WO2018159480A1

WO2018159480A1 - Electric oil pump

Info

Publication number: WO2018159480A1
Application number: PCT/JP2018/006647
Authority: WO
Inventors: 小林　喜幸; 貴光江藤; 慈裕片岡; 弘貴金物
Original assignee: 日本電産トーソク株式会社
Priority date: 2017-03-03
Filing date: 2018-02-23
Publication date: 2018-09-07
Also published as: CN211082246U; US20190376511A1; JPWO2018159480A1

Abstract

This electric oil pump 10 comprises a motor unit 20, a pump unit 30, and a motor drive unit 60. The pump unit 30 comprises a pump rotor 35 attached to a shaft 41, a pump body 31, and a pump cover 32. The motor drive unit 60 comprises an inverter circuit 65 which controls driving of the motor, and an inverter cover 63. The inverter circuit 65 is in thermal contact with the pump cover 32.

Description

Electric oil pump

The present invention relates to an electric oil pump.

In recent years, CVT (Continuously Variable Transmission), DCT (Dual Clutch Transmission), etc. are known as transmissions for automobiles and the like. These transmissions have been studied in various shapes for the purpose of improving fuel efficiency.
In addition, a transmission is required to have a function of supplying oil using a motor when idling is stopped, and an electric oil pump having an inverter circuit, a motor and a pump is required to realize this function. Yes.
For example, Patent Literature 1 discloses an electric oil pump having a structure in which a pump cover portion in which an inverter circuit is accommodated is part of a transmission case.

Japanese Patent Laying-Open No. 2015-175291

However, since the electric oil pump disclosed in Patent Document 1 has a pump cover that also serves as a part of the transmission case, the structure of the electric oil pump is limited by the structure of the transmission. For this reason, in various transmissions, an electric oil pump having a structure having an inverter circuit, a motor, and a pump cannot be used for general purposes.
Further, in the electric oil pump, when higher output is demanded from the viewpoint of responsiveness and the like, the amount of heat generated by the elements used in the inverter circuit increases, so that the inverter circuit needs to be cooled efficiently.

An object of the present invention is to provide an electric oil pump that can efficiently cool an inverter circuit and can be used for various purposes in various transmissions.

An electric oil pump according to an exemplary first invention of the present application includes a motor unit having a shaft rotatably supported around a central axis extending in an axial direction, and the motor unit located on one axial side of the motor unit. A pump part that is driven by the shaft extending from the part and discharges oil; and a motor drive part that is located on one side in the axial direction of the motor part and drives the motor part via the pump part. The motor unit includes a rotor that is rotatable around the shaft, a stator that is disposed radially outside the rotor, and a housing that houses the rotor and the stator, and the pump unit includes: A pump rotor attached to the shaft; a recess containing the pump rotor and including a side wall surface and a bottom surface located on the other axial side of the motor portion; A pump body having an opening on the one axial side of the motor unit, and a pump cover for closing the opening, and the motor driving unit is an inverter circuit for controlling the driving of the motor unit; An inverter cover covering the inverter circuit, and the inverter circuit is in thermal contact with the pump cover.

According to the first exemplary invention of the present application, it is possible to provide an electric oil pump that can efficiently cool an inverter circuit and can be used for various purposes in various transmissions.

It is sectional drawing which shows the electric oil pump which concerns on 1st Embodiment. It is sectional drawing which shows the 1st modification of a motor drive part. It is sectional drawing which shows the 2nd modification of a motor drive part. It is sectional drawing which shows the 3rd modification of a motor drive part. It is sectional drawing which shows the 4th modification of a motor drive part. It is sectional drawing which shows the 5th modification of a motor drive part. It is sectional drawing which shows the 6th modification of a motor drive part. It is sectional drawing which shows the 7th modification of a motor drive part. It is sectional drawing which shows the electric oil pump which concerns on 2nd Embodiment. It is sectional drawing which shows the electric oil pump which concerns on 3rd Embodiment. It is sectional drawing which shows the electric oil pump which concerns on 4th Embodiment.

Hereinafter, an electric oil pump according to an embodiment of the present invention will be described with reference to the drawings. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale and number in each structure.

In the drawings, an XYZ coordinate system is appropriately shown as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the central axis J shown in FIG. The X-axis direction is a direction parallel to the direction in which the top plate portion 63a of the inverter cover 63 shown in FIG. 1 extends, that is, the left-right direction in FIG. The Y-axis direction is a direction orthogonal to both the X-axis direction and the Z-axis direction.

In the following description, the positive side (+ Z side) in the Z-axis direction is referred to as “front side”, and the negative side (−Z side) in the Z-axis direction is referred to as “rear side”. The rear side and the front side are names used for explanation only, and do not limit the actual positional relationship and direction. Unless otherwise specified, a direction parallel to the central axis J (Z-axis direction) is simply referred to as an “axial direction”, and a radial direction around the central axis J is simply referred to as a “radial direction”. The circumferential direction centered at, that is, around the central axis J (θ direction) is simply referred to as “circumferential direction”.

In addition, in this specification, “thermally contacting” includes not only a case where target members are in direct contact with each other but also a case where a member involved in heat conduction is interposed between the members. Further, in this specification, “extending in the axial direction” means not only extending in the axial direction (Z-axis direction) but also extending in a direction inclined by less than 45 ° with respect to the axial direction. Including. Further, in this specification, “extending in the radial direction” means that 45% with respect to the radial direction, in addition to the case where it extends strictly in the radial direction, that is, the direction perpendicular to the axial direction (Z-axis direction). This includes cases extending in a tilted direction within a range of less than °.

