JPH01103507A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To prevent any faulty condition in roll control by informing a fact that an acceleration sensor gets out of order when body acceleration of more than the setting value is continuously detected for more than first specified time, or the body roll control is performed in succession for more than second specified time. CONSTITUTION:A control unit 36 performs charging or exhausting to or from suspension units FS1, FS2, RS1, RS2 is all directions on the basis of longitudinal acceleration of a car body to be detected by an acceleration sensor 39, and also performs roll control. Here, when body acceleration of more than such acceleration that is impossible at the preset normal turning is detected after continuing more than first specified time, or the body roll control is performed in succession of more than second specified time that is impossible at the normal control, the control unit 36 detects it as something trouble in the acceleration sensor 39, thereby informing it with an alarm 47. Any non-conformity in the roll control is thus preventable.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention supplies and exhausts compressed air to and from an air spring chamber provided in each suspension unit of a vehicle body, thereby improving the posture of the vehicle body. The present invention relates to a vehicle suspension device that controls a vehicle suspension system.

(Prior technology) A suspension unit having an air spring chamber is provided for each wheel, and when turning, air is supplied to the air spring chamber of the suspension unit on the compression side, and air is set from the air spring chamber of the suspension unit on the rebound side. A suspension device for a vehicle has been considered that reduces the roll of the vehicle body that occurs when turning by discharging the amount of fluid.

In such a vehicle suspension device, for example, lateral acceleration (lateral G
) is detected by an acceleration sensor, and according to the amount of vehicle body roll obtained based on this lateral G, compressed air from a high-pressure reserve tank is supplied to the air spring of the suspension unit on the compression side, and air in the suspension unit on the rebound side is supplied. Reroll is prevented by discharging air from the spring chamber into a low-pressure reserve tank.

(Problem to be solved by the invention) Therefore, if an abnormality occurs in the acceleration sensor and a lateral G value of the vehicle body that is different from the actual one is detected, the amount of roll control may be too little or too little, or unnecessary roll control may be performed. There is a risk that problems may occur with the vehicle body posture. Therefore, in a suspension device that performs vehicle body roll control as described above, it is necessary to constantly monitor the operating state of its acceleration sensor.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a suspension device for a vehicle that can immediately detect the occurrence of an abnormality in an acceleration sensor and can prevent roll control failures.

[Structure of the Invention] (Means and Effects for Solving the Problems) That is, the vehicle suspension device according to the present invention has a first predetermined vehicle acceleration that is higher than an acceleration that is not possible in normal turning, which is preset by an acceleration sensor. If the acceleration sensor is detected continuously for more than an hour, or if the vehicle body roll control based on the vehicle body acceleration detected by the acceleration sensor is performed continuously for more than a second predetermined time, which is impossible with normal roll control, the acceleration sensor The system is configured to notify of abnormalities.

(Example) An example of the present invention will be described below with reference to the drawings.

In Fig. 1, FSl is a suspension unit on the left front wheel side, FS2 is a suspension unit on the right front wheel side,
R81 is a suspension unit for the left rear wheel, and R82 is a suspension unit for the right rear wheel. Each of these suspension units FS1. FS2. R81, R32
Since the suspension units have the same J14 construction, the suspension units will be described using the reference numeral S, unless the front wheel and rear wheel or the left wheel and right wheel suspension units are explained separately.

The suspension unit S includes a shock absorber 1. This shock absorber 1 includes a cylinder attached to a wheel side, and a piston rod 2 having a piston slidably fitted in the cylinder and having an upper end supported on the vehicle body side. In addition, the suspension unit S is mounted on the upper part of this stain absorber 1.
An air spring chamber 3 having a vehicle height adjustment function is provided coaxially with the piston rod 2. This air spring chamber 3 is partially formed by a bellows 4, and by supplying and discharging air to and from this air spring chamber 3 through a passage 2a provided in the piston rod 2, the vehicle height can be increased or It can be lowered.

Further, a control rod 5 is disposed inside the piston rod 2 and has a valve 5a at its lower end for adjusting the damping force. The control rod 5 is the piston rod 2
It is rotated by an actuator 6 attached to the upper end of the valve 5a to drive the valve 5a.

By rotating the valve 5a, the damping force of the suspension unit is set to three levels: hard, medium, and soft.

