JPH0557131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a four-wheel drive vehicle (4WD vehicle) in which front wheels and rear wheels can be driven by the same engine, and particularly to a transistor clutch device thereof.

[Conventional technology]

Conventionally, for example, front wheel drive base (FF base)
Various types of vehicles have been developed in which drive connection of the rear wheels can be achieved by coupling a hydraulically actuated clutch.

In order to operate this clutch, an oil pump is provided separately (an electric oil pump or an oil pump for automatic transmissions is used as this oil pump), and the discharge pressure of this oil pump is adjusted appropriately to supply the oil to the clutch. supply.

[Problem that the invention seeks to solve]

However, with such conventional transfer clutch devices for four-wheel drive vehicles, there are problems in that the oil pump must be installed separately and the means for adjusting the discharge pressure of the oil pump is complicated. .

The present invention aims to solve these problems, and provides a transfer valve for four-wheel drive vehicles that has a compact structure and can automatically adjust the discharge pressure from an oil pump with a simple structure. The object of the present invention is to provide a clutch device.

[Means for solving problems]

For this reason, the transfer clutch device for a four-wheel drive vehicle of the present invention is provided in a four-wheel drive vehicle in which the front wheels and the rear wheels can be driven by the same engine. In addition to being equipped with a second rotating shaft that transmits driving force to the rear wheels,
A power transmission system for transmitting power from the engine is provided on one of these rotating shafts, and the oil pump is driven by a difference in rotational speed between the first rotating shaft and the second rotating shaft; A clutch is provided between the rotary shaft and the second rotary shaft to supply a discharge pressure of the oil pump according to the rotational speed difference to the clutch tangential control side oil chamber,
It is characterized by an oil passage connecting the oil pump and the clutch.

[Effect]

With the above configuration, when a rotation speed difference occurs between the front wheel side first rotation shaft and the rear wheel side second rotation shaft, the oil pump discharges a discharge pressure corresponding to the rotation speed difference, This discharge pressure is supplied to the tangential control side oil chamber of the clutch via the oil passage.

〔Example〕

Hereinafter, four embodiments of the present invention will be described with reference to the drawings.
To explain the transfer clutch device for a wheel drive vehicle, Fig. 1 is a partial cross-sectional view showing the main parts thereof;
FIG. 2 is a schematic configuration diagram showing the power system of a vehicle equipped with this device, FIG. 3 is a hydraulic circuit diagram for the oil pump, and FIG. 4 is a graph for explaining its operation.

As shown in FIG. 2, the present invention provides front wheels 43, 4
The present invention relates to a four-wheel drive vehicle in which both rear wheels 52 and 53 can be driven by the same engine 1. To further explain the details, as shown in FIGS. 1 and 2,
A transmission 2 constituting a power transmission system T is connected to a horizontally mounted engine 1, and its drive gear (or 4
A gear 7 that is integrated with a sheath shaft 5 that constitutes a first rotating shaft that transmits driving force to front wheels 43 and 44 meshes with the speed counter gear 3.

A front wheel drive shaft 4 (hereinafter referred to as "front wheel output shaft 4") is spline-fitted to this sheath shaft 5 with gear 7, and this front wheel output shaft 4 and sheath shaft 5 are connected to each other by the above-mentioned It constitutes a first rotating shaft.

In this way, power from the power transmission system T is always transmitted to the first rotating shaft.

Further, the present transfer clutch device 13 is connected to the first
Between the sheath shaft 5 that constitutes a rotating shaft and the rear wheel drive shaft 6 (hereinafter referred to as "rear wheel output shaft 6") that constitutes a second rotating shaft that transmits driving force to the rear wheels 52, 53. is interposed in.

This transfer clutch device 13 has a sheath shaft 5
Furthermore, a gear type oil pump 14 is driven by the rotational speed difference between the front wheel output shaft 4 and the rear wheel output shaft 6 and discharges oil at a pressure corresponding to this rotational speed difference.
and a clutch 32 that receives oil discharged from the oil pump 14 through an oil passage to adjust the degree of coupling between the front wheel output shaft 4 side and the rear wheel output shaft 6 side to suppress the rotational speed difference. It is constructed in advance.

Next, these oil pump 14 and clutch 32
The following describes the arrangement of the .

