JPS60203511A - Level control device for automobile - Google Patents

Abstract

PURPOSE:To make level control moderate, by throttling a throttle device installed in a passage of a level contol fluid and thereby constituting it so as to limit a flow rate to some extent at a time when a fact that a car is in a weight variable state is detected. CONSTITUTION:A door open signal out of a door open detector 29 is inputted into a throttle device 9, while such a possibility that there are loading and unloading of loads as well as boarding and alighting of people is inputted too. With this constitution, a solenoid 14a is energized with a continuous rating current from a control unit 15 whereby an on-off select valve 14 is selected to a closing position, and pressure oil is throttled at a throttle valve 13, decreasing pressure oil flow to be supplied or discharge to or from a strut 6. Therefore, the lifting speed of a piston rod 18 of the strut 6 slows down, thus level control becomes moderate. With this constitution, moderate level control comes to fruition nad, what is more, safety and driving comfortableness are well improvable.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vehicle height adjustment device for an automobile.

(Prior art) Since the car body is elastically supported by the axle via a suspension system, the car body rises and falls according to the weight of the car, and the front part of the car sinks when braking suddenly or descending from the platform, and the rear part of the car collapses when climbing up. sinks. On the other hand, if the vehicle body is not raised when driving on rough roads, the vehicle body will be damaged, and if the vehicle body is not lowered when driving at high speeds, running stability will be lacking and aerodynamic characteristics will be disadvantageous.

To solve this problem, conventional vehicle height adjustment devices have been equipped with a vehicle height sensor between the vehicle body and the axle, and feedbank controlled the amount of expansion and contraction of the fluid pressure cylinder of the suspension system so that the detected vehicle height falls within the target vehicle height setting range. have been put into practical use in various ways.

For example, the vehicle height adjustment device described in JP-A No. 57-118906↓ includes an air cylinder of a suspension system, an air supply device that supplies air to the air cylinder, a vehicle height sensor installed in the suspension system, and a vehicle height adjustment device. Equipped with a high-level control device, it compares the vehicle height detected at each point in time by the vehicle height sensor with the time-series smoothed value of the detected vehicle height, determines the road condition based on the vibration state of the former relative to the latter, and adjusts the target vehicle height accordingly. is automatically set, the detected vehicle height is compared with the target vehicle height, and feedback vehicle height adjustment is performed in the direction in which the former matches the latter.

However, according to the above-mentioned vehicle height adjustment device, when loading and unloading cargo into a car, as soon as the vehicle height changes due to a change in the weight of the car, the vehicle height adjustment device automatically operates and adjusts the vehicle height. The vehicle height will be adjusted so that it returns to the same predetermined height as before.

For example, when loading luggage several times, the vehicle body lowers as the luggage is loaded, then immediately rises rapidly as the vehicle height is adjusted. This not only causes extreme discomfort for those loading and unloading cargo, but also poses a problem in that the work is not safe because the amount of change in vehicle height is large, especially when loading heavy objects.

In addition, not only when loading and unloading cargo, but also when people get on and off, especially when multiple people get on and off, the vertical fluctuations are large.
It is accompanied by some discomfort.

(Purpose of the Invention) The present invention has been made in view of the above-mentioned problems, and is a system that allows gradual adjustment of the vehicle height when the weight of the vehicle changes, such as when loading and unloading luggage or when people get on and off the vehicle. The purpose is to provide a vehicle height adjustment device for automobiles.

(Structure of the Invention) The vehicle height adjustment device for an automobile according to the present invention is provided with an adjustment means for adjusting the vehicle height using pressurized fluid stored in a cylinder chamber between the vehicle body and the axle.

Connecting the vehicle chamber and the control means through a fluid passage, and automatically controlling the vehicle height to a predetermined height by supplying pressurized fluid to or discharging pressurized fluid from the adjustment means using the control means;
A detection means for detecting a state in which the weight of the automobile may change is provided, and a restricting means receives a detection signal from the detection means to limit the flow rate of the pressurized fluid flowing through the fluid passage when the weight of the automobile is in a state in which the weight may change. This allows the vehicle height to be adjusted gradually.

(Effects of the Invention) Since the present invention is configured as described above, the detection means detects a state in which the weight of the automobile may change, that is, a state in which cargo may be loaded or unloaded or a person may get on or off the vehicle, and the detection signal may be detected by the detection means. Based on this, the flow rate of the pressurized fluid flowing through the fluid passage is restricted by the throttle means, so that the vehicle height adjustment is performed gradually and gently when restoring and correcting changes in vehicle height due to weight fluctuations.