The compressor 11 compresses atmospheric air taken in from the air cleaner 12 and supplies it to the high pressure reserve tank 15a via the dryer 13 and check valve 14. In other words,
Since the compressor 11 compresses the atmospheric air taken in from the air cleaner 12 and supplies it to the dryer 13, compressed air dried by silica gel or the like in the dryer 13 is stored in the high-pressure reserve tank 15a. The return pump 16 has its suction port connected to the low pressure reserve tank 15b, and its discharge port connected to the high pressure reserve tank 15a. Reference numeral 18 denotes a low pressure switch that is turned on when the pressure in the low pressure reserve tank 15b exceeds a first set value (for example, 0.6 kg/aI). and,
The return pump 16 is driven by a return pump relay 17 that is turned on by a signal from a control unit 36, which will be described later, when the low pressure switch 18 outputs an on signal. Further, when the low pressure switch 18 outputs an off signal, the return pump 716 is stopped by the return pump relay 17, which is turned off by a signal from the control unit 36.

As a result, the pressure within the low pressure reserve tank 15b is always maintained below the first set value.

Air is supplied from the high-pressure reserve tank 15a to each suspension unit S as shown by solid arrows in FIG. That is, the high pressure reserve tank 15a
The compressed air inside is supplied to the air supply flow rate control valve 19, the front air supply solenoid valve 20, the check valve 21, the front left solenoid valve 22. Suspension unit FS1°F via front right solenoid valve 23
It is sent to S2. Similarly, high pressure reserve tank 1
The compressed air in 5a is supplied to the suspension units R81 and R82 via the air intake flow control valve 19, the rear air intake solenoid valve 24, the check valve 25, the rear left circle solenoid valve 26, and the rear Furukawa solenoid valve 27.
will be sent to

On the other hand, exhaust from each suspension unit S is performed as shown by the broken line arrows in FIG. That is, the compressed air in the suspension units FS1 and FS2 is fed into the low pressure reserve tank 15b via the solenoid valve 22.23 and the exhaust direction switching valve 28 consisting of a three-way valve; , exhaust direction switching valve 28, check valve 29, dryer 1
3. The air may be discharged to the atmosphere via the exhaust solenoid valve 31, check valve 46, and air cleaner 12. Similarly, suspension units R81, R82
The compressed air in
and solenoid valves 26.27,
It may be discharged to the atmosphere via the exhaust direction switching valve 32, check valve 33, dryer 13, exhaust solenoid valve 31, check valve 46, and air cleaner 12. Note that a passage is provided between the check valve 29.33 and the dryer 13, which has a smaller diameter than the passage that directly communicates the exhaust direction switching valve 28.32 and the low pressure reserve tank 15b.

In addition, the above-mentioned solenoid valve 22.23°26.2
7.28 and 32, as shown in Figures 2 (A) and (B), flow air as shown by arrow A when ON (energized state) and flow as arrow B when OFF (de-energized state). Each allows air circulation. In addition, the air supply solenoid valve 20.2
4 and exhaust solenoid valve 31 as shown in Fig. 3(A) and (
As shown in B), when ON (energized state), air circulation is allowed as shown by arrow C, and when OFF (non-energized state), air circulation is prohibited. In addition, the air supply flow rate control valve 19 is turned ON.
In the state (energized), air flows through the orifice O as shown in Figure 4 (A>), so the air flow rate is small and the O
In the FF state (non-energized), air flows through the orifice O and the large path as shown in FIG. 4(B), so the air flow rate increases.

34F is the lower arm 3 of the front right suspension of the vehicle.
5 and the vehicle body to detect the front vehicle height, and 34R is a rear vehicle height sensor installed between the lateral rod 37 of the rear left suspension of the vehicle and the vehicle body to detect the rear vehicle height. It is a sensor. Signals detected by both vehicle height sensors 34F and 34R are supplied to a control unit 36 including a microcomputer.

38 is a vehicle speed sensor built into the speedometer, and supplies a detected vehicle speed signal to the control unit 36. 39 is an acceleration sensor that detects acceleration acting on the vehicle body, and supplies the detected acceleration signal to the control unit 36.

30 is a roll control mode selection switch that selects the roll control mode from SOFT, AUTO, and SPORTS, and 40 is a steering sensor that detects the rotational speed of the steering wheel 41, that is, the steering angular velocity.

42 is an accelerator opening sensor that detects the depression angle of an accelerator pedal of the engine (not shown).

These roll control selection switches 30. Sensors 40 and 4
The detected signal of No. 2 is supplied to the control unit 36. 43 is a compressor relay for driving the compressor 11, and this compressor relay 43 is controlled by a control signal from the control unit 36. 44 indicates that the pressure inside the high pressure reserve tank 15a is the second
This is a high-pressure switch that turns on when the pressure falls below a set value (for example, 9.5 Kg/ri), and a signal from this high-pressure switch 44 is supplied to the control unit 36.

The compressor 11 is driven by a compressor relay 43 that is turned on by a signal from the control unit 36 when the pressure in the high-pressure reserve tank 15a falls below the second set value and the high-pressure switch 44 outputs an on signal. be done. And again, when the high pressure switch 44 outputs an off signal, the compressor 11
The compressor relay 43 is turned off by a signal from the control unit 36, and the compressor is stopped.

As a result, the pressure within the high-pressure reserve tank 15'a is always maintained at or above the second set value. In this case, even if the high pressure switch 44 is on, the compressor 11 is prohibited from being driven when the low pressure switch 18 is on, that is, when the return pump 16 is being driven.

A pressure sensor 45 is provided in a passage that communicates the solenoid pulps 26 and 27 with each other, and detects the internal pressure of the rear suspension units R81 and R82. Also,
An alarm 47 is connected to the control unit 36, and the alarm 47 sounds when an abnormality occurs in the acceleration sensor 39.

In addition, each solenoid valve 19.20.22.2 mentioned above
3.24.26.27.28.31 and 32 are controlled by the I11 control signal q from the control unit 36.

Next, the operation of the suspension device according to the embodiment configured as described above will be explained.

This suspension device has a posture control function and a vehicle height adjustment function. First, the attitude control function that suppresses attitude changes occurring in the vehicle body will be explained.

When the steering wheel 41 is steered to the right, the vehicle body tends to roll to the left. In response, the control unit 36 turns on the air supply solenoid valve 20.24 for a set time according to the leftward acceleration detected by the acceleration sensor 39, and also turns on the solenoid valve 23.2 for the right wheel.
7 is turned on, and after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, a set amount of compressed air is supplied from the high-pressure reserve tank 15a to each air spring chamber 3 of the left suspension units FS1, R8I, and the right suspension units FS2. R8
A set amount of compressed air is discharged from each air spring chamber 3 of No. 2 to the low pressure reserve tank 15b. This suppresses the displacement of the vehicle body from rolling to the left. In this state, a set amount of compressed air is supplied to each air spring chamber 3 of the left suspension unit FS2, R82, and at the same time, a set amount of compressed air is supplied to each air spring chamber 3 of the right suspension unit FS1, R81.
The state in which a set amount of compressed air is discharged from is maintained continuously. Then, when the turning operation shifts to straight-line operation and the control unit 36 detects that the steering becomes neutral by the steering sensor 40 or that the lateral acceleration decreases by the acceleration sensor 39, the control unit 36 activates the solenoid The valves 23 and 27 are turned off, and the exhaust direction switching valve 32 is also turned off. As a result, the air springs 3 of the left and right suspension units are maintained at the same pressure as before the start of control.

On the other hand, when the steering wheel 41 is steered to the left, the vehicle body tends to roll to the right. In response, the control unit 36 turns on the air supply solenoid pulp 20.24 for a set time corresponding to the rightward acceleration detected by the acceleration sensor 39, turns on the left wheel solenoid valve 22.26, and then turns on the left wheel solenoid valve 22.26 for the set time. After the elapse of time, the exhaust direction switching valve 32 is turned on. As a result, the right suspension unit FS2. A set amount of compressed air is supplied from the high pressure reserve tank 15a to each air spring chamber 3 of R32, and the left suspension unit FS1
, R8I from each air spring chamber 3 to the low pressure reserve tank 15.
A set amount of compressed air is discharged at b. This suppresses the displacement of the vehicle body from rolling to the left. Thereafter, the control is performed in the same manner as when the steering wheel 41 is turned to the right as described above.

Next, a description will be given of attitude control in the case of suppressing a nose dive in which the front part of the vehicle body sinks due to negative acceleration acting on the vehicle body when the brake is activated.