As shown in FIG. 1, the case 15 is attached to the sheath shaft 5.
are spline-fitted, and an oil pump 14 is provided within this case 15.

The oil pump 14 includes an inner gear 17 as an external gear spline-fitted to the rear wheel output shaft 6;
It has an outer gear 18 as an internal gear that meshes with the inner gear 17 but is disposed eccentrically from the inner gear 17, and the inner gear 17 and the outer gear 18 are provided inside the pump case 16.

The pump case 16 is fixed to the case 15 with bolts 19, and the pump case 16 is fixed to the case 15 with bolts 19.
A part 16a of 6 is inserted.

In addition, this oil pump 14 is formed with two ports 20 and 21 as shown in FIG. It is connected to the oil suction port 22 which opens at the shaft end of the rear wheel output shaft 6, and is connected to the discharge oil passage 29 via the oil passage 294 and the three-way check valve 28.
The other port 21 is connected to the oil passage 293, the check valve 25, and the suction oil passage 2.
It is connected to the oil suction port 22 via the oil inlet port 91, and to the discharge oil path 29 via the oil path 295 and the three-way check valve 28.

Furthermore, an oil passage 296 with a relief valve 26 is interposed between the oil passages 291 and 292, and an oil passage 297 with a relief valve 27 is interposed between the oil passages 291 and 293.

In addition, an air-opening oil passage 298 with an orifice 30 branches from the oil passage 294, and the oil passage 298
From 95, there is an oil passage 2 that is open to the atmosphere with an orifice 31.
99 are branching.

As a result, if a rotational speed difference occurs between the front wheel output shaft 4 side and the rear wheel output shaft 6 side, the inner gear 1
7 rotates in the direction of arrow a, oil flows through the oil suction port 22, oil passage 291, check valve 25,
After being sucked into port 21 through oil passage 293,
The oil is discharged from the oil passage 29 via the port 20, the oil passage 294, and the check valve 28. The discharge pressure characteristics at this time are shown by the symbol A in FIG.

Conversely, when the inner gear 17 rotates in the direction of arrow b, the oil flows through the oil suction port 22, oil passage 291,
After being sucked into the port 20 through the check valve 24 and the oil passage 292, the air is sucked into the port 21 and the oil passage 29.
5. It is discharged from the oil passage 29 via the check valve 28. The discharge pressure characteristics at this time are shown in Figure 4 with the symbol B.
It will be shown as follows.

In each of the characteristics A and B, when the rotational speed difference exceeds a certain value, the discharge pressure hardly increases because the relief valves 26 and 27 open when the discharge pressure exceeds the respective predetermined value.

In addition, the relief valve 2 for each characteristic A and B
The characteristic part before 6 and 27 open is orifice 3.
0.31, it is proportional to the square of the rotational speed difference.

Here, since the opening characteristics of the relief valves 26 and 27 and the degree of restriction of the orifices 30 and 31 are changed as appropriate, the characteristics A and B are different, but if these characteristics A and B are the same, It's okay.

Note that a part of the oil passage 291 is connected to the rear wheel output shaft 6.
An oil filter 23 is provided in a portion of the oil passage 291 near the oil suction port 22 .

By the way, as shown in FIG. 1, an annular step is formed on the outer periphery of the pump case 16, and an annular piston 36 is fitted into this step. As a result, an oil chamber 37 (this is a clutch tangential control side oil chamber) is formed between the piston 36 and the pump case 16.

An oil passage 29 opens into this oil chamber 37 .

Therefore, the piston 36 is pushed out by the oil discharged from the oil passage 29.

A clutch 32 is provided adjacent to the piston 36 and is brought into contact when the piston 36 is pushed out in this manner.

The clutch 32 includes a plurality of annular clutch plates 33 spline-engaged with the case 15, and a rear wheel output shaft 6.
The clutch plate 34 includes a plurality of annular clutch plates 34 spline-engaged with a sleeve 35, and the clutch plates 33 and 34 are arranged alternately.

Therefore, when the piston 36 is pushed out,
The clutch plates 33 and 34 are brought into close contact with each other, and the case 15 and the sleeve 35, that is, the front wheel output shaft 4 side and the rear wheel output shaft 6 side are engaged. At this time, the piston 3
Since the force for pushing out the clutch 32 changes, the degree of engagement of the clutch 32, that is, the degree of torque transmission, changes accordingly.

