JPS6332649B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to an overdrive type part-time four-wheel drive system.

<Prior art> Four-wheel drive systems are divided into two types: a full-time four-wheel drive system that transmits power to all four wheels at all times, and a four-wheel drive system that normally transmits power to either the front or rear wheels and is used when driving on snowy roads. There is a part-time four-wheel drive system that transmits power to the front and rear wheels when operated by a person.

By the way, when a vehicle turns along a curve, the front wheels need to rotate with a larger turning radius than the rear wheels, and the rotation speed of the front wheels becomes faster than that of the rear wheels. Therefore, in a four-wheel drive vehicle, tire slippage increases when the vehicle turns along a curve in a four-wheel drive state. Tires cannot withstand such adverse conditions for long periods of time, and furthermore, undue strain occurs in the drive and fuel consumption increases. Therefore, always 4
A full-time four-wheel drive system that runs in wheel drive mode is equipped with a third differential device in addition to the front and rear wheel differential devices, and this third differential device rotates the front and rear wheel drive shafts. However, the third differential device absorbs slippage between the front and rear wheel drive shafts.
In this case, if one wheel loses traction on a slippery surface such as an icy surface on the road, the other wheel also loses driving force, so the third differential locks the differential operation. equipment is provided.

On the other hand, many part-time four-wheel drive systems do not have a third differential because they are usually two-wheel drive.

<Problems to be Solved by the Invention> However, even with part-time four-wheel drive systems, depending on the conditions of use, the vehicle often travels in four-wheel drive mode, making it difficult to add a third differential. desired.

Furthermore, in part-time four-wheel drive vehicles, in order to improve fuel efficiency during two-wheel drive during normal driving, it is desired to have a multi-stage transmission or add an overdrive device.

However, when attempting to provide a third differential device to a four-wheel drive device, make the transmission multi-speed, or add an overdrive device, the problem was that the four-wheel drive device became too large to be mounted on a vehicle. .

Therefore, the present invention uses the planetary gear mechanism that constitutes the third differential during four-wheel drive as an overdrive device during two-wheel drive, thereby enabling overdrive driving during two-wheel drive and improving fuel efficiency. At the same time, the part-time 4-wheel drive system with overdrive is compactly configured to improve durability by absorbing slippage between the front and rear wheels during 4-wheel drive, making it easier to mount on vehicles. be.

<Means for Solving the Problems> The part-time four-wheel drive device with overdrive of the present invention includes a rear wheel drive output shaft provided coaxially with an output shaft of a transmission, and the rear wheel drive output shaft. a front wheel drive output shaft provided in parallel with the transmission; a planetary gear that is provided concentrically with the output shaft of the transmission and includes a sun gear, a ring gear, a planetary pinion that meshes with both gears, and a carrier that supports the planetary pinion; an output shaft of the transmission is connected to a carrier of the planetary gear mechanism, a ring gear of the planetary gear mechanism is connected to the rear wheel drive output shaft, and a sun gear of the planetary gear mechanism is connected to a carrier of the planetary gear mechanism. The carrier of the planetary gear mechanism is coupled to an intermediate shaft rotatably disposed on the output shaft, and the carrier of the planetary gear mechanism is removably coupled to a sun gear by a wet friction clutch, and the sun gear of the planetary gear mechanism is selectively coupled to the sun gear by a wet friction brake. and the intermediate shaft is configured to be detachably connected to the front wheel drive output shaft by a wet friction selective clutch device.

<Operations and Effects of the Invention> The present invention connects the output shaft of the transmission to the carrier of the planetary gear mechanism, connects the ring gear of the planetary gear mechanism to the rear wheel drive output shaft, and connects the sun gear of the planetary gear mechanism to the carrier of the planetary gear mechanism. It is connected to an intermediate shaft rotatably disposed on the output shaft, the carrier of the planetary gear mechanism is removably connected to the sun gear by a wet friction clutch, and the sun gear of the planetary gear mechanism is selectively fixed by a wet friction brake. , the intermediate shaft is configured to be removably connected to the front wheel drive output shaft by a wet friction selection clutch device, so that when the wet friction selection clutch device is released and the wet friction clutch is engaged, the two-wheel drive direct coupling drive is activated. can be achieved, two-wheel drive overdrive drive can be achieved when the wet friction selection clutch device is disengaged and the wet friction brake is engaged, and the wet friction selection clutch device is engaged and the wet friction clutch and brake are released. When the planetary gear mechanism performs differential operation 4
When the wet friction selective clutch device is engaged and the wet friction clutch is engaged, the planetary gear mechanism is locked and four-wheel drive is achieved without differential operation.

