housing 20 (specifically, a main body portion 30 described later), are provided eccentric to each other, and are covered by a cover portion 40 of the housing 20. Specifically, the center of the inner rotor 11 is provided to coincide with the center of the drive shaft 1, and the center of the outer rotor 12 is provided to be radially offset from the drive shaft 1. The inner rotor 11 has a plurality of external teeth 11a on its outer peripheral surface, and the outer rotor 12 has a plurality of internal teeth 12a in sliding contact with the external teeth 11a on its inner peripheral surface. The external teeth 11a and the internal teeth 12a are formed to have different numbers of teeth, and pump chambers 13 are defined by adjacent external teeth 11a of the inner rotor 11 and the internal teeth 12a of the outer rotor 12. A plurality of said pump chambers 13 are formed in the pump unit 10.

[0022] The control unit 17 controls the current supplied to the stator in order to drive the motor unit 15, and includes a circuit board (not shown) and electronic components such as magnetic sensors (not shown) mounted on the circuit board. Since a known configuration can be used for the control unit 17, a detailed explanation is omitted.

[0023] When the drive shaft 1 is rotated by the motor unit 15, the inner rotor 11 and outer rotor 12 rotate as the outer teeth 11a of the inner rotor 11 slide against the inner teeth 12a of the outer rotor 12. As the inner rotor 11 and outer rotor 12 rotate, the volume of the pump chamber 13 repeatedly expands and contracts. In the expanded region (suction region) where the pump chamber 13 expands, liquid is drawn in through the suction port 51 of the housing 20, which will be described later. In the contracted region (discharge region) where the pump chamber 13 contracts, liquid is discharged and led to the outside through the discharge port 52 of the housing 20, which will be described later.

[0024] As shown in Figures 1 to 3, the housing 20 has a main body 30 that houses the pump unit 10, the motor unit 15, and the control unit 17, and a cover unit 40 (see Figures 1 and 2) that is attached to the main body 30 and covers the pump unit 10. The main body 30 and the cover unit 40 are arranged side by side in the axial direction of the drive shaft 1. A pair of mounting flanges 35 (see Figures 1 and 6) for attaching the electric pump 100 to the mounting body 101, as will be described later, are formed on the outer circumferential surface of the main body 30. The mounting flanges 35 have through holes 36 (see Figure 1) through which fixing members 70 (see Figure 6), such as bolts, are inserted.

[0025] First, the cover portion 40 will be described. As shown in Figure 2, the cover portion 40 is provided so as to cover the recess 31 (see Figures 3 and 4) of the main body portion 30 in which the inner rotor 11 and outer rotor 12 are housed. The cover portion 40 is attached to the end face 30a (see Figures 3 and 4) of the main body portion 30 by fastening members 50. The cover portion 40 has an annular flange portion 41 attached to the end face 30a, a cylindrical portion 45 formed projecting axially from the flange portion 41, a suction port 51 for guiding liquid from the outside to the pump chamber 13 of the pump portion 10, and a discharge port 52 for guiding liquid discharged from the pump chamber 13 to the outside. The axial direction of the flange portion 41 is the same as the axial direction of the drive shaft 1, and hereafter, the axial direction of both will simply be referred to as the "axial direction".

[0026] The flange portion 41 is formed to have the same outer diameter as the main body portion 30 of the housing 20. A cylindrical portion 45 is continuously formed on the flange portion 41. A discharge port 52 is formed on the flange portion 41, extending circumferentially and penetrating axially. In addition, multiple fastening holes (not shown) are formed on the flange portion 41 for fastening fastening members 50.

[0027] The cylindrical portion 45 is formed concentrically with the flange portion 41. In an axial view, the inner region of the cylindrical portion 45 projectively overlaps with both the suction region where the pump chamber 13 expands and the discharge region where the pump chamber 13 contracts. Inside the cylindrical portion 45, a suction port 51 is formed corresponding to the suction region, and a partition portion 46 is formed separating the suction port 51 from the discharge region. An annular sealing member 60, such as an O-ring, is provided on the outer circumferential surface of the tip of the cylindrical portion 45.

