JP7813622B2 - power transmission device - Google Patents

Description

This disclosure relates to a power transmission device that includes a transmission that changes the speed of power transmitted from an engine to an input member and outputs it to an output shaft, and an electric motor that is connected to the output shaft via a reduction gear.

A known power transmission device includes a torque converter having a lock-up clutch and connected to an engine, a transmission connected to the torque converter, a clutch that connects the output shaft of the transmission to a drive shaft and disconnects the two, an electric motor disposed axially between the transmission and the clutch, and a reducer that amplifies torque from the electric motor and transmits it to the output shaft of the transmission (see, for example, Patent Document 1). The reducer of this power transmission device includes a sun gear connected to the rotor of the electric motor, a ring gear held by a housing, and a planetary carrier that supports multiple pinion gears that mesh with the sun gear and ring gear. The reducer is also disposed axially between the electric motor and the clutch, and the planetary carrier is connected to the rear end of the output shaft of the transmission. In this power transmission device, by engaging the lock-up clutch and the clutch and placing the transmission in a power transmitting state, torque from the electric motor (assist torque) can be output to the output shaft of the transmission in addition to torque from the engine.

U.S. Patent Application Publication No. 2007/0261901

In a vehicle including the above-described power transmission device, in order to output a higher assist torque from the electric motor to the output shaft of the transmission while preventing the electric motor from becoming larger, it is necessary to increase the reduction ratio of the reducer. However, Patent Document 1 does not disclose or suggest a specific structure for increasing the reduction ratio of the reducer.

The primary objective of this disclosure is to enable a power transmission device including a transmission, an electric motor, and a reducer that amplifies the torque from the electric motor and transmits it to the end of the transmission's output shaft, to output greater torque from the electric motor to the transmission's output shaft while minimizing increases in size and weight of the entire device.

The power transmission device disclosed herein includes a transmission that changes the speed of power transmitted from an engine to an input member and outputs it to an output shaft, a power transmission member connected to the end of the output shaft opposite the engine side, an electric motor arranged axially between the transmission and the power transmission member, a reducer that amplifies the torque from the electric motor and transmits it to the output shaft, and a case that houses the transmission, the electric motor, and the reducer, wherein the reducer is a planetary gear mechanism that includes an input element that rotates integrally with the rotor of the electric motor, a fixed element fixed to the case, and an output element connected to the end of the output shaft between the electric motor and the power transmission member in the axial direction, and the output element supports the input element from the radially inside and is rotatably supported by the case via a bearing arranged radially outside, and the end of the output shaft to which the output element and the power transmission member are connected has a constant outer diameter along the axial direction .

In the power transmission device disclosed herein, torque from the electric motor is amplified by a reducer and transmitted to the end of the transmission's output shaft opposite the engine side, where it can be output together with the torque from the engine to a power transmission member connected to that end. The reducer is a planetary gear mechanism including an input element that rotates integrally with the electric motor's rotor, a fixed element fixed to the case, and an output element. The output element of the reducer is connected to the end of the output shaft opposite the engine side, axially between the electric motor and the power transmission member. The output element supports the input element from the radially inner side and is rotatably supported by the case via a bearing disposed radially outward. As a result, the end of the output shaft opposite the engine side is rotatably (radially) supported by the case via the output element. Therefore, in the power transmission device disclosed herein, it is not necessary to expand the diameter of the end of the output shaft to restrict axial movement of the output shaft by the case via the bearing, as is the case when the end of the output shaft opposite the engine side is supported by the case via a bearing. Therefore, the outer diameter of the end can be made constant. This makes it possible to reduce the inner diameter of the output element and the outer diameter of the portion of the output element that supports the input element, thereby reducing the diameter of the input element and the reference circle diameter of the input element.As a result, the power transmission device disclosed herein can increase the reduction ratio of the reducer, thereby suppressing increases in the size of the electric motor, and therefore the size and weight of the entire device, while outputting a greater torque to the transmission output shaft than the electric motor.

