JPS60226326A - Four wheel drive vehicle - Google Patents

Abstract

PURPOSE:To make it possible to change over a hour/two wheel drive changeover means between both operations in a passenger's compartment without a clutch being subjected to excessive shock and load, by engaging the clutch with a some delay from the coupling of transfer upon change-over of the change-over means. CONSTITUTION:One 7a of rear axles is splitted into parts 7a', 7a'' between which a remote controllable clutch 9 is disposed. A vacuum switch valve VSV2 is disposed in the intermediate section of a pipe line 12 connecting between an intake manifold 11 and the clutch 9, and a vacuum switch VSV1 is disposed in the intermediate section of a pipe line 13 connecting between the intake manifold 11 and a transfer 4. A delay circuit D is disposed between a four/two wheel drive change-over switch 14 and the valve VSV2. Due to the provision of the delay circuit D the valve VSV2 is turned into its opened condition with a some delay from the operation of the valve VSV1, and upon changeover the clutch 9 may be engaged with no shock.

Description

[Detailed Description of the Invention] The present invention relates to a four-wheel drive vehicle that can freely switch between so-called two-wheel drive and four-wheel drive, and particularly relates to a four-wheel drive vehicle that can freely switch between two-wheel drive and four-wheel drive. Framed fishing Kanetayu? This invention relates to a four-wheel drive vehicle that can be operated while driving inside the vehicle.

Conventionally, in 4-wheel drive vehicles, each axle shaft that is the drive side during 2-wheel drive and each wheel attached to one end of these shafts is configured to constantly transmit torque, and when 2-wheel drive Torque transmission to each axle shaft on the driven side and each wheel assembled to one end of the axle shaft is disconnected via a freewheel hub clutch.
It is configured so that it can be connected to the drive side during two-wheel drive by cutting off torque transmission between each axle shaft on the driven side and the wheels attached to its end, reducing power loss and vibration of 9M during two-wheel drive.
There are products that are designed to reduce noise.

There is also known a four-wheel drive vehicle (see Japanese Utility Model Publication No. 58-44227) in which one of the two freewheel hub clutches is omitted to reduce costs.

The reason why the axle shaft, which is the driven side during two-wheel drive, and the wheel assembled to one end of the axle shaft are disconnectably connected using a freewheel hub clutch or the like is as follows. That is, during two-wheel drive, the propeller shaft, which is connected to the axle shaft on the driven side at that time via the differential, and the engine are cut off from torque transmission between the two by a transfer provided between the two. Therefore, if both driven wheels remain connected to the axle shaft, both axle shafts rotate in the same direction during driven driving, and the propeller shaft connected thereto via the differential also rotates. Such a propeller shaft has high rotational resistance,
Also, since the 'IN' is large, it causes power loss, vibration, and noise during two-wheel drive.

Therefore, at least one driven wheel and the axle shaft are separated during two-wheel drive, and even if the driven wheels rotate in the same direction, the propeller shaft, which has a large resistance, hardly rotates, reducing power loss, vibration, and noise. This is for the purpose of achieving this goal.

However, such freewheel hub clutches use mechanical means such as screws to disconnect and disconnect the axle shaft from the wheel.
It is difficult to perform intermittent operation remotely from inside the vehicle, much less perform intermittent operation while driving.
Each time switching between wheels and four wheels requires the driver to stop the vehicle, get out of the vehicle, and tighten or loosen the screws of the freewheel hub clutch, which poses a problem in operability.

The present invention aims to improve the operability of a four-wheel drive vehicle that enables switching between two wheels and four wheels as described above, and for this purpose, a remote FM clutch is interposed on the front axle shaft or the rear axle shaft. , it is possible to disconnect and connect the axle shaft and the heavy wheels inside the vehicle, and with this configuration, it is possible to switch from two-wheel drive to four-wheel drive, and to reduce the impact that acts on the clutch at the time of such switching. The gist of this invention is that when switching from two-wheel drive to four-wheel drive for the purpose of mitigation, the remote controlled clutch is engaged later than the transfer is engaged.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples embodying the present invention will be described below with reference to the accompanying drawings to provide an understanding of the present invention.

1 is a schematic configuration diagram showing an example of a power transmission mechanism of a four-wheel drive vehicle according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a horizontal engine, and a pair of left and right front axle shafts 2B, 2t are connected to the engine 1 via a front differential 3. As shown in FIG. l- front differential 3 is transfer 4
and a rear differential 6 via the propeller shaft 5, and left and right rear axle shafts 78 and 7 are connected to the rear differential 6. 8°, 8) is the front axle shaft 2a and 2
This is the front wheel attached to the front. Further, one of the rear axle shafts 7a is divided into two parts 71' and 7a'', and a remotely controllable clutch 9 is interposed between the parts, and the shaft ends of the rear axle shafts 7+1 and 7a'' are Rear wheels 10 and 10 are respectively attached.

