Hybrid powertrains for vehicles

Abstract

The present invention relates to a hybrid powertrain for a vehicle. The hybrid powertrain may include: an engine input shaft connected to the engine via a main clutch; an electric motor input shaft coaxially mounted with the engine input shaft and engaged with the electric motor; a central synchronizer mounted to interrupt the connection between the engine input shaft and the electric motor input shaft; the first and second output shafts mounted parallel to the engine input shaft; the variable drive gear disposed on the electric motor input shaft to maintain or increase the rotational speed of the electric motor input shaft and then transmit the maintained or increased rotational speed to the first output shaft; and the multiple external gear pairs mounted to form different transmission gear ratios between the engine input shaft and the first output shaft and between the engine input shaft and the second output shaft.

Description

Technical Field

[0001] The present invention relates to a hybrid powertrain layout suitable for a vehicle. Background Art

[0002] Automated manual transmissions (AMTs) are generally considered the most competitive among automatic transmissions in terms of production cost, material cost, and fuel efficiency, but have not been widely adopted due to reduced vehicle marketability caused by torque interruption during gear shifting.

[0003] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0004] Various aspects of the present invention are intended to provide a hybrid powertrain that, while enhancing the advantages of an AMT, can improve shift feel by utilizing an electric motor to eliminate torque interruption, which is a disadvantage of an automated manual transmission (AMT), and can eliminate the clutch between the electric motor and the engine required in a conventional hybrid powertrain (in which the electric motor is located between the engine and the transmission), thereby improving the installation convenience of the transmission in a vehicle due to the reduction in the overall length of the transmission, reducing the weight and production cost of the transmission, and helping to improve the fuel efficiency of the vehicle.

[0005] According to various aspects of the present invention, the above and other objects can be achieved by providing a hybrid powertrain for a vehicle, comprising: an engine input shaft connected to the engine via a main clutch; an electric motor input shaft; a central synchronizer; a first output shaft; a second output shaft; a variable drive gear; and a plurality of external gear pairs, wherein the engine input shaft is connected to the engine via a main clutch; the electric motor input shaft is mounted coaxially with the engine input shaft and engaged with the electric motor; the central synchronizer is mounted to interrupt the connection between the engine input shaft and the electric motor input shaft; the first output shaft and the second output shaft are both mounted parallel to the engine input shaft; the variable drive gear is disposed on the electric motor input shaft to maintain or increase the rotational speed of the electric motor input shaft and then transmit the maintained or increased rotational speed to the first output shaft; the plurality of external gear pairs are mounted to form different transmission ratios between the engine input shaft and the first output shaft and between the engine input shaft and the second output shaft; wherein the plurality of transmission ratios formed by the plurality of external gear pairs and the two transmission ratios formed when the variable drive gear transmits power to the first output shaft form a series of different transmission ratios for driving the vehicle.

[0006] The variable drive gear can be mounted on the motor input shaft via a one-way clutch, wherein the one-way clutch is configured to transmit power in a direction from the motor input shaft to the variable drive gear, and the variable drive gear can be integrally connected to a third rotating element of a planetary gear set, wherein the planetary gear set includes: a first rotating element that is configured to be fixed to a transmission housing via a brake, and a second rotating element connected to the motor input shaft.

[0007] The variable drive gear can be configured to be locked to the motor input shaft via a central synchronizer.

[0008] The central synchronizer may include: a hub and a sleeve, wherein the hub is mounted on the motor input shaft; the sleeve is mounted to be slidable on the hub along the axial direction of the motor input shaft and is configured such that: when the sleeve moves to one side of the hub, the hub is directly connected to the engine input shaft; when the sleeve moves to the other side of the hub, the hub is directly connected to the variable drive gear.

[0009] The central synchronizer may be connected to the engine input shaft by being provided in the form of a synchronizer configured to perform synchronization interaction using a synchronizer ring, and may be connected to the variable drive gear by being provided in the form of a dog clutch.

[0010] The external gear pair between the engine input shaft and the first output shaft can be installed to achieve the transmission transmission ratio of the second gear and the transmission transmission ratio of the sixth gear, the external gear pair between the engine input shaft and the second output shaft can be installed to achieve the transmission transmission ratio of the first gear and the transmission transmission ratio of the fourth gear, and the variable drive gear can be installed to transmit power to the first output shaft with the transmission transmission ratio of the third gear and the transmission transmission ratio of the fifth gear.

