CN211082246U - Electric oil pump - Google Patents

Abstract

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

Description

Electric oil pump

technical field

The utility model relates to an electric oil pump.

Background technique

In recent years, a CVT (Continuously Variable Transmission), a DCT (Dual Clutch Transmission), and the like have been known as transmissions for automobiles and the like. Various shapes of these transmissions have been studied for the purpose of improving fuel efficiency.

In addition, in the transmission, a function capable of supplying oil using a motor during idling stop or the like is required, and in order to realize this function, an electric oil pump including an inverter circuit, a motor, and a pump is required.

For example, Patent Document 1 discloses an electric oil pump having a structure in which a part of a pump cover housing an inverter circuit becomes a part of a transmission.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2015-175291

Utility model content

The problem to be solved by the utility model

However, in the electric oil pump disclosed in Patent Document 1, since the pump cover also serves as a part of the transmission, the structure of the electric oil pump is limited by the structure of the transmission described above. Therefore, in various transmissions, the electric oil pump having the structure of an inverter circuit, a motor, and a pump cannot be commonly used.

In addition, in the electric oil pump, when higher output is required for reasons such as responsiveness, the heat generation of the elements used in the inverter circuit increases, so it is necessary to efficiently cool the inverter circuit.

The objective of this invention is to provide the electric oil pump which can cool an inverter circuit efficiently, and can be used for various transmissions in general.

means of solving problems

The electric oil pump of the utility model according to the first aspect of the present application includes a motor part supported so as to be rotatable about a central axis extending in the axial direction; and a pump part located in the axial direction of the motor part one side is driven by the shaft extending from the motor part to discharge oil; and a motor driving part is located on one side of the motor part in the axial direction with the pump part interposed therebetween, and drives the motor part, The motor unit includes a rotor rotatable around the shaft, a stator disposed radially outside the rotor, and a housing that accommodates the rotor and the stator, and the pump unit has : a pump rotor, which is mounted on the shaft; a pump body, which has a concave portion and an opening on one side of the motor portion in the axial direction, and the concave portion accommodates the pump rotor and includes a side wall surface and a a bottom surface on the other side in the axial direction of the motor part; and a pump cover that closes the opening, the motor drive part having: an inverter circuit that controls driving of the motor part; and an inverter a pump cover covering the inverter circuit, the inverter circuit being in thermal contact with the pump cover.

Utility model effect

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

Description of drawings

FIG. 1 is a cross-sectional view showing an electric oil pump according to a first embodiment.

FIG. 2 is a cross-sectional view showing a first modification of the motor drive unit.

3 is a cross-sectional view showing a second modification of the motor drive unit.

4 is a cross-sectional view showing a third modification of the motor drive unit.

FIG. 5 is a cross-sectional view showing a fourth modification of the motor drive unit.

6 is a cross-sectional view showing a fifth modification of the motor drive unit.

7 is a cross-sectional view showing a sixth modification of the motor drive unit.

8 is a cross-sectional view showing a seventh modification of the motor drive unit.

9 is a cross-sectional view showing an electric oil pump according to a second embodiment.

10 is a cross-sectional view showing an electric oil pump according to a third embodiment.

11 is a cross-sectional view showing an electric oil pump according to a fourth embodiment.

Detailed ways

Hereinafter, the electric oil pump according to the embodiment of the present invention will be described with reference to the drawings. In addition, in the following drawings, in order to facilitate understanding of each structure, the scale, number, etc. of the actual structure may be different from that of each structure.

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

In addition, in the following description, the positive side (+Z side) of Z-axis direction is called "front side", and the negative side (-Z side) of Z-axis direction is called "rear side". In addition, the rear side and the front side are only names for description, and do not limit the actual positional relationship and direction. In addition, unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) is simply referred to as the "axial direction", the radial direction with the central axis J as the center is simply referred to as the "radial direction", and the central axis J is referred to as the "radial direction". The circumferential direction of the center (ie, the direction around the center axis J) (theta direction) is simply referred to as the "circumferential direction".

In addition, in this specification, "thermal contact" includes not only the case where the target members are in direct contact with each other, but also the case where the members involved in heat conduction are interposed between the above-mentioned members. In addition, in this specification, "extending in the axial direction" includes not only the case of extending in the axial direction (Z-axis direction) strictly, but also the case of extending in a direction inclined within a range of less than 45° with respect to the axial direction . In addition, in this specification, "extending in the radial direction" includes extending in the radial direction (ie, the direction perpendicular to the axial direction (Z-axis direction)) strictly, and also includes extending in the radial direction by less than 45 In the case of extending in an inclined direction within the range of °.

[First Embodiment]

<Overall structure>

FIG. 1 is a cross-sectional view showing an electric oil pump according to the present embodiment.

