JPH0314650B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a vehicle height adjustment function that can adjust the vehicle height to a desired value, and a vehicle height adjustment function that can adjust the posture changes that occur in the vehicle body such as roll displacement and pitching displacement. The present invention relates to a vehicle suspension device equipped with a posture control function that forcibly corrects the posture.

(Prior art) As a method of performing the above-mentioned roll control, a fluid spring chamber is provided for each wheel, and when traveling straight, the fluid spring chamber on the left wheel side and the fluid spring chamber on the right wheel side are communicated with each other so that they are not connected to each other. When maintaining the same pressure and executing roll control, communication between the fluid spring chamber on the left wheel side and the fluid spring chamber on the right wheel side is cut off, and at the same time, a set amount of fluid is supplied to the fluid spring chamber on the contraction side in the roll direction. At the same time, a method is known in which roll displacement of the vehicle body is suppressed by discharging a set amount of fluid from the fluid spring chamber on the extension side (US Pat. No. 2,950,124).

(Problem to be Solved by the Invention) In order to carry out such a method, it is necessary to control mutual communication and isolation between the fluid spring chamber on the left wheel side and the fluid spring chamber on the right wheel side, and to control the communication and isolation between the left and right wheel side fluid spring chambers. It is necessary to be able to control the supply of fluid to one fluid spring chamber and the discharge of fluid from the other fluid spring chamber. Therefore,
Problems arise such as an increase in the number of fluid flow paths and valves, and an accompanying complexity of the control system.

The present invention aims to solve these problems by reducing the number of flow channels and valves as much as possible.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention was devised in view of the above, and includes a fluid spring chamber provided for each wheel, and a fluid supply source connected to each fluid spring chamber. A fluid supply means for supplying fluid through the supply on-off valve, a fluid discharge means for discharging fluid from the fluid spring chamber via the discharge on-off valve, and each of the fluid spring chambers and the discharge on-off valve. A three-way valve for the left front wheel and a three-way valve for the right front wheel are respectively installed in between.
a three-way valve for the left rear wheel, a three-way valve for the right rear wheel, a front wheel side communication passage whose one end is connected to the three-way valve for the left front wheel and the other end to the three-way valve for the right front wheel, and one end of which is connected to the three-way valve for the right front wheel; The three-way valve for the left rear wheel is provided with a rear-wheel side communication passage whose other end is connected to the three-way valve for the right rear wheel, and the fluid supply means is configured such that the fluid that has passed through the supply on-off valve is connected to the three-way valve for the right rear wheel. The fluid spring chamber on the front wheel side is supplied through the front wheel side communication passage, and the fluid spring chamber on the rear wheel side is supplied through the rear wheel side communication passage. The valve has two positions, a first position in which each of the fluid spring chambers communicates with each of the communication passages, and a second position in which each of the fluid spring chambers communicates with the discharge on-off valve. It is composed of a switching type valve, and furthermore, between the supply on-off valve and the front wheel side communication passage and the above rear wheel side communication passage, only fluid flows from the supply on-off valve to each of the communication passages. A suspension device for a vehicle is characterized in that it is provided with check valves that permit the following.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. In Fig. 1, the air suspension units FS1, FS2, RS1, and RS2 each have almost the same structure. The system unit will be explained using the symbol S, and only the parts necessary for vehicle height control will be illustrated and explained.

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

Incidentally, an air spring chamber 3 serving as a vehicle height adjustment fluid spring chamber is arranged coaxially with the piston rod 2 in the upper part of the shock absorber 1.
A part of this air spring chamber 3 is formed by a bellows 4, so that by supplying and discharging air to the air spring chamber 3 through a passage 2a provided in the piston rod 2, the piston rod can be raised and lowered relative to the cylinder. It's getting old.

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 5a facing upward, and the outer wall of the air spring chamber 3 is provided with a spring receiver 5b facing downward. A coil spring 6 is loaded between them.

