JPH0446815A - Roll damping force control device for vehicle - Google Patents

Abstract

PURPOSE:To prevent the diagonal roll of a vehicle and improve the maneuvering stability thereof by detecting steering angular velocity and so controlling a ratio of a front wheel damping force to a rear wheel damping force as to increase, according to the rise of the detected value. CONSTITUTION:A roll damping force controller 36 takes in a detected steering angle and speed signals respectively from a steering angle sensor 33 and a vehicle speed sensor 40, and sends instruction signals if and ir to variable throttle valves 22F and 22R respectively for front and rear wheels, according to the predetermined process, thereby controlling a roll damping force. In this case, respective throttle valves 22F and 22R are so controlled that a roll damping ratio for front wheels becomes larger than a roll damping ratio for rear wheels, according to an increase in detected steering angle. According to the aforesaid construction, a transient pitch component can be restrained even at the time of sudden steering, and the diagonal roll of a vehicle can thereby be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a roll damping force control device for a vehicle that individually controls the roll damping force of front and rear wheels.

[Conventional technology]

BACKGROUND ART Conventionally, as a device capable of suppressing roll motion of a vehicle, there is known, for example, a device proposed by the present applicant and described in Japanese Patent Application Laid-Open No. 60128011 (title of the invention is “Roll Stiffness Control Device for Vehicle”). One aspect of this conventional device is
A variable damping force absorber is installed on each wheel and serves as a roll rigidity variable mechanism that can change the roll rigidity, a steering angle detector detects the steering angle, and a a steering amount calculation means for calculating the steering amount; a steering amount determination means for determining whether the calculated value of the calculation means is greater than or equal to a predetermined value; and when the determination result of the determination means is greater than or equal to the predetermined steering amount; and control means for increasing the roll rigidity of the variable damping force shock absorber of each wheel.

[Problem to be solved by the invention]

However, in the conventional device described above, the damping force of the four wheel metal portions is switched according to the steering angular velocity, so there remains room for improvement in the following points.

In other words, when a vehicle turns, the body normally moves in the roll direction around an axis called the roll axis, which is determined by the structure of the front and rear suspensions. When a vehicle turns by steering, not only a simple roll motion but also a roll motion called a diagonal roll, which combines a pitch motion in which the front of the vehicle also sinks, occurs.

The cause of this diagonal roll is thought to be as follows. When lateral force is generated only on the front wheels at the start of a turn, the front wheels tend to roll first. On the other hand, the characteristics of the Shigok Absorber differ between the compression side and the extension side, and the damping force generated on the extension side is much larger than that on the compression side. The side must stroke wider (faster) than the extended side. As a result, the average wheel stroke of the two front wheels shrinks due to the roll, but since the two rear wheels have not yet rolled, a pitch component occurs in which the front wheels sink, causing the diagonal A roll occurs.

Such diagonal rolls, if the roll amount is large,
Due to non-uniform tire characteristics, handling stability is reduced, and the occupant feels uncomfortable and has a bad feeling.

The present invention was made in view of the unresolved problems of the conventional device, and the problem to be solved is to reliably prevent diagonal roll, further improve steering stability, and The aim is to eliminate the sense of discomfort given to passengers.

(Means for Solving the Problem) In order to solve the above problem, the invention described in claim (1) generates a damping force proportional to the roll angular velocity of the vehicle body and A roll damping force control device for a vehicle in which a damping force generation mechanism capable of changing damping force is installed separately between front wheels, rear wheels, and a vehicle body, includes a steering angular velocity detection means for detecting a steering angular velocity; Front and rear roll damping force control means is provided for controlling each of the damping force generating mechanisms so that the ratio of the damping force of the front wheels to the rear wheels increases as the detection value of the means increases.

Furthermore, as shown in FIG. 1(b), the invention as claimed in claim (2) includes a damping force generating mechanism that generates a damping force proportional to the roll angular velocity of the vehicle body and that can change the damping force. In a vehicle roll damping force control device installed separately between a wheel and a vehicle body, a vehicle speed detection means for detecting vehicle speed, a steering angular velocity detection means for detecting a steering angular velocity, and a detection value of the vehicle speed detection means are increased. front and rear roll damping forces that control each of the damping force generating mechanisms so that the damping force of the front and rear wheels is increased as the value of the steering angular velocity detection means increases, and the ratio of the damping force of the front wheels to the rear wheels increases as the detection value of the steering angular velocity detection means increases and control means.