[0028] As shown in the cross-sectional view of the area around the pump section 10 in Figure 5, the suction port 51 is formed opposite the pump chamber 13a so as to communicate with the pump chamber 13a in the suction region. The partition 46 is formed between the suction port 51 and the pump chamber 13b so that the inside of the cylindrical section 45 does not communicate with the pump chamber 13b in the discharge region. As a result, the inside of the cylindrical section 45 becomes a suction space that communicates with the pump chamber 13a.

[0029] As shown in Figure 5, the discharge port 52 is offset from the pump section 10 (specifically, the pump chamber 13b in the discharge region) (in this embodiment, offset radially outward) and is formed facing the end face 30a of the main body section 30. In relation to the discharge port 52, the cover section 40 has a first opening 53 facing one axial end side (upper side in Figure 5) of the pump chamber 13b, and a radial passage 54 that connects the first opening 53 and the discharge port 52 and extends radially in the direction of the pump chamber 13b.

[0030] The first opening 53 is formed in an arc shape along the circumferential direction of the drive shaft 1 in the discharge region of the pump section 10. A portion of the liquid discharged from the pump chamber 13b is guided into the first opening 53. Details of the liquid flow discharged from the pump chamber 13b will be described later. A portion of the first opening 53 faces one axial end (upper side in Figure 5) of the outer rotor 12 of the pump section 10. The radial passage 54 is formed together with the first opening 53 and the discharge port 52, opening at the end face (lower end face in Figure 5) of the cover section 40. One end of the radial passage 54 communicates with the first opening 53, and the other end communicates with the discharge port 52. As a result, the discharge port 52 communicates with the pump chamber 13b in the discharge region through the radial passage 54 and the first opening 53, and discharges liquid. The radial passage 54 is formed with a smaller flow path cross-sectional area than the first opening 53.

[0031] Next, the main body portion 30 will be described. As shown in Figures 3 and 4, the main body portion 30 has an insertion hole 34 (see Figure 4) through which the drive shaft 1 is inserted, and a recess 31 for housing the pump portion 10. Multiple fastening holes 30b are formed on the end face 30a of the main body portion 30, corresponding to the fastening holes of the flange portion 41, through which fastening members 50 (see Figure 2), such as bolts for attaching the cover portion 40, are fastened.

[0032] The recess 31 is a space with a circular bottom surface 31a (see Figure 4), and the inner rotor 11 and outer rotor 12 of the pump unit 10 are housed eccentrically within it. Specifically, the center of the recess 31 coincides with the center of the outer rotor 12 and is offset from the center of the drive shaft 1. As shown in Figure 4, the bottom surface 31a of the recess 31 has a suction-side opening 32 formed in the suction region of the pump unit 10 and a second opening 33 formed in the discharge region.

[0033] The suction-side opening 32 and the second opening 33 are formed in an arc shape along the circumferential direction of the drive shaft 1 and are formed in a groove shape on the bottom surface 31a. The suction-side opening 32 and the second opening 33 are formed in a symmetrical shape to each other. The suction-side opening 32 is formed opposite the pump chamber 13a so as to communicate with the pump chamber 13a in the suction region. The suction-side opening 32 is formed axially aligned with the suction port 51, with the pump chamber 13a in between (see Figure 5). The second opening 33 is formed opposite the pump chamber 13b so as to communicate with the pump chamber 13b in the discharge region. The second opening 33 is formed axially aligned with the first opening 53 of the cover portion 40, with the pump chamber 13b in between (see Figure 5). In other words, in the discharge region, one axial end of the pump chamber 13b (upper side in Figure 5) faces the first opening 53, and the other axial end (lower side in Figure 5) faces the second opening 33. Therefore, the liquid discharged from the pump chamber 13b is guided to the first opening 53 and the second opening 33, respectively. Part of the second opening 33 faces the other axial end (lower side in Figure 5) of the outer rotor 12 of the pump section 10. As a result, the pressure of the liquid in the first opening 53 and the pressure of the liquid in the second opening 33 act on the outer rotor 12 in opposite directions. Therefore, the outer rotor 12 is prevented from being pushed by only one of the main body 30 and the cover 40, and the frictional force between the outer rotor 12 and the main body 30 and cover 40 is reduced.