[0011] The first drive gear and the second drive gear can be installed on the engine input shaft, the first drive gear is commonly used to achieve the transmission transmission ratio of the first gear and the transmission transmission ratio of the second gear, the second drive gear is commonly used to achieve the transmission transmission ratio of the fourth gear and the transmission transmission ratio of the sixth gear, the driven gear of the second gear meshing with the first drive gear and the driven gear of the sixth gear meshing with the second drive gear can be installed on the first output shaft, the driven gear of the first gear meshing with the first drive gear and the driven gear of the fourth gear meshing with the second drive gear can be installed on the second output shaft.

[0012] The first drive gear and the second drive gear can be installed on the engine input shaft so that the rotation of the first drive gear and the rotation of the second drive gear are locked on the engine input shaft, the second and sixth gear synchronization devices can be set on the first output shaft, and the second and sixth gear synchronization devices are configured to selectively lock the rotation of the driven gear of the second gear and the rotation of the driven gear of the sixth gear on the first output shaft, and the first and fourth gear synchronization devices can be set on the second output shaft, and the first and fourth gear synchronization devices are configured to selectively lock the rotation of the driven gear of the first gear and the rotation of the driven gear of the fourth gear on the second output shaft.

[0013] A clutch gear configured to form a portion of the central synchronizer may be integrally provided on the second drive gear.

[0014] The first output gear may be disposed on the first output shaft, the second output gear may be disposed on the second output shaft, and the first output gear and the second output gear may be commonly engaged with the ring gear of the differential device.

[0015] A motor driven gear configured to receive power from the motor may be provided integrally with the motor input shaft, and a motor driving gear provided on a rotation shaft of the motor may be engaged with the motor driven gear.

[0016] The rotating shaft of the motor can be directly connected to the motor input shaft.

[0017] The motor input shaft may be connected to the motor through a planetary gear set for reducing a rotation speed of the motor and then transmitting the reduced rotation speed to the motor input shaft.

[0018] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram illustrating a hybrid powertrain of a vehicle according to an exemplary embodiment of the present invention;

[0020] 2A, 2B, 2C, 2D and 2E are diagrams showing Figure 1 A schematic diagram of a process of shifting from a first gear to a second gear in a powertrain of FIG.

[0021] 3A, 3B, 3C, 3D and 3E are diagrams showing Figure 1 A schematic diagram of a process of shifting from the second gear to the third gear in a powertrain of FIG.

[0022] 4A, 4B, 4C, 4D and 4E are diagrams showing Figure 1 A schematic diagram of a process of shifting from third gear to fourth gear in a powertrain of FIG.

[0023] 5A, 5B, 5C, 5D and 5E are diagrams showing Figure 1 Schematic diagram of a process of shifting from fourth gear to fifth gear in a powertrain of ;

[0024] 6A, 6B, 6C, 6D and 6E are diagrams showing Figure 1 Schematic diagram of a process of shifting from fifth gear to sixth gear in a powertrain of ;

[0025] 7A, 7B and 7C are diagrams showing the operation of the vehicle in an electric vehicle mode. Figure 1 A schematic diagram of a process of shifting from a first gear to a second gear in a powertrain of FIG.

[0026] 8A, 8B and 8C are diagrams showing the electric vehicle mode. Figure 1 A schematic diagram of a process of shifting from the second gear to the first gear in a powertrain of FIG.

[0027] Figure 9 is a schematic diagram illustrating a hybrid powertrain of a vehicle according to various exemplary embodiments of the present invention;

[0028] Figure 10 is a schematic diagram illustrating a hybrid power train of a vehicle according to another exemplary embodiment of the present invention.

[0029] It should be understood that the accompanying drawings are not necessarily drawn to scale, but rather show a somewhat simplified representation of various features illustrating the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the specific intended application and use environment.

[0030] In the figures, like reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0031] Reference will now be made in detail to various specific embodiments of the present invention, examples of which are presented in the accompanying drawings and described below. Although the present invention will be described in conjunction with exemplary embodiments thereof, it should be appreciated that this description is not intended to limit the present invention to those exemplary embodiments. On the other hand, the present invention is intended to cover not only the exemplary embodiments of the present invention, but also various alternative forms, modifications, equivalent forms, and other embodiments that may be included within the spirit and scope of the present invention as defined by the appended claims.

