JPH0345855Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a full-time four-wheel drive system equipped with a center differential and a differential lock, and more particularly to one in which torque distribution between the front and rear wheels is variable. As a four-wheel drive system, there are a direct connection type that directly connects the front and rear wheels, and a type that has a center differential device installed in the middle of the transmission system of the front and rear wheels. In the case of a direct drive type, it is not possible to absorb the difference in rotation between the front and rear wheels when turning, so it is necessary to switch between 2.4-wheel drive by connecting and disconnecting the transfer clutch.

2. Description of the Related Art Conventionally, in the four-wheel drive system described above, a bevel gear type is mainly used for the center differential, making it possible to absorb the difference in rotation between the front and rear wheels using a differential system. In addition, in the direct coupling type, a dog clutch is used as a transfer clutch.
The front and rear wheels are directly connected.

[Problem that the invention attempts to solve]

By the way, even if the bevel gear type differential device described above can absorb a rotation difference during turning, it cannot change the torque distribution between the front and rear wheels very much. Therefore, a direct-coupled or bevel gear type differential device with approximately equal torque distribution between the front and rear wheels can maintain relatively good stability, but it cannot be said to be sufficient in terms of maneuverability. The present invention was created with these points in mind, and it is possible to arbitrarily switch between torque distribution that emphasizes stability and maneuverability to achieve optimal power performance depending on the purpose or situation. The purpose is to provide a four-wheel drive device.

[Means to solve the problem]

The present invention includes a planetary gear type center differential device and two sets of dog clutches in the transfer device at the rear of the transmission. The output shaft of the transmission is connected to the carrier of the center differential device, and the transmission is configured to be transmitted to the front wheels via a first dog clutch having a switching section with a differential lock that selects either or both of the ring gear and sun gear. There is. Additionally, the second gear has a switching part for selecting either the ring gear or the sun gear of the center differential device.
Power is transmitted to the rear wheels via a dog clutch. The two sets of dog clutches are configured to engage one shift rail in a linear pattern of three positions and operate simultaneously.

[Effect]

Based on the above configuration, in the first position, the transmission power input to the carrier of the center differential device is transmitted from the ring gear to the front wheels and from the sun gear to the rear wheels. This is a driving mode that emphasizes stability. In the third position, power is transmitted in the opposite relationship to the above, with a center differential and a large rear wheel torque distribution.
This is a driving mode that emphasizes maneuverability. In the second position, the center differential device is locked and power is transmitted to the front and rear wheels, resulting in a driving mode in which the torque distribution between the front and rear wheels is approximately equal in a direct connection type, and the above-mentioned intermediate performance is achieved. Therefore, in the present invention, it is possible to arbitrarily switch between three types of driving modes that prioritize maneuverability, stability, and both by changing the torque distribution between the front and rear wheels.