[0034] Furthermore, as shown in Figures 3 to 5, the main body 30 has an axial passage 37 that connects the second opening 33 and the discharge port 52 and extends in the axial direction of the pump chamber 13. The axial passage 37 is formed continuously with the second opening 33 and is also formed in a groove shape on the inner circumferential surface of the recess 31. The axial end of the axial passage 37 (the upper side in Figure 5) communicates with the radial passage 54 and merges with the flow path 80 (see Figure 5) formed by the discharge port 52 on the cover portion 40 side, the radial passage 54, and the first opening 53. In this embodiment, the axial passage 37 is formed with a cross section perpendicular to the drive shaft 1 that extends in the radial direction of the pump portion 10 (see Figures 3 and 4). In other words, the axial passage 37 is formed in a rectangular shape with a cross section perpendicular to the drive shaft 1 that is long in the radial direction of the pump portion 10. Also, the axial passage 37 is formed with a smaller flow path cross-sectional area than the radial passage 54.

[0035] As described above, the liquid discharged from the pump chamber 13b in the discharge region is guided to the first opening 53 and the second opening 33, respectively. As shown in Figure 5, the liquid guided to the first opening 53 is guided to the discharge port 52 through the radial passage 54 and discharged (arrow A in Figure 5). On the other hand, the liquid guided to the second opening 33 merges with the flow path 80 (radial passage 54) through the axial passage 37 and is guided to the discharge port 52 and discharged (arrow B in Figure 5). Since the axial passage 37 is formed with a smaller flow path cross-sectional area than the radial passage 54, the liquid is mainly guided to the discharge port 52 through the flow path 80.

[0036] In this embodiment, the electric pump 100 has an L-shaped flow path 80. As a result, the pressure loss in the flow path 80 is relatively large. However, if the flow path 80 is formed in a straight line, the discharge port 52 will open inside the cylindrical part 45 of the cover part 40, and the discharge side and the suction side will be in communication, making it difficult to form the flow path 80 in a straight line.

[0037] Therefore, in the electric pump 100 of this embodiment, a second opening 33 and an axial passage 37 are formed in the main body 30. In the electric pump 100, a port (discharge port 52) ​​formed in the flange portion 41 communicates with the pump chamber 13b of the pump portion 10 through two passages, a radial passage 54 and an axial passage 37. In other words, since multiple passages are provided that connect the discharge port 52 and the pump chamber 13b, the cross-sectional area of ​​the entire passage can be increased. This reduces pressure loss. In this embodiment, pressure loss can be reduced on the discharge side of the electric pump 100. In addition, lubrication between the outer rotor 12 and the recess 31 of the main body 30 is improved, and friction between the two is reduced.

[0038] Furthermore, in the electric pump 100, the axial passage 37 is formed with a cross-section perpendicular to the drive shaft 1 that extends radially in the direction of the pump section 10. In other words, because the circumferential dimension of the drive shaft 1 is small, the rotating outer rotor 12 can be prevented from getting caught in the axial passage 37.

[0039] Next, we will explain how to install the electric pump 100.

[0040] Figure 6 is a side view showing the electric pump 100 attached to the mounting body 101, with the mounting body 101 shown in cross-section. The mounting body 101 is the case of equipment that utilizes the liquid discharged from the electric pump 100, and the equipment is, for example, a transmission or a transaxle device. The mounting body 101 has fastening holes (not shown) formed corresponding to the insertion holes 36 of the mounting flange 35 of the housing 20 of the electric pump 100 and into which a fixing member 70 is fastened, a housing recess 71 that accommodates a part of the main body 30 of the housing 20, a suction passage 72 formed in the center of the bottom surface of the housing recess 71 into which the cylindrical portion 45 of the cover portion 40 of the housing 20 is inserted, and a discharge passage 73 formed on the outer peripheral edge of the bottom surface of the housing recess 71. The suction passage 72 is a passage that guides liquid from the mounting body 101 to the pump section 10 of the electric pump 100, and the discharge passage 73 is a passage that guides liquid discharged from the pump section 10 of the electric pump 100 to the mounting body 101.

