JPS5836711A - Ground clearance adjuster - Google Patents

Abstract

PURPOSE:To enable ground clearance adjustment in emergency by providing an emergency indication switch. CONSTITUTION:Compressed air is supplied from a compressor 5 to suspensions 1-4 through valves 7, 8, 10 to adjust car height. A car height controller 20 controls opening and closing valves 7, 8, 10 and a motor 6 on the basis of the signals from potentiometers 12-15 and car speed signals from a phototransistor 30. Signals from an emergency switch IIS of an operation board 27 are also inputted to CPU of the controller 20 and the ground clearance is raised to a level of safety. Since the ground clearance is adjustable to the height of safety through only operation of the emergency switch IIS regardless of conditions of other switches and the target ground clearance, necessary measures can be easily taken in emergency.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle height adjustment device that maintains the height of a vehicle body relative to an axle at a predetermined value.

In a vehicle, a suspension device is inserted between the axle and the vehicle body in order to prevent vibrations from the axle from propagating to the vehicle body. For this reason, when the vehicle weight increases, the vehicle body sinks, and when the vehicle weight becomes lighter, the vehicle body rises. Also, when braking suddenly, the front of the vehicle sinks (
(nose down), the rear of the car sinks on uphill roads, and the front of the car sinks on downhill roads. Conventionally, a vehicle height sensor is installed between the axle and the vehicle body to detect the vehicle height, and the air pressure of the shock absorber of the suspension system is adjusted so that the detected vehicle height is within a set range (for example, U.S. Patent No. 4.105.216 Class 280 of 1978
). In this type of automatic vehicle height adjustment, feedback control is conventionally performed so that the vehicle height falls within a vehicle height range that is set for the vehicle from the beginning or within a manually set vehicle height range.

The problem with manual setting is, for example, the up instruction switch,
The vehicle is equipped with a down command switch, a vehicle height adjustment stop command switch, etc., and increases the target vehicle height value at predetermined short intervals while the up command switch is closed, and lowers the target vehicle height value while the down command switch is closed. With manual vehicle height adjustment, which stops vehicle height adjustment while the stop instruction switch is closed, if you forget to turn off the switch or do not have enough time to operate the switch, the vehicle height will continue to increase or decrease, causing the vehicle height to rise or fall too much. arise. Furthermore, if there is a step in front of the vehicle, it may not be possible to raise the vehicle height in time even if the up switch is closed, making it difficult to raise the vehicle height as desired in an emergency.

On the other hand, even in vehicle height setting and control that automatically sets the vehicle height target value according to the driving speed, if the road ahead is in poor condition or there is a step, there may be a delay in deceleration and vehicle height adjustment. You may not be able to raise the vehicle height in time.

A first object of the present invention is to provide a vehicle height adjustment device that can change the vehicle height in an emergency, and a second object of the present invention is to provide a vehicle height adjustment device that can quickly set a safe vehicle height in an emergency. shall be.

In order to achieve the above object, the present invention includes an emergency instruction switch, and is configured to set the target vehicle height to a predetermined relatively high value when the switch is in an emergency instruction state (for example, the switch is closed). .

By doing this, if the actual vehicle height is lower than the high target value, the vehicle height will be raised, and if it is higher, the vehicle height will be lowered. maintained at a high value.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is a suspension device on the front right side, 2 is a suspension device on the front left side, 3 is a suspension device on the rear right side, and 4 is a suspension device on the rear left side. The air compressor 5 is driven by a motor M and supplies air to the front suspension system 1.2 via the on-off valve 7.
It is supplied to the rear suspension systems 3 and 4 via. 9 is an air dryer, and 10 is a main system supply/exhaust valve. Energizing motor 6.

Deenergization is controlled by relay 11. The on-off valves 7 and 8 and the supply/exhaust valve 10 are of the solenoid energized type, and the former opens when the solenoid is energized (input/output communication).
The latter switches to exhaust to the atmosphere, and when the solenoid is de-energized, the former is closed (input/output cutoff), and the latter is connected to the human and output dates.

These relays 11 and air control valves 7, 8, and 10 are connected to a driver (amplifier that energizes a coil) 21 of a vehicle height control device 20.

Potentiometers 12 to 15 are mounted on the vehicle body near each suspension device 1 to 4 in association with each other. The rotary shaft (slider) of the potentiometer is connected to the axle via a link. The voltage depending on the height between the axle and the vehicle body is controlled by the potentiometer 12.
13 is a CR filter (smoothing circuit) 2 of the vehicle height control device 20
21, the potentiometer 14.15 applies the voltage to the CR filter 222. The CR filters 221 and 222 each include two diodes that add two human forces, and a CR circuit with a predetermined time constant that receives the output of the diode and smooths its vibration.

The main parts of the vehicle height control device 20 are a central processing unit (CPU) 23t that constitutes a microcomputer, and a semiconductor read-only memory IJ (ROM) 23 with an input/output board.
2 and a semiconductor read/write memory IJ (RAM) 233.

The detected vehicle height of potentiometer 13.15 is directly connected to A/D.
11. applied to the humbatterer 24; , A/D controller, (-evening 2
46ζ is the front detection vehicle height (13) and the rear detection vehicle height (
15), the output of the CR filter 221 (front detected vehicle height envelope value) and the output of 222 (rear detected vehicle height envelope value)
is applied. The input channel of A/D converter 24 is controlled by the signal at the output port of ROM 232. A
The output digital code of the /D converter 24 is stored in the RAM 23.
3 input port. A slit plate 28 of a rotary encoder is connected to the rotating core of the vehicle speed meter cable, and a photosensor consisting of a light emitting diode 29 and a phototransistor 30 detects the movement of the slit. A pulse shaping circuit (amplification circuit) 31 is connected to the emitter of the phototransistor 30, and applies a slit detection pulse to the CPU 231. The CPU 23s counts the slit detection pulses for a predetermined period of time and detects the vehicle speed. The operation board 27 is equipped with an emergency instruction switch IIS and is connected to the input port of the CPU 231.

The ROM 232 contains vehicle speed program data that uses the slit detection pulse to determine the vehicle speed, vehicle height setting program data that sets the target vehicle height according to the vehicle speed, and program data that sets the target vehicle height to a predetermined high level in response to the closing of the emergency instruction switch IIS. Target value change program data to be set in the target value, feedback vehicle height control program data to compare the envelope value with the target value and control the air pressure of the suspension system in the direction where both agree, a determination constant, and target value data associated with the vehicle speed ( 113, 119° 125), and data (X) that determines the permissible control width are stored in a fixed memory in advance, and the CPU advances the control sequence based on these program data and constant data.

FIG. 2a shows a control flow for speed determination and target value setting, and FIG. 2b shows a feedback vehicle height control flow.

First, referring to FIG. 2a, when the program execution progresses to the speed discrimination target value set, the CPU first stores the RAM 233
The number of slit detection pulse counts N=100. The Hals count value A=O is memorized.

Next, the 5Q m5ec program timer is turned on to start the timer and wait for the arrival of the slit detection pulse.
During this time, read the opening and closing of the emergency indication switch IIS, and if it is closed, first set the target vehicle height to a safe value of 154, which is slightly higher than the normal vehicle height range, and then set the target vehicle height to a safe value of 154, which is slightly higher than the normal vehicle height range, and then
Switch flag register E indicates whether IS is closed this time.
Referring to the contents of HFSW, if it is "0", it is assumed that it is closed this time, and "1" indicating the switch is closed is memorized in the register EHFSW, and the motor 6 is turned on and the on-off valve 7,
8 to open and on-off valve 10 to close. Register EH
If the FSW memory is 11", the switch IIS is already
When the motor 6 is read as closed, the motor 6 is turned on to start raising the vehicle height, so the program jumps directly to vehicle height control (Figure 2b). When emergency switch IIS is open, register EHFSW
0 is stored in the memory and waits for the arrival of the slit detection pulse, and when it arrives, the value obtained by adding 1 to A is updated as A. The slit detection pulses are thus counted during one time period of the 50 m5ec program timer, and when one time period is completed, N is updated to N-1, and this is repeated.

And N = 0 (50msec x 100 =
55ec), the value of A (number of slit detection pulses for 5 seconds) is set to the value equivalent to vehicle speed 1100K/h and 60Kf.
Compare with the fl/h equivalent value, and when A≧100 Km/h equivalent value, set the vehicle height target value to a lower value of 113 seconds, 1
When 00 > A ≧60 Km/h equivalent value, it is set to the middle value 119, and when A <60 Km / h equivalent value, it is set to the high value 125.

Next, feedback vehicle height control will be explained with reference to FIG. 2b. When the program execution progresses to this feedback vehicle height control, the CPU first determines the remaining number of sampling times N=100.
．． The number of times the low range exists LCL=0° and the number of times the high range exists LCH=O are memorized. Next, the aforementioned target value set 70-(second a
Read the target value set in Figure), calculate vehicle height lower limit LL = target value - x/2 and vehicle height upper limit UL = target value + If the envelope value Ft is smaller than the lower limit LL, 1 is added to the contents of LCL and this is used as LCL to update the memory (LCL+1→LC
L) L, Ft>UL If the vehicle height envelope value Fl is larger than the upper limit UL, 1 is added to the contents of LCH and this is updated as LCH in the memory (LCH+1→LCH). and 5
After the time limit of 0 m5ec, 1 is subtracted from the remaining sampling number N, the remaining value is set as N, and the update memory (N-1→N
)do. This is then repeated until N=O, that is, 100 times. 100 executions (50msec x 100
= 5 sec), the contents of LCL indicate the number of times the envelope value Fl was less than the lower limit LL out of 100 samplings, and LCH indicates the number of times the envelope value Fl exceeded the upper limit UL out of 100 samplings. . By the time the number of samplings reaches 100, the content of LCL is 51.
If above, the overall vehicle height will tend to be the allowable vehicle height (target planting soil x
/2) is judged to be off to the low side and compressor 5
(motor 6) is set to on and on-off valve 7 is opened (communication)
If the content of LCH is 51 or more, it is assumed that the overall tendency of the vehicle height is higher than the allowable vehicle height, and both the on-off valve 7 and the intake/exhaust valve 10 are set to open. (10
When open, the air is vented to the atmosphere, and when it is closed, the air is supplied. These air supply (pressurization) and exhaust (depressurization) are reset when N=100. Therefore, when the amount of deviation from the allowable vehicle height is large, the faster the LCL > 51 or the LCH > 51, the faster the
Because the exhaust is set quickly, the set time is long and the amount of pressurization and depressurization is large. However, when the amount of deviation is small, LCL〉51 or LcH〉51 if N=O.
Therefore, the set time is short, the amount of pressurization,
The amount of pressure reduction is small. Specifically, when the actual vehicle height (envelope value Fs) fluctuates near the allowable vehicle height, the determination time is long, and even if it is determined that the vehicle height is out of range, the compensation operation time is shortened, and vice versa. If the deviation from the allowable vehicle height is large, the determination time will be short, but the compensation operation time will be long. This allows quick and stable feedback control to be performed.

□ Through the above control operations, while the emergency instruction switch IIS is open, the target vehicle height is set to a value corresponding to the traveling speed, and the vehicle height is adjusted using the actual vehicle height as the target vehicle height. When the emergency indication switch IIS is closed, the target vehicle height is set to a relatively high safe value, regardless of the actual vehicle height and target vehicle height at that time, and the vehicle with the actual vehicle height at that value is set to a relatively high safe value. A high adjustment is made. Therefore, if there is a step in front of the vehicle while traveling at a relatively high speed, the driver closes the emergency instruction switch, and then opens the emergency instruction switch after passing the step and returning to stable driving.

Next, an embodiment including a manual vehicle height setting switch will be described. In this case, the operation board 27 includes a manual vehicle height setting instruction switch MSS as shown in FIG. 3a.

Vehicle height lowering instruction switch DWS, vehicle height increasing instruction switch U
It is equipped with a PS, a vehicle height adjustment stop instruction switch STS, and an emergency instruction switch IIS, and is connected to the CPU 231. Correspondingly, the control operation of the vehicle height control device 20 is as shown in FIGS. 3b and 3c.
In figure b, the part indicated by the two-dot chain line OEI is the 2nd a
It is added to the control flow of speed determination and target value set shown in the figure, and in Figure 3c, the two-dot chain line O
The part indicated by E2 is added to the feedback vehicle height control flow shown in FIG. 2b.

First, the additional part OEI of the control flow for speed determination and target value setting will be explained. If the emergency switch IIS is open, the next step is to read the manual vehicle height setting switch MSS, and if it is open, the process proceeds to setting the vehicle height target value according to the traveling speed, but if MSS is closed, the vehicle height lowering instruction switch is read. Read the opening and closing of the UPS,
If it is closed, the target vehicle height value is updated as the sum of the target vehicle height value and 1 every 41 hours while it is closed, and when the target vehicle height value reaches the upper limit value higher than 154, the target vehicle height value is updated. Fix the high price. When the UPS is open, it reads the opening and closing of the DWS, and if it is closed, the difference obtained by subtracting 1 from the target vehicle height value is updated every 41 hours while it is closed, and the target vehicle height value is updated as the lower limit. When the target vehicle height is reached, the target vehicle height is fixed there. When DWS is open, stop instruction switch S
It reads whether the TS is open or closed, and if it is closed, the motor 6 is turned off while the TS is closed, the on-off valves 7, 8, and 10 are set to close, and the vehicle height adjustment is stopped. When STS is open, the process jumps to feedback control (FIG. 3C). In the feedback control flow shown in Fig. 3C, first, it is determined whether the manual vehicle height setting switch MSS is open or closed, and if it is closed and the stop command switch STS is closed, the vehicle height is not adjusted and the process returns to the main routine, and M-3S is opened. , or when STS is open even if MSS is closed, the vehicle height is adjusted to make the actual vehicle height the target vehicle height.

Note that the manual vehicle height set switch MSS, stop instruction switch STS, and emergency instruction switch IIS are status maintenance types that close when pressed once, open when pressed the next time, and close when pressed the next time. The vehicle height raising instruction switch UPS and vehicle height lowering instruction switch DWS are momentary switches that are closed only while being pressed and return to open when they are no longer pressed. With this switch configuration and control operation, when the driver opens the MSS, the vehicle height is adjusted according to the vehicle speed.
When MSs4 is closed, DWS is open when STS is open,
The vehicle height is adjusted to the set value using the UPS, and constant value vehicle height control is not performed when the STS is closed. switch mss
, DWS, UPS, and STS are opened or closed, when the emergency instruction switch IIS is closed, the vehicle height is adjusted to a relatively high safe value 154. In addition, for both DWS and UPS, MSS; STS, I
1. , S may be a one-button reversal type switch.

In the above description, only the target value set and feedback vehicle height adjustment for the front portion of the vehicle body are referred to, but the target value set and feedback vehicle height adjustment for the rear portion of the vehicle body are performed in the same manner.

Next, other embodiments and modifications of the present invention will be described. In the above embodiment, the target value and allowable range data (X) associated with the vehicle speed are stored in advance in the ROM 232.1. These are fixed. To further manually adjust the target value or control range, enter the amount of change using the operation board 27, and add or subtract the input change amount from the ROM memory value and use it as the target value in the RAM 233 or CPU.
All you have to do is store it in the accumulator register. Or non-volatile semiconductor read/write memo! J (NR
AM) and each of the above constants may be stored therein. Furthermore, in the above embodiment, the envelope value Fl is obtained by the CR filters 221 and 222, that is, the integrating circuit having a discharge time constant, but the instantaneous value N1 is read at a predetermined sampling period and is always stored in the RAM 233 for the past several times. Alternatively, data for several dozen times may be held and the average value thereof may be used as the envelope value F1.

Potentiometers are used as the vehicle height sensors 12 to 15, but these may be replaced with rotary encoders or linear encoders.Also, conventional vehicle height sensors can detect the vehicle height region at a high density pitch. It is best to use something that is moist. If the potentiometer is replaced with an absolute encoder that generates a digital code indicating the rotation angle, the A/D converter 24 can be omitted. However, computer programs and D/A converter CR
It is necessary to obtain an envelope value using a filter A/D converter.

As described above, according to the present invention, when the emergency instruction switch closes and -
When this happens, the target vehicle height is set to a relatively high safe value, regardless of the operation status of other switches or the target vehicle height value at that time, and the vehicle that attempts to set the actual vehicle height to that value. High adjustments are made and emergency response becomes easier.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2a and 2b are flowcharts showing control operations of the vehicle height control device 20 shown in FIG. 1, respectively. FIG. 3a is a circuit diagram showing a modified portion of another embodiment of the present invention, and FIGS. 3b and 3c are flow charts showing the control operation of the vehicle height control device of this embodiment, respectively. 1 to 4: Suspension device 5: Air compressor (pressurized fluid supply means)

Claims (1)

[Claims] A vehicle height sensor that detects the height between the axle and the vehicle body, a pressurized fluid supply means that provides shock absorber fluid pressure for a suspension system that is located between the axle and the vehicle body and supports the vehicle body, and a valve means that controls the shock absorber fluid pressure. In a vehicle height adjustment device equipped with an automatic vehicle height control device that compares a vehicle height detected by a vehicle height sensor with a target vehicle height and controls the energization of a pressurized fluid supply means and a valve means in a direction in which the two match, an emergency A vehicle height control device comprising an instruction switch, wherein the vehicle height control device sets a target vehicle height to a predetermined relatively high value while the switch is in an emergency instruction state and performs the automatic vehicle height control. Adjustment device.