Next, a circuit for supplying and discharging compressed air in the air spring chamber 3 of each suspension unit S will be explained. Air is stored in a reserve tank 14 via a dryer 12 and a check valve 13 from a compressor 11 as a compressed air generator. In other words,
The compressor 11 compresses the atmospheric air sent from the air cleaner 15 and supplies it to the dryer 12, and the compressed air dried by silica gel or the like from the dryer 12 is stored in the reserve tank 14. The progress in which compressed air is supplied from the reserve tank 14 to the suspension unit S is shown by solid arrows. That is, the compressed air from the reserve tank 14 is supplied to the air supply solenoid valve 16 as a supply control valve, the check valve 17, and the two-position three-way valve 18.
Suspension unit FS via 1,182
1. Sent to FS2. Similarly, compressed air from the reserve tank 14 is supplied to the air supply solenoid valve 1.
6. It is sent to the suspension units RS1 and RS2 via the check valve 19 and two-position three-way valves 183 and 184. In addition, 100 is a front wheel side communication passage which is connected to the three-way valve 181 at one end and the three-way valve 182 at the other end, and is also connected to the air supply solenoid valve 16 via the check valve 17. This is a rear wheel side communication passage connected to the three-way valve 183 and the three-way valve 184 at the other end, and to the air supply solenoid valve 16 via the check valve 19.

On the other hand, the progress of the exhaust gas from the suspension unit S is indicated by broken line arrows. That is, the compressed air from the suspension units FS1 and FS2 is released to the atmosphere through the three-way valves 181 and 182, the dryer 12, the exhaust solenoid valve 20 as an exhaust control valve, the check valve 21, and the air cleaner 15. In addition, suspension unit RS1,
Compressed air from RS2 is supplied through three-way valves 183, 184,
It is released to the atmosphere via the dryer 12, exhaust solenoid valve 20, check valve 21, and air cleaner 15.

In addition, 22 is a vehicle height sensor, and this vehicle height sensor 2
2 is a front vehicle height sensor 22F that is attached to the lower arm 23 of the front right suspension of the automobile to detect the front vehicle height of the automobile, and a front vehicle height sensor 22F that is attached to the lateral rod 24 of the rear left suspension of the automobile to detect the rear vehicle height of the automobile. A front vehicle height detection signal and a rear vehicle height detection signal are supplied from these vehicle height sensors 22F and 22R to a control unit 25 serving as a vehicle height adjustment control section. be done.

Each sensor 22F, 22 in the vehicle height sensor 22
R is the Hall IC element and one of the magnets connected to the wheel FA.
and the other side is attached to the vehicle body B side to detect the distance from the normal vehicle height level and the low vehicle height or high vehicle height level, respectively. Note that the vehicle height sensor may be of any other type, for example, one using a phototransistor.

Furthermore, the speedometer 26 has a built-in vehicle speed sensor 27, which detects the vehicle speed and sends a detection signal to the control unit 2.
Mechanical speedometers use a reed switch type vehicle speed sensor, and electronic speedometers use a transistor-based open collector output type sensor.

Further, an acceleration sensor 28 is provided as a vehicle body posture sensor that detects changes in the posture of the vehicle body.
This acceleration sensor 28 is designed to detect changes in the pitch, roll, and yaw of the vehicle on its springs. For example, when there is no acceleration, the weight is in a hanging state and is blocked by a shielding plate from the light emitting diode. The structure is such that the absence of acceleration can be detected by blocking the light from reaching the photodiode.

When acceleration acts in the front and back, left and right, or up and down directions, the weight tilts or moves, and the acceleration state of the vehicle body is detected.

Also, 29 is an indicator that displays the oil pressure.
The display of this indicator 29 is controlled by the control unit 25. A steering sensor 30 detects the rotational speed of the steering wheel 31, that is, the steering speed, and its detection signal is sent to the control unit 25. moreover,
Reference numeral 32 denotes an accelerator opening sensor (not shown) for detecting the depression angle of an accelerator pedal of the engine, and its detection signal is sent to the control unit 25. Further, 33 is a compressor relay for driving the compressor 11, and this compressor relay 33 is controlled by a control signal from the control unit 25. Furthermore, 34 is a pressure switch that is turned on when the pressure in the reserve tank 14 falls below a predetermined value, and its output signal is output to the control unit 25. In other words,
When the pressure in the reserve tank 14 falls below the set value, the pressure switch 34 is turned on, and the compressor relay 33 is activated under the control of the control unit 25.
is activated. As a result, the compressor 11 is driven to feed compressed air into the reserve tank 14, and the pressure inside the reserve tank 14 is made to exceed the set value.

The opening and closing of the air supply solenoid valve 16, the exhaust solenoid valve 20, and the three-way valves 181 to 184 are controlled by control signals from the control unit 25.