[0041] When attaching the electric pump 100 to the mounting body 101, the main body portion 30 of the housing 20 of the electric pump 100 is housed in the receiving recess 71 of the mounting body 101, and the mounting flange 35 of the housing 20 is brought into contact with the end face of the mounting body 101, while the cylindrical portion 45 of the cover portion 40 of the housing 20 is inserted into the suction passage 72 of the mounting body 101. Then, the fixing member 70 is inserted through the insertion hole 36 of the mounting flange 35 and fastened to the fastening hole of the mounting body 101. As a result, the mounting flange 35 is pressed against the end face of the mounting body 101, and the electric pump 100 is attached to the mounting body 101. With the electric pump 100 attached to the mounting body 101, a space 4 is formed between the cover portion 40 and the bottom surface of the receiving recess 71, connecting the discharge port 52 and the discharge passage 73, and the liquid discharged from the discharge port 52 is guided to the discharge passage 73 through the space 4. When the electric pump 100 is attached to the mounting body 101, it is preferable that the discharge port 52 of the electric pump 100 and the discharge passage 73 of the mounting body 101 face each other, as shown in Figure 6. This allows the liquid discharged from the discharge port 52 to flow axially and be guided to the discharge passage 73, thereby smoothly supplying liquid to the discharge passage 73 facing the discharge port 52. However, it is not essential that the discharge port 52 and the discharge passage 73 face each other. In other words, the discharge port 52 and the discharge passage 73 may be offset in the circumferential direction of the cylindrical portion 45. In this case, the liquid discharged axially from the discharge port 52 flows through the space 4 in the circumferential direction of the cylindrical portion 45 and is guided to the discharge passage 73.

[0042] According to the above embodiment, the following effects are achieved.

[0043] In the electric pump 100, the discharge port 52 formed in the flange portion 41 communicates with the pump chamber 13b of the pump portion 10 through the radial passage 54 and the axial passage 37. In other words, since multiple flow paths are provided that connect the discharge port 52 and the pump chamber 13b, the overall flow path cross-sectional area can be increased. This reduces pressure loss.

[0044] Next, modifications of this 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 embodiments, or to combine the configurations described in the following different modifications.

[0045] <Example 1> In the above embodiment, a suction port 51 is formed inside the cylindrical portion 45, and a discharge port 52 is formed on the flange portion 41, offset radially from the pump portion 10. However, the embodiment is not limited to this; a discharge port 52 having the same shape as the suction port 51 in the above embodiment may be formed inside the cylindrical portion 45, and a suction port 51 having the same shape as the discharge port 52 in the above embodiment may be formed on the flange portion 41. In this case, the positions of the suction passage 72 and the discharge passage 73 of the mounted body 101 are swapped. In other words, one of the suction port 51 and the discharge port 52 should be formed inside the cylindrical portion 45 as a first port, and the other of the suction port 51 and the discharge port 52 should be formed on the flange portion 41, offset radially from the pump portion 10 as a second port. In this modified example 1, the pressure loss on the suction side of the electric pump 100 can be reduced.

[0046] <Modification 2> In the above embodiment, the pump section 10 is composed of an internal gear pump. However, the configuration of the pump section 10 is not limited to this. As shown in Figure 7, for example, the pump section 110 may be composed of a vane pump having a rotor 102 connected to a drive shaft 1 and rotationally driven, a plurality of vanes 103 slidably housed in a plurality of slits 102s opening on the outer circumferential surface of the rotor 102, and a cam ring 104 having an inner circumferential cam surface 104a that the tip portions 103a of the vanes 103 slide against as the rotor 102 rotates. The cam ring 104 is housed in the recess 31. The vanes 103 are pressed in a direction (radially outward) that protrudes from the slits 102s by the fluid pressure of the back pressure chamber 105 that presses the base end portion 103b and the centrifugal force acting as the rotor 102 rotates, and the tip portions 103a of the vanes 103 slide against the inner circumferential cam surface 104a of the cam ring 104. The pump chamber 13 is partitioned by the outer circumferential surface of the rotor 102, the inner circumferential cam surface 104a, and a pair of adjacent vanes 103. Since a known configuration can be adopted for the pump section 110, a detailed explanation is omitted. In this case, the axial passage 37 is formed on the outer circumferential surface of the cam ring 104. Thus, the axial passage 37 may be formed in the pump section 110 rather than in the main body 30 of the housing 20. The axial passage 37 may also be formed on the inner circumferential surface of the recess 31, similar to the above embodiment.

