JPS59102610A - Air-spring type suspension apparatus - Google Patents

Abstract

PURPOSE:To improve driving feeling by throttling each electromagnetic throttle valve of an air spring and a buffer so that a chassis roll becomes a prescribed value or less on driving on a curved road and perfectly opening the both electromagnetic throttle valves on driving on a straight road. CONSTITUTION:The detected value of a car-height sensor 15 for detecting a chassis roll, air pressure 14 of an air spring body 7, set pressure 21 of a spring body 7, set value 22 of car-height, number 23 of revolutions of engine, car speed 24, and the amount 25 of operation of a brake pedal are input into a microcomputer 20. The amount of chassis roll is calculated on the basis of the signal supplied from the car-height sensor 15 which is input on driving on a curved road, and when the roll over a prescribed value is generated, the solenoid valve 8 of an air spring 5 and the solenoid valve 4 of a shock absorber 1 are throttled, and each damping force is increased. When the roll value reduces below a standard value, the solenoid valves 4 and 8 are opened perfectly, and the shielding effect of the minute roll accompanied with the variation of road surface is increased. With such a constitution, suspension in accordance with the magnitude of the roll is permitted, and driving feeling is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air spring suspension system for a vehicle.

When a vehicle travels on an oil road, centrifugal force causes the vehicle body to tilt toward the outside of the oil road. Additionally, if a wheel on one side falls into a deep pothole, this will cause the vehicle body to shake (roll) significantly from side to side.

An air spring suspension system can block the roll of the vehicle body against slight vibrations caused by small irregularities on the road surface, but it can prevent the rolling of the vehicle body from slight vibrations caused by small irregularities on the road surface, but it can prevent the roll of the vehicle body from rolling, albeit slowly, when the wheels fall into large potholes or when driving on an oil road. It is difficult to quickly attenuate this for a large amount of light. For this reason, the roll is absorbed by a shock absorber, but the damping characteristics of the shock absorber increase as the displacement speed (frequency) increases, but when the displacement speed is slow, it is difficult to dampen the roll quickly. However, there is a problem in that a phenomenon called seasickness occurs.

In view of the above-mentioned problems, an object of the present invention is to throttle the electromagnetic throttle valve of the air spring when the roll of the vehicle body becomes larger than a predetermined value when driving on an oil road, etc., and at the same time throttle the electromagnetic throttle valve of the shock absorber. The valves are throttled to increase the damping force to increase the roll rigidity of the suspension system, and when driving on a straight road, both of the electromagnetic throttle valves mentioned above are fully opened to increase the effect of blocking minute rolls due to changes in the road surface, and to constantly An object of the present invention is to provide an air spring type suspension device which provides good riding comfort.

Therefore, in an air spring type suspension system in which an air spring and a shock absorber are arranged between a vehicle body and each wheel, the configuration of the present invention is such that an air spring is disposed in a passage connecting an air spring main body of the air spring and an air tank. A first electromagnetic throttle valve provided in the vehicle body, a second electromagnetic throttle valve provided in the middle of a throttle passage connecting the liquid chambers at both ends of the shock absorber, a roll reference signal setting device that generates a roll reference signal, and a vehicle body. a sensor for detecting a tilting driving state; and a signal from the sensor and a signal from the roll reference signal setter. a control device that drives a second electromagnetic throttle valve, and when the output signal of the arithmetic circuit is larger than the signal of the roll reference signal setter, the first. The second throttle valve is throttled, and when the output signal of the arithmetic circuit is smaller than the signal of the roll reference signal setter, the first throttle valve. The second electromagnetic throttle valve has all zero openings.

The present invention will be explained based on one embodiment. As shown in the overall configuration in FIG. 1, detection signals hL and hR from vehicle height sensors 15 provided on the left and right wheels, respectively, as sensors for detecting a driving state in which the vehicle body is tilted, are applied to an arithmetic circuit 32. The difference Δ11 between the two is found, it, IJgl]
added to device 33. On the other hand, roll reference signal setting device 3
The reference value Δbo set by 1 is applied to the control device 33, and the output signal Δh of the arithmetic circuit 32 becomes the reference value Δ11.
If it is larger than 0, the air spring electromagnetic throttle valve 8 will be described later.
and configured to throttle the passage of the electromagnetic throttle valve 4 of the shock absorber.

More specifically, the left and right front wheel suspensions A and the left and right rear wheel suspensions B shown in FIG. 2 are constructed in exactly the same way. That is, between the known control arm that supports each wheel and the vehicle body, there is a cylinder 2 and an F
A shock absorber 1 consisting of a piston 3 equipped with an
A is the condor lure! are combined into two. Liquid chambers at both ends of the cylinder 2 partitioned by a piston 3 are connected via an electromagnetic throttle valve 4 .

There is also an air spring 5 between the vehicle body and the controller (roll arm).
is supported. In this air spring 5, a tank 6 and a vertically expandable spring body 7 formed of a diaphragm or a bellows are connected through an electromagnetic throttle valve 8. The tank 6 is connected to a pneumatic tank 13 or to the atmosphere via a conduit 9 and a vehicle height adjustment valve C consisting of an intake valve 10 and an exhaust valve 26. In other words, by energizing the Tsureno C drive 10a, the intake valve 10
When listening to
When the exhaust valve 26 is opened by opening the exhaust valve 26, the air in the air spring body 7 is released to the atmosphere, and the vehicle height is lowered.

In the case of the rear wheel suspension system B, the tanks 6 of the left and right air springs 5 are connected to the air pressure tank 13a or the atmosphere via separate vehicle height adjustment valves C, but this is different from that of the front wheels. This is because the height of the left and right rear wheels varies greatly depending on the state of the cargo, so the vehicle height of the left and right wheels can be adjusted separately.

In addition, before operating the front wheel brake 17, the air pressure tank 19 is connected to the brake valve 27. It is connected to the front wheel brake 17 via a pressure reducing valve 28 and a relay valve 18. Similarly, the pneumatic tank 19 is connected to the rear wheel brake 17a via a brake valve 27, a pressure reducing valve 28 and a sushi well 18.

In order to detect the vehicle height of each wheel, a vehicle height sensor 15 is disposed between the spring body 7 and an appropriate part on the axle such as the tank 6, and this detection signal is sent to a digital signal via an AD converter. and added to the C microcomputer 20. In order to detect the vehicle body load applied to each wheel, an air pressure sensor 14 is provided to detect the air pressure inside the spring body 7, and this detection signal is applied to the microcomputer 20 as a digital signal via an AD converter.

Further, the microcomputer 20 includes an air pressure setting device 21 that includes a potentiometer for setting a reference value of the air pressure of the spring body 7 and a switch for generating a reference value setting signal, and a vehicle height setting device 21 that includes a potentiometer and a switch for generating a reference value setting signal. The signals from the brake sensor 25, which detects the amount of operation of the brake pedal 22, engine speed sensor 23, heavy speed sensor 24, and brake pedal, are added as digital signals via an AD converter. When the reference value is changed, the microcomputer 20 adjusts the vehicle height adjustment valve C based on the signal from the vehicle height sensor 15 and the signal from the vehicle height setter 22.
is operated to adjust the amount of air in the air springs 5 for the front and rear wheels to maintain the vehicle height within a predetermined range from the reference value set by the vehicle height setting device 22. However, during normal driving, the vehicle height adjustment valve C does not operate.

As shown in FIG. 3, the air spring 5 has a small-diameter cylindrical portion 6a formed on the upper end side of the tank 6, and the lower end portion of a spring body 7 made of a bellows is connected to the upper end wall of the small diameter cylindrical portion 6a so as to surround the cylindrical portion 6a. Ru. A mounting plate 60 is coupled to the upper end of the spring body 7, and the above-mentioned air pressure sensor 14 is connected to this via a connecting pipe 61. As described above, the S pipe 9 is coupled to the tank 6 and connected to the pneumatic tank 13 via the vehicle height adjustment valve.

A cylindrical portion 69 protruding inward of the tank 6 is integrally formed on the upper wall of the air tank 6, and a solenoid 8a is coupled to surround the cylindrical portion 69. A stem 68 is guided and supported by the cylindrical portion 69, and a valve plate 62 for closing the upper ends of the six cylindrical portions is supported at the upper end of the stem 68. A spring 67 is interposed between the lower end of the cylindrical portion 69 and the valve plate 62. A throttle passage 63 is installed in the valve body 62, and the cylinder t56
The inside of the spring body 7 and the inside of the air chamber are communicated through two passages 65. Further, the valve body 62 is pushed down against the spring 67 in response to the current that excites the solenoid 8a, and the upper end of the tank 6 is opened to the throttle passage 7 between the valve body 62 and the valve body 62.
0 is narrowed down.

As shown in FIG. 4, the shock absorber 1 has a piston 3 fitted inside a cylinder 2 to partition chambers 47 and 50, and the piston 3 slides between a stopper 57 and a collar 58. It is now possible to do so. Then, the O-rad 3a coupled to the piston 3 is projected downward and coupled to the control arm of the suspension system. On the other hand, a floating piston 46 is fitted into the chamber 47, thereby forming a gas chamber 45 at the upper end of the cylinder 2. And piston 3
Floating screws 1 to 46 are adapted to slide up and down by the pressure in the gas chamber 45 in order to compensate for the excess or deficiency of the working fluid between 47 and 50 with respect to the vertical movement of . A rod 41 is coupled to the upper end of the cylinder 2 so as to be connected to the vehicle body.

A conduit 44 extending from the seedling 47 and a conduit 43 extending from the chamber 50
An electromagnetic throttle valve 4 is connected between the two. The electromagnetic throttle valve 4 is provided with an orifice 54 that communicates the conduits 44 and 43 inside the housing 52, and a valve body 55 that adjusts the passage area of the orifice 54 is pressed against the housing 52 by a spring 51.
53 is supported. Then, when the solenoid 4a is energized, the valve body 55 whose tip becomes tapered against the force +53 protrudes into the orifice 54 tl, thereby reducing the passage surface.

The vehicle height sensor 15, which serves as a means for detecting the roll of the vehicle body, is composed of a potentiometer, as shown in FIG.
72 with bolt 79, 1Pil! 7' is fixedly supported at 78. and bracket i'2
The air spring body 7 has poles 1 to 1 on the mounting plate 6o, which has a clay part on its surface.
The lower end of the link 75, in which the lower end of the link 72 passes through the horizontally extending guide piece 72a, is fixed to the wall of the tank 6 with a bolt 76. Then, the bottle 73 supported at the upper end of the link 75 is engaged with the elongated hole 74 of the arm 77. (Second I
:5, the relative displacement between the mounting plate 6o of the 1j bolt 4 and the tank 6 and the change in vehicle height is converted into a rotational movement of the arm 77, which is roughly converted into an electrical signal by the potentiometer 15. .

Next, the operation when the device of the present invention is controlled by a microcomputer will be explained. Fig. 7-8 is a flow chart of the above-mentioned control program and ram.
29 indicates each step of the flowchart. The calculation part is set to ρ11 by key operation of the engine. p12 detects the driving state in which the vehicle body leans (rolls) for each front and rear wheel, and controls the electromagnetic throttle valves 8 and 4 of the air spring and shock absorber accordingly. The input/output to be performed is selected, and in step p13, a roll subroutine to be described later is entered based on these input/output signals, and predetermined control is performed. Next, in p14, the input/output for the left and right rear wheels is selected, and in p15, the roll subroutine is entered in the same manner as described above, and predetermined control is performed.

As shown in Figure 8, the subroutine starts at p16,
At ρ17, the vehicle height hR from the unsprung portion to the sprung portion of the right wheel is detected. At 918, the vehicle height hL of the left wheel is detected. p
19, the difference in vehicle height between the right and left wheels Δh (-hn-h
Find L). At p20, it is determined whether the absolute value of the difference Δh in the III height is larger than the reference value Δho.

If the difference Δ11 in vehicle height between the left and right wheels is the reference value ΔhO(1
If it is larger than 5u (approx. Similarly, set the electromagnetic throttle valve 8 of the left wheel air spring on p.26, and p.27.
At 028, the electromagnetic throttle valve 4 of the shock absorber (denoted as SA) for the right wheel is throttled, and at 028, the electromagnetic throttle valve 4 of the left wheel shock absorber is throttled to increase the damping force of the air spring and the shock absorber.

In p20, the difference Δh in vehicle height between the left and right wheels is the reference value Δh.

If it is smaller than p21. Fully open the electromagnetic throttle valve 8 of the air spring for the right and left wheels on p22, and p23゜9.
At step 24, the electromagnetic throttle valves 4 of the shock absorbers of the right and left wheels are fully opened. 1) End at 29 and repeat the program with the next input/output. In addition, the electromagnetic throttle valve for each wheel8.4
The order of operations can be determined arbitrarily.

In the actual fI example shown in FIG. 9, a lateral acceleration sensor is used as a sensor for detecting a driving state in which the vehicle body is tilted < (which causes CI-roll). This lateral acceleration sensor uses, for example, a piezoelectric element, and can obtain a signal that has a different sign in the left and right directions and is proportional to the magnitude of acceleration. In FIG. 9, the calculation part is set to 1)31 by the engine key operation, lateral acceleration 9 is detected by the lateral acceleration sensor at p32, and the detected ff1g is set in advance on the program as the lateral acceleration standard (11- It is determined whether or not it is greater than go.

If the detected Via is larger than the reference value -oo, p3
Detected in 4! It is determined whether h is larger than the reference value child go. If the detected value is larger than the reference value + go, the electromagnetic throttle valve 8 of the air spring of the right front wheel is fully opened in p31, the Nto throttle valve 8 of the air spring of the left front wheel is fully opened in p38, and in 1139 Right rear wheel air spring electromagnetic throttle valve 8
is fully opened, and the left rear wheel air spring electromagnetic throttle valve 8 is fully opened at I)40. Similarly, in p41 to p44, Him throttle valve 4 of the shock absorber of the right/left front wheel and the right/left rear wheel.
are all questions.

If the detected value 9 is smaller than the reference ft1-ao in p33, the sign of the detected value is changed to -9 in p35. p36
The difference C' between the detected value g and the reference value go is determined. and,
In p45 to p48, the opening degrees of the electromagnetic throttle valves 8 of the air springs of the right and left front wheels and the right and left rear wheels are throttled in proportion to the difference 9' between the detected value and the reference value. Furthermore, on p49-p52, the right
The electromagnetic throttle valves 4 of the shock absorbers of the left front wheel and the right and left rear wheels are throttled in proportion to the difference Q' between the detected value and the reference value.

If the detected value g is larger than the reference value + go in p34,
In the same way as above, in 936, find the difference O between the detected value and the reference value,
At p45 to p52, the air spring electromagnetic throttle valve 8 and the shock absorber 'IIi magnetic throttle valve 4 are throttled in proportion to the differential low. Note that the relationship between the detected value of the lateral acceleration and the throttle amount of the electromagnetic throttle valve 4.8 is as shown in FIG. Therefore, the damping force of the air pump and the shock absorber increases in accordance with the magnitude of the lateral acceleration caused by turning the vehicle, increasing the roll rigidity of the suspension system and suppressing the roll of the vehicle body.

In the control program shown in Fig. 11, a potentiometer shaft is disposed in the longitudinal direction of the vehicle body, and a pendulum that swings left and right is attached to this shaft as a sensor for detecting the driving state in which the vehicle body tilts (rolls). The roll of the vehicle body is detected by a potentiometer, and this detection signal is used to control the electromagnetic throttle valve 8 of the air spring and shock absorber.
4. In the case of this pendulum hole potentiometer, as shown in Fig. 12, when there is no left or right inclination, the sensor output is VO, and the sensor output corresponding to the reference value 10 go of rightward lateral acceleration is VH1 leftward. The output of the sensor corresponding to the lateral acceleration a-go is set as VL, and when the detected value of the sensor exceeds this reference value VH+VL, the electromagnetic comparison valves 8 and 4 are controlled.

As shown in Figure 11, when the engine starts, p61
Then, in p62, the detected value ■ of the lateral acceleration sensor is read. In p63, it is determined whether the detected value ■ is smaller than the reference value VL, and if the detected value ■ is smaller than the reference value VL,
In p64, find the difference V' between the reference value VL and the detected value ■, and in 967 to p74 throttle the electromagnetic throttle valves 8 of the air springs of the right and left front wheels and the right and left rear wheels in proportion to this difference v'. Further to the right
Electric shock absorber for left front wheel and right/left rear wheel! !
Tighten the comparison valve 4.

If the detected value V is larger than the reference value VL in p63,
At p65, it is determined whether the detected mv is larger than the reference value VH. If the detected value ■ is larger than the reference value VH, the difference V- between the two is determined in p66, and the electromagnetic throttle valve of the air spring and shock absorber is adjusted in proportion to the difference V' in p67 to p74 as in the previous case. 8. Narrow down to 4. In this way, by throttling the air springs of each wheel and the electromagnetic throttle valve of the shock absorber, the damping force is increased, the roll rigidity of the suspension system is increased, and the roll of the vehicle body is suppressed.

Further, if the detected value ■ is smaller than the reference value VH at p65, the air spring of each wheel and the electromagnetic throttle valve 8.4 of the shock absorber are fully opened at p75 to p82.

The control program shown in FIG. 13 uses a steering angle sensor and a vehicle speed sensor as sensors for detecting the driving state in which the vehicle body tilts (rolls), and based on these signals, controls the electromagnetic throttle valve 8 of the air spring and the shock absorber. This is to control the electromagnetic throttle valve 4. Since the zero angle of the vehicle body is proportional to the steering angle θ of the vehicle and the square of the vehicle speed, the throttle amount of the electromagnetic throttle valve is increased in proportion to the steering angle θ, as shown in FIG. As shown in the figure, the throttle amount φ of the electromagnetic throttle valve is controlled in proportion to the square of the vehicle speed S.

In FIG. 13, the sieve portion is set to 991 when the engine is started. Vehicle speed S is detected in p92, 1)93
The steering angle θ is detected at step 94, and the aperture amount φ is determined at step 94 based on these detection signals. Next, in step 1) 95, the reference value φ0 set in advance on the program is compressed.

That is, when the detected value φ is larger than the reference value φ0, the difference φ' between the two is determined in 99B, and in proportion to this difference φ', the electromagnetic force of the air springs of the front, rear, right, and left wheels is The throttle valve 8 is throttled, and in p101 to p104, the electromagnetic throttle valve 4 of the front, rear, right, and left small wheel shock absorbers is throttled, the damping force of the air spring and the shock absorber is increased, the roll rigidity of the suspension system is increased, and the roll of the vehicle body is reduced. suppress quickly.

If the detected value φ is smaller than the reference value φ0 in p95,
At p105 to p108, the electromagnetic throttle valves 8 of the front, rear, right, and left air springs are fully opened, and at p109 to p112, the electromagnetic throttle valves 4 of the shock absorbers of the front, rear, right, and left wheels are fully opened. This program is repeated in sequence.

In each of the embodiments described above, the passage of the electromagnetic throttle valve 8.4 is narrowed when energized, but conversely, when energized, the electromagnetic throttle valve 8.4 is fully open, and when not energized, the electromagnetic throttle valve 8.4 is closed. .4 may be narrowed down.

