Hybrid vehicle

Abstract

To provide a hybrid vehicle, which is configured so that total physical sizes of an engine and devices of a power train can be suppressed from enlarging.SOLUTION: In a hybrid vehicle 10, an engine 12 and a first electric motor MG1 are arranged rotatably around a first shaft line CL1 (a), a second electric motor MG2, a speed reduction mechanism 42 and a differential gear 44 are arranged rotatably around a second shaft line CL2 that is parallel to the first shaft line CL1 (b), the second electric motor MG2, a first planetary gear device 42a, a second planetary gear device 42b and the differential gear 44 are arranged in this order from the first electric motor MG1 side toward the engine 12, in a direction of the second shaft line CL2 (c), and a second rotor shaft 40 is connected to a sun gear S1 of the first planetary gear device 42a, a ring gear R1 of the first planetary gear device 42a is connected to a sun gear S2 of the second planetary gear device 42b, and a carrier CA2 of the second planetary gear device 42b is connected to the differential gear 44 (d).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hybrid vehicle equipped with an engine, a first electric motor and a second electric motor that are rotationally driven by the engine, a reduction mechanism that reduces the power of the second electric motor, and a differential gear to which power is transmitted from the reduction mechanism. [Background technology]

[0002] Hybrid vehicles are known that include an engine, a first electric motor and a second electric motor that are rotationally driven by the engine, a reduction mechanism that reduces the power of the second electric motor, and a differential gear to which power is transmitted from the reduction mechanism. For example, the hybrid vehicle described in Patent Document 1 includes: (a) the engine and the first electric motor are rotatably arranged about a first axis; (b) the second electric motor, the reduction mechanism, and the differential gear are rotatably arranged about a second axis that is parallel to the first axis; and (c) the second electric motor, the reduction mechanism, and the differential gear are arranged in this order along the second axis from the first electric motor side toward the engine side. The hybrid vehicle described in Patent Document 1 also includes a stepped-pinion planetary gear set as the reduction mechanism. A "stepped pinion type planetary gear device" is a planetary gear device that has a large diameter pinion and a small diameter pinion that rotate but cannot rotate relative to each other, with power input to the large diameter pinion from a sun gear that meshes with it, and power output from a carrier to the small diameter pinion that meshes with a ring gear fixed to a non-rotating member. A stepped pinion type planetary gear device is a reduction mechanism that makes it easy to increase the reduction ratio and is less likely to reduce power transmission efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-79981 Summary of the Invention [Problem to be solved by the invention]

[0004] While an increase in the axial length of a stepped pinion planetary gear set is easily suppressed, its outer diameter relative to the axis tends to increase. Therefore, when an engine projecting radially about a first axis and a stepped pinion planetary gear set projecting radially about a second axis are arranged in a position where they overlap in the first axis direction (i.e., the same direction as the second axis direction), the distance between the first and second axes may need to be increased to position the engine and the stepped pinion planetary gear set so that they do not physically overlap. Increasing the distance between the first and second axes increases the overall size of the engine rotatably disposed about the first axis and the powertrain components rotatably disposed about the second axis. This can, for example, deteriorate the aerodynamic characteristics of the vehicle or reduce the freedom of vehicle design.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a hybrid vehicle that can prevent the overall size of the engine and each device in the powertrain from becoming too large. [Means for solving the problem]

[0006] The gist of the present invention is a hybrid vehicle including an engine, a first electric motor driven by the engine, a second electric motor, a speed reduction mechanism that reduces the power of the second electric motor, and a differential gear to which power is transmitted from the speed reduction mechanism, wherein (a) the engine and the first electric motor are arranged to be rotatable about a first axis, (b) the speed reduction mechanism includes a first planetary gear set and a second planetary gear set, and (c) the second electric motor, the first planetary gear set, the second planetary gear set, and the differential gear are arranged to be rotatable about a first axis, (d) the second electric motor, the first planetary gear set, the second planetary gear set, and the differential gear are arranged in this order from the first electric motor side toward the engine side in the second axial direction; (e) the output shaft of the second electric motor is connected to the sun gear of the first planetary gear set, the ring gear of the first planetary gear set is connected to the sun gear of the second planetary gear set, and the carrier of the second planetary gear set is connected to the differential gear. [Effects of the Invention]

