JP6550893B2 - Machine-electric integrated unit - Google Patents

Description

  The present invention relates to a machine-electric integrated unit.

  In a drive unit provided in an automobile, cooling fins are attached to a power control unit (PCU) for driving and controlling a motor of a rear wheel drive system of the automobile, and cooling is performed in a gear case containing a rear wheel gear mechanism and a differential gear. Place the PCU on top of the gear case so that the fins protrude. Then, by arranging the differential gear so that part of the differential gear is immersed in the lubricating oil, there is a driving device that cools the PCU by putting the lubricating oil scraped up by the differential gear rotating with the traveling of the vehicle on the cooling fins. It is disclosed (patent document 1).

JP, 2006-264442, A

  However, when the vehicle is stopped and the gear is not rotated, the lubricating oil is not scraped up by the gear, so that the amount of the lubricating oil corresponding to the PCU is small, and the cooling performance of the PCU is deteriorated.

  The problem to be solved by the present invention is to provide a mechanical-electrical integrated unit that suppresses a decrease in cooling performance when the vehicle is stopped.

  In the present invention, the power converter includes a plurality of coolers that cool the semiconductor element, and the drive unit includes at least one of a motor and a gear, a case that accommodates the component, and a first unit that accumulates in the case. 1 medium is provided, a part of one of the coolers is in contact with the first medium in the case, and the other cooler is in contact with the second medium having higher thermal conductivity than the first medium. Solve the above problems.

  According to the present invention, when the vehicle is stopped, since the cooler is in contact with the first medium accumulated in the case, even when heat is transmitted to the cooler due to heat generation of the semiconductor element, Since the cooler is cooled by the first medium, it has an effect of suppressing a decrease in cooling performance when the vehicle is stopped.

FIG. 2 is a cross-sectional view of a mechanical-electrical unit according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a mechanical-electrical unit according to another embodiment of the present invention. FIG. 7 is a cross-sectional view of a mechanical-electrical unit according to another embodiment of the present invention. FIG. 7 is a cross-sectional view of a mechanical-electrical unit according to another embodiment of the present invention. It is sectional drawing of the in-wheel motor which concerns on other embodiment of this invention. It is sectional drawing of the in-wheel motor which concerns on other embodiment of this invention. It is sectional drawing of the in-wheel motor which concerns on the modification of this invention. It is sectional drawing of the in-wheel motor which concerns on the modification of this invention. It is sectional drawing of the in-wheel motor which concerns on other embodiment of this invention. It is sectional drawing of the in-wheel motor which concerns on the modification of this invention.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

First Embodiment
FIG. 1 is a cross-sectional view of a mechanical-electrical unit according to an embodiment of the present invention. The electromechanical unit according to the present embodiment is provided in a vehicle, for example.

  The mechanical-electrical unit 100 includes a drive unit 10 and a power converter 20, and is a unit in which the drive unit 10 and the power converter 20 are integrated.

  The drive unit 10 includes a gear box 11, a gear 12, a bearing 13, and a medium 14. The drive unit 10 is a transmission mechanism that transmits power output from the motor or engine to the wheels. The gear box 11 is a case that houses the gear 12, the bearing 13, and the medium 14. The gear 12 is in mesh with another gear (not shown) and is one of the components constituting the reduction gear. The gear 12 has a function of transmitting power to the wheels. The gear 12 is supported by a bearing 13. The bearing 13 rotatably supports the gear 12. The rotation axis of the gear 12 is sandwiched between the plurality of bearings 13.

  The medium 14 is a liquid medium for lubricating the bearing 13. Medium 14 is an oil. The medium 14 is accumulated in a space formed under the gearbox 11. A portion of the gear 12 is immersed in the medium 14. Therefore, when the gear 12 rotates, the medium 14 jumps up due to the rotation of the gear 12, and the medium 14 jumped up hits the bearing 13 or the like. Therefore, the bearing 13 is lubricated with oil by the rotation of the gear 12. That is, when oil is used as the medium 14, the gear 12, the bearing 13 and the medium 14 also function as a lubrication mechanism. For the medium 14, a liquid such as water may be used instead of oil.

