JPH068892Y2 - Vehicle suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement of a vehicle suspension device.

(Prior art) A suspension unit having an air spring chamber for each angle theory is provided, and air is supplied to the air spring chamber of the suspension unit on the contraction side during turning, and the air is set from the air spring chamber of the suspension unit on the extension side. A vehicle suspension device has been considered in which the roll of the vehicle body generated at the time of turning is reduced by discharging only the above.

(Problems to be solved by the invention) However, in such a vehicle suspension device, the roll control amount is determined according to the steering wheel angular velocity or the lateral acceleration, but when the steering wheel angular velocity is used, the flow rate control is performed. The valve is used to switch the fluid supply amount so that the fluid supply amount is increased and the roll control is performed quickly. When the lateral acceleration G is applied, the flow control valve is used to reduce the fluid supply amount and the roll control is performed slowly. However, if the roll control based on the steering wheel angular velocity is performed and then the control according to the acceleration G in the left-right direction is performed, the roll control is suddenly performed and then the control is slowly performed, which is uncomfortable.

The present invention has been made in view of the above points, and an object thereof is a vehicle for which a feeling of discomfort can be eliminated even when control according to the lateral acceleration G is performed after roll control by the steering wheel angular velocity is performed. To provide a suspension device.

[Construction of the Invention] (Means and Actions for Solving Problems) Fluid spring chambers provided for each suspension unit supporting each theory, and a fluid is provided to each fluid spring chamber via a supply valve means. Fluid supply means for supplying the fluid, a flow rate control valve provided in the flow path for supplying the fluid and capable of varying the flow rate per unit time, and a fluid for discharging the fluid from each of the fluid spring chambers via the discharge valve means. The discharging means, the steering wheel angular velocity detecting means for detecting the steering wheel angular velocity, the acceleration detecting means for detecting the lateral acceleration acting on the vehicle body, and the angular velocity detected by the steering wheel angular velocity detecting means when the setting conditions are satisfied. 1st according to the angular velocity
First control target setting means for setting the roll control target, and when the acceleration detected by the acceleration detection means satisfies the setting condition, the second roll control target is set according to the acceleration at that time. 2 control target setting means,
Fluid is supplied to the fluid spring chamber of the suspension unit on the contraction side and fluid of the suspension unit on the extension side in accordance with the larger roll control target set by the first and second control target setting means. The above-mentioned supply valve means and discharge valve means are driven so as to discharge the fluid from the spring chamber, and the roll control executed is first performed according to the first roll control target set by the first control target setting means. If done in
During the roll control to be executed, the flow rate per unit time of the flow rate control valve becomes larger than that in the case where it is first performed according to the second roll control target set by the second control target setting means. And a roll control means for controlling the above.

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 fitted in the cylinder so as to be swingable 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 same pressure switch 18, it 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 fed to the low pressure reserve tank 15b through 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.
And when it is fed into the solenoid valves 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 in which a small-diameter throttle L is inserted is provided between the check valves 29 and 33 and the dryer 13 as compared with a passage which directly connects the exhaust direction switching valves 28 and 32 and the low pressure reserve tank 15b. There is.

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, 24 and the exhaust solenoid valve 31 are shown in FIGS. 3 (A) and 3 (B).
As shown in FIG. 5, when ON (energized state), air circulation as indicated by arrow C is permitted, 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 state), 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 including an input circuit, an output circuit, a memory and 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 (not shown) that detects the depression angle of the accelerator pedal of the engine. 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, the control unit 36 turns on the pressure switch 18 even if the pressure in the high-pressure reserve tank 15a becomes equal to or lower than the second set value and the pressure switch 44 is turned on.
That is, when the compressor 16 is being driven, the driving of the compressor 11 is prohibited. Four
Reference numeral 5 denotes 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 embodiment of the present invention configured as above will be described. FIG. 11 shows the control unit 3
6 is a flowchart schematically showing a series of roll control performed in 6. First, in a rough road determination routine (step A1) as a rough road determination means, so-called rough road determination processing is performed. That is, in this rough road determination routine, when the output change of the front vehicle height sensor 34F is equal to or higher than MHz (N times or more in 2 seconds), the dead zone of the G sensor 39 at this time is widened to determine the rough road, and roll control is performed. Reduced erroneous operation. In the roll control routine (step A2) as the roll control means, roll control is performed, that is, air is supplied to the suspension unit on the contraction side and exhausted from the suspension unit on the expansion side to prevent the roll of the vehicle body during turning. ing. Further, the air supply / exhaust time during the roll control is corrected in the air supply / exhaust correction routine (step A3) as the air supply / exhaust time correction means, and the air supply / exhaust time of the four wheels is corrected. Further, a damping force switching routine as a damping force switching means (step A
In 4), the damping force of each suspension unit is set to the optimum one of hard (hard), medium (medium), and soft (soft). Less than,
The processing of steps A1 to A4 will be described in detail.

First, the detailed operation of the rough road determination routine (step A1) will be described with reference to FIG. First, the front vehicle height Hf detected by the front vehicle height sensor 34F is read into the control unit 36 every predetermined time (step B1). In the main routine shown in FIG. 11, various flags IT, A, B, UP, D described later are provided.
It is assumed that N is set to "0". The flag IT is set to "1" when the rough road determination is started, and the flag A is set to "1" from the time when the front vehicle height Hf shifts from the decreasing state to the increasing state to the time when the front vehicle height Hf shifts to the decreasing state again. The flag B is set to "1" from the time when the front vehicle height Hf changes from the increasing state to the decreasing state to the time when the front vehicle height Hf changes to the increasing state again, and the flag UP maintains the decreasing tendency of the front vehicle height Hf. The flag DN is set to "1" when the vehicle is running, and the flag DN is set to "1" when the front vehicle height Hf shows an increasing tendency.

First, in the first determination in step B2, the flag I
Since T is "0", it is determined to be "ON", and the flag I
After T is set to "1", the current front vehicle height Hf is stored in the register HA and the timer Tc is reset (steps B3 to B5).

Then, when the front vehicle height Hf is next read by the control unit 36, in step B2, "YE
S ”, and the timer Tc sets the interval time INT
Is incremented only (step B6). And
It is determined whether the current front vehicle height Hf is smaller than the stored vehicle height HA (step B7) or larger than the vehicle height HA (step B22), and the process described later is performed according to the determination. For example, if the front vehicle height signal Hf is input from time t0 as shown in FIG. 14, the front vehicle height Hf tends to increase, and therefore it is determined in step B22 that “HA <Hf”, The process proceeds to step B23. Since the flag UP is set to “0” in the initial setting, “flag DN = 1”,
After "flag B = 0" is set (steps B26, B
27), the current front vehicle height Hf is stored in HA (step B13). Then, it is determined whether or not “A × B = 1”, that is, whether or not “A = B = 1” (step B14).
This determination is “A × B = 1” when the increase / decrease tendency is reversed when the front vehicle height Hf increases / decreases. Since "A = B = 0" at this stage, "O = O" at step B14.
N "is determined. Next, the routine proceeds to step B16, where it is determined whether or not the timer Tc has counted for 2 seconds or more. However, since 2 seconds have not elapsed at this point, the routine proceeds to step B28. In step B28, it is determined whether or not the cross-count determination is set, but since it has not been set yet, the process returns.

Thereafter, at time t1, the front vehicle height Hf starts to decrease, so that "YES" is determined in step B7 and the process proceeds to the determination in step B8. Here, "flag DN
= 1 ”is determined, but the flag DN is set to the above step B2.
Since it is set at 6, it is determined to be "YES" and "flag B = 1" and "flag DN = 0" are determined (steps B9 and B10). After that, the time t described above
As in the case of 0, steps B13, B14, B16, B
Returned via 28. Then, as shown in FIG. 14, the front vehicle height Hf continues to fall between times t1 and t2.
When it is determined to be “S” and the determination in step B8 is reached, the flag DN = 0 is set, so that the flag A = 0 and UP = 1 are set as shown in FIG. 14 (steps B11 and 12). ).

Then, after time t2 in FIG. 14, the front vehicle height H
When f starts to rise, it is determined to be "YES" in step B22 and the process proceeds to the determination in step B23. However, since the flag UP has already been set here, the flag A = 1.
And flag UP = 0 (steps B24, B
25).

In this way, as shown in FIG. 14, the front vehicle height H
When f goes up and down, the flag B is set to "1" from the time when the front vehicle height Hf goes from the rising state to the time when the front vehicle height Hf goes to the rising state again, and the front vehicle height Hf goes down. The flag A is set to "1" from the time when the state shifts to the rising state to the time when the state shifts to the falling state again. Then, after passing through step B13, the process proceeds to step B14. At this stage, “A =
Since “1” and “B = 1”, “A × B = 1” is established, and the process proceeds to step B15. As described above, flags A and B
Are both “1” only when the increasing / decreasing tendency of the front vehicle height Hf is reversed, and “A × B = 1” is obtained at each inversion. Therefore, in step B15, the counter NC
NT is incremented by "+1". That is, the counter NCNT is incremented by "+1" by one increase or decrease in the front vehicle height Hf. The above process is repeated until the count of the timer Tc exceeds 2 seconds, but the count of the timer Tc becomes 2
When it exceeds the second, the timer Tc is reset and NC
It is determined whether the count value of NT is N or more (step B
16-B18). That is, when it is detected that the front vehicle height Hf has increased or decreased more than N times within 2 seconds, it is determined that the road is bad, NCNT = 0, the bad road determination is set, and the delay timer TR = 0 is set. (Step B19-2
After 1), it is returned.

