JPS62122811A - Suspension control device - Google Patents

Abstract

PURPOSE:To make it possible to restrain vibration having a cycle period around the cycle period of the nonsuspended section of a vehicle upon resonance, by making the characteristics of suspension hard when the detected level of the vehicle exceeds a predetermined value and the cycle period of variation in the vehicle level falls in a predetermined range including the cycle period of the nonsuspended section of the vehicle upon resonance. CONSTITUTION:A vehicle level detecting means M1 delivers a detected vehicle level to a vehicle level judging means M3 and a vehicle level variation cycle period judging means M4. When the judging means M3 determines that the vehicle level M1 exceeds a predetermined value and further the judging means M4 determines that the cycle period of variation in the level of the vehicle falls in a predetermined range including the cycle period of the nonsuspended section of the vehicle upon resonance, the result thereof is delivered to a control means M5. Then, the control means M5 delivers a control signal in accordance with the result of the determination to a suspension characteristic changing means M2 to make the characteristic of suspension hard. With this arrangement, vibration having a cycle period around the cycle period of the nonsuspended section of the vehicle upon resonance may be restrained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a suspension control device for a vehicle, and more specifically, the present invention relates to a suspension control device for a vehicle. The present invention relates to a suspension control device that suppresses suspension.

[Prior Art] The characteristics of springs, shock absorbers, stabilizers, and bushings as components of the suspension provided between the wheels and the body of a vehicle, such as spring constant, damping force, rigidity, etc., are different from those of conventional vehicles. It was determined based on various conditions considered from the aspects of ride comfort, maneuverability, and stability. However, in recent years, based on the results of vehicle driving experiments, emphasis has been placed on improving ride comfort under certain conditions, and improving maneuverability and stability under other conditions, depending on road surface conditions or vehicle driving conditions. Accordingly, suspension control devices have been developed that change the above-mentioned suspension characteristics in order to achieve both contradictory performances. For example, a ``variable shock absorber device'' increases the damping force of the shock absorber to maintain good driving conditions when the loaded weight increases or when driving on rough roads.
-30542@publication), and for example, a "vehicle height adjustment device" (Japanese Patent Laid-Open No. 138406/1983) that automatically adjusts the vehicle height to a high vehicle height on rough roads and a low vehicle height on flat roads. Proposed.

[Problems to be Solved by the Invention] The suspension control device as the prior art includes:
The following problems were encountered. In other words, (1) When driving at a relatively high speed on a continuously rough road, that is, a paved road or an unpaved road with many unevenness such as road joints, the cycle is close to the cycle during unsprung co-transportation. Photography (frequency 10
~15[H4F) is often produced. Such imaging deteriorates the ground contact performance of the tires, which causes the rear wheels to skid, for example, when the vehicle turns, reducing maneuverability and stability. Further, vertical movements that are uncomfortable for the occupants also occur, resulting in poor ride comfort. However, in the past, the suspension characteristics were changed by determining whether the vehicle was traveling on a rough road based only on the magnitude of the width of the vehicle height photograph. For this reason, there is a problem in that it is not possible to promptly detect vibrations having a period close to the period at the time of unsprung resonance as described above and change the suspension characteristics.

(2) Furthermore, the suspension characteristics that are effective in each case are different between a case where an image has a period close to the period at the time of unsprung resonance and a case where an image has a period other than that. Generally, for vibrations with a period close to that of unsprung resonance, the suspension characteristics are changed to a harder state to improve ground contact, while for imaging with other periods, the suspension characteristics are changed to a harder state. It is desirable to change it to a softer state to absorb shock. However, in the past, suspension characteristics were not changed in consideration of the imaging cycle, so there was a problem in that appropriate suspension control was not performed in response to vibrations.

An object of the present invention is to provide a suspension control device that is effective in suppressing imaging having a period close to the period at the time of unsprung resonance.

Configuration of the Invention [Means for Solving the Problems] In order to solve the above problems, the present invention adopts the configuration illustrated in FIG. 1. That is, as illustrated in FIG. 1, the present invention includes: a vehicle height detection means M1 that detects the distance between the wheels and the vehicle body as the vehicle height; and a suspension characteristic change means M2 that changes the suspension characteristics in response to an external command. and a vehicle height determining means M3 for determining whether or not the vehicle height detected by the vehicle height detecting means M1 exceeds a predetermined value; The period determining means M4 determines whether the vehicle height is within a predetermined range including the period at the time of lower resonance, and the vehicle height determining means M3 determines that the vehicle height exceeds a predetermined value, and the period determining means M4 determines whether the vehicle height falls within a predetermined range. The present invention is characterized by comprising a control means M5 that outputs a command to change the suspension characteristics to a harder state to the suspension characteristics changing means M2 when it is determined that the period of change in the vehicle height is within a predetermined range. The gist of this paper is a suspension control device.

The vehicle height detection means M1 detects the distance between the wheels and the vehicle body as the vehicle height. For example, the displacement of the suspension arm relative to the vehicle body may be changed into a rotation amount, and the rotation amount may be detected by a potentiometer and output as an analog signal. Alternatively, for example, the rotation amount may be detected by a well-known rotary encoder and output as a digital signal.

The suspension characteristic changing means M2 is for changing suspension characteristics. For example, the spring constant of the suspension, the damping force of the shock absorber, the stiffness of the bushing,
It is also possible to configure the stabilizer rigidity etc. to be changed in multiple steps or steplessly.

That is, in an air suspension or the like, the spring constant may be changed in size by communicating or blocking the main air chamber and the sub-air chamber. Further, for example, the damping force can be increased or decreased by changing the diameter of the orifice through which the oil of the shock absorber flows. For example, can you make the suspension characteristics stiffer by changing the stiffness of the bushings or the stabilizer? ffi
It is also possible to change to (HARD), a slightly hard state (SPORT), or a soft state (SOFT).

The vehicle height determining means M3 determines whether the vehicle height exceeds a predetermined value. For example, the absolute value of the detected vehicle height may be compared with a predetermined vehicle height and the result may be output.

Period determination means M4 means that the period of change in vehicle height is unsprung.]
It is determined whether the period is within a predetermined range that includes the period of the dragon hour. For example, it is also possible to calculate the cycle by measuring the time from the maximum value to the minimum value of the change in vehicle height, that is, half a cycle, and to output the result by comparing it with the above-mentioned predetermined range.

The control means M5 outputs a command to change the suspension characteristics to a harder state when the vehicle height exceeds a predetermined value and the period of change is within a predetermined range including the period at the time of unsprung resonance. It is.

The vehicle height determining means M3, the cycle determining means M4, and the control means M5 may be realized as independent discrete logic circuits, for example. Further, for example, it may be configured as a logical operation circuit from a CPU, ROM, RAM, and other peripheral circuit elements, and implement the above-mentioned means according to a predetermined processing procedure.

[Function] As illustrated in FIG. 1, the suspension control device of the present invention is configured such that the vehicle height determining means M3 determines that the vehicle height detected by the vehicle height detecting means M1 exceeds a predetermined value, and
When the period determining means M4 determines that the period of change in vehicle height is within a predetermined range including the period at the time of unsprung resonance, the control means M5 issues a command to change the suspension characteristics to a harder state to the suspension characteristics changing means M2. It works to output to.

Therefore, the suspension control device of the present invention works to promptly detect and suppress vibrations when vibrations of a predetermined value or more and having a period within a predetermined range including the period at the time of unsprung resonance occur. As described above, each component of the present invention functions to solve the technical problem of the present invention.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail based on the drawings.

FIG. 2 shows an automobile suspension control device using an air suspension, which is an embodiment of the present invention.

) 11R represents a right front wheel height sensor provided between the right front wheel and the vehicle body, and detects the distance between the right suspension arm that follows the movement of the wheel and the vehicle body. H
1L represents a left front wheel height sensor provided between the left front wheel and the vehicle body, and detects the distance between the left suspension arm and the vehicle body.

H2C represents a rear wheel height sensor provided between the rear wheels and the vehicle body, and detects the distance between the rear suspension arm and the vehicle body. Vehicle height sensor H1R.

Short cylindrical main bodies 1Ra and 1La of 81L and 82G.

1Ca is fixed to the vehicle body side, and the main bodies 1Ra, 1La, 1
Links 1Rb, 1Lb, in a direction approximately perpendicular to the central axis of Ca.
1Cb is provided. The link IRb, 11b, 1
At the other end of Cb are turnbuckles 1RC, ILC, 1cc.
is rotatably attached, and furthermore, the turnbuckle 1Rc.

The other ends of 11C and 1CG are rotatably attached to a part of each suspension arm.

