JP3086935B2 - Height adjustment 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 adjusting device provided in an automobile.

[0002]

2. Description of the Related Art As an example of a conventional vehicle height adjusting device, a vehicle height adjusting device is interposed between a vehicle body and each wheel side in order to control an average vehicle height (a vehicle height excluding a vehicle height change due to vibration). A cylinder that adjusts the vehicle height by supplying and discharging oil, a supply and discharge mechanism that supplies and discharges oil to and from the cylinder, a vehicle height sensor that detects the vehicle height from the relative displacement between the vehicle body and the wheels, There is a configuration having a controller that operates a supply / discharge mechanism based on a detection signal of a sensor to expand and contract a cylinder.
In this vehicle height adjusting device, among the eight sampled vehicle height values, if there are five times higher than the preset reference value, it is determined that the average vehicle height is high. Judge as average vehicle height trim (neutral state)
If there are five times lower than the reference value, it is determined that the average vehicle height is low, and the vehicle height is adjusted according to the determination result.

[0003]

By the way, in the above-mentioned vehicle height adjusting device, a vehicle height signal used for determination processing with a reference value in order to perform an oil supply / discharge instruction and a process of stopping the oil supply / discharge. Is used. For this reason,
If the sampling interval of the vehicle height signal is shortened (to improve the followability of the vehicle height sensor), oil supply and drainage will be performed due to vibrations caused by changes in road surface conditions and body movements (rolls, dives, squats). The control signal is frequently output, and there is a problem that erroneous determination and supply / discharge oil chattering are likely to occur. Conversely, if the sampling cycle is lengthened (follows the vehicle height sensor with a delay), there is a problem that hunting is likely to occur due to excessive oil supply and drainage when oil supply and drainage is performed. Was.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle height adjusting device capable of suppressing occurrence of erroneous determination and hunting.

[0005]

According to a first aspect of the present invention, there is provided a cylinder which is interposed between a vehicle body and each wheel side and which expands and contracts by supplying and discharging fluid. A supply / discharge mechanism for supplying / discharging fluid, expansion / contraction detection means for detecting an amount of expansion / contraction of the cylinder and outputting an expansion / contraction signal, and comparing the level of the expansion / contraction signal with a preset reference expansion / contraction range, A step signal for outputting a positive, negative, or zero step signal when the signal level is in an area exceeding the reference expansion / contraction range, in a region less than the reference expansion / contraction range, or in the reference expansion / contraction range, respectively. A generating circuit, and a long time constant and a short time constant, respectively, and performing a signal processing according to the time constant on the step signal to output a long time constant vehicle height pseudo signal and a short time constant vehicle height pseudo signal, respectively. First The second low-pass filter compares the level of the long time constant vehicle height pseudo signal with a preset supply / discharge threshold value and outputs a supply / discharge instruction signal for causing the supply / discharge mechanism to supply / discharge to / from the cylinder according to the comparison result. It outputs a short time constant vehicle height pseudo signal level and compares it with a preset supply / discharge stop threshold, and outputs a supply / discharge stop instruction signal for stopping the supply / discharge to the cylinder in accordance with the comparison result. And a supply / discharge instruction circuit.

According to a second aspect of the present invention, there is provided a cylinder interposed between a vehicle body and each wheel side, which expands and contracts by supplying and discharging fluid, and supplies and discharges fluid to and from the cylinder. A supply / discharge mechanism, expansion / contraction amount detection means for detecting the amount of expansion / contraction of the cylinder and outputting an expansion / contraction signal, and comparing the level of the expansion / contraction signal with a preset reference expansion / contraction range, If it is in the area exceeding the expansion / contraction range, if it is in the area below the reference expansion / contraction range,
A step signal generating circuit that outputs a positive, negative, or zero step signal when the reference signal is within the reference expansion / contraction range; an integration circuit that performs an integration process on the step signal; A small and a large gain circuit for amplifying a signal from the integration circuit to generate a small gain integration step signal and a large gain integration step signal, and the level of the signal from the small and large gain circuits is predetermined. A saturation processing circuit for maintaining and outputting the level until the next supply / discharge processing when the magnitude of the signal reaches the magnitude of a small gain integration step signal from the saturation processing circuit; The controller outputs a supply / discharge instruction signal for causing the supply / discharge mechanism to supply / discharge the cylinder, and sets the level of the large gain integration step signal from the saturation processing circuit to a preset supply / discharge. Characterized by providing a feeding and discharging instruction circuit for outputting a supply and discharge stop instruction signal for stopping the supply and discharge with respect to the cylinder to supply and discharge mechanism as compared to the stop threshold.