[0032] Reference will now be made in detail to the exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0033] refer to Figure 1 According to an exemplary embodiment of the present invention, a hybrid powertrain of a vehicle includes: an engine input shaft EI, a motor input shaft MI, a central synchronizer CS, a first output shaft OUT1, a second output shaft OUT2, a variable drive gear VD and a plurality of external gear pairs; the engine input shaft EI is connected to the engine E through a main clutch MC; the motor input shaft MI is installed to be coaxial with the engine input shaft EI and connected to the motor M; the central synchronizer CS is installed to interrupt the connection between the engine input shaft EI and the motor input shaft MI; the first output shaft OUT1 and the second output shaft OUT2 are installed to be parallel to the engine input shaft EI; the variable drive gear VD is provided on the motor input shaft MI to maintain or increase the rotation speed of the motor input shaft MI, and then transmit the maintained or increased rotation speed to the first output shaft OUT1; the plurality of external gear pairs are installed to form different transmission gear ratios between the engine input shaft EI and the first output shaft OUT1 and between the engine input shaft EI and the second output shaft OUT2.

[0034] The plurality of transmission ratios formed by the plurality of external gear pairs and the two transmission ratios formed when the variable drive gear VD transmits power to the first output shaft OUT1 form a series of different transmission ratios for driving the vehicle.

[0035] That is, in an exemplary embodiment of the present invention, multiple external gear pairs are arranged to form transmission ratios of the first gear, the second gear, the fourth gear and the sixth gear. When the variable drive gear VD maintains the rotation speed of the motor input shaft MI and thus transmits the maintained rotation speed, the variable drive gear VD forms the transmission ratio of the third gear. When the variable drive gear VD increases the rotation speed of the motor input shaft MI and thus transmits the increased rotation speed, the variable drive gear VD forms the transmission ratio of the fifth gear. Thus, the vehicle can achieve a series of transmission ratios, namely, the transmission ratios of the first gear to the sixth gear.

[0036] As described below, the powertrain according to an exemplary embodiment of the present invention can utilize the power of the engine E (which is received by the engine input shaft EI through the main clutch MC) through multiple external gear pairs and the variable drive gear VD to achieve the first forward gear to the sixth forward gear, and perform smooth gear shifting without torque interruption caused by gear shifting.

[0037] The variable drive gear VD is mounted on the motor input shaft MI via a one-way clutch OWC, which transmits power only in the direction from the motor input shaft MI to the variable drive gear VD.

[0038] Therefore, the power of the motor input shaft MI drives the variable drive gear VD only when the motor input shaft MI rotates in the forward direction at a speed higher than that of the variable drive gear VD.

[0039] Here, the forward direction refers to a direction in which the motor input shaft MI and the engine input shaft EI rotate to drive the vehicle forward.

[0040] In addition, the variable drive gear VD is integrally connected to the third rotation element of the planetary gear set PG including a first rotation element provided to be fixable by a brake BK and a second rotation element connected to the motor input shaft MI.

[0041] Here, the first rotation element of the planetary gear set PG is the sun gear S, the second rotation element is the planet carrier, and the third rotation element is the ring gear R.

[0042] That is, the variable drive gear VD is installed on the motor input shaft MI through the planetary gear set PG and the one-way clutch OWC, so that the rotation speed of the motor input shaft MI can be maintained or increased, and then the power of the motor input shaft MI with the maintained or increased rotation speed is transmitted to the first output shaft OUT1.

[0043] When the brake BK is not engaged, when the motor input shaft MI rotates in the forward direction at a speed higher than the variable drive gear VD, power is transmitted from the motor input shaft MI to the variable drive gear VD, the variable drive gear VD transmits the power of the motor input shaft MI to the first output shaft OUT1 without changing the rotation speed of the motor input shaft MI, and the planetary carrier C of the planetary gear set PG is directly connected to the motor input shaft MI; therefore, in the above situation, the entire planetary gear set PG rotates at the same speed as the variable drive gear VD.

[0044] When the brake BK is engaged, the sun gear S of the planetary gear set PG is fixed to the transmission housing H, so that the power of the motor input shaft MI transmitted to the planetary carrier C drives the ring gear R and the variable drive gear VD at an increased speed, and transmits the power of the motor input shaft MI with the increased rotation speed to the first output shaft OUT1; therefore, in the above situation, the one-way clutch OWC causes the variable drive gear VD to rotate at a speed higher than that of the motor input shaft MI.

