PUMP APPARATUS

1. FIELD OF THE INVENTION

The present invention relates to a pump apparatus.

2. BACKGROUND

Recently, electric oil pumps used for transmissions and the like have been required to have responsiveness. In order to realize responsiveness in an electric oil pump, there is a need to increase the output of a motor for an electric oil pump.

When a motor for an electric oil pump has a high output, a large current flows in a coil of the motor, so that the temperature of the motor becomes high, and a permanent magnet of the motor may be demagnetized, for example. Therefore, in order to curb temperature rise of the motor, there is a need to provide a cooling structure in the motor.

Japanese Patent Laid-open No. 2008-125235 discloses an electric motor including an oil supply mechanism in which a relative positional relationship between a stator and a rotor in an axial direction is displaced using an oil pressure of an oil according to a rotation speed of the rotor and the rotor is cooled by the oil.

However, in the electric motor disclosed in Japanese Patent Laid-open No. 2008-125235, a stator and a rotor cannot be cooled at the same time using an oil.

SUMMARY

Example embodiments of the present invention provide pump apparatuses each including a stator and a rotor that are cooled at the same time and achieves a high cooling effect without having degrading pump efficiency.

According to an example embodiment of the present disclosure, a pump apparatus includes a motor including a shaft rotatably supported about a central axis extending in an axial direction, and a pump on one side of the motor in the axial direction, is driven by the shaft extending from the motor, suctions an oil, and delivers the oil to the motor. The motor includes a rotor rotating around the shaft, a stator disposed to face the rotor, a housing accommodating the rotor and the stator, and a discharge port provided in the housing to discharge the oil. The pump includes a pump rotor attached to the shaft, a pump case accommodating the pump rotor, a suction port provided in the pump case to suction the oil, and a delivery port provided in the pump case to deliver the oil to the motor. The suction port, the delivery port, and the discharge port are disposed at positions different from each other when viewed in the axial direction. The pump apparatus includes a first flow channel to suction the oil into the pump through the suction port of the pump using a negative pressure in the pump, a second flow channel to deliver the oil to an inside of the motor through the delivery port of the pump using pressurization of the pump, a third flow channel provided between the stator and the rotor, a fourth flow channel provided between the stator and the housing, and a fifth flow channel to discharge the oil inside the motor through the discharge port.

According to example embodiments of the present disclosure, it is possible to provide pump apparatuses in each of which a stator and a rotor are cooled at the same time and a structure achieves a high cooling effect without degrading pump efficiency.

The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a pump apparatus according to a first example embodiment of the present disclosure.

FIG. 2 is a view of a pump body viewed from a front side in an axial direction.

FIG. 3 is a view schematically illustrating a main portion of the pump apparatus according to the first example embodiment of the present disclosure.

FIG. 4 is a top view of a stator in the first example embodiment of the present disclosure.

FIG. 5 is a view illustrating a modification example of a discharge port in the first example embodiment of the present disclosure.

FIG. 6 is a view illustrating a modification example of a second flow channel and a fifth flow channel in the first example embodiment of the present disclosure.

FIG. 7 is a view illustrating another modification example of the second flow channel and the fifth flow channel in the first example embodiment of the present disclosure.

FIG. 8 is a cross-sectional view illustrating a pump apparatus according to a second example embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, with reference to the drawings, pump apparatuses according to example embodiments of the present invention will be described. The scope of the present invention is not limited to the following example embodiments and can be arbitrarily changed within a range of the technical ideas of the present invention. In addition, in the following drawings, in order to facilitate the understanding of each constitution, there are cases where the scales, the numbers, or the like of respective structures differ from those of the actual structures.

In addition, in the drawings, an XYZ coordinate system is suitably indicated as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, a Z-axis direction is a direction parallel to one direction which is an axial direction of a central axis J illustrated in FIG. 1. An X-axis direction is a direction parallel to a length direction of a bus bar assembly 60 illustrated in FIG. 1, that is, a traverse direction in FIG. 1. A Y-axis direction is a direction parallel to a width direction of the bus bar assembly 60, that is, a direction orthogonal to both the X-axis direction and the Z-axis direction.

In addition, in the following description, a positive side in the Z-axis direction (positive Z-side) will be referred to as “a front side”, and a negative side in the Z-axis direction (negative Z-side) will be referred to as “a rear side”. The rear side and the front side are names simply used for description and do not limit actual positional relationships or directions. In addition, unless otherwise specified, the direction (Z-axis direction) parallel to the central axis J will be simply referred to as “an axial direction”. A radial direction about the central axis J will be simply referred to as “a radial direction”. A circumferential direction about the central axis J, that is, a direction (θ-direction) around the central axis J will be simply referred to as “a circumferential direction”.

In this specification, the expression “extending in the axial direction” includes a case of extending in a direction inclined within a range of less than 45° with respect to the axial direction, in addition to the case of strictly extending in the axial direction (Z-axis direction). In addition, in this specification, the expression “extending in the radial direction” includes a case of extending in a direction inclined within a range of less than 45° with respect to the radial direction, in addition to the case of strictly extending in the radial direction, that is, a direction perpendicular to the axial direction (Z-axis direction).

First Example Embodiment

FIG. 1 is a cross-sectional view illustrating a pump apparatus 10 of the present example embodiment.

The pump apparatus 10 of the present example embodiment has a shaft 41, a motor section 20, a housing 12, a cover 13, and a pump section 30. The shaft 41 rotates about the central axis J extending in the axial direction. The motor section 20 and the pump section 30 are provided side by side in the axial direction.

As illustrated in FIG. 1, the motor section 20 has the cover 13, a rotor 40, a stator 50, a bearing 42, a control device 70, the bus bar assembly 60, and a plurality of O-rings. The plurality of O-rings include at least a rear O-ring 82.

The rotor 40 is fixed to an outer circumferential surface of the shaft 41. The stator 50 is positioned on an outer side of the rotor 40 in the radial direction. That is, the motor section 20 is an inner rotor motor. The bearing 42 rotatably supports the shaft 41. The bearing 42 is held by the bus bar assembly 60. The bus bar assembly 60 is connected to an external power source and supplies a current to the stator 50.

The housing 12 holds the motor section 20 and the pump section 30. The housing 12 is open on the rear side (negative Z-side), and an end portion of the bus bar assembly 60 on the front side (positive Z-side) is inserted into an opening portion of the housing 12. The cover 13 is fixed to the rear side of the housing 12. The cover 13 covers the rear side of the motor section 20. That is, the cover 13 covers at least a part of the bus bar assembly 60 on the rear side (negative Z-side) and is fixed to the housing 12. Hereinafter, there are cases where the housing 12 will be referred to as a member including the cover 13.

The control device 70 is disposed between the bearing 42 and the cover 13. The rear O-ring 82 is provided between the bus bar assembly 60 and the cover 13. Hereinafter, each component will be described in detail.

As illustrated in FIG. 1, the housing 12 has a tubular shape. In more detail, the housing 12 has a multi-stage cylindrical shape in which both ends about the central axis J are open. The material of the housing 12 is a metal, for example. The housing 12 holds the motor section 20 and the pump section 30. The housing 12 has a tube portion 14 and a housing side flange portion 15.

The housing side flange portion 15 extends outward in the radial direction from an end portion of the tube portion 14 on the rear side. The tube portion 14 has a cylindrical shape about the central axis J. The tube portion 14 has a bus bar assembly insertion portion 21a, a stator holding portion 21b, and a pump body holding portion 21c in the axial direction (Z-axis direction) from the rear side (negative Z-side) to the front side (positive Z-side) in this order.

The bus bar assembly insertion portion 21a surrounds an end portion of the bus bar assembly 60 on the front side (positive Z-side) from the outer side of the central axis J in the radial direction. Each of the bus bar assembly insertion portion 21a, the stator holding portion 21b, and the pump body holding portion 21c has a concentrically cylindrical shape, and the diameters thereof become smaller in this order.

That is, the end portion of the bus bar assembly 60 on the front side is positioned on the inner side of the housing 12. An outer surface of the stator 50, that is, an outer surface of a core back portion 51 (which will be described below) is fitted onto an inner surface of the stator holding portion 21b. Accordingly, the stator 50 is held in the housing 12. An outer circumferential surface of a pump body 31 is fixed to an inner circumferential surface of the pump body holding portion 21c.

The housing 12 has a discharge port 12b. The discharge port 12b discharges an oil, which has been delivered to the motor section 20 from the pump section 30, to the outside of the pump apparatus 10. In the example illustrated in FIG. 1, the discharge port 12b is provided on a side surface of the housing 12. In detail, the discharge port 12b is positioned in the tube portion 14 of the housing 12 and between one end of the stator 50 on a side opposite to the pump section in the axial direction and a bottom portion of the housing 12. The bottom portion of the housing 12 is a rear end portion of the housing 12 and is a front end portion of the control device 70 and the bus bar assembly 60.