  The power converter 20 includes semiconductor elements 21 and 22, insulating substrates 23 and 24, coolers 25 and 26, and a case 27. The semiconductor elements 21 and 22 are circuit elements included in the power conversion circuit, and are switching elements such as IGBTs or MOSFETs or diodes. The power conversion circuit configured by the semiconductor elements 21 and 22 is, for example, an inverter that converts the power of the battery into an alternating current, and is a circuit in which a pair of switching elements are connected in a bridge shape in three phases. The power conversion circuit included in power converter 20 is not limited to an inverter, and may be, for example, a converter.

  The semiconductor elements 21 and 22 are modularized, and the side faces of the semiconductor elements 21 and 22 facing each other are joined to the insulating substrates 23 and 24 by solder. That is, the semiconductor elements 21 and 22 are sandwiched between one side surface of the insulating substrate 23 and one side surface of the insulating substrate 24. Note that the semiconductor elements 21 and 22 may be configured as a single integrated module.

  The insulating substrates 23 and 24 are substrates for insulating between the semiconductor elements 21 and 22 and the coolers 25 and 26. The main surfaces of the insulating substrates 23 and 24 are joined to the surfaces of the modularized semiconductor elements 21 and 22 via solder.

The cooler 25 is a component for cooling the semiconductor elements 21 and 22 and is formed of aluminum. The cooler 25 and the insulating substrate 23 are bonded with, for example, an adhesive.
Fins are formed in one direction of the cooler 25, and the side opposite to the one direction is a surface along the main surface of the insulating substrate 23. The fin portion of the cooler 25 is in contact with the medium 14. A part of the cooler 25 is located in the gear box 11, while the other part of the cooler 25 is located in the case 27.

  The cooler 26 is a component for cooling the semiconductor elements 21 and 22 and is formed of copper. The cooler 26 and the insulating substrate 24 are bonded, for example, with an adhesive. Fins are formed in one direction of the cooler 26, and the side opposite to the one direction is a surface along the main surface of the insulating substrate 24. The fin portion of the cooler 26 is in contact with a medium (for example, air) different from the medium 14. That is, the cooler 25 is an oil-cooled cooler, and the cooler 26 is an air-cooled cooler.

  The case 27 is a housing that accommodates the semiconductor elements 21 and 22, the insulating substrates 23 and 24, and the coolers 25 and 26. The case 27 is integrated with the gearbox 11.

The thermal conductivity of the medium 14 is higher than the thermal conductivity of air that is the refrigerant of the cooler 26. Further, the thermal expansion coefficient (α ₂ ) of the cooler 26 is lower than the thermal expansion coefficient (α ₁ ) of the cooler 25.

  Next, the cooling function of the mechanical and electrical unit 100 will be described. When the semiconductor elements 21 and 22 are driven and the semiconductor elements 21 and 22 become heat sources, the heat of the semiconductor elements 21 and 22 is transmitted to the coolers 25 and 26 through the insulating substrates 23 and 24. The cooler 25 is cooled by the medium 14 and the cooler 26 is cooled by air. That is, a first heat transfer path is formed between the semiconductor elements 21 and 22 and the cooler 25, and a second heat transfer path is formed between the semiconductor elements 21 and 22 and the cooler 26. Then, the heat transmitted through the respective heat transfer paths is cooled by the medium 14 and the air.

  For example, when the vehicle is running, the temperature of the medium 14 becomes high. Therefore, even if the heat of the semiconductor elements 21 and 22 is transmitted through the first heat transfer path, it is difficult for the cooler 25 to cool the heat. On the other hand, since the cooler 26 is air-cooled, it can exhibit a sufficient cooling function even when the vehicle is traveling. Therefore, the heat of the semiconductor elements 21 and 22 is transmitted along the second heat transfer path and cooled by the cooler 26. Thereby, the heat | fever of the semiconductor elements 21 and 22 can be thermally radiated during driving | running | working of a vehicle.

