JPH035461Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is a drive state switching device for a four-wheel drive vehicle that can automatically switch from two-wheel drive to four-wheel drive without relying on the driver's judgment. Regarding.

Conventional technology When driving on slippery roads such as snowy roads or frozen roads (low-friction roads), or roads with high running resistance such as sandy roads, steep slopes, and muddy roads (uneven roads), driving power is transmitted to all wheels. It is known that four-wheel drive vehicles are advantageous in terms of maneuverability and driving stability. A four-wheel drive vehicle that can switch between a two-wheel drive state and a four-wheel drive state as necessary is equipped with a transfer for switching the drive state and an actuator for operating the transfer. The vehicle was configured to select the driving state based on the situation and manually switch the state.

Problems to be Solved by the Invention However, in the conventional four-wheel drive vehicle described above, it is difficult to select between two-wheel drive state and four-wheel drive state.
Since the decision to switch is left to the driver, the decision to switch may vary depending on the driver's experience and skills. For this reason, even when it is preferable to drive in four-wheel drive, the vehicle may continue to drive in two-wheel drive, making it impossible to fully demonstrate its capabilities as a four-wheel drive vehicle. Also,
Manual switching operations are cumbersome for the driver, and there has been a desire for countermeasures that will allow the driver to utilize these functions easily and reliably.

The present invention was devised in view of the above-mentioned problems, and its purpose is to automatically change the driving state of a four-wheel drive vehicle without relying on the driver's judgment. An object of the present invention is to provide a switching device.

Means for Solving the Problems The present invention solves the above-mentioned problems, and is a four-wheel drive system equipped with a transfer that can switch between a two-wheel drive state and a four-wheel drive state, and an actuator that switches and operates the transfer. In wheel drive vehicles,
angular velocity detection means for detecting the operating angular velocity of the steering wheel; angular velocity detection means for determining whether the angular velocity detected by the angular velocity detection means is greater than or equal to a predetermined value; A counting means for counting the number of occurrences, a vehicle speed detecting means for detecting the vehicle speed of the four-wheel drive vehicle, and a vehicle speed determining means for determining whether the vehicle speed detected by the vehicle speed detecting means is equal to or higher than a predetermined speed. According to the signals from each of the above means, when the number of occurrences of angular velocity equal to or greater than the predetermined value within the predetermined time is equal to or greater than the predetermined number of times, and when the vehicle speed when the angular velocity equal to or greater than the predetermined value is detected is equal to or greater than the predetermined vehicle speed, This is a drive state switching device for a four-wheel drive vehicle, characterized by comprising a control device that operates an actuator to put a transfer in a four-wheel drive state.

Effect: According to the above-mentioned means, the steering operation angular velocity and vehicle speed are constantly detected while the vehicle is running, and the driving situation of the vehicle is determined based on the detection results, so that when it is determined that four-wheel drive is appropriate, the transmission is activated. By operating the actuator for four-wheel drive, the transfer can be automatically switched to four-wheel drive.

Embodiment An embodiment of the drive state switching device for a four-wheel drive vehicle according to the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a block diagram showing the configuration of the drive state switching device, in which a steering wheel angular velocity sensor 1 is provided as angular velocity detection means for detecting the operating angular velocity of the steering wheel. As the steering wheel angular velocity sensor 1, for example, one having a structure in which two photo interrupters are arranged side by side can be used, and a pulse signal of angular velocity corresponding to the steering wheel operating direction is outputted to the calculating means 3 via the operating direction identifying means 2, and then The signal of the steering wheel angular velocity calculated in is sent to the steering wheel angular velocity determining means 4. The steering wheel angular velocity determining means 4 determines that the input steering wheel angular velocity has reached a stored constant reference value or more,
The signal is output to a counter 6 provided as a counting means. The counter 6 counts input signals when the steering wheel angular velocity becomes equal to or higher than the reference value within a certain period of time measured by the timer 5. When this input signal is counted a predetermined number of times or more, the counter 6 sends a signal to the control device 7 to control the four wheels. A switching signal to drive is output.

Further, in parallel with the detection of the steering wheel angular velocity by the steering wheel angular velocity sensor 1, a vehicle speed sensor 8 provided as a vehicle speed detection means detects the vehicle speed of the own vehicle. The vehicle speed sensor 8 outputs the vehicle speed as a pulse signal to the calculation means 9, and the signal processed by the calculation means 9 is sent to the vehicle speed determination means 10. This vehicle speed determination means 1
0, it is determined that the input vehicle speed has reached a stored constant reference value or higher, and the signal thereof is output to the output determining means 11. Furthermore, a signal indicating that the steering wheel angular velocity has exceeded the reference value is input from the counter 6 to the output judgment means 11, and even if the steering wheel angular velocity has not detected a value greater than or equal to the reference value for more than the reference number of times within the reference time. Even in such a case, a switching signal to four-wheel drive is outputted from the output determining means 11 to the control device 7 at the time when both the detected steering wheel angular velocity and vehicle speed exceeding the reference value are input.

