JPS60148721A - Center differential gear lock device of four-wheel driving car - Google Patents

Abstract

PURPOSE:To improve stability of travelling by automatically controlling, in conformity to condition of a wheel, lock.unlock operation of a center differential which distributes power to each differential for front-wheel drive and rear-wheel drive. CONSTITUTION:Front wheels 1, 1 and rear wheels 2, 2 of a four-wheel driving car are connected by means of shafts 3, 4 equipped with front and rear differentials 6, 7 respectively, while the shafts 3, 4 are connected by means of a propeller shaft 5 equipped with both differentials 6, 7 and a center differential 8. In this case, a wheel speed sensor 11 is provided in each wheel 1, 2, and conditions of slippage or brakeage of existing wheels are detected by means of a wheel condition detecting means 41 in conformity to signals sent out from the abovementioned sensors 11. In case existing wheels are in conditions of slippage or brakeage, an actuator 13, for locking the center differential 8, is actuated, by an actuator control means 42, to have said differential 8 locked.

Description

Detailed Description of the Invention (Industrial Application Field) Power transmitted from the engine via the transmission is transmitted to the front differential for front wheel drive and 11/k.
1111 This relates to a center differential lock device for a four-wheel drive vehicle, which is equipped with a center differential that distributes to a rear differential for driving, and automatically locks the center differential in response to one wheel operating condition such as slipping. be.

(Technical Background of the Invention and Prior Art) In four-wheel drive vehicles, a center differential is installed between the front differential and rear differential in order to absorb the difference in rotation between the front and rear wheels and prevent locking when turning at a large steering angle. is provided so that the power transmitted from the engine by the center differential is distributed to the front differential and the differential. Furthermore, this center differential is equipped with a center differential lock device that forcibly disables the operation of the center differential.During normal driving of the vehicle, the center differential lock device is inactivated (unlocked) and the center differential is disabled. It is activated to improve fuel efficiency and reduce running noise, and also reduces the load on the front and rear wheels when the wheels slip (or when slip occurs), such as when driving on muddy ground or when accelerating, or when braking. If the front and rear wheels are braked differently due to conditions such as unbalance, the center differential lock device is activated to disable (lock) the operation of the center differential and lock the front and rear wheels one-on-one. The vehicle rotates to ensure safe driving.

However, in the conventional center differential lock device,
Since the driver had to manually switch between locking and unlocking the center differential lock device, it was difficult to operate the center differential lock accurately depending on the driving condition of the vehicle, and in some cases, the driver had to manually lock or unlock the center differential lock device. Safe driving of the vehicle may be hindered due to operator error.

Incidentally, there are conventionally known systems that determine which wheel is currently slipping by measuring and comparing the rotational speed of each wheel, and informing the driver of this (for example, Japanese Patent Application Publication No. 1987-.

90 Kono No. 7), this known example only detects the slip state of the wheels, and the driver must operate the center differential lock device himself, so it is difficult to ensure driving safety. There is still room for improvement in this regard.

(Object of the Invention) The present invention provides a V! In a one-wheel drive vehicle, driving safety is improved by automatically and accurately locking and unlocking the center differential in response to the ever-changing wheel conditions. This was developed for the purpose of providing a center differential lock device for four-wheel drive vehicles.

(Structure of the Invention) The center differential lock device for a four-wheel drive vehicle of the present invention has a seventh embodiment.
As shown in the figure, in a four-wheel drive vehicle equipped with a center differential that distributes the power transmitted from the engine through the transmission IO to the front differential 6 and rear differential 7, the front wheels /, /, rear wheels, - In response to the wheel speed signal of each wheel detected by a wheel speed signal means such as a wheel speed sensor // provided respectively in the wheel state detecting means 1/, the current slip state or braking state of the wheel is detected; When the wheels are currently in a slip state or a braking state, an actuating signal is output from the actuator control means II2 to a locking actuator 13 of the center differential g, and the actuator 13 locks the center differential t. It is characterized by the fact that

(Example) Hereinafter, the center differential lock device for a four-wheel drive vehicle of the present invention will be explained based on FIGS. 2 and 3. FIG. A system diagram of the [wI system] of a wheel drive vehicle is shown, and in the diagram, the symbol 1 is the front wheel of the vehicle, and 2 is the rear wheel.

Among the front wheels /, / and the rear wheels 2, 2, the front wheel 1. / are connected by a front axle 3 with a front differential 6, and the rear wheels 2.2 are each connected by a rear axle 2 with a differential 7. Furthermore, this front differential≦trailer differential 7 means that the front shaft SA located on the front differential 6 side and the rear shaft j located on the rear differential 7 side
B and B are connected to each other by a propeller shaft 5 which is connected by a center differential t, and the power transmitted from the engine through the transmission 10 is distributed to the front differential t and the front differential 7. .

Also, center differential! A multi-disc clutch 2 is installed between the rear shaft 3B and the rear shaft 3B, and is engaged or disengaged as appropriate by an actuator 13 that receives a signal from a controller DAO, which will be described later. The multi-disc clutch 12 is engaged, the front differential of the center differential g is disabled, and the front shaft 5A
and rear axle jB are connected as a pair, and when actuator/3 is OFF, the multi-plate clutch 12 is in a disengaged state and operation of the center differential is enabled, and the front axle SA and rear axle SB are rotated at a predetermined rotation ratio. It can be rotated by

On the other hand, wheel speed sensors //, //, etc., which detect the rotational speed of each wheel, are attached to the front wheels l, / and the rear wheels m2, 2, respectively. Signals from the respective wheel speed sensors //, //, etc. are input to a controller≠0, which will be described later, as differential lock operation signals.

As shown in FIG. 3, the controller IlO includes four waveform shapers 2/, 2/, which receive signals from the respective wheel speed sensors //, //, convert them into pulse signals, and output the pulse signals. ··and,
Four counters 2, 2, 22, .
q latch circuits 23,23... which latch the data output from each timing signal output from the timer 26 and output it as the current wheel speed of each wheel, and each latch circuit 23,23... An adder 27 that adds the wheel speed data of each wheel for each timing signal, and a division that divides the data output from the adder 27 for each timing signal to calculate the current average wheel speed of all wheels! 112
g, each of the latch circuits, 27.23... subtract the current wheel speed of each axle output from the average wheel speed output from the divider jf to calculate the difference in average wheel speed (differential speed) for each axle. The differential speed receives the output from the ψ subtracters 211, 211, . . . output for each wheel, and each subtractor 2I1. greater than (i.e.
If there is a wheel in a slipping state or a wheel smaller than the set value (that is, in a braking state) among the four wheels, it is determined that it is necessary to lock the center differential R, and the amplifier 30 is immediately activated. The determination circuit 2q outputs an operation signal (differential lock signal) to the actuator 13 via the determination circuit 2q. The determination circuit 2q is configured to output a differential lock signal to the actuator 13 regardless of the wheel speed of each wheel when a manual lock switch llll provided on the driver's seat side is turned on.

In a four-wheel drive vehicle equipped with a center differential lock device configured as described above, during normal driving with the center differential set to the unlocked state, for example, one of the rear wheels 2. If one of the wheels slips in mud or the like, each wheel 1. /
, 2. ．． The judgment circuit 2 of the controller DAO operates in response to the signals from the wheel speed sensors provided in the wheel speed sensor // , //...
9, the presence of a wheel in a slipping state is detected, and in response to an activation signal from the determination circuit 2q, the actuator 13 performs a differential lock operation and the center differential r is locked. Therefore, even though the rear wheels are in a slip state, the front wheels /, / rotate by receiving the power from the engine 9, and the running stability of the vehicle is ensured, making it possible to easily escape from the mud. become. Furthermore, even if the wheels slip during acceleration, the center differential r is locked by the same control procedure as in the above case, and acceleration is performed safely and smoothly.

On the other hand, if you perform a braking operation while driving at high speed in an unlocked state, the same amount of braking force is applied to each wheel at the same time, so all wheels must stop at the same time. However, in reality, the load distribution amount is different between the front wheels /, / and the slow wheel, so for example, in a front engine car, 11
The rear wheels 2 and 2, which have less weight, are the front G'h, which has greater wheel weight.
A so-called "katakuchitsuku" situation occurs in which the motor stops earlier than /.
This impairs driving stability and reduces braking performance, but in the case of the illustrated embodiment, the determination circuit 2q of the controller 110 detects the single-side lock condition at the time when the single-side lock condition occurs. Immediately upon receiving this, the center differential t is locked by the actuator 13, and the front wheels / and rear wheels 2 and 2 are simultaneously braked at the same deceleration rate. Therefore, no spin phenomenon occurs, and the running stability and braking performance of the vehicle are improved. (Effects of the Invention) The center differential lock device for a four-wheel drive vehicle of the present invention detects the slip state of the wheels by calculation from the wheel speed of each wheel, and automatically controls the locking/unlocking operation of the center differential. Compared to conventional center differential lock devices where the driver manually locks and unlocks the center differential, this system allows the center differential to be locked and unlocked more accurately depending on the wheel condition. This has the effect of improving driving safety accordingly.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of a center differential lock device for a four-wheel drive vehicle according to the present invention, Figures 2 and 2 are system diagrams of a center differential lock device for a four-wheel drive vehicle according to an embodiment of the present invention, and Fig. FIG. 3 is a control block diagram of the illustrated controller. /...Front wheel 2...Rear wheel 3...Front wheel axle d...Rear wheel axle S...Propeller axis t...Front differential 7... ... Rear differential R ... Center differential 9 ... Engine 10 - Participating torque transmission / / ... Wheel speed sensor / Co ... Multi-plate clutch 13 ...Actuator/l...Manual lock switch button...Wheel condition detection means lI2...Actuator control means Applicant: Hiroshi Ohama, patent attorney, Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] /. In a four-wheel drive vehicle equipped with a center differential that distributes the power transmitted from the engine through the transmission to a front differential for front wheel drive and a rear differential for rear wheel drive, the wheel speed detection means for detecting rotational speed; receiving a signal from the wheel speed detection means;
wheel speed detection means for detecting at least a slip state of the wheels based on a difference in wheel speed between the wheels;
131. A center differential lock device for a four-wheel drive vehicle, comprising actuator control means for receiving a signal from a detection means and sending an activation signal to a locking actuator of the center differential.