1 is a schematic configuration diagram showing a vehicle equipped with a power transmission device according to the present disclosure. 1 is an enlarged view of a main portion of a power transmission device according to the present disclosure; FIG. 10 is a schematic diagram showing a vehicle equipped with another power transmission device of the present disclosure.

Next, we will explain the form for implementing the invention of this disclosure with reference to the drawings.

FIG. 1 is a schematic diagram showing a vehicle V equipped with a power transmission device 1 according to the present disclosure. The vehicle V shown in the figure is a rear-wheel-drive, four-wheel-drive vehicle that includes an engine (internal combustion engine) EG in addition to the power transmission device 1. In this embodiment, the engine EG is a multi-cylinder gasoline engine (e.g., a V6 engine) that converts the reciprocating motion of pistons resulting from the combustion of a mixture of gasoline (hydrocarbon-based fuel) and air in multiple combustion chambers (cylinders) into rotational motion of a crankshaft. The engine EG includes an electronically controlled throttle valve, multiple intake and exhaust valves, a variable valve mechanism, multiple fuel injection valves, multiple spark plugs, an exhaust purification system, and other components (all not shown). Furthermore, a motor-generator (not shown) is connected to the crankshaft of the engine EG to generate electricity using power from the engine EG and to crank the engine EG. However, the engine EG may also be an LPG engine or a diesel engine.

As shown in FIG. 1, the power transmission device 1 includes a starting device 2, a mechanical oil pump 3, an electric oil pump (not shown), a hydraulic control device 4, a transmission 5, a transfer 6, a motor-generator MG, a reduction gear 7, and a case 8 housing these elements. The starting device 2 includes a torque converter 21, a lock-up clutch 22, and a damper mechanism 23. The torque converter 21 includes a pump impeller connected to the crankshaft of the engine EG via a drive plate and a front cover, a turbine runner connected to the input member (input shaft) 5i of the transmission 5, and a stator that rectifies the flow of hydraulic oil from the turbine runner to the pump impeller to amplify torque. The lock-up clutch 22 is a multi-plate or single-plate friction hydraulic clutch that connects and disconnects the front cover and the input member 5i of the transmission 5. The damper mechanism 23 has multiple rotating elements and elastic bodies, and damps vibrations between the front cover and the input member 5i of the transmission 5. However, the starting device 2 may also include a fluid coupling without a stator instead of the torque converter 21.

The mechanical oil pump 3 is a gear pump including an inner rotor (internal gear) connected to the pump impeller of the torque converter 21 and an outer rotor (external gear), and is driven by power from the engine EG. The mechanical oil pump 3 and the electric oil pump each draw and discharge hydraulic oil (ATF) from an oil pan formed at the bottom of the case 8. The hydraulic control device 4 includes a valve body with multiple oil passages, multiple regulator valves, multiple linear solenoid valves, etc. The hydraulic control device 4 regulates the pressure of the hydraulic oil (hydraulic pressure) from at least one of the mechanical oil pump 3 and the electric oil pump, and supplies it to the torque converter 21, lock-up clutch 22, hydraulic engagement elements of the transmission 5, and various lubrication targets, etc.

The transmission 5 is a multi-speed transmission, for example, with 6-10 speeds, that includes an input member 5i, an output member 5o, multiple planetary gear mechanisms, and multiple clutches and brakes (hydraulic engagement elements). The transmission 5 shifts the power (torque) transmitted from the engine EG to the input member 5i via either a torque converter 21 or a lock-up clutch 22 into multiple speeds and outputs it to the output member 5o. As shown in FIG. 1, the front end 51 of the output shaft 50, which extends toward the rear of the vehicle V and is the end on the engine EG side, is connected (fixed) to the output member 5o of the transmission 5 via a spline.

