Drive unit

Abstract

To provide a drive unit capable of shortening a length of a wire sending a detection signal in a resolver to a power control device.SOLUTION: In a drive unit 80, a transaxle 82 which is a drive device including motors MG (e.g., a first motor MG1 and a second motor MG2) and gears (e.g., a drive gear 26, a driven gear 28, a final gear 32, a differential gear 34, a reduction gear 36 and a power dividing mechanism 40) and a PCU 54 (a power control device 54) controlling power, which is received by the motors MG, are accommodated in the same case 18. A wire harness 96 which is a wire sending a detection signal in a resolver 90 (e.g., a first resolver 92 and a second resolver 94) which is rotary sensors of the motors MG from the resolver 90 to the power control device 54 is disposed only in the case 18.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a drive unit in which a drive device including a motor and a gear and a power control device for controlling the power transmitted and received by the motor are housed in the same case.

Background Art

[0002] A drive unit in which a drive device including a motor and a gear and a power control device for controlling the power transmitted and received by the motor are housed in the same case is known. For example, the one described in Patent Document 1 is such a drive unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to prevent the motor that functions as a power source from losing synchronization, the rotational state of the motor is detected by a resolver which is a rotation sensor, and the motor rotation control according to the detected rotational state of the motor is executed by the power control device. The resolver is fixed inside the case in the case. Generally, the wiring for sending the detection signal from the resolver to the power control device is drawn out of the case from near the position where the resolver is fixed to the case, arranged outside the case, and then drawn into the case housing the power control device. However, when the wiring is arranged outside the case in this way, the length of the wiring becomes long, which may lead to, for example, deterioration in the mountability of the drive unit on a vehicle (= ease of mounting) and an increase in the cost of the drive unit.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a drive unit capable of shortening the length of a wiring for sending a detection signal from a resolver to a power control device.

Means for Solving the Problems

[0006] The gist of the present invention is a drive unit in which a drive device including a motor and a gear and a power control device for controlling the power received and transmitted by the motor are housed in the same case, and a wiring for sending a detection signal from a resolver, which is a rotation sensor of the motor, to the power control device is arranged only inside the case.

Effects of the Invention

[0007] According to the drive unit of the present invention, a wiring for sending a detection signal from a resolver, which is a rotation sensor of the motor, to the power control device is arranged only inside the case. When compared with the case where the wiring for sending the detection signal from the resolver is arranged outside the case, the length of the wiring can be shortened when arranged only inside the case. Thereby, for example, the mountability of the drive unit on a vehicle can be improved and an increase in the cost of the drive unit can be suppressed.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments, the drawings are appropriately simplified or deformed, and the dimensional ratios, shapes, etc. of each part are not necessarily drawn accurately.

Examples

[0010] FIG. 1 is a diagram for explaining the configuration of a transaxle 82 of a drive unit 80 according to an embodiment of the present invention. The drive unit 80 is a drive unit for driving a vehicle 10. In FIG. 1, the transaxle 82 is shown in a skeleton diagram, and this skeleton diagram is illustrated so as to represent the schematic relative arrangement positions of the respective constituent members in the transaxle 82.

[0011] The vehicle 10 is a hybrid vehicle including an engine 12 that functions as a power source, a first motor MG1 and a second motor MG2 that are motors functioning as power sources. The vehicle 10 includes a pair of drive wheels 14 and a power transmission device 16. The engine 12 is a well-known internal combustion engine. The first motor MG1 and the second motor MG2 are, for example, rotary electric machines having a motor function and a generator function, and are so-called motor generators. The first motor MG1 and the second motor MG2 are power sources for driving the vehicle 10 and are, for example, three-phase synchronous motors. The first motor MG1 and the second motor MG2 are housed in a case 18 which is a non-rotating member attached to the vehicle body. For example, an axis C1 which is the rotation center line of the first motor MG1 and an axis C2 which is the rotation center line of the second motor MG2 are parallel to each other. For example, when the width in the direction of the axis C1 of the first motor MG1 is shorter than the width in the direction of the axis C2 of the second motor MG2, the first motor MG1 and the second motor MG2 are arranged in the vertical direction and the range occupied by the first motor MG1 in the direction of the axis C1 is within the range occupied by the second motor MG2 in the direction of the axis C2. Thereby, in the direction of the axis C1 (= the direction of the axis C2), the range occupied by the first motor MG1 and the second motor MG2 can be shortened. When the first motor MG1 and the second motor MG2 are not particularly distinguished, they are referred to as the motor MG. Note that the "motor MG" corresponds to the "motor" in the present invention, respectively.

