POWER TRANSMISSION DEVICE FOR A VEHICLE

Abstract

A power transmission device for a vehicle, comprising: an auxiliary electric drive unit (2) which is operated as an electric motor or a generator; a torque conversion device comprising a planetary gear (PG) having a first, a second and a third rotation element (N1, N2, N3), wherein the first rotation element (N1) is connected to the electric auxiliary drive unit (2), the second rotation element (N2) is connected to an internal combustion engine (ENG), and the third rotation element (N3) is operated as an output element; an input device comprising: a first input shaft (8) which is selectively connected to the second rotational element (N2) by means of a clutch (CL1) and is provided with at least one input gear (G1, G2, G3) fixedly arranged thereon; and a second input shaft (10) which is arranged coaxially to the first input shaft (8) without rotationally impairing the first input shaft (8), is directly connected to the third rotational element (N3), is selectively connected to the second rotational element (N2) by means of a second clutch (CL2) and is provided with at least one input gear (G4, G5, G6, G7) fixedly arranged thereon; and a gear output device (OUT1, OUT2) which converts a torque of the input device and outputs the converted torque, wherein the gear output device (OUT1, OUT2) comprises a first and a second output shaft (12, 14) which are parallel to the first and to the second input shaft (8, 10), and a plurality of gear wheels (D1, D2, D3, D4, D5, D6, D7, RG), which are connected by means of Synchronization modules (SL1, SL2, SL3, SL4) arranged on the first and second output shafts (12, 14), operatively connected to the first output shaft (12) or the second output shaft (14), and wherein the first input shaft (8) is a hollow shaft and the second input shaft (10) penetrates the first input shaft (8) coaxially.

Description

[0001] The present invention relates to a power transmission device for a vehicle which can achieve smooth starting and shifting and can improve fuel economy and acceleration performance as a consequence of adding an auxiliary electric drive unit and a torque conversion device to a dual-clutch power transmission device.

[0002] Environmentally friendly vehicle technology is very important, as the survival of the future automotive industry depends on it. Vehicle manufacturers are focusing on developing environmentally friendly vehicles to meet environmental and fuel consumption regulations.

[0003] Some examples of future vehicles include an electric vehicle (EV) and a hybrid electric vehicle (HEV), which use electric power, and a dual-clutch transmission (DCT), which improves efficiency and convenience.

[0004] Additionally, vehicle manufacturers are promoting the improvement of efficiency in the power delivery system to meet country-specific emissions regulations and improve fuel consumption. To improve the efficiency of the power delivery system, vehicle manufacturers are attempting to implement an "idle stop and go" (ISG) system and a regenerative braking system (or energy recovery braking system) into practical use.

[0005] The ISG system stops the internal combustion engine when a vehicle stops and restarts the engine when the vehicle starts moving. The regenerative braking system uses a generator during braking, which uses the vehicle's kinetic energy instead of braking through friction. It stores the electrical energy generated during braking in a battery (or accumulator), and reuses the electrical energy when the vehicle is moving.

[0006] Furthermore, a hybrid electric vehicle is a vehicle that utilizes two or more power sources, and these two or more power sources can be combined in various ways. Typically, a hybrid electric vehicle uses a gasoline engine or a diesel engine powered by fossil fuel, and an electric motor-generator (or an electrical device that operates as a motor or generator depending on the operating mode) powered by electrical energy.

[0007] Additionally, an example of a transmission applied to a hybrid electric vehicle is the DCT. With the DCT, two clutches are applied to a manual transmission layout (e.g., a manual transmission). Therefore, efficiency and convenience can be improved.

[0008] This means that the DCT alternately engages odd and even gears using two clutches. A mechanism for alternately engaging odd and even gears improves shift feel, solving the problems of a conventional manual transmission (MT) and an automated manual transmission (AMT).

[0009] However, the DCT has the problems of clutch damage and energy loss due to possible clutch slippage during starting, a possible non-guarantee of safety, since rolling backward due to clutch slippage occurs excessively when starting on an incline, and a possible strong shift shock (or jolt) compared to an automatic transmission, since a shift time is kept short due to the thermal capacity of a clutch.

