JPS6140572Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vehicle height adjustment device for an automobile.

In an automobile wheel suspension system that uses an air suspension that utilizes the volumetric elasticity of air sealed inside, the vehicle height is raised by supplying air from the outside to the air sealed part of the air suspension. Vehicle height can be lowered by discharging the enclosed air to the outside.

Therefore, a vehicle height sensor consisting of a combination of a bar magnet and two magnetic sensors that operate in response to the magnetism of the bar magnet is installed inside the air enclosure of the air suspension. A device has already been developed that automatically adjusts the vehicle height by detecting the relative height position of the pension and supplying or discharging air into the air-sealed part of the air suspension based on the signal from the vehicle height sensor. (For example, see Japanese Patent Application Laid-Open No. 120131/1983).

In an automobile, it is desirable to lower the vehicle height from the standpoint of driving stability, but lowering the vehicle height may cause problems such as the various equipment installed on the vehicle body or under the floor being grounded and damaged when driving on rough roads. arise.

Therefore, in cars using air suspension, when the vehicle speed is above a certain value, the vehicle height is lowered to improve driving stability, and when the vehicle speed is below the above certain value, the vehicle height is raised to prevent the vehicle from touching the ground. A device has been developed that allows
(see publication).

However, it is not possible to judge whether the road is good or bad depending on whether the vehicle speed is above or below a certain value. If you repeatedly accelerate and decelerate in traffic jams while driving, not only will you have to make unnecessary vehicle height adjustments each time, but you may also drive on gravel roads at a speed higher than the set speed, and in this case, the vehicle height may change. If the floor space is low, there are many disadvantages such as the risk of damaging equipment installed under the floor due to pebbles thrown up.

The present invention is intended to address the problems of the conventional device as described above, and will be described below with reference to the accompanying drawings.

Figure 1 is a diagram showing the air supply and exhaust systems of air suspensions A, B, C, and D for the front, left, and right wheels. In Figure 1, 1 is a compressor, 2 is a dryer,
3 is a reserve tank, and when compressor 1 is driven, air is supplied to dryer 2 and solenoid valve L1.
The air is press-fitted and stored in the reserve tank 3 through the air suspensions A, B, C, and D. Based on the signal from the vehicle height sensor installed in each air suspension A, B, C, and D, the air press-fitted and stored in the reserve tank 3 is Supply air to air suspensions A, B, C, and D to raise the vehicle height, or open exhaust valve L2 to exhaust the air in each air suspension A, B, C, and D to the outside of the vehicle. It is now possible to lower the height.

L3, L4, L5, and L6 are supply/exhaust solenoid valves that control the supply/exhaust of each air suspension A, B, C, and D, respectively.

4 is a pressure sensor which, when the air pressure in the reserve tank 3 falls below a predetermined value, activates the drive control solenoid L7 of the compressor 1 to drive the compressor 1, supply air to the reserve tank 3, and restore the reserve. The air pressure inside the tank 3 is maintained at a predetermined value.

Reference numeral 5 denotes a control device, and the control device 5 controls inputs such as the signals from the vehicle height sensor and the pressure sensor 4 to the corresponding solenoid valves L1 to L6 and the compressor drive control solenoid L7. It controls energization. 6 indicates a power source.

In the above device, for example, when the air suspension A becomes lower than a predetermined height, the vehicle height sensor installed in the air suspension A issues an up signal to the control device 5, and the control device 5 Based on the signal
It emits an output signal to open the solenoid valves L1 and L3, and when L1 and L3 open, the reserve tank 3
Air is supplied to suspension A, and when the vehicle height reaches a predetermined level, L1 and L
3 closes.

Conversely, when the vehicle height of air suspension A becomes too high, the vehicle height sensor issues a down signal to the control device 5, and the down signal opens solenoid valves L3 and L2, and the air in air suspension A is When the vehicle is discharged to the outside and the vehicle height is lowered to a predetermined height, L3 and L2 close as described above.

In this way, the vehicle height of the front, rear, left, and right air suspensions are all independently and automatically controlled to maintain the correct vehicle height at all times.

In the above, the vehicle height sensor installed in each air suspension is generally constructed as shown in FIG. 2. That is, for example, a cylindrical body 11 is attached to the side of a wheel support member such as a suspension arm, and a rod 12 is slidably fitted into the body and attached to the vehicle body side through an elastic material such as a mount rubber at the upper end.
In an air suspension in which an air-tight air sealing part 13 is formed on the outer periphery of a telescopic member 10, the telescopic member 10 has two parts that are relatively telescopically displaced.
A magnet 14 is provided on one of the members, for example, the cylindrical body 11, and a vehicle height sensor 15 consisting of a switch such as a reed switch that operates in response to the magnetism of the magnet 14, such as a reed switch, is provided on the other side, for example, on the rod 12 side. The position where the vehicle height sensor 15 is close to and facing the magnet 14 is set as a reference vehicle height, and when the vehicle height sensor 15 displaces above it, it issues a down signal, and when it displaces it below, it issues an up signal to the control device 5 shown in the first figure. It is configured to always maintain the standard vehicle height.

In the present invention, the vehicle height sensor is configured by combining a low vehicle height sensor 15a and a high vehicle height sensor 15b as shown in FIG. Based on the respective signals of the drive system sensor 7 that detects whether the vehicle is being driven or not and the vertical acceleration sensor 8 that detects the vertical acceleration of the vehicle body, a switching signal for the vehicle height sensor is issued, and the switch signal 15a for low vehicle height and for high vehicle height is generated. 15b, the reference vehicle height can be switched to two levels, low and high.

Vehicles that are capable of switching from two-wheel drive to four-wheel drive (hereinafter referred to as 4WD vehicles) cannot be used when driving on gravel roads or rough roads that are prone to slipping, such as during rainy weather. To prevent slips, it is common to switch to four-wheel drive (hereinafter referred to as 4WD).

Therefore, if the drive system sensor 7 detects that the vehicle is in a 4WD state, and the vertical acceleration of the vehicle body exceeds a predetermined value, there is almost no doubt that the vehicle is traveling on a rough road.

Therefore, in the present invention, when the drive system sensor 7 detects 4WD and the vertical acceleration sensor 8 detects a vertical acceleration of the vehicle body exceeding a predetermined value, the rough road determination circuit in the control device 5 determines that the vehicle is traveling on a rough road. The vehicle height sensor is automatically switched to the high vehicle height 15b side to control the vehicle height at the high standard vehicle height b, and at other times, the low vehicle height 15a side is set to control the vehicle height at the low standard vehicle height a. It is designed to control the height.

A specific example of the rough road determination circuit is shown in FIG.

In FIG. 4, the signal from the vertical acceleration sensor 8 is voltage-converted and compared with the reference voltage of the reference voltage generation circuit 9 by a comparator (COMP). When the vertical acceleration is smaller than a predetermined value, the comparator (COMP) It is assumed that the output signal becomes 0, and when it becomes large, the output signal becomes 1. It is also assumed that the drive system sensor 7 emits a signal of 1 when the vehicle is in 4WD and 0 when the vehicle is in 2-wheel drive, that is, 2WD.

If the vertical acceleration is below a predetermined value when driving in 4WD, the output signal of the comparator (COMP) is 0, which is inverted at note N and becomes 1, which is input to the first AND circuit AND1. Since the signal from the drive system sensor 7 is 1, the output of the AND circuit AND1 becomes 1 and is input to the bistable multivibrator BM.

On the other hand, the output signal 0 of the comparator (COMP) is directly input to the bistable multivibrator BM, and in this state, the output of the bistable multivibrator BM is 0.

The output signal of the bistable multivibrator BM is input to the second AND circuit AND2, and is ANDed with the signal of the drive system sensor 7, so that the output of the AND circuit AND2 is input to the vehicle height sensor switching circuit S. As shown above, when the output of the bistable multivibrator BM is 0,
The output of AND2 becomes 0, and the vehicle height is 15 for low vehicle height.
The vehicle height is controlled at a lower reference vehicle height a by a.

If the signal of the drive system sensor 7 is 0, that is, 2WD
In this case, whether the output of the bistable multivibrator BM is 0 or 1, the output of AND2 is 0, and the vehicle height is controlled by the sensor on the low vehicle height 15a side as described above.

When the vertical acceleration becomes larger than a predetermined value in the 4WD state and the output signal of the comparator (COMP) becomes 1, the input signal of the bistable multivibrator BM changes from 1, 0 to 0, 1, and its output becomes 1. Then, the output of AND2 becomes 1, the vehicle height sensor is switched to the high vehicle height 15b side via the vehicle height sensor switching circuit S, and air is supplied to each air suspension by the device shown in the first figure. The vehicle height is raised, and thereafter vehicle height control is performed at the high reference vehicle height b.

As described above, according to the present invention, when a 4WD vehicle is in 4WD mode and the vertical acceleration of the vehicle body is above a predetermined value, it is determined that the vehicle is driving on a rough road, and the vehicle height is automatically raised and the vehicle is raised to a higher standard vehicle height. The system is configured to control the vehicle height at the vehicle height, lower the vehicle height at other times, and control the vehicle height at a low standard vehicle height.It is able to accurately judge driving conditions on rough roads and raise the vehicle height on good roads. There is no needless operation to lower the vehicle, and the vehicle height is always kept low to improve driving stability, and the vehicle height is reliably raised on rough roads to accurately avoid accidents such as grounding and damage to the vehicle body and under-floor parts. This is something that can bring about great practical effects.

The illustrated embodiment shows an example in which vehicle height sensors are installed in two stages, one for low vehicle height and one for high vehicle height, and are configured to automatically switch between them. It is also possible to install three levels of heights and control switching between these levels depending on the road surface condition.

In addition, the embodiment shown in Fig. 4 shows an example in which the vertical acceleration is converted into voltage and compared with the reference voltage. An output signal may be generated when the value exceeds a reference value.

[Brief explanation of the drawing]

The attached drawings show an embodiment of the present invention, and FIG. 1 is an explanatory diagram showing an example of an air suspension air supply/exhaust control system, FIG. 2 is a sectional view showing an example of the structure of an air suspension, and FIG. FIG. 2 is a front view of the vehicle height sensor, and FIG. 4 is a circuit diagram showing an example of a rough road determination circuit. A, B, C, D...Air suspension, 1...
... Compressor, 3... Reserve tank, 5...
Control device, 6...Power source, 7...Drive system sensor, 8...Vertical acceleration sensor, 14...Magnet, 15...Vehicle height sensor, 15a...Vehicle height sensor for low vehicle height, 15b...High vehicle High vehicle height sensor.

Claims (1)

[Scope of utility model registration request] It uses an air suspension in which air is sealed inside and the vehicle height can be adjusted by supplying air to the air-filled part or discharging the air inside the sealed part to the outside in response to a signal from a vehicle height sensor, and 2. wheel drive and 4
In a car with switchable wheel drive,
The vehicle height sensor described above is composed of two sets of vehicle height sensor for low vehicle height and vehicle height sensor for high vehicle height.
A drive method sensor that detects whether the vehicle is wheel drive or a vertical acceleration sensor that detects the vertical acceleration of the vehicle body is provided, and when the vehicle is in four-wheel drive and the vertical acceleration of the vehicle body is greater than a predetermined value, the above-mentioned A vehicle height adjustment device for an automobile, comprising a rough road determination circuit that switches a vehicle height sensor from a vehicle height sensor for low vehicle heights to a vehicle height sensor for high vehicle heights.