JPH0343052Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drive system for a four-wheel drive vehicle having a differential gear.

[Conventional technology]

There are two types of drive systems for conventional four-wheel drive vehicles with differentials. In other words, it has three differential devices at the center (inside the transfer) and at the front and rear axles.
There are full-time 4-wheel drive vehicles that distribute differential transmission between the front and rear axles, and part-time 4-wheel drive vehicles that have a transmission that directly connects the driving force to the front and rear axles and can connect one to the other. .

[Problem that the invention seeks to solve]

In a four-wheel drive vehicle with the conventional differential device mentioned above, in a part-time four-wheel drive vehicle (front and rear wheels directly connected), the front and rear axles are directly connected, so when turning, the distance traveled by each wheel is reduced due to the difference between the inner wheels. This causes the tires to drag or slip during driving, causing vibrations in the vehicle and causing discomfort. Therefore, when driving on-road, it is customary to switch to two-wheel drive. Also, full-time four-wheel drive vehicles have a center differential, and all four wheels are connected to each other via differential gears, so if one wheel spins in mud, etc., no torque is applied to all other wheels.
Escape from mud etc. becomes disadvantageous. For this reason, there is a need to equip a differential limiting device or differential lock, etc., and drivers have to choose between two-wheel drive, four-wheel drive, full-time four-wheel drive, and part-time four-wheel drive depending on road conditions and driving conditions. In the case of Time 4-wheel drive vehicles, the differential lock can be operated individually.

[Means for solving problems]

The four-wheel drive vehicle of the present invention receives the output of the engine, and one differential connects the front left wheel and the rear right wheel.
A transfer device includes a differential device having an output shaft end corresponding to the four wheels of the vehicle combined so that the other differential device connects with the right front wheel and the left rear wheel, and a transfer device provided inside each wheel. A drive shaft is provided at each output shaft end of the deceleration means and transfer, which connects the deceleration means of each corresponding wheel.

Therefore, although it is full-time four-wheel drive,
There is no center differential, so even if one wheel spins, all other wheels will not stop moving, and when turning, the average rotation speed of the left front wheel and right rear wheel is almost equal to the average rotation speed of the right front wheel and left rear wheel. Even though there is no center differential, there is almost no torque loss such as tire slip or drag due to the difference between the inner wheels, and you can turn freely on the road in 4-wheel drive, making it even smoother on the road. It is. In addition, by changing the gear ratio of the reduction gear between the front and rear, it is possible to completely eliminate slips caused by the difference between the inner wheels when turning.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a power transmission system of an embodiment of a four-wheel drive vehicle of the present invention.

The output of the engine 1 is transmitted from the output shaft 3 to the transfer 4 via the transmission 2.
It meshes with the gear in the transfer 4 and is input to the differential gear 8. The differential device 8 has a shaft end that transmits power to the right front wheel and the left rear wheel, and the differential device 9 also has an output shaft 3 to a gear 5, a case of the differential device 8, and a gear 6 having the same number of teeth. , 7, and has shaft ends that transmit power from the differential device 9 to the left front wheel and the right rear wheel. That is, it has four shaft ends that receive power from the output shaft 3 and transmit power to each wheel, respectively. Each of the left front wheel, right front wheel, left rear wheel, and right rear wheel is equipped with a reduction gear 14, 15, 16, and 17 using bevel gears on the inner surface of the wheel, and the left front wheel, right front wheel, and left Rear wheel,
To the right rear wheel, each output shaft end is connected to a drive shaft 10, 11, 12, 13 via a universal joint, respectively.
is connected to each reduction gear device 14, 15, 16, 17 by.

In this way, the left front wheel and the right rear wheel are connected via the differential device 9, the right front wheel and the left rear wheel are connected via the differential device 8, and the rotational speed of the gear 6 and the gear 7 is equal. In this case, the drive shaft 10 belonging to the differential gear 9
The average rotational speed of the drive shaft 13 and the average rotational speed of the drive shaft 11 and the drive shaft 12 belonging to the differential device 8 are equal to each other.

According to FIG.
The situation when a wheel drive vehicle turns will be explained. FIG. 6 shows the trajectory of the tires of a vehicle turning with its inner wheels cut at 40 degrees. In this case, the left front wheel traces a trajectory A with radius a = 15.39, and the right rear wheel connected to this through the differential gear 9 traces a trajectory D with radius d = 8.94.
draw Also, the right front wheel has a trajectory C with radius c = 11.67.
The left rear wheel connected to this via the differential device 8 draws a trajectory B with b=13.44. Therefore,
The average travel distances of trajectories A and D and the average travel distances of trajectories B and C are as follows.

A+D/2=2π(a+d)/2=76.4349 B+C/2=2π(b+c)/2=78.8854 In other words, the slip rate is 78.8854−76.4349/76.4349×100≒3.2%, and the reduction gears 14, 15, 16, 17 and the tire effective radius are respectively equal, the average rotational speed of the right front wheel and the left rear wheel is approximately equal to the average rotational speed of the left front wheel and the right rear wheel. If the values of B and D are multiplied by a certain constant K, the slip becomes 0. The value of K can be determined by the following formula.

From A+DK/2=BK+C/2 K=C-A/D-B
becomes.

Therefore, if the gear ratio of the front and rear axes of the reduction gear is set using this value of K, slips will not occur at all. In this example, K=0.844...

FIG. 2 shows that the gear 21 and the gear 22 are directly meshed with the gear of the input shaft 3 of the transfer 4.
2 is an output shaft end that transmits power to the left front wheel on one side via the differential device 9, and an output shaft end that transmits power to the right rear wheel via the sprockets 25, 26 and chain 28 on the other side. The gear 21 has an output shaft end that transmits power to the right front wheel via the differential 8 on one side, and a sprocket 23 on the other side.
24 and an output shaft end that transmits power to the left rear wheel via a chain 27. With this structure, the drive shafts 12 and 13 will not intersect when viewed from above.

3 and 4 show two differential devices 8, 9,
This is a method of directly and simultaneously driving the differential pinion gears of the differential devices 8 and 9 using another embodiment of the structure of the transfer 4, which is composed of a gear train and has a shape in which the drive shafts 10 and 11 and 12 and 13 do not intersect. .
FIG. 5 is a perspective view of another embodiment of the present invention similar to FIG. 1, but with drive shafts 10 and 11 and 12 and 13 arranged vertically.

[Effect of idea]

As explained above, according to the present invention, the differential device 2
By connecting the output ends of the transfers with the front left wheel and rear right wheel through one differential device, and the front right wheel and rear left wheel through the other differential device, two sets of The average rotational speed of the drive shafts is almost the same, and there is almost no slippage due to the difference between the inner wheels when turning. Therefore, it is possible to use full-time 4-wheel drive without a center differential, and combines the advantages of conventional full-time 4-wheel drive and part-time 4-wheel drive.In other words, full-time 4-wheel drive on-road You get a new full-time four-wheel drive with the turning ability and traction of a part-time four-wheel drive. Furthermore, there is no need for a deflock device or switching between two-wheel drive and four-wheel drive, and the driver is freed from troublesome operations.

[Brief explanation of the drawing]

FIG. 1 is a top view of one embodiment of the structure of the power transmission system of a four-wheel drive vehicle according to the present invention, FIG. 2, FIG. 3, and FIG.
The figures show different embodiments of the structure of the transfer shaft 4, FIG. 5 is a perspective view of the overall structure of the power transmission system of yet another embodiment, and FIG. 6 is a four-wheel drive system according to the present invention. FIG. 4 is a diagram showing the locus of each wheel when the car turns to the right by cutting the inner wheels at 40 degrees. 1...Engine, 2...Transmission,
3... Output shaft, 4... Transfer, 5, 6, 7
... Gear, 8, 9 ... Differential gear, 10, 11, 1
2, 13... Drive shaft, 14, 15, 16, 17...
...Reduction gear, 21, 22...Gear, 23, 24,
25, 26... Sprocket, 27, 28... Chain.

Claims (1)

[Claims for Utility Model Registration] Assembled so that in response to transmission of engine output, one differential device connects the left front wheel and the right rear wheel, and the other differential device connects the right front wheel and the left rear wheel. a transfer device incorporating a differential device having output shaft ends corresponding to the four wheels of the combined vehicle; a deceleration means provided inside each wheel; and each wheel corresponding to each output shaft end of the transfer A four-wheel drive vehicle comprising a drive shaft to which a deceleration means is connected.