JPS6082420A - Car-height adjuster - Google Patents

Abstract

PURPOSE:To prevent overshoot and undershoot by controlling the car-height speed so as to be high when the difference between a detected car-height and an amid car-height is larger than a prescribed value and low when the difference is smaller. CONSTITUTION:Each detected car-height signal of car-height sensors 40A-40C is input into a control circuit 60. Said control circuit 60 determines an aimed car-height and calculates the difference between the aimed car-height and a detected car-height by the aid of the operation signal of a manual switch 70 and according to a prescribed program, and compares said difference value with a set difference value. When the calculated difference value is larger than the set difference value, car-height adjustment is performed speedily by putting solenoids 23A-23C or solenoids 32A-32C into continuous electric conduction with a duty ratio of 100%. When the difference is smaller than the set value, the car-height adjusting speed is reduced by transmitting intermittent signals with a duty ratio T2/T1 into the solenoids 23A-23C and 32A-32C. Thus, overshoot and undershoot can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a vehicle height adjustment device, and particularly to a device for controlling the speed of vehicle height adjustment.

[Prior art]

When the vehicle height has not yet reached the target vehicle height, it is desirable to reach the target vehicle height within a short period of time, and therefore efforts are being made to increase the vehicle height adjustment speed.

However, if the adjustment speed is fast, even if the vehicle height reaches the target vehicle height, the vehicle cannot be stopped immediately and the vehicle overshoots or undershoots, resulting in a hunting phenomenon.

[Purpose of the invention]

In view of these conventional problems, an object of the present invention is to slow down the vehicle height adjustment speed when the vehicle height approaches the target vehicle height. The purpose is to stop without overshooting or undershooting at high temperatures.

C. Configuration of the Invention] The configuration of the present invention for achieving this object will be explained with reference to FIG.

The actuator forms a fluid pressure chamber between the vehicle body side member and the wheel side member of the suspension system, and adjusts the vehicle height by supplying and discharging fluid pressure such as hydraulic pressure or air pressure to this fluid pressure chamber. It is like that.

A fluid pressure supply means and a fluid pressure discharge means are connected to the fluid pressure chamber of the actuator, the fluid pressure supply means supplies fluid pressure to the fluid pressure chamber in order to increase the vehicle height, and the fluid pressure discharge means: Fluid pressure is discharged from the fluid pressure chamber to lower the vehicle height.

On the other hand, a vehicle height sensor that detects the vehicle height is provided, and the flow rate control means controls the flow velocity of the fluid pressure supplied or discharged by the fluid pressure supply means or the fluid pressure discharge means to the vehicle height detected by the vehicle height sensor. When the difference between the vehicle height and the target vehicle height is greater than a predetermined value, the vehicle speed is increased, and when the difference is smaller than the predetermined value, the vehicle speed is decreased.

[Function and effect of the invention]

According to the present invention, the vehicle height is adjusted quickly until it approaches the target vehicle height, but then it is adjusted slowly when the vehicle height reaches the target vehicle height. Don't shoot or undershoot.

Therefore, hunting operation near the target vehicle height can be eliminated.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a fluid pressure circuit of one embodiment, in which hydraulic pressure is used as the fluid pressure. Here, IOA~I
OD is a hydropneumatic suspension engine unit (actuator) installed corresponding to the four wheels.
10A corresponds to the left front wheel, 10B corresponds to the right front wheel, IOC corresponds to the left rear wheel, and IOD corresponds to the right rear wheel. The cylinder 15 of each suspension unit IOA to IOD is attached to the vehicle body, and the piston 12 is attached to a suspension member of each wheel. cylinder 15
Inside, by the diaphragm 14 and the piston 12,
A high pressure gas chamber 13 and a hydraulic chamber (fluid pressure chamber) 11 are formed. The high-pressure gas chamber 13 is used to reduce the impact that is transmitted to the vehicle body due to the vertical movement of the cylinder. Although not shown, the hydraulic chamber 11 has a vibration damping mechanism.
It is designed to attenuate relative vibration between the wheels and the vehicle body, and the vehicle height is adjusted by supplying and discharging oil to the hydraulic chamber 11.

Hydraulic chamber 11 of each suspension unit IOA to IOD
To adjust the vehicle height, a hydraulic pump 21 and switching valves 22A to 22C, which are fluid pressure supply means, are connected, as well as switching valves 31A to 31G, which are fluid pressure discharge means. Each switching valve 22A to 22C and switching valve 31
A to 31G are integrated, and each switching valve is connected to a corresponding solenoid 23A to 23.
These are electromagnetic valves that are excited and operated by energizing c132A to c132C.

