JPS63112222A - Torque distributing device for four-wheel drive car - Google Patents

Abstract

PURPOSE:To reduce the volume and the size of a device, by a method wherein a boosting means is situated in a torque transmission route running from a transmission to a switching mechanism which selectively brings center diffs or either of the center diffs into a torque transmission state. CONSTITUTION:Torque outputted from an engine through the medium of a transmission is inputted to a switching mechanism 70 through a torque distributing device 3. When a sleeve 74 of the switching mechanism 70 is slid, for example, leftward, the torque is inputted to a carrier 44 of a first center gear 40, and the torque divided to the sun gear 41 side is outputted to an intermediate shaft 23 or a first output gear 83 for front wheels. The torque divided to the ring gear 45 side is outputted to a first output gear 81 for rear wheels. In this case, after the torque divided to an intermediate shaft 23 or a first output gear 83 for front wheels is inputted to a sun gear 91 of a reduction mechanism 90 through a second output gear 84 for front wheels, the torque is divided to left and right front wheel drive shafts 21 and 22 by means of a front diff 30.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a four-wheel drive vehicle that drives front and rear wheels, particularly as a center differential that absorbs the difference in rotational speed between the front and rear wheels. The present invention relates to a torque distribution device for a four-wheel drive vehicle equipped with a plurality of center differentials with different torque distribution ratios to rear wheels.

(Prior Art) In four-wheel drive vehicles that drive the front and rear wheels by dividing the torque output from the engine through the transmission, a center differential is installed to eliminate the so-called braking phenomenon during cornering. may be provided. This center differential consists of an input element into which torque from the engine or transmission is input, and output elements for front wheels and rear wheels that divide the torque input into the element and transmit it to the front wheels and rear wheels, respectively, By performing differential operation between both output elements, the difference in rotational speed between the front and rear wheels during cornering is absorbed.

. By the way, as for the above differential, it is preferable to use a planetary gear VIa structure consisting of a sun gear, a plurality of pinion gears that mesh with the gears, a pinion carrier that supports these gears, and an internally toothed ring gear that meshes with each pinion gear. Although it is usual, for example, according to Japanese Patent Publication No. 61-62641 and Japanese Patent Application Laid-Open No. 61-94822, a plurality of planetary gear mechanisms having different gear diameters are arranged in parallel, and these are selectively used as a center differential. The configuration configured to do this is shown. According to this, the torque distribution ratio to the front and rear wheels differs depending on the center differential (planetary gear mechanism) selected to be used, resulting in optimal driving performance depending on, for example, road surface conditions and driver preference. .

(Problem to be Solved by the Invention) However, when a plurality of center differentials are provided as described above, a switching mechanism for selectively setting one of the center differentials to a torque transmitting state is additionally required. The torque distribution device for the drive vehicle has a large number of constituent members, which results in an increase in the size of the device.

The present invention deals with the above-mentioned situation when a plurality of center differentials and their switching mechanisms are provided, and by miniaturizing these as much as possible, the torque distribution device in this type of four-wheel drive vehicle is miniaturized. The purpose is to

(Means for Solving the Problems) That is, the torque distribution device for a four-wheel drive vehicle according to the present invention has a center differential that divides the torque input from the engine via the transmission and transmits the divided torque to the front wheels and rear wheels, respectively.
In addition to providing a plurality of center differentials that are responsible for the distribution ratio of torque output to the front wheels and torque output to the rear wheels, and a switching mechanism that selectively puts one of these in a torque transmission state, The present invention is characterized in that a speed increasing means is interposed in a torque transmission path from the output gear of the transmission to the switching mechanism and the center differential.

(Function) According to the above configuration, by selecting one of the plurality of center differentials by operating the switching mechanism, the torque distribution to the front and rear wheels can be biased toward the front wheels or the rear wheels, for example, or It is possible to switch to state 1, where the output is evenly distributed to the front and rear wheels, and the output from the transmission is input to the switching mechanism or center differential via the speed increasing means, so that the output from the transmission is input to the switching mechanism and each center differential. Since the input torque is reduced, it becomes possible to reduce the volume of these components, and accordingly, it becomes possible to use small-sized devices that occupy a small space as the switching mechanism and each center differential.

