JP2005239077A - Air spring control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air spring control device capable of continuing automobile high maintaining control even when an air leak detection control device becomes in a failure mode. <P>SOLUTION: The air spring control device has four-system air springs 13, 14 installed between both ends of rear two shafts and a load-carrying platform D of the vehicle; air feed/discharge system connection parts a1-a4, b for connecting a group of air springs with an air tank 17; an air feed/discharge means 20 for feeding or discharging compression air of the air tank to the group of air springs; a control means 19 for controlling feeding/discharging of the compression air to the group of air springs such that vehicle height is coincident with a target value Ho; and an air leak detection means A2 for detecting leakage of air. The air leak detection means A2 has a specifying means A2a for specifying the air spring in which the leak of air is generated based on operation information sp1-sp4 and an air feed stopping means A3 stops feeding of the compression air only to the specified air spring system. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air spring control device that can perform vehicle height maintenance control by operating air supply and discharge to and from an air spring, and more particularly, to an air spring control device that can perform air leak detection processing of an air spring system.

  As shown in FIG. 7, the electronically controlled air suspension device supplies and exhausts high-pressure air from the air supply source side to each of the air springs 110 a to 110 d via a magnet valve (M / V) 120. Maintenance control is performed. The air suspension ECU 130, which is an electronic control unit that controls the magnet valve (M / V) 120, detects the vehicle height on the left and right sides of the vehicle body with the height sensors 140 and 150 in the vehicle height maintenance control, and the corresponding magnet valve (M / V ) By driving 120, air is supplied to and exhausted from the air springs 110a to 110d, and the target vehicle height is maintained. In this vehicle height maintenance control, the electromagnetic valve 120 is switched and driven by inputting a target vehicle height signal to the air suspension ECU 130, which is an electronic control device, and the vehicle height is adjusted to an arbitrary height. It is also possible to automatically facilitate loading and unloading of luggage by eliminating the difference in level with the cargo bed.

  By the way, such an air suspension ECU performs an air leak detection control of an air spring system together with a vehicle height maintenance control. In this air leak detection control device, the vehicle height is detected by the height sensors 140 and 150, and the air springs 110a to 110a are continuously operated for a predetermined time or more when traveling at a predetermined vehicle speed or more excluding when the vehicle is loaded and unloaded. If the target vehicle height cannot be obtained even when air is supplied into 110d, it is determined that there is an airline failure (air leakage) or some abnormality. When air line failure is detected in this way, the air suspension ECU 130 fixes the magnet valve (M / V) on the closed side to stop the vehicle height maintenance control, turns on the error display (error mode), and continues the high pressure Prevents further release of air.

  In this way, the air spring system air leak detection used for automobile high maintenance control prevents excessive consumption of high-pressure air on the air supply source side, and the durability decreases due to continuous operation of the compressor and air dryer. This prevents the supply of high-pressure air to the brake system using the same air source from stagnation.

  An air spring control device that performs air leak detection control of an air spring system together with such vehicle height maintenance control is disclosed in, for example, Japanese Patent Application Laid-Open No. 10-166831 (Patent Document 1).

JP-A-10-166831

Incidentally, as disclosed in Patent Document 1 and the like, in an air spring control device that performs air leak detection control of an air spring system together with automobile height maintenance control, one of a plurality of air spring systems has failed during air leak detection. Even so, the supply / exhaust of other airline systems that have not failed is also stopped.
For this reason, once the air leakage is detected, the vehicle height maintenance control becomes impossible. In particular, when the error mode is entered with the bottom of the air spring exhausted, the road surface reaction force buffering function is greatly reduced, and this road surface reaction force is directly applied to the cargo being transported. On the other hand, there is a risk of adverse effects, and improvements are desired.

  The present invention has been made on the basis of the above-described problems. The object of the present invention is to meet the degree of error mode even when the air leak detection control device employed in the air spring control device is in error mode. It is therefore an object of the present invention to provide an air spring control device that can continue the vehicle height maintenance control and suppress adverse effects on the load during the error mode operation.