The transfer case 6 includes an input shaft (power transmission member) 6i, a front propeller shaft 6f (first shaft), a rear propeller shaft 6r (second shaft), an auxiliary transmission, a power distribution mechanism, a center differential mechanism, a differential lock mechanism, and other components (all not shown). As shown in FIG. 1, the input shaft 6i of the transfer case 6 is spline-connected (fixed) to the rear end 52 of the output shaft 50 of the transmission 5, which is the end opposite the engine EG. The transfer case 6 distributes and transmits the power (torque) transmitted to the input shaft 6i to the front propeller shaft 6f (first shaft) and the rear propeller shaft 6r (second shaft). The power output by the transfer case 6 to the front propeller shaft 6f is transmitted to the left and right front wheels Wf via the front differential gear 9f. The power output to the rear propeller shaft 6r by the transfer 6 is transmitted to the left and right rear wheels Wr via the rear differential gear 9r.

The motor generator MG is a synchronous generator motor (three-phase AC motor) including a rotor R with an embedded permanent magnet and a stator S wound with three-phase coils. It is positioned axially between the transmission 5 and the transfer 6. The rotor R of the motor generator MG is fixed to a hollow motor shaft MS, through which the output shaft 50 of the transmission 5 is inserted. The motor generator MG is connected to the rear end 52 of the output shaft 50 via a reduction gear 7. The motor generator MG exchanges power with a battery (high-voltage battery) (not shown) via a power control unit (PCU) including an inverter, a boost converter, and other components (not shown). It operates as an electric motor driven by power from the battery to generate drive torque. The motor generator MG also operates as a generator that generates power using at least a portion of the power from the engine EG when it is operating under load, and outputs regenerative braking torque when braking the vehicle V.

The reducer 7 is a single-pinion planetary gear mechanism (differential rotation mechanism) including a sun gear (input element) 71, a ring gear (fixed element) 72, and a planetary carrier (output element) 74 that rotatably supports multiple pinion gears 73. It is disposed axially between the motor generator MG and the transfer 6. The sun gear 71 of the reducer 7 is connected to the motor shaft MS so as to rotate integrally with the rotor R of the motor generator MG. The ring gear 72 is non-rotatably fixed to the case 8, which serves as a stationary member. The planetary carrier 74, together with the input shaft 6i of the transfer 6, is connected (fixed) to the rear end 52 of the output shaft 50 of the transmission 5 via a spline.

The case 8 of the power transmission device 1 includes a transmission case 80, a motor case 81, a gear case 82, and a transfer case 83. In this embodiment, the transmission case 80, the motor case 81, the gear case 82, and the transfer case 83 are all cast products made of, for example, aluminum alloy or steel. The transmission case 80 houses the starting device 2, the mechanical oil pump 3, the transmission 5, etc., and is fastened (coupled) to the engine block of the engine EG via multiple bolts. The motor case 81 houses the motor generator MG, etc., and is fastened (coupled) to the rear end of the transmission case 80 via multiple bolts. The gear case 82 houses the reducer 7, etc., and is fastened (coupled) to the rear end of the motor case 81 via multiple bolts. The transfer case 83 houses the transfer 6, etc., and is fastened (coupled) to the rear end of the gear case 82 via multiple bolts.

With the power transmission device 1 configured as described above, the operation of the engine EG is stopped, the lock-up clutch 22 is disengaged, and the transmission 5 is in neutral. By driving the motor generator MG with power from the battery, torque (only) from the motor generator MG can be transmitted to the output shaft 50, allowing the vehicle V to start and travel. Furthermore, with the transmission 5 in a power transmission state, the motor generator MG can be driven with power from the battery to output cranking torque while the lock-up clutch 22 is slip-engaged, thereby cranking and starting the engine EG.

After engine EG has started, the engine EG can be operated, for example, at an operating point near the optimal fuel economy line, while the battery is charged with power generated by the motor generator MG according to the battery's SOC. The torque (assist torque) from the motor generator MG, which is driven by power from the battery, can be amplified by the reducer 7 and added to the torque from the engine EG for output to the output shaft 50. Therefore, power transmission device 1 can ensure good power performance of the vehicle V while improving the fuel economy of the engine EG.

Figure 2 is an enlarged view of the main parts of the power transmission device 1, showing the structure around the motor generator MG and the reducer 7.

As shown in FIG. 2, the motor case 81 has an annular support portion 81s extending radially inward from its inner circumferential surface. The stator S of the motor generator MG is non-rotatably fastened (fixed) to the base (thick portion) on the outer circumferential side of the support portion 81s via multiple bolts (not shown). The front end (left end in FIG. 2) of the motor shaft MS, which is fixed to the rotor R and faces the engine EG, is rotatably (radially) supported by the inner circumferential portion of the support portion 81s via a bearing (ball bearing) Bmf. The rear end (right end in FIG. 2) of the motor shaft MS, which faces away from the engine EG, is rotatably (radially) supported by a cover 82c of the gear case 82 via a bearing (ball bearing) Bmr. The cover 82c is fastened (fixed) to the gear case 82 via multiple bolts to close the opening of the motor case 81 on the side opposite the engine EG.

The opening of the motor case 81 on the engine EG side is closed by a cover 81c, which is fastened (fixed) to the front end of the motor case 81 via multiple bolts. A space is defined axially between the cover 81c and the support portion 81s, and a resolver Rsv is located in this space to detect the rotational position of the motor shaft MS, i.e., the rotor R. Furthermore, a lubrication/cooling pipe Plc with multiple oil holes is installed between the support portion 81s of the motor case 81 and the cover 82c, positioned radially outward and above the stator S. Hydraulic oil is supplied to the lubrication/cooling pipe Plc from the hydraulic control device 4 via oil passages formed in the motor case 81, oil passages formed in the cover 81c, and oil passages formed in the output shaft 50 and output member 5o. This allows hydraulic oil to be supplied as a lubricating and cooling medium to the stator S and rotor R of the motor-generator MG from the multiple oil holes in the lubrication/cooling pipe Plc.

As shown in FIG. 2, the sun gear 71 of the reducer 7 includes a small-diameter portion fixed via splines to the rear end of the motor shaft MS on the side opposite the engine EG, and a large-diameter portion on which multiple external teeth are formed. Furthermore, in this embodiment, the ring gear 72 of the reducer 7 is fitted to splines formed on the inner circumferential surface of the gear case 82 and is non-rotatably fixed to the gear case 82, i.e., the case 8, via a snap ring. The planetary carrier 74 of the reducer 7 includes a carrier body 740 and a carrier cover 741 that are fixed integrally to each other and support a pinion shaft inserted through multiple pinion gears 73, and a carrier hub 742 that is fixed to the inner circumferential portion of the carrier body 740 so as to be positioned radially inward of the carrier body 740.

The carrier hub 742 of the planetary carrier 74 includes a cylindrical portion 743 and an annular flange portion 744 extending radially outward from the outer peripheral surface of the axially central portion of the cylindrical portion 743. As shown in the figure, the outer peripheral portion of the flange portion 744 of the carrier hub 742 is fixed to the inner peripheral portion of the carrier body 740 by welding. Furthermore, splines are formed on the inner peripheral surface of the cylindrical portion 743, and the splines of the cylindrical portion 743 mate with splines SP formed on the rear end portion 52 into which the input shaft 6i of the transfer 6 is fitted. As shown in FIG. 2, the cylindrical portion 743 of the planetary carrier 74 (carrier hub 742) is fitted with the splines SP on the rear end portion 52 of the output shaft 50. Furthermore, the rear end 52 of the output shaft 50 protrudes from the cylindrical portion 743 toward the rear of the vehicle V (to the right in Figure 2), and the input shaft 6i of the transfer 6 is fitted into the splines SP of the rear end 52 protruding from the cylindrical portion 743. This connects the planetary carrier 74 and the input shaft 6i of the transfer 6 to the rear end 52 so that they rotate integrally with the output shaft 50.

The outer peripheral surface of the front end of the cylindrical portion 743 on the engine EG side (left side in Figure 2) is formed into a cylindrical shape, and this front end of the cylindrical portion 743 rotatably supports the inner peripheral surface of the sun gear 71 (large diameter portion) from the radially inner side via a bushing Bs. Furthermore, a thrust bearing Bt is disposed axially between the end face (right end face in Figure 2) of the sun gear 71 (large diameter portion) and the flange portion 744 of the carrier hub 742. The rear end of the cylindrical portion 743 on the opposite side from the engine EG side (right side in Figure 2) is rotatably supported (radially) by an annular support portion 82s extending radially inward from the inner peripheral surface of the gear case 82, via a bearing (ball bearing) Bsr disposed radially outward.