The mutually integrated switching valves 22A and 31A are connected to the hydraulic chamber 11 of the suspension unit IOA via a one-way delay valve 82A, and are connected to the hydraulic chamber 11 of the suspension unit IOA through a one-way delay valve 82A.
The flow dividers 83A and 83c1 are also connected to the hydraulic pump 21 via the pressure regulator 85).

In addition, the mutually integrated switching valves 22E3.31B are
Suspension unit I via one-way delay valve 82B
In addition to being connected to the hydraulic chamber 11 of the OB, the reservoir 81
B, and also flow dividers 83'A, 83
C. It is connected to the hydraulic pump 21 via the pre-noise regulator 85).

The integrated switching valves 22C and 31 (1;!) are connected to the hydraulic chamber 11 of the suspension engine unit 10C via the flow divider 83B1 and the one-way delay valve 82C, and via the flow divider 83B1 and the one-way delay valve 82D. The switching valves 22C and 131C are connected to the hydraulic chambers 11 of the suspension unit IOD, respectively.Furthermore, the switching valves 22C and 131C are connected to the reservoir 81C, and the hydraulic pressure 1 and 2 are connected to each other via the flow divider 83C and the pressure regulator 85.
Connected to 1.

Note that each one-way delay valve 82A to 82D does not delay the supply when supplying oil to the idle pressure chamber 11 of each suspension unit IOA to 10D, and does not delay the discharge when discharging oil from the hydraulic chamber 11. is configured to delay.

The hydraulic pump 21 pumps up oil from the reservoir 84 and discharges it to the pressure regulator 85, and the pressure regulator 85 adjusts the oil pressure to a constant oil pressure. When the pressure regulator 85 adjusts the oil pressure, excess oil is returned to the reservoir 84.

Therefore, the solenoid 23A is energized and the switching valve 22A
When the switching operation is performed, the oil from the hydraulic pump 21, which has been adjusted to a constant oil pressure by the pressure regulator 85, flows through the switching valve 22A via the flow dividers 83C and 83A.
Further, the hydraulic pressure is supplied to the hydraulic chamber 11 of the suspension unit 1°A via the one-way delay valve 82A. For this reason,
The vehicle height of the left front of the vehicle is raised.

Similarly, the solenoid 23B is energized and the switching valve 22B
When the switching operation is performed, the oil of the hydraulic pump 21 flows through the switching valve 22B via the flow dividers 83C and 83A, and is further supplied to the hydraulic chamber 11 of the suspension unit IOB via the one-way delay valve 82B. be done. Therefore, the height of the right front portion of the vehicle is increased.

Further, when the solenoid 23C is energized and the switching valve 22C is switched, the oil in the hydraulic pump 21 flows to the switching valve 22G via the flow divider 83C, and further flows through the flow divider 83B and the one-way delay valve 82C. and is supplied to the hydraulic chamber of the suspension unit 10C. In addition, the oil flowing to the switching valve 22C is transferred to the flow divider 83B.
and is supplied to the hydraulic chamber of the suspension unit 10D via the one-way delay valve 82D. Therefore, the vehicle height at the rear of the vehicle is raised.

On the other hand, when the solenoid 32A is energized and the switching valve 3IA is switched, the oil in the hydraulic chamber 11 of the suspension unit IOA is discharged to the reservoir 81A via the one-way delay valve 82A, and the vehicle height at the left front of the vehicle is descend.

Further, when the solenoid 32B is energized and the switching valve 31B is switched, the oil in the hydraulic chamber 11 of the suspension unit IOB is drained through the one-way delay valve 82B'i-.
The water is discharged to the reservoir 81B, and the height of the right front of the vehicle is lowered.

Further, when the solenoid 32C is energized and the switching valve 31C is operated, the oil in the hydraulic chamber of the suspension unit 10C is discharged to the resurper 81C via the one-way delay valve 82G and the flow divider 83B, and the one-way The oil is discharged to the oil reservoir 81C in the hydraulic chamber of the suspension unit IOD via the delay valve 82D and the flow divider 83B, thereby lowering the vehicle height at the rear of the vehicle.

Figure 3 shows each solenoid 23A to 23C, 32A to 32.
A control circuit for controlling energization of G is shown. The control circuit 60 consists of a microcomputer 62, an inlet sofa 61, and a driver 63.
2 is a general-purpose one, and a large buffer 61 inputs signals from vehicle height sensors 40A to 40C1 and a manual switch 70 to a microcontroller/computer 62, and a driver 63.
are connected so that each solenoid 23A-23C, 32, A-32C is energized by a signal output from the microcomputer 62.

The vehicle height sensors 40A to 40C are configured to detect the vehicle height near the left front wheel, right front wheel, and rear wheel, respectively, and generate a detection signal using a 4-bit binary signal. 4 sets of photosensors 41a to 41d, 4
2a to 42d, and a light shielding plate (not shown) attached to the wheel side. The outputs of the phototransistors 42a to 42d are "1" and "1" of each bit.
The vehicle height is expressed by a combination of "0" signals.

For example, the detection signals generated by the vehicle height sensors 40A to 40C are as shown in FIG.

FIG. 4 shows the state of each bit signal of the vehicle height sensors 40A to 40C from the bound position to the rebound position in the suspension units 10A to 10D, and the signal from the phototransistor 42d is "H" as shown in "H".
A signal whose states change between "1" and "0" is generated, and from the phototransistor 42C, H2 and the phototransistor 42
From phototransistor 42a, H
A signal such as 6 is generated. Therefore, when the vehicle height is in the low position, a signal of ro 110J is generated from each bit of the vehicle height sensors 40A to 40C.
A signal of J is generated.

The manual switch 70 is composed of one movable contact 71 and four fixed contacts 72 to 75, and is configured to output a ground signal from the fixed contacts 72 to 75 in contact with the movable contact 71. Here, the signal from fixed contact 72 represents high level, the signal from fixed contact 73 represents normal level, the signal from fixed contact 74 represents auto, and the signal from fixed contact 75 represents vehicle height at low level. Entering cover・
The data is inputted to the microcomputer 62 via the 7-face 61.

The microcomputer 62 operates according to a program stored in a ROM (not shown) as is well known.
The program will be explained with reference to the flowchart shown in FIG.

When the program is started in step S1, initialization is performed in step S2, each subsequent step is sequentially processed, and the program is terminated in step S15. After that, the program starts from step S3. Step S1
Steps 5 to 5 are repeated.

In step 7''S3, data on the current vehicle height is input based on the operation of the manual switch notch 70 and the state of the vehicle height, based on the detection signals of the vehicle height sensors 40A to 40C.

Next, in step S4, the difference between the current signal and the target vehicle height is
It is determined whether the amount is larger than a set amount h2. As shown in Fig. 4, this set amount h2 is set to the bound position side or rebound position G with respect to each target vehicle height of the low position, normal position, and high position. A setting amount of about half the setting amount h2 is set around the height.

Currently, the current vehicle height is far away from the target vehicle height.
An affirmative determination is made in step S4 that the difference between the two is 0 people than the set amount h2, and the process proceeds to steps S5 to S7. In step S5, a driving number counter, which will be described later, is reset. Further, in step S6, the vehicle height adjustment flag is set to record that the vehicle height adjustment is in progress. Furthermore, in step S7, the solenoids 23A to 23C1
Or duty ratio 10 for solenoids 32A to 32C.
Continuously energize at 0% to raise or lower the vehicle height. However, when the current vehicle height becomes close to the target vehicle height and the difference between the two becomes smaller than the set amount h2, a negative determination is made in step S4, and the process proceeds to step S8, where the vehicle height adjustment flag is set to Determine whether or not. At this time, if the vehicle height is not being adjusted and the vehicle height adjustment flag is not set, a negative determination is made in step S8, and step S
Proceeding to step S15, if the vehicle height is lllll rough set during vehicle height adjustment, an affirmative determination is made in step S8.
Proceed to step S9. In step S9, it is further determined whether the difference between the current vehicle height and the target vehicle height is greater than a set amount. At this time, if the current vehicle height is still far apart from the target vehicle height by more than the set amount, an affirmative determination is made in step S9, and the process proceeds to step SIO and step 311. In step SIO, the solenoids 23A to 23C
Alternatively, an intermittent signal with a duty ratio T2/TI is output to 32A to 32C. This intermittent signal is a signal that is intermittent at a cycle that is sufficiently faster than the oil supply and discharge speed to and from the oil JE chamber of each suspension unit IOA to 10D.
As a result, oil is slowly supplied and discharged from the hydraulic chamber, and the vehicle height rises and falls at a slower speed. Further, in step Sll, the number of intermittent signals outputted in step S10 is counted by a driving number counter.

Then, the count value of the driving number counter at this time is stored as N. On the other hand, when the current signal approaches the target vehicle height and the difference between the two becomes smaller than the set amount h1, a negative determination is made in step S9 and the process proceeds to step S12, where the count value N2 of the driving number counter is It is determined whether the stored count value N is greater than α times the stored count value N. Count value N
2 does not reach α・N, the process proceeds to step S13 and step 7''S14, and in step S13, similarly to step SIO, the signal of the duty ratio of T z /T + is sent to each solenoid 23A to 23C or 32A. ~
Output to 32C. Further, in step S14, the number of intermittences of this duty signal is counted by a driving number counter,
The count value is stored as N2. Eventually, the count value N2
When becomes larger than α·N, an affirmative determination is made in step S12, and the process proceeds to step S15.
13 is stopped from outputting the duty signal. In addition,
The constant α is given by h+/hz h+.

In other words, when the current vehicle height is far away from the target vehicle height, the vehicle height is raised or lowered at a relatively fast speed in order to reach the target vehicle height quickly, and the current vehicle height is changed from the target vehicle height. When approaching a range that is a set distance from high,
The vehicle height is raised or lowered at a relatively slow speed to prevent overshoot or undershoot. The current vehicle height approaches the target vehicle height, and the difference is the set amount hI.
□) If the vehicle falls within the range, the difference between the current vehicle height and the target vehicle height is adjusted by the set amount h2 in order to accurately match the current signal to the target vehicle height.
The number of pulses of the duty signal is α times the number of pulses from when the duty control is started until the difference between the current vehicle height and the target vehicle height enters the range of the set amount h1. Output.

In addition, in the flowchart of FIG. 5, step S7
．． 10.13 corresponds to the flow rate control means of the present invention.

Next, the operation when changing the vehicle height from the normal position to the high position will be explained with reference to FIG. 6. By operating the manual switch 70 or changing the vehicle height,
When the target vehicle height changes from the normal position to the high position at time tl, the solenoids 23A to 23C are continuously energized and the vehicle height is raised at a relatively fast speed. At the time of t2,
When the current vehicle height rises to a vehicle height that is lower than the target vehicle height by a set amount h2, the energization signals to the solenoids 23A to 23C are switched to the duty signal. This duty signal is
The period is T1, and the energization time is T2.

Therefore, the rate of increase in vehicle height is slowed down here.

At time t3, the current vehicle height is set higher than the target vehicle height.

After that, from t2 to t3
The solenoids 23A to 23C are energized with a pulse signal having a number of pulses α times the number of pulses up to .

Here, since α is set as +/hzh+, the vehicle height is exactly at the high position at time t when the duty signals are energized to the solenoids 23A to 23C.

Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and includes various embodiments within the scope of the claims. For example, compressed air pressure can also be used as the fluid pressure. Further, the flow rate control means may be configured to control only the flow rate of either supply or discharge of fluid pressure.

[Brief explanation of the drawing]

Fig. 1 is a complaint correspondence diagram, Fig. 2 is a hydraulic circuit diagram of an embodiment of the present invention, Fig. 3 is an electric circuit diagram of an embodiment of the invention, and Fig. 4 is a vehicle height sensor diagram. A diagram explaining the output signal,
FIG. 5 is a flowchart showing the program contents of the microcomputer shown in FIG. 3, and FIG. 6 is a time chart for explaining vehicle height adjustment control. 10A~10 I)------Suspension unit (actuator) 11~--111--Hydraulic chamber (fluid pressure chamber) 2122A~2
2C, 23A~23 C------Fluid fluid pressure supply means 21------One hydraulic bomb 22A~22 G---Switching valve 23A~23 C---------Solenoid 32A~
32C 31A~31C132A~32 C------Full fluid pressure discharge means 31A~31 C------All changeover valve 32A~32
C---Solenoid 40A~40G-----Vehicle height sensor 60----
Control circuit 70--Manual switch Applicant: Toyota 1.1 Body Type Company

Claims (1)

[Claims] 1. A fluid pressure chamber is formed between the vehicle body side member of the suspension system and the wheel support member, and fluid pressure such as hydraulic pressure or air pressure is supplied and discharged to this fluid pressure chamber. an actuator adapted to adjust the vehicle height; and a fluid pressure supply means for supplying fluid pressure to a fluid pressure chamber of the actuator to increase the vehicle height.
To lower the vehicle height, fluid pressure is supplied or discharged by a fluid pressure discharging means for discharging fluid pressure from the fluid pressure chamber of the actuator, a vehicle height sensor for detecting the vehicle height, and a fluid pressure supply means or a fluid pressure discharging means. A flow rate control means for increasing the flow rate of the fluid pressure when the difference between the vehicle height detected by the vehicle height sensor and the target vehicle height is larger than a predetermined value and slowing it when the difference is smaller than the predetermined value. Features a vehicle height adjustment device.