[0010] From the subsequently published US 8 784 245 B2, a power transmission device for a vehicle is known, comprising: an electric auxiliary drive unit operated as an electric motor or a generator; a torque conversion device comprising a planetary gear having a first, a second and a third rotational element, wherein the first rotational element is connected to the electric auxiliary drive unit, the second rotational element is connected to an internal combustion engine and the third rotational element is operated as an output element; an input device comprising: a first input shaft selectively connected to the second rotational element by means of a clutch and provided with at least one input gear fixedly arranged thereon;and a second input shaft arranged coaxially with the first input shaft without rotationally interfering with the first input shaft, directly connected to the third rotation element, selectively connected to the second rotation element by means of a second clutch, and provided with at least one input gear fixedly arranged thereon;and a gear output device that converts torque from the input device and outputs the converted torque. The gear output device includes first and second output shafts arranged parallel to the first and second input shafts, and a plurality of gears that are operatively connected to the first output shaft or the second output shaft selectively by means of synchronization modules arranged on the first and second output shafts. Another power transmission device for a vehicle is known from the subsequently published DE 10 2010 063 582 A1.

[0011] The object of the present invention is to provide a power transmission device (e.g., a manual transmission with a front-mounted planetary gear) for a vehicle, which has advantages in realizing smooth starting and shifting by adding an auxiliary electric drive unit and a torque conversion device to a dual-clutch power transmission device, improving fuel economy by enabling regenerative braking, and improving acceleration performance by utilizing torque of an electric motor-generator during acceleration.

[0012] This object is achieved by a power transmission device for a vehicle according to claim 1. Further developments are the subject of the dependent claims.

[0013] The power transmission device for a vehicle according to the invention comprises: an electric auxiliary drive unit operated as an electric motor or a generator; a torque conversion device comprising a planetary gear train (or a planetary set or a planetary gear train) having a first, a second and a third rotational element, wherein the first rotational element is connected to the electric auxiliary drive unit, the second rotational element is connected to an internal combustion engine and the third rotational element is operated as an output element; an input device comprising: a first input shaft (or drive shaft or input shaft) selectively connected to the second rotational element by means of a first clutch and connected to at least one input gear (or drive gear orinput gear), which is fixedly arranged thereon; and a second input shaft, which is arranged coaxially to the first input shaft without rotationally affecting (or influencing) the first input shaft, is directly connected to the third rotation element, is selectively connected to the second rotation element by means of a second clutch, and is provided with at least one input gear, which is fixedly arranged thereon; and a gear output device, which converts a torque of the input device and outputs the converted torque, wherein the gear output device has a first and a second output shaft (or output shaft), which are arranged parallel to the first and second input shafts, and a plurality of gear gears (or output gears), which are connected by means of synchronization modules (e.g.comprising synchronizer ring and synchronizer body) arranged on the first and second output shafts, operatively connected to the first output shaft or the second output shaft selectively.

[0014] In the power transmission device for a vehicle according to the invention, the first input shaft is a hollow shaft and the second input shaft penetrates the first input shaft coaxially.

[0015] The electric auxiliary drive unit may include: a rotor connected to the first rotating element of the torque conversion device; and a stator enclosing the rotor and secured to a transmission housing.

[0016] The planetary gear may be a planetary gear with double planetary gears (e.g., directly meshing planetary gears in pairs), the first rotation element may be a sun gear, the second rotation element may be a planetary gear carrier; and the third rotation element may be a ring gear.

[0017] The at least one input gear fixedly arranged on the first input shaft may comprise a first input gear operated at a first forward gear, a second input gear operated at a seventh forward gear, and a third input gear operated at a fifth forward gear, wherein the first, second, and third input gears are arranged in the stated order from a front side to a rear side of the first input shaft.

[0018] In further developments, the at least one input gear, which is fixedly arranged on the second input shaft, can have a fourth input gear, which is operated at a fourth forward gear, a fifth input gear, which is operated at a second forward gear, a sixth input gear, which is operated at a reverse gear, and a seventh input gear, which is operated at a sixth forward gear, wherein the fourth, the fifth, the sixth and the seventh input gear are arranged in the named order from a front side to a rear side of the second input shaft.

