JPH0635244B2 - Vehicle suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a vehicle suspension device, and in particular to supplying air to an air spring chamber of a suspension on the extension side with respect to a direction of a posture change of a vehicle, The present invention relates to a vehicle suspension device configured to suppress a change in posture of a vehicle by discharging air from an air spring chamber of a suspension on the contraction side.

(Prior Art) A suspension unit having an air spring chamber is provided for each wheel, and air is supplied to the air spring chamber of the suspension unit on the contraction side (outer side of the turn) at the time of turning, and the suspension unit on the extension side (inner side of the turn) is supplied. A vehicle suspension device having an attitude control function has been considered, which reduces the roll of the vehicle body generated during turning by discharging air from the air spring chamber.

Further, in a suspension device as disclosed in, for example, Japanese Patent Laid-Open No. 61-263815, in addition to a high pressure side reserve tank for supplying air to the air spring chamber, a low pressure side reserve into which air discharged from the air spring chamber is introduced. In addition to providing a tank, a reserve tank that absorbs air from the low-pressure side reserve tank and projects to the high-pressure side reserve tank is provided, and the air pressure system is a closed loop to minimize the intrusion of water contained in the outside air. Things are known. It should be noted that in this device, for example, when the load capacity is large, a large amount of air is required for the pneumatic system, so a compressor for introducing outside air into the pneumatic system is provided. The return pump and the compressor are controlled so that the return pump is driven when the internal pressure of the low-pressure side reserve tank reaches the set high pressure state, and the compressor is driven when the internal pressure of the high-pressure side reserve tank reaches the set low pressure state.

(Problems to be Solved by the Invention) In this conventional suspension device, since the return pump and the compressor use the battery mounted in the vehicle as a power source, the power generation capacity of the generator is low when the vehicle is stopped. Therefore, it is preferable that these return pump and compressor are not driven as much as possible.

However, for example, if the vehicle height is adjusted to increase the vehicle height that the occupant gets in while the vehicle is stopped, the internal pressure of the high-pressure side reserve tank will naturally decrease, but in this case, the pneumatic system Since the required absolute air amount also increases, it is necessary to secure the drive of the compressor. Therefore, it is conceivable that the drive of the return pump is prohibited when the low-pressure side reserve tank becomes the set high-pressure state for some reason while the vehicle is stopped, in which a dynamic posture change of the vehicle does not substantially occur. When the high pressure side reserve tank is in the set low pressure state, the compressor is driven to raise the high pressure side reserve tank to the required pressure. Therefore, when the vehicle travels from this state, the return pump is driven and the high-pressure side reserve tank becomes abnormally high.

The present invention was devised in view of the above, and by not driving the return pump as much as possible while the vehicle is stopped,
An object of the present invention is to provide a vehicle suspension device that can reduce power consumption while the vehicle is stopped.

[Configuration of the Invention] (Means and Actions for Solving Problems) Air spring chambers provided between wheels and a vehicle body, provided for each wheel, and supply valve means for each air spring chamber High-pressure side reserve tank connected to each air spring chamber, low-pressure side reserve tank connected to each air spring chamber via discharge valve means, detection means for detecting a factor of posture change occurring in the vehicle, and the detection means When the cause of the attitude change that occurs is detected, compressed air is supplied to the compression side air spring chamber and compressed air is discharged from the expansion side air spring chamber with respect to the direction of the attitude change. Attitude control means for controlling the valve means, a return pump that absorbs the air in the low pressure side reserve tank and discharges it to the high pressure side reserve tank, and a return pump that absorbs outside air and discharges it to the high pressure side reserve tank. Compressor, a high pressure side pressure sensor that detects the internal pressure of the high pressure side reserve tank, a low pressure side pressure sensor that detects the internal pressure of the low pressure side reserve tank, and a detection value of the high pressure side pressure sensor and the low pressure side pressure sensor. A drive control means for controlling the drive of the return pump and the compressor, and a vehicle speed detection means for detecting a vehicle speed, wherein the drive control means has a drive signal for the compressor, and the low pressure side reserve sensor causes the low pressure side reserve sensor to detect the vehicle speed. It is output when the internal pressure of the tank is not set to the set high pressure state and when the internal pressure of the high pressure side reserve tank is detected to be the set low pressure state by the high pressure side pressure sensor. When the drive signal is detected by the vehicle speed sensor to be equal to or higher than the set vehicle speed, the low pressure side pressure sensor is used. Is output when it is detected that the internal pressure of the low pressure side reserve tank has reached a set high pressure state, and when the vehicle speed detection means detects that the vehicle speed is less than the set vehicle speed, the low pressure side pressure sensor Output only when the internal pressure of the low pressure side reserve tank is detected to be in the set high pressure state and the high pressure side pressure sensor detects that the high pressure side reserve tank is not in the set low pressure state. It is a vehicle suspension device characterized by being configured.