As a result, the rear end 52 of the output shaft 50, on the side opposite the engine EG, is rotatably (radially) supported by the gear case 82, i.e., the case 8, via the cylindrical portion 743 of the planetary carrier 74. In addition, in this embodiment, the front end 51 of the output shaft 50 on the engine EG side is rotatably (radially) supported by the cover 81c, i.e., the case 8, fixed to the motor case 81, via a bearing (ball bearing) Bsf arranged radially outward. Furthermore, a snap ring SR is attached to the output shaft 50 on the engine EG side (left side in Figure 2) so as to abut against the inner race Li of the bearing Bsf.

As described above, in the power transmission device 1, torque (assist torque) from the motor-generator MG is amplified by the reduction gear 7 and transmitted to the rear end 52 of the output shaft 50 of the transmission 5, opposite the engine EG side, and output together with the torque from the engine EG to the input shaft 6i (power transmission member) of the transfer case 6, which is connected to the rear end 52. In addition, in the power transmission device 1, the planetary carrier 74, which is the output element of the reduction gear 7, is connected to the rear end 52 of the output shaft 50 axially between the motor-generator MG and the input shaft 6i of the transfer case 6. Furthermore, the cylindrical portion 743 of the planetary carrier 74 rotatably supports the sun gear 71, which is the input element of the reduction gear 7, from the radially inner side and is rotatably supported by the case 8 (gear case 82) via the bearing Bsr located radially outward. The rear end 52 of the output shaft 50 is rotatably supported by the case 8 (gear case 82) via the planetary carrier 74 (cylindrical portion 743).

Therefore, in the power transmission device 1, unlike when the rear end 52 of the output shaft 50 is supported by the case 8 via a bearing, there is no need to expand the diameter of the rear end 52 to restrict axial movement of the output shaft 50 via the case 8. This eliminates the need to maintain a constant outer diameter of the rear end 52 (the outer diameter of the crests of the splines SP). This allows the inner diameter of the cylindrical portion 743 of the planetary carrier 74 and the outer diameter of the portion of the cylindrical portion 743 that supports the sun gear 71 to be reduced, thereby reducing the diameter of the sun gear 71 (the large-diameter portion having external teeth) and the reference circle diameter of the sun gear 71. As a result, in the power transmission device 1, the reduction ratio of the reducer 7 (reference circle diameter of the ring gear 72 / reference circle diameter of the sun gear 71) can be increased. This allows for a larger assist torque to be output from the motor generator MG to the output shaft 50 of the transmission 5 while minimizing the increase in size of the motor generator MG, i.e., the overall size and weight of the device.

In addition, in the power transmission device 1, the rear end 52 of the output shaft 50 of the transmission 5 is formed with a spline SP into which the cylindrical portion 743 of the planetary carrier 74 and the input shaft 6i of the transfer 6 are fitted. In this way, by sharing the spline SP of the rear end 52 into which the planetary carrier 74 and the input shaft 6i are fitted, it is possible to reduce the processing cost of the output shaft 50 and improve the ease of assembly of the planetary carrier 74 and the input shaft 6i to the output shaft 50.

Furthermore, the front end 51 of the output shaft 50 on the engine EG side is rotatably supported by the case 8 (cover 81c) via a bearing (second bearing) Bsf located radially outward, and a snap ring SR is attached to the output shaft 50 so that it abuts against the inner race Li of the bearing Bsf on the engine EG side. This makes it possible for movement of the output shaft 50 in the direction from the engine EG side toward the input shaft 6i side to be restricted by the case 8 via the snap ring SR and bearing Bsf.