[0045] The variable drive gear VD is configured to be locked to the motor input shaft MI via a central synchronizer CS.

[0046] That is, the central synchronizer CS includes: a hub portion and a sleeve SB, wherein the hub portion is mounted on the motor input shaft MI, and the sleeve SB is mounted to be slidable in the axial direction on the hub portion HB and is configured to: when the sleeve SB moves to one side, it is directly connected to the engine input shaft EI; when the sleeve SB moves to the other side, it is directly connected to the variable drive gear VD.

[0047] For reference, the "axial direction" refers to the longitudinal direction of the motor input shaft MI.

[0048] The central synchronizer CS is connected to the engine input shaft EI by means of a synchronizer device configured to perform synchronization interaction using a synchronizer ring, and is connected to the variable drive gear VD by means of a dog clutch.

[0049] In an exemplary embodiment of the present invention, the clutch gear CG constituting a part of the central synchronizer CS is integrally arranged on the engine input shaft EI with the second drive gear DG2 to be described later, and the clutch gear CG is configured to directly connect the engine input shaft EI to the motor input shaft MI through the engaging sleeve SB and the clutch gear CG.

[0050] In addition, a synchronizer ring is provided between the clutch gear CG of the second drive gear DG2 and the sleeve SB, and the sleeve SB is engaged with the clutch gear CG of the second drive gear DG2 through the synchronizing interaction of the synchromesh type synchronizer.

[0051] For reference, a synchronizer ring is generally used in a conventional synchromesh type synchronizer, and thus illustration thereof will be omitted in the drawings.

[0052] As described above, the central synchronizer CS is connected to the variable drive gear VD by being arranged in the form of a dog clutch, since the synchronization interaction is actively performed by the motor M and the brake BK.

[0053] Of course, the clutch gear CG is provided integrally with the variable drive gear VD so that when the sleeve SB moves to the other side ( Figure 1 (to the right in the figure), the sleeve SB engages with the clutch gear CG.

[0054] The external gear pair between the engine input shaft EI and the first output shaft OUT1 is installed to achieve the transmission transmission ratio of the second gear and the transmission transmission ratio of the sixth gear, the external gear pair between the engine input shaft EI and the second output shaft OUT2 is installed to achieve the transmission transmission ratio of the first gear and the transmission transmission ratio of the fourth gear, and the drive gear VD is installed to transmit power to the first output shaft OUT1 with the transmission transmission ratio of the third gear and the transmission transmission ratio of the fifth gear.

[0055] That is, the first drive gear DG1 (which is commonly used to achieve the transmission transmission ratio of the first gear and the transmission transmission ratio of the second gear) and the second drive gear DG2 (which is commonly used to achieve the transmission transmission ratio of the fourth gear and the transmission transmission ratio of the sixth gear) are installed on the engine input shaft EI, the driven gear P2 of the second gear (which is engaged with the first drive gear DG1) and the driven gear P6 of the sixth gear (which is engaged with the second drive gear DG2) are installed on the first output shaft OUT1, and the driven gear P1 of the first gear (which is engaged with the first drive gear DG1) and the driven gear P4 of the fourth gear (which is engaged with the second drive gear DG2) are installed on the second output shaft OUT2.

[0056] The first drive gear DG1 and the second drive gear DG2 are mounted on the engine input shaft EI so that the rotation of the first drive gear DG1 and the second drive gear DG2 is locked on the engine input shaft EI, the second and sixth gear synchronizer devices 2&6S are arranged on the first output shaft OUT1, and the second and sixth gear synchronizer devices 2&6S are configured to selectively lock the rotation of the driven gear P2 of the second gear and the driven gear P6 of the sixth gear on the first output shaft OUT1, the first and fourth gear synchronizer devices 1&4S are arranged on the second output shaft OUT2, and the first and fourth gear synchronizer devices 1&4S are configured to selectively lock the rotation of the driven gear P1 of the first gear and the driven gear P4 of the fourth gear on the second output shaft OUT2.

