JP2000190754A - Automotive power transmission - Google Patents

Abstract

(57) [Summary] The present invention can reduce the size of the switching motor unit by eliminating the waiting mechanism of the two-wheel / four-wheel switching device from within the switching motor unit, and reduce the cost. Further, it is another object of the present invention to prevent an excessive switching load from being applied to the transfer by the control means. For this purpose, there is provided a transfer for transmitting a driving force from a transmission connected to an engine of a four-wheel drive vehicle to front and rear wheels, and a vehicle that switches a drive state of the four-wheel drive vehicle to a two-wheel or four-wheel drive state In the power transmission device, a transfer motor unit for a two-wheel / four-wheel switching device is provided in the transfer, a waiting mechanism is provided outside the switching motor unit, a transfer motor is provided in the switching motor unit, and front and rear wheels are provided. An axle motor is provided for one of the axles, and a control means for switching control between the transfer motor and the axle motor is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for a motor vehicle, and more particularly, to a reduction in size of a switching motor unit by eliminating a waiting mechanism of a two-wheel / four-wheel switching device from within the switching motor unit. In addition, the present invention relates to a power transmission device for an automobile that can reduce the cost and that can control switching between a transfer motor and an axle motor by a control means to prevent an excessive switching load from being applied to the transfer.

[0002]

2. Description of the Related Art An automobile is provided with a transmission for shifting a driving force from a mounted engine to a desired shift state.
Some transmissions have a transfer that switches between a two-wheel drive state and a four-wheel drive state.

In this transfer, the driving state of a four-wheel drive vehicle is switched to a two-wheel drive state or a four-wheel drive state by a two-wheel / four-wheel switching device when a transfer shift lever is operated.

[0004] An example of the power transmission device for an automobile is disclosed in JP-A-9-104256. The power transmission device disclosed in this publication includes a plurality of engagement members between a driving member fixed to an input shaft and a driven member fixed to an output shaft, and an engagement operation position of each engagement member with respect to the driving member and the driven member. Incorporating a clutch consisting of a retainer for moving the input shaft, a lock means is provided on the input shaft to be detachably coupled to the driven member by remote control from the outside, and the lock means is provided with:
A slider that rotates integrally with the input shaft and is movable in the axial direction, a case located outside the slider, and a rotation transmission mechanism that transmits the rotation of the slider to the case by frictional force, and is a case of a lock unit. And a driven member, and a slider and a driven member, each of which is provided with a pair of meshing portions which are detachably coupled to each other, a rotation synchronization mechanism is provided between the driven member and the case, and a two-wheel drive mode and a four-wheel drive mode are operated by moving the slider. Switching between the traveling lock mode and the 4WD traveling overrunning mode is performed.

[0005] Further, there is one disclosed in Japanese Patent Application Laid-Open No. 9-164855. The power transmission device disclosed in this publication separates a drive shaft connecting a differential and wheels of a vehicle in an axial direction, and provides a separation mechanism with a clutch mechanism that transmits and shuts off torque by remote operation from outside,
Between the driving member provided on the differential side of the clutch mechanism and the driven member provided on the wheel side, there is provided a synchronous friction mechanism for synchronizing the rotation of the driving member and the driven member when the driven member meshes, and the synchronous friction mechanism comprises: It consists of an annular taper cone attached to the driven member and a taper cone attached to the drive member so as to press against the inner periphery of the taper cone. Synchronized, two-wheel drive and four-wheel drive are instantaneously switched by remote control.

[0006]

In a conventional automobile, for example, a full-time or part-time four-wheel drive vehicle, a transfer that can be switched between a two-wheel drive state and a four-wheel drive state during traveling is provided. A transfer shift lever for mechanically switching between a two-wheel drive state and a four-wheel drive state, and a two-wheel drive state and a four-wheel drive state using an engine negative pressure or a rotational force of a motor. There is something to switch.

However, in the case of a method of mechanically switching by a transfer shift lever, it is necessary to set the operating force to an appropriate value or to increase the synchro so as to withstand the operation under a high load.