Here, FIG. 2 shows two states of the two-position switching type three-way valves 181 to 184 shown in FIG. 1. The second position shown in FIG. 2A is the three-way valve 181.
184 is shown in a driven state, and in this state compressed air moves along the path indicated by arrow A. On the other hand, the first position shown in FIG. 2B is the three-way valve 181.
〜184 is not driven,
In this state, compressed air moves along the path indicated by arrow B.

Next, the operation of an embodiment of the present invention configured as described above will be described. First, the vehicle height adjustment function will be explained. Control unit 25
The outputs of the vehicle height sensors 22F and 22R are read every 6 mS. Then, the outputs of the vehicle height sensors 22F and 22R every 6 mS are added ²⁸ times, and the integrated values are averaged to determine the average vehicle height for 1.5 seconds (hereinafter referred to as
1.5sec average value) is calculated. In other words, 6
(mS) × 2 ⁸ = 1536 (mS) ≒ 1.5 (sec). Then, it is determined to which region (neutral, high, low) the current vehicle height belongs. This kind of judgment is 1.5 seconds above.
It is determined to which region the vehicle height N times the average value belongs. For example, if the vehicle height continues to be high or low for 6 seconds when the vehicle is stopped and for 30 seconds when the vehicle is running, the vehicle height control described later is performed. The vehicle height control described above is carried out by the control unit 25.
The outputs of the vehicle height sensors 22F and 22R, which are read every 6 mS, are stopped when they indicate neutrality.

Next, a specific example of the vehicle height control described above will be explained. For example, when the vehicle is running, if the average vehicle height every 30 seconds is lower than neutral, the air intake solenoid valve 16 is opened by a control signal from the control unit 25. Here, the three-way valve 181
.about.184 are not driven, resulting in the state shown in FIG. 2B. Therefore, the compressed air supplied from the reserve tank 14 is supplied to the air supply solenoid valve 16, the check valve 17, and the three-way valve 181 or 182.
The air is sent to the air spring chambers 3 of the suspension units FS1 and FS2 through the air. At the same time, the compressed air is fed into the air spring chambers 3 of the suspension units RS1, RS2 via the air supply solenoid valve 16, the check valve 19, and the three-way valve 183 or 184. This raises the vehicle height at the front and rear of the vehicle. Then, as described above, the air supply solenoid valve 16 is closed by a control signal from the control unit 25 when the outputs of the vehicle height sensors 22F and 22R every 6 mS indicate neutrality. This stops vehicle height control.

On the other hand, if the average vehicle height every 30 seconds is higher than the neutral, the control unit 25 drives the exhaust solenoid valve 20 and the three-way valves 181-184. As a result, the exhaust solenoid valve 20
opens, and the three-way valves 181-184 change to the state shown in FIG. 2A. Therefore, a part of the compressed air in the air spring chambers 3 of the suspension units FS1, FS2, RS1, RS2 is supplied to the three-way valves 181 to 18.
4, dryer 12, exhaust solenoid valve 20,
It is released to the atmosphere via the check valve 21 and the air cleaner 15. This lowers the height of the front and rear parts of the vehicle body. As mentioned above, when the outputs of the vehicle height sensors 22F and 22R every 6 mS indicate neutral, the exhaust solenoid valve 2
0 and three-way valves 181-184 are turned off. As a result, vehicle height control is stopped.

Next, attitude control when the steering wheel is steered to the right or left will be explained. First, when you turn the steering wheel to the right, the car body tries to roll to the left.
Therefore, the control unit 25 turns on the air supply solenoid valve 16 and the exhaust solenoid valve 20 for a predetermined period of time, and also turns on the three-way valves 182 and 184 on the right side. As a result, compressed air is introduced into the right suspension units FS2 and RS2, and the left suspension units are
Compressed air is released to the atmosphere from FS1 and S1.
This prevents the vehicle from rolling to the left. After a predetermined time, the air supply solenoid valve 16 and the exhaust solenoid valve 20 are turned off, but the three-way valves 182 and 184 remain on, so the left and right air spring chambers 3 are cut off from communicating with each other. Thus, the differential pressure between the left and right air spring chambers 3 is maintained. When the handle returns to neutral, the three-way valve 18 is activated under the control of the control unit 25.
2,184 are turned off. Here, when the three-way valves 182 and 184 are turned off, the left and right air spring chambers 3 are communicated with each other and return to substantially the same pressure as before.

