JPS60191803A - Suspension for car - Google Patents

Abstract

PURPOSE:To prevent the generation of hunting when the height of a car is adjusted beyond a desired car height range with preset width by controlling the car height immediately after it is adjusted so as to obtain a preset value within the lower or upper bound value that does not exceed the desired car height. CONSTITUTION:Normally, the movable contact Td of a switching circuit 5 is connected to a switching contact Ta and the height of a car is adjusted automatically according to a first reference value signal (a) that indicates the desired reference car height value X0 from a first reference signal generation circuit 2. In this case, the upper and lower bound values X3 and X2 that indicate the upper and lower bound signals (e) and (d) from upper and lower signal generation circuits 7 and 6 are X0+beta and X0-beta. In this state, for example, when an actual car speed signal (f) from a car height sensor 10 is set to (f)<(d), a solenoid 12 is excited by the output of a comparison circuit 8 and a shock absorber 24 is raised and adjusted. Simultaneously with this, the contact Td is switched into a contact Tb and the upper and lower bound values of the respective generation circuits 7 and 6 are corrected by a value alpha.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention includes a vehicle height adjustment section that automatically adjusts the vehicle height so that the height of the vehicle body relative to the axle is always maintained within a predetermined range. related to automobile suspension.

(Prior Art) In automobiles, a suspension is disposed between an axle and a vehicle body to reduce the transmission of impact from the road surface, which the axle receives, to the vehicle body.

Therefore, the height of the vehicle body relative to the axle (hereinafter referred to as vehicle height) is determined by the increase or decrease of the load on the vehicle body side that acts on the axle, or
It fluctuates due to the vertical movement of the axle depending on the road surface condition. Therefore, a vehicle height adjustment device has been proposed that automatically controls the vehicle height to return to a predetermined height when such a fluctuation occurs.

In such a vehicle height adjustment device, a target vehicle height range is usually set, and when the vehicle height fluctuates with a relatively small amplitude within this range, control for adjusting the vehicle height is not performed. Ru. This is because such small amplitude fluctuations in vehicle height always occur when a car is actually running, and control for adjusting the vehicle height must be performed even for such small amplitude fluctuations. In this case, the vehicle height is adjusted to repeatedly increase and decrease the vehicle height, and there is a risk that so-called hunting may occur, resulting in U7 failure.This is to avoid this. Such a target vehicle height range has a predetermined width with a predetermined upper limit value and lower limit value, and for example, the vehicle height when the vehicle is running stably on a flat road surface is approximately The vehicle height is set to be in the center of this range, and vehicle height adjustment is performed to maintain the vehicle height within this target vehicle height range. In a vehicle height adjustment device that controls such a vehicle height to maintain it within a target vehicle height range, the detected vehicle height value is compared with the upper and lower limits of the target vehicle height range, respectively, and the detected vehicle height value is determined. If the detected vehicle height value is larger than the upper limit value, the vehicle height is lowered, and if the detected vehicle height value is smaller than the lower limit value, the vehicle height is adjusted to raise the vehicle height. In vehicle height adjustment performed when the detected vehicle height value is smaller than the lower limit value, the vehicle height adjustment is canceled when the detected vehicle height value reaches the lower limit value. As a result, even if there is a relatively small change in the adjusted vehicle height, it will immediately exceed the lower limit and deviate from the target vehicle height range, and the vehicle height will be adjusted again, which is repeated and causes hunting. This is likely to occur. Therefore, when the vehicle height is adjusted, it is desirable that the adjusted vehicle height be at or near the center of the target range. Therefore, when adjusting the vehicle height, a vehicle height adjustment device has been proposed that cancels the adjustment after bringing the vehicle height to the center of the target vehicle height range or its vicinity. Japanese Unexamined Patent Publication No. 1983
There is a method as described in Japanese Patent No. 134311. In this vehicle height adjustment device, the vehicle height detector is capable of obtaining a vehicle height detection signal that can distinguish at least four vehicle height regions: "high", "medium high", "medium low", and "low". ,
To determine these vehicle height ranges, when the vehicle height becomes "high", a vehicle height lowering instruction signal is set, and this signal is held until the vehicle height becomes "medium/low", and the vehicle height lowering instruction signal is activated. While the vehicle is standing, the suspension drive system is energized to lower the vehicle height, and when the vehicle height becomes "low", a vehicle height raising instruction signal is activated, and the vehicle height becomes "medium/high". The suspension drive system is energized to raise the vehicle height while the vehicle height raising instruction signal is on. However, in this case, it is necessary to perform control operations based on accurate judgment of four or more vehicle height regions, which tends to complicate the configuration of the vehicle height detector and the entire device. There is an inconvenience.

