JPH05213086A - Two wheel/four wheel drive changeover controller of transfer - Google Patents

Abstract

PURPOSE:To alarm that the switchover of a switch command to four wheel drive is forgotten and at the same time prevent the drive from becoming two wheel drive against an operater's will by making four wheel drive continue for the time being, when a high speed position is brought on from a low speed position where a four wheel drive condition is made forcedly, as high speed four wheel drive is desired. CONSTITUTION:The motive power of an input shaft 2 is transmitted to a main output shaft 3 in that condition at the high speed position of a coupling sleeve 9C, and by coupling a clutch 10, the motive power is also transmitted to a sub output shaft 4 properly, and the choice of high speed 2 wheel-4 wheel drive is possible. At the low speed position of the coupling sleeve 9C, the motive power of the input shaft 2 reaches the shaft 3 in deceleration, and this decelerated motive power also reaches the shaft 4 by combination between the coupling sleeve 9C and a clutch gear 14, and low speed four wheel drive is obtained. At the time of changeover to the high speed position from the low speed position, if a 4WD switch 18 is not ON, a controller 17 puts an alarm 16 ON during a setting time, and at the same time couples the clutch 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wheel / four-wheel drive switching control device for a vehicle transfer, which switches power from a main transmission between high speed and low speed and also switches between two-wheel and four-wheel drive.

[0002]

2. Description of the Related Art Conventionally, a transfer device includes an auxiliary transmission that constantly switches the power from a main transmission to an input shaft to a main output shaft and switches the auxiliary output shaft to the main output shaft. There is known a structure provided with a two-wheel / four-wheel drive switching mechanism that is capable of being driven by four wheels. A two-wheel / four-wheel drive switching mechanism in which a sub-output shaft is drive-coupled to a main output shaft is considered in consideration of switching responsiveness and reduction of switching shock.
As described in Japanese Patent No. 9352, it is advantageous to use a hydraulic or electromagnetic friction clutch instead of the dog clutch.

In this type of transfer device, when the operation system of the friction clutch constituting the two-wheel / four-wheel drive switching mechanism fails, the four-wheel drive state may not be obtained.

In order to solve this problem, it is usually unnecessary to drive two wheels at a low speed position of the auxiliary transmission. Therefore, at this low speed position, the four-wheel drive mode is forcibly set regardless of the switch command from the driver. It is conceivable that a dog clutch connecting the auxiliary output shaft to the main output shaft is provided in parallel with the friction clutch in association with switching to the low speed position. in this case,
Even if the friction clutch cannot be connected due to a malfunction of the operating system, it is possible to drive four wheels at a low speed position, and it is possible to avoid that the four wheels cannot be driven at all.

[0005]

However, in the case of the transfer device having such a countermeasure, when the low speed position is switched to the high speed position, the driving condition is the two-wheel driving condition according to the switch command from the driver or the two-wheel driving condition. The four-wheel drive state is set, and the driver mistakes the compulsory four-wheel drive state by the dog clutch until then for the switch command and changes the switch command from the two-wheel drive to the four-wheel drive. Forgetting this, when expecting high-speed four-wheel drive simply by switching from the low-speed position to the high-speed position, unlike this expectation, the high-speed two-wheel drive state is set, which makes the driver feel uncomfortable. The present invention eliminates the above-mentioned sense of discomfort by warning such an operation forgetting during the set time after the transfer device is switched from the low speed position to the high speed position and keeping the four-wheel drive state for a certain time regardless of the switch command. The purpose is to

[0006]

To this end, the present invention is directed to an auxiliary transmission, in which the power to the input shaft is switched between high speed and low speed and transmitted to the main output shaft, and the auxiliary output shaft is drive-coupled to the main output shaft as appropriate. A vehicle having a two-wheel / four-wheel drive switching mechanism, which has a friction clutch as a main element and appropriately couples the friction clutch according to a switch command from a driver, and forcibly enters a four-wheel drive state at a low speed position of the auxiliary transmission. In the transfer device, when the auxiliary transmission is switched from the low speed position to the high speed position, the friction clutch is engaged and the four-wheel drive state is set during the set time even if the switch command indicates the two-wheel drive. Along with this, a 4WD switching operation forgetting warning means for issuing a warning to the driver is provided.