[0007] According to the present invention, (a) the engine and the first electric motor are each rotatably arranged about a first axis, (b) the reduction mechanism includes a first planetary gear set and a second planetary gear set, (c) the second electric motor, the first planetary gear set, the second planetary gear set, and the differential gear are each rotatably arranged about a second axis parallel to the first axis, (d) in the second axial direction, the second electric motor, the first planetary gear set, the second planetary gear set, and the differential gear are arranged in this order from the first electric motor side to the engine side, and (e) the output shaft of the second electric motor is connected to the sun gear of the first planetary gear set, the ring gear of the first planetary gear set is connected to the sun gear of the second planetary gear set, and the carrier of the second planetary gear set is connected to the differential gear. The configuration of (e) above increases the reduction ratio of the reduction mechanism including the first planetary gear set and the second planetary gear set, while suppressing an increase in its outer diameter relative to the second axis. In this way, an increase in the outer diameter of the reduction mechanism relative to the second axis is suppressed, and the arrangement of (d) above facilitates reducing the outer diameter of each device of the power train that is arranged to protrude from the first electric motor side toward the engine side in the second axial direction and is arranged to be rotatable about the second axis. This allows the engine that is rotatable about the first axis and each device of the power train that is rotatable about a second axis parallel to the first axis to be arranged while suppressing an increase in the axial distance between the first axis and the second axis. In other words, an increase in the overall size of the engine and each device of the power train is suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a schematic configuration diagram of a hybrid vehicle according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a schematic configuration diagram of a hybrid vehicle according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. Note that unless otherwise specified, the drawings have been appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily accurately depicted. [Example]

[0010] Fig. 1 is a schematic diagram of a hybrid vehicle 10 (hereinafter simply referred to as "vehicle 10") according to a first embodiment of the present invention. In Fig. 1, arrows indicate the upper and lower sides of the vehicle 10 in the direction of a vertical line, and the left and right sides in the vehicle width direction. Fig. 1 is a view of the vehicle 10 as seen from the rear to the front.

[0011] The vehicle 10 includes an engine 12, a crankshaft 30, a damper 14, an input shaft 32, a power split mechanism 20, a first electric motor MG1, a countershaft 26, a second electric motor MG2, a reduction mechanism 42 including a first planetary gear set 42a and a second planetary gear set 42b, a differential gear 44, a pair of axles 48, and a pair of drive wheels 50. The reduction mechanism 42 reduces the power output from the second electric motor MG2 and outputs it to the differential gear 44. The damper 14, the input shaft 32, the power split mechanism 20, the first electric motor MG1, the countershaft 26, the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are housed within a transaxle case 16. In FIG. 1, the devices shown within the transaxle case 16 are shown reflecting their relative vertical and horizontal positional relationships.

[0012] The engine 12, the damper 14, the input shaft 32, the power split mechanism 20, and the first electric motor MG1 are each arranged to be rotatable about a first axis CL1.

[0013] The engine 12 is a well-known internal combustion engine. The damper 14 is a well-known device that absorbs fluctuations in the power input from the crankshaft 30 of the engine 12 and outputs the power to the input shaft 32. In this specification, unless otherwise specified, the terms power, driving force, force (= power), and torque are synonymous.

[0014] The first electric motor MG1 and the second electric motor MG2 are rotating electric machines that function as an electric motor and as a generator, that is, so-called motor generators, and have a well-known configuration.

[0015] The power split mechanism 20 is a well-known power split mechanism configured, for example, with a well-known single-pinion planetary gear set. In the planetary gear set constituting the power split mechanism 20, a first rotor shaft 34 which is the rotor shaft of the first electric motor MG1 is connected to the sun gear S0, the engine 12 is connected to the carrier CA0 via the input shaft 32 and the damper 14, and the counter drive gear 22 is connected to the ring gear R0. The planetary gear set constituting the power split mechanism 20 corresponds to the "third planetary gear set" in the present invention. The sun gear S0 corresponds to the "sun gear of the third planetary gear set" in the present invention. The carrier CA0 corresponds to the "carrier of the third planetary gear set" in the present invention.