[0012] The power transmission device 16 includes, in the power transmission path between the engine 12 and the pair of drive wheels 14, in the case 18 in order from the engine 12 side, a damper 20, a power split mechanism 40, a drive gear 26, a driven gear 28, a driven shaft 30, a final gear 32, a differential 34 (including a differential ring gear 34a), etc., and these have a well-known configuration. Hereinafter, the power split mechanism 40, the drive gear 26, the driven gear 28, the final gear 32, and the differential 34 will be referred to as "the power split mechanism 40 etc.". The power transmission device 16 includes, in the power transmission path between the second motor MG2 and the pair of drive wheels 14, in the case 18 in order from the second motor MG2 side, a reduction gear 36, a driven gear 28, a driven shaft 30, a final gear 32, a differential 34, etc., and these have a well-known configuration. The power transmission device 16 includes a pair of axles 38 etc. connected to the differential 34. The output of the power transmission device 16 is transmitted to the pair of drive wheels 14 via a pair of axles 38 etc. connected to the differential 34.

[0013] The power split mechanism 40 is composed of a known single pinion type planetary gear device. For example, the power output from the engine 12 is mechanically split by the power split mechanism 40 into the first motor MG1 and the drive gear 26. By the power of the engine 12 split to the first motor MG1, the first motor MG1 generates electricity. The generated power of the first motor MG1 is charged to the high-voltage battery 46 (see FIG. 2), or all or part of the generated power or the power from the high-voltage battery 46 in addition to the generated power is used for the rotational drive of the second motor MG2. The power split mechanism 40 functions as an electric continuously variable transmission in which the differential state of the power split mechanism 40 is controlled by controlling the operating state of the first motor MG1. The power of the engine 12 split to the drive gear 26 is transmitted to the driven gear 28, the driven shaft 30, the final gear 32, and the differential 34. The second motor MG2 is connected to the driven shaft 30 so as to be able to transmit power via the reduction gear 36 and the driven gear 28. Note that the first motor MG1 can also function as a power source that outputs power to the pair of drive wheels 14 via the power split mechanism 40.

[0014] FIG. 2 is a diagram for explaining an example of the electrical configuration of the PCU 54 and the like of the drive unit 80 according to an embodiment of the present invention. Note that the PCU 54 corresponds to the "power control device" in the present invention.

[0015] The vehicle 10 further includes a high-voltage battery 46, an accessory battery 48, and a PCU 54. The high-voltage battery 46 is a rechargeable secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion battery, for example. The high-voltage battery 46 is connected to the PCU 54. The high-voltage battery 46 is a battery for driving the motor MG. For example, the stored power from the high-voltage battery 46 is supplied to the second motor MG2 via the PCU 54. Each motor MG generates electricity by the power of the engine 12 and the driven power input from a pair of drive wheels 14, and the generated power is charged into the high-voltage battery 46 via the PCU 54. The accessory battery 48 is a rechargeable secondary battery such as a lead-acid battery, for example. The accessory battery 48 has a charging voltage lower than that of the high-voltage battery 46. The accessory battery 48 is charged by the generated power of an alternator rotationally driven by the engine 12 or the power supplied from the high-voltage battery 46 via the DCDC converter 56.

[0016] The PCU 54 drives and controls each motor MG. The PCU 54 includes a DCDC converter 56, a boost converter 60, an inverter 62, and a motor control device 58. The PCU 54 is a power control device that controls the power exchanged between the high-voltage battery 46 and the motor MG, that is, the power exchanged by each motor MG.