In addition, in the power transmission device 1, the reducer 7 is a single-pinion planetary gear mechanism that includes a sun gear 71 as an input element, a ring gear 72 as a fixed element, and a planetary carrier 74 as an output element that supports multiple pinion gears 73 that mesh with the sun gear 71 and ring gear 72. This makes it possible to increase the reduction ratio of the reducer 7 while preventing an increase in the number of parts and an increase in the size and weight of the entire device.

However, the reducer 7 may also be a double-pinion planetary gear mechanism that includes a sun gear as the input element, a ring gear as the output element, and a planetary carrier as a fixed element that holds multiple pairs of pinion gears that mesh with each other and can rotate and revolve freely, with one pinion gear meshing with the sun gear and the other with the ring gear. In this case, the hub of the ring gear, which serves as the output element, is fitted into the splines on the rear end 52 of the output shaft 50, and the sun gear is supported radially by the hub.

Furthermore, the vehicle V on which the above-described power transmission device 1 is mounted is a four-wheel drive vehicle, and the rear end 52 of the output shaft 50 of the transmission 5 is connected to the input shaft 6i of the transfer case 6 as well as the planetary carrier 74 of the reduction gear 7. However, the power transmission member connected to the rear end 52 of the output shaft 50 is not limited to the input shaft 6i. That is, as shown in FIG. 3, if the vehicle V is a rear-wheel drive vehicle and is equipped with a power transmission device 1B in which the transfer case 6 is omitted from the above-described power transmission device 1, a propeller shaft PS may be connected to the rear end 52 of the output shaft 50 as a power transmission member, and the output shaft 50 and the differential gear 9 may be connected via the propeller shaft PS.

As explained above, the power transmission device of the present disclosure includes a transmission (5) that changes the speed of power transmitted from an engine (EG) to an input member (5i) and outputs the power to an output shaft (50), a power transmission member (6i, PS) connected to the end (52) of the output shaft (50) opposite the engine (EG) side, an electric motor (MG) disposed axially between the transmission (5) and the power transmission member (6i, PS), a reducer (7) that amplifies the torque from the electric motor (MG) and transmits it to the output shaft (50), and a case (8) that houses the transmission (5), the electric motor (MG), and the reducer (7), The planetary gear mechanism includes an input element (71) that rotates integrally with the rotor (R) of the motor (MG), a fixed element (72) fixed to the case (8, 82), and an output element (74) that is connected to the end (52) of the output shaft (50) between the electric motor (MG) and the power transmission member (6i, PS) in the axial direction, where the output element (74) supports the input element (71) from the radially inner side and is rotatably supported by the case (8) via a bearing (Bsr) arranged radially outward, and the end (52) of the output shaft (50) to which the output element (74) and the power transmission member (6i, PS) are connected has a constant outer diameter.

In the power transmission device disclosed herein, torque from the electric motor is amplified by a reducer and transmitted to the end of the transmission's output shaft opposite the engine side, where it can be output together with the torque from the engine to a power transmission member connected to that end. The reducer is a planetary gear mechanism including an input element that rotates integrally with the electric motor's rotor, a fixed element fixed to the case, and an output element. The output element of the reducer is connected to the end of the output shaft opposite the engine side, axially between the electric motor and the power transmission member. The output element supports the input element from the radially inner side and is rotatably supported by the case via a bearing disposed radially outward. As a result, the end of the output shaft opposite the engine side is rotatably (radially) supported by the case via the output element. Therefore, in the power transmission device disclosed herein, it is not necessary to expand the diameter of the end of the output shaft to restrict axial movement of the output shaft by the case via the bearing, as is the case when the end of the output shaft opposite the engine side is supported by the case via a bearing. Therefore, the outer diameter of the end can be made constant. This makes it possible to reduce the inner diameter of the output element and the outer diameter of the portion of the output element that supports the input element, thereby reducing the diameter of the input element and the reference circle diameter of the input element.As a result, the power transmission device disclosed herein can increase the reduction ratio of the reducer, thereby suppressing increases in the size of the electric motor, and therefore the size and weight of the entire device, while outputting a greater torque to the transmission output shaft than the electric motor.

