JPS5856924A - Drive change-over controller from two to four wheel - Google Patents

Abstract

PURPOSE:To simplify a control system and improve responsive property by sensing slip occurrence through rotational angular acceleration in two wheel drive to immediately change over to four wheel drive and return it to two wheel drive by a predetermined releasing signal. CONSTITUTION:In a control system for automatic changing over two-four wheel drive by an electromagnetic clutch 32, the pulse signal of a rotation sensor 33 is differentiated by a differentiating circuit 35 to be compared with a set value by a comparator 36 while the comparator 36 is connected to a current controlling circuit 39 in the clutch 32 through a hold circuit 38. The signal of a hold releasing signal generating circuit 40 for judging acceleration-off, brake-on, vehicle speed zero, etc is constituted to release the signal of the comparator 36 held by the circuit 38. Thus, slip in travelling has rotational acceleration sensed immediately by the comparator 36 so that said signal of the comparator is continued in the circuit 38 while an accelerator pedal is depressed and two wheel drive is recovered by the releasing signal of the circuit 40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bar-l-time type four-wheel drive vehicle which normally has two-wheel drive using one of the front and rear wheels, but which performs four-wheel drive mode as needed. This invention relates to a 4-wheel drive switching control device that automatically switches to 4-wheel drive when a wheel slip occurs.

In such a bar one-time type four-wheel drive vehicle, switching between 2.4-wheel drive and four-wheel drive is left to the driver's operation, so when driving on a road with a low coefficient of friction, if slipping occurs, the four-wheel drive When it comes to drive, even though it is desirable due to improved handling and fuel efficiency, the switch to 4-wheel drive is not made and the original performance of a 4-wheel drive vehicle may not be fully realized. .

In order to improve this point, during two-wheel drive, the state of slippage of the drive wheels is constantly sensed, and when slippage occurs, (
1 Automatically switches to 4-wheel drive.
Already filed by the applicant on Thursday I'1
83319''J.1] Just one year ago, we focused on the fact that slippage was determined based on the rotational difference between the rear wheels, and based on this rotational difference, we changed to four-wheel drive. .In addition, at least two rotation pins to detect the rotational speed J mark of the front and rear wheels, a computing unit for calculating the JA calculation, etc. are required, making the structure complicated.In addition, the rotation difference is After the wheels have rotated 1σ, it is impossible to obtain a clear value necessary for determining slippage, so it is necessary to determine whether the wheels are 4-wheel drive or not. Once upon a time, I had poor response IQ.

The present invention has been developed in view of the above two circumstances (C), and when a slip occurs, a much larger rotational fluctuation occurs in the drive wheel than in the case of acceleration, and this is caused by rotational angular acceleration that causes the slip to begin. Focusing on the fact that the stage can be detected early, the rotational angular acceleration of the two-wheel drive system is determined, the occurrence of slip is determined from this, and the switching response is determined by switching to four-wheel drive. It is an object of the present invention to provide a two- and four-wheel drive switching control device that has improved performance and reliability, and is also simplified in terms of 414Ti.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. First, in Fig. 1, the transmission system of a part-time four-wheel drive vehicle to which the present invention is applied will be explained.
It is based on a two-wheel drive system, where 1 is the crankshaft from the engine, 2 is the clutch, and 3 is the manual transmission. The transmission 3 is a constant mesh type 5, in which an output shaft 6 is arranged parallel to an input shaft 4, and a first speed gear 1 is in mesh with the output shaft 4.6. , 11 gears A78, 12 for second speed, gears 9, 13 for third speed, and gears 10, 14 for fourth speed are provided. Each of these gears 7 is connected to a two-piece synchronization mechanism 15.1f3. By selectively connecting one of the output shafts 4 and 6 to the first speed or first speed, the input shaft 4
The 112 gear 1/17 is connected to the gear V on the sleeve side of one synchronous machine 4M1f'i via the idler gear 1).
By meshing with 718, it is possible to make 1!2 return steps.

A drive pinion 5a is integrally formed in front of the output shaft 6 of the transmission 3, and is disposed below the input shaft 4 between the clutch 2 and the transmission 3. The drive pin 5a is engaged with the crown gear 57511 of the final wheel reduction gear 5. In addition, the power from the transmission 3 is directly transmitted to the front wheel C via the front final reduction gear +i, and the two-wheel drive 11 that goes to the front wheels is also transmitted to the output shaft of the transmission 3. The side opposite to the drive pinion 5a of 6 extends rearward, and is attached to the rear of the transmission 3.
'19.20 is connected to a gear, and this gear 1) 20's shaft 21 is a 2.4-wheel drive l, 7II! 1! (for example, via an electromagnetic clutch 32).
Transmission is configured from the attribe shaft 23 to the rear wheel final reduction gear 25 and the rear wheels via the propeller shaft 24. The electromagnetic clutch 32 includes a drive member 27 connected to a drive side shaft 21 via a drive plate 26, and a drive member 27 connected to a driven side shaft 23 and arranged with a slight groove inside the drive member 21. The member 28 is assembled (pulled) inside the drive member 21, and has an electric conductor 29 accommodated in the gap between both members 27 and 28;
By supplying a predetermined clutch current to the coil 29 through the brushes 30 and slip ring 31 that are in sliding contact with each other,
By generating magnetic lines of force, accumulating electromagnetic powder, and magnetically coupling the two members 27 and 28, the clutch is engaged. In this way, when the clutch current is zero, no magnetic lines of force are generated and there is no coupling by the 'tfi magnetic particles, so the electromagnetic clutch 32 is in a released state, power transmission to the rear wheels is cut off, and a predetermined clutch current is maintained. When the electromagnetic clutch 32 is engaged due to the supply, power is also transmitted to the rear wheels and four-wheel drive driving is performed.