[0057] In addition, the first output gear OG1 is provided on the first output shaft OUT1, and the second output gear OG2 is provided on the second output shaft OUT2. The first output gear OG1 and the second output gear OG2 are engaged with the ring gear RG of the differential device DF to output power to the driving wheels.

[0058] In addition, a variable driven gear VP meshing with the variable drive gear VD is mounted on the first output shaft OUT1 so that rotation of the variable driven gear VP is locked on the first output shaft OUT1 , and the variable driven gear VP is configured to transmit power from the variable drive gear VD to the first output shaft OUT1 .

[0059] exist Figure 1 In the exemplary embodiment shown, the above configuration is common to all embodiments of the present invention, and the motor driven gear MP for receiving power from the motor M is integrally arranged with the motor input shaft MI, and the motor drive gear MD arranged on the rotating shaft of the motor M is engaged with the motor driven gear MP.

[0060] Therefore, the rotational power of the motor M is changed by the gear ratio of the motor driving gear MD and the motor driven gear MP, and then transmitted to the motor input shaft MI.

[0061] exist Figure 9 In another exemplary embodiment shown, the rotating shaft of the motor M is directly connected to the motor input shaft MI.

[0062] Therefore, the driving power of the motor M directly drives the motor input shaft MI, and the power train according to the exemplary embodiment of the present invention may require only a minimum number of parts and have a minimized and compact configuration.

[0063] exist Figure 10 In yet another exemplary embodiment shown, the motor input shaft MI is connected to the motor M via a speed reduction planetary gear set RPG that reduces the rotational speed of the motor M and transmits the reduced rotational speed of the motor M to the motor input shaft MI.

[0064] That is, in addition to the planetary gear set PG connected to the variable drive gear VD, a planetary gear set RPG for speed reduction is further provided. The planetary gear set RPG for speed reduction first reduces the rotation speed of the motor M and then transmits the reduced rotation speed to the motor input shaft MI.

[0065] The planetary gear set RPG for speed reduction includes a ring gear R fixed to a transmission housing H, a sun gear S connected to a motor shaft MS of a motor M, and a planet carrier C connected to a motor input shaft MI.

[0066] Hereinafter, the Figure 1 2 is a diagram illustrating a process of shifting from a first gear to a sixth gear in a power train according to an exemplary embodiment.

[0067] Figures 2A, 2B, 2C, 2D, and 2E are schematic diagrams illustrating the process of shifting from first gear to second gear. Figure 2A illustrates the vehicle driving in first gear, wherein the main clutch MC is engaged, the first and fourth gear synchronizers 1 & 4S connect the first gear driven gear P1 to the second output shaft OUT2, the center synchronizer CS is in a neutral state, and the power of the engine E drives the engine input shaft EI through the main clutch MC.

[0068] Here, the power of the engine input shaft EI is transmitted to the second output shaft OUT2 through the first drive gear DG1 and the driven gear P1 of the first gear, and then the power of the engine input shaft EI is output while forming the transmission gear ratio of the first gear through the second output gear OG2 and the ring gear RG of the differential device DF.

[0069] As shown in FIG. 2B , when a command for instructing a shift to the second gear is given, the center synchronizer is engaged with the variable drive gear VD, and the motor M is driven.

[0070] As shown in FIG. 2C , the main clutch MC is released, and the power of the motor M is used to maintain the current driving state of the vehicle.

[0071] As shown in Figure 2D, in a state where the driven gear P2 in the second gear is locked on the first output shaft OUT1 by the second and sixth gear synchronizer devices 2&6S, the vehicle starts to travel in the second gear by engaging the main clutch MC, and, as shown in Figure 2E, by releasing the drive of the motor M, the vehicle enters a driving state of the second gear using only the engine E.

[0072] Thus, the gear shift is accomplished without torque interruption.

[0073] 3A, 3B, 3C, 3D and 3E are schematic diagrams illustrating a process of shifting from the second gear to the third gear. Fig. 3A shows a state where the center synchronizer CS changes from the state of Fig. 2E to an intermediate state.

[0074] As shown in FIG. 3B , when a command for instructing a shift to the third gear is given, the motor M is driven in preparation for cutting off the power from the engine E.

[0075] As shown in FIG. 3C , the main clutch MC is released, so that the driving state of the vehicle in the second gear is maintained using only the power of the motor M.