(Object of the Invention) In view of the above, the present invention has a relatively simple configuration, and has the following features:
When vehicle height adjustment is performed when the vehicle height falls outside the target vehicle height range, which has a predetermined upper and lower limit value and a predetermined width,
Equipped with a vehicle height adjustment function that automatically controls the vehicle height immediately after adjustment to a predetermined value that is within the lower limit or upper limit of the target vehicle height range. The purpose of the company is to provide suspensions for automobiles with improved performance.

(Structure of the Invention) An automobile suspension according to the present invention selectively takes at least a first lower limit value and a second lower limit value higher than the first lower limit value, and also has at least a first upper limit value and a second lower limit value higher than the first lower limit value. target vehicle height setting means for selectively setting a second upper limit value lower than the first upper limit value to set a target vehicle height range; vehicle height detection means for obtaining an actual vehicle height value; Alternatively, first comparison means obtains the first control signal by comparing the second lower limit value and the actual vehicle height value, and the first or second upper limit value taken by the target vehicle height setting means and the actual vehicle height value. a second comparing means for comparing to obtain a second control signal;
increasing the vehicle height based on the above-mentioned first control signal;
The vehicle height adjusting means operates to reduce the vehicle height in response to the second control signal, and the target vehicle height setting means is set to the target vehicle height setting means when the vehicle height adjusting means is not activated. The target vehicle height range is set by taking the first lower limit value and the first upper limit value, and the target vehicle height range is set by taking the second lower limit value when the first control signal of the vehicle height adjustment means is activated. Furthermore, the second control signal of the vehicle height adjusting means is configured to take the second upper limit value when activated to set the target vehicle height range.

By doing this, when the vehicle height falls outside the target vehicle height range set by the first upper limit value and the first lower limit value, the vehicle height is adjusted, and as a result of the adjustment, the vehicle height becomes the first The vehicle height adjustment is canceled because the vehicle height is assumed to be a value that is far from both the first upper limit and the first lower limit within the 1" standard vehicle height range that is set with the upper limit and the first lower limit. This prevents the hunting phenomenon from occurring.

(Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an automobile suspension according to the present invention. Here, a terminal 1 into which information about the target reference vehicle height value X0 is input is provided, and this is connected to the respective input terminals of the first, second and third reference value signal generation circuits 2.3 and 4. . In the first reference value signal generation circuit 2, the target reference vehicle height value X0 is not reached and the first reference value signal a is obtained.
The reference value signal generating circuit 3 generates the target reference vehicle height value X. Standard value X+ (X+ = Xo +α) which is obtained by adding correction value α to
A second reference value signal is obtained, and a third reference value signal is obtained.
The reference value signal generating circuit 4 generates the target reference vehicle height value X. The reference value X, '(X,'' = Xo - α, which is obtained by subtracting the correction value α from
), the third reference value signal C is obtained.

Such first. Second and third reference value signal generation circuit 2.3
and 4 are respectively connected to changeover contacts Ta, 'I''b and Tc of a switch circuit 5 forming a selection means.A movable contact Td of the switch circuit 5 is connected to a lower limit signal generation circuit 6. and the respective input terminals of the lower limit signal generation circuit 7.

The lower limit value signal generation circuit 6 generates the target reference vehicle height value X.

