Power transmission device for four-wheel drive vehicle

Abstract

The present application provides a kind of power transmission device of four-wheel drive vehicle, which shortens front propeller shaft length to inhibit the deterioration of vibration characteristics, the reduction of maximum vehicle speed value.In the power transmission device (18) that distributes the torque transmitted to input shaft (42) to first output shaft (44) connected with rear propeller shaft (26) and second output shaft (50) connected with front propeller shaft (24) by differential mechanism (60), the power transmission path between differential mechanism (60) and second output shaft is provided with transmission mechanism (46) (or transmission mechanism (74)) which is arranged on axis (C4) and extends to the front of vehicle (10) from first transmission gear (46a) (or second sprocket (74a)).Therefore, the second opening part (56) for the second output shaft to pass through the housing of power transmission device is arranged in the front of vehicle, so the length of front propeller shaft is shortened, and the deterioration of vibration characteristics and the reduction of maximum vehicle speed value are inhibited.

Description

Technical Field

[0001] This invention relates to a power transmission device for a four-wheel drive vehicle that distributes and transmits torque from a drive source to the front and rear wheels. Background Technology

[0002] In four-wheel drive vehicles based on a front-engine, rear-wheel drive (FR) configuration, power transmission devices are known to distribute and transmit torque from the drive source to the front and rear wheels. For example, the power transmission device described in Patent Document 1 is such a device. In the four-wheel drive vehicle described in Patent Document 1, torque is transmitted from the first output shaft of the power transmission device to the rear wheels via the rear drive shaft, and from the second output shaft to the front wheels via the front drive shaft. However, it is known that if the drive shaft becomes longer, the resonant frequency of the drive shaft decreases, making it prone to resonance with the vehicle body and its various components, thus deteriorating vibration characteristics. As a countermeasure, Patent Document 2 discloses a technique for shortening the span of the drive shaft support portion.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-123683

[0004] Patent Document 2: Japanese Patent Application Publication No. 2006-103500

[0005] In the power transmission system of the four-wheel drive vehicle described above, the outlet of the second output shaft in the housing of the power transmission system is located at the rear of the vehicle. Therefore, the length of the front drive shaft used to connect to the front wheels is increased. As a result, the resonant frequency of the front drive shaft decreases, the vibration characteristics deteriorate, and the maximum vehicle speed may also decrease. Summary of the Invention

[0006] The present invention was made against the background of the above situation, and its purpose is to provide a power transmission device for a four-wheel drive vehicle that can shorten the length of the front drive shaft to suppress the deterioration of vibration characteristics and the reduction of the maximum vehicle speed.

[0007] The subject of the first invention is a power transmission device for a four-wheel drive vehicle, (a) comprising: an input shaft for transmitting torque from a drive source; a power distribution mechanism for distributing the torque to a first output shaft and a second output shaft; a rear drive shaft connected to the first output shaft; a front drive shaft connected to the second output shaft; and a housing for housing the input shaft, the first output shaft, the second output shaft, and the power distribution mechanism, wherein the input shaft, the first output shaft, the second output shaft, the rear drive shaft, and the front drive shaft are respectively arranged with their axes along the longitudinal direction of the vehicle, and the housing comprises: an input opening. The first opening is provided for the input shaft to pass through and is located on the front side of the vehicle of the housing; the second opening is provided for the second output shaft to pass through and is located on the front side of the vehicle of the housing, and is different from the input opening, wherein (b) the power transmission path between the power distribution mechanism and the second output shaft is provided with a transmission mechanism, which is located on an axis parallel to the power distribution mechanism and the second output shaft, and extends forward of the vehicle from the power transmission position of the power distribution mechanism.

[0008] According to the power transmission device for a four-wheel drive vehicle of the first invention described above, a transmission mechanism is provided in the power transmission path between the power distribution mechanism and the second output shaft. The transmission mechanism is located on an axis parallel to the power distribution mechanism and the second output shaft, and extends forward of the vehicle from the power transmission position with the power distribution mechanism. Therefore, the second opening is located at the front of the vehicle, thereby shortening the length of the front drive shaft and suppressing the deterioration of frequency characteristics and the reduction of the maximum vehicle speed. Attached Figure Description

[0009] Figure 1 This is a diagram illustrating a simplified example of the configuration of a four-wheel drive vehicle to which the present invention is applied.