[0076] As shown in FIG3D , when the center synchronizer CS moves to the left, directly connecting the engine input shaft EI and the motor input shaft MI, and then engaging the main clutch MC, the vehicle enters the third gear driving state. As shown in FIG3E , when the motor M is disengaged from driving, the vehicle's driving state in the third gear is maintained solely by the engine E. During this shifting process, no torque interruption occurs.

[0077] 4A, 4B, 4C, 4D and 4E are schematic diagrams illustrating a process of shifting from the third gear to the fourth gear. Fig. 4A shows the same state as Fig. 3E.

[0078] As shown in FIG4B , when a command instructing a shift to fourth gear is issued, the motor M is activated. As shown in FIG4C , both the main clutch MC and the center synchronizer CS are released. As shown in FIG4D , the first and fourth gear synchronizer devices 1 & 4S connect the fourth gear driven gear P4 to the second output shaft OUT2 . By engaging the main clutch MC, the vehicle enters the fourth gear driving state. Then, as shown in FIG4E , the motor M is released, and the vehicle driving state in fourth gear is maintained solely by the engine E. Similarly, during this shifting process, no torque interruption occurs.

[0079] Figures 5A, 5B, 5C, 5D, and 5E are schematic diagrams illustrating a shift process from fourth gear to fifth gear. As shown in Figure 5A , when a command instructing a shift to fifth gear is given while the vehicle is being driven in fourth gear, as shown in Figure 5B , motor M is driven while brake BK is engaged, thereby additionally utilizing motor M to maintain the vehicle's drive state in fourth gear.

[0080] Here, since the rotation speed of the motor M is increased by the planetary gear set PG and the variable drive gear VD, and then the power of the motor M with the increased rotation speed is transmitted to the first output shaft OUT1, there is no need to increase the RPM of the motor M when the vehicle is traveling in the fourth gear.

[0081] As shown in FIG. 5C , the main clutch MC is released, and the first and fourth gear synchronizer devices 1 & 4S are released to a neutral state.

[0082] As shown in FIG5D , the motor input shaft MI is directly connected to the engine input shaft EI via the central synchronizer CS, and then the main clutch MC is engaged, causing the vehicle to enter the fifth gear driving state. Then, as shown in FIG5E , the motor M is disengaged, and the vehicle driving state in the fifth gear is maintained using only the engine E. Similarly, during this shifting process, no torque interruption occurs.

[0083] Figures 6A, 6B, 6C, 6D, and 6E are schematic diagrams illustrating a shift process from fifth gear to sixth gear. As shown in Figure 6A , while the vehicle is in the fifth gear driving state, when a command instructing a shift to the sixth gear is given, as shown in Figure 6B , the motor M is driven, thereby additionally utilizing the motor M to maintain the vehicle in the fifth gear driving state. Then, as shown in Figure 6C , the main clutch MC is released, and the center synchronizer CS is released to an intermediate state.

[0084] As shown in FIG. 6D , the second and sixth gear synchronizer 2 & 6S is engaged with the driven gear P6 of the sixth gear, and then the vehicle enters the driving state of the sixth gear by engaging the main clutch MC.

[0085] 6E , when the driving of the motor M is released, the vehicle is maintained in the driving state of the sixth gear using only the engine E. Similarly, during this gear shifting process, no torque interruption occurs.

[0086] That is, the hybrid power train according to the exemplary embodiment of the present invention can perform shifting from the first gear to the sixth gear without torque interruption, thereby being able to achieve excellent power transmission efficiency and shift quality.

[0087] For reference, in the drawing, a bold line indicates a portion where power is transmitted, and downshifting is performed through a process similar to the above-described upshifting process, so a detailed description thereof will be omitted.

[0088] Figures 7A, 7B, and 7C are schematic diagrams illustrating the process of shifting from first gear to second gear in the powertrain in an electric vehicle mode, where the vehicle is driven solely by motor M. As shown in Figure 7A , with brake BK released, motor M is driven to achieve a vehicle driving state in first gear using motor M. As shown in Figure 7B , when a command instructing a shift to second gear is issued, brake BK is engaged, and center synchronizer CS is released to an intermediate state, achieving a vehicle driving state in second gear using motor M.

[0089] In the state shown in FIG7A , even when the center synchronizer CS is not engaged with the variable drive gear VD, the vehicle can be driven in the first forward gear position by the one-way clutch OWC. However, as shown in FIG7A , when the center synchronizer CS is engaged with the variable drive gear VD, a reverse gear position can be achieved by rotating the motor M in the reverse direction.