[0019] In further developments, the gear output device can comprise: a first gear output unit which has a first output shaft which is arranged parallel to the first and the second input shaft, and a first and a second synchronization module which are arranged on the first output shaft, wherein the first gear output unit selectively connects four gear gears to the first output shaft by means of a selective operation of the first and the second synchronization module and the torque as four gears (or a gear ratio ora torque changed according to the gear ratio); a second gear output unit having a second output shaft arranged in parallel with the first and second input shafts, and third and fourth synchronization modules arranged on the second output shaft, the second gear output unit selectively connecting other four gears to the second output shaft by means of selective operation of the third and fourth synchronization modules and outputting the torque as other four gears; and a reverse gear output unit having a reverse gear shaft and an idle gear arranged on the reverse gear shaft and meshing with any one input gear among the input gears on the second input shaft and any one speed gear among the speed gears on the second output shaft.

[0020] In further developments, the first synchronization module can selectively connect the first gear, which is engaged with the first input gear, or the third gear, which is engaged with the third input gear, to the first output shaft.

[0021] In further developments, the second synchronization module can selectively connect the second gear, which is engaged with the fifth input gear, or the sixth gear, which is engaged with the seventh input gear, to the first output shaft.

[0022] In further developments, the third synchronization module can selectively connect the seventh gear, which is engaged with the second input gear, or the fifth gear, which is engaged with the third input gear, to the second output shaft.

[0023] In further developments, the fourth synchronization module can selectively connect the fourth gear gear meshing with the fourth input gear or a reverse gear meshing with the idle gear to the second output shaft.

[0024] In further developments, the idle gear can be in engagement with the sixth input gear of the second input shaft.

[0025] In further developments, the at least one input gear fixedly arranged on the second input shaft may comprise a first input gear operated at a second forward gear or a reverse gear, and a second input gear operated at a fourth forward gear or a sixth forward gear, wherein the first and second input gears are arranged in the stated order from a front side to a rear side of the second input shaft.

[0026] In further developments, the at least one input gear, which is fixedly arranged on the first input shaft, can have a third input gear, which is operated at a seventh forward gear, a fourth input gear, which is operated at a first forward gear, a fifth input gear, which is operated at a fifth forward gear, and a sixth input gear, which is operated at a third forward gear, wherein the third, the fourth, the fifth and the sixth input gear are arranged in the named order from a front side to a rear side of the first input shaft.

[0027] The gear output device may comprise: a first gear output unit having a first output shaft arranged in parallel with the first and second input shafts, and first and second synchronization modules arranged on the first output shaft, wherein the first gear output unit selectively connects four gear gears to the first output shaft by selective operation of the first and second synchronization modules and outputs the torque as four gears;a second gear output unit having a second output shaft arranged in parallel with the first and second input shafts, and third and fourth synchronization modules arranged on the second output shaft, the second gear output unit selectively connecting other four gears to the second output shaft through selective operation of the third and fourth synchronization modules and outputting torque as other four gears; and a reverse gear output unit having a reverse gear shaft and an idle gear arranged on the reverse gear shaft and meshing with any one of the input gears on the second input shaft and any one of the speed gears on the second output shaft.

[0028] The first synchronization module may selectively connect the second gear meshing with the first input gear or the sixth gear meshing with the second input gear to the first output shaft.

[0029] The second synchronization module may selectively connect the first gear meshing with the fourth input gear or the third gear meshing with the sixth input gear to the first output shaft.

[0030] The third synchronization module may selectively connect the reverse gear meshing with the idle gear or the fourth gear meshing with the second input gear to the second output shaft.

[0031] The idle gear may mesh with the first input gear of the second input shaft.

[0032] The idle gear may include a large (or larger) diameter gear and a small (or smaller) diameter gear disposed on the reverse shaft, the large diameter gear meshing with the first input gear and the small diameter gear meshing with the reverse gear.

[0033] The fourth synchronization module may selectively connect the seventh gear meshing with the third input gear or the fifth gear meshing with the fifth input gear to the second output shaft.

[0034] The devices of the present invention have other features and advantages as will become apparent in further detail from the attached drawings, which are incorporated herein, and the following detailed description, which together serve to explain certain principles of the present invention. Fig. 1 is a schematic diagram of an exemplary power transmission device for a vehicle according to the present invention. Fig. 2 is an operation table of the power transmission device of Fig. 1.

[0035] Reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with the exemplary embodiments, it is to be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, and other embodiments falling within the scope of the invention as defined in the appended claims.

[0036] A description of components which are not necessary for explaining the various embodiments is omitted, and the same components are provided with the same reference numerals in these documents.

[0037] In the detailed description, serial numbers are used to distinguish components that have the same name and have no special meaning.