[First Embodiment]
<Overall configuration>
FIG. 1 is a cross-sectional view showing the electric oil pump of the present embodiment.
The electric oil pump 10 of this embodiment includes a motor unit 20, a pump unit 30, and a motor driving unit 60. The motor unit 20, the pump unit 30, and the motor driving unit 60 are provided side by side along the axial direction.
The motor unit 20 has a shaft 41 supported so as to be rotatable about a central axis J extending in the axial direction, and drives the pump by rotating the shaft 41. The pump unit 30 is located on the front side (+ Z side) of the motor unit 20 and is driven by the motor unit 20 via the shaft 41 to discharge oil. The motor driving unit 60 is located on the front side (+ Z side) of the pump unit 30 and controls driving of the motor unit 20.
Hereinafter, each constituent member will be described in detail.

<Motor unit 20>
As shown in FIG. 1, the motor unit 20 includes a housing 21, a rotor 40, a shaft 41, a stator 50, and a bearing 55.

The motor unit 20 is, for example, an inner rotor type motor, in which the rotor 40 is fixed to the outer peripheral surface of the shaft 41 and the stator 50 is positioned on the radially outer side of the rotor 40. The bearing 55 is disposed at the axial rear end (−Z side) end portion of the shaft 41 and supports the shaft 41 rotatably.

(Housing 21)
As shown in FIG. 1, the housing 21 has a bottomed thin cylindrical shape, and includes a bottom surface portion 21a, a stator holding portion 21b, a pump body holding portion 21c, a side wall portion 21d,

flange portions

24 and 25, Have The bottom surface portion 21a forms a bottomed portion, and the stator holding portion 21b, the pump body holding portion 21c, and the side wall portion 21d form a cylindrical side wall surface centered on the central axis J. In the present embodiment, the inner diameter of the stator holding portion 21b is larger than the inner diameter of the pump body holding portion 21c. The outer surface of the stator 50, that is, the outer surface of the core back portion 51 described later is fitted to the inner surface of the stator holding portion 21 b. Thereby, the stator 50 is accommodated in the housing 21. The flange portion 24 extends radially outward from the front side (+ Z side) end portion of the side wall portion 21d. On the other hand, the flange portion 25 extends radially outward from the rear side (−Z side) end portion of the stator holding portion 21b. The flange portion 24 and the flange portion 25 face each other and are fastened by fastening means (not shown). Thereby, the motor unit 20 and the pump unit 30 are sealed and fixed in the housing 21.
As the material of the housing 21, for example, a zinc-aluminum-magnesium alloy or the like can be used, and specifically, a hot-dip zinc-aluminum-magnesium alloy plated steel plate and a steel strip can be used. Further, the bottom surface portion 21 a is provided with a bearing holding portion 56 for holding the bearing 55.

(Rotor 40)
The rotor 40 includes a rotor core 43 and a rotor magnet 44. The rotor core 43 is fixed to the shaft 41 so as to surround the shaft 41 around the axis (θ direction). The rotor magnet 44 is fixed to the outer surface along the axis of the rotor core 43 (θ direction). The rotor core 43 and the rotor magnet 44 rotate together with the shaft 41.

(Stator 50)
The stator 50 surrounds the rotor 40 around the axis (θ direction), and rotates the rotor 40 around the central axis J. The stator 50 includes a core back part 51, a tooth part 52, a coil 53, and a bobbin (insulator) 54.

The shape of the core back portion 51 is a cylindrical shape concentric with the shaft 41. The teeth part 52 extends from the inner surface of the core back part 51 toward the shaft 41. A plurality of teeth portions 52 are provided, and are arranged at equal intervals in the circumferential direction of the inner side surface of the core back portion 51. The coil 53 is provided around a bobbin (insulator) 54 and is formed by winding a conductive wire 53a. A bobbin (insulator) 54 is attached to each tooth portion 52.

(Bearing 55)
The bearing 55 is disposed on the rear side (−Z side) of the rotor 40 and the stator 50 and is held by the bearing holding portion 56. The bearing 55 supports the shaft 41. The shape, structure, and the like of the bearing 55 are not particularly limited, and any known bearing can be used.

<Pump unit 30>
The pump unit 30 is provided on one side in the axial direction of the motor unit 20, specifically on the front side (+ Z axis side). The pump unit 30 has the same rotating shaft as the motor unit 20 and is driven by the motor unit 20 via the shaft 41. The pump unit 30 includes a positive displacement pump that pumps oil by expanding and reducing the volume of a sealed space (oil chamber). As the positive displacement pump, for example, a trochoid pump is used. The pump unit 30 includes a pump body 31, a pump cover 32, and a pump rotor 35. Hereinafter, the pump body 31 and the pump cover 32 are also referred to as a pump case.

(Pump body 31)
The pump body 31 is located on the front side (+ Z axis side) of the motor unit 20. The pump body 31 has a cylindrical shape from the pump body main body 31b, a through hole 31a penetrating the inside of the pump body main body 31b along the axial direction of the central axis J, and from the pump body main body 31b to the front side (+ Z axis side). And a protruding portion 31c that protrudes. The inner diameter of the protrusion 31c is larger than the inner diameter of the through hole 31a. The protrusion 31c and the pump body main body 31b form a recess 33 that opens to the pump cover 32 side. The through hole 31a opens to the motor unit 20 side on the rear side (−Z side), and opens to the recess 33 on the front side (+ Z axis side). The through hole 31a functions as a bearing member into which the shaft 41 is inserted and rotatably supports the shaft 41. The recess 33 accommodates the pump rotor 35 and functions as a pump chamber (hereinafter also referred to as the pump chamber 33).

The pump body 31 is fixed in the pump body holding part 21c on the front side (+ Z axis side) of the motor part 20. An O-ring 71 is provided between the outer peripheral surface of the pump body main body 31b and the inner peripheral surface of the pump body holding portion 21c. Thereby, a gap between the outer peripheral surface of the pump body 31 and the inner peripheral surface of the housing 21 is sealed.