[0017] The DCDC converter 56 is connected to the high-voltage battery 46. The DCDC converter 56 functions as a charging device that steps down the voltage of the high-voltage battery 46 to a voltage equivalent to that of the accessory battery 48 to charge the accessory battery 48. The accessory battery 48 supplies power for operating the accessories provided in the vehicle 10. The accessory battery 48 supplies power for operating, for example, the engine control device 52 and the motor control device 58.

[0018] The boost converter 60 includes a reactor, switching elements (not shown), etc. The boost converter 60 is a buck-boost circuit having a function of boosting the voltage of the high-voltage battery 46 and supplying it to the inverter 62, and a function of stepping down the voltage converted to direct current by the inverter 62 and supplying it to the high-voltage battery 46.

[0019] The inverter 62 includes an MG1 power module 64, an MG2 power module 66, etc. The MG1 power module 64 and the MG2 power module 66 each include switching elements (not shown). The MG1 power module 64 is connected to the first motor MG1 via a terminal block 84. The MG2 power module 66 is connected to the second motor MG2 via a terminal block 86. The terminal block 84 and the terminal block 86 are each fixed to a partition wall 72d1 and are for connecting connection lines through which a three-phase alternating current for driving the motor MG flows between the upper space U and the lower space L. The partition wall 72d1, the upper space U, and the lower space L will be described later. The lower space L (the motor chamber L1 described later) is sealed in an oil-tight manner by the terminal block 84 and the terminal block 86. The inverter 62 converts the direct current output from the boost converter 60 into an alternating current for driving the motor MG. The inverter 62 converts the alternating current generated by the motor MG into a direct current respectively. The inverter 62 uses the power generated by the first motor MG1 as the power for driving the second motor MG2 according to the running state.

[0020] The electronic control device 50, the engine control device 52, and the motor control device 58 are controllers each including a control device for controlling each part in the vehicle 10, and are configured to include a so-called microcomputer that performs signal processing according to a program stored in a ROM in advance while a CPU uses the temporary storage function of a RAM.

[0021] The electronic control unit 50 transmits and receives signals to and from the DCDC converter 56, the motor control unit 58, and the engine control unit 52 via, for example, a known CAN (Controller Area Network) communication line. The electronic control unit 50 controls the running state of the vehicle 10 based on signals from, for example, sensors (not shown). The electronic control unit 50 steps down the voltage of the high-voltage battery 46 to a voltage equivalent to that of the auxiliary battery 48 by controlling the DCDC converter 56, for example. In this embodiment, the electronic control unit 50 and the engine control unit 52 are separate control units from the PCU 54, particularly the motor control unit 58.

[0022] The motor control unit 58 controls the motor MG based on the output required value from the electronic control unit 50. For example, the motor control unit 58 controls the boost converter 60 and the inverter 62 to control the output of each of the motors MG.

[0023] Returning to FIG. 1. The transaxle 82 is a drive device including the power transmission device 16 (such as the power split mechanism 40), the first motor MG1, and the second motor MG2. Note that the "transaxle 82" corresponds to the "drive device" in the present invention. The drive unit 80 is a unit in which the transaxle 82 and the PCU 54 are housed in the same case 18 and integrated, that is, an electromechanical integrated unit.

[0024] Hereinafter, the meaning of the "same case" will be described. The case 18 is made of, for example, an aluminum alloy casting and includes a first case portion 70, a second case portion 72, a third case portion 74, and a fourth case portion 76.

[0025] The first case part 70 is a bottomed cylindrical member. The first case part 70 has an opening 70o (see FIG. 2) on one side opposite to the cylindrical engine 12. The second case part 72 includes a bottomed cylindrical lower part 72L and a box-shaped upper part 72U, and a partition wall 72d1 is provided between the upper part 72U and the lower part 72L. In the second case part 72, the partition wall 72d1 and the portion above the partition wall 72d1 are the upper part 72U, and the partition wall 72d1 and the portion below the partition wall 72d1 are the lower part 72L. For example, the second case part 72 is integrally formed by casting. The space inside the lower part 72L of the second case part 72 is separated into a cylindrical one side and the other side by a partition wall 72d2. The lower part 72L has an opening 72o1 (see FIG. 2) and an opening 72o2 (see FIG. 2) on one side on the engine 12 side and the other side opposite to the engine 12, respectively. The upper part 72U of the second case part 72 has an opening 72o3 (see FIG. 2) on its upper surface.