By the way, when it is determined to be "NO" in step B16 or B18 and the rough road determination is set, the delay timer TR is incremented by the time INT, and when the delay timer TR becomes larger than 4 seconds, the rough road determination is reset. (Steps B29 to B31). In this way, the rough road determination is reset 4 seconds after the last rough road determination is set, that is, 2 seconds after it is determined in step B18 that the road is not a rough road (“NO”). As described above, in the rough road determination routine A1, in step B15, every time the increase or decrease in the front vehicle height Hf is reversed,
The counter NCNT is incremented by "+1". Then, when the counter NCNT for 2 seconds is N or more, a rough road determination indicating a rough road is set (step B2).
0). Then, this rough road judgment is reset 2 seconds after the judgment of "NO" (that is, it is judged that the road is not a bad road) in the step B18 (step B31).

Next, the detailed operation of the roll control routine (step A2) will be described with reference to the flowchart of FIG. First, the vehicle speed V detected by the vehicle speed sensor 38, the lateral acceleration G output from the G sensor 39 and its differential value, and the steering wheel angular velocity H detected by the steering sensor 40.
Is read by the control unit 36 (steps C1 to C3). And the steering wheel angular velocity H is 30 deg / s
It is determined whether it is larger than ec (step C4). That is,
It is determined whether the steering wheel is steered. Step C4 above
In, if it is determined to be "YES", it is determined whether "GxH" is correct (step C5). That is, it is determined whether the acceleration G in the left-right direction and the steering wheel angular velocity H are in the same direction.
If it is determined to be "negative", it means that the steering wheel is steered to the turning side. If "YES" is determined in the above step C5, one of the VH maps of FIG. 5 to FIG. 7 selected according to the preference of the user is referred to, and the vehicle speed and the steering wheel angular velocity are referred to. The control level TCH corresponding to the
6). In this step C6, when the roll control selection switch 30 selects the soft mode as the roll control mode, the map shown in FIG. 5 is displayed, and when the roll control mode is the automatic mode, the map shown in FIG. When the sports map is selected as the roll control mode, the map of FIG. 7 is selected. Then, the supply / exhaust time and the damping force as shown in FIG. 9 are selected corresponding to the control level TCH of each map. The relationships among the steering wheel angular velocity H, vehicle speed V, control level, mode, supply / exhaust time, and damping force shown in FIGS. 5 to 7 and 9 are stored in the memory in the control unit 36. Then, the air supply / exhaust correction routine, which will be described in detail later with reference to FIG. 16, corrects and calculates the air supply / exhaust times TCS and TCE independent of the front and rear wheels (step C).
7). Next, it is determined whether the control flag is being set (step C8). Since the roll control has not been started yet, it is determined to be "NO" and the process proceeds to step C9. In step C9, it is determined whether the air supply / exhaust flag SEF is set. If the supply / exhaust flag SEF is set in the supply / exhaust correction routine (step C7), the control flag is set and the supply / exhaust timer T = 0 is set (steps C10, C11). Then, the routine proceeds to step C12, where it is judged whether or not the differential pressure is being held, that is, whether or not the differential pressure holding flag described later is set. When there is a differential pressure, the front and rear exhaust direction switching valves 28 and 32 are turned off so that the air discharged from the front or rear is discharged to the low pressure reserve tank 15b. This is because the exhaust direction switching valves 28 and 32 are on while the differential pressure is being held, and therefore it is necessary to turn off these exhaust direction switching valves 28 and 32 in order to perform additional supply / exhaust control. is there. Next, in the air supply / exhaust correction routine in step C7, it is determined whether the air supply coefficient KS = 3 is set (step C14), and if it is not set (that is, KS = 1), the air supply flow rate control valve is set. 19 is turned on, the large path D (Fig. 4) is opened, and the supply air flow rate is increased (step S15). That is, since KS = 1 is the case where the control level TCH is obtained from the vehicle speed-steering wheel angular velocity map as shown in FIG. 16, the air flow rate is increased in order to perform the rapid roll control.

Next, the front and rear air supply valves 20 and 24 are turned on (step C16). And the acceleration G in the left-right direction
The orientation of is determined by the control unit 36 (step C17). That is, it is determined whether the direction of the acceleration G in the left-right direction is positive or negative. Here, when the acceleration G is positive, it is determined that the acceleration G is a right turn in the traveling direction, that is, a left turn. On the other hand, when the acceleration G is negative, it is determined that the acceleration G is a left turn in the traveling direction, that is, a right turn. Therefore, when the acceleration G is determined to be right (left turn), the front and rear left solenoid valves 22 and 26 are turned on (step C18). As a result, the air in each air spring chamber 3 of the left suspension unit is discharged into the low pressure reserve tank 15b via the valves 22 and 26 which are in the ON state, and at the same time, each air spring chamber 3 of the right suspension unit is discharged. Air is supplied to the inside from the high pressure reserve tank 15a via the air supply valves 20 and 24 in the on state and the valves 23 and 27 in the off state.

On the other hand, when it is determined that the acceleration G is on the left side (right turn), the front and rear right solenoid valves 23 and 27 are turned on (step C19). As a result, the air in the air spring chambers 3 of the right suspension unit is discharged into the low pressure reserve tank 15b via the valves 23 and 27 which are in the on state, and the air spring chambers 3 of the left suspension unit are also discharged. To the air supply valves 20 and 24 in the ON state and the valve 22 in the OFF state, respectively.
Air is supplied from the high pressure reserve tank 15 a via 26.

Next, the swing back flag is reset, the differential pressure holding flag described above is set, and the duty timer TD, the duty counter Tn, and the duty time counter Tmn are set to zero (steps C20 to C24). Hereinafter, the process returns to step C1. Then, steps C1 to C7
Then, the process proceeds to step C8. At this time, since the control flag is being set, “YE
It is determined to be "S" and the process proceeds to step C25. Then, in step C25, the timer T is updated by adding the interval time INT. Then, the count value of the timer T is equal to or greater than the air supply time TCS or the count value of the timer T is equal to the exhaust time TCS.
Until CE or more, the roll control for supplying and exhausting the air spring chambers of the left and right suspension units according to the direction of the left and right G is continuously performed. By the way, timer T
When the count value of is greater than or equal to the exhaust time TCS, it is determined to be "YES" in step C26, the flow control valve 19 is turned off, the air supply solenoid valves 20 and 24 are turned off, and the air supply operation is stopped (step C27, C28). As a result, the air spring chamber 3 on the air supply side is maintained in a high pressure state in which air is supplied for the air supply time TCS. When the count value of the timer T becomes equal to or longer than the exhaust time TCE, it is determined to be "YES" in step C29, and the exhaust direction switching valve 28,
32 is turned on, and the exhaust operation is stopped (step C3
0). As a result, the air spring chamber 3 on the exhaust side is kept in a low pressure state in which the air spring chamber 3 is exhausted for the exhaust time TCE. Then, the direction of the acceleration G in the left-right direction is stored in the memory Mg, and when “timer T ≧ TCS”, the control is reset, the roll control is stopped, and the state is held (steps C32, C33). . In this way, the roll generated on the vehicle body during turning is suppressed. The above processing has been described for the case where the steering wheel is steered abruptly.
Even if "H≤30 deg / sec", if "Gx" is positive (step C34), the control level TCG is obtained by referring to the G sensor map of FIG. 8, and the following TCH is obtained. Roll control is performed by performing the same processing as the above. In Fig. 8, V1 is 30km / h, V2 is 130km / h
Is set to. The air supply / exhaust time and damping force corresponding to this control level TCG can be obtained from FIG. also,
The relationship between the left and right G, the vehicle speed V, the control level, the mode, the air supply / exhaust time, and the damping force shown in FIGS. 8 and 10 is stored in the memory in the control unit 36. As is clear from FIGS. 8 and 10, this G
The air supply / exhaust time finally obtained from the sensor map varies depending on the mode selected by the control switch 30. Although there is no description of the soft mode in FIG. 10, this means that the control level is always zero in the G sensor map when the soft mode is selected.

As will be described later in detail with respect to the supply / exhaust time correction routine C7, in the present device, the front wheel-side air supply time and the rear wheel-side supply / exhaust time are set to be different from each other. Therefore, the supply / exhaust time is counted independently on the front wheel side and the rear wheel side based on the count of the supply / exhaust time.

By the way, when "Gx" is negative, that is, when the steering wheel is on the return side, the map of FIG. 6 is referred to and the vehicle speed-steering wheel angular velocity map on the return side is referred to (step C36), and the threshold value is set. HM is obtained, and it is determined whether or not the steering wheel angular velocity on the return side is H ≧ HM (step C3).
7). When it is determined "YES" in step C37, the temporal change of the acceleration G in the left-right direction is 0.6 g / sec.
It is determined whether or not this is the case (step C38). here,
When it is determined to be "YES" in steps C37 and C38, that is, when the turning traveling is changed to the straight traveling, the steering wheel is rapidly returned to its neutral position and the acceleration G is increased.
If there is a large change with time, so-called rolling back, in which the single body passes through its neutral state and rolls to the opposite side, occurs, so the processing in and after step C39 is performed to prevent this.