[0007]

According to a first aspect of the present invention, a step signal generated based on an expansion signal is processed by first and second low-pass filters in accordance with respective time constants, and a fluid is generated based on a signal obtained by this processing. Supply / discharge and stop. According to a second aspect of the present invention, the step signal generated based on the expansion and contraction signal is processed by the integration circuit and the small and large gain circuits,
Supply and discharge of the fluid and its suspension are performed based on the signal obtained by this processing.

[0008]

FIG. 1 shows a vehicle height adjusting device according to an embodiment of the present invention.
7 will be described with reference to FIG. First, FIGS. 1 to 4
A first embodiment of the present invention will be described based on FIG. In the figure, a total of four cylinders 1 (only one corresponding to one wheel is shown in the figure) are interposed between a vehicle body (not shown) and each wheel (not shown). By supplying and discharging an oil liquid (fluid) to and from the cylinder 1, the vehicle height can be adjusted by expanding and contracting.

A pump 3 is connected to the cylinder 1 via an oil passage 2. The pump 3 is driven by the electric motor 4 to suck and compress the oil liquid stored in the reservoir tank 5 through the suction filter 6 and discharge it to the cylinder 1 side as pressure oil. A supply / drain oil valve 7 and an orifice 8 are provided in this order in an oil passage 2 connecting the pump 3 and the cylinder 1.

The orifice 8 and the cylinder 1 in the oil passage 2
And the orifice 9 and the gas spring 10
Is provided. When the cylinder 1 expands and contracts, the gas spring 10 absorbs the force of the oil liquid for the stroke,
Since a damping force is generated by the orifice 9, vibration of the vehicle body is suppressed.

First and second branch oil passages 11 and 12 are connected to a portion of the oil passage 2 connecting the pump 3 and the supply / discharge oil valve 7. The other end of the first branch oil passage 11 extends to the reservoir tank 5, and an electromagnetic switching relief valve 13 is provided in the middle. This electromagnetic switching type relief valve 13 is opened (ON).
In this state, the oil liquid is discharged to the reservoir tank 5 through the first branch oil passage 2.

At the other end of the second branch oil passage 12, the cylinder 1, the oil supply / discharge valve 7, the gas spring 10 and the like constructed as described above are provided with the other three wheels as shown in FIG. Connected corresponding to. The illustration of the equipment provided at the other end of the second branch oil passage 12 is omitted.

In the present embodiment, the electric motor 4, the pump 3, the oil supply / discharge valve 7 (including those corresponding to the other three wheels, not shown), and the electromagnetic switching type relief valve 13 configured as described above are used. The supply / discharge mechanism 14 is configured.

A vehicle height sensor (expansion and contraction amount detecting means) 15 is interposed between the vehicle body and each wheel (wheel), and detects the vehicle height (ie, the amount of expansion and contraction of the cylinder 1) and outputs a vehicle height signal ( The signal is output as an expansion / contraction signal A.

Connected to a vehicle height sensor 15, a first
A step signal generating circuit 21 which forms a controller 20 together with the second low-pass filters 16 and 17, a memory 18, and a supply / discharge instruction circuit 19 is provided.

The step signal generation circuit 21 compares the level of the vehicle height signal A with a preset reference vehicle height range (reference expansion / contraction range) B, and the level of the vehicle height signal A exceeds the reference vehicle height range B. When the vehicle is in the region, when the vehicle is in the region less than the reference vehicle height range B, and when the vehicle is within the reference expansion / contraction range, a positive, negative, and zero step signal C is output. In this embodiment, when the level of the vehicle height signal A is in an area exceeding the reference vehicle height range B, the absolute value is 100 and the value is +100.
Step signal C having an absolute value of 100 and a value of -100 when the signal is in an area smaller than the reference vehicle height range B, and an absolute value of 0 and a value of 0 when the signal is within the reference expansion / contraction range. The step signal C is output.

The first and second low-pass filters 16, 17 are:
Each has a long time constant and a step signal C from the step signal generation circuit 21 and performs signal processing in accordance with the time constant to obtain a long time constant vehicle height pseudo signal h.
_l, generates a short time constant vehicle height pseudo signal h _S outputs this. The step signal generating circuit 21 and the second low-pass filter 17 (short time constant) constitute a first signal generating means, and the step signal generating circuit 21, the first low-pass filter 17 (long time constant) and Constitute the second signal generating means.