[0026] The first case part 70 and the second case part 72 are integrally connected by a fastener such as a bolt 78a so that the opening 70o of the first case part 70 and the opening 72o1 of the lower part 72L of the second case part 72 are blocked from each other. Note that the "opening 70o" and the "opening 72o1" respectively correspond to the "opening of the first case part" and the "one opening of the lower part" in the present invention.

[0027] The third case part 74 is a plate-like member joined to the second case part 72 so as to close the opening 72o2 of the second case part 72. Note that the "opening 72o2" corresponds to the "other lower opening" in the present invention. The second case part 72 and the third case part 74 are integrally connected by a fastener such as a bolt 78b. The opening 70o of the first case part 70 and the opening 72o1 of the lower part 72L are connected by a bolt 78a so as to block each other, and the third case part 74 is connected by a bolt 78b so as to block the opening 72o2 of the lower part 72L. Thus, the interior of the lower part 72L is separated into a motor chamber L1 and a gear chamber L2. Note that the motor chamber L1 is a space surrounded by the third case part 74 and the other side of the lower part 72L on the side opposite to the cylindrical engine 12. The gear chamber L2 is a space surrounded by the first case part 70 and the one side of the lower part 72L on the side of the cylindrical engine 12. The side of the motor chamber L1 on the engine 12 side and the side of the gear chamber L2 opposite to the engine 12 form a common partition wall 72d2.

[0028] The fourth case part 76 is a plate-like member joined to the second case part 72 so as to close the opening 72o3 on the upper surface of the second case part 72. Note that the "opening 72o3" corresponds to the "upper opening" in the present invention. The second case part 72 and the fourth case part 76 are integrally connected by a fastener such as a bolt 78c. Note that the bolts 78a, 78b, and 78c respectively correspond to the "fasteners" in the present invention.

[0029] Here, in case 18, the part surrounding the upper space U is referred to as the upper case part 18U (in this embodiment, the upper part 72U of the second case part 72 and the fourth case part 76), and the part surrounding the lower space L in case 18 is referred to as the lower case part 18L (in this embodiment, the first case part 70, the lower part 72L of the second case part 72, and the third case part 74). In the vertical direction, the lower case part 18L is the part provided on the lower side of the upper case part 18U in case 18. Below the upper case part 18U and above the lower case part 18L is a common partition wall 72d1. For this reason, when the upper case part 18U and the lower case part 18L are separated, at least one of the interiors of the upper case part 18U and the lower case part 18L will necessarily be in a state of being exposed to the outside. The "same case" means a case where at least one of the interiors is exposed to the outside when the upper case part 18U and the lower case part 18L are separated in this way.

[0030] In the state of being mounted on the vehicle 10, the PCU 54 is housed in the upper case part 18U, and the transaxle 82 is housed in the lower case part 18L. Among the transaxle 82, the first motor MG1 and the second motor MG2 are housed in the motor chamber L1, and the power split mechanism 40 and the like are housed in the gear chamber L2. Note that the power split mechanism 40 and the like housed in the gear chamber L2 correspond to the "gear" in the present invention.

[0031] Incidentally, a first resolver 92 and a second resolver 94, which are sensors for detecting the rotational states (such as rotational speed and rotational position) of the first motor MG1 and the second motor MG2 respectively, are arranged in the motor chamber L1. That is, the first resolver 92 and the second resolver 94 are mounted in the motor chamber L1. For example, the first resolver 92 has a well-known configuration including a resolver stator 92s and a resolver rotor 92r. The resolver stator 92s includes a laminated steel plate formed by laminating a plurality of annular electromagnetic steel plates, and a coil portion for rotation detection provided at the inner peripheral edge of the laminated steel plate. The resolver rotor 92r is disposed with a slight gap on the inner peripheral side of the coil portion. The resolver rotor 92r includes a laminated steel plate formed by laminating a plurality of annular electromagnetic steel plates whose outer peripheral surface is elliptical or oblong, and is non-rotatably attached to the rotor of the first motor MG1. For example, the second resolver 94 includes a resolver stator 94s and a resolver rotor 94r, which are the same as the resolver stator 92s and the resolver rotor 92r of the first resolver 92 respectively. The resolver rotor 94r is non-rotatably attached to the rotor of the second motor MG2. In particular, when the first resolver 92 and the second resolver 94 are not particularly distinguished, they are referred to as the resolver 90. Note that the "resolver 90" corresponds to the "resolver" in the present invention respectively. A wire harness 96 is provided between the resolver 90 and the PCU54. The wire harness 96 sends the detection signal from the resolver 90 to the PCU54. Note that the "wire harness 96" corresponds to the "wiring" in the present invention.