  Further, for example, when the vehicle is stopped or when the accelerator is held while climbing up, the heat of the semiconductor elements 21 and 22 is hardly cooled by the cooler 26 even though the heat is transferred through the second heat transfer path. On the other hand, the cooler 25 is in contact with the medium 14, and the temperature of the medium 14 is low while the vehicle is stopped. The heat of the semiconductor elements 21 and 22 is transmitted along the first heat transfer path and cooled by the cooler 25. Thereby, the heat of the semiconductor elements 21 and 22 can be radiated while the vehicle is stopped.

  As described above, in the present embodiment, the power converter 20 includes the plurality of coolers 25 and 26 for cooling the semiconductor elements 21 and 22, and the drive unit 10 includes the gear 12, the gear box 11, and the medium accumulated in the case. 14, a portion of the cooler 25 contacts the medium 14 in the gearbox 11, and the conductivity of the refrigerant 14 is higher than the medium (air) in contact with the cooler 26. Thereby, even when the gear 12 does not rotate, the heat generated in the semiconductor element is dissipated through the cooler 25, so that the cooling performance when the vehicle is stopped can be enhanced. Further, when the temperature of the medium 14 becomes high while the vehicle is traveling, the heat generated by the semiconductor element is transferred to the cooler 26, and the heat of the cooler 26 is released to the air. Therefore, the cooling performance while the vehicle is traveling can be enhanced. Further, when the vehicle speed is increased, the wind speed is increased, so that the heat radiation performance of the cooler 26 can be further enhanced. Further, in the present embodiment, since a plurality of heat transfer paths having different heat release performances are formed, the transient heat performance and the steady heat performance can be improved.

In the present embodiment, the thermal expansion coefficient (α ₂ ) of the cooler 26 located on the heat transfer path from the semiconductor elements 21 and 22 to the medium 14 is on the heat transfer path from the semiconductor elements 21 and 22 to air. It is lower than the coefficient of thermal expansion (α ₁ ) of the cooler 25 located. In the plurality of heat transfer paths, since the heat dissipation medium is different, a temperature difference occurs between the paths. And when the component located on a heat-transfer path | route expand | swells with a heat | fever, there exists a possibility that a difference may arise in thermal expansion by the temperature difference between paths. In this embodiment, by setting the thermal expansion coefficient (α ₂ ) of the cooler 26 lower than the thermal expansion coefficient (α ₁ ) of the cooler 25, the thermal expansion difference can be reduced. Can be suppressed.

  Further, in the present embodiment, the cooler 25 is formed of aluminum and the cooler 26 is formed of copper. As a result, since the electromechanical integrated unit has a structure capable of reducing the thermal expansion difference, distortion due to the thermal expansion can be suppressed.

  In the present embodiment, although the gear unit is used as the drive unit 10 integrated with the power converter 20, the motor unit and the power converter 20 are integrated to configure the mechanical-electric integrated unit 100. You may In the electromechanical integrated unit 100 in which the motor unit and the power converter 20 are integrated, the rotor of the motor is rotatably supported by the bearing 13, and the motor, the bearing 13 and the medium 14 are accommodated in the motor case ing. Then, the medium 14 is scraped up by the rotation of the rotor, and the bearing 13 is lubricated.

  In the present embodiment, the drive unit 10 and the motor unit described above may be integrated with the power converter 20 to configure the mechanical-electrical unit 100.

  In the present embodiment, the cooler 26 may be formed of aluminum having a thermal expansion coefficient lower than that of the aluminum forming the cooler 25.

  In the present embodiment, the insulating substrates 23 and 24 may be configured such that the thermal expansion coefficient of the insulating substrate 24 is lower than the thermal expansion coefficient of the insulating substrate 23. In the present embodiment, the difference between the medium 14 that contacts the cooler 25 (first medium) and the medium that contacts the cooler 26 (second medium) is defined by thermal conductivity. It may be a rate. That is, the heat capacity of the first medium may be higher than the heat capacity of the second medium, or the heat transfer coefficient of the first medium may be higher than the heat transfer coefficient of the second medium.

Second Embodiment
FIG. 2 is a cross-sectional view of an electromechanical and integrated unit according to another embodiment of the present invention. In this example, the point which provides the shock absorbing material 28 differs with respect to 1st Embodiment mentioned above. Other configurations are the same as those in the first embodiment described above, and the description thereof is incorporated.