  According to a first aspect of the present invention, there is provided an air spring control device provided in a rear two-axle vehicle for carrying goods, wherein four systems of air mounted between both ends of the rear two axles and the loading platform of the vehicle. An air spring group comprising springs, an air tank for storing compressed air, a supply / exhaust system connecting part for connecting the air tank and the air spring group, and a compression stored in the air tank provided at the supply / exhaust system connecting part Supply / exhaust means for supplying / exhausting air to / from the air spring group, vehicle height detecting means for detecting the vehicle height of the vehicle, and control of supply / exhaust of compressed air to / from the air spring group via the supply / exhaust means Control means for controlling the vehicle height so as to match the target value, and an air supply stop for stopping the supply of compressed air to any of the four air springs in preference to the control means. And an air leak detecting means for detecting an air leak of the air spring group, wherein the air leak detecting means includes operation information of each air spring system for each of the four air springs. Based on the air spring system in which the air leakage occurs and the air supply system in which the air leakage has occurred. When the spring system is specified, the supply of compressed air only to the specified air spring system is stopped.

  The air spring control device according to claim 2 of the present invention is the air spring control device according to claim 1, wherein the air leak detection means operates the air pressure in the four air springs constituting the air spring group. Each of which has a pressure sensor for detecting information, and the vehicle height does not coincide with a target value even when compressed air is supplied for a predetermined determination time or more, and supply / exhaust of the air spring group is stopped An air spring system in which the output of the pressure sensor in a state is substantially equal to the atmospheric pressure is detected as an air spring system in which air leakage occurs.

  An air spring control device according to a third aspect of the present invention is the air spring control device according to the second aspect, wherein the determination time is set in accordance with a vehicle speed.

  According to the first aspect of the present invention, the air spring system in which air leakage has occurred is specified, and the supply of compressed air to only the specified air spring system is stopped. Even if a part of the air spring fails during driving (especially when the bottom of the air is exhausted), there is a single failure of the air spring. If it occurs only with the air springs of the system, the remaining three air line system air springs can continue to control the vehicle height relatively reliably and transport it to the destination without damaging the cargo in transit. it can.

  According to claim 2 of the present invention, it is attached to the detection of the air spring system in which air leakage has occurred for axle load control (for example, axle load movement control, axle load restriction, brakes). By effectively using (appropriating) the air pressure of the pressure sensor as the air spring operation information, it is possible to identify the air spring system in which air leakage occurs by the specific means, and thus avoid increasing the number of parts And increase in cost can be suppressed.

  According to the third aspect of the present invention, since the time for determining whether or not the vehicle height that is the air leakage condition matches the target value is set according to the vehicle speed, the control response and the control reliability are taken into consideration. Can be set, increasing the degree of freedom of control. In particular, it is possible to ensure control responsiveness by shortening the determination time when the data has a small vertical fluctuation, and to ensure control reliability by increasing the determination time when the data has a large vertical fluctuation.

  1 to 3 show a main part of a vehicle (truck) 1 on which an air spring control device according to an embodiment of the present invention is mounted. The vehicle 1 is a frame 2 on the vehicle body side, a front shaft 3 that pivotally supports a front wheel W1 (indicated by a two-dot chain line), a rear front shaft 4 that pivotally supports a rear front wheel W2 that is a driving wheel, and a driven wheel. A rear rear shaft 5 that pivotally supports the rear rear wheel W3, and front and rear suspension devices Sf and Sr interposed between the front and rear shafts 3, 4, and 5 and the frame 2 are provided.

  The front shaft 3 is connected to the frame 2 by arranging a leaf spring 6 and a shock absorber 7 constituting the front suspension device Sf symmetrically. On the other hand, the rear front shaft 4 and the rear rear shaft 5 are connected to the frame 2 via a rear air suspension device Sr described later. The rear air suspension device Sr is suspended on the frame 2 by arranging the front front shaft 4 and the rear rear shaft 5 symmetrically with front and rear leaf springs 8 and 9 and front and rear air springs 13 and 14, respectively.

  Front end portions of the front and rear leaf springs 8 and 9 arranged symmetrically are pin-coupled to the frame 2 side via front and rear spring brackets 11 and 12, respectively. The rear end portions of the leaf springs 8 and 9 are formed with lower spring receivers 801 and 901, and lower portions of the front and rear air spring systems 13 and 14 are attached to the lower spring receivers. The upper portions of the four front and rear air spring systems 13 and 14 arranged symmetrically are attached to upper spring receivers 802 and 902 formed on the frame 2, respectively. Shock absorbers 15 and 16 are also attached symmetrically between the rear front shaft 4 and the rear rear shaft 5 and the frame 2.

  As shown in FIG. 1, front and rear four-system air springs 13 and 14 arranged symmetrically are air distribution pipes a1 to a4 and an air source that form an air supply / exhaust system connection so that air supply and exhaust can be independently controlled for each system. It is connected to an air tank 17 in which high-pressure air is stored via a pipe b and a solenoid valve assembly 20 serving as an air supply / exhaust means. The air tank 17 is connected to an air compressor 18 so that high-pressure air with a constant pressure is always stored by driving the air compressor 18.

The solenoid valve assembly 20 serving as a supply / exhaust means includes a supply / discharge solenoid valve Vc connecting a high pressure port to the air source pipe b, and open / close valves V1 to V4 arranged opposite to the air tank 17, which are electronic control devices. The air suspension ECU 19 is connected.
The supply / discharge electromagnetic valve Vc is a three-way solenoid valve, and includes a high-pressure port e1 communicating with the air source pipe b, an exhaust port e2 discharging high-pressure air, and a supply / discharge port e3 communicating with all the on-off valves V1 to V4. I have. Each of the on-off valves V1 to V4 provides a first port g1 communicating with the supply / discharge port e3 of the supply / discharge electromagnetic valve Vc and the other port g2 communicating with the air springs 13 and 14 at corresponding positions.

  Here, when the supply / discharge solenoid valve Vc is on, the supply / discharge port e3 and the high-pressure port e1 are connected to supply high-pressure air to the air springs 13 and 14, and when the supply / discharge solenoid valve Vc is off, the supply / discharge port e3 and the exhaust port e2 are connected. The high-pressure air on each air spring side is switched to exhaust from the exhaust port e2. Each of the on-off valves V1 to V4 opens and closes according to the on / off output, and communicates between the air spring at the opposite position and the supply / exhaust port e3 of the supply / discharge electromagnetic valve Vc to block them. The supply / discharge electromagnetic valve Vc and the on-off valves V1 to V4 are driven by a switching signal from the air suspension ECU 19 as described later.

The air distribution pipes a1 to a4, which connect the front and rear air springs 13 and 14 and the on-off valves V1 to V4, which are symmetrically arranged in the air spring group, use the air pressure in each air spring as operation information. Pressure sensors Sp <b> 1 to Sp <b> 4 to be detected are attached, and air pressure information from these is input to the air suspension ECU 19.
The main part of the air suspension ECU 19 is formed by a microcomputer, and includes an arithmetic circuit 191, a RAM that forms a storage circuit, ROMs 192 and 193, input / output circuits 194 and 195, and is connected to a battery via a power supply circuit (not shown). The

The port of the output circuit 195 is connected to the supply / exhaust solenoid valve Vc, the on-off valves V1 to V4, the error indicator lamp Re, one system, and the two system failure error indicator lamps Re1 and Re2. The ports of the input circuit 194 include pressure sensors Sp1 to Sp4 for inputting spring air pressures sp1 to sp4, a vehicle speed sensor 21 for inputting a vehicle speed signal Vn, and left and right heights for outputting actual vehicle height signals H1 and H2 on the left and right sides of the vehicle body. Sensors 25 and 26 (vehicle height detection means), a height control switch 27 that outputs manually operated vertical operation signals Su and Sd, a target vehicle height setting switch 28 that outputs a target vehicle height setting signal M, and the like are connected. .
The air suspension ECU 19 constitutes a control function part of the air spring control device of the present invention, and has an air leak detection function and an air supply stop function in addition to the vehicle height control function.

  That is, the air suspension ECU 19 controls the vehicle height of the vehicle by controlling the supply and discharge of the compressed air to the front and rear four systems of air springs 13 and 14 that are arranged symmetrically as a group of air springs via the solenoid valve assembly 20. The vehicle height control function for controlling the air springs to coincide with the value and the air leakage of the air springs 13 and 14 of the four front and rear systems which are symmetrically arranged as a group of air springs, the spring air pressure sp1 which is the operation information of each air spring Air leak detection function including a specific function for determining whether or not an air leak has occurred based on .about.sp4 and actual vehicle height signals H1 and H2, and identifying the air spring system in which the air leak has occurred, and an air leak spring system Is specified, a supply air stop function for stopping supply of compressed air only to the specified air spring system is provided.

  FIG. 4 is a block diagram showing the control function unit of the air spring control device of the present invention. Here, the vehicle height control means A1 is connected to the four air springs 13 and 14 of the front and rear systems which are air spring groups via the supply / discharge electromagnetic valve Vc forming the electromagnetic valve assembly 20 (supply / exhaust means) and the on-off valves V1 to V4. By controlling the supply and discharge of compressed air, the height signal Hn corresponding to the height H of the loading platform D (see FIG. 2) is controlled to coincide with the target value Ho. The vehicle platform height signal Hn is detected by height sensors (vehicle height detection means) 25 and 26.

  The air leak detection means A2 detects air leaks in the four air springs 13 and 14 of the front and rear systems when the vehicle bed height signal Hn and the target value Ho do not coincide with each other continuously for a certain time. Further, the air leakage detection means A2 determines whether air leakage has occurred for each of the four air springs 13 and 14 based on the operation information of each air spring, and determines the air leakage spring in which the air leakage has occurred. It has a function as specifying means A2a for specifying.

The supply air stopping means A3 stops the supply of compressed air only to the specified air spring when the specifying means A2a specifies the air leakage spring.
Next, the operation of the air spring control device of FIG. 1 will be described along the vehicle height adjustment control routine and the air failure control routine of FIGS. 5 and 6 performed by the air suspension ECU 19.
In step s1 of the vehicle height adjustment control routine, the latest input signal from each sensor, the target vehicle height setting signal M from the target vehicle height setting switch 28, etc. are read and stored in each storage area. In step s2, whether the vehicle is stopped is determined based on the vehicle speed signal Vn <stop determination vehicle speed (for example, 4 km / h). When the vehicle stops below the stop determination vehicle speed, the process proceeds to step s3.

In step s3, if the target vehicle height setting signal M is input, the process proceeds to step s7, and if not, the process proceeds to step s5.
In step s5, it is determined whether or not the vertical operation signals Su and Sd are input from the height control switch 27. If there is no input, the control of this time is finished, and if there is, the process proceeds to step s6.

  In step s6, the loading platform is raised or lowered in accordance with the upper operation signal Su or the lower operation signal Sd. That is, when the upper operation signal Su is input, high pressure air is supplied to the four air springs 13 and 14 of the front and rear systems, which are the air spring group, and the vehicle height Hn is increased while the lower operation signal Sd is input. Then, while the signal is being input, air is exhausted from the exhaust port e2 of the supply / discharge electromagnetic valve Vc, the vehicle height Hn is lowered, and the platform D is aligned with the platform (not shown). Note that manual vehicle height adjustment by operating the height control switch 27 may be performed as necessary.

On the other hand, if the driver turns on the target vehicle height setting switch 28 and inputs the target vehicle height setting signal M in step s3, the process proceeds from step s3 to step s7 on the Yes side.
In step s7, if the target vehicle height setting signal M is input from the target vehicle height setting switch 28 for the first time in the current control routine, the target vehicle height Ho is set. The target vehicle height Ho is set to a value equal to the vehicle height Hn at the time when manual vehicle height adjustment is performed by the up / down operation signals Su, Sd in the previous control routine, and the up / down operation signal is set in the previous control routine. When manual vehicle height adjustment by Su and Sd is not performed, the vehicle is set as a value equal to the standard neutral vehicle height Hc that is initially set.

In step s8, the average value (H1 + H2) / 2 of the actual vehicle height signals H1, H2 from the left and right height sensors 25, 26 is obtained as the cargo bed height signal Hn.
In step s9, it is calculated whether or not the deviation between the target vehicle height Ho set in step s7 and the platform height signal Hn obtained in step s8 is within the stop allowable range α1. If it is within the allowable range α1, the control of this time is terminated. If it is not within the allowable range α1, the process proceeds to step s10.
In step s10, the vehicle height adjustment process is performed. If the target vehicle height Ho is reached before the predetermined time Ts has elapsed, the control of this time is terminated, and if not, the process proceeds to step s11 described later.

On the other hand, when traveling from step s2 to step s4, the average value (H1 + H2) / 2 of the actual vehicle height signals H1 and H2 is obtained as the platform height signal Hn, and the processing proceeds to step s12.
In step s12, a value equal to a preset standard neutral vehicle height Hc is set as the target vehicle height Ho, and the flow proceeds to step s13.
In step s13, it is calculated whether or not the deviation between the target vehicle height Ho and the platform height signal Hn is within the allowable travel time range α2 (> α1), and the control of this time is performed in step s14 outside the allowable range and within the allowable range. finish.

In addition, since the allowable range α2 for driving is set to a value larger than the allowable range α1 for stopping, this eliminates data variation due to disturbance due to starting, braking, road surface conditions, etc. during driving, and control responsiveness when stopping Is secured.
If the difference between the target vehicle height Ho and the platform height signal Hn does not fall within the travel allowable range α2 (> α1) and the process reaches step s14, a predetermined time (respective predetermined times Tr1 and Tr2 for low speed and high speed) elapses here. If the target vehicle height has been reached before, the control of this time is terminated, and if not, the process proceeds to step s11.

  These predetermined times Tr1, Tr2, and Ts are respectively a high travel time timer Tr2 with a vehicle speed of 20 km / h or more, a low speed timer Tr1 with a vehicle speed of less than 20 km / h, and a vehicle speed of less than 4 km / h. The hour timer Ts can be set to a smaller value in this order. For example, the high-speed running timer Tr2 is set to 60 seconds, the low-speed running timer Tr1 is set to 30 seconds, and the stop-time timer Ts is set to 10 seconds.

  As described above, since the determination time for determining whether the target vehicle height Ho and the loading platform height signal Hn coincide with each other is set according to the vehicle speed, the start, braking, road surface condition, etc. during traveling are larger as the vehicle speed is higher. Considering that the data varies due to disturbance, it is possible to suppress useless switching operations, to ensure control reliability, and to increase the degree of freedom of control. In particular, the control response can be ensured by shortening the determination time when the vehicle stops with little up and down fluctuation.

When proceeding from step s10 and step s14 to step s11, in step s11, the on-off valves V1 to V4 of all systems are closed, the error indicator lamp Re is turned on, and the air failure control routine (see FIG. 6) in step s15 is performed. Execute.
This is because it is determined that an air leak has occurred in any of the four front and rear air spring systems 13 and 14 because the target vehicle height Ho is not reached even if air is supplied continuously for a certain period of time or longer.

  In the air failure control routine shown in FIG. 6, the air pressure values of the latest four systems of pressure sensors Sp1 to Sp4 are read in step a1, and the air pressure values of the pressure sensors Sp1 to Sp4 are in the atmospheric pressure equivalent range in step a2. The air spring system in which air leakage has occurred is identified from the four front and rear air springs 13 and 14 which are air spring groups. In this process, since the open / close valves of all systems are closed in step s11, the air pressure value is maintained in the air spring system in which no air leakage occurs, whereas in the air spring system in which air leakage occurs, the air pressure value is maintained. This process is based on the pressure value reaching the atmospheric pressure equivalent range.

Each of the pressure sensors Sp1 to Sp4 is attached for axle load control (shaft load movement control, axle load restriction, brake time control) or the like that is not explained in the vehicle height adjustment control routine. However, it is possible to detect the atmospheric pressure by storing the signal values of the pressure sensors Sp1 to Sp4 when the atmospheric pressure is sensed in advance on the air suspension ECU side, and to determine whether the air leak has failed. In this respect, the number of parts and cost increase can be suppressed.
In step a3, it is determined whether or not there is one air leakage spring system. If one, the process proceeds to step a4, and if two or more, the process proceeds to step a5.

  In step a4, a setting process for fixing the on-off valve (one of V1 to V4) corresponding to the air leakage spring system specified in step a2 to be closed in the future is performed, and one system failure error indicator lamp Re1 is turned on. Return (failure mode 1). Thus, in the case of a rear two-axle vehicle, paying attention to the fact that even if one of the four air springs fails, if there are three remaining, the vehicle height can be adjusted and traveled to some extent. Only the open / close valve corresponding to the depressed air spring system is fixed to the closed side, and then the vehicle height adjustment control routine is restored to continue the vehicle height adjustment control again (fail-safe function).

In the automobile height adjustment control routine after reaching the failure mode 1, the air on / off valve system is fixed to the closed side in step s10 and step s14, so that air is not supplied or discharged, and the remaining 3 For the air spring group of the system, the vehicle height adjustment process is performed to cancel the deviation between the target vehicle height Ho and the loading platform height signal Hn.
On the other hand, in step a3, it is determined that there are two or more air leakage springs. When step a5 is reached, the top priority is to maintain running stability until returning to the maintenance shop for repair and inspection of the failed part. The error indicator lamp Re2 is turned on, and the vehicle height adjustment control is terminated. At this time, since all the on-off valves V1 to V4 are closed in step s11, they are fixed on the closed side (failure mode 2).

  As described above, in the air spring control device of FIG. 1, in the failure mode 1, even if a failure (air leakage) occurs in the air spring of a single air line system, the remaining three air line systems Focusing on the fact that the height of the vehicle can be adjusted with the air spring, the air leakage spring system in which air leakage has occurred is identified, and only the on-off valve corresponding to the identified air spring system is stopped. The air spring can maintain the height adjustment control of the vehicle, and even if a single air spring fails during transportation, the three systems can run without the bottomed out state of air and damage the load. The operation can be continued without any problems.

  Further, in the air spring control device of FIG. 1, the determination time as to whether or not the air pressure value of each of the pressure sensors Sp1 to Sp4, which is an air leakage condition, has reached the atmospheric pressure equivalent range may be set according to the vehicle speed. In this way, the determination time is set in consideration of control responsiveness and control reliability, and the degree of freedom of control is increased. In particular, when the vehicle has a small up-and-down fluctuation in the data, the judgment time can be shortened to detect air leaks with good responsiveness, and when traveling with a lot of up-and-down fluctuations in the data, the judgment time can be lengthened to avoid erroneous judgment of air leaks. Control can be performed.

  In the above description, the four air springs 13 and 14 in the front and rear are configured by a single air spring. However, one air spring may be configured by a plurality of air springs.

  Further, in the above description, the air leak detection means is such that the air pressure values of the pressure sensors Sp1 to Sp4, which are the operation information of each air spring system, are equivalent to the atmospheric pressure for the four air springs 13 and 14 of the front and rear systems which are air spring groups. In the four air springs 13 and 14, the air spring in which the air leakage has occurred is specified, but instead of this, the four air springs 13 and 14 are identified. A limit switch (not shown) that can detect the bottom where the upper and lower spring holders of the air spring overlap is attached to each of the air springs, and an air leak is generated by using a bottom signal as operation information of the limit switch May be specified.

  Even in such a configuration, the same operations and effects as those of the air spring control device of FIG. 1 can be obtained in the components other than using the limit switch (not shown) instead of the pressure sensors Sp1 to Sp4.

  As described above, the air leakage detection means sets the remaining three lines of air as the failure mode 1 when one of the four air springs 13 and 14 of the front and rear systems which are the air spring group has an air leakage failure. The springs 13 and 14 are controlled to adjust the vehicle height. However, in some cases, even if one of the left and right air springs 13 and 14 in the front and rear systems has an air leakage failure, the failure mode 1, the remaining two air springs 13 and 14 may be subjected to vehicle height adjustment control. In this case as well, the same operation and effect as the air spring control device of FIG. 1 can be obtained.

  As described above, the rear air suspension device Sr mounted with the air spring control device of FIG. 1 has a configuration in which the rear front shaft 4 as a driving shaft and the rear rear shaft 5 as a driven shaft are mounted. The present invention can be applied even when both the rear front shaft and the rear rear shaft are drive shafts, and the air spring control according to the present invention is applied to a rear air suspension device provided with four air springs in the rear two shafts. The apparatus can be mounted in the same manner, and the same effect can be obtained.

  In the above description, the air spring control device is mounted on the rear two-axle truck, but can be similarly applied to other rear two-axle vehicles such as buses.

It is a schematic block diagram at the time of applying the air spring control apparatus concerning one Embodiment of this invention to the rear air suspension apparatus of a track | truck. FIG. 2 is a cutaway side view of a front and rear air suspension device of a truck to which the air spring control device of FIG. 1 is applied; FIG. 2 is a cutaway perspective view of a main part of a front and rear air suspension device for a track to which the air spring control device of FIG. 1 is applied. It is a block diagram of the control function part of the air spring control apparatus of FIG. 3 is a flowchart of a vehicle height adjustment control routine that is performed by an air suspension ECU of the air spring control device of FIG. 1. 2 is a flowchart of an air failure control routine performed by an air suspension ECU of the air spring control device of FIG. 1. It is a schematic block diagram of the conventional air spring control apparatus.

Explanation of symbols

1 Vehicle (truck)
4 Rear front shaft 5 Rear rear shaft 13, 14 Air spring 17 Air tank 19 Air suspension ECU
20 Solenoid valve assembly forming air supply / exhaust means 25, 26 Left and right height sensors (vehicle height detection means)
a1 to a4 Air distribution pipe (exhaust system connection part)
b Air source piping (exhaust system connection)
sp1 to sp4 Spring air pressure (operation information)
A1 Vehicle height control means A2 Air leak detection means A2a Identification means A3 Air supply stop means D Cargo bed Hn Cargo bed height signal Ho Target value (car height)
Post-Sr suspension device V1-V4 On-off valve Vc Supply / discharge solenoid valve

Claims (3)

It is equipped on the rear two-axle cargo vehicle,
An air spring group consisting of four air springs mounted between both ends of each of the rear two shafts and the loading platform of the vehicle;
An air tank that accumulates compressed air;
An air supply / exhaust system connecting portion for connecting the air tank and the air spring group;
An air supply / exhaust means for supplying or exhausting compressed air accumulated in the air tank to the air spring group provided in the air supply / exhaust system connecting portion;
Vehicle height detecting means for detecting the vehicle height of the vehicle;
Control means for controlling the vehicle height to coincide with a target value by controlling the supply and discharge of compressed air to and from the air spring group via the air supply and exhaust means;
Air leakage detection means for detecting air leakage of the air spring group;
An air supply stop means for giving priority to the control means and stopping the supply of compressed air to any of the four air springs;
In an air spring control device having
The air leakage detection means determines whether air leakage has occurred for each of the four air springs based on the operation information of each air spring system, and identifies the air spring system in which the air leakage has occurred Having means,
The air supply control means is characterized in that when the specifying means specifies an air spring system in which air leakage occurs, the supply of compressed air only to the specified air spring system is stopped. apparatus. The air spring control device according to claim 1,
The air leak detection means has pressure sensors for detecting the air pressures in the four air springs constituting the air spring group as the operation information, and the specifying means supplies compressed air for a predetermined determination time or more. Even if the vehicle height does not match the target value, and the air spring system has an air leak in the air spring system in which the output of the pressure sensor is substantially equal to the atmospheric pressure in a state where supply and exhaust of the air spring group is stopped. 2. The air spring control apparatus according to claim 1, wherein the air spring system is detected as an air spring system. In the air spring control device according to claim 2,
The air spring control device characterized in that the determination time is set according to a vehicle speed.

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