Electric power device

An electric power device includes a power control unit that is fixed to an upper portion of an automatic transmission case, with a gap interposed between the power control unit and the automatic transmission case, and a battery that is connected to the power control unit by a first wire extending rearward in a vehicle front-rear direction from the power control unit.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2021-102410 filed on Jun. 21, 2021, incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The disclosure relates to an electric power device including a power control unit capable of converting electric power from a battery.

2. Description of Related Art

WO 2018/033346 discloses a transmission for an automobile including a hydraulic transmission control device, a transmission housing, an oil pan attached to the transmission housing, and a power electronics device. The power electronics device is supported on the transmission housing and the oil pan, and the hydraulic transmission control device and the power electronics device are juxtaposed below or on the side of the transmission housing.

SUMMARY

In the technology disclosed in WO 2018/033346, the power electronics device is provided at a position at which the power electronics device is readily affected by heat from the transmission, and is difficult to replace.

The disclosure provides technology that suppresses effects of heat on a power control unit, and facilitates replacement of the power control unit.

An electric power device according to an aspect of the disclosure includes a power control unit that is fixed to an upper portion of an automatic transmission case, with a gap interposed between the power control unit and the automatic transmission case, and a battery that is connected to the power control unit by a first wire extending rearward in a vehicle front-rear direction from the power control unit.

According to the above aspect of the disclosure, technology that suppresses effects of heat on the power control unit and facilitates replacement of the power control unit can be provided.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG.1is a perspective view of an electric power device1according to an embodiment. The electric power device1includes a power control unit10, an automatic transmission case12, a motor generator14, a first wire20, a second wire22, and a battery that is omitted from illustration. The electric power device1is provided in a hybrid electric vehicle can travel in a motor driving mode and an engine driving mode. Note that a vehicle in which the electric power device1is provided is not limited to a hybrid electric vehicle, and the electric power device1may be provided in a battery electric vehicle that travels in a motor driving mode alone.

The automatic transmission case12, the motor generator14, and an engine16are arranged in a vehicle front-rear direction, with the engine16being located at a forefront side of the vehicle. Gears and so forth of the automatic transmission are installed inside the automatic transmission case12. The automatic transmission case12is supported by a vehicle body frame18. The automatic transmission is a stepped transmission that automatically shifts transmission stages according to vehicle speed, an accelerator operation amount (or a throttle valve opening degree), and so forth. The automatic transmission is connected to a rotation shaft of the motor generator14or the engine16via an input shaft, and is connected to right and left wheels via an output shaft.

The motor generator14functions as an electric motor that is rotationally driven by receiving electric power supplied from the battery (omitted from illustration). The motor generator14also functions as a generator when being rotated by an external force, and can charge the battery. A rotor, which is the rotation shaft of the motor generator14, is connected to the input shaft of the automatic transmission. When driven, the motor generator14is controlled by the power control unit10, based on control commands from a motor control unit. The motor generator14is disposed between the automatic transmission case12and the engine16in the vehicle front-rear direction, and is disposed forward of the automatic transmission case12in the vehicle front-rear direction.

The engine16is a gasoline engine or a diesel engine, and a valve opening degree of a throttle valve, and so forth, are controlled based on control commands from an engine control unit. The motor generator14and the engine16function as power units of the vehicle to generate driving force, and output the generated driving torque to the automatic transmission case12via the rotation shaft.

The power control unit10converts direct current electric power from the battery into alternating current electric power based on drive signals from an electric power control unit, and outputs the alternating current electric power to the motor generator14. The power control unit10also converts alternating current electric power generated by regenerative electric power generation at the motor generator into direct current electric power, and outputs the direct current electric power to the battery, based on drive signals from the electric power control unit. The power control unit10includes an inverter and a converter, and can perform conversion between direct current on the battery side and three-phase alternating current on the motor generator14side.

The power control unit10has a case30, brackets24, and internal electrical equipment housed in the case30. The internal electrical equipment includes the inverter, the converter, and electrical circuits. The power control unit10is fixed to an upper portion of the automatic transmission case12, with a gap interposed between the power control unit10and the automatic transmission case12. The case30keeps circuit boards and so forth from being exposed. The case30is provided with terminal openings into which the first wire20and the second wire22can be respectively inserted.

The brackets24are formed as a pair, so as to project from the bottom of the case30in the vehicle front-rear direction, and are formed so as to have flange shapes. The brackets24are used to fix the power control unit10to the automatic transmission case12.

