JPS61263821A - Turnover preventive device for truck at running zigzag - Google Patents

Abstract

PURPOSE:To prevent a truck from turning sideways in an effective manner, by processing a detection signal on transverse acceleration in the truck at two detecting parts, while detecting an S-shaped running state subject to dangerousness for a turnover highly accurately and altering the damping constant of a suspension. CONSTITUTION:An acceleration relative physical value detecting device 10, which detects a physical value S1 related to trabsverse acceleration in a truck, is installed, and when an absolute value of this physical value S1 becomes more than a first reference value, a detection signal S2 is outputted from a first detecting part 20. And, at the time of generation of this signal S2, after the said absolute value becomes smaller than the first reference value,a direction of the said physical value is turned over within the specified time, and when the absolute value of this turned physical value becomes more than a second reference value, a detection signal S3 is outputted from a second detecting part 30. And, with this signal S3, the damping contestant of a suspension is controlled so as to be made larger by a damping constant control part 40, and according to output of this control part 40, the damping constant of the suspension 60 is controlled by a driving device 50.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rollover prevention device that prevents a truck from rolling over when traveling in an S-shape.

[Prior Art] Conventionally, a suspension with a variable damping constant is used to detect various physical quantities such as lateral acceleration, steering angle, vehicle speed, braking device operation, unbalanced weight, etc. A device is known that variably controls the damping constant of the suspension to improve running performance, steering performance, and ride comfort (Japanese Patent Laid-Open No. 5
7-182505, Japanese Unexamined Patent Publication No. 57-201707). However, these devices are not used to prevent trucks from rolling over, and do not solve the problem.

It is known that when a truck travels in an S-shape as shown in FIG. 5, it overturns near the second corner B even at relatively low vehicle speeds. This means that when turning a corner on a narrow road, S-shaped driving is also performed, as shown in Figure 6.
There is a possibility of rollover near the point.

The cause of this rollover is thought to be as follows. At the first corner A, the outer wheel side of the vehicle sinks due to centrifugal force,
A restoring force f is generated in the coil spring of the shock absorber. Further, at the next corner B, a sinking force F acts on the outer ring side Y, that is, the side Y opposite to the outer ring X in the case of corner A, due to the centrifugal force.

Here, when corner A and corner B are continuous and their period and the restoration period of the coil spring are synchronized with a predetermined phase relationship,
Near T-degree corner B, the tilting toward the Y side due to the reaction of the restoring force f of the coil spring generated at corner A and the tilting toward the Y side due to the sinking force F toward the opposite side Y due to centrifugal force have a synergistic effect. Then, near the 8th corner, the moment of rotation toward the outer wheel side Y becomes maximum due to the load, etc., and rollover occurs there.

[Problems to be Solved by the Invention] An object of the present invention is to prevent such overturning when a truck travels in an S-shape.

[Technical means for solving the problem] FIG. 1 is a block diagram showing the concept of the present invention.

The present invention includes an acceleration-related physical quantity detector mio that detects a physical quantity (Sl) related to the lateral acceleration of a truck; When the first detection unit 2o outputs the detection signal (S2) and the first detection unit 20 outputs the detection signal (S2), the absolute value of the physical quantity becomes smaller than the first reference value. 12 detection unit 30 that outputs a detection signal (s3) when the direction of the physical quantity related to the lateral acceleration is reversed and the absolute value of the reversed physical quantity becomes larger than a 21st quasi-value within a predetermined time after the lateral acceleration; When the detection signal (s3) is output from the second detection unit 30, the damping constant of the suspension provided at least on the inner wheel side or the outer wheel side of the rotation of the truck is controlled to be thicker (S4). According to the output signal (S4) of the attenuation constant control section 40,
A drive device that changes the damping constant of the suspension 6o!
50; and a suspension 60 whose damping constant is changed by the drive device 150.

Here, the physical quantity related to acceleration directly indicates acceleration,
As the acceleration-related physical quantity detection device, an acceleration detection device that directly detects acceleration in the lateral direction can be used. others,
Indirectly, the physical quantity related to acceleration is lateral acceleration determined from the steering angle and vehicle speed, and the acceleration-related physical quantity detection device may use a steering angle detector and a vehicle speed detector.

Further, when a truck turns a corner, the speed is almost constant and low, so a steering angle can be used as the physical quantity related to acceleration, and a steering angle detector can be used as the detection device.

In the second test, the suspension that is controlled in accordance with the output signal from the mountain portion may be provided on at least one side of the suspension, but it is more effective if both sides are controlled.

To control the damping constant of the suspension, for example, as is well known, a hydraulic cylinder is used, and an electric proportional control valve is installed at a portion that bypasses both cylinder chambers divided by a piston, and its opening degree is electrically adjusted. A method of changing the damping constant by changing the fluid resistance may also be used.

[Operation] FIG. 2 is a characteristic diagram for explaining the operation of this device. When the truck travels in an S-shape, the lateral acceleration-related physical quantity 81 (simply referred to as "physical quantity") detected by the acceleration-related physical quantity detection device 10 changes in a curve as shown by the solid line in the figure. In the case of normal curve driving, the characteristics are shown by the broken line. The first detection unit 20 outputs a detection signal S2 at T1 when the physical quantity S1 reaches the first reference value SA. Second detection unit 3
0 is measured from time T2 when the absolute value of the physical quantity becomes smaller than the first reference value SA, and the sign of the physical quantity is reversed,
T when the absolute value of the physical quantity after reversal reaches the 12 reference value 8B
When the elapsed time up to 3 is smaller than the predetermined value TS, a detection signal @S3 is output at time T3. Attenuation constant control section 40
When inputting the signal @S3, Ill is input to the drive @@50.
By outputting the III signal S4, the drive device 150 increases the damping constant of the suspension 60. If you make the suspension on the outer wheel harder when turning the first corner A,
In the process of reaching the second corner B, the restoring force of the suspension is controlled, and it is possible to prevent the vehicle from sinking toward the outer wheel Y side when turning the second corner B. This means that even if the suspensions on the opposite side or both sides are operated in the same way, the same effect will be produced. As a result, it is possible to prevent the vehicle from rolling over due to the backlash of the vehicle near the 8th corner of the second corner.

[Example] The present invention will be described below based on a specific example.

FIG. 3 is a block diagram illustrating the configuration of an apparatus according to an embodiment of the present invention. In this embodiment, the easiest method to implement is to detect the steering angle of the steering shaft as a physical quantity related to lateral acceleration.

are doing. A photointerrupter 11 is disposed on a steering shaft 81 of a steering wheel 80 of the truck, and its output signal is input to a counter 12. The main control section of the device of this embodiment is realized by a computer system. That is, an interface 71 that inputs the steering angle signal of the counter 12, and a C interface that performs predetermined processing.
PU 72, ROM 74 that stores programs, RAM 75 that inputs and outputs data, and output interface 7
It consists of 3. The output signal of the output interface 73 is input to the driver 52, and the driver 52 outputs a drive signal to the solenoid 56 of the electric proportional control valve 54 disposed in the bypass line 62 of the cylinder 61 of the suspension. Adjust the opening. The bypass conduit 62 is a conduit that communicates the cylinder chambers 64 and 66, and one end of the suspension cylinder 61 and piston rod 63 are connected to the axle and the vehicle body (paths shown), respectively. The viscous resistance of the fluid changes according to the opening degree of the control valve provided in the bypass pipe 62, and the resistance of the relative movement between the piston rod 63 and the cylinder 61 changes, thereby changing the elastic constant of the suspension. I can do it.

Figure 4 shows the CPLI72 used in the same example device.
3 is a flowchart showing the processing of FIG. Furthermore, in this embodiment, the vertical axis in FIG. 2 will be read as the steering angle θ.

In step 100, various initial settings are performed.

F is a parameter that determines whether the steering angle has exceeded a certain angle; when the value is 0, the vehicle is running in a straight line, and when the value is 1, the vehicle is running on a curve. In step 102, the steering angle θ is read. In step 104, the absolute value of the steering angle is compared with the first reference value SA, and when it becomes larger than SA, the process moves to step 106 and the parameter F is set to 1. That is, the state of T1 in FIG. 2 has been detected. If not, the process proceeds to step 108, and the value of the parameter F is determined, and if it is not detected that the vehicle has been steered by a certain angle, the process returns to step 102, and the above-described process is repeated.

If the determination in step 108 is YES, it means that the state of T2 in FIG. 2 has been determined, and the process moves to step 110. In step 110, a subtraction timer t
Set the standard time TS to .

In step 112, the elapsed time of the timer is determined, and if the predetermined time has not elapsed, the process proceeds to step 114, where it is determined whether the sign of the steering angle θ has been reversed. If the steering angle is not reversed, the process returns to step 112, and if it is reversed, the process moves to step 116, where the absolute value of the steering angle is compared with the second reference value SB. When it becomes larger than 8B, it means that the state of T3 in Fig. 2 has been detected, and step 1
18, a signal for increasing the damping constant of the suspension is output to the driver 52. Further, when the value does not become larger than the second reference value SB, the process returns to step 112.

Eventually, in steps 112 to 116, the predetermined reference time 1! In IITS, the steering angle is set to the first reference value S.
Only when the value changes from A to the second reference value 8B, the damping constant of the suspension is set to a large value. If the above conditions are not met, it is assumed that the vehicle is traveling in an S-shape without overturning or is simply traveling on a curve, and the process proceeds to step 132, where parameter 1 is set to a straight traveling state, and the execution is repeated from step 102.