[0032] The wire harness 96 extends from the first resolver 92 and the second resolver 94 in the motor chamber L1 in the directions of the axis C1 of the first motor MG1 and the axis C2 of the second motor MG2, respectively. After passing through the partition walls 72d2 respectively, the wire harness 96 is bent toward the direction of the motor control device 58 housed in the upper part 72U in the gear chamber L2. Preferably, the wire harness 96 extends in the direction of the motor control device 58 along the partition wall 72d2 in the gear chamber L2. The wire harness 96 is connected to the motor control device 58 included in the PCU 54 after passing through the opening 88 provided in the partition wall 72d1 (see FIG. 2). An O-ring (not shown) is sandwiched between the opening 88 and the wire harness 96, so that the gear chamber L2 is sealed in an oil-tight manner. Preferably, in the gear chamber L2, the wire harness 96 that sends the detection signals at the first resolver 92 and the second resolver 94 from the first resolver 92 which is the rotation sensor of the first motor MG1 and the second resolver 94 which is the rotation sensor of the second motor MG2 to the PCU 54 are bundled together.

[0033] According to the present embodiment, the wire harness 96 that sends the detection signals at the first resolver 92 and the second resolver 94 from the first resolver 92 which is the rotation sensor of the first motor MG1 and the second resolver 94 which is the rotation sensor of the second motor MG2 to the PCU 54 is arranged only inside the case 18. Compared with the case where the wire harness 96 is arranged outside the case 18, when it is arranged only inside the case 18, the length of the wire harness 96 can be shortened. Thereby, for example, the mountability of the drive unit 80 on the vehicle 10 can be improved and an increase in the cost of the drive unit 80 can be suppressed.

[0034] According to this embodiment, (a) the case 18 has a first case portion 70, a second case portion 72, a third case portion 74, and a fourth case portion 76, (b) the first case portion 70 is a bottomed cylindrical member, (c) the second case portion 72 has a box-shaped upper portion 72U and a cylindrical lower portion 72L, the boundary between the upper portion 72U and the lower portion 72L is a common partition wall 72d1, the opening 70o of the first case portion 70 and one opening 72o1 of the lower portion 72L are connected by bolts 78a so as to be blocked from each other, and the upper portion 72U is a member having an opening 72o3, (d) the third case portion 74 is a member connected by bolts 78b so as to block the other opening 72o2 of the lower portion 72L in the second case portion 72, (e) the fourth case portion 76 is a member connected by bolts 78c so as to block the opening 72o3 of the upper portion 72U in the second case portion 72, (f) the PCU 54 is housed in the upper portion 72U of the second case portion 72, and (g) the first resolver 92, the second resolver 94, and the wire harness 96 are arranged only within the second case portion 72. Since the PCU 54 is housed in the upper portion 72U of the second case portion 72, by intensively arranging the first resolver 92, the second resolver 94, and the wire harness 96 within the second case portion 72, the length of the wire harness 96 can be shortened as compared with the case where this is not done. Thereby, for example, compared with the case where the wire harness 96 is arranged in another case 18 other than the second case portion 72 (for example, within the first case portion 70), connectors and the like for connecting from within the second case portion 72 to within another case 18 are not required, so an increase in the cost for arranging the wire harness 96 is suppressed.

