JPH01103508A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To control power consumption by stopping the operation of a return pump, which compresses air in a low pressure side reserve tank and feeds it into a high pressure side reserve tank, when car stoppage is detected by a signal out of a car speed sensor. CONSTITUTION:A control unit 36 feeds compressed air in a high pressure side reserve tank 15a to suspension units FS1, FR1 at the contracted side of to a fluid spring chamber 3 of suspension units FS2, FR2, and it is exhausted to a low pressure side reserve tank 15b from the expansion side, thereby performing roll control. Here, when a high pressure switch 44 detects a pressure drop in the high pressure side reserve tank 15a, a compressor 11 is driven to feed the air thereinto, and when a fact that pressure in the low pressure side reserve tank 15b becomes more than the specified value is detected by a low pressure switch 18, a return pump 16 is driven for feeding it to the high pressure side, but if car stoppage is detected by a car speed sensor 38, the return pump 16 is no longer operated. Power consumption is thus cut down.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Application Field) The present invention provides a suspension for a vehicle that reduces power consumption by not driving a return pump when the vehicle is stopped. Regarding equipment.

(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.

(Problems to be Solved by the Invention) In such a suspension system for a vehicle, a fluid spring chamber is provided for each suspension unit that supports each wheel, and compressed air from the high pressure side reserve tank is transferred to the compression side. Supply air to the suspension 22t spring chamber,
Rolling is prevented by discharging air from the air spring chamber of the suspension unit on the rebound side to the low-pressure side reserve tank. When such roll control is performed, the pressure in the high-pressure side reserve tank decreases and the pressure in the low-pressure side reserve tank increases. Therefore, compressed air is supplied to the high-pressure side reserve tank by compressing the atmosphere with a compressor, and the low-pressure side reserve tank is By compressing the air in the reserve tank via a return pump and supplying the compressed air to the high-pressure reserve tank, the pressure in the low-pressure reserve tank is reduced. In a vehicle suspension device configured as described above, there is a problem in that operating the return pump when the vehicle is stopped is undesirable in terms of power consumption.

The present invention has been made in view of the above points, and an object of the present invention is to provide a vehicle suspension device that suppresses power consumption by not driving the return pump when the vehicle is stopped. .

[Structure of the invention] (Means and effects for solving the problem) A fluid spring chamber is provided for each suspension knee unit that supports each wheel, and compressed air from the high-pressure side reserve tank is transferred to the suspension unit on the compression side. In a vehicle suspension system that prevents the occurrence of roll by supplying air to the air spring chamber and discharging air from the air spring chamber of the suspension unit on the rebound side to the low-pressure side reserve, the internal pressure of the high-pressure side reserve tank is a high-pressure switch that detects the internal pressure of the low-pressure side reserve tank, a low-pressure switch that detects the internal pressure of the low-pressure side reserve tank, a compressor that compresses and sends outside air to the high-pressure side reserve tank, and a compressor that compresses the air in the low-pressure side reserve tank. The power consumption is reduced by using a return pump that feeds the high-pressure side, a vehicle speed sensor that detects the vehicle speed, and the return pump that does not operate when the vehicle is stopped.

(Example) An example of the present invention will be described below with reference to the drawings. In Figure 1, FSI is the suspension unit for the left front wheel, FS2 is the suspension unit for the right front wheel, R81 is the suspension unit for the left rear wheel, and R82 is the suspension unit for the left front wheel.
is the suspension unit for the right rear wheel. Each of these suspension units FS1. FS2. RSl, RS
Since the suspension units 2 have similar structures, the suspension units will be described using the reference numeral S, unless the suspension units for the front wheels and those for the rear wheels or for the left wheels and those for the right wheels are explained separately.

