JPS62279136A - Four-wheel drive control method - Google Patents

Abstract

PURPOSE:To improve the drivability and ride feeling by controlling the transmission torque capacity so that the shock caused by the variation of the transmission torque capacity and the speed change shock are generated at the same time. CONSTITUTION:Hydraulic controllers 9 and 22 are operated on the basis of the control signal supplied from a controller 45, and perform the selection control for the speed change stages of a speed change gear 7 and the engagement- release control of a differential control clutch 21. In this case, the engagement and release of the differential control clutch 21 accompanied with the selection for the speed change stages of the speed change gear 7 are executed synchronously with the selection for the speed change stages of the speed change gear 7 so that the shock due to the variation of the transmission torque capacity of the differential control clutch 21 and the speed change shock are generated at the same time. Therefore, the successive generation of two shocks on the selection of speed change stages is suppressed, and the deterioration of drivability and ride feeling can be avoided.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention Industrial Application Field The present invention relates to a method of controlling a four-wheel drive device used in vehicles such as automobiles, and particularly relates to a control method for a four-wheel drive device used in a vehicle such as an automobile. The present invention relates to a fl control method for a four-wheel drive device having the following.

BACKGROUND ART As one of the four-wheel drive devices used in vehicles such as automobiles, there is a center differential 8 that performs differential operation between rear wheels and front wheels, and a center differential that selectively operates the differential operation of the center differential device. Stop and select rear and front wheels 1R
Already, 12 four-wheel drive systems having a differential limiting device such as a differential control clutch that is directly connected to the front and rear wheels have been proposed.
This is disclosed in Japanese Patent Application Laid-open No. 55-7242'08.

In situations where a four-wheel drive system is used as described above, when the differential control clutch is disengaged, the center differential operates as a differential, thereby avoiding tight corner braking and turning. On the other hand, when the vehicle is traveling smoothly and the differential control clutch is engaged, the center differential device (+)ff is not operated for differential operation, and the front and rear wheels are directly connected, resulting in a four-wheel drive state. Driving performance is improved.

The problem to be solved by the invention is to control the transmission torque capacity of a differential limiting device such as a differential control system according to the input torque applied to a center differential device, or according to the gear position of a transmission device. It is considered to do. In this case, the transmission torque capacity of the differential limiting device changes each time the gear stage of the transmission changes, and therefore, the shock generated due to the change in the transmission torque capacity of the differential limiting device during gear shifting. Shift shocks may occur one after another with a slight time difference, deteriorating the driving feeling and ride comfort.

An object of the present invention is to provide a control method for a four-wheel drive device that controls the transmission torque capacity M of a differential limiting device without causing shocks one after another during gear changes.

Means for Solving the Problems According to the present invention, the above-mentioned objects include one input member and two output members, one for the rear wheels and one for the front wheels, so that there is no difference between the rear wheels and the front wheels. A center differential device that performs operation, and two members of the input member and the two output members of the center differential device are connected to each other with a variable transmission torque capacity to limit differential operation of the center differential device. In a method of controlling a four-wheel drive device having a differential limiting device? The transmission torque capacity control during gear shifting of the yJ differential initial limiter is performed in synchronization with the gear change of the transmission so that the shock caused by the change in the transmission torque capacity and the shift shock occur at the same time. This is achieved by a four-wheel drive control method that is characterized by the following:

Effects and Effects of the Invention According to the method for controlling a four-wheel drive device according to the present invention, the transmission 1-lux capacity r at the differential limit Ja position during gear shifting is
II till is performed in synchronization with the gear shift of the transmission so that the shock caused by the change in the transmitted torque capacity and the shift shock are generated at the same time, so that the shift of the gear of the transmission is performed. The shift shock and the shock due to the change in transmission torque capacity of the differential limiting device do not occur one after another with a time difference, and the shock at this time only needs to be experienced once, which deteriorates the driving feeling and ride comfort. This will be avoided.