Note that the reference numeral 54 in FIG. 1 indicates a stopper member.

The oil passages 298 and 299 are connected to the clutch 32.
(The pressure in this part is atmospheric pressure)
This opens the oil passages 298 and 299.
The clutch 32 can be cooled and lubricated by the oil from the clutch 32.

By the way, as shown in FIG. 2, a gear 38 is attached to the front wheel output shaft 4, and this gear 38 meshes with a ring gear 39 of a front wheel differential mechanism 40 (hereinafter referred to as "front wheel differential 40"). are doing. As a result, the torque from the front wheel output shaft 4 is divided by the front wheel differential 40 and left and right front wheel shafts 41, 42.
The front wheels 43 and 44 are transmitted to the front wheels 43 and 44 to rotate.

Further, the rear wheel output shaft 6 is connected to a propeller shaft 47 via a bevel gear mechanism 45, and a bevel gear 47a of this propeller shaft 47 is connected to a rear wheel differential mechanism 49 (hereinafter referred to as "rear wheel differential 49"). The ring gear 48 meshes with the ring gear 48. As a result, the torque from the rear wheel output 6 is divided by the rear wheel differential 49 and transmitted to the left and right rear wheel shafts 50, 51.
53 is driven to rotate.

With the above configuration, when the front wheels 43 and 44 slip while driving in front wheel drive and the rotational speed on the front wheel output shaft 4 side becomes faster than the rotational speed on the rear wheel output shaft 6 side, the inner gear 17 rotates in the direction of arrow a. As a result, oil is sucked from the port 21 via the oil suction port 22, the oil passage 291, the check valve 25, and the oil passage 293.
0, is discharged from the oil passage 29 into the oil chamber 37 via the oil passage 294 and the check valve 28. Since this discharge pressure has a value corresponding to the rotational speed difference between the front wheel output shaft 4 side and the rear wheel output shaft 6 side, the force with which the piston 36 presses the clutch plates 33 and 34 is also determined according to the rotational speed difference. As a result, the amount of torque transmitted by clutch 32 also varies depending on the rotational speed difference.

When a rotational speed difference occurs in this way, the clutch 32 is brought into contact with a degree of coupling corresponding to this difference, so the rotational speed difference is suppressed, and as a result, the rear wheel output shaft 6 side is Torque is also transmitted.
If the front wheels 43, 44 are spinning as a result, the system automatically switches to four-wheel drive and the rear wheels 52, 54
can be rotated.

At this time, the clutch 3
Since the amount of transmitted torque is automatically controlled by 2,
It does not cause deterioration of driving feeling or steering stability.

In particular, the rising part of characteristic A shown in FIG.
Since it is proportional to the square of the rotational speed difference, almost no torque is transmitted with a small rotational speed difference, which also has the advantage of avoiding braking reduction when turning at low speeds.

Furthermore, since the clutch 32 is of a type in which the clutch plates 33 and 34 are pressed against each other by the piston 36, the structure can be made more compact.

Note that when the rotational speed difference exceeds a certain value, for safety reasons, the relief valve 27 acts to suppress the increase in the discharge pressure.

Conversely, if the rear wheels 52, 53 turn faster than the front wheels 43, 44, the inner gear 17 is automatically shifted.
rotates in the direction of arrow b. As a result, the oil supply path is automatically switched, and the oil is supplied to the oil suction port 22, the oil path 291, and the check valve 2.
4. Inhaled from port 20 via oil path 292,
The oil is discharged from the oil passage 29 into the oil chamber 37 via the port 21, the oil passage 295, and the check valve 28. Since this discharge pressure also has a value corresponding to the rotational speed difference between the front wheel output shaft 4 side and the rear wheel output shaft 6 side, the force with which the piston 36 presses the clutch plates 33 and 34 is determined according to the rotational speed difference. As a result clutch 3
The magnitude of the torque transmitted by 2 also changes depending on the rotational speed difference.

In this case as well, since the clutch 32 is brought into contact with a degree of coupling depending on the rotational speed difference, the rotational speed difference is suppressed, and as a result, torque is also transmitted to the front wheel output shaft 4 side. As a result, the rear wheel 52,
The rotation of the front wheels 43 and 44 can be driven while suppressing the rotation of the front wheels 53.

