JPS61263815A - Electronic control suspension device - Google Patents

Abstract

PURPOSE:To make proper roll control performable even at the times of sudden turning at low speed and slow turning at high speed, by finding a valve driving time with a map varying according to size of a steering wheel angular velocity, while controlling the feed and discharge of a fluid flowing in a fluid spring chamber. CONSTITUTION:A device bearing the above caption is provided with suspension units FS1, FS2, RS1 and RS2 (hereinafter referred to as S) at each wheel. Each unit S performs level control operation and, in turn, controls the extent of roll displacement in a car body in a way of controlling the feed and discharge of air to a main air spring chamber 7 by a control unit 37. In this case, when the angular velocity of a steering wheel 42 detected by a steering sensor 41 is more than the threshold value, a control time is found from a car speed- steering wheel angular velocity map on the basis of output of a car speed sensor 38, while when the steering wheel angular velocity is less than the threshold value, the control time is found from a G sensor map on the basis of output of a G sensor 39 detecting acceleration in both directions to be added to the car body. And, according to the control time found, charging and exhaust valves 20, 24 and 28, 31 are all controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronically controlled suspension system that uses a steering wheel angular velocity and a G sensor as roll displacement detection means to suppress roll displacement of a vehicle body during turning.

[Technical background of the invention and its problems] An electronically controlled suspension device has been proposed that improves ride comfort and handling stability by electronically controlling the damping force of a shock absorber and the spring constant of an air spring. ing. This kind of electronically controlled suspension system has a suspension with an air spring chamber for each wheel, and compressed air is supplied from the reserve tank to the air spring chamber by opening the air supply valve, or air is supplied by opening the exhaust valve. For example, roll control during turning is performed by exhausting compressed air from the spring chamber to the exhaust pipe. When performing such roll control, it is also possible to provide a steering wheel angle sensor that detects the steering wheel angle, and to start the roll control when the steering wheel angle detected by the steering wheel angle sensor exceeds a predetermined value. However, if O-roll control is performed based only on the steering wheel angle sensor, there is a drawback that the amount of roll control is insufficient for sharp turns at low speeds.

[Object of the Invention] The present invention has been made in view of the above points, and its object is to suppress the roll displacement of the vehicle body when turning by using the steering wheel angular velocity and G sensor as roll displacement detection means, and to prevent the roll displacement of the vehicle body when turning. However, it is an object of the present invention to provide an electronically controlled suspension device that can perform appropriate roll control even when turning at high speed and slowly.

[Summary of the Invention] A suspension unit provided for each wheel and each having a fluid spring chamber, a fluid supply means capable of supplying fluid to the fluid spring chamber of each suspension unit via a supply on-off valve, and each suspension unit. a fluid discharge means capable of discharging fluid from each of the fluid spring chambers via discharge on-off valves, and a supply on-off valve of the fluid spring chamber on the compression side of each of the suspension units with respect to the roll direction of the vehicle body when a roll occurs. A set amount of fluid is supplied to the fluid spring chamber by opening the fluid spring chamber for a controlled time, and a set amount of fluid is discharged from the fluid spring chamber by opening the discharge opening/closing valve of the fluid spring chamber on the extension side for a controlled time. A suspension device equipped with a roll displacement suppressing means for suppressing roll displacement of the vehicle, a vehicle speed-steering wheel angular velocity map storing a control time determined from the vehicle speed-steering wheel angular velocity, and a control determined by the left-right acceleration applied to the vehicle body. A G sensor map for storing time is provided, and when the steering wheel angular velocity is above a threshold value, the control time is obtained from the vehicle speed-steering wheel angular velocity map, and when the steering wheel angular velocity detected by the steering wheel angular velocity detecting means is smaller than the threshold value, the G sensor map is provided. By selectively obtaining the control time from the sensor map, appropriate roll control can be achieved in both low-speed sharp turns and high-speed slow turns.

[Embodiment of the Invention] An electronically controlled suspension device according to an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, air suspension unit FS1.
FS2. Since R81 and R82 each have substantially the same structure, the air suspension unit will be described below using the symbol S, unless the front and rear suspension units are specifically explained.

That is, the air suspension unit S incorporates a strut type shock absorber 1, and this shock absorber 1 is slidably inserted into a cylinder 2 attached to the front or rear wheel side. The cylinder 2 moves up and down with respect to the piston rod 4 in response to the up and down movement of the wheels, thereby making it possible to effectively absorb shock.