The electric oil pump 10 of the present embodiment includes a motor unit 20 , a pump unit 30 , and a motor drive unit 60 . The motor unit 20, the pump unit 30, and the motor drive unit 60 are arranged in the axial direction.

The motor unit 20 has a shaft 41 supported so as to be rotatable around a central axis J extending in the axial direction, and the motor unit 20 rotates the shaft 41 to drive the pump. 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 the driving of the motor unit 20 .

Hereinafter, detailed description will be given for each component.

<Motor section 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, the rotor 40 is fixed to the outer peripheral surface of the shaft 41 , and the stator 50 is positioned radially outside the rotor 40 . Moreover, the bearing 55 is arrange|positioned at the axial direction rear side (-Z side) end part of the shaft 41, and supports the shaft 41 so that rotation is possible.

(Case 21)

As shown in FIG. 1 , the casing 21 has a bottomed thin cylindrical shape, and includes a bottom surface portion 21 a , a stator holding portion 21 b , a pump body holding portion 21 c , a side wall portion 21 d , and flange portions 24 and 25 . The bottom surface portion 21a constitutes a bottomed portion, and the stator holding portion 21b, the pump body holding portion 21c, and the side wall portion 21d constitute 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 side surface of the stator 50, ie, the outer side surface of the core back 51 mentioned later, is fitted to the inner side surface of the stator holding part 21b. Thereby, the stator 50 is accommodated in the case 21 . The flange portion 24 extends radially outward from the end portion on the front side (+Z side) of the side wall portion 21d. On the other hand, the flange portion 25 expands radially outward from the end portion on the rear side (-Z side) of the stator holding portion 21b. The flange portion 24 and the flange portion 25 are opposed to each other, and are fastened by fastening means not shown. Thereby, the motor part 20 and the pump part 30 are hermetically fixed in the casing 21 .

As the material of the case 21, for example, a zinc-aluminum-magnesium-based alloy or the like can be used, and specifically, a hot-dip galvanized-aluminum-magnesium alloy steel sheet and a steel strip can be used. Moreover, the bearing holding part 56 for holding the bearing 55 is provided in the bottom surface part 21a.

(rotor 40)

The rotor 40 has a rotor core 43 and a rotor magnet 44 . The rotor core 43 surrounds the shaft 41 in the circumferential direction (theta direction) and is fixed to the shaft 41. The rotor magnet 44 is fixed to the outer surface of the rotor core 43 in the circumferential direction (theta direction). The rotor core 43 and the rotor magnets 44 rotate together with the shaft 41 .

(stator 50)

The stator 50 surrounds the rotor 40 in the circumferential direction (theta direction), and rotates the rotor 40 around the central axis J. The stator 50 has a core back 51 , teeth 52 , coils 53 , and a bobbin (insulator) 54 .

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

(Bearing 55)

The bearing 55 is arranged 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, etc. of the bearing 55 are not particularly limited, and any known bearing can be used.

<Pump section 30>

The pump portion 30 is provided on one side in the axial direction of the motor portion 20, more specifically, on the front side (+Z axis side). The pump unit 30 has the same rotational axis as the motor unit 20, and is driven by the motor unit 20 via the shaft 41. The pump section 30 has a positive displacement pump that expands and contracts the volume of a closed space (oil chamber) to send oil under pressure. As a 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 . In addition, below, the pump body 31 and the pump cover 32 are also described as a pump casing.

(Pump body 31)

The pump body 31 is located on the front side (+Z axis side) of the motor portion 20 . The pump body 31 has: a 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 a protrusion 31c extending from the pump body main body 31b to the front side (+Z axis side). ) protrudes cylindrically. The inner diameter of the protruding portion 31c is larger than the inner diameter of the through hole 31a. The protruding portion 31c and the pump body main body 31b constitute a recessed portion 33 that is open to the pump cover 32 side. The through-hole 31a opens to the motor portion 20 side on the rear side (-Z side), and opens to the recessed portion 33 on the front side (+Z axis side). The through hole 31a is inserted into the shaft 41 and functions as a bearing member that rotatably supports the shaft 41 . The recessed portion 33 accommodates the pump rotor 35 and functions as a pump chamber (hereinafter also referred to as a pump chamber 33).

The pump body 31 is fixed in the pump body holding portion 21c on the front side (+Z axis side) of the motor portion 20 . In the radial direction, 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, in the radial direction, the outer peripheral surface of the pump body 31 and the inner peripheral surface of the casing 21 are sealed.

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

(Pump Rotor 35)

The pump rotor 35 is attached to the end portion on the front side (+Z axis side) of the shaft 41 and is accommodated in the pump chamber 33 . The pump rotor 35 has: an inner rotor 37 mounted on 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 end portion on the front side (+Z axis side) of the shaft 41 inside the inner rotor 37 . The inner rotor 37 rotates together with the shaft 41 in the circumferential direction (theta direction).

