JP2003129966A - Motor-driven oil pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To integrate an oil pump and a motor mutually by a simple configuration without enlarging the oil pump in the axial direction. SOLUTION: A permanent magnet 6 is arranged coaxially with a core 7 close to the core 7 which is arranged in a housing 3 and in which a coil 9 is wound around a teeth 71 by opposing to the core 7. An outer rotor 5 is fixed to the permanent magnet 6 and is rotated integrally. An internal pump PM rotated by following the rotation of the outer rotor 5 while an inner rotor 4 is eccentric for B which becomes the center of the core 7 is provided inside the outer rotor 5 to miniaturize the motor-driven oil pump in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric oil pump for electrically driving an oil pump, and more particularly to a structure of an electric oil pump in which a motor unit and an oil pump unit are integrated.

[0002]

2. Description of the Related Art Conventionally, an electric oil pump of this type discharges fluid (for example, hydraulic oil) by sucking a fluid from a suction port and discharging the fluid from a discharge port by rotating a motor to discharge the fluid. Although a fluid is circulated in a closed loop, there is known a configuration in which a motor section and an oil pump section are separate (for example, Japanese Patent Laid-Open No. 9-29138).
-58438, JP-A-11-173278).

In the structure disclosed in the above-mentioned JP-A-11-173278, a bracket having an oil passage and a bearing for the output shaft of the motor is attached in the axial direction of the motor, and a gear is internally provided on the opposite end face of the bracket. An oil pump having is attached. In addition, JP-A-9-5843
In the configuration shown in Japanese Patent Publication No. 8, the rotating shaft of the motor protrudes from the motor housing, and the housing having the mechanism of the oil pump is provided at the tip of the motor rotating shaft protruding from the motor housing.

[0004]

In both of the configurations disclosed in the above two publications, the rotary shaft of the motor projects from the motor housing, and the pump mechanism is provided in front of the motor rotary shaft projecting from the motor towsing. Therefore, it becomes large in the axial direction, and the degree of freedom in design is limited.

For driving the motor used in such a structure, a brush-equipped motor is usually used in which electric power is supplied to the commutator of the rotor by a brush so that the coil is energized by the commutator. Since a motor with a brush has an electrical contact between the brush and the commutator, if a hydraulic circuit such as hydraulic oil is installed inside the motor, the hydraulic oil flowing inside the motor may cause an electrical short circuit and a conduction failure. There is a risk of malfunction of the motor, such as abnormal wear. Therefore, it becomes difficult for the brush motor to operate in hydraulic oil, and the brush motor is not suitable for incorporating the oil pump.

Therefore, the present invention has been made in view of the above problems, and it is a technical object to integrate the oil pump and the motor with a simple structure without increasing the size in the axial direction.

[0007]

A first technical means taken to solve the above problems is a housing having an inlet and an outlet, and a plurality of teeth arranged in the housing. And a core around which a coil is wound around each tooth, a permanent magnet disposed close to and facing the core and coaxial with the core, and an outer rotor fixed to the permanent magnet to be rotatable and an inner rotor And an inscribed pump that is rotated in accordance with the rotation of the outer rotor in a state of being eccentric with respect to the center of the core, sucks fluid from the suction port, and discharges fluid from the discharge port. is there.

According to the above means, the coil is arranged in the core having the suction port and the discharge port on the core wound around the teeth, and the permanent magnet is arranged coaxially with the core in close proximity to the core. . Since the outer rotor is fixed to the permanent magnet and is integrally rotatable, and the inner rotor is provided with an inscribed pump that is rotated in accordance with the rotation of the outer rotor in a state of being eccentric with respect to the center of the core. Since the internal pump is disposed inside the core, the size in the axial direction is reduced, and the degree of freedom in design in the axial direction is improved.

Further, according to the above-mentioned structure, since the motor mainly composed of the coil, the core and the permanent magnet is a brushless motor and the internal pump is arranged inside the motor, the structure is simple. It becomes possible to integrate the motor and the oil pump. Furthermore, according to this configuration, since there is no electrical contact between the core and the permanent magnet, the fluid does not affect the electrical contact that supplies power to the coil of the motor. The reliability as an oil pump is improved.

In this case, if the core is formed integrally with the housing, the fluid does not enter the inside of the core which cooperates with the permanent magnet to generate an electromagnetic attraction force in the permanent magnet. Further, since electrical connection is not required, electrical contact failure due to fluid such as a brush motor does not occur.