In step C39, it is determined whether the swing back flag is set. Here, when the process first comes to step S39, the rewind flag is not set, so
It is determined to be "NO", the swing back flag is set, and the swing back timer TY is set to "0" (step C).
40, C41). When it is determined that the acceleration G stored in the memory Mg is left (right turn), the front and rear right solenoid valves 23 and 27 are turned off, and the acceleration G is right (left turn). When the determination is made, the front and rear left solenoid valves 22 and 26 are turned off, and the air spring chambers 3 of the left and right suspension units are communicated with each other (steps C42 to C44). As a result, the timing of communication between the air spring chambers 3 of the left and right suspension units is accelerated, so that the pressure difference between the left and right air spring chambers 3 caused by the roll control is prevented from increasing the rolling back of the vehicle body. To be done. Further, the front and rear air supply valves 20 and 24 are turned off, the exhaust direction switching valves 28 and 32 are turned off, the differential pressure holding flag is reset, the control level CL = 0, and the control flag is also reset. Then, the process returns to step C1 (steps C45 to C49). When it is determined to be "YES" in steps C37 and C38 and the process proceeds to step C39, the rewind flag is already set, so the process proceeds to the rewind routine after step C50.

That is, the count value of the timer TY is incremented, and it is determined whether the count value of the timer TY is 0.25 seconds or more (step C5).
0, C51). In this step C51, "NO"
When it is determined that the process returns to step C1 above,
When the timer TY is stepped through the subsequent processing and the count value of the timer TY becomes 0.25 seconds or more, the count value of the timer TY becomes 2.2 again.
It is determined whether it is 5 seconds or more (step C52). Therefore, when the count value of the timer TY is 0.25 seconds or more and less than 2.25, it is determined as "NO" in the above step C52, and the process proceeds to step 53 and subsequent steps. This step C53
It is determined whether or not the acceleration G in the left-right direction is determined by
When it is determined that the direction of g is right, the front and rear left solenoid valves 22 and 26 are turned on, and when it is determined that the lateral acceleration G is left, the front and rear right solenoid valves 23. , 27 are turned on. Further, the exhaust direction switching valves 28 and 32 are turned on (steps C53 to C56). By the processing in step C54, the spring constants of the front and rear suspension units can be increased. In this way, when the steering wheel angular velocity H is equal to or greater than the threshold value in FIG. 6 and the temporal change in the lateral acceleration G on the return side becomes 0.6 g / sec or more, the left and right air spring chambers 3 are immediately moved to each other. To prevent the differential pressure between the left and right air spring chambers 3 generated by the roll control from increasing the rolling back of the vehicle body. Further, 0.25 seconds after that, the left-right communication is closed for 2 seconds, so that when the vehicle body returns to its neutral state, the spring constant of each air spring chamber 3 increases and the rolling of the vehicle body to the opposite side is reduced. After 2.25 seconds, step C above
In 52, it is determined to be "YES", the swing back flag is reset, and the swing back processing is ended. (Step C57). Thereafter, the processing of the step C42 and thereafter is performed, and thereafter, the processing of the step C1 and thereafter is performed.

By the way, in the step C37 or C38, "N
If it is determined to be “O”, that is, if the steering wheel is slowly returned when shifting from turning to straight traveling, or if the temporal change of the acceleration G is small, the above-described control relating to swinging back is not suitable. The control described below is performed. That is, first, it is determined whether or not the swing back flag is set (step C58), and if it is set, the process proceeds to step C50 and subsequent steps. This may actually be the case in the control process for rollback.

On the other hand, since the swing-back flag is not set when the above-mentioned turning traveling is slowly shifted to straight traveling, it is determined to be "NO" in step C58, and then the acceleration G in the left-right direction is at the dead zone level. That is, "G ≤
G0 "(step C59), and if it is the dead zone level, it is determined whether the differential pressure is being held (step C60). If the differential pressure is being held, step C61.
Proceeding to the subsequent processing, the differential pressure between the left and right air spring chambers 3 is gradually released by duty control.

Hereinafter, the processing of the duty control routine performed after step C61 will be described. First, it is determined whether the duty control count Tn is 3 or more (step C6).
1). Then, it is determined whether the duty timer Td is Tmn or more (step C62). Here, since both TD and Tmn are initially “0”, it is determined to be “YES”. However, if "NO" in step C62, the duty timer Td is incremented (step C6).
3), the processing for making the damping force of the shock absorber 1 one step harder is performed by steps C64 to 67. In addition,
Although not shown, between steps C63 and C64, after the damping force of the shock absorber 1 is set in step C66 or C67 in one control for releasing the differential pressure between the left and right air spring chambers 3, the step C63 is performed. There is a step of returning when the processing is completed.