As mentioned above, when the detection signal of the sensor that detects the driving state in which the vehicle body is tilted exceeds the reference value that requires roll control, this Komei throttles the air spring's N exit valve +13 and the shock absorber's electromagnetic throttle valve. As a result, the damping force of the air spring and shock absorber is increased, and the roll rigidity of the suspension system is increased, so when a roll with large shaking occurs, the roll is quickly suppressed. To reduce the unpleasant seasickness phenomenon caused by a vehicle equipped with a suspension system. When each electromagnetic throttle valve is throttled, an air spring, due to its characteristics, can obtain a relatively large damping force at a low displacement speed (the speed at which the fluid passes through the electromagnetic throttle valve), while a shock absorber can obtain a relatively large damping force at a high displacement speed (the speed at which the fluid passes through the electromagnetic throttle valve). Since a large damping force can be obtained at the speed at which the air passes through the electromagnetic throttle valve, the synergistic effect of the air spring and the shock absorber produces an optimal damping effect not only according to the size of the roll but also the speed of the roll. is obtained. Additionally, when the body roll is small, the normal air springs and shock absorbers function to maintain the soft, quiet ride characteristic of vehicles equipped with air spring suspension systems.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a schematic configuration of an air spring suspension system according to the present invention, Fig. 2 is an overall configuration diagram of the same device, Fig. 3 is a front sectional view of the air spring, and Fig. 4 is a shock absorber. 5 is a side view showing how the vehicle height sensor is installed, FIG. 6 is a front view of the same, and FIGS. 7 and 8 are the first implementation of the software for controlling the air spring suspension system. 9 is a flowchart illustrating a second embodiment of the software for controlling an air spring suspension AT, and FIG. 10 is a flowchart illustrating the detected value of lateral acceleration in the same device and the throttle of the electromagnetic throttle valve. Figure 11 is a flowchart explaining the third embodiment of Rough 1 to Wear for controlling an air spring suspension system, and Figure 12 is a diagram showing the characteristics of the sensor used in the system. FIG. 13 is a flowchart illustrating a fourth embodiment of the software for controlling an air spring suspension system, and FIGS. 14 and 15 are lines representing characteristics of sensors used in the same system. It is a diagram. A: Front wheel suspension system B: Rear wheel suspension system C: Vehicle height adjustment valve 1: Shock absorber 2 cylinder 3: Piston 4: Electromagnetic throttle valve 5: Air spring 6: Tank 7: Spring body 8: Electromagnetic throttle (1→ - 13: Pneumatic tank 15
: Vehicle height sensor 20: Microcomputer 22: Vehicle height setting device 31: Reference signal setting device 32: Arithmetic circuit 3
3: Control device patent applicant I'1JS Jidosha Co., Ltd. Agent Patent attorney Toshio Yamamoto 18 Figure 9 Figure 10 ROLL III Figure 11 ← Nine spoons → Draw fLL (9) 75 Fuji 12 Figure 82 ρl”1lLf17 14Figure 15Figure

Claims (1)

[Claims] In an air spring type suspension system in which an air spring and a shock absorber are arranged between a vehicle body and each wheel, a first electromagnetic throttle is arranged in a passage connecting an air spring body of the air spring and an air tank. a second electromagnetic throttle valve disposed in the middle of a throttle passage connecting liquid air at both ends of the shock absorber; and a roll reference signal setting device for generating a roll reference signal;
a sensor that detects a driving state in which the vehicle body is tilted; and a signal from the sensor and a signal from the roll reference signal setter. and a control device that drives a second electromagnetic throttle valve, and when the output signal of the arithmetic circuit is larger than the signal of the roll reference signal @ setter, the first. The second throttle valve is throttled, and when the output signal of the arithmetic circuit is smaller than the signal of the roll reference signal setter, the first throttle valve. An air spring suspension system characterized in that a second electromagnetic throttle valve is fully opened.