(Example) Examples of the present invention will be described below.

First, the overall configuration of the four-wheel drive vehicle according to this embodiment will be explained with reference to FIG. 1. In this four-wheel drive vehicle, an engine 1 and an engine 1 are installed at the front of the vehicle body. A power plant consisting of a transmission 2 and a torque distribution device 3 is installed. The engine 1 is arranged so that its output shaft 4 extends in the width direction of the vehicle body. In addition, transmission 2 also
An input shaft 6 connected to the engine output shaft 4 via a clutch 5 and an output shaft 7 parallel thereto are arranged to extend in the width direction of the vehicle body, and input and output shafts 6.7 of the transmission 2 are arranged to extend in the width direction of the vehicle body. In between, each gear train 81-8s, o
r, and an output gear 9 is provided at one end of the output shaft 7 for transmitting torque from the transmission 2 to the torque distribution device 3.

On the other hand, the torque distribution device 3
The input torque is divided and outputted to the left and right front wheels.
0.11 and a propeller shaft 12 that extends in the longitudinal direction of the vehicle body, a rear wheel differential device (hereinafter referred to as a reset differential) 1
3 and a rear wheel drive shaft 14 extending left and right from the V-differential 13.
．． 15, the left and right rear wheels 16 and 17 are driven.

Next, the internal structure of the torque distribution device 3 will be explained with reference to FIG. The shafts 21 and 22, an intermediate shaft 23 disposed parallel to these shafts, and a rear wheel output shaft 24 disposed in the longitudinal direction of the vehicle body and protruding tangentially are all rotatably supported. The left and right front wheel drive shafts 21.22 are connected to the front wheels 10.11 shown in FIG. 1, and the rear wheel output shaft 24 is connected to the propeller 11.
4112, respectively.

Further, a bevel gear type front wheel differential (hereinafter referred to as front differential) 30 is disposed around the opposing ends of the left and right front wheel drive shafts 21 and 22, and a bevel gear type front wheel differential (hereinafter referred to as front differential) 30 is arranged on the intermediate shaft 23. The first planetary gear type. 2nd center differential 4
0.50 is placed.

The front differential 30 has a boss portion 31 extending on both left and right sides.
', 31'' are rotatably fitted and supported on the left and right front wheel drive shafts 21, 22, and a pinion shaft installed in the case 31 in a direction perpendicular to the axis of the front wheel drive shafts 21, 22. 32, a pair of pinion gears 33 and 34 rotatably supported by the shaft 32,
It is composed of a pair of left and right output gears 35, 36 meshed with both pinion gears 33, 34, and the ends of left and right front wheel drive shafts 21, 22 are connected to both output gears 35, 36, respectively.

On the other hand, the first center differential 40 on the intermediate shaft 23 is composed of a single binion type planetary gear mechanism, and as shown in FIG. pinion gear 42...4
2, a carrier 44 that supports these pinion gears 42...42 via pinion shafts 43...43, and a ring gear 45 that is arranged on the outside of each pinion gear r42...42 and meshes with them. It is configured.

On the other hand, the second center differential 50 is composed of a double binion type planetary gear mechanism, and as shown in FIG. 52, and a plurality of second pinion gears meshing with these pinion gears 52...52, respectively.
The pinion gears 53...53 and the first. A carrier 56 that supports each second pinion gear 52...52°53...53 via a pinion shaft 54...54°55...55, and a second pinion gear 53...53.
A ring gear 57 is arranged on the outside of the ring gear 57 and meshes with the ring gear 57.

Further, as shown in FIG. 2, a large-diameter idle gear 61 is rotatably fitted and supported on the outside of the differential case 31 of the front differential 30, and is meshed with the output gears 9 of the above-mentioned lance transmissions 1 to 2. At the same time, the idle gear 61 is meshed with a small-diameter input gear 62 rotatably supported on the intermediate shaft 23.
and the input gear 62 constitute a speed increasing mechanism 60 that speeds up the output of the transmission 2 and transmits it onto the intermediate shaft 23. The input gear 62 and the first gear on the intermediate shaft 23 are connected to each other on the intermediate shaft 23. A switching mechanism 70 is provided between the second center differentials 40 and 50.