5- Next, in FIG.
To explain the Ll system for wheel drive switching, it has a rotational lever 33 that generates a pulse, and this rotation sensor 33
A pulse signal corresponding to the rotational speed from DA change circuit 3
The self-velocity lα is obtained by calculating the 4-ana 1 cog value, which is further differentiated by a differentiating circuit 35 to obtain the angular acceleration curve C). Here, the angular acceleration If G; i suddenly accelerated J, U r JM, then b
Although the value is small, in order to exclude this case, the comparator 3G compares the reference voltage generation circuit 31 with the setting 1+rj, which corresponds to the acceleration at this time, and detects a value that is larger than J. If this occurs, it is determined that a slip has occurred. The comparator 3G is electrically connected to the brush side of the electromagnetic clutch 32 via the hold circuit 183B and the clutch current control circuit 39.
If a signal is input from J, the state will be maintained, and if the actuator A), play: I= A, vehicle speed is zero, etc. will be determined. 1. The release signal from the circuit 40 releases the holding. ';・]-'C
There is.

Clutch current control circuit 39 is supplied with C, 1 and signal from manual selector switch 41; When input η is input, a predetermined clutch current is supplied.

Explaining the operation of the device of the present invention constructed in this way, even if angular acceleration is detected during acceleration without slipping or during normal driving, the comparator 3 is removed.
No signal is output from 6. Therefore, crudge current control 31
The input signal to 1 circuit 39 is only the signal from manual changeover switch 41 or 1, and when switch 41 is off, circuit 3
Since there is no input signal to 9, the clutch current becomes zero,
Two-wheel drive driving is performed with the electromagnetic clutch 32 released. Then, when the switch 41 is turned on by the driver's will and a signal is input to the circuit 39, the circuit 39 supplies a predetermined clutch current to the electromagnetic clutch 32.
(It engages with J: turns, thereby switching to four-wheel drive.

Next, when a slip occurs at the time of starting or while driving, the slip is immediately detected by the comparator 36 because a large rotational angular acceleration occurs at the stage where the angular displacement of the wheel is small, that is, at the beginning of slip, and the slip is immediately detected by the hold circuit 38. A signal is input to the clutch current control circuit 39 via J-. Therefore,
In this circuit 39]J.

When there is no signal from the manual changeover switch 41, a predetermined clutch current is supplied, thereby automatically switching from two-wheel drive to four-wheel drive. This state continues as long as the accelerator pedal is pressed by the hold circuit 38 and the vehicle accelerates. After acceleration, the hold release signal is released by the release signal from the generation circuit 40, and the state returns to two-wheel drive. , 4-wheel drive driving is performed only when there is substantial slippage due to depression of the C accelerator pedal.

From the above explanation, it is clear that the present invention focuses on sudden fluctuations in wheel rotation when slip occurs, and
J: Detects the slip occurrence state of the rotational angular acceleration,
Since it automatically switches to 4-wheel drive, the structure of the control system is simplified compared to the system that judges based on the difference in rotation, and the response speed is less than a
, there is less risk of malfunction. When the control system detects slippage, it is held in that state and then released by a release signal, so four-wheel drive performance can be reliably demonstrated without being affected by slippage fluctuations.

Note that the present invention can be similarly applied to cases where a hydraulic clutch is used instead of an electromagnetic clutch in the transfer device 22.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a four-wheel drive vehicle to which the present invention is applied, and FIG. 2 is a circuit diagram showing an embodiment of the device according to the present invention. 3... Transmission, 5... Front wheel final reduction gear, 22...
Transfer device, 25... Rear wheel final reduction device, 32.
...Electromagnetic clutch, 33... Rotation sensor, 34...
DA conversion circuit, 35... Differentiation circuit, 36... Comparator, 38... Hold circuit, 39... Clutch current control circuit, 40... Hold release signal generation circuit, 41.
...Manual changeover switch. 9-

Claims (1)

[Claims] Power is directly transmitted to one of the front and rear wheels, and power is also transmitted to the other of the front and rear wheels by engaging a clutch if necessary.4
In wheel drive vehicles, the rotational angular acceleration of the two-wheel drive system is determined to detect the occurrence of slip, and when slip occurs, 2-wheel drive is immediately performed.
2. A two-wheel drive switching control device, characterized in that it is configured to automatically switch to four-wheel drive if it is in a wheel drive state, and return to two-wheel drive again in response to a predetermined release signal.