According to the present invention, by setting the set vehicle speed as low as possible, when the power generation capacity of the generator provided in the vehicle is small, including when the vehicle is stopped, the return pump is set even if the low pressure side reserve tank becomes the set high pressure state. When the low pressure side reserve tank is in the set high pressure state and the high pressure side reserve tank is in the set low pressure state, the drive signal of the return pump is output.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, FS1 is a left front wheel side suspension unit, FS2 is a right front wheel side suspension unit, RS1 is a left rear wheel side suspension unit, RS
2 is a suspension unit on the right rear wheel side. Each of these suspension units FS1, FS2, RS1, R
Since S2 has the same structure as each other, the suspension unit will be described by using the reference symbol S, except for the case of distinguishing between the front wheels and the rear wheels or the left wheels and the right wheels.

The suspension unit S includes a shock absorber 1. The shock absorber 1 includes a cylinder mounted on the 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 attached to the upper part of the shock absorber 1.
An air spring chamber 3 having a function of adjusting the vehicle height is provided coaxially with the piston rod 2. A part of the air spring chamber 3 is formed by a bellows 4, and air is supplied to and discharged from the air spring chamber 3 through a passage 2a provided in the piston rod 2 to raise or lower the vehicle height. Can be lowered.

Further, inside the piston rod 2, a control rod 5 having a valve 5a for adjusting the damping force at the lower end is arranged. The control rod 5 is a piston rod 2
The valve 6 is driven by being rotated by an actuator 6 attached to the upper end of the valve. By the rotation of the valve 5a, the damping force of the suspension unit is set to three levels of hard (hard), medium (medium), and soft (soft).

The compressor 11 compresses the air taken in from the air cleaner 12 and sends it to the high pressure reserve tank 15 a via the dryer 13 and the check valve 14. That is,
Since the compressor 11 compresses the air taken in from the air cleaner 12 and supplies it to the dryer 13, the compressed air dried by silica gel or the like in the dryer 13 is stored in the high-pressure reserve tank 15a. The suction port of the compressor 16 is connected to the low pressure reserve tank 15b, and the discharge port thereof is connected to the high pressure reserve tank 15a. Reference numeral 18 denotes a pressure switch which is turned on when the pressure in the low pressure reserve tank 15b becomes equal to or higher than a first set value (for example, atmospheric pressure). When the compressor 16 outputs an ON signal of the pressure switch 18, the compressor 16 is driven by a compressor relay 17 which is turned on by a signal from a control unit 36 described later. As a result, the pressure in the low pressure reserve tank 15b is always kept below the first set value.

The air is supplied from the high pressure reserve tank 15a to each suspension unit S as shown by the solid line arrow in FIG. That is, the compressed air in the high pressure reserve tank 15a is supplied to the suspension units FS1 and FS via 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, and the front right solenoid valve 23.
Delivered to 2. Similarly, the high pressure reserve tank 15
The compressed air in a is sent to the suspension units RS1 and RS2 via the air supply flow rate control valve 19, the rear air supply solenoid valve 24, the check valve 25, the rear left solenoid valve 26, and the rear right solenoid valve 27. To be done.

On the other hand, the exhaust from each suspension unit S is performed as shown by the broken line arrow in FIG. That is, the compressed air in the suspension units FS1 and FS2 is supplied to the low pressure reserve tank 15b via the exhaust direction switching valve 28 including the solenoid valves 22 and 23 and the three-way valve, and the solenoid valves 22 and 23. , Exhaust direction switching valve 28, check valve 29, dryer 1
3, it may be discharged to the atmosphere via the exhaust solenoid valve 31, the check valve 46 and the air cleaner 12. Similarly, the suspension units RS1 and RS2
Compressed air in the low pressure reserve tank 15b passes through the solenoid valves 26 and 27 and the exhaust direction switching valve 32.
When it is fed into the solenoid valve 26, 27,
It may be discharged to the atmosphere via the exhaust direction switching valve 32, the check valve 33, the dryer 13, the exhaust solenoid valve 31, the check valve 46 and the air cleaner 12. A passage having a smaller diameter than the passage that directly connects the exhaust direction switching valves 28 and 32 and the low pressure reserve tank 15b is provided between the check valves 29 and 33 and the dryer 13.