As the material of the pump body 31, for example, cast iron or the like can be used.

(Pump rotor 35)
The pump rotor 35 is attached to the front side (+ Z axis side) end of the shaft 41 and is accommodated in the pump chamber 33. The pump rotor 35 includes an inner rotor 37 attached to the shaft 41 and an outer rotor 38 surrounding the radially outer side of the inner rotor 37.

The inner rotor 37 is an annular gear having teeth on the radially outer surface. The inner rotor 37 is fixed to the shaft 41 by press-fitting the front side (+ Z axis side) end portion of the shaft 41 into the inner rotor 37. The inner rotor 37 rotates around the axis (θ direction) together with the shaft 41.

The outer rotor 38 is an annular gear that surrounds the radially outer side of the inner rotor 37 and has teeth on the radially inner side surface. The outer rotor 38 is rotatably accommodated in the pump chamber 33. In the outer rotor 38, an inner housing chamber (not shown) for housing the inner rotor 37 is formed in a star shape, for example. The number of inner teeth of the outer rotor 38 is larger than the number of outer teeth of the inner rotor 37.

The inner rotor 37 and the outer rotor 38 mesh with each other, and when the inner rotor 37 is rotated by the shaft 41, the outer rotor 38 is rotated with the rotation of the inner rotor 37. As the inner rotor 37 and the outer rotor 38 rotate, the volume of the space formed between the inner rotor 37 and the outer rotor 38 changes according to the rotational position. The pump rotor 35 uses the volume change to suck oil from a suction port 32c described later, pressurizes the sucked oil, and discharges it from the discharge port 32d. In the present embodiment, in a space formed between the inner rotor 37 and the outer rotor 38, a region where the volume increases (that is, oil is sucked) is defined as a negative pressure region.

(Pump cover 32)
The pump cover 32 is attached to the front side (+ Z axis side) of the pump body 31. The pump cover 32 includes a pump cover body 32a, a flange portion 32b, a suction port 32c, a discharge port 32d, a suction port 32e, and a discharge port 32f.
The pump cover 32 is usually made of a metal such as an aluminum alloy, has a large heat capacity and a large surface area, and therefore has a high heat dissipation effect. Moreover, since the oil below a fixed temperature (for example, 120 degreeC) flows through the inside of the pump cover 32, the temperature rise of the pump cover 32 is suppressed.

The pump cover main body 32a has a disk shape extending in the radial direction. The pump cover main body 32a closes the opening on the front side (+ Z axis side) of the recess 33. The flange portion 32b extends in the radial direction at the outer edge of the front side (+ Z axis side) of the pump cover main body 32a. The outer diameter of the pump cover 32 is larger than the outer diameter of the protruding portion 31c of the pump body 31 due to the flange portion 32b.

The suction port 32c is a crescent-shaped groove when viewed from the pump rotor 35 to the front side (+ Z-axis side). As the volume of the space formed between the inner rotor 37 and the outer rotor 38 increases, the suction port 32c communicates with the pump rotor 35 to the extent that the volume increases. Similarly, the discharge port 32d is a crescent-shaped groove when viewed from the pump rotor 35 on the front side (+ Z axis side). As the volume of the space formed between the inner rotor 37 and the outer rotor 38 decreases, the discharge port 32d communicates with the pump rotor 35 to the extent that the volume decreases.

The suction port 32e extends from the suction port 32c in the pump cover main body 32a toward the -X side (left side in the figure) and communicates with the outside. On the other hand, the discharge port 32f extends from the discharge port 32d in the pump cover main body 32a toward the X side (right side in the figure) and communicates with the outside. The suction port 32e and the discharge port 32f are connected to the pump rotor 35 via the suction port 32c and the discharge port 32d, respectively. As a result, oil can be sucked into the pump rotor 35 and discharged from the pump rotor 35. Specifically, due to the negative pressure generated in the pump chamber by the rotation of the pump rotor 35, oil stored in an oil pan (not shown) is sucked into the pump chamber from the suction port 32e via the suction port 32c. The The sucked oil is discharged from the pressurizing region to the discharge port 32f via the discharge port 32d.

<Motor drive unit 60>
The motor driving unit 60 is provided on the front side (+ Z side) of the pump cover 32 and controls driving of the motor unit 20. The motor drive unit 60 includes an inverter cover 63 and an inverter circuit 65 including a circuit board 61 and a heating element 62.

(Inverter circuit 65)
The inverter circuit 65 has a heating element 62 mounted on a circuit board 61, supplies power for driving to the coil 53 of the stator 50 of the motor unit 20, and drives, rotates and stops the motor unit 20. Control the behavior. In addition, power supply between the motor driving unit 60 and the coil 53 of the stator 50 and communication by an electric signal are performed between the motor driving unit 60 and the coil 53 using a wiring member such as a coated cable (not shown). Done by connecting to.

The circuit board 61 outputs a motor drive signal. In the present embodiment, the circuit board 61 is disposed directly on the surface of the pump cover 32 while ensuring insulation. A printed wiring (not shown) is provided on the surface of the circuit board 61. Further, by using a copper inlay substrate as the circuit substrate 61, the heat generated by the heating element 62 can be easily transmitted to the pump cover 32, and the cooling efficiency is improved.

The heating element 62 is mounted on the front side (+ Z side) surface of the circuit board 61. The heating element 62 is, for example, a capacitor, a microcomputer, a power IC, a field effect transistor (FET), or the like. Further, the number of heating elements 62 is not limited to two, and may be one or three or more.

(Inverter cover 63)
The inverter cover 63 is provided on the front side (+ Z side) of the pump cover 32 and covers the circuit board 61 and the heating element 62. The inverter cover 63 has a top plate portion 63a and a flange portion 63b.