The outer rotor 38 surrounds the radially outer side of the inner rotor 37 and is an annular gear having teeth on the radially inner surface. The outer rotor 38 is rotatably accommodated in the pump chamber 33 . In the outer rotor 38, an inner housing chamber (not shown) in which the inner rotor 37 is accommodated is formed, for example, in a star shape. 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 are meshed with each other, and when the shaft 41 rotates the inner rotor 37 , the outer rotor 38 rotates along with the rotation of the inner rotor 37 . By rotating the inner rotor 37 and the outer rotor 38 , the volume of the space formed between the inner rotor 37 and the outer rotor 38 changes according to the rotational positions of the inner rotor 37 and the outer rotor 38 . The pump rotor 35 sucks oil from the suction port 32c described later by utilizing the volume change, pressurizes the sucked oil, and discharges the oil from the discharge port 32d. In the present embodiment, in the space formed between the inner rotor 37 and the outer rotor 38, a region where the volume increases (ie, sucks oil) is 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 has 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 generally made of metal such as aluminum alloy, and has a large heat capacity and a large surface area, so the heat dissipation effect is good. In addition, since the oil of a certain temperature (for example, 120° C.) or less flows inside the pump cover 32 , the temperature rise of the pump cover 32 can be suppressed.

The pump cover main body 32a has a radially extending disc shape. The pump cover main body 32a closes the opening on the front side (+Z axis side) of the recessed portion 33 . The flange portion 32b extends radially from the outer edge on the front side (+Z axis side) of the pump cover main body 32a. By having the flange portion 32b, the outer diameter of the pump cover 32 is made larger than the outer diameter of the protruding portion 31c of the pump body 31.

The suction port 32c is a crescent-shaped groove when viewed from the front side (+Z-axis side) of the pump rotor 35 . 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 an extent that is linked to the increase in the volume. Likewise, the discharge port 32d is also a crescent-shaped groove when viewed from the front side (+Z-axis side) of the pump rotor 35 . 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 such an extent that it is linked to the decrease in the volume.

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

<Motor drive unit 60>

The motor drive unit 60 is provided on the front side (+Z side) of the pump cover 32 and controls the drive of the motor unit 20 . The motor drive unit 60 has 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 the heating element 62 mounted on the circuit board 61 , supplies electric power for driving the coil 53 of the stator 50 of the motor unit 20 , and controls operations such as driving, rotating, and stopping the motor unit 20 . Further, by electrically connecting the motor drive unit 60 and the coil 53 using a wiring member such as a covered cable not shown, power supply and communication by electric signals between the motor drive unit 60 and the coil 53 of the stator 50 are performed.

The circuit board 61 outputs a motor drive signal. In the present embodiment, the circuit board 61 is directly arranged 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 . In addition, by using the copper embedded substrate as the circuit board 61, the heat generated by the heating element 62 is more easily transferred to the pump cover 32, thereby improving the cooling efficiency.

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. In addition, 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 an edge portion 63b.

The top plate portion 63a is in contact with the surface of the front side (+Z side) of the heating element 62 and extends in the radial direction. The edge portion 63b extends from the outer edge of the top plate portion 63a toward the rear side (-Z side). The rear side (-Z side) end surface of the edge portion 63b is in contact with the front side (+Z side) surface of the edge portion 32b of the pump cover 32 . The heat generating element 62 of the inverter circuit 65 is in direct contact with the top plate portion 63a of the inverter cover 63, so that the heat generated by the heat generating element 62 can be dissipated from the inverter cover 63.

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

<Action of the present embodiment>

(action of electric oil pump)

First, the 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 drive unit 60 from an external power source, and the external power source is connected via a connector part not shown. Thereby, a drive current is supplied from the motor drive part 60 to the coil 53 of the stator 50 via wiring members, such as a covered cable which is not shown in figure. A magnetic field is generated when a drive current is supplied to the coil 53 , and the rotor core 43 and the rotor magnet 44 in the rotor 40 are rotated together with the shaft 41 by the magnetic field. In this way, the electric oil pump 10 obtains the rotational driving force.

The drive current supplied to the coils 53 of the stator 50 is controlled by power ICs, circuit components, etc. in the motor drive section 60 , which are the heating elements 62 of the inverter circuit 65 . Specifically, the motor drive unit 60 detects the rotational position of the rotor 40 by detecting a change in the magnetic flux of a sensor magnet (not shown) using 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 the present embodiment is controlled.