[0047] <Variation 3> In the above embodiment, the discharge port 52 is formed on the flange portion 41 offset radially from the pump portion 10. However, as shown in Figures 8 and 9, the discharge port 52 may also be formed on the flange portion 41 offset axially from the pump portion 10. Specifically, as shown in Figure 8, a notch 42 is formed on the flange portion 41, in which a part of the outer peripheral edge is cut out over the entire axial length. The notch 42 is formed by cutting out a straight line tangentially from the outer peripheral edge of the flange portion 41, and the end face 30a of the main body portion 30 is exposed by the notch 42. The discharge port 52 opens into the notch 42 and is formed to open radially outward. Furthermore, the port forming portion 41b on the flange portion 41 in which the discharge port 52 is formed is formed to be raised higher than other parts of the flange portion 41. Furthermore, similar to the above embodiment, the cover portion 40 has a first opening 53 and a radial passage 54, a second opening 33 is formed in the bottom surface 31a of the recess 31, and an axial passage 37 is formed in the main body portion 30. Even with this configuration, the same effects as the above embodiment are achieved.

[0048] The configuration, operation, and effects of the embodiments of the present invention will be described below.

[0049] The electric pump 100 comprises a motor unit 15 that drives the drive shaft 1, pump units 10 and 110 connected to the drive shaft 1 that discharge liquid, and a housing 20 that houses the motor unit 15 and the pump units 10 and 110. The housing 20 has a main body 30 in which a recess 31 for housing the pump units 10 and 110 is formed, and a cover unit 40 attached to the main body 30 that seals the recess 31. The cover unit 40 has an annular flange unit 41 attached to the main body 30, a cylindrical unit 45 formed projecting axially from the flange unit 41, a suction port 51 for guiding liquid to the pump units 10 and 110, and a discharge port 52 for guiding liquid discharged from the pump units 10 and 110. Inside the cylindrical unit 45 are the suction port 51 and the discharge port A first port, which is one of the outlet ports 52, is formed on the flange portion 41, and a second port, which is the other of the suction port 51 and discharge port 52, is formed offset from the pump portions 10 and 110. The cover portion 40 further has a first opening 53 facing one axial end of the pump chamber 13 of the pump portions 10 and 110, and a radial passage 54 that connects the first opening 53 and the second port and extends radially in the pump chamber 13. A second opening 33 is formed on the bottom surface 31a of the recess 31, facing the other axial end of the pump chamber 13, and is aligned axially with the first opening 53 on either side of the pump chamber 13. The pump portions 10 and 110 or the main body portion 30 have an axial passage 37 that connects the second opening 33 and the second port and extends radially in the pump chamber 13.

[0050] In this configuration, the second port formed in the flange portion 41 communicates with the pump chamber 13 of the pump portions 10 and 110 through the radial passage 54 and the axial passage 37. In other words, since multiple passages are provided that connect the second port and the pump chamber 13, the overall cross-sectional area of ​​the passages can be increased. This reduces pressure loss.

[0051] In addition, in the electric pump 100, a suction port 51 is formed as a first port on the inside of the cylindrical portion 45, and a discharge port 52 is formed as a second port on the flange portion 41.

[0052] In this configuration, pressure loss can be reduced on the discharge side of the electric pump 100.

[0053] Furthermore, in the electric pump 100, the pump section 10 includes an inner rotor 11 having a plurality of external teeth 11a and connected to the drive shaft 1, and an outer rotor 12 having a plurality of internal teeth 12a that slide in contact with the external teeth 11a and arranged on the outside of the inner rotor 11. The axial passage 37 is formed on the inner circumferential surface of the recess 31 of the housing 20, and its cross section perpendicular to the drive shaft 1 extends radially in the pump section 10.

