JPH0345856Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a full-time four-wheel drive system with a center differential and a differential lock, and more particularly to one in which the torque distribution between the front and rear wheels is variable. As a four-wheel drive system, there is a direct connection type that directly connects the front and rear wheels,
Some models have a center differential device installed in the middle of the transmission system for the front and rear wheels. In the case of a direct-coupling 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 two-wheel drive and four-wheel drive by connecting and disconnecting a transfer clutch.

[Conventional technology]

Conventionally, in the above-mentioned four-wheel drive system, a bevel gear type is mainly used for the center differential device, making it possible to absorb the rotation difference 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.

As a prior art, there is Japanese Utility Model Application No. 61-150631.

[The problem that the idea aims 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]

In the present invention, a planetary gear type center differential device is provided in the transfer device at the rear of the transmission, and dog clutches are provided on both sides of the planetary gear type center differential device.

The transmission output shaft is configured to be transmitted to a ring gear of the center differential device through a gear or the like, and inputs the transmission power.

In addition, at the front of the center differential device, power is transmitted from the carrier and sun gear to the front wheels via a dog clutch, and at the rear of the center differential device, power is similarly transmitted from the carrier and sun gear to the rear wheels via a dog clutch. It is configured.

The two sets of dog clutches are used to transmit power from either the carrier or sun gear or to defrot the gear, and are engaged with one shift rail in a linear pattern in three positions, simultaneously configured to work.

[Effect]

Based on the above configuration, in the first position, the transmission power input to the ring gear of the center differential device is transmitted from the carrier to the front wheels and from the sun gear to the rear wheels. , a driving mode that emphasizes stability with a large torque distribution to the front wheels.

In the third position, power is transmitted in the opposite relationship to that described above, resulting in a driving mode that emphasizes maneuverability with a large torque distribution to the rear wheels.

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 with approximately equal torque distribution between the front and rear wheels and intermediate performance between the first and third positions described above. .

Therefore, according to the present invention, it is possible to arbitrarily switch between three types of driving modes emphasizing stability, maneuverability, and both by changing the torque distribution between the front and rear wheels.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

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, the transfer device 18 disposed at the rear of the transmission 4 is provided with a planetary gear type center differential device 19 and two sets of dog clutches 20 and 21 arranged before and after the planetary gear type center differential device 19.
A rear drive shaft 22 is taken out at the rear of 1. The center differential device 19, dog clutches 20, 21, and rear drive shaft 22 are
It is arranged coaxially on the extension line of the front drive shaft 14 and extends from the rear drive shaft 22 to the propeller shaft 2.
3. Transmission is configured to the rear wheel side via the rear differential device 24.

The center differential device 19 is of a double pinion planetary gear type, and has two pinions 19c and 19d between a sun gear 19a and a ring gear 19b.
These pinions 19c and 19d are supported by a carrier 19e, so that the sun gear 19a and ring gear 19b rotate in the same direction.
Here, a gear 25 integral with the transmission output shaft 5 is configured to be transmitted to a gear 27 formed on the outer periphery of the ring gear 19b via a rotatably supported counter shaft 26.

The dog clutch 20 has a sleeve 20a that moves in three positions, front and rear.
The engaging portion 20b is always engaged between the front drive shaft 14 and the carrier 19e, and the switching portion 20c is released at the third position between the carrier 19e and the sun gear 19a. Switching section 20
d are respectively configured.

The dog clutch 21 has the same structure as described above, and includes a sleeve 21a and a rear drive shaft 22.
It has an engaging portion 21b that is always engaged between the two. On the other hand, the switching section 21c between the carrier 19e and the first
position, and the switching part 2 between the sun gear 19a and the sun gear 19a.
1d is adapted to be released in the third 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 locked to both sleeves 20a and 20b. ing.

Next, the operation of the four-wheel drive device configured as described above will be explained.

First, when the vehicle is running, 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 output shaft 5 has four forward speeds and one reverse speed. The gear shifting power is output. This shifting power is transmitted to the center differential device 19 via the gear 25, counter shaft 26, and gear 27.
input to the ring gear 19b.

Therefore, the switching lever 28 is moved to the third position as shown in FIG.
When in the position, the shift rail 29 moves the sleeves 20a, 20b of the dog clutches 20, 21 rearward, and the dog clutch 20 moves the switching portion 20
c is released, 20d is engaged, and the sun gear 19a of the center differential device 19 is connected to the front drive shaft 14.
join to. In addition, in other meshing clutches 21,
The carrier 19e is coupled to the rear drive shaft 22 by engaging the switching portion 21c and releasing the switching portion 21d.

Therefore, the power input to the ring gear 19b of the center differential device 19 is transmitted to the rear wheels from the carrier 19e, which has a large diameter from the center, and from the sun gear 19a, which has a small diameter, to the front wheels. becomes. Here, if the diameters of sun gear 19a and pinions 19c and 19d are made equal, the torque of carrier 19e and sun gear 19a will be 4:1, so front wheel torque TF and rear wheel torque TR in this driving mode are TF< It becomes a TR, and its performance emphasizes maneuverability.

On the other hand, the switching lever 28 is shifted to the first position, and the sleeves 20a and 20 together with the shift rail 29 are
When 1a is moved forward, switching portion 20c of dog clutch 20 is engaged and 21d is released to couple carrier 19e to front drive shaft 14. Further, in the dog clutch 21, the switching portion 21d is engaged, and the switching portion 21c is released, thereby coupling the sun gear 19a to the rear drive shaft 22.

Therefore, in this position, the relationship is completely opposite to that described above, and the sun gear 1 is moved from the carrier 19e to the front wheel side.
Power is transmitted from 9a to the rear wheel side. Therefore, although it is a four-wheel drive vehicle with a center differential, front wheel torque TF and rear wheel torque TR are TF>TR, resulting in performance that emphasizes stability.

Furthermore, when the switching lever 28 is in the intermediate second position, the switching parts 20c and 20 of the dog clutches 20, 21 are
d, 21c, and 21d engage together to lock and integrate the center differential device 19, and directly connect the drive shafts 14, 22.

Therefore, in this driving mode, the front and rear wheels are directly connected.
It becomes wheel drive, and TF≒TR, resulting in the above-mentioned intermediate performance.

Note that the actual gear structure of the center differential device 19 is as shown in FIG. 3, for example. In the figure, the same parts as in FIG. 2 are given the same reference numerals.

[Effect of idea]

As described above, according to the present invention, it is possible to arbitrarily select and obtain three types of driving modes: drivability-oriented, stability-oriented, and intermediate torque distribution.
It can demonstrate performance appropriate to the purpose and situation. Furthermore, the two sets of dog clutches have substantially the same structure and are symmetrically installed before and after the center differential device, which is advantageous in manufacturing and assembly. Furthermore, since two sets of dog clutches are operated by one shift rail, the operating system is simplified.

[Brief explanation of the drawing]

FIG. 1 is a skeleton diagram showing an embodiment of the four-wheel drive device of the present invention, FIG. 2 is a side view of a planetary gear type center differential device, and FIG. 3 is a side view of another embodiment. 4...Transmission, 5...Output shaft, 18...Transfer device, 19...Center differential device, 19a
...Sun gear, 19b...Ring gear, 19e...
...Carrier, 20, 21...Matching clutch, 2
0b, 21b...Engaging portion, 20c, 20d, 21
c, 21d...Switching section.

Claims (1)

[Scope of Claim for Utility Model Registration] A planetary gear type center differential device and two sets of dog clutches on the front and rear wheels are provided in the transfer device at the rear of the transmission, and the transmission output shaft is transmitted to the ring gear of the center differential device. Transmission is configured from the carrier and sun gear of the center differential device to the front wheels via the front wheel side meshing clutch, and transmission is configured to the rear wheel side via the rear wheel side meshing clutch, and two sets of meshing clutches are provided. The four-wheel vehicle is configured to transmit power from either the carrier or sun gear, or to defrot, and simultaneously operates the two sets of dog clutches to obtain three types of driving modes with different torque distribution between the front and rear wheels. Drive device.