JPS6229428A - 2-4 wheel drive converting device - Google Patents

Abstract

PURPOSE:To prevent a slip generation in the early stage, by detecting the inclination with an inclination sensor in an up-slope running, converting to the 4-wheel drive when the inclination exceeds a specific angle, and moreover, making a condition to convert to the 4-wheel drive easily when a rainfall is detected. CONSTITUTION:In a car running condition, the slip rate S is found in a micro computer 5 from outputs of a front wheel sensor 1 and a rear wheel sensor 2, and the S is compared with a preset value alpha. When S >=alpha, the 4-wheel drive command is generated, and the car is converted to the 4-wheel drive through the 2-4 wheel drive converting mechanism 6. When S<alpha, the running road inclination theta through an inclination sensor 4, and the rain detecting signal through a rain sensor 3 are input, and if a rainy condition is detected, the inclination theta is adjusted to be theta=K.theta (K is a constant of one ore more). Then the absolute value of the inclination theta is decided whether it is equal to the specific value beta or more or not, and if ¦theta¦>beta, the 4-wheel drive command is generated, and if ¦theta¦<=beta, the 2-wheel drive command is generated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a two-wheel drive system that selectively switches between two-wheel drive and four-wheel drive.
-Relating to a four-wheel drive switching device.

[Conventional technology]

Conventionally, as this type of device, there is a part-time type 2-4 wheel drive switching device that switches from 2 wheel drive to 4 wheel drive by manual operation or by detecting the occurrence of slippage.

It is also known that with this 2-4 wheel drive switching device, it is better to switch to 4 wheel drive even when driving on a slope.

However, when switching to four-wheel drive when driving on a slope,
Depending on the condition of the road surface, it may be better to change the switching timing.

The present invention focuses on the fact that slips are more likely to occur during rainy weather, and has developed a system for driving four-wheel drive on slopes with a smaller inclination angle than normal during rainy weather.
The system switches to wheel drive, and performs appropriate four-wheel drive switching when driving on a slope.

[Means for solving problems]

In order to achieve the above object, the present invention provides a 2-4 wheel drive switching device equipped with a 2-4 wheel switching mechanism that selectively switches between 2-wheel drive and 4-wheel drive, as shown in FIG. an inclination sensor for detecting the inclination angle of a road surface; a determining means for determining whether the inclination angle detected by the inclination sensor is larger than a predetermined angle; a control means for operating a switching mechanism to set four-wheel drive; a rain detection means for detecting a rainy state; and when the rainy detection means detects a rainy state, the determination by the determination means is likely to be affirmative. The present invention is characterized by comprising a correction means for correcting the direction.

[Effect]

According to the above configuration, when traveling on a slope, the ftJ of the slope is
An inclination sensor detects an inclination angle, and when the inclination angle is equal to or greater than a predetermined angle, a 2-4 wheel drive switching mechanism switches to 4-wheel drive. In addition, when it rains, the rain detection means detects the condition to facilitate switching to four-wheel drive when traveling on a slope.

〔Effect of the invention〕

Therefore, it is possible to appropriately switch to four-wheel drive when driving on a slope in the rain.

〔Example〕

Embodiments of the present invention will be described below.

FIG. 2 is a configuration diagram showing one embodiment of the front wheel drive system.
This is applied to vehicles that switch between four-wheel drives. In this figure 2, 1 is a front wheel sensor that generates rotation pulses according to the rotation speed of the front wheels, 2 is a rear wheel sensor that generates rotation pulses according to the rotation speed of the rear wheels, and 3 is a sensor that detects rain conditions and detects rain. A rain sensor 4 generates a rain signal upon detection, and a tilt sensor 4 generates a tilt angle signal corresponding to the tilt angle of the road surface. 5 is a microcomputer with a built-in A/D converter, which executes the arithmetic processing for switching between 2-wheel drive and 4-wheel drive shown in Fig. Generates a command. 6 is a 2-4 wheel drive switching mechanism which switches to 2 wheel drive or 4 wheel drive in response to a 2 wheel drive command or a 4 wheel drive command from the microcomputer 5;
No. 21 Publication No. 1 [Those not shown can be used.

