drive unit

Abstract

A drive unit includes an electric unit comprising: a first electric motor for driving; a reduction mechanism that transmits the rotational torque of the first electric motor to a drive wheel; a second electric motor that generates electricity by being driven by an internal combustion engine; and a speed-increasing mechanism that transmits the rotational torque of the internal combustion engine to the second electric motor. The first electric motor, the reduction mechanism, the second electric motor, and the speed-increasing mechanism are housed in a housing. Within the housing, the first electric motor and the second electric motor are arranged parallel to each other in the longitudinal direction of the vehicle body. The reduction mechanism and the speed-increasing mechanism are also arranged in the longitudinal direction of the vehicle body. The electric unit is connected to the internal combustion engine in a left-right direction of the vehicle body. The first rotating shaft, serving as the rotating shaft of the first electric motor, and the second rotating shaft, serving as the rotating shaft of the second electric motor, are located at the front and rear sides of the vehicle body in the longitudinal direction, separated by a crankshaft rotating shaft, which serves as the rotating shaft of the internal combustion engine.

Description

Technical Field

[0001] This invention relates to a drive unit for a series hybrid vehicle. Background Technology

[0002] JP2017-216804A discloses a drive unit for a vehicle, comprising: a generator having a first housing fixed to a transmission; and a drive unit having a second housing fixed to the transmission, the drive unit being fixed to an engine. In this drive unit where the generator and drive unit are housed in separate housings, the following problem exists: the two housings vibrate independently, and the vibration increases due to bending, torsion, etc., of the generator and drive unit. Furthermore, the two vibration sources are close together, making resonance easily occur. To solve these problems, the aforementioned document utilizes a connecting component to join the first housing and the second housing. Summary of the Invention

[0003] However, the drive device disclosed in the above-mentioned documents only connects a portion of the first housing and a portion of the second housing, which vibrate differently, thus limiting the effect of vibration suppression.

[0004] Therefore, the object of the present invention is to provide a drive unit that further improves the effect of vibration suppression.

[0005] According to one aspect of the present invention, a drive unit is provided, comprising an electric unit having: a first electric motor for driving; a reduction mechanism that transmits the rotational torque of the first electric motor to a drive wheel; a second electric motor that is driven by an internal combustion engine to generate electricity; and a speed-increasing mechanism that transmits the rotational torque of the internal combustion engine to the second electric motor. In this drive unit, the first electric motor, the reduction mechanism, the second electric motor, and the speed-increasing mechanism are housed in a single housing. Within the housing, the first electric motor and the second electric motor are arranged parallel to each other in the longitudinal direction of the vehicle body, and the reduction mechanism and the speed-increasing mechanism are also arranged in the longitudinal direction of the vehicle body. Furthermore, the electric unit is connected to the internal combustion engine in a left-right direction of the vehicle body, with the first rotating shaft (serving as the rotating shaft of the first electric motor) and the second rotating shaft (serving as the rotating shaft of the second electric motor) located at the front and rear sides of the vehicle body in the longitudinal direction, separated by a crankshaft rotating shaft (serving as the rotating shaft of the crankshaft of the internal combustion engine). Attached Figure Description

[0006] Figure 1 This is a schematic diagram of the drive unit as viewed from above the vehicle body while it is in vehicle mode.

[0007] Figure 2 It is an exploded perspective view of the electric unit contained in the drive unit.

[0008] Figure 3 From Figure 2 Side view of the electric motor unit viewed in the direction of arrow III. Detailed Implementation

[0009] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0010] Figure 1 This is a schematic structural diagram of the drive unit 100 involved in this embodiment, viewed from above the vehicle body in a vehicle-mounted state. Figure 2 This is an exploded perspective view of the electric unit 100a included in the drive unit 100. Figure 3 From Figure 2 Side view of electric unit 100a viewed in the direction of arrow III.