Activating the transfer 4 and clutch 9 like this
There are various sources of motion AC, AC, beak < 4k 4
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A negative pressure actuator using a Hano Nonique manifold 11 is adopted, and a vacuum switch valve VSV2 is interposed in the middle of a pipe 12 that connects the intake manifold 11 and the clutch 9. Further, the transfer 4 is of a similar type, and a vacuum switch valve VSV is interposed in the middle of the pipe 13 that connects the intake manifold 11 and the transfer 4.

Vacuum switch valves VSV and SV2 are of a type that connects the transfer 4 and clutch 9 sides to the atmosphere in the closed state (non-excited state). A self-holding 4-wheel/2-wheel selector switch 14 is interposed between both the vacuum switch valves VSV and VSV2 and the power supply that excites them, and is located at an appropriate position in the vehicle interior, for example, on the front panel of the driver's seat. ing. In addition, in this example, the 4-wheel-2-wheel selector switch 14 and the vacuum switch valve S
A delay circuit as shown in the second diagram is interposed between the signal and V2.

Usually, the delay time of this delay circuit is set to about 2 seconds. The four-wheel/two-wheel switching switch constitutes a four-wheel/two-wheel switching wedge means.

Next, the operation of the embodiment 1- will be further explained.

First, when the four-wheel/two-wheel selector switch 14 is in the open state as shown in the figure, both the vacuum isostatic valves VSV and VSV are not energized and are in the closed state, so the transfer 4 and the clutch 9 are No negative pressure is applied. Therefore, both the transfer 4 and the clutch 9 are in a disconnected state in which no torque is transmitted. In this state, engine 1
rotation is transmitted via the front differential 3 to the front axle shafts 2a and 21. , furthermore, it is transmitted to the front wheels 8a and 8t attached to the tip of the front wheel 88.
and 8 are actively driven, but this rotation is blocked by the transfer 4 and is not transmitted to the propeller shaft 5, so the propeller shaft 5, which has a large resistance, is almost at a standstill. On the other hand, in such a running state, the rear wheels 10a and lOl are driven in one direction by contact with the ground,
Along with this, the rear axle shirt L71, which is directly connected to the rear wheel 10, rotates in one direction between the rear wheel 10 and the rear wheel 10.
Rear wheel 10. The side portion 7a' of the side rear axle shaft 78 connected to the inner rear differential 6 rotates in the opposite direction with respect to the rear axle shaft foot. Therefore, in this state, the clutch 9 cannot be engaged; however, since the portions 71' and 7a'' of the rear axle shafts 7, 1 are separated by the clutch 9 in the disconnected state, reverse rotation of both is permitted.

Therefore, in the two-wheel drive state, the propeller shaft 5 should not be rotated (rear wheels '10a and 10I).

can be driven in the same direction.

Next, when switching from the two-wheel drive state (1) to the four-wheel drive state, the driver closes the four-wheel/two-wheel changeover switch 14. This switching is possible even while the vehicle is running. As a result, the vacuum switch valve VSV is opened, the negative pressure of the intake manifold 11 acts on the transfer 4, the transfer 4 is connected by the synchronizer mechanism, and the front differential 3
The rotation is transmitted to the propeller shaft 5, and the propeller shaft 5 starts rotating in synchronization with the traveling speed.

Due to the delay circuit, the Haki1-Musothiharub VSV2 is switched to the open state later than the switching of the Hakicomb switch valve VSV. This delay time is set to be slightly longer (for example, about 2 seconds as described above) than the time from when the 4-wheel to 2-wheel selector switch 14 is closed until the rotation of the propeller shaft 5 is completely stopped. When the filter comb switch valve VSV is switched to open as described above, the propeller shaft 5 has already begun to rotate in synchronization with the vehicle's traveling speed. Since the rotational speed of ' is equal to the rotational speed of the rear wheel 10. side part 7□'' and the rear axle shaft foot, the clutch 9 can be engaged at this point without causing any impact. .