Further, in the negative pressure type, there is a disadvantage that the variation in pressure is large and the capacity of the actuator is increased, which is disadvantageous in practical use.

Further, in the measure utilizing the rotational force of the motor, as shown in FIG. 6, a waiting mechanism 330 is provided between the motor 346 and the transfer shift fork 338. The waiting mechanism 330 prevents the switching operation when the rotation difference between the front and rear wheels is large.

However, when the motor 346 becomes large,
If there is a defect in the waiting mechanism 338, there is a disadvantage that the switching operation cannot be performed.

[0011]

Therefore, in order to eliminate the above-mentioned disadvantages, the present invention is provided with a transmission connected to an engine mounted on a four-wheel drive vehicle, and the driving force from this transmission is transmitted to front and rear wheels. A power transmission device for an automobile that switches a driving state of the four-wheel drive vehicle to a two-wheel drive state or a four-wheel drive state by providing a transfer motor unit for a two-wheel / four-wheel switching device to the transfer. And a waiting mechanism of the two-wheel / four-wheel switching device is removed from the switching motor unit and provided, a transfer motor is provided in the switching motor unit, and an axle motor is provided on one of the front and rear wheels. Control means for switching control between a transfer motor and an axle motor is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION
The control means controls the transfer motor and the axle motor to switch between the two-wheel drive state and the four-wheel drive state, thereby preventing an excessive switching load from being applied to the transfer.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 9 show an embodiment of the present invention. 1 and 2, 2 is a four-wheel drive vehicle, 4 is a front wheel, 6 is a rear wheel, 8 is a transmission, and 10 is a transfer.

The four-wheel drive vehicle 2 has an engine (not shown) mounted thereon, and a transmission 8 is connected to the engine.

As shown in FIG. 2, the transmission 8 supports an input shaft 14, a counter shaft 16, and an output shaft 18 in a transmission case 12.

The input shaft 14 and the output shaft 18 are connected so as to have the same center of rotation, and a counter shaft 16 is provided in parallel with the input shaft 14 and the output shaft 18.
A plurality of transmission gear trains 20 are provided between the shafts 14 to 18. The plurality of speed change gear trains 20 include, for example, an input gear train (not shown), first to fourth gear trains, and a reverse gear train.

Various switching mechanisms such as a first-speed / second-speed switching mechanism and a third-speed / four-speed switching mechanism (not shown) are provided between the plurality of transmission gear trains.

Further, the transmission case 12 of the transmission 8
A front case 12-1 surrounding the input side of the input shaft 14, a center case 12-2 surrounding the intermediate portion of the input shaft 14, and a rear case 12-3 surrounding the output side of the input shaft 14. The transfer case 22 of the transfer 10 is mounted on the rear case 12-3 of the transmission case 12.

The two-wheel / four-wheel switching device 24 is configured as shown in FIG.
As shown in FIG. 3, the vehicle includes a two-wheel / four-wheel switching mechanism 26 provided inside the transfer case 22, a switching motor unit 28 provided outside the transfer case 22, and a waiting mechanism 30.

As shown in FIG. 3, the two-wheel / four-wheel switching mechanism 26 includes an output shaft sprocket 32 of the output shaft 18, a front drive sprocket 34 rotatably disposed on the outer periphery of the output shaft 18, and an output shaft. 2 for intermittently engaging the shaft sprocket 32 with the front drive sprocket 34
A four-wheel / four-wheel switching sleeve 36 and a transfer shift fork 38 engaged with the two-wheel / four-wheel switching sleeve 36
And two wheels and four wheels provided with a transfer shift fork 38
The driving force transmitted to the front drive sprocket 34 has a wheel switching rod 40, and the driving force transmitted to the front drive sprocket 34 is distributed to the distribution shaft 42 of the transfer 10 disposed in parallel with each of the input shaft 14, the counter shaft 16 and the output shaft 18. Through a transmission means 44 such as a chain.

The two-wheel / four-wheel switching rod 40 is disposed in parallel with each of the input shaft 14, the counter shaft 16, and the output shaft 18.

At this time, the waiting mechanism 30 of the two-wheel / four-wheel switching device 24 is removed from the switching motor unit 28 and provided, and a transfer motor 46 is provided in the switching motor unit 28 so that any one of the front and rear wheels is provided. On the other hand, for example, an axle motor 50 is provided on the axle 48 of the front wheel 4 and a control means (also referred to as a “controller”) 52 for controlling switching between the transfer motor 46 and the axle motor 50 is provided.

More specifically, as shown in FIGS. 1 to 3, a switching motor unit 28 of the two-wheel / four-wheel switching device 24 is provided near the transfer 10, and this switching motor unit 2 is provided.
8 and a transfer motor 46 is provided in the front wheel 4 of the four-wheel drive vehicle 2.
0, the transfer motor 46 and the axle motor 5
0 is connected to the control means 52 and provided.

The control means 52 controls the transfer motor 46 when switching from the two-wheel drive state to the four-wheel drive state.
Is operated to lock the transfer 10,
The axle motor 50 is operated to control the axle 48 to be locked.

As shown in FIG. 3, the waiting mechanism 30, which is removed from the switching motor unit 28, is provided on the two-wheel / four-wheel switching rod 40 in the transfer 10, and the transfer shift forks 38, 2 Circle 4
Between the two-wheel / four-wheel switching rod 40, that is, in the middle of the power transmission path of the power transmitted from the two-wheel / four-wheel switching rod 40 to the transfer shift fork 38,
The function is performed at the time of switching to the wheel drive state.

Further, the waiting mechanism 30 comprises a coiled spring 54, and the two wheels 4
It is disposed between a transfer shift fork 38 provided on the wheel switching rod 40 and the transmission case 12.

At this time, the spring 54 urges the transfer shift fork 38 away from the transmission case 12.

In the two-wheel / four-wheel switching device 24, as shown in FIG. 3, an input pinion gear 56 is provided separately from the switching motor unit 28 in the transfer 10, and a motor output shaft 58 of the transfer motor 46 is provided. And a pinion gear 56 on the transfer 10 side.

As shown in FIG. 3, a rack 60 is provided at an end of the two-wheel / four-wheel switching rod 40, and the pinion gear 56 is provided in mesh with the rack 60.

Reference numeral 62 denotes a front differential, 64 denotes a front propeller shaft, 66 denotes a rear differential, 68 denotes a rear propeller shaft, and 70 denotes a power window regulator.

Next, the operation will be described with reference to the flowchart.

From the two-wheel drive (2WD) state to the four-wheel drive (4
At the time of switching to the WD) state, as shown in FIG. 4, when a switching instruction (100) is issued, it is determined (102) whether or not the vehicle speed is 85 km / h or less.

If the determination (102) is NO, that is, if the vehicle speed exceeds 85 km / h, the vehicle speed becomes 85 km / h.
h (see FIG. 4), and the determination (102) is repeated.

If the determination (102) is YES, a determination (104) is made as to whether the transfer (T / F) operation is OK. If the determination (104) is OK, the transfer motor 46 is operated to synchronize the front differential 62 and the front propeller shaft 64, then the transfer 10 is locked, and it is determined whether the axle operation is OK ( 106).

The operation for setting the transfer 10 in the locked state is to operate the transfer motor 46 to the 4WD shift side as disclosed in FIG. 4, and the operation time is further reduced to 0 after the completion of the 4WD switching. 2 seconds or a maximum of 1.5 seconds.

If the above judgment (104) is NG, the transfer motor 46 is operated to the 2WD shift side for 1.5 seconds as shown in FIG. Turn off 4WD switch (108)
I do.

It is determined whether or not the axle operation is OK (10
In 6), if the determination (106) is OK, the axle motor 50 is operated to lock the axle 48, it is determined that the switching is completed, and the 4WD switch (not shown) is turned on (110). Note that the operation of locking the axle 48 is to operate the axle motor 50 to the axle lock side as disclosed in FIG.
The operation time is set to be 0.5 seconds after the end of the above operation and to be completed until the axle lock is completed or a maximum of 5 seconds.