The suspension unit S includes a shock absorber 1. This shock absorber 1 includes a cylinder attached to 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. Further, the suspension unit S includes an air spring chamber 3 coaxially with the piston rod 2 above the shock absorber 1 and having a vehicle height adjustment function. This air spring chamber 3 is partially formed by a bellows 4, and the air spring chamber 3 is
By supplying and discharging air to and from the vehicle, the vehicle height can be raised or 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, the compressed air dried by silica gel or the like in the dryer 13 is stored in the high pressure reserve tank 15a. The compressor 16 has a suction port connected to a low pressure reserve tank 15b and a discharge port connected to a high pressure reserve tank 15a. Reference numeral 18 denotes a pressure switch that is turned on when the pressure in the low pressure reserve tank 15b exceeds a first set value (for example, atmospheric pressure). And compressor 16
When the pressure switch 18 outputs an on signal, the compressor relay 17 is driven by the compressor relay 17, which is turned on by a signal from a control unit 36, which will be described later. 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 compressed air in the high pressure reserve tank 15a 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 FSI via front useful solenoid valve 23.

Sent to FS2. Similarly, the compressed air in the high-pressure reserve tank 15a is supplied through one air supply flow rate control valve, a rear air intake solenoid valve 24, a check valve 25, a rear left circular solenoid valve 26, and a rear solenoid valve 27. Suspension unit R3I, R3
2.

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 13
, exhaust solenoid valve 31, check valve 46, and air cleaner 12, and may be exhausted to the atmosphere. Similarly, the compressed air in the suspension units R3I and RS2 is supplied into the low pressure reserve tank 15b via the solenoid valve 26.27 and the exhaust direction switching valve 32, and in the other case, the compressed air is fed into the low pressure reserve tank 15b via the solenoid valve 26.27 and the exhaust direction switching valve 32. Valve 32, check valve 33, dryer 13, exhaust solenoid valve 31, check valve 4
6 and air cleaner 12, and may be discharged to the atmosphere. 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 air as shown by arrow B when OFF (de-energized). The distribution of each is permitted. In addition, the air supply solenoid valve 20.24 and the exhaust solenoid valve 31 are shown in Fig. 3 (A) and (B).
As shown in the figure, 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, when the air supply flow rate control valve 19 is in the OFF state (not energized), the orifice is 0 as shown in FIG. 4(A).
Since the air flows through the valve, the air flow rate is small; in the on state (energized), the air flows through the orifice 0 and the large path, as shown in Figure 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 sport (5 PORTS); 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). Signals detected by the roll control selection switch 30 and the sensors 40 and 42 are 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. 4
Reference numeral 4 denotes a pressure switch that is turned on when the pressure in the high-pressure reserve tank 15a falls below a second set value (for example, 7 degrees/cm 2 ), and a signal from this pressure switch 44 is supplied to the control unit 36 . The control unit 36 controls the compressor 11 when the pressure in the high pressure reserve tank 15a is below the set value and the pressure switch 18 is on even if the pressure switch 44 is on, that is, when the compressor 16 is being driven. It is configured to prohibit driving.

A pressure sensor 45 is provided in a passage that communicates the solenoid valves 26 and 27 with each other, and detects the internal pressure of the rear suspension units RSI and R82.

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

Next, the operation of the apparatus according to the embodiment configured as described above will be explained. This device has an attitude 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 period of time, and also turns on the right wheel solenoid valve 23.27.
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 FSI, RSI, and the right suspension units FS2. R82
A set amount of compressed air is discharged from each air spring chamber 3 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 the right suspension unit FS1
, R81, the state in which a set amount of compressed air is discharged from each air spring chamber 3 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 valve. 23 and 27 are turned off, and the exhaust direction switching valve 32 is also turned off.

As a result, the air spring chambers 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 valve 20.24 for a set period of time, and also turns on the left wheel solenoid valve 22.
．． 26 is turned on, and after the set time has elapsed, 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, R
A set amount of compressed air is discharged from each air spring chamber 3 of the SI to the low pressure reserve tank 15b.

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 2o for a set period of 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 FSI,
A set amount of compressed air is supplied from the high pressure reserve tank 15a of the FS2, and a set amount of compressed air is discharged from the rear wheel suspension units R3I and R92 to the low pressure reserve tank 15b. In this way, the nose dive is suppressed. This state continues until the negative acceleration weakens.

