JPH02109733A - Driving force distribution device for vehicle - Google Patents

Abstract

PURPOSE:To adjust driving force distribution ratio in an extended area by providing a clutch means capable of adjusting the transmitting torque of each output shaft, in a driving force distribution device with a differential mechanism in which first output shaft is connected to one driving wheels and the second output shaft is connected to the other driving wheels. CONSTITUTION:An output shaft 13 of a transmission 12 is connected to a center differential 19 with a differential mechanism 14 and a differential limit clutch 15 through a drive gear 13a integrated with the output shaft 13. Side gears 18a and 18b of the differential mechanisms 14 are connected to output shafts 20 extending forward and backward and passing through a case 16 rotatably. Output shafts 20F and 20R are connected to a front clutch 21F and a rear clutch 21R for driving force regulation comprizing a hydraulic multi-disk clutch. The clutches 21F and 21R are so constructed that the transmitting torque can be varied according to a press pressure by hydraulic actuators 26F and 26R controlled by a control unit 30 according to operating conditions of a vehicle.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a driving force distribution device for a vehicle.

(Prior Art) Conventionally, a driving force distribution device for a vehicle is disclosed in, for example, Japanese Unexamined Patent Publication No. 62-2
As described in Publication No. 03825, a speed increase mechanism and a hydraulic clutch are provided in series between two output shafts of a differential mechanism, and the torque transmitted by the hydraulic clutch is changed to increase the torque of one output shaft by the speed increase mechanism. It is known that the drive force is transmitted to the other output shaft to adjust the distribution of the driving force of the output shaft.

(Problem to be Solved by the Invention) However, in the driving force distribution device of the above-mentioned Japanese Patent Application Laid-Open No. 62-203825, a hydraulic clutch and a speed increasing mechanism must be assembled to the differential mechanism, As the drive mechanism becomes larger and the speed increasing mechanism transmits the torque of one output shaft to the other output shaft, the range in which the driving force distribution ratio can be adjusted is defined by the speed ratio of the speed increasing mechanism, etc. The range in which the force distribution ratio can be adjusted was also narrow.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a driving force distribution device that can adjust the driving force distribution ratio over a wide range without increasing the size.

(Means for Solving the Problems) This invention includes a differential mechanism in which an input shaft is connected to an engine, a first output shaft is connected to one drive wheel, and a second output shaft is connected to the other drive wheel. , a driving force distribution device for a vehicle in which the differential mechanism transmits engine power to each drive wheel while allowing a differential, comprising differential limiting means capable of limiting the differential of the differential mechanism; a first clutch means capable of adjusting the transmission torque of the output shaft; a second clutch means capable of adjusting the transmission torque of the second output shaft;
The gist of the present invention is that the present invention is characterized in that the present invention is characterized in that it is provided with a control means for controlling the clutch means and the differential limiting means according to the motion state of the vehicle.

(Function) According to the vehicle driving force distribution device according to the present invention, the first
Since the torque of each output shaft can be changed individually by the clutch means and the second clutch means, and the differential of the differential mechanism can be changed independently from each clutch means, the driving force distribution ratio can be changed. can be adjusted over a wide range, allowing the optimum driving force distribution ratio to be set for the vehicle's driving conditions.

Further, since it is sufficient to provide the differential mechanism with differential limiting means such as a hydraulic clutch, the differential mechanism does not need to be enlarged.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a power transmission system according to an embodiment in which the driving force distribution device of the present invention is applied to a center differential of a four-wheel drive vehicle.

In the figure, 11 is an engine, 12 is a transmission assembled integrally with the engine 11, and the transmission 12 has a drive gear 13a fixed to an output shaft 13, and a center differential having a differential limiting function via the drive gear 13a. It is connected to 19. The center differential 19 includes a well-known differential mechanism 14 and a differential limiting clutch 15 consisting of a hydraulic multi-disc clutch. In the differential mechanism 14, a driven gear 16a that meshes with the drive gear 13a is fixed to the outer periphery of a hollow differential case 16, and a pair of mate gears 17a, 17b and a mate gear 17a are provided inside the case 16, facing each other.

A pair of side gears 18a mesh with gear 17b.

18b is rotatably supported. These side gears 18a and 18b each have an output shaft 20. which rotatably penetrates the case 16 and extends back and forth. .

20R is fixed, and a differential limiting clutch 15 is disposed between the output shaft 20R and the case 16.

The output shafts 20F and 20R are connected to a front clutch 21° and a rear clutch 21R, respectively, which are hydraulic multi-plate clutches for adjusting driving force.