[0038] Fig. 1 is a schematic diagram of an exemplary power transmission device for a vehicle according to various embodiments of the present invention.

[0039] Referring to Fig. 1 comprises a power transmission device according to various embodiments of the present invention: an electric auxiliary drive unit 2, a torque conversion device PG, an input device 8, 10, a variable linkage device CL1, CL2 and a gear output device OUT1, OUT2, REOUT.

[0040] The electric auxiliary drive unit comprises an electric motor generator 2 which is used in a conventional electric vehicle, and the electric motor generator 2 has a rotor 4 and a stator 6 to function simultaneously as a motor (or electric motor) and a generator.

[0041] The rotor 4 is connected to any rotating element of the torque conversion device, and the stator 6 is fixed to a gear housing H.

[0042] The torque conversion device comprises a planetary gear PG. In various embodiments of the present invention, a double-pinion planetary gear having three rotating elements is used as the torque conversion device.

[0043] The three rotation elements are a first rotation element N1, which consists of a sun gear S, a second rotation element N2, which consists of a planet carrier PC, and a third rotation element N3, which consists of a ring gear R.

[0044] The first rotating element N1 is connected to the rotor 4 to receive a torque of the rotor 4 or to transmit a torque to the rotor 4.

[0045] The second rotating element N2 is directly connected to an output shaft (or driven shaft) OS of an internal combustion engine ENG, which is a driving force source, to operate as an input element (or drive element). Additionally, the second rotating element N2 transmits a rotational speed of the output shaft OS to the gear output device.

[0046] The third rotary element N3 is operated as an output element which transmits a torque to the gear output device.

[0047] The input device has a first input shaft 8 and a second input shaft 10.

[0048] The first input shaft 8 is a hollow shaft, and a front end portion of the first input shaft 8 is selectively connected to the second rotational element N2 of the torque conversion device. The second input shaft 10 is inserted into the first input shaft 8 without rotationally interfering with the first input shaft 8. A front end portion of the second input shaft 10 is directly connected to the third rotational element N3 of the torque conversion device.

[0049] First, second, and third input gears G1, G2, and G3 are arranged on the first input shaft 8 at predetermined intervals. The first, second, and third input gears G1, G2, and G3 are arranged in an order of the first, second, and third input gears G1, G2, and G3 from a front side (e.g., near the engine or the clutches) to a rear side.

[0050] Fourth, fifth, sixth, and seventh input gears G4, G5, G6, and G7 are arranged on the second input shaft 10 at predetermined intervals. The fourth, fifth, sixth, and seventh input gears G4, G5, G6, and G7 are arranged at a rear portion of the second input shaft 10, which penetrates the first input shaft 8, and are arranged in an order of the fourth, fifth, sixth, and seventh input gears G4, G5, G6, and G7 from a front side to a rear side.

[0051] The first, second, third, fourth, fifth, sixth, and seventh input gears G1, G2, G3, G4, G5, G6, and G7 are input gears that operate in the respective gears. That is, the first input gear G1 operates at a first forward gear, the second input gear G2 operates at a seventh forward gear, the third input gear G3 operates at third and fifth forward gears, the fourth input gear G4 operates at a fourth forward gear, the fifth input gear G5 operates at a second forward gear, the sixth input gear G6 operates at a reverse gear, and the seventh input gear G7 operates at a sixth forward gear.

[0052] In addition, the input gears for odd gears are arranged on the first input shaft 8, and the input gears for even gears and a reverse gear are arranged on the second input shaft 10.

[0053] The variable connection device has a first clutch CL1 and a second clutch CL2.

[0054] The first clutch CL1 is arranged between the first input shaft 8 and the second rotary element N2 and selectively transmits the torque of the torque conversion device to the first input shaft 8.

[0055] The second clutch CL2 is arranged between the second input shaft 10 and the second rotating element N2 and selectively puts the planetary gear PG, which is the torque conversion device, into a direct coupling state.

[0056] The first and second clutches CL1 and CL2 may be conventional wet-type multi-disk clutches and are controlled by a hydraulic control system. Furthermore, the first and second clutches CL1 and CL2 may be dry-type multi-disk clutches.

[0057] The gear output device is configured to receive torque from each input gear, convert the torque, and output the converted torque. The gear output device includes first and second gear output units OUT1 and OUT2, and a reverse gear output unit REOUT, which are arranged at predetermined intervals from and parallel to the first and second input shafts 8 and 10.