By the way, 5 is a damping force switching valve, and the rotation of this damping force switching valve 5 is controlled by an actuator 5a, and a first damping chamber 6a and a second damping chamber 6b are connected to an orifice a1.
The choice is made whether to communicate only through the orifices a1 and a2 (hard state) or through both orifices a1 and a2 (soft state). Note that the actuator 5a
The drive is controlled by a control unit 37, which will be described later.

Incidentally, a main air spring chamber 7 that also serves as a vehicle height adjustment fluid chamber is disposed coaxially with the piston rod 2 in the upper part of the shock absorber 1, and a bellows is installed in a part of the main air spring chamber 7. 8, the piston rod 4 can be moved up and down by supplying and discharging air to the main air spring chamber 7 through the passage 4a provided in the piston rod 4.

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 9a facing upward, and the outer wall of the main air spring 7 is provided with a spring receiver 9b facing downward.
A coil spring 10 is loaded between these spring receivers 9a and 9b.

Thus, 11 is a compressor. This compressor 11 compresses the atmospheric air sent from the air cleaner 12 and supplies it to the dryer 13. The compressed air dried with silica gel etc. in the dryer 13 is sent to the high pressure in the reserve tank 15 via the check pulp It is stored in the side reserve tank 15a. This reserve tank 15 is provided with a low pressure side reserve tank 15b. A compressor 1 driven by a compressor relay 11 is installed between the reserve tanks 15a and 15b.
6 is provided.

Further, a pressure switch 18 is provided which is turned on when the pressure in the low-pressure side reserve tank 15b becomes higher than atmospheric pressure. When the pressure switch 18 is turned on, the compressor relay 17 is driven. As a result, the reserve tank 15b is always kept below atmospheric pressure. The route by which compressed air is supplied from the high-pressure side reserve tank 15a to the suspension unit S is indicated by a solid arrow. In other words, the above reserve tank 15
The compressed air from a is supplied to the air supply flow rate control pulp 19.a, which is composed of a three-way valve, which will be described later. Front wheel air supply solenoid pulp 2G, check pulp 21. Solenoid pulp 2 for front 6
2° Suspension unit FS2 for the front 6 via the solenoid pulp 23 for the front clothing. It is sent to the front left suspension unit FSI. Also,
Similarly, the compressed air from the reserve tank 15a is supplied to the air supply flow rate control pulp 19, which is composed of a three-way valve to be described later. Rear wheel air supply solenoid pulp 24° check pulp 25. The rear fabric suspension unit R is connected to the rear fabric suspension unit R via the rear fabric solenoid pulp 26 and the rear clothing solenoid pulp 27.
82, sent to suspension unit R8I for rear clothing. Note that the downstream side of the check pulp 21 and the downstream side of the check pulp 25 are connected via a check pulp 211. On the other hand, the exhaust route from the suspension unit S is indicated by a broken line arrow. In other words, suspension unit FS1. The exhaust from the FS2 is sent to the low pressure side reserve tank 15b via the solenoid pulp 22, 23, the front exhaust pulp 28, and the residual pressure valve 29. Furthermore, suspension unit FS1. Exhaust from the FS2 goes through solenoid pulps 22, 23, front exhaust pulp 28, dryer 13. Exhaust solenoid pulp 30. It is released to the atmosphere via the air cleaner 12. In addition, the exhaust from the suspension units R81 and R82 includes the solenoid pulps 26 and 27, the rear exhaust pulp 31, and the residual pressure valve 32.
The water is sent to the low pressure side reserve tank 15b via the above.

Note that when the pressure in the reserve tank 15b is lower than the pressure in the main air spring chamber 3, the residual pressure valves 29 and 32 are opened, and when the pressure in the reserve tank 15b is higher than the pressure in the main air spring chamber 3, the residual pressure valves 29 and , 32 are in a closed state. Further, the exhaust from the suspension unit R81°R82 is supplied to the solenoid pulp 26,27, the rear exhaust pulp 31, the dryer 13. Exhaust solenoid pulp 30. It is released to the atmosphere via the air cleaner 12. Further, 33 is a pressure switch provided in a communication path communicating with the rear main air spring M3, and its operation signal is output to a control unit to be described later.

Further, 34 is a vehicle height sensor, and this vehicle height sensor 34 is attached to the 07 arm 35 of the front right suspension of the vehicle and detects the front vehicle height of the vehicle, and the rear left suspension of the vehicle is a front vehicle height sensor 34F. The rear vehicle height sensor 34R is attached to the lateral rod 36 of the vehicle to detect the rear vehicle height of the vehicle, and detection signals are supplied from these vehicle height sensors 34F134R to the control unit 37.