[Effect]

In the invention described in claim (1), the front and rear roll damping ratio control means controls the damping force generation mechanism of the front and rear wheels in accordance with the detected amount of steering angular velocity by the steering angular velocity detection means to suppress roll. At this time, even if the vehicle speed is the same, the faster the steering and the greater the steering angular velocity, the more the roll damping ratio of the front wheels is controlled to be larger than that of the rear wheels. As a result, the roll rigidity of the front wheels becomes stronger than that of the rear wheels, suppressing the sinking of the front wheels, that is, the pitch component, and preventing the occurrence of diagonal rolls.

Furthermore, in the invention described in claim (2), as the detected value of the vehicle speed detection means increases, the damping force of both the front and rear wheels is increased, so that the overall roll stiffness corresponding to the traveling speed is obtained, and the speed is increased. Pitch components during head turns are also strongly suppressed, and diagonal rolls are also reliably eliminated.

〔Example] The present invention will be described in detail below.

(First Embodiment) A first embodiment of the present invention will be described based on FIGS. 2 to 5 of the accompanying drawings.

In FIG. 2, 2FL to 2RR indicate the front left wheel to the rear right wheel of the vehicle, 4 indicates a wheel support member, and 6 indicates the vehicle body.

One end of a suspension link 8 is swingably connected to the wheel support member 4, and the other end of the suspension link 8 is swingably connected to the vehicle body 6.

A vehicle suspension 9 is installed between each wheel support member 4 and the vehicle body 6, and this suspension 9 includes a shock absorber 10 and a coil spring 12 that are individually provided between each suspension link 8 and the vehicle body 6.
and a hydraulic stabilizer 14 in which an actuator portion is provided between each suspension link 8 and the vehicle body 6. In this embodiment, the stabilizer 14 corresponds to a vehicle roll damping force control device. Each shock absorber 10 is constructed in a conventionally known manner, and generates a damping force on its compression side and expansion side in accordance with the stroke speed.

The stabilizer 14 also includes suspension links 8 for the front, left, and right wheels. ..., 8 and the vehicle body 6, and a control section 14B that controls the roll rigidity of the stabilizer main body 14A when turning.

The stabilizer main body 14A includes hydraulic cylinders 2 as fluid pressure cylinders arranged corresponding to each wheel 2FL to 2RR.
0FL to 20RR, and variable throttle valves 22F and 22R as damping force generating mechanisms arranged in the front and rear, and each of these elements is interconnected by hydraulic piping.

Each of the hydraulic cylinders 20FL to 20RR includes a cylinder tube 20a, a piston 20b that separates the inside of this cylinder tube 20a into an upper cylinder chamber U and a lower cylinder chamber and is slidable inside the tube, and this piston 20b. A piston rod 20 is fixed to the piston rod 20 and extends in the axial direction.
It is configured as a double-acting type with c. In each of the hydraulic cylinders 20FL to 20RR having such a structure, the lower end of the piston rod 20c is attached to the suspension link 8, and the upper end is left in a free state. The ends thereof are swingably supported by the vehicle body 6, whereby hydraulic cylinders 20FL to 20RR are inserted into the upper and lower portions of the front, rear, left and right springs, respectively.

Further, in each of the front wheel side and the rear wheel side, the upper cylinder chamber U of the left wheel side hydraulic cylinder 20FL (20RL) is connected to the right wheel side hydraulic cylinder 20PR via one hydraulic pipe 26A.
(20RR) is connected to the lower cylinder chamber of the left wheel side hydraulic cylinder 20FL (20RL), and the lower cylinder chamber of the left wheel side hydraulic cylinder 20FL (20RL) is connected to the right wheel side hydraulic cylinder 2 through the other hydraulic piping 26B.
It is connected to the upper cylinder chamber U of 0FR (20RR), thereby cross-connecting the cylinders to each other.

Further, hydraulic pipes 26A and 2 are provided on the front wheel side and the rear wheel side, respectively.
6B are connected to each other via variable throttle valves 22F (22R) in the middle. This variable throttle valve 22F,
22R is a well-known method in which the plunger moves according to the value of a command signal i,, i, which is a current value supplied to the electromagnetic solenoid, and this movement energizes the spool valve to vary the orifice diameter. It has a structure. Here, the damping coefficients C, , C, adjusted by the orifice diameter are each proportional to the value of the command signal 'f + lr, as shown in FIG.

On the other hand, the control unit 14B includes a roll damping control controller 36 that controls the damping coefficients C, c of the variable throttle valves 22F and 22R, and a steering angle sensor 38 and a vehicle speed sensor 40 that send detection signals to the controller 36. .

Of these, the controller 36 in this embodiment has a microcomputer, a solenoid drive circuit, etc., and inputs the detection signal θ□ of the steering angle sensor 38 and the detection signal V of the vehicle speed sensor 40 to perform the processing shown in FIG. 4, which will be described later. and outputs a command signal 1t+L to the solenoids of the variable throttle valves 22F and 22R. The steering angle sensor 38 is installed in the steering mechanism, detects a steering angle signal θ8 corresponding to the steering angle and steering direction in the form of a voltage signal, and sends the steering angle signal θ8 to the controller 3.
Supply to 6. Further, the vehicle speed sensor 40 detects, for example, the rotation of the output shaft of the transmission, and outputs a voltage pulse signal ① proportional to the vehicle speed to the controller 36.

Next, the operation of the first embodiment will be explained.

First, the timer interrupt process shown in FIG. 4 executed by the microcomputer of the roll damping control controller 36 will be explained. The process shown in FIG. 4 is executed every predetermined time period Δ. In step (2) in the figure, the microcomputer of the controller 36 reads the detection signal θ□ of the steering angle sensor 38, stores the value, and moves to step (2). In step (2), the rate of change between the previous value and the current value in the read values in step (2) is determined to determine the steering angular velocity θ8. Next, the process proceeds to step (2), where the microcomputer reads the detection signal (2) from the vehicle speed sensor 40, stores the value as a vehicle speed value, and then proceeds to step (2).

In step (2), the current vehicle speed (2) and steering angular velocity 1θ are determined by referring to the characteristic map corresponding to FIG. 5, which is stored in advance in the memory.

Damping command values for the front wheels and rear wheels corresponding to D Ct , D
Set C1. In other words, first select a characteristic curve corresponding to the vehicle speed V, and in that selected curve, the steering angular velocity 1ON
Attenuation command value DC, ,DC uniquely determined corresponding to 1
, is set.

Here, when the front wheel side damping command value DCf and the rear wheel side damping command value DCr in FIG. The side command value DC, is inversely proportional, and both command values DC
The sum of t, DC, is held constant. Therefore, both commands 4KDCt.

The ratio of DC, 'DCt/DC,, J is the steering angular velocity 1 H1
(See the virtual line in FIG. 5). Note that until 1θ, l=lθH1t, DCr <D
I am using Cr. Furthermore, as the vehicle speed V increases,
Command curve DC in FIG.

The form in which DCr is moved upward in parallel, that is, the command value DC,,D
The value of C is increased in proportion to the vehicle speed ■.

Next, the process moves to step (2), and the microcomputer outputs the command values DC, , DC7 set in step (2) to the solenoid drive circuit. As a result, the solenoid drive circuit generates a command signal +t,is proportional to the command value DC,,DC,.
Variable throttle valve 22F.

22R.

In this embodiment, the steering angle sensor 38 and the step
, ■ constitute a steering angular velocity detecting means, the vehicle speed sensor 40 and the process of step ■ in FIG. 4 constitute a vehicle speed detecting means, and the processes of steps ■ and ■ in FIG. This constitutes front and rear roll damping ratio control means.

Next, the overall operation of this embodiment will be explained.

When the vehicle is traveling straight on a smooth road with no unevenness, the vehicle speed sensor 40 detects the signal ■ corresponding to the vehicle speed at that time, but since the detection signal θ8 of the steering angle sensor 38 is zero, the signal shown in FIG. In the process, the steering angular velocity θ□1 also becomes zero. Therefore, the initial value of the command value curve selected according to the vehicle speed at that time, DCr−DCto,DC,=DC,0(DCt
o<DCr. ) is set, the variable throttle valve 22F,
The command signal 1ftIr outputted to 22R also becomes i, <i. As a result, the damping coefficient Or of the rear wheel variable throttle valve 22R becomes larger than that of the front wheel variable throttle valve 22F, and the sum of the two becomes a value proportional to the vehicle speed V.

At this time, when the magnitude of the vehicle speed (2) changes, the damping coefficients C, , C, of the variable throttle valves 22F, 22R are changed in proportion to it, but the ratio 'Cr/CrJ is kept constant.

However, since the suspension stroke does not change now, the hydraulic cylinders 20FL to 20 of the stabilizer 14
There is no stroke variation of the RR, and no hydraulic oil flows through the hydraulic pipes 26A and 26B on both the front and rear sides. Therefore, the stabilizer 14 does not generate a stabilizer effect or damping force due to hydraulic reaction force, and the spring constant set by the suspension 9 is maintained.