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

(flow of oil)

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) storing oil through a flow pipe (not shown), and the oil pan side end of the flow pipe is immersed in the oil. The negative pressure generated by the rotation of the inner rotor 37 of the electric oil pump 10 causes the oil stored in the oil pan to enter the interior of the electric oil pump 10 through the suction port 32e and reach the suction port 32c. The oil sucked into the pump chamber 33 from the suction port 32c is sent to the discharge port 32d by pressure, and is discharged from the discharge port 32d to the discharge port 32f. The drained oil is supplied to the inside of the not-shown transmission. Oil pressure is generated at this point by the supplied oil, after which it is returned and stored in the oil pan again.

<Effects of the present embodiment>

(1) The pump cover 32 is usually made of metal such as aluminum alloy, and has a high heat dissipation effect due to its large heat capacity and large surface area. In the present embodiment, the inverter circuit 65 is arranged on the front side (+Z side) of the pump cover 32, so that the circuit board 61 is in direct contact with the pump cover body 32a with better heat dissipation effect while ensuring insulation. In addition, in the pump portion 30, a flow path of oil from the suction port 32e to the discharge port 32f is formed, and oil of a certain temperature (for example, 120°C) or lower flows in the pump cover 32.

Therefore, the heat generated by the circuit board 61 is effectively cooled via the pump cover 32, thereby suppressing the temperature increase. That is, the pump cover 32 in contact with the oil flowing in the pump unit 30 directly cools the circuit board 61 of the inverter circuit 65 and also functions as a radiator, so that cooling can be effectively achieved.

(2) In the present embodiment, the heating element 62 of the inverter circuit 65 is brought into direct contact with the top plate portion 63a of the inverter cover 63. Therefore, the heat generated by the heat generating element 62 can also be dissipated from the inverter cover 63 . In addition, by using copper embedded in the substrate as the circuit board 61, the heat generated in the inverter circuit 65 is more easily transferred 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 drive unit 60 are arranged in line in the axial direction, and since they have a compact cylindrical shape, they can be generally used for various transmissions.

(4) In the present embodiment, a 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 the oil flowing into the gap between the through hole 31a and the shaft 41 . However, in order to prevent oil from entering the motor portion 20 , a sealing material or the like is arranged at a predetermined portion to prevent the oil from entering the inside of the motor portion 20 , and the sliding bearing can be realized using the sucked oil.

Therefore, the shaft 41 has a double bearing structure including the above-described sliding bearing member of the pump portion 30 and the bearing 55 of the motor portion 20 . Therefore, even if the inner rotor 37 is pressurized by the oil, the inclination of the shaft 41 can be suppressed by the double bearing structure, so that the inner rotor 37 does not press the wall surface of the pump casing (ie, the pump body 31 and the pump cover 32 ), so that it is possible to An increase in sliding resistance is suppressed.

(5) In this 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 can be improved.

[Variation of the first embodiment]

(Variation in which a heat dissipation member is provided)

In the electric oil pump 10 of the first embodiment shown in FIG. 1 , the circuit board 61 of the inverter circuit 65 is brought into direct contact with the pump cover main body 32a after ensuring insulation. However, it is not limited to this structure. For example, as shown in FIG. 2, a heat dissipation member 66 involved in heat conduction may be interposed between the circuit board 61 and the pump cover main body 32a (a first modification).

As the heat dissipation member 66 , for example, a thermosetting resin with high thermal conductivity such as silicone rubber, a heat dissipation sheet, a heat dissipation gel, or the like can be used. In the case of 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 crimped to the resin, and by curing the resin, the reverse can be easily formed. Inverter circuit 65.

In this modification, since the circuit board 61 of the inverter circuit 65 can be brought into contact with the pump cover main body 32a more reliably by using the heat dissipation member 66, the cooling efficiency of the circuit board 61 can be improved.

In addition, for example, as shown in FIG. 3 , the positions of the circuit board 61 and the heating element 62 are reversed in the axial direction, and the heating element 62 is arranged at the rear side (-Z side) of the circuit board 61 so as to be different from the circuit board 61. While the heat dissipation member 66 is in contact, the circuit board 61 may be in direct contact with the top plate portion 63a of the inverter cover 63 after ensuring insulation (second modification).

In this modification, since the heat generating element 62 of the inverter circuit 65 can be brought into contact with the pump cover main body 32a via the heat dissipation member 66 more reliably, the cooling efficiency of the heat generating element 62 can be improved. In addition, since the circuit board 61 is in direct contact with the top plate portion 63 a of the inverter cover 63 while ensuring insulation, the heat generated by the circuit board 61 can also be dissipated from the inverter cover 63 .

Furthermore, for example, as shown in FIG. 4 , in the motor drive unit 60 , a heat dissipation member 67 may be provided on the rear side (-Z side) of the top plate portion 63a of the inverter cover 63 so as to be in contact with the heat generating element 62 (No. 3 variant).