[0007]

The sub-transmission switches the power to the input shaft between high speed and low speed in response to the high / low speed switching operation, transmits the power to the main output shaft, and drives the two wheels that should always be driven, and the two-wheel-four-wheel drive. The switching mechanism appropriately drives and connects the auxiliary output shaft to the main output shaft by means of a friction clutch in response to a switch command from the driver, and brings the other two wheels into a four-wheel drive state in which the auxiliary output shaft can also drive. It should be noted that at the low speed position of the auxiliary transmission, the four-wheel drive state is forcibly set regardless of the switch command.

By the way, at the time of switching the auxiliary transmission from the low speed position to the high speed position, even if the switch command indicates the two-wheel drive, the 4WD switching operation forgetting alarm means is coupled to the friction clutch during the set time, and the four-wheel operation is performed. It puts the vehicle in a driving state and issues a warning to the driver. Therefore, if the driver desires four-wheel drive, the switch command can be changed to a four-wheel drive command during this period to continue high-speed four-wheel drive, and the low-speed four-wheel drive is switched to the high-speed four-wheel drive. It is possible to avoid a sense of discomfort due to the high-speed two-wheel drive state, even though a switching operation from the low speed position to the high speed position is performed in hope of switching.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a transfer device according to an embodiment of the present invention. Reference numeral 1 denotes a transfer case, and an input shaft 2 and a main output shaft 3 are arranged in a coaxial butting relationship in the transfer case 1 so as to be relatively rotatable. At the same time, the auxiliary output shaft 4 is supported by being arranged in parallel with these shafts. The input shaft 2 is connected to an output shaft 5 of a main transmission (not shown), the main output shaft 3 is connected to two differential gears of the vehicle which should be driven constantly, and the auxiliary output shaft 4 is to be driven appropriately of the vehicle. Connect to the wheel differential gear.

An auxiliary transmission 6 and a two-wheel / four-wheel drive switching mechanism 7 are provided on the input shaft 2 and the main output shaft 3. The auxiliary transmission 6 is a simple planetary gear set including a sun gear 8S formed on the input shaft 2, an internal ring gear 8R fixed in the transfer case 1, and a carrier 8C rotatably supporting a pinion 8P meshing with these. 8 is a main constituent element, and the following high / low speed switching mechanism 9 is coaxially provided on the constituent element.

The high / low speed switching mechanism 9 has a hub 9B connected to the main output shaft 3, a coupling sleeve 9C slidably engaged with the hub 9B, and this coupling sleeve is shown by a solid line in the upper half of the figure. A clutch gear 9H integrally formed with the input shaft 2 so that the internal teeth are engaged at the high speed position H;
The coupling sleeve 9C is composed of a clutch gear 9L provided on the carrier 8C so that its outer teeth are meshed at a low speed position L shown in the lower half of the figure.

The two-wheel / four-wheel drive switching mechanism 7 has a friction clutch 10 as a main constituent element, and the clutch hub 10 thereof.
The H is rotatably supported on the main output shaft 3, and is rotatably connected to the sub output shaft 4 through the sprocket 11, the chain 12, and the sprocket 13 in a winding relationship. The clutch drum 10D of the friction clutch 10 is drivingly coupled to the main output shaft 3, and the piston 10P is fitted in the drum 10D. The friction clutch 10 operates between the clutch hub 10H and the clutch drum 10D when the piston 10P is hydraulically operated.
Therefore, the main output shaft 3 and the sub output shaft 4 are drive-coupled to each other, so that power can be taken out not only from the main output shaft 3 but also from the sub output shaft 4 as appropriate.