A lower limit signal d is obtained which generates the lower limit value X2 by subtracting a certain value β from either of the reference values X1 and XIo, and the upper limit signal generation circuit 7 obtains the target reference vehicle height value X0 and the reference value An upper limit signal e is obtained which generates an upper limit value X3 which is obtained by adding a certain value β to either X1 or X1'. A target vehicle height range is set using these lower limit value X2 and upper limit value X3. The output end of the lower limit signal generation circuit 6 is connected to one output end of a comparison circuit 8, and the output of the upper limit signal generation circuit 7 is connected to one output end of another comparison circuit 9. ing.

Also, a vehicle height sensor 1 detects the vehicle height, obtains an actual vehicle height value corresponding to the detected vehicle height, and sends out an actual vehicle height signal f without detecting this value.
0 is provided, and its output terminal is connected to the other input terminal of each of comparator circuits 8 and 9. In the comparator circuit 8, a level comparison is performed between the actual vehicle height signal f, which indicates the actual vehicle height value from the vehicle height sensor 10, and the lower limit value signal d, which does not exceed the lower limit value X2, and the level of the actual vehicle height signal f is compared with the lower limit value signal d. The control signal g from its output terminal is smaller than the level g
is assumed to be at a high level. On the other hand 1. In the comparator circuit 9, a level comparison is performed between the actual vehicle height signal f and the upper limit signal e that determines the upper limit value X3, and only when the level of the actual vehicle height signal f is higher than the level of the upper limit signal e. The control signal from the output terminal is assumed to be at a high level.

The output end of the comparison circuit 8 is connected to the solenoid 12 via the amplifier circuit 11 and also to one control end of the switch circuit 5. On the other hand, the output terminal of the comparison circuit 9 is
It is connected to the solenoid 14 via the amplifier circuit 13, and also to the other control end of the switch circuit 5.

In the switch circuit 5, the movable contact Td is normally the switching contact Ta.
However, when the control signal g from the comparison circuit 8 takes a high level, the movable contact Td takes a state connected to the switching contact Tb, and the control signal g from the comparison circuit 9 takes a high level. In this case, the movable contact Td is connected to the switching contact Tc.

The solenoids 12 and 14 form part of a drive means for driving the vehicle height adjustment means. In this drive means,
A hydraulic pump 2o and a motor 21 for driving the hydraulic pump 2o are provided, and a pressure oil pipe from the hydraulic pump 2o is connected to a switching valve 22, which is connected to the solenoids 12 and 1.
4. The pressure oil pipe of the switching valve 22 is connected to a 7-cumulator 23 and a shock absorber 24 which also serves as vehicle height adjustment means.

The shock absorber 24 includes a piston 25 whose tip end is attached to a vehicle body 26, and a cylinder 27 whose tip end is attached to a wheel support part 28. Although not specifically shown here, the vehicle height sensor 1° described above is installed between the vehicle body 26 and a portion related to the axle 29, and is configured to adjust the height of the vehicle body 26 with respect to the axle 29. The actual vehicle height signal f is generated by detecting the vehicle height.

In such a vehicle height adjusting means and driving means, when the solenoid 12 is excited by the control signal g having a high level, the pressure oil from the hydraulic pump 20 is transferred to the shock absorber via the switching valve 22. 24 side, and this pressure oil flows through the pressure oil passage hole (
(not shown) to the cylinder 27. This pushes up the piston 25, and as a result, the vehicle height increases at a predetermined speed. In this case, the pressure oil acts on the piston 25 with a constant pressure due to the action of the accumulator 23. On the other hand, when the solenoid 14 is energized by a control signal that takes a high level, the pressure oil in the cylinder 27 of the shock absorber 24 passes through the pressure oil passage hole of the piston 25, and furthermore, the switching A state is taken in which the liquid is discharged to the discharge pipe 30 side via the valve 22. As a result, the piston 25 is pushed down by the weight of the vehicle body 26, and as a result, the vehicle height is lowered at a predetermined speed. Furthermore, when both the control signals g and h are assumed to be at a low level and both the solenoids 12 and 14 are not energized, the switching valve 22 is closed and the pressure oil in the cylinder 27 of the shock absorber 24 is is maintained without being changed, and as a result, the vehicle height at that time is maintained. Although not shown here,
A shock absorber 24, which also serves as vehicle height adjusting means, is arranged on the left or right side of the vehicle body, and is similarly driven by the same driving means.

Next, control of an example of the suspension of an automobile according to the present invention configured as described above will be described.

Under normal conditions, that is, when vehicle height adjustment is not being performed, the movable contact Td of the switch circuit 5 is connected to the switching contact Ta, and in this case, the lower limit value signal generation circuit 6 and the upper limit value signal generation circuit 7 is supplied with the first reference value signal a from the first reference value signal generation circuit 2, and is supplied with the lower limit value signal d from the lower limit value signal generation circuit 6 as shown in FIG. 2A. Lower limit (direct X2 is X.-β), and the lower limit
is X. +β becomes. Therefore, in this case, the lower limit value X. −β
The target vehicle height range is set using the upper limit value X0+β.

Here, as shown in FIG. 2A, when the level of the actual vehicle height signal f becomes smaller than the level of the lower limit value signal d, as shown in FIG.
As shown in FIG. 2, the control signal g from the comparator circuit 8 changes from a low level to a high level. As a result, the solenoid 12 is energized, and as a result, the shock absorber 24 operates to increase the vehicle height, thereby adjusting the vehicle height. At the same time, the movable contact Td of the switch circuit 5 moves as shown by the broken line in FIG.
As a result, the lower limit value signal generation circuit 6 and the upper limit value signal generation circuit 7 have the second
A second reference value signal from the reference value signal generation circuit 3 is supplied. As a result, the lower limit value X2 of the lower limit value signal d from the lower limit value signal generation circuit 6 is X, -β=X0+
α−β, and the upper limit value X3 at which the upper limit signal e from the upper limit signal generation circuit 7 is generated is Xl + β = Xo +
It becomes α+β. Therefore, in this case, the lower limit x0+α−β
The target vehicle height range is set by the upper limit value X0+α+β, and as shown in FIG. 2A, the level of the lower limit signal d increases by the correction value α, and the level of the upper limit signal e also increases by the correction value α. only rises.

In this example, the correction value α is selected to be the same value as the constant value β, so that the value at which the lower limit value signal d is generated is the same as the target reference vehicle height value X0. When the vehicle height increases due to vehicle height adjustment and the level of the actual vehicle height signal f reaches a level indicating the target reference vehicle height value X0 of the lower limit value signal d, the control signal g from the comparison circuit 8 takes a high level. It will change from to something that takes a low level. As a result, the solenoid 12 is de-energized (and the vehicle height adjustment by the shock absorber 24 is completed. At this time, the vehicle height is approximately at the lower limit value
. −β and the upper limit X0+β is the center target reference vehicle height value X of the target vehicle height range. It is said that

Then, the control signal g from the comparator circuit 8 becomes low level again, so that the movable contact T of the switch circuit 5
d is again connected to the switching contact Ta, and as a result, the lower limit value X2 and the upper limit value X3, which are the lower limit value signal d and the upper limit value signal e, return to Xo-β and X0+β, respectively, and with these, the target vehicle height is determined again. The range is set.

Next, when the level of the actual vehicle height signal f becomes higher than the level of the upper limit signal e, the control signal from the comparison circuit 9 changes from a low level to a high level,
As a result, the solenoid 14 is energized, and as a result, the shock absorber 24 operates to reduce the vehicle height, and the vehicle height is adjusted. At the same time, the switch circuit 5
The movable contact Td is connected to the switching contact Tc, and as a result, the lower limit value signal generation circuit 6 and the upper limit value signal generation circuit 7 receive the third reference from the third reference value signal generation circuit 4. A value signal C is provided. As a result, the lower limit value X2 of the lower limit value signal d from the lower limit value signal generation circuit 6 is:
x,l −β=X o−α−β, and the lower limit value X3 at which the upper limit signal e occurs is X,”+β=X,−
It becomes α+β. Therefore, in this case, the lower limit value X. −α−β
and upper limit value X. The target vehicle height range is set by -α+β, the level of the lower limit signal d is lowered by the correction value α, and the level of the upper limit signal e is also lowered by the correction value α.

