Electric pump

Abstract

This electric pump (100) comprises a motor part (15), a pump part (10), and a housing (20) that accommodates the motor part (15) and the pump part (10). The housing (20) has a body part (30) and a cover part (40) that is attached to the body part (30) and covers the pump part (10). The cover part (40) has an annular flange part (41) that is attached to the body part (30), a cylindrical part (45) that is formed concentrically with the flange part (41) and formed so as to protrude from the flange part (41) in an axial direction, a suction port (51) for guiding a liquid to the pump part (10), and a discharge port (52) for guiding the liquid discharged from the pump part (10). One of the suction port (51) and the discharge port (52) is formed inside the cylindrical part (45), and the other of the suction port (51) and the discharge port (52) is formed in the flange part (41).

Description

Electric pump

[0005]

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

[0002] JP2015-172350A discloses an electric oil pump including a pump unit composed of a pump rotor and an outer rotor housed in a pump housing, and an electric motor unit housed in the pump housing. A pump cover is attached to the pump housing. The pump cover is formed in a cylindrical shape protruding from the surface and has a discharge port communicating with the discharge port of the pump unit, and a suction port formed side by side with the discharge port and communicating with the suction port of the pump unit.

[0003] In the electric oil pump described in JP2015-172350A, the cylindrical discharge port is provided offset from the center of the pump cover. Therefore, when installing the electric oil pump, the electric oil pump must be installed in a predetermined orientation in order to fit the discharge port into the flow path of the attached body, which takes time to install the electric oil pump. In addition, since the cylindrical discharge port is provided in a special shape offset from the center of the pump cover and the positional accuracy of the cylindrical discharge port is required, it is not easy to manufacture the pump cover.

[0004] An object of the present invention is to provide an electric pump that can be easily installed and is easy to manufacture.

[0005] According to an aspect of the present invention, there is provided an electric pump including a motor unit that drives a drive shaft, a pump unit that is connected to the drive shaft and discharges a liquid, and a housing that houses the motor unit and the pump unit. The housing has a main body portion and a cover portion attached to the main body portion and covering the pump unit. The cover portion has an annular flange portion attached to the main body portion, a cylindrical portion formed concentrically with the flange portion and protruding axially from the flange portion, a suction port that guides a liquid to the pump unit, and a discharge port that guides a liquid discharged from the pump unit. One of the suction port and the discharge port is formed inside the cylindrical portion, and the other of the suction port and the discharge port is formed in the flange portion.

[0006] Figure 1 is a perspective view of an electric pump according to an embodiment of the present invention. Figure 2 is a perspective view of the pump section of an electric pump according to an embodiment of the present invention. Figure 3 is a plan 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 is a cross-sectional view of the pump section of an electric pump according to an embodiment of the present invention. Figure 5 is a side view of an electric pump and a mounting body according to an embodiment of the present invention, with the mounting body shown in a cross-sectional view. Figure 6 is a perspective view 1 of the pump section of an electric pump according to a modification 2 of an embodiment of the present invention. Figure 7 is a perspective view 2 of the pump section of an electric pump according to a modification 2 of an embodiment of the present invention.

[0007] 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, for example, mounted on a vehicle and discharges a coolant (liquid) to cool an electric motor mounted on the vehicle, or discharges oil (liquid) to lubricate gears mounted on the vehicle. The electric pump 100 may also be used as a fluid pressure supply source that discharges a working fluid (liquid) to drive equipment. Furthermore, the electric pump 100 may be mounted on industrial machinery other than vehicles.

[0008] Figure 1 is a perspective view of the electric pump 100, Figure 2 is a perspective view of the pump section 10 of the electric pump 100, and Figure 3 is a plan view of the pump section 10. Figure 3 shows the pump section with the cover section 40, which will be described later, removed. Note that Figure 3 is a plan view of the pump section 10 as seen from below in Figure 1.