Further, in this embodiment, a clutch gear 14 is connected to the clutch hub 10H of the friction clutch 10 side by side with the sprocket 11, and the clutch gear meshes with the coupling sleeve 9C at a low speed position L shown in the lower half of the figure. The arrangement and diameter are set as follows. Therefore, the coupling sleeve 9C and the clutch gear 14 form a dog clutch forcibly connecting the main output shaft 3 and the sub output shaft 4 at the low speed position.

The coupling sleeve 9C of the high / low speed switching mechanism 9 is to be manually operated by the driver with a shift lever, and the friction clutch 10 of the two-wheel / four-wheel drive switching mechanism 7 is assumed.
When the solenoid valve 15 is turned on, the hydraulic pressure is supplied from now on to connect the solenoid valve 15. Then, the controller 17 controls the ON / OFF of the solenoid valve 15 together with the ON / OFF of the alarm device 16, so that the controller sends a switch command from the 4WD switch 18 which is turned on by the driver when four-wheel drive is desired. And a signal from the high speed switch 19 which is turned on at the high speed position H of the coupling sleeve 9C and a signal from the low speed switch 20 which is turned on at the low speed position of the coupling sleeve 9C.

The controller 17 is a 4WD according to the present invention.
It serves as a switching operation forgetting warning means, and executes the control program of FIG.
Wheel drive switching control, and two wheels that the present invention aims at-4
Wheel drive switching control shall be realized. That is, first, in steps 31 and 32, the coupling sleeve 9C (auxiliary transmission 6) is indicated by a chain double-dashed line in the upper half of FIG. Check if it is in neutral position N. At the neutral position N, in step 33, the hydraulic pressure is supplied to the friction clutch 10 by turning on the solenoid valve 15 to connect the hydraulic pressure, and the sub output shaft 4 is drivingly connected to the main output shaft 3. To explain the power transmission path, the power from the main transmission output shaft 5 is directly input to the sub transmission input shaft 2 on the one hand, and is decelerated by the planetary gear set 8 on the other hand to reach the carrier 8C. Then, when the coupling sleeve 9C is in the neutral position N, the coupling sleeve does not mesh with any of the clutch gears 9H and 9L, and the power is not transmitted to the main output shaft 3. Of course,
Since no power is transmitted to the sub output shaft 4 drivingly coupled to the main output shaft by the friction clutch 10 as described above, all the wheels are not driven.

Here, when the coupling sleeve 9C is set to the low speed position L, the coupling sleeve meshes with the clutch gear 9L and the carrier 8C is decelerated and driven.
The main output shaft 3 is connected to and the driving wheels are constantly driven at low speed. At this time, the low speed position L is determined in step 31 of FIG. 2, and the control is terminated as it is. However, at this low speed position, the coupling sleeve 9C also meshes with the clutch gear 14 and regardless of the friction clutch 10. The main output shaft 3 and the sub output shaft 4 are forcibly connected. Therefore, the friction clutch 1
Even if the operating system of 0 fails and the operating hydraulic pressure does not occur, the engagement of the coupling sleeve 9C and the clutch gear 14 can ensure the four-wheel drive state at the minimum low speed position, and the four-wheel drive is completely impossible. It is possible to avoid the situation.

When the coupling sleeve 9C is moved to the high speed position H, the coupling sleeve slides on the hub 9B and meshes with the clutch gear 9H. Input shaft 2 at this time
To the main output shaft 3 via the clutch gear 9H and the hub 9B as it is, and the constant drive wheels related to this output shaft are driven at high speed. This high speed position is determined in step 32 of FIG. 2, and at this time, the control reaches step 34, where 4 W is set.
It is checked whether the D switch 18 is ON, that is, whether the driver desires four-wheel drive. If desired, in step 35, the hydraulic pressure is supplied to the friction clutch 10 by turning on the solenoid valve 15 to connect the hydraulic pressure (drive connection of the auxiliary output shaft 4 to the main output shaft), and the auxiliary output shaft 4 is engaged. Achieve the required four-wheel drive state in which the other two wheels are driven at high speed.