This switching mechanism 70 includes a first spline 71 integrally formed with the input gear 62, a second spline 72 integrally formed with the carrier 44 of the first center differential 40, and an extension member 57 of the ring gear 57 in the second center differential 50. ′
The third spline 73 is formed in the third spline 73, and a slidable sleeve 74 is fitted over these splines 71-73. When the sleeve 74 is slid to the left as shown in the figure, the first and second
Splines 71 and 72 are coupled to input gear 62 and the first
Once the carrier 44 of the center differential 40 is connected and the sleeve 74 is slid from the illustrated device to the right, the first.
The third spline 71.73 is coupled to the input gear 62.
and the ring gear 57 of the second center differential are connected.

On the other hand, the ring gear 45 of the first center differential 40 and the carrier 56 of the second center differential 50 are connected to each other, and a first bevel gear-shaped bullet wheel is rotatably supported on the intermediate shaft 23.
It is coupled to the output gear 81, and is meshed with a second output gear 82 for ring erosion, which is also in the form of a bevel gear and is provided at the end of the output shaft 24 for the rear wheels. Also, the sun gear 41. of the 1st degree 2nd t7 differential 40.50.
51 is integrally connected to the intermediate shaft 23, and a first output gear 83 for front wheels is integrally formed on the intermediate shaft 23. A second front wheel output gear 84 rotatably supported via a boss portion 31' is meshed with the front wheel. Furthermore,
On the post portion 1' of the differential case 31, there is a sun gear 9.
1 and a plurality of pinion gears 92...92 that mesh with this
and a carrier 9 that supports these pinion gears 92...92 via pinion shafts 93...93, respectively.
4 and a ring gear 95 that meshes with each pinion gear 92...92. The sun gear 91 in the reduction mechanism 90 and the second output gear 84 for front wheels are integrated, the ring gear 95 is fixed to the case 20 of the torque distribution device 3, and the carrier 94 is connected to the front differential 30. It is connected to the boss portion 31' of the differential case 31 at.

Incidentally, in this embodiment, in addition to the above configuration, the above-mentioned first. A viscous coupling 100 as differential limiting means for the second center differential 40, 50 and a differential lock mechanism 110 as differential blocking means are provided. The viscous coupling 100 is arranged between an outer case 101 coupled to the idle gear 61, an inner case 102 coupled to the differential case 31 of the front differential 30, and both cases 101 and 102, and alternately connects them. It has a large number of engaged plates 103...103,
In addition, the plates 103...103 are filled with viscous fluid. When the rotation speed difference between the outer case 101 (idle gear 61) and the inner case 102 (differential case 31) is small, relative rotation between them is allowed, but when the rotation speed difference exceeds a predetermined amount, viscous fluid The resistance acts to limit the relative rotation.

Further, the differential lock mechanism 110 is connected to the idle gear 6.
Splines 111 and 112 having the same specifications are provided adjacent to the extension part 61' of the differential case 1 and the boss part 31'' of the differential case 31, and a sleeve 113 is slidably fitted over these splines 111 and 112. It is said that
When the sleeve 113 is slid to the right from the illustrated position, the idle gear 61 and the differential case 31 of the front differential 30 are coupled together.

Next, to explain the operation of this embodiment, the power is output from the engine 1 via the transmission 2.