[0009] As shown in Figures 1-3, the electric pump 100 comprises a motor unit 15 (see Figure 1) that drives the drive shaft 1 (see Figure 3), a pump unit 10 connected to the drive shaft 1 that discharges liquid, a control unit 17 (see Figure 1) that controls the motor unit 15, and a housing 20 that houses the motor unit 15, the pump unit 10, and the control unit 17. The arrow in Figure 3 indicates the direction of rotation of the drive shaft 1.

[0010] The motor unit 15 has an annular stator (not shown) and a motor rotor (not shown) arranged radially inward of the stator. The motor rotor rotates around the drive shaft 1 due to the interaction between the magnetization state of the stator core and the permanent magnets (not shown) of the motor rotor. A known configuration can be used for the motor unit 15, so a detailed explanation is omitted.

[0011] As shown in Figure 3, the pump section 10 is an internal gear pump having an inner rotor 11 to which the drive shaft 1 is connected, and an outer rotor 12 positioned outside the inner rotor 11. The inner rotor 11 and the outer rotor 12 are housed in a housing 20 (specifically, a main body 30, which will be described later), and are eccentrically positioned relative to each other and covered by a cover portion 40 of the housing 20. Specifically, the center of the inner rotor 11 is positioned to coincide with the center of the drive shaft 1, and the center of the outer rotor 12 is positioned to be offset downward from the drive shaft 1 in Figure 3. The inner rotor 11 has a plurality of external teeth 11a on its outer circumference, and the outer rotor 12 has a plurality of internal teeth 12a on its inner circumference that slide against the external teeth 11a. The external teeth 11a and internal teeth 12a are formed with different numbers of teeth, and the pump chamber 13 is partitioned by adjacent external teeth 11a of the inner rotor 11 and internal teeth 12a of the outer rotor 12. Multiple pump chambers 13 are formed in the pump section 10. In this embodiment, the pump section 10 is described as an internal gear pump, but other pumps such as vane pumps may also be used.

[0012] 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.

[0013] 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.

[0014] As shown in Figures 1-3, 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 5) for attaching the electric pump 100 to the mounting body 102, as will be described later, are formed on the outer circumferential surface of the area of ​​the main body 30 that houses the motor unit 15. The mounting flanges 35 have through holes 36 (see Figure 1) through which fixing members 70 (see Figure 5), such as bolts, are inserted.

[0015] As shown in Figure 3, the main body portion 30 has an insertion hole (not shown) through which the drive shaft 1 is inserted, and a pump housing recess 31 in which the pump portion 10 is housed. The pump housing recess 31 is a recess with a circular bottom surface, and the inner rotor 11 and outer rotor 12 of the pump portion 10 are housed eccentrically within it. Specifically, the center of the pump housing recess 31 coincides with the center of the outer rotor 12 and is offset from the center of the drive shaft 1. Multiple fastening holes 32 are formed on the end face 30a of the main body portion 30, through which fastening members 50 (see Figure 2), such as bolts for attaching the cover portion 40, are fastened.

[0016] As shown in Figure 2, the cover portion 40 is provided so as to cover the pump housing recess 31 in which the inner rotor 11 and outer rotor 12 are housed. The cover portion 40 is attached to the end face 30a 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".

[0017] 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. The region on the flange portion 41 where the discharge port 52 is formed protrudes slightly in the axial direction compared to other regions. Details of the configuration of the discharge port 52 will be described later. In addition, multiple fastening holes (not shown) for fastening fastening members 50 are formed on the flange portion 41, corresponding to the fastening holes 32 on the main body portion 30 of the housing 20.

[0018] The cylindrical portion 45 is formed concentrically with the flange portion 41. In an axial view, the inner region of the cylindrical portion 45 overlaps projectively 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.

[0019] As shown in the cross-sectional view of the area around the pump section 10 in Figure 4, the suction port 51 is formed to communicate with the suction port 14a of the pump chamber 13a in the suction region (in other words, to overlap with the pump chamber 13a in the axial direction). 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 discharge port 14b of 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 suction port 14a of the pump chamber 13a.