That is, the discharge port 12b is positioned on the side surface of the housing 12 and on the side in front of the control device 70 and the bus bar assembly 60 in the axial direction. The position of the discharge port 12b is not limited to the position illustrated in FIG. 1. The discharge port 12b may be provided at an arbitrary position in the housing 12 and may be provided in the bottom portion of the housing 12, for example.

In the present example embodiment, a control device and a bus bar assembly are disposed in the bottom portion of the housing 12. However, disposition of the control device and the bus bar assembly is not limited thereto. For example, they may be attached to a side surface of the motor section 20 or the like. In this case, a lid portion 22b of the cover 13 becomes the bottom portion of the housing, and a tubular portion 22a of the cover 13 is included on the side surface of the housing.

An optimal position can be selected as the position of the discharge port 12b in accordance with the position of the pump apparatus 10 inside an external apparatus to which the pump apparatus 10 is attached. For example, in the present example embodiment, it is conceivable that the pump apparatus 10 be attached to a continuously variable transmission (CVT) while being disposed as follows. When the pump apparatus 10 is disposed such that the axial direction extends horizontally, and when the pump apparatus 10 is disposed such that the negative side in the X-axis direction (negative X-side) becomes the upper side and the positive side in the X-axis direction (positive X-side) becomes the lower side with respect to the shaft 41, the discharge port 12b may be provided at a position above the shaft 41 in a direction of gravity.

That is, when the pump apparatus 10 is disposed such that the direction of gravity becomes a positive X-direction in FIG. 1, and when the negative X-side becomes the upper side and the positive X-side becomes the lower side with respect to the shaft 41, the discharge port may be provided at a position symmetrical about the shaft 41 with respect to the discharge port 12b illustrated in FIG. 1. The discharge port 12b is provided on the upper side in the direction of gravity in this manner due to the following reason. Inside the motor section 20, an oil warmed by absorbing heat of the rotor 40 and the stator 50 is likely to be biased upward in the direction of gravity, and a cold oil is likely to be biased downward in the direction of gravity. Therefore, a hot oil can be discharged from the motor section 20 with priority by providing the discharge port 12b on the upper side in the direction of gravity.

In the present example embodiment, an oil which has been suctioned into the pump apparatus 10 through a suction port 32c of the pump section 30 is delivered to the inside of the motor section 20 from a delivery port 31c and is discharged to the CVT (external apparatus) through the discharge port 12b of the motor section 20. When the pump apparatus 10 is attached to the CVT, the pump apparatus 10 is built inside a transmission case (not illustrated), for example. The transmission case has a discharge port (not illustrated), and an oil which has been discharged through the discharge port 12b of the pump apparatus 10 is discharged to the CVT via the discharge port of the transmission case.

The number of discharge ports 12b to be provided is not limited to one, and a plurality of discharge ports 12b may be provided. When a plurality of discharge ports 12b are provided, each of the discharge ports 12b may be provided at an arbitrary position on the side surface or in the bottom portion of the housing 12 as described above. In addition, a plurality of discharge ports 12b may be provided on both the side surface and the bottom portion of the housing 12. An oil inside the motor section 20 can be more efficiently discharged by providing a plurality of discharge ports 12b.

<Rotor>

The rotor 40 has a rotor core 43 and a rotor magnet 44. The rotor core 43 surrounds the shaft 41 in a direction around an axis (θ-direction) and is fixed to the shaft 41. The rotor magnet 44 is fixed to the outer surface in a direction around the axis of the rotor core 43. The rotor core 43 and the rotor magnet 44 rotate integrally with the shaft 41.

The stator 50 surrounds the rotor 40 in the direction around the axis (θ-direction) and rotates the rotor 40 around the central axis J. The stator 50 has the core back portion 51, teeth portions 52, coils 53, and insulators (bobbins) 54. The shape of the core back portion 51 is a concentrically cylindrical shape with respect to the shaft 41.

The teeth portions 52 extend toward the shaft 41 from the inner surface of the core back portion 51. A plurality of teeth portions 52 are provided to be disposed at equal intervals in the circumferential direction of the inner surface of the core back portion 51 (FIG. 4). The coil 53 is constituted of a wound conductive wire 53a. The coil 53 is provided in the insulator (bobbin) 54. The insulator (bobbin) 54 is mounted in each teeth portion 52.

The bearing 42 is disposed on the rear side (negative Z-side) of the stator 50. The bearing 42 is held by a bearing holding portion 65 of a bus bar holder 61 (which will be described below). The bearing 42 supports the shaft 41. The constitution of the bearing 42 is not particularly limited, and any known bearing may be used.

The control device 70 controls driving of the motor section 20. The control device 70 has a circuit board (not illustrated), a rotation sensor (not illustrated), a sensor magnet holding member (not illustrated), and a sensor magnet 73. That is, the motor section 20 has a circuit board, a rotation sensor, a sensor magnet holding member, and the sensor magnet 73.

The circuit board outputs a motor drive signal. The position of the sensor magnet holding member is set when a hole at the center is fitted to a small diameter part of the end portion of the shaft 41 on the rear side (negative Z-side). The sensor magnet holding member can rotate together with the shaft 41. The sensor magnet 73 has a ring shape in which N poles and S poles are alternately disposed in the circumferential direction. The sensor magnet 73 is fitted onto the outer circumferential surface of the sensor magnet holding member.

Accordingly, the sensor magnet 73 is held by the sensor magnet holding member and is disposed to be rotatable with the shaft 41 in a direction around the axis (positive θ-direction) of the shaft 41 on the rear side (negative Z-side) of the bearing 42.

The rotation sensor is attached to the front surface of the circuit board on the front side (positive Z-side) of the circuit board. The rotation sensor is provided at a position facing the sensor magnet 73 in the axial direction (Z-axis direction). The rotation sensor detects a change in magnetic flux of the sensor magnet 73. The rotation sensor is a Hall IC or an MR sensor, for example. Specifically, when a Hall IC is used, three Hall ICs are provided.

<Cover>

The cover 13 is attached to the rear side (negative Z-side) of the housing 12. The material of the cover 13 is a metal, for example. The cover 13 has the tubular portion 22a, the lid portion 22b, and a cover side flange portion 24. The tubular portion 22a is open on the front side (positive Z-side).

The tubular portion 22a surrounds the bus bar assembly 60, in more detail, the end portion of the bus bar holder 61 on the rear side (negative Z-side) from the outer side of the central axis J in the radial direction. The tubular portion 22a is coupled to the end portion of the bus bar assembly insertion portion 21a on the rear side in the housing 12 via the housing side flange portion 15 and the cover side flange portion 24.

The lid portion 22b is connected to the end portion of the tubular portion 22a on the rear side. In the present example embodiment, the lid portion 22b has a flat plate shape. The lid portion 22b blocks the opening portion of the bus bar holder 61 on the rear side. The surface of the lid portion 22b on the front side comes into contact with the whole circumference of the rear O-ring 82. Accordingly, the cover 13 indirectly comes into contact with the rear surface of a main body portion on the rear side of the bus bar holder 61 via the rear O-ring 82 throughout the circumference around the opening portion of the bus bar holder 61.

The cover side flange portion 24 extends outward in the radial direction from the end portion of the tubular portion 22a on the front side. The housing 12 and the cover 13 are bonded to each other while the housing side flange portion 15 and the cover side flange portion 24 overlap each other.

The external power source is connected to the motor section 20 via a connector portion 63. The connected external power source is electrically connected to a bus bar 91 and a wiring member 92 protruding from the bottom surface of a power supply opening portion 63a of the connector portion 63. Accordingly, a drive current is supplied to the coils 53 of the stator 50 and the rotation sensor via the bus bar 91 and the wiring member 92. For example, a drive current supplied to the coils 53 is controlled in accordance with the rotation position of the rotor 40 measured by the rotation sensor. When a drive current is supplied to the coils 53, a magnetic field is generated and the rotor 40 rotates due to this magnetic field. In this manner, the motor section 20 obtains a rotation driving force.

The pump section 30 is positioned on one side of the motor section 20 in the axial direction, in detail, on the front side (positive Z-axis side). The pump section 30 is driven by the shaft 41 extending from the motor section 20. The pump section 30 has a pump case and a pump rotor 35. The pump case has the pump body 31 and a pump cover 32. Hereinafter, the pump cover 32 and the pump body 31 will be referred to as the pump case.