The top plate 63a extends in the radial direction in contact with the front side (+ Z side) surface of the heating element 62. The flange portion 63b extends from the outer edge of the top plate portion 63a to the rear side (−Z side). The rear end surface (−Z side) of the flange portion 63b is in contact with the front side (+ Z side) surface of the flange portion 32b of the pump cover 32. When the heating element 62 of the inverter circuit 65 is in direct contact with the top plate portion 63 a of the inverter cover 63, the heat generated by the heating element 62 can be radiated from the inverter cover 63.

The inverter cover 63 is fixed to the pump cover 32 by fastening the flange portion 63b of the inverter cover 63 and the flange portion 32b of the pump cover 32 with fastening means 64 such as bolts and nuts.

<Operation of this embodiment>
(Operation of electric oil pump)
First, an operation when the electric oil pump 10 is operated will be described.

In the electric oil pump 10 of the present embodiment, first, power is supplied to the motor driving unit 60 from an external power source connected via a connector unit (not shown). As a result, a drive current is supplied from the motor drive unit 60 to the coil 53 of the stator 50 via a wiring member such as a covered cable (not shown). When a drive current is supplied to the coil 53, a magnetic field is generated, and the rotor core 43 and the rotor magnet 44 of the rotor 40 are rotated together with the shaft 41 by the magnetic field. In this way, the electric oil pump 10 obtains a rotational driving force.

The drive current supplied to the coil 53 of the stator 50 is controlled by a power IC and circuit components that are the heating elements 62 of the inverter circuit 65 in the motor drive unit 60. Specifically, the motor drive unit 60 detects the rotational position of the rotor 40 by detecting a change in magnetic flux of a sensor magnet (not shown) by a rotation sensor (not shown). The inverter circuit 65 of the motor drive unit 60 outputs a motor drive signal corresponding to the rotational position of the rotor 40 and controls the drive current supplied to the coil 53 of the stator 50. In this way, the drive of the electric oil pump 10 of this embodiment is controlled.

When electric power is supplied from the motor drive unit 60 to the coil 53, the rotor core 43 and the rotor magnet 44 are rotated by being applied to the coil 53 and generating a rotating magnetic field. The rotation of the rotor 40 is transmitted to the inner rotor 37 of the pump rotor 35 via the shaft 41, and the inner rotor 37 rotates. Thereby, a negative pressure is generated in the pump chamber 33 facing the suction port 32c.

(Oil flow)
Next, the flow of oil will be described. The suction port 32e of the electric oil pump 10 is connected to an oil pan (not shown) in which oil is stored by a flow pipe (not shown), and the oil pan side tip of the flow pipe is immersed in the oil. Due to the negative pressure generated by the rotation of the inner rotor 37 of the electric oil pump 10, the oil stored in the oil pan enters the electric oil pump 10 through the suction port 32e and reaches the suction port 32c. The oil sucked into the pump chamber 33 from the suction port 32c is pumped to the discharge port 32d and discharged from the discharge port 32d to the discharge port 32f. The discharged oil is supplied into a transmission (not shown). The supplied oil generates hydraulic pressure at the relevant location, and then it is refluxed and stored again in the oil pan.

<Effect of this embodiment>
(1) The pump cover 32 is usually made of a metal such as an aluminum alloy, has a large heat capacity and a large surface area, and therefore has a high heat dissipation effect. In the present embodiment, the inverter circuit 65 is disposed on the front side (+ Z side) of the pump cover 32, and the circuit board 61 is in direct contact with the pump cover main body 32a having a high heat dissipation effect while ensuring insulation. Further, an oil flow path is formed in the pump unit 30 from the suction port 32e to the discharge port 32f, and oil having a constant temperature (for example, 120 ° C.) or less flows through the pump cover 32.
For this reason, the heat generated in the circuit board 61 is effectively cooled via the pump cover 32, and the temperature rise is suppressed. That is, the pump cover 32 that comes into contact with the oil flowing in the pump unit 30 directly cools the circuit board 61 of the inverter circuit 65 and also serves as a heat sink, so that cooling can be effectively realized.

(2) In the present embodiment, the heating element 62 of the inverter circuit 65 is in direct contact with the top plate portion 63 a of the inverter cover 63. For this reason, the heat generated by the heat generating element 62 can be dissipated from the inverter cover 63. Moreover, by using a copper inlay board for the circuit board 61, the heat generated in the inverter circuit 65 can be easily transmitted to the pump cover 32, and the cooling efficiency is improved.

(3) In this embodiment, the motor unit 20, the pump unit 30, and the motor drive unit 60 are provided side by side along the axial direction, and since they have a cylindrical compact shape, they are used for various transmissions as well. can do.

(4) In the present embodiment, part of the oil sucked from the suction port 32e enters the gap between the through hole 31a of the pump body 31 and the shaft 41, and lubricates the shaft support portion. That is, the through hole 31a functions as a sliding bearing member that rotatably supports the shaft 41 by oil that flows into the gap with the shaft 41. However, in order to prevent the intrusion of oil into the motor unit 20, a sliding bearing is used by using a sucked oil while arranging a seal material or the like at a predetermined position to prevent the oil from entering the motor unit 20. Can be realized.
Therefore, the shaft 41 has a double bearing structure constituted by the sliding bearing member of the pump unit 30 and the bearing 55 of the motor unit 20. For this reason, even if the inner rotor 37 receives pressure from the oil, the tilt of the shaft 41 can be suppressed by the double bearing structure, so that the inner rotor 37 is mounted on the wall surface of the pump case (that is, the pump body 31 and the pump cover 32). It is possible to suppress the sliding resistance from increasing.

(5) In the present embodiment, since the suction port 32e and the discharge port 32f are provided in the pump cover 32, cooling can be performed at a position close to the inverter circuit 65, and the cooling efficiency of the inverter circuit 65 is increased.