The torque is input from the output gear 9 of the transmission 2 to the switching device ta70 via the idle gear 61 in the torque distribution device 3 and the input gear 62 on the intermediate shaft 23. When the sleeve 74 in the switching mechanism 70 is slid to the left as shown in the figure, torque is input to the carrier 44 of the first center differential 40 and is divided between the sun gear 41 and the ring gear 45. The torque divided to the 41 side is transmitted to the intermediate shaft 23 or the first output gear 83 for the front wheels, and the torque divided to the ring gear 45 side is transmitted to the first output gear 81 for the rear wheels via the carrier 56 of the second center differential 50. Output. Further, when the sleeve 74 in the switching mechanism 70 is slid to the right, the torque is 21? Ring gear 5 of Nta differential 50
7, the torque is input to the sun gear 51 and the carrier 56, and similarly to the first center differential 40, the torque divided to the sun gear 51 side is transmitted to the intermediate shaft 23 or the first output gear 83 for the front wheels, and then to the carrier 56. The torque divided to the 56 side is output to the first output gear 81 for rear wheels, respectively. In any case, the torque output to the intermediate shaft 23 or the first output gear 83 for front wheels is input to the sun gear 91 of the reduction mechanism 90 via the second output gear 84 for front wheels. After being decelerated by the mechanism 90, the deceleration is transmitted from the carrier 94 to the differential case 31 of the front differential 30, and further divided by the front differential 30 into the left and right front wheel drive shafts 21,22, and the deceleration is transmitted to the left and right front wheels 10 degrees 11. are transmitted respectively. Further, the torque output to the first output gear 81 for the rear wheels is transmitted to the output shaft 24 for the rear wheels via the second output gear 82 for the rear wheels, and is further transmitted to the propeller shaft 12 and the rear differential 1.
3 and the left and right rear wheels 16.3 through the rear wheel drive shafts 14.15.
17.

In that case, when the torque is divided by the first center differential 40, the carrier 44 of the center differential 40
Since the torque input to the sun gear V41 and the ring gear 45 is distributed to, for example, 3-near according to the ratio of the number of teeth of both gears 41.45, the torque transmitted from the sun gear 41 to the front wheel 10.11 side is From ring gear 45 to rear wheel 16.
The torque transmitted to the 17 side becomes larger, resulting in a so-called torque distribution that is biased toward the rear wheels and is suitable for sporty driving. On the other hand, when the torque is distributed by the second center differential 50, if the ratio of the number of teeth between the sun gear 51 and the ring gear 57 is set to 1:2, for example, the torque input to the ring gear 57 is distributed between the sun gear 51 and the carrier 56. Toni 2
It will be divided equally, so the torque distribution will be the same as before. The rear wheels are evenly distributed and are suitable for normal driving or driving on rough roads.

Incidentally, the rotational speed is input from the transmission output gear 9 to the idle gear 61 after being reduced, and the rotational speed of the idle gear 61 is input to the front differential 3 on the same axis.
0 or left and right front wheel drive shafts 21.22, that is, front wheels 10
．． 11 (if there is no difference in rotational speed between the front and rear wheels), but from the idle gear 61 to the input gear 62 on the intermediate shaft 23, these gears 61.6
The rotational speed of the front differential 30 and the like is increased by the speed increasing mechanism 60 comprised of 2 and inputted. Therefore, the switching mechanism 70 on the intermediate shaft 23 and the first. The input torque to the second center differential 40.50 becomes smaller,
It becomes possible to reduce these capacities. Therefore,
The switching mechanism 70 and the first. As the second center differential 40, 50, a small one that occupies a small space can be used, and accordingly, the torque distribution device 3 can be made more compact. In addition, 1st. 2nd center differential 40.50
The increased output speed is transmitted to the front wheels after being decelerated by a deceleration mechanism 90, and is transmitted to the rear wheels after being decelerated by a V-differential 13 as shown in FIG.

Here, in the torque distribution device 3 according to this embodiment, when a rotational speed difference occurs between the front and rear wheels, that is, the first.
The second center differential 40.50 performs differential operation, and a rotational speed difference is generated between the idle gear 61 in the input path to these center differentials 40.50 and the differential case 31 of the front differential 30 in the front wheel side output path. If this occurs, and the rotational speed difference exceeds a predetermined value, the viscous coupling 100 acts to eliminate or suppress this.