[0058] The first gear output unit OUT1 has a first output shaft 12 which is arranged at a predetermined distance from the first and second input shafts 8 and 10 and parallel thereto, a first, a second, a third and a sixth gear gear D1, D2, D3 and D6, a first synchronization module SL1 which is arranged on the first output shaft 12 and selectively connects the first gear gear D1 or the third gear gear D3 to the first output shaft 12, and a second synchronization module SL2 which is arranged on the first output shaft 12 and selectively connects the second gear gear D2 or the sixth gear gear D6 to the first output shaft 12.

[0059] The first gear D1 is in mesh with the first input gear G1, and the third gear D3 is in mesh with the third input gear G3.

[0060] The second gear D2 is in mesh with the fifth input gear G5, and the sixth gear D6 is in mesh with the seventh input gear G7.

[0061] Furthermore, the torque converted by the first gear output unit OUT1 is transmitted to a conventional differential device via a first output gear mounted on a front or rear end portion of the first output shaft 12.

[0062] The second gear output unit OUT2 has a second output shaft 14 which is arranged at a distance from the first and second input shafts 8 and 10 and parallel thereto, a fourth, a fifth and a seventh gear D4, D5 and D7 and a reverse gear RG, a third synchronization module SL3 which is arranged on the second output shaft 14 and selectively connects the fifth gear D5 or the seventh gear D7 to the second output shaft 14, and a fourth synchronization module SL4 which is arranged on the second output shaft 14 and selectively connects the fourth gear D4 or the reverse gear RG to the second output shaft 14.

[0063] The seventh gear D7 is in mesh with the second input gear G2, and the fifth gear D5 is in mesh with the third input gear G3.

[0064] The fourth speed gear D4 is engaged with the fourth input gear G4, and the reverse gear RG is engaged with an idle gear ID of the reverse output unit REOUT.

[0065] Further, the torque converted by the second gear output unit OUT2 is transmitted to the conventional differential device via a second output gear mounted on a front or rear end portion of the second output shaft 14.

[0066] The reverse gear output unit REOUT has an idle gear ID which is integrally formed with a reverse gear shaft 16.

[0067] The idle gear ID is simultaneously meshed with the sixth input gear G6 and the reverse gear RG. Therefore, when the second input shaft 10 rotates, torque from the sixth input gear G6 is transmitted to the reverse gear RG via the idle gear ID, and the converted torque is transmitted to the conventional differential device via the second output gear of the second output shaft 14. At this time, a reverse speed is output.

[0068] Since the first, second, third, and fourth synchronization modules SL1, SL2, SL3, and SL4 are well known to those skilled in the art, a detailed description thereof will be omitted. Additionally, sleeves (e.g., shift sleeves) SLE1, SLE2, SLE3, and SLE4 are applied to the first, second, third, and fourth synchronization modules SL1, SL2, SL3, and SL4. As is well known to those skilled in the art, these are operated by means of additional actuators, and the actuators are controlled by a transmission control unit.

[0069] Fig. 2 is an operation table of the power transmission device of Fig. 1.

[0070] Referring to Fig.2, the first clutch CL1 is operated in odd gears, and the second clutch CL2 is operated in reverse, even gears, and boost. The sleeves SLE1, SLE2, SLE3, and SLE4 of the first, second, third, and fourth synchronization modules SL1, SL2, SL3, and SL4 are operatively coupled to the gears D1, D2, D3, D4, D5, D6, D7, and RG of the respective gears. Neutral

[0071] In a neutral N state, the first output shaft 12 and the second gear D2 are operatively connected by means of the sleeve SLE2 of the second synchronization module SL2, or another synchronization module is not in operation.

[0072] The reason why the first output shaft 12 and the second gear D2 are operatively connected in the neutral N state is that the vehicle is started not at the first forward gear but at the second forward gear.

[0073] Furthermore, when charging a battery in neutral N-state, the second clutch CL2 is operated to place the torque conversion device in the direct coupling state. In this case, the engine torque is transmitted to the rotor 4 to effectively charge the battery. Reverse gear

[0074] When the vehicle is started in reverse gear REV, the second output shaft 14 and the reverse gear RG are operatively connected via the sleeve SLE4 of the fourth synchronizer module SL4 before the second clutch CL2 is operated, and start control of the engine ENG and the electric motor generator 2 is executed. After that, shifting to the reverse gear REV is completed by the operation of the second clutch CL2. First forward gear

[0075] The first output shaft 12 and the second speed gear D2 are operatively connected by means of the sleeve SLE2 of the second synchronization module SL2 when the vehicle is started in a D range (or forward drive range), and the start control of the internal combustion engine ENG and the electric motor generator 2 is executed.