[0010] Figure 2 Yes Figure 1 A schematic diagram illustrating the structure of the power transmission device.

[0011] Figure 3 Yes Figure 2 A schematic diagram illustrating a modified example of the power transmission device.

[0012] Figure 4 Yes Figure 1 A schematic diagram illustrating another embodiment of the power transmission device.

[0013] Figure 5 Yes Figure 1A schematic diagram illustrating another embodiment of the power transmission device.

[0014] Figure 6 This is a schematic diagram illustrating a comparative example of the existing configuration of a power transmission device. Explanation of reference numerals in the attached figures

[0015] 10…Vehicle (four-wheel drive vehicle); 12…Engine (drive source); 18…Power transmission device; 24…Front drive shaft; 24c…Intermediate section; 26…Rear drive shaft; 40…Housing; 42…Input shaft; 44…First output shaft; 46…Transmission mechanism; 46a…First transmission gear (power transmission position with power distribution mechanism); 50…Second output shaft; 52…Input opening; 54…First opening; 56…Second opening; 60…Differential mechanism (power distribution mechanism); 74…Transmission mechanism; 74a…Second sprocket (power transmission position with power distribution mechanism); 82…Front disconnect contact (power... Force distribution mechanism); 100… Bearing (support component); C1… Axis (axis of the first output shaft); C2… Axis (axis of the first output shaft); C2… Axis (axis of the second output shaft); C3… Axis (axis parallel to the first output shaft); C4… Axis (axis parallel to the power distribution mechanism and the second output shaft); C5… Axis (axis parallel to the first output shaft); CA… Gear carrier (second rotating element); MG… Motor; R… Ring gear (second rotating element); RE1… First rotating element; RE2… Second rotating element; RE3… Third rotating element; S… Sun gear (first rotating element). Detailed Implementation

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, in the following embodiments, the drawings have been appropriately simplified or modified, and may not accurately depict the dimensional proportions and shapes of the various parts.

[0017] [Example 1]

[0018] Figure 1 This diagram illustrates a simplified configuration of a four-wheel drive vehicle (hereinafter referred to as "vehicle") 10 to which the present invention is applied. The vehicle 10 includes an engine 12 as a drive source, a transmission 20 connected to the engine 12, front wheels 14, rear wheels 16, and a power transmission device 18 that transmits power (hereinafter referred to as torque) from the transmission 20 to the front wheels 14 and rear wheels 16. The vehicle 10 is a four-wheel drive (4WD) vehicle based on a front-engine, rear-wheel drive (FR) configuration.

[0019] The power transmission device 18 includes a transfer case 22, a front drive shaft 24 connected to the transfer case 22, and a rear drive shaft 26. Furthermore, a front differential 28 and a front drive shaft 32 are sequentially connected from the front drive shaft 24, and a rear differential 30 and a rear drive shaft 34 are sequentially connected from the rear drive shaft 26. The transfer case 22 distributes the torque of the engine 12 to the front wheels 14 and the rear wheels 16.

[0020] Figure 2 This is a schematic diagram illustrating the configuration of the transfer case 22 in the power transmission device 18. Figure 2 (a) is a collinear diagram showing the configuration of the transfer case 22a as an embodiment of this example. Figure 2 (b) is a collinear diagram showing the relative rotational speeds of the rotating elements of the differential mechanism 60 of the transfer case 22a.

[0021] exist Figure 2 In (a), the transfer case 22a includes a housing 40 for housing components. The transfer case 22a includes an input shaft 42, a differential mechanism 60, and a first output shaft 44, all disposed within the housing 40 on a common axis C1. Furthermore, the transfer case 22a includes a transmission mechanism 46, a driven gear 48, a second output shaft 50, and a motor MG for torque distribution, described later. The motor MG is, for example, a so-called electric generator, specifically a three-phase synchronous motor. Axis C2 is the axis of rotation of the driven gear 48 and the second output shaft 50, which are parallel to axis C1 and connected in a manner that prevents relative rotation. Additionally, axis C3 is the axis of rotation of the motor MG, which is parallel to axis C1.