The reducer (7) may also be a single-pinion planetary gear mechanism including a sun gear (71) as the input element, a ring gear (72) as the fixed element, and a planetary carrier (74) as the output element that supports multiple pinion gears (73) meshing with the sun gear (71) and the ring gear (72).

In a power transmission device including such a reducer, it is possible to increase the reduction ratio of the reducer while suppressing an increase in the number of parts and an increase in the size and weight of the entire device.

Furthermore, the end (52) of the output shaft (50) may be formed with a spline (SP) into which the output element (74) and the power transmission member (6i, PS) are fitted.

In this way, by sharing the same splines at the end where the output element and power transmission member are fitted, it is possible to reduce the processing costs of the output shaft and improve the ease of assembly of the output element and power transmission member to the output shaft.

Furthermore, the output shaft (50) may be rotatably supported by the case (8, 81c) via a second bearing (Bsf) arranged radially outward on the engine (EG) side, and a snap ring (SR) may be attached to the output shaft (50) so as to abut against the inner race (Li) of the second bearing (Bsf) on the engine (EG) side.

This allows the case to restrict movement of the output shaft in the direction from the engine side toward the power transmission member side via the snap ring and second bearing.

Furthermore, the power transmission member may be the input shaft (6i) of the transfer (6), or a propeller shaft (PS) connecting the output shaft (50) of the transmission (5) and the differential gear (9).

The invention of this disclosure is in no way limited to the above-described embodiment, and it goes without saying that various modifications can be made within the scope of this disclosure. Furthermore, the above-described embodiment is merely one specific form of the invention described in the Summary of the Invention section, and does not limit the elements of the invention described in the Summary of the Invention section.

The disclosed invention can be used in industries such as power transmission and vehicle manufacturing.

1, 1B power transmission device, 2 starting device, 5 transmission, 5i input member, 5o output member, 50 output shaft, 51 front end, 52 rear end, 6 transfer, 6f front propeller shaft, 6i input shaft, 6r rear propeller shaft, 7 reducer, 71 sun gear, 72 ring gear, 73 pinion gear, 74 planetary carrier, 740 carrier body, 741 carrier cover, 742 carrier hub, 743 cylindrical portion, 744 flange portion, 8 case, 81 motor case, 81c cover, 81s support portion, 82 gear case, 82c cover, 82s support portion, 9 differential gear, 9f front differential gear, 9r rear differential gear, MG motor generator, R rotor, S stator, SP Spline, V vehicle.

Claims (5)

A power transmission device including a transmission that changes the speed of power transmitted from an engine to an input member and outputs the power to an output shaft, a power transmission member that is connected to an end of the output shaft opposite to the engine side, an electric motor that is arranged axially between the transmission and the power transmission member, a reducer that amplifies torque from the electric motor and transmits it to the output shaft, and a case that houses the transmission, the electric motor, and the reducer,
the reducer is a planetary gear mechanism including an input element that rotates integrally with the rotor of the electric motor, a fixed element that is fixed to the case, and an output element that is connected to the end of the output shaft between the electric motor and the power transmission member in the axial direction,
the output element supports the input element from the radially inner side, and is rotatably supported by the case via a bearing arranged radially outward,
A power transmission device in which the end of the output shaft to which the output element and the power transmission member are connected has a constant outer diameter along the axial direction . 2. The power transmission device according to claim 1,
The reducer is a power transmission device that is a single-pinion planetary gear mechanism that includes a sun gear as the input element, a ring gear as the fixed element, and a planetary carrier as the output element that supports a plurality of pinion gears that mesh with the sun gear and the ring gear. 3. The power transmission device according to claim 1,
A power transmission device in which the end of the output shaft is formed with a spline into which the output element and the power transmission member are fitted. The power transmission device according to any one of claims 1 to 3,
the output shaft is rotatably supported by the case via a second bearing disposed radially outward on the engine side,
a snap ring attached to the output shaft so as to abut against an inner race of the second bearing on the engine side; The power transmission device according to any one of claims 1 to 4,
A power transmission device in which the power transmission member is an input shaft of a transfer case or a propeller shaft that connects the output shaft of the transmission and a differential gear.