  The power converter 20 includes a buffer material 28 in addition to the semiconductor elements 21 and 22. The cushioning material 28 is a member for cushioning the expansion of the cooler 26, and is formed in a plate shape. The buffer material 28 is sandwiched between the insulating substrate 24 and the cooler 26. The buffer material 28 is fixed to the insulating substrate 24 and the cooler 26 by an adhesive or solder.

  As described above, in the present embodiment, the power converter 20 is provided with the buffer member 28 that buffers the thermal expansion of the cooler 26. As a result, since the electromechanical integrated unit has a structure capable of reducing the thermal expansion difference, distortion due to the thermal expansion can be suppressed.

  In the present embodiment, the buffer material may be provided in the power converter 20 after making the thermal expansion coefficients of the cooler 25 and the cooler 26 the same.

  As a modification of this embodiment, as shown in Drawing 3, power converter 20 may be provided with shock absorbing materials 28 and 29. FIG. 3 is a cross-sectional view of a mechanical-electrical unit according to a modification. The cushioning material 29 is a member for cushioning the expansion of the cooler 25 and is formed in a plate shape. The buffer material 29 is sandwiched between the insulating substrate 23 and the cooler 25. Also, the buffer amount of the buffer 28 is larger than the buffer amount of the buffer 29. The buffer amount of the buffer materials 28 and 29 is defined by, for example, Young's modulus. As a result, since the electromechanical integrated unit has a structure capable of reducing the thermal expansion difference, distortion due to the thermal expansion can be suppressed.

Third Embodiment
FIG. 4 is a cross-sectional view of an electromechanical and integrated unit according to another embodiment of the present invention. In this example, the shape of the cooler 26 is different from that of the first embodiment described above. Other configurations are the same as those in the first embodiment described above, and the description thereof is incorporated.

  The cooler 26 is formed such that the cross section of the cooler 26 is curved toward the power conversion circuit. The cross section of the cooler 26 is a surface along the heat transfer direction of heat transferred from the semiconductor elements 21 and 22 to the cooler 26. In the example of FIG. 4, the direction of the x-axis is the heat transfer direction. The power conversion circuit is a circuit formed by the semiconductor elements 21 and 22. The cross section of the cooler 26 has a convex shape protruding toward the power conversion circuit.

  The thermal conductivity of the medium 14 is higher than the thermal conductivity of air serving as the refrigerant of the cooler 26. Therefore, for example, when the heat generated in the semiconductor elements 21 and 22 is transmitted to the cooler 25 while the vehicle is stopped, the heat of the cooler 25 is radiated by the medium 14. On the other hand, when the heat generated by the semiconductor elements 21 and 22 is transferred to the cooler 26, the heat of the cooler 26 is not easily dissipated. As described above, in the present embodiment, since the cross section of the cooler 26 is curved toward the power conversion circuit, when the cooler 26 expands due to heat, the cooler 26 is in a curved state. Transforms into a flat state. Thereby, distortion due to the thermal expansion difference can be suppressed.

  In the present embodiment, the cooler 26 has a curved shape in the cross section along the xz plane, but the cooler 26 may have a curved shape in the cross section along the xy plane.

Fourth Embodiment
FIG. 5 is a cross-sectional view of a mechanical-electrical unit according to another embodiment of the present invention. Each configuration of the electromechanical integrated unit is the same as that of the first embodiment described above, and the description thereof is incorporated as appropriate.

  In FIG. 5, x indicates the traveling direction of the vehicle, y is the lateral direction of the vehicle, and z is the vertical direction of the vehicle (height direction of the vehicle). The positive direction of the x-axis is the traveling direction when the vehicle travels forward.

  As shown in FIG. 5, the power converter (INV) 20 is disposed at a position behind the drive unit 10 with respect to the traveling direction (the positive direction of the x axis) when the vehicle moves forward. Thus, for example, when a falling object or the like falls on the vehicle, the power converter 20 can avoid a direct hit. Therefore, a highly secure unit can be realized.

Fifth Embodiment
FIG. 6 is a cross-sectional view of an in-wheel motor according to another embodiment of the present invention. The electromechanical integrated unit is integrated with the wheel. Each configuration of the electromechanical integrated unit is the same as that of the first embodiment described above, and the description thereof is incorporated as appropriate.