Further, if the determination (106) of whether or not the axle operation is OK is NG, as shown in FIG. 4, the axle motor 50 is operated until the axle free is completed or for a maximum of 5 seconds. And the process proceeds to the switching abnormality process (108).

At the time of switching from the four-wheel drive (4WD) state to the two-wheel drive (2WD) state, as shown in FIG.
F) Perform operation (202). In other words, the transfer motor 46 is operated to the 2WD shift side for 0.5 seconds to
The four-wheel switching rod 40 is moved (see FIG. 4).

At this time, the transfer shift fork 3
A spring 54 of the waiting mechanism 30 is provided on the return side between the 8 and the two-wheel / four-wheel switching rod 40, and when the driving force such as the circulating torque remains, the spring 54 functions to However, after the axle 48 is in the free state, the free state is established after the load is removed.

After the transfer (T / F) operation (202), an axle operation (204) is performed. That is, the axle motor 50 is operated, and the axle 48 is brought into a free state.

The operation of bringing the axle 48 into the free state is performed by the axle motor 50 as disclosed in FIG.
Is set to the axle-free side, and the operation time is set to 0.5 seconds after the completion of the 4WD switching or 0.3 seconds after the end of the above, and set to axle-free completion or a maximum of 5 seconds. are doing.

After the axle operation (204), it is determined that the switching is completed, and the 4WD switch (not shown) is turned off (206).

Thus, the two-wheel / four-wheel switching device 24
The waiting mechanism 30 can be eliminated from the switching motor unit 28 to reduce the size of the switching motor unit 28, and the structure can be simplified, the manufacturing can be simplified, the cost can be reduced, and the economical advantage can be obtained. It is.

Further, by switching control of the transfer motor 46 and the axle motor 50 by the control means 52, it is possible to prevent an excessive switching load from being applied to the transfer 10 and to perform a switching operation at a high speed. In addition, the synchro capacity can be reduced, and the size of the transfer 10 can be reduced.

Further, when the present invention is applied to other models, the control means 52 can be easily diverted and the versatility of the control means 52 can be increased only by changing the energizing time to each motor according to the vehicle. What you get.

Further, at the time of switching from the two-wheel drive state to the four-wheel drive state, the transfer motor 46 is operated to lock the transfer 10, and then the axle motor 50 is operated to lock the axle 48. The control means 52 controls the transfer 1
The switching of 0 will be performed before the axle lock,
The switching load of the transfer 10 can be reduced, and in combination with the elimination of the waiting mechanism 30, the transfer motor 46
And the synchro mechanism can be miniaturized, which is practically advantageous.

The waiting mechanism 30 removed from the switching motor unit 28 is provided on the two-wheel / four-wheel switching rod 40 in the transfer 10, and the transfer shift fork 38 and the two-wheel / four-wheel switching rod are provided. 40
, That is, in the middle of the power transmission path of the power transmitted from the two-wheel / four-wheel switching rod 40 to the transfer shift fork 38 to function when switching from the four-wheel drive state to the two-wheel drive state. When the driving force such as the circulating torque remains, the waiting mechanism 30 does not come off and the axle 48 is in the free state. Thus, the operation order is determined, and the reliability of the operation can be improved.

Further, since the waiting mechanism 30 is formed by the coiled spring 54, the waiting mechanism 30 is formed.
Is simple in construction, easy to manufacture, and can contribute to cost reduction.

It should be noted that the present invention is not limited to the above-described embodiment, and various applications and modifications are possible.

For example, in the embodiment of the present invention, a transfer motor is provided in the switching motor unit, an axle motor is provided on one of the axles of the front and rear wheels, and control for switching between the transfer motor and the axle motor is performed. However, the output of the two motors is made different, that is, the output of the axle motor is set to be smaller than the output of the transfer motor, and the two-wheel drive (2WD) state is changed to the four-wheel drive (4WD). When switching to the state, or from the four-wheel drive (4WD) state
At the time of switching to the wheel drive (2WD) state, a special configuration is possible in which outputs to the two motors are performed simultaneously, and the time until the completion of the operation of each motor is varied depending on the output difference.