The memory 18 stores a preset oil supply threshold I, an oil discharge threshold K (supply / discharge threshold), an oil supply stop threshold J, and an oil discharge stop threshold L (supply / discharge stop threshold). value)
Is stored. In this case, -100 <I <J <0, 0 <
It is set so that L <K <+100. further,
The memory 18 stores the reference vehicle height range B used for comparison with the level of the vehicle height signal A.

The supply and discharge instruction circuit 19, the level refueling threshold I constant vehicle height pseudo signal h _l time length, carried feed and discharge with respect to the cylinder 1 in the supply and discharge mechanism 14 as compared to the oil discharge threshold value K (Hereinafter, a signal output for refueling is referred to as a refueling instruction signal D, and a signal output for refueling is referred to as an oil discharging instruction signal E). and Mijikatoki constant vehicle height pseudo signal h _S level refueling stop threshold J, the supply and discharge stop instruction signal for stopping the supply and discharge with respect to the cylinder 1 in the supply and discharge mechanism 14 as compared with the drain oil abort threshold L (Hereinafter, what is output for refueling will be referred to as refueling stop
The signal output in response to the drainage is referred to as a drainage stop instruction signal G. ) And output this.

Here, the signal processing contents of the controller 20, which is composed of the first and second low-pass filters 16, 17, a memory 18, a supply / discharge instruction circuit 19, and a step signal generation circuit 21, are shown in FIG. A description will be given based on FIG.

First, initialization is performed by turning on a power switch (not shown) (step S1), and it is determined whether or not the control cycle has elapsed (step S2). If the determination is NO, the determination in step S2 is performed again.

In step S3, a step signal C is inputted from the step signal generating circuit 21, and in a succeeding step S4, a vehicle height determination subroutine is executed. Based on the result of the determination, oil supply / discharge processing is performed in step S5, and vehicle height adjustment is performed.

The vehicle height determination subroutine will be described with reference to FIG. Step S6, when each in S7 length constant vehicle height pseudo signal h _l, generates a constant vehicle height pseudo signal h _S when short. Subsequent to step S7, it is determined whether or not the level of the long time constant vehicle height pseudo signal _hl is smaller than 0 (step S8). If the result is YES, the process proceeds to step S9 (refueling determination step) to determine NO. In this case, the process proceeds to step S13 (oil drainage determination step).

In step S9, the long time constant vehicle height pseudo signal h _l
It is determined whether or not the level is smaller than the refueling threshold value I,
If YES is determined, a refueling instruction signal D is output to the refueling mechanism 14 to refuel the cylinder 1 (step S10).
After this process, the process returns to the main routine to perform the process.

[0025] If it is determined NO in step S9, the short when the level of the constant vehicle height pseudo signal h _S is determined whether larger refueling stop threshold J (step S11), and the oil supply stop instruction signal and determines that YES F Is output, thereby stopping the refueling of the cylinder 1 (step S12).
After that, the process returns to the main routine.

If NO is determined in the step S11, the process returns to the main routine. As described above, the refueling of the cylinder 1 and its suspension are performed by the processing of steps S8 to S12.

The following steps S13 to S1
6 performs the draining of oil from the cylinder 1 and the suspension control thereof, in contrast to the processing of steps S8 to S12 described above for the supply of oil to the cylinder 1 and the suspension control thereof.

In step S13, the long time constant vehicle height pseudo signal h
_It is determined whether or not the level _l is greater than the oil discharge threshold value K. If the determination is YES, an oil discharge instruction signal E is output to the supply / discharge mechanism 14 to perform oil discharge from the cylinder 1, and after this processing, The process returns to the main routine.

[0029] If it is determined NO in step S13, short-time level constant vehicle height pseudo signal h _S is determined whether the oil discharge stop threshold smaller than L (step S15), and drain oil cancellation instruction when it is determined that YES A signal G is output, thereby stopping the drainage of oil from the cylinder 1 (step S16).
After that, the process returns to the main routine.

If NO is determined in the step S15, the process returns to the main routine. As described above, the oil discharge from the cylinder 1 and its suspension are performed by the processing of steps S13 to S16.