The power control unit10is connected to the battery by the first wire20and is connected to the motor generator14by the second wire22. The first wire20extends rearward in the vehicle front-rear direction from the power control unit10, and the second wire22extends forward in the vehicle front-rear direction from the power control unit10. The first wire20and the second wire22are cables that are detachably inserted into the power control unit10. This simplifies the layout of wiring to the motor generator14and the battery, facilitates connection to the power control unit10, and suppresses contact with other devices, as compared to when the first wire and the second wire pass (i.e., extend) along the side of the automatic transmission case12.

The motor generator14has a terminal block14aprovided at an upper portion of the motor generator14, and the terminal block14ais connected to the second wire22extending forward in the vehicle front-rear direction from the power control unit10. Accordingly, the layout of the second wire22is simplified, and the motor generator14can be connected to the power control unit10disposed on the upper portion of the automatic transmission case12such that the distance between the motor generator14and the power control unit10is a short distance.

FIG.2is a side view of the electric power device1according to the embodiment. The automatic transmission case12has a pair of fastening seats28formed to be raised upward (i.e., a pair of fastening seats28formed to protrude upward). Each fastening seat28has a seat face on which one bracket24is seated, and an internal thread for fastening. The fastening seats28are formed by die-casting so as to be raised upward, and performing cutting to form the internal threads therein. The fastening seats28are disposed facing each other in the vehicle front-rear direction. The fastening seats28rise upward from the upper face of the automatic transmission case12by several centimeters, for example.

The brackets24of the power control unit10are seated on the fastening seats28and fastened by screws. Thus, the power control unit10alone can be easily attached and detached, and can be easily removed when the power control unit10fails. Further, by forming the fastening seats28raised upward, the gap is formed between the case30of the power control unit10and automatic transmission case12, and the boards and the like inside the case30can be kept from being readily heated by the automatic transmission case12. Further, disposing the power control unit10on the upper portion of the automatic transmission case12suppresses interference with other devices, such as a hydraulic transmission control device disposed on the side of the automatic transmission case12.

The automatic transmission case12is tapered rearward in the vehicle front-rear direction, and the upper portion of the automatic transmission case12is disposed to be inclined downward, in a direction toward a vehicle-rearward side. The power control unit10is inclined in accordance with the incline of the upper portion of the automatic transmission case12and is inclined downward, in the direction toward the vehicle-rearward side. Accordingly, interference with other parts can be suppressed even though the power control unit10is disposed on the upper portion of the automatic transmission case12.

A battery26is a rechargeable direct current electric power source, and for example is a secondary battery. The battery26supplies electric power to the power control unit10, and is charged by receiving regenerative electric power output from the power control unit10. The battery26is connected to the power control unit10by the first wire20extending rearward in the vehicle front-rear direction from the power control unit10. Thus, the first wire20can be restrained from coming into contact with other devices as compared to when the first wire20passes (i.e., extends) along the side or the like of the automatic transmission case12.

FIG.3is a diagram illustrating removal of the power control unit10. The power control unit10is disposed below a vehicle body panel32, and is covered by the vehicle body panel32. The vehicle body panel32is provided with an opening32alarger than the power control unit10, andFIG.3illustrates a state in which the opening32ais open. The opening32ais normally closed by a lid (omitted from illustration), but the lid is removed and the opening32ais opened when the power control unit10is to be removed.

After removing the lid, a worker extracts the terminals of the first wire20and the second wire22from the power control unit10, unfastens the brackets24using a tool, detaches the power control unit10from the automatic transmission case12, and extracts the power control unit10through the opening32a. When replacing the power control unit10, the worker can easily attach a new power control unit10by inserting the power control unit10through the opening32a, fastening the brackets24, and connecting the first wire20and the second wire22to the power control unit10. As described above, the power control unit10does not have a structure in which the automatic transmission case12, the motor generator14, and the entire engine16need to be displaced in order to remove the power control unit10, and the power control unit10alone can be easily replaced.

FIG.4is a rear view of an electric power device100according to a first modification.FIG.4illustrates the electric power device100as viewed from a vehicle-rearward side. A pair of power control units110is provided on an upper portion of an automatic transmission case112. Brackets124are seated and fastened to fastening seats128formed to be raised upward on the upper portion of the automatic transmission case112, whereby the power control units110are fixed to the automatic transmission case112with a gap interposed therebetween.

The power control units110are located upward from a center C of the automatic transmission case112. This facilitates removal of the power control units110as compared with disposing the power control units on side faces of the automatic transmission case112. AlthoughFIG.4illustrates a form in which the power control units110are provided as a pair, this form is not limiting, and an arrangement may be made in which just one power control unit110is provided. In either case, the power control unit(s)110is/are fixed to the fastening seat(s)128at the upper portion of the automatic transmission case112.