In FIG. 6, x indicates the traveling direction of the vehicle, y is the left-right direction of the vehicle, and z is the vertical direction of the vehicle (the height direction of the vehicle). The positive direction of the x-axis is the traveling direction when the vehicle travels forward. L ₁ represents the position of the axis of rotation of the gear 12 included in the reduction gear 10a, L ₂ represents the position of the rotation axis of the rotor of the motor 10b.

  The drive unit 10 includes a reduction gear 10 a and a motor 10 b. The drive unit 10 and the power converter 20 are provided in the wheel 30. The reduction gear 10a has the same configuration as the drive unit 10 shown in the first embodiment, and includes a gear box 11, a gear 12, and the like. The motor 10b is integrated with the reduction gear 10a. The rotation shaft of the motor 10 b is connected to the gear 12, whereby the driving force generated by the rotation of the rotor of the motor 10 b is transmitted to the gear 12. The output shaft of the speed reducer 10a corresponds to the tire rotation axis (tire axis). A motor case that is a housing of the motor 10 b is integrated with the gear box 11.

  The reduction gear 10 a is disposed such that the rotation axis of the gear 12 is offset with respect to the rotation axis of the rotor in the height direction of the vehicle. In other words, the position of the rotation axis of the gear 12 is lower than the rotation axis of the rotor in the height direction of the vehicle.

  The power converter (INV) 20 is disposed rearward of the reduction gear 10 a with respect to the traveling direction (the positive direction of the x axis) when the vehicle moves forward. Moreover, the power converter 20 is arrange | positioned in the height direction (z direction) of a vehicle in the position lower than the reduction gear 10a. Thus, for example, when a falling object or the like falls on the vehicle, the power converter 20 can avoid a direct hit. Therefore, a highly secure unit can be realized.

As a modification according to the present embodiment, as shown in FIG. 7, the power converter 20 may be disposed in a space formed by the speed reducer 10a and the motor 10b. FIG. 7 is a cross-sectional view of an in-wheel motor according to a modification. The display of the x-axis, y-axis, and z-axis is the same as in FIG. In FIG. 7, L ₁ represents the position of the axis of rotation of the gear 12 included in the reduction gear 10a, L ₂ represents the position of the rotation axis of the rotor of the motor 10b.

  The reduction gear 10 a is disposed such that the rotation axis of the gear 12 is offset with respect to the rotation axis of the rotor in the height direction of the vehicle. By offsetting the rotation shaft of the reduction gear 10a and the rotation shaft of the motor 10b, the portion positioned below the motor 10b in the height direction of the vehicle and at the left side of the reduction gear 10a in the lateral direction of the vehicle , Space is formed. And the power converter 20 is arrange | positioned in the said space. Furthermore, the power converter 20 is disposed at a position rearward of the speed reducer 10a with respect to the traveling direction (the positive direction of the x axis) when the vehicle moves forward.

  Thereby, for example, when a falling object or the like falls on the vehicle, the power converter 20 can avoid a direct hit, and a highly safe unit can be realized. In addition, the miniaturization of the mechanical and electrical unit can be realized.

As a modification according to the present embodiment, as shown in FIG. 8, the power converter 20 may be disposed below the speed reducer 10 a in the height direction of the vehicle. FIG. 8 is a cross-sectional view of an in-wheel motor according to a modification. The display of the x-axis, y-axis, and z-axis is the same as in FIG. In FIG. 8, L ₁ represents the position of the axis of rotation of the gear 12 included in the reduction gear 10a, L ₂ represents the position of the rotation axis of the rotor of the motor 10b.

  As shown in FIG. 8, the power converter 20 is provided on the bottom of the reduction gear 10 a. As a result, a highly safe machine-electric integrated unit can be realized.

Sixth Embodiment
FIG. 9 is a cross-sectional view of an in-wheel motor according to another embodiment of the present invention. In FIG. 9, L represents the position of the rotating shaft of the rotor of the motor 10b. The electromechanical integrated unit is integrated with the wheel. The drive unit 10 is a motor and includes a rotor, a stator, a bearing, a motor case, and a medium. Like the gear 12 according to the first embodiment, the rotor is supported in a rotatable state by a bearing. Then, due to the rotation of the rotor, the medium accumulated in the lower part of the motor case is scraped up, and the medium lubricates the bearing. The medium is oil or the like.