[0020] As shown in Figure 4, the discharge port 52 is formed offset radially outward from the discharge port 14b of the pump chamber 13b to the pump section 10. On the back side of the cover section 40, a discharge passage 53 is formed that connects the discharge port 14b and the discharge port 52, extending radially from the pump section 10. One end of the discharge passage 53 communicates with the discharge port 14b, and the other end communicates with the discharge port 52. As a result, the discharge port 52 communicates with the discharge port 14b through the discharge passage 53 and discharges the liquid axially. The region in the flange section 41 where the discharge port 52 and the discharge passage 53 are formed protrudes slightly axially compared to other regions, so that even if the thickness of the flange section 41 is reduced due to manufacturing tolerances, the flow path cross-sectional area of ​​the discharge port 52 and the discharge passage 53 is secured. The discharge passage 53 may also extend diagonally in the cross-section shown in Figure 4 to connect the discharge port 14b and the discharge port 52.

[0021] As described above, in the electric pump 100 of this embodiment, the cylindrical portion 45 is formed concentrically with the flange portion 41, and in an axial view, the area inside the cylindrical portion 45 overlaps projectively with both the suction region and the discharge region. Therefore, if the discharge port 52 were formed to overlap axially with the discharge port 14b of the pump chamber 13b, the discharge port 52 would be formed inside the cylindrical portion 45, requiring the discharge side and suction side to be separated inside the cylindrical portion 45. However, in the electric pump 100, as described above, the discharge port 52 is formed offset radially outward from the discharge port 14b of the pump portion 10, and a discharge passage 53 is formed that connects the discharge port 14b and the discharge port 52, so that the discharge port 52 is formed on the flange portion 41, which is outside the cylindrical portion 45. Thus, the electric pump 100 is not configured to separate the discharge side and suction side inside the cylindrical portion 45, but rather the inside of the cylindrical portion 45 becomes the suction side and the outside of the cylindrical portion 45 becomes the discharge side. In other words, the cylindrical portion 45 separates the discharge side from the suction side.

[0022] Figure 5 is a side view showing the electric pump 100 attached to the mounting body 102, with the mounting body 102 shown in cross-section. The mounting body 102 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 102 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 102 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 102.

[0023] When attaching the electric pump 100 to the mounting body 102, the main body portion 30 of the housing 20 of the electric pump 100 is placed in the receiving recess 71 of the mounting body 102, and the mounting flange 35 of the housing 20 is brought into contact with the end face of the mounting body 102, 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 102. 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 102. As a result, the mounting flange 35 is pressed against the end face of the mounting body 102, and the electric pump 100 is attached to the mounting body 102. With the electric pump 100 attached to the mounting body 102, 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 through the space 4 to the discharge passage 73. When the electric pump 100 is attached to the mounting body 102, it is preferable that the discharge port 52 of the electric pump 100 and the discharge passage 73 of the mounting body 102 face each other, as shown in Figure 5. 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.

[0024] Thus, in the electric pump 100, the cylindrical portion 45, in which the suction port 51 is formed on the inside, is formed concentrically with the flange portion 41. Therefore, the cylindrical portion 45 can be fitted into the mounting body 102 regardless of the orientation (circumferential position) of the electric pump 100. In this embodiment, the cylindrical portion 45 can be fitted into the mounting body 102 regardless of the circumferential position of the fastening holes in the mounting body 102 for attaching the electric pump 100 by the fixing member 70, and the electric pump 100 can be easily attached. Furthermore, since high positional accuracy is not required for the cylindrical portion 45, the manufacturing of the cover portion 40 of the housing 20 is easy.

[0025] Furthermore, in the electric pump 100, since the discharge port 52 is formed on the flange portion 41, the cylindrical portion 45 can be made shorter in the axial direction than in a configuration where the discharge port 52 is formed on the side surface of the cylindrical portion 45, making the electric pump 100 more compact in the axial direction. In addition, in a configuration where the discharge port 52 is formed on the side surface of the cylindrical portion 45, a die is required to remove the discharge port 52 from the cylindrical portion 45 when manufacturing the cover portion 40, whereas in the electric pump 100 of this embodiment, a die is not required, making the manufacturing of the cover portion 40 easier.

[0026] According to the above embodiment, the following effects are achieved.

[0027] In the electric pump 100, the cylindrical portion 45, in which the suction port 51 is formed on the inside, is formed concentrically with the flange portion 41. Therefore, the cylindrical portion 45 can be fitted into the mounting body 102 regardless of the orientation of the electric pump 100, and the manufacturing of the cover portion 40 of the housing 20 is easy. Furthermore, even though the cylindrical portion 45 is formed concentrically with the flange portion 41, the discharge port 52 is formed on the flange portion 41, which is on the outside of the cylindrical portion 45. Thus, the discharge side and the suction side can be separated by the cylindrical portion 45.

[0028] 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.

[0029] <Modification 1> In the above embodiment, a suction port 51 is formed on the inside of the cylindrical portion 45, and a discharge port 52 is formed to penetrate the flange portion 41 in the axial direction. However, it is not limited to this, and a discharge port 52 having the same shape as the suction port 51 in the above embodiment may be formed on the inside of 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 to penetrate the flange portion 41 in the axial direction. In this case, the positions of the suction passage 72 and the discharge passage 73 of the mounted body 102 are swapped. In other words, one of the suction port 51 and the discharge port 52 is formed on the inside of the cylindrical portion 45, and the other of the suction port 51 and the discharge port 52 is formed to penetrate the flange portion 41 in the axial direction. Even with this configuration, the same effects as the above embodiment are achieved.

[0030] <Modification 2> In the above embodiment, when the electric pump 100 is attached to the mounting body 102, it is preferable that the discharge port 52 of the electric pump 100 and the discharge passage 73 of the mounting body 102 face each other. However, the discharge port 52 and the discharge passage 73 do not have to 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.

[0031] Furthermore, if the discharge port 52 and the discharge passage 73 do not face each other, the flange portion 41 may be formed such that the surface on which the discharge port 52 is formed is inclined radially and the outer edge is lower, as shown in Figure 6. The flange portion 41 is formed with an inclination only on the surface of the region including the discharge port 52 (the region between the fastening members 50 adjacent in the circumferential direction with the discharge port 52 in between), or with the entire circumference inclined. In this configuration, since the discharge port 52 formed on the flange portion 41 is inclined radially, the space 4 becomes longer in the axial direction than when the discharge port 52 is not inclined, and the liquid discharged from the discharge port 52 flows more easily in the circumferential direction of the cylindrical portion 45. Therefore, even if the discharge port 52 and the discharge passage 73 of the mounted body 102 do not face each other, it is possible to easily supply liquid to the discharge passage 73. Similarly, even if the suction port 51 is formed on the flange portion 41, it is possible to easily guide liquid from the suction passage 72.

[0032] Furthermore, if the discharge port 52 and the discharge passage 73 do not face each other, a wall portion 55 may be formed on the outer periphery of the flange portion 41 along the discharge port 52 formed in the flange portion 41, as shown in Figure 7. The wall portion 55 is formed continuously with the discharge port 52 and protrudes axially more than other parts of the flange portion 41. Even with this configuration, the liquid discharged from the discharge port 52 flows more easily along the wall portion 55 in the circumferential direction of the cylindrical portion 45, making it easier to supply liquid to the discharge passage 73 even if the discharge port 52 and the discharge passage 73 of the mounted body 102 do not face each other. Similarly, even if the suction port 51 is formed in the flange portion 41, it is possible to easily guide liquid from the suction passage 72.

[0033] The configuration, operation, and effects of the embodiments of the present invention will be described below.