The pump body 31 is fixed to the inside of the housing 12 on the front side of the motor section 20. An O-ring 71 is attached to the pump body 31. The O-ring 71 is provided between the outer circumferential surface of the pump body 31 and the inner circumferential surface of the housing 12 in the radial direction. Accordingly, a space between the outer circumferential surface of the pump body 31 and the inner circumferential surface of the housing 12 in the radial direction is sealed. The pump body 31 has a pump chamber 33 which is depressed to the rear side (negative Z-side), that is, the other side in the axial direction from the surface on the front side (positive Z-side), that is, one side in the axial direction and accommodates the pump rotor 35. The shape of the pump chamber 33 viewed in the axial direction is a circular shape.

The pump body 31 is open at both ends in the axial direction to allow the shaft 41 to pass therethrough and has a penetration hole 31a in which an opening on the front side is open in the pump chamber 33. An opening of the penetration hole 31a on the rear side is open on the motor section 20 side. The penetration hole 31a functions as a bearing member which rotatably supports the shaft 41.

The pump body 31 has an exposed portion 36 which is positioned on the side in front of the housing 12 and is exposed to the outside of the housing 12. The exposed portion 36 is a part of the end portion of the pump body 31 on the front side. The exposed portion 36 has a columnar shape extending in the axial direction. The exposed portion 36 overlaps the pump chamber 33 in the radial direction. The pump section 30 is a positive-displacement pump which performs pressure-feeding of an oil by increasing and decreasing the volume of a sealed space (oil chamber) and is a trochoid pump in the present example embodiment. Hereinafter, using FIG. 2, details of the trochoid pump will be described.

FIG. 2 is a view of the pump body 31 viewed from the front side in the axial direction.

The pump rotor 35 is attached to the shaft 41. In more detail, the pump rotor 35 is attached to the end portion of the shaft 41 on the front side.

The pump rotor 35 has an inner rotor 37 which is attached to the shaft 41, and an outer rotor 38 which surrounds the outer side of the inner rotor 37 in the radial direction. The inner rotor 37 has a ring shape. The inner rotor 37 is a gear having teeth on the outer surface in the radial direction. The inner rotor 37 is fixed to the shaft 41. In more detail, the end portion of the shaft 41 on the front side is press-fitted into the inner rotor 37. The inner rotor 37 rotates together with the shaft 41 in the direction around the axis (O-direction).

The outer rotor 38 has a ring shape surrounding the outer side of the inner rotor 37 in the radial direction. The outer rotor 38 is a gear having teeth on the inner surface in the radial direction. The outer rotor 38 is rotatably accommodated inside the pump chamber 33. An inner accommodation chamber 39 accommodating the inner rotor 37 is formed in the outer rotor 38, and the inner accommodation chamber 39 is formed to have a star shape. The inner rotor 37 is rotatably accommodated in the inner accommodation chamber 39.

The number of inner teeth of the outer rotor 38 is set to be more than the number of outer teeth of the inner rotor 37. The inner rotor 37 and the outer rotor 38 mesh with each other. When the inner rotor 37 is rotated by the shaft 41, the outer rotor 38 rotates in accordance with the rotation of the inner rotor 37. That is, the pump rotor 35 rotates due to rotation of the shaft 41. In other words, the motor section 20 and the pump section 30 have the same rotation axis. Accordingly, the pump apparatus 10 can be prevented from having an increased size in the axial direction.

When the inner rotor 37 and the outer rotor 38 rotate, the volume of a space formed between the inner rotor 37 and the outer rotor 38 changes in accordance with their rotation positions. The pump rotor 35 suctions an oil through a suction port 74 by utilizing a volume change and discharges the suctioned oil through a discharge port 75 by pressurizing the oil. When the pump apparatus 10 is in operation, a region where the volume decreases has a higher pressure than a region where the volume increases, that is, a region into which the oil is suctioned.

In the present example embodiment, in the space formed between the inner rotor 37 and the outer rotor 38, the region where the volume increases is defined as a negative pressure region, and the region where the volume decreases is defined as a pressurization region. An oil is suctioned into the region where the volume increases, and an oil is discharged out from the region where the volume decreases. The pump rotor 35 can suction an oil through the suction port 32c by utilizing a volume change and can discharge the suctioned oil through the delivery port 31c by pressurizing the oil.

The suction port 32c is disposed on one side of the negative pressure region of the pump rotor 35 in the axial direction. In addition, the delivery port 31c is disposed on the other side of the pressurization region of the pump rotor 35 in the axial direction. Here, an oil which has been suctioned into the pump chamber 33 through the suction port 32c is accommodated in a volume part between the inner rotor 37 and the outer rotor 38 and is sent to the delivery port 31c side. Thereafter, the oil is delivered to the motor section 20 through the delivery port 31c.

The pump section 30 is not limited to a trochoid pump, and a pump of any type may be adopted as long as the pump is a positive-displacement pump performing pressure-feeding of an oil by increasing and decreasing the volume of the sealed space (oil chamber). For example, the pump section 30 may be a vane pump. When the pump section 30 is a vane pump, a cylindrical rotor (not illustrated) fixed to the shaft 41 is accommodated in the pump chamber 33. The rotor (not illustrated) has a plurality of slots and vanes slidably mounted in the slots. The outer circumference of the rotor is disposed to be eccentric with respect to the inner circumference of the pump chamber 33, so that a crescent-shaped space is generated between the pump chamber 33 and the rotor.

The crescent-shaped space generated between the pump chamber 33 and the rotor is divided into a plurality of regions by the slots mounted in the rotor. When the rotor rotates and the vanes mounted in the slots move forward and rearward, the volume of each region changes in accordance with the rotation position. Similar to the case of a trochoid pump, an oil can be suctioned through a suction port (not illustrated) by utilizing a volume change and the suctioned oil can be discharged through the discharge port (not illustrated) by pressurizing the oil. In each region formed between the rotor and the pump chamber 33, the region where the volume increases is the negative pressure region and the region where the volume decreases is the pressurization region.

Description returns to the pump section (FIG. 1). The pump cover 32 is attached to the front side of the pump body 31. The pump cover 32 has a pump cover main body 32a. The pump cover main body 32a has a disk shape extending in the radial direction. The pump cover main body 32a blocks the opening of the pump chamber 33 on the front side.

The pump section 30 has the suction port 32c and the delivery port 31c. The suction port 32c is provided in the pump cover 32. In detail, the suction port 32c is open at both ends of the pump cover 32 in the axial direction and has a cylindrical shape extending in the axial direction. The opening portion of the suction port 32c on the rear side is connected to the negative pressure region of the pump chamber 33. Since an oil is suctioned through the suction port 32c due to a negative pressure in the pump section 30, an oil can be efficiently suctioned when the suction port 32c is connected to the negative pressure region.

The position of the suction port 32c is not limited to the position illustrated in FIG. 1. The suction port 32c may be provided at an arbitrary position in the pump cover 32 and may be provided in the pump body 31. An optimal position can be selected as the position of the suction port 32c in accordance with the position inside the external apparatus to which the pump apparatus 10 is attached. For example, when an oil pan (not illustrated) serving as a supply source of an oil is on the pump cover 32 side, an oil can reach the suction port 32c at the shortest distance without providing an unnecessary flow channel, by providing the suction port 32c at the position illustrated in FIG. 1.

In addition, for example, when the supply source of an oil is on the side surface of the pump apparatus 10, an oil can reach the suction port 32c at the shortest distance without providing an unnecessary flow channel, by providing the suction port 32c on the side surface of the pump body 31. In detail, the suction port 32c can be easily connected to the negative pressure region of the pump chamber 33 by providing the suction port 32c in the pump body 31, that is, a part constituting a wall portion of the pump chamber. The wall portion of the pump chamber is a part of a cylindrical shape of the pump body 31 extending in the axial direction.

The delivery port 31c is provided in the pump body 31. In detail, the delivery port 31c is open at both ends of the pump body 31 in the axial direction and has a cylindrical shape extending in the axial direction. The opening portion of the delivery port 31c on the front side is provided on a surface of the pump body 31 facing the pump cover 32 and is connected to the pressurization region of the pump chamber 33. Since an oil which has been suctioned into the pump chamber 33 through the suction port 32c is delivered to the motor section 20 due to pressurization of the pump section 30, an oil can be efficiently delivered when the delivery port 31c is connected to the pressurization region.