Therefore, when loading or unloading cargo or getting on and off the vehicle, the violent vertical movement of the vehicle body due to vehicle height adjustment is greatly reduced, eliminating the discomfort of passengers and improving the safety of loading and unloading cargo. do.

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

As shown in Fig. 1, this vehicle height adjustment device for a vehicle has a control unit 3 that receives detection signals from a vehicle height sensor 1 and a vehicle speed sensor 2, determines the road surface condition, and adjusts the vehicle height according to the road surface condition and vehicle speed. The vehicle height is automatically adjusted by calculating a target vehicle height and operating the oil passage switching valve 4 to supply and discharge pressure oil to the strut cylinders 6 of each wheel 5 so as to achieve the target vehicle height. When there is a possibility that cargo is being loaded or unloaded from the vehicle or people are getting on or off the vehicle, the flow of pressure oil flowing through the oil passage 7 is throttled to slow down the vehicle height adjustment speed.

That is, the vehicle height adjustment device includes a vehicle height sensor 1 corresponding to each wheel 5, a vehicle speed sensor 2, a control unit 3, a hydraulic pressure supply device 8, an oil passage switching valve 4, an oil passage 7, , a throttle device 9 interposed in each of the front wheel oil passage 7a and the rear wheel oil passage 7b.
, the door opening detection device 29 , the axle 10 of each wheel 5 and the vehicle body 1
Strut 6 attached between 1 and accumulator 1
It consists of 2.

The vehicle height sensor 1 is composed of, for example, a rotary potentiometer, and is interposed between the vehicle body 11 near each wheel 5 and the link arm of the suspension system, and is adapted to the vertical movement of the link arm corresponding to the elevation of the vehicle body 11. The resistance value increases or decreases accordingly, and the vehicle height is detected from the fluctuation of this resistance value, and the detection signal is output to the control unit 3, but various other vehicle height sensors may be used. Good too.

The vehicle speed sensor 2 detects the rotation of the drive main shaft using existing rotation detecting means (for example, one consisting of a rotating disk with a slit, a light source, and a phototransistor, or one consisting of a rotating disk and a pickup sensor, etc.). The signal is output to the control unit 3.

The control unit 3 includes a data processing section, a road surface condition determination section,
It consists of a target vehicle height calculation section, a vehicle height comparison section, and a switching valve drive section.

The data processing section processes the detection signals from each vehicle height sensor 1 to calculate the actual vehicle height, for example, every 10 m5ec. The vehicle speed is calculated by processing the detection signal from the above, and the deviation of the instantaneous actual vehicle height from the smoothed value, that is, the amplitude of the vertical vibration, is calculated, as the actual vehicle height fluctuates vertically depending on the road surface condition. .

The road surface condition determination section determines the road surface condition based on the vehicle height amplitude obtained from the detection signal of each vehicle height sensor 1.

The target vehicle height calculation section calculates a target vehicle height based on the road surface condition obtained by the road surface condition determination section and the vehicle speed obtained by the data processing section.

In this case, assuming the road surface condition is constant, the relationship between vehicle speed and target vehicle height is set such that the target vehicle height decreases in stages as the vehicle speed increases. This is to improve performance and aerodynamic characteristics.

Further, regarding the relationship between the road surface condition and the target vehicle height, the target vehicle height is set to increase in stages as the road surface condition worsens, and this is to prevent damage to the vehicle due to rough roads.

The vehicle height comparison section calculates a vehicle height average value of the smoothed vehicle height values every 10 seconds, for example, and calculates a deviation of the vehicle height average value from the target vehicle height.

The switching valve drive section receives a vehicle height deviation signal from the vehicle height comparison section, and outputs a drive current to the oil supply solenoid 4a of the oil path switching valve 4 when the average vehicle height value is lower than the allowable range of the target vehicle height. On the contrary, when the vehicle height average value is higher than the allowable range of the target vehicle height, a drive current is output to the oil draining solenoid 4b.

Each part of the control unit 3 may be constructed using an analog circuit, or may be constructed using a digital circuit such as a microcomputer.

The hydraulic pressure supply device 8 is a directional discharge type constant displacement hydraulic pump 8b driven by a motor 8a, the discharge pressure is kept constant by a relief valve 8c, and the oil passage switching valve 4 is a 4-point/3-position switching valve. In the illustrated position, the pressure oil from the hydraulic pump 8b is relieved, and the front wheel oil passage 7a and the rear wheel oil passage 7b are cut off, and when the oil supply solenoid 4a is energized and switched to the oil supply position, the pressure is reduced. Oil is supplied to the inner oil passages 7a and 7b, and when the supply and discharge solenoid 4b is energized and switched to the oil drain position, pressure oil from the inner oil passages 7a and 7b is discharged to the oil tank 8d. There is.