Therefore, for example, when cornering sharply, the first. The differential operation of the center differential is controlled according to the driving condition, such as preventing instability of the driving condition due to excessive rotational speed difference between the front and rear wheels being allowed by the second center differential 40.50. It turns out. Further, for example, in a case where either the front or rear wheels slips and torque is no longer transmitted to the other, the idle gear 61 and the differential case 31 of the front differential 30 can be connected by the differential lock mechanism 110. ．． The differential operation of the second center differential 40°50 is completely blocked and torque is transmitted to both the front and rear wheels, making it possible to escape from a slip state.

Note that FIG. 5 shows another embodiment of the present invention, and the torque distribution device 3a according to this embodiment has a first... A second center differential 408.50a is disposed, and the switching mechanism 70a and the speed increase mechanism 60a are disposed on the left front wheel drive shaft 2''la, and the speed increase mechanism 60 includes a sun gear 61a and the gear 61a. A planetary gear mechanism is used, which includes a plurality of pinion gears 62a...62a that mesh with each other, a carrier 63a that supports these gears, and a ring gear 64a that meshes with each of the pinion gears 62a...62a. Input gear 65 meshing carrier 63a with transmission output gear 9a
a, the ring gear 64a is fixed, and the input rotation from the carrier 63a is accelerated and output to the sun gear 61a.

In this torque distribution device 3a, the speed increasing mechanism 9
The accelerated rotation from the sun gear 61a of No. 08 is input to the switching mechanism 70a, and the sleeve 74a of the switching mechanism 70a
Depending on the position of 1. 2nd output gear 838.84a
and the left and right front wheel drive shafts 21 via the front differential 30a.
a, 22a, and the output to the ring gear 45a of the first center differential 40a or the carrier 56a of the second center differential 50a is transmitted to the rear wheel cylinder 1. The power is transmitted to the rear wheel output shaft 24a via the second output gears 81a and 82a, respectively. Also in this torque distribution device 3a, the switching mechanism 70a
Since the inputs to the first and second center differentials 40a and 50a are increased in speed by the speed increasing mechanism 60a, their capacities and sizes can be reduced. Here, in this torque distribution device 3a, the first. 2nd center differential 40a
, 50a is interposed between the output path to the front wheel side and the output path to the rear wheel side.

In addition, in the above-mentioned second embodiment, since the switching mechanism and the plurality of center differentials are provided with a common speed increasing mechanism, the space occupied by the speed increasing mechanism can be minimized, and the torque distribution of 111 it can be made more compact. It will be done.

Effects of the Invention As described above, according to the present invention, in a four-wheel drive vehicle equipped with a plurality of center differentials with different torque distribution ratios to the front wheels and rear wheels, and a switching mechanism thereof, the above-mentioned switching can be performed from the transmission. Since the speed increasing means is provided in the torque transmission path to the switching mechanism or the center differential, the input torque to the switching mechanism or the center differential becomes smaller, and the capacity thereof can be reduced, that is, the size can be made smaller than the space required to install the speed increasing means. This makes it possible to make this type of torque distribution device more compact.

[Brief Description of the Drawings] Figures 1 to 4 show a first embodiment of the present invention, and Figure 1 is a schematic diagram showing the overall configuration of a four-wheel drive vehicle according to the embodiment.
FIG. 2 is a longitudinal cross-sectional view of the main part, and FIG. 3-4 is the first section of the embodiment. FIG. 2 is a schematic diagram showing the configuration of a second t-nt differential. Further, FIG. 5 is a schematic diagram of main parts showing another embodiment of the present invention. 1... Engine, 2... Transmission, 9°9a... Output gear, 40.40a... 1st center differential, 50.508... 2nd center differential, 70°70a
...Switching mechanism, 90.90a...Speed-up means.

Claims (1)

[Claims] (1) In a four-wheel drive vehicle equipped with a center differential that divides the torque input from the engine via the transmission and transmits it to the front wheels and the rear wheels, the center differential divides the torque output to the front wheels and the rear wheels. A plurality of center differentials having different distribution ratios of torque output to the sides are provided, and a switching mechanism is provided to selectively put one of these into a torque transmission state, and the output gear of the transmission is connected to the switching mechanism and the center differential. A torque distribution device for a four-wheel drive vehicle, characterized in that a speed increasing means is interposed in a torque transmission path.