[0016] The power output from the engine 12 passes through the damper 14 and the input shaft 32 and is mechanically split by the power split mechanism 20 to the first electric motor MG1 and the counter drive gear 22. The first electric motor MG1 is rotationally driven by the power of the engine 12 split to the first electric motor MG1 by the power split mechanism 20. For example, the first electric motor MG1 generates electricity by the power of the engine 12 split to the first electric motor MG1. The power split mechanism 20 functions as an electric continuously variable transmission in which the differential state of the power split mechanism 20 is controlled by controlling the operating state of the first electric motor MG1. The electric power generated by the first electric motor MG1 is used to charge a battery (not shown) or to drive the second electric motor MG2.

[0017] The second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, the differential gear 44, and the pair of axles 48 are each arranged to be rotatable about a second axis line CL2. The second axis line CL2 is parallel to the first axis line CL1. Because the first axis line CL1 and the second axis line CL2 are parallel, the direction of the first axis line CL1 and the direction of the second axis line CL2 are the same. The second axis line CL2 passes directly below the engine 12. In the direction of the second axis line CL2, the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged in this order from the first electric motor MG1 side to the engine 12 side. In this way, in the direction of the second axis CL2 (= the same direction as the direction of the first axis CL1), the engine 12, damper 14, power split mechanism 20, and first electric motor MG1 are arranged in that order from one side to the other, and the second electric motor MG2, first planetary gear set 42a, second planetary gear set 42b, and differential gear 44 are arranged in that order from the other side to the one side.

[0018] The first electric motor MG1 and the second electric motor MG2 are arranged at positions where they overlap with each other in the direction of the second axis CL2. That is, when viewed in a radial direction about the second axis CL2, the second electric motor MG2 is arranged at a position where it overlaps with the first electric motor MG1. In this embodiment, the second electric motor MG2 is arranged directly below the first electric motor MG1. The engine 12, the second planetary gear set 42b, and the differential gear 44 are arranged at positions where they overlap with each other in the direction of the second axis CL2. That is, when viewed in a radial direction about the second axis CL2, the second planetary gear set 42b and the differential gear 44 are arranged at positions where they overlap with the engine 12. In this embodiment, the second planetary gear set 42b and the differential gear 44 are arranged directly below the engine 12. That is, the second planetary gear set 42b constituting a part of the speed reduction mechanism 42 and the differential gear 44 are disposed protruding directly below the engine 12 in the direction of the second axis CL2.

[0019] The sun gear S1 of the first planetary gear device 42a is connected to the second rotor shaft 40 which is the rotor shaft of the second motor MG2. The second rotor shaft 40 corresponds to the "output shaft of the second motor" in the present invention. The sun gear S1 corresponds to the "sun gear of the first planetary gear device" in the present invention. A non-rotating member (for example, the transaxle case 16) is connected to the carrier CA1 of the first planetary gear device 42a. The ring gear R1 of the first planetary gear device 42a is connected to the sun gear S2 of the second planetary gear device 42b and meshes with a counter driven gear 36 described later via an outer peripheral gear 38. The ring gear R1 corresponds to the "ring gear of the first planetary gear device" in the present invention. The outer peripheral gear 38 is a gear provided on the outer peripheral portion of the ring gear R1. The sun gear S2 corresponds to the "sun gear of the second planetary gear device" in the present invention. The carrier CA2 of the second planetary gear device 42b is connected to a differential case which is a case portion of the differential gear 44. The carrier CA2 corresponds to the "carrier of the second planetary gear device" in the present invention. A non-rotating member (for example, the transaxle case 16) is connected to the ring gear R2 of the second planetary gear device 42b. Thus, by connecting the second motor MG2, the first planetary gear device 42a, the second planetary gear device 42b, and the differential gear 44, the reduction ratios of the first planetary gear device 42a and the second planetary gear device 42b are increased while suppressing an increase in the outer diameter with respect to the second axis CL2.