Also in this case, since the amount of torque transmitted by the clutch 32 is automatically controlled in accordance with the rotational speed difference, the driving feeling and steering stability are not deteriorated. In particular, since the rising portion of characteristic B shown in FIG. 4 is also proportional to the square of the rotational speed difference, the same effect or advantage as in the above case can be obtained.

In this case as well, if the rotational speed difference exceeds a certain value, the relief valve 26 acts to suppress the increase in the discharge pressure for safety.

In addition, in this device, the product of the transmitted torque and the rotational speed difference becomes energy loss and generates heat.
Since a portion of the oil is discharged to the clutch 32 through the oil passages 298 and 299, there is an advantage that the clutch 32 can be sufficiently cooled and lubricated.

Note that this device can also be applied to a four-wheel drive vehicle based on rear wheel drive, but in this case, the power from the engine is normally transmitted to the second rotating shaft.

Further, the oil pump 14 is not limited to a gear type oil pump, and other oil pumps can be incorporated and used in the same manner as in the above embodiment.

〔Effect of the invention〕

As described in detail above, according to the transfer clutch device for a four-wheel drive vehicle of the present invention, in a four-wheel drive vehicle in which the front wheels and the rear wheels can be driven by the same engine, the transfer clutch device for transmitting driving force to the front wheels can be used. a second rotating shaft that transmits driving force to the rear wheels; a power transmission system that transmits power from the engine to one of these rotating shafts; An oil pump driven by the difference in rotational speed with the second rotating shaft, and a clutch interposed between the first rotating shaft and the second rotating shaft are provided. In order to supply the corresponding discharge pressure of the oil pump to the tangential control side oil chamber of the clutch, the simple structure includes an oil passage connecting the oil pump and the clutch. If a difference occurs, the system automatically switches to four-wheel drive mode, and the amount of torque transmitted by the clutch can be automatically controlled according to the difference in rotational speed, so there is no possibility of deterioration in driving feeling or steering stability. Moreover, it has the advantage of contributing to a more compact structure and lower costs.

[Brief explanation of drawings]

The figures show a transfer clutch device for a four-wheel drive vehicle as an embodiment of the present invention. Fig. 1 is a partial sectional view showing the main parts thereof, and Fig. 2 is a power system of a vehicle equipped with this device. 3 is a hydraulic circuit diagram for the oil pump, and FIG. 4 is a graph for explaining its operation. DESCRIPTION OF SYMBOLS 1...Engine, 2...Transmission, 3...Drive gear, 4...Front wheel output shaft constituting the first rotating shaft, 5...Rear wheel output shaft, 6...Rear wheel output shaft, 7...Gear, 13...Transfer clutch device, 14...
...Oil pump, 15...Case, 16...Pump case, 16a...Pump case part, 17...
...Inner gear, 18...Outer gear, 19...Bolt, 20, 21...Port, 22...Oil inlet, 23...Oil filter, 24, 25...
Check valve, 26, 27... Relief valve, 28... Check valve, 29... Oil path, 3
0, 31... Orifice, 32... Clutch, 3
3, 34...Clutch plate, 35...Sleeve, 3
6... Piston, 37... Oil chamber, 38... Gear,
39...Ring gear, 40...Front wheel differential, 4
1,42...Front wheel axle, 43,44...Front wheel, 45
...Bevel gear mechanism, 47...Propeller shaft, 47
a...Bevel gear, 48...Ring gear, 49...
... Rear wheel differential, 50, 51 ... Rear wheel axle, 52, 5
3... Rear wheel, 54... Stopper member, 291-2
99...Oil passage, T...Power transmission system.

Claims (1)

[Claims] 1. A four-wheel drive vehicle in which front wheels and rear wheels can be driven by the same engine, including a first rotating shaft that transmits driving force to the front wheels, and a second rotating shaft that transmits driving force to the rear wheels. , a power transmission system for transmitting power from the engine to one of these rotating shafts, and an oil pump driven by a difference in rotational speed between the first rotating shaft and the second rotating shaft; A clutch is provided between the first rotating shaft and the second rotating shaft, and is configured to supply a discharge pressure of the oil pump according to the rotational speed difference to the tangential control side oil chamber of the clutch. A transfer clutch device for a four-wheel drive vehicle, characterized in that an oil passage connecting the oil pump and the clutch described above is provided.