[Modification of First Embodiment]
(Modification with heat dissipation member)
In the electric oil pump 10 according to the first embodiment shown in FIG. 1, the circuit board 61 of the inverter circuit 65 is in direct contact with the pump cover main body 32a while ensuring insulation. However, the present invention is not limited to this structure. For example, as shown in FIG. 2, a heat radiating member 66 involved in heat conduction can be interposed between the circuit board 61 and the pump cover main body 32a. 1 modification).

As the heat radiating member 66, for example, a thermosetting resin having a high thermal conductivity such as silicone rubber, a heat radiating sheet, a heat radiating gel, or the like can be used. When using a thermosetting resin, for example, after applying the resin to the pump cover main body 32a, the circuit board 61 is assembled to the pump cover main body 32a so as to be in pressure contact with the resin, and the resin is cured, so that the inverter circuit can be easily 65 can be formed.

In this modified example, by using the heat radiation member 66, the circuit board 61 of the inverter circuit 65 can be reliably brought into contact with the pump cover main body 32a, so that the cooling efficiency of the circuit board 61 can be improved.

Further, for example, as shown in FIG. 3, the positions of the circuit board 61 and the heat generating element 62 are reversed in the axial direction, and the heat generating element 62 is arranged on the rear side (−Z side) from the circuit board 61. On the other hand, the circuit board 61 may be in direct contact with the top plate portion 63a of the inverter cover 63 while ensuring insulation (second modification).
In this modification, the heat generating element 62 of the inverter circuit 65 can be reliably brought into contact with the pump cover main body 32a via the heat radiating member 66, so that the cooling efficiency of the heat generating element 62 can be improved. Further, since the circuit board 61 is in direct contact with the top plate portion 63 a of the inverter cover 63 while ensuring insulation, heat generated in the circuit board 61 can be radiated from the inverter cover 63.

Further, for example, as shown in FIG. 4, in the motor drive unit 60, a heat radiation member 66 can be provided on the rear side (−Z side) of the top plate portion 63a of the inverter cover 63 to be brought into contact with the heat generating element 62 ( Third modification).
In this modification, the heat generating element 62 is reliably brought into contact with the top plate portion 63a by interposing a heat radiating member 66 involved in heat conduction between the heat generating element 62 of the inverter circuit 65 and the top plate portion 63a. Therefore, the heat of the heating element 62 is effectively radiated from the inverter cover 63 to the outside, and the temperature rise is suppressed.

(Modification with multiple circuit boards)
In the first embodiment shown in FIG. 1, an example of the inverter circuit 65 in which two heating elements 62 of the same type are mounted on one circuit board 61 is shown. However, the present invention is not limited to the inverter circuit 65 having this structure. For example, as shown in FIG. 5, an inverter circuit 65 in which the heating elements 62 are mounted on the two

circuit boards

61a and 61b can be used (the first circuit). 4 modification). Further, the number of circuit boards 61 is not limited to two but may be three or more. Further, a plurality of heat generating elements 62 mounted on one circuit board 61 may be used, or different types of heat generating elements (for example, any of capacitors, microcomputers, power ICs, field effect transistors (FETs), etc.). good.

According to this modification, the use of the plurality of circuit boards 61 for the inverter circuit 65 increases the degree of freedom in the position when the inverter circuit 65 is disposed on the motor driving unit 60. For example, in the circuit board 61 on which the heat generating element 62 having a large heat generation amount is mounted, only the heat generating element 62 can be arranged on the pump cover main body 32a side as shown in FIG. Further, in the circuit board 61 on which the heating element 62 having a large element size is mounted, the arrangement can be changed to a place where there is a sufficient space. Thus, by changing the arrangement of the circuit board 61 in the motor drive unit 60 according to the characteristics, heat dissipation and space arrangement can be effectively realized.

(Modified example in which the arrangement of the inverter circuit is changed)
In the electric oil pump 10 according to the first embodiment shown in FIG. 1, the inverter circuit 65 is arranged with respect to the central axis J in the motor drive unit 60. However, the present invention is not limited to this structure. For example, as shown in FIG. 6, the circuit board 61 a and the heating element 62 included in the inverter circuit 65 are arranged on the −X side (left side in the figure) in the radial direction from the central axis J. (5th modification).

As shown in FIG. 1, in the pump unit 30, the suction port 32 e is disposed on the −X side (left side in the drawing) in the radial direction from the central axis J, whereas the discharge port 32 f has a diameter from the central axis J. It is arranged on the X side (right side in the figure) of the direction. The low-temperature (for example, 120 ° C.) oil sucked from the suction port 32e is gradually heated by the heat from the inverter circuit 65 until reaching the discharge port 32f, and the temperature rises. For this reason, the cooling efficiency as a heat sink decreases as it approaches the discharge port 32f.

In this modification, the circuit board 61a and the heating element 62 of the inverter circuit 65 are arranged on the −X side (left side in the drawing) in the radial direction from the central axis J. For this reason, the inverter circuit 65 can be cooled by the oil of low temperature (for example, 120 degreeC) by the side of the inlet 32e before temperature rises by heat radiation, and cooling efficiency improves. Therefore, for example, by arranging the inverter circuit 65 including a field effect transistor (FET) that generates a large amount of heat at this position, cooling can be effectively realized.

(Modified example in which the arrangement of the heating elements is changed)
In the first embodiment shown in FIG. 1, an example of the inverter circuit 65 in which two heating elements 62 of the same type are mounted on one circuit board 61 is shown. However, the present invention is not limited to the inverter circuit 65 having this structure. For example, as shown in FIG. 7, a part of the heating elements 68 not mounted on the circuit board 61c is connected to the circuit board 61c by the wiring 69. An inverter circuit 65 having a structure can also be used (sixth modification).