Next, if the damping constant of the suspension is set to be large, the process moves to step 120 and the steering angle θ is read. In step 122, the timer t is set to a constant value, and in step 124, it is determined whether the absolute value of the steering angle is within the constant range SC. If it is not within a certain range,
Assuming that the curve is still being driven, step 11
Return to step 8 and keep the damping constant of the suspension at a large value. If the steering angle is within a certain range, the process moves to step 126 and the elapsed time is determined. If it is determined by the loop of steps 124, 126, 130, and 124 that the absolute value of the steering angle is within a certain range SC for a certain period of time, it is determined as YES in step 126, and it is assumed that straight running has returned. As such, the damping constant of the suspension is returned to its original value in step 128, and the process returns to step 102 via step 132.

By detecting the steering angle using the method described above, S-shaped running is detected, and before a rollover occurs due to swinging back, the eggplant suspension is set hard to suppress the reaction (reaction caused by swinging back) and prevent rollover.

In the above embodiments, S-shaped running was determined based on the steering angle θ, but by adding the vehicle speed to this, the first and second
The reference value 5A18B and the predetermined time TS may be changed.

Also, by calculating the lateral acceleration from the steering angle and vehicle speed, and performing the same processing as described above for the lateral acceleration,
It is possible to detect the S-shaped running state of the truck.

[Effects of the Invention] As described above, the present invention provides an acceleration-related physical quantity detection device that detects physics related to the lateral acceleration of a truck, and an acceleration-related physical quantity detection device that detects a physical quantity related to the lateral acceleration of a truck; a first detection unit that outputs a detection signal; and when the first detection unit outputs the detection signal, the physical quantity is laterally detected within a predetermined time after the absolute value of the physical quantity becomes smaller than the first reference value; a second detection unit that outputs a detection signal when the direction of the physical quantity related to acceleration is reversed and the absolute value of the reversed physical quantity becomes larger than a second reference value; and when the detection signal is output from the second detection unit. a damping constant control unit that controls to increase a damping constant of a suspension provided at least on an inner wheel side or an outer wheel side of rotation of the truck;
It is characterized by comprising a drive device that changes the damping constant of the suspension according to the output signal of the damping constant υJtl11 section, and a suspension that changes the damping constant by the drive device.

Therefore, mainly by the first detection section and the second detection section, it is possible to accurately detect the 8B-shaped running state where there is a risk of rollover. Furthermore, when this condition is detected, the damping constant of the suspension is increased, so that the rolling back around the second curve of S-shaped travel is suppressed, and rollover is prevented.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the concept of the present invention, Fig. 2 is a characteristic diagram showing the change characteristics of physical quantities related to lateral acceleration when a truck travels in an S-shape, and Fig. 3 is a diagram showing an example device. The block diagram shown in Fig. 4 shows the configuration of
Flowcharts showing the processing of CPtJ used in the same device, FIGS. 5 and 6, are explanatory diagrams for explaining the swing back of the S-shaped running of the truck. 80...Steering wheel 81...Steering shaft 11...Photo interrupter 61...Cylinder 63...Cylinder rod 64.66...Cylinder chamber 62...Bypass conduit 54...Electric type Proportional control valve patent applicant: Nippondenso Co., Ltd. Agent Patent attorney: Makoto Okawa Patent attorney: Shudo Hizutani Patent attorney: Akio Maruyama

Claims (4)

[Claims] (1) An acceleration-related physical quantity detection device that detects a physical quantity related to the lateral acceleration of the truck, and outputs a detection signal when the absolute value of the physical quantity detected by the detection device exceeds a first reference value. a first detection section, and when the first detection section outputs the detection signal,
Thereafter, within a predetermined time after the absolute value of the physical quantity becomes smaller than the first reference value, the direction of the physical quantity related to the lateral acceleration is reversed, and the absolute value of the reversed physical quantity becomes larger than the second reference value. a second detection section that outputs a detection signal when the second detection section outputs a detection signal; a damping constant control section that controls the damping constant; a drive device that changes the damping constant of the suspension according to an output signal of the damping constant control section; and a suspension that changes the damping constant by the drive device. Device. (2) The truck overturn prevention device according to claim 1, wherein the acceleration-related physical quantity detection device is an acceleration detection device that detects acceleration in a lateral direction. (3) The physical quantity related to the acceleration in the lateral direction is a lateral acceleration determined from the steering angle and the vehicle speed, and the acceleration-related physical quantity detection device is characterized by comprising a steering angle detector and a vehicle speed detector. A truck rollover prevention device according to claim 1. (4) The truck rollover according to claim 1, wherein the physical quantity related to the lateral acceleration is a steering angle, and the acceleration-related physical quantity detection device comprises a steering angle detector. Prevention device.