[0011] In the following description, the direction of vehicle travel is set as "forward", the opposite direction is set as "rear", the left side facing the direction of vehicle travel is set as "left", the right side facing the direction of vehicle travel is set as "right", the upper side facing the direction of vehicle travel is set as "up", and the lower side facing the direction of vehicle travel is set as "down".

[0012] The drive unit 100 includes an internal combustion engine 1 and an electric unit 100a (described later). The crankshaft 1a of the internal combustion engine 1 is configured with an orientation consistent with the left-right direction of the vehicle body. The electric unit 100a and the internal combustion engine 1 are arranged in the left-right direction of the vehicle body. The internal combustion engine 1 and the electric unit 100a are fastened together by bolts or the like. In addition, auxiliary components 6 are mounted on the internal combustion engine 1. The auxiliary components 6 are, for example, an oil cooler, a compressor for an air conditioning system, etc.

[0013] The fixed internal combustion engine 1 and electric unit 100a (i.e., drive unit 100) are supported on the vehicle body from the left and right directions by pendulum-type brackets 2a and 2b. Here, the support parts of each of the brackets 2a and 2b are designated as 3a and 3b. In addition to the brackets 2a and 2b, a torque rod (not shown) can also be provided to support the drive unit 100 from the front and rear directions of the vehicle body.

[0014] Here, refer to Figure 2 The structure of the electric unit 100a will be described.

[0015] The housing H of the electric unit 100a is composed of the following components: an outer housing 10; a gear cover 11, which is mounted at one end of the outer housing 10; and a rear cover 12, which is mounted at the other end of the outer housing 10.

[0016] The outer casing 10 includes a first cylindrical portion (not shown) that houses the drive motor 15, and a second cylindrical portion (not shown) that houses the generator motor 17. The first and second cylindrical portions are each formed in a cylindrical shape and are arranged in the outer casing 10 such that their axes are parallel to each other. The drive motor 15, which is the first electric motor, is housed in the first cylindrical portion via the inner casing 14, and the generator motor 17, which is the second electric motor, is housed in the second cylindrical portion via the inner casing 16. Furthermore, comparing the drive motor 15 and the generator motor 17, the drive motor 15, requiring a larger output, is heavier than the generator motor 17.

[0017] The drive motor 15 includes a rotor 15a, which is rotatably supported on the rear cover 12; and a stator (not shown), which is fixed inside the inner housing 14. The generator motor 17 includes a rotor 17a, which is rotatably supported on the rear cover 12; and a stator (not shown), which is fixed inside the inner housing 16. The inner housings 14 and 16 and the rear cover 12 are fixed to the outer housing 10 by bolts or the like, and the rotors 15a and 17a and the stator are fixed in opposite positions.

[0018] An inverter 13 is mounted on the upper part of the housing 10. The inverter 13 has a first power module 40 and a second power module 41 constituting an inverter circuit. Here, "upper part" refers to the portion above the plane including the first rotating shaft 15b, which serves as the rotating shaft of the drive motor 15, and the second rotating shaft 17b, which serves as the rotating shaft of the generator motor 17. Furthermore, in this embodiment, as described later... Figure 3 As shown, the electric unit 100a is mounted on the vehicle with its plane P, including the first rotating shaft 15b and the second rotating shaft 17b, tilted relative to the horizontal direction. More specifically, the electric unit 100a is mounted on the vehicle with the drive motor 15 positioned higher than the generator motor 17.

[0019] The gear chamber G, formed by the outer shell 10 and the gear cover 11, houses: a reduction mechanism 18 connected to the rotating shaft 15b of the drive motor 15; and a speed-increasing mechanism 19 connected to the rotating shaft 17b of the generator motor 17.