By the way, if it is determined to be "YES" in the determination in step C62, that is, if the duty timer Td becomes Tmn, the process proceeds to step C68 and subsequent steps, and the process for intermittently communicating the left and right air spring chambers 3 is started. It First, the direction Mg of the acceleration G in the left-right direction stored in step C31 is determined (step C68). If the direction of the acceleration G in the left-right direction is the left side, step C69
Then, it is determined whether or not the front and rear right solenoid valves 23, 27 are turned off. Initially, these valves 23 and 27 are on (that is, in a differential pressure state)
Therefore, it is turned off in step C71. As a result, the left and right air spring chambers 3 are communicated with each other, and the air in the left air spring chamber 3 flows into the right air spring chamber 3. Further, in steps C72 and C73, the duty counter Tn is incremented, and the duty timer Tmn is set to "Tmn + Tm" (Tn is 0.
A constant of about 1 second) is set and the process returns to step C1. Then, after Tm seconds, in step C62, "YE
“S” and C68 are determined as “left” to reach C69. At step C69, since the right solenoid valves 23 and 27 have already been turned off, it is determined to be "YES" and step C
Proceeding to 70, the solenoid valves 23 and 27 are turned on. Next, in Step C73, the duty timer T
“Tmn + Tm” is set in mn. In this way
When the process of opening the solenoid valves 23 and 27 for Tm seconds is performed three times, that is, when the communication between the left and right air spring chambers 3 is performed three times, “YES” is determined in step C61. And steps C74, C75, C76, C82
The front and rear exhaust direction switching valves 28 and 32 are turned off, the differential pressure holding flag is reset, the control level CL is set to 0, and the series duty control is ended.

By the way, if it is determined in step C68 that the position is "right", the same processing as steps C69 to C71 is performed on the left solenoid valves 22 and 26. When this process is also performed three times, the process proceeds to step C74, and the series of processes is ended.

As described above, when the steering wheel is slowly returned when shifting from turning traveling to straight traveling, or when the temporal change of the acceleration G is small, the difference between the left and right air spring chambers 3 is controlled by the series of duty control. Since the pressure is gradually released, the inside of each air spring chamber 3 can be returned extremely smoothly to the state before the control.

Next, the supply / exhaust correction routine of step A3 described above will be described in detail with reference to FIG. First, the internal pressure of the rear suspension units RS1 and RS2 is detected by a signal from the pressure sensor 45 (step D).
2). Next, the control level TCG obtained from the G sensor map of FIG. 8 or the control level TCH obtained from one of the steering wheel angular velocity-vehicle speed maps of FIGS. 5 to 7 is compared with the control level CL ( If a control level TCG or TCH higher than the control level CL is obtained in steps D3 and D4), it is stored in the control level CL (steps D8 and D17). The control level register CL is set to "0" as an initial value.

On the other hand, when it is determined that either the control level TCG or TCH is smaller than the control level CL, the air supply / exhaust flag SEF is reset, the damping force switching position is reset, and the dead zones are set at the control levels TCG and TCH. "1" is set (steps D5 to D7).

By the way, after the control level TCG is set to the control level CL in step D8, if "TCH≤1" (that is, the lateral acceleration acting on the vehicle body is small), the air supply coefficient Ks is "3". Is set (step D1
0). On the other hand, when “TCH> 1” (that is, when the lateral acceleration acting on the vehicle body is small), the air supply coefficient Ks is set to “1” (step D11). In step D17, the control level DL is set to the control level DL.
If is set, "1" is set to the air supply coefficient Ks (step D11).

Then, a supply / exhaust flag SEF indicating that it is necessary to perform supply / exhaust control after step D10 or D11.
Is set (step D12), and air is supplied and exhausted by the roll control routine of FIG. And the twelfth
It is determined whether the rough road determination set by the rough road determination routine in the figure is set (step D13). In this step D13, when it is determined that the rough road determination is set, it is determined whether the control level TCG is "2" (step D14), and when the control level is "2", the feed is determined. The exhaust flag SEF is reset, and the dead zone level "1" is set to the control level TCG (steps D15 and D16). That is, as shown in FIG.
When the control level TCG is "2" at the time of rough road determination, the roll control is performed during the supply / exhaust time of 150 ms in the normal time, but the supply / exhaust time is set to "0" and the roll control is not performed. . In other words, when a rough road is determined, such as when driving on a rough road, the dead zone width of the G sensor is widened to prevent the roll control from malfunctioning on a rough road.