The operation of the vehicle height adjusting device constructed as described above will be described with reference to FIGS. The height of the vehicle decreases due to a person getting on the vehicle body or carrying luggage, and the level of the vehicle height signal A falls below the reference vehicle height range B (time t ₀ ).
Then, the step signal generating circuit 21 outputs a step signal C having a value of -100. Then, the first and second low-pass filters 16 and 17 generate a long time constant vehicle height pseudo signal h _l and a short time constant vehicle height pseudo signal h _S (steps S6 and S7) and supply them to the supply / discharge instruction circuit. Output to 19.

[0032] The ratio in this case, long time constant vehicle height pseudo signal h _l, short time any constant vehicle height pseudo signal h _S is made to saturate the value of -100, the time required for saturation is the former latter It has become long. Moreover, the constant vehicle height pseudo signal h _l when the length, by the reduction ratio is less than the rate of decrease in the short time constant vehicle height pseudo signal h _S, the level is the time to reach a predetermined value short many such in comparison with the time constant vehicle height pseudo signal h _S.

When the level of the long time constant vehicle height pseudo signal _hl reaches the refueling threshold value I (time t ₁ ) (YES in step S9)
), The refueling instruction signal D is output to the refueling / discharging mechanism 14 (step S), the electric motor 4 is turned on, the electromagnetic switching type relief valve 13 is closed (off), and the refueling / discharging valve 7 is opened. (on)
Thus, oil is supplied to the cylinder 1.

The vehicle height signal A output from the vehicle height sensor 15 when the amount of expansion and contraction of the cylinder 1 increases due to oil supply to the cylinder 1
Level gradually increases. Then, when the level of the vehicle height signal A falls within the reference vehicle height range B (time t ₂ ), the step signal generation circuit 21 detects this and the absolute value is 0 and the value is 0.
Of the first and second low-pass filters 16,
Output to 17. Accordingly, the first and second low-pass filters 16 and 17 generate the long time constant vehicle height pseudo signal h _l and the short time constant vehicle height pseudo signal h _S and output these to the supply / discharge instruction circuit 19.

In this case, the long time constant vehicle height pseudo signal h _l and the short time constant vehicle height pseudo signal h _S will eventually saturate to a value of 0, but the time required for the saturation is longer in the latter case than in the former. It is short. In addition, the short time constant vehicle height pseudo signal h _S
, By greater than the rate of increase of the constant vehicle height pseudo signal h _l when the increase rate is long, compared the level of the constant vehicle height pseudo signal h _l when long time to reach the predetermined value Short.

When the level of the short time constant vehicle height pseudo signal h _S reaches the refueling stop threshold value J (time t ₃ ) (determined to be YES in step S11), the refueling stop instruction signal F is sent to the supply / discharge mechanism. 14, the motor 4 is turned off, the electromagnetic switching type relief valve 13 is opened (on), and the supply / discharge oil valve 7 is opened (on).
As a result, oil is discharged from the cylinder 1.

The processing for draining and stopping the oil discharge is performed in accordance with the steps S13 to S16 in correspondence with the processing for refueling and stopping the oil supply.

As described above, in this vehicle height adjusting device,
The step signal C generated based on the vehicle height signal A is processed by the first and second low-pass filters 16 and 17 in accordance with the respective time constants. Since the oil discharge is stopped, the oil supply / discharge control need not be performed according to the sampling number of the detection signal. For this reason, in this vehicle height adjustment device, the erroneous determination that occurs with the setting of the sampling cycle, which the conventional vehicle height adjustment device has,
There is no problem such as oil supply / discharge chattering or hunting.

Next, a vehicle height adjusting device according to a second embodiment of the present invention will be described with reference to FIGS. Note that the same parts as those of the above-described vehicle height adjustment device of the first embodiment are denoted by the same reference numerals,
The description is omitted. Steps S1 to S5 of the processing contents of the controller 30 of the vehicle height adjusting device are the same as those of FIG. 2 and their description is omitted.

The controller 30 includes an integrating circuit 31, small and large gain circuits 32 and 33, and a saturation processing circuit instead of the first and second low-pass filters 16 and 17 of the vehicle height adjusting device of the first embodiment. 34 and is provided. In the second embodiment, the supply / discharge instruction circuit 19 includes a small gain integration step instead of the long time constant vehicle height pseudo signal h _l and the short time constant vehicle height pseudo signal h _S used in the first embodiment. it is different from that using the signals m _l and large gain integration step signal m _S.