The above-mentioned solenoid valves 22, 23, 26, 2
As shown in FIGS. 2 (A) and 2 (B), reference numerals 7, 28 and 32 denote air flow as indicated by an arrow A when ON (energized state) and air as indicated by an arrow B when OFF (non-energized). To allow the distribution of each. The air supply solenoid valves 20 and 24 and the exhaust solenoid valve 31 are shown in FIGS. 3 (A) and 3 (B).
As shown in FIG. 3, when ON (energized state), air circulation is permitted as indicated by arrow C, and when OFF (non-energized state) air circulation is prohibited. Further, when the supply air flow control valve 19 is in the off state (non-energized), the orifice o as shown in FIG.
The air flow rate is small because it circulates through the air passage, and the air flow rate is large in the ON state (energized state) because the air circulates through the orifice o and the large path D as shown in FIG. 4 (B). .

34F is the lower arm 3 of the right front suspension of the vehicle.
5 is a front vehicle height sensor that is mounted between the vehicle body and the vehicle body to detect the front vehicle height; and 34R is a rear vehicle height that is mounted 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. The signals detected by the vehicle height sensors 34F and 34R are supplied to a control unit 36 equipped with a microcomputer.

A vehicle speed sensor 38 is incorporated in the speedometer and supplies the detected vehicle speed signal to the control unit 36. Reference numeral 39 denotes an acceleration sensor that detects the acceleration acting on the vehicle body, and supplies the detected acceleration signal to the control unit 36. Reference numeral 30 is a roll control mode selection switch for selecting the roll control mode from soft (SOFT), auto (AUTO), and sport (SPORTS), and 40 is a steering sensor for detecting the rotation speed of the steering wheel 41, that is, the steering angular speed. Reference numeral 42 is an accelerator opening sensor for detecting the depression angle of the accelerator pedal of the engine (not shown). The signals detected by the roll control selection switch 30, the sensors 40 and 42 are supplied to the control unit 36. Reference numeral 43 is a compressor relay for driving the compressor 11, and the compressor relay 43 is controlled by a control signal from the control unit 36. 44 is a high pressure reserve tank 15a
This is a pressure switch that is turned on when the internal pressure falls below a ^second set value (for example, 7 kg / cm ² ), and the signal of this pressure switch 44 is supplied to the control unit 36.
Then, when the pressure in the high-pressure reserve tank 15a becomes equal to or lower than the set value and the pressure switch 44 is turned on, the control unit 36 turns on the pressure switch 18, that is, when the compressor 16 is driven, It is configured to prohibit driving. Reference numeral 45 is a pressure sensor provided in a passage that connects the solenoid valves 26 and 27 to each other, and detects the internal pressure of the rear suspension units RS1 and RS2.

The solenoid valves 19, 20, 22, 2 described above
Control of 3, 24, 26, 27, 28, 31 and 32 is performed by a control signal from the control unit 36.

Next, the operation of the apparatus according to the embodiment configured as described above will be described. This device has an attitude control function and a vehicle height adjustment function. First, the attitude control function of suppressing the attitude change occurring in the vehicle body will be described.

When the steering wheel 41 is steered to the right, the vehicle body tries to roll to the left. On the other hand, the control unit 36 turns on the air supply solenoid valves 20 and 24 for a set time, and also controls the solenoid valves 23 and 27 of the right wheel.
Is turned on, and after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, the set amount of compressed air is supplied from the high-pressure reserve tank 15a to the air spring chambers 3 of the left suspension units FS1 and RS1, and the right suspension units FS2 and RS2 are supplied.
The set amount of compressed air is discharged from each of the air spring chambers 3 to the low pressure reserve tank 15b. This suppresses the displacement of the vehicle body that attempts to roll to the left. In this state, that is, the set amount of compressed air is supplied to the air spring chambers 3 of the left suspension units FS2 and RS2, and the set amount of compressed air is discharged from the air spring chambers 3 of the right suspension units FS1 and RS1. The state is maintained continuously. Then, when the control unit 36 detects that the steering sensor 40 makes the steering neutral or the acceleration sensor 39 reduces the lateral acceleration, the control unit 36 causes the solenoid valve to move. 23 and 27 are turned off, and the exhaust direction switching valve 32 is turned off. As a result, the air spring chambers of the left and right suspension units are kept at the same pressure as before the control was started.