In addition, a plurality of photointerrupters are arranged in the main body of the vehicle height sensors H1R, H1L, and H2C, and a disc plate having a slit coaxial with the center axis of the vehicle height sensor switches the photointerrupters from 0N10FF according to changes in vehicle height. By doing so, changes in vehicle height are detected as 4-bit vehicle height data, and a digital signal is output.

31 L, S1R, S2L, S2R are front left and right respectively.
This shows the air suspension installed on the rear wheels. The air suspension 32L is installed in parallel with a suspension spring (not shown) between the suspension arm of the left rear wheel and the vehicle body.

The air suspension 32L is composed of a main air chamber 52La and a sub air chamber 52Lb that perform an air spring function, a shock absorber 32LC, and an actuator A2L that changes the air spring constant or shock absorber damping force. S1L, S1R, and S2R also represent air suspensions with similar configurations and functions, with air suspension 31m on the left front wheel and air suspension S on the left front wheel.
1R is installed on the right front wheel, and air suspension S2R is installed on the right rear wheel.

10 is each air suspension S1L, S1R.

The compressed air supply/discharge system for the air springs S2L and S2R is shown, and a compressor 1ob is operated by a motor 10a to generate compressed air. This compressed air is guided to the air dryer 10d via the check valve 10c. The check valve 10c connects the compressor 10b to the air dryer 10.
The direction toward d is defined as the forward direction. air dryer 10
d is each air suspension 31 L, S1R, S2L,
Dry the compressed air supplied to S2R, and dry the air piping and each air suspension 31L, S1R, S2L, S2R.
The components of each air suspension 51L, S1R, S2L are protected from moisture.

Main air chamber S1 La, 31Ra, 52La of S2R.

52Ra and auxiliary air chambers 51Lb, 51Rb, 52L
b, prevents abnormal pressure due to phase change of moisture inside 52Rb. The check valve of the fixed throttle check valve 10e is connected to each air suspension S1L from the compressor 10b,
The direction toward S1R, S2L, and S2R is defined as the forward direction. In the fixed throttle-equipped check valve 10e, the check valve part opens when compressed air is supplied, and the check valve part closes when compressed air is discharged, and the compressed air is discharged only from the fixed throttle part. The exhaust valve 10f is a 2-point, 2-position spring offset type solenoid valve. The exhaust valve 10f is normally the second valve.
It is located at the position shown in the figure and is in a blocked state, but when compressed air is discharged from the air suspensions SIL, 31R, S2L, and S2R, it is switched to the communicating state shown in the position on the right side of Figure 2, and the fixed orifice is reversed. Compressed air is discharged into the atmosphere via a stop valve 10e and an air dryer 10d.

Vl L, VlR, V2L1 V2RL1: These are air spring supply and exhaust valves that perform a vehicle height adjustment function, and are respectively disposed between each air suspension SIL, SIR, 32L, and S2R and the compressed air supply and exhaust system 10 described above. There is.

The air spring supply and exhaust valve ■1 L, VlR, V2L, V
2R is a 2-point, 2-position spring offset type solenoid valve. Normally it is in the position shown in Figure 2 and is in the shut off state, but when adjusting the vehicle height, it is in the position shown in Figure 2 above. Switched to communication state. That is, when the air spring supply and exhaust valves V1L, VlR, V2L, and V2R are brought into communication, the main air chambers 31La,
51Ra, 52La, 52Ra and compressed air supply and exhaust system 10
When air is supplied, the volume of the main air chambers S1 La, 31Ra, 52La, 52Ra increases and the vehicle height becomes higher, and when air is exhausted due to the weight of the vehicle, the volume decreases. Vehicle height is lowered. Furthermore, when the air spring supply and exhaust valves V1L, VIR, V2L, and V2R are turned off, the vehicle height is maintained at the vehicle height at that time. In this way, the above-mentioned exhaust valve 10f of the compressed air supply and exhaust system
and each of the above air spring supply and exhaust valves V1L, V1R, V2
By performing LSV2R (7) communication/blocking control, it is possible to adjust the vehicle height by changing the volumes of the main air chambers 51La, 51Ra, 52La, and 52Ra of the air suspensions SIL, S1R, S2L, and S2R. be.

SEI is a vehicle speed sensor installed inside the speedometer, and outputs a signal according to the vehicle speed. ' Each signal from the vehicle height sensors H1L, HIR, H2C and vehicle speed sensor SEI described above is sent to the electronic control unit (hereinafter referred to as EC).
It's called 1J. )4. ECU4 inputs these signals, processes the data, and controls air suspension actuators A1L, AlR, A2L, A2R1 air spring supply and exhaust valves V1L, V1R1V2L, V2R1 compressed air supply and exhaust valves to perform appropriate control as necessary. A drive signal is output to the system motor 10a and the solenoid of the exhaust valve 10f.

Next, based on FIGS. 3 and 4, the air suspension 31
The configurations of the main parts of L, SIR, S2L, and S2R will be explained. Since each air suspension has a similar configuration, the right rear wheel air suspension S2R will be described in detail.

As shown in FIG. 3, this air suspension S2R includes a shock absorber 52Rc consisting of a conventionally well-known piston/cylinder, and a shock absorber 52Rc.
and an air spring device 14 provided in association with the 2RC.

Cylinder 12 of shock absorber 52RC (buffer)
An axle (not shown) is supported at the lower end of a, and a piston rod 12b extending from a piston (not shown) slidably disposed within the cylinder 12a is supported at the upper end of the piston rod 12b. A cylindrical elastic assembly 18 for elastically supporting the vehicle body 16 is provided. In the illustrated example, the shock absorber 52RC is a conventionally well-known variable damping force shock absorber whose damping force can be adjusted by operating a valve function provided on the piston. A control rod 20 is disposed within the piston rod 12b in a fluid-tight and rotatable manner via a seal member 22.

The air spring device 14 includes a peripheral wall member 26 including a bottom portion 26a provided with an opening 24 that allows the piston rod 12b to pass therethrough, and a peripheral wall portion 26b rising from the edge of the bottom portion, and a peripheral wall member 26 that is arranged to cover the peripheral wall member 26 and is attached to the vehicle body. an upper housing member 28a fixed to the upper housing member 28a;
The chamber 32 includes a lower housing member 28b with an open lower end connected to the lower end of the lower housing member 28b, and a diaphragm 30 made of an elastic member that closes the lower end of the lower housing member 28b. The chamber 32 has an opening 34 corresponding to the opening 24 provided in the bottom 26a of the peripheral wall member, and is connected to a lower main air chamber 52Ra and an upper sub air chamber by a partition member 36 fixed to the bottom 26a. 52Rb, and rain air chambers 52Ra and 52Rb are filled with compressed air. Partition wall member 3
6 is provided with a conventionally well-known buffer rubber 40 that can come into contact with the upper end of the cylinder 12a, and the buffer rubber 40
A passage 42 is formed in the main air chamber 52Ra for communicating the openings 24 and 34 with the main air chamber 52Ra.

The cylindrical elastic assembly 18 is arranged around the piston rod 12b inside the circumferential wall member 26 that constitutes the inner circumferential wall of the sub air chamber 52Rb in the circumferential wall 26b. rain air chambers 52Ra and 52Rb
A valve device 44 is provided to control communication between the two.

The cylindrical assembly 18 includes an outer cylinder 18a, a cylindrical elastic body 18b, and an inner cylinder 18C, which are arranged concentrically with each other,
The cylindrical elastic member 18b is fixed to both cylinders 18a and 18c. The outer cylinder 18a of the cylindrical assembly 18 is press-fitted into the peripheral wall portion 26b of the peripheral wall member 26 fixed to the vehicle body via the upper housing member 28a. Also,
A valve number body 44a of the valve device 44, which allows the piston rod 12b to pass therethrough, is fixed to the inner cylinder 18G, and since the piston rod 12b is fixed to the valve number body 44a, the piston rod 12b is fixed to the valve number body 44a. It is elastically supported by the vehicle body via a cylindrical elastic assembly 18. An annular air seal member 4 is provided between the outer cylinder 18a and the peripheral wall portion 26b.
6, and the space between the piston rod 12b and the valve number chamber 448 is sealed by an annular air seal member 48. In addition, the inner cylinder 18c and the valve number body 44
A is sealed by an annular air seal member 50.

A hole 52 that extends parallel to the piston rod 12b and is open at both ends is formed in the valve number body 44a, and a rotary valve body 44b is rotatably housed in the hole.