Each of the sensors 34F and 34R in the vehicle height sensor 34 is adapted to detect the distance from the normal vehicle height level, the low vehicle height level, or the high vehicle height level, respectively.

Further, the speedometer has a built-in vehicle speed sensor 38, which detects the vehicle speed and supplies the detected signal to the control unit 31.

In addition, for example, a left and right differential transformer type G sensor 39 is used as a vehicle body posture sensor that detects changes in the posture of the vehicle body.
An acceleration sensor is provided to detect acceleration in the longitudinal direction. The output voltage V of this G sensor 39 increases as the acceleration G increases, and an example of the output voltage is shown in FIG. 4. Further, the time differential value of the voltage V becomes a value proportional to the steering wheel angular velocity or the brake depression speed.

Reference numeral 40 denotes an indicator for displaying oil pressure, and the display of this indicator 40 is controlled by the control unit 31. Further, 41 is a steering sensor that detects the rotational speed of the steering wheel 42, that is, the steering speed, and its detection signal is sent to the control unit 37.

Further, numeral 44 is an accelerator opening sensor (not shown) that detects the depression angle of an accelerator pedal of the engine, and its detection signal is sent to the control unit 37. Also,
45 is a compressor relay for driving the compressor 11, and this compressor relay 45 is controlled by a control signal from the control unit 37. Furthermore, 46 is a pressure switch that is turned on when the pressure in the reserve tank 15a falls below a predetermined value, and its output signal is output to the control unit 37. In other words,
When the pressure in the reserve tank 15a falls below a predetermined value, the pressure switch 46 is turned on, and the control unit 37
The compressor relay 45 is operated under the control of.

As a result, the compressor 11 is driven and compressed air is sent to the reserve tank 15a.
The internal pressure of 5a is made equal to or higher than a predetermined value. In addition, the above solenoid valve 20.22.23.24.2B, 27°30
The opening and closing of the valves 19, 28, and 31 are controlled by control signals from the control unit 37.

In addition, the solenoid valves 22, 23, 26, 27 and valves 19, 28, 31 are three-way valves, and the second
The two states are shown in Figure 2. FIG. 2(A) shows a state in which the three-way valve is driven, and in this state compressed air moves along the path indicated by arrow A.

On the other hand, FIG. 2 (8) shows a state in which the three-way valve is not driven, and in this state compressed air moves along the path indicated by arrow B. Also, solenoid valve 20.24.3
0 consists of a two-way valve, and for its two states the fourth
Figure 3 (A) shows a state in which the solenoid valve is driven, and in this state compressed air moves in the direction of arrow C.On the other hand, when the solenoid valve is not driven, the As shown in Figure 3 (B), in this case there is no flow of compressed air.

Next, the operation of one embodiment of the present invention configured as described above will be explained. When the ignition key switch is turned on, the process of the flowchart shown in FIG. 5 is started. First, in step 811, the steering wheel angular velocity eh1 in the control unit 37 is 0 in the left and right direction.
The area for storing 1 vehicle speed V is reset. Next, the time T for which the valve has already been driven is stored in the map memory.
m is reset (step 512). Then, the process proceeds to step 513, where it is determined whether the main air spring chambers 7 of the left and right suspension units are in communication with each other. Here, when the solenoid valves 22.23° 26, 27 are all off, the left and right main air spring chambers 7 are communicated with each other.
It is determined whether or not all are turned off, and if all are not turned off, all are turned off.