As described above, when a switching signal to four-wheel drive is input to the control device 7, the solenoid 21 is energized and the actuator 12 switches the transfer.
is activated, the four-wheel drive switching clutch (transfer) 13 is switched to the four-wheel drive state, and the propeller shaft 14 is rotated. Therefore, the driving force of the engine 20 is transmitted from the propeller shaft 14 to the rear wheels 16 via the rear differential 15, and is transmitted to all wheels together with the front wheels 18 to which the driving force is transmitted via the front differential 17. It becomes a four-wheel drive vehicle. Note that in this embodiment, the second
As shown in the figure and FIG. 3, operation direction identification means 2,
A calculating means 3, a steering wheel angular velocity determining means 4, a timer 5, a counter 6, a control device 7, a calculating means 9, a vehicle speed determining means 10, and an output determining means 11 are integrated into the controller C, and 19 is a direction changer. showing the machine.

Next, the operation will be explained based on the flowchart shown in FIG. While the four-wheel drive vehicle equipped with the drive state switching device described above is running, the detected values of the steering wheel angular velocity sensor 1 and the vehicle speed sensor 8 are constantly sent to the controller C. The controller C first monitors the steering wheel angular velocity θ, and detects a relatively rapid steering operation when θ exceeds a predetermined value (for example, 200 deg/sec). This relatively rapid steering operation is performed a predetermined number of times (for example, 2 times) within a predetermined short time (for example, 5 seconds).
(times) or more, it is determined that traveling in four-wheel drive mode is preferable, and the transfer is automatically switched to four-wheel drive mode. Furthermore, even if relatively rapid steering operations are not performed more than a predetermined number of times within a predetermined short period of time, relatively rapid steering operations may occur at relatively high vehicle speeds (for example, 40
Km/h), the system determines that it is preferable to drive in four-wheel drive mode, and automatically switches the transfer to four-wheel drive mode.

Therefore, in driving situations where the vehicle speed is low but requires complicated steering operations to maintain driving stability, such as when driving on rough terrain, the system automatically switches from two-wheel drive to four-wheel drive. Also, if you suddenly change lanes while driving at relatively high speeds, the system automatically switches from two-wheel drive to four-wheel drive, so the drive power is distributed to the four wheels. This enables stable driving with less slippage on the road surface.

Effects of the invention According to the drive state switching device for a four-wheel drive vehicle according to the present invention described above, switching from two-wheel drive to four-wheel drive is automatically performed according to the driving state without relying on the driver's judgment. Therefore, the ability of the four-wheel drive vehicle can be fully utilized to ensure running stability.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the drive state switching device for a four-wheel drive vehicle according to the present invention. Figure 1 is a block diagram showing the configuration of the controller, and Figure 2 is a block diagram of the four-wheel drive mechanism. FIG. 3 is a system diagram showing an overview of the drive state switching device, and FIG. 4 is a flowchart showing the control of the controller. DESCRIPTION OF SYMBOLS 1... Handle angular velocity sensor (angular velocity detection means), 4... Steering wheel angular velocity determination means, 5... Timer, 6... Counter (counting means), 7... Control device (4WD switching), 8... Vehicle speed sensor ( vehicle speed detection means), 10... vehicle speed determination means, 11... output judgment means, 12... actuator, 13...
4WD switching clutch (transfer), 14... propeller shaft, 21... solenoid.

Claims (1)

[Scope of utility model registration request] In a four-wheel drive vehicle equipped with a transfer that can switch between a two-wheel drive state and a four-wheel drive state, and an actuator that switches and operates the transfer, an angular velocity detection means for detecting an operating angular velocity of a steering wheel; angular velocity determination means for determining whether the angular velocity detected by the detection means is equal to or greater than a predetermined value; a counting means for counting the number of occurrences of an angular velocity equal to or greater than the predetermined value within a predetermined time; A vehicle speed detection means for detecting the vehicle speed, a vehicle speed determination means for determining whether the vehicle speed detected by the vehicle speed detection means is equal to or higher than a predetermined speed, and a predetermined value within the predetermined time based on signals from each of the above means Control that activates the actuator to put the transfer gear in a four-wheel drive state when the number of occurrences of the above angular velocity is a predetermined number or more, and when the vehicle speed when the angular velocity above a predetermined value is detected is a predetermined vehicle speed or more. A drive state switching device for a four-wheel drive vehicle, characterized by comprising a device.