The rotary valve body 44b includes a main body portion 56a that can abut against a lower positioning ring 54a disposed at the lower end of the hole 52, and a small diameter masterpiece that protrudes above the cylindrical elastic assembly 18 from the main body portion. 56b. Said hole 5
An upper positioning ring 54b that cooperates with the lower positioning ring 54a to prevent the rotary valve body 44b from falling out of the hole 52 is disposed at the upper end of the upper positioning ring 54b. An annular seal base 60 having an inner air seal member 58a and an outer air seal member 58b for sealing the hole 52 is disposed therebetween. Further, there is a space between the seal base 60 and the main body portion 56a of the rotary valve body 44b, which facilitates the rotational movement of the rotary valve body 44b when the main body portion 56a of the valve body is suppressed by the seal base 60 due to air pressure. A friction reducing member 62 is arranged for this purpose.

Below the cylindrical elastic assembly 18 is the opening 24.34.
and the main air chamber 52Ra through the passage 42 of the buffer rubber 40.
A chamber 64 is formed in the main body portion 56a of the rotary valve body 44b.
A recess 66 is formed which is open to. Further, a communication passage 68 is formed in the main body portion 56a, passing through the main body portion in the diametrical direction and crossing the recess 66.

The collection container 56b that receives the valve body 56a has a fourth
As clearly shown in the figure, a pair of ventilation passages 70 are provided, one end of which can communicate with the communication passage 68, respectively.
The air passages extend outward in the diametrical direction of the hole 52 on substantially the same plane toward the outer peripheral surface of the rotary valve body 44b, and each air passage 7
0 is open to the outer peripheral surface of the collecting container 44a through a seat hole 72.

Further, between the pair of ventilation passages 70 in the circumferential direction of the hole 52, a ventilation passage 74 whose one end can be communicated with the communication passage 68 is arranged so that the ventilation passage 74 and the ventilation passage 70 are substantially on the same plane toward the outer circumferential surface of the collection container 44a. Stretch. The diameter of the ventilation passage 74 is smaller than that of the ventilation passage 70, and the other end of the ventilation passage 74 has a seat hole 75.
It opens to the outer circumferential surface of the collection container 44a. On the inner circumferential surface of the inner cylinder 18c that covers the outer circumferential surface of the collection container 44a,
An annular groove 76 is formed surrounding the outer peripheral surface of the collecting container 44a to communicate the seat holes 72 and 75 of the ventilation passages 70 and 74.

The inner cylinder 18G is formed with an open lower part 8 that opens into the groove 76 forming an annular air passage, and the cylindrical elastic member 18b has an elastic part corresponding to the open lower part 8. A through hole 80 is formed that extends radially outward. Further, each through hole 80 opens to the outer peripheral surface of the outer cylinder 18a through an opening 82 provided in the outer cylinder 18a. Accordingly, the open lower portion 8 82 and the through hole 80 define an air passage corresponding to the air passage 70 and passing through the cylindrical elastic assembly 18 .

The open lower part 8.82 and the through hole 80 are connected to the sub air chamber 5.
2Rb, the auxiliary air chamber 52Rb is provided on the outer peripheral surface of the peripheral wall portion 26b of the peripheral wall member that covers the outer cylinder 18a.
A plurality of openings 84 are provided at equal intervals in the circumferential direction. In order to communicate all the openings 84 with the opening lower part 8.82 and the through hole 80, an annular groove 86 is formed on the outer circumferential surface of the outer cylinder 18a to surround the outer cylinder at the part where the opening 82 opens. The opening 84 opens into the groove 86 forming an annular air passage.

In the example shown in FIG. 4, the open lower lower part 8.82 and the through hole 80 are provided corresponding to the two ventilation passages 70 of the collection container 44a, but between the inner cylinder 18c and the collection container 44a. Since the annular air passage 76 is formed in which the air passages 70 and 74 communicate with each other, the elastic member 18
The air passage can be formed at a desired position in the circumferential direction of b.

Referring again to FIG. 3, the upper end of the piston rod 12b is provided with a control rod 20 for adjusting the damping force of the shock absorber 52RC and a control rod 20 for rotating the rotary valve body 44b of the valve device 44, which is conventionally used. A known actuator A2R is provided, and the rotary valve body 44 is actuated by this actuator A2R.
b is rotated.

This air suspension S2R is configured as described above and has the following effects.

First, the rotary valve body 44b is held in the closed position as shown in FIG. Then, the communication between the sub air chamber 52Rb and the main air chamber 52Ra is cut off, so that the spring constant of the suspension S2R is set to a large value.

Further, the communication path 6 of the valve body is controlled by the actuator A2R.
8 is operated to a position where it communicates with the large-diameter ventilation passage 70 of the valve number body 44a, the main air chamber 52Ra has the communication passage 68 communicating with the air chamber, the large-diameter ventilation passage 70, and the elastic The open lower part 8, the through hole 80 and the opening 82 of the assembly 18
Since the suspension S2R communicates with the auxiliary air chamber 52Rb through 84 and 84, the spring constant of the suspension S2R is set to a small value.

Further, when the communication passage 68 of the rotary valve body 44b is operated to a position communicating with the small diameter ventilation passage 74 of the valve number container 44a by adjusting the actuator A2R, the main air chamber 5
2Ra is the communication passage 6 communicating with the main air chamber 52Ra.
8. It communicates with the sub air chamber 52Rb through the small diameter ventilation passage 74, the air passage 76, the open lower portion 8 of the elastic assembly 18, the through hole 80, and the openings 82 and 84. Since the small-diameter ventilation passage 74 provides greater air resistance than the large-diameter ventilation passage 70, the suspension S2R
The spring constant of is set to an intermediate value.

Next, the configuration of the ECU 4 will be explained based on FIG.

The ECU 4 is a central processing unit (hereinafter referred to as CPU) 4a1 that inputs and calculates data output from each sensor according to a control program, and performs processing for outputting control signals to various devices. Read-only memory (hereinafter referred to as ROM) in which programs and initial data are stored >4b, ECt
Random access memory (hereinafter referred to as RAM) is used to read and write data input to J4 and data necessary for arithmetic control. It is stored in a battery so that it retains the necessary data even after the key switch of the car is turned off. Backup random access memory backed up (
Hereinafter referred to as backup RAM. >4d, which is configured as a logic operation circuit, includes an input port (not shown), a waveform shaping circuit provided as necessary, and a multiplexer that selectively outputs the output signals of the above-mentioned sensors to the CPU 4a, and It is equipped with an input section 4e equipped with an A/D converter etc. that converts an analog signal into a digital signal, an output port (not shown), and, if necessary, a drive circuit etc. that drives each of the above-mentioned actuators according to a control signal of the CPJJ 4a. It is equipped with an output section 4f.

The ECU 4 also connects each element such as the CPU 4a, the ROM 4b, the input section 4e, and the output section 4f, and a path line 4Q to which each data is sent.
It has a clock circuit 4h that sends a clock signal serving as control timing to the AM4C or the like at predetermined intervals.

If the vehicle height sensors HIL, HIR, and H2C described above are vehicle height sensors that output digital signals composed of a plurality of photointerrupters used in this embodiment, for example, as shown in FIG. via CPU4a
can be connected to. For example, if it is necessary for vehicle height sensors HIL, H1R, and H2C that output analog signals, a configuration as shown in FIG. 7 can be adopted, for example.

In this case, the vehicle height value is sent to the ECU4 as an analog voltage signal.
is input to CPtJ4, is converted into a digital signal by A/D converter 4e2, and is sent to CPtJ4 via path line 4g.
transmitted to a.

Next, suspension control processing executed by the ECU 4 will be explained based on the flowchart shown in FIG. In this suspension control process, after the vehicle starts and accelerates, it shifts to a steady running state in which the vehicle speed V is in the range of 30 to 80 [Km/h], and the driver selects the auto mode (ALJT).
When O> is selected, it is activated and executed repeatedly. Note that while this suspension control process is being executed, a vehicle height detection process (not shown) is interrupted and executed by a software timer at an appropriate time. Through this vehicle height detection process, the vehicle height is sequentially detected from the left and right front wheel height sensors (IL,)-11R and the rear wheel height sensor H2C at predetermined time intervals (in this example, 3 [m5ec]). Front wheel height data HF and rear wheel height data converted to the amount of displacement from the standard vehicle height position) (H
Both data are constantly updated. Therefore, the latest vehicle height data and the previous vehicle height data detected just before the latest vehicle height data are always stored in predetermined areas in the RAM 4c.

This suspension control process is executed in such an environment. First, an overview of this process will be explained.

(1) It is determined whether the latest rear wheel height data HR (here, the amount of displacement of the vehicle height from the standard vehicle height position) is equal to or greater than the rear wheel amplitude determination reference value Ho (step 100).

(2) Based on the judgment in (1) above, the rear wheel amplitude judgment reference value H
If it is determined that the value is O or above, the rear wheel is in a downward position (rebound) or is in a riding position (bound).
(step 105).

(3) If it is determined that the rear wheels are in the lowered state based on the determination in (2) above, after confirming that the front wheel vehicle height data HF is equal to or higher than the front wheel amplitude determination reference value 81, The period is measured, and the half period is equal to or greater than the minimum half period TC for unsprung resonance determination and the maximum half period TD for unsprung resonance determination.
If the following is true, change the suspension characteristics to the hard state (
HARD) (steps 110, 115, 12
5.130, 140, 155, 160, 165).

(4) On the other hand, if it is determined that the rear wheel is in a riding state based on the determination in (2) above, the front wheel height data HF is equal to or greater than the front wheel height determination reference value H1, as in (3) above. After confirming that, if the half period of the commotion is measured and the half period is equal to or greater than the minimum half period TC for unsprung judgment, and less than the maximum half period TD for unsprung judgment, the suspension is suspended. The characteristics are changed to the hard state (HARD) (steps 310, 315, 325, 330, 340° 355, 360, 365).

(5) After changing the suspension characteristics to the hard state (HARD) in (3) or (4) above, start timing, and then, before the return reference time TA elapses, the rear wheel vehicle height data HR determines the rear wheel amplitude. If the reference value HO is not exceeded, the suspension characteristics are changed to a soft state (SOFT) (step 170°370.100,400,405>).

Next, details of this suspension control processing will be explained.

First, in step 100, it is determined whether the absolute value of the rear wheel height data HR is greater than or equal to the rear wheel amplitude determination reference value Ho. Here, the rear wheel height data HR is the amount of displacement from the standard vehicle height position detected at predetermined intervals, and is the latest detected data. Since it is the amount of displacement from the standard vehicle height position, it has positive and negative signs. If the rear wheel rides on or off an unevenness on the road surface having undulations of a predetermined degree or more, the absolute value of the rear wheel vehicle height data HR goes around the rear wheel amplitude determination reference value Ho by one time, so the process proceeds to step 105.

In step 105, whether the rear wheel height data HR is positive or negative is determined. In other words, the rear wheel vehicle height data HR is the amount of displacement from the standard vehicle height position, so if the rear wheel rides down into a depression in the road surface, the distance between the wheel and the vehicle body increases, so the rear wheel vehicle height The height is larger than the standard vehicle height position, and the rear wheel vehicle height data HR takes a positive value. On the other hand, if the rear wheels run onto a convex part of the road surface, the distance between the wheels and the vehicle body becomes smaller, so the rear wheel height becomes a value smaller than the standard vehicle height position, and the rear wheel height data HR takes a negative value. Take. If the rear wheel rides down, the process proceeds to step 110, and if the rear wheel rides up, the process proceeds to step 310. In either case, the following processing is the same, so we will continue with the following 31 steps assuming the case where the rear wheel gets on and off.

In step 110, it is determined whether the latest rear wheel height data HR is greater than or equal to the previously detected rear wheel height data HRb. That is, since both data HR and HRb are constantly updated at predetermined intervals, if this determination is continued, the latest rear wheel height data HR will become the previously detected rear wheel height data H.
f? It becomes possible to detect the point in time when the rear wheel height data HR reaches its maximum value. The same steps are repeated until the maximum value of the latest rear wheel height data HR is detected.

When the maximum value is detected, the process proceeds to step 115. Here, it is determined whether the absolute value of the latest rear wheel height data H'' is greater than or equal to the front wheel amplitude determination reference value H1.

That is, if the change in the vehicle height of the rear wheels described above is a temporary impact caused by a single unevenness on the road surface, the front wheel height data HF does not show a very large change. On the other hand, if the above-mentioned rear wheel vehicle height displacement is due to vibration caused by continuous driving on rough roads, the above-mentioned front wheel vehicle height data H" also shows a large change. Therefore, according to the determination in step 115, the vehicle It is possible to determine whether the vehicle is in a state where a sudden impact has been applied or whether the vehicle is in a state where continuous imaging has occurred.If the vehicle is in a state where a single impact has been applied, step 120 , change the suspension characteristics to the soft state (S
OFT). That is, actuators A1R, A1L, A2R, and A2L are driven to drive air suspensions S1R, S1L, and S2R.

S2L main air chamber 31Ra, SI La, 52Ra.

52La and auxiliary air chambers 51Rb, 311b, 52Rb, 8
2Lb through a large-diameter air passage 70 to reduce the spring constant of the air spring, and to rotate the control rods 20 of the shock absorbers 51Rc, 51Lc, 52Rc, and 52Lc to reduce the damping force. . Thereafter, the process returns to step 100 above.

On the other hand, if the vehicle is in a continuous shooting state, the process proceeds to step 125. Here, the boarding detection time timer T
After 2 is reset, timing starts. In other words,
Latest rear wheel height data H detected in step 110 above
The time is measured from the time when R takes the maximum value. In the subsequent step 130, it is determined whether the latest rear wheel vehicle height data l''R is less than or equal to a value obtained by inverting the sign of the rear wheel width determination reference value HO. In other words, the latest rear wheel height data HR is lower than the standard vehicle height position by the rear wheel amplitude determination reference value Ho.
A determination is made as to whether or not the value exceeds , and becomes a roughly small value. This is because if the vibrations of the vehicle are periodic, it is expected that the rear wheels in the lowered state (detected in step 110) will shift to the mounted state as time passes, so this time, on the contrary, the rear wheels will shift to the mounted state. This is intended to detect the movement of the rear wheel that is likely to shift by comparing the sign-inverted rear wheel amplitude determination reference value HO with the latest rear wheel height data HR. If the latest rear wheel height data does not become less than the sign-inverted rear wheel amplitude determination reference value HO, step 135
Proceed to. Here, it is determined whether the counted value of the run-over detection time timer T2, which started counting in step 125, has become equal to or greater than the detection reference time T8. If the detection reference time T8 has not yet elapsed, step 1 above is performed.
The process returns to step 30, and detection of rear wheel riding is repeated again. On the other hand, if the rear wheel is not detected to be riding on the rear wheel by a distance equal to or higher than the rear wheel width determination reference value HO even after the reference time TB has elapsed, the vibration detected in step 100 is one-off and continues. It is determined that the image is not photographed, and the process returns to step 100 described above.

Here, the following explanation will be continued assuming that the rear wheel has been detected in step 130 within the detection reference time TB. In this case, the process proceeds to step 140, where it is determined whether the latest rear wheel height data HR is less than or equal to the previously detected rear wheel height data HRb. Through this processing, it is possible to detect the time when the latest rear wheel height data HR takes the minimum value, similarly to step 110 described above. The same steps are repeated until the minimum value of the latest rear wheel height data IR is detected. When the minimum value is detected, the process proceeds to step 155. Here, it is determined whether the counted value of the ride detection time timer T2, which started counting in step 125, is equal to or greater than the minimum half cycle TC for determining unsprung co-pregnancy. That is, the time from when the rear wheel height detected in step 110 reaches its maximum value to the time when the rear wheel height detected in step 140 reaches its minimum value (corresponding to a half period of the detected vibration) ) is counted by the run-over detection time timer T2, so it is determined whether or not the currently detected imaging has a specific period. This minimum half-cycle TC for determining unsprung co-pregnancy corresponds to a vibration with a frequency of approximately 15 [H2], and is set to approximately 0.035 [seC] in this embodiment. If the count value of the run-over detection time timer T2 is equal to or greater than the minimum half cycle TC for unsprung resonance determination, the process proceeds to step 160. Here, it is determined whether the count value of the ride detection time timer T2 is less than or equal to the maximum half period TO for unsprung joint photography determination.

In other words, it is determined whether the currently detected imaging has a specific period. The maximum half period TO for unsprung resonance determination corresponds to a vibration of approximately 10 [H4F] in frequency, and is set to approximately 0.05 [SeC] in this embodiment.

If the count value of the run-over detection time timer T2 is less than or equal to the maximum half period TO for unsprung co-photography determination, the process proceeds to step 165.

Step 165 is executed when it is determined that the vibration state of the vehicle is in the unsprung shared shooting state, and here, processing is performed to change the suspension characteristics to a hard state (HARD>. That is, actuator A1R, A
Driving IL, A2R, and A2L, air suspension SIR, 31m.

Main air chamber 51Ra, Sl La of S2R, 82L.

S, 2Ra, 52La and sub-air'? 51Rb, 31Lb
, 52Rb, and 52Lb to increase the spring constant of the air spring, and the shock absorber 5
The control rods 20 of 1RC, 51LC, 52Rc, and 82LC are rotated to increase the damping force. In subsequent step] 70, a process of resetting the recovery time timer T1 and starting time measurement is performed, and the process returns to step 100.

On the other hand, in steps 155 to 160, if the currently detected imaging cycle is shorter or longer than the unsprung co-imaging determination cycle, the vehicle is in an unsprung co-pregnant state where the vibrations of the vehicle have a specific cycle. It is determined that this is not the case, and the process proceeds to step 175. Here, processing is performed to set the suspension characteristics to a soft state (SOFT), and the suspension characteristics are set to a soft state (SOFT).
Return to 00.

Next, a case will be described in which it is determined in step 105 that the rear wheel has run over the vehicle. The processing in this case is almost the same as steps 105 to 175 described above, so the corresponding processing is expressed with the same number as the last two digits. First, step 31 detects the minimum value of the latest rear wheel height data HR.
0), then it is determined whether the vibration of the vehicle is a single impact state or a continuous imaging state (step 315). If it is determined that the vehicle is in a single impact state, the suspension characteristic is changed to a soft state (SOFT), and then the process returns to step 100 (step 320). On the other hand, if it is determined that the vehicle is in a continuous vibration state, the boarding/lowering detection time timer T3 is started to measure time (step 325), and as time elapses, it is detected that the rear wheel shifts to the boarding/lowering state (step 330). 335). If the boarding/disembarking state is not detected within the detection reference time TB, step 1 above is performed.
Return to 00.

On the other hand, when it is detected that the rear wheel has shifted to the lowering state, the maximum value of the latest rear wheel vehicle height data HR is detected (step 340), and the count value of the lowering detection time timer T3 is determined to be unsprung. It is determined whether or not the minimum half period for determination is TC or more, and the maximum half period for determination of the unsprung mass is less than or equal to TO (step 355.360). If it is determined, the suspension characteristics are changed to the hard state (HARD), the recovery time timer T1 starts counting, and the process returns to step 100 (steps 365, 370>). If it is determined that
00 (step 375).

Above) As shown above, step 165 or step 3
After the suspension characteristics are changed to the hard state (HARD>) in step 65, if the process returns to step 100, the latest rear wheel height data HR must be set to the rear wheel width determination reference value Ho.
If the following occurs, that is, if the photographing of the vehicle is suppressed by changing the suspension characteristics, step 400 is performed.
Proceed to.

Here, it is determined whether the counted value of the return time timer T1, which started measuring time in step '170 or 370 described above, has become equal to or greater than the return reference time TA. If the time measurement is still insufficient and the return reference time A has not yet elapsed, the process returns to step 100. On the other hand, if the latest rear wheel height data HR does not exceed the rear wheel amplitude determination reference value HO and the return reference time TA has elapsed, the vehicle cannot be photographed because the suspension characteristics have been changed to the hard state (HARD). is determined to have been sufficiently attenuated, and the process proceeds to step 405. Here, the suspension characteristics are set to the soft state (SOF
T) is performed, and the process returns to step 100 above. Thereafter, this process is repeatedly executed when the vehicle is in a steady running state and the automatic mode (AUTO) is selected.

Next, an example of the control timing of the suspension control will be explained based on the timing chart of FIG. 9.

The time when the wheel rides down into the concave part of the road surface and the rear wheel height data HR exceeds the rear wheel amplitude determination reference value HO is tl. Detection of the maximum value of the rear wheel height data HR starts from time t1, and the maximum value is detected at time t2. For this reason,
At the same time t2, the run-over detection time timer T2 starts counting. Also, at this time t2, the front wheel vehicle height data H
It is detected that the absolute value of F also exceeds the front wheel amplitude determination reference value H1, confirming that the vehicle is in a continuous imaging state.

At time t2, detection of the rear wheel running over state due to rolling starts, and the rear wheel height data HR is set at time t3.
takes a small value exceeding the rear wheel amplitude determination reference value HO from the standard vehicle height position. At the same time t3, detection of the minimum value of the single multi-wheeled vehicle height data HR is started, and the minimum value is detected at time t4.

The time from time t2 when the maximum value of the rear wheel vehicle height data HR is detected to time t4 when the minimum value is detected is measured by a run-up detection time timer T2, and the measured value is the minimum half of the unsprung resonance judgment. If it is determined that the cycle is equal to or greater than the period TC and is less than or equal to the maximum half cycle TD for unsprung co-photography determination, the vehicle is considered to be in a state of unsprung co-photography in which the approximate number of motions is in the range of 10 to 15 [H7]. It will be judged. Therefore, at the same time t4, a process to change the suspension characteristics from the soft state (SOFT) to the hard state (HARD) is started, and at time t5, after the actuator drive time Ta has elapsed, the suspension characteristics are switched to the hard state (HA RD). . Also, from the above time t4, the return time timer T1
The timing starts.

The rear wheel height data HR begins to approach the standard vehicle height position after time t4, and the absolute value of the rear wheel height data 1-IH becomes smaller than the rear wheel amplitude determination reference value HO at time t6. At time t5, the suspension characteristics are in a hard state (HAR
D), the unsprung co-photographing state quickly converges, and the absolute value of the rear wheel height data HR becomes a value within the rear wheel amplitude determination reference value HO. Therefore, the count value of the return time timer T1, which started counting from time t4, exceeds the return reference time TA at time t7. Therefore, at the same time t
At 7, it is determined that the unsprung resonance state has converged, and the process of changing the suspension characteristics from the hard state (HARD) to the soft state (SOFT) is started, and at time t8 after the actuator drive time 1'-a has elapsed. The suspension characteristics are switched to a soft state (SOFT). Thereafter, if the absolute value of the rear wheel height data 1-Ht is greater than or equal to the rear wheel amplitude determination reference value HO and the vehicle is continuously vibrating, the change in the rear wheel height data HR is determined as described above. The suspension characteristics Processing is performed to change the state to the hard state (HARD). Note that if the absolute value of the rear wheel height data HR is greater than or equal to the rear wheel amplitude judgment reference value HO and the vehicle is in a state where a single impact has been applied, the suspension characteristics are changed to a soft state (SOFT), although not shown. ) is performed.

In addition, in this embodiment, the front wheel height sensor H1L,
1R, rear wheel height sensor H2C and ECU4 function as vehicle height detection means M1, and air suspension S1L, S1R
, S2L, S2R and suspension characteristic changing actuators A1L, AlR.

A2L and A2R correspond to the suspension characteristic changing means M2. Further, the process executed by the ECU 4 and the ECU 4 (steps 100, 115, 315> is the vehicle height determination means M3, and the process executed by the ECtJ4 and the ECU 4 (steps 125, 155, 160,
325, 355° 360) as the period determination means M4,
The ECU 4 and the processing executed by the ECU 4 (steps 165 and 365) each function as a control means M5.

As explained above, in this embodiment, when a vehicle height displacement is detected in which the rear wheel vehicle height data HR is equal to or higher than the rear wheel amplitude judgment reference value HO, it is determined whether the vehicle height displacement is due to a single impact or continuous vibration. If the impact is caused by a single impact, the suspension characteristics are changed to a soft state (SOF).
T), and on the other hand, when the vibration is due to continuous imaging, the half period of the vibration is equal to or greater than the minimum half period TC for unsprung resonance determination, and the maximum half period T for unsprung co-imaging determination
If it is below D, it is determined that the vehicle is in the unsprung state, and the suspension characteristics are changed to the bird state (HAR).
D). Therefore, it is possible to promptly and reliably detect an unsprung co-photographing state having a specific period (equivalent to 10 to 15 [H2] in terms of frequency) and converge the unsprung co-photographing state. As a result, the ground contact of the tires is improved, and the vehicle's maneuverability and stability can be maintained at a high level. This is particularly effective in preventing the rear wheels from skidding when the vehicle turns.

In addition, when a single impact is applied to the vehicle, or when imaging is based on both engine imaging and road impact, the suspension characteristics are set to a soft state (S
OFT), the above-mentioned impact or imaging is absorbed and ride comfort is improved.

Roughly speaking, the vehicle's imaging state is determined based on rear wheel height data HH, which indicates the height displacement of the rear wheels, which has a large impact on the ride comfort of rear seat passengers, and changes in suspension characteristics are controlled. Therefore, it is possible to promptly suppress imaging having a period of unsprung resonance that is uncomfortable for the occupant, thereby improving ride comfort.

In addition, under normal driving conditions, the suspension characteristics are set to a soft state (SOFT) that emphasizes ride comfort, and when an unsprung resonance state that repeats at a specific cycle occurs, the suspension characteristics are set to a bird state (HARD). Since the unsprung co-photographing state is converged quickly, there is also the advantage of increasing the degree of freedom when designing the suspension because there is no restriction on setting the suspension characteristics to prioritize one of the above two. .

□In addition, in this example, the suspension characteristics are set to soft 1 state (SOFT>) and bird state (+-(A RD>2).
The air suspension S1 is controlled by changing the stage.
By combining and changing various characteristics such as the spring constant of the air springs of R, S1L, S2R, and S2L, the damping force of the shock absorber, and the rigidity of the suspension bushings and stabilizer, it is possible to create a sports state that is intermediate between the above two stages. It is possible to early suppress the unsprung resonance state by changing to three stages including the state (SPORT) or roughly to multiple stages.

Next, other examples of suspension characteristic changing means other than air suspensions will be given.

First, as a first example, as shown in FIGS. 10(a) and 10(b), suspension characteristics are improved by having a mechanism for changing the rigidity of the bushings used in the connecting parts of rod-shaped suspension members such as the upper control arm and lower control arm of the suspension. This shows the configuration that can change the . Changing the rigidity means changing the spring constant and damping force in the bushing.

FIG. 10(a) is a vertical cross-sectional view showing the connecting portion of the rod-shaped suspension member, and FIG. 10(b) is a line B-- in FIG. 10(a).
8 is a sectional view according to FIG. In these figures, reference numeral 901 designates a control arm extending along axis 902 and defining hollow hole 903a. One end of the control arm 901 has an axis 904 perpendicular to the axis 902 and has a hole 90
A sleeve 906 having a diameter of 5 is fixed around the hole 905 by welding. An outer cylinder 908 having a hole 907 is fixed within the sleeve 906 by press fitting. An inner cylinder 909 is disposed within the outer cylinder 908 concentrically with the outer cylinder, and a bushing 910 made of anti-vibration rubber is interposed between the outer cylinder 908 and the inner cylinder 909. The bushing 910 cooperates with the outer cylinder 908 to define cavities 911 and 912 extending in an arc shape around the axis 904 at mutually opposing positions along the axis 902. The stiffness is set to a relatively low value.

The hollow hole 903 of the control arm 901 has an axis 902
It constitutes a cylinder that supports the piston member 913 so as to be able to reciprocate along the piston member 913. Piston member 913 and hollow hole 9
A seal member 914 is used to seal between the wall surface 03 and the wall surface 03. A contact plate 916 that is curved around the axis 904 and extends along the axis 904 is fixed to one end of the piston member 913 so as to closely contact the inner wall surface 915 of the cavity 911 .

The other end of the control arm 901 also has the same structure as shown in FIGS. A cylinder chamber 917 is defined between the piston member and the piston member, which is not shown in the figures. The cylinder chamber 917 is communicated with the outside through a screw hole 918 provided in the control arm 901. Screw hole 9
18 is screwed with a nipple 923 fixed to the other end 922 of a conduit 921 whose one end (not shown) is connected to a hydraulic pressure generation source, so that hydraulic pressure is supplied to the cylinder chamber 917. It is configured.

When the pressure of the oil in the cylinder chamber 917 is relatively low, the force pushing the piston member 913 to the left in the figure is also small, and the piston member 913 has a contact plate 916 that presses against the bush 91.
The bushing 910 is held at the illustrated position in light contact with the inner wall surface 915 of the bushing 910, so that the stiffness of the bushing 910 in the direction along the axis 902 is relatively low. On the other hand, cylinder chamber 9
If the hydraulic pressure inside 17 is relatively high, the piston member 913
is driven to the left in the figure, and the contact plate 916
Press the inner wall surface 915 of the bushing 910 and press the inner wall surface 915 of the bush 910.
16 and the inner cylinder 909 is compressed and deformed,
The stiffness of bushing 910 along axis 902 is increased.

Since the above-mentioned rod-shaped suspension member is provided between the wheels and the vehicle body, the suspension characteristics can be changed by controlling the hydraulic pressure in the cylinder chamber 917 (with a hydraulic pressure source and an actuator such as a hydraulic pressure control valve). This is done by controlling. In other words, when the hydraulic pressure increases according to instructions from the ECU 4, the stiffness of the bushing 910 increases, and the suspension characteristics increase the damping force and spring constant, making the suspension characteristics hard, improving maneuverability and stability. can be improved, and conversely, if the fluid pressure is lowered,
Shock can be reduced.

Next, as a second example, FIGS. 11(A) and 11(B) show other configurations of bushings having similar effects.

FIG. 11(a) is a longitudinal sectional view showing a bushing integrally constructed with an inner cylinder and an outer cylinder as a bushing assembly;
FIG. 1(b) is a sectional view taken along line CC in FIG. 11(a).

Embedded inside the bushing 1005 are four telescopic hollow bags 1010 extending along the axis 1003 at equally spaced positions around the axis 1003. Four chamber spaces 1011 are defined extending along an axis 1003 evenly spaced around the . Each hollow bag body 1010 has a cap 1012 embedded in the bush 1005 at one end thereof.
It is fixed at one end with a clamp 1013, and each chamber space 1011 is communicated with the outside of the bushing 1005 through a base 1012. One end of a hose 1015 is connected and fixed to the other end of the mouthpiece 1012 by a clamp 1014. Although the other end of each hose 1015 is not shown in the figure, it is communicatively connected to a compressed air supply source via an actuator such as a pressure control valve, thereby making it possible to introduce controlled air pressure into each chamber space 1011. It looks like this.

When the actuator is operated by the ECU 4, the air pressure within each chamber space 1011 can be varied, thereby making it possible to change the stiffness of the bushing steplessly. In this way, the stiffness of the bushing can be changed as appropriate after a change in vehicle height at the front wheels is detected.

Next, FIGS. 12A to 12G show the configuration of a stabilizer as a third example.

Fig. 12 (a) is a perspective view showing a torsion bar set stabilizer incorporated in an axle-type rear suspension of an automobile, and Fig. 12 (b) and Fig. 12 (c) are respectively
FIG. 12(d) is an enlarged partial vertical cross-sectional view showing the main parts of the example shown in FIG. 2(a) in an unconnected state and a connected state, respectively; FIG.
12(B) and 12(C) are perspective views with the clutch removed, and FIG. 12(E) is a perspective view of the main parts shown in FIG. 12(D). FIG.

In these figures, reference numeral 1101 indicates an axle housing that rotatably supports an axle 1103 connected to a wheel 1102. A pair of brackets 1104 and 11o5 are fixed to the axle housing 1101 at positions spaced apart in the vehicle width direction. A set of stabilizers 1106 is coupled to axle housing 1101.

The stabilizer 1106 consists of a stabilizer light 1107 disposed on the right side of the vehicle and a stabilizer left 1108 disposed on the left side of the vehicle, and the stabilizer light 1107 and the stabilizer left 1108 are selectively integrated with each other by a coupling device 1109. It is designed to be connected. Rod portions 1110 and 1112
End portions 1114 and 1115 shown in FIG. 12(b) opposite to the arm portions 1111 and 1113, respectively, have a protrusion 1117 and a hole 1118 extending along the axis 1116.
is formed. These protrusions and holes are provided with male and female threads that are screwed together, respectively, so that the rod portions 1110 and 1112 are aligned with the axis 1116.
are connected to each other for relative rotation around the . Returning to FIG. 12(a) again, arm parts 1111 and 1113
are connected to brackets 1123 and 1124 fixed to side frames 1121 and 1122 of the vehicle by links 1119 and 1120, respectively.

As shown in FIG. 12(c), the coupling device 11o9 includes a cylindrical clutch 1125 and one end 11 of a rod portion 1110.
14 and supports the clutch 1125 so that it cannot relatively rotate around the axis 1116 and can reciprocate along the axis 1116; and the rod part 1112.
A clutch 1125 is provided at the end 111 of the axis 11
Clutch receiver 1 is relatively unrotatably received around 16
127. It is a DD sectional view of FIG. 12(b). As shown in FIG. 12(f), the inner circumferential surface of the clutch 1125 has planes 1128 and 1129 facing each other on both sides of the axis 1116 and extending parallel to the axis 1116, and these planes as an axis. Cylindrical surfaces 1130 and 113 connect to 1116 at mutually opposing positions
1 and more. Correspondingly, the outer peripheral surface of the clutch guide 1126 has planes 1132 and 1133 facing each other on both sides of the axis 1116 and extending parallel to the axis 1116, and positions of these planes facing each other with respect to the axis 1116. Cylindrical surfaces 1134 and 113 connected at
5 and more. Similarly, as shown in FIGS. 12(d) and (e), the outer peripheral surface of the clutch receiver 1127 has flat surfaces 1136 and 1137 that face each other on both sides of the axis 1116 and extend parallel to the axis 1116, and It consists of cylindrical surfaces 1138 and 1139 connecting the planes at positions opposite to each other with respect to the axis 1116.

As shown in FIG.
129 and 1128 are always engaged, and the clutch 11
When 25 is in the position shown in FIG. 12(c),
Planes 1136 and 1137 of clutch receiver 1127
also planes 1129 and 112 of clutch 1125, respectively.
8, whereby the stabilizer right 1107 and the stabilizer left 1108 are integrally connected around the axis 1116 so that they cannot rotate relative to each other.

Especially the clutch receiver 11 as shown in FIG.
The ends of the flat surfaces 1136 and 1137 of No. 27 on the stabilizer light 1107 side are chamfered 1140 and 1141, so that the rod portions 1110 and 111
2 are slightly rotated relative to each other around the axis 1116, the clutch 1125 is rotated as shown in FIG.
The stabilizer right 1107 and the stabilizer left 1108 can be moved from the position shown in FIG. 12(c) to the position shown in FIG. They are integrally connected to each other in this state.

The clutch 1125 is reciprocated along an axis 1116 by an actuator 1142 controlled by the ECU 4. As shown in FIG. 12(A), the actuator 1142 is a hydraulic piston-cylinder device 1143 fixed to a differential casing (not shown), and is a sectional view taken along E-E in FIG. 12(B). As shown in FIG. 12 (G), the clutch 1
The 12th
A shift fork 114 connected to a piston rod 1148 of a piston-cylinder device 1143 shown in FIG.
9 and more.

When the actuator 1142 brings the clutch 1125 to the position shown in FIG. 12(C) according to the instruction from the ECLI 4, the stabilizer right 1107 and the stabilizer left 1108 are integrally connected, and the stabilizer 1106 starts its mechanism. By bringing the vehicle into a state where it can exert its full potential, rolling can be reduced and maneuverability and stability can be improved. or,
When the actuator 1142 brings the clutch 1125 to the position shown in FIG.
16 so that they can rotate relative to each other, thereby reducing the shock of the vehicle, especially the shock to only one wheel, and improving ride comfort.

Next, FIGS. 13A and 13B show another example of a stabilizer as a fourth example.

The stabilizer bar complete assembly 1310 of this example includes a first stabilizer bar 1318 as shown in FIG.
and a second stabilizer bar 1320. The first stabilizer bar has a main body part 1322 and an arm part 1323.
It has

The main body part] 322 is attached to the vehicle body by a pair of fittings 1324 so that it can be twisted around its axis.

As shown in FIG. 13(B), the second stabilizer bar 1320 is formed in a hollow shape and passes through the main body portion 1322 of the first stabilizer bar 1318. This second stabilizer bar 1320 is disposed inside a pair of fittings 1324, and can connect and disconnect the first stabilizer bar 1318. In the illustrated example, the spool 13
A piston 1330 to which a seal member 133 is fixed is attached to one end of the second stabilizer bar 1320.
2, it is slidably arranged in a liquid-tight state. This spool 1328 is made liquid-tight by a seal member 1334 and protrudes outward from the second stabilizer bar 1320.

The spool 1328 has a spline 1336 adjacent the piston 1330 while the second stabilizer bar 1
320 has a spline 1338 at one end that can engage spline 1336. The spool 1328 further includes a spline 134 on the inside of the outwardly projecting end.
has 0.

In the main body part 1322 of the first stabilizer bar 1318,
Coupler 134 coupled by spline 1342
4 is left out. The coupler 1344 has a spline 1340 at the end opposite the spool 1328.
It has interlockable splines 1346. In the illustrated example, the coupler 1344 is coupled to the mounting bracket 1324 via a rubber bushing 1345;
By deforming 345, the main body portion 1322 is configured to be torsionally deformed. coupler 1344
The attachment position is such that spline 1340 can engage spline 1346 when spool 1328 moves to the left and spline 1336 engages spline 1338. two splines 1340
, 1346 from dust.
347 is the second stabilizer bar 1320 and coupler 1
344.

The screws (~133) of the second stabilizer bar 1320
Two ports 1348.
135Q is provided, and piping is provided so that pressure fluid can be introduced to each port, and the port is put into use.

Now, when pressure fluid is introduced into the port 1350 through an actuator such as a hydraulic control valve, the piston 1330 moves to the left together with the spool 1328, and the spline 1336
is engaged with spline 133B, and spline 1340 is engaged with spline 1346, respectively. As a result, the first
and the second stabilizer bar 1318, 1320 are in a connected state, and the stiffness of the stabilizer bar assembly is increased.

Conversely, when pressure fluid is introduced into port 1348, piston 13
30 moves to the right, each spline is disengaged, and the stiffness of the stabilizer bar assembly is only that of the first stabilizer bar 1318.

Next, FIGS. 14(a) to 14(c) show an example of a black stabilizer as a fifth example.

The stabilizer 1410 of this example is shown in a schematic plan view in FIG. 14(a). Here, 1411 is a wheel, and 1412 is a suspension arm. It includes a main body 1414, a pair of arms 1416, and an extension means 1418.

The round bar-shaped main body 1414 passes through bearing portions 1421 of a pair of links 1420 arranged at intervals in the width direction of the vehicle body, and is supported by the bearing portions 1421 so as to be able to twist around its axis. . Another bearing 1422 at the upper end of the link 1420 is rotatably supported by a pin 1428 passed through a bracket 1426 welded to the vehicle body 1424. As a result, the main body 141
4 is arranged in the width direction of the vehicle body and can be twisted relative to the vehicle body.

In the illustrated example, the pair of arms 1416 is formed by a flat bar, and a first end 1430 thereof is connected to the body 1414.
is connected at both ends by bolts and nuts 1432 for rotation about a vertical axis. second end 1
431 is arranged at a distance from this end portion 1430 in the longitudinal direction of the vehicle body. Here, the front-back direction includes a diagonal case.

Extension means 1418 extends from second end 143 of arm 1416.
1 in the width direction of the vehicle body. In the illustrated example, the extension means 1418 is constituted by a power cylinder.

As shown in FIG. 14(c), the power cylinder includes a cylinder 1434, a piston 1436 slidably disposed in the cylinder 1434 in a liquid-tight manner, and one end connected to the piston 1436 and the other end connected to the cylinder 1434. A piston rod 1438 that protrudes to the outside, and a piston 1
436 in the direction in which the piston rod 1438 contracts. The piston 1436 is prevented from being biased beyond a predetermined level by a stopper 1442 fixed to the piston.

The cylinder 1434 is fixed to the suspension arm 1412 so that the piston rod 1438 is positioned outward in the width direction of the vehicle body.

A second end 1431 of the arm 1416 is connected to an outwardly projecting end 1439 of the piston rod 1438 by a bolt and nut 1432 so as to be rotatable about a vertical axis.

A flexible hose 1446 is connected to the liquid chamber 1444 on the opposite side of the cylinder 1434 from where the compression spring 1440 is located.
is connected at one end. This flexible hose 14
The other end of 46 is connected to a hydraulic pressure source (not shown) via an actuator such as a hydraulic control valve.

Depending on the state of the actuator according to the instructions from the ECU4,
If no pressure is supplied to the liquid chamber 1444 of the power cylinder, the wheel rate of the stabilizer will be low because the second end 1431 of the arm 1416 is located inward as shown in FIG. 14(a). .

On the other hand, the actuator operates according to the command from ECU4,
When pressure is supplied to the liquid W1444 of the power cylinder,
Pressure is applied to the piston 1436 and the piston rod 1438 is pushed out against the compression spring 1440, so the second end 1431 of the arm 1416 is pushed outward as shown by the two-dot chain line in FIG. 14(A). As a result, the arm ratio of the stabilizer increases, and the rigidity against rolling increases.

Next, as a sixth example, FIGS. 15(a) and 15(b) show the configuration of a coupling device between the stabilizer and the lower control arm.

FIG. 15(a) is a partial front view showing a wishbone type suspension incorporating the vehicle stabilizer coupling device according to this example, and FIG. 15(b) is a partial front view of the coupling device shown in FIG. 15(a). FIG. In these figures, 1501 indicates a wheel rotatably supported by a knuckle 1503. The knuckles 1503 are each pivotally connected at an upper end to one end of an upper control arm 1507 by a pivot 1505, and each at a lower end is pivotally connected to one end of an upper control arm 1507 by a pivot 1509.
It is pivoted to one end of 11. Upper control arm 1507 and lower control arm 1511 are pivotally connected to a cross member 1517 of the vehicle by pivots 1513 and 1515, respectively.

Further, in FIG. 15(A), reference numeral 1518 indicates a U-shaped stabilizer arranged in the vehicle width direction. The stabilizer 1518 is connected to the bracket 152 through a rubber bushing (not shown) at its central rod portion 1519.
2 to the vehicle body 1524 so as to be rotatable about its axis.

Tip 152 of arm portion 1520 of stabilizer 1518
0a are each connected to a position close to one end of the lower control arm 1511 by a connecting device 1525 according to this example.

