JP7536725B2 - PCU case - Google Patents

Description

The present invention relates to a PCU case for use in an electric vehicle.

Conventionally, electric vehicles that run on the power of a motor, such as hybrid vehicles (HVs) and electric vehicles (EVs), are known.

Electric vehicles are equipped with a high-voltage battery that stores power to drive the motor, and an auxiliary battery that stores power to drive auxiliary equipment such as a water pump and a radiator fan. Electric vehicles are also equipped with a PCU (Power Control Unit) that controls the power. The PCU is equipped with a DC/DC converter that steps down the DC power output from the high-voltage battery to charge the auxiliary battery, and an inverter that converts the DC power output from the high-voltage battery into AC power to drive the motor.

The power of the motor is transmitted to a differential gear, and is distributed from the differential gear to the left and right drive wheels. Some electric vehicles use a configuration in which the motor and differential gear are housed in a single case, a so-called transaxle configuration. For example, Patent Document 1 proposes a structure in which the transaxle and PCU are integrated as a mounting structure for the PCU in an electric vehicle that uses a transaxle configuration.

In the proposed structure, a fixed base is provided to cover the opening at the top of the transaxle case that houses the motor, and a cooler is disposed above the fixed base. The cooler is supported on the fixed base by legs extending from its underside that are fixed to the fixed base with bolts. A support base is provided on the upper surface of the cooler, and an inverter board is supported on the support base. A DC/DC converter is disposed on the underside of the cooler. A terminal block is also provided on the fixed base, and bus bars connected to the inverter and the motor extend upward and downward from the terminal block, respectively. Each part disposed above the fixed base is covered with a cover that is removably attached to the transaxle case, and when the cover is removed, the connection between the inverter and the bus bars is exposed.

JP 2012-170177 A

This structure has the advantage that it is easy to connect the inverter to the busbar, but because the cooler, support base, and terminal block are provided on the fixed base, the structure is complex, and there are a large number of fastening parts for directly or indirectly fixing each of these parts to the fixed base, which raises concerns about high costs (parts costs, assembly costs).

The object of the present invention is to provide a PCU case that can integrate the power control unit with the motor while reducing costs.

To achieve the above object, the PCU case of the present invention is a PCU case used in an electric vehicle that runs on the power of a motor, which forms the outer shell of a power control unit that controls the power used in the electric vehicle, is provided integrally with a motor housing case that houses the motor, is formed integrally with a side wall that surrounds the periphery of the internal space, and has a partition that divides the internal space into the motor housing case side and the opposite side.

According to this configuration, the electric vehicle is equipped with a motor that generates power for driving and a power control unit that controls the electric power. The motor is housed in a motor housing case. The power control unit is integrated with the motor by having the PCU case, which forms the outer shell of the power control unit, integrally provided with the motor housing case. A partition wall that divides the internal space into the motor housing case side and the opposite side is formed in the PCU case integrally with the side wall that surrounds the several positions of the internal space. Therefore, some of the components of the power control unit can be arranged on the opposite side of the motor housing case side with respect to the partition wall, and the components can be supported by the partition wall. Therefore, the number of members that support the components can be reduced, and the number of fastening parts for directly or indirectly fixing the members to the PCU case or the motor housing case can be reduced. As a result, costs can be reduced.

This allows the power control unit to be integrated with the motor while still reducing costs.

In addition, the partition can block heat from inside the motor housing case, preventing heat damage to components located on the opposite side of the partition from the motor housing case.

A refrigerant passage through which the refrigerant passes may be formed on one side of the partition wall.

With this configuration, heat is exchanged between the components arranged on the side opposite the motor housing case side of the partition and the refrigerant passing through the refrigerant passage. Heat is also exchanged via the partition between the components arranged on the motor housing case side of the partition and the refrigerant passing through the refrigerant passage. Therefore, the components arranged on the motor housing case side of the partition and on the opposite side thereof can be cooled. As a result, these components can be protected from heat damage.

A pipe for passing the refrigerant flowing into or out of the refrigerant passage is connected to one side of the side wall, and a rib may be formed on that side.