A second technical means taken to solve the above-mentioned problems is a housing having an inlet and an outlet, a core arranged in the housing, having a tooth, and the tooth. A coil wound around, an annular permanent magnet rotatably disposed in close proximity to the teeth, and an outer rotor that rotates integrally with the permanent magnet,
An inner rotor that is disposed in the outer rotor, rotates eccentrically with respect to the center of the core, and follows the rotation of the outer rotor to suck the fluid from the suction port and discharge the fluid from the discharge port. It is equipped with and.

According to the above-mentioned means, the core having the teeth is arranged in the housing having the suction port and the discharge port, the coil is wound around the teeth, and the annular permanent magnet is arranged in the center of the core so as to face the teeth closely. It is rotatably arranged coaxially with. The outer rotor that rotates integrally with the permanent magnet has an inner rotor that rotates eccentrically with respect to the center of the core and that rotates following the rotation of the outer rotor. With a simple structure in which the outer rotor and the inner rotor are simply arranged, the motor and the oil pump can be integrated. Even in this case, since there is no electric contact between the core and the permanent magnet, the fluid does not affect the electric contact, and the reliability of the electric oil pump is improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view in the axial direction of the electric oil pump 1, and FIG. 2 is a sectional view in the radial direction thereof. The electric oil pump 1 includes a motor portion MT and a pump portion PM in a space formed by a resin-molded housing 3 and a housing 2 made of a metal material.

The housing 2 made of a metal material (for example, aluminum material) has a cylindrical shape having a boss portion 23 at the center,
A suction port 21 and a discharge port 22 are formed inside the boss portion 23 so as to penetrate therethrough in the axial direction. The suction port 21 sucks fluid (for example, hydraulic oil) from a fluid reservoir (for example, oil pan, reservoir, etc.), and the discharge port 22 circulates the fluid pumped up from the fluid reservoir by the electric oil pump 1. (For example, in a vehicle, an automatic transmission, an engine, etc.). A suction port 25 formed in a groove shape is formed at one end of the housing 2 in the axial direction inside the suction port 21. Similarly, at one end of the discharge port 22, a discharge port 26 formed in a groove shape is formed on one axial end surface of the housing 2. A groove portion 19 is formed on the outer diameter of the boss portion 23 of the housing 2, and an annular seal member (for example, an O-ring) is fitted in the groove portion 19 to maintain the sealing property with the housing 3. The outer diameter of the boss portion 23 is covered in the axial direction with a cylindrical housing 3 having a recessed portion that matches the shape of the boss portion 23. In this state, the one axial end faces are superposed on each other and fastened by the bolts 28.
In this case, four flange portions 35 extending in the radial direction in the circumferential direction are formed on one of the axial end portions of the housing 3 on the housing 2 side. This flange part 3
5, a ring member 37 is integrally attached, bolts 28 are inserted therethrough, and bolts 8 are screwed into attachment holes 29 provided at four locations in the housing 2, so that the housings 2, 3
Is concluded. In the housing 3, in order to increase the mounting strength of the flange portion 35, a tapered reinforcing portion 36 is formed in parallel with the cylindrical housing body at an interval slightly larger than the outer diameter of the bolt 28 in the axial direction. .

A concave portion 11 is formed inside the cylindrical housing 3 so that an annular permanent magnet 6 to be described later is arranged. The concave portion 11 is located at the center of the concave portion 11 in the radial direction from B in FIG. A recess 18 is further formed at a position slightly offset (offset), and one end of the shaft 8 is inserted into the recess 18. Similarly, the other end of the shaft 8 is formed with a recess 17 at a position slightly offset in the radial direction from the center B of the housing 2 shown in FIG. 1, and the other end of the shaft 8 is formed in the recess 17. The shaft center of the shaft 8 is provided at a position A which is inserted and is slightly displaced from the center B of the electric motor 1 in the radial direction. The inner rotor 4, which constitutes an inscribed trochoidal pump, is supported on the shaft 8 integrally with the shaft 8. Further, the housing 3 includes the housing 2
Like the suction port 25 and the discharge port 26 formed in
The suction port 45 and the discharge port 46 having the same diameter are formed.