Next, vehicle speed sensor 38. Steering sensor 41, G sensor 39
The vehicle speed V1, the steering wheel angular velocity eh1, and the left-right acceleration G detected in are read into the control unit 37 (step 514). Then, the process proceeds to step S15, where it is determined whether the acceleration G>O detected in step 814 is satisfied. Here, if rG>0'', it is determined that the vehicle is turning to the right, and if rG<OJ, it is determined that the vehicle is turning to the left. Hereinafter, a right turn will be explained as an example. In the case of such a right turn, the process proceeds to step 816, where it is determined whether the steering direction of the steering wheel is clockwise. This step 8
In the determination No. 16, it is determined whether the steering wheel angular velocity eh detected by the steering sensor 41 is positive or negative. Here, if it is determined that the steering direction is clockwise, that is, it is determined that the turn is to the right and the steering wheel is turned to the turning side, the process proceeds to step 817, where the current vehicle speed and steering wheel angular velocity are It is determined whether or not the threshold value shown in the figure is greater than or equal to the threshold value shown in the figure. That is, it is determined whether the current vehicle speed and steering wheel angular velocity belong to region A of the map shown in FIG. In this step S17, rY
When EsJ is determined, the vehicle speed-steering wheel angular velocity map shown in FIG. 7 is referred to, and it is detected in which region the point indicated by the current vehicle speed-steering wheel angular velocity is located, and the valve drive time Tp corresponding to that region is determined. Calculated. On the other hand, if rNOJ is determined in step 317, the G-sensor map shown in FIG. 8 is referred to and the valve driving time fllTp corresponding to the current left-right acceleration is calculated. When the valve driving time Tp is calculated by the processing in step 818 or 819, the process proceeds to step 820, where the control time 111T-Tp-Te is calculated. Since it is set to Tg+ -0 by default, it becomes T-Tp.
. Next, the process proceeds to step 821, where it is determined whether rT>0. Here, if rT>OJ, the process advances to step S22, and a command for the control time T is issued. That is, in the roll control shown in FIG. 9, the valve marked O in the right turn "start" mode is driven for the control time T, and compressed air is exhausted from the main air splash chamber 7 of the right suspension unit. Compressed air is supplied to the main air spring chamber 7 of the left suspension unit. Here, by driving the solenoid valves 22 and 28, communication between the left and right main air spring chambers 7 of the front and rear suspension units is cut off. Thereby, the right suspension unit and the left suspension unit can be supplied and discharged from the main air spring chamber 7 independently. Therefore, the vehicle height on the right side of the vehicle body is biased to decrease, and the vehicle height on the left side of the vehicle body is biased in a direction to increase. As a result, the vehicle body is controlled to be horizontal when turning to the right. Then, when the valve is driven for the control time T, the mode shifts to the "hold" mode, the front exhaust valve 28 and the rear exhaust valve 31 are driven, and compressed air is exhausted from the main air spring chamber 7 of the suspension unit. The state is maintained by prohibiting the use of

The process then proceeds to step 823, where the map memory is updated. That is, Ti-Tl). Thereafter, the process returns to step 814, and the vehicle speed V and the steering wheel angular velocity eh1 and the lateral acceleration G are read into the control unit 37 again. If the steering wheel is being operated further to the right, the process proceeds to steps s15iy and to, and the vehicle speed-steering wheel angular velocity map in FIG. 7 is referred to again to calculate the driving time Tp. Here, the drive time Tp calculated this time is the drive time fllTp calculated last time.
If it is the same, the control time f calculated in step 820
It becomes JT-0.

Therefore, rNOJ is determined in step 821, and the process returns to step 314 described above.

On the other hand, if the drive time calculated this time is greater than the drive time To calculated last time, the control time filT calculated in step 820 becomes a positive number.

Therefore, rYEsJ is determined in step S21, and the process proceeds to step 822. That is, step 8
22 and S23, additional roll control is performed. Then, in step S23, the map memory is updated, and the process returns to step S14.

If the steering wheel is turned from the rightward direction to the leftward direction, rNOJ is determined in step 816, and the process proceeds to step 824. In this step 824, the vehicle speed on the return side minus the steering wheel angular velocity is calculated as the first
It is determined whether or not it is equal to or greater than the threshold value in Figure 0. In other words, it is determined whether the vehicle speed-steering wheel angular velocity when the steering wheel is returned belongs to region B in FIG. For example, if you suddenly return the handle, it will enter the area. Therefore, in this case, the fluid springs of the left and right suspension units are communicated with each other. In other words, the "hold" mode in Figure 9 shifts to the "release" mode, but since all pulp is turned off,
- The main air spring chambers 7 of the left and right suspension units are communicated with each other, the left and right main air spring chambers 7 are made to have the same pressure, and roll control is released. In this manner, when the steering wheel is suddenly returned after performing the roll control, the O-roll control is quickly released to ensure safety.

On the other hand, if rNOJ is determined in step 824, the process proceeds to step 826, where it is determined whether IG+<0.3. In this step 826, rYEsJ
If it is determined that this is the case, the process proceeds to step 825 and the roll control is canceled. If the determination in step S26 is "NO", the process advances to step 827 and the vehicle speed V≦20KI is determined.
It is determined whether or not it is I/h. This step 827
Even if it is determined that rYEsJ occurs in step 825, the process proceeds to step 825 and the roll control is canceled. Thereafter, the process proceeds to step S14 and again the vehicle speed V1 is the steering wheel angular velocity eh.
, the acceleration G in the left and right direction is read into the control unit 37. By the way, when the process of step 825 is completed, the process returns to step 812 and the map memory is reset. Thereafter, the processing from step 813 onwards is repeated.