Then, when the acceleration sensor 39 detects that the negative 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, a set amount of compressed air is discharged from the front wheel suspension units FSI, FS2 to the low pressure reserve tank 15b, and at the same time, the compressed air is discharged from the high pressure reserve tank 1 to the rear wheel suspension units RSI, R82.
A set amount of compressed air is supplied from 5a. In this way, each air spring chamber 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 a drift, 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 period of time, turns on the front wheel solenoid valves 22 and 23, Further, after the set time has elapsed, the exhaust direction switching valve 32 is turned on. As a result, the front wheel suspension units FSI, F
A set amount of compressed air is supplied from S2 to the low pressure reserve tank 15b.
At the same time, a set amount of compressed air is supplied from the high-pressure reserve tank 15a to the rear wheel suspension units R3I and R32. In this way, the above-mentioned scattering is suppressed. This state continues until the acceleration weakens. Then, the control unit 36
When the accelerator opening sensor 42 or the acceleration sensor 39 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 and 27 for a set period of time. At the same time, the front wheel solenoid valve 22
．． 23 is turned off. As a result, the high pressure reserve tank 15a is transferred to the front suspension units FSI and FS2.
A set amount of compressed air is supplied from the rear wheel suspension units R81 and RS2, and a set amount of compressed air is discharged from the rear wheel suspension units R81 and RS2 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.

By the way, 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, the pressure is equal to or higher than a first set value (step Sl). In this step S1 determination,
If the determination is "No", the return pump 16 is stopped (step S2). Then, it is determined that the pressure switch 44 on the high pressure side is on, that is, the pressure is equal to or less than the second set value (step S3). If the determination in step s3 is rNOJ, the compressor 11 is stopped and rY
If it is determined that the condition is EsJ, the compressor 11 is driven.

By the way, if it is determined as rYESJ in the above step S1, it is determined whether the pressure switch 44 on the high pressure side is on (step S6). If it is on, the compressor 16 is stopped (step S7). If it is not turned on, it is determined whether the vehicle speed is 3 km/h or more (step S8), and if it is determined that the vehicle is running, the return pump 16 is turned on. In other words, as shown in FIG. 6, if the drive conditions for the compressor 11 are also satisfied, but the drive conditions for the return pump 16 are also satisfied, the drive is performed only while the vehicle is running. Then, the return pump 16 is driven.

In other words, when the vehicle is stopped, return pump 1
6 is not driven, reducing power consumption.

[Effects of the Invention] As detailed above, according to the present invention, the drive of the return pump is stopped when the vehicle is stopped, which reduces power consumption when the vehicle is stopped and prevents the battery from running out. It can be prevented.

[Brief explanation of the drawing]

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 in a driven state and a non-driven state, and FIG. 3 is a diagram showing a solenoid valve in a driven and non-driven state. FIG. 4 is a diagram showing the driving and non-driving states of the supply air flow rate control valve, FIG. 5 is a flowchart showing the operation of an embodiment of the present invention, and FIG. 6 is a diagram showing the operation of the high pressure reserve tank and the low pressure reserve tank. FIG. 3 is a diagram showing the relationship between pressure changes, compressor drive signals, and return pump drive signals. 15a...High pressure reserve tank, 15b...Low pressure reserve tank, 19...Air supply flow rate control valve, 22゜23.26.27...Solenoid valve, 36...
Control unit, 45...pressure sensor. Applicant's representative Patent attorney Takehiko Suzue (A) CB) Figure 2 (A) CB) Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] A fluid spring chamber is provided for each suspension unit that supports each wheel, and compressed air from the high-pressure side reserve tank is supplied to the air spring chamber of the suspension unit on the compression side, and compressed air is supplied from the air spring chamber of the suspension unit on the compression side. In a vehicle suspension system that prevents rolling by discharging air into a low-pressure side reserve tank, a high-pressure pressure switch detects the internal pressure of the high-pressure side reserve tank and detects the internal pressure of the low-pressure side reserve tank. a compressor that compresses and sends outside air to the high-pressure side reserve tank; a return pump that compresses air in the low-pressure side reserve tank and sends it to the high-pressure side; a vehicle speed sensor that detects vehicle speed; A suspension device for a vehicle, characterized in that the return pump does not operate when the vehicle is stopped.