JP3124606B2 - Vehicle transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer apparatus for a vehicle that switches between high and low speeds of power from a main transmission and performs two-wheel / four-wheel drive switching.

[0002]

2. Description of the Related Art Conventionally, a transfer device is provided with a sub-transmission, which switches between high speed and low speed power from a main transmission to an input shaft and constantly transmits the power to a main output shaft. There is known a configuration provided with a two-wheel / four-wheel drive switching mechanism that enables driving and four-wheel driving by coupling.
And a two-wheel drive for appropriately coupling the sub output shaft to the main output shaft.
The four-wheel drive switching mechanism is used in consideration of switching responsiveness and reduction of switching shock.
It is advantageous to use a hydraulic or electromagnetic friction clutch in place of the dog clutch as described in -39352.

In this type of transfer device, when the operating system of the friction clutch constituting the two-wheel / four-wheel drive switching mechanism fails, the clutch cannot be engaged,
The four-wheel drive state can no longer be selected.

In order to solve this problem, two-wheel drive is not normally required at the low speed position of the auxiliary transmission. Therefore, at the low speed position, the four-wheel drive state is forcibly changed regardless of the switch command from the driver. In order to achieve this, it is conceivable to provide a dog clutch that connects the sub output shaft to the main output shaft in parallel with the friction clutch in conjunction with switching to the low speed position. in this case,
Even if the friction clutch is disengaged due to a failure in the operation system, four-wheel drive can be performed at the low-speed position, and the situation in which four-wheel drive cannot be performed can be eliminated.

[0005]

However, in the case of a transfer device in which such measures are taken, the driving state changes during the L → H shift from the low speed position to the high speed position in response to the switch command from the driver during the shifting operation. The two-wheel drive state or the four-wheel drive state is set accordingly, and if the driver's switch command is the two-wheel drive, the two-wheel drive state is changed from the forcible four-wheel drive state by the dog clutch during the shift operation. The driver may be switched to the driving state and be confused by the driver performing the gear shifting operation.

According to the present invention, when switching from the low-speed position to the high-speed position, the four-wheel drive state is maintained by the friction clutch until the operation is completed, regardless of the switch command from the driver. The aim is to eliminate the problem.

[0007]

SUMMARY OF THE INVENTION To this end, a vehicle transfer apparatus according to the present invention comprises a sub-transmission that transmits power to an input shaft to a main output shaft by switching between high and low speeds by a meshing clutch, and a sub-output shaft. A two-wheel / four-wheel drive switching mechanism for appropriately coupling the friction clutch to the main output shaft as a main element in accordance with a switch command from a driver, and engaging the clutch at a low speed position of the meshing clutch. In the vehicle transfer device, the clutch is also meshed and engaged with the sub-output shaft-side member to drive-connect the sub-output shaft to the main output shaft so as to forcibly enter the four-wheel drive state at the low-speed position. While the main output shaft and the sub-output shaft side member are integrally rotated by the meshing coupling of the meshing clutch, the rotation of the main output shaft and the member of the auxiliary output shaft is also possible by the coupling of the friction clutch. Configured to be rotated, when switching to the high speed position from the low speed position of the dog clutch,
Until this switching is completed, the switch command is set to 2
Even if wheel drive is indicated, the friction clutch is
An L → H shift four-wheel drive holding means for holding a wheel drive state is provided.

[0008]

The sub-transmission switches the power from the input shaft between high and low speeds according to the high and low speed positions of the meshing clutch responding to the high and low speed switching operation, and transmits this to the main output shaft to drive the two wheels to be constantly driven. The two-wheel / four-wheel drive switching mechanism drives and connects the auxiliary output shaft to the main output shaft appropriately by a friction clutch in response to a switch command from the driver, and can drive the other two wheels by the auxiliary output shaft. A four-wheel drive state is set. In the low-speed position of the meshing clutch, the meshing clutch meshes with and engages with the sub-output shaft side member to drive-couple the sub-output shaft to the main output shaft, thereby forcibly entering the four-wheel drive state regardless of the switch command. Is done.

By the way, while the main output shaft and the sub-output shaft side member are integrally rotated by the meshing coupling of the meshing clutch, they can be integrally rotated by the coupling of the friction clutch. When switching from the high-speed position to the high-speed position, even if the switch command indicates two-wheel drive, the four-wheel drive holding means for L → H shift engages the friction clutch until the end of the switch and the four-wheel drive up to that point. Keep driving state. Therefore, even if the switch command at the time of switching from the low-speed position to the high-speed position indicates two-wheel drive,
Until the switching is completed, the same four-wheel drive state as before is maintained. During this switching operation, the operation is switched from the forced four-wheel drive state at low speed to the two-wheel drive state, and the operation during the shifting operation is performed. Without embarrassing others
It is informative.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a transfer apparatus according to an embodiment of the present invention. Reference numeral 1 denotes a transfer case, in which an input shaft 2 and a main output shaft 3 are arranged in a coaxial butt relationship in a transfer case 1 and are rotatably supported. At the same time, the auxiliary output shaft 4 is mounted in parallel with the shafts 2 and 3. 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 that are to be driven at all times of the vehicle, and the sub output shaft 4 is to be driven appropriately for the vehicle. Connect to the differential gear of the wheel.

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 the sun gear 8S. 8 is a main component, and a high / low speed switching mechanism 9 of the following mesh type is provided coaxially with the main component.

The high / low speed switching mechanism 9 includes a hub 9B coupled to the main output shaft 3, a coupling sleeve 9C slidably engaged with the hub 9B, and the coupling sleeve 9C which is shown by a solid line in the upper half in the figure. The clutch gear 9H for high-speed selection integrally formed with the input shaft 2 so that the internal teeth are meshed with the internal teeth at the high-speed position H, and the external teeth are meshed with the coupling sleeve 9C at the low-speed position L shown in the lower half of the figure. Carrier 8C
And the low-speed selection clutch gear 9L provided in the above.

The two-wheel / four-wheel drive switching mechanism 7 includes a friction clutch 10 as a main component,
H is rotatably supported on the main output shaft 3, and is driven and connected to the sub output shaft 4 via the sprocket 11, the chain 12, and the sprocket 13 in a winding transmission relationship. A clutch drum 10D of the friction clutch 10 is drivingly connected to the main output shaft 3, and a piston 10P is fitted in the drum 10D. When the hydraulic pressure of the piston 10P is actuated, the friction clutch 10 moves between the clutch hub 10H and the clutch drum 10D.
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.

In this embodiment, a four-wheel drive clutch gear 14, which is a member on the side of the auxiliary output shaft, is connected on the clutch hub 10H of the friction clutch 10 side by side with the sprocket 11. The clutch gear 14 has a coupling sleeve 9C. The arrangement and diameter are such that they mesh at the low speed position L shown in the lower half of the figure. Therefore, the coupling sleeve 9C and the clutch gear 14 constitute a dog clutch forcibly connecting the main output shaft 3 and the sub output shaft 4 at the low speed position L.

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 provided.
It is assumed that when the hydraulic pressure generating motor device 15 is turned on, the operating hydraulic pressure is supplied from now on to connect the hydraulic pressure generating motor device 15. Then, ON / OFF of the motor device 15 is changed to ON / O of the 4WD lamp 16.
The controller 17 is controlled together with the FF by a controller 17. For this reason, a switch command from a 4WD switch 18 which is turned on when the driver desires four-wheel drive is input to the controller 17, and the high-speed position H of the coupling sleeve 9 C is inputted.
And a clutch pressure switch which is turned on by detecting a signal from a high speed switch 19 turned on at a low speed position L of the coupling sleeve 9C, a signal from a low speed switch 20 turned on at a low speed position L, and an operating oil pressure from the motor device 15 to the friction clutch 10. Signals from the control unit 21 are input.

The operation of the above embodiment will now be described. The power from the main transmission output shaft 5 is directly input to the auxiliary transmission input shaft 2 on the one hand, and is reduced by the planetary gear set 8 to the carrier 8C on the other hand. When the coupling sleeve 9C is at the neutral position N shown by a two-dot chain line in the upper half of FIG.
H and 9L do not mesh with each other, and power is not transmitted to the main output shaft 3. Of course, no power is transmitted to the sub output shaft 4, so that all wheels are not driven.

Here, when the coupling sleeve 9C is set to the H position, the coupling sleeve 9C is connected to the hub 9B.
Sliding upward engages the clutch gear 9H. At this time, the power from the input shaft 2 directly passes through the clutch gear 9H and the hub 9B to reach the main output shaft 3, and drives the constantly driven wheels related to the main output shaft 3 at high speed. And friction clutch 1
If the friction clutch 10 is not engaged by the hydraulic operation of the piston 10P (when the motor device 15 is OFF) and the friction clutch 10 is engaged by the hydraulic operation of the piston 10P (when the motor device 15 is ON), the main operation is performed. Output shaft 3
The sub-output shaft 4 is coupled to the sub-output shaft 4 so that power is also output from the sub-output shaft 4, and a high-speed four-wheel drive state in which the other two wheels are driven at a high speed is obtained.

When the coupling sleeve 9C is set to the L position, the coupling sleeve 9C is
The main output shaft 3 is coupled to the carrier 8C that is being driven at a reduced speed, and the driving wheels are constantly driven at a low speed. By the way, at this low speed position L, the coupling sleeve 9C also meshes with the clutch gear 14 to forcibly drive-connect the main output shaft 3 and the sub output shaft 4 regardless of the friction clutch 10. Therefore, even if the operating system of the friction clutch 10 fails and no operating hydraulic pressure is generated, the four-wheel drive state can be secured at the minimum low-speed position by the engagement of the coupling sleeve 9C and the clutch gear 14. It is possible to avoid a situation in which driving becomes impossible.

The controller 17 is configured as follows.
The four-wheel drive holding means for speed change is used, and the control program shown in FIGS. It is assumed that wheel drive switching control is realized.