[0090] Figures 8A, 8B, and 8C are schematic diagrams illustrating the process of shifting from second gear to first gear in the powertrain in electric vehicle mode. As shown in Figure 8A , when the vehicle is driven in second gear by the electric motor M and a command to shift to first gear is received, the variable drive gear VD is synchronized with the sleeve SB of the center synchronizer CS by controlling the release of the brake BK, as shown in Figure 8B , and the center synchronizer CS engages the clutch gear CG of the variable drive gear VD. Subsequently, as shown in Figure 8C , when the brake B is fully released, a downshift to first gear is performed by the electric motor M.

[0091] It is obvious from the above description that the hybrid powertrain of the vehicle according to the exemplary embodiment of the present invention can improve the shifting feel by eliminating torque interruption (torque interruption is a disadvantage of the automatic manual transmission (AMT)) by utilizing the motor while strengthening the advantages of the AMT, and eliminates the clutch between the motor and the engine required in the traditional hybrid powertrain (in which the motor is located between the engine and the transmission), thereby improving the installation convenience of the transmission in the vehicle due to reducing the overall length of the transmission, reducing the weight and production cost of the transmission, and helping to improve the fuel efficiency of the vehicle.

[0092] For ease of explanation and precise definition in the appended claims, the terms "upper," "lower," "inner," "outer," "above," "below," "upward," "downward," "front," "back," "backside," "inner," "outer," "inner," "exterior," "inner," "exterior," "inner side," "outer side," "forward," and "rearward" are used to describe features of the exemplary embodiments with reference to the positions of such features as shown in the accompanying drawings. It should be further understood that the term "connect" or its derivatives refers to both direct and indirect connections.

[0093] Furthermore, the term "fixedly connected" means that the fixedly connected members always rotate at the same speed. Furthermore, the term "selectively connectable" means that "the selectively connectable members rotate separately when the selectively connectable members are not engaged with each other, rotate at the same speed when the selectively connectable members are engaged with each other, and are stationary when at least one selectively connectable member is a stationary member and the remaining selectively connectable members are engaged with the stationary member."

[0094] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. The foregoing descriptions are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described in order to explain the specific principles of the invention and its practical application, thereby enabling others skilled in the art to realize and utilize the various exemplary embodiments of the invention and their various alternative forms and modifications. The scope of the invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A powertrain for a vehicle, comprising: an engine input shaft selectively connectable to the engine via a master clutch; a motor input shaft mounted coaxially with the engine input shaft and coupled to the motor; a central synchronizer mounted to selectively connect the engine input shaft to the motor input shaft; a first output shaft and a second output shaft, both mounted parallel to the engine input shaft; a variable drive gear mounted on the motor input shaft to maintain or increase the rotational speed of the motor input shaft and then transmit the maintained or increased rotational speed to the first output shaft; as well as a plurality of gear pairs mounted to establish different transmission gear ratios between the engine input shaft and the first output shaft and between the engine input shaft and the second output shaft; wherein the plurality of transmission ratios formed by the plurality of gear pairs and the two transmission ratios formed when the variable drive gear transmits power to the first output shaft form a series of different transmission ratios for driving the vehicle; The engine input shaft is provided with a driving gear, and the driving gear is integrally provided with a first clutch gear; The variable drive gear is integrally provided with a second clutch gear and is configured to be locked on the motor input shaft via a central synchronizer; The central synchronizer comprises: a hub fixed to the motor input shaft; and a sleeve mounted to be slidable on the hub in the axial direction of the motor input shaft and configured such that: when the sleeve moves to a first side of the hub, the sleeve engages with the first clutch gear to fixedly connect the hub to the engine input shaft; and when the sleeve moves to a second side of the hub, the sleeve engages with the second clutch gear to fixedly connect the hub to the variable drive gear.

2. The powertrain of a vehicle according to claim 1, wherein: The variable drive gear is mounted on the motor input shaft via a one-way clutch, and the one-way clutch is configured to transmit power in a direction from the motor input shaft to the variable drive gear; The variable drive gear is connected to a third rotation element of a first planetary gear set that further includes a first rotation element installed to be selectively fixed to a transmission case by a brake and a second rotation element connected to an input shaft of a motor.