EXAMPLES The present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a skeleton diagram showing a four-wheel drive system used to implement the control method according to the present invention. In the figure, reference numeral 1 indicates an internal combustion engine (J3). Transfer devices 3 are connected in sequence.

The vehicular automatic transmission [2] has a hydraulic torque converter 5 of a general structure provided in a converter case 4 and a gear type transmission 7 provided in a transmission case 6, and The input member 8 of the converter 5 is drivingly connected to an output shaft (not shown) of the internal combustion fiOQ1 (a crankshaft (not shown)), so that the rotational power of the internal combustion engine 1 is applied to the transmission 7 via the hydraulic torque converter 5. . The transmission 7 is a well-known transmission comprised of a planetary wheel mechanism or the like, and changes between a plurality of gears, and its gear change is controlled by a hydraulic control device e9. .

The four-wheel drive transfer device 3 is a planetary gear type L-center differential device 1 for full-time 4WD.
0, the center differential device 10
Ha, transmission V! It has a gear rear 11 as an input member to which rotational force is applied from 17, a planetary pinion 12 carried by the carrier, a sun gear 13 and a ring gear 14 that mesh with the planetary pinion 12, and the ring gear 14 is connected to the rear wheel. Connected to drive shaft 15, sun gear 1
3 is connected to a sleeve-shaped +)Q wheel drive intermediate '71!16 coaxial with the rear wheel drive shaft 15. The four-wheel drive transfer device 3 has ilQ wheel drive intermediate @16 and ilZ.
A front wheel drive shaft 17 is provided in the row, and the front wheel drive intermediate shaft 16 and the front wheel drive shaft 17 are drivingly connected by an endless chain 20 that meshes with sprockets 18 and 19 that are attached to each of them. ing.

The four-wheel drive transfer Y@W13 is equipped with a hydraulically operated bullet initial control clutch 21 that selectively connects the sun gear 13 and the ring gear 14, and the operation of the differential control clutch is controlled by the four-wheel drive transfer. This is performed by a hydraulic system ef22 installed in the device 3.

One end of a rear propeller shaft 24 is drivingly connected to the rear wheel drive shaft 15 through a universal joint 23 .

One end of a front propeller shaft 26 is connected to the front wheel drive shaft 17 via a universal joint 25 . Front propeller @
26 extends on one side of the vehicle automatic transmission 2 substantially parallel to its axis, and connects one end of the drive pinion shaft 31, which is the input shaft of the front differential device 30, with a universal joint 27 at the other end. is connected to. The drive pinion shaft 31 is rotatably supported by a differential shaft 32 integrally formed with a cast iron oil pan 29 of the internal combustion engine 11.

A drive pinion 33 made of a bevel gear is provided at the end of the drive pinion shaft 31, and the drive pinion meshes with a ring gear 34 of the front differential device 30.

The hydraulic control devices 9 and 22 operate based on the control signal from the electric control device 45 to control the gear change of the transmission 7 and the engagement/disengagement control of the differential Np control clutch 21. It has become. The control I neck 45 includes a microcomputer with a general structure, and receives information about the vehicle speed from a vehicle speed sensor 46, information about the throttle opening of the internal combustion engine 1 from a throttle opening sensor 47, and receives information about the throttle opening of the internal combustion engine 1 from a manual shift position sensor 48. Information about the range can be obtained from the manual selector switch 49 via pinta-dif? It is given information regarding whether or not it is in the differential lock mode, and basically controls the gear shift of the transmission 7 according to a predetermined shift pattern according to the manual shift range, vehicle speed, and throttle opening. [1] A control signal for engagement i% control of the pull-up clutch 5a is output to the hydraulic cylinder I211 device 9, and when the center differential lock mode is in effect, the gear of the transmission ff17 is set to the highest speed gear, A signal that causes the differential control clutch 21 to engage unless the gear is in overdrive gear (fourth gear), and a signal that causes the differential control clutch 21 to engage in other cases.
A control signal for prohibiting the engagement of the differential control clutch 21, that is, for disengaging the differential control clutch 21, is output to the hydraulic control device ff122.