The differential limiting clutch 15 includes a plurality of plates 15a integrally rotatably supported on the inner wall of the case 16 and an output shaft 20R.
A plurality of plates 15b, which are integrally and rotatably supported by the
, 15b are pressed by a hydraulic actuator 22, which will be described later, to transmit torque. The differential limiting clutch 15 changes the transmission torque (transmission capacity) according to the pressing force of the hydraulic actuator 22, and limits the differential. Front clutch 21. are respectively drum 23. A plate 24a, which is integrally rotatably supported on the inner wall of the rotor, and a plurality of plates 24b, which are supported by an intermediate shaft 25F, are arranged alternately so as to be in frictional contact with each other, and these plates 24a and 24b are pressed by a hydraulic actuator 262 to generate torque. introduce. In addition, the rear clutch 21R and the front clutch 21. The hydraulic actuator 26R presses the plates 24a and 24b to connect the drum 23R and the intermediate shaft 25R.
transmits torque between the These clutches 21r,
21R also has a transmission torque (transmission capacity) that changes depending on the pressing force of the hydraulic actuators 26r and 26R. The front clutch 212 is a drum 23. is the output shaft 20. The intermediate shaft 25 is fixed to the front differential 27F.
The rear clutch 21R has a drum 23R fixed to an output shaft 20R and an intermediate shaft 25R connected to a rear differential 27R. Front differential 27. As is well known, the side gears are connected to the left and right front wheels 29. through axles 2BrL and 28Fl+, respectively.
The front wheel 29 is connected to the
．． ,．． Convey to 29□. Similarly, for the rear differential 27R, the side gear is the axle 28 RL, 2
The driving force is transmitted to the left and right rear wheels 29R and 29RR via 8 RR, and the driving force is transmitted to the rear wheels 29 RL and 29 by allowing a differential.
Convey to RR.

Hydraulic actuator 22. 2Sr and 26R are each independently connected to the control unit 30, and are operated by being supplied with hydraulic pressure from the control unit 30. A sensor 31 that detects vehicle conditions such as vehicle speed, steering angle, longitudinal acceleration, lateral acceleration, wheel rotation speed, and loaded load is connected to the control unit 30, and the sensor 31 outputs a detection signal to the control unit 30. .

The control unit 30 is controlled by a control circuit having a microcomputer and a control circuit to control each actuator 22 . Each actuator 22, 26F includes a hydraulic pressure generating circuit that outputs hydraulic pressure to 26r and 26R, and determines the vehicle state based on the detection signal of the sensor 31, and responds to the vehicle state.

Supply oil pressure to 26R.

Next, the operation of the embodiment will be explained.

The driving force distribution system of this vehicle includes a center differential 19, a differential limiting clutch 15, and a front clutch 2.
1. and a rear clutch 21R are provided, a differential limiting clutch 15 limits the differential between the front and rear wheels, and a front clutch 21. to adjust the driving force of the front wheels 29FL and 29εR, and the rear clutch 21R to adjust the driving force of the rear wheels 29R and 29RR. For this reason, all the driving force is transferred to the rear wheels 29R and 29R.
All the driving force is transmitted to the front wheels from the distribution ratio to the front wheels (29P).
The driving force distribution can be controlled over a wide range up to the distribution ratio transmitted to the 9ER. Also, center differential 19
Since it is sufficient to assemble the differential limiting clutch 15 to the center differential 19, there is no need to increase the size of the center differential 19.

And, this driving force distribution device includes each clutch 15.21.
r, 21* are controlled according to the vehicle condition in the manner shown in Table 1 below to obtain the optimum drive mode for the vehicle condition.

Table 1 In Table 1 above, drive mode A is a four-wheel drive that allows differential differential between the front and rear wheels, drive mode B is a four-wheel drive that directly connects the front and rear wheels, and drive mode C is a two-wheel drive that drives only the front wheels. Two-wheel drive is achieved in which only the rear wheels are driven, and control is performed, for example, in mode A or mode B when driving straight on rough terrain, and in mode C or mode when turning. Therefore, wheel spin or tight corner braking phenomena can be prevented, and good running performance can be obtained.

It goes without saying that the control mode is not limited to the above-mentioned mode, and it is also possible to control the driving force distribution according to the load burden ratio of the front and rear wheels.

FIG. 2 shows a second embodiment in which the driving force distribution device according to the present invention is applied to a rear differential of a four-wheel drive vehicle.