In this modification, for example, when the heating element 68 is an element that generates a large amount of heat, the heating element 68 is arranged directly on the pump cover main body 32a on the −X side (left side in the drawing) in the radial direction from the central axis J. Further, since cooling can be performed with oil at a low temperature (for example, 120 ° C.) on the suction port 32e side, cooling can be effectively realized.
Note that either or both of the heat generating element 68 and the circuit board 61c may be disposed on the pump cover main body 32a with a heat dissipation member 66 involved in heat conduction interposed therebetween.

The above sixth modification shows an example in which some of the heating elements 68 that are not mounted on the circuit board 61c are directly arranged on the pump cover body 32a on the −X side (left side in the drawing) in the radial direction from the central axis J. It was. However, as shown in FIG. 8, for example, a recess 32g is provided in a part of the pump cover main body 32a on the −X side (left side in the drawing) in the radial direction from the central axis J, and a heat dissipation member 74 is interposed in the recess 32g. Alternatively, the heat generating element 68 may be disposed and connected to the circuit board 61c by the wiring 75 (seventh modified example).

By disposing the heating element 68 in the recess 32g, the surface area of the pump cover main body 32a facing the heating element 68 is increased, and the heat dissipation effect is further increased. Further, the height of the heating element 68 in the axial direction can be reduced by the amount of the recess 32g, and the motor drive unit 60 as a whole can be made compact. Although the heat generating element 68 can be directly accommodated in the concave portion 32g, it is preferable to dispose the heat generating element 68 in the concave portion 32g via the heat dissipating member 74.

As the heat dissipation member 74, for example, a thermosetting resin having a high thermal conductivity such as silicone rubber, a heat dissipation sheet, a heat dissipation gel, or the like can be used. When using a thermosetting resin, for example, after applying an appropriate amount of the heat radiation member 74 in the recess 32g, the heat generating element 68 is fixed to the pump cover body 32a, and the heat generation element 68 is placed in the recess 32g. 74. By curing the heat radiating member 74 in this state, the heat radiating member 74 can be easily filled in the recess 32g. In addition, by forming irregularities on the surface of the pump cover main body 32a, the surface area can be increased to further enhance the heat dissipation effect.

Examples of the heating element 68 accommodated in the recess 32g formed on the pump cover main body 32a side include a tall and low heat resistant component such as a capacitor, but may be other components. .

[Second Embodiment]
Next, an electric oil pump according to a second embodiment of the present invention will be described. In the first embodiment, the suction port 32e is provided on the −X side (left side in the drawing) of the pump cover 32 in the radial direction from the central axis J, and the discharge port 32f is on the X side (right side in the drawing) in the radial direction from the central axis J. ) Is shown. On the other hand, in the electric oil pump in the present embodiment, the discharge port is formed at a position different from the pump cover 32. Hereinafter, the difference from the first embodiment will be mainly described. In the electric oil pump according to the present embodiment, the same components as those of the electric oil pump according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 9 is a cross-sectional view showing an electric oil pump according to the second embodiment.
In the electric oil pump 100 according to the present embodiment, in the pump body 31 of the pump unit 30, the radial direction extends from the central axis J to the X side (right side in the figure), and extends from the bottom surface of the recess 33 to the rear side (−Z side). In addition, a delivery port 31d communicating with the motor unit 20 is provided. In addition, a discharge port 73 for discharging oil is provided on a part of the bottom surface 21 a of the housing 21 on the X side (right side in the drawing) in the radial direction from the central axis J. Further, an oil circulation filter 76 is provided on the rear side (−Z side) of the discharge port 73 as necessary. The discharge port 73 may be provided not on the bottom surface portion 21 a of the housing 21 but on a part of the stator holding portion 21 b on the X side (right side in the drawing) in the radial direction from the central axis J.

<Operation of this embodiment>
Since the operation when the electric oil pump device 100 according to the present embodiment is operated is the same as that of the first embodiment, the description thereof will be omitted and the flow of oil will be described.

The suction port 32e of the electric oil pump 10 is connected to an oil pan (not shown) in which oil is stored by a flow pipe (not shown), and the oil pan side tip of the flow pipe is immersed in the oil. Due to the negative pressure generated by the rotation of the inner rotor 37 of the electric oil pump 100, the oil stored in the oil pan enters the electric oil pump 100 through the suction port 32e and reaches the suction port 32c. The oil is sucked into the pump chamber 33 from the suction port 32 c, is then pumped to the delivery port 31 d, passes through the pump unit 30, and flows into the motor unit 20. In the motor unit 20, the oil flows from the front side (+ Z side) to the rear side (−Z side) between the inner peripheral surface of the stator 50 and the outer peripheral surface of the rotor 40 and is discharged to the discharge port 73. Thereby, the coil 53 of the stator 50 can be cooled more efficiently and the rotor 40 can be cooled. The discharged oil is supplied into a transmission (not shown). The supplied oil generates hydraulic pressure at the relevant location, and then it is refluxed and stored again in the oil pan.

<Effect of this embodiment>
(1) The pump cover 32 is usually made of a metal such as an aluminum alloy, has a large heat capacity and a large surface area, and therefore has a high heat dissipation effect. In the present embodiment, the inverter circuit 65 is disposed on the front side (+ Z side) of the pump cover 32, and the circuit board 61 is in direct contact with the pump cover main body 32a having a high heat dissipation effect while ensuring insulation. Further, an oil flow path is formed in the pump unit 30 from the suction port 32 e to the delivery port 31 d, and oil having a certain temperature (for example, 120 ° C.) or less flows through the pump cover 32.
For this reason, the heat generated in the circuit board 61 is effectively cooled via the pump cover 32, and the temperature rise is suppressed. That is, the pump cover 32 that comes into contact with the oil flowing in the pump unit 30 directly cools the circuit board 61 of the inverter circuit 65 and also serves as a heat sink, so that cooling can be effectively realized.