In this example, the correction value α is selected to be the same value as the constant value β, and therefore, the value at which the upper limit signal e is generated is the target reference vehicle height value X. is the same as Then, the vehicle height is reduced by the vehicle height adjustment, and the level of the actual vehicle height signal f becomes the target standard vehicle height value X of the upper limit signal e. When the signal reaches a level without indicating a high level, the control signal from the comparator circuit 9 changes from a high level to a low level. As a result, the solenoid 14 is no longer energized, and the vehicle height adjustment by the shock absorber 24 is completed. At this time, the vehicle height is approximately the lower limit value
Target reference vehicle height value X at the center of the target vehicle height range set by 0−β and upper limit X0+β. It is said that

Then, the control signal from the comparison circuit 9 becomes low level again, so that the movable contact T of the switch circuit 5
d is again connected to the switching contact Ta, and as a result, the lower limit value X2 and the upper limit value X3, which are the lower limit value signal d and the upper limit value signal e, return to Xo-β and X0+β, respectively, and with these, the target vehicle height is determined again. The range is set.

Note that although the correction value α and the constant value β are assumed to be the same here, they may be different from each other, and may be subtracted and added in the second and third reference value signal generation circuits 3 and 4. The correction values may not be selected to be the same value.

FIG. 3 shows another example of an automobile suspension according to the present invention. In the example shown in FIG. 1, both the upper limit and lower limit that define the target vehicle height range during the vehicle height adjustment period are raised or lowered compared to the non-vehicle height adjustment period. However, in this example, only one of the upper limit value and the lower limit value is raised or lowered during the vehicle height adjustment period. This example has parts corresponding to the parts of the example shown in FIG. 1, and these parts are given the same reference numerals as those in FIG. 1, and the explanation thereof will be omitted.

In this example, the terminal 1 to which information about the target standard vehicle height value X0 is input is connected to the first and second lower limit signal generation circuits 40.
and 41, and also connected to the input terminals of the first and second
It is also connected to the input terminals of upper limit value signal generation circuits 42 and 43, respectively. In the first lower limit signal generation circuit 40,
The first lower limit value X is obtained by subtracting the value β1 from the target standard vehicle height value X. -β1 is obtained, and the second lower limit signal generation circuit 41 outputs the target reference vehicle height value X.

A second lower limit value X obtained by subtracting the value β2 (β1 > β2) from -β2 is not detected and the lower limit signal j is obtained. Further, the first upper limit value X is obtained by adding the value β to the target reference vehicle height value X0 from the first upper limit value signal generation circuit 42.

+β3 is obtained, and the second upper limit signal generation circuit 43 outputs the value β4 to the target reference vehicle height X0.
A second upper limit signal l is obtained, which is the second upper limit value Xo+β, which is the sum of (β, >β, selected).

Such first and second lower limit signal generation circuits 40 and 41
The respective output terminals of the switch circuit 44 are connected to the switching contacts T e
and Tf, respectively. Further, the output terminals of the first and second upper limit signal generation circuits 42 and 43 are connected to the switching contacts Th and Ti of the switch circuit 45, respectively. The movable contact Tg of the switch circuit 44 is connected to one input terminal of the comparator circuit 8, and the movable contact Tj of the switch circuit 45 is connected to one input terminal of the comparator circuit 9. The output terminal of the vehicle height sensor 10 is connected to the other input terminals of the comparison circuits 8 and 9, and in the comparison circuit 8, the actual vehicle height signal f from the vehicle height sensor IO and the lower limit value signal i or j are connected. Only when the level of the actual vehicle height signal f is smaller than the level of the lower limit value signal i or j, the control signal g from the output terminal is assumed to take a high level. In the circuit 9, a level comparison is made between the actual vehicle height signal f and the upper limit signal or l, so that the level of the actual vehicle height signal f becomes the upper limit signal or! The control signal from the output terminal assumes a high level only when the voltage is larger than that.

The output end of the comparison circuit 8 is connected to the solenoid 12 via the amplifier circuit 11 and also to the control end of the switch circuit 44 . The output end of one comparison circuit 9 is connected to the solenoid 14 via the amplifier circuit 13 and also connected to the control end of the switch circuit 45. The switch circuit 44 normally takes a state in which the movable contact Tg is connected to the switching contact Te, as shown by the solid line in FIG. 3, but when the control signal g from the comparator circuit 8 takes a high level, The movable contact Tg is assumed to be connected to the switching contact Tf. Further, the switch circuit 45 also normally takes a state in which the movable contact Tj is connected to the switching contact Th, but when the control signal from the comparator circuit 9 takes a high level, the movable contact Tj is connected to the switching contact Ti. It is assumed that the state of Others, solenoids 12 and 14
The switching valve 22 driven by the vehicle, the shock absorber 24 serving as vehicle height adjusting means, and the like are constructed in the same manner as in the example shown in FIG.

Next, the operation of the example of the automobile suspension according to the present invention shown in FIG. 3 having the above-described structure will be described.

When the vehicle height is not adjusted, the movable contact Tg of the switch circuit 44 is connected to the changeover contact Te, and the movable contact Tj of the switch circuit 45 is connected to the changeover contact Th, as shown in FIG. As shown in FIG. 4A, one input terminal of the comparator circuit 8 receives the first lower limit value X. -β1 is supplied with a lower limit signal i, and one input terminal of the comparator circuit 9 is supplied with a first upper limit signal i.
X.

An upper limit signal k is supplied which increases +β3. Therefore,
In this case, the lower limit value x0-β1 and the upper limit value X. The target vehicle height range is set with +β3.

Here, when the level of the actual vehicle height signal f from the vehicle height sensor 10 becomes smaller than the level of the lower limit value signal i, the control signal g from the comparator circuit 8 changes to a low level as shown in FIG. 4B. It changes from one that takes a high level to one that takes a high level. As a result, the solenoid 12 is energized, and as a result, the shock absorber 24 operates to increase the vehicle height.
The vehicle height is adjusted.

At the same time, the movable contact Tg of the switch circuit 44 becomes connected to the switching contact Tf, as shown by the broken line in FIG. Therefore, one input terminal of the comparison circuit 8 receives the second signal from the second lower limit signal generation circuit 41.
Since the lower limit value X0-β2 is not reached, the lower limit signal j is supplied. As a result, as shown in FIG. 4A, the lower limit of the target vehicle height range becomes When the vehicle height increases and the level of the actual vehicle height signal f reaches the level of the lower limit signal j, the control signal g from the comparison port B8 changes from a high level to a low level. As a result, the solenoid 12 is no longer energized, and the vehicle height adjustment is completed.At this time, the vehicle height is set to the second lower limit X0 within the target vehicle height range, which is set approximately at the lower limit X0-β1 and the upper limit X0+β. -β2 level.

Then, as the control signal g from the comparator circuit 8 becomes low level again, the movable contact Tg of the switch circuit 44 is connected to the switching contact Te again, and as a result, the lower limit of the target vehicle height range is , is returned to the original first lower limit value X0-β.

Next, the level of the actual vehicle height signal f from the vehicle height sensor 10 is
When the level exceeds the upper limit signal, the control signal from the comparison circuit 9 changes from a low level to a high level, which energizes the solenoid 14, and as a result, Shock absorber 2
4 operates to reduce the vehicle height, and the vehicle height is adjusted.

At the same time, the movable contact Tj of the switch circuit 45 becomes connected to the switching contact Ti. Therefore, one input terminal of the comparison circuit 9 is connected to the second upper limit signal generation circuit 43.
An upper limit value signal β is supplied which generates a second upper limit value X0+β from . As a result, the upper limit of the target vehicle height range is
. +β4, and is in a state where it has fallen by β3-β4. Then, when the vehicle height is reduced by the vehicle height adjustment by the shock absorber 24 and the level of the actual vehicle height signal f reaches the level of the upper limit value signal β, the control signal from the comparison circuit 9 takes a high level. It changes to something that takes a lower level. As a result, the solenoid 14 is no longer excited, and the vehicle height adjustment is completed.

At this time, the vehicle height is approximately the lower limit value X. −β1 and upper limit X0+
The second upper limit (
l￥! It is considered to be at the level of X0+β4.

Then, when the control signal from the comparator circuit 9 takes a low level again, the movable contact Tj of the switch circuit 45 is connected to the switching contact Th again, and as a result, the upper limit value of the target vehicle height range returns to the original level. 1 is returned to the upper limit value X0+β3.

As described above, in any case, when the vehicle height is adjusted, the adjusted vehicle height takes a value sufficiently distant from the lower and upper limits of the normal target vehicle height range. After that, the vehicle height adjustment will be canceled.

(Effects of the Invention) As is clear from the above description, according to the automobile suspension according to the present invention, the vehicle height can be maintained within a predetermined width with a lower limit value and an upper limit value determined based on a relatively simple configuration. If the vehicle height is outside the target vehicle height range, the vehicle height is adjusted.
The vehicle height immediately after adjustment can be made to take a value in the center of the target vehicle height range, for example, sufficiently distant from both the lower limit and the upper limit within the target vehicle height range. Therefore, even if the vehicle height changes immediately after the vehicle height adjustment is canceled, the probability that the vehicle height will remain within the target vehicle height range is extremely high, and the occurrence of hunting can be effectively avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an example of an automobile suspension according to the present invention, FIG. 2 is a waveform diagram used to explain the operation of the example shown in FIG. 1, and FIG. A schematic configuration diagram showing another example of the suspension, FIG.
FIG. 3 is a waveform diagram used to explain the operation of the example shown in the figure. In the figure, 2 is a first reference value signal generation circuit, 3 is a second reference value signal generation circuit, 4 is a third reference value signal generation circuit, 5,
44 and 45 are switch circuits, 6 is a lower limit value signal generation circuit, 7 is an upper limit value signal generation circuit, 8 and 9 are comparison circuits, 10
12 is a vehicle height sensor, 12 and 14 are solenoids, 22 is a switching valve, 24 is a shock absorber, 140 is a first lower limit value signal generation circuit, 41 is a second lower limit value signal generation circuit, 42
43 is a first upper limit signal generation circuit, and 43 is a second upper limit signal generation circuit.

Claims (1)

[Claims] Selectively take at least a first lower limit value and a second lower limit value higher than the first lower limit value, and also selectively take at least a first upper limit value and a second upper limit value lower than the first upper limit value. target vehicle height setting means for setting a target vehicle height range for the vehicle;
vehicle height detection means for obtaining an actual vehicle height value; and first comparison means for obtaining a first control signal by comparing the actual vehicle height value with the first or second lower limit value taken by the target vehicle height setting means. and a second comparing means for obtaining a second control signal by comparing the first or second upper limit value taken by the target vehicle height setting means and the actual vehicle height value, and the first control signal. and vehicle height adjustment means that operates to increase the vehicle height based on the vehicle height and decrease the vehicle height based on the second control signal, and the target vehicle height setting means operates to increase the vehicle height based on the vehicle height. When the adjustment means is not activated, the first lower limit value and the first upper limit value are used to set the target vehicle height range, and when the adjustment means is activated, the first lower limit value and the first upper limit value are used to set the target vehicle height range. A lower limit value is taken to set a target vehicle height range, and when the vehicle height adjustment means is activated based on the second control signal, the target vehicle height range is set by taking the second upper limit value. An automobile suspension characterized by being controlled as follows.