If the clutch 9 is connected before the transfer 4, the part 9 of the rear axle shaft 73 will be connected, and such a connection is not possible with a dog-type clutch, and the clutch 9 will be subject to a non-uniform impact. is added and wears out in the 9th period. The propeller shaft 5 with large inertia and friction is connected to the rear axle shaft 711, and when the clutch 9 is engaged, not only the rear axle shaft 7a but also this stopped propeller shaft 5 must be instantaneously activated. The impact related to No. 9 will be even greater. On the other hand, in the embodiment 1-, as described above, the transfer 4 rotates the puller and I propeller shafts 5, and the portion 7a of the rear axle shaft 7a is rotated.
Since the clutch 9 is connected after the speeds 8' and 7a' are brought to the same speed, the above-mentioned impact on the clutch 9 does not occur at all, and smooth connection is possible.

In the first embodiment, a delay circuit is used to delay the engagement of the clutch 9, but if the clutch 9 is provided with a synchronizer mechanism so that engagement takes a certain amount of time, the delay circuit can be substantially delayed even without the delay circuit. can also be delayed. In this case vacuum switch valves VSV, and V
SV2 can be combined into one. Further, a delay means such as a damper or a heat shield may be provided in the middle of the pipe I2 connecting the vacuum switch valve VSV2 and the clutch 9 to delay the operation of the clutch 9. The mechanism may be such that it detects that the rotation of the clutch 5 has completely stopped and connects the clutch 9 at that point. ``In short, the present invention includes all means by which the clutch 9 can be connected substantially later than the transfer 4 is connected.

Further, in the above embodiment, the switching between two wheels and four wheels was achieved using the electric switch 14 and the delay circuit, but such a means for switching between four wheels and two wheels is not limited to this specific example, and may be applied to other machines. In addition, the means for operating the transfer 4 and clutch 9 are not limited to those using negative pressure as described above, but may also be performed by combining release wires, links, etc. It is also possible to operate these connecting means mechanically. As an example of such a mechanical clutch operating means, a clutch device or the like described in Japanese Utility Model Application Laid-open No. 58-140825 can be used.

In the embodiment described above, a mechanical engine type vehicle was taken as an example, but this is just an example and it is similarly applicable to a four-wheel drive vehicle having a longitudinally installed engine. Like the four-wheel drive vehicle described in Publication No. 58-44227, a transfer is provided between the front propeller shaft and the rear propeller shaft, and the front propeller shaft drives the front axle shaft via the front differential. ”
It goes without saying that the present invention is also applicable to a four-wheel drive system in which a rear axle shaft is driven by a propeller shaft via a rear differential.

As described above, the present invention connects the transfer and transmits the rotation of the engine to the front wheels and l&wheels via the front differential and rear differential when driving four-wheel drive, and cuts off the transfer when driving two-wheel drive to transmit only the front or rear wheels. In a four-wheel drive vehicle that actively drives the vehicle, a remotely controllable clutch is installed on the front axle shaft or rear axle shaft, and the four-wheel drive vehicle is installed in the vehicle interior.
a four-wheel drive device, wherein the four-wheel-to-two-wheel switching device is configured to engage the clutch later than the transfer engagement when switching from two-wheel drive to four-wheel drive. Since it is a car, it is possible to smoothly connect the clutch installed on the axle shaft when transitioning from a two-wheel drive state to a four-wheel drive state while driving, without applying unnecessary shock or load to the clutch. This makes it possible to switch between two and four wheels indoors.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an example of a power transmission mechanism of a four-wheel drive vehicle according to an embodiment of the present invention, and 2nd FA shows an example of a delay circuit that can be used in the embodiment (explanation of symbols) 1 ...Engine 2i, 2I, ...Front axle shaft 3...
Front differential 4... Transfer 5... Propeller shaft 6... Rear differential 7i, 7b... Rear axle shaft 8a, 8b...
・Front wheel 9...Clutch 10++, 10b...Rear wheel 11...Intake manifold vsv,, vsv2...Baki comb isochi I4...
・4-wheel-2-wheel selector switch D...Delay circuit. Applicant Daihatsu Motor Co., Ltd. Agent Patent Attorney Takeo Honjo

Claims (1)

[Claims] A 4-wheel drive vehicle that connects the transfer and transmits engine rotation to the front and rear wheels via the front differential and rear differential when in 4-wheel drive, and cuts off the transfer and actively drives only the front or rear wheels when in 2-wheel drive. , a remotely controllable clutch interposed in the front axle shaft or the rear axle shaft;
It has a four-wheel-to-two-wheel switching means disposed inside the vehicle, and the above-mentioned 4
A four-wheel drive vehicle characterized in that the clutch is engaged later than the transfer is engaged when the wheel-to-two-wheel switching means is switched from two-wheel drive to four-wheel drive.