If it is determined in step 34 that the 4WD switch 18 is not turned on, the timer T is reset to 0 in step 36 to measure the elapsed time from switching to the high speed position. Then, in steps 37 and 38, the driver operates the 4WD switch 18 until the elapsed time T reaches the set time Ts (for example, 10 seconds).
Check whether or not was turned on. 4WD switch O
If N is not present, the driver may have forgotten the operation. Therefore, in step 39, the solenoid valve 15 is turned on for the time being to connect the friction clutch 10 with the supply of operating hydraulic pressure to bring it into the four-wheel drive state. , O alarm 16
N to warn the driver whether he or she forgets to operate the 4WD switch 18. When the driver turns on the 4WD switch 18 in response to this alarm, the control proceeds to step 40 at this point, and the alarm device 1 is activated while continuing the engagement of the friction clutch 10.
Turn off 6.

If the 4WD switch 18 is not turned on even after the set time Ts has passed from the switching to the high speed position, 4
Since he has not forgotten to operate the WD switch 18 and does not desire four-wheel drive, the control proceeds to step 41, where the solenoid valve 15 is turned off to release the friction clutch 10 and switch to two-wheel drive as requested. The alarm device 16 is turned off.

As described above, at the time of switching from the low speed position to the high speed position, the same four-wheel drive state as that at the time of the low speed position is temporarily maintained during the set time Ts at the beginning of the switching, and the operation of the 4WD switch 18 is not forgotten. Therefore, it is possible to avoid a situation in which the driver feels uncomfortable due to switching from low-speed four-wheel drive to unintended high-speed two-wheel drive due to forgetting this operation.

[0021]

As described above, according to the two-wheel / four-wheel drive switching control device of the present invention, when the auxiliary transmission is switched from the low speed position to the high speed position, the switch command from the driver is transmitted to the two wheels. Even if driving is indicated, during the set time, the friction clutch is engaged to bring the vehicle to the four-wheel drive state, and the driver is alerted. Therefore, if the driver wants four-wheel drive, During this time, the switch command can be changed to a four-wheel drive command to switch from low-speed running to high-speed running while maintaining four-wheel drive. It is possible to avoid a situation in which the driver is uncomfortable due to a high speed two-wheel drive state due to forgetting to switch the switch command despite the switching operation to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a vehicle transfer showing an embodiment of a two-wheel / four-wheel drive switching control device of the present invention.

FIG. 2 is a flowchart showing a program for two-wheel / four-wheel drive switching control executed by the controller of the example.

[Explanation of symbols]

 1 transfer case 2 input shaft 3 main output shaft 4 auxiliary output shaft 5 main transmission output shaft 6 auxiliary transmission 7 two-wheel-four-wheel drive switching mechanism 8 simple planetary gear set 9 high / low speed switching mechanism 10 friction clutch 11 sprocket 12 chain 13 Sprocket 14 Clutch gear 15 Solenoid valve 16 Alarm device 17 Controller (Alarm means for forgetting 4WD switching operation) 18 4WD switch 19 High speed switch 20 Low speed switch

Claims (1)

[Claims] 1. A sub-transmission that transmits power to an input shaft to a main output shaft by switching between high speed and low speed, and a friction clutch that drivably connects the sub output shaft to the main output shaft as a main element. Connect properly according to switch command from 2
In a transfer device for a vehicle, which has a four-wheel / four-wheel drive switching mechanism and is forced to be in a four-wheel drive state at a low speed position of the auxiliary transmission, the switch is used when the auxiliary transmission is switched from a low speed position to a high speed position. Even if the command indicates two-wheel drive, the friction clutch is engaged for four-wheel drive during the set time, and a 4WD switching operation forgetting alarm means for issuing an alarm to the driver is provided. A transfer two-wheel / four-wheel drive switching control device.