[0022] The housing 40 includes: an input opening 52 through which an input shaft 42 passes and is located at the front of the vehicle 10 of the housing 40; a first opening 54 through which a first output shaft 44 passes and is located at the rear of the vehicle 10 of the housing 40; and a second opening 56 through which a second output shaft 50 passes and is located at the front of the vehicle 10 of the housing 40, and is different from the input opening 52. The first output shaft 44 passes through the first opening 54 and is connected to the rear drive shaft 26 in a manner that prevents relative rotation about axis C1. The second output shaft 50 passes through the second opening 56 and is connected to the front drive shaft 24 in a manner that prevents relative rotation about axis C2.

[0023] The differential mechanism 60 is a differential mechanism having three rotating elements: a first rotating element RE1, a second rotating element RE2, and a third rotating element RE3. For example, it is a known single-pinion planetary gear device comprising a sun gear S, a planet carrier CA, a ring gear R, and multiple pinions P supported by the planet carrier CA for rotation and revolution. In the differential mechanism 60, the sun gear S corresponds to the first rotating element RE1, the planet carrier CA corresponds to the second rotating element RE2, and the ring gear R corresponds to the third rotating element RE3. The electric motor MG is connected to the sun gear S via three MG connecting gears 62, 64, and 66 in a power-transmitting manner. The planet carrier CA is connected to the second output shaft 50 via a front connecting gear 68, a transmission mechanism 46 (described later), and a driven gear 48 in a power-transmitting manner. The ring gear R is connected to the input shaft 42 and the first output shaft 44 in a manner that prevents relative rotation about axis C1.

[0024] Figure 2 (b) is a collinear diagram showing the relative rotational speeds of the rotating elements of the differential mechanism 60. Figure 2 In (b), the three vertical lines Y1, Y2, and Y3 corresponding to the three rotating elements of the differential mechanism 60 constituting the transfer case 22a represent the rotational speeds of the sun gear S corresponding to the first rotating element RE1, the planet carrier CA corresponding to the second rotating element RE2, and the gear ring R corresponding to the third rotating element RE3, respectively, starting from the left.

[0025] If using Figure 2 Using the collinear diagram of (b), in the differential mechanism 60, the first rotating element RE1 is connected to the motor MG in a way that allows power transmission. The second rotating element RE2 is connected to the second output shaft 50 (front drive shaft 24). The third rotating element RE3 is connected to the input shaft 42 and the first output shaft 44 (rear drive shaft 26). In the differential mechanism 60, the relationship between the rotational speeds of the first rotating element RE1, the second rotating element RE2, and the third rotating element RE3 is represented by the straight line Lcd. The first output shaft 44 is the output shaft that outputs power to the rear wheel 16, and the second output shaft 50 is the output shaft that outputs power to the front wheel 14.

[0026] The differential mechanism 60 distributes the torque input to the third rotating element RE3 from the transmission 20 (engine 12 as the drive source) to the second rotating element RE2. That is, the differential mechanism 60 is equivalent to the "power distribution mechanism" of the present invention. Through the operation of the differential mechanism 60, torque distribution is performed between the front wheel 14 (second output shaft 50) and the rear wheel 16 (first output shaft 44) in the transfer case 22a. The differential mechanism 60 distributes torque to the front wheel 14 (second output shaft 50) and the rear wheel 16 (first output shaft 44) in any desired ratio corresponding to the reaction torque by utilizing the reaction torque of the electric motor MG, which bears the torque transmitted to the ring gear R on the sun gear S. The reaction torque of the electric motor MG is controlled, for example, by an electronic control device (not shown) that controls the vehicle 10, in which the electric motor MG performs power operation control during torque distribution. By controlling the reaction torque of the electric motor MG, the torque distribution ratio between the front wheel 14 (second output shaft 50) and the rear wheel 16 (first output shaft 44) can be arbitrarily changed.

