JPH07237421A - Car height adjuster - Google Patents

Abstract

PURPOSE:To save labor by shortening the time required for adjustment of car level after stoppage of a vehicle. CONSTITUTION:In a car level adjuster, which has air springs 18 and 21 for adjusting the car level by the air from a pneumatic source 10 and attenuation variable type of hydraulic cylinders 19 and 20 each in a pair at front and rear wheels, a supply valve 16 is provided in a supply and exhaust passage 15 for air being sent from the pneumatic source 10 to the air springs 18 and 21 of each wheel. A key OFF sensor 34, which detects ignition switching from ON to OFF, car level sensors 32, at front and rear wheels, and G sensors 33 which detect the speed of the car body in up and down direction, at front wheel side, are provided. This is further provided with a control means which sets the hydraulic cylinders 19 and 20 to the so-called soft modes in case that the ON OFF of ignition is detected by the key OFF sensor 34 and that the adjustment of car level is necessary, and sets them to hard modes when the up/down speed of a vehicle gets to or comes close to zero after that.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle height adjusting device.

[0002]

2. Description of the Related Art In a vehicle height adjusting device, a hydraulic cylinder and an air spring are provided for each wheel of a vehicle, and air is supplied to and discharged from the air spring so as to respond to the running state of the vehicle or to the occupant. There is a vehicle that can obtain an optimum vehicle posture according to the number of passengers. For example, when air is supplied to the air spring from an air pressure source, the air spring expands, whereby the hydraulic cylinder is displaced in the extending direction and the vehicle height increases. Therefore, by utilizing this to supply the air to the air springs of the outer wheels at the time of cornering, it is possible to suppress the sinking of the outside of the vehicle and make the posture of the vehicle flat.

On the other hand, if the vehicle is stopped immediately after the cornering and the ignition key is turned off, the vehicle height outside the vehicle at the time of cornering becomes high, and a vehicle height difference occurs between the left and right sides of the vehicle. A supply valve communicates the inside of each air spring to eliminate the difference in vehicle height between the left and right sides (this similar structure is disclosed, for example, in Japanese Utility Model Laid-Open No. 4-62205).

[0004]

By the way, a damping force variable type capable of switching between a so-called soft mode in which importance is placed on riding comfort and a so-called hard mode in which importance is attached to maneuverability is used for the hydraulic cylinder. However, in a vehicle height adjusting device using such a hydraulic cylinder, for example, when the hydraulic cylinder is in the hard mode when the ignition key is turned off immediately after the cornering described above, the air spring Since the moving speed of the piston of the hydraulic cylinder that operates by supplying and exhausting air to and from the vehicle is low, the vehicle height adjustment time becomes long.

Therefore, since the opening time of the supply valve is set in accordance with the vehicle height adjusting time, there is a problem that the opening time of the supply valve becomes long, the power consumption increases, and the battery is burdened.

Therefore, the present invention provides a vehicle height adjusting device which consumes less power and can adjust the vehicle height promptly after the vehicle stops.

[0007]

A vehicle height adjusting mechanism 1 for adjusting a vehicle height for each wheel by supplying and discharging a working fluid from a pressure source, and a vibration input from a road surface via a suspension device. In a vehicle height adjusting device having a damping force variable mechanism 2 that damps and changes this damping force according to the running state of the vehicle, the supply and discharge passages of working fluid provided in each vehicle height adjusting mechanism communicate with each other. The valve means 3, the key-off detection means 4 for detecting that the ignition is turned off, the vehicle height detection means 5 for detecting the vehicle height, the vertical speed detection means 6 for detecting a change in the vehicle height, and the key off. The damping force of the damping force variable mechanism 2 is reduced based on the ignition OFF detection signal detected by the detection means 4, and then the vertical speed of the vehicle height detected by the vertical speed detection means 6 is 0 or 0. The control unit 7 to increase the damping force of the damping force varying mechanism 2 when approaching provided.

[0008]

For example, a case where the vehicle stops when the vehicle height on the right side of the vehicle is high and the vehicle height on the left side is low will be described as an example.

First, when it is detected by the key OFF detection means 4 that the ignition key is turned from ON to OFF, it is next determined based on a signal from the vehicle height detection means 5 whether vehicle height adjustment is necessary. To be done. When it is determined that the vehicle height adjustment is necessary, when the damping force of the damping force variable mechanism 2 is large, the valve means 3 communicates the supply and discharge passages and the damping force of the damping force variable mechanism 2 is small. Adjusted to.

As a result, the vehicle quickly becomes flat, and after passing through this, the posture changes to a position where the vehicle height on the right side of the vehicle is slightly lower and the vehicle height on the left side is slightly higher. Here, when the vertical speed detecting means 6 detects that the vertical speed on the right side or the left side of the vehicle is 0 or approaches 0, the damping force of the damping force variable mechanism 2 is adjusted to a large side, and soon the vehicle is Become flat.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a structural explanatory view showing an embodiment of the present invention. In the figure, 10 indicates an air pressure source as a pressure source, and this air pressure source 10 has a compressor 11, a motor 12, a switching valve 13, a dryer 14, and the like.
Supply and discharge passages 15 connected to the compressor 11 are arranged on the front side and the rear side of the vehicle, respectively, and are divided into left and right sides, and a supply valve 1 as valve means arranged corresponding to each wheel.
Connected to 6. The supply valve 16 opens and closes the supply / discharge passage 15 by an output signal of the control means 17.

The air spring 18 is provided on the front wheel side.
A hydraulic cylinder 19 (damping force varying mechanism) having an integrated (vehicle height adjusting mechanism) is connected to the supply valve 16, and is provided separately from the hydraulic cylinder 20 (damping force varying mechanism) on the rear wheel side. An air spring 21 (vehicle height adjusting mechanism) is connected to the supply valve 16.

Both the hydraulic cylinders 19 and 20 are of a damping force variable type which can be switched between so-called hard mode and soft mode, and this switching is performed by the control means 17 or by switching operation.

Here, the structure of the hydraulic cylinder will be briefly described with reference to FIG. 3 by taking the hydraulic cylinder 19 in which the air spring 18 is integrated as an example.

In the figure, reference numeral 22 denotes a cylinder, and the lower end of the cylinder 22 is attached to a wheel. A piston 23 is provided in the cylinder 22, and an upper end of a piston rod 24 of the piston 23 is attached to the vehicle body. A rolling guide 25 is joined to the outer periphery of the cylinder 22, and a diaphragm 28 that forms an air chamber 27 between the rolling guide 25 and the outer shell 26 on the vehicle body side is provided at the peripheral edge of the rolling guide 25. The diaphragm 28 is a main constituent element. The air spring 18 is configured as. Here, the air chamber 27 communicates with the supply / discharge passage 15. In addition, 29 is an insulator rubber and 30 is a bumper rubber.

A step motor 31 is provided at the upper end of the piston rod 24. The step motor 31 rotates the control rod 32 in the piston rod 24 to open and close an orifice (not shown) to switch between a hard mode and a soft mode. The damping force can be adjusted.

Therefore, for example, when air is supplied from the air pressure source 10 to the air chamber 27 through the supply / discharge passage 15, the diaphragm 28 expands, which causes the piston rod 24.
The vehicle height is adjusted by increasing the vehicle height.

Although the hydraulic cylinder 20 and the air spring 21 are separate bodies on the rear wheel side, their description is omitted because they have known structures. Here, the hydraulic cylinder 20 is also a variable damping force type and is connected to the control means 17 in the same manner as the front wheel side.

The control means 17 includes a vehicle height sensor 32 as a vehicle height detecting means for each wheel, and a vertical speed detection for detecting a sprung speed or a left and right relative speed of portions corresponding to the left and right front wheels. G sensor 33 as means,
Key OF as a key OFF detection means for detecting the ignition switch from ON to OFF
The F sensor 34 is connected to each.

Next, the operation will be described with reference to the flow chart shown in FIG. 4 and the time chart shown in FIG.

When the vehicle running is stopped and the ignition key is turned off (step 1 to step 2), for example, there is a difference in vehicle height because the right side of the vehicle is high and the left side of the vehicle is low, and it is necessary to adjust the vehicle height. If so (step 4), and only if the hydraulic cylinders 19, 20 are in hard mode (step 5), the hydraulic cylinders 19, 2
0 is switched from hard mode to soft mode (step 6).

Incidentally, the hydraulic cylinder 19.20 when the vehicle is stopped.
Is in the soft mode, the process of step 7 described later is performed. Further, when the ignition key remains ON in step 2, for example, when the vehicle is traveling, normal vehicle height control is performed (step 3). Further, if there is no large imbalance in the vehicle height in step 4 and it is not necessary to adjust the vehicle height, the subsequent control is not performed (step 13).

When the hydraulic cylinders 19 and 20 are switched from the hard mode to the soft mode (step 6), the supply valve 16 is opened (step 7) and at the same time the timer is reset (step 8).

Since the ignition switch is turned off and the timer is reset almost at the same time, FIG.
In the time chart of, the ignition key OF
At the same time as F, the supply valve 16 is opened (ON) and the hydraulic cylinders 19 and 20 are switched from the hard mode to the soft mode.

By thus setting the hydraulic cylinders 19 and 20 in the soft mode, the pistons of the hydraulic cylinders 19 and 20 can be easily moved. Therefore, when the supply valve 16 is opened, the supply and discharge passages communicated with each other. Air quickly flows within 15, and the vehicle rapidly changes its posture in a flat direction where there is no difference in vehicle height between the left and right sides.

Even if the vehicle changes its posture and becomes flat as described above, the vehicle passes through this flat state due to the inertial force. In other words, a vehicle that had a high vehicle height on the right side and a low vehicle height on the left side at the beginning of the stop passed the flat state, and the vehicle height on the left side was high and the vehicle height on the right side was low. .

When the increase in the vehicle height on the left side stops (step 9), the hydraulic cylinders 19 and 20 are switched to the hard mode (step 10).

At this time, the degree of unbalance between the left and right vehicle heights after passing through the flat state depends on the hydraulic cylinder 1.
It is smaller than it was when the vehicle was stopped because it was attenuated by 9 and 20.

Therefore, even when the hydraulic cylinders 19 and 20 are in the hard mode, the right side of the vehicle rises and the left side of the vehicle descends, the unbalanced state is eliminated in a short time, and the vehicle becomes flat. . After that, the timer is turned off (step 11), the supply valve 16 is closed (steps 12 and 13), and the vehicle height control is ended (step 1).
3).

As a result, the opening time of the supply valve 16 can be greatly shortened, the power consumption is reduced, and the load on the battery is reduced.

That is, as shown in the graph of sprung speed in FIG. 5, the above-described movement of the vehicle gradually increases downward on the right side of the vehicle whose initial vehicle height is higher than the reference position. While moving, hydraulic cylinder 1
The damping action of 9 and 20 causes the hydraulic cylinders 19 and 2 to stop slightly below the reference position (point P in FIG. 5) and to move upward, but at this point P in FIG.
0 is set to hard mode.

The time chart shown in FIG. 6 is shown in FIG.
The pressure reducing cylinders 19 and 20 are switched to the hard mode when the vertical speed reaches a value close to 0 (= threshold value α) in step 9 of the flowchart shown in FIG. 6 (point P in FIG. 6).

Therefore, in the case of FIG. 6, the point where the sprung speed is 0 can be brought closer to the flat position of the vehicle as compared with the case of FIG. 5, and as a result, the depressurizing cylinders 19 and 20 are hardened. When the mode is set, the time until the vehicle height becomes flat can be further shortened.

Here, the threshold value α is optimally set according to the vehicle weight and the magnitude of the damping force of the hydraulic cylinders 19 and 20.

The present invention is not limited to the above-described embodiment, and for example, a G sensor 33 may be installed on the rear wheel side so that the vehicle height can be adjusted before and after the vehicle. .

[0037]

As described above, according to the present invention, when the vehicle stops with the damping force of the damping force varying mechanism being large and the vehicle height needs to be adjusted at this time, the damping force varying mechanism operates. Since the damping force is reduced and the supply / discharge passage for the working fluid provided in the vehicle height adjusting mechanism is communicated by the valve means, the resistance force of the damping force varying mechanism is reduced and the vehicle can be quickly brought close to a flat state. .

Therefore, as compared with the case where the vehicle height is adjusted while the damping force of the damping force varying mechanism is large, the time until the vehicle becomes flat can be shortened, the time for which the valve means is opened can be shortened, and power saving can be achieved. The load on the battery can be reduced.

[Brief description of drawings]

FIG. 1 is a complaint correspondence diagram.

FIG. 2 is a schematic explanatory view of an embodiment of the present invention.

FIG. 3 is a sectional view of a hydraulic cylinder having an air spring.

FIG. 4 is a flowchart diagram.

FIG. 5 is a time chart diagram.

FIG. 6 is another time chart diagram.

[Explanation of symbols]

 10 ... Air pressure source (pressure source) 15 ... Supply / discharge passage 16 ... Supply valve (valve means) 17 ... Control means 18, 21 ... Air spring (vehicle height adjusting mechanism) 19, 20 ... Hydraulic cylinder (hydraulic pressure adjusting means) ) 32 ... Vehicle height sensor (vehicle height detecting means) 33 ... G sensor (vertical speed detecting means) 34 ... Key OFF sensor (key OFF detecting means)

Claims (1)

[Claims] 1. A vehicle height adjusting mechanism for adjusting a vehicle height for each wheel by supplying and discharging a working fluid from a pressure source, and a vibration input from a road surface through a suspension device is attenuated. In a vehicle height adjusting device having a damping force variable mechanism that changes the damping force according to the running state of the vehicle, valve means for communicating the supply and discharge passages of the working fluid provided in each vehicle height adjusting mechanism with each other and an ignition Key OFF detection means for detecting that the vehicle has been turned off, vehicle height detection means for detecting a vehicle height, vertical speed detection means for detecting a change in vehicle height, and detection of ignition OFF detected by the key OFF detection means. The damping force of the damping force varying mechanism is reduced based on the signal, and when the vertical velocity of the vehicle height detected by the vertical velocity detecting means is 0 or close to 0, the damping force of the damping force varying mechanism is damped. A vehicle height adjusting device comprising a control means for increasing the force.