On the other hand, when the steering wheel 41 is steered to the left, the vehicle body tries to roll to the right. On the other hand, the control unit 36 turns on the air supply solenoid valves 20 and 24 for the set time, and at the same time, the left solenoid valve 2
2, 26 are turned on, and after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, each air spring chamber 3 of the right suspension unit FS2, RS2
The compressed air is supplied from the high pressure reserve tank 15a to a set amount, and the left suspension unit FS1,
Low pressure reserve tank 15b from each air spring chamber 3 of RS1
The set amount of compressed air is discharged to. As a result, the displacement of the vehicle body attempting to roll to the left is suppressed. Hereinafter, control is performed in the same manner as when the steering wheel 41 is steered to the right.

Next, a description will be given of attitude control in the case where a negative acceleration acts on the vehicle body when the brake is actuated to suppress the nose dive in which the front portion of the vehicle body sinks. When the acceleration sensor 39 detects that the negative acceleration in the front-rear direction of the vehicle body is equal to or greater than the set value, for example, when the brake is operated, the control unit 36 turns on the air supply solenoid valve 20 for the set time, and also controls 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 set amount of compressed air is supplied from the high pressure reserve tanks 15a of the front wheel suspension units FS1 and FS2, and the set amount of compressed air is discharged from the rear wheel suspension units RS1 and RS2 to the low pressure reserve tank 15b. In this way, the nose dive is suppressed. This state continues until the negative acceleration is weakened. Then, when the acceleration sensor 39 detects that the negative acceleration is weakened thereafter, the control unit 3
6 turns on the air supply solenoid valves 22 and 23 for a set time and turns off the rear-wheel solenoid valves 26 and 27. As a result, a set amount of compressed air is discharged from the front wheel suspension units FS1 and FS2 to the low pressure reserve tank 15b, and the high pressure reserve tank 15a is discharged to the rear wheel suspension units RS1 and RS2.
A set amount of compressed air is supplied from. In this way, each air spring chamber of each suspension unit S is returned to the state before the start of control.

Next, the attitude control in the case of suppressing the squat in which the front portion of the vehicle body lifts and the rear portion of the vehicle body sinks due to the acceleration acting on the vehicle body when the vehicle starts to accelerate will be described. When the accelerator opening sensor 43, the acceleration sensor 39, or the like detects that the vehicle is in rapid acceleration, the control unit 36 turns on the air supply solenoid valve 24 for a set time and turns on the solenoid valves 22 and 23 of the front wheels. Further, after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, the set amount of compressed air is discharged from the front wheel suspension units FS1 and FS2 to the low pressure reserve tank 15b, and the set amount of compressed air is supplied to the rear wheel suspension units RS1 and RS2 from the high pressure reserve tank 15a. . In this way, the squat is suppressed. This state is continued until the acceleration is weakened. Then, after that, the control unit 36 controls the accelerator opening sensor 42.
Alternatively, when the acceleration sensor 39 or the like detects that the rapid acceleration is weakened, the control unit 36
Turns on the air supply solenoid valve 20 and the rear-wheel solenoid valves 26 and 27 for a set time, and turns off the front-wheel solenoid valves 22 and 23. As a result, the set amount of compressed air is supplied from the high pressure reserve tank 15a to the suspension units FS1 and FS2 for the front wheels, and the suspension units RS1 and R for the rear wheels are provided.
The set amount of compressed air is discharged from S2 to the low pressure reserve tank 15b. In this way, each air spring chamber of each suspension unit S is returned to the state before the start of control.

Meanwhile, while the roll control as described above is being executed, the drive of the return pump 16 and the compressor 11 is controlled according to the determinations of the high pressure side pressure switch 44 and the low pressure side pressure switch 18. First, it is determined whether the pressure switch 18 is on, that is, is equal to or larger than the first set value (step S1). By the determination in this step S1,
If the determination is "NO", the return pump 16 is stopped (step S2). Then, it is determined whether the pressure switch 44 on the high pressure side is on, that is, is equal to or less than the second set value (step S3). If the determination in step S3 is "NO", the compressor 11 is stopped and "Y
If it is determined to be "ES", the compressor 11 is driven.

By the way, when it is determined to be "YES" in the above step S1, it is determined whether the high pressure side pressure switch 44 is on (step S6). If it is on, the compressor 16 is stopped (step S7). When it is not turned on, it is determined whether the vehicle speed is 3 km / h or more (step S8), and when it is determined as "YES", that is, when the vehicle is traveling, the return pump 16 is It is driven (step S9). That is, the sixth
As shown in the figure, when the drive condition of the compressor 11 is also satisfied, but the drive condition of the return pump 16 is also satisfied, the return pump 16 is driven only while the vehicle is traveling. That is, when the vehicle is stopped, the return pump 16 is not driven and the power consumption is reduced.

EFFECTS OF THE INVENTION According to the present invention, by setting the set vehicle speed as low as possible, the low-pressure side reserve tank is set to the set high-pressure state when the power generation capacity of the generator provided in the vehicle is small, including when the vehicle is stopped. However, the drive signal of the return pump is not output, but when the low pressure side reserve tank is in the set high pressure state and the high pressure side reserve tank is in the set low pressure state, the return pump drive signal is output.

Therefore, without causing any of the problems described above,
While the vehicle is stopped, it is possible to reduce the chances of driving the return pump as much as possible, and thus it is possible to provide a vehicle suspension device that can reduce power consumption while the vehicle is stopped.

[Brief description of drawings]

FIG. 1 is a diagram showing a vehicle suspension device according to an embodiment of the present invention, FIG. 2 is a diagram showing a three-way valve driven / non-driven state, and FIG. 3 is a solenoid valve driven / non-driving state. FIG. 4 is a diagram showing the drive and non-drive states of the supply air flow rate control valve, FIG. 5 is a flow chart showing the operation of one embodiment of the present invention, and FIG. 6 is a high pressure reserve tank and a low pressure reserve tank. It is a figure which shows the relationship of a pressure change, a compressor drive signal, and a return pump drive signal. 15a ... high pressure reserve tank, 15b ... low pressure reserve tank, 19 ... supply air flow control valve, 22, 23,
26, 27 ... Solenoid valve, 36 ... Control unit, 45 ... Pressure sensor.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shozo Takizawa 5-3-8 Shiba, Minato-ku, Tokyo Within Mitsubishi Motors Corporation (72) Inventor Minoru Tadamoto 5-33-8 Shiba, Minato-ku, Tokyo No. Mitsubishi Motors Co., Ltd. (56) References JP-A-58-156454 (JP, A) Actually developed 61-43510 (JP, U)

Claims (1)

[Claims] 1. An air spring chamber provided between a wheel and a vehicle body and provided for each wheel, a high pressure side reserve tank connected to each air spring chamber via a supply valve means, and each air spring. The low-pressure reserve tank connected to the chamber through the discharge valve means, the detection means for detecting the cause of the attitude change occurring in the vehicle, and the attitude change when the cause of the attitude change occurring in the vehicle is detected by the detecting means. The attitude control means for controlling the supply valve means and the discharge valve means so that the compressed air is supplied to the compression side air spring chamber and the compressed air is discharged from the expansion side air spring chamber, and the low pressure side. A return pump that absorbs air from the reserve tank and discharges it to the high-pressure side reserve tank, a compressor that absorbs outside air and discharges it to the high-pressure side reserve tank, and a high-pressure side reserve tank And the high-pressure side pressure sensor for detecting a,
A low pressure side pressure sensor that detects the internal pressure of the low pressure side reserve tank, drive control means that controls the drive of the return pump and the compressor according to the detection values of the high pressure side pressure sensor and the low pressure side pressure sensor, and the vehicle speed is detected. The drive control means detects that the internal pressure of the low pressure side reserve tank is not in the set high pressure state by the low pressure side pressure sensor, and the high pressure control means Output when the side pressure sensor detects that the internal pressure of the high pressure side reserve tank has reached the set low pressure state, and the drive signal of the return pump is detected by the vehicle speed sensor to be equal to or higher than the set vehicle speed. Is that the low pressure side pressure sensor detects that the internal pressure of the low pressure side reserve tank has reached a set high pressure state. When it is detected that the vehicle speed detection means is less than the set vehicle speed, the low pressure side pressure sensor detects that the internal pressure of the low pressure side reserve tank is in the set high pressure state and A vehicle suspension device configured to output only when the high pressure side pressure sensor detects that the high pressure side reserve tank is not in the set low pressure state.