Further, according to the present invention, the output shaft of the transmission is connected to the carrier of the planetary gear mechanism, the ring gear of the planetary gear mechanism is connected to the rear wheel drive output shaft, and the sun gear of the planetary gear mechanism is connected to the output shaft of the transmission. The carrier of the planetary gear mechanism is removably connected to the sun gear by a wet friction clutch, the sun gear of the planetary gear mechanism is selectively fixed by a wet friction brake, and the intermediate shaft is connected to a rotatably arranged intermediate shaft. By configuring the wet friction selection clutch device to be removably connected to the front wheel drive output shaft, the planetary gear mechanism that constitutes the third differential during four-wheel drive can be
Since it can be used as an overdrive device when driving two wheels, it is possible to drive in overdrive when driving two wheels, improving fuel efficiency, and when driving four wheels, it can absorb slippage between the front and rear wheels and improve durability. It becomes possible to configure a part-time four-wheel drive device with a drive compactly, and it has the effect of improving the mountability on a vehicle.

Further, according to the present invention, a selection clutch for switching between two-wheel drive and four-wheel drive, a brake for obtaining overdrive during two-wheel drive, and a clutch for locking the third differential during four-wheel drive are provided. Since the system is composed of a wet friction multi-plate friction engagement device, driving patterns such as 2-wheel drive and 4-wheel drive can be selected depending on various driving conditions while the vehicle is running, improving drivability. It has a good effect.

<Example> Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an automobile to which the four-wheel drive device of the present invention is applied. The automobile has an engine 1 and a transmission 2 connected to the engine 1.
The four-wheel drive device 3 is connected to the transmission 2, and also to the rear wheel drive shaft 4 and the front wheel drive shaft 5. The rear wheel drive shaft 4 and the front wheel drive shaft 5 each have a differential device 6,
7 to transmit torque to the rear wheels and front wheels.

FIG. 2 is a sectional view showing an example of the four-wheel drive device of the present invention. An output shaft 10 of the transmission 2 is connected to a planetary gear mechanism 20.

The planetary gear mechanism 20 includes a planetary carrier 21 connected to the output shaft 10, a pinion gear 22 supported by a pinion shaft 21a of the planetary carrier 21, a ring gear 23 and a sun gear 24 that mesh with the pinion gear 22, and the ring gear 23 is connected to the rear. It is connected to a rear wheel drive output shaft 13 that drives the wheel drive shaft 4 . The sun gear 24 is connected to one end of an intermediate shaft 14 rotatably disposed on the output shaft 10, and an output selection clutch device 30 is provided at the other end of the intermediate shaft 14. Also, intermediate shaft 1
A clutch cylinder 25 is connected to the clutch cylinder 4, and a clutch device 26 is provided between the clutch cylinder 25 and a clutch hub 27 fixed to the planetary carrier 21 to detachably connect the two. Further, the clutch cylinder 25 is provided with a brake device 28.

The output selection clutch device 30 includes a clutch cylinder 31 spline-fitted to the intermediate shaft 14, a clutch hub 33 fixed to a transmission gear 32 rotatably disposed on the output shaft 10, and a clutch cylinder 3.
1 and a clutch plate 34 disposed between the clutch hub 33. The transmission gear 32 transmits torque through a chain 38 to a gear 37 provided on the front wheel drive output shaft 15 arranged parallel to the output shaft 10 of the transmission. The front wheel drive output shaft 15 drives the front wheel drive shaft 5.

FIG. 3 is a block diagram of the clutch control means for controlling the operation of clutch 26. 50 is a vehicle speed sensor provided on the front wheel drive output shaft, 60 is a vehicle speed sensor provided on the rear wheel drive output shaft, and 70 is a clutch sensor that detects the engagement state of the selection clutch device. 80 is a logic circuit that inputs signals from the vehicle speed sensors 50, 60 and the clutch sensor 70 and outputs an output signal for exciting a solenoid for operating the clutch 26; 90 inputs the output signal of the logic circuit 80; This is a solenoid means that de-energizes the solenoid and supplies pressure oil to the clutch 26. 110 is a brake engagement means for controlling ON/OFF of the brake 28.

This clutch control means operates as follows.

During two-wheel drive...The selection clutch device 30 is in the released state, the solenoid is not energized, and the clutch 26 is not energized.
Pressure oil is supplied to the clutch 26, the clutch 26 is engaged, the planetary gear mechanism rotates as a unit, and the vehicle is driven in a two-wheel drive directly connected state.

When the vehicle speed reaches a predetermined speed or higher from this state, the clutch 26 is released and the brake 28 is engaged, the planetary gear mechanism acts as an overdrive device, and the vehicle is driven in a two-wheel drive overdrive state.

During four-wheel drive...When the selection clutch device 30 is in the engaged state and the vehicle is at a predetermined vehicle speed or less, or when the rotation difference between the front and rear wheel output shafts exceeds a predetermined value outside of normal driving, i.e. Clutch 26 is engaged only when one wheel is on a frozen surface or the like. At other times, that is, during normal driving, the solenoid is energized and the clutch 26 is released.