[0035] According to this embodiment, (a) the interior of the lower part 72L is separated into a motor chamber L1 in which the motor MG is housed and a gear chamber L2 in which the power split mechanism 40 and the like are housed by connecting the opening 70o of the first case part 70 and one opening 72o1 of the lower part 72L with bolts 78a so that they block each other and connecting the third case part 74 with bolts 78b so as to block the other opening 72o2 of the lower part 72L, (b) the first resolver 92 and the second resolver 94 are arranged in the motor chamber L1, and (c) the wire harness 96 is connected to the PCU 54 housed in the upper part 72U through the gear chamber L2 from the motor chamber L1. As a result, when the wire harness 96 is arranged only in the second case part 72, the difficulty of arranging the wire harness 96 while avoiding the restrictions due to the arrangement of the first motor MG1 and the second motor MG2 housed in the motor chamber L1, that is, the first motor MG1 and the second motor MG2, is reduced, so that it becomes easy to arrange the wire harness 96 only in the second case part 72.

[0036] Note that what has been described above is an embodiment of the present invention, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art without departing from the gist thereof.

[0037] In the above-described embodiment, the wire harness 96 is connected to the PCU 54 housed in the upper part 72U through the gear chamber L2 from the motor chamber L1, but it is not limited to this. For example, the wire harness 96 may be connected to the PCU 54 housed in the upper part 72U without passing through the gear chamber L2 from the motor chamber L1.

[0038] In the above-described embodiment, the first resolver 92, the second resolver 94, and the wire harness 96 are arranged only in the second case part 72, but it is not limited to this. For example, the wire harness 96 may be arranged in the second case part 72 and the first case part 70.

[0039] In the foregoing embodiment, the drive unit 80 includes two motors, i.e., the first motor MG1 and the second motor MG2, and the rotational states of the first motor MG1 and the second motor MG2 are detected by the first resolver 92 and the second resolver 94, respectively. However, the present invention is not limited thereto. For example, the drive unit 80 may include only one motor, and the rotational state of the motor may be detected by one resolver.

Explanation of Signs

[0040] 18: Case, 26: Drive gear, 28: Driven gear, 32: Final gear, 34: Differential gear, 36: Reduction gear, 40: Power split mechanism, 54: PCU (Power control unit), 70: First case part, 70o: Opening (opening of the first case part), 72: Second case part, 72d1: Partition wall, 72L: Lower part, 72o1: Opening (one of the openings in the lower part), 72o2: Opening (the other opening in the lower part), 72o3: Opening (opening in the upper part), 72U: Upper part, 74: Third case part, 76: Fourth case part, 78a - 78c: Bolt (fastener), 80: Drive unit, 82: Transaxle (drive device), 92: First resolver, 94: Second resolver, 96: Wire harness, L1: Motor chamber, L2: Gear chamber, MG1: First motor, MG2: Second motor

Claims

1. A drive unit in which a drive device including a motor and a gear and a power control device for controlling the power transmitted and received by the motor are housed in the same case, wherein a wiring for sending a detection signal from a resolver, which is a rotation sensor of the motor, to the power control device is arranged only inside the case. A drive unit characterized by the above.

2. The case has a first case part, a second case part, a third case part, and a fourth case part, wherein the first case part is a bottomed cylindrical member, the second case part has a box-shaped upper part and a cylindrical lower part, a boundary between the upper part and the lower part is a common partition wall, an opening of the first case part and an opening of one of the lower parts are connected by a fastener so as to be blocked from each other, and the upper part is a member having an opening, the third case part is a member connected by a fastener so as to block the other opening of the lower part in the second case part, the fourth case part is a member connected by a fastener so as to block the opening of the upper part in the second case part, the power control device is housed inside the upper part in the second case part, the resolver and the wiring are arranged only inside the second case part. The drive unit according to claim 1, characterized by the above.

3. By connecting the opening of the first case part and the opening of one of the lower parts by a fastener so as to be blocked from each other and connecting the third case part by a fastener so as to block the other opening of the lower part, the inside of the lower part is separated into a motor chamber in which the motor is housed and a gear chamber in which the gear is housed, the resolver is arranged in the motor chamber, the wiring is connected to the power control device housed inside the upper part through the gear chamber from the motor chamber. The drive unit according to claim 2, characterized by the above.

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