  The power converter 20 is disposed on the lower side of the reduction gear 10 a in the height direction of the vehicle, and specifically, is provided on the bottom surface of the drive unit 10. As a result, a highly safe machine-electric integrated unit can be realized.

  As a modification according to the present embodiment, as shown in FIG. 10, the power converter 20 may be disposed below the motor 10b in the height direction of the vehicle. FIG. 10 is a cross-sectional view of an in-wheel motor according to another embodiment of the invention. In FIG. 10, L represents the position of the rotation axis of the gear 12 included in the reduction gear 10a and the position of the rotation axis of the rotor of the motor 10b. The motor 10b is integrated with the reduction gear 10a, and the rotation axis of the motor 10b and the rotation axis of the reduction gear 10a are at the same height in the height direction of the vehicle. A medium 14a such as oil is accumulated in the lower part of the reduction gear 10a, and a medium 14b such as oil is accumulated in the lower part of the motor 10b.

DESCRIPTION OF SYMBOLS 10 ... Drive part 11 ... Gear box 12 ... Gear 13 ... Bearing 14 ... Medium 20 ... Power converter 21, 22 ... Semiconductor element 23, 24 ... Insulating board 25, 26 ... Cooler 27 ... Case 28, 29 ... Buffer material 30 ... wheel 100 ... machine-electric integrated unit

Claims (7)

A power conversion circuit having a plurality of semiconductor elements, and a power converter having a plurality of coolers for cooling the semiconductor elements;
And at least one of a motor and a gear, a case for containing the part, and a drive unit having a first medium accumulated in the case.
The first medium is a medium that lubricates a bearing that rotatably supports the component by rotation of the component.
The power converter and the drive unit are formed as an integral unit,
Among the plurality of coolers, a part of one cooler contacts the first medium while being located in the case, and the other cooler contacts the second medium,
An electromechanical integrated unit in which the thermal conductivity of the first medium is higher than the thermal conductivity of the second medium. In the machine-electric integrated unit according to claim 1,
The coefficient of thermal expansion of the component positioned on the heat transfer path from the plurality of semiconductor elements to the second medium is the coefficient of thermal expansion of the component positioned on the heat transfer path from the plurality of semiconductor elements to the first medium. Lower electro-mechanical integrated unit. In the machine-electric integrated unit according to claim 1 or 2,
The one cooler is made of aluminum,
The other cooler is an electromechanical integrated unit formed of at least one of aluminum and copper having a lower coefficient of thermal expansion than aluminum contained in the one cooler. In the electromechanical integrated unit according to any one of claims 1 to 3,
The electric power converter is an electromechanical integrated unit having a cushioning material that cushions expansion of the other cooler due to heat. In the electromechanical integrated unit according to any one of claims 1 to 3,
The power converter includes a first buffer material that buffers expansion due to heat of the one cooler, and a second buffer material that buffers expansion due to heat of the other cooler,
The shock absorbing amount of the second shock absorbing material is larger than the shock absorbing amount of the first shock absorbing material. A power conversion circuit having a plurality of semiconductor elements, and a power converter having a plurality of coolers for cooling the semiconductor elements;
And at least one of a motor and a gear, a case for containing the part, and a drive unit having a first medium accumulated in the case.
The power converter and the drive unit are formed as an integral unit,
Among the plurality of coolers, a part of one cooler contacts the first medium while being located in the case, and the other cooler contacts the second medium,
The thermal conductivity of the first medium is higher than the thermal conductivity of the second medium,
A mechanical-electrical integrated unit in which a cross section of the other cooling unit is formed in a curved shape toward the power conversion circuit. In the electromechanical integrated unit according to any one of claims 1 to 6,
The machine-electric integrated unit is provided in a vehicle,
The power converter is an electromechanical integrated unit that is disposed at a position behind the drive unit with respect to a traveling direction when the vehicle moves forward.

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