Note that the same parts as in the first embodiment described above are given the same numbers, and the following explanation will be omitted.

As shown in the figure, this driving force distribution device includes an engine 1
1 is connected to the front and rear differentials 27F and 27H via the center differential 19, and the front differential 27. From left and right front wheels 2
9rL and 29pR, the driving force is transmitted from the rear differential 27R to the left and right rear wheels 29R and 29RR. The rear differential 27th is a differential mechanism 14 similar to the center differential 19 of the first embodiment described above.
and a differential limiting clutch 15, and are connected to left and right rear wheels 29R and 29RR via a hydraulic multi-disc left clutch 21L and a right clutch 21R, respectively, whose transmission torque is adjustable. These clutches 21F, 21R
The differential limiting clutch 15 is connected to actuators 26L, 26R, 22 connected to the control unit 30.
The transmission torque is controlled according to the vehicle condition.

Even in the driving force distribution device of the second embodiment, each clutch 15.21F, 21R is controlled in the state shown in Table 2 below according to the vehicle condition, and the front and rear wheels are driven to the optimum state for the vehicle condition. Obtain power distribution.

(Left below) Table 2 In Table 2 above, drive mode A'' is a full-time four-wheel drive that allows normal differential differential between the front and rear wheels, and drive mode B° prohibits differential differential between the left and right rear wheels. Wheel drive, drive mode C° distributes 1/4 of the driving force to the left and right front wheels, and 172 to the left rear wheel.The drive mode D° distributes 174 to the left and right front wheels, and 1/2 to the right rear wheel. A three-wheel drive is achieved that distributes the driving force. Then, when the vehicle turns, the driving mode is changed to Mode C depending on the turning direction.

Alternatively, good turning performance can be obtained by controlling to the mode D°.

FIG. 3 shows a third embodiment in which the driving force distribution device of the present invention is used in a front differential for a front wheel driver.

Also in this third embodiment, the front differential 27F includes a differential mechanism 14 and a differential limiting clutch 15, a left clutch 25PL and a right clutch 21. Left and right front wheels 29PL+ 29E via L
The transmission torque of the clutches 15, 25PL and 25PR is driven by a control unit 30 according to the vehicle condition to control driving force distribution.

In this third embodiment, each clutch has 15.25 PL.

252R is controlled as shown in Table 3 below.

Table 3 In Table 3 above, drive mode a indicates a normal mode that allows differential movement between the left and right front wheels, drive mode directly connects the left and right front wheels, and drive mode C drives only the left front wheel. , drive mode d drives only the right front wheel.

It goes without saying that the third embodiment described above can also be applied to a rear differential of a rear wheel drive vehicle to achieve a similar configuration.

(Effects of the Invention) As explained above, according to the vehicle drive force distribution device according to the present invention, the drive distribution ratio of the drive wheels can be adjusted over a wide range according to the vehicle condition without increasing the size. Performance can be further improved.

[Brief explanation of drawings]

1 to 3 are skeleton diagrams of a power transmission system showing a driving force distribution device for a vehicle according to an embodiment of the present invention, and FIG.
FIG. 2 shows the second embodiment, and FIG. 3 shows the third embodiment. 11...Engine 14...Differential mechanism 15...Differential limiting clutch 19 Center differential 20L 20RR...Output shaft 21F, 21L, 21R, 21L...Clutch 22.
...Hydraulic actuator 26F, 26R, 26L, 21 R...Hydraulic actuator 27F...Front differential 27R...
Rear differential 29 PL, 29 IIL, 29 FR, 29RR
...Wheel 30...Control unit 31...Sensor

Claims (2)

[Claims] (1) The engine is equipped with a differential mechanism in which an input shaft is connected to one drive wheel, a first output shaft is connected to the other drive wheel, and a second output shaft is connected to the other drive wheel, and the differential mechanism allows engine power to be transferred to each drive wheel. A driving force distribution device for a vehicle that allows and transmits a differential to drive wheels, comprising: a differential limiting means that can limit the differential of the differential mechanism; and a differential limiting means that can adjust the transmission torque of the first output shaft. 1 clutch means, a second clutch means capable of adjusting transmission torque of the second output shaft, the second clutch means, the first clutch means;
A driving force distribution device for a vehicle, comprising: a clutch means and a control means for controlling the differential limiting means according to a motion state of the vehicle. (2) The differential limiting means, the first clutch means, and the second clutch means each include a hydraulic clutch with variable torque transmission capacity.
A driving force distribution device for a vehicle described in .