As shown in detail in FIG. 15(b), the connecting device 1
525 includes a cylinder piston device 1526. The cylinder-piston arrangement 1526 consists of a piston 1529 and a cylinder 1530, which cooperate with each other to define two cylinder chambers 1527 and 1528. The cylinder 1530 includes an inner cylinder 1532 that receives a piston 1529 so as to be able to reciprocate along an axis 1531;
An outer cylinder 1533 arranged substantially concentrically with respect to the inner cylinder 1532, and an end cylinder V-shaped member 1534 that closes both ends of the inner cylinder and the outer cylinder.
and 1535. The piston 1529 includes a main body 1536 and a piston rod 1537 that supports the main body 1536 at one end and extends along the axis 1531 through the end cap member 1534 and a hole 1538 provided in the tip 1520a of the arm portion 1520 of the stabilizer 1518. It is becoming more and more.

A rubber bush 1540 and a retainer 1541 that holds the rubber bush 1540 are interposed between a shoulder 1539 formed on the piston rod 1537 and the tip 1520a, and a nut 1542 screwed into the tip of the piston rod 1537 is inserted.
A rubber bush 1543 and a retainer 1544 are interposed between the tip 1520a and the tip 1520a.
520 and is buffer-coupled to the tip 1520a.

The end cap member 1535 has a lower controller I/low/L.
A rod 1546 extending along the axis 1531 is fixed through a hole 1549tfim formed in the /7-mm 1511. A rubber bush 1547 and a retainer 1548 for holding the rubber bush 1547 are interposed between the end key V-shaped member 1535 and the lower control arm 15]1.
A rubber bush 1550 and a retainer 1551 for holding this are interposed between a nut 1549 screwed into the tip of the rod 1546 and the lower control arm 1511, so that the rod 1546 is connected to the lower control arm 1511 in a buffered manner. ing.

The inner cylinder 1532 has through holes 15 at positions close to the end cap members 1534 and 1535, respectively.
52 and 1553 are provided. The end cap member 1534 has a protrusion 1554 that extends along the axis 1531 between the inner cylinder 1532 and the outer cylinder 1533 and comes into close contact with the inner cylinder and the outer cylinder.
are integrally formed. The protrusion 1554 has one end aligned with the through hole 1552 and the other end aligned with the inner cylinder 153.
An annular space 1555 between 2 and the outer cylinder 1533
An internal passageway 1556 is formed that opens to. Thus, the through hole 1552, the internal passage 1556, the annular space 155
5 and the through hole 1553 define passage means for interconnecting the two cylinder chambers 1527 and 1528. Note that air is filled in a part of the annular space 1555, oil is filled in the cylinder chamber 1527, the internal passage 1556, and a part of the annular space 1555, and the piston 1529 is moved relative to the cylinder 1530. The change in volume within the cylinder of the piston rod 1537 caused by the displacement is compensated for by compression and expansion of the air sealed in the annular space 1555.

Communication of the internal passage 1556 is selectively controlled by a normally open electromagnetic on-off valve 1557. The electromagnetic on-off valve 1557 has a solenoid 1558 inside and a housing 1559 fixed to the outer cylinder 1533 at one end.
A core 1561 is disposed within a housing 1559 so as to be able to reciprocate along an axis 1560, and a compression coil spring 1562 biases the core to the right as viewed in FIG. 15(b). At one end of the core 1561 is a valve element 156.
3 is integrally formed, and the valve element 1563 has a hole 1 formed in the protrusion 1554 across the internal passageway 1556.
564.

In this way, when the solenoid 1558 is not energized according to the instruction from the ECU 4, the core 1561 is biased to the right in the figure by the compression coil spring 1562, and the valve is opened as shown in the figure to open the internal passage 1556. On the other hand, according to the instructions of ECtJ4, solenoid 155
8 is energized, the core 1561 is driven to the left in FIG. It is designed to cut off communication.

In the coupling device configured as described above, when the solenoid 1558 of the electromagnetic on-off valve 1557 is energized, the electromagnetic on-off valve is closed.
Communication between 1527 and 1528 is cut off, preventing oil in the two cylinder chambers from flowing into each other via internal passages 1556, etc., thereby preventing piston 1529
is prevented from displacing relative to the cylinder 1530 along the axis 1531, whereby the stabilizer 1
518 is brought into a state where it can perform its original functions, the rolling of the vehicle is suppressed and the vehicle rides on one wheel.
The maneuverability and stability of the vehicle when getting on and off are improved.

Further, if the solenoid 1558 is not energized, the electromagnetic on-off valve 1557 is maintained in the open state as shown in FIG.
Since the oil in the cylinders 1528 and 1528 freely flow through the internal passages 1556 and the like, the pistons 1529 can freely move relative to the cylinders 1530, and as a result, both the left and right arm portions of the stabilizer 1518 The tips of the corresponding lower control arms 1
Since the stabilizer can move freely relative to 511, the stabilizer does not perform its function, thereby reducing wheel shock and ensuring sufficient riding comfort.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and it goes without saying that it can be implemented in various forms without departing from the gist of the present invention. Ru.

Advantages of the Invention As detailed above, the suspension control device of the present invention is such that the vehicle height determining means determines that the vehicle height detected by the vehicle height detecting means exceeds a predetermined value, and the period of change in the vehicle height is determined by the vehicle height determining means. When the period determining means determines that the period is within a predetermined range including the period at the time of unsprung resonance, the control means is configured to output a command to change the suspension characteristics to a harder state to the suspension characteristics changing means. For this reason, an excellent effect is achieved in that it is possible to promptly detect imaging having a period close to the period at the time of unsprung resonance, and to suppress the imaging.

In addition, as mentioned above, the suspension characteristics are stiffened based on the imaging cycle to converge the vibrations, which improves the tire's ground contact and improves maneuverability and stability when driving on rough roads. .

Furthermore, in the event of a single impact, the suspension characteristics will be switched to emphasize ride comfort, while improving maneuverability and stability in the event of a cycle close to that of unsprung co-pregnancy as described above. It is possible to realize so-called semi-active control of the suspension by switching to the resuspension characteristic.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram conceptually illustrating the contents of the present invention, Fig. 2 is a system configuration diagram showing a suspension control device that is an embodiment of the present invention, and Fig. 3 is a diagram used in this embodiment. A sectional view of the main parts of the air suspension, Figure 4 is the 3rd
5 is a block diagram for explaining the configuration of the electronic control unit (ECU), FIG. 6 is a block diagram showing a digital vehicle height sensor signal input circuit, and FIG. A block diagram showing an analog vehicle height sensor signal input circuit, Figure 8 is a flowchart of the processing executed by the electronic control unit (ECU), and Figure 9 shows the front wheel height displacement, rear wheel height displacement, and suspension characteristics. Timing charts showing changes over time, FIGS. 10 to 15 show examples of other devices that change suspension characteristics;
Figure 0 (a) is a longitudinal sectional view of the first example, Figure 10 (b) is a BB sectional view thereof, Figure 11 (a) is a sectional view of the second example, and Figure 11 (b) is a sectional view of the second example.
Figure 1 (b) is the C-C cross-sectional view, and Figure 12 (a) is the third
FIG. 12(B) and (C) are respectively enlarged partial longitudinal sectional views of the third example, FIG. 12(D) is a perspective view of the main part, and FIG. 12(E) is the same. Figure (D) is a plan view, Figure 12 (F) is a DD cross-sectional view in Figure 12 (B),
Figure 12 (g) is a sectional view taken along E-E, and Figure 13 (a) is the 4th cross-sectional view.
FIG. 13(b) is a partially enlarged longitudinal cross-sectional view of the same figure (a), FIG.
Figure (B) is a partial explanatory view of Figure (A), Figure 14 (C) is a sectional view of the extension means, Figure 15 (A) is a partial front view showing the state of use of the sixth example, and Figure 15. (B) is an enlarged cross-sectional view of the coupling device shown in FIG. Ml...Vehicle height detection means M2...Suspension characteristic changing means M3...Vehicle height determination means M4...Cycle determination means M5...Control means S1R, Sl L, S2R, S2L...Air suspension HlR, Hll...Front wheel height sensor H2C...Rear wheel height sensor

Claims (1)

[Scope of Claims] 1. Vehicle height detection means for detecting the distance between the wheels and the vehicle body as a vehicle height; Suspension characteristic changing means for changing suspension characteristics in response to an external command; Detection by the vehicle height detection means. vehicle height determining means for determining whether the vehicle height exceeds a predetermined value; and whether a period of change in vehicle height detected by the vehicle height detecting means is within a predetermined range including a period at the time of unsprung resonance. a cycle determining means for determining whether or not the vehicle height has exceeded a predetermined value; a suspension control device comprising: control means for outputting a command for changing suspension characteristics to a harder state to the suspension characteristics changing means;