[0076] After the first output shaft 12 and the first gear D1 are operatively connected by means of the sleeve SLE1 of the first synchronization module SL1 while the vehicle is started, a shift to the first forward gear is completed by operation of the first clutch CL1. Second forward gear

[0077] The first clutch CL1, which was operating during the first forward gear, is disengaged, and the sleeve SLE1 of the first synchronization module SL1 is moved to a neutral position during the second forward gear. Afterward, when the second clutch CL2 is engaged, a shift to the second forward gear is completed. Third forward gear

[0078] The second clutch CL2, which was operating during the second forward gear, is disengaged, and the first output shaft 12 and the third gear D3 are operatively connected via the sleeve SLE1 of the first synchronization module SL1. Afterward, when the first clutch CL1 is engaged, a shift to the third forward gear is completed.

[0079] At this time, the first output shaft 12 and the second gear wheel D2 are operatively connected by means of the sleeve SLE2 of the second synchronization module SL2, but this has no effect on the shifting. Fourth forward gear

[0080] The first clutch CL1, which was operating at the third forward gear, is disengaged, and the sleeve SLE1 of the first synchronization module SL1 and the sleeve SLE2 of the second synchronization module SL2 are moved to their neutral positions. Thereafter, when the second output shaft 14 and the fourth gear D4 are operatively connected via the sleeve SLE4 of the fourth synchronization module SL4 and the second clutch CL2 is operated, a shift to the fourth forward gear is completed. Fifth forward gear

[0081] The second clutch CL2, which was operating at the fourth forward gear, is disengaged, and the second output shaft 14 and the fifth gear D5 are operatively connected via the sleeve SLE3 of the third synchronization module SL3. Afterward, when the first clutch CL1 is engaged, a shift to the fifth forward gear is completed.

[0082] At this time, the second output shaft 14 and the fourth gear D4 are operatively connected by means of the sleeve SLE4 of the fourth synchronization module SL4, but this has no effect on the shifting. Sixth forward gear

[0083] The first clutch CL1, which was operating at the fifth forward gear, is disengaged, and the sleeve SLE3 of the third synchronization module SL3 and the sleeve SLE4 of the fourth synchronization module SL4 are moved to their neutral positions. Thereafter, when the first output shaft 12 and the sixth-speed gear D6 are operatively connected via the sleeve SLE2 of the second synchronization module SL2 and the second clutch CL2 is operated, a shift to the sixth forward gear is completed. Seventh forward gear

[0084] The second clutch CL2, which was operating at the sixth forward gear, is disengaged, and the second output shaft 14 and the seventh gear D7 are operatively connected via the sleeve SLE3 of the third synchronization module SL3. Afterward, when the first clutch CL1 is engaged, a shift to the seventh forward gear is completed.

[0085] At this time, the first output shaft 12 and the sixth gear D6 are operatively connected by means of the sleeve SLE2 of the second synchronization module SL2, but this has no effect on the shifting.

[0086] Further, when the electric motor generator 2, which is the electric auxiliary drive unit, is driven in a state in which the second clutch CL2 is not operated, the torque conversion device changes and outputs the torque according to rotational speeds of the electric motor generator 2 and the engine ENG.

[0087] When the electric motor generator 2, which is the electric auxiliary drive unit, is in operation when the vehicle is running in the forward gears and in reverse gear, regenerative braking is possible.

[0088] According to various embodiments of the present invention, starting and shifting are achieved by utilizing the electric motor-generator, which is the auxiliary electric drive unit, and the planetary gear set, which is the torque conversion device. Therefore, smooth starting and shifting can be achieved.

[0089] Since clutch slippage can be minimized and regenerative braking is possible during deceleration, fuel economy can be improved.

[0090] Furthermore, since the electric motor generator, which is the electric auxiliary drive unit, assists torque during acceleration, the acceleration performance can be improved.

[0091] For the purpose of explanation and accurate definition of the appended claims, terms such as "front", "rear", etc., are used to describe the features of the exemplary embodiments with reference to the positions of such features as illustrated in the figures.