The position of the delivery port 31c is not limited to the position illustrated in FIG. 1. The delivery port 31c may be provided at an arbitrary position in the pump body 31 as long as the delivery port 31c can be connected to the pressurization region of the pump chamber 33 at the position. For example, when the pump apparatus 10 is disposed such that the axial direction extends horizontally, the delivery port 31c may be provided at a position below the shaft 41 in the direction of gravity.

That is, when the pump apparatus 10 is disposed such that the direction of gravity becomes a negative X-direction in FIG. 1, and when the positive X-side becomes the upper side and the negative X-side becomes the lower side with respect to the shaft 41, the delivery port may be provided at a position symmetrical about the shaft 41 with respect to the delivery port 31c illustrated in FIG. 1. The delivery port 31c is provided on the lower side in the direction of gravity in this manner due to the following reason. Inside the motor section 20, an oil warmed by absorbing heat of the rotor 40 and the stator 50 is likely to be biased upward in the direction of gravity, and a cold oil is likely to be biased downward in the direction of gravity. Therefore, a cold oil can be delivered to the lower side of the motor section 20 with priority by providing the delivery port 31c on the lower side in the direction of gravity.

The suction port 32c and the delivery port 31c are disposed at positions different from each other in the circumferential direction with reference to the central axis J. The reason for this is that the pressurization region and the negative pressure region are present in the positive-displacement pump at positions different from each other in the circumferential direction. When the suction port 32c and the delivery port 31c are disposed at positions different from each other in the circumferential direction with reference to the central axis J, the suction port 32c can be disposed on the negative pressure region side and the delivery port 31c can be disposed on the pressurization region side. Therefore, as described above, an oil can be efficiently suctioned into the pump section 30 and can be delivered to the motor section 20.

In addition, in FIG. 3, the suction port 32c, the delivery port 31c, and the discharge port 12b are disposed at positions different from each other when viewed in the axial direction of the pump apparatus 10. Moreover, a cross-sectional area of the delivery port 31c is smaller than a cross-sectional area of the discharge port 12b. The cross-sectional area of the delivery port 31c indicates the opening area at the narrowest place in the opening of the delivery port 31c extending in the axial direction. Similarly, the cross-sectional area of the discharge port 12b indicates the opening area at the narrowest place in the opening of the discharge port 12b extending in the axial direction.

In pump apparatuses in the related art, an oil which had been suctioned from a pump section was pressurized to be discharged from the pump section. In contrast, in the pump apparatus 10 of the present example embodiment, an oil which has been suctioned from the pump section 30 is pressurized and is discharged thereafter via the inside of the motor section 20. Here, an oil which has been discharged from the motor section 20 requires a discharge pressure equivalent to that in the pump apparatuses in the related art. Thus, the discharge pressure of an oil has to predominate when being delivered to the motor section 20 from the pump section 30.

When the cross-sectional area of the delivery port 31c is smaller than the cross-sectional area of the discharge port 12b, a discharge loss increases. However, the discharge pressure which has been generated in the pump section till then can be maintained using a discharge pressure from the inside of the motor to the outside of the motor. That is, it is possible to provide a structure in which the discharge pressure from the inside of the motor section 20 to the outside of the motor section 20 is not degraded.

The cross-sectional area of the delivery port 31c may be larger than the cross-sectional area of the discharge port 12b. In this case, the discharge pressure from the inside of the motor section 20 to the outside of the motor section 20 can be further improved than the discharge pressure from the pump section 30 to the inside of the motor section 20.

Next, a cooling structure of the pump apparatus 10 according to the present example embodiment will be described. According to the present example embodiment, an oil which has been supplied to the pump chamber 33 through the suction port 32c of the pump section 30 is delivered to the motor section 20 through the delivery port 31c by the pump rotor 35. The oil cools the stator 50 and the rotor 40 at the same time by circulating inside the motor section 20 and is discharged to the external apparatus via the discharge port 12b of the motor section 20.

FIG. 3 is a view schematically illustrating a main portion of the pump apparatus 10 in order to facilitate the understanding of flow channels for an oil in the pump apparatus 10 illustrated in FIG. 1.

As illustrated in FIG. 3, the pump apparatus 10 has a first flow channel 1 for suctioning an oil into the pump section 30 through the suction port 32c of the pump section 30 using a negative pressure in the pump section 30, a second flow channel 2 for delivering an oil to the inside of the motor section 20 through the delivery port 31c of the pump section 30 using pressurization of the pump section 30, a third flow channel 3 provided between the stator 50 and the rotor 40, a fourth flow channel 4 provided between the stator 50 and the housing 12, and a fifth flow channel 5 for discharging an oil inside the motor section 20 through the discharge port 12b of the motor section 20. Hereinafter, details of each flow channel will be described.

The first flow channel 1 in FIG. 3 is provided in the pump cover 32 and leads to the inside of the pump section 30 through the suction port 32c. In detail, the suction port 32c has a first opening portion 32d in the front end portion of the pump cover 32 and has a second opening portion 32e near the negative pressure region of the pump chamber 33. The first flow channel 1 leads to the inside of the pump section 30 via the first opening portion 32d and the second opening portion 32e of the suction port 32c.

The position of the first flow channel 1 is not limited to the position illustrated in FIG. 3 and is determined in accordance with the position of the suction port 32c. The position of the suction port 32c can be provided at an arbitrary position in the pump case as described above. For example, when the suction port 32c penetrates the pump body 31 from the outer circumferential surface of the exposed portion 36 to a place near the negative pressure region of the pump chamber 33, the first flow channel 1 is provided in the pump body 31.

The second flow channel 2 in FIG. 3 is provided in the pump body 31 and leads to the inside of the motor section 20 through the delivery port 31c. In detail, the delivery port 31c has a first opening portion 31d in the front end portion of the pump body 31, that is, near the pressurization region of the pump chamber 33 and has a second opening portion 31e in the rear end portion of the pump body 31.

The second flow channel leads to the inside of the motor section 20 via the first opening portion 31d and the second opening portion 31e of the delivery port 31c. An oil which has been suctioned into the negative pressure region inside the pump section 30 from the first flow channel is pressurized by the pump rotor 35 and flows to one end of the second flow channel on the front side, that is, the first opening portion 31d of the delivery port 31c from the pressurization region inside the pump section 30.

The third flow channel 3 in FIG. 3 is provided between the stator 50 and the rotor 40. In the example illustrated in FIG. 3, the third flow channel 3 is positioned between the inner circumferential surface of the stator 50 and the outer circumferential surface of the rotor 40. An oil which has flowed into the motor section 20 from the second flow channel 2 flows to one end on the rear side from one end on the front side of the third flow channel 3.

The third flow channel 3 is not limited to a place between the inner circumferential surface of the stator 50 and the outer circumferential surface of the rotor 40. For example, as illustrated in FIG. 4, a penetration hole 51b may be provided in the core back portion 51 of the stator 50, and the penetration hole 51b may be used as the third flow channel 3. In addition, a space between a plurality of teeth portions 52 (between teeth adjacent to each other) disposed away from each other in the core back portion 51 may be used as the third flow channel 3.

When the penetration hole 51b of the core back portion 51 or a space between the teeth portions 52 adjacent to each other is used as a flow channel for an oil, the coils 53 of the stator 50 can be more efficiently cooled and the rotor 40 can be cooled.

Similar to the stator 50, a penetration hole (not illustrated) or a cut-out portion (not illustrated) may be provided in the rotor core 43, and the penetration hole or the cut-out portion may be used as the third flow channel 3. When the penetration hole or the cut-out portion of the rotor core 43 is used as a flow channel, the rotor 40 can be more efficiently cooled and the rotor magnet 44 can be prevented from being demagnetized. That is, the third flow channel 3 may be provided at an arbitrary position as long as the position is between the stator 50 and the rotor 40.

The fourth flow channel 4 in FIG. 3 is provided between the stator 50 and the housing 12. In detail, the fourth flow channel 4 is provided between the outer circumferential surface of the stator 50 and the inner circumferential surface of the housing 12. When the pump apparatus 10 has the fourth flow channel 4, an oil can more efficiently circulate between the pump section 30 and the motor section 20 and the motor section 20 can be cooled with high efficiency.

The fourth flow channel 4 joins to the third flow channel 3 on the rear side and leads to the discharge port 12b. An oil which has flowed into the motor section 20 via the second flow channel 2 is divided into an oil flowing to the third flow channel 3 and an oil flowing to the fourth flow channel 4. The oil which has flowed to the fourth flow channel 4 flows to one end on the rear side from one end on the front side of the fourth flow channel 4. Then, the oil which has flowed to the rear side merges with the oil from the third flow channel 3 and is discharged to the outside of the pump apparatus 10 via the discharge port 12b.