When the acceleration sensor 39 detects that negative acceleration in the longitudinal direction of the vehicle exceeds a set value, such as when the brakes are applied, the control unit 36 turns on the air intake solenoid valve 20 for a set time, and turns on the rear wheel. The solenoid valves 26 and 27 are turned on, and after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, the front wheel suspension unit FS1,
A set amount of compressed air is supplied from the high pressure reserve tank 15a of the FS2, and a set m amount of compressed air is discharged from the rear wheel suspension units R31 and R82 to the low pressure reserve tank 15b. In this way, the nose dive is suppressed. This state continues until the angular acceleration weakens.

Then, when the acceleration sensor 39 detects that the angular acceleration has weakened, the control unit 36 turns on the air intake solenoid valve 22.23 for a set period of time, and turns on the rear wheel solenoid valve 26.2.
Turn off 7. As a result, the compressed air is discharged from the front suspension units FS1 and FS2 to the low pressure reserve tank 15b, and the high pressure reserve tank 1 is discharged to the rear suspension units R81 and R82.
A set amount of compressed air is supplied from 5a. In this way, each air spring chamber 3 of each suspension unit S is returned to the state before the start of control.

Next, a description will be given of attitude control in the case of suppressing sifting, in which the front part of the vehicle body rises and the rear part of the vehicle body sinks due to acceleration acting on the vehicle body when the vehicle starts and accelerates. When the accelerator opening sensor 43 or the acceleration sensor 39 detects that the vehicle is rapidly accelerating, the control unit 36 turns on the air intake solenoid valve 24 for a set time and turns on the front wheel solenoid valves 22, 23.
is turned on, and after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, the front wheel suspension unit FS1. A set amount of compressed air is discharged from FS2 to the low pressure reserve tank 15b, and a set amount of compressed air is supplied to the rear wheel suspension units R81 and R82 from the high pressure reserve tank 15a. In this way, the above-mentioned scattering is suppressed. This state continues until the acceleration weakens. Then, the control unit 36 controls the accelerator opening sensor 42.
Alternatively, when the acceleration sensor 39 or the like detects that the sudden acceleration has weakened, the control unit 36
turns on the air intake solenoid valve 20 and the rear wheel solenoid valves 26, 27 for a set time, and turns off the front wheel solenoid valves 22, 23. As a result, a set amount of compressed air is supplied from the high pressure reserve tank 15a to the front wheel suspension units FSI and FS2, and the rear wheel suspension units R81 and R8
A set amount of compressed air is discharged from 2 to the low pressure reserve tank 15b. In this way, each air spring chamber 3 of each suspension unit S is returned to the state before the start of control.

Next, the abnormality detection operation of the acceleration sensor 39 accompanying the above attitude control will be explained.

Figure 5 shows the output characteristics of the acceleration sensor 39, from leftward acceleration 0.75G-OG to rightward acceleration 0.75G.
*t- is output as a voltage signal of ov~2.5V~5V.

FIG. 6 is a flowchart showing the abnormality detection processing operation of the acceleration sensor accompanying the above-mentioned attitude control. That is, with the above-mentioned roll control processing, the acceleration detection signal G supplied from the acceleration sensor 39 is ro, 5V≦G≦ 4.5Vl, that is, 0.6G or less in both the left and right directions, and if it is determined that roll control is not in progress, the roll control timer TCs error timer T built in the control unit 36
E Rs and the G sensor abnormality flag GF are reset (steps 81 to 87). In this case, the acceleration sensor 39
This means that no abnormality has occurred.

On the other hand, in step S2 or S3, the acceleration detection signal G supplied from the acceleration sensor 39 is rG>4.5.
When it is determined that VJ or rG<4.5VJ, that is, the acceleration in the right or left direction exceeds the normally unthinkable high acceleration of 0.6G, the error timer VER built into the control unit 36 starts counting operation. It is determined whether the count data exceeds 1.01 inch (
Step 88.89). In this step S9, "
YES", that is, when it is determined that the abnormal output state of the acceleration sensor 39 has continued for a first predetermined time (1ain) or more, the control unit 36 sets the G sensor flag GF and drives the alarm 47 to sound (step S10).
．． 511).