The housing 3 is formed by integrally molding a motor portion MT other than the permanent magnet 6 serving as a rotating rotor with a resin, and the housing 3 is connected to an external connector (not shown) and protrudes in the axial direction. 31 is provided. The connector 31 includes a disk-shaped terminal holder 32 integrally formed with the housing 3 on the connector side.
A substantially L-shaped terminal 33 is fixed to one end of the connector 33. One end of the terminal 33 projects into the opening 34 of the connector 31 to be electrically connected to an external connector (not shown).

The core 7 provided in the housing 3 has a disk-like outer shape, and as shown in FIGS. 1 and 2, a number of cores 7 are coaxially laminated in the axial direction. An insulator 75 is attached to the core 7 in order to maintain electrical insulation from the coil 9 wound around the core 7. Specifically,
Explaining the core 7, the core 7 disposed inside the cylindrical housing 3 has a disk-shaped outer shape, and a plurality of cores 7 (for example, coincide with B shown in FIG. 1) are provided toward the center of the core 7. For example, this embodiment has six teeth 71. The teeth 71 have flanges 72 that extend to both sides in the circumferential direction on the inner diameter side, and the inner diameter of the flange 72 is a circumferential surface 73 centered on the arcuate B. An insulator 75 for electrically insulating the core 7 is attached to the outer peripheral surface of the tooth 71 and the inner peripheral surface between the teeth so as to enclose the inner shape of the core 7 having the teeth 71. The coil 9 is wound around the six teeth 71 so as to surround each tooth 71 in the circumferential direction while maintaining electrical insulation from the teeth 7. The coil 9 wound around the tooth 71 is wound in series with the tooth 71 located diagonally with respect to the center B of the core 7 shown in FIG. Three sets of coils 9 are wound in series between two teeth 71 by diagonal winding, and one end of the coil ends of these three sets is commonly connected and brought to the terminal holder 32. Then, the other three coil ends are brought to the terminal holder 32 and fixed in a star connection. As a result, four terminals are individually provided on the terminal boulder. With such a configuration, the coil 9 is energized by applying a drive signal to the terminal 33 having a substantially L shape protruding into the opening 34 of the connector 31. In this case, the laminated core 7 in which the coil 9 is wound around the tooth 71 is integrally resin-molded together with the terminal 33 and the terminal holder 32, and the resin film made of resin is uniformly formed on the circumferential surface 73. It This makes it possible to prevent the fluid existing in the suction ports 25, 45 and the discharge ports 26, 46 from entering from the circumferential surface 73 of the tooth 71 to the outer diameter side and affecting the generation of electromagnetic force.

On the other hand, inside the tooth 71, the N pole and the S pole are kept at a predetermined distance from the circumferential surface 73 of the tooth 71.
An annular permanent magnet 6 whose poles are alternately repeated in the circumferential direction is arranged coaxially with the core 7. On the inner peripheral surface of the annular permanent magnet 6, the inner rotor (trochoidal) outer rotor 5 is aligned with the center B of the core 7 shown in FIG. , Annular permanent magnet 6
Are fixed integrally with the outer rotor 5.

Further, inside the inscribed outer rotor 5, an inscribed (trochoidal) inner rotor 4 fixed by an eccentric shaft 8 to the core center is rotatably arranged. The rotation axis of the inner rotor 4 is displaced from the center B of the core 7 in the radial direction, and the rotation of the permanent magnet 6 is
That is, when the outer rotor 5 fixed to the permanent magnet 6 rotates, the inner rotor 4 is eccentric, so that the inner rotor 4 is suspended along the inner peripheral surface of the outer rotor 5 and is driven to rotate. When the inner rotor rotates,
Inner peripheral surface (inner wall) of outer rotor 5 and inner rotor 4
The fluid (for example, hydraulic oil) that has entered the suction ports 25 and 45 through the suction port 21 in the space between the outer peripheral surface (outer wall) of the discharge port 2 and the discharge port 2 by the action of the oil pump.
The inner rotor 4 and the outer rotor 5 become an inscribed type pump PM by being pumped out to 6, 46 and discharged to the discharge port 22.

Next, the operation of the electric oil pump 1 will be described. The electric oil pump 1 configured as described above can drive the motor unit MT and the pump unit PM by connecting an external connector (not shown) to the connector 31. That is, when the external connector is connected to the connector 31 and a drive signal is given, the four terminals 33 inside the connector are energized to the coil 9 wound around the teeth 71. By energizing the coil 9, the circumferential surface 73 inside the tooth 71 is
Electromagnetic force is generated between the permanent magnet 6 and
The permanent magnet 6 is rotated by a known drive sequence by a star connection of the motor so that a rotational force is generated in the circumferential direction of the permanent magnet 6 in which the poles and the S poles are alternately repeated in the circumferential direction. It is sucked in the direction and rotates.