3. The powertrain of a vehicle according to claim 2, wherein: The first rotation element, the second rotation element, and the third rotation element of the first planetary gear set are a sun gear, a planet carrier, and a ring gear, respectively.

4. The powertrain of a vehicle according to claim 1, wherein: The central synchronizer is connected to the engine input shaft in the form of a synchronizer device configured to perform synchronization interaction using synchronizer rings; The central synchronizer is connected to the variable drive gear in the form of a dog clutch.

5. The powertrain of a vehicle according to claim 1, wherein: the plurality of gear pairs including a first plurality of gear pairs and a second plurality of gear pairs; The first plurality of gear pairs between the engine input shaft and the first output shaft are mounted to achieve a second gear transmission ratio and a sixth gear transmission ratio among the different transmission ratios; The second plurality of gear pairs between the engine input shaft and the second output shaft are mounted to achieve a first gear transmission ratio and a fourth gear transmission ratio among the different transmission ratios; The variable drive gear is installed to transmit power to the first output shaft at a transmission ratio of a third gear and a transmission ratio of a fifth gear among different transmission ratios.

6. The powertrain of a vehicle according to claim 5, wherein: the first and second pluralities of gear pairs collectively comprising a first drive gear and a second drive gear; The first drive gear and the second drive gear are fixedly mounted on the engine input shaft, the first drive gear being commonly used to achieve the transmission ratio of the first gear and the transmission ratio of the second gear, and the second drive gear being commonly used to achieve the transmission ratio of the fourth gear and the transmission ratio of the sixth gear; The first plurality of gear pairs include: a first driven gear for a second gear position and meshing with the first drive gear, and a second driven gear for a sixth gear position and meshing with the second drive gear, the first driven gear and the second driven gear being rotatably mounted on the first output shaft; The second plurality of gear pairs includes a third driven gear for a first gear position meshing with the first drive gear and a fourth driven gear for a fourth gear position meshing with the second drive gear, the third and fourth driven gears being rotatably mounted on the second output shaft.

7. The powertrain of a vehicle according to claim 6, wherein: The first drive gear and the second drive gear are fixedly mounted on the engine input shaft so that the rotation of the first drive gear and the rotation of the second drive gear are locked to the engine input shaft; second and sixth gear synchronizing devices mounted on the first output shaft, the second and sixth gear synchronizing devices configured to selectively lock rotation of the first driven gear for the second gear and rotation of the second driven gear for the sixth gear on the first output shaft; First and fourth gear synchronizers are mounted on the second output shaft, and are configured to selectively lock rotation of the third driven gear for the first gear and rotation of the fourth driven gear for the fourth gear on the second output shaft.

8. The powertrain of a vehicle according to claim 6, wherein: A clutch gear configured to form a portion of a central synchronizer is integrally mounted on the second drive gear.

9. The powertrain of a vehicle according to claim 8, wherein: The clutch gear includes: the first clutch gear connected to the second drive gear; and The second clutch gear is connected to the variable drive gear.

10. The powertrain of a vehicle according to claim 1, wherein: A first output gear is fixed to the first output shaft; A second output gear is fixed to the second output shaft; The first output gear and the second output gear are commonly engaged with a ring gear of the differential device.

11. The powertrain of a vehicle according to claim 1, wherein: a motor driven gear configured to receive power from the motor fixed to the motor input shaft; A motor drive gear fixed to a rotating shaft of the motor meshes with the motor driven gear.

12. The powertrain of a vehicle according to claim 1, wherein: The rotating shaft of the motor is fixedly connected to the motor input shaft.

13. The powertrain of a vehicle according to claim 1, wherein: The motor input shaft is connected to the motor through a second planetary gear set, and the second planetary gear set is used to reduce the rotation speed of the motor and then transmit the reduced rotation speed to the motor input shaft.

14. The powertrain of a vehicle according to claim 13, wherein: The second planetary gear set includes a first rotation element, a second rotation element, and a third rotation element; The first rotating element is connected to a motor shaft of a motor, the second rotating element is connected to an input shaft of the motor, and the third rotating element is connected to a transmission case.

15. The powertrain of a vehicle according to claim 14, wherein: The first rotation element, the second rotation element, and the third rotation element of the second planetary gear set are a sun gear, a planet carrier, and a ring gear, respectively.

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