The throttle device 9 mentioned above is installed in the front wheel oil passage 7a and the rear wheel oil passage 7b, respectively, and the throttle valve 13 is connected to the oil v
It consists of a flow rate control valve and a flow rate adjustment control unit 15, each of which is connected in parallel with an oil passage connected to a two-bottom, two-position on/off switching valve I4, and connected in series to each oil passage 7a and 7b. , the on/off switching valve 14 of this flow rate control valve is controlled by the control unit 1.
This control unit 15 is a solenoid valve that can be switched open and closed with a switch 5, and this control unit 15 is operated when the signal output from the open door detection device 29 is "L".
(predetermined low level signal), the on-off switching valve 14 is held in the open position without energizing the solenoid 14a, and in contrast to the above, the signal output from the door opening detection device 29 is "H".
” (predetermined high level signal), solenoid 14a
The on-off switching valve 14 is switched to the closed position by energizing the on-off switching valve 14.

When the on-off switching valve 14 is in the open position, the oil passage 7a
- The flow of pressure oil in 7b is not throttled and most of it flows smoothly from the on-off switching valve 14, but when the on-off switching valve 14 is switched to the closed position, the flow of pressure oil is throttled by the throttle valve 13 and the The flow rate is reduced to about 1/2 to 1/3.

The open door detection device 29 is constructed by connecting a plurality of limit switches 30 to the input terminal of an OR gate 31, each of which detects the open state of each side door, back door, and trunk lid of the automobile. The output terminal is connected to a control unit 15 of the diaphragm device 9.

When at least one of the doors, trunk lid, etc. is opened and there is a possibility that a person may get on or off the vehicle to load or unload cargo, at least one limit switch 30 is ON, and the output of the OR gate 31 becomes rHJ. The solenoid 14a is energized via the control unit 15, and the on-off switching valve 14 is switched to the closed position.

In addition, when all doors and trunk lids are closed, all limit switches 3o are OFF and the above O
The output of the R gate 31 becomes rLJ, and the solenoid 14a
is not excited, and the on-off switching valve 14 is held in the open position.

The strut 6 is a hydraulic cylinder interposed between the housing 16 and the vehicle body 11 at the connection between the axle 1o and the wheel 5, and functions as a suspension strut and shock absorber as well as a vehicle height adjustment means. It is something.

As shown in FIGS. 2 and 3, the lower end of the cylinder body 17 of the strut 6 is fixed to the housing 16 via a sleeve-shaped coupling member 19, and a piston rod 18 projects upward from the cylinder body 17. The upper end portion of is connected to the vehicle body 11 via a mount washer 20 and an annular cushioning rubber 21.

A piston valve 2 is provided at the lower end of the piston rod 18.
2 is provided, and an oil hole 23 opened at the lower end of the piston rod 18 and provided through the piston rod 18 is connected to the oil passages 7a and 7b at the upper end side of the piston rod 18, and the oil hole 23 of the diaphragm type accumulator 12 connected to the room.

The piston valve 22 is the orifice 2 of the piston 24.
The upper oil is By restricting the oil flow from the chamber 27a to the lower oil chamber 27b, the strut cylinder 6 is buffered to prevent sudden expansion, and the contraction damping valve allows the oil flow to flow from the lower oil chamber 27b to the upper oil chamber 27.
By restricting the oil flow to a, the strut 6 is damped to prevent it from contracting rapidly, thereby functioning as a shock absorber.

The accumulator 12 is for absorbing high frequency pressure pulsations of the pressure oil due to high frequency vibrations propagating from the road surface to the wheels 5.

When pressure oil is supplied to the strut 6 from the oil passages 7a and 7b, the amount of oil in the lower oil chamber 27b and upper oil chamber 27a increases, so the piston rod 18 extends upward and the vehicle height is adjusted higher. On the contrary, when the pressure oil is discharged from the strut 6 through the oil passages 7a and 7b, the amount of oil decreases, so the piston rod 18 contracts downward and the vehicle height is adjusted lower.

Incidentally, reference numeral 28 is a stopper for regulating the maximum vehicle height.

The operation in the above configuration is as follows.

As already explained, the control unit 3 determines the road surface condition using the detection signals from the vehicle height sensor 1 and the vehicle speed sensor 2, and sets a target vehicle height that is adapted to the road surface condition and vehicle speed. and the vehicle height average value are compared.

When the vehicle height average value is lower than the allowable range of the target vehicle height, the oil supply solenoid 4a is energized and the oil passage switching valve 4 is energized.
is switched to the oil supply position, and pressure oil at a predetermined pressure is supplied to the hydraulic pump 8.
Oil is supplied from b to each strut 6 via oil passage 7, and this strut 6 extends to adjust the vehicle height higher.As a result, when the average vehicle height falls within the allowable range of the target vehicle height, oil is supplied to each strut 6. The energization of the solenoid 4a is stopped, and the oil passage switching valve 4 returns to the cutoff position.