According to this configuration, refrigerant can flow into the refrigerant passage from the pipe connected to one side of the side wall, or can flow out from the refrigerant passage to the pipe. However, if the pipe is connected to one side of the side wall, for example, wiring connected to the power control unit may become caught between the pipe and other components arranged around the PCU case, and the wiring may be damaged (deteriorated, broken, etc.). In addition, if the wiring becomes caught between the pipe and other components when routing the wiring, it becomes difficult to route the wiring, and the routing work is time-consuming. By forming a rib on one side of the side wall, the strength of the side wall can be increased while preventing the wiring from becoming caught between the pipe and other components.

There may be multiple ribs.

In this case, it is preferable that the multiple ribs are arranged at intervals greater than the thickness (width, diameter) of the wiring bundle of the wire harness connected to the power control unit, and the wiring bundle is passed between the multiple ribs. This makes it possible to prevent the wiring bundle of the wire harness from being pinched between the PCU case or piping and the components arranged around it in the event of a collision of the electric vehicle, and thus prevents the wiring bundle from being damaged.

Moreover, it is more preferable that the height of the rib is greater than the thickness of the wiring bundle. This effectively prevents the wiring bundle of the wire harness from being pinched between the PCU case or piping and the components arranged around it.

The PCU case has a blocking wall that is provided to block the internal space from the side opposite the motor housing case, and a female connector is provided on the blocking wall. The female connector may be arranged so that a socket into which a male connector attached to the end of the wire harness is inserted faces one side of the side wall (the piping side).

In this configuration, the wire bundle of the wire harness is likely to become pinched between the pipe and other components, but the provision of the rib prevents the wire bundle from becoming pinched between the pipe and other components.

The present invention allows the power control unit to be integrated with the motor while still reducing costs.

FIG. 2 is a side view showing a main configuration of the electric vehicle. FIG. 2 is an exploded perspective view of the transaxle and the PCU. FIG. 2 is a perspective view showing the PCU together with the upper end portion of the transaxle case. FIG. 2 is a top view of the PCU. FIG. 2 is a side view showing the inside of the PCU together with the upper end portion of the transaxle case. FIG. 2 is a perspective view showing the configuration inside the PCU case. FIG. 2 is an exploded perspective view showing the internal configuration of the PCU case.

The following describes in detail an embodiment of the present invention with reference to the attached drawings.

<Electric vehicles>
FIG. 1 is a side view showing a main configuration of an electric vehicle 1. As shown in FIG.

The electric vehicle 1 is, for example, a hybrid vehicle (HV) that employs a series hybrid system. The drive system 2 of the electric vehicle 1 includes a transaxle 11. The transaxle 11 houses, within a transaxle case 12 that forms the outer shell, a generator motor that generates electricity using engine power, a drive motor 13 that generates power for traveling, and a differential gear 14 that distributes the power of the drive motor 13 to the left and right drive wheels.

The electric vehicle 1 is also equipped with a PCU (Power Control Unit) 21 for controlling power. A PCU case 22 forming the outer shell of the PCU 21 is connected to the upper end 31 of the transaxle case 12. As a result, the PCU case 22 is provided integrally with the transaxle case 12, and the PCU 21 is integrated with the transaxle 11.

<Transaxle case>
FIG. 2 is an exploded perspective view of the transaxle 11 and the PCU 21.

The upper end 31 of the transaxle case 12 is generally rectangular in shape in plan view and is open upward. Three bus bars 32 connected to the U-phase winding, V-phase winding, and W-phase winding of the generator motor, respectively, and three bus bars 33 connected to the U-phase winding, V-phase winding, and W-phase winding of the drive motor 13, respectively, are provided within the upper end 31. The bus bars 32 are arranged at equal intervals in the front-rear direction along the left side wall 34 of the upper end 31 at the rear part of the upper end 31. The bus bars 33 are arranged at equal intervals in the front-rear direction along the left side wall 34 of the upper end 31 at the front part of the upper end 31. The upper ends of the bus bars 32, 33 protrude upward from the upper end of the transaxle case 12 (upper end 31).

<PCU>
Fig. 3 is a perspective view showing the PCU 21 together with the upper end portion 31 of the transaxle case 12. Fig. 4 is a view of the PCU 21 as seen from above. Fig. 5 is a side view showing the inside of the PCU 21 together with the upper end portion 31 of the transaxle case 12 with the inside of the PCU 21 seen through.