[0020] The reduction mechanism 18 consists of three gears, which reduce the rotation of the drive motor 15's rotating shaft 15b to the drive wheel (not shown). The output shaft 5 of the reduction mechanism 18 is connected to the drive wheel via a drive shaft (not shown). The output shaft 5 is arranged orthogonally to the vehicle's direction of travel, depending on its nature. Furthermore, the rotating shafts of each gear in the reduction mechanism 18, as well as the first rotating shaft 15b that inputs rotation to the reduction mechanism 18, are parallel to the output shaft 5. Additionally, a second rotating shaft 17b, which is parallel to the first rotating shaft 15b, is also parallel to the output shaft 5. Moreover, the crankshaft 1a of the internal combustion engine 1, which is connected to the second rotating shaft 17b via the speed-increasing mechanism 19, is also parallel to the output shaft 5.

[0021] The speed-increasing mechanism 19 increases the rotational speed of the crankshaft 1a of the internal combustion engine 1 and transmits this speed to the generator 17. Furthermore, in this embodiment, the speed-increasing mechanism 19 is exemplified as such. Figure 3 The mechanism shown is based on sprockets and chains, but it can also be a mechanism consisting of two gears.

[0022] Furthermore, if we compare the deceleration mechanism 18 with the speed-increasing mechanism 19, the deceleration mechanism 18, which consists of three gears, is heavier than the speed-increasing mechanism 19, which consists of two sprockets and a chain or two gears.

[0023] As described above, the electric unit 100a of this embodiment comprises four components: a drive motor 15, a speed-increasing mechanism 19, a generator motor 17, and a speed-reducing mechanism 18, all housed within a single housing H. Furthermore, an inverter 13 is mounted within the housing H.

[0024] Return to Figure 1 Explanation.

[0025] The crankshaft rotation axis 1b is parallel to the bracket connecting line Amt that connects the support portions 3a and 3b of the two brackets 2a and 2b, and as shown in the figure. Figure 3 The figure shown is located on the vertical plane S, including the support connecting line Amt. The support connecting line Amt is also parallel to the output shaft 5 of the reduction mechanism 18.

[0026] Regarding the drive unit 100 in vehicle mode, the first rotating shaft 15b and the second rotating shaft 17b are located at the front and rear sides of the vehicle body in the longitudinal direction, separated by the rotating shaft (also called the crankshaft rotating shaft) 1b of the crankshaft 1a.

[0027] More specifically, the drive motor 15 is positioned further rearward than the crankshaft rotation axis 1b, and the generator motor 17 is positioned further forward than the crankshaft rotation axis 1b. Correspondingly, the reduction mechanism 18 is positioned further rearward than the crankshaft rotation axis 1b, and the speed-increasing mechanism 19 is positioned further forward than the crankshaft rotation axis 1b. As mentioned above, the drive motor 15 is heavier than the generator motor 17, and the reduction mechanism 18 is heavier than the speed-increasing mechanism 19. Therefore, the center of gravity of the electric unit 100a is positioned further rearward than the crankshaft rotation axis 1b. Therefore, the auxiliary component 6 is positioned further forward than the crankshaft rotation axis 1b so that the center of gravity of the drive unit 100a, when viewed from above the vehicle body, is located on the bracket connection line Amt. This helps to suppress vibration. The choice of which component, such as the oil cooler or the air conditioning compressor, is designated as the auxiliary component 6 is appropriately determined based on the weight difference between the drive motor 15 and the generator motor 17, and the weight difference between the reduction mechanism 18 and the speed-increasing mechanism 19.

[0028] Here, refer to Figure 3 The positional relationship between the first rotating shaft 15b, the second rotating shaft 17b, and the crankshaft rotating shaft 1b is explained in more detail. Figure 3 From Figure 2 The diagram shows the housing H of the electric unit 100a viewed along the direction of arrow III (i.e., the left-right direction of the vehicle body).

[0029] exist Figure 3 In this configuration, the crankshaft rotation axis 1b is located on the motor connection line Amg passing through the first rotation axis 15b and the second rotation axis 17b, and is located at the midpoint between the first rotation axis 15b and the second rotation axis 17b. Furthermore, it is preferable that the motor connection line Amg is inclined at 45° relative to the horizontal plane.

[0030] This arrangement, with the drive motor 15 and generator motor 17 tilted relative to the horizontal plane, suppresses the longitudinal dimension of the drive unit 100. A 45° tilt is preferred because it allows for suppression of both the longitudinal and longitudinal dimensions of the drive unit 100 and the vertical dimension. Specifically, if the tilt is greater than 45°, the longitudinal dimension is further suppressed, but the vertical dimension increases compared to the 45° case; conversely, if the tilt is less than 45°, the vertical dimension is further suppressed, but the longitudinal dimension increases compared to the 45° case. In contrast, a 45° tilt allows for suppression of both the longitudinal and vertical dimensions.

[0031] Furthermore, the electric motor unit 100a is housed within a housing H, thus vibrating as a single unit. This structure allows for the suppression of both vertical and horizontal vibrations of the electric motor unit 100a. Specifically, if the slope is greater than 45°, vertical vibrations are further suppressed, but front-back vibrations increase compared to the 45° case. Conversely, if the slope is less than 45°, front-back vibrations are further suppressed, but vertical vibrations increase compared to the 45° case. And if the slope is 45°, both vertical and front-back vibrations are suppressed.

[0032] Next, the effects of making the drive unit 100 form the structure of this embodiment will be explained.

[0033] In this embodiment, a drive unit 100 is provided, which includes an electric unit comprising: a drive motor 15; a reduction mechanism 18 that transmits the rotational torque of the drive motor 15 to the drive wheel; a generator motor 17 that is driven by an internal combustion engine 1 to generate electricity; and a speed-increasing mechanism 19 that transmits the rotational torque of the internal combustion engine 1 to the generator motor 17. Regarding this drive unit 100, the drive motor 15, the reduction mechanism 18, the generator motor 17, and the speed-increasing mechanism 19 are housed in a housing H. Within the housing H, the rotational axes of the drive motor 15 and the generator motor 17 are arranged in parallel in the longitudinal direction of the vehicle body, and the reduction mechanism 18 and the speed-increasing mechanism 19 are also arranged in the longitudinal direction of the vehicle body. Furthermore, the electric unit 100a and the internal combustion engine 1 are connected in a configuration that runs horizontally along the vehicle body. The first rotating shaft 15b, which serves as the rotating shaft of the drive motor 15, and the second rotating shaft 17b, which serves as the rotating shaft of the generator motor 17, are located at the front and rear sides of the vehicle body, separated by the crankshaft rotating shaft 1b, which serves as the rotating shaft of the crankshaft 1a of the internal combustion engine 1. As described above, by housing the drive motor 15 and the generator motor 17, which are the main vibration sources of the electric unit 100a, within a housing H, it is possible to suppress the vibration of the drive motor 15 and the generator motor 17 in different modes. Additionally, the first rotating shaft 15b and the second rotating shaft 17b are positioned further forward and rearward than the crankshaft rotating shaft 1b of the internal combustion engine 1, which is the heaviest component of the drive unit 100, respectively, thereby placing the center of gravity of the drive unit 100 between the first rotating shaft 15b and the second rotating shaft 17b. This further suppresses the vibration of the drive unit 100.

[0034] In this embodiment, the electric unit 100a and the internal combustion engine 1, in a connected state, are supported on the vehicle body from the left-right direction by pendulum-type brackets 2a and 2b. The bracket connection line Amt is parallel to the output shaft 5 of the reduction mechanism 18. This bracket connection line Amt is the line connecting the support portion 3a of the left side of the bracket 2a in the left-right direction to the support portion 3b of the right side of the bracket 2b in the left-right direction. Therefore, the crankshaft rotation shaft 1b, the first rotation shaft 15b, the second rotation shaft 17b, and the output shaft 5 are parallel to the bracket connection line Amt. When the aforementioned rotation shafts are not parallel to the bracket connection line Amt, the vibration of the drive unit 100 is transmitted to the vehicle body as so-called torsional vibration, generating undesirable vibrations in the vehicle body. In contrast, according to the structure of this embodiment, torsional vibration can be suppressed.

[0035] Furthermore, the reasons why the support connection line Amt can be made parallel to each axis 1b, 15b, 17b, 5 are as follows.

[0036] Based on the viewpoint of suppressing the torque around the support portion 3b, it is preferable that the position of the support portion 3b of the bracket 2b supporting the internal combustion engine 1 in the vehicle body longitudinal direction is close to the center of gravity of the internal combustion engine 1 in the vehicle body lateral direction. On the other hand, based on the viewpoint of suppressing the torque around the support portion 3b, it is preferable that the position of the support portion 3a of the bracket 2a supporting the electric unit 100a in the vehicle body longitudinal direction is close to the center of gravity of the electric unit 100a in the vehicle body lateral direction. However, the generator motor 17 needs to be connected to the internal combustion engine 1 via the speed-increasing mechanism 19, and the drive motor 15 and the reduction mechanism 18 need to be configured to avoid interference with the generator motor 17 and the speed-increasing mechanism 19. Therefore, with the current structure in which the drive motor 15 and the generator motor 17 are housed in different housings, the dimensional deviation between the electric unit 100a and the internal combustion engine 1 in the vehicle body longitudinal direction increases, making it difficult to make the bracket connection line Amt parallel to each axis 1b, 15b, 17b, 5.

[0037] In this respect, in this embodiment, the drive motor 15 and the generator motor 17 are housed in the housing 10, thereby reducing the size of the electric unit 100a in the front-rear direction of the vehicle body compared to the case where each motor is housed in a different housing.

[0038] Furthermore, when connecting the internal combustion engine 1, the speed-increasing mechanism 19, and the generator 17, in the current structure where the speed-increasing mechanism 19 and the generator 17 are housed in separate housings, to avoid interference between the components in the longitudinal direction of the vehicle body, the speed-increasing mechanism 19 is composed of three gears. That is, it is formed with three gears arranged in the longitudinal direction of the vehicle body. In contrast, in this embodiment, the speed-increasing mechanism 19 and the generator 17 are housed in the housing 10, thus increasing the degree of freedom in the layout, and the speed-increasing mechanism 19 can be composed of two sprockets and a chain or two gears as described above. As a result, compared to the case where the speed-increasing mechanism 19 is composed of three gears, the longitudinal dimension of the electric unit 100a in the longitudinal direction of the vehicle body is reduced.

[0039] Furthermore, in this embodiment, the inverter 13 is also housed within the housing 10. If the inverter 13 is housed in a different housing (inverter housing) than the drive motor 15, and this housing is mounted on the housing (motor housing) that houses the drive motor 15, the inverter housing protrudes from the motor housing, easily increasing the overhang in the longitudinal direction of the vehicle body. In contrast, with the structure in this embodiment where the inverter 13 is also housed within the housing 10, the aforementioned overhang in the longitudinal direction of the vehicle body can be suppressed.

[0040] In this embodiment, the front-rear dimensions and overhang of the vehicle body are suppressed as described above, so that the front-rear position of the support portion 3a of the bracket 2a can be set to a position suitable for supporting the electric unit 100a, and the bracket connection line Amt can be made parallel to each axis 1b, 15b, 17b, 5.

[0041] In this embodiment, the crankshaft rotation axis 1b is parallel to the bracket connection line Amt and lies on the vertical plane S including the bracket connection line Amt. The crankshaft rotation axis 1b of the internal combustion engine 1, which is the heaviest component in the drive unit 100, lies on the vertical plane S including the bracket connection line Amt, thereby suppressing the vibration of the drive unit 100 with the support parts 3a and 3b as fulcrums.

[0042] In this embodiment, the drive motor 15 is heavier than the generator motor 17, and the speed-increasing mechanism 19 is heavier than the speed-reducing mechanism 18. The drive motor 15 and the speed-reducing mechanism 18 are positioned further rearward than the crankshaft rotation axis 1b, while the generator motor 17 and the speed-increasing mechanism 19 are positioned further forward than the crankshaft rotation axis 1b. Furthermore, at least a portion of the multiple auxiliary components 6 of the internal combustion engine 1 are positioned further forward than the crankshaft rotation axis 1b, thereby ensuring that the center of gravity of the entire drive unit 100 is located on the bracket connection line Amt. This allows for adjustment of the balance under the support of brackets 2a and 2b, further suppressing vibration of the entire drive unit 100.

[0043] In this embodiment, when viewed from the left-right direction of the vehicle body, the crankshaft rotation axis 1b is located at the midpoint of the motor connection line Agg, which serves as the line connecting the first rotation axis 15b and the second rotation axis 17b, and the motor connection line Agg is inclined at 45 degrees relative to the horizontal plane. This allows for the suppression of both the longitudinal and longitudinal dimensions of the drive unit 100 and the vertical dimensions.

[0044] The embodiments of the present invention have been described above, but the above embodiments only illustrate a part of the application examples of the present invention, and their purpose is not to limit the technical scope of the present invention to the specific structures of the above embodiments.

Claims

1. A drive unit comprising an electric unit, the electric unit having: a first electric motor for driving; a reduction mechanism for transmitting the rotational torque of the first electric motor to a drive wheel; a second electric motor driven by an internal combustion engine to generate electricity; and a speed-increasing mechanism for transmitting the rotational torque of the internal combustion engine to the second electric motor, wherein, The first electric motor, the reduction mechanism, the second electric motor, and the speed-increasing mechanism are housed in a single housing. Within the housing, the first electric motor and the second electric motor are arranged parallel to each other in the longitudinal direction of the vehicle body. The deceleration mechanism and the speed-increasing mechanism are arranged in the front-rear direction of the vehicle body. The electric unit and the internal combustion engine are connected in a configuration that is arranged in the left-right direction of the vehicle body. The first rotating shaft, which serves as the rotating shaft of the first electric motor, and the second rotating shaft, which serves as the rotating shaft of the second electric motor, are located at the front and rear sides of the vehicle body in the longitudinal direction, separated by the crankshaft rotating shaft, which serves as the rotating shaft of the internal combustion engine. When viewed from the left and right sides of the vehicle body, the crankshaft rotation axis is located at the midpoint of the motor connection line, which serves as the line connecting the first rotation axis and the second rotation axis.

2. The driving unit according to claim 1, wherein, In the connected state, the electric unit and the internal combustion engine are supported on the vehicle body from the left and right directions by pendulum-type brackets. The bracket connection line is parallel to the output shaft of the reduction mechanism. This bracket connection line connects the support portion of the bracket on the left side of the vehicle body in the left-right direction to the support portion of the bracket on the right side of the vehicle body in the left-right direction.

3. The driving unit according to claim 2, wherein, The crankshaft rotation axis is parallel to the support connection line and lies on the plumb plane including the support connection line.

4. The driving unit according to claim 3, wherein, The first motor is heavier than the second motor, and the speed-increasing mechanism is heavier than the speed-reducing mechanism. The first electric motor and the reduction mechanism are configured to be located further rearward than the crankshaft rotation axis of the vehicle body, the second electric motor and the speed-increasing mechanism are configured to be located further forward than the crankshaft rotation axis of the vehicle body, and at least a portion of the plurality of auxiliary components of the internal combustion engine are configured to be located further forward than the crankshaft rotation axis of the vehicle body, thereby making the center of gravity of the entire drive unit located on the support connection line.

5. The driving unit according to claim 4, wherein, When viewed from the left and right sides of the vehicle body, the motor connection line is tilted at 45 degrees relative to the horizontal plane.

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