By the way, the above steps D7, D13, D14, D16
After the processing of (1) is completed, referring to FIG. 9 or FIG. 10 from the obtained control level TCH or TCG, the basic time Tc of supply / exhaust according to the control level TCH, TCG
Is required (step D18). Next, the pressure sensor 4
Rear suspension unit RS1, RS by 5
The internal pressure of 2 (rear internal pressure) is detected, and the front internal pressure is estimated from this rear internal pressure by referring to the front internal pressure-rear internal pressure characteristic diagram of FIG. The front internal pressure-rear internal pressure characteristic diagram will be described in more detail as follows. In other words, comparing the case where one passenger is seated in the front seat and two passengers are seated in a typical passenger car with two passengers in the front seat and one passenger is seated in the rear seat, strictly speaking, this characteristic diagram is shown. Don't However, it has been confirmed by experiments that the approximate value of the actual front internal pressure can be obtained from the rear internal pressure by creating a characteristic diagram that approximates each riding pattern in consideration of all riding patterns. Further, in the characteristic diagram of FIG. 17, three characteristics of high vehicle height, normal vehicle height and low vehicle height are shown. These are high vehicle height, normal vehicle height and low vehicle height, respectively, and the rear internal pressure is Is different from the front internal pressure. As a matter of course, this characteristic diagram is used that is suitable for the vehicle height at that time. From the front internal pressure estimated in this way and the rear internal pressure obtained from the pressure sensor 45,
The air supply / exhaust correction coefficient characteristic diagram in the figure is referred to determine the front / rear air supply correction coefficient PS and the front / rear air supply correction coefficient PE (step D19). In FIG. 18, when the internal pressure of the suspension is high, the air supply time is required to supply the same amount of air longer than when the internal pressure is low. Therefore, the correction coefficient PS is set to the internal pressure Po. It is proportional, and when the internal pressure of the suspension is high, the exhaust time is shorter than when the internal pressure is low, because the time required to exhaust the same amount of air is shorter.
The correction coefficient PE is inversely proportional to the internal pressure PO.

Next, it is determined whether or not the compressor 16 (return pump) is stopped (step D20), and when it is stopped, that is, when the pressure difference between the high pressure reserve tank 15a and the low pressure reserve tank 15b is large, the suspension Since the air supply / exhaust has a large air flow rate even for a short time, the initial coefficient FK is set to 0.8 (step D21). On the other hand, when it is not stopped, that is, when the pressure difference between the high pressure reserve tank 15a and the low pressure reserve tank 15b is small, the initial coefficient FK is set to 1 and the supply / exhaust time is not corrected (step D22).

Next, the already calculated basic time Tc of air supply is multiplied by the air supply correction coefficient PS, the air supply coefficient KS, and the initial coefficient FK to obtain the corrected air supply time TCS (step D
23). Also, the basic time T of the exhaust gas that has already been required
The corrected exhaust time TCE is obtained by multiplying c by the exhaust correction coefficient PE and the initial coefficient FK (step D2).
4). The air supply time TCS and the exhaust time TCE are
Since the front wheel side and the rear wheel side have different correction coefficients, they are individually calculated.

Next, referring to FIGS. 9 and 10, the control level TC
A damping force switching position corresponding to G and TCH is obtained, and that position is set as the damping force target value DST (step D2).
5). Next, when the rough road determination is set, if the damping force target value DST is hard, it is changed to medium (steps D26 to D28: these steps correspond to damping force control means). This improves the ability of the wheels to follow the road surface when traveling on a rough road.

Next, the damping force switching routine (step A4) will be described with reference to FIGS. 19 and 20. First, based on the control level TCH or TCG, FIG.
It is determined whether the damping force target value DST obtained from the figure is larger than the manually set damping force value MDST (step E1). If it is larger, the damping force current value DDST is made equal to the damping force target value DST. The damping force is switched and the timer TDS is reset (steps E2 to E4). The damping force value MDST is set to "SOFT" in the SOFT mode and the AUTO mode and "HARO" in the SPORT mode. When the damping force present value DDST becomes equal to the damping force target value DST, the timer TDS is counted until the timer TDS counts 2 seconds (steps E5 and E6). And timer T
When the DS has counted 2 seconds, the timer TDS is reset (step E7). And if the differential pressure is being held,
The damping force value MDST set manually is restored (step E9).

On the other hand, if it is determined in step E8 that the differential pressure is being held, that is, if the roll control is being held, the process of reducing the damping force by one step is performed in the following steps E10 to E12. In other words, if the damping force current value DDST is hard, the damping force is set to medium and the damping force current value DD is
If ST is not hard, the damping force is softened. Although not shown between steps E8 and E10,
After the damping force is changed in step E11 or E12 during a series of holding the differential pressure, steps E10 and E1 are executed when “YES” is determined in step E8.
1, E12 is provided with a step of returning without going through.

As described above, when the damping force target value DST obtained based on the control level is set higher than the manually set damping force MDST as shown in FIG. 20, the damping force becomes high. After switching for 2 seconds, the damping force is set to one stage during the roll control hold. As a result, regardless of the damping force set manually,
Since the damping force of the shock absorber 1 is appropriately increased when the roll rigidity is most required for the suspension during the roll control, the roll control at the initial stage of the turning traveling is more effectively performed. In addition, shock absorber 1 is held while maintaining the differential pressure.
Is switched to a damping force that is one step lower, so that it is possible to prevent the riding comfort during that period from being extremely deteriorated. Further, after the holding of the differential pressure is released, the damping force set manually by the occupant is automatically restored, so that it is possible to eliminate the complexity of the occupant restoring the damping force each time.