In this case, the time required to complete the operation of the axle motor whose output is reduced becomes longer than the time required to complete the operation of the transfer motor, which is common to the stepwise control operation by the control means in the embodiment of the invention. The control operation can be performed with certainty, and the flowchart can be simplified, which is practically advantageous.

[0054]

As described above in detail, according to the present invention, the transmission is connected to the engine mounted on the four-wheel drive vehicle, and the transfer for transmitting the driving force from the transmission to the front and rear wheels is provided. In a vehicle power transmission device for switching a driving state of a four-wheel drive vehicle to a two-wheel drive state or a four-wheel drive state, a transfer motor unit for a two-wheel / four-wheel switching device is provided in a transfer and two-wheel / four-wheel switching is performed The waiting mechanism of the device is removed from the switching motor unit and provided.
A transfer motor is provided in the switching motor unit,
An axle motor is provided on one of the front and rear wheels, and a control means for switching between the transfer motor and the axle motor is provided. Therefore, the waiting mechanism of the two-wheel / four-wheel switching device is eliminated from the switching motor unit. The switching motor unit can be downsized, the configuration is simplified, the production is easy, and the cost can be reduced.
Economically advantageous. Further, by performing switching control of the transfer motor and the axle motor by the control means, it is possible to prevent an excessive switching load from being applied to the transfer, and it is possible to perform a switching operation at a high speed and to reduce a synchro capacity. And the size of the transfer can be reduced. Further, when the present invention is applied to other models, the control means can be easily diverted and the versatility of the control means can be increased only by changing the energizing time to each motor according to the vehicle.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a four-wheel drive vehicle showing an embodiment of the present invention.

FIG. 2 is a schematic sectional front view of a transmission and a transfer.

FIG. 3 is a schematic enlarged sectional front view of a transfer portion.

FIG. 4 is a flowchart for switching from a two-wheel drive state to a four-wheel drive state.

FIG. 5 is a flowchart for switching from a four-wheel drive state to a two-wheel drive state.

FIG. 6 is a schematic enlarged sectional front view of a transfer portion showing the prior art of the present invention.

[Explanation of symbols]

 2 Four-wheel drive vehicle 4 Front wheel 6 Rear wheel 8 Transmission 10 Transfer 12 Transmission case 14 Input shaft 16 Counter shaft 18 Output shaft 22 Transfer case 24 Two-wheel / four-wheel switching device 26 Two-wheel / four-wheel switching mechanism 28 Switching Motor unit 30 waiting mechanism 32 output shaft sprocket 34 front drive sprocket 36 two-wheel / four-wheel switching sleeve 38 transfer shift fork 40 two-wheel / four-wheel switching rod 42 distribution shaft 44 transmission means 46 transfer motor 48 axle 50 axle motor 52 control Means 54 Spring 56 Pinion gear for input 58 Motor output shaft 60 Rack 64 Front propeller shaft 68 Rear propeller shaft

Claims (4)

[Claims] 1. A transmission is connected to an engine mounted on a four-wheel drive vehicle, and a transfer for transmitting a driving force from the transmission to front and rear wheels is provided. In a power transmission device for an automobile that switches between a driving state and a four-wheel driving state, the transfer includes two wheels
A switching motor unit of the four-wheel switching device is provided, and a waiting mechanism of the two-wheel / four-wheel switching device is removed from the switching motor unit. A transfer motor is provided in the switching motor unit, and one of the front and rear wheels is provided. An axle motor is provided on one axle, and control means for switching control between the transfer motor and the axle motor is provided. 2. The control means operates a transfer motor to lock the transfer when switching from the two-wheel drive state to the four-wheel drive state, and then operates the axle motor to lock the axle. A power transmission device for an automobile according to claim 1. 3. The device according to claim 1, wherein the waiting mechanism is disposed between the transfer shift fork and the two-wheel / four-wheel switching rod, and functions when switching from the four-wheel drive state to the two-wheel drive state. Power transmission device for automobiles. 4. The power transmission device for an automobile according to claim 3, wherein said waiting mechanism comprises a coiled spring.