[0020] For example, the outer diameter D2 [mm] of the first planetary gear device 42a (< D1) is smaller than the outer diameter D1 [mm] of the second motor MG2, the outer diameter D3 [mm] of the second planetary gear device 42b (< D2) is smaller than the outer diameter D2 of the first planetary gear device 42a, and the outer diameter D4 [mm] of the differential gear 44 (< D3) is smaller than the outer diameter D3 of the second planetary gear device 42b. Thus, in the direction of the second axis CL2, from the side of the first motor MG1 toward the side of the engine 12, the outer diameters of the respective devices of the power train rotatably arranged around the second axis CL2 are gradually reduced.

[0021] The differential gear 44 is a well-known differential gear that receives input power and transmits equal driving torque to a pair of drive wheels 50 via a pair of axles 48 while allowing an appropriate difference in rotational speed.

[0022] The countershaft 26 is a rotating member rotatable about a third axis CL3. The third axis CL3 is parallel to the first axis CL1 and the second axis CL2. A counter driven gear 36 is provided on the countershaft 26 so as to be non-rotatable relative to the counter drive gear 22. The counter driven gear 36 meshes with the counter drive gear 22 and with an outer peripheral gear 38. In the power split mechanism 20, a first electric motor torque Tmg1 [N·m], which is a reaction torque of a negative torque generated by the first electric motor MG1, is input to the sun gear S0 in response to a positive engine torque Te [N·m] input to the carrier CA0. The first electric motor torque Tmg1 is the output torque of the first electric motor MG1. As a result, a positive engine direct torque Td [N·m] appears at the ring gear R0 of the power split mechanism 20 during forward rotation. In this way, part of the engine torque Te is transmitted as engine direct torque Td to the ring gear R1 of the first planetary gear set 42a via the outer peripheral gear 38. The engine torque Te corresponds to the "engine power" in this invention.

[0023] According to this embodiment, (a) the engine 12 and the first electric motor MG1 are arranged to be rotatable about the first axis line CL1, (b) the reduction mechanism 42 includes a first planetary gear set 42a and a second planetary gear set 42b, (c) the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged to be rotatable about the second axis line CL2 that is parallel to the first axis line CL1, and (d) the first electric motor MG1 is arranged to be rotatable about the second axis line CL2 in the direction of the second axis line CL2. The second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged in this order from the motor MG1 side to the engine 12 side, and (e) the second rotor shaft 40 is connected to the sun gear S1 of the first planetary gear set 42a, the ring gear R1 of the first planetary gear set 42a is connected to the sun gear S2 of the second planetary gear set 42b, and the carrier CA2 of the second planetary gear set 42b is connected to the differential gear 44. With the configuration of (e) above, the reduction ratio of the reduction mechanism 42 including the first planetary gear set 42a and the second planetary gear set 42b is increased while an increase in the outer diameter of the reduction mechanism 42 relative to the second axis line CL2 is suppressed. In this way, an increase in the outer diameter of the reduction mechanism 42 relative to the second axis CL2 is suppressed, and the arrangement (d) above facilitates reducing the outer diameter of the powertrain devices (particularly the reduction mechanism 42) that are arranged to protrude from the first electric motor MG1 side toward the engine 12 in the direction of the second axis CL2 and are arranged to be rotatable about the second axis CL2. This allows the engine 12, which is arranged to be rotatable about the first axis CL1, and the powertrain devices, which are arranged to be rotatable about the second axis CL2 parallel to the first axis CL1, to be arranged while suppressing an increase in the inter-axis distance between the first axis CL1 and the second axis CL2. In other words, an increase in the overall size of the engine 12 and the powertrain devices is suppressed. For example, by suppressing an increase in the overall size of the engine 12 and the powertrain devices in the vertical direction, deterioration of the aerodynamic characteristics of the vehicle 10 is suppressed, and the degree of freedom in selecting an exterior design for the vehicle 10 is improved.