In this modification, by interposing the heat dissipation member 67 involved in heat conduction between the heat generating element 62 of the inverter circuit 65 and the top plate portion 63a, the heat generating element 62 and the top plate portion 63a can be brought into more reliable contact. The heat of 62 is efficiently dissipated from the inverter cover 63 to the outside, thereby suppressing the temperature increase.

(Variation in which multiple boards are provided)

In the first embodiment shown in FIG. 1 , an example of an inverter circuit 65 in which two heating elements 62 of the same type are mounted on a single circuit board 61 is shown. However, the inverter circuit 65 is not limited to this structure. For example, as shown in FIG. 5 , an inverter circuit 65 in which the heating element 62 is mounted on the two circuit boards 61 a and 61 b may be used (fourth modification). example). In addition, the number of the circuit boards 61 may be not only two but also three or more. In addition, the number of heating elements 62 mounted on one circuit board 61 may be plural or different types of heating elements (for example, any of capacitors, microcomputers, power ICs, and field effect transistors (FETs)).

According to this modification, by using a plurality of circuit boards 61 for the inverter circuit 65, the degree of freedom of the position when the inverter circuit 65 is arranged in the motor drive unit 60 is increased. For example, in the circuit board 61 on which the heating element 62 having a large amount of heat is mounted, only the heating element 62 may be arranged on the side of the pump cover main body 32a as shown in FIG. 3 . In addition, in the circuit board 61 on which the heating element 62 having the large size of the element is mounted, the arrangement can be changed to a location where there is sufficient space. In this way, 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.

(Variation 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 symmetrically with respect to the central axis J in the motor drive unit 60 . However, it is not limited to this configuration. For example, as shown in FIG. 6 , the circuit board 61a and the heating element 62 included in the inverter circuit 65 may be arranged on the −X side in the radial direction with respect to the central axis J (left in the figure). side) position (5th modification).

As shown in FIG. 1 , in the pump portion 30, the suction port 32e is arranged on the -X side (left side in the figure) in the radial direction with respect to the central axis J, whereas the discharge port 32f is arranged on the side of the central axis J. The position on the X side in the radial direction (right side in the figure). 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 before reaching the discharge port 32f, and the temperature rises. Therefore, the closer to the discharge port 32f, the lower the cooling efficiency as a radiator.

In this modification, the circuit board 61a of the inverter circuit 65 and the heating element 62 are arranged on the -X side (left side in the figure) in the radial direction with respect to the central axis J. Therefore, the inverter circuit 65 can be cooled by the oil at a low temperature (eg, 120° C.) on the suction port 32e side before the temperature rises due to the heat radiation of the inverter circuit 65 , and the cooling efficiency can be improved. Accordingly, 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 achieved.

(Variation in which the arrangement of the heating element is changed)

In the first embodiment shown in FIG. 1 , an example of an inverter circuit 65 in which two heating elements 62 of the same type are mounted on a single circuit board 61 is shown. However, it is not limited to the inverter circuit 65 having this structure. For example, as shown in FIG. 7 , an inverter circuit 65 having a structure in which a part of the heating elements 68 not mounted on the circuit board 61c is passed through the wiring 69 may be used. Connected to the circuit board 61c (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 directly arranged on the -X side (left side in the figure) of the pump relative to the center axis J in the radial direction. Since the cover main body 32a can be cooled by the low temperature (for example, 120 degreeC) oil on the suction port 32e side, cooling can be achieved efficiently.

In addition, either or both of the heating element 68 and the circuit board 61c may be arranged on the pump cover main body 32a with the heat dissipation member 66 involved in heat conduction therebetween.

In the above-described sixth modification example, the pump cover main body 32a is shown in which a part of the heating element 68 not mounted on the circuit board 61c is directly arranged on the -X side (left side in the figure) in the radial direction with respect to the center axis J. example of. However, for example, as shown in FIG. 8 , a recessed portion 32g may be provided in a part of the pump cover main body 32a on the -X side (left side in the figure) in the radial direction with respect to the central axis J, and heat dissipation may be interposed in the recessed portion 32g. The heating element 68 is arranged on the component 74, and is connected to the circuit board 61c via the wiring 75 (seventh modification).

By arranging 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 improved. In addition, the height of the heating element 68 in the axial direction can be reduced by the amount of the concave portion 32g, and the overall size of the motor drive portion 60 can be reduced. The heating element 68 may be directly accommodated in the recessed portion 32g, but it is preferable to arrange the heating element 68 in the recessed portion 32g with the heat dissipation member 74 interposed therebetween.

As the heat dissipation member 74 , for example, a thermosetting resin with high thermal conductivity such as silicone rubber, a heat dissipation sheet, a heat dissipation gel, or the like can be used. In the case of using a thermosetting resin, for example, after applying an appropriate amount of the heat radiating member 74 in the recess 32g, the heating element 68 is fixed to the pump cover main body 32a, the heating element 68 is placed in the recess 32g, and the heat radiating member 74 crimp. By hardening the heat dissipation member 74 in this state, the heat dissipation member 74 can be easily filled in the concave portion 32g. In addition, the surface area of the cover main body 32a may be increased by forming irregularities or the like on the surface of the pump cover main body 32a, thereby further enhancing the heat dissipation effect.

As the heat generating element 68 housed in the recess 32g formed on the pump cover main body 32a side, for example, a large and low heat resistance member such as a capacitor can be mentioned, but other members may be used.

[Second Embodiment]

Next, the electric oil pump according to the second embodiment of the present invention will be described. In the first embodiment, it is shown that the suction port 32e is provided on the -X side (left side in the figure) of the pump cover 32 in the radial direction from the center axis J, and the discharge port 32f is provided on the radial direction from the center axis J. An example of the location of the X side (right side in the figure). On the other hand, in the electric oil pump of the present embodiment, the discharge port is formed at a position different from that of the pump cover 32 . Hereinafter, the difference from the first embodiment will be mainly described. In the electric oil pump of the present embodiment, the same components as those of the electric oil pump of the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

9 is a cross-sectional view showing an electric oil pump according to a second embodiment.

In the electric oil pump 100 of the present embodiment, in the pump body 31 of the pump portion 30, a transfer port 31d is provided at a position on the X side (right side in the figure) in the radial direction with respect to the central axis J, and the transfer port 31d extends from The bottom surface of the recessed portion 33 extends to the rear side (-Z side) and communicates with the motor portion 20 . In addition, a discharge port 73 for discharging oil to a part on the X side (right side in the figure) relative to the central axis J in the radial direction is provided in the bottom surface portion 21 a of the casing 21 . Moreover, the filter 76 for oil circulation is provided in the rear side (-Z side) of the discharge port 73 as needed. In addition, the discharge port 73 may not be provided in the bottom surface part 21a of the casing 21, but may be provided in a part of the stator holding part 21b on the X side (right side in the figure) of the center axis J in the radial direction.

(Function of this embodiment)

The operation of the electric oil pump 100 of the present embodiment during operation is the same as that of the first embodiment, so the description will be omitted, and the flow of oil will be described.

The suction port 32e of the electric oil pump 100 is connected to an oil pan (not shown) storing oil through a flow pipe (not shown), and the oil pan side end of the flow pipe is immersed in the oil. By the negative pressure generated by rotating the inner rotor 37 of the electric oil pump 100, the oil stored in the oil pan enters the inside of the electric oil pump 100 through the suction port 32e, and reaches the suction port 32c. After the oil is sucked into the pump chamber 33 from the suction port 32 c , the oil is pressure-fed to the delivery port 31 d , and then flows into the motor unit 20 through the pump unit 30 . In the motor portion 20 , 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 to the inside of the not-shown transmission. The supplied oil generates oil pressure at this location, after which it flows back and is stored in the oil pan again.

(Effect of the present embodiment)

(1) The pump cover 32 is usually made of metal such as aluminum alloy, and has a large heat capacity and a large surface area, so the heat dissipation effect is good. In this embodiment, the inverter circuit 65 is arranged on the front side (+Z side) of the pump cover 32, and the circuit board 61 is in direct contact with the pump cover body 32a having a good heat dissipation effect while ensuring insulation. Moreover, in the pump part 30, the flow path of the oil from the suction port 32e to the delivery port 31d is formed, and the oil below a certain temperature (for example, 120 degreeC) flows in the pump cover 32.

Therefore, the heat generated by the circuit board 61 is effectively cooled via the pump cover 32, thereby suppressing the temperature increase. That is, the pump cover 32 in contact with the oil flowing in the pump unit 30 directly cools the circuit board 61 of the inverter circuit 65 and also functions as a radiator, so that cooling can be effectively achieved.

(2) In the present embodiment, the heating element 62 of the inverter circuit 65 is brought into direct contact with the top plate portion 63a of the inverter cover 63. Therefore, the heat generated by the heat generating element 62 can also be dissipated from the inverter cover 63 . In addition, by using copper embedded in the substrate as the circuit board 61, the heat generated by the inverter circuit 65 is more easily transferred 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 drive unit 60 have a structure in which the motor unit 20, the pump unit 30, and the motor drive unit 60 are superimposed in the axial direction, respectively, and have a compact cylindrical shape, so it is commonly used in various transmissions.