[Advantage of the Invention] As described above, according to the present invention, the shrinkage is performed according to the larger control target set by the first and second control target setting means based on the steering wheel angular velocity and the lateral acceleration, respectively. Occurs during turning because the supply valve means and the discharge valve means are driven so as to supply the fluid to the fluid spring chamber of the suspension unit on the side and to discharge the fluid from the fluid spring chamber of the suspension unit on the extension side. Of course, the roll can be effectively reduced, and when the control to be executed is first performed according to the first control target set by the first control time setting means, the second control target is executed during the control to be executed. The flow rate control provided in the flow path for supplying the fluid to the fluid spring chamber as compared with the case where the second roll control target set by the setting means is first performed. Since the valve is controlled to increase the flow rate per unit time, the fluid in the fluid spring chamber is quickly supplied to and discharged from the vehicle body roll caused by the steering wheel angular velocity, which has a relatively large roll velocity, and the roll is appropriately rotated. Even if the second control target that can be reduced and is larger than the first control target set after the start of the roll control to be executed is set, the flow control valve maintains the high flow rate state, The effect that the occupant feels uncomfortable because the supply speed of the fluid to the fluid spring chamber changes in the middle of the control that is executed and that the durability deteriorates due to the increased frequency of operation of the flow control valve can be solved.

[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 driven and non-driven state of a three-way valve, and FIG. 3 is a driven state of a solenoid valve. Fig. 4 is a diagram showing the drive and non-drive states of the supply air flow control valve, Fig. 5 is a vehicle speed-steering wheel angular velocity map in SOFT mode, Fig. 6 is a vehicle speed-steering wheel angular velocity map in AUTO mode, and Fig. 7 The figure shows the vehicle speed-steering wheel angular velocity map in SPORT mode, FIG. 8 shows the G sensor map, FIG. 9 shows the relationship between the control level and the air supply / exhaust time based on the vehicle speed-steering wheel angular velocity map, and FIG. 10 shows the control by the G sensor map. Diagram showing the relationship between level and air supply / exhaust time,
FIG. 11 is a schematic flowchart showing the operation of one embodiment of the present invention, FIG. 12 is a detailed flowchart showing a rough road determination routine, and FIG. 13 is a G sensor map at the time of normal and rough road determination. , FIG. 14 is a diagram showing a change in state due to a change in output of the vehicle height sensor, FIG. 15 is a detailed flowchart of a roll control routine, FIG. 16 is a detailed flowchart of a supply / exhaust correction routine, and FIG. 17 is a rear. Internal pressure-front internal pressure characteristic diagram, FIG. 18 is a characteristic diagram of air suspension internal pressure Po and supply / exhaust correction coefficient, FIG. 19 is a detailed flowchart of a damping force switching routine, and FIG. 20 is a diagram showing a temporal change of the damping force. is there. 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.

Front page continuation (72) Shozo Takizawa 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Co., Ltd. (72) Minor Katsumoto 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Within Kogyo Co., Ltd. (56) References Shown 60-155611 (JP, U) Shown 60-152509 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A fluid spring chamber provided for each suspension unit supporting each theory, a fluid supply means for supplying fluid to each fluid spring chamber via a supply valve means, and a fluid supply. A flow rate control valve provided in the flow path and capable of varying the flow rate per unit time, a fluid discharge means for discharging fluid from each of the fluid spring chambers via discharge valve means, and a steering wheel angular velocity detection for detecting a steering wheel angular velocity. Means, an acceleration detecting means for detecting a lateral acceleration acting on the vehicle body, and an angular velocity detected by the steering wheel angular velocity detecting means satisfying a set condition, the first roll control target according to the angular velocity at that time. When the acceleration detected by the acceleration detecting means satisfies the setting condition, the first control target setting means for setting the second roll and the second roll according to the acceleration at that time. A second control target setting means for setting a control target, and a fluid spring of the suspension unit on the compression side according to the larger roll control target of the roll control targets set by the first and second control target setting means. The first control target is the roll control that drives the supply valve means and the discharge valve means so as to supply the fluid to the chamber and discharge the fluid from the fluid spring chamber of the suspension unit on the extension side. When first performed according to the first roll control target set by the setting means, during the roll control to be executed, the second roll control is performed.
Roll control means for controlling the flow rate control valve so that the flow rate per unit time becomes large as compared with the case where the flow rate control valve is initially performed according to the second roll control target set by the control target setting means. A vehicle suspension device characterized by: