JPH0662068B2 - Four-wheel drive controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a four-wheel drive control device, and more particularly to a signal for at least one of vehicle speed and engine speed during four-wheel drive during braking or rain. The present invention relates to a four-wheel drive control device for improving steering operability by setting two-wheel drive when the value is less than a predetermined value.

[Prior Art] Some vehicles have a four-wheel drive (four-wheel drive, 4WD) structure that transmits driving force to all four wheels.

This four-wheel drive vehicle uses only one-axis two-wheel drive (2WD) in normal traveling, and transmits the driving force to the two-axis four-wheels when driving over a rough road or rough terrain.

[Problems to be Solved by the Invention] By the way, in the conventional four-wheel drive control device, the vehicle is automatically switched from two-wheel drive to four-wheel drive by an electric signal which is a signal during braking or rain. There are some that ensure the running stability of the vehicle.

However, even at low speeds and low speeds such as when entering a garage where the steering angle is large, the four-wheel drive state is applied due to the above conditions, and unnecessary force is applied to the steering system, making it difficult to operate the steering wheel. Is deteriorated.

Therefore, in order to eliminate the above-mentioned inconvenience, an object of the present invention is to input a signal of at least one of a vehicle speed and an engine speed, and to drive two wheels when this at least one signal is less than a predetermined value. By providing the control unit, the two-wheel drive is performed by the control unit when at least one of the signals becomes less than a predetermined value, for example, at low speed or low rotation, the steering wheel operation can be facilitated, the steering operability can be improved, and the steering system can be improved. The purpose of the present invention is to realize a four-wheel drive control device that can reduce the rigidity and can be manufactured at a low price without applying a necessary force.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a four-wheel drive control device for automatically switching a vehicle from two-wheel drive to four-wheel drive during braking or rainfall. A control unit is provided which inputs at least one signal of the engine rotation speed and the two-wheel drive when this at least one signal is less than a predetermined value.

[Operation] With the configuration described above, at least one signal of the vehicle speed and the engine speed is input to the control unit, and when at least one of the signals is less than the predetermined value by the control unit, for example, at low speed or low rotation speed. It is a two-wheel drive, and the steering operation is improved by facilitating the steering wheel operation.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show an embodiment of the present invention. First
In the figure, 2 is a four-wheel drive controller. A control unit 4 is provided in the four-wheel drive control device 2, and a brake switch 6 and a brake lamp 8 that are turned on during braking are connected to the control unit 4, and a wiper switch 10 that is turned on during rain, for example, when driving the wiper. The wiper motors 12 are connected to each other, and are configured to output a signal, for example, an electric signal, to the control unit 4 during braking or rain. In addition, a solenoid valve 14 that opens and closes by receiving a signal from the control unit 4 is provided, and the intake pipe negative pressure 16 is applied to the actuator 18 by the opening and closing operation of the solenoid valve 14, and the two wheels and four wheels are connected via the wire 20. A control lever 22 is provided which operates to switch between the wheels.

A vehicle speed switch 24, which is turned off at a low speed, that is, below a predetermined vehicle speed, which is a predetermined value, is connected to the control unit 4, for example, by a vehicle speed sensor (not shown), and the engine speed is detected to detect low engine speed, that is, below a predetermined speed A rotation speed switch 26 composed of an ignition coil is also connected to detect this. Further, the control unit 4 is turned on only when four-wheel drive 4
The WD switch 28 is connected. Then, at the time of low speed and low rotation during four-wheel drive, electric signals of the vehicle speed switch 24 and the rotation speed switch 26 are input to the control unit 4, and the control unit 4 switches from four-wheel drive to two-wheel drive. Controlled.

Further, if the low-speed, low-rotation state is reached immediately before switching from two-wheel drive to four-wheel drive, the switching operation from two-wheel drive to four-wheel drive is prohibited and the two-wheel drive state is maintained.

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

First, it is determined whether the 4WD switch 28 is ON,
As shown in FIG. 3 (a), if YES, the control is switched to four-wheel drive, and if NO, the brake switch 6 is turned ON.
Whether or not it is determined (see FIG. 3 (b)). And Y
In the case of ES, it is determined whether or not the rotation speed switch 26 described later is ON (see FIG. 3C), and in the case of NO, it is determined whether or not the wiper switch 10 is ON. When the wiper switch 10 is OFF, that is, when it is NO, the control is switched to the two-wheel drive, and when it is YES, it is determined whether or not the rotation speed switch 26 is ON (FIG. 3 (c)).
reference). Then, in the case of YES, it is determined whether or not the vehicle speed switch 24 is ON (see FIG. 3 (d)), and in the case of NO, switching control to two-wheel drive is performed. Next, vehicle speed switch 2
When 4 is ON, that is, YES, the control is switched to four-wheel drive, and when it is NO, the control is switched to two-wheel drive.

As a result, the release of the four-wheel drive, that is, the switching operation from the four-wheel drive to the two-wheel drive, or the switching to the four-wheel drive can be prohibited to set the two-wheel drive state at the low speed and the low rotation, and the steering wheel operation becomes easy. For example, it is possible to improve the steering operability when entering the garage where the steering angle is large.

In addition, since unnecessary force is not applied to the steering system at low speed and low rotation, the rigidity of the steering system constituent members can be reduced, which contributes to reduction of the weight of the vehicle and cost reduction, which is practically advantageous. .

Further, when the vehicle is not braking or raining at low speeds or at low speeds, the four-wheel drive control is automatically performed to improve the usability of the four-wheel drive control device.

The present invention is not limited to the above-mentioned embodiments, and various application modifications are possible.

For example, in the embodiment of the present invention, the electric signals of the vehicle speed and the rotation speed are input to the control unit,
The electric signal of at least one of the vehicle speed and the rotation speed may be input to the control unit to cancel the four-wheel drive.

[Effects of the Invention] As described in detail above, according to the present invention, a control unit that inputs a signal of at least one of a vehicle speed and an engine speed and performs two-wheel drive when the signal of at least one is less than a predetermined value is provided. Since it is provided, at least one of the signals becomes less than the predetermined value, for example, when the vehicle is driven at low speed or low speed, the control unit drives the two wheels to facilitate the steering wheel operation and improve the steering operability. In addition, since unnecessary force is not applied to the steering system, the rigidity of the steering system constituent members can be reduced, the weight of the vehicle can be reduced, the cost can be reduced, and it is practically and economically advantageous.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a block diagram of a four-wheel drive control device, FIG. 2 is a flowchart showing a switching operation, and FIGS. 3 (a) to 3 (d) are various switches. O
It is explanatory drawing which shows N * OFF state. In the figure, 2 is a four-wheel drive control device, 4 is a control unit, 6 is a brake switch, 10 is a wiper switch, 14 is a solenoid valve, 16 is an intake pipe negative pressure, 18 is an actuator, 22 is a control lever, and 24 is a vehicle speed. switch,
26 is a rotation speed switch and 28 is a 4WD switch.

Claims (1)

[Claims] 1. A four-wheel drive control device for automatically switching a vehicle from two-wheel drive to four-wheel drive during braking or rain, and at least one of a vehicle speed and an engine speed is input to the four-wheel drive control device. The four-wheel drive control device is provided with a control unit that drives two-wheel drive when the signal is less than a predetermined value.