The operation of the above configuration will be explained with reference to the calculation flowchart shown in FIG.

Now, in a vehicle equipped with the components shown in FIG. 2, when a key switch is turned on at the start of operation, each part of the electrical system is activated by receiving voltage from the on-vehicle battery. In the microcomputer 5, after performing various initial settings, the arithmetic processing shown in FIG. 3 is repeatedly executed.

In this repeated calculation, in step 101, the front wheel rotation speed VF and the rear wheel rotation speed ■6 are calculated based on the rotation pulses from the front wheel rotation sensor 1 and the rear wheel rotation sensor 2, and in step 102, the front wheel rotation speed V4 , VF due to rear wheel rotation speed ■8
The slip rate S is obtained by calculating /VR, and it is determined in step 103 whether the slip rate S is greater than or equal to a predetermined value α.

The slip rate is S when the road surface is slippery such as snow.
is a value greater than or equal to α, the determination in step 103 is YES.
, proceed to step 104 and set the 4-wheel drive command to 2-4.
This occurs in the wheel drive switching mechanism 6. Therefore, the 2-4 wheel drive switching mechanism 6 performs a switching operation to 4 wheel drive. After the four-wheel drive command is issued, the microcomputer 5 executes the arithmetic processing in steps 105 and 106 and enters a standby state for a certain period of time, so that the four-wheel drive state continues.

On the other hand, when the determination in step 103 is No, the process proceeds to step 107 where the slope angle θ (θ is a positive value on an uphill slope, and θ is a negative value on a downhill slope) is manually determined based on the signal from the inclination sensor 4. do. Then, in the next step 10, if it is raining based on the signal from the rain sensor 3, the process proceeds to step 109 and the inclination angle θ is corrected by θ=K·θ (K is a constant larger than 1). In step 110, it is determined whether the absolute value of the oblique angle θ is greater than or equal to the predetermined angle β.

If the inclination angle θ is a large value in the positive or negative direction, the determination becomes YES, and the process proceeds to step 112, where a four-wheel drive command is generated to the 2-4 wheel drive switching mechanism 6. Further, when the absolute value of the slope angle is small, that is, the road is flat or a slope with a small slope, the determination in step 110 becomes No, and the process proceeds to step 111, where a 2-wheel drive command is issued to the 2-4 wheel drive switching mechanism 6. do. Therefore, the 2-4 wheel drive switching mechanism 6 performs a switching operation to 4-wheel or 2-wheel drive in response to a 4-wheel drive command or a 2-wheel vJ command.

In addition, in the above embodiment, when it rains, the inclination angle θ is multiplied by 4.
We have shown something that corrects the timing of switching to wheel drive, but
When rain is detected, the predetermined angle β may be made smaller to correct it.

Furthermore, although the rain sensor 3 is used to detect rainfall, the rain sensor 3 may be used to detect rainfall using a signal from a wipe pass inch.

[Brief explanation of the drawing]

1 is a block diagram showing the structure of the present invention, 2M is a block diagram showing an embodiment of the present invention, and FIG. 3 is a calculation flowchart showing the calculation process of the microcomputer in FIG. Representative Patent Attorney Takashi Okabe Figure 1 Figure 2

Claims (1)

[Claims] A 2-4 wheel drive switching device equipped with a 2-4 wheel switching mechanism that selectively switches between 2-wheel drive and 4-wheel drive, comprising: an inclination sensor that detects the inclination angle of a running road surface; determining means for determining whether or not the tilt angle detected by the tilt sensor is larger than a predetermined angle; and control for operating the 2-4 wheel switching mechanism to switch to 4-wheel drive when the determination result of the determining means is affirmative. 2-4 wheels, comprising: a rain detecting means for detecting a raining state; and a correcting means for correcting the determination of the determining means in a direction that tends to be positive when the rain detecting means detects a rainy state. Drive switching device.