The integration circuit 31 integrates the step signal C from the step signal generation circuit 21. Small and large gain circuits
32 and 33 have small and large gain values less than 1, respectively.
Amplification processing to generate a small gain integral vehicle height signal m _l and large gain integrated vehicle height signal m _S to the signal from the integrator circuit 31. When the level of the signal reaches the predetermined level (+100, -100 in the present embodiment), the saturation processing circuit 34 maintains the level until the next supply / discharge processing and outputs it.

The supply and discharge instruction circuit 19, supplied to and discharged from the supply and discharge mechanism 14 in accordance with the small gain level of the integrated vehicle height signal m _l compared to preset supply and discharge threshold comparison result from the saturation processing circuit 34 supply and discharge instruction signal is output, and the saturation processing large gain integrated vehicle height signal m _S level preset supply and discharge stop threshold as compared to supply and discharge mechanism in accordance with the comparison result from the circuit 34 to perform the 14 And outputs a supply / discharge stop instruction signal for stopping supply / discharge.

Here, a controller comprising the integration circuit 31, small and large gain circuits 32 and 33, a saturation processing circuit 34, a memory 18, a supply / discharge instruction circuit 19, and a step signal generation circuit 21. 30 will be described with reference to FIGS. 2 and 6.

First, initialization is performed by turning on a power switch (not shown) (step S1), and it is determined whether or not a control cycle has elapsed (step S2). If the determination is NO, the determination in step S2 is performed again.

In step S3, a step signal C is inputted from the step signal generating circuit 21, and in a succeeding step S4, a vehicle height determination subroutine is executed. Based on the result of the determination, oil supply / discharge processing is performed in step S5, and vehicle height adjustment is performed.

The vehicle height determination subroutine will be described with reference to FIG. Step S17, respectively in S18 small gain integrated vehicle height signal m _l, it generates a large gain integral vehicle height signal m _S. Subsequent to step S18, it is determined whether the value of the small gain integrated vehicle height signal _ml is smaller than 0 (step S19). If the result is YES, the process proceeds to step S20 (refueling determination step) and if NO, Goes to step S24 (oil drainage determination step).

In step S20, the small gain integrated vehicle height signal m
_It is determined whether or not the level of _l is smaller than the refueling threshold value I. If the determination is YES, a refueling instruction signal D is output to the refueling mechanism 14 to refuel the cylinder 1 (step S21).
After this process, the process returns to the main routine to perform the process.

[0048] If it is determined NO in step S20, the large gain level of the integrated vehicle height signal m _S it is determined whether larger refueling stop threshold J (step S22), and the oil supply stop instruction signal F and determines that YES Output, thereby stopping the refueling of the cylinder 1 (step S23).
After 3, return to the main routine.

If NO is determined in the step S22, the process returns to the main routine. As described above, the refueling of the cylinder 1 and its suspension are performed by the processing of steps S20 to S23.

The following steps S24 to S2
7 performs the drainage of the cylinder 1 and the control of stopping the oil supply in contrast to the processing of the above-described steps S20 to S23 which is the control of the supply of the oil to the cylinder 1 and the control of stopping the oil supply.

In step S24, the small gain integrated vehicle height signal m
_It is determined whether or not the level of _l is greater than the oil discharge threshold value K. If the determination is YES, an oil discharge instruction signal E is output to the supply / discharge mechanism 14 to perform oil discharge from the cylinder 1 (step S25).
After this process, the process returns to the main routine to perform the process.

[0052] If it is determined NO in step S24, the level of the large gain integrated vehicle height signal m _S is determined whether the oil discharge stop threshold smaller than L (step S26), YES if it is determined that the oil discharge stop instruction signal G is output, thereby stopping the draining of oil from the cylinder 1 (step S27).
After that, the process returns to the main routine.

If NO is determined in the step S27, the process returns to the main routine. As described above, by the processing of steps S24 to S27, the drainage of oil from the cylinder 1 and its suspension are performed.

The operation of the vehicle height adjusting device configured as described above will be described with reference to FIGS. The height of the vehicle decreases due to a person getting on the vehicle body or carrying luggage, and the level of the vehicle height signal A falls below the reference vehicle height range B (time t ₀ ).
And a step signal generating circuit 21 outputs a step signal C having a value of -100, and an integrating circuit 31 performs an integrating process on this signal to generate a signal exhibiting a linear function reduction characteristic,
The small and large gain circuits 32 and 33 provide a small gain integrated vehicle height signal m _l ,
It generates a large gain integral vehicle height signal m _S (step S17,
Step S18) This is output to the supply / discharge instruction circuit 19 via the saturation processing circuit.