(2) In the present embodiment, the heating element 62 of the inverter circuit 65 is in direct contact with the top plate portion 63 a of the inverter cover 63. For this reason, the heat generated by the heat generating element 62 can be radiated from the inverter cover 63. Moreover, by using a copper inlay board for the circuit board 61, the heat generated in the inverter circuit 65 can be easily transmitted to the pump cover 32, and the cooling efficiency is improved.

(3) In the present embodiment, the motor unit 20, the pump unit 30, and the motor driving unit 60 are superposed in the axial direction, and have a cylindrical compact shape. Can be used.

(4) Generally, a coil generates the most heat in a motor. The heat generated by the coil is transmitted to the stator core. That is, since the motor unit 20 generates a large amount of heat from the stator 50, increasing the cooling efficiency of the stator 50 leads to an improvement in the cooling efficiency of the entire motor unit 20. In the present embodiment, oil supplied from the outside is sucked into the pump unit 30 from the suction port 32e by the pump rotor 35 and flows through the motor unit 20 via the delivery port 31d. And the stator 50 can be cooled at the same time. Since the oil absorbs heat generated by the motor due to the internal circulation of the motor unit 20, the motor does not become excessively high in temperature, and a reduction in the rotational efficiency of the motor can be suppressed. That is, the electric oil pump device 100 having a structure with a high cooling effect can be provided.

[Modification of Second Embodiment]
In the above embodiment, the rotor 40 and the stator 50 of the motor unit 20 can be simultaneously cooled by sending oil into the motor unit 20 via the delivery port 31d. However, it is also possible to adopt a configuration without the delivery port 31d. In this case, an axial gap between the shaft 41 and the pump body 31 is used. That is, the axial gap between the shaft 41 and the pump body 31 serves as an outlet for sending oil from the pump unit 30 to the motor unit 20.
In this case, the through hole 31a functions as a sliding bearing member that rotatably supports the shaft 41.

According to such a modification, it is not necessary to separately provide the delivery port 32d, and the processing becomes easy. Further, the oil flowing from the pump unit 30 can be used as the lubricating oil, and the oil can be efficiently sent into the motor unit 20.

Note that a cutout portion may be provided on at least one of the outer peripheral surface of the shaft 41 or the inner peripheral surface of the pump body 31. Thereby, when oil passes between the shaft 41 and the pump body 31, the flow path resistance is reduced, and the oil can be more efficiently sent from the pump unit 30 to the motor unit 20.

Further, in the pump body 31, in addition to the above-mentioned sliding bearing member, a bearing can also be used. In this case, the oil may pass through the inside of the bearing or may pass between the shaft 41 and the bearing.

[Third Embodiment]
Next, an electric oil pump according to a third embodiment of the present invention will be described. In the first embodiment, an example in which the suction port 32e and the discharge port 32f are provided in the pump cover 32 is shown. On the other hand, in the electric oil pump in the present embodiment, the suction port 32 e and the discharge port 32 f are provided in the pump body 31. Hereinafter, the difference from the first embodiment will be mainly described. In the electric oil pump according to the present embodiment, the same components as those of the electric oil pump according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 10 is a cross-sectional view showing an electric oil pump according to the third embodiment.
In the electric oil pump 110 according to the present embodiment, the suction port 32e extends from the pump chamber 33 in the protrusion 31c of the pump body 31 toward the -X side (left side in the drawing) and reaches the outer surface of the protrusion 31c. . On the other hand, the discharge port 32f extends from the pump chamber 33 to the X side (right side in the drawing) in the protruding portion 31c in the pump body 31, and reaches the outer surface of the protruding portion 31c.
The suction port 32e and the discharge port 32f are connected to the pump rotor 35 via the suction port 32c and the discharge port 32d, respectively. As a result, oil can be sucked into the pump rotor 35 and discharged from the pump rotor 35. Specifically, due to the negative pressure generated in the pump chamber by the rotation of the pump rotor 35, oil stored in an oil pan (not shown) is sucked into the pump chamber from the suction port 32e via the suction port 32c. The The sucked oil is discharged from the pressurizing region to the discharge port 32f via the discharge port 32d.

The electric oil pump 110 according to the present embodiment also has the same operations and effects as the electric oil pump 10 according to the first embodiment. In the present embodiment, since the pump body 31 is provided with the suction port 32e and the discharge port 32f, it is more effective when the heat transferred to the pump body 31 is cooled.

[Fourth Embodiment]
Next, an electric oil pump according to a fourth embodiment of the present invention will be described. In the present embodiment, the pump body 31 is provided with a bearing portion. Hereinafter, the difference from the first embodiment will be mainly described. In the electric oil pump according to the present embodiment, the same components as those of the electric oil pump according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 11 is a cross-sectional view showing an electric oil pump according to the fourth embodiment.
The electric oil pump 120 according to the present embodiment includes a ball bearing 31f as a bearing portion that supports the shaft 41 on the rear side (−Z side) of the pump body main body 31b.
The ball bearing 31f is fitted in a recess 31g provided in the pump body main body 31b, and is fixed by the pump body main body 31b from the circumferential direction of the ball bearing 31f. That is, in the present embodiment, the pump body main body 31b also serves as a bearing holder.

Therefore, it is not necessary to newly provide a region for installing the bearing holder in the pump body main body 31b, so that the effective volume of the pump body can be increased. For this reason, it is possible to increase the heat capacity and to easily dissipate the inverter circuit.