[0027] The transmission mechanism 46 includes: a first transmission gear 46a located on an axis C4 parallel to axes C1 and C2, and meshing with a front connecting gear 68; a second transmission gear 46b meshing with a driven gear 48; and a transmission shaft 46c extending from the first transmission gear 46a toward the front of the vehicle 10, connecting the first transmission gear 46a and the second transmission gear 46b in a manner that prevents relative rotation about axis C4. That is, the transmission mechanism 46 extends from the first transmission gear 46a toward the front of the vehicle 10. The planetary carrier CA is connected to the front connecting gear 68 in a manner that prevents relative rotation, therefore the torque allocated to the planetary carrier CA corresponding to the second rotating element RE2 is transmitted to the second output shaft 50 via the front connecting gear 68, the transmission mechanism 46, and the driven gear 48. Axis C4 corresponds to the "axis parallel to the power distribution mechanism and the second output shaft" of the present invention, and the first transmission gear 46a corresponds to the "power transmission position with the power distribution mechanism" of the present invention.

[0028] In the transfer case 22a, torque is transmitted between the planetary gear carrier CA and the second output shaft 50 via the transmission mechanism 46, thereby enabling the second opening 56 to be positioned in front of the vehicle 10, for example, in the direction of axis C2, at the same position as or near the input opening 52. Figure 2 In (a), the second opening 56 is positioned in the direction of axis C2, further forward of the vehicle 10 than the input opening 52. This shortens the length of the front drive shaft 24.

[0029] Figure 3 This is a schematic diagram illustrating a modified example of the configuration of the transfer case 22a. Regarding the above... Figure 2Common parts are labeled with the same reference numerals and their descriptions are omitted.

[0030] Figure 3 (a) is in Figure 2 The example in (a) of the transfer case 22a changes the torque transmission between the planetary carrier CA corresponding to the second rotating element RE2 and the second output shaft 50 from gear-based meshing to chain-based connection. For example... Figure 3 As shown in (a), the torque allocated to the planetary carrier CA is transmitted to the second output shaft 50 via a first sprocket 70, chain 72, transmission mechanism 74, chain 76, and a fourth sprocket 78 connected to the second output shaft 50 in a manner that prevents relative rotation about axis C1. The transmission mechanism 74 includes: a second sprocket 74a connected to chain 72; a third sprocket 74b connected to chain 76; and a drive shaft 74c extending from the second sprocket 74a towards the front of the vehicle 10, connecting the second sprocket 74a and the third sprocket 74b in a manner that prevents relative rotation about axis (C4). That is, the transmission mechanism 74 extends from the second sprocket 74a towards the front of the vehicle 10. Thus, the connection within the transfer case 22a can also be appropriately selected using a gear or chain connection or other suitable method. Figure 3 In (a), it is also related to Figure 2 In (a) the same way, torque is transmitted between the planetary carrier CA and the second output shaft 50 via the transmission mechanism 74, thereby allowing the second opening 56 to be positioned in front of the vehicle 10, for example, in the direction of axis C2, at the same position as or near the front of the input opening 52. This shortens the length of the front drive shaft 24. Similar to the first transmission gear 46a in the transmission mechanism 46, the second sprocket 74a corresponds to the "power transmission position with the power distribution mechanism" of the present invention.

[0031] Figure 3 of (b) Figure 3 (c) Figure 3 (d) is in Figure 2 Example of changing the configuration of the motor MG in transfer case 22a of (a). Figure 3 of (b) Figure 3 (c) is an example of configuring the electric motor MG on the axis C1. Figure 3 (b) represents an example in which the electric motor MG is positioned behind the differential mechanism 60. Figure 3 (c) indicates an example where the electric motor MG is positioned in front of the differential mechanism 60. Additionally, Figure 3 (d) represents an example where the motor MG is positioned on axis C5, which is parallel to axis C1 and opposite to axis C3 relative to axis C1. In such cases... Figure 3 of (b) Figure 3When the electric motor MG is positioned on axis C1 as shown in (c), the body shape of the transfer case 22a in the vehicle width direction can be suppressed. Additionally, as... Figure 3 (d) of the above Figure 2 As in (a), when the electric motor MG is positioned on an axis parallel to axis C1, the longitudinal shape of the transfer case 22a in the vehicle 10 can be suppressed. Furthermore, by selecting axes C3, C5, etc., the balance of the vehicle width shape can be altered. Axis C3 and C5 correspond to the "axis parallel to the first output shaft" of this invention. Thus, by changing the configuration of the electric motor MG, the shape of the transfer case 22a can be changed, thereby flexibly addressing the layout requirements of the vehicle 10. Additionally, by simultaneously... Figure 2 In the same manner as in case (a), torque is transmitted between the planetary carrier CA and the second output shaft 50 via the transmission mechanism 46, allowing the second opening 56 to be positioned at the front of the vehicle 10, for example, in the direction of axis C2, at the same or forward position as the input opening 52. This shortens the length of the front drive shaft 24.