(4) Generally, in the motor, the coil generates the most heat. The heat generated by the coils is transferred to the stator core. That is, in the motor unit 20 , since the stator 50 generates a large amount of heat, improving the cooling efficiency of the stator 50 contributes to improving the cooling efficiency of the motor unit 20 as a whole. In the present embodiment, oil supplied from the outside is sucked into the pump portion 30 from the suction port 32e by the pump rotor 35, and flows in the motor portion 20 through the delivery port 31d, so that the rotor 40 and the stator 50 of the motor portion 20 can be cooled simultaneously. The oil circulates inside the motor unit 20 to absorb heat generated by the motor, so that the temperature of the motor does not become too high, and it is possible to suppress a decrease in the rotational efficiency of the motor. That is, the electric oil pump 100 having a structure having a good cooling effect can be provided.

[Variation of the second embodiment]

In the above-described embodiment, the oil is fed into the motor unit 20 through the feed port 31 d, so that the rotor 40 and the stator 50 of the motor unit 20 can be cooled simultaneously. However, a configuration without the transfer port 31d may be employed. In this case, the 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 functions as a delivery port for delivering oil from the pump portion 30 to the motor portion 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 provide the conveyance port 31d separately, and processing becomes easy. In addition, the oil flowing in from the pump portion 30 can be used as lubricating oil, and the oil can be efficiently transported into the motor portion 20 .

In addition, a notch part may be provided in at least one of the outer peripheral surface of the shaft 41 or the inner peripheral surface of the pump body 31 . Thereby, when the oil passes between the shaft 41 and the pump body 31, the flow path resistance is reduced, and the oil can be sent from the pump part 30 to the motor part 20 more efficiently.

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

[The third embodiment]

Next, the electric oil pump according to the 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 of the present embodiment, the suction port 32e and the discharge port 32f are provided in the pump body 31 . Hereinafter, the difference from the first embodiment will be mainly described. In the electric oil pump of the present embodiment, the same components as those of the electric oil pump of the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

10 is a cross-sectional view showing an electric oil pump according to a third embodiment.

In the electric oil pump 110 of the present embodiment, the suction port 32e extends from the pump chamber 33 in the protruding portion 31c of the pump body 31 toward the -X side (left side in the figure), and reaches the outer surface of the protruding portion 31c. On the other hand, the discharge port 32f extends from the pump chamber 33 in the protruding portion 31c in the pump body 31 toward the X side (right side in the figure), 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. Thereby, the oil can be sucked into the pump rotor 35 and the oil can be discharged from the pump rotor 35 . Specifically, the negative pressure generated in the pump chamber by the rotation of the pump rotor 35 causes the oil stored in the oil pan (not shown) to be sucked into the pump chamber from the suction port 32e through the suction port 32c. The sucked oil is discharged from the pressurized area to the discharge port 32f via the discharge port 32d.

Also in the electric oil pump 110 of the present embodiment, the same functions and effects as those of the electric oil pump 10 of the first embodiment are achieved. In addition, in this embodiment, since the suction port 32e and the discharge port 32f are provided in the pump body 31, it is more effective when cooling the heat which moved to the pump body 31.

[Fourth Embodiment]

Next, the electric oil pump according to the 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 of the present embodiment, the same components as those of the electric oil pump of the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

11 is a cross-sectional view showing an electric oil pump according to a fourth embodiment.

The electric oil pump 120 of the present embodiment has a ball bearing 31f as a bearing portion that supports the shaft 41 on the rear side (-Z side) of the pump body 31b.

The ball bearing 31f is fitted into a recess 31g provided in the pump body 31b, and is fixed by the pump body 31b from the circumferential direction of the ball bearing 31f. That is, in the present embodiment, the pump body 31b also functions as a bearing holder.

Therefore, it is not necessary to separately provide a region for arranging the bearing holder in the pump body main body 31b, so that the effective volume of the pump body can be increased. Therefore, the heat capacity can be increased, and the heat dissipation of the inverter circuit can be facilitated.

In addition, in the present embodiment, the shaft 41 adopts a double bearing structure including the ball bearing 31 f and the bearing 55 of the motor unit 20 . Therefore, even if the inner rotor 37 is pressurized by the oil, the inclination of the shaft 41 can be suppressed by the two-bearing structure, so that the inner rotor 37 does not press against the wall surface of the pump housing (ie, the pump body 31 and the pump cover 32 ), so that sliding can be suppressed. resistance increases.

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

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

As mentioned above, although several embodiment of this invention was described, these embodiment is proposed only as an example, Comprising: It is not intended that the scope of the invention is limited. These embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the gist of the present invention. These embodiments and modifications thereof are included in the scope and spirit of the present invention, and are also included in the scope of the invention described in the scope of the claims and their equivalents.