[0092] The foregoing descriptions of the specific exemplary embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, and to enable those skilled in the art to make and use the various embodiments of the present invention, as well as numerous alternatives and modifications thereof. It is intended that the scope of the invention be defined by the appended claims.

Claims

[1] A power transmission device for a vehicle, comprising: an auxiliary electric drive unit (2) which is operated as an electric motor or a generator; a torque conversion device comprising a planetary gear (PG) having a first, a second and a third rotation element (N1, N2, N3), wherein the first rotation element (N1) is connected to the electric auxiliary drive unit (2), the second rotation element (N2) is connected to an internal combustion engine (ENG), and the third rotation element (N3) is operated as an output element; an input device comprising: a first input shaft (8) which is selectively connected to the second rotational element (N2) by means of a clutch (CL1) and is provided with at least one input gear (G1, G2, G3) fixedly arranged thereon; and a second input shaft (10) which is arranged coaxially to the first input shaft (8) without rotationally impairing the first input shaft (8), is directly connected to the third rotational element (N3), is selectively connected to the second rotational element (N2) by means of a second clutch (CL2) and is provided with at least one input gear (G4, G5, G6, G7) fixedly arranged thereon; and a gear output device (OUT1, OUT2) which converts a torque of the input device and outputs the converted torque, wherein the gear output device (OUT1, OUT2) comprises a first and a second output shaft (12, 14) which are parallel to the first and to the second input shaft (8, 10), and a plurality of gear wheels (D1, D2, D3, D4, D5, D6, D7, RG), which are connected by means of Synchronization modules (SL1, SL2, SL3, SL4) arranged on the first and second output shafts (12, 14), operatively connected to the first output shaft (12) or the second output shaft (14), and wherein the first input shaft (8) is a hollow shaft and the second input shaft (10) penetrates the first input shaft (8) coaxially. [2] The power transmission device according to claim 1, wherein the auxiliary electric drive unit (2) comprises: a rotor (4) connected to the first rotating element (N1) of the torque conversion device; and a stator (6) which surrounds the rotor (4) and is fastened to a gear housing (H). [3] The power transmission device according to claim 1, wherein: the planetary gear (PG) is a planetary gear with double planet gears; the first rotating element (N1) is a sun gear (S); the second rotating element (N2) is a planetary gear carrier (PC); and the third rotation element (N3) is a ring gear (R). [4] The power transmission device according to claim 1, wherein: the at least one input gear fixedly arranged on the first input shaft (8) comprises a first input gear (G1) operated at a first forward gear, a second input gear (G2) operated at a seventh forward gear, and a third input gear (G3) operated at a fifth forward gear, wherein the first, second, and third input gears (G1, G2, G3) are arranged in the stated order from a front side to a rear side of the first input shaft (8); and the at least one input gear, which is fixedly arranged on the second input shaft (10), has a fourth input gear (G4) operated at a fourth forward gear, a fifth input gear (G5) operated at a second forward gear, a sixth input gear (G6) operated at a reverse gear, and a seventh input gear (G7) operated at a sixth forward gear, wherein the fourth, fifth, sixth and seventh input gears (G4, G5, G6, G7) are arranged in the named order from a front side to a rear side of the second input shaft (10). [5] The power transmission device according to claim 4, wherein the gear output device comprises: a first gear output unit (OUT1) having a first output shaft (12) arranged parallel to the first and second input shafts (8, 10), and first and second synchronization modules (SL1, SL2) arranged on the first output shaft (12), the first gear output unit (OUT1) selectively connecting four gear gears to the first output shaft (12) by means of a selective operation of the first and second synchronization modules (SL1, SL2) and outputting the torque as four gears; a second gear output unit (OUT2) having a second output shaft (14) arranged parallel to the first and second input shafts (8, 10), and third and fourth synchronization modules (SL3, SL4) arranged on the second output shaft (14), the second gear output unit (OUT2) selectively connecting other four gear gears to the second output shaft (14) by means of a selective operation of the third and fourth synchronization modules (SL3, SL4) and outputting the torque as other four gears; and a reverse gear output unit (REOUT) comprising a reverse gear shaft (16) and an idle gear (ID) disposed on the reverse gear shaft (16) and meshing with any input gear among the input gears on the second input shaft (10) and any speed gear among the speed gears on the second output shaft (14). [6] The power transmission device according to claim 5, wherein the first synchronization module (SL1) selectively connects the first speed gear (D1) meshing with the first input gear (G1) or the third speed gear (D3) meshing with the third input gear (G3) to the first output shaft (12). [7] The power transmission device according to claim 5, wherein the second synchronization module (SL2) selectively connects the second speed gear (D2) meshing with the fifth input gear (G5) or the sixth speed gear (D6) meshing with the seventh input gear (G7) to the first output shaft (12). [8] The power transmission device according to claim 5, wherein the third synchronization module (SL3) selectively connects the seventh speed gear (D7) meshing with the second input gear (G2) or the fifth speed gear (D5) meshing with the third input gear (G3) to the second output shaft (14). [9] The power transmission device according to claim 5, wherein the fourth synchronization module (SL4) selectively connects the fourth speed gear (D4) meshing with the fourth input gear (G4) or a reverse gear (RG) meshing with the idle gear (ID) to the second output shaft (14). [10] The power transmission device according to claim 9, wherein the idle gear (ID) is engaged with the sixth input gear (G6) of the second input shaft (10). [11] The power transmission device according to claim 1, wherein: the at least one input gear fixedly arranged on the second input shaft (10) comprises a first input gear (G1) operated at a second forward gear or a reverse gear, and a second input gear (G2) operated at a fourth forward gear or a sixth forward gear, wherein the first and second input gears (G1, G2) are arranged in the said order from a front side to a rear side of the second input shaft (10); and the at least one input gear, which is fixedly arranged on the first input shaft (8), has a third input gear (G3) which is operated at a seventh forward gear, a fourth input gear (G4) which is operated at a first forward gear, a fifth input gear (G5) which is operated at a fifth forward gear, and a sixth input gear (G6) which is operated at a third forward gear, wherein the third, fourth, fifth and sixth input gears (G3, G4, G5, G6) are arranged in the named order from a front side to a rear side of the first input shaft (8). [12] The power transmission device according to claim 11, wherein the gear output device comprises: a first gear output unit (OUT1) having a first output shaft (12) arranged parallel to the first and second input shafts (8, 10), and first and second synchronization modules (SL1, SL2) arranged on the first output shaft (12), the first gear output unit (OUT1) selectively connecting four gear wheels to the first output shaft (12) by means of a selective operation of the first and second synchronization modules (SL1, SL2) and outputting the torque as four gears; a second gear output unit (OUT2) having a second output shaft (14) arranged parallel to the first and second input shafts (8, 10), and third and fourth synchronization modules (SL3, SL4) arranged on the second output shaft (14), the second gear output unit (OUT2) selectively connecting other four gear gears to the second output shaft (14) by means of a selective operation of the third and fourth synchronization modules (SL3, SL4) and outputting the torque as other four gears; and a reverse gear output unit (REOUT) comprising a reverse gear shaft (16) and an idle gear disposed on the reverse gear shaft (16) and meshing with any input gear among the input gears on the second input shaft (10) and any speed gear among the speed gears on the second output shaft (14). [13] The power transmission device according to claim 12, wherein the first synchronization module (SL1) selectively connects the second speed gear (D2) meshing with the first input gear (G1) or the sixth speed gear (D6) meshing with the second input gear (G2) to the first output shaft (12). [14] The power transmission device according to claim 12, wherein the second synchronization module (SL2) selectively connects the first speed gear (D1) meshing with the fourth input gear (G4) or the third speed gear (D3) meshing with the sixth input gear (G6) to the first output shaft (12). [15] The power transmission device according to claim 12, wherein the third synchronization module (SL3) selectively connects the reverse gear (RG) meshing with the idle gear or the fourth speed gear (D4) meshing with the second input gear (G2) to the second output shaft (14). [16] The power transmission device according to claim 15, wherein the idle gear is engaged with the first input gear (G1) of the second input shaft (10). [17] The power transmission device according to claim 16, wherein the idle gear comprises a large diameter gear (18) and a small diameter gear (20) arranged on the reverse shaft (16), the large diameter gear (18) being engaged with the first input gear (G1) and the small diameter gear (20) being engaged with the reverse gear (RG). [18] The power transmission device according to claim 12, wherein the fourth synchronization module (SL4) selectively connects the seventh speed gear (D7) meshing with the third input gear (G3) or the fifth speed gear (D5) meshing with the fifth input gear (G5) to the second output shaft (14).

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