For this reason, when a roll starts when turning from the above-mentioned straight-ahead situation, the damping force generated on the rear side of the stabilizer 14 becomes larger than that on the front side, and the steering characteristics tend toward oversteer, resulting in good retrospective performance. can get.

Furthermore, in the above-described straight running, when a bounce occurs in which the left and right wheels move up and down in the same phase, the shock absorber 10 of each wheel generates a damping force proportional to the piston speed. At the same time, in the stabilizer 14, the left and right hydraulic cylinders 20FL, 20FL, 20RL, and 20RR stroke in the same phase, and at this time, the compressed upper cylinder chamber U (lower cylinder chamber L) and the expanded lower cylinder chamber L The volume change of (upper cylinder chamber U) is the same for both rond shapes. Therefore, the compressed upper cylinder chamber U (
Almost all of the hydraulic oil in the lower cylinder chamber L) is transferred via the hydraulic piping 26A (26B) to the extended lower cylinder chamber L (upper cylinder chamber U) of the cylinder on the opposite side of the pair.
As a result, the hydraulic oil does not pass through the variable throttle valves 22F and 22R.As a result, during bounce, only the damping force exerted by each shock absorber 10 damps the vertical vibration of the vehicle body, and the stabilizer 14 absorbs the excess damping force. This does not occur and worsen the riding comfort.

Furthermore, assume that the vehicle is steered from the straight-ahead state described above to a turning state. In that case, the steering angular velocity θi is calculated based on the detection signal θ9 of the steering angle sensor 38, and the front side and rear side damping command values DC, , DC, are set according to the vehicle speed ■ and the steering angular velocity aI4. .

At this time, in the case of a relatively gentle steering state until the steering angular velocity ljHl=j□, the damping command value DC,<D
C, so based on this command, the variable throttle valve 22F,
The damping coefficient Ct, C7 of 22R is also set to Cf <C. Therefore, 4-wheel shock absorber 10. ...,
10 generates a damping force according to the roll of the vehicle body, while
The hydraulic cylinders 20FL to 20RR of the stabilizer 14 also stroke in the left and right opposite phases, and between the left and right cylinders, one pair of cylinder chambers U and L are compressed, and the other pair of cylinder chambers I and IJ are both expanded. be done.

Specifically, we are currently steering to the right, and the left wheel side 2FL2R
When the vehicle body rolls such that L sinks, the upper cylinder chambers U of the left hydraulic cylinders 22FL and 22RL and the lower cylinder chambers of the right hydraulic cylinders 22PR and 22RR are compressed, and at the same time, the left hydraulic cylinders 22FL and 22RL are compressed.
22RL lower cylinder chamber and right hydraulic cylinder 22
The upper cylinder chambers U of FR and 22RR extend together. In the case of a left turn, the opposite compression and expansion occur.

When reaching such a stroke state, the compressed hydraulic fluid passes through the variable throttle valves 22F, 22R and flows into the expanded cylinder chamber on the opposite side, so the variable throttle valves 22F, 22
A damping force is generated according to the orifice diameter of R at that time. In the current state of 1θM+<θH1, this generated damping force is made larger on the rear wheel side to maintain the oversteer tendency and improve turning performance during slow turns.

However, in the case of a sudden steering state with a steering angular velocity of 1θ, 1≧θ, the damping command value D Ct≧D even if the vehicle speed is the same.
C, so based on this command, the variable throttle valve 22F,
22R damping coefficient C,,C.

Also, C2≧C1 is set. Therefore, 4-wheel shock absorber 10. . . , 10 and the damping force of the stabilizer 14 generated as described above, the vehicle body roll is reliably suppressed. Moreover, the damping force generated by the stabilizer 14 at this time is relatively larger on the front side than on the rear side, so that the steering characteristics are maintained in the direction of understeer, and turning stability is maintained, and the front side of the vehicle body rolls. is suppressed more strongly than that on the rear side, eliminating the transient sinking or pinch component on the front side, and also eliminating diagonal roll. Therefore, a decrease in steering stability due to diagonal roll can be prevented, and the occupant's feeling regarding the roll will not be worsened.

In the first embodiment described above, a vehicle speed detection means is provided to determine the roll stiffness in consideration of the vehicle speed, but if necessary, the front and rear roll stiffness can be controlled only by the steering angular velocity θh. is simplified.

In addition, in the first embodiment, during 1θI41<6N, the front and rear damping coefficients are set to C, <C, but if necessary, 1ffnl<l? It is also possible to set Cf>C1 even between o+.

Further, the fluid pressure cylinder used in the roll damping force control device of the present invention is not limited to the double rond type as described above, but may be of the single rond type. In addition, the mounting positions of the fluid pressure cylinders on the wheel side and on the vehicle body side can be opposite to each other on the left and right sides of the vehicle. In this case, the pipes connecting the fluid pressure cylinders will appear to be parallel instead of cross-connected. It becomes a connection.

(Second Embodiment) Next, a second embodiment will be described based on FIGS. 6 to 9.

In FIG. 6, 52FL to 52RR indicate the front to rear right wheels of the vehicle, and 54 indicates a roll damping force control device for the vehicle.

The front suspensions 56FL and 56FR for the front wheels 52PL and 52FR are each configured with a strut type independent suspension system.
FR), a suspension arm 60F elastically connected between the lower end of the knuckle 58F and the vehicle body side member, and a damping force generation mechanism inserted between the upper end of the knuckle 58F and the vehicle body via an elastic body. Variable damping force shock absorber 62FL (62F
R).

In addition, the rear suspensions 56RL and 56RR for the rear wheels 52RL and 52RR are each configured with a parallel link type independent suspension system, and the rear suspensions for the rear wheels 52R
A knuckle 58R attached to L (52RR), a parallel link 60R elastically connected between the lower end of the knuckle 58R and the vehicle body side member, and a damping member inserted between the upper end of the knuckle 58R and the vehicle body via an elastic body. Variable damping force shock absorber 62RL (6
21? R).

The roll damping force control device 54 includes a variable damping force shock absorber 62 that also forms part of the suspension described above.
FL to 62RR, and as shown in FIG. 6, a steering angle sensor 64. Vehicle speed sensor 66 and controller 68
It is composed of

Among these, variable damping force shock absorbers 62FL to 62
Each of the RRs has its damping force set to a high value, for example, in accordance with the excitation current I from the controller 68, similar to that described in, for example, Japanese Patent Laid-Open No. 60-128011.

Switching control can be performed in two low stages.

The steering angle sensor 64 is composed of a potentiometer or the like disposed in the steering mechanism of the vehicle, and sends a detection signal Dθ corresponding to the rotational position of the steering wheel 70 to the controller 6.
Output to 8. That is, the detection signal Dθ becomes a neutral voltage of a predetermined analog amount when the steering wheel 70 is in the neutral position, and when the steering wheel 70 is turned left or right from this neutral position, it becomes lower than the neutral voltage depending on the rotation position. The voltage will either decrease or increase.

The vehicle speed sensor 66 magnetically or optically detects the rotation speed of the vehicle's transmission, propulsion shaft, etc. corresponding to the vehicle speed, and outputs a pulse signal DV having a period corresponding to the rotation speed to the controller 68.

As shown in FIG. 7, the controller 68 includes an A/D converter 72 that converts the input steering angle detection signal Dθ into a digital quantity, and a waveform shaping circuit 74 that shapes the waveform of the input vehicle speed detection signal D■. , a control signal O3 that reads each detection signal Dθ, DV and performs predetermined arithmetic processing to control the damping force.
a microcomputer 76 that outputs a value corresponding to each wheel, and variable damping force shock absorbers 62FL to 62R in response to a control signal C3 from this microcomputer 56.
Drive circuit 78A that supplies excitation current I to solenoid R
~78D. The microcomputer 76 has an interface circuit 79. Arithmetic processing unit 80. The storage device 82 is configured to include at least a storage device 82, and the storage device 82 stores in advance programs, fixed data, etc. necessary for execution of processing by the arithmetic processing device 80, and is capable of storing the processing results over time. There is.

Next, the operation of the second embodiment will be explained.

The arithmetic processing unit 80 is normally running other main programs, and in this state, the 8th
Execute the interrupt processing shown in the figure. In addition, in the main program, in its initial value setting process, the flag Fl, which will be described later, is set.
, F2 is set to "0", and counters CNTa, C
NT! Clear +.

To explain this in detail, in step (3) in the figure, the arithmetic processing unit 80 outputs the steering angle detection signal Dθ converted into a digital quantity.
is read through the interface circuit 79 and the value is temporarily stored. Next, the process moves to step (2), and the steering angle θ is calculated from the read value in step (2) by, for example, referring to a storage table of steering angles θ with respect to preset signal values Dθ. Next, the process proceeds to step (2), where the steering angular velocity θ is calculated from the difference value from the steering angle θ7 at the time of interrupt processing n times before, for example.

Subsequently, the arithmetic processing device 80 advances the process to step (2), and calculates the steering angular velocity θ and the reference steering angular velocity θ calculated in step (2). , it is determined whether lθ1≧6°. Here, the reference steering angular velocity θ. is a value that can discriminate whether or not the steering operation is fast, and is set in advance. For this reason, step ■
When it is determined that ``NO'', that is, lal<j, it is determined that the steering condition is slow, and the process proceeds to step (2), where it is determined whether the flag F1=1.

This flag F1 indicates that a fast steering state is detected based on the steering angle θ, and that at least one of the front side and the rear side is maintained at a high damping force (that is, a hard "H" state).

Therefore, in the judgment of step (2), flag Fl=0. In other words, if both the front side and the rear side have low damping force (that is, soft "L" state), the program returns to the main program and the variable damping force shock absorber 62FL is used.
~62RR maintains the damping force up to that point.

On the other hand, in the judgment of whether ljl≧6° in step ①, r
Assuming that YESJ, that is, a fast steering state is detected,
The process moves to step (2), and it is determined whether the flag F1=■. In this judgment, if rNOJ, that is, Fl=O, then 1θ1<θ in the previous process.

In this case, it is assumed that the state of 181≧00 is reached for the first time in this processing, and then the process moves to steps (2) and (2).

Among these steps, in step (2), the flag F1 is set to indicate a state in which the damping force on the front side is increased in this embodiment. Further, in step (2), the arithmetic processing unit 1F80 outputs only the control signal C5 to the drive circuits 78A and 78B via the interface circuit 79 to the logical value r1. and return to the main program.

Therefore, the excitation current I supplied from the drive circuits 78A and 78B to the solenoids of the variable damping force shock absorbers 62PL and 62FR is turned on, so the damping force of the variable damping force shock absorbers 62FL and 62PR on the front wheel side is high. Set to a predetermined value (hard).

At this time, the variable damping force shock absorber 62 on the rear wheel side
The damping force of RL and 62RR remains low.

Furthermore, rYES in step (2).

That is, in the case of Fl-1, 1θ≧shio in the previous process.

In this case, it is assumed that 1θ1≧60 in this process as well, and then the process moves to step (2). In this step (2), after the counter cNTA is incremented, the process moves to step [phase]. In this step [phase], it is determined whether the count value of the counter cNTA is Lo. Count value L0 is a value corresponding to time T0. Therefore, in step [phase] rNO, that is, Iθ1≧θ. If the predetermined time T0 has not yet elapsed since the state is reached, the program returns to the main program without being involved in either front or rear damping force control, and maintains the damping force state up to that point.

However, in step [phase] rYEsj, that is, Iθ≧
θ. When the predetermined time T0 has elapsed since the state reached, the process moves to steps ① to ②. Among these, step 0
Clear the counter cNTA at step @, and set the flag F2 indicating whether the rear damping force has been set to a high value.
, and in step @, turn the drive circuit 78 on the rear wheel side.
The control signal C8 output to C, 78D is also set to a logical value of "1", and the process returns to the main program. For this reason, the drive circuit 78
Variable damping force shock absorber 62RL from C178D
.

Since the excitation current I supplied to the solenoid 62RR is turned on, the variable damping force shock absorber 62 on the rear wheel side
The damping forces of RL and 62RR are also set to high predetermined values (hard). That is, at this point, the damping forces of the four wheel variable damping force shock absorbers 62FL to 62RR are all set to a high state.

On the other hand, in the judgment in step (2), flag F1=1
．． In other words, if at least one of the front side and the rear side is in a state of high damping force, it will move to the step [phase],
It is determined whether flag F2=1.

Therefore, it is set in step [phase], that is, rYES.”
In this case, the process moves to step (2), where the arithmetic processing unit 80 determines whether the count value of the counter CNT has increased or not. The count value L1 is a value corresponding to time T. If the judgment is "NO" in this step ■, proceed to step ■, increment the counter CNT, and then
Return to the main program.

However, in step (2), rYEs, that is, 1θ decreases θ while repeating the timer interrupt processing at a predetermined period. When it is determined that the set time T has elapsed from the time when , the processes of steps @ to [phase] are performed. Among these, in step O, the counter CNT is cleared, and in step [phase], the flags Fl and F2 are respectively lowered, and the process moves to step [phase].

In this step [phase], the arithmetic processing device 80 connects the drive circuits 78A to 78D via the interface circuit 79.
The control signal C3 to be outputted to is set to the logic value "0" and the process returns to the main program. Therefore, the excitation current I supplied from the drive circuits 78A to 78D to the solenoids of the variable damping force shock absorbers 62FL to 62RR is turned off.
Variable damping force shock absorber for each 4 wheels 62FL~62
The damping force of the RR is set to a low predetermined value (soft).

On the other hand, in the case of rNOJ, F2-0 in Step [Co.], the front damping force has been increased, but the rear damping force remains low.
The process moves to step [phase] and the counter CNTA is incremented. Next, in step ■, the counter CNTA
=L, and in the case of rNo, the processing from step (2) is performed. On the other hand, at step 0, rYEsJ
In this case, set counter CNTA=O in step @,
At step @, [phase], the flag F2 is set in the same manner as in steps @ and ■ above, and a command is given to increase the damping force of the variable damping force shock absorbers 62RL and 62RR on the rear wheel side.

Thereafter, the processing from step (2) onwards is performed.

Since the arithmetic processing unit 80 repeats the above processing, this second
In the embodiment, the steering angle sensor 64. A/D converter 72. 8 constitutes the steering angular velocity detecting means, and the processing of steps ■ to ■ in FIG. 8 constitutes the steering angular velocity detection means, and the steps
78D constitutes front and rear roll damping ratio control means.

Next, the overall operation will be explained with reference to FIG.

First, assume that the vehicle is traveling straight ahead. In this running state, the arithmetic processing unit 80 repeats the routine of returning to the main program through the processing of steps 1 to 2 in FIG. state is maintained.

If we start turning right from this straight-ahead state at a certain time, the detection signal Dθ of the steering angle sensor 64 will start to increase accordingly, and the positive steering angle will increase as shown in FIG. 9 (1). θ is calculated by the arithmetic processing unit 8o. Along with this, the arithmetic processing unit 8o sequentially calculates the varying steering angular velocity θ as shown in (2) in the figure, and the value θ is the threshold value θ. It is being monitored to see whether or not this will be the case.

Then, as shown in FIG. 9, θ≧θ at time t2 due to fast steering (sudden steering). Suppose that the interrupt processing unit 80 reaches this point and performs the processing through steps ① and ② in FIG. 8 in the first interrupt processing. This results in
At time L2, first, the variable damping force shock absorber 62PL on the front side is applied.

A higher damping force (hard: H) of 62FH is commanded (see FIG. 9 (3)). Then, from this time t2, T. At time t3, when time has elapsed, the arithmetic processing device 70 now
Since the processing through steps @ and ■ in Fig. 8 is performed, the rear side variable damping force shock absorber 62RL,
A command is given to increase the damping force (hard: H) of 62RR (see FIG. 9 (4)).

In other words, in the initial state between 10 times t2 and t3, as shown in FIG. 9(5), the front damping force is larger than the rear damping force by a predetermined value, so during that time the damping ratio C, /C, can be increased, and transient diagonal roll during sudden steering can be suppressed. In addition, the steering characteristics tend toward understeer, and the stability at the beginning of a turn becomes better.

Then, from time t onwards, the variable damping force shock absorbers 62FL to 62RR of the four wheels are all set to a high damping force to control the total roll rigidity, so that the roll of the vehicle body is appropriately suppressed, and when turning A good vehicle posture can be obtained. At this time, in this embodiment, as shown in FIG. 9, after time L4, the steering angular velocity is θ<θ. However, the hard suspension state is maintained until time t5, when time T has elapsed, and the rocking back at the end of turning is suppressed (
(See Figure 9 Step [Phase], @)). And time L5
After this has elapsed, all four wheels are returned to a soft damping force state again by steps 1 to 1 in FIG.

Furthermore, assume that after the turning has been completed and the vehicle is turning at a constant steering angle, the steering wheel is operated in the neutral steering direction at time t6 to stop turning to the right. As a result, the changing steering angle θ is detected as shown in FIG. 9(1), so the steering angular velocity θ≦−j. At time t, the process goes through step 2 in FIG. 8 again, and the front damping force is first set to hard, and then T. Time t after hours
8, the rear damping force is set to hard.

Therefore, in the initial stage of turning back between times t7 and t11, the roll stiffness share on the front side becomes larger than that on the rear wheel side, and diagonal roll is prevented, similar to the time at the start of turning described above.

Then, after a certain period of time T0 has elapsed at the time of turning back, the rear side is also applied with a hard damping force, and this state is θ〉-〇. An appropriate roll suppression state is obtained until a certain period of time T has elapsed from the time when (see t8 to tlo in FIG. 9).

By the way, in the above embodiment, the degree of steering is relatively steep and the period during which the steering angular velocity 1jl≧6° is short, so that after one interruption process via step (2) in FIG. 1θ1〈θ. Suppose that it becomes In this case, since rYESJ is obtained in step ① in Fig. 8 and NOJ is obtained in step 0, after the front side is first brought into a hard damping force state, after a predetermined time T0 has elapsed,
In step [phase], the rear side is also automatically set to a hard damping force, and roll is suppressed by the high damping force of the four wheels. As described above, this roll suppression state continues from the time when the front side is set to hard until the time T7 elapses.

In this manner, when making a sharp turn, the same effect as in the first embodiment can be obtained by increasing the damping force on the front wheels earlier than on the rear wheels.

In the second embodiment, it is possible to read the vehicle speed detection signal ■, and the larger the value, the faster the switching time on the front wheel side, and the longer the time T0 for C,>C. It is possible to obtain the same effect as in the example.

Furthermore, the working fluid in the present invention is not limited to the one that uses hydraulic oil as described above, and may be an apparatus that uses, for example, incompressible gas as the working fluid.

〔Effect of the invention〕

As explained above, the present invention is configured such that the ratio of the front wheel side roll damping force to the rear wheel side roll damping force increases as the steering angular velocity increases. Since the damping force against roll on the side wheels is relatively larger than that on the rear wheel side, transient pinch components are suppressed and no diagonal roll occurs, which improves handling stability and improves driver comfort. This has the effect of making the roll feel more natural. In particular, in the invention described in claim (2), as the vehicle speed increases, the overall roll rigidity also increases, so vehicle body roll including diagonal roll can be suppressed with higher precision.

[Brief explanation of drawings]

Figures 1(a) and 1(b) are diagrams corresponding to claims of the claimed invention, respectively;
2 to 5 are diagrams showing the first embodiment of the present invention, in which FIG. 2 is a schematic configuration diagram, FIG. 3 is a graph showing the relationship between the damping coefficient and the command signal, and FIG. 4 is a controller FIG. 5 is a schematic flowchart showing an example of the process, and FIG. 5 is a graph showing an example of changes in the command value with respect to changes in the steering angular velocity. 6 to 9 are diagrams showing a second embodiment of the present invention, in which FIG. 6 is a schematic configuration diagram, FIG. 7 is a block diagram showing the configuration of the controller, and FIG. 8 is a processing by the controller. FIG. 9 is a timing chart showing an example of control. The main symbols in the diagram are 2FL to 2RR...wheels, 6...
- Vehicle body, 8... Suspension link, 9... Vehicle suspension, 10... Shock absorber, 1
4... Stabilizer, 20FL-20RR... Hydraulic cylinder, 22F, 22R... Variable throttle valve, 26A,
26B... Hydraulic piping, 36... Controller, 38
...Steering angle sensor, 40...Vehicle speed sensor, 52FL
~52RR...Wheel, 54...Roll damping force control device, 56FL~56RR...Suspension, 62F
L~62RR...Variable damping force shock absorber, 6
4... Steering angle sensor, 68... Controller.

Claims (2)

[Claims] (1) A roll damping force control device for a vehicle in which a damping force generation mechanism that generates a damping force proportional to the roll angular velocity of the vehicle body and can change the damping force is installed separately between the front and rear wheels and the vehicle body. A steering angular velocity detection means for detecting a steering angular velocity, and a front and rear control mechanism for controlling each of the damping force generating mechanisms so that the ratio of the damping force to the front wheels to the rear wheels increases as the detected value of the steering angular velocity detection means increases. 1. A roll damping force control device for a vehicle, comprising a roll damping force control means. (2) A roll damping force control device for a vehicle in which a damping force generation mechanism that generates a damping force proportional to the roll angular velocity of the vehicle body and can change the damping force is installed separately between the front and rear wheels and the vehicle body. A vehicle speed detection means for detecting a vehicle speed; a steering angular velocity detection means for detecting a steering angular velocity; and as a detection value of the vehicle speed detection means increases, a damping force of the front and rear wheels is increased, and the detection value of the steering angular velocity detection means increases. 1. A roll damping force control device for a vehicle, comprising: front and rear roll damping force control means for controlling each of the damping force generating mechanisms so that the ratio of the damping force of the front wheels to the rear wheels increases as the damping force of the front wheels increases.