[0024] According to this embodiment, the first planetary gear set 42a is coupled to the ring gear R1 so that the engine torque Te is transmitted to the ring gear R1 as engine direct torque Td. In this way, the ring gear R1 of the first planetary gear set 42a is configured to combine the engine direct torque Td and the second electric motor torque Tmg2 [N·m]. This makes it possible to control the engine 12 to an efficient operating state and to transmit the required drive torque to the pair of drive wheels 50, for example. The second electric motor torque Tmg2 is the output torque of the second electric motor MG2 and corresponds to the "power of the second electric motor" in this invention.

[0025] According to this embodiment, (a) there is provided a power split mechanism 20 constituted by a single-pinion planetary gear set rotatably arranged about a first axis CL1, and (b) the engine 12 is coupled to the carrier CA0 of the power split mechanism 20, and the first electric motor MG1 is coupled to the sun gear S0 of the power split mechanism 20. As a result, the power split mechanism 20 is arranged to be rotatable about the same first axis CL1 as the engine 12, and the rotational speed of the engine 12 is increased and transmitted to the first electric motor MG1. In this way, when the engine 12 is coupled to the carrier CA0 of the power split mechanism 20 and the first electric motor MG1 is coupled to the sun gear S0 of the power split mechanism 20, the first electric motor MG1 is more likely to rotate at a higher speed than when not coupled. This improves the power generation efficiency of the first electric motor MG1. [Example]

[0026] FIG. 2 is a schematic diagram of a hybrid vehicle 110 (hereinafter simply referred to as "vehicle 110") according to a second embodiment of the present invention. In FIG. 2, arrows indicate the upper and lower sides of the vehicle 110 in the direction of a vertical line, and the left and right sides in the vehicle width direction. FIG. 2 is a view of the vehicle 110 as seen from the rear to the front. In FIG. 2, the devices shown inside the transaxle case 16 are shown reflecting their relative positional relationships in the up-down and left-right directions.

[0027] The vehicle 110 has substantially the same configuration as the vehicle 10 according to the first embodiment described above, but differs mainly in that the power of the engine 12 is not transmitted to the pair of drive wheels 50. Therefore, the following description will focus on the parts that are different from the first embodiment, and the same reference numerals will be used to denote substantially common parts, and the description will be omitted as appropriate.

[0028] The first electric motor MG1 in this embodiment is a rotating electric machine that has at least the function of a generator out of the function of an electric motor and the function of a generator, and is, for example, a so-called motor generator.

[0029] The vehicle 110 is provided with a speed-increasing planetary gear device 120 instead of the power split mechanism 20 of the vehicle 10 according to the first embodiment. Furthermore, the vehicle 110 does not have the counter shaft 26, the counter drive gear 22, the counter driven gear 36, and the outer peripheral gear 38 that are provided in the vehicle 10 according to the first embodiment.

[0030] The speed-increasing planetary gear set 120 is, for example, a single-pinion type planetary gear set. A first electric motor MG1 is connected to a sun gear S3 of the speed-increasing planetary gear set 120. A carrier CA3 of the speed-increasing planetary gear set 120 is connected to the engine 12 via the input shaft 32 and the damper 14. A non-rotating member (for example, the transaxle case 16) is connected to a ring gear R3 of the speed-increasing planetary gear set 120. In the speed-increasing planetary gear set 120, the rotation of the engine 12 is input to the carrier CA3, and the rotation speed is increased and output from the sun gear S3 to the first electric motor MG1. The first electric motor MG1 is rotationally driven by the power of the engine 12 input via the speed-increasing planetary gear set 120. The speed-increasing planetary gear set 120 corresponds to the "third planetary gear set" in this invention. The sun gear S3 corresponds to the "sun gear of the third planetary gear set" in this invention. The carrier CA3 corresponds to the "carrier of the third planetary gear set" of this invention.

[0031] According to this embodiment, similarly to the above-described first embodiment, (a) the engine 12 and the first electric motor MG1 are arranged to be rotatable about the first axis line CL1, (b) the reduction mechanism 42 includes a first planetary gear set 42a and a second planetary gear set 42b, (c) the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged to be rotatable about the second axis line CL2 that is parallel to the first axis line CL1, and (d) the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged to be rotatable about the second axis line CL2 that is parallel to the first axis line CL1. In this embodiment, the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged in this order from the first electric motor MG1 side toward the engine 12 side, and (e) the second rotor shaft 40 is connected to the sun gear S1 of the first planetary gear set 42a, the ring gear R1 of the first planetary gear set 42a is connected to the sun gear S2 of the second planetary gear set 42b, and the carrier CA2 of the second planetary gear set 42b is connected to the differential gear 44. This provides the same effects as those of the first embodiment based on this configuration.