[0055] In this case, the small gain integrated vehicle height signal m _l, large gain integrated vehicle height signal m _S is, if the level reaches -100, will be maintained by the saturation processing circuit 34 to that level. The small gain integrated vehicle height signal m _l, by the reduction ratio is smaller than the reduction ratio of the large gain integrated vehicle height signal m _S, a large gain integration time until the level reaches a predetermined value many such in comparison with the vehicle height signal m _S.

The level of small gain integrated vehicle height signal _ml reaches refueling threshold value I (time t ₁ ) (YES in step S20)
), The refueling instruction signal D is output to the refueling / discharging mechanism 14 (step S21), the motor 4 is turned on, the electromagnetic switching relief valve 13 is closed (off), and the refueling and draining valve 7 is opened. Valve (on)
Thus, oil is supplied to the cylinder 1.

The vehicle height signal A output from the vehicle height sensor 15 when the amount of expansion and contraction of the cylinder 1 is increased by refueling the cylinder 1
Level gradually increases. Then, when the level of the vehicle height signal A falls within the reference vehicle height range B (time t ₂ ), the step signal generating circuit 21 outputs the step signal C having an absolute value of 100 and a value of 0 via the integrating circuit 31. Output. This makes it small,
Large gain circuits 32 and 33 small gain integrated vehicle height signal m _l in the sheet discharge instruction circuit 19, the large gain integrated vehicle height signal m _S is outputted.

[0058] In this case, the small gain integrated vehicle height signal m _l, large gain integrated vehicle height signal m _S is, if the level reaches -100, will be maintained by the saturation processing circuit 34 to that level. Further, the large gain integrated vehicle height signal m _S, by the increasing rate is greater than the increase in the proportion of the low gain integral vehicle height signal m _l, time small gain integration until the level reaches a predetermined value It is short compared to the vehicle height signal m _l.

[0059] Then, the level of the large gain integrated vehicle height signal m _S reaches a refueling stop threshold J (time t ₃₎ and (YES and determines in step S22), and supply and discharge mechanism fueling stop instruction signal F 14 And the motor 4 is turned off, the electromagnetic switching type relief valve 13 is opened (on), and the supply / discharge oil valve 7 is opened (on).
As a result, oil is discharged from the cylinder 1.

The processing for draining and stopping the oil discharge is performed in accordance with steps S24 to S27 corresponding to the processing for refueling and stopping the oil supply.

As described above, in this vehicle height adjusting device,
Integrating circuit for step signal C generated based on vehicle height signal A
The processing is performed in 31 and the small and large gain circuits 32 and 33, and the supply and discharge of oil and the supply and discharge of oil are stopped based on the signal obtained by this processing. Therefore, the output of the supply / discharge instruction signal is suppressed due to the change in the road surface condition and the vibration caused by the movement of the vehicle body (roll, dive, squat), and excessive supply / discharge is caused when the supply / discharge is stopped. Is suppressed, and problems such as erroneous determination, fluid supply / discharge chattering, and hunting do not occur.

It is to be noted that the supply / discharge control of the oil liquid is performed by setting the sampling cycle of the vehicle height signal to be long, and the suspension control for the supply / discharge of the oil liquid is performed by setting the sampling cycle of the vehicle height signal to be short. You may comprise.

In the above embodiment, the case where the fluid is an oil liquid has been described as an example. However, the present invention is not limited to this, and may be, for example, a gas.

[0064]

According to the first aspect of the present invention, since the vehicle height adjusting device is configured as described above, the step signal generated based on the vehicle height signal is respectively filtered by the first and second low-pass filters. Processing is performed in accordance with the time constant, and the supply and discharge of the fluid and the suspension thereof are performed based on the signal obtained by this processing. Therefore, the supply of fluid is caused by changes in road surface conditions and vibrations caused by body movements (roll, dive, squat). The output of the discharge support signal is suppressed, and the occurrence of excessive supply and discharge when the supply and discharge is stopped is suppressed, and problems such as erroneous determination, fluid supply and discharge chattering and hunting are not caused. .

The second aspect of the present invention is a vehicle height adjusting device configured as described above. Therefore, a step signal generated based on a vehicle height signal is processed by an integrating circuit and a small and large gain circuit. Since the supply and discharge of the fluid and the suspension thereof are performed based on the signal obtained by this processing, it is possible to suppress the output of the supply and discharge support signal due to the change in the road surface condition and the vibration caused by the movement of the vehicle body (roll, dive, squat). In addition, when supply / discharge is stopped, excessive supply / discharge is suppressed, and problems such as erroneous determination, fluid supply / discharge chattering, and hunting do not occur.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a vehicle height adjusting device according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine in control contents of a controller of the vehicle height adjustment device.

FIG. 3 is a flowchart showing a vehicle height determination subroutine in control contents of a controller of the vehicle height adjustment device.

FIG. 4 is a time chart showing an operation example of the vehicle height adjustment device.

FIG. 5 is a view schematically showing a vehicle height adjusting device according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a vehicle height determination subroutine in control contents of a controller of the vehicle height adjustment device.

FIG. 7 is a time chart showing an operation example of the vehicle height adjusting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder 3 Pump 4 Electric motor 7 Supply / drain oil valve 13 Solenoid switching relief valve 14 Supply / discharge mechanism 15 Vehicle height sensor 16 First low-pass filter 17 Second low-pass filter 19 Supply / discharge instruction circuit 20 Controller 21 Step signal generation circuit A vehicle height signal B standard vehicle height range C step signal D fueling command signal E oil discharge instruction signal F fueling stop instruction signal G scavenge stop instruction signal h _l length time constant vehicle height pseudo signal h _S short time constant vehicle height pseudo signal I Oil supply threshold J Oil discharge threshold K Oil supply stop threshold L Oil discharge stop threshold

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-60-209312 (JP, A) JP-A-60-203513 (JP, A) JP-A-2-127113 (JP, A) JP-A-60-203 191803 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60G 17/015

Claims (2)

(57) [Claims] 1. A cylinder interposed between a vehicle body and each wheel side, which expands and contracts by supplying and discharging fluid, a supply and discharge mechanism for supplying and discharging fluid to and from the cylinder, and detects an amount of expansion and contraction of the cylinder. Expansion and contraction amount detection means for outputting an expansion / contraction signal, and comparing the level of the expansion / contraction signal with a preset reference expansion / contraction range, and when the level of the expansion / contraction signal is in an area exceeding the reference expansion / contraction range, If it is in an area smaller than the range, it is positive, negative,
A step signal generating circuit for outputting a step signal of 0;
A first and a second, each having a long and short time constant and outputting a long time constant vehicle height pseudo signal and a short time constant vehicle height pseudo signal by performing signal processing on the step signal according to the time constant. 2 and compares the level of the long time constant vehicle height pseudo signal with a preset supply / discharge threshold value, and outputs a supply / discharge instruction signal for causing the supply / discharge mechanism to supply / discharge to / from the cylinder according to the comparison result. And compares the level of the short time constant vehicle height pseudo signal with a preset supply / discharge stop threshold value and outputs a supply / discharge stop instruction signal for stopping supply / discharge to the cylinder to the supply / discharge mechanism according to the comparison result. A vehicle height adjusting device provided with a supply / discharge instruction circuit. 2. A cylinder interposed between a vehicle body and each wheel side, which expands and contracts by supplying and discharging fluid, a supply and discharge mechanism which supplies and discharges fluid to and from the cylinder, and detects an amount of expansion and contraction of the cylinder. Expansion and contraction amount detecting means for outputting an expansion / contraction signal, and comparing the level of the expansion / contraction signal with a preset reference expansion / contraction range. If it is in an area smaller than the range, it is positive, negative,
A step signal generating circuit for outputting a step signal of 0;
An integration circuit for integrating the step signal; a small gain integration step signal and a large gain integration step signal having amplification values of less than 1 and small and large gain values, respectively, and amplifying the signal from the integration circuit; And a saturation processing circuit that outputs when the level of the signal from the small and large gain circuit reaches a predetermined level and maintains the level until the next supply / discharge processing, Comparing the level of the small gain integration step signal from the saturation processing circuit with a preset supply / discharge threshold value to output a supply / discharge instruction signal for causing the supply / discharge mechanism to supply / discharge to / from the cylinder; The level of the large gain integration step signal from the CPU is compared with a preset supply / discharge stop threshold, and a supply / discharge stop instruction signal for stopping the supply / discharge to the cylinder to the supply / discharge mechanism is output. Vehicle height adjusting device, characterized in that provided between 示回 path.