When the permanent magnet 6 is rotated by the electromagnetic attraction force, the outer rotor 5 fixed to the permanent magnet 6 rotates about B which is the center of the core. On the other hand, since the eccentric inner rotor 4 is rotatably arranged with respect to the shaft 8 in the inner diameter of the outer rotor 5, when the outer rotor 5 rotates, the inner rotor 4 is rotated by the outer rotor 5.
Eccentrically rotates along the inner peripheral surface of. As a result, when the fluid flows from the suction port 21 into the space formed between the outer peripheral surface of the inner rotor 4 and the inner peripheral surface of the outer rotor 5, that is, the space formed by the suction ports 25 and 45, Due to the eccentric relative rotation between the inner rotor 4 and the outer rotor 5, the suction ports 25, 45 to the discharge port 26,
It functions as an oil pump that pumps the fluid to 46 and discharges the fluid from the discharge port 22.

[0023]

According to the above-mentioned invention, the coil is arranged on the core wound around the tooth in the housing having the suction port and the discharge port, and the permanent magnet is arranged coaxially with the core so as to be closely opposed to the core. To be done. Since the outer rotor is fixed to the permanent magnet and is integrally rotatable, and the inner rotor is provided with an inscribed pump that is rotated in accordance with the rotation of the outer rotor in a state of being eccentric with respect to the center of the core. Since the inscribed pump can be arranged inside the core, the size in the axial direction can be reduced, and the degree of freedom in design in the axial direction can be improved.

Further, since the motor and the oil pump can be integrated with a simple structure and no electric contact exists between the core and the permanent magnet, the fluid is a motor. The electric contact for feeding power to the coil is not affected, and the reliability of the electric oil pump can be improved.

In this case, if the core is formed integrally with the housing, a fluid can be prevented from entering the inside of the core which cooperates with the permanent magnet to generate an electromagnetic attraction force in the permanent magnet. .

Further, according to the present invention described above, the core having the teeth is disposed in the housing having the suction port and the discharge port, the coil is wound around the teeth, and the annular permanent magnet is closely faced to the teeth to face the teeth. It is rotatably arranged coaxially with the center of the core. The outer rotor that rotates integrally with the permanent magnet has an inner rotor that rotates eccentrically with respect to the center of the core and that rotates following the rotation of the outer rotor. The motor and the oil pump can be integrated with a simple structure in which the outer rotor and the inner rotor are simply arranged. Even in this case, the electrical contact can be eliminated between the core and the permanent magnet, the fluid does not affect the electrical contact, and the reliability of the electric oil pump can be improved.

[Brief description of drawings]

FIG. 1 is an axial sectional view of an electric oil pump according to an embodiment of the present invention.

FIG. 2 is a radial cross-sectional view of the electric oil pump according to the embodiment of the present invention.

[Explanation of symbols]

1 Electric oil pump 2,3 housing 4 Inner rotor (internal pump) 5 Outer rotor (internal pump) 6 permanent magnet 7 core 8 shafts 9 coils 21 suction port 22 Discharge port 25,45 suction port 26,46 Discharge port 71 Teeth 73 Circumferential surface MT motor section PM pump (internal pump)

Claims (3)

[Claims] 1. A housing having an intake port and a discharge port, a core disposed in the housing, having a plurality of teeth, around which a coil is wound, and a core closely facing the core. And a permanent magnet coaxially arranged with the outer rotor are fixed to the permanent magnet to be rotatable, and the inner rotor is eccentric to the center of the core and is rotated by the rotation of the outer rotor. An electric oil pump, comprising: an internal pump that sucks fluid from the suction port and discharges the fluid from the discharge port. 2. The electric oil pump according to claim 1, wherein the core is integrally molded with the housing. 3. A housing having an intake port and a discharge port, a core provided in the housing and having teeth, a coil wound around the teeth, and a rotatably arranged in close proximity to the teeth. An annular permanent magnet that is provided, an outer rotor that rotates integrally with the permanent magnet, and an outer rotor that is disposed in the outer rotor, rotates eccentrically with respect to the center of the core, and is driven by the rotation of the outer rotor. And an inner rotor that sucks fluid from the suction port and discharges the fluid from the discharge port.