[0032] According to this embodiment, (a) a speed-increasing planetary gear set 120 configured as a single-pinion planetary gear set rotatably arranged about a first axis line CL1 is provided, and (b) the engine 12 is coupled to the carrier CA3 of the speed-increasing planetary gear set 120, and the first electric motor MG1 is coupled to the sun gear S3 of the speed-increasing planetary gear set 120. As a result, the speed-increasing planetary gear set 120 is rotatably arranged about the same first axis line CL1 as the engine 12, and the rotational speed of the engine 12 is increased and transmitted to the first electric motor MG1. This makes it easier for the first electric motor MG1 to rotate at high speeds, improving the power generation efficiency of the first electric motor MG1. Preferably, for example, when the first electric motor MG1 is configured to have a small diameter and be capable of efficiently generating power at a high rotational speed, the power generation efficiency of the first electric motor MG1 is improved while the increase in the axial distance between the first axis line CL1 and the second axis line CL2 is more easily suppressed than when the first electric motor MG1 is not configured to have such a small diameter and be capable of efficiently generating power at a high rotational speed. [Example]

[0033] FIG. 3 is a schematic diagram of a hybrid vehicle 210 (hereinafter simply referred to as "vehicle 210") according to a third embodiment of the present invention. In FIG. 3, arrows indicate the upper and lower sides of the vehicle 210 in the direction of a vertical line, and the left and right sides in the vehicle width direction. FIG. 3 is a view of the vehicle 210 as seen from the rear to the front. In FIG. 3, the devices shown in transaxle case 16 are shown reflecting their relative positional relationships in the up-down and left-right directions.

[0034] The vehicle 210 has substantially the same configuration as the vehicle 110 according to the second embodiment, but differs mainly in that it does not include the speed-increasing planetary gear unit 120. Therefore, the following description will focus on the parts that are different from the second embodiment, and the same reference numerals will be used to denote substantially common parts, and the description thereof will be omitted as appropriate.

[0035] The vehicle 210 does not include the speed-increasing planetary gear unit 120 of the vehicle 110 according to the second embodiment, and the input shaft 32 is spline-fitted to the first rotor shaft 34 at a fitting portion F so as to be unable to rotate relative to the first rotor shaft 34. In this manner, the vehicle 210 is directly coupled to the engine 12 so that the engine 12 and the first electric motor MG1 rotate at the same speed. The first electric motor MG1 is driven to rotate by the power of the engine 12.

[0036] According to this embodiment, similarly to the above-described first and second embodiments, (a) the engine 12 and the first electric motor MG1 are arranged to be rotatable about the first axis line CL1, (b) the reduction mechanism 42 includes a first planetary gear set 42a and a second planetary gear set 42b, (c) the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged to be rotatable about the second axis line CL2 that is parallel to the first axis line CL1, and (d) the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged to be rotatable about the second axis line CL2 that is parallel to the first axis line CL1. In this direction, the second electric motor MG2, the first planetary gear set 42a, the second planetary gear set 42b, and the differential gear 44 are arranged in this order from the first electric motor MG1 side toward the engine 12 side, and (e) the second rotor shaft 40 is connected to the sun gear S1 of the first planetary gear set 42a, the ring gear R1 of the first planetary gear set 42a is connected to the sun gear S2 of the second planetary gear set 42b, and the carrier CA2 of the second planetary gear set 42b is connected to the differential gear 44. This provides the same effects as those of the first and second embodiments based on these configurations.