The lower part 41 of the PCU case 22 has side walls 42, 43, 44, 45 that are similar to but enlarged from the outer shape of the upper end 31 of the transaxle case 12, and is open downward. The PCU case 22 is placed over the upper end 31 of the transaxle case 12 from above, so that the side walls 42, 43, 44, 45 of the lower part 41 surround the periphery of the upper end 31. The side walls 42, 43, 44, 45 are integrally formed with a plurality of fixing parts 46 that extend from their lower edges to the periphery, and each fixing part 46 is fixed to the upper end 31 of the transaxle case 12 with fasteners such as bolts and nuts, so that the PCU case 22 is connected to cover the transaxle case 12 from above.

The left side wall 51 of the upper part 47 of the PCU case 22 is formed integrally with the left side wall 42 of the lower part 41, and the outer surfaces (left side) of these left sides 42, 51 are flush. In addition, the right side wall 52 of the upper part 47 is formed integrally with the right side wall 43 of the lower part 41, and the outer surfaces (right side) of these right sides 43, 52 are flush.

The front wall of the upper part 47 includes a first front wall 53 set back from the front wall 44 of the lower part 41 to the rear, and a second front wall 54 set back from the front wall 44 to the rear more than the first front wall 53. The first front wall 53 is located to the right of the second front wall 54, and the left edge of the first front wall 53 and the right edge of the second front wall 54 are connected by a connecting wall 55 extending in the front-rear direction. In addition, in the area surrounded by the upper edges of the left side wall 42, right side wall 43, and front wall 44 of the lower part 41 and the lower edges of the first front wall 53, second front wall 54, and connecting wall 55 of the upper part 47, a front ceiling wall 56 is provided across those edges.

The rear wall 57 of the upper part 47 is set back forward from the rear wall 45 of the lower part 41. In the area surrounded by the upper edges of the left side wall 42, right side wall 43 and rear wall 45 of the lower part 41 and the corner of the rear wall 57 of the upper part 47, a rear ceiling wall 58 is provided straddling these edges.

Figure 6 is an oblique view showing the configuration inside the PCU case 22. Figure 7 is an oblique view showing the configuration inside the PCU case 22 in an exploded view.

A partition wall 61 is provided inside the PCU case 22. The partition wall 61 extends in the front-rear and left-right directions, and is connected to the left side wall 51, right side wall 52, second front wall 54, and rear wall 57 of the upper part 47 of the PCU case 22, and is formed integrally with the left side wall 51, right side wall 52, second front wall 54, and rear wall 57. The partition wall 61 divides the internal space of the PCU case 22 into a space on the transaxle case 12 side and a space on the opposite side.

A refrigerant passage 62 through which the refrigerant flows is formed on the upper surface of the partition wall 61. A piping connection portion 63 is formed protruding from the upper surface of the front ceiling wall 56 of the PCU case 22. The piping connection portion 63 extends from the left end of the first front side wall 53 to the front surface of the front side wall 44 of the lower portion 41. A refrigerant supply path 64 (see FIG. 2) is formed penetrating the piping connection portion 63 in the front-rear direction, and the refrigerant supply path 64 communicates with the refrigerant passage 62 through an opening formed penetrating the first front side wall 53 and a communication path formed in the PCU case 22. The refrigerant passage 62 is formed in a labyrinth shape (approximately serpentine shape) that extends rearward from one end to which the communication path is connected, bends to the left, bends to the front and extends, bends further to the left, and then bends to the rear and extends.

A piping connection portion 65 is formed protruding from the upper surface of the rear ceiling wall 58 of the PCU case 22 at the same position in the left-right direction as the other end of the refrigerant passage 62. The piping connection portion 65 extends from the rear side wall 57 of the upper portion 47 to the rear surface of the rear side wall 45 of the lower portion 41. A refrigerant discharge passage 66 is formed penetrating the partition wall 61 and the piping connection portion 65 in the front-rear direction. The refrigerant discharge passage 66 is in communication with the refrigerant passage 62 via an opening formed in the rear side wall 57.