Further, in the present embodiment, the shaft 41 has a double bearing structure including the ball bearing 31 f and the bearing 55 of the motor unit 20. For this reason, even if the inner rotor 37 receives pressure from the oil, the tilt of the shaft 41 can be suppressed by the double bearing structure, so that the inner rotor 37 is mounted on the wall surface of the pump case (that is, the pump body 31 and the pump cover 32). It is possible to suppress the sliding resistance from increasing.

Further, in the present embodiment, as in the first embodiment, since the pump cover 32 is provided with the suction port 32e and the discharge port 32f, the pump body 31 is provided with the suction port 32e and the discharge port 32f. Compared with the third embodiment, since oil flows closer to the inverter circuit 65, the heat generated in the inverter circuit 65 can be effectively cooled.

In the present embodiment, an example in which the ball bearing 31f is provided as the bearing portion is shown, but other structures that function as the bearing portion may be used. For example, a sliding bearing member as described in the modification of the first embodiment and the second embodiment can be used instead of the ball bearing 31f or together with the ball bearing 31f.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and gist of the invention.

For example, in the first embodiment, in the pump unit 30, the suction port 32e is provided on the −X side (left side in the figure) in the radial direction from the central axis J, and the discharge port 32f is disposed on the X side in the radial direction from the central axis J (see FIG. However, the arrangement of the suction port 32e and the arrangement of the discharge port 32f can be reversed. In this case, the inverter circuit 65 according to the modified example of the first embodiment may be disposed in the opposite direction with respect to the central axis J in the case where the inverter circuit 65 is asymmetrical with respect to the central axis J (FIGS. 6 to 8). Also in the second embodiment and the fourth embodiment, it is also possible to apply the arrangement of the inverter circuit 65 according to the modification of the first embodiment. Furthermore, in 2nd Embodiment, the inlet 32e provided in the pump cover 32 can also be provided in the pump body 31 like 3rd Embodiment. Further, the length, shape, inner diameter, etc. of the suction port 32e and the discharge port 32f in the first embodiment and the fourth embodiment, the shape, width, height height, etc. of the suction port 32c and the discharge port 32d, etc. in the second embodiment. The length, shape, inner diameter and the like of the delivery port 31d can be appropriately changed as necessary.

This application claims priority based on Japanese Patent Application No. 2017-040629 filed on March 3, 2017, and uses all the contents described in the Japanese application.

DESCRIPTION OF SYMBOLS 10 Electric oil pump 12 Housing 20 Motor part 21 Housing 30 Pump part 31 Pump body 31d Outlet 32 Pump cover

32e Suction port

32f Discharge port 33 Pump chamber (concave part)
35 Pump Rotor 37 Inner Rotor 38 Outer Rotor 40 Rotor 41 Shaft 50 Stator 55 Bearing 60 Motor Drive 61 Circuit Board 62 Heating Element 63 Inverter Cover 65 Inverter Circuit 73 Discharge Port

Claims

A motor unit having a shaft supported rotatably about a central axis extending in the axial direction;
A pump unit located on one axial side of the motor unit, driven by the shaft extending from the motor unit, and discharging oil;
A motor drive unit that is located on one axial side of the motor unit via the pump unit and drives the motor unit;
The motor part is
A rotor rotatable around the shaft;
A stator disposed radially outside the rotor;
A housing for housing the rotor and the stator,
The pump part is
A pump rotor attached to the shaft;
A pump body that houses the pump rotor, and includes a recess including a side wall surface and a bottom surface located on the other axial side of the motor unit, and an opening on the one axial side of the motor unit;
A pump cover that closes the opening,
The motor drive unit is
An inverter circuit for controlling the driving of the motor unit;
An inverter cover that covers the inverter circuit;
The inverter circuit is an electric oil pump that is in thermal contact with the pump cover.
A suction port for sucking the oil is provided at an arbitrary position of the pump cover, and a discharge port for discharging the oil is provided on a side opposite to the position of the suction port with respect to the central axis of the pump cover. Item 4. The electric oil pump according to Item 1.
A suction port for sucking the oil is provided at an arbitrary position of the pump cover, and a delivery port communicating with the motor unit on a side opposite to the position of the suction port with respect to the central axis on the bottom surface of the recess. The electric oil pump according to claim 1, wherein a discharge port for discharging the oil is provided on a bottom surface or a side surface of the housing.
A suction port for sucking the oil is provided at an arbitrary position of the pump body, and a discharge port for discharging the oil is provided on a side opposite to the position of the suction port with respect to the central axis of the pump body. Item 4. The electric oil pump according to Item 1.
The electric oil pump according to any one of claims 1 to 4, wherein the pump cover is in thermal contact with the inverter circuit via a heat dissipation member.
The electric oil pump according to any one of claims 2 to 5, wherein the inverter circuit is arranged closer to the suction port than the central axis.
The electric oil pump according to any one of claims 1 to 6, wherein the inverter circuit includes a circuit board and a heating element, and the heating element is in thermal contact with the inverter cover.
The electric oil pump according to claim 7, wherein the heating element of the inverter circuit is in thermal contact with the inverter cover via the heat radiating member.
The electric oil pump according to claim 7 or 8, wherein the heating element of the inverter circuit is disposed closer to the suction port than the central axis.
The electric oil pump according to any one of claims 7 to 9, wherein the heating element in the inverter circuit includes a field effect transistor.
The electric oil pump according to any one of claims 7 to 10, wherein the circuit board of the inverter circuit is a copper inlay board.
The electric oil pump according to any one of claims 7 to 11, wherein the circuit board of the inverter circuit is a plurality of boards.
The electric oil pump according to any one of claims 1 to 12, wherein the pump body has a bearing portion.
The electric oil pump according to claim 13, wherein the bearing portion includes a ball bearing.
The electric oil pump according to claim 13 or 14, wherein the bearing portion includes a sliding bearing.