As a result, even if the differential υ1111 clutch 21 is engaged in the center differential lock mode, it is forcibly released when the gear shift of the transmission 7 is hairshifted to the A-patrive gear. This puts the center differential device 10 in a state where it can perform differential operation, and it is possible to avoid generation of circulating torque in the power transmission system due to the difference in rotational speed between the front wheels and the rear wheels.

When the gear position of the transmission 7 is downshifted from the overdrive position in the center differential lock mode, the engagement of the differential #Jυ control clutch 21 is automatically returned to improve driving performance and braking performance. The vehicle returns to four-wheel drive mode with direct connection to the front and rear wheels.

The engagement and disengagement of the differential control clutch 21 when changing the gear stage of the transmission device 7 as described above is performed so that the shock due to the change in the transmission torque capacity of the bullet initial control clutch 21 and the shift shock are generated at the same time. , as shown in FIG. 2, is performed in synchronization with the shift of the gear position of the transmission 7. The time from the start of gear change until a shift shock actually occurs, and the time from the start of engagement or release of the differential control clutch 21 until a shock associated with the change actually occurs. They are different from each other, but the former is longer than the latter, so as shown in FIG. This has started to occur.

As a result, the switching shock caused by the engagement and disengagement of the differential control clutch 21 and the shift shock caused by the shift of the transmission device 7 occur simultaneously, and the switching shock of the differential control clutch and the shift shock occur one after another during gear shifting. This is avoided.

Note that the control method according to the present invention is limited to control for disengaging differential I and II control clutches at a specific gear stage, and
The present invention is also applied to the case where the transmission torque capacity of a differential limiting device such as a start-of-arrival control clutch is variably υ controlled in various manners in accordance with gear change.

Although the present invention has been described in detail with respect to specific embodiments above, the present invention is not limited thereto (
It will be apparent to those skilled in the art that various embodiments are possible within the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing an example of a four-wheel drive device used to implement the control method according to the present invention, and FIG. 2 is a graph showing control characteristics in the M-group method of the four-wheel drive device according to the present invention. . 1...Internal combustion engine, 2...Automatic transmission for vehicles, 3...
- Four-wheel drive transfer device, 4... converter case, 5... hydraulic torque converter, 6... transmission case, 7... transmission device, 8... input member. 9... Hydraulic control device, 10... Center differential device, 11... Carrier, 12... Planetary pinion, 13... Sun gear, 14... Ring gear. 15... Rear wheel drive shaft, 16... Front wheel drive intermediate shaft,
17... Front wheel drive shaft, 18. One... Sub O-ket, 20... Endless chain, 21... Differential control clutch, 22... Hydraulic control device, 23... Universal joint, 2
4...Rear propeller shaft, 25...Universal joint, 26.
...Front propeller shaft, 27...Universal joint, 29.
··Oil pan. 30...Front differential device, 31...
・Drive pinion shaft, 32... Differential case, 3 pieces 3... Drive pinion, 34... Ring gear, 45... Control gi position, 46... Medium speed sensor 1), 47... Throttle opening sensor, 48...Manual shift position sensor, 49...Manual changeover switch

Claims (1)

[Claims] A center differential device includes one input member and two output members, one for rear wheels and one for front wheels, and performs differential operation between the rear wheels and the front wheels; In a method for controlling a four-wheel drive device, the four-wheel drive device includes a differential limiting device that connects two of the two output members to each other with a variable transmission torque capacity and limits differential operation of the center differential device,
Controlling the transmission torque capacity of the differential limiting device at the time of gear shifting is performed in synchronization with the gear change of the transmission so that a shock caused by a change in the transmission torque capacity and a shift shock are generated at the same time. A four-wheel drive device control method characterized by: