JP2924283B2 - Height control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle height control device for controlling a vehicle height by adjusting a pressure in a fluid chamber included in a suspension, and more particularly, to a vehicle height control apparatus irrespective of the pressure in a fluid chamber such as when jacking up. Even after the vehicle height has risen, the pressure in the fluid chamber can be prevented from abnormally decreasing.

[0002]

2. Description of the Related Art A conventional technique for controlling the vehicle height by adjusting the pressure in a fluid chamber provided with a suspension is disclosed, for example, in Japanese Patent Application Laid-Open No. Sho 62-289417 previously proposed by the present applicant. Something was done. This conventional vehicle height control device controls the vehicle height by adjusting the pressure in a fluid chamber interposed between a sprung portion and an unsprung portion, while forcibly increasing the vehicle height like a jack-up. An abnormality is detected from the vehicle height change speed, and when such an abnormality is detected, the vehicle height control is stopped to prevent an abnormal decrease in the pressure in the fluid chamber. This prevents a problem that the vehicle height becomes abnormally low when the vehicle is lowered.

[0003]

However, in the above-mentioned prior art, since it is configured to judge whether or not the vehicle is in an abnormal state based on the speed of change of the vehicle height, when the vehicle height changes relatively quickly. Although there is no particular problem, if jack-up is performed slowly or intermittently while stopping halfway, it may not be possible to judge that it is abnormal, and it may not be possible to prevent the pressure drop in the fluid chamber. was there.

The present invention has been made in view of such an unsolved problem of the prior art, and the vehicle height is forcibly increased regardless of the pressure in the fluid chamber as in jack-up. It is an object of the present invention to provide a vehicle height control device capable of reliably preventing an abnormal decrease in fluid chamber pressure in such a case.

[0005]

In order to achieve the above object, the present invention provides a suspension including a fluid chamber capable of adjusting a vehicle height by supplying and discharging fluid, a vehicle height detecting means for detecting the vehicle height, Vehicle height adjusting means for supplying a fluid to the fluid chamber or discharging the fluid from the fluid chamber to adjust the vehicle height based on a difference between the vehicle height detected by the vehicle height detecting means and a target vehicle height, In the vehicle height control device provided, the vehicle height is a target vehicle.
Vehicle height determining means for determining whether or not the vehicle height is equal to or higher than a predetermined vehicle height higher than the high region; and
The amount of fluid discharged from the fluid chamber during a period from the time of starting the vehicle height adjustment for discharging the fluid until it is determined that said vehicle height determination means and said vehicle height becomes above or greater than a predetermined vehicle height by increasing a discharge amount measuring means for obtaining and a forced supply means for supplying a flow body to the fluid chamber in response to the measured value of the discharge amount measuring means, the provided.

[0006]

[Function] If the vehicle height rises irrespective of the pressure in the fluid chamber due to jack-up or the like, the difference between the vehicle height and an appropriate target vehicle height increases, so the vehicle height adjusting means discharges fluid from the fluid chamber. Then, the vehicle height approaches the target vehicle height. For this reason, the pressure in the fluid chamber decreases in spite of the increase in the vehicle height, and when the jack is lowered in this state, the vehicle height abnormally decreases.

However, according to the vehicle height control device of the present invention , the target vehicle height basin is set to such an extent that it can be determined that jack-up or the like has been performed.
While the vehicle height determining means monitors whether or not the vehicle height has reached a predetermined vehicle height higher than the predetermined vehicle height, the emission measuring means has increased the vehicle height from the time when the vehicle height adjusting means started the vehicle height adjustment . As a result, the amount of fluid discharged from the fluid chamber until the vehicle height determining means determines that the vehicle height is equal to or higher than the predetermined vehicle height, that is, the amount of fluid discharged from the fluid chamber due to jack-up or the like. the calculated and forced supply means, since the supply flow body the fluid chamber in response to the measured value of the discharge amount measuring means, fluid discharged during the jack-up is compensated, pressure in the fluid chamber is restored.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is a vehicle height control device according to the present invention,
This is applied to a so-called air suspension in which an air chamber is interposed between a sprung portion and an unsprung portion. First, the configuration will be described.

In FIG. 1, a front right wheel, a front left wheel, a rear right wheel,
A suspension 1FR, 1FL, 1R is provided between the vehicle-side member and the wheel-side member at each of the four rear left wheel positions.
R, 1RL is interposed, these suspension 1FR
To 1RL have shock absorbers 2FR to 2RL that generate damping force and air chambers 3FR to 3RL as fluid chambers that support a static load on the vehicle body.

Each of the air chambers 3FR to 3RL is formed by an elastic body 4 made of, for example, rubber or the like, which surrounds a space between a vehicle body-side member (not shown) and the shock absorbers 2FR to 2RL so as to be vertically expandable and contractible. And the air chamber 3F on the front side of the vehicle
Each of R, 3FL is an electromagnetic switching type cut valve 11FR, which maintains a communication state by a biasing force of a spring when a command signal is not supplied from a controller described later.
A line 7 communicating with the discharge side of the compressor 5 through the solenoid valve 11FR and the solenoid-operated supply valves 13FR and 13FL that maintain a shut-off state by the biasing force of a spring when a command signal is not supplied from a controller described later. It is connected to the.

On the other hand, of the air chambers 3RR and 3RL on the rear side of the vehicle,
The air chamber 3RR on the right side of the vehicle body is provided with an electromagnetic switching type cut valve 11RR that maintains a communication state by a biasing force of a spring when a command signal is not supplied from a controller described later.
When a command signal is not supplied from a controller to be described later, the air chamber 3RL on the left side of the vehicle body is connected to the conduit 7 via an electromagnetic switching type supply valve 13R that maintains a shut-off state by the biasing force of a spring. An electromagnetic switching type cut valve 11RL that maintains a communication state by the biasing force of a spring when a command signal is not supplied from a controller described later, and a spring biasing force when a command signal is not supplied from a controller described later. It is connected between the cut valve 11RR and the supply valve 13R via an electromagnetic switching communication valve 15 which maintains a shut-off state.

Also, on the compressor 5 side of the cut valves 11FR to 11RL, accumulators 17FR to 1FR for adjusting the capacity of the air chambers 3FR to 3RL and changing their spring constants are provided.
7RL is connected. That is, the cut valves 11FR to 11RR
Are in communication with each other, the air chambers 3FR to 3RL and the accumulators 17FR to 17RL are in communication with each other.
The spring constant of RL is small, and conversely, the cut valve 11FR
If the air chambers 3FR to 3RL are disconnected from the accumulators 17FR to 17RL, the air conditioners 3FR to 3RL are disconnected.
The spring constants of the air chambers 3FR to 3RL are large.

The discharge side of the compressor 5 and the filter 9 are connected to the suction side of the compressor 5 via a return path 19, and no return signal is supplied to the return path 19 from a controller described later. In this case, an electromagnetic switching type exhaust valve 21 that maintains the shut-off state by the biasing force of the spring is interposed. The compressor 5 receives an output of an electric motor 23 connected to a power source such as a battery (not shown) and is driven to rotate. The electric motor 23 operates according to a command signal supplied from a controller described later. Or take a stop state.

A controller 25 for outputting a command signal to each of the cut valves 11FR to 11RL, the supply valves 13FR, 13FL, 13R, the communication valve 15, the exhaust valve 21, and the electric motor 23 is provided. , Microcomputer not shown, interface circuit,
It is composed of a storage device and the like. Further, the controller 25 includes a vehicle height detection value _HFR detected by a front right wheel height sensor 27 for detecting a vehicle height at a right wheel position on the front side of the vehicle body, and a front left wheel for detecting a vehicle height at a left wheel position on the front side of the vehicle body. a vehicle height sensor 29 detects the vehicle height detected values H _FL, vehicle height detection value H _R that wheel vehicle height sensor 31 has detected after detecting the average vehicle height of the left and right wheel position of the vehicle body rear side, the vehicle speed The detected vehicle speed value V detected by the detected vehicle speed sensor 33 is supplied.

The front right wheel height sensor 27 and the front left wheel height sensor 29 are mounted, for example, near the suspensions 1FR and 1FL, and include a potentiometer or the like for detecting a relative displacement between the vehicle body side member and the wheel side member. Used. Also,
The rear wheel height sensor 31 may be a sensor such as a potentiometer that detects a relative displacement between the rear axle and the vehicle body-side member, or, in the case of a vehicle using a stabilizer, the rotation angle of the central portion of the stabilizer. Can be used.

The controller 25 executes predetermined arithmetic processing based on the supplied detected values and signals and outputs a command signal, thereby adjusting the air pressure of each of the air chambers 3FR to 3RL to adjust the vehicle height. Control to keep the vehicle body horizontal to the road surface within the target vehicle height range. Next, the operation of this embodiment will be described.

First, the contents of the normal vehicle height control executed by the controller 25 will be described.
5 is to determine whether the vehicle height detection values H _FR , H _FL, and H _R supplied from the vehicle height sensors 27, 29, and 31 are within a predetermined target vehicle height region, and if not, Supplies air to the air chambers 3FR to 3RL or discharges air therefrom.

For example, if the vehicle height on the right side of the vehicle body deviates from the target vehicle height region to a lower side, the controller 25
With the exhaust valve 21 kept in the shut-off state, a command signal is supplied to the electric motor 23 to drive the compressor 5, and a command signal is supplied to the supply valve 13 FR to make it communicate with the air chamber 3 FR. The air discharged from the compressor 5 is supplied.

Then, since the internal pressure of the air chamber 3FR rises and the vehicle height on the right side of the vehicle body rises, the supply valve 13FR is closed when the vehicle height falls within the target vehicle height region, and the air chamber 3FR is closed.
Stop supplying air to FR. Conversely, when the vehicle height on the right side of the vehicle body is out of the target vehicle height region, the controller 25 stops the electric motor 23 to put the compressor 5 into a non-driving state, and Valve 1
A command signal is supplied to the 3FR, and the air in the air chamber 3FR is discharged through the pipe 7 and the return path 19.

Then, since the internal pressure of the air chamber 3FR decreases and the vehicle height on the right side of the vehicle body decreases, when the vehicle height falls within the target vehicle height region, the exhaust valve 21 and the supply valve 13FR are shut off, and the air Stop exhaust from chamber 3FR. When the vehicle height adjustment on the right side of the vehicle body is being performed, the supply valve 13FL,
13R is in a cutoff state.

When the vehicle height on the left side of the vehicle body is out of the target vehicle height region, similar control may be performed on the supply valve 13FL. In this manner, the inclination of the vehicle body in the roll direction is eliminated by adjusting the internal pressure of the air chambers 3FR and 3FL on the front wheel side. On the other hand, the inclination of the vehicle body in the pitch direction is eliminated by performing the pressure regulation control by regarding the rear-wheel-side air chambers 3RR and 3RL as one air chamber.

That is, if the vehicle height detection value H _R supplied from the rear wheel vehicle height sensor 31 is within the target vehicle height region, nothing is performed, but the vehicle height detection value H _R is out of the target vehicle height region. In this case, the supply valves 13FR and 13FL are shut off, and a command signal is output to the communication valve 15 to output the air chambers 3RR and 3FL.
The RL was the communicating state, and, if the vehicle height detection value H _R deviates towards low from the target vehicle height region, with the compressor 5 and the driving state and outputs a command signal to the electric motor 23, the supply valve A command signal is output to 13R to make it in a communication state, and air is supplied to the air chambers 3RR and 3RL to raise the vehicle height on the rear side of the vehicle body until the vehicle height falls within the target vehicle height region.

Conversely, when the vehicle height detection value H _R is out of the target vehicle height range, the compressor 5 is stopped, and a command signal is output to the supply valve 13R and the exhaust valve 21 to output them. Air chambers 3RR and 3RL
The inside air is exhausted through the pipe 7 and the return path 19, and the vehicle height on the rear side of the vehicle body is lowered until it falls within the target vehicle height area.

Next, each air chamber 3 is jacked up or the like.
Control when the vehicle height increases regardless of the internal pressures of FR to 3RL will be described. FIG. 2 is a flowchart showing an outline of a process for detecting a situation where the internal pressures of the air chambers 3FR and 3FL are abnormally reduced and recovering the reduced internal pressures. It is executed substantially in parallel by the time sharing method.

First, at step 100, the variables used for this processing are cleared, and then the routine proceeds to step 101, where it is determined whether or not the jack-up control flag JUF has risen. Immediately after the start of the process, since the variables have been cleared in step 100, the determination in step 101 is “NO”, and the process proceeds to step 102.

In step 102, it is determined whether or not the vehicle is stopped based on the vehicle speed detection value V supplied from the vehicle speed sensor 33. If it is determined that the vehicle is running, a special operation such as jack-up is performed. Since no state should occur, the process returns to step 101 without executing the following processing. On the other hand, if it is determined in step 102 that the vehicle is at a stop, the process proceeds to step 103 to determine whether or not the exhaust valve 21 is on. If it is determined that the exhaust valve 21 is off, Since the air is not discharged from the chambers 3FR and 3FL, and the internal pressures of the air chambers 3FR and 3FL do not drop abnormally, the process returns to step 101 without executing the following processing.

However, if it is determined in step 103 that the exhaust valve 21 is ON, it means that the air is being exhausted.
The processing after step 104 is executed. Step 104
Then, it is determined whether or not the supply valve 13FR is on. If the supply valve 13FR is off, it can be determined that the air is not discharged from the air chamber 3FR. Move to 106.

However, if it is determined in step 104 that the supply valve 13FR is ON, it can be determined that air is being exhausted from the air chamber 3FR. After counting up a counter RDC for measuring a certain time, step 10
Move to 6. In step 106, the supply valve 13
It is determined whether or not the FL is on. If the supply valve 13FL is off, it can be determined that no air is discharged from the air chamber 3FL, and therefore the process proceeds to the step 108 without executing the step 107. .

However, if it is determined in step 106 that the supply valve 13FL is ON, it can be determined that air is being exhausted from the air chamber 3FL. After counting up a counter LDC that measures a certain time,
Move to 8. Then, in step 108, it is determined whether or not the vehicle height has become equal to or higher than a predetermined vehicle height at which it can be determined that the jack-up has been performed.

Specifically, when at least one of the following equations (1) and (2) is satisfied, the determination in step 108 is made "YES". H _FR -H _C ≧ H _J (1) H _FL -H _C ≧ H _J (2) where H _C is the reference vehicle height and H _J is expected to occur when jack-up occurs. The difference between the reference vehicle height H _C and the actual vehicle height (for example, 40 mm).

If the determination in step 108 is "NO", it can be determined that the state is not abnormal as will be described later.
Return to However, the above processing is repeatedly executed, and if it is determined in step 108 that the vehicle height is equal to or higher than the predetermined vehicle height, the jack-up is performed, so that the air chambers 3FR and 3FL are in the exhaust state. Regardless, since it can be determined that the vehicle height is in an abnormal state of extremely rising, the process does not return to step 101, but proceeds to step 109 to recover the abnormally reduced internal pressure of the air chambers 3FR and 3FL. Execute.

In step 109, the normal vehicle height control executed in parallel with the processing of FIG. 2 is prohibited, and all the valves (cut valves 11FR to 11RL, supply valves 13FR, 13
FL, 13R and the exhaust valve 21) are turned off without supplying a command signal. Then, when the flag JUF is activated in step 110, the process proceeds to step 111,
The time RUC for forcibly supplying air to the air chamber 3FR and the time LUC for forcibly supplying air to the air chamber 3FL
Is calculated.

That is, at the time of jack-up, the air chambers 3FR, 3FR
The amount of air discharged from the FL is determined in steps 105 and 107.
From the time measured in the above, the change speed of the vehicle height when air is supplied from the compressor 5 is, for example, 0.89 mm /
sec, the speed of change of the vehicle height when discharging air is 1.
05mm / sec, and 1mm lower than before jack-up considering the undershoot when the jack is lowered.
If the vehicle height 0 mm higher is the target vehicle height, the time RUC, LU
C (sec) is obtained from the following equation (3) or (4).

RUC = (1.05 / 0.89) RDC + 10 / 0.89 (3) LUC = (1.05 / 0.89) LDC + 10 / 0.89 (4) To prevent, time RUC, LUC
Is set to the upper limit. For example, empty air chamber 3FR,
A time (for example, 81 sec) at which an internal pressure that can maintain the reference vehicle height when air is supplied to 3FL is set as an upper limit value, and even if a value longer than that is calculated, the upper limit value is set to RUC, LUC. And

Then, the routine proceeds to step 112, where air is forcibly supplied to the air chamber 3FR for a time RUC, and air is forcibly supplied to the air chamber 3FL for a time LUC. Then, since the internal pressures of the air chambers 3FR and 3FL have recovered to the internal pressures before the jack-up, even if the jack is lowered thereafter, the vehicle height does not decrease extremely.

When the forced supply of air is performed in step 112, the process returns to step 101 after all the valves are turned off. Since the flag FUG has been raised in step 110, the determination in step 101 is "YE
S ”, and proceeds to step 113. Step 11
In 3, it is determined whether or not the vehicle is stopped based on the vehicle speed detection value V. If it is determined that the vehicle is stopped, step 114 is executed.
And the vehicle heights H _FR and H _FL fall below a predetermined vehicle height (for example, a vehicle height 30 mm higher than the reference vehicle height) lower than the predetermined vehicle height used in the above-described step 108 in which jack-up is determined. Is determined.

That is, when the jack is lowered, the vehicle height that has been raised due to the jack-up returns to its original level. Therefore, when it is detected that the vehicle height has been lowered, it can be determined that the jack has been lowered. If not, the jack is naturally lowered, so the determination in step 114 is “YE
If “S” or if the determination in step 113 is “NO”, the process proceeds to step 115.

In step 115, all the valves are turned off, all the variables used in this processing are cleared, and the routine proceeds to step 116, where
The prohibition of the vehicle height control performed in step 9 is released. Thereafter, the process returns to step 101, and the above-described processing is repeatedly executed. On the other hand, if the determination in step 114 is “NO”,
Since it can be determined that the jack has not been dropped yet, the process returns to step 101 without clearing variables such as the flag JUF and prohibiting the vehicle height control.
This state is maintained until it is determined that the jack has been dropped.

As described above, according to the present embodiment, the air chamber 3
A situation where the vehicle height is abnormally rising due to jack-up regardless of the internal pressures of FR and 3FL is detected in step 108. In such a case, the air chambers 3FR and 3FL measured in steps 103 to 107 are exhausted. Since the air is forcibly supplied in step 112 according to the state of the state, the internal pressure of the air chambers 3FR and 3FL does not drop abnormally when the jack is lowered, and the bottom of the vehicle body and the jack frame Interference with the like can be avoided.

Moreover, in this embodiment, it is possible to detect a situation where the vehicle height is abnormally rising, regardless of the jack-up speed, etc., and to force the supply of air in accordance with the amount of discharged air. Therefore, abnormal lowering of the internal pressure of the air chambers 3FR and 3FL can be reliably prevented. Here, in the present embodiment, the vehicle height sensors 27, 29, and 30 correspond to vehicle height detecting means, and the vehicle height control processing executed in the compressor 5, the supply valves 13FR to 13R, the exhaust valve 21, and the controller 25 is performed. The processing of step 108 corresponds to the vehicle height determining means, the processing of steps 103 to 107 corresponds to the emission amount measuring means, and the processing of steps 111 and 112 corresponds to the forced supply means.

In the above-described embodiment, the air is exhausted from the air chambers 3FR, 3FL during jack-up based on the time RDC, LDC during which the exhaust valve 21 is on and the supply valves 13FR, 13FL are on. I'm looking for the amount of air,
The means for determining the amount of discharged air is not limited to this. For example, the volume and the internal pressure of the air chambers 3FR and 3FL at the start of the control and the air chamber when the vehicle height exceeds a predetermined vehicle height It is also possible to determine by comparing the volume and internal pressure of 3FR and 3FL.

In the above embodiment, the case where air is used as the fluid has been described. However, the present invention is not limited to this, and a gas or liquid other than air can be used.

[0043]

As described above, according to the present invention,
Detecting a situation where the vehicle height is raised abnormally due regardless example jacking up such an internal pressure of the fluid chamber, in such a case, supply a flow body the fluid chamber depending on the amount of the discharged fluid With the configuration, there is an effect that the abnormal decrease in the fluid chamber pressure is reliably prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing an outline of a process executed in a controller.

[Explanation of symbols]

 1FR ~ 1RL Suspension 3FR ~ 3RL Air chamber 5 Compressor 13FR ~ 13R Supply valve 21 Exhaust valve 25 Controller 27 Front right wheel height sensor 29 Front left wheel height sensor 31 Rear wheel height sensor 33 Vehicle speed sensor

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60G 17/015

Claims (1)

(57) [Claims] 1. A suspension including a fluid chamber capable of adjusting a vehicle height by supplying and discharging fluid, vehicle height detecting means for detecting vehicle height, and a vehicle height detected by the vehicle height detecting means and a target vehicle height. Vehicle height adjusting means for supplying a fluid to the fluid chamber based on the difference or discharging the fluid from the fluid chamber to adjust the vehicle height,
A vehicle height control device comprising: a vehicle height determination unit that determines whether the vehicle height is equal to or higher than a predetermined vehicle height that is higher than a target vehicle height region; and the vehicle height adjustment unit discharges fluid from the fluid chamber. The fluid discharged from the fluid chamber from the time when the vehicle height adjustment to be discharged is started until the vehicle height determining means determines that the vehicle height has risen and is equal to or higher than the predetermined vehicle height. a discharge amount measuring means for determining the amount of, the discharge amount measuring means of the vehicle height control device, characterized in that provided, and forced supply means for supplying a flow body to the fluid chamber in response to the measured value.