Since the surface area of the stator 50 which comes into contact with an oil can be increased by providing the fourth flow channel 4, the inside of the motor section 20 can be more efficiently cooled. Generally, coils radiate the most heat in a motor. Heat radiated by the coils is transferred to the core back portion 51 and the teeth portions 52. That is, the stator 50 has a significant heat radiation quantity in the motor section 20. Thus, if the stator 50 can be efficiently cooled, the motor section 20 can be efficiently cooled.

As illustrated in FIG. 4, the fourth flow channel 4 may have a cut-out portion 51a on the outer circumferential surface of the core back portion 51. In addition, the fourth flow channel 4 may have a cut-out portion 12a on the inner circumferential surface of the housing 12. The fourth flow channel 4 may have both or any one of the cut-out portion 51a and the cut-out portion 12a.

When the stator 50 has the cut-out portion 51a, the surface area of the stator 50 which comes into contact with an oil can be increased. Therefore, the inside of the motor section 20 can be more efficiently cooled. In addition, when the stator 50 has the cut-out portion 51a, or when the housing 12 has the cut-out portion 12a, the flow rate of an oil flowing to the fourth flow channel 4 can be increased. Therefore, an oil can more efficiently circulate.

The fifth flow channel 5 in FIG. 3 is provided in the tube portion 14 of the housing 12 and leads to the outside of the pump apparatus 10 through the discharge port 12b. The fifth flow channel 5 varies depending on the position of the discharge port 12b. The position of the discharge port 12b is not limited to the positions illustrated in FIGS. 1 and 3. As described above, the discharge port 12b can be provided at an arbitrary position on the side surface of the housing 12 and in the bottom portion (cover 13) of the housing.

An example in which the discharge port 12b is provided at another position will be described below using FIG. 5. Oils which have flowed into the third flow channel 3 and the fourth flow channel 4 individually flow to the rear side from the front side and are discharged from the fifth flow channel 5. In the present example embodiment, an oil which has been discharged to the outside of the pump apparatus 10 from the fifth flow channel is discharged to the CVT through the discharge port of the transmission case through the inside of the transmission case or the like in which the pump apparatus 10 is built.

In the present example embodiment, the stator 50 is molded using a resin. That is, the stator 50 is an integrally molded product formed of a resin 50a. When the stator 50 is an integrally molded product formed of a resin, the surface area of the stator 50 which comes into contact with an oil can be increased in the third flow channel 3 and the fourth flow channel 4 (which will be described below). Therefore, the inside of the motor section 20 can be more efficiently cooled.

Similar to the stator 50, the rotor 40 may be molded using a resin. That is, the rotor 40 may be an integrally molded product formed of a resin. When the rotor 40 is molded, the surface area of the rotor 40 which comes into contact with an oil can be increased in the third flow channel 3. Therefore, the rotor magnet 44 can be prevented from being demagnetized and the motor can be more efficiently cooled.

According to the present example embodiment, the pump apparatus 10 has the motor section 20 that has the shaft 41 rotatably supported about the central axis J extending in the axial direction; and the pump section 30 that is positioned on one side of the motor section 20 in the axial direction, is driven by the shaft 41 extending from the motor section 20, suctions an oil, and delivers the oil to the motor section 20. The motor section 20 has the rotor 40 rotating around the shaft 41, the stator 50 disposed to face the rotor 40, the housing 12 accommodating the rotor 40 and the stator 50, and the discharge port 12b provided in the housing 12 to discharge an oil. The pump section 30 has the pump rotor 35 attached to the shaft 41, the pump case accommodating the pump rotor 35, the suction port 32c provided in the pump case to suction an oil, and the delivery port 31c provided in the pump case to deliver an oil to the motor section 20. In the pump apparatus 10, the suction port 32c, the delivery port 31c, and the discharge port 12b are disposed at positions different from each other when viewed in the axial direction. The pump apparatus 10 has the first flow channel 1 for suctioning an oil into the pump section 30 through the suction port 32c of the pump section 30 using a negative pressure in the pump section 30, the second flow channel 2 for delivering an oil to the inside of the motor section 20 through the delivery port 31c of the pump section 30 using pressurization of the pump section 30, the third flow channel 3 provided between the stator 50 and the rotor 40, the fourth flow channel 4 provided between the stator 50 and the housing 12, and the fifth flow channel 5 for discharging an oil inside the motor section 20 through the discharge port 12b.

According to the present example embodiment, an oil which has been suctioned into the pump section 30 through the suction port 32c due to a negative pressure in the pump section 30 and has been delivered to the motor section 20 through the delivery port 31c due to pressurization of the pump section 30 flows inside the motor section 20 and cools the stator 50 and the rotor 40 at the same time. In the present example embodiment, an oil which has been suctioned into the pump section 30 is not divided into an oil to be discharged to the external apparatus and an oil for cooling the motor section 20, and an oil which has been suctioned into the pump section 30 is delivered to the motor section 20. Therefore, cooling of the stator 50 and the rotor 40 can be realized at the same time without having the pump efficiency being degraded. In addition, according to the present example embodiment, in the pump apparatus 10, the stator 50 can be cooled from both the housing 12 side and the rotor 40 side by including the third flow channel 3 and the fourth flow channel 4. Therefore, the stator 50 can be efficiently cooled. That is, it is possible to provide a structure having a high cooling effect for curbing temperature rise in the motor section 20.

MODIFICATION EXAMPLE OF DISCHARGE PORT

In the example illustrated in FIG. 3, the discharge port 12b is positioned in the tube portion 14 of the housing 12, that is, on the side surface of the housing and between the rear end portion of the stator 50 and the rear end portion (bottom portion) of the housing 12. However, the position of the discharge port 12b is not limited thereto and may be provided at an arbitrary position in the housing 12. In addition, the discharge port 12b may be provided in the cover 13. As a modification example of the discharge port 12b, a case where the discharge port 12b is provided in the bottom portion of the housing 12 will be described below.

FIG. 5 is a view illustrating a case where the discharge port 12b is provided in the bottom portion of the housing 12.

In FIG. 5, different from the example illustrated in FIG. 1, the control device 70 is attached to a part other than the bottom portion of the motor section 20, for example, a side surface. In addition, in FIG. 5, the lid portion 22b of the cover 13 becomes the bottom portion of the housing, and the tubular portion 22a of the cover 13 is included on the side surface of the housing.

The fifth flow channel 5 in FIG. 5 is a flow channel leading to the outside of the pump apparatus 10 through the discharge port 12b in the bottom portion of the housing 12. The first flow channel 1 to the fourth flow channel 4 are similar to those of the example illustrated in FIG. 3. In the present modification example, oils which have flowed into the third flow channel 3 and the fourth flow channel 4 individually flow to the rear side from the front side and are discharged from the fifth flow channel 5 illustrated in FIG. 5. In this manner, the discharge port 12b can be provided in the bottom portion of the housing 12, and the fifth flow channel 5 is determined in accordance with the position of the discharge port 12b. In the present modification example as well, the suction port 32c, the delivery port 31c, and the discharge port 12b are disposed at positions different from each other when viewed in the axial direction of the pump apparatus 10.

As another flow channel, for example, the pump apparatus 10 may further have a flow channel provided between the outer circumferential surface of the shaft 41 and the inner circumferential surface of the rotor 40. In addition, for example, a penetration hole (not illustrated) may be provided in the rotor 40, and the penetration hole may be used as a flow channel. An oil can more efficiently flow into the motor section 20 and the motor section 20 can be cooled with high efficiency by including another flow channel in addition to the first flow channel 1 to the fifth flow channel 5.

MODIFICATION EXAMPLE OF SECOND FLOW CHANNEL

In the example illustrated in FIG. 3, the second flow channel 2 is a flow channel leading to the inside of the motor section 20 via the first opening portion 31d and the second opening portion 31e of the delivery port 31c. However, a constitution having no delivery port 31c illustrated in FIG. 3 can be employed. In this case, a clearance between the shaft 41 and the pump body 31 in the axial direction is used as a delivery port.

In detail, as illustrated in FIG. 3, the pump body 31 is open at both ends in the axial direction to allow the shaft 41 to pass therethrough and has the penetration hole 31a in which the opening on the front side is open in the pump chamber 33. The penetration hole 31a functions as a bearing member which rotatably supports the shaft 41. Here, the penetration hole 31a provided in the pump body 31, that is, the clearance between the shaft 41 and the pump body 31 in the axial direction is used as a delivery port. In this case, an oil which has been suctioned into the pump section 30 passes through a space between the shaft 41 and the pump body 31. That is, the second flow channel 2 is positioned between the shaft 41 and the pump body 31.