Contrary to the above, when the average vehicle height is higher than the allowable range of the target vehicle height, the oil draining solenoid 4b is energized, the oil passage switching valve 4 is switched to the oil draining position, and the pressure oil is transferred from each strut 6 to the oil draining position. is discharged through the oil path 7, the strut 6 contracts and the vehicle height is lowered (adjusted), and as a result, when the average vehicle height falls within the allowable range of the target vehicle height, the energization to the oil draining solenoid 4b is stopped. The oil passage switching valve 4 returns to the shutoff position.

On the other hand, the control unit 15 of the diaphragm device 9
When all the doors and trunk lids are closed in response to the detection signal from the door opening detection device 29 and there is no possibility of people getting in or out of the vehicle without loading or unloading the luggage, the rLJ signal is received from the open door detection device 29 and the solenoid 14a is not energized. Since the on-off switching valve 14 is held in the open position, the flow rate control valve does not restrict the flow rate of pressure oil, and the flow rate of pressure oil supplied to and discharged from the strut is large, and the vertical speed of the piston rod 18 of the strut 6 is controlled. Since the speed becomes faster, vehicle height adjustment can be performed quickly.

Furthermore, when at least one door or trunk lid is opened and there is a possibility that a person may get on or off the vehicle while loading or unloading luggage, the control unit 15 energizes the solenoid 14a upon receiving an "H" signal from the door opening detection device 29. As a result, the on/off switching valve 14 is switched to the closed position, so that the pressure oil is transferred to the throttle valve 1.
3, the flow rate control valve is in a state where the flow rate of the pressure oil is throttled to about 1/2 to 1/3,
The flow rate of the pressurized oil supplied to and discharged from the strut 6 is significantly reduced, and the vertical speed of the piston rod 18 of the strut 6 is slowed down, so that the vehicle height adjustment is performed gradually and slowly.

As described above, when at least one of the doors or trunk lid is opened and there is a possibility that passengers may get on or off the vehicle to load or unload cargo, the oil passages 7a and 7b are constricted and the vehicle height is gradually adjusted. There is no deterioration in passenger comfort, and loading and unloading operations are safe.

Moreover, the throttle device 9 has a simple structure and can be added to the existing vehicle height adjustment device.
This can be realized by simply adding the door open detection device 29.

Note that the above embodiment may be partially modified as follows.

First modification: The oil passage switching valves 4 are provided independently for the front wheels and for the rear wheels, and are configured to adjust the vehicle height of the front wheels and the rear wheels independently.

The flow rate control valve of the second modification 2-throttle device 9 is a control unit) 1
It consists of an electrically controlled variable throttle valve.

Third variation: The driver judges the road surface condition,
The system is configured to select the road surface condition step by step using a manual select switch and output it to the control unit 3, calculate a target vehicle height from the road surface condition and vehicle speed, and compare the target vehicle height with the vehicle height average value. to feedback control the vehicle height.

Fourth modification: An air supply device is provided in place of the hydraulic pressure supply device 8, and the struts 6 are driven by air.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall configuration diagram, FIG. 2 is a longitudinal sectional front view of a strut, and FIG. 3 is an enlarged view of the section (■) in FIG. 2. 1. Vehicle height sensor, 2. Vehicle speed sensor, 3. Control unit, 4. Oil passage switching valve, 6. Strut.
7. Oil path, 8. Hydraulic pressure supply device, 9. Throttle device, 1o. Axle, 11. Vehicle body, 13. Throttle valve.
14... Open/close switching valve, 15... Control unit for flow rate adjustment, 27a... Upper oil chamber, 27b... Lower oil chamber,
29...Open door detection device, 3o...Limit switch,
31...OR gate. Patent applicant: Toyo Kogyo Co., Ltd. Figure 2

Claims (1)

[Claims] an adjusting means attached between the vehicle body and the axle, which adjusts the vehicle height with pressurized fluid stored in the cylinder chamber thereof; and a fluid passageway connected to the cylinder chamber of the adjusting means; A control means that is connected to the adjustment means through the fluid passage and automatically controls the vehicle to a predetermined vehicle height by supplying pressurized fluid to or discharging the pressurized fluid from the adjustment means, and a control means that changes the weight of the automobile. and a throttle means for restricting the flow rate of the pressurized fluid flowing through the fluid passage when the weight of the automobile is in a state where the weight of the automobile may change in response to a detection signal from the detection means. An automobile vehicle height adjustment device characterized by