If the electrical circuit, vehicle speed sensors 50, 60, position sensor 70, etc. fail, the solenoid will not be energized and the clutch 26 will be engaged.

Next, the operation of the four-wheel drive system of the present invention will be explained.

During two-wheel direct-coupling drive... Since the selection clutch device 30 is in the released state, the intermediate shaft 14 is not coupled to the front-wheel drive output shaft 15. Further, the clutch 26 is engaged by the clutch control means to connect the planetary carrier 21 of the planetary gear mechanism and the sun gear 24 connected to the clutch cylinder 25.

Power from the output shaft 10 of the transmission is transmitted to a planetary carrier 21 of the planetary gear mechanism. At this time, by engagement of the clutch 26, the planetary gear mechanism is integrated and rotates in a locked state, driving the rear wheel drive output shaft 13 via the ring gear 23. Since the intermediate shaft 14 connected to the sun gear 24 is in a free state, no power is transmitted to the front wheel drive output shaft 15.

During two-wheel overdrive driving...When the vehicle speed increases during two-wheel direct drive driving and the clutch control means switches to overdrive driving, the clutch 26 is released and the brake 28 is engaged. Since the sun gear 24 is fixed when the brake 28 is engaged, the power from the output shaft 10 of the transmission is increased in speed and transmitted to the rear wheel drive output shaft 13, resulting in a so-called overdrive state.

During four-wheel drive... Since the selection clutch device 30 is in the engaged state, the intermediate shaft 14 is connected to the transmission gear 32 and further connected to the front wheel drive output shaft 15 via the chain 38 and gear 37.

When starting in 4-wheel drive, or when the rotational difference between the front and rear wheel drive output shafts exceeds a predetermined value outside of normal driving, that is, when one wheel is on a frozen surface, muddy surface, etc., the clutch control means activates the clutch. 26 is engaged and the planetary gear mechanism 20 is in a locked state. The power from the output shaft 10 of the transmission is transmitted to the rear wheel drive output shaft 13 as in the case of two-wheel drive, and is also transmitted to the front wheel drive output shaft 15 via the selection clutch device 30.
is transmitted to.

During normal four-wheel drive driving, the clutch 26 is released by the clutch control means, and the planetary gear mechanism 20
acts as a differential device and performs differential operation. The power from the output shaft 10 of the transmission is transmitted to the rear wheel drive output shaft 13 and the front wheel drive output shaft 15 as described above. For differential operation, the pinion gear 22 is connected to the intermediate shaft 14
In addition to rotating around the rear wheel drive output shaft 13, it rotates on the pinion shaft 21a to allow relative movement between the ring gear 23 and the sun gear 24, and between the intermediate shaft 14 and the rear wheel drive output shaft 13. Obtained by allowing relative motion.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a car to which the four-wheel drive device of the present invention is applied, FIG. 2 is a sectional view showing an example of the four-wheel drive device of the present invention, and FIG. 3 is shown in FIG. 2 is a block diagram showing clutch control means for controlling the operation of clutch 26 and brake 28; FIG. In the diagram, 1...engine, 2...transmission, 3...
4-wheel drive device, 4... Rear wheel drive shaft, 5... Front wheel drive shaft, 6... Rear wheel differential device, 7... Front wheel differential device, 10... Output shaft of transmission, 13... Rear Wheel drive output shaft, 14... Intermediate shaft, 15... Front wheel drive output shaft, 20... Planetary gear mechanism, 21... Planetary carrier, 21a... Pinion shaft, 22...
...Pinion gear, 23...Ring gear, 24...
Sun gear, 26...clutch, 28... brake, 30... selection clutch device, 32, 37...
Transmission gear, 38...chain.

Claims (1)

[Claims] 1. A rear wheel drive output shaft provided coaxially with the output shaft of the transmission, a front wheel drive output shaft provided parallel to the rear wheel drive output shaft, and a front wheel drive output shaft provided concentrically with the output shaft of the transmission. , a planetary gear mechanism including a sun gear, a ring gear, a planetary pinion meshing with both gears, and a carrier supporting the planetary pinion, the output shaft of the transmission is connected to the carrier of the planetary gear mechanism, and the planetary gear mechanism A ring gear of the gear mechanism is connected to the rear wheel drive output shaft, a sun gear of the planetary gear mechanism is connected to an intermediate shaft rotatably disposed on the output shaft of the transmission, and a carrier of the planetary gear mechanism is connected to the rear wheel drive output shaft. The sun gear of the planetary gear mechanism is selectively fixed by a wet friction brake, and the intermediate shaft is removably connected to the front wheel drive output shaft by a wet friction selective clutch device. A part-time four-wheel drive device with an overdrive, characterized in that the part-time four-wheel drive device is configured to