[0032] Figure 6 This is a schematic diagram illustrating a comparative example of a conventional configuration compared to the transfer case 22a of this embodiment. Figure 6 (a) indicates that Figure 2 The transfer case 22a of (a) is used as a comparative example of the existing transfer case 36a. Figure 6 (b) indicates that Figure 3 Transfer case 22a (c) is used as a comparative example of the existing transfer case 36b. Neither transfer case 36a nor transfer case 36b has a transmission mechanism 46; the front connecting gear 68 is directly connected to the driven gear 48. Therefore, as... Figure 6 (a) and Figure 6 As shown in (b), the second opening 56 is positioned further rearward than the input opening 52 of the vehicle 10. As a result, in the comparative example, the increased length of the front driveshaft 24 leads to deteriorated vibration characteristics and a potential decrease in the maximum vehicle speed; however, in this embodiment, the transfer case 22a ( Figure 2 (a) and Figure 3 In this process, the length of the front drive shaft 24 is shortened, thereby suppressing the deterioration of vibration characteristics and the reduction of the maximum vehicle speed.

[0033] As described above, according to this embodiment, the power transmission path between the differential mechanism 60 and the second output shaft 50 includes a transmission mechanism 46 (or transmission mechanism 74), which is located on axis C4 and extends from the first transmission gear 46a (or the second sprocket 74a) towards the front of the vehicle 10. Thus, the second opening 56 is located at the front of the vehicle 10, thereby shortening the length of the front drive shaft 24 and suppressing the deterioration of vibration characteristics and the reduction of the maximum vehicle speed.

[0034] Furthermore, according to this embodiment, the second opening 56 is provided in the direction of axis C2 at the same position as the input opening 52 or at the front of the vehicle 10. This allows the effects described above to be achieved.

[0035] Furthermore, according to this embodiment, the power transmission device 18 includes an electric motor MG, and the power distribution mechanism includes a differential mechanism 60. This differential mechanism 60 has three rotating elements: a first rotating element RE1, a second rotating element RE2, and a third rotating element RE3. The electric motor MG is connected to the first rotating element RE1, the transmission mechanism 46 (or transmission mechanism 74) is connected to the second rotating element RE2, and the first output shaft 44 is connected to the third rotating element RE3. Thus, the torque distribution ratio between the front wheel 14 and the rear wheel 16 can be arbitrarily changed.

[0036] Furthermore, according to this embodiment, the electric motor MG is positioned on an axis that is the same as or parallel to the axis C1. Therefore, by changing the configuration of the electric motor MG, the shape of the transfer case 22a can be changed, thus allowing for flexible adaptation to the layout requirements of the vehicle 10.

[0037] Next, other embodiments of the present invention will be described. Furthermore, in the following description, the same reference numerals are used for parts common to the embodiments described above, and the descriptions are omitted.

[0038] [Example 2]

[0039] Figure 4 This is a schematic diagram illustrating the configuration of the transfer case 22b in the power transmission device 18, which is an embodiment of this invention.

[0040] exist Figure 4 In this configuration, the transfer case 22b includes an input shaft 42, a secondary transmission unit 80, a front cut-off connection unit 82, and a first output shaft 44, all disposed within the housing 40 on a common axis C1. Additionally, the transfer case 22b includes a transmission mechanism 46, a driven gear 48, and a second output shaft 50 within the housing 40.

[0041] Similar to Embodiment 1 described above, the housing 40 includes an input opening 52, a first opening 54, and a second opening 56. An input shaft 42 passes through the input opening 52 and is connected to the input section of the transmission 20. A first output shaft 44 passes through the first opening 54 and is connected to the rear drive shaft 26 in a manner that prevents relative rotation about axis C1. A second output shaft 50 passes through the second opening 56, which is different from the input opening 52, and is connected to the front drive shaft 24 in a manner that prevents relative rotation about axis C2.

[0042] The auxiliary transmission unit 80 is a secondary gearbox equipped with a known planetary gear mechanism and a meshing clutch, which changes the rotational speed of the input shaft 42 and transmits it to the first output shaft 44. The speed change is performed, for example, by controlling an electronic control device that controls the vehicle 10 based on the driver's operation. Alternatively, an electric motor or similar device can be provided as a second drive source instead of the auxiliary transmission unit 80.

[0043] The front cut-off connection part 82 includes a front connecting gear 84 that is rotatable relative to the first output shaft 44, a locking gear 86 that is connected to the front connecting gear 84 in a non-rotatable manner, a drive gear 88 that is non-rotatable relative to the first output shaft 44, and a cut-off connection sleeve 90.

[0044] The front cut-off connection 82 switches the cut-off connection between the front connecting gear 84 and the drive gear 88. The inner circumferential teeth 90a of the cylindrical cut-off connection sleeve 90, which is positioned relative to the drive gear 88 in a manner that prevents relative rotation around the axis C1, engage with the locking gear 86 by moving in the direction of the axis C1. As a result, the front connecting gear 84 and the drive gear 88 are engaged, and the front connecting gear 84 and the drive gear 88 rotate as a unit.

[0045] The front connecting gear 84 is connected to the driven gear 48 via a transmission mechanism 46 disposed on the axis C4. The driven gear 48 is connected to the second output shaft 50 in a manner that prevents relative rotation about the axis C2. That is, the front connecting gear 84 and the second output shaft 50 (front drive shaft 24) are connected in a manner that enables power transmission.

[0046] Regarding the torque transmitted from engine 12 via transmission 20, in the released state of the front disconnector 82, the power transmission path between the first output shaft 44 and the front connecting gear 84 is cut off, and the torque is transmitted only to the first output shaft (rear drive shaft 26), that is, only to the rear wheel 16. In the engaged state of the front disconnector 82 (shown on paper), the torque is transmitted to the second output shaft 50 (front drive shaft 24) and the first output shaft (rear drive shaft 26), that is, to the front wheel 14 and the rear wheel 16, respectively. In other words, the front disconnector 82 is equivalent to the "power distribution mechanism" of the present invention. The switching between the released and engaged states of the front disconnector 82 is performed, for example, by controlling an electronic control device of the vehicle 10 based on the driver's operation.

[0047] In the transfer case 22b of this embodiment, the connection between the front connecting gear 84 and the driven gear 48 is also made via the transmission mechanism 46, thereby enabling the second opening 56 to be positioned in front of the vehicle 10, for example, in the direction of axis C2, at the same position as or near the front of the input opening 52. Figure 4 In the direction of axis C2, the second opening 56 is provided at the same position as the input opening 52. This shortens the length of the front drive shaft 24.

[0048] As described above, according to this embodiment, the power transmission path between the front cut-off connection 82 and the second output shaft 50 includes a transmission mechanism 46, which is located on axis C4 and extends from the first transmission gear 46a toward the front of the vehicle 10. Thus, the second opening 56 is located at the front of the vehicle 10, thereby shortening the length of the front drive shaft 24 and suppressing the deterioration of vibration characteristics and the reduction of the maximum vehicle speed.

[0049] Furthermore, according to this embodiment, the second opening 56 is provided in the direction of axis C2 at the same position as the input opening 52 or at the front of the vehicle 10. This allows the effects described above to be achieved.

[0050] [Example 3]

[0051] Figure 5This is a schematic diagram illustrating the configuration when the front driveshaft 24 is divided in the power transmission device 18. The front driveshaft 24 is configured such that, in a middle portion 24c located near the center along the C2 direction of the front driveshaft 24, it is divided into a first driveshaft 24a connected to the second output shaft 50 of the transfer case 22a and a second driveshaft 24b connected to the front differential 28. The first driveshaft 24a and the second driveshaft 24b are connected in the middle portion 24c in a manner that prevents relative rotation, for example, by spline engagement. Furthermore, the middle portion 24c is supported by a bearing 100 provided in the vehicle 10, allowing it to rotate. By configuring the front driveshaft 24 to be divided by the middle portion 24c and supported by the bearing 100 provided in the vehicle 10, allowing it to rotate, the length of the front driveshaft 24 is shortened, suppressing the deterioration of vibration characteristics and the reduction of the maximum vehicle speed. The bearing 100 corresponds to the "support member" of this invention. In this embodiment, it is the transfer case 22a, but it could also be the transfer case 22b as in Embodiment 2.