When a space between the shaft 41 and the pump body 31 serves as the second flow channel 2, there is no need to separately provide the delivery port 31c, and it is easy to perform machining. In addition, an oil flowing from the pump section 30 can be used as a lubricant, and the oil can be efficiently delivered to the inside of the motor section 20. A cut-out portion may be provided on at least one of the outer circumferential surface of the shaft or the inner circumferential surface of the pump body 31. Accordingly, flow channel resistance is reduced when the second flow channel 2 passes through a space between the shaft 41 and the pump body 31, and an oil can be more efficiently delivered to the motor section 20 from the pump section 30.

In the present example embodiment, a case where the pump body 31 has a slide bearing structure has been described. However, for example, the pump body 31 may use any bearing as a bearing member. Hereinafter, a case where the pump body 31 has a bearing will be described using FIG. 6.

In the example illustrated in FIG. 6, the shaft 41 is rotatably supported in the direction around the central axis J by a first bearing 34 and a second bearing 80. Similar to the case described above, an oil which has been suctioned into the pump section 30 can be delivered to the motor section 20 by using the clearance between the shaft 41 and the pump body 31 in the axial direction as a delivery port. An oil which has been suctioned into the pump section 30 passes through a space between the shaft 41 and the pump body 31. In this case, the second flow channel passes through a space between the pump body 31 and the shaft 41 and at least any part of a second flow channel 2a to a second flow channel 2c.

The second flow channel 2a is positioned between the shaft 41 and the first bearing 34. The second flow channel 2b is a flow channel passing through the inside of the first bearing 34. For example, when the first bearing 34 is a ball bearing having a plurality of balls, the second flow channel 2b is positioned between balls adjacent to each other. The second flow channel 2c is positioned between the first bearing 34 and the pump body 31.

Similar to the case of a slide bearing, in the second flow channels 2a to 2c, a cut-out portion or a penetration hole may be provided in at least any of the first bearing 34, the pump body 31, and the shaft 41. Accordingly, flow channel resistance of the second flow channels 2a to 2c is reduced, and an oil can be more efficiently delivered to the motor section 20 from the pump section 30.

In addition, the position of the first bearing 34 is not limited to the position illustrated in FIG. 6. The first bearing 34 can be disposed at an arbitrary position between a front end surface and a rear end surface of the pump body 31. For example, in the example illustrated in FIG. 7, in the first bearing 34, the front end surface (pump side one end) of the first bearing 34 in the axial direction is on the rear side, that is, the motor section side of the front end surface (pump side one end) of the pump body 31.

In the example illustrated in FIG. 6, the front end surface of the first bearing 34 is at the same position as the front end surface of the pump body 31 in the axial direction. Therefore, an oil which has been delivered to the motor section 20 from the pump section 30 flows in from the second flow channel 2a, the second flow channel 2b, and the second flow channel 2c and passes through the clearance between the shaft 41 and the pump body 31 in the axial direction. In contrast, in the example illustrated in FIG. 7, an oil which has been delivered to the motor section 20 from the pump section 30 in the second flow channel passes through the clearance between the shaft 41 and the pump body 31 in the axial direction before reaching the first bearing 34.

Here, since the pump body 31 has a holding portion which directly holds the shaft 41, the clearance between the shaft 41 and the pump body 31 in the axial direction is smaller than the clearance between the shaft 41 and the pump body 31 in the axial direction illustrated in FIG. 6. Therefore, an oil can be prevented from being delivered to the motor section 20 from the pump section 30, and degradation of the pump efficiency can be prevented.

MODIFICATION EXAMPLE OF FIFTH FLOW CHANNEL

In the example illustrated in FIG. 3 or 5, the fifth flow channel 5 is a flow channel leading to the outside of the pump apparatus 10 through the discharge port 12b. However, a constitution having no discharge port 12b illustrated in FIG. 3 or 5 can be employed. In this case, a clearance between the shaft 41 and the housing 12 in the axial direction is used as a discharge port.

In detail, as illustrated in FIG. 6, the shaft 41 is rotatably supported in the direction around the central axis J by the first bearing 34 and the second bearing 80. The second bearing 80 is held in the bottom portion of the housing 12. The rear end portion of the shaft 41 penetrates the bottom portion of the housing 12 and protrudes to the outside of the housing 12. Here, a penetration hole which is provided in the housing 12 and is penetrated by the shaft, that is, the clearance between the shaft 41 and the housing 12 in the axial direction is used as a discharge port.

In this case, an oil inside the motor section 20 passes through a space between the shaft 41 and the housing 12. That is, the fifth flow channel passes through a space between the shaft 41 and the housing 12 and at least any part of a fifth flow channel 5a to a fifth flow channel 5c. In order to easily discharge an oil inside the motor section 20 by increasing the clearance between the shaft 41 and the housing 12 in the axial direction, for example, as illustrated in FIG. 7, a penetration hole 12c penetrated by the shaft 41 provided in the housing 12 may be increased in diameter.

The fifth flow channel 5a is positioned between the shaft 41 and the second bearing 80. The fifth flow channel 5b is a flow channel passing through the inside of the second bearing 80. For example, when the second bearing 80 is a ball bearing having a plurality of balls, the fifth flow channel 5b is positioned between balls adjacent to each other. The fifth flow channel 5c is positioned between the second bearing 80 and the housing 12.

Similar to the cases of the second flow channels 2a to 2c which are modification examples of the second flow channel, in the fifth flow channels 5a to 5c, a cut-out portion or a penetration hole may be provided in at least any of the second bearing 80, a part of the housing 12 holding the second bearing 80, and the shaft 41. Accordingly, flow channel resistance of the fifth flow channels 5a to 5c is reduced, and an oil inside the motor section 20 portion can be more efficiently discharged. In addition, in place of the second bearing 80, the motor section 20 may have a slide bearing structure. In this case, the fifth flow channel is positioned between a bearing member (not illustrated) and the shaft 41.

[Second Example Embodiment]

Next, a pump apparatus according to a second example embodiment of the present invention will be described. In the first example embodiment, the motor section has a constitution of an inner rotor motor in which a stator is positioned on the outer side of a rotor in the radial direction. In contrast, a motor section in the present example embodiment has a constitution of an axial gap motor in which a stator is disposed to face a rotor in the axial direction. Hereinafter, the difference between the present example embodiment and the first example embodiment will be mainly described. In the pump apparatus according to the present example embodiment, the same reference signs will be applied to the same constitutions as the pump apparatus according to the first example embodiment, and description thereof will be omitted.

FIG. 8 is a cross-sectional view illustrating a pump apparatus 101 of the present example embodiment.

As illustrated in FIG. 8, the pump apparatus 101 has the shaft 41, a motor section 201, a housing 141, and a pump section 300. The motor section 201 has the shaft 41 rotatably supported about the central axis J extending in the axial direction. The motor section 201 and the pump section 300 are provided side by side in the axial direction.

The motor section 201 has a rotor 402, a stator 501, an upper bearing member 421, a lower bearing member 422, a control device (not illustrated), a bus bar assembly (not illustrated), and a connector (not illustrated). The rotor 402 has a disk shape extending in the radial direction. The rotor 402 has a plurality of magnets 442 which are arranged in the circumferential direction on a surface (positive Z-side surface) facing the stator 501, and a rotor yoke 432 which holds the magnets 442. That is, the magnets 442 is disposed to face the rear end portion of the stator 501 in the axial direction. The rotor yoke 432 is fixed to the outer circumferential surface of the shaft 41.

The upper bearing member 421 and the lower bearing member 422 rotatably support the shaft 41. The upper bearing member 421 and the lower bearing member 422 are fixed to a bearing housing 630. The stator 501 has a plurality of cores which have a fan shape in a plan view and are arranged in the circumferential direction, coils which are provided in the cores, and coil leader lines which lead from the coils of the cores. In addition, the stator 501 has a mold resin which firmly fixes the plurality of cores in an integrated manner, and a plurality of leader line support portions which are provided at an outer circumferential end of the stator 501.

The housing 141 constitutes a casing of the motor section 201. The control device (not illustrated) and the bus bar assembly (not illustrated) may be accommodated on the rear side (negative Z-side) of the stator 501. The rotor 402 is accommodated on the rear side (negative Z-side) of the stator 501. The housing 141 has a first housing 121 which has a covered cylindrical shape and of which the rear side is open, and a second housing (cover) 131 which has a bottomed cylindrical shape and is coupled to the rear side (negative Z-side) of the first housing 121. The material of the housing 141 is a metal or a resin, for example.

