JPS59106308A - Air spring type suspension - Google Patents

Abstract

PURPOSE:To check the occurrence of a dive promptly as well as to prevent a car attitude from yielding, by throttling both solenoid throttle valves for an air spring and a shock absorber when the output of a sensor, which detects such a driving state as causing a car body to dive, goes beyond the reference value. CONSTITUTION:As a sensor as detecting such a driving state as causing a car body to largely tilt over, each of car-level sensors 15 is installed in both front and rear wheels, while detecting signals hF and hR out of each car-level sensor 15 are impressed on an operation circuit 32. At the operation circuit 32, a difference h between both signals is found, then the differential signal given is added to a control circuit 33 and hereat compared with a reference value DELTAho set by a dive reference signal setter 31. And, in time of being DELTAh>DELTAho, each of solenoid throttle valves 4 and 8 is throttled while in time of being DELTAh<DELTAho, they are controlled so as to fully open both these valves 4 and 8. The solenoid throttle valve 8 is installed in a passage interposingly between a spring body 7 of an air spring 5 and an air tank 6 while the solenoid throttle valve 4 is installed in a passage interposingly between both end liquid chambers of a shock absorber (unillustrated herein).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to air spring suspension systems for vehicles.

When a vehicle suddenly starts or brakes, a large inclination (diameter) occurs in the longitudinal direction of the vehicle. Air spring suspension systems have a low spring constant and can block dirt, but when the vehicle suddenly accelerates or brakes suddenly, the vehicle body tilts significantly in the front and rear directions, and there is a risk that the vehicle's posture will collapse, causing passengers to fall, especially in buses. be.

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 a single diamond becomes larger than a predetermined value when the vehicle is running rapidly or suddenly braking, and at the same time throttle the electromagnetic throttle valve of the shock absorber. In addition to increasing the damping force and increasing the rigidity of the suspension system, when driving on a normal flat road, both of the electromagnetic throttle valves mentioned above are fully opened to reduce minute vibrations caused by changes in the road surface. To provide an 8-position air spring type suspension that enhances the blocking effect of the air and always provides good riding comfort.

For this reason, e. the structure of the invention is that in an air spring type suspension system in which an air spring and a shock absorber are arranged between the vehicle body and each Φ wheel, the air spring main body of the air spring and the air a first electromagnetic throttle valve disposed in a passage connecting the tank;
A second electromagnetic throttle valve disposed in the middle of a narrowing throttle passage that connects the liquid chambers at both ends of the shock absorber, a type early reference signal setting device that generates a dive reference signal, and a driving state in which the vehicle body is tilted forward or backward is detected. - a sensor, and the first
゜a control device for driving a second electromagnetic throttle valve, and when the output signal of the arithmetic circuit is larger than the signal of the type reference signal setter, the first. Squeeze the second throttle valve,
When the output signal of the arithmetic circuit is smaller than the signal of the dive base W; signal @ setter, the first. The second electromagnetic throttle valve is fully opened.

The present invention will be explained based on one embodiment. As the overall configuration is shown in Fig. 1, a vehicle height sensor 15 is installed on each of the front wheels and rear wheels as a sensor for detecting a driving state in which the vehicle body is tilted significantly forward or backward, and these detection signals are 11F
, h R are applied to the arithmetic circuit 32, where the difference Δh between the two is determined and added to the control device 33'f\. On the other hand, the reference value Δl+o set by the dive reference signal @ setter 31 is added to the control device 331, and the arithmetic circuit 3
When the output signal Δ11 of No. 2 is larger than the reference value Δ1)0, the passages of the air splash electromagnetic throttle valve 8 and the shock absorber electromagnetic throttle valve 4, which will be described later, are throttled.

More specifically, as shown in FIG. 2, the left and right front wheel suspension systems A and the left and right rear wheel suspension systems B are configured in exactly the same way. That is, a shock absorber 1 consisting of a cylinder 2 and a piston 3 fitted into the cylinder 2 is disposed between a known control arm that supports each wheel and the vehicle body. Rods 3a are respectively connected to the controller 1-roll arms. hiss 1~
The liquid chambers at both ends of the cylinder 2, which are separated by °C by a cylinder 3, are connected to each other by means of an electromagnetic throttle valve 4.

There is also air splash 5 between the vehicle body and control 1 roll arm.
is supported. This air spring 5 is connected to a tank 6 and a vertically expandable spring body 7 made of a diaphragm or bellows through an electromagnetic throttle valve 8. The tank 6 is connected to a pneumatic tank 13 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, the solenoid 10a is energized and the suction valve 10
When opened, the compressed air from the pneumatic tank 13 flows into the air spring body 7 by lJ[1λ, raising the vehicle height. air is released to the atmosphere, lowering the vehicle height.

In the case of the rear wheel suspension system 8, the tanks 6 of the left and right air springs B are connected to the air pressure tank 13a or the atmosphere via separate vehicle height adjustment valves C; This is because the vehicle height on the left side of the rear wheel varies greatly depending on the load condition, so the vehicle height on the left side is adjusted separately.

(b) In order to operate the front wheel brake 17, air 1
1-Tank 19 is connected to front wheel brake 17 via brake valve 27, pressure reducing valve 28 and relay valve 18. Similarly, the air pressure tank 19 is connected to the brake valve 27 and the pressure reducing valve 28.
and is connected to the rear wheel brake +78 via the relay valve 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. It will be added as a microconference on 20th evening. Pneumatic pressure sensor 1-14 detects the air pressure inside the spring body 7 in order to detect the vehicle body load applied to each wheel.
This detection signal is applied to the microcomputer 20 as a digital signal via an AD converter.

Furthermore, the microcomputer 20 includes a potentiometer for setting the reference value of the air pressure of the spring body 7, an air pressure setting device 21 consisting of a switch for generating a reference ship setting signal, and a vehicle height setting device 21 consisting of a potentiometer and a switch for generating a reference value setting signal. A setting device 22, an engine speed sensor 23, a vehicle speed sensor 24, and a brake sensor 25 which detects the operation amount of the brake pedal 13 are applied as digital signals via an AD converter.

19 width medium (this J4 high setting setter 2211 [l rotation:
Change the preparation 1. To! 5! Jj'2 is 71° clone r rl, -72'':'!(')'1.1 Shenchang 1
Based on the f word of z sled 1 ε] and the vehicle height 12 regulator 22 [j cloud, the J Uip height adjustment valve C is activated to reduce the air volume of the electric IJ 5 of the front and rear wheels. Then, set the vehicle height from the standard value set by the vehicle height setting device 22 (:).
The height adjustment valve C is closed during normal driving.
doesn't work.

!337
)<formation f fL 2/l) jl@on the wall・\+:1
-1-< to 1:E One end of the F main body 7 is the circle L
): Ib Q to surround a (two combinations of 41 ro).

At the lower end of the main body 7, there are connected Q, f (31a, z fH1-) and the above-mentioned hitting pressure sensor 14 is connected to this. A conduit is connected to tank 6, width high pitch! l! valve, C,, fp t.
, air! ■It is connected to the link 13 (Mamoe, -fushi, =do (-91)).

'7 Dunk C on the top wall of Nk 6 in EO! 5/The protruding FJ west part 09 is formed integrally and the solenoid 8a is connected to it so that it is recessed. A stem 68 is guided and supported by the cylindrical portion 69, and a valve plate 62 for closing the upper end of the cylindrical portion 69 is supported at the upper end of the stem 68. A spring 67 is placed between the lower ends of the six cylindrical parts and the valve plate 62.
is interposed. A passage 63 crosses the valve body 62, and communicates the inside of the spring body 7 with the inside of the tank 6 via a passage 65 of the cylindrical portion 69. Furthermore, the valve body 62 is pushed down against the spring 67 in response to the evening current that excites the solenoid 8a, and the throttle passage 70 between the upper end wall of the tank 6 and the valve body 62 is pushed down.
is narrowed down.

As shown in FIG. 4, the shock absorber 1 has a screw 3 fitted into the inside of the cylinder 2 to partition the chambers 47 and 50, and the piston 3 is inserted between the flange 57 and the flange 5.
It opens and moves 1q between it and B. Then, the rod 3a connected to the piston 3 is projected downward and connected to the roll arm at the suspension position i. on the other hand,
A floating screw 1-46 is fitted into the chamber 47, thereby forming a scrap 45 at the upper end of the cylinder 2. In order to compensate for the excess or deficiency of the working fluid between the chambers 47 and 50 with respect to the vertical movement of the screws 1-3, the floating piston 46 is caused to slide up and down by the pressure in the waste chamber 45. There is. A rod 41 is coupled to the upper end of the cylinder 2 so as to be connected to the vehicle body.

Conduit 44 extending from to 47 and conduit 43 extending from chamber 50
An electromagnetic throttle valve 4 is connected between the two. The electromagnetic throttle valve 4 has an A-refit 54 installed inside the housing 52 that communicates the conduits 44 and 43, and a valve body 55 that adjusts the passage area of the A-refit 54 is pressed against the housing 52 by a spring 51.
．． 53 is supported. Warp, -C, solenoid 4
When a is excited, a valve body 55 whose tip is tapered against the spring 53 is projected into the A refit 54, and is configured to reduce the passage surface f.

Vehicle height sensor 15 as a means of detecting mid-term holidays
As shown in Fig. 5.6, the 7 langes '15a, which are integral with the frame, are fixed to the bracket 1-72 with bolts 79, and are fixed to the shaft 78 by @7.
7 is fixedly supported. Then, the upper end of the bracket;
It is supported by On the other hand, the lower end of the link 75, which passes through a guide piece 728 extending horizontally from the lower end of the bracket 72, is fixed to the wall of the tank 6 with a bolt 76.

The bottle 73 supported on the upper end of the link 75 is attached to the arm 77.
is engaged with the elongated hole 74 of. In this way, the spring body 7
The relative displacement between the mounting plate 60 and the tank 6, that is, the change in vehicle height, is converted into a rotational movement of the arm 77, and further 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 is a flowchart of the above-mentioned control program, and p12 to p24 indicate each step of the flowchart. The calculation part is set to p12 by key operation of the engine. In p13, the vehicle is detected for each front wheel and rear wheel, and in order to control the corresponding electromagnetic throttle valve 8.4 of the air spring and shock absorber, the vehicle height tlFR of the right front wheel is detected by the vehicle height sensor 15. 9
14, the vehicle height hr:L of the left front wheel is detected. Detect p15'c right rear wheel vehicle height 1+pp, and plG detect fi left rear wheel vehicle height 11 degrees. p17 U also calculates the average type i of the front axle from the vehicle height hF of the front wheels and the vehicle height hFL of the front left width! Calculate % hF. 1) Find the average vehicle height IBI of the rear axle from the vehicle height hRR of the white rear wheel and the vehicle height hRL of the left rear wheel. plQ
Find the vehicle height difference △II of the CffJ rear axle, and calculate the ρ2Or difference Δ1
) is larger than a reference end ΔhO preset on the program.

The difference in vehicle height between the front and rear axles △h is based on △1 (15mm).
If the value is larger than (13), (25) the electromagnetic throttle valve 8 of the air spring (indicated by As) of the right front wheel is throttled.

Quantity: 1126 Shock absorber for right front wheel (S△
Compare the electromagnetic throttle valve 4 of the left front wheel at L127, the electromagnetic throttle nail 4 of the left front wheel shock absorber at page 28, and check the air splash. and increase the damping force of the shock absorber.

If the vehicle height difference Δh between the front and rear axles is smaller than the reference value ΔhO in p20, (S is 1) 21, the electromagnetic throttle valve 8 of the air spring of the right front wheel, and the electromagnetic throttle valve 8 of the right front wheel air spring in p22. Replace the throttle valve 4 with the N magnetic throttle valve 8 of the air spring on the left front wheel on page 23.
In p24, the electromagnetic throttle valve 4 of the shock absorber of the left front wheel is fully opened. This program is executed sequentially and repeatedly. Note that the order of operation of the electromagnetic throttle valves 8.4 for each wheel can be arbitrarily determined.

In the embodiment shown in FIG. 8.9, the signal of the vehicle speed sensor 24 is detected at predetermined time intervals, and the acceleration is determined from this curve.
When this acceleration exceeds a reference value, as shown in FIG. 9, the throttle amount β of the electromagnetic throttle valves 8 and 4 is controlled according to the magnitude of the acceleration α.

In Fig. 8, the operational part is set to p30 by the engine key operation, the vehicle speed is detected at predetermined time intervals by the vehicle speed sensor 24 at p31, and the time for the difference between the currently detected vehicle speed S1 and the previously detected vehicle speed δ2 is determined at p32. Interval T
Find the acceleration α from the quotient.

At p33, it is determined whether the detected acceleration value α is larger than an acceleration reference value −α0 set in advance on the program.

Based on the detection value α! If it is better than % bean-α0, p3
In step 4, it is determined whether the detected value α is larger than the reference value +αO. If the detected value α is smaller than the reference value + αO, the electromagnetic throttle valve 8 of the air spring of the right front wheel is fully opened in D37, and the electromagnetic throttle valve 8 of the air spring of the left front wheel is fully opened in D38.
Fully open, and on page 39, open the electromagnetic throttle valve 8 of the air spring for the right rear wheel.
Fully open, and at p40, open the electromagnetic throttle valve 8 of the left rear wheel air spring.
is fully opened. Similarly, in p41 to p44, the electromagnetic throttle valves 4 of the shock absorbers of the right and left front wheels and the right and left rear wheels are fully opened.

1) If the detected value α at step 33 is smaller than the reference value -αO, the sign of the detected value is changed to -α at step p35.

1) Find the difference β between the detected value α and the reference value α0 at 3G.

Then, in pages 45 to 04B, the air springs of the right and left front wheels and the right and left rear wheels are compared, and the opening degree of the valve 8 is reduced in proportion to the difference β between the detected value and the standard value. Furthermore, to p49/p52
The electromagnetic throttle valves 4 of the shock absorbers of the FG/left front wheel and the right/left rear wheels are throttled in proportion to the difference β between the detected value and the reference value.

Even if the detected value α is larger than the reference value + αO in p, '34, the difference β between the detected value and the reference value is calculated in 936 as described above and @, and the air spring electromagnetic throttle valve 8 is determined in p45 to I)52. And the electromagnetic throttle valve 4 of the shock absorber is throttled in proportion to the difference β. Therefore, the damping force of the air spring and the shock absorber increases in accordance with the magnitude of acceleration due to sudden start, sudden acceleration, and sudden braking of the vehicle, increasing the rigidity of the suspension system and suppressing the diameter of the vehicle body. This program is executed repeatedly in sequence.

In the actual flow example shown in FIG. 10, the brake sensor 25 is used as a sensor to detect the operating state in which the m-rest tilts back and forth (dive), and based on this brake pressure 1), the air spring electromagnetic throttle valve 8J3 and It controls the electromagnetic throttle valve 4 of the shock absorber. Since the diameter of the vehicle body is proportional to the brake pressure p, the throttle darkness of the electromagnetic throttle valves 8 and 4 is controlled in proportion to the brake pressure p, as shown in FIG.

In FIG. 10, when the engine is started, the operational part is set to p93. , p94, the play-1-pressure p is detected, and p95, it is compared with the IJ brake pressure standard Wipo, which is set in advance with the progera 11 soil. That is, detection IP
is greater than the reference 1i17po, then p9G'?
Find the difference p between the two, and calculate p97 in proportion to this difference p'.
~p100] Throttle the electromagnetic throttle valves 8 of the air springs of the rear right and left wheels, and throttle the electromagnetic throttle valves 4 of the shock absorbers of the front, rear, right, and left wheels in p101 to p104, thereby reducing the damping force of the air springs and shock absorbers. This increases the rigidity of the suspension system and prevents the car from diving into water.

When the detected lap is smaller than the reference value po in p95 (
In p105-p108, the electromagnetic throttle valves 8 of the left and right air springs after f1 are fully opened, and in p109-p112, the 'I4 magnetic throttle valves 9 4 of the shock absorbers of the front, rear, right, and left wheels are fully opened.

This program is executed sequentially and repeatedly.

In each of the embodiments described above, the passages of the electromagnetic throttle valves 8 and 71 are narrowed when energized, but conversely, when energized, the electromagnetic throttle valves 8 and 4 are fully open, and when not energized, the electromagnetic throttle valves are closed. 8.4
It may be configured such that the number of

Honkomei [, 1] As mentioned above, if the detection signal of the sensor that detects the driving condition that causes the vehicle body to tilt forward or backward (type) exceeds the reference value that requires dive control, the electromagnetic throttle valve of the air spring and the shock By throttling the electromagnetic throttle valve of the absorber, the damping force of the air spring and shock absorber is increased, and the rigidity of the suspension system is increased. Therefore, when a large vibration occurs, the vibration can be quickly suppressed. This reduces the amount of distortion in the body posture of a vehicle equipped with an air spring suspension system. When each electromagnetic throttle valve is throttled, an air spring can obtain a relatively large damping force at a low displacement speed (velocity of the fluid passing through the electromagnetic throttle valve) due to its characteristics, while a shock absorber can obtain a relatively large damping force at a high displacement speed (velocity of the fluid passing through the electromagnetic throttle valve). Since a large damping force can be obtained depending on the velocity of the fluid passing through the electromagnetic throttle valve, the synergistic effect of the air spring and shock absorber produces an optimal damping effect not only according to the size of the dive but also the speed of the die 1. can get. Furthermore, when the vibrations of the vehicle body are small, the normal air spring and shock absorber functions can maintain the soft and quiet ride characteristic of a vehicle equipped with an air spring suspension system.

[Brief Description of the Drawings] Fig. 1 is a block diagram showing the schematic structure of the air spring suspension system according to the present invention, Fig. 2 is an overall configuration diagram of the device, and Fig. 3 is a front sectional view of the air spring. , Fig. 4 is a front sectional view of the shock absorber, Fig. 5 is a side view showing the vehicle height folded state, Fig. 6 is a front view of the same, and Fig. 7 is a control of the air spring type suspension system. FIG. 8 is a flowchart illustrating a first embodiment of a sonotrope for controlling an air spring suspension system.
! Fig. 9 is a diagram showing the relationship between the vehicle acceleration and the throttle amount of the N9 throttle valve in the same device, and Fig. A flowchart explaining the third embodiment of the rough 1-ware for controlling the device, Figure 11 is a line representing the relationship between the brake pressure of the vehicle applied to the device and the throttle stone of the electromagnetic throttle valve. There is a diagram. △: Front wheel suspension system B: Rear wheel suspension system C: Vehicle height adjustment valve 1: Shock absorber 2 Niji cylinder 3: Pice 1-
4: Electromagnetic throttle valve 5: Air spring 6: Tank 7; Spring body 8: ? ! 1fl12 valve 13: Air pressure tank 15: Vehicle height sensor 20; Microcomputer 2
4: Vehicle speed sensor 25 Brake sensor 31: Reference signal setter 32: Derivative circuit 33: Control II device patent applicant Patent applicant Isusei Jidosha Co., Ltd. Patent attorney Toshio Yamamoto Figure 7 DIVE It is diagram IVEOI Figure 10

Claims (1)

[Claims] An air spring suspension system in which an air spring and a shock absorber are arranged between the vehicle body and each wheel - C1 A first air spring suspension system arranged in a passage connecting the air spring body and the air tank. The electromagnetic throttle valve, the second electromagnetic throttle valve disposed in the middle of the throttle passage connecting the liquid mass at both ends of the shock absorber, and the dive reference signal setting device that generates the dive reference signal, etc., cause the vehicle body to tilt forward or backward. A sensor detects the operating state, and the first. and a control device that drives the second electromagnetic throttle valve, and the output signal of the control circuit is controlled by the tie 7.
゛If the reference signal @ is larger than the signal of the setter, the first
, the second throttle valve is throttled, and when the output signal of the throttle circuit is smaller than the signal of the type standard setter, the first throttle valve is throttled. The air suspension system is characterized by the fact that the second electromagnetic throttle valve is fully opened.