[0052] As described above, according to this embodiment, the front driveshaft 24 is configured such that a middle portion 24c is divided near the center in the direction of the axis C2 of the front driveshaft 24, and the middle portion 24c is supported by a bearing 100 of the vehicle 10 so that it can rotate. This shortens the length of the front driveshaft 24, suppressing the deterioration of vibration characteristics and the reduction of the maximum vehicle speed.

[0053] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is also applicable to other methods.

[0054] For example, in Embodiments 1 to 3 described above, vehicle 10 is a vehicle driven by engine 12, but the present invention can also be applied to hybrid electric vehicles (HEVs) and electric vehicles (BEVs) that are powered by both an engine and an electric motor.

[0055] Furthermore, in the differential mechanism 60 of Embodiments 1 and 3 described above, the second rotating element RE2 can be either the planetary gear carrier CA or the ring gear R, and the third rotating element RE3 can be either the planetary gear carrier CA or the ring gear R. When the second rotating element RE2 is the ring gear R and the third rotating element RE3 is the planetary carrier CA, the ring gear R is connected to the second output shaft (front drive shaft 24), and the planetary carrier CA is connected to the input shaft 42 and the first output shaft 44 (rear drive shaft 26). In this case, the electric motor MG performs regenerative control in the torque distribution between the front wheel 14 and the rear wheel 16.

[0056] Furthermore, the above is merely one implementation method, and the present invention can be implemented in various ways with modifications and improvements based on the knowledge of those skilled in the art.

Claims

1. A power transmission device (18) for a four-wheel drive vehicle, comprising: an input shaft (42) for transmitting torque from a drive source (12); a power distribution mechanism (60; 82) for distributing the torque to a first output shaft (44) and a second output shaft (50); a rear drive shaft (26) connected to the first output shaft; a front drive shaft (24) connected to the second output shaft; and a housing (40) for housing the input shaft, the first output shaft, the second output shaft, and the power distribution mechanism, wherein the input shaft, the first output shaft, and the second output shaft are connected to the second output shaft; and a housing (40) for housing the input shaft, the first output shaft, the second output shaft, and the power distribution mechanism. The second output shaft, the rear drive shaft, and the front drive shaft are respectively arranged along the longitudinal direction of the vehicle with axes (C1, C2). The housing includes: an input opening (52) through which the input shaft passes and is located on the front side of the housing relative to the vehicle; a first opening (54) through which the first output shaft passes and is located on the rear side of the housing relative to the vehicle; and a second opening (56) through which the second output shaft passes and is located on the front side of the housing relative to the vehicle, and is different from the input opening. The housing is characterized in that... The power transmission path between the power distribution mechanism and the second output shaft includes a transmission mechanism (46), which is located on an axis parallel to the power distribution mechanism and the second output shaft and extends forward of the vehicle from the power transmission position with the power distribution mechanism.

2. The power transmission device for a four-wheel drive vehicle according to claim 1, characterized in that, The second opening is located in the direction of the axis (C2) of the second output shaft at the same position as the input opening or at the front of the vehicle.

3. The power transmission device for a four-wheel drive vehicle according to claim 1 or 2, characterized in that, The power transmission device includes an electric motor (MG). The power distribution mechanism includes a differential mechanism (60), which has three rotating elements: a first rotating element (RE1), a second rotating element (RE2), and a third rotating element (RE3). The first rotating element connects to the electric motor, the second rotating element connects to the transmission mechanism, and the third rotating element connects to the first output shaft.

4. The power transmission device for a four-wheel drive vehicle according to claim 3, characterized in that, The motor is positioned on the same or parallel axis as the first output shaft (C3; C1; C5).

5. The power transmission device for a four-wheel drive vehicle according to claim 1, characterized in that, The front drive shaft is formed as a structure (24a, 24b) that is divided in the middle near the center in the axial direction of the front drive shaft, and the middle portion is supported by a support member (24c) of the vehicle so that it can rotate.

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