The above operation describes roll control when the steering wheel is steered to the right and the vehicle body turns to the right. However, when the steering wheel is steered to the left and the vehicle body is turned to the left, step 81
rNOJ at step 5, and 'NOJ' at step 828.
” is determined, and the process proceeds to step S11. Since the processing from step 817 onward is the same as that for the right turn described above, detailed explanation thereof will be omitted. In other words,
The process performed in step 822 is the pulp opening/closing of the "start" mode and "hold" mode of the left turn shown in FIG.

If the steering wheel is turned back after turning to the left, it is determined that the steering wheel is rYEsJ in step 828, and the processing from step 824 onward is performed.
When the conditions for canceling roll control are met, roll control is canceled.

As described above, since the valve driving time Tp is selected based on the judgment in step 817, when the steering wheel is turned suddenly, the pulp driving time Tp is obtained from the vehicle speed-steering wheel angular velocity map, and when the steering wheel is turned gently, the pulp driving time Tp is obtained from the vehicle speed - steering wheel angular velocity map. When the acceleration G in the left and right direction exceeds a predetermined value, the fl1Tp during pulp drive is determined using the G map, so that optimal roll control can be performed in both low-speed sharp turns and high-speed slow turns. Furthermore, since the G sensor is used instead of the steering wheel angle sensor, reliability can be improved.

[Effects of the Invention] As detailed above, according to the present invention, the roll displacement of the vehicle body during turning is suppressed by using the steering wheel angular velocity and the G sensor as a roll displacement detection means, and the roll displacement of the vehicle body during turning is suppressed, making it suitable for both low-speed sharp turns and high-speed slow turns. Therefore, it is possible to provide an electronically controlled suspension device that can perform accurate roll control.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an electronically controlled suspension device according to an embodiment of the present invention, Fig. 1!1 (A) and (B) are diagrams showing the driving and non-driving states of the three-way valve, and Fig. 3 is a diagram showing the solenoid. Figure 4 shows an example of the output voltage of the G sensor; Figure 5 shows the operation of the same embodiment; Figure 6 shows the vehicle speed in the vehicle speed-steering wheel angular velocity coordinate. - A diagram showing the range of use of the steering wheel angular velocity map or the usage range of the G sensor map, Figure 7 is a diagram showing the vehicle speed-steering wheel angular velocity map, Figure 8 is a diagram showing the G sensor map, and Figure 9 is a diagram showing the vehicle height adjustment and attitude control. Diagram showing pulp opening and closing, No. 10
The figure is a diagram showing areas where left and right main air springs communicate and areas where they do not communicate in a vehicle speed-handle angular velocity coordinate. 5a...actuator, 11...compressor,
15... Reserve tank, 19... Air supply flow rate control pulp, 20... Air supply solenoid pulp for front wheels, 24.
...Air supply solenoid pulp for rear wheels, 28...Front exhaust pulp, 31...Rear exhaust pulp. Applicant's agent Patent attorney Takehiko Suzue Figure 14

Claims (1)

[Claims] A suspension unit provided for each wheel and having a fluid spring chamber, a fluid supply means capable of supplying fluid to the fluid spring chamber of each suspension unit via a supply on/off valve, and each fluid spring chamber of each suspension unit. a fluid discharge means capable of discharging fluid from each of the suspension units through discharge on-off valves, and by opening the supply on-off valves of the fluid spring chambers on the contraction side of each of the suspension units for a controlled time with respect to the roll direction of the vehicle body when a roll occurs. By supplying a set amount of fluid to the fluid spring chamber and opening the discharge on-off valve of the fluid spring chamber on the extension side for a controlled period of time, a set amount of fluid is discharged from the fluid spring chamber, thereby suppressing roll displacement of the vehicle body. A suspension device comprising: a steering wheel angular velocity detecting means for detecting a steering wheel angular velocity; a vehicle speed detecting means for detecting a vehicle speed; a G sensor for detecting horizontal acceleration applied to the vehicle body; A vehicle speed-steering wheel angular velocity map that stores the control time determined from the angular velocity, a G sensor map that stores the control time determined by the horizontal acceleration applied to the vehicle body, and a steering wheel angular velocity detected by the steering wheel angular velocity detection means. control time selection means that obtains a control time from the vehicle speed-steering wheel angular velocity map when the steering wheel angular velocity is greater than a threshold value, and obtains a control time from the G sensor map when the steering wheel angular velocity detected by the steering wheel angular velocity detection means is smaller than the threshold value; An electronically controlled suspension device characterized by: