JPH0569004B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to a vehicle height adjustment device for an automobile, which adjusts the vehicle height using supply and discharge of a working fluid such as compressed air. (Prior Art) Some vehicle height adjustment devices for automobiles are designed to adjust the vehicle height according to the supply and discharge of working fluid. That is, as shown in Japanese Utility Model Application Publication No. 58-139306, when increasing the vehicle height by disposing, for example, a pneumatic spring device as a vehicle height adjustment body between the wheels and the vehicle body, the air pressure from the compressed air source is When compressed air is supplied to each pneumatic spring device of the front and rear wheels, or only to the pneumatic spring device of one side of the front and rear wheels, conversely, when lowering the vehicle height, supply compressed air to each pneumatic spring device of the front and rear wheels. The compressed air is discharged to the atmosphere only from each pneumatic spring device or the pneumatic spring device on either one of the front wheels or the rear wheels. In this type of vehicle height adjustment device, the vehicle height can be adjusted to a "high" level using a manually operated vehicle height switching means.
Alternatively, there are many options that can be selected as desired, such as "low". Therefore, a vehicle height sensor is provided to detect the vehicle height, and the vehicle height detected by the vehicle height sensor, that is, the actual vehicle height, is Feedback control is performed so that the set vehicle height target value is set by the manual switching means. Incidentally, it is undesirable from the viewpoint of ensuring the reliability of the various devices for adjusting the vehicle height and safety, etc., to change the vehicle height unnecessarily while the vehicle is running. The vehicle height can be adjusted using a manual switching means only when the vehicle is stopped. (Problems to be Solved by the Invention) However, it is inconvenient that the vehicle height cannot be adjusted at all by manual operation while the vehicle is running, and does not necessarily meet the needs of the driver. Therefore, it is an object of the present invention to prevent as much as possible unnecessary vehicle height adjustments based on manual operations while driving, while also making it possible to perform the minimum necessary vehicle height adjustment through manual operations while driving. An object of the present invention is to provide a vehicle height adjustment device for an automobile. (Means and operations for solving the problem) In order to achieve the above-mentioned object, as shown in FIG. a vehicle height adjustment body that changes the vehicle height according to the height of the vehicle; a working fluid supply and discharge means that adjusts the supply and discharge of working fluid to the vehicle height adjustment body; a vehicle height detection means that detects the vehicle height of the automobile; a vehicle height control means for controlling the ejection means so that the vehicle height detected by the vehicle height detection means becomes a set vehicle height target value; a vehicle speed detection means for detecting the vehicle speed of the automobile; manual switching means for switching the set vehicle height target value; and receiving an output from the vehicle speed detection means, and when the vehicle speed is equal to or higher than a predetermined set vehicle speed, controlling the vehicle height based on the output from the manual switching means. A control range regulating means that allows vehicle height adjustment by the means only for a predetermined period of time; With this configuration, manual operations while the vehicle is running are performed only within a limited period of time, ie, a predetermined period of time, and frequent and large changes in the vehicle height while the vehicle is running are prohibited. (Example) Examples of the present invention will be described below with reference to the attached drawings. In Fig. 1, 1 is the vehicle body, 2 is the left front wheel, 3 is the right front wheel, 4 is the left rear wheel, and 5 is the right rear wheel. A pneumatic spring device 6, 7, 8 or 9 is provided. The pneumatic spring devices 6 to 9 have the same configuration, and as shown in FIG.
A gas chamber 12 is connected by a diaphragm 11 between
When compressed air is supplied to the gas chamber 12, the gas chamber 12 expands to raise the vehicle height, and conversely, when the compressed air is discharged from the gas chamber 12, the vehicle height is lowered. Reference numeral 21 in FIG. 2 denotes a compressor as a compressed air source driven by a motor 22, and this compressor 21 is connected to the gas chamber 13 of each pneumatic spring device 6 to 9 via a pneumatic passage 23. . This air pressure passage 23 includes a common passage portion 23a extending from the compressed air discharge port of the compressor 21;
It has two dedicated passage parts 23b and 23c branched from this common passage part 23a. One dedicated passage section 23b is connected to the gas chamber 13 in each pneumatic spring device 6, 7 on the front wheels 2, 3 side as a pneumatic passage system for the front wheels, and the other dedicated passage section 23c is connected to the gas chamber 13 in each pneumatic spring device 6, 7 on the front wheels 2, 3 side. As a pneumatic passage system, it is connected to the gas chamber 12 in the pneumatic spring devices 8, 9 on the rear wheels 4, 5 side. A dryer 24 containing a dehumidifying agent such as silica gel is connected to the common passage section 23a, and a common exhaust valve 25 consisting of an electromagnetic shut-off valve is connected on the upstream side of the dryer 24, that is, on the compressor 21 side. . Further, an electromagnetic opening/closing valve 26 is connected to the dedicated passage section 23b for the front wheels, and this opening/closing valve 26
A front wheel exclusive exhaust valve 27 consisting of an electromagnetic opening/closing valve is connected to the downstream side (gas chamber 12 side) of the exhaust valve 27 . Similarly, an electromagnetic opening/closing valve 28 and a rear wheel exclusive exhaust valve 29 formed of an electromagnetic opening/closing valve are connected to the rear wheel exclusive passage section 23c as well.
Further, a compressed air storage tank 30 is connected to the common passage section 23a via a communication passage section 23d, and an electromagnetic on-off valve 31 is connected to the communication passage section 23d. Note that a relief valve 32 is connected to the common passage portion 23a, which opens when the internal pressure exceeds a predetermined pressure in order to prevent overpressure. The compressor 21, motor 22, dryer 24, and common exhaust valve 25 are constructed as a unit body A as shown in FIG. As shown in the figure, it is constructed as a unit body B. Reference numeral 41 in FIG. 2 is a control unit consisting of a microcomputer, and this control unit 41 includes sensors 42, 43, 44 and switches 45, 4.
6, while the control unit 41 receives input from the motor 22 and each valve 25, 26, 2.
7, 28, 29, and 31. Among the sensors 42 to 44, sensor 42 detects the vehicle height at the front of the vehicle, sensor 43 detects the vehicle height at the rear of the vehicle, and sensor 44 detects the vehicle speed. In addition, the switch 45,
Among the switches 46, the switch 45 detects whether the pressure inside the tank 30 is maintained at a predetermined pressure or higher. Further, the switch 46 is provided near the driver's seat, and can be set to "standard vehicle height" by manual operation of the driver's vehicle, for example, by automatic vehicle height adjustment (auto).
(auto mode), as well as manual mode, which selects a command to set the vehicle height to "high" or a command to set the vehicle height to "low", that is, a command to set the target vehicle height value. It is. Next, the operation of the hydraulic circuit as described above will be explained, but first the overall outline will be explained. The compressed air obtained by the compressor 21 passes through the dryer 24 and is dried, and then passes through the on-off valve 31 and is temporarily stored in the tank 3.
When the vehicle height is increased, the gas is basically supplied from this tank 30 to the gas chambers 12 of the front or rear wheels. When the pressure within the tank 30 is not sufficiently increased, the switch 45 detects that the compressor 31 supplies gas directly to each gas chamber 12. Here, the manually operated vehicle height changeover switch 4
6 is "Manual mode" depending on the selection.
In the example, the vehicle height is increased overall (both the front and rear of the vehicle body 1) The vehicle height is decreased overall Vehicle height maintained at the front of the vehicle body and the rear of the vehicle lowered The vehicle height maintained at the front of the vehicle body and the rear of the vehicle increased Front of the vehicle body Down/maintain rear vehicle height Front of vehicle up/maintain rear vehicle height Front of vehicle down/rear of vehicle up Eight modes (commands) are possible: front of vehicle up, rear of vehicle down. . Each valve 25-2 for each aspect mentioned above
The relationship between the operating conditions of 9 and 31 is summarized in the following table.

[Table] Note that when the pressure in the tank 30 is insufficient and there is no need to adjust the vehicle height, only the on-off valve 31 of each valve is opened, and the compressor 21 operates to reduce the pressure in the tank 30. Pressure is increased. Also, when it is necessary to raise the vehicle height when the internal pressure in the tank 30 is insufficient, the compressor 21 is operated to supply compressed air from there to the gas chamber 12 for raising the vehicle height. However, replenishment of compressed air to the tank 30 may be done during this vehicle height adjustment (by opening the on-off valve 31), or may be done after the vehicle height adjustment has been completed (while the vehicle height is being adjusted, the on-off valve 31 may be refilled). (Close valve 31). Next, we will discuss the control unit 4 in relation to the manual switch 46 for vehicle speed and vehicle height commands.
The details of control according to No. 1 will be explained based on the flowchart of FIG. In addition, in this FIG. 3, the predetermined time (T) after operating the switch 46
Until the time elapses, the vehicle height can be adjusted in accordance with the "high" or "low" selected by this switch 46. Also, switch 46
When "Auto" is selected, the vehicle height is automatically adjusted regardless of vehicle speed.
Based on the above, the vehicle speed V is read in step S1, and the current vehicle height H is read in step S2. After this, in step S3,
It is determined whether the switch 46 is currently in the "auto" mode. In the determination in step S3 above, switch 4
6 is a mode other than "auto", that is, when the driver's desired "high" or "low""manualmode" is selected, the process moves to step S4, where the vehicle speed V is set to the set vehicle speed Vo ( For example, 4km/
h) It is determined whether or not it is greater than or equal to the above. When it is determined in step S4 that V≧Vo, it is determined in step S5 whether or not the previous mode of the switch 46 was "auto". In other words, from "auto mode" to "manual mode"
It is determined whether or not this is the initial time of switching. And if the previous time was "auto mode",
Since this is when switching to "manual mode", the timer is set (counting starts) in step S6.
Then, in step S7, it is determined whether or not the count value of this timer has elapsed for a predetermined time To (for example, 100 seconds). In the determination in step S7 above, when it is determined that T≧To is not satisfied, that is, when the predetermined time To has not elapsed since switching to "manual mode", the vehicle height selected in this "manual mode" is set. That is, it is determined in step S8 whether the set vehicle height target value is "high" or "low". When it is "high", the set vehicle height target value Ho is set to a high value corresponding to "high" (step S9), and when it is "low", the set vehicle height target value Ho is set to "low". It is set to a corresponding low value (step S10). After step S9 or S10 above, step
Move to S11 and set the target vehicle height value Ho and step
A comparison is made with the actual vehicle height H at S2, and the vehicle height is adjusted based on this comparison. That is, when the actual vehicle height H is larger than the set vehicle height target value Ho, the vehicle height is lowered in step S12 (step S12), and the actual vehicle height H is set to the set vehicle height target value Ho.
If it is smaller than , the vehicle height is increased (step S13). Then, when the actual vehicle height H is equal to the set vehicle height target value Ho, the vehicle height is maintained as it is. On the other hand, if it is determined that the vehicle is in "auto mode" in step S3, the timer is reset in step S14 (the count value after the timer was set in step S6 is cleared), and then the set vehicle height is reset in step S15. Target value Ho
is set as the "standard" value corresponding to "auto mode". Note that after step S15, the processes from step S11 described above are performed, and the vehicle height is automatically adjusted so that it is always at the "standard" height. In the embodiment, when determining the actual vehicle height, the average value of a plurality of vehicle height values obtained by sampling the outputs from the vehicle height sensors 42 and 43 every predetermined unit time is used as the actual vehicle height ( step
(corresponds to H in S2), the vehicle height sampling period is set to, for example, 3 seconds when the vehicle speed V is 4 km/h or less to speed up the response of vehicle height adjustment as much as possible, while when the vehicle speed is 4 km/h or more, the vehicle height sampling period is set to 3 seconds. This sampling period is set to 8 seconds, for example, so that the responsiveness of vehicle height adjustment becomes slow. In other words, we consider that a vehicle speed of 4 km/h or less is when the vehicle is stopped, and by focusing on the fact that when the vehicle is stopped, the sprung weight tends to change significantly due to passengers getting on and off, loading and unloading luggage, etc., and the vehicle height at this time is determined. In order to speed up the responsiveness of the adjustment, the sampling period of the vehicle height H is shortened as described above. On the other hand, when the vehicle speed is 4 km/h or more, which is considered to be in motion, the vehicle height changes temporarily as the vehicle turns, accelerates, decelerates, etc. In order not to react too sensitively to changes, the sampling period is lengthened as described above to slow down the responsiveness of vehicle height adjustment. Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases. In Fig. 3, the vehicle height can be manually changed as many times as desired during a predetermined time To, but with this predetermined time To as the maximum adjustment time,
After one vehicle height adjustment based on manual switching during this period, the vehicle height adjustment may be prohibited even before the predetermined time To has elapsed. Furthermore, after the first vehicle height adjustment by manual switching is completed, subsequent vehicle height adjustments are prohibited, that is, the time required to complete the vehicle height adjustment by switching is set as a predetermined time. Good too. Oil may be used as the working fluid. In this case, the vehicle height adjusting body is a telescopic cylinder unit installed between the wheels and the vehicle body, and the oil is applied to the fluid chamber in the cylinder unit. The height of the vehicle may be changed according to the supply and discharge of the fuel. When the control unit 41 is composed of a microcomputer, it may be of either a digital type or an analog type. Even in the case of the "auto mode", when the vehicle speed exceeds a predetermined value, the automatic adjustment may be prohibited, that is, the processing after step S11 may not be performed. (Effects of the Invention) As is clear from the above, the present invention has the following advantages:
When the vehicle speed exceeds a predetermined value, the vehicle height adjustment by manual switching, which would result in a large change in vehicle height, is only allowed to the minimum necessary level, so the driver can easily adjust the vehicle height. This is preferable from the viewpoint of ensuring reliability and safety by prohibiting unnecessary changes in vehicle height while satisfying the requirements and reducing the frequency of use of equipment for adjusting vehicle height.

[Brief explanation of the drawing]

FIG. 1 is a diagonal diagram showing an embodiment of the present invention. Second
The figure is a circuit diagram of the embodiment shown in FIG. 1. FIG. 3 is a flowchart showing a control example of the present invention. FIG. 4 is an overall configuration diagram of the present invention. 1: Vehicle body, 2-5: Wheels, 6-9: Pneumatic spring device (vehicle height adjustment body), 11: Diaphragm, 1
2: Gas chamber, 21: Compressor (compressed air source),
23a: Pneumatic passage, 23b: Dedicated passage part (pneumatic passage system for front wheels), 23c: Dedicated passage part (pneumatic passage system for rear wheels), 25, 27, 29: Valve (working fluid supply and discharge means), 26, 28 , 41: control unit, 42, 43: vehicle height sensor, 44: vehicle speed sensor, 46: vehicle height switching switch (manual switching means).

Claims (1)

[Scope of Claims] 1. A vehicle height adjusting body disposed between a wheel and a vehicle body and changing the vehicle height according to the supply and discharge of working fluid; and a working fluid that adjusts the supply and discharge of working fluid to the vehicle height adjusting body. a supply/discharge means; a vehicle height detection means for detecting a vehicle height of the automobile; and the working fluid supply/discharge means are controlled so that the vehicle height detected by the vehicle height detection means becomes a set vehicle height target value. vehicle height control means for detecting the vehicle speed; vehicle speed detection means for detecting the vehicle speed of the automobile; manual switching means for switching the set vehicle height target value by manual operation; and control range regulating means that allows vehicle height adjustment by the vehicle height control means based on the output from the manual switching means only for a predetermined time when the vehicle speed is higher than a set vehicle speed. Vehicle height adjustment device.