On the other hand, if you turn the steering wheel to the left, the vehicle will roll to the right. For this reason, the control unit 25
As a result, the air supply solenoid valve 16 and the exhaust solenoid valve 20 are turned on for a predetermined period of time, and the left three-way valves 181 and 183 are turned on. This allows the left suspension unit FS1, RS
Compressed air is introduced into the suspension units FS2 and RS2 on the right side, and is released to the atmosphere from the right suspension units FS2 and RS2. This prevents the vehicle body from rolling to the right. The following is the same as when steering the steering wheel to the right.

Next, we will discuss the case of preventing nose dive, where the height of the front part of the vehicle body is lowered when the brake is stepped on. When you step on the brake, the control unit 25 activates the air intake solenoid valve 16, exhaust solenoid valve 20, rear wheel three-way valve 183,
184 is opened for a predetermined time (about 0.2 seconds). As a result, the front suspension unit FS1,
Compressed air is introduced into FS2, and is discharged to the atmosphere from rear wheel suspension units RS1 and RS2. Then, after a predetermined period of time has elapsed, the air intake solenoid valve 16 and the exhaust solenoid valve 20 are turned off, and this state is maintained to keep the vehicle body horizontal. When the deceleration decreases due to the vehicle stopping, for example, the vehicle will stop for a predetermined period of time (approximately 0.2 seconds).
The air supply solenoid valve 16, the exhaust solenoid valve 20, and the three-way valves 181 and 182 are turned on,
Air spring chamber 3 in the front and rear suspension units
The internal pressure is almost returned to the value before the control.

Next, we will discuss the control that prevents the height of the front part of the vehicle body from increasing and the height of the rear part of the vehicle body from decreasing when the vehicle starts. In this case, control unit 2
5, the air supply solenoid valve 16, the exhaust solenoid valve 20, and the front wheel three-way valves 181, 182.
is opened for a predetermined time (about 0.2 seconds). As a result, the rear wheel suspension units RS1 and RS2
Compressed air is introduced into the front wheels, and the compressed air is discharged to the atmosphere from the front wheel suspension units FS1 and FS2. This keeps the vehicle level when starting. When the acceleration decreases due to the vehicle moving to a constant speed, etc., the air supply solenoid valve 16 and the exhaust solenoid valve 20 are
Then, the three-way valves 183 and 184 are turned on, and the internal pressures of the air spring chambers in the front and rear suspension units are returned to approximately the value before the control.

Note that each suspension unit S may be combined with a damping force switching type shock absorber or a damping force spring constant switching type shock absorber to increase the damping force and spring constant of the shock absorber during attitude control.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to provide a vehicle suspension device that can perform vehicle height adjustment and various attitude controls with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a vehicle suspension device according to the present invention, and FIGS. 2A and 2B are diagrams showing on/off states of a three-way valve. 16...Air supply solenoid valve, 181-18
4... Three-way valve, 20... Exhaust solenoid valve, 25... Control unit.

Claims (1)

[Claims] 1 A fluid spring chamber provided for each wheel, a fluid supply means for supplying fluid from a fluid supply source to each fluid spring chamber via a supply on-off valve, and a fluid supply means for supplying fluid from a fluid supply source to each fluid spring chamber via a discharge on-off valve. a three-way valve for the left front wheel, a three-way valve for the right front wheel, and a three-way valve for the left rear wheel, which are interposed between each of the fluid spring chambers and the discharge opening/closing valve, respectively. a three-way valve for the left rear wheel, a front wheel side communication passage whose one end is connected to the three-way valve for the left front wheel and the other end to the three-way valve for the right front wheel, and one end is connected to the three-way valve for the left rear wheel. The directional valve is provided with a rear wheel side communication passage whose other end is connected to the three-way valve for the right rear wheel, and the fluid supply means is arranged such that the fluid that has passed through the supply on-off valve is supplied to the front wheel side fluid spring. The fluid spring chamber is configured to be supplied to the fluid spring chamber through the front wheel side communication passage, and the fluid spring chamber on the rear wheel side is supplied through the rear wheel side communication passage. Consisting of a two-position switching valve that can take a first position that communicates the fluid spring chamber with each of the communication passages, and a second position that allows communication between each of the fluid spring chambers and the discharge on-off valve. Further, a check valve is provided between the supply on-off valve and the front wheel side communication passage and the rear wheel side communication passage to allow fluid to flow only from the supply on-off valve to the respective communication passages. A vehicle suspension device characterized in that each suspension device is provided with a suspension device.