JPS6025810A - Hydro-pneumatic suspension - Google Patents

Abstract

PURPOSE:To control a rolling angle within a predetermined range and to make the most of soft comfortable ride by an air spring, by closing solenoid valves in turn by an electronic controller in relation to turning run. CONSTITUTION:A hydro-pneumatic suspension 1 possesses a liquid chamber 9 and an air chamber 11 to be divided by a piston 8 and a diaphragm 3 provided on a cylinder 7 slidably, and a rod 10 connected with the piston 8 is connected with a control arm 13. To adjust a spring constant by changing capacity of the air chamber 11, a first air tank 2, a second air tank 2a and a third air tank 2b further are connected through a solenoid valves 14, 15, 16 in series with the air chamber 11 respectively. The solenoid valves 14, 15, 16 are opened or closed through an output signal of an electronic controller 30 making a signal of a load 18 into an input.

Description

DETAILED DESCRIPTION OF THE INVENTION Akira Mizumoto has a subject related to hydropneumatic suspension systems for vehicles.

Hydropneumatic suspension systems provide a good ride comfort due to the softness of the air springs, but on the other hand, when turning, the vehicle body is affected by the O-moment h generated in the vehicle body, causing the vehicle body to tilt significantly, resulting in poor handling stability. There is a problem of loss.

Conventionally, as shown in Japanese Patent Laid-Open No. 51-C30320, for example, the lateral acceleration and longitudinal acceleration acting on the vehicle body are detected, and the spring constant of the air spring is changed based on this detection signal. However, the electronically controlled device for obtaining the optimum spring constant that matches the detection groove of the acceleration sensor is far from perfect.

The purpose of the present invention is to provide a hydropneumatic system that can increase the roll stiffness commensurate with the car body load during cornering, suppress the roll angle within a predetermined range, and make use of the soft riding comfort of air springs during normal driving. The purpose of the present invention is to provide a suspension system.

For this reason, the configuration of the present invention is a hydropneumatic suspension system in which the liquid chamber of an air spring, which is divided into an air chamber and a liquid chamber by a diaphragm, is communicated with the liquid chamber of a hydraulic cylinder unit mounted on the vehicle body. Smell 10: The air spring is equipped with a plurality of air tanks that are connected to the liquid chamber in series through electromagnetic shut-off valves, and an electronic control device causes the N magnetic valve to close in relation to the turning movement of the vehicle. This allows them to be closed one after another.

To explain the present invention based on an embodiment, as shown in FIG.
The piston 8 and diaphragm 3 are slidably mounted on the piston 8 and the diaphragm 3.
The piston 8 has a liquid chamber 9 and an air chamber 11 partitioned by a piston 8 and a control rod 10 connected to a control 7-m 13. This control arm 1
3 is swingably supported on a support shaft 28 with respect to the vehicle body 20 at its base end, and supports a wheel 6 at its distal end via a known knuckle. The liquid chamber 9 is connected to a hydraulic pressure adjustment device N19 through a conduit 21, and from the hydraulic pressure in the conduit 21, a load sensor 18 detects the vehicle body load carried by each wheel.

In order to adjust the spring constant by changing the volume of the air chamber 11, a first air tank 2 is connected to the air chamber 11 via an electromagnetic on-off valve 14, and a second air tank 2 is connected to the air chamber 11 via an electromagnetic on-off valve 15.
A is further connected in series with a third air tank 2b via an electromagnetic on-off valve 16. The electromagnetic on-off valves 14, 15 and 16 are configured to be opened and closed by output signals from an electronic control unit 30 which receives signals from the load sensor 18 as input.

Although only the suspension system for the front wheels of the vehicle body is shown in FIG. 1, the suspension system for the rear wheels is also constructed in the same way, and a common electronic control unit 30 controls the electric vAl? l Valve closed 14.15.
16 are eliminated. As shown in FIG. 2, the electronic control unit 30 is composed of a microprocessor 32, a memory 33, and an interface 31. A signal corresponding to the vehicle body load carried by each wheel, which is detected by the load sensor 18 of each of the front and rear wheel suspensions 1, is input to the interface 31 as a digital signal by the ΔD converter 34. Also,
A signal from a turning angle sensor 37 that detects the turning angle of the handle 36 is sent to the interface 31 as a digital signal by an AD converter 38.

In the ROM of the memory 33, lines 42 and 41 are respectively shown in FIG.
As shown in 14, the roll stiffness at straight-travel vehicle (j) that can withstand the vehicle body load carried by each wheel and the roll stiffness required during cornering are stored as a control map.
As shown by a line 43 in the figure, the roll stiffness R (see FIG. 3) to be controlled in the swing seat 1j with respect to the vehicle body weight vJ handled by each wheel is stored as a 1lJtil map. (Then, from the above-mentioned control map, appropriate wheel stiffness 11 is determined based on the signal from internal sensor 18 corresponding to the vehicle body load carried by each wheel, and electromagnetic on-off valves 14, 15. 16
One or? ! It is configured to open several pieces. In other words, when the car body load is the minimum (empty car), the electromagnetic on-off valve 16 is closed, when it is medium, the electromagnetic on-off valve 15 is closed, and when it is the maximum, the on-off valve 14 is closed, and the spring constant of the air spring is determined. Increase roll rigidity with a comb.

FIG. 5 shows a flowchart of the control 10-gram described above.

In the same figure, CD11 to p23 indicate each step of the flowchart. At the same time as the e engine is started, the engine part is plld, and p1
2 opens the electromagnetic on-off valve 14, p13 opens the electromagnetic on-off valve 15, and +1111 opens the electric 1 on-off valve 16 to maintain the soft ride quality of the air spring during normal driving.

At p15, it is determined whether the turning angle of the steering wheel is 20 degrees or more. If the steering wheel turning angle is less than a predetermined value, for example 20 degrees, the process returns to p12. In addition, if the steering wheel turning angle is 206 or more in p15, it is determined in p16 whether the weight of the vehicle body Vi shared by the front, rear, left, and right wheels of T is the minimum (empty vehicle), and if the heavy body load is the minimum, in p17 Close the electromagnetic on-off valve 14 and return to 1) 15.

On the other hand, if +110 indicates that the intermediate load vi of each wheel is not the minimum, it is determined in p18 whether the vehicle body load of each wheel is moderate. If the vehicle body load carried by each wheel is moderate, close the N magnetic on-off valve 14 in p19,
At p20, close the electromagnetic on-off valve 15 and return to p15.

In addition, if the vehicle body load carried by each wheel exceeds a medium level at +118, the electromagnetic on-off valve 14 is closed at p21, the electromagnetic on-off valve 15 is closed at p22, the electromagnetic on-off valve 16 is closed at p23, and +115 Return to In this way, the steering angle of the handle is detected at predetermined intervals, and the roll rigidity is determined according to the steering angle of the handle.

As described above, even when turning on the same road, the roll angle changes depending on load conditions such as changes in the number of occupants on the vehicle body. Since it closes the spring constant of each wheel and changes the spring constant of each wheel, tilting of the vehicle body is suppressed and stable maneuverability can be achieved. The spring constant of the air spring can be reduced to provide a comfortable ride.

In the above-mentioned embodiment, the steering angle is detected and the stiffness of the steering wheel is controlled based on the detected +14I angle, but the roll stiffness is controlled based on the difference between the vehicle speed and the steering angle. By increasing the stiffness, it is possible to eliminate the time lag in control of steering wheel operation.

[Brief explanation of the drawing]

Figure 1 shows the Hyde Nikomachik Suspension S according to the present invention.
+: [I] Figure 2 is a block diagram showing the schematic configuration of the device, and Figures 3 and 4 show the control map stored in the memory of the electronic control unit of the device. FIG. 5 is a flowchart of a program that controls the device. 1: D'jFjHM 2.2a, 2b: Air tank 7: Cylinder 8: Piston 13: 21 Control rod 14.15, 16:? Iim on/off valve 18
: Mukaiju Senri 19: Hydraulic pressure adjustment device 30:? ff control device 37: Cutting angle

Claims (3)

[Claims] (1) A hydropneumatic suspension system in which the air chamber and the liquid chamber (the liquid chamber of the air spring divided into two parts) are connected to the liquid chamber of one hydraulic cylinder attached to the vehicle body through a diaphragm, The air spring includes a plurality of air tanks connected to the liquid chamber in series through one magnetic closing valve, and the electromagnetic opening/closing valve is controlled by an electronic control device in relation to the turning movement of the vehicle. C!lfi A hydropneumatic suspension system configured to be closed next. (2) A load sensor is disposed on each of the front and rear, left and right suspension systems, and the electromagnetic on-off valve is controlled by the output signal of the electronic control device based on the signal from the load sensor. ) The hydropneumatic suspension system described in ). (3) Claim (1) in which the electromagnetic +'liJ valve closing is controlled by an output signal of the electronic control I device based on signals from a medium speed sensor and a steering angle sensor.
Hydropneumatic suspension system as described in.