On the other hand, in step S4, rYEsJ, that is,
When it is determined that the roll control operation is in progress and the lateral acceleration G detected by the acceleration sensor 39 is 0.6 G or less in both the left and right directions, the roll control timer Tc built in the control 0-Schnitt 36 starts counting operation. , it is determined whether the count data exceeds a second predetermined time (3i+in) (step 312.813). This step 8
13, rYEsJ, that is, the roll control state based on the lateral acceleration detection signal from the acceleration sensor 39 is normal roll! III! If it is determined that the second predetermined time (3ain) or more continues, which is impossible with 1, the control unit 36 sets the G sensor flag GF as described above and drives the alarm 47 to sound (step S10).
．． 511).

As a result, the acceleration sensor 39 continuously outputs a high acceleration detection signal that is normally not possible for a long time (first predetermined time), or O-ru II based on the lateral acceleration detected by the acceleration sensor 39 If an abnormality (short circuit, wire breakage, etc.) in the acceleration sensor 39 is detected due to continuous control for an unusually long time (second predetermined time), an alarm 47 alerts the driver to the abnormal state. be informed.

Therefore, according to the suspension device having the above configuration,
Compressed air is supplied to the air spring chamber 3 of the compression side suspension unit S according to the amount of roll of the vehicle body based on the lateral acceleration detected by the acceleration sensor 39, and compressed air is supplied from the air spring v3 of the compression side suspension unit S. Not only can anti-roll 2iII Ill be performed by exhausting the air, but also an abnormal state of the acceleration sensor 39 can be detected and notified to the driver. Therefore, the driver can immediately request a service to repair the abnormal part of the acceleration sensor 39, and can prevent problems from occurring in the roll control process.

[Effects of the Invention] As described above, according to the present invention, when a vehicle body acceleration that is higher than an acceleration that is not possible in a preset normal turning is continuously detected by an acceleration sensor for a first predetermined R or more, or when the above-mentioned acceleration The vehicle body roll control based on the body acceleration detected by the sensor is performed at a second predetermined time I, which is not possible with normal roll control.
I! Since the structure is configured so that an abnormality in the acceleration sensor is notified if the above is performed continuously, it is possible to immediately know the occurrence of an abnormality in the acceleration sensor and prevent roll control failure. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram (not showing the structure) of a vehicle suspension system according to an embodiment of the present invention, and FIGS. 2(A) and (B) are respectively the drive and non-operation diagrams of a three-way valve provided in the vehicle suspension system. Diagram showing the driving state, Figure 3 (A> and (B)
FIG.
A) and (B) are diagrams showing the driving and non-driving states of the air supply flow rate control pulp in the vehicle suspension device, respectively, FIG. 5 is a diagram showing the output characteristics of the acceleration sensor in the vehicle suspension device, and FIG. 6 is a diagram showing the output characteristics of the acceleration sensor in the vehicle suspension device. The figure is a flowchart showing the abnormality detection processing operation of the acceleration sensor in the vehicle suspension system. FSl, FS2, R31, R82... Suspension unit, 3... Air spring to, 4... Bellows, 1
DESCRIPTION OF SYMBOLS 1...Compressor, 15a...High pressure reserve tank, 15b...Low pressure reserve tank, 16...Return pump, 17...Return pump relay, 18.
...Low pressure switch, 36...Control unit, 38...Vehicle speed sensor, 39...Acceleration sensor,
40...Steering sensor, 43...Compressor relay, 44...High pressure switch, Tc...Roll control timer, TER...Error timer, GF...G sensor abnormality flag. Applicant's agent Patent attorney Takehiko Suzue (A) CB) Figure 2 (A) (B) Figure 3 Figure 4

Claims (1)

[Claims] A roll control function that supplies fluid to the fluid spring chamber of the suspension unit on the compression side and discharges fluid from the fluid spring chamber of the suspension unit on the extension side according to the amount of vehicle body roll based on the vehicle body acceleration detected by the acceleration sensor. In the vehicle suspension system having the above-mentioned vehicle suspension system, the above-described vehicle body roll control is performed when a vehicle body acceleration equal to or higher than a preset acceleration is continuously detected by the acceleration sensor for a first predetermined period of time or more, or based on the vehicle body acceleration detected by the acceleration sensor. 1. A suspension device for a vehicle, comprising: a sensor abnormality notification means for notifying an abnormality of the acceleration sensor when the acceleration sensor is continuously performed for a second predetermined time period or more.