CN110500272B

CN110500272B - Electric pump

Info

Publication number: CN110500272B
Application number: CN201910405507.8A
Authority: CN
Inventors: 藤川透
Original assignee: Aisin Co Ltd
Current assignee: Aisin Co Ltd
Priority date: 2018-05-18
Filing date: 2019-05-16
Publication date: 2022-08-09
Anticipated expiration: 2039-05-16
Also published as: CN110500272A; JP7081298B2; US20190353168A1; JP2019199872A

Abstract

An electric pump (1) comprising: a motor housing (32); a pump housing adjacent the motor housing; a rotor (34) housed in the motor housing and axially supported by the rotary shaft (15); a stator (33) disposed radially outside the rotor and mounted to the motor housing; a pump unit (10) accommodated in the pump housing and configured to suck and discharge a fluid by rotation of the rotor; and a cup-shaped shield (60) disposed between the rotor and the stator to prevent fluid in the pump unit from being introduced into the stator. A seal member (65) is provided between the shield case and the motor housing, and a communication path (70) that communicates the inside and the outside of the shield case is formed between the motor housing and the pump housing at a position closer to the opening side of the shield case than the seal member.

Description

Electric pump

Technical Field

The present invention relates to an electric pump.

Background

The electric pump is used, for example, to supply hydraulic oil to a hydraulic device such as a transmission mounted on a vehicle. In such an electric pump, in order to improve the cooling efficiency of the motor unit, a part of the hydraulic oil discharged from the electric pump may be circulated through the rotor of the motor unit. However, when hydraulic oil is introduced into the stator of the motor unit, the operation of the motor unit may be hindered. Therefore, in order to avoid introduction of hydraulic oil into the stator, a shield (can) is provided between the stator and the rotor supported on the rotating shaft in the motor unit (e.g., JP2015-218650a (reference 1)).

An electric pump may have higher motor efficiency when the distance between the stator and the rotor is smaller. The shielding provided between the stator and the rotor should therefore have as small a thickness as possible. The interior of the shielding sleeve is configured as a sealed closed space, which is separate from the exterior, of the pump unit, so that hydraulic oil introduced into the rotor is not discharged toward the stator. Therefore, when hydraulic oil is introduced from the pump unit into the inside of the shield sleeve, the hydraulic pressure inside the shield sleeve rises. In the case where the shield sleeve is configured to have a small thickness, the shield sleeve may be deformed due to the influence of the hydraulic pressure rise inside the shield sleeve. In addition, the shield sleeve may be damaged due to an increase in the amount of deformation. The function of the motor unit in the electric pump is greatly impaired.

Therefore, there is a need for an electric pump that can easily avoid deformation of the shield sleeve.

Disclosure of Invention

According to an aspect of the present invention, the electric pump is characterized in that the electric pump includes a motor housing, a pump housing adjacent to the motor housing, a rotor accommodated in the motor housing and axially supported by a rotary shaft, a stator provided radially outside the rotor and mounted to the motor housing, a pump unit accommodated in the pump housing and configured to suck and discharge a fluid by rotation of the rotor, and a cup-shaped shield can (can) provided between the rotor and the stator to prevent the fluid in the pump unit from being introduced into the stator, wherein a seal member is provided between the shield can and the motor housing, and a communication path communicating an inside of the shield can and an outside of the shield can is formed between the motor housing and the pump housing at a position closer to an opening side of the shield can than the seal member.

With this configuration, even when the fluid in the pump unit is introduced into the rotor of the motor unit, the fluid in the pump unit can be prevented from being introduced into the stator by the shield case and the seal member provided between the shield case and the motor housing. Among them, in the motor unit, when a fluid is introduced into the shield shell (rotor), the fluid pressure is raised due to an increase in the amount of the fluid in the shield shell. Thus, with this configuration, the communicating path is formed on the opening side of the shield shell so as to communicate the inside of the shield shell and the outside of the shield shell. By the communication path, the fluid introduced into the inside of the shield sleeve is easily discharged to the outside of the shield sleeve. Thus, since the fluid pressure is prevented from rising even when the fluid is introduced into the inside of the shield sleeve, the shield sleeve is effectively prevented from being deformed even when the thickness of the shield sleeve is small. Therefore, by reducing the thickness of the shield sleeve, the motor efficiency of the electric pump can be increased.

Another feature is that the shield sleeve has a flange provided on an end portion of the opening side thereof and extending radially outward between the motor case and the pump case, the seal member is elastically deformable and provided between the motor case and the flange, and the flange of the shield sleeve is configured to abut against the seal member in a state of having a clearance with the motor case, the communication path being formed by narrowing the clearance.

With this configuration, the flange of the shield case abuts against the seal member and is spaced apart from the motor housing. Wherein when the hydraulic pressure rises due to an increase in the amount of fluid in the shield shell, the hydraulic pressure acts on the flange of the shield shell so that the flange presses the seal member. At this time, the flange approaches the motor case due to the elastic deformation of the seal member. That is, the gap between the flange and the motor case is reduced, and a communication path is formed between the flange and the end surface of the pump case so as to communicate the inside of the shield sleeve and the outside of the shield sleeve. That is, since the fluid can be discharged from the communication path, even when the fluid is introduced into the inside of the shield sleeve, the fluid pressure inside the shield sleeve can be prevented from rising. Therefore, even when the shield sleeve has a shape with a small thickness, deformation of the shield sleeve can be effectively avoided.

In addition, since the shield sleeve is disposed in a state where the flange is pressed against the end face of the pump housing, the inside of the shield sleeve can be configured as a sealed closed space. With the above configuration, introduction of foreign substances from the outside into the inside of the shield case can be prevented.

Another feature is that the shield sleeve has a flange provided on an end portion of the opening side thereof and extending radially outward between the motor case and the pump case, the seal member is elastically deformable and provided between the motor case and the flange, and the flange of the shield sleeve is pressed by the seal member to close the communication path.

With this configuration, the flange is pressed by the elastic force of the seal member to close the communication path. Wherein the communication path may be kept closed when the fluid pressure inside the shield sleeve is not so high as to deform the cap (in the case of low fluid pressure). I.e. as little fluid as possible, so that no more fluid is unnecessarily discharged to the outside of the shielding.

Drawings

The foregoing and other features, aspects, and advantages of the present invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of an electric pump as disclosed herein;

fig. 2 is a sectional view of a main portion of the electric pump;

fig. 3 is a sectional view of a main portion of the electric pump;

FIG. 4 is a schematic view of a shielding sleeve; and

fig. 5 is a sectional view of a main portion of an electric pump according to another embodiment.

Detailed Description

Embodiments disclosed herein will be explained below with reference to the accompanying drawings.

As shown in fig. 1, the electric pump 1 includes a pump unit 10, a motor unit 30, and a driver unit 50. The electric pump 1 is used as an oil pump, for example, and supplies hydraulic oil to a transmission of a vehicle. In addition, the electric pump 1 may be used to supply a fluid other than hydraulic oil.

Pump unit 10 includes a pump housing 12 having a circular accommodation recess 18 formed in one end surface thereof, and a pump cover 11 covering the end surface of pump housing 12 in which accommodation recess 18 is formed. The pump housing 12 and the pump cover 11 are made of aluminum alloy. A bearing hole 19 eccentric to the center of the accommodation recess 18 is formed in the pump housing 12. The rotation shaft 15 is inserted into the bearing hole 19, so that the rotation shaft 15 is rotatably supported through the bearing hole 19.

The pump 14 disposed in the accommodation recess 18 includes an inner rotor 22 formed with external teeth and an outer rotor 23 formed with internal teeth, the inner rotor 22 and the outer rotor 23 being meshed with each other. The outer peripheral surface of the outer rotor 23 is supported in the accommodation recess 18 so as to be rotatable. The inner rotor 22 is press-fitted and mounted to one end of the rotating shaft 15 so as to be coaxial with the rotating shaft 15. The other end portion of the rotary shaft 15 opposite to the side where the inner rotor 22 is mounted protrudes from the pump housing 12 toward the motor unit 30.

A pump chamber 24 is formed between the teeth of the inner rotor 22 and the outer rotor 23 engaged with each other, and the volume of the pump chamber 24 increases or decreases according to the rotation. The pump cover 11 is thus formed with a discharge path 25 through which the hydraulic oil in the pump chamber 24 is discharged, and a suction path 26 through which the hydraulic oil is sucked through the suction path 26.

The motor unit 30 includes an annular stator 33 and a cylindrical rotor 34, the annular stator 33 and the cylindrical rotor 34 being accommodated in the motor housing 32, the rotor 34 being disposed radially inward from an inner peripheral surface of the stator 33 by a predetermined distance, the rotor 34 being axially supported on the rotary shaft 15. The motor housing 32 is disposed adjacent the pump housing 12. The stator 33 and the rotor 34 are coaxial with the axis of the rotary shaft 15. The rotor 34 includes a rotor core 35 formed by laminating thin electromagnetic steel plates and permanent magnets 36 accommodated in a plurality of slots formed in the rotor core 35. The rotor 34 is disposed radially inward of the stator 33 so as to face the stator 33 mounted to the motor case 32.

The stator 33 includes a stator core 39 formed by laminating electromagnetic steel sheets and a coil 40 wound on a coil support frame 41 formed of an insulator. A cylindrical space 37 is formed between the inner peripheral side of the stator 33 and the rotor 34.

The driver unit 50 is disposed on the opposite side of the motor unit 30 from the pump unit 10. The driver unit 50 is configured such that a printed circuit board 53 is provided in a driver housing portion 52, electronic components are mounted on the printed circuit board 53, and the driver housing portion 52 is formed by combining the motor housing 32 and the cover portion 51 with each other. The driver unit 50 generates an alternating magnetic field by energizing the coils 40 of the stator 33 to rotate the rotor 34. The inner rotor 22 is rotated via the rotation shaft 15 by the rotation of the rotor 34, and the outer rotor 23 is rotated in accordance with the rotation of the inner rotor 22. Thus, the hydraulic oil circulating through the suction path 26 is sucked to the pump chamber 24 and discharged from the discharge path 25.

A cup-shaped (bottom cylindrical) shield 60 is provided in the cylindrical space 37 of the rotor 34 as shown in fig. 4. The shield case 60 is formed of a plate material such as a nonmagnetic material (e.g., stainless steel), and is formed in a bottom cylindrical shape. The outer peripheral diameter of the shield 60 and the inner diameter of the cylindrical space 37 are substantially the same, and the side surface of the shield 60 is disposed between the stator 33 and the rotor 34. That is, the rotor 34 is housed within the shielding sleeve 60. The shielding sleeve 60 has an opening 61 on the side of the pump unit 10 and a flange 62 beside the opening 61. The flange 62 extends radially outwardly between the motor housing 32 and the pump housing 12. A seal member 65 is provided between the flange 62 and the end face 42 of the motor housing 32 on the side of the pump unit 10. The sealing member 65 is configured as an elastically deformable O-ring, for example, with portions of the sealing member 65 received in a circular groove 43 formed in the end face 42. A gap 73 is formed between the flange 62 of the shielding sleeve 60 and the end face 42 facing the flange 62. The shield 60 is held by the flange 62 and is pressed against the end face 27 of the pump housing 12 on the side of the motor unit 30 by the elastic force of the seal member 65 in a state where the flange 62 abuts against the seal member 65 (see fig. 2).

When the pump 14 rotates and hydraulic oil is drawn into the pump chamber 24, a part of the hydraulic oil in the pump chamber 24 circulates through a gap between the bearing hole 19 and the rotary shaft 15 and is introduced into the shield case 60. When the amount of hydraulic oil introduced into the shield case 60 is small and the hydraulic pressure in the shield case 60 is in a low pressure state, as shown in fig. 2, the flange 62 of the shield case 60 is pressed against the end face 27 of the pump housing 12 on the side of the motor unit 30 by the seal member 65. Thereby, the interior of the shielding sleeve 60 is kept in a closed state different from the sealing of the pump unit 10 with respect to the outside.

Meanwhile, when hydraulic oil is introduced into the shield case 60 and the hydraulic pressure in the shield case 60 rises to a high pressure state during operation of the electric pump 1, as shown in fig. 3, the hydraulic pressure of the hydraulic oil acts on the flange 62, and the flange 62 pushes up the seal member 65 toward the end face 42 of the motor case 32. At this time, the seal member 65 is pressed and elastically deformed, and the flange 62 comes close to the end face 42 of the motor case 32. That is, the gap 73 between the flange 62 and the end surface 42 of the motor housing 32 is reduced, and a communication gap 70 (an example of a communication path) is formed between the flange 62 and the end surface 27 of the pump housing 12, thereby communicating the inside of the shield case 60 (the side where the rotor 34 is accommodated) with the outside of the shield case 60. In this way, the communication gap 70 is formed as a communication path between the flange 62 and the end surface 27 of the pump housing 12 on the motor unit 30 side. In this way, even when the hydraulic oil is introduced into the shield case 60 and enters a high-pressure state, since the hydraulic oil is discharged from the communication gap 70 toward the outside of the shield case 60, a further increase in the hydraulic pressure inside the shield case 60 is avoided. Therefore, even when the shield case 60 has a shape with a small thickness, deformation of the shield case 60 can be effectively avoided.

As shown in fig. 2 and 3, in a state in which the gap 72 is formed between the end face 42 and the end face 27 by a collar 80 having a thickness larger than that of the motor housing 32, the motor housing 32 and the pump housing 12 are fastened and fixed to each other by bolts 81. Thereby, the hydraulic oil circulating through the communication gap 70 and reaching inside the shield case 60 outside the shield case 60 further circulates through the gap 72 and is discharged outside the electric pump 1. Even when the hydraulic oil is discharged to the outside of the electric pump 1, for example, in the case where the electric pump 1 is provided in the oil tank, since the hydraulic oil discharged to the outside of the electric pump 1 is discharged to the oil tank, no problem occurs. For example, when the electric pump 1 is disposed outside the oil tank, the electric pump 1 may be configured to return the hydraulic oil discharged to the outside of the electric pump 1 to an oil pan (not shown) or to the suction path 26 through an oil path (not shown).

In the state shown in fig. 2, when the length of the seal member 65 in the direction perpendicular to the flange 62 is defined as a height H and the magnitude of the gap 73 between the end face 42 of the motor case 32 and the flange 62 of the shield case 60 is defined as a width T, the width T is set with respect to the height H so that "width T/height H" is in the range from 5% to 50%. When the "width T/height H" is less than 5%, the gap 73 is too small, and a sufficient amount of the communication gap 70 cannot be secured when the gap 73 is too small, so that the hydraulic oil may not be appropriately discharged from the inside of the shield case 60. Meanwhile, when the "width T/height H" exceeds 50%, the seal member 65 easily protrudes from the groove 43 in the end face 42, and the sealing function of the seal member 65 may be impaired.

Second embodiment

As shown in fig. 5, in the second embodiment, the groove 28 is formed in the end face 27 of the pump housing 12 in the direction in which the flange 62 extends, and the groove 28 forms a communication path 71 that communicates the inside of the shield case 60 with the outside of the shield case 60. The communication path 71 communicates with a gap 72 between the end surface 42 of the motor housing 32 and the end surface 27 of the pump housing 12. The inside of the shield sleeve 60 and the outside of the shield sleeve 60 are always communicated with each other through the communication path 71 regardless of the hydraulic pressure inside the shield sleeve 60. Thereby, the hydraulic oil introduced into the shield case 60 can be discharged to the outside of the electric pump 1 through the communication path 71 and the clearance 72. The communication path 71 (groove 28) is formed in a singular or plural number.

In the present embodiment, even when the amount of hydraulic oil introduced into the shield case 60 is small and the hydraulic pressure is in a low pressure state, the hydraulic oil can be discharged out of the shield case 60 through the communication path 71. Therefore, since the hydraulic oil is discharged from the communication path 71, the hydraulic pressure is prevented from rising. Therefore, even when the introduced amount of the hydraulic oil is increased, the inside of the shield case 60 can be maintained in a low pressure state. Thereby, deformation of the shield cover 60 can be effectively avoided even when the thickness of the shield cover 60 is small as compared with the first embodiment. Therefore, by reducing the thickness of the shield case 60, the motor efficiency of the electric pump 1 is increased.

In addition, in the present embodiment, since the inside and the outside of the shield case 60 are always communicated with each other due to the presence of the communication path 71, there is a possibility that intrusion of foreign substances and introduction of air from outside the electric pump 1 may occur through the communication path 71. Therefore, the depth of the communication path 71 (groove 28) can be made as small as possible, thereby avoiding intrusion of foreign substances and introduction of air as much as possible. In addition, in order to avoid intrusion of foreign substances from outside the electric pump 1, a filter for collecting foreign substances may be provided at a predetermined position of the passage connected to the communication path 71 of the electric pump 1.

Other embodiments

(1) Although the second embodiment illustrates an example in which the groove 28 is formed in the end face 27 of the pump housing 12 so as to form the communication path 71, a groove may be formed in the flange 62 of the shield sleeve 60 so as to form the communication path 71, or a groove may be formed in both the end face 27 and the flange 62 so as to form the communication path 71.

(2) Although the embodiment illustrates an exemplary shape in which the shielding sleeve 60 has the flange 62, the shielding sleeve 60 may be configured without the flange 62. In this case, a communication path is formed between at least a part of the end of the opening 61 in the shield case 60 and the end face 27 of the pump housing 12 so as to communicate the inside of the shield case 60 with the outside of the shield case 60. The communication path may be formed, for example, by providing a notch in the end of the opening 61 in the shield 60, or may be formed by providing a groove in the end face 27 of the pump housing 12. In addition, the communication path may be formed by both a notch in the shield sleeve 60 and a groove in the end face 27 of the pump housing 12.

(3) The groove may be formed in one or both of the end face 42 and the end face 27, the end face 42 and the end face 27 facing each other between the motor housing 32 and the pump housing 12, so that the communication path communicates outside the electric pump 1. In this case, the gap 72 is not required.

The invention can be widely used for the electric pump with the shielding sleeve.

The foregoing description illustrates the principles, preferred embodiments and modes of operation of the present invention. However, the scope of the invention is not limited to the specific embodiments disclosed. Furthermore, the embodiments described herein are to be considered as illustrative and not restrictive. Various changes, modifications, and equivalents may be made without departing from the spirit of the invention. Accordingly, it is noted that the scope of the invention is to cover all variations, modifications and equivalents falling within the spirit and scope of the invention as claimed.

Claims

1. An electric pump (1) comprising:

a motor housing (32);

a pump housing adjacent to the motor housing;

a rotor (34), said rotor (34) being housed in said motor housing and being axially supported by a rotary shaft (15);

a stator (33), the stator (33) being disposed radially outward of the rotor and mounted to the motor housing;

a pump unit (10) housed in the pump housing and configured to suck and discharge a fluid by rotation of the rotor; and

a cup-shaped shielding sleeve (60), the cup-shaped shielding sleeve (60) being arranged between the rotor and the stator to avoid introduction of fluid in the pump unit into the stator,

the shielding sleeve has a flange (62), the flange (62) being disposed on an open-side end thereof and extending radially outward between the motor housing and the pump housing,

an elastically deformable sealing member (65) is provided between the motor case and the flange,

the flange of the shield sleeve is configured to abut against the seal member in a state of having a clearance with the motor case,

when the hydraulic pressure in the inside of the shield shell rises, the seal member is elastically deformed and the gap is made smaller, whereby a communication path (70) is formed between the flange and the end surface of the pump housing and on the opening side closer to the shield shell than the seal member, the communication path (70) communicates the inside of the shield shell and the outside of the shield shell, and the fluid flowing into the inside of the shield shell can be discharged to the outside via the communication path.

2. The electric pump as set forth in claim 1,

the flange of the shield sleeve is pressed by the seal member to close the communication path.