The first housing 121 has a top wall 121a having a disk shape, and the shaft 41 passes through a central portion of the top wall 121a. The bearing housing 630 is fitted into the opening portion of the pump section 300 on the rear side. The bearing housing 630 holds the upper bearing member 421 and the lower bearing member 422.

The second housing 131 has a bottom wall 131a which has a disk shape, and a cover cylinder portion 131b which extends from a circumferential edge portion of the bottom wall 131a to the front side (positive Z-side). The positions of the upper bearing member 421 and the lower bearing member 422 are not limited to the positions illustrated in FIG. 8 and can be changed. For example, the upper bearing member 421 may be included in the pump section 300 instead of the motor section 201.

The cover cylinder portion 131b is fixed to the opening portion of the first housing 121 on the rear side (negative Z-side). In more detail, the first housing 121 and the second housing 131 are fixed by a method such as bolt fastening using flange portions 111 and 112 of the second housing 131 and flange portions 113 and 114 of the first housing 121.

When the control device (not illustrated) and the bus bar assembly (not illustrated) are accommodated in the second housing 131, a penetration hole (not illustrated) penetrating the bottom wall 131a in the axial direction is provided in the bottom wall 131a of the second housing 131, and a connector (not illustrated) is attached to the penetration hole. An external connection terminal (not illustrated) penetrating the bottom wall 131a from the bus bar assembly and extending to the rear side (negative Z-side) is disposed in the connector.

The housing 141 has a discharge port 131c. The discharge port 131c discharges an oil, which has been suctioned by the pump section 300 (which will be described below) through a suction port 321c and has been delivered to the motor section 201 through a delivery port 311c, to the outside of the pump apparatus 101. In the example illustrated in FIG. 8, the discharge port 131c is provided in the bottom portion of the housing 141. In detail, the discharge port 131c is provided in the bottom wall 131a of the second housing 131.

In addition, in the present example embodiment, the discharge port 131c is positioned on the outer side of the stator 501 in the radial direction when viewed in the axial direction. The reason is as follows. When the stator 501 is fixed to the shaft in the pump apparatus 101 having a constitution of an axial gap motor, the following can be realized by including the discharge port 131c at the position described above. That is, in the motor section 201, since an oil which has flowed to the third flow channel 3 is discharged at the shortest distance without passing through an unnecessary flow channel, an oil inside the motor section 201 can be efficiently discharged.

The position of the discharge port 131c is not limited to the position illustrated in FIG. 8. The discharge port 131c may be provided at an arbitrary position in the housing 141. For example, the discharge port 131c may be provided on the side surface of the housing 141. For example, the discharge port 131c may be provided between one end of the stator 501 on a side opposite to the pump section 300 in the axial direction and the bottom wall 131a of the second housing 131, in a tube portion 121b of the first housing 121 or the cover cylinder portion 131b of the second housing 131.

In addition, an optimal position can be selected as the position of the discharge port 131c in accordance with the position of the pump apparatus 101 inside an external apparatus to which the pump apparatus 101 is attached. For example, similar to the case of the first example embodiment, when the pump apparatus 101 is disposed such that the axial direction extends horizontally, and when the pump apparatus 101 is disposed such that the negative side in the X-axis direction (negative X-side) becomes the upper side and the positive side in the X-axis direction (positive X-side) becomes the lower side with respect to the shaft 41, the discharge port 131c may be provided at a position above the shaft 41 in the direction of gravity.

That is, when the pump apparatus 101 is disposed such that the direction of gravity becomes the positive X-direction in FIG. 8, and when the negative X-side becomes the upper side and the positive X-side becomes the lower side with respect to the shaft 41, the discharge port 131c is provided at a position symmetrical about the shaft 41 with respect to the discharge port 131c illustrated in FIG. 8. The reason for this is that a hot oil can be discharged from the motor section 201 with priority by providing the discharge port 131c on the upper side in the direction of gravity.

In addition, the number of discharge ports 131c to be provided is not limited to one, and a plurality of discharge ports 131c may be provided. When a plurality of discharge ports 131c are provided, each of the discharge ports 131c may be provided at an arbitrary position on the side surface or in the bottom portion of the housing 141 as described above. In addition, the discharge ports 131c may be individually provided on both the side surface and the bottom portion of the housing. An oil inside the motor section 201 can be more efficiently discharged by providing a plurality of discharge ports 131c.

The pump section 300 is positioned on one side of the motor section 201 in the axial direction, in detail, on the front side (positive Z-axis side). The pump section 300 is driven by the motor section 201 and the shaft 41. The pump section 300 has a pump body 311, a pump rotor 351, and a pump cover 321. The pump rotor 351 has an inner rotor 371 and an outer rotor 381.

Similar to the first example embodiment, the pump section 300 is a positive-displacement pump and is a trochoid pump in the present example embodiment. The pump section 300 is not limited to a trochoid pump, and a pump of any type may be adopted as long as the pump is a positive-displacement pump. Since description for each member of the pump section 300 is similar to that in the first example embodiment, it will be omitted. Since the structure of the pump section 300 is similar to that in the first example embodiment, description thereof will be omitted.

The pump section 300 has the suction port 321c and the delivery port 311c. Hereinafter, details of the suction port 321c and the delivery port 311c will be described. The suction port 321c is provided in the pump cover 321. In detail, the suction port 321c is open at both ends of the pump cover 321 in the axial direction and has a cylindrical shape extending in the axial direction. The opening portion of the suction port 321c on the rear side is connected to the negative pressure region of a pump chamber 331. Since an oil is suctioned through the suction port 321c due to a negative pressure in the pump section 300, an oil can be efficiently suctioned when the suction port 321c is connected to the negative pressure region.

The position of the suction port 321c is not limited to the position illustrated in FIG. 8. The suction port 321c may be provided at an arbitrary position in the pump cover 321 and may be provided in the pump body 311. Similar to the first example embodiment, an optimal position can be selected as the position of the suction port 321c in accordance with the position inside the external apparatus to which the pump apparatus 101 is attached.

For example, the suction port 321c may be provided in a side surface portion 321a of the pump cover 321 in accordance with the position of an oil pan (not illustrated) serving as a supply source of an oil. When the suction port 321c is provided in the side surface portion 321a of the pump cover 321, the suction port 321c is open in the pump cover 321 and is open on the side surface of the pump body 311. In detail, the suction port 321c can be easily connected to the negative pressure region of the pump chamber 331 by providing the suction port 321c in the wall portion of the pump body 311 and the side surface portion 321a of the pump cover 321 circumscribing the wall portion.

The delivery port 311c is provided in the pump body 311. In detail, the delivery port 311c is open at both ends of the pump body 311 in the axial direction and has a cylindrical shape extending in the axial direction. The opening portion of the delivery port 311c on the front side is provided on a surface of the pump body 311 facing a top wall 321b of the pump cover 321 and is connected to the pressurization region of the pump chamber 331. Since an oil which has been suctioned into the pump chamber 331 through the suction port 321c is delivered to the motor section 201 due to pressurization of the pump section 300, an oil can be efficiently delivered when the delivery port 311c is connected to the pressurization region.

In the present example embodiment, since the first housing 121 of the motor section 201 has the top wall 121a, an opening portion is also provided in a part connected to the opening portion of the delivery port 311c on the rear side in the top wall 121a of the first housing 121.

The position of the delivery port 311c is not limited to the position illustrated in FIG. 8. The delivery port 311c may be provided at an arbitrary position in the pump body 311 as long as the delivery port 311c can be connected to the pressurization region of the pump chamber 331 at the position. For example, when the pump apparatus 101 is disposed such that the axial direction extends horizontally, the delivery port 311c may be provided at a position below the shaft 41 in the direction of gravity.

That is, when the pump apparatus 101 is disposed such that the direction of gravity becomes the negative X-direction FIG. 8, and when the positive X-side becomes the upper side and the negative X-side becomes the lower side with respect to the shaft 41, the delivery port 311c is provided at a position symmetrical about the shaft 41 with respect to the delivery port 311c illustrated in FIG. 8. The reason for this is that a cold oil can be delivered to the motor section 201 with priority by providing the delivery port 311c on the lower side in the direction of gravity.

In the present example embodiment as well, the suction port 321c and the delivery port 311c are disposed at positions different from each other in the circumferential direction with reference to the central axis J. Accordingly, the suction port 321c can be disposed on the negative pressure region side and the delivery port 311c can be disposed on the pressurization region side. Therefore, as described above, an oil can be efficiently suctioned into the pump section 300 and can be delivered to the motor section 201.