[0037] According to this embodiment, the engine 12 and the first electric motor MG1 are directly coupled so that they rotate at the same speed. When the engine 12 and the first electric motor MG1 are directly coupled, the dimensions of the engine 12 and the first electric motor MG1, which are arranged to be rotatable about the first axis line CL1, in the direction of the first axis line CL1 can be made smaller than when the engine 12 and the first electric motor MG1 are not directly coupled but are connected via, for example, the speed-increasing planetary gear unit 120. Preferably, for example, when the first electric motor MG1 has a large diameter and is configured to be able to generate electricity efficiently at a low rotational speed, the dimensions of the engine 12 and the first electric motor MG1 in the direction of the first axis line CL1 can be made smaller than when this is not the case.

[0038] The above-described embodiments of the present invention are merely illustrative, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[0039] In the above-described first, second, and third embodiments, the damper 14 is provided between the engine 12 and the first electric motor MG1, but the present invention is not limited to this. For example, the present invention can also be applied to an embodiment in which the damper 14 is not provided between the engine 12 and the first electric motor MG1.

[0040] In the first, second, and third embodiments described above, the second axis CL2 passes directly below the engine 12. However, the present invention is not limited to this. For example, the present invention can also be applied to an embodiment in which the second axis CL2 is offset either forward or rearward in the longitudinal direction of the vehicle 10, 110, or 210 with respect to the first axis CL1, and the second axis CL2 does not pass directly below the engine 12. Even in such an embodiment, the reduction gear ratio of the reduction mechanism 42, including the first planetary gear set 42a and the second planetary gear set 42b, is increased while an increase in the outer diameter relative to the second axis CL2 is suppressed. This allows the engine 12, which is rotatably disposed about the first axis CL1, and the devices of the powertrain, which are rotatably disposed about the second axis CL2, to be arranged while suppressing an increase in the inter-axis distance between the first axis CL1 and the second axis CL2. In other words, an increase in the overall size of the engine 12 and the devices of the powertrain is suppressed. [Explanation of symbols]

[0041] 10, 110, 210: hybrid vehicle, 12: engine, 20: power split mechanism (third planetary gear set), 40: second rotor shaft (output shaft of second electric motor), 42: reduction mechanism, 42a: first planetary gear set, 42b: second planetary gear set, 44: differential gear, 120: speed-increasing planetary gear set (third planetary gear set), CA0, CA3: carrier (carrier of third planetary gear set), CA2: carrier (carrier of second planetary gear set) , CL1: first axis, CL2: second axis, MG1: first electric motor, MG2: second electric motor, R1: ring gear (ring gear of first planetary gear set), S0, S3: sun gear (sun gear of third planetary gear set), S1: sun gear (sun gear of first planetary gear set), S2: sun gear (sun gear of second planetary gear set), Td: engine direct torque, Te: engine torque (engine power), Tmg2: second electric motor torque (second electric motor power)

Claims

1. A hybrid vehicle including an engine, a first electric motor rotated by the engine, a second electric motor, a reduction mechanism that reduces the power of the second electric motor, and a differential gear to which power is transmitted from the reduction mechanism, the engine and the first electric motor are each arranged to be rotatable about a first axis; the reduction mechanism includes a first planetary gear set and a second planetary gear set, the second electric motor, the first planetary gear set, the second planetary gear set, and the differential gear are each arranged to be rotatable about a second axis that is parallel to the first axis, the second electric motor, the first planetary gear set, the second planetary gear set, and the differential gear are arranged in this order from the first electric motor side to the engine side in the second axial direction, An output shaft of the second electric motor is connected to a sun gear of the first planetary gear set, a ring gear of the first planetary gear set is connected to a sun gear of the second planetary gear set, and a carrier of the second planetary gear set is connected to the differential gear. A hybrid vehicle characterized by:

2. The power of the engine is connected to the ring gear of the first planetary gear set so as to be transmitted as a direct torque from the engine.

2. The hybrid vehicle according to claim 1.

3. a third planetary gear device arranged rotatably about the first axis, The engine is connected to a carrier of the third planetary gear set, and the first electric motor is connected to a sun gear of the third planetary gear set.

3. The hybrid vehicle according to claim 1 or 2.

4. The engine and the first electric motor are directly connected to each other so that they rotate at the same speed.

2. The hybrid vehicle according to claim 1.

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