【Example】

Embodiments of the present invention will be described with reference to the drawings. In the figure, an engine 1, a clutch 2, and a transmission 4 are arranged vertically in the longitudinal direction of the vehicle body, and a front differential device 1 is located at the bottom between the clutch 2 and the transmission 4.
6 is assembled and installed inside the transmission case to form a transaxle type. The above-mentioned transmission 4 is of a constant mesh type, and the output shaft 5 is connected to the input shaft 3.
are arranged parallel to each other, and four sets of transmission gears 6 to 9 meshing with each other, for example, first to fourth speeds, are provided on both shafts 3 and 5, and synchronization between gears 6 and 7 is provided. By selectively operating the mechanism 10 and the synchronizing mechanism 11 between the gears 8 and 9, each of the forward gears from the first speed to the fourth speed is obtained. Also, the reverse gear 1 provided on the input shaft 3
2, the gear 13 on the sleeve side of the synchronization mechanism 10 is engaged with the gear 13 via an idler gear (not shown) to obtain a reverse gear. The output shaft 5 is a hollow shaft, into which the front drive shaft 14 is inserted, and the drive pinion 15 disposed at the front end of the front drive shaft 14 is connected to the crown gear 1 of the front differential device 16.
7 and is configured to transmit power to the front wheel side. Further, in the transfer device 18 disposed at the rear of the transmission 4, a planetary gear type center differential device 19 and a dog clutch 20 are provided coaxially with the output shaft 5, and a rear drive shaft 21 is installed parallel to these. Another dog clutch 22 is provided. The rear drive shaft 21 is the propeller shaft 2.
3. Transmission is configured to the rear wheel side via the rear differential device 24. The planetary gear type center differential device 19 includes two sun gears 19a and 19b that rotate together, two pinions 19c and 19d, and one pinion 19.
Ring gear 19e meshing with d, both pinions 19
It consists of a carrier 19f supporting the carriers c and 19d.
The transmission output shaft 5 is connected to the carrier 19f. Also, one sun gear 19a has gear 2.
5 is integrally provided, and this gear 25 meshes with a gear 26 that is freely rotatable on the rear drive shaft 21. Furthermore, teeth are formed around the ring gear 19e, and mesh with a gear 27 that is rotatable on the rear drive shaft 21. The dog clutch 20 has a sleeve 20a that moves in three positions, front and rear.
A switching part 20b is disposed between the ring gear 19e and the ring gear 19e, and a switching part 20c is disposed between the sun gear 19b and the sun gear 19b, and the switching part 20c is always engaged with the front drive shaft 14. The engaging portions 20d are respectively configured to do this. The other dog clutch 22 has an engaging portion 22b that is always engaged between the sleeve 22a and the rear drive shaft 21, and a switching portion that is engaged only in the first position between the sleeve 22a and the gear 26. 22c is further provided with a switching portion 22d between the gear 27 and the switching portion 22d, which is opened in the opposite direction only in the first position. As an operating system, there is a switching lever 28 with a pattern in which three positions are linearly arranged in the front and back direction, and one shift rail 29 from this switching lever 28 is connected to the sleeve 20a of both dog clutches 20, 22. , 22a. Next, the operation of the four-wheel drive device configured as described above will be explained. First, when the vehicle is running, the power from the engine 1 is input to each gear of the transmission 4 via the clutch 2 and the input shaft 3, and by operating the synchronizing mechanisms 10, 11, etc., the power from the engine 1 is transmitted to the output shaft 5 by each gear. Shift power for 1st reverse gear is output. This shifting power is then input to the carrier 19f of the center differential device 19. Therefore, when the switching lever 28 is shifted from the intermediate second position to the first position as shown in the figure, and the shift rail 29 is moved forward, the sleeve 20a of the dog clutch 20 moves in the same manner, so that the switching portion 20c is released, and the switching part 20b and the engaging part 2
The ring gear 19e of the center differential device 19 is coupled to the front drive shaft 14 by engagement at 0d. Further, in other dog clutches 22, when the sleeves 22a move in the same manner, the switching portions 22c engage and the switching portions 22d are released, thereby shifting the gear 2 from the sun gear 19a of the center differential device 19
5 and 26 to the rear drive shaft 21. Therefore, the carrier 1 of the center differential device 19
The power input to 9f is transmitted to the front wheels from the ring gear 19e, which has a large diameter from the center, and from the sun gear 19a, which has a small diameter, to the rear wheels. It has four-wheel drive. In this driving mode, the front wheel torque TF and the rear wheel torque TR become TF>TR due to power transmission from the ring gear 19e and sun gear 19a, resulting in performance that emphasizes stability. On the other hand, when the switching lever 28 is shifted to the third position and the shift rail 29 is moved backward, the switching portion 20b of the dog clutch 20 is released and the switching portion 20c is engaged, and the center differential device 1
The sun gear 19b of No. 9 is coupled to the front drive shaft 14. In addition, in the other dog clutches 22, the switching portion 22c is released and the switching portion 22d is engaged, so that the ring gear 19e of the center differential device 19 is
is connected to the rear drive shaft 21 via a gear 27. Therefore, at this shift position, the relationship is completely opposite to that described above, and by transmitting power from the ring gear 19e of the center differential device 19 to the rear wheels and from the sun gear 19b to the front wheels, the front wheels respond to rotational fluctuations of the rear wheels. It is a four-wheel drive system with a center differential, which has a large influence on the vehicle. And in this driving mode, TF<
It becomes a TR, and its performance emphasizes maneuverability. Further, when the switching lever 28 is in the intermediate second position as shown in the figure, the switching parts 20b and 20c of the dog clutch 20 are engaged together, so that the center differential device 19 connects the sun gear 19b and the ring gear 19e. and is connected to the front drive shaft 14. In addition, meshing clutch 2
2 is in the same operating state as described above, and is connected to the rear drive shaft 21 from the ring gear 19e through the gear 27.
join to. Therefore, in this driving mode, the front and rear wheels are directly connected.
It becomes wheel drive, and TF≒TR or TF>TR, resulting in the above-mentioned intermediate performance. Although one embodiment of the present invention has been described above, the shift rail 29 can also be moved by a button switch using an actuator using electricity, negative pressure, or the like.

[Effect of the idea]

As described above, according to the present invention, it is possible to arbitrarily select and obtain three types of driving modes: one that emphasizes maneuverability, one that emphasizes stability, and an intermediate torque distribution. performance. Furthermore, since two sets of dog clutches are operated by one shift rail, the operating system is simplified. Furthermore, since the pattern has an intermediate shift position between shift positions that emphasize maneuverability and stability, operability is also good.

[Brief explanation of the drawing]

The drawing is a skeleton diagram showing an embodiment of the four-wheel drive device of the present invention. 4...Transmission, 5...Output shaft, 14...Front drive shaft, 19...Center differential device, 19
a, 19b... sun gear, 19c, 19d... pinion, 19e... ring gear, 19f... carrier, 20... dog clutch, 20b... switching section, 20c... switching section, 21... rear drive shaft, 22... meshing clutch, 22c, 22d...
...Switching section.

Claims (1)

[Claim for Utility Model Registration] In a transfer device at the rear of a transmission, the output side of the transmission is connected to a carrier of a planetary gear type center differential device, and one or both of a ring gear and a sun gear of the center differential device are selected. Transmission is configured to the front wheels through a first dog clutch that has a switching part with a differential lock to select between the ring gear and the sun gear of the center differential device, and a second dog clutch that has a switch part that selects either the ring gear or the sun gear of the center differential device. The transmission is configured to the rear wheel side, and the two sets of dog clutches mentioned above are operated at the same time.
A four-wheel drive system that provides three driving modes with different torque distribution between the front and rear wheels.