[0034] The electric pump 100 comprises a motor unit 15 that drives the drive shaft 1, a pump unit 10 connected to the drive shaft 1 that discharges liquid, and a housing 20 that houses the motor unit 15 and the pump unit 10. The housing 20 has a main body 30 and a cover unit 40 attached to the main body 30 that covers the pump unit 10. The cover unit 40 has an annular flange unit 41 attached to the main body 30, a cylindrical unit 45 formed concentrically with the flange unit 41 and projecting axially from the flange unit 41, a suction port 51 that guides liquid to the pump unit 10, and a discharge port 52 that guides liquid discharged from the pump unit 10. One of the suction port 51 and the discharge port 52 is formed inside the cylindrical unit 45, and the other of the suction port 51 and the discharge port 52 is formed on the flange unit 41.

[0035] In this configuration, the cylindrical portion 45, on which one of the suction port 51 and the discharge port 52 is formed on the inside, is formed concentrically with the flange portion 41. Therefore, the cylindrical portion 45 can be fitted into the mounting body 102 regardless of the orientation (circumferential position) of the electric pump 100, making it easy to install the electric pump 100 and also facilitating the manufacture of the cover portion 40 of the housing 20. Furthermore, even though the cylindrical portion 45 is formed concentrically with the flange portion 41, the other of the suction port 51 and the discharge port 52 is formed on the flange portion 41, which is on the outside of the cylindrical portion 45, so the discharge side and the suction side can be separated by the cylindrical portion 45.

[0036] In addition, in the electric pump 100, the port formed in the flange portion 41 is formed to penetrate the flange portion 41 in the axial direction.

[0037] In addition, in the electric pump 100, the port formed in the flange portion 41 is formed offset in the radial direction of the pump portion 10 from the suction port 14a or discharge port 14b of the pump portion 10 with which it communicates.

[0038] In these configurations, the liquid sucked in or discharged from the port formed in the flange portion 41 flows axially, so when the port and the flow path of the mounted body 102 (suction passage 72, discharge passage 73) face each other, the liquid can be smoothly supplied to and discharged from the flow path.

[0039] Furthermore, in the electric pump 100, the flange portion 41 is formed such that the surface on which the port is formed is inclined radially and the outer edge is lower.

[0040] In this configuration, the port formed in the flange portion 41 is inclined along the radial direction, making it easier for the liquid sucked in or discharged from the port to flow circumferentially than if the port were not inclined. Therefore, it is possible to easily supply and discharge liquid into the flow path even if the flow path (suction passage 72, discharge passage 73) of the port and the mounted body 102 are not facing each other.

[0041] In addition, in the electric pump 100, a wall portion 55 is formed along the outer edge of the flange portion 41, following the port formed in the flange portion 41.

[0042] In this configuration, the liquid drawn in or discharged from the port flows more easily in the circumferential direction, making it easier to supply and discharge liquid into the flow path even if the flow path (suction passage 72, discharge passage 73) of the port and the attached body 102 are not facing each other.

[0043] 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.

[0044] This application claims priority under Japanese Patent Application No. 2024-158457, filed with the Japan Patent Office on 12 September 2024, and all contents of that application are incorporated herein by reference.

Claims

1. 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, wherein the housing has a main body portion and a cover portion attached to the main body portion and covering the pump unit, and the cover portion has an annular flange portion attached to the main body portion, a cylindrical portion formed concentrically with the flange portion and 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, wherein one of the suction port and the discharge port is formed inside the cylindrical portion, and the other of the suction port and the discharge port is formed in the flange portion.

2. An electric pump according to claim 1, wherein the port formed in the flange portion is formed to penetrate the flange portion in the axial direction.

3. An electric pump according to claim 1, wherein the port formed on the flange portion is formed offset radially from the suction port or discharge port of the pump portion with which it communicates.

4. An electric pump according to claim 1, wherein the flange portion is formed such that the surface on which the port is formed is inclined radially and the outer edge is lower.

5. An electric pump according to claim 1, wherein a wall portion is formed on the outer periphery of the flange portion along the port formed on the flange portion.

Images