A cooling water pipe 71 is connected to the front pipe connection part 63. The cooling water pipe 71 is supplied with cooling water, for example, after passing through a radiator, by the action of a water pump, and the cooling water as a refrigerant is supplied from the cooling water pipe 71 to the refrigerant passage 62 through the refrigerant supply passage 64. On the other hand, one end of the cooling water pipe 72 is connected to the rear pipe connection part 65. The cooling water flowing through the refrigerant passage 62 is discharged to the cooling water pipe 72 through the refrigerant discharge passage 66. The other end of the cooling water pipe 72 is connected to the rear surface of the upper end part 31 of the transaxle case 12. An oil cooler is provided in the transaxle case 12, and the cooling water flowing from the cooling water pipe 72 into the transaxle case 12 is discharged through the oil cooler to the cooling water pipe 73 connected to the front surface of the upper end part 31 of the transaxle case 12. The cooling water discharged to the cooling water pipe 73 flows through the radiator and through the cooling water pipe 71. In the oil cooler, heat is exchanged between the cooling water passing through the oil cooler and the oil in the transaxle case 12.

The PCU 21 includes a DC/DC converter 81 and a control unit 82 that includes an inverter and a microcontroller.

The DC/DC converter 81 is disposed in the space above the partition wall 61 within the PCU case 22 and is supported by the partition wall 61. The electric vehicle 1 is equipped with a high-voltage battery that stores power for driving the drive motor 13, and an auxiliary battery that stores power for driving auxiliary equipment such as a water pump. The primary side of the DC/DC converter 81 is connected to the high-voltage battery, and the secondary side is connected to the auxiliary battery. When the remaining charge of the auxiliary battery decreases, the DC power output from the high-voltage battery is stepped down by the DC/DC converter 81, and the stepped-down DC power is supplied from the DC/DC converter 81 to the auxiliary battery, thereby charging the auxiliary battery.

The control unit 82 is disposed in the space below the partition wall 61 within the PCU case 22, and is supported by a support portion 83 (see FIG. 5) provided within the transaxle case 12. An inverter for driving the generator motor and an inverter for driving the drive motor 13 are mounted on the control unit 82. Each inverter is a three-phase voltage type inverter, and has a configuration in which a series circuit of two IGBTs (Insulated Gate Bipolar Transistors) is provided corresponding to each of the U-phase, V-phase, and W-phase, and these series circuits are connected in parallel with each other between the positive wiring and the negative wiring.

As shown in Figs. 2 and 5, six bus bars 84, 85 are arranged at intervals in the front-rear direction on the left side of the control unit 82. The three front bus bars 84 are connected to an inverter for driving the drive motor 13, and the three rear bus bars 85 are connected to an inverter for driving the generator motor. In each inverter, the bus bars 84, 85 are connected to the connection points of two IGBTs corresponding to the U, V, and W phases. The bus bars 84 corresponding to the U, V, and W phases are connected to the bus bars 33 corresponding to the U, V, and W phases provided in the upper end 31 of the transaxle case 12, respectively, so that the inverter is electrically connected to the drive motor 13. The bus bars 85 corresponding to the U, V, and W phases are connected to the bus bars 32 corresponding to the U, V, and W phases provided in the upper end 31 of the transaxle case 12, respectively, so that the inverter is electrically connected to the generator motor.

The PCU 21 also has a cover 91. The upper part 47 of the PCU case 22 is open upward, and the cover 91 is attached to the PCU case 22 so as to close the open upper part 47 from above.

A raised portion 92 is formed on the cover 91. The raised portion 92 has a front inclined surface 93 that extends at an angle so that it is higher toward the rear, and a rear inclined surface 94 that extends from the upper end of the front inclined surface 93 at an angle so that it is lower toward the rear. Two connector sockets 95 are provided on the rear inclined surface 94 with a space between them in the left-right direction. Each connector socket 95 is formed as an opening that penetrates the cover 91.

A high-voltage connector 96 is disposed within the raised portion 92. The high-voltage connector 96 is supported on the bulkhead 61 of the PCU case 22 via a bracket B made of sheet metal. The high-voltage connector 96 is exposed to the outside through two connector sockets 95. A PN (positive-negative) connector 97 (see FIG. 1) is connected to the high-voltage connector 96 within the connector socket 95. The PN connector 97 is attached to the tip of a wire harness 98 connected to the positive and negative terminals of the high-voltage battery. The high-voltage connector 96 is also electrically connected to the positive and negative wiring of each inverter within the PCU case 22. As a result, the positive and negative wiring of each inverter are electrically connected to the positive and negative terminals of the high-voltage battery, respectively, via the high-voltage connector 96, the PN connector 97, and the wire harness 98. For example, when the drive motor 13 is driven (powered operation), the DC power output from the high-voltage battery is converted to AC power by the inverter, and the AC power is supplied from the inverter to the motor.

A DC output terminal 99 is attached to the first front side wall 53 of the upper portion 47 of the PCU case 22. The secondary side of the DC/DC converter 81 is connected to the DC output terminal 99. The DC output terminal 99 is connected to the positive and negative terminals of the auxiliary battery by a wire harness, thereby electrically connecting the primary side of the DC/DC converter 81 to the auxiliary battery.

Furthermore, two thin plate-like ribs 101 are integrally formed on the rear wall 45 of the lower part 41 of the PCU case 22 to the right of the piping connection part 65. The two ribs 101 extend in the up-down and front-rear directions with a gap between them that is greater than the thickness (width, diameter) of the wiring bundle of the wire harness 98 to which the PN connector 97 is attached. The height of each rib 101 (the amount of protrusion from the rear wall 45) is greater than the thickness of the wiring bundle of the wire harness 98. The wiring bundle of the wire harness 98 is passed between the two ribs 101.

<Action and effect>
As described above, the electric vehicle 1 is equipped with the drive motor 13 that generates power for traveling and the PCU 21 that controls the electric power. The drive motor 13 is accommodated in the transaxle case 12. The PCU 21 is integrated with the drive motor 13 by the PCU case 22 that forms the outer shell of the PCU 21 being provided integrally with the transaxle case 12. In the PCU case 22, a partition wall 61 that divides the internal space into the transaxle case 12 side and the opposite side is formed integrally with a side wall that surrounds the several positions of the internal space. Therefore, the DC/DC converter 81 can be disposed on the opposite side of the transaxle case 12 side with respect to the partition wall 61, and the DC/DC converter 81 can be supported by the partition wall 61. Therefore, the number of members that support the components of the PCU 21 can be reduced, and the number of fastening parts for directly or indirectly fixing the members to the PCU case 22 or the transaxle case 12 can be reduced. As a result, costs can be reduced.

This allows the PCU 21 to be integrated with the drive motor 13 while still reducing costs.

The partition 61 also blocks heat from within the transaxle case 12, preventing heat damage to the DC/DC converter 81, which is located on the opposite side of the partition 61 from the transaxle case 12.

A refrigerant passage 62 through which a refrigerant passes is formed on the upper surface of the partition wall 61. Cooling water flows as a refrigerant through the refrigerant passage 62, and heat is exchanged between the DC/DC converter 81 and the cooling water passing through the refrigerant passage 62. Heat is also exchanged via the partition wall 61 between the control unit 82, which is disposed on the transaxle case 12 side of the partition wall 61, and the cooling water passing through the refrigerant passage 62. Therefore, the DC/DC converter 81 and the control unit 82 can be cooled. As a result, the DC/DC converter 81 and the control unit 82 can be well protected from heat damage.

The PCU case 22 is provided with a cover 91 that is provided to close the internal space from the side opposite the transaxle case 12 side, and a high-voltage connector 96 is provided inside the cover 91. A connector socket 95 that opens toward the rear side is formed in the cover 91, and a PN connector 97 attached to the tip of a wire harness 98 is connected to the high-voltage connector 96 via the connector socket 95.

A piping connection section 65 is formed on the rear side of the left end of the rear wall 57 of the upper part 47 of the PCU case 22, to which the cooling water piping 72 through which the refrigerant flowing out from the refrigerant passage 62 is connected, and two ribs 101 are formed on the rear wall 45 of the lower part 41 of the PCU case 22 on the right side of the piping connection section 65. If the cooling water piping 72 is connected to the piping connection section 65, the wiring bundle of the wire harness 98 may be pinched between the cooling water piping 72 and other members arranged around the PCU case 22, and the wiring of the wire harness 98 may be damaged (deteriorated, broken, etc.). In addition, if the wiring bundle of the wire harness 98 is pinched between the cooling water piping 72 and other members when routing the wire harness 98, it becomes difficult to route the wire harness 98, and the routing work is time-consuming. The rib 101 formed on the rear side wall 45 increases the strength of the rear side wall 45 while preventing the wiring bundle of the wire harness 98 from being pinched between the cooling water pipe 72 and other components.

Two ribs 101 are formed, and the two ribs 101 are arranged with a distance greater than the thickness (width, diameter) of the wiring bundle of the wire harness 98, and the wiring bundle of the wire harness 98 passes between the two ribs 101. Moreover, the height of each rib 101 is greater than the thickness of the wiring bundle of the wire harness 98. This prevents the wiring bundle of the wire harness 98 from being pinched between the PCU case 21 or the cooling water pipe 72 and a member arranged therearound (e.g., a dash panel) during a collision of the electric vehicle 1, and prevents the wiring bundle of the wire harness 98 from being damaged. The number of ribs 101 is not limited to two, and may be one, or three or more.

The upper ends of the bus bars 32, 33 connected to the generator motor and drive motor 13 protrude above the upper end of the transaxle case 12 (upper end 31), and the bus bars 32, 33 can be connected to the bus bars 84, 85 of the control unit 82 at a position above the upper end. This eliminates the need to provide openings in the transaxle case 12 or the PCU case 22 for connecting the bus bars 32, 33 to the bus bars 84, 85, lids to close the openings, and sealing members to seal between the openings and the lids, simplifying the configuration of the transaxle 11.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

For example, in the above embodiment, cooling water is supplied from the cooling water pipe 71 to the refrigerant passage 62, and the cooling water that passes through the refrigerant passage 62 is discharged to the cooling water pipe 72. However, cooling water may be supplied from the cooling water pipe 72 to the refrigerant passage 62, and the cooling water that passes through the refrigerant passage 62 may be discharged to the cooling water pipe 71.

The electric vehicle 1 is described as a hybrid vehicle that employs a series hybrid system, but there are no particular limitations as long as the vehicle uses the drive motor 13 as a driving source for traveling, and it may be a hybrid vehicle that employs a hybrid system of a type other than a series type, or it may be an electric vehicle (EV) that does not have an engine.

In addition, various design modifications may be made to the above-mentioned configuration within the scope of the claims.

1: Electric vehicle 12: Transaxle case (motor housing case)
13: Drive motor (motor)
22: PCU case 45: Rear wall (side wall)
51: Left side wall (side wall)
52: Right side wall (side wall)
53: First front side wall (side wall)
54: Second front side wall (side wall)
57: Rear wall (side wall)
61: Partition wall 62: Refrigerant passage 72: Cooling water piping (piping)
101: Ribs

Claims (2)

A PCU case used in an electric vehicle that runs on the power of a motor,
An outer shell of a power control unit that controls the power used in the electric vehicle,
The motor housing case is provided integrally with the motor housing case,
a partition wall that is formed integrally with a side wall that surrounds the periphery of the internal space, that is provided between a space on the motor housing case side in the internal space and a space on the opposite side, and that supports some of the components of the power control unit in the space on the opposite side;
a refrigerant passage for passing a refrigerant is formed on the opposite surface of the partition wall;
When the portion of the components is supported by the partition wall, the refrigerant passage contacts the portion of the components,
a piping provided on one side surface of the side wall so as to straddle the one side surface and the motor housing case, the piping having one end connected thereto through which a refrigerant flows into or flows out of the refrigerant passage;
A PCU case having a plurality of ribs formed on the one side surface, the ribs extending toward the motor housing case with intervals therebetween allowing wiring connected to the power control unit to pass therebetween. The PCU case according to claim 1, wherein the refrigerant passage is open to the opposite side and is formed so as to be closed from the opposite side by the part of the components when the part of the components is supported by the bulkhead.