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) with respect to the center axis J, and the discharge port 32f is provided on the side of the center axis J is located on the X side (right side in the figure) in the radial direction, but the arrangement of the suction port 32e and the arrangement of the discharge port 32f may be reversed. In this case, the arrangement of the inverter circuit 65 according to the modification of the first embodiment is asymmetrical with respect to the central axis J ( FIGS. 6 to 8 ), and can be arranged reversely with respect to the central axis J. In addition, in the second embodiment and the fourth embodiment, the arrangement of the inverter circuit 65 of the modification of the first embodiment can also be applied. Further, in the second embodiment, the suction port 32e provided in the pump cover 32 may be provided in the pump body 31 as in the third embodiment. In addition, the length, shape, inner diameter, etc. of the suction port 32e and the discharge port 32f in the first and fourth embodiments, and the shape, width, height, etc. of the suction port 32c and the discharge port 32d The length, shape, inner diameter, and the like of the delivery port 31d can be appropriately changed as needed.

The present application claims priority based on Japanese Patent Application No. 2017-040629 for which it applied on March 3, 2017, and the entire contents of the Japanese application are incorporated herein by reference.

Label description

10: Electric oil pump; 20: Motor part; 21: Housing; 30: Pump part; 31: Pump body; 31d: Delivery port; 32: Pump cover; 32e: Suction port; 32f: Discharge port; 33: Pump chamber ( 35: pump rotor; 37: inner rotor; 38: outer rotor; 40: rotor; 41: shaft; 50: stator; 55: bearing; 60: motor drive part; 61: circuit board; 62: heating element; 63: Inverter cover; 65: Inverter circuit; 73: Discharge port.

Claims (15)

1. An electric oil pump, characterized by comprising:

a motor unit having a shaft supported to be rotatable about a central axis extending in an axial direction;

a pump section that is located on one axial side of the motor section and that is driven by the shaft extending from the motor section to discharge oil; and

a motor drive section that is located on the one axial side of the motor section with the pump section interposed therebetween and drives the motor section,

the motor unit includes:

a rotor rotatable around the shaft;

a stator disposed radially outward of the rotor; and

a housing that houses the rotor and the stator,

the pump section includes:

a pump rotor mounted on the shaft;

a pump body having a recess that accommodates the pump rotor and includes a side wall surface and a bottom surface located on the other axial side of the motor unit, and having an opening portion on the one axial side of the motor unit; and

a pump cover for closing the opening,

the motor drive unit includes:

an inverter circuit that controls driving of the motor unit; and

an inverter cover covering the inverter circuit,

the inverter circuit is in thermal contact with the pump housing.

2. The electric oil pump according to claim 1,

a suction port through which the oil is sucked is provided at an arbitrary position of the pump cover, and a discharge port through which the oil is discharged is provided on a side of the pump cover opposite to the position of the suction port with respect to the central axis.

3. The electric oil pump according to claim 1,

a suction port through which the oil is sucked is provided at an arbitrary position of the pump cover, a delivery port communicating with the motor portion is provided on a side of the bottom surface of the recessed portion opposite to the position of the suction port with respect to the center axis, and a discharge port through which the oil is discharged is provided on a bottom surface or a side surface of the casing.

4. The electric oil pump according to claim 1,

a suction port through which the oil is sucked is provided at an arbitrary position of the pump body, and a discharge port through which the oil is discharged is provided on a side of the pump body opposite to the position of the suction port with respect to the center axis.

5. The electric oil pump according to any one of claims 1 to 4,

the pump cover is in thermal contact with the inverter circuit via a heat dissipation member.

6. The electric oil pump according to claim 2,

the inverter circuit is disposed closer to the suction port than the center axis.

7. The electric oil pump according to claim 2,

the inverter circuit includes a circuit board and a heat generating element in thermal contact with the inverter cover.

8. The electric oil pump according to claim 7,

the heat generating element of the inverter circuit is in thermal contact with the inverter cover via a heat dissipating member.

9. The electric oil pump according to claim 7,

the heating element of the inverter circuit is disposed closer to the inlet side than the center axis.

10. The electric oil pump according to any one of claims 7 to 9,

the heat generating element of the inverter circuit includes a field effect transistor.

11. The electric oil pump according to claim 7,

the circuit board of the inverter circuit is a copper-embedded substrate.

12. The electric oil pump according to claim 7,

the circuit board of the inverter circuit is a plurality of substrates.

13. The electric oil pump according to claim 1,

the pump body has a bearing portion.

14. The electric oil pump of claim 13,

the bearing portion has a ball bearing.

15. The electric oil pump according to claim 13 or 14,

the bearing portion has a sliding bearing.

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