In addition, in FIG. 8, the suction port 321c, the delivery port 311c, and the discharge port 131c are disposed at positions different from each other when viewed in the axial direction of the pump apparatus 101. Moreover, a cross-sectional area of the delivery port 311c is smaller than a cross-sectional area of the discharge port 131c. The cross-sectional area of the delivery port 311c indicates the opening area at the narrowest place in the opening of the delivery port 311c extending in the axial direction. Similarly, the cross-sectional area of the discharge port 131c indicates the opening area at the narrowest place in the opening of the discharge port 131c extending in the axial direction.

The cross-sectional area of the delivery port 311c may be larger than the cross-sectional area of the discharge port 131c. In this case, the discharge pressure from the inside of the motor section 201 to the outside of the motor section 201 can be further improved than the discharge pressure from the pump section 300 to the inside of the motor section 201.

Next, a cooling structure of the pump apparatus 101 according to the present example embodiment will be described. In the present example embodiment, an oil which has been supplied to the pump chamber 331 through the suction port 321c of the pump section 300 is delivered to the motor section 201 through the delivery port 311c by the pump rotor 351. The oil cools the stator 501 and the rotor 402 at the same time by circulating inside the motor section 201 and is discharged to the external apparatus via the discharge port 131c of the motor section 201. Hereinafter, flow channels for an oil in the pump apparatus 101 will be described mainly regarding the difference between the present example embodiment and the first example embodiment.

As illustrated in FIG. 8, the pump apparatus 101 has the first flow channel 1 for suctioning an oil into the pump section 300 through the suction port 321c of the pump section 300 using a negative pressure in the pump section 300, the second flow channel 2 for delivering an oil to the inside of the motor section 201 through the delivery port 311c of the pump section 300 using pressurization of the pump section 300, the third flow channel 3 provided between the stator 501 and the rotor 402, the fourth flow channel 4 provided between the stator 501 and the housing 141, and the fifth flow channel 5 for discharging an oil inside the motor section 201 through the discharge port 131c of the motor section 201. Hereinafter, details of each flow channel will be described.

Since the first flow channel 1, the second flow channel 2, and the fourth flow channel 4 of the present example embodiment are similar to those in the first example embodiment, description thereof will be omitted. The third flow channel 3 is positioned between the rear end surface of the stator 501 in the axial direction and the front end surface of the rotor 402 in the axial direction. In detail, an oil which has flowed into the motor section 201 via the second flow channel 2 is divided into an oil flowing to the third flow channel 3 and an oil flowing to the fourth flow channel 4. An oil flowing into the third flow channel passes through a space between the coils of the stator 501 first and flows between the rear end surface of the stator 501 in the axial direction and the front end surface of the rotor 402 in the axial direction thereafter.

The oil which has flowed to the fourth flow channel 4 flows to one end on the rear side from one end on the front side of the fourth flow channel 4. Since the surface area of the stator 501 which comes into contact with an oil can be increased by providing the fourth flow channel 4, the inside of the motor section 201 can be more efficiently cooled.

The fifth flow channel in FIG. 8 is provided in the bottom portion of the housing 141 and leads to the outside of the pump apparatus 101 through the discharge port 131c. The fifth flow channel 5 varies depending on the position of the discharge port 131c. The position of the discharge port 131c is not limited to the position illustrated in FIG. 8. As described above, the discharge port 131c can be provided at an arbitrary position on the side surface of the housing 141 and in the bottom portion of the housing 141.

An oil which has flowed to the fourth flow channel 4 merges with an oil from the third flow channel 3 and flows to the fifth flow channel 5. In the present example embodiment as well, an oil which has been discharged to the outside of the pump apparatus 101 from the fifth flow channel 5 is discharged to the CVT through the discharge port of the transmission case in which the pump apparatus 101 is built.

Similar to the first example embodiment, the fourth flow channel 4 may have a cut-out portion (not illustrated) on the outer circumferential surface of the stator 501 or an inner circumferential surface 6 of the housing 141. When the stator 501 has a cut-out portion, the surface area of the stator 501 which comes into contact with an oil can be increased. Therefore, the inside of the motor section 201 can be more efficiently cooled. In addition, when the stator 501 has a cut-out portion, or when the housing 141 has a cut-out portion, the flow rate of an oil flowing to the fourth flow channel 4 can be increased. Therefore, an oil can more efficiently circulate.

In addition, similar to the first example embodiment, the stator 501 and the rotor 402 may be integrally molded products formed of a resin. When the stator 501 or the rotor 402 is an integrally molded product formed of a resin, the surface area of the stator or the rotor which comes into contact with an oil is increased. Therefore, the inside of the motor section 201 can be more efficiently cooled.

According to the present example embodiment, the pump apparatus 101 has the motor section 201 that has the shaft 41 rotatably supported about the central axis J extending in the axial direction; and the pump section 300 that is positioned on one side of the motor section 201 in the axial direction, is driven by the shaft 41 extending from the motor section 201, suctions an oil, and delivers the oil to the motor section 201. The motor section 201 has the rotor 402 rotating around the shaft 41, the stator 501 disposed to face the rotor 402, the housing 141 accommodating the rotor 402 and the stator 501, and the discharge port 131c provided in the housing 141 to discharge an oil. The pump section 300 has the pump rotor 351 attached to the shaft 41, the pump case accommodating the pump rotor 351, the suction port 321c provided in the pump case to suction an oil, and the delivery port 311c provided in the pump case to deliver an oil to the motor section 201. In the pump apparatus 101, the suction port 321c, the delivery port 311c, and the discharge port 131c are disposed at positions different from each other when viewed in the axial direction. The pump apparatus 101 has the first flow channel 1 for suctioning an oil into the pump section 300 through the suction port 321c of the pump section 300 using a negative pressure in the pump section 300, the second flow channel 2 for delivering an oil to the inside of the motor section 201 through the delivery port 311c of the pump section 300 using pressurization of the pump section 300, the third flow channel 3 provided between the stator 501 and the rotor 402, the fourth flow channel 4 provided between the stator 501 and the housing 141, and the fifth flow channel 5 for discharging an oil inside the motor section 201 through the discharge port 312c.

According to the present example embodiment, an oil which has been suctioned into the pump section 300 through the suction port 321c due to a negative pressure in the pump section 300 and has been delivered to the motor section 201 through the delivery port 311c due to pressurization of the pump section 300 flows inside the motor section 201. Accordingly, the oil cools the stator 501 and the rotor 402 at the same time. In the present example embodiment, an oil which has been suctioned into the pump section 300 is not divided into an oil to be discharged to the external apparatus and an oil for cooling the motor section 201, and an oil which has been suctioned into the pump section 300 is delivered to the motor section 201. Therefore, cooling of the stator 501 and the rotor 402 can be realized at the same time without having the pump efficiency being degraded. In addition, according to the present example embodiment, in the pump apparatus 101, the stator 501 can be cooled from both the housing 141 side and the rotor 402 side by including the third flow channel 3 and the fourth flow channel 4. Therefore, the stator 501 can be efficiently cooled. That is, it is possible to provide a structure having a high cooling effect for curbing temperature rise in the motor section 201.

In the pump apparatus 101 of the present example embodiment, a case where the stator 501 is fixed to the bearing housing 630 has been described. However, the constitution is not limited thereto. For example, even when the stator 501 of the pump apparatus 101 is fixed to the housing 141, the present invention can be applied.

In addition, similar to the case of the first example embodiment, a constitution having no delivery port 311c can be employed, and the second flow channel 2 is positioned between the shaft 41 and the pump body 311. At this time, in the second flow channel 2, an oil passes through at least any part between the shaft 41 and the upper bearing member 421, in the upper bearing member 421, and between the upper bearing member 421 and the pump body 311.

In addition, when the shaft 41 penetrates the bottom wall 131a of the second housing 131 and protrudes to the rear side, a constitution having no discharge port 131c can be employed. In this case, the fifth flow channel 5 is positioned between the shaft 41 and the bottom wall 131a of the second housing 131. In the fifth flow channel 5, an oil passes through at least any part between the shaft 41 and the lower bearing member 422, in the lower bearing member 422, and between the lower bearing member 422 and a lower bearing holding portion 652 provided in the bottom wall 131a.

In addition, in the present example embodiment, a case where the motor section 201 of the pump apparatus 101 has only the rotor 402 has been described. However, the constitution is not limited thereto. For example, the motor section 201 may have two rotors. For example, two rotors may be attached to the shaft 41 at a predetermined interval in the axial direction and the stator 501 may be disposed between the two rotors. The present invention can be applied to the foregoing constitution having two rotors.

Hereinabove, example embodiments of the present invention have been described. However, the present invention is not limited to these example embodiments, and various modifications and changes can be made within a range of the gist thereof.

While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.

PUMP APPARATUS

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