FIG.5is a side view of an electric power device200according to a second modification. In the electric power device200according to the second modification, the positions of an automatic transmission case212and a motor generator214are different from those of the electric power device1illustrated inFIG.2. This difference occurs depending on the vehicle model. The automatic transmission case212is situated rearward of the engine16in the vehicle front-rear direction, and is situated forward of the motor generator214in the vehicle front-rear direction, with the engine16, the automatic transmission case212, and the motor generator214being disposed in succession in that order.

A power control unit210is seated and fastened to fastening seats228formed to be raised upward on an upper portion of the automatic transmission case212, whereby the power control unit210is fixed to the automatic transmission case212with a gap interposed therebetween.

The motor generator214has a terminal block214aon an upper portion thereof. The motor generator214is located rearward of the power control unit210, and accordingly a second wire222extends from the power control unit210rearward in the vehicle front-rear direction and is connected to the terminal block214a.

FIG.6is a side view of an electric power device300according to a third modification. The electric power device300according to the third modification has a different protection method for a power control unit310and a different connection method for the power control unit310and a motor generator314, as compared with the electric power device200illustrated inFIG.5. The power control unit310and the motor generator314are connected using bus bars.

The power control unit310is seated and fastened to fastening seats328formed to be raised upward on an upper portion of an automatic transmission case312, whereby the power control unit310is fixed to the automatic transmission case312with a gap interposed therebetween.

The power control unit310does not have a case, and a board is directly fixed to the fastening seats328of the automatic transmission case312. An accommodating portion38is provided on the upper portion of the automatic transmission case312, and the fastening seats328are provided in the accommodating portion38. The accommodating portion38has side wall portions40erected from the upper face of the automatic transmission case312, and a lid portion42capable of opening and closing an upper opening defined by the side wall portions40. The side wall portions40form a rectangular space. The lid portion42is engaged with the side wall portions40in a state in which the upper opening defined by the side wall portions40is closed. The lid portion42may be engaged with the side wall portions40by screws, or may be engaged by an engaging claw.

The power control unit310and the motor generator314are electrically connected by a first bus bar44, an intermediate terminal block46, and a second bus bar48. Costs can be reduced by connecting the power control unit310and the motor generator314by bus bars as compared to connecting the power control unit310and the motor generator314by cables.

The intermediate terminal block46is fixed to the upper side of the automatic transmission case312. At least an upper end portion of the intermediate terminal block46is provided within the accommodating portion38, and the entire intermediate terminal block46may be provided in the accommodating portion38. The first bus bar44is electrically connected to the power control unit310, projects rearward in the vehicle front-rear direction from the power control unit310, and is connected to the upper end portion of the intermediate terminal block46by bolts, screws, or the like.

Although the motor generator314is not provided with a terminal block at an upper portion thereof, the second bus bar48projecting forward in the vehicle front-rear direction is assembled to the motor generator314and is electrically connected to the motor generator314. The second bus bar48is linked to a lower end portion of the intermediate terminal block46by bolts, screws, or the like. The worker closes the lid portion42after linking the first bus bar44and the intermediate terminal block46. Thus, the electrical contacts of the power control unit310can be protected.

Note that a cover may be provided to cover the intermediate terminal block46and the second bus bar48. Also, the intermediate terminal block46and the second bus bar48may be integrally formed.

FIG.7is a side view of an electric power device400according to a fourth modification. The electric power device400according to the fourth modification has a different connection method for a power control unit410and a motor generator414, as compared with the electric power device200illustrated inFIG.5. The power control unit410and a motor generator414are connected using bus bars.

A case430of the power control unit410is fastened to fastening seats428formed to be raised upward on an upper portion of an automatic transmission case412, whereby the power control unit410is fixed to the automatic transmission case412with a gap interposed therebetween.

The case430is provided with a tool hole and a lid portion442that closes the tool hole. The tool hole is formed to extend through the upper face of the case430, and is formed at a position such that the tool can reach a first bus bar444. The first bus bar444is disposed within the case430, and is electrically connected to the power control unit410.

An intermediate terminal block446is fixed to the automatic transmission case412, and an upper end portion of the intermediate terminal block446is inserted into the case430. A second bus bar448is electrically connected to the motor generator414, projects forward in the vehicle front-rear direction from the motor generator414, and is connected to a lower end portion of the intermediate terminal block446. The lower end portion of the intermediate terminal block446and the second bus bar448may be covered by a cover.

It should be noted that the embodiment is only exemplary, and it will be understood by those skilled in the art that various modifications can be made to combinations of the components, and that such modifications are also within the scope of the disclosure.