FIG. 2A shows a main routine. First, various initial settings are made in step 31, and in step 32
The signal from the clutch pressure switch 21 and the high-speed switch 1
9 and the signal from the low-speed switch 20 are read. In the next step 33, if the friction clutch 10 is engaged based on the determination result based on the signal from the clutch pressure switch 21, and if the frictional clutch 10 is connected based on the determination result based on the signal from the low speed switch 20, the low-speed driving is forcibly switched to the four-wheel drive state. If the position is L, the 4WD lamp 16 is turned on to display the four-wheel drive state, and otherwise, the 4WD lamp 16 is turned off.

In step 34, the signal from the 4WD switch 18 is read, and in the next step 35, it is checked whether the engagement and disengagement of the friction clutch 10 (the signal of the clutch pressure switch 21) matches this 4WD switch command. I do. If they do not match, in step 36, the friction clutch 10 is engaged or disengaged by switching the motor device 15 on and off, and the 4WD switch 18
Is switched to the four-wheel drive state or the two-wheel drive state so as to match the instruction from the driver via the. However, the low speed position L
As described above, since the four-wheel drive state is established irrespective of the friction clutch 10, the friction clutch 10 is released regardless of the command from the 4WD switch 18.

While it is determined in step 35 that the driving state matching the command from the driver by the 4WD switch 18 has been achieved, in step 37 each high / low speed switching subroutine is executed. FIG. 2B shows a subroutine for switching from the low-speed position L to the high-speed position H related to the present invention. That is, when it is determined in step 41 that the low-speed switch 20 is turned on and the low-speed selection is being performed, the control is terminated and the four-wheel drive control is performed in step 36, but when switching from the low-speed position L to the high-speed position H is performed. Is selected in response to the turning-off of the low-speed switch 20, in step 42, the operating oil pressure is supplied to the friction clutch 10 by turning on the motor device 15, and this is temporarily connected. The temporary engagement of the friction clutch 10 is continued until it is determined in step 43 that the high-speed switch 19 has been turned on, that is, until the switching in which the coupling sleeve 9C is at the high-speed position H is completed.

During the shifting operation from the low speed position L to the high speed position H due to the temporary engagement of the friction clutch 10, 4WD
Regardless of the switch command from the switch 18, the same four-wheel drive state as in the previous low-speed position is maintained, and the driver switches from the four-wheel drive state to the two-wheel drive state during the speed change operation, and It can eliminate the embarrassment.

After the shift operation is completed, at step 44, 4W
It is checked whether or not the D switch 18 is ON, and according to the result, if ON, the control is terminated as it is, so that the friction clutch 10 is continuously connected as requested to continue the four-wheel drive state, and if OFF, at step 45 When the motor device 15 is turned off, the hydraulic pressure applied to the friction clutch 10 is lost and the clutch 10 is released, thereby switching to the two-wheel drive state as required.

[0025]

As described above, according to the transfer apparatus of the present invention, when the auxiliary transmission is switched from the low speed position to the high speed position, even if the switch command from the driver indicates two-wheel drive, During the switching operation, the friction clutch is engaged to maintain the same four-wheel drive state as that at the time of the previous low-speed selection, so that the driver switches from four-wheel drive to two-wheel drive during the switching operation, and Can be avoided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of an embodiment of a vehicle transfer device according to the present invention.

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transfer case 2 Input shaft 3 Main output shaft 4 Sub output shaft 5 Main transmission output shaft 6 Sub transmission 7 Two-wheel / four-wheel drive switching mechanism 8 Simple planetary gear set 9 High / low speed switching mechanism (mesh clutch) 10 Friction clutch 11 Sprocket 12 Chain 13 Sprocket 14 Clutch gear (sub output shaft side member) 15 Hydraulic pressure generating motor device 16 4WD lamp 17 Controller (4-wheel drive holding means for L → H shift) 18 4WD switch 19 High speed switch 20 Low speed switch 21 Clutch Pressure switch

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-267031 (JP, A) JP-A-64-1538 (JP, A) JP-A-56-39352 (JP, A) JP-A-3-3 277853 (JP, A) Japanese Utility Model Hei 2-18726 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60K 23/00-23/08 B60K 17/28-17/36

Claims (1)

(57) [Claims] The friction clutch includes a sub-transmission that transfers power to an input shaft to a main output shaft by switching between high and low speeds by a meshing clutch, and a friction clutch that drives and connects the sub-output shaft to the main output shaft as appropriate. And a two-wheel / four-wheel drive switching mechanism that appropriately couples in accordance with a switch command from a driver. A drive output coupling to the main output shaft to forcibly enter the four-wheel drive state at the low-speed position, wherein the engagement clutch is disposed between the main output shaft and the sub output shaft side member. While being integrally rotated by the meshing connection, the clutch can be integrally rotated by the coupling of the friction clutch. At the time of switching to the rear-wheel drive, the friction clutch is engaged to maintain the four-wheel drive state until the switch is completed, even if the switch command indicates two-wheel drive. A transfer device for a vehicle, comprising a holding means.