[0054] Furthermore, in the electric pump 100, the axial passage 37 is formed in a rectangular shape with a cross-section perpendicular to the drive shaft 1 and elongated in the radial direction of the pump section 10.

[0055] In these configurations, when the pump section 10 is an internal gear pump, the rotating outer rotor 12 can be prevented from getting caught in the axial passage 37.

[0056] In the electric pump 100, the pump section 110 includes a rotor 102 connected to the drive shaft 1 and driven to rotate, a plurality of vanes 103 slidably housed in a plurality of slits 102s opening on the outer circumferential surface of the rotor 102, and a cam ring 104 having an inner circumferential cam surface 104a that the tip portions 103a of the vanes 103 slide against as the rotor 102 rotates, and the axial passage 37 is formed on the outer circumferential surface of the cam ring 104.

[0057] In this configuration, the axial passage 37 can be easily formed when the pump section 110 is a vane pump.

[0058] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of Symbols]

[0059] 1…Drive shaft, 10, 110…Pump section, 11…Inner rotor, 11a…External teeth, 12…Outer rotor, 12a…Internal teeth, 13, 13a, 13b…Pump chamber, 15…Motor section, 20…Housing, 30…Main body, 31…Pump housing recess (recess), 31a…Bottom surface, 33…Second opening, 37…Axial passage, 40…Cover section, 41…Flange section, 45…Cylindrical section, 51…Suction port, 52…Discharge port, 53…First opening, 54…Radial passage, 100…Electric pump, 102…Rotor, 102s…Slit, 103…Vane, 103a…Tip section, 104…Cam ring, 104a…Inner circumferential cam surface

Claims

1. The motor unit that drives the drive shaft, A pump unit connected to the aforementioned drive shaft and discharging liquid, The system comprises a housing that accommodates the motor unit and the pump unit, The aforementioned housing is A main body portion having a recess formed for housing the pump portion, It has a cover portion that is attached to the main body portion and seals the recess, The aforementioned cover portion is An annular flange portion attached to the main body, A cylindrical portion is formed protruding axially from the flange portion, The pump section has a suction port for guiding liquid, It has a discharge port for guiding the liquid discharged from the pump section, A first port, which is either the suction port or the discharge port, is formed inside the cylindrical portion. The flange portion has a second port, which is the other of the suction port and the discharge port, formed offset from the pump portion. The aforementioned cover portion is The first opening facing the axial end of the pump chamber of the pump section, The pump chamber further has a radial passage that connects the first opening and the second port and extends radially, A second opening is formed on the bottom surface of the recess, facing the other axial end of the pump chamber, and is aligned axially with the first opening, with the pump chamber in between. The electric pump is characterized in that the pump section or the main body section has an axial passage that connects the second opening and the second port and extends in the axial direction of the pump chamber.

2. An electric pump according to claim 1, The suction port is formed on the inside of the cylindrical portion as the first port. An electric pump characterized in that the discharge port is formed as the second port in the flange portion.

3. An electric pump according to claim 1, The pump section comprises an inner rotor having a plurality of external teeth and connected to the drive shaft, and an outer rotor having a plurality of internal teeth that slide in contact with the external teeth and positioned outside the inner rotor. The axial passage is formed on the inner circumferential surface of the recess of the housing, and the cross section perpendicular to the drive shaft extends radially in the pump section, characterized in that it is formed in an electric pump.

4. The electric pump according to claim 3, The axial passage is characterized in that the cross-section perpendicular to the drive shaft is formed in a rectangular shape that is elongated in the radial direction of the pump section.

5. An electric pump according to claim 1, The pump section comprises a rotor connected to the drive shaft and driven to rotation, a plurality of vanes slidably housed in a plurality of slits opening on the outer circumferential surface of the rotor, and a cam ring having an inner circumferential cam surface that the tips of the vanes slide against as the rotor rotates. The electric pump is characterized in that the axial passage is formed on the outer circumferential surface of the cam ring.

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